JP3390968B2 - Outer diameter measuring method and device - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD 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 the 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 from nozzles 4 and 4 is inserted into the hole 2 in a direction orthogonal to the axis of the hole 2. Nozzle 4
To detect the back pressure of. 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 dimension of the work 3 by comparing with the reference value of the master 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 contacting the work 3.

[0003]

However, in the conventional air micrometer, in order to obtain high measurement accuracy, the nozzles 4 and 4 must be machined with a small diameter and evenly. There was a high drawback. 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.
Furthermore, the position of the nozzle 4 had to be adjusted from this state.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a low cost outer diameter measuring method and apparatus capable of accurately measuring the outer diameter of a work.

[0005]

In order to achieve the above object, the present invention provides an outer diameter measuring method for measuring an outer diameter of a work, wherein the work is inserted into a hole formed in a head, and the work is performed at the insertion position. A work is supported, the head is slidably supported in a direction orthogonal to the hole, 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. The back pressure of the fluid, the flow rate, or the drag force received by the work, or the displacement of the work is detected,
The detected value is compared with a reference value and converted into the outer diameter of the work.

In order to achieve the above object, the present invention provides an outer diameter measuring device for measuring an outer diameter of a work, wherein a head having a hole into which the work is inserted is formed, and the head is orthogonal to the hole. Head support means for slidably supporting the work, 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 and a detection means for detecting a back pressure of the fluid, a 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, a drag force received by the work, or a displacement amount of the work. And a conversion means for comparing a detection value detected by the detection means with a reference value to convert the outer diameter of the work.

According to the present invention, since the work is inserted into the hole of the head to support the work at the insertion position and the head is slidably supported in the direction orthogonal to the hole, the fluid is supplied to the hole. When the work is automatically centered, the head slides and the work is placed in the center of the hole. Therefore, the outer diameter dimension of the work can be accurately obtained by detecting the back pressure of the fluid, the flow rate, the drag force applied to the work, or the displacement of the work.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of an outer 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. 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 of them. It may have a different shape.

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 sent to the reference hole 22A in the head 22 in the axial direction of the reference hole 22A through the connector 26 through the throttle provided in the (air / electric converter). The A / E converter 18 is
The pressure at this time is converted into an electric signal by the built-in bellows and the 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 the monitor of the control unit 20, for example. .

The compressed air removed by the filter 14 is also supplied to the regulator 24, and the regulator 2
After being adjusted to a constant pressure by 4, the air is fed into the base 28 via the connector 34. The head 22 is mounted on the base 28, and the head 22 is levitationally supported by the compressed air.

On the other hand, the work 30 is attached to the arm 36 via a supporting member 32 made of a rigid body. Arm 3
6 is slidably attached to a mount 40 via sliders 38, 38, and a feed screw 44 connected to a rotation shaft of a motor 42 is screwed. As a result, when the motor 42 is driven, the feed screw 44 rotates and the arm 36
Moves up and down.

Above the arm 36, the linear scale 4
6 is provided. Linear scale 46 is arm 3
The lift amount of 6 is detected, and the detection signal is output to the control unit 20. The control unit 20 determines the motor 4 based on this detection signal.
2 is controlled to drive the arm 36 up and down, 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 a reference hole 22A is 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 on the upper portion of 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 diaphragm 22B is set according to the required sensitivity and the outer diameter d of the workpiece 30 to be measured, and is set such that (D−d) is about 10 to 100 μm, for example. The smaller (D-d) is, the better the sensitivity is, and even if the outer diameter d of the work 30 is slightly changed, the detected value of the A / E converter 18 is largely changed.

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

Next, the operation of the measuring apparatus 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 22A of the head 22. Workpiece 3 inserted in the reference hole 22A
0 is supported at its insertion position by the support member 32.

Next, the air source 12 is driven, and the compressed air adjusted to a constant pressure by the regulators 16 and 24, respectively,
Supply to the head 22 and the base 28.

The compressed air supplied to the base 28 is evenly jetted from the numerous nozzles 28A, 28A to the lower surface of the head 22. As a result, the head 22 is supported in a state of being floated by the compressed air and is slidable in the direction orthogonal to the axis of the reference hole 22A (that is, 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 passes through the gap between 0 and the diaphragm 22B and blows out from the upper opening. The back pressure at this time is the work 30 and the diaphragm 22.
Since it depends on the size of the gap with B, that is, the outer diameter of the work 30, the back pressure is detected by the A / E converter 18, and the control unit 20 compares the detected value with the reference value of the master to determine the work. 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 condition is changed.

A diaphragm 22 is attached to the work 30 during measurement.
The compressed air passing through the gap between B and the work 30 causes an automatic centripetal action (or self-aligning action). Work 30
Is fixed by the support member 32, the head 22 which is levitationally supported moves relative to the work 30, and the work 30 is arranged at the center of the reference hole 22A. Therefore, the compressed air passes through the gaps formed approximately uniformly around the work 30, and the outer diameter of the work 30 can be accurately measured by detecting the back pressure at this time.

As described above, according to the measuring apparatus 10 of the present embodiment, since the head 22 is levitationally 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. Will 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 dispose the work 30 at the center of 2A, it is possible to support the work 30 slidably. For example, the support member 3
It is conceivable to provide a floating mechanism in 2. However, in this case, the weight of the support member 32 is increased and the load applied to the arm 36 is increased, so that the size of the entire apparatus is increased. On the other hand, in the measuring device 10, since it is not necessary to provide the support member 32 with a floating mechanism or the like, the load on the arm 36 is small, and the entire device can be downsized.

Further, since the measuring device 10 is provided with the diaphragm 22B in the reference hole 22A, the work 30 can always be measured with a constant accuracy. That is, the detected value of the A / E converter 18 changes only by the outer diameter d of the work 30 and the inner diameter D of the diaphragm 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 workpiece 30 with high accuracy.

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

Further, the work force received by 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 reaction force received by the work 30, and the support member 32 is connected to the arm 36 via the piezoelectric pickup 50.
Is attached to. The piezoelectric pickup 50 detects the reaction force received by the work 30 from the compressed air and outputs the detection signal to the control unit 20. Also in this case, the control unit 20 can convert the detected value into the outer diameter of the work 30 by comparing the detected value with the reference value of the master.

Further, as shown in FIG. 4, the displacement amount of the work 30 may be detected. That is, the support member 32 is attached to the arm 3
Bearings (not shown) are passed through holes 36A formed in 6
The supporting member 32 is slidably supported in the vertical direction. Then, the upper end of the support member 32 is attached to the linear scale 46.
The linear scale 46 detects the displacement amount of the work 30. The work 30 floats and stands at a position where the drag force of the compressed air to lift the work 30 and the weight of the work 30 and the support member 32 compete with each other. Therefore, when the outer diameter of the work 30 changes, the drag force for lifting the work 30 naturally changes, and the stationary position of the work 30 also changes. Therefore, the displacement amount 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 reference value of the master.

The shapes of the head 22 and the base 28 are
The present invention is not limited to the above embodiment. For example, in the head 56 shown in FIG. 5, the convex stripe portion 56B is formed on the entire outer peripheral surface. On the other hand, the base 58 is a hydrostatic bearing, and blows the compressed air sent from the regulator 24 onto the upper surface and the lower surface of the protruding portion 56B to support the head 56 in a floating manner. 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.

Further, in the above-described embodiment, the head 2
Although 2 is levitationally supported by a floating mechanism, any structure may be used as long as the head 22 slides in a direction orthogonal 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 2 and the base 28. This head 22 is a ball 6
When 6, 66 roll, 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 may be any member that supports the work 30 in a detachable manner, and may clamp the end of the work 30 by a clamp mechanism, for example. When the work 30 is a magnetic body, 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 adhered 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 adsorbed and supported. Reference numeral 64 in FIG. 5 is a ring-shaped sealing material made of rubber or the like, which prevents the work 30 from falling off.

Further, in the above-described embodiment, the reference hole 22 is used.
Although the diaphragm 22B is provided in A, as shown in FIG. 5, it may be a cylindrical reference hole 56A without the diaphragm 22B. In this case, the inner diameter D1 of the reference hole 56A is set to a value that is 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.

In addition, at the tip of the work 30, FIG.
The centripetal action members 70 and 72 shown in FIG. 7 may be attached to effectively obtain the automatic centripetal action. The centripetal action member 70 shown in FIG. 7 is formed in a hemispherical shape, and the centripetal action member 72 shown in FIG. 8 is formed in a conical shape. This centripetal member 7
Nos. 0 and 72 are detachably attached to the work by adhesion that easily peels off, or by magnetic force or the like. As a result, the resistance of the work piece 30 is reduced and the compressed air is transferred to the work piece 30.
Since it becomes easy to flow evenly to the outer peripheral portion of the, the automatic centripetal action is effectively obtained. Therefore, the work 30 is set in the reference hole 2
Since it is easy to dispose at the center of 2A, the measurement accuracy is improved. The centripetal action members 70 and 72 are not limited to the above-mentioned shapes, and may have any shape as long as the fluid flows around the work 30 substantially evenly, for example, a sphere or a truncated cone.
Alternatively, it may be a polygonal cone or the like.

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

In the above-described embodiment, A /
The vibration signal of the work 30 may be removed by A / D converting the detection signal output from the E converter 18 in the control unit 20 and removing the high frequency component. Thereby, the measurement accuracy can be further improved.

[0037]

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

[Brief description of drawings]

FIG. 1 is a block diagram showing a 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 a detecting means different from that in FIG.

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

5 is a side sectional view showing a head and a base having a different shape from FIG.

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 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 unit, 22 ... Head, 2
2A ... reference hole, 22B ... diaphragm, 28 ... base, 28A ...
Nozzle, 30 ... Workpiece, 32 ... Support member, 36 ... Arm, 42 ... Motor, 44 ... Feed screw, 46 ... Linear scale, 70, 72 ... Centripetal member

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Bibliography No. 2-7510 (JP, U) (58) Fields investigated (Int.Cl. ⁷ , DB name) G01B 13/00-13/24

Claims (2)

(57) [Claims] 1. An outer diameter measuring method for measuring an outer diameter of a work, wherein the work is inserted into a hole formed in a head, the work is supported at the insertion position, and the head is moved in a direction orthogonal to the hole. Supporting slidably, supplying fluid to the hole in the axial direction of the hole, the back pressure, flow rate of the fluid when the fluid passes through the gap between the inner wall of the hole and the work, or the drag force received by the work. Alternatively, the outer diameter measuring method is characterized in that the displacement amount of the work is detected, and the detected value is compared with a reference value to be converted into the outer diameter of the work. 2. An outer diameter measuring device 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 support 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 the axial direction of the hole; and a fluid supplied by the fluid supply means Is a back pressure of the fluid when passing through the gap between the inner wall of the hole and the work, a flow rate, a drag force received by the work, or a detection unit that detects the displacement amount of the work, and a detection value detected by the detection unit. An outer diameter measuring device, comprising: a conversion unit that compares the outer diameter of the work with a reference value.