tapered roller bearings

Abstract

To provide a tapered roller bearing which can perform a sure inner-ring guide, and can prevent the wear of a cage.SOLUTION: In an inner-ring guide type tapered roller bearing 1 of the preset invention, a dimensionless number Y which is defined by the following formula by a small-diameter side clearance S1 between a small-diameter side annular part 6 of a cage 5 and a small flange part 2b of an inner ring 2, a large-diameter side clearance S2 between a large-diameter side annular part 7 of the cage 5 and a large flange part 2a of the inner ring 2, an average roller diameter d and a roller length I of tapered rollers 4, a pocket width W of the cage 5, a column angle θ being a half of an angle formed of faces contacting with the tapered rollers 4 between the adjacent column parts 8 of the cage 5 at a cross section corresponding to the average roller diameter d, a roller center diameter PCD being an alignment pitch roller diameter of the tapered rollers 4, and a cage inside diameter D is equal to or larger than 0.39, and equal to or smaller than 0.88. Y=(Smax / S3)×(d / l). Here, S3=(W / 2) / tanθ-(PCD / 2+(d / 2) / sinθ-((D / 2)2-(W / 2)2)1 / 2), and Smax is a maximum value of S1 and S2.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a tapered roller bearing that can be used in locations where centrifugal force acts, such as planetary reducer sections of construction machinery, and in particular in first-stage planetary sections where centrifugal force is large. [Background technology]

[0002] Typical tapered roller bearings are of the rolling element guided type, in which a cage 5 is guided by tapered rollers 4, as shown in Figure 11. However, for tapered roller bearings used in an orbiting environment, such as the planetary part of a planetary reducer, if the bearing is of the rolling element guided type, the centrifugal force generated by the revolution will result in low stability of cage behavior and significant wear to the column, so a bearing of the raceway guided type (inner ring guided or outer ring guided) is preferred.

[0003] 12A, 13A, 14A, and 15A show the operation of a tapered roller bearing using a rolling-element guided standard cage, while Figures 12B, 13B, 14B, and 15B show the operation of a tapered roller bearing using an inner ring guided cage capable of withstanding high centrifugal force. As shown in Figures 13A and 13B, when a tapered roller bearing is used for the planetary rotor 105 of a planetary reducer, centrifugal force G acts on the entire tapered roller bearing as it revolves as shown by arrow c. When a tapered roller bearing using an outer ring guided cage capable of withstanding high centrifugal force is used for the planetary rotor, centrifugal force G also acts on the entire tapered roller bearing.

[0004] When centrifugal force G due to revolution acts on the entire tapered roller bearing in this way, if we consider the interaction between the bearing components assuming that inner ring 2, which is the fixed raceway ring of the tapered roller bearing, is stationary, centrifugal force G will act to pull cage 5 in a direction away from the revolution axis, as shown in Figures 14A and 14B, which are vertical cross-sectional views of the area enclosed by a square in Figures 13A and 13B. In the rolling element guide type shown in Figure 14A, the gap S between the inner ring rib, particularly small rib portion 2b, and cage 5 is large, so when cage 5 is pulled in a direction away from the revolution axis by centrifugal force G, cage 5 will move a large amount in that direction, and as shown in Figure 15A, which is an enlarged horizontal cross-sectional view of the area enclosed by a square in Figure 13A, the gap δ between the inner surface of the pocket of post portion 8 of cage 5 and tapered roller 4 will disappear, and wear on the inner surface of the pocket of post portion 8 will increase.

[0005] However, in the inner ring guide type shown in Figure 14B, the gaps S1 and S2 between the inner ring rib portions (small rib portion 2b, large rib portion 2c) and the retainer 5 are small, so even if the retainer 5 is pulled in a direction away from the revolution axis by centrifugal force, the amount of movement of the retainer 5 in that direction is small, and as shown in Figure 15B, which is an enlarged cross-sectional view of the area surrounded by a square in Figure 13B, the gap δ between the inner surface of the pocket of the column portion 8 and the tapered roller 4 is maintained, and wear on the inner surface of the pocket of the column portion 8 does not increase.

[0006] As an inner ring guide type tapered roller bearing, there is one in which flange-shaped portions are provided on both the small diameter side and the large diameter side of the cage, and the inner peripheral edge thereof is used as the sliding surface, with the cage being guided by the inner ring (for example, Patent Document 1). [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Chinese Patent Application Publication No. 103410853 Summary of the Invention [Problem to be solved by the invention]

[0008] In an inner ring guide type tapered roller bearing, to ensure reliable inner ring guidance, it is necessary that the gap between the cage and the tapered rollers is always larger than the gap between the cage and the inner ring in all pockets. However, with bearings using the above-mentioned conventional technology, there are no particularly clear regulations regarding this gap relationship, so the gap between the cage and the tapered rollers tends to become excessively large, making it easier for the tapered rollers to skew (violation of the rotation axis of the tapered rollers) during operation and potentially leading to wear on the cage.

[0009] An object of the present invention is to provide an inner ring guide type tapered roller bearing that can realize reliable inner ring guidance while suppressing the occurrence of skew in the tapered rollers and preventing wear of the cage, etc. [Means for solving the problem]

[0010] The tapered roller bearing of the present invention is an inner ring guide type tapered roller bearing comprising an inner ring with double ribs, an outer member having an annular rolling surface facing the rolling surface of the inner ring, a plurality of tapered rollers interposed between the inner ring and the outer member, and a cage that holds the plurality of tapered rollers, wherein the cage has a small diameter side annular portion, a large diameter side annular portion, and a plurality of pillar portions in the circumferential direction that connect the small diameter side annular portion and the large diameter side annular portion, and pockets that hold the tapered rollers are formed between adjacent pillar portions, a small diameter side gap S1 that is the gap between the small diameter side annular portion and the small rib portion of the inner ring, a large diameter side gap S2 that is the gap between the large diameter side annular portion and the large rib portion of the inner ring, an average roller diameter d, a roller length l, a pocket width W that is the width of the pocket at a portion corresponding to the average roller diameter d, a column angle θ that is half the angle formed by the surfaces of adjacent column portions that contact the tapered rollers therebetween in a cross section corresponding to the average roller diameter d, a roller center diameter PCD that is the pitch circle diameter of the arrangement of the tapered rollers, and a cage inner diameter D that is the inner diameter of the cage, whereby a dimensionless number Y determined by the following formula (1) is 0.39 or more and 0.88 or less. Y=(S max / S3) × (d / l) … (1) However, S3 = (W / 2) / tanθ-(PCD / 2+(d / 2) / sinθ-((D / 2) 2 -(W / 2) 2 ) 1 / 2 ) S max is the maximum value of S1 and S2

[0011] In the tapered roller bearing of the present invention, the dimensionless number Y determined by the small diameter side gap S1, the large diameter side gap S2, the average roller diameter d, the roller length l, the pocket width W, the column angle θ, the roller centerline diameter PCD, and the cage inner diameter D using the formula (1) above is set to be 0.39 or more and 0.88 or less, thereby appropriately defining the gap between the cage and the inner ring and the gap between the cage and the tapered rollers, thereby realizing reliable inner ring guidance while suppressing the occurrence of tapered roller skew and preventing cage wear, etc.

[0012] In the tapered roller bearing of the present invention, the small diameter side annular portion and the large diameter side annular portion may each have a flange-like portion extending from the column portion toward the inner diameter side via an arc-shaped bent portion.

[0013] In the tapered roller bearing of the present invention, the cage may be formed by press working or turning.

[0014] In the tapered roller bearing of the present invention, a dimensionless number X determined by the small diameter side gap S1, the large diameter side gap S2, the average roller diameter d, the roller length l, and an outer member angle α, which is the angle formed by two generatrix lines in a cross section including the axis of a truncated cone formed by the rolling surface of the outer member, may be 0.69 or more and 1.12 or less, according to the following equation (2): X=(1 / tanα)×(1-(S1 / S2)×(d / l)) …(2) However, α is between 20° and 40° This additional configuration makes it possible to suppress the whirling of the cage (vibration of the rotation axis of the cage) and further prevent wear of the cage, even when the bearing is used in an environment in which it revolves.

[0015] In the tapered roller bearing of the present invention, the bending angle of the flange-shaped portion of the large diameter side annular portion relative to the column portion may be in the range of 90°±10° (or may be 80° or more and 100° or less) based on the cage angle, which is the angle at which the column portion is inclined with respect to the bearing axis. When the bending angle of the flange-shaped portion is in the range of 90°±10°, the cage has an appropriate shape for an inner ring guide type.

[0016] In the tapered roller bearing of the present invention, the radius of curvature of the inner diameter side surface of the bent portion to which the flange-shaped portion of the large diameter side annular portion is continuous may be greater than 20% and less than 90% of the length of the large diameter side annular portion in the direction in which the bar portions extend. If the radius of curvature of the inner diameter side surface of the bent portion of the large diameter side annular portion is 20% or less of the length of the large diameter side annular portion in the direction in which the bar portions extend, there is a concern that stress concentration will increase during bending of the cage, resulting in damage. If it is 90% or more, there is a concern that the arc shape of the inner diameter side surface of the bent portion will be too gentle, causing the end faces of the tapered rollers to come into edge contact with the opening edges of the pockets. If the radius of curvature is greater than 20% and less than 90%, such problems will not occur.

[0017] In the tapered roller bearing of the present invention, notched oil passages that allow lubricating oil to pass inside and outside the flange-shaped portion in the axial direction of the bearing may be provided at multiple locations on the inner peripheral edge of the flange-shaped portion. The provision of such oil passages makes it easier for lubricating oil to pass inside and outside the flange-shaped portion of the cage, ensuring good lubrication between the tapered rollers and the rolling surfaces and inner surfaces of the cage pockets.

[0018] In the tapered roller bearing of the present invention, the cross-sectional area ratio, which is the ratio of the vertical cross-sectional area of ​​the large diameter side annular portion to the vertical cross-sectional area of ​​the small diameter side annular portion, may be greater than 1.0 and less than 1.2. When this cross-sectional area ratio is greater than 1.0 and less than 1.2, the weight balance between the large diameter side and the small diameter side is appropriate, whirling of the cage is suppressed, and good inner ring guiding is achieved. [Effects of the Invention]

[0019] In the tapered roller bearing of the present invention, the dimensionless number Y determined by the small diameter side gap S1, the large diameter side gap S2, the average roller diameter d, the roller length l, the pocket width W, and the column angle 2Q using the formula (1) above is set to be 0.28 or more and 0.64 or less, thereby appropriately defining the gap between the cage and the inner ring and the gap between the cage and the tapered rollers, thereby realizing reliable inner ring guidance while suppressing the occurrence of tapered roller skew and preventing wear of the cage, etc. [Brief explanation of the drawings]

[0020] [Figure 1] 1 is a vertical cross-sectional view of a tapered roller bearing according to one embodiment of the present invention. [Figure 2] FIG. 2 is a vertical cross-sectional view of the retainer of the tapered roller bearing. [Figure 3A] FIG. 4 is an end view of the small diameter side end of the cage. [Figure 3B] FIG. 4 is an end view of the large diameter side end of the cage. [Figure 4] FIG. [Figure 5] FIG. 4 is a partially enlarged vertical cross-sectional view showing a large-diameter annular portion and tapered rollers of the cage in a further enlarged manner. [Figure 6] 4 is an explanatory diagram of centrifugal force acting on the tapered roller bearing in a planetary reducer using the tapered roller bearing. FIG. [Figure 7] 7 is a cross-sectional view taken along line VII-VII in FIG. 1, showing the column angle and the like in the tapered roller bearing. [Figure 8] 2 is a longitudinal sectional view showing an example of a planetary reducer using the tapered roller bearing. FIG. [Figure 9] FIG. 9 is a cross-sectional view taken along line IX-IX in FIG. 8. [Figure 10A] FIG. 1 is an explanatory diagram of an example of a gauge used for managing the clearance of a tapered roller bearing. [Figure 10B] FIG. 10 is an explanatory diagram of another example of a gauge used for managing the clearance of a tapered roller bearing. [Figure 11] FIG. 1 is a longitudinal sectional view of a conventional rolling element guided tapered roller bearing. [Figure 12A]FIG. 1 is an explanatory diagram of the action of centrifugal force on a rolling element guided tapered roller bearing. [Figure 12B] FIG. 1 is an explanatory diagram of the action of centrifugal force on an inner ring guide type tapered roller bearing. [Figure 13A] FIG. 1 is an explanatory diagram of the action of centrifugal force on a rolling element guided tapered roller bearing. [Figure 13B] FIG. 1 is an explanatory diagram of the action of centrifugal force on an inner ring guide type tapered roller bearing. [Figure 14A] FIG. 1 is an explanatory diagram of the action of centrifugal force on a rolling element guided tapered roller bearing. [Figure 14B] FIG. 1 is an explanatory diagram of the action of centrifugal force on an inner ring guide type tapered roller bearing. [Figure 15A] FIG. 1 is an explanatory diagram of the action of centrifugal force on a rolling element guided tapered roller bearing. [Figure 15B] FIG. 1 is an explanatory diagram of the action of centrifugal force on an inner ring guide type tapered roller bearing. DETAILED DESCRIPTION OF THE INVENTION

[0021] A tapered roller bearing according to one embodiment of the present invention will be described with reference to Figures 1 to 7. This tapered roller bearing 1 is used in a planetary portion of a planetary reducer or planetary transmission, which will be described later with reference to Figures 8 and 9.

[0022] In FIG. 1, this tapered roller bearing 1 comprises an inner ring 2, an outer member 3, a plurality of tapered rollers 4 interposed between the inner ring 2 and the outer member 3, and a cage 5 that holds the plurality of tapered rollers 4. The inner ring 2 has a tapered raceway surface 2a on its outer peripheral surface that increases in diameter from near one end to near the other end in the bearing axial direction (the direction of the bearing axis center O, also simply referred to as the axial direction), and is a double-rib component with a small rib portion 2b at one end and a large rib portion 2c at the other end. The outer member 3 is an annular component that faces the raceway surface 2a of the inner ring 2 and has a tapered raceway surface 3a that increases in diameter from one end to the other. The outer member 3 is a component that corresponds to an "outer ring" when it is a component that functions solely as a bearing, but is also a conceptual component that includes, for example, a component whose outer peripheral surface is a gear portion and has the raceway surface 3a on its inner peripheral surface, and is referred to as the "outer member" in this specification. In this specification, the "outer member" may be referred to as the "outer ring" in tests, analysis examples, etc. In the illustrated embodiment, the outer member 3 does not have a flange, but may have a flange portion (not shown) that protrudes toward the inner diameter side at one end or the other end.

[0023] The cage 5 has a small-diameter side annular portion 6, a large-diameter side annular portion 7, and column portions 8 at multiple locations in the circumferential direction connecting the small-diameter side annular portion 6 and the large-diameter side annular portion 7. The spaces between adjacent column portions 8 form pockets 9 that hold the tapered rollers 4. The inner diameter surfaces of the small-diameter side annular portion 6 and the large-diameter side annular portion 7 of the cage 5 have diameters that are guided by the small rib portion 2b and the large rib portion 2c of the inner ring 2, respectively. This makes the tapered roller bearing 1 an inner-ring guide type. Note that the cage 5 only needs to be an inner-ring guide type, and may be configured so that it is guided by only one of the small rib portion 2b and the large rib portion 2c of the inner ring 2. Basically, it is preferable that the cage be guided by at least the small rib portion 2b of the inner ring 2.

[0024] In this tapered roller bearing 1, the gaps S1, S2 between the cage 5 and the inner ring 2 and the gap S3 between the cage 5 and the tapered rollers 4 (FIG. 7) are specified as follows. That is, the dimensionless number Y determined by the following equation (1) is 0.39 or more and 0.88 or less, where Y is the gap between the small diameter side annular portion 6 of the cage 5 and the small rib portion 2b of the inner ring 2, the gap between the large diameter side annular portion 7 of the cage 5 and the large rib portion 2c of the inner ring 2, the average roller diameter d of the tapered rollers 4, the roller length l of the tapered rollers 4, the pocket width W (FIG. 7) which is the width of the pocket 9 at the portion corresponding to the average roller diameter d, the column angle θ which is half the angle formed by the surfaces of adjacent column portions 8 that contact the tapered rollers 4 therebetween in the cross section corresponding to the average roller diameter d, the roller center diameter PCD which is the pitch circle diameter of the arrangement of the tapered rollers 4, and the cage inner diameter D which is the inner diameter of the cage 5. As shown in FIG. 1, the subscript "1" indicates that it corresponds to the small diameter side, and the subscript "2" indicates that it corresponds to the large diameter side. Y=(S max / S3) × (d / l) … (1) However, S3 = (W / 2) / tanθ-(PCD / 2+(d / 2) / sinθ-((D / 2) 2 -(W / 2) 2 ) 1 / 2 ) S max is the maximum value of S1 and S2

[0025] The numerical limit for this dimensionless number Y was derived as follows: In an inner ring guide type tapered roller bearing 1, to ensure reliable inner ring guidance, it is necessary that the gap S3 between the cage 5 and the tapered rollers 4 is always larger than the gaps S1, S2 between the cage 5 and the inner ring 2 in all pockets 9, but if the gap S3 between the cage 5 and the tapered rollers 4 is excessively large, skew of the tapered rollers 4 (runout of the rotation axis of the tapered rollers 4) is more likely to occur during operation, which could lead to wear of the cage 5, etc.

[0026] Therefore, the aforementioned dimensionless number Y was devised as a parameter for evaluating the appropriateness of the clearances S1 and S2 between the cage 5 and the inner ring 2 and the clearance S3 between the cage 5 and the tapered rollers 4. Then, durability tests simulating a reducer were conducted on five types of tapered roller bearing sample Nos. (A) to (E) with different dimensionless numbers Y. As shown in Table 1, good results were obtained when the dimensionless number Y was between 0.39 and 0.88, and therefore this range was determined to be the appropriate range for the clearances S1 and S2 between the cage 5 and the inner ring 2 and the clearance S3 between the cage 5 and the tapered rollers 4.

[0027] [Table 1]

[0028] In this way, by setting the dimensionless number Y determined by the small diameter side gap S1, large diameter side gap S2, average roller diameter d, roller length l, pocket width W, column angle θ, roller center-to-center diameter PCD, and cage inner diameter D according to the above formula (1) to be between 0.39 and 0.88, the clearances S1 and S2 between the cage 5 and inner ring 2 and the clearance S3 between the cage 5 and tapered rollers 4 are appropriately defined, thereby realizing reliable inner ring guidance while suppressing the occurrence of skew in the tapered rollers 4 and preventing wear, etc., of the cage 5. As shown in FIG. 1, roller center-to-center diameter PCD is calculated from E3 / 2 + (d / 2) × cos(α / 2) using the inner ring raceway diameter E3, average roller diameter d, and outer member angle α, which will be described later. The inner ring raceway diameter E3 is calculated from (E1+E2) / 2 using the small rib portion side inner ring raceway diameter E1 and the large rib portion side inner ring raceway diameter E2.

[0029] Furthermore, in this tapered roller bearing 1, the small diameter side annular portion 6 and the large diameter side annular portion 7 of the cage 5 have flange-like portions 6a, 7a that extend from column portions 8 toward the inner diameter side via arc-shaped bent portions 6b, 7b. In this embodiment, the cage 5 is formed by pressing a metal plate such as an iron plate, with the small diameter side annular portion 6 and the large diameter side annular portion 7 formed by bending, and the columns 8 formed by punching out pockets 9 by pressing. Alternatively, the cage 5 may be formed by turning from metal, or may be a molded resin product.

[0030] Furthermore, in this tapered roller bearing 1, the dimensionless number X determined by the following equation (2) using the small diameter side gap S1, the large diameter side gap S2, the average roller diameter d, the roller length l, and the outer member angle α, which is the angle between two generatrix lines in a cross section including the axis of the truncated cone formed by the rolling surface 3a of the outer member 3, is equal to or greater than 0.69 and equal to or less than 1.12. However, the outer member angle α is set to be equal to or greater than 20° and equal to or less than 40° so that the bearing is adequately provided with both the ability to support an axial load and the ability to support a radial load. X=(1 / tanα)×(1-(S1 / S2)×(d / l)) …(2)

[0031] The numerical limit for this dimensionless number X was derived as follows: When an inner ring guide type tapered roller bearing 1 is used in an environment in which it revolves, centrifugal force G acts as described above, and therefore, in order to suppress the wobble of the cage 5 (wobble of the rotation axis of the cage 5), in addition to the clearances S1, S2 (small diameter side clearance S1 and large diameter side clearance S2) between the cage 5 and the inner ring 2 when stationary, the clearances between the cage 5 and the tapered rollers 4 when in operation (radial and axial clearances defined by the average roller diameter d and roller length l) must be managed.

[0032] Therefore, the aforementioned dimensionless number X was devised as a parameter for evaluating the appropriateness of the clearances S1, S2 between the cage 5 and inner ring 2 when stationary, and the clearance between the cage 5 and tapered rollers 4 during operation. Then, durability tests simulating a reducer were conducted on eight types of tapered roller bearing sample Nos. (1) to (8) with different dimensionless numbers X, and good results were obtained for a dimensionless number X of 0.69 or more and 1.12 or less, as shown in Table 2. Therefore, this range was determined to be the appropriate range for the clearances S1, S2 between the cage 5 and inner ring 2 when stationary, and the clearance between the cage 5 and tapered rollers 4 during operation.

[0033] [Table 2]

[0034] In this way, by setting the dimensionless number X determined by the small diameter side gap S1, the large diameter side gap S2, the average roller diameter d, the roller length l, and the outer member angle α using the above formula (2) to be 0.69 or more and 1.12 or less, the clearances S1 and S2 between the cage 5 and the inner ring 2 when stationary and the clearance between the cage 5 and the tapered rollers 4 during operation are appropriately defined, thereby suppressing whirling of the cage 5 and further preventing wear, etc. of the cage 5.

[0035] Furthermore, in this tapered roller bearing 1, the bending angle β that the flange-shaped portion 7a of the large diameter side annular portion 7 makes with respect to the column portion 8 is in the range of 90°±10° (80° or more and 100° or less) with respect to the cage angle, which is the angle at which the column portion 8 is inclined with respect to the bearing axis O. Since the bending angle β of the flange-shaped portion 7a is in the range of 90°±10°, the cage 5 has an appropriate shape for use as an inner ring guide type. The inner diameter surfaces of the small diameter side annular portion 6 and the large diameter side annular portion 7 are preferably parallel to the outer peripheral surfaces of the small rib portion 2b and the large rib portion 2c of the inner ring 2, respectively, but they may be inclined.

[0036] Furthermore, in this tapered roller bearing 1, as shown in Fig. 4, the radius of curvature b1 of the inner diameter side surface of the bent portion 7b to which the flange-shaped portion 7a of the large diameter side annular portion 7 is connected is greater than 20% and less than 90% of the length a of the large diameter side annular portion 7 in the direction in which the bar portions 8 extend. If the radius of curvature b1 of the inner diameter side surface of the bent portion 7b of the large diameter side annular portion 7 is 20% or less of the length a of the large diameter side annular portion 7b in the direction in which the bar portions 8 extend, there is a concern that stress concentration will increase during bending of the cage 5, resulting in damage. If it is 90% or more, there is a concern that the arc shape of the inner diameter side surface of the bent portion 7b will be too gentle, as shown by the thin line in Fig. 5, and the end faces of the tapered rollers 4 will come into contact with the opening edges of the pockets 9. If it is greater than 20% and less than 90%, there is no such problem.

[0037] Furthermore, as shown in Figures 3A and 3B, this tapered roller bearing 1 has notched oil passages 10, 11 at multiple locations on the inner peripheral edges of the flange-shaped portions 6a, 7a, which allow lubricating oil to pass inside and outside the flange-shaped portions 6a, 7a in the axial direction of the bearing. In this embodiment, the notched shapes of the oil passages 10, 11 are arcs, but they may also be elliptical arcs or other shapes. Also, only one of the small-diameter-side annular portion 6 and the large-diameter-side annular portion 7 may have a flange-shaped portion. The provision of such oil passages 10, 11 facilitates the passage of lubricating oil inside and outside the flange-shaped portions 6a, 7a of the cage 5, ensuring good lubrication between the tapered rollers 4 and the rolling surfaces 2a, 3a and the inner surfaces of the cage pockets, but the provision of the oil passages 10, 11 is not essential.

[0038] Furthermore, in this tapered roller bearing 1, as shown in the upper part of Figure 1, the cross-sectional area ratio, which is the ratio of the area of ​​the vertical cross section of the large diameter side annular portion 7 to the area of ​​the vertical cross section of the small diameter side annular portion 6, is greater than 1.0 and less than 1.2. When this cross-sectional area ratio is greater than 1.0 and less than 1.2, the weight balance between the large diameter side and the small diameter side is appropriate, whirling of the cage 5 is suppressed, and good inner ring guidance is achieved. In addition, when cutout oil passages 10, 11 are provided in the flange-shaped portions 6a, 7a of the small diameter side annular portion 6 and the large diameter side annular portion 7, as in the tapered roller bearing 1 of this embodiment, the area of ​​the vertical cross section of the small diameter side annular portion 6 mentioned above is the area of ​​the vertical cross section that does not pass through the oil passage 10 in the small diameter side annular portion 6 (the maximum value of the area of ​​the vertical cross section of the small diameter side annular portion 6), and the area of ​​the vertical cross section of the large diameter side annular portion 7 mentioned above is the area of ​​the vertical cross section that does not pass through the oil passage 11 in the large diameter side annular portion 7 (the maximum value of the area of ​​the vertical cross section of the large diameter side annular portion 7).

[0039] 8 and 9 show an example of a planetary reducer in which the tapered roller bearing 1 of this embodiment is used. In this planetary reducer, a plurality of planetary rotors 105 are arranged as planetary gears that mesh with both gears 102, 104, between a sun gear 102 attached to an input shaft 101 and an internal gear 104 fixed to a housing 103. Each planetary rotor 105 is rotatably supported by a carrier 107 connected to an output shaft 106, and the orbital motion of the planetary rotors 105, which revolve while rotating between the sun gear 102 and the internal gear 104, is output to the output shaft 106 via the carrier 107. This planetary reducer performs the first stage of reduction in a final drive unit provided inside the wheel rim of, for example, construction machinery.

[0040] A pair of tapered roller bearings 1 are arranged between a planetary rotor 105 and a carrier 107 of a planetary reducer. The outer member 3 (FIG. 1) of each tapered roller bearing 1 is attached to the planetary rotor 105 and rotates integrally with the planetary rotor 105. The inner ring 2 of each tapered roller bearing 1 is fixedly attached to a support shaft 108 provided on the carrier 107.

[0041] Note that the small-diameter side gap S1 and the large-diameter side gap S2 vary depending on factors such as insufficient crimping of the small-diameter side annular portion 6 of the cage 5 during assembly, so it is desirable to measure them appropriately to confirm that they are within an appropriate range. For example, to appropriately measure the small-diameter side gap S1, first, the spherical tip portion (e.g., having a predetermined diameter equal to the design value S1) of a reference gap gauge 51 shown in FIG. 10A is inserted between the small-diameter side annular portion 6 of the cage 5 and the small flange portion 2b of the inner ring 2 at an arbitrary circumferential position (defined as the 0° phase position), and then, at a 180° phase position opposite the 0° phase position in the radial direction, the small-diameter side gap S1 is measured using a plurality of measuring gap gauges 52 (each with a slightly different diameter at its cylindrical tip) shown in FIG. 10B. The same procedure is repeated, but with the phase position where the reference gap gauge 51 is inserted and the phase position where the measuring gap gauge 52 is used reversed, and the average of the small-diameter side gap S1 measured by both gauges is set as the reference gap.

[0042] When measuring appropriately, the spherical tip of a reference gap gauge 51 is inserted between the small diameter side annular portion 6 of the cage 5 and the small flange portion 2b of the inner ring 2 at an arbitrary circumferential position (defined as the 0° phase position) to set the 180° phase position to the reference gap, and the small diameter side gap S1 at the 180° phase position is measured using a measurement gap gauge 52 to confirm whether the small diameter side gap S1 is within a predetermined appropriate range compared to the reference gap. The large diameter side gap S2 can also be measured appropriately in the same way to confirm whether it is within the appropriate range.

[0043] Although the embodiments of the present invention have been described above, the disclosed embodiments are illustrative in all respects and are not restrictive. The scope of the present invention is defined by the claims rather than the above description, and it is intended to include all modifications within the scope and meaning equivalent to the claims. [Explanation of symbols]

[0044] 1...Tapered roller bearing 2...Inner circle 2a…Rolling surface 2b...small tsuba part 2c…Otsubabe 3...Outer member 3a…Rolling surface 4...Tapered roller 5...Cage 6...Small diameter annular section 6a...Flange-shaped part 6b...Bent part 7...Large diameter annular section 7a...Flange-shaped part 7b...Bent part 8...Column part 9...Pocket 10,11…Oil passage b1...Inner radius of curvature of the bent part d...Average roller diameter D...Cage inner diameter E1...Inner ring raceway diameter on small flange side E2...Inner ring raceway diameter on large flange side E3...Inner ring raceway diameter l...roller length O…Bearing axis PCD: Roller center diameter S1: Small diameter side clearance S2: Large diameter side clearance W…Pocket width X…Dimensionless number Y: dimensionless number α…Outer member angle β...bending angle θ…Column angle

Claims

1. An inner ring with double brims, an outer member having an annular rolling surface facing the rolling surface of the inner ring; a plurality of tapered rollers interposed between the inner ring and the outer member; a cage that holds the plurality of tapered rollers, the retainer has a small diameter side annular portion, a large diameter side annular portion, and pillar portions at a plurality of locations in the circumferential direction connecting the small diameter side annular portion and the large diameter side annular portion, and pockets for holding the tapered rollers are formed between adjacent pillar portions, A small diameter side gap S between the small diameter side annular portion and the small flange portion of the inner ring １ and a large diameter side gap S between the large diameter side annular portion and the large flange portion of the inner ring. ２ a dimensionless number Y determined by the following formula (1), which is equal to or greater than 0.39 and equal to or less than 0.88, where Y is an average roller diameter d, a roller length l, a pocket width W which is the width of a portion of the pocket corresponding to the average roller diameter d, a column angle θ which is half the angle formed by the surfaces of adjacent column portions which come into contact with the tapered rollers therebetween in a cross section corresponding to the average roller diameter d, a roller center diameter PCD which is the pitch circle diameter of the arrangement of the tapered rollers, and a cage inner diameter D which is the inner diameter of the cage, is equal to or greater than 0.39 and equal to or less than 0.88, Y=(S ｍａｘ / S ３ )×(d / l) …(1) However, S ３ =(W / 2) / tanθ-(PCD / 2+(d / 2) / sinθ-((D / 2) ２ -(W / 2) ２ ) １／２ ) S ｍａｘ is S １ and S ２ Maximum value of a dimensionless number X determined by the following formula (2) using the small diameter side gap S1, the large diameter side gap S2, the average roller diameter d, the roller length l, and an outer member angle α, which is the angle formed by two generatrix lines in a cross section including the axis of a truncated cone formed by the rolling surface of the outer member, is equal to or greater than 0.69 and equal to or less than 1.12, X=(1 / tanα)×(1-(S 1 / S 2 )×(d / l)) …(2) However, α is between 20° and 40° The tapered roller bearing is a tapered roller bearing used in a planetary part of a planetary reducer or a planetary transmission.

2. 2. The tapered roller bearing according to claim 1, wherein the small diameter side annular portion and the large diameter side annular portion have flange-like portions that extend from the column portion to the inner diameter side via an arc-shaped bent portion.

3. 3. A tapered roller bearing according to claim 1, wherein the cage is formed by pressing or turning.

4. 3. A tapered roller bearing according to claim 2, wherein the bending angle of the flange-shaped portion of the large diameter side annular portion relative to the column portion is in the range of 90°±10° based on a retainer angle, which is the angle at which the column portion is inclined relative to the bearing axis.

5. 3. A tapered roller bearing according to claim 2, wherein the radius of curvature of the inner diameter side surface of the bent portion to which the flange-shaped portion of the large diameter side annular portion is connected is greater than 20% and less than 90% of the length of the large diameter side annular portion in the direction in which the column portion extends.

6. 3. A tapered roller bearing according to claim 2, wherein notched oil passages are provided at a plurality of locations on the inner peripheral edge of the flange-shaped portion to allow lubricating oil to pass inside and outside the flange-shaped portion in the axial direction of the bearing.

7. 7. A tapered roller bearing according to claim 1, wherein a cross-sectional area ratio, which is the ratio of the area of ​​the longitudinal cross section of the large diameter side annular portion to the area of ​​the longitudinal cross section of the small diameter side annular portion, is greater than 1.0 and less than 1.2.

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