Tapered roller bearing

Abstract

The utility model provides a tapered roller bearing which has higher durability when being used as a tapered roller bearing for a chain wheel of a building machine. In a tapered roller bearing in which the number of tapered rollers (4) is 40 or more, the roller filling rate gamma% is 70% or more and less than 89%, and where W is the axial width of a cage (5), Dc is the outer diameter of a large-diameter-side annular portion (13) of the cage (5), P1 is the circumferential width of a small-diameter-side end portion of a column portion (15), and P2 is the circumferential width of a large-diameter-side end portion of the column portion (15), the roller filling rate gamma% is 70% or more and less than 89%, and W is the axial width of the cage (5), Dc is the outer diameter of the large-diameter-side annular portion (13), P1 is the circumferential width of the small-diameter-side end portion of the column portion (15). When the number of tapered rollers (4) is set as Z, the characteristic value A defined by A = (W * Dc) / (P1 * P2 * Z) is 2.0-8.0.

Description

Technical Field

[0001] The utility model relates to a tapered roller bearing. Background Art

[0002] As the lower traveling body of a construction machine, a lower traveling body using a crawler is widely known in order to be able to travel stably even on uneven ground. The crawler is hung between a crawler driving sprocket provided at one end of the lower traveling body in the traveling direction and a driven sprocket provided at the other end of the lower traveling body in the traveling direction, and is cyclically driven by rotating the crawler driving sprocket.

[0003] The rotation drive device of the crawler drive sprocket comprises: a fixed housing accommodating a hydraulic motor; a rotating housing rotatably supported by a bearing provided on the outer periphery of the fixed housing; and a speed reducer accommodated in the rotating housing. The crawler drive sprocket is fixed to the outer periphery of the rotating housing. When the hydraulic motor is operated, the rotation of the hydraulic motor is decelerated by the speed reducer and transmitted to the rotating housing, so that the crawler drive sprocket rotates integrally with the rotating housing.

[0004] Here, the bearing supporting the crawler drive sprocket (the bearing rotatably supporting the rotating housing) receives both radial load and thrust load, and therefore tapered roller bearings are often used (for example, see Patent Document 1).

[0005] The tapered roller bearing (hereinafter referred to as "tapered roller bearing for construction machinery sprocket") is capable of withstanding severe moment loads, as disclosed in Patent Document 1. Figure 5 In this way, the pitch diameter of the tapered roller is set larger, while the roller diameter of the tapered roller is set smaller. Therefore, the number of tapered rollers is larger than that of tapered roller bearings used for general purposes, and the number of tapered rollers is more than 40.

[0006] In addition, the tapered roller bearings for construction machinery sprockets bear a large load, so in order to ensure the durability of the bearings, they are designed to have a roller filling rate of more than 90%. The roller filling rate γ is a value defined by γ = (Da×Z)×100 / (π×PCD) when the number of tapered rollers is Z, the roller diameter of the tapered roller is Da, and the pitch circle diameter of the tapered roller is PCD.

[0007] Patent Document 1: Japanese Patent Application Publication No. 2007-127269 ( Figure 5 Figure 13)

[0008] The utility model of the present application has studied how to improve the durability of a tapered roller bearing for a construction machinery sprocket. As a result of the study, the following concept was obtained: in a tapered roller bearing for a construction machinery sprocket, a large load is easily applied to the retainer due to the deflection of the tapered roller (the phenomenon that the tapered roller is tilted relative to its traveling direction), so if the roller filling rate is set lower than before, the rigidity of the retainer is improved, thereby improving the overall durability of the tapered roller bearing for a construction machinery sprocket.

[0009] That is, the tapered roller bearing for the construction machinery sprocket is used under the conditions of low speed and high load. Therefore, there is a situation where the tapered roller is easily deflected, and the deflection applies a load to the retainer holding the tapered roller, thereby reducing the durability of the retainer. On the other hand, if the roller filling rate is set to be lower than before, the circumferential width of the column portion of the retainer becomes larger accordingly, so the rigidity of the retainer is improved, thereby improving the durability of the retainer. Here, when the roller filling rate is set to be lower, the surface pressure acting on the outer ring, inner ring, and tapered roller becomes higher, and there is a concern that the rolling fatigue life of the bearing will be reduced, but if the number of tapered rollers and the size of the pitch circle diameter of the tapered rollers are ensured, the durability of the outer ring, inner ring, and tapered roller can be ensured when used to support the crawler drive sprocket. Therefore, the following idea is obtained: if the roller filling rate is set to be lower than before, the overall durability of the tapered roller bearing for the construction machinery sprocket can be improved. Utility Model Content

[0010] The problem to be solved by the utility model is to provide a tapered roller bearing which has high durability when used as a tapered roller bearing for a sprocket of a construction machinery.

[0011] In order to solve the above-mentioned problems, the present invention provides a tapered roller bearing having the following structure.

[0012] [Structure 1]

[0013] A tapered roller bearing, comprising:

[0014] Outer ring;

[0015] An inner ring, which is arranged radially inward of the outer ring;

[0016] a plurality of tapered rollers assembled between the outer ring and the inner ring at intervals in the circumferential direction; and

[0017] a retainer that retains the plurality of tapered rollers,

[0018] The retainer comprises: a large diameter side annular portion extending in the circumferential direction along the large end surfaces of the plurality of tapered rollers, a small diameter side annular portion extending in the circumferential direction along the small end surfaces of the plurality of tapered rollers, and a plurality of column portions passing between the tapered rollers adjacent in the circumferential direction and connecting the large diameter side annular portion and the small diameter side annular portion.

[0019] A conical roller rolling surface is formed on the outer circumference of the tapered roller, which is in rolling contact with the outer ring and the inner ring.

[0020] The number of the plurality of tapered rollers is 40 or more.

[0021] The above-mentioned tapered roller bearing is characterized in that:

[0022] When the roller diameter obtained by averaging the diameter of the large diameter side end portion and the diameter of the small diameter side end portion of the roller rolling surface is set to Da (mm), the number of the plurality of tapered rollers is set to Z (pieces), and the pitch circle diameter of the plurality of tapered rollers is set to PCD (mm), the roller filling factor γ (%) defined by γ = (Da × Z) × 100 / (π × PCD) is 70% or more and less than 89%,

[0023] When the axial width of the retainer is W (mm), the outer diameter of the large diameter side annular portion of the retainer is Dc (mm), the circumferential width of the small diameter side end of the column portion is P1 (mm), and the circumferential width of the large diameter side end of the column portion is P2 (mm), the characteristic value A defined by A = (W × Dc) / (P1 × P2 × Z) is greater than 2.0 and less than 8.0.

[0024] If this structure is adopted, the roller filling rate γ (%) is set to less than 89%, so the circumferential width of the column portion of the retainer can be increased accordingly, thereby improving the rigidity of the retainer. In addition, the size of the retainer is set in such a way that the characteristic value A obtained by dividing the size of the retainer (W×Dc) by the circumferential width of the column portion and the number of column portions (P1×P2×Z) becomes 8.0 or less, so the rigidity of the retainer can be ensured when used as a tapered roller bearing for a construction machinery sprocket with low speed and high load. In addition, the size of the retainer is set in such a way that the characteristic value A becomes 2.0 or more, so the circumferential width of the column portion of the retainer does not become too large relative to the size of the retainer.

[0025] [Structure 2]

[0026] A tapered roller bearing, comprising:

[0027] Outer ring;

[0028] An inner ring, which is arranged radially inward of the outer ring;

[0029] a plurality of tapered rollers assembled between the outer ring and the inner ring at intervals in the circumferential direction; and

[0030] a retainer that retains the plurality of tapered rollers,

[0031] The retainer comprises: a large diameter side annular portion extending in the circumferential direction along the large end surfaces of the plurality of tapered rollers, a small diameter side annular portion extending in the circumferential direction along the small end surfaces of the plurality of tapered rollers, and a plurality of column portions passing between the tapered rollers adjacent in the circumferential direction and connecting the large diameter side annular portion and the small diameter side annular portion.

[0032] A conical outer ring raceway surface is formed on the inner periphery of the outer ring for the plurality of tapered rollers to roll in contact with.

[0033] A conical roller rolling surface is formed on the outer circumference of the tapered roller, which is in rolling contact with the outer ring and the inner ring.

[0034] The small diameter side annular portion of the retainer is formed with a small diameter side pocket surface facing the small end surface of each tapered roller.

[0035] The number of the plurality of tapered rollers is 40 or more.

[0036] The above-mentioned tapered roller bearing is characterized in that:

[0037] When the roller diameter obtained by averaging the diameter of the large diameter side end portion and the diameter of the small diameter side end portion of the roller rolling surface is set to Da (mm), the number of the plurality of tapered rollers is set to Z (pieces), and the pitch circle diameter of the plurality of tapered rollers is set to PCD (mm), the roller filling factor γ (%) defined by γ = (Da × Z) × 100 / (π × PCD) is 70% or more and less than 89%,

[0038] When the distance from the radial outer end of the small-diameter side pocket surface to the outer ring raceway surface is G (mm), and the outer diameter of the large-diameter side annular portion of the retainer is Dc (mm), the characteristic value B defined by B=Dc / G is not less than 100 and not more than 150. Here, the distance G is the size of the gap (radial gap) from the radial outer end of the small-diameter side pocket surface to the outer ring raceway surface directly above it in a state where the small-diameter side pocket surface of the retainer is in contact with the small end surface of the tapered roller.

[0039] If this structure is adopted, the roller filling rate γ (%) is set to less than 89%, so the circumferential width of the column portion of the retainer can be increased accordingly, thereby improving the rigidity of the retainer. In addition, the outer diameter size of the retainer is set in such a way that the characteristic value B obtained by dividing the outer diameter Dc of the large-diameter side annular portion of the retainer by G representing the size of the gap between the retainer and the outer ring is greater than 100, so the outer periphery of the retainer is close to the outer ring raceway surface. Therefore, the circumferential width of the column portion of the retainer becomes larger, which can effectively improve the rigidity of the retainer. In addition, since the characteristic value B is set to less than 150, the gap between the outer periphery of the retainer and the outer ring raceway surface will not become too narrow, which can prevent the retainer from contacting the outer ring raceway surface when the retainer is elastically deformed.

[0040] [Structure 3]

[0041] A tapered roller bearing according to structure 1 or 2, wherein:

[0042] A large flange is formed on the outer periphery of the inner ring for the large end surface of the tapered roller to contact with while sliding.

[0043] The roller rolling surface is subjected to overall crowning processing in such a manner that the entire roller rolling surface has a convex arc cross-section.

[0044] The vertex position of the circular arc of the overall crowning is offset toward the large end surface relative to the center of the tapered roller in the longitudinal direction of the roller rolling surface.

[0045] If this structure is adopted, the roller rolling surface on the outer circumference of the tapered roller is subjected to overall crowning, and the vertex position of the overall crowning is offset to one side of the large end face, so that the sliding resistance between the large end face of the tapered roller and the large flange of the inner ring can be suppressed to a low level, and the tapered roller is not easily deflected (the phenomenon that the tapered roller tilts relative to its running direction). Therefore, when used under low speed and high load conditions, the load on the retainer due to the deflection of the tapered roller can also be effectively reduced.

[0046] [Structure 4]

[0047] A tapered roller bearing according to any one of structures 1 to 3, wherein:

[0048] The roller diameter Da is less than 19 mm.

[0049] The plurality of tapered rollers have a pitch circle diameter PCD of 200 mm or more.

[0050] If this structure is adopted, it is suitable for use as a tapered roller bearing for a sprocket of construction machinery.

[0051] [Structure 5]

[0052] A tapered roller bearing according to any one of structures 1 to 4, wherein:

[0053] When the radial thickness of the outer ring at the position corresponding to the small end surface of the tapered roller is set to T1 (mm), the radial thickness of the outer ring at the position corresponding to the large end surface of the tapered roller is set to T2 (mm), and the bearing height which is the radial dimension from the inner circumference of the inner ring to the outer circumference of the outer ring is set to H (mm), the radial thickness T1 is not less than 30% and not more than 45% of the bearing height H, and the radial thickness T2 is not less than 10% and not more than 20% of the bearing height H.

[0054] With this structure, the rigidity of the outer ring can be ensured.

[0055] [Structure 6]

[0056] A tapered roller bearing according to any one of structures 1 to 5, wherein:

[0057] The large diameter side annular portion is formed with a large diameter side pocket surface facing the large end surface of each tapered roller.

[0058] The size of the gap δ between the large end surface of the tapered roller and the large diameter side pocket surface is less than 0.6 mm.

[0059] According to this structure, the cage can effectively suppress the deviation of the tapered roller.

[0060] [Structure 7]

[0061] A tapered roller bearing according to any one of structures 1 to 6, wherein:

[0062] Used for supporting the track drive sprocket of the drive track of construction machinery.

[0063] Since the roller filling rate γ (%) of the tapered roller bearing of the first utility model is set to less than 89%, the circumferential width of the column portion of the retainer can be increased accordingly, and the rigidity of the retainer can be improved. In addition, since the size of the retainer is set in such a way that the characteristic value A obtained by dividing the size of the retainer (W×Dc) by the circumferential width of the column portion and the number of column portions (P1×P2×Z) becomes less than 8.0, the rigidity of the retainer can be ensured when used as a tapered roller bearing for a construction machinery sprocket with a low speed and high load. Therefore, higher durability can be obtained when used as a tapered roller bearing for a construction machinery sprocket.

[0064] The tapered roller bearing of the second utility model is also set to a roller filling rate γ (%) of less than 89%, so the circumferential width of the column portion of the retainer can be increased accordingly, and the rigidity of the retainer can be improved. In addition, since the outer diameter dimension of the retainer is set in such a way that the characteristic value B obtained by dividing the outer diameter Dc of the large diameter side annular portion of the retainer by G representing the size of the gap between the retainer and the outer ring is greater than 100, the outer periphery of the retainer is close to the outer ring raceway surface. Therefore, the circumferential width of the column portion of the retainer becomes larger, which can effectively improve the rigidity of the retainer. Therefore, when used as a tapered roller bearing for a construction machinery sprocket, higher durability can be obtained. BRIEF DESCRIPTION OF THE DRAWINGS

[0065] Figure 1 This is a cross-sectional view of the tapered roller bearing according to the first embodiment of the present invention, taken along an axial plane.

[0066] Figure 2 It is enlarged to show Figure 1 Figure 4.

[0067] Figure 3 It is along Figure 2 Cross-sectional view along line III-III.

[0068] Figure 4 It is along Figure 2 A cross-sectional view taken along line IV-IV.

[0069] Figure 5 is exaggerated to show the Figure 1 FIG. 1 shows a diagram of the crowning of the outer circumference of a tapered roller.

[0070] Figure 6 This is a cross-sectional view of a tapered roller bearing according to a second embodiment of the present invention, taken along an axial plane.

[0071] Figure 7 It is enlarged to show Figure 6 Figure 4.

[0072] Figure 8 It is along Figure 7 A cross-sectional view taken along line VIII-III.

[0073] Fig. 9 It is along Figure 7 A cross-sectional view taken along line IX-IX.

[0074] Fig.10 It means that the assembly has Figure 1 (or Figure 6 ) is a cross-sectional view of a rotary drive device for a track drive sprocket with a tapered roller bearing as shown.

[0075] Description of Reference Numerals

[0076] 1… tapered roller bearing; 2… outer ring; 3… inner ring; 4… tapered roller; 5… cage; 6… outer ring raceway surface; 9… large flange; 10… roller rolling surface; 11… small end surface; 12… large end surface; 13… large diameter side annular portion; 14… small diameter side annular portion; 15… column portion; 17… large diameter side pocket surface; 18… small diameter side pocket surface; 20… track drive sprocket; 23… track; C… vertex position of the convex surface arc; Da …roller diameter of the tapered roller; Dc…outer diameter of the large-diameter annular portion; G…distance from the radial outer end of the small-diameter pocket surface to the outer ring raceway surface; H…bearing height; P1…circumferential width of the small-diameter end of the column; P2…circumferential width of the large-diameter end of the column; PCD…pitch diameter of the tapered roller; T1, T2…radial thickness of the outer ring; W…axial width of the retainer; δ…gap between the large end surface and the large-diameter pocket surface. DETAILED DESCRIPTION

[0077] Figure 1 A tapered roller bearing 1 according to a first embodiment of the present invention is shown. The tapered roller bearing 1 comprises: an outer ring 2; an inner ring 3 coaxially arranged radially inward of the outer ring 2; a plurality of tapered rollers 4 assembled between the outer ring 2 and the inner ring 3 at intervals in the circumferential direction; and an annular retainer 5 retaining the plurality of tapered rollers 4.

[0078] The outer ring 2 has a conical outer ring raceway 6 on its inner periphery for rolling contact with the tapered rollers 4. The inner ring 3 has a conical inner ring raceway 7 on its outer periphery for rolling contact with the tapered rollers 4, a small flange 8 projecting radially outward from the small diameter side end of the inner ring raceway 7, and a large flange 9 projecting radially outward from the large diameter side end of the inner ring raceway 7.

[0079] A conical roller rolling surface 10 is formed on the outer periphery of the tapered roller 4, which is in rolling contact with the outer ring raceway surface 6 and the inner ring raceway surface 7. In addition, a small end surface 11 is formed at the small diameter end of the tapered roller 4, which is opposite to the small flange 8 of the inner ring 3, and a large end surface 12 is formed at the large diameter end of the tapered roller 4, which is opposite to the large flange 9 of the inner ring 3.

[0080] The inner ring raceway surface 7 and the outer ring raceway surface 6 sandwich the tapered roller 4 and face each other in the radial direction. The outer ring raceway surface 6 and the inner ring raceway surface 7 are tapered surfaces that intersect at a common point O located on the center line of the inner ring 3. When the bearing rotates, each tapered roller 4 revolves around the center line of the inner ring 3 between the outer ring raceway surface 6 and the inner ring raceway surface 7 while rotating. The small flange 8 restricts the tapered roller 4 from moving to the small diameter side, preventing the tapered roller 4 from falling off the inner ring raceway surface 7. The large flange 9 contacts the large end surface 12 of the tapered roller 4 with sliding when the bearing rotates, supporting part of the axial load.

[0081] The retainer 5 includes: a large-diameter annular portion 13 extending circumferentially along the large end surface 12 of each tapered roller 4; a small-diameter annular portion 14 extending circumferentially along the small end surface 11 of each tapered roller 4; and a plurality of columnar portions 15 passing between the circumferentially adjacent tapered rollers 4 and connecting the large-diameter annular portion 13 with the small-diameter annular portion 14.

[0082] The large-diameter annular portion 13, the small-diameter annular portion 14, and the plurality of columnar portions 15 define a plurality of pockets 16 that respectively accommodate the plurality of tapered rollers 4. Here, the large-diameter annular portion 13 and the small-diameter annular portion 14 define the two axial ends of the pocket 16, and the columnar portion 15 defines the two circumferential ends of the pocket 16. The large-diameter annular portion 13 is formed with a large-diameter pocket surface 17 that faces the large end surface 12 of the tapered roller 4, and the small-diameter annular portion 14 is formed with a small-diameter pocket surface 18 that faces the small end surface 11 of the tapered roller 4.

[0083] The large diameter side annular portion 13, the small diameter side annular portion 14 and the plurality of pillar portions 15 constituting the retainer 5 are integrally formed of a resin composition in which a fiber reinforcement material is added to a resin material. As the resin material that becomes the matrix of the resin composition, polyamide 66 (PA66), polyamide 46 (PA46), polyphenylene sulfide (PPS), polyetheretherketone (PEEK), polynonamethylene terephthalamide (PA9T), polyamide 10T (PA10T) and the like can be used. As the fiber reinforcement material added to the resin material, glass fiber, carbon fiber, aromatic polyamide fiber and the like can be used.

[0084] The roller packing ratio γ of the tapered roller 4 of the tapered roller bearing 1 is set to be 70% or more (preferably 75% or more) and less than 89% (preferably 85% or less, more preferably 80% or less). The roller packing ratio γ is a value defined by γ=(Da×Z)×100 / (π×PCD) when the roller diameter of the tapered roller 4 is Da (mm), the number of tapered rollers 4 is Z (pieces), and the pitch circle diameter of the tapered roller 4 is PCD (mm).

[0085] Here, the roller diameter Da is a value obtained by averaging the diameter of the large diameter side end portion and the diameter of the small diameter side end portion of the roller rolling surface 10. In addition, the pitch circle diameter PCD of the tapered roller 4 is the diameter of an imaginary circle connecting the centers of the roller diameter Da portions of the plurality of tapered rollers 4 when the outer ring 2, the inner ring 3, and the tapered roller 4 are arranged in a regular position (there is no gap between the outer ring raceway surface 6 and the roller rolling surface 10, there is no gap between the inner ring raceway surface 7 and the roller rolling surface 10, and the large end surface 12 of the tapered roller 4 is in contact with the large flange 9. The same applies below).

[0086] The roller diameter Da is set to 19 mm or less (preferably 12 mm or less), and the pitch circle diameter PCD of the tapered roller 4 is set to 200 mm or more. That is, in order to withstand severe moment loads, the tapered roller bearing 1 sets the pitch circle diameter PCD of the tapered roller 4 to be larger, and on the other hand, sets the roller diameter Da of the tapered roller 4 to be smaller. Therefore, compared with tapered roller bearings used for general purposes, the number Z of tapered rollers 4 is larger, and the number of tapered rollers 4 is 40 or more (preferably 50 or more).

[0087] The axial width of the retainer 5 is W (mm), the outer diameter of the large-diameter annular portion 13 of the retainer 5 is Dc (mm), and the Figure 4 The circumferential width of the small diameter end of the column portion 15 is set to P1 (mm). Figure 3 When the circumferential width of the large diameter side end of the column portion 15 shown is set to P2 (mm), the dimensions of each part of the cage 5 are set so that the characteristic value A defined by A=(W×Dc) / (P1×P2×Z) is 2.0 or more and 8.0 or less. The number of column portions 15 is the same as the number Z of tapered rollers 4.

[0088] Here, if Figure 1 As shown, the axial width W of the retainer 5 is the axial distance from the axial end surface of the small-diameter side annular portion 14 on the side opposite to the tapered roller 4 (the left side in the figure) to the axial end surface of the large-diameter side annular portion 13 on the side opposite to the tapered roller 4 (the right side in the figure).

[0089] In addition, when the distance between the retainer 5 and the outer ring raceway surface 6 is G (mm) and the outer diameter of the large diameter side annular portion 13 of the retainer 5 is Dc (mm), the dimensions of the various parts of the retainer 5 are set so that the characteristic value B defined by B=Dc / G becomes 100 or more (preferably 120 or more) and 150 or less. Here, the distance G between the retainer 5 and the outer ring raceway surface 6 is the distance from the radial outer end of the small diameter side pocket surface 18 to the outer ring raceway surface 6 (the length of a perpendicular line descending from the radial outer end of the small diameter side pocket surface 18 to the outer ring raceway surface 6) in a state where the outer ring 2, the inner ring 3 and the tapered roller 4 are arranged in regular positions and the small diameter side pocket surface 18 of the retainer 5 is in contact with the small end surface 11 of the tapered roller 4.

[0090] In addition, the retainer 5 is formed such that the size of the gap δ between the large end face 12 and the large diameter pocket face 17 of the tapered roller 4 (the size of the gap δ measured in the axial direction of the tapered roller 4) is 0.01 mm or more and less than 0.6 mm, when the outer ring 2, the inner ring 3 and the tapered roller 4 are arranged in the proper positions and the small diameter side pocket face 18 of the retainer 5 is in contact with the small end face 11 of the tapered roller 4. Thus, the retainer 5 can suppress the deflection of the tapered roller 4 (the phenomenon that the tapered roller 4 tilts relative to its running direction).

[0091] The inclination angle θ of the outer ring raceway surface 6 relative to the center of the bearing is set to be not less than 10° and not more than 22.5°. When the radial thickness of the outer ring 2 at the position corresponding to the small end surface 11 of the tapered roller 4 is set to T1 (mm), the radial thickness of the outer ring 2 at the position corresponding to the large end surface 12 of the tapered roller 4 is set to T2 (mm), and the bearing height which is the radial dimension from the inner circumference of the inner ring 3 to the outer circumference of the outer ring 2 is set to H (mm), the radial thickness T1 is formed to be not less than 30% and not more than 45% of the bearing height H, and the radial thickness T2 is not less than 10% and not more than 20% of the bearing height H. Thus, the rigidity of the outer ring 2 is ensured. The inclination angle of the inner ring raceway surface 7 relative to the center of the bearing is set to be not less than 12.5° and not more than 20°.

[0092] like Figure 5 As shown in FIG. 1 , the roller rolling surface 10 is subjected to overall crowning so that the entire roller rolling surface 10 has a convex arc cross-section. Moreover, the overall crowning is formed so that the vertex position C of the arc is offset to the large end surface 12 side (left side in the figure) relative to the center in the longitudinal direction of the tapered roller 4. The offset amount of the vertex position C of the crowning relative to the center in the longitudinal direction of the tapered roller 4 is set to be not less than 10% and not more than 20% of the roller length L of the tapered roller 4.

[0093] Here, the vertex position C of the arc of the overall crowning is the position where the roller rolling surface 10 contacts the inner ring raceway surface 7 when the outer ring 2, the inner ring 3 and the tapered roller 4 are arranged in the normal position. In the figure, the crowning of the roller rolling surface 10 is exaggerated, but the actual crowning is a small crowning with a settlement amount (the amount of depression at both ends of the ideal conical surface before the crowning) of about 1 μm to 40 μm (preferably 3 μm to 40 μm).

[0094] Fig.10The rotary drive device of the crawler drive sprocket 20 using the above-mentioned tapered roller bearing 1 is shown. The rotary drive device comprises: a fixed housing 21 which accommodates a hydraulic motor (not shown); a tapered roller bearing 1 which is mounted on the outer periphery of the fixed housing 21; a rotating housing 22 which is supported by the tapered roller bearing 1 so as to be rotatable; and a planetary gear reducer (not shown) which is accommodated in the rotating housing 22. The crawler drive sprocket 20 is fixed to the outer periphery of the rotating housing 22, and a crawler 23 (crawler) of a construction machine is hung around the crawler drive sprocket 20. The rotary drive device is configured such that when the hydraulic motor (not shown) accommodated in the fixed housing 21 is operated, the rotation of the hydraulic motor is decelerated by the planetary gear reducer (not shown) accommodated in the rotating housing 22 and transmitted to the rotating housing 22, so that the crawler drive sprocket 20 rotates integrally with the rotating housing 22.

[0095] However, if Fig.10 As shown, the tapered roller bearing 1 used for supporting the track drive sprocket 20 of the driving track 23 of the construction machine is subjected to a large load, so in order to ensure the durability of the bearing, it is conventionally designed to have a roller filling rate of 90% or more. On the other hand, since the tapered roller bearing 1 used for supporting the track drive sprocket 20 of the driving track 23 of the construction machine is used under the conditions of low speed and high load, there is a possibility that the tapered roller 4 is easily deflected (the phenomenon that the tapered roller 4 is tilted relative to its running direction), and the deflection applies a load to the retainer 5 that retains the tapered roller 4, thereby reducing the durability of the retainer 5.

[0096] In view of this problem, the tapered roller bearing 1 of the present embodiment has a roller filling rate γ (%) set to less than 89% (preferably less than 85%, more preferably less than 80%), so that the circumferential width of the column portion 15 of the retainer 5 can be increased accordingly, and the rigidity of the retainer 5 can be improved. In addition, since the size of the retainer 5 is set in such a way that the characteristic value A obtained by dividing (W×Dc) representing the size of the retainer 5 by the circumferential width of the column portion 15 and the number of the column portions 15 (P1×P2×Z) becomes less than 8.0, as shown in FIG. Fig.10 As shown, even when used under low speed and high load conditions, the rigidity of the cage 5 can be ensured. Therefore, when used as a tapered roller bearing for a construction machinery sprocket, high durability can be obtained.

[0097] In addition, in the tapered roller bearing 1, the outer diameter dimension of the retainer 5 is set so that the characteristic value B obtained by dividing the outer diameter Dc of the large diameter side annular portion 13 of the retainer 5 by G indicating the size of the gap between the retainer 5 and the outer ring 2 becomes 100 or more (preferably 120 or more), so the outer periphery of the retainer 5 is close to the outer ring raceway surface 6. Therefore, the circumferential width of the column portion 15 of the retainer 5 becomes larger, and the rigidity of the retainer 5 can be effectively improved. Therefore, when used as a tapered roller bearing for a construction machinery sprocket, high durability can be obtained.

[0098] In addition, if Figure 5 As shown, the tapered roller bearing 1 is made by crowning the roller rolling surface 10 of the outer periphery of the tapered roller 4. The vertex position C of the crowning is offset to the large end surface 12. Figure 1 The sliding resistance between the large end face 12 of the tapered roller 4 and the large flange 9 of the inner ring 3 is suppressed to be low, and the tapered roller 4 is not easily deflected. Fig.10 As shown, even when used under low-speed and high-load conditions, the load on the cage 5 due to the deflection of the tapered roller 4 can be effectively reduced.

[0099] Figure 6 to Figure 9 A tapered roller bearing 1 according to a second embodiment of the present invention is shown. The second embodiment is different from the first embodiment in terms of the material of the retainer 5, and the other structures are the same. Therefore, the parts corresponding to the first embodiment are denoted by the same reference numerals and their description is omitted.

[0100] The large diameter annular portion 13, the small diameter annular portion 14 and the plurality of pillars 15 constituting the retainer 5 are formed of an iron plate formed into a conical shape by press forming. The material of the iron plate may be cold rolled steel plate (SPCC), hot rolled steel plate (SPHC), hot rolled mild steel plate (SPHD) or the like.

[0101] This tapered roller bearing 1 is also similar to the first embodiment. When the roller diameter of the tapered roller 4 is set to Da (mm), the number of the tapered rollers 4 is set to Z (pieces), and the pitch circle diameter of the tapered roller 4 is set to PCD (mm), the roller filling rate γ defined by γ = (Da × Z) × 100 / (π × PCD) is set to 70% or more (preferably 75% or more) and less than 89% (preferably 85% or less, more preferably 80% or less). Therefore, the circumferential width of the column 15 of the retainer 5 can be increased accordingly, and the rigidity of the retainer 5 can be improved. In addition, the size of the retainer 5 is set in such a way that the characteristic value A obtained by dividing (W × Dc) representing the size of the retainer 5 by the circumferential width of the column 15 and the number of the column 15 (P1 × P2 × Z) becomes 8.0 or less. Therefore, as shown in FIG. Fig.10As shown, even when used under low speed and high load conditions, the rigidity of the cage 5 can be ensured. Therefore, when used as a tapered roller bearing for a construction machinery sprocket, high durability can be obtained.

[0102] In addition, in the tapered roller bearing 1, the outer diameter dimension of the retainer 5 is set so that the characteristic value B obtained by dividing the outer diameter Dc of the large diameter side annular portion 13 of the retainer 5 by G indicating the size of the gap between the retainer 5 and the outer ring 2 becomes 100 or more (preferably 120 or more), so the outer periphery of the retainer 5 is close to the outer ring raceway surface 6. Therefore, the circumferential width of the column portion 15 of the retainer 5 becomes larger, and the rigidity of the retainer 5 can be effectively improved. Therefore, when used as a tapered roller bearing for a construction machinery sprocket, high durability can be obtained.

[0103] In addition, the tapered roller bearing 1 is provided with a crowning process on the roller rolling surface 10 of the outer circumference of the tapered roller 4, and the vertex position C of the crowning process is offset to the larger diameter side, so that the tapered roller bearing 1 can be Figure 6 The sliding resistance between the large end face 12 of the tapered roller 4 and the large flange 9 of the inner ring 3 is suppressed to be low, and the tapered roller 4 is not easily deflected. Fig.10 As shown, even when used under low speed and high load conditions, the load on the cage 5 due to the deflection of the tapered roller 4 can be effectively reduced. The other effects are the same as those of the first embodiment.

[0104] The embodiments disclosed this time should be understood to be illustrative in all aspects and not restrictive. The scope of the present invention is indicated by the claims rather than the above description, and is intended to include all modifications within the meaning and scope equivalent to the claims.

Claims

1. A tapered roller bearing comprising: Outer ring (2); An inner ring (3), the inner ring (3) being arranged radially inward of the outer ring (2); a plurality of tapered rollers (4) which are assembled between the outer ring (2) and the inner ring (3) at intervals in the circumferential direction; and a retainer (5) for retaining the plurality of tapered rollers (4), The retainer (5) comprises: a large-diameter annular portion (13) extending in the circumferential direction along the large end surfaces (12) of the plurality of tapered rollers (4), a small-diameter annular portion (14) extending in the circumferential direction along the small end surfaces (11) of the plurality of tapered rollers (4), and a plurality of columnar portions (15) connecting the large-diameter annular portion (13) and the small-diameter annular portion (14) between the tapered rollers (4) adjacent in the circumferential direction. A conical roller rolling surface (10) is formed on the outer periphery of the tapered roller (4) and is in rolling contact with the outer ring (2) and the inner ring (3). The number of the plurality of tapered rollers (4) is greater than 40, The tapered roller bearing is characterized in that: When the roller diameter obtained by averaging the diameter of the large diameter side end portion and the diameter of the small diameter side end portion of the roller rolling surface (10) is set as Da, the number of the plurality of tapered rollers (4) is set as Z, and the pitch circle diameter of the plurality of tapered rollers (4) is set as PCD, the roller filling rate γ defined by γ=(Da×Z)×100 / (π×PCD) is greater than 70% and less than 89%, When the axial width of the retainer (5) is set to W, the outer diameter of the large diameter side annular portion (13) of the retainer (5) is set to Dc, the circumferential width of the small diameter side end of the column portion (15) is set to P1, and the circumferential width of the large diameter side end of the column portion (15) is set to P2, the characteristic value A defined by A=(W×Dc) / (P1×P2×Z) is greater than 2.0 and less than 8.0, in, The units of Da, PCD, W, Dc, P1, and P2 are mm, the unit of Z is , and γ is expressed in %.

2. A tapered roller bearing comprising: Outer ring (2); An inner ring (3), the inner ring (3) being arranged radially inward of the outer ring (2); a plurality of tapered rollers (4) which are assembled between the outer ring (2) and the inner ring (3) at intervals in the circumferential direction; and a retainer (5), wherein the retainer (5) retains the plurality of tapered rollers (4), The retainer (5) comprises: a large-diameter annular portion (13) extending in the circumferential direction along the large end surfaces (12) of the plurality of tapered rollers (4), a small-diameter annular portion (14) extending in the circumferential direction along the small end surfaces (11) of the plurality of tapered rollers (4), and a plurality of columnar portions (15) connecting the large-diameter annular portion (13) and the small-diameter annular portion (14) between the tapered rollers (4) adjacent in the circumferential direction. A conical outer ring raceway surface (6) for the plurality of tapered rollers (4) to roll in contact with is formed on the inner periphery of the outer ring (2). A conical roller rolling surface (10) is formed on the outer periphery of the tapered roller (4) and is in rolling contact with the outer ring (2) and the inner ring (3). The small-diameter side annular portion (14) of the retainer (5) is formed with a small-diameter side pocket surface (18) facing the small end surface (11) of each tapered roller (4). The number of the plurality of tapered rollers (4) is greater than 40, The tapered roller bearing is characterized in that: When the roller diameter obtained by averaging the diameter of the large diameter side end portion and the diameter of the small diameter side end portion of the roller rolling surface (10) is set as Da, the number of the plurality of tapered rollers (4) is set as Z, and the pitch circle diameter of the plurality of tapered rollers (4) is set as PCD, the roller filling rate γ defined by γ=(Da×Z)×100 / (π×PCD) is greater than 70% and less than 89%, When the distance from the radial outer end of the small-diameter side pocket surface (18) to the outer ring raceway surface (6) is G and the outer diameter of the large-diameter side annular portion (13) of the retainer (5) is Dc, the characteristic value B defined by B=Dc / G is not less than 100 and not more than 150, in, The units of Da, PCD, G, and Dc are mm, the unit of Z is , and γ is expressed in %.

3. The tapered roller bearing according to claim 1 or 2, It is characterized in that A large flange (9) is formed on the outer periphery of the inner ring (3) for the large end surface (12) of the tapered roller (4) to contact while sliding. The roller rolling surface (10) is subjected to overall crowning processing in such a manner that the entire roller rolling surface (10) has a convex arc cross-section. The vertex position (C) of the circular arc of the integral crowning is offset toward one side of the large end surface (12) relative to the center of the tapered roller (4) in the length direction of the roller rolling surface (10).

4. The tapered roller bearing according to claim 1 or 2, It is characterized in that The roller diameter Da is less than 19 mm, The pitch circle diameter PCD of the plurality of tapered rollers (4) is greater than 200 mm.

5. The tapered roller bearing according to claim 1 or 2, It is characterized in that When the radial thickness of the outer ring (2) at a position corresponding to the small end face (11) of the tapered roller (4) is set to T1, the radial thickness of the outer ring (2) at a position corresponding to the large end face (12) of the tapered roller (4) is set to T2, and the bearing height which is the radial dimension from the inner circumference of the inner ring (3) to the outer circumference of the outer ring (2) is set to H, the radial thickness T1 is not less than 30% and not more than 45% of the bearing height H, and the radial thickness T2 is not less than 10% and not more than 20% of the bearing height H, Wherein, the units of T1, T2 and H are mm.

6. The tapered roller bearing according to claim 1 or 2, It is characterized in that The large-diameter side annular portion (13) is provided with a large-diameter side pocket surface (17) facing the large end surface (12) of each tapered roller (4). The size of the gap δ between the large end surface (12) of the tapered roller (4) and the large diameter side pocket surface (17) is less than 0.6 mm.

7. The tapered roller bearing according to claim 1 or 2, It is characterized in that The invention is used for supporting a crawler drive sprocket (20) of a driving crawler (23) of a construction machine.

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