JP2000158338A - Detection method of wear state and center shift of grinding tool - Google Patents

Abstract

PROBLEM TO BE SOLVED: To precisely detect the wear state or center shift of a grinding tool for grinding a crystal element precisely. SOLUTION: In the detection of a center shift, by rotating a grinding tool 14 at every 90 deg., the moving distance until each position is brought into contact with a crystal element 12 is detected. Based on this moving distance, a center shift amount is detected and the correction of the center shift is carried out precisely. In the detection of a wear state, after grinding the crystal element 12 by a prescribed amount by moving the grinding tool 14 by an indication distance, the grinding tool 14 is returned back to an initial position and moved until the grinding tool 14 is brought into contact with the crystal element 12 (branch 24) again. By detecting this moving distance (contact distance), the difference between the indication distance and the contact distance is detected and when this difference is a prescribed amount or more, it is judged that the wear state of the grinding tool 14 is remarkable and the replacement of the grinding tool 14 is indicated on an indicator 22.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for detecting a wear state and misalignment of a grinding tool for grinding a crystal element for precisely correcting an unbalanced component of the oscillation frequency of a crystal element used as a tuning fork vibrator. About the method.

[0002]

2. Description of the Related Art A tuning fork type crystal resonator is used for a basic oscillator of an electronic timepiece. If there is an imbalance between the two branches of the tuning fork, the crystal oscillator fluctuates in oscillation frequency, and cannot generate a predetermined oscillation frequency.

One of the methods for correcting imbalance is a method by grinding. That is, the tuning fork branch is ground with high precision by a grinding tool, and the oscillation frequency is adjusted to a predetermined value.

In this case, the grinding tool deteriorates with time due to wear, and it becomes difficult to grind the quartz oscillator to a predetermined accuracy. Therefore, the grinding tool is replaced with a new one every predetermined number of work pieces.

Further, in order to prevent a reduction in grinding accuracy due to a misalignment of the grinding tool, the misalignment is visually corrected.

[0006]

However, if the grinding tool is replaced with a new one every time the number of workpieces is maintained in order to maintain the grinding accuracy, the grinding tool which has not reached the limit of use will also be replaced, resulting in waste. Occurs. In addition, it is not possible to cope with a sudden occurrence of a lack of a grinding tool.

Further, the grinding tool has a tool diameter of 2-3 m.
m, it was difficult to visually adjust the misalignment.

In view of the above facts, the present invention provides a grinding tool wear state and a misalignment detection method capable of detecting a grinding tool wear state or a misalignment with high accuracy in order to grind a crystal element with high accuracy. The task is to

[0009]

According to the first aspect of the present invention, there is provided a method of detecting a wear state of a grinding tool for grinding a quartz element by sliding a circumferential surface of the cylindrical element on the quartz element while rotating the cylindrical body. A first step of grinding the crystal element by a predetermined amount by moving the rotated grinding tool from the initial position to the designated position; a second step of returning the grinding tool to the initial position after the grinding is completed; A third step of moving the grinding tool from the initial position to a position in contact with the crystal element with respect to the set crystal element and detecting a contact distance from the initial position to a position in contact with the crystal element; A fourth step of detecting a wear state of the grinding tool based on a difference between a designated distance to a position and the contact distance.

The operation of the first aspect of the present invention will be described.

When the grinding tool moves to a designated position (designated distance), the crystal element is ground by a predetermined amount. That is, the designated distance includes the distance from the grinding tool to the crystal element and the grinding amount (distance) of the crystal element. By moving the grinding tool to the designated position, the crystal element is ground by a predetermined amount. .

However, when the grinding tool is worn and the sharpness is reduced, the movement of the grinding tool causes the crystal element to be pressed and bent (see FIG. 3), and the movement amount of the grinding tool and the grinding amount of the crystal element correspond to each other. Disappears. As a result,
The amount of grinding of the crystal element is smaller than the amount of movement of the grinding tool (the planned amount of grinding of the crystal element).

The state of wear of the grinding tool which results in such a result is detected as follows.

First, the grinding tool is returned to the initial position. Subsequently, the grinding tool is brought close to and brought into contact with the ground crystal element. As a result, it is detected that the excitation voltage of the crystal element has changed and the grinding tool has contacted the crystal element.
The wear state is detected based on the difference between the contact distance from the initial position to the contact and the designated distance. In other words, it is possible to detect the progress of abrasion based on the difference in grinding amount (difference in distance).

According to a second aspect of the present invention, there is provided a method for correcting a misalignment of a grinding tool for grinding a quartz element by sliding a circumferential surface of the cylindrical body on the quartz element while rotating the cylindrical body. A first step of exciting the crystal tool, a second step of moving the grinding tool from the initial position to a position in contact with the excited crystal element, and detecting a moving distance from the initial position to a position in contact with the crystal element, and a grinding tool Is returned to the initial position, the grinding tool is rotated by a predetermined angle, and a third step of detecting a moving distance from the initial position to a position in contact with the crystal element in the same manner as in the second step, and A fourth step of detecting the moving distance by repeating the third step until the circumferential surface makes one revolution, and detecting the amount of misalignment of the grinding tool based on each moving distance detected in the second step and the third step; And Characterized in that it obtain.

The operation of the second aspect will be described.

When the grinding tool comes into contact with the excited crystal element, it is detected that the excitation voltage of the crystal changes and the grinding tool comes into contact with the crystal element. Therefore, it is possible to detect the moving distance of the grinding tool from the initial position to the position where it contacts the crystal element. The grinding tool is rotated by a predetermined angle around the rotation axis of the grinding tool, and the movement distance until each part on the circumferential surface contacts the crystal element is detected in the same manner as described above. Based on each of the moving distances detected in this manner, it is possible to detect which part of the circumferential surface of the grinding tool is displaced with respect to the rotation axis in the circumferential direction, that is, the amount of misalignment. it can.

By correcting the misalignment of the grinding tool so as to reduce the amount of misalignment, the crystal element can be accurately ground.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A grinding apparatus to which a method for detecting a wear state and a misalignment of a grinding tool according to an embodiment of the present invention is applied will be described in detail with reference to FIGS.

As shown in FIG. 1, the grinding apparatus 10 has a cylindrical grinding tool 14 for grinding a tuning-fork type crystal element 12.
A driving unit 16 for moving the grinding tool 14 about the rotation axis 15 while moving the grinding tool 14 toward and away from the crystal element 12 (in the direction of the arrow X);
An oscillation circuit 18 for exciting the vibration element 2, a movement distance detection circuit 20 for detecting an amount of movement of the grinding tool 14 based on a change in the frequency of the crystal element 12 detected by the oscillation circuit 18 and an input of the driving means 16, A display unit 22 for displaying the wear state of the tool 14 and the amount of misalignment is provided.

The crystal element 12 is branched into two branches 24 and 26 each having an H-shaped tip.
It is important that the four and 26 are balanced to generate a predetermined frequency. Therefore, if the branches 24 and 26 are unbalanced, one of the branches is ground to correct the unbalance.

A method for detecting a misalignment and a worn state of the grinding tool 14 in the grinding apparatus 10 used for correcting the imbalance will be described.

First, a method of detecting a misalignment of the grinding tool 14 will be described.

In this case, the driving tool 16 moves the grinding tool 14 from the initial position toward the crystal element 12 in the direction of the arrow XL while the crystal element 12 is excited by the oscillation circuit 18. The portion A of the grinding tool 14 (the portion on the circumferential surface on the line connecting the rotating shaft 15 and the branch 24 of the crystal element 12 in the direction of the arrow X) abuts on the branch 24 of the crystal element 12, whereby the crystal element 12 The frequency of changes. By detecting this change with the oscillation circuit 18, the movement distance detection circuit 20 detects that the grinding tool 14 has contacted the branch 24 of the crystal element 12, and
The drive with stops, detects the moving distance X _A grinding tool 14 (see FIG. 2).

Subsequently, the driving means 16 is driven to return the grinding tool 14 to the initial position, and is rotated 90 degrees counterclockwise about the rotation shaft 15. The part B of the grinding tool 14 is arranged to face the branch 24. Grinding tool 14 as before
It is moved toward the branch 24, detects the moving distance X _B to abut to the branch 24 from the initial position.

Thereafter, the grinding tool 14 is similarly rotated by 90 degrees counterclockwise to detect the moving distances X _C and X _D of the parts C and D of the grinding tool 14.

As described above, by detecting the moving distances X _{A to} X _D , the grinding tool 14 based on the branch 24 is detected.
(Distances A to D) can be detected. The misalignment of the grinding tool 14 is corrected based on the numerical data.

For example, if X _A -X _C = d> 0, it indicates that the part A is deviated to the rotating shaft 15 side.
The part A is separated from the rotation shaft 15 by two. As described above, the misalignment can be corrected more accurately than the visual correction. Therefore, the crystal element 12 can be ground with high accuracy.

Next, a method of detecting a wear state will be described.

First, the grinding tool 14 rotated by the driving means 16 is moved by a designated distance (feed amount) X ₁ set in advance based on the grinding amount, and is brought into sliding contact with the excited crystal element 12. As a result, the branch 24 of the crystal element 12 is ground by a predetermined amount.

However, when the grinding tool 14 is worn, the sharpness is reduced, the branch 24 is pressed, and is bent by the distance D in the direction of the arrow X (see FIG. 3). That is, the grinding tool 14 contacts the crystal element 12 and the arrow X
Despite moving in the direction to the indicated position, the distance D
A situation occurs in which the grinding amount is reduced by the amount.

Then, after the grinding is completed, the grinding tool 14 is returned to the initial position by the driving means 16, and the grinding tool 1 is returned to the initial position.
4 is moved in the X ₁ direction. As a result, the grinding tool 14
The oscillation circuit 18 detects from the change in the frequency that the abutment has come into contact with the excited branch 24 of the crystal element 12. Moving distance detecting circuit 20 by the detection, stops the driving of the driving means 16, the moving distance (hereinafter, referred to as contact distance) to detect the X _2. In moving distance detecting circuit 20 detects a difference between the instructed distance X ₁ and the contact distance X _2, it determines the difference between the wear of the grinding tool 14 is remarkable in the case of more than the predetermined value, exchanging the grinding tool 14 What to do is displayed on the display unit 22.

As described above, the grinding device 10 accurately detects the amount of misalignment of the grinding tool 14 before grinding. Therefore, by correcting the misalignment of the grinding tool 14 based on the misalignment amount, the crystal element 12 can be ground with high accuracy.

Further, immediately after the grinding, the actual grinding amount is detected by the moving distance (contact distance X ₂ ) of the grinding tool 14, and the wear state of the grinding tool 14 is determined based on the difference from the designated distance X ₁ . Thus, the wear state of the grinding tool 14 can be detected for each processing, so that the grinding tool 14 can be used to its limit. In addition, it is possible to quickly cope with a chipping of the grinding tool 14 which occurs suddenly.

[0035]

According to the first aspect of the present invention, the wear state of the grinding tool can be detected for each grinding, so that the grinding tool can be used up to its use limit. In addition, since it is possible to reliably detect a material that has reached the usage limit, it is possible to prevent a reduction in grinding accuracy of the crystal element.

According to the second aspect of the present invention, since the amount of misalignment can be accurately detected, the misalignment of the grinding tool can be corrected based on the amount of misalignment, and the crystal element can be ground with high accuracy.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a grinding device according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram of a method for detecting a misalignment of a grinding tool according to an embodiment of the present invention.

FIG. 3 is an explanatory diagram of a state of bending of a crystal element during grinding.

FIG. 4 is an explanatory view of a method for detecting a wear state of a grinding tool according to an embodiment of the present invention.

[Explanation of symbols]

10 grinding apparatus 12 crystal element 14 Grinding tool X ₁ instruction distance X ₂ abutting distance X _A to X _D moving distance

Claims (2)

[Claims] 1. A method for detecting a wear state of a grinding tool for grinding a crystal element by sliding a circumferential surface on the crystal element while rotating a cylindrical body, comprising: A first step of grinding the crystal element by a predetermined amount by moving the grinding tool from the initial position to a designated position after the grinding, and a second step of returning the grinding tool to the initial position after the grinding is completed. A third step of detecting the contact distance from the initial position to the position contacting the crystal element by moving the contact position to the crystal element and detecting the contact distance from the initial position to the designated position; And a fourth step of detecting a wear state of the grinding tool on the basis of: a method of detecting a wear state of the grinding tool. 2. A method for correcting misalignment of a grinding tool for grinding a crystal element by sliding a circumferential surface on the crystal element while rotating a cylindrical body, comprising: a first step of exciting the crystal element. A second step of moving the grinding tool from the initial position to a position in contact with the excited crystal element and detecting a moving distance from the initial position to a position in contact with the crystal element; and after returning the grinding tool to the initial position. A third step of rotating the grinding tool by a predetermined angle and detecting a moving distance from an initial position to a position in contact with the crystal element in the same manner as in the second step; and until the circumferential surface of the crystal element makes one revolution. A fourth step of detecting a moving distance by repeating the third step, and detecting an amount of misalignment of the grinding tool based on each moving distance detected in the second step and the third step. To be Misalignment detection method of the cutting tool.