Actuating device for an automated manual transmission

An actuating device (10) for an automated manual transmission (12) includes a pressure-medium-operated actuator (54) having a piston (58) and a piston rod (64) connectable to the selector element or shift element of the manual transmission. The piston is arranged in a cylindrical receiving chamber (50) of the housing (18) of the actuator and is coaxially movable therein. A sensor system (30)includes a magnet (38) arranged on a holding device (44) and a magnetic-field-sensitive sensor (32) is arranged on the housing radially with respect to the magnet (44).The holding device has a hollow cylindrical geometry, an anti-rotation element (80)is form-lockingly accommodated in an associated recess in the housing (18), and that the anti-rotation element extends across the holding device in the manner of a secant such that rotational movement of the holding device is blocked, although axial and rotational movement of the piston are possible.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a 35 U.S.C. § 371 national phase application of International Application No.: PCT/EP2021/068562, filed Jul. 6, 2021, which claims the benefit of priority under 35 U.S.C. § 119 to German Patent Application No.: 10 2020 118 052.7, filed Jul. 8, 2020, the contents of which are incorporated herein by reference in their entirety.

FIELD

The present disclosure relates to an actuating device for an automated manual transmission of a motor vehicle, by which actuating device a selector element or shift element of the manual transmission is movable for setting a shift gate or for engaging or disengaging a gear, wherein the actuating device includes a pressure-medium-operated actuator having a piston and a piston rod, which is connectable to the selector element or shift element of the manual transmission, wherein the piston is arranged in a radially sealed manner in a cylindrical receiving chamber of the housing of the actuating device and is coaxially movable in the receiving chamber, wherein a sensor system that includes a magnet and a magnetic-field-sensitive sensor is provided, and wherein the magnet is arranged on the end face of the piston remote from the piston rod by a holding device and the sensor is arranged radially with respect to the magnet on the housing.

BACKGROUND

DE 10 2005 034 865 A1 describes an adjusting device for a motor vehicle transmission. This adjusting device includes at least one movable adjusting element, the position of which is detected by at least one sensor, wherein a code path is provided, which includes sections having different heights, the sections being designed to be scanned by the sensor. According to the invention, the sections of the code path having different heights are arranged at least two-dimensionally. Preferably, the sections of the code path having different heights are contactlessly scanned by a sensor. A complete mechanical decoupling of this type is advantageous under certain surroundings conditions, such as, for example, in the presence of great temperature fluctuations or strong vibrations. According to this related art, the at least one sensor can be a Hall sensor, which contactlessly interacts with a magnet.

SUMMARY

It is an object of the present disclosure to provide an actuating device, which includes an actuator in the form of a piston-cylinder arrangement, which has a magnet at its moving adjusting element, the magnet acting as part of a sensor system for determining the position of the adjusting element and for determining the position of the transmission element actuated by the adjusting element. Here, according to the present disclosure, it may be ensured that, although the adjusting element can move coaxially to the longitudinal central axis of the actuator and can rotate about this longitudinal central axis, a rotation of the magnet about this longitudinal central axis is prevented.

This solution of the present disclosure is provided an actuating device as described herein. Advantageous enhanced embodiments are defined further herein.

Accordingly, the present disclosure relates to an actuating device for an automated manual transmission of a motor vehicle, by which actuating device a selector element or shift element of the manual transmission is movable for setting a shift gate or for engaging or disengaging a gear, wherein the actuating device includes a pressure-medium-operated actuator having a piston and a piston rod, which is connectable to the selector element or shift element of the manual transmission, wherein the piston is arranged in a radially sealed manner in a cylindrical receiving chamber of the housing of the actuating device and is coaxially movable in the receiving chamber, wherein a sensor system that includes a magnet and a magnetic-field-sensitive sensor is provided, and wherein the magnet is arranged on the end face of the piston remote from the piston rod by way of a holding device and the sensor is arranged radially with respect to the magnet on the housing.

In order to provide the solution of the present disclosure, it is provided that the holding device is connected to the piston such that the piston is rotatable about the longitudinal central axis of the receiving chamber, that the holding device has a hollow cylindrical or a hollow-cylinder-segment-shaped geometry, that a rod-shaped or plate-shaped anti-rotation element is provided, which is form-lockingly accommodated at least with its two ends in an associated recess in the housing, and that the anti-rotation element extends through the hollow cylindrical or hollow-cylinder-segment-shaped holding device in the manner of a secant with slight play and spaced apart from the magnet, such that, although an axial movement and a rotational movement of the piston are possible, a rotational movement of the holding device about the longitudinal central axis of the receiving chamber is prevented.

Accordingly, a self-rotation of the holding device including the magnet arranged on the holding device about the longitudinal central axis of the cylindrical receiving chamber is reliably prevented by way of the anti-rotation element, such that the magnet is always aligned in a precisely positioned manner on the sensor element, which is arranged radially opposite. In addition, the axial displaceability of the holding device including the piston, which is carrying the holding device, is ensured due to the interaction of the holding device and the anti-rotation element, the interaction preferably having a slight amount of play.

The anti-rotation element preferably has a comparatively small overall size and can be cost-effectively manufactured without complex metal-cutting production steps and mounted in the housing of the actuating device. The preferably play-exhibiting arrangement of the anti-rotation element compensates for manufacturing tolerances and avoids the formation of temperature-induced mechanical stresses during operation. The anti-rotation element is also easily integrated into an existing structure by utilizing components that are already present. Moreover, a reduction of wear is also achievable by way of the anti-rotation element.

According to an advantageous embodiment of the actuating device, it is provided that the holding device has two axially extending longitudinal ribs, that the longitudinal ribs each have a planar bearing surface facing in the direction of the anti-rotation element, and that the bearing surfaces are arranged spaced apart from each other along an imaginary secant line of the holding device. The planar and narrow bearing surfaces of the longitudinal ribs effectuate only low frictional forces acting between the holding device and the anti-rotation element, such that a smooth axial displaceability of the holding device and of the piston of the actuating device is ensured.

Moreover, it is preferably provided that the housing of the actuating device is made up of a lower part and an upper part, which are sealed with respect to each other by way of a sealing element. The two-piece design of the housing enables a simple installation of the components of the actuating device.

According to another advantageous embodiment of the actuating device, it is provided that a wall of the lower part of the housing bounding the receiving chamber has at least one retaining pin, which is offset radially outward and points axially in the direction toward the upper part of the housing, that the anti-rotation element has at least one pocket at its side facing the lower part of the housing, and that each retaining pin is accommodated in one associated pocket and rests via the end face against the bottom of the pocket. As a result, a reliable securing-in-place of the anti-rotation element, in particular during its installation, is achieved. The at least one retaining pin preferably has a cylindrical geometry and the at least one pocket preferably has a cup-shaped geometry. A slight mechanical play, for example, is present between the pocket and the retaining pin.

The anti-rotation element preferably has a trapezoidal geometry. As a result, the anti-rotation element is easily and cost-effectively manufacturable. In addition, due to this geometry, a reliable seat of the anti-rotation element in the lower part of the housing of the actuating device is achieved.

Moreover, it is preferably provided that a base side of the anti-rotation element facing the holding device has an axially extending radial indentation, and that a contact surface directed toward the holding device is formed at the anti-rotation element on both sides next to this indentation. The bearing surfaces of the two longitudinal ribs of the holding device can be supported at these two contact surfaces. As a result, a minimization of the mechanical contact surface between the anti-rotation element and the holding device is achieved, as explained further below with reference to an exemplary embodiment.

The anti-rotation element is preferably form-lockingly arranged within a niche-like and approximately trapezoidal recess in the wall of the hollow cylindrical receiving chamber of the housing. As a result, a reliable accommodation of the anti-rotation element in the lateral wall of the housing is achieved.

Moreover, it is preferably provided that the two contact surfaces of the anti-rotation element have at least a slight amount of play and are positioned in parallel with respect to the particular bearing surfaces of the two longitudinal ribs of the holding device. The contact surfaces of the anti-rotation element extend substantially in parallel to the bearing surfaces of the holding device. As a result, a particularly low-friction axial movability and rotation prevention of the holding device for the magnets is achieved.

Preferably, the holding device and the anti-rotation element are made of the same material, such that possible wear debris is prevented from forming.

According to another advantageous embodiment of the present disclosure, it is provided that the sealing element is elastically designed and has at least two domes, which are integrally formed with the sealing element and oriented via their longitudinal extension in parallel to the longitudinal central axis. Despite the approximately knob-like domes, a reliable seal is ensured between the transmission housing and the upper part. The sealing element is preferably designed as a surface seal and made of an elastomeric plastic.

In addition, it can be advantageously provided that the axial length of the two domes of the sealing element is such that, in the mounted condition of the upper part and the lower part of the housing of the actuating device, the anti-rotation element is mechanically axially preloaded by way of these at least two domes against the at least one retaining pin of the lower part of the housing. As a result, the anti-rotation element is reliably prevented from moving, in particular, along with axial displacement movements of the holding device.

Another advantageous embodiment of the actuating device can be such that the at least two domes are connected with the sealing element and positioned by way of a plurality of webs integrally formed with the sealing element. As a result, a reduction of the number of parts of the actuating device and a simplified production and installation of the sealing element are achieved.

In order to implement an easily rotatable connection between the piston and the holding device, it is preferably provided that the holding device has a circular feed-through opening situated radially within, the feed-through opening being delimited in a wall-like manner by an annular shoulder of the holding device. The piston also has an annular collar radially within the holding device and remote from the piston rod, the annular collar extending axially toward the underside of a screw bolt inserted through the feed-through opening. The annular shoulder of the holding device is arranged in the annular open area formed as a result axially between the underside of the screw bolt and the collar of the piston with only a low clamping force.

In addition, it is provided that an axial position of the piston within the hollow cylindrical receiving chamber is contactlessly measurable by way of the sensor system. The aforementioned axial position is, for example, one of the two end positions and a central position in the actuating travel of the piston.

According to another advantageous embodiment of the actuating device, it is provided that the magnetic-field-sensitive sensor is arranged radially outside the wall bounding the hollow cylindrical receiving chamber. As a result, a sealed bore in the wall for accommodating the magnetic-field-sensitive sensor is not necessary.

DETAILED DESCRIPTION

FIG.1shows a partially cut perspective partial view of an actuating device10for an automated manual transmission12of a motor vehicle, the actuating device10including a holding device44for a magnet38, which is a component of a sensor system30. The actuating device10has a housing18that includes a lower part22, a cover-like upper part20, and a sealing element28arranged between the lower part22and the upper part20for fluidically sealing the housing18formed from the lower part22and the upper part20.

The actuating device10has at least one actuator54, which is operable by way of pressure medium and is designed as a piston-cylinder arrangement. By way of the final control element of the actuator54, a shift element or selector element of the manual transmission12is actuatable for selecting a shift gate or for engaging or disengaging a gear. This actuator54has a hollow cylindrical receiving chamber50in the lower part22of the housing18, in which receiving chamber50a piston58is arranged so as to be movable coaxially with the longitudinal central axis52of the receiving chamber50. The piston58is sealed radially outward by way of a circumferential piston seal60in a pressure-tight manner with respect to a wall106bounding the receiving chamber50. The piston58is preferably manufactured as a shaped sheet-metal part, which is extrusion-coated radially outward with a, for example, elastomeric plastic material for integrally forming the piston seal60.

A piston rod64is secured at the piston underside62facing away from the upper part20of the housing18. An interface68to the manual transmission12is formed at the free end66of the piston rod64. By way of the piston rod64, which is cylindrical in sections, for example, a selector rod (not represented) is connectable and the selector rod is actuatable for selecting a shift gate. The piston rod64can also be connected, however, to a gearshift shaft or shift fork of the manual transmission12, wherein the gearshift shaft or shift fork is utilized for displacing a gear shift sleeve associated with a gear wheel (not represented) along a transmission shaft. A gear ratio change of the automated manual transmission can be initiated by actuating the gear shift sleeve, as is known to a person skilled in the art from DE 10 2016 012 862 A1.

The aforementioned sensor system30is provided for ascertaining the current actuating position of the piston58, the sensor system30including, among other things, a magnetic-field-sensitive sensor32and a magnet38, which is contactlessly operatively connected to the sensor32. The magnetic-field-sensitive sensor32is, for example, a Hall sensor40in this case, which is connected by way of connection lines (not represented) to an electronic evaluation electronics system (also not represented) and to a control unit. The magnet38is constructionally integrated into the aforementioned holding device44, which, in this exemplary embodiment, has the circumferential geometry of a hollow cylinder segment. The holding device44can also have the geometry of a complete hollow cylinder, however. The holding device44is preferably made of a plastic material. The magnet38is preferably a permanent magnet46shaped as a segment of a circle, which is embedded as one piece into the plastic material of the holding device44.

By way of the sensor system30, the axial position X of the piston58along the longitudinal central axis52of the receiving chamber50and, thus, a current shift gate selector state or a shift condition of the manual transmission12, can be precisely determined. The magnetic-field-sensitive sensor32is positioned, by way of example in this case, radially opposite the magnet38, wherein the magnetic-field-sensitive sensor32is arranged radially outside a circumferential wall106of the hollow cylindrical receiving chamber50.

A permanently precise alignment of the magnetic-field-sensitive sensor32with respect to the magnet38integrated in the holding device44is important for ensuring proper measurements. In particular upon engagement of a gear, the piston rod64including the piston58and the holding device44secured at the piston58jointly tend to rotate, if not rotationally restricted, about the longitudinal central axis52, which is indicated inFIG.1by the circular first double arrow76. These rotational movements can adversely affect the measuring accuracy of the sensor system30. In order to prevent this undesirable effect, according to the present disclosure, a comparatively small anti-rotation element80is provided, which interacts with the holding device44in such a way that, although an unimpeded coaxial movement of the component assembly made up of the piston rod64, the piston58, and the holding device44is possible, a rotational movement of the holding device44carrying the magnet38is prevented in a low-friction manner.

FIG.2shows an axial top view of the lower part22of the housing18of the actuating device10including the sealing element28arranged between the upper part20and the lower part22of the housing18, the receiving chamber50of the housing18, the piston58arranged in the receiving chamber50, the holding device44, which is rotatably secured at the piston58remote from the piston rod, and the anti-rotation element80interacting with the holding device44.

The elastomeric sealing element28, readily apparent inFIG.2, rests against the lower part22of the housing18of the actuating device10. The holding device44is connected to the top side of the piston58remote from the piston rod so as to be rotatable, if not restricted, about the longitudinal central axis52of the receiving chamber50and arranged, at least in sections, in the receiving chamber50, which is bounded by the hollow cylindrical wall106of the lower part22. The holding device44has a first axially extending longitudinal rib90and a second axially extending longitudinal rib92, each of which has a planar bearing surface94,96, respectively, facing in the direction toward the anti-rotation element80. The two bearing surfaces94,96extend geometrically along an imaginary secant line98at the holding device44. This secant line98geometrically delimits the incomplete cylinder segment section of the holding device44.

The anti-rotation element80has a trapezoidal geometry, by way of example, wherein a base side110of the anti-rotation element80facing in the direction toward the holding device44includes a radial indentation112extending axially, i.e., perpendicularly to the plane of the drawing. A radially inward directed first contact surface114and a radially inward directed second contact surface116are formed next to the indentation112. The trapezoidal anti-rotation element80is arranged in this case in a niche-like recess120in the wall106of the lower part22of the housing18, the recess120being designed geometrically complementary to the anti-rotation element80and approximately trapezoidal.

The anti-rotation element80can be arranged in the recess120in a form-locking manner or with slight play at least in some areas. In the case of a design having slight play, production expenditure is reduced, since a machining operation of the aforementioned components can be dispensed with.

The two contact surfaces114,116of the anti-rotation element80are arranged preferably having at least a slight amount of play with respect to the bearing surfaces94,96of the two longitudinal ribs90,92. Consequently, clamping effects between the holding device44moving coaxially to the longitudinal central axis52and the anti-rotation element80are avoided.

The holding device44and the anti-rotation element80are preferably made of the same material, which can be, for example, a plastic material. As a result, material abrasion during the operation of the actuating device is largely avoided.

The sealing element28is elastically designed and can be made, for example, of an elastomeric plastic material. The sealing element28includes, by way of example in this case, two pin-like domes126,128, which are integrally formed with the sealing element28and oriented axially, i.e., perpendicularly to the plane of the drawing. The anti-rotation element80, in the completely mounted condition, is axially clamped between the upper part20and the lower part22of the housing18of the actuating device10by way of the two domes126,128. This is significant, in particular, for the case in which the anti-rotation element80is accommodated with play in the trapezoidal recess120. The at least two domes126,128are connected as one piece to the sealing element28with the aid of a plurality of webs130,132,134,136integrally formed at the sealing element28and, as a result, are precisely aligned.

Due to the anti-rotation element80resting against the secant line98of the holding device44in some areas, any self-rotation of the holding device44is ruled out. Because the holding device44is rotatably connected to the piston58, being rotatable relative thereto, the piston58can nevertheless rotate, due to the transmission, about its longitudinal axis or about the longitudinal central axis52during an axial movement, which is necessary for engaging a gear. Accordingly, the circumferential orientation of the holding device44shown inFIGS.1and2remains unchanged with respect to the sensor32under all operating conditions of the actuating device10, such that a precise determination of the axial position X of the piston58of the actuating device10can be carried out by way of the sensor system30.

FIG.3shows a longitudinal section along the section line A-A ofFIG.2. As a result, the receiving chamber50of the lower part22of the housing18of the actuating device10bounded by the wall106of the lower part22of the housing18is readily apparent. The piston58is accommodated in this receiving chamber50so as to be displaceable coaxially to the longitudinal central axis52and is guided in a manner sealed by way of the piston seal60, designed as a double-lip seal by way of example in this case. The seal between the lower part22and the upper part20of the housing18is implemented by way of the sealing element28, as described above.

The approximately hollow cylindrical or hollow-cylinder-segment-shaped holding device44including the magnet38integrated at the holding device44is arranged, at least in sections, in the receiving chamber50of the lower part22of the housing18and connected to the side of the piston58remote from the piston rod, such that the piston58is rotatable about the longitudinal central axis52. The piston58is fixedly connected to the piston rod64by way of a screw bolt142. The piston rod64includes, at its free end66directed away from the piston underside62, the interface68(readily apparent here) for an actuating element of the manual transmission12(not represented). This actuating element is, for example, a shift rail for engaging and disengaging gears.

The holding device44has a circular feed-through opening188situated radially inward, the feed-through opening188being delimited in a wall-like manner by an annular shoulder190of the holding device44. The shoulder190of the holding device44is arranged, with only a comparatively low clamping force, in an annular chamber between the underside of the screw bolt142and an annular collar192of the piston58. The collar192of the piston58is formed radially inward at the piston58and extends axially in the direction toward the underside of the screw bolt142without reaching the screw bolt142. The collar192is made, for example, of an elastomer injected onto the metal area of the piston58.

The clamping force with which the holding device44is held at the piston58is set, on the one hand, to be so great that the holding device44is carried along by the piston58without play during an axial movement of the piston58and, on the other hand, to be so low that the holding device44is fixedly held by the anti-rotation element80without damage during a rotational movement of the piston58, i.e., is prevented in a very low-friction manner from also rotating.

The receiving chamber50of the housing18is radially delimited by the circumferential, substantially hollow cylindrical wall106, as is also readily apparent in this case. The wall106includes, in the area of a bottom surface148of the aforementioned recess120and situated axially upward and at the top of the recess, at least one cylindrical retaining pin150, which is offset radially outward and points axially in the direction toward the upper part20. The anti-rotation element80is accommodated on this retaining pin150by way of an associated pocket152formed on the underside of the anti-rotation element80and, among other things, is secured in position as a result.

In the completely mounted condition of the upper part20and the lower part22of the housing18of the actuating device10represented inFIG.3, the anti-rotation element80is axially preloaded against the retaining pin150by way of the at least two domes126,128, of which only one dome128is visible inFIG.3. Consequently, in the case where the anti-rotation element80is accommodated with play in the recess120of the lower part22, the anti-rotation element80is reliably secured in position with respect to the axial movements of the component assembly made up of the piston58, the piston rod64, and the holding device44within the receiving chamber50coaxially to the longitudinal central axis52. Therefore, clamping and/or tilting effects, in particular between the anti-rotation element80and the holding device44for the magnet38, are ruled out.

In the case where a positive engagement (not represented here) exists, at least in some areas, between the anti-rotation element80and the recess120of the lower part22of the housing18of the actuating device10, an axial preload is not absolutely necessary between the retaining pin150of the lower part22and the upper part20of the housing18with the aid of the domes126,128of the sealing element28.

FIG.4shows a schematic, perspective representation of the holding device44and of the anti-rotation element80according toFIGS.1through3. It is also apparent here that the holding device44including the magnet38(which is not visible inFIG.4) is accommodated in the receiving chamber50of the lower part22of the housing18of the actuating device10and is displaceable axially to the longitudinal central axis52. The two bearing surfaces94,96of the holding device44, which rest against the two contact surfaces114,116of the anti-rotation element80with play to prevent the holding device44from rotating, are represented here in a simplified manner for the sake of greater drawing clarity as end faces164,166extending in parallel to each other. The trapezoidal anti-rotation element80is situated, only in areas, by way of example in this case, in a form-locking manner in a similarly trapezoidal recess120in the lower part22of the housing18of the actuating device10. In addition, the recess120in the wall106of the lower part22of the housing18includes, by way of example in this case, two projections160,162directed toward each other, which laterally reach over the end face166of the anti-rotation element80oriented in the direction toward the holding device44. Consequently, the anti-rotation element80cannot shift in parallel to the top side168of the lower part22of the housing18. Rather, the anti-rotation element80is largely form-lockingly accommodated in the aforementioned recess120.

FIG.5illustrates a cross-section (represented in a simplified manner) along the section line V-V ofFIG.4. The holding device44including the magnet38is accommodated in the receiving chamber50of the lower part22of the housing18axially to the longitudinal central axis52and coaxially to the direction of the second double arrow174. The receiving chamber50is closed by way of the upper part20of the housing18. The anti-rotation element80is accommodated with play in the recess120of the lower part22of the housing18and, thus, can shift at least slightly in parallel to the top side168of the lower part22of the housing18. In order to prevent this parallel displaceability, the anti-rotation element80is axially clamped between the upper part20and the bottom surface148of the recess120in the lower part22of the housing18with the aid of the only one visible pin-shaped dome128as a component of the sealing element28. As a result, a reliable securing-in-place of the anti-rotation element80in the recess120is ensured also during axial movements of the holding device44within the receiving chamber50.

FIG.6shows a schematic representation of the forces acting on the holding device44and the anti-rotation element80according toFIG.5. The anti-rotation element80arranged here in a manner with play is apparent between the upper part20and the lower part22of the housing18and axially clamped by way of the one visible dome128(dome126not visible in this view) of the sealing element28. The holding device44including the magnet38, which is arranged on the holding device44and is completely extrusion-coated with plastic, strives to rotate together with the piston58and the piston rod64, counter to the effect of the anti-rotation element80, about the longitudinal central axis52according to the rotation arrow180. In addition, as indicated by the third double arrow182, the holding device44carries out axial movements coaxially to the longitudinal central axis52. As presented in a simplified manner, a first contact point P1, in the area of which the first sliding friction μ1prevails, exists between the holding device44and the anti-rotation element80. In addition, as presented in a simplified manner, a second contact point P2exists between the dome128and the anti-rotation element80, wherein a second sliding friction μ2prevails in this area between the dome128and the anti-rotation element80. Finally, as presented in a simplified manner, a fulcrum PA, about which the anti-rotation element80could tilt, exists between the anti-rotation element80and the lower part22of the housing18. Due to the axial movement of the holding device44, the anti-rotation element80strives to move upward or downward in the direction of a fourth double arrow184, which results in a compression movement of the elastic dome128in the direction of the fifth double arrow186.

Upon contact with the anti-rotation element80, the holding device44acts with a horizontal force F1oriented perpendicularly to the longitudinal central axis52on the anti-rotation element80, such that an opposite and equal counter forceTacts at the first contact point P1. The upper part20of the housing18presses with a normal force NCacting parallel to the longitudinal central axis52on the dome128of the sealing element28, which induces an equal and oppositely directed normal reaction force RC1there. A compressive force RC2is imparted as a result via the dome128of the sealing element28, the compressive force RC2acting at the point P2perpendicularly onto the anti-rotation element80and, with respect to its absolute value, is equal to the normal force NC.

An undesirable tilting force Fxarising due to the upwardly and downwardly directed axial movements of the holding device44is defined as Fx=F1*μ1, which is therefore proportional to the magnitude of the horizontal force F1and the sliding friction μ1between the holding device44and the anti-rotation element80.

A first lever length “a” exists between the first contact point P1and the second contact point P2,and a second lever length “b” extends between the second contact point P2and the fulcrum PA. The inequality Fx(a+b)<RC2*b must be satisfied in order to ensure that an anti-rotation element80that is accommodated in the recess120of the lower part22of the housing18with play is also reliably secured in position despite the axial movements of the holding device44. This means that a torque formed from the product of the tilting force Fxand the sum of the two lever lengths a+b must always be less than the torque formed from the product of the compressive force RC2or the normal force NCwith the second lever length b. Thus, the compressive force RC2built up by the dome128, by the upper part20, and by the lower part22of the housing18and acting on the anti-rotation element80must always be greater than the tilting force Fx.

The compliance with the inequality can be substantially ensured by way of an appropriate material section for setting the two sliding frictions μ1, μ2, by way of the selection of an elastomeric plastic having a suitable elasticity for the at least one dome128, and by way of an appropriate axial mechanical clamping or preloading of the dome128.

LIST OF REFERENCE CHARACTERS

10actuating device for an automated manual transmission12automated manual transmission18housing of the actuating device20upper part of the housing22lower part of the housing28sealing element30sensor system32magnetic-field-sensitive sensor38magnet40Hall sensor44holding device for the magnet46permanent magnet50receiving chamber in the lower part of the housing52longitudinal central axis54actuator58piston60piston seal62piston underside64piston rod66free end of the piston rod68interface76first double arrow80anti-rotation element90first axial longitudinal rib of the holding device92second axial longitudinal rib of the holding device94first bearing surface of the holding device96second bearing surface of the holding device98secant line of the holding device106wall of the receiving chamber110base side of the anti-rotation element112indentation in the anti-rotation element114first contact surface of the anti-rotation element116second contact surface of the anti-rotation element120recess in the lower part of the housing126first dome128second dome130first web132second web134third web136fourth web142screw bolt148bottom surface of the recess150retaining pin152pocket in the anti-rotation element160first projection162second projection164end face of the holding device166end face of the anti-rotation element168top side of the lower part of the housing174second double arrow180rotation arrow182third double arrow184fourth double arrow186fifth double arrow188feed-through opening of the holding device190annular shoulder of the holding device192annular collar of the pistona first lever lengthb second lever lengthNCnormal forceRC1reaction force (normal force)RC2compressive forceF1horizontal forceFTcounter forceFXtilting forceP1first contact pointP2second contact pointPAfulcrumμ1first sliding frictionμ2second sliding frictionX axial position of the piston