JP2007270903A - Tapered roller bearing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce a loss of torque due to a flow resistance of lubricating oil in a tapered roller bearing inside which the lubricating oil inflows. <P>SOLUTION: A tapered hole 4a for making the lubricating oil inflow therein is formed at the central portion of a tapered roller 4. By this configuration, the amount of the lubricating oil to be accumulated inside the bearing can be reduced, and the loss of the torque due to the flow resistance of the lubricating oil can be reduced. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a tapered roller bearing in which torque loss due to flow resistance of lubricating oil is reduced.

  The tapered roller bearing is composed of an inner ring having small and large flanges on both sides of the raceway surface of the outer diameter surface, an outer ring having a raceway surface on the inner diameter surface, and a plurality of rows arranged between the raceways of the inner ring and the outer ring. The tapered rollers and a cage that holds and stores these tapered rollers in a pocket. The cage is linked to a small annular portion that is continuous on the small-diameter end surface side of the tapered roller and a large-diameter end surface side of the tapered roller. A base consisting of a large annular part and a plurality of pillars connecting these annular parts, the pocket is a narrow side where the small diameter side of the tapered roller is accommodated, and a wide side is the part which accommodates the large diameter side What was formed in the shape is used.

  A tapered roller bearing that supports a power transmission shaft such as a differential or a transmission of a self-propelled vehicle is used in a state where a lower part is immersed in an oil bath. Therefore, an oil bath lubrication state occurs in which the oil in the oil bath flows into the bearing as the lubricating oil as the shaft rotates. In the tapered roller bearing used for such an application, the lubricating oil flows into the bearing from the small diameter side of the tapered roller by a so-called pump action. Lubricating oil flowing from the outer diameter side of the cage passes along the raceway surface of the outer ring to the larger diameter side of the tapered roller. Lubricating oil flowing from the inner diameter side of the cage passes along the raceway surface of the inner ring to the larger diameter side of the tapered roller.

  Lubricating oil flows around the tapered roller from the roller small diameter side to the large diameter side. The tapered roller shears the flow of the lubricating oil so as to revolve between the raceway surfaces of the inner and outer rings in the circumferential direction. For this reason, stirring resistance due to the viscosity of the lubricating oil is generated.

  It is known that solid grease is fitted in a tapered hole formed in the axial center of a tapered roller for the purpose of improving the lubricity of the tapered roller bearing (see Patent Document 1).

Japanese Patent Laid-Open No. 2004-176771 (FIG. 4)

  A tapered roller bearing has a larger rotational torque than a ball bearing. In particular, the tapered roller bearing has an action of drawing the lubricating oil into the bearing by a so-called pump action, and therefore, when used in the oil bath lubrication state, the ratio of the stirring resistance to the torque becomes large. In recent years, there has been a strong demand for energy saving and low fuel consumption as environmental measures, and for tapered roller bearings, it is desired to reduce the torque.

  Accordingly, an object of the present invention is to reduce torque loss due to flow resistance of lubricating oil in a tapered roller bearing in which lubricating oil flows into the bearing.

  In order to solve the above-described problems, the present invention provides an inner ring having small and large flanges on both sides of a raceway surface of an outer diameter surface, an outer ring having a raceway surface on an inner diameter surface, and the inner ring and the outer ring. In a tapered roller bearing comprising a plurality of tapered rollers arranged between raceway surfaces and a cage that holds and holds these tapered rollers in a pocket, the tapered roller has an axial center from a roller small diameter side to a large diameter side. A taper hole having a diameter gradually increased toward is formed. You may form the step part which expands toward the roller large diameter side in the middle of the said taper hole.

  If a tapered hole that gradually increases in diameter from the small roller diameter side to the large diameter side is formed through the axial center of the tapered roller, a pumping action is generated by the tapered hole itself as the tapered roller revolves. That is, the axis of the taper hole is inclined so that the roller large diameter side is separated outward in the radial direction of the bearing, so that the centrifugal force acting on the lubricating oil in the taper hole causes the large diameter from the roller small diameter end in the taper hole. Lubricating oil flow toward the edge is generated. Centrifugal force is greatly influenced by the lubricating oil on the roller large diameter side, so that the lubricating oil flow is promoted. By this pumping action of the tapered hole, the lubricating oil on the inner diameter side of the cage is sucked into the tapered hole from the roller small diameter side and discharged from the roller large diameter side. As described above, generally, the lubricating oil inside the cage is blocked by the inner ring large cage when it passes along the inner ring raceway surface to the larger diameter side of the tapered roller, and tends to stay in the bearing. The tapered hole of the tapered roller functions as a bypass of the lubricating oil having no such place, reducing the amount of lubricating oil staying in the bearing and reducing the torque loss due to the flow resistance of the lubricating oil.

  Since the present invention can be expected to reduce the torque loss due to the tapered roller hole in this way, it is possible to effectively promote energy saving and low fuel consumption of the transportation equipment in combination with the weight reduction of the tapered roller due to the tapered hole.

  The tapered roller bearing of the present invention has a tapered hole formed in the roller axis that gradually increases in diameter from the small roller diameter side to the large diameter side. A pump action that discharges from the outlet of the taper hole is born. This pump action increases the amount of lubricating oil that passes through the tapered hole of the roller, and the lubricating oil that tends to stay in the bearing by being blocked by the inner ring collar is bypassed via the tapered hole, and the lubricating oil tends to stay. Further, the amount of lubricating oil passing between the rollers inside the cage can be reduced, and the stirring resistance of the lubricating oil when the tapered roller revolves can be reduced. As a result, the torque of the tapered roller bearing can be reduced, and energy saving and fuel consumption reduction of transportation equipment such as automobiles can be promoted.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. As shown in FIG. 1, the tapered roller bearing 1 includes a plurality of tapered rollers 4 held in a cage 5 between the raceways 2 a and 3 a of the inner ring 2 and the outer ring 3. The movement in the axial direction is restricted by the small rod 2b and the large rod 2c provided on both sides of the raceway surface 2a of the inner ring 2.

  As shown in FIG. 2, the tapered roller used in the tapered roller bearing of the present invention has a tapered hole that is gradually expanded in diameter from the roller small diameter side toward the large diameter side in the roller shaft center. By setting the tapered hole 4a to have a larger diameter on the larger diameter side of the roller, the amount of lubricating oil inside the tapered hole 4a where the centrifugal force acts is increased and the pump action is strengthened. The tapered hole may be configured with a uniform inclination over the entire length, but may be partially inclined with a steep slope. For example, as shown in FIG. 4, a stepped portion 4b3 that expands toward the roller large diameter side may be formed in the middle of the tapered hole 4b. One side of the stepped portion 4b3 is a large diameter tapered hole 4b1, and the opposite side is a small diameter tapered hole 4b2. The tapered hole 4b can further increase the amount of lubricating oil in the hole as compared with FIG. It is preferable to form both ends of the tapered hole so as to open on the inner diameter side of the cage. If a part of both ends of the tapered hole enters the cage pocket, the flow of the lubricating oil may be hindered.

  The tapered hole is inclined so that the larger diameter side is away from the center of the bearing, so that the lubricating oil flows in from the small diameter side inlet of the roller and flows out from the large diameter side outlet as the tapered roller revolves. Such a tendency of the lubricating oil to flow is reinforced by a shape in which the inner diameter of the tapered hole expands and changes from the small diameter end toward the large diameter end. Since the inlet and outlet of the tapered hole are opened on the inner diameter side of the cage, the tendency of the lubricating oil from the smaller diameter side to the larger diameter side on the cage inner diameter side is reinforced. The lubricating oil coming out of the tapered hole outlet once flows out of the bearing and then flows again into the small diameter side inlet of the tapered roller.

  FIG. 3 shows an automobile differential using the tapered roller bearing 1 described above. The differential is connected to a propeller shaft (not shown), and a drive pinion 22 inserted through the differential case 21 is engaged with a ring gear 24 attached to the 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. Rotate with. When the tapered roller bearings 1a and 1b rotate in this oil bath immersion state, the lubricating oil flows through the tapered hole 4a of the tapered roller as described above, so that the retention of the lubricating oil inside the bearing is suppressed and the flow resistance of the lubricating oil is reduced. Reduce torque loss due to

The longitudinal cross-sectional view which shows embodiment of a tapered roller bearing. The longitudinal cross-sectional view of a tapered roller. The cross-sectional view which shows the differential which uses the tapered roller bearing of FIG. The longitudinal cross-sectional view of a tapered roller.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1, 1a, 1b Tapered roller bearing 2 Inner ring 2a Raceway surface 2b Small flange 2c Large bowl 3 Outer ring 3a Raceway surface 4 Tapered roller 4b3 Step part 5 Cage 21 Differential case 22 Drive pinion 23 Differential gear case 24 Ring gear 25 Pinion gear 26 Side gear 27a, 27b, 27c Seal member

Claims (2)

  An inner ring provided with small and large ridges on both sides of the raceway surface of the outer diameter surface, an outer ring provided with a raceway surface on the inner diameter surface, a plurality of tapered rollers arranged between the raceways of the inner ring and the outer ring, In a tapered roller bearing comprising a retainer that holds and holds these tapered rollers in a pocket, a tapered hole that gradually increases in diameter from the roller small diameter side toward the large diameter side is formed in the axial center of the tapered roller. Tapered roller bearing characterized by   The tapered roller bearing according to claim 1, wherein a stepped portion is formed in the middle of the tapered hole so as to extend toward the roller large diameter side.

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