Built-in variable throttler

Abstract

A built-in variable throttler comprises a throttler seat, a throttling post and a spring. A stair-step centre hole is arranged on the throttler seat and composed of a big diameter hole, a middle diameter hole and a small diameter hole, the big diameter hole is communicated with the small diameter hole through the middle diameter hole, the throttling post is formed by connecting a big diameter post, a middle diameter post and a small diameter post, the throttling post is installed in the throttler seat, the big diameter post is tightly matched with the big diameter hole, an oil storage chamber is defined by the top end of the big diameter post and the inner wall of the big diameter hole, an oil inlet chamber is formed between the middle diameter post and the big diameter hole, an oil inlet channel for communicating the oil storage chamber and the oil inlet chamber is arranged on the throttling post, a throttling gap communicated with the oil inlet channel is formed between the middle diameter post and the middle diameter hole, an oil collecting chamber is formed between the small diameter post and the middle diameter hole, the small diameter post is tightly matched with the small diameter hole, an output channel communicated with the oil collecting chamber is arranged on the small diameter post, and a spring abuts against and is arranged between the bottom end of the middle diameter post and the bottom end of the middle diameter hole. The built-in variable throttler is simple and compact in structure, and rapid in changing dynamic response of external loads.

Description

technical field [0001] The invention relates to a throttling device for the main shaft of a machine tool with hydrostatic pressure and dynamic and static pressure bearings in precision and ultra-precision machine tools, in particular to a built-in variable throttle device. Background technique [0002] Precision and ultra-precision machining are indispensable means for the processing of aerospace optical components, key parts of national defense equipment and key parts of high-end civilian equipment. Precision and ultra-precision machining mainly depend on precision and ultra-precision machine tools. Due to the unique "error equalization effect", dynamic pressure effect and damping and vibration reduction effect of hydrostatic pressure and dynamic and static pressure bearing machine tool spindles, their rotation accuracy is much higher than that of rolling bearing spindles, and their carrying capacity is much higher than that of gas static pressure spindles. Therefore, it h...

AI Technical Summary

Problems solved by technology

The disadvantages of film feedback throttling and spool valve feedback throttling are: (1) The restrictor has a large structural size and can only be placed outside the bearing body, so the feedback oil circuit is longer and the dynamic response to external load changes is relatively slow. Slow, which affects the improvement of dynamic stiffness; (2) The large size of the throttle increases the overall space occupied by the machine tool spindle; (3) The throttle is divided into two ways to supply oil to the two opposite oil chambers, The stiffness of the opposite oil chamber is affected by the parameters of the same restrictor at the same time. If the parameters are not selected properly, it is easy to cause the stiffness of the spindle system to be unstable and cause the spindle to fail to work normally.

The disadvantages of internal surface feedback throttling are: (1) It needs to occupy the area of ​​the inner surface of the bearing oil chamber, resulting in a larger axial dimension of the bearing. For bearings with small inner hole sizes, inner surface throttling is difficult to process; (2) ) Due to the increased area of ​​the inner surface, when the spindle rotates, the shear heat between the inner surface and the oil film increases, and the temperature rise of the bearing rises, which is not conducive to improving the high-speed performance of the spindle

[0007] Due to the above-mentioned defects, the throttling method adopted by the existing hydrostatic pressure and dynamic and static pressure bearing machine tool spindles has not been fully applied on machine tools at present, and has not been able to realize mass production as a unit functional component

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