JP2709143B2 - Clutch device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a clutch device that switches a rotation transmission path according to a rotation difference between an input side and an output side.

[Conventional technology]

Normally, in a four-wheel drive vehicle that is driven by two wheels and transmits the driving force of the other two wheels to perform four-wheel drive when a difference in rotation speed occurs between the front and rear axles, the drive shaft and the differential A viscous coupling that switches the transmission path of rotation in accordance with the difference in rotation between the two is used.

This viscous coupling incorporates a number of plates connected to the input shaft and the housing and a highly viscous substance such as silicon oil inside the housing, and when the highly viscous substance is sheared by mutual rotation of the plates. The transmission of the rotational torque is switched between the housing and the input shaft by utilizing the shear force generated in the input shaft.

[Problems to be solved by the invention]

However, in the viscous coupling utilizing the shear force of a high-viscosity material as described above, the shear resistance of the high-viscosity material increases at low rotation, and the transmission torque increases. For this reason, the structure in which the viscous coupling is attached instead of the center differential has a disadvantage that the braking phenomenon of the tight corner cannot be completely eliminated.

When the coupling is operated for a long time, the temperature inside the coupling rises due to the resistance of the silicon oil to agitation, and the temperature rise causes the silicone oil to expand and the internal pressure to increase. May rise. Such an increase in the transmission torque is eliminated when the rotational speed decreases, and returns to the original torque transmission by viscous resistance.However, in order to eliminate the above-described characteristics, the amount and viscosity of the filled silicone oil must be reduced. It is necessary to control the temperature within a strict range, and there is a disadvantage that the assembling operation is troublesome.

The present invention has been made in view of the above-described drawbacks, and has as its object to provide a clutch device capable of performing stable torque transmission with a simple structure by mechanically switching transmission torque.

[Means for solving the problem]

In order to solve the above-mentioned problems, the present invention inserts an end of a first shaft into an internal hole of a bottomed cylindrical casing, and
One end of a second shaft arranged on the same axis is connected to an end of the shaft via a torsion bar, and a pressure receiving plate rotatably fitted to the internal hole is connected to the other end of the second shaft. Forming a layer of a highly viscous substance between the pressure receiving plate and the bottom surface of the internal hole, forming a cam surface on the outer diameter surface of the end of the first shaft, and forming a cam surface on the inner surface corresponding to the cam surface; An engaging sleeve having a cylindrical inner surface is attached to the inner surface, a retainer is incorporated between the cam surface and the cylindrical surface, and a relative rotation between the retainer and the first shaft is provided in a pocket provided in the retainer. And a resilient member for holding the engaging element at a position where the engaging element does not engage with the cylindrical surface and the cam surface. The retainer and the second shaft are And a structure in which the pins are connected by pins protruding in the radial direction.

In the above structure, the second shaft and the pressure receiving plate are rotatably provided, and one end of the spiral spring wound around the outer diameter of the second shaft is connected to the second shaft, and the other end is connected to the pressure receiving plate. Can be adopted.

[Action]

When the first shaft is connected to the front wheels, which are drive wheels, and the casing is connected to the rear wheels, the rotation applied to the first shaft tends to be transmitted to the second shaft via the torsion bar, but the casing is not connected to the rear shaft. Since it is swung by the wheel, the driving torque from the first shaft is not transmitted, and the coaxial rotation is maintained while being separated from the first shaft.

Now, when the rotation of the first shaft exceeds the rotation of the casing due to slippage of the front wheels, shear resistance is generated inside the highly viscous material layer between the second shaft and the casing, and the rotation of the second shaft is stopped. Force acts. For this reason, a rotation shift occurs between the first shaft and the second shaft, and the torsion bar connected to both of them is twisted.

When the torsion bar is twisted, the retainer connected to the second shaft rotates relatively to the first shaft, so that the engagement element engages with the cylindrical surface of the engagement sleeve and the cam surface of the first shaft, First
The rotation of the shaft is transmitted to the casing via the engaging element, and rotates the casing at the same rotation.

When the rotation of the first shaft and the casing becomes the same, the twist of the torsion bar is returned against the shear resistance of the high-viscosity material, so that the retainer rotates with respect to the first shaft and returns to the neutral position, The engagement of the engagement element is released. For this reason, the rotation of the first shaft returns to the original state, and the state is separated from the casing.

The transmission of power may be configured such that the casing side is used as the input side and the casing transmits torque from the casing to the first shaft via the second shaft.

〔Example〕

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

As shown in FIGS. 1 and 2, the casing 1 has a mounting hole 2 formed on one end surface and a cylindrical internal hole 3 formed on the other end surface. Axis 4
The end of has entered.

The first shaft 4 is provided with a shaft insertion hole 5 and a through hole 6 on a shaft core, and a second shaft 7 is inserted into the shaft insertion hole 5 and supported rotatably.

A torsion bar insertion hole 8 is provided at the tip end of the second shaft 7 that fits into the shaft insertion hole 5 so as to match the axis of the shaft, and the torsion bar insertion hole 8 and the through hole of the first shaft 4 are provided. 6
, A torsion bar 9 is rotatably inserted. At both ends of the torsion bar 9, locking pins 10 and 11 inserted radially into the first shaft 4 and the second shaft 7 respectively penetrate, and both ends of the torsion bar 9 are the first shaft. 4 and the second shaft 7 are connected so as to rotate integrally.

Further, a square shaft 12 is formed on the tip end surface of the second shaft 7, and the first shaft
The end face of the shaft insertion hole 5 of the shaft 4 is provided with a square hole 13 into which the square shaft 12 is loosely fitted.
And a gap in the rotation direction is provided.

A rear end of the second shaft 7 toward the back side of the casing 1 has a pressure receiving plate movably fitted in the internal hole 3 of the casing 1.
The 14 central holes 14a are inserted. At the end of the second shaft 7, a radial pin 16 that engages with a radial groove 15 provided along the central hole 14a is inserted, and the second shaft 7 and the pressure receiving plate 14 are rotated in the rotational direction. Are connected so as to move integrally. A pressure receiving plate is provided between the pressure receiving plate 14 and the end of the first shaft 4.
A coil spring 17 is provided for pressing the inner surface 3 against the bottom surface 3a of the inner hole 3, whereby a rotational torque of the second shaft 7 is applied to the pressure receiving plate 14.

The pressure receiving plate 14 is rotatably fitted to the second shaft 7 and the peripheral surface of the internal hole 3 via seal rings 18 and 19 fitted to the inner peripheral surface and the outer peripheral surface. A viscous layer 20 filled with a highly viscous substance is formed in a gap between the inner hole 3 and the bottom surface 3a. Silicon oil, silicone putty, or the like can be used as the high viscosity substance.

On the other hand, on the opening side of the internal hole 3, an engagement sleeve 23 whose inner diameter surface is a cylindrical surface 22 is fitted via a cushioning material 21, and both ends of the cylindrical surface 22 are paired with a pair of bearings 24. 24, the first shaft 4 is rotatably supported on the outer peripheral surface. A cam surface 25 that forms a wedge-shaped space with the cylindrical surface 22 is formed on the outer diameter surface of the first shaft 4 corresponding to the cylindrical surface 22.

Further, a pin insertion hole 26 is formed in the peripheral wall of the shaft insertion hole 5 of the first shaft 4.
A pin 27 is provided at the end of the second shaft 7 located in the shaft insertion hole 5 to extend in the radial direction and loosely fit in the pin insertion hole 26. Both ends of the pin 27 are provided. Cage 28
Are connected.

The retainer 28 is provided with a pocket 29 at a position facing the cam surface 25, and an engaging element 30 composed of a roller and an elastic member 31 are incorporated in the pocket 29. The engaging element 30 is held at a neutral position where the engaging element 30 does not engage with the cylindrical surface 22 and the cam surface 25 due to the elastic force of the elastic member 31 during normal operation.

The elastic member 31 is, as shown in FIG.
A pair of side plates 31b is provided at both ends of the base plate, and both end members of the side plate 31b are bent outward to form a pair of elastic pieces (not shown). Press the peripheral surface of 30.

This embodiment is constructed as described above,
A description will be given of a case where the operation of the clutch device of the embodiment is applied to a four-wheel drive vehicle that normally travels on the front wheels and changes to four wheels. In this case, the flange 32 attached to the first shaft 4 is connected to the drive shaft connected to the front wheel, and the casing 1
The differential which is connected to the rear wheel is connected to the mounting hole 2 on the rear end face of the rear end face to make the output side.

Now, when the flange 32 receives rotational torque from the drive shaft, the first shaft 4 rotates.
Also, it rotates together with the rear wheel and rotates at the same speed, so that no shear resistance is generated in the viscous layer 20, and the torsion bar 9 is not twisted. Therefore, the engaging element 30 is formed between the cylindrical surface 22 and the cam surface 25.
Is in the neutral position, and there is no transmission of torque via the engagement element 30, so that the casing 1 is freely hung by the rear wheel, and the braking phenomenon at the tight corner does not occur.

Now, when the front wheel slips and the rotation of the first shaft 4 becomes higher than the rotation of the casing 1, a rotation difference occurs between the second shaft 7 and the casing 1.
There is a difference between the movement of the viscous substance on the 14 side and the movement of the viscous substance on the bottom side of the internal hole 3. Therefore, a shear resistance is generated inside the viscous layer 20, and a force acts to stop the rotation of the pressure receiving plate 14 and the second shaft 7.

As a result, the second shaft 7 tends to shift with respect to the first shaft 4, and the torsion bar 9 is twisted.

The twisting of the torsion bar 9 in this manner is the same as the twisting of the retainer 28 by the second shaft 7 in the direction opposite to the rotation direction of the first shaft 4. Movement relative to the axis 4 rotates the retainer 28.

The engaging element 30 is pushed by the movement of the retainer 28 and the cylindrical surface is pressed.
The clutch 22 is engaged with the cam surface 25. Therefore, the rotation of the first shaft 4 is controlled by the casing 1 via the engagement element 30.
And the casing 1 rotates at the same rotation as the first shaft 4.

On the other hand, when the rotation of the casing 1 becomes the same as the rotation of the first shaft 4, the torsion bar 9 is no longer twisted, so that the second shaft 7 matches the untwisting of the torsion bar 9 and contradicts the shear resistance of the viscous layer. Try to return to the original state. For this reason, the engaging element 30 is pushed in the circumferential direction by contact with the cylindrical surface 22 to disengage the clutch, and the casing 1 rotates while being disconnected from the first shaft 4. However, at the next moment, the rotation of the first shaft 4 becomes higher than the rotation of the casing 1, so that the torsion bar 9 is again twisted and the clutch is engaged by the same action as above, and the first shaft 4 and the casing 1 rotate integrally. I do.

The above operation is repeated while the front wheels are traveling on a road surface with little friction, and the two-wheel drive becomes the four-wheel drive every time the front wheels slip, so that stable traveling can be performed.

Such a continuous clutch is disengaged when no slip occurs on the front wheels and the shear resistance inside the highly viscous substance is eliminated, and thereafter, the two wheels drive only the front wheels.

FIG. 3 and FIG. 4 show a second embodiment according to the present invention.

In this embodiment, the cam surface 25 of the first shaft 4 is a cylindrical surface,
Two retainers 33 and 34 having different diameters are incorporated between the cam surface 25 and the cylindrical surface 22 of the engagement sleeve 23, and the retainer 33 on the small diameter side is fixed to the first shaft 4, and the retainer 33 on the large diameter side is fixed. Hold the retainer 34 to the second shaft 7
Are connected by pins 27.

In addition, pockets 35,
A sprag 38 and an elastic member 39 are formed in the pockets 35 and 36 as engagement elements and formed on the arcuate surface 37 on the outer and inner diameter sides. Both ends of the sprag 38 are pushed by the elastic force of the elastic member 39, and the sprag 38 is held in a neutral state in which the arc-shaped surface 37 does not engage with the cylindrical surface 22 and the cam surface 25. When the torsion bar 9 is twisted and the first shaft 4 and the second shaft 7 rotate, and the large-diameter retainer 34 and the small-diameter retainer 33 rotate relatively, the sprags 38 are inclined and the arcuate surface 37 is formed. Engages the cylindrical surface 22 and the cam surface 25 to rotate the first shaft 4 and the casing integrally.

In the second embodiment, the second shaft 7 and the pressure receiving plate 14
Are fixed by screwing in, and a spring mounted between the pressure receiving plate 14 and the first shaft 4 is a disc spring 40 instead of a coil spring.

In both the first embodiment and the second embodiment, the first embodiment
The relative rotation of the shaft 4 and the second shaft 7 causes the engaging element 30 or sprag 38 to engage the cylindrical surface 22 and the cam surface 25, and the first shaft 4 and the casing 1 are connected by the engagement.

On the other hand, when relative rotation occurs due to a shocking force,
The square hole 13 and the square shaft 12 are engaged to directly transmit the rotation of the first shaft 4 to the second shaft 7, thereby preventing the torsion bar from being damaged due to excessive twisting.

FIG. 5 shows a third embodiment. The basic configuration of this embodiment is the same as that of the first embodiment,
The connection structure between the shaft 7 and the pressure receiving plate 41 is different.

That is, the pressure receiving plate 41 is formed in a cap shape, and the end of the second shaft 7 is inserted into the pressure receiving plate 41 so that both can freely rotate.

Further, one end of a spiral spring 42 wound around the outer periphery of the second shaft 7 is fixed to the second shaft 7, and the other end is fixed to the pressure receiving plate 41.

In the above structure, when a rotation difference occurs between the first shaft 4 and the casing 1, the second shaft 7 does not immediately receive the shear resistance from the viscous layer 20, but the second shaft 7 rotates to rotate the helical spring 42.
When the spring 42 is wound, the second shaft 7 rotates integrally with the pressure receiving plate 41 and receives a rotation resistance. In this case, the torsion bar 9 is twisted and the engaging element 30
Rotates relative to the first shaft 4 to engage the clutch,
The first shaft 4 and the casing 1 rotate integrally.

On the other hand, the above-mentioned clutch state is not immediately released even if the rotation difference between the first shaft 4 and the casing 1 is lost. That is, the spring resistance of the wound spiral spring 42,
Even when the torsion of the torsion bar 9 returns due to the surface pressure between the cam surface 25, the engaging member 31, and the cylindrical surface 22, the engaging member 31 does not immediately move from the engagement position, and the helical spring 42 is unwound. At the time when the resistance is lost, the elasticity of the elastic member 31
Is returned to the neutral position, thereby disengaging the clutch.

As described above, when the spring constant of the spiral spring 42 is changed to change the force relationship between the spring force and the torsional torque of the torsion bar 9, the time during which the clutch is engaged can be adjusted. Therefore, for example, it is possible to set the clutch to be automatically disengaged after the established state of the clutch is maintained for a certain period of time.

〔The invention's effect〕

As described above, the clutch device of the present invention uses the torsion bar torsion to engage the engaging element between the casing and the first shaft to thereby reduce the rotational torque to the first level.
Since the switching is performed mechanically between the shaft and the casing, the transmission torque can always be switched stably, and instability of operation such as a viscous coupling can be eliminated.

Further, since the number of parts is smaller than that of the viscous coupling, assembly is easy and a compact transmission device can be provided.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional front view showing a first embodiment according to the present invention,
FIG. 2 is a sectional view taken along the line II-II of FIG. 1, FIG. 3 is a longitudinal sectional front view showing the second embodiment, FIG. 4 is a sectional view taken along the line IV-IV of FIG. FIG. 5 is a vertical sectional front view showing the third embodiment. 1 ... casing, 3 ... internal hole, 4 ... first shaft, 5 ...
... Shaft insertion hole, 7 ... Second shaft, 9 ... Torsion bar, 14
... pressure receiving plate, 16 ... pin, 20 ... viscous layer, 22 ... cylindrical surface, 23 ... engagement sleeve, 25 ... cam surface, 27 ... pin,
28… Cage, 29… Pocket, 30… Engagement element, 31…
Elastic member, 33, 34 ... Cage, 35, 36 ... Pocket, 38
…… Sprag, 39 …… Elastic member, 41 …… Pressure receiving plate, 42 ……
Spiral spring.

Claims (2)

(57) [Claims] 1. An end of a first shaft is inserted into an inner hole of a bottomed cylindrical casing, and one end of a second shaft disposed on the same axis at the end of the first shaft through a torsion bar. And a pressure receiving plate rotatably fitted to the internal hole is connected to the other end of the second shaft, and a layer of a highly viscous substance is formed between the pressure receiving plate and the bottom surface of the internal hole. A cam surface is formed on the outer diameter surface of the end of the first shaft, and an engagement sleeve whose inner diameter surface is a cylindrical surface is attached to the inner surface of the internal hole corresponding to the cam surface. A retainer is incorporated between the retainers, and an engaging element that engages with the cylindrical surface and the cam surface by the relative rotation of the retainer and the first shaft is provided in a pocket provided in the retainer. An elastic member that holds the cam at a position where it does not engage with the cam surface is incorporated.
A clutch device connected by pins protruding radially from the shaft. 2. A second shaft and a pressure receiving plate are rotatably provided, and one end of a spiral spring wound around the outer diameter of the second shaft is connected to the second shaft, and the other end is connected to the pressure receiving plate. The clutch device according to 1).