All-wheel drive vehicle

Abstract

In a configuration where the engine is mounted transversely near the rear drive shaft, the present invention provides an all-wheel-drive vehicle that makes it easier to secure passenger space in front of the engine in the forward and backward directions. [Solution] The transversely mounted engine is located near the rear drive shaft. The transmission, which transmits power from the engine, is located coaxially with the engine output shaft. The rear differential gear distributes power from the engine, transmitted via the transmission, to the rear drive shaft. The transfer case distributes power from the engine, transmitted via the transmission, to the front wheels. The propeller shaft transmits power from the engine, transmitted via the transfer case, to the front drive shaft. The front differential gear distributes power from the engine, transmitted via the propeller shaft, to the front drive shaft. The transfer case is located behind the engine in the forward and backward direction.

Description

Technical Field

[0001] The present invention relates to an all-wheel drive vehicle with an engine disposed at the rear.

Background Art

[0002] An all-wheel drive vehicle including left and right front wheels, left and right front drive shafts for driving each of the front wheels, left and right rear wheels, left and right rear drive shafts for driving each of the rear wheels, a horizontally disposed engine disposed in the vicinity of the rear drive shafts and having an axis of an engine output shaft in the vehicle width direction, a transmission disposed coaxially with the engine output shaft for transmitting power from the engine, a rear differential gear disposed coaxially with the rear drive shafts for distributing the power from the engine transmitted through the transmission to each of the rear drive shafts, a transfer for distributing the power from the engine transmitted through the transmission to the front wheels, a propeller shaft for transmitting the power from the engine transmitted through the transfer to the front drive shafts, and a front differential gear disposed coaxially with the front drive shafts for distributing the power from the engine transmitted through the propeller shaft to each of the front drive shafts is well known. For example, a midship 4-wheel drive horizontally disposed transmission described in Patent Document 1 is such a vehicle. Patent Document 1 discloses providing a rear differential gear rearward from a main shaft of the transmission and a transfer forward, taking out an output shaft of the transfer forward, and connecting it to a front differential gear with a propeller shaft.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

[0004] By the way, in the all-wheel drive vehicle described in Patent Document 1, the transfer case is positioned in front of the transmission in the forward and reverse directions, that is, in front of the engine. Therefore, in a mid-engine layout where the passenger compartment is already small, it becomes difficult to secure passenger space in front of the engine in the forward and reverse directions.

[0005] The present invention was made against the above circumstances, and its objective is to provide an all-wheel drive vehicle in which a transversely mounted engine is positioned near the rear drive shaft, making it easier to secure passenger space in front of the engine in the forward and backward directions. [Means for solving the problem]

[0006] The gist of the first invention is (a) left and right front wheels, left and right front drive shafts that drive each of the front wheels, left and right rear wheels, left and right rear drive shafts that drive each of the rear wheels, a transversely mounted engine located near the rear drive shafts, the axis of the engine output shaft being in the direction of the vehicle width, a transmission that transmits power from the engine and is located coaxially with the engine output shaft, and a rear differential that distributes the power from the engine transmitted via the transmission to each of the rear drive shafts, located coaxially with the rear drive shafts. An all-wheel-drive vehicle comprising: gears; a transfer case for distributing power from the engine transmitted via the transmission to the front wheels; a propeller shaft for transmitting power from the engine transmitted via the transfer case to the front drive shafts; and a front differential gear, which is arranged coaxially with the front drive shafts and distributes power from the engine transmitted via the propeller shaft to each of the front drive shafts, wherein (b) the transfer case is positioned rearward in the forward and reverse direction relative to the engine. [Effects of the Invention]

[0007] According to the first invention, a transversely mounted engine, whose engine output shaft axis is in the vehicle width direction, is positioned near the rear drive shafts. The transmission that transmits power from the engine is positioned coaxially with the engine output shaft. The rear differential gear distributes the power from the engine transmitted via the transmission to each of the rear drive shafts. The transfer case distributes the power from the engine transmitted via the transmission to the front wheels. The propeller shaft transmits the power from the engine transmitted via the transfer case to the front drive shafts. The front differential gear distributes the power from the engine transmitted via the propeller shaft to each of the front drive shafts. The transfer case is positioned behind the engine in the forward and backward direction. Therefore, in an all-wheel-drive vehicle with a transversely mounted engine positioned near the rear drive shafts, it is easier to secure passenger space in front of the engine in the forward and backward direction. [Brief explanation of the drawing]

[0008] [Figure 1] This diagram illustrates the schematic configuration of a vehicle to which the present invention is applied. [Figure 2] This is a partial cross-sectional view of the input-side components of the transfer case and their vicinity, taken from above in the vertical direction while the device is mounted in a vehicle. [Figure 3] This is a partial cross-sectional view of the output side component of the transfer case and its vicinity, viewed from the left side in the vehicle width direction. [Figure 4] This diagram shows the output component of the transfer case and its vicinity, viewed from the rear in the forward and backward direction. [Modes for carrying out the invention]

[0009] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. [Examples]

[0010] Figure 1 is a diagram illustrating the schematic configuration of an all-wheel drive vehicle 10 to which the present invention is applied. In Figure 1, the all-wheel drive vehicle 10 comprises left and right front wheels 12, left and right rear wheels 14, left and right front drive shafts 16 that drive each of the front wheels 12, and left and right rear drive shafts 18 that drive each of the rear wheels 14. The all-wheel drive vehicle 10 also comprises a front differential gear 20 and a rear differential gear 22. The all-wheel drive vehicle 10 also comprises an engine 24, a transmission 26, a transfer case 28, a propeller shaft 30, and a coupling 32.

[0011] The front wheels 12 include the left front wheel 12L and the right front wheel 12R. The rear wheels 14 include the left rear wheel 14L and the right rear wheel 14R. The front drive shaft 16 includes the left front drive shaft 16L, which connects the front differential gear 20 to the left front wheel 12L, and the right front drive shaft 16R, which connects the front differential gear 20 to the right front wheel 12R. The rear drive shaft 18 includes the left rear drive shaft 18L, which connects the rear differential gear 22 to the left rear wheel 14L, and the right rear drive shaft 18R, which connects the rear differential gear 22 to the right rear wheel 14R. Note that the above "left and right" refers to left and right with respect to the forward direction of the all-wheel drive vehicle 10.

[0012] Engine 24 is, for example, a known internal combustion engine. Engine 24 is a transversely mounted engine in which the axis CL1 of the engine output shaft 24a is in the vehicle width direction (synonymous with the horizontal direction). Engine 24 is located on the rear wheel 14 side. In other words, engine 24 is located in the vicinity of the rear drive shaft 18. For example, engine 24 is located forward of the rear drive shaft 18 in the forward / reverse direction (synonymous with the vehicle's longitudinal direction). In other words, engine 24 is in a so-called mid-ship layout.

[0013] The transmission 26 is located adjacent to the engine 24, coaxially with the engine output shaft 24a. The transmission 26 constitutes a common part of the power transmission path between the engine 24 and the front wheel 12, and between the engine 24 and the rear wheel 14. The transmission 26 transmits power from the engine 24 to the subsequent stages, i.e., to the front wheel 12 (also known as the front drive shaft 16) and the rear wheel 14 (also known as the rear drive shaft 18). The transmission 26 is, for example, a known planetary gear type multi-stage transmission in which multiple gears with different gear ratios can be selectively set, a known continuously variable transmission in which the gear ratio can be changed continuously without stepless changes, or a known synchronous mesh type parallel shaft transmission. In Figure 1, a synchronous mesh type parallel shaft manual transmission is shown as an example of the transmission 26.

[0014] The rear differential gear 22 is positioned on the axis CL2 of the rear drive shaft 18, that is, coaxially with the rear drive shaft 18. The rear differential gear 22 is connected to the transmission 26. The rear differential gear 22 is a rear differential gear mechanism that distributes power from the engine 24 transmitted via the transmission 26 to each of the rear drive shafts 18, that is, to each of the rear wheels 14, and also allows for differential rotation between the left and right rear wheels 14.

[0015] The transfer case 28 is connected to the transmission 26. The transfer case 28 is a front-to-rear wheel power distribution device that distributes power from the engine 24, transmitted via the transmission 26, to the front wheels 12.

[0016] The propeller shaft 30 is connected to the transfer case 28. The propeller shaft 30 transmits power from the engine 24, which is transmitted via the transfer case 28, from the rear wheels 14 to the front wheels 12. In other words, the propeller shaft 30 transmits power from the engine 24, which is transmitted via the transfer case 28, to the front wheels 12 (the front drive shaft 16 is also equivalent).

[0017] The front differential gear 20 is arranged on the axis CL3 of the front drive shaft 16, that is, coaxially with the front drive shaft 16. The front differential gear 20 is connected to the propeller shaft 30 via a coupling 32. The front differential gear 20 is a differential gear mechanism for the front wheels that distributes the power from the engine 24 transmitted via the propeller shaft 30 to each of the front drive shafts 16, that is, to each of the front wheels 12, and allows differential rotation between the left and right of the front wheels 12.

[0018] The coupling 32 is provided in the power transmission path between the propeller shaft 30 and the front differential gear 20. The coupling 32 is a known electronically controlled coupling composed of, for example, a wet multi-plate clutch, in which the transmission torque is controlled by an electrical signal from an electronic control device (not shown) provided in the all-wheel drive vehicle 10. By controlling the transmission torque, the coupling 32 can continuously change the torque distribution between the front and rear wheels, for example, between 0:100 and 50:50.

[0019] In the power transmission path between the engine 24 and the rear wheels 14, the power from the engine 24 is transmitted to the rear wheels 14 through the transmission 26, the rear differential gear 22, the rear drive shaft 18, etc. in sequence. In the power transmission path between the engine 24 and the front wheels 12, the power from the engine 24 is transmitted to the front wheels 12 through the transmission 26, the transfer 28, the propeller shaft 30, the coupling 32, the front differential gear 20, the front drive shaft 16, etc. in sequence.

[0020] The all-wheel drive vehicle 10 is a vehicle capable of adjusting the drive torque distribution between the front wheels 12 and the rear wheels 14. The all-wheel drive vehicle 10 has two front wheels 12 and two rear wheels 14 respectively, and since it is a vehicle equipped with four wheels, it is also a four-wheel drive vehicle. In this embodiment, all-wheel drive (AWD) and four-wheel drive (4WD) are synonymous. In addition to traveling in the AWD control (the AWD state is also synonymous) that drives the front wheels 12 and the rear wheels 14, the all-wheel drive vehicle 10 can also travel in the rear-wheel drive (RWD) control (the RWD state is also synonymous) that drives only the rear wheels 14 and the two-wheel drive (=2WD) control (the 2WD state is also synonymous).

[0021] By the way, in the all-wheel drive vehicle 10, it is conceivable to arrange the transfer 28 in front of the engine 24 in the longitudinal direction. Then, in the all-wheel drive vehicle 10 originally configured with a midship layout with a small living space, it becomes difficult to secure the living space in front of the engine 24. Also, it is necessary to separate the power transmission from the engine 24 via the transmission 26 to the rear differential gear 22 and the transfer 28, and the transfer 28 cannot be directly connected to the rear differential case 22c which is the input rotating member of the rear differential gear 22. Therefore, additional members such as gears and shafts are required, which may lead to an increase in cost and mass.

[0022] Therefore, in the all-wheel drive vehicle 10, the transfer 28 is arranged behind the engine 24 in the longitudinal direction. Also, the transfer 28 is directly connected to the rear differential case 22c and is connected to the transmission 26 via the rear differential case 22c.

[0023] Figure 2 is a partial cross-sectional view of the members on the input side of the transfer 28 and its vicinity as viewed from above in the vertical direction in the vehicle-mounted state, that is, the state of being mounted on the all-wheel drive vehicle 10. Figure 3 is a partial cross-sectional view of the members on the output side of the transfer 28 and its vicinity as viewed from the left side in the vehicle width direction. Figure 4 is a view of the members on the output side of the transfer 28 and its vicinity as viewed from the rear in the longitudinal direction.

[0024] In Figures 1-4, the transfer 28 comprises a transfer input member 50 and a transfer output member 60 connected to the transfer input member 50.

[0025] The transfer input member 50 comprises a transfer input shaft 52 and a transfer input gear 54 fixed to one end of the transfer input shaft 52. The transfer input shaft 52 is a rotating shaft whose other end is connected to the transmission 26 via an input rotating member of the rear differential gear 22. For example, the transfer input shaft 52 is connected to the transmission 26 by its other end being connected to the rear differential case 22c. The rear differential case 22c is connected to the transmission 26 via a rear differential ring gear 22r which is integrally connected to the rear differential case 22c. The rear differential ring gear 22r functions as an input rotating member of the rear differential gear 22, similar to the rear differential case 22c. The transfer input shaft 52 is positioned on the axis CL2 of the rear drive shaft 18, alongside the rear differential gear 22. Furthermore, depending on the position of the rear differential ring gear 22r, the transfer input shaft 52 may also be connected to the transmission 26 by having its other end connected to the rear differential ring gear 22r. Also, "fixed" is synonymous with "fixed so that relative rotation is impossible."

[0026] The transfer output member 60 comprises a first transfer output shaft 62, a transfer output gear 64 fixed to one end of the first transfer output shaft 62, a second transfer output shaft 66 arranged parallel to the first transfer output shaft 62, and a connecting member 70. The first transfer output shaft 62 is a rotating shaft extending from one end to the other in the rearward direction in the forward and backward direction. The transfer output gear 64 is a gear that meshes with the transfer input gear 54. For example, the transfer output gear 64 is a hypoid pinion that, together with the transfer input gear 54, constitutes a hypoid gear. The second transfer output shaft 66 is a rotating shaft with one end connected to the propeller shaft 30. The connecting member 70 is a member that connects the other end of the first transfer output shaft 62 to the other end of the second transfer output shaft 66.

[0027] The connecting member 70 comprises a first gear 72, a second gear 74, and a transmission member 76. The first gear 72 is a gear fixed to the other end of the first transfer output shaft 62. The second gear 74 is a gear fixed to the other end of the second transfer output shaft 66. The transmission member 76 is a member wrapped around the first gear 72 and the second gear 74. For example, the transmission member 76 is a chain or a belt. In particular, the transmission member 76 is a silent chain.

[0028] In the transfer output member 60, the second transfer output shaft 66 is positioned below or near below the first transfer output shaft 62 in the vertical direction when mounted on the vehicle. As a result, the second transfer output shaft 66 passes below the engine 24 in the vertical direction when mounted on the vehicle and is connected to the propeller shaft 30.

[0029] As described above, in this embodiment, the transversely mounted engine 24, whose engine output shaft 24a's axis CL1 is in the vehicle width direction, is positioned near the rear drive shaft 18. The transmission 26, which transmits power from the engine 24, is positioned coaxially with the engine output shaft 24a. The rear differential gear 22 distributes the power from the engine 24 transmitted via the transmission 26 to each of the rear drive shafts 18. The transfer case 28 distributes the power from the engine 24 transmitted via the transmission 26 to the front wheels 12. The propeller shaft 30 transmits the power from the engine 24 transmitted via the transfer case 28 to the front drive shafts 16. The front differential gear 20 distributes the power from the engine 24 transmitted via the propeller shaft 30 to each of the front drive shafts 16. The transfer case 28 is positioned rearward in the forward / reverse direction relative to the engine 24. Therefore, in an all-wheel-drive vehicle 10 configured to have a transversely mounted engine 24 positioned near the rear drive shaft 18, it is easier to secure passenger space in front of the engine 24 in the forward and backward directions.

[0030] Furthermore, according to this embodiment, the transfer case 28 includes a transfer input member 50 equipped with a transfer input shaft 52 and a transfer input gear 54, and a transfer output member 60 connected to the transfer input member 50. The other end of the transfer input shaft 52 is connected to the transmission 26 via the input rotating member (rear differential case 22c, rear differential ring gear 22r) of the rear differential gear 22, and is arranged coaxially with the rear drive shaft 18 and alongside the rear differential gear 22. This allows the transfer case 28 to be directly connected to the rear differential case 22c, eliminating the need for additional components such as gears and shafts, thereby suppressing increases in cost and mass.

[0031] Furthermore, according to this embodiment, the transfer output member 60 includes a first transfer output shaft 62, a transfer output gear 64, a second transfer output shaft 66, and a connecting member 70 that connects the first transfer output shaft 62 and the second transfer output shaft 66. This allows the transfer 28 to appropriately distribute power from the engine 24 transmitted via the transmission 26 to the front wheels 12 in a configuration where the transfer 28 is positioned rearward in the forward / reverse direction relative to the engine 24.

[0032] Furthermore, according to this embodiment, the connecting member 70 includes a first gear 72, a second gear 74, and a transmission member 76. This makes it easy to scoop up lubricating oil, etc., accumulated in the lower part of the case housing the connecting member 70 in the vertical direction when mounted on a vehicle, from below to above.

[0033] Furthermore, according to this embodiment, the engine 24 is positioned forward in the forward direction relative to the rear drive shaft 18. This makes it easier to secure passenger space in front of the engine 24 in the forward direction in an all-wheel-drive vehicle 10 with a mid-ship layout.

[0034] Although embodiments of the present invention have been described in detail above with reference to the drawings, the present invention is also applicable to other embodiments.

[0035] For example, in the above embodiment, the connecting member 70 may be configured to include a gear fixed to the other end of the first transfer output shaft 62 and a gear fixed to the other end of the second transfer output shaft 66, with these gears meshing together. However, in a configuration where the gears mesh together, if the rotational directions of the first transfer output shaft 62 and the second transfer output shaft 66 are to be aligned, it is necessary to mesh the gears together via, for example, a counter gear. In other words, in a configuration where the gears mesh together, a three-axis configuration may be required, consisting of the first transfer output shaft 62, the second transfer output shaft 66, and a counter shaft to which the counter gear is fixed. In this case, there is a risk of increased cost and mass. Furthermore, in a configuration where the gears mesh together, a helical gear is required to deal with noise and vibration. In that case, an axial load is applied to the bearing that holds the helical gear. Therefore, bearings and settings to handle axial loads become necessary, which may increase the number of parts and complicate assembly. In contrast, when the connecting member 70 uses a first gear 72, a second gear 74, and a transmission member 76, it is possible to suppress increases in cost, mass, and the number of parts, as well as complicate assembly, compared to a configuration where gears mesh with each other. It is useful to configure the connecting member 70 with the first gear 72, the second gear 74, and the transmission member 76.

[0036] Furthermore, in the above-described embodiment, the coupling 32 may be provided, for example, in the power transmission path between the front differential gear 20 and the front drive shaft 16. Alternatively, the coupling 32 may be replaced with, for example, a clutch that connects or disconnects the power transmission path, or a center differential device that allows differential rotation between the front wheels 12 and the rear wheels 14. In other words, the coupling 32 may be replaced with a mechanism other than the coupling 32 that, when combined with the transfer case 28, enables driving in AWD mode.

[0037] It should be noted that the above-described embodiment is merely one example, and the present invention can be implemented in various modified and improved forms based on the knowledge of those skilled in the art. [Explanation of Symbols]

[0038] 10: All-wheel drive vehicle 12: Front wheel 12L: Left front wheel 12R: Right front wheel 14: Rear wheel 14L: Left rear wheel 14R: Right rear wheel 16: Front drive shaft 16L: Left front drive shaft 16R: Right front drive shaft 18: Rear drive shaft 18L: Left rear drive shaft 18R: Right rear drive shaft 20: Front differential gear 22: Rear differential gear 22c: Rear differential case (input rotating member of rear differential gear) 22r: Rear differential ring gear (input rotating member of rear differential gear) 24: Engine 24a: Engine output shaft 26: Transmission 28: Transfer case 30: Propeller shaft 50: Transfer input member 52: Transfer input shaft 54: Transfer input gear 60: Transfer output member 62: First transfer output shaft 64: Transfer output gear 66: Second transfer output shaft 70: Connecting member 72: First gear 74: Second gear 76: Transmission member

Claims

1. An all-wheel-drive vehicle comprising: left and right front wheels, left and right front drive shafts driving each of the front wheels, left and right rear wheels, left and right rear drive shafts driving each of the rear wheels, a transversely mounted engine located near the rear drive shafts with the axis of the engine output shaft oriented in the vehicle width direction, a transmission located coaxially with the engine output shaft for transmitting power from the engine, a rear differential gear located coaxially with the rear drive shafts for distributing power from the engine transmitted via the transmission to each of the rear drive shafts, a transfer case for distributing power from the engine transmitted via the transmission to the front wheels, a propeller shaft for transmitting power from the engine transmitted via the transfer case to the front drive shafts, and a front differential gear located coaxially with the front drive shafts for distributing power from the engine transmitted via the propeller shaft to each of the front drive shafts, The transfer case is positioned rearward in the forward / reverse direction relative to the engine, characterized in that it is an all-wheel drive vehicle.

2. The transfer includes a transfer input shaft, a transfer input member having a transfer input gear fixed to one end of the transfer input shaft, and a transfer output member connected to the transfer input member. The all-wheel drive vehicle according to claim 1, characterized in that the other end of the transfer input shaft is connected to the transmission via the input rotating member of the rear differential gear, and is arranged coaxially with the rear drive shaft and alongside the rear differential gear.

3. The all-wheel drive vehicle according to claim 2, characterized in that the transfer output member includes a first transfer output shaft extending from one end to the other end toward the rear in the forward and backward direction, a transfer output gear fixed to one end of the first transfer output shaft and meshing with the transfer input gear, a second transfer output shaft arranged parallel to the first transfer output shaft and having one end connected to the propeller shaft, and a connecting member connecting the other end of the first transfer output shaft and the other end of the second transfer output shaft.

4. The all-wheel drive vehicle according to claim 3, characterized in that the connecting member includes a first gear fixed to the other end of the first transfer output shaft, a second gear fixed to the other end of the second transfer output shaft, and a transmission member wrapped around the first gear and the second gear.

5. The all-wheel drive vehicle according to any one of claims 1 to 4, characterized in that the engine is positioned forward in the forward / reverse direction with respect to the rear drive shaft.

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