WO2020259747A1

WO2020259747A1 - Coupling element for a switchable freewheel having an omega spring and switchable freewheel having a coupling element

Info

Publication number: WO2020259747A1
Application number: PCT/DE2020/100473
Authority: WO
Inventors: Christian Hartmann
Original assignee: Schaeffler Technologies AG & Co. KG
Priority date: 2019-06-28
Filing date: 2020-06-05
Publication date: 2020-12-30
Also published as: DE102019117528B3

Abstract

The invention relates to a coupling element (5) for a switchable freewheel (1), having a cage (14) in which an omega spring (6) is received in an interlocking manner, wherein in a first operating state, the omega spring (6) is operatively connected to a further component (15) surrounding the cage (14) and in a second operating state, the omega spring (6) is separated from the further component (15), wherein the omega spring is moved from the first operating state to the second operating state by means of a deformation. The invention further relates to a switchable freewheel (1) having an outer ring (15), an inner ring (16) which can be rotated relative to the outer ring (15), and a cage (14) which is arranged between the outer ring (15) and the inner ring (16), and having such a coupling element (5) and an actuation element (2) which can enter into operative connection with the coupling element (5) and can transfer the coupling element (5) from the first operating state to the second operating state.

Description

Clutch element for a switchable freewheel with an omega spring and switchable freewheel with a clutch element

The invention relates to a coupling element for a switchable freewheel, a switchable freewheel with such a coupling element and an omega spring.

Freewheels are used for power transmission in a drive train when a drive torque is to be transmitted in a first direction of rotation, but decoupling from the driven part of the drive train is to be made possible when rotating against the first direction of rotation in order to avoid a rigid hub connection. Thus, in particular, the friction in the drive train can be reduced, since in the freewheeling mode there is a decoupling of the

Drive machine can take place from the output shaft and the drive machine and the rigidly connected element do not have to be dragged through the drive train.

From DE 10 2012 217 927 A1 a freewheel with a drive element and an output element is known, a cage being arranged between the drive element and the output element. In the cage, clamping rollers and spring elements are provided which spring the clamping rollers against clamping ramps, with a torque being transferable from the drive element to the output element in a load rotation direction, while a free-wheel function is enabled in a free-wheel rotation direction. In this case, an intermediate ring having the clamping ramps and radially displaceable ring segments is provided between the drive element and the output element, which create a frictional connection with the output element in the load rotation direction.

In US 50 36939 A an all terrain vehicle is described, in the steered

Front wheels are integrated with freewheels. Through the respective freewheel can

Speed differences or slip between the wheels are compensated. DE 11 2014 005 508 T5 discloses a wedge coupling with an inner and an outer hub. The wedge coupling includes a wedge element that includes individual circumferentially distributed segments that are disposed radially between the first and outer hubs. The wedge coupling further comprises an outer ring and a first and a second displacement element. The ring is arranged radially between the wedge element and the outer hub and is non-rotatably connected to the segments. The ring presses the segments radially inwards until they make contact with the inner hub. For a closed mode, press the first

Displacement element, the wedge element in a first axial direction, which is parallel to an axis of rotation of the wedge coupling, in order to connect the inner and outer hubs, the wedge element and the outer ring to one another in a rotationally fixed manner. For an open mode, the second displacement member translates the wedge member in a second axial direction, which is opposite to the first axial direction, to allow relative rotation between the inner and outer hubs.

DE 1530676 A discloses a drive train of a motor vehicle with two driven axles. The drive of one axis is switchable by means of a

Overrunning clutch can be switched on and off. The overrunning clutch has a roller cage and a number of pinch rollers. The inner part of the freewheel is with

Provide clamping surfaces with a ramp contour. The cage is left and right beyond the freewheel and is rotatably supported to one side. On the same side, a leaf spring is arranged, which the cage with the pinch rollers in a

Free-running position leads or holds it there. For this purpose, the leaf spring is designed to be almost curved in a semicircle. In the installed position, it has spring ends at the top and bottom of the bend which are angled radially from the bend and which each engage in a bore, with which the leaf spring is held in the installed position. The cage is extended to another side with a friction surface that runs in a chamber with a viscous liquid. The resistance of this fluid is set in such a way that the cage can overcome the resistance of the leaf spring from certain differential speeds between the coupling halves and the freewheel engages in a switching position.

The one-way clutch published with DE 18 11 454 A, which is used for the feed and

Switching off a vehicle axle is provided, is based on a similar basic structure as that of the freewheel described with DE 1530676 A. In this case are Instead of the leaf spring, however, tangentially aligned helical compression springs distributed around the circumference are used, with which the freewheel is held in the freewheeling position.

The object of the invention is to propose a coupling element for a switchable freewheel, which is actuated by a small axial force and thereby produces a radial frictional contact between the outer ring and the cage in order to achieve a

To transmit torque from the outer ring to the cage.

According to the invention, this object is achieved by a coupling element for a switchable freewheel with a cage in which an omega spring is positively received, the omega spring being in operative connection in a first operating state with a component surrounding the cage and in a second operating state from the further component is separated, the omega-spring being transferred from the first operating state to the second operating state by deformation. In this context, an omega spring is one

To understand sheet metal spring, which is bent in the form of the Greek letter Omega. One advantage of the proposed coupling element is that the radial preload of the

Coupling element can be interrupted. In addition, the spring characteristics of an omega spring can be set more easily and more reproducibly than with a corrugated spring or a helical spring. Another benefit is that when active

Actuation no power loss is generated, since the omega spring at a

Activation is completely separated from the component surrounding the omega spring. In this way, the frictional losses during power interruption can be prevented. Furthermore, the space used for this spring is less than that of a wave spring or a helical spring.

The features listed in the dependent claims are advantageous improvements and further developments of the in the independent claim

specified coupling element possible. In a preferred embodiment of the invention it is provided that a friction surface is formed on an outside of the omega spring, the

Friction surface is pressed against a component surrounding the cage, so that a non-positive connection is established between the cage and the component. A friction surface can be used in a simple and easily reproducible manner

Frictional connection between the omega spring of the coupling element and the surrounding component can be established. It is preferred if the

Friction surface has a convex shape. Due to the convex shape, the

The spring tolerances can be selected to be relatively large, since the friction surface can compensate for contact errors on the component surrounding the omega spring.

In an advantageous embodiment of the invention, it is provided that legs are formed on the omega spring, in which an actuation pin can engage in such a way that the fleas of the omega spring is reduced by elastic deformation. Among the fleas the omega feather in this context is the

Understand the extension of the spring from the bearing surfaces to the friction surface.

A reversible, elastic deformation of the omega spring can be controlled in a simple manner by means of the legs. A separation of the friction surface of the omega spring from the component surrounding the omega spring can thus be achieved in a functionally reliable manner. In an advantageous further development, the force with which the friction surface of the omega spring is pressed against the component surrounding the omega spring can also be varied in order to make the coupling process even smoother.

In a further improvement of the invention it is provided that the omega-spring has convex bearing surfaces on each of its end sections, which rest against a base of the recess in the cage. The convex bearing surfaces can compensate for tolerances on the base surface of the recess of the cage, and a convex bearing surface enables elastic deformation with comparatively little effort, which makes it easier to separate the friction surface from the component surrounding the omega spring in the radial direction. According to the invention, a switchable freewheel with an outer ring, an inner ring that can be rotated relative to the outer ring and a cage is proposed, which is arranged between the outer ring and the inner ring. The switchable freewheel further comprises a coupling element according to the invention and a

Actuating element which can come into operative connection with the coupling element and which can transfer the coupling element from the first operating state to the second operating state. With such a freewheel, a switchover between a freewheel function and a clamping function can take place in a simple manner. The cage can by a speed difference between the

Outer ring and the inner ring are dragged through the outer ring, in such a way that clamping bodies, in particular pinch rollers, guided in the cage are brought into a locking position and prevent rotation between the outer ring and the inner ring. Due to the separation between the coupling element and the outer ring, this locking position can be easily canceled, since there is no frictional engagement between the cage and the outer ring and the cage is turned back into its starting position by simple means, in particular by return springs which the freewheel function is guaranteed.

In a preferred embodiment of the switchable freewheel it is provided that actuation pins are formed on the actuating element, which come into operative connection with the omega spring in the event of an axial displacement and cause the omega spring to deform, such that a friction surface of the omega spring of an inner surface of the outer ring is separated and a gap is created between the friction surface and the outer ring. Actuation pins enable simple and

A reversible, elastic deformation of the omega springs can be controlled in a material-friendly manner, with the contact being released from a certain distance

Friction surfaces of the omega springs from the inside of the outer ring so that the cage can rotate freely. The ramp contour allows tolerances on the legs of the omega springs to be compensated for, so that with a complete

Pushing in the actuation pins ensures that the friction surfaces detach from the inside of the outer ring and that a gap is created. In a further improvement of the invention it is provided that the actuation pins are conical or have a ramp contour which engages in the legs of the omega spring. By conical design of the actuation pins, a defined deformation of the legs of the omega springs can also be achieved, whereby a targeted reversible, elastic deformation of the omega springs is achieved.

In an advantageous embodiment of the invention, it is provided that the actuation element comprises an activation ring, the actuation pins being molded or formed on the activation ring. By means of an activation ring with activation pins molded onto the activation ring, a plurality of activation pins can be controlled in a simple manner with only one linear actuator. In addition, such an actuation ring can be manufactured simply and inexpensively as an injection-molded part, as a result of which the costs for a switchable freewheel can be reduced.

It is preferred if between the activation ring and the cage

Return springs are arranged, which upon activation of the

Actuating element are compressed and push the activation ring back into its starting position after activation has ended. By

Return springs, a return force can be generated in a simple manner, which pushes the activation ring back into its starting position after the activation via the actuator has ended. A further actuator or a complex actuator can therefore be dispensed with, which means that the costs for the switchable freewheel can be reduced.

It is particularly preferred if the return springs are designed as spiral springs, with spring domes formed on the cage and / or on the activation ring, on which the return springs are positively received. By means of spring domes on the activation ring and / or the cage, springs can be received in a form-fitting manner in a simple and inexpensive manner. This prevents the return springs from slipping. Thus, the restoring force can be targeted the activation ring are exercised, whereby tilting or jamming of the activation ring is avoided.

The invention also relates to an omega spring with a tensioning element for

reversible, elastic deformation of the omega spring for use in a motor vehicle component with at least one rotating component, in particular in a switchable freewheel, wherein the clamping element can come into operative connection with the legs of the omega spring via a frictional connection, you being a

Pushing the clamping element into the omega spring causes a defined reversible, elastic deformation of the omega spring. A deformation of the omega spring can thus be achieved in a simple manner in order to bring the omega spring, in particular the friction surface of the omega spring, into contact with another component and to control the forces which can be transmitted by means of frictional engagement.

In a preferred embodiment of the omega spring it is provided that the legs of the omega spring form a ramp contour for the tensioning element on which the tensioning element is received in a frictionally engaged manner in order to exert a defined expanding force on the omega spring. This allows a defined

Deformation of the omega spring can be achieved with tight shape and position tolerances. The ramp contour is dependent on the insertion path of the

Clamping element a defined introduction of force possible, whereby a targeted

Deformation of the omega spring is achieved and the degree of deformation is much more accurate than with a helical spring. In addition, the frictional engagement between the tensioning element and the legs of the omega spring is improved by the ramp contour, which means that higher forces can be used for deformation or the degree of deformation can be controlled in a targeted and repeatable manner.

The various embodiments of the invention mentioned in this application are, unless stated otherwise in the individual case, advantageously with one another

combinable. The invention is explained below on the basis of preferred embodiments with reference to the attached figures. The same components or components with the same function are identified with the same reference symbols. Show:

1 shows an embodiment of a coupling element according to the invention and an actuator for actuating such a coupling element; and

Fig. 2 shows an omega spring and an actuation pin for deforming the

Omega spring.

In Fig. 1, an embodiment of a coupling element 5 according to the invention for a switchable freewheel 1 is shown. The coupling element 5 comprises an omega spring 6, which is positively received in a recess of a cage 14. The omega spring 6 is surrounded in the radial direction by an outer ring 15 of the switchable freewheel 1. A friction surface 8 of the Omega spring rests against the inside of the outer ring 15 in an unloaded initial state of the coupling element 5. The omega spring 6 has two legs 7 into which an actuation pin 3 with a ramp contour 4 can penetrate and control a deformation of the omega spring 6. The omega spring 6 also has a convex bearing surface 11 in each of its end sections 9, 10 which rests on a base of the recess of the cage 14. By inserting the

Actuation pins 3, the ramp contours 4 come into contact with the legs 7 of the omega spring 6, the omega spring 6 being compressed in the radial direction so that the fleas of the omega spring 6, i.e. the expansion between the convex bearing surfaces 11 up to the Friction surface 8, reduced. A gap 17 is thus created between the friction surface 8 and the outer ring 15.

Furthermore, a switchable freewheel 1 with an actuator for actuating such a coupling element 5 is shown in a sectional illustration in FIG. The switchable freewheel 1 comprises an outer ring 15 and one relative to the outer ring 15 rotatable inner ring 16 and a cage 14 which is arranged in the radial direction between the outer ring 15 and the inner ring 16. The switchable freewheel 1 also comprises a coupling element 5 and an actuating element 2, which can come into operative connection with the coupling element 5. The

Actuating element 2 comprises an activation ring 12, on which actuation pins 3 protruding in the axial direction from the annular basic shape in the direction of the cage 14 are formed. Furthermore, spring domes are formed on the activation ring 12, on which return springs 13 are received. By a

The actuating element 2 is controlled in the axial direction with a

Actuating force FA shifted in the direction of the cage 14. The

Return springs 13 are compressed and the actuation pins 3 are pushed into the legs 7 of the omega springs 6. By activation, the omega springs 6 are transferred from a first operating state, in which the omega springs are in contact with an inner surface of the outer ring 15 and a torque can be transmitted, into a second operating state, in which a gap 17 between the friction surfaces 8 and the outer ring 15 is created and the cage 14 is free of contact with the outer ring 15. Thus, when there is a speed difference between the outer ring 15 and the inner ring 16, the cage 14 is not dragged along via the omega springs 6 and can rotate freely.

In Fig. 2, an omega spring 6 of a coupling element 5 according to the invention is shown in a three-dimensional representation. The omega spring 6 has a friction surface 8 on its radially outer side. The omega spring 6 also has two legs 7 which are formed by the flanks of the omega spring 6. The omega spring 6 also has two end sections 9, 10 which have a convex shape, as a result of which the omega spring 6 can compensate for shape and positional tolerances. Furthermore, due to the convex shape of the end sections 9, 10, the spring travel can be increased.

Furthermore, a section of an activation ring 12 is shown in FIG. 2, onto which an activation pin 3 which runs out in a ramp-shaped manner from the activation ring is formed. Preferably, several actuation pins 3 are evenly spaced over the circumference of the Activation ring 12 distributed, each of the actuation pins 3 engaging in the legs 7 of an omega spring 6.

When the clutch element 5 is not actuated, the friction surfaces 8 of the Omega springs 6 rest against an inside of the outer ring 15. Thus, the cage 14, in which the omega springs 6 are positively received, is dragged along by the outer ring 15 by means of a frictional connection. This leads to a rotation of the cage 14 relative to the inner ring, as a result of which a locking effect can be achieved.

By actuating an actuator, the actuating element 2 becomes axial

postponed. As a result, via the actuation pins 3 with the ramp contours 4, pressure is exerted on the insides of the legs 7 on the omega springs 6 of the

Coupling element 5 exercised. The legs 7 are pressed together in the direction of the cage 14 and the radial force between the friction surfaces 8 and the outer ring 15 is released. The coupling element 5 is no longer in contact with the outer ring 15 and torque is no longer transmitted from the outer ring 15 to the coupling element 5 or from the coupling element 5 to the outer ring 15. It is advantageous here that the radial pretensioning force of the coupling element 5 can be interrupted via an axial actuation of the actuator. A further advantage results from the fact that no power loss is generated during active actuation, since the coupling elements 5 are completely separated from the outer ring 15 by the gap 17.

If the actuation of the actuator is terminated, the actuating element 2 is moved back into its starting position in the axial direction by the return springs 13. As a result, the ramp contours 4 of the actuation pins 3 are pulled out of the legs 7 of the omega springs 6, the omega springs 6 expanding again in the radial direction and coming into contact with the inner surface of the outer ring 15. Thus, the coupling element 5 is again frictionally engaged with the

Outer ring 15 in contact and a torque can be transmitted from the outer ring 15 to the cage 14 or from the cage 14 to the outer ring 15. If the actuator is not actuated, the coupling element 5 is in permanent contact with the Outer ring 15. A torque can be transmitted from outer ring 15 to cage 14 or the other way around in both directions of rotation.

Reference list

Switchable freewheel

Actuator

Actuation pin

Ramp contour

Coupling element

Omega spring

leg

Friction surface

first end section

second end section

convex contact surface

Activation ring

Return spring

Cage

Outer ring

Inner ring

gap

Claims

1. Coupling element (5) for a switchable freewheel (1), with a cage (14) in which an omega spring (6) is positively received, the omega spring (6) in a first operating state with a cage ( 14) surrounding further component (15) is in operative connection and is separated from the further component (15) in a second operating state, the Omega spring being converted from the first operating state to the second operating state by deformation.

2. Coupling element (5) according to claim 1, characterized in that a friction surface (8) is formed on an outside of the omega-spring (6), the friction surface (8) against a component (15) surrounding the cage (14) is pressed so that a positive connection between the cage (14) and the component (15) is established.

3. Coupling element (5) according to claim 1 or 2, characterized in that legs (7) are formed on the omega spring (6), in which a

Actuating pin (3) can intervene in such a way that the fleas of the omega spring (6) is reduced by elastic deformation.

4. Coupling element (5) according to one of claims 1 to 3, characterized

characterized in that the omega spring (6) has at its end sections (9, 10) in each case convex bearing surfaces (11) which bear against a base of the recess in the cage (14).

5. Switchable freewheel (1) with an outer ring (15), an inner ring (16) which can be rotated relative to the outer ring (15) and a cage (14) which is arranged between the outer ring (15) and the inner ring (16), and with a

Coupling element (5) according to one of claims 1 to 4 and one

Actuating element (2), which with the coupling element (5) in Can enter an operative connection and the coupling element (5) can transfer from the first operating state to the second operating state.

6. Switchable freewheel (1) according to claim 5, characterized in that actuation pins (3) are formed on the actuating element (2), which come into operative connection with the omega spring (6) during an axial displacement and deformation of the omega Spring (6) cause such that a

Friction surface (8) of the omega spring (6) is separated from an inner surface of the outer ring (15) and a gap (17) between the friction surface (8) and the

Outer ring (15) arises.

7. Switchable freewheel (1) according to claim 6, characterized in that the actuation pins (3) are conical or have a ramp contour (4) which engage in the legs (7) of the omega spring (6).

8. Switchable freewheel (1) according to one of claims 5 to 7, characterized

characterized in that the actuation element (2) comprises an activation ring (12), the actuation pins (3) being molded onto the activation ring (12).

9. Switchable freewheel (1) according to claim 8, characterized in that

Return springs (13) are arranged between the activation ring (12) and the cage (14), which are compressed when the actuating element (2) is activated and push the activation ring (12) back into its starting position after activation has ended.

10. Switchable freewheel (1) according to claim 9, characterized in that the return springs (13) are designed as spiral springs, with spring domes being formed on the cage (14) and / or on the activation ring (12) on which the return springs ( 13) are positively received.

11. Omega spring (6) with a tensioning element (2, 3) for reversible, elastic deformation of the omega spring (6) for use in a

Motor vehicle component with at least one rotating component, in particular in a switchable freewheel (1), the tensioning element (2, 3) with the legs (7) of the omega spring (6) via a frictional connection in

Can come into operative connection, with an insertion of the tensioning element (2, 3) into the omega spring (6) causes a defined reversible, elastic deformation of the omega spring (6).

12. Omega spring (6) according to claim 11, characterized in that the

Legs (7) of the omega spring (6) form a ramp contour for the tensioning element (2, 3) on which the tensioning element (2, 3) is frictionally engaged

is added to exert a defined spreading force on the omega spring (6).