Motor vehicle transmission with a power take-off

Abstract

A motor vehicle transmission including an input shaft (AN), an output shaft (AB), a power take-off (1) and a hydraulic pump (2). The hydraulic pump (2) serves to supply the motor vehicle transmission with hydrodynamic working pressure. The power take-off (1) has a power take-off gearwheel (1A). The power take-off gearwheel (1A) is connected to the hydraulic pump (2) in order drive the hydraulic pump (2).

Claims

1. A motor vehicle transmission comprising: an input shaft, an output shaft, a power take-off, a hydraulic pump, a transmission housing having a first intermediate wall that separates an interior of the transmission housing into at least a power take-off space and a transmission space, the hydraulic pump serving to supply the motor vehicle transmission with hydraulic working pressure, the power take-off having a power take-off gearwheel, and the power take-off gearwheel being connected to the hydraulic pump in order to drive the hydraulic pump, and the hydraulic pump being fixed to the first intermediate wall such that the hydraulic pump and the power take-off gearwheel are arranged within the transmission housing in the power take-off space.

2. The motor vehicle transmission according to claim 1, wherein the power take-off gearwheel has a first set of teeth that drive the power take-off and a second set of teeth that drive the hydraulic pump.

3. The motor vehicle transmission according to claim 1, wherein the power take-off gearwheel has a common set of teeth that drive the power take-off and the hydraulic pump.

4. The motor vehicle transmission according to claim 1, wherein the power take-off gearwheel is rotatably supported by the first intermediate wall.

5. The motor vehicle transmission according to claim 4, wherein the first intermediate wall has a tubular projection, and the power take-off gearwheel is rotatably supported on the projection by a radial bearing arranged on the projection.

6. The motor vehicle transmission according to claim 4, wherein the first intermediate wall supports the power take-off gearwheel in an axial direction toward the first intermediate wall.

7. The motor vehicle transmission according to claim 6, wherein either a thrust washer or an axial roller bearing is arranged axially between the first intermediate wall and the power take-off gearwheel.

8. The motor vehicle transmission according to claim 4, further comprising a second intermediate wall, the second intermediate wall axially supports the power take-off gearwheel in an axial direction toward the second intermediate wall.

9. The motor vehicle transmission according to claim 8, wherein either a thrust washer or an axial roller bearing is axially arranged between the second intermediate wall and the power take-off gearwheel.

10. The motor vehicle transmission according to claim 8, wherein the input shaft defines an axis, and the first intermediate wall and the second intermediate wall each has a radially outer end that contacts the transmission housing, the first and the second intermediate walls extend radially inward from the transmission housing and axially divide the interior of the transmission housing into the transmission space, the power take-off space, and a clutch bell space such that the power take-off space is axially located between the clutch bell space and the transmission space, gearwheels for force-transmission between the input shaft and the output shaft are arranged within the transmission space, a force-transmission means of the power take-off and the power take-off gearwheel are arranged within the power take-off space, a starting clutch is arranged within the clutch bell space which is axially located on a drive input side of the transmission housing, the first intermediate wall axially spatially separates the transmission space from the power take-off space, and the second intermediate wall axially spatially separates the clutch bell space from the power take-off space.

11. The motor vehicle transmission according to claim 10, wherein the starting clutch is a torque converter of the motor vehicle transmission.

12. The motor vehicle transmission according to claim 1, further comprising a hydrodynamic torque converter which is axially located on a drive input side of the transmission, the drive input side being adjacent an axial side of the power take-off space opposite the first intermediate wall, the torque converter comprises a pump wheel and a turbine wheel, the turbine wheel is connected to the input shaft in order to drive the input shaft, and the pump wheel is connected to the power take-off gearwheel in order to drive the power take-off gearwheel.

13. A motor vehicle transmission comprising: transmission housing having an interior area in which an input shaft and an output shaft extend along an axis; first and second intermediate walls that contact an inside of the transmission housing and extend radially inward therefrom and spatially divide the interior area of the transmission housing axially into a torque converter space, a power take-off space and a transmission space; a hydrodynamic torque converter being located within the torque converter space on an input side of the transmission, and the second intermediate wall axially separating the torque converter space from the power take-off space; transmission shifting elements, transmission gearwheels and transmission shafts being located within the transmission space on an output side of the transmission, the first intermediate wall axially separating the transmission space from the power take-off space, and at least the transmission shifting element being actuatable for selectively engaging various transmission gear ratios; a power take-off and a hydraulic pump being located within the power take-off space which axially extends from the first intermediate wall to the second intermediate wall, the hydraulic pump being rotationally drivable to supply hydraulic working pressure to the transmission shifting elements for actuation thereof; the power take-off having a power take-off gearwheel which is rotationally supported by a first axial side of the first intermediate wall within the power take-off space, and the power take-off gearwheel meshes with an intermediate gearwheel of the power take-off to rotationally drive the power take-off; the hydraulic pump being fixed to the first axial side of the first intermediate wall within the power take-off space, and the hydraulic pump is connected to and rotationally driven by the power take-off gearwheel.

14. The motor vehicle transmission according to claim 13, wherein the power take-off gearwheel has first and second sets of teeth that are located within the power take-off space, the first set of teeth meshing with the intermediate gearwheel of the power take-off to rotationally drive the power take-off, and the second set of teeth being connected to the hydraulic pump to rotationally drive the hydraulic pump.

15. The motor vehicle transmission according to claim 13, wherein the power take-off gearwheel has first and second sets of teeth that are located within the power take-off space and axially spaced from one another by a gap, the first set of teeth meshing with the intermediate gearwheel of the power take-off to rotationally drive the power take-off, and the second set of teeth being connected to the hydraulic pump to rotationally drive the hydraulic pump.

16. The motor vehicle transmission according to claim 15, wherein the hydraulic pump has chain wheel which is fixed to a rotatable pump shaft, the second set of teeth of the power take-off gearwheel are connected, via a link chain, to the chain wheel of the hydraulic pump to rotationally drive the hydraulic pump, and the first set of teeth of the power take-off gearwheel directly mesh with the intermediate gearwheel of the power take-off to rotationally drive the power take-off.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Below, the invention is explained in greater detail with reference to figures from which further preferred embodiments of the invention can emerge. These show, in each case schematically:

(2) FIG. 1: A longitudinal section through a motor vehicle transmission,

(3) FIG. 2: Part of a more detailed longitudinal section through a motor vehicle transmission.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

(4) In the figures, the same or at least functionally equivalent components are given the same indexes.

(5) The motor vehicle transmission shown in each figure is in the form of a multi-step transmission. Thus, it has a plurality of gear ratios that can be engaged.

(6) In the upper part of the transmission shown in FIG. 1, a power take-off 1 of the transmission with the associated power take-off gearwheel 1A is shown, as an example. The lower part shows as an example the mechanical coupling of a hydraulic pump 2 of the transmission with a torque converter 3 arranged on the input side of the transmission.

(7) The transmission has a transmission housing 4. Inside the transmission housing 4 the spaces 4A, 4B, 4C spatially separated by intermediate walls 5, 6 are formed. These are an inside space 4A of a clutch bell housing of the transmission, within which the converter 3 is arranged; a power take-off space 4B in which the force-transmitting means of the power take-off 1 are arranged; and an inside space 4C of the transmission in which the essential elements for the various gear ratio steps of the motor vehicle transmission are arranged, i.e. the actual transmission itself. These spaces 4A, 4B, 4C are spatially separated from one another by the intermediate walls 5, 6.

(8) The torque converter 3 is of conventional design. It consists essentially of the pump wheel 3A on the drive input side and the turbine wheel 3B driven hydrodynamically by it on the drive output side. In addition a stator wheel 3C can be provided. Between the pump wheel 3A and the turbine wheel 3B a bridging clutch 3D may be provided. The pump wheel 3B is coupled to a drive motor (not shown) in order to be driven by it. This is indicated by the arrow shown adjacent thereto. Thus, the rotational speed of the drive motor corresponds to the rotational speed of the pump wheel 3B. The drive motor and thus also the pump wheel 3B have a specified, usual rotational direction envisaged.

(9) The pump wheel 3A is mechanically coupled to the hydraulic pump 2, so that the pump 2 is powered by the pump wheel 3A. This coupling takes place indirectly by way of the power take-off gearwheel 1A. The force transfer from the power take-off gearwheel 1A to the hydraulic pump 2 then takes place by gearwheel transmission and/or chain transmission. For example, FIG. 1 shows force transfer by way of a link chain 2A. The hydraulic pump 2 is arranged within the intermediate wall 5. For that purpose the associated pump housing is let into it or forms part of the intermediate wall 5. Thus, the intermediate wall supports the hydraulic pump 2.

(10) The turbine wheel 3B is coupled to an input shaft AN of the transmission in order to drive the input shaft AN. Thus, the rotational speed of the turbine wheel 3B corresponds to the rotational speed of the input shaft AN. The input shaft AN extends through the power take-off space 4B into the inside space 4C of the transmission. In the power take-off space 4B the power take-off gearwheel 1A is mounted to rotate coaxially with the input shaft AN.

(11) The power take-off gearwheel 1A is drive-coupled to a power take-off shaft 1D. This can be done, for example, by gearwheel transfer and/or by a chain drive. As an example FIG. 1 shows a gearwheel transfer mode by way of an intermediate wheel 1B. The power take-off shaft 1D extends out of the transmission housing 4 and thus the power take-off space 4B. It extends parallel and laterally offset relative to the input shaft AN and the output shaft AB of the transmission. Thus, to the power take-off shaft 1D can be connected external auxiliary aggregates, which can be powered by it. So, drive power tapped off from the pump wheel 3A can be drawn by way of the power take-off shaft 1D of the power take-off 1. This is indicated by the arrow shown adjacent to the power take-off shaft 1D.

(12) The transmission transfers the drive power applied at the input shaft AN to the output shaft AB. This is indicated by the arrow shown adjacent to the output shaft AB. The output shaft AB, for example, is coupled via connecting shafts to drive wheels of the associated motor vehicle in order thereby to propel the motor vehicle.

(13) In the inside space 4C of the transmission are the transmission shifting elements 8 that can be actuated by a transmission control unit 7, as well as gearwheels and transmission shafts, for the purpose of engaging and disengaging the various gear ratio steps as necessary. Thus, the transmission elements required for the primary function of the transmission are accommodated in the inside space 4C of the transmission. These elements can be designed and arranged relative to one another in already familiar ways. Preferably, they are made and arranged relative to one another in accordance with FIG. 4 of DE 10 2005 002 337 A1. For more details, therefore, explicit reference should be made to the relevant explanations in DE 10 2005 002 337 A1.

(14) The transmission shown in FIG. 4 of DE 10 2005 002 337 A1 is inserted in the present FIG. 1 at bottom left. In that, the transmission shifting elements are denoted A, B, C, D and E. The arrow indicates that in the proposed motor vehicle transmission this is preferably but not imperatively used.

(15) In the present case the power take-off gearwheel 1A is rotatably supported radially and axially in the transmission housing 4. The power take-off gearwheel 1A is supported radially on the first intermediate wall 5 by means of a radial bearing arranged on it. The axial support preferably takes place on one side of the first intermediate wall 5 by means of a first axial bearing arranged on it, and on the other side, on the second intermediate wall 6 by means of a second axial bearing arranged on it. In FIG. 1 these bearings are not shown for the sake of simplicity.

(16) A preferred design of the mounting system is shown in FIG. 2. FIG. 2 shows part of a longitudinal section through a motor vehicle transmission according to FIG. 1, in the area of a power take-off 1 of the transmission.

(17) According to FIG. 2 the mounting of the power take-off gearwheel 1A comprises a radial roller bearing 9 and an axial roller bearing 10 and a thrust washer 11. The radial roller bearing 9 is in the form of a needle bearing or a cylindrical roller bearing. It is fitted on a tubular projection 5A of the first intermediate wall 5. The axial roller bearing 10 is arranged between a shoulder of the power take-off gearwheel 1A and an end face of a tubular projection 6A of the second intermediate wall 6. The thrust washer 11 is arranged axially between another shoulder of the power take-off gearwheel 1A and a shoulder of the projection 5A of the first intermediate wall 5.

(18) The gearteeth of the power take-off gearwheel 1A used for the power take-off 1 are in the form of helical teeth. Thus, during operation axial tooth forces act upon the power take-off gearwheel 1A. When the power take-off gearwheel 1A is rotating in its usual direction these forces act in the direction toward the second intermediate wall 6. Thus, the axial roller bearing 10 is positioned there in order to support these relatively large axial forces against the second intermediate wall 6. No axial forces, or hardly any, act toward the first intermediate wall 5. Thus it suffices to position the thrust washer 11 there. Since the loading of the thrust washer 11 is particularly low, it can even be made of plastic.

(19) The two intermediate walls 5, 6 are each made as separate intermediate plates. The intermediate plates are inserted axially into the transmission housing and fixed therein by screws. In the assembled condition the intermediate plates make the transmission more rigid and form part of the transmission housing 4.

(20) In the present case the hydraulic pump 2 is also connected to the power take-off gearwheel 1A in order to drive the hydraulic pump 2, as already explained earlier. For that purpose the power take-off gearwheel 1A has first teeth for the power take-off and second teeth for driving the hydraulic pump.

(21) According to FIG. 2 the teeth of the power take-off gearwheel 1A used for the power take-off mesh with the rotationally mounted intermediate wheel 1B of the power take-off 1. Axially adjacent to these first teeth the power take-off gearwheel 1A has second teeth. Compared with the first teeth, the second set of teeth has a smaller pitch circle diameter. The second teeth mesh with a link chain 2A for driving the hydraulic pump 2. Thus, the second teeth form chain sprockets. The pump 2 is let into the first intermediate wall 5, which supports it. Thus, the second teeth are closer to the intermediate wall 5 than are the first teeth. On the pump side the link chain 2A meshes with a chain wheel 2C on a rotatable pump shaft 2B of the pump 2. Thus, the pump 2 is necessarily coupled to the power take-off gearwheel 1A and is driven round when the power take-off gearwheel 1A rotates. The pump 2 can for example be in the form of an internal gearwheel pump.

(22) Thus, the intermediate wall 5 supports both the pump 2 and the power take-off gearwheel 1A. Consequently, no radial forces occur due to the driving of the pump outside the intermediate wall 5.

(23) In the area of the second intermediate wall 6, the power take-off gearwheel 1A is coupled to the pump wheel 3A by a coupling point 13. This coupling point 13 is for example in the form of an interlocking shaft-hub connection of the pump wheel 3A and the power take-off gearwheel 1A. In particular it is in the form of a spline or splined shaft. Thus, at that point 13, the pump wheel 3A engages in a corresponding entrainment feature of the power take-off gearwheel 1A. In this case the coupling point 13 is radially inside the tubular projection 6A of the second intermediate wall 6.

(24) The projection 6A of the second intermediate wall 6 also serves for the radial support of the pump wheel 3A. For this a further radial roller bearing 12 is provided, which is arranged radially between the pump wheel 3A and the projection 6A. The projection 6A can be made more rigid with the rest of the intermediate wall 6 by means of ribs. The same applies to the projection 5A and the intermediate wall 5.

(25) The power take-off gearwheel 1A has on one side a toothed section with the two sets of teeth for transmitting force to the power take-off 1 and to the pump 2, and on the other side a coupling section for coupling to the pump wheel 3A at the point 13. The coupling point 13 can be arranged radially inside the radial bearing 12. In that way the coupling point 13 can be accommodated in a space-saving manner. The axial roller bearing 10 is arranged on the shoulder of the power take-off gearwheel 1A formed by the taper between the coupling section and the toothed section thereof.

(26) According to FIG. 2, the power take-off gearwheel 1A is made integrally, in one piece. Thus, the power take-off gearwheel 1A is made from a single workpiece, from which the two sets of teeth are machined. The connection elements of the power take-off gearwheel 1A for the coupling point 13 can also be appropriately made from the same blank.

INDEXES

(27) 1 Power take-off 1A Power take-off gearwheel 1B Intermediate wheel 1D Power take-off shaft 2 Hydraulic pump 2A Link chain 2B Pump wheel 2C Chain wheel 3 Torque converter 3A Pump wheel 3B Turbine wheel 3C Stator wheel 3D Bridging clutch 4 Transmission housing 4A Inside space, torque converter space 4B Inside space, power take-off space 4C Inside space, transmission inside space 5 Intermediate wall 6 Intermediate wall 7 Transmission control unit 8 Transmission shifting element 9 Radial bearing 10 Axial bearing 11 Axial bearing, thrust washer 12 Radial bearing 13 Coupling point A, . . . , E Transmission shifting element AN Input shaft AB Output shaft