JPH075607Y2 - Electromagnetic actuator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to an electromagnet actuator using an electromagnet as a drive source.

[Prior Art] Electromagnetic actuators are used in various control devices. For example, in an electronic governor (speed regulator) for an internal combustion engine, an electromagnet type actuator is used as a means for operating a control rack (fuel supply amount adjusting means) of a fuel injection pump, and the actual rotation speed and command speed of the engine are By supplying a drive current to the actuator so as to make the deviation of 0 be zero, the amount of fuel supplied to the internal combustion engine is adjusted so that the rotational speed of the engine approaches the support speed.

As an example of the electromagnet type actuator, the actuator previously proposed by the applicant is shown in FIG. In FIG. 3, 1 is a frame, 2 is a mover rotatably supported by the frame 1 via a shaft 3, and 4 is a stator obtained by winding an exciting coil 6 around a stator core 5. The mover 2 has three comb-teeth-shaped movable magnetic pole portions 2a to 2c having cylindrical magnetic pole surfaces 2a1 to 2c1, and the stator core 5 has a cylindrical shape corresponding to the movable magnetic pole portions 2a to 2c, respectively. It has fixed magnetic pole portions 5a to 5c having planar magnetic pole surfaces. The free terminal of the mover 2 is provided with a protrusion 2d, and the rotation range of the mover is set between the first position and the second position by contact between the protrusion and the stopper portions 1a and 1b provided on the frame. Regulated in between. In FIG. 3, the mover 2 is in the first position, and when the exciting coil 6 is excited in this state, the magnetic pole portion 2a of the mover is shown.
Through 2c are attracted to the magnetic pole portions 5a through 5c of the stator, respectively, and the mover rotates counterclockwise in the drawing. When the mover reaches the second position, the protrusion 2d comes into contact with the stopper portion 1b and the mover stops.

The mover 2 is biased toward the first position by a return spring 7 composed of a compression spring arranged between the free end of the mover 2 and the frame, and when the exciting coil 6 is in the non-excited state, the return spring 7 is returned. The mover 2 returns to the first position by the biasing force of 7.

A link 9 is connected to the mover 2 via a pin 8, and the link 9 is connected to a load (not shown).

[Problems to be Solved by the Invention] In the above actuator, the position of the mover 2 is a rotation generated in the mover by an electromagnetic force acting between the fixed magnetic pole part and the movable magnetic pole part when the exciting coil 6 is excited. It is determined by the balance between the torque and the torque of the return spring 7. The torque generated at this balance point is zero, and in order to change the position of the mover by changing the balance position, the value of the current flowing through the exciting coil 6 is increased / decreased to produce the rotational torque due to the electromagnetic force. It is necessary to make the difference from the torque due to the return spring larger than the sliding torque of the mover. Therefore, in order to increase the sensitivity of the actuator, it is necessary to reduce the sliding torque of the mover as much as possible.

In the above actuator, the electromagnetic force generated by energizing the exciting coil 6 not only functions to rotate the mover 2 around the rotation shaft 3 toward the second position (counterclockwise), It also functions to reduce the gap between the movable magnetic poles 2a to 2c and the fixed magnetic poles 5a to 5c. Movable magnetic poles 2a to 2c and fixed magnetic poles
The force for reducing the gap between each of 5a to 5c acts in the radial direction of the rotary shaft 3.

As described above, in the conventional actuator, when an electromagnetic force is generated, a force acts in the radial direction of the rotary shaft 3, so that the sliding torque between the rotary shaft 3 and the bearing supporting the rotary shaft 3 increases,
There is a problem that the sensitivity of the actuator is reduced.
Further, in this case, the sliding resistance between the rotary shaft 3 and the bearing becomes large, so that the life of the bearing is shortened.

An object of the present invention is to provide an electromagnet type actuator that reduces the sliding torque of a mover.

[Means for Solving the Problems] An electromagnet-type actuator according to the present invention includes a rotary shaft supported by a frame via a bearing and a plurality of movable magnetic pole parts symmetrically arranged around a central axis of the rotary shaft. A movable core provided with a movable iron core having a movable core and a movable core provided so that the movable core can be rotationally displaced between at least a first position and a second position, and the movable core is symmetrically arranged around a central axis of a rotation shaft. A plurality of return springs that are urged to return the mover to the first position, and a plurality of fixed sides that are symmetrically arranged around the central axis of the rotating shaft in correspondence with the magnetic poles of the mover. A stator having a magnetic pole portion and an exciting coil wound around the stator iron core. When the exciting coil is excited, each fixed magnetic pole portion attracts the corresponding movable magnetic pole portion to move the movable element. To the second position against the biasing force of the return spring. And a stator which is rotationally displaced up to.

The directions of the return springs are set so that the radial components of the forces acting between the rotary shaft and the bearing are substantially canceled by the return springs.

[Operation] As described above, when the movable side magnetic pole portion and the fixed side magnetic pole portion are symmetrically arranged around the central axis of the rotation shaft, the movable side of the force acting on the mover when an electromagnetic force is generated is generated. Components acting in a direction to reduce the gap between the magnetic pole part and the fixed magnetic pole part cancel each other out, so that when an electromagnetic force is generated, a radial force may act between the rotating shaft and the bearing. Absent. Further, as described above, the plurality of return springs are arranged symmetrically, and the directions of the respective return springs are set so that the radial components of the forces acting between the rotating shaft and the bearing by the plurality of return springs substantially cancel each other out. If set, it is possible to prevent a radial force from acting between the rotary shaft and the bearing due to the biasing force of the return spring.

As described above, according to the configuration of the present invention, the electromagnetic force and the biasing force of the return spring prevent a radial force from acting between the rotating shaft and the bearing, thereby reducing the sliding torque of the mover. Therefore, the mover can be displaced by passing a slight current through the exciting coil, and the sensitivity of the actuator can be increased.

Further, since the sliding torque of the mover can be reduced, the life of the bearing can be extended.

[Embodiment] An embodiment of the present invention will be described in detail with reference to the accompanying drawings.

FIGS. 1 and 2 show an embodiment of the present invention. FIG. 1 is a longitudinal sectional view, and FIG. 2 is an internal structure in which the cover of FIG. 1 is removed and the inside is seen from the right side of FIG. It is a figure.

In these figures, 10 is a frame, and a rotating shaft 12 is supported by this frame via a bearing 11. Rotating shaft 12
A movable iron core 13 made of a laminate of steel plates punched into a predetermined shape is fixed to the. The movable iron core 13 has two movable magnetic pole portions 13a, 13a symmetrically arranged (at an interval of 180 degrees) around the central axis of the rotary shaft 12, and the magnetic pole surfaces of the magnetic pole portions 13a, 13b are cylindrical surfaces. Is formed in. The movable iron core 13 and the rotary shaft 10 constitute a movable element 14.

A nut 15 is screwed into a screw provided at one end of the rotating shaft 12, and the rotating shaft 12 and the movable iron core 13 are connected by this nut 15. Collars 16 to 18, a ring 19, a collar 20 and a lever 21 are fitted to the rotating shaft 12, and a nut 22 screwed to a screw provided at the other end of the rotating shaft 12 allows these collar and ring A lever and is fixed to the rotating shaft. Further, the snap ring 23 is fitted in the groove provided in the frame 10,
The movement of the bearing 11 is restricted by this retaining ring.

A stator 26 is attached to the frame 10 with screws 25. The stator 26 includes a movable iron core 13 and a stator iron core 27.
It consists of an exciting coil 28 wound around. The stator core 27 has two fixed magnetic pole portions 27a and 27b which are symmetrically arranged around the central axis of the rotating shaft 11 so as to correspond to the movable magnetic pole portions 13a and 13b, respectively. The magnetic pole surfaces of the magnetic pole portions 27a, 27b are formed in a substantially cylindrical shape, and both fixed side magnetic pole portions 27a, 27b
A predetermined gap is formed between 27b and the movable magnetic pole portions 13a, 13b. When the movable iron core 13 rotates clockwise from the first position shown in FIG. 2, the movable magnetic pole portions 13a, 13b are moved.
The facing areas of the fixed magnetic pole portions 27a and 27b gradually increase, and when the movable iron core 13 rotates approximately 90 degrees, the movable magnetic pole portions 13a and 13b completely face the fixed magnetic pole portions 27a and 27b, respectively. It is like this.

Two pins 29, 29 are provided by penetrating the movable core 13 in the axial direction. These pins are provided symmetrically (with an angular interval of 180 degrees) around the central axis of the rotary shaft 12, and one end 29a of each pin 29 projects from the end surface of the movable iron core 13 on the bearing 11 side. . One end 29a of each pin 29 is the frame 10
By contacting the stopper provided on the
The rotation range of 14 is restricted between the first position shown in FIG. 2 and the second position rotated by 60 degrees clockwise from the first position.

In addition, the pins 30 and 30 are symmetrically arranged around the central axis of the rotary shaft 12 (1
The pins 30, 30 are inserted into holes provided in the stator core 27. Pin 30,30
A groove portion is provided at each of the other ends of the pins 30, and a ring-shaped portion provided at one end and the other end of the return springs 31 and 31 formed of coil springs is provided at the groove portions provided at the other ends of the pins 30 and 30, respectively. It is fitted. The return springs 31, 31 are tension springs extending in parallel to each other, and the return springs 31 constantly urge the mover 14 toward the first position (the side away from the fixed magnetic pole portion).

Frame 10 also has a cord 3 connected to the excitation coil 28
A grommet 34 for fixing 3, 33 and a grommet 35 having an air vent hole 35a are attached. These grommets are fixed in a state of being sandwiched between the frame 10 and the cover 36 fixed to the frame. As shown in FIG. 2, the frame 10 is provided with protrusions 10a, 10a, and these protrusions are provided with mounting holes 10b, 10b.

In the above actuator, when the exciting coil 28 is energized, the stator core 27 is magnetized, so that the movable magnetic pole portion 13
The a and 13b are attracted to the fixed magnetic pole portions 27a and 27b, respectively, and the mover 14 is rotated clockwise in FIG. The position of the mover 14 is determined by the magnetic attraction force of the stator core 27 and the return spring.
It is decided by the balance with 31 urging forces. The magnetic attraction force generated when the exciting coil 28 is excited not only acts to rotate the mover 14, but also creates a gap between the movable magnetic pole portions 13a and 13b and the fixed magnetic pole portions 27a and 27b. It also works to reduce the size. However, in the present invention, the movable magnetic pole portion 13
a and 13b are arranged symmetrically around the central axis of the rotation axis 12,
Similarly, since the magnetic pole portions 27a, 27 are also arranged symmetrically, the magnetic attraction force in the radial direction acting between the magnetic pole portions 13a and 27a (the force to reduce the gap between the magnetic pole portions) and the magnetic pole portions The magnetic attractive forces acting between 13b and 27b cancel each other out. Therefore, the magnetic attraction force does not act in the radial direction between the rotary shaft 12 and the bearing 11, and the sliding torque of the mover can be suppressed to a small value.

Further, in the present invention, the return springs 31, 31 are arranged symmetrically, and the return springs are always deformed linearly with the rotation of the mover and pull the movable iron cores 13 in opposite directions. Radial forces acting between the rotary shaft 12 and the bearing 11 are canceled by each other by 31, 31, and the sliding torque of the mover is reduced.

In the above example, two movable magnetic poles and two fixed magnetic poles are provided, but more magnetic poles are provided around the central axis so as to cancel the radial component of the electromagnetic attraction force. You may make it arrange | position symmetrically. Similarly, more return springs may be provided symmetrically, and the directions of the return springs may be set so that the radial components of the pulling force of the return springs cancel each other out.

[Advantages of the Invention] As described above, according to the present invention, the movable magnetic pole portion and the fixed magnetic pole portion are symmetrically arranged around the central axis of the rotating shaft, whereby the movable magnetic pole portion and the fixed magnetic pole portion are arranged. The radial components of the electromagnetic force that act in the direction of reducing the gap between the magnetic pole portion are canceled out by each other, and the plurality of return springs are symmetrically arranged so that the rotation shaft and the bearing are Since the radial component of the force acting between the rotor and the bearing is substantially canceled out, the radial force is prevented from acting between the rotating shaft and the bearing due to the electromagnetic force and the biasing force of the return spring, and the mover It is possible to reduce the sliding torque. Therefore, the mover can be displaced by passing a small amount of current through the exciting coil, and the sensitivity of the actuator can be increased.

Further, according to the present invention, since the sliding torque of the mover can be reduced, there is an advantage that the life of the bearing can be extended.

BRIEF DESCRIPTION OF THE DRAWINGS FIGS. 1 and 2 show an embodiment of the present invention. FIG. 1 is a longitudinal sectional view, and FIG. 2 is the right side of FIG. FIG. 3 is a sectional view showing an internal structure of the conventional actuator as viewed from the inside. 10 …… frame, 11 …… bearing, 12 …… rotating shaft, 13 …… movable iron core, 13a, 13b …… movable side magnetic pole part, 14 …… movable element, 26
…… Stator, 27 …… Stator core, 27a, 27b …… Fixed side magnetic pole part, 28 …… Excitation coil, 31 …… Return spring.

Claims (1)

[Scope of utility model registration request] 1. A movable core provided with a rotary shaft supported by a frame via a bearing and a movable core having a plurality of movable magnetic pole portions symmetrically arranged around a central axis of the rotary shaft, the movable core being at least a first core. A mover provided so as to be rotationally displaceable between the first position and the second position; and the mover is arranged symmetrically around the central axis of the rotation shaft to return the mover to the first position. A plurality of return springs for urging the stator core, a stator core having a plurality of fixed magnetic pole portions symmetrically arranged around the central axis of the rotating shaft corresponding to the magnetic pole portions of the mover, and An exciting coil wound around the stator core is provided, and when the exciting coil is excited, each fixed magnetic pole portion attracts the corresponding movable magnetic pole portion to make the movable element act as an urging force of the return spring. Stator for rotationally displacing to the second position against The direction of each of the plurality of return springs is set so that the radial components of the forces acting between the rotating shaft and the bearing are substantially canceled by the plurality of return springs. An electromagnet type actuator.