Clutch

A friction clutch (1) with an inner ring (2) arranged about a rotary axis (d) and an outer ring (3) arranged coaxially in reference thereto, as well as an elastic intermediate ring (3) arranged between these two in a radially limited fashion, with the inner ring (2) and the intermediate ring (4) resting on each other via a ramp arrangement (9) arranged and acting bi-directionally in the circumferential direction. In order to embody the clutch (1) easily and cost-effectively, segments (13) pointing radially outwardly and arranged distributed over the perimeter form in connection with a radial displacement of the intermediate rings (4) relative to the outer ring (3) a positive connection (22) in the circumferential direction with the radial displacement of the intermediate ring (4) being provided with a ramp arrangement (12) effective in the axial direction and switched by an axial displacement of the inner ring (2) in reference to the intermediate ring (4).

INCORPORATION BY REFERENCE

The following documents are incorporated herein by reference as if fully set forth: German Patent Application No. 102015216366.0, filed Aug. 27, 2015.

BACKGROUND

The invention relates to a clutch with an inner ring, arranged about a rotary axis, and an outer ring, arranged coaxially thereabout, as well as an elastic intermediate ring arranged between them and radially limited.

Generic clutches are known for example from WO 2015/015320 A2. Here, an inner ring is received on gears of a shaft in a torque-proof fashion, and has an exterior perimeter embodied in the form of a traverse, on which a clamping ring is arranged having a complementary inner perimeter. An axially displaceable control ring is arranged radially between the clamping ring and an outer ring, having a ramp arrangement axially effective in reference to the outer ring. In an axial displacement of the control ring in the direction of the inclining ramp of the ramp arrangement a clamping connection develops between the clamping ring, the control ring, and the outer ring, which is released by an opposite displacement of the control ring.

SUMMARY

The objective of the invention is the advantageous further development of a generic clutch. In particular, the clutch is embodied for easy use and comprising as few components as possible.

The objective is attained with a clutch having one or more features of the invention. Advantageous embodiments are described below and in the claims.

The present clutch comprises an inner ring arranged about a rotary axis and an outer ring arranged coaxially in reference thereto, as well as an elastic intermediate ring arranged between them and radially limited. In the simplest case, the clutch can therefore be embodied from three parts. The inner ring and the intermediate ring rest on each other via a ramp arrangement, arranged in the circumferential direction and bi-directionally acting upon them. Here, a moment can be transmitted between the intermediate ring and the inner ring in both directions of rotation. Segments are provided at the intermediate ring, pointing radially outwardly and arranged distributed over the circumference, which in case of a radial pre-stressing of the intermediate ring form a positive engagement with the outer ring in the circumferential direction.

The positive engagement is switched in that a radial displacement of the intermediate ring provided via a ramp arrangement, acting in the axial direction, by an axial displacement of the inner ring switched in reference to the intermediate ring. This means that the ramp arrangement is provided in the form of axially inclining ramps at the inner ring and at the intermediate ring, particularly at its segments. By an inner ring, displaced from the outside, for example by an actuator, oil pressure of a device surrounded with a pressure medium, a displacement of the inner ring depending on torque, for example due to a diagonally geared part or the like, the intermediate ring is radially displaced towards the outside at the axially inclining ramps such that the segments form with the inner perimeter of the outer ring, provided with a radial profile, a detachable, moment-transmitting positive connection, so that the clutch is effective between the inner ring and the outer ring. When returning the inner ring, the clutch is opened again, with here by the radial return of the intermediate ring a gap opening between the segments and the outer ring. By locating the ramp arrangement directly between the inner ring and the intermediate ring here any additional components can be avoided.

Sufficiently wide cut-outs may be provided between the segments in order to generate radial elasticity for the intermediate ring. Furthermore, for example recesses may be provided dividing the segments radially from the inside and/or cut-in radially from the outside. Radially inward and radially outward recesses may be embodied and arranged radially over top of each other and forming braces with lower cross-sections in reference to the cross-section of the intermediate ring at the segments, which connect the segments at least radially in an elastic fashion. In this regard, the bars serve as elastic elements like springs. Alternatively or additionally the intermediate ring may be slotted at one side, thus embodied open at one side, so that a radial displacement of the intermediate ring is facilitated, while forming an enlarged diameter.

In case of an elastic embodiment of the connection between the intermediate ring and the inner ring the intermediate ring may be embodied rotational to a limited extent along the ramp arrangement with inclining ramps at both sides in the circumferential direction, so that it is displaced radially outwardly under the influence of a moment at least slightly in reference to the inner ring and thus it can generate a positive engagement of the intermediate ring with the outer ring.

In order to hold the intermediate ring at the inner ring and thus to avoid any contact with the outer ring when the clutch is open, the intermediate ring may be pre-stressed in reference to the inner ring.

In order to form the positive connection, the segments may have radially at the outside recesses or notches aligned radially inwardly, which are formed complementarily to the cams embodied at the outer ring radially inwardly, for example formed in one piece or fastened thereat.

According to an advantageous embodiment the clutch may be embodied in a stepped form, acting initially in a force-fitting, and then in a form-fitting fashion. Here, for example via a radial displacement of the segments a clamping connection may be formed via an axial displacement of the inner ring and subsequently the form-fitting connection can be generated by the cams of the outer ring sliding into the recesses of the intermediate ring.

It is understood that in the inverse embodiment, in order to form the positive connection, the cams can be provided at the intermediate ring and complementary to the cams, at the inner circumference of the outer ring, radially outwardly inserted, for example embossed pockets may be provided.

According to an advantageous embodiment the clutch includes a friction clutch, in addition to the switchable, detachable connection, radially inside the inner ring. The friction clutch is for example embodied as a wet-running friction clutch, which has an input part and an output part, with blades being allocated to the input part and the output part, respectively alternating laminated, with the blades under pressure forming a friction-fitting connection.

According to an advantageous embodiment the inner ring may form a blade carrier for the blades of the input or the output part. For this purpose, an inner profile like inner gears is provided at the input part, with the blades being suspended therein in a torque-proof fashion. The outer profiling with the bi-directional ramps embodied in the circumferential direction and the inner profile can be embodied during the production of the inner ring, waiving any additional tools.

In other words, a particularly easily produced clutch without any classic gears is suggested. The blocking between the inner ring and the outer ring is preferably performed by a positive connection in the radial direction. This allows a simple and cost-effective production as well as low stress. Simple production can be ensured by the use of sheet-metal parts.

Furthermore, a single-track method, such as synchronization according to gears, is not necessary, here.

The invention may have the following advantageous features with this list not being conclusive.Activating the clutch via an axial displacement of the inner ring and radial expansion of the intermediate ring (wedge plate),Ramps at both sides between the intermediate ring and the inner ring allocated in the circumferential direction (push and pull-operation),Axial ramp arrangement in order to generate a clamping contact at the outer diameter of the intermediate ring and a groove of the outer ring,Positive connection between the intermediate ring and the outer ring,In the deactivated state, no contact between the intermediate ring and the outer ring,The intermediate ring is radially pre-stressed on the inner ramps of the inner ring.

The inner ring may have at the inner diameter a gearing for the inner blades of a wet-running clutch. Furthermore, bi-directional ramps are provided at the inner ring for the pull and push-operation of the clutch, mounted at the outer perimeter of the inner ring in the circumferential direction. Furthermore, the outer diameter of the inner ring has an incline in the axial direction. This incline is preferably greater than the switching limit of the positive connection between the intermediate ring and the outer ring.

The intermediate ring shows at the inner circumference bi-directional ramps in the circumferential direction for the push and pull-operation. Furthermore, here an incline is provided in the axial direction at the segments, complementary to the incline of the inner ring. A positive contact is given at the outer diameter in reference to the outer ring, for example via cams of the outer ring distributed over the perimeter and expanded radially inwardly.

The outer ring may be equipped with a profile at the inner perimeter, acting radially inwardly. A form-fitting connection may be provided at the outer perimeter, for example gears to connect the outer ring with a housing or the like.

In the non-switched state of the clutch, the intermediate ring is placed in a pre-stressed state on the inner ring and has with its outer perimeter no contact to the outer ring and/or its profile. The pre-stressing is facilitated by dividing the intermediate ring.

In order to shift the clutch, the inner ring is axially displaced so that the intermediate ring widens and generates a contact to the outer ring. By this contact a positive connection develops, which is embodied by a radial displacement of the segments via a gliding process of the intermediate ring along the ramps at the inner ring with another enlargement of the diameter of the intermediate ring and thus leads to a form-fitting connection between the inner ring and the outer ring. Now the clutch is closed.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1shows the clutch1arranged about the rotary axis b in a front view. The clutch1comprises the inner ring2and the outer ring3as well as the intermediate ring4arranged therebetween. The inner ring2has at its inner perimeter5the inner gears6for receiving blades of a wet-running friction clutch. In this regard, the inner ring serves as the blade carrier like the outer blade carrier.

The inner ring2comprises at its outer perimeter inclining ramps7,8, arranged distributed over the circumference and alternating in both circumferential directions, at which ramps10,11are received, forming the ramp arrangement9of the intermediate ring4via ramps7,8embodied complementarily thereto. In a manner not shown, additionally a ramp arrangement12with axial ramps is arranged, shown inFIG. 2, between the inner ring2and the intermediate ring4.

The intermediate ring4has segments13, arranged widened radially outwardly and distributed over the circumference, which are separated from each other via recesses14,15,16entered radially from the inside and radially from the outside, and thus allow a radial displacement of the intermediate ring4while widening the recesses14,15,16. Here, the bars19between the segments13serve as elastic elements. Additionally, the intermediate ring4is opened unilaterally via the penetration17. The intermediate ring4is received on the inner ring2, radially pre-stressed. Depending on the switching state of the clutch1, the segments13come into a positive contact with the inner perimeter18of the outer ring3.

The outer ring3can be connected in a manner not shown at its outer perimeter to a housing or the like in a form-fitting or friction-fitting fashion, or by material-to-material bonding.

In order to form the active positive connection22shown here the cams20arranged distributed over the perimeter at the outer ring3engage radially the recesses21in the segments13.

FIG. 2shows the clutch1ofFIG. 1in a cross-sectional detail with the inner ring2, the outer ring3, and the intermediate ring4.FIG. 2illustrates the embodiment of the ramp arrangement12. The ramps7,8of the inner ring2and the ramps10,11of the intermediate ring4and/or the segments13complementary thereto are embodied as axially inclined ramps. The cams20engage the recesses21of the segments13to generate the positive connection22.

Based on the combined analysis ofFIGS. 1 and 2the function of the clutch1is explained. When the clutch1is opened, the intermediate ring4is radially pre-stressed on the inner ring2without any displacement of the ramps7,8,10,11in reference to each other. This way a radial gap forms between the segments13and the outer ring3and/or the cams20, so that no moment is transmitted.

In order to actuate the clutch, the inner ring2is displaced in reference to the outer ring3axially for example via an actuator, a pressure piston, or the like. This way via the ramp arrangement12, the segments13are displaced radially outwardly at the ramps7,8,10,11such that the segments13engage the cams20in a friction-fitting fashion. By the different rotation of the inner ring2and the outer ring3the intermediate ring4is delayed or accelerated in reference to the inner ring causing a relative rotation of the ramp arrangement9with the inclines of the ramps7,8,10,11arranged in the circumferential direction and thus a relative rotation of the intermediate ring4in reference to the inner ring2. This way, the segments13are further distorted in reference to the cams20until the cams20latch radially pre-stressed in the recesses21.

In order to again open the clutch1the inner ring2is displaced in the opposite direction of the axial inclines of the ramps7,8,10,11. This way, the pre-stressing of the segments13is reduced in reference to the cams20and the intermediate ring4rotates under its pre-stressing force on the inner ring2and under releasing of the positive connection22between the cams and the recesses21into its original position, so that the force-fitting connection of the segments13at the outer ring3is released again.

LIST OF REFERENCE CHARACTERS