JPH01185175A - Mechanical amplifier mechanism - Google Patents

Abstract

PURPOSE:To eliminate a drift due to temperature change by constituting an apparatus by the use of a spring having an elongation due to thermal expansion equal to the variation due to thermal expansion of an arm tip. CONSTITUTION:A mechanical amplifier mechanism has a structure, where a pair of lever arms 4 respectively connected with the displacement transmission system 2 and base 3 facing each other of a piezoelectric element 1 and a spring 5 supported by said lever arms in the manner of being held between them are connected with each other. In consideration of thermal expansion coefficients of said lever arms 4 and spring 5, materials are combined with each other so that the variation due to thermal expansion of the tip of said lever arm 4 is equal to the elongation due to thermal expansion of the central part of said spring 5. Thus, a drift due to temperature change can be eliminated and the same correct output as that at an ordinary temperature can be obtained even if this apparatus is operated at a high temperature.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a mechanical amplification mechanism that fully amplifies and drives the motion of an electromechanical transducer, and in particular uses an electrostrictive or piezoelectric element as a drive source to amplify displacement. Concerning the structure of a mechanical amplification mechanism.

[Conventional technology]

An example of a conventional mechanical amplification mechanism of this type will be explained with reference to FIG. This is a multilayer piezoelectric element 1f that utilizes longitudinal effect strain: a mechanical amplification mechanism configured to be used as a drive source.
The piezoelectric element 10 has a structure in which a pair of lever arms 4' are respectively connected to a displacement transmission system 2' and a substrate 3' facing each other, and a spring 5 as a displacement transmission means supported by the lever arms 4' is connected. It has become. The material for parts other than the piezoelectric element 1 has an elastic modulus of 19,000 to 21.
．． OOOkgf/mm" and has a large S with good springiness.
US material was used. The shape of this mechanical amplification mechanism is 25 mm long, 32 mm wide, and 3 mm thick.

After heating this mechanical amplification mechanism to 60°C, it was cooled to room temperature and changes in shape were observed. As a result, when comparing the shape at room temperature and the shape at a high temperature of 60° C., the tip of the lever arm 4' expands outward A due to thermal expansion, and both ends of the spring 5 are pulled accordingly. This spring 5 also expands due to thermal expansion, but since the amount of expansion is smaller than the amount of change at the tip of the lever arm 4', the central portion of the spring 5, which is the output end, is retracted into the inside B.

[Problem that the invention seeks to solve]

In this way, the output performance of the mechanical amplification mechanism is easily affected by the initial deflection of the spring 5, so changes in the center of the spring 5 due to thermal expansion due to temperature changes are simply due to changes in the shape of the spring's initial deflection. As a result, the output performance will change. Note that the thermal expansion coefficient of SUB material such as 5US304 is about 10 to 17×10/°C.

This conventional mechanical amplification mechanism can be used in any shape with 5US3
Since it was made of 04 material and no consideration was given to thermal expansion, there was a drawback that the output end of the barb 5 changed when the temperature changed.

The object of the present invention is to eliminate such drawbacks and to create a complete mechanical amplification mechanism in which the drift due to temperature changes at the output end of the spring approaches zero by using materials with different coefficients of thermal expansion for the lever arm and the spring. It is about providing.

[Means for Solving the Problems] The configuration of the present invention includes two lever arms that transmit and amplify the expansion and contraction motion of an electrostrictive element or piezoelectric element, and a displacement amplifying means supported so as to be sandwiched between these lever arms. In the mechanical amplification mechanism having a spring, the lever arm and the spring are formed of a combination of materials such that the amount of change due to thermal expansion at the tip of the lever arm is equal to the amount of elongation due to thermal expansion at the center of the spring. It is characterized by

〔Example〕

Next, the present invention will be explained in detail with reference to the drawings.

FIG. 1 is a plan view of one embodiment of the present invention. This embodiment includes a pair of lever arms 4 connected to a displacement transmission system 2 and a substrate 3 facing each other of a piezoelectric element 1, and a spring 5 as a displacement transmission means supported between the lever arms 4.
It has a connected structure.

In this example, it is important to combine materials in consideration of the thermal expansion coefficients of the lever arm 4 and spring 5, and experiments were conducted using the combinations shown in Table 1 below.

Table 1 This mechanical amplification mechanism After heating to t-60'c, the sample was cooled to room temperature and changes in shape were observed.

FIG. 2 is a temperature characteristic diagram at the output end of the mechanical amplification mechanism in this experiment. As can be seen from the figure, 42
When used in Nie lever arms, there is no deformation due to temperature changes. Also, when used for Nov, Inv t-lever arm, it will deform to some extent, but the degree of deformation is similar to that of 5U83.
It was much smaller than 04.

FIG. 3 is a front view of the second embodiment of the present invention, and the shape of this mechanical amplification mechanism is 35 mm in length and 35 mm in width.

The thickness is 4 mm. FIG. 4 is a temperature characteristic diagram obtained by conducting an experiment similar to that of the first embodiment shown in FIG. In this embodiment, a pair of lever arms 9 are connected to a displacement transmission system 7 and a substrate 8 which face a piezoelectric element 60, and a spring 5 as a displacement transmission means is connected to the lever arms 9 so as to be sandwiched therebetween. It is a structure.

In this case as well, as can be seen from Fig. 4, the lever arm 9 is made of 42Ni, and the spring 5 is made of YNiC (thermal expansion coefficient 8.1X10
/C) When using t-, there is less deformation due to temperature changes, and the lever arm 9 is made of 5US304.

Spring 5 has 8US631 (thermal expansion coefficient 11JXIO-'/
Even when C) was used, there was little deformation due to temperature changes.

The amount of change due to thermal expansion at the tip of the lever arm 9 depends on the material of the lever arm and the shape of the mechanical amplification mechanism, but in the case of a mechanical amplification mechanism with a fixed shape, the material of the lever arm is determined first. A method of selecting a material for the spring 5 that has an elongation due to thermal expansion equal to the amount of change due to thermal expansion of the tip of the lever arm, and a method of selecting a material for the spring 5 that has an elongation due to thermal expansion equal to the amount of change due to thermal expansion of the spring. There is a method of selecting the material of the lever arm.

[Effects of the Invention] As explained above, the present invention is constructed with a spring having an elongation due to θ thermal expansion that is equal to the amount of change due to thermal expansion at the end of the arm, thereby preventing drift due to temperature changes even when operated at high temperatures. The effect is that the same output performance as at room temperature can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a front view of a mechanical amplification mechanism according to an embodiment of the present invention;
2 is a temperature characteristic diagram at the output end of the mechanical amplification mechanism of the embodiment shown in FIG. 1, FIG. 3 is a front view of the second embodiment of the present invention, and FIG. Temperature characteristic diagram, 5th
The figure is a front view illustrating a modification of a conventional mechanical amplification mechanism. l...Piezoelectric element, 2,7...Displacement transmission system, 3゜8...Substrate, 4,9...Lever arm, 5... ...Spring. Agent Patent Attorney Susumu Uchihara

Claims (1)

[Claims] In a mechanical amplification mechanism that includes two lever arms that transmit and amplify the expansion and contraction motion of an electrostrictive element or a piezoelectric element, and a spring that is a displacement amplification means that is supported so as to be sandwiched between these lever arms, the heat at the tip of the lever arm is A mechanical amplification mechanism characterized in that the lever arm and the spring are formed of a combination of materials such that the amount of change due to expansion is equal to the amount of elongation due to thermal expansion of the central portion of the spring.