JP2009236175A - Actuator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an actuator reducing the size of a whole actuator by distributing a load applied to a waiting mechanism. <P>SOLUTION: The actuator is provided with an electric motor, a speed reduction mechanism for reducing rotation speed of a rotary shaft provided for the electric motor and transmitting it to an output shaft 50 and the waiting mechanism 60 provided in the speed reduction mechanism for waiting while accumulating a rotation force when the output shaft 50 is constrained until the constraint is canceled. Structured with a plurality of stages, the waiting mechanism 60 is provided with a helical gear 61 for an input plate 62 of a first stage for rotating with the input plate 62 as interlinked with the rotation shaft and an output plate 63 of the last stage is fixed in a manner incapable of relatively rotating with an output shaft 50. <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. This waiting mechanism stores the reaction force (elasticity) when the shift fork locks when the sleeve or dog clutch becomes undisplaceable due to the phase mismatch of the spline teeth of the drive shaft and the driven shaft. I have.

When the shift fork is locked, the spiral spring is bent and elastically deformed, so that the rotational force of the electric motor is accumulated as an urging force for causing the shift fork to stroke. 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, 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.

  Therefore, the present invention has been made in view of the above-described circumstances, and provides an actuator that can disperse a load applied to a waiting mechanism and reduce the size of the entire actuator.

  In order to solve the above-described problems, the invention described in claim 1 is an electric motor, a speed reduction mechanism that reduces the rotation of a rotary shaft provided in the electric motor and transmits the rotation to an output shaft, and the speed reduction mechanism. And a waiting mechanism that accumulates and waits until the restraint is released when the output shaft is restrained, and the waiting mechanism is configured to rotate from the rotating shaft. A plurality of combinations of an input plate to be input and an output plate to which rotation from the input plate is transmitted via a spring, each of the input plate, the spring, and the output plate around the output shaft. It is formed so as to surround and is arranged side by side in a multi-stage shape along the axial direction, and the first stage input plate is provided with a gear linked to the rotary shaft and rotating together with the first stage input plate, Characterized by being non-rotatably fixed to each other to the output shaft of the output plate stage after.

  According to a second aspect of the present invention, there is provided an input plate and an output plate interposed between the first stage input plate and the last stage output plate, wherein the input plate and the output are opposed to each other in the axial direction. Each of the plates is integrally formed.

  According to the present invention, the waiting mechanism can have a configuration in which a plurality of input plates and a plurality of output plates are arranged in multiple stages, and a plurality of springs interposed between each input plate and the output plate can be provided. For this reason, a load can be distributed to a plurality of springs, and the spring constant of each spring can be set small. Accordingly, the required torque of the electric motor can be set small, and as a result, the entire actuator can be reduced in size.

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, for example, a drive switching device that switches the driving of a four-wheeled 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, and the electric motor 3 and the speed reduction mechanism 4 are connected via a clutch mechanism 5.
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. The 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 formed in 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, a worm shaft 45, and a waiting mechanism 60.

  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.

The worm shaft 45 meshes with a helical gear 61 that constitutes a waiting mechanism 60.
As shown in FIGS. 2 and 3, the waiting mechanism 60 includes an output shaft 50, a substantially disk-shaped input plate 62 formed so as to surround the output shaft 50, an output plate 63, and these input It has four intermediate plates 64-67 arranged in parallel along the axial direction between the plate 62 and the output plate 63, and five coil springs 68-72 arranged between the plates 62-67. The helical gear 61 is integrally formed on the input plate 62.

  A substantially annular outer peripheral wall 62a is provided on the outer peripheral edge of the input plate 62 so as to rise toward the output plate 63, and a helical gear 61 is integrally formed therein. A substantially annular inner peripheral wall 62b is provided at the center in the radial direction of the input plate 62 so as to rise toward the output plate 63 side. The diameter of the inner peripheral wall portion 62b is set to a size that allows the output shaft 50 to be inserted.

A first coil spring 68 is accommodated in an annular recess 73 formed by the input plate 62, the outer peripheral wall portion 62a, and the inner peripheral wall portion 62b. The outer diameter of the first coil spring 68 is set to be slightly smaller than that of the outer peripheral wall portion 62a, and the first coil spring 68 exists along the inner peripheral surface of the outer peripheral wall portion 62a.
Here, hook portions 68 a that are bent toward the inner side in the radial direction are provided at both end portions of the first coil spring 68. On the other hand, the input plate 62 is provided with an engaging portion 62c having a substantially arc shape in a plan view that can engage with the hook portion 68a when the input plate 62 rotates.

  A substantially disc-shaped first intermediate plate 64 is provided at the opening of the recess 73 so as to close the opening. A substantially annular outer peripheral wall 64 a is provided on the outer peripheral edge of the first intermediate plate 64 so as to rise toward the output plate 63 side. A substantially annular inner peripheral wall 64b is provided at the center of the first intermediate plate 64 in the radial direction so as to rise toward the output plate 63 side. The diameter of the inner peripheral wall portion 64b is set to a size that allows the output shaft 50 to be inserted.

A second coil spring 69 is accommodated in an annular recess 74 formed by the first intermediate plate 64, the outer peripheral wall portion 64a, and the inner peripheral wall portion 64b. The outer diameter of the second coil spring 69 is set slightly smaller than that of the outer peripheral wall portion 64a, and the second coil spring 69 exists along the inner peripheral surface of the outer peripheral wall portion 64a.
Both end portions of the second coil spring 69 are provided with hook portions 69a that are bent toward the inside in the radial direction. On the other hand, the first intermediate plate 64 is provided with a first engagement portion 64c having a substantially arc shape in plan view that can be engaged with the hook portion 69a when the first intermediate plate 64 rotates.

Here, a second engagement portion 64d having a substantially arc shape in plan view is also provided on the input plate 62 side of the first intermediate plate 64. The second engaging portion 64d is formed so as to rise from the first intermediate plate 64 toward the input plate 62 side, is radially outward from the rotation trajectory of the engaging portion 62c of the input plate 62, and the first engaging plate 64d. The coil spring 68 is disposed on the radially inner side. When the first intermediate plate 64 rotates, it engages with the hook portion 68a of the first coil spring 68.
That is, the rotation of the input plate 62 is transmitted to the first intermediate plate 64 via the engaging portion 62 c of the input plate 62, the first coil spring 68, and the second engaging portion 64 d of the first intermediate plate 64. become.

  A substantially disc-shaped second intermediate plate 65 is provided at the opening of the concave portion 74 formed on the first intermediate plate 64 so as to close the opening. Similar to the first intermediate plate 64, the second intermediate plate 65 is provided with an outer peripheral wall portion 65 a and an inner peripheral wall portion 65 b, and the third coil spring 70 is accommodated in a recess 75 formed by these. Similar to the first coil spring 68 and the second coil spring 69, the third coil spring 70 is provided with a hook portion 70 a.

On the other hand, the second intermediate plate 65 includes a first engagement portion 65c that engages with the hook portion 70a of the third coil spring 70, and a second engagement portion 65d that engages with the hook portion 69a of the second coil spring 69. And are formed. The second engagement portion 65d is disposed on the radially outer side than the rotation locus of the first engagement portion 64c formed on the first intermediate plate 64 and on the radially inner side of the second coil spring 69. Yes.
Accordingly, the rotation of the first intermediate plate 64 is caused by the second intermediate plate 64 via the first engagement portion 64 c of the first intermediate plate 64, the second coil spring 69, and the second engagement portion 65 d of the second intermediate plate 65. 65 is transmitted.

  Similarly, a substantially disc-shaped third intermediate plate 66 for closing the recess 75 formed on the second intermediate plate 65 is provided, and the third intermediate plate 66, the outer peripheral wall 66a, In addition, a substantially disc-shaped fourth intermediate plate 67 is provided at the opening of the recess 76 formed by the inner peripheral wall portion 66b. In addition, a substantially disc-shaped output plate 63 is provided in a recess 77 formed by the fourth intermediate plate 67, the outer peripheral wall portion 67a, and the inner peripheral wall portion 67b. A fourth coil spring 71 is accommodated in the recess 76, and a fifth coil spring 72 is accommodated in the recess 77.

  Similarly to the first to third coil springs 68 to 70, hook portions 71 a and 72 a are formed on the fourth coil spring 71 and the fifth coil spring 72, respectively. Further, the third intermediate plate 66 is formed with engaging portions 66c and 66d that are engaged with the hook portion 71a of the fourth coil spring 71 and the hook portion 70a of the third coil spring 70, respectively. Are formed with engaging portions 67c and 67d that are engaged with the hook portion 72a of the fifth coil spring 72 and the hook portion 71a of the fourth coil spring 71, respectively.

  The output plate 63 is formed with an engagement portion 63 a having a substantially arc shape in plan view that engages with the hook portion 72 a of the fifth coil spring 72. Further, a fixing hole 78 in which the output shaft 50 is fitted and fixed is formed at the radial center of the output plate 63. Thereby, the output plate 63 and the output shaft 50 are integrally rotated together.

  A flange portion 53 is formed at the output plate 63 side end (left end in FIG. 2) of the output shaft 50, and the waiting mechanism 60 is positioned in the axial direction by contacting the output plate 63 here. It has become. On the other hand, the end of the output shaft 50 opposite to the output plate 63 penetrates the waiting mechanism 60 and protrudes outward, and a pinion (not shown) is press-fitted and fixed therein. 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 waiting mechanism 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 movement of the rotary shaft 12 waits through the clutch mechanism 5 and 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 speed reduction mechanism 4. It is transmitted to the helical gear 61 of the mechanism 60. As a result, the input plate 62 integrally formed with the helical gear 61 starts to rotate.

  Then, the rotation of the input plate 62 is transmitted to the first intermediate plate 64 via the engaging portion 62 c of the input plate 62, the first coil spring 68, and the second engaging portion 64 d of the first intermediate plate 64. The intermediate plate 64 rotates. When the first intermediate plate 64 is rotated, this rotation is transmitted through the first engagement portion 64 c of the first intermediate plate 64, the second coil spring 69, and the second engagement portion 65 d of the second intermediate plate 65. The second intermediate plate 65 is rotated by being transmitted to the plate 65. Subsequently, this rotation is transmitted to the output plate 63 via the engaging portions 65c, 66c, 66d, 67c, 67d, 63a and the coil springs 70, 71, 72, and the output shaft 50 rotates.

  That is, each of the intermediate plates 64 to 67 has a role of an input plate and an output plate that transmit the rotation transmitted from the input plate 62 side to the output plate 63 side. Therefore, each of the intermediate plates 64 to 67 is integrally formed with an input plate and an output plate that are opposed to each other in the axial direction. The waiting mechanism 60 is in a state in which five sets of the input plate and the output plate to which the rotation from the input plate is transmitted via the coil spring are arranged side by side in a multistage manner along the axial direction.

  More specifically, the first stage of the waiting mechanism 60 includes an input plate 62, a first coil spring 68, and a first intermediate plate 64. The second stage of the waiting mechanism 60 includes the first intermediate plate 64, the first intermediate plate 64, and the first intermediate plate 64. The third stage of the waiting mechanism 60 includes a second intermediate plate 65, a third coil spring 70, and a third intermediate plate 66. The fourth stage includes a third intermediate plate 66, a fourth coil spring 71, and a fourth intermediate plate 67. The fifth stage of the waiting mechanism 60 includes the fourth intermediate plate 67, the fifth coil spring 72, and an output. It consists of a plate 63.

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, in the case where 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 smoothly 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 and the output plate 63 are stopped, while the helical gear 61 and the input plate 62 linked to the rotating shaft 12 of the electric motor 3 continue to rotate. For this reason, each coil spring 68-72 engaged with the engaging parts 62c-67d formed in each plate 62-67 is elastically deformed, and the rotational force of the electric motor 3 is used as an urging force to stroke the shift fork. accumulate.

  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, a restoring force acts on each of the coil springs 68 to 72. Then, by this restoring force, the sleeve and the dog clutch are displaced, the drive shaft and the driven shaft are connected, and the switching to the four-wheel drive is completed. Each waiting mechanism 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, so that the sleeve and dog clutch are displaced. A description of switching to driving will be omitted.

Therefore, according to the above-described embodiment, the waiting mechanism 60 has a five-stage structure, and the five coil springs 68 to 72 are provided, thereby distributing the load when the shift fork is stroked to the coil springs 68 to 72. Can do. For this reason, while being able to set each spring constant of each coil spring 68-72 small, the required torque of the electric motor 3 can also be set small. Therefore, the entire actuator 1 can be reduced in size.
In addition, by setting the spring constants of the coil springs 68 to 72 separately, it is possible to finely set the motor torque required to stroke the shift fork for each operating angle of the output shaft 50. For this reason, it becomes possible to select the electric motor 3 more appropriately, and it is possible to reliably prevent the electric motor 3 from becoming larger than necessary.

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.

Further, in the above-described embodiment, the case where the helical gear 71 is integrally formed on the input plate 62 of the waiting mechanism 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.
In the above-described embodiment, the waiting mechanism 60 is a five-stage arrangement of an input plate and an output plate to which rotation from the input plate is transmitted via a coil spring. Explained the case. However, the present invention is not limited to this, and the waiting mechanism 60 may have at least two stages.

  Further, in the above-described embodiment, the case where each of the intermediate plates 64 to 67 is formed so that the input plate and the output plate that are opposed to each other in the axial direction are integrated with each other is described. However, the present invention is not limited to this, and the intermediate plates 64 to 67 may be divided into an input plate and an output plate, respectively.

It is sectional drawing which shows the structure of the actuator in embodiment of this invention. It is sectional drawing of the waiting mechanism in embodiment of this invention. It is sectional drawing which follows the AA line of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Actuator 3 Electric motor 4 Deceleration mechanism 12 Rotating shaft 38 1st pinion 42 1st spur gear 43 2nd pinion 44 2nd spur gear 45 Worm shaft 50 Output shaft 60 Waiting mechanism 61 Helical gear (gear)
62 Input plate 63 Output plate 64 First intermediate plate 65 Second intermediate plate 66 Third intermediate plate 67 Fourth intermediate plate 68 First coil spring (spring)
69 Second coil spring (spring)
70 Third coil spring (spring)
71 Fourth coil spring (spring)
72 Fifth coil spring (spring)

Claims (2)

An electric motor;
A speed reduction mechanism that decelerates the rotation of the rotation shaft provided in the electric motor and transmits the rotation to the output shaft;
An actuator having a waiting mechanism that is provided in the speed reduction mechanism and accumulates and waits until the output shaft is restrained until the restraint is released,
The waiting mechanism is
An input plate to which rotation from the rotating shaft is input;
Comprising a plurality of sets with an output plate in which rotation from the input plate is transmitted via a spring;
Each of the input plate, the spring, and the output plate is formed so as to surround the periphery of the output shaft, and is arranged in a multistage shape along the axial direction.
The first stage input plate is provided with a gear linked to the rotary shaft and rotating together with the first stage input plate,
An actuator characterized in that the last stage output plate is fixed to the output shaft so as not to rotate relative to each other. An input plate interposed between the first-stage input plate and the last-stage output plate, and an output plate,
2. The actuator according to claim 1, wherein an input plate and an output plate facing each other in the axial direction are integrally formed.

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