JP3620962B2 - Vehicle transfer device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a vehicle transfer device, in particular, a power output from an output shaft of a transmission, with a rear wheel drive output shaft in series with the transmission output shaft and a front wheel drive output in parallel with the rear wheel drive output shaft. The present invention relates to a vehicle transfer device provided with a coupling for distributing differential torque between a rear wheel drive output shaft and a front wheel drive output shaft.
[0002]
[Prior art]
Conventionally, a vehicular transfer device that can change a part-time type to a full-time type without changing the transfer case has been proposed in, for example, Japanese Patent Application Laid-Open No. 9-11765. This transfer device distributes the power output from the output shaft of the transmission to the rear wheel drive output shaft in series with the transmission output shaft and the front wheel drive output shaft in parallel with the rear wheel drive output shaft. In addition, a coupling for transmitting a differential torque between the rear wheel drive output shaft and the front wheel drive output shaft is provided.
[0003]
[Problems to be solved by the invention]
In the case of the above transfer device, in order to stably support the rear wheel drive output shaft, a bearing for supporting the rear portion of the rear wheel drive output shaft with respect to the transfer case and a boss portion for switching two wheels and four wheels are transferred. A bearing that is pivotally supported with respect to the case, a bearing that is disposed between the boss portion and the rear wheel drive output shaft, a bearing that is disposed between the outer member of the coupling and the rear wheel drive output shaft, and an inner of the coupling A number of bearings are used such as a bearing that pivotally supports the front end of the member with respect to the transfer case. Therefore, there is a problem that the number of parts and the axial dimension are increased.
[0004]
Further, when the chain drive sprocket is supported on the rear wheel drive output shaft, the tooth portion engaged with the chain may be offset in the axial direction with respect to the support portion in order to shorten the axial dimension. In this case, the falling force acts on the sprocket due to the chain load, the meshing with the chain becomes worse, the tooth surface wear and rotational resistance increase, and between the inner race that supports the sprocket in rotation. Wear is likely to occur. In order to solve such a problem, a needle bearing is provided on the inner peripheral side of the chain drive sprocket. However, the needle bearing does not necessarily have sufficient support rigidity against the above-described tilting force.
[0005]
SUMMARY OF THE INVENTION An object of the present invention is to provide a vehicle transfer device that can reduce the number of bearings as much as possible and reduce the axial dimension.
Another object of the present invention is to provide a vehicular transfer device that can prevent the inclination of the front wheel drive sprocket with a simple structure.
[0006]
[Means for Solving the Problems]
In order to achieve the above object, according to the first aspect of the present invention, there is provided a rear wheel drive output shaft in series with a transmission output shaft, and a rear wheel drive output shaft. In the vehicle transfer device provided with a coupling that distributes the differential torque between the output shaft for driving the rear wheels and the output shaft for driving the front wheels, in addition to the output shaft for driving the front wheels in parallel with the output shaft for driving the rear wheels. A first bearing for pivotally supporting the shaft with respect to the transfer case and a second bearing for pivotally supporting the outer member of the coupling with respect to the transfer case are provided, and the output shaft for driving the front wheels is disposed on the output shaft for driving the rear wheels. The chain drive sprocket that drives the wheel is rotatably supported, the outer member of the coupling is connected to the chain drive sprocket so as to rotate together, and the front end of the rear wheel drive output shaft is the cup. Provided is a vehicle transfer device that is connected to a rear end portion of a transmission output shaft via an inner member of a coupling, and the output shaft for driving a rear wheel and an inner member of a coupling are press-fitted. To do.
[0007]
According to a second aspect of the present invention, the power output from the output shaft of the transmission is transmitted to the rear wheel drive output shaft in series with the transmission output shaft and the front wheel drive in parallel with the rear wheel drive output shaft. In a vehicle transfer device provided with a coupling that distributes to the output shaft for driving and transmits a differential torque between the output shaft for driving the rear wheels and the output shaft for driving the front wheels, a bearing is provided at the rear portion of the outer member of the coupling. A boss portion rotatably supported by the transfer case via the boss portion, and an inner spline portion formed inside the boss portion, the chain drive sprocket for driving the front wheel drive output shaft on the rear wheel drive output shaft And a toothed portion that is supported in an offset state on the rear side in the axial direction, a press-fitting fitting portion that is press-fitted to the boss portion of the coupling into the front portion of the sprocket, and an inner spline portion of the coupling To provide a vehicle transfer apparatus characterized by an outer spline portion fitted is formed.
[0008]
In the first aspect of the invention, the rear portion of the rear-wheel drive output shaft is pivotally supported by the first bearing, and the front portion of the rear-wheel drive output shaft is press-fitted to the inner member of the coupling. Since it is pivotally supported by the second bearing via the member, the rear-wheel drive output shaft is supported at two points in the front-rear direction, and a stable support structure can be obtained. Moreover, since two bearings are sufficient, it is possible to reduce the number of parts and the axial dimension.
[0009]
In the invention of claim 2, the boss provided on the outer member of the coupling is rotatably supported by the transfer case via the bearing, and the boss is press-fitted to the chain drive sprocket. Even if the drive sprocket is supported on the rear wheel drive output shaft in an offset state, the tilt can be prevented and problems such as tooth surface wear and increased rotational resistance can be eliminated. Moreover, since no special bearing is required, an increase in the number of parts can be prevented.
[0010]
If the press-fitting part of the sprocket is press-fitted into the outer peripheral surface of the boss part of the coupling into which the bearing is press-fitted as in claim 3, the sprocket is press-fitted using the bearing fitting part of the boss part. Therefore, the sprocket fitting portion can be processed simultaneously with the bearing fitting portion, which is advantageous in terms of cost.
[0011]
In the present invention, the coupling is not limited to the fluid coupling and may be a differential mechanism such as a center differential as long as it transmits a differential torque between the rear wheel driving output shaft and the front wheel driving output shaft. May be.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
1 and 2 show a first embodiment of the present invention.
In FIG. 1, 1 is a transmission, 2 is a transmission output shaft, and 3 is a vehicle transfer device. The transfer device 3 is a full-time type, and in the transfer cases 4 and 5, a rear wheel drive output shaft 6 is rotatably supported by a bearing 7, and a front wheel drive output shaft 8 is a bearing 9, 10 is rotatably supported. The rear wheel drive output shaft 6 is disposed in series with the transmission output shaft 2, and the front wheel drive output shaft 8 is disposed in parallel with the rear wheel drive output shaft 6.
[0013]
The rear wheel drive output shaft 6 and the transmission output shaft 2 are connected via an inner member 12 of the fluid coupling 11. The fluid coupling 11 distributes the power output from the transmission output shaft 2 to the front wheel drive output shaft 8 according to the rotational difference between the front and rear wheels, and is disposed in the internal space of the transfer case 4 on the front side. ing. In this space, for example, a 2-4 wheel switching mechanism, a low speed / high speed switching mechanism, and the like can be arranged, and can be shared with the part-time transfer case 4.
[0014]
As is well known, the fluid coupling 11 includes a sleeve-like inner member 12, a case 13 and a cam ring 14 which are outer members, and a space 15 filled with fluid is formed therebetween. The inner side of the inner member 12 is spline-fitted with the transmission output shaft 2 and the rear side is spline-fitted with the rear-wheel drive output shaft 6 so that both shafts 2 and 6 are directly connected. The rear end portion of the inner member 12 is inlayed (press-fitted) with the shaft portion 6 a of the rear wheel drive output shaft 6.
[0015]
Inside the space 15 are disposed a piston 16 that rotates integrally with the inner member 12, a spring 17 that presses the piston 16 against the cam ring 14, a valve 18 having an orifice 18a, and the like. Then, due to the difference in rotational speed between the inner member 12 on the input side and the cam ring 14 on the output side, the piston 16 is moved back and forth to flow the fluid, and the flow is restricted by the orifice 18a to increase the pressure and the piston 16 is moved back and forth. It produces resistance in operation and transmits torque. Thereby, the fluid coupling 11 transmits the power from the transmission output shaft 2 to the chain drive sprocket 20 according to the rotation difference.
[0016]
As shown in FIG. 2, the sprocket 20 is rotatably supported on the rear wheel drive output shaft 6 via an inner race 21. The tooth portion 20a of the sprocket 20 that meshes with the chain 22 is offset rearward in the axial direction. At the front portion of the sprocket 20, an outer spline 20b is formed which is spline-fitted with the inner spline 14b of the boss portion 14a protruding from the rear portion of the cam ring 14. Further, a press-fit fitting portion 20c that is inlayed (press-fitted) inside the tip end portion of the boss portion 14a is formed on the outer periphery of the intermediate portion of the sprocket 20.
[0017]
The outer periphery of the boss portion 14 a of the cam ring 14 is rotatably supported by the transfer case 4 via a bearing 23. A circumferential groove 14c is formed on the outer periphery of the tip end portion of the boss portion 14a, and a snap ring 24 for retaining the bearing 23 is fitted into the circumferential groove 14c. Note that a protrusion 20d that integrally positions the side surface and the outer peripheral surface of the snap ring 24 and prevents erroneous assembly is integrally formed at the front portion of the sprocket 20. Therefore, if the snap ring 24 is not properly fitted in the circumferential groove 14c of the boss portion 14a, the tip surface of the projection 20d pushes the snap ring 24 and is fitted into the circumferential groove 14c when the sprocket 20 is assembled. be able to. Further, after the snap ring 24 is fitted into the circumferential groove 14c, the inner circumferential surface of the protrusion 20d regulates the position of the outer circumferential surface of the snap ring 24, so that the snap ring 24 is reliably prevented from coming off from the circumferential groove 14c. it can.
[0018]
The chain 22 is wound around the sprocket 20 and a driven sprocket 30 provided integrally with the front wheel drive output shaft 8. Therefore, the differential torque transmitted to the sprocket 20 via the fluid coupling 11 is transmitted to the front wheel drive output shaft 8 via the chain 22.
[0019]
As described above, since the tooth portion 20a is offset in the axial direction, the drive-side sprocket 20 has an advantage that the axial dimension can be shortened, but on the other hand, a falling force acts on the sprocket 20 due to the chain load, and the chain 22 And the tooth surface wear and rotational resistance increase, and wear is likely to occur between the inner race 21 supporting the sprocket 20 in rotation. However, in the above embodiment, the press-fit fitting portion 20c of the sprocket 20 is inlayed (press-fit) inside the boss portion 14a of the cam ring 14, and the outer peripheral surface of the boss portion 14a of the cam ring 14 is supported by the bearing 23. The inclination of the sprocket 20 is prevented. Therefore, problems such as tooth surface wear and increased rotational resistance can be eliminated without providing a special bearing.
[0020]
In the above embodiment, since the inner spline 14b that is spline-fitted with the outer spline 20b of the sprocket 20 is provided inside the boss portion 14a of the cam ring 14, the spline portion can be disposed on the inner diameter side of the bearing 23. The coupling 11 and the sprocket 20 can be arranged at close positions with the bearing 23 therebetween. That is, the axial dimension can be shortened, and a compact transfer device can be realized.
[0021]
In the above transfer device, the intermediate portion of the output shaft 6 for driving the rear wheels is supported by the bearing 7, and the inner member 12 of the coupling 11 and the boss portion 14a of the cam ring 14 are inserted through the front side thereof. Supported by a bearing 23. That is, it will be supported at two places, front and rear, and stability will increase. Further, since the inner member 12 of the coupling 11 is not only spline-fitted with the rear wheel drive output shaft 6 but also is inlayed, the inner member 12 is integrated with the rear wheel drive output shaft 6. This eliminates the need to support the front end of the inner member 12 with a bearing. Therefore, the rear-wheel drive output shaft 6 can be pivotally supported by the minimum bearings 7 and 23, and the axial dimension and the number of parts can be further reduced.
[0022]
FIG. 3 shows a second embodiment of the present invention. The same parts as those in FIG.
In this embodiment, the outer peripheral surface of the boss portion 14a of the cam ring 14 of the fluid coupling 11 and the inner peripheral surface of the protrusion 20d for preventing misassembly of the snap ring of the sprocket 20 are inlayed (press-fitted). . That is, since the outer peripheral surface of the boss portion 14a is fitted with the bearing 23, it is processed with high accuracy. However, since this processed surface can be used as a press-fit surface with the sprocket 20 as it is, the number of processing steps can be reduced and the cost can be reduced. Reduction can be achieved.
Also in this embodiment, the inner spline 14b that is spline-fitted with the outer spline 20b of the sprocket 20 is provided inside the boss portion 14a of the cam ring 14, and the spline portion is disposed on the inner diameter side of the bearing 23.
[0023]
FIG. 4 shows a third embodiment of the present invention. The same parts as those in FIG.
In this embodiment, the boss portion 14 a of the cam ring 14 of the fluid coupling 11 is not inlayed (press-fitted) into the sprocket 20. In order to prevent the snap ring 24 fitted in the circumferential groove 14c on the outer peripheral surface of the boss portion 14a from falling off, a stopper 25 is fixed to the outer periphery of the tip end portion of the boss portion 14a by pressure bonding. In this case, the protrusion 20d for preventing the snap ring misassembly of the sprocket 20 is not provided.
Also in this embodiment, the inner spline 14b that is spline-fitted with the outer spline 20b of the sprocket 20 is provided inside the boss portion 14a of the cam ring 14, and the spline portion is disposed on the inner diameter side of the bearing 23.
[0024]
In the above embodiment, an example of fluid coupling using a piston and a cam ring as a coupling has been shown. However, other couplings such as a viscous coupling or a differential mechanism such as a center differential can be used. .
[0025]
【The invention's effect】
As is apparent from the above description, according to the invention of claim 1, the rear portion of the rear wheel drive output shaft is supported by the first bearing, and the front portion of the rear wheel drive output shaft is coupled via the coupling. Since it is supported by two bearings, the rear-wheel drive output shaft is supported at two points in the front-rear direction, and the rear-wheel drive output shaft can be stably supported with a minimum number of bearings.
[0026]
According to the invention of claim 2, the front part of the sprocket whose tooth part is offset to the rear side in the axial direction is press-fitted into the boss part provided on the outer member of the coupling, and this boss part is inserted through the bearing. Since it is rotatably supported by the transfer case, even if the sprocket teeth are offset on the rear wheel drive output shaft, the sprocket can be reliably prevented from tilting, and tooth surface wear and rotational resistance increase. The trouble can be solved. In addition, since no special bearing is required, an increase in the number of parts and an increase in the axial dimension can be prevented.
[Brief description of the drawings]
FIG. 1 is an overall sectional view of a first embodiment of a vehicle transfer apparatus according to the present invention.
FIG. 2 is a partially enlarged view of FIG.
FIG. 3 is a partial cross-sectional view of a second embodiment of a vehicle transfer apparatus according to the present invention.
FIG. 4 is a partial cross-sectional view of a third embodiment of a vehicle transfer apparatus according to the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Transmission 2 Transmission output shaft 3 Transfer device 4, 5 Transfer case 6 Rear wheel drive output shaft 7 First bearing 8 Front wheel drive output shaft 11 Fluid coupling 14a Boss portion 14a Inner spline 20 Sprocket 20b Outer spline 22 Chain 23 Second bearing

Claims (3)

The power output from the output shaft of the transmission is distributed to the rear wheel drive output shaft in series with the transmission output shaft and the front wheel drive output shaft in parallel with the rear wheel drive output shaft. In a vehicle transfer device provided with a coupling that transmits a differential torque between a drive output shaft and a front wheel drive output shaft,
A first bearing that pivotally supports the rear wheel drive output shaft with respect to the transfer case, and a second bearing that pivotally supports the outer member of the coupling with respect to the transfer case;
A chain drive sprocket that drives the front wheel drive output shaft is rotatably supported on the rear wheel drive output shaft,
The outer member of the coupling is connected to the chain drive sprocket so as to be integrally rotatable,
The front end of the rear wheel drive output shaft is connected to the rear end of the transmission output shaft via an inner member of the coupling,
The rear wheel drive output shaft and the coupling inner member are press-fitted and coupled. The power output from the output shaft of the transmission is distributed to the rear wheel drive output shaft in series with the transmission output shaft and the front wheel drive output shaft in parallel with the rear wheel drive output shaft. In a vehicle transfer device provided with a coupling that transmits a differential torque between a drive output shaft and a front wheel drive output shaft,
A boss portion that is rotatably supported by a transfer case via a bearing, and an inner spline portion is formed inside the boss portion at the rear portion of the outer member of the coupling,
A chain drive sprocket for driving the front wheel drive output shaft is rotatably supported on the rear wheel drive output shaft and the tooth portion is supported in an offset state on the rear side in the axial direction.
A vehicular transfer device, characterized in that a press-fitting fitting portion to be press-fitted with a coupling boss portion and an outer spline portion to be fitted with an inner spline portion of the coupling are formed at a front portion of the sprocket. The vehicle transfer device according to claim 2, wherein the press-fitting fitting portion of the sprocket is press-fitted into an outer peripheral surface of a boss portion of a coupling into which the bearing is press-fitted.

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