JPH11201173A - Rolling bearing for high speed rotation - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate a fear of precision change and sticking occurring. SOLUTION: This bearing comprises inner and outer rings 2 and 1; and a ball 3 making rolling contact with the raceway ring. Rolling friction between the raceway ring and the rolling body is lubricated by feeding oil a gap between the inner and outer rings and discharge of the oil. A taper having diameter gradually increasing toward the oil discharge end face side is formed on the shoulder part 12 of the inner ring on the side, where oil is discharged.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rolling bearing, and more particularly to a rolling bearing suitable for supporting a high-speed rotating shaft such as a main shaft of a machine tool.

[0002]

2. Description of the Related Art Conventionally, as one of such rolling bearings, there is an angular ball bearing as shown in FIG. The bearing has a configuration in which a rolling element 3 is interposed between an inner ring 2 and an outer ring 1 which are race rings, and the rolling element is rotatably held between the inner ring 2 and an outer ring by a retainer 4. I have.

[0003] Friction at the rolling contact surface between the bearing ring and the rolling element is lubricated by oil or grease. Rolling bearings using lubricating grease include those in which grease is sealed in the bearing in advance and those in which the outside of the bearing is shut off with a sealing plate. On the other hand, as shown in FIG. There are rolling bearings used in lubricated systems that are supplied from one end face of the bearing, usually the back side in the case of angular ball bearings, and are discharged from the other end face of the bearing. The rolling bearing is used to support a high-speed rotating shaft such as a main shaft of a machine tool.

The main spindle of a machine tool, a magnetic drum for an electronic computer, a dental spindle, a high-frequency spindle for internal grinding, a bearing for a jet engine, and the like are required to rotate at a high speed of about 10,000 or more per minute. .

[0005] Such rolling bearings for high-speed rotation include:
In order to achieve and maintain good lubrication, a lubrication system of a type in which a lubricant is supplied from the outside into a bearing is used. In particular, in recent years, a system has been realized in which a lubricant is forcibly supplied from the outside of the bearing to the inside of the bearing by an oil jet, an oil mist, oil air, or the like to lubricate the inside of the bearing.

[0006]

In the above-described rolling bearing for high-speed rotation, when the lubricant stays in the bearing, the bearing generates heat due to a stirring resistance when the lubricant is stirred, and the bearing ring constituting the bearing is formed. In addition, there is a problem that the rolling elements thermally expand and the accuracy of the bearing changes, and the possibility of seizure increases.

In order to solve this problem, it is desirable to discharge the lubricant to the outside of the bearing as soon as the bearing rotates at a high speed. However, in a conventional rolling bearing, this is sufficiently considered. Did not.

Accordingly, the present invention provides a lubrication system which supplies a lubricant from the outside into a bearing under high-speed rotation.
It is an object of the present invention to provide a rolling bearing that is free from a change in accuracy or a seizure due to heat generated by the stirring resistance of a lubricant.

[0009]

In order to achieve this object, the present invention relates to a rolling bearing having a plurality of rolling elements interposed between an outer race and an inner race. Means for supplying a lubricant from the outside and lubricating the lubricant by sequentially discharging the supplied lubricant, and for urging the flow of the lubricant toward the lubricant discharge side of the raceway. Is provided.

Therefore, according to the present invention, the flow of the lubricating oil itself or the air containing the oil is formed or promoted toward the lubricant discharge end face side of the bearing.
Even if the bearing is used under high-speed rotation, the lubricant is quickly discharged to the outside of the bearing. As a result, the rolling bearing for high-speed rotation has no risk of precision change or seizure due to heat generated by the stirring resistance of the lubricant. Can be provided.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In one embodiment of the present invention,
The means described above is constituted by at least one of the inner ring and the outer ring, which are the race rings, having a region facing the flow of the lubricant in the bearing, which is shaped to increase the peripheral speed when the race ring rotates. Preferably, the rotational peripheral speed is increased toward the lubricant discharge side end face of the rolling bearing.

The above-mentioned area in which this means is realized is adjacent to or continuous with the raceway groove on which the rolling element rolls.
It is the shoulder of the race of the inner race or the outer race.

One example of a means for promoting the flow of lubricant discharge is to form the shoulder of the raceway groove of the inner race such that its diameter increases toward the inner race end face on the lubricant discharge side. Another example is a counter bore bearing in which the diameter of the inner peripheral surface of the outer ring increases as the diameter of the inner peripheral surface approaches the end surface of the outer ring on the lubricant discharge side. The bearing of the present invention may be any of an angular ball bearing, a deep groove ball bearing, and a roller bearing.

The shape of the shoulder described above is not particularly limited as long as it has desired characteristics such as a tapered shape and a curved shape along the flow of the lubricant. Preferably, a curved shape is preferable because the flow of discharge is smooth.

[0015]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. FIG. 2 shows a partial sectional view of an angular contact ball bearing to which the present invention is applied. In the following description of the figures,
The same parts as those in FIG. 1 are denoted by the same reference numerals, and description thereof will be omitted.

In FIG. 2, oil air and the like as a lubricant are supplied to an outer ring 1 and an inner ring 2 in the same manner as indicated by arrows in FIG.
Are sequentially supplied from the lubricant supply side (right side in the figure),
Then, the lubricant is sequentially discharged from the lubricant discharge side (left side in the figure).

A shoulder portion 12 which is continuous with and adjacent to the raceway groove 10 of the inner race extends toward the end surface of the inner race of the lubricant discharge side.
It is formed to have a tapered shape in which the diameter (L) from the center line M to the outer periphery of the inner ring is gradually increased at a constant ratio (the ratio is predetermined). The leading edge of the shoulder 12 on the lubricant discharge side is:
Beveled. Note that this ratio may be appropriately determined depending on the lubrication conditions.

When the inner ring 2 of the rolling bearing rotates, the peripheral speed during rotation increases at a constant rate in a region where the diameter of the shoulder portion 12 is large, and a large centrifugal force is generated. This centrifugal force increases toward the lubricant discharge end face. That is, a peripheral speed difference occurs during rotation between the shoulder 12 and the other inner ring.

A gap 4 for supplying lubricant, oil, oil jet, oil mist, and oil air is provided between the outer ring 1 and the inner ring 2 on the lubricant supply side and the retainer 4.
0 is formed. On the other hand, a similar gap 42 for discharging the oil is formed on the oil discharge side. That is, the oil supplied between the outer ring 1 and the inner ring 2 is supplied to the ball 3 through the gap 40. On the other hand, excess oil is discharged to the outside of the bearing through the gap 42 as the inner and outer rings and the rolling elements rotate.

Since the shoulder 12 itself is separated from the rolling elements and exposed to the flow of the lubricant, the velocity of the flow of the lubricant or air near the shoulder is directed toward the inner ring end face on the lubricant discharge side. In other words, a kind of pump action is realized, in which the pressure and the pressure are sequentially increased, in other words, this is urged or accelerated, and the air and the lubricant flow toward the outside (discharge side) of the bearing.

As a result, the lubricant and the air are satisfactorily discharged from the discharge side (left side in the figure) of the bearing, and excess lubricant and unnecessary lubricant are also efficiently discharged. However, heat generation due to the stirring resistance of the bearing lubricant is prevented.

Therefore, the rotational performance of the bearing is improved, and the influence of thermal strain due to excessive heat generation of the bearing on peripheral devices and devices of the bearing such as a machine tool can be prevented.
As the bearing is used under higher rotation speed, the rotation peripheral speed of the shoulder portion 12 is increased, so that the discharge speed of lubricant, air, mist, etc. is increased, and the cooling performance of the bearing is increased. It is further advantageous because it is improved at the same time.

The angular ball bearing shown in FIG. 2 has a counter bore outer ring 14 in which the width of the outer ring 1 tends to be removed toward the lubricant discharge side. Since the inner diameter of the counter bore outer ring 14 from the center line M to the inner peripheral surface of the outer ring tends to increase toward the end surface of the lubricant discharge side outer ring, the inner surface of the counter bore outer ring facing the lubricant has a tendency to increase. The peripheral speed increases toward the lubricant discharge side. Therefore, the counterbore outer ring 14, in combination with the shoulder 12 of the inner ring, increases the speed at which the lubricant and the like are discharged.

FIG. 3 et seq. Show another example of a rolling bearing to which the present invention is applied. FIG. 3 shows a deep groove ball axis. FIG. 4 shows a roller bearing. In each case, a shoulder portion 12 having the same shape as that of FIG. 2 is formed.

In FIG. 5, instead of the shoulder 12 having a tapered shape, a curved shape along the air flow or the like (a streamlined shape having an inflection point in the middle) is shown. By adopting this shape, the resistance given to the fluid such as the lubricant is reduced, and the oil discharging ability when the lubricant is discharged to the outside of the bearing is improved.

1 to 5 show that the lubricant is supplied from the outside into the bearing by oil air or the like, whereas FIG. 6 shows the oil between the inner wall on the inner ring 2 side and the oil between the inner and outer rings. This shows a form in which an underrace 60 for supplying lubricant is provided up to the supply path, and oil is supplied via this underlace. This type of rolling bearing also achieves the same effects as the bearings of FIGS. 2 to 5.

The shape given to the shoulder 12 may be a two-stage taper or a tapered or curved part of the shoulder instead of the taper or curve described above. .

[0028]

As described above, according to the present invention,
It is possible to provide a rolling bearing for high-speed rotation that does not cause a change in accuracy or a seizure.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view in a direction orthogonal to the outer peripheral direction of a conventional angular ball shaft.

FIG. 2 is a sectional view of an angular ball bearing to which the present invention is applied.

FIG. 3 is a sectional view of a deep groove ball bearing to which the present invention is applied.

FIG. 4 is a sectional view of a roller bearing to which the present invention is applied.

FIG. 5 is a sectional view of a deep groove ball bearing having a curved surface formed on a shoulder.

FIG. 6 is a sectional view of a deep groove ball bearing in which an underrace is formed as a lubrication mechanism.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Outer ring 2 Inner ring 3 Rolling element 4 Cage 10 Track groove 12 Shoulder part 60 Underrace

Claims (1)

[Claims] In a rolling bearing having a plurality of rolling elements interposed between a raceway of an outer race and a raceway of an inner race, a lubricant is externally supplied between the races, and the supplied lubricant is dispersed between the races. A rolling bearing for high-speed rotation, wherein the rolling bearing is configured to be lubricated by discharging sequentially, and means for biasing the flow of the lubricant is provided on the lubricant discharging side of the race.