JPH038406B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention is a self-adjusting clutch comprising two parallel multi-plate clutches, one of which is a viscous clutch. The other multi-disc clutch is a friction clutch, with one inner and one outer clutch part arranged in a ring chamber formed by these two clutch parts so as to alternate between an inner clutch part and an outer clutch part. It consists of two sets of discs, each consisting of a number of discs connected to each other so that they cannot rotate relative to each other, one set of discs forming a viscous type clutch, and the other set of discs forming a friction clutch. The present invention relates to a viscous clutch of the type in which the inner and outer discs are each kept at an axial distance greater than the thickness of the discs arranged between them.

[Conventional technology]

A type of so-called viscous clutch is known in which friction clutches are arranged in parallel. In this case, the friction clutch takes charge of part of the torque transmission by compensating for the decrease in torque that occurs when the viscous clutch is heated. Its role is to return the viscous clutch to a lower temperature range (US Pat. No. 4,058,027).
The operation of a friction clutch is dependent on the effect of the temperature increase on the viscous clutch and the resulting pressure increase.
This is caused by acting on two differential pistons.

A disadvantage of self-adjusting clutches of this type is that the viscous clutch, which is primarily responsible for torque transmission, has a significantly temperature-dependent torque characteristic. That is, the operation of the friction clutch is simultaneously affected, resulting in an uncontrollable transmission ratio in the self-adjusting clutch.

Another difficulty lies in the following points. That is, the working chambers of the viscous clutch and the friction clutch are not separated from each other, so that both clutches must be loaded with the same fluid. As a result, it is not possible to provide the friction clutch with an optimum friction ratio.

Another difficulty is that the maximum torque cannot be clearly defined. This is because the maximum torque is dependent on the respective temperature of the viscous clutch.

[Problem to be solved by the invention]

SUMMARY OF THE INVENTION The object of the invention is to transmit a clearly defined maximum rated torque in an automatically operating adjusting clutch, which operates essentially independently of the transmission characteristics of the viscous clutch. In this case, the viscous clutch and the friction clutch can each be loaded with an optimal medium.

[Means to solve the problem]

The present invention has solved these problems as follows. That is, (a) the viscous clutch and the friction clutch are sealed and separated from each other by a single ring piston that is movable in the axial direction, and (b) the sliding stroke of the ring piston is caused by the friction. (c) at least one pressure plate arranged in front of the ring piston on the ring piston side of the friction clutch; Due to the spring arrangement, (d) the viscous clutch has a very small transmittable rated torque compared to a friction clutch.

〔Effect of the invention〕

The friction clutch of the present invention provides the following advantages. That is, the temperature-related uncontrollable torque characteristics of the viscous clutch do not lead to an uncontrollable transmission ratio, and the maximum transmittable torque of the self-adjusting clutch is achieved by the contact of the ring piston with the stopper on the friction clutch side. This means that it is restricted.

Even if a particular pressure buildup were to occur in the viscous clutch, no undesirably large torques would flow due to the ring piston hitting the stop.

According to one embodiment, a self-adjusting clutch is arranged in the drive path connecting the two axles to each other, in which case a torque transmittable by the self-adjusting clutch is transferred from the engine into the drive path. Very slightly more than the maximum torque introduced.

In this embodiment, the self-adjusting clutch automatically connects the second drive axle when a slip occurs in the main drive axle, and at the same time, the load in the drive path, i.e. when driving in a tight corner, automatically connects to the second drive axle. It makes it possible to avoid loads that are larger than the driving moment.

Such use of the self-adjusting clutch of the present invention provides an automatically engageable four-wheel drive system, which has the added advantage of not requiring front and rear differentials between the axles. enable.

According to another embodiment of the invention, a self-adjusting clutch is used as a differential brake.

In this embodiment, the self-adjusting clutch acts as a differential brake that will be applied when necessary;
In this case, too, tension forces between the drive axles or between the drive wheels that occur when driving around tight corners can be avoided.

By the way, as a hydraulic or fluid clutch,
A type is already known in which the transmittable torque is adjusted by changing the amount of working fluid (GB 414,662). In this case, the fluid volume is transferred from one or more working chambers to the reservoir chamber and thereby regulated until the clutch is completely released. The disadvantage of this known example is that the torque change occurs very slowly in response to the fluid movement and is therefore not suitable for all applications where a short or sudden change to the release position is required for safety reasons. Not suitable.

It is also known to operate differential locking devices via electromagnets (DE-A-2920107). However, this example also has the disadvantage that the magnetic field must be maintained during the effective period, and therefore a large amount of current is consumed. Moreover, with the friction clutch that produces the locking action, it is not possible to produce an automatic connection to a differential locking device or an additional drive axle.

Based on this recognition, the present invention is further characterized by the following points for the purpose of rapidly switching the self-adjusting clutch to its release position. (e) A ring flange is provided on the opposite side of the friction clutch from the ring piston; (f) the ring flange is supported by one or more springs; The spring force is made larger than the force of the compression spring belonging to the ring piston, and (g) the ring flange is caused by the magnetic field of one electromagnet to absorb the force of the spring located on the side opposite to the friction clutch side. (h) The amount of movement of the ring flange caused by the magnetic field is such that the ring piston is in contact with the stopper, especially when the action of the compression spring is completely nullified. This is how it is set.

According to such a configuration, the friction clutch that determines the driving torque is operated by the electromagnet, and as a result, the ring flange forming the bottom plate of the friction clutch moves in a direction away from the friction clutch.
This will result in an abrupt switching of the self-adjusting clutch to the released position.

Such a self-adjusting clutch arrangement is particularly advantageous when used for the purpose of automatically switching connection from one drive axle to another of a motor vehicle drive. In this case, the response of the clutch by actuation of the electromagnet can be triggered, for example, via the brake pedal. In such a case, when braking,
Multi-axis drive is eliminated, which makes it particularly
Difficulties that may arise in the case of motor vehicles equipped with locking devices are avoided.

In the case of an anti-lock device, the wheel of the drive wheel released via the electromagnet becomes the driven free-rotating wheel upon braking.

The principle of the self-adjusting clutch according to the invention also applies, for example, to differential locking systems in which the differential locking action is released by actuation of the brake pedal in order not to adversely affect the anti-locking system. be able to.

〔Example〕

FIG. 1 shows a self-adjusting clutch according to the invention in partial longitudinal section. The self-adjusting clutch essentially consists of an outer clutch part 1 and an inner clutch part 2 consisting of two parts. The inner clutch part 2 has a through hole 16 in which a spline 15 is formed. This inner clutch part 2 is axially fixed on a splined shaft from the transmission.
The outer clutch part 1 is provided with a connecting flange 14 to which a drive shaft (not shown) of the drive path can be fastened via a fixing hole 13.

A viscous type clutch 5 is located in the left half of the figure, and this viscous type clutch 5 consists of a number of disks 6 which are connected to each other in a manner such that the outer clutch part 1 and the inner clutch part 2 are connected in a manner that is not rotatable relative to each other. It consists of Between these disks 6, which belong to the outer clutch part 1 and the inner clutch part 2, respectively, a spacer 7, consisting of a wire ring, for example, is inserted.

Disc 6 has inner and outer axial position stops 18
axial movement is restricted by a and 18b.

A friction clutch 11 is shown in the right half of the figure. This friction clutch 11 also consists of a number of discs 12 which are connected alternately to an outer clutch part 1 and an inner clutch part 2 in a rotationally fixed manner.

Both the disk 6 of the viscous clutch 5 and the disk 12 of the friction clutch 11 have their respective clutch parts 1,
The relatively non-rotatable connection with 2 is effectively effected by a spline.

There is one pressure plate 10 inside the friction clutch 11.
is arranged, and this pressure plate 10 is also connected to the outer clutch part 1 in a relatively rotationally fixed manner. A ring piston 3 is arranged between the viscous clutch 5 and the friction clutch 11, and this ring piston 3 connects the working chambers of both the viscous clutch 5 and the friction clutch 11 to each other via a sealing ring 4. Separated. In this way, it is possible to fill the working chamber of the viscous clutch 5 and the working chamber of the friction clutch 11 with different liquids, and it is also possible to use a dry type friction clutch 11 instead of a wet type without any problem. I can do it.

Between the ring piston 3 and the pressure plate 10, a pressure spring 8 is arranged, which is arranged in a number of holes distributed evenly in the circumferential direction of the ring piston 3.
A protrusion 9 attached to the push spring 8 and attached to the ring piston 3
are provided, and these projections 9 push springs 8
It fits into the protrusion 19 of the pressure plate 10 along with a hole for the purpose. In this way, ring piston ring 3
The ring piston 3 is also connected in a relatively rotationally fixed manner to the outer clutch part 1 via the pressure plate 10, thus preventing any undesired rotation of the ring piston 3.

If a relative movement occurs between the two clutch parts 1, 2 due to a slip in the drive axle,
The discs 6 of the viscous clutch 5 will move relative to each other. In this case, the spacer 7 ensures that the discs 6 do not come into contact with each other.
The viscous clutch 5 thus also acts as a friction-free clutch. The shear forces acting on the viscous liquid filling the viscous clutch 5 cause heating of the viscous liquid, which is accompanied by a pressure acting on the ring piston 3 due to the increase in volume. This forces the ring piston 3 towards the friction clutch 11 and at the same time tensions the pressure spring 8. Via this pressure spring 8, the overpressure generated in the viscous clutch 5 is transmitted directly as a normal force to the friction clutch 11, which performs a torque transmission between the two clutch parts 1, 2.

The stop 17 makes it possible to adjust the maximum normal force on the friction clutch 11 in conjunction with the pressure spring 8.

The compression spring 8, which is shown as a helical spring in FIG. The possibility arises of operating the disk spring within the descending characteristic of the spring characteristic curve, so as to lead to. Of course, it is also possible to select a spring correspondingly with a substantially flat characteristic range near the top of the spring characteristic curve, which makes it possible to maintain a constant spring force within the wear range.

The length of the push spring 8 is such that there is no normal force acting on the friction clutch when the self-adjusting clutch is unloaded.

FIG. 2 shows a basic arrangement for the use of a self-adjusting clutch as an additional device in the longitudinal drive path of a motor vehicle. A front axle 22 is driven via an engine 20 and a transmission 21. As slip occurs in the wheels of the front axle 22, the self-adjusting clutch in the additional device 24 begins to transfer torque to the wheels of the rear axle 23 in the manner described above. This is because in this case a relative rotational speed occurs between the wheels of the front axle 22 and the wheels of the rear axle 23 due to slippage, which relative rotational speed causes the self-adjusting speed clutch to respond.

FIG. 3 shows a conventional differential gear device 26, by which both left and right wheels of one axle are driven via respective drive shafts 27.

A self-adjusting clutch is installed between the ring gear 25 and one of the driven gears in order to produce a braking action for the differential gear 26 in the event of slippage on one of the two wheels. This self-adjusting clutch ensures that its maximum transferable torque is transmitted to the other wheel even in the event of a slip in one wheel.

Another self-adjusting clutch of the present invention is shown in partial longitudinal section in FIG. The self-adjusting clutch primarily consists of an outer clutch section 101 and a two-part inner clutch section 102. The inner clutch portion 102 has a through hole 116 in which a spline 115 is formed. This inner clutch part 102 is axially fixed on a splined shaft from the transmission. The outer clutch part 101 is provided with a connecting flange 114 to which a drive shaft (not shown) of the drive path can be fastened via a fixing hole 113.

A viscous clutch 105 is located in the left half of the figure, and this viscous clutch 105 has an outer clutch portion 101 and an inner clutch portion 102.
It consists of a number of disks 106 which are alternately and rotationally connected to each other. Outer clutch part 10
1 and the inner clutch part 102, a spacer 107 is inserted, for example, consisting of a wire ring.

Disc 106 is restricted from axial movement by inner and outer axial detents 118a, 118b.

A friction clutch 111 is shown in the right half of the figure. This friction clutch 111 also has a number of discs 112 which are connected alternately and fixedly to the outer clutch part 101 and the inner clutch part 102.
It consists of

The rotationally fixed connection of both the disk 106 of the viscous clutch 105 and the disk 112 of the friction clutch 111 with the two clutch parts 101, 102 is effectively effected by means of splines.

There is one pressure plate 1 inside the friction clutch 111.
10 is arranged, and this pressure plate 110 is also connected to the outer clutch part 101 in a relatively rotationally fixed manner. A ring piston 103 is disposed between the viscous clutch 105 and the friction clutch 111.
1 are separated from each other via a sealing ring 104. In this way, the working chamber of the viscous clutch 105 and the friction clutch 111
It is possible to fill the working chamber with another liquid, and the friction clutch 111 can be made of a dry type instead of a wet type without any problem.

Between the ring piston 103 and the pressure plate 110, a pressure spring 10 is arranged in a number of holes uniformly distributed in the circumferential direction of the ring piston 103.
8 comes into play. A protrusion 109 is provided on the ring piston 103 attached to the push spring 108,
These projections 109 fit into the projections 119 of the pressure plate 110 together with the holes for the pressure springs 108.
In this way, the ring piston 103 is also connected in a rotationally fixed manner to the outer clutch part 101 via the pressure plate 110, so that an undesirable rotation of the ring piston 103 is prevented.

If a relative movement occurs between the two clutch parts 101, 102 due to slip in the drive axle, the disc 106 of the viscous clutch 105
will cause relative movement to each other. In this case, the spacer 117 ensures that the discs 106 do not come into contact with each other. Thus, the viscous clutch 105 also acts as a frictionless clutch. The shear forces acting on the viscous liquid filling the viscous clutch 105 cause heating of the viscous liquid, which heating is accompanied by pressure acting on the ring piston 103 due to its volume increase. This forces the ring piston 103 towards the friction clutch 111 and at the same time tensions the pressure spring 108. Via this pressure spring 108, the overpressure generated in the viscous clutch 105 is transmitted directly as a normal force to the friction clutch 111, which performs a torque transmission between the two clutch parts 101, 102.

The stop 117 allows the maximum normal force on the friction clutch 111 to be adjusted in conjunction with the push spring 108.

Pressure spring 1 shown as a coil spring in the figure
08 can of course also be a suitable disc spring, in which case the disc spring is operated within the descending characteristic of the spring characteristic curve, so that the wear of the friction disc of the friction clutch leads to a corresponding increase in the normal force. A possibility arises. Of course, it is also possible to select a spring correspondingly with a substantially flat characteristic range near the top of the spring characteristic curve, which makes it possible to maintain a constant spring force within the wear range.

The length of the push spring 108 is such that no normal force is applied to the friction clutch when the self-adjusting clutch is unloaded.

The following structural form and operational form are the same as in the example of FIG.

Ring piston 103 of friction clutch 111
A ring flange 128 is arranged on the opposite side, which itself rests on a spring 129 on the side opposite the friction clutch. This spring 129 is designed so that the force it exerts on the ring flange 128 is greater than the sum of the spring forces of the push springs 108. The ring flange 128 thus serves as a stationary housing limit wall for the friction clutch.

The spring 129 is connected to the stopper 131 via the insertion disk.
It is supported by an axial locking ring.

The ring flange 128 has a flange-like extension, which cooperates with an electromagnet 130 configured in the form of a ring. The housing of this electromagnet 130 is fixedly connected to the transmission housing 133, for example by screwing.

Upon actuation of electromagnet 130 by the voltage source, electromagnet 130 exerts a pulling force on the extension of ring flange 128, tending to pull ring flange 128 away from friction clutch 111 against the force of spring 129. The spring 129 may in this case be designed to work in a downward slope characteristic range in order to minimize its holding force against the electromagnet 130.

Ring flange 128 thus obtained
The amount of displacement is such that a normal force from the push spring 108 can no longer act on the friction clutch 111.

A clutch completely released by movement of the ring flange 128 no longer transmits torque, which means that if the vehicle is equipped with an anti-lock device, it will automatically connect to another drive axle. It has been found to be advantageous and necessary to do so. In this case, activation of the electromagnet 130 can be effected simply via a brake light switch.

In order to reliably prevent friction of the annular extension of the ring flange 128 on the electromagnet 130 during rotation of the clutch, it is necessary to limit the movement of the ring flange 128 itself by means of a stopper. This can be done by means of a stop 131, if the spring 129 is designed to lock the electromagnet 130 in the operative position.

[Brief explanation of the drawing]

Fig. 1 is a partial vertical sectional view of the self-adjusting clutch of the present invention, Fig. 2 is a layout diagram in the front and rear drive path of an automobile, Fig. 3 is a longitudinal sectional view of an example of use as a differential brake, and Fig. 4 is a partial longitudinal sectional view of the self-adjusting clutch of the present invention. FIG. 3 is a partial longitudinal sectional view of another self-adjusting clutch of the invention; 1,101...Outer clutch part, 2,102
...Inner clutch part, 3,103...Ring piston, 4,104...Seal ring, 5,10
5...Viscous type clutch, 6,106...Disc, 7,107...Spacer, 8,108...Press spring, 9,109...Protrusion, 10,110...
Pressure plate, 11, 111...Friction clutch, 12,
112... Disk, 13, 113... Fixing hole, 1
4,114... Connection flange, 15,115...
Spline, 16,116...Through hole, 17,1
17... Stoppa, 18a, 118a, 18b,
118b...Axial position stop, 19,119...
Projection, 20... Engine, 21... Transmission, 22...
...Front axle, 23...Rear axle, 24...Additional device,
25...Ring gear, 26...Differential gear device, 2
7... Drive shaft, 128... Ring flange, 12
9... Spring, 130... Electromagnet, 131... Stopper, 132... Drive pin, 133... Transmission casing.

Claims (1)

[Scope of Claims] 1. A self-adjusting clutch comprising two multi-plate clutches arranged in parallel, one of the multi-plate clutches forming a viscous clutch and the other multi-plate clutch forming a friction clutch, an inner and an outer clutch part and a plurality of inner and outer clutch parts arranged in a ring chamber formed by both clutch parts and connected alternately to the inner clutch part and to the outer clutch part in a relatively rotationally fixed manner, respectively. It consists of two disc sets consisting of discs,
One set of discs forms a viscous clutch and the other set of discs forms a friction clutch;
In a type of viscous clutch in which the inner disc and the outer disc are maintained at an axial distance greater than the thickness of the discs disposed between them, (a) the viscous clutch 5 and the friction clutch 11 are sealed and separated from each other by one ring piston 3 which is movable in the axial direction, and (b) the sliding stroke of the ring piston 3 is arranged on the side facing the friction clutch 11. (c) a ring piston 3 and a pressure plate 10 disposed in front of the ring piston side of the friction clutch 11;
(d) The viscous clutch 5 is arranged between the friction clutch 11 and the viscous clutch 5.
A self-adjusting clutch characterized in that it has an extremely small transmittable rated moment compared to. 2 A self-adjusting clutch connects the two axles 22, 23
The claimed invention is located in a drive path in which the self-adjusting clutch is arranged in a drive path in a transmission connection, and the torque transmittable by the self-adjusting clutch is very slightly in excess of the maximum torque introduced into the drive path from the engine. A self-adjusting clutch according to paragraph 1. 3. A self-adjusting clutch according to claim 1, wherein the self-adjusting clutch is used as a differential brake. 4. A self-adjusting clutch with two parallel multi-plate clutches, one of which is a viscous clutch and the other is a friction clutch, with one inner and one outer clutch. two clutch parts and a number of discs arranged in a ring chamber formed by both clutch parts and connected alternately to the inner clutch part and to the outer clutch part in a rotationally fixed manner, respectively. It is composed of a disk set,
One set of discs forms a viscous clutch and the other set of discs forms a friction clutch;
In a type of viscous clutch in which the inner disc and the outer disc are maintained at an axial distance greater than the thickness of the discs disposed between them, (a) the viscous clutch 105 is a friction clutch; 1
11 are sealed and separated from each other by a first ring piston 103 movable in the axial direction, and (b) the sliding stroke of the ring piston 103 faces its friction clutch 111. 1 placed on the side
(c) ring piston 103 and friction clutch 11
At least one pressure spring 108 is disposed between one pressure plate 110 disposed in front on the ring piston side of 1, and (d) the viscous clutch 105 is extremely small compared to the friction clutch 111. (e) The ring piston 10 of the friction clutch 111
3 has one ring flange 12 on the opposite side.
(f) The ring flange 128 is supported by one or more springs 129, the spring force of the spring 129 being greater than the force of the push spring 108 belonging to the ring piston 103. The (t)ring flange 128 is enlarged and the one electromagnet 13
(h) a ring flange 128 caused by the magnetic field; A self-adjusting clutch characterized in that the amount of movement of is set such that when the ring piston 103 contacts the stopper 117, the action of the push spring 108 is completely nullified.