Actuator

Abstract

To shorten a shaft from a rotation part to an axial displacement part.SOLUTION: An actuator 10 comprises a stator 12 that generates a rotating magnetic field, which is formed annularly. The actuator 10 further comprises: a shaft 36 rotated when the stator 12 generates the rotating magnetic field, which is formed using a soft magnetic material, and arranged on a radially inner side with respect to the stator 12, and to which a magnet 38 is provided. The actuator 10 further comprises: a linear motion part 18 axially displaced via rotation of the shaft 36, which is provided at a rotation center portion of the shaft 36.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to actuators. [Background technology]

[0002] The following Patent Document 1 discloses a disconnector device that is provided in a vehicle and switches between a state in which the vehicle can run in two-wheel drive and a state in which the vehicle can run in four-wheel drive. In this disconnector device, the differential shaft and the hub are separated or connected depending on the running conditions, so that the vehicle can switch between a state in which the vehicle can run in two-wheel drive and a state in which the vehicle can run in four-wheel drive. In detail, the disconnector device includes a ball screw shaft that rotates when a motor is operated, a nut connected to the ball screw shaft, a sleeve that moves together with the nut, and a fork engaged with the sleeve. The ball screw shaft is rotated by the operation of the motor, and the nut moves the fork via the sleeve, so that the differential shaft and the hub are connected or the connection between the differential shaft and the hub is released. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 7225353 Summary of the Invention [Problem to be solved by the invention]

[0004] From the standpoint of mountability on a vehicle, it is desirable to be able to shorten the shaft length from a rotating part such as a motor to an axially displaceable part such as a nut, but the configuration described in Patent Document 1 above leaves room for improvement in this regard.

[0005] In consideration of the above, an object of the present disclosure is to provide an actuator capable of shortening the shaft length from the rotating part to the axially displaceable part. [Means for solving the problem]

[0006] An actuator (10, 48, 50, 52) that solves the above problems includes a stator (12) formed in an annular shape and generating a rotating magnetic field, a shaft (36) formed of a soft magnetic material, arranged radially inward of the stator and equipped with a magnet (38), and rotated when the stator generates a rotating magnetic field, and an axial displacement portion (18) provided at the rotation center of the shaft and displaced in the axial direction when the shaft rotates.

[0007] By configuring in this manner, it is possible to shorten the shaft length from the rotating portion to the axially displaceable portion. [Brief description of the drawings]

[0008] [Figure 1] 1 is a cross-sectional view showing a cross section of an actuator according to a first embodiment taken along an axial direction. [Diagram 2] FIG. 4 is a front view showing an engagement portion between the fork and the main shaft. [Diagram 3] 6 is a cross-sectional view showing a cross section of an actuator according to a second embodiment taken along an axial direction. FIG. [Figure 4] FIG. 11 is a cross-sectional view showing a cross section of an actuator according to a third embodiment taken along an axial direction. [Diagram 5] FIG. 11 is a cross-sectional view showing a cross section of an actuator according to a fourth embodiment taken along an axial direction. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] (First embodiment) An actuator 10 according to a first embodiment of the present disclosure will be described with reference to Figures 1 and 2. Note that the arrow Z direction, the arrow R direction, and the arrow C direction appropriately shown in the figures respectively indicate one side in the rotational axial direction, the outer side in the rotational radial direction, and one side in the rotational circumferential direction of a rotor 16 described below. In addition, hereinafter, when the axial direction, radial direction, and circumferential direction are simply indicated, they refer to the rotational axial direction, rotational radial direction, and rotational circumferential direction of the rotor 16 unless otherwise specified.

[0010] 1, an actuator 10 of this embodiment includes a stator 12 that generates a rotating magnetic field, and a housing 14 that accommodates the stator 12 and the like. The actuator 10 also includes a rotor 16 that rotates when the stator 12 generates a rotating magnetic field, and a linear motion part 18 that serves as an axial displacement part that is displaced in the axial direction when the rotor 16 rotates. The actuator 10 also includes a fork 20 that serves as a transmission part and is connected to the linear motion part 18.

[0011] The stator 12 includes a stator core 22 formed in an annular shape and a plurality of coils 24 formed around the stator core 22. A rotating magnetic field is generated around the stator 12 by switching the energization of the plurality of coils 24. The stator 12 is supported by the housing 14, which will be described later, by, for example, pressing the stator core 22 into the housing 14.

[0012] The housing 14 is formed in a cylindrical shape penetrating in the axial direction. The housing 14 includes a stator support portion 14A on which the stator 12 is supported on the radially inner side. The housing 14 also includes a bearing support portion 14B on which the bearing 26 is supported on the radially inner side. The bearing support portion 14B is disposed adjacent to the stator support portion 14A on one axial side of the stator support portion 14A, and has a smaller diameter than the stator support portion 14A. The housing 14 also includes an oil seal support portion 14C on which the oil seal 28 is supported on the radially inner side. The oil seal support portion 14C is disposed adjacent to the bearing support portion 14B on one axial side of the bearing support portion 14B, and has a smaller diameter than the bearing support portion 14B. A control portion 30 and a housing cover 32 for controlling the supply of electricity to the stator 12 (the multiple coils 24) are provided on the other axial side of the housing 14. The other axial side of the housing 14 is closed by the control portion 30 and the housing cover 32. In addition, a bearing 34 is fixed to the housing cover 32 .

[0013] The rotor 16 includes a shaft 36 formed of a soft magnetic material such as steel, and a magnet 38 provided on the shaft. The shaft 36 includes a large diameter portion 36A disposed radially inward relative to the stator 12. The shaft 36 also includes a medium diameter portion 36B that protrudes from the large diameter portion 36A toward one axial side and has an outer diameter set smaller than that of the large diameter portion 36A. The shaft 36 also includes a small diameter portion 36C that protrudes from the large diameter portion 36A toward the other axial side and has an outer diameter set smaller than that of the medium diameter portion 36B. The portion of the medium diameter portion 36B adjacent to the large diameter portion 36A is supported by the bearing 26, and the end of the small diameter portion 36C on the other axial side is supported by the bearing 34. This allows the shaft 36 to rotate with the bearings 26 and 34 as support shafts. The magnet 38 is fixed to the radially outer surface of the large diameter portion 36A. The magnet 38 may be a segment magnet divided in the circumferential direction, or may be a ring magnet formed in an annular shape. The magnet 38 may be configured to be provided on the inner periphery of the large diameter portion 36A. A linear motion portion insertion hole 36D into which the linear motion portion 18 described later is inserted from one axial side is formed at the rotation center of the large diameter portion 36A and the medium diameter portion 36B. One axial end of the linear motion portion insertion hole 36D is opened to one axial side at the end face on one axial side of the medium diameter portion 36B. The other axial end of the linear motion portion insertion hole 36D is closed inside the large diameter portion 36A. A first screw portion 36E is formed along the axial direction on the inner periphery of the linear motion portion insertion hole 36D.

[0014] The linear motion portion 18 is formed using a rod-shaped steel material. A second screw portion 18A is formed along the axial direction on the outer periphery of the linear motion portion 18. The linear motion portion 18 is inserted into the linear motion portion insertion hole 36D of the shaft 36 with the second screw portion 18A and the first screw portion 36E screwed together.

[0015] As shown in FIG. 1 and FIG. 2, the fork 20 is disposed on the radial outer periphery of the medium diameter portion 36B of the shaft 36. The fork 20 includes a slide support portion 20A slidably supported on the medium diameter portion 36B of the shaft 36, and a main shaft engagement portion 20B protruding radially outward from the slide support portion 20A. The slide support portion 20A is formed with a slide hole 20C into which the medium diameter portion 36B of the shaft 36 is inserted. The inner peripheral surface of the slide hole 20C slides against the outer peripheral surface of the medium diameter portion 36B, so that the fork 20 can move (displace) in the axial direction along the medium diameter portion 36B of the shaft 36. The main shaft engagement portion 20B of the fork 20 engages with a main shaft 40 that constitutes a part of the mechanism that is the control target of the actuator 10 of this embodiment. This allows power to be transmitted from the fork 20 to the control target.

[0016] The fork 20 is connected to the linear motion part 18 via a connecting member 42. The connecting member 42 has a first connecting part 42A fixed to one axial end of the linear motion part 18 via a fastening member 44. The connecting member 42 has a second connecting part 42B extending from a radially outer end of the first connecting part 42A toward the other axial side. The other axial end of the second connecting part 42B is fixed to the fork 20 via a fastening member 46. This allows the fork 20 to move in the axial direction together with the linear motion part 18 and the connecting member 42.

[0017] (Actions and Effects of the Present Embodiment) Next, the operation and effects of this embodiment will be described.

[0018] As shown in FIG. 1 and FIG. 2, in the actuator 10 of the present embodiment described above, when the rotor 16 rotates toward one circumferential side by generating a rotating magnetic field by the stator 12, the shaft 36 rotates toward one circumferential side relative to the linear moving part 18. Here, the first screw part 36E on the shaft 36 side and the second screw part 18A on the linear moving part 18 side are screwed together. Therefore, when the shaft 36 rotates toward one circumferential side relative to the linear moving part 18, the linear moving part 18 moves (displaces) toward one axial side relative to the shaft 36. On the other hand, when the rotor 16 rotates toward the other circumferential side by generating a rotating magnetic field by the stator 12, the shaft 36 rotates toward the other circumferential side relative to the linear moving part 18, and the linear moving part 18 moves toward the other axial side relative to the shaft 36. Then, in the actuator 10 of the present embodiment, the fork 20 can be moved axially along the main shaft 40 by moving the linear moving part 18 in the axial direction. This makes it possible to control the controlled object.

[0019] Here, in the actuator 10 of this embodiment, the linear motion part 18 is configured to be inserted into the rotation center part of the shaft 36. In this configuration, compared to a configuration in which the linear motion part 18 is disposed on an axial extension of the shaft 36, it is possible to shorten the axial length of the range from the shaft 36, which is the rotating part, to the linear motion part 18.

[0020] In addition, in this embodiment, the fork 20 is slidably supported on the medium diameter portion 36B of the shaft 36. This configuration makes it unnecessary to provide a part whose only function is to support the fork 20. As a result, it is possible to prevent the number of parts of the actuator 10 from increasing and the configuration from becoming complicated.

[0021] Furthermore, in this embodiment, the fork 20 engages with the main shaft 40, thereby preventing the linear motion part 18 from rotating in the circumferential direction. This configuration makes it unnecessary to provide a part whose only function is to prevent the linear motion part 18 from rotating in the circumferential direction. As a result, it is possible to prevent the number of parts of the actuator 10 from increasing and the configuration from becoming complicated.

[0022] In this embodiment, the magnet 38 is provided on the large diameter portion 36A of the shaft 36. This allows the large diameter portion 36A of the shaft 36 to function as a rotor core of the rotor 16. With this configuration, it is possible to suppress an increase in the number of parts of the rotor 16, compared to a rotor in which the rotor core is fixed to the shaft.

[0023] In addition, in this embodiment, the stator support portion 14A, the bearing support portion 14B, and the oil seal support portion 14C of the housing 14 are arranged adjacent to each other in the axial direction, so that the stator 12, the bearing 26, and the oil seal 28 are arranged adjacent to each other in the axial direction. By arranging the stator 12, the bearing 26, and the oil seal 28 closely in the axial direction in this manner, it is possible to reduce the size of the actuator 10 in the axial direction.

[0024] Second embodiment Next, an actuator 48 according to a second embodiment will be described with reference to Fig. 3. Note that in the actuator 48 according to the second embodiment, members and parts corresponding to those of the actuator 10 described above are denoted by the same reference numerals as those of the actuator 10 described above, and descriptions thereof may be omitted.

[0025] As shown in FIG. 3, the shaft 36 of the actuator 48 of this embodiment includes a medium diameter portion 36B that protrudes from the large diameter portion 36A toward one axial side and the other axial side. The fork 20 is disposed on the radial outer periphery of the medium diameter portion 36B of the shaft 36. A linear motion portion insertion hole 36D into which the linear motion portion 18 is inserted is formed in the rotation center of the large diameter portion 36A and the medium diameter portion 36B. An end portion on one axial side of the linear motion portion insertion hole 36D is opened to one axial side at an end face on one axial side of the medium diameter portion 36B on one axial side. An end portion on the other axial side of the linear motion portion insertion hole 36D is opened to the other axial side at an end face on the other axial side of the medium diameter portion 36B on the other axial side. That is, the linear motion portion insertion hole 36D is configured to penetrate the rotation center of the shaft 36 in the axial direction.

[0026] In the actuator 48 of the present embodiment described above, a linear motion unit 18 that is longer than that of the previously described actuator 10 can be provided at the rotation center of the shaft 36. As a result, in the actuator 48 of the present embodiment, the axial movement range of the linear motion unit 18 and the fork 20 can be increased compared to the previously described actuator 10.

[0027] Third embodiment Next, an actuator 50 according to a third embodiment will be described with reference to Fig. 4. Note that in the actuator 50 according to the third embodiment, members and parts corresponding to those of the actuator 10 described above are denoted by the same reference numerals as those of the actuator 10 described above, and descriptions thereof may be omitted.

[0028] 4, in the actuator 50 of this embodiment, the fork 20 is disposed on the radial outer periphery of the large diameter portion 36A of the shaft 36 and on the radial outer periphery of the stator support portion 14A of the housing 14. The fork 20 is slidably supported by the stator support portion 14A of the housing 14. More specifically, the stator support portion 14A of the housing 14 is inserted into the slide hole 20C of the slide support portion 20A. The inner peripheral surface of the slide hole 20C slides against the outer peripheral surface of the stator support portion 14A, allowing the fork 20 to move axially along the stator support portion 14A of the housing 14.

[0029] In the actuator 50 of the present embodiment described above, the axial length of the medium diameter portion 36B of the shaft 36 can be set shorter than in the previously described actuator 10. As a result, in the actuator 50 of the present embodiment described above, it is possible to reduce the size of the actuator 50 in the axial direction compared to the previously described actuator 10.

[0030] (Fourth embodiment) Next, an actuator 52 according to a fourth embodiment will be described with reference to Fig. 5. Note that, in the actuator 52 according to the fourth embodiment, members and parts corresponding to those of the actuator 10 described above are denoted by the same reference numerals as those of the actuator 10 described above, and descriptions thereof may be omitted.

[0031] 5, in the actuator 52 of this embodiment, a portion of the shaft 36 of the actuator 10 described above corresponding to the large diameter portion 36A is a small diameter portion 36C. A rotor core 54 is fixed to this small diameter portion 36C by press fitting or the like. A magnet 38 is fixed to the outer circumferential surface of the rotor core 54. The fork 20 is disposed on the radial outer periphery of the medium diameter portion 36B of the shaft 36.

[0032] The actuator 52 of the present embodiment described above has a configuration including a rotor core 54. In this configuration, the actuator 52 can be designed to use the rotor core 54 of another motor.

[0033] In the actuators 10, 48, 50, and 52 of the above-described embodiments, the fork 20 is moved in the axial direction by the linear motion unit 18, but the present disclosure is not limited to this. For example, a configuration may be used in which a member other than the fork 20 is moved in the axial direction by the linear motion unit 18. Also, a configuration may be used in which the linear motion unit 18 directly engages with the controlled object.

[0034] While one embodiment of the present disclosure has been described above, the present disclosure is not limited to the above, and it goes without saying that the present disclosure can be implemented in various other modified forms without departing from the spirit and scope of the present disclosure.

[0035] <Additional Notes> (Appendix 1) A stator (12) formed in an annular shape to generate a rotating magnetic field; a shaft (36) formed of a soft magnetic material, arranged radially inwardly of the stator, and provided with a magnet (38), the shaft (36) rotating when the stator generates a rotating magnetic field; an axial displacement portion (18) provided at the rotation center of the shaft and displaced in the axial direction as the shaft rotates; An actuator (10, 48, 50, 52) having (Appendix 2) A transmission portion (20) connected to the axial displacement portion is provided on the radially outer side of the shaft, 2. The actuator according to claim 1, wherein the transmission portion is displaced in the axial direction as a result of the axial displacement portion being displaced in the axial direction. (Appendix 3) The transmission portion is provided along an outer circumferential surface of the shaft, 3. The actuator according to claim 2, wherein the axial displacement portion is displaced in the axial direction, thereby displacing the transmission portion along the outer peripheral surface of the shaft. (Appendix 4) the transmission portion is provided radially outward of the stator and along an outer circumferential surface of a housing (14) that supports the stator, 3. The actuator according to claim 2, wherein the axial displacement portion is displaced in the axial direction, thereby displacing the transmission portion along the outer peripheral surface of the housing. [Explanation of symbols]

[0036] 10 actuator, 12 stator, 14 housing, 18 axial displacement section, 20 transmission section, 36 shaft, 38 magnet, 48 actuator, 50 actuator, 52 actuator

Claims

1. a stator (12) formed in an annular shape to generate a rotating magnetic field; a shaft (36) formed of a soft magnetic material, arranged radially inward relative to the stator, and provided with a magnet (38), the shaft rotating when the stator generates a rotating magnetic field; an axial displacement portion (18) provided at the rotation center of the shaft and displaced in the axial direction as the shaft rotates; Equipped with A transmission part (20) connected to the axial displacement part is provided on the radially outer side of the shaft along the outer circumferential surface of the shaft, An actuator (10, 48, 52) in which the axial displacement portion displaces in the axial direction, thereby displacing the transmission portion in the axial direction along the outer circumferential surface of the shaft.

2. A stator (12) formed in an annular shape and generating a rotating magnetic field; a shaft (36) formed of a soft magnetic material, arranged radially inward relative to the stator, and provided with a magnet (38), the shaft rotating when the stator generates a rotating magnetic field; an axial displacement portion (18) provided at the rotation center of the shaft and displaced in the axial direction as the shaft rotates; Equipped with A transmission portion (20) connected to the axial displacement portion is disposed radially outward of the shaft and is provided along an outer peripheral surface of a housing (14) that supports the stator, An actuator (50) in which the axial displacement portion displaces in the axial direction, causing the inner peripheral surface of the transmission portion to slide against the outer peripheral surface of the housing, and the transmission portion to displace in the axial direction along the outer peripheral surface of the housing.

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