JPH1148088A - Spindle head of machine tool - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a spindle head which can secure a high processing accuracy by effectively preventing generation of thermal strain in a housing constituting the spindle head of a machine tool. SOLUTION: The spindle head of a machine tool is composed of a spindle 1, bearing 2 to support the spindle 1, motor 3 to drive the spindle 1, and a housing 4 to accommodate them. The housing 4 is furnished internally with an air passage 5 to serve for the cooling operation, and a fan 6 to send air into the air passage 5 forcedly is installed at the inlet to the air passage 5.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spindle head of a machine tool, and more particularly to a structure for enhancing cooling of the spindle head.

[0002]

2. Description of the Related Art Conventionally, in a spindle head of a machine tool, cooling is used for lubrication of the bearing in order to suppress heat generation from a bearing portion due to high speed rotation and a stator of a built-in motor housed in the spindle head. Oil air lubrication or oil mist lubrication is widely used. Further, in order to effectively suppress heat generation of the stator of the built-in motor, a cooling jacket is provided inside the main shaft. However, no special cooling has been performed on the housing that houses the main shaft, the bearing, and the built-in motor, and only natural cooling has been performed by the outside air.

[0003] In the conventional cooling method as described above, the cooling of the housing is insufficient, and the rise in the temperature of the housing cannot be sufficiently suppressed. For this reason, deformation of the housing occurs due to thermal strain, and this is one of the factors that cause a decrease in accuracy of the machine tool.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned structural problems of a spindle head of a conventional machine tool, and an object of the present invention is to provide a housing constituting a spindle head. An object of the present invention is to provide a spindle head capable of ensuring high machining accuracy by effectively preventing the occurrence of thermal strain.

[0005]

A spindle head of a machine tool according to the present invention is a spindle head of a machine tool including a spindle, a bearing for supporting the spindle, a motor for driving the spindle, and a housing for accommodating the spindle. The housing has a cooling air passage formed therein, and a fan for forcing air to flow into the air passage at an inlet side or an outlet side of the air passage.

According to the spindle head of the machine tool of the present invention, when machining is performed using the spindle head, it is possible to forcibly feed air into the air passage formed inside the housing using the fan. it can. Thereby, a rise in the temperature of the housing is suppressed, and deformation of the housing due to thermal strain can be prevented. As a result, machining accuracy by the spindle head can be improved.

Usually, the shape of the main shaft is cylindrical, whereas the shape of the housing for accommodating the main shaft and the like is often a rectangular parallelepiped due to the relationship with other parts. Therefore, if the air passages are formed in the thick portions at the four corners of the housing, the air passages can be provided without increasing the outer dimensions of the housing.

[0008]

1 and 2 show an example of a spindle head according to the present invention. 1 is an axial sectional view of the spindle head, and FIG. 2 is a view in the Z direction of FIG. In the figure, 1 is a main shaft, 2 is a bearing, 3 is a built-in motor, 4 is a housing, 5 is a cooling air passage, and 6 is a fan.

The spindle head of the machining center includes a spindle 1, a bearing 2, a built-in motor 3, and a housing 4 for accommodating these components. The housing 4 has a substantially square cross section, and a cylindrical cavity 9 is formed at the center thereof. The main shaft 1 passes through the center of the hollow portion 9 of the housing 4, and the rear end (the left side in this example) of the main shaft 1 is supported by the housing 4 via the bearing 2. The intermediate portion of the main shaft 1 is incorporated in the center of the built-in motor 3, and the outer periphery of the built-in motor 3 is fixed inside the cavity 9 of the housing 4. Tip of spindle 1 (right side in this example)
, A tool is mounted.

As shown in FIG. 2, cooling air passages 5 are formed at four corners of the cross section perpendicular to the axial direction of the housing 4, and these air passages 5 are formed as shown in FIG. , Penetrate the housing 4 in the axial direction. Fans 6 are provided at one end of each air passage 5 (in this example, the end on the tip end side of the main shaft). By sending outside air into each air passage 5 using these fans 6, forced air cooling of the housing 4 is performed. The air sent into the air passages 5 is discharged from the other end of each air passage 5 (in this example, the end on the rear end side of the main shaft).

In this example, oil mist lubrication is used for lubrication of the bearing 2 and an oil mist exhaust hole 11 is formed near the outer periphery of the bearing of the bearing 2. One of the four air passages 5 has the other end connected to an oil mist collection device 12, and the oil mist exhaust hole 11
The oil mist recovery device 12 is connected via the air passage 5. The oil mist injected into the bearing 2 is sent to the oil mist recovery device 12 through the oil mist exhaust hole 11 and the air passage 5 in this order.

As described above, the air passage 5 is
The temperature rise of the housing 4 is suppressed by forcibly sending outside air to the housing 4, whereby deformation of the housing 4 due to thermal strain is prevented, and machining accuracy by the spindle head can be improved.

[0013]

According to the spindle head of the machine tool of the present invention, by forcibly cooling the housing, deformation of the housing due to thermal distortion is prevented, and machining accuracy by the spindle head can be improved.

[Brief description of the drawings]

FIG. 1 is an axial sectional view of a spindle head of a machine tool according to the present invention.

FIG. 2 is a view in the direction of the arrow Z in FIG. 1;

[Description of Signs] 1 ... spindle, 2 ... bearing, 3 ... built-in motor, 4 ... housing, 5 ... air passage for cooling, 6 ... fan, 11 ... Mist exhaust hole, 12 ... Mist collection unit.

Claims (1)

[Claims] 1. A main shaft head of a machine tool including a main shaft, a bearing supporting the main shaft, a motor for driving the main shaft, and a housing accommodating the main shaft, wherein the housing has a cooling air passage formed therein. A spindle head of the machine tool, wherein a fan for forcing air to flow into the air passage is provided on an inlet side or an outlet side of the air passage.