JPS6326528A - Manufacture of angular velocity sensor - Google Patents

Abstract

PURPOSE:To manufacture a high-reliability, high-performance, and low-cost angular velocity sensor by arranging a couple of sensor elements in parallel to each other, and joining end parts of their piezoelectric elements by a metallic member. CONSTITUTION:A base member 5 and a support rod 4 are assembled previously. Then, the member 5 is fitted to the base fitting block 12 of a jig firstly, solder paste is applied to the tip of the support rod 4, and the metallic member 3 is inserted. Then the block 12 is fitted to a main jig. In this case, the member 5 is positioned by a rubber cushion 13. Then, extra solder or solder paste is applied to the joint parts of the sensor elements 1, 2, and 6 for the member 3, and they are fitted to the main jig, and set by suction 9, element pressers 10 and 11, etc. Then, the heating point of the member 3 is heated by a soldering iron or laser to perform solder joining. Thus, the element 1, 2, and 6 and member 3, and member 3 and support rod 4 are soldered by heating the member 3, thus assembling a high-accuracy turning-fork vibrator in a short time.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method of manufacturing an angular velocity sensor used in a gyroscope.

BACKGROUND ART In recent years, with the development of computer technology, products with many functions have been commercialized, and the demand for various sensors for this purpose has increased.

Applications of angular velocity sensors include navigation systems in electrical equipment, direction detection for robots, and stabilizer devices for drive devices, all of which will require small, high-performance sensors.

Conventionally, inertial navigation systems have mainly been used to determine the direction of moving objects such as airplanes and ships. Although this method can provide stable orientation, it is mechanical and therefore large-scale and costly, making it difficult to apply to consumer equipment where miniaturization is desired.

On the other hand, a vibrating gyroscope (Japanese Unexamined Patent Publication No. 59-55420) was devised that vibrates an object without using rotational force and detects the angular velocity from the Coriolis force that occurs when the angular velocity is generated. This vibration gyroscope can be thought of as a vibration sensor with a tuning fork structure, and is a promising technology that is small, low cost, and high performance.

An example of the conventional angular velocity sensor mentioned above will be described below with reference to the drawings.

4 and 5 show the structure of a conventional angular velocity sensor. In FIGS. 4 and 5, l is a drive piezoelectric element, 2 is a detection piezoelectric element, 3 is a metal member, and 4 is an elastic member (
5 is a base member, 6 is a joint, 7 is solder, and 8 is a conductive adhesive. A pair of sensor elements formed by orthogonally joining a drive piezoelectric element 1 and a detection piezoelectric element 2 at an angle of 90'' are arranged parallel to each other along the detection axis, and the ends of each drive piezoelectric element 1 are arranged parallel to each other along the detection axis. The parts are joined by a metal member 3, and the metal member 3 is supported by an elastic member (support rod) 4 to form a tuning fork structure.

The operation of the angular velocity sensor configured as above will be explained below.

The driving piezoelectric element on one side is driven at a certain frequency to cause the tuning fork to vibrate. The output of the other driving piezoelectric element generated by the tuning fork vibration is monitored and the tuning fork vibration level is kept constant by automatic gain adjustment. This causes acceleration to act on the sensing piezoelectric element, and the Coriolis force that occurs when angular velocity is applied causes mechanical strain on the sensing piezoelectric element.
A charge proportional to the angular velocity is generated.

Conventionally, this angular velocity sensor has been manufactured by soldering the driving piezoelectric element and the metal member, and then joining the metal member and the support rod using a thermosetting conductive adhesive.

Problems to be Solved by the Invention However, the above manufacturing method requires equipment and curing time for thermal curing.

In addition, if the piezoelectric element is greatly affected by heat, its characteristics will fluctuate and it will be necessary to leave the piezoelectric element for some time until its characteristics can be adjusted or inspected.

It had many problems, including problems with reliability due to variations in the adhesive strength of the conductive adhesive.

In view of the above problems, the present invention provides high accuracy and high reliability.

The present invention provides a method for manufacturing a high-performance, low-cost angular velocity sensor.

Means for Solving the Problems In order to solve the above problems, the angular velocity sensor of the present invention has the following features:
A pair of sensor elements, each consisting of a drive piezoelectric element and a detection piezoelectric element orthogonally joined to each other, are arranged parallel to each other, the ends of each piezoelectric element are joined to a metal member, and the metal member and the base member are connected to each other. This is an angular velocity sensor that has a tuning fork structure supported and joined by a support rod, and is constructed by a manufacturing method in which the piezoelectric element and the metal member, and the metal member and the support rod are simultaneously soldered and joined using an assembly jig.

Function: According to the present invention, a tuning fork structure can be assembled in a short time with little thermal influence and with high reliability and precision using the above-described manufacturing method.

EXAMPLE Hereinafter, a method of manufacturing an angular velocity sensor according to an example of the present invention will be described with reference to the drawings.

FIGS. 1 and 2 show an angular velocity sensor structure in an embodiment of the present invention. In FIG. 1, 1 is a drive piezoelectric element, 2 is a detection piezoelectric element, 3 is a metal member, 4 is an elastic member (support rod), 5 is a base member, 6 is a joint,
Reference numeral 7 denotes solder, and the driving piezoelectric element 1 and the metal portion t3 as well as the metal member 3 and the support rod 4 are joined by the solder 7.

The procedure for manufacturing the angular velocity sensor configured as above will be described below with reference to FIG. 3.

Figure 3 shows sensor elements 1, 2, 6, metal member 3, support rod 4, and base member 5 attached to a tuning fork assembly jig (partial view).
The base member 5 and support rod 4 are assembled in advance. First, install the base of the jig by a professional.
After attaching the base member 5 to the block 12, applying solder paste to the tip of the support rod 4 and inserting the metal member 3, the base is attached by attaching the block 12 to the jig body. At this time, the base member 5 is positioned by the rubber cushion 13. Next, apply preliminary solder or solder paste to the joint part of the orthogonally joined sensor element 1.2.6 with the metal member, and attach it to the jig body using suction 9 and element presser 10.11.
Parallelism and linearity can be set with high accuracy. Next, heat point A of the metal member with a soldering iron or
Since the heat capacity of the metal member 3 is small by heating with a laser or a light beam, heat is uniformly transmitted and solder bonding is possible.

As described above, according to this embodiment, a high-precision tuning fork vibrator can be assembled in a short time by simultaneously heating and soldering the sensor element and the metal member, and the metal member and the support rod. can.

Effects of the Invention As described above, the present invention provides a pair of sensor elements in which a drive piezoelectric element and a detection piezoelectric element are orthogonally joined to each other, and are arranged in parallel to each other, and the ends of each piezoelectric element are joined by a metal member. However, it is an angular velocity sensor in which a metal member and a base member are supported and joined by an elastic member, and the end of the piezoelectric element and the metal member, and the metal member and the elastic member are simultaneously soldered and joined to reduce heat influence. A tuning fork vibrator can be assembled in a short time. Because it is assembled while being set in a jig, the tuning fork vibrator has high accuracy in terms of parallelism and linearity, and also has excellent characteristics such as resonance impedance. In addition, since the metal member and support rod are not joined on the adhesive side, joint failures due to variations in adhesive strength are eliminated, and there is no need for equipment for curing or positioning jigs during curing. It is possible to manufacture angular velocity sensors with low cost, high reliability, and high performance.

[Brief explanation of the drawing]

FIG. 1 is a front view of an angular velocity sensor according to an embodiment of the present invention, FIG. 2 is a partial sectional view of FIG. 1, and FIG. FIG. 4 is a front view of a conventional angular velocity sensor, and FIG. 5 is a partial sectional view of FIG. 4. 9...Suction hole, 10...Detection element holder, 11...Driving element holder, 12...
・Base installation is block. Name of agent Patent attorney Toshio Nakao 1 person @ 2 Figure 7-1'E 9--51 Le

Claims (1)

[Claims] A pair of sensor elements, each consisting of a drive piezoelectric element and a detection piezoelectric element orthogonally joined to each other, are arranged parallel to each other, the ends of each of the piezoelectric elements are joined to a metal member, and the metal member and the base member are connected to each other. An angular velocity sensor having a tuning fork structure in which the piezoelectric element is supported and joined by an elastic member, and is characterized in that the end portion of the piezoelectric element and the metal member, and the metal member and the elastic member are simultaneously soldered and joined. A method of manufacturing an angular velocity sensor.