JP2009210413A - Anvil for hardness testing machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an anvil for a hardness testing machine for reducing the irregularity of measurement by attaching a sample support mechanism, which performs measurement even if a measuring person does not lay his hands, to a spot anvil. <P>SOLUTION: The anvil for the hardness testing machine is provided just under the hardness testing machine of a type, which presses an indenter to a sample to measure the hardness of the sample, in an up and down movable manner and provided with the spot anvil having a cylindrical body part and a shape wherein the sample placing surface smaller in diameter than the body part is protruded from the body part and a sample support stand threaded with the outer periphery of the body part of the spot anvil to be freely moved up and down with respect to the spot anvil. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a hardness tester of a type in which an indenter is pressed against a sample to measure the hardness of the sample, and in particular, a sample used in a hardness tester for measuring an indentation depth, such as a Rockwell hardness tester. Is related to the anvil where

The Rockwell hardness test is a metal hardness test method invented in the United States in 1919. Compared to other hardness testing methods, the measurement time is extremely short and the operation is simple, so it is currently most widely used around the world, mainly in various manufacturing industries. In addition, the test method is adopted in the industrial standards of each country such as ISO, JIS, ASTM, EN.
The feature of this test method is that it requires time-consuming work of measuring the size of the indentation with a microscope, whereas Rockwell hardness is obtained from the indentation depth of the indenter. This is because the calculation method of the hardness value is defined.

On the other hand, since the influence of elastic deformation of the tester or test piece (also referred to as a sample; the same shall apply hereinafter) appears significantly in the measurement of the indentation depth, the tester and the support ( Care must be taken, such as contacting the anvil) without any gaps.
Normally, the test piece is placed on a flat anvil that has been machined flat (commercially available ones with a diameter of about 60 to 70 mm). 5 is used, a sample anvil having a small contact surface 21 called a spot anvil 20 shown in FIG. 5 (which has a diameter of about 12 mm in many cases) is used so that the sample bottom surface and the anvil surface 2 are brought into close contact with each other. Recommended. However, since the sample is not stable when the contact surface becomes small, skills such as performing a test while holding the sample by hand are required. This also causes measurement errors, so there are many users who refrain from using spot anvils.

As the one using the spot anvil, the invention is such that the sample can be moved without being brought into contact with the spot anvil (refer to Patent Document 1) and the hardness is kept while the long sample is placed on the sample carrier. An invention (see Patent Document 2) that enables measurement is known.
JP-A-8-68738 JP-A-10-253513

In the conventional spot anvil, the measurement person performs the test while holding the test piece by hand, and thus the measurement results vary depending on the skill of the measurement person.
On the other hand, the applicant of the present application performs standard maintenance and supply of Rockwell hardness, and transfers a hardness standard value to a user using a metal block called “hardness reference piece” as a standard material. The bottom surface of the hardness reference piece is processed to be flat, but depending on the test conditions, a warping deformation may occur in the reference piece by applying a measuring force, and a gap may be formed between the anvil and the reference piece bottom. Under these conditions, since it is desirable to use a spot anvil, a spot anvil capable of performing a test with a small contact surface while stably supporting a sample has been desired.

  An object of the present invention is to provide an anvil for a hardness tester that can reduce variation in measurement by attaching a sample support mechanism to a spot anvil that can perform measurement without a measurer's hand. Is.

In order to achieve the above object, the anvil for a hardness tester according to the present invention is an anvil provided so as to be movable up and down directly under an indenter of a hardness tester of a type in which a hardness is measured by pressing an indenter on a sample. A spot anvil having a shape in which a cylindrical main body, a sample mounting surface having a smaller diameter than the main body protrudes from the main body, and a spot anvil that is screwed onto the outer periphery of the spot anvil so as to be vertically It is characterized by providing a movable sample support.
In addition, the anvil for a hardness tester according to the present invention can move up and down without tilting the support table, so that a guide surface is provided between the outer peripheral surface of the spot anvil body and the inner peripheral surface of the sample support table. It is characterized by forming.

The anvil for hardness tester of the present invention has the following excellent effects.
(1) At the user level, the accuracy of Rockwell hardness measurement is improved (variation is reduced), so the reliability of product quality assurance can be improved.
(2) At the calibration / testing institution and national standard level, the uncertainty can be reduced in the calibration of hardness reference pieces mainly made of non-ferrous metals such as Rockwell hardness B scale.

  Hereinafter, embodiments of an anvil for a hardness tester according to the present invention will be described in detail with reference to the drawings. However, the present invention is not construed as being limited thereto, and departs from the scope of the present invention. Insofar as various changes, modifications, and improvements can be made based on the knowledge of those skilled in the art.

   FIG. 1 is a perspective view showing a state where an anvil according to the present invention is mounted on a hardness tester. 2 is a front sectional view of an anvil for hardness testing machine according to the present invention, FIG. 3 is a front view of a spot anvil, and FIG. 4 is a front sectional view of a sample support.

  In FIG. 1, a nut 3 as a drive mechanism of an anvil 2 is rotatably attached to a main body 1 of a hardness tester. The anvil 2 is screwed into the nut 3 and can be moved in the vertical direction by rotation of the nut 3. A square screw member 4 as a base shaft is attached. The square screw member 4 is provided directly below the indenter 16 attached to the main body 1 of the hardness tester.

  As shown in FIG. 2, the anvil 2 includes a cylindrical main body 6, a spot anvil 5 having a shape in which a sample mounting surface 7 having a smaller diameter than the main body 6 protrudes upward from the main body 6, and the spot anvil 5. And a ring-shaped sample support base 8 that can be moved up and down with respect to the spot anvil 5 by screwing onto the outer periphery of the main body.

As shown in FIG. 3, the spot anvil 5 includes a large-diameter main body 6, a medium-diameter guide surface 13-1 continuously formed on the main body 6, a slightly small-diameter screw 11 formation surface, and a smallest diameter. The sample mounting surface 7 and a lower cylindrical portion 9 having a small diameter formed continuously on the lower side of the main body 6 are formed.
In this specification, the main part of the spot anvil refers to the large-diameter main body 6, the medium-diameter guide surface 13-1 formed continuously above the main body 6, and the slightly-small-diameter screw 11 formation surface. ing.
A small-diameter lower cylindrical portion 9 projecting downward from the main body 6 of the spot anvil 5 is fitted into the fitting hole 10 of the square screw member 4 so that the spot anvil 5 is supported by the square screw member 4.

  As shown in FIG. 4, the sample support 8 has a ring shape, and a screw 12 forming surface that is screwed to the screw 11 of the spot anvil 5 is formed on the inner peripheral upper part, and the spot anvil 5 is formed on the inner peripheral lower part. A guide surface 13-2 that engages with the guide surface 13-1 is formed. The sample support 8 is movable up and down with respect to the spot anvil 5 by being screwed to the spot anvil 5 with screws 11 and 12. Further, a plurality of female screw holes 14 are provided through the outer peripheral surface at a position orthogonal to the guide surface 13-2, and a fixing screw 15 (see FIG. 1) is screwed into the female screw hole 14.

Generally, since the anvil of the Rockwell hardness tester should not be deformed by the measuring force (100 kgf on B scale), the spot anvil 5 is made of a material having sufficient hardness such as hardened steel. In the prototype, tool steel SKS3 was quenched and tempered.
On the other hand, since no test force acts on the sample support base 8, no mechanical strength is required. The prototype was made of stainless steel SUS316.

As will be described later, the screw 11 formed on the outer periphery of the upper portion of the main body 6 of the spot anvil 5 uses a fine pitch fine screw in order to precisely set the step between the sample mounting surface 7 and the sample support base 8. When the sample support base 8 moves with respect to the spot anvil 5, in order to prevent the upper surface of the sample support base 8 from being inclined due to rattling, the space between the spot anvil 5 and the sample support base 8 is shown in FIG. Thus, the guide surface 13 is set. The guide surface 13 includes the guide surface 13-1 of the spot anvil 5 and the guide surface 13-2 of the sample support base 8.
By setting the fit between the guide surfaces 13-1 and 13-2 to the necessary minimum gap, the sample support 8 is prevented from being inclined while maintaining smooth rotation. In the prototype, since the guide surface has a clearance fit of 10 to 59 μm with respect to the guide surface diameter of 60 mm and the length of the guide surface 13 is about 10 mm, the tolerance of the inclination of the sample support 8 is 3 ′ to 20 ′. .

The height of the sample support table 8 is adjusted so that the upper surface of the sample support table 8 and the sample mounting surface 7 of the spot anvil 5 coincide with each other. In this state, the sample support surface 8 and the sample mounting surface 7 of the spot anvil 5 are moved. Polish at the same time. The engagement positions of the screws 11 and 12 at this time are marked 13 on the outer peripheral surface of the main body 6 and the outer peripheral surface of the sample support 8 of the spot anvil 5 (see FIG. 1), and the sample mounting surface 7 of the spot anvil 5 and the sample A reference position where the step on the upper surface of the support base 8 is zero is used.
When the hardness test is performed in a state where the upper surface of the sample support 8 and the sample mounting surface 7 of the spot anvil 5 are aligned, the fixing screw 15 is screwed into the female screw hole 14 at the reference position, and the tip of the fixing screw 15 is spotted. The sample support 8 is pushed into the guide surface 13-1 of the anvil 5 and fixed to the spot anvil 5.

When using the spot anvil 5 alone without using the sample support base 8, the sample mounting surface 7 of the spot anvil 5 must protrude from the upper surface of the sample support base 8. By shifting, the sample mounting surface 7 of the spot anvil 5 is relatively projected. In this state, the fixing screw 15 is screwed to fix the sample support 8 to the spot anvil 5.
The protrusion amount (the step between the sample mounting surface 7 of the spot anvil 5 and the upper surface of the sample support base 8) can be obtained from the rotation angle of the sample support base 8 with respect to the spot anvil 5 and the pitch of the screws 11 and 12. Therefore, it is possible to set a minute step of about several tens of μm. When the level difference is small in this way, the change in the posture of the sample between the state where the sample is placed on the sample support base 8 and the state where the test force is loaded is small, so it is appropriate even if the sample is not held by hand. A hardness test can be performed.

  A hardness tester of a type that measures the hardness of a sample by pressing an indenter on the sample. Particularly, a hardness tester that measures the indentation depth, for example, a Rockwell hardness tester is used in the manufacturing industry in the metal and mechanical fields. It is often used for purposes such as product inspection and quality assurance. According to the present invention, since more accurate measurement can be easily performed, the practicality as a product is high. In addition, there is a high need for businesses that calibrate hardness testers and hardness reference pieces because the present invention directly contributes to the improvement of the maximum measurement capability.

It is a perspective view which shows the state with which the anvil which concerns on this invention was mounted | worn with the hardness tester. It is front sectional drawing of the anvil which concerns on this invention. It is a front view of the spot anvil which concerns on this invention. It is front sectional drawing of the sample support stand which concerns on this invention. It is a perspective view which shows the conventional spot anvil.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Main body of hardness tester 2 Anvil 3 Nut 4 Square screw member 5 Spot anvil 6 Main body 7 Sample mounting surface 8 Sample support stand 9 Lower cylindrical part 10 Fitting hole 11 Screw 12 Screw 13 Guide surface 14 Female screw hole 15 Fixing screw 16 Indenter

Claims (2)

  In an anvil that can be moved up and down just below the indenter of a hardness tester that measures the hardness of the sample by pressing the indenter against the sample, a cylindrical main body and a sample mounting with a smaller diameter than the main body A hardness tester comprising: a spot anvil having a shape with a surface protruding from a main body portion; and a sample support base that is screwed to the outer periphery of the main body portion of the spot anvil and is movable up and down with respect to the spot anvil. For anvil.   The guide surface is formed between the outer peripheral surface of the main body portion of the spot anvil and the inner peripheral surface of the sample support base in order to enable vertical movement without tilting the support base. Anvil for hardness testing machine.

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