JPH038077Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a stator of a rotary actuator that rotates a rotor magnet by an arbitrary fixed angle by excitation of a coil.

(Prior Art) Conventionally, for example, the rotary actuator disclosed in Patent Application Publication No. 1983-83574 is
As shown in the figure, it has a two-phase, four-pole pulse motor configuration. The rotor magnet 51 is magnetized to N and S poles, and has pole teeth 52 arranged along its circumference.
A, 52B generate magnetic poles when the coil 53 is excited, and the pole teeth 54A, 54B,
A magnetic pole is generated when the coil 55 is energized.
A switch 56 is connected to the coil 53, and a switch 57 is connected to the coil 54 to turn on and off the excitation current applied to the coils 53 and 54 from the outside.
Turn off.

In FIG. 9, pole teeth 52A, 52B, 54
A and 54B are shown schematically, but they are shown in specific shapes in FIGS. 10 and 11. The shape of the pole teeth shown in FIG. 10 is wide at the base end and narrows toward the tip, and the pole teeth 52A and 52B are shaped like one stator formed in a cup shape. 52 with a pitch of 180 degrees, and the pole teeth 54A and 54
B is formed on the other stator 54 at a pitch of 180 degrees. By meshing the stator 52 and the stator 54, the pole teeth 52A, 52B, 54
A, 54B are P, 54B in FIG. 9 as shown in FIG.
They are arranged at equal intervals at 90 degree pitches corresponding to Q, R, and S. Note that FIG. 11 shows an example in which the shape of the pole teeth is rectangular, and the pole teeth 52A, 52B, 5
4A and 54B are arranged at equal intervals of 90 degrees as in FIG.

With the excitation power source 61 and the common terminal W of the coils 53 and 55 connected, turn on the switches 56 and 57.
By turning ON, N poles are generated in the pole teeth 52A and 54B, S poles are generated in the pole teeth 52B and 54A, and torque is generated between the rotor magnet 51 and the rotor rotates 45 degrees clockwise from the figure. It will be balanced and stop at that position. By changing the current ratio of the resistors 58 and 59, the rotor magnet 51 rotates clockwise or counterclockwise and stops at a position where the torque is balanced. (For example, coil 53
If the current in the coil 55 has a larger current ratio than the current in the coil 55, the current in the coil 55 will rotate in a counterclockwise direction. ) (Problem to be solved by the invention) When the excitation current applied to the coils 53 and 55 is cut off by turning off the switches 56 and 57,
The rotor magnet 51 is restored to a stable point by the detent torque, but as shown in the detent torque characteristic in Fig. 12, there are two stable points within the 90 degree control range, for example, point P and point Q. do. Therefore,
When the excitation currents of the coils 53 and 55 are cut off simultaneously, it is unclear whether the rotor magnet 51 will be stabilized at either the P point or the Q point. Therefore, for example, if you want to make the point P a stable point, the timing for turning off the switch 57 can be set by changing the timing of turning off the switch 57.
By delaying the timing of turning OFF, magnetic poles are generated in the pole teeth 54A and 54B,
It is necessary to turn off the switch 57 while the rotor magnet 51 is stably stopped at point P. However, at this timing, switches 56 and 57
A separate timing circuit is required to turn off the power supply, and if the circuit is configured to immediately shut off the control power supply when an electrical abnormality such as a disconnection is detected, the timing circuit will not function properly. Therefore, due to the above-mentioned reason, it is no longer possible to define the stable point of the rotor magnet 51, and an electric circuit is required to determine which point is the control start point when returning from an abnormality.
There was a problem of complicating the entire electrical circuit.

Therefore, in order to solve the above problems, the present invention makes the pole teeth arranged on the stator unevenly spaced, and uses the very small space as a stable point to which the rotor magnet returns with the restoring force due to the detent torque. The technical problem to be solved is to determine the point at one location.

(Means for solving the problem) The technical means for solving the above problem is to mesh and oppose cup-shaped magnetic members of the same shape, each having a plurality of pole teeth formed on the circumference of the inner diameter surface at different intervals. The cup-shaped stator is wound twice in the same direction in the space between the outer diameter surface and the inner diameter surface of the cup-shaped stator, and the end of one winding is connected to the beginning end of the other winding. This connection end is used as a common terminal, and the winding start end on one side and the winding end end on the other side are used as excitation control terminals, and an excitation current is passed between the excitation control terminal and the common terminal. a coil that generates magnetic poles in the plurality of pole teeth when the stator is rotated, and a rotor magnet that is rotatably attached to the inner diameter of the cup-shaped stator and that is alternately magnetized with north and south poles in the radial direction. In the rotary actuator, when magnetic poles are generated in the pole teeth, the distance between opposing end faces of adjacent different poles is made small, and each end face is formed parallel to the axial direction of the rotor magnet. At the same time, the pole teeth are formed so that the distance between opposing end surfaces of adjacent same poles is larger than the distance between the opposite end surfaces, and the tip of each of the pole teeth is formed into a tip-drawn shape.

(Operation) When an excitation current is applied to the coil provided inside the cup-shaped stator, magnetic poles are generated in the pole teeth formed in the cup-shaped stator, and torque is generated between the stator and the rotor magnet. The magnet rotates clockwise or counterclockwise by a rotation angle depending on the degree of magnetic force generated by the pole teeth. When the excitation current of the coil is cut off in this state, the rotor magnet returns to a stable point and rotates due to the detent torque, but the rotor magnet is a small magnet whose magnetized poles have good transmission efficiency for the lines of magnetic force. In order to restore rotation with the center of the adjacent pole teeth having the same end face distance as a stable point, there is one stable point in the ±90 degree rotation range of the rotor magnet, which always returns the rotor magnet to the same position.

(Example) Next, an example of the present invention will be described with reference to FIGS. 1 to 4.

FIG. 1 shows a cross section of a rotary actuator 1, in which a cup-shaped stator 6 is provided with a coil 5 with an intermediate tap wound around a bobbin 4 in a space formed by a housing 2 and a cover 3. A rotor magnet 8 integrated with a shaft 7 is mounted on the inner circumference of the stator 6 and supported by bearings 9 and 10.

FIG. 2 is an exploded structural view of the rotary actuator 1 shown in FIG. 1. Among these, stator 6
is constructed by meshing and opposing stator members 11 and 12 of the same shape, and stator member 11 is formed with pole teeth 11A and 11B, and stator member 12 is formed with pole teeth 12A and 12B. Pole teeth 11A, 11B and pole teeth 12A, 12
B is formed so that when the stator members 11 and 12 are meshed with each other, they are spaced at irregular intervals.

FIGS. 3 and 4 show the pole teeth 11A, 11
This is a developed diagram showing examples of the shapes of B, 12A, and 12B. Among the pole teeth shown in FIG. 3, the spacing between the pole teeth of different poles, in this case the spacing a between the pole teeth 11A and 12A and between the pole teeth 11B and 12B, is narrowed, and the spacing between the pole teeth of the same polarity is narrowed. In this case, pole teeth 11A and 11B
In addition to widening the gap b between the pole teeth 12A and 12B, the opposing pole tooth end surfaces of different poles are
Both of the pole teeth shown in the figure and FIG.
In the case of FIG. 4, they are aligned with the axial direction of the rotor magnet 8. That is, the feature is that the distance between the opposing pole tooth end faces of different poles is made very small, and the end faces are always aligned in the axial direction of the rotor magnet 8.

Next, the operation of this embodiment will be explained.

The rotor magnet 8 is disposed on the inner periphery of the cup-shaped stator 6 having pole teeth as shown in FIG. 3 or 4.
Due to its own magnetic force, a force that tries to return to a stable point, detent torque, is generated. This state is shown in the detent torque characteristic diagram shown in FIG. As shown in the detent torque characteristic diagram shown in FIG. 5, the detent torque of the rotor magnet 8 is 0.
The stable point is the point where the pole tooth spacing a
The point A is the center of the adjacent pole tooth. The reason for this is that the nature of the magnetic lines of force generated from the rotor magnet 8 is such that the pole tooth spacing a is slightly smaller than the wide pole tooth spacing b.
This is because it is easier to pass through. Therefore, in the case of this embodiment, when the control range is set to ±90 degrees, from the two stable points P and Q of the detent torque characteristic diagram shown in FIG. 12 of the conventional rotary actuator, The stable point can be limited to one point, A point.

Furthermore, although the magnitude of the detent torque differs depending on the shape of the pole teeth, the detent torque is larger in the shape of the pole teeth as shown in Figure 3 than in the shape of the pole teeth as shown in Figure 4. Confirmed by experiment. This state is shown by solid lines and broken lines in FIG. The solid line shows the detent torque in the case of the pole tooth shape shown in FIG. 3, and the broken line shows the detent torque in the case of the pole tooth shape shown in FIG. The reason why the detent torque in the case of the pole tooth shape shown in Fig. 3 is larger than the detent torque in the case of the pole tooth shape shown in Fig. 4 is because magnetic force tends to concentrate by constricting the tips of the pole teeth. Presumed.

Next, the basic operation of the rotary actuator 1 of this embodiment will be explained with reference to FIGS. 6 to 8.

FIG. 6 schematically shows the structure of the rotary actuator 1 shown in FIGS. 1 and 2. As shown in FIG. When the coil 5 is supplied with an excitation current from an external excitation power source 60, the pole teeth 11A, 11B,
Magnetic poles are generated in 12A and 12B, torque is generated between the rotor magnets 8, and the rotor magnets 8
rotates clockwise or counterclockwise. Switch SW1 and switch SW2 determine the direction of the excitation current flowing through the coil 5. By turning on switch SW1 or switch SW2, the magnetic poles generated in the pole teeth change, and the rotation direction of the rotor magnet 8 changes. It is determined.

Incidentally, the coil 5 for exciting the stator 6
is wound around one bobbin 4 fitted in the space between the outer diameter part and the inner diameter part of a pair of cup-shaped stators 6, and the winding method is as shown in FIG.
Two coils 5 are wound simultaneously and in the same direction, the winding start end of one coil and the winding end end of the other coil are connected, and this is connected to the intermediate tap lead wire as a common wire, and one of the above coils is connected to the lead wire for the intermediate tap. The winding end of one coil and the winding start end of the other coil are connected to each switch SW1,
It is connected to an excitation power source (battery) 60 via SW2. Therefore, the schematic magnetic circuit shown in FIG. 6 is equivalent to the magnetic circuit of the rotary actuator having the configuration shown in FIG.

When both switches SW1 and SW2 are OFF, N
The rotor magnet 8, which is magnetized to the pole and the south pole, is stopped at the position shown in FIG. 6 by the detent torque.

Next, switch SW1 is ON and switch SW2 is ON.
In the case of OFF, as shown in Fig. 7, the pole tooth 11A
Electromagnetic force Ni is generated in and 11B, and the pole tooth 12A
When electromagnetic force Si is generated in and 12B, clockwise torque is generated between it and the rotor magnet 8,
It rotates to a point at an angle θ that is in balance with the detent torque and stops.

This time, switch SW1 is OFF, switch SW
2 is turned on, electromagnetic force Si is generated in the pole teeth 11A and 11B, as shown in Fig. 8, and the pole tooth 1
Electromagnetic force Ni is generated between 2A and 12B, and a counterclockwise torque is generated between them and the rotor magnet 8. As a result, the rotor magnet 8 rotates to a point at an angle -θ where it is in equilibrium with the detent torque, and then stops.

The rotor magnet 8 is at the angle θ, or
After rotating to -θ and stopping, turn the switch.
When SW1 and switch SW2 are turned OFF, the magnetic pole generated by the pole teeth disappears, only detent torque is generated, and the rotor magnet 8 returns to the state shown in FIG. 6.

For example, by attaching a valve or the like to the shaft 7 of the rotor magnet 8, and setting the valve so that the opening degree of the valve is on the safe side when the rotor magnet 8 returns to a stable point only by the detent torque. If an abnormality occurs in the electric circuit, the valve can be returned to a safe state even if the power is turned off.

(Effects of the invention) As described above, according to the invention, it is possible to determine one stable point within the control angle range of ±90 degrees of the rotary actuator to which the detent torque of the rotor magnet returns. This has the effect of allowing fail-safe control without adding a safety circuit for electrical control.

[Brief explanation of the drawing]

Fig. 1 is a sectional view showing the configuration of an embodiment of the present invention, Fig. 2 is an exploded view thereof, Figs. 3 and 4 are diagrams of the shape of the pole teeth, and Figs. 5 to 8 are the functions of the embodiment. Explanatory diagrams, FIGS. 9 to 12 are explanatory diagrams showing conventional techniques. 1...Rotary actuator, 2...Housing, 3...Cover, 4...Bobbin, 5...Coil, 6...Stator, 7...Shaft, 8...Rotor magnet, 9, 10... Bearing, 11A, 1
1B, 12A, 12B...Polar teeth.

Claims (1)

[Scope of utility model registration request] By facing two cup-shaped magnetic members having the same shape and having a plurality of pole teeth formed on the circumference of the inner diameter surface at different intervals, the pole teeth of the respective cup-shaped magnetic members are opposed to each other in a non-contact state. a stator positioned so as to mesh with each other and formed so that the spacing between opposing pole teeth is considerably smaller than the spacing between pole teeth of the same cup-shaped magnetic member; and an outer diameter portion and an inner diameter portion of the stator. A single bobbin fitted in the space between the two is wound in a double manner in the same direction, and the winding start end of one of the double windings is connected to the winding end of the other winding end, This is connected as a common wire to the lead wire for the intermediate tap, and the end of one winding and the start end of the other winding are respectively connected to the lead wire for supplying exciting current to the coil, and the stator. In a rotary actuator, the rotor magnet is rotatably mounted on the inner diameter portion via a shaft and has a rotor magnet magnetized alternately in the radial direction with N poles and S poles on the outer circumferential surface. The opposing end surfaces of the teeth are formed to be parallel to the axial direction of the rotor magnet, while the opposite end surfaces of the opposing pole teeth are formed so that the opposite end surfaces of the opposing pole teeth become closer to the tip. A stator for a rotary actuator, characterized in that the stator is formed into a tapered shape so that the stator becomes thinner.