JPH0244529Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a piezoelectric bimorph device that applies expansion and contraction due to the inverse piezoelectric effect of a piezoelectric material.

Piezoelectric actuators can be categorized from a structural perspective into two types: piezoelectric bimorphs, which have a lateral effect that has the function of expanding displacement, and lateral layer piezoelectric displacement elements, which use vertical effects to increase displacement per unit length. .

As mentioned above, the piezoelectric bimorph has an expansion mechanism element in its structure itself, and generates a bending displacement at the tip that is hundreds of times larger than the elongation due to the lateral effect of the piezoelectric plate that makes up the piezoelectric plate. Various applications are being considered as actuators.

However, a drawback of the piezoelectric bimorph is the instability of the tip position. This is because the structure itself is a cantilever structure, and the disadvantage is that the displacement gradually increases not only due to external mechanical vibrations but also due to temperature changes, or in the case of continued voltage application related to piezoelectric displacement. phenomenon is also recognized.

When using a piezoelectric bimorph as a driving source, the tip position changes depending on the temperature.
This will lead to various kinds of performance deterioration, but in reality, since the structure is a laminate made of several kinds of materials, it is inevitable that the tip will bend due to the same effect as bimetal.

In view of these points, the present invention has a piezoelectric bimorph whose fixed part has a seesaw structure, and both sides of the fulcrum are tightened with screws having different coefficients of thermal expansion.
The angle of the fixed part changes due to the difference in the coefficient of thermal expansion of the fixed screw due to temperature changes,
As a result, the main purpose is to propose a bimorph device that can compensate for fluctuations due to temperature changes in the tip position of the bimorph and improves the temperature stability of the tip position.

An embodiment of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a diagram showing the basic structure of the present invention.
A protrusion 4 is provided on the lower side of the fixing part 2 for fixing the bimorph element 1. Therefore, when fixing part 2 is fixed on base plate 6 with screws 3,
The fixed part 2 of the bimorph element 1 has a swingable structure that is tightened with four screws 3 using the protrusion 4 as a fulcrum.

That is, in FIG. 2, due to the difference in the amount of expansion and contraction of the screws 3 on both sides of the fulcrum of the protrusion 4, the attachment angle of the fixing part 2 of the bimorph element 1 changes, and the position of the tip of the bimorph element 1 changes. gradually changes up and down.

To show this specifically, the distance between the front and rear screws 3 across the protrusion 4 is 10 mm, and the effective length of the screw 3 is 10
mm, the distance from the protrusion 4 to the tip of the bimorph element 1 is 55 mm, the front screw 3 is soft iron, and the rear screw 3 is brass, then the amount of displacement of the tip of the bimorph element 1 due to a temperature change of 30°C is The difference in expansion and contraction of the screw 3 of the fixing part 2 is Δl = 10mm x (190-115) x 10 ^-7 /℃ x 30℃ = 0.00225mm The ratio expanded by the seesaw structure is , 55mm÷5mm=11 (times) Therefore, the amount of displacement △l′ at the tip of bimorph element 1 is: △l′=△l×11=0.0245mm Actually, the degree of tightening of screw 3, the fixed part 2
By appropriately selecting the material and tightening level of the screws 3 before and after the fulcrum, the tip of the bimorph element 1 itself can be compensated for by changing its tip due to changes in temperature. This can be offset by adjusting the angle of the fixed part. Therefore, the position of the tip of the bimorph element 1 can be made immovable against temperature changes, and extremely stable operation can be achieved.

As described above, according to the present invention, the fixed part of the piezoelectric bimorph has a swing structure, and in the structure in which both sides of the swing fulcrum are tightened with screws, the screws are made of materials with different coefficients of thermal expansion, and Since the structure is configured such that fluctuations in the position of the bimorph tip according to temperature changes can be adjusted to a constant level, the tip position of the bimorph element 1, which has conventionally been unstable due to temperature, is stabilized, so that optical communication is improved. It can be used in all application fields of piezoelectric bimorphs, such as related adjustment mechanisms, piezoelectric relays, hard processing mechanisms, etc., and is an extremely valuable device from a technical standpoint.

[Brief explanation of drawings]

1 and 2 are a perspective view and a side view showing an embodiment of the present invention. 1... Bimorph element, 2... Fixed part, 3...
...screw, 4...protrusion.

Claims (1)

[Scope of utility model registration request] In a structure in which the fixed part of the piezoelectric bimorph has a swinging structure and is fixed by tightening screws on both sides of the swinging fulcrum, the screws are made of materials with different coefficients of thermal expansion, and the position of the tip of the bimorph in response to changes in environmental temperature. A bimorph device characterized by being able to adjust fluctuations to a constant value.