JPS61177155A - Drive device - Google Patents

Abstract

PURPOSE:To compose a drive device which can drive efficiently even by high frequency by varying the size of air gaps of a magnetic circuit which has one or more air gaps and a magnetomotive force source by a laminated piezoelectric effect element. CONSTITUTION:A movable unit 38 having toothed poles 32a-32d is opposed through air gaps (g) to a stator 31 having a plurality of toothed poles 31a-31b at an equal interval. The toothed poles 32a-32d of the unit 38 are disposed at the phase differences of 0 deg., 90 deg., 180 deg., 270 deg. to the toothed poles 31a-31f of the stator 31, and supported through electrostrictive elements 35a-35d to a support member 36. Further, yokes 33a, 33b and a permanent magnet 34 are provided. Power sources Ea-Ed apply drive voltages to the elements 35a-35d. When the Ec is, for example, increased and the Ed is reduced by a controller, not shown, the element 35c is elongated and the element 35d is contracted. Thus, one of the corresponding air gaps are narrowed, and the other is widened to increase or decrease a magnetic flux density, thereby moving a movable unit 37 rightward. Thus, it can be operated efficiently even by high frequency.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a drive device suitable for use in stepping motors, plungers, etc.

[Summary of the invention]

The present invention changes the size of the air gaps in the magnetic circuit using a laminated piezoelectric effect element, thereby making the magnetic flux density of each air gap unbalanced or balanced, thereby eliminating the drawbacks of conventional electromagnetic drive devices. It is possible to solve problems such as low efficiency, heat generation, and characteristic deterioration during high frequency driving.

[Conventional technology]

Drive devices using electromagnets, which have been widely used in the past, generally configure a magnetic circuit by arranging a fixed yoke and a movable yoke with one or more gaps in between. It is configured to conduct magnetic flux from a source of magnetomotive force. Then, the magnetic flux density of each gap is changed unbalancedly by a current magnetic field to create a difference in the attraction force acting on each gap, and based on this difference in attraction force, the movable yoke is given thrust, rotational force, holding force, etc. The driving force is generated.

Examples in which a conventional drive device is applied to a stepping motor, a plunger, etc. are shown in FIGS. 9 to 13.

FIG. 9 shows a composite permanent magnet type linear stepping motor, in which 1 is a fixed yoke with magnetic pole teeth 1a to 1f at a predetermined pitch.
is formed. 2 and 3 are movable yokes with magnetic pole teeth 2a
, 2b, 3a, and 3b are formed. This magnetic pole tooth 2a
-3b are arranged with phase differences of 0°, 90°, 180°, and 270°, respectively, with respect to the pitch of the magnetic pole teeth Ia-1f. 4 and 5 are drive coils, 6 is a permanent magnet, 7 is a support member, and 8 is a flow of magnetic flux.

In this state shown in Fig. 9, the coil 4.5 is not energized,
The magnetic flux between each of the magnetic pole teeth 1a to 1f and 2a to 3b is balanced, and the moving yoke 2.3 is stopped. In this state, the coil 4 is rotated so that the moving yoke 2.3 is magnetized in the direction shown in the figure.
．． When 5 is energized, the magnetic flux between the magnetic pole teeth lc and 2b decreases, and the magnetic flux density between the magnetic pole teeth 1d and 3a increases, creating an attractive force, which causes the movable yoke 2.3 to move as shown in the figure. Move to the left.

10 and 11 show a variable reluctance type stamping motor. In FIG. 10, 9 is a fixed yoke on which magnetic pole teeth are formed, 10 is a rotating yoke on which magnetic pole teeth are formed, and 11 is a drive coil. and is provided on the magnetic pole teeth of the fixed yoke 9.

FIG. 11 shows the wiring of the coil 11, and each coil 3
The two coils 11 facing each other are connected as a set, and each set is connected to a power source via switches S+, St, and Ss.

In the above configuration, the switches St, St, Si
By sequentially turning on the coils 11, each set of coils 11 sequentially generates a current magnetic field, and the rotating yoke 10 rotates.

Figure 12 shows a galvano scanner for driving a laser mirror, etc., where 12 and 13 are fixed yokes each having magnetic pole teeth, 14 and 15 are permanent magnets, 16° and 17 are drive coils, and 18 is a rotating yoke. .

According to the above configuration, by energizing the coils 12, 13, the magnetic flux density between the rotating cork 18 and each magnetic pole tooth changes, and the rotating yoke 18 rotates by a predetermined angle.

FIG. 13 shows a plunger type solenoid. By energizing the drive coil 19, a current magnetic field generated in the fixed yoke 20 passes through the movable yoke 21, so that the movable yoke 21 resists the spring 22. Fixed yoke 20
sucked inside.

[Problem that the invention attempts to solve]

The conventional electromagnetic drive device described above has the following drawbacks.

(1) During operation, the current value is determined by the applied voltage and the impedance of the drive coil, so the efficiency is lower than that of a DC motor in which the current is approximately proportional to the load.

(2) When holding a fixed position or performing so-called microstep operation, which is performed in recent fine positioning control by energizing multiple phases and interpolating step 7,
It is necessary to keep the excitation current flowing. This results in extremely low efficiency and causes heat generation.

(3) Since the impedance of the coil that generates the current magnetic field increases at high frequencies, the generated torque decreases and the rise characteristics deteriorate.

(4) Electromagnetic noise is generated due to the current flowing through the coil.

[Means for solving problems]

The present invention provides a laminated piezoelectric effect element to change the size of the air gap in the magnetic circuit.

〔Example〕

FIG. 1 shows a first embodiment, which corresponds to the linear stepping motor shown in FIG. 9 described above.

In FIG. 1, 31 is a fixed yoke with magnetic pole teeth 31a to 3.
1f are provided at a predetermined pitch. 32a-32d
is a movable yoke that connects the magnetic pole teeth 31a to 31f with a predetermined gap g and with respect to the predetermined pitch.
They are arranged with phase differences of 90', 180', and 270°. 33a.

33b is a yoke, and 34 is a permanent magnet.

The movable yokes 32a to 32. d is the electrostrictive element 35a-3
It is supported by the support member 36 via 5d. Each of the electrostrictive elements 35a to 35d is configured to receive a driving voltage from a power source E, -E, respectively. The movable yoke 32a
~32d1 The arrow 3 is
A movable part 38 that moves in seven directions is configured. In addition, 3
9 indicates the flow of magnetic flux.

As the electrostrictive elements 35a to 35(l), an electrostrictive element 35 consisting of a known laminated piezoelectric effect element as shown in FIG. 2 is used.

In FIG. 2, a plurality of longitudinal effect piezoelectric elements 40 are stacked with glabellar electrodes 41, 42 and insulating layers 43, 44 interposed therebetween,
Each interlayer electrode 41 is connected to an electrode 45, and each interlayer electrode 42
is connected to the electrode 46.

The electrostrictive element 35 configured as described above has electrodes 45.4
By applying a driving voltage between 6 and 6, it expands in the direction shown by arrow 47, and when the voltage is removed, it returns to its original length.

Next, Figure 3A shows the operation of the motor configured as shown in Figure 1.
This will be explained together with -D.

In Figure 1, with each power supply turned off, E, =E b
= E C= E a = O, the magnetic flux 39 from the magnet 34 flows along the illustrated path. At this time, the magnetic pole tooth 31
The movable portion 38 is moved, for example, to the left by the suction force at the portion of the movable yokes a to 31f and the movable yokes 32a to 32d where the opposing area is the largest, and is stabilized as shown in FIG. 3A.

Here, when bias voltages of equal magnitude (E-=Eb=EC=Ea) are applied to the electrostrictive elements 35a to 35d, each of the electrostrictive elements 35a to 35d uniformly expands and the gap g
becomes smaller, but the stable state remains unchanged.

When EC is increased and E is decreased in this state, the electrostrictive element 35c expands and the corresponding gap g narrows.
As the magnetic flux increases, the electrostrictive element 35C shrinks, the corresponding gap g widens, and the magnetic flux decreases. As a result, as shown in FIG. 3B, the movable portion 38 is attracted, moves to the left from A in the same figure, and becomes stable. Next, as shown in Figure C, EC
,E.

is returned to the above bias voltage, and E3 is increased to make Eb
When , the corresponding gap g changes and the movable part 3
8 moves further and stabilizes. Furthermore, as in the same diagram, E
,,F,b are returned to the bias voltages, Ed is increased, and EC is decreased, the movable part 38 moves and stabilizes.

By sequentially switching the voltages E8 to Ed as described above, the movable portion 38 can be moved in steps. Note that it is also possible to fix the movable part 38 and move the fixed yoke 31. Furthermore, by controlling how voltage is applied, it is also possible to move in an analog manner. Further, the movable portion 38 and the fixed yoke 31 may be formed into an annular or curved shape.

FIG. 4 shows a second embodiment, which is applied to the plunger of FIG. 13.

In FIG. 4A, a cylindrical main yoke 52 and a back yoke 53 are supported by a support member 51. A movable yoke 54 is biased inside the main yoke 52 by a spring 55.
Further, it is provided with a gap g1 interposed between the main yoke 52 and a portion thereof protruding from the main yoke 52. One end of the spring 55 is fixed to a fixing member 56. back yoke 53
The electrostrictive element 35 is provided inside and is configured to be supplied with voltage E. A communication yoke 58 and a magnet 59 are integrally and movably provided between the back yoke 53 and the main yoke 52, and are biased by a spring 60 whose one end is fixed to the fixing member 56.

In the state shown in FIG. 4A, when E=0, the magnet 59 is in contact with the electrostrictive element 35 by the spring 60, and the shorting yoke 58 is in contact with the back yoke 53.

At this time, there is a gap gz between the main yoke 52 and the back yoke 53.
(However, gz > g+). As a result, magnetic flux 61 flows through back yoke 53. Next, when a predetermined voltage E is applied to the electrostrictive element 35 in this state, the electrostrictive element 35 expands and pushes the magnet 59 against the spring 60, as shown in FIG. leaves the back yoke 53 and contacts the main yoke 52. Therefore, the magnetic flux 61 flows through the main yoke 52 and the movable yoke 54, which causes the movable yoke 54 to move toward the spring 55.
The main yoke 52 is drawn into the main yoke 52.

If the voltage E is set to O from this state, each member will be moved to the bar 255.
60, and returns to the state shown in FIG. 4A again. still,
If the electrostrictive element 35 and the magnet 59 are bonded together, the spring 60 can be omitted.

FIG. 5 shows a third embodiment, in which the present invention is applied to an excitation device. This embodiment has substantially the same configuration as the plunger shown in FIG. 4 described above, with the movable yoke 54 removed. Note that the same reference numerals are given to the members corresponding to those in FIG. 4.

In FIG. 5A, there are magnetic pole teeth 52 at the tip of the main yoke 52.
a and 52b are provided facing each other with a gap g3 in between. When a voltage E is applied to the electrostrictive element 35 from this state, a magnetic flux 64 flows as shown in FIG. 3B, and the gap g3 is excited.

Therefore, as shown by the imaginary line in this exciting part, the magnetic body 65
This magnetic body 65 can be attracted by bringing it close. In the case shown in the figure, since gz>gz, a part of the magnetic flux is transferred to the back yoke 5 as shown by the dotted line 66.
However, if the magnetic body 65 is brought closer, most of the magnetic flux will flow to the gap g3 side. Further, a gap can also be provided in the back yoke 53.

FIG. 6 shows a fourth embodiment, in which a stamping motor is constructed using six of the excitation devices shown in FIG. 5 above, and corresponds to the motors shown in FIGS. 10 and 11. .

In FIG. 6, six excitation devices A to F are arranged at equal intervals by a ring-shaped support member 62, and a rotating yoke 63 in which magnetic pole teeth are formed is arranged at the center. The plungers have A facing each other, and a pair is made of B, ElC, and F.
By sequentially energizing each set, the rotating yoke 63 rotates. In addition, in Figure 6, A,! The case where the set =D is energized is shown.

7 and 8 show the fifth embodiment, and the twelfth embodiment
This corresponds to the galvano scanner shown in the figure.

In FIGS. 7 and 8, four fixed yokes 713-
71d, a gap g4 is provided between the fixed yokes 71a and 71b, and a permanent magnet 72a is interposed between the fixed yokes 71a and 71b. A gap g4 is provided between the IC and 71d, and a permanent magnet 72b is interposed. Further, the rotating yoke 73 has a predetermined gap g with respect to the fixed yokes 71a to 71d.

It is arranged through. A fixed portion 74a formed at one end of the shorting yoke plate 74a is provided on one side of the fixed yoke 71d.
, are adhered to each other, and a short circuit portion 74a2 formed at the other end of the fixed yoke 74a is in contact with one side surface of the fixed yoke 71b. A support plate 75a is provided on the other side of the fixed yoke 71d.
The supporting plate 75aC supports the electrostrictive element 35a, and its tip is in contact with the shorting yoke plate 74a.

Fixed yoke? A fixed part 74b formed at one end of the shorting yoke plate 74b is adhered to one side of the IC, and a shorting part 74b2 formed at the other end of the fixed yoke 71b contacts one side of the fixed yoke 71a. ing. Fixed yoke 7
A support plate 75b is adhered to the other side surface of 1c, and the electrostrictive element 35b is supported on this support plate 75b, the tip of which is in contact with the shorting yoke plate 74b.

Next, the operation of the above configuration will be explained.

When no voltage is applied to the electrostrictive elements 35a and 35b, the fixed yokes 71d and 71b are connected to the short-circuited yoke plate 74.
a and is magnetically short-circuited by the fixed yoke 71c.
and 71a are magnetically short-circuited by a short-circuit yoke 74b. Therefore, it becomes difficult for magnetic flux to flow through the rotating yoke 73, and each gap g.

The magnetic flux is the minimum, and since their magnitudes are equal, no rotational force is generated.

For example, when a voltage is applied to the electrostrictive element 35a in this state, the electrostrictive element 35a expands and pushes up the shorting yoke plate 74a. As a result, the short circuit portion 74 of the short circuit yoke plate 74a
a2 leaves the fixed yoke 71b, and the magnetic short circuit is released. As a result, as shown in Figure 8, is it a magnet? The magnetic flux 76 of 2a is fixed yoke 71b = air gap 'gs - rotating yoke 7
3 - air gap g, - fixed yoke 71a - flows to magnet 72a.

Therefore, the gap g on the side of the fixed yokes 71a and 71b.

The magnetic flux density of the fixed yokes 71c and 71d becomes larger than the magnetic flux density of the air gap g on the side of the fixed yokes 71c and 71d.
A counterclockwise rotational force is generated.

Furthermore, if the electrostrictive element 35a is de-energized and a voltage is applied to the electrostrictive element 35b, the rotating yoke 73 rotates clockwise.

Further, by balancing the voltages applied to the electrostrictive elements 35a and 35b, the rotating yoke 73 can be held at an arbitrary position.

〔Effect of the invention〕

(1) Conventionally, the increase and decrease of the magnetic flux density in the air gap was controlled by electric current, but according to the present invention, it is possible to control by voltage, and efficiency can be greatly improved.

(2) Since no drive coil is used, there is no decrease in torque due to an increase in impedance even when driven at a high frequency.
Able to maintain responsiveness.

(3) When performing operations such as holding control and microstep control, conventionally a continuous excitation current was required, but with the present invention, it is only necessary to apply a voltage continuously, which improves efficiency by reducing current consumption. It is possible to improve the temperature and reduce heat generation.

[Brief explanation of drawings]

FIG. 1 is a side view showing the first embodiment of the present invention, FIG. 2 is a perspective view of a multilayer piezoelectric effect element, FIG. 3 is a side view showing the operation of FIG. 1, and FIGS. 6 and 6 are side views showing the second, third and fourth embodiments of the present invention, respectively, FIG. 7 is a perspective view showing the fifth embodiment of the present invention, and FIG. 8 is the seventh embodiment. Fig. 9 is a side view of a conventional linear stepping motor, Fig. 10 is a side view of a conventional stepping motor, Fig. 11 is a coil connection diagram of Fig. 10, and Fig. 12 is a conventional galvano scanner. FIG. 13 is a side view of a conventional plunger solenoid. In addition, in the symbols used in the drawings, 35, 35a, 35b-----One-layer type one-pressure N effect element 31-----------
------- One fixed yoke 32a to 32d ---
----1 movable yoke 34・--1---・--・-
−・− It is a permanent magnet.

Claims (1)

[Claims] A drive device comprising a magnetic circuit including one or more air gaps and a magnetomotive force source, the size of the air gaps being changed by a laminated piezoelectric effect element.