Actuator

Abstract

To provide an actuator which can easily secure accuracy of a weld part of a cover terminal and a bus bar terminal.SOLUTION: An actuator 10 includes: a housing 20 including a resin-made cover 22; a bottomed cylindrical metal-made plate cover 30 inserted to the cover 22; a stator 41 which is press-fit into the inside of a cylindrical part 31 of the plate cover 30; a cover terminal 71 which is positioned on the side of a bottom part 32 of the plate cover 30 with respect to the stator 41, and is inserted to the cover 22; a bus bar terminal 75 which is fixed to the stator 41, and is welded to the cover terminal 71 in a state of being abutted on the cover terminal 71 in an axial direction; and a transmission suppression part 80 which is provided on the cover 22 and the plate cover 30, and suppresses transmission of force to the bottom part 32 from the cylindrical part 31 accompanied by press-fit of the stator 41. The transmission suppression part 80 includes a first support part 83, a second support part 84, and a plate receiving part 82.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an actuator. [Background technology]

[0002] A motor-driven actuator is known that includes a housing including a resin cover and a motor accommodated in the housing. In Patent Document 1, a cylindrical metal plate cover with a bottom is inserted into the resin cover, and a stator is fixed to the inside of the cylindrical portion of the plate cover. Cover terminals are inserted into the cover, and bus bar terminals are fixed to the stator. The bus bar terminals are welded to the cover terminals in axial contact with them. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2009-177982 Summary of the Invention [Problem to be solved by the invention]

[0004] To ensure the accuracy of the welds between the cover terminal and the busbar terminal, the height of the busbar terminal, i.e., the relative axial position of the busbar terminal to the cover terminal, is important. Currently, strict control of the relative position of the busbar terminal is essential to ensure the accuracy of the welds.

[0005] The present invention has been made in view of the above-mentioned points, and an object of the present invention is to provide an actuator that can easily ensure the accuracy of the welded joints between the cover terminal and the bus bar terminals. [Means for solving the problem]

[0006] The actuator of the present invention comprises a housing including a resin cover, a cylindrical metal plate cover with a bottom inserted into the cover, a stator press-fitted into the inside of the cylindrical portion of the plate cover, a cover terminal positioned on the bottom side of the plate cover relative to the stator and inserted into the cover, a bus bar terminal fixed to the stator and welded to the cover terminal while abutting the cover terminal in the axial direction, and a transmission suppression portion provided on at least one of the cover and the plate cover for suppressing the transmission of force from the cylindrical portion to the bottom portion due to the press-fitting of the stator.

[0007] The provision of such a transmission suppression portion suppresses deformation of the bottom surface of the bottom portion toward the stator due to press-fitting of the stator. This reduces variation in the axial relative position of the busbar terminals with respect to the cover terminals that are integral with the bottom portion. Therefore, it is possible to easily ensure the accuracy of the welds between the cover terminals and the busbar terminals without strictly controlling the relative positions of the busbar terminals. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 2 is a cross-sectional view of the actuator of the first embodiment. [Figure 2] FIG. 2 is a cross-sectional view schematically showing the cover, the plate cover, and the stator shown in FIG. [Figure 3] FIG. 3 is a view of the cover and plate cover of FIG. 2 as seen from direction III. [Figure 4] FIG. 10 is a cross-sectional view of an actuator according to a second embodiment. [Figure 5] FIG. 5 is a cross-sectional view schematically showing the cover, the plate cover, and the stator shown in FIG. 4. [Figure 6] The plate cover in Figure 5 is seen from direction VI. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, several embodiments of the actuator will be described with reference to the drawings. The same reference numerals will be used to designate substantially the same components among the embodiments, and the description thereof will be omitted.

[0010] [First embodiment] As shown in FIG. 1, the actuator 10 of the first embodiment is provided in a vehicle transmission and used as a power source for a shift-by-wire system.

[0011] The housing 20 has a resin case 21 and a cover 22. The case 21 and the cover 22 are fastened to each other with bolts 23 with their openings aligned. A cylindrical metal plate cover 30 with a bottom is inserted into the cover 22. The case 21 has a cylindrical protrusion 24 that protrudes on the side opposite the cover 22. A bracket 25 is fixed to the outer wall of the case 21. The bracket 25 is used to secure the actuator 10 to a vehicle transmission.

[0012] The motor 40 has a stator 41 and a rotor 42 housed in the housing 20. The stator 41 has a stator core 43 fixed to the plate cover 30 by press fitting, and a winding 44 provided on the stator core 43. The rotor 42 has a rotating shaft 47 rotatably supported about the rotation axis AX1 by a motor-side bearing 45 and a reducer-side bearing 46, and a rotor core 48 fitted onto and fixed to the rotating shaft 47.

[0013] The reducer 50 includes an eccentric shaft 51, a ring gear 52, an eccentric gear 53, an output member 54, and a transmission mechanism 55. The eccentric shaft 51 is disposed on an eccentric axis AX2 that is eccentric with respect to the rotation axis AX1, and is formed integrally with the rotation axis 47. The ring gear 52 is disposed coaxially with the rotation axis AX1 and fixed to the case 21. The eccentric gear 53 has external teeth 57 that mesh with internal teeth 56 of the ring gear 52, and is supported by a bearing 58 provided on the eccentric shaft 51 so as to be able to perform planetary motion. The planetary motion is a motion in which the eccentric gear 53 rotates about the eccentric axis AX2 while revolving around the rotation axis AX1. The rotation speed of the eccentric gear 53 during planetary motion is varied relative to the rotation speed of the rotation axis 47.

[0014] The output member 54 is disposed coaxially with the rotation axis AX1, and is rotatably supported by a bearing 59 provided in the case 21. The transmission mechanism 55 is composed of an engagement protrusion 61 formed on the eccentric gear 53 and an engagement hole 62 formed in the output member 54, and transmits the rotation of the eccentric gear 53 about the eccentric axis AX2 to the output member 54 by engagement between the engagement protrusion 61 and the engagement hole 62.

[0015] In the actuator 10, a rotating magnetic field is generated by switching the energized phase of the winding 44, and the rotor 42 rotates due to the magnetic attractive or repulsive force generated by this rotating magnetic field. When the eccentric shaft 51 rotates around the rotation axis AX1 together with the rotor 42, the eccentric gear 53 performs planetary motion, and the rotation of the eccentric gear 53, which has been decelerated relative to the rotation of the rotor 42, is output from the output member 54.

[0016] Next, the cover 22 and various terminals will be described with reference to Figures 1 to 3. Hereinafter, the direction parallel to the rotation axis AX1 will be referred to as the "axial direction." Furthermore, the direction perpendicular to the rotation axis AX1 will be referred to as the "radial direction." Furthermore, the direction around the rotation axis AX1 will be referred to as the "circumferential direction."

[0017] The cover 22 is formed in a cylindrical shape with a bottom, and has a cylindrical cover portion 26 and a cover bottom portion 27. The cylindrical cover portion 26 is provided with a connector 28 and a plurality of flanges 29 that protrude radially outward. The plate cover 30 is inserted so as to fit the shape of the cover 22.

[0018] In addition to the plate cover 30, a cover terminal 71 is inserted into the cover 22. The cover terminal 71 is located on the bottom 32 side of the plate cover 30 relative to the stator 41, and extends from the bottom 32 through the cylindrical portion 31 to the connector 28. Terminals 72 on the bottom 32 side of the cover terminal 71 are exposed inside the housing 20. The plate cover 30 has terminal through-holes 33 through which the terminals 72 are inserted.

[0019] The winding 44 is wound around an insulator 73. A bus bar 74 is fixed to the insulator 73. The bus bar 74 has a bus bar terminal 75 connected to the winding 44. The bus bar terminal 75 is welded to the cover terminal 71 in a state of axial contact with the cover terminal 71.

[0020] Here, the assembly of the cover 22 and the stator 41 will be described. The stator 41 is press-fitted into the inside of the cylindrical portion 31 of the plate cover 30. During this press-fitting, the bus bar terminals 75 move axially together with the stator 41. When the stator 41 is press-fitted up to the press-fit end, the bus bar terminals 75 come into axial contact with the cover terminals 71. Thereafter, the bus bar terminals 75 are welded to the cover terminals 71.

[0021] In the conventional configuration, the stator 41 was supported on the resin surface of the cover 22, which meant that the relative axial position of the bus bar terminals 75 with respect to the cover terminal 71 was prone to variation. In addition, when the stator 41 was press-fitted, the cylindrical portion 31 was deformed radially, causing the bottom portion 32 to deform and rise toward the stator 41. This meant that strict control of the relative position of the bus bar terminals 75 was essential to ensure accuracy in the terminal welds.

[0022] In the first embodiment, in order to ensure the accuracy of the terminal welds, a transmission suppression portion 80 is provided that suppresses the transmission of force from the cylindrical portion 31 to the bottom portion 32 when the stator 41 is press-fitted. The transmission suppression portion 80 includes a support portion 81 and a plate receiving portion 82.

[0023] The support portion 81 is provided on the plate cover 30 and has a first support portion 83 and a second support portion 84. The first support portion 83 is formed to extend radially inward from the end of the cylindrical portion 31 on the bottom portion 32 side. In this embodiment, the first support portion 83 extends parallel to the end face 49 of the stator 41 and is formed in an overall annular shape. The first support portion 83 has a stator abutment surface 85 perpendicular to the axial direction. The stator abutment surface 85 is exposed inside the housing 20. The stator 41 is in surface contact with the stator abutment surface 85. Corners 86 between the cylindrical portion 31 and the first support portion 83 are formed to be rounded so that a cross section passing through the rotation axis AX1 (hereinafter referred to as a longitudinal cross section) has an arc shape. The stator 41 has chamfered portions 87 that avoid interference with the corners 86.

[0024] The second support portion 84 is formed to extend from the radially inner end of the first support portion 83 toward the bottom portion 32. In the first embodiment, the second support portion 84 extends perpendicular to the end face 49 of the stator 41 and is formed in an overall cylindrical shape. In a vertical cross section, the angle between the first support portion 83 and the second support portion 84 is 90 degrees, and the first support portion 83 and the second support portion 84 form a crank shape. The cylindrical portion 31, the first support portion 83, the second support portion 84, and the bottom portion 32 are integrally molded from metal.

[0025] The plate receiving portion 82 is provided on the cover 22. The cover 22 has a cover cylindrical portion 26 located radially outward from the cylindrical portion 31, and the plate receiving portion 82 located radially outward from the second support portion 84. The plate receiving portion 82 is arranged on the opposite side of the stator 41 from the first support portion 83 in the axial direction. A radial thickness t1 of the plate receiving portion 82 is formed to be thicker than a radial thickness t2 of the cover cylindrical portion 26.

[0026] (effect) As described above, in the first embodiment, the actuator 10 includes the transmission suppression unit 80. The transmission suppression unit 80 suppresses the transmission of force from the tubular portion 31 to the bottom portion 32 that occurs when the stator 41 is press-fitted. The provision of such a transmission suppression unit 80 suppresses deformation of the bottom surface of the bottom portion 32 that causes the stator 41 to be pressed into place, such that the bottom surface of the bottom portion 32 is lifted toward the stator 41. This reduces variation in the axial relative position of the bus bar terminals 75 with respect to the cover terminals 71 that are integrally provided with the bottom portion 32. Therefore, it is possible to easily ensure the accuracy of the welds between the cover terminals 71 and the bus bar terminals 75 without strictly controlling the relative position of the bus bar terminals 75.

[0027] In the first embodiment, the transmission suppression portion 80 includes a first support portion 83 extending radially inward from the cylindrical portion 31, and a second support portion 84 extending from the first support portion 83 toward the bottom portion 32. The cylindrical portion 31, the first support portion 83, the second support portion 84, and the bottom portion are integrally formed from metal. This suppresses deformation of the plate cover 30 when the stator 41 is press-fitted, and improves the axial positional accuracy of the terminals 72 of the cover terminal 71.

[0028] In the first embodiment, the first support portion 83 has a stator abutment surface 85 that is perpendicular to the axial direction. The stator 41 is in surface contact with the stator abutment surface 85. The first support portion 83 is made of metal, which can improve the dimensional accuracy of the stator abutment surface 85, thereby further improving the positioning accuracy of the bus bar terminals 75 after the stator 41 is press-fitted.

[0029] In the first embodiment, the cover 22 has a cover tubular portion 26 located radially outward from the tubular portion 31, and a plate receiving portion 82 located radially outward from the second support portion 84. The plate receiving portion 82 is formed to have a radial thickness greater than that of the cover tubular portion 26, and constitutes the transmission suppression portion 80. As a result, the increased rigidity of the cover 22 due to the increased amount of resin below the plate cover 30 suppresses deformation of the cover 22 when the stator 41 is press-fitted, and the axial positional accuracy of the terminals 72 of the cover terminal 71 is further improved.

[0030] Furthermore, in the first embodiment, the stator 41 has a chamfered portion 87 that avoids interference with a corner 86 between the tubular portion 31 and the first support portion 83. In a vertical cross section, the angle formed between the first support portion 83 and the second support portion 84 is 90 degrees or more. This increases the amount of resin below the plate cover 30, thereby increasing the rigidity of the cover 22. This makes it possible to suppress deformation of the cover 22 when the stator 41 is press-fitted.

[0031] [Second embodiment] 4 to 6, in the second embodiment, a lightening portion 91, which is a hole penetrating in the axial direction, and a connection portion 92 that connects the bottom portion 32 and the tubular portion 31 are provided at the connection point between the tubular portion 31 and the bottom portion 32. The cover 22 has a stator support portion 93 that penetrates from the side opposite the stator 41 with respect to the bottom portion 32 through the lightening portion 91 toward the stator 41. The stator 41 abuts against the stator support portion 93 in the axial direction.

[0032] The cutout portion 91 is formed so as to have a circumferential length longer than that of the connecting portion 92. The cutout portion 91 constitutes the transmission suppression portion 80, and suppresses the transmission of force from the tubular portion 31 to the bottom portion 32 caused by press-fitting of the stator 41. Therefore, the actuator 10 according to the second embodiment has the same effects as the first embodiment.

[0033] [Other embodiments] In other embodiments, the cover may not have the plate support portion of the first embodiment. That is, the radial thickness of the portion of the cover located radially outward from the second support portion may be equal to the radial thickness of the portion of the cover located radially outward from the cylindrical portion. However, as long as the cover includes the first support portion and the second support portion, it is possible to suppress the transmission of force from the cylindrical portion to the bottom portion due to the press-fitting of the stator.

[0034] In other embodiments, the stator may contact the resin surface of the plate cover instead of the metal surface of the cover. However, as long as the first support portion and the second support portion are provided, it is possible to suppress the transmission of force from the cylindrical portion to the bottom portion due to the press-fitting of the stator.

[0035] In other embodiments, the angle between the first support portion and the second support portion in the longitudinal cross section does not have to be 90 degrees. The second support portion may be formed in a tapered shape, for example, so that the inner diameter becomes smaller toward the bottom side.

[0036] The present invention is not limited to the above-described embodiment, and can be implemented in various forms without departing from the spirit of the invention. [Explanation of symbols]

[0037] 10 actuator, 20 housing, 22 cover, 30 plate cover, 31 cylindrical portion, 32 bottom portion, 41 stator, 71 cover terminal, 75 bus bar terminal, 80 transmission suppression portion.

Claims

1. a housing including a resin cover; a cylindrical metal plate cover with a bottom inserted into the cover; a stator press-fitted into the cylindrical portion of the plate cover; a cover terminal positioned on the bottom side of the plate cover relative to the stator and inserted into the cover; a bus bar terminal fixed to the stator and welded to the cover terminal in an axial contact with the cover terminal; a transmission suppression portion provided on at least one of the cover and the plate cover, the transmission suppression portion suppressing transmission of force from the cylindrical portion to the bottom portion due to press-fitting of the stator; An actuator comprising:

2. the transmission suppression portion includes a first support portion extending radially inward from the cylindrical portion and a second support portion extending from the first support portion toward the bottom portion, The actuator according to claim 1 , wherein the cylindrical portion, the first support portion, the second support portion, and the bottom portion are integrally formed from metal.

3. the first support portion has a stator abutment surface perpendicular to the axial direction, The actuator according to claim 2 , wherein the stator is in surface contact with the stator contact surface.

4. the cover has a cover cylindrical portion located radially outward from the cylindrical portion and a plate receiving portion located radially outward from the second support portion, The plate receiving portion has a radial thickness greater than that of the cover tubular portion, The actuator according to claim 2 , wherein the transmission suppression portion includes the plate receiving portion.

5. the stator has a chamfered portion that avoids interference between the cylindrical portion and a corner of the first support portion, 5. The actuator according to claim 4, wherein an angle formed between the first support portion and the second support portion is equal to or greater than 90 degrees in a cross section passing through a rotation axis of the stator.

6. Between the cylindrical portion and the bottom portion, a lightening portion which is a hole penetrating in the axial direction, and a connecting portion which connects the bottom portion and the cylindrical portion are provided, the cover has a stator receiving portion that penetrates the bottom portion from the opposite side of the stator to the stator side through the lightening portion and abuts against the stator, the hollowed portion has a circumferential length greater than that of the connecting portion, The actuator according to claim 1 , wherein the transmission suppression portion includes the hollowed portion.

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