JPH01142408A - Plug gage for flow rate type air micrometer and manufacture thereof - Google Patents

Abstract

PURPOSE:To set a minor axis as small as possible, by providing the nozzle hole of an air nozzle in the shape of a long slender one in the circumferential direction of the main body of a plug gage. CONSTITUTION:A nozzle hole 9 of an air nozzle 2 is made to be a long slender one in the circumferential direction of a main body 1 of a plug gage. The minor axis of the diameter of the hole is set as small as possible. An annular product, which has a narrow width in the axial direction, a blind hole, which has a shallow depth in the axial direction, and the like can be measured. Meanwhile, a major axis is set so that the cross section of the nozzle hole 9 has a size in order to secure a specified back pressure or more. Thus, the annular product, which has the narrow width in the axial direction, the blind hole, which has the shallow depth in the axial direction, and the like, can be measured accurately, which cannot be measured with a conventional plug gage so far. The minor axis, i.e., the diameter in the axial direction, can be made as small as possible without a booster.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to a plug gauge for a flow rate air micrometer used to measure various dimensions such as the inner diameter of an annular field, the roundness of the inner diameter, or the degree of gradient. and its manufacturing method.

(Prior Art) In general, a flow rate air micrometer as shown in Fig. 10 is generally used to measure the inner diameter dimension, roundness or gradient of the inner diameter of an annular field such as the inner ring of a bearing. ing.

The air micrometer is equipped with a plug gauge A as its measuring point, and the plug gauge A is connected to a measuring section (not shown) consisting of a tapered tube and a float installed in the indicating section main body through a pipe a. The main body of the indicating section has a function of displaying the dimensions of the object to be measured from the measurement results of the measuring section.

In addition, a conventional plug gauge, for example, a plug gauge for measuring a circular ring such as an inner ring of a bearing, has a plug gauge main body d having a cylindrical outer circumferential surface at its tip end, as shown in FIGS. 11 and 12. A pair of air nozzles e, e are provided facing the outer peripheral surface, and the air nozzles e, e are connected to the connecting base end g via an air passage f provided along the axial center of the plug gauge main body d. This is connected to the pipe a.

The air nozzle e is formed by drilling with a drilling machine or the like after manufacturing the plug gauge main body d, so the shape of the nozzle hole is circular (so-called round hole) as shown in FIG. 13.

For example, when measuring the inner diameter dimension of the inner ring W of a bearing as shown in FIG. Spray on the surface. Then, back pressure is generated on the float in the tapered tube installed in the indicator main body, causing the float to float, and the inner diameter of the inner ring W can be measured by reading the display of the float position.

(Problems to be solved by the invention) However, in the structure of plug gauge A like this,
There were the following problems.

That is, the measurement range by the air micrometer is determined by the shape and dimensions of the plug gauge A.

In particular, the minimum range of the axial width of the object to be measured is determined by the hole diameter of the air nozzles e, e, but this hole diameter cannot be made so small because it is necessary to ensure a back pressure of a certain pressure or more. For this reason, the conventional round hole (circular hole)
With this method, it is not possible to measure objects with a narrow axial width or blind holes with a shallow axial depth.

For example, when measuring the inner ring W of the bearing, it is necessary to completely cover the inner diameter surface of the inner ring W with the nozzle holes of the air nozzles e, e, but the nozzle hole diameter of the air nozzles is the smallest one. .0 crane size, and inner circle W
Since the covering cost is at least 0.5 cranes, the inner ring W
The minimum axial width is required to be at least 7 fins, and if it is less than this, the measurement accuracy will be extremely reduced.

Therefore, dial gauges and cylinder gauges are generally used to measure objects with narrow axial widths, blind holes with shallow axial depths, etc. that cannot be measured with an air micrometer.

However, with dial gauges and cylinder gauges, measurement errors are likely to occur for the following reasons, and high precision measurement cannot be expected, and measurement work is difficult.

In other words, with these measuring instruments, it is necessary to bring the probe into contact with the measuring surface of the object to be measured at a right angle, but achieving this right angle requires skill, making the work difficult and causing errors. tends to occur.

In addition, there is a measurement pressure in the contact of the probe (for example, a force of 50 to 150 gf is applied for a dial gauge, and 150 to 510 gf is applied in a measurement range of 50 to 100 dragons for a cylinder gauge), and in the case of a thin ring, Its shape will be deformed, which will cause errors in the measured values.

Furthermore, if dust or the like adheres to the contact surface of the probe, measurement errors will occur due to this.

(Means for Solving the Problems) The present invention has been made in view of such conventional problems, and the first invention of the present invention, which is a plug gauge for an air micrometer, has the following features: An air passage is provided inside a plug gauge body having an outer circumferential surface corresponding to the circumferential surface, and a pair of air nozzles communicating with the air passage are provided facing the outer circumferential surface,
In the second aspect of the present invention, the air nozzle is formed separately from the plug gauge main body, and the nozzle hole is an elongated hole extending in the circumferential direction of the plug gauge main body. A method of manufacturing a plug gauge for an air micrometer involves forming an outer circumferential surface corresponding to the inner circumferential surface of an object to be measured, and forming an air passageway in the internal axial direction of the plug gauge body, which is connected to the air passageway. A pair of communicating nozzle mounting holes are formed, and a pair of air nozzles each having an elongated nozzle hole are manufactured separately from the plug gauge body, and the pair of air nozzles are inserted into the nozzle mounting holes of the plug gauge body. is characterized in that it is mounted and fixed such that the major diameter direction of the nozzle hole coincides with the circumferential direction of the plug gauge main body.

(Function) According to the first invention, the nozzle hole of the air nozzle is an elongated hole in the circumferential direction of the plug gauge main body, and the diameter of the hole is such that the short diameter is set as small as possible and While it is possible to measure annular products with a narrow width in the direction or blind holes with a shallow depth in the axial direction, it is possible to measure the long diameter so that the cross-sectional area of the nozzle hole is large enough to ensure a back pressure of at least a certain pressure. is set to

That is, the nozzle hole is designed based on the following theory.

In Fig. 9, when air at a constant pressure is released into the atmosphere from the nozzle hole B (hole diameter d) of the plug gauge, the outflow amount V is determined by the cross-sectional area π (d/2) of the nozzle hole B from the following formula. Proportional to 2.

v=pρπ(d/2)2 ρ: Flow coefficient P: Air pressure (constant) On the other hand, if the nozzle hole B is close to the object C to be measured and is at a distance, the flow rate V will flow along the object C to be measured. It is proportional to the cross-sectional area πdh when blowing out to the surroundings.

Furthermore, the air nozzle is formed separately from the plug gauge body, making it easy to form an elongated nozzle hole.

According to the second aspect of the present invention, the plug gauge body has an outer circumferential surface corresponding to the inner circumferential surface of the object to be measured and an air passage formed in the internal axial direction, and a pair of nozzles communicating with the air passage. A pair of air nozzles each having a mounting hole and an elongated nozzle hole are manufactured separately from the plug gauge body, and then the air nozzle is inserted into the nozzle mounting hole of the plug gauge body. Install and fix so that the long diameter direction matches the circumferential direction of the plug gauge body. As a result, the nozzle hole of the air nozzle that satisfies the above conditions can be easily and accurately formed.

(Example) Embodiments of the present invention will be described below based on the drawings.

A plug gauge for a flow rate air micrometer according to the present invention is shown in FIGS. 1 and 2, and specifically, the plug gauge is as shown in FIGS. This device is for measuring various dimensions of an annular object W to be measured, and has a pair of air nozzles 2.2 embedded integrally in the plug gauge main body 1, and has a flow rate type shown in FIG. Used as measuring point A of an air micrometer.

The plug gauge main body 1 is made of SUJ 2 and is hardened, and includes a guide portion 5 having a cylindrical outer circumferential surface 4 corresponding to the inner circumferential surface 3 of the object W to be measured, and a guide portion 5 at the rear end of the guide portion 5. It consists of a connecting part 6 integrally formed on the same axis. Inside the plug gauge body 1, an air passage 7 is provided extending along the axial center of the plug gauge body 1 from the axial center of the guide portion 5 to the rear end of the connecting portion 6. The pipe a of the air micrometer is connected thereto. Further, an air passage 8 extending in one diameter direction of the guide portion 5 is communicated with the tip end of the air passage 7, and an outer circular end of the air passage 8 is communicated with the air nozzle 2.2.

The air nozzle 2 is made of S 45 C@ and is hardened, and is formed separately from the plug gauge body 1 and buried so as to face the outer peripheral surface 4 of the plug gauge body 1. The nozzle hole 9 of the air nozzle 2 is an elongated hole elongated in the circumferential direction of the outer peripheral surface 4 of the plug gauge main body 1. As shown in FIG. 3, the shape and dimensions of the nozzle hole 9 are set such that the major axis is, for example, 1.5 to 3.0 mm.

Note that the buried position of the air nozzle 2 is set in accordance with the shape and dimensions of the object to be measured W, and for example, a narrow, thin type circular ring as shown in FIG. The inner diameter of
When measuring the presence or absence of the edge) 10, the central part in the axial direction of the guide part 5 is measured as shown in FIG.
When measuring a shallow inner diameter such as the inner diameter of the outer ring seal as shown in Figure (C) or the inner diameter of a blind hole as shown in Figure 4(d), the axial tip of the guide portion 5 is used. (not shown).

Further, an air escape groove 9a is provided in the outer peripheral portion of the nozzle hole 9.
is formed, and the air escape groove 9a is further formed in the guide portion 5.
It is connected to an axial air escape groove 11 formed on the outer circumferential surface 4 of.

Next, a method of manufacturing the above plug gauge will be explained.

A. Boo gauge 1 (see Figures 5 and 6): ■ The outer circumferential surface 4 of the plug gauge body 1 is turned with a cutting tool using a lathe to form a cylindrical shape corresponding to the inner circumferential surface 3 of the object W to be measured. do.

■ Open an air passage 7 along the axial center of the plug gauge body 1.

(2) An air passage 8 communicating with the air passage 7 is formed on the outer peripheral surface 4 of the plug gauge main body 1.

■ Counterbore the nozzle mounting hole 12 concentrically with the air passage 8 using a drill.

■ Machining the air escape groove 11 in the axial direction.

■ Harden the plug gauge body 1.

B. Air nozzle (see Figures 7 and 8): ■ Turn the outer peripheral surface 2a of the air nozzle 2 using a lathe.

(2) A hole 13 of a predetermined diameter is formed on the bottom side of the air nozzle 2.

(2) A pilot hole 14 of a predetermined diameter is formed on the top side of the air nozzle 2.

■ Harden the air nozzle 2.

(2) The hole 14 is cut into an elongated nozzle hole 9.

As a result, the nozzle hole 9 having the shape and dimensions as shown in FIG. 7 is processed.

■ EDM the long hole counterbore (air escape groove 9a) and the horizontal cut (air escape groove 11a) at the same time.

At this time, the maximum width dimension H(
(see Figure 3) is assumed to be 2.8 m.

(2) A pair of air nozzles 2.2 having nozzle holes 9 are manufactured separately from the plug gauge main body 1 using the above procedure.

C, boogey! (See Figures 1 and 2): ■ In the nozzle extension hole 12.12 of the plug gauge body 1,
Adhere the air nozzles 2.2 to each other with adhesive.

At this time, the longitudinal direction of the nozzle hole 9 of the air nozzle 2 is
The plug gauge body 10 is arranged so as to coincide with the circumferential direction.

■ Polish the outer peripheral surface 4 of the plug gauge body 1 to which the air nozzle 2 is attached.

■ Apply hard chrome plating to the outer peripheral surface 4 of the plug gauge body 1.

At this time, the second part of the air nozzle is subjected to plating prevention treatment.

■ Polish the outer circumferential surface of the plug gauge body 1 to an appropriate size,
The finished product is shown in Figure 1.

When the performance of the plug gauge configured as described above is compared with that of a conventional plug gauge with a round hole (circular hole) having the same opening cross-sectional area, the following results were found. It's clear.

(1) Measuring the inner diameter of the object W using a conventional plug gauge (see Figure 4 (a)) could not accurately measure objects with an axial width of less than 1 t@. With the plug gauge of the invention, it has become possible to measure plugs with an axial width of up to 3.4 inches.

(2) With the conventional plug gauge, it was not possible to measure the width of 10 mm (see Figure 4) when the width was smaller than 21 m, but with the plug gauge of the present invention, the width was 0.
．． It is now possible to measure grinding residues as small as 5 cranes, making it possible to measure more accurately.

(3) When measuring the inner diameter of a blind hole with a conventional plug gauge (see Figure 4 (d)), the center of the nozzle hole entered only 3.5 mm from the bottom, and the measurement was made when the nozzle hole was 3.5 mm away from the bottom. However, with the plug gauge of the present invention, it is 1.7 tm from the bottom.
It became possible to measure up to a distance of (2,8 (H) / 2 + 0.3 = 1.7 m), making it possible to measure the inner diameter dimension more accurately.

(Effects of the Invention) As detailed above, according to the present invention, various effects as listed below can be obtained.

According to the first invention, (al) Since the nozzle hole of the air nozzle is an elongated hole extending in the circumferential direction of the plug gauge main body, the size of the major axis that does not affect the measurement range of the plug gauge is determined by the size of the minor axis. By setting the cross-sectional area of the nozzle hole to be large enough to ensure back pressure above a certain pressure in accordance with the size,
The short axis can be set as small as possible.

Therefore, this is not possible with conventional plug gauges.
It is also possible to accurately measure annular products with a narrow axial width and blind holes with a shallow axial depth.

(b) If the nozzle hole is a round hole as in the past, if you try to reduce the hole diameter, you will need a booster that can obtain the desired indication with a small change in back pressure, but the present invention In this case, the short diameter, that is, the axial diameter can be made as small as possible without requiring a booster.

(C) Furthermore, the air nozzle is formed separately from the plug gauge body, making it easy to form an elongated nozzle hole.

(d) Highly accurate measurements can be expected without the measurement errors that were a problem with conventional dial gauges and cylinder gauges.Furthermore, measurement work does not require skill, compared to dial gauges and cylinder gauges. This makes measurement work much easier.

(el) Also, unlike dial gauges and cylinder gauges, no measurement pressure is applied, so even in the case of a thin ring, highly accurate measurement results can be obtained without deforming the shape.

(f) Due to the characteristics of the air micrometer, even if there is dust etc. attached to the surface of the object to be measured, the blowing action will blow away the dust. No measurement errors occur.

According to the second invention, the outer “
A plug gauge body having a circumferential surface and an air passage formed in the internal axial direction is provided with a pair of nozzle mounting holes communicating with the air passage, and a pair of air nozzles each having an elongated nozzle hole formed therein. After manufacturing each separately from the plug gauge body, the air nozzle is mounted and fixed in the nozzle mounting hole of the plug gauge body so that the major diameter direction of the nozzle hole coincides with the circumferential direction of the plug gauge body. Therefore, the nozzle hole of the air nozzle that satisfies the above conditions can be easily and accurately formed, thereby providing a relatively inexpensive plug gauge that can obtain the various effects described above. Can be done.

[Brief explanation of the drawing]

FIG. 1 is a plan view showing a plug gauge for a flow rate air micrometer according to an embodiment of the present invention, FIG. 2 is a sectional view taken along the line ll-ff in FIG. 1, and FIG. Plan view showing an enlarged view of the air nozzle of the plug gauge, No. 4
Figures (al (b), (C), and (d) are longitudinal cross-sectional views showing objects to be measured with the same plug gauge, Figure 5 is a plan view showing the main body of the plug gauge, and Figure 6 is a vertical cross-sectional view showing the object to be measured by the same plug gauge. The same cross-sectional view along the VI-VI line in Figure 5,
Figure 7 is a plan view showing the air nozzle of the plug gauge;
Fig. 8 is a cross-sectional view taken along the line ■-■ in Fig. 7, Fig. 9 is a theoretical explanatory diagram of a plug gauge, Fig. 10 is a schematic diagram showing a flow rate type air micrometer, and Fig. 11 is a conventional 12 is a sectional view corresponding to FIG. 2, and FIG. 13 is a plan view corresponding to FIG. 3. ■...Plug gauge body, 2...Air nozzle, 3
...Inner circumferential surface of the object to be measured, 4...Outer circumferential surface of the plug gauge body, 7...Air passage, 8...Air passage, 9
... Nozzle hole, 12... Nozzle mounting hole

Claims (2)

[Claims] (1) An air passage is provided inside the plug gauge body having an outer peripheral surface corresponding to the inner peripheral surface of the object to be measured, and a pair of air nozzles communicating with the air passage are provided facing the outer peripheral surface. The air nozzle is formed separately from the plug gauge body, and the nozzle hole is a long and narrow hole extending in the circumferential direction of the plug gauge body. Plug gauge for air micrometer. (2) A pair of nozzle mounting holes are formed in the plug gauge body, which has an outer circumferential surface corresponding to the inner circumferential surface of the object to be measured and an air passage formed in the internal axial direction, and a pair of nozzle mounting holes communicating with the air passage. On the other hand, a pair of air nozzles having elongated nozzle holes are manufactured separately from the plug gauge body, and the pair of air nozzles are installed in the nozzle mounting holes of the plug gauge body so that the long axis direction of the nozzle holes is A method for manufacturing a plug gauge for a flow rate type air micrometer, characterized in that the plug gauge is mounted and fixed so as to match the circumferential direction of the plug gauge body.