# US 8,464,644 B2 · Rotary table assembly

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- Number: US 8,464,644 B2
- Document ID: US8464644B2
- Status: Granted
- Kind: B2
- Application number: 13/288,262
- Filed: 2011-11-03
- Published: 2013-02-28
- Granted: 2013-06-18
- Earliest claimed: 2011-08-26
- Assignees: Nikken Kosakusho Works Ltd.
- Applicants: Kazuhisa Fujimoto
- Inventors: Kazuhisa Fujimoto
- Web page: https://patentgrep.com/patent/US8464644B2

## CPC

- B23Q 1/0027: {between moving parts between which an uninterrupted energy-transfer connection is maintained}
- B23Q 2220/004: Rotary tables
- Y10T 74/14: Rotary member or shaft indexing, e.g., tool or work turret
- B23Q: DETAILS, COMPONENTS, OR ACCESSORIES FOR MACHINE TOOLS, e.g. ARRANGEMENTS FOR COPYING OR CONTROLLING (tools of the kind used in lathes or boring machines B23B27/00); MACHINE TOOLS IN GENERAL CHARACTERISED BY THE CONSTRUCTION OF PARTICULAR DETAILS OR COMPONENTS; COMBINATIONS OR ASSOCIATIONS OF METAL-WORKING MACHINES, NOT DIRECTED TO A PARTICULAR RESULT
- Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION

## Abstract

A rotary table assembly is configured to prevent torsional deformation of a sealing member on an outer peripheral surface of a rotary joint. The rotary joint has a distributor and a center shaft, which includes two hollow cylindrical center shafts respectively inserted into a through hole from opposite front and back surface sides of a rotatable table. The sealing member makes contact with the outer peripheral surface of the hollow cylindrical center shaft positioned near the front surface of the rotatable table. The distributor has a top region that is successively inserted from the back surface side of the rotatable table into the two hollow cylindrical center shafts, and a basal portion secured to a frame.

## Claims

### Claim 1

A rotary table assembly comprising:
a rotatable table having a through hole extending along an axis;
a frame rotatably supporting the rotatable table from a back surface side of the rotatable table;
a rotary joint including a hollow cylindrical center shaft having a plurality of rotatable-table-side fluid passages, and a distributor having a plurality of frame-side fluid passages and being inserted into a center bore of the center shaft, the rotary joint being disposed in the through hole to receive and supply fluid between the frame-side fluid passages and the rotatable-table-side fluid passages; and
a sealing member interposed between an outer peripheral surface of the center shaft and a peripheral surface of the through hole, wherein
the center shaft includes a rotatable-table-side center shaft that is inserted into the through hole from a front surface side of the rotatable table and has the outer peripheral surface making contact with the sealing member, and a frame-side center shaft that is inserted into the through hole from the back surface side of the rotatable table, wherein the frame-side center shaft and the rotatable-table-side center shaft are secured to the rotatable table and are hollow and cylindrical,
the distributor includes a basal portion at a bottom end thereof adjacent to the frame and a top region axially extending from the basal portion, the top region is inserted from the back surface side of the rotatable table into a center bore of the frame-side center shaft and a center bore of the rotatable-table-side center shaft in succession, and the basal portion is secured to the frame,
communication ports of first ones of the frame-side fluid passages formed on an outer peripheral surface of the top region are in communication with communication ports of first ones of the rotatable-table-side fluid passages formed on an inner peripheral surface of the rotatable-table-side center shaft, and communication ports of second ones of the frame-side fluid passages formed on the outer peripheral surface of the top region are in communication with communication ports of second ones of the rotatable-table-side fluid passages formed on an inner peripheral surface of the frame-side center shaft.

### Claim 2 (depends on 1)

The rotary table assembly according to claim 1, wherein the rotary joint further includes a coupling member that fixedly couples the frame-side center shaft and the rotatable-table-side center shaft.

### Claim 3 (depends on 2)

The rotary table assembly according to claim 2,
wherein the first frame-side fluid passages extend axially in both the basal portion and the top region of the distributor, the first rotatable-table-side fluid passages extend axially only in the rotatable-table-side center shaft and not in the frame-side center shaft, the second frame-side fluid passages extend axially only in the basal portion and not in the top region of the distributor, and the second rotatable-table-side fluid passages extend axially in both the rotatable-table-side center shaft and the frame-side center shaft, and
wherein one of air or liquid flows through the first frame-side fluid passages and the first rotatable-table-side fluid passages, while the other of air or liquid flows through the second frame-side fluid passages and the second rotatable-table-side fluid passages.