Workpiece centering apparatus and workpiece centering method

• US 8,601,703 B2
• Filed: 12/08/2011
• Issued: 12/10/2013
• Est. Priority Date: 01/11/2011
• Status: Expired due to Fees

• Current Assignee: Jtekt Corporation (Toyota Motor Corporation)
• Original Assignee: Jtekt Corporation (Toyota Motor Corporation)
• Inventors: Makiuchi, Akira, Kato, Ikuya, Somyo, Yoshihiro, Goto, Keita, Yabuki, Kenichi
• Primary Examiner(s): FULTON, CHRISTOPHER W
• Application Number:
  US13/314,356
• Publication Number:
  US 20120174424A1
• Time in Patent Office: 733 Days
• Field of Search: 335/20, 335/49, 335/50, 335/51, 335/53, 335/54, 335/55
• US Class Current: 33/520
• CPC Class Codes: B23Q 17/2291 for adjusting the workpiece relative to the holder thereof
• CPC Class Codes: B23Q 3/183 Centering devices

Abstract

The positions of at least three points, which are circumferentially, and equiangularly, offset from each other, of a peripheral face of a workpiece set on a rotary table are measured using a position detection probe. The amount of runout of the axis of the workpiece and a phase position of the workpiece, at which the runout amount is largest, are calculated from the measured positions of the equiangularly offset points. The rotary table is turned to set the largest runout phase position of the workpiece in a position opposed to a workpiece contact of a centering apparatus. The relative positions of the workpiece and a position detection block are calculated using the position detection probe. The workpiece is centered by moving a centering shaft member of the centering apparatus such that the workpiece contact pushes the workpiece by a distance corresponding to the runout amount.

Claims

1. A centering apparatus that centers a columnar or cylindrical workpiece set on a rotary table, comprising:

a centering shaft member that is movable in a direction orthogonal to a rotation axis of the rotary table;

a workpiece contact that is provided at the centering shaft member, and is adapted to come into contact with, as the contact shaft member moves, a peripheral face of the workpiece and push the workpiece in a radial direction of the workpiece;

a position detection block that is provided at the centering shaft member;

a position detection probe that is movable in a direction orthogonal to the rotation axis of the rotary table, and is adapted to come into contact with the workpiece and the position detection block; and

a centering controller that controls centering of the workpiece through control of the centering shaft member and the position detection probe, wherein

the centering controller comprises;

workpiece peripheral face position measuring means for bringing the position detection probe into contact with at least three points of the peripheral face of the workpiece, which are offset circumferentially from each other, and measuring each contact position between the position detection probe and the workpiece, with rotation of the rotary table stopped;

runout calculating means for calculating an amount of runout of an axis of the workpiece and a largest runout phase position that is a phase position of the workpiece, at which the runout amount is largest, based on the measured contact positions;

block position measuring means for bringing the position detection probe into contact with the position detection block and measuring a position of the position detection block;

phase position indexing means for turning the rotary table so as to set the largest runout phase position of the workpiece in a position opposed to the workpiece contact;

relative position deriving means for deriving relative positions of the workpiece and the workpiece contact in a state where the largest runout phase position of the workpiece is in the position opposed to the workpiece contact as a result of turning of the rotary table, based on the contact positions measured by the workpiece peripheral face position measuring means and the position of the position detection block measured by the block position measuring means; and

pushing means for, after the phase position indexing means sets the largest runout phase position of the workpiece in the position opposed to the workpiece contact, centering the workpiece by moving the centering shaft member based on the relative positions of the workpiece and the workpiece contact such that the workpiece contact pushes the workpiece by a distance corresponding to the runout amount.

2. The centering apparatus according to claim 1, wherein the at least three points of the peripheral face of the workpiece are equiangularly offset from each other.

3. The centering apparatus according to claim 1, wherein the position detection block has a contact face extending in a direction orthogonal to the direction in which the position detection probe moves.

4. The centering apparatus according to claim 1, wherein the centering apparatus is mounted on a bed on which the rotary table is provided.

5. The centering apparatus according to claim 1, wherein the position detection probe is moved to and kept in a position that is on a side opposite, across the workpiece, to where the workpiece contact is present and that is a distance corresponding to the runout amount away from the peripheral face of the workpiece, and the workpiece contact is made to push the workpiece until the peripheral face of the workpiece contacts the position detection probe.

6. The centering apparatus according to claim 1, wherein:

the centering shaft member is arranged so as to be inclined by a predetermined angle with respect to the direction in which the position detection probe moves; and

a face of the position detection block, which comes into contact with the position detection probe, is orthogonal to the direction in which the position detection probe moves.

7. A centering method implemented by a centering apparatus that centers a columnar or cylindrical workpiece set on a rotary table, comprising:

a centering shaft member that is movable in a direction orthogonal to a rotation axis of the rotary table;

a workpiece contact that is provided at the centering shaft member, and is adapted to come into contact with, as the contact shaft member moves, a peripheral face of the workpiece and push the workpiece in a radial direction of the workpiece;

a position detection block that is provided at the centering shaft member;

a position detection probe that is movable in a direction orthogonal to the rotation axis of the rotary table, and is adapted to come into contact with the workpiece and the position detection block; and

a centering controller that controls centering of the workpiece through control of the centering shaft member and the position detection probe, the centering method comprising;

workpiece peripheral face position measuring step of bringing the position detection probe into contact with at least three points of the peripheral face of the workpiece, which are offset circumferentially from each other, and measuring each contact position between the position detection probe and the workpiece, with rotation of the rotary table stopped;

runout calculating step of calculating an amount of runout of an axis of the workpiece and a largest runout phase position that is a phase position of the workpiece, at which the runout amount is largest, based on the measured contact positions;

block position measuring step of bringing the position detection probe into contact with the position detection block and measuring a position of the position detection block;

phase position indexing step of turning the rotary table so as to set the largest runout phase position of the workpiece in a position opposed to the workpiece contact;

relative position deriving step of deriving relative positions of the workpiece and the workpiece contact in a state where the largest runout phase position of the workpiece is in the position opposed to the workpiece contact as a result of turning of the rotary table, based on the contact positions measured in the workpiece peripheral face position measuring step and the position of the position detection block measured in the block position measuring step; and

pushing step of, after setting the largest runout phase position of the workpiece in the position opposed to the workpiece contact in the phase position indexing step, centering the workpiece by moving the centering shaft member based on the relative positions of the workpiece and the workpiece contact such that the workpiece contact pushes the workpiece by a distance corresponding to the runout amount.