Drive device for an air spring valve and a valve with such a

Abstract

Drive device (100) for a valve, in particular for an air spring valve (300), comprising: a stepper motor (110) comprising a stator arrangement (120) and a rotor arrangement (140) arranged radially within the stator arrangement (120), a motor shaft (150) which is arranged to rotate about a longitudinal axis (L) together with the rotor arrangement (140) within the stator arrangement (120), and a coupling element (200) for transmitting a rotational movement of the motor shaft (150) into a translational stroke movement, wherein the coupling element (200) is arranged substantially in an interior space (122) of the stator arrangement (120), and wherein the coupling element (200) is designed in a sleeve-like manner and at least partially surrounds the motor shaft (150).

Description

Technical field The invention relates to a drive device for an air spring valve, comprising a stepper motor comprising a stator and a rotor arrangement arranged radially within the stator, and a valve with such a rotor arrangement. The present invention is described below primarily in connection with an air spring valve. Although the advantages achievable through the invention are particularly pronounced with an air spring valve, the invention can also be advantageously used with other valves whose operating principles may differ significantly from those of an air spring valve. State of the art Document WO 2019 / 190 013 A1 discloses a solenoid valve arrangement for switching modes in a suspension system. This arrangement establishes an internal path, independent of any external path, for switching the fluid mode, thereby achieving equilibrium between the pressure acting on the inner and outer surfaces of the diaphragm. The opening and closing of the orifice is smoothly controlled by adjusting a relatively small amount of operating power applied to a solenoid coil, preventing the sticking of a moving rod relative to a magnetic core during solenoid operation. The valve thus performs the mode switching and minimizes the cross-sectional area of ​​the air in the internal path for the fluid flow, providing a narrow cross-sectional section.This implements an air cushion function, which reduces the impact noise of the valve caused by the opening / closing process. DE 10 2020 104 778 A1, which represents published prior art according to §3(2) PatG, describes a conventional drive device. In particular, it specifies a linear actuator comprising an electric motor with a rotor and a stator. The rotor is designed to drive a shaft. A coupling element for transmitting the rotational movement of the shaft into a translational linear motion is non-rotatably connected to the shaft via a shaft. For this purpose, the coupling element includes an external thread that engages with an internal thread of an actuator, and when the shaft, and thus the coupling element, rotates, this causes a translational linear motion of the actuator. The coupling element is arranged axially outside and, in particular, below the electric motor. EP 3 696 453 A1 relates to another known drive device for a valve, comprising an electric motor with a stator and a rotor. The rotor includes a rotor shaft with a guide section that incorporates an internal thread. A shaft extends axially from the rotor and forms a valve element at its lower end. A guide body, which is fixed in a housing part of the valve, includes an external thread section that engages with the internal thread section of the rotor shaft by means of a feed thread. This converts a rotational movement of the rotor shaft into a rotational and translational stroke movement of the rotor. The shaft moves integrally with the rotor and is axially displaceable within the guide body. CN 1 10 100 088 A relates to a valve arrangement for the translational movement of a valve element integrally mounted on a valve stem by converting a rotational movement into a purely translational movement by means of a transmission device. The transmission device comprises an input gear driven by a drive motor arranged axially offset and above the input gear, a cylindrical cam, and two or more bearing units. The cylindrical cam is rotationally fixed but axially displaceable with the input gear. The valve stem is integrally movable up and down along the axis of rotation of the cylindrical cam, but rotatable independently of the cam. The bearing units are each fixed at one axial end in a housing and engage with their opposite axial end in a corresponding cam recess. This causes the cam to move both rotationally and translationally as the input gear rotates. The translational movement of the cam is integrally transmitted to the valve stem. Other known drive devices are specified in DE 41 05 322 A1 , JP H08- 49 783 A EP 0 645 569 A2. The solenoid valve arrangements known from the prior art usually have a relatively long axial length. This regularly results in a large space requirement, which must be minimized, for example, in the field of vehicle applications. Description of the invention The object of the invention is to provide a drive device for an air spring valve belonging to the aforementioned technical field, which at least partially overcomes the problems known from the prior art. In particular, the object of the present invention is to propose a drive device for an air spring valve which has a compact and space-saving design. The invention is specified in the accompanying patent claims. The solution to the problem is defined in particular by the features of claim 1. According to the invention, the drive device for a valve, in particular for an air spring valve, comprises a stepper motor comprising a stator arrangement and a rotor arrangement arranged radially within the stator arrangement, and a motor shaft which is arranged within the stator arrangement to rotate about a longitudinal axis together with the rotor arrangement. The drive device additionally comprises a coupling element for transmitting a rotational movement of the motor shaft into a translational stroke movement. This achieves the technical advantage, for example, that the rotation of the rotor is directly transferred to the motor shaft, which is also located within the stator assembly. The torque transmission is therefore very precise and space-saving. A stepper motor within the meaning of this invention is understood to be a synchronous motor in which a rotor arrangement can be rotated by a small angle or a multiple thereof by a controlled, stepwise rotating electromagnetic field of stator coils of a stator arrangement. A coupling element within the meaning of this invention is understood to be a passive mechanical component suitable for converting a rotation into a translation. The coupling element itself does not perform a rotational movement but exclusively a translational up-and-down movement. Air spring valves are valves used to control an air suspension system or an air spring. Specifically, the valve is used to change the chamber volume of the air spring. The air spring valves make adjustable air spring systems possible, which, for example, allow for level adjustment and / or level control, whereby the ground clearance of a vehicle is adjusted and / or regulated. The air spring system can also be operated using gases other than air. In this context, the term "air spring" simply indicates that air is typically used as the gas, but is not limited to this. Using gases as the fluid results in fundamentally different requirements for air spring valves compared to using liquids. According to the invention, the coupling element is essentially arranged within an interior space of the stator assembly. This achieves, for example, the technical advantage of reducing the axial length of the drive device. Unused space between the rotor assembly and the motor shaft can be used to accommodate the coupling element, thereby increasing the compactness of the drive device. To increase the compactness of the drive device, the coupling element is designed in a sleeve-like manner according to the invention and surrounds the motor shaft at least partially. The sleeve-like design allows for almost complete utilization of the interior space within the stator assembly. Additionally, the sleeve-like design offers the advantage of being very simple to manufacture and therefore inexpensive components. Overall, this enables cost-effective production and easy assembly of the drive unit. In a preferred embodiment, the motor shaft has at least one guide element. This offers the technical advantage, for example, of enabling a simple mechanical connection between the motor shaft and the coupling element while maintaining high functionality. This provides the additional benefit of achieving high functional reliability with simple and inexpensive components. This advantage is particularly crucial in high-volume production environments. According to a particularly preferred embodiment, the coupling element comprises a cam for engaging the guide element. This achieves, for example, the technical advantage that the guide element can be moved along the cam by rotating the motor shaft. To achieve a particularly reliable compact design, the motor shaft is assigned a guide element for guidance within the cam, whereby the stroke of the coupling element depends on the rotation angle of the motor shaft and the pitch of the cam of the coupling element. This achieves, for example, the additional advantage that the drive device can be adapted to the desired application using two different parameters. In a further embodiment, the motor shaft includes an additional guide element for guiding it within the cam. This achieves, for example, the technical advantage of improved reliability of the drive device. The rotation of the motor shaft is transmitted to the coupling element via two guide elements, thus preventing the possibility of the coupling element tilting or jamming. According to an additional embodiment, the guide element and the further guide element are arranged opposite each other. This achieves, for example, the technical advantage that the transmission of rotation via the guide elements to a translation of the coupling element is particularly symmetrical. This further increases functional reliability. For example, both guide elements can run within the same track of the coupling element, which simplifies the manufacture of the coupling element and the assembly of the drive device. Alternatively, however, each guide element can slide within its own assigned track. In an additional embodiment, the interior of the stator assembly is bounded by an upper bearing element and a lower bearing element. This offers the technical advantage, for example, that all components within the stator assembly can be supported. A further advantage arises from the fact that the upper and lower bearing elements can be used to mount the stator assembly. To keep the stepper motor assembly free of axial forces, the motor shaft is supported between the upper and lower bearing elements. This achieves the technical advantage, for example, of reducing wear on the stepper motor. Generally, it is beneficial for the service life of a stepper motor if the load is reduced solely to torque. Axial forces are thus transmitted exclusively to the upper and lower bearing elements. According to a particularly advantageous embodiment, the lower bearing element has a contour for the engagement of the coupling element. According to a further embodiment, the engagement of the coupling element with the contour forms an anti-rotation device. This achieves, for example, the technical advantage that the stroke behavior of the coupling element, and thus the actuation of the valve body, is particularly reliable. To ensure particularly smooth and low-wear operation of the drive unit, a ball bearing is used to absorb axial forces at the upper bearing element. This achieves the technical advantage, for example, that axial forces occurring during operation of the drive unit do not lead to wear at the bearing points. In an additional embodiment, the ball bearing has at least one ball located on the longitudinal axis. This offers the additional advantage of making the axial force bearing inexpensive to manufacture and efficient to assemble. Alternatively, a conical bearing arrangement could be used instead of a ball. This would also allow for a significantly reduced friction surface, preventing axial forces occurring during operation of the drive device from causing wear at the bearing points. With a conical bearing arrangement, assembly of the drive device would be particularly simple due to the reduced number of components. According to another embodiment, the coupling element is connected to an actuating element for moving a valve body between an open and a closed position. This achieves, for example, the technical advantage that the stroke movement of the coupling element can be transferred to the valve body. The actuating element can thus serve as an adapter between the drive device and different valve bodies, making one drive device applicable to different valves. According to a particularly preferred embodiment, the problem is solved by the features of claim 14. According to the invention, the solution relates to a valve, in particular an air spring valve, with a drive device according to one of the preceding embodiments. This achieves similar technical advantages to the preceding embodiments. For example, the rotation of the rotor is transmitted directly to the motor shaft, which is also located within the stator assembly. The torque transmission is therefore very precise and space-saving. Furthermore, a drive device for a valve, in particular for an air spring valve, is described. The drive device comprises a stator assembly with a first winding unit having a first electrical connection and a second winding unit having a second electrical connection. Additionally, the first winding unit and the second winding unit are stacked along a common central longitudinal axis and configured to rotate a rotor assembly, which can be positioned within an interior space of the stator assembly, about the central longitudinal axis. The first electrical connection and the second electrical connection are located at the end faces of the first winding unit. The front-facing arrangement of the electrical connections on the first winding unit allows for a compact and space-saving design of the drive unit and thus of the air spring valve. The housing of the air spring valve can be cylindrical in the circumferential direction, which significantly simplifies the insertion of the air spring valve in confined spaces, for example in the automotive sector. A stator assembly is a stationary component of a stepper motor used to generate an electromagnetic field with the aid of winding units or so-called stator coils. Within the interior of the stator assembly, a rotor assembly is rotated by a small angle or a multiple thereof by a controlled, stepwise rotating electromagnetic field from the stator coils. The first winding unit can comprise a first iron circuit with a first iron circuit top, a first iron circuit bottom, and a radially outer tube wall. This offers the technical advantage, for example, that the first iron circuit is easy to assemble due to its modularity. For instance, the first iron circuit top, the first iron circuit bottom, and the tube wall are each made from sheet metal bending parts. This eliminates the need for deep-drawn parts. Overall, this results in a cost-effective and simple manufacturing process for the stator assembly and thus the drive device. The second winding unit can comprise a second iron circuit with a second iron circuit top, a second iron circuit bottom, and a radially external tube wall. The technical advantages are comparable to those of the preceding embodiment. Thus, the second iron circuit is also easy to assemble due to its modularity. For example, the second iron circuit top, the second iron circuit bottom, and the tube wall can each be manufactured from sheet metal bending parts. For instance, the use of deep-drawn parts can be avoided. Overall, this results in a cost-effective and simple manufacturing process for the stator assembly and thus the entire drive device. To further simplify the assembly of the drive unit, the radially outer tube walls of the first and second winding units are designed as a single, continuous tube wall. This also offers the technical advantage of reducing the number of components required. For example, deep-drawn parts can be eliminated, further reducing manufacturing costs. The tube wall can be manufactured, for instance, as a stamped and then rolled component. The first lower iron circle section of the first winding unit and the second upper iron circle section of the second winding unit can be adjacent to each other and share a common radial groove for transferring a connecting cable from the second winding unit to the first. This offers the technical advantage that the connecting cable, also called winding wire, from the second winding unit can be transferred to the first winding unit via the radial groove. For example, the connecting cable of the second winding unit can start at the end connection of the first winding unit and first wrap around the first winding unit several times. The connecting cable is then transferred via the radial groove to the second winding unit to wind the second winding carrier.The connecting cable is routed back to the end-face connection on the first winding unit via the radial groove back onto the first winding carrier of the first winding unit. There, the connecting cable wraps around the first winding unit several times again and is then connected to the contact at the end-face connection. The first iron core section of the first winding unit can have at least two connection openings for the first and second connection cables. This offers the technical advantage, for example, of allowing the connection cables to be fed directly to the end-face connection. For example, the first iron core section of the first winding unit may have four connection openings for the connection cables. Preferably, the geometry of the connection openings is such that the flow of magnetic field lines in the first iron core is not disrupted. This can be achieved, for example, by making the connection openings larger in the radial direction. In other words, the connection openings are each ring-segment shaped, with the angular interval of the side contours that circumferentially define the connection openings being between 5° and 30°. To further simplify the manufacture of the drive device, the first winding unit and the second winding unit each have a winding carrier, with both winding carriers being manufactured as a common one-piece double winding carrier using injection molding. For example, the first lower iron circle part of the first iron circle and the second upper iron circle part of the second iron circle can be designed directly as inserts for injection molding the double winding carrier. This achieves the technical advantage of further simplifying assembly and reducing the number of components. The second iron core section of the second winding unit can have an alignment opening for aligning the double winding carrier. This offers the technical advantage of further simplifying the assembly of the stator assembly and thus the entire drive unit. The precise relationship between the second iron core section and the winding unit is therefore clearly defined, reducing the risk of incorrect assembly and increasing assembly precision. For example, the winding unit can have a corresponding projection that can be formed directly on the winding unit during injection molding. For example, the alignment opening on the second iron core section is radially elongated, creating one radial degree of freedom. This offers two further technical advantages. First, the angular alignment between the second iron core section and the second winding unit is precisely defined. Second, the radial clearance between the second iron core section and the second winding unit allows for final alignment to be performed later during assembly. For instance, the precise alignment of the rotor assembly within the stator assembly, a crucial element for function and quality, can be adjusted later during assembly. The interior space of the stator assembly can be limited in the direction of the longitudinal axis by an upper bearing element and a lower bearing element. To simplify the installation of the upper bearing element, the upper bearing element has at least a first arm and a second arm for fixing the upper bearing element to the first iron circle top of the first winding unit. This achieves, for example, the technical advantage of reducing the weight of the upper bearing element. Additionally, it is possible to access the rotor assembly inside the stator assembly bypassing the upper bearing element. The upper bearing element, in a state arranged on the first iron circle top part, can have at least one centering opening for inserting a centering device between the stator arrangement and the rotor arrangement. This achieves, for example, the technical advantage that by inserting a centering device between the rotor and stator assembly, precise alignment of the rotor assembly within the stator assembly is possible. The more precise the centering, the smaller the radial play between the rotor and stator assembly can be. Overall, this improves the performance of the stepper motor while maintaining the same installation space. Due to the centering opening on the bearing element, which allows for the insertion of a centering device between the stator and rotor assemblies, simplified assembly is possible. This involves first inserting the centering device through the opening to ensure precise alignment of the rotor assembly within the stator assembly, then fixing the upper bearing element to the upper iron circle, and finally removing the centering device. This improves assembly precision and enhances the performance of the stepper motor and, consequently, the entire drive system. To further improve assembly, the bearing element has an outer contour that exposes the centering opening, with the outer contour positioned between the arms of the upper bearing element. For example, the centering device is designed as a sleeve with three arms for insertion between the rotor and stator assemblies. When the sleeve is fitted, the arms are inserted individually into the centering opening between the rotor and stator assemblies, between the first and second arms, the second and third arms, and the third and first arms of the bearing element. Furthermore, a method for manufacturing a drive device according to one of the preceding embodiments is described. The method comprises the steps of providing the stator assembly, inserting the rotor assembly into the interior of the stator assembly, placing the upper bearing element onto the first iron circle top, applying a centering device between the rotor assembly and the stator assembly for the precise positioning of the rotor assembly in the stator assembly, fixing the upper bearing element onto the first iron circle top, and removing the centering device. The technical advantages are comparable to those mentioned above, namely that the front-side arrangement of the electrical connections on the first winding unit allows for a compact and space-saving design of the drive device and thus of the air spring valve. In addition, the technical advantage is achieved that by inserting a centering device between the rotor and stator assembly, precise alignment of the rotor assembly within the stator assembly is possible. The more precise the centering, the smaller the radial play between the rotor and stator assembly can be. Overall, this improves the performance of the stepper motor while maintaining the same installation space. The method for manufacturing the drive unit is particularly easy to implement because the centering device is first inserted to ensure precise alignment of the rotor assembly within the stator assembly, and only then is the upper bearing element fixed to the upper iron circle. The centering device is removed only after the aligned upper bearing element is fixed to the upper iron circle. This improves the precision of the assembly and the performance of the stepper motor, and thus of the entire drive unit. When installing the centering device, a spacer can be positioned between the rotor and stator assembly. This spacer is, for example, designed as an arm that can be inserted into the gap. The centering device may, for instance, comprise three arms, as this allows for precise alignment of the rotor within the stator assembly. For example, the three arms may be arranged at an angular distance of 120° from each other. To ensure the rotor assembly's alignment within the stator assembly remains correct, when fixing the upper bearing element to the first iron circle top, at least the first arm and the second arm are welded to the first iron circle top of the first winding unit. Alternatively, another joining method, such as gluing or mechanical locking, can be used to fix the upper bearing element to the first iron circle top. Furthermore, a drive device for a valve, in particular for an air spring valve, is specified, comprising at least one electrical connection for electrically connecting the drive device to a power source. The drive device includes a housing for receiving the drive device, wherein the electrical connection has at least one contact pin extending through a housing connection opening from an inner to an outer housing surface, and wherein the contact pin has a sealing unit for fluidically sealing the housing connection opening, which surrounds the contact pin on the inside of the housing. This achieves the technical advantage, for example, of ensuring a seal between the housing connection openings and fluids and operating media, both from the inside of the housing relative to the outside and vice versa. Because the sealing unit is located inside the housing, it is protected against external influences, thus increasing the service life of the drive device. For example, the power connection can also have two, three, or any number of contact pins. The sealing unit can include a sealant radially compressed against the contact pin. This achieves the technical advantage, for example, of ensuring an effective seal both radially within the sealant, i.e., between the sealant and the contact pin, and radially outside the sealant, i.e., between the sealant and the housing connection opening. An additional advantage lies in the fact that sealants such as O-rings are readily available as standard components and therefore inexpensive. For example, such sealants are made of an elastomer material. The sealing unit can have a support sleeve that surrounds the contact pin on the inside of the housing. This offers the technical advantage, for example, of axially supporting the O-ring and thus preventing it from slipping. Additionally, the O-ring is completely encapsulated, providing optimal protection against mechanical stress and wear. Overall, this increases the service life of the actuator and, consequently, the service life of the air spring valve. Based on this, the support sleeve is positioned directly next to the sealant and designed to transmit an axial force to the sealant. This also provides the additional technical advantage that the sealant can be precisely guided into its position during assembly using the support sleeve. To enable precise positioning of the sealing unit and thus increase the service life of the air spring valve, the housing connection opening has a first section with a first cross-section and a second section with a second cross-section, with a cross-sectional transition from the first to the second cross-section for positioning the sealing unit. This also offers the technical advantage of particularly reliable positioning of the sealing unit. In other words, this reduces the susceptibility to errors during assembly. The risk of leaks during operation of the air spring valve is reduced. The support sleeve can be designed for insertion into the first section of the housing connection opening. This achieves, for example, the technical advantage that, in addition to the O-ring, the support sleeve is also secured against slippage. The axial height of the sealing unit can be greater than the depth of the first section of the housing connection opening. This offers the technical advantage, for example, that the support sleeve protrudes from the first section of the housing connection opening and thus projects into the inside of the housing. This makes it possible, for instance, to exert axial pressure on the support sleeve and thus on the O-ring, thereby ensuring the stability of the sealing unit and eliminating the risk of it slipping. The drive unit can have a base body for mounting the contact pin, which also serves to support the support sleeve. This offers the technical advantage, for example, that the sealing unit cannot shift out of position after installation. The support sleeve is rigidly positioned between the O-ring and the base body and transmits an axial force to the O-ring. This improves the function of the sealing unit and increases its service life. For example, the base body can be designed as a circuit board for mounting the contact pins. Furthermore, a valve, in particular an air spring valve, is specified, with an actuating device according to one of the preceding embodiments. This achieves similar or comparable technical advantages to those in the preceding embodiments. In particular, a seal of the housing connection openings against fluids and operating media is ensured both from the inside of the housing to the outside and from the outside of the housing to the inside. The sealing unit is protected against external influences, and the service life of the air spring valve is increased. A method for manufacturing a drive device according to one of the preceding embodiments is also specified, comprising the steps of providing the drive device, arranging at least one contact pin on the base body, arranging the sealing unit, and arranging the drive device in the housing. This achieves similar or comparable technical advantages to those described above. In particular, the sealing of the housing connection openings against fluids and operating media is ensured both from the inside of the housing to the outside and from the outside to the inside. Because the sealing unit is located inside the housing, it is protected against external influences, thus increasing the service life of the drive device. For example, the power connection can also have two, three, or any number of contact pins. An additional technical advantage is the simplified assembly of the drive device. The sealing unit is simply plugged directly onto the contact pin, making assembly very easy. When arranging the sealing unit, the support sleeve can be placed on the contact pin. In a further step, the O-ring is applied to the contact pin coaxially with the support sleeve. This offers the technical advantage, for example, that the positioning of the O-ring can be carried out particularly easily and precisely. Due to the previously positioned support sleeve, the axial orientation of the O-ring is automatically and directly determined. When arranging the actuator in the housing, the contact pin can be guided through the housing connection opening, and the sealing unit can be inserted into the first section. This offers the technical advantage, for example, that the final positioning of the O-ring is necessarily very simple and precise. The support sleeve pushes the O-ring into the first section up to the cross-sectional transition from the first to the second cross-section. The positioning of the sealing unit is particularly reliable, thus reducing the potential for errors during assembly. The risk of leaks during operation of the air spring valve is reduced. The advantageous embodiments and combinations of features of the invention can be derived from the following detailed description and the entirety of the patent claims. Brief description of the drawings The drawings used to illustrate the embodiment show: Fig. 1 a sectional view of an air spring valve with drive device, Fig. 2 a sectional view of a stepper motor, Fig. 3 a coupling element, Fig. 4 a perspective view of a stepper motor with axially arranged electrical connections, Fig. 5 an exploded view of a first and a second iron circuit, Fig. 6 a top view of a stepper motor with upper bearing element, Fig. 7 another perspective view of a stator arrangement with axially arranged electrical connections, and Fig. 8 a sectional view of a current connection of a drive device. Basically, identical parts in the figures are marked with the same reference symbols. Ways to implement the invention Fig. 1 shows a sectional view of an air spring valve 300 with drive device 100. The air spring valve 300 comprises a housing 320, which seals the actuator 100 to the outside. Inside the housing 320 is the stepper motor 110 with a stator assembly 120 and a rotor assembly 140 located in the interior 122 of the stator assembly 120. The rotor assembly 140 comprises a motor shaft 150 and is arranged to rotate about a longitudinal axis L. The interior 122 of the stator assembly 120 is bounded on the upper side by an upper bearing element 124 and on the lower side by a lower bearing element 126. The upper bearing element 124 and the lower bearing element 126 serve to support the motor shaft 150 and, in particular, absorb axial forces that arise, for example, from the opening or closing of the valve body 310. Thus, the rotor assembly 140 is set into rotation by the stator assembly 120. The rotor assembly 140 is non-rotatably connected to the motor shaft 150 and is thus set in rotation via the rotor assembly 140. Additionally, the motor shaft 150 is surrounded by a sleeve-like coupling element 200. The coupling element 200 serves to transmit a rotation of the motor shaft 150 into a translational stroke movement for opening or closing the valve body 310. The rotation of the motor shaft 150 is transmitted to the coupling element 200 by means of two pin-shaped guide elements 152, 154. The pin-shaped guide elements 152, 154 are fixedly connected to the motor shaft 150 and extend laterally to the longitudinal axis L. For stability reasons, the guide elements 152, 154 are arranged opposite each other and engage in a cam 202 of the coupling element 200. The stroke or retraction of the coupling element 200 depends on the angle of rotation of the motor shaft 150 and the pitch of the cam 202 of the coupling element 200. Thus, the rotation of the motor shaft 150 can be transmitted to a stroke movement of the coupling element 200, with the resulting axial forces being absorbed by the upper bearing element 124 and the lower bearing element 126. As a result, the stepper motor 110 can be largely freed from axial forces. The lower bearing element 126 has an asymmetric contour 128 through which a lower section of the coupling element 200 extends during the lifting movement. Due to the engagement of the coupling element 200 with the contour 128, rotation of the coupling element 200 relative to the contour 128 is prevented. Thus, the contour 128, in conjunction with the coupling element 200, acts as an anti-rotation device. Below the coupling element 200 is an actuating element 220, which transmits the stroke movement of the coupling element 200 to the valve body 310. The valve body 310 has a laterally arranged sealing diaphragm 311, which compensates for the stroke movement of the valve body 310 and simultaneously seals the housing 320 to the outside. Additionally, the valve body 310 includes a sealing element 312, which seals the valve body 310 in the closed position by engaging the valve seat 314. The stator assembly 120 within the housing 320 comprises a first winding unit 121 and a second winding unit 123, which are stacked along a common central longitudinal axis L. Both the first winding unit 121 and the second winding unit 123 each have at least one electrical connection 125, 127 for operating the winding units 121, 123. The first electrical connection 125 is connected to the first winding unit 121, and the second electrical connection 127 is connected to the second winding unit 123. Both electrical connections 125, 127 are located on the upper end face of the first winding unit 121. The first winding unit 121 has its own first iron circle 129. The first iron circle 129 comprises a first iron circle top 130, a first iron circle bottom 131, and an outer pipe wall 135-1. The first iron circle top 130 is axially connected and welded to the outer pipe wall 135-1. The second winding unit 123 has its own second iron circle 132. The second iron circle 132 comprises a second iron circle top 133, a second iron circle bottom 134, and an outer pipe wall 135-2. The second iron circle bottom 134 is axially connected and welded to the outer pipe wall 135-2. The outer pipe wall 135-1 of the first iron circle 129 and the outer pipe wall 135-2 of the second iron circle 132 are designed as a single, continuous pipe wall 135. Both the first winding unit 121 and the second winding unit 123 each have a winding support 138-1, 138-2. The winding supports are arranged completely within the respective iron circle 129, 132. At the upper end of the housing 320 is a power connector 340 for electrically connecting the drive device 100 to a power source in order to operate the drive device 100 and thus the air spring valve 300. The power connector 340 comprises a total of three contact pins 342, which are arranged parallel to each other. The contact pins 342 extend through the housing wall. Each contact pin 342 extends from an inner housing surface 322 to an outer housing surface 324. Fig. 2 shows a sectional view of a stepper motor 110. A repeated description of features identical to those in the preceding figure is omitted. The upper bearing element 124 is fixed to the first iron ring upper part 130. The inner diameter of the interior space 122 in the stator assembly 120 is larger than the radial outer diameter of the upper bearing element 124. Consequently, a centering opening 250 is formed between the rotor assembly 140 and the stator assembly 120. The centering opening 250 is annular in plan view and is suitable for inserting a centering device between the stator assembly 120 and the rotor assembly 140. Fig. 3 shows a coupling element 200 in a preferred embodiment. The coupling element 200 surrounds the motor shaft 150 and is largely designed like a hollow cylinder. The coupling element 200 serves to transmit a rotation of the motor shaft 150 into a translational stroke movement for opening or closing the valve body 310. The rotation of the motor shaft 150 is transmitted to the coupling element 200 by means of two pin-shaped guide elements 152 and 154. These guide elements are fixedly connected to the motor shaft 150 and engage in a cam 202 of the coupling element 200. The stroke or retraction of the coupling element 200 depends on the rotation angle of the motor shaft 150 and the pitch of the cam 202 of the coupling element 200. Thus, the rotation of the motor shaft 150 can be transmitted to a stroke movement of the coupling element 200, with the resulting axial forces being absorbed by the upper bearing element 124 and the lower bearing element 126. Consequently, the stepper motor 110 can be largely freed from axial forces. The lower bearing element 126 has an asymmetric contour 128 in the form of two opposing kidney shapes. The coupling element 200 is longitudinally slotted laterally on a lower section, allowing the lower section of the coupling element 200 to engage with the asymmetric contour 128 during the lifting movement. Because the coupling element 200 engages with the contour 128, rotation of the coupling element 200 relative to the contour 128 is prevented, thus the contour 128, in conjunction with the coupling element 200, acts as an anti-rotation device. The upper bearing element 124 has a first arm 124-1, a second arm 124-2, and a third arm 124-3. The open end of each arm serves to be attached to and fixed against the first iron circle top 130 of the first winding unit 121. An outer contour 160 is located between each of the three arms 124-1, 124-2, and 124-3. The outer contour 160 provides a centering opening 250 (not shown) between the rotor assembly 140 and the stator assembly 120, which is suitable for inserting a centering device between the stator assembly 120 and the rotor assembly 140. The outer contour 160 is designed as an annular section. A centering device in the form of a sleeve with three arms can be used for insertion between rotor assembly 140 and stator assembly 120 to achieve optimal centering of the rotor assembly 140 within the stator assembly 120 with minimal play. Fig. 4 shows a perspective view of a stator assembly 120 with axially arranged electrical terminals 125-1, 125-2, 127-1, 127-2. The stator assembly 120 comprises the first winding unit 121 and the second winding unit 123 (not shown), which are stacked along a common central longitudinal axis L. Both the first winding unit 121 and the second winding unit 123 each have two electrical terminals 125-1, 125-2, 127-1, 127-2 for operating the winding units 121, 123. The first electrical terminals 125-1, 125-2 are connected to the first winding unit 121 and each pass through terminal openings 137-1 in the first iron ring top 130. Accordingly, the second electrical connections 127-1, 127-2 are connected to the second winding unit 123 and each is passed through connection openings 137-2 in the first iron circle upper part 130. The pipe wall 135 is continuously cylindrical in shape and extends both the first iron circle 129 of the first winding unit 121 and the second iron circle 132 of the second winding unit 123 radially outwards. Fig. 5 shows an exploded view of the first iron circle 129 and the second iron circle 132. The first iron circle 129 comprises the first iron circle upper part 130 and the first iron circle lower part 131. The first iron circle upper part 130 includes four end-face connection openings 137-1, 137-2. The connection openings 137-1, 137-2 serve to lead the electrical connections 125-1, 125-2 of the first winding unit 121 and the second winding unit 123 to the end-face outer side of the stator assembly 120. A radially outer side of the first iron circle 129 is covered by a first section of the tube wall 135. Radially inner, the first iron circle 129 has longitudinally extending iron circle fingers 170. Here, the iron circle fingers 170 are arranged circumferentially on both the upper iron circle part 130 and the lower iron circle part 131.In the assembled state of the stator assembly 120, the iron circle fingers 170 of the upper iron circle part 130 and the lower iron circle part 131 interlock alternately, thereby minimizing disturbances to the flow of the magnetic field lines in the iron circle 129. The advantage lies in the fact that the iron circle fingers 170 are integrally connected to both the upper iron circle part 130 and the lower iron circle part 131 and can therefore be manufactured as simple sheet metal bending parts. Accordingly, the second iron circle 132 comprises the second iron circle upper part 133 and the second iron circle lower part 134. The second iron circle lower part 134 includes the alignment opening 139 for aligning the associated double winding carrier 138 (not shown) during subsequent assembly. The radially outer side of the second iron circle 132 is covered by a second section of the tube wall 135. Both the first iron circle lower part 131 and the second iron circle upper part 133 each have a lateral radial groove 136-1, 136-2. The two radial grooves 136-1, 136-2 are aligned to allow the transfer of a connecting cable from the second winding unit 123 to the first winding unit 121 and vice versa. Fig. 6 shows a top view of a stepper motor 120 with an upper bearing element 124. The upper bearing element 124 has the first arm 124-1, the second arm 124-2, and the third arm 124-3. The open end of each arm is fixed to the first iron circle top 130 of the first winding unit 121. In this top view, the annular centering opening 250 is arranged radially outside the outer contour 160 between the rotor assembly 140 and the stator assembly 120. This opening is suitable for inserting a centering device between the stator assembly 120 and the rotor assembly 140 to achieve a minimal air gap. Two connection openings 137-1 are located between the first arm 124-1 and the third arm 124-3 of the upper bearing element 124. Through each of the two connection openings 137-1, a contact of the first electrical connection 125-1, 125-2 extends.Between the second arm 124-2 and the third arm 124-3 of the upper bearing element 124 are two further connection openings 137-2. A contact of the second electrical connection 127-1, 127-2 extends through each of the two connection openings 137-2. Fig. 7 shows another perspective view of a stator assembly 120 with axially arranged electrical connections 125, 127. The stator assembly 120 is shown without the tube wall 135 (not shown). A winding support 138-1 is assigned to the first winding unit 121. The winding support 138-2 is assigned to the second winding unit 123. Both winding supports 138-1, 138-2 are designed as a single, one-piece double winding support 138. The first lower iron circle part 131 and the second upper iron circle part 133 are arranged adjacent to each other and are joined together by injection molding during the manufacture of the double winding support 138. The first lower iron circle part 131 and the second upper iron circle part 133 each have a lateral radial groove 136-1, 136-2 for transferring one of the two connecting cables from the second winding unit 123 to the first winding unit 121 and from the first winding unit 121 to the second winding unit 123. A repeated description of identical features with the preceding figures is omitted. Fig. 8 shows a power connection 340 for a drive device 100. The power connection 340 serves to electrically connect the drive device 100 to a power source in order to operate the drive device 100 and thus the air spring valve 300. The drive device 100 is at least partially arranged in the housing 320, with a total of four contact pins 342 arranged parallel to each other. The contact pins 342 extend through the housing wall. Each contact pin 342 extends through a housing connection opening 326, which connects the inside of the housing 322 with the outside of the housing 324. On the inside of the housing 322, a sealing unit 330 is located at each contact pin 342, sealing the respective housing connection opening 326 against fluids and operating media. The sealing thus occurs both from the inside of the housing 322 to the outside of the housing 324 and from the outside of the housing 324 to the inside of the housing 322. Each sealing unit 330 comprises a sealing element 332 in the form of an O-ring and a support sleeve 334. The support sleeve 334 is inserted into the first section 327 of the housing connection opening 326 and is positioned between the base body 260 and the O-ring. The O-ring is thus positioned against the cross-sectional transition 329 between the first section 327 and the second section 328 and secured against slippage.The base body 260 is connected to the first terminal 125 and the second terminal 127, thus providing an electrical connection between the contact pins 342 of the power terminal 340 and the stepper motor 110 (not shown).

Claims

Drive device (100) for a valve, in particular for an air spring valve (300), comprising: a stepper motor (110) comprising a stator arrangement (120) and a rotor arrangement (140) arranged radially within the stator arrangement (120), a motor shaft (150) which is arranged to rotate about a longitudinal axis (L) together with the rotor arrangement (140) within the stator arrangement (120), and a coupling element (200) for transmitting a rotational movement of the motor shaft (150) into a translational stroke movement, wherein the coupling element (200) is arranged substantially in an interior space (122) of the stator arrangement (120), and wherein the coupling element (200) is designed in a sleeve-like manner and at least partially surrounds the motor shaft (150). Drive device (100) according to claim 1, characterized in that the motor shaft (150) has at least one guide element (152). Drive device (100) according to claim 2, characterized in that the coupling element (200) comprises a cam (202) for engaging the guide element (152). Drive device (100) according to one of the preceding claims 2 or 3, characterized in that the guide element (152) for guiding within the cam (202) is assigned to the motor shaft (150), wherein a stroke profile of the coupling element (200) depends on a rotation angle of the motor shaft (150) and a slope of the cam (202) of the coupling element (200). Drive device (100) according to one of the preceding claims, characterized in that the motor shaft (152) comprises a further guide element (154) for guiding within the cam (202). Drive device (100) according to one of the preceding claims, characterized in that the guide element (152) and the further guide element (154) are arranged opposite each other. Drive device (100) according to one of the preceding claims, characterized in that the interior (122) of the stator arrangement (120) is limited by an upper bearing element (124) and a lower bearing element (126). Drive device (100) according to claim 7, characterized in that the motor shaft (150) is mounted between the upper bearing element (124) and the lower bearing element (126). Drive device (100) according to one of the preceding claims 7 or 8, characterized in that the lower bearing element (126) has a contour (128) for engagement of the coupling element (200). Drive device (100) according to claim 9, characterized in that a rotation lock is formed by the engagement of the coupling element (200) in the contour (128). Drive device (100) according to one of the preceding claims 7 to 10, characterized in that the upper bearing element (124) is assigned a ball bearing for receiving axial forces. Drive device (100) according to claim 11, characterized in that the ball bearing has at least one ball which is located on the longitudinal axis (L). Drive device (100) according to one of the preceding claims, characterized in that the coupling element (200) is connected to an actuating element (220) for transferring a valve body (310) between an open position and a closed position. Valve, in particular air spring valve (300), with a drive device (100) according to one of claims 1 to 13.

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