Method for centering grinding wheel in thread grinder and measurement device for centering

Patent metadata

Field	Value
Publication number	US-9707649-B2
Application number	US-201314439500-A
Country	US
Kind code	B2
Filing date	Oct 25, 2013
Priority date	Oct 31, 2012
Publication date	Jul 18, 2017
Grant date	Jul 18, 2017

Abstract

In a thread grinder which grinds a thread grove on an inner surface of a workpiece while a rotation axis of a grinding wheel shaft is inclined with respect to an axis of a main shaft, a centering master which has a cylindrical outer surface is mounted to the main shaft. A measuring unit including two measuring instruments such that probes can contact two edges of a grinding wheel is mounted to the centering master. The origins of the measuring instruments are set by the probes contacting the cylindrical outer surface of the centering master. The measuring unit is moved in the axial direction of the centering master to bring the probes of the two measuring instruments into contact with the edges of the grinding wheel, respectively. The position of the grinding wheel shaft is adjusted such that measured values obtained by measuring instruments become same.

First claim

The invention clamed is:

1. A method for centering a grinding wheel in a thread grinder which includes: a grinding wheel shaft; a grinding wheel attached to the grinding wheel shaft; and a main shaft which faces the grinding wheel shaft and to which a workpiece having a cylindrical inner surface to be ground with a thread groove is attached, wherein a rotation axis of the grinding wheel shaft is inclined with respect to an axis of the main shaft in accordance with a lead angle of the thread groove, the method comprising:
mounting a centering master having a cylindrical outer surface to the main shaft such that a center axis of the centering master is matched with the axis of the main shaft;
mounting a measuring unit to the centering master to be movable in an axis direction of the centering master, the measuring unit including: a first measuring instrument having a first probe configured to contact one edge part of the grinding wheel in an orthogonal direction orthogonal to the axis direction of the centering master; and a second measuring instrument having a second probe configured to contact another edge part of the grinding wheel opposite to the one edge part in the orthogonal direction;
setting origins of the first and second measuring instruments by bringing the first and second probes into contact with the cylindrical outer surface of the centering master;
moving the measuring unit in the axis direction of the centering master to thereby bring the first and second probes into contact with the respective edge parts of the grinding wheel in the orthogonal direction; and

centering a center of the grinding wheel with respect to the axis of the main shaft by adjusting a position of the grinding wheel shaft such that a measured value obtained based on the origin of the first measuring instrument and a measured value obtained based on the origin of the second measuring instrument become same.

2. The method according to claim 1 , further comprising:
adjusting positions of the first and second measuring instruments such that the first probe contacts one edge part of the grinding wheel in a direction orthogonal to an inclined direction of the grinding wheel and the second probe contacts another edge part of the grinding wheel opposite to the one edge part in the direction orthogonal to the inclined direction of the grinding wheel, at a state where the measuring unit is rotated by 90° about the centering master from a state where the centering of the grinding wheel is performed;
moving the first and second measuring instruments of which the origins are set using the centering master, in the axis direction of the centering master, to thereby bring the first and second probes into contact with the two edge parts of the grinding wheel in the direction orthogonal to the inclined direction of the grinding wheel; and
centering the center of the grinding wheel with respect to the axis of the main shaft by adjusting the position of the grinding wheel shaft such that a measured value obtained based on the origin of the first measuring instrument and a measured value obtained based on the origin of the second measuring instrument become same.

3. A measurement device for centering a grinding wheel in a thread grinder including: a grinding wheel shaft, a grinding wheel attached to the grinding wheel shaft; and a main shaft which faces the grinding wheel shaft and to which a workpiece having a cylindrical inner surface to be ground with a thread groove is attached, wherein a rotation axis of the grinding wheel shaft is inclined with respect to an axis of the main shaft in accordance with a lead angle of the thread groove, the measurement device comprising:
a centering master which has a cylindrical outer surface and is configured to be mounted to the main shaft such that a center axis of the centering master is matched with the axis of the main shaft; and
a measuring unit which includes a cylindrical body configured to be mounted to the cylindrical outer surface of the centering master to be movable in an axis direction and a circumferential direction of the centering master, a first measuring instrument having a first probe configured to contact one edge part of the grinding wheel in an orthogonal direction orthogonal to the axis direction of the centering master, and a second measuring instrument having a second probe configured to contact another edge part of the grinding wheel opposite to the one edge part in the orthogonal direction, and which is configured to measure a displacement of the grinding wheel in the orthogonal direction by the first and second measuring instruments.

4. The measurement device according to claim 3 ,
wherein at least one of the first and second measuring instruments is configured to be moveable relative to the cylindrical body in the axis direction of the centering master.

Assignees

• Nsk Ltd

Inventors

• Igarashi Kiyoshi

Classifications

• B23G1/38

  with grinding discs guided along the workpiece in accordance with the pitch of the required thread · CPC title

• B23G1/48

  for guiding the threading tools · CPC title

• B24B49/10

  involving electrical means (B24B49/02, B24B49/08 take precedence) · CPC title

• G01B2210/44

  with detectors on both sides of the object to be measured · CPC title

• B23P19/10 Primary

  Aligning parts to be fitted together · CPC title