JP3390971B2 - Method and apparatus for measuring the inner diameter of a hole - Google Patents

Description

Detailed Description of the Invention

[0001]

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

[0002]

2. Description of the Related Art An air micrometer is one of the measuring devices for measuring the inner diameter of a hole formed in a work. The conventional air micrometer, as shown in FIGS. 26 and 27, inserts the measuring head 1 into the hole 3 of the work 2, injects compressed air from the nozzles 4 and 4 of the measuring head 1, and
To detect the back pressure of. The back pressure of the nozzle 4 is the nozzle 4 and the hole 3
Since it depends on the distance from the inner wall of the hole, the detected value can be converted into the size of the inner diameter of the hole 3 by comparing with the reference value of the master obtained in advance. Such an air micrometer has an advantage that the inner diameter of the hole 3 can be measured with high accuracy without contacting the work 2.

[0003]

However, the conventional air micrometer measures the position deviated from the inner diameter of the hole 3 when the center of the measuring head 1 deviates from the center of the hole 3, as shown in FIG. Therefore, there is a drawback that an eccentricity error occurs and the measurement accuracy is lowered. In addition, as shown in FIG. 27, the conventional air micrometer measures the radius of the hole 3 obliquely when the measuring head 1 is inserted into the hole 3 at an angle, and an angular error occurs, which causes measurement. There was a drawback that the accuracy was lowered.

Further, in the conventional air micrometer, in order to improve the measurement accuracy, the plurality of nozzles 4 and 4 must be machined with a small diameter and evenly with high accuracy, and the processing cost of the measuring head 1 is high. There was also a drawback. Further, in order to improve the measurement accuracy, it is necessary to reduce the guide clearance (gap between the work and the measurement head), and there is a drawback that the measurement head 1 comes into contact with the work 2 when the measurement head 1 is inserted and the work 2 is damaged. there were.

The present invention has been made in view of the above circumstances, and it is possible to accurately measure a hole in a work without damaging the work, and a method for measuring the inner diameter of the hole at low cost is provided. The purpose is to provide a device.

[0006]

In order to achieve the above-mentioned object, the present invention provides a method for measuring the inner diameter of a hole formed in a workpiece, in which a fluid is supplied to the hole in which a float is inserted, The back pressure of the fluid when the supplied fluid passes through the gap between the inner wall of the hole and the float, the flow rate, the drag force received by the float, or the displacement of the float is detected, and the detected value is compared with a reference value. It is characterized in that it is converted into the inner diameter of the hole.

Further, in order to achieve the above object, the present invention is a hole inner diameter measuring device for measuring an inner diameter of a hole formed in a work, wherein a float inserted into the hole and a hole into which the float is inserted. Fluid supply means for supplying a fluid to the, and the back pressure, the flow rate of the fluid when the fluid supplied by the fluid supply means passes through the gap between the hole inner wall and the float, or the drag force received by the float, or the float Detection means for detecting the amount of displacement,
A conversion unit that compares the detection value detected by the detection unit with a reference value and converts the detection value into the inner diameter of the hole.

According to the present invention, the float is inserted into the hole formed in the work to supply the fluid, and when the supplied fluid passes through the gap between the inner wall of the hole and the float, the float tries to be positioned at the center of the hole. (Automatic centripetal action), whereby it is automatically placed at the center of the hole. Therefore, the eccentricity error and the angle error unlike the conventional device do not occur, and the inner diameter of the hole can always be measured with high accuracy. Further, since it is not necessary to accurately align the center of the supply port of the fluid supply means with the center of the hole, the measurement can be easily performed in a short time.

Further, according to the present invention, since the inner diameter of the hole can be measured without contacting the work, like the air micrometer, it is possible to prevent the work from being scratched.

Further, according to the present invention, it is possible to perform measurement at low cost without requiring a nozzle or a measuring head which requires highly accurate processing unlike the conventional apparatus.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of a hole inner diameter measuring method and apparatus according to the present invention will be described below with reference to the accompanying drawings.

FIG. 1 shows a measuring apparatus 10 according to the first embodiment.
3 is a block diagram showing the configuration of FIG.

As shown in FIG. 1, the compressed air supplied from the air source 12 is dust-removed by the filter 14 and adjusted to a constant pressure by the regulator 16, and then the A / E converter 18 is used.
The air is supplied to the air supply passage 28B in the measuring stand 28 through the throttle installed in the (air / electric converter) and the connector 33.

A supply port 28A communicating with the air supply passage 28B is formed on the upper surface of the measuring table 28, and the work 2
2 is placed. A cylindrical hole 22A is formed in the work 22, and the measuring sphere 30 is inserted into this hole 22A.

The compressed air supplied to the air supply path 28B of the measuring table 28 is jetted from the supply port 28A to the hole 22A,
It is blown out through the gap between the inner wall of the hole 22A and the measuring sphere 30. The A / E converter 18 changes the pressure at this time to
It is converted into an electric signal by the built-in bellows and the differential transformer and output to the control unit 20. When the diameters of the holes 22A are different, the pressure slightly changes, and the control unit 20 calculates the inner diameter of the work 22 based on the changed electric signal, and the calculated data is displayed on the monitor of the control unit 20, for example, as described later. To display.

FIG. 2 is a sectional view showing the structure of the characteristic portion of the measuring apparatus 10 shown in FIG. As shown in the figure, an air leakage prevention seal (O ring) is provided around the supply port 28A.
34 is provided, and the air leakage prevention seal 34 prevents air from leaking from the gap between the measuring table 28 and the work 22.

The measuring sphere 30 is formed into a spherical shape with high processing accuracy, and the material thereof is, for example, ceramic, resin, steel, light alloy or the like. The diameter d of the measuring sphere 30 is the hole 22A.
Is formed to be slightly smaller than the diameter D. The closer the diameter d of the measuring sphere 30 is to the value of the diameter D of the hole 22A, the higher the sensitivity becomes, and the back pressure changes greatly even if the gap between the hole 22A and the measuring sphere 30 is slightly changed. However, if the diameter d of the measuring sphere 30 is too close to the diameter D of the hole 22A, it becomes difficult to insert the measuring sphere 30 into the hole 22A. Therefore,
Depending on the hole diameter D to be measured and the required sensitivity, the gap (D-d) between the measuring sphere 30 and the work 22 is, for example, 10 to 100.
Set around μm as a guide. This allows the measuring sphere 3
0 can be smoothly inserted into the hole 22A, and the dimension of the hole 22A can be measured accurately. The measuring sphere 30
If the diameter d of is larger than the supply port 28A, the measuring sphere 30 is prevented from falling into the supply port 28A.

The supporting member 32 is formed in a cylindrical shape and has a diameter smaller than that of the measuring sphere 30. This support member 32
Is supported by the column 38 via the arm 36 of FIG. 1, and is supported in the same direction as the hole 22A, for example, in the vertical direction. The lower end surface of the support member 32 is formed perpendicularly to the axis of the hole 22A, and the lower end surface is processed to be smooth.

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

First, as shown in FIG.
The work 22 is placed on the upper surface of 8. At this time, work 2
The two holes 22A are arranged on the supply port 28A. Then, the measuring sphere 30 is inserted into the hole 22A of the work 22. At this time, since the measuring sphere 30 is formed into a spherical shape, even if the measuring sphere 30 contacts the inner wall of the hole 22A, the inner wall is not damaged.

Next, as shown in FIG. 3B, after inserting the support member 32 into the hole 22A, the air source 12 shown in FIG.
From the supply port 28A. At this time, the injected compressed air is injected into the hole 22A without leaking from the gap between the work 22 and the measuring table 28.

Since the compressed air is jetted from the supply port 28A, the measuring sphere 30 receives the jetted compressed air and floats, as shown in FIG. 3 (c). When floating, the measuring sphere 30 is formed into a spherical shape, so
Even if it contacts the inner wall of 2A, the inner wall is not damaged. The floating measurement sphere 30 contacts the lower end surface of the support member 32 and is maintained in a floating state. The compressed air is a measuring sphere 30.
Through the gap between the inner wall of the hole 22A and the inner wall of the hole 22A, and blows out from the upper opening. The back pressure at this time is the measurement ball 30 and the hole 22.
The back pressure depends on the size of the gap between the inner wall of A and A
The inner diameter of the hole 22A can be obtained by detecting with the E converter 18 and comparing this detected value with the reference value of the master in the control unit 20 to convert it into the inner diameter of the hole 22A. In addition,
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 condition is changed.

At the time of measurement, the measuring sphere 30 includes the measuring sphere 3
The compressed air passing through the gap between 0 and the inner wall of the hole 22A causes an automatic centripetal action (or self-centering action) to automatically move the measuring sphere 30 to the center of the hole 22A. That is, FIG.
As shown by the chain double-dashed line in FIG. 2, when the measurement sphere 30 that is in contact with the support member 32 is displaced from the center of the hole 22A, the spherical measurement sphere 30 rolls on the smooth lower end surface of the support member 32, and FIG. Move to the center as shown by the solid line. Therefore, the compressed air passes through the gap formed approximately evenly around the measurement sphere 30, and the inner diameter of the hole 22A can be accurately obtained by detecting the back pressure at this time.

As described above, according to the measuring apparatus 10 of the present embodiment, the inner diameter of the hole 22A can be measured without accurately centering the center of the supply port 28A and the center of the hole 22A. As a result, eccentricity error and angle error do not occur, and the inner diameter of the hole 22A can always be measured accurately. In particular, in the measuring device 10, since the measuring sphere 30 is automatically positioned at the center of the hole 22A by the automatic centripetal action, the inner diameter of the hole 22A can be accurately measured.

Further, since the measuring device 10 only inserts the measuring sphere 30 into the hole 22A and injects compressed air, it is easy to operate and can perform accurate measurement in a short time.

Further, since the measuring device 10 can measure the work 22 without contacting it, like the conventional air micrometer, the work 22 can be measured without being scratched.

Further, according to the measuring apparatus 10, even when measuring a small diameter hole, it is sufficient to prepare the small measuring ball 30 according to the small hole, and the preparation of only the measuring ball 30 is necessary. It is possible to reduce the cost of the entire device. That is, according to the measuring device 10, the conventional air micrometer has a small diameter hole, for example, a diameter of 2 m, which is difficult to measure accurately at low cost due to the processing of the nozzle and the measuring head.
Even if the hole has a diameter of m or less, the inner diameter of the hole can be accurately measured at low cost by using the measuring sphere 30 having a small diameter.

In the above-described embodiment, the measuring sphere 30 is used.
Although the compressed air was jetted from the supply port 28A after being inserted into the hole 22A, the measuring sphere 30 may be inserted while jetting the compressed air.

In the above-described embodiment, the back pressure is detected by the A / E converter 18, but the present invention is not limited to this. Compressed air passes through the gap between the inner wall of the hole 22A and the measuring sphere 30. You may detect the flow rate of the compressed air at the time of performing. Also in this case, as in the case of the measuring device 10 described above, the control unit 20 compares the detected value with the reference value of the master, so that the hole 2
The inner diameter of 2A can be accurately obtained.

Furthermore, the present invention is not limited to the detection of the back pressure or flow rate of compressed air, but as shown below,
You may detect the reaction force which the measurement sphere 30 receives, and the amount of displacement of the measurement sphere 30 when the compressed air passes through the gap between the inner wall of the hole 22A and the measurement sphere 30.

FIG. 4 is a block diagram showing the structure of the measuring apparatus 40 of the second embodiment, and the same or similar members as those of the measuring apparatus 10 of the first embodiment shown in FIG. 1 are the same. The reference numerals are given and the description thereof is omitted.

A measuring device 40 shown in the figure is a device for detecting a reaction force received by the measuring sphere 30, and a supporting member 32 is attached to an arm 36 via a piezoelectric pickup 42. When the compressed air passes through the gap between the inner wall of the hole 22A and the measuring sphere 30, the piezoelectric pickup 42 measures the measuring sphere 30.
Detects the drag force received from the compressed air and outputs the detection signal to the control unit 20. When the control unit 20 receives the detection signal from the piezoelectric pickup 42, the detection value is converted into the inner diameter of the hole 22A by comparing it with the reference value of the master, as described above.

In the measuring device 40, the piezoelectric pickup 42 has been described as a means for detecting the reaction force received by the measuring sphere 30, but the measuring device 40 is not limited to this. For example, a strain gauge or the like can be used for detection. You may.

In the measuring device 46 shown in FIG. 5, a strain gauge 48 is attached to the arm 36 instead of the piezoelectric pickup 42, and the strain gauge 48 detects the strain of the arm 36. The control unit 20 receives a detection signal from the strain gauge 48 when the compressed air passes through the gap between the inner wall of the hole 22A and the measurement sphere 30, and obtains the displacement amount of the measurement sphere 30 from the strain characteristic of the arm 36, Further, this value is compared with the reference value of the master and converted into the inner diameter of the hole 22A.

The above-described measuring devices 10, 40, 46
In the above, the floating measurement sphere 30 is received and supported by the support member 32, but the present invention is not limited to this, and as shown below, it may be supported by attraction by magnetic force or may be supported via an elastic body.

In the measuring device shown in FIG. 6, a permanent magnet 52 is attached to the lower end of the support member 32.
A measuring sphere 30 made of metal such as steel is adsorbed and supported on. Further, the lower end surface of the permanent magnet 52 is formed on a surface substantially perpendicular to the axis of the hole 22A, and is mirror-finished and smoothed. As a result, when compressed air is supplied from the supply port 28A, the measuring sphere 30 rolls on the lower end surface of the permanent magnet 52 by the centering action of the permanent magnet 52 in spite of the attraction force of the permanent magnet 52, and is arranged at the center.

According to such a measuring device, the measuring sphere 30
Is attracted to the permanent magnet 52 by the magnetic force, it is not necessary to levitate the measuring sphere 30, and the inner diameter of the hole 22A can be measured quickly. In addition, the measuring sphere 30 is the permanent magnet 5
Since it is adsorbed to the supporting member 32 through the hole 22,
The measurement ball 30 and the support member 32 can be simultaneously put in and taken out of the hole 22A at the time of starting or ending the measurement of A, and the work can be easily performed. Further, since the measuring sphere 30 is attracted to the permanent magnet 52, it is possible to prevent the measuring sphere 30 from being lost, and it is possible to easily replace the measuring sphere 30.

In the measuring device described above, the permanent magnet 5
Although the measuring sphere 30 is attracted by 2 as shown in FIG. 7, it may be attracted by the electromagnet 54 as shown in FIG. Electromagnet 54
Is configured by providing the support member 32 as a ferromagnetic core (magnetic core) and providing the coil 56 on the support member 32. Also in this case, similarly to the case where the permanent magnet 52 is used, the operation of moving the measurement sphere 30 and the support member 32 into and out of the hole 22A and the operation of measuring the inner diameter of the hole 22A can be performed quickly. In the method using the electromagnet 54, the supply port 28
By stopping the current to the coil 56 when the compressed air is jetted from A, the magnetic force acting on the measuring sphere 30 disappears,
The measuring sphere 30 moves more smoothly to the center of the hole 22A.

In the measuring apparatus shown in FIG. 8, the measuring sphere 30 is elastically deformable in the horizontal direction, such as an elastic body 60 such as rubber or spring.
It is connected to the support member 32 via. In this measuring device, when compressed air is jetted from the supply port 28A, the measuring sphere 30 is subjected to an automatic centripetal effect, the elastic body 60 is deformed, and the measuring sphere 30 moves to the center of the hole 22A. That is, the elastic body 6
By interposing 0 between the measurement sphere 30 and the support member 32, the effect of the automatic centripetal action of the measurement sphere 30 can be obtained while the measurement sphere 30 and the support member 32 are completely connected. Therefore, according to this measuring device, the measuring sphere 3
Since 0 and the support member 32 are completely connected, the operation of moving the measurement sphere 30 and the support member 32 into and out of the hole 22A and the operation of measuring the inner diameter of the hole 22A can be performed more quickly, and the measurement sphere 30 The inner centroid of the hole 22A can be accurately measured by the automatic centripetal action.

Instead of connecting the measuring sphere 30 and the support member 32 with the elastic body 60, as shown in FIG. 9, the support member 32 may be provided with a floating mechanism using an air bearing or the like. That is, the support member 32 made of a rigid body and the arm 36 are connected to each other via the moving piece 62 supported so as to slide on the horizontal plane. Accordingly, when the measuring sphere 30 is subjected to the automatic centripetal action, the moving piece 62 moves on the horizontal plane, the measuring sphere 30 is arranged at the center of the hole 22A, and the inner diameter of the hole 22A can be accurately obtained. A floating mechanism may be provided on the support member 32 while the elastic body 60 is provided between the support member 32 and the measurement sphere 32.

FIG. 10 is a block diagram showing the structure of the measuring device of the third embodiment for measuring the closed hole 22B of the work, and FIG. 11 is a characteristic portion of the measuring device shown in FIG. It is a cross-sectional view showing the structure of.

The measuring device 64 of the third embodiment is constructed so that a supply port 66A (see FIG. 11) is formed in the measuring sphere 66 and compressed air is jetted from this supply port 66A. That is, as shown in FIG. 11, a columnar protrusion 68A is formed at the center of the lower end surface of the support member 68, and the lower end surface of this protrusion 68A is processed to be smooth. The support member 68 and the measuring sphere 66 are connected via a cylindrical elastic body 70 that is deformable in the horizontal direction, and the measuring sphere 66 is urged upward by the elastic body 70 to contact the lower end surface of the protruding portion 68A. It is touched.

The support member 68 is formed in a hollow shape, and a compressed air flow path 68B is formed therein. The flow path 68B is connected to the A / E via the connector 72 shown in FIG.
It is connected to the converter 18 and is supplied with compressed air from the air source 12. Further, the flow path 68B is branched at the lower end portion of the support member 68 and communicates with a plurality of openings 68C formed in the lower end surface. The plurality of openings 68C are formed to have the same diameter and are evenly arranged around the axis of the support member 68. As a result, the compressed air supplied from the A / E converter 18 passes through the flow path 68B in the support member 68 and is evenly blown out from the plurality of openings 68C. Multiple openings 6
The compressed air blown out from 8C passes through the air supply passage 66B of the measuring sphere 66 and does not leak to the outside.
A cylindrical space 74 surrounded by the elastic body 70 and the measuring sphere 66.
Is supplied to.

The compressed air supplied to the cylindrical space 74 is supplied through the air supply passage 66B in the measuring sphere 66 to the supply port 66A.
Is jetted from. The air supply passage 66B is provided with the support member 68.
Are evenly formed around the axis of.

In the measuring device 64 constructed as described above,
The compressed air injected from the supply port 66A is closed by the closing hole 22B.
Since the lower end of is closed, the measuring ball 66 and the closing hole 22
It flows upward through the gap with the inner wall of B. At this time,
An automatic centripetal action works on the measuring sphere 66, and the spherical measuring sphere 66
Smoothly rolls on the plane of the support member 68, and the measurement sphere 66 is supported by the support member 68 via the elastic body 70, so that the measurement sphere 66 surely moves to the center. Therefore, by measuring the back pressure (or the flow rate of compressed air) with the A / E converter 18, the inner diameter of the closed hole 22B can be accurately measured.

As described above, the measuring device 6 of the third embodiment
According to 4, since the supply port 66A is formed in the measuring sphere 66, the inner diameter of the closing hole 22B can be accurately measured even with the closing hole 22B.

Further, according to the measuring device 64, the measuring sphere 66
Is connected to the support member 68, the measurement ball 66 and the support member 68 can be easily moved in and out of the closing hole 22B, and the measurement ball 66 can be prevented from being lost.

Furthermore, according to the measuring device 64, the measuring sphere 6
Since the supply port 66A is formed at 6, the inner diameter of the closing hole 22B can be measured by merely inserting the measuring ball 66 and the supporting member 68 into the closing hole 22B. Therefore, the measurement can be performed without being influenced by the direction of the closed hole 22B and the size of the work 22.

In FIG. 10, in the A / E converter 18,
An example of detecting the back pressure or the flow rate of the compressed air has been shown.
To detect the drag force that the measuring sphere 66 receives,
The displacement of the measuring sphere 66 may be detected as shown in FIG.

Further, the measuring device 64 is not limited to the measurement of the inner diameter of the closed hole 22B, and even if the hole is opened in multiple directions, all the openings except one direction are sealed with sealing members such as stoppers. The inner diameter of the remaining unidirectional hole can be measured by sealing with.

Further, in the measuring device 64, the arm 36 is not connected to the support column 38, and the operator does not connect the arm 36 (or the support member 3).
2) may be held in the hand for measurement.

Further, the measuring device 64 may have a structure in which the measuring sphere 66 is supported by the elastic member 70 via the supporting member 68, and the compressed air can be jetted to the tip side of the measuring sphere 66. For example, in the measuring device shown in FIG. 24, a spherical measuring sphere 75 is fixed in a state of being penetrated by a cylindrical supporting member 76, and this supporting member 76 is connected to a pipe 78 via a cylindrical elastic body 77. ing. The pipe 78 is shown in FIG.
Compressed air from the air source 12 shown in FIG. 0 is supplied and jetted to the inner side of the measuring sphere 75 via the support member 76. The jetted compressed air blows upward from the gap between the measuring sphere 75 and the hole 22B, and gives an automatic centripetal effect to the measuring sphere 75.
The measuring sphere 75 swings around the elastic body 77 and is arranged at the center of the hole 22B. Thereby, the inner diameter of the hole 22B can be measured with high accuracy. Instead of connecting the support member 76 to the pipe 78 via the elastic body 77, the support member 76 may be provided with a floating mechanism.

The measuring device 64 of the third embodiment
Is a device for measuring the closed hole 22B, but it is also possible to measure the penetrated hole 22A by providing a plurality of measuring balls. An example is shown below.

The measuring apparatus shown in FIG. 12 includes a measuring sphere 80 having a supply port 80A formed therein and a measuring sphere 82 having no supply port. The measuring sphere 80 includes an elastic body 70 on the support member 68.
And is brought into contact with the projecting portion 68A of the supporting member 68. A measuring sphere 82 is connected to the lower end of the measuring sphere 80 via an elastic body 84 such as rubber that is elastically deformable in the horizontal direction. The measuring sphere 80 and the measuring sphere 82 are formed with the same outer diameter, and are formed with a diameter slightly smaller than the diameter D of the hole 22A.

The measuring sphere 80 has a plurality of supply ports 80.
A, 80A ... Are formed. A plurality of supply ports 80A,
80A ... Are respectively formed in the radial direction and communicate with the cylindrical space 74. Also, a plurality of supply ports 80A, 8
0A ... Are formed with the same diameter, and the support member 68
Are evenly arranged with respect to the axis. As a result, the compressed air supplied to the cylindrical space 74 is supplied to the plurality of supply ports 8
It is blown out evenly from 0A, 80A.

In the measuring device constructed as described above, compressed air is blown out between the measuring sphere 80 and the measuring sphere 82. Therefore, the compressed air blown out is measured by the measurement ball 80 and the hole 2.
While flowing out upward from the gap with 2A, the measurement ball 82
And flows out downward from the gap between the hole 22A and the hole 22A. The measuring sphere 80 is supported by the supporting member 68 via the elastic body 70, and further,
Since the measuring sphere 82 is supported by the measuring sphere 80 via the elastic body 84, the measuring spheres 80 and 82 are arranged at the center of the hole 22A by the automatic centripetal action. Since the back pressure at this time depends on the size of the gap between the measurement sphere 80 and the hole 22A and the size of the gap between the measurement sphere 82 and the hole 22A, the back pressure is measured by the A / E converter 18. By detecting and comparing with the reference value of the master, the inner diameter of the hole 22A can be accurately measured.

As described above, according to the above-described measuring apparatus, since the plurality of measuring balls 80 and 82 are provided and the compressed air is jetted between the measuring balls 80 and 82, the compressing air is compressed from the direction opposite to the supporting member 68. No need to inject air. That is, the hole 22
The measurement can be performed only by inserting the measurement balls 80, 82 and the support member 68 from one side of A. Therefore,
This measuring device is suitable for measuring the holes 22A formed in a large work.

Further, this measuring device is constructed so that the flow of compressed air becomes uniform around the axis of the support member 68. Therefore, the measurement sphere 66 is compressed by compressed air.
The inner diameter of the hole 22B can be accurately measured without tilting.

It should be noted that the above-mentioned measuring device has two measuring balls 80.
It suffices that the compressed air is jetted between the measurement ball 82 and the measurement sphere 82. For example, a supply port is formed in the elastic body 84,
As shown in FIG. 5, the supply port may be formed in the member connecting the two measurement balls. The measuring device shown in FIG. 25 is fixed in a state where a spherical measuring sphere 85 is penetrated by a cylindrical supporting member 87. The support member 87 has a cylindrical elastic body 8 on the base end side.
8 is connected to the pipe 89, and the tip side is sealed by a plug 83 made of an elastic body. A measuring ball 86 is adhered to and supported by the lower end of the stopper 83. Further, on the outer peripheral surface of the lower end portion of the support member 87, supply ports 87A, 87A ...
Are evenly formed. Therefore, when compressed air is supplied to the pipe 89, the supply port 87 is supplied via the support member 87.
A, 87A ... Are injected between the measuring sphere 85 and the measuring sphere 86, and the injected compressed air flows out between the measuring sphere 85 and the hole 22A and between the measuring sphere 86 and the hole. Measuring ball 85
Is supported by the elastic body 88, it is arranged at the center of the hole 22A by the automatic centripetal action, and the measuring sphere 86 is connected to the measuring sphere 85 through the elastic body stopper 83. , Is arranged at the center of the hole 22A by an automatic centripetal action. Thereby, the inner diameter of the hole 22A can be accurately measured. Instead of connecting the support member 87 via the elastic body 88, the support member 87 may be provided with a floating mechanism.

In the first, second and third embodiments described above, air is injected into the hole 22A (or 2B) of the work 22 to measure the inner diameter of the hole 22A. Of course, gas or liquid other than air may be used. Further, temperature control means for controlling the temperature of the fluid may be provided.

Further, in the first, second and third embodiments described above, spherical measuring balls 30, 66, 80 and 82 are used as floats.
Was used, but is not limited thereto. For example,
The float as shown in FIGS. 13 to 23 or any other shape other than this may be used as long as the hole can be narrowed with respect to the axis of the hole.

The float 90 shown in FIG. 13 has a shape formed by cutting a spherical body in a circumferential shape, and the diameter d1 of the cut portion is formed slightly smaller than the diameter D of the hole 22A. Since the float 90 can be easily processed by cutting a sphere, the hole 2 to be measured
This is effective when it is difficult to obtain a sphere having a diameter suitable for 2A.

The float 92 shown in FIG. 14 is formed in a capsule type having a columnar portion 92A and hemispherical portions 92B and 92B. In the float 92, the attitude of the float 92 is stabilized by lengthening the central portion 92A, and a stable measurement result with a small measurement error can be obtained.

The float 94 shown in FIG. 15 is formed in an elliptical shape, that is, a shape obtained by rotating the elliptical shape by 180 ° about the major axis (or the minor axis). Further, the float 96 shown in FIG. 16 is formed in a diameter difference roller type (or barrel type). Float 9 formed in this way
Nos. 4 and 96 can be easily inserted into the hole 22A, and stable measurement results can be obtained.

The float 98 shown in FIG. 17 is formed in a conical shape. By inserting the float 98 into the hole 22A so that the apex side 98A faces the fluid outlet side, the air resistance of the float 98 can be reduced. Therefore, the pressure of the supplied fluid can be reduced.

The float 100 shown in FIG. 18 is a cone up-and-down type, and is formed in a shape in which the bottom surfaces of two cones are pasted together. Since the vortex is not generated behind the float 100 in the float 100 thus formed, the air resistance can be further reduced.

The float 102 shown in FIG. 19 is formed in a streamlined shape. Therefore, the air resistance of the float 102 can be minimized.

The float 104 shown in FIG. 20 is of a low center of gravity type, that is, the center of gravity of the entire float 104 is arranged downward, and the floating posture is stabilized.

The float 106 shown in FIG. 21 is of a type with an insertion guide, and is provided with a guide portion 106A having a small diameter in its lower portion, so that it can be easily inserted into the hole 22A. Further, the float 106 has a hemispherical lower end of the guide portion 106A, and is configured so as to easily obtain an automatic centripetal action.

22A and 22B are a plan sectional view and a side sectional view of the spline type float 108. The float 108 is a spline type, that is, a gear-shaped columnar portion 108A, and a centripetal action portion 1 formed in a hemispherical shape.
08B and. The float 108 is replaced by the columnar portion 1.
When inserted into the spline-shaped hole 22D having a similar shape to 08A, the float 108 is automatically centered by the centripetal action portion 108B and is arranged at the center of the hole 22D. Is formed. Therefore, the dimension of the hole 22D can be measured by comparing with the reference value of the spline-shaped master. The centripetal action portion 108B is not limited to the hemispherical shape, and may have a conical shape.

The float 110 shown in FIG. 23 is formed in a diamond shape, that is, a shape in which two quadrangular pyramids are combined on the bottom surface. The float 110 is suitable for measuring the square hole 22C.

The shape of the float is preferably such that the automatic centripetal effect works effectively when the fluid is supplied to the hole. For example, the side to which the fluid is supplied is formed in a hemispherical shape or a conical shape. . Alternatively, a combination of these float shapes may be used.

Further, it is preferable that the cross-sectional shape of the float in the direction orthogonal to the axis of the hole is similar to the shape of the hole. For example, if a polygonal hole is formed,
A polygonal pyramid of that shape or a shape obtained by combining the polygonal pyramids on the bottom surface is preferable. As a result, gaps are evenly formed around the float, and the hole dimensions can be measured accurately. Therefore, according to the present invention, by changing the cross-sectional shape of the float, it is possible to accurately measure the size of the hole having any cross-sectional shape.

Further, in the above-described embodiment, the measuring sphere 3
By suppressing 0 from above by the support member 32,
Although the measurement sphere 30 is prevented from coming out of the hole 22A, the present invention is not limited to this, and the measurement sphere 30 may be supported from below by a string-shaped member or the like. Alternatively, the tension or elongation of the string-shaped member may be measured.

Further, in the measuring apparatus 10 shown in FIG. 1, the measurement may be performed while the measuring sphere 30 is in a state of floating in the hollow. That is, by the buoyancy force that the measurement sphere 30 receives by ejecting the fluid and the own weight of the measurement sphere 30 are balanced,
The back pressure and the flow rate are detected in a state in which the measurement sphere 30 is not in contact with the support member 32 and is kept hollow. In this case, by comparing with the reference value of the master under the same conditions, the hole 22
The dimensions A to 22D can be accurately obtained.

Further, in the above-described first embodiment, it is preferable that the work 22 is installed on the measuring table 28 so that the center of the hole 22A and the center of the supply port 28A are aligned as closely as possible. Therefore, the work 22 is attached to the measuring table 28.
Positioning means may be provided on the measuring table 28 for easy positioning.

The measuring table 28 has a hole 22 in the work 22.
When the size of A is changed, the supply port 28A may be replaced with a different one.

Further, in the above-described embodiment, the measurement is performed by injecting the fluid from below into the hole 22A formed in the vertical direction, but the fluid is injected into the hole 22A from above and the support member 32 is used from below. You may measure by supporting.
Further, not only the hole 22A formed in the vertical direction but also the hole formed in an oblique direction or horizontally may be measured.

In the above-described embodiment, A /
The detection component output from the E converter 18 may be A / D converted by the control unit 20 to remove the high frequency component to remove the vibration component of the measurement sphere 30. This makes hole 2
The accuracy of measuring the inner diameter of 2A (or 22B) can be further improved.

Further, although the above-described embodiment has been described by taking the example of measuring the inner diameters of the linearly formed holes 22A to 22D, the present invention is, for example, a hole formed in a T shape or an L shape. The inner diameter of may be measured.

Further, in the above-described embodiment, when the arm 36 is provided so as to be slidable in the vertical direction with respect to the support column 38, the support members 32 and 68 can be easily put in and taken out from the holes 22A to 22D.

[0082]

As described above, according to the hole inner diameter measuring method and apparatus according to the present invention, the float is inserted into the hole formed in the work to supply the fluid, and the back pressure and the flow rate of the supplied fluid are supplied. Alternatively, the inner diameter of the hole is measured by detecting the drag force received by the float or the displacement of the float, so that the inner diameter of the hole can be accurately measured without causing an eccentricity error or an angle error.

[Brief description of drawings]

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

FIG. 2 is a sectional view showing a characteristic part of the hole inner diameter measuring device shown in FIG.

FIG. 3 is an explanatory view showing an operation of the hole inner diameter measuring device shown in FIG.

FIG. 4 is a block diagram showing the structure of a second embodiment of the hole inner diameter measuring device according to the present invention.

FIG. 5 is a block diagram showing the structure of a measuring device having a detection method different from that of FIG.

FIG. 6 is a cross-sectional view showing a supporting structure of a measuring sphere different from that in FIG.

FIG. 7 is a cross-sectional view showing a supporting structure of a measuring sphere different from that in FIG.

FIG. 8 is a cross-sectional view showing a supporting structure of a measuring sphere different from that in FIG.

9 is a cross-sectional view showing a support structure for a measuring sphere different from that in FIG.

FIG. 10 is a block diagram showing the structure of a third embodiment of the hole inner diameter measuring device according to the present invention.

11 is a cross-sectional view showing a characteristic part of the hole inner diameter measuring device shown in FIG.

FIG. 12 is a cross-sectional view showing an application example of the hole inner diameter measuring device shown in FIG.

FIG. 13 is a sectional view showing an example of a float suitable for a round hole.

FIG. 14 is a sectional view showing an example of a float suitable for a round hole.

FIG. 15 is a sectional view showing an example of a float suitable for a round hole.

FIG. 16 is a sectional view showing an example of a float suitable for a round hole.

FIG. 17 is a sectional view showing an example of a float suitable for a round hole.

FIG. 18 is a sectional view showing an example of a float suitable for a round hole.

FIG. 19 is a sectional view showing an example of a float suitable for a round hole.

FIG. 20 is a sectional view showing an example of a float suitable for a round hole.

FIG. 21 is a sectional view showing an example of a float suitable for a round hole.

FIG. 22 is an explanatory diagram showing an example of a float suitable for a round hole.

FIG. 23 is a sectional view showing an example of a float suitable for a square hole.

FIG. 24 is a cross-sectional view showing a supporting structure of a measuring sphere different from that in FIG.

FIG. 25 is a cross-sectional view showing a supporting structure for a measuring sphere different from that in FIG.

FIG. 26 is a plan sectional view showing the structure of a conventional device.

FIG. 27 is a vertical cross-sectional view showing the structure of a conventional device.

[Explanation of symbols]

10 ... Measuring device, 12 ... Air source, 16 ... Regulator,
18 ... A / E converter, 20 ... control section, 22 ... work, 2
2A ... hole, 28 ... measuring stand, 28A ... supply port, 30 ... measuring sphere, 32 ... supporting member, 42 ... piezoelectric pickup, 48 ...
Strain gauge, 52 ... Permanent magnet, 54 ... Electromagnet, 60 ... Elastic body

Claims (10)

(57) [Claims] 1. A method for measuring the inner diameter of a hole formed in a workpiece, wherein a fluid is supplied to the hole in which a float is inserted, and the supplied fluid passes through a gap between the inner wall of the hole and the float. Back pressure of fluid,
A method for measuring an inner diameter of a hole, comprising detecting a flow rate, a drag force applied to the float, or a displacement amount of the float, and comparing the detected value with a reference value to convert the inner diameter of the hole. 2. A hole inner diameter measuring device for measuring an inner diameter of a hole formed in a work, a float inserted into the hole, fluid supply means for supplying a fluid to the hole in which the float is inserted, Detection means for detecting a back pressure, a flow rate of the fluid when the fluid supplied by the fluid supply means passes through the gap between the hole inner wall and the float, a drag force received by the float, or a displacement amount of the float, A hole inner diameter measuring device, comprising: a conversion unit that compares a detection value detected by the unit with a reference value to convert the inner diameter of the hole. 3. The hole inner diameter measuring device according to claim 2, wherein the float is formed in a spherical shape. 4. The hole inner diameter measuring device according to claim 2, further comprising a support means for the float. 5. The hole inner diameter measuring device according to claim 4, wherein the float is attached to the supporting means via an elastic body. 6. The hole inner diameter measuring device according to claim 4, wherein the float is supported by the support member by a magnetic force. 7. The hole inner diameter measuring device according to claim 2, wherein the fluid supply port is formed in the float. 8. The hole inner diameter measuring device according to claim 2, wherein a plurality of floats are inserted into the hole. 9. The hole inner diameter measuring device according to claim 2, wherein the fluid is air. 10. The float has a cross-sectional shape in a direction orthogonal to the axis of the hole that is similar to the hole. Or the inner diameter measuring device of the hole according to 9.