JP2652479B2 - Vibration type actuator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an actuator in which a mover vibrates in a circumferential direction about a rotation axis. The present invention is applied to, for example, a vibrator for a fatigue test and the like.

[0002]

2. Description of the Related Art A conventional vibration type actuator will be described with reference to FIGS. FIG. 6 is a view for explaining the whole conventional vibration type actuator. FIG. 6 (A) is a schematic front view of the actuator, and FIG. 6 (B) is a schematic side view. In addition, for simplification of the drawings, illustration of parts not directly related to the present invention (bearings of a rotating shaft, brackets for holding the bearings, etc.) is omitted.

As shown in FIG. 6, permanent magnets 12a and 12b for generating a pair of bias magnetic fluxes are fixed inside a yoke 10 for assembling a magnetic circuit. Permanent magnet 12
a pair of stators 14a and 14b are fixed inside a,
Inside the other permanent magnet 12b, a pair of stators 14c,
14d is fixed. That is, the pair of permanent magnets 12
Two pairs of stators are arranged between a and 12b.

[0004] Each of the four stators 14a to 14d has
The coils 16a to 16d are wound, and the stators 14a to 14d are wound.
Space enclosed by d (substantially cylindrical space whose axis is perpendicular to the paper surface)
Is provided with a mover 26 fixed to the shaft 24. An alternating current (for example, a sine wave current) is supplied to the coils 16a to 16d to change the bias magnetic flux in the stator, thereby causing the mover 26 to vibrate in a circumferential direction between, for example, aa ′ and bb ′. Let it. The arrows inside the permanent magnets 12a and 12b indicate the directions of the bias magnetic flux.

[0005] As shown in FIG. 6 (B), a leaf spring 28 is connected to one end of the mover 26. The leaf spring 28 is for returning the movable element 26 having a stable state in the vicinity of aa ′ and bb ′ to the horizontal position shown in FIG. . In order to support the leaf spring 28, a support table 30 having one end fixed to the yoke 10 and a fixture 32 are provided.

FIG. 7 is a perspective view of the mover 26 shown in FIG. 6, and also shows a part of the shaft 24 and the leaf spring 28. The mover 26 has, for example, an outer diameter D = 15 mm and a length H = 40 m.
m, thickness T = 4 mm.

Next, the operation of the conventional vibration type actuator shown in FIG. 6 will be described with reference to FIGS. still,
The amount of magnetic flux of the permanent magnets 12a and 12b is
16d is set to be much larger than the amount of magnetic flux generated.

FIG. 8 is a diagram showing a state where the current flowing through the coils 16a to 16d is set to zero and the mover 26 is stopped at a horizontal position. Therefore, the magnetic force lines 34a to 34 shown by broken lines
d is due to the permanent magnets 12a and 12b. still,
In FIG. 8, the illustration of the shaft 24 is omitted. As described above, the amount of bias magnetic flux generated by the magnets 12a and 12b is sufficiently large, and in the state shown in FIG. 7, the circumferential surface portion of the mover 26 facing the stators 14a to 14d has reached magnetic saturation, or , Near magnetic saturation.

The mover 26 shown in FIG. 8 is in an equilibrium state, but is not in a stable state. In the state shown in FIG.
A current (referred to as a first direction current) in the direction shown by FIG.
When the magnetic flux is generated in the direction shown by d, the magnetic fluxes 34a and 34
4d decreases and magnetic fluxes 34b and 34c increase,
A magnetic flux 27 passing through the mover 26 is generated. When the circumferential surface portion of the mover 26 facing the stator is in a magnetically saturated state, the magnetic flux of the stators 14c and 14b increases. 2
7) flows in the order of the side end 26a of the mover 26 → the inside of the mover 26 → the side end 26b of the mover 26 → the stator 14b. The magnetic flux flowing through the side end portions 26a and 26b causes the movable element 26 to have a counterclockwise driving torque 25.
a and 25b occur and rotate from the unstable equilibrium position shown in FIG. 8 to the stable position shown in FIG. That is, the mover 26
Starts rotating counterclockwise, the magnetic flux passing through the side ends 26a and 26b of the mover 26 (that is, the driving torque 25
a and 25b) increase and finally reach the stable state of FIG.

Conversely, in the unstable equilibrium state of the mover 26 shown in FIG. 8, a current in the opposite direction to the first direction current (referred to as the second direction current) flows through each of the coils 16a to 16d.
When a magnetic flux is generated in the directions indicated by arrows 38a to 38d in each of the stators 14a to 14d, the magnetic flux 3
4a and 34d increase, and the magnetic fluxes 34b and 34c by the permanent magnet decrease. Therefore, the side end 26 of the mover 26
c and 26 d (FIG. 9), the mover 2
A driving torque is generated in the clockwise direction in FIG. 6 and moves from the unstable equilibrium position shown in FIG. 7 to the stable position shown in FIG.

As described above, the conventional example shown in FIG. 6 has two stable states shown in FIGS.
Therefore, in order to move the mover 26 from the stable state shown in FIG. 10 or FIG. 11 to the position shown in FIG. 8 and continue the vibration, the mover position return means such as the leaf spring 28 must be used. .

(A) A current in the first direction is applied to the coils 14a to 14d,
When the mover 26 moves from the position shown in FIG. 8 to the stable position shown in FIG. 10, the current flowing through the coils 14a to 14d is reduced to zero,
The movable element 26 is forcibly returned to the position shown in FIG. 8 by using the restoring force of the leaf spring 28. (B) Next, a current in the second direction is supplied to the coils 16a to 16d, and when the mover 26 is moved from the position shown in FIG. 8 to the stable position shown in FIG. 11, the current supplied to the coils 14a to 14d is reduced to zero. The movable element 26 is returned from the stable position in FIG. 11 to the position shown in FIG. The above operations (a) and (b) are repeated to
Is vibrated about the axis 24.

The dimensions D, H, and T of the mover shown in FIG.
As described above, the mover 26 and the stators 14a to 14d
The minimum distance (clearance) to each is 0.1 mm,
A vibration test piece (moment of inertia = 0.4 × 10 ⁻⁶ kg · m ² ) is attached to the shaft 24 to which the mover 26 is fixed, and the coils 16a to 16d have a frequency of 400 Hz and an effective value of 100 AT (ampere turn) sine. When a wave current was applied, the amplitude of the vibrator was 5 ^° .

FIG. 12 is a diagram for explaining a case where the apparatus shown in FIG. 6 is used for a fatigue test of the flexible printed wiring board 40. The device shown in FIG. 8 is housed inside the cover (outer box) 42, and the vibrating reed 44 is fixed to one end of the shaft 24 (not shown in FIG. 11). Further, one end of the wiring board 40 is fixed to the vibrating reed 44 and the other end is fixed to the holder 46 to perform a fatigue test. Note that the device according to the present invention can also be applied to the application example shown in FIG.

As described above, the driving torque for vibrating the mover 26 is generated by the magnetic flux passing through the side ends 26a-26b and 26c-26d of the mover 26. However, as is apparent from FIGS.
Since the distance from the side end portions 26a to 26d of 6 to the stator is large, there is a problem that a sufficient driving torque cannot be obtained. Therefore, in the above-described conventional example, in order to increase the driving torque, it is necessary to increase the current flowing through the coil wound on the stator.

[0016]

SUMMARY OF THE INVENTION An object of the present invention is to devise the shape of the stator and to increase the driving torque of the mover for the same current value as compared with the conventional example.

[0017]

The vibration type actuator according to the present invention comprises (a) a pair of permanent magnets attached to a yoke, and (b) two pairs of stators provided between the pair of permanent magnets. (C) a movable member provided in a space surrounded by the two pairs of stators and capable of vibrating within a predetermined range in a circumferential direction;
An actuator having a coil wound around each of the pair of stators to change the magnetic flux of the stator, and (e) a return unit connected to the mover and returning the mover to a center position of vibration. In addition, each of the two pairs of stators has a protruding portion that protrudes into the space outside the movable range of the mover.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. FIG. 1 schematically shows a vibration type actuator according to the present invention. The device shown in FIG. 1 differs from the conventional example in the shape of the stator. Other configurations of the apparatus of FIG. 1 are the same as the corresponding configurations of FIG. 1 that are the same as those in FIG. 6 are denoted by the same reference numerals.

Next, the operation of the apparatus according to the present invention will be described with reference to FIGS. The permanent magnets 12a and 12a
The magnetic flux amount of the coils 16a to 16b is the same as in the conventional example.
It is set to be much larger than the respective magnetic flux amounts of 16d.

The difference between the present invention and the conventional example is that the stators 14a, 14b, 14c and 14d are different as shown in FIGS.
Has projections 50a, 50b, 50c and 50d, respectively. These projections 50a to 50d
The movable member 26 is out of the oscillatable range and the stator 14a
It protrudes into a cylindrical space surrounded by 〜14d.

FIG. 2 is a view showing a state in which the current flowing through the coils 16a to 16d is set to zero and the mover 26 is stopped at a horizontal position. Therefore, similarly to the conventional example, the magnetic force lines 34a to 34d indicated by broken lines are shown. Is based on the permanent magnets 12a and 12b. In FIG. 2, the shaft 24 of the mover 26 is not shown.

In the state shown in FIG. 2, the coils 16a to 16d
, A current (referred to as a first-direction current) in the direction shown in FIG.
When magnetic fluxes are generated in the directions indicated by arrows 36a to 36d in each of 4a to 14d, magnetic fluxes 34a and 34d decrease and magnetic fluxes 34b and 34c increase, and magnetic flux 27 passing through mover 26 is generated. When the circumferential surface of the mover 26 facing the stator is magnetically saturated, the stator 14
Since the magnetic fluxes c and 14b increase, as shown in FIG. 3, a part 27 of the magnetic flux in the mover 14c is converted into a side end 26a of the mover 26 → the inside of the mover 26 → a side end of the mover 26. The portion 26b flows like the stator 14. The magnetic flux flowing through the side ends 26a and 26b causes the mover 26 to apply a counterclockwise torque 25a,
5b occurs, and rotates from the unstable equilibrium position shown in FIG. 3 to the stable position shown in FIG. That is, when the mover 26 starts to rotate counterclockwise, the magnetic flux passing through the side ends 26a and 26b of the mover 26 (that is, the torques 25a and 25
b) accelerates and eventually reaches the stable state of FIG.

In the present invention, as the mover 26 rotates counterclockwise, the side end 26a of the mover 26 approaches the protrusion 50 and the side end 26b approaches the protrusion 50b. It can be understood that the driving torques 25a and 25b are larger than those in the conventional example.

Conversely, in the unstable equilibrium state of the mover 26 shown in FIG. 2, a current in the opposite direction to the first direction current (referred to as a second direction current) flows through each of the coils 16a to 16d.
When a magnetic flux is generated in the directions indicated by arrows 38a to 38d in each of the stators 14a to 14d, the magnetic flux 3
4a and 34d increase, and the magnetic fluxes 34b and 34c by the permanent magnet decrease. Therefore, the side end 26 of the mover 26
c and 26d (FIG. 3), the mover 2
6, a torque is generated in the clockwise direction and moves from the unstable equilibrium position shown in FIG. 2 to the stable position shown in FIG. Similar to the rotation of the mover 26 in the counterclockwise direction, as the mover 26 rotates in the clockwise direction, the side end 2 of the mover 26
6c approaches the projection 50d, and the side end 26d approaches the projection 50a.
It can be understood that 5b is larger than the conventional example.

The dimensions of the mover 26 (dimensions D, H, and T shown in FIG. 7) are the same as those in the conventional example, and the minimum distance (clearance) between the mover 26 and each of the stators 14a to 14d is 0.1 mm. 1 mm, and a vibration test piece (moment of inertia = 0.4 × 10 ⁻⁶ kg · m) is attached to the shaft 24 to which the mover 26 is fixed.
² ) is attached, and the frequency 40 is applied to the coils 16a to 16d.
When a sine wave current of 100 Hz (ampere turn) with an effective value of 0 Hz was passed, the amplitude of the vibrator was 8 ^° .

[0026]

As described above, according to the present invention, the stator 15a
The drive torque of the mover 26 can be made larger than that of the conventional example by changing the shape of 〜15d as described above. Along with this effect, there is also an effect that the same driving torque as in the conventional example can be obtained even if the current flowing through the coil is small.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a vibration-type actuator according to the present invention.

FIG. 2 is a view for explaining a vibration operation of a mover according to the present invention.

FIG. 3 is a diagram for explaining the vibration operation of the mover according to the present invention.

FIG. 4 is a diagram for explaining the vibration operation of the mover according to the present invention.

FIG. 5 is a diagram for explaining the vibration operation of the mover according to the present invention.

FIG. 6 is a diagram illustrating a conventional vibration-type actuator.

FIG. 7 is a perspective view of the mover shown in FIG. 6;

FIG. 8 is a view for explaining a vibration operation of a conventional mover.

FIG. 9 is a view for explaining a vibration operation of a conventional mover.

FIG. 10 is a view for explaining a vibration operation of a conventional mover.

FIG. 11 is a view for explaining a vibration operation of a conventional mover.

FIG. 12 is a perspective view showing an application example of a vibration type actuator.

Claims (1)

(57) [Claims] (A) a pair of permanent magnets attached to a yoke; (b) two pairs of stators provided between the pair of permanent magnets; and (c) two pairs of stators. A mover provided in an enclosed space and capable of vibrating within a predetermined range in a circumferential direction; (d) a coil wound around each of the two pairs of stators to change a magnetic flux of the stator; e) a return means connected to the mover and returning the mover to the center position of the vibration, wherein each of the two pairs of stators is out of the vibrable range of the mover. A vibration-type actuator having a protrusion protruding into the space.