Sealing equipment

Abstract

This sealing device is disposed between an outer member and an inner member of a rolling bearing, to seal a gap between the inner member and the outer member, which rotate relative to one another. The sealing device includes an annular rigid portion which is formed from a rigid material and which is fixed inside a hole in the outer member, and a resilient portion which is formed from a resilient material and which is fixed to the rigid portion. The resilient portion includes a frustoconical annular seal lip in slidable contact with the inner member or a member fixed to the inner member. A plurality of projections which are in constant slidable contact with the inner member or the member fixed to the inner member are formed on an inner circumferential surface of the seal lip, and gaps exist between the seal lip and the inner member or the member fixed to the inner member, in parts around the projections.

Description

Sealing device

[0001] The present invention relates to a sealing device for sealing the interior of a rolling bearing.

[0002] Patent Document 1 discloses a rolling bearing used in a railway vehicle. In a rolling bearing, the temperature changes due to heat generated by friction between rolling elements and surrounding parts, and the internal pressure fluctuates. A sealing device for sealing the internal lubricating oil is provided in the rolling bearing, and the sealing device slidably contacts the rotating inner ring. As the internal pressure of the bearing changes, the sealing device contacts the inner ring with a strong force and generates heat due to friction. In order to suppress this heat generation, the bearing disclosed in Patent Document 1 is provided with a plug for air venting.

[0003] Japanese Utility Model Laid-Open No. 4-123871

[0004] Different from the technology of Patent Document 1, it is also conceivable to suppress the heat generation of the sealing device by the sealing device itself provided in the bearing. In this case, it is desirable to ensure the sealing performance of the lubricating oil (grease), which is a function of the sealing device.

[0005] Therefore, the present invention provides a sealing device having high sealing performance of lubricating oil and capable of reducing the risk of heat generation due to friction even when the pressure inside the bearing increases or decreases.

[0006] A sealing device according to an aspect of the present invention is a sealing device disposed between a relatively rotating inner member and an outer member of a rolling bearing, for sealing a gap between the inner member and the outer member, and includes an annular rigid portion formed of a rigid material and fixed inside a hole of the outer member, and an elastic portion formed of an elastic material and fixed to the rigid portion. The elastic portion has a truncated conical annular seal lip that slidably contacts the inner member or a member fixed to the inner member. A plurality of protrusions that always slidably contact the inner member or a member fixed to the inner member are formed on an inner peripheral surface of the seal lip, and a gap exists between the seal lip and the inner member or a member fixed to the inner member at a portion around the protrusions.

[0007] In this embodiment, the seal lip slidably contacts the inner member or a member fixed to the inner member to seal the lubricating oil inside the bearing. Therefore, the sealing performance of the lubricating oil is high. On the other hand, multiple protrusions formed on the inner circumferential surface of the seal lip are always in contact with the inner member or a member fixed to the inner member, and a small gap exists between the seal lip and the inner member or the member fixed to the inner member in the portion around the protrusions. Air can flow between the inside and outside of the bearing through this small gap, and even if the pressure inside the bearing increases or decreases, the seal lip and / or other lips are not pressed against or attracted to the inner member or the member fixed to the inner member, thus reducing the risk of heat generation due to friction.

[0008] This is a cross-sectional view of a sealing device according to the first embodiment of the present invention. This is a front view showing the protrusions of the sealing device in Figure 1. This is a cross-sectional view taken along the line III-III in Figure 2. This diagram shows the arrangement of protrusions in the seal lip of the sealing device in Figure 1. This is a cross-sectional view showing the seal lip formed by a mold. This is a front view showing a part of the seal lip. This is a cross-sectional view of a sealing device according to the second embodiment of the present invention. This is a perspective view showing the rigid body portion of the sealing device in Figure 7. This is a cross-sectional view of the sealing device in Figure 7 being removed from a rolling bearing. This is a cross-sectional view of a sealing device according to the third embodiment of the present invention.

[0009] Various embodiments of the present invention will be described below with reference to the attached drawings. The scale in the drawings does not necessarily accurately represent the products of the embodiments, and some dimensions may be exaggerated.

[0010] First Embodiment Figure 1 shows a rolling bearing 2 of a railway vehicle, which is an example of a rolling bearing 2 in which a sealing device 1 according to an embodiment of the present invention is used. However, the applications of the present invention are not limited to rolling bearings of railway vehicles, and the present invention can also be applied to rolling bearings of large vehicles such as trucks and buses. Furthermore, although the rolling bearing 2 shown is an RCT (Rotating End Cap Tapered Roller) bearing, the applications of the present invention are not limited to RCT bearings, and the present invention can also be applied to other rolling bearings having other types of rolling elements, such as RCC (Rotating End Cap Cylindrical Roller) bearings, ball bearings, and needle bearings.

[0011] As shown in Figure 1, the rolling bearing 2 includes an inner ring (inner member) 6 into which the axle 4 is inserted, an outer ring (outer member) 8 positioned outside the inner ring 6, a plurality of rollers 10 arranged in a row between the inner ring 6 and the outer ring 8, an oil drain member (inner member) 12 into which the axle 4 is inserted, and a cage 14 that holds the rollers 10 in place. The outer ring 8 is fixed, while the inner ring 6 and the oil drain member 12 rotate with the rotation of the axle 4. The cage 14 is fixed to the outer ring 8.

[0012] The oil-sealing member 12 has a cylindrical portion 12A having an outer diameter and inner diameter approximately the same as the outer diameter and inner diameter of the inner ring 6, a flange 12B extending outward from the atmospheric side A end of the cylindrical portion 12A, and an outer cylindrical portion 12C extending from the outer end of the flange 12B toward the bearing interior side B. The cylindrical portion 12A, flange 12B, and outer cylindrical portion 12C define the circumferential groove 12D. In Figure 1, the oil-sealing member 12 is shown by dashed lines.

[0013] The sealing device 1 is positioned between the relatively rotating oil-cutting member 12 and the outer ring 8, sealing the gap between the oil-cutting member 12 and the outer ring 8. The sealing device 1 prevents or reduces the outflow of grease, i.e., lubricant, from inside the rolling bearing 2, and also prevents or reduces the inflow of foreign matter (water (including muddy water or saltwater) and / or dust (including iron powder)) from the outside into the rolling bearing 2. In Figure 1, arrow D shows an example of the direction of flow of foreign matter from the outside.

[0014] In Figure 1, only the left-side portion relative to the axle 4 is shown, but the sealing device 1 and the rolling bearing 2 have a rotationally symmetrical shape. The upper side of Figure 1 is the inside of the bearing B, and the lower side is the atmospheric side A. However, a sealing device similar to the sealing device 1 is also provided on the opposite side of the rolling bearing 2 from the sealing device 1.

[0015] The sealing device 1 has three annular sealing members, namely an outer sealing member 16, an intermediate sealing member 18, and an inner sealing member 20.

[0016] The outer sealing member 16 is formed from a rigid material, such as metal. The outer sealing member 16 has an outer cylindrical portion 16A, an annular portion 16B, an intermediate cylindrical portion 16C, an annular portion 16D, and an inner cylindrical portion 16E, which are fixed to the hole 8A of the outer ring 8. The cylindrical portions 16A, 16C, and 16E are coaxial cylinders.

[0017] The outer cylindrical portion 16A is fixed to the inner circumferential surface of the hole 8A of the outer ring 8 by interference fit. The end portion 16Aa of the outer cylindrical portion 16A on the bearing interior side B is formed as a hook that widens radially outward. A projection 8B extending in the circumferential direction is formed in the hole 8A, and a circumferential groove is formed in the end portion 16Aa of the outer cylindrical portion 16A into which the projection 8B is fitted.

[0018] The annular portion 16B extends radially inward from the atmospheric-side end A of the outer cylindrical portion 16A. The annular portion 16B extends in a plane perpendicular to the axial direction of the axle 4.

[0019] The intermediate cylindrical portion 16C extends from the inner end of the annular portion 16B toward the atmosphere side A.

[0020] The annular portion 16D extends radially inward from the atmospheric-side end A of the intermediate cylindrical portion 16C. The annular portion 16D extends in a plane perpendicular to the axial direction of the axle 4.

[0021] The inner cylindrical portion 16E extends from the inner end of the annular portion 16D toward the atmosphere side A. An annular gap is provided between the inner circumferential surface of the inner cylindrical portion 16E and the outer circumferential surface of the outer cylindrical portion 12C of the oil-cutting member 12.

[0022] The intermediate sealing member 18 is made of a rigid material, such as metal. The intermediate sealing member 18 has an outer cylindrical portion 18A, an annular portion 18B, and an inner cylindrical portion 18C, which are fixed to the outer sealing member 16. The cylindrical portions 18A and 18C are coaxial cylinders.

[0023] The outer cylindrical portion 18A is fixed to the inner circumferential surface of the intermediate cylindrical portion 16C of the outer sealing member 16 by an interlocking fit.

[0024] The annular portion 18B extends radially inward from the end of the bearing-inside B of the outer cylindrical portion 18A. The annular portion 18B extends in a plane that is almost perpendicular to the axial direction of the axle 4, but is curved.

[0025] The inner cylindrical portion 18C extends from the inner end of the annular portion 18B toward the bearing interior side B. An annular gap is provided between the inner circumferential surface of the inner cylindrical portion 18c and the outer circumferential surface of the cylindrical portion 12A of the oil drain member 12.

[0026] The inner sealing member 20 is positioned inside the outer sealing member 16 and the intermediate sealing member 18, and is positioned between the relatively rotating outer sealing member 16 and the oil draining member 12, sealing the gap between the outer sealing member 16 and the oil draining member 12. Therefore, the inner sealing member 20 can be considered a sealing device.

[0027] The inner sealing member (sealing device) 20 has a double structure comprising a rigid part 22 made of a rigid material, such as metal, and an elastic part 24 made of an elastic material, such as elastomer. The elastic part 24 is fixed to the rigid part 22, and the rigid part 22 reinforces the elastic part 24.

[0028] The inner sealing member 20 has a mounting cylindrical portion 26, an annular portion 28, a sealing lip (grease lip) 30, a secondary lip (dust lip) 32, and a side lip (dust lip) 34, which are fixed to the intermediate sealing member 18.

[0029] The mounting cylindrical portion 26 has a rigid portion 22 and an elastic portion 24, and is fixed to the inner circumferential surface of the outer cylindrical portion 18A of the intermediate sealing member 18 by interference fit.

[0030] The annular portion 28 has a rigid portion 22 and an elastic portion 24, and extends radially inward from the mounting cylindrical portion 26.

[0031] The elastic portion 24 has lips 30, 32, and 34.

[0032] The seal lip 30 is a frustoconical radial lip that extends diagonally inward from the inner end of the annular portion 28 toward the bearing interior side B. The seal lip 30 extends toward the outer circumferential surface of the cylindrical portion 12A of the oil-cutting member 12, and the tip of the seal lip 30 slidably contacts the outer circumferential surface of the cylindrical portion 12A over its entire circumference. The seal lip 30 primarily serves to prevent or reduce the leakage of lubricating oil from the bearing interior side B to the atmosphere side A.

[0033] The sub-lip 32 is a frustoconical radial lip that extends diagonally inward and toward the atmosphere side A from the inner end of the annular portion 28. The sub-lip 32 is positioned inside the circumferential groove 12D of the oil-sealing member 12 and extends toward the outer circumferential surface of the cylindrical portion 12A of the oil-sealing member 12. In this embodiment, the tip of the sub-lip 32 is in slidable contact with the outer circumferential surface of the cylindrical portion 12A of the oil-sealing member 12 over its entire circumference. The sub-lip 32 mainly has the function of preventing or reducing the intrusion of foreign matter from the atmosphere side A to the inside of the bearing B, and also has the function of preventing or reducing the leakage of lubricating oil from the inside of the bearing B to the atmosphere side A.

[0034] The side lip 34 is a frustoconical radial lip that extends diagonally outward and toward the atmosphere side A from the inner end of the annular portion 28. The side lip 34 is positioned inside the circumferential groove 12D of the oil drain member 12 and extends toward the inner circumferential surface of the outer cylindrical portion 12C of the oil drain member 12. In this embodiment, the tip of the side lip 34 is in slidable contact with the inner circumferential surface of the outer cylindrical portion 12C of the oil drain member 12 over its entire circumference. The side lip 34 mainly has the function of preventing or reducing the intrusion of foreign matter from the atmosphere side A to the inside of the bearing B, and also has the function of preventing or reducing the leakage of lubricating oil from the inside of the bearing B to the atmosphere side A.

[0035] Multiple protrusions 36 are formed on the inner circumferential surface of the seal lip 30. As shown in Figures 2 and 3, each protrusion 36 is positioned to be in contact with the leading edge 30A of the seal lip 30. Each protrusion 36 has a parallel surface 36A, an inclined surface 36B, and a vertical surface 36C. The parallel surface 36A is a flat surface parallel to the inner circumferential surface of the seal lip 30. The inclined surface 36B is continuous with the parallel surface 36A and its height gradually decreases from the parallel surface 36A toward the inner circumferential surface of the seal lip 30. The vertical surface 36C is perpendicular to the parallel surface 36A and the inner circumferential surface of the seal lip 30 and is flush with the leading edge 30A of the seal lip 30.

[0036] As shown in Figure 4, in this embodiment, three sets of two projections 36 are provided. These three sets are arranged at equal angular intervals, i.e., 120-degree intervals. However, the arrangement and number of projections 36 are not limited to this embodiment.

[0037] These protrusions 36 are always in slidable contact with the outer circumferential surface of the cylindrical portion 12A of the oil drain member 12. Therefore, on the inner circumferential surface of the seal lip 30 shown in Figure 4, the portion 30B away from the protrusions 36 is in contact with the outer circumferential surface of the cylindrical portion 12A of the oil drain member 12, but in the portion 30C around the protrusions 36, there is a gap between the seal lip 30 and the cylindrical portion 12A.

[0038] In this embodiment, as described above, the seal lip 30 slidably contacts the outer circumferential surface of the cylindrical portion 12A of the oil-cutting member 12, thereby sealing the lubricating oil inside the rolling bearing 2. Therefore, the sealing performance of the lubricating oil is high.

[0039] On the other hand, the multiple protrusions 36 formed on the inner circumferential surface of the seal lip 30 are always in contact with the outer circumferential surface of the cylindrical portion 12A of the oil draining member 12, and a small gap exists between the seal lip 30 and the outer circumferential surface of the cylindrical portion 12A of the oil draining member 12 in the portion 30C around the protrusions 36.

[0040] If the seal lip 30 contacts the outer circumferential surface of the cylindrical portion 12A over its entire circumference, when the pressure inside the rolling bearing 2 increases, the seal lip 30 may be pressed against the outer circumferential surface of the cylindrical portion 12A of the oil drain member 12, potentially generating heat due to friction. However, in this embodiment, air can circulate between the inside and outside of the rolling bearing 2 (the bearing interior side B and the atmosphere side A) through the small gap between the seal lip 30 and the outer circumferential surface of the cylindrical portion 12A of the oil drain member 12. Therefore, even if the pressure inside the rolling bearing 2 increases, the risk of heat generation can be reduced.

[0041] As described above, in this embodiment, each projection 36 has a parallel surface 36A parallel to the inner circumferential surface of the seal lip 30 and an inclined surface 36B whose height gradually decreases from the parallel surface 36A toward the inner circumferential surface of the seal lip 30. For this reason, it is easy to form the projections 36 such that they have a target height relative to the inner circumferential surface of the seal lip 30, as shown below.

[0042] A seal lip 30 with a projection 36 can be formed, for example, using a mold. Molding methods include, for example, injection molding or press molding. Figure 5 is a cross-sectional view showing a seal lip 30 formed by a mold. Immediately after molding, the seal lip 30 has trace portions 37 attached to it, which are traces of the material path within the mold for distributing the elastic material into the desired space. The trace portions 37 extending from the seal lip 30 also include portions extending from the projection 36. By cutting this molded product along a virtual surface C, the seal lip 30 (together with the projection 36) can be finished to remove the unnecessary trace portions 37.

[0043] If the parallel surface 36A of the projection 36 is not parallel to the inner circumferential surface of the seal lip 30, but is an extension of the inclined surface 36B, then if the cutting position during finishing deviates from the target position, the height h of the projection 36 relative to the inner circumferential surface of the seal lip 30 will not be the target height. Therefore, utmost care must be taken during the cutting process.

[0044] On the other hand, in this embodiment, since each protrusion 36 has a parallel surface 36A parallel to the inner peripheral surface of the seal lip 30, even if the cutting position is deviated from the target position, the height h of the protrusion 36 with respect to the inner peripheral surface of the seal lip 30 (the distance between the parallel surface 36A and the inner peripheral surface of the seal lip 30) has the target height. However, the parallel surface 36A of the protrusion 36 is not necessarily indispensable.

[0045] As shown in FIG. 6, it is preferable that minute irregularities are formed on the inner peripheral surface of the seal lip 30 including the protrusions 36. The minute irregularities can be irregularly formed by embossing. In this case, due to the minute irregularities on the inner peripheral surface of the seal lip 30, the frictional resistance of the seal lip 30 is reduced, and heat generation and torque are suppressed.

[0046] Further, due to the minute irregularities on the inner peripheral surface of the seal lip 30, a minute gap exists between the inner peripheral surface of the seal lip 30 and the outer peripheral surface of the cylindrical portion 12A of the oil cutoff member 12. Through the minute gap, air can flow between the inside and the outside of the rolling bearing 2 (bearing inner side B and atmosphere side A). Even when the pressure inside the rolling bearing 2 increases, the seal lip 30 is not strongly pressed against the outer peripheral surface of the cylindrical portion 12A of the oil cutoff member 12, and the risk of heat generation due to friction can be reduced.

[0047] The ten-point mean roughness Rz of the inner peripheral surface of the seal lip 30 having minute irregularities is preferably 15 μm or more and 30 μm or less. When the roughness of the inner peripheral surface of the seal lip 30 is less than 15 μm, the minute gap is small and the air flow is small. On the other hand, when the roughness of the inner peripheral surface of the seal lip 30 is greater than 30 μm, there is a risk that the lubricating oil leaks from the inside to the outside of the rolling bearing 2 through the minute gap. When the ten-point mean roughness Rz of the inner peripheral surface of the seal lip 30 is 15 μm or more and 30 μm or less, the sealing property of the lubricant by the seal lip 30 and the air flowability can be made compatible.

[0048] As shown in Fig. 1, in the inner seal member 20 according to this embodiment, the tip of the sub-lip 32 slidably contacts the outer peripheral surface of the cylindrical portion 12A of the oil cutoff member 12. However, the tip of the sub-lip 32 does not necessarily have to contact the oil cutoff member 12. In this case, an annular gap exists between the tip of the sub-lip 32 and the oil cutoff member 12. When the gap is small, the sub-lip 32 can prevent or reduce the intrusion of foreign matter from the atmosphere side A to the bearing inner side B.

[0049] Also, the tip of the side lip 34 slidably contacts the inner peripheral surface of the outer cylindrical portion 12C of the oil cutoff member 12. However, the tip of the side lip 34 does not necessarily have to contact the oil cutoff member 12. In this case, an annular gap exists between the tip of the side lip 34 and the oil cutoff member 12. When the gap is small, the side lip 34 can prevent or reduce the intrusion of foreign matter from the atmosphere side A to the bearing inner side B.

[0050] In the embodiment where the tip of the sub-lip 32 slidably contacts the outer peripheral surface of the cylindrical portion 12A of the oil cutoff member 12, a plurality of protrusions 38 are also formed on the inner peripheral surface of the sub-lip 32. These protrusions 38 always slidably contact the outer peripheral surface of the cylindrical portion 12A of the oil cutoff member 12. Therefore, on the inner peripheral surface of the sub-lip 32, the portion away from the protrusions 38 contacts the outer peripheral surface of the cylindrical portion 12A of the oil cutoff member 12, but a gap exists between the sub-lip 32 and the cylindrical portion 12A around the protrusions 38. For this reason, the sub-lip 32 has high sealing performance for lubricating oil, and even if the pressure inside the rolling bearing 2 decreases, it is not strongly attracted to the outer peripheral surface of the cylindrical portion 12A, and the risk of heat generation can be reduced.

[0051] Similar to the protrusions 36, three sets each having two protrusions 38 can be provided, and these three sets can be arranged at equal angular intervals, that is, at intervals of 120 degrees. However, the arrangement and number of the protrusions 38 are not limited to this embodiment.

[0052] In this embodiment, each projection 38 does not have a parallel surface corresponding to the parallel surface 36A of projection 36, but only has a surface inclined with respect to the inner circumferential surface of the sub-lip 32. However, each projection 38 may be positioned in contact with the tip edge of the sub-lip 32, and each projection 38 may have a parallel surface corresponding to the parallel surface 36A of projection 36. In this case, it is easier to form the projections 38 so that they have a target height with respect to the inner circumferential surface of the sub-lip 32.

[0053] Similar to the inner surface of the seal lip 30, it is preferable that minute irregularities are formed on the inner surface of the sub-lip 32 having the projection 38. These minute irregularities can be formed irregularly by a matte finish treatment. In this case, the minute irregularities on the inner surface of the sub-lip 32 reduce the frictional resistance of the sub-lip 32, thereby suppressing heat generation and torque. Furthermore, air can flow through the minute gaps caused by the minute irregularities, and even if the pressure inside the rolling bearing 2 decreases, the sub-lip 32 will not be attracted to the outer surface of the cylindrical portion 12A of the oil-cutting member 12, thus reducing the risk of heat generation due to friction.

[0054] Preferably, the ten-point average roughness Rz of the inner circumferential surface of the sub-lip 32, which has minute irregularities, is 15 μm or more and 30 μm or less. When the ten-point average roughness Rz of the inner circumferential surface of the sub-lip 32 is 15 μm or more and 30 μm or less, both the sealing performance of the lubricant by the sub-lip 32 and the airflow performance can be achieved.

[0055] In an embodiment where the tip of the side lip 34 slidably contacts the inner circumferential surface of the outer cylindrical portion 12C of the oil draining member 12, a plurality of protrusions 40 are also formed on the outer circumferential surface of the side lip 34. These protrusions 40 are always in slidable contact with the inner circumferential surface of the outer cylindrical portion 12C of the oil draining member 12. Therefore, on the outer circumferential surface of the side lip 34, the portion away from the protrusions 40 contacts the inner circumferential surface of the outer cylindrical portion 12C of the oil draining member 12, but a gap exists between the side lip 34 and the outer cylindrical portion 12C in the portion around the protrusions 40. For this reason, the side lip 34 having the protrusions 40 has high sealing performance for lubricating oil, and even if the pressure inside the rolling bearing 2 increases, it is not strongly pressed against the inner circumferential surface of the outer cylindrical portion 12C, thereby reducing the risk of overheating.

[0056] Similar to the projection 36, three sets of two projections 40 can be provided, and these three sets can be arranged at equal angular intervals, i.e., at intervals of 120 degrees. However, the arrangement and number of projections 40 are not limited to this embodiment.

[0057] In this embodiment, each projection 40 does not have a parallel surface corresponding to the parallel surface 36A of projection 36, but only has a surface inclined with respect to the outer circumferential surface of the side lip 34. However, each projection 40 may be positioned in contact with the leading edge of the side lip 34, and each projection 40 may have a parallel surface corresponding to the parallel surface 36A of projection 36. In this case, it is easier to form the projections 40 so that they have a target height with respect to the outer circumferential surface of the side lip 34.

[0058] Similar to the inner circumferential surface of the seal lip 30, it is preferable that minute irregularities are formed on the outer circumferential surface of the side lip 34 having the protrusions 40. These minute irregularities can be formed irregularly by a textured finish. In this case, the minute irregularities on the outer circumferential surface of the side lip 34 reduce the frictional resistance of the side lip 34, thereby suppressing heat generation and torque. Furthermore, air can flow through the minute gaps caused by the minute irregularities, and even if the pressure inside the rolling bearing 2 increases, the side lip 34 will not be pressed against the inner circumferential surface of the outer cylindrical portion 12C of the oil-cutting member 12, thereby reducing the risk of heat generation due to friction.

[0059] Preferably, the ten-point average roughness Rz of the outer circumferential surface of the side lip 34, which has minute irregularities, is 15 μm or more and 30 μm or less. When the ten-point average roughness Rz of the outer circumferential surface of the side lip 34 is 15 μm or more and 30 μm or less, both the sealing performance of the lubricant by the side lip 34 and the airflow performance can be achieved.

[0060] Second Embodiment

[0061] Figure 7 shows a sealing device 40 according to a second embodiment of the present invention. In the drawings from Figure 7 onward, the same reference numerals are used to indicate components that have already been described, and these components will not be described in detail.

[0062] The sealing device 40 is positioned between the relatively rotating inner ring 6 and outer ring 8, sealing the gap between the inner ring 6 and the outer ring 8. The sealing device 40 prevents or reduces the outflow of grease, i.e., lubricant, from inside the rolling bearing 2, and also prevents or reduces the inflow of foreign matter from the outside into the rolling bearing 2. In Figure 7, arrow D shows an example of the direction of foreign matter flow from the outside.

[0063] In Figure 7, only the left-side portion relative to the axle 4 is shown, but the sealing device 40 and the rolling bearing 2 have a rotationally symmetrical shape. The upper side of Figure 7 is the inside of the bearing B, and the lower side is the atmospheric side A. However, a sealing device similar to the sealing device 40 is also provided on the opposite side of the rolling bearing 2 from the sealing device 40.

[0064] The sealing device 40 comprises an annular inner sealing member 41 and an annular outer sealing member 50. The inner sealing member 41 is fixed to the inner ring 6. The outer sealing member 50 is fixed to the inner surface of the hole 8A of the outer ring 8, and the inner sealing member 41 is in slidable contact with the outer sealing member 50.

[0065] The inner seal member 41 is formed from a rigid material, such as metal. The inner seal member 41 comprises a sleeve 42, a flange 44, and an outer sleeve 46. The sleeve 42 is fixed to the inner ring 6. The fixing method may be, for example, a pressure fit. The flange 44 extends radially outward from the atmospheric end of the sleeve 42. The outer sleeve 46 extends axially from the outer edge of the flange 44 toward the bearing interior B of the inner seal member 41.

[0066] The outer sealing member 50 is positioned between the relatively rotating outer ring 8 and the inner sealing member 41, sealing the gap between the outer ring 8 and the inner sealing member 41. Therefore, the outer sealing member 50 can be considered a sealing device.

[0067] The outer sealing member (sealing device) 50 has a double structure comprising a rigid part 52 formed from a rigid material, such as metal, and an elastic part 54 formed from an elastic material, such as elastomer. The elastic part 54 is fixed to the rigid part 52, and the rigid part 52 reinforces the elastic part 54.

[0068] The rigid portion 52 has a cylindrical portion 55 fixed to the inner surface of the hole 8A of the outer ring 8, an annular portion 56, a plurality of axially protruding portions 57, and a plurality of inner extension portions 58.

[0069] The cylindrical portion 55 is fitted into the inner surface of the hole 8A of the outer ring 8 by interference fit. The end 55a of the cylindrical portion 55 on the bearing inner side B is formed as a hook that widens radially outward. A circumferential groove, or recess 8C, is formed in the hole 8A, and the end 55a of the cylindrical portion 55 is fitted into the recess 8C.

[0070] The annular portion 56 extends radially inward from the atmospheric-side end A of the cylindrical portion 55. The annular portion 56 extends in a plane perpendicular to the axial direction of the outer sealing member 50.

[0071] Multiple axial projections 57 protrude from the annular portion 56 toward the atmosphere A in the axial direction of the outer sealing member 50. As shown in Figure 8, the multiple axial projections 57 have a shape in which multiple locations of the annular portion 56 are bent at angular intervals in the circumferential direction. In addition, multiple locations of the annular portion 56 where the multiple axial projections 57 are not formed are continuous with multiple inner extensions 58 that extend radially inward from the annular portion 56. Preferably, the axial projections 57 and inner extensions 58 are arranged at equal angular intervals, but these angular intervals do not have to be equal. In this embodiment, eight axial projections 57 and eight inner extensions 58 are provided, but the number of axial projections 57 and the number of inner extensions 58 may be two or more, and are not limited to these numbers.

[0072] Returning to Figure 7, a recess 59 extending radially inward is formed on the radially outer surface of each axial projection 57. In this embodiment, the recess 59 is a through hole, but the recess 59 does not have to penetrate the axial projection 57.

[0073] The elastic portion 54 has an annular base portion 60 supported by the rigid portion 52, a seal lip (grease lip) 62, a dust lip (side lip) 64, a radial projection 66, and a cylindrical wall portion 68.

[0074] The base 60 of the elastic portion 54 is an annular portion located radially inward of the plurality of axially protruding portions 57 of the rigid portion 52, and is fixed to the plurality of inner extension portions 58 of the rigid portion 52. The entirety of the plurality of inner extension portions 58, which are intermittently arranged in the circumferential direction, are embedded in the circumferentially continuous annular base 60, and the inner extension portions 58 reinforce the base 60.

[0075] The seal lip 62 is a plate-shaped ring extending from the base 60 and slidably contacting the outer circumferential surface of the sleeve 42 of the inner seal member 41. The seal lip 62 primarily functions to prevent or reduce the leakage of lubricating oil from the bearing interior side B to the atmosphere side A. The seal lip 62 has a frustoconical annular base end portion 62a extending radially inward from the base 60 toward the atmosphere side A, and a frustoconical annular tip portion 62b extending obliquely from the base end portion 62a toward radially inward from the bearing interior side B. The tip of the tip portion 62b slidably contacts the outer circumferential surface of the sleeve 42 of the inner seal member 41 over its entire circumference. The thickness of the base end portion 62a is greater than the thickness of the tip portion 62b.

[0076] The dust lip 64 is a plate-shaped ring that extends from the base 60 and toward the side surface of the flange 44 of the inner seal member 41 toward the bearing interior side B. The dust lip 64 mainly has the function of preventing or reducing the intrusion of foreign matter from the atmospheric side A into the bearing interior side B. The dust lip 64 has a base end portion 64a that extends from the base 60 toward the atmospheric side A and radially inward, and a tip portion 64b that extends from the base end portion 64a toward the atmospheric side A and radially outward, with the tip portion 64b extending toward the side surface of the flange 44 of the inner seal member 41 toward the bearing interior side B. The thickness of the base end portion 64a is greater than the thickness of the tip portion 64b.

[0077] The radial projection 66 protrudes radially inward from the inner edge of the base portion 60. The radial projection 66 has a trapezoidal cross-section that is wider on the radially outer side and narrower on the inner side. The radial projection 66 does not come into contact with the inner seal member 41, and a small annular gap 69 is provided between the radial projection 66 and the sleeve 42 of the inner seal member 41. The gap 69 obstructs the flow of lubricating oil from the bearing interior side B to the atmosphere side A, and reduces the amount of lubricating oil that reaches the seal lip 62, thereby assisting the sealing performance of the seal lip 62.

[0078] The cylindrical wall portion 68 is a cylindrical part that extends from the outer edge of the base portion 60 toward the flange 44 of the inner sealing member 41 and is fixed to a plurality of axially projecting portions 57 of the rigid portion 52. The entirety of the plurality of axially projecting portions 57, which are intermittently arranged in the circumferential direction, are embedded in the circumferentially continuous cylindrical wall portion 68, and the axially projecting portions 57 reinforce the cylindrical wall portion 68.

[0079] The elastic portion 54 includes not only the inner extension portion 58 of the rigid portion 52, but also a part of the annular portion 56 and the entirety of the multiple axially protruding portions 57. Specifically, a part of the air-facing side A of the annular portion 56 is covered by a part 70 of the elastic portion 54, a part of the bearing-internal side B of the annular portion 56 is covered by a part 72 of the elastic portion 54, and the axially protruding portions 57 are covered by the cylindrical wall portion 68 of the elastic portion 54. However, the annular portion 56 does not necessarily have to be covered with elastic material.

[0080] Multiple axially protruding portions 57 and cylindrical wall portions 68 of the elastic portion 54, which are intermittently provided on the rigid portion 52 of the outer sealing member 50, extend toward the flange 44 of the inner sealing member 41. The cylindrical wall portions 68 do not come into contact with the flange 44, and an annular gap 74 is provided between the cylindrical wall portions 68 and the flange 44.

[0081] The outer sleeve 46 of the inner sealing member 41 is positioned outside the cylindrical wall portion 68. The cylindrical wall portion 68 does not come into contact with the outer sleeve 46, and an annular gap 76 is provided between the cylindrical wall portion 68 and the outer sleeve 46.

[0082] In this embodiment, the axially protruding portion 57 is covered by the cylindrical wall portion 68 of the elastic portion 54, thereby the elastic portion 54 closing the recess 59 formed in the axially protruding portion 57. In the portion of the cylindrical wall portion 68 of the elastic portion 54 that covers the radially outer surface of each axially protruding portion 57, the portion 72 that closes the recess 59 of the elastic portion 54 is recessed. During the manufacture of the sealing device 40, the material of the elastic portion 54 can shrink significantly near the recess 59, causing the portion 72 to be recessed. Alternatively, the recessing of the portion 72 may be performed after the manufacture of the sealing device 40.

[0083] Repairing the rolling bearing 2 necessitates replacing the sealing device 40. The removal procedure for the sealing device 40 will be explained with reference to Figure 9.

[0084] First, several jigs 80 are prepared. Each jig 80 has a long handle portion 80a and a tip portion 80b that is bent relative to the handle portion 80a. The worker grips the handle portion 80a.

[0085] Then, the tip 80b of each jig 80 is inserted into the recess 59 formed in the axially protruding portion 57 of the rigid portion 52 of the outer sealing member 50 of the sealing device 40, thereby capturing the recess 59 with the jig 80. In this embodiment, if the recess 59 is blocked by the elastic portion 54, that portion is compressed significantly by the tip 80b. That portion may be damaged.

[0086] In this state, the jig 80 applies a force F radially inward to the outer sealing member 50, compressing the elastic portion 54 and subsequently the rigid portion 52 of the outer sealing member 50 in the radial direction, thereby partially separating the cylindrical portion 55 of the rigid portion 52 of the outer sealing member 50 from the inner surface of the hole 8A of the outer ring 8.

[0087] Next, by pulling the jig 80, in which the tip portion 80b is inserted into the recess 59, with force S, the outer seal member 50 can be moved in the axial direction and removed from the hole 8A of the outer ring 8 of the rolling bearing 2. Once the annular portion 56 of the rigid portion 52 of the outer seal member 50 is partially separated from the inner surface of the hole 8A of the outer ring 8, it is easy to remove the outer seal member 50 from the hole 8A of the outer ring 8 of the rolling bearing 2 by utilizing the elastic deformation of the outer seal member 50. As the outer seal member 50 is removed, the flange 44 is pressed against the cylindrical wall portion 68 of the outer seal member 50, and the inner seal member 41 fixed to the inner ring 6 can also be removed together with the outer seal member 50. In this way, the sealing device 40 can be easily removed. However, it is not necessary to remove the outer seal member 50 and the inner seal member 41 at the same time; the inner seal member 41 may be pulled out of the inner ring 6 first, and then the outer seal member 50 may be pulled out of the outer ring 8.

[0088] This removal process uses multiple jigs 80, but the worker's hands may be used instead of the jigs 80. Even when multiple jigs 80 are used, the jigs 80 may be used only to apply a force S to the outer seal member 50 and remove the outer seal member 50 from the hole 8A of the outer ring 8. That is, the worker's hands or other jigs may be used to apply a force F radially inward to the outer seal member 50, thereby compressing the outer seal member 50 radially.

[0089] As shown in Figure 8, the recesses 59 into which the jig 80 is inserted are located at multiple points separated by angular intervals in the circumferential direction. Each recess 59 is closed by a portion 72 of the elastic part 54. It is desirable that the location of the recess 59 can be easily located in order to insert the jig 80 or the worker's hand into the recess 59.

[0090] Therefore, in this embodiment, as shown in Figures 7 and 9, a plurality of markers 82 are formed on a portion 70 of the elastic part 54 fixed to the atmospheric side A of the annular portion 56. These markers 82 are arranged at multiple positions that overlap the recess 59 in the radial direction. The worker can recognize the markers 82 visually or tactilely and easily insert the jig 80 or their hand into the recess 59 corresponding to the marker 82. In this embodiment, each marker 82 is a hemispherical projection, but the shape of the marker 82 is not limited to this, and it may be a projection of another shape, or a recess or mark. Alternatively, the marker 82 is not limited to a three-dimensional shape, and may be a colored marker or a marker with a pattern on a visually recognizable plane.

[0091] Similar to the projection 36 formed on the seal lip 30 in the first embodiment, a plurality of projections 84 are formed on the tip portion 62b of the seal lip 62 in this embodiment. These projections 84 are always in slidable contact with the outer circumferential surface of the sleeve 42 of the inner seal member 41. Therefore, on the inner circumferential surface of the tip portion 62b of the seal lip 62, the portion away from the projections 84 is in contact with the outer circumferential surface of the sleeve 42, but a gap exists between the tip portion 62b of the seal lip 62 and the sleeve 42 in the portion around the projections 84.

[0092] As described above, the seal lip 62 slidably contacts the outer circumferential surface of the sleeve 42, sealing the lubricating oil inside the rolling bearing 2. Therefore, the sealing performance of the lubricating oil is high. On the other hand, the multiple protrusions 84 formed on the inner circumferential surface of the seal lip 62 are always in contact with the outer circumferential surface of the sleeve 42, and a small gap exists between the seal lip 62 and the outer circumferential surface of the sleeve 42 in the area around the protrusions 84. Air can flow between the inside and outside of the rolling bearing 2 (inside the bearing B and the atmosphere A) through the small gap between the seal lip 62 and the outer circumferential surface of the sleeve 42. Therefore, even if the pressure inside the rolling bearing 2 increases, the risk of overheating can be reduced.

[0093] Similar to the projection 36 formed on the seal lip 30 in the first embodiment, preferably, each projection 84 has a parallel surface 84A parallel to the inner circumferential surface of the tip portion 62b of the seal lip 62, and an inclined surface 84B whose height gradually decreases from the parallel surface 84A toward the inner circumferential surface of the tip portion 62b of the seal lip 62. In this case, it is easy to form the projection 84 such that it has a target height relative to the inner circumferential surface of the seal lip 62.

[0094] Furthermore, similar to the seal lip 30 of the first embodiment, preferably, minute irregularities (not shown) are formed on the inner circumferential surface of the tip portion 62b of the seal lip 62 including the projection 84. Preferably, the ten-point average roughness Rz of the inner circumferential surface of the seal lip 62 having minute irregularities is 15 μm or more and 30 μm or less.

[0095] In this embodiment, the tip portion 64b of the dust lip 64 does not contact the flange 44 of the inner seal member 41, and an annular gap is provided between the tip portion 64b and the flange 44. However, the tip portion 64b of the dust lip 64 may contact the flange 44 of the inner seal member 41. In this case, preferably, a plurality of protrusions (not shown) are formed on the inner circumferential surface of the tip portion 64b of the dust lip 64, which are always in slidable contact with the flange 44. In this case, on the inner circumferential surface of the tip portion 64b of the dust lip 64, the portion away from the protrusions contacts the flange 44, but a small gap exists between the tip portion 64b of the dust lip 64 and the flange 44 in the portion around the protrusions. Air can circulate between the inside and outside of the rolling bearing 2 (inside the bearing B and the atmosphere A) through this small gap. Preferably, each projection has a parallel surface parallel to the inner circumferential surface of the tip portion 64b of the dust lip 64, and an inclined surface whose height gradually decreases from the parallel surface toward the inner circumferential surface of the tip portion 64b of the dust lip 64. Preferably, minute irregularities are formed on the inner circumferential surface of the tip portion 64b of the dust lip 64 including the projection. Preferably, the ten-point average roughness Rz of the inner circumferential surface of the seal lip 62 having minute irregularities is 15 μm or more and 30 μm or less.

[0096] Third Embodiment

[0097] Figure 10 shows a sealing device 90 according to a third embodiment of the present invention.

[0098] The sealing device 90 is positioned between the inner ring 6 and the outer ring 8, which rotate relative to each other, and seals the gap between the inner ring 6 and the outer ring 8. The sealing device 90 prevents or reduces the outflow of grease, i.e., lubricant, from inside the rolling bearing 2, and also prevents or reduces the inflow of foreign matter from the outside into the rolling bearing 2. In Figure 10, arrow D shows an example of the direction of foreign matter flow from the outside.

[0099] In Figure 10, only the left side of the axle 4 is shown, but the sealing device 90 and the rolling bearing 2 have a rotationally symmetrical shape. The upper side of Figure 10 is the inside of the bearing B, and the lower side is the atmospheric side A. However, a sealing device similar to the sealing device 90 is also provided on the opposite side of the rolling bearing 2 from the sealing device 90.

[0100] The sealing device 90 has four annular sealing members, namely an outer sealing member 16, an intermediate sealing member 18, an inner sealing member 91, and a slinger 110.

[0101] The outer sealing member 16 and the intermediate sealing member 18 in this embodiment are substantially the same as those in the first embodiment. However, the annular portion 16D of the outer sealing member 16 in this embodiment is inclined and has a frustoconical shape.

[0102] The slinger 110 is formed from a rigid material, such as metal. The slinger 110 comprises a sleeve 112, a flange 114, and an outer sleeve 116. The sleeve 112 is fixed to the inner ring 6. The fixing method may be, for example, an interference fit. The flange 114 extends radially outward from the atmospheric end of the sleeve 112. The outer sleeve 116 extends axially from the outer edge of the flange 114 toward the bearing interior B.

[0103] An annular gap 117 is provided between the outer sleeve 116 and the inner cylindrical portion 16E of the outer sealing member 16, and an annular gap 118 is provided between the end of the sleeve 112 on the bearing inner side B and the inner cylindrical portion 18C of the intermediate sealing member 18.

[0104] The inner sealing member 91 is positioned inside the outer sealing member 16 and the intermediate sealing member 18, and is located between the relatively rotating outer sealing member 16 and the slinger 110, sealing the gap between the outer sealing member 16 and the slinger 110. Therefore, the inner sealing member 91 can be considered a sealing device.

[0105] The inner sealing member (sealing device) 91 has a double structure comprising a rigid part 92 formed from a rigid material, such as metal, and an elastic part 93 formed from an elastic material, such as elastomer. The elastic part 93 is fixed to the rigid part 92, and the rigid part 92 reinforces the elastic part 93.

[0106] The inner sealing member 91 has a mounting cylindrical portion 94, an annular portion 95, a sealing lip (grease lip) 96, a secondary lip (dust lip) 97, and a side lip (dust lip) 98, which are fixed to the intermediate sealing member 18.

[0107] The mounting cylindrical portion 94 has a rigid portion 92 and an elastic portion 93, and is fixed to the inner circumferential surface of the outer cylindrical portion 18A of the intermediate sealing member 18 by interference fit.

[0108] The annular portion 95 has a rigid portion 92 and an elastic portion 93, and extends radially inward from the mounting cylindrical portion 94.

[0109] The elastic portion 93 has lips 96, 97, and 98.

[0110] The seal lip 96 is a frustoconical radial lip that extends diagonally inward from the inner end of the annular portion 95 toward the bearing interior side B. The seal lip 96 extends toward the outer circumferential surface of the sleeve 112 of the slinger 110, and the tip of the seal lip 96 slidably contacts the outer circumferential surface of the sleeve 112 over its entire circumference. The seal lip 96 primarily serves to prevent or reduce the leakage of lubricating oil from the bearing interior side B to the atmosphere side A.

[0111] The secondary lip 97 is a frustoconical radial lip that extends diagonally inward and toward the atmosphere side A from the inner end of the annular portion 95. The secondary lip 97 is positioned inside the outer sleeve 116 of the slinger 110 and extends toward the outer circumferential surface of the sleeve 112 of the slinger 110. In this embodiment, the tip of the secondary lip 97 is in slidable contact with the outer circumferential surface of the sleeve 112 of the slinger 110 over its entire circumference. The secondary lip 97 primarily has the function of preventing or reducing the intrusion of foreign matter from the atmosphere side A to the inside of the bearing B, and also has the function of preventing or reducing the leakage of lubricating oil from the inside of the bearing B to the atmosphere side A.

[0112] The side lip 98 is a frustoconical radial lip that extends diagonally outward from the annular portion 95 and toward the atmosphere side A. The side lip 98 is positioned inside the outer sleeve 116 of the slinger 110 and extends toward the inner circumferential surface of the outer sleeve 116 of the slinger 110. In this embodiment, the tip of the side lip 98 is in slidable contact with the inner circumferential surface of the outer sleeve 116 of the slinger 110 over its entire circumference. The side lip 98 primarily has the function of preventing or reducing the intrusion of foreign matter from the atmosphere side A to the inside of the bearing B, and also has the function of preventing or reducing the leakage of lubricating oil from the inside of the bearing B to the atmosphere side A.

[0113] Similar to the projection 36 formed on the seal lip 30 in the first embodiment, a plurality of projections 100 are formed on the inner circumferential surface of the seal lip 96 in this embodiment. These projections 100 are always in slidable contact with the outer circumferential surface of the sleeve 112 of the slinger 110. Therefore, on the inner circumferential surface of the seal lip 96, the portion away from the projections 100 is in contact with the outer circumferential surface of the sleeve 112, but a gap exists between the seal lip 96 and the sleeve 112 in the portion around the projections 100.

[0114] As described above, the seal lip 96 slidably contacts the outer circumferential surface of the sleeve 112, sealing the lubricating oil inside the rolling bearing 2. Therefore, the sealing performance of the lubricating oil is high. On the other hand, the multiple protrusions 100 formed on the inner circumferential surface of the seal lip 96 are always in contact with the outer circumferential surface of the sleeve 112, and a small gap exists between the seal lip 96 and the outer circumferential surface of the sleeve 112 in the area around the protrusions 100. Air can flow between the inside and outside of the rolling bearing 2 (inside the bearing B and the atmosphere A) through the small gap between the seal lip 96 and the outer circumferential surface of the sleeve 112. Therefore, even if the pressure inside the rolling bearing 2 increases, the risk of overheating can be reduced.

[0115] Similar to the projection 36 formed on the seal lip 30 in the first embodiment, preferably, each projection 100 has a parallel surface 100A parallel to the inner circumferential surface of the seal lip 96 and an inclined surface 100B whose height gradually decreases from the parallel surface 100A toward the inner circumferential surface of the seal lip 96. In this case, it is easy to form the projection 100 so that it has a target height relative to the inner circumferential surface of the seal lip 96.

[0116] Furthermore, similar to the seal lip 30 of the first embodiment, preferably, minute irregularities (not shown) are formed on the inner circumferential surface of the seal lip 96 including the projection 100. Preferably, the ten-point average roughness Rz of the inner circumferential surface of the seal lip 96 having minute irregularities is 15 μm or more and 30 μm or less.

[0117] In the inner sealing member 91 according to this embodiment, the tip of the sub-lip 97 slidably contacts the outer circumferential surface of the sleeve 112 of the slinger 110. However, the tip of the sub-lip 97 does not have to contact the slinger 110. In this case, an annular gap exists between the tip of the sub-lip 97 and the slinger 110, but if the gap is small, the sub-lip 97 can prevent or reduce the intrusion of foreign matter from the atmospheric side A to the bearing interior side B.

[0118] Furthermore, the tip of the side lip 98 is in slidable contact with the inner circumferential surface of the outer sleeve 116 of the slinger 110. However, the tip of the side lip 98 does not have to contact the slinger 110. In this case, an annular gap exists between the tip of the side lip 98 and the slinger 110, but if the gap is small, the side lip 98 can prevent or reduce the intrusion of foreign matter from the atmospheric side A to the bearing interior side B.

[0119] In an embodiment where the tip of the sub-lip 97 slidably contacts the outer circumferential surface of the sleeve 112 of the slinger 110, a plurality of protrusions 102 are also formed on the inner circumferential surface of the sub-lip 97. These protrusions 102 are always slidably in contact with the outer circumferential surface of the sleeve 112 of the slinger 110. Therefore, on the inner circumferential surface of the sub-lip 97, the portion away from the protrusions 102 contacts the outer circumferential surface of the sleeve 112 of the slinger 110, but a gap exists between the sub-lip 97 and the cylindrical portion 12A around the protrusions 102. As a result, the sub-lip 97 has high sealing performance for lubricating oil, and even if the pressure inside the rolling bearing 2 decreases, it is not strongly attracted to the outer circumferential surface of the sleeve 112, thereby reducing the risk of overheating.

[0120] In this embodiment, each projection 102 does not have a parallel surface corresponding to the parallel surface 100A of projection 100, but only has a surface inclined with respect to the inner circumferential surface of the sub-lip 97. However, each projection 102 may be positioned in contact with the tip edge of the sub-lip 97, and each projection 102 may be provided with a parallel surface corresponding to the parallel surface 100A of projection 100. In this case, it is easier to form the projections 102 so that they have a target height with respect to the inner circumferential surface of the sub-lip 97.

[0121] Similar to the inner surface of the seal lip 96, it is preferable that minute irregularities are formed on the inner surface of the sub-lip 97 having the projection 102. The ten-point average roughness Rz of the inner surface of the sub-lip 97 having minute irregularities is preferably 15 μm or more and 30 μm or less.

[0122] In an embodiment where the tip of the side lip 98 slidably contacts the inner circumferential surface of the outer sleeve 116 of the slinger 110, a plurality of protrusions 104 are also formed on the outer circumferential surface of the side lip 98. These protrusions 104 are always in slidable contact with the inner circumferential surface of the outer sleeve 116 of the slinger 110. Therefore, on the outer circumferential surface of the side lip 98, the portion away from the protrusions 104 contacts the inner circumferential surface of the outer sleeve 116 of the slinger 110, but a gap exists between the side lip 98 and the outer sleeve 116 in the portion around the protrusions 104. As a result, the side lip 98 has high sealing performance for lubricating oil, and even if the pressure inside the rolling bearing 2 increases, it is not strongly pressed against the inner circumferential surface of the outer sleeve 116, thereby reducing the risk of overheating.

[0123] In this embodiment, each projection 104 does not have a parallel surface corresponding to the parallel surface 36A of projection 36, but only has a surface inclined with respect to the outer circumferential surface of the side lip 98. However, each projection 104 may be positioned in contact with the leading edge of the side lip 98, and each projection 104 may have a parallel surface corresponding to the parallel surface 36A of projection 36. In this case, it is easier to form the projections 104 so that they have a target height with respect to the outer circumferential surface of the side lip 98.

[0124] Similar to the inner circumferential surface of the seal lip 96, it is preferable that minute irregularities are formed on the outer circumferential surface of the side lip 98 having the projection 104. The ten-point average roughness Rz of the outer circumferential surface of the side lip 98 having minute irregularities is preferably 15 μm or more and 30 μm or less.

[0125] Other Modifications Although embodiments of the present invention have been described above, the above description is not intended to limit the present invention, and various modifications, including the deletion, addition, and substitution of components, are conceivable within the technical scope of the present invention.

[0126] For example, the shape and number of lips on the sealing device are not limited to those described above.

[0127] In the above embodiment, the inner ring 6 and oil drain member 12, which are inner members, are rotating members, and the outer ring 8, which is an outer member, is a stationary member. However, the present invention is not limited to the above embodiment and can be applied to sealing a plurality of members that rotate relative to each other. For example, the inner member may be stationary and the outer member may rotate, or all of these members may rotate.

[0128] Aspects of the present invention are also described in the numbered clauses below.

[0129] Clause 1. A sealing device disposed between a relatively rotating inner member and an outer member of a rolling bearing, for sealing the gap between the inner member and the outer member, comprising: an annular rigid part formed of a rigid material fixed inside a hole in the outer member; and an elastic part formed of an elastic material fixed to the rigid part, wherein the elastic part has a frustoconical annular sealing lip that slidably contacts the inner member or a member fixed to the inner member; a plurality of protrusions are formed on the inner circumferential surface of the sealing lip that are always slidably in contact with the inner member or a member fixed to the inner member; and a gap exists between the sealing lip and the inner member or a member fixed to the inner member in the portion surrounding the protrusions.

[0130] Clause 2. The sealing device according to Clause 1, characterized in that each of the projections has a parallel surface parallel to the inner circumferential surface of the seal lip and an inclined surface that is connected to the parallel surface and whose height gradually decreases from the parallel surface toward the inner circumferential surface.

[0131] In this case, when a seal lip with a protrusion is formed, for example, using a mold, and then the seal lip (along with the protrusion) is finished by cutting, the protrusion has a parallel surface parallel to the inner circumferential surface of the seal lip. Therefore, even if the cutting position deviates from the target position, the height of the protrusion (the distance between the parallel surface and the inner circumferential surface) will be the target height.

[0132] Clause 3. The sealing device according to Clause 1 or 2, characterized in that the inner circumferential surface of the seal lip has irregularities formed thereon.

[0133] In this case, the minute irregularities on the inner surface of the seal lip reduce the frictional resistance of the seal lip, thereby suppressing heat generation and torque. Furthermore, the minute irregularities on the inner surface of the seal lip create a minute gap between the seal lip and the inner member or a member fixed to the inner member. Through this minute gap, air can circulate between the inside and outside of the bearing, and even if the pressure inside the bearing increases or decreases, the risk of the seal lip and / or other lips being pressed against or attracted to the inner member or a member fixed to the inner member, thereby reducing the risk of heat generation due to friction.

[0134] Clause 4. The sealing device according to Clause 3, characterized in that the ten-point average roughness Rz of the inner circumferential surface is 15 μm or more and 30 μm or less.

[0135] In this case, the roughness of the inner surface due to minute irregularities is appropriate, allowing for both sealing of the lubricant by the seal lip and airflow.

[0136] Clause 5. The sealing device according to any one of Clauses 1 to 4, characterized in that the elastic portion has a frustoconical annular dust lip that slidably contacts the inner member or a member fixed to the inner member, and the inner circumferential surface of the dust lip has irregularities formed thereon.

[0137] In this case, the minute irregularities on the inner surface of the dust lip reduce the frictional resistance of the dust lip, suppressing heat generation and torque. Furthermore, the minute irregularities on the inner surface of the dust lip create a tiny gap between the dust lip and the inner member or the member fixed to the inner member. Through this tiny gap, air can circulate between the inside and outside of the bearing, and even if the pressure inside the bearing decreases, the risk of the dust lip being attracted to the inner member or the member fixed to the inner member and generating heat due to friction can be reduced.

[0138] Clause 6. The sealing device according to Clause 5, characterized in that the ten-point average roughness Rz of the inner surface of the dust lip is 15 μm or more and 30 μm or less.

[0139] In this case, the roughness of the inner surface due to minute irregularities is appropriate, allowing for both sealing of the lubricant by the dust lip and airflow.

[0140] 1 Sealing device 2 Rolling bearing 4 Axle 6 Inner ring (inner member) 8 Outer ring (outer member) 8A Hole 12 Oil drain member (inner member) 16 Outer seal member 18 Intermediate seal member 20 Inner seal member 20 Inner seal member (sealing device) 22 Rigid part 24 Elastic part 26 Mounting cylindrical part 28 Annular part 30 Seal lip (grease lip) 32 Sub-lip (dust lip) 34 Side lip (dust lip) 36 Projection 36A Parallel surface 36B Inclined surface 38 Projection 40 Sealing device 41 Inner seal member 50 Outer seal member (sealing device) 52 Rigid part 54 Elastic part 55 Cylindrical part 56 Annular part 62 Seal lip (grease lip) 64 Dust lip (side lip) 84 Projection 84A Parallel surface 84B Inclined surface 90 Sealing device 91 Inner sealing member (sealing device) 92 Rigid part 93 Elastic part 94 Mounting cylindrical part 95 Annular part 96 Seal lip (grease lip) 97 Sub-lip (dust lip) 98 Side lip (dust lip) 100 Projection 100A Parallel surface 100B Inclined surface 102 Projection 104 Projection 110 Slinger

Claims

DEPCT641. A sealing device is placed between the inner and outer parts of a ball bearing that rotate relative to each other to seal the gap between the inner and outer parts. The sealing device consists of: a rigid, ring-shaped part that is clamped to the inside of the bore of the outer part; the rigid part is made of rigid material; and a flexible part that is clamped to the rigid part; the flexible part is made of flexible material. The flexible part consists of a sealing edge shaped like a truncated conical ring that is in sliding contact with the inner part or the part clamped to the inner part. Multiple bumps are created on the inner perimeter surface of the sealing edge. The bumps are always in sliding contact with the inner part or the part clamped to the inner part, and a distance is provided between the sealing edge and the inner part or the part clamped to the inner part in the vicinity of the bumps.The sealing device under claim 1, in which each of the nodes consists of a parallel surface parallel to the inner surface of the seal edge and an inclined surface continuing from the parallel surface, the inclined surface having a height reduction of 3 from the parallel surface to the inner surface. Sealing device according to claim 1 or 2, where convex and concave sections are created on the inner periphery surface of the seal edge.

4. Sealing device according to claim 3, where the ten-point height of the irregularity Rz of the inner periphery surface is equal to or greater than 15 micrometers and equal to or less than 30 micrometers.

5. Sealing device according to any of claims 1 to 4, where the elastic part consists of a dust edge shaped as a truncated conical ring that is in sliding contact with the inner part or is bonded to the inner part, where convex and concave sections are created on the inner periphery surface of the dust edge.

6. Sealing device according to claim 5, where the ten-point height of the irregularity Rz of the inner periphery surface of the dust edge is equal to or greater than 15 micrometers and equal to or less than 30 micrometers.

Images