JP2007285357A - Tapered roller bearing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce torque loss due to the presence of a lubricating oil in a tapered roller bearing into which the lubricating oil flows. <P>SOLUTION: A through-hole for flowing the lubricating oil is formed through the axis of the tapered roller bearing 4. The lateral length L of the tapered surface 8a of the column part 8 of a cage 5 in slidable contact with the outer diameter surface of tapered rollers 4 is less than 11% of the averaged diameter D of the rollers. Since the amount of the lubricating oil remaining in the bearing is reduced, a torque loss due to the flow resistance of the lubricating oil is 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 includes 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 tapered rollers arranged between the raceways of the inner ring and the outer ring, and these tapered rollers. The cage is formed by forming a pocket for storing the tapered roller by an annular portion that is continuous at both ends of the tapered roller and a plurality of column portions that connect these annular portions. It has been. 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.

  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.

  Also, in roller bearings used in oil bath lubrication, lubrication is performed between the outer diameter surface of the roller and the tapered surface of the inner diameter surface of the cage column with lubricating oil that enters the wedge space formed by these surfaces. Is done.

  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.

  Further, in the conventional roller bearing in which the length dimension L of the columnar tapered surface of the cage is 11 to 20% of the average diameter D of the roller, the comparison is made between the outer diameter surface of the roller and the columnar tapered surface. A large wedge space is formed, 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, the escape place of these lubricating oils There is a problem that the torque loss is increased due to the bearing rotation resistance. Thus, in the roller bearing in which the lubricating oil flows into the bearing, the flow resistance of the lubricating oil with respect to the rotation of the cage also causes a torque loss that cannot be ignored.

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

  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. A plurality of tapered rollers; and a retainer for holding these tapered rollers in pockets, the retainer being connected to both ends of the tapered rollers, and a plurality of column portions connecting these annular portions. In the roller bearing provided with tapered surfaces on both sides of the inner diameter surfaces of these column portions, the outer diameter surfaces of the tapered rollers are in sliding contact, a through hole is formed in the axial center of the tapered roller, and the column portions The length dimension of the taper surface in the width direction was 5% or more of the average diameter of the roller and less than 11%.

  If a through-hole is formed in the axial center of a tapered roller, the pump action by a through-hole itself will arise with the revolution of a tapered roller. That is, the axis of the through-hole is inclined so that the roller large-diameter side is separated outward in the radial direction of the bearing. Therefore, the centrifugal force acting on the lubricating oil in the through-hole causes the large diameter from the roller small-diameter end in the through-hole. A lubricating oil flow toward the radial end is generated. By this pump action, the lubricating oil on the inner diameter side of the cage is sucked into the through hole from the small diameter side of the roller and discharged from the large diameter side of the roller. 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 through hole of the tapered roller functions as a bypass of the lubricating oil having no such place, reducing the amount of the lubricating oil staying in the bearing and reducing the torque loss due to the flow resistance of the lubricating oil.

  Further, by setting the length dimension in the width direction of the taper surface of the column portion of the cage in which the outer diameter surface of the roller is in sliding contact to be less than 11% of the average diameter of the roller, preferably 9% or less, the outer diameter of the roller By avoiding the formation of a very large wedge space between the surface and the tapered surface, the amount of lubricating oil entering the wedge space can be reduced, and torque loss due to the absence of the escape space for the lubricating oil can be reduced. The length of the taper surface in the width direction is set to 5% or more of the average diameter of the roller. When the length is less than 5%, the elastic contact region between the outer surface of the roller and the taper surface is larger than the width of the taper surface. This is because there is a risk of becoming larger.

  Since the present invention can be expected to reduce the torque loss by both the roller through hole and the dimension setting in the width direction of the taper surface of the cage column, it is possible to reduce the energy consumption of the transportation equipment in combination with the weight reduction of the tapered roller by the through hole. Effectively promote fuel efficiency.

  The through hole is a tapered hole that gradually increases in diameter from the roller small-diameter end side toward the large-diameter end side, or a small-diameter hole on the roller small-diameter end side and a large-diameter hole on the large-diameter end side. Can be configured. It is also possible to form a step portion in the middle of these through holes as required. By forming a spiral groove on the inner peripheral surface of the through hole, the pumping action of the through hole can be further enhanced with the rotation of the tapered roller.

  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.

  Since the roller bearing of the present invention has a through-hole formed in the roller shaft center, a pumping action is produced in which lubricating oil is sucked from the small-diameter side through-hole inlet and discharged from the large-diameter side through-hole outlet. This pumping action increases the amount of lubricating oil that passes through the roller's through hole, and tends to stay in the bearing by bypassing the lubricating oil that was dammed by the inner ring ridge and tends to stay inside the bearing. 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.

  In addition, since the length dimension in the width direction of the tapered surface of the column portion of the cage that the outer diameter surface of the roller slidably contacts is 5% or more of the average diameter of the roller and less than 11%, preferably 9% or less, By avoiding the formation of a very large wedge space between the outer diameter surface of the roller and the tapered surface, the amount of lubricating oil entering the wedge space can be reduced, and torque loss due to the elimination of the lubricating oil can be 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 FIGS. 2 (A) to 2 (E), the tapered roller used in the tapered roller bearing of the present invention has a through hole formed in the roller shaft center. The through-holes may be configured with a uniform diameter over the entire length, but in order to enhance the pumping action of the through-holes, different diameter through-holes having a small diameter on the roller small diameter side and a large diameter on the roller large diameter side as follows It is good to do. As a result, the amount of lubricating oil in the through hole is increased, and the centrifugal force acting on the lubricating oil is increased as the roller revolves. Both ends of the through hole are preferably formed so as to open on the inner diameter side of the cage. If a part of both end openings of the through hole enter the cage pocket, the flow of the lubricating oil may be hindered.

  FIG. 2A shows a through hole formed by a tapered hole 4a that gradually increases in diameter from the roller small diameter side toward the large diameter side. 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.

FIG. 2B shows a through hole formed by a tapered hole 4b whose diameter gradually increases from the roller small diameter end toward the large diameter end. An inclined step 4b ₃ is formed in the middle of the through hole. One side of the inclined step portion 4b ₃ is the large diameter tapered hole 4b ₁ and the other side is the small diameter tapered hole 4b ₂ . Since this through hole can further increase the amount of lubricating oil in the through hole as compared with FIG. 2A, the pumping action of the through hole can be further enhanced.

FIG. 2C shows a through hole formed by a stepped hole 4c. The stepped hole 4c is a through hole in which two types of large and small uniform diameter holes 4c ₁ and 4c ₂ are made continuous from the roller small diameter end to the large diameter end. Uniform diameter hole 4c ₁ Gakoro large diameter side of the large diameter, is formed in the uniform diameter hole 4c ₂ Gakoro small diameter end side of the small diameter. Large and small holes 4c ₁ and 4c ₂ are connected at the center in the roller axial direction, and a radial step 4c ₃ is formed here.

FIG. 2D is a through-hole formed by a stepped hole 4d in which two types of large and small uniform diameter holes 4d ₁ and 4d ₂ are continuous from the small-diameter end to the large-diameter end as in (C). holes _4d 1, 4d ₂ stepped portion 4d ₃ of the portion connected with Gakoro axial center is inclined. That is, a tapered step portion 4d ₃ having a gradually increased diameter from the small diameter hole 4d ₂ to the large diameter hole 4d ₁ is formed.

FIG. 2E shows a through hole formed by a grooved tapered hole 4e that gradually increases in diameter from the roller small diameter end toward the large diameter end. The grooved through-hole 4e is roller toward the small diameter end to the large diameter end is obtained by forming a spiral groove 4e ₂ on the inner peripheral surface of the tapered hole 4e ₁ was gradually diverging. The direction in which the spiral groove 4e ₂ is formed is preferably a direction that promotes the flow of the lubricating oil in the through hole as the tapered roller rotates.

  In any tapered roller, the tapered roller axis is inclined so that the larger diameter side is away from the center of the bearing, so that the lubricating oil flows from the small diameter side inlet of the roller along with the revolution movement of the tapered roller. It flows out from the exit. Such a tendency of the lubricating oil to flow is reinforced by a shape in which the inner diameter of the through hole expands and changes from the small diameter end toward the large diameter end. Since the inlet and outlet of the through 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. Lubricating oil coming out of the through-hole outlet once flows out of the bearing and then flows into the small diameter side inlet of the tapered roller again.

  As shown in FIG. 3A, 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. 3B, on both sides of the inner diameter surface of the column portion 8, tapered surfaces 8a with which the outer diameter surface of the tapered roller 4 comes into sliding contact are provided, and the length dimension L in the width direction of the tapered surface 8a. 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.

  FIG. 4 shows a differential of an automobile 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. 3A and 3B in which the length L of the tapered surface is 7% of the average diameter D of the tapered roller, and the length of the tapered surface. A tapered roller bearing (comparative example) using a conventional cage having a length L of 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. In either case, a tapered hole 4a is formed in a common specification as shown in FIG.

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. 5 shows the results of the torque measurement test. The vertical axis of the graph of FIG. 5 represents the torque reduction rate of the embodiment with respect to the torque of the comparative example. In the example in which the length L 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, and even at the maximum rotation speed of 2000 rpm of the test. 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 roller bearing is a tapered roller bearing, but the roller bearing according to the present invention can also be applied to a cylindrical roller bearing or a barrel roller bearing.

Longitudinal sectional view showing an embodiment of a roller bearing (A)-(E) are longitudinal cross-sectional views of a tapered roller. (A) is a development top view of the cage of Drawing 1, and (B) is a sectional view which met an IIb-IIb line of (A). The cross-sectional view which shows the differential which uses the tapered roller bearing of FIG. The graph which shows the result of a torque measurement test.

Explanation of symbols

1, 1a, 1b tapered roller bearing 2 inner ring 3 outer ring 2a, 3a raceway surface 4 tapered roller 4a taper hole 4b taper hole 4c stepped hole 4d stepped hole 4e grooved taper hole 5 cage 6, 7 annular part 8 column part 8a Tapered surface 9 Pocket 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 (7)

  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 tapered rollers arranged between the raceways of the inner ring and the outer ring, and these tapered rollers in pockets The retainer is composed of an annular portion that is continuous at both ends of the tapered roller, and a plurality of column portions that connect these annular portions, on both sides of the inner diameter surface of these column portions. In the roller bearing provided with the tapered surface on which the outer diameter surface of the tapered roller is in sliding contact, the through hole is formed in the axial center of the tapered roller, and the length dimension in the width direction of the tapered surface of the column portion is A tapered roller bearing characterized by being 5% or more of the average diameter of the roller and less than 11%.   2. The tapered roller bearing according to claim 1, wherein the through-hole is a tapered hole that gradually increases in diameter from the small-diameter end side toward the large-diameter end side.   2. The tapered roller bearing according to claim 1, wherein the through-hole is composed of at least two different diameter holes, a small diameter hole on the roller small diameter end side and a large diameter hole on the large diameter end side.   The tapered roller bearing according to any one of claims 1 to 3, wherein a step portion is formed in the middle of the through hole.   The tapered roller bearing according to any one of claims 1 to 4, wherein a spiral groove is formed on an inner peripheral surface of the through hole.   The tapered roller bearing according to any one of claims 1 to 5, wherein a thickness dimension of the column portion is 5% or more and less than 17% of an average diameter of the rollers.   The tapered roller bearing according to any one of claims 1 to 6, wherein the tapered roller bearing supports a power transmission shaft of a self-propelled vehicle.

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