JP2009162371A - Actuator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an actuator which can reduce weight and cost by reducing parts count, moreover reduce noise, and improve performance. <P>SOLUTION: The actuator includes an electric motor, and a reduction gear engaged with a rotary shaft 12 of the electric motor through a clutch 5. Furthermore, a first diameter contraction section 16a of the rotary shaft 12 and a drive side rotary body 31 of the clutch 5 are rotatably supported by a jointly owned sliding bearing 26 across both of them. Additionally, in the jointly owned sliding bearing 26, a middle recessed section 53 enlarged in diameter is formed in a member corresponding to a contact part between the first diameter contraction section 16a of this sliding surface 27a and the drive side rotary body 31. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an actuator provided with a clutch that integrally assembles an electric motor and a speed reduction mechanism and prevents the reverse rotation of the rotating shaft of the electric motor by the speed reduction mechanism, and more particularly to an actuator mounted on a vehicle.

  As an actuator mounted on a vehicle, for example, there is a power window device of an automobile. In this power window device, a worm reduction device, which is a reduction mechanism, and an electric motor are connected. The worm speed reducer includes a worm coupled to the rotation shaft of the electric motor and a worm wheel meshed with the worm. By connecting this worm wheel to the output shaft of the power window device, the window glass can be opened and closed.

By the way, there is a case where a rotational force acts on the rotating shaft of the electric motor due to an external force such as the weight of the window glass or vibration during traveling of the vehicle. Therefore, a technique has been proposed in which a clutch is provided between a worm reduction gear (worm) and a rotating shaft in order to prevent the rotating shaft of the electric motor from rotating due to a rotating force caused by an external force. By providing the clutch in this way, it is possible to prevent the rotational force due to the external force from being transmitted to the rotating shaft of the electric motor (see, for example, Patent Document 1).
Japanese Patent No. 3824942

  However, in the above-described conventional technology, it is difficult to reduce the number of parts because the rotating shaft and the clutch of the electric motor are supported by separate bearings, and there is a limit to reducing the weight and cost of the actuator. There are challenges.

Accordingly, the present invention has been made in view of the above-described circumstances, and provides an actuator capable of reducing the number of parts and reducing the weight and cost.
Moreover, the actuator which can reduce a noise is provided.

In order to solve the above-described problem, the invention described in claim 1 includes an electric motor and a speed reduction mechanism linked to a rotating shaft of the electric motor via a clutch, and one end of the rotating shaft and the clutch One end of the sliding shaft is rotatably supported by one common sliding bearing straddling both, and the diameter of the shared sliding bearing is expanded to a portion corresponding to a contact portion between the rotating shaft and the clutch of the sliding surface. It is characterized in that a relief portion is formed.
By comprising in this way, it can each be rotatably supported by one common sliding bearing, without providing a bearing separately in the one end of a rotating shaft and the one end of a clutch, respectively.
In addition, since one end of the rotating shaft and one end of the clutch are supported by one common sliding bearing, it is possible to easily carry out both of them coaxially.
Further, the sliding surface of the shared sliding bearing is formed with an intermediate clearance portion at a portion corresponding to the contact portion between the rotating shaft and the clutch, so that the rotating shaft and the clutch are in contact with the sliding surface of the shared sliding bearing. It can prevent that the corner | angular part which is the outer edge of a contact part hits locally.

According to the present invention, each of the rotating shaft and the one end of the clutch can be rotatably supported by one common sliding bearing without separately providing bearings. For this reason, the number of parts of the bearing can be reduced, and it is possible to reduce the weight and cost by reducing the number of parts.
In addition, the sliding surface of the shared sliding bearing is formed with an intermediate relief portion at a portion corresponding to the contact portion between the rotating shaft and the clutch. It can prevent that the corner | angular part which is the outer edge of a contact part hits. For this reason, it can prevent that a stress is locally applied to the sliding surface of a shared sliding bearing, and can prevent abrasion of a shared sliding bearing. Therefore, it is possible to extend the life of the actuator.

  Furthermore, since one end of the rotating shaft and one end of the clutch are supported by one common sliding bearing, it is possible to easily carry out both of them coaxially. For this reason, not only can the efficiency of the assembly work be improved, but also the generation of noise due to shaft misalignment can be suppressed, and the torque transmission force from the rotating shaft to the clutch 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, 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 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 the step as it goes toward the tip of the 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 sliding bearing 26 is provided at the end 24a (bottom) of the cover 24 at the center in the radial direction.

As shown in FIG. 2, the common sliding bearing 26 is for rotatably supporting the second reduced diameter portion 16 b of the rotating shaft 12 and the clutch 5, and includes a cylindrical bearing body 27 and the bearing. The main body 27 includes a flange portion 28 formed integrally with the clutch 5 side end.
On the sliding surface 27 a of the bearing body 27, a middle escape portion 53 is formed at a portion corresponding to a portion where a second reduced diameter portion 16 b of the rotating shaft 12 and a driving side rotating body 31 of the clutch 5 described later contact. Yes. The middle escape portion 53 is formed in a concave shape so as to expand the diameter.

  In other words, the sliding surface 27 a of the bearing body 27 is prevented from contacting the corner portion 161 that is the outer edge of the end portion of the first reduced diameter portion 16 a and the corner portion 31 a that is the outer edge of the end portion of the drive side rotating body 31. A middle escape portion 53 is formed as described above. For this reason, for example, it is possible to prevent local stress from being generated on the shared sliding bearing 26 without causing a single contact with the shared sliding bearing 26 due to the axial displacement of the rotary shaft 12 or the clutch 5. .

The 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, and thereby the rotational shaft 12. Is a so-called two-way clutch that prevents reverse rotation.
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 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 not transmitted to the rotating shaft 12 in both forward / reverse directions. It is like that.

  Such a 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 rotating body. 31 and a driven-side rotator 32 that is connected to the housing 31 so as not to rotate relative to the shaft 31 and to be movable in the axial direction. The drive-side rotator 31, the driven-side rotator 32, and the housing 29 have a bottomed cylindrical shape. The 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 that is enlarged by a step is formed on the inner peripheral surface, and the flange portion 28 of the shared sliding bearing 26 can be received here.
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.

  Further, a diameter-reduced portion 34 having a diameter reduced by a step is formed on the outer peripheral surface of the drive-side rotating body 31 on the side of the electric motor 3, and the shared sliding bearing 26 rotatably supports this portion. ing. 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 clutch 5, when the driving side rotating body 31 is first driven, the driving side rotating body 31 is driven to reduce the diameter of the coil spring 52, which is connected to the driving side rotating body 31 and the driven side via the hub 30. The 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 driven-side rotator 32 is driven before the drive-side rotator 31, the driven-side rotator 32 is driven so that the coil spring 52 is expanded in diameter, and the coil spring 52 A frictional resistance force is generated between the housing 29 and the housing 29. 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 spur gear 38 of the speed reduction mechanism 4 is press-fitted and fixed thereto. The first spur gear 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 5 and a tooth portion 41 formed on the distal end side. Yes. The connecting portion 40 of the first spur gear 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 spur gear 38 is in a state of being rotatably supported by the bearing 39 via the first spur gear 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 spur gear 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 connecting portion 40 of the first spur gear 38, that is, to support the first spur gear 38 in a cantilever manner.

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

A fourth spur gear 44 is engaged with the third spur gear 43. The fourth spur gear 44 is integrally formed with the worm 45 constituting 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.
The worm 45 is provided such that the axis P1 is along the axis P2 of the electric motor 3.

  A worm wheel 46 constituting the other side of the worm reduction gear 47 is engaged with the worm 45. An output shaft 50 that is rotatably connected with the worm wheel 46 is provided at a substantially central position in the radial direction of the worm wheel 46 so as to extend along a direction orthogonal to the rotation 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 first reduced diameter portion 16a of the rotating shaft 12 and the driving-side rotating body 31 of the clutch 5 are not provided with separate bearings, respectively. 5 can be rotatably supported. For this reason, the number of parts of the bearing can be reduced, and the weight and cost can be reduced by reducing the number of parts.

  In addition, since the first reduced diameter portion 16a of the rotary shaft 12 and the drive-side rotary body 31 of the clutch 5 are supported by one common sliding bearing 26, both the shafts 12 and 5 can be easily aligned. become. For this reason, not only can the efficiency of the assembly work be improved, but also the generation of noise due to shaft misalignment can be suppressed, and the torque transmission force from the rotary shaft 12 to the clutch 5 can be improved.

  Further, the bearing body 27 of the shared sliding bearing 26 is formed with a middle escape portion 53 on the sliding surface 27a. Moreover, the intermediate escape portion 53 is formed so that the intermediate escape portion 53 avoids contact between the corner portion 161 of the first reduced diameter portion 16a and the corner portion 31a of the drive side rotating body 31. For this reason, it becomes possible to prevent the generation of local stress on the shared sliding bearing 26 due to the axial displacement of the rotary shaft 12 and the clutch 5, and wear of the shared sliding bearing 26 can be prevented. Therefore, as a result, the life of the actuator 1 can be extended.

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 second reduced diameter portion 16b of the rotary shaft 12 is chamfered, while the drive-side rotating body 31 of the clutch 5 has a shape corresponding to the second reduced diameter portion 16b. The case where the connecting hole 33 is formed has been described. However, the present invention is not limited to this, and it is only necessary that the rotary shaft 12 and the drive-side rotating body 31 be relatively unrotatable and movable in the axial direction. What is necessary is just to form in the polygon and the connection hole 33 of the drive side rotary body 31 corresponding to this.

  Furthermore, in the above-described embodiment, the reduced diameter portion 35 of the driving side rotating body 31 is flattened, while the driven side rotating body 32 is formed with a connection hole 36 corresponding to the reduced diameter portion 35. Explained the case. However, the present invention is not limited to this, and it is only necessary that the drive-side rotator 31 and the driven-side rotator 32 are not relatively rotatable and can move in the axial direction. Is formed in a two-sided chamfering or a polygonal cross-section, and the connection hole 36 of the driven side rotating body 32 may be formed correspondingly.

It is sectional drawing which shows the structure of the actuator in embodiment of this invention. It is the A section enlarged view of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Actuator 3 Electric motor 4 Deceleration mechanism 5 Clutch 12 Rotating shaft 16a 1st diameter-reduction part 161 Corner | angular part 26 Shared sliding bearing 27a Sliding surface 31 Drive side rotary body 31a Corner | angular part 53 Middle escape part

Claims (1)

An electric motor;
A speed reduction mechanism linked to the rotating shaft of the electric motor via a clutch,
One end of the rotating shaft and one end of the clutch are rotatably supported by one shared sliding bearing straddling both,
The shared sliding bearing is an actuator characterized in that a middle escape portion having an enlarged diameter is formed at a portion of the sliding surface corresponding to a contact portion between the rotating shaft and the clutch.

Images