SEALED ROLLING BEARING

Abstract

A sealed rolling bearing is provided which includes slingers, and seal members disposed between the inner ring and the outer ring, and sealing the rolling element installation area. The radially inner and outer portions of each slinger are bent inwardly such that a labyrinth portion is defined between the radially outer bent portion of the slinger and the radially inner surface of the outer ring, the labyrinth portion having a path length, in the axial direction of the bearing, longer than the material thickness of the slinger.

Claims

1. A sealed rolling bearing comprising: two seal members disposed between an inner ring and an outer ring, each on either side of a rolling element installation area of the bearing, so as to seal the rolling element installation area, and two slingers each disposed outside of a respective one of the two seal members, and sized to lie within a width range of the bearing, the slingers being supported by the inner ring, and preventing, e.g., external splashed muddy water from entering the bearing, wherein each of the slingers includes: a radially inner bent portion formed by inwardly bending a radially inner side of the slinger, and press-fitted to an outer periphery of the inner ring; and a radially outer bent portion formed by inwardly bending a radially outer side of the slinger such that a labyrinth portion is defined between the radially outer bent portion and a radially inner surface of the outer ring, the labyrinth portion having a path length, in an axial direction of the bearing, longer than a material thickness of the slinger.

2. The sealed rolling bearing according to claim 1, wherein the seal members are rubber seals each reinforced by a metal core, and including at least one side lip disposed on an outer side surface of the rubber seal, and protruding in the axial direction of the bearing, the at least one side lip having a distal end located inwardly of the radially outer bent portion of the slinger such that a labyrinth portion is defined between the at least one side lip and an inner side surface of a body of the slinger.

3. The sealed rolling bearing according to claim 2, wherein the at least one side lip of each of the seal members includes demolding tapers, the demolding tapers being such that a radially outer surface and a radially inner surface of the at least one side lip are inclined in opposite directions to each other, relative to respective reference lines parallel to a center axis of the bearing.

4. The sealed rolling bearing according to claim 2, wherein the at least one side lip of each of the seal members comprises a plurality of side lips radially displaced from each other.

5. The sealed rolling bearing according to claim 1, wherein the slingers are formed by pressing.

6. The sealed rolling bearing according to claim 1, wherein the slingers are formed of a cold-rolled material.

7. The sealed rolling bearing according to claim 3, wherein the at least one side lip of each of the seal members comprises a plurality of side lips radially displaced from each other.

8. The sealed rolling bearing according to claim 2, wherein the slingers are formed by pressing.

9. The sealed rolling bearing according to claim 3, wherein the slingers are formed by pressing.

10. The sealed rolling bearing according to claim 4, wherein the slingers are formed by pressing.

11. The sealed rolling bearing according to claim 7, wherein the slingers are formed by pressing.

12. The sealed rolling bearing according to claim 2, wherein the slingers are formed of a cold-rolled material.

13. The sealed rolling bearing according to claim 3, wherein the slingers are formed of a cold-rolled material.

14. The sealed rolling bearing according to claim 4, wherein the slingers are formed of a cold-rolled material.

15. The sealed rolling bearing according to claim 5, wherein the slingers are formed of a cold-rolled material.

16. The sealed rolling bearing according to claim 7, wherein the slingers are formed of a cold-rolled material.

17. The sealed rolling bearing according to claim 8, wherein the slingers are formed of a cold-rolled material.

18. The sealed rolling bearing according to claim 9, wherein the slingers are formed of a cold-rolled material.

19. The sealed rolling bearing according to claim 10, wherein the slingers are formed of a cold-rolled material.

20. The sealed rolling bearing according to claim 11, wherein the slingers are formed of a cold-rolled material.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0029] FIG. 1 is a sectional view of a portion of a sealed rolling bearing according to the present invention.

[0030] FIG. 2 is an enlarged sectional view illustrating the positional relationship between side lips on each seal member and a slinger in the sealed rolling bearing of FIG. 1.

BEST MODE FOR CARRYING OUT THE INVENTION

[0031] A sealed rolling bearing embodying the present invention is described below with reference to FIGS. 1 and 2.

[0032] As illustrated in FIG. 1, the sealed rolling bearing 1 shown is a deep groove ball bearing of which both sides are sealed, and which is constituted by the combination of an inner ring 2; an outer ring 3; rolling elements 4 disposed between the inner and outer rings; a cage 5 retaining the rolling elements 4; two seal members 6; and two slingers 7.

[0033] The two seal members 6 are disposed each on either side of a rolling element installation area 8 between the inner ring 2 and the outer ring 3. The seal members 6 shown are rubber seals each including a metal core 6 for reinforcement, and mounted to the outer ring 3, which is rotatable. Circumferentially continuously extending side lips 6b protrude from the outer side surface of the rubber seal, in the axial direction of the bearing.

[0034] While the seal members 6 shown each has a plurality of side lips 6b radially displaced from each other, the number of the side lips 6b on the seal member is not particularly limited.

[0035] The slingers 7 are disposed outside of the respective seal members 6. The slingers 7 shown are formed by pressing a cold-rolled material, and each includes a body 7a having a flat plate shape. The radially inner and outer sides of the slinger 7 are inwardly bent, respectively, from the inner and outer edges of the body 7a, to extend toward the rolling element installation area 8, thus forming a radially inner bent portion 7b and a radially outer bent portion 7c, respectively.

[0036] The radially inner bent portion 7b and the radially outer bent portion 7c are straight portions having a circular annular shape, and extending parallel to the center axis of the bearing. Each slinger 7 is retained by the inner ring 2, which is fixed, with the radially inner bent portion 7b press-fitted to the outer periphery of the inner ring 2.

[0037] On the other hand, the radially outer bent portion 7c is located as close as possible to the radially inner surface of the outer ring 3, so as to define a labyrinth portion 9 whose path length in the axial direction of the bearing is longer than the material thickness t of the slinger 7 (see FIG. 2), between the radially inner surface of the outer ring 3 and the radially outer surface of the radially outer bent portion 7c.

[0038] Further, the distal end of the radially outer bent portion 7c is located as close as possible to a respective one of two annular protrusions 3a formed on the radially inner surface of the outer ring 3, so as to define a labyrinth portion 10 having a path area smaller than that of the labyrinth portion 9, between the annular protrusion 3a and the distal end of the radially outer bent portion 7c.

[0039] The annular protrusions 3a are formed for the purpose of defining, in the radially inner periphery of the outer ring 3, seal fitting grooves 3b for supporting the proximal ends of the respective seal members 6.

[0040] The side lips 6b of each seal member 6 each have its distal edge portion which has dimension B (see FIG. 2) located inwardly of the radially outer bent portion 7c of the slinger 7, thereby defining labyrinth portions 11 between the body 7a of the slinger 7 and the distal edges of the respective side lips 6b, too.

[0041] By making the distal edge portions of the side lips 6b located inwardly of the radially outer bent portion 7c of the slinger 7, the seal lips 6b and the radially outer bent portion 7c overlap with each other by dimension B. This causes meandering of the path through which e.g., muddy water could enter from outside (i.e. the path extending from the labyrinth portion 10 to the portion of a main lip 6c of each seal member 6 in sliding contact with the inner ring 2). The meandering shape increases the path length of the entry path, and also complicates the flow of, e.g., muddy water entering the entry path.

[0042] Also, the labyrinth portions 11 between the body 7a of each slinger 7 and the respective side lips 6a add to the number of entry hindering portions, thus further improving sealing performance.

[0043] The path widths C of the labyrinth portions 11 in FIG. 2 are set to C=(A−B), where A is the dimension of the radially outer bent portion 7c of the slinger 7 in the axial direction of the bearing. The path width C of the labyrinth portion 11 are exaggeratedly shown. In order to reduce a rise in the rotation torque caused by the contact of the side lips 6b of each seal member 6 with the body 7a of the slinger, the path widths C are set to C 20 in view of gaps inside of the bearing, and assembling errors, thereby preventing the side lips 6b from coming into contact with the body 7a.

[0044] Each side lip 6b of each seal member 6 is preferably provided with demolding tapers a and 8 as illustrated in FIG. 2. The demolding tapers a and 8 are, respectively, the inclination angle of the radially outer surface of the side lip 6b relative to a reference line L1 parallel to the center axis of the bearing, and the inclination angle of the radially inner surface of the side lip 6b relative to a reference line L2 parallel to the center axis of the bearing. The demolding tapers a and B are such that the radially outer and inner surfaces of the side lip 6b are inclined in opposite directions to each other.

[0045] In order to reduce the speed at which, e.g., muddy water flowing down onto the radially outer surface of the side lip flows down on this surface, the inclination angle (taper α) of the radially outer surface is preferably smaller than the inclination angle (taper β) of the radially inner surface. The taper α is preferably 5 degrees or less.

[0046] The taper β is preferably set to 15 degrees or more and 20 degrees or less. By setting the taper β within this range, e.g., muddy water flowing on the radially outers surface of the side lip 6b and reaching the distal end thereof flows the root side of the side lip 6b along the radially inner surface thereof, thus reducing the amount of muddy water dripping down directly from the distal end of the side lip 6b. In addition, by setting the taper β at such a large value, muddy water that has once entered the space between the seal member 6 and the slinger 7 can be discharged easily by a centrifugal force.

[0047] By providing the demolding tapers, the seal members 6, which are rubber seals, can be smoothly removed from the mold after being formed by injection molding, and thus can be easily manufactured.

[0048] As in the shown example, a plurality of side lips 6b are preferably disposed on each seal member 6, or a rubber seal, so as to be radially displaced from each other.

[0049] The larger the number of the side lips 6, the larger the number of the entry hindering portions, thus improving sealing performance more effectively.

[0050] While the seal members 6 shown are rubber seals, shields made of hard resin or metal which are used in shielded bearings may be used instead, as the seal members 6.

DESCRIPTION OF REFERENCE NUMERALS

[0051] 1: Sealed rolling bearing [0052] 2: Inner ring [0053] 3: Outer ring [0054] 3a: Annular protrusion [0055] 3b: Seal fitting groove [0056] 4: Rolling element [0057] 5: Cage [0058] 6: Seal member [0059] 6a: Metal core [0060] 6b: Side lip [0061] 6c: Main lip [0062] 7: Slinger [0063] 7a: Body [0064] 7b: Radially inner bent portion [0065] 7c: Radially outer bent portion [0066] 8: Rolling element installation area [0067] 9, 10, 11: Labyrinth portion [0068] A: Dimension, in the axial direction of the bearing, of the radially outer bent portion of the slinger [0069] B: Dimension of the distal end portion of the side lip that is located inwardly of the radially outer bent portion of the slinger [0070] C: Path width of the labyrinth portion between the distal end of the side lip and the body of the slinger [0071] t: Material thickness t of the slinger [0072] α, β: Demolding taper [0073] L1, L2: Reference line of the demolding taper