JP2001349721A - Shape measuring method and apparatus for hole - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a shape measuring method and apparatus for a hole capable of measuring the shapes of various holes. SOLUTION: In the measuring apparatus 10 of the invention, an arm 36 is lowered to insert a measuring ball 30 in a hole 22A of a work 22, and the measuring ball 30 is lowered along the direction of depth of the hole 22A. Back pressure of compressed air is detected in plural portions by an A/E converter 18. The detected values are compared with a reference value of a master by control part 20 and converted to the inside diameter of the hole 22A.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for measuring the shape of a hole formed on a workpiece.

[0002]

2. Description of the Related Art An air micrometer is one of measuring devices for measuring the shape of a hole. A conventional air micrometer inserts a measuring head into a hole, injects compressed air from a nozzle of the measuring head toward a wall surface of the hole, and detects a back pressure of the nozzle. Since the back pressure of the nozzle depends on the distance between the inner wall of the hole and the nozzle, the detected value can be converted into the inner diameter of the hole by comparing it with a master reference value obtained in advance. The conventional air micrometer can determine the shape of the hole by continuously measuring the inner diameter while moving the measuring head into and out of the hole.

[0003]

However, the conventional air micrometer cannot measure the shape of the bent or curved hole because the measuring head cannot be put in and out of the bent or curved hole.

The present invention has been made in view of such circumstances, and has as its object to provide a hole shape measuring method and apparatus capable of measuring various hole shapes.

[0005]

According to a first aspect of the present invention, there is provided a shape of a hole for obtaining the shape of the hole by measuring an inner diameter of the hole at a plurality of positions along a depth direction of the hole. A measuring method, wherein a float is inserted into a hole to which a fluid is supplied, and a back pressure when the fluid passes through a gap between the inner wall of the hole and the float while moving the float along a depth direction of the hole. , The flow rate or the drag received by the float is detected at a plurality of locations, and the detected value is compared with a reference value to convert the detected value into the inner diameter of the hole.

According to a second aspect of the present invention, there is provided a hole shape measuring apparatus for measuring the inner diameter of a hole at a plurality of positions along a depth direction of the hole to obtain the shape of the hole. Fluid supply means for supplying a fluid to the hole, a float inserted into the hole, a moving means for moving the float along a depth direction of the hole, and the fluid removes a gap between an inner wall of the hole and the float. Back pressure when passing, flow rate, or detecting means for detecting the drag received by the float at a plurality of locations, and a converting means for converting the detected value detected by the detecting means to a reference value and converting the detected value into the inner diameter of the hole, It is characterized by having.

According to the first or second aspect of the present invention, the back pressure, the flow rate, and the drag received by the float are detected at a plurality of locations while the float is inserted and moved in the hole to which the fluid is supplied. Can be measured at multiple locations in the depth direction of the hole. Thereby, the shape of a hole having a non-uniform diameter, for example, a tapered hole can also be measured.

According to a third aspect of the present invention, there is provided a hole shape measuring method for obtaining a hole shape by measuring a center line of the hole, wherein a float is inserted into the hole to which fluid is supplied. Then, detecting the position of the float at a plurality of positions while moving the float along the depth direction of the hole, obtaining a center line of the hole from the detected value, and acquiring a shape of the hole based on the center line. It is characterized by.

According to a fourth aspect of the present invention, there is provided a hole shape measuring device for obtaining a hole shape by measuring a center line of the hole, the fluid supplying a fluid to the hole. Supply means, a float inserted into the hole, moving means for moving the float along the depth direction of the hole, and position detecting means for detecting the position of the float at a plurality of locations, And

According to the third or fourth aspect of the present invention, when the float is inserted into the hole to which the fluid is supplied, the float moves to the center of the hole due to the automatic centripetal action. Coincides with the center line of. Therefore, the center line of the hole can be obtained by detecting the position of the float at a plurality of positions.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a method and an apparatus for measuring the shape of a hole according to the present invention will be described below with reference to the accompanying drawings.

FIG. 1 shows a measuring apparatus 10 according to a first embodiment.
FIG. 3 is a block diagram showing the configuration of FIG. The measuring device 10 is a device that measures the inner diameter of the hole 22A of the work 22 at a plurality of locations in the axial direction of the hole 22A.

As shown in FIG. 1, compressed air supplied from an air source 12 is dust-removed by a filter 14 and adjusted to a constant pressure by a regulator 16.
The air is supplied to the air supply path 28B in the measurement table 28 through the throttle provided in the (air / electric converter) through the connector 33.

On the upper surface of the measuring table 28, there is formed a supply port 28A communicating with an air supply passage 28B.
2 is placed. A hole 22A is formed in the work 22, and the hole 22A communicates with the supply port 28A. An air leakage prevention seal (O-ring) 34 is provided around the supply port 28A. The air leakage prevention seal 34 prevents air from leaking from a gap between the measuring table 28 and the work 22. Thereby, the compressed air supplied to the air supply path 28B is injected from the supply port 28A to the hole 22A without leaking.

The compressed air injected into the hole 22A
It is blown out through a gap between the inner wall of A and the measuring ball (corresponding to a float) 30. The A / E converter 18 converts the pressure at this time into an electric signal by a built-in bellows and a differential transformer, and outputs the electric signal to the control unit 20. When the diameter of the hole 22A is different, the pressure slightly changes, and the control unit 20 calculates the inner diameter of the work 22 based on the changed electric signal, as described later, and transmits the calculated data to a monitor of the control unit 20, for example. To be displayed.

The measuring ball 30 is made of ceramic, resin,
It is formed into a sphere with high processing accuracy using materials such as steel and light alloys. As shown in FIG. 2, the diameter d of the measuring sphere 30 is
It is set according to the inner diameter (minimum diameter if the inner diameter is not constant) D of the hole 22A to be measured and the required sensitivity.
(D−d) is set to be about 10 to 100 μm. The smaller the (D−d), the higher the sensitivity.
Even if the inner diameter D of 2A is slightly changed, the A / E converter 1
8, the detected value changes greatly.

Further, as shown in FIG.
It is attached to the arm 36 via a support member 32 made of an elastic body (for example, a piano wire or the like). The arm 36 is slidably attached to a gantry 40 via sliders 38, 38, and a feed screw 44 connected to a rotation shaft of a motor 42 is screwed into the arm 36. Thus, when the motor 42 is driven, the feed screw 44 rotates, and the arm 36 moves up and down.

A linear scale 4 is provided above the arm 36.
6 are provided. The linear scale 46 is the arm 3
6 and outputs the detection signal to the control unit 20. The control unit 20 controls the motor 4 based on the detection signal.
2 to control the amount of movement of the arm 36, that is, the work 2
Adjust the vertical position of 2.

Next, the operation of the measuring apparatus 10 configured as described above will be described.

First, compressed air is supplied from the air source 12,
Compressed air is injected from the supply port 28A of the measurement table 28 to the hole 22A. Next, the motor 42 is driven to lower the arm 36 at a constant speed, and the measuring ball 30 is inserted into the hole 22A, and the inserted measuring ball 30 is lowered along the hole 30. Then, the back pressure when the compressed air passes through the gap between the measuring ball 30 and the inner wall of the hole 22A is detected at a plurality of locations (or continuously) at predetermined intervals. The back pressure is measured by a measuring ball 3
Since it depends on the size of the gap between 0 and the inner wall of the hole 22A,
By comparing the detected value of the back pressure with the master reference value in the control unit 20, it can be converted into the inner diameter of the hole 22A. Thus, the inner diameter of the hole 22A can be measured at a plurality of locations, and the shape of the hole 22A can be obtained. Here, the reference value of the master is a value obtained by measuring the master under the same conditions as the measurement prior to the measurement, and is performed each time the measurement conditions are changed.

At the time of measurement, the measuring ball 30 has a hole 22A.
An automatic centripetal action (or an automatic centering action) works by the compressed air passing through the gap between the inner wall of the lens and the measuring ball 30. Therefore, the support member 32 is elastically deformed, and the measurement sphere 30 is
It is automatically placed at the center of A. As a result, the compressed air passes through the gap formed substantially uniformly around the work 22. By detecting the back pressure at this time, the outer diameter of the work 22 can be accurately measured.

As described above, according to the measuring apparatus 10 of the present embodiment, the back pressure is measured at a plurality of points while moving the measuring ball 30 along the hole 22A.
A plurality of points can be obtained at predetermined intervals in the depth direction of A. Therefore, the shape of the hole 22A can be obtained, and the shape of the hole 22A having a non-uniform diameter can also be obtained. For example, when a taper is formed in the hole 22A, the angle of the taper can be obtained. Further, as shown in FIG. 7, even when the hole 22A has a reduced diameter portion or an increased diameter portion, the shape of the reduced diameter portion or the increased diameter portion can be obtained. Further, the measuring device 10 can also perform an inspection as to whether the diameter of the hole 22A is constant.

In the above-described embodiment, the arm 36
Is lowered at a constant speed, but need not be at a constant speed.
In this case, the position of the measuring sphere 30 is detected by the linear scale 46 at the same time when the back pressure is detected by the A / E converter 18. Thereby, the measurement of the inner diameter of the hole 22A and the recording of the measurement position can be performed simultaneously. Therefore, the shape of the hole 22A can be obtained.

Further, in the above-described embodiment, the back pressure of the compressed air is detected. However, the present invention is not limited to this, and the compressed air when the compressed air passes through the gap between the inner wall of the hole 22A and the measuring ball 30 is detected. The flow rate of air may be detected. In this case, similarly to the above-described embodiment, the control unit 20 can accurately measure the inner diameter of the hole 22A by comparing the detected value with the master reference value.

Further, the present invention is not limited to the detection of the back pressure and the flow rate of the compressed air.
It may be converted to the inner diameter of A.

FIG. 3 shows a measuring apparatus 50 according to the second embodiment.
FIG. 4 is a side view showing a coupling mechanism between the arm 36 and the support member 32. As shown in FIG. The measuring device 50 shown in these figures is a device for measuring the center line of the hole 22A.

In the measuring device 50, a disk 52 is attached to the upper end of the support member 32, and the disk 52 is connected to the arm 36 via four piezoelectric sensors 54, 54. As shown in FIG. 5, the support member 32 is connected to the center of the disk 52, and the piezoelectric sensors 54, 54... Are arranged at predetermined intervals around the disk 52. Each piezoelectric sensor 54 detects the drag received by the measuring ball 30 by dividing it in four directions, and outputs the detection signal to the control unit 20. When receiving the detection signal from each piezoelectric sensor 54, the control unit 20 calculates the rotational moment from the difference between the detected values. Then, the position of the measuring ball 30 is obtained from the rotational moment and the amount of elevation of the arm 36 detected by the linear scale 46.

The measuring device 50 configured as described above inserts the measuring sphere 30 into the hole 22A to which the compressed air is supplied, and moves the measuring sphere 30 in the depth direction of the hole 22A while changing the position of the measuring sphere 30. Detection is performed at a plurality of locations (or continuously) at predetermined intervals. As described above, the measurement sphere 30 at the time of measurement automatically moves to the center of the hole 22A by the automatic centripetal action. Therefore, when the measuring ball 30 is lowered along the hole 22A, the locus of the center of the measuring ball 30 is
A coincides with the center line of A. For example, as shown in FIG. 6, when the hole 22A is formed to be curved, the measuring sphere 30
It moves along the center line of the hole 22A indicated by the dashed line. Therefore, the rotation moment is calculated from the detection values of the piezoelectric sensors 38, 38, and the locus of the center position of the measuring ball 30 is obtained, whereby the center line of the hole 22A can be obtained. Thereby, the curvature and the like of the hole 22A can be measured. Similarly, when the hole 22A is bent, the bending angle can be obtained, and when the hole 22A is formed obliquely, the angle of the hole 22A can be obtained.

As described above, according to the measuring device 50, the piezoelectric sensor 5 is moved while moving the measuring ball 30 along the hole 22A.
By detecting a plurality of locations at 4, 54...
Can be measured at a plurality of locations, and the center line of the hole 22A can be obtained.

By the way, the measuring device 50 is a piezoelectric sensor 5
By adding the detected values of 4, 54.
You can calculate the total drag received by. Therefore, by comparing this calculated value with the reference value of the master, the inner diameter of the hole 22A can be obtained as in the first embodiment.
For example, as shown in FIG. 7, when the hole 22A has a reduced diameter portion or an increased diameter portion, the shape of the reduced diameter portion or the increased diameter portion can be determined by determining the inner diameter of the hole 22A at a plurality of locations.

Further, the measuring device 50 is provided for each piezoelectric sensor 5.
From the detection values of 4, 54...
A and the inner diameter of A are obtained at the same time. Therefore, even when the hole 22A has a complicated shape (that is, when the center line of the hole 22A is non-linear and not a constant diameter), the shape can be obtained. For example, as shown in FIG.
When the measuring ball 30 is moved in the depth direction of the hole 22A when the measuring ball 30 is formed, the measuring ball 30
It moves along the center line of 2A. By calculating the reaction force and rotational moment received by the measuring ball 30 from the detected values of the piezoelectric sensors 54, 54 at this time, the inner diameter and the center position of the hole 22A can be obtained. The shape of the hole 22A can be specifically acquired by obtaining the inner diameter and the center position of the hole 22A at a plurality of locations. Thus, the measuring device 50
Can determine the center position and the inner diameter of the hole 22A at a plurality of locations, so that various hole shapes can be obtained.

In the above-described embodiment, four piezoelectric sensors 54 are provided for obtaining the rotational moment. However, three or more piezoelectric sensors 54 may be used. Further, a load cell may be used instead of the piezoelectric sensor 54.

FIG. 9 shows a measuring device 62 according to the third embodiment.
FIG. 3 is a block diagram showing the structure of FIG.

The measuring device 62 shown in FIG.
Is mounted on an X-axis Y-axis stage 64 via three or more piezoelectric elements (not shown).
The axis stage 64 is attached to the arm 36. X axis Y
The axis stage 64 supports the disk 52 so as to be slidable in the horizontal direction, and detects the position of the disk 52 by a built-in sensor (not shown).

The measuring device 62 configured as described above adjusts the position of the disk 52 with the X-axis and Y-axis stages 64 until the detected values of the respective piezoelectric elements become equal. Thereby, the drag received by the measuring ball 30 matches the axial direction of the hole 22A. Therefore, by detecting the position of the disk 52 with a sensor built in the X-axis and Y-axis stages 64, the center position of the measuring sphere 30 is determined. Thereby, the center line of the hole 22A can be obtained.

In the third embodiment, the support member 32 may be formed of a rigid body, and the support member 32 may be directly connected to the X-axis Y-axis stage 64.
In this case, since the upper end position of the support member 32 changes according to the position of the measurement sphere 30, the position of the measurement sphere 30 can be detected by a sensor built in the X-axis Y-axis stage 64.

As shown in FIG. 10, the support member 32 may be attached to the arm 36 using a floating mechanism. The support member 32 shown in FIG. 10 is formed of a rigid body, and is attached to a disk 52 at the upper end of the support member 32. The disk 52 is slidably supported in a horizontal direction by a hydrostatic bearing 58. As shown in FIG. 11, the hydrostatic fluid bearing 58 includes position detection sensors 60, 60 such as an optical encoder and a magnetic scale, and the position detection sensor 60 controls the position of the disk 52, that is, the position of the measurement ball 30. Detect the position on the horizontal plane. The position of the measuring sphere 30 is calculated based on the position on the horizontal plane of the measuring sphere 30 detected by the position detection sensor 60 and the vertical position of the measuring sphere 30 detected by the linear scale 46. Thus, when the measuring ball 30 is passed through the hole 22A, the locus of the center position of the measuring ball 30 can be obtained, and the center line of the hole 22A can be obtained.

In the first, second and third embodiments, the measuring ball 30 is moved against the flow of the compressed air. However, the present invention is not limited to this. The measurement may be performed while moving the ball 30.

The fluid supplied to the hole 22A is not limited to compressed air, but a gas or liquid other than air may be supplied to the hole 22A.

Further, a temperature control means for controlling the temperature of the fluid supplied to the hole 22A may be provided.

[0041]

As described above, according to the method and the apparatus for measuring the shape of a hole according to the present invention, the float is moved along the depth direction of the hole to which the fluid is supplied, and the position of the float and the inner diameter of the hole are determined. Are detected at a plurality of locations, so that various hole shapes can be measured.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a structure of a first embodiment of a hole shape measuring device according to the present invention.

FIG. 2 is a side sectional view showing a characteristic portion of the hole shape measuring device shown in FIG. 1;

FIG. 3 is a block diagram showing a structure of a hole shape measuring apparatus according to a second embodiment of the present invention;

FIG. 4 is a side view showing a characteristic portion of the hole shape measuring device shown in FIG. 3;

FIG. 5 is a sectional view taken along lines 5-5 in FIG. 4;

FIG. 6 is an explanatory view showing the operation of the hole shape measuring device shown in FIG. 3;

FIG. 7 is an explanatory view showing the operation of the hole shape measuring device shown in FIG. 3;

FIG. 8 is an explanatory view showing the operation of the hole shape measuring device shown in FIG. 3;

FIG. 9 is a block diagram showing the structure of a third embodiment of the hole shape measuring device according to the present invention.

FIG. 10 is a side view showing a supporting structure of the measuring sphere different from FIG. 9;

11 is a sectional view taken along the line 11-11 in FIG. 10;

[Explanation of symbols]

10: measuring device, 12: air source, 16: regulator,
18 ... A / E converter, 20 ... Control unit, 22 ... Work, 2
2A: hole, 28: measuring table, 28A: supply port, 30: measuring ball, 32: support member, 36: arm, 46: linear scale, 54: piezoelectric sensor

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Kazuo Nakajima 9-7-1, Shimorenjaku, Mitaka-shi, Tokyo F-term (reference) 2F066 AA23 AA31 DD11 FF09 HH18 JJ11 JJ12 MM03

Claims (8)

[Claims] 1. A hole shape measuring method for measuring the inner diameter of a hole at a plurality of positions along a depth direction of the hole to obtain the shape of the hole, comprising: inserting a float into a hole to which fluid is supplied; While moving along the depth direction of the hole, the back pressure when the fluid passes through the gap between the inner wall of the hole and the float, the flow rate, or the drag received by the float is detected at a plurality of locations, and the detected value is detected. A method for measuring the shape of a hole, wherein the value is converted into an inner diameter of the hole by comparing with a reference value. 2. A hole shape measuring device for measuring an inner diameter of a hole at a plurality of positions along a depth direction of the hole to obtain a shape of the hole, wherein: a fluid supply unit for supplying a fluid to the hole; A float inserted into the hole, a moving means for moving the float along the depth direction of the hole, and a back pressure, a flow rate, or the float when the fluid passes through a gap between the inner wall of the hole and the float. A hole shape measuring device, comprising: detecting means for detecting a plurality of received drags; and converting means for comparing a detection value detected by the detecting means with a reference value and converting the detected value into an inner diameter of the hole. . 3. A hole shape measuring method for obtaining a hole shape by measuring a center line of the hole, comprising inserting a float into a hole to which fluid is supplied, and moving the float along a depth direction of the hole. A method for measuring the shape of a hole, comprising detecting a plurality of positions of the float while moving the hole, obtaining a center line of the hole from the detected values, and acquiring a shape of the hole based on the center line. 4. A hole shape measuring device for measuring a center line of a hole to obtain a hole shape, comprising: a fluid supply unit for supplying a fluid to the hole; a float inserted into the hole; A hole shape measuring device comprising: moving means for moving a float along a depth direction of the hole; and position detecting means for detecting a plurality of positions of the float. 5. A method for measuring the shape of a hole, comprising measuring an inner diameter of the hole at a plurality of positions along a depth direction of the hole, and measuring a center line of the hole to obtain a shape of the hole. A back pressure, a flow rate, or a drag received by the float when the fluid passes through the gap between the inner wall of the hole and the float while inserting the float into the hole and moving the float along the depth direction of the hole. And, the position of the float is detected at a plurality of locations, and the back pressure, the flow rate, or the detected value of the drag received by the float is compared with a reference value and converted into the inner diameter of the hole, and the detected value of the position of the float is detected. Obtaining a center line of the hole from the following formula, and acquiring a shape of the hole based on the center line of the hole and the inner diameter of the hole. 6. A hole shape measuring apparatus for measuring an inner diameter of a hole at a plurality of positions along a depth direction of the hole, and measuring a center line of the hole to obtain a shape of the hole. A fluid supply unit for supplying a fluid; a float inserted into the hole; a moving unit for moving the float along a depth direction of the hole; when the fluid passes through a gap between an inner wall of the hole and the float. Detection means for detecting the back pressure, flow rate, or drag received by the float at a plurality of locations; conversion means for comparing the detection value detected by the detection means with a reference value to convert the value into the inner diameter of the hole; A hole shape measuring device, comprising: position detecting means for detecting a plurality of positions. 7. The hole shape measuring apparatus according to claim 4, wherein said position detecting means detects the drag received by said float in three or more directions. 8. The hole shape measuring device according to claim 2, wherein the float is supported by an elastic body.