JPS5999977A - Linear motor - Google Patents

Abstract

PURPOSE:To accurately obtain a stable linear motion at a constant speed by disposing a cylindrical piezoelectric element in a ring-shaped element produced by bonding two piezoelectric elements. CONSTITUTION:A ring-shaped element 5 in which a bimorph type piezoelectric element produced by bonding two piezoelectric elements 51, 52 in reverse direction is formed in a ring shape, is secured to a stationary block 7. A cylindrical clamp 8 which is formed of piezoelectric elements radially stretching and shrinking is mounted on the inner peripheral side of the element 5. A shaft 10 which is penetrated through the cylindrical piezoelectric element is linearly moved by controlling a voltage applied to these piezoelectric elements.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a linear motor that is used in ultra-precision positioning mechanisms and the like and performs linear motion.

Conventional Structures and Problems Conventionally, in order to obtain linear motion, a method of converting the rotational motion of a stepping motor or DC motor into linear motion using a screw or cam has often been used.

Since these methods mechanically convert rotary motion into linear motion, they cannot completely eliminate play in the joints and vibrations of the motor, but they do have the problem of resulting in a structurally large device. be.

On the other hand, there are hydraulic cylinders and pneumatic cylinders that obtain direct linear motion, but these are very large devices.
It is difficult to control, so it is very difficult to perform ultra-precise positioning.

On the other hand, as a fine movement mechanism for highly precise positioning, an insect-type fine movement mechanism using an electrostrictive element or a magnetostrictive element is known.

FIG. 1 is an explanatory diagram of an insect-type fine movement mechanism using an electrostrictive element. The fine movement mechanism will be explained below according to the figures.

The fine movement mechanism has a structure in which clamp elements 2 and 3 are attached to both ends of an electrostrictive cable 1. In A, the clamp elements 2 and 3 are clamped onto the fixed stage 4 for identification. Free the clamp element 2 with your mouth. When you apply a voltage to the electrostrictive cable 1 with 0 and stretch it, the clamp element 2 moves 1" to the left in the figure. Fix the clamp element 2 with a trowel, and use E to release the clamp element 2. 3 is made free. When the voltage applied to the electrostrictive element 1 is cut off at , the 71L strain element 1 is constricted and the clamp element 3 moves to the left. When the clamp element 3 is fixed at 1, the state shown in A is obtained. The loop at 1 inch from A is the fine movement mechanism of the fine movement mechanism J Nizuno. As a method of clamping the clamp element, it is possible to use electromagnetic force or electrostatic force. good.

As mentioned above, since the strain caused by electrostriction of the electrostrictive element is extremely small, highly accurate positioning with minute movements is possible. However, there are the following problems. First, the intermittent movement of the insects Ij is effective for positioning, but cannot be used for stages that move at a constant speed. Second, since the strain caused by electrostriction of the electrostrictive rope is extremely small, the moving speed is low. During the third movement, the clamp element is free and in the shape f13, resulting in greater mechanical stability.

OBJECTS OF THE INVENTION It is an object of the present invention to obtain a near motor that is smaller than the above (also takes advantage of the advantages of the electrostrictive element R, and realizes frozen 1-2 diagonal motion with high precision.

Structure of the Invention The present invention is characterized in that two electrostrictive elements are connected in opposite directions. ,i
The combined ring-shaped element P, and the cylindrical electrostrictive elements arranged on the inner circumference of the ring-shaped element P, are connected to the cylindrical electrostrictive elements by controlling the voltage applied to them. This is a two-stroke linear motor that moves either the shaft or the shaft fixed to the periphery of the ring-shaped element row in a line 1b.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIGS. 2 and 3 show a first embodiment of the present invention. A bimorph electrostrictive element f-, which is formed by bonding two electrostrictive elements 51 and 52 in opposite directions, is formed into a ring shape.The outer periphery of the 2' ring-shaped elements 5 and 6 is attached to the fixed block 7! 4. Reasonable interval.・Install and secure. Cylindrical clamp elements 8 and 9 are attached to the inner peripheral sides of the ring-shaped elements 6 and 6, respectively, and are formed of electrostrictive elements that expand and contract in the radial force direction. 9, slide shaft 10 and &:t knee 4" key (d).

The ring-shaped element 5 is provided with electrodes 11 on both surfaces and the surface to be pasted, and as shown in the figure, a voltage A is applied between the surface to be pasted and the surface to be pasted. The clamp element 8゜9 is the inner and outer circumference.
An electrode 12 is formed at - and a voltage C is applied between them.

The ring elements 5, 6 and the clamp elements 8, 9 are insulated,
There is no wobbling during exercise.'': The sea urchins are able to move smoothly.

Next, the operation will be explained with reference to FIGS. 3 and 4. Third
2 in the figure shows the state of each element at time 2 in FIG. 4. It's ox, Figure 4a.

b is a voltage waveform applied to each of the ring-shaped elements 5 and 6, which is a triangular wave having an amplitude of {circle around (1)} and a rise-to-F rise time of To. Figures c and d are the voltage waveforms applied to the clamp elements 8 and 9, respectively. is also 0 and its displacement position is O. On the other hand, the clamp element 9 is impressed with the voltage 7711 shown in Fig. 4d, and the slide shaft 10 is clamped 1-22, and the voltage shown in Fig. 4 is applied to the ring-shaped element 6, causing the slide shaft 10 to be displaced at a speed V/To. are doing. In rl, two clamping elements -8,9
Both are electric r [h c .

d is applied, so the slide shut 10 is clamped, and the voltages a and b are also applied to the ring-shaped elements 6 and 6. , a pressure d of 7ti is applied to the clamp element 9, the clamp is removed, and the ring-shaped element-6 changes 1'j; l O
Return to position. On the other hand, the ring-like element i''-5'' changes f with the velocity V/To. In step 2, a circular voltage d is applied to the clamp element 9, and a voltage d is also applied to the ring-shaped element 9, which starts to displace at a speed V/To. , 9 is clamped to I/This slide shut 1o is at speed V/
Move to the left of the diagram with T o.

Figures 4e and 4f are timing charts 1 for the speed of the slide shaft 10 and the force applied thereto, respectively. As shown in e, the velocity is always constant at V/T o C) The force of the force fluctuates periodically but never becomes zero.

The present M, 5 examples are ring-shaped element 1: and clamp element 7.
...4 Although this is an example in which two soars are used, by increasing the number, the fluctuation in the force applied to the slide shaft 10 becomes smaller, and at the same time, the moving power of the slide shaft 1o becomes larger.

Further, although this embodiment is an embodiment in which the slide shaft 1.0 moves, it is also possible to fix the slide shaft 10 and move the block 7. In addition, since a bimorph type electrostrictive element is used, which allows a long movement distance, a large displacement can be obtained even with a low voltage, so it is possible to increase the speed.

Note that by controlling the phase, voltage value, and frequency of the voltage □ applied to the ring fall element and the clamp element, the manner of movement can be freely adjusted.

FIG. 5 shows an example in which the linear motor of the present invention is used in an ultra-precision lathe, in which a two-axis linear motor is used to form a curved surface by cutting. Since the surface is formed by controlling two axes, the moving mechanism requires continuous movement rather than an intermittent feeding mechanism. Furthermore, submicron positional accuracy is required. The linear motor of the present invention makes it possible to realize this requirement.

The configuration of FIG. 6 will be explained below. In order to obtain high rotational accuracy, a workpiece 14 is vacuum-adsorbed and attached to a spindle 13 using an air bearing. This is a 15-piece diamond blade tool. The feeding direction (X-axis) of the cutting tool 15 and the cutting direction (Z-axis) of the cutting tool are controlled by self-propelled linear motors 16, 17 using two slide guide shafts 161, 162 and 17j, iγ2, respectively.

FIG. 6 is a block diagram of the linear motor 16-17 shown in FIG. A plurality of bimorph electrostrictive elements 18 and clamp elements 19 are used. Slide guide shaft 20
is fixed and uses an air bearing 22 for smooth movement of the carriage 21 therealong. This configuration is in the X-axis direction.

2Mi are provided in each direction of the z-axis, and each slide guide shaft 20 is replaced by a two-axis slide guide shaft 161.
．． 162, 171.172. The feeding direction of the cutting tool 15 is the slide guide shaft 161,1.
The cutting depth of the cutting tool 15 is adjusted by moving the carriage 9 along the slide guide gear 7.62. The carriage 173 moves along the lines 171., 172 and the door is opened.

As described above, by using the linear motor of the present invention for ultra-precision rotation, it is possible to easily manufacture curved mirrors with high shape accuracy.
You can do that. □As described above, the present invention has two
A cylindrical electrostrictive element is laminated together to form a cylindrical electrostrictive element, which has a cylindrical electrostrictive element and a cylindrical electrostrictive element. Rin)
Outside the body element.

By moving one side of the block fixed around the circumference in a straight line, or by using a near motor, we can obtain a linear motor that has high precision and stable continuous motion at a constant speed.

[Brief explanation of the drawing]

Is Figure 1 I to I the conventional linear snow model? - In order to explain the operation in accordance with an example, Fig. 2 is a side view, Fig. 2 is an exploded perspective view of a linear motor according to an embodiment of the present invention. 4a-f are waveform diagrams for explaining the operation of the linear motor in FIG. 3, and FIG. 5 is a side view for explaining the operation of the linear motor according to the present invention. FIG. 6 is a perspective view showing an application example, and FIG. 6 is a sectional view of a main part of the configuration shown in FIG. 5. 1... Electrostrictive element, 2, 3... Clamp element, 4... Fixed stage, 6, 6... Bimorph type electrostrictive element, 7...・Fixed Glock, 8,
9... Clamp element, io・-=slide shaft, 11.12... Electrode, 13...
・Spindle, 14... Material to be cut, 15...
...Bite, 16.17...Linear motor,
18... Bimorph type electrostrictive element, 19...
... Clamp element, 20 ... Slide guide shaft, 21 ... Carriage, 22 ... Air bearing, 51.52 ... Electrostrictive element 〇 Name of agent Patent attorney Toshio Nakao and 1 other person 3rd
Figure 2-413- Figure 6 Procedural Amendment Document Showa Yu and I 1-7/9 1982 Patent Application No. 207809 2 Name of the invention Linear motor 3 Person making the amendment 11+ Relationship with f'i 1); Cow
Applicant: 1 Address: 1006 Kadoma, Kadoma City, Osaka Prefecture (582) Matsushita Electric Industrial Co., Ltd. Representative: Toshihiko Yamashita 4 Agent Address: 571 +Ji Address: 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Co., Ltd. Figure 2 inside Sangyo Co., Ltd.

Claims (1)

[Claims] (1) A cylindrical electrostrictive element that expands and contracts in the radial direction is arranged on the inner periphery of a ring-shaped element made by pasting two electrostrictive elements in opposite directions, and the ring-shaped element and the cylindrical electrostrictive element A linear motor, characterized in that the applied voltage is controlled to move either a shaft passing through the cylindrical electrostrictive element or a block disposed outside the ring-shaped element.