A Hydrostatic Electric Spindle with Intra-cavity Feedback Throttling

Abstract

The invention discloses a feedback throttling hydrostatic electric spindle in a cavity, which includes a machine body, a hydrostatic bearing and a rotating shaft. The rotating shaft is fitted in the body through the hydrostatic bearing. The inner wall of the pressure bearing is provided with throttles, and the throttles are provided with an even number, and every two throttles are arranged opposite to each other. The throttles include throttle bosses, oil collection chambers and Working oil chamber, the throttling boss communicates with the external oil inlet branch of the hydrostatic bearing, the oil collecting chamber surrounds the throttling boss, and the working oil chamber surrounds the oil collecting The oil chamber, the working oil chamber and the oil collection chamber are separated by the first oil sealing flange, and the oil collection chamber of one of the two oppositely arranged restrictors is separated from the oil collection chamber of the other. The working oil cavity of the operator is connected. The feedback throttling hydrostatic electric spindle in the cavity can ensure effective throttling, stable performance and easier processing, thereby improving the rigidity of the rotating shaft.

Description

technical field [0001] The invention relates to the technical field of electric spindles, in particular to a feedback throttling hydrostatic electric spindle in a cavity. Background technique [0002] Machine tool spindle is the core functional component of modern machine tools, its function is to drive the tool (grinding wheel) or workpiece to rotate, and realize high-speed precision machining. The hydrodynamic and static piezoelectric spindle is a new type of machine tool spindle functional component that is supported by a hydrostatic bearing and integrates the functions of the machine tool spindle and the motor from the structure. [0003] With the continuous improvement of modern industry's requirements for machining accuracy and machining efficiency of machine tools, machine tools have higher and higher requirements for spindle performance. Compared with the traditional belt drive spindle, the hydrostatic electric spindle saves the complicated intermediate transmission...

AI Technical Summary

Problems solved by technology

[0008] Thin-film feedback throttling: Its advantage is that the shaft can obtain greater oil film stiffness under low oil inlet pressure and large clearance. The disadvantage is that it has high requirements on the characteristics of the film material and manufacturing process, and the consistency of the film restrictor is difficult. Guaranteed, as soon as the manufactured restrictor deviates from the actual range, the stiffness characteristics of the bearing will be greatly reduced

[0009] Spool valve feedback throttling: Its advantage is that it can adapt to the working conditions with large load changes. The disadvantage is similar to that of film feedback. At the same time, there is a throttle that is too large in size and needs to be connected to the outside through the oil circuit, and the throttle response speed is easily affected.

[0010] Compared with film feedback throttling and spool valve feedback throttling, internal feedback throttling has a simpler structure, faster response and better rigidity; however, internal feedback throttling in current engineering applications has its throttling link located outside the oil chamber , such an external throttling form increases the span of the main shaft, making it difficult to optimize the rigidity of the shafting system; it increases the friction area of ​​the liquid and generates a large amount of heat, and it is easy to cause the shaft to be locked due to the temperature rise; due to the large fuel consumption , the corresponding pump power consumption is also relatively large, and at the same time, a large amount of oil is likely to cause leakage and difficult sealing problems

[0011] In order to overcome the above-mentioned defects of feedback throttling inside and outside the cavity, someone proposed a three-row slot type oil cavity internal feedback throttling hydrostatic bearing structure, but this structure has the following obvious defects: hidden danger of throttling failure: due to the same oil cavity There is no secondary throttling link between the oil chamber of the oil tank and the working oil chamber, and the oil hydraulic pressure difference between the two oil chambers is very large, which easily leads to direct oil leakage, and the fluid state such as internal flow of pressure oil and turbulent flow is complicated, which brings Hydraulic oil leakage or even throttling failure hidden dangers

Unstable performance: The design requirements of the throttling parameters of this structure vary with the layout of the oil circuit, and there are many arrangements and combinations of the oil circuit layout, and the actual performance differences brought about by different oil circuit layouts are very large; the processing is difficult: According to the design theory of hydrostatic bearings, the hydrostatic bearing adopting the throttling method of three rows of grooves objectively requires a narrow throttling edge width to achieve reasonable rigidity, but narrow throttling edges are difficult to guarantee in actual processing, even if inverted Inconsistent angle sizes will also lead to great differences in throttling effects, so it is difficult to realize in actual processing, so it is difficult to apply and popularize in actual engineering

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