JPH0799197B2 - Power transmission device - Google Patents

Description

The present invention relates to an improvement of a power transmission device used in a vehicle or the like.

[Prior art]

As a conventional power transmission device attached to the rear of the transmission, for example, as shown in FIG. 8, power from an input shaft 101 is transmitted to a rear wheel drive shaft 107 via a first conduction path 103 and a second conduction path 104. A center differential 121 (differential device) is incorporated in the middle of the first conduction path 103 so as to allow a difference in rotation between the front wheel drive shaft 105 and the rear wheel drive shaft 107. There is. The center differential 121 includes a differential small gear shaft 123 integrated with the input shaft 101 and a differential small gear 12 mounted on the gear shaft 123.
5 and a differential large gear 127 that meshes with the small gear 125 and the rear wheel drive shaft 107 and is integrated, for example, by arranging the sleeve 129 disposed in front of the input shaft 101 to the right, the output gear 131
Of the output gear 131 through the intermediate gear 135 that meshes with the input gear 133, as shown by the thick solid line.
The low speed stage is obtained by being transmitted to the sleeve 129 and the input shaft 101, while being distributed and transmitted to the front wheel drive shaft 105 and the rear wheel drive shaft 107 via the center differential 121.

In general, the center diff 121 is capable of absorbing a rotation difference when the vehicle is turning, but when the front wheel slips in a wetland or the like, the power from the input shaft 101 is mainly used to idle the front wheel at a high speed. Since there is a problem that it is not transmitted to the rear wheel side, it is necessary to add a differential limiting mechanism to the center differential 121. Therefore, it is not desirable because it causes an increase in weight and an increase in size.

On the other hand, in the direct-coupling system that always drives four wheels without using the center differential mechanism, there is an advantage that the mechanism is simple and lightweight, but since the rotation difference between the front and rear wheel drive shafts is not absorbed, the front wheels are not used in low-speed cornering. The so-called tight corner braking phenomenon inevitably occurs because a twist occurs between the front and rear wheel drive shafts due to the different turning radii of the rear wheels.

In a four-wheel drive vehicle, this phenomenon occurs because the difference in the turning radii between the front and rear wheels causes a difference in rotational speed, that is, a twist between the front and rear wheel drive shafts. Since the engine output is small, the shaft twist causes an engine stall, which causes inconvenience. Further, there is a possibility that a sudden wear of the tire and a damage accident due to an abnormal torque of each portion of the transmission mechanism may occur.

[Object of the Invention]

Therefore, the present invention absorbs the rotation difference between the both drive shafts,
Further, the present invention provides a power transmission device for a vehicle, which has a function as a differential device with a differential limiting mechanism which does not cause a trouble of high speed idling at the time of slip, and which can be reduced in size and weight.

[Structure of Invention]

In order to achieve the above-mentioned object, in the present invention, the first power source for driving the front wheels (or the rear wheels) from the input side is used.
A first conduction path that is transmitted to the drive shaft, and a second path that drives the rear wheels (or the front wheels) by motive power branched and taken out from the path.
In a power transmission device for a direct-coupled four-wheel drive vehicle, which is provided with a second transmission path for transmitting to a drive shaft and is configured to always drive four wheels, an input member for receiving a rotation input from an input side and an input member On the other hand, an input side rotating member which is provided so as to be relatively movable in the axial direction and which is connected to the input member via a torque detection mechanism, and an input state rotating member which is provided between the input side rotating member and the first drive shaft. A friction clutch that is released during thrust and is engaged by axial movement of the input side rotating member at a predetermined thrust, and an axial direction of the input side rotating member that is provided between the input side rotating member and the second drive shaft. A structure is provided that includes a power transmission mechanism such as a spline that transmits power regardless of movement, and a fastening force adjusting member that adjusts the fastening force of the friction clutch according to the torque detection of the torque detection mechanism.

〔Example〕

An embodiment of the present invention will be described in detail below with reference to the drawings of FIGS.

The power from the input shaft (not shown) is transmitted to the gear 3 provided on the outer periphery of the case (input member) 1, the case 1 is rotated, and the meshing provided as the first conduction path in the case 1 is performed. The power from the input shaft is split and transmitted to the front wheel drive shaft 9 via the clutch type cam 5 and the friction clutch 7.

The dog clutch type cam 5 has a V-shaped protrusion arranged on the inner circumference of the case 1 as shown in a developed view in FIG. The V-shaped projections provided on the circumference of the end face of 11 are engaged to transmit the rotation.

The V-shaped projections also function as a torque detection mechanism for detecting the torque on the input shaft side, and the engaged V-shaped projections slide according to the increase / decrease in the detected torque value, resulting in thrust force. Also functions as an adjusting member for adjusting the fastening force of the friction clutch 7. Therefore, the mesh clutch type cam (also serving as the torque detection mechanism and the fastening force adjusting member) 5 releases the friction clutch 7 in the initial non-thrust state and engages it in a predetermined thrust state, and the slip state is set appropriately during that period. is there.

On the other hand, the rotation of the input side rotating member 11 is transmitted to the rear wheel drive shaft 17 via the dog clutch 13 provided as a mechanism for transmitting power to the second transmission path side. That is, the dog clutch 13 receives input from the case 1 at all times regardless of whether the input side rotating member 11 moves in the axial direction according to the power transmission from the cam 5 or not. It functions as a power transmission mechanism that transmits to the.

This dog clutch 13 is, as shown in the development view in FIG. 3,
A cup-shaped member 15 fixed to the end surface of the input side rotating member 11 on the opposite side of the dog clutch 5 and the shaft end of the rear wheel drive shaft 17.
Square columnar protrusions are arranged and provided on the circumference of the end face of, and are engaged with each other and locked.

Although there is clearance in the root part of this meshed tooth,
This is set to be equal to or more than the thrust amount corresponding to the operation of engaging and releasing the friction clutch so that the rotation can be transmitted without hindering the operation.

Also, backlash is provided on the back side of the contact surface of the meshed teeth. This also provides a clearance equal to or greater than the rotation angle of the mesh clutch type cam 5 between the engagement and disengagement of the friction clutch, so that the engagement of the friction clutch can be quickly released when a difference in rotation between the front and rear wheel drive shafts occurs. This is because no resistance is generated in the rotation of the clutch-type cam 5.

Input member (case) in the power transmission device having the above configuration
1, the front wheel drive shaft 9 is driven through the case 1, the dog clutch 5, the input side rotating member 11 and the friction clutch 7 during normal traveling, and the case 1, dog clutch 5, input clutch Side rotation member 11 and coupling clutch (transmission mechanism)
The rear wheel drive shaft 17 is driven via 13 to constantly drive the four wheels. From that state, if either of the front and rear wheels is in a slip state, the operation is as follows.

Even if the wheel load on the shaft 9 side is close to 0, one shaft 17
Since the side load does not change, the input side torque is transmitted to the shaft 17 side, the shaft 9 side also keeps the load light, and the friction clutch 7 remains lightly engaged and continues to rotate almost unchanged.

Further, even if the wheel load on the shaft 17 side becomes close to 0, the input side torque continues to be transmitted to the shaft 9 side without changing to the load on the shaft 9 side.
The side continues to rotate with almost no change.

In either case, the situation in which only the slip wheels rotate at high speed, which occurs when the differential device of the related art does not limit the differential, does not occur.

Furthermore, the rotational speed difference between the front and rear wheels that occurs at low speeds such as when entering a garage and when traveling on a sharp curve operates as follows.

In this case, since the vehicle is traveling at low speed and the input torque is small,
Since the thrust force of the dog clutch type cam 5 in the case 1 is small and the fastening force of the friction clutch 7 is weak, the clutch is in a situation where it is likely to slip. The shaft 17 side does not slip with the input side, but the other shaft 9 side is in a state where it easily slips, and the rotational speed difference between the front and rear wheels is absorbed here, affecting the input side. Does not reach.

This is a function capable of preventing the tight corner braking phenomenon, which is a difficulty that occurs when a direct-coupling type four-wheel drive vehicle that does not use the differential device runs at a low speed on a sharp curve.

The device of the present invention is also provided with a power transmission mechanism to the second transmission path side in the input side rotation member which is also the friction clutch engagement force adjusting member that also serves as the torque detection mechanism.

The embodiment in FIGS. 1 to 3 has been described above.
The present invention can be applied to other embodiments as follows.

FIG. 4 shows a spline connection between the input rotary member 11 of the friction clutch 7 and the cup-shaped member 15 fixed to the shaft end of the rear wheel drive shaft 11, and the input rotary member 11 is moved in the axial direction for engaging the friction clutch. It is possible to transmit rotation while allowing.

In FIG. 5, the same spline is used, but in this case, the spline of the input side clutch plate of the friction clutch 7 is extended and used, and the shaft end fixing member 15 on the other rear wheel drive shaft side is used.
This is also an example in which the number of parts is reduced by providing a spline on the outer circumference as a disk shape and using the end surface of this member as a support plate when the friction clutch is engaged.

Next, in FIG. 6, the input shaft 21 is connected to one of the rear wheel drive shafts 17 of the output shaft.
The output is taken out from the gear 23 on the outer circumference of the case 1 to the other front wheel drive shaft. In this case, the dog clutch 13 or the spline coupling portion in the above embodiment is omitted, but there is no functional change.

In FIG. 7, the input shaft and the output shaft are concentric, and one of the output shafts is taken out by the gear 25 from the hollow shaft on the input shaft side.

As for the axial relational arrangement, an appropriate arrangement may be selected from the arrangement of the conduction paths of the target four-wheel drive vehicle.

Further, in addition to the embodiment used as the center differential of the four-wheel drive vehicle described above, the power transmission device of the present invention can also be applied to the power transmission device for the left and right wheels in the front wheel or rear wheel drive vehicle. Acts as a differential device with motion limiting function.

〔The invention's effect〕

As described above, according to the power transmission device of the present invention, at the time of turning, it is possible to absorb the rotational difference between the front and rear drive shafts, and to eliminate the need for a differential device with a differential limiting mechanism having a complicated structure. , The differential function and the differential limiting function are obtained by the extremely simple structure that only the friction clutch whose engaging force is adjusted according to the input torque is provided, and either side is transmitted to the drive shaft of the front and rear wheels or the left and right wheels. Stable power transmission is achieved along the route. Therefore, the device can achieve higher performance, smaller size, and lighter weight.

[Brief description of drawings]

FIG. 1 is a longitudinal sectional view of an embodiment of a power transmission device of the present invention, FIGS. 2 and 3 are separate development schematic diagrams of the member 2 portion of FIG. 1, FIG. 4 and FIG. FIG. 6 is a vertical cross-sectional view of another example of the power transmission device according to the second embodiment. FIG. 6 and FIG. 7 are schematic diagrams of respective structures of still another embodiment 2 example, and FIG. 8 is an explanatory view of a conventional power transmission device. Description of main drawing symbols 1 ... Case (rotating member in front of friction clutch) 5 ... Matching clutch type cam (input side torque detection mechanism) 7 ... Frictional clutch (together with 5 mentioned above, serves as first conduction path) ) 9 ... Front wheel drive shaft (first drive shaft) 11 ... Input side rotating member (friction clutch fastening force adjusting member that has input torque detection part and power transmission part of second conduction path) 13 ... meshing Clutch (power transmission mechanism to the second conduction path side) 17 ... Rear wheel drive shaft (second drive shaft) 21 ... Input shaft (only shown in FIGS. 6 and 7)

Claims (1)

[Claims] 1. A first transmission path for transmitting power from an input side to a first drive shaft for driving front wheels (or rear wheels), and power extracted by branching from the first rear wheel (or front wheels). In a power transmission device for a direct-coupling type four-wheel drive vehicle, which is provided with a second transmission path for transmitting to a second drive shaft for driving), the rotary input from the input side is always provided. An input member that receives the input member; an input-side rotating member that is axially movable relative to the input member and that is connected to the input member through a torque detection mechanism; and the input-side rotating member and the first drive shaft. It is provided between the input side rotation member and the second drive shaft, and a friction clutch which is provided between the input side rotation member and the friction clutch which is released during non-thrust in the initial state and is engaged by axial movement of the input side rotation member at a predetermined thrust. Related to the axial movement of the input side rotating member Ku and a power transmission mechanism of a spline for performing power transmission, power transmission apparatus characterized by comprising a fastening force adjusting member for adjusting the engagement force of the friction clutch according to the torque detection of the torque detection mechanism.