JP2001349718A - Outer diameter measuring method and device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a low-cost outer diameter measuring method and device capable of measuring accurately the outer diameter of work. SOLUTION: In this measuring device 10, a reference hole 22A is formed on a head 22, and compressed air is supplied into the reference hole 22A. The work 30 is inserted into the reference hole 22A, and the back pressure at that time is detected by an A/E converter 18. The head 22 is floated and supported by jetting out the compressed air from a nozzle 28A of a base 28. Thus, when an automatic centripetal function works on the work 30, the head 22 is moved relatively with the work 30, to thereby arrange the work 30 in the center of the reference hole 22A.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an outer diameter measuring method and apparatus for measuring the outer diameter of a work.

[0002]

2. Description of the Related Art An air micrometer is one of measuring devices for measuring the outer diameter of a work. In a conventional air micrometer, as shown in FIG. 9, a work 3 is inserted into a hole 2 formed in a measuring head 1 and compressed air is applied to the hole 2 from nozzles 4 and 4 in a direction orthogonal to the axis of the hole 2. Spray on nozzle 4
Detects back pressure. Since the back pressure of the nozzle 4 depends on the distance between the nozzle 4 and the work 3, the detected value can be converted into the outer diameter of the work 3 by comparing it with a master reference value obtained in advance. Such an air micrometer has an advantage that the outer diameter of the work 3 can be measured with high accuracy without contact with the work 3.

[0003]

However, in the conventional air micrometer, the nozzles 4 and 4 must be formed with a small diameter and uniformly in order to obtain high measurement accuracy. Had high drawbacks. Also,
Since the gap between the work 3 and the nozzle 4 must be strictly controlled, the processing procedure of the measuring head 1 is complicated, and the hole 2 is processed after the nozzle 4 is assembled to the measuring head 1.
Further, from this state, the position of the nozzle 4 had to be adjusted.

The present invention has been made in view of such circumstances, and has as its object to provide a low-cost outer diameter measuring method and apparatus which can accurately measure the outer diameter of a work.

[0005]

According to the present invention, there is provided an outer diameter measuring method for measuring an outer diameter of a work, the method comprising the steps of: inserting a work into a hole formed in a head; A work is supported, the head is slidably supported in a direction orthogonal to the hole, and a fluid is supplied to the hole in an axial direction of the hole, and the fluid passes through a gap between the inner wall of the hole and the work. When the back pressure of the fluid, the flow rate, or the drag received by the work, or the amount of displacement of the work,
It is characterized in that the detected value is compared with a reference value and converted into an outer diameter of the work.

According to another aspect of the present invention, there is provided an outer diameter measuring apparatus for measuring an outer diameter of a work, wherein the head has a hole for inserting the work, and the head is perpendicular to the hole. Head support means for supporting the work slidably in the direction, work support means for inserting the work into the hole and supporting the work at the insertion position, and fluid supply for supplying fluid to the hole in the axial direction of the hole Means for detecting the back pressure and flow rate of the fluid when the fluid supplied by the fluid supply means passes through the gap between the inner wall of the hole and the work, or the drag received by the work, or the amount of displacement of the work And a conversion means for comparing a detection value detected by the detection means with a reference value and converting the detected value into an outer diameter of the work.

According to the present invention, the work is inserted into the hole of the head and the work is supported at the insertion position, and the head is slidably supported in a direction perpendicular to the hole. When the automatic centripetal action is applied to the work, the head slides and the work is placed at the center of the hole. Therefore, by detecting the back pressure and flow rate of the fluid, the drag received by the work, or the amount of displacement of the work, the outer diameter of the work can be accurately obtained.

[0008]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of an outer diameter measuring method and apparatus according to the present invention.

FIG. 1 shows a measuring apparatus 10 according to a first embodiment.
FIG. 3 is a block diagram showing the configuration of FIG. The following is an example of measuring the outer diameter of the work 30 formed in a cylindrical shape, but the shape of the work 30 measured by the measuring device 10 is not limited to this, and a sphere, a cone, or a combination thereof is used. Shape, etc.

As shown in FIG. 1, compressed air supplied from an air source 12 is dust-removed by a filter 14, adjusted to a constant pressure by a regulator 16, and then adjusted by an A / E converter 18.
The air is sent to the reference hole 22A in the head 22 via the connector 26 in the axial direction of the reference hole 22A through a throttle provided in the (air / electric converter). The A / E converter 18
The pressure at this time is converted into an electric signal by a built-in bellows and a differential transformer, and output to the control unit 20. When the outer diameter of the work 30 is different, the pressure slightly changes, and the control unit 20 calculates the outer diameter of the work 30 based on the changed electric signal, and displays the calculated data on, for example, a monitor of the control unit 20. .

The compressed air removed by the filter 14 is also supplied to a regulator 24,
After being adjusted to a constant pressure by 4, the air is supplied into the base 28 via the connector 34. The head 22 is placed on the base 28, and the head 22 is levitated and supported by the compressed air.

On the other hand, the work 30 is attached to an arm 36 via a support member 32 made of a rigid body. Arm 3
6 is slidably attached to a gantry 40 via sliders 38, 38, and is screwed with a feed screw 44 connected to a rotating shaft of a motor 42. Thus, when the motor 42 is driven, the feed screw 44 rotates, and the arm 36
Goes 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 3
Adjust the vertical position of 0.

FIG. 2 is a side sectional view of the head 22 and the base 28.

The head 22 is formed in a columnar shape, and has a reference hole 22A formed in the center thereof. A connector 26 is connected to the lower end of the reference hole 22A, and compressed air is supplied to the reference hole 22A via the connector 26. Reference hole 22
A throttle 22B having a small diameter is provided above A, and the compressed air is blown to the outside through a gap between the throttle 22B and the work 30. The inner diameter D of the stop 22B is set by the required sensitivity and the outer diameter d of the work 30 to be measured, and for example, is set so that (D−d) is about 10 to 100 μm. The smaller the value (D−d) is, the higher the sensitivity is. Even if the outer diameter d of the work 30 is slightly changed, the detection value of the A / E converter 18 is greatly changed.

On the other hand, the base 28 is formed in a cylindrical shape,
A number of nozzles 28A, 28A (only two are shown) are formed on the upper surface. Multiple nozzles 28A, 28A
Are arranged circumferentially at equal intervals around a hole 28B of the base 28, and communicate with the connector 34 via the internal flow path 28C. The head 22 is placed on the base 28, and the connector 26 and the air hole 27 are arranged inside the hole 28B. Thereby, the reference hole 2 is
When the compressed air is supplied to the nozzle 2A, the compressed air is jetted from the nozzles 28A, 28A substantially uniformly toward the lower surface of the head 22, and the head 22 is supported in a floating state.

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

First, the motor 42 shown in FIG. 1 is driven to lower the arm 36, and the work 30 is inserted into the reference hole 22 A of the head 22. Work 3 inserted in reference hole 22A
0 is supported by the support member 32 at the insertion position.

Next, the air source 12 is driven, and the compressed air adjusted to a constant pressure by the regulators 16 and 24 is
Head 22 and base 28 are supplied.

The compressed air supplied to the base 28 is uniformly jetted from a number of nozzles 28A, 28A to the lower surface of the head 22. As a result, the head 22 is supported by the compressed air in a floating state, and is slidable in a direction perpendicular to the axis of the reference hole 22A (that is, in the horizontal direction).

On the other hand, the compressed air supplied to the head 22 is jetted from the connector 26 to the reference hole 22A in the axial direction of the reference hole 22A. The injected compressed air is the work 3
It blows out from the upper opening through the gap between 0 and the stop 22B. The back pressure at this time is determined by the work 30 and the throttle 22
The back pressure is detected by the A / E converter 18 and the control unit 20 compares the detected value with the master reference value. It can be converted to an outer diameter of 30. 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 work 30 has an aperture 22
An automatic centripetal action (or an automatic centering action) works by the compressed air passing through the gap between B and the work 30. Work 30
Is fixed by the support member 32, the head 22 supported by the floating moves relative to the work 30, whereby the work 30 is arranged at the center of the reference hole 22A. Therefore, the compressed air passes through the gap formed substantially uniformly around the work 30. By detecting the back pressure at this time, the outer diameter of the work 30 can be accurately measured.

As described above, according to the measuring apparatus 10 of the present embodiment, since the head 22 is levitated and supported by the compressed air, the head 22 slides in the horizontal direction, and the work 30 automatically moves to the center of the reference hole 22A. Be placed. Therefore, the outer diameter of the work 30 can be accurately measured.

By the way, the work 30 is automatically moved to the reference hole 2.
In order to arrange the work 30 at the center of 2A, the work 30 may be slidably supported. For example, the support member 3
2 may be provided with a floating mechanism. However, in this case, the weight of the support member 32 increases, and the load applied to the arm 36 increases, so that the size of the entire apparatus increases. On the other hand, in the measuring apparatus 10, since it is not necessary to provide a floating mechanism or the like on the support member 32, the load on the arm 36 is small, and the entire apparatus can be downsized.

Since the measuring device 10 has the aperture 22B in the reference hole 22A, the work 30 can always be measured with a constant accuracy. That is, the detection value of the A / E converter 18 changes only depending on the outer diameter d of the work 30 and the inner diameter D of the stop 22B, and does not depend on the insertion amount of the work 30.
The outer diameter of the work 30 can always be measured with a constant accuracy without controlling the insertion amount of the work 30 with high accuracy.

In the above-described embodiment, the back pressure is detected. However, the present invention is not limited to this, and the flow rate of the compressed air may be detected. Also in this case, similarly to the above-described measuring device 10, the control unit 20 can accurately determine the outer diameter of the work 30 by comparing the detected value with the master reference value.

Further, the resistance of the work 30 and the work 3
A displacement amount of 0 may be detected. Measuring device 48 shown in FIG.
Is a device for detecting the drag received by the work 30, and the supporting member 32 is connected to the arm 36 via the piezoelectric pickup 50.
Attached to. The piezoelectric pickup 50 detects a drag received by the work 30 from the compressed air, and outputs a detection signal to the control unit 20. Also in this case, the control unit 20 can convert the detected value to the outer diameter of the work 30 by comparing the detected value with the master reference value.

Further, as shown in FIG. 4, the displacement of the work 30 may be detected. That is, the support member 32 is connected to the arm 3
6 through the hole 36A formed in the bearing (not shown)
The support member 32 is slidably supported in the vertical direction by the above method. Then, the upper end of the support member 32 is
, And the displacement of the work 30 is detected by the linear scale 46. The work 30 floats and stops at a position where the resistance of the compressed air to lift the work 30 and the weight of the work 30 and the support member 32 are opposed. Therefore, when the outer diameter of the work 30 changes, the drag for lifting the work 30 naturally changes, and the rest position of the work 30 also changes. Therefore, the displacement of the work 30 is detected by the linear scale 46, and the detected value can be converted into the outer diameter of the work 30 by comparing the detected value with the master reference value.

The shapes of the head 22 and the base 28 are as follows.
The present invention is not limited to the above embodiment. For example, in the head 56 shown in FIG. 5, a ridge 56B is formed on the entire outer peripheral surface. On the other hand, the base 58 is a hydrostatic fluid bearing, and floats and supports the head 56 by blowing the compressed air supplied from the regulator 24 onto the upper and lower surfaces of the ridge 56B. As a result, the head 56 slides in the horizontal direction, so that the work 30 subjected to the automatic centripetal action is arranged at the center of the reference hole 56A.

In the embodiment described above, the head 2
2 is floated and supported by the floating mechanism, but any structure may be used as long as the head 22 slides in a direction perpendicular to the axis of the hole 22A. For example, as shown in FIG.
Three or more balls 66, 66 (only two are shown) may be arranged between the base 2 and the base 28. This head 22 holds the ball 6
As 6, 6 rolls, they slide horizontally. The rolling range of the balls 66, 66 is regulated by a ring-shaped regulating member 68.

The head 22 may be moved in a substantially horizontal direction by suspending the head 22 with a string (not shown) or the like.

The support member 32 only needs to support the work 30 in a detachable manner. For example, the end of the work 30 may be clamped by a clamp mechanism. When the work 30 is a magnetic material, a magnet may be provided at the lower end of the support member 32 to attract and support the work 30. Alternatively, the work 30 may be bonded to the support member 32 with an adhesive or the like, and heated when the work 30 is removed. Further, as shown in FIG. 5, the support member 60 may be formed in a cylindrical shape, and the inside of the support member 60 may communicate with the negative pressure generation source 62. In this case, by driving the negative pressure generating source 62, air is sucked, and the work 30 is suction-supported. Reference numeral 64 in FIG. 5 is a ring-shaped sealing material made of rubber or the like, which prevents the workpiece 30 from falling off.

In the embodiment described above, the reference hole 22
Although the stop 22B is provided in A, as shown in FIG. 5, a cylindrical reference hole 56A without the stop 22B may be used. In this case, the inner diameter D1 of the reference hole 56A is set to a value slightly larger than the outer diameter d of the work 30 similarly to the inner diameter D shown in FIG. Thereby, the outer diameter of the work 30 can be measured.

7 and 8 are attached to the tip of the work 30.
The centripetal members 70 and 72 shown in FIG. 7 may be attached to effectively obtain an automatic centripetal effect. The centripetal member 70 shown in FIG. 7 is formed in a hemispherical shape, and the centripetal member 72 shown in FIG. 8 is formed in a conical shape. This centripetal member 7
Numerals 0 and 72 are detachably attached to the work by adhesion that is easily peeled off, or by magnetic force or the like. Thereby, the resistance of the work 30 is reduced, and the compressed air is
Since it is easy to flow evenly on the outer peripheral portion, the automatic centripetal action can be effectively obtained. Therefore, the work 30 has the reference hole 2
Since it is easy to be arranged at the center of 2A, the measurement accuracy is improved. Note that the shapes of the centripetal members 70 and 72 are not limited to those described above, and may be any shape as long as the fluid flows substantially evenly around the work 30.
Alternatively, it may be a polygonal pyramid or the like.

In the embodiment described above, the head 22
Although compressed air is injected into the reference hole 22A, a gas or liquid other than air may be injected. Further, a temperature control means for controlling the temperature of the fluid may be provided.

In the above embodiment, A /
The detection signal output from the E converter 18 may be A / D-converted by the control unit 20 to remove high-frequency components, thereby removing the vibration component of the work 30. Thereby, the measurement accuracy can be further improved.

[0037]

As described above, according to the outer diameter measuring apparatus of the present invention, a work is inserted into the hole of the head and supported at the insertion position, and the head is slidable in a direction perpendicular to the hole. Since the work is supported, the work subjected to the automatic centripetal action is automatically arranged at the center of the hole, and the outer diameter of the work is accurately measured.

[Brief description of the drawings]

FIG. 1 is a block diagram showing the structure of an embodiment of an outer diameter measuring device according to the present invention.

FIG. 2 is a side sectional view showing a head and a base.

FIG. 3 is a block diagram showing an outer diameter measuring device having detecting means different from that of FIG. 1;

FIG. 4 is a side view showing a characteristic portion of the outer diameter measuring device having a detecting means different from that of FIG. 1;

FIG. 5 is a side sectional view showing a head and a base having different shapes from those of FIG. 2;

FIG. 6 is a side sectional view showing a head support structure different from that of FIG. 2;

FIG. 7 is a side view showing an example of a centripetal member attached to a work.

FIG. 8 is a side view showing an example of a centripetal member attached to a work.

FIG. 9 is a 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 unit, 22 ... Head, 2
2A: Reference hole, 22B: Aperture, 28: Base, 28A ...
Nozzle, 30 work, 32 support member, 36 arm, 42 motor, 44 feed screw, 46 linear scale, 70, 72 centripetal member

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Kazuo Nakajima 9-7-1, Shimorenjaku, Mitaka-shi, Tokyo F-term (reference) 2F066 AA22 BB06 FF08 FF09 FF40 HH02 HH10 HH12 JJ12 MM03

Claims (2)

[Claims] 1. An outer diameter measuring method for measuring an outer diameter of a work, comprising: inserting a work into a hole formed in a head, supporting the work at the insertion position, and moving the head in a direction orthogonal to the hole. It is slidably supported and supplies fluid to the hole in the axial direction of the hole, and the back pressure and flow rate of the fluid when the fluid passes through the gap between the hole inner wall and the work, or the drag received by the work Alternatively, an outer diameter measuring method comprising: detecting a displacement amount of the work; comparing the detected value with a reference value; and converting the detected value into an outer diameter of the work. 2. An outer diameter measuring apparatus for measuring an outer diameter of a work, comprising: a head having a hole into which the work is inserted; and a head supporting means for slidably supporting the head in a direction orthogonal to the hole. A work supporting means for inserting the work into the hole and supporting the work at the insertion position; a fluid supply means for supplying a fluid to the hole in an axial direction of the hole; a fluid supplied by the fluid supply means Detecting means for detecting the back pressure of the fluid when passing through the gap between the hole inner wall and the work, the flow rate, or the drag received by the work, or the amount of displacement of the work, and detecting the detection value detected by the detecting means. A conversion means for converting the work into an outer diameter of the work by comparing with a reference value.