JP2003028603A - Dimension measuring device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a dimension measuring device whose high accuracy and durability can be guaranteed. SOLUTION: A cylinder gage comprises a rod 3 which is housed inside an outer tube 1 so as to be slidable; a pair of gage heads 2a, 2b which are connected to one end of the rod 3 via a cam 6, which are installed so as to be movable to a direction at right angles to the longitudinal direction of the rod 3, and which come into contact with the inner wall of a hole or a groove in a specimen; and a display 5 which is installed on the side of the other end of the rod 3 and which displays a displacement amount converted to the rod 3 via the cam 6 at the gage head 2a. The rod 3, the gage heads 2a, 2b and the cam 6 are formed of carbon tool steel, and their outer circumferential faces are wholly coated with a thin layer 22 by an ion plating operation as an abrasion-resistant layer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dimension measuring instrument for measuring hole diameter, groove width and the like.

[0002]

2. Description of the Related Art A cylinder gauge is known as a size measuring instrument for measuring the hole diameter, groove width and the like of an object to be measured. The cylinder gauge converts the displacement of the contact point into the displacement of the rod in the direction perpendicular to this and measures the displacement. There are a method of using a cam and a method of using a wedge to convert this displacement.

[0003]

In the case of the cam type cylinder gauge, in order to ensure high accuracy, the contact point and the plane of the contact portion between the rod and the cam are perpendicular to the displacement direction, and the contact portion of the cam is It is required that the shape is a perfect sphere. Further, regarding durability, wear due to sliding friction of the contact surface between the cam and the rod or the contact point becomes a problem. Further, since the rod is slidably accommodated in the outer cylinder, and the probe is also slidably accommodated in the mounting portion, wear resistance of the rod and the probe is also required.

The present invention has been made in consideration of the above circumstances, and an object of the present invention is to provide a dimension measuring instrument capable of ensuring high accuracy and durability.

[0005]

According to the present invention, a rod slidably accommodated in an outer cylinder and one end of the rod are connected via a cam so as to be movable in a direction orthogonal to the longitudinal direction of the rod. A pair of measuring elements provided on the inner wall of the hole or groove of the object to be measured, and the displacement amount converted to the rod via the cam of the measuring element provided on the other end side of the rod. In the dimension measuring instrument having an indicator for displaying, the rod, the probe and the cam are formed of carbon tool steel, and the entire outer peripheral surface thereof is coated with a wear resistant layer by physical vapor deposition. It is characterized by

According to the present invention, the rod of the cam type cylinder gauge, the measuring element, and the cam for connecting them are made of carbon tool steel, and all of them have a wear-resistant layer formed by physical vapor deposition on the entire outer peripheral surface thereof. Coating. As a result, wear due to friction between the cam and the rod and the probe and wear on the sliding surfaces of the rod and the probe are prevented, and high accuracy and durability can be guaranteed.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows an external view of a cylinder gauge according to an embodiment of the present invention, and FIG. 2 shows a sectional structure of a main part thereof.

In this cylinder gauge, a pair of gauge heads 2a, 2b is provided at one end of an outer cylinder 1, and a display 5 is attached at the other end. Just below the display 5 is the grip 4.
Is provided. One of the measuring elements 2a and 2b is fixed, and the other 2a abuts on the inner wall 11 of the hole or groove of the DUT 10 and is displaced. Probe 2a
The displacement amount of the rod 3 is slidably housed in the outer cylinder 1.
Transmitted at a right angle to.

The tracing stylus 2a is slidably accommodated in the mounting member 7 in the guide 10 formed at the tip of the outer cylinder 1. When it comes into contact with the object to be measured, the guide 10 retracts and returns by the spring 9a. A small spring 9b for returning the probe 2a is inserted between the mounting member 7 and the probe 2a. As a conversion mechanism for transmitting the displacement of the probe 2a to the rod 3, a cam 6 is used as shown in FIG. On the contact surface of the cam 6 with the rod 1 and the probe 2a,
Spherical surfaces 8a and 8b are formed.

The rod 3, the measuring elements 2a and 2b and the cam 6 are all formed by grinding hardened carbon tool steel. As a wear resistant layer, titanium nitride (Ti
N) layer is coated. FIG. 2B shows an enlarged cross-sectional view of the main part of the probe 2a. The carbon tool steel 21 is processed into a cylindrical shape, and the entire surface including the hemispherical part at the tip and the end surface in contact with the cam 6 Is coated with a TiN layer 22. Although not shown, the same applies to the fixed-side measuring element 2b. Similarly, the entire surface of the rod 3, including the side peripheral surface and the contact end surface with the cam 6, is coated with a TiN layer. Also on the cam 6, the TiN layer is coated on the entire surface including the spherical surfaces 8a and 8b.

As described above, the rod 3, the measuring elements 2a, 2
By coating the entire b and the cam 6 with a TiN layer, the frictional surface and sliding surface between them and the contact surface of the probe with the object to be measured have sufficiently high hardness, wear is prevented, and Highly accurate life characteristics can be obtained.

Although TiN is used as the wear resistant layer in the above embodiment, other materials may be used to impart wear resistance and lubricity. For example, a laminated structure of molybdenum (Mo) and titanium (Ti), specifically, a three-layer structure of Ti / Mo / Ti can be used. Such a laminated structure can also be formed by ion plating. A sputtering method can also be used as the physical vapor deposition method.

[0013]

As described above, according to the present invention, the wear resistance layer is coated on all of the rod, the probe, and the cam connecting them, thereby obtaining a long-life and highly accurate characteristic of the cylinder gauge. be able to.

[Brief description of drawings]

FIG. 1 is an external view of a cylinder gauge according to an embodiment of the present invention.

FIG. 2 is a sectional view of a main part of the cylinder gauge.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Outer cylinder, 2a, 2b ... Measuring element, 3 ... Rod, 4 ... Grip part, 5 ... Indicator, 6 ... Cam, 7 ... Attachment part, 8a, 8
b ... spherical surface, 21 ... carbon tool steel, 22 ... TiN layer.

   ─────────────────────────────────────────────────── ─── Continued front page    F term (reference) 2F061 AA25 AA26 FF07 FF34 FF36                       FF61 FF73 GG01 HH02 HH45                       JJ02 JJ11 JJ23 JJ51 JJ67                       SS07 SS13 SS26                 2F062 AA34 AA36 BC48 CC10 EE01                       EE14 EE63 FF04 FF07 FF09                       FF25 GG90 HH13 HH22 LL02                       LL03

Claims (3)

[Claims] 1. A rod slidably accommodated in an outer cylinder, and a rod which is connected to one end of the rod through a cam so as to be movable in a direction orthogonal to the longitudinal direction of the rod. A pair of measuring elements that come into contact with the inner wall of the hole or groove, and a display that is provided on the other end side of the rod and that displays the amount of displacement converted to the rod through the cam of the measuring element. In the dimension measuring instrument, the rod, the tracing stylus and the cam are formed of carbon tool steel, and the entire outer peripheral surface thereof is coated with an abrasion resistant layer by a physical vapor deposition method. . 2. The wear-resistant layer is a titanium nitride layer formed by ion plating.
Dimensional measuring device described. 3. The dimension measuring device according to claim 1, wherein the wear resistant layer has a laminated structure of titanium / molybdenum / titanium formed by ion plating.