JPH10100706A - Power transmission device for four-wheel drive car - Google Patents

Abstract

PROBLEM TO BE SOLVED: To widen the degree of freedom in the layout of constituent elements of a power transmission device and prevent effectively the tooth bearing of a hypoid ring gear which transmits the driving force to a propeller shaft. SOLUTION: A hypoid ring gear to transmit the driving force to the rear wheels through a propeller shaft is installed between the first and second power transmitting mechanisms 54 and 55, wherein the first power transmitting mechanism 54 consists of the first aux. shafts 51 and 52 installed parallel with the first axles 10 and 11 for the front wheels and a pair of spur wheels 54a and 54b which transmit to the first aux. shaft 51 the driving force given from the output element to the second wheel side of an inter-axle differential device 20 while the second power transmitting mechanism 55 consists of a pair of spur wheels 55a and 55b to transmit to the second aux. shaft 52 the driving force fed to the first aux. shaft 51.

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 that transmits driving force of an engine mounted on a vehicle body to a front wheel and a rear wheel.

[0002]

2. Description of the Related Art Conventionally, as disclosed in Japanese Patent Application Laid-Open No. 61-60329, a differential or a power distribution device is provided in a transmission of an automobile having a first axle and a second axle. In an automobile driving device, the two axles are connected to an output member, and a differential limiting device including a liquid friction clutch or the like is provided between the first and second axles.
The differential limiting device is configured as an independent structural unit, and both portions to be connected (connecting members) are each connected to one of the two output members (hollow gear and sun gear) of the differential device by a speed increasing spur gear transmission. There is known one configured to be driven via a motive.

[0003] According to the above configuration, the liquid friction clutch is installed on the auxiliary shaft installed in parallel with the first axle at a position away from the differential device. The liquid friction clutch can be easily replaced, and the liquid friction clutch can be downsized by reducing the driving force input from the first axle to the liquid friction clutch.

[0004]

In the vehicle driving device described in the above publication, the driving force input to the sun gear (sun gear) of the differential device is transmitted to the auxiliary device by a pair of power transmission mechanisms composed of spur gears. After being transmitted to the shaft, it is configured to be input to a propeller shaft (cardan shaft) by an angular transmission mechanism including a bevel gear and the like. When the above-mentioned angular transmission mechanism is used for a vehicle, a hypoid gear is generally used because of its quietness. However, since the hypoid gear has a large slip on the tooth surface, the efficiency is slightly inferior, and the seizure tends to occur. Therefore, it is necessary to provide an appropriate offset and twist between the hypoid ring gear constituting the hypoid gear mechanism and the hypoid pinion so as to prevent this.

[0005] Therefore, the gear ratio of the hypoid gear mechanism is set to a substantially constant value, and the gear ratio of the pair of spur gears is set to the reduction ratio of the differential gear in order to match the rotational speeds of the front wheels and the rear wheels. Therefore, despite the fact that the differential limiting device including the above-mentioned liquid friction clutch is installed independently of the differential device, the degree of freedom of the layout is limited and the difference is limited. Units for motion limiting devices, etc.
There is a problem that there is little room for selecting each component constituting the vehicle drive device.

Further, in the driving apparatus for an automobile described in the above publication, the spur gear forming the power transmission mechanism and the liquid friction clutch are mounted on a shaft on which the hypoid ring gear forming the angle transmission mechanism is installed. Since the pinion for inputting the driving force is installed in the differential limiting device consisting of :, the total length of the shaft is inevitably increased, and the reaction force when transmitting the driving force from the hypoid ring gear to the propeller shaft is inevitable. Therefore, there is a problem that the shaft is easily bent and the tooth contact of the hypoid ring gear is easily changed.

Although it is not a solution directly to the above-mentioned problem, there is known a layout in which a pair of sub-axes are laid out in parallel with the first axle as shown in Japanese Patent Application Laid-Open No. 58-12830. ing. According to this configuration, it is possible to increase the degree of freedom of the layout of each of the above-described components to some extent, but unless the installation position of the hypoid ring gear on the countershaft is properly considered, the teeth of this hypoid ring gear Countermeasures against hits cannot be implemented effectively.

In view of such circumstances, the present invention can increase the degree of freedom in laying out each element of the power transmission device with a simple configuration, and also provides a hypoid ring for transmitting a driving force to a propeller shaft. An object of the present invention is to provide a power transmission device for a four-wheel drive vehicle that can appropriately take measures against gear contact.

[0009]

The invention according to claim 1 is
A transmission connected to an output shaft of an engine mounted horizontally on a vehicle body, and a first wheel for driving a first wheel disposed at a position closer to the engine among front wheels or rear wheels.
An axle; a second axle for driving a second wheel disposed at a position away from the engine among the front wheels or the rear wheels;
A first power transmission mechanism including first and second subshafts arranged in parallel with the axle, and a pair of spur gears transmitting a part of the driving force output from the transmission to the first subshaft;
A second power transmission mechanism comprising a pair of spur gears for transmitting the driving force input to the first countershaft to the second countershaft, and transmitting the driving force input to the second countershaft to the vehicle body. A hypoid ring gear for transmitting to the second wheel side via a propeller shaft extending in the front-rear direction is provided on the second sub shaft, and a hypoid ring gear is provided between the first power transmission mechanism and the second power transmission mechanism in the vehicle width direction. The hypoid ring gear is provided.

[0010] According to the above configuration, after a part of the driving force output from the transmission from the engine is input to the first sub shaft through the first power transmission mechanism, the second power is transmitted from the first sub shaft to the second sub shaft. The power is input to the second subshaft via a power transmission mechanism, and is transmitted to the second axle side via a hypoid ring gear disposed between the first power transmission mechanism and the second power transmission mechanism. The driving force will be transmitted.

According to a second aspect of the present invention, in the power transmission device for a four-wheel drive vehicle according to the first aspect, the bearing member for supporting the installation portion of the hypoid ring gear of the second countershaft is provided with the first power supply. This is provided between the transmission mechanism and the second power transmission mechanism.

According to the above configuration, the total length of the second countershaft on which the hypoid ring gear is installed is reduced, and the second countershaft is supported by the bearing member near the installation portion of the hypoid ring gear. In addition, the bending of the second sub-shaft due to the reaction force when the driving force is transmitted from the hypoid ring gear to the propeller shaft is effectively suppressed.

[0013]

1 and 2 show an embodiment of a power transmission device for a four-wheel drive vehicle according to the present invention. An engine 1, a transmission 2 provided in a transmission case 2a connected to one end of the four-wheel drive vehicle, and a transfer device 3
And are installed.

The engine 1 is mounted on a vehicle body in a horizontal state, and is installed such that an output shaft 4 extends in the vehicle width direction. The transmission 2 includes a clutch 5
An input shaft 6 connected to the output shaft 4 of the engine 1 via a driving force transmitting means composed of the following, and an output shaft 7 parallel to the input shaft 6 are arranged to extend in the vehicle width direction. Further, between the input shaft 6 and the output shaft 7 of the transmission 2, there are provided a transmission gear train 8 for the 1st to 5th speed and the reverse speed, which are selectively in a power transmission state, and the output shaft 7. The transmission 2 has an end on the clutch 5 side.
An output gear 9 for transmitting a driving force to the transfer device 3 side is provided.

The transfer device 3 divides the driving force inputted from the transmission 2 and arranges the left front wheel 12 and the right front wheel 13 disposed at positions close to the engine 1 via the first left and right axles 10 and 11. And a rear wheel (differential differential between second wheels) 15 extending from the propeller shaft 14 extending in the front-rear direction of the vehicle and a rear wheel 15 separated from the engine 1 via left and right second axles 16 and 17. Is configured to drive a second wheel including a left rear wheel 18 and a right rear wheel 19 disposed in the vehicle.

That is, as shown in FIGS. 2 and 3, the transfer device 3 is a center differential (differential device between axles) 20 including a planetary gear mechanism disposed on the axis of the first axles 10 and 11. A front differential (first inter-wheel differential device) 30 including a bevel gear mechanism;
First and second countershafts 51 and 52 installed in parallel with 0 and 11
The differential limiting device including the viscous coupling 40 is disposed on the first counter shaft 51.

The viscous coupling 40 is a kind of viscous clutch that transmits a driving force by using the shear resistance of a viscous fluid made of silicon oil or the like. The viscous coupling 40 is provided at the end of the first sub shaft 51 on the engine 1 side. The inner case 41 fixed by a means such as spline coupling and the outer case 42 connected to the first axle 11 while being rotatably supported by the first sub shaft 51 and rotating integrally with each other. ,
The viscous fluid is agitated according to the rotation difference generated during this time, so that a shear force is generated. This allows
When the outer case 42 rotates rapidly in response to slippage of the front wheels 12, 13, the front wheels 12, 13 and the rear wheel 1
The driving force according to the rotation difference between the front wheels 12 and 13 is automatically distributed to the rear wheels 18 and 19, and the front wheels 12 and 13 are used for cornering or the like.
In addition, while allowing the rotation difference (differential) between the rear wheels 18 and 19 to some extent to suppress the occurrence of the braking phenomenon, excessive differential operation is suppressed and the running stability is ensured. I have.

Instead of the viscous coupling 40 utilizing the shear resistance of the viscous fluid, a rotary blade cup which transmits driving force to the rear wheels 18 and 19 using static pressure generated when compressing the fluid. The differential limiting device may be configured by a ring or the like. This rotary blade coupling is composed of a pressure generating portion and a torque transmitting portion.In the pressure generating portion, when a rotation difference occurs between the front and rear wheels, the tri-blade coupled to the shaft rotates relative to the housing, High viscosity silicone oil is made to flow.

The center differential 20 includes a differential case including a center differential case 29, a ring gear 21 integrally formed on an inner peripheral portion thereof,
1, a plurality of first pinions 22 meshing with the first pinions 22, a plurality of second pinions 23 respectively meshing with the first pinions 22, and pinion shafts 24, 2
A double pinion type planetary gear mechanism constituted by a pinion carrier 26 that supports the first and second pinions 22 and 23 through the sun gear 5, and a sun gear 27 that meshes with the second pinion 23, respectively.

The center differential case 29 of the center differential 20 includes a clutch housing 5 for housing the clutch 5 disposed between the engine 1 and the transmission 2.
1a is installed along the space created on the transmission 2 side (see FIG. 1). An input gear 28 integrally attached to an outer peripheral portion of the center differential case 29 by a bolt or the like is connected to the output gear 9 provided at an end of the output shaft 7 provided on the transmission 2 on the clutch 5 side. The driving force from the transmission 2 is input to the ring gear 21 of the center differential 20 via the output gear 9 and the input gear 28.

The front differential 30 is provided with a center differential 20.
A front differential case 31 integrally formed with a pinion carrier 26, which is one of the output elements, and a pinion shaft 32 installed in the front differential case 31 in a direction orthogonal to the axis of the first axles 10 and 11.
A pair of pinions 33 and 34 composed of bevel gears rotatably supported by the pinion shaft 32;
3 and 34, a pair of left and right side gears 35 and 36 formed of bevel gears meshing with each other.
Ends of the first left and right axles 10 and 11 are integrally connected to the first and second axles 5 and 36, respectively.

The front differential 30 is coaxial with the center differential 20, that is, the first axle 10,
On the transmission 11 side of the center differential 20, it is installed in the center differential case 29. Further, a cylindrical shaft 53 extending toward the installation portion of the engine 1 is integrally formed with the sun gear 27 which is one output element of the center differential 20.
A spur gear 54 a constituting the first power transmission mechanism 54 is formed integrally with an extended end of the cylindrical shaft 53.

A spur gear 54b meshing with the spur gear 54a is integrally formed at an intermediate portion of the first sub shaft 51, or integrally connected by means such as spline connection. A spur gear 55 that constitutes a second power transmission mechanism 55 is provided on the transmission 2 side of the first sub shaft 51.
a is integrally provided, and the spur gear 55a is meshed with a spur gear 55b integrally provided on the transmission 2 side of the second counter shaft 52.

A hypoid ring gear 56a is integrally mounted on the side of the engine 1 of the second countershaft 52 by means such as spline coupling, and the hypoid ring gear 56a is installed in the longitudinal direction of the vehicle body. A third power transmission mechanism 56 is meshed with a hypoid pinion 56b fixed to one end of the output shaft 58, and is formed by the hypoid ring gear 56a and the hypoid pinion 56b. The output shaft 58 is connected to the propeller shaft 14 as shown in FIG.
The driving force input to the output shaft 58 is output to the rear wheels 18 and 19.

The left and right ends of the second counter shaft 52 are supported by bearing members 57a and 57b. Then, on the side of the installation portion of the hypoid ring gear 56a, the second
A bearing member that supports the countershaft 52, that is, a bearing member 57 b located at the end of the second countershaft 52 on the engine 1 side includes a spur gear 54 b configuring the first power transmission mechanism 54 and a second
The bearing member 57b is disposed on the transmission 2 side of the spur gear 54b in the vehicle width direction by being disposed between the power transmission mechanism 55 and the spur gear 55a.

The first axle 11 for the right front wheel 13 includes:
An output gear 61 for outputting a driving force is fixed to the outer case 42 of the viscous coupling 40, and the output gear 61 is meshed with an input gear 62 provided integrally with the outer case 42, whereby the first The outer case 42 of the viscous coupling 40 is driven to rotate according to the driving force of the axle 11.

As shown in FIG. 4, the axis of the first sub shaft 51 is disposed above the vehicle body with respect to the axis of the first axle 51. The axis of the second counter shaft 52 is the first
It is arranged below the axis of the axle 51.

In the above configuration, the driving force output from the engine 1 via the clutch 5 and the transmission 2 is transmitted from the output gear 9 of the transmission 2 via the input gear 28 to the ring gear 21 of the center differential 20 in the transfer device 3. At the center differential 20, the sun gear 27 and the pinion gear 26
And transmitted to each of the output elements.

The driving force transmitted to the sun gear 27 is transmitted to the first power transmission mechanism 5 via the cylindrical shaft 53.
4, second power transmission mechanism 55, third power transmission mechanism 5
6, is input to the rear differential 15 via the output shaft 58 and the propeller shaft 14, and is further divided right and left by the rear differential 15, and then drives the right and left rear wheels 18, 19 via the second left and right axles 16, 17. Will do. The driving force input to the spur gear 54 a of the first power transmission mechanism 54 is transmitted to the inner case 41 of the viscous coupling 40 via the first sub shaft 51.

The driving force transmitted to the pinion carrier 26 is input to the front differential case 31 of the front differential 30, and further divided at the front differential 30 into left and right first differentials. The left and right front wheels 12, 13 are driven via the axles 10, 11. By driving the left and right front wheels 12 and 13 and the left and right rear wheels 18 and 19 in this manner, the vehicle
The wheels are driven. The driving force input to the first axle 11 is transmitted to the outer case 42 of the viscous coupling 40 via the output gear 61 and the input gear 62.

At the time of cornering or the like, the first
The differential operation of the viscous coupling 40 interposed between the axle 11 and the first sub shaft 51 suppresses the occurrence of a braking phenomenon, and the power transmission of the viscous coupling 40 causes the center differential 20 to rotate. Is limited, and running stability at the time of cornering or the like is ensured.

As described above, the first and second countershafts 51, 52 are installed in parallel with the first axle 11 for the front wheels 12, 13, and the center differential 2, which is an output element to the rear wheels 18, 19, is provided.
0 sun gear 27 and the first sub shaft 5
1 and the first sub-shaft 51 and the second sub-shaft 52 are interlocked with each other by a second power transmission mechanism 55 while the first and second sub-shafts 51 and 52 are interlocked with each other by a first power transmission mechanism 54. Hypoid ring gear 56 constituting third power transmission mechanism 56 for transmitting driving force
a is provided on the second counter shaft 52, and the hypoid ring gear 5
6a via the propeller shaft 14 and the like
Since the driving force is configured to be transmitted to the sides 8 and 19, the degree of freedom in layout can be increased as described below by appropriately selecting the gear ratio of the first and second power transmission mechanisms 54 and 55. Can be.

That is, the spur gear 54 corresponds to the deceleration of the axle differential including the center differential 20.
The gear ratio of the first power transmission mechanism 54 composed of the first and second power transmission mechanisms 55a and 54b and the gear ratio of the second power transmission mechanism 55 composed of the spur gears 55a and 55b are changed to appropriate values. , 13 and the rear wheels 18, 19 while maintaining the same rotational speed, the distance between the first axle 11 and the first sub shaft 51, and the first sub shaft 51 and the second sub shaft 5.
2 can be arbitrarily set, and the driving force input to the viscous coupling 40 can be arbitrarily changed. Therefore, for example, units having various external shapes and capacities can be used as the viscous coupling 40 disposed between the first axle 11 and the first sub shaft 51, and the viscous coupling 40 is composed of the viscous coupling. The degree of freedom in selecting each component of the power transmission device can be increased.

Further, as shown in FIG.
1 is disposed above the first axle 11 and is disposed below the first axle 11 of the second sub shaft 52, whereby the viscous coupling 40 which is easily affected by heat is provided.
Can be separated from the exhaust pipe 63 and the exhaust gas purification device 64 disposed below the floor of the vehicle body to protect the viscous coupling 40 from heat damage of the exhaust gas purification device 64 and the like. A propeller shaft 1 connected to a hypoid ring gear 56 a provided on the second counter shaft 52 via the hypoid pinion 56 b and the output shaft 58.
4 can be disposed on the lower side of the vehicle body so that the weight of the vehicle body can be positioned below.
Can be prevented from protruding largely into the vehicle interior.

As described above, in the vehicle width direction,
Spur gear 54b constituting the first power transmission mechanism 54
A hypoid ring gear 56a constituting the third power transmission element 56 is disposed between the spur gear 55a constituting the second power transmission mechanism 55 and the spur gear 55a constituting the second power transmission mechanism 55.
The hypoid ring gear 56a can be installed by utilizing the space formed between 4b and 55a, and the overall length of the second sub shaft 52 can be shortened.
Therefore, it is possible to effectively prevent a change in the tooth contact of the hypoid ring gear 56a that transmits the driving force to the propeller shaft 14 by suppressing the bending deformation of the second sub shaft 52.

Further, the spur gears 54b, 55a are provided on both sides in the vehicle width direction of the hypoid ring gear 56a meshing with the hypoid pinion 56b on the output shaft 58 provided along a center line extending in the front-rear direction of the vehicle body. Is arranged, when the driving force input to the spur gears 54b and 55a changes according to the vehicle type, etc., the shape of the transfer case in which these gears are arranged is not changed, and Spur gears 54b, 55a corresponding to the driving force
Can be easily changed.

In the above embodiment, the bearing member 57b supporting the installation portion of the hypoid ring gear 56a of the second countershaft 52 is connected to the first power transmission mechanism 54 and the second power transmission mechanism 55. Since the second sub shaft 52 is disposed on the transmission 2 side of the spur gear 54b, the overall length of the second sub shaft 52 can be reduced as much as possible, and the bending deformation thereof can be suppressed more effectively.

That is, as shown in FIG.
2, the bearing member 57b located on the engine 1 side may be disposed on the engine 1 side of the spur gear 54b constituting the first power transmission mechanism 54, but in such a case, Since the total length of the second countershaft 52 is increased by an amount corresponding to the tooth thickness of the spur gear 54b, the reaction force when transmitting the driving force from the hypoid ring gear 56a to the propeller shaft 14 increases the second countershaft 52. Tend to bend, and the tooth contact of the hypoid ring gear 56a tends to change. Therefore, as described above, the second sub shaft 5
It is desirable to adopt a configuration in which a bearing member 57b that supports the installation portion side of the second hypoid ring gear 56a is disposed between the first power transmission mechanism 54 and the second power transmission mechanism 55.

Further, as shown in the above embodiment, the center differential 2 is provided on the transmission 2 side of the clutch housing 5a for accommodating the driving force transmitting means comprising the clutch 5.
0 and a center differential case 29 in which a front differential 30 is disposed, and a differential case is provided on the engine 1 side of the clutch housing 5a.
When the spur gear 54a of the first power transmission mechanism 54 and the input gear 61 of the viscous coupling 40 are disposed, the center differential case 29 is disposed in a space formed on the transmission 2 side of the clutch housing 5a. The spur gear 54a and the input gear 61 constituting the first power transmission mechanism 54 can be installed while avoiding the clutch housing 5a having a large outer shape. Therefore, despite the fact that the center differential 20 is formed by the planetary gear mechanism having a relatively large outer shape, the overall size of the device in the front-rear direction of the vehicle body can be reduced by bringing the center differential 20 closer to the installation portion side of the engine 1. can do.

Further, since the differential limiting device including the viscous coupling 40 for limiting the differential between the first axle 11 and the first sub shaft 51 is provided on the first sub shaft 51, the viscous coupling 40 As in the case where is disposed on the first axle 11, there is no possibility that the viscous coupling 40 interferes with the engine 1, and in this respect, the degree of freedom of the layout can be increased.

In the above embodiment, an example was described in which the center differential 20 housed in the center differential case 29 and the differential limiting device including the viscous coupling 40 were disposed on the first axle 11. Alternatively, the differential limiting device may be provided on the propeller shaft 14 and the center differential may be omitted.

In the above embodiment, the present invention is applied to a four-wheel drive vehicle provided with a manual transmission type transmission 2 in which a driving force transmitting means comprising a clutch 5 is disposed at one end of the engine 1. I explained an example that did
The present invention is also applicable to a four-wheel drive vehicle provided with an automatic transmission type transmission in which a torque converter is provided instead of the clutch 5.

[0043]

As described above, according to the present invention, the first and second sub shafts are provided in parallel with the first axle, and a part of the driving force output from the transmission is transmitted to the first sub shaft. A first power transmission mechanism composed of a pair of spur gears, a second power transmission mechanism composed of a pair of spur gears for transmitting the driving force input to the first sub shaft to the second sub shaft, and A hypoid ring gear for transmitting the driving force input to the second countershaft to the second wheel is disposed between the first power transmission mechanism and the second power transmission mechanism in the vehicle width direction. By changing the gear ratios of the first and second power transmission mechanisms including the pair of spur gears to appropriate values, the first and second power transmission mechanisms can be set to have the same rotational speed between the front wheels and the rear wheels while maintaining the same rotational speed. Arbitrary setting of axle, first countershaft and second countershaft spacing And the thickness of the spur gear can be changed in accordance with the driving force without changing the shape of the transfer case in which the gears are disposed, and the deflection of the second axle can be changed. There are advantages that deformation can be suppressed.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing an overall configuration of a power transmission device for a four-wheel drive vehicle according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing a configuration of a main part of the power transmission device.

FIG. 3 is a plan sectional view showing a configuration of a main part of the power transmission device.

FIG. 4 is a side sectional view showing a configuration of a main part of the power transmission device.

FIG. 5 is a cross-sectional view showing another embodiment of the power transmission device for a four-wheel drive vehicle according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Engine 2 Transmission 10,11 1st axle 12,13 Front wheel (1st wheel) 14 Propeller shaft 16,17 2nd axle 18,19 Rear wheel (2nd wheel) 51 1st subshaft 52 2nd subshaft 54th 1 power transmission mechanism 54a, 54a, 55a, 55b spur gear 55 second power transmission mechanism 56a hypoid ring gear 57a bearing member

Claims (2)

[Claims] 1. A transmission connected to an output shaft of an engine mounted horizontally on a vehicle body, and a first axle for driving a first wheel disposed at a position closer to the engine among front wheels or rear wheels. A second axle for driving a second wheel disposed at a position distant from the engine among the front wheels or the rear wheels, first and second subshafts arranged in parallel with the first axle, and A first power transmission mechanism comprising a pair of spur gears for transmitting a part of the output driving force to the first countershaft;
A second power transmission mechanism comprising a pair of spur gears for transmitting to the countershaft, wherein the driving force input to the second countershaft is transmitted to the second wheel side via a propeller shaft extending in the front-rear direction of the vehicle body. A hypoid ring gear for transmission is provided on the second countershaft, and the hypoid ring gear is disposed between the first power transmission mechanism and the second power transmission mechanism in the vehicle width direction. Power transmission device for wheel drive vehicles. 2. The power transmission system according to claim 1, wherein a bearing member for supporting the hypoid ring gear installation portion of the second countershaft is disposed between the first power transmission mechanism and the second power transmission mechanism. The power transmission device for a four-wheel drive vehicle according to claim 1.