Vehicle transmission in group construction

Abstract

A motor vehicle transmission having main group and a range group that is connected downstream from the main group which has a planetary stage with transmission components. A first component couples an output shaft of the range group and a second component couples an output shaft of the main group. A third component can couple a housing and the first or the second components. For carrying out a range shift of the range group, which cannot be shifted under load, and to enable an arrangement of gear steps of the upstream main group, the drive output shaft passes axially through the planetary stage to the main group. The output shaft is a central shaft with which the input shaft of the main group can be connected in a rotationally fixed manner, and over which the output shaft of the main group is positioned as a coaxially extending hollow shaft.

Claims

1. A motor vehicle transmission, of a group configuration, comprising: an at least partially powershiftable main group (1), and a range group (2) connected downstream from the main group (1), the range group comprising a planetary stage (6) having transmission components comprising a ring gear (HO), a sun gear (SR), and a planetary carrier (ST) that guides at least one planetary gearwheel (PL1, PL2), wherein of these transmission components, a first transmission component is connected to a drive output shaft (AbW) of the range group (2) and a second transmission component is connected to an output shaft (AW) of the main group (1), and a third transmission component, on the one hand, is fixable to a housing (7) and, on the other hand, is couplable to either the first or the second transmission component, the drive output shaft (AbW) of the range group (2) is directly connectable in a rotationally fixed manner, to an input shaft of the main group (1) by a shifting element in such manner that a direct gear is formed when the drive output shaft (AbW) of the range group (2) is connected to the input shaft of the main group (1), and the drive output shaft (AbW) passes axially through the planetary stage (6) to the input shaft of the main group (1), and the drive output shaft (AbW) is a central shaft over which the output shaft (AW) of the main group (1) is positioned as a coaxially extending hollow shaft.

2. The motor vehicle transmission according to claim 1, wherein the drive output shaft (AbW) of the range group (2) is directly connectable, in a rotationally fixed manner, to the input shaft of the main group (1) by a single shifting element.

3. The motor vehicle transmission according to claim 1, wherein the drive output shaft (AbW) of the range group (2) is directly connectable, in a rotationally fixed manner, to the output shaft (AW) of the main group (1).

4. The motor vehicle transmission according to claim 1, wherein two countershaft gear arrangements (4, 5) are provided axially offset relative to the output shaft (AW) of the main group and to the at least one input shaft (EW1, EW2) of the main group, and gear steps (A to F) of the main group (1) located, on the one hand, between the at least one input shaft (EW1, EW2) of the main group and the countershaft gear arrangements (4, 5) and, on the other hand, between the output shaft (AW) of the main group and the countershaft gear arrangements (4, 5), in each case, comprise a gearwheel on a side of either the at least one input shaft (EW1, EW2) or the output shaft (AW) which, in each case, is in connection on both sides with gearwheels present in the countershaft gear arrangements (4, 5).

5. The motor vehicle transmission according to claim 1, wherein the main group (1) comprises of two partial transmissions which have input shafts (EW1, EW2) that extend coaxially with one another, and each of which is connectable into a force flow to the drive output shaft (AbW) of the range group in alternation by connecting its associated input shaft (EW1, EW2) to a drive input side (AN).

6. The motor vehicle transmission according to claim 1, wherein a gear step (F) of the main group (1), axially directly adjacent to the range group (2), is designed as a gearset of a reversing gear.

7. The motor vehicle transmission according to claim 1, wherein the planetary carrier (ST) is the first transmission component of the range group (2), the sun gear (SR) is the second transmission component of the range group (2), and the ring gear (HO) is the third transmission component of the range group (2).

8. The motor vehicle transmission according to claim 1, wherein a spur gear of a main gear produces at least one gear which forms an overdrive gear.

9. The motor vehicle transmission according to claim 1, wherein the direct gear is connectable to either the drive output shaft or to the sun gear of the range group by a double shifting element.

10. A motor vehicle transmission of group configuration, the transmission comprising: an at least partially powershiftable main group and a range group being connected downstream from the main group; the range group comprising a planetary stage having a ring gear, a sun gear, and a planetary carrier supporting at least one planetary gearwheel; a first one of the ring gear, the sun gear, and the planetary carrier being connected to a drive output shaft of the range group; a second one of the ring gear, the sun gear, and the planetary carrier being connected to an output shaft of the main group; a third one of the ring gear, the sun gear, and the planetary carrier being connectable to a housing in a rotationally fixed manner and being connectable to either the first or the second one of the ring gear, the sun gear, and the planetary carrier; the drive output shaft of the range group being directly connectable, via a shifting element, to an input shaft of the main group for forming a direct gear; and the drive output shaft of the range group being a central shaft passing axially through the planetary stage to the input shaft of the main group, and passing axially through the coaxially aligned output shaft of the main group which is a hollow shaft.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Below, further measures that improve the invention are indicated in more detail, along with the description of a preferred embodiment of the invention, which relates to the drawings represented in the figures, showing:

(2) FIG. 1: A schematic representation of a motor vehicle transmission according to a first preferred embodiment of the invention;

(3) FIG. 2: A shifting matrix for the transmission in FIG. 1;

(4) FIG. 3: A schematic representation of a motor vehicle transmission according to a second preferred embodiment of the invention;

(5) FIG. 4: A shifting matrix for the transmission in FIG. 3;

(6) FIG. 5: A schematic representation of a motor vehicle transmission according to a third preferred embodiment of the invention;

(7) FIG. 6: A shifting matrix for the transmission in FIG. 5.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

(8) FIG. 1 shows a schematic view of a motor vehicle transmission according to a first preferred embodiment of the invention, this motor vehicle transmission preferably being the transmission of a commercial vehicle. In this case the motor vehicle transmission comprises a main group 1 and a range group 2 connected downstream from the main group 1, the main group 1 and the range group 2 being provided between a drive input side AN and a drive output side AB of the motor vehicle transmission.

(9) As can be seen from FIG. 1, in the present case the main group 1 is designed in the form of a dual-clutch transmission and consists of two partial transmissions, each being associated with a respective input shaft EW1 and EW2. The input shaft EW1 of the first partial transmission is a central transmission shaft with which the input shaft EW2 of the second partial transmission, in the form of a hollow transmission shaft, is coaxial. The two partial transmissions can now each be linked in alternation into a force flow from the drive input side AN of the motor vehicle transmission, which in the assembled condition of the transmission is connected with a drive aggregate VM of the motor vehicle, to the drive output side AB, in that either the input shaft EW1 of the first partial transmission can be coupled to the drive input side AN by means of an associated powershift element K1 or the input shaft EW2 of the second partial transmission can be coupled thereto by means of a second powershift element K2. In this case the two powershift elements K1 and K2 are combined in a dual clutch 3, this being a wet-operating dual clutch.

(10) Furthermore, there extends coaxially with the two input shafts EW1 and EW2, an output shaft AW of the main group 1, which in this case is a hollow shaft. In addition, axially offset relative to the input shafts E1 and EW2 and also to the output shaft AW there are arranged two countershaft gear arrangements 4 and 5, each having a respective countershaft VW1 and VW2.

(11) Rotational movement of the drive input side AN can now on the one hand be transmitted via one of the two partial transmissions, with the corresponding transmission ratio, to the output shaft AW since the force flow, starting from the input shaft EW1 or EW2 concerned, passes via one of several gear steps A, B to the countershaft gear arrangement 4 and 5 and, starting from there, passes via one of several further gear steps C to F and on to the output shaft AW. However, apart from passing the force flow via the intermediate gears 4 and 5, the input shaft EW1 can also be coupled directly to the output shaft AW so that a direct through-drive to the output shaft and thus a direct gear of the main group 1 is defined.

(12) As can also be seen from FIG. 1, the gear steps A to F are arranged in a total of four wheel planes I to IV, such that each of the gear steps A to F has gearwheels Z1 and Z2 arranged rotationally fixed on the countershaft gear arrangements 4 and 5. In this case the gearwheel Z1 is located rotationally fixed on the countershaft VW1 of the first countershaft gear arrangement 4 and the gearwheel Z2 is rotationally fixed on the countershaft VW2 of the second countershaft gear arrangement 5. The gearwheels Z1 and Z2 are in each case in connection with a respective fixed wheel Z3 and Z4 arranged on the input shaft EW1 or the input shaft EW2, and form the input constants. The gearwheels Z5, Z6 and Z7 are loose wheels arranged on the countershafts VW1 and VW2, which mesh with fixed wheels Z9 and Z10 arranged on the output shaft AW of the main transmission.

(13) In gear step F the gearwheel Z8 arranged on the countershaft VW2 is connected to the intermediately positioned gearwheel Z10 in that between the gearwheels Z8 and Z10 there is arranged an intermediate wheel Z11, which meshes on one side with the radially inner gearwheel Z10 and on the other side with the respective radially outer gearwheel Z8. Consequently, during the transmission of rotational movements of the countershaft VW2 to the output shaft AW by way of the gear step F, compared with the other gear steps a reversed rotation direction of the output shaft is produced, i.e. a reversing gear of the main group 1 is defined.

(14) By means of the gear step A, rotational movement of the input shaft EW2 can now be transmitted to the countershaft gear arrangement 4 and by means of the gear step B, rotational movement of the input shaft EW1 can be transmitted to the countershaft gear arrangement 5. In the gear step C, the gearwheel Z5 of the gear step C can be connected rotationally fixed to the countershaft VW1 by means of a shifting element S1 and the gearwheel Z6 of the gear step E can be connected rotationally fixed to the countershaft VW1 by means of a shifting element S2. In the gear step D, the gearwheel Z7 of the gear step D can be connected rotationally fixed by means of a shifting element S3 to the countershaft VW2 and the gearwheel Z8 of the gear step F can be connected rotationally fixed by means of a shifting element S4 to the countershaft VW2.

(15) As a special feature, the gearwheel Z4 of the gear step B can also be coupled by means of a shifting element S5 to the drive output shaft AbW and also coupled by means of a shifting element S6 to the output shaft AW.

(16) In the present case the shifting elements S1 to S6 are each interlocking shifting elements in the form of claw clutches, and the shifting elements S1 and S2 are combined in a first shifting device SE1, the shifting elements S3 and S4 in a second shifting device SE2, and the shifting elements S5 and S6 in a third shifting device SE3. With each of the shifting devices SE1 to SE3 there is associated in each case one actuator (not shown here), by means of which a respective axially displaceable shifting claw of the shifting device SE1 or SE2 or SE3 concerned can be moved axially, thereby actuating the respectively associated shifting element S1 or S2 or S3 or S4, or S5 or S6.

(17) The range group 2 connected downstream from the main group 1 has a planetary stage 6 formed by the transmission components sun gear SR, planetary carrier ST and ring gear HO. In this case the planetary stage 6 is designed as a minus planetary gearset, in which the planetary carrier ST carries a number of planetary gearwheels PL1 and PL2 mounted to rotate upon it, these gearwheels meshing both with the radially inner sun gear SR and with the radially surrounding ring gear HO. In the present case the sun gear SR is arranged in a rotationally fixed manner on the output shaft AW of the main group 1, whereas the planetary carrier ST is coupled rotationally fixed to the drive output shaft AbW of the range group 2 which, at one end of the shaft, also forms the drive output side AB of the motor vehicle transmission.

(18) The ring gear HO of the planetary stage 6 can also on the one hand be connected rotationally fixed to the drive output shaft AbW by means of a shifting element S8, so that the ring gear HO rotates locked onto the planetary carrier ST, and on the other hand it can be fixed by a shifting element S7 to a surrounding housing 7. In the first case a locked rotation of the planetary carrier ST and the ring gear HO causes the sun gear connected to the output shaft AW also to rotate at the same rotational speed so that by way of the range group 2 a solid through-drive is obtained, this corresponding to a first, high gear of the range group 2. In contrast, if the ring gear is fixed to the surrounding housing 7 by the shifting element S7, then the planetary gearwheels PL1 and PL2 undergo rolling movements on the ring gear HO, which results in a slower rotational movement of the planetary carrier ST compared with the rotational speed of the sun gear SR. This corresponds to a second, lower gear of the range group 2. The shifting elements S7 and S8 are each designed as locking synchronizers and are combined in a fourth shifting device SE4, whose common sliding sleeve (not shown) can be displaced axially by an actuator (also not shown) either to a shift position that actuates the shifting element S7 or to one that actuates the shifting element S8.

(19) As a special feature the drive output shaft AbW of the range group 2 passes, on a side facing away from the drive output side AB, axially through the planetary stage 6 and extends to a point in front of the wheel plane III of the main group 1 ahead of it, so as to enable direct coupling to the input shaft EW1 when the shifting element S5 is actuated. in this case the drive output shaft AbW is made as a central shaft over which extends the output shaft AW in the form of a hollow shaft. In this case a rotationally fixed coupling between the input shaft EW1 and the drive output shaft AbW serves to bypass the range group 2 when shifting from the low gear of the range group 2 to its high gear. The force flow of the bypass gear (direct gear, 5.sup.th gear) passes directly from K1 via the shifting element S5 to the drive output shaft. The carrier ST of the range group 2 does not lie in this force flow path.

(20) Since owing to the design of the shifting elements S7 and S8 as locking synchronizers a change from the highest gear of the main group 1 when in the lower transmission ratio of the range group to the lowest gear of the main group 1 when in the higher range group transmission ratio, can only be carried out with interruption of the traction force, since the ring gear HO would first have to be decoupled from the drive output shaft AbW and then fixed to the housing 7. If now the input shaft EW1 is directly connected to the drive output shaft AbW by means of the shifting element S5, then direct transmission of rotational movement to the drive output shaft AbW takes place, whereby the planetary stage 6 of the range group 2 is shifted while free from load.

(21) By virtue of the design of the drive output shaft AbW it can be connected to the input shaft without problems during this and, nevertheless, the gear step F that defines a reversing gear of the main group 1 can be positioned axially adjacent to the range group 2, whereby the assembly effort for fitting the intermediate wheel Z11 is reduced. This is because in the transition area from the main group 1 to the range group 2 there is usually a parting plane of the housing 7, so that the intermediate wheel Z11 with its intermediate wheel bolt can be positioned without problems.

(22) FIG. 2 now shows an example shifting scheme for the motor vehicle transmission in FIG. 1. In total, eight powershiftable forward gears and two reversing gears can be obtained. The index UD denotes an underdrive situation, i.e. when the internal combustion engine is running at a higher speed than the drive output shaft AbW, whereas during an overdrive situation OD the internal combustion engine runs at a slower speed than the drive output shaft. As can be seen from FIG. 2, the first forward gear is obtained when the powershift element K1 is closed so that the input shaft EW1 is connected to the drive input side AN, and the shifting elements S6 and S7 are actuated. To change to the second forward gear the shifting element S2 has to be actuated in advance and then a shift between the powershift elements K1 and K2 is carried out and the shifting element S6 is opened. A third forward gear is obtained by actuating the shifting element S3 and then closing the powershift element K1, whereas a fourth forward gear is obtained by actuating the shifting element S1 and the powershift element K2.

(23) The fourth forward gear at the same time is the highest gear of the main group 1 when the range group 2 is set to its lower range, so that when shifting to the fifth forward gear in principle a shift in the range group 2 with load interruption would take place. This load interruption is now avoided in that only the shifting element S5, which connects the drive output shaft AbW to the input shaft EW1, is actuated. Owing to the actuation of the powershift element K1, the input shaft EW1 is then also coupled in a rotationally fixed manner to the drive input side AN.

(24) Following the fifth forward gear a sixth forward gear is obtained by actuating the shifting elements S2 and S8 as well as the powershift element K2. The next, seventh forward gear is obtained by actuating the shifting element S3 and closing the powershift element K1. Finally, the eighth forward gear is engaged by closing the shifting element S1 and changing the powershift element K2 to an actuated condition.

(25) For the two reversing gears in each case the powershift element K1 is closed, and in the first reversing gear the shifting elements S4 and S7 are closed, while for the second reversing gear the shifting elements S4 and S8 are closed.

(26) By virtue of the design of a motor vehicle transmission according to the invention, it is possible to realize a powershiftable bypassing of a range group 2 by directly connecting a drive output shaft AbW to an input shaft of the main group 1 upstream therefrom.

(27) FIG. 3 shows a schematic view of a second preferred embodiment of a motor vehicle transmission according to the invention, this motor vehicle transmission preferably also being that of a commercial vehicle. Thus, the motor vehicle transmission comprises a main group 1 and a range group 2 connected downstream from the main group 1, the main group 1 and range group 2 being provided between a drive input side AN and a drive output side AB of the motor vehicle transmission.

(28) The transmission in FIG. 3 is a dual-clutch transmission with two clutches K1 and K2, each of which connects an internal combustion engine (not shown) on the drive input side AN respectively to the input shafts EW1 and EW2 of two partial transmissions of the main transmission 1. The main transmission comprises two countershaft gear arrangements 4 and 5 with countershafts VW1 and VW2. The power is divided between the countershafts VW1 and VW2. Shifting devices SE1, SE2 and SE3 are fitted only on the main axis. The loose wheels Z2 and Z5 are arranged on the input shaft EW2 and the loose wheels Z8 and Z11 are arranged on the input shaft EW1, to which shafts they can be connected respectively by means of the shifting elements S5, S6, S3 and S4, these shifting elements S5, S6, S3 and S4 again being combined in shifting devices SE3 and SE2 respectively. In contrast, the fixed wheel Z14 is arranged on the output shaft AW of the main transmission 1.

(29) The fixed wheels Z1, Z3, Z4, Z6, Z7, Z9, Z10, Z12, Z13 and Z15 arranged on the countershafts mesh with the wheels Z2, Z5, Z8, Z11 and Z14. Thus, in the main transmission there are 5 gearset planes I, II, III, IV and V, in which 5 gear steps A to E are formed. In this case the gearset plane V forms a drive output constant. In the third gearset plane III there is an additional gearwheel Z16, which reverses the rotation direction for a reversing gear.

(30) In the force flow direction after the main transmission is arranged a range group 2 consisting of a planetary gearset with a sun gear SR, a planetary carrier ST on which planetary gearwheels PL1, PL2 etc, are mounted, and a ring gear HO. The carrier ST is connected in a rotationally fixed manner to the drive output shaft AbW and the sun gear to the output shaft AW of the main transmission. When the shifting element S8 is actuated the ring gear HO can be fixed onto the transmission housing. When the shifting element S7 is actuated the ring gear HO is connected to the sun gear SR in such manner that the range group 2 is in a block-rotation condition.

(31) The drive output shaft AbW can be connected directly to the input shaft EW1 by actuating the shifting element S1. This forms a direct gear by which the range group 2 is bypassed, so that it can be shifted while free from load,

(32) By actuating the shifting element S2 the input shaft EW1 can also be connected directly to the output shaft AW of the main transmission 1.

(33) FIG. 4 shows the shifting matrix for the transmission according to FIG. 3. The transmission has 8 forward gears and 2 reversing gears. Of the forward gears the 5.sup.th gear, which is the bypassing gear, is a direct gear while gears 1 to 4 are underdrive gears, i.e. in which the internal combustion engine (AN) rotates at a higher speed than the drive output shaft AbW. In contrast, gears 7 and 8 are overdrive gears, i.e. the internal combustion engine (AN) rotates more slowly than the drive output shaft AbW.

(34) FIG. 5 shows a schematic view of a further motor vehicle transmission according to a third embodiment of the invention, this motor vehicle transmission also preferably being that of a commercial vehicle. In this case too the motor vehicle transmission comprises a main group 1 and a range group 2 connected downstream from the main group 1, with the main group 1 and the range group 2 provided between a drive input side AN and a drive output side AB of the motor vehicle transmission.

(35) The transmission of FIG. 5 is again a dual-clutch transmission with two clutches K1 and K2, which connect an internal combustion engine (not shown) on the drive input side AN, respectively, to the input shafts EW1 and EW2 of two partial transmissions of the main transmission 1. The main transmission has two countershaft gear arrangements 4 and 5 with countershafts VW1 and VW2. In this case too a power division takes place between the countershafts VW1 and VW2. The shifting devices SE1, SE2 and SE3 and the single shifting element S3 are located only on the main axis. The loose wheels Z2 and Z5 are arranged on the input shaft EW2 and the loose wheel Z8 on the input shaft EW1, to which they can be connected, respectively, by means of the shifting elements S1, S2 and S3, of which the shifting elements S1 and S2 are combined in the shifting device SE1. The loose wheels Z11 and Z14, in contrast, are arranged on the output shaft AW of the main transmission 1 and can be connected thereto by the shifting elements S6 and S7, respectively, these again being combined in a shifting device SE3. By means of the shifting elements S4 and S5, which are combined in a shifting device SE2, the input shaft EW1 can be connected respectively to the drive output shaft AbW and to the output shaft AW of the main transmission.

(36) The fixed wheels Z1, Z3, Z4, Z6, Z7, Z9, Z10, Z12, Z13 and Z15 arranged on the countershafts VW1 and VW2 mesh with the wheels Z2, Z5, Z8, Z11 and Z14. Thus, in the main transmission there are 5 gearset planes I, II, III, IV and V, in which 5 gear steps A to E are formed. In the 5.sup.th gearset plane V there is an additional gearwheel Z16, which produces a rotation direction reversal for a reversing gear.

(37) The 1.sup.st gear is a so-termed coupling gear, in which the two partial transmissions are coupled. The 2.sup.nd gear is necessarily preselected thereby. The 6.sup.th gear is the same coupling gear, but in the fast range. Accordingly, the 7.sup.th gear is necessarily preselected. The 5-to-6 shift is carried out as a so-termed support gear shift. During this the 7.sup.th gear is preselected and the traction force is supported by means of that gear with the clutch K1 slipping, whereas with K2 the 5-to-6 shift is carried out without any friction work.

(38) In the force flow direction after the main transmission is arranged a range group 2 consisting of a planetary gearset with a sun gear SR, a planetary carrier ST on which planetary gearwheels PL1, PL2 etc. are mounted, and a ring gear HO. The carrier ST is connected in a rotationally fixed manner to the drive output shaft AbW and the sun gear to the output shaft AW of the main transmission. When the shifting element S9 is actuated the ring gear HO can be fixed onto the transmission housing. When the shifting element S8 is actuated the ring gear HO is connected to the sun gear SR in such manner that the range group 2 is in a block-rotation condition.

(39) The drive output shaft AbW can be connected directly to the input shaft EW1 by actuating the shifting element S4. This forms a direct gear which bypasses the range group 2, so that it can be shifted while free from load.

(40) By actuating the shifting element S5, the input shaft EW1 can also be connected directly to the output shaft AW of the main transmission 1.

(41) FIG. 6 shows the shifting matrix for the transmission of FIG. 5. The transmission has 10 forward gears and 3 reversing gears. Of the forward gears, the 7.sup.th gear, which forms the bypassing gear, is a direct gear whereas the gears 1 to 6 are underdrive gears, i.e. in which the internal combustion engine (AN) rotates faster than the drive output shaft AbW. Gears 8 to 10, in contrast, are overdrive gears, i.e. the internal combustion engine (AN) rotates more slowly than the drive output shaft AbW.

INDEXES

(42) TABLE-US-00001 1 Main group 2 Range group 3 Dual clutch 4 First countershaft gear arrangement 5 Second countershaft gear arrangement 6 Planetary stage 7 Housing I First wheel plane II Second wheel plane III Third wheel plane IV Fourth wheel plane V Fifth wheel plane AN Drive input side AB Drive output side EW1 Input shaft EW2 Input shaft VW1 Countershaft VW2 Countershaft AW Output shaft of the main transmission AbW Drive output shaft Z1 Gearwheel Z2 Gearwheel Z3 Gearwheel Z4 Gearwheel Z5 Gearwheel Z6 Gearwheel Z7 Gearwheel Z8 Gearwheel Z9 Gearwheel Z10 Gearwheel Z11 Gearwheel Z12 Gearwheel Z13 Gearwheel Z14 Gearwheel Z15 Gearwheel Z16 Gearwheel S1 Shifting element S2 Shifting element S3 Shifting element S4 Shifting element S5 Shifting element S6 Shifting element S7 Shifting element S8 Shifting element S9 Shifting element SE1 Shifting device SE2 Shifting device SE3 Shifting device SE4 Shifting device A to F Gear steps HO Ring gear ST Planetary carrier SR Sun gear PL1 Planetary gearwheel PL2 Planetary gearwheel K1 Powershift element K2 Powershift element