JPH08159722A - Product dimension measuring instrument - Google Patents

Abstract

PURPOSE: To accurately measure product dimension by rotating a measurement object, applying light in a direction which is parallel with the rotary axis by partially screening light at the edge part of the object, and providing a line sensor on the opposite side of a light source along a rotary radius direction. CONSTITUTION: A product 24 is fitted to a rotary holding member and is rotated by a step motor 22 and a laser light source 26 is provided on the same side as the motor 22. A one-dimensional line sensor 30 is provided on the opposite side of the light source 26 while sandwiching the product 24 and laser beams 28b other than light screened by an inner-diameter part 24a of the product 24 are detected. The output of the sensor 30 is minimized or maximized at a position where a rotary center, the center of the product 24, and the longer direction of the sensor 30 are in one line. Therefore, the inner diameter of the product 24 can be calculated by adding the distance from the rotary center to the minimum value and the distance from the rotary center to the maximum value by a judgment circuit 32, thus accurately obtaining the inner diameter of the product 24 when the inner diameter is nearly round even if the product 24 is mounted while being set eccentrically.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inexpensive product size measuring apparatus capable of measuring the outer diameter, inner diameter, etc. of a product with high accuracy.

[0002]

2. Description of the Related Art FIG. 6 is a schematic view of a product size measuring apparatus according to a conventional example, and FIG. 7 is a plan view taken along line VII-VII shown in FIG. As shown in FIGS. 6 and 7, in the conventional dimension measuring device 2, the laser light source 6 is arranged below the product 4 whose inner diameter is to be measured. From the laser light source 6,
A laser beam 8a having a width larger than the maximum inner diameter of the product 4 is irradiated, and a part of the laser beam 8a hits the inner edge of the product and is shielded.

A one-dimensional line sensor 10 is arranged on the opposite side of the product 4 from the laser light source 6. In the line sensor 10, the light receiving elements are linearly arranged and one-dimensionally detects light in the line direction. As shown in FIG. 7, product 4
Is a line sensor 10 by means of moving means (not shown).
Of the line sensor 10 by moving in a direction A substantially perpendicular to the longitudinal direction of the
Sequentially measures the width x of the laser beam 8b emitted from the laser light source 6 and partially shielded by the inner edge of the product and incident. Then, the maximum of the width x of the light measured by the line sensor 10 is set as the first temporary inner diameter of the product 4.

Next, at the position where the product 4 is rotated 90 degrees,
The laser light source 6 is attached to the moving means and is similar to the above.
The width x of the laser beam 8b which is emitted from the laser beam and is incident on the inner edge of the product while being partially shielded is sequentially measured. Then, the maximum of the light width x measured by the line sensor 10 is set to the second value of the product 4.
Use a temporary inner diameter.

Next, the average of the first temporary inner diameter and the second temporary inner diameter of the product 4 obtained as described above is calculated and used as the measured inner diameter of the product.

[0006]

However, in the measuring method using the measuring device 2 shown in FIGS. 6 and 7, there is a possibility that the product dimension cannot be accurately measured due to a deviation when the product 4 is set on the moving means. . Further, in the measuring device 2 shown in FIGS. 6 and 7, there is no problem when the product 4 has a small diameter, but when the product diameter becomes large, it is necessary to enlarge both the laser light source 6 and the line sensor 10. However, there is a problem that the device becomes too expensive.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a product size measuring device which is capable of measuring the outer diameter, the inner diameter and the like of a product with high accuracy and is small in size and inexpensive. And

[0008]

In order to achieve the above object, a product size measuring apparatus according to the present invention comprises a rotating means for rotating a product of a size measuring object, and a direction substantially parallel to a rotation axis of the product, A light source that emits light so as to be partially shielded at the edge of the product, and a position that is apart from the center of rotation of the product by a predetermined distance so as to receive light that is partially shielded at the edge of the product. , A line sensor arranged on the opposite side of the light source along the radial direction of rotation.

As the light source, for example, a laser light source is used. The cross section of the laser light emitted from the laser light source has an elongated shape such as an ellipse. The product to be measured is, for example, an oil seal part or a ring-shaped member such as an O-ring, and the dimension to be measured is, for example, the inner diameter or the outer diameter of the product.

[0010]

A method for measuring the inner diameter or the outer diameter of a product using the product dimension measuring device according to the present invention will be described. First, the product is attached to the rotating means, and while rotating the product, light is emitted from the light source toward the inner diameter edge portion or the outer diameter edge portion of the product. A part of the irradiated light is blocked by the inner diameter edge portion or the outer diameter edge portion of the product, while the other light is incident on the line sensor.

The line sensor measures the boundary between the light incident on the line sensor and the light-shielding portion as the product rotates. Assuming that the measurement part of the product is a perfect circle and the center of rotation of the product and the center of rotation of the rotation means are deviated, the position of the boundary between the light incident on the line sensor and the light-shielding part will be the same as the rotation of the product. Change.

The inner diameter or outer diameter of the product can be calculated by obtaining the maximum value and the minimum value of the distance from the rotation center of the product to the boundary and adding them. Also, as another method, the rotational position of the product is 0 °, 90 °, 180 °.
From the center of rotation of the product,
The inner diameter or the outer diameter of the product can be calculated by obtaining the distances to the positions of the boundaries detected by the line sensor, adding them all, and dividing by two.
With this method, even if the measured portion of the product is not a perfect circle but is close to an ellipse, the average inner diameter or outer diameter can be obtained.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The product dimension measuring apparatus according to the present invention will be described in detail below with reference to the embodiments shown in the drawings. FIG. 1 (A)
1 is a schematic configuration diagram of a product size measuring apparatus according to an embodiment of the present invention, FIG. 1B is a sectional view of the laser beam shown in FIG.
2A is a plan view of a product to be measured by the measuring device shown in FIG. 1, FIG. 2B is a sectional view taken along line BB of FIG. 2A, and FIG. FIG. 5A is a plan view showing the relationship between the product and the line sensor, FIG. 4 is a graph showing the output result of the line sensor with the rotational position of the product as the horizontal axis.
(D) is a schematic diagram showing the relationship between the rotational position of the product and the output result of the line sensor.

As shown in FIG. 1 (A), the product dimension measuring apparatus 20 according to this embodiment has an oil seal member or an O
This is a device for measuring the inner diameter of a ring-shaped product 24 such as a ring. The overall shape of the ring-shaped product 24 is shown in FIG. The product 24 shown in FIG. 2 is mounted on a rotation holding member which is omitted in FIG. 1, and is rotated by a step motor 22 as a rotating means.

In this embodiment, a laser light source 26 is arranged on the same side as the step motor 22. The laser light source 26 of the present embodiment does not need to emit a laser beam having a width larger than the inner diameter of the inner diameter portion 24a of the product 24, and has a width enough to irradiate a part of the inner diameter portion 24a of the product 24.
It is sufficient to emit 8a. An example of the laser light 28a is shown in FIG. The laser beam 28a is not particularly limited as long as it has a shape elongated in the rotation radius direction of the product 24, and may have an elliptical shape as shown in FIG. 1B, for example.

A one-dimensional line sensor 30 is arranged on the opposite side of the laser light source 26 with the product 24 in between. The line sensor 30 includes light receiving elements such as CCDs arranged linearly, and is located at a position separated from the center of rotation of the product 24 by a predetermined distance and at a position facing the laser light source 26. As shown, they are arranged along the radial direction of rotation. A determination circuit 32 is connected to the line sensor 30 as shown in FIG. The determination circuit 32 calculates the product size from the output of the line sensor 30.

As shown in FIG. 1, the line sensor 30 detects laser light 28b other than the light emitted from the laser light source 26 and shielded by the inner diameter portion 24a of the product 24. Step motor 22 (1 step is, for example, 0.
FIG. 4 shows the result of imaging the inner diameter portion 24a of the product 24 by the line sensor 30 while rotating the product 24 at (72 degrees). In this embodiment, the length of the line sensor 30 is about 3.3 mm.

In FIG. 4, a curve α is the locus of the boundary between the laser beam incident on the line sensor 30 and the light-shielding portion when the horizontal axis is the rotation angle position of the product. As shown in FIG. 4, the trajectory α of the boundary is 36
It changes with 0 degree as one cycle. It is thought that the reason why the product changes with 360 degrees as one cycle is that the product is eccentrically attached to the rotation holding member.

Next, a method for calculating the inner diameter of the product 24 using the measuring device 20 shown in FIG. 1 will be described with reference to FIG. As shown in FIG. 5, assuming that the center 40 of the product 24 is eccentrically attached to the rotation center 42, the line sensor 30 is rotated while rotating the product 24 in the arrow B direction.
As a result of detecting the laser light in the above, the output of the line sensor 30 becomes the minimum (min) according to the positional relationship of FIG. 5B, and the maximum output (max) is the position of FIG. 5D. It is a relationship. The position where the output of the line sensor 30 is minimum or maximum is a position where the rotation center 42, the product center 40, and the longitudinal direction of the line sensor 30 are aligned. Therefore, the distance R from the center of rotation 42 to the minimum value
_{If the min} and the distance R _max from the rotation center 42 to the maximum value are added by the determination circuit 32 shown in FIG.
The inner diameter of can be calculated.

In the above-described embodiment, even if the product 24 is eccentrically attached to the rotation holding member, the product 2
When the inner diameter portion of 4 is substantially a perfect circle, the inner diameter of the product 24 can be accurately determined. When the inner diameter portion of the product is not a perfect circle but is close to an ellipse, the average value of the inner diameter of the product can be accurately obtained by adopting the following method.

In this method, the output value (from the rotation center 42) by the line sensor 30 at each point (rotational position is 0 °, 90 °, 180 °, 270 °) in FIGS. 5A to 5D. Determination circuit 32 shown in FIG.
Then, all of these output values are added and this value is divided by 2. Then, the average value of the diameters at the orthogonal rotation positions is obtained. This value is a reasonable value as the average value of the inner diameter of the product 24.

In this embodiment, it is not necessary to irradiate a laser beam having a width corresponding to the inner diameter of the product 24, it is not necessary to prepare a line sensor corresponding to the width, and the apparatus is not enlarged. Moreover, in the present embodiment, even if the center 40 and the rotation center 42 of the product 24 are deviated, the inner diameter of the product 24 can be measured extremely accurately.

The present invention is not limited to the above-mentioned embodiments, but can be variously modified within the scope of the present invention. For example, although the laser light source 26 is used as the light source in the above-described embodiment, a light source that emits other types of light may be used in the present invention.

The laser light source 26 and the line sensor 30 are also provided.
Is located on the opposite side of the product 24. As long as they are located on the opposite side, the positional relationship between them does not matter.
The laser light source 26 may be located above the line sensor 30, contrary to the positional relationship shown in FIG.

Further, in the above-mentioned embodiment, the inner diameter of the product 24 is obtained, but the laser light source 26 and the line sensor 30 are used.
The outer diameter of the product 24 can be obtained in the same manner as in the above-described embodiment by only changing the installation position of the product.

[0026]

As described above, according to the present invention, it is not necessary to irradiate the laser beam having the width corresponding to the inner diameter or the outer diameter of the product, and it is necessary to prepare the line sensor corresponding to the width. Nor. Therefore, in the present invention, the device does not become large and the device becomes inexpensive. Moreover, in the present invention, even if the product is eccentrically attached to the rotating means, it is possible to measure the dimensions such as the inner diameter or the outer diameter of the product very accurately.

[Brief description of drawings]

1A is a schematic configuration diagram of a product size measuring apparatus according to an embodiment of the present invention, and FIG. 1B is a cross-sectional view of the laser beam shown in FIG. 1A.

2 (A) is a plan view of a product to be measured by the measuring device shown in FIG. 1, and FIG. 2 (B) is B of FIG. 2 (A).
It is sectional drawing which follows the -B line.

FIG. 3 is a plan view showing a relationship between a rotating product and a line sensor.

FIG. 4 is a graph showing an output result of a line sensor with the rotational position of a product as the horizontal axis.

5A to 5D are schematic diagrams showing the relationship between the rotational position of the product and the output result of the line sensor.

FIG. 6 is a front view of a product dimension measuring device according to a conventional technique.

7 is a plan view taken along line VII-VII shown in FIG.

[Explanation of symbols]

 20 ... Product dimension measuring device 22 ... Step motor 24 ... Product 24a ... Inner diameter part 26 ... Laser light source 28a, 28b ... Laser light 30 ... Line sensor 32 ... Judgment means 40 ... Product center 42 ... Rotation center

Claims (1)

[Claims] 1. A rotating means (22) for rotating a product (24) to be dimension-measured, and a product (2) in a direction substantially parallel to a rotation axis of the product (24).
4) a light source (26) for irradiating light so as to be partially shielded at the edge portion, and the product (24) for receiving light partially shielded at the edge portion of the product (24) A product size measuring device having a line sensor (30) arranged on the opposite side of the light source (26) along a radial direction of rotation at a position separated from the center of rotation of the product.