JP2016180477A - Conical roller bearing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a conical roller bearing filled with a solid lubricant, which can reduce heating and rotational torque during operation.SOLUTION: A conical roller bearing 1 includes: an inner ring 2 having a tapered inner ring raceway surface 2a on its outer peripheral surface; an outer ring 3 having a tapered outer ring raceway surface 3a on its inner peripheral surface; a plurality of conical rollers 4 rolling between the inner ring raceway surface 2a and the outer ring raceway surface 3a; and a holder 5 rollably holding the conical rollers 4 in a circumferential direction with a predetermined interval. A bearing internal space is partially filled with a solid lubricant 6. The solid lubricant 6 is held by the holder 5, and brought into non-contact with at least one raceway surface selected from the inner ring raceway surface 2a and the outer ring raceway surface 3a.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a tapered roller bearing using a tapered roller as a rolling element, and more particularly to a tapered roller bearing in which a solid lubricant is filled in a bearing internal space.

  Tapered roller bearings are widely used as bearings for high loads such as automobiles and industrial power transmission systems. Tapered roller bearings are used with a preload to improve rigidity and rotational accuracy. The structure of a conventional general tapered roller bearing will be described with reference to FIG. As shown in FIG. 3, the tapered roller bearing 11 includes an inner ring 12 having a tapered raceway surface 12 a on the outer peripheral surface, an outer ring 13 having a tapered raceway surface 13 a on the inner peripheral surface, and a raceway surface 12 a of the inner ring 12. And a plurality of tapered rollers 14 that roll between the raceway surface 13a of the outer ring 13 and a retainer 15 that holds each tapered roller 14 in a pocket portion so that it can roll freely. The cage 15 is formed by connecting a large-diameter ring portion and a small-diameter ring portion with a plurality of column portions, and houses tapered rollers 14 in pocket portions between the column portions. A large collar 12b is integrally formed at the large diameter end of the inner ring 12, and a small collar 12c is integrally formed at the small diameter end. The inner ring in the tapered roller bearing has a tapered raceway surface, so that it has a small diameter side and a large diameter side when viewed in the axial direction, and the “small collar” is a collar provided at the end of the small diameter side. The “cradle” is a scissor provided at the end on the large diameter side. When a load is applied, the tapered roller 14 is pressed to the large diameter side, and this load is received by the large hook 12b. Moreover, the tapered roller 14c prevents the tapered roller 14 from dropping to the small diameter side before the bearing is incorporated into various devices.

  With the miniaturization and high performance of the equipment in which the tapered rollers are used, the usage environment of the tapered roller bearings is becoming severer year by year. For example, an increase in load capacity and a longer life are required. Conventionally, in order to increase the load capacity, it has been proposed that the length of the tapered roller is extended by eliminating the inner ring and the cage of the tapered roller bearing is formed of solid grease (solid lubricant). (See Patent Document 1). In Patent Document 1, instead of a normal cage, a conical cylindrical solid grease cage that is filled between tapered rollers to hold each tapered roller and engages the inner ring in the axial direction is used. ing. In addition, such tapered roller bearings are usually manufactured by filling a solid lubricant material in a fluidized state before solidification into a bearing internal space using an enclosing jig or the like, and solidifying the inside of the bearing by heating or cooling. (See Patent Document 2).

  A tapered roller bearing filled with a solid lubricant can be expected to have a good lubricating action over a long period of time because the lubricating oil is gradually released from the solid lubricant. Further, since the lubricant can be present near the rolling surface, the lubricating oil is more easily supplied to the rolling surface as compared with mere grease lubrication. Furthermore, it also serves as a seal against entry of dust and moisture from the outside.

  In general, in order to extend the rolling fatigue life of the tapered roller bearing, it is necessary to reduce the contact surface pressure between the raceway surface of the inner and outer rings and the rolling surface of the tapered roller. In order to reduce the contact surface pressure under a constant load, it is important to make the axial surface pressure distribution uniform. As a method for this, the inner ring or outer ring raceway surface of the tapered roller bearing or the rolling surface of the tapered roller is used. Is known to be processed into a crowning shape. The crowning shape is a shape in which the raceway surface has a slight bulge. The crowning includes full crowning formed over the entire region in the generatrix of the contact portion between the raceway surface and the rolling surface, and cut crowning formed at the end of the contact portion.

JP 2008-157111 A JP-A-9-94893

  FIG. 4 shows an example in which a tapered roller bearing (full pack) in which a solid lubricant as in Patent Document 1 is filled in the bearing internal space is manufactured by the manufacturing method as described in Patent Document 2 above. When the material of the solid lubricant 26 is poured into the tapered roller bearing 21, the material is filled in substantially the entire interior space of the bearing. After solidification, the raceway surfaces of the inner ring 22 and the outer ring 23 and the surface of the solid lubricant 26 that is a contact surface facing the raceway surfaces are in close contact with each other. In the example shown in FIG. 4, since the raceway surface 23a of the outer ring 23 has a crowning shape, the solid lubricant 26 is also filled in the gap 27 formed by the raceway surface 23a having the crowning shape and the rolling surface 24a of the tapered roller. Is done. For this reason, in the solid lubricant 26, the surface 26 a that faces and contacts the raceway surface 23 a of the outer ring 23 is a portion where the tapered roller 24 is exposed from the solid lubricant 26 and is in contact with the raceway surface 23 a (a substantially central portion in the axial direction). Except for), the whole is in sliding contact and slipping occurs. For this reason, the contact area between the solid lubricant and each raceway surface increases, and heat and rotational torque during operation increase.

  The present invention has been made to cope with such problems, and an object of the present invention is to provide a tapered roller bearing that can reduce heat generation and rotational torque during operation in a tapered roller bearing filled with a solid lubricant.

 The tapered roller bearing of the present invention includes an inner ring having a tapered inner ring raceway surface on an outer peripheral surface, an outer ring having a tapered outer ring raceway surface on an inner peripheral surface, and the inner ring raceway surface and the outer ring raceway surface. A tapered roller bearing comprising a plurality of tapered rollers that roll and a cage that holds the tapered rollers so as to be freely rollable at a constant interval in the circumferential direction. The tapered roller bearing is partially in the interior space of the bearing. Solid lubricant is filled, and the solid lubricant is held in the cage and is not in contact with at least one raceway surface selected from the inner ring raceway surface and the outer ring raceway surface.

  The cage includes a large-diameter ring portion and a small-diameter ring portion connected by a plurality of pillars, and a bearing inner diameter at an end of at least one ring portion selected from the large-diameter ring portion and the small-diameter ring portion. And the solid lubricant is held on the bearing inner diameter side of the cage while being engaged with the flange.

  The flange has a hole penetrating in the axial direction, and the solid lubricant is engaged with the flange through the hole.

  The solid lubricant is formed by filling a solid lubricant forming portion in the bearing internal space with a material before solidifying the solid lubricant and then solidifying the solid lubricant.

  The tapered roller bearing of the present invention rolls between an inner ring having a tapered inner ring raceway surface on an outer peripheral surface, an outer ring having a tapered outer ring raceway surface on an inner peripheral surface, and an inner ring raceway surface and an outer ring raceway surface. A plurality of tapered rollers, and a cage that holds the tapered rollers so as to roll freely at a constant interval in the circumferential direction. The solid lubricant is partially filled in a bearing internal space. Is held by the cage and is not in contact with at least one of the raceway surfaces. Compared with the case where the entire interior space (full pack) of the bearing is filled while enjoying the excellent lubrication characteristics of the solid lubricant. Thus, the contact area between the solid lubricant and each raceway surface can be reduced, and heat generation and rotational torque during operation can be reduced. As a result, the allowable rotational speed of the tapered roller bearing filled with the solid lubricant can be improved.

  The cage is formed by connecting a large-diameter ring portion and a small-diameter ring portion with a plurality of pillars, and at the end of at least one ring portion selected from the large-diameter ring portion and the small-diameter ring portion on the bearing inner diameter side. Since it has a flange portion that extends and the solid lubricant is held on the bearing inner diameter side of the cage while engaging with the flange portion, it is possible to prevent the solid lubricant from falling off and shifting during operation. Furthermore, it has the hole penetrated to an axial direction in a collar part, forms a solid lubricant through this hole, and it can fix to a holder | retainer more firmly by engaging with a collar part.

  As described above, in the tapered roller bearing of the present invention, the solid lubricant is partially filled in the inner space of the bearing, and the above-described flange portion or the like is formed in the cage as necessary, and the solid lubricant is retained in the cage. To hold. For this reason, even in the form of solidifying after filling the solid lubricant forming site with the material before solidification, there is an excess space in the bearing internal space, and an increase in rotational torque due to the expansion of the solid lubricant, etc. Can be prevented.

It is the axial direction partial sectional view and radial direction partial sectional view which show an example of the tapered roller bearing of this invention. It is an axial direction partial sectional view and cage end view showing other examples of a tapered roller bearing of the present invention. It is an axial sectional view of a conventional tapered roller bearing. FIG. 4 is a partially enlarged view when the solid lubricant is filled in the bearing of FIG. 3.

  An example of the tapered roller bearing of the present invention will be described with reference to FIG. 1A is a partial sectional view in the axial direction of a tapered roller bearing filled with a solid lubricant, and FIG. 1B is cut along a plane perpendicular to the central axis of the tapered roller in FIG. FIG. 3 is a partial cross-sectional view (only tapered rollers, cages, solid lubricants) in a substantially radial direction. As shown in FIG. 1 (a), a tapered roller bearing 1 of this form includes an inner ring 2 having a tapered raceway surface 2a on an outer peripheral surface, an outer ring 3 having a tapered raceway surface 3a on an inner peripheral surface, A plurality of tapered rollers 4 that roll between the raceway surface 2a of the inner ring 2 and the raceway surface 3a of the outer ring 3, and a cage 5 that holds the tapered rollers 4 in a pocket portion so as to be freely rollable at regular intervals in the circumferential direction. Prepare. The cage 5 is formed by connecting a large-diameter ring portion 5a and a small-diameter ring portion 5b with a plurality of column portions 5c, and houses the tapered rollers 4 in pocket portions between the column portions. Each raceway surface has a tapered shape in which the diameter constituting the raceway surface increases and decreases along the axial direction. The taper angle is not particularly limited, but is usually about 15 ° to 60 ° with respect to the axial direction. Further, the large collar 2b is integrally formed at the large diameter end of the inner ring 2, and the small collar 2c is integrally formed at the small diameter end.

  In a conventional ball bearing such as a deep groove ball bearing, a method of spot-packing a solid lubricant is known. In the bearing, for example, a corrugated retainer (a ball and a ball and a ball and a ball) are combined with two metal plates. The portion located between the inner and outer rings is filled for each mating portion in such an amount as to contact the raceway surface of the inner and outer rings. However, in the tapered roller bearing, when the contact area between the solid lubricant and each raceway surface is increased, the rotational torque is likely to increase as compared with the case of the deep groove ball bearing described above. In particular, even in the case of a spot pack, if the solid lubricant enters the gap between the chamfered portion of the inner peripheral surface end portion of the outer ring and the outer ring due to the crowning shape and the tapered roller rolling surface, the rotational torque may increase significantly. .

  In contrast, as shown in FIGS. 1A and 1B, the tapered roller bearing 1 of the present invention is partially filled with a solid lubricant 6 (spot pack) in the bearing internal space. It is characterized in that the solid lubricant 6 is held in the cage 5 and is not in contact with at least one raceway surface selected from the raceway surface 2 a of the inner ring 2 and the raceway surface 3 a of the outer ring 3. In the embodiment shown in FIG. 1A, no contact is made with any of the raceway surfaces. As described above, the tapered roller bearing of this embodiment is liable to be adversely affected when in contact with the outer ring raceway surface. Therefore, it is preferable that at least the raceway surface 3a of the outer ring 3 is not in contact. Even if the solid lubricant does not directly contact the raceway surface, it is in contact with the rolling surface of the tapered roller, and the lubricating oil that has oozed out of the solid lubricant is sufficient for the raceway surface and the rolling surface. Supplied.

  The cage 5 shown in FIG. 1 (a) has flanges 5d extending to the bearing inner diameter side at the ends of the large-diameter ring portion 5a and the small-diameter ring portion 5b. The solid lubricant 6 is held by the cage 5 with its axial ends engaged with the flange 5d. With this structure, it is possible to prevent the solid lubricant 6 from falling off or misaligned during operation. Further, as shown in FIG. 1 (b), the solid lubricant 6 is held on the inner side (bearing inner diameter side) of the column portion 5c, so that it is prevented from dropping to the outer diameter side due to centrifugal force during operation. it can.

  When the cage is made of metal, the flange portion 5d can be easily formed by bending the end portion of each ring portion by pressing. In the embodiment shown in FIG. 1A, the end portion is not only simply bent to the bearing inner diameter side, but the tip portion is further bent inward in the axial direction. Thereby, it can hold | maintain so that the solid lubricant 6 may be held in the holder | retainer 5, and the more stable holding | maintenance is attained. In addition, when the cage is a heat resistant resin (which can sufficiently withstand the firing temperature of the solid lubricant), the flange portion can be integrally formed at the time of molding by injection molding or the like.

  Further, the spot pack of the solid lubricant 6 is partially formed in the space between the tapered rollers divided in the circumferential direction of the bearing, and the solid lubricant between these tapered rollers is outside the both ends in the axial direction of the tapered rollers. May be formed in a shape connected in the circumferential direction.

  Another example of the tapered roller bearing of the present invention will be described with reference to FIG. FIG. 2A is a partial sectional view in the axial direction of a tapered roller bearing filled with a solid lubricant, and FIG. 2B is an end view on one axial side of the cage alone. As shown in FIG. 2A, the tapered roller bearing 1 of this embodiment is the same as that shown in FIG. 1A except that the configuration of the cage 5 and the solid lubricant 6 held by the cage 5 is different. is there. The tapered roller bearing 1 is partially filled with a solid lubricant 6 in a bearing inner space (spot pack). The solid lubricant 6 is held by the cage 5 and is not in contact with any of the raceway surfaces 2 a of the inner ring 2 and the raceway surface 3 a of the outer ring 3.

  Here, the cage 5 shown in FIG. 2 (a) has flange portions 5d extending to the bearing inner diameter side at the ends of the large diameter ring portion 5a and the small diameter ring portion 5b. Further, the flange 5d has a hole 5e penetrating in the axial direction, and the solid lubricant 6 is engaged with the flange 5d through the hole 5e. As shown in FIG. 2B, a plurality of holes 5e are formed at equal intervals in the circumferential direction of the flange 5d. When the solid lubricant material before solidification is spot-filled around the cage 5, the material also enters the hole 5e portion of the flange portion 5d. Then, it becomes an anchor structure which does not come out physically by solidifying. With this structure, the solid lubricant 6 can be firmly fixed to the cage 5. The hole 5e can be appropriately formed by drilling, cutting, press punching or the like according to the cage material.

  In the form shown in FIGS. 1 and 2, the raceway surface 3a of the outer ring 3 is subjected to crowning, and has a medium-high shape that becomes a very slight bulge when viewed in the axial cross section. The amount of radius reduction (drop amount) at both ends of the outer ring raceway surface caused by this crowning is about several tens of μm. When the raceway surfaces of the inner and outer rings (race rings) and the rolling surfaces of the tapered rollers come into contact with each other, stress concentration may occur at the end of the contact and the contact surface pressure may be excessive (edge stress). On the other hand, edge stress can be avoided and rolling fatigue life can be extended by applying crowning to either or both of the raceway surface of the raceway and the rolling surface of the tapered roller that contact each other. it can. The type of crowning applied in the present invention is not particularly limited, and is formed on the full crowning (single arc) formed over the entire region of the contact portion between the raceway surface and the rolling surface at the end portion of the contact portion. Cut crowning (combination of multiple arcs and straight lines), logarithmic function crowning, etc. can be employed.

  The type of solid lubricant used in the present invention is not particularly limited. For example, (A) an ultra-high molecular weight polyolefin is mixed in a lubricating oil or grease, and a liquid lubricating component is held between the resin molecules, and gradually. Solid lubricant with exuding physical properties, (B) obtained by reacting polyol and diisocyanate in the presence of a lubricating component, or a urethane prepolymer having an isocyanate group in the molecule and a curing agent as a lubricating component Examples thereof include a polyurethane-based solid lubricant obtained by reacting in the presence, a foamed (C) (B), and the like. Among these, (A) which is excellent in lubrication characteristics is preferable. Moreover, since (A) is excellent in rigidity, it can prevent deformation or the like during use of the tapered roller bearing. In addition, since these solid lubricants expand due to heating during solidification, etc., the contact with the raceway surface is usually close and there is a risk of increase in rotational torque. This problem can be dealt with because the inner space of the bearing is partially filled (around the cage) with no contact with them.

The above (A) will be described. The ultra-high molecular weight polyolefin powder used for this solid lubricant may be a powder composed of polyethylene, polypropylene, polybutene or a copolymer thereof, or a mixed powder obtained by blending individual powders. The average molecular weight measured is 1 × 10 ^{6 to} 5 × 10 ⁶ . A polyolefin having such a molecular weight range is superior to a low molecular weight polyolefin in rigidity and oil retention. Examples of the lubricating oil (base oil) include mineral oil, synthetic hydrocarbon oil, diester oil, polyol ester oil, alkyl diphenyl ether oil, silicone oil, and fluorine oil. Examples of the grease include grease obtained by increasing the above base oil with soap (metal soap, composite metal soap, etc.) or non-soap (urea compound, fluororesin, etc.). As a preferable blending ratio of the grease and the ultrahigh molecular weight polyolefin powder, the grease is 70 to 90% by weight, and the ultrahigh molecular weight polyolefin powder is 30 to 10% by weight.

  The solid lubricant may be blended with a solid wax for the purpose of suppressing oil seepage or preventing leakage of the lubricant from the bearing during firing. Examples of the solid wax include vegetable waxes such as carnauba wax and candelina wax, animal waxes such as beeswax and insect white wax, and petroleum waxes such as paraffin wax. The solid wax may be a blend such as a low molecular polyolefin containing the solid wax.

  There are a normal temperature method and a high temperature method for filling the formation site in the bearing internal space of the solid lubricant (A). The room temperature method is to fill the interior space of a tapered roller bearing at room temperature with a solid lubricant material at room temperature before solidification, together with an enclosing jig, if necessary, with a spot pack. In this method, the material is heated in a temperature range above the gel point of the polyolefin (for example, about 150 to 200 ° C.) and below the dropping point, and then cooled to solidify the whole. A mixture of grease and ultra-high molecular weight polyolefin powder has appropriate fluidity even at room temperature, and can be filled at room temperature. The filling of the necessary part may be carried out using an automatic filling machine or manually. Further, the high temperature method is a method in which a solid lubricant material (heated in a temperature range higher than the gelation point of the ultra-high molecular weight polyolefin and lower than the dropping point) is added to the bearing internal space of the preheated tapered roller bearing at a high temperature. This is a method in which an enclosing jig is used in combination as necessary and filled with a spot pack and then cooled to solidify the whole. As the enclosing jig, a jig that can regulate the outflow of material from the range of the shape at the time of filling is used in accordance with the shape of a desired formation site in the bearing internal space. In addition, for the solid lubricants (B) and (C), a similar filling method can be adopted except for temperature conditions. Both methods are the same in that the solid lubricant material before solidification is filled in a necessary portion and solidified in the bearing.

  In the form shown in FIG. 2 (a), in addition to filling the entire solid lubricant 6 at once, a method of filling the peripheral portion of the flange portion 5d and the inner portion of the column portion 5c in two stages is adopted. May be.

  As mentioned above, although an example of embodiment of this invention was demonstrated based on each figure, the tapered roller bearing of this invention is not limited to these.

  The tapered roller bearing of the present invention is a tapered roller bearing filled with a solid lubricant, and has excellent lubrication characteristics, and can reduce heat generation and rotational torque during operation, so that it can be used as various tapered roller bearings used in automobiles and industrial applications. It can be suitably used.

DESCRIPTION OF SYMBOLS 1 Tapered roller bearing 2 Inner ring 3 Outer ring 4 Tapered roller 5 Cage 6 Solid lubricant

Claims (4)

An inner ring having a tapered inner ring raceway surface on the outer peripheral surface, an outer ring having a tapered outer ring raceway surface on the inner peripheral surface, and a plurality of tapered rollers rolling between the inner ring raceway surface and the outer ring raceway surface; In the tapered roller bearing comprising a retainer that holds the tapered roller so as to roll freely at a constant interval in the circumferential direction,
The tapered roller bearing is partially filled with a solid lubricant in the interior space of the bearing,
A tapered roller bearing, wherein the solid lubricant is held by the cage and is not in contact with at least one raceway surface selected from the inner ring raceway surface and the outer ring raceway surface.   The cage is formed by connecting a large-diameter ring portion and a small-diameter ring portion with a plurality of pillars, and has a bearing inner diameter at an end of at least one ring portion selected from the large-diameter ring portion and the small-diameter ring portion. The tapered roller bearing according to claim 1, further comprising a flange extending toward the side, wherein the solid lubricant is held on a bearing inner diameter side of the cage while being engaged with the flange.   The tapered roller bearing according to claim 2, wherein the flange has a hole penetrating in the axial direction, and the solid lubricant is engaged with the flange through the hole.   3. The solid lubricant is formed by filling a solid lubricant forming site in the bearing internal space with a material before solidifying the solid lubricant and then solidifying the solid lubricant. A tapered roller bearing according to claim 3.

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