Actuator

Abstract

An actuator (10) comprises a housing (20), a stator (31), a winding (33), coil terminals (61, 62), external connection terminals (63, 64), and intermediate terminals (65–68). The stator (31) is fixed to the housing (20). The winding (33) is wound around the stator (31). The coil terminals (61, 62) are electrically connected to the winding (33). The external connection terminals (63, 64) are held by the housing (20) and are electrically connected to the outside. The intermediate terminals (65–68) electrically connect the coil terminals (61, 62) and the external connection terminals (63, 64). A connection portion between the intermediate terminals (65–68) and at least one of the coil terminals (61, 62) and the external connection terminals (63, 64) is connected in a state in which a compressive load is applied.

Description

Actuator CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is based on Patent Application No. 2024-098761, filed June 19, 2024, the contents of which are incorporated herein by reference.

[0002] The present disclosure relates to actuators.

[0003] Conventionally, rotary actuators that are driven by switching the supply of current to a winding are known. For example, in Patent Document 1, motor terminals for electrically connecting the winding to the outside are inserted into a housing.

[0004] Japanese Patent Application Laid-Open No. 2022-11613

[0005] For example, when the motor windings and the motor terminals inserted into the housing are connected by bus bar terminals, there is a risk that displacement due to resonance of the internal parts or the housing will occur, which may cause stress in the motor windings and the terminals. An object of the present disclosure is to provide an actuator that can improve vibration durability.

[0006] The actuator of the present disclosure includes a housing, a stator, coil terminals, external connection terminals, and intermediate terminals. The stator is fixed to the housing. A winding is wound around the stator. The coil terminals are electrically connected to the winding. The external connection terminals are held in the housing and electrically connected to the outside. The intermediate terminals electrically connect the coil terminals to the external connection terminals.

[0007] The connection between the intermediate terminal and at least one of the coil terminal and the external connection terminal is made with a compressive load applied, thereby improving vibration durability.

[0008] The above and other objects, features, and advantages of the present disclosure will become more apparent from the following detailed description taken in conjunction with the accompanying drawings, in which Fig. 1 is a cross-sectional view of an actuator according to a first embodiment, Fig. 2 is a plan view showing the actuator according to the first embodiment with the rear housing and rotor assembly removed, Fig. 3 is a cross-sectional view taken along line III-III in Fig. 2, Fig. 4 is an explanatory diagram illustrating tensile and compressive loads applied to the bus bar terminal according to the first embodiment, Fig. 5 is a cross-sectional view of a motor terminal according to a second embodiment, Fig. 6 is a cross-sectional view of a motor terminal according to a third embodiment, Fig. 7 is a cross-sectional view of a motor terminal according to a fourth embodiment, Fig. 8 is a cross-sectional view of a motor terminal according to a fifth embodiment, and Fig. 9 is a cross-sectional view of a motor terminal according to a reference example, Fig. 10A is a cross-sectional view of a motor terminal according to a reference example in a state where a tensile load due to vibration is applied to the motor terminal, and Fig. 10B is an explanatory diagram illustrating tensile and compressive loads applied to the bus bar terminal according to the reference example.

[0009] First Embodiment An actuator according to the present disclosure will now be described with reference to the drawings. In the following, in a plurality of embodiments, substantially the same components are designated by the same reference numerals, and description thereof will be omitted.

[0010] The first embodiment is shown in Figures 1 to 4. As shown in Figures 1 and 2, the actuator 10 is a rotary actuator that includes a housing 20, a motor 30, and a reduction gear 40, and is used, for example, as a power source for a shift-by-wire system. Figure 2 is a view from the right side of Figure 1 with the rear housing 25 and rotor assembly removed.

[0011] The housing 20 has a front housing 21 and a rear housing 25. The front housing 21 is made of a resin or the like and includes a substantially cup-shaped main body 211 and a connector 212. A metal plate 22, a sensor terminal 23, and a cover terminal 63 (described later) are inserted into the front housing 21.

[0012] The rear housing 25 is formed in a generally cup shape, and is provided so that the openings thereof face the front housing 21. The rear housing 25 has a cylindrical protrusion 26 that protrudes on the side opposite the front housing 21. A holding plate 27 is embedded in the rear housing 25.

[0013] The rear housing 25 is formed with a flange portion 251. The flange portion 251 is formed with a hole portion 252 through which the screw 29 is inserted, and is provided with a collar 253. The front housing 21 and the rear housing 25 are fastened together with a bracket 28 by the screw 29. The actuator 10 is fixed to a transmission case (not shown) using the bracket 28.

[0014] The motor 30 includes a stator 31, a rotor 34, and the like, and is housed in the housing 20. The stator 31 is made up of multiple annular plates stacked in the thickness direction and fixed to the metal plate 22 by press fitting or the like. The stator 31 has multiple teeth (not shown). Multiple windings 33 are wound around the teeth of the stator 31. Ends of the windings 33 are connected to coil terminals 61, and are connected to cover terminals 63 inserted into the front housing 21 via bus bar terminals 65. Details of the terminal connections will be described later.

[0015] The rotor 34 is made up of multiple annular plates stacked in the thickness direction and fitted onto the radially outer side of the rotating shaft 37. The rotating shaft 37 is rotatably supported around the rotation axis AX1 by bearings 38 and 39. The motor-side bearing 38 is provided on the metal plate 22. The reducer-side bearing 39 is provided on the output member 44.

[0016] The reducer 40 has an eccentric shaft 41, a ring gear 42, an eccentric gear 43, and an output member 44. The eccentric shaft 41 is integral with the rotating shaft 37 so that its axis is an eccentric axis AX2 that is eccentric with respect to the rotation axis AX1. The ring gear 42 is disposed coaxially with the rotation axis AX1 and fixed to the rear housing 25. The eccentric gear 43 is a spur gear that meshes with the ring gear 42 and is supported by a bearing 48 provided on the eccentric shaft 41. As a result, the eccentric gear 43 is capable of planetary motion, rotating about the eccentric axis AX2 while revolving around the rotation axis AX1. The rotation speed of the eccentric gear 43 during planetary motion is variable relative to the rotation speed of the rotating shaft 37.

[0017] The output member 44 is disposed coaxially with the rotation axis AX1 and is rotatably supported by a bearing 49 provided in the rear housing 25. An engagement hole 445 corresponding to the engagement protrusion 435 is formed in the output member 44. The engagement protrusion 435 of the eccentric gear 43 is inserted into the engagement hole 445 of the output member 44, whereby the rotation of the eccentric gear 43 about the eccentric axis AX2 is transmitted to the output member 44.

[0018] In the actuator 10, a rotating magnetic field is generated by switching the energized phase of the winding 33, and the rotor 34 rotates due to the magnetic attractive or repulsive force generated by this rotating magnetic field. When the rotating shaft 37 and the eccentric shaft 41 rotate together with the rotor 34, the eccentric gear 43 performs planetary motion, and a rotation that is decelerated relative to the rotation of the rotor 34 is output from the output member 44.

[0019] A circuit board 50 is fixed to the front housing 21. A rotation angle sensor 51 is mounted on the circuit board 50 and connected to the sensor terminal 23. The rotation angle sensor 51 is provided in a position facing a magnet 54 that rotates integrally with the rotor 34, and detects the rotation angle of the rotor 34 by detecting the rotating magnetic field of the magnet 54.

[0020] 3, the motor terminal 60 includes a coil terminal 61, a cover terminal 63, and a bus bar terminal 65. The coil terminal 61 is formed by bending a plate-like conductive member into a substantially L-shape, and one end is connected to the winding 33. The coil terminal 61 is welded to the bus bar terminal 65 on the surface opposite the winding 33. In the drawing, the welded portion WL between the terminals is indicated by a matte finish.

[0021] The cover terminal 63 is a plate-shaped conductive member, and a middle portion thereof is inserted into the front housing 21. One end of the cover terminal 63 is provided in the connector portion 212 and is connectable to a power terminal of an external connector (not shown). The cover terminal 63 may be held in the housing in any manner, and is not limited to being embedded by an insert. The other end of the cover terminal 63 is exposed inside the main body portion 211 and welded to the bus bar terminal 65. In FIG. 3 and other figures, only the portion of the cover terminal 63 exposed from the front housing 21 is shown.

[0022] The bus bar terminal 65 is a plate-shaped conductive member, one end of which is connected to the coil terminal 61 and the other end of which is connected to the cover terminal 63. The bus bar terminal 65 has the coil terminal 61 welded to one surface thereof and the cover terminal 63 welded to the other surface thereof. This allows power to be supplied to the winding 33 via the coil terminal 61.

[0023] In the reference example shown in Fig. 9, the coil terminal 61 and the cover terminal 63 are connected to the bus bar terminal 65 without applying stress. In this state, when vibration is applied and the internal components and the housing resonate, the bus bar terminal 65 is displaced as shown in Fig. 10A, and tensile stress is generated in the welded portion WL as shown in Fig. 10B. By alleviating the stress caused by the resonance, the vibration durability of the motor terminal 60 can be improved.

[0024] 3, the distance Lt between the coil terminal 61 and the cover terminal 63 in the motor axial direction (i.e., the vertical direction on the paper surface of FIG. 3) is set to be equal to or less than the thickness Lb of the bus bar terminal 65 including the welded portion WL, and the bus bar terminal 65 is welded in a deflected state. In other words, the bus bar terminal 65 is connected to the coil terminal 61 and the cover terminal 63 in a state where it is forcibly displaced by elastic deformation.

[0025] The state in which the distance Lt between the coil terminal 61 and the cover terminal 63 is equal to or less than the plate thickness Lb of the bus bar terminal 65 includes a state in which the distance is negative, i.e., the welded portion on the cover terminal 63 side is located above the welded portion on the coil terminal 61 side in the plane of the paper in Figure 3, and the positions of the coil terminal 61 and the cover terminal 63 in the plate thickness direction overlap.

[0026] As shown in Fig. 4, the coil terminals 61 or the cover terminals 63 are connected to the bus bar terminals 65 with an initial compressive load applied. This relieves stress caused by displacement due to resonance, etc., and improves the vibration durability of the bus bar terminals 65 and the welded portions WL. Note that while Fig. 4 shows the connection points between the cover terminals 63 and the bus bar terminals 65, the same applies to the connection between the coil terminals 61 and the bus bar terminals 65.

[0027] As described above, the actuator 10 includes the housing 20, the stator 31, the winding 33, the coil terminals 61, the cover terminals 63, and the bus bar terminals 65. The stator 31 is fixed to the housing 20. The winding 33 is wound around the stator 31.

[0028] The coil terminal 61 is electrically connected to the winding 33. The cover terminal 63 is held in the housing 20 and electrically connected to the outside. The bus bar terminal 65 electrically connects the coil terminal 61 and the cover terminal 63. The welded portion WL between the bus bar terminal 65 and at least one of the coil terminal 61 and the cover terminal 63 is connected with a compressive load applied. This reduces tensile load due to vibration, etc., and improves the vibration durability of the motor terminal 60.

[0029] The bus bar terminal 65 is formed in a plate shape, and is connected to the coil terminal 61 at the front surface of one end and to the cover terminal 63 at the back surface of the other end. Note that the terms "front surface" and "back surface" are used merely as a formality to indicate that the surfaces are opposite each other. This allows a compressive load to be applied appropriately to the bus bar terminal 65.

[0030] The coil terminals 61 and the cover terminals 63 are provided at positions closer to or overlapping each other than the thickness Lb of the bus bar terminals 65 in the thickness direction of the bus bar terminals 65, and are connected in a state in which the bus bar terminals 65 are elastically deformed, thereby improving vibration durability.

[0031] Second and Third Embodiments A second embodiment is shown in Fig. 5, and a third embodiment is shown in Fig. 6. As in the second embodiment shown in Fig. 5, an initial compressive load may be applied to the welded portion WL by bending the bus bar terminal 66 at the bent portion 661 to form a step.

[0032] In Figure 6, the left side of the drawing shows the state before assembly, and the right side shows the state after assembly. In the third embodiment, the bus bar terminal 67, whose bent portion 671 is bent in advance, may be elastically deformed so that it becomes substantially linear when assembled with the coil terminal 61 and the cover terminal 63, and a compressive load may be applied to the welded portion WL. Even with this configuration, the tensile load during vibration can be reduced by being offset by the initial compressive load, thereby improving the vibration durability of the bus bar terminal 65. Even with this configuration, the same effects as those of the above embodiments can be achieved.

[0033] (Fourth and Fifth Embodiments) A fourth embodiment is shown in Fig. 7 and a fifth embodiment is shown in Fig. 8. In the fourth embodiment shown in Fig. 7, the coil terminal 62 has an inclined portion 621 that is inclined with respect to the plate thickness direction of the bus bar terminal 68, and is connected to the bus bar terminal 68 in a state in which the coil terminal 62 is elastically deformed in a direction that compresses the welded portion WL.

[0034] In the fifth embodiment shown in Fig. 8, the cover terminal 64 has an inclined portion 641 that is inclined with respect to the plate thickness direction of the bus bar terminal 68, and is connected to the bus bar terminal 68 in a state in which the cover terminal 64 is elastically deformed in a direction that compresses the welded portion WL. The coil terminal 62 and the cover terminal 64 may have different shapes and different positions of the connection points, as long as they can apply a compressive load to the welded portion WL. Even with this configuration, the same effects as the above-mentioned embodiments can be achieved.

[0035] In this embodiment, the cover terminals 63 and 64 correspond to "external connection terminals," the bus bar terminals 65 to 68 correspond to "intermediate terminals," and the welded portion WL corresponds to "connection portion."

[0036] In the above embodiment, the bus bar terminal is connected to the coil terminal on the front surface at one end thereof and to the cover terminal on the back surface at the other end thereof. In another embodiment, the connection between the coil terminal and the cover terminal and the bus bar terminal may be a connection form other than a double-sided connection, as long as a compressive load can be applied to the motor terminal.

[0037] In the above embodiment, the coil terminals and the bus bar terminals, and the cover terminals and the bus bar terminals are connected by welding. In other embodiments, the coil terminals or the cover terminals and the bus bar terminals may be connected by a method other than welding.

[0038] In the above embodiment, the actuator is applied to a drive source of a shift-by-wire system. In other embodiments, the actuator may be applied to an in-vehicle device other than a shift-by-wire system, or may be applied to a device other than an in-vehicle device. In addition, the gear configuration of the actuator or the reducer may be different. As described above, the present disclosure is not limited to the above embodiment and can be implemented in various forms without departing from the spirit thereof.

[0039] The present disclosure has been described based on the embodiments. However, the present disclosure is not limited to the embodiments and structures. The present disclosure also encompasses various modifications and variations within the scope of equivalents. Furthermore, various combinations and forms, as well as other combinations and forms including only one element, more than one element, or less than one element, are also within the scope and spirit of the present disclosure.

Claims

1. An actuator comprising: a housing (20); a stator (31) fixed to the housing; a winding (33) wound around the stator; coil terminals (61, 62) electrically connected to the winding; external connection terminals (63, 64) held in the housing and electrically connected to the outside; and intermediate terminals (65-68) electrically connecting the coil terminals and the external connection terminals, wherein the connection portions between the intermediate terminals and at least one of the coil terminals and the external connection terminals are connected with a compressive load applied.

2. The actuator according to claim 1, wherein the intermediate terminal is formed in a plate shape, and is connected to the coil terminal on the surface of one end side and to the external connection terminal on the back surface of the other end side.

3. An actuator as described in claim 2, wherein the coil terminal and the external connection terminal are arranged at positions closer to or overlapping each other than the thickness of the intermediate terminal in the thickness direction of the intermediate terminal, and are connected in a state in which the intermediate terminal is elastically deformed.

4. An actuator as described in claim 2, wherein the coil terminal (62) has an inclined portion (621) that is inclined in the thickness direction of the intermediate terminal, and is connected to the intermediate terminal in a state in which the coil terminal is elastically deformed in a direction that compresses the connection portion.

5. An actuator as described in claim 2, wherein the external connection terminal (64) has an inclined portion (641) inclined in the thickness direction of the intermediate terminal, and is connected to the intermediate terminal in a state in which the external connection terminal is elastically deformed in a direction that compresses the connection portion.

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