JPH07337051A - Linear displacement driver - Google Patents

Abstract

PURPOSE:To drive an object linearly with high accuracy while preventing electric interference with the peripheral electronic circuit by arranging a plurality of bimetals passing the current in different directions alternately in the radial direction and disposing a push rod at the drive section. CONSTITUTION:Bimetals 11a, 11b, 12a, 12b, 13a, 13b, 14a, 14b, 15a, 15b, 16a, 16b, 17a, 17b, 18a, 18b passing the current in different directions are arranged alternately in the radial direction. When a current is fed to the bimetal, self- heating takes place in the bimetal because of the resistance component thereof. Consequently, the bimetal is bent to cause linear displacement of a push rod 30 fixed to the supporting part 10a at a drive section 10. Furthermore, the induced magnetic fields are offset to reduce the leakage flux. This structure provides a highly accurate linear displacement of an object while preventing electric interference with the peripheral electronic circuit.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a linear displacement driving device for linearly driving each part such as a beam reflecting mirror or a focus lens provided in electronic equipment, optical equipment and the like.

[0002]

2. Description of the Related Art As a conventional linear displacement driving device for electronic equipment, optical equipment, etc., there is, for example, Japanese Patent Laid-Open No. 62-171.
No. 453 proposes a linear displacement drive device that drives a guide shaft for linear displacement by exciting an electromagnet to drive a pen of a recording device or perform valve control. Further, Japanese Utility Model Application Laid-Open No. 2-39371 proposes a linear displacement driving device that enables linear displacement driving of a head by a piezoelectric element to enable fine adjustment tracking of the head.

Further, in Japanese Patent Laid-Open No. 3-44713, a movable electrode plate is provided on a movable portion swingably attached to a fixed portion by a spring, and the fixed electrode plate which opposes the movable electrode plate is provided on the fixed portion. There has been proposed a linear displacement driving device having a configuration in which a voltage is applied between the movable electrode plate and the fixed electrode plate to generate an electrostatic force to drive the movable portion in a linear displacement.

Further, in Japanese Utility Model Laid-Open No. 4-16622, a piezoelectric element, a rotary slider crank mechanism for converting the expansion of the piezoelectric element into a rotary motion, and a rotary motion converted by the rotary slider crank mechanism into a linear displacement motion. A linear displacement driving device for an optical disc pickup has been proposed, which is configured to adjust the position of an objective lens by a displacement magnifying mechanism portion including a four-bar parallel link mechanism for converting to.

[0005]

However, in the linear displacement driving device of the above-mentioned Japanese Patent Laid-Open No. 62-171453, the guide shaft is linearly driven by exciting the electromagnet. However, there is a problem in that the magnetic flux of the magnetic field is generated and interferes with an electronic circuit arranged around the linear displacement driving device to exert an adverse effect. In addition, the actual use of the piezoelectric element 2-39371
In the linear displacement driving device disclosed in Japanese Utility Model Publication No. 4-166622 and Japanese Patent Application Laid-Open No. 3-44713 applying electrostatic force, a leakage electric field is generated and interferes with an electronic circuit arranged around the linear displacement driving device. There was a problem that it adversely affected.

In order to prevent such electrical interference, Japanese Patent Laid-Open No. 59-5901 and Japanese Utility Model Laid-Open No. 62-15161.
It is also conceivable to mechanically drive the linear displacement of the object by a combination of a cam or a rack and pinion like the linear displacement drive device of No. However, in the case of such a mechanical drive, there is a problem that backlash occurs in a contact portion between parts such as gears, and drive accuracy is deteriorated. Further, if the object is mechanically driven for linear displacement by a combination of a cam or a rack and pinion, the number of parts will increase and the structure will become complicated, making it possible to reduce the size and weight of electronic devices and improve reliability. However, it is not preferable to apply such a technique particularly in the field of artificial satellites, which requires small and lightweight mounting equipment and reliability.

The present invention has been made in view of the above problems, and has a simple structure, can prevent electrical interference with peripheral electronic circuits, and can accurately linearly displace an object. It is an object of the present invention to provide a linear displacement drive device that can be driven and can be reduced in size and weight and improved in reliability.

[0008]

In order to achieve the above object, a linear displacement driving device according to a first aspect of the present invention arranges a plurality of bimetals in which currents flow in different directions in an alternating and radial manner, and inside each of these bimetals. The drive unit has a support portion for supporting the push rod by the end portion, a fixing member for fixing the outer end portions of these bimetals, and the push rod supported by the support portion of the drive portion. Is provided.

A linear displacement driving device according to a second aspect of the present invention is configured such that the driving portion has the plurality of bimetals continuously and radially arranged, and the linear displacement driving device according to the third aspect is the driving device. The section has a configuration in which a plurality of a pair of bimetals, each of which is formed by connecting one ends of two bimetals in which currents flow in different directions, are radially arranged.

According to a fourth aspect of the present invention, there is provided a linear displacement drive device in which the drive section is configured so that the positions of two bimetals which make a pair are crossed with each other in the middle of these bimetals and exchanged. In the linear displacement driving device, the fixing member is a fixing frame that fixes the outer end of the bimetal.

[0011]

According to the linear displacement driving device of the present invention having the above structure, when a current is applied to the bimetal, the resistance of the bimetal causes the bimetal to generate heat. Due to this self-heating, the bimetal is curved, and the push rod attached to the support portion is linearly displaced and driven. Here, by arranging the bimetals in which currents flow in different directions alternately and radially, the magnetic fields generated by the applied currents are offset, leakage magnetic flux does not occur, and electrical interference with surrounding electronic circuits is prevented. Can be prevented.

[0012]

Embodiments of the linear displacement driving apparatus of the present invention will be described below with reference to the drawings. First, a linear displacement driving device according to the first embodiment of the present invention will be described. 1A and 1B show a linear displacement driving device according to the first embodiment, where FIG. 1A is a plan view and FIG. 1B is an A in FIG.
FIG. In the linear displacement driving device of this embodiment,
The drive unit has a configuration in which a plurality of bimetals in which currents flow in different directions are arranged alternately and radially, and these bimetals are continuously formed.

In FIGS. 1 (a) and 1 (b), reference numeral 10 is a drive section, which is a bimetal 11a, 1 through which current flows in different directions.
1b to 18a and 18b are arranged continuously and radially. Here, the bimetals 11a and 11b (~
18a and 18b) form a pair. The outer ends of these bimetals 11a, 11b to 18a, 18b are fixed by a circular fixing frame (fixing member) 20, and the inner ends form a supporting portion 10a of the push rod 30. Further, the outer end portions of the bimetals 11a and 11b are projected from the fixed frame 20, and the terminal portion 1 for current application is formed.
0b is formed.

The fixed frame 20 has a bimetal 11a,
11b to 18a, each outer end of 18b and the terminal portion 10b
Engagement recesses 20a to 20h are formed to engage with. The push rod 30 has a cylindrical shape, and an engaging groove 30a that engages with a support portion 10a formed by the inner ends of the bimetals 11a, 11b to 18a, 18b is formed at the lower end. .

In the present embodiment, in order to simplify and miniaturize the equipment, each bimetal 1 forming the drive unit 10 will be described.
The outer end portions of 1a, 11b to 18a, 18b are fixed by a circular fixing frame 20, but each bimetal 1
The outer end portions of 1a, 11b to 18a, 18b may be individually fixed by separate fixing members.

Next, the operation of the linear displacement driving device of this embodiment having the above structure will be described with reference to FIGS. 1 and 2. FIG. 2A is a side cross-sectional view showing a state in which the linear displacement driving device is driven for linear displacement, and FIG. 2B is a plan view showing a direction of a current flowing through a bimetal forming a driving portion of the linear displacement driving device. It is a figure.

Each bimetal 11a, 11b of the drive unit 10
-18a and 18b are usually, as shown in FIG.
It is in a straight state. Here, when a power supply is connected to the terminal portion 10b of the drive unit 10 and an alternating current or a direct current is applied, the bimetals 11a, 11b to 18a, 18b are affected by the resistance components of the bimetals 11a, 11b.
8a and 18b generate self-heating. Then, as a result of this self-heating, as shown in FIG.
1a, 11b to 18a, 18b are curved, and the support portion 10a
The push rod 30 attached to is driven for linear displacement.

Since the driving amount of the push rod 30 is proportional to the amount of self-heating of each bimetal 11a, 11b to 18a, 18b, the driving amount of the push rod 30 can be changed by changing the value of the applied current. Can be adjusted. Further, as shown in FIG. 2B, the applied currents flowing through the bimetals 11a, 11b to 18a, 18b are the same as those of the paired bimetals 11a as indicated by arrows in the figure.
Since the currents 1b (to 18a and 18b) flow in opposite directions, the magnetic fields generated by these applied currents cancel each other out.

According to the linear displacement driving device of the present embodiment having such a structure, the magnetic field generated by the applied current is canceled out, so that the leakage magnetic flux is not generated and the electric interference with the peripheral electronic circuits is prevented. be able to. Further, since the driving portion 10 formed by the bimetals 11a, 11b to 18a, 18b, and the drive displacement is generated by the fixed frame 20 and the push rod 30, the number of parts is small, the device is simplified, and the size and weight are reduced. And reliability can be improved. Further, since the linear displacement driving device does not use any mechanical elements such as gears, backlash does not occur, and the object can be accurately driven for linear displacement.

Next, a linear displacement driving device according to a second embodiment of the present invention will be described with reference to FIG. FIG. 3 is a plan view showing a linear displacement driving device according to the second embodiment.

In the figure, in the linear displacement drive device of this embodiment, the drive section 40 is connected to one end of two bimetals 41a, 41b (to 48a, 48b) through which currents flow in different directions, and these pairs are connected. Eggplant Bimetal 41a, 41
b to 48a and 48b are arranged radially.

According to such a configuration, these bimetals 41 are connected through the respective terminal portions 40a to 40h of the driving portion 40.
When a current is applied to a, 41b to 48a, 48b, the applied current flowing through each of the bimetals 41a, 41b to 48a, 48b at this time is as shown by the arrow in the figure. The magnetic fields generated by the applied currents cancel each other because they flow in opposite directions. Therefore, even with such a configuration, the same effect as that of the first embodiment can be obtained.

Next, a linear displacement driving device according to a third embodiment of the present invention will be described with reference to FIG. FIG. 4 is a plan view showing a linear displacement driving device according to the third embodiment. Further, FIG. 5 shows a bimetal forming a drive portion of the linear displacement drive device, FIG. 5A is a partially enlarged view, and FIG. 5B is a perspective view showing an intersecting state of the bimetal. is there.

In these drawings, in the linear displacement driving device of the present embodiment, the positions of two bimetals 51a, 51b (~ 58a, 58b) forming a pair, which form the drive unit 50, are shown by the positions of these bimetals 51a, 51b (~ 58a). , 58
The structure is such that they are crossed and replaced in the middle of b). Further, the bimetals 51a and 5b are provided at the intersection 51c (to 58c) of the bimetals 51a and 51b (to 58a and 58b).
An insulator 51d (to 58d) for preventing contact between 1b (to 58a and 58b) is interposed.

According to this structure, the bimetals 51a and 51b are connected via the terminal portion 50a of the driving portion 50.
When a current is applied to ~ 58a, 58b, each bimetal 5
The applied currents flowing in 1a, 51b to 58a, 58b are as shown by arrows C to H in FIG. 5 (a), and by the applied currents of arrow C and arrow G, arrow D and arrow F, and arrow E and arrow H, respectively. The generated magnetic fields cancel each other out.

According to the linear displacement driving device of this embodiment, the magnetic field generated by the applied current in the vertical direction (the applied current in the arrow C and the arrow G, the applied current in the arrow D and the arrow F) and the applied current in the horizontal direction. The magnetic fields generated by (the currents applied by the arrow E and the arrow H) are canceled by each other, so that no leakage magnetic flux is generated in the drive unit 50, and electrical interference with peripheral electronic circuits is surely prevented. You can

The linear displacement driving device of the present invention is not limited to the above embodiments. In the first and third embodiments, in order to simplify the configuration, a plurality of bimetals 11a, 11b to 18a, 18 in which currents flow in different directions.
b (51a, 51b to 58a, 58b) are arranged continuously and radially, and in the second embodiment,
Two bimetals 41a and 41b in which currents flow in different directions
(-48a, 48b) is configured by connecting one ends to each other, but the present invention is not limited to this, and a plurality of independent bimetals in which currents flow in different directions are arranged alternately and radially to form a drive unit. May be.

[0028]

As described above, according to the linear displacement driving device of the present invention, it is possible to prevent electrical interference with the surrounding electronic circuits while having a simple structure, and It is possible to drive linear displacement with high accuracy,
It is possible to reduce the size and weight of the device and improve the reliability.

[Brief description of drawings]

1A and 1B show a linear displacement driving device according to a first embodiment of the present invention, in which FIG. 1A is a plan view and FIG. 1B is a sectional view taken along line AA of FIG. 1A. is there.

FIG. 2 (a) is a side sectional view showing a state in which the linear displacement driving device is driven for linear displacement, and FIG. 2 (b) is a current flowing in a bimetal forming a drive portion of the linear displacement driving device. It is a top view which shows the direction of.

FIG. 3 is a plan view showing a linear displacement driving device according to a second embodiment of the present invention.

FIG. 4 is a plan view showing a linear displacement driving device according to a third embodiment of the present invention.

5A and 5B are views showing a bimetal forming a drive portion of the linear displacement driving device, FIG. 5A is a partially enlarged view, and FIG. 5B is a perspective view showing an intersecting state of the bimetal.

[Explanation of symbols]

10, 40, 50 Drive part 10a Support part 10b, 40a-40h, 50a Terminal part 11a, 11b-18a, 18b (41a, 41b-4)
8a, 48b, 51a, 51b to 58a, 58b) Bimetal 20 Fixed frame (fixing member) 20a to 20h Engagement recess 30 Push rod 30a Engagement groove 51c to 58c Intersection 51d to 58d Insulation part

Claims (5)

[Claims] 1. A drive unit in which a plurality of bimetals in which electric currents flow in different directions are alternately and radially arranged, and a support unit for supporting a push rod is formed by inner ends of these bimetals, and these bimetals. A linear displacement driving device, comprising: a fixing member that fixes an outer end of the driving unit; and the push rod supported by a supporting unit of the driving unit. 2. The linear displacement drive device according to claim 1, wherein the drive section has a configuration in which the plurality of bimetals are continuously and radially arranged. 3. The linear displacement drive device according to claim 1, wherein the drive section radially arranges a plurality of pairs of bimetals, each of which is formed by connecting one ends of two bimetals in which current flows in different directions. 4. The linear displacement drive device according to claim 1, wherein the drive unit is configured so that the positions of two bimetals forming a pair are crossed and changed in the middle of the bimetals. 5. The linear displacement driving device according to claim 1, wherein the fixing member is a fixing frame for fixing an outer end portion of the bimetal.