JP2004061110A - Measurement instrument - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inexpensive non-contact measurement instrument which measures the inner diameter, the straightness, the cylindricity, and so forth of a hole formed in a work. <P>SOLUTION: An air/electricity transducer 30 detects a variation in the back pressure of a gas ejected into the hole WA, when a ball 14 is inserted in an automatic centripetal state into the hole WA of the work W is moved in the longitudinal direction of the hole WA. A light-receiving part 22 receives reflected light from a reflection member 18 provided to the ball 14. It is constituted so that the inner diameter, the straightness, and the cylindricity of the hole WA are obtained by obtaining the the variation in the peak position A in the amount of reflected light. Thus, the inexpensive non-contact measurement instrument 10 which measures the inner diameter, the straightness, and the cylindricity of the hole WA is provided. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a measuring device for measuring a hole formed in a work, and more particularly to a measuring device for measuring the inner diameter, straightness, and cylindricity of a hole in a non-contact manner.
[0002]
[Prior art]
Conventionally, when measuring the inner diameter, straightness, cylindricity, and the like of a hole in a cylindrical part that is widely used as an automobile part, a machine tool part, or the like, an object to be measured (hereinafter referred to as a workpiece ) Is fixed, and a contact-type detector is rotated along the inner surface of the hole and measured while moving the detector in the longitudinal direction of the hole. When the work is a small part, a work rotation type roundness measuring machine has been used.
[0003]
[Problems to be solved by the invention]
However, this roundness measuring device is a general-purpose measuring device, has various functions, and the device itself is expensive. In addition, since the contact type is used, the measurement surface is scratched, and traces of dragging the touch element remain. For this reason, when the measurement pressure is reduced, when there is a burr or a groove on the inner peripheral portion of the hole, the tentacle is caught by the burr or the groove, and the measured value is a factor of variation.
[0004]
The present invention has been made in view of such circumstances, and it is an object of the present invention to provide an inexpensive measuring device capable of measuring the inner diameter, straightness, and cylindricity of a hole formed in a work in a non-contact manner. .
[0005]
[Means for Solving the Problems]
In order to achieve the above object, an invention according to claim 1 is a measuring apparatus for measuring a hole formed in a work, wherein an injection port for holding the work and injecting gas into the hole formed in the work. , A ball inserted into a hole formed in the work, an elastic member supporting the ball, and a pneumatic / electrical converter for converting a change in back pressure of the injected gas into an electric signal. A control unit for determining an inner diameter of the hole by a signal from the pneumatic / electrical converter when the ball is inserted into the hole formed in the work and gas is injected into the hole when the ball is inserted into the hole. It is characterized by being provided.
[0006]
According to the first aspect of the present invention, a gas is injected into a gap formed between the inner peripheral surface of the hole and the ball, a change in back pressure of the injected gas is detected by the pneumatic / electrical converter, and the inner diameter of the hole is determined. Since it is required, a non-contact and inexpensive inner diameter measuring machine can be provided.
[0007]
According to a second aspect of the present invention, there is provided a measuring device for measuring a hole formed in a work, wherein the holding table has an injection port for holding the work and injecting gas into the hole formed in the work. A ball inserted into a hole formed in the workpiece, an elastic member supporting the ball, a reflecting member attached to the ball and reflecting light supplied from a light source, and receiving the reflected light A light-receiving unit, elevating means for moving the elastic member and the ball up and down, inserting the ball into a hole formed in the work, and injecting gas into the hole to form the ball and the hole. And when the ball is moved up and down, the light from the light source reflected by the reflecting member is received by the light receiving section to determine a change in the peak position of the amount of reflected light. true It is characterized in that control unit for determining a degree is provided.
[0008]
According to the invention of claim 2, when the ball inserted into the hole is moved in the longitudinal direction of the hole in a state where the ball is automatically centered, the light receiving portion receives reflected light from a reflecting member provided on the ball, Since the straightness of the hole is obtained by obtaining the change in the peak position of the reflected light amount, it is possible to provide a non-contact and inexpensive hole straightness measuring device.
[0009]
Further, the invention according to claim 3 is a measuring apparatus for measuring a hole formed in a work, wherein the holding table has an injection port for holding the work and injecting gas into the hole formed in the work. A ball inserted into a hole formed in the work, an elastic member supporting the ball, a pneumatic / electrical converter for converting a change in back pressure of the injected gas into an electric signal, A reflecting member that is attached and reflects light supplied from the light source, a light receiving unit that receives the reflected light, and an elevating unit that moves the elastic member and the ball up and down; and The ball is inserted into the formed hole, gas is injected into the hole to automatically center the ball and the hole, and a signal from the pneumatic / electrical converter when the ball is moved up and down. , By the reflecting member From the change data of the peak position of the reflected light at the light receiving section receives light from Isa light source, is characterized in that control unit is provided to determine the cylindricity of the hole.
[0010]
According to the third aspect of the present invention, when the ball inserted into the hole is moved in the longitudinal direction of the hole while being automatically centered, the change in the back pressure of the gas injected into the hole is measured by the pneumatic / electrical converter. And the reflected light from the reflecting member provided on the ball is received by the light receiving unit, and the change in the peak position of the reflected light amount is determined to determine the cylindricity of the hole. A cylindricity measuring machine can be provided.
[0011]
According to a fourth aspect of the present invention, in the second or third aspect, the reflecting member is a corner cube. According to the fourth aspect of the present invention, since the corner cube is used as the reflecting member, the light emitted from the light source always has the same incident angle and the same outgoing angle, and the amount of reflected light even when the ball is tilted when the ball is moved up and down. The change of the peak position can be accurately detected.
[0012]
According to a fifth aspect of the present invention, in the second or third aspect, the elastic member is a parallel spring composed of at least three linear elastic bodies. According to the fifth aspect of the present invention, since the ball is supported by the parallel spring made of at least three linear elastic members, the ball does not tilt even if the axis of the hole is bent, and the reflected light amount is reduced. A change in the peak position can be accurately detected.
[0013]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, preferred embodiments of a measuring apparatus according to the present invention will be described in detail with reference to the accompanying drawings. In the drawings, the same members are given the same numbers or reference numerals.
[0014]
FIG. 1 is a sectional view showing the concept of a measuring device for measuring holes formed in a work according to the present invention. As shown in FIG. 1, the measuring device 10 includes a holding table 12 for holding a work W, a ball 14 having a diameter slightly smaller than the inside diameter of a hole WA formed in the work W, and an elastic member having the ball 14 fixed to the tip. 16, lifting / lowering means 26 connected to the other end of the elastic member 16 to move the elastic member 16 and the ball 14 up and down, a pneumatic / electrical converter 30, a reflecting member 18 attached to the upper part of the ball 14, a light source 20, a light receiving section 22 , A half mirror 24, a control unit 40, and the like.
[0015]
As the ball 14, a steel ball having good sphericity is used, and a piano wire is used as the elastic member 16 whose tip is fixed to the ball 14 and supports the ball 14. The elevating means 26 includes a known linear guide, a ball screw, a stepping motor, and the like, and is controlled by the control unit 40 to move the elastic member 16 and the ball 14 up and down.
[0016]
The holding table 12 is formed with an ejection port 12A for ejecting air toward the hole WA of the workpiece W to be measured, and an air supply port 12B communicating with the ejection port 12A. Compressed air is supplied to the air supply port 12B via the pneumatic / electrical converter 30, and the supplied air is injected from the injection port 12A toward the hole WA of the work W.
[0017]
An air / electric converter 30 (hereinafter, referred to as an A / E converter 30) is a device that converts a change in back pressure of supplied air into an electric signal using a bellows and a differential transformer, and converts the converted electric signal. Is sent to the control unit 40.
[0018]
The half mirror 24 reflects substantially half of the light projected from the light source 20 to irradiate the reflecting member 18, and transmits substantially half of the reflected light from the reflecting member 18 to irradiate the light receiving unit 22. A CCD is used as the light receiving unit 22 so that the peak position of the reflected light amount is detected. Alternatively, the peak position of the amount of reflected light is calculated by the control unit 40 using a four-divided photocell without using a CCD. A laser or a halogen lamp is used as a light source, and the collimated light is emitted.
[0019]
The injection port 12 </ b> A formed in the holding table 12 is a through hole, and the elastic member 16 supporting the ball 14 is inserted therethrough. A sealing material 29 is attached to the lower end of the injection port 12A to prevent air from leaking from a gap between the elastic member 16 and the injection port 12A. Further, a seal member 28 is similarly attached to the upper surface of the holding table 12 to seal a gap between the work W and the upper surface of the holding table 12 when the work W is pressed and fixed to the holding table 12 by pressing means (not shown). ing.
[0020]
The control unit 40 controls the operation of each unit of the measuring device 10 and also performs arithmetic processing on the signal from the A / E converter 30 and the signal from the light receiving unit 22 to obtain a measured value.
[0021]
Next, the operation of the measuring device 10 thus configured will be described. First, a work W to be measured is placed on the holding table 12. At this time, the space between the lower surface of the work W and the upper surface of the holding table 12 is sealed with the sealant 28. Then the ball 14 is inserted into the hole WA of elevated work W by the lifting means 26, ⁰ is positioned at a predetermined position then the air supply port 12B of the holding compressed air via the A / E converter 30 base 12 From the jet port 12A, and is jetted into the hole WA of the workpiece W. The supplied air is discharged upward through a gap formed by the hole WA and the ball 14. At this time, the ball 14 supported by the elastic member 16 is only cantilevered by the elastic member 16, and is automatically centered on the center of the hole WA by the action of the air flowing through the gap.
[0022]
In the A / E converter 30, a change in back pressure caused by the size of the gap formed between the hole WA and the ball 14 is converted into an electric signal and sent to the control unit 40. The control unit 40 calculates the inner diameter of the hole WA of the work W from the signal from the A / E converter 30. Prior to the measurement, the magnification of the A / E converter 30 is calibrated using two types of masters whose exact inside diameters of the holes are known.
[0023]
Next, the ball 14 is moved by the elevating means 26, the inner diameter of the hole WA at a plurality of positions is measured, and a simple cylindricity of the hole WA is obtained.
[0024]
The reflecting member 18 attached to the top of the ball 14 has a circular shape, and the reflecting member 18 is irradiated with parallel rays from a light source 20 via a half mirror 24. The irradiated light is reflected and received by the light receiving section 22. Since the light receiving section 22 is constituted by a CCD or a four-segment photocell, a peak position A of the amount of light reflected by the reflecting member 18 as shown in FIG. 2 is obtained.
[0025]
FIG. 3 shows a state where reflected light is applied when the four-divided photocell 22A is used as the light receiving unit 22. The peak position A of the reflected light amount is calculated from the output distribution of each of the four photocells. That is, the center of the circle having the area ratio corresponding to the ratio of the output value of each photocell is obtained as the peak position A of the reflected light amount.
[0026]
The straightness of the hole WA is calculated by moving the ball 14 in the longitudinal direction of the hole WA of the workpiece W using the automatic centripetal action of the ball 14 by air and calculating the displacement of the peak position A of the reflected light amount. You. Further, from the straightness data when the ball 14 is moved in the longitudinal direction of the hole WA and the inner diameter data by the A / E converter 30 at each position in the longitudinal direction of the hole WA, a straightness component of the hole WA is included. Cylindricity is required. These measurement values are all calculated and obtained by the control unit 40.
[0027]
FIG. 4 shows a case where a corner cube 18 </ b> A is used as the reflection member 18. As shown in FIG. 4, when the hole WA of the work W is bent, the ball 14 is automatically centered while being supported by the elastic member 16 in a cantilever manner, and thus slightly tilts. When the reflecting member 18 is a plane mirror, the plane mirror is also slightly tilted when the ball is slightly tilted, and the irradiation light amount peak position on the light receiving unit 22 is slightly shifted, which causes a slight error in straightness measurement.
[0028]
However, if the reflecting member 18 is a corner cube 18A as shown in FIG. 4, the angle of incidence of light on the corner cube 18A and the angle of reflection are always the same. The straightness of the hole WA can be obtained with higher accuracy without shifting the peak position. In FIG. 4, the illustration of the A / E converter 30, the light source 20, and the control unit 40 is omitted. (Hereinafter, also in FIG. 5, the description of the A / E converter 30, the light source 20, and the control unit 40 is omitted.)
FIG. 5 shows a case where a parallel spring composed of three piano wires arranged at equal circumferential intervals and parallel to each other is used as the elastic member 16. FIG. 5A shows a state where the hole WA of the work W is straight, and FIG. 5B shows a state where the hole WA of the work W is bent. Since the elastic member 16 holding the ball 14 forms a parallel spring with three piano wires, as shown in FIG. 5B, even if the hole WA of the work W is bent, the reflecting member 18 4 does not incline, and even if the reflecting member 18 is a plane mirror, no error occurs in the detection of the peak position of the amount of reflected light on the light receiving section 22, and the straightness of the hole WA is more precisely straightened as in the case of FIG. Degree can be determined.
[0029]
In the above embodiment according to the present invention described, but using compressed air for automatic centripetal action of internal diameter measurement and the ball 14 to be measured hole WA, not limited thereto, N ₂ gas or Ar gas or the like, It can be selected as appropriate.
[0030]
【The invention's effect】
As described above, according to the measuring device for measuring the hole of the present invention, the inner diameter of the hole is measured by detecting the change in the back pressure of the gas due to the size of the gap between the hole and the ball inserted into the hole, When the hole is moved along the hole, the straightness of the hole is measured from the automatic centripetal action between the hole and the ball due to the flow of gas and the displacement of the peak position of the amount of reflected light from the reflecting member attached to the ball. Since the cylindricity of the hole is calculated from both the measurement data, an inexpensive hole measuring device capable of measuring the inner diameter, straightness, and cylindricity of the hole without contact is obtained.
[Brief description of the drawings]
FIG. 1 is a sectional view showing a hole measuring device according to an embodiment of the present invention. FIG. 2 is a graph showing the amount of reflected light at a light receiving section. FIG. 3 is a plan view showing reflected light on a four-divided photocell. FIG. 4 is a sectional view of a case where a corner cube is used as a reflecting member. FIG. 5 is a sectional view of a case where a parallel spring is used as an elastic member.
DESCRIPTION OF SYMBOLS 10 ... Measuring device, 12 ... Holder, 12A ... Injection port, 14 ... Ball, 16 ... Elastic member, 16A ... Parallel spring, 18 ... Reflection member, 18A ... Corner cube, 18B ... Mirror, 20 ... Light source, 22 ... Light reception Part, 24: half mirror, 26: elevating means, 28, 29: sealing material, 30: A / E converter (pneumatic / electrical converter), 40: control unit, A: peak position of light quantity, W: work, WA ... hole

Claims (5)

In a measuring device for measuring a hole formed in a work,
A holding table provided with an injection port for holding the work and injecting gas into holes formed in the work,
A ball inserted into a hole formed in the work,
An elastic member supporting the ball,
A pneumatic / electrical converter for converting a change in back pressure of the injected gas into an electric signal,
A control unit for determining the inner diameter of the hole by a signal from the pneumatic / electrical converter when the ball is inserted into the hole formed in the work and gas is injected into the hole is provided. Measuring device. In a measuring device for measuring a hole formed in a work,
A holding table provided with an injection port for holding the work and injecting gas into holes formed in the work,
A ball inserted into a hole formed in the work,
An elastic member supporting the ball,
A reflecting member that is attached to the ball and reflects light supplied from a light source,
A light receiving unit that receives the reflected light,
Lifting means for moving the elastic member and the ball up and down,
The ball was inserted into the hole formed in the work, and the ball and the hole were automatically centered by injecting gas into the hole, and the ball was reflected by the reflecting member when the ball was moved up and down. A measuring device, comprising: a control unit for receiving a light from a light source at the light receiving unit to obtain a change in a peak position of a reflected light amount, thereby obtaining a straightness of the hole. In a measuring device for measuring a hole formed in a work,
A holding table provided with an injection port for holding the work and injecting gas into holes formed in the work,
A ball inserted into a hole formed in the work,
An elastic member supporting the ball,
A pneumatic / electrical converter for converting a change in back pressure of the injected gas into an electric signal;
A reflecting member that is attached to the ball and reflects light supplied from a light source,
A light receiving unit that receives the reflected light,
Lifting means for moving the elastic member and the ball up and down,
The ball is inserted into a hole formed in the work, and gas is injected into the hole to automatically center the ball and the hole, and when the ball is moved up and down, And a control unit for obtaining the cylindricity of the hole from the data of the peak position of the amount of light reflected by the light receiving unit that has received light from the light source reflected by the reflecting member. Characteristic measuring device. The measuring device according to claim 2, wherein the reflecting member is a corner cube. The measuring device according to claim 2, wherein the elastic member is a parallel spring including at least three linear elastic bodies.

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