JP7059551B2 - Electric actuator - Google Patents

Description

The present invention relates to an electric actuator.

Conventionally, the electric actuator is provided with a breathing passage for alleviating a pressure change inside the case (see Patent Document 1).

Japanese Unexamined Patent Publication No. 9-112101

In the conventional electric actuator, a breathing passage is provided inside the case to alleviate the pressure change inside the case while preventing water from entering, or a breathing passage is provided so as to project outward from the case, so that the case itself becomes large. Was there.

One aspect of the present invention is to provide an electric actuator provided with a breather and capable of suppressing an increase in size of the device.

According to the first aspect of the present invention, a case including a motor having a motor shaft extending along a central axis, a deceleration mechanism connected to one side of the motor shaft in the axial direction, and the motor and the deceleration mechanism. The case includes, the case body for accommodating the motor and the deceleration mechanism, the legs extending radially outward from the case body, and the inside and outside of the case protruding radially outward from the case body. The case has a breather portion having a breathing hole for connecting the motors, and the first case accommodating the motor and the second case accommodating the deceleration mechanism and having the legs each have an opening. The breather portion has a configuration in which the breather portion is fixed so as to face each other in the axial direction, and has a first portion provided in the first case and a second portion provided in the second case. The leg portion has a plate shape having a plate surface facing the axial direction, a second portion of the breather portion is arranged on a surface facing the other side in the axial direction of the leg portion, and the breather portion is a shaft of the breather portion. An electric actuator is provided that has a tubular portion that protrudes from a surface facing the other side in the direction toward the other side in the axial direction, and the tubular portion has the breathing hole.

According to the aspect of the present invention, there is provided an electric actuator provided with a breather and capable of suppressing an increase in size of the device.

FIG. 1 is a perspective view showing an electric actuator of the present embodiment. FIG. 2 is a vertical sectional view showing the electric actuator of the present embodiment. FIG. 3 is a cross-sectional view showing a section III-III of FIG. 2, which is a view of the deceleration mechanism facing one side in the axial direction.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
As shown in FIGS. 1 and 2, the electric actuator 10 of the present embodiment includes a case 11, a motor 20, a reduction mechanism 30, an output unit 40, a first bearing 51, a second bearing 54, and a second bearing. It includes 3 bearings 55 and a 4th bearing 56. The motor 20 includes a rotor 22, a stator 23, a control board 70, and a rotation detection unit 75. The rotor 22 has a motor shaft 21 extending along the first central axis (central axis) J1. That is, the motor 20 has a motor shaft 21. The deceleration mechanism 30 is connected to the motor shaft 21. The output unit 40 has an output shaft unit 41 to which the rotation of the motor shaft 21 is transmitted via the deceleration mechanism 30. The output shaft portion 41 extends in the axial direction of the first central axis J1. The output shaft portion 41 is arranged at an axial position different from the axial position where the motor shaft 21 is arranged. In the example of this embodiment, the axial direction of the first central axis J1 is the vertical direction.

In the present embodiment, the direction parallel to the first central axis J1 is simply referred to as "axial direction". Of the axial directions, the direction from the motor shaft 21 toward the output shaft portion 41 is referred to as one side in the axial direction, and the direction from the output shaft portion 41 toward the motor shaft portion 21 is referred to as the other side in the axial direction. One side in the axial direction is a direction from the motor 20 toward the reduction mechanism 30 and the output unit 40 along the first central axis J1. The other side in the axial direction is the direction from the output unit 40 and the deceleration mechanism 30 toward the motor 20 along the first central axis J1. In the example of this embodiment, one side in the axial direction is the lower side, and the lower side in FIGS. 1 and 2. The other side in the axial direction is the upper side, which is the upper side in FIGS. 1 and 2. It should be noted that the upper side and the lower side are simply names for explaining the relative positional relationship of each part, and the actual arrangement relationship or the like may be an arrangement relationship or the like other than the arrangement relationship or the like indicated by these names. ..

The radial direction centered on the first central axis J1 is simply referred to as "diameter direction". Of the radial directions, the direction approaching the first central axis J1 is referred to as the radial inner side, and the direction away from the first central axis J1 is referred to as the radial outer direction. The circumferential direction centered on the first central axis J1 is simply called "circumferential direction".

The case 11 houses the motor 20, the deceleration mechanism 30, and the output unit 40. The case 11 has a motor case 12 as a first case and a deceleration mechanism case 13 as a second case. The motor case 12 and the reduction mechanism case 13 are made of resin. That is, the case 11 is made of resin. As shown in FIG. 2, the motor case 12 has a first opening 12i that opens on one side in the axial direction. The speed reduction mechanism case 13 has a second opening 13j that opens on the other side in the axial direction. The case 11 has a configuration in which the motor case 12 and the deceleration mechanism case 13 are fixed in a state where the openings thereof face each other in the axial direction. That is, the motor case 12 and the deceleration mechanism case 13 are fixed to each other with the first opening 12i and the second opening 13j facing each other in the axial direction. In a state where the motor case 12 and the speed reduction mechanism case 13 are fixed to each other, the inside of the first opening 12i and the inside of the second opening 13j communicate with each other.

The motor case 12 houses the motor 20 and the third bearing 55. The motor case 12 has a peripheral wall portion 12a, a lid body 12g, a partition wall portion 12d, a bearing holding portion 12e, and a connector portion 12c.

The peripheral wall portion 12a has a cylindrical shape extending in the axial direction about the first central axis J1. The peripheral wall portion 12a has a cylindrical shape. The peripheral wall portion 12a is open at one end in the axial direction. The peripheral wall portion 12a has an opening on the other end in the axial direction. The axial one surface and the axial other surface of the peripheral wall portion 12a are opened respectively. That is, the peripheral wall portion 12a opens on both sides in the axial direction. The peripheral wall portion 12a covers the periphery of the first central axis J1 along the first central axis J1.

The stator 23 is housed in the peripheral wall portion 12a. The peripheral wall portion 12a surrounds the radially outer side of the stator 23. The inside of the peripheral wall portion 12a is divided into a portion on one side in the axial direction and a portion on the other side in the axial direction by a partition wall portion 12d described later. Of the inside of the peripheral wall portion 12a, the portion on one side in the axial direction from the partition wall portion 12d is the stator accommodating portion. Of the inside of the peripheral wall portion 12a, the portion on the other side in the axial direction from the partition wall portion 12d is the control board accommodating portion 12f. In the example of this embodiment, the inner diameter of the control board accommodating portion 12f is larger than the inner diameter of the stator accommodating portion.

As shown in FIGS. 1 and 2, the lid body 12g has a plate shape. The lid 12g closes the opening of the peripheral wall portion 12a that opens on the other side in the axial direction. The lid body 12g closes the opening on the other side in the axial direction of the control substrate accommodating portion 12f. The lid body 12g is detachably attached to the peripheral wall portion 12a by using a screw 16.

As shown in FIG. 2, the partition wall portion 12d has an annular plate shape extending radially inward from the inner peripheral surface of the peripheral wall portion 12a. The partition wall portion 12d covers the stator 23 from the other side in the axial direction. The partition wall portion 12d is located between the rotor 22 and the stator 23 and the control board 70. The partition wall portion 12d is arranged between the rotor 22 and the stator 23 along the axial direction and the control board 70. The partition wall portion 12d is provided with a through hole that penetrates the partition wall portion 12d in the axial direction. For example, a coil wire or the like is passed through the through hole. The coil wire extends from the coil of the stator 23 described later, passes through the through hole, and is electrically connected to the control board 70.

The bearing holding portion 12e has a tubular shape. The bearing holding portion 12e extends in the axial direction about the first central axis J1. The bearing holding portion 12e is provided at the radial inner edge portion of the partition wall portion 12d. A third bearing 55 is fixed to the inner peripheral surface of the bearing holding portion 12e. The bearing holding portion 12e holds the third bearing 55.

As shown in FIG. 1, the connector portion 12c projects radially outward from the outer peripheral surface of the peripheral wall portion 12a. The connector portion 12c has a tubular shape extending in the radial direction. The connector portion 12c opens radially outward. In the example of this embodiment, the connector portion 12c has a long cylindrical shape. The shape of the opening of the connector portion 12c is an oval shape in which the length in the circumferential direction is longer than the length in the axial direction. The connector portion 12c holds the bus bar 80, which will be described later. The connector portion 12c is a portion to be connected to the electrical wiring outside the case 11. An external power supply (not shown) is connected to the connector portion 12c.

As shown in FIG. 3, the motor case 12 has a first wiring holding portion 14. The first wiring holding portion 14 projects radially outward from the peripheral wall portion 12a. A first wiring member 91 extending from the control board 70 is arranged in the first wiring holding portion 14.

The deceleration mechanism case 13 accommodates the deceleration mechanism 30, the output unit 40, the second wiring member 92 (see FIG. 3), the first bearing 51, the second bearing 54, and the fourth bearing 56. As shown in FIGS. 1 and 2, the speed reduction mechanism case 13 includes a bottom wall portion 13a, a support cylinder portion 13d, a protruding cylinder portion 13c, a cover cylinder portion 13b, a second wiring holding portion 15, and a leg portion. It has 13 m and.

As shown in FIG. 2, the bottom wall portion 13a has an annular plate shape centered on the first central axis J1. The bottom wall portion 13a covers the deceleration mechanism 30 from one side in the axial direction. The surface of the bottom wall portion 13a facing the other side in the axial direction faces the deceleration mechanism 30 in the axial direction. The bottom wall portion 13a is a portion of the inner surface of the case 11 located on one side in the axial direction of the speed reduction mechanism 30. The bottom wall portion 13a is provided with a support cylinder portion 13d. The support cylinder portion 13d has a tubular shape that protrudes from the surface of the bottom wall portion 13a facing the other side in the axial direction to the other side in the axial direction. The support cylinder portion 13d has a cylindrical shape. The support cylinder portion 13d extends from the radial inner edge portion of the bottom wall portion 13a to the other side in the axial direction. The support cylinder portion 13d opens on the other side in the axial direction.

The protruding tubular portion 13c has a tubular shape that protrudes from the radial inner edge portion of the bottom wall portion 13a to one side in the axial direction. The output shaft portion 41 is arranged in the protruding cylinder portion 13c. The cover cylinder portion 13b has a tubular shape that protrudes from the radial outer edge portion of the bottom wall portion 13a to the other side in the axial direction. The cover cylinder portion 13b has a cylindrical shape. The cover cylinder portion 13b opens on the other side in the axial direction. The cover cylinder portion 13b covers the periphery of the first central axis J1 along the first central axis J1. The end portion of the cover cylinder portion 13b on the other side in the axial direction is in contact with and fixed to the end portion of the peripheral wall portion 12a on the other side in the axial direction.

As shown in FIG. 3, the second wiring holding portion 15 projects radially outward from the cover cylinder portion 13b. The inside of the second wiring holding portion 15 communicates with the inside of the cover cylinder portion 13b. The axial position of the end portion of the second wiring holding portion 15 on one side in the axial direction is the same as the axial position of the bottom wall portion 13a. The second wiring holding portion 15 faces the first wiring holding portion 14 in the axial direction. The inside of the second wiring holding portion 15 communicates with the inside of the first wiring holding portion 14.

As shown in FIGS. 1 and 3, the leg portion 13m projects radially outward from the cover cylinder portion 13b. A plurality of leg portions 13m are provided on the outer peripheral surface of the cover cylinder portion 13b at intervals in the circumferential direction. In the example of this embodiment, the three legs 13m are arranged at equal intervals in the circumferential direction. Further, the protruding lengths of the three legs 13m from the cover cylinder 13b are different from each other. The electric actuator 10 can be attached to an object such as a vehicle by using the leg portion 13 m.

As shown in FIGS. 1 and 2, the case 11 has a breather portion 17. That is, the case 11 has a cylindrical case body 11A extending in the axial direction, a leg portion 13 m extending radially outward from the case body 11A, and a breather portion 17 projecting radially outward from the case body 11A. The case body 11A is a cylindrical portion of the case 11 that houses the motor 20 and the deceleration mechanism 30.

The breather portion 17 has a breathing hole 17a that connects the inside and the outside of the case 11. As shown in FIG. 2, the breather portion 17 has a first portion 17A provided in the motor case 12 and a second portion 17B provided in the speed reduction mechanism case 13.

The first portion 17A projects radially outward from the motor case 12. The first portion 17A has a plate-shaped portion 171 extending in a direction orthogonal to the axial direction, and a cylindrical portion 172 extending from the plate surface of the plate-shaped portion 171 to the other side in the axial direction. The first portion 17A has a breathing hole 17a including a through hole that axially penetrates the plate-shaped portion 171 and the tubular portion 172. Since the breathing hole 17a is a through hole extending in the axial direction, when the motor case 12 is manufactured by resin molding, the breathing hole 17a can be provided without a separate processing step, and the breathing hole 17a can be manufactured efficiently.

The second portion 17B projects radially outward from the cover cylinder portion 13b of the speed reduction mechanism case 13. The second portion 17B has a breather peripheral wall 173 extending in the circumferential direction and connected to the cover cylinder portion 13b, and a breather bottom wall 174 surrounded by the breather peripheral wall 173. The second portion 17B is provided on the leg portion 13m as shown in FIGS. 2 and 3. In the case of the present embodiment, the leg portion 13m provided with the second portion 17B has a plate shape extending in the radial direction and extending in a direction orthogonal to the axial direction. The leg portion 13 m has a shape that becomes thinner toward the outer side in the radial direction. The second portion 17B is located between the outer side side 131 and the outer side side 132 of the leg portion 13 m extending along the radial direction when viewed in the axial direction.

The first portion 17A and the second portion 17B face each other in the axial direction, and the plate-shaped portion 171 of the first portion 17A contacts the end surface of the second portion 17B of the breather peripheral wall 173 facing the other side in the axial direction. That is, the first portion 17A and the second portion 17B face each other with their end faces facing in the axial direction. According to this configuration, the case body 11A and the breather portion 17 can be assembled by combining the motor case 12 and the deceleration mechanism case 13 so as to face each other in the axial direction along the motor shaft 21. It can be assembled without complicated operations and can be manufactured efficiently.

The area surrounded by the plate-shaped portion 171 and the breather peripheral wall 173 and the breather bottom wall 174 becomes an air passage 175. The air passage 175 is connected to the inside of the case 11. As shown in FIG. 2, the air passage 175 is opened at one end in the axial direction of the breathing hole 17a. The breathing hole 17a connects the inside and the outside of the case 11. Therefore, each of the first portion 17A and the second portion 17B has an air passage communicating with the inside of the case 11.

According to this configuration, the breather portion 17 projecting radially from the motor case 12 when viewed in the axial direction is arranged in the plane region of the leg portion 13 m. Therefore, it is possible to realize the electric actuator 10 provided with the breather portion 17 without increasing the occupied area.
Further, since the breather portion 17 is configured to use a part of the leg portion 13m as an air passage, it is possible to suppress the occupied space in the axial direction.

In the first portion 17A, a waterproof sheet 176 capable of ventilating is arranged in the opening on the inner side of the case 11 of the breathing hole 17a. The waterproof sheet 176 is a porous member that allows air to pass through but does not allow water droplets to pass through. As the waterproof sheet 176, for example, a liquid-repellent treated non-woven fabric is used.
The breather portion 17 is composed of a first portion 17A and a second portion 17B that can be divided in the axial direction, and by arranging the waterproof sheet 176 on the inner surface of the first portion 17A, the waterproof sheet 176 can be installed in the manufacturing process. It will be easier.

As shown in FIG. 2, the rotor 22 includes a motor shaft 21, a rotor core 22a, a rotor magnet (not shown), and a balance weight 24. The motor shaft 21 is rotatably supported around the first central axis J1 by the first bearing 51 and the third bearing 55. The first bearing 51 is fitted to one end of the motor shaft 21 on one side in the axial direction. The third bearing 55 is fitted to a portion of the motor shaft 21 on the other side in the axial direction. The motor shaft 21 and the reduction mechanism 30 are rotatably connected to each other around the second central axis J2 via the fourth bearing 56. The fourth bearing 56 is arranged between the first bearing 51 and the third bearing 55 along the axial direction and is fitted to the motor shaft 21. The first bearing 51, the third bearing 55 and the fourth bearing 56 are, for example, ball bearings. The end of the motor shaft 21 on the other side in the axial direction protrudes from the inside of the bearing holding portion 12e toward the other side in the axial direction. The end portion of the motor shaft 21 on the other side in the axial direction protrudes toward the other side in the axial direction with respect to the partition wall portion 12d.

The motor shaft 21 has a rotor core fixed shaft portion 21a, an eccentric shaft portion 21b, and a weight mounting shaft portion 21c. The rotor core fixed shaft portion 21a extends in the axial direction about the first central shaft J1. The rotor core is fixed to the outer peripheral surface of the rotor core fixing shaft portion 21a. A third bearing 55 is fitted to a portion of the rotor core fixed shaft portion 21a located on the other side in the axial direction from the rotor core 22a.

The eccentric shaft portion 21b is located on one side in the axial direction with respect to the rotor core fixed shaft portion 21a. The eccentric shaft portion 21b is eccentric with respect to the first central shaft J1. As shown in FIG. 3, the eccentric shaft portion 21b extends about the second central shaft J2 that is eccentric with respect to the first central shaft J1. The second central axis J2 is parallel to the first central axis J1. Therefore, the eccentric shaft portion 21b extends in the axial direction. The inner diameter side of the fourth bearing 56 is fitted to the eccentric shaft portion 21b. The eccentric shaft portion 21b rotatably supports the external tooth gear 31 described later of the reduction mechanism 30 via the fourth bearing 56.

The weight mounting shaft portion 21c is arranged between the rotor core fixed shaft portion 21a and the eccentric shaft portion 21b along the axial direction. The weight mounting shaft portion 21c is connected to the eccentric shaft portion 21b from the other side in the axial direction. The weight mounting shaft portion 21c has a diameter larger than that of the eccentric shaft portion 21b. The weight mounting shaft portion 21c is arranged adjacent to the other side in the axial direction of the fourth bearing 56, and the one end portion in the axial direction of the weight mounting shaft portion 21c faces the inner ring of the fourth bearing 56 in the axial direction. .. The balance weight 24 is attached to the weight attachment shaft portion 21c.

The rotor core 22a has a tubular shape and is fixed to the outer peripheral surface of the rotor core fixing shaft portion 21a. The rotor magnet is fixed to the outer peripheral surface of the rotor core 22a. The stator 23 faces the rotor 22 with a radial gap. The stator 23 has an annular stator core that surrounds the radially outer side of the rotor 22 and a plurality of coils mounted on the stator core. Although not shown, the stator core has a back yoke and teeth. The back yoke is an annular shape extending in the circumferential direction. A plurality of teeth extend radially inward from the back yoke and are arranged at intervals in the circumferential direction.

The control board 70 has a plate shape. The plate surface of the control board 70 faces in the axial direction and extends perpendicular to the axial direction. The control board 70 is housed in the control board accommodating portion 12f. The control board 70 is arranged on the other side of the partition wall portion 12d in the axial direction. In the example of this embodiment, the control board 70 is arranged away from the partition wall portion 12d on the other side in the axial direction. The control board 70 is electrically connected to the stator 23. The coil wire of the coil of the stator 23 is connected to the control board 70. For example, an inverter circuit is mounted on the control board 70.

The bus bar 80 is held by the connector portion 12c. The bus bar 80 is embedded in the connector portion 12c. Of both ends of the bus bar 80, the first end is fixed to the control board 70. As shown in FIG. 1, the second end portion of both ends of the bus bar 80 is arranged in the radial outer opening of the connector portion 12c and is exposed to the outside of the case 11. The bus bar 80 is electrically connected to an external power source connected to the connector portion 12c. Power is supplied from an external power source to the coil of the stator 23 through the bus bar 80 and the control board 70.

The rotation detection unit 75 detects the rotation of the rotor 22. As shown in FIG. 2, the rotation detection unit 75 is arranged in the control board accommodating unit 12f. The rotation detection unit 75 is arranged in the space between the partition wall portion 12d and the control board 70. The rotation detection unit 75 has a magnet fixed to the motor shaft 21 and a rotation sensor mounted on the control board 70.

The deceleration mechanism 30 is connected to a portion of the motor shaft 21 on one side in the axial direction. The deceleration mechanism 30 is arranged on the radial outer side of a portion of the motor shaft 21 on one side in the axial direction. The deceleration mechanism 30 is arranged at a position overlapping the eccentric shaft portion 21b when viewed from the radial direction. The deceleration mechanism 30 is arranged between the bottom wall portion 13a along the axial direction and the stator 23.

As shown in FIGS. 2 and 3, the reduction mechanism 30 includes an external tooth gear 31, an internal tooth gear 33, and an annular plate portion 40c. The external tooth gear 31 has a substantially annular plate shape centered on the second central axis J2. The plate surface of the external tooth gear 31 faces the axial direction and spreads perpendicularly to the axial direction. A gear portion is provided on the outer peripheral surface of the external tooth gear 31. The external tooth gear 31 is connected to the eccentric shaft portion 21b via the fourth bearing 56. That is, the reduction mechanism 30 is connected to the motor shaft 21 via the fourth bearing 56. The fourth bearing 56 is fitted in the external tooth gear 31. The fourth bearing 56 rotatably connects the motor shaft 21 and the external tooth gear 31 around the second central axis J2.

The external tooth gear 31 has a plurality of pins 32. The pin 32 is a columnar shape protruding from the surface of the external tooth gear 31 facing one side in the axial direction to one side in the axial direction. The plurality of pins 32 are arranged at equal intervals along the circumferential direction about the second central axis J2. In the example of this embodiment, eight pins 32 are provided.

The internal tooth gear 33 surrounds the radial outer side of the external tooth gear 31 and is fixed to the reduction mechanism case 13. The internal tooth gear 33 is an annular shape centered on the first central axis J1. The internal tooth gear 33 is arranged in the recessed portion 13n on the inner peripheral surface of the cover cylinder portion 13b and is fixed to the cover cylinder portion 13b. The recessed portion 13n is located at the end of the inner peripheral surface of the cover cylinder portion 13b on the other side in the axial direction, and opens on the other side in the axial direction and inward in the radial direction.

The internal tooth gear 33 meshes with the external tooth gear 31. A gear portion is provided on the inner peripheral surface of the internal tooth gear 33. The gear portion of the internal tooth gear 33 meshes with the gear portion of the external tooth gear 31. The gear portion of the internal tooth gear 33 meshes with the gear portion of the external tooth gear 31 in a part in the circumferential direction (the left portion of each of FIGS. 2 and 3). The number of teeth in the gear portion of the internal tooth gear 33 and the number of teeth in the gear portion of the external tooth gear 31 are different from each other. The number of teeth in the gear portion of the internal tooth gear 33 is larger than the number of teeth in the gear portion of the external tooth gear 31.

The annular plate portion 40c is a part of the output portion 40. The annular plate portion 40c is a connecting portion that connects the deceleration mechanism 30 and the output portion 40. As shown in FIG. 2, the annular plate portion 40c is arranged on one side in the axial direction of the external tooth gear 31. The annular plate portion 40c has an annular plate shape centered on the first central axis J1. The radially outer portion of the annular plate portion 40c is located on the other side in the axial direction than the radially inner portion. The radially outer portion of the annular plate portion 40c is thicker in the axial direction than the radially inner portion of the annular plate portion 40c. The annular plate portion 40c has a plurality of holes 40d that penetrate the annular plate portion 40c in the axial direction. The hole 40d is arranged in the radial outer portion of the annular plate portion 40c.

As shown in FIG. 3, the plurality of holes 40d are arranged at equal intervals along the circumferential direction about the first central axis J1. In the example of this embodiment, eight holes 40d are provided. The number of holes 40d is the same as the number of pins 32. The hole 40d has a circular hole shape. The inner diameter of the hole 40d is larger than the outer diameter of the pin 32. A plurality of pins 32 are inserted into the plurality of holes 40d. The outer peripheral surface of the pin 32 is inscribed with the inner peripheral surface of the hole 40d. That is, the outer peripheral surface of the pin 32 and the inner peripheral surface of the hole 40d come into contact with each other at a part of the peripheral surface. The inner peripheral surface of the hole 40d supports the external tooth gear 31 so as to be swingable via the pin 32.

The output unit 40 is a portion that outputs the driving force of the electric actuator 10. As shown in FIG. 2, the output unit 40 includes a tubular wall portion 40b, an annular plate portion 40c, and an output shaft portion 41. The tubular wall portion 40b has a cylindrical shape extending in the axial direction about the first central axis J1. The tubular wall portion 40b has a cylindrical shape extending in one axial direction from the radial inner edge portion of the annular plate portion 40c. The tubular wall portion 40b has a bottomed cylindrical shape that opens on the other side in the axial direction. The first bearing 51 is fitted to the end on one side in the axial direction on the inner peripheral surface of the cylindrical wall portion 40b. As a result, the first bearing 51 rotatably connects the motor shaft 21 and the output unit 40 to each other. The first bearing 51 connects the motor shaft 21 and the output unit 40 so as to be relatively rotatable around the first central axis J1. Inside the cylindrical wall portion 40b, an end portion on one side in the axial direction of the motor shaft 21 is located. The end face of the motor shaft 21 facing one side in the axial direction faces the surface of the bottom of the tubular wall portion 40b facing the other side in the axial direction with a gap.

The cylindrical wall portion 40b is arranged in the support tubular portion 13d. A second bearing 54 is arranged between the cylindrical wall portion 40b and the support tubular portion 13d. A second bearing 54 is fitted to the support cylinder portion 13d. That is, the second bearing 54 is fitted in the support cylinder portion 13d. A tubular wall portion 40b is fitted in the second bearing 54. The second bearing 54 is sandwiched between the outer peripheral surface of the tubular wall portion 40b and the inner peripheral surface of the support tubular portion 13d. The second bearing 54 rotatably supports the output unit 40 with respect to the case 11.

The output shaft portion 41 extends in the axial direction and is arranged on one side in the axial direction of the motor shaft 21. The output shaft portion 41 has a columnar shape centered on the first central axis J1. The output shaft portion 41 extends from the bottom portion of the tubular wall portion 40b to one side in the axial direction. The output shaft portion 41 is inserted into the protruding cylinder portion 13c. The portion of the output shaft portion 41 on one side in the axial direction protrudes from the protruding cylinder portion 13c on one side in the axial direction. Another member that outputs the driving force of the electric actuator 10 is attached to a portion of the output shaft portion 41 on one side in the axial direction. In the present embodiment, the output unit 40 is a single member.

When the motor shaft 21 is rotated around the first central axis J1, the eccentric shaft portion 21b (second central axis J2) revolves around the first central axis J1 in the circumferential direction. The revolution of the eccentric shaft portion 21b is transmitted to the external tooth gear 31 via the fourth bearing 56, and the external tooth gear 31 revolves around the first central axis J1 in the internal tooth gear 33. The external tooth gear 31 swings while changing the inscribed position between the inner peripheral surface of the hole 40d and the outer peripheral surface of the pin 32. At this time, the position where the gear portion of the external tooth gear 31 and the gear portion of the internal tooth gear 33 mesh with each other changes in the circumferential direction. The number of teeth of the external tooth gear 31 and the number of teeth of the internal tooth gear 33 are different from each other, and the internal tooth gear 33 is fixed to the reduction mechanism case 13 and does not rotate. Therefore, the external tooth gear 31 rotates around the second central axis J2 with respect to the internal tooth gear 33.

The direction in which the external tooth gear 31 rotates is opposite to the direction in which the motor shaft 21 rotates. The rotation (rotation) of the external tooth gear 31 around the second central axis J2 is transmitted to the annular plate portion 40c via the hole 40d and the pin 32. As a result, the annular plate portion 40c rotates around the first central axis J1, and the output portion 40 rotates around the first central axis J1. In this way, the rotation of the motor shaft 21 is transmitted to the output shaft portion 41 via the reduction mechanism 30.

The rotation of the output unit 40 is decelerated with respect to the rotation of the motor shaft 21 by the deceleration mechanism 30. Specifically, in the reduction mechanism 30 of the present embodiment, the reduction ratio R of the rotation of the output unit 40 with respect to the rotation of the motor shaft 21 is represented by R = − (N2-N1) / N2. The minus sign at the beginning of the right side of the equation representing the reduction ratio R indicates that the rotation direction of the output unit 40 to be decelerated is opposite to the rotation direction of the motor shaft 21. N1 is the number of teeth of the external tooth gear 31, and N2 is the number of teeth of the internal tooth gear 33. As an example, when the number of teeth N1 of the external gear 31 is 59 and the number of teeth N2 of the internal gear 33 is 60, the reduction ratio R is -1/60. As described above, the deceleration mechanism 30 of the present embodiment can increase the reduction ratio R of the rotation of the output unit 40 with respect to the rotation of the motor shaft 21. As a result, the rotational torque of the output unit 40 can be increased.

The present invention is not limited to the above-described embodiment, and the configuration can be changed without departing from the spirit of the present invention, for example, as described below.

In the above-described embodiments and modifications, the output unit 40 is a single member, but is not limited thereto. For example, the annular plate portion 40c and the cylindrical wall portion 40b of the output portion 40 and the output shaft portion 41 may be fixed by welding or the like.
The deceleration mechanism 30 may have a function of increasing torque by decelerating the rotation of the motor shaft 21 and transmitting it to the output unit 40, and is not limited to the configuration described in the above-described embodiment.

In addition, as long as it does not deviate from the gist of the present invention, each configuration (component) described in the above-described embodiments, modifications, and notes may be combined, and additions, omissions, substitutions, and the like of the configurations may be combined. It can be changed. Further, the present invention is not limited by the above-described embodiments, but is limited only by the scope of claims.

10 ... electric actuator, 11 ... case, 11A ... case body, 13m ... leg, 17 ... breather part, 17a ... breathing hole, 17A ... first part, 17B ... second part, 20 ... motor, 21 ... motor shaft, 30 ... Deceleration mechanism, 176 ... Waterproof sheet, J1 ... First central axis (central axis)

Claims (4)

With a motor having a motor shaft extending along the central axis,
A deceleration mechanism connected to one side in the axial direction of the motor shaft,
A case accommodating the motor and the deceleration mechanism, and
Equipped with
The case is
A case body that houses the motor and the deceleration mechanism,
The legs extending radially outward from the case body,
A breather portion having a breathing hole that protrudes radially outward from the case body and connects the inside and the outside of the case,
Have,
The case has a configuration in which a first case accommodating the motor and a second case accommodating the deceleration mechanism and having the legs are fixed with their openings facing each other in the axial direction. death,
The breather portion has a first portion provided in the first case and a second portion provided in the second case.
The leg portion has a plate shape having a plate surface facing the axial direction, and has a plate shape.
The second portion of the breather portion is arranged on the surface of the leg portion facing the other side in the axial direction.
The breather portion has a tubular portion that protrudes from the surface of the breather portion facing the other side in the axial direction to the other side in the axial direction.
The tubular portion has the breathing hole.
Electric actuator.
The first portion and the second portion of the breather portion face each other with their end faces facing in the axial direction.
The electric actuator according to claim 1. The first part of the breather part is
A plate-shaped portion protruding radially outward from the motor case,
The cylindrical portion extending from the plate surface of the plate-shaped portion to the other side in the axial direction, and the tubular portion.
The breathing hole, which is a through hole that penetrates the tubular portion in the axial direction,
The electric actuator according to claim 1 or 2. The electric actuator according to claim 3, wherein a breathable waterproof sheet is arranged in the opening of the through hole located inside the case.

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