EP2208244A1

EP2208244A1 - Pieozoelectric drive device

Info

Publication number: EP2208244A1
Application number: EP08804090A
Authority: EP
Inventors: Walter Haussecker; Vincent Rieger; Volker Rischmueller; Peter Froehlich
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 2007-11-02
Filing date: 2008-09-12
Publication date: 2010-07-21
Also published as: US20110006640A1; WO2009056384A1; DE102007052494A1

Abstract

The invention relates to a piezoelectric drive device for adjusting movable parts (11), particularly in a motor vehicle, having a piezomotor (12) having at least one piezoactuator comprising an electric piezoelement, wherein at least one friction element (30) is disposed on the piezomotor (12), said element interacting with a friction surface (14) of at least one guide rail (16) opposite said friction element (30) for creating a relative movement, wherein the friction surface is positioned opposite of the friction element (30), wherein the at least one piezomotor (12) is supported on a first side (94) of a bearing bracket (8) and a counter element (98) is disposed on a second opposite side (95) of the bearing bracket (8), which exerts a counter force (97) to the friction element (30) onto the at least one guide rail (16).

Description

title

Piezoelectric drive device

State of the art

The invention is based on a piezoelectric drive device for adjusting moving parts according to the preamble of the independent claim.

With the EP 01712170 Bl a piezoelectric motor unit has become known with which a window can be raised or lowered. In this case, for example, a vertically extending extension is attached to a window pane, on whose opposite sides a piezoelectric motor unit is applied. The two piezoelectric drive units are each mounted separately stationary, with a vibration of the piezoelectric motor units is permitted by a resilient mounting.

A disadvantage of such fixings of the piezomotors is the relatively large tolerance chain, whereby the frictional contact between the friction elements and the vertical extension can be influenced unpredictably. This effect is amplified by vibrations of the motor vehicle door, which can be locally formed differently strong.

Disclosure of the invention

Advantages of the invention

The piezoelectric drive device according to the invention with the features of the independent claim has the advantage that is always ensured by the storage of at least one piezo motor in a bearing bracket a defined contact pressure of the friction against the friction surface of the guide rail. This is realized in that the bearing bracket is designed such that preferably opposite to the friction element by the bearing bracket a constant counterforce is exerted, whereby the frictional contact between the friction element and the friction surface is independent of inhomogeneous vibrations of the vehicle side door. The measures listed in the dependent claims advantageous refinements and improvements of the embodiments specified in the dependent claim are possible. Thus, for example, the counterforce for the first friction element is applied by the arrangement of an opposite piezomotor, which also with a friction element from the opposite side to a

Guide rail presses. For this purpose, designed as a counter element second piezo motor is connected via the rigid bearing bracket with the first piezo motor.

In a further embodiment, the counter element is designed as a pressure element, which preferably exerts an approximately point-like counter-force to the friction element of the first piezo motor on one of the two guide rails. For this purpose, the bearing bracket surrounds the one or the two guide rails, wherein the pressure element is preferably formed as a rigid end of the bearing bracket on the opposite side of the first piezoelectric motor.

For adjusting the movable part, the at least one piezomotor executes a relative movement to the guide rail, wherein the guide rail can be designed according to the adjustment as a straight line or as a plurality of straight line sections or arcuate. When using two or more guide rails, these run approximately parallel to each other.

Preferably, the abutment region of the first piezo motor is arranged exactly opposite to the counter abutment region of the counter element of the bearing bracket, wherein the abutment / counter abutment regions are for example approximately punctiform. In an alternative embodiment, the touch point and the

Gegenanlagepunkt but also be offset from each other to thereby influence the power transmission of the friction element on the friction surface.

Attacks the counter element on the same guide rail as the friction element of the first piezo motor, the bearing bracket can be made relatively short, resulting in a relatively rigid clamping of the friction element with the counter element, whereby the power transmission between the friction element and the friction surface is less prone to failure.

Surrounds the bearing bracket two guide rails, the longer trained bearing bracket is somewhat susceptible to vibration, however, so can be decoupled from the vibrations of the body a greater distance between the point of contact of the first friction element and the contact point of the counter element. The first piezomotor and possibly also the other piezomotors are advantageously arranged resiliently in corresponding receptacles of the bearing bracket, such that the springs exert a predetermined contact pressure of the friction elements on the corresponding friction surfaces.

It is particularly favorable when the at least one piezomotor is firmly connected to the side door of the motor vehicle via the bearing bracket, and then the at least one guide rail, which is arranged on the movable part, moves relative to the at least one piezomotor. In this embodiment, the electrical supply of the piezo motors can be rigid and stationary.

In an alternative embodiment, the at least one guide rail is stationary, preferably fixed to the side door and the bearing bracket with the at least one piezomotor is fixed to the movable part - preferably the window pane - fixed. The fixed arrangement of the at least one guide rail space in the adjustment direction can be saved, since then the movable part can overlap with the bearing bracket with the guide rail.

It is particularly advantageous when the bearing bracket is approximately point-shaped attached to a single attachment point, for example on the body or on the movable part to decouple the power transmission of the friction elements as possible from external interference. Alternatively, two attachment points can be provided with which the bearing bracket can be reliably fixed to the window pane. It is advantageous to arrange the attachment points symmetrically to the bearing bracket.

The bearing bracket of the piezoelectric drive according to the invention is suitable, depending on the requirements of the adjusting and the available space either exactly one or two or three or four piezo motors to store in a single bearing bracket.

As a result, a very small tolerance chain with respect to the single friction elements and the corresponding friction surfaces can be achieved. Without major structural changes while individual piezo motors can be replaced by pressure elements to apply the corresponding counterforce.

For storage of the at least one piezoelectric motor in recordings of the bearing bracket of the piezoelectric motor is preferably stored in the vibration node of the piezoelectric actuator. This has the advantage that by the storage at the locations of the piezoelectric actuator, in which the Vibration amplitude is zero, the damping of the mechanical actuator vibration is minimized, whereby their efficiency is significantly increased. The mechanical fixation of the piezo motors in the bearing bracket is adapted to the electrical excitation of the piezo elements, which is preferably possible by a single-phase excitation of the piezo actuators.

If the piezoactuator is vibrated exclusively in the longitudinal direction, a nodal plane is formed which is aligned essentially perpendicular to the longitudinal direction and cuts the actuator housing in a peripheral line. In this vibration node, the piezoelectric actuator can be advantageously fixed rigidly over its entire circumference along the circumferential line, whereby a very stable storage is achieved. It is advantageous to form a recess or an extension in the transverse direction to the longitudinal direction on the surface of the housing for storage in the receptacle of the bearing bracket directly on the actuator housing in the vibration node. Depending on the shape of the vibration node, the extension in the transverse direction may be more punctiform or annular, wherein in the presence of a nodal plane, the extension can be received at arbitrary points along the circumference of the layer element. Alternatively, the receptacle is formed as a groove, in particular as an annular groove, whose axial extent is ideally concentrated as possible on the nodal plane. By clamping the extension in the transverse direction between two mounting plates designed as mounting manufacturing tolerances can be compensated very easily and a very high rigidity of the bearing elements can be achieved by the bracing of the two plates, which is higher than the stiffness of the piezoelectric actuators. The mounting plates can be arranged approximately parallel to the bridge web. In one embodiment of the invention, exactly two piezoelectric actuators are arranged approximately parallel to one another, wherein the bridge web is arranged approximately parallel to the mounting plates, between which the receptacles are clamped. In this embodiment, the friction element can be placed on the bridge bridge either by one of the two piezo actuators or by a common excitation of the two piezo actuators in a shock or an ellipse movement. For example, the bearing bracket for a window lift drive in the motor vehicle can be attached to a window pane. The direct generation of a linear motion enables a very fast response time with high dynamics. Due to the micro-shock principle, an extremely precise positioning of the part to be adjusted can be achieved with low noise emission.

Embodiments of the invention are illustrated in the drawings and explained in more detail in the following description. Show it 1 is a piezoelectric drive device according to the invention,

2 is a schematic representation for operating the drive device,

3 to 7 different embodiments of the piezomotor bearing, and Fig. 8 shows several variants of guide rails.

In Fig. 1, a piezoelectric drive device 10 is shown, in which a piezoelectric motor 12 performs a relative movement relative to a corresponding friction surface 14. The friction surface 14 is in this case formed as a linear rail 16, which is fastened for example to a body part 17. The piezomotor 12 has at least one piezoelectric actuator 18, which in turn contains a piezoelectric element 20. For this purpose, the piezoelectric actuator 18 a

Actuator housing 22 which receives the piezoelectric element 20. The actuator housing 22 is formed, for example, sleeve-shaped. In the illustrated embodiments, the piezoelectric element 20 is enclosed by the actuator housing 22. The piezoelectric actuator 18 has a longitudinal direction 19 in the direction of which the expansions of the piezoactuator 18 are greater than in a transverse direction 24. The piezoelectric element 20 is preferably biased in the actuator housing 22 in the longitudinal direction 19, such that upon excitation of a longitudinal vibration 26 of the piezoelectric element 20 in this no tensile forces occur. Due to the vibration of the piezoelectric element 20, the entire piezoelectric actuator 18 is set in longitudinal vibration 26 and transmits a vibration amplitude 45 via a bridging web 28 to a friction element 30 which is in frictional contact with the friction surface 14. By the

Longitudinal vibration 26 of the piezoelectric actuator 18, the bridge web 28 is set in a tilting movement or a bending movement, so that one of the friction surface 14 facing end 31 of the friction element 30 performs a micro-shock movement. The interaction between the friction element 30 and the friction surface 14 is shown in the enlarged section, in which it can be seen that the bridging web 28, which is arranged in the rest position approximately parallel to the friction surface 14, tilted with respect to the friction surface 14 at the excited vibration of the piezoelectric actuator 18. In this case, the end 31 of the friction element 30 performs, for example, approximately an elliptical movement 32 or circular movement, by means of which the piezomotor 12 abuts along the linear rail 16. The piezomotor 12 is in the region of a vibration node 34 of the

Stored piezo actuators 18 and connected for example by means of a bearing bracket 8 (only partially shown) with a part 11 to be reorganized. The vibration node 34 is formed in the longitudinal vibration 26 of the piezoelectric actuator 18 as a node plane 111, which extends approximately perpendicular to the longitudinal direction 19. The piezoelectric actuator 18 is received on an outer circumferential line 112, which is formed by the section of the account level 111 by the piezoelectric actuator 18 of a receptacle 36 of the bearing bracket 8. The vibration node 34 is determined for this purpose by means of simulation and / or empirically. At the same time, the piezo motor 12 via a bearing bracket 8 with a normal force 37 pressed against the friction surface 14. As a result, the end 31 of the friction element 30 now executes an elliptical movement 32 which, in addition to the normal force 37, has a tangential force component 38 which causes the piezomotor 12 to advance with respect to the friction surface 14. In an alternative embodiment, the friction element 30 performs only a linear pushing movement at a certain angle to the normal force 37. This also leads to a relative movement by means of micro-collisions.

In the exemplary embodiment according to FIG. 1, the piezomotor 12 has exactly two piezoactuators 18, which are both arranged approximately parallel to their longitudinal direction 19. Here, the bridge web 28 is arranged transversely to the longitudinal direction 19 and connects the two piezo actuators 18 at their end faces 27. In this case, the bridge web can also be made in one piece with the actuator housings 22. The bridge web 28 is formed for example as a flat plate 29, in the middle of the friction element 30 is arranged. In a preferred mode of operation of the piezoelectric drive device 10, only one of the two piezoactuators 18 is excited for a relative movement in a first direction 13. In this case, the second, non-excited piezoactuator 18 acts via the bridging web 28 as an oscillating mass, due to which the bridging web 28 is tilted or bent with the friction element 30 with respect to the longitudinal direction 19. In accordance with the rigidity of the structure of the piezo motor 12, the longitudinal vibration 26 of the piezoelectric element 20 is thus converted into a micro-impact movement with a tangential force component 38. The electrical excitation of the piezoelectric element 20 via electrodes 40, which are connected via a contact element 41 with an electronic unit 42. For a movement of the piezo motor 12 in the opposite directions 15, the piezoelectric element 20 of the other piezoelectric actuator 18 is excited accordingly by means of the electronic unit 42. In this mode of operation, only one piezoelectric element 20 of the piezoelectric motor 12 is always excited, so that there can be no superimposition of two oscillatory excitations of the two piezoelectric actuators 18.

The piezoelectric drive device 10 is operated at its resonance frequency, for example. For this purpose, the electronic unit 42 has a tuning circuit 46, which controls the corresponding piezoelectric element 20 in such a way that the entire system oscillates in resonance. The electronic unit 42 may be arranged, for example, at least partially within the actuator housing 18 or the bearing 36. In FIG. 1, the amplitudes 45 of the resonance frequency of the longitudinal vibration 26 are shown in the two piezoactuators 18. The maximum amplitudes 45 correspond here to the mechanical resonance frequency. In Fig. 2, a model of the piezoelectric driving device 10 is shown, which serves as a basis for adjusting the resonance frequency. In this case, the piezoelectric actuator 18 is shown as a resonant circuit 52, in which an inductance 53 with a first capacitor 54 and a resistive load 55 are connected in series. For this purpose, a second capacitance 56 is connected in parallel. At this oscillation circuit 52, an excitation voltage 43 is applied by means of the electronic unit 42. Furthermore, the resonance frequency of the entire drive device 10 depends on the load 58, which is determined for example by the weight of the part 11 to be adjusted and / or the friction condition between the friction element 30 and the friction surface 14, which is schematically represented by the mechanical power transmission 57.

FIG. 3 shows a further embodiment of a piezoelectric drive device 10 according to the invention, in which, for example, a piezomotor 12 according to FIG. 1 or a piezo motor 12 designed in any other way is used. The guide rail 16 is fixedly arranged, for example, attached to a side door 7 as a body part 17. As a movable part 11, a window pane 9 is adjusted along the guide rail 16. With the movable part 11 of the bearing bracket 8 is firmly connected, for example via a single attachment point 90 which is arranged approximately centrally in the window pane 9. The bearing bracket 8 has on a first side 94 a receptacle 36, in which the piezoelectric motor 12 is preferably fixed to the vibration node 34 of the piezoelectric actuator 18 (see, for example, Fig. 1). The piezomotor 12 is pressed by the bearing bracket 8 by means of a spring element 96 against the guide rail 16, so that the friction element 30 is in sufficient frictional contact with the friction surface 14. For applying a counterforce 97 (to the normal force 37), a counter element 98 is arranged on the bearing bracket 8 on the second side 95 as a pressure element 93, which abuts against a rear side 99 of the guide rail 16. In this case, the contact point 100 of the counter element 99 is arranged opposite to the contact point 101 of the friction element 30, so that these two are approximately in a line along the longitudinal direction 19 of the piezoelectric actuator 18. The contact point 101 and the contact point 100 are approximately point-shaped, but may also have a linear or planar extension. The pressure element 93 is formed, for example, as plain bearings, roller bearings or other guide surfaces with more or less extended contact points 100. The bearing bracket 8 is connected in this example on the second side 95 with the movable part 11, the attachment point 90 may alternatively be arranged symmetrically in the middle of the bearing bracket 8 (see Fig. 4).

In a variation of this embodiment, the counter element 98 on the second side 95 of the bearing bracket is likewise designed as a piezomotor 12 in FIG. 4. This one is also in a receptacle 36 and acts instead of the pressure element 93, a counter force 97 on the friction element 30 of the first piezo motor 12 from. In this case, both friction elements 30 of the two piezo motors 12 extend approximately along a line, preferably the longitudinal direction 19 of the piezoelectric actuators 18. acting as a counter element 98 second piezoelectric motor 12 is not resiliently mounted in the receptacle 36 in this embodiment, so that the mutual contact force of the two Friction elements 30 is predetermined solely by the one spring element 96. In this case, the bearing bracket 8 is mounted approximately centrally on the part 11 to be adjusted

In a further embodiment of the drive device 10 according to the invention, which is shown in Fig. 5, two guide rails 16 are arranged stationary, which extend approximately parallel. Such a design is preferred when the part 11 to be adjusted exceeds a certain size. The bearing bracket 8 is fixed to the movable part 11, for example symmetrically by means of two attachment points 90. In this embodiment, the bearing bracket 8 extends over the entire space 102 between the two guide rails 16 and surrounds the latter such that the contact pressure 37, which on the front of the the first guide rail 16 is applied, counteracts a counter force 97 which acts on the rear side 99 of the second guide rail 16 facing away from the first guide rail 16. The counter element 98 is designed here as a piezomotor 12, so that the two friction elements 30 are approximately arranged in a line along the longitudinal direction 19 and abut the two, facing away from each other friction surfaces of two different guide rails 16. Here, both piezo motors 12 are mounted in their receptacles 36 each with spring elements 96, whereby a better tolerance compensation takes place.

In a variation of this embodiment, one or two additional pressing elements 93 can additionally be arranged (shown in dashed lines), which lie directly opposite the respective friction elements 30 on the respective guide rails 16. As a result, the contact pressure of the two friction elements 30 is additionally stabilized.

In Fig. 6, a further embodiment is shown, which differs from the embodiment of FIG. 3, that here the guide rail 16 is fixedly connected to the part to be adjusted 11, and moves together with this relative to the stationary mounted piezoelectric motor. For this purpose, the bearing bracket 8, for example, firmly connected to the body part 17. For this purpose, the bearing bracket on an attachment point 90 in the central region of the bracket on which the bearing bracket 8 is fixed to the side door. Since the guide rail 16 moves in this embodiment, sufficient space must be present for lowering the guide rail (16). In this embodiment, the contact point 100 of the counter element 98 has an offset 103 to the contact point 101 of the friction element of the first piezo motor 12. This offset 103 along the direction of movement 13, 15 may cause an additional tangential force component in the power transmission through the friction element 30 on the friction surface 14. Such offset 103 can be realized even when using a second piezo motor 12 as a counter element 98.

FIG. 7 shows an analogous embodiment to the drive device according to FIG. 5, in which two guide rails 16 are fastened to a (common) movable part 11. The two guide rails 16 can be adjusted together with the movable part 11 relative to the stationary bearing bracket 8. As a counter element 98, in turn, a second piezo motor 12 is provided so that rest according to the embodiment in Fig. 5 again two friction elements 30 on the two outer friction surfaces 14 of two different guide rails 16. The bearing bracket 8 is attached approximately centrally in the body part 17, so that the entire bearing bracket 8 is formed symmetrically at the attachment point 90. Again, in a variation additional pressing elements 93 can be arranged according to FIG. 5, in order to ensure a constant contact force 37.

In one embodiment, not shown in detail, the guide rails 16 are formed as part of the movable part 11, for example, as lateral edges of the window pane 9. This results in the formed as a vehicle door 7 body part 17, a particularly large central area as a free space 6, for installation large-volume components, such as airbags of the speakers, can be used.

In a further embodiment according to FIG. 8, the two guide rails 16 are not formed as continuous straight lines 104, but have bend-off straight line sections 105, which again run approximately parallel. On the left side, the embodiment for two parallel straight lines 104 is indicated by dashed lines as guide rails 16, as described for example in FIG. 5. As a further variation, an arcuate guide rail 106 is shown by dashed lines on the right side in dashed lines, to which also preferably a second arcuate guide rail 106 extends approximately parallel. The guide rails 104, 105, 106 are designed, for example, stationary, so that the movable part 11 with the piezomotors 12 arranged thereon can be displaced along the guide rails 104, 105, 106. On the right side, a first piezomotor 12 is connected via a first bearing bracket 8 to a counter element 90 designed as a second piezo motor 12. The bearing bracket 8 is by means of Fixing point 90 connected by a further fastening device 107 with the movable part 11. On the left side, a second bearing bracket 8 is arranged, which also receives two opposing piezo motors 12.

It should be noted that with regard to the exemplary embodiments shown in the figures and in the description, a variety of possible combinations of the individual features are possible with one another. Thus, for example, the specific design of the piezoelectric motors 18, the actuator housing 22, the piezoelectric elements 20 and the friction element 30 can be varied according to the application. In this case, the plunger movement may be formed as a pure shock movement or as a substantially elliptical or circular trajectory, wherein according to the transverse component of the power transmission, the friction pair between the friction member 30 and the friction surface 14 has a higher or lower coefficient of friction. In this case, the pure linear plunger movement is the limiting case of the ellipse movement. As a borderline case, a design with a pure positive connection is possible, in which the friction element 30 without

Friction in a corresponding recess, for example in a micro-toothing of the drive element, e.g. the guide rail 16 engages. All piezomotors 18 can be accommodated in a single common bearing bracket 8, or be fastened individually in several bearing brackets 8. The specific embodiment of the receptacles 36 is dependent on the shape of the actuator housing 22 and the excited waveform. The drive unit 10 according to the invention is preferably used for adjusting moving parts 11 (seat parts, window panes, roof, flaps) in the motor vehicle, but is not limited to such an application.

Claims

claims

1. Piezoelectric drive device (10) for adjusting moving parts (11), in particular in the motor vehicle, with a piezoelectric motor (12) having at least one piezoelectric actuator (18) with an electric piezoelectric element (20), wherein at the piezoelectric motor (12) at least a friction element (30) is arranged which cooperates with at least one guide rail (16) to produce a relative movement with a friction surface (14) opposite the friction element (30), characterized in that the at least one piezo motor (12) is arranged on a first side ( 94) of a bearing bracket (8) is mounted, and on a second opposite side (95) of the bearing bracket (8) a counter element (98) is arranged, the a counter-force (97) to the friction element (30) on the at least one guide rail (16 ) exercises.

2. Piezoelectric drive device (10) according to claim 1, characterized in that the counter element (98) as a further piezomotor (20) with a friction element (30) is formed.

3. Piezoelectric drive device (10) according to any one of claims 1 or 2, characterized in that the counter-element (98) as rigid with the bearing bracket (8) connected pressure element (93) is formed.

4. Piezoelectric drive device (10) according to any one of the preceding claims, characterized in that the at least one guide rail (16) is bent or straight or formed as a bent straight line sections (105).

5. Piezoelectric drive device (10) according to any one of the preceding claims, characterized in that an abutment point (101) of the friction element (30) of the at least one piezoelectric motor (20) and a counter contact point (100) of the counter element (98) approximately in a single plane are arranged transversely to the relative movement or with an offset (103) with respect to the direction of movement (13, 15) of the part (11) are arranged.

6. Piezoelectric drive device (10) according to one of the preceding claims, characterized in that the counter element (98) rests against the same guide rail (16) as the friction element (30) of the at least one piezoelectric motor (12), in particular on the rear side (99) of the guide rail (16) opposite the friction surface (14).

7. Piezoelectric drive device (10) according to any one of the preceding claims, characterized in that the counter element (98) at a second

Guide rail (16) is applied, which is approximately parallel to the guide rail (16) is arranged on the friction element (30) of the at least one piezoelectric motor (12), in particular on one of the friction surface (14) opposite the rear side (99) of the second guide rail (16 ).

8. Piezoelectric drive device (10) according to any one of the preceding claims, characterized in that the at least one piezoelectric motor (12) and / or the counter element (98) each in a receptacle (36) of the bearing bracket (8) by means of a spring (96) are mounted, which generates a biasing force (37), with which the at least one piezoelectric motor (12) and / or the counter element (98) substantially transversely to

Movement direction (13, 15) of the part (11) against the at least one guide rail (16) are pressed.

9. Piezoelectric drive device (10) according to any one of the preceding claims, characterized in that the bearing bracket (8) is arranged stationary, in particular fixed to a body part (17) - for example, a vehicle door (7) - is fixed, and the guide rail (16 ) is arranged displaceably.

10. Piezoelectric drive device (10) according to any one of the preceding claims, characterized in that the bearing bracket (8) on the movable part (11) is fixed and the guide rail (16) is arranged stationary, in particular fixedly attached to a body part (17) ,

11. Piezoelectric drive device (10) according to any one of the preceding claims, characterized in that the bearing bracket (8) on a single or two

Attachment points (90) on the movable part (11) or on the body part (17) is attached.

12. Piezoelectric drive device (10) according to any one of the preceding claims, characterized in that in the formation of a single attachment point

(90) of this approximately centrally with respect to the plane transverse to the relative movement - in particular for fixing to the body part (17) - is arranged.

13. Piezoelectric drive device (10) according to any one of the preceding claims, characterized in that on a single bearing bracket (8) exactly one, two, three or four piezo motors (12) are mounted, each cooperating with friction surfaces (14), the a front side and / or the back (99) of exactly one or exactly two guide rails (16) are arranged.

14. Piezoelectric drive device (10) according to one of the preceding claims, characterized in that the at least one piezoelectric actuator (18) of the at least one piezoelectric motor (20) in the region of a vibration node (34) (amplitude zero point) of the excited piezoelectric actuator vibration directly or indirectly the bearing bracket (8) is fixed.

15. Piezoelectric drive device (10) according to one of the preceding claims, characterized in that the at least one guide rail (16) integral part of the movable part (H) - in particular a window pane (9) - is.

16. Piezoelectric drive device (10) according to any one of the preceding claims, characterized in that the at least one piezoelectric motor (20) and the at least one guide rail (16) outside a central region with respect to the window pane (9) in the vehicle door (7) are arranged such that a free one

Space 0 "for example, for installation of airbags or speakers - in the central region of the vehicle door (7) is available.