Main shaft device

Abstract

A cooling passage through which a cooling medium can flow is formed between the inner peripheral surface of a rear housing, and the outer peripheral surface of a bearing sleeve having a free-side bearing inserted therein. The cooling passage is formed in the outer peripheral surface of the bearing sleeve, and comprises one or a plurality of helical grooves formed in the outer peripheral surface of the sleeve from one-end side of the sleeve in the axial direction to another-end side of the sleeve in the axial direction. The housing is provided with: a supply port which communicates with one end of the helical grooves, and through which the cooling medium is supplied; and a discharge port which communicates with another end of the helical grooves, and through which the cooling medium that has flowed through the cooling passage is discharged.

Description

technical field [0001] The present invention relates to a spindle device, and more specifically, to a spindle device of a high-speed rotating machine such as a machine tool spindle, a high-speed motor, a centrifugal separator, or a turbo refrigerator. Background technique [0002] The increase in the speed of the spindle of the machine tool has progressed remarkably, and oil-air lubrication and oil-mist lubrication have been used as lubrication methods for increasing the spindle speed. In addition, as another lubricating method, from the viewpoint of environmental protection, grease lubrication, which does not discharge lubricating oil to the outside, has been newly recognized again, and the rolling bearings used are made of lightweight ceramics with excellent burn resistance under high-speed rotation. Rolling elements (such as silicon nitride, etc.). [0003] In addition, as a driving method for a high-speed rotating spindle, there are more so-called built-in motor spindle...

AI Technical Summary

Problems solved by technology

In addition, since the rear side bearing is the free side; and the degree of influence of thermal deformation on the machining accuracy of the rear of the spindle is smaller than that of the front side bearing (for example, even if the rotating shaft is relatively expanded in the axial direction with respect to the non-rotating element, The rear side of the spindle also slides backward, which is difficult to occur in the displacement of the front side of the spindle on which the tool is installed), etc. In most cases, no complicated cooling structure is added to the rear side bearing.

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