WO2008052884A1

WO2008052884A1 - Actuating device

Info

Publication number: WO2008052884A1
Application number: PCT/EP2007/061089
Authority: WO
Inventors: Andreas Nendel; Harald Elendt
Original assignee: Schaeffler Kg
Priority date: 2006-11-03
Filing date: 2007-10-17
Publication date: 2008-05-08
Also published as: DE102006051809A1

Abstract

Proposed is an actuating device (1) having at least one actuator pin (3) which can be deployed from a rest position into a working position, in particular for adjusting a cam piece, which is arranged in a rotationally fixed and longitudinally movable manner on a support shaft, of a variable-lift valve drive of an internal combustion engine. The actuating device has an activatable holding device (18) for holding the actuator pin in the rest position and for releasing the actuator pin from the rest position. Here, the holding device should be designed to act in a form-fitting manner by virtue of a blocking pin (26) interacting with blocking bodies (22) in such a way that the blocking pin supports the blocking bodies in the radially outward direction against a radial recess (9) in order to hold the actuator pin in the rest position, and that the blocking pin releases the blocking bodies in the radially inward direction in order to release the actuator pin from the rest position.

Description

Name of the invention

locking device

description

Field of the invention

The invention relates to an adjusting device with at least one mounted in a longitudinal guide of a housing and relative to the housing from a retracted rest position in a working position extendable actuator pin for adjusting a cooperating with the adjusting machine part. This is in particular designed as a support shaft rotatably and longitudinally displaceable cam piece of a variable-stroke valve drive of an internal combustion engine and has a spiral displacement groove into which a first end portion of the actuator pin can be coupled in the working position. In this case, the adjusting device has a controllable holding device for holding the force-loaded by a spring means in the direction of the working position Aktuatorstifts in the rest position and for releasing the Aktuatorstifts from the rest position.

Background of the invention

Such a control device is apparent from the considered as generic type WO 03/021 612 A1. Its holding device for the actuator pin is based on the interaction of an electromagnet with a permanent magnet fixed to the actuator pin, the magnetic attraction of which holds the actuator pin against the force of the spring means in the rest position on the non-energized electromagnet. To release the actuator pin from the rest position Position is merely a pulse-like current application of the electromagnet to overcome the magnetic attraction of the permanent magnet required, the actuator pin is accelerated not only by the force of the spring means but also by the force of a magnetic repulsion effect between the permanent magnet and the energized electromagnet in the direction of the working position.

Such, with low power consumption quickly and temporally exactly switching actuator is particularly suitable for adjusting a variable stroke valve train, as is apparent, for example from DE 10 2004 021 376 A1. The stroke variability of the valve drive proposed there is based on a cam piece with cams arranged adjacently thereon, the different opening characteristics of which are selectively transmitted to a gas exchange valve by means of a conventionally rigid cam follower. For operating point-dependent adjustment of these opening courses, the cam piece is non-rotatably but longitudinally displaceable on a carrier shaft and has two helical and oppositely extending sliding grooves, in which the end portions of the actuator pins of two adjusting devices of the type mentioned are alternately coupled. While the axial course of the sliding groove engaged with the respective actuator pin causes the cam piece to move from cam to cam in a self-controlling manner and camshaft angle, the radial course of each cam groove is designed so that it slides towards the end of the cam groove Shifting operation is increasingly flatter and the currently engaged actuator pin actively shifted from its working position back to the rest position.

Although this active return function of the sliding grooves is an essential prerequisite for the low power consumption of the proposed in the erstzitten document actuator, the operating principle of the holding device can still be associated with various disadvantages. On the one hand, these include the size of the sufficient to produce a sufficient Holding force required effective area between the electromagnet and the permanent magnet whose radial space requirement is considerably greater than that of the Aktuatorstifts. Due to this space requirement, there is always the increased risk, in the case of the illustrated variable-stroke valve drive, that the adjusting device to be integrated into an already existing cylinder head architecture collides incompatible with the existing surrounding construction. Thus, the usability of this adjusting device, in particular in a variable-stroke valve drive of the same type, as proposed in DE 196 1 1 641 C1, would prove extraordinarily difficult to constructively. Because the cam piece proposed there has three cams with different opening pattern and is displaced by a pair of adjacently arranged adjusting devices in the two displacement directions. Since each pair of actuators has a distance of the actuator pins corresponding to a cam width and this is to be kept comparatively small, taking into account the freedom of movement of the cam piece to adjacent camshaft bearing points, it would come in this case to an inadmissible penetration of the actuators in the magnet.

Another disadvantage of this adjusting device, on the other hand, is its high manufacturing and thus cost, resulting from the known complex production technical handling of the permanent magnet with its magnetic properties.

Object of the invention

The present invention is therefore the object of an adjusting device of the type mentioned in such a way that the disadvantages are avoided. Accordingly, the holding device should have a minimum of additional radial space required compared with the actuator pin, so that the adjusting device can be integrated into existing machine architecture without or at least with reasonable design effort. Ren and in particular in cylinder heads of internal combustion engines can be integrated. In addition, the actuator should be as simple as possible and inexpensive to produce under high volume conditions.

Summary of the invention

The solution to this problem arises from the features of claim 1, while advantageous developments and refinements the dependent claims are removed. Accordingly, the object is achieved in that the holding device is formed positively acting and has at least the following features:

- A running in a second end portion of the actuator pin longitudinal bore and a longitudinal bore intersecting transverse bore;

- A running in the longitudinal guide of the housing and in the rest position of the Aktuatorstifts with the transverse bore aligned radial recess;

- One or more displaceably arranged in the transverse bore locking body and

- A controllable actuator with a displaceably arranged in the longitudinal bore locking pin which moves in the transverse bore and cooperating with the locking bodies such that the locking pin, the locking body, for holding the Aktuatorstifts in the rest position, supported in radially outward direction against the radial recess and that of Locking pin releases the locking body, for releasing the actuator pin from the rest position, in a radially inward direction.

Accordingly, the adjusting device according to the invention has a holding device which does not fix the actuator pin via magnetic attraction forces with correspondingly large effective area according to the cited prior art, but by positive engagement against the force of the spring means in its rest position. The remaining space required for the holding device is now significantly reduced, since the required holding force here as a form-fitting clamping force generated over a magnetic effective area considerably smaller Contact area required. Specifically, this contact surface is formed by the radial recess, in which the blocking member or members projecting from the transverse bore thereof in the rest position of the actuator pin and supported by the blocking pin are supported to generate the greatest possible clamping forces. In contrast, the applied to release the actuator pin from this locked rest position of the actuator actuation forces only need to overcome the frictional forces occurring between the locking pin and the locking bodies. Since these frictional forces are many times lower than the producible clamping forces, the actuating device can also be designed to be very small, regardless of its physical operating principle, as far as possible.

In a further development of the invention, the transverse bore should be formed as a through hole and two locking bodies arranged on both sides of the locking pin should be provided. On the one hand, this arrangement is advantageous over only one blocking body, since larger clamping forces can be generated either with identical dimensioning of the blocking body or with smaller dimensioning of the blocking body - corresponding to a further reduced space requirement of the holding device - the possibly already sufficient clamping force of only one clamping body can be generated. On the other hand, this arrangement has the advantage of fewer components and the restriction to only one transverse bore in Aktuatorstift compared to three or more sprags.

In a further embodiment of the invention, the blocking body should be formed as balls. These can be removed as extremely low-cost mass product of a Wälzkörperfertigung, it may be appropriate that a cooperating with the balls end portion of the locking pin tapers in the direction of its ball-side end conically. This embodiment allows a particularly low-wear sliding or rolling contact between the balls and the locking pin, just before the actuator pin returns to its rest position. Because in this phase of movement they must first completely in the transverse bore aufhaltenden balls are displaced by the then running in the transverse bore locking pin as free of edge pressures radially outward in the direction of the radial recess. Compared to a locking pin with a purely cylindrical end portion not only abruptly occurring edge contact on the locking pin is prevented by the contact between the conical surface of the conical end portion and the ball surface, but also favors a smooth sliding or rolling of the balls on the conical surface in radially outward direction.

In addition, it is provided that the radial recess is formed as an annular groove with a radially inwardly conically tapering and serving in the rest position of Aktua- torstift as a support surface for the balls axial shoulder. The annular groove represents an advantageous alternative to locally formed radial recesses which, in accordance with the number of balls used, can be designed, for example, as bores aligned with the transverse bore in the longitudinal guide of the housing. A disadvantage of such a configuration, however, is the then required additional effort to secure the Aktua- torstift against rotation in the longitudinal guide to ensure the radial alignment of the holes with the transverse bore in the rest position of the actuator.

With regard to an annular groove which is particularly easy to manufacture, a bushing arranged in a stationary manner in the housing is provided as part of the longitudinal guide, which bushing axially delimits the annular groove with its annular end face facing the axial shoulder. In this case, it makes sense to provide the housing with a diameter-stepped bore, so that, based on the first end portion of the Aktuatorstifts, this side of the transverse bore extending part of the longitudinal guide directly in the housing and beyond the transverse bore extending part of the longitudinal guide formed by the nenmantelfläche the socket. In order to also ensure a free from edge carriers and wear ßarm contact the balls with the annular end face to which the balls can strike in the movement phase of the Aktuatorstifts shortly before re-reaching the rest position, should also be formed the annular face substantially mirror symmetry to the axial shoulder.

In a particularly preferred embodiment of the invention, the actuating device should be designed as a Elektrohubmagnet with a locking pin actuated anchor. Although the actuator can also be based on other known, for example, hydraulic or pneumatic action principles, the electromagnetically controlled locking pin can be actuated particularly quickly and with high precision. With regard to low production costs, the locking pin and the armature can also be combined to form a one-piece component. In this case, the different mechanical and electromagnetic requirements for the component properties, for example, by adapted material selection with an optionally required, wear-resistant surface coating can be taken into account.

Furthermore, the adjusting device should be designed as a structural unit comprising at least the housing, a housing arranged in the group of actuator pins, the actuator pins kraftbeaufschlagenden spring means and the mutually independently controllable holding devices. Such a structural unit is particularly suitable in the case of the variable-stroke valve drive as a separately manufactured from the cylinder head of the engine and ready-to-install supplier part, which can also be inexpensively constructed modular depending on the number of actuator pins. Alternatively, it can nevertheless be provided to arrange the actuator pins in a housing common to the machine part and the adjusting device, so that the actuator pins are mounted as housings in the cylinder head of the internal combustion engine directly or by means of bushes in the case of the variable-displacement valve drive. Moreover, the actuator pin and designed as a helical compression spring spring means are to be rotatably decoupled by means of a sliding disk arranged between them. As a result, a transmission of a rotary movement of the actuator pin, which can be caused by the frictional contact of the actuator pin on the sliding groove, is prevented on the helical compression spring, so that it is not twisted impermissibly with regard to its fatigue strength.

According to a further preferred embodiment of the invention, the locking pin should be subjected to force in the direction of the transverse bore by the force of a spring formed as a helical compression spring further Feeder, wherein the further spring means is supported on a fixedly connected to the locking pin Axialbund. Although a Federkraftbeaufschlagung the locking pin for the function of the adjusting device is not absolutely necessary, since this would be kraftbeaufschlagbar in a particularly low-friction trained adjusting device only by gravity action in the direction of the transverse bore, supports the other spring means the predetermined for the function of the actuator movement sequence of locking pin. This sequence of movements is explained in more detail in the context of the description of an embodiment.

Furthermore, it is provided that the spring means and the further spring means are concentric and abut with their the sliding disk or the Axialbund facing away from the spring ends to a stationary in the housing support disk. Advantageously, the support disk also has a surface on which the ends of the two helical compression springs can rotate simultaneously. This is useful if the rotation of the actuator pin is transmitted by friction in the longitudinal bore on the locking pin and consequently its the axial compression coil supporting the helical compression spring. Also in this case would be without further measures the risk that the rotation of the Axialbunds is transmitted to the helical compression spring of the locking pin and leads to excessive friction force on the opposite spring support to an unacceptable twist this helical compression spring. To avoid a resulting damage to the helical compression spring, it can Nevertheless, it may also be expedient to additionally or alternatively provide the spring support of the axial collar with favorable sliding properties.

Finally, the support plate can also serve for defined stroke limitation of the locking pin by the locking pin has a fixedly connected to this further Axialbund, which abuts in the direction of the transverse bore on the side facing away from the spring ends of the support disk.

Brief description of the drawings

Further features of the invention will become apparent from the following description and from the drawings, in which an embodiment of an adjusting device according to the invention is shown in simplified form. Unless otherwise stated, the same or functionally identical features or components are provided with the same reference numerals. Show it:

Figure 1 is designed as a structural unit actuating device with three Aktua- torstifte in perspective longitudinal section and

2 shows the adjusting device according to Figure 1 in uncut perspective view.

Detailed description of the drawings

In Figure 1, an actuating device 1 according to the invention is disclosed, which is used to control a known variable stroke drive of an internal combustion engine, not shown here. The basic operating principle of such a valvetrain is derived, for example, from the publications DE 196 11 641 C1 and DE 10 2004 021 376 A1 cited at the beginning, and can be summarized to the effect that instead of a conventional one rigidly formed camshaft, a carrier shaft is provided with a rotatably and longitudinally displaceable cam piece arranged thereon. The cam piece has one or more groups of axially adjacent cams with a different opening profile, which serve for operating point-dependent actuation of gas exchange valves. The required for the selective activation of the respective cam displacement of the cam piece on the support shaft via spiral displacement grooves on the cam piece, which differ according to the direction of displacement in their orientation and brought depending on the instantaneous position of the cam piece with first end portions 2 selectively actuated actuator pins 3 into engagement become.

In the adjusting device 1 disclosed here is a separately manufactured and assembled in the cylinder head of the engine assembly with a common housing 4 and a group of three arranged therein and cylindrically shaped actuator pins 3. These are mounted in longitudinal guides 5 of the housing 4, wherein each of the longitudinal guides 5 is formed, on the one hand, by the diameter-reduced section of a stepped bore 6 in the housing 4 and, on the other hand, by the inner lateral surface 7 of a bush 8 drawn into the diameter-enlarged section of the stepped bore 6. In this way can be produced with simple manufacturing means radial recesses 9 in the form of an annular groove 10 which is limited in the axial direction by a housing-side axial shoulder 1 1 on the one hand and by a sleeve-side annular end face 12 on the other.

For a better understanding, the actuator pins 3 are shown in different axial positions. In this case, the left in Figure 1 actuator pin 3 is in its retracted rest position, ie, the first end portion 2 is out of engagement with the sliding groove. The right actuator pin 3, however, is in its extended working position, ie, the first end portion 2 is in engagement with the sliding groove. The middle actuator pin 3 is in the state of movement shortly after leaving its rest position. Due to the modular construction of the actuator 1 with three identical kits, each containing one of the actuator pins 3 and the components involved in its operation, only one of the kits is explained below for linguistic simplification. For applying the actuator pin 3 from the rest position to the working position driving force is a spring means 13 which clamped in the form of a helical compression spring 14 between a stationary housing 4 resting on the support disk 15 on the one hand and a front side of a second end portion 16 of the actuator pin 3 adjacent sliding disk 17 on the other are. The object of the sliding disk 17 is to decouple the actuator pin 3 rotationally from the helical compression spring 14 so that a rotation of the first end portion 2 of the actuator pin 3 located in the engaged state with the sliding groove does not lead to a twisting of the helical compression spring 14.

To control the actuator pin 3, the adjusting device 1 has a controllable holding device 18, which holds the actuator pin 3 in the rest position and, if necessary, releases from the rest position (the three holding devices 18 are, of course, independently controllable). According to the invention, the holding device 18 is of positive-locking design and comprises the following features or components: a longitudinal bore 19 extending in the second end section 16 of the actuator pin 3;

- A longitudinal bore 19 intersecting and formed as a through hole transverse bore 20; - In the rest position of the actuator pin 3 with the transverse bore 20 aligned annular groove 10;

- Two slidably disposed in the transverse bore 20 and designed as balls 21 locking body 22 and

- A controllable actuator 23, the net here as Elektrohubmag- 24 with an armature 25 and actuated by this and in the

Longitudinal bore 19 slidably disposed locking pin 26 is formed. Starting from the rest position of the - left in Figure 1 - Actuator 3, the sequence of movements of the adjusting device 1 is described below. The actuator pin 3 is thereby held in the rest position so that an end portion 27 of the locking pin 26 cooperating with the balls 21 is sufficiently far in the transverse bore 20 to support the balls 21 in radially outward direction against the axial shoulder 11 of the annular groove 10 , To release the - in Figure 1 average - actuator pin 3 from the rest position of the anchor

25 energized coil 28 of the Elektrohubmagneten 24 so that the here formed integrally with the armature 25 locking pin 26 is raised in the Querboh- tion 20 and the balls 21 releases in radially inward direction. The lifting of the locking pin 26 takes place counter to the force of a further spring means 29 which is formed as disposed within the helical compression spring 14 concentric to this helical compression spring 30 and clamped between the support plate 15 and a fixedly connected to the locking pin 26 Axialbund 31.

In order to ensure the highest possible acceleration of the actuator pin 3 from the rest position, and at the same time to reduce the contact pressures between the balls 21 and the axial shoulder 1 1, the Axialschul- ter 1 1 tapers conically in the radially inward direction. Consequently, the lock pin

26 released and completely in the transverse bore 20 displacing balls 21 roll on the axial shoulder 1 1 or slide off. Subsequently, the right-hand actuator pin 3 in FIG. 1 is driven into its working position by the force of the helical compression spring 14, in which its first end section 2 is coupled in the helical sliding groove on the cam piece in order to displace it by a cam width. As can be seen from the illustration of this actuator pin 3 further, the Elektrohubmagnet 24 is already energized in the working position again and no longer attracts the armature 25. For limiting the stroke of the locking pin 26, a further axial collar 32, which is firmly connected to the latter and serves as a simple diameter widening in the transition region to the armature 25, is used in this exemplary embodiment the spring ends 33 of the helical compression springs 14 and 30 facing away from the support plate 15 abuts.

The required after the displacement of the cam piece return of the actuator pin 3 in its rest position is known to be done by the sliding groove itself in which the spiral shape expires radially uplifting and drives the actuator pin 3 back to the rest position. Shortly before reaching the rest position, the balls strike 21 on the end portion 27 of the locking pin 26 and raise it in the direction of the Elektrohubmagneten 24 at. This state in turn corresponds to the representation of the middle in FIG. 1 actuator pin 3, but the Elektrohubmagnet 24 is still in the energized state. Finally, the now released in radially outward direction balls 21 slide on the tapered in the direction of its ball-side end face 34 end portion 27 of the locking pin 26 back into the annular groove 10. At the same time the locking pin 26 by the force of the helical compression spring 30 back in Towards the direction of the transverse bore 20 and locks the balls 21 in the radially inward direction.

Thus, the actuator pin 3 safely reaches the locked rest position, taking into account component tolerances, and at the same time to prevent a sliding, wear ßfördernden contact between the end face 35 of the first end portion 2 and the cam piece outside the sliding groove, it is further provided, the sliding groove in her Outlet area to be provided with at least one acting in the radial direction acceleration ramp. Upon rotation of the cam piece, this acceleration ramp causes the actuator pin 3 to lift due to its inertia against the bottom of the sliding groove and to safely return to the locked rest position after a free-flying phase of the order of 1 mm or less. In order to ensure the safe return of the actuator pin 3 even at low rotational speeds of the cam piece, it is also possible to provide two or more successive acceleration ramps whose specific or rotational speed-independent acceleration values are in the direction of rotation of the cam pin. Increase in number. Such an embodiment is based on the consideration that for lifting off the actuator pin 3 at high rotational speeds of the cam piece, a lower specific acceleration value is required than at low rotational speeds. Accordingly, at high speeds, the actuator pin 3 would already be reliably driven back to the rest position with the first acceleration ramp and at low rotational speeds of the cam piece only with the second or last acceleration ramp, without exceeding acceleration or noise-critical acceleration limit values. In this context, it should also be mentioned that the annular end face 12 of the bushing 8 is formed with an inner bevel 36 substantially mirror-symmetrical to the axial shoulder 1 1 of the annular groove 10 to the occurring at a dynamically induced abutment of the balls 21 on the annular end face 12 contact pressures on a low To keep level.

An uncut general view of the adjusting device 1 is finally shown in FIG. For simplicity, the representation required for the control of the Elektrohubmagneten 24 power cables or connectors has been omitted. However, the flange-like housing 4 with screwing points 37 for fastening the adjusting device 1 on the cylinder head and a closure cover 38 bolted to the housing 4 are clearly recognizable.

List of reference numbers

1 adjusting device

2 first end portion of the Aktuatorstifts

3 actuator pin

4 housing

5 longitudinal guide

6 step drilling

7 Inner circumferential surface

8 socket

9 radial recess

10 ring groove

1 1 axial shoulder

12 ring end face

13 spring means

14 helical compression spring

15 support disk

16 second end portion of the Aktuatorstifts

17 sliding disk

18 holding device

19 longitudinal bore

20 cross bore

21 ball

22 locking body

23 actuator

24 electric lifting magnet

25 anchors

26 locking pin

27 end portion of the locking pin

28 Coil of Elektrohubmagneten

29 more spring means

30 helical compression spring Axial collar Additional axial collar Spring end Ball-side end face of the locking pin End face of the first end section Inner bevel of the annular end face Screw connection point Cover

Claims

claims

Adjusting device (1) with at least one actuator pin (3) mounted in a longitudinal guide (5) of a housing (4) and movable relative to the housing (4) from a retracted rest position to a working position for adjusting a machine part interacting with the adjusting device (1), in particular designed as a support shaft rotatably and longitudinally displaceable cam piece of a variable-stroke valve drive an internal combustion engine is formed and a spiral

Sliding groove, in which a first end portion (2) of Aktua- torstift (3) in the working position can be coupled, wherein the adjusting device (1) a controllable holding device (18) for holding the force of a spring means (13) in the direction of the working position Actuator pin (3) in the rest position and for releasing the actuator pin (3) from the rest position, characterized in that the holding device (18) is formed positively acting and has at least the following features:

- A longitudinal bore (19) extending in a second end section (16) of the actuator pin (3) and a transverse bore (20) intersecting the longitudinal bore (19);

- A in the longitudinal guide (5) of the housing (4) extending and in the rest position of the actuator pin (3) with the transverse bore (20) aligned radial recess (9); - One or more in the transverse bore (20) slidably disposed

Locking body (22) and

- A controllable actuator (23) with a in the longitudinal bore (19) slidably disposed locking pin (26) which moves in the transverse bore (20) and with the locking bodies (22) cooperates such that the locking pin (26) the locking body (22), for holding the actuator pin (3) in the rest position, in the radially outward direction against the radial recess (9) is supported and that the locking pin (26) the locking body (22), for releasing the actuator pin (3) from the rest position, releases in radially inward direction.

2. Adjusting device according to claim 1, characterized in that the transverse bore (20) is formed as a through hole and that two on both sides of the locking pin (26) arranged locking body (22) are provided.

3. Adjusting device according to claim 1, characterized in that the blocking bodies (22) are formed as balls (21).

4. Adjusting device according to claim 3, characterized in that a cooperating with the balls (21) end portion (27) of the locking pin (26) in the direction of its ball-side end face (34) tapers conically.

5. Adjusting device according to claim 3, characterized in that the radial recess (9) as an annular groove (10) with a radially inwardly tapered and serving in the rest position of the Aktuatorstifts (3) as Ab support surface for the balls (21) axial shoulder ( 1 1) is formed.

6. Adjusting device according to claim 5, characterized in that a stationary in the housing (4) arranged bushing (8) is provided as part of the Längsfüh- tion (5), which bushing (8) the annular groove (10) with their the

Axially shoulder (1 1) facing annular end face (12) axially limited.

7. Adjusting device according to claim 6, characterized in that the annular end face (12) is formed substantially mirror-symmetrically to the axial shoulder (1 1).

8. Adjusting device according to claim 1, characterized in that the actuating device (23) as Elektrohubmagnet (24) with a locking pin (26) actuating armature (25) is formed.

9. Adjusting device according to claim 8, characterized in that the locking pin (26) and the armature (25) are integrally formed.

10. Adjusting device according to claim 1, characterized in that the adjusting device (1) is designed as a structural unit, the at least the housing (4), in the housing (4) arranged group of actuator pins

(3), the actuator pins (3) kraftbeaufschlagenden spring means (13) and the independently controllable holding devices (18) summarizes.

1 1. Adjusting device according to claim 1, characterized in that the actuator pin (3) and designed as a helical compression spring (14) spring means (13) are rotatably decoupled by means of a sliding disc (17) arranged between these.

12. Adjusting device according to claim 1, characterized in that the locking pin (26) by the force of a helical compression spring (30) formed further spring means (29) in the direction of the transverse bore (20) is subjected to force, wherein the further spring means (29) a fixedly connected to the locking pin (26) axial collar (31) is supported.

13. Adjusting device according to claims 1 1 and 12, characterized in that the spring means (13) and the further spring means (29) extend concentrically and with their sliding disc (17) or the axial collar (31) facing away from the spring ends (33) a stationary in the housing (4) arranged supporting disc (15) abut.

14. Adjusting device according to claim 13, characterized in that the

Locking pin (26) has a fixedly connected to this further Axialbund (32) for limiting the stroke of the locking pin (26) in the direction of

Transverse bore (20) on the spring ends (33) facing away from the support disc (15) abuts.