Patent Description:
In a vehicle such as an automobile, a transmission and a differential device are provided in a motive power transmission path from a drive source such as an engine to drive wheels, and motive power from the drive source is transmitted to a drive shaft extending from the differential device in a vehicle width direction via the transmission and the differential device and is transmitted from the drive shaft to the drive wheels.

In a vehicle including a longitudinal placement type transmission for a front-engine/rear-drive vehicle, an engine and the transmission are arranged in a vehicle-body front portion, and motive power from the engine is transmitted from the transmission to a rear-wheel differential device arranged in a vehicle-body rear portion through a propeller shaft and is transmitted to rear wheels via a drive shaft.

Further, in a vehicle including a longitudinal placement type transmission for a front-engine/rear-drive based four-wheel drive vehicle, a transfer device is provided which distributes motive power from an engine, which is output from the transmission, also to front wheels, and the motive power from the engine is transmitted from the transfer device to a front-wheel differential device arranged in a vehicle-body front portion through a propeller shaft for front wheels and is transmitted also to the front wheels via a drive shaft.

For example, Patent Literature <NUM> discloses that in a vehicle including a longitudinal placement type transmission for a front-engine/rear-drive based four-wheel drive vehicle, a drive shaft extending in a vehicle width direction is arranged on a vehicle front side of a transmission such as a continuously variable transmission arranged in a vehicle-body front portion and on a vehicle rear side of a starting clutch.

[Patent Literature <NUM>] National Publication of International Patent Application No.<CIT>.

<CIT> describes a transmission for motor vehicles having a conical-disc band transmission placed in a casing, a reduction gear and, if necessary, a differential.

There may be a case where in a vehicle such as a sports type front-engine/rear-drive vehicle, a drive source such as an engine is arranged in a vehicle-body front portion, and a longitudinal placement type transmission is arranged in the vicinity of a drive shaft in a vehicle-body rear portion for the purpose of an increase in a weight of the vehicle-body rear portion or the like. In such a case, motive power is transmitted from the drive source to the transmission via a propeller shaft, and the motive power is transmitted from the transmission to drive wheels arranged in the vehicle-body rear portion via a differential device and the drive shaft which are arranged in the vehicle-body rear portion.

In the vehicle, in a case where the transmission arranged in the vehicle-body rear portion is arranged on a vehicle front side of the drive shaft, a vehicle cabin space becomes narrow, and comfortability of an occupant might thereby be lowered. To handle this, although it is possible to arrange the transmission on a vehicle rear side of the drive shaft, an overhang on the vehicle rear side becomes large and may cause lowering of operation stability.

Accordingly, an object of the present invention is to achieve both of comfortability of an occupant and operation stability in a case where a transmission is arranged in the vicinity of a drive shaft in a vehicle-body rear portion in a vehicle including a longitudinal placement type transmission.

The present invention provides a motive power transmission device as defined in claim <NUM>.

According to the present invention, in a case where a transmission is arranged in the vicinity of a drive shaft in a vehicle-body rear portion in a vehicle including a longitudinal placement type transmission (or a longitudinally mounted transmission), because the drive shaft extends in the vehicle width direction on a central side of the transmission mechanism unit in the vehicle front-rear direction such that the drive shaft passes through the transmission casing, lowering of comfortability of an occupant due to narrowing of a vehicle cabin space by the transmission can be inhibited compared to a case where the transmission is arranged on a vehicle front side of the drive shaft. Further, lowering of operation stability due to enlargement of an overhang on a vehicle rear side can be inhibited compared to a case where the transmission is arranged on the vehicle rear side of the drive shaft.

Consequently, in a case where the transmission is arranged in the vicinity of the drive shaft in the vehicle-body rear portion in the vehicle including the longitudinal placement type transmission, both of comfortability of an occupant and operation stability can be achieved.

The drive shaft particularly extends in the vehicle width direction on a central side of the transmission mechanism unit in a vehicle up-down direction.

With this configuration, because the drive shaft extends in the vehicle width direction on a central side of the transmission mechanism unit in the vehicle up-down direction, the position of the center of gravity of the vehicle is lowered compared to a case where the transmission is arranged above the drive shaft, and operation stability can thereby be improved. Further, compared to a case where the transmission is arranged below the drive shaft, a gap from a ground surface is increased, and a ground clearance can thereby be secured.

The transmission mechanism unit includes an input shaft and an output shaft that are arranged on the same axis line, a counter shaft that is arranged in parallel with the input shaft and the output shaft, and a transmission gear unit that has plural gear trains each of which is formed with a first gear provided to the input shaft or the output shaft and a second gear provided to the counter shaft and meshing with the first gear, and the drive shaft particularly extends in the vehicle width direction in a position, in the vehicle front-rear direction, corresponding to a predetermined gear train of which the first gear and the second gear have small dimensions in an up-down direction among the plural gear trains.

With this configuration, because the drive shaft extends in the vehicle width direction in a position, in the vehicle front-rear direction, corresponding to the predetermined gear train of which the first gear and the second gear have small dimensions in the up-down direction among the plural gear trains, the drive shaft is arranged close to the axis line of the transmission mechanism unit, and the transmission and the drive shaft can thereby compactly be arranged in the vehicle up-down direction.

The transmission mechanism unit particularly includes an input shaft and an output shaft that are arranged on the same axis line, a counter shaft that is arranged in parallel with the input shaft and the output shaft, a transmission gear unit that has plural gear trains each of which is formed with a first gear provided to the input shaft or the output shaft and a second gear provided to the counter shaft and meshing with the first gear, and a transmission gear operation unit that operates the transmission gear unit, and the drive shaft particularly extends in the vehicle width direction through a portion between the transmission gear unit and the transmission gear operation unit.

With this configuration, the drive shaft extends in the vehicle width direction through a portion between the transmission gear unit and the transmission gear operation unit. Thus, compared to a case where the drive shaft extends in the vehicle width direction through a portion in the transmission gear unit and a portion in the transmission gear operation unit, the drive shaft can be arranged with high assemblability between the transmission gear unit and the transmission gear operation unit that are dispersedly arranged in the vehicle up-down direction. The drive shaft and the transmission can thereby be arranged with high assemblability.

The motive power transmission device for a vehicle includes a differential device that is coupled with the transmission and coupled with the drive shaft and transmits the motive power from the drive source, which is output from the transmission, to the drive shaft.

With this configuration, in a vehicle including a differential device that is coupled with a longitudinal placement type transmission (or a longitudinally mounted transmission) and coupled with a drive shaft, the drive shaft extends in the vehicle width direction on a central side of the transmission mechanism unit in the vehicle front-rear direction such that the drive shaft passes through the transmission casing, and both of comfortability of an occupant and operation stability can thereby be achieved.

The motive power transmission device for a vehicle particularly includes a differential housing in which the differential device is housed, and the differential housing is particularly integrally formed with the transmission casing.

With this configuration, because the differential housing is integrally formed with the transmission casing, compared to a case where the differential housing is arranged in the vehicle width direction without being integrally formed with the transmission casing, the differential housing and the transmission casing can compactly be formed.

Particularly, the drive shaft extends in the vehicle width direction through a portion between the transmission gear unit and plural shift rods of the transmission gear operation unit.

Further particularly, the drive shaft extends in the vehicle width direction through a portion among plural shift forks, which are separately arranged in the vehicle front-rear direction, in the transmission.

Further particularly, the plural shift forks include a first shift fork, a second shift fork, a third shift fork, and a fourth shift fork.

Further particularly, the second shift fork and the fourth shift fork are located between the first shift fork and the third shift fork, in the vehicle front-rear direction.

Further particularly, the drive shaft extends in the vehicle width direction through a portion between the fourth shift fork and the second shift fork which are separately arranged in the vehicle front-rear direction.

Further particularly, the transmission casing includes a bottom surface portion, side face portions on both sides in the vehicle width direction, and a top face portion.

Further particularly, the side face portion on the vehicle left side is integrally formed with the differential housing and is provided with a shaft insertion portion through which the drive shaft extending from the differential device to a vehicle right side is inserted.

Further particularly, the side face portion on the vehicle right side is also provided with a shaft insertion portion through which the drive shaft is inserted.

Further particularly, the drive shaft passes through the transmission casing through the shaft insertion portions and extends in the vehicle width direction.

Further particularly, a vehicle includes the above motive power transmission device.

According to the present invention, in a case where a transmission is arranged in the vicinity of a drive shaft in a vehicle-body rear portion in a vehicle including a longitudinal placement type transmission, both of comfortability of an occupant and operation stability can be achieved.

An embodiment of the present invention will hereinafter be described with reference to the attached drawings. All of the features as shown in the drawings may not necessarily be essential.

<FIG> is a schematic diagram of a vehicle including a motive power transmission device according to the embodiment of the present invention. As illustrated in <FIG>, a vehicle (or automobile) <NUM> is particularly a vehicle as a front-engine/rear-drive vehicle of a sports type or the like in which a seated position of a driver seat is low and the position of the center of gravity is low, an engine <NUM> as a drive source is arranged in a vehicle-body front portion, and a longitudinal placement type transmission <NUM> is arranged in the vicinity of a drive shaft <NUM> extending in a vehicle width direction in a vehicle-body rear portion.

A motive power transmission device <NUM> according to the present embodiment particularly includes, in a motive power transmission path from the engine <NUM> to rear wheels <NUM> as drive wheels, the transmission <NUM> outputting motive power input from the engine <NUM> while performing gear-shifting for the motive power and the drive shaft <NUM> coupled with the transmission <NUM> and transmitting the motive power from the engine <NUM>, which is output from the transmission <NUM>, to the rear wheels <NUM> in the vehicle-body rear portion and includes a differential device <NUM> coupled with the transmission <NUM>, coupled with the drive shaft <NUM>, and transmitting the motive power from the engine <NUM>, which is output from the transmission <NUM>, to the drive shaft <NUM>.

The motive power from the engine <NUM> is particularly transmitted to the transmission <NUM> via a propeller shaft <NUM> extending in a vehicle front-rear direction and is transmitted from the transmission <NUM> to left and right rear wheels <NUM> via the differential device <NUM> and the drive shaft <NUM>.

In the vehicle <NUM>, a tunnel portion 10a bulging to a vehicle upper side is particularly formed to extend in the vehicle front-rear direction on a central side, in the vehicle width direction, of a floor panel <NUM> configuring a bottom surface of a vehicle cabin <NUM>, and the propeller shaft <NUM> is arranged in a space on the inside of the tunnel portion 10a. A vehicle front side of the transmission <NUM> to be coupled with the propeller shaft <NUM> is also arranged in the tunnel portion 10a.

<FIG> is a perspective view of the motive power transmission device. As illustrated in <FIG>, the transmission <NUM> is arranged in the vicinity of the drive shaft <NUM>. As described later, the transmission <NUM> particularly has a transmission mechanism unit <NUM> which is arranged in a transmission casing <NUM> such that its axis line extends in the vehicle front-rear direction and which performs gear-shifting for the motive power from the engine <NUM>. The transmission casing <NUM> is formed in a generally tubular shape and extends in the vehicle front-rear direction, a vehicle front side thereof is particularly covered by a front-side housing <NUM>, and a vehicle rear side thereof is particularly covered by a rear-side housing <NUM>.

The differential device <NUM> is particularly arranged on a vehicle left side as one vehicle-width-direction side of the transmission <NUM>. The drive shaft <NUM> respectively extending to both sides in the vehicle width direction is particularly coupled with the differential device <NUM>. A differential housing <NUM> in which the differential device <NUM> is housed is particularly arranged on the vehicle left side of the transmission casing <NUM> and is integrally formed with the transmission casing <NUM>.

The differential housing <NUM> includes a first housing <NUM> which particularly configures a vehicle right side as the other vehicle-width-direction side of the differential housing <NUM> and particularly houses a vehicle right side of the differential device <NUM> and a second housing <NUM> which particularly configures a vehicle left side of the differential housing <NUM> and particularly houses a vehicle left side of the differential device <NUM>.

Particularly, the first housing <NUM> is integrally molded with the transmission casing <NUM>, the second housing <NUM> is fixed to the first housing <NUM> by using fastening bolts, and the differential housing <NUM> is thereby integrally formed with the transmission casing <NUM>. The second housing <NUM> is particularly provided with a shaft insertion portion 16a through which a drive shaft 4a extending from the differential device <NUM> to a vehicle left side is inserted.

The transmission casing <NUM> particularly includes a bottom surface portion 11a, side face portions 11b on both sides in the vehicle width direction, and a top face portion 11c. Particularly, as illustrated in <FIG>, the side face portion 11b on the vehicle left side is integrally formed with the first housing <NUM> and is provided with a shaft insertion portion 11d through which a drive shaft 4b extending from the differential device <NUM> to a vehicle right side is inserted. Further particularly, the side face portion 11b on the vehicle right side is also provided with a shaft insertion portion 11e through which the drive shaft 4b is inserted. The drive shaft 4b particularly passes through the transmission casing <NUM> through the shaft insertion portions 11d and 11e and extends in the vehicle width direction.

<FIG> is a skeleton diagram of the motive power transmission device. As illustrated in <FIG>, the transmission <NUM> is particularly configured to be capable of achieving forward six speeds and reverse one speed. The transmission <NUM> has the transmission mechanism unit <NUM> which performs gear-shifting for the motive power from the engine <NUM>.

The transmission mechanism unit <NUM> particularly includes, in the transmission casing <NUM>, an input shaft <NUM> to which an output from the engine <NUM> is input via a clutch (not illustrated), an output shaft which is particularly arranged on the same axis line as the input shaft <NUM> and outputs the motive power from the engine <NUM>, and a counter shaft <NUM> arranged in parallel with the input shaft <NUM> and the output shaft <NUM>. Each of the input shaft <NUM>, the output shaft <NUM>, and the counter shaft <NUM> is arranged such that its axis line extends in the vehicle front-rear direction.

The input shaft <NUM> is rotatably supported by the transmission casing <NUM> via a bearing <NUM>. The output shaft <NUM> is rotatably supported by the transmission casing <NUM> via a bearing <NUM>. Particularly, a rear end portion of the input shaft <NUM> is rotatably fitted on a front end portion of the output shaft <NUM>. The counter shaft <NUM> is rotatably supported by the transmission casing <NUM> via a bearing <NUM>.

A driving gear <NUM> particularly for a fourth speed stage (or a fourth gear) is fixedly provided to a vehicle front side of the input shaft <NUM>. On the output shaft <NUM>, in order from the vehicle front side, a driven gear <NUM> particularly for a sixth speed stage (or a sixth gear), a driven gear <NUM> particularly for a fifth speed stage (or a fifth gear), a driven gear <NUM> particularly for a second speed stage (or a second gear), a driven gear <NUM> particularly for a third speed stage (or a third gear), a driven gear <NUM> particularly for a first speed stage (or a first gear), and a driven gear <NUM> particularly for a reverse speed stage (or a reverse gear) are loosely fit.

To the counter shaft <NUM>, in order from the vehicle front side, a driven gear <NUM> particularly for the fourth speed stage, a driving gear <NUM> particularly for the sixth speed stage, a driving gear <NUM> particularly for the fifth speed stage, a driving gear <NUM> particularly for the second speed stage, a driving gear <NUM> particularly for the third speed stage, a driving gear <NUM> particularly for the first speed stage, and a driving gear <NUM> particularly for the reverse speed stage are fixedly provided.

A gear train G4 particularly for the fourth speed stage is configured with the driving gear <NUM> for the fourth speed and the driven gear <NUM> for the fourth speed stage which always meshes with the driving gear <NUM> for the fourth speed stage. When a shift lever is operated to a fourth speed, the input shaft <NUM> and the output shaft <NUM> are directly coupled together, and the fourth speed is thereby achieved. The gear train G4 for the fourth speed stage functions as a reduction gear train which transmits rotation of the input shaft <NUM> to the counter shaft <NUM> while reducing the speed of the rotation at a specific reduction ratio.

Further, a gear train G1 particularly for the first speed stage, a gear train G2 particularly for the second speed stage, a gear train G3 particularly for the third speed stage, a gear train G5 particularly for the fifth speed stage, and a gear train G6 particularly for the sixth speed stage are respectively configured with: the driven gear <NUM> for the first speed stage, the driven gear <NUM> for the second speed stage, the driven gear <NUM> for the third speed stage, the driven gear <NUM> for the fifth speed stage, and the driven gear <NUM> for the sixth speed stage; and the driving gear <NUM> for the first speed stage, the driving gear <NUM> for the second speed stage, the driving gear <NUM> for the third speed stage, the driving gear <NUM> for the fifth speed stage, and the driving gear <NUM> for the sixth speed stage which always respectively mesh with the driven gear <NUM> for the first speed stage, the driven gear <NUM> for the second speed stage, the driven gear <NUM> for the third speed stage, the driven gear <NUM> for the fifth speed stage, and the driven gear <NUM> for the sixth speed stage.

As for the driving gear <NUM> for the fourth speed stage which is provided to the input shaft <NUM>, the driven gear <NUM> for the first speed stage, the driven gear <NUM> for the second speed stage, the driven gear <NUM> for the third speed stage, the driven gear <NUM> for the fifth speed stage, and the driven gear <NUM> for the sixth speed stage which are provided to the output shaft <NUM>, a gear diameter as an outer diameter of a gear is particularly formed smaller as a shift stage becomes higher.

As for the driving gear <NUM> for the first speed stage, the driving gear <NUM> for the second speed stage, the driving gear <NUM> for the third speed stage, the driven gear <NUM> for the fourth speed stage, the driving gear <NUM> for the fifth speed stage, and the driving gear <NUM> for the sixth speed stage which are provided to the counter shaft <NUM>, the gear diameter is particularly formed larger as the shift stage becomes higher.

In the transmission <NUM>, as for the gear train G3 for the third speed stage and the gear train G4 for the fourth speed stage as gear trains for intermediate speed stages among the gear train G1 for the first speed stage to the gear train G6 for the sixth speed stage, their maximum gear diameters among the gear diameters of sets of two gears configuring the gear trains are particularly formed to be small compared to the gear train G1 for the first speed stage and the gear train G2 for the second speed stage as gear trains for low speed stages and the gear train G5 for the fifth speed stage and the gear train G6 for the sixth speed stage as gear trains for high speed stages. Among the gear train G1 for the first speed stage to the gear train G6 for the sixth speed stage, as for the gear train G3 for the third speed stage, its maximum gear diameters are particularly formed to be smallest among the gear diameters of sets of two gears configuring the gear trains.

Particularly, the driven gear <NUM> for the reverse speed stage and the driving gear <NUM> for the reverse speed stage do not mesh with each other but always mesh with an idler gear for the reverse speed stage which is loosely fitted on a reverse shaft disposed in parallel with the input shaft <NUM>, the output shaft <NUM>, and the counter shaft <NUM> in the transmission casing <NUM>. A gear train GR for the reverse speed stage is particularly configured with the driven gear <NUM> for the reverse speed stage, the driving gear <NUM> for the reverse speed stage, and the idler gear for the reverse speed stage.

The transmission mechanism unit <NUM> particularly includes a transmission gear unit <NUM> having plural gear trains each of which is formed with a first gear provided to the input shaft <NUM> or the output shaft <NUM> and a second gear provided to the counter shaft <NUM> and meshing with the first gear. The driven gear <NUM> for the first speed stage, the driven gear <NUM> for the second speed stage, the driven gear <NUM> for the third speed stage, the driving gear <NUM> for the fourth speed stage, the driven gear <NUM> for the fifth speed stage, and the driven gear <NUM> for the sixth speed stage configure first gears <NUM> to <NUM>. The driving gear <NUM> for the first speed stage, the driving gear <NUM> for the second speed stage, the driving gear <NUM> for the third speed stage, the driven gear <NUM> for the fourth speed stage, the driving gear <NUM> for the fifth speed stage, and the driving gear <NUM> for the sixth speed stage configure second gears <NUM> to <NUM>. The gear train G1 for the first speed stage to the gear train G6 for the sixth speed stage configure plural gear trains G1 to G6 each of which is formed with the first gear and the second gear.

In addition, a first dog clutch <NUM> is particularly provided on a vehicle front side of the driven gear <NUM> for the sixth speed stage, a second dog clutch <NUM> is particularly provided between the driven gear <NUM> for the fifth speed stage and the driven gear <NUM> for the second speed stage, a third dog clutch <NUM> is particularly provided between the driven gear <NUM> for the third speed stage and the driven gear <NUM> for the first speed stage, and a fourth dog clutch <NUM> is particularly provided on a vehicle front side of the driven gear <NUM> for the reverse speed stage. The dog clutches <NUM>, <NUM>, <NUM>, and <NUM> are formed generally similarly.

The first dog clutch <NUM> particularly has a disk-shaped clutch ring 51a which is coupled with the output shaft <NUM> to be incapable of relative rotation thereto and provided to be capable of relative movement in an axis line direction of the output shaft <NUM>. Plural clutch teeth 51b protruding in the axis line direction of the output shaft <NUM> are particularly provided on a surface of the clutch ring 51a on the vehicle front side. The plural clutch teeth 51b radially extend in radial directions of the output shaft <NUM> and are particularly arranged at equivalent intervals in a circumferential direction of the output shaft <NUM>.

The driving gear <NUM> for the fourth speed stage is particularly provided with plural clutch teeth 31a which protrude in the axis line direction of the output shaft <NUM> while corresponding to the plural clutch teeth 51b of the clutch ring 51a. The plural clutch teeth 31a radially extend in the radial directions of the output shaft <NUM> and are arranged at equivalent intervals in the circumferential direction of the output shaft <NUM>.

The clutch teeth 51b and the clutch teeth 31a are particularly formed to be engaged together when the clutch ring 51a is moved toward the driving gear <NUM> for the fourth speed stage. When the clutch teeth 51b and the clutch teeth 31a are engaged together and the clutch ring 51a is engaged with the driving gear <NUM> for the fourth speed stage, the input shaft <NUM> and the output shaft <NUM> are directly coupled together, and rotation of the input shaft <NUM> is transmitted to the output shaft <NUM>.

Plural clutch teeth 51c protruding in the axis line direction of the output shaft <NUM> are particularly provided on a surface of the clutch ring 51a on the vehicle rear side, and the plural clutch teeth 51c radially extend in the radial directions of the output shaft <NUM> and are arranged at equivalent intervals in the circumferential direction of the output shaft <NUM>.

The driven gear <NUM> for the sixth speed stage is particularly provided with plural clutch teeth 32a which protrude in the axis line direction of the output shaft <NUM> while corresponding to the plural clutch teeth 51c of the clutch ring 51a, and the plural clutch teeth 32a radially extend in the radial directions of the output shaft <NUM> and are arranged at equivalent intervals in the circumferential direction of the output shaft <NUM>.

The clutch teeth 51c and the clutch teeth 32a are particularly formed to be engaged together when the clutch ring 51a is moved toward the driven gear <NUM> for the sixth speed stage. When the clutch teeth 51c and the clutch teeth 32a are engaged together and the clutch ring 51a is engaged with the driven gear <NUM> for the sixth speed stage, the gear train G6 for the sixth speed stage is set to a motive power transmission state. The driven gear <NUM> for the sixth speed stage and the output shaft <NUM> are coupled together, and rotation of the input shaft <NUM> is transmitted to the counter shaft <NUM> by the gear train G4 for a speed reduction stage and is transmitted to the output shaft <NUM> by the gear train G6 for the sixth speed stage.

In the second dog clutch <NUM>, plural clutch teeth 52b are particularly provided to a surface of a clutch ring 52a on the vehicle front side, and plural clutch teeth 52c are provided to a surface on the vehicle rear side.

The driven gear <NUM> for the fifth speed stage is particularly provided with plural clutch teeth 33a which correspond to the plural clutch teeth 52b of the clutch ring 52a. The driven gear <NUM> for the second speed stage is particularly provided with plural clutch teeth 34a which correspond to the plural clutch teeth 52c of the clutch ring 52a.

The clutch teeth 52b and the clutch teeth 33a are particularly formed to be engaged together when the clutch ring 52a is moved toward the driven gear <NUM> for the fifth speed stage. The clutch teeth 52c and the clutch teeth 34a are particularly formed to be engaged together when the clutch ring 52a is moved toward the driven gear <NUM> for the second speed stage.

When the clutch ring 52a is engaged with the driven gear <NUM> for the fifth speed stage, the gear train G5 for the fifth speed stage is set to the motive power transmission state, and rotation of the input shaft <NUM> is transmitted to the output shaft <NUM> via the gears G4 for the speed reduction stage and the gear train G6 for the sixth speed stage. When the clutch ring 52a is engaged with the driven gear <NUM> for the second speed stage, the gear train G2 for the second speed stage is set to the motive power transmission state, and rotation of the input shaft <NUM> is transmitted to the output shaft <NUM> via the gears G4 for the speed reduction stage and the gear train G2 for the second speed stage.

In the third dog clutch <NUM>, plural clutch teeth 53b are particularly provided to a surface of a clutch ring 53a on the vehicle front side, and plural clutch teeth 53c are particularly provided to a surface on the vehicle rear side.

The driven gear <NUM> for the third speed stage is particularly provided with plural clutch teeth 35a which correspond to the plural clutch teeth 53b of the clutch ring 53a. The driven gear <NUM> for the first speed stage is particularly provided with plural clutch teeth 36a which correspond to the plural clutch teeth 53c of the clutch ring 53a.

The clutch teeth 53b and the clutch teeth 35a are particularly formed to be engaged together when the clutch ring 53a is moved toward the driven gear <NUM> for the third speed stage. The clutch teeth 53c and the clutch teeth 36a are formed to be engaged together when the clutch ring 53a is moved toward the driven gear <NUM> for the first speed stage.

When the clutch ring 53a is engaged with the driven gear <NUM> for the third speed stage, the gear train G3 for the third speed stage is set to the motive power transmission state, and rotation of the input shaft <NUM> is transmitted to the output shaft <NUM> via the gears G4 for the speed reduction stage and the gear train G3 for the third speed stage. When the clutch ring 53a is engaged with the driven gear <NUM> for the first speed stage, the gear train G1 for the first speed stage is set to the motive power transmission state, and rotation of the input shaft <NUM> is transmitted to the output shaft <NUM> via the gears G4 for the speed reduction stage and the gear train G1 for the first speed stage.

In the fourth dog clutch <NUM>, plural clutch teeth 54b are particularly provided to a surface of a clutch ring 54a on the vehicle front side. The driven gear <NUM> for the reverse speed stage is particularly provided with plural clutch teeth 37a which correspond to the plural clutch teeth 54b of the clutch ring 54a. The clutch teeth 54b and the clutch teeth 37a are particularly formed to be engaged together when the clutch ring 54a is moved toward the driven gear <NUM> for the reverse speed stage.

When the clutch ring 54a is engaged with the driven gear <NUM> for the reverse speed stage, the gear train GR for the reverse speed stage is set to the motive power transmission state, and rotation of the input shaft <NUM> is transmitted to the output shaft <NUM> via the gears G4 for the speed reduction stage and the gear train GR for the reverse speed stage.

The transmission mechanism unit <NUM> further includes a transmission gear operation unit <NUM> for operating the transmission gear unit <NUM>. The transmission gear operation unit <NUM> particularly includes plural shift rods <NUM>, <NUM>, <NUM>, and <NUM> linearly extending in the vehicle front-rear direction, and the plural shift rods <NUM>, <NUM>, <NUM>, and <NUM> respectively support plural shift forks 61a, 62a, 63a, and 64a and are particularly arranged in parallel with each other.

The transmission <NUM> particularly includes, in order from the vehicle left side, the first shift rod <NUM>, the second shift rod <NUM>, the third shift rod <NUM>, and the fourth shift rod <NUM>. The first shift rod <NUM>, the second shift rod <NUM>, the third shift rod <NUM>, and the fourth shift rod <NUM> respectively support the first shift fork 61a, the second shift fork 62a, the third shift fork 63a, and the fourth shift fork 64a which are respectively engaged with the clutch rings 51a, 53a, 54a, and 52a.

Particularly, outer peripheral portions of the clutch rings 51a, 53a, 54a, and 52a are respectively accommodated in recesses provided to distal end portions of the shift forks 61a, 63a, 64a, and 62a, and the clutch rings 51a, 53a, 54a, and 52a are respectively moved in the axis line direction of the output shaft <NUM> by movement of the shift forks 61a, 63a, 64a, and 62a.

Particularly, the transmission gear operation unit <NUM> further includes a shift drum <NUM> which has shift grooves 65a, 65b, 65c, and 65d corresponding to the shift rods <NUM>, <NUM>, <NUM>, and <NUM> and a motor <NUM> as an actuator which causes the shift drum <NUM> to be driven to rotate and causes the plural shift rods <NUM>, <NUM>, <NUM>, and <NUM> to be operated to move.

The shift drum <NUM> is particularly formed in a cylindrical shape, and in its outer peripheral surface, the first shift groove 65a, the second shift groove 65b, the third shift groove 65c, and the fourth shift groove 65d are formed while corresponding to the first shift rod <NUM>, the second shift rod <NUM>, the third shift rod <NUM>, and the fourth shift rod <NUM>.

Particularly, projection portions 61c, 62c, 63c, and 64c are respectively engaged with the first shift groove 65a, the second shift groove 65b, the third shift groove 65c, and the fourth shift groove 65d, the projection portions 61c, 62c, 63c, and 64c being provided to distal end portions of a first shift arm 61b, a second shift arm 62b, a third shift arm 63b, and a fourth shift arm 64b which are respectively fixed to and supported by the first shift rod <NUM>, the second shift rod <NUM>, the third shift rod <NUM>, and the fourth shift rod <NUM>.

The motor <NUM> particularly causes the shift drum <NUM> to be driven to rotate based on an operation of the shift lever and thereby causes the plural shift rods <NUM>, <NUM>, <NUM>, and <NUM> to be operated to move. When the shift drum <NUM> is driven to rotate by the motor <NUM>, the shift rods <NUM>, <NUM>, <NUM>, and <NUM> are selectively operated to move in the axis line direction via the shift arms 61b, 62b, 63b, and 64b in accordance with the shift grooves 65a, 65b, 65c, and 65d.

Then, the shift forks 61a, 62a, 63a, and 64a supported by the shift rods <NUM>, <NUM>, <NUM>, and <NUM> are moved, and the dog clutches <NUM>, <NUM>, <NUM>, and <NUM> are selectively operated. Accordingly, changes such as shift-up, shift-down, and reverse are performed by an operation of the shift lever, and forward six speeds and reverse one speed are thereby achieved.

Particularly, in the transmission <NUM>, on the output shaft <NUM>, an output gear <NUM> is fixedly provided to a vehicle rear side of the driven gear <NUM> for the reverse speed stage, and the output gear <NUM> meshes with an input gear <NUM> fixedly provided to a vehicle rear side of a drive pinion <NUM> extending in the vehicle front-rear direction. The drive pinion <NUM> is rotatably supported by the transmission casing <NUM>. The motive power from the engine <NUM> which is output from the transmission <NUM> is transmitted to the differential device <NUM> via the drive pinion <NUM>.

The differential device <NUM> particularly has a differential casing <NUM> rotatably supported by the differential housing <NUM> and a ring gear <NUM> fixed to the differential casing <NUM>. The ring gear <NUM> meshes with the drive pinion <NUM> and is arranged on the vehicle left side of the drive pinion <NUM>.

The differential device <NUM> further has a differential mechanism <NUM>. The differential mechanism <NUM> particularly has a pinion shaft 29a fixed to the differential casing <NUM> and extending in a direction orthogonal to the vehicle width direction, a pair of pinion gears 29b which are rotatably fitted on the pinion shaft 29a and are opposed to each other, and a pair of left and right side gears 29c meshing with the pair of pinion gears 29b.

The drive shaft <NUM> extending in the vehicle width direction is particularly spline-fitted in the pair of side gears 29c. The drive shaft <NUM> is, together with the side gears 29c, capable of relative rotation to the differential housing <NUM> and the differential casing <NUM>. The left rear wheel <NUM> is coupled with the drive shaft 4a, and the right rear wheel <NUM> is coupled with the drive shaft 4b.

The differential device <NUM> is coupled with the transmission <NUM> and also coupled with the drive shaft <NUM> and transmits the motive power from the engine <NUM>, which is output from the transmission <NUM>, to the drive shaft <NUM>, and the drive shaft <NUM> is coupled with the transmission <NUM> via the drive pinion <NUM> and the differential device <NUM> and transmits the motive power from the engine <NUM>, which is output from the transmission <NUM>, to the rear wheels <NUM>.

In the present embodiment, the drive shaft <NUM> extends in the vehicle width direction on a central side of the transmission mechanism unit <NUM> of the transmission <NUM> in the vehicle front-rear direction. The drive shaft <NUM> is particularly arranged in a position, in the vehicle front-rear direction, overlapping with a portion, in the vehicle front-rear direction, in which the plural gear trains G1 to G6 of the transmission gear unit <NUM> are arranged. The drive shaft <NUM> also extends in the vehicle width direction in a position, in a vehicle up-down direction, overlapping with the transmission mechanism unit <NUM> on a central side of the transmission mechanism unit <NUM> of the transmission <NUM> in the vehicle up-down direction.

Next, the motive power transmission device according to the embodiment of the present invention will further be described with reference to <FIG>.

<FIG> is a perspective view of the transmission and the differential device, <FIG> is a top view of the transmission, the differential device, and the drive shaft, <FIG> is a top view of the transmission gear unit of the transmission, <FIG> is a side view of the transmission gear operation unit of the transmission as seen from Y7 direction in <FIG>, and <FIG> is a side view of the transmission mechanism unit of the transmission as seen from Y7 direction in <FIG>. <FIG> are drawings in which the transmission casing and the differential housing are removed. The drive shaft is illustrated in <FIG>.

As illustrated in <FIG>, the transmission <NUM> particularly has the transmission mechanism unit <NUM> which is particularly arranged in the vicinity of the drive shaft <NUM> and is particularly arranged in the transmission casing <NUM> such that the axis line extends in the vehicle front-rear direction. The transmission mechanism unit <NUM> includes the input shaft <NUM>, the output shaft <NUM>, and the counter shaft <NUM>, the transmission gear unit <NUM> having the plural gear trains G1 to G6 which are respectively formed with the first gears <NUM> to <NUM> provided to the input shaft <NUM> or the output shaft <NUM> and the second gears <NUM> to <NUM> provided to the counter shaft <NUM>, and the transmission gear operation unit <NUM> for operating the transmission gear unit <NUM>.

The differential device <NUM> is particularly arranged on a vehicle left side of the transmission <NUM>, the motive power from the engine <NUM> which is output from the transmission <NUM> is transmitted to the differential device <NUM> via the drive pinion <NUM> extending in the vehicle front-rear direction, and the differential device <NUM> transmits the transmitted motive power from the engine <NUM> to the drive shaft <NUM> extending in the vehicle width direction. The left and right drive shafts <NUM> respectively transmit the transmitted motive power from the engine <NUM> to the left and right rear wheels <NUM>.

Particularly, As illustrated in <FIG>, in the transmission gear unit <NUM>, the input shaft <NUM> and the output shaft <NUM> linearly extend in the vehicle front-rear direction. The counter shaft <NUM> linearly extends in the vehicle front-rear direction in parallel with the input shaft <NUM> and the output shaft <NUM>. The input shaft <NUM>, the output shaft <NUM>, and the counter shaft <NUM> extend in the horizontal direction or a substantially horizontal direction.

Particularly, as illustrated in <FIG>, the input shaft <NUM>, the output shaft <NUM>, and the counter shaft <NUM> are separately arranged in the vehicle width direction and arranged in positions overlapping with each other in the vehicle up-down direction. A reverse shaft <NUM> linearly extends in the vehicle front-rear direction in parallel with the input shaft <NUM>, the output shaft <NUM>, and the counter shaft <NUM> and extends in the horizontal direction or a substantially horizontal direction below the input shaft <NUM>, the output shaft <NUM>, and the counter shaft <NUM>.

As illustrated in <FIG>, the transmission gear unit <NUM> has, in order from the vehicle front side, the driving gear <NUM> for the fourth speed stage, the driven gear <NUM> for the sixth speed stage, the driven gear <NUM> for the fifth speed stage, the driven gear <NUM> for the second speed stage, the driven gear <NUM> for the third speed stage, and the driven gear <NUM> for the first speed stage as the first gears <NUM> to <NUM> provided to the input shaft <NUM> or the output shaft <NUM> and has, in order from the vehicle front side, the driven gear <NUM> for the fourth speed stage, the driving gear <NUM> for the sixth speed stage, the driving gear <NUM> for the fifth speed stage, the driving gear <NUM> for the second speed stage, the driving gear <NUM> for the third speed stage, and the driving gear <NUM> for the first speed stage as the second gears <NUM> to <NUM> provided to the counter shaft <NUM>.

The first gears <NUM> to <NUM> and the second gears <NUM> to <NUM> constitute plural respective gear trains G1 to G6 of, in order from the vehicle front side, the gear train G4 for the fourth speed stage, the gear train G6 for the sixth speed stage, the gear train G5 for the fifth speed stage, the gear train G2 for the second speed stage, the gear train G3 for the third speed stage, and the gear train G1 for the first speed stage.

Among the gear train G1 for the first speed stage to the gear train G6 for the sixth speed stage, as for the gear train G3 for the third speed stage, its maximum gear diameters are particularly formed to be smallest among the gear diameters (the diameters of gears) of the first gears and second gears as sets of two gears configuring the gear trains, and the dimensions of the first gear and the second gear in the up-down direction are formed smallest.

As illustrated in <FIG>, the drive shaft <NUM> is arranged on an upper side of the transmission gear unit <NUM> and extends in the vehicle width direction on a central side of the transmission mechanism unit <NUM> in the vehicle front-rear direction. The drive shaft <NUM> is particularly arranged in a position, in the vehicle front-rear direction, overlapping with a portion, in the vehicle front-rear direction, in which the plural gear trains G1 to G6 of the transmission gear unit <NUM> are arranged and is particularly arranged on a central side, in the vehicle front-rear direction, of the portion in which the plural gear trains G1 to G6 are arranged. The drive shafts 4a and 4b linearly extend in the vehicle width direction which is orthogonal to the vehicle front-rear direction, and the drive shaft 4b on the vehicle right side extends in the vehicle width direction on a central side of the transmission mechanism unit <NUM> in the vehicle front-rear direction.

The drive shaft <NUM> extends in the vehicle width direction in a position, in the vehicle front-rear direction, corresponding to a predetermined gear train G3 of which the first gear and the second gear have the smallest dimensions in the up-down direction among the plural gear trains G1 to G6 of the transmission gear unit <NUM> and is arranged in a position overlapping with the predetermined gear train G3 in the vehicle front-rear direction. In the present embodiment, the drive shaft <NUM> extends in the vehicle width direction in a position, in the vehicle front-rear direction, corresponding to the gear train G3 for the third speed stage, that is, in a position overlapping with the gear train G3 in the vehicle front-rear direction.

In the present embodiment, although the drive shaft <NUM> is provided while corresponding to the gear train G3 for the third speed stage, in a case where the gear train G4 for the fourth speed stage is arranged on a central side of the transmission mechanism unit <NUM> in the vehicle front-rear direction, the drive shaft <NUM> may be provided in a position, in the vehicle front-rear direction, corresponding to the gear train G4 for the fourth speed stage. The drive shaft <NUM> is provided in a position, in the vehicle front-rear direction, corresponding to the gear trains G3 and G4 for the intermediate speed stages as predetermined gear trains of which the first gears and the second gears have small dimensions in the up-down direction.

In the transmission <NUM>, the gear train G1 for the first speed stage and the gear train for the second speed stage are set as gear trains for the low speed stages, the gear train G5 for the fifth speed stage and the gear train G6 for the sixth speed stage are set as gear trains for the high speed stages, and the gear train G3 for the third speed stage and the gear train G4 for the fourth speed stage are set as gear trains for the intermediate speed stages.

In a case where the gear train for the first speed stage to the gear train for the fifth speed stage are set as gear trains for forward shift stages, the gear train for the first speed stage is set as the gear train for the low speed stage, the gear train for the fifth speed stage is set as a gear train for the high speed stage, the gear train for the second speed stage to the gear train for the fourth speed stage are set as gear trains for the intermediate speed stages, and the drive shaft <NUM> is provided in a position, in the vehicle front-rear direction, corresponding to the gear train for the second speed stage to the gear train for the fourth speed stage, which are the gear trains for the intermediate speed stages, as predetermined gear trains of which the first gears and the second gears have small dimensions in the up-down direction.

In a case where plural gear trains that are at least three or more gear trains are provided as the gear trains for the forward shift stages, the drive shaft <NUM> is provided in a position, in the vehicle front-rear direction, corresponding to the gear train for the intermediate speed stage as the predetermined gear train of which the first gear and the second gear have small dimensions in the up-down direction and is particularly provided in a position, in the vehicle front-rear direction, corresponding to a predetermined gear train of which the first gear and the second gear have the smallest dimensions in the up-down direction.

As illustrated in <FIG>, the transmission gear operation unit <NUM> is arranged on an upper side of the transmission gear unit <NUM>. The transmission gear operation unit <NUM> includes the plural shift rods <NUM>, <NUM>, <NUM>, and <NUM> which respectively support the plural shift forks 61a, 62a, 63a, and 64a and are particularly arranged in parallel with each other, the shift drum <NUM> which has the shift grooves 65a, 65b, 65c, and 65d corresponding to the plural shift rods <NUM>, <NUM>, <NUM>, and <NUM>, and the motor <NUM> as the actuator which causes the shift drum <NUM> to be driven to rotate and causes the plural shift rods <NUM>, <NUM>, <NUM>, and <NUM> to be operated to move.

As for the plural shift rods <NUM>, <NUM>, <NUM>, and <NUM> of the transmission gear operation unit <NUM>, specifically, the four shift rods <NUM>, <NUM>, <NUM>, and <NUM> are arranged to extend in the vehicle front-rear direction above the drive shaft <NUM>. Each of the shift rods <NUM>, <NUM>, <NUM>, and <NUM> is arranged to linearly extend in the vehicle front-rear direction and to extend in the horizontal direction or a substantially horizontal direction above the input shaft <NUM>, the output shaft <NUM>, and the counter shaft <NUM>.

As illustrated in <FIG>, in order from the vehicle left side, the four shift rods <NUM>, <NUM>, <NUM>, and <NUM>, specifically, the first shift rod <NUM>, the second shift rod <NUM>, the third shift rod <NUM>, and the fourth shift rod <NUM> are particularly arranged separately in the vehicle width direction and in positions overlapping with each other in the vehicle up-down direction.

Particularly, the shift forks 61a, 62a, 63a, and 64a respectively supported by the shift rods <NUM>, <NUM>, <NUM>, and <NUM> extend downward from the shift rods <NUM>, <NUM>, <NUM>, and <NUM> and extend in directions orthogonal to the vehicle front-rear direction. The plural shift forks 61a, 62a, 63a, and 64a are separately provided in the vehicle front-rear direction. In order from the vehicle front side, the first shift fork 61a, the fourth shift fork 64a, the second shift fork 62a, and the third shift fork 63a are separately provided in the vehicle front-rear direction. In other words, the fourth shift fork 64a and the second shift fork 62a are located between the first shift fork 61a and the third shift fork 63a in the vehicle front-rear direction.

Particularly, the shift arms 61b, 62b, 63b, and 64b respectively supported by the shift rods <NUM>, <NUM>, <NUM>, and <NUM> extend upward from the shift rods <NUM>, <NUM>, <NUM>, and <NUM>. The plural shift arms 61b, 62b, 63b, and 64b are separately provided in the vehicle front-rear direction, and the projection portions 61c, 62c, 63c, and 64c in the distal end portions of the shift arms 61b, 62b, 63b, and 64b are respectively engaged with the shift grooves 65a, 65b, 65c, and 65d of the shift drum <NUM>.

As illustrated in <FIG>, the shift drum <NUM> and the motor <NUM> are particularly arranged above the plural shift rods <NUM>, <NUM>, <NUM>, and <NUM> on a vehicle rear side of the transmission mechanism unit <NUM>. Each of the shift drum <NUM> and the motor <NUM> is arranged such that its axis line extends in the vehicle front-rear direction. The motor <NUM> is arranged above the shift drum <NUM>.

As illustrated in <FIG>, the drive shaft <NUM> particularly extends in the vehicle width direction in a position, in the vehicle up-down direction, overlapping with the transmission mechanism unit <NUM> on a central side of the transmission mechanism unit <NUM> in the vehicle up-down direction. The drive shaft <NUM> particularly extends in the vehicle width direction through a portion between the transmission gear unit <NUM> and the transmission gear operation unit <NUM> arranged on the upper side of the transmission gear unit <NUM>, specifically, a portion between the transmission gear unit <NUM> and the plural shift rods <NUM>, <NUM>, <NUM>, and <NUM> of the transmission gear operation unit <NUM>. The drive shaft <NUM> can be arranged with high assemblability between the transmission gear unit <NUM> and the transmission gear operation unit <NUM> which are dispersedly arranged in the vehicle up-down direction.

As illustrated in <FIG>, the drive shaft <NUM> particularly extends in the vehicle width direction through a portion among the plural shift forks 61a, 62a, 63a, and 64a. In the transmission <NUM>, the drive shaft <NUM> extends in the vehicle width direction through a portion between the fourth shift fork 64a and the second shift fork 62a which are separately arranged in the vehicle front-rear direction.

In the vehicle <NUM>, the transmission <NUM> is particularly arranged in the vicinity of the drive shaft <NUM> in the vehicle-body rear portion, and the drive shaft <NUM> particularly extends in the vehicle width direction on a central side in the vehicle front-rear direction and on a central side in the vehicle up-down direction of the transmission mechanism unit <NUM> of the transmission <NUM> and extends in the vehicle width direction such that the drive shaft <NUM> passes through the transmission casing <NUM>. As for the drive shaft 4b on the vehicle right side, a portion of the drive shaft 4b particularly passes through the side face portion 11b on the vehicle right side of the transmission casing <NUM>, and a portion of the drive shaft 4b, which is positioned on the vehicle left side of the above portion of the drive shaft 4b, passes through the side face portion 11b on the vehicle left side of the transmission casing <NUM>.

The drive shaft <NUM> particularly extends in the vehicle width direction through a portion between the transmission gear unit <NUM> and the transmission gear operation unit <NUM> of the transmission mechanism unit <NUM> and extends in the vehicle width direction in a position, in the vehicle front-rear direction, corresponding to the predetermined gear train G3 of which the first gear and the second gear have small dimensions in the up-down direction among the plural gear trains G1 to G6 configuring the transmission gear unit <NUM>.

In the present embodiment, the input shaft <NUM>, the output shaft <NUM>, and the counter shaft <NUM> are capable of being arranged while being offset in the vehicle up-down direction but are particularly arranged in positions overlapping with each other in the vehicle up-down direction. The differential device <NUM> is arranged on the vehicle left side of the transmission <NUM> but is also capable of being arranged on the vehicle right side of the transmission <NUM>.

Further, as the actuator causing the plural shift rods <NUM>, <NUM>, <NUM>, and <NUM> to be operated to move, the motor <NUM> is used, and an electric actuator is used; however, an actuator such as a hydraulic actuator may be used to cause the plural shift rods <NUM>, <NUM>, <NUM>, and <NUM> to be operated to move. In the present embodiment, the transmission <NUM> is used which causes the shift rods <NUM>, <NUM>, <NUM>, and <NUM> to be operated to move by the actuator on the basis of a manual transmission, but the transmission <NUM> is similarly applicable to a manual transmission.

As described above, the motive power transmission device <NUM> for a vehicle according to the present embodiment includes the transmission <NUM> that outputs motive power input from a drive source <NUM> while performing gear-shifting for the motive power and the drive shaft <NUM> that is coupled with the transmission <NUM> and transmits the motive power from the drive source <NUM>, which is output from the transmission <NUM>, to the drive wheels <NUM>. The transmission <NUM> has the transmission mechanism unit <NUM> that is arranged in the transmission casing <NUM> such that the axis line extends in the vehicle front-rear direction and that performs gear-shifting for the motive power from the drive source <NUM>. The drive shaft <NUM> extends in the vehicle width direction on a central side of the transmission mechanism unit <NUM> in the vehicle front-rear direction and is provided such that the drive shaft <NUM> passes through the transmission casing <NUM>.

Accordingly, in a case where the transmission <NUM> is arranged in the vicinity of the drive shaft <NUM> in the vehicle-body rear portion in the vehicle <NUM> including the longitudinal placement type transmission <NUM>, because the drive shaft <NUM> extends in the vehicle width direction on a central side of the transmission mechanism unit <NUM> in the vehicle front-rear direction such that the drive shaft <NUM> passes through the transmission casing <NUM>, lowering of comfortability of an occupant due to narrowing of a vehicle cabin space by the transmission can be inhibited compared to a case where the transmission is arranged on the vehicle front side of the drive shaft. Further, lowering of operation stability due to enlargement of an overhang on the vehicle rear side can be inhibited compared to a case where the transmission is arranged on the vehicle rear side of the drive shaft.

Consequently, in a case where the transmission <NUM> is arranged in the vicinity of the drive shaft <NUM> in the vehicle-body rear portion in the vehicle <NUM> including the longitudinal placement type transmission <NUM>, both of comfortability of an occupant and operation stability can be achieved.

Further, the drive shaft <NUM> extends in the vehicle width direction on a central side of the transmission mechanism unit <NUM> in the vehicle up-down direction. Accordingly, the position of the center of gravity of the vehicle <NUM> is lowered compared to a case where the transmission is arranged above the drive shaft <NUM>, and operation stability can thereby be improved. Further, compared to a case where the transmission is arranged below the drive shaft, a gap from a ground surface is increased, and a ground clearance can thereby be secured.

Further, the transmission mechanism unit <NUM> includes the input shaft <NUM> and the output shaft <NUM> that are arranged on the same axis line, the counter shaft <NUM> that is arranged in parallel with the input shaft <NUM> and the output shaft <NUM>, and the transmission gear unit <NUM> that has the plural gear trains G1 to G6 which are respectively formed with the first gears <NUM> to <NUM> provided to the input shaft <NUM> or the output shaft <NUM> and the second gears <NUM> to <NUM> provided to the counter shaft <NUM> and meshing with the first gears <NUM> to <NUM>, and the drive shaft <NUM> extends in the vehicle width direction in a position, in the vehicle front-rear direction, corresponding to the predetermined gear train G3 of which the first gear and the second gear have small dimensions in the up-down direction among the plural gear trains G1 to G6.

Accordingly, the drive shaft <NUM> is arranged close to the axis line of the transmission mechanism unit <NUM>, and the transmission <NUM> and the drive shaft <NUM> can thereby compactly be arranged in the vehicle up-down direction.

Further, the transmission mechanism unit <NUM> includes the input shaft <NUM> and the output shaft <NUM> that are arranged on the same axis line, the counter shaft <NUM> that is arranged in parallel with the input shaft <NUM> and the output shaft <NUM>, the transmission gear unit <NUM> that has the plural gear trains G1 to G6 which are respectively formed with the first gears <NUM> to <NUM> provided to the input shaft <NUM> or the output shaft <NUM> and the second gears <NUM> to <NUM> provided to the counter shaft <NUM> and meshing with the first gears <NUM> to <NUM>, and the transmission gear operation unit <NUM> that operates the transmission gear unit <NUM>, and the drive shaft <NUM> extends in the vehicle width direction through a portion between the transmission gear unit <NUM> and the transmission gear operation unit <NUM>.

Accordingly, compared to a case where the drive shaft extends in the vehicle width direction through a portion in the transmission gear unit and a portion in the transmission gear operation unit, the drive shaft <NUM> can be arranged with high assemblability between the transmission gear unit <NUM> and the transmission gear operation unit <NUM> that are dispersedly arranged in the vehicle up-down direction, and the drive shaft <NUM> and the transmission <NUM> can thereby be arranged with high assemblability.

Further, the motive power transmission device <NUM> for a vehicle includes the differential device <NUM> that is coupled with the transmission <NUM> and coupled with the drive shaft <NUM> and transmits the motive power from the drive source <NUM>, which is output from the transmission <NUM>, to the drive shaft <NUM>.

Accordingly, in the vehicle <NUM> including the differential device <NUM> that is coupled with the longitudinal placement type transmission <NUM> and coupled with the drive shaft <NUM>, the drive shaft <NUM> extends in the vehicle width direction on a central side of the transmission mechanism unit <NUM> in the vehicle front-rear direction such that the drive shaft <NUM> passes through the transmission casing <NUM>, and both of comfortability of an occupant and operation stability can thereby be achieved.

Further, the motive power transmission device <NUM> for a vehicle includes the differential housing <NUM> in which the differential device <NUM> is housed, and the differential housing <NUM> is integrally formed with the transmission casing <NUM>. Accordingly, compared to a case where the differential housing is arranged in the vehicle width direction without being integrally formed with the transmission casing <NUM>, the differential housing <NUM> and the transmission casing <NUM> can compactly be formed.

The present invention is not limited to the embodiment described as an example.

Claim 1:
A motive power transmission device (<NUM>) for a vehicle (<NUM>), comprising:
a transmission (<NUM>) configured to perform gear-shifting and to output motive power input from a drive source (<NUM>); and
a drive shaft (<NUM>) that is coupled with the transmission (<NUM>) and configured to transmit the motive power from the drive source (<NUM>), which is output from the transmission (<NUM>), to a drive wheel (<NUM>), wherein
the transmission (<NUM>) has a transmission mechanism unit (<NUM>) that is arranged in a transmission casing (<NUM>) such that an axis line extends in a vehicle front-rear direction and that performs gear-shifting for the motive power from the drive source (<NUM>),
the drive shaft (<NUM>) extends in a vehicle width direction on a central side of the transmission mechanism unit (<NUM>) in the vehicle front-rear direction and is provided such that the drive shaft (<NUM>) passes through the transmission casing (<NUM>), and
the transmission mechanism unit (<NUM>) includes
an input shaft (<NUM>) and an output shaft (<NUM>) that are arranged on the same axis line,
a counter shaft (<NUM>) that is arranged in parallel with the input shaft (<NUM>) and the output shaft (<NUM>), and
a transmission gear unit (<NUM>) that has plural gear trains (G1 to G6) each of which is formed with a first gear (<NUM> to <NUM>) provided to the input shaft (<NUM>) or the output shaft (<NUM>) and a second gear (<NUM> to <NUM>) provided to the counter shaft (<NUM>) and meshing with the first gear (<NUM> to <NUM>),
characterized in that
the transmission mechanism unit (<NUM>) further includes a transmission gear operation unit (<NUM>) configured to operate the transmission gear unit (<NUM>),
the drive shaft (<NUM>) extends in the vehicle width direction through a portion between the transmission gear unit (<NUM>) and the transmission gear operation unit (<NUM>),
the drive shaft (<NUM>) extends in the vehicle width direction through a portion between the transmission gear unit (<NUM>) and plural shift rods (<NUM>, <NUM>, <NUM>, <NUM>) of the transmission gear operation unit (<NUM>), and
the plural shift rods (<NUM>, <NUM>, <NUM>, <NUM>) are arranged to extend in the vehicle front-rear direction above the drive shaft (<NUM>).