JP2555586B2 - Rotary Actuator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Object of the Invention (Field of Industrial Use) The present invention electrically controls the opening degree of a valve such as a damping force control valve of an absorber of an automobile or the like in several steps within a predetermined range. It is related to the rotary actuator.

(Prior Art) Conventionally, as a rotary actuator for electrically controlling the valve opening of this kind, a 3-position rotary actuator as shown in FIG. 4 has been used.

FIG. 4 is an exploded perspective view of the 3-position rotary actuator, and FIGS. 5a to 5c are sectional views of the 3-position rotary actuator.

Here, the stator is formed by winding the winding wire 2 around the salient pole 6 of the stator core 1 a predetermined number of times, and the rotor is composed of the rotor core 4 of the shaft 3 and the magnet 5.

In FIGS. 5a to 5c, the salient pole 6a of the stator core 1 has N
When the windings 2a and 2b are energized so that the S pole is generated in the pole and the salient pole 6b, the magnet 5a and the salient pole 6b, and the magnet 5b and the salient pole 6a.
And the magnet 5a and the salient pole 6a and the magnet 5b and the salient pole 6b attract each other, and the rotor rotates to a position where the lever 8 hits the stopper 7a (Fig. 5a). Similarly, the windings 2a, 2 are arranged so that the salient pole 6a has an S pole and the salient pole 6b has an N pole.
When electricity is supplied to b, the rotor rotates until the lever 8 hits the stopper 7b (Fig. 5b). And the salient pole 6c is the north pole,
When the windings 2c and 2d are energized so that the S pole is generated on the salient pole 6d,
The rotor stops at a position where the lever 8 is located between the stopper 7a and the stopper 7b (Fig. 5c).

As described above, in the three-position rotary actuator, the stop position is obtained in three stages by energizing the winding 2.

(Problems to be solved by the invention) However, if any force is applied from the outside to the actuator when the energization to the windings 2a, 2b, 2c, 2d is cut off in any of the above conditions, the holding to the rotor Because the power does not work,
The rotor could rotate freely, and the valve could move unexpectedly.

In order to eliminate this drawback, it is possible to energize the winding 2 constantly.

However, if the winding 2 is constantly energized, the resistance of the winding 2 raises the temperature of the winding 2 and the efficiency deteriorates.

It is also conceivable to add a mechanism for holding down the rotor at the rotor stop position, but in this case, a mechanism such as a solenoid or clutch is required to hold down the rotor, which is a problem in terms of shape and cost. .

Therefore, it is an object of the present invention to provide a rotary actuator with a simple structure so that the rotor can be held in the stop position even when the winding is de-energized.

[Structure of Invention]

(Means for Solving Problems) A rotary actuator according to the present invention includes a magnet having two poles and having a predetermined arc rate, a shaft,
A rotor having a rotor core connecting the magnet and the shaft, rotating about the shaft, a salient pole arranged along the circumference of the rotation locus of the magnet, and a salient pole having the same width as the field width of the magnet, and a salient pole. A stator having a winding wound a predetermined number of times, and first and second stoppers for restricting the rotation angle of the rotor within a predetermined range.
A pair of first salient poles facing each other across the rotor, and a first
The rotor is composed of a pair of first salient poles which are alternately arranged with salient poles and which face each other with the rotor interposed therebetween. The rotor is restricted by a first position where a magnet faces only the second salient pole and a first stopper, and The magnet is regulated by a second position and a second stopper that face the first and second salient poles, and the magnet can stop at a third position that faces the first and second salient poles. The second salient pole has an arc rate equal to that of the magnet, and the second salient pole has an arc rate greater than that of the magnet.

(Operation) According to the present invention, in the three-position rotary actuator in which the first and second salient poles are alternately arranged,
Makes the arc rate of the first salient pole equal to the arc rate of the magnet and
Since we made the salient pole loneliness larger than the magnet loneliness,
When the rotor is stopped by the stopper at the second or third position (the position where the magnet faces the first and second salient poles), when the winding is de-energized, the rotor will move from that position due to some force. If it is slightly displaced toward the first position,
The gap between the second salient pole and the magnet is larger than the gap between the first salient pole and the magnet. As a result, the amount of magnetic flux between the second salient pole and the magnet becomes smaller than the amount of magnetic flux between the first salient pole and the magnet, whereby the rotor receives a force toward the second or third position, and the second or third Returned to position 3. Thus, the rotor can be held at the second or third position when the winding is de-energized while the magnet is stopped at the second or third position facing the first and second salient poles. .

(Practical example) Hereinafter, an example showing a specific example of the rotary actuator of the present invention will be described. The same members as those of the conventional device described above are designated by the same reference numerals.

FIG. 1 and FIGS. 2a to 2d show a three-position rotary actuator.

Here, in the stator, the winding 2 is wound around the salient pole 6 of the stator core 1 a predetermined number of times, and the rotor is composed of the shaft 3, the rotor core 4, and the magnet 5. Further, the rotor is provided with a lever 8 for restricting the rotation range by the stopper 7. The lever 8 and the stopper 7 rotate the rotor in the range from -π / 3 to π / 3 (Fig. 2a).

The stator core 1 has a salient pole 6c so that the amount of magnetic flux becomes maximum at the rotor stop position in the gear with the magnet 5.
And 6d are higher than magnet 5's
Both ends of 6c and 6d are set farther from the magnet 5 than the center (Fig. 2c). FIG. 3 shows the relationship between the rotation angle of the rotor and the amount of magnetic flux when the winding is not energized. Salient pole 6c
The magnetic flux amount increases when the distance between the magnet and the magnet 5a is short, and the magnetic flux amount decreases when the distance is far. Here, the curve of the amount of magnetic flux has an apex at the positions of −π / 3,0, π / 3.

The operation of the embodiment constructed as described above will be described with reference to FIGS.

1) When the windings 2a, 2b are energized so that the salient pole 6a of the status core 1 has an N pole and the salient pole 6b has an S pole, the rotor rotates until the lever 8 hits the stopper 7a (Fig. 2a).

2) Winding 2 so that S pole is formed on salient pole 6a and N pole is formed on salient pole 6b
When a and 2b are energized, the rotor rotates until the lever 8 hits the stopper 7b (Fig. 2b).

3) Winding 2 so that N pole is formed on salient pole 6c and S pole is formed on salient pole 6d
When c and 2d are energized, the rotor stops at the lever 8 at a position intermediate between the stoppers 7a and 7b (Fig. 2c).

When the power supply to the winding is cut off in the state of 1), when the lever 8 is slightly separated from the stopper 7a (Fig. 2d), the magnet 5a magnetized to the S pole has a narrow gap with the salient pole 6a, Salient pole
Since the distance from 6c is wide, the rotor receives a force in the direction in which the lever 8 approaches the stopper 7a due to the difference in the amount of magnetic flux. Due to this force, the rotor is fixed at a position where the lever 8 contacts the stopper 7a.

When the winding is de-energized in the state of 2), the rotor receives a force in the direction in which the lever 8 approaches the stopper 7b when the lever 8 is slightly separated from the stopper 7b, as in the case of 1). . Due to this force, the rotor is fixed at a position where the lever 8 contacts the stopper 7b.

Even when the winding is de-energized in the state of 3), similarly to 1), when the lever 8 is slightly separated from the intermediate position between the stopper 7a and the stopper 7b, the lever 8 is rotated by the rotor due to the difference in the amount of magnetic flux. It receives a force in the direction of an intermediate position between the stoppers 7a and 7b. Due to this force, the lever 8 is fixed to the rotor at an intermediate position between the stopper 7a and the stopper 7b.

In this embodiment, an example of a three-position rotary actuator is shown, but the present invention can be implemented with a multi-position of three positions or more.

〔The invention's effect〕

As described above, according to the present invention, the rotor can be held at the stop position even when some external force is applied in the state where the power supply is cut off.

Since this can be done only by changing the shape of the stator core, the appearance of the rotary actuator does not change and the cost does not increase.

Further, in the case of the embodiment, the magnet 5a has salient poles 6a and 6c.
Or, when it comes between the salient poles 6b and 6c, the magnetic flux tends to move to either side, so −π / 3 to 0, 0 to −π / 3,
High torque can be obtained by any movement from π / 3 to 0 and 0 to π / 3, and the response speed can be increased.

[Brief description of drawings]

FIG. 1 is a sectional view of an embodiment of the rotary actuator of the present invention, and FIGS. 2a to 2d are plan views showing the operating states of the embodiment of the rotary actuator of the present invention. FIG. 3 shows the relationship between the rotation angle of the rotor and the amount of magnetic flux in the embodiment of the rotary actuator of the present invention. FIG. 4 is an exploded perspective view of a conventional rotary actuator, and FIGS. 5a to 5c are plan views showing an operation state of an embodiment of the conventional rotary actuator. 1 ... Stator core, 2 ... Winding, 3 ... Shaft, 4 ... Rotor core, 5 ... Magnet, 6a, 6b ... Salient pole (1st salient pole), 6c, 6d ...
… Salient pole (second salient pole), 7a …… Stopper (first stopper), 7b …… Stopper (second stopper),

Claims (1)

(57) [Claims] 1. A rotor having a magnet having two poles and having a predetermined arc rate, a shaft, and a rotor core connecting the magnet and the shaft, the rotor rotating about the shaft. A stator having salient poles arranged along the circumference of the rotation locus of the magnet and having a width equal to the magnetic field width of the magnet, and a winding wound around the salient pole a predetermined number of times, and a rotation angle of the rotor. A first and a second stopper for restricting a predetermined range, wherein the salient poles are arranged alternately with the pair of first salient poles and the first salient poles that face each other with the rotor in between. The rotor includes a pair of second salient poles that face each other with the rotor sandwiched therebetween. The rotor has a first position in which the magnet faces only the second salient pole, and the magnet is regulated by the first stopper. A second position facing the first and second salient poles and the magnet can be stopped at a third position restricted by the second stopper and facing the first and second salient poles. However, the three-position rotary actuator is characterized in that it has an arc rate equal to that of the magnet, and the second salient pole has an arc rate greater than that of the magnet.