JPH06185938A - Innerdiameter measuring device - Google Patents

Abstract

PURPOSE:To provide an inner diameter measuring device excellent in reliability and stability and can measure the inner diameter of an object to be measured with high accuracy with no restriction on the material of the object to be measured. CONSTITUTION:In an inner diameter measuring device having a pair of contactors 3A, 3B disposed movably toward/from a body 1 and coming into contact with the inner wall of a hole made in an object to be measured, a displacement detector 13 for measuring the distance between the pair of contactors is disposed on a line connecting the contact points of the pair of contactors 3A, 3B with the inner wall of the hole made in the object. Since error factor is reduced and Abbe error can be neglected, highly accurate measurement can be expected. Furthermore, since conventional wedge member is not employed, defects due to the wedge member can be eliminated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inner diameter measuring device.
More specifically, the present invention relates to an inner diameter measuring device that measures the inner diameter of a measured object from the distance between a pair of contacts that contact the inner wall of the hole of the measured object.

[0002]

BACKGROUND ART Conventionally, as a structure of an inner diameter measuring device,
A plurality of contacts that contact the inner wall of the hole of the object to be measured approach each other,
The shaft member is provided so as to be separable, and the shaft member is displaceable in a direction orthogonal to the approaching or separating direction thereof, and the displacement of the contacting member in the approaching or separating direction is converted into the displacement of the shaft member via the wedge member. There is known a structure in which the displacement of the shaft member is displayed by a dial gauge. The contacts are biased in a direction in which they are separated from each other by biasing means such as a spring.

In the measurement, the contacts are inserted into the hole of the object to be measured in a state of being close to each other against the biasing means such as a spring, and then the contacts are separated from each other by the biasing force of the biasing means. Displace in the direction. Then, since the contactor comes into contact with the inner wall of the hole of the object to be measured, the hole diameter of the object to be measured can be measured by reading the value of the dial gauge at that time.

[0004]

However, the above-mentioned conventional inner diameter measuring instrument has the following problems. There is a limit to the processing accuracy of the wedge-shaped member. Therefore, the measurement accuracy is about 2 μm, which is not very good. Since the wedge-shaped member is displaced while sliding against the contact,
Easy to wear. The wear of the wedge-shaped member directly affects the measurement accuracy, leading to a drawback of lack of reliability. Since the displacement in the approaching or separating direction of the contactor is converted into the displacement in the axial direction of the shaft member via the wedge-shaped member, the contact force must be set to a certain degree. That is, the biasing force of the biasing means such as the spring must be set to a large value. Therefore, if the material to be measured is soft, the material to be measured will be deformed and cannot be measured, so that the material to be measured is restricted. Also, the effective measurement range is narrow in relation to the structure of. Therefore, if the measurement range is to be expanded, a plurality of types of contacts having different diameters must be prepared in advance, which imposes a heavy economic burden.

Here, the object of the present invention is to eliminate all such drawbacks of the prior art and to have excellent reliability and stability.
An object of the present invention is to provide an inner diameter measuring instrument that can measure the inner diameter of a measured object with high accuracy without being restricted by the material of the measured object.

[0006]

Therefore, the inner diameter measuring instrument of the present invention comprises a main body, a pair of contactors provided on the main body so as to be close to and away from each other, and in contact with the inner wall of the hole of the object to be measured, and the pair of contactors. In an inner diameter measuring instrument having an urging means for urging the contacts in directions away from each other, a pair of contacts on an approximate line connecting respective contact points of the pair of contacts in contact with the inner wall of the hole of the object to be measured. It is characterized in that a displacement detector for measuring the distance between them is arranged.

[0007]

In the measurement, the pair of contacts are inserted into the measurement hole of the object to be measured with the pair of contact elements being close to each other against the biasing force of the biasing means, and then the pair of contacting elements are contacted by the biasing force of the biasing means. Displace the child away from each other. Then, since the pair of contacts come into contact with the inner wall of the hole of the object to be measured, the distance between the pair of contacts at that time is detected by the displacement detector.
At this time, since the displacement detector directly detects the distance between the pair of contacts on the line connecting the contact points of the pair of contacts, all the conventional problems can be solved. That is, unlike the related art, the displacement of the contact is not converted into the displacement of the shaft member by using the wedge-shaped member and the displacement is not detected, so that the problems (1) to (3) described above can be eliminated.

[0008]

The preferred embodiments of the inner diameter measuring device of the present invention will be described below in detail with reference to the accompanying drawings.
FIG. 1 is a front view showing an inner diameter measuring instrument of the present embodiment, and FIG. 2 is an exploded perspective view showing a main part thereof. In these figures, 1
Is a cylindrical body that also serves as a grip. A slit 2 is formed from a substantially intermediate position in the longitudinal direction of the main body 1 to the front end, and a front end portion of the main body 1 divided by the slit 2 has a substantially hemispherical contact 3A that contacts the inner wall of the hole of the object to be measured. , 3B are integrally formed. That is, the pair of contacts 3A, 3B are provided at the tip of the main body 1 so that they can approach and separate from each other by the slit 2.

A shaft member 4 is inserted inside the main body 1 so as to be displaceable in the axial direction, that is, in the direction orthogonal to the approaching and separating directions of the contacts 3A, 3B. Shaft member 4
A cone member 5 having a tapered surface in contact with the inner ends of the contacts 3A and 3B is integrally provided at the tip of the cone. On the base end side, a release piece 6 is provided at the end portion protruding from the main body 1, and a spring receiving plate 7 is provided closer to the intermediate portion than that. Spring receiving plate 7 and stopper plug 8 on the base end side of the main body 1
And a spring 9 as a biasing means for constantly biasing the pair of contacts 3A, 3B in a direction in which they are separated from each other.
Is provided.

The contactors 3A and 3B have wedge-shaped hole portions 11A and 11B, which are inclined in a conical shape at the upper portions of the contact surfaces which face each other and which gradually incline downward toward the center.
With a rectangular cutout 12 at the bottom.
A and 12B are formed respectively. Wedge-shaped hole 1
The tapered surface of the cone member 5 is in contact with 1A and 11B. Displacement detection is performed between the inner bottom surfaces of the notches 12A and 12B to detect the distance between the pair of contactors 3A and 3B on the line connecting the contact points of the pair of contactors 3A and 3B that contact the inner wall of the hole of the object to be measured. The container 13 is arranged. Displacement detector 13
As shown in FIG. 2, the scale 15B is attached to the inner bottom surface of the cutout 12B through a support plate 14B in parallel with the approaching and separating directions of the contacts 3A and 3B, and the cutout 1B.
2A through the support plate 14A on the inner bottom surface of the scale 15
The micro encoder 15A is disposed so as to face B.

Here, the micro encoder 15A is, for example, [Optical Encoder / Optical Component of "Measurement and Control" Vol. 31, No. 6,656-659, published by the Society of Instrument and Control Engineers, June 10, 1992. The micro encoder described in [Application] can be used. Micro encoder 1
5A is connected to a signal processing circuit and a power supply circuit 17 through a power supply / signal line 16 printed and printed along the outer surface of the contactor 3A and the axial direction of the outer surface of the main body 1. These circuits 17 are provided on a plate 18 provided at a substantially middle portion of the main body 1. Plate 18
In addition to the circuit, a digital display unit 19 for displaying a value corresponding to the distance between the contacts 3A and 3B obtained by the signal processing circuit is provided in the.

Next, the operation of this embodiment will be described. In the measurement, the distance between the pair of contacts 3A and 3B is shortened. To do this, first grasp the middle of the body 1 with one hand,
The release piece 6 is pulled upward with the other hand against the biasing force of the spring 9. Then, since the cone member 5 moves upward via the shaft member 4, the pair of contacts 3A, 3B move in a direction in which they approach each other. As a result, the distance between the pair of contacts 3A and 3B is shortened.

In this state, the pair of contacts 3A, 3
When B is inserted into the hole of the object to be measured and then the releasing piece 6 is returned according to the urging force of the spring 9, the cone member 5 moves downward via the shaft member 4, so that the pair of contacts 3
A and 3B are moved away from each other. Eventually,
When the outer surfaces of the pair of contacts 3A, 3B come into contact with the inner wall of the hole of the object to be measured, further separation is stopped. During this period, the distance between the pair of contacts 3A, 3B is detected by the displacement detector 13 and then digitally displayed on the digital display unit 19 via the signal processing circuit 17, so that the pair of contacts 3A, 3B By reading the value on the digital display unit 19 when the separation is stopped, the hole diameter of the measured object can be measured.

Therefore, according to the present embodiment, the pair of contacts 3 provided at the tip of the main body 1 so that they can approach and separate from each other.
Since the displacement detector 13 for detecting the distance between the pair of contacts 3A, 3B is arranged between A and 3B, that is, the distance between the pair of contacts 3A, 3B is directly detected. There are few error factors and the displacement detector 13
Is a pair of contactors 3A and 3B that contact the inner wall of the hole of the object to be measured.
Since it is arranged on the line connecting the contact points, the Abbe error can be ignored and the hole diameter of the measured object can be measured with high accuracy.

This is not the conventional structure in which the displacement in the approaching and separating directions of the contactor is converted into the axial displacement of the shaft member through the wedge-shaped member and the displacement is detected. All of the conventional drawbacks associated with the structure can be eliminated. That is, there is no increase in cost associated with the processing of the wedge-shaped member and no deterioration in reliability and stability due to wear. Further, since the measuring pressure can be set small, the material of the measuring objective is not limited, and since the displacement detector 13 is used, the measuring range can be widened and it is not necessary to prepare a plurality of types of contacts. .

Although the present invention has been described above with reference to the preferred embodiment, the present invention is not limited to this embodiment, and various improvements and design changes can be made without departing from the scope of the present invention. It is possible.

For example, the structure for allowing the pair of contacts 3A, 3B to approach and separate from each other is not limited to the structure of the slit 2 of the above embodiment, but as shown in FIG. 3, a pair of leaf springs parallel to each other. You may make it arrange | position 21A, 22A, 21B, 22B between each contactor 3A, 3B and the main body 1. The measurement pressure in this case is the leaf springs 21A, 22.
It can be arbitrarily set by the spring constants of A, 21B and 22B. The shapes of the contacts 3A and 3B shown in FIG. 3 are such that the semi-ring shaped outer peripheral surface is formed into a spherical shape.

Further, the disposition of the scale 15B and the micro encoder 15A is not limited to the disposition of the above embodiment, but they may be disposed so as to face each other in the vertical direction as shown in FIG. Further, the scale 15B and the micro encoder 15A are not limited to the light reflection type described in the above embodiment, but may be a light transmission type as shown in FIG.
Alternatively, not limited to these, any type such as an electrostatic capacitance type or an electromagnetic type may be used as long as it can detect the distance between the pair of contacts 3A and 3B with high accuracy.

[0019]

As described above, according to the inner diameter measuring device of the present invention, the displacement detector for directly detecting the distance is provided between the pair of contacts provided on the main body so as to be close to and away from each other. Therefore, all the conventional problems can be solved. In other words, it is expected that the reliability and stability are excellent and that the inner diameter of the measured object can be measured with high accuracy without being restricted by the material of the measured object.

[Brief description of drawings]

FIG. 1 is a front view showing an embodiment of the present invention.

FIG. 2 is an exploded perspective view showing a main part of the embodiment.

FIG. 3 is an exploded perspective view showing a modified example of a configuration in which a pair of contacts can approach and separate from each other.

FIG. 4 is an exploded perspective view showing another example of the arrangement of the scale and the micro encoder.

FIG. 5 is an exploded perspective view showing an example in which a displacement detector is a light transmission type.

[Explanation of symbols]

 1 Main Body 2 Slits 3A, 3B Contact 4 Shaft Member 5 Cone Member 6 Release Piece 9 Spring (Biasing Means) 13 Displacement Detector 15A Micro Encoder 15B Scale

Claims (1)

[Claims] 1. A main body, and a pair of contacts provided on the main body so as to be close to and away from each other and in contact with an inner wall of a hole of an object to be measured.
In an inner diameter measuring instrument having an urging means for urging the pair of contacts in directions away from each other, a pair is formed on an approximate line connecting the contact points of the pair of contacts that contact the inner wall of the hole of the object to be measured. An inner diameter measuring instrument, characterized in that a displacement detector for measuring the distance between the contacts of is arranged.