JP2007170615A - Rolling bearing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rolling bearing which suppresses rise of pressure on a contact face between a bearing ring and a rolling body and prevents early seizure even if a negative radial inside clearance is caused when the bearing rotates, to thereby extend service life of the bearing. <P>SOLUTION: This rolling bearing is provided with: an inner ring 4 and an outer ring 6 arranged opposingly so as to rotate relatively; and a plurality of rolling bodies (cylindrical roller) 2 assembled in between raceway surfaces (an inner ring raceway surface 4m, an outer ring raceway surface 6m) formed on an outside diameter face 4a of the inner ring and an inside diameter face 6b of the outer ring by facing them mutually, so as to roll freely. When outside diameter of the bearing is D and diameter of the raceway surface of the outer ring is D<SB>E</SB>or inside diameter of the bearing is d and diameter of the raceway surface of the inner ring is d<SB>i</SB>, this rolling bearing satisfies the relation of (D/D<SB>E</SB>)≤1.07 or (d/d<SB>i</SB>)≤1.07. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to applications such as main bearings for jet engines and gas turbine engines, internal gearboxes and external gearboxes for these engines, and high-speed pinion bearings for reduction gears. The present invention relates to a rolling bearing used in a structure having a positive bearing clearance between an outer diameter surface and a housing inner diameter surface.

  In conventional cylindrical roller bearings, in consideration of heat treatment deformation of the bearing ring and securing processing accuracy for the bearing ring, the center diameters of a plurality of rolling elements interposed between the bearing rings (the centers are connected to each other). The diameter of the virtual circle) is positioned at the approximate center between the outer diameter of the bearing (outer ring) and the inner diameter of the bearing (inner ring). In this case, the diameter of each rolling element is set to about 50% to 60% of the bearing cross-sectional width (cross-sectional width in the radial direction).

  In such a cylindrical roller bearing, the clearance inside the bearing (radial inside) is, for example, the amount of expansion and contraction of the bearing ring according to the fitting allowance with the rotating shaft and the housing during rotation of the bearing, the temperature between the bearing ring and the rolling element. Considering the amount of change in the radial internal clearance due to the difference, etc., the residual clearance during rotation of the bearing is set to be a positive clearance (for example, Patent Document 1). In addition, the radial internal clearance during bearing rotation is always set to a positive clearance in consideration of variations in the dimensions of the bearing ring, rotating shaft and housing, as well as variations in temperature (heat generation amount) during bearing rotation. ing. In this case, the radial internal clearance becomes zero or more when the bearing rotates, and there is some variation.

  By the way, if the positive radial internal clearance increases when the bearing rotates, it may cause, for example, vibration, noise, or short life of the bearing due to premature damage, and conversely, if the negative radial internal clearance increases when the bearing rotates, a sudden bearing In some cases, the service life is short-lived, and the contact surface pressure between the rolling element and the raceway increases, leading to early seizure. FIGS. 5 (a) and 5 (b) show the relationship between the calculated life of the bearing and the maximum surface pressure associated with the increase or decrease of the radial internal clearance during rotation of the cylindrical roller bearing with the nominal number N208. Incidentally, a radial load Fr of 300 kgf is applied to the bearing of FIG. 9A, while a radial load Fr of 150 kgf is applied to the bearing of FIG. The maximum surface pressure indicates the contact surface pressure between the inner and outer rings and the rolling elements (rollers), and the calculated life indicates the bearing life calculated according to a predetermined calculation formula.

  As is clear from the relationship between FIGS. 4A and 4B, if the positive radial internal clearance increases during bearing rotation, the maximum surface pressure does not increase that much, but the bearing life (calculated life) decreases. It can be seen that if the negative radial internal clearance increases during bearing rotation, the maximum surface pressure increases, leading to premature seizure, resulting in a sudden decrease in bearing life (calculated life). The relationship between FIGS. 5A and 5B is an example when the outer ring is configured as a rigid body. For example, as shown in FIGS. 5C and 5D, the outer ring is not configured as a rigid body. If the negative radial internal clearance increases during bearing rotation, the maximum surface pressure increases, leading to premature seizure. As a result, the bearing life (calculated life) decreases rapidly.

  As a specific example, in a power generation device using a gas turbine engine or the like, the temperature difference of the raceway ring increases due to heat back that occurs during an emergency stop, and this causes the radial internal clearance to become a negative clearance, which causes the contact surface pressure to increase. It may rise excessively, causing indentations on the races and rolling elements, which may cause peeling damage. In addition, cylindrical roller bearings used at high speeds and light loads, such as jet engine and gas turbine engine main bearings, generally increase the relative slip between the race and rolling elements, causing skid damage. Known. In this case, for example, by making the raceway surface of the outer ring into an elliptical shape or a triangular shape, a device for applying a preload to the rolling elements to prevent slipping is applied, but this makes the manufacturing process of the bearing complicated, As a result, the manufacturing cost of the bearing increases.

Here, as a measure against skidding damage, if the radial internal clearance during rotation of the bearing is set to zero or less (negative clearance), the damage can be suppressed. However, the negative radial clearance increases when maintaining the machining accuracy with the bearing and the rotating shaft, or when the temperature difference between the bearing rings during rotation of the bearing increases. Considering the possibility that the contact surface pressure increases and premature seizure of the bearing may occur, it is difficult to set the radial internal clearance to zero or less (negative clearance).
Japanese Utility Model Publication No. 5-86027

  The present invention has been made to solve such a problem, and its purpose is to suppress an increase in contact surface pressure between the raceway and the rolling element even when a negative radial internal clearance occurs during bearing rotation. Another object of the present invention is to provide a rolling bearing capable of preventing the early seizure and extending the life of the bearing.

In order to achieve such an object, the present invention is provided between an inner ring and an outer ring, which are opposed to each other so as to be relatively rotatable, and a raceway surface formed to face the outer diameter surface of the inner ring and the inner diameter surface of the outer ring. (D / D _E ) ≦ 1.07, where D is a rolling bearing having a plurality of rolling elements that are movably incorporated, and D is the outer diameter of the bearing and _DE is the diameter of the raceway surface of the outer ring. Satisfy the relationship.
Further, the present invention provides a plurality of rolls incorporated between an inner ring and an outer ring, which are opposed to each other so as to be relatively rotatable, and raceway surfaces formed to face the outer diameter surface of the inner ring and the inner diameter surface of the outer ring. A rolling bearing provided with rolling elements satisfies the relationship (d / d _i ) ≦ 1.07, where d is the inner diameter of the bearing and d _i is the diameter of the raceway surface of the inner ring.
In such an invention, the inner ring and the outer ring are made of bearing steel and are configured to be elastically deformable. Moreover, cylindrical rollers are applied as rolling elements.

  According to the present invention, even when a negative radial internal clearance is generated during rotation of the bearing, an increase in contact surface pressure between the race and the rolling element is suppressed, and early seizure is prevented, thereby extending the life of the bearing. A rolling bearing that can be realized can be realized.

Hereinafter, a rolling bearing according to an embodiment of the present invention will be described with reference to the accompanying drawings.
FIG. 1A shows a configuration example of a rolling bearing (cylindrical roller bearing) to which a cylindrical roller is applied as the rolling element 2, and the cylindrical roller bearing has an inner ring 4 disposed so as to be relatively rotatable. And an outer ring 6. In this case, the inner ring 4 is externally fitted and fixed to the outer diameter surface 8 s of the rotary shaft 8, and the outer ring 6 is disposed to face the inner diameter surface 10 s of the housing 10, and the outer diameter surface 6 a of the outer ring 6 and the inner diameter surface 10 s of the housing 10. A predetermined (positive) gap W1 is formed between the two. The size of the clearance W1 is arbitrarily set according to the size and shape of an inclusion such as an oil squeeze damper interposed between the outer diameter surface 6a of the outer ring 6 and the inner diameter surface 10s of the housing 10, for example. Therefore, there is no particular limitation here.

  Further, the outer raceway surface 4a of the inner ring 4 and the inner raceway surface 6b of the outer ring 6 are formed with facing raceways (inner raceway surface 4m, outer raceway surface 6m) facing each other in the circumferential direction. A plurality of rolling elements (cylindrical rollers) 2 are incorporated between these raceway surfaces 4m and 6m so as to be freely rollable. Further, a cage 12 is interposed between the inner and outer rings 4 and 6, and a plurality of rolling elements (cylindrical rollers) 2 are rotatably held by the cage 12 one by one. The cage 12 is not particularly limited because any type of cage can be applied as long as the rolling element (cylindrical roller) 2 can be rotatably held. Moreover, about the material of the said holder | retainer 12, since resin, a metal, etc. are applicable, for example, it does not specifically limit here.

In the present embodiment, the cylindrical roller bearing as described above has a bearing outer diameter dimension (diameter dimension of the outer diameter surface 6a of the outer ring 6) as D and a diameter dimension of the raceway surface 6m of the outer ring 6 as D _E ( D / D _E ) ≦ 1.07 is satisfied. That is, the outer ring 6 is configured to have a smaller cross-sectional width (a radial cross-sectional width). In this case, high-carbon chromium bearing steel, heat-resistant bearing steel, heat-resistant carburized bearing steel, etc. are used as the material of the rolling elements (cylindrical rollers) 2 and the inner and outer rings 4, 6, even when such bearing steel is applied. The outer ring 6 can be configured to be elastically deformable by reducing the cross-sectional width of the outer ring 6.

  According to such a configuration, if the clearance inside the bearing (radial interior) becomes a negative clearance while the inner and outer rings 4 and 6 are rotating relative to each other due to the rotation of the rotating shaft 8, the outer ring 6 is turned into a rolling element ( By receiving the load from the cylindrical roller) 2 and elastically deforming in the direction of the inner surface 10s of the housing 10, the preload (rolling element load) generated in the bearing can be reduced. Thereby, an increase in contact surface pressure between the rolling elements (cylindrical rollers) 2 and the inner and outer rings 4, 6 (track surfaces 4m, 6m) can be suppressed. In this case, it is possible to prevent early seizure of the bearing, and as a result, it is possible to extend the life of the bearing.

  Specifically, in a power generation apparatus using a gas turbine engine or the like, when the temperature difference of the raceway ring increases due to the soak back that occurs during an emergency stop, and the radial internal clearance becomes a negative clearance, the outer ring 6 Suppressing an increase in contact surface pressure between the rolling element (cylindrical roller) 2 and the inner and outer rings 4 and 6 (track surface 4m, 6m) by receiving elastic load from the rolling element (cylindrical roller) 2 be able to. As a result, it is possible to prevent the occurrence of indentation and peeling damage to the rolling elements (cylindrical rollers) 2 and the inner and outer rings 4 and 6 (the raceway surfaces 4 m and 6 m). It can continue to operate stably.

  Further, in a cylindrical roller bearing used at high speed and light load, such as a main bearing of a jet engine or a gas turbine engine, when the radial internal clearance becomes a negative clearance, the outer ring 6 starts from the rolling element (cylindrical roller) 2. It is possible to suppress an increase in contact surface pressure between the rolling element (cylindrical roller) 2 and the inner and outer rings 4 and 6 (the raceway surfaces 4m and 6m). As a result, it is possible to prevent the occurrence of skid damage and to prevent early seizure of the bearing. As a result, it is possible to extend the life of the bearing.

  FIG. 1B shows a configuration example of a rolling bearing according to another embodiment of the present invention. Cylindrical rollers are also applied as rolling elements 2 to the rolling bearings of this configuration example, and have the same configuration as that of the above-described embodiment (FIG. 1 (a)). The difference is that the outer ring 6 is fitted and fixed to the inner diameter surface 10 s of the housing 10, and the inner ring 4 is disposed opposite to the outer diameter surface 8 s of the rotating shaft 8. A predetermined (positive) gap W2 is formed between the radial surface 8s. The size of the clearance W2 is arbitrarily set according to the size and shape of an inclusion such as an oil squeeze damper interposed between the inner diameter surface 4b of the inner ring 4 and the outer diameter surface 8s of the rotating shaft 8, for example. Therefore, there is no particular limitation here.

Cylindrical roller bearing in the configuration example of FIG. 1 (b), the bearing inner diameter d, the diameter of the raceway surface 4m of the inner ring 4 and d _i, satisfying the (d / d _i) ≦ 1.07 the relationship It is configured as follows. That is, the inner ring 4 is configured to have a smaller cross-sectional width (a radial cross-sectional width). In this case, high-carbon chromium bearing steel, heat-resistant bearing steel, heat-resistant carburized bearing steel, etc. are used as the material of the rolling elements (cylindrical rollers) 2 and the inner and outer rings 4, 6, even when such bearing steel is applied. The inner ring 4 can be configured to be elastically deformable by reducing the cross-sectional width of the inner ring 4.

  According to such a configuration, if the clearance inside the bearing (radial interior) becomes a negative clearance while the inner and outer rings 4 and 6 are rotating relative to each other due to the rotation of the rotating shaft 8, the inner ring 4 is a rolling element ( By receiving a load from the cylindrical roller) 2 and elastically deforming in the direction of the outer diameter surface 8s of the rotary shaft 8, the preload (rolling element load) generated inside the bearing can be reduced. Thereby, an increase in contact surface pressure between the rolling elements (cylindrical rollers) 2 and the inner and outer rings 4, 6 (track surfaces 4m, 6m) can be suppressed. In this case, early seizure of the bearing can be prevented, and as a result, the life of the bearing can be extended. Since other effects are the same as those of the above-described embodiment (FIG. 1A), description thereof is omitted.

Here, the effects as described above will be verified with reference to the relationship between the bearing life (calculated life) and the maximum surface pressure when the radial internal clearance becomes negative (FIGS. 2 to 4).
The rolling bearings (cylindrical roller bearings) shown in FIGS. 1 (a) and 1 (b) have the same effects. Therefore, the effects of the cylindrical roller bearings illustrated in FIG. 1 (a) will be described below. Validate. That is, in the cylindrical roller bearing, assuming that the outer diameter of the bearing (the diameter of the outer diameter surface 6a of the outer ring 6) is D and the diameter of the raceway surface 6m of the outer ring 6 is D _E , (D / D _E ) ≦ 1 0.07 is satisfied.

2 (a) and 2 (b) show the relationship between the bearing life (calculated life) and the maximum surface pressure when a negative (−0.010) radial internal clearance is applied to a cylindrical roller bearing with the nominal number N208. Has been. A radial load Fr of 300 kgf is applied to the bearing shown in FIG. 5A, while a radial load Fr of 150 kgf is applied to the bearing shown in FIG. As is apparent from the relationship between FIGS. 4A and 4B, the rolling element (cylindrical roller) 2 and the inner and outer surfaces are formed by configuring the bearing so as to satisfy the relationship of (D / D _E ) ≦ 1.07. It was verified that the bearing life can be extended by suppressing the increase in contact surface pressure between the rings 4 and 6 (the raceway surfaces 4m and 6m).

3 (a) and 3 (b) show the relationship between the bearing life (calculated life) and the maximum surface pressure when a negative (−0.020) radial internal clearance is obtained in a cylindrical roller bearing with the nominal number N208. Has been. A radial load Fr of 300 kgf is applied to the bearing shown in FIG. 5A, while a radial load Fr of 150 kgf is applied to the bearing shown in FIG. As is apparent from the relationship between FIGS. 4A and 4B, the rolling element (cylindrical roller) 2 and the inner and outer surfaces are formed by configuring the bearing so as to satisfy the relationship of (D / D _E ) ≦ 1.07. It was verified that the bearing life can be extended by suppressing the increase in contact surface pressure between the rings 4 and 6 (the raceway surfaces 4m and 6m).

4 (a) and 4 (b) show the relationship between the bearing life (calculated life) and the maximum surface pressure when a negative (−0.050) radial internal clearance is applied to the cylindrical roller bearing with nominal number N208. Has been. A radial load Fr of 300 kgf is applied to the bearing shown in FIG. 5A, while a radial load Fr of 150 kgf is applied to the bearing shown in FIG. As is apparent from the relationship between FIGS. 4A and 4B, the rolling element (cylindrical roller) 2 and the inner and outer surfaces are formed by configuring the bearing so as to satisfy the relationship of (D / D _E ) ≦ 1.07. It was verified that the bearing life can be extended by suppressing the increase in contact surface pressure between the rings 4 and 6 (the raceway surfaces 4m and 6m).

  In the above-described embodiment, the description has been made on the assumption that a rolling bearing using a cylindrical roller is used as the rolling element 2, but for example, a rolling bearing using a tapered roller, a needle roller, a spherical roller, or the rolling element 2 is used. The technical idea of the present invention can also be applied to a rolling bearing to which balls are applied.

(a) is sectional drawing which shows the structure of the rolling bearing which concerns on one embodiment of this invention, (b) is sectional drawing which shows the structure of the rolling bearing which concerns on other embodiment of this invention. (a) is a diagram showing the relationship between the bearing life (calculated life) and the maximum surface pressure when a negative (−0.010) radial internal clearance is obtained in a bearing loaded with a radial load Fr of 300 kgf, (b) ) Is a diagram showing the relationship between the bearing life (calculated life) and the maximum surface pressure when a negative (−0.010) radial internal clearance is obtained in a bearing loaded with a radial load Fr of 150 kgf. (a) is a diagram showing the relationship between the bearing life (calculated life) and the maximum surface pressure when a negative (−0.020) radial internal clearance is obtained in a bearing loaded with a radial load Fr of 300 kgf, (b) ) Is a diagram showing the relationship between the bearing life (calculated life) and the maximum surface pressure when a negative (−0.020) radial internal clearance is obtained in a bearing loaded with a radial load Fr of 150 kgf. (a) is a diagram showing the relationship between the bearing life (calculated life) and the maximum surface pressure when a negative (−0.050) radial internal clearance is obtained in a bearing loaded with a 300 kgf radial load Fr. ) Is a diagram showing the relationship between the bearing life (calculated life) and the maximum surface pressure when a negative (−0.050) radial internal clearance is obtained in a bearing loaded with a radial load Fr of 150 kgf. In a conventional bearing, it is a figure which shows the relationship between the calculation life of a bearing accompanying the increase / decrease in the radial internal clearance at the time of bearing rotation, and the maximum surface pressure, (a) And (b) is the case where an outer ring | wheel is comprised as a rigid body. The figure which shows an example, (c) And (d) is a figure which shows an example when not comprising an outer ring | wheel as a rigid body.

Explanation of symbols

2 Rolling element 4 Inner ring 4a Inner ring outer diameter surface 4b Inner ring inner diameter surface 4m Inner ring raceway surface 6 Outer ring 6a Outer ring outer diameter surface 6b Outer ring inner diameter surface 6m Outer ring raceway surface

Claims (5)

An inner ring and an outer ring that are arranged to face each other so as to be relatively rotatable, and a plurality of rolling elements that are rotatably incorporated between raceway surfaces formed to face the outer diameter surface of the inner ring and the inner diameter surface of the outer ring, respectively. A rolling bearing,
When the outer diameter of the bearing is D and the diameter of the raceway surface of the outer ring is _DE , (D / D _E ) ≦ 1.07
A rolling bearing characterized by satisfying the following relationship. An inner ring and an outer ring that are arranged to face each other so as to be relatively rotatable, and a plurality of rolling elements that are rotatably incorporated between raceway surfaces formed to face the outer diameter surface of the inner ring and the inner diameter surface of the outer ring, respectively. A rolling bearing,
Bearing inner diameter d, the diameter of the inner ring raceway surface and _{d i, (d / d i} ) ≦ 1.07
A rolling bearing characterized by satisfying the following relationship.   The rolling bearing according to claim 1, wherein the outer ring is formed of bearing steel and is configured to be elastically deformable.   The rolling bearing according to claim 2, wherein the inner ring is made of bearing steel and is configured to be elastically deformable. The rolling bearing according to claim 1, wherein a cylindrical roller is applied as the rolling element.

Images