Hardness tester

Patent metadata

Field	Value
Publication number	US-9341554-B2
Application number	US-201414193403-A
Country	US
Kind code	B2
Filing date	Feb 28, 2014
Priority date	Mar 6, 2013
Publication date	May 17, 2016
Grant date	May 17, 2016

Abstract

A hardness tester has a test force applier generating a test force using an electromagnetic force generated by supplying a current to a drive coil provided in a magnetic field and applies the test force to an indenter to press the indenter into a surface of a sample; a temperature detector detecting a temperature of the test force applier; and a test force corrector correcting the test force generated from the test force applier based on the temperature detected by the temperature detector.

First claim

What is claimed is:

1. A hardness tester for measuring hardness of a sample by applying a test force to a surface of the sample with an indenter to form an indentation and by measuring a depth of indentation of the indenter at a time of forming the indentation, the hardness tester comprising:
a test force applier configured to generate the test force using an electromagnetic force generated by supplying a current to a drive coil provided in a magnetic field, the test force applier further configured to apply the test force to the indenter to press the indenter into the surface of the sample;
a temperature detector configured to detect a temperature of the test force applier; and
a test force corrector configured to correct the test force generated from the test force applier by a predetermined value, based on the temperature detected by the temperature detector.

2. The hardness tester according to claim 1 , further comprising:
a test force measurer configured to measure the test force applied by the indenter to the sample placed on an upper surface; and
a memory configured to store a test force correction table generated based on the test force generated by the test force applier, a measurement value of the test force measured by the test force measurer, and the temperature detected by the temperature detector, wherein the test force corrector is further configured to correct the test force generated by the test force applier based on the test force correction table stored in the memory.

3. The hardness tester according to claim 2 , further comprising:
a lift configured to move the test force measurer in an up-down direction;
an ingress amount detector configured to detect an amount of ingress of the indenter pressed into the surface of the sample by the test force applier;
a determiner configured to cause the lift to adjust a height of a position where the indenter comes into contact with the sample based on the amount of ingress of the indenter detected by the ingress amount detector after the indenter is pressed into the surface of the sample by the test force applier, the determiner further configured to determine whether the height of the position where the indenter comes into contact with the sample is at a predetermined reference position;
a measurement controller configured to cause the test force measurer to measure the test force applied to the sample, the measurement controller further configured to cause the temperature detector to detect the temperature of the test force applier when the determiner determines that the height is at the predetermined reference position; and
a table generator configured to generate the test force correction table based on a measurement value of the test force and the detected temperature under control of the measurement controller.

Assignees

• Mitutoyo Corp

Inventors

• Tsujii Masaharu
• Mori Satoko

Classifications

• G01N2203/0222

  Temperature · CPC title

• G01N2203/0078

  using indentation · CPC title

• G01N3/42 Primary

  by performing impressions under a steady load by indentors, e.g. sphere, pyramid (G01N3/54 takes precedence) · CPC title