JPH08320024A - Bearing cooling device for main shaft - Google Patents

Abstract

PURPOSE: To provide a bearing cooling device which performs cooling of a bearing simply and surely by means of an outer ring cooling means which directly cools the outer ring of the bearing. CONSTITUTION: A main shaft 1 supported by a plurality of bearings 3, 4 is rotatably arranged inside a housing 2. A spiral groove of a jacket is formed in a wall surface of the housing 2, and cooling liquid is charged thereinto for cooling the housing. Spiral grooves CG, 2C, 2E are formed on an inner peripheral side of the housing 2 for supporting the bearings 3, 4 of the main shaft 1. The spiral grooves 2C, 2E are in contact with outer rings of the bearings 3, 4, and thereby a bearing cooling device of the main shaft is provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spindle for a machine tool and a cooling device for this bearing, and more particularly to a cooling device for a bearing portion which can be implemented by simple means.

[0002]

2. Description of the Related Art Conventionally, a cooling device for a spindle and bearings of a machine tool is constructed as shown in FIG. 4, for example. The main shaft 1 is rotatably provided in a housing 4 supported by a plurality of bearings 2 and 3. To cool the main shaft 1 and the bearings 2 and 3, a jacket 5 having a spiral groove 5A is attached to the outer periphery of the housing 4 in an airtight manner, and a cooling liquid C is injected into the spiral groove 5A of the jacket 5 from a pipe 6 to 4 and the bearings 2 and 3 are cooled.

[0003]

However, in the cooling device for the main shaft and bearings, the cooling effect of the main shaft housing 4 and the bearings 2 and 3 is not sufficiently exerted. That is, all of the cooling liquid C is used only for directly cooling the housing 4, and is the cooling centering around the outer peripheral skin portion of the housing 4, so that the cooling of the important bearings 2 and 3 located far from this is performed. The effect is hardly exerted.

In view of the problems of the conventional cooling devices for the main shaft and bearings, the present invention provides a bearing cooling device which can be simply and surely implemented by an outer ring cooling means for directly cooling the outer ring of the bearing. The purpose is to

[0005]

In order to achieve the above object, the present invention provides a main shaft supported by a plurality of bearings rotatably in a housing according to claim 1, and a spiral of a jacket in a wall surface of the housing. In a case where a groove is provided to inject a cooling liquid into the groove to cool the housing, a spiral groove is provided on the inner peripheral side of the housing that supports the bearing of the main shaft, and the spiral groove is in contact with the outer ring of the bearing. This is a bearing cooling device for the main shaft.

In order to achieve the above object, the present invention provides claim 2.
In the one in which the main shaft supported by a plurality of bearings is rotatably provided in the housing, and the spiral groove of the jacket is provided in the wall surface of the housing to inject the cooling liquid into the spiral groove to cool the housing and the bearing. Provide a spiral groove on the inner peripheral side of the housing that supports the bearing,
The bearing groove cooling device for the main shaft is characterized in that the spiral groove is in contact with the outer ring of the bearing, the bearing spacers, and the inner peripheral space of the housing.

In order to achieve the above object, the present invention provides claim 2.
3. The spindle bearing cooling device according to claim 1, wherein the portion where the outer ring of the bearing is in contact with the spiral groove of the housing faces a position where the external force applied to the outer ring of the bearing is low. It is a device.

[0008]

According to the first and second aspects of the present invention, the spiral groove is provided on the inner peripheral side of the housing that supports the bearing of the main shaft, and the spiral groove is in contact with the outer ring of the bearing, each bearing spacer and the inner peripheral space of the housing. When the cooling liquid is supplied to the spiral groove of the housing, the outer ring of the bearing, the bearing spacers and the inner peripheral portion of the housing are directly and efficiently cooled. In addition, since the jacket is not separately provided on the outer periphery of the housing, the housing itself becomes thick and the rigidity is increased.

Further, according to claim 3 of the present invention, since the portion where the outer ring of the bearing is in contact with the spiral groove of the housing faces the position where the external force applied to the outer ring of the bearing is low, the housing has a holding ability for the bearing. Stable bearing holding is achieved without lowering.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The embodiments shown in the drawings will be described below. FIG. 1 is a vertical cross-sectional view showing an entire bearing cooling device for a spindle in a machine tool according to the present invention, and FIGS. 2 and 3 are cross-sectional views of a main part according to the present invention. FIG. 4 is a sectional view showing a conventional bearing cooling device.

First, in FIG. 1, the main shaft 1 is fitted and supported on the inner hole wall 2X of the housing 2 by the two bearings (bearings) 3 on the front end side, and the rear end side is also not shown. It is supported by bearings. Further, although not shown, the main shaft 1 is fitted with a rotor of a built-in motor in the middle abdomen thereof, and a multi-layer disc spring and a drawing bar 7 are installed in the inner peripheral hole 1A opened at the axial center position.
The collet 6 strongly pulls in the pull stat 5 of the tool H1 inserted into the tapered hole 1B at the tip of the spindle and fits it. An unclamping device is provided at the rear end of the drawing bar 2, and when the drawing bar 2 is advanced to the drawing bar side, the drawing bar is strongly pushed out to perform the unclamping operation.

A cooling liquid O for cooling the outer rings of the bearings 3 and 4 and cooling the inner circumference of the housing 2 is supplied to the housing 2 through a through hole 11 opened at the tail end. The through hole 11 has a forward path and a return path 11 in the longitudinal direction of the main shaft 1.
′ Is extended, and a spacer 9 is interposed between the two bearings 3 and 4 that support the tip end side of the main shaft 1. The spiral groove CG is formed in the inner peripheral hole 2A of the housing facing the spacer 9 on the outer peripheral side.
And the spiral groove CG faces the spacer 9. And
The spiral groove CG is connected by connecting paths 11A and 11B that connect the outward and return paths of the through holes 11 and 11 '. Further, annular grooves 2C, 2E or spiral grooves are provided in the inner peripheral hole 2A of the housing that fits with the outer rings 3A, 4A of the bearings 3, 4, and these are connected to the annular grooves 2C, 2E by the communication holes 2B, 2D. Has been. In addition, the through hole 11 'which becomes the return path
Are connected to the annular grooves 2C and 2E by communication holes 2F and 2G. The details are as shown in FIGS. 1 and 2 and 3. In particular, the annular grooves 2C and 2E of the housing that fit with the outer rings 3A and 4A of the bearings 3 and 4 are arranged facing each other at a position where the external force F applied to the outer rings of the bearing is low.

The bearing cooling device for the main shaft according to the present invention is constructed as described above and operates as follows. First, the cooling liquid O for cooling the outer races of the bearings 3 and 4 and the inner circumference of the housing 2 is supplied from the through hole 11 opened at the tail end of the housing 2. Part of the cooling liquid O is
In order to cool the outer rings 3A, 4A of the bearings 3, 4,
From the connecting holes 2B and 2D connected to the through hole 11 to the annular groove 2
C, 2E, and the annular grooves 2C, 2E face the outer rings of the bearings 3, 4. As a result, the cooling liquid C cools the outer rings 3A, 4A of the bearings 3, 4. The cooled cooling liquid C is discharged from the communication holes 2F and 2G to the return path 11 'and discharged to the outside.

For cooling the inner circumference of the housing 2, the cooling liquid O is supplied from the through hole 11 of the housing 2. Most of the cooling liquid O is sent to the spiral groove CG from the communication path 11A in order to cool the bearing spacer 9 and the inner circumferential space of the housing. As a result, the cooling fluid O cools the spacer 9 of the bearing and the inner peripheral space of the housing while swirling in the spiral groove CG, and finally from the communication path 11B to the return path 11 '.
Sent to.

The outer rings 3A, 4 of the bearings 3, 4 are
When cooling A, as shown in FIGS. 2 and 3, the portion where the outer ring of the bearing is in contact with the spiral groove of the housing faces the position where the external force F applied to the outer ring of the bearing is low, so that the housing does not contact the bearing. Stable bearing retention is guaranteed without compromising retention.
Further, since the jacket is not separately provided on the outer periphery of the housing 2, the housing itself becomes thick and the rigidity can be enhanced.

The present invention is not limited to the above-mentioned embodiment, and the design of the essential structure can be changed. For example, the number of the bearings 2 is not limited, and the bearings may be provided with cooling means only on the outer ring of the bearings.

[0017]

According to the first and second aspects of the present invention, the spiral groove is provided on the inner peripheral side of the housing that supports the bearing of the main shaft, and the spiral groove is in contact with the outer ring of the bearing, each bearing spacer, and the inner peripheral space of the housing. When the cooling liquid is supplied to the spiral groove of the housing, there is an effect that the outer ring of the bearing, the bearing spacers and the inner peripheral portion of the housing are directly and efficiently cooled. Therefore, the ideal cooling characteristic can be implemented by a simple and simple means, and the heat generation of the main shaft and the bearing can be reasonably suppressed.

Further, according to claim 3 of the present invention, since the portion where the outer ring of the bearing is in contact with the spiral groove of the housing faces the position where the external force applied to the outer ring of the bearing is low, the housing has a holding ability for the bearing. Stable bearing holding is achieved without lowering, which is effective.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view showing an entire bearing cooling device for a spindle of a machine tool according to the present invention.

FIG. 2 is a sectional view of a main part according to the present invention.

FIG. 3 is a sectional view of a main part according to the present invention.

FIG. 4 is a cross-sectional view showing a conventional bearing cooling device.

[Explanation of symbols]

 1 Spindle 2 Housing 2X Inner hole wall 2B, 2D, 2F, 2G Connecting hole 2C, 2E Annular groove CG Spiral groove O Coolant 3,4 Bearing 3A, 4A Outer ring 7 Drawing bar 9 Spacer 11 Passage (outward) 11 'Passage (Return route) 11A, 11B connecting route

Claims (3)

[Claims] 1. A main shaft in which a main shaft supported by a plurality of bearings is rotatably provided in a housing, and a spiral groove of a jacket is provided in a wall surface of the housing to inject a cooling liquid into the spiral groove to cool the housing. Bearing cooling device for a main shaft, wherein a spiral groove is provided on an inner peripheral side of a housing that supports the bearing, and the spiral groove is in contact with an outer ring of the bearing. 2. A main shaft in which a main shaft supported by a plurality of bearings is rotatably provided in a housing, and a spiral groove of a jacket is provided in a wall surface of the housing to inject a cooling liquid into the spiral groove to cool the housing. A bearing cooling device for a main shaft, characterized in that a spiral groove is provided on an inner peripheral side of a housing that supports the bearing, and the spiral groove is in contact with an outer ring of the bearing, each bearing spacer, and an inner peripheral space portion of the housing. 3. The bearing cooling device for a main shaft according to claim 1, wherein a portion where the outer ring of the bearing is in contact with the spiral groove of the housing faces a position where the external force applied to the outer ring of the bearing is low. Spindle bearing cooling system.