JP2009165332A - Actuator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a compact actuator by improving transmission efficiency of a worm speed reducer. <P>SOLUTION: The actuator is provided with an electric motor 3 and the worm speed reducer 47. The worm speed reducer 47 comprises a worm 45 linked with a rotating shaft 12 of the electric motor 3 and a helical gear 46 geared to the worm 45. A two-way clutch 5 is provided on the rotating shaft 12 of the electric motor 3 and the rotating shaft 12 is linked with the worm 45 via the two-way clutch 5. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an actuator including an electric motor and a worm speed reducer, and more particularly to an actuator mounted on an automobile.

  As an actuator mounted on an automobile, for example, there is an actuator used in a drive switching device that switches a transfer between a two-wheel drive state and a four-wheel drive state. The actuator for the drive switching device is connected to a worm reduction gear and an electric motor. The worm speed reducer includes a worm coupled to the rotation shaft of the electric motor and a worm wheel meshed with the worm. An output shaft is attached to the worm wheel, and a rack and pinion pinion is attached to the output shaft. The rack meshed with the pinion is supported by the casing of the actuator so as to be able to reciprocate.

The rack is provided with a shift fork. This shift fork is for driving a transfer two-wheel / four-wheel drive switching device. That is, when the rotating shaft of the electric motor is rotated, the worm wheel rotates via the worm, and the output shaft attached to the worm wheel rotates. When the output shaft rotates, the pinion rotates with it. Then, the rack meshed with the pinion moves linearly, and thereby the shift fork provided on the rack switches between the two-wheel drive state and the four-wheel drive state of the transfer (see, for example, Patent Document 1).
JP 2000-71806 A

  By the way, in the above-mentioned conventional technology, the reverse rotation of the rotating shaft of the electric motor is prevented by the self-locking of the worm speed reducer. That is, in the case of a worm speed reducer, since the worm tooth portion is formed like a screw, the meshing area between the worm and the worm wheel is increased, and the frictional force generated thereby causes the worm wheel to drive after the worm is driven. While driving the worm, it is difficult to drive the worm after driving the worm wheel.

  However, in order for the self-lock to function sufficiently, it is necessary to increase the meshing area between the worm and the worm wheel, for example, by reducing the worm lead angle. For this reason, since the transmission efficiency of the worm reducer is reduced, the worm reducer is increased in size to obtain a desired transmission efficiency, and as a result, the actuator is increased in size.

  Therefore, the present invention has been made in view of the above-described circumstances, and provides an actuator that can improve the transmission efficiency of a worm reducer and reduce the size.

In order to solve the above problems, an invention described in claim 1 includes an electric motor and a worm speed reducer, and the worm speed reducer includes a worm linked to a rotating shaft of the electric motor, and the worm. It is comprised by the meshed helical gear or worm wheel, A two-way clutch is provided in the rotating shaft of the said electric motor, The said rotating shaft and the said worm are linked | coupled via this two-way clutch.
With this configuration, it is possible to prevent reverse rotation of the rotating shaft of the electric motor with the two-way clutch, and therefore it is possible to improve the transmission efficiency by eliminating the self-lock of the worm speed reducer.

The invention described in claim 2 includes an electric motor and a worm reducer, and the worm reducer includes a worm linked to a rotation shaft of the electric motor, a helical gear or a worm wheel meshed with the worm, and A reduction mechanism comprising a plurality of gears is provided between the electric motor and the worm reducer, the rotation shaft of the electric motor and the worm are arranged in parallel, and the axis of the rotation shaft and the worm Both of them are arranged so that their axes are along the same direction.
With this configuration, the reaction force from the worm reducer is not transmitted directly to the rotating shaft of the electric motor, so compared with the case where the worm of the worm reducer and the rotating shaft of the electric motor are directly connected. Thus, the thrust force acting on the rotating shaft can be reduced.

The invention described in claim 3 includes an electric motor and a worm reducer, and the worm reducer includes a worm linked to a rotation shaft of the electric motor, a helical gear or a worm wheel meshed with the worm, and A two-way clutch is provided on the rotating shaft of the electric motor, a reduction mechanism comprising a plurality of gears is provided between the two-way clutch and the worm reducer, and the rotating shaft of the electric motor and the worm are arranged in parallel. And both are arranged such that the axis of the rotary shaft and the axis of the worm are in the same direction.
By configuring in this way, reaction force from the worm reducer is not directly transmitted to the two-way clutch, so it acts on the two-way clutch compared to the case where the worm and the two-way clutch are directly connected. It is possible to reduce the thrust force that is generated.

  According to the first aspect of the present invention, since the reverse rotation of the rotating shaft of the electric motor can be prevented by the two-way clutch, it is possible to improve the transmission efficiency by eliminating the self-locking of the worm speed reducer. For this reason, a worm reduction gear can be reduced in size and an actuator can be reduced in size.

  According to the second aspect of the present invention, the reaction force from the worm speed reducer is not directly transmitted to the rotating shaft of the electric motor, so that the worm of the worm speed reducer and the rotating shaft of the electric motor are directly connected. Compared with, it becomes possible to reduce the thrust force which acts on a rotating shaft. For this reason, it is possible to reduce the size of the bearing that rotatably supports the rotating shaft of the electric motor, and as a result, it is possible to reduce the size of the electric motor.

  According to the third aspect of the present invention, since the reaction force from the worm reducer is not directly transmitted to the two-way clutch, the two-way is compared with the case where the worm and the two-way clutch are directly connected. The thrust force acting on the clutch can be reduced. For this reason, the load on the two-way clutch can be reduced, and the service life of the two-way clutch can be extended. Therefore, the durability of the actuator can be improved.

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-wheeled vehicle between a two-wheel drive and a four-wheel drive. A mechanism 4 and a worm reduction gear 47 connected to the reduction mechanism 4 are provided, and the electric motor 3 and the reduction mechanism 4 are connected via a two-way clutch 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 rotating shaft 12 is formed such that the shaft diameter becomes narrower due to a step as it goes toward the tip of the two-way clutch 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 16a of the rotating shaft 12 and the two-way clutch 5, and includes a cylindrical bearing body 27 and a two-way clutch of the bearing body 27. It is comprised with the flange part 28 integrally formed by the 5 side end.

The two-way clutch 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 the external force acts on the rotary shaft 12 via the speed reduction mechanism 4, thereby This is to prevent 12 from being reversed.
Here, the two-way clutch 5 is a one-way clutch that transmits a driving force in only one direction (either forward rotation or reverse rotation), whereas one clutch is in both directions (forward / reverse rotation). ) Can transmit a driving force. That is, the two-way clutch 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 two-way clutch 5 includes a cylindrical housing 29 fitted in a bottomed cylindrical casing 51, a driving side rotating body 31 connected to the rotary shaft 12 inside the housing 29, and the driving side rotation. A driven-side rotating body 32 that is connected to the body 31 so as not to rotate relative to the body and is movable in the axial direction, and a bottomed cylinder between the driving-side rotating body 31 and the driven-side rotating body 32 and the housing 29. A shaped hub 30 is interposed.

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 rotating body 31 is flattened at one location, while the connection hole 36 of the driven side rotating body 32 that receives the reduced diameter portion 35 corresponds to the reduced diameter portion 35. Is formed. Thereby, both 31 and 32 cannot be rotated relatively, but can move in the axial direction.

The drive-side rotator 31 and the driven-side rotator 32 are accommodated in a bottomed cylindrical hub 30 in a state where they are overlapped with each other. That is, the hub 30 is interposed between the drive side rotating body 31 and the driven side rotating body 32 and the housing 29.
The hub 30 is provided so that the opening is on the electric motor 3 side. A coil spring 52 is provided between the hub 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 two-way clutch 5, when the drive side rotator 31 is driven first, the drive side rotator 31 is driven to reduce the diameter of the coil spring 52, which is driven by the drive side rotator 31 via the hub 30. The side rotating body 32 is integrated and 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 30 is driven before the drive-side rotator 31, the coil spring 52 is expanded in diameter by driving the hub 30, and the coil spring 52 is interposed between the coil spring 52 and the housing 29. Friction resistance is generated. As a result, the rotation of the driven-side rotator 32 is restricted, and transmission of the rotational force from the driven-side rotator 32 to the drive-side rotator 31 is prevented.

  A boss portion 37 protruding outward in the axial direction is formed at the end portion 30a (bottom portion) of the hub 30, and the first pinion 38 of the speed reduction mechanism 4 is press-fitted and fixed thereto. 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 two-way clutch 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 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. The second spur gear 44 is integrally formed with the worm 45 that constitutes one of the worm reduction gears 47. The worm 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.
By providing these spur gears 38, 42 to 44, the worm 45 is provided such that the axis P1 is along the axis P2 of the rotating shaft 12 of the electric motor 3, and the both 12, 45 are arranged in parallel with each other. It is in a state.

  The worm 45 meshes with a helical gear 46 that constitutes the other side of the worm reduction gear 47. An output shaft 50 that is rotatably coupled with the helical gear 46 is provided at a substantially radial center of the helical gear 46 so as to be along a direction orthogonal to the rotating shaft 12 of the electric motor 3. In addition, when this output shaft 50 rotates, the drive switching device which is not illustrated drives, and the drive of a four-wheel vehicle is switched to a two-wheel drive and a four-wheel drive.

  Therefore, according to the above-described embodiment, the two-way clutch 5 can prevent the rotation shaft 12 of the electric motor 3 from rotating backward, so that the self-locking of the worm speed reducer 47 can be eliminated and the transmission efficiency can be improved. become. For this reason, the worm reduction gear 47 can be reduced in size, and the actuator 1 can be reduced in size.

Further, spur gears 38 and 42 to 44 are provided between the two-way clutch 5 and the worm 45 of the worm reduction gear 47, respectively, and the worm 45 and the two-way clutch 5 are not directly connected. Moreover, by providing the spur gears 38 to 44, both 12, 45 are arranged so that the axis P1 of the worm 45 and the axis P2 of the rotating shaft 12 of the electric motor 3 are parallel to each other.
For this reason, the reaction force from the worm reducer 47 is not directly transmitted to the two-way clutch 5, so that the two-way clutch 5 is compared with the case where the worm 45 of the worm reducer 47 and the two-way clutch 5 are directly connected. It becomes possible to reduce the acting thrust force. Therefore, the load on the two-way clutch 5 is reduced, the service life is extended, and as a result, the durability of the actuator 1 can be improved.

  Further, the thrust force acting on the rotating shaft 12 can be reduced as compared with the case where the worm 45 of the worm speed reducer 47 and the rotating shaft 12 of the electric motor 3 are directly connected. For this reason, it is possible to reduce the size of the bearing 18 and the shared bearing 26 that rotatably support the rotating shaft of the electric motor 3, and as a result, the electric motor 3 can be reduced in size.

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 case where the speed reduction mechanism 4 provided between the two-way clutch 5 and the worm speed reducer 47 is configured by the four spur gears 38 and 42 to 44 is described. The speed reduction mechanism 47 should just be comprised by the 2 or more several spur gear.

  Further, in the above-described embodiment, the case where the worm reduction gear 47 is configured by the worm 45 and the helical gear 46 has been described. However, the present invention is not limited to this, and a worm wheel is used instead of the helical gear 46. Also good.

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

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Actuator 3 Electric motor 4 Reduction mechanism 5 Two-way clutch 12 Rotating shaft 45 Worm 46 Helical gear 47 Worm reducer P1, P2 Axis line

Claims (3)

With an electric motor and worm reducer,
The worm reducer is
A worm linked to the rotating shaft of the electric motor;
Consists of a helical gear or worm wheel meshed with the worm,
A two-way clutch is provided on the rotating shaft of the electric motor,
An actuator characterized in that the rotary shaft and the worm are linked via the two-way clutch. With an electric motor and worm reducer,
The worm reducer is
A worm linked to the rotating shaft of the electric motor;
Consists of a helical gear or worm wheel meshed with the worm,
A reduction mechanism comprising a plurality of gears is provided between the electric motor and the worm reduction gear;
An actuator characterized in that the rotating shaft of the electric motor and the worm are arranged in parallel, and both are arranged so that the axis of the rotating shaft and the axis of the worm are in the same direction. With an electric motor and worm reducer,
The worm reducer is
A worm linked to the rotating shaft of the electric motor;
Consists of a helical gear or worm wheel meshed with the worm,
A two-way clutch is provided on the rotating shaft of the electric motor,
A reduction mechanism comprising a plurality of gears is provided between the two-way clutch and the worm reduction gear;
An actuator characterized in that the rotating shaft of the electric motor and the worm are arranged in parallel, and both are arranged so that the axis of the rotating shaft and the axis of the worm are in the same direction.

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