GEARBOX, IN PARTICULAR A TWIN GEARBOX, AND BEARING BRACKET WITH AN ADVANTAGEOUS OIL LUBRICATION BY MEANS OF A MULTI-CHAMBER SYSTEM, AS WELL AS METHOD SUITABLE FOR LUBRICATING SUCH A GEARBOX

Abstract

A twin transmission of a dual electric machine powertrain is presented. The twin transmission has a gear stage, a sump, a multi-chamber system adjacent to the gear stage, and a delay arrangement with a hydraulic flow restrictor. The multi-chamber system provides a flow path that continuously delivers a lubricant into the sump through the hydraulic flow restrictor.

Claims

1.-16. (canceled)

17. A twin transmission of a dual electric machine powertrain, the twin transmission comprising: a gear stage including a first gear and a second gear, the second gear being a centrifugal lubricating film separator gear, the second gear being at a highest gear location of the twin transmission in a mounting orientation of the twin transmission corresponding to a mounted position of the twin transmission in the powertrain; a sump, into which at least the first gear is configured to dip with at least one gear segment; a multi-chamber system adjacent to the gear stage; and a delay arrangement comprising at least one hydraulic flow restrictor, the multi-chamber system being configured to provide a flow path that continuously delivers a lubricant into the sump through the at least one hydraulic flow restrictor of the delay arrangement.

18. The twin transmission according to claim 17, wherein the twin transmission is a passively lubricated transmission.

19. The twin transmission according to claim 17, wherein the at least one hydraulic flow restrictor is selected from the group consisting of a nozzle, a shutter, a choke, and a flow valve.

20. The twin transmission according to claim 17, comprising two sub-transmissions, each sub-transmission being a two-stage or three-stage spur gear transmission comprising at least said first gear and said second gear, wherein at least one of said first gear and said second gear are stepped gears arranged in a contiguous internal volume within a transmission case.

21. The twin transmission according to claim 17, wherein the multi-chamber system comprises at least three chambers.

22. The twin transmission according to claim 17, wherein the multi-chamber system comprises plural chambers, from which lubricant located therein is able to run off under gravity, said plural chambers including an uppermost chamber from which the lubricant has a longest run-off distance under gravity, said uppermost chamber being a drip and collection chamber.

23. The twin transmission according to claim 17, wherein the multi-chamber system comprises a middle chamber, said middle chamber being a first reservoir chamber configured to hold lubricant ready for delayed discharge.

24. The twin transmission according to claim 23, wherein the delay arrangement is placed on a discharge side of the first reservoir chamber.

25. The twin transmission according to claim 17, wherein the twin transmission is configured with two three-stage transmission paths arranged in parallel, each transmission path comprising said gear stage, said sump, said multi-chamber system and said delay arrangement, wherein each transmission path is configured for a separate powertrain of the dual electric machine powertrain, and each transmission path comprises a connection, for drive purposes, to one separate electric machine of the dual electric machine powertrain.

26. The twin transmission according to claim 17, wherein the sump adjoins a lowermost chamber of the multi-chamber system, or alternatively the lowermost chamber merges into the sump.

27. The twin transmission according to claim 17, further comprising: at least one splash tooth; and a gear lubrication pan at a distance from the sump, the gear lubrication pan comprising a flow-off barrier to prevent lubricant from flowing off into the sump, the flow-off barrier being configured to allow a lubricant level in which the at least one splash tooth fits for splashing.

28. The twin transmission according to claim 17, further comprising output shafts having third gears and bearings, the output shafts being supported at their ends by a single spectacles-type bearing bracket configured as a single-hole support structure.

29. The twin transmission according to claim 28, wherein the spectacles-type bearing bracket is a plate tapering toward its edges, the plate being shaped around a central opening.

30. A dual electric machine powertrain comprising the twin transmission of claim 17.

31. The twin transmission according to claim 17, wherein the second gear is configured to rotate at a medium speed.

32. The twin transmission according to claim 17, wherein the twin transmission is a pump-free transmission, configured for: lubricant distribution taking place counter to gravity, wherein lubricant is provided over running surfaces of the first gear and the second gear by rotations of the first gear and the second gear; and gravity-aided delayed lubricant dispensing.

33. The twin transmission according to claim 17, further comprising a transmission case having a first reservoir chamber or having a first reservoir chamber and a second reservoir chamber of the multi chamber system inside the transmission case, at least one of said reservoir chambers having a wall with a discharge side, the wall comprising a hydraulic flow restrictor of the delay arrangement being placed at a location of the wall at a lowest point in the wall while the transmission case is in the mounting orientation.

34. The twin transmission according to claim 17, having an open flow path configured for continuous lubricant reflux after a first start-up phase, wherein the multi-chamber system is configured to passively remain in an open state after an end of operation of the twin transmission, thus providing said open flow path.

35. The twin transmission according to claim 29, further comprising stabilizing webs protruding from said plate into spaces for two drive gears, said plate comprising at least one lubrication nozzle opening radially into a bearing lubrication chamber between the bearings, the lubrication nozzle configured for being supplied with oil from a lubrication reservoir of a reservoir chamber, the lubrication reservoir being designed for collecting splash oil via oil guiding surfaces of the spectacles-type bearing bracket.

36. A spur gear transmission of a dual electric machine powertrain, comprising gears inclusive of a first gear with splash teeth, a multi-chamber system, a transmission case, a sump and a delay arrangement, wherein the transmission case is configured for a passive lubricating film distribution, wherein lubricant stays distributed over all the running surfaces of the spur gear transmission by rotation of the gears, at least one surface inside the transmission case is arranged with an angle or a slope for guiding the lubricant towards or inside the multi-chamber system, one chamber of the multi chamber system is a receiving chamber for the lubricant after being splashed as a result of a centrifugal force inside the transmission case, the one chamber being configured for retaining the lubricant inside the transmission case in order to be stored in a further chamber of the multi-chamber system, the delay arrangement is arranged in a lubricant flow path of the multi-chamber system, the lubricant flow path providing a path for the lubricant recirculating back into the sump in a delayed manner, and the first gear with splash teeth is configured to convey the lubricant upwards from the sump by rotation of the first gear for surface lubrication.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0134] The present invention can be understood even better if reference is made to the accompanying figures which show particularly advantageous design possibilities by way of example, without limiting the present invention thereto, wherein

[0135] FIG. 1 schematically shows a motor vehicle with an electric drive,

[0136] FIG. 2 schematically shows a modified embodiment of a motor vehicle with an electric drive,

[0137] FIG. 3 shows a cross-section through a dual transmission,

[0138] FIG. 4 shows a second cross-section through the dual transmission, which is oriented perpendicular to the cross-section of FIG. 2,

[0139] FIG. 5 shows a plan view of a spectacles-type bearing bracket, with a section plane being indicated,

[0140] FIG. 6 shows a cross-sectional view according to FIG. 5,

[0141] FIG. 7 shows a perspective view of the spectacles-type bearing bracket, and

[0142] FIG. 8 shows an exploded view of an arrangement, in particular of a spur gear as an output gear (see FIG. 3), between a removable spectacles-type bearing bracket and a transmission sub-case.

DESCRIPTION OF THE FIGURES

[0143] FIG. 1 and FIG. 2 schematically show a motor vehicle 500 or 500.sup.I which, in addition to the space for the driver, which is identifiable by the steering wheel 514 and can also be referred to as the driver's cab or passenger compartment, has a rear 526 and a trunk region 528, identifiable by the marked direction of travel 502. Located in the front part of the passenger compartment, as usual, is the steering wheel 514, which can transmit a driver's steering movements to two wheels as road wheels 510, 512 or vehicle wheels 510, 512 via a steering linkage 516 consisting of a steering shaft, a steering transmission, track rods and wheel steering levers. Two further road wheels 506, 508 are mounted on a second axle, the vehicle rear axle 518 or 518.sup.I. The road wheels 506, 508 are driven via half-axles 520, 522. The half-axles 520, 522 may be formed by universal (joint) shafts, for example. The half-axles 520, 522 are attached to the output side of a dual transmission 1 or 1.sup.I. A first electric machine 5 or 5.sup.II and a second electric machine 7 or 7.sup.II are attached to the drive side of the dual transmission 1 or 1.sup.I. The electric machines 5, 7 or 5.sup.II, 7.sup.II and the half-axles 520, 522 are each attached in pairs to the same sides of the transmission 1 or 1.sup.I. Torque from the electric machine 5 or 5.sup.II is applied to an input shaft 33 (see FIG. 3) of the dual transmission 1 or 1.sup.I via a respective side, and the first half-axle 520, and thus the output to the first road wheel 506, is attached on the same side of the transmission 1 or 1.sup.I. In the same way, torque from the electric machine 7 or 7.sup.II is applied to an input shaft 35 (see FIG. 3) of the dual transmission 1 or 1.sup.I, and the second half-axle 522, and thus the output to the second road wheel 508, is arranged on the same side of the dual transmission 1 or 1.sup.I.

[0144] A particularly advantageous motor vehicle body exists if the electric machines 5, 7, which in FIG. 1 are mounted in front of the half-axles 520, 522 in the direction of travel 502, are mounted behind the half-axles 520, 522 as shown on the basis of the electric machines 5.sup.II, 7.sup.II in FIG. 2, for example in that the symmetrically constructed dual transmission 1 is rotated through 180° in the illustrated plane of the vehicle floor 504 of FIG. 1 and in particular mounting points for the dual transmission 1 and the electric machines 5, 7 are provided underneath the trunk 528. As shown in FIG. 2, however, a powertrain 3.sup.I comprising a dual transmission 1.sup.I can also be constructed in a motor vehicle 500.sup.I, the gears (see FIG. 3) of said transmission being designed to transmit power in an arrangement of the electric machines 5.sup.II, 7.sup.II behind a rear axle 518.sup.I.

[0145] According to FIG. 1 and according to FIG. 2, an electric accumulator 9 is located in the region of the vehicle floor 504, which accumulator, via electrical leads 11, 13, can provide electrical energy to the electric machines 5, 7 or 5.sup.II, 7.sup.II and the motor controls thereof (not shown). The powertrain 3 or 3.sup.I thus extends from the accumulator 9, via the electrical leads 11, 13, via the electric machines 5, 7 or 5.sup.II, 7.sup.II and the motor controls thereof, via the dual transmission 1, and via the half-axles 520, 522, to the road wheels 506, 508. Each electric machine 5, 7 or 5.sup.II, 7.sup.II thus drives one road wheel 506, 508. This is a single-wheel drive.

[0146] The transmission 1 or 1.sup.I is arranged on the vehicle longitudinal axis 524. One electric machine 5 or 5.sup.II and one half-axle 520 are located on one side of the vehicle longitudinal axis 524, while the other electric machine 7 and the other half-axle 522 are arranged on the other side of the longitudinal axis 524. The electric machine 5 or 7, which according to FIG. 1 is arranged close to the center and rotates transversely to the vehicle longitudinal axis 524, rotates the transmission 1 so that, on the output side, an output shaft 37, 39 (see FIG. 3) can apply a torque to a wheel 506 or 508 likewise transversely to the vehicle longitudinal axis 524. The electric machine 5.sup.II or 7.sup.II, which according to FIG. 2 is arranged close to the trunk and rotates transversely to the vehicle longitudinal axis 534, rotates the transmission 1.sup.I so that, on the output side, an output shaft 37, 39 (see FIG. 3) can apply a torque to a wheel 506 or 508 likewise transversely to the vehicle longitudinal axis 524. As shown in FIG. 1 or FIG. 2, for such a drive connection, the electric machine 5, 7 or 5.sup.II, 7.sup.II is attached to the input shaft 33, 35 (shown in FIG. 3) by a coupling 532, 534. The transmission 1 or 1.sup.I and the electric machines 5, 7 or 5.sup.II, 7.sup.II are coupled.

[0147] The vehicle 500 or 500.sup.I shown in FIG. 1 or FIG. 2 is driven via its vehicle rear axle 518 or 518.sup.I. This is an electric rear axle drive using the dual transmission 1 or 1.sup.I. The dual transmission 1 or 1.sup.I is arranged in the region of the rear compartment 526 or in the region of the trunk 528, and in each case in the region of the vehicle floor 504.

[0148] Interesting aspects of the dual transmission 1 will be explained below primarily on the basis of FIG. 3 and FIG. 4. It is particularly helpful to consider the two figures, FIG. 3 and FIG. 4, jointly with the following text. FIGS. 5 to 8 are to be included in addition to what is stated below because advantageous aspects or components and arrangements, by which a transmission can be further developed, will also become apparent from these figures.

[0149] The transmission 1 is shown in a sectional view in FIG. 3, in which the section is made through the individual gear centers 25, 27, 29.

[0150] As already discussed above, the dual transmission 1 shown in greater detail in FIG. 3 is shown in FIG. 1 in an installation position on the vehicle longitudinal axis 524 of a vehicle, such as the vehicle 500, in order to drive two wheels 506, 508 individually. The dual transmission 1 thus forms part of an electrically powered motor vehicle 500, more precisely the powertrain 3 thereof. The transmission 1.sup.I of FIG. 2 can be designed in the manner of a transmission 1 according to FIG. 3 or in the manner of a transmission 1.sup.I according to FIG. 8, the transmission case in each case having attachment points for mounting it in the vicinity of the trunk (not shown).

[0151] As shown in FIG. 3, the dual transmission 1 has two single transmissions 15, 17, each single transmission 15, 17 being designed as a two-stage spur gear transmission. Each spur gear transmission has three positions 19, 21, 23 for gear centers 25, 27, 29 in a single, common transmission case 31. A drive torque 5.sup.I, 7.sup.I is applied by the electric machines 5, 7 (see FIG. 1) to the respective input shaft 33, 35. The input shafts 33, 35 connected to the respective electric machines 5 and 7 (see FIG. 1) and the output shafts 37 and 39 connected to the respective half-axles 520 and 522 are arranged at the same height in a middle region M in relation to a transverse extension, i.e. in particular a relatively short distance from one case wall 41 to an opposite case wall 43 of the transmission case 31. The position of the input shafts 33, 35 and of the output shafts 37, 39, which define the gear centers 25 and 29, describes a reference plane B within the transmission case 31. A middle axle 45, which describes the gear center 27 or a position that is a middle gear center, is in a parallel and elevated position relative to the reference plane B and forms a position of the gear center 27 at a distance from the transmission case bottom.

[0152] The two input shafts 33, 35 are combined to form a dual input shaft 32. They are mechanically connected to form the dual input shaft 32. The two input shafts 33, 35 extend along the axis 44 and in this way form the dual input shaft 32. The two coaxially arranged input shafts 33, 35 are connected to each other in such a way as to be rotatable relative to each other.

[0153] The middle axle 45 can be intersected by a straight line G (see FIG. 4) connecting the gear center 25 or 29 and the middle axle 45, namely in an angle range of around 5° to 70° in relation to a connecting line, intended as a design aid, between the gear centers 25 and 29.

[0154] As can likewise be seen from FIG. 3, the way in which the gear centers 25, 27, 29 are to be located depends on the on the gears 75, 75.sup.I of the input shafts 33, 35, the gears 77, 77.sup.I of the output shafts 37, 39 and the gears 49, 49.sup.I, 50, 50.sup.I of the toothing geometries selected on the middle axle 45, as well as on the powers to be transmitted. On account of being driven by the drive torques 5.sup.I, 7.sup.I, the gears 75, 75.sup.I are the first gears in the flow of torque through the transmission 1.

[0155] The respective gear 75, 75.sup.I on the input shaft side of each single transmission 15, 17 drives a respective gear 49, 49.sup.I on the middle axle 45. In the exemplary embodiment shown, the directions of rotation of the electric machines 5, 7 (see FIG. 1) in the traction mode of the vehicle are selected in such a way that the gear 49, 49.sup.I has a direction of rotation rotating away from the case bottom 51 of the transmission case 31 following gear contact in a driving manner.

[0156] If, in a manner differing from the advantageous motor vehicle body shown in FIG. 1 and described in this connection, a motor vehicle body is realized with a transmission arrangement as shown in FIG. 2, in which the transmission arrangement is turned through 180° in comparison to the transmission arrangement in FIG. 1, then a direction of rotation rotating toward the case bottom 51 of the transmission case would be set for the gear 49, 49.sup.I following gear contact.

[0157] According to FIG. 3, when a transmission case 31 of the transmission 1 is in an installed state in a motor vehicle (see motor vehicle 500 or 500.sup.I in FIG. 1 or FIG. 2), the case longitudinal direction 120 is oriented parallel to the vehicle longitudinal axis (see vehicle longitudinal axis 524 in FIG. 1 or FIG. 2). The transmission case 31 has a greater extension in its case longitudinal direction 120 than in its width 106.

[0158] As illustrated in particular in FIG. 3, the axle 45 defining the middle position or the middle gear center 27 is designed as a stationary axle which is fixed to the case. This makes it possible to stiffen the transmission case 31 without the need for additional components. The respective output gear 49, 49.sup.I on the axle 45 and the driving gear 50, 50.sup.I are borne on the axle 45 via in each case two needle bearings 61, 63 in order to avoid any tilting of the gears 49, 49.sup.I, 50, 50.sup.I, which are moreover preferably formed as a one-piece stepped gear.

[0159] In contrast, the input shafts 33, 35 and the output shafts 37, 39 are mounted by way of rolling bearings 65, 67, 69 and 71 in outer walls of the transmission case 31. Furthermore, the input shafts 33, 35 are mounted by means of ball bearings in the vicinity of a case partition wall 73 that has apertures, such as the aperture 212, for the joint lubrication of the single transmissions 15 and 17. A wall support 210, designed as part of the case partition wall 73, establishes a connection to the transmission case 31. The output shafts 37 and 39 are mounted in a second case partition wall 73.sup.I, more precisely a spectacles-type bearing bracket, by means of needle bearings (without reference signs) or one needle bearing per single transmission 15, 17.

[0160] As can be seen particularly well from looking at the sub-transmission 17 shown FIG. 4, the input shaft 33 and the output shafts 39 are arranged lower than the axle 45 in relation to the case bottom 51 of the transmission case 31.

[0161] The stepped gears, such as the stepped gear 79 on the axle 45 (see FIG. 3), have a first, larger diameter d.sub.1 on the drive side and a smaller, second diameter d.sub.2 on the output side. There is a step-down ratio toward the output side. The two gears 49, 50 are joined together to form a stepped gear 79. It can also be said that the two gears 49, 50 or 49.sup.I, 50.sup.I are welded together to form a stepped gear 79 or 79.sup.I. Accordingly, a second gear pair 49.sup.I, 50.sup.I is mounted as a stepped gear 79.sup.I. Depending on the manner of counting, gear pairs 49, 50; 49.sup.I, 50.sup.I which are arranged for conjoint rotation, such as the stepped gear 79, can be referred to as second gears or as second (50, 50.sup.I) and third gears (49, 49.sup.I).

[0162] In the dual transmission 1 according to the invention, as shown in FIG. 3, a first gear stage 53 or first ratio 53 is created, which forms a ratio turning away from the case bottom 51 of the transmission case 31, as well as a second gear stage 55 or the second ratio 55, which forms a ratio turning toward the case bottom 51. On the other hand, the gear pairing consisting of the first two gears 75.sup.I, 49.sup.I in the flow of torque in the transmission 1 creates the ratio 53.sup.I. The gear pairing consisting of the subsequent two gears 50.sup.I, 77.sup.I creates the ratio 55.sup.I.

[0163] As shown in particular by FIG. 3 in a schematic longitudinal section through the dual transmission 1, the middle gears 49, 50 or 49.sup.I, 50.sup.I, which are formed in one piece with each other, are designed to transmit a torque in a manner free of transverse forces due to the fact that the teeth 57 and 59 or 57.sup.I and 59.sup.I of two adjacent gears 49, 50 or 49.sup.I, 50.sup.I are provided with different angles of inclination for each row of teeth, such as the angles of inclination β.sub.1 and β.sub.2. The angles of inclination β.sub.1, β.sub.2 are indicated only schematically in the illustrated section plane of FIG. 3. The teeth 57, 59 in the sub-transmission 17 as well as adjacent teeth of the respective rows of teeth (without reference signs) extend with respective tooth directions in a parallel manner through the section plane of FIG. 3. In relation to a specified or selected direction of the middle axle 45, the teeth 57, 59 or the running surfaces thereof extend with a tooth direction laterally toward the other sub-transmission 15 or away from the other sub-transmission 15, wherein a deviation, expressible by vectors, of the tooth directions of the teeth 57, 59 from the direction of the middle axle 45 in each case has the same sign (identical sign in the angles of inclination).

[0164] For the gears 49.sup.I, 50.sup.I and the teeth 57.sup.I, 59.sup.I of the other single transmission 15, the same applies on account of an identical design of transmission parts, i.e. the sub-transmission 15, which is constructed in a manner identical to the sub-transmission 17, has adjacent gears 49.sup.I, 50.sup.I which are designed with a corresponding inclination of the teeth 57.sup.I, 59.sup.I. In other words, what has been described above correspondingly applies to the gears 49.sup.I, 50.sup.I and the teeth 57.sup.I, 59.sup.I of the other single transmission 15 due to an identical design of transmission parts.

[0165] The gears 49, 50 or 49.sup.I, 50.sup.I are free of axial forces, at least in the traction mode of the vehicle.

[0166] It may be advantageous to provide thrust washers to support the gears 49, 50 or 49.sup.I, 50.sup.I on the transmission case 31.

[0167] Furthermore, in order to vent the transmission case 31, instead of a solid middle axle it may be advantageous to provide the middle axle 45 as a sleeve or to additionally provide a sleeve on the middle axle 45, which sleeve makes it possible to equalize the pressure in the transmission case 31.

[0168] The gears 49, 49.sup.I, 50, 50.sup.I, 75, 75.sup.I, 77 and 77.sup.I are formed as disk wheels on account of the high torques to be transmitted. As shown in FIG. 3, the gears 77, 77.sup.I on the output shaft side are formed by a disk that has a thickness smaller than the width of their gear rim. In addition, the respective disk of the gears 77, 77.sup.I is at an angle to the respective output shaft 37, 39, i.e. it may be formed at a non-perpendicular angle to the respective output shaft 37, 39. The disk has a base with an end face that extends radially from the output shaft 37, 39 or merges into the output shaft 37, 39 and in particular bounds a running surface of a needle bearing in an axial direction.

[0169] All the gears 49, 49.sup.I, 50, 50.sup.I, 75, 75.sup.I, 77, 77.sup.I, axles and shafts 33, 35, 37, 39 installed in the transmission case 31 are lubricated via a common sump (see FIG. 4). Each single transmission 15, 17 has a step-down ratio of, for example, 8.5:1 or even 12:1.

[0170] In a regular filling state, the transmission case 31 is filled with a transmission oil, but not completely filled with oil; instead, part of the interior, i.e. part of the internal volume 108 of the transmission case 31 is filled with air.

[0171] By way of its internal cavity, the transmission 1 shown in FIG. 3 with its transmission case 31 creates an internal volume 108 that extends from the first inner side 102 thereof to the second inner side 104 thereof. However, volume-reducing components are arranged in the internal volume 108. One component that reduces the internal volume 108 is an oil-guiding wall 226. The internal volume 108 is partly reduced by the gears, such as the gears 49, 49.sup.I, 50, 50.sup.I, 75, 75.sup.I, 77, 77.sup.I, by shafts, such as the shafts 33, 35, 37, 39, and by other components, such as needle bearings 61, 63 and rolling bearings, as well as by a sleeve 116. The free internal volume 108 is reduced by the installed components. The remaining internal volume 108 is filled to a certain level with a transmission fluid, such as a transmission oil, for operating the transmission 1. Air remains in the rest of the internal volume 108.

[0172] The internal volume 108 is partly split into chambers. The oil-guiding wall 226 separates regions of the internal volume 108 from each other. The oil-guiding wall 226 is connected to the transmission case 31. Provided in the region of a center 110 of the transmission 1 is the wall support 210 of the oil-guiding wall 226, which at the same time is designed as a bearing support for two shafts 33, 35. The wall support 210 separates a collection chamber 204.sup.I of one single transmission 15 from a collection chamber 204 of the other single transmission 17. In the wall support 210, at least one equalizing flow opening 212 ensures an equalization of the level of transmission oil in the collection chambers 204, 204.sup.I between the single transmissions 15, 17.

[0173] In other words, the single transmissions 15, 17 are decoupled from each other in terms of torque transmission, but are coupled to each other in terms of lubrication. A needs-based lubrication of the transmissions takes place through separate, but oil-permeable, regions of the internal volume 108 with the aid of delay means for a flow of transmission oil, such as the delay means 180.sup.II, as will be explained in greater detail below.

[0174] For air that is to pass outward via a bore 118 in the sleeve 116 to a breather cap 130 in order to be discharged, a vent structure is incorporated in the transmission 1.

[0175] The sleeve 116, which is hollow due to a bore 118, is located in the region of the gear axle 114 among the gear pairs 49, 50 or 49.sup.I, 50.sup.I designed as stepped gears 79. The cavity created by the bore 118 in the interior of the sleeve 116 has connections to the rest of the internal volume 108 of the transmission 1.sup.I or of the transmission case 31 via further bores 118.sup.I, 118.sup.II.

[0176] The sleeve 116 extends from one inner side 102 to the opposite inner side 104 of the transmission case 31. The sleeve 116 is a transverse strut that stiffens the case 31. The (internal) width 106 of the transmission case 31 is completely spanned by the sleeve 116. The sleeve 116 therefore extends from a first case wall 41 to a second case wall 43.

[0177] Advantageously, the sleeve 116 is located in a middle region M of the transmission 1. The middle region M of the transmission 1 is used by the second, middle position 21 to center gears 49, 49.sup.I, 50, 50.sup.I.

[0178] Via the (feed) bores 118.sup.I, 118.sup.II, air from the internal volume 108, namely from anywhere therein so long as it is somehow distributed over the width 106, can enter the centrally arranged bore 118 of the sleeve 116, which in particular spans the width 106 of the case 31. The air then passes to the breather cap 130. The case wall 41, 43 may contain further bores (not shown), which extend partially along the case wall 41, 43 and via which air enters the bore 118 that spans the width 106 of the case 31. Such bores in the case wall also serve to supply oil to the needle bearings of the gears 49, 49.sup.I, 50, 50.sup.I.

[0179] As can be seen from looking at the details of FIG. 3, a narrower portion 136 is connected to the thicker portion 134 outside of the center 110 of the transmission 1. The narrower portion 136 of the vent extends over less than half the distance of the sleeve 116, in particular in the width direction.

[0180] FIG. 4 schematically shows, along a broken line A, a cross-section through the dual transmission 1, which was shown in a different sectional view in FIG. 3. The two section planes, that of FIG. 3 and that of FIG. 4, are perpendicular to each other. FIG. 4 shows a sectional view through the second sub-transmission 17. For better clarity, some details from FIG. 3, such as the sleeve 116, which have already been explained in detail on the basis of FIG. 3, are shown in simplified form in FIG. 4.

[0181] A corresponding section through the first sub-transmission 15, which is likewise shown in FIG. 3, would show a structure identical to that of FIG. 4. In FIG. 4, the sub-transmission 17 is surrounded by the transmission case 31. A first gear 77, having a gear center 29 arranged on the output shaft 39, and a further gear 50, which can be referred to as the second gear, are shown. The first gear 77 meshes with the second gear 50, which is seated on the stationary gear axle 114 or on the middle axle 45. The second gear 50, together with a third gear 49, forms a stepped gear 79. In the illustrated design of the dual transmission 1, it can also be said that the gear axle 114 is arranged higher than the output shaft 39, which is arranged at the same level as the input shaft 35 in relation to a vehicle footprint or a road (not shown). By way of example and to illustrate the geometry, the centers 25 and 45 are connected by a dash-dotted straight line G. The input shaft 35 carries a fourth gear 75, which meshes with the third gear 49. The stepped gear 79 arranged on the gear axle 114 is lubricated indirectly.

[0182] Hereinbelow, the description will focus on individual aspects of the lubrication, in particular the oil lubrication.

[0183] The transmission sump 160 is located in a bottom region of the dual transmission 1. The bottom region is also referred to as the sump 160 because it accommodates the lubricant 162 in the case 31 when the dual transmission 1 is in a rest state. A first lubricant level 164 of the sump 160 is set. The lubricant level 164 can also be referred to as the fill level. A first gear segment 240 of the first gear 77 dips into the lubricant 162. When the dual transmission 1 is set in rotation by a motor drive, for example to move the motor vehicle 500 or 500.sup.I shown in FIG. 1 or FIG. 2 in a forward direction, the first gear 77 moves with a direction of rotation 260. Splash teeth, such as the first splash tooth 230, rotate with the gear 77 through the sump 160 and convey lubricant 162 upward. A second gear segment 242 has to move past the second gear 50 before lubricant 162 that is conveyed by the first gear 77 can reach the second gear 50 or the running surface 250 of the gear through transportation. The excess lubricant 162 transferred from the first gear 77 to the second gear 50 is transported onward before being removed by centrifugal forces. As a result, during a driving mode, the lubricant 162 in the sump 160 is gradually lowered from the first lubricant level 164 to a lower lubricant level 168, which can also be referred to as the third lubricant level. At the same time, the second gear segment 242 thus lengthens by a significant length, namely to a third gear segment 244, i.e. to this gear segment 244 that must be traveled until lubricant 162 from the sump 160 arrives at the second gear 50. In other words, when the lubricant level 168 is lowered, the time taken until lubricant 162 is drawn up to the second gear 50 is extended.

[0184] Meanwhile, the fourth gear 75 draws lubricant 162 upward from a gear lubrication pan 208 by means of second splash teeth, such as the second splash tooth 232, with a direction of rotation identical to the first gear 77 with its direction of rotation 260. The direction of rotation 260 refers to one of two possible directions of rotation of the gear 77. The lubricant 162 from the gear lubrication pan 208 is at least partially transferred to the third gear 49. In a rest state of the dual transmission 1, the gear lubrication pan 208 has a second lubricant level 166, the height of which is limited by a flow-off barrier 224 of the gear lubrication pan 208. The second lubricant level 166 can be lowered to another, lower lubricant level 166.sup.II by the delay means 180.sup.II, preferably in the form of an electromechanically closable shutter opening in a gear lubrication wall 208. The gear lubrication pan 208 and the oil collection pan 234 that adjoins it in a vertical direction are formed as regions of the oil-guiding wall 226. The oil collection pan 234 is located in an angular range around the input shaft 35 and around the gear 75 arranged on the input shaft 35 (see FIG. 3), catches peripheral oil splashes, i.e. oil splashes not directed toward a gear, and routes said oil into the gear lubrication pan 208. Transmission oil can be discharged from the gear lubrication wall 208 into the collection chamber 204 in a controlled manner. As the input shaft 35 rotates, energy losses caused by splashing can thus be kept low. The delay means 180.sup.II is preferably closed when the transmission is at a standstill. Such a two-level transmission oil system 164, 166, 166.sup.II, 168, in particular a dual-level transmission oil system, of a single transmission 17 enables rapid lubrication of the stepped gear 79, for example at the time of transmission start-up, from two different directions, i.e. from a drive side or a side of the input shaft 25 and from an output side or a side of the output shaft 39.

[0185] By means of centrifugal forces, excess lubricant 162 that is drawn upward to the stepped gear 79 is supplied at least partially in droplet form to a gravity run-off path 190. The gravity run-off path 190 extends along an inner side 104.sup.I of the transmission case 31. Located between the inner side 104.sup.I and the oil-guiding wall 226, which partially surrounds the gears 49, 75 and 77, is a system consisting of a plurality of chambers arranged one after the other in the direction of gravity, i.e. a chamber system 200 which has a plurality of delay means, such as the delay means 180, which is a wall constriction, or the delay means 180.sup.I, which is a flow valve 188, for a lubricant run-off. The oil-guiding wall 226 has the shape of a scraper at its upper end, so that lubricant 162 can be stripped by the scraper from the gear 49 moving past. A first chamber is the drip chamber 202, in which lubricant droplets are collected. The drip chamber forms an uppermost chamber in a vertical sequence of chambers. Collected lubricant is separated from abraded metal material by a separating magnet 228 at the bottom of the drip chamber. Lubricant that has thus been cleaned is supplied in droplet form, via a nozzle 182 in conjunction with a shutter 184, to the collection chamber 204. The expression “in droplet form” also encompasses the situation where the oil may be supplied as a narrow flow; no particular droplet shape of the lubricant is required. The separating magnet 228 prevents clogging of the nozzle 182. The shutter 184 prevents oil droplets from passing directly downward from the inner side 104.sup.I. Droplets from the nozzle 182 enter the collection chamber 204. A reservoir of lubricant can accumulate in the collection chamber 204. The collection chamber as a middle chamber can thus also be referred to as a first reservoir chamber. The collection chamber 204 has a wall portion which can be referred to as a discharge-side part 222 and forms a flow-off choke 186. From the collection chamber 204, the lubricant 162 enters the reservoir chamber 206. The reservoir chamber 206, which can also be referred to as the second reservoir chamber 206, is a lowermost chamber of the multi-chamber system 200. The reservoir chamber 206 is equipped with the flow valve 188 in its discharge-side part 222.sup.I. A return flow of lubricant 162 into the sump 160 can be at least intermittently blocked by the flow valve 188, which forms a delay means 180.sup.I. The delay means 180, 180.sup.I thus described ensure that the third lubricant level 168 has a height sufficient for lubricating the dual transmission 1, while ensuring that energy losses caused by a stirring of the first gear 77 in the sump 160 are kept as low as possible. By way of the delay means 180.sup.I, i.e. by way of the flow valve 188, the second lubricant level 166.sup.I in the reservoir chamber 206 may decrease toward the lubricant level 168, provided that the lubricant level 168 is below the second lubricant level 166.sup.I. Thanks to the delay means 180.sup.I, an equalization of the lubricant level takes place between the lubricant level 168 present in the sump 160 and the second lubricant level 166.sup.I present in the reservoir chamber 206. The first lubricant level 164 encourages a rapid, pump-free distribution of oil when starting up the dual transmission 1. It is thus possible to equip the teeth 77, 50, 49, 75 with a surface lubrication 220 by a lubricant 162.

[0186] With reference to FIGS. 5 to 8, which will be discussed jointly, a spectacles-type bearing bracket 330 and the installation thereof in a transmission 1.sup.II (see FIG. 8) will now be described:

[0187] FIG. 5 shows one possible embodiment of a spectacles-type bearing bracket 330, which can be installed as a component in a dual transmission 1.sup.II (for example according to FIG. 8 or FIG. 3). The spectacles-type bearing bracket 330 (see FIG. 3) has a first narrow side 354 opposite a second narrow side 356. The narrow sides 354, 356 are adjoined by a first plate long side 358 and a second plate long side 360 when moving round the spectacles-type bearing bracket 330 along an edge 418. The sides 354, 356, 358, 360 form curved boundaries of the web plate 352. They form part of the spectacles-type bearing bracket 330 in the manner of a web plate edge. The web plate 352 has in its rounded corner regions a first pin receptacle 424, a second pin receptacle 426, a third pin receptacle 428, and a fourth pin receptacle 430. Two opposite pin receptacles arranged diagonally opposite each other in relation to a flat extension of the spectacles-type bearing bracket 330, namely the first pin receptacle 424 and the third pin receptacle 428 or the second pin receptacle 426 and the fourth pin receptacle 430, are supported in each case diagonally opposite each other as an attachment structure that is thicker than the web plate 352. The attachment structure is part of a stiffening of a plate plane of the web plate 352.

[0188] The spectacles-type bearing bracket 330 has a circular hole structure 344 approximately in the center between the pin receptacles 424, 426, 428, 430. The hole structure 344 is provided as a continuous opening with a stepped wall through the web plate 352. The hole structure 344 defines an orientation of shafts to be attached, such as the output shafts 37, 39 shown in FIG. 3. An output direction 338 in the dual transmission (see dual transmission 1 of FIG. 3) is thus specified. The hole structure 344 together with the webs 400, 400.sup.I, 402, 404, 406 protruding from the spectacles-type bearing bracket 330 (see also FIG. 6 and FIG. 7) form a single-hole support structure 342. The single-hole support structure 342 has bosses and overhangs formed in one piece with the web plate 352. The single-hole support structure 342 has a plurality of hole structure supports, such as the hole structure support 346, which each extend radially away from the hole structure 344. A support collar 348 of the hole structure supports 346 ensures particularly good stabilization of the spectacles-type bearing bracket 330 in a tangential direction around the hole structure 344.

[0189] As a further measure to mechanically stabilize the spectacles-type bearing bracket 330, the web plate 352 is strutted by a plurality of webs, such as the first web 400. The webs 400 can also be referred to as web plate thickenings.

[0190] Located in the hole structure 344, in particular lined up next to each other in a ring-shaped arrangement, is a plurality of identical barrel rolling elements, for example the barrel rolling element 372.

[0191] The section line A-A in FIG. 5 shows where the spectacles-type bearing bracket 330 according to FIG. 5 is to be cut in order to achieve the cross-sectional view show in FIG. 6.

[0192] Inter alia, it can be seen in FIG. 6 that the spectacles-type bearing bracket 330 is largely mirror-symmetrical and has a first spectacles-type bearing bracket side 332 and a second spectacles-type bearing bracket side 334, which are defined with reference to a mirror surface 336. Run-off bores (not shown), in particular for oil, may be provided on the spectacles-type bearing bracket 330, these being arranged in a manner differing from the mirror symmetry. In the figure shown, the mirror surface 336 extends perpendicularly out of the plane of the drawing. A first barrel bearing 362 and a second barrel bearing 364 are arranged in mirrored positions (with the mirror axis at the mirror surface 336). A barrel bearing gap 368 is provided between the barrel bearings 362, 364, said gap forming an intermediate space 462. In the intermediate space 462, one end of each of the output shafts (see output shafts 37 and 39 in FIG. 3) can be placed into the barrel bearings 362, 364 at a distance from each other and thus without rubbing against each other. The intermediate space 462 can also be referred to as the lubrication space 462 for the barrel bearings 362, 364.

[0193] As the bearing lubrication chamber 450, the lubrication space 462 is at the same time part of a multi-chamber system 200.sup.I which serves to return transmission oil to the sump (see sump 160 in FIG. 3) in a delayed manner. Transmission oil located in the bearing lubrication chamber 450 flows into the barrel bearings 362, 364 and, from the barrel bearings 362, 364, returns to the sump in a delayed manner after being circulated through the bearing circuit. Transmission oil is routed from two reservoir chambers 448, 448.sup.I, via respectively connected nozzles with lubrication openings, such as the nozzle 440 with the opening 442, which serve as delay means 440, 442, into the bearing lubrication chamber 450. In each of the reservoir chambers 448, 448.sup.I, a lubrication reservoir 446, 446.sup.I is formed by a constant inflow from collection chambers 416, 416.sup.I, arranged upstream in the flow direction. The two lubrication reservoirs 446, 446.sup.I are regarded as a joint reservoir because the two barrel bearings 362, 364 are continuously supplied with transmission oil therefrom. Oil guides 412, 414 are provided on the spectacles-type bearing bracket 330. The oil guides 412, 414 are arranged as inclined surfaces, the lowermost end of which merges into a collection chamber 416, 416.sup.I. The oil guides 412, 414 are shaped in the manner of a spatula or scraper. They are two blade-like structures with oil-guiding surfaces. Splash oil or oil droplets supplied to the collection chambers 416, 416.sup.I via a predefined flow-off path (without a reference sign) accumulate on the oil guides 412, 414. The oil guides 412, 414 can also be regarded as part of the collection chambers 416, 416.sup.I. The splash oil has been formed in particular by gears splashing in the sump or in a lubrication pan (see gear 77 and sump 160 or gear 75 and gear lubrication pan 208 in FIG. 3).

[0194] The barrel bearings 362, 364 are of identical construction, i.e. they each have barrel rolling elements, such as the barrel rolling element 372, which are guided in an outer barrel bearing ring, such as the barrel bearing ring 370. The outer barrel bearing ring 370 is held in the spectacles-type bearing bracket 330 by a retaining clip 366. The barrel bearings 362, 364 can thus be separated from the spectacles-type bearing bracket 330 for maintenance after long-term operation, for example if bearing wear has occurred. This facilitates maintenance work, such as replacement or exchange of the bearings 362, 364.

[0195] A respective contact surface 436 of the pin receptacles, such as the first pin receptacle 424 or the second pin receptacle 426, is located in an intermediate region between an internal diameter 434 and an external diameter 432. For both pin receptacles 424, 426, mention can also be made of a contact surface, more precisely the contact surface 436, at which the pin receptacles 424, 426 end. A pin receptacle can also be referred to as a receptacle for a pin. A pin receptacle extension 438 is assigned to the contact surfaces, such as the contact surface 436, as a gap. A pin receptacle extension 438 is larger than the barrel bearing gap 368, which is defined by the outer barrel bearing rings, such as by the barrel bearing ring 370. The pin receptacle extension 438 spaces apart a pair of contact surfaces and is preferably larger than the external diameter 432. Pin receptacles, such as the pin receptacles 424, 426, are suitable for receiving a pin having a pin diameter that is only slightly smaller than the internal diameter 434, so that the pin can be received with as little play as possible in the opening having the internal diameter 434. A size of the external diameter 432 secures the pin receptacles 424, 226 against breaking free. The external diameter is preferably at least twice the internal diameter 434. All the pin receptacles 424, 426 may be of equal size.

[0196] Webs, such as the web 400.sup.I, form a splined connection between the contact surfaces, such as the contact surface 436, and the hole structure 344. The web 400.sup.I is tapered toward the first pin receptacle 424. The webs, such as the web 400.sup.I, stiffen the spectacles-type bearing bracket 330 in a manner that is efficient in terms of material and weight, in particular against torsion.

[0197] To continue the description of the multi-chamber system 200.sup.I according to FIG. 6, a first oil guide 412 on the first side 332 of the spectacles-type bearing bracket and a second oil guide 414 on the second side 334 of the spectacles-type bearing bracket are located opposite the first pin receptacle 424 when moving from the first pin receptacle 424 in a diagonal direction toward an opposite side of the hole structure 344. The oil guides 412, 414 are designed in a plate-like manner and have a larger extension toward the sides 332, 334 of the spectacles-type bearing bracket 330 than the webs, such as the web 400.sup.I for example. The oil guides 412, 414 serve to collect oil that has been splashed upward by rotating gears. The oil is supplied via the oil-guiding surfaces 412, 414, which can also be referred to as oil guides, to a lubrication reservoir 446, 446.sup.I. The inflow takes place in a manner driven by gravity, unless a driving acceleration causes the effect to be different. From the lubrication reservoir 446, 446.sup.I, oil is discharged in an axial direction 444, or with a direction component along the axial direction 444, from at least one lubrication nozzle, such as the lubrication nozzle 440, via the lubrication opening 442 thereof. Aided by a nozzle angle position relative to the axial direction 444, oil passes to both sides of the barrel bearings 362, 364, i.e. transversely to the axial direction 444. Rotating surfaces (for example at ends of the output shafts 37, 39 in FIG. 3), which bound the intermediate space, additionally encourage the distribution of oil onto the barrel bearings 362, 364. The lubrication opening 442 is selected to be so large, preferably in a manner tailored to a viscosity of the transmission oil, that a lubrication can take place as reliably and evenly as possible, for example as droplets or as a narrow flow.

[0198] FIG. 7 shows a perspective view of the spectacles-type bearing bracket 330, looking toward the first side 332 of the spectacles-type bearing bracket. The second side 334 of the spectacles-type bearing bracket is structured identically to the first side 332 of the spectacles-type bearing bracket. By looking at FIG. 3, it can easily be deduced that it can also be said that the first side 332 of the spectacles-type bearing bracket can be used to mount at least one component of a first sub-transmission 15 and the second side 334 of the spectacles-type bearing bracket can be used to mount at least one component of a second sub-transmission 17.

[0199] As can also be seen from FIG. 7, located on the web plate 352 of the spectacles-type bearing bracket 330 is a first oil guide 412, which is assigned to the first side 332 of the spectacles-type bearing bracket, and a second oil guide 414, which is assigned to the second side 334 of the spectacles-type bearing bracket. The oil guides 412, 414 can also be referred to as protruding reinforcements of the web plate 352. The oil guides 412, 414 together with the web plate 352 form a pocket-like oil collection region 416. The oil guides 412, 414 extend from the vicinity of a pin receptacle, namely the third pin receptacle 428, to the respective collection chamber, such as the collection chamber 416. The oil guides 412, 414 and the collection chambers 416, as well as the bearing lubrication chamber 450, belong to a multi-chamber system 200.sup.I, which is advantageous for passive oil guidance in a transmission or transmission case (see for example transmission 1 or sub-transmission 17 and transmission case 31 in FIG. 3).

[0200] As a further interesting aspect, it can be mentioned with regard to a structural reinforcement of the web plate 352 that the plate-like oil guides 412, 414 projecting perpendicularly from the web plate 352 are a stabilizing structural element of the single-hole support structure 342 and thus of the spectacles-type bearing bracket. Other elements that form stabilizing structures are hole structure supports, such as the hole structure support 346.sup.I, webs, such as the first web 400, the second web 402, the third web 404, the fourth web 406, as well as a first web intersection 408 and a second web intersection 410. Web intersections, such as the first web intersection 408 and the second web intersection 410, are formed in each case of two or three intersecting webs. Stabilizing structural elements serve to dissipate forces, such as deformation forces or lever forces, which act on the hole structure 344 in an operating state of a transmission, to the pin receptacles, such as the first pin receptacle 424, the second pin receptacle 426, the third pin receptacle 428 or the fourth pin receptacle 430, in a manner that is spatially distributed as evenly as possible. The aforementioned forces or structural loads that occur during operation are transmitted to the case (see sub-case 331 in FIG. 8) by dissipation via the spectacles-type bearing bracket 330 (and thus the load limit for plastic deformations is observed). Further stabilizing structural elements of the single-hole support structure 342 are edge webs arranged at the edge region 418, such as a first edge web 420 and a second edge web 422, as well as the regions of the web plate 352 arranged between or next to the webs 402, 404, 406, 408, 410.

[0201] The view shown in FIG. 8 illustrates one possible way of installing the spectacles-type bearing bracket 330 in a sub-case 331 for a first single transmission, such as for example the single transmission 15 in FIG. 3. A complete transmission 1.sup.II can thus be assembled, which is suitable for a motor vehicle 500 or 500.sup.I according to FIG. 1 or FIG. 2. A rolling bearing 369 for bearing an output shaft sleeve in a rotatable manner, such as the output shaft sleeve 337, but which is arranged at an end of the output shaft 39.sup.I toward the sub-case 331 that is hidden in this perspective, is held in the sub-case 331 by a retaining clip 394. At an opposite end region of the output shaft 39.sup.I, at which the output shaft sleeve 337 is provided, the output shaft 39.sup.I (see also the output shafts 37, 39 shown in FIG. 3) is borne in the spectacles-type bearing bracket 330 via a floating bearing 380 together with an associated wheel bearing surface of the output shaft 39.sup.I. The retaining clip 366.sup.I to be installed on the spectacles-type bearing bracket 330 in order to axially secure the barrel bearing 364 has been illustrated in an exposed manner for better clarity.

[0202] It can also be said that the single-hole support structure 342 forms part of the floating bearing 380.

[0203] The pin receptacles, such as the first pin receptacle 424, of the spectacles-type bearing bracket 330 form a mounting frame 340 for the floating bearing 380. The mounting frame 340 can be attached to the pin holders, such as the pin holder 460, a first pin holder, by the pin receptacles, such as the pin receptacle 424. The third pin receptacle 428 is located diagonally opposite the first pin receptacle 424 on the spectacles-type bearing bracket 330 and is associated with a pin holder 460.sup.I which, depending on the manner of counting, can also be referred to as the third pin holder. The pin holders 460, 460.sup.I each have support surfaces 458, 458.sup.I. The contact surface 436 (see FIG. 6) and the support surface 458 (see FIG. 8) are associated with each other. An axial position of the spectacles-type bearing bracket 330 along the half-axles 520, 522 is thus defined (see FIG. 3). To attach the spectacles-type bearing bracket 330, a first pin 382 can be passed through the first pin receptacle 424. In the installed state of the spectacles-type bearing bracket 330, the first pin 382 is firmly seated in the pin holder 460. Accordingly, the spectacles-type bearing bracket 330 is held by at least three pins 382, 384, 386. In the illustration shown in FIG. 8, a second pin 384 and a third pin 386 can be seen. A fourth pin, which is also present, is concealed. The pins 382, 384, 386 define a radial position of the spectacles-type bearing bracket 330 transversely to the half-axles 520, 522, such as the third position 23 (see FIG. 3). It can be said that the pins 382, 384, 386 form an assembly system or an assembly array for an outer bearing 374 of the half-axles 520, 522 (see FIG. 1 or FIG. 2), in particular created by the spectacles-type bearing bracket 330. The pins 382, 384, 386 have a greater length than the pin receptacle extension 438 in FIG. 6. In other words, the pins 382, 384, 386 with their respective first pin ends are held in a hole of a corresponding pin holder, such as the pin holders 460, 460.sup.I, which form part of the (sub-)case 331. Once the spectacles-type bearing bracket 330 has been inserted in the first sub-case 331, this structural unit consisting of the spectacles-type bearing bracket 330 and the sub-case 331 is latched together, so to speak, and can be brought into an angle position, without slipping, for further assembly purposes. This facilitates assembly of the sub-transmission, such as the sub-transmission 15 in FIG. 3. The four pins (see pins 382, 384, 386) are additionally held with their second ends on a second sub-case (not shown), which serves to accommodate a second sub-transmission, such as the sub-transmission 17 in FIG. 3, to construct a dual transmission 1.sup.I. Owing to its preferred design or the parallel arrangement of shafts, the dual transmission 1.sup.II can also be referred to as a longitudinal transmission in relation to a vehicle longitudinal axis 524 (see FIG. 1 or FIG. 2).

[0204] The design possibilities shown in the individual figures can also be combined with each other in any form.

[0205] For instance, it is possible to make the partition walls 73, 73.sup.I longer or shorter and yet still leave one complete, contiguous oil space in the transmission case 31.

[0206] Of course, it is also possible for the transmission 1, which according to FIG. 1 is arranged with its center of gravity in front of the rear axle 518, to be installed in a vehicle in such a way that it is located with its center of gravity behind the rear axle 518, as shown in FIG. 2 using the example of the transmission 1.sup.I. The transmission 1.sup.II, which is shown in FIG. 8 not with all the components because FIG. 8 deals in particular with the arrangement of the spectacles-type bearing bracket and of the output in the transmission, can be supplemented with other components, such as a dual input shaft 32 and components of the stationary middle axle 45, according to FIG. 3 or according to FIG. 4, to form a complete transmission, and can be closed by a second case shell.

[0207] The central axle 45, which is shown as hollow in FIG. 3, may be designed in a solid fashion. The axles 33, 35, 37, 39 may also be hollow.

[0208] A person skilled in the art understands that the rear-axle drive variant of a motor vehicle 500 of a vehicle with front-axle drive, which is shown by way of example in FIG. 1 or FIG. 2, can also be accordingly reconfigured for a front-axle drive variant. In this case, not only does the steering movement from the steering wheel 514 act, by way of the steering linkage 516, on the road wheels 510, 512 and the angle position thereof, but also the powertrain 3 opens into the road wheels 510, 512.

[0209] The invention can also be presented as follows. A transmission 1, for example for a duo electric machine powertrain, has a sump 160, into which at least a first gear 77 dips. Adjacent to a multi-chamber system 200, a gear stage 55 is formed by a first gear 77 and a second gear 49, 35 50, 79. The second gear 49, 50, 79 performs the function of a centrifugal lubricating film separator gear for separating oil from the surface of the gear 49, 50, 79, by using a centrifugal force, and delivering said oil to the multi-chamber system 200. The multi-chamber system 200 acts as a flow path which continuously delivers a lubricant 162 and by way of which lubricant can enter the sump 160 through a delay means 180, 180.sup.I, 180.sup.II. Such a system can also be part of a spectacles-type bearing bracket. In the case of such a multi-chamber system 200, lubricant 162 that is splashed by the second gear 49, 50, 79 is received in one chamber 202, 204 of the multi-chamber system 200, is stored in a further chamber 204, 206, and is recirculated to the sump 160 only via a delay means 180, 180.sup.I, 180.sup.II.

LIST OF REFERENCE SIGNS

[0210] 1, 1.sup.I, 1.sup.II dual transmission or twin transmission, designed as a spur gear transmission [0211] 3, 3.sup.I powertrain, in particular duo electric machine powertrain [0212] 5, 5.sup.II first electric machine [0213] 5.sup.I first drive torque [0214] 7, 7.sup.II second electric machine [0215] 7.sup.I second drive torque [0216] 9 energy store, in particular electrical accumulator [0217] 11 first electrical lead [0218] 13 second electrical lead [0219] 15 single transmission, in particular first single transmission or sub-transmission [0220] 17 single transmission, in particular second single transmission or sub-transmission [0221] 19 position, first [0222] 21 position, second, middle [0223] 23 position, third [0224] 25 gear center, in particular first gear center [0225] 27 gear center, in particular second gear center [0226] 29 gear center, in particular third gear center [0227] 31 transmission case [0228] 32 dual input shaft [0229] 33 input shaft [0230] 35 input shaft [0231] 37 output shaft [0232] 39, 39.sup.I output shaft [0233] 41 case wall [0234] 43 case wall [0235] 44 axle, in particular of the input shafts [0236] 45 axle, middle [0237] 49, 49.sup.I third gear, in particular driven spur gear in traction mode [0238] 50, 50.sup.I second gear, in particular output spur gear in traction mode [0239] 51 case bottom [0240] 53 stage, first, in particular gear stage with ratio [0241] 55 stage, second, in particular gear stage with ratio [0242] 57, 57.sup.I tooth [0243] 59, 59.sup.I tooth [0244] 61 needle bearing [0245] 63 needle bearing [0246] 65 rolling bearing [0247] 67 rolling bearing [0248] 69 rolling bearing [0249] 71 rolling bearing [0250] 73, 73.sup.I case wall, in particular case partition wall, such as a spectacles-type bearing bracket [0251] 75, 75.sup.I fourth gear, in particular of the input shaft [0252] 77, 77.sup.I first gear, in particular spur gear of the output shaft [0253] 79 stepped gear [0254] 102 inner side, first inner side [0255] 104, 104.sup.I inner side, second inner side [0256] 106 width [0257] 108 internal volume [0258] 110 center, in particular of the case, or central region of the case [0259] 114 gear axle, in particular stationary gear axle [0260] 116 sleeve [0261] 118, 118.sup.I, 118.sup.II bore [0262] 120 case longitudinal direction [0263] 130 breather cap or breather element [0264] 134 first portion, in particular thicker portion [0265] 136 second portion, in particular narrower portion [0266] 160 sump [0267] 162 lubricant [0268] 164 first lubricant level, in particular of the sump [0269] 166, 166.sup.I, 166.sup.II further lubricant level, in particular second lubricant level [0270] 168 third lubricant level, in particular of the sump [0271] 180, 180.sup.I, 180.sup.II delay means [0272] 182 nozzle [0273] 184 shutter [0274] 186 choke [0275] 188 flow valve [0276] 190 gravity run-off path [0277] 200 chamber system, in particular multi-chamber system [0278] 202 drip chamber, in particular uppermost chamber [0279] 204, 204.sup.I collection chamber, in particular first reservoir-forming chamber [0280] 206 reservoir chamber, in particular lowermost chamber [0281] 208 gear lubrication pan, in particular gear lubrication chamber [0282] 210 wall support, in particular bearing support [0283] 212 aperture, in particular equalizing flow opening [0284] 220 surface lubrication [0285] 222, 222.sup.I discharge-side part [0286] 224 flow-off barrier [0287] 226 oil-guiding wall, in particular in the form of an oil scraper [0288] 228 separating magnet [0289] 230 first splash tooth [0290] 232 second splash tooth [0291] 234 oil collection pan [0292] 240 first gear segment [0293] 242 second gear segment [0294] 244 third gear segment [0295] 250 running surface of a gear [0296] 260 direction of rotation of gear [0297] 330 spectacles-type bearing bracket [0298] 331 sub-case of the transmission [0299] 332 first side of the spectacles-type bearing bracket [0300] 334 second side of the spectacles-type bearing bracket [0301] 336 mirror surface [0302] 337 output shaft sleeve [0303] 338 output direction [0304] 340 mounting frame [0305] 342 single-hole support structure [0306] 344 hole structure [0307] 346, 346.sup.I hole structure support [0308] 348 support collar [0309] 352 web plate [0310] 354 first narrow side of plate 356 second narrow side of plate [0311] 358 first long side of plate [0312] 360 second long side of plate [0313] 362 first barrel bearing, in particular rolling-element bearing [0314] 364 second barrel bearing, in particular rolling-element bearing [0315] 366, 366.sup.I retaining clip [0316] 368 barrel bearing gap, in particular gap between two rolling-element bearings [0317] 369 rolling bearing [0318] 370 outer barrel bearing ring, in particular running surface [0319] 372 barrel rolling elements [0320] 374 outer bearing [0321] 380 floating bearing, in particular wheel bearing surface [0322] 382 first pin [0323] 384 second pin [0324] 386 third pin [0325] 394 retaining clip [0326] 396 gear, in particular third gear [0327] 400, 400.sup.I first web [0328] 402 second web [0329] 404 third web [0330] 406 fourth web [0331] 408 first web intersection [0332] 410 second web intersection [0333] 412 first oil guide, in particular oil supply surface [0334] 414 second oil guide, in particular oil supply surface [0335] 416, 416.sup.I oil collection region, in particular collection chamber for oil droplets [0336] 418 edge of spectacles-type bearing bracket [0337] 420 first edge web [0338] 422 second edge web [0339] 424 first pin receptacle [0340] 426 second pin receptacle [0341] 428 third pin receptacle [0342] 430 fourth pin receptacle [0343] 432 external diameter of the pin receptacle [0344] 434 internal diameter of the pin receptacle [0345] 436 contact surface [0346] 438 pin receptacle extension [0347] 440 delay means, in particular lubrication nozzle [0348] 442 delay means, in particular lubrication opening such as a shutter opening [0349] 444 axial direction of the nozzle [0350] 446, 446.sup.I lubrication reservoir [0351] 448, 448.sup.I reservoir chamber [0352] 450 bearing lubrication chamber [0353] 458, 458.sup.I support surface [0354] 460, 460.sup.I pin holder, in particular first pin holder [0355] 462 intermediate space [0356] 500, 500.sup.I motor vehicle [0357] 502 direction of travel [0358] 504 vehicle floor [0359] 506 first road wheel [0360] 508 second road wheel [0361] 510 third road wheel [0362] 512 fourth road wheel [0363] 514 steering wheel [0364] 516 steering linkage [0365] 518, 518.sup.I vehicle rear axle [0366] 520 first half-axle [0367] 522 second half-axle [0368] 524 vehicle longitudinal axis [0369] 526 rear compartment [0370] 528 trunk region [0371] 532 coupling [0372] 534 coupling [0373] A section plane [0374] B reference plane [0375] G straight line [0376] M region, in particular middle region [0377] d.sub.1 diameter of a gear 49, 49.sup.I [0378] d.sub.2 diameter of a gear 50, 50.sup.I [0379] β.sub.1 angle of inclination [0380] β.sub.2 angle of inclination