JP2001349719A - Pneumatic micrometer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pneumatic micrometer capable of executing accurate inner diameter measurement, even if irregular stripes are formed on the inner surface such as a spline coupling. SOLUTION: This pneumatic micrometer is so formed that a nozzle hole 3 for jetting out the air is formed on the surface of a measuring head 2 inserted in the non-contact state into a work hole part 1 whose inner diameter is required to be measured, and that the change of a flow rate or the pressure of the air changing by an aperture between the nozzle hole 3 of the measuring head 2 and the inner surface of the work hole part 1 is converted into the aperture size, to thereby measure the inner diameter of the work hole part 1. In the micrometer, the nozzle hole 3 is formed not as a round hole but as a slit-shaped nozzle hole 3, and the length direction of the slit-shaped nozzle hole 3 when the measuring head 2 is inserted into the work hole part 1 is not set in the direction crossing a part where the aperture size is not proportional to the change of the air caused by air leakage from the inner surface where the inner diameter is required to be measured such as a work external part outside the edge part of the work hole part 1, a groove part on the inner surface of the hole part or the like, but set in the direction along the inner diameter measuring part having a fixed aperture with the nozzle hole 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to an air micrometer.

[0002]

2. Description of the Related Art When compressed air is applied to an object to be measured, a flow rate and a pressure of the air change due to a gap between a nozzle hole from which air is ejected and a surface of the object to be measured. .

A system that indicates this change in air as the size of a gap is an air micrometer.

That is, a nozzle hole for ejecting air is provided on the surface of a measuring head which is inserted in a non-contact state into a work hole whose inner diameter is to be measured, and a gap between the nozzle hole of the measuring head and the inner surface of the work hole is provided. The apparatus is configured to convert a change in the changing flow rate or pressure of air into the gap size and measure the inner diameter of the work hole.

As a nozzle hole on the surface of a measurement head used for a measurement portion of such an air micrometer, a hole having a diameter of about 1 mm to 2 mm is usually used.

[0006] The diameter of the hole and the gap with the surface to be measured are important parameters that determine the performance of the air micrometer. Each manufacturer has practical combinations as know-how based on many experiments and calculations. Although selected according to the conditions, the air ejected from this nozzle hole must flow uniformly into the gap with the surface to be measured, and the surface to be measured must be large enough for the nozzle hole. If not, correct measurement cannot be performed.

For example, when the inner diameter of a work hole is measured with an air micrometer having a normal nozzle hole, the thickness of the part (work) is shorter than 3 mm (the work is thin). ), The change in the air flow due to the change in the inner diameter may not be detected due to the air leaking from the mouth of the hole of the component to the outside.

[0008] The measurement method using an air micrometer in such a case is as follows. A measuring element such as a leaf type is movably provided in a narrow measuring portion, and the movement of the measuring element movably contacting the inner surface of the measurement by jetting air is measured. 2. A small nozzle hole such as 0.3 mm in diameter is adopted.
Such a method is adopted.

In the case of 1, the measurement cannot be performed in a non-contact state without contacting the measuring element, which is an advantage of the air micrometer, with the inner surface. It is easy for malfunctions to occur due to such factors.

[0010] In addition, mass production is inferior due to an increase in the number of parts, which leads to an increase in cost.

In case (2), since the nozzle hole is small, there is little change in the flow rate or pressure of air with respect to the gap. (The part to be displayed is called the main body.).

That is, when the amount of change becomes small by using the nozzle hole as a small hole, use a main body of a system that electrically expands this small change in air, or use a flow-type accessory to expand the mechanically. It becomes necessary to add it to the main body.

In general, when the diameter of the nozzle hole is small, the measurable range becomes narrow.

In order to solve these problems, the present invention employs a rectangular slit-shaped nozzle hole instead of a round nozzle hole in an air micrometer for measuring the inner diameter, and adjusts the direction of the slit-shaped nozzle hole. By setting it in a predetermined direction according to the work, air leakage is suppressed and the change in air is not reduced by a sufficient flow rate, even if the hole length of the work is short, and the inner surface like a spline joint It is an object of the present invention to provide an epoch-making air micrometer capable of measuring an inner diameter with high accuracy even when an uneven stripe is formed on the air micrometer.

[0015]

The gist of the present invention will be described with reference to the accompanying drawings.

A nozzle hole 3 for ejecting air is provided on the surface of a measuring head 2 which is inserted in a non-contact state into a workpiece hole 1 whose inner diameter is to be measured, and the nozzle hole 3 of the measuring head 2 and the inner surface of the workpiece hole 1 are provided. In the air micrometer configured to measure the inner diameter of the work hole 1 by converting the change in the flow rate or pressure of air that changes due to the gap between the nozzle hole 3 and the nozzle hole 3 into a round hole, The length direction of the slit-shaped nozzle hole 3 when the measuring head 2 is inserted into the work hole 1 is defined as:
The air leaks from the inner surface of the work hole 1 where the inside diameter is to be measured, such as the outside of the work outside the edge of the work hole or the groove on the inner surface of the hole. The air micrometer is characterized in that it is set in a direction along an inner diameter measuring portion having a certain gap with the nozzle hole 3.

In addition, in the nozzle hole having a short length and a large round hole, the work hole 1 leaks air to the outside of the work outside the edge of the work hole 1, and the size of the gap and the change in air change. If the measurement accuracy is deteriorated without being proportional, the measuring head 2
2. The air micrometer according to claim 1, wherein a length direction of the slit-shaped nozzle hole 3 when the workpiece is inserted into the work hole 1 is set to a circumferential direction of an inner surface of the work hole 1. 3. It is related.

In the large round nozzle hole where a large number of concave and convex strips 4 are formed on the inner surface of the work hole 1, air leaks into the groove 4B of the concave and convex strip 4, and the size of the gap and the change in air are reduced. When the measurement accuracy deteriorates without being proportional, the length direction of the slit-shaped nozzle hole 3 when the measuring head 2 is inserted into the work hole 1 intersects with the uneven ridges 4 on the inner surface of the work hole 1. No direction, nozzle hole 3 and work hole 1
The inner surface is set to a direction that matches the length direction of the protruding ridge portion 4A of the concavo-convex ridge 4 having a certain gap, and the slit width of the slit-shaped nozzle hole 3 is set to be greater than the width of the protruding ridge portion 4A. 3. The air micrometer according to claim 1, wherein the air micrometer is set small.

Further, after finishing the finishing of the measuring head 2, the slit-shaped nozzle holes 3 are formed on the surface of the measuring head 2 in predetermined directions and at predetermined positions. The air micrometer according to any one of the above.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION Preferred embodiments of the present invention (how to implement the invention) will be briefly described with reference to the drawings, showing the operational effects thereof.

According to the present invention, by providing a slit-shaped nozzle hole set in a predetermined direction, the same performance as that of a conventional round-hole nozzle hole can be ensured with respect to the flow of air. It can be used with the air micrometer body of
This configuration does not require a movable measuring element such as a leaf that complicates the structure.

That is, both the main body and the measuring head can be manufactured at a low cost, and by combining them, it becomes possible to directly measure a narrow measuring portion, which was impossible in the past, by directly blowing.

The direction in which the nozzle holes 3 are formed (the setting of the length direction of the slit-shaped nozzle holes 3) is determined according to the shape of the part to be measured.

That is, according to the present invention, the nozzle hole 3 is not a round hole but a slit-shaped nozzle hole 3, and the measuring head 2
Slit-shaped nozzle hole 3 when the nozzle is inserted into the work hole 1
In the length direction, air leaks from the inner surface to be measured of the inner diameter such as the outside of the work outside the edge of the work hole 1 or the groove on the inner surface of the hole so that the dimension of the gap is not proportional to the change in air. Instead of the direction intersecting with the nozzle hole 3, the direction is set along a portion having a certain gap with the nozzle hole 3.

Specifically, for example, in the nozzle hole 3 having a short length and a large round hole, the work hole 1 leaks air to the outside of the work outside the mouth edge of the work hole 1, and the dimension of the gap In this case, the measurement accuracy is deteriorated because the change in air is not proportional to the change in air. In such a case, the slit-shaped nozzle hole 3 is used when the measurement head 2 is inserted into the work hole 1. The length direction of the hole 3 is set in the circumferential direction of the inner surface of the work hole 1.

Also, for example, in the case of a large round nozzle hole in which a large number of irregularities 4 are formed on the inner surface of the work hole 1, air leaks into the grooves of the irregularities, and the size of the gap is proportional to the change in air. When the measurement accuracy is deteriorated without performing the measurement, the length direction of the slit-shaped nozzle hole 3 is not set to the direction intersecting the concave and convex stripes on the inner surface of the work hole portion 1 and the gap between the nozzle hole 3 and the inner surface of the work hole portion 1 is constant. Ridges 4 of the ridges 4 having the
The slit width of the slit-shaped nozzle hole 3 is set to be smaller than the width of the ridge 4A. That is, when measuring a portion having a groove in the axial direction such as the inner diameter of a spline, the long side of the slit-shaped nozzle hole 3 is oriented in the axial direction.

Further, for example, by adjusting the direction of the nozzle to a narrow portion of the inner diameter measured in the same manner, the inner diameter can be measured, for example, in the case where a twist groove is formed.

[0028]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Specific embodiments of the present invention will be described with reference to the drawings.

In this embodiment, as shown in FIG. 1, a nozzle hole 3 for ejecting air is provided on the surface of a measuring head 2 inserted in a non-contact state into a work hole 1 whose inner diameter is to be measured. In an air micrometer configured to convert the change in the flow rate or pressure of air, which changes due to the gap between the second nozzle hole 3 and the inner surface of the work hole 1, into the size of the gap to measure the inner diameter of the work hole 1. , Nozzle hole 3
Is not a round hole but a slit-shaped nozzle hole 3 set in a predetermined direction.

For example, the first embodiment shown in FIGS. 2 and 3 is a first embodiment in which the length of the work hole 1 is short, and has a large round hole of about 1 to 2 mm as in the conventional example. In the nozzle hole 3, the jet air leaks out of the work outside the mouth edge of the work hole 1, and the measurement accuracy is deteriorated because the dimension of the gap is not proportional to the change in air. Is formed as a slit-shaped nozzle hole 3 having a width sufficiently smaller than the inner diameter of the hole, so that air leakage to the outside is reduced, and the change in air is proportional to the gap size.

On the other hand, in this case, as described in the conventional example, if the nozzle hole is simply a small round hole, the problem of the leakage can be similarly solved, but the air flow rate decreases and the change amount decreases. In order to solve this problem, the length of the slit-shaped nozzle hole 3 when the measuring head 2 is inserted into the work hole 1 is changed to the length of the work hole. It is set in the circumferential direction of the inner surface of the part 1.

Therefore, both the problem of leakage and the problem of reduced flow rate can be solved at the same time, and a general inexpensive measuring body can be used simply by forming the nozzle holes 3 on the surface of the non-contact type measuring head 2. It becomes a periodical air micrometer.

For example, in the second embodiment shown in FIGS. 4 and 5, a large number of concave and convex stripes 4 are formed on the inner surface of the work hole 1 like a spline. The air leaks into the groove 4B in the same manner as the above-mentioned leak to the outside. In this case as well, the dimension of the gap and the change in air are not proportional, and the measurement accuracy is deteriorated. The length direction of the slit-shaped nozzle hole 3 is
The nozzle hole 3 and the inner surface of the work hole 1 do not have a direction intersecting the protrusions and recesses 4 on the inner surface of the work hole 1 but coincide with the length direction of the protrusion 4A of the protrusion and recess 4 having a constant gap. And the slit width of the slit-shaped nozzle hole 3 is set smaller than the width of the ridge 4A.

Therefore, also in the second embodiment, the problem that the measurement accuracy is deteriorated due to the leakage into the groove 4B and the problem that the flow rate is reduced can be solved at the same time, and the nozzle hole 3 is formed on the surface of the non-contact type measurement head 2. , A general inexpensive measurement body can be used, and an innovative air micrometer can be obtained.

Further, the nozzle position with respect to the outer diameter of the measuring head 2 is an important point in processing that directly affects the measuring accuracy. In the case of a rectangular shape, the direction of the long side is required in addition to the center position of the nozzle. In this embodiment, the measuring head 2
The problem is solved by processing the nozzle hole 3 integrally with the nozzle hole 3 to position the processing of the nozzle hole 3 on the basis of the outer diameter, and disposing the slit-shaped nozzle hole 3 in the correct direction at the required position.

In other words, arranging the slit-shaped nozzle holes 3 in the correct position and orientation is a very important point for securing accuracy. In this embodiment, however, the finishing of the measuring head 2 has been completed. By processing the nozzle on the basis of the outer diameter, the error in the position of the nozzle hole 3 can be ignored.

In the case of the conventional round nozzle, since the hole position is determined by the forming process before finishing, the positional deviation is finally confirmed in a measurement state with air flow, and necessary correction is manually made to the nozzle hole. Although the method was modified by additional processing, in the present embodiment, the additional processing is minimized because the nozzle hole is formed at the correct position of the measuring head 2.

The present invention is not limited to the present embodiment. The width of the slit-shaped nozzle hole 3 is made sufficiently narrow with respect to the inner surface of the measurement so as to solve the problem of leakage, The direction along which the leak does not occur, that is, the direction along the inner diameter measuring portion having a certain gap with the nozzle hole 3 without at least intersecting the portion where the size of the gap and the change in air are not proportional. By setting the width and the direction so as to satisfy this condition, even if the spline or the twist groove is cut, it is possible to cope with these.

[0039]

Since the present invention is constructed as described above, a slit-shaped nozzle hole is adopted in the air micrometer for measuring the inner diameter instead of a round nozzle hole, and the orientation of the slit-shaped nozzle hole is applied to the work. By setting it in a predetermined direction, air leakage is suppressed and the change in air is not reduced by a sufficient flow rate, so that even if the length of the hole of the work is short, unevenness on the inner surface like a spline Even if it is formed, it is an epoch-making air micrometer that can measure the inner diameter with high accuracy.

That is, even if the length of the work hole is short or the unevenness is formed like the inner diameter of the spline, an inexpensive general flow type air micrometer main body can be used and the structure can be reduced. The inner diameter can be measured in a non-contact state without the need for a complicated probe such as a leaf, and it is possible to prevent the change in air and the gap size from becoming out of proportion due to air leakage. Since a sufficient air change is generated, an extremely innovative air micrometer capable of performing highly accurate inner diameter measurement with a normal measurement body without using a change expansion structure.

According to the fourth aspect of the invention, since the measurement head is finished and the nozzle hole is formed in the measurement head based on the finished outer diameter, the nozzle hole can be formed in an appropriate position and orientation. , Resulting in an extremely accurate air micrometer.

[Brief description of the drawings]

FIG. 1 is a schematic configuration explanatory view of a use state of a first embodiment.

FIG. 2 is an explanatory diagram of a main part of the first embodiment.

FIG. 3 is an enlarged explanatory sectional view of a main part in a use state of the first embodiment.

FIG. 4 is an explanatory diagram of a main part of a second embodiment.

FIG. 5 is an enlarged explanatory sectional view of a main part in a use state of the second embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Work hole 2 Measurement head 3 Nozzle hole 4 Concave and convex stripes 4A Convex stripes 4B Groove

Continued on the front page (72) Inventor Kazuyuki Suda 826-2 Tsubono, Ojiya-shi, Niigata Prefecture F-term (reference) 2F066 AA23 CC40 DD02 DD11 DD14 FF07 HH09 HH13 JJ07 KK10 MM01 MM03 MM05 MM11

Claims (4)

[Claims] 1. A nozzle hole for ejecting air is provided on the surface of a measuring head which is inserted in a non-contact state into a work hole whose inner diameter is to be measured, and a gap between the nozzle hole of the measuring head and the inner surface of the work hole is provided. In an air micrometer configured to measure the inner diameter of the work hole by converting the change in the flow rate or pressure of the air into this gap size, the nozzle hole is not a round hole, but a slit-shaped nozzle hole,
The length direction of the slit-shaped nozzle hole when the measuring head is inserted into the work hole is changed from the inner surface to be measured of the inner diameter such as the outside of the work outside the edge of the work hole or the groove on the inner surface of the hole. Air micrometer characterized by being set in a direction along an inner diameter measuring portion having a nozzle hole and a constant gap, instead of a direction intersecting with a portion where the change in the size of the gap and the change in air are not proportional due to leakage. . 2. In the nozzle hole having a short work hole and a large round hole, air leaks outside the work outside the edge of the work hole, and the size of the gap is proportional to the change in air. If the measurement accuracy deteriorates, the length direction of the slit-shaped nozzle hole when the measuring head is inserted into the work hole is set to the circumferential direction of the inner surface of the work hole. Item 2. An air micrometer according to Item 1. 3. A large round nozzle hole in which a large number of irregularities are formed on the inner surface of the work hole, air leaks into the grooves of the irregularities, and the size of the gap and the change in air are measured in proportion. When the accuracy is deteriorated, the length direction of the slit-shaped nozzle hole when the measuring head is inserted into the work hole is not set to the direction intersecting the concave and convex strips on the inner surface of the work hole, and the nozzle hole and the work hole are not inserted. The inner surface was set to a direction that coincides with the length direction of the protruding portion of the concavo-convex strip having a certain gap, and the slit width of the slit-shaped nozzle hole was set to be smaller than the width of the protruding portion. The air micrometer according to any one of claims 1 and 2, wherein: 4. The method according to claim 1, wherein after finishing the finishing of the measuring head, the slit-shaped nozzle holes are formed in a predetermined direction and at a predetermined position on the surface of the measuring head. 2. The air micrometer according to claim 1.