Rolling bearings

Abstract

To provide a rolling bearing with high dustproof, waterproof and sealing performance, which reduces the risk of dust, water and the like entering the inside of the bearing, and in particular, a rolling bearing suitable for an insert bearing. [Solution] A rolling bearing (1) having an inner ring (2), an outer ring (3), and a plurality of rolling elements (4) interposed between the inner ring (2) and the outer ring (3) is provided with a seal member (5) that seals an annular space (S) formed between the inner ring (2) and the outer ring (3). When the seal member (5) is attached to the inner peripheral surface of the outer ring (3), first to fourth lip portions (8d-8g) arranged in four layers in the axial direction each come into contact with the outer peripheral surface of the inner ring (2), sealing the annular space (S).

Description

[Technical Field]

[0001] The present invention relates to a rolling bearing, and more particularly to a sealing structure of a rolling bearing that is applied to an insert bearing. [Background technology]

[0002] Conventionally, rolling bearings are known that are equipped with a seal structure that prevents dust, water, etc. from entering the interior of the bearing. As shown in Figure 3, the seal structure of this type of rolling bearing generally consists of a seal material c attached to the bearing outer ring b and a slinger d attached to the outer periphery of the bearing inner ring a, but for rolling bearings used in locations that are strongly affected by dust, water, etc. (for example, rolling bearings used in insert bearings), a seal structure with higher dust-proof, waterproof, and sealing performance than general rolling bearings is desired.

[0003] 4 shows an example of a rolling bearing of a type intended for use as an insert bearing, with improved dustproofing, waterproofing, and sealing performance (see, for example, Patent Document 1). The illustrated rolling bearing has a plurality of rolling elements e, e, ... between an inner ring a and an outer ring b, and has, as a seal structure that seals the annular space f between the inner and outer rings, an annular shield g whose radial end is attached to the outer ring b, and a seal material h with three seal lips i whose tips contact the outer peripheral surface of the inner ring a, and is configured to seal the annular space f by the shield g and the three seal lips i.

[0004] In Fig. 4, the symbol j indicates the lubricant supply path to the annular space f, the symbol k indicates the bearing housing of the insert bearing, and the symbol m indicates the fixing screw for fixing the inner ring a to the rotating body n. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] See FIG. 9 of JP 2022-169216 A Summary of the Invention [Problem to be solved by the invention]

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

[0007] That is, the seal structure shown in FIG. 4 exhibits higher dustproof, waterproof, and sealing performance than the seal structure shown in FIG. 3, but even with this structure, dust, water, etc. can still get into the bearing when used in a location where it is strongly affected by dust, water, etc.

[0008] The present invention has been made in view of these problems, and its object is to provide a rolling bearing that has high dustproof, waterproof and sealing performance and reduces the risk of dust, water and the like entering the interior of the bearing, and in particular a rolling bearing that is suitable as an insert bearing. [Means for solving the problem]

[0009] In order to achieve the above object, the rolling bearing according to the present invention is a rolling bearing having an inner ring, an outer ring, and a plurality of rolling elements interposed between the inner ring and the outer ring, and equipped with a seal member that seals an annular space formed between the inner ring and the outer ring, the seal member being attached to the inner peripheral surface of the outer ring, and having first to fourth lip portions that contact the outer peripheral surface of the inner ring, each of which is arranged in four layers in the axial direction. Of the first to fourth lip portions, the first lip portion facing the annular space has its tip extending obliquely axially inward, and by attaching the seal member to the outer ring, its tip contacts the inner ring toward the inside in the axial direction, thereby sealing the space between itself and the inner ring; the second and third lip portions each extend downward, and by attaching the seal member to the outer ring, its tip contacts the outer peripheral surface of the inner ring, thereby sealing the space between itself and the inner ring; and the fourth lip portion, located outside the third lip portion, has its tip extending obliquely axially outward, and by attaching the seal member to the outer ring, its tip contacts the inner ring toward the outside in the axial direction, thereby sealing the space between itself and the inner ring. It is characterized by:

[0010] In this rolling bearing, the seal member is attached to the inner surface of the outer ring, so that first to fourth lip portions, arranged in four layers in the axial direction, each come into contact with the outer surface of the inner ring to form a seal structure, and these four seal lips effectively prevent dust, water, etc. from entering the interior of the bearing.

[0011] As a preferred embodiment of the present invention, the sealing member has an annular metal core material, and the first to fourth lip portions made of an elastic body are integrally molded with this metal core material.

[0012] In another preferred embodiment, the metal core has an elastic body integrally molded on at least the back side of the outer peripheral edge thereof.

[0014] Furthermore, in another preferred embodiment, the annular space sealed by the seal member is filled with a lubricant. [Effects of the Invention]

[0015] According to the present invention, first to fourth lip portions arranged in four layers in the axial direction each come into contact with the outer peripheral surface of the inner ring to form a seal structure, and the four seal lips prevent dust, water, etc. from entering the inside of the bearing. Therefore, according to the present invention, it is possible to provide a rolling bearing with high dustproof, waterproof, and sealing performance.

[0016] In particular, by constructing the first to fourth lip portions as one piece with an elastic body integrally molded onto an annular metal core, it is possible to avoid a decline in the dustproof, waterproof, and sealing performance of the first to fourth lip portions due to deformation of the seal member. In addition, by integrally molding an elastic body onto the back side of at least the outer peripheral edge of the metal core, dustproof, waterproof, and sealing effects can be obtained at the contact area between the seal member and the inner surface of the outer ring, and the seal member as a whole can achieve high dustproof, waterproof, and sealing performance.

[0017] Furthermore, according to the present invention, a high sealing effect can be obtained for the annular space containing the rolling elements, so that the annular space can be filled with lubricant for the rolling elements. This makes it possible to eliminate or omit the lubricant supply passage that communicates with the annular space, which is provided in conventional rolling bearings, and provides a rolling bearing that requires little maintenance. [Brief explanation of the drawings]

[0018] [Figure 1] 1 is a cross-sectional view showing an example of a rolling bearing according to the present invention. [Figure 2] FIG. 2 is an enlarged cross-sectional view showing an example of a seal member of the rolling bearing. [Figure 3] FIG. 1 is a cross-sectional view showing the structure of a conventional general rolling bearing. [Figure 4] FIG. 10 is a cross-sectional view showing the structure of another conventional rolling bearing. DETAILED DESCRIPTION OF THE INVENTION

[0019] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. 1 shows an example of a rolling bearing 1 according to the present invention. The illustrated rolling bearing 1 is a deep groove ball bearing used in insert bearings, and comprises as its main components an inner ring 2, an outer ring 3, a plurality of rolling elements 4 interposed between the inner ring 2 and the outer ring 3, and a seal member 5 that seals an annular space S formed between the inner ring 2 and the outer ring 3.

[0020] The inner ring 2 and outer ring 3 are annular metal members arranged coaxially, and arc grooves 2a, 3a that form 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. The rolling elements 4 are composed of spheres (balls), and a cage 6 holds a plurality of rolling elements 4 at regular intervals in the circumferential direction.

[0021] Furthermore, an attachment groove 3b for fitting a seal member 5 is formed on the inner peripheral surface of the outer ring 3. The attachment groove 3b is formed by grooving the axial end of the inner peripheral surface of the outer ring 3 into a generally L-shape, and an engagement groove 3c for fitting the outer peripheral end of the seal member 5 into this attachment groove 3b is formed over the entire circumferential length. Here, the axial direction means the axial direction of a rotating shaft A (see Figure 1) on which the rolling bearing 1 is mounted, and this applies similarly in the following description.

[0022] In the figure, reference numeral 100 denotes a bearing housing for the insert bearing, and the rolling bearing 1 is mounted inside this bearing housing 100. In the example shown, a spherical inner diameter surface 100a that engages with the outer diameter surface of the outer ring 3 is formed on the inner peripheral surface of the bearing housing 100, and the outer ring 3 of the rolling bearing 1 is fitted into this spherical inner diameter surface 100a, thereby housing the rolling bearing 1 inside the bearing housing 100. Also in the figure, reference numeral 101 denotes a mounting bolt for mounting the inner ring 2 to the rotating shaft A.

[0023] The sealing members 5 are members that seal the axial ends of the annular space S, and as shown in Fig. 1, are arranged symmetrically at both axial ends of the annular space S. Therefore, in the following explanation, the structure of one of the axial ends will be described, and the explanation of the other will be omitted.

[0024] The sealing member 5 is an annular member that is mounted in a mounting groove portion 3b formed on the inner peripheral surface of the outer ring 3, and is composed of an annular metal core material 7 and an elastic member 8 that is molded integrally with this metal core material 7 (see Figure 2).

[0025] The metal core material 7 is made of a ring-shaped metal plate, and as shown in Figure 2, has, from the outer periphery, a head portion 7a bent in an approximately C-shape so that it can be inserted into the fitting groove 3c, a standing portion 7b extending vertically from the head portion 7a, a first inclined portion 7c extending axially outward from the standing portion 7b, a second inclined portion 7d extending vertically from the first inclined portion 7c, and a second inclined portion 7e extending axially outward from the second standing portion 7d.

[0026] The elastic member 8 is made of an elastic material such as rubber, etc. In this embodiment, the elastic member 8 is molded integrally with the metal core member 7 by vulcanization molding of the rubber material.

[0027] Specifically, as shown in Figure 2, the elastic member 8 is formed mainly on the back side (axially inner side) of the metal core material 7, and has a top portion 8a that covers the head portion 7a of the metal core material 7, and a back portion 8b that is connected to the top portion 8a and covers at least the back side of the outer peripheral end portion of the metal core material 7, as well as a lip base portion 8c that is arranged below the first inclined portion 7c of the metal core material 7, and four lip portions 8d to 8g that protrude downward from the lip base portion 8c.

[0028] As shown, the top portion (outer peripheral end portion) of top portion 8a of elastic member 8 has a generally rectangular cross section that can fit into fitting groove 3c of outer ring 3, and this top portion 8a is inserted into fitting groove 3c when seal member 5 is press-fitted into outer ring 3. As a result, top portion 8a and the outer peripheral end portion of back portion 8b, which is formed contiguous with top portion 8a, come into tight contact with fitting groove 3c, and the inner circumferential surface of outer ring 3 is tightly sealed by the outer peripheral end portion of seal member 5.

[0029] The lip base portion 8c is a portion that constitutes the base on which the four lip portions 8d to 8g are formed, and is formed on the back side of the first inclined portion 7c and the second upright portion 7d of the metal core material 7, as shown in Fig. 2. In this embodiment, the lip base portion 8c has a generally rectangular cross section. First to fourth seal lips (first lip portion 8d, second lip portion 8e, third lip portion 8f, fourth lip portion 8g), whose tips respectively contact the outer peripheral surface of the inner ring 2, are arranged in four layers in the axial direction at the inner peripheral end of the lip base portion 8c.

[0030] The first lip portion 8d is the innermost of the four seal lips and faces the annular space S containing the rolling elements 4. It extends obliquely from the inner peripheral end portion on the back side of the lip base portion 8c toward the axially inner side (toward the rolling elements 4), and when the seal member 5 is attached to the outer ring 3, its tip comes into contact with the outer peripheral surface of the inner ring 2, sealing the space between the inner ring 2. In this case, as shown in FIG. 1, the tip of the first lip portion 8d comes into contact with the inner ring 2 toward the axially inner side, and therefore functions as a valve that prevents, in particular, the lubricant (described in detail below) filled in the annular space S from leaking out. Therefore, the lubricant filled in the annular space S is sealed within the annular space S without risk of leaking out.

[0031] The second lip portion 8e and the third lip portion 8f are seal lips located outside the first lip portion 8d and extend downward as shown in FIG. 2. When the seal member 5 is attached to the outer ring 3, their tips contact the outer peripheral surface of the inner ring 2, sealing the gap between the inner ring 2 and the second lip portion 8e and the third lip portion 8f. As shown in FIG. 2, the second lip portion 8e and the third lip portion 8f are formed slightly longer than the first lip portion 8d. Therefore, when the seal member 5 is attached to the outer ring 3, the tips of the second lip portion 8e and the third lip portion 8f contact the outer peripheral surface of the inner ring 2 while bending slightly outward in the axial direction. As a result, the second lip portion 8e and the third lip portion 8f function to prevent the intrusion of dust, water, and other external contaminants. Therefore, the second lip portion 8e and the third lip portion 8f enhance dustproofing, waterproofing, and sealing effects.

[0032] The fourth lip portion 8g is a seal lip located outside the third lip portion 8f, and as shown in FIG. 2, it extends obliquely axially outward from the inner peripheral end portion on the surface side of the lip base portion 8c along the second inclined portion 7e of the metal core 7. When the seal member 5 is attached to the outer ring 3, its tip contacts the outer peripheral surface of the inner ring 2, sealing the space between the inner ring 2 and the fourth lip portion 8g. In this case, unlike the first lip portion 8d described above, the tip of the fourth lip portion 8g contacts the inner ring 2 axially outward, and therefore functions particularly like a valve that prevents the intrusion of dust, water, and the like from the outside. This effectively prevents the intrusion of dust, water, and the like into the bearing.

[0033] In this way, in the rolling bearing 1 shown in this embodiment, the annular space S is sealed by the sealing member 5, and at that time, the gap that occurs between it and the outer ring 3 is completely blocked by the outer peripheral end of the elastic member 8 fitted into the fitting groove 3c, and the gap that occurs between it and the inner ring 2 is completely blocked by the four-layer seal lip made up of the first to fourth lip portions 8d to 8g, resulting in a rolling bearing 1 with high dustproof, waterproof and sealing performance.

[0034] Next, a manufacturing process for the rolling bearing 1 configured as above will be briefly described. In the rolling bearing 1 according to the present invention, after the rolling elements 4 have been placed between the inner ring 2 and outer ring 3 using a cage 6, a seal member 5 is attached to the outer ring 3. This attachment is performed by press-fitting the outer peripheral end of the seal member 5 into an attachment groove 3b formed at the axial end of the inner peripheral surface of the outer ring 3. Specifically, the seal member 5 is press-fitted into the outer ring 3 so that the top portion 8a of the seal member 5 is inserted into the fitting groove 3c formed in the attachment groove 3b.

[0035] At this time, the annular space S is filled in advance with a lubricant (for example, grease) for the rolling elements, and the lubricant is sealed within the annular space S by attaching the sealing member 5. In other words, the rolling bearing 1 shown in this embodiment employs a structure that does away with or omits the lubricant supply passage that communicates with the annular space, which is provided in conventional rolling bearings, and is configured to seal the lubricant within the annular space S. As a result, the rolling bearing 1 shown in this embodiment has a simpler structure than conventional rolling bearings, making it possible to keep manufacturing costs low, and does not require maintenance such as lubricant replenishment, thereby reducing the effort and cost required for maintenance.

[0036] Thus, according to the rolling bearing 1 of the present invention, the axial end of the annular space S formed between the inner ring 2 and the outer ring 3 is sealed by the sealing member 5 having four seal lips, thereby providing a rolling bearing 1 with high dustproof, waterproof and sealing performance.

[0037] The above-described embodiments are merely preferred embodiments of the present invention, and the present invention is not limited to these, and various design modifications are possible within the scope of the present invention.

[0038] For example, in the above-described embodiment, the rolling bearing 1 is applied to an insert bearing, but the rolling bearing 1 according to the present invention can be applied to structures other than insert bearings. Also, in the illustrated example, a deep groove ball bearing is shown as the rolling bearing 1, but the rolling bearing 1 according to the present invention can be applied to other types of rolling bearings, such as cylindrical roller bearings and tapered roller bearings.

[0039] Furthermore, in the above-described embodiment, the sealing member 5 is attached by press-fitting the outer peripheral end portion of the sealing member 5 into an attachment groove portion 3b, which is a generally L-shaped notch cut out from the axial end portion of the inner peripheral surface of the outer ring 3; however, the sealing member 5 may be attached using another structure as long as it is attached to the inner peripheral surface of the outer ring 3.

[0040] Furthermore, in the above-described embodiment, the metal core material 7 of the sealing member 5 is shown to be composed of an annular metal plate having a head 7a, a standing portion 7b, a first inclined portion 7c, a second standing portion 7d, and a second inclined portion 7e, but the metal core material 7 may be any metal plate having a shape that allows the first to fourth lip portions 8d to 8g that come into contact with the inner ring 2 to be integrally molded, and its specific shape can be changed as appropriate.

[0041] Furthermore, in the above-described embodiment, when mounting the rolling bearing 1 on the rotating shaft A, a threaded hole for inserting the set screw 101 is formed in the inner ring 2, and the inner ring 2 is fastened to the rotating shaft A by the set screw 101. However, the rolling bearing 1 according to the present invention may also be configured to be mounted on the rotating shaft A using a mounting device other than the set screw 101 (for example, a mounting adapter consisting of an adapter sleeve, nut, stopper, etc.). [Explanation of symbols]

[0042] 1. Rolling bearings 2. Inner circle 3 outer ring 2a, 3a Arc groove 3b Mounting groove 3c Fitting groove 4 rolling elements 5 Sealing material 6 Cage 7 Metal core material 8 Elastic member 8a Top 8b Back part 8d First lip 8e Second lip 8f Third lip 8g 4th lip 100 Bearing box A rotation axis S Annular Space

Claims

1. A rolling bearing having an inner ring, an outer ring, and a plurality of rolling elements interposed between the inner ring and the outer ring, and provided with a seal member that seals an annular space formed between the inner ring and the outer ring, the seal member is attached to the inner peripheral surface of the outer ring, and first to fourth lip portions that contact the outer peripheral surface of the inner ring are arranged four times in the axial direction, a first lip portion of the first to fourth lip portions facing the annular space has a tip extending obliquely inward in the axial direction, and by attaching the seal member to the outer ring, the tip extends inward in the axial direction and contacts the inner ring to seal between the outer ring and the inner ring, the second and third lip portions each extend downward, and when the seal member is attached to the outer ring, their tips come into contact with the outer peripheral surface of the inner ring to seal between the outer ring and the inner ring, The fourth lip portion, which is disposed on the outside of the third lip portion, has a tip extending obliquely outward in the axial direction, and by attaching the seal member to the outer ring, the tip extends outward in the axial direction and contacts the inner ring, thereby sealing the space between the inner ring and the fourth lip portion. A rolling bearing characterized by:

2. The seal member has an annular metal core, and the first to fourth lip portions made of an elastic body are integrally molded with the metal core.

2. The rolling bearing according to claim 1 .

3. The metal core member has an elastic body integrally molded at least on the back side of its outer peripheral end.

3. The rolling bearing according to claim 2.

4. The annular space sealed by the seal member is filled with a lubricant.

4. A rolling bearing according to claim 1, wherein the rolling bearing is a bearing having a diameter of 100 mm or less.

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