JPH10238563A - Power transmission device - Google Patents

Abstract

(57) [Problem] To provide a visco-lock type power transmission device capable of setting an upper limit value of a transmission torque without generating abnormal noise or deteriorating durability. SOLUTION: A multi-plate clutch 4 interposed between first and second rotating members 2, 3 and a silicone oil is defined and defined between the first and second rotating members 2, 3. A pressure chamber 10,
The piston 5 is pressed by a feed disk 9 that rotates integrally with the first rotating member 2 in the pressure chamber 10 and a pressure of silicon oil generated between the feed disk 9 and the second rotating member 3, The piston pressing means 6 for bringing the plate clutch 4 into close contact, the reservoir 11 communicating with the pressure chamber 10 via the suction path 14, and the suction path 14 being closed by a predetermined pressure or higher generated in the pressure chamber 10, Control valve 30 for shutting off the supply of silicon oil to the
A detent ball 37 for locking the 30 valve elements 31 in the open position.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a power transmission device for transmitting a driving torque between rotating members relatively rotatable about the same axis.

[0002]

2. Description of the Related Art Conventionally, various types of driving for driving the front and rear wheels of a four-wheel drive vehicle have been developed. Among them, a viscous coupling is provided in the middle of a propeller shaft for transmitting driving torque to a rear wheel or a front wheel. In some cases, a driving torque is transmitted to a rear wheel or a front wheel when a rotational speed difference occurs between the front and rear wheels. According to this drive type, not only can a drive torque be transmitted to the rear wheels or the front wheels as soon as a rotational speed difference occurs between the front and rear wheels, but also the occurrence of a tight corner braking phenomenon can be prevented. It has various excellent features, such as being able to prevent rotational interference between them. However, since the viscous coupling transmits a driving torque using viscous resistance generated between thin plates that rotate relatively in a high-viscosity fluid,
There is naturally a limit to the drive torque that can be transmitted, and it is not suitable for transmitting large torque.

[0003] Therefore, a friction clutch interposed between first and second rotatable members that can rotate relative to each other, and a pressure clutch defined between the first and second rotatable members and filled with a highly viscous fluid. A rotating body that rotates relative to a second rotating member by integrally rotating with the first rotating member in the pressure chamber, and the rotating body that is generated between the rotating body and the second rotating member. Pressing the piston by the pressure of the highly viscous fluid,
There has been proposed a power transmission device called a so-called viscolock, which includes a piston pressing means for bringing the friction clutch into close contact with each other and is capable of transmitting a large torque.

The structure and operating principle of this viscolock type power transmission device are described in SAE Technical Paper No. 96.
0718 and Japanese Patent Application Laid-Open No. Hei 7-197954, and a detailed description thereof will be omitted here. However, the outline of this viscolock type power transmission device will be described below with reference to FIG.
This will be described with reference to FIG.

[0005] A power transmission device 1 shown in FIG. 5 includes first and second rotating members 2 and 3 which are relatively rotatable around a rotation axis C, and a power transmission device 1 between the first and second rotating members 2 and 3. A multi-plate clutch 4 as a friction clutch, a pressure chamber 10 defined between the first and second rotating members 2 and 3 and filled with a high-viscosity fluid; The feed disk 9 which is a rotating body that can rotate relative to the second rotating member 3 by rotating integrally with the first rotating member 2, and the feed disk 9 and the second rotating member 3 The piston 5 is pressed by the pressure of the high-viscosity fluid generated between the piston 5 and the piston pressing means 6 for bringing the multi-plate clutch 4 into close contact with the pressure chamber 10 via the suction passage 14.
And a reservoir 11 communicating with the reservoir.

The piston pressing means 6 includes a rotating case 7 that rotates integrally with the second rotating member 3, and a pump disk that can swing relative to the rotating case 7 around a rotation axis C within a predetermined angle range. 8 is provided. A compensating piston 13 urged by a disc spring 12 is fitted into a reservoir 11 which is arranged on the opposite side of the rotary case 7 from the pump disk 8 and communicates with the pressure chamber 10 via a suction passage 14. The change in the capacity of the silicone oil in the pressure chamber 10 is compensated. The piston 5 is urged by a disc spring 19 in a direction away from the multi-plate clutch 4.

The first and second rotating members 2 and 3
Rotate relative to each other, and when the feed disk 9 is rotationally displaced leftward in the figure with respect to the rotating case 7 as shown in FIG.
Since the pump disk 8 rotates relative to the feed disk 9 by a predetermined angle in the left direction in the figure, the pressure chamber 1
Numeral 0 communicates with the reservoir 11 through a communication hole 15 formed through the suction passage 14 and the pump disk. And
When the high-viscosity fluid in the circumferential groove 16 recessed in the pump disk 8 moves together with the feed disk 9, the high-viscosity fluid in the reservoir 11 is gradually fed into the pressure chamber 10, and The pressure in 10 gradually increases.
As a result, the piston 5 receiving the pressure in the pressure chamber 10 presses the multi-plate clutch 4, so that the plates constituting the multi-plate clutch 4 come into close contact with each other and the first and second rotating members 2 and 3 Transmits the driving torque.

[0008]

In the viscolock type power transmission device 1 described above, the magnitude of the driving force that can be transmitted between the first and second rotating members 2 and 3 is the first and second rotation members. Although the pressure in the pressure chamber 10 is released into the reservoir 11 by using a relief valve, depending on the relative rotational speed difference between the two rotating members 2 and 3, the driving force that the multi-plate clutch 4 can transmit is reduced. A torque limiter function for setting the upper limit can be added.

However, if the pressure in the pressure chamber 10 is simply released to the reservoir 11 by using the relief valve, chattering occurs in the relief valve when the pressure is balanced, thereby exciting abnormal vibrations or causing the multi-plate clutch 4 to fail. There is a problem that the plate may be dragged continuously at all times, which causes problems such as generation of abnormal noise and deterioration of durability. In view of the above, an object of the present invention is to solve the above-described problems, and to provide a visco-lock type power transmission device capable of setting an upper limit value of a transmission torque without generating abnormal noise or deteriorating durability. Is to do.

[0010]

SUMMARY OF THE INVENTION The object of the present invention is to provide first and second rotating members which are relatively rotatable about the same axis, and are interposed between the first and second rotating members. A friction clutch, a pressure chamber defined between the first and second rotating members and filled with a high-viscosity fluid, and a second rotating member integrally rotating with the first rotating member in the pressure chamber. A rotating body that relatively rotates with respect to the rotating member, and a piston pressing means that presses a piston by the pressure of the high-viscosity fluid generated between the rotating body and the second rotating member, thereby bringing the friction clutch into close contact with the rotating body. A reservoir communicating with the pressure chamber via a suction path, and closing the suction path by a predetermined pressure or higher generated in the pressure chamber to shut off the supply of the highly viscous fluid from the reservoir to the pressure chamber. A control valve and a predetermined It can be achieved by a power transmission device provided with a locking means for locking the open position the control valve with a locking force.

According to the above configuration, when the pressure in the pressure chamber reaches a predetermined pressure or more, the control valve closes the suction passage against the locking force of the locking means, and the high viscosity fluid from the reservoir to the pressure chamber. Since the supply of the fluid is shut off, the pressure in the pressure chamber does not increase to a predetermined pressure or more. Thus, an upper limit can be set for the drive torque that can be transmitted by the friction clutch between the first and second rotating members. Further, the control valve closes the suction passage by the pressure of the high-viscosity fluid of a predetermined or more resistance against the locking force of the locking means, but when the suction path is opened, the locking force of the locking means is reduced. Does not act on control valve. Therefore, the return pressure when the control valve opens the suction passage becomes smaller than the operating pressure when the suction passage closes, and the control valve has a so-called hysteresis characteristic, and chattering hardly occurs even when the pressure is balanced.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a power transmission device according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.
FIG. 1 is a partial cross-sectional view showing a power transmission device according to an embodiment of the present invention, FIG. 2 is an enlarged cross-sectional view of the control valve shown in FIG. 1, and FIGS. 3 and 4 show the operation of the control valve shown in FIG. FIG. 4 is a cross-sectional view for explaining the above.

The power transmission device 1 according to the embodiment shown in FIG.
Reference numeral 00 denotes a case in which the rotary case 7 of the conventional viscolock type power transmission device 1 shown in FIG. 5 is replaced with a rotary case 20 and a control valve 30 is incorporated in the rotary case 20. It has the same structure. Thereby, the same components as those of the conventional power transmission device 1 shown in FIG.

As shown in FIG. 1, the power transmission device 100 of the present embodiment has a rotation axis C
It comprises a first rotating member 2 that is driven to rotate around, and a second rotating member 3 that is rotatable relative to the first rotating member 2 around the rotation axis C. The second rotating member 3 is connected to a driven member (not shown). A multi-plate clutch 4 as a friction clutch and a piston pressing means 6 for pressing a piston 5 for making the multi-plate clutch 4 adhere are interposed between the first and second rotating members 2 and 3, respectively. Have been.

The multi-plate clutch 4 includes a first rotating member 2
A plurality of inner plates 4a engaged in the rotational direction with
A plurality of outer plates 4b alternately arranged with the inner plates 4a and engaged with the second rotating member 3 in the rotational direction, and a plurality of outer plates 4b, 4b, Mounted annular spacer 6
a. The inner plate 4a and the outer plate 4b are configured to be pressed by the piston 5 of the piston pressing means 6 to be in close contact with each other and to transmit a driving torque between the first and second rotating members 2 and 3. ing.

The piston 5 of the piston pressing means 6 is
The pressure chamber 10 is fitted inside the second rotating member 3 and is displaceable in the direction of the rotation axis C, and forms a pressure chamber 10 together with the second rotating member 3. The pressure chamber 10 is sealed with silicone oil as a highly viscous fluid. In the pressure chamber 10, an annular pump disk 8, which is rotatable coaxially relative to the second rotating member 3 within a predetermined angle range, and rotates integrally with the first rotating member 2. An annular feed disk 9 is disposed as a rotating body that rotates. The piston 5 is always urged by a disc spring 19 in a direction away from the multiple disc clutch 4.

On the other hand, the multi-plate clutch 4 of the second rotating member 3
A compensating piston 13 constantly urged by a disc spring 12 is slidably fitted in the direction of the rotation axis C in a reservoir 11 formed at the end opposite to the above. The pressure chamber 10 and the reservoir 11 communicate with each other through a suction passage 14 penetrating through the rotary case 20 and a communication hole 15 penetrating through the pump disk 8 to increase or decrease the amount of silicon oil in the pressure chamber 10. Is compensated for.

Further, the power transmission device 100 of the present embodiment
Is provided with a control valve 30 capable of opening and closing the suction passage 14 provided through the rotary case 20 as shown in FIG. The control valve 30 is housed in the control valve housing portion 21 of the rotating case 20 as shown in FIG. 2, and is slidable in a direction perpendicular to the rotation axis C (left and right directions in the drawing). It has a valve body 31. The valve element 31 is connected to a block-shaped central portion 32 symmetrically with respect to the central portion 32, and has a pair of left and right suction passages 14 </ b> L, 1.
A plate-shaped body portion 33 capable of opening and closing the 4R,
34. A detent ball 37 urged in an engagement direction by an urging spring 36 is engaged with a detent groove 35 formed on the surface of the central portion 32, and the valve element 31 of the control valve 30 is provided. The locking means is configured to lock at a release position with a predetermined locking force.

As shown in FIG. 2, the valve body 31 is moved forward by receiving the pressure in the pressure chamber 10, and the suction passages 14L, 1
A pair of left and right cylinder chambers 22 and 23 as a control valve forward movement means for closing the 4R are formed together with the rotating case 20. Further, in the cylinder chambers 22, 23, biasing springs 38, 39 as control valve return means for opening the suction passages 14L, 14R by returning the valve body 31 are respectively incorporated. The cylinder chambers 22 and 23 are provided with orifices 24 and 25 for discharging the silicone oil in the cylinder chambers 22 and 23 to the suction passage 14, respectively. Further, a pair of left and right pilot flow paths 26L and 26R for introducing the pressure in the pressure chamber 10 into the pair of left and right cylinder chambers 22 and 23 are formed in the rotary case 20 in communication grooves 18 formed in the rotary case 20 respectively. It is provided so as to extend in the shape of a crank with the.

Next, the operation of the power transmission device 100 of the present embodiment configured as described above will be described. In addition,
In the following description, the case where the feed disk 9 is displaced relative to the rotating case 20 in the left direction in the figure will be described, but the same applies to the case where the feed disk 9 is displaced in the opposite direction.

When the first and second rotating members 2 and 3 rotate relative to each other, and the feed disk 9 rotates relative to the rotating case 20 in the leftward direction in the drawing as shown in FIG. The pump disk 8 is swung leftward in the figure by the viscosity of the silicon oil.
Then, the pump disk 8 engages with a stopper (not shown) provided on the rotary case 20 and stops while fully swinging to the left in the figure.

In this state, as shown in FIG. 3, the suction passage 14L on the left side of the rotary case 20 and the communication hole 15L on the left side of the pump disk 8 face each other and are recessed in the pump disk 8. The circumferential groove 16 communicates with the reservoir 11. The communication groove 18 of the rotating case 20 and the communication hole 15R on the right side of the pump disk 8 in the drawing oppose each other, and the circumferential groove 16 and the communication groove 18 communicate with each other. However, the suction passage 14 </ b> R on the right side of the rotating case 20 in the drawing is closed by the pump disk 8. Furthermore, a pair of left and right pilot flow paths 26L, 26R
The pilot flow path 26L communicating with the cylinder chamber 22 on the right side in the drawing is connected to the circumferential groove 1 through the communication hole 15R.
The pilot flow passage 26 </ b> R communicating with the cylinder chamber 23 on the left side in the figure is closed by the pump disk 8.

When the first and second rotating members 2 and 3 rotate relative to each other and the feed disc 9 continuously rotates relative to the left side in the pressure chamber 10, the silicon oil in the pressure chamber 10 is transferred to the feed disc 9. The pump disk 8 moves in the circumferential groove 16 of the pump disk 8 to the left in the drawing. As a result, the silicone oil in the reservoir 11 is supplied to the suction passage 14L.
And is continuously fed into the circumferential groove 16 through the communication hole 15L. The silicone oil, which has rotated around the feed groove 9 in the circumferential groove 16 in the circumferential direction by about one turn, enters the communication groove 18 when it reaches the communication hole 15R on the right side in the figure. Then, it moves inside the communication groove 18 to the outside in the radial direction of the rotary case 20, gets over the outer peripheral portion of the pump disk 8, and fills the pressure chamber 10.

On the other hand, the silicone oil in the circumferential groove 16 is introduced into the cylinder chamber 22 on the right side in the drawing via the communication hole 15R and the pilot flow path 26L. Then, the gas leaks from the orifice 24 formed in the cylinder chamber 22 to the suction passage 14 </ b> R on the right side in the drawing, and returns to the reservoir 11.
Therefore, when the amount of the silicon oil introduced from the reservoir 11 into the circumferential groove 16 of the pump disk 8 exceeds the amount of the silicon oil leaking from the orifice 24, the pressure in the pressure chamber 10 gradually increases.

When the pressure in the pressure chamber 10 increases, the pressure in the cylinder chamber 22 also increases. Thereby, the control valve 30
Is pressed and urged leftward in the figure by the pressure of the silicon oil in the cylinder chamber 22. However, the urging force of the urging spring 39 built in the cylinder chamber 23 on the left side in the drawing and the locking force of the detent ball 37 engaging with the detent groove 35 act on the valve body 31. As a result, as long as the urging force of the silicone oil in the cylinder chamber 22 does not exceed the resultant force of the spring urging force and the locking, the valve element 31 cannot move leftward in the drawing.

Therefore, the valve element 31 of the control valve 30 remains in the neutral position until the relative rotation speed between the first and second rotating members 2 and 3 increases and the pressure in the pressure chamber 10 sufficiently increases. The suction passage 1 of the rotating case 20 remains stopped.
Release 4L. That is, in a region where the relative rotational speed between the first and second rotating members 2 and 3 is low, the pressure in the pressure chamber 10 that presses the piston 5 toward the multi-plate clutch 4 is insufficiently increased. The disc spring 19 remains separated from the multiple disc clutch 4. Thereby, the inner plate 4a and the outer plate 4b of the multi-plate clutch 4
And the driving torque cannot be transmitted by the multi-plate clutch 4.

On the other hand, when the relative rotational speed between the first and second rotating members 2 and 3 increases, the pressure in the pressure chamber 10 increases, and the piston 5 pressurizes the silicon oil in the pressure chamber 10. As a result, it is pressed toward the multi-plate clutch 4. When the pressing force for pressing the piston 5 exceeds the urging force of the disc spring 19, the piston 5 is displaced toward the multi-plate clutch 4, and
The multi-plate clutch 4 is pressed via the spacer 6a to bring the inner plate 4a and the outer plate 4b into close contact with each other. Accordingly, in a region where the relative rotation speed between the first and second rotating members 2 and 3 is high, the inner plate 4a and the outer plate 4b are in close contact with each other, and the first and second rotating members 2 and 3 have many gaps. Drive torque is transmitted via the plate clutch 4.

When the first and second relative rotational speeds further increase and the pressure in the pressure chamber 10 gradually increases, the cylinder chamber 2 communicating with the pressure chamber 10 via the pilot flow path 26L.
The pressure in 2 also gradually increases. When the urging force for pressing the valve element 31 exceeds the combined force of the spring urging force of the urging spring 39 and the locking force of the detent ball 37, the valve element 31 moves to the left side in the drawing as shown in FIG. It is moved forward. At this time, since the silicon oil in the cylinder chamber 23 on the left side in the figure is gradually discharged into the suction passage 14L through the orifice 25, the valve element 31 does not suddenly move forward. Further, by adjusting the magnitude of the urging force of the urging spring 39 and the magnitude of the urging force of the urging spring 36 for urging the detent ball 37 in the engagement direction, the cylinder when the valve element 31 moves forward is adjusted. The operating pressure in the chamber 22 can be set freely.

When the valve element 31 of the control valve 30 moves to the left side in the drawing and closes the suction passage 14L on the left side in the drawing, the reservoir 11
The supply of silicone oil from the pump to the circumferential groove 16 of the pump disk 8 is shut off. As a result, the rotation of the feed disk 9 makes it impossible to feed the silicon oil from the reservoir 11 into the pressure chamber 10, so that the pressure in the pressure chamber 10 stops increasing. Then, the silicon oil in the cylinder chamber 22 leaks into the suction passage 14R on the right side in the drawing via the orifice 24, so that the pressure in the pressure chamber 10 gradually decreases until it becomes equal to the pressure in the reservoir 11.

On the other hand, the valve element 31 of the control valve 30
After closing L, when the pressure in the pressure chamber 10 gradually decreases and the pressure in the cylinder chamber 22 decreases to a predetermined pressure, the urging spring 39 built in the cylinder chamber 23 opens the valve body 3.
The spring urging force for urging the valve 1 in the opening direction exceeds the pressing force of the silicone oil in the cylinder chamber 22 for urging the valve element 31 in the closing direction. Then, the valve element 31 is moved to the urging spring 3.
9 by the spring urging force. When the detent ball 37 is engaged with the detent groove 35, the valve element 31 stops at the neutral position where both the pair of left and right suction paths 14L and 14R are opened, and returns to the state shown in FIG. 1 or FIG.

That is, the power transmission device 10 of the present embodiment
At 0, when the pressure in the pressure chamber 10 rises to a predetermined pressure, the control valve 30 cuts off the communication between the pressure chamber 10 and the reservoir 11, so that the pressure in the pressure chamber 10 rises above a predetermined level. Can not. Thereby, an upper limit can be set for the drive torque that can be transmitted by the multiple disc clutch 4 between the first and second rotating members 2 and 3. The upper limit of the driving torque is adjusted by appropriately adjusting the spring urging force of the urging spring 39, the spring urging force of the urging spring 36 for urging the detent ball 37 in the engagement direction, and the shape of the detent groove 35. It can be changed to any value.

After the control valve 30 once interrupts the communication between the pressure chamber 10 and the reservoir 11, the control valve 30 keeps the pressure chamber 1 until the pressure in the pressure chamber 10 decreases to a predetermined lower limit.
The communication between 0 and the reservoir 11 is kept in a disconnected state.
Thereby, regardless of the relative rotation speed between the first and second rotating members 2 and 3, the pressure in the pressure chamber 10 does not increase again. When the valve element 31 is displaced in the closing direction from the open position, the detent ball 37 is engaged with the detent groove 35 of the valve element 31 to apply a resistance to the displacement of the valve element 31. When the valve element 31 is displaced in the opening direction from the closed position, no resistance acts on the displacement of the valve element 31. That is, the return pressure in the pressure chamber 10 when the valve body 31 opens the suction passage 14L becomes smaller than the operating pressure when the suction passage 14L is closed. Therefore, the control valve 30
It has a so-called hysteresis characteristic, and chattering hardly occurs even when pressure is balanced.

Therefore, the power transmission device 100 of the present embodiment
According to the above, chattering does not occur in the control valve 30, there is no possibility that abnormal vibration is excited or the plate of the multiple disc clutch 4 is constantly dragged, and generation of abnormal noise and deterioration of durability can be prevented. it can. As described above, each embodiment of the power transmission device according to the present invention has been described in detail. However, it is needless to say that the present invention is not limited to the above-described embodiment, and various changes can be made. For example,
In the above-described embodiment, the case where the driving torque is transmitted from the first rotating member 2 to the second rotating member 3 has been described, but the driving torque is transmitted from the second rotating member 3 to the first rotating member 2. You can also.

[0034]

As is apparent from the above description, according to the viscolock-type power transmission device of the present invention, when the pressure in the pressure chamber reaches a predetermined level or more, the control valve is locked by the locking means. Since the suction passage is closed against the force and the supply of the high-viscosity fluid from the reservoir to the pressure chamber is shut off, the pressure in the pressure chamber does not rise to a predetermined pressure or more. Thus, an upper limit can be set for the drive torque that can be transmitted by the friction clutch between the first and second rotating members. Further, the control valve closes the suction passage by the pressure of the high-viscosity fluid of a predetermined or more resistance against the locking force of the locking means, but when the suction path is opened, the locking force of the locking means is reduced. Does not act on control valve.
Therefore, the return pressure when the control valve opens the suction passage becomes smaller than the operating pressure when the suction passage closes, and the control valve has a so-called hysteresis characteristic, and chattering hardly occurs even when the pressure is balanced. Therefore, in the power transmission device of the present invention, chattering does not occur in the control valve, there is no possibility that abnormal vibration is excited or the plate of the multi-plate clutch is constantly dragged, and generation of abnormal noise and deterioration of durability are reduced. Can be prevented.

[Brief description of the drawings]

FIG. 1 is a partial cross-sectional view illustrating a power transmission device according to an embodiment of the present invention.

FIG. 2 is an enlarged sectional view of the control valve shown in FIG.

FIG. 3 is a sectional view for explaining the operation of the control valve shown in FIG. 2;

FIG. 4 is a sectional view for explaining the operation of the control valve shown in FIG. 2;

FIG. 5 is a partial sectional view of a conventional viscolock type power transmission device.

FIG. 6 is a partial cross-sectional view for explaining operations of the pump disk and the feed disk shown in FIG.

[Explanation of symbols]

 2 First rotating member 3 Second rotating member 4 Multi-plate clutch 5 Piston 6 Piston pressing means 8 Pump disk 9 Feed disk 10 Pressure chamber 11 Reservoir 13 Compensation piston 14 Suction path 15 Communication hole 16 Circumferential groove 18 Communication groove Reference Signs List 20 rotation case 30 control valve 31 valve body 35 detent groove 37 detent ball 100 power transmission device

Claims (1)

[Claims] A first rotating member rotatable relative to the same axis; a friction clutch interposed between the first and second rotating members;
A pressure chamber defined between the rotating members and filled with a high-viscosity fluid; and a rotation that rotates relative to the second rotating member by rotating integrally with the first rotating member in the pressure chamber. Body, the piston is pressed by the pressure of the highly viscous fluid generated between the rotating body and the second rotating member,
A piston pressing means for bringing the friction clutch into close contact, a reservoir communicating with the pressure chamber via a suction path, and closing the suction path by a predetermined pressure or higher generated in the pressure chamber to move from the reservoir to the pressure chamber. And a locking means for locking the control valve at an open position with a predetermined locking force.