JP6557045B2 - Tapered roller bearing manufacturing method - Google Patents

Description

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

  Tapered roller bearings are widely used as high load bearings for power transmission systems for automobiles and industrial machinery. 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. 6, 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 a tapered roller bearing usually encloses a solid lubricant material in a fluidized state before solidification directly into the bearing internal space of the actual bearing using an enclosing jig or the like, and heats the inside of the bearing. It is solidified by cooling and manufactured (see Patent Document 2).

  A tapered roller bearing in which a solid lubricant is encapsulated 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.

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

  FIG. 7 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 in Patent Document 2 described above. The inner ring 22, the outer ring 23, the plurality of tapered rollers 24, and the cage 25 are combined to form a tapered roller bearing (no solid lubricant), and two encapsulating molds are formed at both axial ends of the bearing. A jig 29 is arranged to seal the bearing internal space. In this state, the solid lubricant material 26 'is filled in the entire bearing internal space (including a part of the external space formed by the enclosing jig) between the inner and outer rings through the solid lubricant filling port 29a or 29b. Here, the outer ring 23 has chamfered portions 23b at both ends of the inner peripheral surface located on both sides of the raceway surface 23a. Therefore, when the solid lubricant material 26 ′ is filled, the material also enters between the chamfered portion 23 b and the enclosing jig 29, and this portion remains as a burr 26 b of the solid lubricant 26 after solidification. Of the 29a and 29b in the figure, the one not used as the filling port serves as an escape port for discharging the excess solid lubricant material 26 'to the outside of the enclosing jig during filling.

  Tapered roller bearings differ from ball bearings, cylindrical roller bearings, and the like in that it is necessary to separate the inner ring and the outer ring for handling. In the tapered roller bearing 21 obtained by the manufacturing method as described above, if the burr 26b exists in the chamfered portion 23b of the outer ring 23, it is impossible or difficult to separate the outer ring 23 from the inner ring side member including the solid lubricant 26. Become. Further, since the burr 26b is in sliding contact with the chamfered portion 23b of the outer ring 23, the contact area between the solid lubricant 26 and the outer ring 23 is increased, and there is a concern that heat and rotational torque during operation increase. In addition, the burr 26b may fall off during operation. For this reason, after the solid lubricant 26 is solidified, a burr 26b removal step may be required as a post-treatment.

  The present invention has been made to cope with such a problem, and in a tapered roller bearing filled with a solid lubricant, a burr that makes it difficult to separate an outer ring at the time of manufacture is not generated, and a work process is reduced. It aims at providing the manufacturing method of the tapered roller bearing which can aim at.

  A method for manufacturing a tapered roller bearing according to 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, the inner ring raceway surface, and the outer ring raceway surface. A tapered roller bearing comprising: a plurality of tapered rollers that roll between and a solid lubricant in a bearing internal space, wherein: (1) the inner ring, the tapered roller, and the cage; And a step of assembling an outer ring model that does not have chamfered portions at both ends of the inner peripheral surface and an enclosing jig to seal the bearing internal space, and (2) the entire sealed space. (3) a step of solidifying the filled material, (4) a step of removing the enclosing jig and the outer ring model, (5) ) The obtained inner ring, the tapered roller, the cage, A step of assembling the outer ring member composed of the solid lubricant and, and characterized in that it comprises a.

  The outer ring model is formed integrally with the enclosing jig as a part of the enclosing jig.

  The axial section of the raceway surface of the outer ring has a medium-high shape, and the axial section of the raceway surface of the outer ring model is a linear shape or a medium-low shape.

  The method of manufacturing a tapered roller bearing according to the present invention includes: (1) an inner ring, a tapered roller, and a cage in a combined state, an outer ring model that does not have chamfered portions at both ends of the inner peripheral surface, an enclosing jig, To seal the bearing internal space, (2) filling the whole sealed space with the material before solidifying the solid lubricant, and (3) solidifying the filled material. , (4) a step of removing the enclosing jig and the outer ring model, and (5) a step of assembling the outer ring to the obtained inner ring, tapered roller, cage, and member made of solid lubricant. No burrs are generated around the chamfered portions at both ends of the inner peripheral surface located on both sides of the raceway surface so that it becomes impossible or difficult to separate the outer ring from the inner ring side member containing the solid lubricant. This eliminates the need for a burr removal process and reduces work processes.

  Since the outer ring model is formed integrally with the enclosing jig as a part of the enclosing jig, it is not necessary to assemble the outer ring model in the step (1), and the number of parts of the manufacturing facility can be reduced. Further, the gap between the outer ring model and the enclosing jig can be eliminated, and the generation of the burr can be more completely prevented.

  The axial section of the raceway surface of the outer ring is a medium-high shape, and the axial section of the raceway surface of the outer ring model is a linear shape or a medium-low shape, so that the outer ring raceway surface and the raceway surface of the solid lubricant are opposed to each other. A gap can be formed between the surface to be cut. Therefore, while enjoying the excellent lubrication characteristics of the solid lubricant, 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.

It is a process flow figure of the manufacturing method of the tapered roller bearing of the present invention. It is a figure which shows the mode of an example of the manufacturing method of FIG. 1, and a finished product. It is a figure which shows the mode of the other example of the manufacturing method of FIG. 1, and a finished product. It is an axial sectional view showing an example of a tapered roller bearing of the present invention. FIG. 5 is a partially enlarged view of FIG. 4. It is an axial sectional view of a conventional tapered roller bearing. It is a figure which shows the mode of the conventional manufacturing method, and a finished product.

  A method for manufacturing a tapered roller bearing according to the present invention will be described with reference to FIGS. FIG. 1 is a process flow diagram of the manufacturing method, and FIG. 2 is a diagram showing an example of the manufacturing method shown in FIG. 1 and a finished product thereof. As shown in FIG. 1, the method of manufacturing a tapered roller bearing according to the present invention is as follows: (1) An inner ring, a tapered roller, and a cage are combined, and the outer ring does not have chamfered portions at both ends of the inner peripheral surface. A step of assembling the model and the sealing jig to seal the bearing internal space [preparation step], and (2) a step of filling the entire sealed space with the material before solid lubricant solidification [filling step]. And (3) a step of solidifying the filled material [solidification step], (4) a step of removing the enclosing jig and the outer ring model [release step], and (5) the obtained inner ring, tapered roller, A cage and a step [final step] of assembling the outer ring to a member made of a solid lubricant are provided.

(1) Preparatory process As shown in FIG. 2 (upper figure), as a preparatory process, it is set as the state which combined the inner ring 2, the tapered roller 4, and the cage | basket 5, and has a chamfering part of an inner peripheral surface both ends in this. The outer ring model 8 and the enclosing jig 9 are assembled to seal the bearing internal space. The size and combination position of each bearing member, outer ring model, and enclosing jig are appropriately adjusted according to the shape of the finished product. The outer ring model 8 has substantially the same shape as the outer ring 3 of the actual machine (the lower diagram in FIG. 2), and can be combined with other members in the same manner as the outer ring 3, and the solid lubricant surface formed by the model has an adverse effect during use. Does not affect. More specifically, the outer ring model 8 has the same dimensions as the outer ring 3 except that it does not have a chamfered portion corresponding to the chamfered portion 3b of the outer ring 3 of the actual machine and there is a slight difference in the raceway surface described later. . The shape of both ends of the inner peripheral surface of the outer ring model 8 is a shape obtained by extending the outer ring raceway surface of the outer ring model as it is because there is no chamfered portion. The enclosing jig 9 is a mold, encloses both axial ends of the bearing, and seals the bearing internal space between the inner and outer rings and the external space partially protruding from the both axial end portions. .

(2) Filling step and (3) Solidification step First, the solid lubricant used in the present invention will be described. 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 physical properties to exude, (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.

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 as a method of filling the bearing internal space with the solid lubricant (A). The normal temperature method is that a normal temperature solid lubricant molding encapsulating jig is placed in the interior space of a normal temperature tapered roller bearing (outer ring is an example of an outer ring) when filled with a normal temperature solid lubricant material before solid. The inside space of the bearing is sealed, and in this state, the material is heated in a temperature range above the gel point of the ultra-high molecular weight polyolefin (for example, about 150 to 200 ° C.) and below the dropping point, and then cooled to solidify the whole. It is a method to convert. In addition, the high temperature method can be used in a preheated tapered roller bearing (outer ring is an outer ring model) in the bearing internal space at a temperature range above the gel point of the ultra-high molecular weight polyolefin and below the dropping point at high temperature. This is a method in which a high-temperature solid lubricant molding enclosing jig is arranged to seal the bearing internal space and then cooled to solidify the whole when the heated product is filled at a high pressure. 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 and solidified inside the bearing.

  As shown in FIG. 2 (upper drawing), in the filling step, the solid lubricant material 6 ′ before solidification of the solid lubricant is filled into the entire space sealed in the preparation step from the filling port 9 a or 9 b. At this time, the excess solid lubricant material 6 'is discharged from the escape port 9a or 9b to the outside of the enclosing jig, and the entire space is filled with the solid lubricant material 6' densely. Here, the direction of the filling port is not limited. When 9a is used as the filling port, 9b is an escape port, and when 9b is used as the filling port, 9a is the escape port. As described above, in the case of the normal temperature method, the solid lubricant material 6 ′ at normal temperature is filled in a state where the bearing members and the enclosing jig 9 are not heated. 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. In the case of the high temperature method, the high temperature solid lubricant material 6 ′ is filled in a high temperature state where each bearing member is heated.

  In the solidification step, in the case of the room temperature method, the entire enclosing jig 9 filled with the solid lubricant material 6 ′ is fired and then cooled to solidify the material to obtain the solid lubricant 6 inside the bearing. In the case of the high temperature method, the solid lubricant material 6 ′ is cooled to solidify the material, and the solid lubricant 6 is formed inside the bearing.

  In the manufacturing method of the present invention, since the outer ring model 8 having no chamfered portions at both ends of the inner peripheral surface located on both sides of the outer ring raceway surface is used in the preparation step, a solid lubricant is applied to these ends in the filling step. It is possible to prevent burrs from being generated in the solidification process without entering the material. This eliminates the need for a subsequent deburring process and reduces the number of work processes.

(4) Release process and (5) Final process In the release process, the inner ring 2, the tapered roller 4, the cage 5, and the solid lubricant 6 are integrated by removing the sealing jig 9 and the outer ring model 8. Is obtained. As shown in FIG. 2 (below), as a final process, the outer ring 3 having the chamfered portions 3b is assembled to both ends of the inner circumferential surface located on both sides of the raceway surface 3a, and the tapered roller bearing 1 is completed. The tapered roller bearing 1 has a solid lubricant burr around the chamfered portion 3b of the outer ring 3 so that it is impossible or difficult to separate the outer ring 3 from the inner ring side member including the solid lubricant 6. Absent.

  Another example of the method for manufacturing the tapered roller bearing of the present invention will be described with reference to FIG. FIG. 3 is a diagram showing another example of the manufacturing method shown in FIG. 1 and a finished product thereof. As shown in FIG. 3 (upper drawing), in this manufacturing mode, (1) as a preparation step, the inner ring 2, the tapered roller 4, and the cage 5 are combined, and the chamfered portions at both ends of the inner peripheral surface are combined. An enclosure jig 9 having an outer ring model 8 portion that does not have an integral part is assembled to seal the bearing internal space. The details of the shape of the outer ring model 8 are the same as in the case of FIG. Also, (2) filling step, (3) solidification step, (4) release step (the enclosure jig 9 and the outer ring model 8 portion are integrally removed), and (5) the final step are the same as in FIG. It is. Since the outer ring model is formed integrally with the enclosing jig as a part of the enclosing jig, it is not necessary to separately assemble the outer ring model 8 in the preparation process, and the number of parts of the manufacturing facility can be reduced. Further, there is no gap between the outer ring model 8 and the enclosing jig 9, and the generation of burrs can be more completely prevented.

  An example of the tapered roller bearing obtained by the manufacturing method of the present invention will be described with reference to FIGS. 4 is an axial sectional view of the entire tapered roller bearing filled with the solid lubricant, and FIG. 5 is a partially enlarged view of FIG. As shown in FIG. 4, the tapered roller bearing 1 includes an inner ring 2 having a tapered raceway surface 2a on the outer peripheral surface, an outer ring 3 having a tapered raceway surface 3a on the inner peripheral surface, and a raceway surface 2a of the inner ring 2. And a plurality of tapered rollers 4 that roll between the raceway surface 3a of the outer ring 3 and a retainer 5 that holds the tapered rollers 4 in a pocket portion so as to be freely rollable at regular intervals in the circumferential direction. 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.

  As shown in FIG. 5, the tapered roller bearing 1 is filled with a solid lubricant 6 in substantially the entire bearing inner space between the inner and outer rings. Part of the tapered roller 4 (axially central portion) is exposed from the solid lubricant 6 and is in contact with the raceway surface 3 a of the outer ring 3 and the raceway surface 2 a of the inner ring 2. The method of filling the solid lubricant is according to the above manufacturing method. For this reason, the tapered roller bearing 1 does not have burrs around the chamfered portions 3 b at both ends of the inner peripheral surface located on both sides of the raceway surface 3 a of the outer ring 3. Also, the raceway surface 3a of the outer ring 3 is subjected to crowning, and the axial cross section of the raceway surface of the outer ring model at the time of manufacture is made linear, etc. Between the surface 6a facing the surface 3a, minute gaps 7 serving as non-contact portions on both surfaces can be formed at both ends in the axial direction. The gap 7 is a gap that is formed at least partly in the axial direction and is continuous in the circumferential direction.

  4 and 5, the raceway surface 3 a of the outer ring 3 is subjected to crowning so as to have a medium-high shape that forms 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. Further, in the outer ring example used to form the surface 6a of the solid lubricant 6 that faces the raceway surface 3a, the raceway surface has a straight (straight) shape with the same dimensions except that the crowning process is not performed. The interval of the gap 7 between the raceway surface 3a of the outer ring 3 and the surface 6a of the solid lubricant 6 facing the raceway surface 3a is a minute interval that is about the amount of crowning drop.

  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 applicable in the present invention is not particularly limited, and is formed at the end of the contact portion, a full crowning (single arc) formed over the entire region of the contact portion between the raceway surface and the rolling surface. Cut crowning (combination of a plurality of arcs and straight lines), logarithmic function crowning, etc. can be employed. Use a raceway with various crowning processes as an actual machine, and select an outer ring model or enclosing jig that does not have the process on the raceway surface and has a linear or medium-low cross section in the axial direction of the raceway surface. By adopting, the shape of the gap can be adjusted. The minute gap 7 can reduce the contact area between the solid lubricant and each raceway surface, and can reduce heat generation and rotational torque during operation.

  In the form (full pack) in which the solid lubricant 6 is filled in substantially the entire bearing internal space, the contact area tends to increase, but this can be prevented by forming the gap. Further, since the solid lubricant 6 expands due to heating or the like during solidification, the contact with the raceway surface is usually close and there is a risk of an increase in rotational torque. However, by forming the gap, Can be prevented.

  In the form shown in FIG. 4, the large collar 2 b is integrally formed at the large-diameter end of the inner ring 2 and the small collar 2 c is integrally formed at the small-diameter end so that the tapered roller 4 and the cage 5 do not fall off from the inner ring 2. I have to. Further, by providing a structure in which the solid lubricant 6 is engaged with the inner ring 2, the small flange 2c can be omitted, and the axial length of the tapered roller 4 can be extended to increase the load capacity. For example, by forming an engagement groove inward in the radial direction on the outer side (left side in the figure) of the large flange 2b, it is possible to engage the groove on the solid lubricant 4 side when filling and curing the solid lubricant. Are formed, and by these engagement structures, a small scissors can be omitted. In addition, it is good also as a form which forms a holder | retainer with a solid lubricant.

  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 method of manufacturing a tapered roller bearing according to the present invention is a tapered roller bearing filled with a solid lubricant, and does not generate burrs that make it difficult to separate the outer ring at the time of manufacturing. Can be suitably used as a method for producing various tapered roller bearings (filled with a solid lubricant).

DESCRIPTION OF SYMBOLS 1 Tapered roller bearing 2 Inner ring 3 Outer ring 4 Tapered roller 5 Cage 6 Solid lubricant 7 Crevice 8 Outer ring model 9 Enclosing jig

Claims (3)

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; A method of manufacturing a tapered roller bearing comprising a cage that holds the plurality of tapered rollers , the bearing internal space being filled with a solid lubricant,
The inner ring, the tapered roller, and the cage are combined, and an outer ring model that does not have chamfered portions at both ends of the inner peripheral surface and a sealing jig are assembled to seal the bearing inner space. When,
Filling the entire sealed space with the material before solidifying the solid lubricant;
Solidifying the filled material;
Removing the enclosing jig and the outer ring model,
And a step of assembling the outer ring to the member made of the inner ring, the tapered roller, the cage, and the solid lubricant obtained.   2. The method of manufacturing a tapered roller bearing according to claim 1, wherein the outer ring model is formed integrally with the enclosing jig as a part of the enclosing jig.   The cone according to claim 1 or 2, wherein an axial section of the raceway surface of the outer ring has a medium-high shape, and an axial section of the raceway surface of the outer ring model has a linear shape or a medium-low shape. A method of manufacturing a roller bearing.

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