JP7472725B2 - Vehicle power transmission system - Google Patents

Description

The present invention relates to a vehicle power transmission device.

In vehicles such as automobiles, a transmission and a differential device are provided on the power transmission path from a drive source such as an engine to the drive wheels, and power from the drive source is transmitted through the transmission and differential device to a drive shaft extending in the vehicle width direction, and then from the drive shaft to the drive wheels.

In vehicles with a longitudinally mounted transmission for front-engine, rear-wheel drive vehicles, the engine and transmission are located at the front of the vehicle, and power from the engine is transmitted from the transmission through a propeller shaft to a rear-wheel differential device located at the rear of the vehicle, and then to the rear wheels via a drive shaft.

In addition, in vehicles with a longitudinally mounted transmission for front-engine, rear-wheel drive-based four-wheel drive vehicles, a transfer device is provided that distributes the power from the engine output from the transmission to the front wheels, and the power from the engine is transmitted from the transfer device through a front-wheel propeller shaft to a front-wheel differential device located at the front of the vehicle body, and then to the front wheels via a drive shaft.

For example, Patent Document 1 discloses that in a vehicle equipped with a longitudinally mounted transmission for a front-engine, rear-drive based four-wheel drive vehicle, a drive shaft is disposed forward of a transmission such as a continuously variable transmission disposed at the front of the vehicle body and rearward of a starting clutch, extending in the vehicle width direction.

JP 2003-509263 A

In vehicles such as sports-type front-engine, rear-drive cars, the drive source such as the engine is located at the front of the vehicle, and a vertically mounted transmission is sometimes located near the drive shaft at the rear of the vehicle in order to increase the weight of the rear of the vehicle. In such cases, power is transmitted from the drive source to the transmission via a propeller shaft, and from the transmission to the drive wheels located at the rear of the vehicle via a differential device and drive shaft located at the rear of the vehicle.

In such vehicles, if the transmission located at the rear of the vehicle body is located in front of the drive shaft, the cabin space will be narrow, so it is possible to place the transmission above the drive shaft, but this could raise the center of gravity of the vehicle and cause a decrease in handling stability. On the other hand, if the transmission is located below the drive shaft, the gap with the ground will be small, making it difficult to ensure ground clearance in sports vehicles, etc.

The present invention aims to provide a power transmission device for a vehicle that can improve driving stability while ensuring sufficient ground clearance when the vehicle is equipped with a longitudinally mounted transmission and the transmission is located near the drive shaft at the rear of the vehicle body.

The present invention relates to a power transmission device for a vehicle, the power transmission device including a transmission that changes the speed of power input from a drive source and outputs the power, and a drive shaft that is connected to the transmission and transmits the power from the drive source output from the transmission to drive wheels, the transmission having a speed change mechanism that is disposed in a transmission case with an axis extending in the front-rear direction of the vehicle body and changes the speed of the power from the drive source, the drive shaft extends in the vehicle width direction at the center side of the transmission mechanism in the vertical direction of the vehicle body, and is provided penetrating the transmission case. the transmission mechanism comprises an input shaft and an output shaft arranged on the same axis, a counter shaft arranged parallel to the input shaft and the output shaft, a transmission gear section having a plurality of gear trains each including a first gear provided on the input shaft or the output shaft and a second gear provided on the counter shaft and meshing with the first gear, and a transmission gear operating section for operating the transmission gear section, and the drive shaft extends in the vehicle width direction between the transmission gear section and the transmission gear operating section .

According to the present invention, when a vehicle equipped with a longitudinally mounted transmission has the transmission disposed near the drive shaft at the rear of the vehicle body, the drive shaft extends in the vehicle width direction through the transmission case at the vertical center of the transmission mechanism, lowering the center of gravity of the vehicle and improving handling stability compared to when the transmission is disposed above the drive shaft. Also, compared to when the transmission is disposed below the drive shaft, the clearance from the ground is increased, ensuring ground clearance.

Therefore, in a vehicle equipped with a longitudinally mounted transmission, in the case where the transmission is disposed in the rear portion of the vehicle body near the drive shaft, it is possible to improve the driving stability while ensuring sufficient ground clearance.
Since the drive shaft extends in the vehicle width direction between the transmission gear section and the transmission gear operating section, the drive shaft can be positioned between the transmission gear sections and the transmission gear operating sections that are distributed in the vertical direction of the vehicle body with good assembly ease, compared to a case in which the drive shaft extends in the vehicle width direction between the transmission gear sections and the transmission gear operating sections, and the drive shaft and transmission can be positioned with good assembly ease.

The drive shaft preferably extends in the vehicle width direction at a position in the vehicle front-rear direction corresponding to a predetermined gear train among the plurality of gear trains in which the vertical dimensions of the first gear and the second gear are small.

With this configuration, the drive shaft extends in the vehicle width direction at a position in the vehicle front-rear direction that corresponds to a specific gear train among the multiple gear trains in which the vertical dimensions of the first and second gears are small, so the drive shaft can be positioned close to the axis of the transmission mechanism, allowing the transmission and drive shaft to be positioned compactly in the vertical direction of the vehicle.

The power transmission device of the vehicle includes a differential device that is connected to the transmission and to the drive shaft to transmit the power from the drive source output from the transmission to the drive shaft.

With this configuration, in a vehicle equipped with a differential device connected to a longitudinally mounted transmission and also connected to a drive shaft, the drive shaft extends in the vehicle width direction through the transmission case at the center of the vertical direction of the transmission mechanism, thereby improving handling stability while ensuring ground clearance.

It is preferable that the differential housing is provided to house the differential device, and that the differential housing is formed integrally with the transmission case.

With this configuration, the differential housing is formed integrally with the transmission case, so the differential housing and transmission case can be made more compact than when the differential housing is not formed integrally with the transmission case and is arranged in the vehicle width direction.

According to the present invention, when a vehicle equipped with a longitudinally mounted transmission has the transmission positioned near the drive shaft at the rear of the vehicle body, it is possible to improve the driving stability while maintaining ground clearance.

1 is a schematic diagram of a vehicle equipped with a power transmission device according to an embodiment of the present invention. FIG. 2 is a perspective view of the power transmission device. FIG. 2 is a schematic diagram of the power transmission device. FIG. 2 is a perspective view of a transmission and a differential device. FIG. 2 is a top view of the transmission, the differential and the drive shaft. FIG. 2 is a top view of a transmission gear portion of the transmission. 6 is a side view of a speed change mechanism of the transmission as seen from a Y7 direction in FIG. 5 . 6 is a cross-sectional view of the main parts of the transmission, the differential device, and the drive shaft taken along the line Y8-Y8 in FIG. 5.

The following describes an embodiment of the present invention with reference to the attached drawings.

Figure 1 is a schematic diagram of a vehicle equipped with a power transmission device according to an embodiment of the present invention. As shown in Figure 1, the vehicle 1 is a front-engine, rear-drive vehicle such as a sports type with a low driver's seat and a low center of gravity, and has an engine 2 disposed at the front of the vehicle body as a drive source, and a longitudinally mounted transmission 3 disposed at the rear of the vehicle body near a drive shaft 4 extending in the vehicle width direction.

The power transmission device 5 according to this embodiment is provided with a transmission 3 at the rear of the vehicle body on a power transmission path from the engine 2 to the rear wheels 6 as drive wheels, which is adapted to change the speed of the power input from the engine 2 and output the power, and a drive shaft 4 connected to the transmission 3 to transmit the power from the engine 2 output from the transmission 3 to the rear wheels 6, as well as a differential device 7 connected to the transmission 3 and to the drive shaft 4 to transmit the power from the engine 2 output from the transmission 3 to the drive shaft 4.

Power from the engine 2 is transmitted to the transmission 3 via a propeller shaft 8 that extends in the fore-and-aft direction of the vehicle body, and from the transmission 3 it is transmitted to the left and right rear wheels 6 via a differential device 7 and a drive shaft 4.

In the vehicle 1, a tunnel section 10a is formed at the center of the width of the vehicle of the floor panel 10 that constitutes the bottom surface of the passenger compartment 9, bulging upward from the vehicle body and extending in the longitudinal direction of the vehicle body, and the propeller shaft 8 is disposed in the space inside the tunnel section 10a. The front side of the vehicle body of the transmission 3 that is connected to the propeller shaft 8 is also disposed within the tunnel section 10a.

Figure 2 is a perspective view of the power transmission device. As shown in Figure 2, the transmission 3 is disposed near the drive shaft 4. As described below, the transmission 3 has a transmission mechanism 20 that is disposed in a transmission case 11 with its axis extending in the fore-aft direction of the vehicle body and that changes the speed of the power from the engine 2. The transmission case 11 is formed in a roughly cylindrical shape and extends in the fore-aft direction of the vehicle body, with the front side of the vehicle body covered by a front housing 12 and the rear side of the vehicle body covered by a rear housing 13.

The differential device 7 is disposed on one side of the transmission 3 in the vehicle width direction, i.e., on the left side of the vehicle body. The differential device 7 is connected to a drive shaft 4 that extends on both sides in the vehicle width direction. The differential housing 14 that houses the differential device 7 is disposed on the left side of the transmission case 11 in the vehicle body and is formed integrally with the transmission case 11.

The differential housing 14 includes a first housing 15 that constitutes the right side of the vehicle body, which is the other side in the vehicle width direction of the differential housing 14, and houses the right side of the differential device 7, and a second housing 16 that constitutes the left side of the vehicle body of the differential housing 14 and houses the left side of the differential device 7.

The differential housing 14 is formed integrally with the transmission case 11 by molding the first housing 15 integrally with the transmission case 11 and fastening the second housing 16 to the first housing 15 using fastening bolts. The second housing 16 is provided with a shaft insertion portion 16a through which the drive shaft 4a extending from the differential device 7 to the left side of the vehicle body is inserted.

The transmission case 11 has a bottom surface portion 11a, side surface portions 11b on both sides in the vehicle width direction, and a top surface portion 11c. As shown in FIG. 8, the side surface portion 11b on the left side of the vehicle body is integrally molded with the first housing 15 and is provided with a shaft insertion portion 11d through which the drive shaft 4b extending from the differential device 7 to the right side of the vehicle body is inserted. The side surface portion 11b on the right side of the vehicle body is also provided with a shaft insertion portion 11e through which the drive shaft 4b is inserted. The drive shaft 4b extends in the vehicle width direction through the transmission case 11 via the shaft insertion portions 11d and 11e.

Figure 3 is a schematic diagram of the power transmission device. As shown in Figure 3, the transmission 3 is configured to achieve six forward speeds and one reverse speed. The transmission 3 has a speed change mechanism 20 that changes the speed of the power from the engine 2.

The transmission mechanism 20 is provided in the transmission case 11 with an input shaft 30 to which the output from the engine 2 is input via a clutch (not shown), an output shaft 40 that is arranged coaxially with the input shaft 30 and outputs power from the engine 2, and a counter shaft 50 that is arranged parallel to the input shaft 30 and the output shaft 40. The input shaft 30, the output shaft 40, and the counter shaft 50 are each arranged so that their axes extend in the fore-and-aft direction of the vehicle body.

The input shaft 30 is rotatably supported by the transmission case 11 via a bearing 17. The output shaft 40 is rotatably supported by the transmission case 11 via a bearing 18. The rear end of the input shaft 30 is rotatably fitted to the front end of the output shaft 40. The counter shaft 50 is rotatably supported by the transmission case 11 via a bearing 19.

A fourth-speed drive gear 31 is fixed to the input shaft 30 on the front side of the vehicle body. A sixth-speed driven gear 32, a fifth-speed driven gear 33, a second-speed driven gear 34, a third-speed driven gear 35, a first-speed driven gear 36, and a reverse-speed driven gear 37 are loosely fitted to the output shaft 40, in that order from the front side of the vehicle body.

On the counter shaft 50, in order from the front of the vehicle body, a 4th gear driven gear 41, a 6th gear drive gear 42, a 5th gear drive gear 43, a 2nd gear drive gear 44, a 3rd gear drive gear 45, a 1st gear drive gear 46, and a reverse gear drive gear 47 are fixed.

The fourth-speed gear train G4 is made up of the fourth-speed drive gear 31 and the fourth-speed driven gear 41 that is constantly meshed with the fourth-speed drive gear 31. When the shift lever is operated to fourth gear, the input shaft 30 and the output shaft 40 are directly connected to achieve fourth gear. The fourth-speed gear train G4 functions as a reduction gear train that reduces the rotation of the input shaft 30 at a fixed reduction ratio and transmits it to the counter shaft 50.

The 1st gear driven gear 36, the 2nd gear driven gear 34, the 3rd gear driven gear 35, the 5th gear driven gear 33, and the 6th gear driven gear 32, and the 1st gear drive gear 46, the 2nd gear drive gear 44, the 3rd gear drive gear 45, the 5th gear drive gear 43, and the 6th gear drive gear 42 that are constantly meshed with the 1st gear driven gear 36, the 2nd gear driven gear 34, the 3rd gear driven gear 35, the 5th gear driven gear 33, and the 6th gear driven gear 32, respectively, form a 1st gear gear train G1, a 2nd gear gear train G2, a 3rd gear gear train G3, a 5th gear gear train G5, and a 6th gear gear train G6, respectively.

The 4th-speed drive gear 31 provided on the input shaft 30, the 1st-speed driven gear 36, the 2nd-speed driven gear 34, the 3rd-speed driven gear 35, the 5th-speed driven gear 33, and the 6th-speed driven gear 32 provided on the output shaft 40 are formed so that the gear diameter, which is the outer diameter of the gear, becomes smaller as the gear speed increases.

The 1st gear drive gear 46, 2nd gear drive gear 44, 3rd gear drive gear 45, 4th gear driven gear 41, 5th gear drive gear 43, and 6th gear drive gear 42 provided on the counter shaft 50 are formed with larger gear diameters as the gear shift stage increases.

In the transmission 3, among the 1st gear train G1 to the 6th gear train G6, the 3rd gear train G3 and the 4th gear train G4, which are the medium gear trains, are formed with a smaller maximum gear diameter of the two gears that make up each gear train, compared to the 1st gear train G1 and the 2nd gear train G2, which are the low gear trains, and the 5th gear train G5 and the 6th gear train G6, which are the high gear trains. The 3rd gear train G3 is formed with the smallest maximum gear diameter of the two gears that make up each gear train, among the 1st gear train G1 to the 6th gear train G6.

The reverse gear driven gear 37 and the reverse gear drive gear 47 do not mesh with each other, but always mesh with a reverse gear idle gear that is loosely fitted to a reverse shaft arranged in parallel to the input shaft 30, the output shaft 40, and the counter shaft 50 inside the transmission case 11. The reverse gear driven gear 37, the reverse gear drive gear 47, and the reverse gear idle gear form a reverse gear gear train GR.

The transmission mechanism 20 includes a transmission gear section 21 having a plurality of gear trains each consisting of a first gear provided on the input shaft 30 or the output shaft 40 and a second gear provided on the counter shaft 50 and meshing with the first gear. The first gear driven gear 36, the second gear driven gear 34, the third gear driven gear 35, the fourth gear drive gear 31, the fifth gear driven gear 33, and the sixth gear driven gear 32 constitute the first gears 31-36, the first gear drive gear 46, the second gear drive gear 44, the third gear drive gear 45, the fourth gear driven gear 41, the fifth gear drive gear 43, and the sixth gear drive gear 42 constitute the second gears 41-46, and the first gear gear train G1 to the sixth gear gear train G6 constitute a plurality of gear trains G1-G6, each of which is made up of a first gear and a second gear.

Furthermore, a first mesh clutch 51 is provided on the vehicle body front side of the sixth-speed driven gear 32, a second mesh clutch 52 is provided between the fifth-speed driven gear 33 and the second-speed driven gear 34, a third mesh clutch 53 is provided between the third-speed driven gear 35 and the first-speed driven gear 36, and a fourth mesh clutch 54 is provided on the vehicle body front side of the reverse-speed driven gear 37. The mesh clutches 51, 52, 53, and 54 are formed in substantially the same manner.

The first mesh clutch 51 has a disk-shaped clutch ring 51a that is connected to the output shaft 40 so as not to rotate relative to it and is movable relative to the axial direction of the output shaft 40. The clutch ring 51a has a plurality of clutch teeth 51b that protrude in the axial direction of the output shaft 40 on the surface on the front side of the vehicle body. The plurality of clutch teeth 51b extend radially in the radial direction of the output shaft 40 and are arranged at equal intervals in the circumferential direction of the output shaft 40.

The fourth-speed drive gear 31 is provided with a number of clutch teeth 31a that protrude in the axial direction of the output shaft 40 in correspondence with the clutch teeth 51b of the clutch ring 51a. The clutch teeth 31a extend radially in the radial direction of the output shaft 40 and are arranged at equal intervals in the circumferential direction of the output shaft 40.

The clutch teeth 51b and the clutch teeth 31a are formed to engage when the clutch ring 51a is moved toward the fourth-speed drive gear 31. When the clutch teeth 51b and the clutch teeth 31a are engaged and the clutch ring 51a is engaged with the fourth-speed drive gear 31, the input shaft 30 and the output shaft 40 are directly connected, and the rotation of the input shaft 30 is transmitted to the output shaft 40.

The clutch ring 51a has multiple clutch teeth 51c on the rear surface of the vehicle body that protrude in the axial direction of the output shaft 40. The multiple clutch teeth 51c extend radially in the radial direction of the output shaft 40 and are arranged at equal intervals around the circumference of the output shaft 40.

The sixth-speed driven gear 32 is provided with a number of clutch teeth 32a that protrude in the axial direction of the output shaft 40 in correspondence with the clutch teeth 51c of the clutch ring 51a, and the clutch teeth 32a extend radially in the radial direction of the output shaft 40 and are arranged at equal intervals around the circumference of the output shaft 40.

The clutch teeth 51c and the clutch teeth 32a are formed to engage when the clutch ring 51a is moved toward the sixth-speed driven gear 32. When the clutch teeth 51c and the clutch teeth 32a are engaged and the clutch ring 51a is engaged with the sixth-speed driven gear 32, the sixth-speed gear train G6 is in a power transmission state. The sixth-speed driven gear 32 is connected to the output shaft 40, and the rotation of the input shaft 30 is transmitted to the counter shaft 50 by the reduction gear train G4 and to the output shaft 40 by the sixth-speed gear train G6.

The second mesh clutch 52 has a clutch ring 52a with multiple clutch teeth 52b on the front side of the vehicle body and multiple clutch teeth 52c on the rear side of the vehicle body.

The fifth-speed driven gear 33 is provided with a plurality of clutch teeth 33a corresponding to the plurality of clutch teeth 52b of the clutch ring 52a, and the second-speed driven gear 34 is provided with a plurality of clutch teeth 34a corresponding to the plurality of clutch teeth 52c of the clutch ring 52a.

The clutch teeth 52b and the clutch teeth 33a are formed to engage when the clutch ring 52a is moved toward the 5th-speed driven gear 33. The clutch teeth 52c and the clutch teeth 34a are formed to engage when the clutch ring 52a is moved toward the 2nd-speed driven gear 34.

When the clutch ring 52a is engaged with the fifth-speed driven gear 33, the fifth-speed gear train G5 is in a power transmission state, and the rotation of the input shaft 30 is transmitted to the output shaft 40 via the reduction gear G4 and the sixth-speed gear train G6. When the clutch ring 52a is engaged with the second-speed driven gear 34, the second-speed gear train G2 is in a power transmission state, and the rotation of the input shaft 30 is transmitted to the output shaft 40 via the reduction gear G4 and the second-speed gear train G2.

The third mesh clutch 53 has a clutch ring 53a with multiple clutch teeth 53b on the front side of the vehicle body and multiple clutch teeth 53c on the rear side of the vehicle body.

The third-speed driven gear 35 is provided with multiple clutch teeth 35a corresponding to the multiple clutch teeth 53b of the clutch ring 53a, and the first-speed driven gear 36 is provided with multiple clutch teeth 36a corresponding to the multiple clutch teeth 53c of the clutch ring 53a.

The clutch teeth 53b and the clutch teeth 35a are formed to engage when the clutch ring 53a is moved toward the third-speed driven gear 35. The clutch teeth 53c and the clutch teeth 36a are formed to engage when the clutch ring 53a is moved toward the first-speed driven gear 36.

When the clutch ring 53a is engaged with the third-speed driven gear 35, the third-speed gear train G3 is in a power transmission state, and the rotation of the input shaft 30 is transmitted to the output shaft 40 via the reduction gear G4 and the third-speed gear train G3. When the clutch ring 53a is engaged with the first-speed driven gear 36, the first-speed gear train G1 is in a power transmission state, and the rotation of the input shaft 30 is transmitted to the output shaft 40 via the reduction gear G4 and the first-speed gear train G1.

The fourth mesh clutch 54 has a clutch ring 54a with multiple clutch teeth 54b on the front surface of the vehicle body. The reverse gear driven gear 37 has multiple clutch teeth 37a corresponding to the multiple clutch teeth 54b of the clutch ring 54a. The clutch teeth 54b and the clutch teeth 37a are formed so as to engage when the clutch ring 54a is moved toward the reverse gear driven gear 37.

When the clutch ring 54a is engaged with the reverse gear driven gear 37, the reverse gear gear train GR is placed in a power transmission state, and the rotation of the input shaft 30 is transmitted to the output shaft 40 via the reduction gear G4 and the reverse gear gear train GR.

The transmission mechanism 20 also includes a transmission gear operating unit 22 that operates the transmission gear unit 21. The transmission gear operating unit 22 includes a number of shift rods 61, 62, 63, 64 that extend linearly in the fore-and-aft direction of the vehicle body, and the multiple shift rods 61, 62, 63, 64 are arranged parallel to one another and support multiple shift forks 61a, 62a, 63a, 64a, respectively.

The transmission 3 includes, from the left side of the vehicle body, a first shift rod 61, a second shift rod 62, a third shift rod 63, and a fourth shift rod 64. The first shift rod 61, the second shift rod 62, the third shift rod 63, and the fourth shift rod 64 support a first shift fork 61a, a second shift fork 62a, a third shift fork 63a, and a fourth shift fork 64a, which engage with clutch rings 51a, 53a, 54a, and 52a, respectively.

The outer periphery of each clutch ring 51a, 53a, 54a, 52a is received in a recess provided at the tip of each shift fork 61a, 63a, 64a, 62a, and the movement of each shift fork 61a, 63a, 64a, 62a moves each clutch ring 51a, 53a, 54a, 52a in the axial direction of the output shaft 40.

The speed change gear operating unit 22 also includes a shift drum 65 having shift grooves 65a, 65b, 65c, and 65d corresponding to the shift rods 61, 62, 63, and 64, and a motor 66 as an actuator that rotates and drives the shift drum 65 to move the multiple shift rods 61, 62, 63, and 64.

The shift drum 65 is formed in a cylindrical shape, and a first shift groove 65a, a second shift groove 65b, a third shift groove 65c, and a fourth shift groove 65d are formed on the outer circumferential surface of the shift drum 65, corresponding to the first shift rod 61, the second shift rod 62, the third shift rod 63, and the fourth shift rod 64, respectively.

The first shift groove 65a, the second shift groove 65b, the third shift groove 65c and the fourth shift groove 65d engage with protrusions 61c, 62c, 63c and 64c provided at the tips of the first shift arm 61b, the second shift arm 62b, the third shift arm 63b and the fourth shift arm 64b, which are fixed and supported by the first shift rod 61, the second shift rod 62, the third shift rod 63 and the fourth shift rod 64, respectively.

The motor 66 rotates the shift drum 65 based on the operation of the shift lever to move the multiple shift rods 61, 62, 63, and 64. When the shift drum 65 is rotated by the motor 66, the shift rods 61, 62, 63, and 64 are selectively moved in the axial direction via the shift arms 61b, 62b, 63b, and 64b according to the shift grooves 65a, 65b, 65c, and 65d.

Then, the shift forks 61a, 62a, 63a, and 64a supported by the shift rods 61, 62, 63, and 64 are moved, and the mesh clutches 51, 53, 54, and 52 are selectively operated. As a result, by operating the shift lever, upshifts, downshifts, and reverse changes are performed, and six forward speeds and one reverse speed are achieved.

In the transmission 3, an output gear 38 is fixed to the output shaft 40 on the rear side of the reverse gear driven gear 37, and the output gear 38 meshes with an input gear 24 fixed to the rear side of a drive pinion 23 extending in the fore-and-aft direction of the vehicle. The drive pinion 23 is rotatably supported on the transmission case 11. The power from the engine 2 output from the transmission 3 is transmitted to the differential device 7 via the drive pinion 23.

The differential device 7 has a differential case 26 rotatably supported in the differential housing 14, and a ring gear 27 fixed to the differential case 26. The ring gear 27 meshes with the drive pinion 23 and is disposed on the left side of the drive pinion 23 in the vehicle body.

The differential device 7 also has a differential mechanism 28. The differential mechanism 28 has a pinion shaft 29a fixed to the differential case 26 and extending in a direction perpendicular to the vehicle width direction, a pair of opposing pinion gears 29b rotatably fitted to the pinion shaft 29a, and a pair of left and right side gears 29c that mesh with the pair of pinion gears 29b.

A drive shaft 4 extending in the vehicle width direction is spline-fitted to each of the pair of side gears 29c. The drive shaft 4 is capable of rotating together with the side gears 29c relative to the differential housing 14 and the differential case 26. The left rear wheel 6 is connected to the drive shaft 4a, and the right rear wheel 6 is connected to the drive shaft 4b.

The differential device 7 is connected to the transmission 3 and also to the drive shaft 4, and transmits the power from the engine 2 output from the transmission 3 to the drive shaft 4, and the drive shaft 4 is connected to the transmission 3 via the drive pinion 23 and the differential device 7, and transmits the power from the engine 2 output from the transmission 3 to the rear wheels 6.

In this embodiment, the drive shaft 4 extends in the vehicle width direction at the center of the speed change mechanism 20 of the transmission 3 in the vehicle front-rear direction. The drive shaft 4 is arranged in a position that overlaps in the vehicle front-rear direction with the portion of the speed change gear unit 21 where the multiple gear trains G1 to G6 are arranged. The drive shaft 4 also extends in the vehicle width direction at a position that overlaps in the vehicle vertical direction at the center of the speed change mechanism 20 of the transmission 3 in the vehicle vertical direction.

Next, the power transmission device according to an embodiment of the present invention will be further described with reference to Figures 4 to 8.

Figure 4 is a perspective view of the transmission and differential device, Figure 5 is a top view of the transmission, differential device and drive shaft, Figure 6 is a top view of the transmission's shift gear section, Figure 7 is a side view of the transmission's shift gear operating section as viewed from the Y7 direction in Figure 5, and Figure 8 is a side view of the transmission's shift mechanism section as viewed from the Y7 direction in Figure 5. Figures 4 to 8 show the transmission case and differential housing removed, and Figure 7 also shows the drive shaft.

As shown in Figures 4 to 8, the transmission 3 is disposed near the drive shaft 4 and has a transmission mechanism 20 arranged in the transmission case 11 with its axis extending in the fore-and-aft direction of the vehicle body. The transmission mechanism 20 includes an input shaft 30, an output shaft 40, a counter shaft 50, a transmission gear section 21 having a plurality of gear trains G1 to G6 each consisting of first gears 31 to 36 provided on the input shaft 30 or the output shaft 40 and second gears 41 to 46 provided on the counter shaft 50, and a transmission gear operating section 22 that operates the transmission gear section 21.

The differential device 7 is disposed on the left side of the transmission 3, and receives the power output from the engine 2 via a drive pinion 23 extending in the longitudinal direction of the vehicle body, and transmits the power from the engine 2 to a drive shaft 4 extending in the width direction of the vehicle. The left and right drive shafts 4 transmit the power from the engine 2 to the left and right rear wheels 6, respectively.

As shown in FIG. 6, in the transmission gear section 21, the input shaft 30 and the output shaft 40 extend linearly in the fore-and-aft direction of the vehicle body. The counter shaft 50 extends linearly in the fore-and-aft direction of the vehicle body in parallel with the input shaft 30 and the output shaft 40. The input shaft 30, the output shaft 40, and the counter shaft 50 extend horizontally or substantially horizontally.

As shown in FIG. 8, the input shaft 30, the output shaft 40, and the counter shaft 50 are spaced apart in the vehicle width direction and are arranged in positions that overlap in the vertical direction of the vehicle body. The reverse shaft 25 extends linearly in the fore-aft direction of the vehicle body parallel to the input shaft 30, the output shaft 40, and the counter shaft 50, and extends horizontally or substantially horizontally below the input shaft 30, the output shaft 40, and the counter shaft 50.

As shown in FIG. 6, the speed change gear section 21 has, from the front of the vehicle, first gears 31-36 provided on the input shaft 30 or the output shaft 40, which are a fourth-speed drive gear 31, a sixth-speed driven gear 32, a fifth-speed driven gear 33, a second-speed driven gear 34, a third-speed driven gear 35, and a first-speed driven gear 36, and second gears 41-46 provided on the counter shaft 50, which are, from the front of the vehicle, a fourth-speed driven gear 41, a sixth-speed drive gear 42, a fifth-speed drive gear 43, a second-speed drive gear 44, a third-speed drive gear 45, and a first-speed drive gear 46.

The gear trains G1 to G6 are each made up of first gears 31 to 36 and second gears 41 to 46, and are arranged in the following order from the front of the vehicle body: 4th gear train G4, 6th gear train G6, 5th gear train G5, 2nd gear train G2, 3rd gear train G3, and 1st gear train G1.

Of the first gear train G1 to the sixth gear train G6, the third gear train G3 has the smallest maximum gear diameter (gear diameter) of the first and second gears that make up each gear train, and the first and second gears have the smallest vertical dimensions.

As shown in FIG. 7, the drive shaft 4 is disposed above the transmission gear unit 21 and extends in the vehicle width direction at the center of the transmission mechanism 20 in the vehicle front-rear direction. The drive shaft 4 is disposed in a position overlapping in the vehicle front-rear direction with the portion of the transmission gear unit 21 where the multiple gear trains G1-G6 are disposed, preferably at the center in the vehicle front-rear direction of the portion where the multiple gear trains G1-G6 are disposed. The drive shafts 4a, 4b extend linearly in the vehicle width direction perpendicular to the vehicle front-rear direction, and the drive shaft 4b on the right side of the vehicle extends in the vehicle width direction at the center of the transmission mechanism 20 in the vehicle front-rear direction.

The drive shaft 4 extends in the vehicle width direction at a position in the vehicle front-rear direction corresponding to a predetermined gear train G3 in which the vertical dimensions of the first gear and second gear are smallest among the multiple gear trains G1 to G6 of the shift gear unit 21, and is disposed in a position overlapping the predetermined gear train G3 in the vehicle front-rear direction. In this embodiment, the drive shaft 4 extends in the vehicle width direction at a position in the vehicle front-rear direction corresponding to the third-speed gear train G3, that is, at a position overlapping in the vehicle front-rear direction.

In this embodiment, the drive shaft 4 is provided in correspondence with the third-speed gear train G3, but it may also be provided in a position in the vehicle's fore-and-aft direction corresponding to the fourth-speed gear train G4. The drive shaft 4 is provided in a position in the vehicle's fore-and-aft direction corresponding to the medium-speed gear trains G3 and G4, which are predetermined gear trains in which the vertical dimensions of the first and second gears are small.

In the transmission 3, a 1st gear train G1 and a 2nd gear train are set as low-speed gear trains, a 5th gear train G5 and a 6th gear train G6 are set as high-speed gear trains, and a 3rd gear train G3 and a 4th gear train G4 are set as medium-speed gear trains.

When the 1st gear train to the 5th gear train are set as the forward gear train, the 1st gear train is set as the low gear train, the 5th gear train is set as the high gear train, and the 2nd gear train to the 4th gear train are set as the medium gear train, and the drive shaft 4 is provided at a position in the fore-and-aft direction of the vehicle body corresponding to the 2nd gear train to the 4th gear train, which are the medium gear trains, as the specified gear trains in which the vertical dimensions of the first and second gears are small.

When there are at least three or more gear trains as forward gear trains, the drive shaft 4 is provided at a vehicle longitudinal position corresponding to the medium gear train as a predetermined gear train in which the vertical dimensions of the first and second gears are small, and is preferably provided at a vehicle longitudinal position corresponding to the predetermined gear train in which the vertical dimensions of the first and second gears are smallest.

The transmission gear operating unit 22 is disposed above the transmission gear unit 21, as shown in FIG. 4. The transmission gear operating unit 22 includes a plurality of shift rods 61, 62, 63, 64 arranged in parallel to one another and supporting a plurality of shift forks 61a, 62a, 63a, 64a, respectively, a shift drum 65 having shift grooves 65a, 65b, 65c, 65d corresponding to the plurality of shift rods 61, 62, 63, 64, respectively, and a motor 66 as an actuator that rotates and drives the shift drum 65 to move the plurality of shift rods 61, 62, 63, 64.

The multiple shift rods 61, 62, 63, 64 of the transmission gear operating unit 22, specifically the four shift rods 61, 62, 63, 64, are arranged to extend in the fore-and-aft direction of the vehicle body above the drive shaft 4. Each shift rod 61, 62, 63, 64 extends linearly in the fore-and-aft direction of the vehicle body and is arranged to extend horizontally or substantially horizontally above the input shaft 30, the output shaft 40, and the counter shaft 50.

As shown in FIG. 8, starting from the left side of the vehicle body, four shift rods 61, 62, 63, and 64, specifically a first shift rod 61, a second shift rod 62, a third shift rod 63, and a fourth shift rod 64, are arranged in positions spaced apart in the vehicle width direction and overlap in the vehicle vertical direction.

The shift forks 61a, 62a, 63a, 64a supported by the shift rods 61, 62, 63, 64 extend downward from the shift rods 61, 62, 63, 64, respectively, and extend in a direction perpendicular to the vehicle front-rear direction. The multiple shift forks 61a, 62a, 63a, 64a are spaced apart in the vehicle front-rear direction, and the first shift fork 61a, the fourth shift fork 64a, the second shift fork 62a, and the third shift fork 63a are spaced apart in the vehicle front-rear direction, in that order from the front of the vehicle.

The shift arms 61b, 62b, 63b, and 64b supported by the shift rods 61, 62, 63, and 64 extend upward from the shift rods 61, 62, 63, and 64, respectively. The multiple shift arms 61b, 62b, 63b, and 64b are spaced apart in the front-rear direction of the vehicle body, and the protrusions 61c, 62c, 63c, and 64c at the tips of the shift arms 61b, 62b, 63b, and 64b are engaged with the shift grooves 65a, 65b, 65c, and 65d of the shift drum 65, respectively.

As shown in FIG. 7, the shift drum 65 and the motor 66 are disposed above the multiple shift rods 61, 62, 63, and 64 on the vehicle body rear side of the transmission mechanism 20. The shift drum 65 and the motor 66 are disposed so that their axes extend in the fore-and-aft direction of the vehicle body. The motor 66 is disposed above the shift drum 65.

As shown in FIG. 8, the drive shaft 4 extends in the vehicle width direction at a position overlapping the center of the transmission mechanism 20 in the vertical direction of the vehicle body. The drive shaft 4 extends in the vehicle width direction between the transmission gear unit 21 and the transmission gear operating unit 22 arranged above the transmission gear unit 21, specifically between the transmission gear unit 21 and the multiple shift rods 61, 62, 63, 64 of the transmission gear operating unit 22. The drive shaft 4 can be easily arranged between the transmission gear units 21 and the transmission gear operating units 22 that are distributed in the vertical direction of the vehicle body.

As shown in FIG. 7, the drive shaft 4 extends in the vehicle width direction between multiple shift forks 61a, 62a, 63a, and 64a. In the transmission 3, the drive shaft 4 extends in the vehicle width direction between a fourth shift fork 64a and a second shift fork 62a that are spaced apart in the vehicle front-rear direction.

In the vehicle 1, the transmission 3 is disposed near the drive shaft 4 at the rear of the vehicle body, and the drive shaft 4 extends in the vehicle width direction at the center of the vehicle front-rear direction and the center of the vehicle up-down direction of the speed change mechanism 20 of the transmission 3, and extends in the vehicle width direction by penetrating the transmission case 11. The drive shaft 4b on the right side of the vehicle body has a portion penetrating the side portion 11b on the right side of the vehicle body of the transmission case 11, and a portion of the drive shaft 4b located to the left of the part of the drive shaft 4b penetrates the side portion 11b on the left side of the vehicle body of the transmission case 11.

The drive shaft 4 also extends in the vehicle width direction between the transmission gear section 21 of the transmission mechanism 20 and the transmission gear operating section 22, and extends in the vehicle width direction at a position in the vehicle front-rear direction that corresponds to a specific gear train G3 in which the vertical dimensions of the first and second gears are small among the multiple gear trains G1 to G6 that make up the transmission gear section 21.

In this embodiment, the input shaft 30, the output shaft 40, and the countershaft 50 can be offset from each other in the vertical direction of the vehicle body, but are preferably arranged so as to overlap in the vertical direction of the vehicle body. The differential device 7 is arranged on the left side of the transmission 3, but can also be arranged on the right side of the transmission 3.

In addition, a motor 66 is used as an actuator for moving the multiple shift rods 61, 62, 63, 64, and an electric actuator is used, but an actuator such as a hydraulic actuator may be used to move the multiple shift rods 61, 62, 63, 64. In this embodiment, the transmission 3 is based on a manual transmission and uses an actuator to move the shift rods 61, 62, 63, 64, but it can also be applied to a manual transmission.

Thus, the power transmission device 5 of the vehicle according to this embodiment includes a transmission 3 that changes the speed of the power input from the drive source 2 and outputs it, and a drive shaft 4 that is connected to the transmission 3 and transmits the power from the drive source 2 output from the transmission 3 to the drive wheels 6. The transmission 3 has a speed change mechanism 20 that is arranged in a transmission case 11 with its axis extending in the fore-and-aft direction of the vehicle body and changes the speed of the power from the drive source 2. The drive shaft 4 extends in the vehicle width direction at the center of the transmission mechanism 20 in the vertical direction of the vehicle body, and is provided to pass through the transmission case 11.

As a result, when the transmission 3 is disposed near the drive shaft 4 at the rear of the vehicle body in a vehicle 1 equipped with a longitudinally mounted transmission 3, the drive shaft 4 extends in the vehicle width direction through the transmission case 11 at the center of the vertical direction of the vehicle body of the transmission mechanism 20, lowering the center of gravity of the vehicle and improving handling stability compared to when the transmission is disposed above the drive shaft. Also, compared to when the transmission is disposed below the drive shaft, the gap with the ground can be increased to ensure ground clearance.

Therefore, in a vehicle 1 equipped with a longitudinally mounted transmission 3, when the transmission 3 is disposed near the drive shaft 4 at the rear of the vehicle body, it is possible to improve the driving stability while ensuring sufficient ground clearance.

The transmission mechanism 20 also includes a transmission gear section 21 having an input shaft 30 and an output shaft 40 arranged on the same axis, a counter shaft 50 arranged parallel to the input shaft 30 and the output shaft 40, and a plurality of gear trains G1 to G6 each consisting of a first gear 31 to 36 provided on the input shaft 30 or the output shaft 40 and a second gear 41 to 46 provided on the counter shaft 50 and meshing with the first gear 31 to 36. The drive shaft 4 extends in the vehicle width direction at a position in the vehicle front-rear direction corresponding to a predetermined gear train G3 among the plurality of gear trains G1 to G6 in which the vertical dimensions of the first gear and the second gear are small.

This allows the drive shaft 4 to be positioned close to the axis of the transmission mechanism 20, allowing the transmission 3 and drive shaft 4 to be positioned compactly in the vertical direction of the vehicle body.

The transmission mechanism 20 also includes an input shaft 30 and an output shaft 40 arranged on the same axis, a counter shaft 50 arranged parallel to the input shaft 30 and the output shaft 40, a transmission gear section 21 having a plurality of gear trains G1 to G6 each consisting of a first gear 31 to 36 provided on the input shaft 30 or the output shaft 40 and a second gear 41 to 46 provided on the counter shaft 50 and meshing with the first gear 31 to 36, and a transmission gear operating section 22 that operates the transmission gear section 21. The drive shaft 4 extends in the vehicle width direction between the transmission gear section 21 and the transmission gear operating section 22.

As a result, compared to when the drive shaft extends in the vehicle width direction between the transmission gear units and between the transmission gear operating units, the drive shaft 4 can be easily arranged between the transmission gear units 21 and the transmission gear operating units 22, which are distributed in the vertical direction of the vehicle body, and the drive shaft 4 and the transmission 3 can be easily arranged.

The vehicle's power transmission device 5 also includes a differential device 7 that is connected to the transmission 3 and to the drive shaft 4 to transmit the power from the drive source 2 output from the transmission 3 to the drive shaft 4.

As a result, in a vehicle 1 equipped with a differential device 7 connected to a vertically mounted transmission 3 and a drive shaft 4, the drive shaft 4 extends in the vehicle width direction through the transmission case 11 at the center of the vehicle body in the vertical direction of the transmission mechanism 20, thereby improving handling stability while ensuring ground clearance.

The vehicle also includes a differential housing 14 that houses the differential device 7, and the differential housing 14 is formed integrally with the transmission case 11. This allows the differential housing 14 and the transmission case 11 to be formed more compactly than when the differential housing is not formed integrally with the transmission case 11 and is arranged in the vehicle width direction.

The present invention is not limited to the illustrated embodiments, and various improvements and design changes are possible without departing from the spirit of the present invention.

As described above, according to the present invention, when a longitudinally mounted transmission is disposed near the drive shaft at the rear of the vehicle, it is possible to improve the driving stability while maintaining ground clearance, and therefore the present invention may be suitably used in vehicles equipped with a longitudinally mounted transmission.

Reference Signs List 1 vehicle 2 engine 3 transmission 4 drive shaft 5 power transmission device 6 rear wheel 7 differential device 11 transmission case 14 differential housing 20 transmission mechanism section 21 transmission gear section 22 transmission gear operation section 30 input shaft 31-36 first gear 40 output shaft 41-46 second gear 50 counter shaft G1-G6 gear train

Claims (4)

A power transmission device for a vehicle including a transmission that changes the speed of power input from a drive source and outputs the power, and a drive shaft that is connected to the transmission and transmits the power from the drive source output from the transmission to a drive wheel,
the transmission has a transmission mechanism disposed in a transmission case with an axis extending in the front-rear direction of the vehicle body and configured to change the speed of power from the drive source,
the drive shaft extends in a vehicle width direction at a center side of the transmission mechanism in the vehicle body vertical direction and penetrates the transmission case ,
the speed change mechanism includes an input shaft and an output shaft arranged on the same axis, a counter shaft arranged in parallel with the input shaft and the output shaft, a speed change gear unit having a plurality of gear trains each including a first gear provided on the input shaft or the output shaft and a second gear provided on the counter shaft and meshing with the first gear, and a speed change gear operating unit that operates the speed change gear unit,
The drive shaft extends in a vehicle width direction between the transmission gear unit and the transmission gear operation unit .
A power transmission device for a vehicle. the drive shaft extends in the vehicle width direction at a position in the vehicle front-rear direction corresponding to a predetermined gear train in which the first gear and the second gear have small vertical dimensions among the plurality of gear trains;
2. The power transmission device for a vehicle according to claim 1. a differential device connected to the transmission and to the drive shaft for transmitting the power from the drive source output from the transmission to the drive shaft;
3. A power transmission device for a vehicle according to claim 1 or 2 . a differential housing in which the differential device is housed,
The differential housing is integrally formed with the transmission case.
4. The power transmission device for a vehicle according to claim 3 .

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