Electromechanical actuator

Abstract

The invention relates to an electromechanical actuator as a stepper motor adapter for a stepper motor for connection to a valve assembly, wherein a stepper motor shaft of the stepper motor dips into a driver, the rotational movement of which is directed to a change in the spring tension of a compression spring, which in turn acts directly or indirectly on a diaphragm or the like, wherein the stepper motor shaft is connected to a driver by a force-fit and form-fit connection, wherein the driver interacts with a transmission element which is guided translationally in an inner guide of the stepper motor adapter by means of a form-fit design.

Description

[0001] The invention relates to an electromechanical actuator for connection to a stepper motor and to a valve assembly.

[0002] EP 3 013 323 A1 discloses a pilot valve arrangement comprising a pilot valve device, a pilot valve element and a pilot valve seat.

[0003] The object of the invention is to provide an electromechanical actuating device for a stepper motor that operates maintenance-free and can be implemented cost-effectively.

[0004] The object of the invention is achieved by the features of claim 1. The dependent claims following claim 1 describe a further embodiment of the inventive concept.

[0005] The electromechanical actuator for stepper motors is designed to be mounted as a stepper motor adapter on pressure-variable valves or pilot valves. The stepper motor has a stepper motor shaft whose rotation is directed to change the force of a compression spring. This compression spring can act directly or indirectly on a diaphragm or equivalent device to achieve precise pressure setting at the valve. The stepper motor shaft is designed to engage with the stepper motor adapter via a positive-locking drive element. This drive element, in turn, engages a transmission element via a threaded connection. The transmission element is made of a maintenance-free plastic in which solid lubricants are embedded and which can be moved translationally through a recess in the stepper motor adapter.Such a plain bearing serves to prevent direct contact between the transmission element and an internal guide of the stepper motor adapter, thus preventing wear and ensuring flawless operation. Of course, it is also possible to use metal plain bearings.

[0006] The invention is explained in more detail below with reference to a possible, schematically illustrated embodiment. Fig. Figure 1 shows a sectional view of a stepper motor adapter; Fig. 2 a driver in a perspective view; Fig. 3 a transfer element in a perspective representation.

[0007] The sectional view of a stepper motor adapter 14 according to Fig. Figure 1 illustrates the interaction of the individual components. The stepper motor itself is not shown, nor is a valve to be controlled. The stepper motor adapter 14 has a free interior space in which a transmission element 6 is guided translationally by means of lateral guides. The transmission element 6 is shown in a rest position, i.e., it has no contact with, for example, a compression spring 3 located below it. The transmission element 6 has an internal thread 7, which interacts with an external thread 5 of a driver 4. This thread is designed as a fine thread.

[0008] A stepper motor axis 1 is connected to the driver 4 via a force-fit and form-fit, detachable connection. Such a connection can, for example, consist of the following: Fig. 2. Within the driver 4, there is a diametrically opposed recess on the upper side within a projection. It is important that the stepper motor shaft, with its end and a transverse element molded or arranged there, engages in the recess 9 without play. Only in this way can the stepper motor perform precise control adjustment via contact with the compression spring 3 on, for example, a diaphragm 13.

[0009] In the Fig. Figure 2 shows the driver 4 in detail. It is evident that the projection 8 of the driver 4 has a shoulder designed to accommodate a bearing 2 in the stepper motor adapter 14, ensuring smooth operation. The diametrical recess 9, located in or above a collar (not further specified), is also visible. The driver 4 is a turned part and features an external fine thread 5 below the collar.

[0010] One possible design of a transmission element 6 can be the Fig. 3. The transmission element 6 is also a turned part and has a lower diameter 18, which, in accordance with the compression spring 3, fits into it with clearance. Within the transmission element 6 is an internal fine thread 7, which, together with the external fine thread 5, enables the translational movement of the transmission element 6 within a recess 19 of the stepper motor adapter 14. The collar 17 has a diameter 10. In this preferred embodiment, the collar 17 is provided with lateral guide surfaces 11. The number of guide surfaces is arbitrary, but it must be adapted to the recess 19 within the stepper motor adapter 14. Because the transmission element 6 is made of a maintenance-free plastic, very good guidance within the recess 19 is ensured. Reference sign 1 stepper motor axis 2 warehouses 3 compression spring 4 drive wheels 5 external threads 6 transmission element 7 internal threads 8 Approach 9. In-depth study 10 diameter 11 guide surfaces 12 Inner guide 13 Membran 14 stepper motor adapters 15 flange 16 Actuating device 17 collars 18 diameter 19 Exclusion QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] EP 3 013 323 A1

[0002]

Claims

[1] Electromechanical actuating device as stepper motor adapter (14) for a stepper motor for connection to a valve device, wherein a stepper motor shaft (1) of the stepper motor dips into a driver (4), the rotational movement of which is directed to a change in the spring tension of a compression spring (3), which in turn acts directly or indirectly on a diaphragm (13) or the like, wherein the stepper motor shaft is connected to a driver (4) by a force-locking and form-locking connection, wherein the driver (4) cooperates with a transmission element (6) which is guided translationally in an inner guide (12) of the stepper motor adapter (14) by means of a form-locking design. [2] Actuating device according to claim 1, characterized by , that the stepper motor axis (1) is removable and immerses into the driver (4). [3] Actuating device according to claim 2, characterized by, that the stepper motor axis (1) has a connecting part at its end which engages in a diametrical recess (9) of the driver (4). [4] Actuating device according to one or more of the preceding claims, characterized by , that the driver (4) has an upper projection to which an outer diameter of smaller diameter (10) and an external thread (5) is attached. [5] Actuating device according to one or more of the preceding claims, characterized by , that the transmission element (6) has a bore with an internal thread (7) for the external thread (5). [6] Actuating device according to one or more of the preceding claims, characterized by , that the transmission element (6) is designed as a turned part with an upper, protruding collar (17), wherein the collar (17) is provided on the outside with at least one guide surface (11). [7] Actuating device according to claim 6, characterized bythat the collar (17) is provided with several, preferably four, guide surfaces (11). [8] Actuating device according to one or more of the preceding claims, characterized by , that the stepper motor adapter (14) has an internal recess (19) whose shape is adapted to the complementary formation of the collar (17). [9] Actuating device according to one or more of the preceding claims, characterized by , that the collar (17) can be subjected to a load by the rotational movement of the stepper motor axis (1) against the compression spring (3). [10] Actuating device according to one or more of the preceding claims, characterized by , that the transmission element (6) consists of a maintenance-free plastic containing solid lubricants. [11] Actuating device according to one or more of the preceding claims, characterized by , that the driver (4) is mounted within the stepper motor adapter (14) by means of a bearing (2).

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