JPH11336754A - Preload device for bearing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a preload device for a bearing capable of controlling the preload of the bearing without using an auxiliary driving means such as a fluid pressure supply means. SOLUTION: This preload device for bearing 2, in which inner ring spacers 3 and outer ring spacers 9 are disposed alternately in a housing 4 and supports a rotating shaft 1, includes a flange 5 fixed on one end of the housing 4, a bearing cover 7 fixed at one end of the housing 4, a bearing cover 7 supported at the other end so as to be capable of moving in the axial direction, and a bellows-type leaf spring 10 formed so that its inner periphery may touch the outer peripheries of the bearing 2 and the outer ring spacer 9 and both ends in the axial direction may touch the flange 5 and the bearing cover 7.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a preloading device for a bearing that supports a rotating shaft such as a main shaft of a machine tool.
The present invention relates to a bearing preloading device suitable for supporting a rotating shaft used in a wide rotation range from low-speed rotation to high-speed rotation.

[0002]

2. Description of the Related Art In general, a rotary shaft such as a main shaft of a machine tool is required to be machined at a rotational speed of several hundred rpm to 20,000 rpm or more. Rotation from such a low-speed rotation region to an ultra-high-speed rotation region is required.

[0003] When the rotation speed of the rotating shaft is higher than 10,000 rpm, heat generation of the bearings and the motor becomes remarkable, and thermal expansion of the rotating shaft also increases. When the rotating shaft extends in the axial direction due to thermal expansion, the position of the inner ring of the bearing fixed to the rotating shaft also changes. On the other hand, the housing that supports the rotating shaft is less affected by the heat generated by the heat generated by the bearings and the motor, so that the elongation in the axial direction is small. For this reason,
When the rotating shaft rotates at a high speed, the relative position between the inner race and the outer race of the bearing is shifted, and the preload of the bearing is increased. In the worst case, the bearing is burned.

[0004] As a device capable of adjusting the preload of such a bearing, a bearing preload device disclosed in Japanese Patent Application Laid-Open No. 4-146004 has been proposed. In this device, a pressure space is formed between a housing supporting a bearing and an outer ring spacer, and the pressure space is connected to a fluid pressure supply source. Then, a fluid pressure is supplied to the pressure space to elastically deform the outer race spacer in its radial direction, thereby changing the axial length to adjust the preload of the bearing.

[0005] With this configuration, the preload of the bearing can be adjusted without reducing the axial rigidity of the rotating shaft.

[0006]

However, such a preloading device for a bearing requires fluid pressure supply means for supplying fluid pressure, which not only complicates the device but also increases the fluid pressure supply means. Regular maintenance is required, and management becomes complicated.

SUMMARY OF THE INVENTION In view of the above circumstances, an object of the present invention is to provide a bearing preload device that can control the preload of a bearing without using auxiliary driving means such as fluid pressure supply means.

[0008]

In order to achieve the above object, according to the first aspect of the present invention, an inner ring spacer and an outer ring spacer are alternately arranged in a housing to support a rotating shaft. In a bearing preloading device, a flange fixed to one end of the housing, a bearing cover supported at the other end so as to be movable in an axial direction, an outer periphery is in contact with an inner periphery of the housing, and an inner periphery is the bearing and an outer ring. A bellows-shaped leaf spring was provided so as to be in contact with the outer periphery of the spacer and to have both ends in the axial direction thereof in contact with the flange and the bearing cover.

Further, in the invention according to claim 2,
In a preloading device for a bearing which alternately arranges an inner ring spacer and an outer ring spacer in a housing and supports a rotating shaft, a bearing fixed to one end of the housing and a bearing supported movably in the axial direction at the other end. The cover, a groove parallel to the axis of the rotating shaft is formed alternately from the front end side and the rear end side, the inner periphery of which is in contact with the outer periphery of the bearing and the outer ring spacer, and the outer periphery is the inner periphery of the housing. A bellows-shaped leaf spring is provided so that the inner periphery thereof is in contact with the sleeve, and both ends in the axial direction thereof are in contact with the flange and the bearing cover.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a side sectional view of a bearing preload device showing a first embodiment of the present invention.

In FIG. 1, reference numeral 1 denotes a rotating shaft. 2 is a bearing
The inner ring 2a is composed of an inner ring 2a, rolling elements (steel balls) 2b, and an outer ring 2c. Reference numeral 4 denotes a housing whose inner peripheral surface has a diameter of the bearing 2.
Is formed to be larger than the outer diameter of the outer ring 2c. A flange 5 is fixed to one end of the housing 4 with a bolt 6a.

A bearing cover 7 is movably supported by the other end of the housing 4 with a bolt 6b via a flat spring 8. Reference numeral 9 denotes an outer ring spacer, which is disposed between the outer rings 2c of the bearing 2. 10 is a leaf spring formed in a cylindrical bellows shape,
The outer periphery is in contact with the inner peripheral surface of the housing, and the inner periphery is arranged to be in contact with the outer peripheral surface of the outer ring 2c of the bearing 2 and the outer ring spacer 9, and both ends thereof are in contact with the flange 5 and the bearing cover 7.

Reference numeral 11 denotes a nut, which is screwed to one end of the rotating shaft 1, and fixes the inner ring 2 a of the bearing 2 to the rotating shaft 1 via a collar 12.

With such a configuration, the bearing 2
Is restrained by a leaf spring 10 and the axial direction is restrained by a flange 5 and a bearing cover 7. When the rotating shaft 1 is rotated in a high-speed rotation region, the rotating shaft 2 expands due to heat generated by friction of the bearing 2 and heat generated by a motor that drives the rotating shaft.

The bearing 2 also thermally expands simultaneously with the thermal expansion of the rotating shaft 1. In addition to the thermal expansion, the outer ring 2c of the bearing 2 receives the centrifugal force of the rolling element 2b to increase the outer diameter. .
The displacement of the outer diameter of the outer ring 2c presses the leaf spring 10 against the housing 4 and acts in a direction to crush the unevenness, thereby extending the leaf spring 10 in its axial direction.

At this time, the bearing cover 7 moves in the axial direction of the rotary shaft 1 due to the relationship between the extension force of the leaf spring 10 and the spring force of the flat spring 8. Therefore, by setting the spring constant of the flat spring 8 so as to match the displacement due to the thermal expansion of the rotating shaft 2 during high-speed rotation, the displacement of the inner ring 2a of the bearing 2 due to the thermal expansion of the rotating shaft 2 and the outer ring 2c And the preload applied to the bearing 2 can be constantly maintained constant.

FIGS. 2 and 3 show a second embodiment of the present invention. FIG. 2 is a side sectional view of a bearing preloading device, and FIG. 3 is a perspective view of a sleeve in FIG. . In the figure, the same components as those in FIG. 1 are denoted by the same reference numerals. Reference numeral 13 denotes a sleeve, as shown in FIG. 3, in which grooves 13a are alternately formed at predetermined intervals from both ends in the axial direction, and as shown in FIG. It is mounted between the inner circumferences of the leaf spring 10.

With such a configuration, a plurality of (four in FIG. 2) bearings 2 arranged at intervals can be substantially one bearing, and the amount of displacement in the radial direction can be reduced. It can be transmitted to the leaf spring 10 reliably.

Since there may be a gap between the outer circumference of the outer race spacer 9 and the inner circumference of the sleeve 13, the outer diameter of the outer race spacer 9 can be easily manufactured.

[0020]

As described above, according to the present invention, in a preloading device for a bearing which supports a rotating shaft and is alternately arranged in a housing with an inner ring spacer and an outer ring spacer, the preloading device is fixed to one end of the housing. A flange, a bearing cover supported at the other end so as to be movable in the axial direction, an outer periphery in contact with the inner periphery of the housing, an inner periphery in contact with the outer periphery of the bearing and the outer ring spacer, and both ends in the axial direction. Provided a bellows-shaped leaf spring formed so as to be in contact with the flange and the bearing cover, so that the preload of the bearing is adjusted to an appropriate state in accordance with the rotation speed of the rotating shaft without using auxiliary driving means. Can be adjusted.

Further, in a preloading device for a bearing which alternately arranges an inner ring spacer and an outer ring spacer in a housing and supports a rotating shaft, a flange fixed to one end of the housing and an axially movable member at the other end. The bearing cover is supported by, a groove is formed alternately from the front end side and the rear end side parallel to the axis of the rotating shaft, the inner circumference of which is in contact with the outer circumference of the bearing and the outer ring spacer, and the outer circumference is In contact with the inner circumference of the housing,
A bellows-shaped leaf spring is formed so that the inner periphery is in contact with the sleeve and both ends in the axial direction are in contact with the flange and the bearing cover. The preload of the bearing can be smoothly adjusted to an appropriate state in accordance with the rotation speed of the bearing.

[Brief description of the drawings]

FIG. 1 is a side sectional view of a bearing preload device according to a first embodiment of the present invention.

FIG. 2 is a side cross-sectional view of a bearing preload device according to a second embodiment of the present invention.

FIG. 3 is a perspective view of a sleeve in FIG. 2;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Rotating shaft, 2 ... Bearing, 2a ... Inner ring, 2b ... Rolling element, 2
c ... outer ring, 3 ... inner ring spacer, 4 ... housing, 5 ... flange, 6a, 6b ... bolt, 7 ... bearing cover, 8 ... flat spring, 9 ... outer ring spacer, 10 ... leaf spring, 13 ... sleeve.

Claims (2)

[Claims] 1. A preloading device for bearings which alternately has inner and outer race spacers in a housing and which supports a rotating shaft, wherein the flange is fixed to one end of the housing and is axially movable to the other end. Formed so that the outer periphery is in contact with the inner periphery of the housing, the inner periphery is in contact with the outer periphery of the bearing and the outer ring spacer, and both ends in the axial direction are in contact with the flange and the bearing cover. A preloading device for a bearing, characterized in that a bellows-shaped leaf spring is provided. 2. A preloading device for bearings which alternately arranges inner ring spacers and outer ring spacers in a housing and supports a rotating shaft, wherein the flange is fixed to one end of the housing and is axially movable to the other end. The bearing cover is supported by, a groove is formed alternately from the front end side and the rear end side parallel to the axis of the rotating shaft, the inner circumference of which is in contact with the outer circumference of the bearing and the outer ring spacer, and the outer circumference is A bearing having a bellows-shaped leaf spring which is in contact with the inner periphery of the housing, the inner periphery is in contact with the sleeve, and both ends in the axial direction thereof are in contact with the flange and the bearing cover. Preload device.