JPS59148418A - Method for adjusting frequency of piezoelectric tuning fork - Google Patents

Abstract

PURPOSE:To eliminate the need for clamping of tuning fork oscillator at cutting and to automate the frequency adjustment by cutting a tip corner of an oscillating chip of a tuning fork oscillator by a rotary grinder in the broadwise direction of the oscillating chip. CONSTITUTION:The specific oscillating frequency of the tuning fork oscillator 5 finished for assembling is measured and the deviation between the measuring value of the specific oscillating frequency and the objective specific oscillating frequency is obtained. Then, whether this deviation is within the permissible value or not is discriminated and when the deviation is at the outside of the permissible range, a rotary grinder rotating in the arrow Ar2 is contacted to the tip corner 11 of oscillating chips 6, 7 of the tuning fork oscillator 5, said tip corner 11 is cut as shown in alternate long and two short dashes lines in the broadwise direction of the oscillating pieces 6, 7 and this work is continued until the tip corner reaches within the said permissible range.

Description

[Detailed description of the invention] Technical field The present invention relates to a method for adjusting the frequency of a piezoelectric tuning fork.

BACKGROUND ART In general, a piezoelectric tuning fork has a ground terminal 2, an input terminal 3, and an output terminal 4 attached to a base 1 made of an insulating resin by insert molding or press-fitting, as shown in FIGS. 1 and 2. A tuning fork vibrator 5 is spot welded to the ground terminal 2, and electrodes of piezoelectric elements 8 and 9 (not shown) are attached to the vibration nodes of the vibrating pieces 6 and 7 of the tuning fork vibrator 5, respectively. are soldered to the input terminal 3 and output terminal 4, respectively.

In order to adjust the natural vibration frequency of the piezoelectric tuning fork having the above configuration, conventional methods have been used to prevent the tuning fork vibrator 5 from deforming, the piezoelectric elements 8 and 9 from being cranked, and the contact portion from being strained. The tuning fork vibrator 5 is clamped and its vibrating piece 6 is
, 7'' and move the file in the direction of arrow Ar1 in FIG. This was done by grinding to the position shown in .

By the way, when the natural vibration frequency of the piezoelectric tuning fork is adjusted as described above, the tuning fork vibrator 5 is clamped and the vibrating piece 6,
After grinding 7, the clamp of the tuning fork vibrator 5 is released and the frequency is measured. If the measured frequency is not within the allowable range, the above clamping and grinding must be repeated again, and the natural vibration frequency The adjustment was very troublesome.

Purpose of the Invention The present invention has been made in view of the above-mentioned circumstances in the conventional frequency adjustment method of a piezoelectric tuning fork, and its purpose is to move the tip corner of the vibrating piece of a tuning fork vibrator in the middle direction of the vibrating piece with a rotating grindstone. By grinding the piezoelectric tuning fork, it is possible to eliminate the need for clamping when grinding the tuning fork vibrator and to automate the frequency adjustment of the piezoelectric tuning fork.

- Second gist of moxibustion The present invention can be summarized as a method for adjusting the frequency of a piezoelectric tuning fork, in which a rotary grindstone is applied to the tip coker of a vibrating piece of a tuning fork vibrator to grind the vibrating piece inward.

Example Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

FIG. 3 shows an embodiment in which the present invention is applied to a piezoelectric tuning fork having the configuration shown in FIGS. 1 and 2.

In the present invention, first, the assembled tuning fork vibrator 5 is
The natural vibration frequency of is measured, and the deviation between the measured natural vibration frequency and the target natural vibration frequency is determined. Next, it is determined whether or not this deviation is within a preset tolerance range, and if this deviation is outside the tolerance range, the tip corner portion 11 of the vibrating piece 6°7 of the tuning fork vibrator 5 is marked with arrow Ar2. Apply the rotary grindstone 12 that rotates in the direction, and
1 is ground in the l] direction of the vibrating pieces 6 and 7 as shown by the two-dot chain line. Thereafter, the measurement and grinding are performed until the deviation falls within the allowable range.

More specifically, the grinding of the vibrating pieces 6 and 7 is controlled by a computer so that the deviation between the measured value of the natural vibration frequency of the assembled tuning fork vibrator 5 and the target natural vibration frequency falls within an allowable range. Next, the rotation speed of the rotary grindstone 12 and the contact time between the vibrating piece 62.7 and the rotary grindstone 12 are controlled to grind the corner portion 11 of the vibrating piece 6.7.

If the vibration frequency of the tuning fork vibrator 5 is adjusted as described above, force will be applied from the rotating grindstone 12 to the vibrating piece 6.7 of the tuning fork vibrator 5 in the direction of the center thereof. , the distance between the vibrating pieces 6 and 7 will not change or deform, and the bonding state of the piezoelectric elements 8 and 9 will not deteriorate. Therefore, there is no need to clamp the tuning fork vibrator 5, and the vibration frequency of the tuning fork vibrator 5 can be automatically adjusted by computer control.

It goes without saying that the present invention can be applied to piezoelectric tuning forks other than those shown in FIGS. 1 and 2.

Effects of the Invention As is clear from the detailed explanation, the present invention has the following effects:
When adjusting the frequency of a piezoelectric tuning fork, the tip corner of the vibrating piece of the tuning fork vibrator is ground in the width direction of the vibrating piece using a rotating grindstone, which eliminates the need to clamp the tuning fork vibrator, making it possible to adjust the tuning fork vibrating element, which was previously difficult. The frequency adjustment of the vibrator can be automated.

[Brief explanation of drawings]

FIG. 1 is a plan view showing an example of the structure of a piezoelectric tuning fork, FIG. 2 is a front view of the piezoelectric tuning fork shown in FIG. 1, and FIG. 3 is an explanatory diagram of an embodiment of the present invention. 1... Base, 2... Earth terminal, 3... Input terminal, 4... Output terminal, 5... Tuning fork vibrator, 6, 7...
... Vibrating piece, 8.9... Piezoelectric element, 11... Corner part, 12... Rotating grindstone. Patent applicant Murata Manufacturing Co., Ltd. Agent
Patent attorney Aoyama Aoyama and 2 others Figure 1 Figure 3 Figure 2

Claims (1)

[Claims] (1) A method for adjusting the frequency of a piezoelectric tuning fork, in which a rotary grindstone is applied to the tip corner of a vibrating piece of a tuning fork vibrator, and the vibrating piece is ground in the middle direction.