Active airbearing device

Patent metadata

Field	Value
Publication number	US-9920790-B2
Application number	US-201415126537-A
Country	US
Kind code	B2
Filing date	Apr 2, 2014
Priority date	Mar 18, 2014
Publication date	Mar 20, 2018
Grant date	Mar 20, 2018

Abstract

The present invention discloses an active airbearing device, including a airbearing body, a gas film active adjusting unit, a support body detection unit and a drive control unit, wherein the support body detection device measures a state of airbearing, the drive control system generates a control signal according to a detection signal, drives and controls the gas film active adjusting device to generate an active action, and dynamically adjusts the form of gas films on a airbearing surface, so as to dynamically adjust pressure distribution of gaps between the gas films of the airbearing device, thereby improving dynamic stiffness characteristics of the airbearing. Through the present invention, the dynamic stiffness characteristics of the airbearing can be improved significantly, and the purpose of stabilizing the airbearing is achieved; in addition, the active airbearing device according to the present invention also has the characteristics of a compact structure, convenient operation and control, and high precision, and thus is especially suitable for occasions such as ultra-precision machining or high speed spindle which has high requirements for dynamic stiffness of support.

First claim

The invention claimed is:

1. An active airbearing device for supporting a precise moving component, the device comprising:
an airbearing body;
a gas film active adjusting unit;
a support body detection unit; and
a drive control unit, wherein:
the airbearing body is a bearing structure internally provided with a gas channel, and is mounted with a throttler in a gas outlet of the gas channel facing a gas suspension guide rail;
the gas film active adjusting unit includes a plurality of piezoelectric actuators, which are fixedly mounted to the side of the gas outlet of the airbearing body and are machined with the side of the gas outlet to form a continuously flat surface to be jointly used as a working face of the airbearing device, when compressed gas flows into a gap between the working face and the gas suspension guide rail through the throttler, a gas suspension gas film is formed, and the airbearing body and a moving component fixed therewith are suspended above the gas suspension guide rail;
the support body detection unit comprises a position sensor having a measurement precision of more than 0.2 μm, and one of a velocity sensor and an acceleration sensor having a frequency measurement range of more than 50 Hz, the position sensor and the one of the velocity sensor and the acceleration sensor are fixedly arranged on the airbearing body or the precise moving component, and the position sensor and the one of the velocity sensor and the acceleration sensor are respectively used to detect in real time a position variation value and one of a velocity variation value and an acceleration variation value of the airbearing body relative to a supporting direction of the gas film, thereby obtaining a thickness variation value of the gas film of the airbearing device; and
the drive control unit is respectively connected to the gas film active adjusting unit and the detection device by wire, the drive control unit is configured to filter, amplify and process a signal sensed by the detection device so as to generate a corresponding drive signal to drive the gas film active adjusting unit to execute an expanding or contracting action, thereby changing the overall shape of the working face of the airbearing device, which acts as the gas suspension gas film, and changing pressure distribution on the gas suspension gas film in the meantime so as to achieve a process of actively regulating dynamic stiffness of the airbearing device.

2. The active airbearing device according to claim 1 , wherein, when the airbearing body is a cylindrical bearing structure, the gas film active adjusting unit includes a plurality of piezoelectric actuators jointly and is designed as a coaxially distributed ring body; and when the airbearing body is a rectangular bearing structure, the gas film active adjusting unit is composed of the plurality of piezoelectric actuators jointly and is designed as an array-distributed rectangular body.

3. The active airbearing device according to claim 1 , wherein the plurality of piezoelectric actuators complete fixing and adhesion between each other and between the piezoelectric actuators and the airbearing body through an adhesive material.

Assignees

• Univ Huazhong Science Tech

Inventors

• Jiang Wei
• Chen Xuedong
• Luo Xin
• Zeng Lizhan

Classifications

• F16C2322/39

  General buildup of machine tools, e.g. spindles, slides, actuators · CPC title

• F16C32/0607 Primary

  the gas being retained in a gap, e.g. squeeze film bearings · CPC title

• F16C32/067

  of bearings adjustable for aligning, positioning, wear or play · CPC title

• F16C32/0614 Primary

  the gas being supplied under pressure, e.g. aerostatic bearings · CPC title

• F16C29/00

  Bearings for parts moving only linearly (F16C32/06 takes precedence; incorporated in flexible shafts F16C1/28 {; parts of bearings in general and special methods for making bearings or parts thereof in general F16C33/00}) · CPC title