JP5128112B2 - Tapered roller bearing - Google Patents

Description

  The present invention relates to a tapered roller bearing.

  The driving force of the engine in the automobile is transmitted to the wheels via a power transmission system including any or all of a transmission, a propeller shaft, a differential, and a drive shaft.

  In this power transmission system, a tapered roller bearing having a high load capacity against a radial load and excellent in impact resistance is often used as a bearing for supporting the shaft. As shown in FIG. 3, the tapered roller bearing generally has an inner ring 2 having a conical raceway surface 1 on the outer peripheral side, an outer ring 4 having a conical raceway surface 3 on the inner peripheral side, and an inner ring 2. And a plurality of tapered rollers 5 disposed between the outer ring 4 and the outer ring 4, and a retainer 6 that holds the tapered rollers 5 at a predetermined circumferential interval.

  As shown in FIG. 4, the retainer 6 includes a pair of annular portions 6a and 6b and a column portion 6c that connects the annular portions 6a and 6b, and is formed between adjacent column portions 6c along the circumferential direction. The tapered roller 5 is accommodated in the pocket 6d.

  In this tapered roller bearing, the tapered roller 5 and the raceway surfaces 1 and 3 of the inner and outer rings 2 and 4 are in line contact, and the inner and outer ring raceway surfaces 1 and 3 and the roller center O are at one point on the axis P (see FIG. (Not shown).

  For this reason, when a load acts, the tapered roller 5 is pressed to the large end side. In order to receive this load, a flange portion 7 that protrudes toward the outer diameter side is provided on the larger diameter side of the inner ring 2. In addition, a flange 8 that protrudes also to the small end side of the inner ring 2 is provided so that the tapered roller 5 does not fall off to the small end side before the bearing is assembled in a machine or the like.

  Along with the expansion of the interior space, the engine room is shrinking, the output of the engine is increased, and the transmission is multistaged to improve fuel efficiency. As a result, the usage environment of the tapered roller bearings used therein has become severer year by year. Yes. In order to satisfy the life of the bearing in the usage environment, it was necessary to further extend the life of the bearing.

  Against the above background, it can be proposed to increase the load capacity with the same dimensions and increase the life of the bearing by increasing the number of rollers or increasing the roller length. However, in the current structure, as described above, the inner ring is provided with the flange portion (small rod) 8 on the small diameter side of the raceway surface for reasons of assembling the bearing. For this reason, there is a restriction by the flange portion 8 for increasing the length of the tapered roller 5. Each tapered roller 5 is supported by the cage 6 as described above, and the column portion 6c of the cage 6 is interposed between adjacent tapered rollers 5 along the circumferential direction. For this reason, there is a restriction by the column portion 6c even for the roller whose number of rollers is increased. Thus, there has been a limit in increasing the load capacity in the prior art.

Conventionally, there is an inner ring in which a small-diameter side collar (small collar) is omitted (Patent Document 1). If the collar portion on the small diameter side in the inner ring is omitted, the length of the tapered roller in the axial direction can be increased by that amount, and the load capacity can be increased.
JP 2002-54638 A

  However, if the flange portion 8 on the small diameter side in the inner ring 2 is omitted, the tapered roller 5 falls off to the small end side before being incorporated into a machine or the like. Therefore, in the device described in Patent Document 1, the cage is provided with a hook portion that engages with the flange portion 7 on the large diameter side so that the tapered roller 5 does not fall.

  However, since the bearing described in Patent Document 1 is made of iron, when the hook portion is formed, a bending process for forming the hook portion is required, and the manufacturing process is increased and the manufacturing process is increased. The cost increases and the manufacturing time becomes longer. Moreover, wear powder is generated in the iron cage, and the wear powder may cause a decrease in lubricity.

  In addition, in the thing of patent document 1, as mentioned above, on the assumption that a cage | basket is iron, it aims at aiming at size reduction and weight reduction in such a bearing.

  In view of the above problems, the present invention provides a tapered roller bearing capable of improving productivity and achieving a long life.

The 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 resin cage that holds the tapered rollers at predetermined circumferential intervals. A tapered roller bearing provided with a flange that protrudes toward the outer diameter side on the large diameter side of the inner ring and that receives the large end surface of the tapered roller forms a raceway surface that reaches the small diameter end from the flange, and holds the holding An engagement portion that protrudes in the inner diameter direction and engages with the flange portion of the inner ring is provided on the large diameter side of the vessel, and the inner diameter end of the engagement portion is further on the outer diameter side than the outer diameter edge of the inner diameter side of the pocket. In addition, the engaging portion is set to have a width dimension smaller than the minimum width dimension of the pocket so that the engaging portion can be accommodated in a pocket at a corresponding position when viewed from the axial direction.

  According to the tapered roller bearing of the present invention, the raceway surface of the inner ring reaches the small-diameter end from the flange part, and the small-diameter side flange part and the slack part of the inner ring that existed in the prior art are also omitted. For this reason, the raceway surface can be made large only in this omitted collar portion and fillet portion. Moreover, since the engaging part which engages with the collar part of the inner ring is provided in the cage, the tapered roller can be prevented from falling off to the small end side. In addition, since the engaging portion is disposed so as to be accommodated in the corresponding pocket when viewed from the axial direction, the molding die is not affected by the engaging portion when the cage made of resin is formed. Can be removed.

  A cutout portion can be provided on the outer diameter surface of the flange portion, and the engagement portion can be locked to the cutout portion. As a result, it is possible to improve the engagement to the buttock side. In addition, since the engaging portions are arranged so as to be accommodated in the corresponding pockets when viewed from the axial direction, the depth of the notch portions with which the engaging portions engage can be reduced, and the strength of the collar portion can be prevented from being lowered.

  In the tapered roller bearing of the present invention, the flange portion on the small diameter side of the inner ring, which has existed in the prior art, is omitted. For this reason, this omission part and weight reduction can be achieved. In addition, the raceway surface is enlarged only in the small diameter side flange portion and the omitted portion which are omitted, whereby the axial center length of the tapered roller can be increased, the load capacity can be improved, and a longer life can be achieved. it can. Further, since the engaging portion of the cage engages with the flange portion of the inner ring, the tapered roller can be prevented from falling off to the small end side, and the inner ring, the tapered roller and the cage are handled as an assembly (assembly unit body). It is possible to improve the assemblability (productivity) of the entire bearing.

  In addition, when the resin cage is molded, the molding die can be pulled out without being affected by the engaging portion. For this reason, the improvement of manufacturability can be aimed at, and this tapered roller bearing can be manufactured stably and reliably. In addition, since the cage is made of resin, wear powder due to wear does not occur, and there is no possibility of causing a decrease in lubricity due to the wear powder, thereby extending the life.

  By engaging the engaging part with the notch part of the flange part, the engagement of the engaging part to the flange part side can be improved, and the shaft of the engaging part on the large diameter side of the inner ring can be achieved. Protrusion outward in the direction can be avoided and downsizing can be achieved. Furthermore, the depth of the notch part with which the engaging part engages can be reduced, and the strength of the collar part can be prevented from being lowered, thereby preventing a lack of roller bearing strength due to the collar part and receiving the tapered roller stably. be able to.

  In addition, the cage made of resin is lighter than the steel plate, is self-lubricating, and has a small coefficient of friction. Therefore, combined with the effect of the lubricating oil in the bearing, It is possible to suppress the occurrence of wear due to the contact of. Further, since the resin cage is light and has a small coefficient of friction, it is suitable for reducing torque loss and cage wear at the time of starting the bearing.

  Hereinafter, an embodiment of the present invention will be described with reference to FIGS.

  FIG. 1 shows a tapered roller bearing according to the present invention. The tapered roller bearing includes an inner ring 21, an outer ring 22, a plurality of tapered rollers 23 disposed between the inner ring 21 and the outer ring 22 so as to be freely rollable, And a resin-made cage 24 that holds the tapered rollers 23 at a predetermined circumferential interval.

  The inner ring 21 has a conical raceway surface 25 on its outer diameter surface, and a flange portion 26 is formed on the larger diameter side of the raceway surface 25 so as to protrude toward the outer diameter side. That is, the raceway surface 25 is formed from the flange portion 26 to the small diameter end, and does not have the flange portion on the small diameter side like the inner ring of the conventional tapered roller bearing. A corner portion 27 between the raceway surface 25 and the flange portion 26 is formed with a thin portion 27. The flange portion 26 in this case is a large flange that receives the axial load through the tapered roller 23 and guides the tapered roller 23 to rotate. Further, the conventionally provided gavel does not play a special role during the rotation of the bearing, and such a thing is omitted in the present invention.

  Further, the inner surface (that is, the end surface on the small diameter side) 26 a of the flange portion 26 is inclined by a predetermined angle with respect to a plane orthogonal to the bearing axis P. That is, as shown in FIG. 1, when fitted to the raceway surface 25 of the inner ring 21, the peripheral wall 23a of the roller 23 contacts (contacts) the raceway surface 25, and the large end surface 23b of the tapered roller 23 has a flange portion. The angle formed by the raceway surface 25 and the inner surface 26 a of the flange portion 26 is adjusted to the angle formed by the peripheral wall 23 a of the roller 23 so as to contact (abut) the inner surface 26 a of the roller 26.

  The outer ring 22 has a tapered raceway surface 30 on its inner diameter surface, and a plurality of tapered rollers 23 held by a cage 24 roll on the raceway surface 30 and the raceway surface 25 of the inner ring 21. .

  For this reason, since the inner ring 21 does not have a flange on the small diameter side, the small end surface 23c of the tapered roller 23 can be extended until it reaches the small diameter side end surface 21b of the inner ring 21, as shown in FIG.

  As shown in FIGS. 1 and 2, the retainer 24 includes a pair of annular portions 24a and 24b and column portions 24c that extend in the roller center O direction at equal circumferential positions and connect the annular portions 24a and 24b. With. And the tapered roller 23 is rotatably accommodated in the pocket 24d partitioned by the column parts 24c and 24c which adjoin along the circumferential direction.

  The large-diameter-side annular portion 24a includes a large-diameter short cylindrical portion 35 and an engaging portion 36 that protrudes in the inner diameter direction, and the engaging portions 36 are disposed at a pitch of 90 degrees along the circumferential direction. It is comprised by the locking piece 36a. As shown in FIG. 2, when viewed from the axial direction, the locking piece 36a is sized to fit within one corresponding pocket 24d. In this case, the inner diameter end 39 of the engaging portion 36 is positioned on the outer diameter side from the outer diameter edge 37a of the inner diameter side 37 of the pocket 24d. Further, the width dimension W of the engaging portion 36 is set smaller than the minimum width dimension W1 of the pocket 24d.

  And the notch part 38 is formed in the large diameter side of the outer diameter surface 26c of the collar part 26 of the inner ring | wheel 21, and the said engaging part 36 is engaged with this notch part 38. As shown in FIG. For this reason, as the engaging portion 36, the inner diameter end 39 is positioned on the outer diameter side from the outer diameter edge 37 a of the inner diameter side 37 of the pocket 24 d and at the inner diameter side than the outer diameter surface 26 c of the flange portion 26 of the inner ring 21. Is located. In this case, the notch inner diameter end 38a of the notch 38 is on the outer diameter side by the gap H from the outer diameter edge 37a of the inner diameter side 37 of the pocket 24d. Further, the outer surface 40 of the engaging portion 36 does not protrude outward in the axial direction from the end surface 21 a on the large diameter side of the inner ring 21.

  The cage 24 is preferably made of engineering plastic. Engineering plastic (engineering plastic) is a synthetic resin that has excellent heat resistance and can be used in fields where strength is required. Resins with increased heat resistance and strength are called super engineering plastics. Rather than technical classification, there is an aspect of classification according to commercial strategy. In general, a resin having a heat-resistant temperature of 100 ° C. or higher and a certain mechanical strength is called an engineering plastic. Typical examples include polyacetal (POM), polyamide (PA), polycarbonate (PC), modified polyphenylene ether (m-PPE), and polybutylene terephthalate (PPB), which are known as five general-purpose engineering plastics. . GF reinforced polyethylene terephthalate (GF-PET) and ultra high molecular weight polyethylene (UHPE) are also classified as engineering plastics. Further, among engineering plastics, a resin having a heat resistant temperature of 150 ° C. or higher is called a super engineering plastic, and this super engineering plastic can also be used for the cage 24. Typical examples include polyarylate (PAR), polysulfone (PSF), polyethersulfone (PES), polyphenylene sulfide (PPS), polyetheretherketone (PEEK), polyimide (PI), polyetherimide (PEI). , Fluororesin, liquid crystal polymer (LCP), and the like.

  Next, a method for assembling the tapered roller bearing will be described. First, the rollers 23 are accommodated in the pockets 24 d of the cage 24. Thereafter, the inner ring 21 is pushed into the inner circumference of the cage 24, and further the outer ring 22 is pushed in the axial direction and fitted to the outer circumference of each roller 23. The engaging part 36 of the retainer 24 can be engaged with the notch part 38 by being elastically deformed. At this time, there is a slight gap in the axial direction and the radial direction between the engaging portion 36 and the notch portion 38, so that the cage 24 can move slightly in the axial direction and the radial direction.

  Until the tapered roller bearing is assembled in the machine, the roller 23 tends to drop to the small end side by its own weight, and accordingly, the pressing force in the same direction acts on the retainer 24 as well. Along with this, the engaging portion 36 engages with the notch provided in the inner ring 21 from the large end side, so that further displacement of the retainer 24 to the small end side is restricted. In this case, since the displacement of the roller 23 toward the small end side is restricted by the inner diameter side 37 of the pocket 24d, it is possible to reliably prevent the roller 23 from falling off the inner ring 21.

  In the tapered roller bearing of the present invention, the raceway surface 25 of the inner ring 21 reaches the small diameter end from the flange portion 26, and the small diameter side flange portion of the inner ring that has been conventionally present is omitted. For this reason, this omission part and weight reduction can be achieved. In addition, the raceway surface is enlarged only in the small diameter side flange portion and the omitted portion which are omitted, whereby the axial center length of the tapered roller can be increased, the load capacity can be improved, and a longer life can be achieved. it can. Further, since the retainer 24 is provided with the engaging portion 36 that engages with the flange portion 26 of the inner ring 21, it is possible to prevent the tapered roller 23 from falling off to the small end side, and the inner ring 21, the tapered roller 23, the retainer 24, and the like. Can be handled as an assembly (assembly unit body), and the assemblability (productivity) of the entire bearing can be improved.

  Moreover, since the engaging portions 36 are arranged so as to be accommodated in the corresponding pockets 24d when viewed from the axial direction, the molding die is pulled out without being affected by the engaging portions 36 when the retainer 24 is formed. be able to. For this reason, the improvement of manufacturability can be aimed at, and this tapered roller bearing can be manufactured stably and reliably. Further, since the cage 24 is made of resin, no wear powder is generated due to wear, and there is no possibility that the wear powder may cause a decrease in lubricity, thereby extending the life.

  By engaging the engaging portion 36 with the notched portion 38 of the flange portion 26, the engagement of the engaging portion 36 toward the flange portion can be improved, and the inner ring 21 of the engaging portion 36 can be improved. Projection outward in the axial direction on the large-diameter side can be avoided, and downsizing can be achieved. Further, since the engaging portions 36 are arranged so as to be accommodated in the corresponding pockets 24d when viewed from the axial direction, the depth of the notch portions 38 with which the engaging portions 36 engage can be reduced, and the strength of the flange portion 26 is reduced. Can be prevented. For this reason, insufficient roller bearing strength due to the flange 26 can be avoided, and tapered rollers can be stably received.

  Since the resin cage does not require operations such as bottom expansion and caulking in the assembly of the bearing, it is easy to ensure the required dimensional accuracy. In addition, resin cages are lighter in weight, self-lubricating, and have a smaller coefficient of friction than steel plates. It is possible to suppress the occurrence of wear due to the contact of. Further, since the resin cage is light and has a small coefficient of friction, it is suitable for reducing torque loss and cage wear at the time of starting the bearing.

  As described above, the embodiment of the present invention has been described. However, the present invention is not limited to the above-described embodiment, and various modifications are possible. For example, the number of locking pieces 36a constituting the engaging portion 36 is as follows. The number is not limited to four, but can be increased or decreased. However, in order to stably prevent the tapered rollers 23 from falling, it is preferable to arrange three or more unevenly along the circumferential direction. Further, in the embodiment, the notch portion 38 is opened on the end surface 21a on the large diameter side of the inner ring 21, but without being opened on the end surface 21a, an annular shape formed on the outer diameter surface 26c of the flange portion 26. You may comprise by a ditch | groove.

  This tapered roller bearing can be used in various parts where a tapered roller bearing can be used conventionally. In particular, it is preferable to use it for an automobile differential or transmission because it can cope with an increase in engine torque and multi-stages.

It is sectional drawing of the tapered roller bearing which shows embodiment of this invention. It is a front view of the retainer of the tapered roller bearing. It is sectional drawing of the said conventional tapered roller bearing. It is a perspective view of the retainer of the conventional tapered roller bearing.

Explanation of symbols

21 Inner ring 22 Outer ring 23 Tapered roller 24d Pocket 24 Cage 26 Cage part 36 Engagement part 36a Locking piece 38 Notch part

Claims (2)

In 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 resin cage that holds the tapered rollers at a predetermined circumferential interval,
Providing a flange that protrudes toward the outer diameter side on the large-diameter side of the inner ring and that receives the large end surface of the tapered roller, forms a raceway surface that reaches the small-diameter end from this flange, and an inner diameter on the large-diameter side of the cage An engaging portion that protrudes in the direction and engages with the flange portion of the inner ring is provided , and the inner diameter end of the engaging portion is positioned on the outer diameter side of the outer diameter edge of the inner diameter side of the pocket, and A tapered roller bearing , wherein a width dimension is set smaller than a minimum width dimension of the pocket, and the engaging portion is disposed so as to be accommodated in a pocket at a corresponding position when viewed in the axial direction. 2. The tapered roller bearing according to claim 1, wherein a notch portion is provided on an outer diameter surface of the flange portion, and an engaging portion is locked to the notch portion.

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