Sealed bearing

Abstract

The objective is to provide a sealed bearing that can effectively suppress lip wear during high-speed rotation of the bearing and prevent damage resulting therefrom. [Solution] The sealed bearing (bearing 100) according to the present invention is a sealed bearing that rotatably supports the shaft end Sa, which is the end of a shaft S, and comprises an outer race 110, an inner race 120, rolling elements (balls 130) that roll between the outer race 110 and the inner race 120, and a seal 140 that seals the space between the outer race 110 and the inner race 120, wherein the seal 140 is fitted onto the outer race 110 and has a lip 146 that slides with the inner race 120, and the contact point between the lip 146 and the inner race 120 is located inside the outer circumferential surface Sb of the shaft S.

Description

Technical Field

[0001] The present invention relates to a sealed bearing that rotatably supports a shaft end, which is an end portion of a shaft.

Background Art

[0002] Seals may be provided in bearings to prevent foreign matter from entering between the outer and inner rings and to prevent leakage of lubricant. For example, Patent Document 1 discloses "an electrically conductive rolling bearing including an outer ring having an outer ring race on an inner peripheral surface, an inner ring having an inner ring race on an outer peripheral surface, a plurality of rolling elements rotatably provided between these outer ring race and inner ring race, and an annular seal ring that exists between the inner peripheral surface of the outer ring and the outer peripheral surface of the inner ring and closes an end opening of a bearing inner space in which these respective rolling elements are installed."

[0003] In the electrically conductive rolling bearing of Patent Document 1, "one peripheral edge of both inner and outer peripheral edges of the seal ring is locked to one end portion of either the end portion of the inner ring or the end portion of the outer ring over the entire circumference, and the other peripheral edge of both the inner and outer peripheral edges is slidably contacted over the entire circumference with the surface of the other end portion of either the end portion of the inner ring or the end portion of the outer ring, and further, the outer ring and the inner ring are electrically connected."

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In recent years, bearings have become larger in diameter and rotated at higher speeds. As a result, the peripheral speed at the contact point between the outer ring (hereinafter referred to as the outer race) or inner ring (hereinafter referred to as the inner race) of the bearing and the lip of the seal has increased. This has led to issues such as the lip being damaged or overheating due to friction during high-speed bearing rotation, and further improvements are needed.

[0006] In view of these problems, the present invention aims to provide a sealed bearing that can suitably suppress lip wear during high-speed rotation of the bearing and prevent damage caused thereby. [Means for solving the problem]

[0007] To solve the above problems, a typical configuration of the sealed bearing according to the present invention is a sealed bearing that rotatably supports the end of a shaft, the shaft end, and comprises an outer race, an inner race, rolling elements that roll between the outer race and the inner race, and a seal that seals the space between the outer race and the inner race, wherein the seal has a lip that fits onto the outer race and slides against the inner race, and the contact point between the lip and the inner race is located inside the outer circumferential surface of the shaft.

[0008] In this application, "outer race" is almost synonymous with "outer ring," but "inner race" includes not only the annular "inner ring" but also a solid cylindrical member with a raceway surface formed on its outer surface.

[0009] The inner race described above comprises a cylindrical portion that fits onto the outer surface of the shaft and a flange portion that faces the end of the shaft, with the contact point preferably located on the flange portion.

[0010] The inner race described above is cylindrical in shape and fitted onto the end of the shaft, and the contact point is preferably located on the outer surface of the cylindrical shape.

[0011] To solve the above problems, another configuration of the sealed bearing according to the present invention is a sealed bearing that rotatably supports a shaft end, which is the end of a shaft, comprising an outer race, an inner race fitted to the outer circumferential surface of the shaft, rolling elements that roll between the outer race and the inner race, and a fitted seal that seals the space between the outer race and the inner race, wherein the seal comprises a lip fitted to the outer race and sliding with the shaft, and the contact point between the lip and the shaft is located at the shaft end or the outer circumferential surface of the shaft. [Effects of the Invention]

[0012] According to the present invention, it is possible to provide a sealed bearing that can suitably suppress lip wear during high-speed rotation of the bearing and prevent damage caused thereby. [Brief explanation of the drawing]

[0013] [Figure 1] This is a diagram illustrating a sealed bearing according to the first embodiment. [Figure 2] This is a diagram illustrating a sealed bearing according to a second embodiment. [Figure 3] This is a diagram illustrating a sealed bearing according to a third embodiment. [Figure 4] This is a diagram illustrating a conventional sealed bearing. [Modes for carrying out the invention]

[0014] Preferred embodiments of the present invention will be described in detail below with reference to the attached drawings. The dimensions, materials, and other specific numerical values ​​shown in these embodiments are merely illustrative to facilitate understanding of the invention and do not limit the present invention unless otherwise specified. In this specification and drawings, elements having substantially the same function or configuration are denoted by the same reference numerals to avoid redundant explanations, and elements not directly related to the present invention are not shown or described.

[0015] (Conventional sealed bearings) First, the prior art will be explained using Figure 4. Figure 4 is a diagram illustrating a conventional sealed bearing (hereinafter referred to as bearing 10). The conventional bearing 10 illustrated in Figure 4 rotatably supports the shaft end Sa, which is the end of the shaft S. The bearing 10 consists of an outer race 12, an inner race 14, balls 16 which are rolling elements that roll between the outer race 12 and the inner race 14, and a seal 20.

[0016] The seal 20 seals the space between the outer race 12 and the inner race 14. The seal 20 is composed of a core metal 22 and an elastic material 24 supported by it, with a lip 26 formed at the tip of the elastic material 24. One end (root end) of the seal 20 is fitted into the outer race 12, and the other end (tip) of the seal 20 slides against the inner race 14 at the lip 26.

[0017] In the conventional bearing 10 illustrated in Figure 4, the contact point P0 between the lip 26 and the inner race 14 is located on the outer race 12 side of the outer circumferential surface Sb of the shaft S. In other words, the contact point P0 is further from the center of the shaft S than the outer circumferential surface Sb. This is because the contact point P0 is on the outer circumferential surface (outer race 12 side) of the inner race 14, and since the inner race 14 has thickness, the contact point P0 is inevitably further from the center of the shaft S than the outer circumferential surface Sb of the shaft S. In such a conventional configuration, wear and premature failure of the lip 26 have become a problem as bearings have become larger in diameter and rotated at higher speeds.

[0018] (First Embodiment) Figure 1 is a diagram illustrating a sealed bearing (hereinafter referred to as bearing 100) according to the first embodiment. The bearing 100 of the first embodiment shown in Figure 1 rotatably supports the shaft end Sa, which is the end of the shaft S. The bearing 100 is composed of an outer race 110, an inner race 120, balls 130 which are rolling elements that roll between the outer race 110 and the inner race 120, and a seal 140.

[0019] The seal 140 seals between the outer race 110 and the inner race 120. The seal 140 is composed of a core metal 142 and an elastic material 144 supported thereby, and a lip 146 is formed at the tip of the elastic body 144.

[0020] As a feature of the bearing 100 of the first embodiment, the inner race 120 has a cylindrical portion 122 that fits onto the outer peripheral surface Sb of the shaft S, and a flange portion 124 that faces the shaft end Sa. The flange portion 124 extends from the cylindrical portion 122 toward the center of the shaft S in a direction covering the shaft end Sa. Note that the "outer peripheral surface Sb of the shaft S" refers to the outer peripheral surface within the range where the inner race 120 is fitted, rather than the outer peripheral surface at any arbitrary location of the shaft S.

[0021] In the bearing 100 of the first embodiment, one end of the seal 140 is fitted onto the outer race 110, and the other end of the seal 140 slides on the flange portion 124 of the inner race 120 at the lip 146. The contact point P1 between the lip 146 and the inner race 120 is set at a position rp closer to the center than the radius rs from the center of the shaft S to the outer peripheral surface Sb.

[0022] According to the above configuration, the contact point P1 is located inside the outer peripheral surface Sb of the shaft S, that is, on the center side of the shaft S. Therefore, since the circumferential speed at the contact point P1 between the lip 146 and the inner race 120 is lower than that of the contact point P0 of the conventional bearing 10, wear of the lip 146 during high-speed rotation of the bearing 100 can be preferably suppressed, and damage resulting therefrom can be prevented.

[0023] (Second Embodiment) FIG. 2 is a diagram for explaining a sealed bearing (hereinafter referred to as bearing 200) according to the second embodiment. In the bearing 200 of the second embodiment, components that are substantially the same as those of the bearing 100 of the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

[0024] In the bearing 200 of the second embodiment, the inner race 220 has a raceway surface 222 formed on the outer circumferential surface of a solid cylindrical member, and is fitted into a fitting hole Sc formed in the shaft end Sa. The lip 146 slides against the outer circumferential surface 220a of the cylindrical inner race 220. The contact point P2 between the lip 146 and the inner race 220 is set at a position rp that is closer to the center than the radius rs from the center of the shaft S to the outer circumferential surface Sb. Note that "outer circumferential surface Sb of the shaft S" refers to the outer circumferential surface in the area in which the inner race 220 is fitted, not the outer circumferential surface at any point on the shaft S.

[0025] In the above configuration as well, the contact point P2 is located inside the outer circumferential surface Sb of the shaft S, that is, towards the center of the shaft S. Therefore, the peripheral speed at the contact point P2 between the lip 146 and the inner race 220 is lower than that at the contact point P0 of the conventional bearing 10, making it possible to obtain the same effect as the bearing 100 of the first embodiment.

[0026] (Third embodiment) Figure 3 is a diagram illustrating a sealed bearing (hereinafter referred to as bearing 300) according to the third embodiment. In bearing 300 of the third embodiment, components that are substantially the same as those of bearing 100 of the first embodiment are denoted by the same reference numerals and their description is omitted.

[0027] The bearing 300 shown in Figure 3 rotatably supports the shaft end Sa, which is the end of the shaft S. In both the bearing 100 in Figure 1 and the bearing 200 in Figure 2, one end of the seal 140 is fitted into the outer race 110, and the other end of the seal 140 slides against the inner race 120 at the lip 146. In contrast, in the bearing 300 shown in Figure 3, one end of the seal 140 is fitted into the outer race 110, and the lip 146 at the other end of the seal 140 slides against the shaft end Sa.

[0028] In detail, in the bearing 300 shown in Figure 3, the inner race 320 is fitted onto the outer circumferential surface Sb of the shaft S, and the end face 322 of the inner race 320 is positioned inward from the end face 112 of the outer race 110. As a result, the seal 140 fitted onto the outer race 110 is separated from the inner race 320, and the lip 146 slides against the shaft end Sa at the contact point P3.

[0029] In the above configuration as well, the contact point P3 is located inside the outer circumferential surface Sb of the shaft S, that is, towards the center of the shaft S. Therefore, the peripheral speed at the contact point P3 between the lip 146 and the shaft end Sa is lower than that at the contact point P0 of the conventional bearing 10, making it possible to obtain the same effect as the bearing 100 of the first embodiment.

[0030] In the third embodiment, the lip 146 was illustrated and described as contacting the shaft end Sa (end face), but it may also be configured to contact the outer circumferential surface Sb of the shaft S. Of course, contacting the shaft end Sa allows for a lower peripheral speed, but contacting the outer circumferential surface Sb of the shaft S also allows for a lower peripheral speed than when it is in contact with the inner ring as in the conventional case.

[0031] Preferred embodiments of the present invention have been described above with reference to the attached drawings, but it goes without saying that the present invention is not limited to these examples. It is clear to those skilled in the art that various modifications or alterations can be conceived within the scope of the claims, and these will naturally also fall within the technical scope of the present invention. [Industrial applicability]

[0032] This invention can be used as a sealed bearing that rotatably supports the shaft end, which is the end of a shaft. [Explanation of Symbols]

[0033] P0...Contact point, P1...Contact point, P2...Contact point, P3...Contact point, 10...Bearing, 12...Outer race, 14...Inner race, 16...Ball, 20...Seal, 22...Core metal, 24...Elastic material, 26...Lip, 100...Bearing, 110...Outer race, 120...Inner race, 122...Cylindrical section, 124...Flange section, 130...Ball, 140...Seal, 142...Core metal, 144...Elastic material, 146...Lip, 200...Bearing, 220...Inner race, 220a...Outer surface, 222...Raceway surface, 300...Bearing, 320...Inner race, 322...End face, S...Shaft, Sa...Shaft end, Sb...Outer surface, Sc...Matching hole

Claims

1. A sealed bearing that rotatably supports the end of a shaft, Outer lace and, Inner lace and A rolling element that rolls between the outer race and the inner race, The outer race and the inner race are sealed together, The seal is fitted onto the outer race and has a lip that slides against the inner race, A sealed bearing characterized in that the contact point between the lip and the inner race is located inside the outer circumferential surface of the shaft.

2. The inner race comprises a cylindrical portion that fits onto the outer circumferential surface of the shaft and a flange portion that faces the end of the shaft. The sealed bearing according to claim 1, characterized in that the contact point is located on the flange portion.

3. The inner race is cylindrical in shape and fits inside the shaft end. The sealed bearing according to claim 1, characterized in that the contact points are arranged on the outer surface of the cylindrical shape.

4. A sealed bearing that rotatably supports the end of a shaft, Outer lace and, An inner race fitted to the outer surface of the shaft, A rolling element that rolls between the outer race and the inner race, The outer race is fitted with a seal that seals the space between the inner races, The seal is fitted into the outer race and has a lip that slides against the shaft, A sealed bearing characterized in that the contact point between the lip and the shaft is located at the shaft end or on the outer circumferential surface of the shaft.

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