Electric motor for an actuator and actuator having the same

Abstract

An electric motor (100) for an actuator is proposed. An electric motor (100) comprises a stator (11) having a ring (17) and a plurality of electromagnets (12), each having a coil core (16) and a coil (14) wound around the respective coil core (16); a rotor (13) which is arranged in the stator (11) and has a rotor shaft (18); and a bearing with a bearing shaft (20) for the gear (22). A plurality of electromagnets (12) are arranged side by side on a circular track having at least one arcuate opening (21). The bearing shaft (20) is arranged parallel to the rotor shaft (18) in the at least one arcuate opening (21). The invention further relates to a corresponding actuator.

Description

Technical Field

[0001] The invention relates to an electric motor for an actuator and such an actuator. Background Art

[0002] Electric motors are known per se and are widely used, for example in motor vehicles, for various purposes, for example as servomotors.

[0003] A flat electric motor is known from WO 2015 / 074940 A1, which is designed in particular for use in the field of medical devices. This document aims to provide an electric motor with high efficiency.

[0004] WO 2021 / 116029 A1 discloses a multiphase electric motor, in particular for use in electrically controlling a mechanical component, such as a clutch for a motor vehicle, as an alternative to hydraulic or pneumatic control solutions.

[0005] For the electrification of current hydraulic or pneumatic controls, high-power, robust, space-saving and compact actuators are required.

[0006] A space-saving electric motor is known from DE 10 2011 19 817 A1, but its height takes up more space than other known electric motors. Summary of the invention

[0007] The object of the present invention is therefore to provide an electric motor for an actuator which, while having sufficient power, takes up as little installation space as possible in all three spatial directions and at the same time offers a high degree of design freedom for the associated gears.

[0008] The above-mentioned object is achieved by an electric motor having the features of claim 1 and an actuator having the features of claim 13. Further features and details of the invention can be found in the dependent claims, the description and the drawings. Features and details described in connection with the electric motor according to the invention are of course also applicable in connection with the actuator according to the invention and vice versa, so that the disclosure of the individual inventive aspects is or can be referred to one another.

[0009] By means of the embodiments of the present invention, an improved electric motor can be provided in an advantageous manner. By means of such an electric motor, space, in particular the height space of the electric motor, can be effectively saved in corresponding applications without sacrificing too much power.

[0010] A first aspect of the present disclosure relates to an electric motor for an actuator. The electric motor comprises a stator having a ring and a plurality of electromagnets, each of which has a coil core and a coil wound around the corresponding coil core. The electric motor further comprises a rotor having a rotor shaft arranged in the stator and a bearing having a bearing shaft for a gear. The plurality of electromagnets are arranged side by side on a circular track. The circular track has at least one circular arc opening. The bearing shaft is arranged in the at least one circular arc opening parallel to the rotor shaft.

[0011] In other words, one or more electromagnets can be omitted in order to utilize the space occupied by one or more electromagnets so that the bearing shaft can be arranged therein. Thus, the distance between the bearing shaft and the rotor shaft in the radial direction can be smaller than the radius of the stator ring. Here, one electromagnet and / or only one coil can be omitted. In other words, the electromagnets can be arranged so that they form an open circle, wherein the opening of the circle is formed by the distance between two electromagnets and / or coils in the circumferential direction, which is greater than the distance between the remaining electromagnets and / or coils.

[0012] In the context of the present disclosure, a bearing for a gear wheel can be a shaft fixed to the stator and fixed in rotation thereon, on which the gear wheel is rotatably mounted, or a bearing bushing for a shaft fixedly connected to the gear wheel.

[0013] In the context of the present disclosure, the term bearing may be understood broadly. Thus, a bearing may refer to a housing for a shaft.

[0014] It is thereby achieved that the bearing shaft can accommodate a smaller gear wheel than in known electric motors and that the entire electric motor has a lower height or takes up less space in the z direction than in known electric motors, wherein the z direction runs parallel to the rotor shaft.

[0015] According to one embodiment of the electric motor, the at least one arc opening has an arc length corresponding to the tangential width of at least one coil, in particular exactly one coil or exactly two coils. In other words, exactly one coil or two coils with or without a corresponding coil core can be omitted, thereby providing space for a bearing with a bearing shaft.

[0016] Thus, a compact electric motor may be advantageously provided without significantly reducing or deteriorating the power of the electric motor.

[0017] In the context of the present disclosure, the tangential width is preferably the length of the arc of the coil or the maximum width of the coil. The coil generally has a truncated cone shape and is arranged to be wound around a coil core. Therefore, the coil preferably has a hole.

[0018] In particular, the coil can be configured as a truncated pyramid, wherein the edges of the truncated pyramid are rounded. Therefore, the tangential width of the coil can refer to the diameter or width of the bottom surface of the truncated cone or truncated pyramid of the coil. It should be noted that the envelope of the coil or truncated cone points to or towards the center of the stator ring.

[0019] According to one embodiment of the electric motor, the electric motor also has at least one coil core without coils. The at least one coil core without coils is arranged in the at least one circular arc opening. In other words, it can be provided that only the coils of the corresponding electromagnets are omitted. This can simplify the production of the electric motor in particular, since no changes need to be made in the production of the ring (compared to a stator with electromagnets arranged on a complete circular track).

[0020] According to one embodiment of the electric motor, the distance between the at least one coil-free coil core and an adjacent coil core is the same as the distance between two coil cores of the plurality of electromagnets.

[0021] According to one embodiment of the electric motor, the rotor axis coincides with the center of the ring of the stator.

[0022] According to one embodiment of the electric motor, the electromagnet and / or the plurality of coil cores of the at least one coil-free coil core are directed radially inwards from the inner side of the ring.

[0023] According to one embodiment of the electric motor, the ring of the stator is formed integrally with the coil core of the electromagnet and in particular with at least one coil-free coil core. The ring of the stator can be referred to as an iron ring. The coil core can be designed in the form of a web.

[0024] According to one embodiment of the electric motor, the circular track has two circular arc openings, which are arranged opposite to each other in the radial direction.

[0025] According to one embodiment of the electric motor, the stator is at least partially overmolded by the housing, in particular by the housing with plastic. In addition, the bearing for the associated gear is formed by means of the overmolding.

[0026] According to one embodiment of the electric motor, the electric motor further comprises at least one gear wheel. Compared with the gear wheels of known electric motors, the gear wheel can have a smaller diameter, so that the electric motor can be designed to be more compact.

[0027] According to one embodiment of the electric motor, the drive-side end of the rotor is configured as a pinion. Furthermore, the pinion meshes with the gear.

[0028] According to one embodiment of the electric motor, the rotor is rotatably arranged in the stator and has a multi-polar permanent magnet. The rotor is preferably supported in the housing. The bearing of the rotor can be formed, for example, by overmolding. Alternatively, the bearing can be formed by the housing itself (not overmolded).

[0029] A second aspect of the invention relates to an actuator having an electric motor and a transmission as described above and below.

[0030] It should be noted that the gear can belong to the electric motor or alternatively to the actuator. In other words, the actuator can have a gear. The transmission mechanism can preferably be driven by a pinion of the electric motor. The actuator can also include a circuit board with electrical and / or electronic components, which can be electrically connected to the stator.

[0031] All disclosures and advantages described above and below with respect to the electric motor according to the first aspect of the present disclosure are equally applicable to the actuator according to the second aspect of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The present invention will be described in detail below with reference to the accompanying drawings.

[0033] Figure 1 shows a top view of an electric motor according to one embodiment;

[0034] Figure 2 shows a perspective view of an electric motor according to one embodiment;

[0035] Figure 3 shows a perspective view of an electric motor according to one embodiment;

[0036] Figure 4 A perspective view showing an electric motor according to one embodiment; and

[0037] Figure 5 A perspective view of an electric motor is shown according to one embodiment. DETAILED DESCRIPTION

[0038] In the figures, similar, similarly acting, identical or identically acting elements are provided with similar or identical reference numerals. The figures are schematic only and are not true to scale.

[0039] Figure 1 The electric motor 100 for an actuator according to one embodiment is shown in a top view (ie viewed from above). In this case, the electric motor 100 has a gear 22. The gear 22 may alternatively be part of the actuator. Figure 1 The electric motor 100 is preferably a DC motor. The electric motor 100 comprises a stator 11 having a ring 17, in particular an iron ring, a rotor shaft 18 arranged in the stator 11 (although it is Figure 1 The rotor 13 is a rotor 18 (not shown in the figure, but usually a rotor shaft 18 protrudes from a pinion 24), and a plurality of electromagnets 12. In this example, a through hole is shown, through which the rotor shaft 18 is sunk. The rotor 13 is supported in a housing that is not shown. Alternatively, the rotor 13 can also be equipped with a shaft, which can also be supported in the housing. Figure 1 The electric motor 100 has in particular nine electromagnets 12. Each electromagnet 12 has a coil core 16 and a coil 14 wound around the respective coil core 16. The ring 17 is formed integrally with the web-shaped coil core 16. The electromagnets 12 are arranged side by side on a circular track having at least one circular arc opening 21. Figure 1 The circular track has in particular two arc openings 21. The two arc openings 21 are arranged opposite to each other in the radial direction of the stator 11. It should be noted that it is conceivable to provide a plurality of arc openings. The electric motor 100 also includes a bearing for a gear having a bearing shaft 20, which is arranged in at least one arc opening 21 parallel to the rotor shaft 18.

[0040] A pinion 24 is arranged on the rotor shaft 18. Within the scope of the invention, a pinion 24 is only assigned to the rotor 11. All other wheels of the associated transmission are referred to as gears. The electric motor 100 may also include a circuit board (not shown here). The circuit board includes circuits for controlling the coils 14 and thus the electromagnets 12 of the stator 11.

[0041] The electric motor 100 is also provided with three press-in contacts 23. Alternatively, contact lugs or contacts for soldering can also be used.

[0042] The first of the two arc openings 21 (e.g., the arc opening in which the bearing shaft 20 is arranged) has two coil cores 15 without coils. The second of the two arc openings 21 (e.g., the arc opening arranged in the radial direction relative to the first arc opening 21) has only one coil core 15 without coils. Providing the second arc opening 21 can advantageously improve the operation of the electric motor 100 or the actuator, because a smoother or more circular motion trajectory of the rotor 13 can be achieved thereby. However, the second (or additional) arc opening 21 is optional.

[0043] Figure 2 A perspective view of an electric motor 100 for an actuator according to one embodiment is shown. Figure 2 The electric motor 100 may be Figure 1An electric motor 100 is provided, in which the gear 22 is not shown. The bearing with the bearing shaft 20 for the gear 22 is located in the (first) circular arc opening 21. For this purpose, the two coils 14 of the two electromagnets 12 are omitted, so that two coil cores 15 without coils are arranged in the circular arc opening 21. By omitting the two coils 14 of the two electromagnets 12, sufficient space can be provided for the bearing shaft 20 between the two coil cores 15 without coils. In this way, the distance between the rotor shaft 18 and the bearing shaft 20 in the radial direction of the stator 11 or the electric motor 100 can be smaller than the radius of the ring 17 of the stator 11. In addition, by such an arrangement of the bearing shaft 20, the gear 22 can be arranged so that it occupies less space in the height of the electric motor 100, that is, in the axial direction of the stator 11, than the known electric motors.

[0044] The at least one (here first) arc opening 21 preferably has an arc length A, which corresponds to the tangential width B of the at least one coil 14. Figure 2 In the embodiment, the arc length A of the first arc opening 21 corresponds exactly to the tangential width B of two coils 14 , and the arc length of the second arc opening 21 corresponds exactly to the tangential width of exactly one coil 14 .

[0045] Figure 3 According to one embodiment, in particular according to Figure 1 and Figure 2 A perspective view of an alternative embodiment of an electric motor 100 is shown. Figure 3 In the electric motor 100, the arc opening 21 corresponds exactly to the space occupied by a coil 14 and the coil core 16. Figure 1 and Figure 2 Unlike the embodiment of the present invention, there is no coil core 15 without a coil in the arc opening 21. Therefore, in the present embodiment, only one electromagnet 12 is omitted instead of two electromagnets. Figure 1 and Figure 2 Therefore, Figure 3 The diameter of the bearing shaft 20 of the electric motor can be larger than Figure 1 and Figure 2 The diameter of the bearing shaft 20 of the electric motor is large. This allows the stability and reliability of the electric motor 100 to be improved.

[0046] Figure 4 and Figure 5 Each of the figures shows a perspective view of an electric motor 100 according to an exemplary embodiment. Figure 4 and Figure 5The stator 11 of the electric motor 100 is overmolded by a housing 19 made of plastic. The housing 19 can be a housing. The stator 11 is surrounded by the housing 19 except for three pressed-in contacts 23. Alternatively, it can be implemented that the inner diameter of the stator core is not overmolded by plastic. The housing 19 has a step, groove or notch 25 in the arc opening 21 of the circular track or above the arc opening 21. Such a step or groove of the housing 19 is used to arrange the gear 22 as close to the electromagnet 12 as possible in height, so that the electric motor is constructed as compact as possible in height.

[0047] As from Figure 5 It can be seen particularly clearly that the housing 19 can have a receiving opening 26 for receiving the rotor shaft 18 .

[0048] It should also be noted that the terms "comprising" and "having" do not exclude other elements, and the indefinite article "a" or "an" does not exclude a plurality. It should also be noted that the features and steps described with reference to one of the above embodiments may also be used in combination with other features and steps of other above embodiments. The reference signs in the claims should not be considered as limiting.

[0049] Reference numerals list

[0050] 100 Electric Motor

[0051] 11. Stator

[0052] 12 Electromagnet

[0053] 13 Rotor

[0054] 14 Coil

[0055] 15 Coil core without coil

[0056] 16 Coil core

[0057] 17 rings

[0058] 18 Rotor shaft

[0059] 19 Housing

[0060] 20 Bearing shaft

[0061] 21 Arc opening

[0062] 22 Gear

[0063] 23 Press-in contacts

[0064] 24 Small gear

[0065] 25 Notch

[0066] 26 Receiving hole

[0067] A Arc position of the arc opening

[0068] B Tangential width of coil

Claims

1. An electric motor (100) for an actuator, comprising: A stator (11) having a ring (17) and a plurality of electromagnets (12), each of which has a coil core (16) and a coil (14) wound around the corresponding coil core (16); a rotor (13) having a rotor shaft (18) arranged in the stator (11); and A bearing having a bearing shaft (20) for a gear (22), The plurality of electromagnets (12) are arranged side by side on a circular track, and the circular track has at least one circular arc opening (21), and The bearing shaft (20) is arranged in parallel with the rotor shaft (18) in the at least one circular arc opening (21).

2. The electric motor (100) according to claim 1, in, The at least one circular arc opening (21) has a circular arc length (A) corresponding to a tangential width (B) of at least one coil (14), in particular exactly one coil (14) or exactly two coils (14).

3. The electric motor (100) according to claim 1, It also includes at least one coil core (15) without a coil, in, The at least one coil-free coil core (15) is arranged in the at least one circular arc opening (21).

4. The electric motor (100) according to claim 3, in, The distance between the at least one coil-free coil core (15) and the adjacent coil core is the same as the distance between two coil cores (16) of the plurality of electromagnets (12).

5. The electric motor (100) according to claim 1, in, The rotor shaft (18) coincides with the center of the ring (17) of the stator (11).

6. The electric motor (100) according to one of the preceding claims, in, The electromagnet (12) and / or the plurality of coil cores (16) of the at least one coil-free coil core (15) are directed radially inwards from the inner side of the ring (17).

7. The electric motor (100) according to one of the preceding claims, in, The ring of the stator (11) is formed integrally with the coil core (16) of the electromagnet (12) and in particular with the at least one coil-free coil core (15).

8. The electric motor (100) according to one of the preceding claims, in, The circular track has two circular arc openings (21), and The two circular arc openings (21) are arranged opposite to each other in the radial direction.

9. The electric motor (100) according to one of the preceding claims, in, The stator (11) is at least partially overmolded by a housing (19), in particular by a housing (19) made of plastic, and a bearing for an associated gear wheel (22) is formed by means of the overmolding.

10. The electric motor (100) according to one of the preceding claims, in, The electric motor (100) also includes at least one gear (22).

11. The electric motor (100) according to one of the preceding claims, in, The drive-side end of the rotor (11) is configured as a pinion (24), and The pinion (24) is meshed with the gear (22).

12. The electric motor (100) according to one of the preceding claims, in, The rotor (13) is rotatably arranged in the stator (11) and includes a multi-polar permanent magnet.

13. An actuator comprising the electric motor (100) according to any one of claims 1 to 12 and a transmission mechanism.

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