JPH0578174U - Motor actuator - Google Patents

Abstract

(57) [Abstract] [Purpose] An object of the present invention is to provide a motor actuator that can be manufactured at low cost and attached to a motor shaft to obtain high durability, even if the worm gear has a large lead angle and a small diameter. And A motor 3, a control circuit for controlling a stop position of the motor 3, and a reduction gear 4 for decelerating and transmitting the rotation of the motor 3 to an output shaft 6 for driving a driven body. And a worm gear 9 attached to the rotating shaft 3a of the motor 3 so as to mesh with the reduction gear 4, the worm gear 9 is
It was formed by a plastic molded product in which the metal shaft 10 was inserted.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a motor actuator for driving a driven body and stopping it at a predetermined rotation position.

[0002]

[Prior Art]

 In this type of motor actuator, the rotation of the motor is reduced by the reduction gear and transmitted to the output shaft. However, if there is a gear that rotates at high speed, it becomes a noise source, so it is desirable to have a large reduction ratio between the rotating shaft of the motor and the reduction gear.

Therefore, a worm gear is attached to the rotary shaft of the motor, and the first gear of the reduction gear is used as a worm wheel to mesh with each other so that large deceleration is performed there. In particular, noise is likely to be a problem in motor actuators used to drive automobile air-conditioning doors, so a worm gear is always attached to the rotary shaft of the motor.

[0004] Such a worm gear was made by cutting metal in the past, but since it is too expensive to manufacture, it has recently been formed by a plastic molded product.

[0005]

[Problems to be solved by the device]

 However, worm gears have the drawback of lower transmission efficiency than general gears, and it is necessary to eliminate this problem as much as possible.

In order to improve the transmission efficiency, it is sufficient to increase the lead angle of the worm gear. However, if the advance angle is simply increased, the reduction ratio between the worm wheel and the worm wheel will decrease, and noise will start to be generated.

Therefore, in order to increase the reduction ratio and increase the advance angle, there is no other choice but to reduce the diameter of the worm gear. However, when the diameter of the worm gear becomes smaller, the worm gear formed by the plastic molded product easily breaks, causing a problem in durability. However, if the metal is formed by cutting as before, the manufacturing cost will be too high.

Therefore, an object of the present invention is to provide a motor actuator in which even a worm gear having a large lead angle and a small diameter can be manufactured at low cost and attached to a motor shaft to obtain high durability. And

[0009]

[Means for Solving the Problems]

 In order to achieve the above object, the motor actuator of the present invention includes a motor, a control circuit for controlling the stop position of the motor, and a rotation of the motor on an output shaft for driving a driven body. In a motor actuator that has a reduction gear for decelerating and transmitting, and a worm gear is attached to the rotary shaft of the motor so as to mesh with the reduction gear, a plastic molded product in which the worm gear is inserted through a metal shaft. It is characterized by being formed by.

[0010]

[Action]

 The worm gear is formed by inserting a metal shaft into a plastic mold and retains sufficient strength even if the worm gear has a small diameter.

[0011]

【Example】

 An embodiment will be described with reference to the drawings. 1 and 2 are plan and front cross-sectional views of a motor actuator, each schematically shown to some extent for ease of understanding.

In the upper and lower housings 1 and 2, there are provided a motor 3 as a power source, a reduction gear group 4 for decelerating and transmitting the rotation of the motor 3, and a control circuit for controlling a stop position of the motor. A printed circuit board 5 and the like, which are partially wired, are provided.

Reference numerals 6 and 7 denote an output shaft for driving a driven body (not shown) and an output arm fixed to the output shaft. The output shaft 6 is formed integrally with the final gear 4 a of the reduction gear group 4. There is. A link or the like for connecting to the driven body is connected to the output arm 7.

Reference numeral 8 denotes a conductive brush attached to the back surface of the final gear 4 a, which contacts a conductive pattern (not shown) formed on the printed circuit board 5 to generate a stop signal for the motor 3. While rotating with the final gear 4a.

A worm gear 9 is press-fitted and attached to the rotary shaft 3 a of the motor 3, and the first gear 4 b of the reduction gear group 4 is a worm wheel that meshes with the worm gear 9.

The worm gear 9 is formed of a plastic molded product, and the shaft portion of the portion where the gear is formed has a metal shaft such as a stainless rod as shown in FIG. 10 is inserted and integrally molded.

Therefore, in order to maximize the transmission efficiency, the lead angle of the worm gear 9 is increased, and in order to increase the reduction ratio with the worm wheel 4b, the pitch circle diameter of the worm gear 9 is made as small as possible. Even if 9 is formed as thin as possible, the strength of the worm gear 9 is maintained by the metal shaft 10.

Therefore, even when the worm gear 9 is press-fitted into the output shaft 3a of the motor 3 or in an actual use condition in which a load from the driven body is applied, the worm gear 9 has strength sufficient to prevent damage.

The shaft 10 is inserted into the worm gear 9 so as to project from the tip of the worm gear 9, and the projecting portion of the shaft 10 is rotatably fitted in a bearing hole 11 formed in the lower housing 2. And is supported.

Accordingly, a considerable portion of the force applied to the worm gear 9 during rotation is received by the shaft 10 and the bearing hole 11 portion, and a large force is not locally applied to the worm gear 9.

The present invention is not limited to the above-described embodiment. For example, after the worm gear 9 is molded by a plastic molded product having a hole in the central shaft portion, the metal shaft 10 is provided in the hole. You may pass it.

[0022]

[Effect of the device]

 According to the motor actuator of the present invention, since the worm gear attached to the rotary shaft of the motor is formed by the plastic molded product having the metal shaft inserted, it can be manufactured at low cost and the worm gear can be advanced. It has an excellent effect that it can obtain high durability even if it is formed with a large angle and a small diameter.

[Brief description of drawings]

FIG. 1 is a plan sectional view of an example.

FIG. 2 is a front sectional view of an example.

[Explanation of symbols]

 3 Motor 3a Rotating shaft 4 Reduction gear group 4b Worm wheel 6 Output shaft 9 Worm gear 10 Metal shaft

Claims (1)

[Scope of utility model registration request] 1. A motor, a control circuit for controlling a stop position of the motor, and a reduction gear for decelerating and transmitting the rotation of the motor to an output shaft for driving a driven body. Then, in a motor actuator in which a worm gear is attached to a rotating shaft of the motor so as to mesh with the reduction gear, the worm gear is formed by a plastic molded product having a metal shaft inserted therethrough.