JPH04244620A - Device for dissolving run-out of machine mainshaft - Google Patents

Abstract

PURPOSE:To dissolve a gap which occures between the outer race of a bearing and a housing to cause the run-out of a machine mainshaft. CONSTITUTION:Sleeves 11, 12 whose one or both radial walls 15, 16 elastically deform are severally inserted between bearings 2, 4 for a machine mainshaft 1 and housings 9, 10 with gaps 13, 14 put between them. A pressurized fluid supply pipe 21 is connected to communicating holes 19, 20 communicating with the gaps 13, 14 in the sleeves 11, 12. The pressurized fluid is filled in the gaps 13, 14 to expand the walls 15, 16 for dissolving a gap between the outer races 7, 8 of the bearings and the housings 9, 10. Thus the gap between the mainshaft bearing and the housing dissolves for preventing the run-out of the mainshaft, and the bearing can therefore lengthen its life.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] This invention aims to eliminate the gap between the housing and the outer ring of the bearing in order to maintain the roughness accuracy of the cutting surface in machine tools such as lathes that rotate the main shaft such as screw cutting machines. This invention relates to a device for preventing runout.

0002

[Prior art] Oil well steel pipes were connected using a coupling with a threaded section cut into the end of the pipe, but in recent years there has been an increase in the number of types that use metal touch sealing, such as special joints. , maintaining the accuracy of the surface finish roughness of the seal part is an issue.

The spindle of a machine tool such as a lathe that rotates the spindle, such as a screw cutting machine, supports the tool or workpiece at the center position with the required precision and rigidity while being affected by cutting force, driving torque, etc. It is an important element that rotates and provides main motion. In order to maintain the roughness accuracy of the cutting surface of a machine tool, it is necessary to suppress the runout of the machine tool's main axis as much as possible. Runout of the main shaft of a machine tool can be prevented by eliminating the gap in the bearing, and conventionally, the gap in the bearing is suppressed by eliminating the gap in the bearing and applying preload.

[0004] However, while the main shaft and the inner ring of the bearing are usually fixed by an interference fit, the outer ring of the bearing and the housing are usually loosely fitted to avoid creating a gap in the radial direction. I can't.

[0005]

[Problems to be Solved by the Invention] Conventionally, the radial gap that occurs between the outer ring and housing of a bearing whose inner ring is tightly fitted to the main shaft of a machine tool has been eliminated by preloading the bearing and expanding the outer ring of the bearing. was. However, the outer ring diameter of the bearing varies from one bearing to another by the width of the dimensional tolerance, and in the case of bearings near the lower limit of the dimensional tolerance, the gap cannot be eliminated unless a considerable preload is applied. Furthermore, it is difficult to control the preload of the bearing, and if the bearing deteriorates over time, the preload may be lost, and if the preload is applied too much, the bearing may burn out.

An object of the present invention is to provide a machine tool spindle run-out eliminating device that can completely eliminate the gap that occurs between the outer ring of the bearing and the housing, which causes run-out of the machine tool spindle.

[0007]

[Means for Solving the Problem] As a result of various studies to achieve the above object, the inventors of the present invention have determined that the gap between the outer ring and the housing of a bearing whose inner ring is closely fitted to the main shaft of a machine tool is We have discovered that this problem can be solved by inserting a sleeve that expands in the direction, and have arrived at this invention.

That is, the present invention provides a sleeve whose wall on the main shaft bearing side is elastically deformable with a gap wide in the axial direction and thin in the circumferential direction between the main shaft bearing and the housing of the machine, and the sleeve and the housing are tightly closed. This is a device for eliminating runout of a mechanical main shaft, which is formed by inserting a sleeve and a main shaft bearing with a loose fit, providing a communication hole that communicates with the gap in the sleeve, and connecting a pressurized fluid supply pipe.

[0009] Furthermore, a sleeve is inserted between the main shaft bearing and the housing of the machine with a gap that is wide in the axial direction and thin in the circumferential direction, and the wall on the main shaft bearing side and the wall on the housing side are elastically deformable, with a loose fit. , is a device for eliminating runout of a machine main shaft, which is formed by providing a communication hole communicating with a gap in a sleeve and connecting a pressurized fluid supply pipe.

0010

[Operation] According to the device of the present invention, when pressurized fluid is pressurized through the communication hole into the gap in the sleeve inserted between the main shaft bearing and the housing, the wall on the bearing side across the gap in the sleeve is elastically deformed. The bearing side wall contacts the bearing outer ring. This eliminates the gap between the loosely fitted sleeve and the main shaft bearing.

Furthermore, if pressurized fluid is pressurized through the communication hole into the gap in the sleeve inserted between the main shaft bearing and the housing, both the wall on the bearing side and the wall on the housing side across the gap in the sleeve will become elastic. It deforms and expands, and the wall on the bearing side contacts the outer ring of the bearing, and the wall on the housing side contacts the housing. Therefore, the gaps that occur between the loosely fitted sleeve and the main shaft bearing and between the sleeve and the housing are eliminated, and vibration of the machine main shaft is prevented.

[0012] In this invention, in order to expand the sleeve by filling the gap in the sleeve with pressure fluid, the bearing is mounted on the main shaft with an appropriate preload, and the relationship between the pressure fluid and the amount of deformation of the sleeve is determined in advance by testing. Once confirmed, the gap between the housing and the bearing outer ring can be completely eliminated by managing the fluid pressure.

[0013]

Embodiment 1 FIG. 1 is a longitudinal cross-sectional view of a main part of a main shaft bearing of a lathe in which the run-out eliminating device of the present invention is implemented, and FIG. 2 is an enlarged view of the main part of FIG. 1.

In FIGS. 1 and 2, 1 is the main shaft of the lathe, 2 is a free bearing with an inner ring 3 tightly fitted onto the main shaft 1, and 4 is a fixed bearing with an inner ring 5 tightly fitted onto the main shaft 1. It is. The fixed side bearing 4 is fixed in the axial direction by a fixing member 6. Further, the free side bearing 2 is free in the axial direction in order to absorb the thermal expansion of the main shaft 1.

Sleeves 11 and 12 are inserted into the housings 9 and 10 between the outer rings 7 and 8 of the bearings 2 and 4 and the housings 9 and 10 with a tight fit, and bolts (not shown) are passed through the flanges of the housings 9 and 10, respectively. , fixed at 10. The sleeves 11 and 12 are wide in the direction of the main axis 1 and have thin gaps 13 and 14 in the circumferential direction.
The outer rings 7 of the bearings 2 and 4 are placed across the gaps 13 and 14 of the bearings 2 and 4.
, 8 side walls 15 and 16 are housing 9 and 10 side walls 17
, 18, and is configured to be easily elastically deformable.

The sleeves 11 and 12 have a gap 13,
Communication holes 19 and 20 leading to the communication hole 14 are bored, and the communication hole 19
, 20 are connected to a connecting pipe 21 that is connected to a pressurizing device (not shown), and the fluid pressurized by the pressurizing device is connected to the connecting pipe 2.
1 so that it can be sealed into the spaces 13 and 14 from the communicating holes 19 and 20. In addition, 22 is a gear, and 23 is a jet lubricating device.

Since the configuration is as described above, if pressurized fluid pressurized by a pressurizing device (not shown) is first injected into the fixed side sleeve 12 through the connecting pipe 21 and into the connecting hole 20 and the gap 14, the sleeve 12 is heated. The wall 16 is elastically deformed and expanded, and the outer ring 8 of the bearing 4 is fixed. After that, when the main shaft 1 is sufficiently warmed by a trial run and has expanded sufficiently in the axial direction, pressurized fluid is injected into the free side sleeve 11 through the connecting pipe 21 into the connecting hole 19 and the gap 13.
The wall 15 of the bearing 2 elastically deforms and expands, and the outer ring 7 of the bearing 2
is fixed. As a result, the gap in the radial direction of the main spindle 1 is completely eliminated, run-out is prevented, and highly accurate cutting becomes possible.

When the cutting operation is completed, the temperature of the main shaft 1 gradually decreases, so that the connecting hole 1 of the sleeve 11 on the free side
9. The pressure of the pressurized fluid sealed in the gap 13 is released, and the expansion of the wall 15 of the sleeve 11 is released to create a gap between the outer rings of the bearing 2 so that the contraction of the main shaft 1 can be absorbed. Therefore, the connection hole 19 on the free side, the gap 1
The pressure of the pressure fluid sealed in the main shaft 1 can be adjusted by measuring the temperature of the main shaft 1 and automatically increasing or decreasing the pressure based on the measurement result.

Embodiment 2 FIG. 3 is an enlarged view of main parts showing another embodiment of the present invention, in which a sleeve 36 is inserted between the outer ring 34 of a bearing 33 in which the inner ring 32 is tightly fitted to the main shaft 31 and the housing 35. do. This sleeve 36 is wide in the axial direction of the main shaft 31 and has a thin gap 37 in the circumferential direction, and a wall 38 on the outer ring 34 side of the bearing 33 and a wall 39 on the housing 35 side with the gap 37 of the sleeve 36 in between are as follows: The structure is thin so that it can be elastically deformed.

A communication hole 40 communicating with the cavity 37 is bored in the sleeve 36, and a connecting pipe 41 connected to a pressurizing device (not shown) is connected to the communicating hole 40, and fluid pressurized by the pressurizing device is connected to the communicating hole 40. It is configured so that it can be sealed into the cavity 37 from the communication hole 40 via the connecting pipe 41.

By configuring as described above, gaps are provided between the housing 35 and the sleeve 36 and between the sleeve 36 and the outer ring 34 of the bearing 33 to facilitate assembly, and the sleeve 36 and the bearing 33 are assembled into the housing 35. Then, when pressurized fluid is sealed into the communication hole 40 and the gap 37 via the connecting pipe 41, the walls 38 and 39 of the sleeve 36 are elastically deformed and expanded in the radial direction, so that the walls 38 and 39 are attached to the outer ring 34, respectively. Wall 39 contacts housing 35 . Therefore, the radial gap between the bearing 33 and the housing 35 is eliminated,
This makes it possible to prevent the main shaft 31 from wobbling.

[0022]

[Effects of the Invention] As described above, according to the device of the present invention, the gap between the bearing and the housing can be completely eliminated by interposing an elastically deformable sleeve between the bearing of the main shaft of the machine and the housing. , it is possible to prevent the spindle from wobbling. Furthermore, since bearings can be used with proper preload, burnout caused by excessive preload and gaps caused by insufficient preload can be eliminated, and the life of the bearing can be extended.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal cross-sectional view of a main part of a lathe in which a backlash eliminating device of the present invention is implemented in a main shaft bearing portion of a lathe.

FIG. 2 is an enlarged view of main parts on the fixed side of FIG. 1;

FIG. 3 is an enlarged view of main parts showing another embodiment of the invention.

[Explanation of symbols]

1, 31 Main shaft 2, 4, 33 Bearing 3, 5, 32 Inner ring 6 Fixing member 7, 8, 34 Outer ring 9, 10, 35 Housing 11, 12, 36 Sleeve 13, 14, 37 Gap 15, 16, 17, 18 , 38, 39 wall 19, 20
, 40 communication holes 21, 41 connecting pipe 22 gear 23 jet lubrication device

Claims (2)

[Claims] Claim 1: A sleeve whose wall on the main shaft bearing side is elastically deformable is tightly fitted between the main shaft bearing and the housing of the machine, with a gap wide in the axial direction and thin in the circumferential direction, the sleeve being tightly fitted between the sleeve and the housing, A device for eliminating runout of a machine spindle, which is formed by inserting a sleeve and a spindle bearing with a loose fit, providing a communication hole that communicates with the gap in the sleeve, and connecting a pressurized fluid supply pipe. [Claim 2] A sleeve is inserted between the main shaft bearing and the housing of the machine with a gap that is wide in the axial direction and thin in the circumferential direction, and the wall on the main shaft bearing side and the wall on the housing side are elastically deformable, with a loose fit. A device for eliminating runout of a machine main shaft, which is formed by providing a communication hole that communicates with a gap in a sleeve and connecting a pressurized fluid supply pipe.