JPH0559030U - Actuator - Google Patents

Abstract

(57) [Abstract] [Purpose] The present invention relates to an actuator that linearly moves an output shaft with a screw structure, and an object thereof is to enable a forced stop with a simple structure and to reliably start the output shaft. [Structure] A convex portion 6b is formed on the outer periphery of an inner screw member 6 having an inner screw screwed to the outer screw of the output shaft 7 on the inner periphery thereof, and a rotary shaft 1 of the motor is formed on the outer periphery.
A convex portion 5c is formed on the inner periphery of the gear portion 5 having a gear 5a that meshes with the pinion 4 fixed to a, and the gear portion 5 is fixed to the inner screw member 6 by the convex portion 6b and the convex portion 5c. The angle θ is configured to be freely rotatable.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an actuator, and more particularly to an actuator in which a screw structure causes a linear movement of an output shaft.

[0002]

[Prior Art]

 An actuator that performs a reciprocating linear motion fixes a pinion on the rotating shaft of a motor, and engages a gear on the outer circumference with a gear on the outer circumference and a gear on the inner circumference that forms an internal screw to form the inner screw. The output shaft is formed by screwing an output shaft whose outer circumference is formed on a male screw part (outer screw).

The rotation of the motor causes the gear to rotate via the pinion, causing the inner screw to rotate.

The output shaft screwed into the inner screw blocks rotation, and therefore, the rotation of the inner screw causes the output shaft to linearly move.

Conventionally, in this type of actuator, since the tightening torque and the loosening torque of the screw mechanism exist, it is usual not to use the forcible stop structure.

For example, the screw mechanism is configured so that the screw mechanism is not tightened when the motor is stopped, or a continuous operation structure is provided without providing a forced stop mechanism.

Further, in the case where the structure is forcibly stopped, the screw mechanism is a ball screw system to minimize the friction coefficient of the screw sliding portion.

[0008]

[Problems to be solved by the device]

 However, in the conventional actuator of this type, when the output shaft is forcibly stopped via a stopper or the like, the screw is applied with a torque greater than the maximum torque of the motor due to the inertial force of the motor.

For example, the tightening torque is about 4 to 5 times the maximum torque. In addition, the loosening torque with respect to the tightening torque varies with the friction coefficient, but is about 80% of the tightening torque.

This is 3 to 4 times the maximum torque of the motor, and in this state (loosening torque> starting torque), starting cannot be performed only by the starting torque of the motor.

Therefore, in the case of forcibly stopping the structure, it is necessary to minimize the friction coefficient of the screw sliding part, such as the ball screw system, to reduce the tightening torque and the loosening torque of the screw. It will increase the cost.

There is a problem that the use condition is restricted in the structure in which the motor is stopped and the continuous operation structure without forced stop is used and the tightening torque and the loosening torque are not generated.

The present invention has been made in view of the above points, and an object of the present invention is to provide an actuator that can perform a forced stop with a simple structure and can reliably start an output shaft.

[0014]

[Means for Solving the Problems]

 According to the present invention, in an actuator that linearly reciprocates the output shaft by rotating a screwing part screwed with a male screw part formed on the output shaft according to the rotation of a motor, the female screw part is used. Is formed on the inner periphery and a first protrusion is formed on the outer periphery, and a screw member and a second protrusion that engages with the first protrusion formed on the female screw member on the inner periphery And a gear portion that is configured to be rotatable by a predetermined angle with respect to the female screw member, is engaged with the motor, and is rotated according to the rotation of the motor.

[0015]

[Action]

 The gear portion rotates by a predetermined angle in an unloaded state to obtain sufficient inertia, and then the second convex portion collides with the first convex portion formed on the female screw member to activate the female screw member. For this reason, even if the female screw member and the output shaft are tightened, it is possible to obtain a torque that loosens them.

[0016]

【Example】

 FIG. 1 shows a sectional view of an embodiment of the present invention. In the figure, reference numeral 1 denotes a motor, which is, for example, a direct current motor. The motor 1 is housed in a housing case 2, and is similarly housed in a housing case 2 and electrically connected to the outside through a circuit board 3 on which a motor protection circuit is formed.

A pinion 4 is fixed to the rotating shaft 1 a of the motor 1.

Reference numeral 5 denotes a gear, and the gear 5 has a tooth portion 5 a on an outer peripheral portion, and the gear portion 5 is arranged in the storage case 2 so that the tooth portion 5 a meshes with the pinion 4. Further, the gear 5 has a stepped hole 5b formed in the inner peripheral portion thereof.

The stepped hole 5b of the gear 5 is fitted with an inner screw member 6 having a stepped portion 6a formed on the outer periphery thereof so as to engage with the stepped hole 5b of the gear 5.

Further, as shown in FIG. 3, the stepped hole 5 b of the gear 5 is formed with a convex portion 5 c, and the outer peripheral stepped portion 6 a of the inner screw member 6 is also similarly level with the convex portion 5 c of the gear 5. In addition, the convex portion 6b is formed with the same rotation locus.

The gear 5 is configured to be rotatable by θ based on the inner screw member 6 by the convex portion 5c and the convex portion 6b.

A female screw 6c is cut on the inner circumference of the inner screw member 6, and an output shaft 7 formed of a male screw 7a on the outer circumference is screwed onto the female screw 6c.

A guide pin 7 b is provided at the lower end of the output shaft 7 to prevent the output shaft 7 from rotating along the guide groove 2 a provided in the storage case 2. Further, the guide pin 7b is in contact with the inner screw member 6 so as to also perform the function of stopping the linear movement of the output shaft 7.

Next, the operation of the actuator will be described.

For example, when the motor 1 starts rotating in a fixed direction, the gear 5 starts rotating in the direction indicated by the arrow A in the figure via the pinion 4.

At this time, when the gear 5 starts to rotate, the positional relationship between the gear 5 and the inner screw member 6 is as shown in FIG. 3 (A).

Therefore, when the gear 5 starts to rotate, the gear 5 rotates by θ along the outer periphery of the inner screw member 6, and then the convex portion 5c of the gear 5 is moved to the inner screw member 6 as shown in FIG. 3B. When the inner screw member 6 collides with the convex portion 6b of the gear 6, and the convex portion 5c of the gear 5 presses the convex portion 6b of the inner screw member 6, the inner screw member 6 starts rotating in synchronization with the rotation of the gear 5.

When the inner screw member 6 starts rotating, the inner screw member 6 is screwed into the inner screw member 6. Since the output shaft 7 is prevented from rotating by the guide pin 8, the output shaft 7 linearly moves (raises) in the upward direction (arrow A ₁ direction).

When the output shaft 7 is linearly moved downward (direction of arrow A ₂ ), the motor 1 is rotated in the opposite direction.

When the motor 1 is rotated in the reverse direction, the gear 5 is rotated in the reverse direction via the pinion 4. After the gear 5 rotates by θ, the convex portion 5c collides with the convex portion 6b of the inner screw member 6. The inner screw member 6 is started by the impact force when the convex portion 5c collides with the convex portion 6b, and starts to rotate.

When the inner screw member 6 rotates in the opposite direction, the output shaft 7 linearly moves downward (in the direction of arrow A ₂ ) (downward).

As described above, when the output shaft 7 is forcibly stopped by the guide pin 8, the tightening torque applied to the inner screw member 6 and the output shaft 7 by the inertial force of the motor is equal to or more than the maximum torque of the motor. Is configured to rotate the gear 5 by θ without load, and a torque more than the loosening torque is obtained by the impact force when the protrusion 5c of the gear 5 collides with the protrusion 6b of the inner screw member 6. The inner screw member 6 and the output shaft 7 can be unfastened, and the inner screw member 6 can be rotationally activated to linearly move the output shaft 7.

The required loosening torque can be obtained relatively easily by the gear portion having the convex portion on the inner periphery and the inner screw member having the convex portion on the outer periphery, and therefore, the stop structure of the output shaft can be inexpensively and reliably provided. It is possible to realize an actuator having the same.

[0034]

[Effect of the device]

 As described above, according to the present invention, since the gear portion is rotated at a predetermined angle with no load and then collides with the female screw member to start the rotation of the female screw member, a torque larger than the torque of the motor is generated. Even if the internal thread member and the output shaft are tightened, the internal thread member can be reliably started in rotation with a relatively simple structure, and there is no need to upsize the motor or use the ball screw method. It has features such as realizing an actuator with a stop structure for the output shaft at a low cost.

[Brief description of drawings]

FIG. 1 is a sectional view of an embodiment of the present invention.

FIG. 2 is a sectional view of an embodiment of the present invention.

FIG. 3 is a diagram for explaining the operation of the embodiment of the present invention.

[Explanation of symbols]

 1 Motor 4 Pinion 5 Gear Member 6 Inner Screw Member 7 Output Shaft

Claims (1)

[Scope of utility model registration request] 1. An actuator for linearly reciprocating the output shaft by rotating the screw part for screwing the male screw part formed on the output shaft according to the rotation of the motor, wherein the female screw part It has a screw member formed on the circumference and has a first convex portion formed on the outer periphery, and a second convex portion that engages with the first convex portion formed on the female screw member on the inner periphery. An actuator configured to be rotatable by a predetermined angle with respect to the female screw member, the gear portion being engaged with the motor and rotating according to the rotation of the motor.