Rolling bearings

Abstract

To provide a rolling bearing that offers high dustproof, waterproof, and sealing performance, and minimizes the reduction in rotational performance due to friction with the inner ring, particularly a rolling bearing suitable for insert bearings. [Solution] The rolling bearing 1 has an inner ring 2 and an outer ring 3, and a plurality of rolling elements 4 interposed between the inner ring 2 and the outer ring 3, and is equipped with a seal structure 5 that seals the annular space S1 formed between the inner ring 2 and the outer ring 3. The seal structure 5 is composed of a first seal member 7 that seals the axial end of the annular space S1, and a second seal member 8 having a slinger 9 arranged axially outside the first seal member 7. The first seal member 7 is mounted on the inner circumferential surface of the outer ring 3 and has first and second lip portions 11b, 11c that contact the outer circumferential surface of the inner ring 2, and a third lip portion 11d that contacts the inner surface of the slinger 9, and the second seal member 8 is provided at the outer circumferential end of the slinger 9 and has a fourth lip portion 12a that contacts the axial end of the outer ring 3.

Description

Technical Field

[0001] This invention relates to a rolling bearing, and more particularly to a seal structure of a rolling bearing applied to an insert bearing.

Background Art

[0002] Conventionally, in a rolling bearing, there is known one provided with a seal structure for preventing the intrusion of dust, water, etc. into the bearing. The seal structure of this type of rolling bearing is generally composed of a seal material attached to the outer ring of the bearing and a slinger attached to the outer periphery of the inner ring of the bearing. However, in a rolling bearing used in a place strongly affected by dust, water, etc. (for example, a rolling bearing applied to an insert bearing), a seal structure with higher dust-proof, waterproof, and sealing performance is desired compared to a general rolling bearing.

[0003] FIG. 4 shows an example of a type of rolling bearing in which dust-proof, waterproof, and sealing performance is improved for use in an insert bearing (see, for example, Patent Document 1). The illustrated rolling bearing a includes a plurality of rolling elements d, d,... between an inner ring b and an outer ring c, and as a seal structure for sealing the annular space e between the inner and outer rings, an annular shield f whose radial end is attached to the outer ring c, and a seal material g having three seal lips h whose tips contact the outer peripheral surface of the inner ring b. The annular space e is configured to be sealed by these shield f and the three seal lips h.

[0004] In FIG. 4, reference numeral i indicates a lubricant supply passage to the annular space e, and reference numeral j indicates a bearing housing of the insert bearing. Further, reference numeral k indicates a fixing screw for fixing the inner ring b to the rotating body l.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

[0006] However, conventional sealing structures have the following problems, and improvements have been desired.

[0007] The seal structure shown in Figure 4 aims to improve the dustproof, waterproof, and sealing performance of the annular space e by increasing the number of seal lips h. However, simply increasing the number of seal lips h does not completely prevent dust, water, etc. from entering the inside of the bearing.

[0008] Furthermore, since the seal lip h is in physical contact with the outer surface of the inner ring b, increasing the number of seal lip h increases the frictional resistance with the inner ring b. This leads to problems such as increased frictional resistance and heat generation due to friction compared to a typical seal structure, which negatively affects rotational performance.

[0009] This invention was made in view of the above problems, and its purpose is to provide a rolling bearing that has high dustproof, waterproof, and sealing performance, and less reduction in rotational performance due to friction with the inner ring, and in particular a rolling bearing suitable for insert bearings. [Means for solving the problem]

[0010] To achieve the above objective, the rolling bearing according to the present invention comprises an inner ring and an outer ring, and a plurality of rolling elements interposed between the inner ring and the outer ring, and is equipped with a seal structure that seals the annular space formed between the inner ring and the outer ring, wherein the seal structure comprises a first seal member that seals the axial end of the annular space and a second seal member having a slinger positioned axially outside the first seal member, and the first seal member is mounted in a mounting groove formed at the axial end of the inner circumferential surface of the outer ring, and has first and second lip portions that contact the outer circumferential surface of the inner ring, and a third lip portion that contacts the inner surface of the slinger The second sealing member is provided at the outer peripheral end of the slinger and has a fourth lip portion made of an elastic body that contacts the axial end of the outer ring. The first sealing member is composed of an annular metal core and an elastic member made of an elastic body integrally molded with the metal core. The elastic member has a top portion that covers the outer peripheral end of the metal core and the first, second, and third lip portions. When mounted on the outer ring, the top portion is inserted into a fitting groove formed in the mounting groove, the tips of the first and second lip portions contact the outer peripheral surface of the inner ring, and the tip of the third lip portion contacts the inner surface of the slinger.

[0011] In this rolling bearing, the axial end of the annular space formed between the inner and outer rings is sealed by a first seal member and a second seal member. The first seal member is mounted on the inner circumferential surface of the outer ring, so that its first and second lip portions contact the outer circumferential surface of the inner ring, sealing the annular space between the inner and outer rings. The second seal member is mounted with a slinger on the axially outside of the first seal member, so that its fourth lip portion contacts the axial end of the outer ring. At this time, the third lip portion of the first seal member contacts the inner surface of the slinger, so that an annular sealed space is formed between the first seal member and the second seal member, and this sealed space is sealed by the second seal member. In this way, in this rolling bearing, the annular space containing the rolling elements is double-sealed by the first seal member and the second seal member, providing a rolling bearing with high dustproof, waterproof, and sealing performance.

[0012] Furthermore, in a preferred embodiment of the present invention, the first lip portion extends axially inward from the inner circumferential end of the metal core material and contacts the outer circumferential surface of the inner ring, and the second lip portion extends axially outward from the inner circumferential end of the metal core material and contacts the outer circumferential surface of the inner ring.

[0013] Furthermore, in another preferred embodiment of the present invention, a lubricant is filled and sealed within the annular space sealed by the first sealing member.

[0014] Furthermore, in another preferred embodiment of the present invention, a lubricant is filled and sealed within the sealed space formed between the first sealing member and the second sealing member. [Effects of the Invention]

[0015] According to this invention, the axial end of the annular space formed between the inner and outer rings of the bearing is double-sealed by the first seal member and the second seal member, thereby providing a rolling bearing with high dustproof, waterproof, and sealing performance. In particular, the first seal member uses three lip portions, from the first to the third, to form a sealing structure, resulting in a high sealing effect.

[0016] Furthermore, with respect to the first sealing member, the first lip portion is extended axially inward to contact the inner ring, and the second lip portion is extended axially outward to contact the inner ring. As a result, the first lip portion effectively prevents leakage of lubricant for the rolling elements, while the second lip portion effectively prevents the intrusion of dust and other particles from the outside.

[0017] Furthermore, according to this invention, a high sealing effect can be obtained for the annular space containing the rolling elements, so that lubricant for the rolling elements can be filled and sealed within the annular space. As a result, the lubricant supply passage communicating with the annular space, which was provided in conventional rolling bearings, can be eliminated, making it possible to provide a rolling bearing with a simple structure that requires less maintenance.

[0018] Furthermore, by filling and enclosing a lubricant in the sealed space formed between the first seal member and the second seal member, the effect of preventing the intrusion of dust, water, etc. from the outside can be enhanced.

Brief Description of the Drawings

[0019] [Figure 1] It is a cross-sectional view showing an example of the rolling bearing according to the present invention. [Figure 2] It is an enlarged cross-sectional view showing an example of the first seal member of the rolling bearing. [Figure 3] It is an enlarged cross-sectional view showing an example of the second seal member of the rolling bearing. [Figure 4] It is a cross-sectional view showing an example of a conventional rolling bearing.

Embodiments for Carrying Out the Invention

[0020] Hereinafter, embodiments of the present invention will be described in detail based on the drawings. Fig. 1 shows an example of the rolling bearing 1 according to the present invention.The illustrated rolling bearing 1 is a deep groove ball bearing applied to an insert bearing, and mainly includes an inner ring 2 and an outer ring 3, a plurality of rolling elements 4 interposed between these inner ring 2 and outer ring 3, and a seal structure 5 that seals the annular space S1 formed between the inner ring 2 and the outer ring 3.

[0021] The inner ring 2 and the outer ring 3 are annular metal members arranged coaxially, and arc grooves 2a and 3a that constitute the raceway surfaces of the rolling elements 4 are formed over the entire circumferential length on the outer peripheral surface of the inner ring 2 and the inner peripheral surface of the outer ring 3, respectively.The rolling elements 4 are composed of spheres (balls), and a plurality of rolling elements 4 are arranged at regular intervals in the circumferential direction by a cage 6.

[0022] Further, on the inner peripheral surface of the outer ring 3, a mounting groove portion 3b for mounting a first seal member 7 described later is formed. The mounting groove portion 3b is formed by grooving the axial end portion of the inner peripheral surface of the outer ring 3 into a substantially L shape, and a fitting groove 3c for mounting the outer peripheral end portion of the first seal member 7 described later is formed over the entire circumferential length in the mounting groove portion 3b. Here, the axial direction means the axial direction of the rotating shaft A (see FIG. 1) to which the rolling bearing 1 is mounted, and the same shall apply in the following description.

[0023] In the figure, reference numeral 100 indicates the bearing housing of the insert bearing, and the rolling bearing 1 is mounted inside this bearing housing 100. In the illustrated example, a spherical inner diameter surface 100a that engages with the outer peripheral surface of the outer ring 3 is formed on the inner peripheral surface of the bearing housing 100, and the rolling bearing 1 is mounted in the bearing housing 100 by fitting the outer ring 3 of the rolling bearing 1 into the spherical inner diameter surface 100a. Also, in the figure, reference numeral 101 indicates a mounting bolt for mounting the inner ring 2 of the rolling bearing 1 to the rotating shaft A.

[0024] The seal structure 5 is composed of a first seal member 7 that seals the axial end portion of the annular space S1, and a second seal member 8 having a slinger 9 disposed axially outside the first seal member 7. The first seal member 7 and the second seal member 8 are arranged symmetrically with respect to the axial both ends of the annular space S1 as shown in FIG. 1. Therefore, in the following description, the structure of one of the axial both ends will be described, and the description of the other will be omitted.

[0025] The first seal member 7 is an annular member mounted in the mounting groove portion 3b formed on the inner peripheral surface of the outer ring 3, and is composed of an annular metal core member 10 and an elastic member 11 integrally formed with the metal core member 10 (see FIG. 2).

[0026] The metal core member 10 is composed of an annular metal plate, and as shown in FIG. 2, in order from the outer peripheral side, it has a head portion 10a bent into a substantially U shape, a standing plate portion 10b extending vertically from the head portion 10a, a first inclined portion 10c extending axially outward from the standing plate portion 10b, and a second inclined portion 10d extending axially inward from the first inclined portion 10c.

[0027] The elastic member 11 is made of an elastic material such as rubber. In this embodiment, the elastic member 11 is integrally molded with the metal core material 10 by vulcanization molding of the rubber material.

[0028] Here, as shown in Figure 2, the elastic member 11 is arranged to cover the metal core material 10, and has at least a top portion 11a that covers the top portion 10a of the metal core material 10, as well as three lip portions 11b to 11d that protrude from the metal core material 10.

[0029] As shown in the figure, the top portion 11a of the elastic member 11 has a substantially rectangular cross-section at its top portion (outer peripheral end) so that it can fit into the fitting groove 3c of the outer ring 3 described above, and is inserted into the fitting groove 3c when the first sealing member 7 is press-fitted and attached to the outer ring 3.

[0030] The three lip portions consist of a first lip portion 11b, a second lip portion 11c, and a third lip portion 11d. The first lip portion 11b is a sealing lip that contacts the outer circumferential surface of the inner ring 2, and extends diagonally inward in the axial direction from the second inclined portion 10d (inner circumferential end) of the metal core material 10. When the first sealing member 7 is mounted on the outer ring 3, its tip contacts the outer circumferential surface of the inner ring 2 (sealing the inner ring 2). By forming the first lip portion 11b inward in the axial direction in this way, the first lip portion 11b acts like a valve that prevents the lubricant (details to be described later) sealed in the annular space S1 from leaking out to the outside, thereby effectively preventing leakage of the lubricant from the annular space S1.

[0031] Furthermore, the second lip portion 11c is a sealing lip that contacts the outer circumferential surface of the inner ring 2, and extends diagonally outward in the axial direction from the second inclined portion 10d (inner circumferential end) of the metal core material 10, and is formed so that when the first sealing member 7 is mounted on the outer ring 3, its tip contacts the outer circumferential surface of the inner ring (sealing the inner ring 2). In this way, by forming the second lip portion 11c toward the axial outward direction, the second lip portion 11c acts as a valve that prevents foreign matter (e.g., dust, water, etc.) from entering the annular space S1, thereby effectively preventing foreign matter from entering the annular space S1.

[0032] The third lip portion 11d is a sealing lip that contacts the inner surface of the slinger 9, and extends diagonally outward in the axial direction from the inner circumference end of the first inclined portion 10c of the metal core material 10, and is formed so that its tip contacts the inner surface of the slinger 9 when the first sealing member 7 is mounted on the outer ring 3. The third lip portion 11d, by contacting the inner surface of the slinger 9, forms part of the seal that seals the annular space S1, and also forms an annular sealed space S2 between itself and the second sealing member 8, which will be described later (details will be described later).

[0033] The second sealing member 8 is an annular member positioned axially outward from the first sealing member 7, and consists of a metal slinger 9 and a second elastic member 12 integrally molded with the slinger 9.

[0034] The slinger 9 is made of an annular metal plate and, as shown in Figure 3, has a roughly L-shaped cross-section. Starting from the outer circumference, it has a vertical portion 9a positioned perpendicular to the inner ring 2, a first inclined portion 9b extending axially inward from the vertical portion 9a, a second vertical portion 9c extending perpendicularly from the first inclined portion 9b, and a base portion 9d extending perpendicularly to the second vertical portion 9c. The slinger 9 is mounted on the inner ring 2 by press-fitting the base portion 9d onto the outer surface of the inner ring 2. The second vertical portion 9c is the part that comes into contact with the third lip portion 11d of the first sealing member 7 when the slinger 9 is mounted on the inner ring 2, so its axially inward side surface (inner surface) is left exposed.

[0035] The second elastic member 12, like the elastic member 11, is made of an elastic material such as rubber, and in this embodiment, the rubber material is integrally molded with the slinger 9 by vulcanization molding.

[0036] Specifically, as shown in Figure 3, the second elastic member 12 is provided at the outer peripheral end of the vertical portion 9a of the slinger 9 and has a fourth lip portion 12a that contacts the axial end of the outer ring 3. As shown in the figure, the fourth lip portion 12a is formed at an angle toward the axial inward direction and is formed so that when the second sealing member 8 is mounted on the inner ring 2, its tip contacts the outer surface (axial end face portion) of the axial end of the outer ring 3 (sealing the outer ring 3).

[0037] Therefore, by positioning the second seal member 8 on the axially outer side of the first seal member 7, an annular sealed space S2 sealed by the second seal member 8 is formed on the axially outer side of the first seal member 7.

[0038] Next, we will briefly explain the manufacturing process of the rolling bearing 1 configured in this way. In the rolling bearing 1 according to the present invention, rolling elements 4 are arranged between the inner ring 2 and the outer ring 3 using a cage 6, and then the first seal member 7 is mounted on the outer ring 3. This mounting is performed by press-fitting the outer peripheral end of the first seal member 7 into a mounting groove 3b formed at the axial end of the inner circumferential surface of the outer ring 3. Specifically, the first seal member 7 is press-fitted so that its top portion 11a is inserted into a fitting groove 3c formed in the mounting groove 3b.

[0039] In this case, the annular space S1 is pre-filled with a lubricant for the rolling elements (for example, grease). That is, the rolling bearing 1 shown in this embodiment eliminates and omits the lubricant supply passage that communicates with the annular space, which was provided in conventional rolling bearings, and is configured to fill and seal the lubricant within the annular space S1. As a result, the rolling bearing 1 shown in this embodiment has a simpler structure compared to conventional rolling bearings, which reduces manufacturing costs, and eliminates the need for maintenance such as lubricant replenishment, thereby reducing the effort and cost of maintenance.

[0040] Next, once the first seal member 7 has been installed, the second seal member 8 is installed on the axially outward side of the first seal member 7. This installation is done by press-fitting the base 9d of the slinger 9 that constitutes the second seal member 8 onto the outer circumferential surface of the inner ring 2. Specifically, the second seal member 8 is press-fitted until the third lip portion 11d of the first seal member 7 contacts the inner surface of the slinger 9, and the fourth lip portion 12a of the second seal member 8 contacts the axial end of the outer ring 3.

[0041] In this process, the sealed space S2 formed between the first seal member 7 and the second seal member 8 is pre-filled with a lubricant (for example, grease), similar to the annular space S1 described above. That is, the seal member 8 is pressed into place, filling and sealing the sealed space S2 with lubricant.

[0042] Thus, according to the rolling bearing 1 of the present invention, the axial end of the annular space S1 formed between the inner ring 2 and the outer ring 3 is double-sealed by the first sealing member 7 and the second sealing member 8, so that a rolling bearing with high dustproof, waterproof, and sealing performance can be provided. In particular, the first sealing member 7 uses three lip portions 11b, 11c, and 11d to form a sealing structure, so a high sealing effect is achieved.

[0043] Furthermore, the first sealing member 7 employs a structure in which the first lip portion 11b extends axially inward to contact the inner ring 2, and the second lip portion 11c extends axially outward to contact the inner ring 2. As a result, the first lip portion 11b effectively prevents the lubricant for the rolling elements from leaking to the outside, while the second lip portion 11c effectively prevents dust and other particles from entering from the outside.

[0044] Furthermore, with the rolling bearing 1 according to the present invention, a high sealing effect can be obtained for the annular space S1 having the rolling elements 4, so that lubricant for the rolling elements can be filled and sealed inside the annular space S1. As a result, the lubricant supply passage that was provided in conventional rolling bearings can be eliminated, and a rolling bearing 1 can be provided that has a simple structure, can be manufactured at low cost, and requires less maintenance.

[0045] Furthermore, by filling and sealing the sealed space S2 formed between the first sealing member 7 and the second sealing member 8 with lubricant, the presence of this filled lubricant effectively prevents the intrusion of dust, water, and other external elements.

[0046] It should be noted that the embodiments described above merely represent preferred embodiments of the present invention, and the present invention is not limited to these, and various design modifications are possible within its scope.

[0047] For example, in the embodiment described above, the rolling bearing 1 was shown to be applied to an insert bearing, but the rolling bearing 1 according to the present invention can also be applied to structures other than insert bearings. Furthermore, although a deep groove ball bearing was shown as the rolling bearing 1 in the illustrated example, the rolling bearing according to the present invention can also be applied to other forms of rolling bearings, such as cylindrical roller bearings and tapered roller bearings.

[0048] Furthermore, in the above-described embodiment, the first sealing member 7 is shown to be mounted by press-fitting its outer peripheral end into a mounting groove 3b, which is a substantially L-shaped cutout at the axial end of the inner circumferential surface of the outer ring 3. However, the first sealing member 7 only needs to be mounted on the inner circumferential surface of the outer ring 3, and may be mounted using other structures.

[0049] Furthermore, in the above-described embodiment, the metal core material 10 of the first sealing member 7 was shown to be an annular metal plate having a head portion 10a, a vertical plate portion 10b, a first inclined portion 10c, and a second inclined portion 10d. However, the specific shape of the metal core material 10 can be appropriately changed as long as it is a metal plate that can integrally form the first lip portion 11b, the second lip portion 11c, and the third lip portion 11d. Similarly, in the above-described embodiment, the slinger 9 was shown to be an annular metal plate having a vertical portion 9a, a first inclined portion 9b, a second vertical portion 9c, and a base portion 9d. However, the specific shape of the slinger 9 can be appropriately changed as long as it is a metal plate that can integrally form the fourth lip portion 12a. [Explanation of Symbols]

[0050] 1 Rolling bearing 2 Inner ring 3 Outer ring 2a,3a Arc groove 3b Mounting groove 3c Insertion groove 4 Rolling elements 5. Seal structure 6 Cage 7. First sealing member 8. Second sealing member 9 Slinger 10 Metal core material 11 Elastic members 11a Top 11b First lip section 11c Second lip section 11d Third lip section 12 Second elastic member 12a Fourth lip section 100 bearing housing A rotation axis S1 Circular Space S2 Enclosed Space

Claims

1. A rolling bearing comprising an inner ring and an outer ring, and a plurality of rolling elements interposed between the inner ring and the outer ring, and having a sealing structure that seals the annular space formed between the inner ring and the outer ring, The seal structure comprises a first seal member that seals the axial end of the annular space, and a second seal member having a slinger positioned axially outward from the first seal member. The first sealing member is fitted into a mounting groove formed at the axial end of the inner circumferential surface of the outer ring and has first and second lip portions that contact the outer circumferential surface of the inner ring, and a third lip portion that contacts the inner surface of the slinger. The second sealing member is provided at the outer peripheral end of the slinger and has a fourth lip portion made of an elastic material that contacts the axial end of the outer ring. The first sealing member is composed of an annular metal core and an elastic member made of an elastic body integrally molded with the metal core. The elastic member has a top portion that covers the outer peripheral end of the metal core and the first, second, and third lip portions. When mounted on the outer ring, the top portion is inserted into a fitting groove formed in the mounting groove, the tips of the first and second lip portions contact the outer peripheral surface of the inner ring, and the tip of the third lip portion contacts the inner surface of the slinger. A rolling bearing characterized by the following.

2. The first lip portion extends axially inward from the inner circumferential end of the metal core material and contacts the outer circumferential surface of the inner ring. The second lip portion extends axially outward from the inner circumferential end of the metal core material and contacts the outer circumferential surface of the inner ring. The rolling bearing according to feature 1.

3. The annular space sealed by the first sealing member is filled and sealed with lubricant. A rolling bearing according to feature 1 or 2.

4. A lubricant is filled and sealed within the sealed space formed between the first sealing member and the second sealing member. A rolling bearing according to feature 1 or 2.

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