MACHINE TOOL AND MACHINING METHOD

• US 20140202294A1
• Filed: 08/29/2012
• Published: 07/24/2014
• Est. Priority Date: 08/31/2011
• Status: Active Grant

• Current Assignee: Citizen Watch Co Limited (Citizen Electronics Company Limited)
• Original Assignee: Citizen Holdings Co., Ltd., Citizen Machinery Miyano Co., Ltd.
• Inventors: Takahashi, Hikaru
• Granted Patent: US 9,463,512 B2
• Time in Patent Office: Days
• US Class Current: 82/1.11
• CPC Class Codes: B23B 1/00 Methods for turning or working essentially requiring the use of turning-machines; Use of auxiliary equipment in connection with such methods
• CPC Class Codes: B23B 13/126 Supports
• CPC Class Codes: B23B 2265/12 Eccentric
• CPC Class Codes: B23B 25/00 Accessories or auxiliary equipment for turning-machines for machine tools in general B23Q; cooling or lubricating B23Q11/12
• CPC Class Codes: B23B 5/18 for turning crankshafts, eccentrics, or cams, e.g. crankpin lathes
• CPC Class Codes: B23B 7/06 with sliding headstock
• CPC Class Codes: B23Q 1/763 Rotating steadies or rests
• CPC Class Codes: G05B 2219/49313 Machining about eccentric center different from rotational center of workpiece
• CPC Class Codes: Y10T 82/10 Process of turning
• CPC Class Codes: Y10T 82/13 Pattern section
• CPC Class Codes: Y10T 82/19 Lathe for crank or crank pin
• CPC Class Codes: Y10T 82/2597 Center rest

Abstract

A machine tool includes a main spindle (10) which holds a workpiece (200, object to be machined) and is rotatable about the shaft center (C1), a main spindle motor (20, main spindle driver) which rotates the main spindle (10), a rotary guide bush (30, eccentric guide hush) which supports the workpiece (200) projecting from a leading end of the main spindle (10) to be rotatable in a state of being eccentric relative to the shaft center (C1) by a length E, a guide bush servomotor (40, guide bush driver) which rotates the rotary guide bush (30) about the shaft center (C1) in synchronization with the main spindle (10), and a controller (50) which controls the rotation and driving of the guide bush servomotor (40), so as to selectively switch between the rotation state and the stop state of the rotation.

Claims

1. A machine tool comprising an eccentric guide bush which supports an object to be machined projecting from a leading end of a main spindle in a state of being eccentric relative to a shaft center of the main spindle.

2. The machine tool according to claim 1, wherein the eccentric guide bush is switched between a rotation state rotating about the shaft center of the main spindle and a stop state.

3. The machine tool according to claim 2, further comprising:

a main spindle driver which rotates the main spindle about the shaft center;

a guide bush driver which rotates the eccentric guide bush about the shaft center; and

a controller which controls the guide bush driver, so as to switch the eccentric guide bush between the rotation state rotating about the shaft center in synchronization with the main spindle and the stop state.

4. The machine tool according to claim 1, wherein

the rotation of the eccentric guide bush and the rotation of the main spindle are adjusted, so as to change a phase of the object to be machined in a portion of the eccentric guide bush, which eccentrically supports the object to be machined.

5. The machine tool according to claim 4, further comprising:

a main spindle driver which rotates the main spindle about the shaft center;

a guide bush driver which rotates the eccentric guide bush about the shaft center; and

a phase controller which controls at least one of the main spindle driver and the guide bush driver, so as to change the phase of the object to be machined in a portion of the eccentric guide bush, which eccentrically supports the object to be machined.

6. The machine tool according to claim 1, wherein

a corner portion adjacent to an inner circumferential surface supporting the object to be machined in an end face facing the main spindle in an end face of the eccentric guide bush is chamfered.

7. A machining method comprising:

rotating a main spindle about a shaft center; and

machining an object to be machined by using an eccentric guide bush which supports the object to be machined projecting from a leading end of the main spindle in a state of being eccentric relative to a shaft center of the main spindle.

8. The machining method according to claim 7, further comprising:

switching the eccentric guide bush between a rotation state rotating about the shaft center of the main spindle and a stop state.

9. The machining method according to claim 7, further comprising:

adjusting the rotation of the electric guide bush and the rotation of the main spindle so as to change a phase of the object to be measured in a portion of the eccentric guide bush, which eccentrically supports the object to be measured.