JP2016102515A - Rotary actuator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rotary actuator capable of suppressing abrasion and breakage of accommodated components in a case.SOLUTION: A rotary actuator includes a wave washer 89. The wave washer 89 generates energizing force to bring an output member axially movable integrally with a motor shaft 44, into contact with an inner wall of a second case. Thus thrust backlash between an axial moving body composed of the motor shaft 44, and members (a rotor 41, a bearing 48, a planetary gear and an output member) axially movable integrally with the motor shaft 44, and a first case 21 and the second case can be prevented, and the axial moving body can be prevented from being axially swung by vibration and the like added from the external when a motor 30 is in a non-energized state. Thus application of stress to the accommodated components in the case caused by axial swinging of the axial moving body can be suppressed.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a rotary actuator.

Conventionally, for example, a rotary actuator used in a drive unit of a shift-by-wire system of a vehicle is known. The rotary actuator disclosed in Patent Document 1 includes a motor, a speed reduction mechanism that decelerates the rotation of the motor, an output member that outputs the decelerated rotation to the outside, and a case that houses the motor and the speed reduction mechanism. I have.
The case includes a bottomed cylindrical first case that supports one end of the motor and a bottomed cylindrical second case that supports the other end of the motor. The first case and the second case are combined and fixed with respect to the stored article from both sides in the axial direction.

JP 2009-177982 A

  By the way, in patent document 1, the rotor and motor shaft of a motor are movable to an axial direction integrally with the bearing attached to the motor shaft, the planetary gear which comprises a reduction mechanism, and an output member. A thrust backlash always exists between the axially movable body such as the rotor and the first case and the second case due to the influence of tolerances and the like. For this reason, stress is applied to the housing part due to the axial moving body being shaken in the axial direction by vibration applied from the outside when the motor is in a non-energized state, and the housing part is worn or damaged. There is a risk.

On the other hand, a measure to reduce thrust backlash by inserting a shim plate between the axially movable body and the case can be considered. However, even with this measure, the thrust backlash cannot be completely eliminated, and the housing parts may still be worn and damaged.
The present invention has been made in view of the above-described points, and an object of the present invention is to provide a rotary actuator that can suppress wear and breakage of a housing component in a case.

  The rotary actuator according to the present invention includes biasing means. The urging means includes a motor shaft or a member that is movable in the axial direction integrally with the motor shaft, a member fixed to the first case or the first case, or a second case or the second case. An urging force that abuts against the member is generated.

  This configuration eliminates the thrust backlash between the first moving case and the second moving case, which is an axial moving body made up of a motor shaft and a member that can move in the axial direction integrally with the motor shaft. It is possible to avoid the axially movable body from being shaken in the axial direction due to vibrations or the like applied from the outside in the energized state. Therefore, it is possible to suppress the stress from acting on the housing component due to the axial direction moving body being shaken in the axial direction. Therefore, according to the present invention, it is possible to suppress wear and breakage of the housing component.

It is sectional drawing of the rotary actuator by one Embodiment of this invention. It is the II-II sectional view taken on the line of the rotary actuator of FIG. It is an enlarged view of the solenoid of FIG. 1, Comprising: It is a figure which shows the non-energized state of a solenoid coil. It is an enlarged view of the solenoid of FIG. 1, Comprising: It is a figure which shows the electricity supply state of a solenoid coil. FIG. 2 is a schematic diagram of the rotary actuator of FIG. 1 and shows a non-energized state of a solenoid coil. FIG. 2 is a schematic diagram of the rotary actuator of FIG. 1, showing a state of energization of a solenoid coil.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[One Embodiment]
A rotary actuator according to an embodiment of the present invention is shown in FIG. The rotary actuator 10 is used, for example, as a drive unit of a vehicle shift-by-wire system.

(overall structure)
First, the overall configuration of the rotary actuator 10 will be described with reference to FIGS. 1 and 2.
The rotary actuator 10 includes a case 20, a motor 30, a speed reduction mechanism 50, and an output member 60.

  The case 20 includes a cup-shaped first case 21 and a second case 22. The first case 21 and the second case 22 are combined with each other from both sides in the axial direction and fixed with bolts 24. A cup-shaped metal plate 23 is embedded in the first case 21.

The motor 30 is a switched reluctance motor and includes a stator 31, a rotor 41, and a motor shaft 44.
The stator 31 has a stator core 32 and a plurality of coils 37. The stator core 32 forms a cylindrical back yoke 33 and a plurality of teeth 34 projecting radially inward from the back yoke 33 and around which coils 37 are wound. One end portion 35 of the back yoke 33 is press-fitted inside the metal plate 23, and the other end portion 36 is fitted to the second case 22. In the present embodiment, the stator core 32 is made by laminating a plurality of metal plates in the axial direction.

  The rotor 41 is rotatably provided inside the stator 31, and includes a cylindrical boss 42 and a plurality of salient poles 43 protruding radially from the boss 42. In the present embodiment, the rotor 41 is made by laminating a plurality of metal plates in the axial direction.

  The motor shaft 44 is press-fitted inside the rotor 41 and can rotate integrally with the rotor 41. One end portion 45 of the motor shaft 44 is rotatably supported by the first case 21 via a bearing 48, and the other end portion 46 of the motor shaft 44 is rotatable by an output member 60 via a bearing 49. It is supported by. The motor shaft 44 forms an eccentric portion 47 that is eccentric with respect to the one end portion 45 and the other end portion 46 between the one end portion 45 and the other end portion 46.

  The reduction mechanism 50 is a kind of planetary gear device, and includes a ring gear 51 and a planetary gear 52. The ring gear 51 is provided coaxially with the axial center AX1 of the one end 45 and the other end 46 and is fixed to the second case 22. The planetary gear 52 is coaxially provided with the eccentric shaft center AX2 that is the shaft center of the eccentric portion 47, meshes with the ring gear 51 so as to be inscribed therein, and is supported by the eccentric portion 47 via the bearing 54 so as to be capable of planetary motion. Yes. The planetary motion is a motion that revolves around the axis AX1 while rotating around the eccentric axis AX2. The rotation speed of the planetary gear 52 during planetary movement is changed with respect to the rotation speed of the motor shaft 44. The planetary gear 52 forms a rotation transmission protrusion 53 protruding in the axial direction.

  The output member 60 is provided coaxially with the shaft center AX1, is rotatably supported by the second case 22 via a bearing 61, and has a through hole 62 into which the protrusion 53 is inserted. The rotation of the planetary gear 52 is transmitted to the output member 60 through an engaging portion between the projection 53 and the inner wall of the through hole 62.

  In the rotary actuator 10 configured as described above, when the coil 37 is energized sequentially for each phase, a rotating magnetic field is generated, and the rotor 41 receives the magnetic attractive force or repulsive force generated by the rotating magnetic field. Rotate. When the motor shaft 44 rotates about the axis AX1 together with the rotor 41, the planetary gear 52 performs planetary motion, and the rotation of the planetary gear 52 decelerated with respect to the rotation of the motor shaft 44 is output from the output member 60 to the outside.

(Feature configuration)
Next, a characteristic configuration of the rotary actuator 10 will be described with reference to FIGS.
As shown in FIG. 1, the rotary actuator 10 includes a solenoid 70 outside the first case 21 and on the opposite side of the motor 30 from the speed reduction mechanism 50. Hereinafter, the motor 30 side with respect to the solenoid 70 is described as “one axial direction”, and the solenoid 70 side with respect to the motor 30 is described as “the other axial direction”.

As shown in FIG. 3, the solenoid 70 includes a solenoid coil 71, a bobbin 72, a stator core 73, a yoke 74, a housing 79, a mover 86, and a wave washer 89.
The solenoid coil 71 is an annular coil made of a conductive wire wound around a cylindrical bobbin 72.
The stator core 73 is a disk-shaped member made of a magnetic material, and is provided on the other side in the axial direction with respect to the solenoid coil 71.

  The yoke 74 is a cylindrical member made of a magnetic material, and is connected to the outer cylindrical portion 75 provided outside the solenoid coil 71 and the outer cylindrical portion 75 on one side in the axial direction with respect to the solenoid coil 71. A bottom portion 76 and an inner cylindrical portion 77 protruding from the bottom portion 76 toward the stator core 73 inside the solenoid coil 71. The outer cylinder part 75 is in contact with the stator core 73. The inner cylinder part 77 is provided with a predetermined gap 78 between the stator core 73 and the inner cylinder part 77.

  The housing 79 is attached to the first case 21 by a body portion 81 in which a yoke 74 and a stator core 73 are molded, a connector portion 83 that fixes a terminal 82 for energizing the solenoid coil 71, and a bolt 84. And a fastening portion 85 that is fastened.

  The mover 86 can reciprocate in the axial direction inside the yoke 74, and has a plunger 87 and a mover core 88. The plunger 87 is provided coaxially with the motor shaft 44 on the other axial side with respect to the motor shaft 44, and can press the motor shaft 44 in the axial direction when moving in one axial direction. The mover core 88 is a cylindrical member made of a magnetic material, and is fixed to the outside of the plunger 87. When the solenoid coil 71 is energized, the mover core 88 is disposed on the other side in the axial direction so as to magnetically bypass between the inner cylindrical portion 77 of the yoke 74 and the stator core 73 as shown in FIG. Moving. That is, when energized, the solenoid coil 71 generates a magnetic force that moves the mover 86 to the other side in the axial direction.

  The wave washer 89 is an elastic member provided between the stator core 73 and the mover core 88, and urges the mover 86 in one axial direction. As shown in FIG. 3, the wave washer 89 urges the motor shaft 44 in one axial direction via the mover 86 when the solenoid coil 71 is not energized. As shown in FIG. 5, the urging force at this time is such that the output member 60, which is a member that can move in the axial direction integrally with the motor shaft 44 together with the rotor 41, the bearings 48, 49, 54, and the planetary gear 52, It is set so as to be able to contact the flange portion 63 of the bearing 61 which is a member fixed to the case 22.

  On the other hand, as shown in FIGS. 4 and 6, when the mover 86 is moved to the other axial direction by energization of the solenoid coil 71, the urging of the motor shaft 44 by the wave washer 89 is released. The magnetic force generated by energization of the solenoid 70 is set so that the mover 86 can be moved in the other axial direction against the urging force of the wave washer 89. The wave washer 89 corresponds to “biasing means” recited in the claims.

(effect)
As described above, in the present embodiment, the rotary actuator 10 includes the wave washer 89. The wave washer 89 generates a biasing force that abuts the output member 60 that is movable in the axial direction integrally with the motor shaft 44 against the flange portion 63 of the bearing 61 fixed to the second case 22.

  With such a configuration, the axially movable body including the motor shaft 44 and members (rotor 41, bearings 48, 49, 54, planetary gear 52, and output member 60) that can move integrally with the motor shaft 44 in the axial direction. And the thrust backlash between the first case 21 and the second case 22 is eliminated, and the axially moving body is prevented from being shaken in the axial direction due to vibration applied from the outside when the motor 30 is in a non-energized state. Can do. Therefore, it is possible to suppress the stress from acting on the housing components in the cases 21 and 22 due to the axially moving body being shaken in the axial direction. Therefore, according to the present embodiment, it is possible to suppress wear and breakage of the housing components in the cases 21 and 22.

In the present embodiment, the axially movable body is urged by the wave washer 89 that is an elastic member.
Therefore, the axially movable body can be urged in one axial direction without consuming electric power.

  In this embodiment, the rotary actuator 10 includes a solenoid 70 including a mover 86 and a solenoid coil 71. The mover 86 can reciprocate in the axial direction, and can press the motor shaft 44 in the axial direction when moving in one axial direction. The solenoid coil 71 is provided outside the mover 86 and generates a magnetic force that moves the mover 86 to the other side in the axial direction when energized. The wave washer 89 urges the motor shaft 44 in the axial direction via the mover 86 when the solenoid coil 71 is not energized, while releasing the urging of the motor shaft 44 when the solenoid coil 71 is energized. It is done.

  Thus, when driving the motor 30, the urging of the motor shaft 44 by the wave washer 89 is released so that the pressing of the output member 60 against the flange portion 63 does not become a rotational resistance when the motor 30 is driven. Can do.

Further, in the present embodiment, the rotary actuator 10 is used as a drive unit of a vehicle shift-by-wire system.
The shift-by-wire system operates only when the shift range of the vehicle transmission is switched, and the drive time zone of the motor 30 is overwhelmingly smaller than the non-drive time zone. Therefore, the power consumption of the solenoid 70 can be suppressed as much as possible by setting the time zone for energizing the solenoid 70 to be the same as the drive time zone of the motor 30.

[Other Embodiments]
In another embodiment of the present invention, the biasing means may be another spring such as a disc spring or a coil spring, or may be another elastic member such as rubber. Further, the urging means is not limited to an elastic member, and may be constituted by an electric drive unit.
In another embodiment of the present invention, the means for releasing the urging of the motor shaft by the urging means when the motor is operated is not limited to a solenoid, but an electric drive unit such as a motor or a hydraulic drive such as a hydraulic cylinder Other types of driving units such as a unit may be used.

In another embodiment of the present invention, the urging force of the urging means may be transmitted directly to the motor shaft without going through the solenoid mover. Further, the urging force of the urging means is not only transmitted to the motor shaft via a member (movable element) that linearly moves in the axial direction, but is also transmitted to the motor shaft via, for example, an insulator or a rotating body. May be.
In another embodiment of the present invention, the biasing means includes a first case, a member fixed to the first case, or a second case, the motor shaft or a member that is movable in the axial direction integrally with the motor shaft. You may make it contact | abut.

In another embodiment of the present invention, the motor is not limited to a switched reluctance motor, and may be another type of synchronous motor or the like.
In other embodiments of the present invention, the speed reduction mechanism may be another type of planetary gear unit, or may be of another type, such as a spur gear speed reduction mechanism.
In other embodiments of the present invention, the rotary actuator may be used in devices other than a vehicle shift-by-wire system.
The present invention is not limited to the embodiments described above, and can be implemented in various forms without departing from the spirit of the invention.

DESCRIPTION OF SYMBOLS 10 ... Rotary actuator 21 ... 1st case 22 ... 2nd case 31 ... Stator 41 ... Rotor 44 ... Motor shaft 50 ... Deceleration mechanism 60 ... Output member 89 ... Wave washers (biasing means)

Claims (4)

A stator (31);
A rotor (41) rotatable inside the stator;
A motor shaft (44) rotatable integrally with the rotor;
A speed reduction mechanism (50) for reducing the rotation of the motor shaft;
An output member (60) capable of outputting the rotation decelerated by the deceleration mechanism to the outside;
A first case (21) rotatably supporting one end of the motor shaft;
A second case (22) that rotatably supports the other end of the motor shaft, and that defines an accommodation space for accommodating the stator, the rotor, and the speed reduction mechanism between the first case and the second case (22).
The motor shaft or a member movable in the axial direction integrally with the motor shaft, the member fixed to the first case or the first case, or the member fixed to the second case or the second case Urging means (89) generating a urging force to abut against (63);
A rotary actuator (10) comprising:   The rotary actuator according to claim 1, wherein the biasing means is an elastic member. A mover (86) capable of reciprocating in the axial direction and capable of pressing the motor shaft in the axial direction when moving in one axial direction;
A solenoid coil (71) that generates a magnetic force to move the mover to the other in the axial direction when energized;
Further comprising
The urging means urges the motor shaft to one axial direction via the mover when the solenoid coil is not energized, while the urging force of the motor shaft is released when the solenoid coil is energized. The rotary actuator according to claim 1 or 2, characterized in that   The rotary actuator according to claim 3, wherein the rotary actuator is used as a drive unit of a vehicle shift-by-wire system.

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