JP2009240030A - Actuator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inexpensive actuator wherein the number of parts are reduced to enhance integration property and the transfer of rotation is continued or discontinued according to transferred torque and an actuator that makes it possible to further enhance safety. <P>SOLUTION: The actuator includes: an electric motor; and a speed reducing mechanism that decelerates the rotation of the electric motor and transfers it to an output shaft 50. A torque limiter 60 for continuing or discontinuing the transfer of rotation is provided between the speed reducing mechanism and the output shaft 50. The torque limiter 60 includes: a limit cover 62 that is input with the rotation of the electric motor; a limit plate 63 that is provided so that it is rotated relative to the limit cover 62 and outputs the rotation of the electric motor to the output shaft 50; and a facing member 64 that is provided between the limit cover 62 and the limit plate 63 and biases the limit cover 62 and the limit plate 63 with predetermined frictional force. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an actuator used in a drive switching device that performs switching between two-wheel drive and four-wheel drive of an automobile, or switching between a neutral position and a drive position, for example.

2. Description of the Related Art Conventionally, there is known a drive switching device in which an actuator that strokes a shift fork by driving an electric motor is provided in a transfer of a four-wheel drive vehicle, and a two-wheel / four-wheel drive state is switched by a switch operation from the room.
The actuator includes a worm reducer that is a reduction mechanism, and this worm reducer is linked to the rotating shaft of the electric motor. A rack and pinion pinion is connected to the worm wheel of the worm reducer.

A rack engaged with the pinion is connected to a fork shaft for making the shift fork stroke. That is, the rotational movement of the electric motor is converted into a reciprocating movement through a reduction mechanism composed of a worm reduction gear and a rack and pinion, and the shift fork is stroked by the fork shaft.
When the shift fork strokes, a sleeve or dog clutch having spline teeth provided on the drive train is displaced. Then, the drive shaft and the driven shaft are connected / released, whereby the two-wheel / four-wheel drive state is switched.

  In addition, the actuator is provided with a waiting mechanism in the speed reduction mechanism. That is, a waiting mechanism is disposed between the worm reduction gear and the pinion. The waiting mechanism includes an input rotating member to which rotation of the electric motor is input, an output member that transmits power to the shift fork, and a spiral spring provided between the input rotating member and the output member, The rotation of the input rotation member is transmitted to the output member via a spiral spring. When the sleeve and the dog clutch cannot be displaced because of the phase mismatch of the spline teeth of the drive shaft and the driven shaft, and the shift fork is locked, the waiting mechanism stores a reaction force (elasticity).

That is, when the shift fork is locked and the transmission torque becomes larger than a predetermined value, the spiral spring is bent and elastically deformed to accumulate the rotational force of the electric motor as an urging force for causing the shift fork to stroke. ing. Therefore, when the sleeve or dog clutch becomes displaceable again, the shift fork can be stroked by the restoring force of the spiral spring without excessive thrust acting on the shift fork, and the drive shaft and the driven shaft are connected / released. Can be performed smoothly (see, for example, Patent Document 1).
JP 2006-38091 A

However, in the above-described conventional technology, there is a problem that not only the number of parts is increased but the assemblability is poor because the spiral spring is elastically deformed when the shift fork is locked.
Further, the load applied to the spiral spring constituting the waiting mechanism is increased. That is, it is necessary to set the spring constant of the spiral spring to a size that allows the shift fork to stroke. For this reason, the spiral spring becomes larger, and accordingly, the electric motor also requires more torque than necessary. As a result, there exists a subject that the whole actuator will enlarge.
Furthermore, if the structure is such that when the shift fork is locked, the spiral spring is elastically deformed to absorb the phase mismatch between the spline teeth of the drive shaft and the driven shaft, there is a limit in the allowable time for the mismatch, and the actuator and the two-wheel / 4 There exists a subject that the drive switching apparatus which switches a wheel drive state may be damaged.

Therefore, the present invention has been made in view of the above-described circumstances, and can reduce the number of parts and improve the assemblability, and can inexpensively interrupt rotation transmission according to transmission torque. An actuator is provided.
The present invention also provides an actuator that can further enhance safety.

  In order to solve the above-described problem, the invention described in claim 1 is an actuator including an electric motor and a speed reduction mechanism that reduces the rotation of the electric motor and transmits the rotation to the output shaft. A torque limiter for intermittently transmitting rotation to the output shaft is provided. The torque limiter is connected to the speed reduction mechanism and receives rotation of the electric motor, and is coaxial with the drive rotor. Provided to be relatively rotatable with respect to the drive rotator, and is provided between a driven rotator that outputs the rotation of the electric motor to the output shaft, and between the drive rotator and the driven rotator, These drive rotators and a friction member that urges a predetermined friction force on the driven rotator, and a transmission torque between the drive rotator and the driven rotator is less than or equal to the predetermined friction force In case While the rotation of the dynamic rotator is transmitted to the driven rotator, and the transmission torque between the drive rotator and the driven rotator is greater than the predetermined frictional force, the rotation of the drive rotator is rotated. Is prevented from being transmitted to the driven rotating body.

  The invention described in claim 2 is characterized in that a gear that meshes with a reduction gear of the reduction mechanism is formed integrally with the driving rotating body.

  According to the present invention, when the transmission torque between the drive rotator and the driven rotator is a predetermined value or less without using a spiral spring as in the conventional waiting mechanism, the rotation of the drive rotator is driven. It can be transmitted to the rotating body. Further, when the transmission torque between the drive rotator and the driven rotator is larger than a predetermined value, it is possible to prevent the rotation of the drive rotator from being transmitted to the driven rotator. For this reason, not only can the number of components be reduced to improve assemblability, but also the manufacturing cost can be reduced.

  Further, for example, when the shift fork is locked, the driven rotor is locked as compared with the conventional structure in which the spiral spring is elastically deformed to absorb the phase mismatch between the spline teeth of the drive shaft and the driven shaft. Even in this case, the drive rotator can continue to rotate. For this reason, it is possible to reliably prevent damage to the device even when the mismatch time becomes long, and to provide a highly safe actuator.

Next, embodiments of the present invention will be described with reference to the drawings.
As shown in FIG. 1, the actuator 1 is used, for example, for a drive switching device that switches the driving of a four-wheel vehicle between a two-wheel drive and a four-wheel drive, and includes an electric motor 3 and a speed reduction mechanism in a casing 2. 4. A clutch mechanism 5 for connecting the electric motor 3 and the speed reduction mechanism 4 and a torque limiter 60 linked to the speed reduction mechanism 4 are provided.
The casing 2 includes an electric motor storage unit 6 that stores the electric motor 3 and a speed reduction mechanism storage unit 7 that stores the speed reduction mechanism 4. Seven bolt holes 8 are provided on the outer peripheral edge of the casing 2 so as to be used when the actuator 1 is fixed.

The electric motor 3 is a so-called DC brush motor in which an armature 10 is rotatably disposed in a bottomed cylindrical yoke 9. A tile-shaped permanent magnet 11 divided in the circumferential direction is fixed to the inner peripheral surface of the yoke 9 at equal intervals, and adjacent magnetic poles are opposite to each other.
The armature 10 includes an armature core 13 fixed to the rotating shaft 12, an armature coil 14 wound around the armature core 13, and a commutator 15 provided adjacent to the armature core 13.

The rotary shaft 12 is formed such that the shaft diameter becomes narrower due to a step as it goes toward the tip of the clutch mechanism 5 side. That is, the rotary shaft 12 includes a shaft main body 12a to which the armature core 13 is externally fitted and fixed, a first reduced diameter portion 16a having a diameter reduced by a level difference from the shaft main body 12a, and a first reduced diameter portion 16a. The second reduced diameter portion 16b reduced in diameter by the step is integrally formed in this order, and the bearing portion 16c reduced in diameter by the step is also integrally formed on the base end side (right side in FIG. 1) of the shaft body 12a. ing.
The second reduced diameter portion 16b is flattened at one place. The bearing portion 16 c of the rotating shaft 12 is rotatably supported by a bearing 18 that is press-fitted and fixed to a boss 17 that is formed to protrude from an end portion 9 a (bottom portion) of the yoke 9.

The armature core 13 is obtained by laminating a plurality of ring-shaped metal plates in the axial direction. Teeth 19 having a substantially T shape in plan view are radially formed at equal intervals along the circumferential direction on the outer peripheral portion of the metal plate. By fixing a plurality of metal plates to the shaft main body 12 a of the rotating shaft 12, dovetail-shaped slots 20 are formed between the adjacent teeth 19 on the outer periphery of the armature core 13. The slots 20 extend along the axial direction and are formed at equal intervals along the circumferential direction.
An enamel-coated winding 21 is wound around the teeth 19 through the slot 20. As a result, a plurality of armature coils 14 are formed on the outer periphery of the armature core 13.

  The commutator 15 is externally fitted and fixed to the first reduced diameter portion 16 a of the rotary shaft 12. The commutator 15 performs so-called rectification that switches the direction of the current flowing through the armature coil 14, and a segment 22 made of a conductive material is attached to the outer peripheral surface of the commutator 15.

  The segments 22 are made of plate-shaped metal pieces that are long in the axial direction, and are fixed in parallel at equal intervals along the circumferential direction in a state of being insulated from each other. A riser 23 is integrally formed at the end of each segment 22 on the side of the armature core 13 so as to be folded back to the outer diameter side. The riser 23 has a winding start end and a winding end end. A winding 21 is wound around. The coil | winding 21 is being fixed to the riser by the fusing, and, thereby, the segment 22 and the armature coil 14 corresponding to this are electrically connected.

A bottomed cylindrical cover 24 is fastened and fixed to the open end of the yoke 9 by bolts 25a and nuts 25b. A holder stay (not shown) is attached to the inside of the cover 24, and a brush (not shown) slidably contacting the commutator 15 is provided here.
A common bearing 26 is provided at the end 24a (bottom) of the cover 24 at the center in the radial direction. The common bearing 26 is a sliding bearing for rotatably supporting the first reduced diameter portion 16 a of the rotating shaft 12 and one end of the clutch mechanism 5, and includes a cylindrical bearing body 27 and the bearing body 27. It is comprised with the flange part 28 integrally molded by the clutch mechanism 5 side end.

The clutch mechanism 5 transmits the rotational force of the rotary shaft 12 based on the drive of the electric motor 3 to the speed reduction mechanism 4, while the rotational force due to external force acts on the rotary shaft 12 via the speed reduction mechanism 4, thereby This is a so-called two-way clutch that prevents 12 from rotating in the reverse direction.
Here, the two-way clutch refers to a one-way clutch that transmits a driving force in only one direction (forward rotation or reverse rotation), whereas a single clutch performs both directions (forward / reverse rotation). It is possible to transmit the driving force to. That is, the clutch mechanism 5 transmits both the forward / reverse rotational force of the rotating shaft 12 to the speed reducing mechanism 4, while the rotational force from the speed reducing mechanism 4 is transmitted to the rotating shaft 12 in both forward / reverse directions. Not to be.

  Such a clutch mechanism 5 includes a cylindrical housing 29 fitted in a bottomed cylindrical casing 51, and a driving side that is connected to the rotary shaft 12 inside the housing 29 and arranged on one end side of the clutch mechanism 5. A rotating body 31, and a driven-side rotating body 32 that is connected to the driving-side rotating body 31 so as not to be rotatable relative to the driving-side rotating body and to be movable in the axial direction. A bottomed cylindrical hub rotating body 30 is interposed between the housing 29 and the housing 29.

At the end of the housing 29 on the side of the electric motor 3, an enlarged diameter portion 29 a having an enlarged diameter is formed on the inner peripheral surface so that the flange portion 28 of the common bearing 26 can be received therein.
The drive-side rotator 31 is formed in a substantially cylindrical shape, and a connection hole 33 corresponding to the second reduced diameter portion 16b of the rotary shaft 12 is formed on the electric motor 3 side. As a result, the drive-side rotator 31 and the rotary shaft 12 are not rotatable relative to each other and are movable in the axial direction.

  In addition, a diameter-reduced portion 34 having a diameter reduced by a step is formed on the outer peripheral surface at the end of the drive-side rotating body 31 on the electric motor 3 side, and the shared bearing 26 rotatably supports this portion. Yes. That is, the outer diameter E1 of the reduced diameter portion 34 of the drive-side rotator 31 is set so as to substantially match the outer diameter E2 of the first reduced diameter portion 16a of the rotating shaft 12.

  Furthermore, a driven-side rotator 32 is externally fitted to a reduced diameter portion 35 formed by a step at the opposite end of the drive-side rotator 31 from the electric motor 3. The reduced-diameter portion 35 of the drive-side rotator 31 is flattened at one location, while the connection hole 36 of the driven-side rotator 32 that receives the reduced-diameter portion 35 is formed so as to correspond to the reduced-diameter portion 35. Has been. Thereby, both 31 and 32 cannot be rotated relative to each other and are movable in the axial direction.

The drive-side rotator 31 and the driven-side rotator 32 are accommodated in a bottomed cylindrical hub rotator 30 in a state of being overlapped with each other. That is, the hub rotating body 30 is interposed between the drive side rotating body 31 and the driven side rotating body 32 and the housing 29.
The hub rotating body 30 is provided so that the opening is on the electric motor 3 side. A coil spring 52 is provided between the hub rotating body 30 and the housing 29. The coil spring 52 is deformed to be radially reduced toward the inner side in the radial direction or expanded toward the outer side in the radial direction in accordance with the rotational driving of the driving side rotating body 31 and the driven side rotating body 32. It has become.

That is, in the clutch mechanism 5, when the drive-side rotator 31 is driven, the drive-side rotator 31 is driven to reduce the diameter of the coil spring 52. The driven side rotator 32 is integrated so that both rotate together. For this reason, the rotational force is transmitted from the driving side rotating body 31 to the driven side rotating body 32.
On the other hand, when the hub rotating body 30 is driven before the driving side rotating body 31, the driven side rotating body 32 is driven to cause the coil spring 52 to be enlarged and deformed. Friction resistance is generated during As a result, the rotation of the driven-side rotator 32 is restricted, and transmission of the rotational force from the hub rotator 30 to the drive-side rotator 31 is prevented.

  A boss portion 37 protruding outward in the axial direction is formed on the end portion 30a (bottom portion) of the hub rotating body 30, and a first pinion 38 constituting the speed reduction mechanism 4 is press-fitted and fixed thereto. The speed reduction mechanism 4 includes a first pinion 38, a second pinion 43, a first spur gear 42, a second spur gear 44, and a worm shaft 45.

  The first pinion 38 is formed in a cylindrical shape, and is formed by integrally forming a connecting portion 40 formed on the proximal end side and connected to the clutch mechanism 5 and a tooth portion 41 formed on the distal end side. Yes. The connecting portion 40 of the first pinion 38 is rotatably supported by a bearing 39 provided at the end of the housing 29 opposite to the electric motor 3. That is, the hub rotating body 30 press-fitted into the connecting portion 40 of the first pinion 38 is in a state of being rotatably supported by the bearing 39 via the first pinion 38.

Here, the pitch circle diameter PC of the tooth portion 41 is set smaller than the diameter of the connecting portion 40.
By doing in this way, the drive moment which acts on the 1st pinion 38 can be made small compared with the case where the pitch circle diameter PC of the tooth | gear part 41 is set larger than the diameter of the connection part 40. FIG. For this reason, it becomes possible to provide the bearing 39 only in the connection part 40 of the 1st pinion 38, ie, to support the 1st pinion 38 by cantilever.

  A first spur gear 42 is meshed with the tooth portion 41 of the first pinion 38. The first spur gear 42 is integrally formed with a second pinion 43 extending toward the electric motor 3, and the first spur gear 42 and the second pinion 43 are formed by the cover 24 of the casing 2 and the electric motor 3. And is supported rotatably.

  A second spur gear 44 is engaged with the second pinion 43. A worm shaft 45 extending toward the electric motor 3 is integrally formed with the second spur gear 44. The worm shaft 45 is accommodated in a worm accommodating portion 48 provided in the casing 2, and is rotatably supported by bearings 49, 49 provided in the worm accommodating portion 48. The worm shaft 45 is provided so that the axis P1 is along the axis P2 of the electric motor 3. A torque limiter 60 is linked to the worm shaft 45.

  As shown in FIG. 2, the torque limiter 60 includes a substantially disc-shaped base member 61 that is pivotally supported at one end of the holding shaft 59, and a side opposite to the holding shaft 59 of the base member 61 (left side in FIG. 2). A limit cover 62 formed in a bottomed cylindrical shape so as to cover the surface, a limit plate 63 provided on the inner surface side of the limit cover 62 and connected to the output shaft 50, and between the limit cover 62 and the limit plate 63 And a facing member 64 provided.

  The other end of the holding shaft 59 is fixed to the speed reduction mechanism housing portion 7 of the casing 2. The base member 61 is formed with a boss portion 65 protruding in the axial direction from both surfaces at the center in the radial direction. A bearing hole 66 penetrating in the axial direction is formed at the center of the boss portion 65 in the radial direction, and a sliding bearing 67 is press-fitted and fixed therein. Accordingly, the base member 61 is pivotally supported by the holding shaft 59 via the slide bearing 67.

A male screw portion 68 is engraved on the outer peripheral surface of the base member 61. On the other hand, on the peripheral wall 69 of the limit cover 62, a female screw portion 70 into which a male screw portion 68 is screwed is formed on the inner peripheral surface. That is, the base member 61 is fastened and fixed to the limit cover 62 and rotates integrally with the limit cover 62.
A resin helical gear 71 that meshes with the worm shaft 45 is integrally formed on the outer peripheral surface of the peripheral wall 69 of the limit cover 62. The end portion (bottom wall) 72 of the limit cover 62 is formed with an insertion hole 74 into which a cylindrical connecting member 73 described later can be inserted. A limit plate 63 is disposed on the end portion 72 of the limit cover 62 via a substantially annular facing member 64 on the inner surface side in plan view.

The facing member 64 serves as a friction plate that urges the limit plate 63 to apply a frictional force, and is attached to the end portion 72 of the limit cover 62.
The limit plate 63 is formed in a substantially disk shape, and a connection hole 75 for connecting the connection member 73 is formed at the center in the radial direction. A connecting member 73 that protrudes outward in the axial direction through the insertion hole 74 of the limit cover 62 is fixed to the connecting hole 75. The limit plate 63 and the connecting member 73 can be molded in consideration of the required accuracy by making each of them separate and fixing them together.

  The connecting member 73 is for connecting the limit plate 63 and the output shaft 50, and a spline 76 is formed on the inner peripheral surface side. On the other hand, a spline 77 is also formed at a portion corresponding to the connecting member 73 of the output shaft 50, and both 73 and 50 are spline-fitted. As a result, the output shaft 50, the connecting member 73, and the limit plate 63 rotate together.

  Here, on the surface of the limit plate 63 on the base member 61 side (the right side in FIG. 2), a sliding member 78 having a substantially annular shape in plan view is disposed, and a plate between the sliding member 78 and the base member 61 is further provided. A spring 79 is provided. The sliding material 78 is for transmitting the pressing force of the disc spring 79 to the limit plate 63.

  That is, the limit plate 63 is urged toward the facing member 64 side by the sliding material 78 and the disc spring 79, whereby a frictional force is generated between the limit plate 63 and the facing member 64. It is designed to rotate together. Therefore, the frictional force can be varied by adjusting the screwing amount of the base member 61 into the limit cover 62. That is, the more the base member 61 is screwed into the limit cover 62, the stronger the frictional force.

  A bulging portion 80 formed to bulge toward the limit plate 63 side is provided on the surface of the sliding material 78 on the limit plate 63 side. By providing the sliding member 78 with the bulging portion 80, the sliding member 78 and the limit plate 63 are in line contact. This is to prevent the change in the contact area between the sliding member 78 and the limit plate 63 from affecting the sliding torque. Note that it is desirable to use a material that can maintain the shape of the sliding material 78 over a long period of time even when a pressing force is applied from the disc spring 79. Here, the sliding material 78 is a metal, but a resin that satisfies the above conditions may be used.

  A pinion (not shown) is press-fitted and fixed to the end of the output shaft 50 opposite to the torque limiter 60. This pinion is connected via a rack (not shown) to a fork shaft (not shown) for stroke of the shift fork. The fork shaft is provided on a drive train (not shown) for displacing a sleeve or dog clutch having spline teeth. By displacing the sleeve or dog clutch, the driving of the four-wheeled vehicle is changed to two-wheel driving and four-wheel driving. It can be switched to wheel drive.

Next, the operation of the torque limiter 60 of this embodiment will be described.
For example, when the two-wheel drive is selected by the drive switching device and the displacement of the sleeve and the dog clutch and the stroke of the shift fork are completed, the electric motor 3 is not energized.
On the other hand, when switching from 2-wheel drive to 4-wheel drive by the drive switching device, the electric motor 3 is energized and the rotating shaft 12 starts to rotate. Then, the rotational motion of the rotary shaft 12 is caused by the torque via the first pinion 38, the second pinion 43, the first spur gear 42, the second spur gear 44, and the worm shaft 45 constituting the clutch mechanism 5 and the speed reduction mechanism 4. It is transmitted to the helical gear 71 of the limiter 60. As a result, the limit cover 62 integrally formed with the helical gear 71 and the base member 61 fastened and fixed to the limit cover 62 start to rotate.

  Then, the limit plate 63 starts to rotate due to a frictional force generated between the limit plate 63 and the facing member 64. When the limit plate 63 rotates, the output shaft 50 integrated therewith starts to rotate. When the output shaft 50 rotates, the sleeve and the dog clutch start to be displaced via a pinion, a rack, and a shift fork (not shown).

  Here, when the phases of the spline teeth of the drive shaft and the driven shaft of the drive switching device coincide with each other, the shift fork continues to stroke smoothly. That is, since the transmission torque between the limit cover 62 and the limit plate 63 is equal to or less than the frictional force generated between the limit plate 63 and the facing member 64, the rotation of the limit cover 62 is transmitted to the limit plate 63. As a result, the shift fork continues to stroke and completes the displacement of the sleeve and dog clutch. Then, the drive shaft and the driven shaft of the four-wheel vehicle are connected via a sleeve and a dog clutch, and the switching to the four-wheel drive is completed.

  However, when the phases of the spline teeth of the drive shaft and the driven shaft do not match, the sleeve and the dog clutch cannot be displaced, and the shift fork is locked. At this time, the output shaft 50, the connecting member 73, and the limit plate 63 are stopped, while the limit cover 62 (helical gear 71) and the base member 61 linked to the rotating shaft 12 of the electric motor 3 rotate. to continue. That is, the transmission torque between the limit cover 62 and the limit plate 63 becomes larger than the frictional force generated between the limit plate 63 and the facing member 64. Therefore, the rotation of the limit cover 62 is not transmitted to the limit plate 63, and the limit cover 62 (helical gear 71) and the base member 61 continue to rotate.

When the phases of the spline teeth of the drive shaft and the driven shaft coincide with each other and the sleeve and the dog clutch can be displaced, the transmission torque between the limit cover 62 and the limit plate 63 is again transmitted between the limit plate 63 and the facing member 64. Therefore, the rotation of the limit cover 62 is transmitted to the limit plate 63. As a result, the shift fork strokes to complete the displacement of the sleeve and dog clutch.
The torque limiter 60 functions in the same manner as when switching from two-wheel drive to four-wheel drive when switching from four-wheel drive to two-wheel drive, and displaces the sleeve and dog clutch. The description when switching to is omitted.

Therefore, according to the above-described embodiment, when the transmission torque between the limit cover 62 and the limit plate 63 is not more than a predetermined value without using a spiral spring as in the conventional waiting mechanism, that is, the limit plate 63 and The rotation of the limit cover 62 can be transmitted to the limit plate 63 when the frictional force is less than or equal to the friction force generated between the facing member 64. Further, when the transmission torque between the limit cover 62 and the limit plate 63 is larger than a predetermined value, that is, when the frictional force generated between the limit plate 63 and the facing member 64 is large, the limit cover 62 is rotated. Transmission to the limit plate 63 can be prevented.
For this reason, when the shift fork is locked as in the prior art, the number of parts can be reduced compared to a structure in which the spiral spring is elastically deformed to absorb the phase mismatch between the spline teeth of the drive shaft and the driven shaft, The embeddability can be improved. In addition, since the structure can be simplified, the manufacturing cost can be reduced.

  Furthermore, even when the shift fork is locked due to the phase mismatch of the spline teeth of the drive shaft and the driven shaft, the limit cover 62 (helical gear 71) and the base member 61 can continue to rotate. For this reason, even if it is a case where the time of mismatch becomes long, damage to an apparatus can be prevented reliably and it becomes possible to provide actuator 1 with high safety.

The present invention is not limited to the above-described embodiment, and includes various modifications made to the above-described embodiment without departing from the spirit of the present invention.
In the above-described embodiment, the actuator 1 has been described as being used, for example, for a drive switching device that switches driving of a four-wheel vehicle between two-wheel driving and four-wheel driving. However, the present invention is not limited to this. The actuator 1 may be used in a drive switching device that switches between a neutral position and a drive position.

Furthermore, in the above-described embodiment, the case where the helical gear 71 is integrally formed with the limit cover 62 of the torque limiter 60 has been described. However, the present invention is not limited to this, and the worm shaft 45 may be meshed with a worm wheel instead of the helical gear 71.
And in the above-mentioned embodiment, the case where the facing member 64 was affixed on the end part 72 of the limit cover 62 was demonstrated. However, the present invention is not limited to this, and the limit cover 62 and the facing member 64 may be in an unbonded state by making the inner surface of the end portion 72 of the limit cover 62 rough.

Further, in the above-described embodiment, the case has been described in which the limit plate 63 and the connecting member 73 are separated from each other, and the molding that sufficiently considers the accuracy required by fixing these members to each other is possible. However, the present invention is not limited to this, and when the required accuracy of forming the limit plate 63 and the connecting member 73 is not so high, these may be integrally formed.
Furthermore, in the above-described embodiment, the case where the bulging portion 80 is provided in the sliding material 78 and the sliding material 78 and the limit plate 63 are in line contact has been described. However, the present invention is not limited to this, and the sliding member 78 may not be provided with the bulging portion 80, and the sliding member 78 and the limit plate 63 may be in surface contact.

It is sectional drawing which shows the structure of the actuator in embodiment of this invention. It is sectional drawing of the torque limiter in embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Actuator 3 Electric motor 4 Reduction mechanism 12 Rotating shaft 45 Worm shaft (reduction gear)
50 Output shaft 60 Torque limiter 61 Base member (drive rotor)
62 Limit cover (drive rotating body)
63 Limit plate (driven rotating body)
64 Facing member (friction member)
78 Sliding material 79 Disc spring

Claims (2)

An electric motor;
In an actuator comprising a reduction mechanism that reduces the rotation of the electric motor and transmits it to the output shaft,
A torque limiter for intermittently transmitting rotation is provided between the speed reduction mechanism and the output shaft,
The torque limiter is
A drive rotator linked to the speed reduction mechanism and to which rotation of the electric motor is input;
A driven rotator that is coaxial with the drive rotator and is rotatable relative to the drive rotator, and outputs the rotation of the electric motor to the output shaft;
Provided between the drive rotator and the driven rotator, the drive rotator, and a friction member for biasing a predetermined friction force to the driven rotator,
When the transmission torque between the drive rotator and the driven rotator is less than or equal to the predetermined frictional force, the rotation of the drive rotator is transmitted to the driven rotator,
When the transmission torque between the drive rotator and the driven rotator is larger than the predetermined frictional force, the rotation of the drive rotator is prevented from being transmitted to the driven rotator. An actuator characterized by comprising. The actuator according to claim 1, wherein a gear that meshes with a reduction gear of the reduction mechanism is formed integrally with the driving rotating body.

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