JP2007120577A - Tapered roller bearing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent increase in the load capacity and damage of a raceway surface due to excess surface pressure by increasing the number of rollers, substantialize low torque without deteriorating the rigidity of a bearing, and suppress the occurrence of dragging torque. <P>SOLUTION: The tapered roller bearing comprises an inner ring 2, an outer ring 3, a plurality of tapered rollers 4 which are disposed between the inner ring 2 and the outer ring 3 and is capable of freely rolling the between those rings, and a retainer 5 circumferentially holding the tapered rollers 4 thereon at specified intervals. The retainer 5 is composed of an engineering plastic excellent in oil resistance and heat resistance. A tapered face 5d where the external-diameter face of the tapered rollers 4 slidingly contacts on both side of the inner-diameter face of a column part 5c formed between pockets 5e is provided. A length L of the tapered face 5d in the width direction is set to 5% or more and less than 11% of the average diameter of the tapered rollers 4. A window angle of the pockets 5e which is an angle formed by the tapered faces 5d, 5d facing each other is set to 55° or more and 80° or less. The roller factor γ is set to 0.94 or more. <P>COPYRIGHT: (C)2007,JPO&INPIT

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. 5 shows an example of the configuration of an automobile 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. 6 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 mission and fuel efficiency reduction. 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. 7 (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. In order to suppress drag torque on the outer diameter surface of the portion 62c, a recess 64 is formed to maintain a non-contact state between the outer diameter surface of the column portion 62c and the raceway surface 63a of the outer ring 63. As shown in detail in FIG. 7, 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. As a result, the retainer 62 may be deformed, or the retainer 62 may be deformed while the bearing 61 is rotating. If the rigidity of the retainer 62 is increased, the diameter of the retainer 62 is increased, which may cause an increase in torque due to sliding contact at the outer ring contact portion.

On the other hand, a conventional typical tapered roller bearing with a cage other than the tapered roller bearing described in Patent Document 4 avoids contact between the outer ring 71 and the cage 72 as shown in FIG. In order to secure the width and to obtain the appropriate column strength and smooth rotation of the cage 72, the roller coefficient γ (roller filling rate) defined by the following equation is usually designed to be 0.94 or less. (See Patent Document 2).
Roller coefficient γ = (Z · DA) / (π · PCD)
Here, Z: number of rollers, DA: roller average diameter, PCD: roller pitch circle diameter In FIG. 8, 73 is a tapered roller, 74 is a column surface, 75 is an inner ring, and θ is a window angle.

If an attempt is made to simply increase the roller filling rate while keeping the pocket size of the cage 72 as it is, the column 72a of the cage 72 becomes thin, and sufficient column strength cannot be ensured.

  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.

  The present invention relates to a tapered roller bearing comprising 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 predetermined circumferential intervals. The retainer is made of engineering plastic having excellent mechanical strength, oil resistance and heat resistance, and the outer diameter surface of the tapered roller slides on both sides of the inner diameter surface of the pillar portion formed between the pockets. A pocket window having a tapered surface that is in contact with each other, the length dimension of the tapered surface in the width direction being not less than 5% and less than 11% of the average diameter of the tapered roller, and an angle formed by the opposing tapered surface The angle is 55 ° or more and 80 ° or less, and the roller coefficient γ is 0.94 or more.

  The window angle is an angle formed by the guide surface of the pillar portion that abuts on the peripheral surface of one roller. By setting the window angle in the range of 55 ° to 80 °, a tapered roller bearing with a cage having a roller coefficient exceeding 0.94 is made possible. The reason why the window angle is set to 55 ° or more is to ensure a good contact state with the roller, and the reason why the window angle is set to 80 ° or less is that the pressing force in the radial direction is increased when the angle is further increased. This is because there is a risk that smooth rotation cannot be obtained even with a lubricating resin material. In a normal cage, the window angle is 25 ° to 50 °.

  The roller coefficient γ (roller filling ratio) is a parameter represented by (number of rollers × roller average diameter) / (π × PCD). When the average roller diameter is constant, the larger the value of γ, the greater the number of rollers. It means that there are many. In a conventional typical tapered roller bearing with a cage, the roller coefficient γ is usually designed to be 0.94 or less, so that the roller coefficient γ exceeds 0.94, This means that the roller filling rate and thus the bearing rigidity is high.

  In addition, the use of engineering plastics for the cage has the characteristics that the cage weight is lighter, self-lubricating, and the coefficient of friction is smaller than the iron plate cage.

  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.

  The thickness of the column portion is 5% or more and less than 17% of the average diameter of the tapered rollers. Thereby, the thickness of a pillar part can be made thin and the flow resistance of the lubricating oil with respect to rotation of a holder | retainer can be made small. 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.

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

  FIG. 10 shows the rigidity ratio (-●-) and torque ratio (-o-) when the roller pitch diameter (PCD) is changed in the tapered roller bearing. As shown in FIG. 16, when the PCD is reduced, the bearing torque is greatly reduced, but the bearing rigidity is not lowered so much as a result of calculating and confirming the elastic deformation amount of the roller. Therefore, if the PCD is reduced while the number of rollers is not reduced or increased, the torque can be reduced without reducing the rigidity.

  In the present invention, the PCD can be reduced while increasing the number of rollers by making the roller coefficient γ exceed 0.94. 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. Furthermore, since no drag torque is generated due to the contact of the cage, wear of the cage pocket can be minimized.

  In addition, the use of engineering plastics for the cage has the characteristics that the cage weight is lighter, self-lubricating, and the coefficient of friction is smaller than the iron plate cage. For this reason, combined with the effect of the lubricating oil present in the bearing, it becomes possible to suppress the occurrence of wear due to contact with the outer ring. Since these resins are lighter and have a smaller friction coefficient than steel plates, they are suitable for reducing torque loss and cage wear when starting the bearing.

  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.

  By making the thickness dimension of the column part 5% or more of the average diameter of the tapered roller 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, an embodiment of the present invention will be described with reference to FIGS. As shown in FIGS. 1A and 1B, the tapered roller bearing 1 of this embodiment has a conical raceway surface 2a, and a small flange portion 2b on the small diameter side of the raceway surface 2a and a large diameter side on the large diameter side. An inner ring 2 having a flange 2c, an outer ring 3 having a conical raceway surface 3a, and a plurality of tapered rollers 4 disposed between the raceway surface 2a of the inner ring 2 and the raceway surface 3a of the outer ring 3 so as to be able to roll. And a cage 5 that holds the tapered rollers 4 at equal intervals around the circumference.

  The cage 5 is integrally formed with a super engineering plastic such as PPS, PEEK, PA, PPA, or PAI. By using engineering plastics with excellent mechanical strength, oil resistance and heat resistance for the cage, the cage weight is lighter, self-lubricating, and the coefficient of friction is smaller than that of steel plate cages. Therefore, in combination with the effect of the lubricating oil present in the bearing, it becomes possible to suppress the occurrence of wear due to contact with the outer ring. In addition, these resins are lighter and have a smaller coefficient of friction than steel plates, and are therefore suitable for reducing torque loss and cage wear at the start of the bearing.

  Engineering plastics include general purpose engineering plastics and super engineering plastics. Typical examples are listed below, but these are examples of engineering plastics, and engineering plastics are not limited to the following.

[General-purpose engineering plastics] Polycarbonate (PC), polyamide 6 (PA6), polyamide 66 (PA66), polyacetal (POM), modified polyphenylene ether (m-PPE), polybutylene terephthalate (PBT), GF reinforced polyethylene terephthalate (GF) -PET), ultra high molecular weight polyethylene (UHMW-PE)

[Super Engineering Plastics] Polysulfone (PSF), Polyethersulfone (PES), Polyphenylene sulfide (PPS), Polyarylate (PAR), Polyamideimide (PAI), Polyetherimide (PEI), Polyetheretherketone ( PEEK), liquid crystal polymer (LCP), thermoplastic polyimide (TPI), polybenzimidazole (PBI), polymethylbenten (TPX), poly1,4-cyclohexanedimethylene terephthalate (PCT), polyamide 46 (PA46), polyamide 6T (PA6T), polyamide 9T (PA9T), polyamide 11,12 (PA11,12), fluororesin, polyphthalamide (PPA)

The tapered roller bearing 1 has a roller coefficient γ of γ> 0.94. The roller coefficient γ represents the filling rate of the roller and is defined by the following equation.
Roller coefficient γ = (Z · DA) / (π · PCD)
here,
Z: Number of rollers DA: Roller average diameter PCD: Roller pitch diameter.

  The cage 5 includes a small-diameter-side annular portion 5a, a large-diameter-side annular portion 5b, and 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. A plurality of pockets 5e are formed between the column portions 5c adjacent to each other in the circumferential direction so as to accommodate the tapered rollers 4 in a rollable manner. As shown in FIGS. 2 and 3, the cage 5 is provided with column surfaces (taper surfaces) 5 d on both sides of the inner diameter surface of the column portion 5 c so that the outer diameter surface of the tapered roller 4 is in sliding contact. It is an angle formed by the column faces 5d and 5d facing each other.

  As for the window angle θ which is an angle formed by the column faces 5d and 5d facing each other, the lower limit window angle θmin is 55 ° as shown in FIG. 2, and the upper limit window angle θmax is 80 ° as shown in FIG. In a typical tapered roller bearing with a cage in which the cage is separated from the outer ring as shown in FIG. 8, the window angle is about 50 ° at the maximum. In the present invention, the roller coefficient γ can be made 0.94 or more by setting the window angle to be larger. The reason why the lower limit window angle θmin is set to 55 ° or more is to ensure a good contact state with the roller, and when the window angle is less than 55 °, the contact state with the roller is deteriorated. That is, in order to make γ> 0.94 after securing the cage strength, a good contact state cannot be secured unless the window angle is 55 ° or more. Further, the upper limit window angle θmax is set to 80 ° or less because if it is further increased, the pressing force in the radial direction increases, and there is a risk that smooth rotation cannot be obtained even with a self-lubricating resin material. It is.

  In the cage 5, the length dimension L in the width direction of the tapered surface 5d is 5% or more of the average diameter D (see FIG. 1) 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 5d 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 5d. . When the length dimension L in the width direction of the tapered surface 5d 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 5d is larger than the width of the tapered surface 5d. Since there exists a possibility, it is preferable that the length dimension L of the taper surface 5d in the width direction shall be 5% or more of the average diameter of the tapered roller 4. In this embodiment, the length dimension L in the width direction of the tapered surface 5d is 7% of the average diameter D of the tapered rollers 4.

  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 the present invention, the PCD can be reduced while increasing the number of rollers by making the roller coefficient γ exceed 0.94. 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. Since the drag torque due to the contact of the cage 5 is not generated, the wear of the cage pocket 5e can be minimized.

  In addition, the use of engineering plastic for the cage 5 is characterized in that the cage weight is lighter, self-lubricating, and the coefficient of friction is smaller than the iron plate cage. For this reason, combined with the effect of the lubricating oil present in the bearing, it becomes possible to suppress the occurrence of wear due to contact with the outer ring. Since these resins are lighter and have a smaller friction coefficient than steel plates, they are suitable for reducing torque loss and cage wear when starting the bearing.

  Since the length dimension in the width direction of the tapered surface 5d is 5% or more of the average diameter of the tapered roller 4 and less than 11% (preferably 9% or less), the outer diameter surface of the tapered roller 4 and the tapered surface 5d A very large wedge space is not formed between the two. 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.

  By setting the thickness dimension of the column portion 5c to 5% or more and less than 17% of the average diameter of the tapered rollers 4, the thickness of the column portion 5c is reduced, and the flow resistance of the lubricating oil to the rotation of the cage 5 is reduced. The torque loss can be further reduced.

  FIG. 4 shows the results of bearing life tests. The bearing A is a typical conventional tapered roller bearing in which the cage and the outer ring are separated from each other. The bearing B is a conventional tapered roller bearing described in Patent Document 1. The bearing C is the tapered roller bearing of the present invention. The test was conducted under severe lubrication and overload conditions. As is clear from the figure, the bearing C according to the present invention has a roller coefficient of 0.96, which is the same as that of the bearing B, but its life time is about five times that of the bearing B. The dimensions of the bearings AC are φ45 × φ81 × 16 (unit mm), the number of rollers is 24 (bearings A), 27 (bearings B and C), and the oil film parameter Λ = 0.2.

  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, super engineering plastics such as PPS, PEEK, PA, PPA, and PAI are used for the cage material. However, if necessary, glass fiber is added to these resin materials or other engineering plastics for strength enhancement. Or what mix | blended carbon fiber etc. may be used.

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

  Tapered roller bearing (Example) using a cage whose length L of the tapered surface is 7% of the average diameter D of the tapered roller, and 13% of the average diameter D of the tapered roller having a tapered surface length L A tapered roller bearing (comparative example) using the conventional cage described above 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. 9 shows the results of the torque measurement test. The vertical axis of the graph of FIG. 9 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.

(A) is a fragmentary sectional view of the tapered roller bearing of the present invention, and (B) is a longitudinal sectional view of the roller bearing. It is a partial expanded sectional view of the tapered roller bearing whose window angle is a lower limit. It is a partial expanded sectional view of the tapered roller bearing whose window angle is an upper limit. It is a figure which shows the result of the lifetime test of a bearing. It is sectional drawing of a common motor vehicle transmission. It is sectional drawing which shows the differential of a common motor vehicle. Sectional drawing of the conventional tapered roller bearing which brought the retainer to the outer ring side. The partial expanded sectional view of another 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

DESCRIPTION OF SYMBOLS 1 Bearing 2 Inner ring 2c Large collar part 2b Small collar part 2a Raceway surface 3 Outer ring 3a Raceway surface 5 Cage 5a Small diameter side annular part 5b Large diameter side annular part 5c Column part 5d Tapered surface (column surface)
5f Protrusion

Claims (3)

In a tapered roller bearing, 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,
The retainer is made of engineering plastic having excellent mechanical strength, oil resistance, and heat resistance, and the tapered outer diameter surface is in sliding contact with both sides of the inner diameter surface of the column portion formed between the pockets. The tapered window has a width dimension in the width direction of 5% or more and less than 11% of the average diameter of the tapered rollers, and a pocket window angle that is an angle formed by the facing tapered surfaces. A tapered roller bearing having a roller coefficient of 55 ° to 80 ° and a roller coefficient γ of 0.94 or more. The tapered 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 tapered roller. 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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