JP5713759B2 - Air micrometer - Google Patents

Description

  The present invention relates to an air (air) micrometer, and more particularly to an air micrometer that can accommodate a plurality of inner diameters.

  An air micrometer is widely used as a measuring device for measuring the inner diameter of a cylinder or the like. A general air micrometer has a plurality of strip-shaped guide portions extending in a direction parallel to the axis of a cylindrical surface, and at least one set of measuring elements (air sensors) provided between the plurality of guide portions. . The surface of each of the plurality of guide portions forms a part of a cylindrical surface whose diameter is a minute amount smaller than the inner diameter of the hole that is the object to be measured. Therefore, when the air micrometer is inserted into the hole, the center axis of the hole and the center axis of the air micrometer substantially coincide. Each air sensor has an air outlet. The surface of the ejection port is located near the cylindrical surface formed by the surfaces of the plurality of guide portions. The pair of air sensors are arranged so that the ejection port is located at a diagonal position across the central axis of the cylinder. There are cases where two air sensors are provided and four air sensors are provided at rotational positions shifted by 90 degrees. Hereinafter, a case where two air sensors are provided will be described as an example.

  The air micrometer is provided with an air supply port, and air is supplied from the outside by a constant pressure device. The air supplied to the air supply port is branched inside the air micrometer, and the branched air is supplied to each ejection port via the air path. Changes in the pressure, flow rate, or flow rate of the air supply are detected externally using a liquid column meter or dial gauge.

  Since the resistance of the air ejected from the ejection port changes according to the distance (gap) between the ejection port and the cylindrical inner surface of the object to be measured, it is detected as a change in pressure, flow rate or flow velocity. The detected value uniquely has a correspondence relationship with the gap. Usually, the gap between the inner diameters of the holes of the object to be measured, that is, the diameter is determined based on the detected value when measuring the master hole whose inner diameter is known.

When measuring with an air micrometer, the measurement accuracy is affected by the fact that the position and inclination of the air sensor are in a predetermined state with respect to the hole surface of the object to be measured. Therefore, a guide is used for the purpose of suppressing the positional deviation and inclination deviation of the air sensor.
The range of gaps that have a clear and unambiguous correspondence is limited. Therefore, an air micrometer is prepared and used for each inner diameter. When a guide is used, an air micrometer having a dedicated guide for each inner diameter has been prepared. In other words, the air micrometer was a measuring device dedicated to one type of inner diameter.

  On the other hand, in a contact-type inner diameter measuring device using a differential transformer or the like, in Patent Documents 1 and 2, etc., a plurality of guides that are rotatable in the radial direction are provided, and the spread angle of the guides according to the inner diameter of the hole of the object to be measured There has been proposed a device in which the inner diameters of various holes can be measured.

Japanese Patent Laid-Open No. 11-201704 JP 2010-019706 A

There is a demand for an air micrometer that can accommodate various inner diameters.
Therefore, it is conceivable to apply the configuration of the contact-type inner diameter measuring device provided with a plurality of guides rotatable in the radial direction to an air micrometer. However, when an air sensor is provided on a guide that is rotatable in the radial direction, it is inevitable that the inclination of the air sensor with respect to the hole surface changes with rotation. As described above, in order to perform measurement with good measurement accuracy, the position and inclination of the air sensor must be in a predetermined state with respect to the surface of the hole of the object to be measured. Then, there arises a problem that measurement cannot be performed with good measurement accuracy.

  An object of this invention is to implement | achieve the air micrometer which can measure various internal diameters with high precision.

  In order to solve the above-described problems, an air micrometer of the present invention connects a head member having an air sensor to a housing by two parallel leaf springs.

  That is, the air micrometer of the present invention includes a cylindrical casing, at least one set of head members each having an air ejection port on the outer surface, and at least one set of head members attached to the casing. At least one set of head holding mechanisms that are held symmetrically with respect to the axis, a head position changing mechanism that changes the position of at least one set of head members with respect to the central axis, and air at an air outlet of at least one set of head members Each of the at least one set of head holding mechanisms includes a base material attached to the housing and two parallel leaf springs connecting the base material and the head member. The head member is held movably only in a direction perpendicular to the central axis of the housing.

  By connecting the head member to the housing with two parallel leaf springs, it is possible to support the head member so as to be able to translate in the radial direction with respect to the central axis of the air micrometer. Therefore, even if the head member is moved in the radial direction with respect to the central axis of the air micrometer in accordance with the inner diameter of the hole to be measured, the inclination with respect to the central axis of the head member, that is, the inclination with respect to the hole surface does not change. As a result, the inner diameter can be measured with high accuracy.

  The head position changing mechanism is coaxial with the central axis, has a tapered surface in part, is provided on each head member, and is pressed against the tapered surface. A roller and a taper shaft moving mechanism that moves the taper shaft with respect to the housing can be provided.

  By connecting the head member to the casing with two parallel leaf springs, the head member can be constantly biased to the taper shaft. When the taper shaft is moved, the contact position with the taper surface of the roller changes, and the radial position of the head member changes. Since the roller provided in each head member is pressed against the taper surface, backlash and resistance at the time of movement are small, and high-precision movement is possible.

  The taper shaft preferably has at least one cylindrical surface parallel to the central axis provided between the taper surfaces. If the state in which the roller is in contact with this portion is set as a measurement state and a plurality of cylindrical surface portions parallel to the central axis between the tapered surfaces are provided, the inner diameter to be measured can be set stepwise. Since the radial position of the contact point with the tapered surface of the roller does not change within the predetermined movement range of the taper shaft, the radial position of the head member can be set with high accuracy.

The taper shaft moving mechanism is moved by, for example, an air cylinder mechanism.
The air supply mechanism connects at least one set of branch paths branched from an air path provided in the housing and at least one set of head member air ejection ports with at least one set of flexible tubes. Can be configured.

  Since the air micrometer of the present invention changes the position of the head member having the air sensor in the radial direction from the central axis according to the inner diameter to be measured, the inclination of the head member with respect to the central axis does not change. The inner diameter can be measured with high accuracy.

FIG. 1 is a perspective view illustrating an appearance of an air micrometer according to an embodiment. Drawing 2 is a figure showing the internal structure of the air micrometer of an embodiment. FIG. 3 is a view for explaining a parallel movement mechanism of the head member by the leaf spring. FIG. 4 is a diagram for explaining the movement of the head member accompanying the movement of the taper shaft. FIG. 5 is a diagram illustrating the shape of the tapered surface of the tapered portion of the tapered shaft.

  FIG. 1 is a perspective view illustrating an appearance of an air micrometer according to an embodiment. Moreover, FIG. 2 is a figure which shows the internal structure of the air micrometer of embodiment.

  The air micrometer 10 of the embodiment includes a cylindrical casing 31, two head members 21A and 21B, head holding base materials 32A and 32B attached to the casing 31, and head holding base materials 32A and 32B. And two parallel leaf springs 33AA and 33AB connecting the head members 21A and 21B; 33BA and 33BB, a cylinder member 34 attached to the housing 31, a bearing member 35, a taper shaft 41, and the cover 11 And an upper member 12.

  The upper member 12 is provided with a measurement air supply port 13 for supplying air supplied to the air sensor from the outside, and two cylinder air supply ports 14 for an air cylinder mechanism that moves the taper shaft 41. Yes.

  The taper shaft 41 is supported by a bush 47 provided on the housing 31 and a bush 48 provided on the bearing member 35 so as to be movable in the axial direction. The taper shaft 41 has a cylinder head 42 at one end. The cylinder head 42 is slidably held in the cylinder member 34, and moves to the right by supplying cylinder air into one chamber 36 in the cylinder member 34 separated by the cylinder head 42. By moving the cylinder air into the chamber 37, it moves in the left direction. In FIG. 2, a path for supplying cylinder air into the chamber 36 is indicated by a one-point difference line indicated by reference symbol Q, and a path for supplying cylinder air in the chamber 37 is indicated by a one-point difference line indicated by reference symbol R. Each is shown. Actually, the path is formed by a flexible tube or the like.

  On the other end side of the taper shaft 41, there is a taper portion 43 whose diameter changes. The rollers 24A and 24B provided on the head members 21A and 21B are pressed against the taper surface 44 of the taper portion 43, and the diameter of the taper surface 44 with which the rollers 24A and 24B come into contact with the movement of the taper shaft 41 is increased. As a result, the radial positions of the rollers 24A and 24B, that is, the radial positions of the head members 21A and 21B change.

  The head member 21 has a recess 24, and an air sensor 22 is attached in the recess 24. The air sensor 22 has an air outlet 23 for measuring the gap. The air supplied to the measurement air supply port 13 is supplied to the ejection port 23 of the air sensor 22 through a path provided in the upper member 12, the cylinder member 34 and the housing 31. In FIG. 2, a path for supplying measurement air to the air sensor 22 is indicated by a reference symbol P. Actually, the path is formed by a flexible tube or the like. This route is branched into two routes along the way, and is connected to the air sensor 22 provided on the head members 21A and 21B via the head holding base materials 32A and 32B. It is necessary to connect at least a flexible tube between the head holding substrate and the head member.

  The head holding substrates 32A and 32B, the head members 21A and 21B, and the leaf springs 33AA and 33AB; 33BA and 33BB have the same configuration. Hereinafter, the head holding base materials 32A and 32B will be described as the head holding base material 32, the head members 21A and 21B as the head member 21, and the leaf springs 33AA and 33AB; 33BA and 33BB as the leaf springs 33A and 33B.

  FIG. 3 is a diagram illustrating a parallel movement mechanism of the head member 21 by the leaf springs 33A and 33B.

  The head holding base material 32 is fixed to the housing 31. As shown in FIG. 3A, the head holding base 32 and the head member 21 are connected by two parallel leaf springs 33A and 33B. The leaf springs 33A and 33B are fixed so as to be parallel to the head holding substrate 32 and the head member 21, and can be bent only in a direction perpendicular to the leaf springs 33A and 33B including the illustrated Z direction.

  Further, both ends of the plate springs 33A and 33B are fixed to the head holding substrate 32 and the head member 21, respectively, and a plate spring presser 38 is provided at the center of the plate springs 33A and 33B. Limit the bending position of parallel leaf springs. Therefore, the parallel leaf springs 33A and 33B are bent as shown in FIG. 3B, and the head member 21 moves in parallel while maintaining the inclination. In FIG. 3B, reference numeral 39 indicates a flexible tube that connects the air path of the head holding base 31 and the air sensor 22 provided on the head member 21.

  4A and 4B are views for explaining the movement of the head members 21A and 21B accompanying the movement of the taper shaft 41. FIG. 4A shows a case where the first inner diameter is measured, and FIG. 4B shows a case where the first inner diameter is smaller than the first inner diameter. The case of measuring the reverence of 2 is shown. 5A and 5B are views for explaining the shape of the tapered surface 44 of the tapered portion 43 of the tapered shaft 41. FIG. 5A shows the entire tapered portion 43, and FIG. 5B shows the cylindrical surface portion 45 in the middle of the tapered surface 44. It is an enlarged view.

As shown in FIGS. 5A and 5B, the tapered portion 43 has two cylindrical surface portions 45, and both sides of the cylindrical surface portion 45 are tapered surfaces 44 whose diameter changes linearly. .
FIG. 4A shows a state in which the cylinder air is supplied to the chamber 36 in FIG. 2 to move the taper shaft 41 to the right, and the rollers 24A and 24B provided on the head members 21A and 21B are connected to one cylindrical surface portion 45. Shown in contact with the top. The head members 21A and 21B are urged in the direction toward the central axis 46 of the air micrometer 10 by plate springs 33AA and 33AB; 33BA and 33BB, and the rollers 24A and 24B are pressed against the cylindrical surface portion 45. The cylindrical surface portion 45 has a certain width, and within this width range, the radial positions of the rollers 24A and 24B are the same even if the movement position of the taper shaft 41 is shifted. Accordingly, the movement accuracy of the taper shaft 41 is allowed to have an error in this range.

  In this state, the position of the outer surface of the air sensor 22 fixed to the head members 21A and 21B, that is, the distance between the surfaces of the ejection openings 23A and 23B of the two air sensors fixed to the head members 21A and 21B, respectively. Becomes a predetermined first value. This first value is made to correspond to the diameter of the hole of the first type object to be measured.

  Next, when measuring the diameter of the hole of the second type object to be measured, which is slightly smaller than the first type diameter, as shown in FIG. Then, the taper shaft 41 is moved to the left side so that the rollers 24A and 24B provided on the head members 21A and 21B are in contact with the other cylindrical surface portion 45. Even in this state, the rollers 24 </ b> A and 24 </ b> B are pressed against the cylindrical surface portion 45.

  In this state, the position of the outer surface of the air sensor 22 fixed to the head members 21A and 21B, that is, the distance between the surfaces of the ejection openings 23A and 23B of the two air sensors fixed to the head members 21A and 21B, respectively. Becomes a predetermined second value smaller than the first value. This second value corresponds to the hole diameter of the second type object to be measured.

  4A and 4B, the positions of the ejection ports 23A and 23B are not only displaced in the radial direction but also slightly changed in the direction of the central axis 46 (Z direction), but are very small. It is a quantity and does not become a problem.

  As described above, when measuring the diameter of the hole of the first type object to be measured, the taper shaft 41 is moved to the right side to the state shown in FIG. Calibration is performed by measuring a master work as a reference, and then the tip of the air micrometer of the embodiment is inserted into the hole of the object to be measured, and the ejection openings 23A and 23B are positioned at a depth at which the diameter of the hole is measured. And measure. When measuring the diameter of the hole of the second type object to be measured, the taper shaft 41 is moved to the left side to the state shown in FIG. Measurement is performed for calibration, and then the tip of the air micrometer of the embodiment is inserted into the hole of the object to be measured, and the ejection ports 23A and 23B are positioned at a depth for measuring the diameter of the hole.

  As described above, according to the diameter of the hole to be measured, the air micrometer of the embodiment can measure the inner diameter with the optimum gap by moving in the radial direction while maintaining the inclination of the air sensor. . In the embodiment, since parallel leaf springs are used, the inclination of the air sensor can be maintained with high accuracy and the structure can be simplified.

  Although the embodiment of the present invention has been described above, it goes without saying that various modifications are possible. For example, in the embodiment, an example in which two head members are provided has been described, but it is also possible to provide four head members.

  Further, in the embodiment, the taper shaft is moved by the air cylinder. However, the taper shaft provided with a screw may be rotated by a motor or the like to move in the central axis direction.

  Furthermore, in the embodiment, an example in which two cylindrical surface portions are provided has been described, but three or more can be used. In this case, it is desirable to use a moving mechanism that rotates a taper shaft provided with a screw by a motor or the like to move in the direction of the central axis.

DESCRIPTION OF SYMBOLS 10 Air micrometer 21, 21A, 21B Head member 22 Air sensor 23 Ejection port 24A, 24B Roller 31 Case 32A, 32B Head holding base material 33AA, 33AB, 33BA, 33BB Leaf spring 34 Cylinder member 34
41 Tapered shaft 42 Cylinder head 43 Tapered portion 44 Tapered surface 45 Cylindrical surface portion

Claims (1)

A cylindrical housing;
At least one set of head members each having an air outlet on the outer surface;
At least one set of head holding mechanisms attached to the housing and holding the at least one set of head members symmetrically with respect to the central axis;
A head position changing mechanism that changes a position of the at least one set of head members with respect to the central axis;
An air supply mechanism for supplying air to the air ejection port of the at least one set of head members,
Each of the at least one set of head holding mechanisms includes:
A base material attached to the housing;
Wherein with the two parallel leaf springs for connecting the base and the head member, the, only movably held in the direction perpendicular to the head member to the central axis of the casing,
The head position changing mechanism is
A tapered shaft that is coaxial with the central axis, has a tapered surface in part, and is slidably held with respect to the housing;
A roller provided on each head member and pressed against the tapered surface;
A taper shaft moving mechanism for moving the taper shaft relative to the housing;
The taper shaft has at least one cylindrical surface parallel to the central axis provided between the taper surfaces .

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