JP2000291767A - Electric linear actuator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stop the movement of an action piece without over running by a simple structure. SOLUTION: This linear actuator with a male screw 6a is provided with a screw member 6 having a projection 11 projected from this male screw 6a to the diameter direction, an action piece 8 on which the female screw 8a screwed with the male screw 6a is provided and stoppers 12a, 12b provided on the arbitrary place of the action piece 8. When the action piece 8 is moved and reaches an arbitrary place, the projection 11 and stoppers 12a, 12b are constituted so as to be contacted and the movement of the action piece 8 is stopped by the contact of the projection 11 with the stoppers 12a, 12b.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric linear actuator which converts a rotational force of a screw into a screw driving force in order to move a member linearly.

[0002]

2. Description of the Related Art A conventional electric linear actuator will be described with reference to FIG. FIG. 5 is a partial side sectional view of a conventional electric linear actuator.

[0005] In FIG. 5, an electric linear actuator 101 includes a motor 102 that rotates and a motor 1.
02, a first gear 103 attached to the shaft end of the second gear 104, a second gear 104 attached in mesh with the first gear 103, and provided with a hole in the center, and a second gear 104 The key 105 is inserted through the center hole.
A part is fixedly attached to the second gear 104, a rod-shaped screw member 106 provided with an external thread 106a in an arbitrary area of the other part, and the motor 102 is attached to the outer surface,
A casing 107 in which a first gear 103 and a second gear 104 are housed, and a male screw 106a of a screw member 106 protruding from inside the casing 107 to the outside,
An operator 108 having a female screw 108a screwed with the male screw 106a, and a shaft 1 connected to the operator 108
09 and a shaft 110 for fixing the casing 107.

When the motor 102 is driven, the first gear 103 rotates, and the second gear 104 meshed with the first gear 103 rotates. Then, the screw member 106 fixed to the second gear 104 rotates. As the screw member 106 rotates, the female screw 108a screwed to the male screw 106a of the screw member 106 tends to rotate. Here, a load (not shown) is connected to the actuator 108 via a shaft 109, and the load (or the shaft 10
By making the configuration in which the operator 108 cannot rotate in the rotation direction according to 9), the operator 108 can perform linear motion by the propulsive force of the screw.

[0005] That is, by rotating the motor 102 forward or backward, the actuator 108 can be linearly moved up and down within a range where the male screw 106a is provided.

Further, for protection and safety of the main body of the electric linear actuator 101, it is necessary to limit the range in which the actuator 108 can be operated. Therefore, the upper and lower limits of the operating range of the actuator 108 are respectively limited. A switch SW is provided. (The upper limit switch is not shown.) As described above, in addition to the method of using the limit switch to limit the operation range of the operator, stoppers are provided at the upper and lower positions of the linearly moving operator. There is also a method of mechanically stopping an actuator that moves linearly. (Not shown)

As described above, in a conventional electric linear actuator, a limit switch for limiting an operating range of an operator is, for example,
There is a possibility that contact failure due to moisture or disconnection of wiring due to vibration may occur and the device may not operate. Furthermore, even if the limit switch is activated, the operator may overrun due to inertial motion, and a mechanism for overrun is required.

Also, in the method in which a stopper is provided and the operator is stopped mechanically, a large force is generated at the position to be stopped, and there is a possibility that the related parts for stopping the operator may be damaged. A long stopper is required.

[0008]

According to the present invention, there is provided, in accordance with the present invention, a screw portion provided with a male screw and having a projection radially protruding from the male screw, and a female screw engaged with the male screw. And a stopper provided at an arbitrary position of the member provided with the projection, and when the operator moves and reaches an arbitrary position, the projection is brought into contact with the stopper, and the projection and the stopper are brought into contact with each other. Provided is an electric linear actuator characterized in that an operator is stopped by contact with the electric linear actuator.

[0009]

[Operation] A protrusion is provided at an arbitrary position of a screw member. And, by providing a stopper near the female screw such as an operator or a gear or a member provided with the female screw, when the operator reaches the upper limit and the lower limit of the operation range, the rotating projection is stopped by the stopper. To stop the rotation of the screw member. Therefore, the operator does not move out of the operation range.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a side sectional view of an electric linear actuator according to the present invention. FIG.
It is -A sectional drawing. FIG. 3 is a side sectional view of an electric linear actuator according to another embodiment of the present invention. FIG.
It is BB sectional drawing of FIG.

In FIG. 1, an electric linear actuator 1 includes a motor 2 that rotates, a first gear 3 attached to a shaft end of the motor 2, and a first gear 3 similar to a conventional electric linear actuator. A second gear 4 mounted in mesh with the gear 3;
And a rod-shaped screw member 6 having a part fixed to the second gear 4 by a key 5 and having an external thread 6a provided in an arbitrary area of the other part, A motor 7 is mounted, a casing 7 in which a first gear 3 and a second gear 4 are housed, and a male screw 6a of a screw member 6 is projected from inside the casing 7 to the outside. It comprises an operator 8 provided with a female screw 8a screwed to the male screw 6a of the member 6, a shaft 9 connected to the operator 8, and a shaft 10 for fixing the casing 7. . A load (not shown) is connected to the shaft 9. The second gear 4 is rotatably supported by a bearing (not shown). The operator 8
Is supported by a slider (not shown) in the movement range of the operator 8 so as to be able to move smoothly.

At the end of the screw member 6 on the side where the male screw 6a is provided, a projection 11 is provided so as to project radially from the screw member 6. Further, the actuator 8 is provided with two stoppers 12a and 12b for stopping the rotating projection 11.

1 and 2, when the motor 2 is driven, the screw member 8 fixed to the second gear 4 rotates as in the conventional case. When the screw member 8 rotates, the operator 8 can linearly move by the propulsive force of the screw. When the operator 8 moves and reaches the upper or lower limit of the operating range of the operator 8, the protrusion 11 provided on the screw member 6 and rotating is provided.
Is in contact with the stopper 12a or the stopper 12b, and the rotation is stopped. Therefore, the operator 8 is stopped.

In FIG. 3, an electric linear actuator 21 has a motor 22 that rotates, a first gear 23 attached to a shaft end of the motor 22, and a first gear 23 that meshes with the first gear 23 and is attached. A second gear 24 having a female screw 24a provided in a central hole thereof, and a male gear which is attached through a central hole of the second gear 24 and is screwed with the female screw 24a of the second gear 24. A screw member 25 having a screw 25a provided in an arbitrary range;
5, a casing 27 in which a motor 22 is mounted on the outer surface and in which a first gear 23 and a second gear 24 are housed,
6 and a shaft 29 for fixing the casing 27.

Further, protrusions 30, 3 are provided at both ends of the screw member 25 in the range where the male screw 25a is provided.
1 is provided so as to protrude from the screw member 25. Further, in the second gear 24, the female screw 24a
In the vicinity of both openings of the hole provided with protrusions, projections 30 and 31 are provided.
There are provided two stoppers 32a and 32b for stopping the operation.

3 and 4, when the motor 22 is driven, the second gear 24 is rotated via the first gear 23. Here, the screw member 25 is connected to a load (not shown) via an operator 26 and a shaft 28. By making the screw member 25 unable to rotate in the rotation direction due to this load (or the shaft 28),
The screw member 25 can linearly move within the range in which the male screw 25a is provided by the driving force of the screw.

For example, when the screw member 25 is moved and the screw member 25 reaches the upper limit of the operation range, the rotating projection 31 provided on the screw member 25 comes into contact with the stopper 32b, and The rotation of the gear 24 can be stopped. Then, when the screw member 25 reaches the lower limit of the operation range, the projection 30 provided on the screw member 25 comes into contact with the stopper 32a, and the rotation of the second gear 24 is stopped. That is, the screw member 25 is stopped.

[0018]

According to the present invention, the screw member or gear provided with the screw is mechanically stopped, so that the operator does not overrun.

Further, since the rotating part is stopped and the actuator is stopped, the reaction force for stopping is small. Therefore, the mechanism for stopping can be reduced.

[0020]

[Brief description of the drawings]

FIG. 1 is a side sectional view of an electric linear actuator according to the present invention.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is a side sectional view of an electric linear actuator according to another embodiment of the present invention.

FIG. 4 is a sectional view taken along line BB of FIG. 3;

FIG. 5 is a partial side sectional view of a conventional electric linear actuator.

[Explanation of symbols]

 1, 21, 101: Electric linear actuator 2, 22, 102: Motor 3, 23, 103: First gear 4, 24, 104: Second gear 5, 105: Key 6, 25, 106: Screw member 7 , 27, 107 ... Casing 8, 26, 108 ... Actuator 9, 10, 28, 29, 109, 110 ... Shaft 11, 30, 31 ... Projection 12a, 12b, 32a, 32b ... Stopper

Claims (1)

[Claims] 1. A male screw screwing a rotating force of a motor,
Alternatively, it is transmitted to any of the internal threads, converts the rotational force into a screw propulsion force at the threaded portion of the screw, and in an electric linear actuator having an actuator that linearly moves by the propulsion force, an external thread is provided, A screw member provided with a projection radially projecting from the male screw; a member provided with a female screw to be screwed with the male screw; and a stopper provided at an arbitrary position of the member. When the operator moves and reaches an arbitrary position, the projection is brought into contact with the stopper, and the movement of the operator is stopped by the contact between the projection and the stopper. Linear actuator.