WO2006114265A1

WO2006114265A1 - Actuator

Info

Publication number: WO2006114265A1
Application number: PCT/EP2006/003769
Authority: WO
Inventors: Ulrich Grau; Harald Hochmuth; Günter Hartig; Jürgen OSTERLÄNGER; Dieter Adler; Manfred Kraus
Original assignee: Schaeffler Kg
Priority date: 2005-04-28
Filing date: 2006-04-25
Publication date: 2006-11-02

Abstract

Am actuator (5) comprises a motor (9a) and a driven portion (7) for connecting it to a positioning device (8a), a locking mechanism (19a) being provided for blocking the driven portion (7) when the driving force transmitted from the actuator (5) to the driven portion (7) is smaller than an outer force acting upon the driven portion (7).

Description

actuator

The present invention relates to an actuator. Actuators have a motor and a driven part which is connected to an actuator. The output member may be formed translational or rotary acting. Actuators are used for example in motor vehicles in the chassis. For example, in the case of a wheel suspension, an actuator can be assigned to the individual wheels, which can be controlled independently and carries out the desired adjustment of the body-side adjusting element of the wheel guide element. These actuators can be supported on the vehicle body.

From DE 100 11 142 A1, for example, a wheel suspension for motor vehicles has become known, in which a trained as a handlebar or actuator wheel guide a suspension of a motor vehicle is connected at one end to a wheel, and is hinged at its second end by an actuator. This actuator comprises an electric motor and a ball screw whose threaded spindle is designed as a driven member, that the wheel guide member articulates via a rotary joint. Such actuators assume safety-related functions. In such applications of actuators there is the requirement that the hinged chassis parts, for example, in case of failure of the actuator perform no unwanted positioning movements, but are kept in the last set position. Likewise, it should be ensured that external forces, which are introduced via the chassis into the actuator backwards, be safely collected without the actuator performs unwanted positioning movements due to these external forces.

Object of the present invention is to provide an actuator according to the features of the preamble of claim 1, in which these requirements are met. According to the invention, this object is achieved by that a locking mechanism is provided. in that the output member blocks when the driving force of the actuator on the output member is smaller than an external force acting on the output member. The locking mechanism are preferably designed to be switchable. If, for example, an actuator according to the invention is used for the active adjustment of the camber of a wheel of a motor vehicle, for example, impacts introduced from the outside into the wheel are only forwarded to the output part of the actuator. Introducing these impact forces in the actuator to the engine is excluded, since the output member is blocked by the locking mechanism according to the invention. These impact forces can be introduced via the locking mechanism in a support member, wherein in an application in motor vehicles, the support member may be supported in the effective directions of the external force on a frame part.

The motor shaft of the motor can be connected to a rotatable drive part of a transmission, wherein the transmission converts a rotation of the drive part into a translation or a rotation of the output part of the transmission. In this case, it may be appropriate to effectively arrange the locking mechanism between the drive part of the transmission and a support member fixed to the frame, for example. The locking then connects in its blocking position, the rotatable drive member rotatably with this support member. In its release position, the locking mechanism releases a relative rotation between the rotatable drive part and the support part. This means that, when the active adjustment is carried out without interference, the output part actuated by the actuator can be operated in a translatory or rotational manner, for example to change the camber. Once, for example, potholes in the road impact forces in the wheel and the wheel are finally introduced to the output part, which are greater than the actuating forces generated by the actuator or driving forces on the output part, the locking mechanism automatically switches to its blocking position. This means that such impact forces can not be introduced to the motor of the actuator in order to adjust it in an undesirable manner. Should the actuator fail, for example because the engine has failed, no forces generated by the actuator will be effective on the stripping section. In this Case switches the ratchet automatically at each acting on the driven part external force in its blocking position.

The invention may be formed by an actuator having a motor and a ball screw. The trained as Abtreibsteil threaded spindle of the ball screw is then connected to an actuator, and the spindle nut of the ball screw can be driven by the motor. The adjusting element may be a lever arm whose adjustment, for example, changes the camber.

In these actuators according to the invention, a switchable locking mechanism between the drive part, such as the spindle nut and a support member can be effectively arranged, the locking mechanism blocks the drive part in its blocking position relative to the support member and releases in its release position a relative rotation between the drive member and the support member.

Such switchable locking mechanism have become known, for example from DE 44 47 480 A1 as Klemmrollengesperre. In the same way as in the function of the mechanism provided according to the invention as described above, it is also provided for the use of this switchable clamping roller locking mechanism that, in its blocking position, a drive torque transmitted to the drive part by the motor is smaller than an external torque transmitted to the drive part is generated due to an external force acting on the drive part, wherein in the release position, the drive torque of the actuator is greater than the external torque.

This switchable Klemmrollengesperre may have a provided with clamping ramps clamping ring and a hollow cylindrical part with a cylindrical clamping track, which forms together with the clamping ramps wedge-shaped clamping gaps, in which clamping rollers are arranged, which are switchable with the clamping gaps in and out of clamping engagement. In such switchable Klemmrollengesperren the roles are in constant clamping standby. For this purpose, the clamps can be spring-loaded by means of springs into the wedge-shaped tapering clamping gaps, so that the clamping rollers abut, on the one hand, the cylindrical clamping track and, on the other hand, the clamping ramps. Usually, a plurality of wedge-shaped clamping gaps distributed in the circumferential direction are provided, which taper in opposite directions. A relative rotation of the clamping ring relative to the hollow cylindrical part is excluded in this arrangement. In order to enable a relative rotation, a switching part may be provided, which is provided with buttons for unlocking the Klemmrol- len. Unlocked pinch rollers are not in clamping readiness with the clamping ramps and the cylindrical clamping track.

A development of the invention provides that the motor shaft of the motor is rotatably connected to a switching part, which is provided with buttons for unlocking the pinch rollers and with a driver for positive entrainment of the clamping ring. The clamping ring may be rotatably connected to the drive part, but also integrally formed therewith. Furthermore, the clamping ring can be arranged coaxially in the hollow cylindrical part, wherein this hollow cylindrical part is rotatably connected to the support member. When the actuator is actuated, the motor shaft rotates together with the switching part. Due to a slight relative rotation of the switching part relative to the clamping ring, the corresponding clamp-standing clamping rollers are pushed out of their clamping gaps, so that these clamping rollers are no longer in clamping readiness. After unlocking these pinch rollers take the driver of the switching part the clamping ring with a positive fit. Now, in a known manner, the rotating drive part produce a translational displacement of the driven part. As soon as an external axial force, which is greater than the axial actuating force generated by the actuator on the driven part, acts on the drive part, an external torque resulting from this external force acts on the drive part, whereby a relative rotation of the drive part relative to the switching part is used. Due to this incipient relative rotation, the pinch rollers are inserted into their wedge-shaped forced clamping gap, so that the hollow cylindrical part is rotatably coupled to the clamping ring. Due to the external force introduced into the actuator according to the invention moments are therefore introduced via the switchable Klemmrollengesperre in the support member and can not cause any unwanted adjustment movement of the actuator.

A particularly compact actuator according to the invention provides a housing in which the designed as an electric motor motor, the switchable locking mechanism and the transmission are housed. Preferably, the housing may be the motor housing of the electric motor at the same time.

If the threaded spindle is formed on the driven part, it is expedient to protect the provided with the threaded spindle part of the driven part against contamination. In this case, it may be useful if a bellows is provided, which is on the one hand attached to the housing, and on the other hand outside of the housing is fixed to the drive part and includes the threaded spindle.

Actuators according to the invention can undertake safety-relevant functions in the chassis of motor vehicles. For example, an active suspension link of a motor vehicle for the active adjustment of the camber or the active roll compensation be provided with an actuator according to the invention, wherein the output part of the actuator articulates an actuating element of the suspension arm, and wherein the actuator is supported frame fixed.

Instead of the above-described switchable Klemmrollengesperre so-called switchable Klemmkörpergesperre can be used. In this case, the clamping ring and the hollow cylindrical part are each equipped on their mutually facing lateral surfaces with a cylindrical clamping track. The clamping bodies are then arranged in the annular gap formed by these cylindrical clamping webs and spring-loaded with their clamping body surfaces against the cylindrical clamping webs. By tilting the clamp body they can be brought out of clamping engagement with the cylindrical clamps. Consequently, the switching part is designed such that a tilting of the clamping body can be accomplished.

Due to the reliability are actuators according to the invention, in particular in the automotive field for active adjustment of the camber, for active adjustment of the wheel track, for example in the rear axle steering, also for active Fußpunktverstellung a suspension spring in an electromechanical level control.

If actuators according to the invention are provided with the ball screw described above, instead of the spindle nut, the threaded spindle can be driven by the motor, in which case the spindle nut is arranged rotationally fixed. The frame-fixed support of the spindle or the spindle nut may be provided for example on the chassis joint.

The invention will be explained in more detail with reference to an embodiment shown in three figures. Show it:

1 shows a cross section through a wheel of a motor vehicle with an actuator according to the invention for the active camber adjustment,

Figure 2 shows the actuator of Figure 1 in longitudinal section and

3 shows a perspective view of a detail of the actuator according to FIG. 2 and FIG

Figure 4 shows another actuator according to the invention in a perspective view in partial longitudinal section.

Figure 1 shows in cross section a vehicle wheel of a motor vehicle and Parts of the suspension. The wheel bearing 1 of the vehicle wheel has an outer ring 2 which is spherically shaped on its outer surface and is arranged in a pivot bearing 3, which allows pivoting movements of the vehicle wheel for adjusting the camber. The pivot bearing 3 has a virtual axis of rotation D. The camber can be adjusted by pivoting the wheel about this virtual axis of rotation D.

For active camber adjustment, an actuator 5 is provided which is fixedly mounted on its bearing eye 6 in a frame-fixed manner on a gearing part 6a which is only schematically indicated here. An output part 7 of the actuator 5 is pivotally connected to a lever arm 8 of the outer ring 2 of the wheel bearing 1. To adjust the camber, the output member 7 is displaced translationally, whereby the outer ring 2 is pivoted about a pivoting of the lever arm 8 in the pivot bearing 3. The lever arm 8 forms an adjusting element 8a whose adjustment causes, for example, a change in the camber.

FIG. 2 shows a longitudinal section through the actuator 5. The actuator 5 comprises a motor 9a designed as an electric motor 9, which has a housing 10, a stator 11 indicated diagrammatically and a rotor 12 which at the same time forms the motor shaft 12a.

The actuator 5 further comprises a ball screw 13 designed as a gear 13a, the spindle nut 14, a drive member 14a and forms a rolling bearing 15 (four-point ball bearing) is mounted in the housing 10. The ball screw 13 further includes a threaded spindle 16, which is formed in the present case in axial extension integral with the driven part 7. In a known manner 16 not shown here balls are arranged between the spindle nut 14 and the threaded spindle, which roll on raceways 17, 18 of the spindle nut 14 and the threaded spindle 16 and rotate in endless ball tracks. A rotation of the spindle nut 14 is converted into a translation of the threaded spindle 16. The rotor 12 of the electric motor 9 - that is the Motorweüe 12a - is coupled via a switchable Klemmrollengesperre 19 to the spindle nut 14 of the ball screw 13. The switchable Klemmrollengesperre 19 is a locking 19a.

The switchable Klemmrollengesperre 19 is shown in Figure 3 in perspective view and described in detail below.

The threaded spindle 16 is translationally displaced by rotation of the spindle nut 14 and can project beyond the housing 10 on the front side. The ingress of impurities in the ball screw 13 is prevented in that a bellows 20 is provided, which bears tightly with its one end to the one end face of the housing 10, and tightly abuts with its other end to the driven part 7. Thus, the threaded spindle 16 is completely sealed to the outside.

Figure 3 shows a perspective view of the switchable Klemmrollengesperre 19. It comprises a clamping ring 21 which is rotatably mounted on the not shown here spindle nut 14 of the ball screw 13. It also includes a hollow cylindrical part 22, of which only one segment is shown here in a schematic representation. The clamping ring 21 and the hollow cylindrical part 22 are arranged coaxially with each other. The hollow cylindrical part 22 is rotatably connected to the housing 10 electric motor 9 and forms a frame-fixed support member 22 a. The hollow cylindrical portion 22 is presently integrally connected to the housing 10 and thus forms a part of this housing 10. Between the hollow cylindrical portion 22 and the clamping ring 21, a plurality of pairs of pinch rollers 23 are arranged distributed in the circumferential direction. Between two pinch rollers 23 of a pair, a compression spring 24 is in each case arranged, which is spring-loaded against the two pinch rollers 23.

The clamping ring 21 is provided with a plurality of clamping ramps 25, 26, wherein a pair of clamping ramps 25, 26 are associated with each pair of clamping rollers 23. ren, which have an opposite ramp slope.

The hollow cylindrical part 22 is provided on its inner circumference with a cylindrical clamping track 27 which defines together with the clamping ramps 25, 26 of the clamping ring 21 wedge-shaped clamping gaps 28, in which the two pinch rollers 23 of each pair are spring-loaded by the compression springs 24, in Accordingly, the pinch rollers 23 are in constant clamping engagement with the cylindrical clamping track 27 and the clamping ramps 25, 26. The clamping gaps 28 of each pair taper in opposite directions, the clamping gap 28 in a clockwise direction , the other counterclockwise.

The switchable Klemmrollengesperre 19 further includes a switching part 29 for unlocking the pinch rollers 23. When the pinch rollers 23 are released, they are no longer in clamping readiness with the cylindrical clamping track 27 and the clamping ramps 25 or 26. The switching part 29 is provided with buttons 30 as a contact surface for the pinch rollers 23 provided. The switching part 29 is relatively rotatable relative to the clamping ring 21 within a switching angle. This shift angle is limited by a positive entrainment of the clamping ring 21 by the switching member 29. This positive entrainment is ensured by provided on the switching member 29 driver 31, which abut against stops 32 of the clamping ring 21 when the switching member 19 is pivoted relative to the clamping ring 21.

In the present case, the switching member 29 is provided with a plurality of circumferentially spaced claws 33 which engage in grooves 34 of the clamping ring 21 with play in the circumferential directions. The groove walls form the stops 32. The drivers 31 and the buttons 30 are formed on the claws 33.

The switching part 29 is rotatably connected to the motor shaft 12a of the electric motor 9. The operation of the actuator according to the invention will be explained in more detail below. To adjust the camber of the electric motor 9 is actuated. The rotor 12 and the switching part 29 start to rotate together. Within the switching angle range, first the rotor 12 rotates with the switching part 29 relative to the rotationally fixed to the spindle nut 14 of the ball screw 13 connected clamping ring 21. During this relative rotation of the switching member 29 relative to the clamping ring 21, for example in a clockwise direction (see Figure 3), the release of clamping rollers 23 and then the entrainment of the clamping ring 21st

In FIG. 3, of each pair of pinch rollers, the respectively left pinch roller 23 is contacted by the adjacent button 30 and pushed away from the respective clamping ramps 25. That is, these pinch rollers 23 are displaced in the nips 28 toward the extended end of the nip 28. These left side arranged pinch rollers 23 of all pairs of clamping rollers are then out of clamping engagement. When these clamping rollers 23 arranged on the left side of all pairs of clamping rollers are released, the drivers 31 of the switching part 29 strike against the abutment 32 of the clamping ring 21: the grooves 34 of the clamping ring 21 are bounded on both sides by the stops 32 of the switching part 29 strike in the process described against the right in the circumferential direction stops 32 of the clamping ring 21. Now, the switching part 29 takes the clamping ring 21 and thus the spindle nut 14 of the ball screw 13 with a form-fitting. A torque transmission from the rotor 12 via the ball screw 13 to the output part 7 is thus ensured. By linear displacement of the driven part 7, the lever arm 8 is now pivoted, so that the camber is changed.

During the described power transmission from the electric motor 9 to the driven part 7, the clamping rollers 23 of all pairs of clamping rollers lying on the right in FIG. 3 still remain in clamping readiness with the clamping elements. Ramps 26 and the cylindrical clamping track 27. However, these pinch rollers 23 are not clamped, since due to the common relative rotation of the clamping ring 21 and the switching member 29 relative to the hollow cylindrical part 22 these right-lying pinch rollers 23 rolled toward the extended end of the nip 28 become. These pinch rollers can not pinch.

When the rotor 12 of the electric motor 9 is actuated in the opposite direction of rotation, the release operation of the pinch rollers 23 and the ent would take the clamping ring 21 in the same manner described, in which case, however, the right lying pinch rollers 23 of all pairs of pinch rollers are released from the switching part 29 , And wherein the driver 31 abut the respective left stops of the grooves 34 to take the clamping ring 21 positively.

Is the electric motor 9 de-energized, or are introduced due to potholes in the roadway large impact forces in the longitudinal direction of the driven part 7 in the ball screw 13, is ensured in the actuator 5 according to the invention that this shock or external force does not reach the rotor 12 of the electric motor 9 Without the locking mechanism provided according to the invention, a linear displacement of the driven part 7 and thus of the threaded spindle 16 would be used under this external force, which could initiate a rotational movement of the spindle nut 14. This would mean that the spindle nut 14 would rotate together with the clamping ring 21.

The locking prevents unwanted positioning movements. Assuming that the rotatably connected to the spindle nut clamping ring 21 wants to rotate under the external force in a clockwise direction (Figure 3), then the left lying pinch rollers 23 all Klemmrollenpaare are forced into their clamping gaps 28, so in this locking position torques on the pinch rollers 23 in the hollow cylindrical part 22 are initiated. This hollow cylindrical part 22 is part of the housing 10. About the axis of rotation of the rotor 12 of the electric motor 9 acting around torques introduced from the housing 10 via the bearing eye 6 in the here only schematically indicated frame-fixed frame part 6a. In this actuator 5 according to the invention, the locking position of the locking mechanism is automatically set when the driving force of the actuator 5 on the output part 7 is smaller than the mentioned external force.

As soon as a torque introduced into the clamping ring 21 via the spindle nut 14 is greater than a torque introduced into the clamping ring 21 by the electric motor 9, the clamping mechanism 19 blocks any further axial displacement of the driven part 7. In the case of the actuator 5 according to the invention, this is also the case Electric motor 9 sichergestelllt that no undesirable translational movements of the driven part 7 can begin. In the situations described (blocking position of the Klemmgesperres) of the actuator 5 is frozen.

In the present case, the clamping ring 21 of the switchable Klemmrollengesperres 19 is designed as a separate component and rotatably connected to the spindle nut 14. However, it is easily possible to perform the spindle nut 14 and the clamping ring 21 in one piece. For example, such a ring can be sintered in the sintering process. The raceways for the balls can then be formed on the inner circumference of this sintered part, and the clamping ramps and stops can be provided on the outer circumference of this so sintered part.

In the described embodiment, the hollow cylindrical portion 22 of the switchable Klemmgesperres is also part of the housing 10 of the electric motor 9. However, it is easily possible to perform the hollow cylindrical part as a separate ring which is rotatably disposed in a housing bore of the housing 10.

In the present case, a plurality of pairs of clamping rollers are provided. Alternatively, it is of course possible to provide any other arrangements of pinch rollers and Klemmrampenanordungen. It only has to Ensure that at least two clamping gaps are formed, which taper in the circumferential direction in the opposite direction.

The ramp angles of the clamping ramps are selected in the case of actuators according to the invention in such a way that a self-reinforcing effect occurs, wherein the loosening with a low torque expenditure of the motor is likewise possible. An automatic start or displacement of the threaded spindle is prevented.

Instead of the switchable Klemmrollengesperres described here also a switchable Klemmkörpergesperre can be provided. In a switchable Klemmkörpergesperre the clamping tracks for the clamping body are formed by two cylindrical clamping tracks, wherein the inner clamping track is formed on an inner member and the outer clamping track on an outer member. The clamping body are inserted in the annular gap formed by this clamping surfaces and distributed over the circumference. The clamping bodies each have on opposite sides a curved clamping body surface. These clamping bodies can be tilted about a tilting axis, wherein this tilting axis is formed here parallel to the axis of rotation of the rotor of the electric motor. These tilting axes are located approximately in the center of these clamping bodies. The clamping bodies are tilted, for example, by means of compression springs so that they want to raise themselves in the annular gap and be sprung against the cylindrical clamping surfaces of the inner and the outer part. In the case of such switchable sprag-type locking devices, a switching part is provided which can engage on each clamping body on both sides of the tilting axis. The clamping bodies are arranged so that in the one direction of rotation between the outer and the inner part of a clamping body are clamped, and that in the other direction of rotation between the inner and the outer part, the other clamping body are clamped. To unlock this switchable Klemmkörpergesperres the switching part switches the corresponding clamp body free, the respective clamp body tilted about its tilting axis and out of clamping engagement with the cylindrical Clamps are brought. The switching part is then provided, as in the exemplary embodiment described above, with drivers which abut against stops of the inner or the outer part and take it with a positive fit. As in the embodiment, such a switching member is rotatably connected to the rotor of the electric motor.

Actuators according to the invention can be equipped with sensors which detect the current position of the threaded spindle.

The switchable clamping roller lock and the switchable sprag lock, as well as switchable ratchet mechanism are switchable locking mechanisms that can be used for the invention.

The illustrated in Figure 4 actuator 35 according to the invention differs from the embodiment described above essentially in that a rod-shaped output member 36 penetrates a housing 37 with both ends, the two ends of the output member 36 outside of the housing 37 ange¬ to not shown here adjusting elements ange-. are shot. Another difference is that a waveguide 38 is additionally installed in the housing 37. The shaft guide 38 guides the longitudinally displaceable output member 36 and secures it against rotation about its longitudinal axis. The shaft guide 38 may be designed as a ball bushing. In this case, balls roll endlessly in an endless ball channel of the ball bushing. On opposite sides of the ball bushing and the Abreibsteiles 36 ball grooves are formed for the balls. The guidance of the balls in the ball grooves prevents rotational movements of the driven part 36 about its longitudinal axis. As in the case of the above-described actuator, the motor 37 houses the motor 9a, the rotor 12 and the ball screw 13 and the locking mechanism 19a. The mode of operation of the actuator 35 corresponds to that of the actuator 5: as soon as an external force in the longitudinal direction of the driven part 36, which is greater than the driving force of the actuator, engages the output part 36. At the output part 36, the locking mechanism 19a blocks any further displacement of the driven part 36 with respect to the housing 37, whereby the motor 9a is not loaded by the external force. The housing 37 is attached to a frame part not shown here. As with the above-described actuator 35 bellows are provided in the actuator, which are not shown here. These bellows are attached to both passages of the driven part 36 on the one hand to the housing 37 and on the other hand to the output part 36 directly adjacent. The actuators according to the invention described in the embodiments are of course not limited to the application for adjusting the camber; Rather, the described actuators according to the invention are also suitable for adjusting the wheel track and Fußpunktverstellung a suspension spring in an electromechanical level control.

LIST OF REFERENCE NUMBERS

1 wheel bearing 24 compression spring

2 outer ring 25 clamping ramp

3 Swing bearing 26 Clamping ramp

4 wheel carriers 27 cylindrical clamping track

5 actuator 28 nip

6 bearing eye 29 switching part

6a Frame part 30 Button

7 Stripping section 31 Take away

8 lever arm 32 stop

8a Control element 33 Claw

9 electric motor 34 groove

9a motor 35 actuator

10 housing 36 output part

11 stator 37 housing

12 rotor 38 shaft guide

12a motor shaft

13 ball screw -

13a transmission

14 spindle nut

14a drive part

15 rolling bearings

16 threaded spindle

17 career

18 career

19 pinch roller lock

19aGesperre

20 bellows

21 clamping ring

22 hollow cylindrical part

22a Supporting party I

23 clamping roller

Claims

claims

1. Actuator (5, 35), with a motor (9a), and with a driven part (7, 36) for connection to an actuating element (8a), characterized in that a locking mechanism (19a) is provided, the output part ( 7, 36) blocked when the driving force of the actuator (5) on the output member (7) is smaller than an outer, on the output member (7) engaging external force.

2. Actuator (5, 35) according to claim 1, wherein a motor shaft (12a) of the motor (9a) to a rotatable drive part (14a) of a transmission (13a) is connected, wherein the transmission (13a) is a rotation of the drive member (14a ) in a translation or rotation of the driven part (7, 36) of the transmission (13 a) converts.

3. Actuator (5, 35) according to claim 2, wherein the locking mechanism (19 a) between the drive part (14 a) of the transmission (13 a) and a support member (22 a) is arranged effectively, wherein the locking mechanism (19 a) in its blocking position the rotatable drive member (14a) rotatably connected to the support member (22a), and wherein the locking mechanism (19a) in its release position a

Relative rotation between the rotatable drive member (14a) and the support member (22a) releases.

4. Actuator (5, 35) according to claim 2, wherein in the locking position of the locking mechanism (19 a) on the rotatable drive member (14 a) attacking

Drive torque of the actuator (5, 35) is smaller than an external torque acting on the rotatable drive part (14a), which is generated on the basis of the external force acting on the driven part (7).

5. Actuator (5, 35), with a motor (9a), and with a ball screw (13), the output part (7, 36), threaded spindle (16) to an actuating element (8a) can be connected, and its drive part ( 14a) formed spindle nut (14) by the motor (9a) is driven thereby characterized in that a switchable locking mechanism (19a) between the spindle nut (14) and a support member (22a) is effectively arranged, the locking mechanism (19a) blocking the spindle nut (14) in its locking position and in its release position a relative rotation between the spindle nut (FIG. 14) and the support part (22a) releases.

6. Actuator (5, 35) according to one or more of the preceding claims, wherein in the blocking position of the Klemmgesperres one of the motor (9a) on the drive part (14a) transferable drive torque is smaller than a on the drive part (14a) transmittable external moment , which is generated due to an external force acting on the driven part (7, 36), wherein in the release position the drive torque is greater than the external torque.

7. Actuator (5, 35) according to one or more of the preceding claims, wherein a switchable Klemmrollengesperre (19) provided with clamping ramps (25, 26) clamping ring (21) and a hollow cylindrical part (22) with a cylindrical clamping track (27), which together with the clamping ramps (25, 26) wedge-shaped clamping gaps (28), in which clamping rollers (23) are arranged, which with the

Clamping columns (28) are switchable into and out of clamping engagement.

8. Actuator (5, 35) according to claim 7, wherein a non-rotatably connected to a motor shaft (12 a) of the motor (9 a) switching part (29) with Schaltflä- chen (30) for unlocking the pinch rollers (23) and with a driver (31) for positive entrainment of the clamping ring (21) is provided.

9. actuator (5, 35) according to claim 7, wherein the clamping ring (21) rotatably connected to the drive part (14 a) and coaxially in the hollow cylindrical part (22) is arranged, wherein the hollow cylindrical member (22) rotatably with the frame part (6a) is connected. 10. Actuator (5. 35) according to one or more of the preceding claims, wherein in a housing (10, 37) of the electric motor (9) formed as motor (9a), the switchable locking mechanism (19a), the motor (9a ) downstream gear (13 a), for example, the ball screw drive (13) are housed.

H .Aktuator (5, 35) according to claim 10, wherein the driven part (7) comprises the threaded spindle (16), wherein the driven part (7, 36) protrudes from the housing (10, 37), and wherein a bellows (20 ) on the one hand to the housing (10) and on the other hand outside of the housing

(10, 37) is attached to the output member (7, 36) and includes the threaded spindle (16).

12. Active suspension link of a motor vehicle, for example, for the active adjustment of the camber or for active roll compensation, with an actuator (5, 35) according to one or more of the preceding claims, wherein the output member (7, 36) of the actuator (5, 35 ) which articulates formed as a steering part adjusting element (8 a) of the suspension arm.