JP6639844B2 - Bearing rings and thrust needle bearings - Google Patents

Description

  The present invention relates to a bearing ring of a thrust needle bearing and a thrust needle bearing provided with the bearing ring.

  Conventionally, a raceway of a thrust needle bearing has a raceway surface and a surface opposite to the raceway surface inclined with respect to the axial center of the rotating shaft. When the thrust load applied to the thrust needle bearing is large, the inclination of the bearing ring is corrected, and the straight portion of the needle roller becomes a rolling surface. On the other hand, when the thrust load applied to the thrust needle bearing is small (for example, 70N), the inclination of the bearing ring is not corrected, and the crowning portion of the needle roller becomes the rolling surface. The crowning portion has a larger roundness than the straight portion. Therefore, when the crowning portion is a rolling surface, compared to when the straight portion is a rolling surface, the vibrations of the needle rollers and the bearing ring are increased, and further, the vibration is transmitted to a rotating shaft and the like. Noise due to the vibration increases.

  As technologies for improving the quietness of thrust needle bearings, technologies such as placing a vibration insulator between the thrust needle bearing and its supporting structure, and a crowning part by super-finishing at least near the axial end of the needle are used. A technique for providing the same is known (for example, see (for example, JP-A-2012-0979898 and JP-A-2012-215255)).

JP 2012-0979898 A JP 2012-215255 A

  However, in each case, there is a problem that the manufacturing cost is high. The present invention has been made to solve the above problems. A main object of the present invention is to provide a thrust needle bearing having high quietness and low manufacturing cost as compared with the thrust needle bearing.

  A bearing ring according to the present invention is a bearing ring of a thrust needle bearing, and includes a raceway surface and a back surface located on a side opposite to the raceway surface. The raceway surface and the back surface each include an inclined surface with respect to the axial direction of the thrust needle bearing. Further, the back surface includes a plurality of protrusions protruding in the axial direction on the inclined surface. The plurality of protrusions are arranged at an interval along the circumferential direction of the race.

  According to the present invention, it is possible to provide a thrust needle bearing having high silence and having a lower manufacturing cost than the thrust needle bearing.

FIG. 2 is a front view for explaining the bearing ring according to Embodiment 1. FIG. 2 is a sectional view as viewed from an arrow II-II shown in FIG. 1. FIG. 2 is a cross-sectional view for explaining a thrust needle bearing including the bearing ring according to Embodiment 1. FIG. 4 is a diagram for explaining an average phase angle. 4 is a flowchart illustrating a method for manufacturing a bearing ring according to Embodiment 1. 6 is a flowchart showing a modification of the method for manufacturing a bearing ring according to Embodiment 1. FIG. 5 is a front view for explaining a modification of the bearing ring according to Embodiment 1. FIG. 8 is a cross-sectional view as viewed from arrows VIII-VIII shown in FIG. 7. It is sectional drawing for demonstrating the thrust needle bearing provided with the bearing ring shown in FIG. FIG. 9 is a front view for explaining a bearing ring according to a second embodiment. It is sectional drawing seen from arrow XI-XI shown in FIG. FIG. 10 is a cross-sectional view for explaining a thrust needle bearing including a bearing ring according to Embodiment 2. 9 is a flowchart showing a method for manufacturing a bearing ring according to Embodiment 2. FIG. 13 is a cross-sectional view for explaining a modification of the bearing ring according to Embodiment 2. FIG. 9 is a cross-sectional view for explaining a thrust needle bearing of Sample 6. FIG. 7 is a cross-sectional view for explaining a thrust needle bearing of Sample 7. FIG. 9 is a diagram showing an evaluation result of a contact state between a bearing ring and a bearing support member when a thrust load of 70 N is applied to a thrust needle bearing of Sample 2. FIG. 14 is a diagram showing an evaluation result of a contact state between a bearing ring and a bearing support member when a thrust load of 70 N is applied to a thrust needle bearing of Sample 5. FIG. 10 is a diagram showing an evaluation result of a contact state between a bearing ring and a bearing support member when a thrust load of 70 N is applied to a thrust needle bearing of Sample 6. FIG. 14 is a diagram illustrating an evaluation result of a contact state between a bearing ring and a bearing support member when a thrust load of 70 N is applied to a thrust needle bearing of Sample 7. It is a graph which shows the acoustic measurement result of the thrust needle bearing of samples 1-10. FIG. 5 is a cross-sectional view showing a modification of the bearing ring according to Embodiment 1. FIG. 14 is a cross-sectional view showing a modification of the bearing ring according to Embodiment 2.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following drawings, the same or corresponding portions have the same reference characters allotted, and description thereof will not be repeated.

(Embodiment 1)
The race 10 according to the first embodiment will be described with reference to FIGS. The bearing ring 10 is a bearing ring of a thrust needle bearing 20 (see FIG. 3). The bearing ring 10 is connected to one end 1A in the axial direction on the side connected to the fixed shaft 32 (see FIG. 3) in the thrust needle bearing 20, and to the rotating shaft 31 (see FIG. 3) as a bearing support member in the thrust needle bearing 20. And the other end 1B on the connected side. The bearing ring 10 includes a main body 1 having a configuration similar to that of a conventional bearing ring, and a plurality of shims (convex portions) 4 fixed to the main body 1 and constituting the other end 1B. The main body 1 (the orbital ring 10) includes a first portion 2 extending in a direction intersecting with the axial direction, and a second portion 3 extending in the axial direction and connected to the first portion 2. Have. The first portion 2 includes a raceway surface 5 and a back surface 6 located on the opposite side of the raceway surface 5.

  As shown in FIGS. 2 and 3, the raceway surface 5 and the back surface 6 are each configured as an inclined surface with respect to the axial direction of the thrust needle bearing 20. The inner peripheral end of the back surface 6 is provided on the one end 1A side of the bearing ring 10, and the outer peripheral end of the back surface 6 is provided on the other end 1B side of the bearing ring 10. The axial distance from the inner peripheral end to the outer peripheral end of the back surface 6 (hereinafter, referred to as a taper amount) is 10 μm or more.

  Hereinafter, in a state where the inner peripheral end of the back surface 6 is provided on the one end 1A side of the race 10 and the outer peripheral end of the back surface 6 is provided on the other end 1B side of the race 10 The amount of taper is plus. On the other hand, in the state where the inner peripheral end of the back surface 6 is provided on the other end 1B side of the bearing ring 10 and the outer peripheral end of the back surface 6 is provided on the one end 1A side of the bearing ring 10, The taper amount is set to minus. The taper amount of the bearing ring 10 is, for example, ± 50 μm or less.

  The plurality of shims 4 project in the axial direction on the inclined surface of the back surface 6. The plurality of shims 4 are arranged at intervals along the circumferential direction of the bearing ring 10. The center of a circle contacting the inner diameter side of the plurality of shims 4 overlaps with the center point of the bearing ring 10. The plurality of shims 4 are configured separately from the bearing ring 10 (the main body 1). The plurality of shims 4 are fixed to the back surface 6 of the bearing ring 10 by, for example, bonding or welding. The plurality of shims 4 are provided, for example, four in the circumferential direction. The plurality of shims 4 are provided at equal intervals in the circumferential direction, for example. The plurality of shims 4 are preferably provided on the outer peripheral side of the bearing ring 10, and more preferably provided along the outer periphery of the bearing ring 10. The inner peripheral ends of the plurality of shims 4 are located, for example, between the outer peripheral end of the rear surface 6 and the inner peripheral end of the rear surface 6. That is, the plurality of shims 4 are provided on a part of the back surface 6 in the circumferential direction and the radial direction.

  The planar shape of the plurality of shims 4 when the race 10 is viewed in a plan view from the axial direction is arbitrary as long as a portion located on the outer diameter side of the shim 4 is provided along the outer periphery of the race 10. Any shape is acceptable. Portions of the plurality of shims 4 located on the outer diameter side are provided in an arc shape. The thickness of the plurality of shims 4 in the direction perpendicular to the back surface 6 can be accommodated in the installation space, and the bearing ring 10 and the bearing 10 are bent by elastic deformation when a thrust load is applied to the thrust needle bearing 20. Any thickness can be used as long as contact with the support member (rotary shaft 31) can be suppressed. The thickness of the plurality of shims 4 in the direction perpendicular to the back surface 6 is preferably equal to or less than the thickness of the bearing ring 10. For example, when the thickness of the bearing ring 10 is 0.8 mm, the thickness of the shim 4 is 0.01 mm.

  The material constituting the plurality of shims 4 has high durability even when a large thrust load is applied to the thrust needle bearing 20, and is elastically deformable when a relatively small thrust load (for example, 70N) is applied. Any material may be used, for example, at least one selected from the group consisting of a metal material, a resin material, and a ceramic material. Specifically, the material constituting the plurality of shims 4 may be at least one selected from a metal material group consisting of an iron-based material, a copper alloy, and an aluminum alloy. The materials constituting the plurality of shims 4 are a thermoplastic resin group consisting of polyimide, polyamide imide, polyether ether ketone, polyphenylene sulfide, polyamide, and polyethylene terephthalate, and a thermosetting resin consisting of phenol, unsaturated polyester, and epoxy. And at least one selected from the group of conductive resins. In addition, the material constituting the plurality of shims 4 includes at least one selected from the thermoplastic resin group and the thermosetting resin group, and at least one selected from the group of reinforcing materials such as glass fiber and carbon fiber. It may be blended. Further, the material forming the plurality of shims 4 may be at least one selected from a ceramic material group such as silicon nitride and silicon oxide.

  In the plurality of shims 4, the total length along the circumferential direction of the shim 4 on the inner diameter (inner circumference) side in the radial direction is 10% of the circumference of a circle in contact with the inner diameter side of the plurality of shims 4. % Or more and less than 50% (hereinafter, the ratio is referred to as a contact length ratio). Here, the length along the circumferential direction of the shim 4 on the inner diameter side is, for example, the shortest distance between both ends in the circumferential direction on the inner diameter side of the shim 4 in FIG. In other words, when considering a circle that is in contact with the inner diameter (inner circumference) side of the shim 4 about the center point O of the raceway ring 10 in the radial direction, for example, the contact point between the circle and the shim 4 is considered. This is the distance between the two ends located on the tangent to the passing circle.

  Referring to FIG. 4, on a plane perpendicular to the thrust direction, the average angle between the center point O of the race 10 in the radial direction and the circumferential ends of the plurality of shims 4 on the inner diameter side is 15 degrees. Not less than 30 degrees. Here, the average angle is an average value obtained by dividing the total value of the phase angles θ1, θ2, θ3, and θ4 between the center point O and the circumferential ends of each shim 4 on the inner diameter side by the number of shims 4. (Hereinafter, referred to as an average phase angle). It is preferable that the individual phase angles θ1, θ2, θ3, θ4 of the plurality of shims 4 are provided to be equal to each other.

  The shim 4 is a contact portion on the back surface 6 with the rotating shaft 31. The ratio (contact area ratio) of the area of the portion (at least a part of the shim 4) of the thrust needle bearing 20 that contacts the rotating shaft 31 with respect to the area of the back surface 6 is 5% or more and 20% or less.

  Next, a thrust needle bearing 20 including the bearing ring 10 according to Embodiment 1 will be described with reference to FIG. The thrust needle bearing 20 includes a bearing ring 10, a needle roller 7 that is provided to be able to roll on the raceway surface 5 of the bearing ring 10, and a retainer 8 that holds the needle roller 7 so that it can roll. The needle roller 7 has a crowning formed at an end portion of an outer diameter surface that comes into contact with the raceway surface 5. As described above, in the thrust needle bearing 20, the raceway surface 5 and the back surface 6 are inclined with respect to the axial direction. Therefore, when the thrust load is relatively small (for example, 70 N), the raceway surface 5 is in contact with the crowning portion of the needle roller 7. When the thrust load is relatively small (for example, 70 N), only the plurality of shims 4 are in contact with the rotating shaft 31 on the back surface 6.

Next, a method for manufacturing the bearing ring 10 according to Embodiment 1 will be described with reference to FIG.
First, the main body 1 and the shim 4 are prepared (step (S01)). As described above, the main body 1 includes the first portion 2 extending along the intersecting direction and the second portion 3 extending along the axial direction. The first part 2 has a track surface 5 and a back surface 6. The taper amount of the main body 1 is, for example, ± 50 μm or less. The main body 1 can be manufactured by, for example, a conventional method of manufacturing a race. For example, four shims 4 are prepared. Each shim 4 has the above-described configuration. Each shim 4 may be, for example, a commercially available shim. Further, each shim 4 can be manufactured by the same manufacturing method as the conventional shim.

  Next, the shim 4 is fixed to the back surface 6 of the main body 1 (step (S02)). When the taper amount of the main body 1 is positive, the plurality of shims 4 are fixed along the outer periphery of the main body 1 as shown in FIGS. The plurality of shims 4 are arranged at equal intervals in the circumferential direction. The back surface 6 and the shim 4 can be fixed to each other by any method, but are fixed to each other by, for example, bonding or welding. Thus, the bearing ring 10 according to Embodiment 1 is manufactured.

  Next, the operation and effect of the bearing ring 10 according to Embodiment 1 will be described. The bearing ring 10 is a bearing ring of the thrust needle bearing 20, and includes a raceway surface 5 and a back surface 6 located on a side opposite to the raceway surface 5. The raceway surface 5 and the back surface 6 each include an inclined surface with respect to the axial direction of the thrust needle bearing 20. Further, the back surface 6 includes a plurality of shims (projections) 4 protruding in the axial direction on the inclined surface. The plurality of shims (projections) 4 are arranged at intervals from one another along the circumferential direction of the bearing ring 10.

  In this way, since the back surface 6 located on the opposite side of the raceway surface 5 includes the plurality of shims (convex portions) 4, even when the thrust load applied to the raceway ring 10 is relatively small, for example, about 70N. The plurality of shims 4 can contact the rotating shaft 31 (bearing support member). Therefore, the vibration energy generated in the bearing ring 10 by the crowning portion of the needle roller 7 rolling with the raceway surface 5 can be converted into the elastic energy of the shim 4. In other words, the vibration of the bearing ring 10 is reduced by the elastic deformation of the shim 4 and is not easily transmitted to the rotating shaft 31 or the like, and the increase in noise is suppressed. The race 10 is easily manufactured by bonding the shim 4 formed separately from the main body 1 to the back surface 6. Therefore, the race 10 has a high quietness and a relatively low manufacturing cost. The manufacturing cost of the thrust needle bearing 20 including the bearing ring 10 is reduced as compared with a conventional thrust needle bearing including a vibration insulator or a needle roller that is super-finished.

  In the bearing ring 10, the protrusion 4 is elastically deformable. In this way, even when a state in which the thrust load applied to the bearing ring 10 is relatively small, for example, about 70 N, and a state in which the thrust load is larger than that are repeatedly realized, the convex portion 4 keeps the rotating shaft in the small state. 31 can be reproduced. Therefore, the vibration energy generated in the bearing ring 10 in the small state can be converted into the elastic energy of the projection 4. As a result, the vibration of the bearing ring 10 is alleviated by the elastic deformation of the shim 4, is not easily transmitted to the rotating shaft 31 and the like, and an increase in noise is suppressed. The bearing ring 10 is suitable for a thrust needle bearing applied to a mechanical device in which the state in which the thrust load is small and the state in which the thrust load is large are repeatedly realized.

  In the bearing ring 10, the convex portion 4 is configured separately from the bearing ring 10. The projection is configured as, for example, a shim 4. In this way, the bearing ring 10 can be easily obtained by the main body 1 and the shim 4 manufactured by the same method as the conventional manufacturing method of the bearing ring.

  In the bearing ring 10, three or more shims (projections) 4 are provided in the circumferential direction. In this way, even when the thrust load applied to the bearing ring 10 is relatively small, for example, about 70 N, three or more shims 4 can contact the rotating shaft 31 (bearing support member). Therefore, according to the bearing ring 10, since the contact state between the three or more shims 4 and the rotating shaft 31 is stable, the vibration of the bearing ring 10 is effectively caused by the elastic deformation of the three or more shims 4. Be relaxed.

  In the race 10, the shim (projection) 4 is preferably provided along the outer periphery of the race 10. When the taper amount of the bearing ring 10 is positive, the outer periphery of the bearing ring 10 is arranged at a position closest to the rotating shaft 31 in the axial direction. Therefore, if the plurality of shims 4 are provided along the outer circumference of the bearing ring 10, the plurality of shims 4 and the rotating shaft 31 can be easily brought into contact with each other, and a relatively small amount of the shim 4 is applied to the bearing ring 10. The shim 4 can also be elastically deformed by the thrust load. As a result, according to the bearing ring 10, the vibration of the bearing ring 10 is more reduced as compared with the case where the taper amount is positive and the shim 4 is arranged on the radially inner side with respect to the outer circumference. It can be effectively alleviated.

  In the plurality of shims (projections) 4, the total length of the plurality of shims (projections) 4 along the circumferential direction of the shim (projections) 4 on the radially inner side of the thrust needle bearing 20 is equal to the number of the shims (projections). It is preferably 10% or more and less than 50% of the length of the circumference of the circle contacting the inner diameter side of the part 4.

  With this configuration, since the shim 4 is provided discretely and partially in the circumferential direction, the contact portion of the race ring 10 with the rotating shaft 31 is provided discretely and partially in the circumferential direction. I have. Therefore, the vibration energy generated in the bearing ring 10 by the crowning portion of the needle roller 7 rolling with the raceway surface 5 can be converted into the elastic energy of the shim 4. If the contact length ratio is less than 10%, a portion of the bearing ring 10 that is elastically deformed becomes large and rigidity is reduced, and there is a possibility that the bearing ring 10 and the bearing support member (the rotating shaft 31) come into contact. On the other hand, if the contact length ratio exceeds 50%, the vibration energy cannot be sufficiently converted into elastic energy.

  On the plane orthogonal to the thrust direction, the bearing ring 10 has an average phase angle formed between the center point O of the bearing ring 10 in the radial direction and both circumferential ends of the plurality of shims (convex portions) 4 on the inner diameter side. However, it is preferable that it is 15 degrees or more and 30 degrees or less. With this configuration, even when the thrust load applied to the bearing ring 10 is relatively small, for example, about 70 N, the vibration energy generated in the bearing ring 10 due to the crowning portion of the needle roller 7 rolling with the raceway surface 5. Can be converted to the elastic energy of the shim 4. If the average phase angle is less than 15 degrees, there is a possibility that the bearing ring 10 and the bearing support member (the rotating shaft 31) come into contact with each other. On the other hand, if the average phase angle exceeds 30 degrees, the vibration energy cannot be sufficiently converted into the elastic energy.

  It is preferable that three or more shims (projections) 4 be provided in the race 10. Any number of shims (projections) 4 may be provided as long as the contact length ratio and the average phase angle satisfy the above conditions. By providing three or more shims 4, the contact state between the shim 4 of the bearing ring 10 and the rotating shaft 31 is stabilized. If the number of shims (projections) 4 is five or less, the manufacturing cost can be reduced.

  The thrust needle bearing 20 according to Embodiment 1 includes the bearing ring 10 and a needle roller 7 (rolling element) that rolls on the raceway surface 5 of the bearing ring 10. Since such a thrust needle bearing 20 is provided with the raceway 10 which is quiet and has a low manufacturing cost, the manufacturing cost is suppressed as compared with a conventional thrust needle bearing having a vibration insulator or a needle roller which is super-finished. ing.

  In the bearing ring 10 according to the first embodiment, the shim 4 is fixed to the back surface 6 by bonding or welding, but is not limited to this. The shim 4 may be simply sandwiched between the back surface 6 (first portion 2) and the rotating shaft 31 in the axial direction. Even in the bearing ring 10 having such a shim 4, the shim 4 is sandwiched between the back surface 6 and the rotating shaft 31 by applying a thrust load to the bearing ring 10. The same effect as described above can be obtained. Referring to FIG. 6, the method for manufacturing the bearing ring 10 basically has the same configuration as the method for manufacturing the bearing ring 10 shown in FIG. 5, but the shim 4 is fixed to the back surface 6. The difference is that a step (S03) of disposing the shim 4 between the back surface 6 and the rotating shaft 31 as a bearing support member is provided instead of the step (S02). That is, the bearing ring 10 is obtained by assembling the main body 1 and the shim 4 in the above-described positional relationship when incorporated into an arbitrary bearing device as the thrust needle bearing 20.

  Further, in the bearing ring 10 according to Embodiment 1, the shim 4 is provided along the outer periphery of the bearing ring 10, but is not limited to this. Referring to FIGS. 7 to 9, the plurality of shims 4 in the orbital ring 11 having the negative taper amount are preferably provided on the inner peripheral side of the orbital ring 11, and more preferably in the orbital ring 11. It is provided along the circumference. For example, when the connecting portion between the first portion 2 and the second portion 3 is provided along the inner circumference of the bearing ring 11, the plurality of shims 4 are provided along the connecting portion. In the bearing ring 11 having the negative taper amount, the inner circumference of the bearing ring 11 is disposed at a position closest to the rotating shaft 31 in the axial direction. Therefore, if the plurality of shims 4 are provided along the inner circumference of the bearing ring 11, the plurality of shims 4 and the rotating shaft 31 can be easily brought into contact with each other, and the relatively applied shim 4 is applied to the bearing ring 11. The shim 4 can be elastically deformed even by a small thrust load. As a result, according to the bearing ring 11, the vibration of the bearing ring 11 is more reduced as compared with the case where the amount of taper is negative and the shim 4 is arranged on the outer peripheral side in the radial direction than the inner periphery. It can be effectively alleviated. Referring to FIG. 22, when the connecting portion between first portion 2 and second portion 3 is provided along the outer periphery of bearing ring 11, a plurality of shims 4 are attached to first portion 2. It may be provided along the end located on the inner peripheral side.

(Embodiment 2)
Next, the race 12 according to the second embodiment will be described with reference to FIGS. The bearing ring 12 according to the second embodiment basically has the same configuration as the bearing rings 10 and 11 according to the first embodiment, but a plurality of irregularities (undulations) are formed on the back surface 6. The plurality of projections differ in that they are the tops 9 of the plurality of projections and depressions. In other words, the bearing ring 8 differs from the bearing rings 10 and 11 in that the top portion (convex portion) 8 is formed integrally with the back surface 6.

  The plurality of irregularities formed on the back surface 6 are provided periodically in the circumferential direction. The plurality of apexes (convex portions) 8 include a plurality of apexes of irregularities on the outer periphery of the bearing ring 12. The axial distance (amplitude) between the top of the plurality of irregularities on the outer periphery of the bearing ring 12 and the valley farthest from the top is preferably 100 μm or less.

  Also in the bearing ring 12, the average angle formed between the center point O of the bearing ring 12 and both circumferential ends of the plurality of tops 9 on the inner diameter side is 15 degrees or more and 30 degrees or less. Here, the average angle of the bearing ring 12 is obtained by dividing the total value of the phase angles θ1, θ2, θ3, and θ4 between the center point O and the circumferential ends of each of the tops 9 on the inner diameter side by the number of the tops 9. Mean value. In addition, the both ends in the circumferential direction of each apex 9 are portions that come into contact with the rotating shaft 31 when a thrust load of 70N is applied to the bearing ring 12 in a state where each apex 9 is in contact with the rotating shaft 31. Both ends, for example, including the vertex at the center in the circumferential direction. The individual phase angles θ1, θ2, θ3, θ4 of the plurality of tops 9 are preferably provided to be equal to each other.

  Next, a method for manufacturing the bearing ring 12 will be described with reference to FIG. First, a compact preparation step is performed as a step (S10). In this step (S10), a steel material containing an optional additive and comprising a balance of iron and impurities is prepared, and is subjected to a process such as forging or turning to have a shape corresponding to a desired shape of the inner ring. A molding is produced. More specifically, a molded body according to the shape of the inner ring having an inner diameter of 1000 mm or more is produced.

  Next, as a step (S15), a step of plastically deforming the formed body is performed. In this step (S15), the molded body is plastically deformed by being pressed against a jig having an uneven shape. When the taper amount of the molded body is positive, a jig capable of forming an uneven shape on the outer peripheral side of the molded body is used. When the taper amount of the molded body is negative, a jig capable of forming an uneven shape on the outer peripheral side of the molded body is used.

  Next, a normalizing step is performed as a step (S20). In this step (S20), after the molded body produced in step (S15) is heated to a temperature equal to or higher than the A1 transformation point and then cooled to a temperature lower than the A1 transformation point, a normalizing process is performed. . At this time, the cooling rate during the cooling in the normalizing treatment may be a cooling rate at which the steel constituting the compact does not transform into martensite, that is, a cooling rate lower than the critical cooling rate. The hardness of the molded body after the normalizing treatment increases as the cooling rate increases, and decreases as the cooling rate decreases. Therefore, by adjusting the cooling rate, a desired hardness can be imparted to the compact.

  Next, a quench hardening step is performed. The quench hardening step includes an induction heating step performed as a step (S30) and a cooling step performed as a step (S40). In the step (S30), the coil as the induction heating member is arranged so as to face a part of a rolling surface (annular region) on which the rolling element is to roll in the molded body. Next, the compact is rotated around the central axis, and a high-frequency current is supplied to the coil from a power supply (not shown). As a result, the surface layer region including the rolling surface of the formed body is induction-heated to a temperature of the point A1 or higher, and an annular heating region is formed along the rolling surface. At this time, the surface temperature of the rolling surface is measured and managed by a thermometer such as a radiation thermometer.

  Next, in the step (S40), for example, water as a cooling liquid is sprayed on the entire molded body including the heating area formed in the step (S30), so that the entire heating area is equal to or lower than the MS point. Simultaneously cooled to temperature. Thereby, the heating region is transformed into martensite and hardened. By the above procedure, induction hardening is performed, and the quench hardening step is completed.

  Next, a tempering step is performed as a step (S50). In this step (S50), the molded body quenched and hardened in steps (S30) and (S40) is placed in, for example, a furnace, heated to a temperature of point A1 or lower, and held for a predetermined time. , A tempering process is performed.

  Next, a finishing step is performed as a step (S60). In this step (S60), for example, finishing such as polishing is performed on the rolling surface. Through the above process, the race 12 of the thrust needle bearing 20 is manufactured.

  The orbital ring 12 having a positive taper amount has a plurality of apex portions 9 provided on the outer peripheral side of the orbital ring 11, and is more preferably provided along the outer periphery of the orbital ring 11. On the other hand, referring to FIG. 14, the orbital ring 13 having the negative taper amount has a plurality of tops 9 provided on the inner peripheral side of the orbital ring 11, and more preferably along the inner periphery of the orbital ring 11. It is provided as follows. For example, when the connecting portion between the first portion 2 and the second portion 3 is provided along the inner circumference of the bearing ring 11, the plurality of top portions 9 are provided along the connecting portion. Referring to FIG. 23, when the connecting portion between first portion 2 and second portion 3 is provided along the outer periphery of bearing ring 11, a plurality of tops 9 are provided on first portion 2. It may be provided along the inner peripheral end.

  In the bearing rings 12 and 13 according to the second embodiment, since the back surface 6 located on the opposite side of the bearing surface 5 includes a plurality of peaks (convex portions) 8, the thrust load applied to the bearing rings 12 and 13 is, for example, The plurality of tops 9 can be in contact with the rotating shaft 31 (bearing support member) even at a relatively small value of about 70N. Therefore, the vibration energy generated in the bearing rings 12 and 13 due to the rolling of the crowning portion of the needle roller 7 with the raceway surface 5 can be converted into the elastic energy of the top portion 9. As a result, the races 12, 13 can achieve the same effects as the races 10, 11.

  The races 10, 11, 12, 13 and the thrust needle bearing 20 according to the first and second embodiments can be applied to any mechanical device in which a thrust load acts on the rotating shaft, but the thrust load is relatively small. This is suitable for a mechanical device in which the state and the large state are repeatedly realized.

  In this example, the sound pressure of the thrust needle bearing including the bearing rings 10, 11, and 13 according to Embodiments 1 and 2 was measured to evaluate the quietness.

(sample)
Samples 1 to 5 were thrust needle bearings including the bearing rings 10, 11, and 13 according to Embodiments 1 and 2. Samples 6 and 7 were conventional thrust needle bearings as comparative examples. Samples 8 to 10 were conventional thrust needle bearings as reference examples. The thrust needle bearings of Samples 1 to 10 were composed of one race, a needle roller, and a retainer. The thrust needle bearings of samples 1 to 10 have a bearing ring outer diameter of 79.3 mm, a bearing ring inner diameter of 65.0 mm, a bearing ring thickness of 0.80 mm, a bearing ring height of 2.56 mm, and bearings including rollers. The height was 2.80 mm, the diameter of the needle roller was 2.00 mm, the length of the needle roller was 3.80 mm, the length of the crowning portion of the needle roller was 1.20 mm, and the number of needle rollers was 56.

  Sample 1 was a thrust needle bearing 20 having a bearing ring 10 in which three shims 4 were bonded to the back surface 6 at equal intervals in the circumferential direction. Each shim 4 had the same configuration. Each shim 4 was a rectangular parallelepiped having a short side length of 3 mm, a long side length of 10 mm, and a thickness of 10 μm. The material constituting each shim 4 was carbon tool steel SK2. The three shims 4 were adhered along the outer periphery of the back surface 6 respectively. The taper amount of the bearing ring 10 of the sample 1 was plus 50 μm. The needle roller 7 of the sample 1 had a crowning portion formed by barrel processing. In the needle roller 7, the roundness of the straight portion was 0.43 μm, and the roundness of the crowning portion was 1.24 μm.

  Specimen 2 was a thrust needle bearing 20 having a bearing ring 10 in which four shims 4 were adhered to the back surface 6 at equal intervals in the circumferential direction. Other configurations of the bearing ring 10 (the configuration of each shim 4 and the configuration of the main body 1) were the same as the bearing ring 10 of the sample 1.

  Sample 3 was a thrust needle bearing 20 provided with a bearing ring 10 in which five shims 4 were adhered to the back surface 6 at equal intervals in the circumferential direction. Other configurations of the bearing ring 10 (the configuration of each shim 4 and the configuration of the main body 1) were the same as the bearing ring 10 of the sample 1.

  The sample 4 was a thrust needle bearing 20 provided with a bearing ring 13 having three tops 9 formed at equal intervals along the inner periphery of the back surface 6. The amplitude (distance in the axial direction between the top and the valley adjacent to the top) and cycle (distance in the circumferential direction between the adjacent tops) of the three irregularities formed on the back surface 6 are all equal. did. The taper amount of the bearing ring 13 was −40 μm.

  The sample 5 was a thrust needle bearing 20 provided with a race 13 formed at regular intervals so that the four tops were along the inner periphery of the back surface 6. Other configurations of the race 13 were the same as the race 13 of the sample 4.

  Sample 6 was a conventional thrust needle bearing provided with a raceway having the above-mentioned taper amount of plus 50 μm. FIG. 15 is a cross-sectional view showing the thrust needle bearing 60 of the sample 6. The bearing ring 50 of the thrust needle bearing 60 has the same configuration as the main body of the thrust needle bearing 10 of the sample 1, and has a first portion 52 and a second portion 53. The needle roller 7 and the holder 8 of the thrust needle bearing 60 have the same configuration as the needle roller 7 and the holder 8 of the sample 1. That is, the thrust needle bearing 60 of the sample 6 is different from the thrust needle bearing 20 of the sample 1 in that the thrust needle bearing 60 does not include the plurality of shims 4.

  Sample 7 was a raceway of a conventional thrust needle bearing provided with a raceway having the above-mentioned taper amount of −40 μm. FIG. 16 is a cross-sectional view showing the thrust needle bearing 61 of the sample 7. The thrust needle bearing 61 of the sample 7 is different from the thrust needle bearing 20 of the sample 4 in that a plurality of tops 9 are not formed.

  The sample 8 is subjected to a press tempering process (a process of holding the bearing ring at a predetermined temperature in a state where the bearing ring is pressed against a mold to correct its shape) on a raceway of a conventional thrust needle bearing having a configuration equivalent to that of the sample 6. And the orbital ring having the taper amount of plus 5 μm. The needle rollers of Samples 2 to 8 had the same configuration as the needle roller 7 of Sample 1.

  Sample 9 was a thrust needle bearing including a raceway of a conventional thrust needle bearing having the same configuration as that of sample 6, and a straight roller having no crowning portion formed as a needle roller. The needle rollers had a roundness of 0.38 μm.

  Sample 10 includes a raceway of a conventional thrust needle bearing having a configuration equivalent to that of sample 6, and a needle roller in which a crowning portion formed by barrel processing is subjected to a lapping process using 2,000-grain abrasive paper. Equipped thrust needle bearing. In the needle roller, the roundness of the straight portion was 0.46 μm, and the roundness of the crowning portion was 0.52 μm.

  Table 1 shows the amount of taper of the bearing ring, the number of convex portions (shims, top portions), the contact area ratio, the contact length ratio, and the average phase angle for the thrust needle bearings of Samples 1 to 10.

(Evaluation)
First, with respect to the thrust needle bearings of Samples 2 and 5 as Examples and Samples 6 and 7 as Comparative Examples, the bearing ring and the bearing support member (rotating shaft) when a thrust load of 70 N was applied to the thrust needle bearing. ) Was confirmed. Specifically, a pressure-sensitive paper that develops color in response to pressure is sandwiched between a bearing support member and a back surface located on the opposite side to the raceway surface of the bearing ring, and a feeling when a thrust load of 70N is applied to the thrust needle bearing. The contact state was confirmed from the color distribution of the pressure paper. FIG. 17 shows the evaluation results of Sample 2. FIG. 18 shows the evaluation result of Sample 5. FIG. 19 shows the evaluation result of Sample 6. FIG. 20 shows the evaluation results of Sample 7. In the thrust needle bearings of Samples 6 and 7 shown in FIGS. 19 and 20, the races and the bearing support members are in uniform contact in the circumferential direction, whereas the thrust needle bearings shown in FIGS. In the thrust needle bearings 2 and 5, it was confirmed that the bearing ring and the bearing support member were in partial contact.

  Next, for the thrust needle bearings of Sample 1 to Sample 10, the noise level (sound pressure) when a thrust load of 70 N was applied to the thrust needle bearing was evaluated. The evaluation was performed by a method of measuring the noise level of a rolling bearing specified in JIS B 1548. The shaft rotation speed was 750 / min. FIG. 21 is a graph showing the measurement results of the noise level.

  It was confirmed that the noise levels of the thrust needle bearings of Samples 1 to 5 were reduced as compared with the thrust needle bearings of Samples 6 and 7. Further, it was confirmed that the noise levels of the thrust needle bearings of Samples 1 to 5 were equal to or lower than the noise levels of the thrust needle bearings of Samples 8 to 10 as reference examples. The thrust needle bearings of Samples 1 to 5 were manufactured by performing a process of bonding the shim 4 and the back surface 6 or a process of plastically deforming the molded body instead of the press tempering process on the raceway ring or the wrapping process on the needle roller. It is. The bonding step and the plastic deformation step can be performed at a lower cost as compared with the press tempering treatment, the lapping treatment, or the superfinishing for the needle roller. Therefore, it was confirmed that the thrust needle bearings of Samples 1 to 5 had the same quietness as the thrust needle bearings of Samples 8 to 10, though their production costs were lower.

  According to the races 10, 11, and 13 of Samples 1 to 5 in which the contact length ratio is 10% or more and less than 50%, the races of Samples 6 and 7 in which the contact length ratio is 100% are used. It has been confirmed that the noise level of the thrust needle bearing can be reduced in comparison. According to the races 10, 11, and 13 of the samples 1 to 5 having the contact area ratio of 5% or more and 20% or less, compared with the races of the samples 6 and 7 having the contact area ratio of 33% or more. Therefore, it was confirmed that the noise level of the thrust needle bearing could be reduced. Also, according to the races 10, 11, and 13 of the samples 1 to 5 in which the average phase angle is 15 degrees or more and 30 degrees or less, the sample 6 in which no convex portion is formed and the average phase angle cannot be defined. And 7, the noise level of the thrust needle bearing can be reduced.

  The embodiments and examples disclosed this time are to be considered in all respects as illustrative and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  DESCRIPTION OF SYMBOLS 1 Main body part, 1A one end, 1B other end, 2nd part, 3rd part, 4 shims (convex part), 5 track surfaces, 6 back surfaces, 7 needle rollers, 8 cages, 9 top parts (convex parts), 10, 11, 12, 13 races, 20 thrust needle bearings, 31 rotating shaft, 32 fixed shaft.

Claims (7)

A bearing ring of a thrust needle bearing,
A track surface, and a back surface located on the opposite side to the track surface,
The raceway surface and the back surface each include an inclined surface with respect to the axial direction of the thrust needle bearing,
Further, the back surface includes a plurality of protrusions protruding in the axial direction on the inclined surface,
The plurality of protrusions are arranged at intervals from each other along a circumferential direction of the bearing ring ,
The bearing ring, wherein the protrusion is provided along an outer periphery of the bearing ring. A bearing ring of a thrust needle bearing,
A track surface, and a back surface located on the opposite side to the track surface,
The raceway surface and the back surface each include an inclined surface with respect to the axial direction of the thrust needle bearing,
Further, the back surface includes a plurality of protrusions protruding in the axial direction on the inclined surface,
The plurality of protrusions are arranged at intervals from each other along a circumferential direction of the bearing ring,
The orbital ring, wherein the convex portion is provided along an inner circumference of the orbital ring. The bearing ring according to claim 1, wherein the projection is elastically deformable. Irregularities are formed on the back surface,
The bearing ring according to any one of claims 1 to 3, wherein the protrusion is a top of the unevenness. The race according to any one of claims 1 to 4, wherein the projection is configured separately from the race. The bearing ring according to any one of claims 1 to 5, wherein three or more convex portions are provided in the circumferential direction. A bearing ring according to any one of claims 1 to 6,
  A thrust needle bearing, comprising: a rolling element that rolls on the raceway surface of the raceway.

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