JP2018168953A - Holder for rolling bearing and rolling bearing with outer ring oil supply hole - Google Patents

Abstract

To provide a holder for rolling bearing and a rolling bearing with an outer ring oil supply hole, capable of greatly reducing noise occurring from outer ring oil supply, with a simple structure.SOLUTION: This invention relates to a rolling bearing with an outer ring oil supply hole that has an oil supply hole opened within a range of an axial width W of a rolling body 3 on an inner peripheral surface of an outer ring 2, and a holder thereof, and they are, for example, applied to an angular contact ball bearing. An outer diameter of a holder 4 has a larger outer diameter D2 at an end part of a drainage side than an outer diameter D1 at a bearing width center part. Dimensional relation preferably shows (D2/2)-(D1/2)<0.20×rolling body diameter Dw.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a rolling bearing retainer used for a rolling bearing with an outer ring oil supply hole, and a rolling bearing with an outer ring oil supply hole using the same.

Air-oil lubrication is frequently used for angular contact ball bearings for machine tool main spindles in order to ensure lubrication reliability during high-speed rotation. In recent machine tools, the spindle length is made as short as possible to reduce the size and improve the critical speed and the spindle rigidity. Against this background, the adoption of “rolling bearings with outer ring oil supply holes” in which an air oil lubrication supply nozzle is provided on the outer ring is increasing.
FIG. 3 shows an example thereof, and an oil supply hole 6 for discharging the air oil is provided at a position slightly away from the raceway surface 2 a toward the counter bore 5 on the inner peripheral surface of the outer ring 2.

  In addition to the above, rolling bearings with outer ring lubrication holes have the advantages of high lubrication reliability and low usage of compressed air and lubricating oil. On the other hand, since the accompanying air layer (air curtain) formed around the revolving rolling element and the air oil directly collide with each other, the problem is that the collision noise (noise) is large.

  As a method for solving this problem, for example, in Patent Document 1, a circumferential groove and an oil supply hole are provided on the outer diameter of the outer ring, and a cross-sectional area ratio between the groove and the oil supply hole is defined within a specific range. As a result, a restriction is applied to the flow path, the flow rate of the compressed air pressure at the outlet of the oil supply hole is lowered while maintaining a certain level of compressed air pressure, and noise is reduced.

JP 2013-79711 A

  The countermeasure of Patent Document 1 is to restrict the cross-sectional area ratio between the circumferential groove of the outer diameter of the outer ring and the oil supply hole to a specific range and to restrict the flow path, but it is difficult to obtain the effect of the restriction sufficiently, Further noise reduction is desired.

  An object of the present invention is to provide a rolling bearing retainer and a rolling bearing with an outer ring oil supply hole in which a reduction in noise caused by outer ring oil supply is greatly obtained with a simple configuration.

  The cage for a rolling bearing according to the present invention is a rolling bearing having an oil supply hole opened in a range within the axial width of the rolling element on the inner peripheral surface of the outer ring, and the outer diameter of the cage is the center of the bearing width. The outer diameter at the end portion on the oil drain side is larger than the outer diameter at the center of the axial width.

  According to this configuration, since the outer diameter of the cage on the oil drain side is larger than the outer diameter of the cage at the center of the bearing width, the space between the outer ring inner diameter and the outer diameter of the cage can be narrowed at that point. it can. Thereby, the throttle part can be provided in the bearing internal space, the flow rate of the compressed air pressure is lowered, and the noise is reduced. The end on the oil drain side is the end with the wider space between the cage and the outer ring. In the case of an angular ball bearing, it is the end on the front side of the bearing, and in the case of a deep groove ball bearing, the ends on both sides. Part.

In the present invention, the lubricating oil discharged from the oil supply hole may be a lubricating oil with a small amount of lubrication conveyed by compressed air. For example, air oil or oil mist is used as the micro lubrication to be conveyed by compressed air.
This type of micro lubrication is excellent in terms of ensuring the reliability of lubricity during high-speed rotation, but the noise problem is significant. For this reason, the effect of the reduction of the flow velocity of compressed air pressure obtained by enlarging the outer diameter surface of the cage end and noise reduction is great.

In this invention, the rolling bearing is an angular contact ball bearing having a counter bore in the outer ring, and the end portion where the outer diameter of the cage is large is the end portion on the bearing front side, that is, the end portion on the counter bore side. It may be.
In the case of an angular contact ball bearing having a counter bore in the outer ring, the clearance between the outer peripheral surface of the cage and the inner peripheral surface of the outer ring is large. The effect of reducing the flow rate of compressed air and reducing noise is great.

For this configuration,
(Outer diameter of cage at front end of bearing) / 2-(Outer diameter of cage at center of bearing width) / 2
<0.20 × rolling element diameter may be sufficient. Note that multiplication by 1/2 indicates a difference in radius.
As described above, the outer diameter of the cage front side end portion is increased to reduce the flow rate of the compressed air pressure, but if it is too large, the space becomes too narrow and the oil drainage of the lubricating oil decreases. In addition, excessive temperature rise may occur due to the stirring resistance of the lubricating oil.
As described above, when the radial difference between the outer diameter of the cage at the front end of the bearing and the outer diameter of the cage at the center is less than 0.20 times the rolling element diameter, the space does not become too narrow. This prevents the oil drainage of the lubricating oil from being lowered. The size of the space also affects the size of the counterbore, but if it is less than 0.20 times the rolling element diameter, it matches the size of the counterbore formed by a normal design.

A rolling bearing with an outer ring oil supply hole of the present invention is a bearing having the cage according to any one of the above aspects of the present invention.
According to the bearing having this configuration, the noise reduction effect described for the cage of the present invention can be obtained.

  The cage for a rolling bearing according to the present invention is a rolling bearing having an oil supply hole that opens in a range within the axial width of the rolling element on the inner peripheral surface of the outer ring, and the outer diameter of the cage is at the center portion of the bearing width. Since the outer diameter at the end portion on the oil drain side is larger than the outer diameter, a reduction in noise caused by the outer ring oil supply can be greatly obtained with a simple configuration.

  Since the rolling bearing with the outer ring oil supply hole of the present invention has the cage described in any one of the above aspects of the present invention, a reduction in noise caused by the outer ring oil supply can be greatly obtained with a simple configuration.

It is sectional drawing which shows the half part of the rolling bearing with an outer ring oil supply hole which concerns on 1st Embodiment of this invention. It is sectional drawing which shows the half part of the rolling bearing with an outer ring oil supply hole which concerns on other embodiment of this invention. It is sectional drawing of a prior art example.

  A first embodiment of the present invention will be described with reference to FIG. This figure is a cross-sectional view showing a half part of a rolling bearing with an outer ring oil supply hole. This rolling bearing with an outer ring oil supply hole is used for supporting a spindle of a machine tool, an industrial machine, or the like. This rolling bearing with an outer ring oil supply hole is an angular ball bearing in which a plurality of rolling elements 3 made of balls are interposed between raceway surfaces 1 a and 2 a of an inner ring 1 and an outer ring 2, and these rolling elements 3 are held by a cage 4. It is. The raceway surfaces 1 a and 2 a are provided so that a contact angle θ is generated, and a counter bore 5 is formed on the inner peripheral surface on the front side of the outer ring 2. The shape of the counterbore 5 is a tapered shape in which the bearing end side is gradually deepened in the illustrated example, but may be a shape having a constant depth.

  The outer ring 2 is provided with oil supply holes 6 opened on the inner peripheral surface at one to several places in the circumferential direction, for example, two places opened in the diameter direction. In this example, the oil supply hole 6 is provided at a location close to the raceway surface 2 a in the axial range of the counterbore 5. The position where the oil supply hole 6 opens on the inner peripheral surface of the outer ring 2 may be within the width of the rolling element 3 in the bearing axial direction, but is preferably outside the range where the contact ellipse is generated by the load. On the outer peripheral surface of the outer ring 2, circumferential grooves 7 and 7 are formed on both sides of the oil supply hole 6, and annular seal members 8 and 8 made of O-rings or the like are fitted in these circumferential grooves 7 and 7. . The outer ring 2 is fitted to the inner peripheral surface of the housing 9 via these seal members 8, and an annular sealed space is formed between the outer peripheral surface of the outer ring 2 and the inner peripheral surface of the housing 9. Through the oil supply path (not shown) in the housing 9 and the annular space, the oil supply hole 6 is fed with a small amount of lubricating oil conveyed by compressed air into an oil supply device (not shown). The lubricating oil conveyed by the compressed air is, for example, air oil or oil mist. Various rotary shafts (not shown) such as a main shaft of a machine tool are fitted to the inner periphery of the inner ring 1.

  The cage 4 is formed with circular pockets 10 penetrating inward and outward at a plurality of locations in the circumferential direction, and the rolling elements 3 are held in the pockets 10. The material of the cage 4 may be a metal or a synthetic resin. In this example, the cage 4 is an outer ring guide that is guided by the inner peripheral surface portion 2b on the back side of the outer ring 2. The shape of the outer peripheral surface of the cage 4 is such that the outer peripheral surface portion 4a closer to the bearing back side than the center in the bearing axial direction is a cylindrical surface having a constant outer diameter, so that the outer ring can be guided. The outer peripheral surface portion 4b on the counter bore 5 side of the outer peripheral surface of the cage 4 from the center in the bearing axial direction has a tapered shape that gradually increases in diameter toward the end of the axial width. The cage outer diameter D2 at the end is larger than D1. The counter bore 5 side has a large gap with the outer ring 2 and is not guided by the outer ring, and is on the oil drain side.

About the extent of increasing the cage outer diameter D2,
(Cage outer diameter D2 at the bearing front end) / 2- (Cage outer diameter D1 at the center of the bearing width) / 2 <0.20 × Rolling body diameter Dw (1)
It is said that.
In addition, the inner peripheral surface of the cage 4 has a cylindrical surface shape having a constant diameter over the entire axial direction.

According to this configuration, since the cage outer diameter D2 at the end on the oil drain side is larger than the cage outer diameter D1 at the center of the bearing width, the space S between the outer ring inner diameter and the cage outer diameter on the bearing front side is increased. Can be narrowed. As a result, the throttle portion can be provided in the bearing internal space, the flow rate of the compressed air pressure by the lubricating oil carrier air such as air oil discharged from the oil supply hole 6 is lowered, and noise is reduced.
However, if the outer diameter of the cage front side end portion D2 is too large, the space S becomes too narrow and the oil drainability of the lubricating oil is lowered, which may cause excessive temperature rise due to the stirring resistance of the lubricating oil. is there.
However, as shown by the equation (1), the radial difference between the cage outer diameter D2 at the bearing front side end and the cage outer diameter D1 at the center is less than 0.20 times the rolling element diameter Dw. Thus, the space S is not too narrow, and the oil drainage of the lubricating oil is prevented from being lowered. The radial range of the space S also affects the size of the counterbore 5, but if the size is less than 0.20 times the rolling element diameter, the size of the counterbore formed by a normal design It matches if there is.

  FIG. 2 shows another embodiment of the present invention. In this embodiment, the outer peripheral surface portion 4 b ′ on the bearing front side of the cage 4 has a stepped shape having a large diameter only from the vicinity of the pocket 10 to the end surface. The relationship of the formula (1) is the same in this embodiment.

  In the case of this embodiment as well, the flow rate of the compressed air pressure by the lubricating oil conveying air such as air oil discharged from the oil supply hole 6 is lowered, and noise is reduced, as in the above embodiment. Moreover, by having the dimensional relationship of said (1) Formula, it is prevented that the space S does not become narrow too much and the oil draining property of a lubrication element falls. Other configurations and effects in this embodiment are the same as those in the first embodiment.

  In addition, since this invention is a device in the cage 4 in the bearing space, it can be used in combination with a device for noise reduction outside the bearing. Moreover, although each said embodiment demonstrated about the case where all were applied to the angular ball bearing, this invention can be applied to a rolling bearing generally, for example, ball bearings, such as a deep groove ball bearing and a 4-point contact ball bearing Can also be applied effectively.

  As mentioned above, although the form for implementing this invention based on the Example was demonstrated, embodiment disclosed here is an illustration and restrictive at no points. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

DESCRIPTION OF SYMBOLS 1 ... Inner ring 1a ... Raceway surface 2 ... Outer ring 2a ... Raceway surface 3 ... Rolling element 4 ... Cage 5 ... Counter bore 6 ... Oil supply hole D1 ... Cage outer diameter D2 of bearing center part ... Cage outer diameter Dw of edge part ... Rolling element diameter

Claims (5)

A rolling bearing having an oil supply hole opening in a range within the axial width of the rolling element on the inner peripheral surface of the outer ring,
A cage for a rolling bearing in which the outer diameter of the retainer is larger at the oil drain side end than at the bearing width center.   The rolling bearing cage according to claim 1, wherein the lubricating oil discharged from the oil supply hole is a minute amount of lubricating oil conveyed by compressed air.   The rolling bearing retainer according to claim 1 or 2, wherein the rolling bearing is an angular ball bearing having a counter bore in an outer ring, and an end portion on the side where the outer diameter of the retainer is large Is a rolling bearing retainer which is an end portion on the counter bore side. A rolling bearing retainer according to claim 2,
(Outer diameter of cage at the front end of the bearing) / 2-(Outer diameter of cage at the center of bearing width) / 2
<Roller bearing cage with <0.20 × rolling element diameter.   The rolling bearing with an outer ring oil supply hole which has the cage for rolling bearings of any one of Claim 1 thru | or 4.

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