# US 2018/0021904 A1 · Main spindle device for machine tool

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 2018/0021904 A1
- Document ID: US20180021904A1
- Status: Published application
- Kind: A1
- Application number: 15/629,928
- Filed: 2017-06-22
- Published: 2018-01-25
- Earliest claimed: 2016-07-19
- Assignees: Okuma Corporation
- Applicants: Okuma Corporation
- Inventors: Issei KOIKE; Naoki Kawada
- Web page: https://patentgrep.com/patent/US20180021904A1

## CPC

- B23Q 11/0039: {by changing the natural frequency of the system or by continuously changing the frequency of the force which causes the vibration}
- B23Q 1/70: Stationary or movable members for carrying working-spindles for attachment of tools or work {(B23Q1/01 takes precedence; designed to be moved by using particular mechanisms B23Q1/44)}
- B23Q 11/0032: {Arrangements for preventing or isolating vibrations in parts of the machine (B23B29/022, B23D47/005 take precedence; means for damping or suppressing vibrations, in general F16F)}
- F16C 19/527: {related to vibration and noise}
- F16C 25/06: Ball or roller bearings
- F16C 27/045: {with a fluid film, e.g. squeeze film damping}
- F16F 15/002: {characterised by the control method or circuitry (control of mechanical oscillations per se G05D19/00)}
- F16F 15/0235: {where a rotating member is in contact with fluid (rotary viscous dampers per se F16F9/12; suppression of vibrations in rotating systems containing a fluid F16F15/16)}
- F16C 2229/00: Setting preload
- F16C 2233/00: Monitoring condition, e.g. temperature, load, vibration
- F16C 2322/39: General buildup of machine tools, e.g. spindles, slides, actuators
- F16F 15/12: using elastic members or friction-damping members, e.g. between a rotating shaft and a gyratory mass mounted thereon ({F16F15/14} , F16F15/16 take precedence)
- F16F 2222/00: Special physical effects, e.g. nature of damping effects
- F16F 2232/02: Rotary
- 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
- F16C: SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
- F16F: SPRINGS; SHOCK-ABSORBERS; MEANS FOR DAMPING VIBRATION

## Abstract

A main spindle device for a machine tool includes a main spindle, a cushioning member, and an arithmetic unit. The cushioning member is disposed on a position where a vibration displacement of a rotator exists. The arithmetic unit uses data of a tool to be used to analyze a vibration mode in a free vibration of the rotator based on a support rigidity of a bearing, masses of respective parts of the rotator including the tool, an attenuation coefficient, and an equation of motion derived from rigidity and inertia by a rotation. An outer diameter of a sleeve positioned outside the bearing is changed such that a position of an antinode of the vibration or a position on which a vibration displacement exists in the vibration mode matches a position of the cushioning member inside the main spindle to change a preload on the bearing.

## Claims

### Claim 1

A main spindle device for a machine tool, comprising:
a main spindle rotatably supported inside a sleeve via a bearing;
a cushioning member disposed on a position where a vibration displacement of a rotator exists; and
an arithmetic unit configured to use data of a tool to be used to analyze a vibration mode in a free vibration of the rotator based on a support rigidity of the bearing, masses of respective parts of the rotator including the tool, an attenuation coefficient, and an equation of motion derived from a rigidity and an inertia by a rotation, wherein
an outer diameter of the sleeve positioned outside the bearing is changed such that a position of an antinode of the vibration or a position on which a vibration displacement exists in the vibration mode matches a position of the cushioning member inside the main spindle to change a preload on the bearing.

### Claim 2 (depends on 1)

The main spindle device for the machine tool according to claim 1, wherein:
a space is configured to be filled with a medium for applying a pressure, and the space is disposed between the housing and the sleeve on a proximity of installation positions of the respective bearings so as to have a dimension equal to or more than a width of the bearing, and
the pressure of the medium inside the space is adjusted to change the outer diameter of the sleeve positioned outside the bearing to control the preload on the bearing.