JPH03150915A - Vibrator - Google Patents

Abstract

PURPOSE:To improve the characteristic such as a drift due to a temperature change by adhering a piezoelectric element to at least 3 side faces in a polygonal shape vibrator and forming the position of at least one end of one piezoelectric element and other piezoelectric element to be deviated when viewing from a lengthwise direction of the vibrator. CONSTITUTION:A vibrator 10 includes a polygonal shape made of a constant elastic metallic material such as a regular triangular shaped vibrator 12, and piezoelectric elements 14a-14c are adhered in the center of 3 side faces of the vibrator 12 respectively. Since the length of the piezoelectric element 14a in the lengthwise direction of the vibrator 12 is formed shorter than the length of the other two piezoelectric elements 14b, 14c, the vibrator 12 is bent in the vibrator 10 in a direction nearly orthogonal to a face with the piezoelectric element 14a adhered thereon due to temperature change. That is, distortion such as bent or twist caused due to the difference from the thermal expansion coefficient between the vibrator 12 and the piezoelectric elements 14a-14c is oriented in one direction and the distortion in other directions is relaxed. Thus, the characteristic such as a drift due to temperature change is improved.

Description

[Detailed Description of the Invention] (Industrial Application Field) This invention relates to a vibrator, and in particular, a piezoelectric element is bonded to a vibrating body made of a constant elastic metal material, and is used in devices that utilize vibration, such as a vibrating gyro. Regarding the vibrator used.

(Prior Art) FIG. 2 is a perspective view showing an example of a conventional vibrator. This vibrator l includes a regular triangular prism-shaped vibrating body 2 made of a constant-elasticity metal material such as Elinva, and strip-shaped piezoelectric elements 3a, 3b, and 3c are arranged at the center of three side surfaces of the vibrating body 2. Each is attached with adhesive. In this case, an epoxy adhesive is used as the adhesive, and the adhesive is
Each of the piezoelectric elements 3a to 3C is bonded to the vibrating body 2 by curing at a temperature of 80 to 200°C.

(Problem to be Solved by the Invention) However, in the above-mentioned vibrator 1, the thermal expansion coefficient of the vibrating body 2 made of a constant elastic metal material is approximately 8 to 10×10-'/l'.
The coefficient of thermal expansion of the piezoelectric elements 3a to 3c is approximately 2 to 4.
X 10-b/'C, and due to differences in their thermal expansion coefficients, errors in the processing accuracy of the vibrating body, errors in the shape of the piezoelectric element, deviations in the bonding position, etc., when the piezoelectric element is bonded and returned to room temperature. , distortion such as warping or twisting occurs in the longitudinal center portion of the vibrating body 2. This strain changes with changes in ambient temperature. Therefore, the characteristics of this vibrator, such as drift, change due to temperature changes, making it unstable.

Therefore, the main object of the present invention is to provide a vibrator whose characteristics are stable against temperature changes.

(Means for Solving the Problems) The present invention includes a polygonal prism-shaped vibrating body made of a constant-elasticity metal material, and piezoelectric elements bonded to at least three sides of the vibrating body. Look in the direction,
This is a vibrator in which at least one end of one piezoelectric element and another piezoelectric element are formed at shifted positions.

Note that in order to form at least one end of one piezoelectric element and another piezoelectric element at a shifted position when viewed in the longitudinal direction of the vibrating body, it is necessary to The lengths in the directions may be different, or the lengths of the piezoelectric elements may be made the same, and one piezoelectric element may be offset from the other piezoelectric elements in the longitudinal direction of the vibrating body and bonded. good.

(Function) In this vibrator, the vibrating body bends in a direction substantially perpendicular to the surface to which one piezoelectric element is bonded due to a temperature change. That is, distortions such as warping and twisting caused by the difference in thermal expansion coefficients between the vibrating body and the piezoelectric element are directed in one direction, and distortions in other directions are alleviated.

(Effects of the Invention) According to the present invention, the strain caused by temperature change is directed in one direction, and the strain in other directions is relaxed, so that characteristics such as drift due to temperature change are improved.

The above objects, other objects, features and advantages of the present invention will become more apparent from the following detailed description of embodiments with reference to the drawings.

(Embodiment) Fig. 1A is a plan view showing an embodiment of the present invention, Fig. 1B is a side view thereof, and Fig. 1C is a line I in Fig. 1B.
It is a sectional view at C-1'C.

The vibrator 10 includes a vibrating body 12 in the shape of a regular triangular prism, for example, made of a constant elastic metal material such as Erinba.

Piezoelectric elements 14a, 14b, and 14C are bonded to the centers of the three side surfaces of the vibrating body 12, respectively, by curing, for example, an epoxy resin adhesive at about 180 to 200°C. That is, the piezoelectric elements 14a, 1
4b and 14c are piezoelectric layers 16a and 16b, respectively.
and electrodes 18a, 18b and 18 on the amphibious surface of 16c.
c and electrodes 20a, 20b, and 20c, respectively, and one of the electrodes 18a to 18C is connected to the vibrating body 1.
It is glued to 2.

Furthermore, in this embodiment, in particular, one piezoelectric element 14a is formed to have a shorter length in the longitudinal direction of the vibrating body 12 than the other two piezoelectric elements 14b and 14C.

Therefore, in this vibrator 10, piezoelectric elements 14a to 1
4c is bonded to the vibrating body 12 and then returned to room temperature, it bends from the state shown by the dashed line in FIG. The surfaces to which piezoelectric elements 14b and 14C are bonded are deformed approximately symmetrically. The degree of this deformation varies depending on changes in ambient temperature, but since the surface to which the piezoelectric element 14a is bonded is particularly greatly deformed, the piezoelectric elements 14b and 14
The surface to which C is adhered always deforms approximately symmetrically. Therefore, in this vibrator 10, for example, the piezoelectric element 14a
If the piezoelectric elements 14b and 14c are used for feedback or driving and the other piezoelectric elements 14b and 14c are used for driving or feedback, the vibration characteristics do not change much with respect to temperature changes. That is, this vibrator 10 has good characteristics such as drift with respect to temperature changes.

Note that in order to use this vibrator 10 as a vibrating gyro, a piezoelectric element 14 used for driving or feedback is required.
What is necessary is to measure the voltage generated between b and 14C. This is because the voltage generated between piezoelectric elements 14b and 14C is
This is because when the vibrator 10 is rotated around its axis, the rotational angular velocity changes depending on the rotational angular velocity.

In the above embodiment, one piezoelectric element is formed shorter than the other piezoelectric elements when viewed in the longitudinal direction of the vibrating body, but conversely, one piezoelectric element may be formed longer than the other piezoelectric elements. In this case, the direction in which the vibrator deforms due to temperature changes is simply opposite to that of the above embodiment. Alternatively, the piezoelectric elements may be formed to have the same size, and one piezoelectric element may be offset from the other piezoelectric elements in the longitudinal direction of the vibrating body and then bonded.

Further, in the above embodiment, the vibrating body is formed in the shape of a regular triangular prism, but the vibrating body may be formed in another polygonal prism shape. In this case, piezoelectric elements may be bonded to at least three side surfaces of the vibrating body, and at least one end of one piezoelectric element and another piezoelectric element may be formed at offset positions when viewed in the longitudinal direction of the vibrating body.

[Brief explanation of the drawing]

1A is a plan view showing one embodiment of the present invention, FIG. 1B is a side view thereof, and FIG. 1c is a line I in FIG. 1B.
It is a sectional view in C-IC. FIG. 2 is a perspective view showing a conventional vibrator. In the figure, 10 is a vibrator, 12 is a vibrator, 14a, 1
4b and 14C indicate piezoelectric elements. Figure 1A 0

Claims (1)

[Scope of Claims] A polygonal prism-shaped vibrating body made of a constant-elasticity metal material, and piezoelectric elements bonded to at least three side surfaces of the vibrating body, wherein one of the piezoelectric elements is bonded to at least three side surfaces of the vibrating body, and A vibrator in which at least one end of a piezoelectric element and another piezoelectric element are formed at offset positions.