JP5323902B2 - Air micrometer measuring head and manufacturing method thereof - Google Patents

Description

  The present invention relates to a measurement head of an air micrometer and a manufacturing method thereof.

For workpieces that have been finished with high precision, it is required to measure their dimensions precisely. For this purpose, an air micrometer that measures the dimensions of a workpiece using air as the measurement medium. Is used.
For example, an air micrometer for measuring an inner diameter of a workpiece includes an measuring head having a measuring head inserted into a hole (measuring hole) formed in the measured object, and an outer peripheral surface of the measuring element. Air is blown from the nozzle port formed on the inner peripheral surface of the hole to be measured, and based on the change in the air flow rate or the back pressure according to the gap between the nozzle port and the inner peripheral surface of the hole to be measured, The inner diameter and the roundness are measured.

  Patent Document 1 listed below discloses an air micrometer that can simultaneously measure the inner diameter at a plurality of axial positions in a hole to be measured. FIG. 14 is an explanatory diagram schematically showing the air micrometer of Patent Document 1. The measuring head of the air micrometer includes a measuring element 117 inserted into a hole to be measured. Inside the measuring element 117, a plurality of vertical passages T1 to T3 extending along the axial direction and each vertical passage T1 are provided. A plurality of lateral passages Y1 to Y3 that are communicated with the tip of T3 and extend in the radial direction are formed. The plurality of vertical passages T <b> 1 to T <b> 3 are arranged around the axis O of the measuring element 117 at equal intervals in the circumferential direction. The plurality of lateral passages Y1 to Y3 are formed on diameter lines L1, L2, and L3 passing through the axis O of the probe 117 at positions A to C that are different from each other in the axial direction. The nozzle opening 119 is formed.

JP 2009-150780 A

As shown in FIG. 14 (a), the conventional air micrometer needs to form a plurality of longitudinal passages T1 to T3 with respect to one rod-shaped probe 117, so that complicated hole machining is required. In addition, the time and cost required for manufacturing increase. In particular, since the plurality of vertical passages T1 to T3 must be formed so as to be within a limited cross-sectional area of the measuring element 117, the processing becomes more difficult as the number increases.
Further, as shown in FIG. 14 (b), the plurality of vertical passages T1 to T3 are formed at positions eccentric from the axis O of the measuring element, respectively. The lateral passages Y1 to Y3 extending to one side and the lateral passages Y1 to Y3 extending to the other radial side have different lengths a1 and a2. For this reason, variations occur in the pressure, flow rate, and the like of the air ejected from the nozzle port 119 through the horizontal passages Y1 to Y3, which hinders highly accurate measurement.

  In general, this type of air micrometer can measure with higher accuracy as the number of nozzle ports 119 increases in each of the axial positions A to C. However, in the air micrometer shown in FIG. Since T1 to T3 are formed eccentrically from the axis O of the probe 117, only two lateral passages Y1 to Y3 are formed on one diameter line L1 to L3 at each of the axial positions A to C. And the number of nozzle ports 119 is two at the maximum. Therefore, it is practically impossible to increase the measurement accuracy by increasing the nozzle openings 119.

  An object of the present invention is to provide a measurement head of an air micrometer that can be easily manufactured and can perform highly accurate measurement, and a method of manufacturing the same.

(1) The present invention includes a plurality of vertical passages extending along the axial direction inside a probe inserted into the measurement hole, and extending along the radial direction at a plurality of axial positions of the probe. A plurality of horizontal passages communicating with each longitudinal passage and opening on the outer surface of the measuring element, and a measuring head of an air micrometer,
The probe consists of a plurality of tubes arranged concentrically and polymerized radially.
The longitudinal passage is formed between the center of the radially innermost pipe and between the pipes that overlap each other.

The measuring head of the measuring head of the present invention is composed of a plurality of tubes arranged concentrically and polymerized in the radial direction, and the vertical passage is between the center of the innermost tube in the radial direction and the tubes superposed on each other. And formed. Therefore, all the vertical passages are formed around the axis of the measuring element, and the distance to the outer surface of the measuring element is constant. Accordingly, a plurality of lateral passages extending radially outward from each longitudinal passage can be formed to have the same length, and variations in the pressure of air blown out from the plurality of transverse passages can be suppressed, and accuracy can be improved. High measurement can be performed.
In addition, the vertical passage formed between the pipes that are superposed on each other can be configured, for example, by forming a gap or a groove between the two pipes. This eliminates the need for complicated processing to form the longitudinal passage for the measuring element, making it possible to easily manufacture the measuring head.

(2) It is preferable that the vertical passage formed between two pipes that overlap each other is constituted by a groove formed on an outer peripheral surface of a pipe on the radially inner side of the two pipes.
In this way, by forming the grooves constituting the vertical passages on the outer peripheral surface of the radially inner pipe, processing is facilitated as compared to the case where the grooves are formed on the inner peripheral surface of the radially outer pipe. be able to. Therefore, it is possible to form the longitudinal passage more easily with respect to the measuring element.

(3) It is preferable that the said groove | channel is formed in the perimeter of the said pipe | tube.
With such a configuration, the flow passage area of the vertical passage can be sufficiently secured, and the horizontal passage can be communicated with the vertical passage at any position in the circumferential direction. Therefore, the degree of freedom of the position where the lateral passage is formed is increased, and an increase in the number of lateral passages can be easily handled. Further, the processing can be easily performed as compared with the case where the groove is a narrow groove extending in the axial direction.

(4) The lateral passage is formed on two or more diameter lines intersecting each other on the axis of the probe at each location in the axial direction of the probe, and in the circumferential direction on the outer surface of the probe It is preferable to open at four or more locations.
In the measuring element of the present invention, since any vertical passage is formed around the axis of the measuring element, a lateral path is formed on two or more diameter lines passing through the axis of the measuring element, and the outer surface of the measuring element is formed. It is possible to perform measurement by opening lateral passages at four or more locations in the circumferential direction and blowing air from each opening. Therefore, it is possible to perform measurement with higher accuracy.

(5) At least one lateral passage formed in the probe is formed across two pipes that overlap each other, and at least one of the opposed peripheral surfaces of the two pipes communicates with the lateral passage. It is preferable that a circumferential groove is formed.
With such a configuration, even if two pipes that overlap each other are displaced in the circumferential direction, a lateral passage can be formed across the two pipes.

(6) It is preferable that at least one pair of two pipes that overlap each other is fitted by an interference fit.
With such a configuration, it becomes possible to maintain the airtightness of the vertical passage formed between the two pipes without using a seal member, thereby reducing the number of parts, simplifying the structure, and manufacturing. Simplification can be achieved.

(7) It is preferable that two pipes fitted by interference fitting are formed of materials having different thermal expansion coefficients.
With such a configuration, the two tubes fitted by interference fit can be easily disassembled by heating or cooling. Therefore, it becomes possible to replace one of the disassembled tubes.

(8) The probe is attached to an air supply member having an attachment hole for attaching the probe and an air supply passage opened at the inner surface of the attachment hole to supply air to the vertical passage. And
It is preferable that the measuring element is fitted into the mounting hole by an interference fit.
According to this configuration, since the fitted by interference fit feeler in a mounting hole formed in the air supply member, without providing a seal member therebetween can be kept airtight, air supply Leakage of air flowing from the passage to the longitudinal passage can be prevented.

(9) It is preferable that the air supply member and the radially outermost tube constituting the measuring element are formed of materials having different thermal expansion coefficients.
With such a configuration, both the air supply member and the probe can be easily decomposed by cooling or heating. Therefore, when the probe is damaged, the probe can be removed from the air supply member and replaced with a new probe.

(10) The method of manufacturing the measurement head of the air micrometer of the present invention is as follows:
A plurality of tubes are arranged concentrically and polymerized in the radial direction to form a probe inserted into the hole to be measured,
Fit at least one set of two overlapping tubes among the plurality of tubes by an interference fit,
A vertical passage through which air flows is formed between the two pipes.
According to this configuration, since the vertical passage is formed between the two pipes fitted by interference fitting with each other, the fitting surface between the two pipes is sealed to maintain the airtightness of the vertical passage. There is no need to provide a member, the number of parts can be reduced, and the structure can be simplified and manufacturing can be facilitated.

  According to the measuring head of the air micrometer of the present invention, it is easy to manufacture and it is possible to perform highly accurate measurement.

It is a side view which shows the measuring head of the air micrometer which concerns on the 1st Embodiment of this invention. It is side surface sectional drawing of the measuring head shown by FIG. It is an expanded sectional view of the III section in FIG. It is an expanded sectional view of the IV section in FIG. It is an expanded sectional view of the V section in FIG. It is VI-VI arrow sectional drawing in FIG. It is a VII-VII arrow sectional view in FIG. It is VIII-VIII arrow sectional drawing in FIG. It is side surface sectional drawing which shows the measurement head of the air micrometer which concerns on the 2nd Embodiment of this invention. It is an expanded sectional view of the X section in FIG. It is an expanded sectional view of the XI part in FIG. It is XII-XII arrow sectional drawing in FIG. It is XIII-XIII arrow sectional drawing in FIG. It is explanatory drawing which shows a prior art schematically.

[First Embodiment]
FIG. 1 is a side view showing a measurement head 13 of an air micrometer 10 according to a first embodiment of the present invention. The air micrometer 10 includes an air supply source 11, a measurement unit 12, and a measurement head 13, and the air supply source 11 and measurement unit 12, and the measurement unit 12 and measurement head 13 are connected by an air pipe 14. Has been. Then, the air (compressed air) generated by the air supply source 11 is supplied to the measurement unit 12 and the measurement head 13 via the air pipe 14, and the flow rate change or back pressure change of the air blown out from the measurement head 13 is measured. By measuring according to 12, a predetermined dimension of the workpiece W is measured. The air micrometer 10 of the present embodiment is used to measure the inner diameter, roundness, etc. of a hole (measurement hole) Wh formed in the measurement object W.

<Configuration of measuring head 13>
The measurement head 13 is inserted into the body portion 16 that receives air supply from the air supply source 11 and the measurement hole Wh of the object W to be measured, and also blows out air toward the inner peripheral surface of the measurement hole Wh. And a child 17. The main body 16 is formed in a substantially cylindrical shape centered on the axis O, and three joints (first to third joints) J1 to J3 to which the air pipe 14 is connected are attached to the outer peripheral surface. It has been. Therefore, air is supplied to the main body portion 16 in three systems. Further, first to third air supply passages R <b> 1 to R <b> 3 (see FIG. 2) for supplying air to the probe 17 are formed inside the main body portion 16.

  The measuring element 17 is provided concentrically with the main body 16 and protrudes from one end surface of the main body 16 in the axial direction. The measuring element 17 is formed in a substantially cylindrical shape, and a nozzle port 19 for blowing air is formed on the outer peripheral surface thereof. In the probe 17 of the present embodiment, a plurality of nozzle openings 19 are formed at three locations (first to third axial positions) A to C that are separated in the axial direction. At C, the dimension of the hole Wh to be measured can be measured simultaneously.

FIG. 2 is a side sectional view of the measuring head 13 shown in FIG.
Inside the probe 17 of the measuring head 13, a plurality of longitudinal passages T1 to T3 extending along the axis O, and a plurality of transverse passages Y1 to Y3 communicating with the longitudinal passages T1 to T3 and extending in the radial direction are provided. Is formed. Three vertical passages T1 to T3 are formed so as to correspond to the first to third air supply passages R1 to R3 of the three systems. Hereinafter, these three longitudinal passages T1 to T3 are referred to as a first longitudinal passage T1, a second longitudinal passage T2, and a third longitudinal passage T3, respectively. Further, the lateral passages Y1 to Y3 are formed at first to third axial positions A to C. Each of the lateral passages Y1 to Y3 is opened on the outer peripheral surface of the measuring element 17, and this opening is the nozzle port 19 described above. Further, the horizontal passages Y1 to Y3 at the respective axial positions A to C are communicated with the first to third vertical passages T1 to T3, respectively.

<Structure of probe 17>
The probe 17 is composed of a plurality of tubes arranged concentrically and polymerized in the radial direction. Specifically, the probe 17 of the present embodiment is composed of three pipes P1 to P3. In the following description, the three tubes are referred to as a first tube P1, a second tube P2, and a third tube P3 from the radially inner side.
The first pipe P <b> 1 has an axial length over the entire length of the measuring head 13. A first vertical passage T1 is formed at the center of the first pipe P1. The distal end portion (right end portion in FIG. 2) and the base end portion (left end portion in FIG. 2) of the first vertical passage T1 are closed by a sealing plug 22, and air leakage from the end portion is prevented.

A small diameter portion 24 having a small outer diameter is formed in a range of about 2/3 of the first end of the first pipe P1. A large-diameter portion 26 having a large outer diameter is formed on the distal end side of the small-diameter portion 24 via a step portion 25. The second pipe P2 is attached to the small diameter part 24 of the first pipe P1 by fitting.
The second pipe P2 has an inner diameter slightly smaller than the outer diameter of the small diameter part 24 in the first pipe P1 and an outer diameter substantially the same as the outer diameter of the large diameter part 26. Moreover, the 2nd pipe | tube P2 is formed in the axial direction length substantially the same as the small diameter part 24 in the 1st pipe | tube P1.

  And this 2nd pipe | tube P2 is fitted by the interference fit with respect to the small diameter part 24 of the 1st pipe | tube P1. That is, with the second tube P2 thermally expanded or the first tube P1 thermally contracted, the small-diameter portion 24 of the first tube P1 is inserted into the second tube P2 so as to reach room temperature. By returning, both are fitted with a margin. Accordingly, the first pipe P1 and the second pipe P2 are in close contact with each other except a passage forming groove 38 described later, and airtightness is maintained.

  The third pipe P <b> 3 arranged on the outermost side in the radial direction of the probe 17 is formed integrally with the main body portion 16. Then, the first pipe P1 and the second pipe P2 integrated by fitting are fitted in the cylinder of the third pipe P3 and the attachment hole 29 formed in the main body portion 16. Specifically, the first pipe P1 and the second pipe P2 are fitted into the third pipe P3 and the attachment hole 29 of the main body portion 16 by a clearance fit or an intermediate fit. Between the first pipe P1 and the second pipe P2, and the third pipe P3 and the mounting hole 29, airtightness is maintained by a seal member 30 such as an O-ring provided at an appropriate position in the axial direction. . It should be noted that the first probe P1 and the third pipe P3 overlap each other in the radial direction in the first axial position A on the distal end side of the measuring element 17, and the second and third axial directions. In the positions B and C, the first pipe P1 and the second pipe P2, and the second pipe P2 and the third pipe P3 are respectively superposed in the radial direction.

<Configuration of first vertical passage and first horizontal passage>
As shown in FIG. 2, the first longitudinal passage T1 formed in the center of the first pipe P1 has an axial length extending from at least the first air supply passage R1 to the first axial position A. doing. The base end side (left end side) of the first vertical passage T1 is communicated with the first air supply passage R1 through a communication passage 31 formed in the radial direction in the first pipe P1 and the second pipe P2. ing.

  A first lateral passage Y1 that extends in the radial direction and communicates with the first longitudinal passage T1 is formed at a first axial position A of the probe 17. As shown in FIGS. 3 and 6, the first lateral passage Y <b> 1 is formed along diameter lines L <b> 1 and L <b> 2 that pass through the axis O of the probe 17. In the measuring element 17 of the present embodiment, four first lateral passages Y1 extending radially outward from the first longitudinal passage T1 are formed along two diameter lines L1 and L2 orthogonal to each other. ing. In addition, since the first vertical passage T1 is formed around the axis O of the probe 17, the four first horizontal passages Y1 extending radially outward from the first vertical passage T1 are: They are formed to have the same length.

  Each first lateral passage Y1 includes an inner diameter portion Y1a formed in the first tube P1 and an outer diameter portion Y1b formed in the third tube P3. 3 pipes P3. The inner diameter portion Y1a in the first lateral passage Y1 is formed to have a slightly larger diameter than the outer diameter portion Y1b. Further, a circumferential groove 34 that is wider in the axial direction than the radially inner portion Y1a is formed on the entire outer peripheral surface of the first pipe P1. By this circumferential groove 34, the inner diameter portion Y1a and the outer diameter portion Y1b in the first lateral passage Y1 are communicated with each other. If such a circumferential groove 34 is not formed, it is required that the radially inner portion Y1a and the radially outer portion Y1b be strictly aligned both in the axial direction and in the circumferential direction. In this way, even if the inner diameter portion Y1a and the outer diameter portion Y1b are slightly displaced in the axial direction or the circumferential direction, the two portions Y1a, Y1b can be communicated with each other.

  The first lateral passage Y1 opens at the outer peripheral surface of the third pipe P3, and this opening is a nozzle port 19. In the present embodiment, since the four first lateral passages Y1 are formed on the two diameter lines L1 and L2 orthogonal to each other, at the first axial position A, the third pipe P3 A total of four nozzle openings 19 are formed at 90 ° intervals on the outer peripheral surface. As shown in FIG. 2, the air supplied from the first joint J1 to the first vertical passage T1 through the first air supply passage R1 and the communication passage 31 is composed of four first lateral passages. It is discharged from the four nozzle openings 19 through Y1, and sprayed onto the inner peripheral surface of the hole to be measured Wh. The distance from the nozzle port 19 to the inner peripheral surface of the hole to be measured Wh is set to several tens of μm.

  As shown in FIG. 6, an annular groove 36 is formed around the nozzle opening 19. A long groove 37 is formed on one side of the annular groove 36 so as to overlap. As shown in FIG. 1, the long groove 37 extends in the axial direction over most of the longitudinal direction of the third pipe P3. The annular groove 36 and the long groove 37 are for releasing the air blown from the nozzle port 19 to the outside of the hole to be measured Wh. Further, as shown in FIG. 3, seal members 30 made of O-rings are provided on both sides in the axial direction of the first lateral passage Y1, and air leakage from between the radially inner portion Y1a and the radially outer portion Y1b. Is prevented.

<Configuration of second vertical passage and second horizontal passage>
As shown in FIG. 2, a passage forming groove 38 for forming a second vertical passage T2 is formed on the outer peripheral surface of the small diameter portion 24 in the first pipe P1. The passage forming groove 38 has an axial length extending between the second air supply passage R2 and the second axial position B, and is formed on the entire circumference of the small diameter portion 24 of the first pipe P1. Is formed. Then, by superposing the small diameter portion 24 of the first pipe P1 and the second pipe P2, the second vertical passage T2 surrounded by the passage forming groove 38 and the inner peripheral surface of the second pipe P2 is formed. It is formed. Accordingly, the second vertical passage T2 is a cylindrical passage (see FIG. 7) formed between the first pipe P1 and the second pipe P2 with the axis O of the probe 17 as the center. ing. The base end side (left end side) of the second vertical passage T2 communicates with the second air supply passage R2 via a communication passage 39 formed in the second pipe P2.

  A second lateral passage Y2 that extends in the radial direction and communicates with the second longitudinal passage T2 is formed at the second axial position B of the probe 17. As shown in FIGS. 4 and 7, the second lateral passage Y <b> 2 is formed along diameter lines L <b> 1 and L <b> 2 that pass through the axis O of the probe 17. In the present embodiment, four second transverse passages Y2 extending radially outward from the second longitudinal passage T2 are formed along two diameter lines L1, L2 orthogonal to each other. Further, since the second vertical passage T2 is formed around the axis O of the probe 17, the four second horizontal passages Y2 extending radially outward from the second vertical passage T2 are: They are formed to have the same length.

  Each second lateral passage Y2 includes an inner diameter portion Y2a formed in the second tube P2 and an outer diameter portion Y2b formed in the third tube P3. The second tube P2 and the third tube It is formed straddling the pipe P3. The inner diameter portion Y2a in the second lateral passage Y2 is formed to have a slightly larger diameter than the outer diameter portion Y2b. Further, a circumferential groove 42 that is wider in the axial direction than the radially inner portion Y2a is formed on the entire outer peripheral surface of the second pipe P2. By the circumferential groove 42, the inner diameter portion Y2a and the outer diameter portion Y2b in the second lateral passage Y2 are communicated with each other. Moreover, even if the radially inner portion Y2a and the radially outer portion Y2b are slightly displaced in the axial direction or the circumferential direction by the circumferential groove 42, both the portions Y2a and Y2b can be communicated with each other.

The second lateral passage Y <b> 2 opens at the outer peripheral surface of the third pipe P <b> 3, and this opening is a nozzle port 19. In the present embodiment, since the four second lateral passages Y2 are formed on the two diameter lines L1 and L2 orthogonal to each other, at the second axial position B, the third pipe P3 A total of four nozzle openings 19 are formed at 90 ° intervals on the outer peripheral surface. As shown in FIG. 2, the air supplied from the second joint J2 to the second vertical passage T2 via the second air supply passage R2 and the communication passage 39 is composed of four second lateral passages. It is discharged from the four nozzle openings 19 through Y2, and sprayed to the inner peripheral surface of the hole to be measured Wh.

<Configuration of third vertical passage and third horizontal passage>
As shown in FIG. 2, a passage forming groove 44 for forming a third vertical passage T3 is formed on the outer peripheral surface of the second pipe P2. The passage forming groove 44 has an axial length extending between the third air supply passage R3 and the third axial position C, and is formed on the entire circumference of the second pipe P2. . Then, by superposing the second pipe P2 and the third pipe P3, the first pipe surrounded by the passage forming groove 44 and the inner peripheral surface of the third pipe P3 (and the inner peripheral surface of the mounting hole 29). 3 vertical passages T3 are formed. Therefore, the third vertical passage T3 is a cylindrical passage (see FIG. 8) formed between the second pipe P2 and the third pipe P3 with the axis O of the probe 17 as the center. Yes. Further, the base end side (left end side) of the third vertical passage T3 communicates with the third air supply passage R3.

  A third lateral passage Y3 that extends in the radial direction and communicates with the third longitudinal passage T3 is formed at a third axial position C of the probe 17. As shown in FIGS. 5 and 8, the third lateral passage Y <b> 3 is formed along diameter lines L <b> 1 and L <b> 2 that pass through the axis O of the probe 17. In the present embodiment, four third lateral passages Y3 extending outward in the radial direction from the third longitudinal passage T3 are formed along two diameter lines L1 and L2 orthogonal to each other. Further, since the third vertical passage T3 is formed around the axis O of the measuring element 17, the four third horizontal passages Y3 extending radially outward from the third vertical passage T3 are: The same length is formed.

The third lateral passage Y3 is formed with respect to the third pipe P3 and opens on the outer peripheral surface of the third pipe P3. In the present embodiment, since the four third lateral passages Y3 are formed on the two diameter lines L1 and L2 orthogonal to each other, at the third axial position C, the third pipe P3 A total of four nozzle openings 19 are formed at 90 ° intervals on the outer peripheral surface. As shown in FIG. 2, the air supplied from the third joint J3 to the third vertical passage T3 via the third air supply passage R3 passes through the third horizontal passage Y3 and is connected to the nozzle port 19. And is sprayed onto the inner peripheral surface of the hole to be measured Wh.

  The air micrometer 10 having the above configuration is configured by the measuring element 17 concentrically and radially superposing the first to third tubes P1 to P3, and the center of the first tube P1 and the first A plurality of vertical passages T1 to T3 are formed between the first to third pipes P1 to P3. Therefore, each of the plurality of vertical passages T1 to T3 is formed around the axis O of the probe 17, and the distance from each of the vertical passages T1 to T3 to the outer peripheral surface of the probe 17 is set at any position in the circumferential direction. Can be constant. Accordingly, at each of the axial positions A to C, a plurality of horizontal passages Y1 to Y3 extending radially outward from the vertical passages T1 to T3 can be formed to have the same length. It is possible to prevent variations in the pressure of the air blown to the measurement hole Wh through the plurality of lateral passages Y1 to Y3, and to realize highly accurate measurement.

  Further, when a plurality of vertical passages are formed side by side with respect to the measuring element 17 made of one rod-like member as in the prior art, very complicated hole machining is required. However, the measuring element of this embodiment By vertically polymerizing the plurality of pipes P <b> 1 to P <b> 3 as shown in FIG. 17, a vertical passage can be formed using the gaps (grooves) between the pipes P <b> 1 to P <b> 3. Therefore, a plurality of vertical passages can be easily formed for the measuring element 17.

  Further, the passage forming groove 38 forming the second vertical passage T2 is formed on the outer peripheral surface of the first pipe P1 located on the radially inner side of the first pipe P1 and the second pipe P2 that overlap each other. Has been. On the contrary, the passage forming groove 38 can be formed on the inner peripheral surface of the second pipe P2 located on the radially outer side, but in this case, the processing on the inner peripheral surface of the pipe P2 Therefore, work becomes difficult. Therefore, the second vertical passage T2 can be easily formed by forming the passage forming groove 38 on the outer peripheral surface of the first pipe P1 on the radially inner side.

  Similarly, the passage forming groove 44 constituting the third vertical passage T3 is formed on the outer peripheral surface of the second pipe P2 located on the radially inner side of the second pipe P2 and the third pipe P3 that overlap each other. Since it is formed, the processing of the passage forming groove 44 is facilitated, and the third vertical passage T3 can be easily formed.

Further, since the second and third vertical passages T2 and T3 are formed all around the axis O of the probe 17, the lateral passage Y2 extending radially outward from any position in the circumferential direction. , Y3 can be formed. Therefore, the degree of freedom of the position where the horizontal passages Y2 and Y3 are formed is increased, and it is possible to easily cope with the case where the number of the horizontal passages Y2 and Y3 is increased.

Further, since the first pipe P1 and the second pipe P2 are closely fitted by an interference fit, the seal member 30 is not necessary between them. Therefore, the number of parts can be reduced, and the structure of the measuring element 17 can be simplified and the manufacture thereof can be facilitated.
Here, the materials of the first pipe P1 and the second pipe P2 that are fitted by interference fitting will be described.

The material of the 1st pipe | tube P1 can be formed from the single member (sintered body) etc. which were formed by sintering. For example, the material of the first pipe P1 can be general wear-resistant cemented carbide (V10, V20, V30) or ceramics (alumina, zirconia). In the case of cemented carbide, its thermal expansion coefficient is 5-6 × 10 ⁻⁶ / ° C., alumina is 8 × 10 ⁻⁶ / ° C., and zirconia is 10.4 × 10 ⁻⁶ / ° C.

On the other hand, the material of the second pipe P2 is, for example, austenitic stainless steel (SUS303, SUS304), alloy tool steel (SKS3, SKD11), or high-speed tool steel. In the case of SUS303, the thermal expansion coefficient is 17.2 × 10 ⁻⁶ / ° C., SUS304 is 17.3 × 10 ⁻⁶ / ° C., SKS3 is 14 × 10 ⁻⁶ / ° C., and SKD11 is 12 2 × 10 ⁻⁶ / ° C. Thus, the 2nd pipe | tube P2 consists of a material with a larger thermal expansion coefficient than the 1st pipe | tube P1. In addition, each value of a thermal expansion coefficient is a case of 1-100 degreeC.

  Therefore, when fitting the first pipe P1 and the second pipe P2 by interference fitting, the first pipe P1 is placed inside the second pipe P2 by heating and expanding the second pipe P2. It can be attached. The first pipe P1 and the second pipe P2 can be disassembled. That is, by heating the integrated first pipe P1 and second pipe P2, the second pipe P2 expands more than the first pipe P1, and thus both pipes can be easily disassembled. Can do. Therefore, it is possible to replace either the first pipe P1 or the second pipe P2.

  Note that the first pipe P1 and the second pipe P2 may be formed of the same material. However, in this case, when disassembling the first pipe P1 and the second pipe P2, it is difficult to make a difference in thermal expansion between them, so that the first pipe P1 and the second pipe P2 are formed of materials having different thermal expansion coefficients. Is preferred. The material of the third pipe P3 is not particularly limited, and the same material as the second pipe P2 (for example, tool steel (SKS3, SKD11, etc.)) may be used.

[Second Embodiment]
FIG. 9 is a side sectional view showing the measurement head 13 of the air micrometer 10 according to the second embodiment of the present invention.
The measuring head 13 according to the present embodiment includes two pipes (a first pipe P1 and a second pipe P2) in which a measuring element 17 is concentrically arranged and polymerized in a radial direction. In addition, nozzle openings 19 are formed on the outer peripheral surface of the probe 17 at two locations in the axial direction (first axial position A and second axial position B). Furthermore, the measuring element 17 is formed separately from the main body part 16, and the measuring element 17 is attached to an attachment hole 29 formed in the main body part 16. Therefore, in the present embodiment, the measuring head 13 is substantially constituted by the measuring element 17, and this measuring element 17 is attached to the main body (air supply member) 16 having the air supply passages R1, R2. It will be explained as a thing.

Joints J1 and J2 to which the air pipe 14 is connected are attached to the main body portion 16, and air supply passages R1 and R2 communicating with the joints J1 and J2 are formed.
The measuring element 17 includes a first pipe P1 and a second pipe P2 fitted to the outer periphery of the first pipe P1. A first vertical passage T1 is formed at the center of the first pipe P1, and a second vertical passage T2 is formed between the first pipe P1 and the second pipe P2. Further, lateral passages Y1 and Y2 and a nozzle port 19 are formed at the first axial position A and the second axial position B, respectively.

  The first pipe P1 and the second pipe P2 are fitted by a clearance fit or an intermediate fit. And the sealing member 46 which consists of an O-ring is provided in the appropriate location of the axial direction between both. Further, the distal end side and the proximal end side of the first vertical passage T1 formed in the first pipe P1 are closed by a sealing plug 22. The base end side of the first vertical passage T1 is communicated with the first air supply passage R1 through the communication passage 31.

  As shown in FIGS. 10 and 12, the first lateral passage Y <b> 1 is formed on two diameter lines L <b> 1 and L <b> 2 that pass through the axis O of the probe 17 and are orthogonal to each other. Accordingly, four first lateral passages Y1 extending radially outward from the first longitudinal passage T1 are formed, and the first lateral passage Y1 is opened by opening at the outer peripheral surface of the second pipe P2. The nozzle openings 19 are formed at 90 ° intervals. The four first lateral passages Y1 are formed to have the same length.

  The first lateral passage Y1 includes an inner diameter portion Y1a formed in the first tube P1 and an outer diameter portion Y1b formed in the second tube P2, and the first tube P1 and the second tube Y1. It is formed across the tube P2. In addition, a circumferential groove 34 is formed on the outer peripheral surface of the first pipe P1, and the radially inner portion Y1a and the radially outer portion Y1b communicate with each other. A plurality of long grooves 37 are formed on the outer peripheral surface of the second pipe P2.

As shown in FIG. 9, a passage forming groove 38 for forming the second vertical passage T2 is formed on the outer peripheral surface of the first pipe P1. The passage forming groove 38 has an axial length extending between the second air supply passage R2 and the second axial position B, and is formed on the entire circumference of the outer peripheral surface of the first pipe P1. ing. Then, by polymerizing the first tube P1 and the second tube P2, a second longitudinal channel T2 enclosed between the passage forming grooves 38 inner peripheral surface of the second tube P 2 is formed Is done. Therefore, the second vertical passage T2 is a cylindrical passage (see FIG. 13) formed between the first pipe P1 and the second pipe P2 with the axis O of the probe 17 as the center. ing.

  As shown in FIGS. 11 and 13, the second lateral passage Y <b> 2 is formed on two diameter lines L <b> 1 and L <b> 2 that pass through the axis O of the probe 17 and are orthogonal to each other. Accordingly, four second lateral passages Y2 extending radially outward from the second longitudinal passage T2 are formed, and the second lateral passages Y2 are opened by opening at the outer peripheral surface of the second pipe P2. The nozzle openings 19 are formed at 90 ° intervals. Further, the second lateral passage Y2 is formed only in the second pipe P2. The four second lateral passages Y2 are formed to have the same length.

  As described above, the second pipe P <b> 2 of the probe 17 is fitted into the attachment hole 29 of the main body portion 16 by an interference fit. That is, as shown in FIG. 9, with the main body portion 16 thermally expanded or the second tube P2 thermally contracted, the second tube P2 is inserted into the mounting hole 29 of the main body portion 16, By returning to normal temperature, both are fitted with a margin. Therefore, the main body portion 16 and the measuring element 17 are in close contact with each other without any gap and airtightness is maintained. Therefore, it is not necessary to provide a seal member between the mounting hole 29 of the main body portion 16 and the second pipe P2, the number of parts can be reduced, and the structure can be simplified and the manufacturing can be facilitated. it can.

  Further, it is desirable that the main body portion 16 and the second pipe P2 are formed of materials having different thermal expansion coefficients. The 2nd pipe | tube P2 can be formed from the cemented carbide for general body wear, ceramics, etc. which were mentioned above, for example. The main body 16 can be formed of a material having a larger thermal expansion coefficient than the second pipe P2, for example, stainless steel, alloy tool steel, high-speed tool steel, or the like as described above. And when disassembling the main-body part 16 and the measuring element 17, the measuring element 17 can be easily removed by heating the main-body part 16 and carrying out thermal expansion. Therefore, when the probe 17 is damaged by use, the probe 17 can be easily replaced. Other functions and effects in the second embodiment are substantially the same as those in the first embodiment.

The present invention is not limited to the above-described embodiment, and can be appropriately changed within the scope of the invention described in the claims.
For example, the number of lateral passages and the number of nozzle openings at each of the axial positions A to C of the probe 17 are not limited to four, and can be formed more or less than this. For example, through the axis O of the measuring element 17, it is possible to form the eyelet on the three or more diameters lines crossing at equal angles to each other. In this case, the number of lateral passages is 6 or more, and the number of nozzle openings 19 is 6 or more, so that it is possible to perform more accurate measurement.

  Further, the measuring element 17 is not limited to the measurement at the three axial positions (the first embodiment) or the two positions (the second embodiment) at the same time, and is simultaneously measured at four or more axial positions. It may be what performs. In this case, the number of tubes corresponding to the number of measurement points may be polymerized in the radial direction.

In the first and second embodiments described above, the longitudinal passage formed between the two pipes polymerized in the radial direction is a passage forming groove formed on the entire circumference of the peripheral surface of at least one of the pipes. However, the passage forming groove can be constituted by a plurality of narrow grooves in the circumferential direction, for example.
In the probe 17 shown in FIG. 2, the second pipe P2 may be formed to have a length equivalent to that of the first pipe P1, and the first pipe P1 is also formed on the distal end side of the probe 17. And it may be polymerized in the radial direction with the third pipe P3.

10: Air micrometer 13: Measuring head 16: Main body (air supply member)
17: Measuring element 19: Nozzle port 29: Mounting hole 34: Circumferential groove 38: Passage forming groove 42: Circumferential groove 44: Passage forming groove P1: First pipe P2: Second pipe P3: Third pipe T1: First vertical passage T2: Second vertical passage T3: Third vertical passage Y1: First horizontal passage Y2: Second horizontal passage Y3: Third horizontal passage

Claims (10)

A plurality of vertical passages extending along the axial direction inside the measuring element inserted into the hole to be measured, and extending along the radial direction at a plurality of axial positions of the measuring element and communicating with the respective vertical passages, And a plurality of lateral passages opened on the outer surface of the probe, and a measurement head of an air micrometer,
The probe consists of a plurality of tubes arranged concentrically and polymerized radially.
The measuring head of an air micrometer, wherein the longitudinal passage is formed between the center of the radially innermost tube and the tube overlapping each other.   2. The air micrometer according to claim 1, wherein the longitudinal passage formed between two pipes that overlap each other is formed by a groove formed on an outer peripheral surface of a pipe on the radially inner side of the two pipes. Measuring head.   The measurement head of the air micrometer according to claim 2, wherein the groove is formed on the entire circumference of the tube.   The lateral passages are formed on two or more diameter lines intersecting each other on the axis of the measuring element at each position in the axial direction of the measuring element, and four or more in the circumferential direction on the outer surface of the measuring element. The measurement head of the air micrometer according to any one of claims 1 to 3, wherein the measurement head is open at a point.   At least one of the lateral passages is formed across two pipes that overlap each other, and at least one of the opposed peripheral surfaces of the two pipes is formed with a circumferential groove communicating with the lateral passage. The measurement head of the air micrometer according to claim 1.   The measuring head of an air micrometer according to any one of claims 1 to 5, wherein at least one pair of two tubes that overlap each other is fitted by an interference fit.   The measuring head of an air micrometer according to claim 6, wherein the two pipes fitted by interference fitting are formed of materials having different coefficients of thermal expansion. The probe is attached to an air supply member having an attachment hole for attaching the probe and an air supply passage opened at an inner surface of the attachment hole to supply air to the vertical passage,
The measurement head of the air micrometer according to claim 1, wherein the measuring element is fitted into the mounting hole by an interference fit.   The measurement head of an air micrometer according to claim 8, wherein the air supply member and the radially outermost tube constituting the measuring element are formed of materials having different thermal expansion coefficients. A measuring element inserted into the hole to be measured is formed by concentrically arranging a plurality of tubes and polymerizing in a radial direction,
Fit at least one set of two overlapping tubes among the plurality of tubes by an interference fit,
A method of manufacturing a measuring head for an air micrometer, characterized in that a longitudinal passage for allowing air to flow between the two tubes is formed.

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