JPH0697057B2 - Viscous coupling - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Object of the Invention (Industrial field of application) The present invention relates to a viscous coupling that transmits torque via a viscous fluid.

(Prior Art) Japanese Patent Laid-Open No. 61-65918 describes a "liquid friction clutch". This is a viscous coupling that transmits torque by virtue of the shear resistance of the viscous fluid between the plates that are individually engaged with the pair of transmission members.

(Problems to be Solved by the Invention) Disc springs are arranged between the plates, and when the plates are axially pressed by the pressing body, the disc springs bend and the entire plate moves and the plate interval becomes narrower. When the pressing force is reduced, the plate spacing is increased due to the biasing force of the disc spring.
In this way, the torque transmission characteristic can be changed.

However, the movement stroke on the operating side becomes very long, which is equal to the number of plates times the plate spacing, and the plates are greatly resisted by the viscous fluid during movement. Therefore, the response at the time of characteristic adjustment is poor. This is remarkable when the plate interval is widened by the disc spring. Further, since the stroke is large, a large pressing force is required, so that the pressing means becomes large.

Therefore, an object of the present invention is to provide a viscous coupling that has a fast response when adjusting the torque transmission characteristics and a small operating force required for the adjustment.

[Structure of the Invention] (Means for Solving the Problems) A viscous coupling according to the present invention includes first and second transmission members arranged so as to be relatively rotatable, a working chamber in which a viscous fluid is sealed, A first plate that non-rotatably engages the first transmission member in the working chamber, and a second plate that is arranged so as to sandwich the first plate and non-rotatably engages the second transmission member, respectively. And a third plate, and adjusting means for relatively moving the second and third plates in the axial direction via the operation force transmitting means so as to change the plate distance between the first plate and the first plate. To do.

(Operation) When the second and third plates are relatively moved by the operating force transmitting means by the operating force from the adjusting means and the plate gap between these and the first plate is narrowed, the transmission torque increases. Similarly, if the plate spacing is widened, the transmission torque becomes smaller. In this way, the torque transmission characteristic can be adjusted. At this time, the second plate and the third plate are moved in opposite directions with the first plate interposed therebetween,
The movement stroke of each plate is small because even if there are many combinations of the first, second, and third plates, the clearance is one set, and the response when adjusting the torque transmission characteristics is extremely fast, and the movement operation force is also large. The adjustment means can be made small because it is small.

(Embodiment) An embodiment will be described with reference to FIGS. 1 to 5. Fifth
The figure shows the power system of a 4WD vehicle using this embodiment. Less than,
The left and right directions are the left and right directions in FIGS. 1 and 4, and the left side corresponds to the front of the vehicle (upper side in FIG. 5).
It should be noted that members and the like without numbers are not shown.

First, the structure of the power system of this vehicle will be described with reference to FIG. This power system includes an engine 1, a transmission 3, a front diff 5 (a front wheel differential device), left and right front wheels 7 and 9, a transfer 11, a viscous coupling 13 of an embodiment, a propeller shaft 15, and a rear diff 17.
(Rear wheel side differential device), left and right rear wheels 19,21
Etc.

Next, referring to FIGS. 1 to 4, a viscous coupling is shown.
The configuration of 13 will be described.

The housing 23 (first transmission member) and the hub 25 (second transmission member) are arranged so as to be rotatable relative to each other. The hub 25 is spline-fitted to the transmission shaft 27 so that the housing 23 and the transmission shaft 27
A bearing 29 is arranged between and. bearing
To secure 29 axially, the transmission shaft 27 has a washer 31
The lock nut 33 is attached to the housing 23, and the retaining ring 35 is attached to the housing 23. The housing 23 is flange-connected to the transfer 11 side by a bolt screwed into the bolt hole 37, and the transmission shaft 27 is connected to the propeller shaft 15 side. A pressing member 39 is arranged between the inner circumference of the housing 23 and the outer circumference of the transmission shaft 27 so as to be movable in the axial direction and relatively rotatable, and a bearing 41 and a seal 43 are provided between the member 39 and the housing 23. And are arranged.

A working chamber 45 is provided between the housing 23, the hub 25 and the pressing member 39.
The working chamber 45 is filled with high-viscosity silicone oil (viscous fluid). Housing 23 and hub 25
X-rings 47, 49 (seal with X-shaped cross section) are respectively arranged between the member 39 and the member 39, and an O-ring 51 is arranged between the hub 25 and the member 39 to liquid-tighten the working chamber 45. Keep it at.

In the working chamber 45, a first plate 55 is spline-coupled to the inner periphery of the housing 23 so as to be axially movable. Since the wave washer 57 is arranged between the plate 55 and the retaining ring 56 at the left end portion, and the spacer ring 58 is provided between the plates 55,
The 55s are biased to the right so that the distance between them is kept constant. On the left side of each plate 55 is a second plate 59
Are arranged, and the third plate 61 is arranged on the right side so as to sandwich each plate 55.

As shown in FIG. 2, convex portions 63 and concave portions 65 are provided alternately on the inner edge side of these plates 59 and 61 along the circumferential direction, and slits 66 are provided on the outer edge side. . As shown in FIG. 3, the hub 25 is provided with an axial groove 67 on the outer periphery of which the projection 63 can be engaged, and each plate 59, 61 engages the projection 63 with this groove 67. is doing. As shown in FIGS. 4 (a) and 4 (b), the convex portions 63 of the plates 59 and 61 face each other, and the convex portions 63 of one plate face the concave portions 65 of the other plate. And is non-rotatably engaged with the hub 25. Further, as shown in the figure, cylindrical pieces 69, 71 engaging with the groove 67 are arranged between the convex portions 63 of the plates 59, 61 so as to penetrate the concave portions 65 on the other side. . Note that FIG. 4 shows each piece 6 for explanation.
The cross section of 9,71 is expanded and shown, and the pieces 69, 71 are actually arranged on the same circumference. Also, wave washer 5
The illustration of the 7,75 and the spacer ring 58 is also omitted.

The second plate 59 is arranged on the leftmost side, and the pressure receiving ring 73 is attached to the hub 25 on the left side thereof. A third plate 61 is arranged on the rightmost side, and a piece 71 is also arranged on the right side thereof, and the piece 71 is in contact with the pressing member 39. In addition, a piece 69, 61 is provided between each pair of plates 59, 61 separated by the plate 55.
The wave washer 75 is arranged on the outer side in the radial direction of 71, and the third
The plate 61 is elastically biased rightward. As described above, the second plate 59 is restricted from moving leftward by the pressure receiving ring 73, and the third plate 61 is movable left and right.

On the right side of the housing 23, a ring-shaped cylinder member 77 fixed to the vehicle body side is arranged coaxially with the transmission shaft 27. A bearing 79 is arranged between the member 77 and the transmission shaft 27. A piston 81 is fitted in the cylinder member 77 so as to be movable in the axial direction. The sliding parts of the cylinder member 77 and the piston 81 are kept liquid-tight by the O-rings 83 and 85. Thus
A hydraulic actuator 87 (adjusting means) is configured.
Hydraulic pressure is supplied to the actuator 87 from a hydraulic source via a control valve device and a hydraulic port 89. The piston 81 is connected to the pressing member 39 via a bearing 91. Therefore,
The hydraulic actuator 87 supplied with the hydraulic pressure pushes the third plate 61 to the left via the above-mentioned bridges 69, 71, wave washers 57, 75, and the pressing member 39, which are operating force transmitting means. The actuator 87 can be manually operated from the driver's seat, or can be automatically operated so as to stop the operation according to steering conditions, road conditions, or during braking.

In this way, the viscous coupling 13 is constituted.

Next, the function of the viscous coupling 13 will be described.

When the housing 23 rotates due to the driving force from the engine 1, this rotation is transmitted from the plate 55 to the plates 59 and 61 by the shear resistance of the silcon oil, causing the hub 25 to rotate. At this time, if the rotation difference between the housing 23 and the hub 25 is large, the differential limiting force becomes strong and a large torque is transmitted. If this rotation difference is small, the differential is allowed and the transmission torque becomes small.

In the state in which the pressing force from the actuator 87 is not applied, the second and third plates 59 and 61 and the first plate 55 are moved by the urging forces of the wave washers 75 and 57, as shown in FIG.
It is at the position shown in FIG. At this position, the plates 59 and 61 between the plates 55 come into contact with each other, and the plate distance between them and the plate 55 is maximized, and the shear resistance acting on the silicone oil is minimized. Therefore, the transmission torque is minimized.

When the third plate 61 is pushed to the left by the actuator 87, the plates 61 are moved to the left side plate 55.
Is pressed to move it to the left and bring it into contact with the plate 59 on the left side thereof as shown in FIGS. 1 (c) and 4 (b). Thus, in this state, the plates 59 and 61 are in contact with the plate 55 from the left and right, and the housing 23 and the hub 25 are in a torque transmission state due to friction between the plates. Therefore, the transmission torque becomes maximum.

When the hydraulic pressure supply is stopped and the pressing force by the hydraulic actuator 87 is released, the plates 59 and 61 are moved to the positions shown in FIGS. 1 (b) and 4 (a) by the elastic biasing force of the wave washers 57 and 75 as described above. The torque is pushed back to the position, and the plate distance between the plates 59, 61 and the plate 55 becomes maximum, so that the transmission torque returns to the minimum state. The transmission torque can be arbitrarily adjusted between the maximum and minimum by adjusting the plate spacing between the plates 59, 61 and the plate 55 by adjusting the pressing force of the actuator 87. Further, at this time, the second and third plates 59, 61 are moved relative to each other in the opposite directions with the first plate 55 interposed therebetween, so that the stroke of each plate is small and the pressing force can be small. Unlike the example, the response in adjusting the torque transmission characteristic is extremely fast, and the adjusting means can be downsized. Further, the wave washers 57, 75 have a longer stroke than the disc spring used in the conventional example, and the spring constant can be reduced. For this reason also, the pressing force can be reduced and the adjusting means can be downsized. Since the stroke of the plate is extremely small, it is possible to use the wave washer having such advantages without affecting the response.

Next, the function of the viscous coupling 13 according to the power performance of the vehicle shown in FIG. 5 will be described.

The rotation of the engine 1 is changed by the transmission 3 and is split from the front differential 5 to the left and right front wheels 7 and 9, and is also transmitted from the transfer 11 to the viscous coupling 13, the propeller shaft 15, and the rear differential 17, and the left and right rear wheels 19 and 21.
It is output separately.

Due to the characteristics of the viscous coupling 13, almost no driving force is transmitted to the rear wheels 19 and 21 when the difference in rotation between the front and rear wheels is small, such as when traveling on a good road. Therefore, the vehicle is in a substantially two-wheel drive state in which front wheels are driven, and fuel consumption is improved.

When the front wheels 7 and 9 run idle on a bad road or the like and a difference in rotation occurs between the front and rear wheels, the driving force is transmitted to the rear wheels 19 and 21 via the viscous coupling 13, and high running performance is obtained. Further, since a small rotation difference generated between the front and rear wheels during turning is absorbed by the viscous coupling 13, smooth turning can be performed. Even when the vehicle is turning into a garage or making a sharp turn such as a U-turn, the difference in rotation between the front and rear wheels is absorbed by the viscous coupling 13, and the tight corner braking phenomenon is prevented.

When the transmission torque of the viscous coupling 13 is increased, the driving force sent to the rear wheel side when the front wheel is idling is increased and the running performance is further improved. Also, when braking, the viscous coupling 13
If the transmission torque is reduced and the connection between the front and rear wheels is cut off, the interference of the braking force between the respective sides is prevented, and, for example, the lock on one side does not propagate to the other side and the ABS function is not hindered. As described above, the response of the characteristic adjustment is fast, so it is possible to quickly respond to sudden braking and protect the ABS function.

In the present invention, a pair of moving means is provided as the adjusting means, and the second plate is moved and operated on the one hand and the third plate is moved and operated on the other hand to adjust the distance between these and the first plate. May be. Further, the housing side may have a double plate structure.

[Advantages of the Invention] In the viscous coupling of the present invention, the plate on one transmission member side has a double plate configuration, and these plates are relatively moved in the axial direction by a slight stroke movement operation to move the plates on the other transmission member side. Since the plate distance from the plate can be adjusted, the characteristics can be adjusted quickly and the adjusting means can be downsized.

[Brief description of drawings]

1 (a) is a cross-sectional view of one embodiment, (b) and (c) are enlarged views of the essential parts of (a) at the minimum and maximum transmission torques of this embodiment, respectively, and FIG. 2 is a plan view of the plate. Fig. 3 and Fig. 3 are sectional views of the hub, and Figs. 4 (a) and 4 (b) are expanded sectional views showing the cross section of the bridge, and enlarged sectional views of essential parts showing minimum and maximum transmission torques, respectively. FIG. 3 is a skeleton mechanism diagram showing a power system of a vehicle using this embodiment. 23 ... Housing (first transmission member) 25 ... Hub (second transmission member) 45 ... Working chamber 55 ... First plate 59 ... Second plate 61 ... Third plate 87 ... ... Hydraulic actuator (adjustment means)

Claims (1)

[Claims] 1. A first and a second transmission member which are arranged so as to be rotatable relative to each other, a working chamber in which a viscous fluid is sealed, and a first rotation member which non-rotatably engages with the first transmission member in the working chamber. The first plate and the second and third plates arranged so as to sandwich the first plate and non-rotatably engaged with the second transmission member respectively, and the plate distance between the first plate and the first plate. A viscous coupling, comprising: an adjusting means for relatively moving the second and third plates in the axial direction via an operating force transmitting means for changing.