JP5005207B2 - Tapered roller bearing - Google Patents

Description

  The present invention relates to a tapered roller bearing and can be applied to a bearing that supports a power transmission shaft such as a differential of a self-propelled vehicle or a transmission.

  FIG. 7 shows an example of the configuration of a vehicle transmission. This transmission is of a synchronous mesh type, and in the figure the left direction is the engine side and the right direction is the drive wheel side. A tapered roller bearing 43 is interposed between the main shaft 41 and the main drive gear 42. In this example, the outer ring raceway surface of the tapered roller bearing 43 is directly formed on the inner periphery of the main drive gear 42. The main drive gear 42 is rotatably supported with respect to the casing 45 by a tapered roller bearing 44. A clutch gear 46 is engaged and connected to the main drive gear 42, and a synchronization mechanism 47 is disposed in the vicinity of the clutch gear 46.

  The synchronizer 47 includes a sleeve 48 that moves in the axial direction (left and right in the figure) by the operation of a selector (not shown), a synchronizer key 49 that is mounted on the inner periphery of the sleeve 48 so as to be axially movable, A hub 50 engaged and connected to the outer periphery of the shaft 41, a synchronizer ring 51 slidably mounted on the outer periphery (cone portion) of the clutch gear 46, and a synchronizer key 49 are elastically attached to the inner periphery of the sleeve 48. A pressing pin 52 and a spring 53 are provided.

  In the state shown in the figure, the sleeve 48 and the synchronizer key 49 are held in the neutral position by the pressing pin 52. At this time, the main drive gear 42 idles with respect to the main shaft 41. On the other hand, when the sleeve 48 is moved to the left side in the axial direction, for example, by the operation of the selector, the synchronizer key 49 is moved to the left side in the axial direction following the sleeve 48 and the synchronizer ring 51 is moved to the clutch gear 46. Press against the inclined surface of the cone. As a result, the rotational speed of the clutch gear 46 decreases, and conversely, the rotational speed on the synchro mechanism 47 side is increased. When the rotational speeds of the two are synchronized, the sleeve 48 further moves to the left in the axial direction, meshes with the clutch gear 46, and the main shaft 41 and the main drive gear 42 are connected via the sync mechanism 47. . Thereby, the main shaft 41 and the main drive gear 42 rotate synchronously.

  FIG. 8 shows an example of the configuration of the automobile differential. This differential is connected to a propeller shaft (not shown), and a drive pinion 22 inserted into the differential case 21 meshes with a ring gear 24 attached to the differential gear case 23, and a pinion gear 25 attached to the inside of the differential gear case 23. However, the drive gear of the engine is transmitted from the propeller shaft to the left and right drive shafts by meshing with the side gear 26 coupled to the drive shaft (not shown) inserted into the differential gear case 23 from the left and right. 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. The differential case 21 is sealed with seal members 27a, 27b, and 27c, and the lubricating oil is stored inside. Each tapered roller bearing 1a, 1b rotates with its lower part immersed in this lubricating oil bath.

  The tapered roller bearing that can be used in the transmission and the differential has an outer ring having a conical raceway surface, a conical raceway surface, and a small flange portion and a large diameter side end portion at a small diameter side end portion of the raceway surface. An inner ring having a large collar portion, a plurality of tapered rollers arranged to roll between the raceway surface of the outer ring and the raceway surface of the inner ring, and a cage for holding the tapered rollers at equal intervals in the circumferential direction. I have.

  In such a tapered roller bearing, tapered surfaces on which the outer diameter surfaces of the tapered rollers are slidably contacted are provided on both sides of the inner diameter surface of the column portion, so that contact wrinkles are not generated on the outer diameter surface of the tapered rollers. Conventionally, the length of the tapered surface in the width direction is 11% to 20% of the average diameter of the tapered rollers.

  As described above, in the differential and the transmission, the tapered roller bearing rotates with the lower part immersed in the oil bath of this lubricating oil. As described above, in the tapered roller bearing used in the oil bath lubricated state, the wedge space formed by these surfaces is also formed between the outer diameter surface of the tapered roller 4 and the tapered surface of the columnar inner diameter surface of the cage 5. Lubricated with lubricating oil.

  Therefore, when the length dimension L in the width direction of the tapered surface of the cage is 11% to 20% of the average diameter of the tapered roller, it is between the outer diameter surface of the tapered roller and the tapered surface of the columnar inner diameter surface. A relatively 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, There is a problem that there is no escape space and there is resistance to rotation of the bearing, and torque loss increases. Further, in the tapered roller bearing that flows into the bearing as described above, the flow resistance of the lubricating oil with respect to the rotation of the cage also causes a torque loss that cannot be ignored.

Therefore, it is necessary to reduce torque loss due to the flow resistance of the lubricating oil in the tapered roller bearing in which the lubricating oil flows into the bearing. That is, it is necessary to reduce the oil flow resistance in order to reduce the torque. However, in order to significantly reduce the torque, it is necessary to change the bearing specifications so that the rolling viscous resistance is reduced. However, with the conventional torque reduction technique (see Patent Documents 1 to 3), it is possible to reduce the torque without reducing the rated load, but the bearing rigidity is somewhat reduced.
JP 09-096352 A Japanese Patent Laid-Open No. 11-0210765 JP 2003-343552 A JP 2003-28165 A

  On the other hand, low-viscosity oil tends to be used for automobile transmissions in recent years for the purpose of AT / CVT missions, fuel efficiency reduction, etc., but in environments where low-viscosity oil is used, the oil temperature is low. When unfavorable conditions such as high, low oil volume, preload loss occur, etc., surface origin separation due to poor lubrication may occur on the raceway surface of the inner ring with high surface pressure. .

  As a countermeasure for short life due to this surface-origin separation, reduction of the maximum surface pressure is a direct and effective solution. In order to reduce the maximum surface pressure, the bearing dimensions are changed, or if the bearing dimensions are not changed, the number of rollers of the bearing is increased. In order to increase the number of rollers without reducing the roller diameter, the pocket interval of the cage must be narrowed. For this purpose, it is necessary to enlarge the pitch circle of the cage and bring it closer to the outer ring side as much as possible.

  As an example in which the cage is brought into contact with the inner surface of the outer ring, there is a tapered roller bearing shown in FIG. 9 (see Patent Document 4). The tapered roller bearing 61 guides the cage 62 by sliding the outer peripheral surface of the small-diameter side annular portion 62 a and the outer peripheral surface of the large-diameter side annular portion 62 b with the inner surface of the outer ring 63. A recess 64 is formed in the outer diameter surface of the portion 62c to suppress drag torque, and the non-contact state between the outer diameter surface of the column portion 62c and the raceway surface 63a of the outer ring 63 is maintained. As shown in detail in FIG. 10, the retainer 62 has a small-diameter-side annular portion 62a, a large-diameter-side annular portion 62b, and a small-diameter-side annular portion 62a and a large-diameter-side annular portion 62b connected in the axial direction to the outer diameter surface. And a plurality of column parts 62c in which recesses 64 are formed. A plurality of pockets 66 are provided between the column portions 62c for accommodating the tapered rollers 65 in a rollable manner. The small-diameter-side annular portion 62a is provided with a flange portion 62d that extends integrally on the inner-diameter side.

  In the tapered roller bearing 61 described in Patent Document 4, since the recess 64 is provided in the column portion 62 c of the cage 62, the plate thickness is inevitably thinned, the rigidity of the cage 62 is reduced, and the stress during assembly of the bearing 61 is reduced. Due to this, there is a possibility that the cage 62 is deformed or the cage 62 is deformed while the bearing 61 is rotating. Further, since the outer peripheral surface of the small-diameter side annular portion 62a and the outer peripheral surface of the large-diameter side annular portion 62b of the cage 62 are in sliding contact with the inner surface of the outer ring 63, there is a problem that the torque is increased accordingly.

  The object of the present invention is to increase the number of rollers to prevent an early breakage due to an increase in load capacity and excessive surface pressure of the raceway surface, and to realize a reduction in torque without reducing bearing rigidity. An object of the present invention is to provide a tapered roller bearing capable of suppressing the generation of drag torque.

A tapered roller bearing according to the present invention includes an inner ring, an outer ring, a plurality of tapered rollers arranged to roll between the inner ring and the outer ring, and a cage having a pocket for holding the tapered rollers at a predetermined circumferential interval. A cone formed on the outer diameter surface of the cage with a convex shape toward the inner diameter surface of the outer ring and forming a plurality of projections at predetermined intervals around the inner diameter surface of the outer ring. In the roller bearing, the cage is disposed close to the inner diameter surface of the outer ring, and the protrusion of the cage is provided at the center in the circumferential direction of the outer diameter surface of the column portion formed between the pockets. and, on both sides of the inner surface of the pillar portion, and the outer diameter surface is in sliding contact before Symbol tapered rollers, provided with a tapered surface does not reach the outer diameter surface of the pillar portion, for escape securing the lubricating oil, The length dimension in the width direction of the tapered surface is 5% or more of the average diameter of the tapered rollers. , And less than 11%, more for flow resistance reduction of the lubricating oil, the thickness of the pillar portion, at least 5% of the average diameter of the tapered rollers is obtained by less than 17%.

  By making the length dimension of the tapered surface in the width direction less than 11% (preferably 9% or less) of the average diameter of the tapered roller, a very large wedge space is formed between the outer diameter surface of the tapered roller and the tapered surface. Not formed. If the length dimension in the width direction of the tapered surface is less than 5% of the average diameter of the tapered roller, the elastic contact area between the outer diameter surface of the tapered roller and the tapered surface may be larger than the width of the tapered surface. The length dimension of the tapered surface in the width direction is preferably 5% or more of the average diameter of the tapered rollers.

  By forming the protrusion, a minute gap between the retainer and the outer ring is maintained by the dynamic pressure of the wedge-shaped oil film formed between the protrusion and the inner diameter surface of the outer ring when the tapered roller bearing rotates. Torque loss and damage to the cage or outer ring raceway surface are prevented. Accordingly, the outer diameter surface of the cage can be brought as close as possible without contacting the inner diameter surface of the outer ring, and the maximum surface pressure generated on the inner ring raceway surface can be increased by increasing the number of rollers accommodated in the cage without increasing the bearing torque. Can be suppressed. Further, since the drag torque due to the contact of the cage is not generated, the wear of the cage pocket portion can be minimized.

The thickness of the pillar portion, at least 5% of the average diameter of the tapered rollers, by less than 17%, by reducing the thickness of the column part, reduce the flow resistance of the lubricating oil to the rotation of the cage can do. If the thickness dimension of the column part is less than 5% of the average diameter of the tapered roller, the rigidity of the cage cannot be sufficiently secured. Therefore, the thickness dimension of the column part is set to 5% or more of the average diameter of the tapered roller. Is preferred.

  The protrusion is formed in a cross-section arc shape on the outer diameter surface of the pillar portion of the cage, the radius of curvature of the arc is smaller than the radius of the outer ring raceway surface, and the width dimension of the projection portion is the width of the pillar portion of the cage. It was 50% or more of the dimension. As a result, a good wedge-shaped oil film is formed between the inner ring surface of the outer ring and the outer ring is kept out of contact with the dynamic pressure of the wedge-shaped oil film when the bearing rotates.

  Each tapered roller bearing described above is suitable for supporting a power transmission shaft of a self-propelled vehicle.

  In the tapered roller bearing of the present invention, the length dimension in the width direction of the tapered surface is 5% or more and less than 11% (preferably 9% or less) of the average diameter of the tapered roller. A very large wedge space is not formed between the taper surface and the taper surface. For this reason, 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.

  A plurality of protrusions that protrude toward the inner peripheral surface of the outer ring are formed on the outer peripheral surface of the cage of the tapered roller bearing at predetermined intervals around the outer ring, so that the roller outer diameter surface is brought close to the inner diameter surface of the outer ring. Even if the number is increased, a good lubricating action by the wedge-shaped oil film can be obtained between the protrusion and the inner peripheral surface of the outer ring.

  FIG. 12 shows the rigidity ratio (− ● −) and torque ratio (− ◯ −) when the tapered roller pitch diameter (PCD) is changed in the tapered roller bearing. As shown in FIG. 12, when the PCD is reduced, the bearing torque is greatly reduced, but the bearing rigidity is not reduced so much as a result of calculating and confirming the amount of elastic deformation of the tapered roller. Therefore, the torque can be reduced without reducing the rigidity by reducing the PCD while decreasing or increasing the number of rollers.

  In the present invention, the roller PCD is made small while increasing the number of rollers by forming a plurality of protrusions that are convex toward the inner peripheral surface of the outer ring on the outer peripheral surface of the retainer of the tapered roller bearing at predetermined circumferential intervals. I was able to do it. For this reason, a reduction in torque can be realized without reducing the bearing rigidity. Also, by increasing the number of rollers, not only the load capacity is increased, but the maximum surface pressure of the inner and outer ring raceway surfaces can be reduced by increasing the number of rollers without impairing the torque characteristics of the bearing. Even when adverse conditions such as a small amount of oil and occurrence of preload loss result in severe lubrication conditions, it is possible to prevent surface-origin separation having an extremely short life, particularly on the inner ring raceway surface.

  In addition, by setting the thickness of the column portion to 5% or more and less than 17% of the average diameter of the tapered rollers, the thickness of the column portion is reduced, and the flow resistance of the lubricating oil to the rotation of the cage is reduced. Thus, torque loss can be further reduced.

  The shape of the protrusion is an arc of cross section with a radius of curvature smaller than the radius of the outer ring raceway surface, and the width of the protrusion is 50% or more of the width of the cage pillar, so that the inner diameter of the outer ring is A good wedge-shaped oil film is formed between the surface and the non-contact state between the cage and the outer ring by the dynamic pressure of the wedge-shaped oil film. For this reason, it is possible to stably prevent torque loss and damage to the cage or the outer ring raceway surface.

  Embodiments of the present invention will be described below with reference to the drawings.

As shown in FIGS. 1 and 4, the tapered roller bearing 1 of this embodiment includes an inner ring 2, an outer ring 3, a tapered roller 4, and a cage 5. The inner ring 2 has a conical track surface 2a on the outer periphery, and the outer ring 3 has a conical track surface 3a on the inner periphery. A plurality of tapered rollers 4 are interposed between the raceway surface 2a of the inner ring 2 and the raceway surface 3a of the outer ring 3 so as to be freely rollable. The tapered roller 4 is accommodated in a pocket 5d formed in the cage 5. Each tapered roller 4 is restricted from moving in the axial direction by a small brim 2 b and a large brim 2 c provided on both sides of the raceway surface 2 a of the inner ring 2.

  The cage 5 is a press-worked product formed by pressing from a steel plate (steel pipe) such as an SPCC steel plate, for example, as shown in FIG. 3, a small-diameter side annular portion (small-diameter ring portion) 5a and a large-diameter side annular portion. (Large-diameter ring portion) 5b, a plurality of column portions 5c that connect the small-diameter side annular portion 5a and the large-diameter side annular portion 5b in the axial direction, and a tapered roller provided between the column portions 5c adjacent in the circumferential direction. And a plurality of pockets 5d for accommodating 4 in a rollable manner. The small-diameter-side annular portion 5a is provided with a flange portion 5e that extends integrally on the inner-diameter side.

  As shown in FIGS. 1 to 3, a protruding portion 5 f that is convex toward the outer ring raceway surface is integrally formed on the outer diameter surface of the column portion 5 c. As shown in FIG. 2, the projecting portion 5f has a circular cross-sectional contour shape of the column portion 5c. The arc-shaped curvature radius R2 is smaller than the outer ring raceway radius R1. This is to form a good wedge-shaped oil film between the protrusion 5f and the outer ring raceway surface. Preferably, the curvature radius R2 of the protrusion is formed to be about 70 to 90% of the outer ring raceway radius R1. Good. If it is less than 70%, the opening angle of the wedge-shaped oil film becomes too large, and the dynamic pressure decreases. If it exceeds 90%, the inlet angle of the wedge-shaped oil film becomes too small, and the dynamic pressure similarly decreases. Further, the lateral width W2 of the protruding portion 5f is desirably formed to be 50% or more of the lateral width W1 of the column portion 5c (W2 ≧ 0.5 × W1). This is because if it is less than 50%, a sufficient height of the protrusion 5f for forming a good wedge-shaped oil film cannot be secured. Since the outer ring raceway surface radius R1 continuously changes from the large diameter side to the small diameter side, the curvature radius R2 of the projection 5f is accordingly adjusted from the large curvature radius R2 of the large diameter side annular portion 5b to the small diameter side. It is made to change continuously to the small curvature radius R2 of the annular part 5a.

The surface of the cage 5, particularly the outer diameter surface of the cage 5, should be as smooth as possible. That is, during the rotation of the tapered roller bearing 1, a wedge-like oil film is formed between the protrusion 5f on the outer diameter surface of the cage 5 and the outer ring raceway surface, and the dynamic pressure action causes the outer diameter surface or the protrusion 5f of the cage 5. Does not come into contact with the outer ring raceway surface, but if severe lubrication conditions occur before the wedge roller oil film is formed due to the low rotational speed immediately after the tapered roller bearing 1 rotates, the outer diameter surface or protrusion of the cage 5 There is a possibility that the portion 5f contacts the outer ring raceway surface. In preparation for such a case, the friction coefficient is reduced as much as possible by coating the outer diameter surface of the cage 5 with, for example, molybdenum disulfide (MoS ₂ ) coating or barrel polishing. It is better to take treatment. That is, by performing such a smoothing process, it is possible to reduce torque loss and cage wear at the start of the bearing.

  The cage 5 may be a resin-made cage 15 (see FIG. 5) in addition to a steel plate press product. Similarly to the retainer 5 made of a steel plate press, a protrusion 15 f is integrally formed on the outer diameter surface of the column portion 15 c of the resin retainer 15. As the type of resin, it is desirable to use super engineering plastics such as PPS, PEEK, PPA, or polyamide resin in consideration of oil resistance when used in an automobile transmission. Since the resin cage 15 has a feature that the weight is lighter and the friction coefficient is smaller than the steel plate press cage 5, the resin cage is lighter and has a smaller friction coefficient than the steel plate press cage, It is suitable for reducing torque loss and cage wear when starting the bearing. Further, the steel plate press cage is advantageous in that it is suitable for extending the bearing life because it has high rigidity and wear resistance. In the tapered roller bearing shown in FIG. 5, the same components as those of the tapered roller bearing shown in FIG. In FIG. 5, 15d indicates a pocket, and 15e indicates a buttocks.

  Since the tapered roller bearing 1 of the present invention is configured as described above, when the bearing 1 rotates and the cage 5 (15) begins to rotate, the outer ring raceway surface and the protrusion 5f of the cage 5 (15). A wedge-shaped oil film is formed between the two. Since this wedge-shaped oil film generates a dynamic pressure substantially proportional to the rotational speed of the bearing 1, even if the pitch circle diameter (PCD) of the cage 5 (15) is increased and brought close to the outer ring raceway surface, the bearing 1 becomes large. It is possible to rotate without causing wear or torque loss, and it is possible to increase the number of rollers without difficulty.

As shown in FIG. 6B, the retainer 5 is provided with tapered surfaces 18 on both sides of the inner diameter surface of the column portion 5c so that the outer diameter surfaces of the tapered rollers 4 are in sliding contact with each other. The length dimension L is 5% or more of the average diameter D of the tapered rollers 4 and less than 11% (preferably 9% or less). By setting the length dimension L in the width direction of the tapered surface 18 to less than 11% of the average diameter of the tapered roller 4, a very large wedge space is not formed between the outer diameter surface of the tapered roller 4 and the tapered surface 18. . When the length dimension L in the width direction of the tapered surface 18 is less than 5% of the average diameter of the tapered roller, the elastic contact region between the outer diameter surface of the tapered roller 4 and the tapered surface 18 becomes larger than the width of the tapered surface 18. Therefore, it is preferable that the length L in the width direction of the tapered surface 18 is 5% or more of the average diameter of the tapered rollers 4. In this embodiment, the length dimension L in the width direction of the tapered surface 18 is 7% of the average diameter D of the tapered rollers 4. Further, in FIG. 6, for the sake of simplification of the drawing, the illustration of the protrusion 5 f is omitted, but the protrusion 5 f is actually provided. The tapered surface 18 is set so as not to reach the outer diameter surface of the column portion 5c as shown in FIG.

  Further, the thickness dimension T of the column part 5c is set to 5% or more and less than 17% of the average diameter D of the tapered rollers 4. Thereby, the flow resistance of the lubricating oil with respect to the rotation of the cage 5 can be reduced. In addition, if the thickness dimension T of the column part 5c is less than 5% of the average diameter of the tapered roller, the rigidity of the cage 5 cannot be sufficiently secured. Therefore, the thickness dimension T of the column part 5c is equal to the average diameter of the tapered roller 4. 5% or more is preferable. In this embodiment, the thickness dimension T of the column part 5 c is 10% of the average diameter D of the tapered rollers 4. In addition, the thickness dimension T of the column part 5c is thickness including the protrusion part 5f.

  In the tapered roller bearing of the present invention, the length dimension L in the width direction of the tapered surface 18 is 5% or more of the average diameter D of the tapered roller 4 and less than 11% (preferably 9% or less). No large wedge space is formed between the outer diameter surface 4 and the tapered surface 18. For this reason, 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.

  Since a plurality of protrusions 5f that are convex toward the inner peripheral surface of the outer ring are formed at predetermined intervals on the outer peripheral surface of the retainer 5 of the tapered roller bearing, the outer diameter surface of the cage is brought close to the inner diameter surface of the outer ring. Even if the number of rollers accommodated is increased, a good lubricating action by the wedge-shaped oil film can be obtained between the protrusion 5f and the inner peripheral surface of the outer ring.

  By forming a plurality of protruding portions 5f that protrude toward the inner peripheral surface of the outer ring 3 on the outer peripheral surface of the retainer 5 of the tapered roller bearing at predetermined circumferential intervals, the roller PCD can be reduced while increasing the number of rollers. I did it. For this reason, a reduction in torque can be realized without reducing the bearing rigidity. Also, by increasing the number of rollers, not only the load capacity is increased, but the maximum surface pressure of the inner and outer ring raceway surfaces can be reduced by increasing the number of rollers without impairing the torque characteristics of the bearing. Even when adverse conditions such as a small amount of oil and occurrence of preload loss result in severe lubrication conditions, it is possible to prevent surface-origin separation having an extremely short life, particularly on the inner ring raceway surface. Further, the generation of drag torque due to the contact of the cage 5 can be suppressed, and wear of the cage pocket 5d can be minimized.

  Moreover, the thickness dimension T of the column part 5c is 5% or more and less than 17% of the average diameter of the tapered rollers, so that the thickness of the column part 5c is reduced and the lubricating oil against rotation of the cage 5 is reduced. The flow resistance can be reduced, and torque loss can be further reduced.

  The shape of the protrusion 5f is an arc of a cross section with a radius of curvature smaller than the radius of the outer ring raceway surface, and the width of the protrusion 5f is 50% or more of the width of the pillar 5c of the cage 5, thereby A good wedge-shaped oil film is formed between the outer ring inner diameter surface and the non-contact state between the cage 5f and the outer ring 3 by the dynamic pressure of the wedge-shaped oil film during rotation. For this reason, it is possible to stably prevent torque loss and damage to the cage or the outer ring raceway surface.

  Although the embodiments of the present invention have been described above, the present invention is not limited to the above embodiments and can be variously modified. For example, in the above-described embodiment, the protruding portion 5f (15f) is formed on the outer diameter surface of the column portion 5c (15c), but in addition to this, the small-diameter side annular portion 5a and the large-diameter side annular portion of the cage 5 (15). It can also be formed on the outer diameter surface of 5b.

  The tapered roller bearing 1 according to the present invention can be used for automobile transmissions and differentials, but it can also be used for applications other than automobile gear devices.

  6A and 6B, a tapered roller bearing (Example) using a cage 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 dimension L of 13% of the average diameter D of the tapered roller was prepared. Each tapered roller bearing had 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 an Example and a comparative example, the torque measurement test using the vertical torque tester was done. The test conditions are as follows.
Axial load: 300kgf
Rotational speed: 300-2000 rpm (100 rpm pitch)
Lubrication condition: oil bath lubrication (lubricating oil: 75W-90)

  FIG. 11 shows the results of the torque measurement test. The vertical axis of the graph in FIG. 11 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 as small as 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.

It is a fragmentary sectional view of the tapered roller bearing which concerns on this invention. It is sectional drawing of the pillar part of a holder | retainer. It is a fragmentary perspective view of a holder | retainer. (A) is a longitudinal cross-sectional view of a tapered roller bearing using a steel plate press cage, and (B) is a cross-sectional view taken along line BB in (A). (A) is a longitudinal cross-sectional view of the tapered roller bearing using the resin cage, and (B) is a cross-sectional view taken along the line BB of (A). 1 shows the cage of FIG. 1, (A) is a developed plan view, and (B) is a sectional view taken along line XX of (A). FIG. It is a fragmentary sectional view of the transmission of a car. It is sectional drawing which shows the differential of a motor vehicle. It is a fragmentary sectional view of the conventional tapered roller bearing. It is a perspective view of the retainer of the conventional tapered roller bearing. It is a graph which shows the result of a torque measurement test. It is a diagram showing the change of a rigidity ratio and a torque ratio when changing a tapered roller pitch diameter (PCD) in a tapered roller bearing.

Explanation of symbols

2 Inner ring 2a Raceway surface 3 Outer ring 3a Raceway surface 5, 15 Cage 5a, 15a Small diameter ring part (small diameter side annular part)
5b, 15b Large-diameter ring part (large-diameter side annular part)
5c, 15c Pillar part 5d Pocket 5f, 15f Protrusion part 5e, 15e ridge part 18 taper surface

Claims (3)

An inner ring, an outer ring, a plurality of tapered rollers arranged to roll between the inner ring and the outer ring, and a cage having a pocket for holding the tapered rollers at a predetermined circumferential interval. In the tapered roller bearing in which a plurality of protrusions forming a minute gap between the inner surface of the outer ring and the inner surface of the outer ring are formed at predetermined intervals on the radial surface.
The retainer is disposed close to the inner diameter surface of the outer ring, and the protrusion of the retainer is provided at the center in the circumferential direction of the outer diameter surface of the column portion formed between the pockets, and on both sides of the inner surface of the pillar portion, and the outer diameter surface is in sliding contact before Symbol tapered rollers, provided with a tapered surface does not reach the outer diameter surface of the pillar portion, for escape securing the lubricating oil, of the tapered surface The length dimension in the width direction is set to 5% or more and less than 11% of the average diameter of the tapered roller, and the thickness dimension of the column portion is set to be equal to that of the tapered roller in order to reduce the flow resistance of the lubricating oil . Tapered roller bearings characterized in that the average diameter is 5% or more and less than 17%.   The protrusion is formed in a cross-section arc shape on the outer diameter surface of the pillar portion of the cage, the radius of curvature of the arc is smaller than the radius of the outer ring raceway surface, and the width dimension of the projection portion is the width of the pillar portion of the cage. The tapered roller bearing according to claim 1, wherein the tapered roller bearing is 50% or more of a dimension.   The tapered roller bearing according to claim 1 or 2, wherein a power transmission shaft of the self-propelled vehicle is supported.

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