JP2003314651A - Actuator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an actuator having compact construction and high efficiency, while driving an offset driven member. <P>SOLUTION: A supporting member 27 suppresses the rotation of a link 25 around the axis of a screw shaft 11, eliminating the need for a rotation stopper for the screw shaft 11. Thus, construction of the actuator 100 can be simplified and cost is reduced. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an actuator, for example, a power window of an automobile, an electric parking brake device, a caliper pushing mechanism of an electric disc brake device, a cam phase converting mechanism in a valve timing varying device of an engine, a belt CVT pulley. Drive mechanism, other industrial winches, hoists, cranes,
The present invention relates to an actuator using an electric motor as a power source, which can be used in various positioning devices.

[0002]

2. Description of the Related Art For example, an actuator such as an electric parking brake drive device for reducing the burden on a driver by operating a parking brake of a vehicle by using the power of an electric motor is known. As such an actuator, there has been proposed one in which a pulley is rotated by an electric motor to wind up a cable to operate a parking brake, and a cable is rewound to release the parking brake (see JP 2001-106060 A).

[0003]

The actuator disclosed in the above publication uses the worm gear and the worm hole to reduce the power from the electric motor and transmit it to the parking brake. When power transmission is performed using a worm gear and a worm wheel, a large reduction ratio can be achieved, and by appropriately designing the twist angle of the worm, it is possible to prevent the power from the parking brake from being transmitted to the electric motor side. There is.

However, reversing the above advantages, the worm gear and the worm hole have the drawback of low transmission efficiency, and therefore the power of the electric motor must be increased in order to operate the parking brake. Therefore, there is a problem that the electric motor becomes large and power cannot be saved.

In order to solve such a problem, the present inventor has found that when the ball screw mechanism consisting of a nut and a screw shaft and the output shaft of the electric motor rotate with respect to the nut, the power from the output shaft to the nut is increased. We have developed an actuator that includes a clutch mechanism that allows transmission and prohibits power transmission from the nut to the electric motor when the nut rotates with respect to the output shaft of the electric motor. Such an actuator has a compact structure and high efficiency, but when it is applied to an automatic clutch release mechanism, a two-wheel drive / four-wheel drive switching device in a four-wheel drive mechanism, etc. In many cases, the member is offset from the axis of the screw shaft, and in such a case, there is a problem of how to attach the screw shaft of the ball screw mechanism.

The present invention has been made in view of the above problems, and an object of the present invention is to provide an actuator having a compact structure and high efficiency, which is capable of driving an offset driven member.

[0007]

The actuator of the present invention is an actuator for driving a driven member, wherein a housing, an electric motor having an output shaft attached to the housing, and an output shaft of the electric motor are provided. , Permitting power transmission from the output shaft to the rotating body when rotating with respect to the rotating body, and from the rotating body to the electric motor when rotating with respect to the output shaft of the electric motor. A clutch mechanism for prohibiting power transmission to a motor, a conversion mechanism for converting rotational displacement of the rotating body into axial displacement of a shaft and transmitting the displacement, and an axial displacement of the shaft for swinging displacement of a member. The link mechanism includes a link that is swingably connected to the shaft, and a limiting portion that limits operations other than the swing of the link with respect to the case. Characterized in that it.

[0008]

According to the actuator of the present invention, in an actuator for driving a driven member, a housing, an electric motor having an output shaft attached to the housing, and an output shaft of the electric motor with respect to a rotating body. When rotating, it permits power transmission from the output shaft to the rotating body, and when the rotating body rotates with respect to the output shaft of the electric motor, it transmits power from the rotating body to the electric motor. A clutch mechanism for inhibiting, a conversion mechanism for converting the rotational displacement of the rotating body into an axial displacement of a shaft and transmitting the same, and a link mechanism for converting the axial displacement of the shaft into a swing displacement of a member. However, since the link mechanism has a link that is swingably connected to the shaft and a limiting portion that limits operations other than the swing of the link with respect to the case, Even when the member is offset with respect to the shaft, the restricting portion restricts motions other than the swing of the link, so that the link reliably swings to drive the driven member. It becomes possible to drive. At this time, the restricting portion restricts operations other than rocking of the link, and as a result, rotation of the shaft is blocked. For example, a ball screw mechanism,
When a mechanism for converting the rotational displacement of the nut into the axial displacement of the screw shaft is used, it is not necessary to provide a rotation stopper or the like for the screw shaft, which is originally required, and the cost can be reduced.

Further, it is preferable that the converting mechanism includes a ball screw mechanism having a screw shaft as the shaft and a screw shaft having a nut as the rotating body. The rotary body may include a rotary driven member described later.

Further, it is preferable that the limiting portion includes a pair of supporting members which are attached to the housing and are integrated with each other so as to guideably sandwich the link.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a sectional view of an actuator 100 according to the first embodiment. 2 is shown in FIG.
FIG. 2 is a diagram showing the configuration of FIG. FIG. 3 is a cross-sectional view when the actuator 100 of FIG. 1 is operated and brought into different states.

In FIG. 1, a housing C filled with oil or grease has an opening Ca. A substantially cylindrical clutch housing 1B is fitted into the opening Ca while interposing an O-ring 1C exhibiting a sealing function, and a bolt 1D.
It is installed by. Clutch housing 1B
1 has a cylindrical motor housing 1A mounted coaxially at the left end in FIG. The motor housing 1A and the clutch housing 1B form a housing. The left end of the motor housing 1A in FIG. 1 is closed by a lid 1E. The stator 2b is fixedly arranged on the inner circumference of the motor housing 1A, and the rotor 2 is arranged on the outer circumference of the rotating shaft 3 which is the output shaft.
c is fixedly arranged. Stator 2b, rotor 2c,
The rotating shaft 3 constitutes the electric motor 2.

The rotary shaft 3 has a lid 1 on the left end side in FIG.
It is rotatably supported by a bearing 9A attached to E. The bearing 9A is biased to the right in FIG. 1 by the washer spring 20 with respect to the motor housing 1A.

In the vicinity of the right end of the rotary shaft 3 in FIG.
a is formed, and four claw portions 3b equally arranged in the circumferential direction extend from the large diameter portion 3a to the right in FIG. Large diameter part 3a
The outer peripheral surface of is rotatably supported by the bearing 9B with respect to the motor housing 1A and the clutch housing 1B. The outer peripheral surface of the bearing 9B is the motor housing 1A.
And the ends of the clutch housing 1B, respectively,
This is the standard for the spigot fitting, and thereby improves the coaxiality between the motor housing 1A and the clutch housing 1B.

An outer ring 5 is provided on the inner peripheral surface of the clutch housing 1B, and a pin 21 is planted in the clutch housing 1B.
It is fixed by. The outer ring 5 is sandwiched by bearings 9A and 8 in the axial direction. The bearing 8 rotatably supports the cylindrical rotary driven member 4 with respect to the clutch housing 1B. As for the clutch mechanism CM that selectively transmits power between the rotary shaft 3 and the rotary driven member 4, FIG.
Will be described later with reference to.

A nut 10 is provided inside the rotary driven member 4.
Is fixed by a pin 22 that is planted in the rotary driven member 4. A screw shaft 11 penetrates through the nut 10. The screw shaft 11 has a central screw portion 11b and round shaft portions 11c arranged on both sides in the axial direction thereof. A thread groove (not shown) is formed on the inner peripheral surface of the hollow nut 10, and a large number of balls (not shown) are formed in a spiral space formed by the thread groove of the nut 10 and the thread portion 11b of the screw shaft 11. )
Are arranged so that they can roll freely. During operation, the passage 10a for returning the ball from one end of the nut 10 to the other end is
It is provided outside of. Nut 10 and screw shaft 11
And a ball (not shown) constitute a ball screw mechanism which is a conversion mechanism. Further, the nut 10 and the rotary driven member 4
And constitute a rotating body.

A round shaft portion 11c on the left side of the screw shaft 11 in FIG.
Is freely movable in and out of a blind hole 3c formed in the center of the rotary shaft 3, and is supported by a bush 23. The outer peripheral surface of the right round shaft portion 11c is sealed with respect to the clutch housing 1B by a seal 24, and the end portion thereof is on the left side of the clutch housing 1B (in the housing C) in FIG.
Overhangs.

As shown in FIG. 2, the upper end of the link 25 is bifurcated, and the tip of the right round shaft portion 11c in FIG. Are connected. Retaining rings 52 are provided at both ends of the pin 26 to prevent the pin from coming off. Long hole 2 in the middle of the link 25
5a (FIG. 3) is formed. The lower end of the link 25 is
It is connected to a driven member (not shown).

The limiting member 27 attached to the clutch housing 1B with bolts 28 has a pair of arms 27a extending in a crank shape as viewed in FIG. In this state, the pin 50 penetrates the lower end of the arm 27a and the elongated hole 25a of the link 25. Retaining rings 51 are provided at both ends of the pin 50 to prevent the pin 50 from coming off.

FIG. 4 is a view of the structure of FIG. 1 taken along line IV-IV and viewed in the direction of the arrow. The clutch mechanism CM as a clutch mechanism includes an outer ring 5, a rotation driven member 4, four (not limited to) claw portions 3b, and four (not limited to) rolling elements (rollers). 6 and a plurality of cam surfaces 31.

The outer ring 5 has an inner peripheral surface as a friction surface 5a. The friction surface 5a has a property like an outer ring raceway of a general cylindrical roller bearing, and has a smooth surface. Such an outer ring 5 is fixed to the inner peripheral surface (FIG. 1) of the clutch housing 1B.

On the outer peripheral surface of the rotary driven member 4, here, 4
The cam surfaces 31 and the engaging recesses 35 are alternately formed at equal intervals in the circumferential direction. Each cam surface 31 is
The central portion in the circumferential direction is arranged closest to the axis and has a shape inclined so as to separate from the axis as it rotates in both directions. The shape of each cam surface 31 is preferably, as shown in FIG. 4, both end portions in the circumferential direction are both end convex curved surface portions 36 curved in the opposite direction to the rolling surface of each rolling element 6, respectively. A shape in which the central portion in the circumferential direction is a central concave curved surface portion 37 in which the edges of the pair of both end convex curved surface portions 36 are smoothly continuous and curved in the same direction as the rolling surface of each rolling element 6 is adopted. To do.
In the case of this example, as will be described later, the convex curved surface portions 36 on both ends are
Reference numeral 36 denotes a cam surface for making the rolling elements 6 bite into the friction surface 5a of the outer ring 5, and each rolling element 6 has two cam surfaces. .

It should be noted that the reason why both circumferential end portions of each cam surface 31 are convex curved surfaces that are curved in the opposite direction to the rolling surface of each rolling element 6 is that each rolling element 6 has a cam surface 31 and a friction surface 5a. This is because it is easy to set the contact angle between each of the cam surfaces 31 and the rolling surface of each of the rolling elements 6 to an appropriate value when it bites into between.
Further, the central concave curved surface portion 37 is formed on a partial cylindrical surface to prevent the cross-sectional shape of the continuous portion between the edges of the convex curved surface portions 36 at both ends from becoming sharp. The reason for this is to reduce the stress concentration in the continuous portion at the time of torque load and prevent the rotary driven member 4 from being damaged. However, the shape of each cam surface 31 is not limited to that shown in FIG. 4, and is arbitrary as long as necessary performance including durability can be secured.

Further, each claw portion 3b is axially directed toward the rotary driven member 4 at the end of the rotary shaft 3 (to the right in FIG. 1).
In the protruding state, they are evenly arranged in the circumferential direction. As is clear from FIG. 4, each of the claw portions 3b has a substantially arcuate cross section, and has a shape in which circular tubes centering on the central axis of the rotating shaft 3 are cut out at equal intervals. ing. A pocket 39 for holding each rolling element 6 is provided between the claw portions 3b adjacent to each other in the circumferential direction. The width W1 of the pocket 39 is sufficiently larger than the outer diameter φD1 of each rolling element 6 (W1> D1).

The width of each claw 3b in the circumferential direction is
It is large on the outer diameter side and small on the inner diameter side. The reason for this is that the width W1 of each pocket 39 is made equal from the inner diameter side to the outer diameter side, and it is effective that a spring 40, which will be described later, which is locked to each claw portion 3b, is displaced outward by centrifugal force. This is to prevent it. In addition, engaging projections 3d are formed on the inner peripheral surfaces of the respective claw portions 3b in the circumferential direction so as to project inward in the radial direction. In the assembled state of the clutch mechanism CM, each engagement protrusion 3d engages with the engagement recess 35 formed on the outer peripheral surface of the rotation driven member 4. Because of this,
The width W2 of each engaging protrusion 3d is sufficiently smaller than the width W3 of each engaging recess 35 (W2 <W3).

Therefore, in the assembled state of the clutch mechanism CM, the engagement convex portions 3d and the engagement concave portions 35 engage with each other so as to be relatively displaceable in the circumferential direction. The rotation shaft 3 and the rotation driven member 4 are combined so as to be relatively displaceable with respect to the rotation direction.

Incidentally, the structure in which the rotary shaft 3 and the rotary driven member 4 are engaged with each other in a state where they are relatively displaced by a predetermined angle is due to the engagement between the engaging concave portion 35 and the engaging convex portion 3d as described above. Not limited to this, other structures may be adopted. For example, a concavo-convex engaging portion that engages with each other can be provided in a portion of the rotary shaft 3 and the rotary driven member 4 facing each other, which is axially displaced from the rotary driven member 4. In the case of such a configuration, the space for each engagement recess 35 formed on the outer peripheral surface of the rotation driven member 4 in the illustrated example is not necessary, so that more cam surfaces can be formed. By forming more rolling elements, the torque capacity of the clutch mechanism CM can be increased.

Each rolling element 6 is like a cylindrical roller that constitutes a general cylindrical roller bearing, and is made of a hard metal such as high carbon chrome bearing steel, and the outer periphery of the driven member 4 to be rotated. It is provided in the pocket 39 between the claw portions 3b that are circumferentially adjacent to each other in the annular space 42 between the surface and the inner peripheral surface of the outer ring 5. An elastic material such as a spring 40 shown in a perspective view of FIG. 5 is attached to each of the claw portions 3b. Spring 40 formed by bending and forming an elastic metal plate such as stainless spring steel
Includes one base portion 43 and a plurality (four in the illustrated example) of elastic pressing pieces 44. Of these, the base portion 43 has a shape capable of abutting against each claw portion 3b without rattling. Further, each elastic pressing piece 44 has its base end connected to the base portion 43, and has an elastic force in a direction to displace each tip end portion away from the base portion 43 in a free state.

The spring 40 as described above, as shown in FIG.
By externally fitting the base portion 43 to each of the claw portions 3b, the base portion 43 can be attached to each of the claw portions 3b. In this way, the rolling elements 6 are respectively placed between the elastic pressing pieces 44 of the spring 40 mounted on the respective claw portions 3b, and the elastic pressing pieces 44 are arranged between them.
It is clamped while being elastically displaced. In this state, the rolling elements 6 are elastically pressed by the elastic pressing pieces 44 of the springs 40 at the opposite positions in the circumferential direction at both axial ends with the same force. Therefore, each rolling element 6 has a pocket 3 between the claw portions 3b adjacent to each other in the circumferential direction when no external force is applied.
It is located at the central portion in the circumferential direction among the nine. It should be noted that each elastic pressing piece 44 presses each rolling element 6 substantially straight in the circumferential direction. That is, both side surfaces in the circumferential direction of each claw portion 3b are parallel to each other for each side surface forming each pocket 39, and each elastic pressing piece 44 is provided parallel to each side surface. Therefore, of the forces applied from the elastic pressing pieces 44 to the rolling elements 6, the component force in the diametrical direction of the rotating shaft 3 is extremely small. In addition, each spring 40 is connected to each claw portion 3b.
The outer diameter of the base portion 43 of each of the springs 40 is smaller than the inner diameter of the outer ring 5 in a state where the outer ring 5 is sunk. Therefore, the rotating shaft 3
Even when is rotated, the outer peripheral surface of the base portion 43 of each spring 40 does not rub against the friction surface 5a of the outer ring 5.

Next, the clutch mechanism C configured as described above.
The operation of the actuator incorporating M will be described. First, in the state shown in FIG. 1, when the rotating shaft 3 is rotated by energizing the electric motor 2, the clutch mechanism CM moves to the position shown in FIG.
The state shown in FIG. That is, in this case, the rotating shaft 3 rotates, for example, in the counterclockwise direction of FIG. 4A, and the engaging convex portions 3d provided on the claw portions 3b of the rotating shaft 3 cause the rotating driven member 4 to rotate. It is displaced to the circumferential end of each engaging recess 35 provided in the. At this time, the inner side surface of each engaging concave portion 35 and the outer side surface of each engaging convex portion 3d abut (engage the engaging portion), and the rotation of the rotary shaft 3 is transmitted to the rotary driven member 4 as it is. Therefore, the rotation driven member 4 rotates in the same direction as the rotation shaft 3 at the same speed.

As described above, until the outer side surface of each engaging convex portion 3d and the inner side surface of each engaging concave portion 35 come into contact with each other, the rotary shaft 3 slightly rotates with respect to the rotary driven member 4, As shown in FIG. 4A, each rolling element 6 is located in front of the rotational center of the rotary shaft 3 with respect to the circumferential center position of each cam surface 31 provided on the outer peripheral surface of the rotation driven member 4. Move a little to the left of (a). As a result, each rolling element 6 is guided by the both end convex curved surface portions 36 of each cam surface 31, and is displaced outward in the diametrical direction of the rotary driven member 4. Thereby, the rolling surface of each rolling element 6 and the friction surface 5a of the outer ring 5 contact.

In this way, when the rotating shaft 3 and the driven member 4 rotate in the same direction with the rolling surface of each rolling element 6 and the friction surface 5a of the outer ring 5 contacting each other, each rolling element 6 Will tend to be displaced toward the central concave curved surface portion 37, which is the central portion of each cam surface 31. That is, when the rotary shaft 3 and the rotary driven member 4 rotate in the same direction while the rolling surface of each rolling element 6 and the friction surface 5a of the outer ring 5 are in contact with each other, each rolling element 6 is Based on the frictional engagement between the moving surface and the friction surface 5a, it tries to stay in the same position.

On the other hand, since the rotary driven member 4 having the cam surfaces 31 formed thereon rotates counterclockwise in FIG. 4A, the rolling elements 6 are arranged on both side surfaces of the claw portions 3b. Among the elastic pressing pieces 44, the elastic pressing pieces 44 on the front side surface in the rotational direction are displaced rearward in the rotational direction with respect to the driven member 4 while increasing the amount of compression. Therefore, each rolling element 6 does not mesh between each cam surface 31 and the friction surface 5a. As a result, each rolling element 6 moves to a portion where the distance between each cam surface 31 and the friction surface 5a is large, and rolls at this portion. In this state, the rotary shaft 3 and the rotary driven member 4 are rotatable inside the outer ring 5, and rotation can be transmitted from the rotary shaft 3 to the rotary driven member 4.

Due to the principle of the ball screw mechanism, the rotational displacement of the rotary driven member 4 is smoothly converted into the axial displacement of the screw shaft 11. The upper end of the link 25 attached to the end portion of the screw shaft 11 in FIG. 1 moves together with the screw shaft 11, but the long hole 25a thereof is provided with the support member 2 via the pin 50.
Since the movement is restricted by 7, the link 25 swings as a result, as shown in FIG. 3, and the driven member (not shown) attached to the lower end of the link 25 can be driven. In the state shown in FIG. 3, the screw part 11 b of the screw shaft 11 is connected to the hole 3 of the rotary shaft 3.
Although it serves as a stopper by coming into contact with the periphery of c, a buffer member may be provided at the end of the screw portion 11 in order to suppress damage to the screw portion 11b.

According to the present embodiment, since the support member 27, which is the limiting portion, suppresses the rotation of the link 25 around the axis of the screw shaft 11, it is not necessary to provide the screw shaft 11 with a rotation stopper. Therefore, the structure of the actuator 100 can be simplified and the cost can be reduced. The reason why the support member 27 side, rather than the screw shaft 11 side, is an elongated hole is to prevent the screw shaft 11 from rotating.

When the frictional force acting on the abutting portion between the rolling surface of each rolling element 6 and the friction surface 5a is large, each rolling element 6
However, each elastic pressing piece 44 on the front side surface side in the rotation direction of each claw portion 3b
May be crushed completely. Even in such a state, the width W2 of each engagement protrusion 3d and the width W3 of each engagement recess 35 are preferably set so that each rolling element 6 does not bite between each cam surface 31 and the friction surface 5a. Corresponding to the difference (W2 <W3),
The size δ of the displaceable gap of each engagement protrusion 3d in each engagement recess 35 is regulated. That is, by each rolling element 6, each elastic pressing piece 44 on the front side surface side in the rotation direction of each claw portion 3b.
Even if it is assumed that they are elastically deformed to the state of coming into contact with each of these claw portions 3b, the rolling surface of each rolling element 6 and the both-end convex curved surface portions 36 in the rearward direction of rotation (to the right in FIG. 4 (a)). Alternatively, the dimensional relationship is such that a gap can be secured between the friction surface 5a.
In other words, each rolling element 6 has each cam surface 31 and friction surface 5a.
The dimensional relationship is such that the rotation transmission from the rotation shaft 3 to the rotation driven member 4 is not disabled by cutting in between the rotation shaft 3 and the rotation driven member 4.
The above description has been made with respect to the case where the rotary shaft 3 rotates counterclockwise, but the case where the rotary shaft 3 rotates clockwise also operates in the same manner except that the rotation direction is reversed.

Next, although the electric motor 2 is stationary and the rotary shaft 3 is stationary, a thrust load is applied to the screw shaft 11 from the driven member via the link 25, and the nut 10 and the rotary shaft are rotated. A case where a rotational force is applied to the driven member 4 will be described with reference to FIG. In this case, before the rotation driven member 4 rotates counterclockwise in FIG. 4B, the inner side surface of each engagement concave portion 35 and the outer side surface of each engagement convex portion 3d come into contact with each other. That is, before the rotation of the rotation driven member 4 is transmitted to the rotation shaft 3 as it is, each rolling element 6 bites between each cam surface 31 and the friction surface 5a. Moreover, in this case, a force is applied from each cam surface 31 to each rolling element 6 in a direction in which each rolling element 6 bites between each cam surface 31 and the friction surface 5a. In other words, no force acts in the direction in which each rolling element 6 is displaced to the central portion in the circumferential direction of each cam surface 31. The force exerted by the spring 40 is extremely small as compared with the force required to rotate the rotary shaft 3, and can be ignored in this case.

Therefore, each rolling element 6 bites between each cam surface 31 and the friction surface 5a to prevent the rotation of the rotation driven member 4. Therefore, the rotary driven member 4 does not rotate any more, and the rotation of the rotary driven member 4 is not transmitted to the rotary shaft 3. As a result, even if the conversion mechanism provided in the actuator 100 is a highly efficient ball screw mechanism, the link 25 can be supported without displacement as long as the electric motor 2 is stopped.
Although the above description has been given of the case where the driven member 4 rotates counterclockwise, it also operates in the same manner when it rotates clockwise, except that the rotation direction is reversed.

In the clutch mechanism CM incorporated in this example, each rolling element 6 surely bites between each cam surface 31 and the friction surface 5a regardless of the direction in which the driven member 4 rotates. The reason is that the spring 40 presses each rolling element 6 from both sides in the circumferential direction to regulate the position of each rolling element 6 in the circumferential direction. On the other hand, a structure in which the spring presses the rolling element in only one direction is conceivable, but in such a case, when the rotation driven member rotates in the direction opposite to the pressing direction of this spring (that is, Only when the load is constantly applied in a predetermined direction), the rolling element can be surely bited. In other words, in the case of this example, since each rolling element 6 is pressed from both sides in the circumferential direction, even if the rotary driven member 4 rotates in any direction, all the rolling elements 6 will be transferred to each cam. It is possible to surely bite between the surface 31 and the friction surface 5a. On the other hand, even if the spring is omitted altogether, the same operation as in the illustrated example can be performed. However, in this case, in addition to the unstable operation, each rolling element may rattle between the cam surface and the friction surface during non-operation to generate abnormal noise. If each rolling element 6 is pressed by each spring 40 as in this example, such a problem does not occur.

FIG. 6 is a sectional view of an actuator according to the second embodiment. As shown in FIG. 6, the actuator 200 of the present embodiment is different from the above-described embodiment mainly in that an electromagnetic brake MB as a clutch mechanism is provided instead of the clutch device CM, and
The description of the common main components will be omitted by attaching the same reference numerals. Further, since the structure of the electromagnetic brake is well known, detailed description will be omitted.

The right end of the rotary shaft 103 of the electric motor 2 in FIG. 6 is directly fixed to the rotary driven member 4 (which constitutes a rotary body together with the nut 10) with a pin bolt 130 so that the rotary shaft 103 cannot rotate. The left end of the rotary shaft 103 receives a braking force from the electromagnetic brake MB installed in the motor housing 1A. The bearing that supports the large diameter portion 103a of the rotating shaft 103 is omitted. When the electric motor 2 is energized, the electromagnetic brake MB does not apply a braking force to the rotating shaft 103 (allows its rotation), whereby the link member 2
5 is oscillated, but when the electric power to the electric motor 2 is cut off, a braking force is applied to the rotating shaft 103 (the rotation thereof is prohibited), so that the link member is irrespective of the load of the driven member. It is possible to keep 25 in place.

Although the present invention has been described with reference to the embodiments, the present invention should not be construed as being limited to the embodiments, and it goes without saying that appropriate modifications and improvements are possible. .

[0043]

According to the actuator of the present invention, in an actuator for driving a driven member, a housing, an electric motor having an output shaft attached to the housing, and an output shaft of the electric motor are provided in a rotating body. When rotating with respect to each other, power transmission from the output shaft to the rotating body is allowed, and when rotating with respect to the output shaft of the electric motor, power from the rotating body to the electric motor is allowed. A clutch mechanism for inhibiting transmission, a conversion mechanism for converting rotational displacement of the rotating body into axial displacement of a shaft and transmitting the same, and a link mechanism for converting axial displacement of the shaft into swing displacement of a member. Since the link mechanism has a link swingably connected to the shaft and a restricting portion that restricts an operation other than the swing of the link with respect to the case, Even if the driven member is offset with respect to the shaft, the restricting portion restricts motions other than the swing of the link, so that the link reliably swings to drive the driven member. It becomes possible to drive the member. At this time, since the restricting part restricts operations other than the swing of the link, the rotation of the shaft is blocked as a result, and the rotational displacement of the nut is prevented by the rotation of the screw shaft, such as a ball screw mechanism. When a mechanism for converting to axial displacement is used, it is not necessary to provide a rotation stopper or the like for the screw shaft, which is originally necessary, and cost can be reduced.

[Brief description of drawings]

FIG. 1 is an actuator 10 according to a first embodiment.
It is sectional drawing of 0.

FIG. 2 is a diagram showing the configuration of FIG. 1 viewed in the direction of arrow II.

3A and 3B are cross-sectional views when the actuator of FIG. 1 is operated to be in different states.

FIG. 4 is a diagram of the configuration of FIG. 1 taken along line IV-IV and viewed in the direction of the arrow.

FIG. 5 is a perspective view of a spring member 40.

FIG. 6 is a sectional view of an actuator according to a second embodiment.

[Explanation of symbols] 1A motor housing 1B clutch housing 2 electric motor 3, 103 rotation axis 4 Rotary driven member 5 outer ring Around 6 10 nuts 11 screw shaft

Claims (3)

[Claims] 1. An actuator for driving a driven member, comprising: a housing; an electric motor having an output shaft attached to the housing; and an output shaft of the electric motor rotating with respect to a rotating body. A clutch mechanism that permits power transmission from the output shaft to the rotating body and prohibits power transmission from the rotating body to the electric motor when the rotating body rotates with respect to the output shaft of the electric motor A link mechanism that converts the rotational displacement of the rotating body into axial displacement of a shaft and transmits the displacement, and a link mechanism that converts the axial displacement of the shaft into swing displacement of a member. An actuator, wherein the mechanism includes a link swingably connected to the shaft, and a limiter that limits operations of the case other than the swing of the link with respect to the case. 2. The actuator according to claim 1, wherein the conversion mechanism includes a ball screw mechanism having a screw shaft as the shaft and a nut as the rotating body. 3. The actuator according to claim 1, wherein the limiting portion includes a pair of support members that are attached to the housing to be integrated with each other and that guideably sandwich the link. .