JP2001221262A - Coupling and differential device using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To control a toque transmission characteristic of a differential rotational frequency sensing type in accordance with rotational speed while providing a simple structured, small, and lightweight constitution. SOLUTION: This device is provided with a clutch 7 arranged between torque transmission members 3 and 5, a cam mechanism 11 arranged between the members 3 and 5 via a differential rotational frequency sensing type coupling device 9 and pressing the clutch 7 with cam thrust force in accordance with differential rotation frequency, and a torque transmission characteristic control mechanism 17 controlling the torque transmission characteristic in accordance with the rotational speed by moving a position of a point of application of the can mechanism 11 in a diametric direction in accordance with the rotational speed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coupling and a differential using the same.

2. Description of the Related Art As a conventional differential device using a coupling, Japanese Utility Model Laid-Open No. 5-12767 discloses a driving force transmission device 201 as shown in FIG.

[0002] This driving force transmission device 201 is arranged in a rear wheel side power transmission system of a four-wheel drive vehicle. This vehicle is a front wheel drive base and has a driving force transmission device 201 as described below.
Transmits driving force to the rear wheels when differential rotation occurs between the front and rear wheels.

[0003] The driving force transmitting device 201 includes an outer case 203 connected to a propeller shaft on the engine side, an end cover 205 fixed to the outer case 203,
Inner shaft 207, outer case 203 and inner shaft 2 connected to the propeller shaft on the rear wheel side
07, a multi-plate clutch 209, a pressing force generating unit 211 for pressing the multi-plate clutch 209, a pressing force control unit 213 for controlling the pressing force, and the controller 21.
5, a control circuit 217 and the like.

[0004] The pressing force generating means 211 includes a multi-plate clutch 2.
09, a fluid chamber 221 formed between the piston 219 and the end cover 205, a rotor 223 connected to the inner shaft 207 in the fluid chamber 221, and a silicon oil (high) filled in the fluid chamber 221. (Viscous fluid).

[0005] The rotor 223 is provided with a vane 225 for stirring a highly viscous fluid.

Under conditions in which differential rotation occurs between the front and rear wheels, such as when the vehicle starts or accelerates, when traveling on a rough road, or when the wheels spin, the rotor 223 rotates and the vane 225 rotates. Agitates the highly viscous fluid, and pressure is generated in the fluid chamber 221. The piston 219 is moved by this pressure, and the multiple disc clutch 209 is pressed and fastened.

[0007] When the multi-plate clutch 209 is engaged, the driving force of the engine is transmitted to the rear wheel side, and the starting performance, acceleration performance, running performance on rough roads, escape from the stack, and the like are improved.

The pressing force of the multi-plate clutch 209 (the fluid chamber 22
1) increases as the differential rotation speed increases, a large driving force is transmitted to the rear wheel side, and the above-described respective effects are enhanced.

When no differential rotation occurs between the front and rear wheels,
Since the multi-plate clutch 209 is not engaged, the rear wheel side rotates in a co-rotating state, thereby preventing a reduction in engine fuel efficiency.

Further, the pressing force control means 213 is provided in the fluid chamber 2.
It comprises a plunger 227, a compression spring 229, a solenoid 231 and the like arranged in contact with 21. The solenoid 231 on the rotating side is connected to the vehicle-mounted battery from the control circuit 217 on the stationary side via a slip ring.

A controller 215 sends an exciting current to a solenoid 231 via a control circuit 217,
27 is sucked to the right in FIG. When the plunger 227 is sucked, the volume of the fluid chamber 221 increases, the pressure generated by the rotation of the rotor 223 decreases, and the driving force transmitted from the driving force transmission device 201 (multi-plate clutch 209) to the rear wheel side increases. Become smaller.

When the position of the plunger 227 is changed by adjusting the exciting current of the solenoid 231, the driving force sent to the rear wheels changes.

When the excitation of the solenoid 231 is stopped, the plunger 227 returns to the original position by the compression spring 229, and the volume of the fluid chamber 221 is minimized, so that the rotor 2
The pressure due to the rotation of 23 increases, and the driving force sent to the rear wheel side by the differential rotation becomes maximum.

As described above, the transmission torque characteristic of the driving force transmission device 201 can be controlled by the pressing force control means 213. If the transmission torque is increased during low-speed running of the vehicle, the starting performance and Acceleration, rough road running, and escape from the stack are greatly improved.

[0015] Further, if the transmission torque is reduced during high-speed running, fuel efficiency is further improved.

[0016]

However, the conventional driving force transmission device 201 requires the pressing force control means 213 to control the transmission torque characteristics according to the vehicle speed.
In order to control this, wiring, a controller 215, a control circuit 217, and the like are used.

As described above, the driving force transmission device 201 uses an electric control system and has a complicated structure and a large number of parts, so that it is costly, large and heavy, and there is a limitation on the vehicle mountability. There's a problem.

Therefore, the present invention can control the torque transmission characteristics of the differential-rotation-speed-sensitive driving force transmission device in accordance with the rotation speed (vehicle speed) while simplifying the structure and reducing the size and weight. The purpose is to provide a coupling.

[0019]

According to a first aspect of the present invention, a coupling is provided between a pair of torque transmitting members via a clutch disposed between a pair of torque transmitting members and a differential rotation speed sensitive coupling device. And a cam mechanism for pressing and connecting the clutch with a cam thrust force corresponding to the differential rotation speed between the two torque transmitting members received via the connecting device, and the action point position of the cam mechanism according to the rotation speed. It is characterized in that a torque transmission characteristic control mechanism for controlling the torque transmission characteristic in accordance with the rotational speed by changing in the radial direction is provided.

Therefore, when a differential rotation occurs between the two torque transmitting members, the cam mechanism operates by the differential torque transmitted through the differential-speed-sensitive coupling device, and receives the cam thrust force to receive the clutch. Is pressed, the coupling is connected, and the torque is transmitted from one torque transmitting member to the other torque transmitting member.

Due to the characteristics of the differential speed-sensitive coupling device, the differential torque transmitted to the cam mechanism increases as the differential speed between the two torque transmitting members increases. That is, the torque transmitted via the coupling increases as the differential rotation speed increases, and decreases as the differential rotation speed decreases.

When the two torque transmitting members stop the differential rotation, the differential speed-sensitive coupling device also stops operating, the cam thrust force of the cam mechanism disappears, the clutch is released, and the coupling of the coupling is disconnected. It is released.

The coupling obtains a torque transmission characteristic which becomes larger as the differential rotation speed increases, by the differential rotation speed sensitive type coupling device.

On the other hand, when the same differential torque is received, when the point of action of the cam mechanism is moved radially outward,
Since the point of action of the cam mechanism is separated from the axis, the load applied to the cam groove is reduced. Conversely, if the point of action is moved inward in the radial direction, the load applied to the cam groove increases. Therefore,
The cam thrust force (coupling transmission torque) generated in the cam mechanism becomes smaller as the point of action is moved radially outward, and becomes larger as the point of action is moved radially inward.

The coupling of the present invention is provided with a torque transmission characteristic control mechanism for radially moving the position of the operation point of the cam mechanism in accordance with the rotational speed. The transmission torque is controlled in accordance with the rotation speed so that the transmission torque is moved outward to reduce the coupling torque, and when the rotation speed decreases, the point of action is moved radially inward to increase the coupling transmission torque. be able to.

The coupling of the present invention is applied to a rear-wheel-side power transmission system from a transfer to a rear differential (a differential device for distributing the driving force of the engine to the right and left rear wheels) in, for example, a front-wheel drive four-wheel drive vehicle. When it is arranged, the driving force is transmitted to the rear wheel side via the coupling in the state where differential rotation occurs between the front and rear wheels such as when starting, accelerating, traveling on rough roads, stacking, etc. In addition, the acceleration, the ability to drive on a rough road, and the like are improved, or the player can escape from the stack.

The torque transmitted to the rear wheels via the coupling increases as the differential rotation speed increases, and the effect of improving these increases.

In a state where no differential rotation occurs between the front and rear wheels, the coupling is released and the rear wheel side is brought into a rotating state, and the vehicle is substantially in the front wheel drive state, and the engine is not driven. Fuel efficiency is improved.

However, the torque transmission characteristics described above using only the differential-speed-sensitive coupling device and the cam mechanism are characteristics such that a large transmission torque can be obtained in a low-speed running range of the vehicle, for example, due to escape from the stack. In the high-speed running range, unnecessary driving force is transmitted to the rear wheels, which affects the fuel efficiency of the engine. However, if the transmission torque in the high-speed running range is set to be small, sufficient torque cannot be transmitted to the rear wheels in the low-speed running range, making it difficult to escape from the stack.

Therefore, if the coupling of the present invention is configured such that the transmission torque of the coupling becomes smaller as the vehicle speed becomes higher by the transmission torque control function of the torque transmission characteristic control mechanism, the coupling can be used when starting, accelerating, and rough road. The driving force of the rear wheels increases in low-speed driving areas such as when driving and stacking, and the effects of improving startability, acceleration, running on rough roads, and getting out of the stack are further enhanced, and the high-speed driving area In this case, the driving force of the rear wheels is reduced, and the fuel efficiency can be further improved.

Also, at the time of medium speed running, the differential rotation between the front and rear wheels is appropriately allowed by the coupling, so that the turning performance of the vehicle is improved, and the maneuverability and stability during the turning running are improved. I do.

Further, according to the transmission torque control function of the torque transmission characteristic control mechanism, the transmission torque of the coupling (rotation restraining force between the front and rear wheels) is reduced when the vehicle is running at a low speed just before stopping, such as during braking. It is possible to set A.D. during braking. B. S (antilock brake system) is prevented from interfering. B.
The normal operation of S is preserved.

As described above, the coupling of the present invention that moves the action point position of the cam mechanism in the radial direction in accordance with the rotation speed includes a pressing force control means 213, a slip ring, a controller 215, a control circuit 217, a battery, and the like. Unlike the conventional example that controls the transmission torque characteristics according to the vehicle speed by using an electrical control system, the structure is simple, the number of parts is small, the reliability is high, and the cost is low. In addition, it is small and lightweight, and can be mounted easily.

Further, the coupling of the present invention can control the torque transmission characteristic of the differential rotation responsive type according to the rotation speed (vehicle speed) of the entire apparatus while having the above advantages, and as a result, In addition, the traveling performance, maneuverability and stability of the vehicle are greatly improved.

According to a second aspect of the present invention, there is provided the coupling according to the first aspect, wherein the cam mechanism comprises a cam groove provided in a radial direction and a rolling element movable on the cam groove. The transmission characteristic control mechanism is a biasing means for biasing the rolling element radially inward against the centrifugal force of the rolling element, and the same operation and effect as the configuration of claim 1 can be obtained.

In this configuration, the centrifugal force of the rolling element and the urging force of the urging means are opposed to each other, and when the rotation speed (vehicle speed) increases, the rolling element moves radially outward to transmit the transmission torque of the coupling. When the rotation speed (vehicle speed) decreases, the rolling elements move radially inward, and the transmission torque of the coupling increases.

As described above, the coupling having the structure in which the urging force of the urging means is opposed to the centrifugal force of the rolling element has a very simple structure, has a small number of parts, is small in size and light in weight, and has improved vehicle mountability. Can be.

Further, the centrifugal force of the rolling element and the deflection of the urging means opposed thereto change continuously according to the change of the rotation speed (vehicle speed). In accordance with a change in the speed (vehicle speed), the control can be performed continuously, not stepwise, and the traveling performance, maneuverability, and stability of the vehicle are greatly improved.

Further, if the cam angle of the cam groove is changed depending on the rotational direction of the coupling (during forward running and backward running of the vehicle), for example, the cam thrust force of the cam surface contacting during reverse running is reduced. Engine braking and A. B. Interference with S (anti-lock brake system) can be prevented.

According to a third aspect of the present invention, there is provided the coupling according to the second aspect, wherein an angle of the cam groove is changed depending on a radial position, and an operation equivalent to that of the second aspect is provided.・ Effect can be obtained.

Further, in this configuration in which the angle of the cam groove is changed according to the radial position, the transmission torque can be finely changed depending on the rotational speed (vehicle speed), and the torque transmission characteristics of the coupling can be adjusted arbitrarily. Can be.

With this adjusting function, a desired torque transmission characteristic can be obtained at a specific vehicle speed. For example, in the case of the vehicle according to the first aspect, the coupling force of the coupling can be increased to some extent when the vehicle runs at a medium to high speed. For example, the stability at the time of turning is improved.

Also, the cam angle is set so that the transmission torque of the coupling (rotation restraining force between the front and rear wheels) at the innermost side in the radial direction that comes into contact with the rolling element during low-speed running just before stopping, such as during braking, is small. Alternatively, if the cam angle of the cam groove contacting during braking is reduced, A. B. Interference with S is prevented.

As described above, it is possible to precisely adjust the torque transmission characteristic of the coupling, and it is possible to widely support different types of vehicles.

According to a fourth aspect of the present invention, there is provided a differential device for driving a case-like torque transmitting member which is rotated by a driving force of an engine, and rotating the case-like torque transmitting member via a pair of shaft-like torque transmitting members. A differential mechanism for distributing to the wheel side, and a coupling according to any one of claims 1 to 3, wherein the differential of the differential mechanism is limited by a clutch disposed between the torque transmitting members. And

When differential rotation occurs in the differential mechanism, for example,
The differential torque between the case-shaped torque transmitting member and the shaft-shaped torque transmitting member is applied to the cam mechanism via the differential speed-sensitive coupling device, and the clutch is coupled by the generated cam thrust force, and the frictional resistance (difference) of the clutch is increased. The motion limiting force) limits the differential of the differential mechanism.

According to the above-described functions of the couplings according to the first to third aspects, the differential limiting characteristic of the differential rotation responsive type can be controlled according to the rotation speed (vehicle speed).
A. Vehicle traveling, maneuverability, stability, acceleration, stack escape, B. The function of preventing interference with S is greatly improved.

In addition, the differential device according to the fourth aspect uses the coupling according to the first to third aspects, so that the structure is simple, the number of parts is small, the reliability is high, and the cost is low. It is small, lightweight, and can be mounted easily.

[0049]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A coupling 1 (first embodiment of the present invention) will be described with reference to FIGS.

This coupling 1 has the features of the first and second aspects. FIG. 1 shows the coupling 1, and FIG. 8 shows a power system of a four-wheel drive vehicle using the coupling 1. The left and right directions are the left and right directions of the vehicle, and the right side in FIG. 1 corresponds to the front of the vehicle.

As shown in FIG. 8, this power system includes a horizontally disposed engine 101, a transmission 103, a transfer 105, a front differential 107 (a differential device for distributing the driving force of the engine 101 to the left and right front wheels), a front axle 109, 111, left and right front wheels 113 and 115, rear wheel side propeller shaft 117, coupling 1, rear differential 119, rear axles 121 and 123, left and right rear wheels 125,
127 and the like.

As described above, the coupling 1 is arranged in the power transmission system on the rear wheel side.
5, 127 is controlled.

The driving force of the engine 101 is transmitted from the output gear 129 of the transmission 103 to the differential casing 133 of the front differential 107 via the ring gear 131, and from the front differential 107 via the front axles 109 and 111 to the left and right front wheels 113. , 115 and transmitted to the coupling 1 via the differential casing 133, the transfer 105, and the propeller shaft 117.

When the coupling 1 is connected, the driving force of the engine 101 is transmitted from the rear differential 119 to the rear axle 121,
Distributed to the left and right rear wheels 125, 127 via 123,
The vehicle enters the four-wheel drive state.

When the connection of the coupling 1 is released, the rear wheels below the rear differential 119 are disconnected, and the vehicle enters a two-wheel drive state.

As shown in FIG. 8, the rear differential 119 is accommodated in a differential carrier 135. This differential carrier 135
Is constructed by connecting a casing body 137 and a front casing 139 with bolts 141.

The coupling 1 is housed on the front casing 139 side.

As shown in FIG. 1, the coupling 1 includes a rotating case 3 (a torque transmitting member on one side), a hollow inner shaft 5 (a torque transmitting member on the other side), and a multi-plate clutch 7 (clutch). , Differential speed-sensitive coupling device 9, ball cam 1
1 (cam mechanism), a cam member 13, a pressure plate 15, a coil spring 17 (torque transmission characteristic control mechanism: urging means), and the like.

The rotating case 3 comprises the cylindrical member 19 and the connecting shaft 2
1 and an end cover 23. The connecting shaft 21 is formed with a flange 25.
Is welded to the front end of the cylindrical member 19 at the flange portion 25. The end cover 23 is disposed on the rear end side of the cylindrical member 19, and is positioned by a snap ring 27 attached to the cylindrical member 19.

The inner shaft 5 penetrates the cylindrical member 19 of the rotating case 3. The front end of the inner shaft 5 is supported on the flange 25 by a ball bearing 29, and the rear end is supported on the cylindrical member 19 via the end cover 23.

An O-ring 31 is arranged between the end cover 23 and the cylindrical member 19, and an oil seal 33 is arranged between the end cover 23 and the inner shaft 5. Thus, a sealed space 35 is formed between the rotating case 3 and the inner shaft 5. Also, the inner shaft 5
Is provided with a capacity increasing space 37 which communicates with the space 35 to increase the capacity thereof.

A predetermined amount of oil is filled from an oil supply flow path 39 provided in the flange
5 and the inside of the capacity increasing space 37 are filled with the filled oil and air. After filling with oil,
9 is sealed by press-fitting a closed ball 41.

As shown in FIG. 8, the connecting shaft 21 of the rotating case 3
Protrudes forward from the front cover-139 of the differential carrier 135, and is connected to the companion flange 143 by a spline portion 43.

The companion flange 143 is connected to the flange 147 on the joint 145 side, and
The motor 3 is connected to the propeller shaft 117 side.

A drive pinion shaft 149 is connected to the spline portion 45 of the inner shaft 5. A drive pinion gear 151 is formed on the drive pinion shaft 149. The drive pinion gear 151 meshes with a ring gear 153 on the rear differential 119 side to drive the rear differential 119 to rotate.

The differential carrier 135 is filled with lubricating oil for the rear differential 119, and lubricates the meshing portions between the drive pinion gear 151 and the ring gear 153, the supporting bearings thereof, and the sliding portions of each member.

The multi-plate clutch 7 includes a plurality of outer plates 47 and inner plates 4 alternately arranged in the axial direction.
9 and each outer plate 47 has a rotating case 3
The inner plate 49 is movably connected to a meshing portion 51 provided on the inner periphery of the cylindrical member 19, and each inner plate 49 is movably connected to a meshing portion 53 provided on the outer periphery of the inner shaft 5.

The differential rotation speed sensitive type coupling device 9 is arranged alternately inside the fluid chamber 57 and the fluid chamber 57 provided between the boss 55 provided on the cam member 13 and the cylindrical member 19. It is composed of a plurality of outer plates and inner plates. A high-viscosity fluid such as silicone oil is sealed in the fluid chamber 57, each outer plate is connected to the cylindrical member 19 side, and the inner plate is connected to the boss 55 side.

When a differential rotation occurs between the rotating case 3 (the cylindrical member 19) and the cam member 13 (the boss 55), the outer plate and the inner plate agitate the highly viscous fluid, and the shearing resistance causes the rotating case 3 to rotate. 3 and cam member 13
The relative rotation therebetween is restricted, and a differential torque corresponding to the rotation restricting force is transmitted between the rotating case 3 and the cam member 13.

As shown in FIGS. 2 and 3, the ball cam 11 includes a cam groove 59 provided in the cam member 13 and a cam groove 61 provided in the pressure plate 15 as shown in FIG. The ball 63 (rolling element) is disposed between the balls.

The cam grooves 59 and 61 are provided at a plurality of positions at equal intervals in the circumferential direction, and each of the cam grooves 59 and 61 is formed in a radial direction (radially). The respective cam angles are the same in both rotation directions (when the vehicle is traveling forward and when traveling backward).

The coil spring 17 is arranged in a compressed state between the convex portion 65 formed on the outer peripheral side of the cam member 13 and the ball 63, and moves the ball 63 radially inward against the centrifugal force. It is energizing.

The pressure plate 15 is movably connected to the outer periphery of the inner shaft 5 by a spline portion 67, and presses the multi-plate clutch 7 by receiving the cam thrust force of the ball cam 11. A snap ring 69 that receives a cam reaction force of the ball cam 11 via a cam member 13 is attached to the outer periphery of the rear end portion of the inner shaft 5.

Each inner plate 49 of the multi-plate clutch 7
Is provided with an oil flow hole 71, which reduces the resistance of the oil received by the inner plate 49 when the multi-plate clutch 7 is pressed by the pressure plate 15 and when the pressing is released. Plate clutch 7
To improve the opening and closing response. Further, the oil is easily moved between the inner plates 49 by the flow holes 71, and the lubricity and the cooling property between the inner plate 49 and the outer plate 47 are improved.

Plates 73, 73 are arranged between the multi-plate clutch 7 and the flange portion 25. By changing the thickness of these plates, the gap between the inner plate 49 and the outer plate 47 is adjusted to an optimum value. ing.

As described above, the differential speed-sensitive coupling device 9 and the ball cam 11 are arranged in series between the rotating case 3 and the inner shaft 5, and between them (the front wheel 1).
13, 115 and the rear wheels 125, 127), the differential torque causes the ball cam 11 to operate via the differential speed-sensitive coupling device 9, and the generated cam thrust force is applied to the pressure. The multi-plate clutch 7 is pressed via the plate 15 to connect the coupling 1.

Therefore, when a differential rotation occurs between the front and rear wheels when the vehicle starts, accelerates, is traveling on a rough road, or is stuck, the coupling 1 is connected to drive the engine 101 to the rear wheels 125 and 127. Power is sent to improve starting performance, acceleration performance, running ability on rough roads, etc., and it is possible to escape from the stack.

The differential torque transmitted to the ball cam 11 increases as the differential rotation speed between the front and rear wheels increases due to the characteristics of the differential rotation speed sensitive type coupling device 9. The torque transmitted to the wheels 125 and 127 increases as the differential rotation speed increases, and the effects of improving starting performance, acceleration, running on bad roads, and exiting the stack increase.

When the differential rotation does not occur between the front and rear wheels, the operation of the differential rotation speed sensitive coupling device 9 also stops, the cam thrust force of the ball cam 11 disappears, and the multi-plate clutch 7 is released. , The coupling of the coupling 1 is released.

Thus, the rear wheel 12 below the coupling 1
The 5,127 side is brought into a rotating state, and the vehicle is substantially in the front wheel drive state, so that the fuel efficiency of the engine 101 is improved.

When the coupling 1 rotates, the ball 63 of the ball cam 11 receives centrifugal force and receives a coil spring 1
7 to bend and move radially outward. The moving position becomes more outward as the rotation speed of the coupling 1 increases.

FIG. 2 shows the position of the ball 63 when the vehicle is traveling at a low speed. The ball 63 is moved radially inward by the urging force of the coil spring 17. FIG. 3 shows the position of the ball 63 when the vehicle is traveling at a high speed, and the ball 63 is moving radially outward under a large centrifugal force.

When the same differential torque is received, when the ball 63 of the ball cam 11 is moved to the outside in the radial direction, the load applied to the cam surfaces 59 and 61 is reduced, and the ball 63 is moved to the inside in the radial direction. Then, the cam surfaces 59, 6
The load applied to 1 becomes large. Therefore, the ball cam 11
The cam thrust force (the transmission torque of the coupling 1) generated when the ball 63 moves outward in the radial direction (the point of application) decreases when the ball 63 moves outward in the radial direction, and increases when the ball 63 moves inward in the radial direction.

Thus, the transmission torque of the coupling 1 increases during low-speed running in FIG. 2 and decreases during high-speed running in FIG.

FIG. 4 shows the differential rotation speed (△
The graph of N) and the transmission torque (T) show that it changes with the vehicle speed.

The graphs 301, 303, 305, 307,
309 corresponds to the high-speed vehicle speed in this order. Due to the above-described characteristics of the differential speed-sensitive coupling device 9, the transmission torque (T) increases as the differential speed (△ N) increases in each graph.

Further, since the torque transmission characteristic changes as described above due to the movement of the ball 63 accompanying the change in the vehicle speed, the transmission torque of the coupling 1 increases as the vehicle speed decreases and decreases as the vehicle speed increases.

FIG. 5 is a graph showing changes in the rotational speed of the coupling: vehicle speed (S) and transmission torque (T).

The graph 311 shows the change in the vehicle speed (S) and the transmission torque (T) of the coupling 1, and as described above, the transmission torque (T) increases as the vehicle speed (S) decreases. , Smaller at higher speeds.

A graph 313 shows a torque transmission characteristic of a coupling configured to be connected to the differential rotation speed sensitive type connecting device only by the cam mechanism.

Since this does not correspond to the change in the vehicle speed (S), if the characteristic is set such that a large transmission torque is obtained in the low-speed running range of the vehicle, for example, the escape from the stack, in the high-speed running range, Unnecessary driving force is transmitted to the rear wheels 125 and 127, and the fuel efficiency of the engine 101 is reduced. However, if the transmission torque in the high-speed traveling region is set to be small, sufficient torque cannot be transmitted to the rear wheels 125 and 127 in the low-speed traveling region, and escape from the stack becomes difficult. As described above, it is difficult to obtain necessary functions in all speed ranges.

However, in the coupling 1, a large driving force is transmitted to the rear wheels 125 and 127 as described above in a low-speed traveling range such as when starting, accelerating, traveling on a rough road, or stuck. From the start, a sufficient improvement effect can be obtained in starting performance, acceleration, running on rough roads, escape of the stack, etc.
In the high-speed running range, the driving force is not substantially transmitted to the rear wheels 125 and 127, and a decrease in the fuel efficiency of the engine 101 is prevented.

Further, the transmission torque of the coupling 1 (rotation restraining force between the front and rear wheels) is reduced during low-speed running. B. S (antilock brake system) is prevented from interfering. B. The normal operation of S is preserved.

Further, when the vehicle is running at medium speed, the differential rotation between the front and rear wheels is appropriately allowed by the coupling 1, so that the turning performance of the vehicle is improved, and the maneuverability and stability during the running are improved. I do.

The oil sealed in the space 35 and the capacity increasing space 37 circulates inside by the centrifugal force of the coupling 1, and the ball 63 of the ball cam 11 and the cam surfaces 59 and 5.
9, 61, 61, the ball bearing 29, the sliding surface of the outer plate 47 and the inner plate 49 of the multi-plate clutch 7, the spline portion 67, and the like are lubricated and cooled.

In particular, the ball 63 and the cam surfaces 59, 59, 6
By fully lubricating the contact portion with 1,61,
The radial movement of the ball 63 is performed smoothly, and the function of controlling the torque transmission characteristic is maintained normally.

Thus, the coupling 1 is configured.

As described above, the coupling 1 is configured so that the position (point of action) of the ball 63 is moved by the centrifugal force, so that the driving force of the engine 101 transmitted to the rear wheels 125 and 127 and The rotation restraining force between the front and rear wheels can be controlled according to the vehicle speed.

The torque transmission characteristic control mechanism of the coupling 1 in which the urging force of the coil spring 17 is opposed to the centrifugal force of the ball 63 is provided with a pressing force control means 213 for controlling the transmission torque characteristic according to the vehicle speed. ring,
Unlike a conventional example requiring a controller 215, a control circuit 217, a battery, and the like, an electrical control system is not used and the structure is extremely simple, so that the reliability is high.

Further, since the number of components is small, the size and weight can be reduced, and the mountability can be improved.

Since the centrifugal force of the ball 63 and the deflection of the coil spring 17 opposed thereto change continuously according to the change of the rotation speed (vehicle speed), the coupling 1 changes the transmission torque to the change of the vehicle speed. Accordingly, not step by step
Can be controlled continuously.

Accordingly, it is possible to greatly improve the running performance, the maneuverability, the stability, and the like of the vehicle.

The cam angle of the ball cam 11 can be changed depending on the rotation direction (during forward running and backward running of the vehicle). For example, if the cam thrust force is reduced on the cam surface that comes into contact during backward running, braking can be performed. Sometimes engine braking and A. B. Interference with S (anti-lock brake system) can be prevented.

Note that the coupling 1 corresponds to the arrow 17 in FIG.
As shown in FIG. 1, it may be arranged between the transfer 105 and the propeller shaft 117.

In this case, as in the case of the above-described embodiment, which is disposed between the propeller shaft 117 and the rear differential 119, the coupling 1 transmits the driving force of the engine 101 transmitted to the rear wheels 125 and 127, The rotation restraining force between the front and rear wheels is controlled according to both the differential rotation speed and the vehicle speed.

Further, the coupling 1 is indicated by arrows 173, 1
As indicated by reference numeral 75, it may be disposed between the front differential 107 and either of the left and right front wheels 113, 115.
As shown by 77 and 179, it may be arranged between the rear differential 119 and one of the left and right rear wheels 125 and 127.

In any case, while no differential rotation occurs in the front differential 107 and the rear differential 119, the connection of the coupling 1 is substantially released, and the vehicle is driven by two wheels.

When the differential rotation occurs, the coupling 1 is connected, and the driving force according to the differential rotation speed and the vehicle speed is transmitted to the front and rear wheels, so that the vehicle enters the four-wheel drive state, and the starting and acceleration characteristics are increased. The ability to drive on rough roads and escape from the stack are improved.

Note that the coupling 1 is indicated by arrows 177 and 17
9, the transfer 105 is provided with a clutch (2-4 switching mechanism) for intermittent driving force, and this is interlocked and interlocked with the coupling 1 so that the coupling 1 puts the vehicle in a two-wheel drive state. When it becomes, it becomes possible to keep the propeller shaft 117 completely stationary,
Noise, vibration, wear and the like are greatly reduced, and the fuel efficiency of the engine 101 is improved.

Further, as shown by an arrow 181, the coupling 1 may be arranged in combination with a gear mechanism in the transfer 105. In this case, the coupling 1 is arranged between the propeller shaft 117 and the rear differential 119. A function equivalent to that of the embodiment is obtained.

The coupling 1 is indicated by arrows 171, 18
1, the hub clutches 183, 185 are located between the rear axles 121, 123 and the rear wheels 125, 127.
Are disengaged while the coupling of the coupling 1 is disconnected, the power transmission system from the coupling 1 to the rear wheels 125 and 127
The rotation of the engine 101 and the rotation by the rear wheels 125 and 127 are shut off, the rotation stops, noise, vibration, wear, and the like are greatly reduced, and the fuel efficiency of the engine 101 is improved.

Next, a coupling according to a second embodiment of the present invention will be described with reference to FIGS.

This coupling has the features of the first, second and third aspects and is arranged at the same position as the coupling 1 of the four-wheel drive vehicle shown in FIG. In the following, members having the same functions as those of the coupling 1 are given the same reference numerals and quoted, and redundant description thereof will be omitted.

FIGS. 6 and 7 show a ball cam (cam mechanism) used for the coupling of the second embodiment.

This ball cam has a configuration in which a ball 63 is arranged between the cam member 13 and the pressure plate 15 in the same manner as the ball cam 11 of the coupling 1. It moves in the radial direction according to the vehicle speed by the power.

In the coupling of the second embodiment, the cam angle (the inclination angle of the cam groove) in the cam groove of the cam member 13 and the pressure plate 15 is changed depending on the radial position.

FIGS. 6 and 7 show cam angles on the cam member 13 side. FIG. 6 shows a radially inner state where the ball 63 contacts when the vehicle runs at a low speed, and FIG. 7 shows a radially outer state where the ball 63 contacts when the vehicle runs at a high speed.

On the radially inner side, as shown in FIG.
The cam angle α1 of 1,81 is small. On the other hand, on the outer side in the radial direction, as shown in FIG.
Is big.

The cam surface on the pressure plate 15 side also
It is configured similarly.

Here, the ball cam 11 of the coupling 1
From the cam surfaces 59 and 61, the cam angle α of the cam surfaces 81 and 81
1 and the cam angle α2 of the cam surfaces 83, 83 are increased, the transmission torque (T) during low-speed running is further increased, and the transmission torque (T) during high-speed running, as shown by the graph 315 in FIG. T) is further reduced. Also, due to this characteristic, the transmission torque (T) of the graph 301 of FIG. 4 is further increased as shown by the graph 317, and the transmission torque (T) of the graph 309 is further reduced as shown by the graph 319.

As described above, in the coupling according to the second embodiment, the driving force transmitted to the rear wheels 125 and 127 at the time of low-speed running is further increased, so that the vehicle can be started, accelerated, run on a rough road, and escape from the stack. As a result, the driving force of the rear wheels 125 and 127 is reduced during high-speed running, and the fuel efficiency of the engine 101 is further improved.

Here, the cam angle is set to be radially inward,
Although the two outer portions in the radial direction are illustrated and described, the cam angle is not limited to being changed in two stages, and the cam angle may be changed in a plurality of stages depending on the position, or may be changed continuously. Good. Further, the cam angle may be changed depending on the rotation direction.

In this way, the torque transmission characteristics of the coupling can be adjusted more precisely, and it is possible to widely support different types of vehicles.

In the present invention, the differential rotation speed sensitive type connecting device is not limited to the one using the shear resistance of the highly viscous fluid used in each embodiment.

[0125] For example, a differential rotation speed-sensitive coupling device that rotates a blade in a fluid chamber by differential rotation and connects a clutch by generated pressure, or an oil pump (for example, a plunger pump) by differential rotation )
And a differential-speed-sensitive coupling device for coupling the clutch by its discharge pressure.

The rolling elements of the cam mechanism are not limited to balls, and may be, for example, cylindrical or cylindrical rolling elements.

Further, the clutch is not limited to the multi-plate clutch, but may be another type of friction clutch such as a cone clutch.

Further, the differential device described in claim 4 limits the differential by the rotation restraining force of the coupling of claims 1 to 3, and uses the coupling of claims 1 to 3. Accordingly, the structure is simple, the number of parts is small, the reliability is high, and the cost is low, the size is small and light, and the in-vehicle property can be improved.

[0129]

The coupling according to the first aspect of the present invention differs from the conventional example in that the coupling has a torque transmission characteristic control mechanism for adjusting the position of the cam mechanism in the radial direction in accordance with the rotational speed. Since a simple control system is not used, the structure is simple, the number of parts is small, the reliability is high, the cost is low, the size is small and light, and the in-vehicle property can be improved.

Further, the coupling of the present invention can control the torque transmission characteristic of the differential rotation responsive type according to the rotation speed (vehicle speed) while having the above-mentioned advantages. , Maneuverability, stability, stack escape,
The fuel efficiency of the engine is greatly improved.

According to the second aspect of the invention, the same effect as that of the first aspect can be obtained, and the structure in which the urging force of the urging means is opposed to the centrifugal force of the rolling element has a very simple structure. In addition, the number of parts is small, the size is small and light, and the on-board property can be improved.

Further, the transmission torque characteristic is defined as the rotational speed (vehicle speed).
Can be controlled continuously in accordance with the change of the vehicle speed, so that the effect of improving the running performance, maneuverability, and stability of the vehicle is great.

According to the third aspect of the present invention, the same effects as those of the second aspect can be obtained, and the torque can be changed according to the rotational speed (vehicle speed) of the coupling by changing the cam angle according to the radial position. The transfer characteristics can be finely adjusted.

The differential device according to the fourth aspect uses the coupling according to the first to third aspects.
The structure is simple, the number of parts is small, the reliability is high, the cost is low, the size is small and light, and the on-board property can be improved.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a coupling according to a first embodiment.

FIG. 2 is a view taken in the direction of arrow A in FIG. 1 and shows a state at the time of low-speed running.

FIG. 3 is a view taken in the direction of arrow A in FIG. 1 and shows a state during high-speed running.

FIG. 4 is a graph showing that the characteristics of the differential rotation speed (△ N) and the transmission torque (T) of the coupling change with the vehicle speed.

FIG. 5 shows vehicle speed (S) and transmission torque (T) of the coupling.
6 is a graph showing characteristics of the present invention.

FIG. 6 is a cross-sectional view of a ball cam used for the coupling of the second embodiment, showing a state on a radially inner side.

FIG. 7 is a cross-sectional view of a ball cam used for the coupling of the second embodiment, showing a radially outer state.

FIG. 8 is a skeleton mechanism diagram showing a power system of a four-wheel drive vehicle using the coupling of the embodiment.

FIG. 9 is a sectional view of a conventional example.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Coupling 3 Rotation case (torque transmission member) 5 Inner shaft (torque transmission member) 7 Multi-plate clutch (clutch) 9 Differential rotation speed sensitive coupling device 11 Ball cam (cam mechanism) 17 Coil spring (torque transmission) Characteristic control mechanism: biasing means) 59, 61 Cam surface (cam groove) 63 Ball (rolling member) 81, 83 Cam surface (cam groove) with cam angle changed at radial position

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 3D042 AA02 AA03 AA05 AA06 AA10 AB02 AB17 CA01 CA09 CA12 CA14 CA16 CA18 CB04 3D043 AA02 AA03 AA05 AA06 AA10 AB02 AB17 EA02 EA18 EA20 EA38 EA42 EB02 EB01 EC02

Claims (4)

[Claims] 1. A clutch disposed between a pair of torque transmitting members, and both torques disposed between the two torque transmitting members via a differential rotation speed sensitive coupling device and received via the coupling device. A cam mechanism that presses and connects the clutch with a cam thrust force according to the differential rotation speed between the transmission members, and changes the point of action of the cam mechanism in the radial direction according to the rotation speed to rotate the torque transmission characteristics A coupling provided with a torque transmission characteristic control mechanism for controlling according to a speed. 2. The invention according to claim 1, wherein the cam mechanism comprises a cam groove provided in a radial direction and a rolling element movable on the cam groove, and the torque transmission characteristic control mechanism comprises:
A coupling as a biasing means for biasing a rolling element radially inward against its centrifugal force. 3. The coupling according to claim 2, wherein the angle of the cam groove is changed depending on the radial position. 4. A case rotating by the driving force of an engine.
A torque transmission member, a differential mechanism for distributing the rotation of the case-shaped torque transmission member to the wheels via a pair of shaft-shaped torque transmission members, and a clutch disposed between the torque transmission members. A differential device comprising: the coupling according to any one of claims 1 to 3, which limits a differential of the moving mechanism.