JPH02176404A - Curvature-radius measuring device - Google Patents

Abstract

PURPOSE:To make it possible to measure a curvature even for a material to be measured having a partial spherical body readily and accurately by bringing a material to be measured into contact with the main body of a measuring part, wherein a conical recess part is formed at the upper part, from the upper side, and inserting a dial gage from the lower side. CONSTITUTION:A conical recess part 1b having the angle of 60 degrees is formed at an upper end part 1b of a main body 1 of a measuring part. A dial gate 2 as a length measuring means is arranged in a lower measuring hole 1d through a lower end part 1c. When the diameter of a curvature is measured, at first a reference spherical body whose curvature is known is inserted. The distance from a conical imaginary top to the spherical body is measured with the gage 2. Then, a material to be measured is inserted into the recess part 1b, and the distance from the imaginary top is measured with the gage 2 by the same way. The radius of the curvature of the material to be measured is obtained by a specified computing equation from the difference between said distances. Therefore, the curvature of a rod shaped body whose tip has the spherical shape even if it is not the spherical body can be readily measured.

Description

Detailed Description of the Invention [Objective of the Invention] (Industrial Application Field) This invention relates to a radius of curvature a of a structure formed by a sphere, a cylinder, or a partial sphere or cylinder.
Regarding lJ constant.

(Prior art) As a method for determining the radius of curvature of a sphere or cylinder, the outer shape of the object is measured by sandwiching the object, such as a caliper or an outer micrometer, between two parallel 1ill constant surfaces. A diameter method is generally used in which the diameter of a sphere or cylinder to be measured is determined by n1 using an al determiner, and the radius of curvature is determined from the obtained diameter value. Also, such two parallel measurement surfaces are
In order to eliminate the drawback that the measurement position of the diameter method using the 11P1 measuring device tends to deviate from the virtual origin, the 11 or 1
The radius of curvature has also been similarly determined using a measuring device in which one of the fixed surfaces is composed of two planes adjacent at right angles.

However, these diameter methods are effective for determining the radius of curvature of a perfect sphere or cylinder, but they cannot be used for structures where one end of a rod is made up of a hemisphere or for plates. Structures such as one end of which is made up of a semi-cylindrical body, etc.
When trying to find the radius of curvature of a structure whose curved surface is formed by part of a sphere or cylinder, it is impossible to measure the radius of curvature because the virtual origin cannot be sandwiched between the structures.

Therefore, ll? as shown below? A ternary method is used.

■ A method of measuring the shape of a spherical or cylindrical surface by tracing the surface of the object to be measured multiple times with a stylus, etc., and calculating the radius of curvature from a circle calculation formula by calculating this ill constant value (hereinafter referred to as tracing). ).

■ A method of determining the coordinates of multiple locations on the surface of a constant object using a probe, etc., and calculating the radius of curvature from a circle calculation formula by calculating these coordinate values (hereinafter referred to as the probe method).

(Problem to be Solved by the Invention) However, even if the above-mentioned tracing method or probe method is used, in the case of an imperfect spherical or cylindrical surface,
Since a complete circle or sphere is calculated from the measurement of a partial circle or sphere, and the radius of curvature is determined from this calculated value, there is a problem that slight measurement errors are amplified and errors tend to occur in the radius of curvature obtained. . In particular, in the case of the probe method, the radius of curvature is calculated from the coordinates of a plurality of points, so if an error occurs in the i'llj constant even at the - point, the i'll11 constant accuracy will drop significantly. Furthermore, when the surface of the object to be measured has a large surface roughness, errors are likely to occur particularly in the measurement values obtained by the tracing method, resulting in a significant decrease in measurement accuracy.

In addition, if there is some distortion in the spherical or circular shape of the object to be measured, the calculation will be performed as an average spherical or circular shape, so some parts may not match the actual shape. Put it away. Since the radius of curvature is determined by averaging in this way, it is of course impossible to determine the partial radius of curvature of a distorted sphere or circle.

Furthermore, curvature radius measurement devices that apply the trace method or probe method require calculation functions and have a complicated configuration of the 11-1 constant part, so the device itself is expensive and its operation is complicated. Therefore, there are also drawbacks such as high fixed costs for all.

This invention was made to address the problems of the prior art, and it is possible to improve the quality and precision even in the curved surface of a structure where the curved surface is formed by a part of a sphere or cylinder. It is an object of the present invention to provide a radius of curvature #1 determiner that can accurately determine the radius of curvature and can also measure the radius of curvature of each part of a partially distorted spherical or cylindrical surface.

[Structure of the invention]

(Means for Solving the Problem) That is, the radius of curvature n1 determiner of the present invention includes a measuring section main body, and a conical or V shape having a predetermined angle, the inner surface of which is provided at one end of the measuring section main body and whose inner surface becomes the measuring surface. By contacting a groove-shaped recess, a measurement hole bored from the other end of the measurement unit main body so as to communicate with the recess from the top direction, and an object to be measured placed in contact with the recess. Measure the radius of curvature a
-1 measuring means.

(Function) In the curvature radius measuring device of the present invention, for example, first, a reference sphere or a reference cylindrical body with a known radius of curvature is placed in contact with the conical or V-groove recess of the measuring part body, and the length measuring means is used to measure the reference sphere or the reference cylinder. Measure the distance from the virtual apex of the conical or V-groove-shaped recess at the tip position. Next, all the curved surfaces of the objects to be measured are placed in contact with the conical or V-groove recesses, and the distances of the tip positions of the curved surfaces from the virtual apex of the conical or V-groove recesses are determined. Then, the radius of curvature of the curved surface of the object 4-1 can be determined from the difference in distance from these virtual vertices.

Therefore, as long as the curved surface of the object to be measured comes into contact with the conical or V-groove recess and is fixed as a surface, it is possible to accurately measure the radius of curvature of even a partially spherical or cylindrical object.

Furthermore, if the curved surface of the object to be measured has partially different radii of curvature, it can be calculated as a change in the difference in distance from the virtual vertex.

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

FIG. 1 is a diagram showing a radius of curvature measuring device for a sphere according to an embodiment of the present invention. In the figure, reference numeral 1 denotes a cylindrical measuring section body made of a material with excellent wear resistance, such as cemented carbide or ceramic material. This ΔP1
A conical recess 1b having a predetermined angle with respect to the surface thereof is bored in one end 1a of the main body 1, and the inner surface of this conical recess 1b serves as a measurement surface. In addition, a measurement hole 1d is formed in the measurement section main body 1, and the measurement hole 1d communicates from the other end 1c to the conical recess 1b from the top direction. It has an inverted conical shape with the conical recess 1b.

For example, a dial gauge 2 is arranged as a length measuring means in the measurement hole 1d of the a1 fixed part main body 1 from the other end 1c side of the measuring part main body 1. The sleeve 2C is inserted into the measurement hole ld so that the measured probe 2b reaches the inside of the conical recess 1b.
A screw groove 1 inserted into the measuring section main body 1 and provided on the side surface of the measuring section main body 1
It is fixed by a fixing screw 3 screwed into e.

This dial gauge 2 is a normal dial gauge,
The stroke of the spindle 2a is measured with a pointer 2d by bringing the measuring stylus 2b into contact with the object to be measured, and zeroing is possible with a rotatable scale plate 2e.

Further, on the outer periphery of the constant part main body 1 of 11-1, a conical recess 1b is provided.
A support 4 for setting the measurement range of the object to be measured 5 whose radius of curvature is to be measured is arranged to protrude from one end 1a of the Δ-1 fixed part main body 1 in which the conical recess 1b is formed. The support 4 is also fixed to the measuring section main body 1 by a fixing screw (not shown).

Note that this support 4 is not directly involved in measuring the radius of curvature, and is unnecessary when simply measuring the radius of curvature.

Next, the measurement principle of the radius of curvature measuring device of this embodiment having the above-mentioned configuration will be explained with reference to FIG.

In the figure, 6 is a sphere serving as a reference body with a known radius of curvature, and 7 is a sphere serving as a fixed object 31, and these are each fixed in contact with the inner surface of the conical recess 1b of the measuring section main body 1. In addition, the radius of the sphere 6 is 1, the radius of the measured sphere 7 is rl, the top angle of the conical recess 1b is θ, and the top angle θ from the assumed apex 0 of the conical recess 1b to the surface of the reference sphere 6 is 2. The distance on the equal dividing line is β1, and the measured sphere 7
Let the distance to the surface be 12.

Here, from the assumed apex O of the conical recess 1b to the measured sphere 7
Since the distance 11 to the center 02 of can be expressed as 1-2 sin (θ/2), J22 becomes 112- +H-rl-rl-rz sln (θ/2). The radius of curvature "2" of the measured sphere 7 is determined from the ratio of rl and 12 as rl:!z-r2:
rl-rzsln (θ/2) "2 'rl""2 ・ β2 "2 sin (θ/2) "2 "2 ・ (2 "2 (1-sin (θ12)) sin (θ/2) sin ( θ/2) Here, if we set bu1-J2z-Δβ, sin (θ/
2) Also, since 11 is similarly expressed as β1-rl sin (θ/2), “1! Since θ is known and Δk is the actual value measured by the dial gauge 2 inserted and fixed in the 4-1 fixed part main body 1, ``2'' can be obtained. Then, r2 = 12 J2 + - 8β, and the value of the radius r2 of the sphere to be measured 7 can be directly read from the actual measured value of 8β as a scale of l:l, further shortening the measurement time. becomes possible.

In actual measurement, as explained above, if the radius of curvature r1 of the reference sphere 6 is larger than the radius of curvature "2" of the sphere to be measured 7, then the dial gauge 2, which is omitted in FIG. The pointer 2d is moved to the minus side of the scale plate 28 by the movement of the dial gauge 2, and the reference sphere 6 is inserted and fixed into the conical recess 1b, and the position where the Δ-1 constant 2b of the dial gauge 2 touches the reference sphere 6 is determined. Adjust the scale plate 2e so that the radius of the reference sphere 6 becomes a value of 1.
By setting , when the target a-1 fixed sphere 7 is inserted and fixed into the conical recess 1b, the pointer 2 of the dial gauge 2
The value indicated by d can be directly read as the value of 2, which is the radius of curvature of the fixed sphere 7 of the subject 71-1.

Next, a measurement method using the curvature radius measuring instrument having the above configuration will be explained. In this example, a structure in which one end of a rod-like body in the longitudinal direction is formed into a hemispherical surface will be used as the object J1 fixed object 5.

First, as shown in FIG. 3(a), set the reference sphere 6 in the conical recess 1b of the measuring section main body 1, and apply some pressure so that the reference sphere 6 is fixed in contact with the inner surface of the conical recess 1b. (indicated by arrow A in the figure), and set the position of the measuring tip 2b of the dial gauge 2. In this state, the value pointed by the pointer 2d of the dial gauge 2 is the radius of curvature of the reference sphere 6.
The scale plate 2e is set so that the value is 1.

Next, after removing the reference sphere 6, the spherical part 5a of the object a-1 fixed object 5 is similarly set in the conical recess 1, and the pointer 2d of the dial gauge 2 is The radius of curvature r2 of the spherical portion 5a of the fixed object 5 is measured.

Furthermore, by moving the object to be measured 5 while maintaining the state in which the spherical portion 5a of the object to be measured 5 is in contact with the inner surface of the conical recess 1b, the radius of curvature of the minute portion of the spherical portion 5a is “2”. The value of can be determined, and for example, the machining accuracy of the spherical portion 5a can be determined.

Furthermore, for example, if the tolerance range of the dimensional accuracy of the radius of curvature of the spherical part 5a of the fixed object 5 is limited, the height of the support 4 can be set in advance in accordance with the dimensional accuracy to facilitate measurement. It becomes possible to limit the range, and the guaranteed range can be easily defined when, for example, measurements are made for quality assurance.

Using this method, the 11-1 constant of the radius of curvature of the spherical portion 5a of the all constant object 5 whose one end is a hemispherical surface was found to be approximately 0.5 per piece.
While it was possible to perform measurements in a short time of 1 minute, the conventional tracing method took about 30 to 60 minutes (measurement time varies greatly depending on the skill level of the operator), and the probe method took about 5 minutes.
The measurement time was 10 minutes to 10 minutes, and the time required to measure the radius of curvature could be significantly shortened. In addition, in the conventional tracing method and probe method, the radius of curvature is determined theoretically based on the constant result, so it was not possible to determine the radius of curvature in a minute part of the spherical surface. According to the radius of curvature D1 determiner, it was also possible to determine the irregularly shaped state of the spherical surface by changing the abutment position of the object 5 against the conical recess 1b and performing measurements multiple times. Since the measurement accuracy can also be kept within the measurement error of the dial gauge 2, a highly accurate Δ-1 constant can be achieved.

As described above, according to the radius of curvature ΔP1 determiner for spheres of this embodiment, the radius of curvature can be measured accurately in a short period of time even for objects to be measured whose curved surfaces are made up of partial spheres, and It is also possible to determine the abnormal shape of a spherical surface.

Alternatively, as shown in FIG. 4, an a11 constant body 1 may be used in which the inner surface of a conical recess 1b is provided with slit-like protrusions 11 at positions dividing the conical shape into three equal parts.

As described above, by providing the slit-like protrusion 11 in the conical recess 1b, the contact position with respect to the slit-like protrusion 11 changes when the measurement spherical surface of the object to be measured 5 has an irregular shape in the direction parallel to the measurement surface. , the change can be read as a change in the radius of curvature of the object 5 to be measured ``2'', making it possible to more accurately determine the spherical surface of the object 5 to be measured.

Next, other embodiments of the invention will be described.

FIG. 5 is a diagram showing a Δ-1 constant part main body 21 of a curvature radius measuring device for a cylindrical body according to another embodiment of the present invention.

This measuring section main body 21 has one end i? A V-groove 21b having a predetermined angle with respect to j21a is formed, and the inner surface of this V-groove 21b serves as a measurement surface. As in the previous embodiment, a measurement hole 21d communicating from the top of the V-groove 21b is formed at the other end 21c.

Similarly to the above embodiment, a dial gauge (not shown), for example, is fixed to the a-1 fixed hole 21d, thereby constructing a radius of curvature -11 for a cylindrical body.

According to the radius of curvature measuring device of this embodiment, it is possible to determine the radius of curvature of a curved surface such as a structure in which one end of a cylindrical body or a plate-like body is constituted by a partial cylindrical surface. The measurement principle is the same as that of the above-mentioned embodiment, and the measurement is carried out by placing the cylindrical surface of the object a or 1 in contact with the longitudinal direction of the V-groove 21b. It can be carried out.

In addition, in each of the above-mentioned embodiments, an example was explained in which a dial gauge was used as a length measuring means, but the present invention is not limited to this, and various types may be used depending on the measurement conditions etc. Is possible.

[Effects of the Invention] As explained above, according to the curvature radius measuring device of the present invention, it is possible to measure the radius of curvature even in the case of a 71-1 constant object, for example, where a spherical surface or cylindrical surface is composed of partial spheres or cylinders. , it is possible to accurately determine the radius of curvature of 7t-1 in a short time, and it is also possible to determine the irregular shape of the curved surface. Furthermore, since the n1 constant is obtained by comparison with the reference body, measurement accuracy can also be maintained.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing a radius of curvature n1 determiner according to an embodiment of the present invention, FIG. 2 is a diagram showing its measurement principle, and FIG. 3 is an explanation of how the radius of curvature υ1 determiner shown in FIG. 1 is used. Figure for, 4th
This figure shows a modification of the conical recess in the radius of curvature measuring device shown in FIG. 1, and FIG. 5 shows the main part of another embodiment of the invention. 1.21...Measurement part body, 1b...Conical recess, ld, 21d...Measurement hole, 2...
...Dial gauge, 2b...Measuring head, 5.
...-Object to be measured, 6...Reference sphere, 11.
...Slit-shaped convex part, 21b... V-groove-shaped concave part. Applicant Toshiba Corporation Patent Attorney Sasa Suyama - Figure 1

Claims (2)

[Claims] (1) A measuring part main body, a conical or V-groove recessed part provided at one end of the measuring part main body and having a predetermined angle whose inner surface becomes the measuring surface, and a concave part that communicates with this recessed part from the top direction. A curvature characterized by comprising: a measurement hole drilled from the other end of the measurement unit main body; and a measurement means for measuring a radius of curvature by contacting an object to be measured that is placed in contact with the recess. Radius measuring instrument. (2) The angle of the conical or V-groove recess is 60°.
The radius of curvature measuring instrument according to claim 1, characterized in that: