JPH044163Y2 - - Google Patents

Description

[Detailed description of the invention] <Industrial application field> The present invention relates to a tool for measuring the inner surface shape of a hole, and in particular,
It is a useful tool for remotely measuring the three-dimensional shape of undulations such as holes and irregularities that exist in narrow spaces that humans cannot access, along with their dimensions.

<Prior Art> It is often necessary in various fields to measure undulations such as holes and unevenness, and their three-dimensional shapes.

However, if there is a hole or unevenness inside a narrow gap that cannot be seen directly by humans, for example, as shown in FIG. If this is not possible, a device that can remotely measure the inner surface shape (including dimensions) of the hole 11 by some method is required.

Conventionally, a fiberscope has been used for this type of shape measurement.

<Problems that the invention aims to solve> However, even if a fiberscope is used, it is only possible to grasp the general condition of holes and irregularities, but accurate measurement of the three-dimensional shape including dimensions has to be abandoned. The current situation is that there is no such thing.

SUMMARY OF THE INVENTION In view of the above-mentioned problems, it is an object of the present invention to provide a tool for measuring the inner surface shape of a hole, which can accurately measure the three-dimensional shape of a hole or unevenness remotely.

<Means for solving the problems> The structure of the tool for measuring the inner surface shape of a hole according to the present invention which achieves the above-mentioned object includes an encoder rod and an encoder head slidably fitted to the encoder rod. An encoder for measuring the amount of axial movement, a mounting member from which an encoder rod projects, a detection member fixed to the encoder head and projecting in the radial direction, and a detection member surrounding the encoder rod and projecting from the mounting member. It is characterized by comprising a plurality of spring fingers arranged on the circumference around the rod, and a strain gauge for measuring the amount of radial movement attached to the spring fingers.

<Example> An example of the present invention will be described with reference to FIGS. 1 to 3. FIG. 1 is a sectional view of the tool for measuring the inner surface shape of a hole according to this embodiment, and FIG. 2 is a sectional view of an example of a hole to be measured.
FIG. 3 is a view taken along arrow A in FIG.

In FIGS. 1 and 3, reference numeral 8 denotes a plate-shaped mounting member, and a rod 6 of a magnetic encoder for measuring the amount of axial movement is protruded at right angles through a fixing plate 2 fixed to this mounting member 8. has been done. A head 5 of the same magnetic encoder is slidably fitted into the encoder rod 6. A spring 7 is attached between the encoder head 5 and the fixed plate 2 to maintain tension at all times. Reference numeral 4 denotes a plate-shaped stroke detection member, which is protruded from the tip of the encoder head 5 at right angles in the radial direction, and is movable in the axial direction along the encoder rod 6 together with the encoder head 5. . The outer diameter of the stroke detection member 4 is slightly larger than the diameter of the hole to be measured. Reference numeral 1 denotes a spring finger, which projects from the mounting member 8 at right angles through the fixing plate 2. Usually, a plurality of spring fingers 1 (four in this embodiment) are used, and are arranged on a circumference surrounding the encoder rod 6 and centered on the axis of the encoder rod 6. The free end of the spring finger 1 is designed to be able to move in the radial direction with extremely light force, and a protrusion B facing outward is formed at the tip so that it can easily come into contact with the inner surface of the hole. A strain gauge 3 is attached to the side surface of each spring finger 1 so as to be sensitive to minute movements in the radial direction of the tip of the spring finger 1. In this embodiment, since two spring fingers 1 intersect with the stroke detection member 4, a window hole 4a is provided in the stroke detection member 4 to ensure free movement of the spring fingers 1. If they do not intersect, there is no need for a window hole. The mounting member 8 may be moved up and down, back and forth, left and right, and rotated as required, but these may be driven manually or mechanically. The mechanical drive device is not essential to the present invention and will therefore be omitted.

The operation will be explained with reference to FIGS. 1 and 2.
In FIG. 2, 12 is a side wall of a cylindrical container, etc., and a hole 11 having a tapered portion expanding inward.
is open. First, the present tool 9 shown in FIGS. 1 and 2 is guided to approximately the center position of the hole 11 near the inner surface of the hole 11 by operating the mounting member 8. If necessary, use a fiberscope etc. Next, when the tool 9 is gradually brought closer to the hole 11 by moving the attachment member 8, the tip of the stroke detection member 4 comes into contact with point a on the inner surface of the hole 11. When the tool 9 is moved forward, the stroke detection member 4 and the encoder head 5 move back together against the spring 7, while the spring finger 1
The outer end B of contacts the point b of the tapered part of the hole 11. When the tool 9 is further advanced, the outer end B of the spring finger 1 reaches point c of the straight hole along the hole diameter of the tapered portion, and then moves to point d on the outer surface.

Since the arrangement dimensions of the spring finger 1 are known in advance, the outer end B of the spring finger 1
If the amount of movement in the radial direction after reaching point b is known, the radial position and dimensions of the hole 11 can be determined, but the amount of movement of the outer end B of the spring finger 1 can be determined accurately by the strain gauge 3. is measured. Furthermore, when the stroke detection member 4 comes into contact with point a on the surface of the hole 11, the encoder rod 6 resists the spring 7 and moves toward the hole 11.
1, the amount by which the outer end B of the spring finger 1 moves in the axial direction of the hole 11 is accurately measured. Thus, strain gauge 3
From the encoder readings, the exact positions of points b, c, and d of the hole 11 in the radial and axial directions can be determined. Further, the position of point a is determined from the extension of point c and point b. That is, the three-dimensional shape and dimensions of the inner surface of the hole 11 are determined.

Note that although the above explanation relates to the measurement of holes, it can be similarly applied to the measurement of undulations such as unevenness.

<Effects of the invention> As explained above, according to the invention, an encoder that measures the amount of movement in the axial direction is equipped with a strain gauge and a stroke detection member that are attached to a spring finger to measure the amount of movement in the radial direction. By using this in combination, it is possible to easily and accurately measure three-dimensional shapes such as holes and irregularities that are inaccessible to humans, along with their dimensions. Furthermore, the tool of the present invention is lightweight and small in terms of its constituent elements, and its manufacturing cost is low.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of a tool for measuring the inner surface shape of a hole according to an embodiment of the present invention, Fig. 2 is a sectional view showing an example of a hole to be measured, and Fig. 3 is a view taken in the direction of arrow A in Fig. 1. , 4th
The figure is a cross-sectional view of an example object with a hole requiring telemetry. In the drawing, 1 is a spring finger, 2 is a fixed plate, 3 is a strain gauge, 4 is a stroke detection member, 4
a is a window hole, 5 is an encoder head, 6 is an encoder rod, 7 is a spring, 8 is a mounting member, 9 is a tool of the present invention, 11 is a hole, and B is an outer end of a spring finger.

Claims (1)

[Scope of utility model registration request] An encoder for measuring an axial displacement having an encoder rod and an encoder head slidably fitted on the encoder rod, a mounting member from which the encoder rod protrudes, and an encoder fixed to the encoder head and arranged in a radial direction. a detection member protruding from the encoder rod; a plurality of spring fingers surrounding the encoder rod and protruding from the mounting member and disposed on a circumference centered on the encoder rod; and a plurality of spring fingers affixed to the spring fingers. A tool for measuring the inner surface shape of a hole, equipped with a strain gauge for measuring the amount of radial movement.