Spindle unit and machining device

Abstract

The invention provides a main shaft unit and a machining device. The main shaft unit is provided with an air bearing which enables a main shaft to continuously rotate even under the condition of thermal deformation and is excellent in load resistance. The main shaft unit includes a main shaft to which a machining tool is mounted at a tip end, and a main shaft housing having a thrust bearing and a radial bearing that rotatably support the main shaft by air in a non-contact manner, the thrust bearing having: an air supply unit that supplies air to the main shaft; the air supply part is used for supplying air to a gap between the outer side face of the main shaft and the inner side face of the main shaft shell in the direction perpendicular to the axial direction of the main shaft; and an adjusting part capable of adjusting the distance of the gap in the direction perpendicular to the outer side surface of the main shaft.

Description

technical field [0001] The invention relates to a spindle unit and a machining device. Background technique [0002] A grinding apparatus for grinding a wafer held by a chuck table includes a spindle unit including a spindle. In this grinding device, a grinding wheel on which a ring-shaped grinding wheel is arranged is attached to the front end of a main shaft. The wafer is ground by a grinding wheel that is rotated by rotating a spindle. [0003] As disclosed in Patent Document 1, the spindle unit includes: a spindle housing that forms a gap to surround the outer peripheral surface of the spindle; and an air supply unit that supplies air to the gap. The gap is filled with air and pressurized, thereby forming an air bearing. [0004] In addition, regarding the main shaft, as disclosed in Patent Document 2, by measuring the pressure of the air in the gap, it is possible to measure the load applied to the grinding wheel. [0005] Patent Document 1: Japanese Patent Applicat...

AI Technical Summary

Problems solved by technology

[0008] However, since the gap is narrow, thermal deformation of the casing or the main shaft may occur due to the supply of air for forming the air bearing, the passage of cooling water, etc., at the initial stage of device startup.

In this case, there is a contact portion where the main shaft and the case come into contact, and when the main shaft is rotated, the contact portion may rub against and form unevenness, and the main shaft may not be able to rotate.

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