JPH03216501A - Small hole diameter measurement method - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for measuring the inner diameter dimension of a component having a small inner diameter, such as a miniature bearing.

(Prior technology) When trying to easily measure the diameter of a small hole, the common methods are to use a cylinder gauge type contact method, and to optically magnify the hole surface and measure the coordinates while observing. There is a microscope type non-contact type that reads the information.

(Problems to be Solved by the Invention) However, in the syringe-gauge type contact type, there is a limit to how small the measuring tip can be made, and it is difficult to measure the diameter of a small hole of several 1 or less.

Furthermore, with a microscope-type non-contact method, only the edge of the surface of the hole can be measured, and the inside of the hole cannot be measured.

The object of the present invention is to provide a method for measuring the inner diameter of a small hole, which can be measured by a simple measuring operation that can be used even in a factory.

(Means for Solving the Problems) In order to achieve the above object, the present invention positions the conductive gauge head so that the gap between the outer diameter of the conductive gauge head and the diameter surface of the hole to be measured is uniform, The capacitance according to the size of the gap is measured, and the hole diameter size is determined based on the measured capacitance value from a previously determined relationship diagram between the capacitance value and the hole diameter size.

(Function) Measure the capacitance after centripeting the probe with respect to the diameter of the measurement hole,
Using this relationship diagram between capacitance and hole diameter size, mff! The hole diameter dimensions can be found.

(Example) Next, an example of the present invention will be described with reference to the drawings.

1 is an insulator placed on an XY table 2. An object to be measured 3 having a small inner diameter is placed on this insulator 1. Reference numeral 4 denotes a probe having a steel ball attached to its tip, which is supported by a support member (not shown). Reference numeral 5 denotes a capacitance meter, which is connected to the measuring element 4 and the object to be measured 3 through conducting wires, respectively.

In this measurement method, the object to be measured 3 on the insulator 1 and the probe 4 are centered, but in this embodiment, the XY table 2
The object to be measured 3 is moved and centripetalized while slightly displacing the object.

This centripetal search uses the capacitance meter 5 to search for the position where the capacitance is minimum. Moeki centripetal is measuring point 4 instead of object to be measured 3
may be displaced.

If the centering is achieved as described above, the gap between the outer diameter of the probe 4 and the inner diameter of the object to be measured 3 is large! The capacitance determined by the Il is measured by a capacitance meter 5. Then, the hole diameter can be determined from the measured capacitance value using a diagram (see FIG. 2) in which the relationship between the hole diameter and capacitance is determined in advance for each probe 4.

Although it is necessary to determine the relationship between the hole diameter dimension and the capacitance value for each probe in advance as described above, in this measurement method, the capacitance value at the time of completion of the centripetal work becomes the immediate measurement value.

(Effects of the Invention) By applying capacitance to dimension measurement, the present invention enables non-contact measurement of inner diameter dimensions without deformation due to measuring force.

It is relatively efficient because the measured values are obtained at the same time as the centripetal work.

Furthermore, by using a steel ball as the measuring element, the diameter of the measuring element can be made small, and the measuring element can sufficiently cope with the diameter of a small hole, for example, from 0.5 mm to several mm.

Furthermore, by moving the probe up and down along the inner diameter surface,
Measurement at any position in the axial direction of the inner diameter surface is also possible.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing one embodiment of the present invention, and FIG. 2 is a diagram showing the relationship between capacitance value and dimensions. Explanation of the symbols 1 is an insulator, 2 is an XY table, 3 is an object to be measured, 4 is a probe, and 5 is a capacitance meter.

Claims (1)

[Claims] In the small hole diameter measurement method, the measuring element is positioned so that the gap between the outer diameter of the conductive measuring element and the diameter surface of the hole to be measured is uniform, and the capacitance depending on the size of the gap is measured,
A small hole diameter measurement method in which the hole diameter is determined based on the measured capacitance value from the relationship between the capacitance value and the hole diameter determined in advance.