JPH0130865Y2 - - Google Patents

Description

[Detailed explanation of the invention] This invention relates to an electric actuator.
In particular, it relates to improvements in the torque buffering mechanism of the rotor.

Conventionally, electric actuators have been used as torque buffering devices to stop the motor rotor at a constant operating angle, by applying a protrusion on the rotor side to a cushion material such as rubber, or by continuously generating force in the same direction to stop the motor. Mainly used are means for pressing the material into position, and means for applying a load in advance such as a wave washer.

However, the means using the rubber cushion material,
If the weight of the rotor is large or the speed is high, the repulsion cannot be prevented completely, and the reaction may reverse the rotation or damage the stopper. In addition, with means that continuously generate force in the same direction,
It is not possible to provide an internal switch. Further, the load adding means of the corrugated washer causes power loss in normal operation, and is uneconomical.

In addition, the above-mentioned torque buffering means generates a strong collision noise when the rotor is stopped, and measures to prevent noise are required.

This invention was made to solve the above problem, and is effective in reliably preventing the rotor from reversing at the stop position of its operating angle, reducing collision noise, and preventing damage to the stopper member. The object of the present invention is to provide an electric actuator that has the following characteristics and can minimize power loss.

Hereinafter, this invention will be explained in detail based on drawings showing examples thereof.

In Figures 1 to 3, 1 is a cylindrical yoke of a small DC motor, 2 is a field pole, 3 is a rotor,
4 is a rotating shaft, and 5 is a cap-shaped base fitted on one side of the cylindrical yoke 1.

The rotor 3 is operated as shown in FIG. 3 by a control circuit including a conductive plate (not shown) provided on the end surface side of the rotor and a brush (not shown) provided on the base side. The rotation is controlled by an operating angle α. Furthermore, a protrusion 6 protruding in the axial direction is provided on the end surface of the rotor 1 at an eccentric portion thereof for a purpose to be described later.

An annular groove 7 is formed in the inner peripheral surface of the cap-shaped base 5, and a ring-opening spring 8 is fitted into the annular groove 7, and both ends thereof have upright portions 8 bent in the axial direction.
a, 8a, and both upright portions 8a, 8a are set to have an opening angle β smaller than the working angle α of the rotor, as shown in FIG. In addition, the ring opening spring 8
The relationship between the outer diameter d and the inner wall diameter D of the annular groove 7 satisfies D≦d, so that the annular groove 7 can freely rotate within the annular groove.

The cap-shaped base 5 has a bearing portion 9 that can support the rotor rotating shaft 4 when it is combined with the yoke 1, and in this combination, the protrusion 6 on the rotor side is inserted into the cap-shaped base 5. The ring-opening spring 8 is positioned between the upright portions 8a, 8a of the ring-opening spring 8.

In the electric actuator configured as described above, when the rotor 3 rotates through the operating angle α shown in FIG. Before reaching the ring-opening spring 8, one standing portion 8a
, and acts to expand the outer diameter d of the spring 8, so the angular velocity of the rotor 3 decreases due to the increase in frictional resistance between the ring-opening spring 8 and the annular groove 7 that receives it, and the buffer As a result, the rotation of the rotor is effectively prevented from reversing due to the reaction at the stopper, and the generation of collision noise is also reduced. In addition, since the protrusion 6 can move freely over most of the operating angle α, there is almost no power loss.

In the embodiment described above, the ring-opening spring 8 is a wire rod having a circular cross section that is curved into an annular shape.
As shown in FIG. 4, a wave-shaped band plate part 8b is formed in the middle part of the band plate part 8b, so that when the protrusion 6 hits the band plate part 8b, it is easy to bend forward. , the contact friction resistance with the annular groove 7 is increased, so that the buffering function can be strengthened.

5 and 6 are other embodiments of this invention, in which a crank 10 is fixed to the rotating shaft 4 of a rotor 3, and a protrusion 12 slides into a guide slot 11 formed in the crank 10. On the other hand, an elongated guide hole path 13 is formed in the eccentric portion of the inner end surface of the cap-shaped base 5, and the protrusion 12 is inserted into the long groove 13, so that the rotor can move at the above-mentioned operating angle. When rotating, the protrusion 12 is converted into a linear motion by the guiding action of the crank 10 and the guide groove 13, as shown in FIG. ing.

As described above, according to this invention, in an electric actuator in which the rotor of the motor is controlled to rotate at a constant operating angle, the ring-opening spring can freely slide in the circumferential direction inside the cap-shaped base of the motor. The ring-opening ring is fitted into the rotor, and its both ends have an opening angle smaller than the operating angle of the rotor, and are formed into upright parts bent approximately in the axial direction, and the rotor has the ring-opening ring that follows the rotational movement of the rotor. Since the protrusion that moves between the two upright parts of the spring is integrally provided, it prevents repulsion and reverse rotation when the rotor is stopped, reduces collision noise that occurs when the rotor stops, reduces power loss, and reduces the stopper. It is possible to obtain an electric actuator that has an excellent function of preventing damage.

[Brief explanation of the drawing]

Fig. 1 is an exploded perspective view of an electric actuator showing an embodiment of this invention, Fig. 2 is an enlarged sectional view of the main parts of the torque buffer mechanism, Fig. 3 is an explanatory diagram of the torque buffer operation, and Fig. 4 is another open view. Perspective view of ring spring, fifth
The figures are an exploded perspective view of an electric actuator showing another embodiment, FIG. 6 is an enlarged perspective view of the crank part, and FIG.
The figure is an explanatory diagram of torque buffering operation. 1... Motor yoke, 2... Field pole, 3... Rotor, 4... Rotating shaft, 5... Cap-shaped base, 6...
Projection, 7... Annular groove, 8... Ring opening spring, 8
a... Standing part, 9... Bearing part, 10... Crank, 11... Guide slot, 12... Protrusion, 13...
Guide groove.

Claims (1)

[Scope of utility model registration request] In an electric actuator in which the rotor of the motor is controlled to rotate at a constant operating angle, an opening spring is fitted inside the cap-shaped base of the motor so as to be able to freely slide in the circumferential direction, and both ends of the ring-opening spring are attached to the cap-shaped base of the motor. The ring-opening spring has an upright portion bent substantially in the axial direction with a smaller opening angle, and the rotor is integrally provided with a protrusion that moves between the two upright portions of the ring-opening spring following the rotational movement of the rotor. An electric actuator characterized by being provided in.