Electromechanical spindle drive, method for operating an aforementioned spindle drive, and positioning device comprising a spindle drive

Abstract

The invention relates to an electromechanical spindle drive (1) comprising: a threaded spindle (2) having an external thread and a spindle axis (SA); at least two drive units (3) which are spaced apart from one another with respect to the spindle axis (SA), each of the drive units (3) having an elastically deformable frame body (4) which comprises two receiving spaces (40), into each of which an electromechanical actuator (6) is inserted; a connecting device (7) for mechanically connecting the drive units (3), wherein each of the frame bodies (4) has a receiving portion (42) for the threaded spindle (2), which receiving portion has two drive portions (44) integrally formed with the frame body (4), said drive portions contacting opposite peripheral portions of the external thread of the threaded spindle (2) and being displaced, by applying suitable electrical signals to the electromechanical actuators (6), through a deformation of the frame body (4) thereby induced. The invention is characterised by the provision of a solid lubricant element (8) which is arranged between adjacent drive units (3) in such a manner that it at least partially surrounds the threaded spindle (2) and is in contact therewith. The invention also relates to a method for operating an aforementioned spindle drive, and to a positioning device comprising such a spindle drive.

Description

Electromechanical spindle drive, method for operating a aforementioned spindle drive, and a positioning device with a spindle drive

[0001] Background of the invention

[0002] The invention relates to an electromechanical spindle drive, a method for operating such a spindle drive, and a positioning device with such a spindle drive.

[0003] German patent DE 102021 113 751 A1 discloses a generic spindle drive in which a threaded spindle received in a spindle chamber of a frame device is set into a rotary motion by means of two actuator devices, which, according to one of the embodiments shown therein, move an actuating device that partially surrounds the spindle and is in thread contact with it, and simultaneously provide for a deformation supporting the drive movement of a section of a frame device that partially surrounds the threaded spindle on the opposite side and is also in thread contact with it there, which is converted into a linear motion of the threaded spindle due to the thread engagement.In other embodiments disclosed in DE 10 2021 113 751 A1, the two actuator devices each act directly on a drive element which is partially engaged with the threaded spindle on opposite sides and which is part or section of a frame device surrounding the threaded spindle or is connected to it, wherein the actuator devices are controlled in such a way that the deformations achieved thereby are opposite in direction and thus cause a rotational movement of the threaded spindle.

[0004] A certain disadvantage here is that the respective spindle drive has a complex or relatively difficult-to-handle design in terms of assembly, and is also not suitable for use at low temperatures.

[0005] From DE 102022 113 382 B3 of the applicant, a generic spindle drive is known in which contact elements are in thread engagement with a threaded spindle to be driven and are fixed to a base element, The components, which are also mechanically connected to each other, are moved in opposite directions via piezoelectric actuators in contact with them to generate a rotary movement of the threaded spindle. This spindle drive is also comparatively complex and only conditionally suitable for low to very low temperatures.

[0006] Objectives of the invention

[0007] It is an object of the invention to provide an electromechanical spindle drive as an alternative to known electromechanical spindle drives. In particular, it is an object of the invention to provide an electromechanical spindle drive that, with a simple structure that is easy to assemble, allows use down to extremely low temperatures, i.e., under cryogenic conditions. In particular, a further object of the invention is to provide an electromechanical spindle drive that has a relatively simple and, in particular, relatively easy-to-assemble design. In particular, it is a further object of the invention to provide an electromechanical spindle drive that can be used at low temperatures. A further object of the invention is to provide a positioning device with an electromechanical spindle drive according to the invention.Another object of the invention is to provide a method for operating an electromechanical spindle drive according to the invention.

[0008] Inventive solutions

[0009] The aforementioned problem relating to an electromechanical spindle drive can be solved, for example, with an electromechanical spindle drive that optionally comprises a threaded spindle with a spindle axis, two drive units engaged with or in contact with the threaded spindle and mechanically connected to one another via a connecting device, and in particular spaced apart from one another in the direction of the spindle axis, each of which comprises at least two electromechanical actuators, and a solid lubricant element arranged between the drive units. It is conceivable that the electromechanical spindle drive according to the invention comprises more than two drive units, of which two adjacent drive units form a pair of drive units, wherein at least One of the drive unit pairs has a solid lubricant element arranged between its two drive units, and at least one of the drive unit pairs has a connecting device connecting its two drive units to each other. The electromechanical spindle drive according to the invention has a threaded spindle with a spindle axis if a respective section of the threaded spindle can be inserted into a spindle chamber formed in each of the frame bodies. Accordingly, an electromechanical spindle drive with a spindle chamber in each of the frame bodies, but without a threaded spindle, is also provided according to the invention.

[0010] By providing a solid lubricant element positioned along the spindle axis between adjacent drive units such that it at least partially surrounds and is in contact with the threaded spindle, sufficient lubrication of the thread engagement between the threaded spindle and the drive units in at least partial contact with it is achieved even under cryogenic conditions. In particular, the solid lubricant element has a contact layer with an inner surface that is in contact with the external thread of the threaded spindle or with a radially outer surface area of ​​the spindle's outer surface. The inner contact surface can be shaped such that it is curved in the circumferential direction defined by the spindle axis and completely or partially surrounds the threaded spindle in the circumferential direction.The contact between the inner surface of the solid lubricant element and the outer surface of the spindle exists at least circumferentially or via a section extending circumferentially. Additionally, contact exists between the... The solid lubricant element's inner surface and the spindle's outer surface are lubricated at least over a section of the solid lubricant element's longitudinal extent along the spindle axis and at least over a section of the spindle's outer surface extending along the spindle axis between two spaced-apart drive units. This occurs when the threaded spindle, through its rotational movement, picks up solid lubricant from the solid lubricant element, which at least partially surrounds it and makes contact within the surrounding area, and transfers it into the thread engagement area between the threaded spindle and the drive units. During transport, effective lubrication is achieved there, which is maintained even under cryogenic conditions.

[0011] According to one embodiment, the solid lubricant element has a hollow cylindrical geometry and is in contact with the external thread of the threaded spindle via a complementary internal thread. The inner surface of the solid lubricant element can be designed as the complementary internal thread.

[0012] According to a further embodiment, the material of the solid lubricant element, or at least the material of its contact layer, comprises carbon or boron nitride, or the material of the solid lubricant element, or at least the material of its contact layer, consists of carbon or boron nitride, or a combination of carbon and boron nitride. The expression "consist of" relating to a feature, e.g., in respect of an aspect of a material, an object, or a structural component, here means that the respective feature is the exclusive feature of the object or structural component in that same aspect. In contrast, the expression “educated from” or “exhibiting” does not have such an exclusive meaning here.

[0013] According to a further embodiment, each of the drive units of at least one pair of drive units adjacent to each other along the spindle axis has an elastically deformable frame body. The frame body has receiving spaces or actuator receiving spaces. At least one of the electromechanical actuators is located at least partially in each of the actuator receiving spaces. In particular, the actuator receiving spaces can each be formed by a closed structure or a closed component section of the frame body, wherein the actuator receiving spaces, viewed at least in the direction of the spindle axis, completely surround the electromechanical actuators inserted into the actuator receiving spaces.Alternatively or additionally, the frame body has a receiving section for receiving a section of the threaded spindle or the spindle's outer surface extending in the direction of the spindle axis, which is in particular formed as a closed structure or as a closed component section of the frame body, wherein, in the direction of the. Viewed from the spindle axis, the receiving section for the threaded spindle completely surrounds the spindle or the respective spindle chamber into which a section of the threaded spindle can be inserted. It can be particularly advantageous that a surface of a corresponding receiving chamber intended for contact with an electromechanical actuator is formed by a surface of a clamping device for clamping or securing the respective electromechanical actuator of a pair of adjacent drive units in the respective receiving chamber. It can be particularly advantageous that the clamping device is formed by a plurality of wedge-shaped elements or by a screw, each of which has a clamping device contact surface facing an actuator contact surface.The clamping device is configured such that, when actuated, its contact surface is pressed against the respective actuator contact surface with a defined force, thereby clamping or clamping the actuator in its designated mounting space in a predetermined manner. By using an arrangement of wedge-shaped elements in contact with each other, or by providing a screw that can be inserted into the frame at a corresponding location, tolerances in the geometry of the electromechanical actuators can be easily accommodated, and the electromechanical actuator can be clamped or clamped in the mounting space with a defined force.

[0014] According to a further embodiment of the spindle drive according to the invention, the frame body of each of the drive units has a drive area with two drive sections, which are integral sections of the frame body and, in particular, of the receiving section for receiving a section of the threaded spindle. The drive sections are located opposite each other with respect to the spindle axis, viewed in the direction of the spindle axis. Each of the drive sections of the frame body has a drive section contact surface, wherein the drive section contact surfaces of the drive sections are opposite each other with respect to the spindle axis and each contact one of two threaded spindle circumferential sections.This means that the frame body is configured in such a way that, when actuated accordingly, the actuators move the opposing drive sections in such a way that their drive section contact surfaces set the threaded spindle in rotation in a predetermined manner. In particular, it can be provided that the two receiving spaces for the electromechanical actuators are separated from each other by a separating web section of the frame body and are thereby connected or coupled to each other via the coupling web section, and that the coupling web section simultaneously couples the two drive sections to each other. Preferably, the separating web section extends radially with respect to the spindle axis and has one radial end connected to the coupling web section.In this context, it can be particularly advantageous that the two drive sections are additionally coupled to each other via a connecting web section of the frame body, wherein the connecting web section is arranged opposite the coupling web section with respect to the threaded spindle, and the coupling web section and the connecting web section and the two drive sections together form a closed receiving section for the threaded spindle.

[0015] According to another embodiment, the electromechanical actuators are designed as piezoelectric or electrostrictive or magnetostrictive actuators, whereby in the case of magnetostrictive actuators it can be particularly advantageous for the frame bodies to have a material with magnetostrictive properties.

[0016] According to a further embodiment, the electromechanical spindle drive has a device for acquiring and processing measurement or operating data relevant to the state of the electromechanical spindle drive, which is designed to continuously acquire and process the measurement or operating data during the running time of the electromechanical spindle drive and optionally link them together, so that a picture of the state of the electromechanical spindle drive can be derived from it.

[0017] The invention further relates to a method for operating an embodiment of the spindle drive described herein, and in particular an electromechanical spindle drive as described above, in which the two electromechanical actuators of a drive unit are supplied with sawtooth-shaped electrical signals, in particular voltages, that are opposite in time and preferably in phase. "Opposite in time" here means that in a time interval with a rising edge of one of the sawtooth signals, a falling edge is present in the other sawtooth signal, and vice versa. In particular, with regard to the temporal evolution of two counter-rotating and in-phase sawtooth-shaped electrical signals, these are arranged as mirror images of each other with respect to the corresponding time axis. "In phase" here means that the periods of the two electrical signals are identical relative to each other and their zero crossings or zero values ​​occur at the same or substantially the same times.

[0018] The invention further relates to a positioning device with an electromechanical spindle drive as described above.

[0019] The term “essentially” in relation to a feature or value is understood herein to mean in particular that the feature contains a deviation of up to 20% and specifically up to 10% from the feature or its geometric property or value.

[0020] The term "one-piece" in relation to a part or component means that the part or component is manufactured as a single piece. The part or component may be made up of several pieces or parts that are connected, coupled, or joined together. In this context, the term "manufactured from a single piece" means that the part or component is manufactured from a single, original workpiece.

[0021] The term "electromechanical" here refers to the property of an element or the material of that element, whereby it undergoes a mechanical deformation, such as a change in length, when subjected to an electrical voltage or current. In particular, an electromechanical material is understood to be a piezoelectric, electrostrictive, or magnetostrictive material.

[0022] Unless otherwise stated, the logical conjunction “or” in relation to two alternatives A and B is to be understood as a non-exclusive disjunction, i.e. A or B or both.

[0023] If the terms “at least” or “at least” are used herein in reference to the number of a feature or element or part of the electromechanical spindle drive (hereinafter referred to as the initial feature), If the following are used (as defined below), then – unless explicitly stated otherwise – the further characteristics relating directly or indirectly to them (hereinafter referred to as reference characteristics) are to be understood as follows: if the minimum number of the respective output characteristic is present, the reference characteristics apply to this minimum number, and if the number of the output characteristic exceeding the minimum number is present, the reference characteristics apply either only to the minimum number of the output characteristic, or only to a part of the number of the output characteristic exceeding the minimum number, or to the entire number of the output characteristic exceeding the minimum number, and thus to the entire number of the output characteristic.For example, if a minimum number of two is mentioned with regard to a characteristic A (initial characteristic), then the further characteristics (reference characteristics) relating directly or indirectly to characteristic A either apply exactly to the minimum number of two, or - in the case of the existence of a number exceeding the minimum number of two with regard to characteristic A, for example four - the reference characteristics apply either only to the minimum number of two, or to a part or to the entirety of the number of characteristics A exceeding the minimum number of two.

[0024] The features described above and other features of the embodiments according to the invention are explained in the description of the figures and the claims. The individual features can be implemented either separately or in combination as embodiments of the invention. Furthermore, they can describe advantageous embodiments that are independently patentable and whose protection may be claimed only during or after the filing of the application.

[0025] Brief description of the characters

[0026] The foregoing, as well as further advantageous features of the invention, are illustrated in the following detailed description of exemplary embodiments of the invention with reference to the accompanying schematic drawings. It shows / show

[0027] Figures 1a), b): different views of an electromechanical spindle drive according to the invention with magnetostrictive actuators

[0028] Figures 2a, b): different views of an electromechanical spindle drive according to the invention with piezoelectric actuators

[0029] Figures 3a, b): different views of an electromechanical spindle drive according to the invention with piezoelectric actuators which are clamped in the receiving space by means of wedge-shaped elements.

[0030] Figure 4: Positioning device in the form of an XY table with electromechanical spindle drives according to the invention

[0031] Detailed description of embodiments according to the invention

[0032] In the exemplary embodiments or variants described below, functionally or structurally similar elements are, as far as possible, provided with the same or similar reference numerals. Therefore, to understand the features of the individual elements of a particular exemplary embodiment, reference should be made to the description of other exemplary embodiments or to the general description of the invention.

[0033] Figure 1 shows in illustrations a) and b) a first possible embodiment of a spindle drive 1 according to the invention. This comprises a threaded spindle 2 with an external thread and a spindle axis SA extending along the longitudinal dimension of the threaded spindle 2. Two preferably identical drive units 3 are arranged spaced apart from each other along the spindle axis SA and are mechanically connected to each other by a connecting device 7 in the form of a rigid connecting element. A solid lubricant element 8 in the form of a hollow cylinder is arranged between the two spaced-apart drive units 3. This element has an internal thread complementary to the external thread of the threaded spindle 2 and is thus in thread engagement with the threaded spindle 2. The solid lubricant element 8 is held by the two drive units 3 or clamped between them by means of the connecting element.It is conceivable to use an elastically deformable connecting element, such as a spring element, for the connecting device 7.

[0034] Each of the drive units 3 includes an elastically deformable Frame body 4, which has two receiving spaces 40, into each of which an electromechanical actuator 6 is inserted or clamped. Each of the two receiving spaces 40 has a closed structure or is formed by a closed component section of the frame body 4, such that each electromechanical actuator 6 received in one of the receiving spaces 40 is completely surrounded or enclosed by the corresponding receiving space 40 or a respective component section of the frame body 4. The receiving spaces 40 are preferably identical and arranged symmetrically with respect to a separating web section 47, which separates the two receiving spaces 40 and is formed integrally with the frame body 4, and which runs essentially along the center of the frame body 4 and extends in a radial direction. It is conceivable that one or both of the receiving spaces 40, orthe respective component section has or has a structure that deviates from a closed structure, in particular a structure that is not closed and thus does not completely surround the electromechanical actuator used therein, whereby an identical structure or a symmetrical arrangement of the corresponding receiving spaces is also advantageous here.

[0035] The frame body 4 also has a receiving section 42 with a spindle chamber for receiving a section of the threaded spindle 2. The spindle chamber has a spindle chamber axis that coincides with the spindle axis of the threaded spindle 2 when the section of the threaded spindle 2 is inserted into the spindle chamber. The receiving section 42 of the frame body 4 can have a closed structure and completely surrounds or encloses the section of the threaded spindle 2 received therein.The closed structure of the receiving section 42 of the frame body 4 results from the joint arrangement of the two drive sections 44, which are arranged laterally to the threaded spindle 2 and engage with it in thread engagement, the coupling web section 45, which connects the two drive sections 44 in the area of ​​the receiving spaces 40 and thus at the proximal position, and the connecting web section 46, which connects the two drive sections 44 at the distal position. The coupling web section 45 and the connecting web section 46 can be essentially the same length.

[0036] All previously listed sections of the frame body 4 are formed integrally with it, although it is conceivable to form individual or all sections from separate parts. In particular, the frame body 4 can be formed integrally.

[0037] The two electromechanical actuators 6 inserted into the frame body 4 or into its receiving chambers 40 are magnetostrictive actuators, each comprising a magnetostrictive and column-shaped element 66, an electrical coil 64 surrounding or enclosing the magnetostrictive element e, and two permanent magnets 62 adjacent to the respective end sections of the magnetostrictive element 66. The two permanent magnets 62, arranged at the ends of the magnetostrictive element 66, each bear against a wall surface of the receiving chamber 40 with one of their surfaces.

[0038] Electrical activation or actuation of the respective electromechanical actuator via an electric current or an electric voltage results in a change in length of the column-shaped magnetostrictive element, which in turn causes a movement of the associated drive section 44. The transmission of the movement or deformation of the electromechanical actuator 6 to the associated and adjoining drive section 44 is made possible by the elastic deformability of the frame body 4 and its specific design and structure. Specifically, a change in length of one of the electromechanical actuators 6 results in an essentially analogous linear or translational drive movement of the drive section 44 adjoining the corresponding electromechanical actuator 6 with respect to its longitudinal extent. Due to the thread engagement of the section of the drive section 4 in contact with the threaded spindle 2, the linear or translational movement of the drive section 44 leads to a driving movement of the threaded spindle 2, which, due to the structural and mechanical boundary conditions, is converted into a rotational movement of the threaded spindle 2.

[0039] It is preferred that the other electromechanical actuator 6 is electrically controlled by an opposing voltage signal such that it identical but opposite movement or deformation is performed, resulting in an opposite linear or translational drive movement of the other drive section 44, which supports the rotary drive of the threaded spindle 2 caused by the first drive section 44. It is particularly advantageous if the opposing voltage signals applied to the two electromechanical actuators 6 of a drive unit 3 have the same phase or are in phase. The use of sawtooth-shaped or sawtooth-like voltage signals is especially advantageous here, as the time interval of the flatter flank results in a correspondingly slower deformation of the electromechanical actuator 6 and thus a slow drive movement of the drive sections 44, which, due to static friction between the drive sections 44 and the threaded spindle 2, leads to a following or...a driving movement of the threaded spindle 2. In the time range of the steeper flank of the sawtooth-shaped voltage signals, however, a movement of the drive sections 44 occurs in the opposite direction to the drive movement and is significantly faster, which leads to the onset of sliding friction between the drive sections 44 and the threaded spindle 2, so that no driving or only a negligible driving movement of the threaded spindle 2 results.

[0040] The drive sections 44 can follow the movement or deformation of the electromechanical actuators 6, in particular because the frame body 4 possesses elastic deformation capability primarily due to its structural design. To this end, the frame body 4 has several thin, web-like sections that function, at least in some areas, like a type of rigid joint. In addition to the coupling web section 45, the connecting web section 46, and the separating web section 47 – which have already been described – a side web section 48 for each receiving space 40, which is arranged opposite the separating web section 47 with respect to the intervening electromechanical element 6, also contributes to the elastic deformation capability of the frame body 4.Due to the symmetrical structure of the frame body with respect to a central axis that passes through the center of the separating web section 47 and through the threaded spindle axis, it follows that the two side web sections 48 have essentially the same length.

[0041] The aforementioned sections, which function at least partially as solid-body joints, also enable a guided and thus defined movement of the drive sections, whereby the corresponding linear or translational drive movement direction is tangential to the threaded spindle and parallel to each other, and the drive sections remain in defined contact or thread engagement with the threaded spindle.

[0042] Due to the use of two drive units 3 spaced apart from each other, an additional and in particular passive bearing of the threaded spindle 2 is unnecessary, since its bearing is achieved solely through its arrangement in the two receiving sections 42 and the mechanically fixed connection of the two drive units 3 via the connecting device 7.

[0043] Fig. 2 shows in illustrations a) and b) another possible embodiment of a spindle drive 1 according to the invention. The essential difference to the embodiment shown in Fig. 1 is that electromechanical actuators 6 in the form of piezoelectric elements are used here. In addition, the two receiving chambers 40 and the receiving section 42 have a different geometric shape. It is noticeable that both the coupling web section 45 and the essentially equally long connecting web section 46 are significantly longer than in the embodiment according to Fig. 1. At the same time, the side web sections 48 are significantly shorter in this embodiment than in the embodiment shown in Fig. 1.

[0044] Another difference from the embodiment shown in Fig. 1 lies in the design of the connecting device 7, which here is designed in such a way that it covers the solid lubricant element laterally.

[0045] Each of the frame bodies 4 or each of the two drive units 3 of the electromagnetic spindle drive 1 shown in Fig. 2a) has an associated threaded bore 49 for each receiving space 40, which extends through to the corresponding receiving space 40 and into which a clamping device 9 in the form of a screw can be screwed, so that the electromechanical actuator 6 in the form of a piezoelectric element inserted in the respective receiving space 40 can be contacted and clamped or pre-tensioned via its end surface.

[0046] Fig. 3 shows in illustrations a) and b) another possible embodiment of an electromechanical spindle drive 1 according to the invention, which differs essentially from the embodiment shown in Fig. 2 in that the clamping device 9, with which the piezoelectric actuator inserted in the respective receiving space 40 can be clamped or pre-tensioned, consists of an arrangement of three wedge-shaped elements 92, wherein adjacent wedge-shaped elements 92 are arranged opposite to each other.

[0047] According to the invention, a positioning device 100 with at least one spindle drive 1 is also provided, wherein each of the at least one spindle drive 1 is implemented according to an embodiment of the spindle drive 1 according to the invention. The positioning device 100 has a positioning element 104 as a driven element or component, wherein the positioning element 104 can be set in motion relative to the spindle drive 1 in at least one direction by actuating the threaded spindle 2. For this purpose, the respective threaded spindle 2 is coupled to the positioning element 104. By way of example, Fig. 4 shows a positioning device 100 in the form of an XY table, in which the positioning element 104 is movable along two orthogonal directions or axes, wherein the respective axis is driven by an electromechanical spindle drive 1 according to the invention.The translational displacement and guidance of the positioning element 104 relative to a stationary base plate 106 along the axes of movement is achieved by means of band-shaped solid joints 102, in particular made of nitinol, which together hold the positioning element 104 located in the center of the positioning device 100. For this purpose, the respective end sections of the solid joints 102 facing the positioning element 104 are connected to it, and the opposing end sections of these solid joints 102 are connected to a crossbeam-shaped movement element 110. Each of the movement elements 110 is connected to two of the four base elements 108 mechanically fixed at the four corners of the base plate 106 by means of two aligned solid joints 102.coupled, so that a total of four solid body joints 102 are arranged on each movement element 110.

[0048] Only two of the motion elements 110 are actively driven linearly by a respective electromechanical spindle drive according to the invention, while the two remaining motion elements 110 passively follow the movement of the two driven motion elements 110 caused by the spindle drives. It is conceivable that all four motion elements 110 are actively driven by an electromechanical spindle drive according to the invention.

[0049] The positioning element 104 can, as shown in Fig. 4, essentially have a square frame shape, and on all four sides of this frame or the positioning element 104 the corresponding ends of the two associated solid body joints 102 are arranged at the two respective and opposite end sections or edge sections, wherein these two solid body joints 102 are arranged parallel to each other.

[0050] The two solid body joints 102, which are arranged in alignment at the two opposite end sections of each of the movement elements and which connect the respective movement element 110 with the two corresponding base elements 108, are arranged essentially perpendicular to the solid body joints, which are also arranged at the two opposite end sections and which connect this movement element 110 with the positioning element 104.

[0051] The foregoing description of exemplary embodiments is to be understood as illustrative. The disclosure thereby enables the person skilled in the art, on the one hand, to understand the present invention and its associated advantages, and, on the other hand, also includes, in the understanding of the person skilled in the art, obvious modifications and alterations of the described structures and methods. Therefore, all such modifications and alterations, insofar as they fall within the scope of the invention as defined in the appended claims, as well as equivalents, are to be covered by the protection of the claims.

[0052] Reference symbol list: 1 Electromagnetic spindle drive 2 threaded spindles 3 Drive unit 4 frame bodies 6 electromechanical actuator Connecting device, solid lubricant element, clamping device Receiving space (of frame body 4) Receiving section (of frame body 4) Drive section (of frame body 4) Coupling web section (of frame body 4) Connecting web section (of frame body 4) Separating web section (of frame body 4) Side web section (of frame body 4) Threaded bore Permanent magnet coil magnetostrictive element Surface (of the clamping device 9) wedge-shaped element (of the clamping device 9) positioning device Solid body joint positioning element base plate Basic element Movement element

Claims

Claims 1. Electromechanical spindle drive (1) comprising: a threaded spindle (2) with an external thread and a spindle axis (SA); two drive units (3) spaced apart from each other with respect to the spindle axis (SA), each of the drive units (3) having an elastically deformable frame body (4) comprising two receiving spaces (40) in each of which an electromechanical actuator (6) is inserted;and a connecting device (7) for mechanically connecting the drive units (3), wherein each of the frame bodies (4) has a receiving section (42) for the threaded spindle (2), which has two drive sections (44) integrally formed with the frame body (4), which contact opposite circumferential sections of the external thread of the threaded spindle (2) and which are moved by applying suitable electrical signals to the electromechanical actuators (6) via a deformation of the frame body (4) thereby caused, characterized in that a solid lubricant element (8) is arranged between the drive units (3) such that it at least partially surrounds the threaded spindle (2) and is in contact with it.

2. Electromechanical spindle drive (1) according to claim 1, characterized in that the solid lubricant element (8) has a hollow cylindrical geometry and is in contact with the external thread of the threaded spindle (2) via an internal thread shaped complementarily thereto.

3. Electromechanical spindle drive (1) according to claim 1 or 2, characterized in that the solid lubricant element (8) comprises carbon or boron nitride.

4. Electromechanical spindle drive (1) according to one of the preceding claims, characterized in that the receiving spaces (40) or the receiving sections (42) of the frame body (4) each form a closed structure and completely surround the electromechanical actuators (6) inserted therein or the threaded spindle (2) received therein.

5. Electromechanical spindle drive (1) according to claim 4, characterized in that a surface of a receiving space (40) provided for contact with the electromechanical actuator (6) is formed by a surface (90) of a clamping device (9).

6. Electromechanical spindle drive (1) according to claim 5, characterized in that the clamping device (9) is formed by a plurality of wedge-shaped elements (92) or by a screw.

7. Electromechanical spindle drive (1) according to one of the preceding claims 4 to 6, characterized in that the two receiving spaces (40) for the electromechanical actuators (6) are coupled to each other via a coupling web section (45) of the frame body (4), and the coupling web section (45) simultaneously couples the two drive sections (44) to each other.

8. Electromechanical spindle drive (1) according to claim 7, characterized in that the two drive sections (44) are additionally coupled to each other via a connecting web section (46) of the frame body (4), wherein the connecting web section (46) is arranged opposite the coupling web section (45) with respect to the threaded spindle (2), and the coupling web section (45) and the connecting web section (46) and the two drive sections (44) together form the closed receiving section (42) for the threaded spindle (2).

9. Electromechanical spindle drive (1) according to one of the preceding claims, characterized in that the electromechanical actuators (6) are designed as piezoelectric or electrostrictive or magnetostrictive actuators.

10. Electromechanical spindle drive according to claim 9, characterized in that the electromechanical actuators (6) are designed as magnetostrictive actuators and the frame bodies (4) have a material with magnetostrictive properties.

11. Electromechanical spindle drive according to one of the preceding claims, characterized in that it has more than two drive units (3), wherein two drive units (3) adjacent with respect to the spindle axis (SA) form a drive unit pair, and one of the drive unit pairs or a part of the drive unit pairs has a solid lubricant element (8) or all drive unit pairs have a solid lubricant element (8).

12. Electromechanical spindle drive according to claim 11, characterized in that one of the drive unit pairs or a part of the drive unit pairs has a connecting device (7) or all drive unit pairs have a connecting device (7).

13. Electromechanical spindle drive according to one of the preceding claims, wherein it comprises a device for acquiring and processing measurement or operating data relevant to the state of the electromechanical spindle drive, which is configured to acquire and process the measurement or operating data during the running time of the electromechanical spindle drive and optionally to link them together, so that a picture of the state of the electromechanical spindle drive can be derived from it.

14. Electromechanical spindle drive according to one of the preceding claims, characterized in that the electromechanical spindle drive has more than two drive units (3), of which two drive units (3) arranged adjacent to each other form a drive unit pair, wherein at least one of the drive unit pairs has a solid lubricant element (8) arranged between its two drive units (3) and at least one of the drive unit pairs has a connecting device (7) connecting its two drive units (3) to each other.

15. Method for operating an electromechanical spindle drive (1) comprising a threaded spindle (2), at least two drive units (3) engaged with the threaded spindle (2) and mechanically connected to each other via a connecting device (7) and spaced apart from each other, each comprising at least two electromechanical actuators (6), and a solid lubricant element (8) arranged between the drive units (3), characterized in that the two electromechanical actuators (6) of at least one of the drive units (3) are supplied with opposing and sawtooth-shaped electrical signals.

16. Positioning device (100) with an electromechanical spindle drive (1) comprising: a threaded spindle (2) with an external thread and a spindle axis (SA); at least two drive units (3) spaced apart from each other with respect to the spindle axis (SA), each of the drive units (3) comprising an elastically deformable frame body (4) comprising two receiving spaces (40) into each of which an electromechanical actuator (6) is inserted;and a connecting device (7) for mechanically connecting the drive units (3), wherein each of the frame bodies (4) has a receiving section (42) for the threaded spindle (2), which has two drive sections (44) integrally formed with the frame body (4), which contact opposite circumferential sections of the external thread of the threaded spindle (2) and which are moved by applying suitable electrical signals to the electromechanical actuators (6) via a deformation of the frame body (4) thereby caused, wherein a solid lubricant element (8) is arranged between the drive units (3) such that it at least partially surrounds the threaded spindle (2) and is in contact with it.

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