| 摘要 |
An auxiliary air bearing system (50) for reducing friction in mechanical bearings (41, 42) to improve repeatability of measurements on a coordinate measuring machine (10). The air bearing system (50) and mechanical bearings (41, 42, 43) support a moveable carriage (30) on a base (20). The air bearing system (50) comprises an air pad assembly (70) mounted to the carriage (30), an air system (80) supplying air under pressure and a rail system (60) mounted to the base (20) with the air pad (70) including a compressed spring (76) captivated therein. Air under pressure is directed between the air pad assembly (70) and the rail system (60), causing the air pad assembly (70) to lift from the rail system (60) and the base (20). The air bearing system (50) and the spring (76) reduce the effect of any irregularities on the rail that would otherwise cause measurement errors. The air bearing system (50) is preferably mounted obliquely to two of the mechanical bearings (41, 42) so that a single air bearing assembly reduces the friction in the mechanical bearings supporting the carriage in two directions.
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