JP2008002661A - Roller bearing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent seizure between the tapered face of a columnar portion and the outer diameter face of a roller while reducing torque loss resulting from lubricating oil entering into a wedge space between the tapered face of the columnar portion and the outer diameter face of the roller. <P>SOLUTION: A length size L in the cross direction of the tapered face 8a of the columnar portion 8 of a cage 5 with which the outer diameter face of the tapered roller 4 has slide contact is less than 11% of an average diameter D of the tapered roller 4. The tapered face 8a is covered with a manganese phosphate salt film 10 to avoid the formation of the so-large wedge space between the outer diameter face of the tapered roller 4 and the tapered face 8a. Thus, prevented is seizure between the tapered face 8a of the columnar portion 8 and the outer diameter face of the tapered roller 4 while reducing torque loss resulting from lubricating oil entering into the wedge space. <P>COPYRIGHT: (C)2008,JPO&amp;INPIT

Description

  The present invention relates to a roller bearing suitable for use in a region where lubricating oil flows from the outside.

  The roller bearings such as the cylindrical roller bearing and the tapered roller bearing are composed of an inner ring having a raceway surface on the outer diameter surface, an outer ring having a raceway surface on the inner diameter surface, and a plurality of rollers arranged between the raceways of the inner ring and the outer ring. And a cage for holding these rollers, and the cage has a pocket for accommodating the roller by an annular portion continuous at both ends of the roller and a plurality of column portions connecting these annular portions. What was formed is used. In such a cage, tapered surfaces are provided on both sides of the inner diameter surface of each column portion in which the outer diameter surface of the roller is in sliding contact so that no contact wrinkles occur on the outer diameter surface of the roller. Conventionally, the length dimension L in the width direction of the tapered surface is 11 to 20% of the average diameter D of the rollers.

  Roller bearings that support power transmission shafts such as differentials and transmissions of self-propelled vehicles are used in a state where some are immersed in an oil bath, and the oil in the oil bath that flows into the bearing as it rotates rotates with the lubricating oil. The oil bath lubrication state. In such a roller bearing used in an oil bath lubricated state, the lubricating oil that enters the wedge space formed by these surfaces is also formed between the outer diameter surface of the roller and the tapered surface of the inner diameter surface of the column portion of the cage. Lubricated.

  In the conventional roller bearing in which the length dimension L in the width direction of the tapered surface of the columnar portion of the cage described above is 11 to 20% of the average diameter D of the roller, the outer diameter surface of the roller, the columnar tapered surface, A relatively large wedge space is formed between them, and a large amount of lubricating oil enters the wedge space. Since the amount of lubricating oil entering the interface between the outer diameter surface of the roller and the tapered surface of the cage is limited from this wedge space, if a large amount of lubricating oil enters the wedge space in this way, these lubricating oils There is a problem that there is no escape space and there is resistance to rotation of the bearing, and torque loss increases.

  In order to solve such a problem, the present applicant sets the length L in the width direction of the tapered surface of the column part to be 5% or more and less than 11% of the average diameter D of the roller, We have proposed to reduce the torque loss due to the fact that the amount of lubricating oil entering the wedge space is reduced so that the wedge space does not escape, so that a very large wedge space is not formed between the tapered surface and the tapered surface. (Japanese Patent Application No. 2005-206703).

  Thus, when the length L in the width direction of the tapered surface of the column portion is reduced and the amount of lubricating oil entering the wedge space formed between the outer diameter surfaces of the rollers is reduced, the column portions that are in sliding contact with each other. There is a possibility that seizure may occur between the outer diameter surface of the taper surface.

  Accordingly, an object of the present invention is to reduce torque loss caused by lubricating oil entering the wedge space between the tapered surface of the column portion and the outer diameter surface of the column portion. It is to prevent seizure between.

  In order to solve the above problems, the present invention is arranged between an inner ring having a raceway surface on an outer diameter surface, an outer ring having a raceway surface on an inner diameter surface, and between the raceways of the inner ring and the outer ring. It consists of a plurality of rollers and a cage that holds these rollers in a pocket, and the cage consists of an annular portion that is continuous at both ends of the roller, and a plurality of column portions that connect these annular portions, In the roller bearing provided with tapered surfaces on both sides of the inner diameter surfaces of the column portions, the outer diameter surfaces of the rollers are in sliding contact, the length dimension in the width direction of the tapered surfaces of the column portions is set to the average diameter of the rollers. 5% or more and less than 11%, and a configuration was adopted in which at least the columnar portion of the cage was covered with a phosphate treatment film.

  That is, by setting the length dimension in the width direction of the taper surface of the column portion of the cage that the outer diameter surface of the roller is in sliding contact to be less than 11%, preferably 9% or less of the average diameter of the roller, the outer diameter of the roller A large wedge space is not formed between the surface and the tapered surface to reduce the amount of lubricating oil entering the wedge space, reducing torque loss due to the lubricating oil entering the wedge space, and the cage. By covering at least the tapered surface of the column with a phosphate treatment film, seizure between the tapered surface and the outer diameter surface of the column can be prevented.

  The length dimension in the width direction of the tapered surface is set to 5% or more of the average diameter of the rollers. If the length is less than 5%, the elastic contact region between the outer diameter surface of the roller and the tapered surface is larger than the width of the tapered surface. Because there is a risk of becoming larger. In addition, as the phosphate-treated film, a zinc phosphate-based film, a manganese phosphate-based film, an iron phosphate-based film, etc. can be adopted, but the initial conformability, lubricity, and wear resistance on the sliding surface. In view of the above, a manganese phosphate coating is preferred.

  By making the thickness of the column part 5% or more and less than 17% of the average diameter of the roller, the thickness of the column part is reduced and the flow resistance of the lubricating oil against the rotation of the cage is reduced. Torque loss can be further reduced. The reason why the thickness of the column portion is set to 5% or more of the average diameter of the rollers is that if the thickness is less than 5%, sufficient rigidity of the cage cannot be secured.

  The roller bearing is suitable for a tapered roller bearing in which the roller is a tapered roller.

  Each roller bearing mentioned above is suitable for what supports the power transmission shaft of a self-propelled vehicle.

  In the roller bearing of the present invention, the length dimension in the width direction of the tapered surface of the column portion of the cage in which the outer diameter surface of the roller is in sliding contact is 5% or more of the average diameter of the roller and less than 11%, preferably 9%. Since the taper surface of at least the pillar portion of the cage is coated with a phosphate treatment film, torque loss due to lubricating oil entering the wedge space between the outer diameter surface of the roller and the taper surface can be reduced. Further, seizure between the tapered surface and the outer diameter surface of the column portion can be prevented.

  By making the thickness dimension of the column part 5% or more of the average diameter of the rollers and less than 17%, the thickness of the column part is reduced, and the flow resistance of the lubricating oil against the rotation of the cage is reduced, Torque loss can be further reduced.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. As shown in FIG. 1, the roller bearing 1 is a tapered roller bearing in which a plurality of tapered rollers 4 are held by a cage 5 between the raceways 2 a and 3 a of an inner ring 2 and an outer ring 3.

  As shown in FIG. 2A, the retainer 5 includes annular portions 6 and 7 that are continuous at both ends of the tapered roller 4, and a plurality of column portions 8 that connect the annular portions 6 and 7. A trapezoidal pocket 9 is formed. As shown in FIG. 2B, tapered surfaces 8a with which the outer diameter surface of the tapered roller 4 is slidably contacted are provided on both sides of the inner diameter surface of the column portion 8, and the length dimension L in the width direction of the tapered surface 8a is provided. Is 7% of the average diameter D of the tapered rollers 4. Therefore, a very large wedge space is not formed between the outer diameter surface of the tapered roller 4 and the tapered surface 8a. Further, the thickness T of the column portion 8 is formed to be as thin as 10% of the average diameter D of the tapered rollers 4 so that the flow resistance of the lubricating oil against the rotation of the cage 5 can be reduced. Further, the entire surface of the cage 5 including the tapered surface 8a of the column part 8 is covered with a manganese phosphate salt film 10 as a phosphate treatment film, and the tapered roller 4 and the tapered surface 8a of the column part 8 The occurrence of seizure due to sliding contact can be prevented.

  FIG. 3 shows an automobile differential using the tapered roller bearing 1 described above. In this differential, a drive pinion 22 inserted through a differential case 21 connected to a propeller shaft (not shown) is engaged with a ring gear 24 attached to a differential gear case 23 and attached to the inside of the differential gear case 23. The pinion gear 25 thus engaged is engaged with a side gear 26 connected to a drive shaft (not shown) inserted through the differential gear case 23 from the left and right, and the driving force of the engine is transmitted from the propeller shaft to the left and right drive shafts. It is like that. In this differential, a drive pinion 22 that is a power transmission shaft and a differential gear case 23 are supported by a pair of tapered roller bearings 1a and 1b, respectively.

  Lubricating oil is stored in the differential case 21 and sealed with seal members 27a, 27b, and 27c, and the tapered roller bearings 1a and 1b are immersed in the oil bath of the stored lubricating oil. And the oil in the oil bath flows into the bearing.

  A tapered roller bearing (Example) using a cage shown in FIGS. 2 (a) and 2 (b) using a cage in which the length L in the width direction of the tapered surface is 7% of the average diameter D of the tapered roller; A tapered roller bearing (comparative example) using a conventional cage in which the length dimension L in the width direction of the surface was 13% of the average diameter D of the tapered roller was prepared. Each tapered roller bearing had dimensions of an outer diameter of 100 mm, an inner diameter of 45 mm, and a width of 27.25 mm. Further, the thickness T of the column portion of the cage was set to 13% of the average diameter D of the tapered roller in the example and 17% in the comparative example.

About the tapered roller bearing of the said Example and the comparative example, the torque measurement test using the vertical torque tester was done. The test conditions are as follows.
・ Axial load: 300kgf
・ Rotation speed: 300-2000 rpm (100 rpm pitch)
・ Lubrication conditions: Oil bath lubrication (lubricating oil: 75W-90)

  FIG. 4 shows the results of the torque measurement test. The vertical axis of the graph of FIG. 4 represents the torque reduction rate of the embodiment with respect to the torque of the comparative example. In the example in which the length dimension L in the width direction of the tapered surface is reduced to 7% of the average diameter D of the tapered roller, a remarkable torque reduction effect is recognized from low speed rotation to high speed rotation. Even at a certain 2000 rpm, a torque reduction rate of 12.0% is obtained. The torque reduction effect of this embodiment includes the effect of reducing the flow resistance of the lubricating oil against the rotation of the cage by reducing the thickness dimension T of the column portion.

  In the embodiment described above, the phosphate treatment film is a manganese phosphate salt film, and the entire surface of the cage is coated. However, the phosphate treatment film may be another film such as a zinc phosphate-based film. You may coat | cover only the taper surface of a pillar part with this film | membrane. The roller bearing according to the present invention is not limited to a tapered roller bearing, and can be applied to other roller bearings such as a cylindrical roller bearing.

Longitudinal sectional view showing an embodiment of a roller bearing a is a developed plan view of the cage of FIG. 1, and b is a cross-sectional view taken along line IIb-IIb of a. Cross-sectional view showing a differential using the tapered roller bearing of FIG. Graph showing results of torque measurement test

Explanation of symbols

DESCRIPTION OF SYMBOLS 1, 1a, 1b Tapered roller bearing 2 Inner ring 3 Outer ring 2a, 3a Raceway surface 4 Tapered roller 5 Cage 6, 7 Annular part 8 Column part 8a Tapered surface 9 Pocket 10 Manganese phosphate film 21 Differential case 22 Drive pinion 23 Difference Dynamic gear case 24 Ring gear 25 Pinion gear 26 Side gear 27a, 27b, 27c Seal member

Claims (4)

  An inner ring having a raceway surface on an outer diameter surface, an outer ring having a raceway surface on an inner diameter surface, a plurality of rollers arranged between the raceways of the inner ring and the outer ring, and holding these rollers in a pocket A cage, and the cage comprises an annular portion that is continuous at both ends of the roller, and a plurality of column portions that connect the annular portions, and the rollers are arranged on both sides of the inner diameter surface of these column portions. In the roller bearing provided with the tapered surface with which the outer diameter surface is slidably contacted, the length in the width direction of the tapered surface of the column portion is 5% or more and less than 11% of the average diameter of the roller, and the cage A roller bearing characterized in that at least the tapered surface of the column part is coated with a phosphate treatment film.   The roller bearing according to claim 1, wherein a thickness dimension of the column portion is 5% or more and less than 17% of an average diameter of the rollers.   The roller bearing according to claim 1, wherein the roller bearing is a tapered roller bearing in which the roller is a tapered roller.   The roller bearing according to any one of claims 1 to 3, wherein the roller bearing supports a power transmission shaft of a self-propelled vehicle.

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