JP2006300079A - Roller bearing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a roller bearing enabling a high speed rotation by relieving a rolling element load applied to a bearing ring when a temperature rises and an increase in a service life by reducing an edge load on cylindrical rollers. <P>SOLUTION: In this cylindrical roller bearing 10, the plurality of cylindrical rollers 13 as rolling elements are circumferentially and rollingly disposed between the raceway surface 11a of an outer ring 11 and the raceway surface 12a of an inner ring 12. A relief groove 14 having a groove width larger than the axial length of the cylindrical rollers 13 is circumferentially formed in the inner peripheral surface of the inner ring 12 at its axial center part. Furthermore, a notch 15 is formed at the axial end face of the inner ring 12 having the relief groove 14. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an improvement in a roller bearing such as a cylindrical roller bearing used in a rotation support portion of a machine tool, an aircraft, a gas turbine, or the like.

  Conventionally, a cylindrical roller bearing used for a rotation support part of a machine tool or the like is often used up to a negative radial clearance, since importance is attached to rigidity. However, since the temperature of the inner ring is higher than that of the outer ring due to the temperature rise during use of the bearing, the negative radial clearance increases due to thermal expansion and the rolling element load applied to the raceway increases, resulting in accelerated heat generation. There has been a risk of causing seizure during high-speed rotation.

In order to cope with such a problem, conventionally, cylindrical roller bearings shown in FIGS. 9 and 10 have been proposed (see, for example, Patent Document 1).
In this cylindrical roller bearing, a plurality of cylindrical rollers 3 as rolling elements are disposed between a raceway surface 1a of an outer ring 1 and a raceway surface 2a of an inner ring 2 so as to be able to roll in the circumferential direction. 2 in the axial direction intermediate portion of the circumferential surface separated from the raceway surface 1a (or 2a) of at least one of the raceways, that is, in the case of FIG. In the case of 10, the relief groove 4 having a groove width equal to or larger than the axial length of the cylindrical roller 3 is provided in the circumferential direction in the axially intermediate portion of the outer circumferential surface of the outer ring 1.

Thus, by providing the clearance groove 4 having a groove width equal to or greater than the axial length of the cylindrical roller 3 in the axial direction intermediate portion of the outer peripheral surface of the outer ring 1 or the inner peripheral surface of the inner ring 2, The outer ring 1 or the inner ring 2 provided with the relief groove 4 is easily deformed in the radial direction, and the thermal expansion of the race ring provided with the relief groove is reduced against the increase of the negative radial clearance due to the temperature rise of the bearing. The rolling element load applied to the raceway is relaxed, thereby suppressing heat generation and enabling high-speed rotation of the bearing.
Japanese Patent Laid-Open No. 2000-2248

However, in the cylindrical roller bearing described in Patent Document 1, since the rigidity of the outer ring 1 or the inner ring 2 provided with the relief groove 4 is high on both ends in the axial direction of the escape groove 4, the outer ring 1 or the inner ring is formed at this portion. 2 is not easily deformed in the radial direction, and an edge load is likely to be generated on both ends in the axial direction in the axial stress distribution of the cylindrical roller 3, which may cause a decrease in bearing life.
The present invention has been made to eliminate such inconveniences, and can reduce the load on the rolling elements applied to the raceway when the temperature rises to enable high-speed rotation and reduce the edge load of the rollers. An object of the present invention is to provide a roller bearing capable of improving the bearing life.

In order to achieve the above object, the invention according to claim 1 is a roller bearing in which a plurality of rollers as rolling elements are arranged so as to be able to roll in the circumferential direction between the raceway surfaces of a pair of raceways. ,
A clearance groove having a groove width equal to or greater than the axial length of the roller is provided along the circumferential direction at an axially intermediate portion of the circumferential surface separated from the raceway surface of at least one of the pair of raceways. And the notch was provided in the axial direction end surface of the said bearing ring which provided the said escape groove.
The invention according to claim 2 is characterized in that, in claim 1, a heat conduction medium is enclosed in the escape groove.

  According to the present invention, a clearance groove having a groove width equal to or greater than the axial length of the roller is provided in the circumferential direction at an axially intermediate portion of the circumferential surface separated from the raceway surface of at least one of the pair of raceways. By providing a notch on the axial end surface of the race ring provided with a clearance groove, not only the rigidity of the portion where the clearance groove is provided but also the rigidity of both ends in the axial direction of the clearance groove is low. Therefore, it is possible to make the race ring provided with the relief groove easier to deform in the radial direction.

Thereby, against the increase of the negative radial clearance due to the temperature rise of the bearing, it is possible to reduce the thermal expansion of the bearing ring provided with the relief groove and reduce the rolling element load applied to the bearing ring. Heat generation is suppressed and high speed rotation of the bearing can be achieved.
In addition, by providing a notch on the axial end surface of the raceway with a relief groove, the difference in rigidity between the axial center and end of the raceway surface of the raceway is reduced, and the axial stress of the roller is reduced. The distribution can be made uniform, thereby reducing the edge load of the rollers and improving the bearing life.

  Further, by encapsulating the heat transfer medium in the escape groove, it is possible to prevent heat from being trapped in the escape groove portion that does not contact the fitting surface of the raceway ring. As a result, the temperature of the shaft and thus the temperature of the outer ring or the inner ring can be suppressed, and the temperature difference between the inner and outer rings can be prevented from increasing.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view of a main part for explaining a cylindrical roller bearing which is an example of an embodiment of the present invention, and FIGS. 2 to 4 are diagrams for explaining a cylindrical roller bearing which is another embodiment of the present invention. It is principal part sectional drawing.
A cylindrical roller bearing 10, which is an example of an embodiment of the present invention, includes a plurality of cylindrical rollers 13 as rolling elements between a raceway surface 11 a of an outer ring (track ring) 11 and a raceway surface 12 a of an inner ring (track ring) 12. The outer ring 11 is fitted in the housing 20, and the inner ring 12 is fitted on the rotary shaft 21. In this embodiment, the cage is omitted. However, the cage may be applied, and the type of the cage is not particularly limited.

Here, in this embodiment, a uniform groove width equal to or greater than the axial length of the cylindrical roller 13 is provided at the axially intermediate portion of the inner peripheral surface of the inner ring 12 (the peripheral surface away from the raceway surface 12a of the inner ring 12). A relief groove 14 having a depth is provided along the entire circumference.
In addition, notches (notches) 15 are provided along the entire circumference in the axial direction at both end surfaces of the inner ring 12 provided with the relief grooves 14, and the bottom of the notches 15 has an R shape to avoid stress concentration. Is formed.

  As described above, in this embodiment, the clearance groove 14 having a groove width equal to or greater than the axial length of the cylindrical roller 13 is provided along the entire circumference in the axial direction intermediate portion of the outer peripheral surface of the inner ring 12. Since the notches 15 are provided along the entire circumference in the axial direction at both end faces of the inner ring 12 provided with the grooves 14, not only the rigidity of the portion where the escape grooves 14 are provided, but also the axial direction of the escape grooves 14 The rigidity at both ends can also be lowered, and therefore the inner ring 12 provided with the relief groove 14 can be easily deformed in the radial direction.

Thereby, against the increase of the negative radial clearance due to the temperature rise of the bearing, the thermal expansion of the raceway surface 12a of the inner ring 12 can be reduced, and the rolling element load applied to the inner ring 12 can be relaxed. It is possible to suppress the rotation of the bearing at a high speed.
Further, since the notches 15 are provided on both end surfaces in the axial direction of the inner ring 12 provided with the relief grooves 12, the difference in rigidity between the axial center portion and the end portion of the raceway surface 12a of the inner ring 12 is reduced. As a result, the axial stress distribution of the cylindrical roller 13 is leveled, the edge load of the cylindrical roller 13 is reduced, and the bearing life can be improved.

In addition, this invention is not limited to the said embodiment, In the range which does not deviate from the summary of this invention, it can change suitably.
For example, in each of the above embodiments, the relief groove 14 having a uniform depth having a groove width equal to or greater than the axial length of the cylindrical roller 13 is provided in the axially intermediate portion of the inner peripheral surface of the inner ring 12, and the shaft of the inner ring 12 is provided. The notch 15 is provided on each of both end faces in the direction, but instead of this, as shown in FIG. 2, the axial direction intermediate of the outer peripheral surface of the outer ring 11 (the peripheral surface separated from the raceway surface 11 a of the outer ring 11). The same effect as described above can be obtained by providing a relief groove 14 having a uniform depth having a groove width equal to or greater than the axial length of the cylindrical roller 13 at the portion and providing notches 15 at both axial end surfaces of the outer ring 11. Can be obtained.

Moreover, in the said embodiment, although the escape groove 14 is made into the state as a space part, instead of this, as shown in FIG.3 and FIG.4, the escape groove 14 provided in the internal peripheral surface of the inner ring | wheel 12 and For example, a heat conduction medium 16 in which carbon powder or steel powder is mixed in grease may be enclosed in the escape groove 14 provided on the outer peripheral surface of the outer ring 11.
If it does in this way, it can prevent that the heat | fever accumulates in the escape groove 14 part which does not contact the rotating shaft 21 of the inner ring | wheel 12 or the outer ring | wheel 11, or the fitting surface of the housing 20. FIG.

Thereby, the heat of the rotating shaft 21 is efficiently conducted to the inner ring 12, the cylindrical roller 13, and the outer ring 11 to suppress the temperature increase of the rotating shaft 21 and consequently the temperature increase of the inner ring 12 or the outer ring 11 provided with the escape groove 14. Further, it is possible to prevent the temperature difference between the inner ring 12 and the outer ring 11 from increasing.
In addition, the materials, shapes, dimensions, forms, numbers, locations, etc., of the bearing rings, raceway surfaces, cylindrical rollers, relief grooves, notches, heat conduction media, etc. exemplified in the above embodiments can achieve the present invention. As long as it is arbitrary, it is not limited.

Next, in order to confirm the effect of the present invention, the amount of thermal expansion due to the bearing temperature rise of the raceway surface 12a of the inner ring 12 when an interference is applied between the inner ring 12 of the cylindrical roller bearing and the rotating shaft 21 is calculated. Was analyzed.
This analysis is performed in Conventional Examples 1 to 3 and Invention Examples 1 and 2. Conventional Example 1 is a normal cylindrical roller bearing (notch and no relief groove), Conventional Examples 2 and 3 are both notch 15 and relief groove 14. In the present invention examples 1 and 2, both have a notch 15 and a relief groove 14.

The notches 15 and the relief grooves 14 of the conventional examples 2 and 3 and the inventive examples 1 and 2 are both provided on the inner ring 12 side in the same manner as in FIG. 1, and the depth l of the notches 15 is 1.6 mm. Further, Conventional Example 2 and Conventional Example 3 and Invention Example 1 and Invention Example 2 have different axial widths of the relief groove 14, and Conventional Example 2 and Invention Example 1 have t = 22%, In Invention Example 2, t = 11%.
Here, t is t = (2 L / B) where L is the dimension from the end face of the inner ring 12 to the clearance groove 14 and B is the bearing width with reference to FIG. The ratio of the total width 2L (L: L ₁ , L ₂ ) at both ends excluding the escape groove 14 is shown. Therefore, the smaller the value of t, the longer the axial width dimension of the relief groove 14.

Further, as a cylindrical roller bearing to be analyzed, a bearing model number: N1011 (inner diameter φ55 mm, outer diameter φ90 mm, width 18 mm, outer ring collar, inner ring ribs, roller diameter φ8 mm, roller length 8 mm) is used. Except for the presence or absence of the escape groove 14, all of the conventional examples 1 to 3 and the inventive examples 1 and 2 have the same conditions.
Since the bearing width is 18 mm, Conventional Example 2 and Invention Example 1 are t = 22% to L = 1.98 mm, and Conventional Example 3 and Invention Example 2 are t = 11% to L = 0.99 mm. Since the depth l of the notch 15 is 1.6 mm, in FIG. 8, the conventional example 2 and the invention example 1 satisfy l <L, and the notch 15 and the escape groove 14 do not overlap in the axial direction (L ₂ In the conventional example 3 and the present invention example 2, l> L and the notch 15 and the relief groove 14 overlap in the axial direction (L ₁ ).

  5 to 7 show analysis results of the expansion amount of the inner ring raceway surface. 5 shows the relationship between the expansion amount of the inner ring raceway surface and the interference in Examples 1 and 2 of the present invention and Conventional Examples 1 to 3, and FIG. 6 shows the axis of the inner ring raceway surface in Examples 2 and 3 of the present invention. FIG. 7 shows the relationship between the amount of expansion and the interference between the center portion in the direction and the end portion, and FIG. It shows the relationship between the difference and interference.

First, as apparent from FIG. 5, the prior art examples 2 and 3 and the inventive examples 1 and 2 having the relief groove 14 are more suitable for the inner ring 12 than the conventional example 1 in which the notch 15 and the relief groove 14 are not provided. The amount of expansion of the raceway surface 12a is small.
Further, in the conditions where the axial width dimension of the escape groove 14 is the same, the present invention examples 1 and 2 in which both the escape groove 14 and the notch 15 are provided are more than the conventional examples 2 and 3 in which only the escape groove 14 is provided. The amount of expansion of the raceway surface 12a of the inner ring 12 is small. Furthermore, in both of the conventional examples 2 and 3 and the invention examples 1 and 2, the longer the axial width dimension of the escape groove 14 is, the longer the raceway surface 12a of the inner ring 12 is. It can be seen that the amount of expansion is small.

As apparent from FIGS. 6 and 7, the difference in the amount of expansion between the center portion in the axial direction of the raceway surface 12 a of the inner ring 12 and the end portions in the first and second embodiments of the present invention and the second and third embodiments of the present invention is the relief groove 14. It can be seen that Examples 1 and 2 of the present invention in which both the escape groove 14 and the notch 15 are provided are smaller than those in Examples 2 and 3 in which only the above is provided.
For example, in the calculation examples of Conventional Example 3 and Invention Example 2 where t = 11%, the expansion amount of the raceway surface 12a of the inner ring 12 of Conventional Example 3 at an interference of 10 μm is 5 at the center as shown in FIG. .47 mm, 6.03 mm at the end, and the difference is 0.56 mm (see FIG. 7), whereas the expansion amount of the raceway surface 12a of the inner ring 12 of Example 2 of the present invention is as shown in FIG. 5.26 mm at the center and 4.86 mm at the end, the difference is 0.4 mm (see FIG. 7), which is smaller than that of the conventional example 3.

Further, from FIG. 7, the difference in the inner ring raceway surface expansion amount is smaller in Conventional Example 3 and Invention Example 2 where l> L than in Conventional Example 2 and Invention Example 1 where l <L. Accordingly, in FIG. 8, when the overlap between the notch 15 and the relief groove 14 occurs in the axial direction (L ₁ ), the overlap between the notch 15 and the relief groove 14 does not occur in the axial direction (L ₂ ) The difference in inner ring raceway surface expansion becomes smaller.

  From the above results, the first and second embodiments of the present invention in which both the escape groove 14 and the notch 15 are provided are the axially central portion of the raceway surface 12a of the inner ring 12 than the conventional examples 2 and 3 in which only the escape groove 14 is provided. It was confirmed that the difference in the expansion amount between the inner ring 12 and the end portion of the cylindrical roller 13 can be reduced, the rolling element load applied to the inner ring 12 when the bearing temperature is increased, and the edge load of the cylindrical roller 13 can be reduced.

It is principal part sectional drawing for demonstrating the cylindrical roller bearing which is an example of embodiment of this invention. It is principal part sectional drawing for demonstrating the cylindrical roller bearing which is other embodiment of this invention. It is principal part sectional drawing for demonstrating the cylindrical roller bearing which is other embodiment of this invention. It is principal part sectional drawing for demonstrating the cylindrical roller bearing which is other embodiment of this invention. It is a graph which shows the relationship between the amount of expansion of the inner ring raceway surface and the interference in the example of the present invention and the conventional example. It is a graph which shows the relationship between the amount of expansion | extension of the axial direction center part and edge part of an inner ring | wheel track surface in an example of this invention, and a prior art, and interference. It is a graph which shows the relationship between the expansion amount difference of the axial direction center part and edge part of an inner ring | wheel track surface in an example of this invention, and a prior art example, and interference. It is principal part sectional drawing for demonstrating the type | formula of t = (2L / B). It is principal part sectional drawing for demonstrating the conventional cylindrical roller bearing. It is principal part sectional drawing for demonstrating the other conventional cylindrical roller bearing.

Explanation of symbols

10 Cylindrical roller bearing 11 Outer ring (Raceway ring)
11a Raceway surface 12 Inner ring (Raceway)
12a Raceway surface 13 Cylindrical roller 14 Escape groove 15 Notch 16 Heat conduction medium

Claims (2)

A roller bearing in which a plurality of rollers as rolling elements are disposed between the raceway surfaces of a pair of raceways so as to roll in the circumferential direction,
A clearance groove having a groove width equal to or greater than the axial length of the roller is provided along the circumferential direction at an axially intermediate portion of the circumferential surface separated from the raceway surface of at least one of the pair of raceways. And the roller bearing characterized by providing the notch in the axial direction end surface of the said bearing ring which provided the said escape groove.   The roller bearing according to claim 1, wherein a heat conduction medium is sealed in the escape groove.

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