JPH10100701A - Power transmission device for four-wheel drive car - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent ill effects upon various gear groups in a center differential device and an inter-wheel differential device as much as possible by heightening the supporting rigidity of a casing member without impairing the effect of constructing in a small size. SOLUTION: A power transmission device of a four-wheel drive car has an outer casing 4 which is fitted internally with an output shaft 7, a center differential device 25 and inter-wheel differential 26 installed in line on the car axles 8 arranged parallel and a cylindrical casing member 35 whose one end is formed as a major diametric cylinder and the other end is formed as a minor diametric cylinder 35a to be fitted on one of the axles 8, wherein the major diametric cylinder is equipped at the periphery with a final ring gear 37 to mesh at a specified reduction ratio with the output gear 36 installed on the output shaft 7. A transfer gear 38 is installed parallel, which is coupled with the casing member 35 and center differential 25 to transmit the driving force to the other axle and is supported rotatably on the outer casing 4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power transmission device for a four-wheel drive vehicle for driving front and rear wheels simultaneously.

[0002]

2. Description of the Related Art Among four-wheel drive vehicles, there is a laterally mounted engine type in which an engine is arranged such that a crank shaft thereof extends in the left-right direction of the vehicle body. In this type of four-wheel drive vehicle, a transfer is added to the transmission, whereby the driving force of the engine is transmitted to the front wheels and the rear wheels. In such a four-wheel drive vehicle, four wheels, that is, front, rear, left, and right, are simultaneously driven at all times, or as necessary. In a vehicle that always drives four wheels, a center differential (differ between wheels) is generally used. However, since the number of components inevitably increases, it is desirable to reduce the axial and radial dimensions of the drive system (ie, the transmission and the transfer) as small as possible to achieve compactness.
Conventionally, various devices have been devised.

As one of them, for example, a transmission and a transfer are arranged in parallel in an outer casing having a predetermined shape, and a final ring gear meshing with a drive gear (ie, an output gear) of an output shaft in the transmission is provided. The casing member is constituted by a cylindrical body having a small-diameter cylindrical body portion and a large-diameter cylindrical body portion, and the small-diameter cylindrical body portion of the casing member is rotatably supported with respect to a differential case via a needle bearing, while the casing member The final ring gear is provided on the outer periphery of the large-diameter cylindrical body, and the center differential and the inter-wheel differential (front and rear) are arranged side by side in close proximity to reduce the axial and radial dimensions. In addition, there has been proposed a device in which the assemblability of a differential device or the like is improved (for example, , See JP-A-63-68425).

[0004]

However, in the above-mentioned known example, the small-diameter cylindrical body of the casing member is rotatably supported on the differential case via a needle bearing so as to rotate about one axle. Since only the transmission is possible, the final ring gear on the outer periphery of the large-diameter cylindrical body of the casing member is greatly reduced and amplified by the engagement with the drive gear on the transmission side (that is, the output gear). When a torque is input, a force in a centripetal direction acts. Then
A phenomenon in which the casing member large-diameter cylindrical body portion without the support portion bends or falls down occurs.

When the above-mentioned phenomenon occurs, a gear group (for example, a planetary gear group) constituting a center differential and a wheel-to-wheel differential disposed in the casing member is adversely affected. Problems such as seizure, abrasion, and abnormal noise may occur due to abnormal meshing.

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and by increasing the support rigidity of a casing member without impairing compactness, it is possible to adversely affect various gear groups in a center differential and a differential between wheels. The purpose is to prevent it.

[0007]

In the configuration of the invention according to claim 1 of the present application, as means for solving the above-mentioned problems,
A transmission having an output shaft extending in the vehicle width direction, which is arranged in series with the horizontal engine, and a center differential and an inter-wheel differential arranged side by side on the axle arranged in parallel with the output shaft are arranged inside, and one end side is provided. A large-diameter cylindrical body, the other end of which is a small-diameter cylindrical body externally fitted to the axle, and a predetermined reduction ratio applied to an output gear provided on the output shaft on the outer periphery of the large-diameter cylindrical body. In a power transmission device for a four-wheel drive vehicle, wherein a cylindrical casing member provided with a final ring gear meshing with the other is disposed in an outer casing, the casing member and the other axle are linked to the center differential. And a transfer gear for transmitting a driving force, and the transfer gear is rotatably supported with respect to the outer casing.

With the above-described structure, the large-diameter cylindrical portion of the casing member is formed by the torque generated when the output power on the transmission side is greatly reduced and the amplified driving force is transmitted to the final ring gear. The transfer gear linked to the center differential located inside the casing member is rotatably supported by the outer casing even if a falling force is applied to the casing member. Falling to the ring gear side can be reliably prevented.

According to a second aspect of the present invention, in the configuration of the first aspect of the present invention, the outer casing is positioned radially inward of the transfer gear to rotate the transfer gear from the outer side in the radial direction. A casing supporting portion for freely supporting is provided.

Therefore, the opposing driving reaction force between the driving force input point from the transmission and the driving force output point from the transfer can be reliably suppressed, and the rigidity of the transfer drive system including the casing member can be further increased. Can be.

According to a third aspect of the present invention, in the configuration of the second aspect of the invention, the casing support portion is formed of a separate member from the outer casing and is interposed between the transfer gear and the outer casing. It consists of a bearing housing that holds the bearing.

Therefore, the transfer can be assembled from one side in the axial direction at the time of assembling the transfer, so that the assembling workability is greatly improved.

According to a fourth aspect of the present invention, in the configuration of the third aspect of the present invention, the outer casing is divided at least into two parts in the axial direction, and the bearing housing is interposed between the divided outer casings. Interposition is fastened.

Therefore, since the bearing housing functions as a reinforcing member for the outer casing, the rigidity of the entire outer casing is further enhanced.

According to a fifth aspect of the present invention, in the configuration of the third or fourth aspect of the invention, the bearing housing is disposed orthogonal to a drive shaft provided inside the casing member. .

Accordingly, the bearing reaction housing is responsible for the driving reaction force, and the rigidity of the driving system such as the differential gear is further increased.

According to a sixth aspect of the present invention, as a means for solving the above problems, there is provided a transmission having an output shaft arranged in series with a horizontal engine and extending in the vehicle width direction; A center differential and a wheel-to-wheel differential arranged side by side on the axle to be arranged are disposed inside, and one end side is a large-diameter cylindrical body portion, and the other end side is a small-diameter cylindrical body portion externally fitted to the axle, A cylindrical casing member provided with a final ring gear that meshes with an output gear provided on the output shaft at a predetermined reduction ratio on the outer periphery of the large-diameter cylindrical body portion; In the power transmission device for a wheel drive vehicle, the small-diameter cylindrical body side of the casing member is rotatably supported on the outer casing via a roller bearing.

With the above-described structure, the large-diameter cylindrical portion of the casing member is formed by a torque generated when the output power on the transmission side is greatly reduced and the amplified driving force is transmitted to the final ring gear. Even if a falling force acts on the casing member, since the small-diameter cylindrical body portion of the casing member is supported by the roller bearing having a large axial dimension, the supporting rigidity of the casing member can be increased, and the casing member is supported in a cantilever state. Nevertheless, the fall of the casing member can be reliably prevented.

[0019]

Preferred embodiments of the present invention will be described below in detail with reference to the accompanying drawings.

(Overall Configuration of Four-wheel Drive Vehicle) In FIG.
Reference numeral 1 denotes a vehicle body, reference numeral 2 denotes a four-cylinder engine mounted horizontally on a front portion of the vehicle body 1 so that a crankshaft 2a extends in the lateral direction of the vehicle body, and reference numeral 3 denotes a transmission arranged in series with the engine 2. And the transmission 3
Is disposed in an outer casing 4 having a predetermined shape.
An input shaft 6 is connected to and disconnected from the crankshaft 2 a of the engine 2 via a clutch device 5, and an output shaft 7 is disposed in parallel with the input shaft 6. The gear ratio is switched by switching the transmission path of the gear.

On the rear side of the transmission 3, a pair of left and right axles for front wheels (hereinafter referred to as front axle shafts) 8, 8 acting as drive shafts, and a transfer output shaft 9 located behind the front axle shafts. Are arranged in parallel with the input / output shafts 6, 7 of the transmission 3, respectively.
The left and right front axle shafts 8, 8 are respectively connected to joints 10, 10,.
1 are connected to the left and right front wheels 12, 12.

The right end of the transfer output shaft 9 is connected to the front end of a propeller shaft 14 extending in the vehicle longitudinal direction via a bevel gear mechanism 13, and the rear end of the propeller shaft 14 is divided into right and left parts. It is connected to a rear differential 16 on wheel axles (hereinafter referred to as rear axle shafts) 15, 15. The rear differential 16 includes a differential case 18 connected to the propeller shaft 14 via a bevel gear mechanism 17, a pair of pinions 19, 19 supported by the differential case 18, and a pair of left and right rear axle shafts 15 meshing with the respective pinions 19. , 15 and a pair of side gears 20, 20 fixed to the inner ends of the left and right rear axle shafts 15, 15.
And are connected to left and right rear wheels 23, 23 via left and right drive shafts 22, 22, respectively.

On the front axle shafts 8, 8, a center differential 25 and a wheel-to-wheel differential 26 constituting a transfer 24 are arranged in parallel. The center differential 25 distributes power to the front and rear wheels 12 and 23, and the inter-wheel differential 26 distributes power to the front wheels 12 and 12.

Next, a specific structure of the transfer 24 will be described in detail with reference to an enlarged sectional view of FIG.

A differential case 27 of the inter-wheel differential 26 is rotatably fitted on the left and right front axle shafts 8,8. The differential case 27 has cylindrical sleeve portions 27b, 27 on the left and right sides of a hollow spherical main body 27a.
b is provided integrally, and in the main body 27a,
A pair of side gears 28, 28 respectively connected to the left and right front axle shafts 8, 8 and a pinion shaft 29a meshed with each side gear 28 and arranged at right angles to the front axle shafts 8, 8 are attached to the main body 27a. A pair of rotatably supported pinions 29, 29 are fitted.

The center differential 25 includes the differential case 2
7 is rotatably fitted on the left sleeve portion 26b, and the sun gear 30 and the ring gear 31 are supported by a pinion carrier 32.
A double pinion type planetary gear mechanism is meshed and connected via a pinion.

The ring gear 31 extends to the right side so as to cover the main body 26a of the front differential 26. One end of the ring gear 31 is a large-diameter cylindrical body 35b, and the other end is a small-diameter cylindrical body 3b.
A large-diameter cylindrical member corresponding to the sun gear 30 in the casing member 35 is formed on the inner peripheral surface of the large-diameter cylindrical portion 35b corresponding to the sun gear 30 in a substantially cylindrical casing member 35 designated as 5a. A final ring gear 37 that meshes with the output gear 36 of the output shaft 7 of the transmission 3 at a predetermined reduction ratio is formed on the outer peripheral surface of the portion 35b. Further, the casing member 3
The small-diameter cylindrical body 35a in 5 is rotatably fitted to the right sleeve 27b of the differential case 27 in the inter-wheel differential 26 so as to be rotatable. Further, the pinion carrier 32 is rotatably coupled to a differential case 27 of the inter-wheel differential 26.

That is, a final ring gear 37 meshing with the output gear 36 of the output shaft 7 of the transmission 3 is provided inside the casing member 35 formed on the outer peripheral side of the large-diameter cylindrical body 35b. Are arranged coaxially close to and adjacent to each other. With this configuration, it is possible to minimize the axial dimension and the radial dimension of the transfer 24 as much as possible.

Further, the left side of the center differential 25 (that is,
On the front axle shaft 8 (on the side opposite to the inter-wheel differential 26), a transfer gear 38 integrated with the sun gear 30 (in other words, linked) and transmitting power to the rear wheels 23, 23 is arranged. Is. And the sun gear 30
The transfer gear 38 is provided integrally with the sleeve portion 27b of the differential case 27 of the inter-wheel differential 26 so as to rotate integrally therewith. The transfer gear 38 is provided integrally with the transfer output shaft 9 at the left end portion thereof. The gear 39 is meshed.

Further, on the axle 8 on the left side of the transfer gear 38 (ie, on the side opposite to the center differential 25),
A viscous coupling 4 in which silicone oil or the like is sealed in a sealed space formed by the inner cylinder 40a and the outer cylinder 40b.
0 is arranged. The inner cylinder 40a of the viscous coupling 40 is provided in the differential case 2 in the inter-wheel differential 26.
The outer cylinder 40b is rotatably and spline-coupled to the transfer gear 38 while being rotatably and integrally spline-coupled to the sleeve portion 27b. Then, on the differential case 27 between the viscous coupling 40 and the transfer gear 38, a thrust bearing 41 that receives a thrust force of the transfer gear 38 to the left (that is, a direction toward the viscous coupling 40) is arranged. The relative rotation between the differential case 27 of the inter-wheel differential 26 and the transfer gear 38 by the viscous coupling 40 (in other words, the relative rotation of the front and rear wheels 12, 24).
Are regulated.

The small-diameter cylindrical body portion 3 of the casing member 35 extended to the right front axle shaft 8 by a sliding sleeve 42 on the right sleeve portion 27b of the differential case 27 in the inter-wheel differential 26.
5a and a differential case 27 of the inter-wheel differential 26 are rotatably connected to each other, and a mechanical differential lock mechanism 43 for stopping the operation of the center differential 25 is provided. By switching the differential lock mechanism 43 to the locked position, the front and rear wheels are switched. A direct four-wheel drive state is to be obtained.

The transfer output shaft 9 is axially divided into two parts, a solid left shaft 9a and a hollow cylindrical right shaft 9b.
a, 9b, the driving force of the engine 2 is
There is provided a 2 / 4-wheel drive switching mechanism 44 for switching and transmitting only to the front wheel 12 or the front and rear wheels 12, 12, 23, 23. The 2 / 4-wheel drive switching mechanism 44 can also prevent the wheel on the side being lifted from rotating by the action of the viscous coupling 40 when the wheel is towed. In the drawings, reference numerals 45 and 46 denote bearings for rotatably supporting the front axle shafts 8 and 8 on the outer casing 4.

In the above configuration, the output of the engine 2 is
The power is transmitted to a ring gear 31 constituting a center differential 25 via a casing member 35 having a final ring gear 37 meshing with an output gear 36 of an output shaft 7 of the transmission 3 at a predetermined reduction ratio. Distributed to the 23 side.

The output to the front wheel 12 side is transmitted from a pinion carrier 32 constituting the center differential 25 to a front wheel 12 via a wheel-to-wheel differential 26, front wheel axle shafts 8, 8 and left and right drive shafts 11, 11. , 12.

On the other hand, regarding the output to the rear wheel 23 side, the sun gear 30 of the center differential 25
8, transmission gear 39, transfer output shaft 9, bevel gear mechanism 17, propeller shaft 14, rear differential 16, rear axle shafts 15 for rear wheels, right and left drive shafts 22, 22 and the like, and are transmitted to rear wheels 23, 23. Is done.

Further, a rotation difference is generated between the front and rear wheels 12, 23, and the inter-wheel differential 2 connected to the front wheels 12, 12 is rotated.
6 and the transfer gear 38 connected to the rear wheels 23, 23
The driving force is regulated by a viscous coupling 40 interposed between the differential case 27 and the transfer gear 38, and an appropriate driving force is transmitted to the front and rear wheels 12 and 23.

In this embodiment, the outer casing 4 is positioned at a predetermined position (for example, the sun gear 30).
(Position corresponding to the connecting portion between the transfer gear 38)
A pair of divided casings 4 divided in the axial direction
a, 4b.
A bearing housing 46 to be described later is integrally interposed and fastened by bolts 47 between a and 4b. That is, the bearing housing 46 also constitutes a part of the outer casing 4. Further, the bearing housing 46 is provided with a drive shaft (that is, the front axle shaft 8,
8).

As shown in FIG. 3, the bearing housing 46 is formed of a plate-like member having bolt holes 48, 48,... On its outer periphery, and is inserted through an insertion hole 49 through which the transmission 3 is inserted and through the transfer 24. Insertion hole 5
0 and an insertion hole 51 through which the transfer output shaft 9 is inserted. And, this bearing housing 46
Serves as a casing supporting portion that is located radially inward of the final ring gear 37 and rotatably supports the transfer gear 38 from the outside in the radial direction. The gap between the transfer gear 38 and the bearing housing 46 is , A ball bearing 52 is interposed.

The small-diameter cylindrical portion 35a of the casing member 35 is rotatably supported via roller bearings 53 on the inner peripheral surface of one of the divided casings 4a constituting the outer casing 4. Here, the roller bearing 53 is used because the axial proof stress can be increased as compared with the ball bearing.
This is because the support rigidity of No. 5 can be further increased. Therefore, the support rigidity of the casing member 35 supported in a cantilever state is increased.

With the above structure, the opposing driving reaction force between the driving force input point from the transmission 3 (that is, the final ring gear 37) and the driving force output point (the transfer gear 38) from the transfer 24 is ensured. , And the support rigidity of the transfer drive system including the casing member 35 can be further increased.

In the case of the present embodiment, after assembling the front wheel differential 26, the center differential 25, and the viscous coupling 40 in advance into one of the divided casings 4a in the outer casing 4, the ball bearing 52 is mounted. And the bearing housing 46, and then the other divided casing 4b is bolted up with respect to the divided casing 4a.
The transfer can be assembled (that is, the transfer can be assembled from one side in the axial direction). That is, the assembly workability is greatly improved. In addition, the bearing housing 46 is connected to the divided casing 4 of the outer casing 4.
Since the a and 4b are interposed and fastened, the bearing housing 46 functions as a reinforcing member for the outer casing 4, and the rigidity of the entire outer casing 4 is further increased.

Further, since the bearing housing 46 is arranged orthogonal to the drive shaft (ie, the front axle shaft 8) disposed inside the casing member 35,
The drive reaction force is taken over by the bearing housing 46, and the rigidity of the drive system such as the differential is further increased.

In the above embodiment, the bearing housing for supporting the outside of the transfer gear is formed of a member separate from the outer casing. However, the bearing housing is formed integrally with the outer casing. Is also good. In this case, since the transfer must be assembled from both sides of the bearing soldering, the assembling workability is deteriorated as compared with the present embodiment.

[0044]

According to the first aspect of the present invention, the casing member in which the center differential and the inter-wheel differential are arranged, and the transfer gear linked to the center differential and transmitting the driving force to the other axle are arranged side by side. In addition, since the transfer gear is rotatably supported with respect to the outer casing, in a power transmission device in which the casing member and the transfer gear are provided side by side, the casing member can be provided without increasing the axial dimension. There is an excellent effect that the support rigidity of the transfer drive system including the above can be greatly increased.

According to the second aspect of the present invention, the outer casing is provided with the casing supporting portion which is located radially inside the transfer gear and rotatably supports the transfer gear from the outside in the radial direction. The opposing driving reaction force between the driving force input point from the transmission and the driving force output point from the transfer is reliably suppressed, and the support rigidity of the transfer drive system including the casing member can be further increased.

According to the third aspect of the present invention, since the casing supporting portion is formed of a separate member from the outer casing, and is constituted by the bearing housing for holding the bearing interposed between the outer casing and the transfer gear. At the time of transfer assembling, assembly from one side in the axial direction becomes possible, and assembling workability is greatly improved.

According to the fourth aspect of the present invention, the outer casing is divided into at least two parts in the axial direction, and the bearing housing is interposed and fastened between the divided outer casings. , The rigidity of the entire outer casing is further enhanced.

According to the fifth aspect of the present invention, since the bearing housing is arranged in a state orthogonal to the drive shaft provided inside the casing member, the drive reaction force is covered by the bearing housing. The support rigidity of the drive system is further enhanced.

According to the sixth aspect of the present invention, the small-diameter cylindrical body side of the casing member in which the center differential and the inter-wheel differential are disposed is rotatably supported on the external casing via the roller bearing. Therefore, the support rigidity of the casing member can be increased, and there is an excellent effect that the fall of the casing member can be reliably prevented despite being supported in a cantilevered state.

[Brief description of the drawings]

FIG. 1 is a schematic plan view showing an overall configuration of a power transmission system of a four-wheel drive vehicle according to an embodiment of the present invention.

FIG. 2 is an enlarged sectional view showing a main part of a power transmission device for a four-wheel drive vehicle according to the embodiment of the present invention.

FIG. 3 is an enlarged front view of bearing housing in the power transmission device for the four-wheel drive vehicle according to the embodiment of the present invention.

[Explanation of symbols]

2 is an engine, 3 is a transmission, 4 is an outer casing, 4a and 4b are split casings, 7 is an output shaft, 8
Is an axle (front axle shaft), 9 is a transfer output shaft, 24 is a transfer, 25 is a center differential, 26 is a differential between wheels, 35 is a casing member, 35a is a small-diameter cylindrical body, 35b is a large-diameter cylindrical body, and 36 is a large-diameter cylindrical body. An output gear, 37 is a final ring gear, 38 is a transfer gear, 46 is a bearing housing, 52 is a ball bearing, and 53 is a roller bearing.

Claims (6)

[Claims] 1. An in-line engine for a horizontal engine,
A transmission having an output shaft extending in the vehicle width direction, a center differential and an inter-wheel differential arranged side by side on the axle arranged in parallel with the output shaft are disposed inside, one end side is a large-diameter cylindrical body portion, and the other end is provided. A small-diameter cylindrical portion is fitted on the axle, and a final ring gear meshing with an output gear provided on the output shaft at a predetermined reduction ratio is provided on an outer periphery of the large-diameter cylindrical portion. What is claimed is: 1. A power transmission device for a four-wheel drive vehicle, comprising: a tubular casing member disposed in an outer casing, the transfer gear being linked to the casing member and the center differential and transmitting a driving force to the other axle. Wherein the transfer gear is rotatably supported with respect to the outer casing. 2. The apparatus according to claim 1, wherein the outer casing is provided with a casing supporting portion which is located radially inside the transfer gear and rotatably supports the transfer gear from the outside in the radial direction. Claim 1
A power transmission device for a four-wheel drive vehicle as described in the above. 3. The apparatus according to claim 2, wherein the casing support portion is formed of a separate member from the outer casing, and is constituted by a bearing housing for holding a bearing interposed between the transfer gear and the casing support portion. Item 4. A power transmission device for a four-wheel drive vehicle according to Item 2. 4. The outer casing is divided into at least two in an axial direction, and the bearing housing is
The power transmission device for a four-wheel drive vehicle according to claim 3, wherein an intervening fastening is provided between the divided outer casings. 5. The bearing according to claim 3, wherein the bearing housing is disposed orthogonal to a drive shaft disposed inside the casing member.
The power transmission device for a four-wheel drive vehicle according to any one of the preceding claims. 6. An in-line engine for a horizontal engine,
A transmission having an output shaft extending in the vehicle width direction, a center differential and an inter-wheel differential arranged side by side on the axle arranged in parallel with the output shaft are disposed inside, one end side is a large-diameter cylindrical body portion, and the other end is provided. A small-diameter cylindrical portion is fitted on the axle, and a final ring gear meshing with an output gear provided on the output shaft at a predetermined reduction ratio is provided on an outer periphery of the large-diameter cylindrical portion. A power transmission device for a four-wheel drive vehicle in which a cylindrical casing member is disposed in an outer casing, wherein the small-diameter cylindrical body side of the casing member is provided with a roller bearing with respect to the outer casing. A power transmission device for a four-wheel drive vehicle, which is rotatably supported.