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Abstract

A bearing comprising: an inner ring having an inner raceway; an outer ring having an outer raceway; rolling elements located between the inner raceway and the outer raceway; a cage for retaining the rolling elements; wherein a relative groove curvature Ri of the inner raceway satisfies Ri ≥ 0.545 and / or a relative groove curvature Re of the outer raceway satisfies Re ≥ 0.545; and wherein an inner diameter d of the bearing satisfies 24 mm ≤ d ≤ 30 mm and a radial clearance Gr satisfies 13 µm ≤ Gr ≤ 41 µm or the inner diameter d of the bearing satisfies 6 mm ≤ d ≤ 10 mm and the radial clearance Gr satisfies 8 µm ≤ Gr ≤ 29 µm.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to a bearing and, more particularly, to a bearing that can mitigate the problem of bearing sticking. BACKGROUND

[0002] For a bearing operating at high temperatures and low speeds, the bearing's lubrication performance deteriorates because grease hardens quickly at high temperatures and the lubricating oil cannot sufficiently separate from the lubricant at low speeds. As a result, the bearing is prone to seizing and failure during operation, shortening the bearing's service life and even creating potential safety risks.

[0003] Therefore, there is a need to provide a bearing that can mitigate the problem of sticking during operation at high temperatures and low speeds. SUMMARY

[0004] According to a first aspect of the present disclosure, there is provided a bearing comprising: an inner ring having an inner raceway; an outer ring having an outer raceway; rolling elements located between the inner raceway and the outer raceway; a cage for holding the rolling elements; wherein a relative groove curvature Ri of the inner raceway satisfies Ri ≥ 0.545 and / or a relative groove curvature Re of the outer raceway satisfies Re ≥ 0.545; and wherein an inner diameter d of the bearing satisfies 24 mm ≤ d ≤ 30 mm and a radial clearance Gr satisfies 13 µm ≤ Gr ≤ 41 µm, or the inner diameter d of the bearing satisfies 6 mm ≤ d ≤ 10 mm and the radial clearance Gr satisfies 8 µm ≤ Gr ≤ 29 µm.

[0005] For bearings operating at high temperatures and low speeds, such a solution can reduce the problems of wear, sticking, and even locking of the bearing during operation by using a bearing with a large radial clearance and a large relative groove curvature, and improve the reliability and service life of the bearing.

[0006] In some solutions, the bearing inner diameter d satisfies 24 mm ≤ d ≤ 30 mm, and the radial clearance Gr satisfies 23 µm ≤ Gr ≤ 36 µm. Preferably, the bearing inner diameter d satisfies 24 mm ≤ d ≤ 30 mm, and the radial clearance Gr satisfies 23 µm ≤ Gr ≤ 28 µm. More preferably, the bearing inner diameter d satisfies 6 mm ≤ d ≤ 10 mm, and the radial clearance Gr satisfies 8 µm ≤ Gr ≤ 14 µm.

[0007] In some solutions, the relative groove curvature Ri of the inner raceway satisfies Ri ≥ 0.55, and / or the relative groove curvature Re of the outer raceway satisfies Re ≥ 0.55.

[0008] In some solutions, the relative groove curvature Ri of the inner race satisfies Ri ≤ 0.57, and / or the relative groove curvature Re of the outer race satisfies Re ≤ 0.57. Preferably, the relative groove curvature Ri of the inner race satisfies Ri ≤ 0.555, and / or the relative groove curvature Re of the outer race satisfies Re ≤ 0.555.

[0009] In some solutions, the Rockwell hardness of the inner raceway and / or outer raceway material could be less than or equal to 62 HRC. Preferably, the Rockwell hardness of the inner raceway and / or outer raceway material is greater than or equal to 58 HRC.

[0010] By using the inner raceway and / or the outer raceway with lower hardness, such a solution allows the inner raceway and / or the outer raceway to be deformed more easily, thereby reducing the problems of wear and sticking of the bearing during operation.

[0011] In some solutions, lubricant is applied to the inner raceway and outer raceway, and the oil separation rate of the lubricant is greater than 1%.

[0012] By using a lubricant with a high oil separation efficiency, according to such a solution, even under the operating condition of a low rotational speed of the bearing, more lubricating oil can be separated from the lubricant, thereby reducing the friction between the rolling elements and the inner ring and / or the outer ring and further reducing the problems of wear and sticking of the bearing during operation.

[0013] In some solutions, respective surfaces of the inner raceway and / or the outer raceway may be formed of an oxidation-resistant material.

[0014] According to such a solution, the problem that the bearing is rapidly oxidized during operation at high temperatures can be solved, thereby improving the performance of the bearing and extending the service life of the bearing.

[0015] In some solutions, the retained austenite of the inner raceway and / or outer raceway material may be less than 3%.

[0016] Some solutions require a bearing speed of ≤ 14,000 rpm and an operating temperature of ≤ 250 °C. Preferably, the bearing operating temperature is ≤ 200 °C.

[0017] In some solutions, the bearing speed during operation is ≤ 5 rpm, and the bearing operating temperature range is 140±5 °C. Preferably, the bearing speed during operation is ≤ 0.5 rpm. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 shows a schematic view of a bearing according to some embodiments of the present disclosure; Fig. 2 shows a schematic partial view of a bearing according to some embodiments of the present disclosure; Fig. 3 shows a schematic view of the relative groove curvature according to some embodiments of the present disclosure; Fig. 4 shows a schematic view of the radial clearance according to some embodiments of the present disclosure.

[0018] Reference numbers: 100 bearing, 102 inner ring, 104 outer ring, 106 rolling element, 108 cage, 110 inner raceway, 120 outer raceway. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0019] To further clarify the purpose, solutions, and advantages of the technical regime of the present disclosure, technical solutions of some embodiments of the present disclosure are described clearly and completely below with the accompanying drawings of some specific embodiments of the present disclosure. Unless otherwise indicated, the terms used herein have the common meaning known to those skilled in the art. In the drawings, the same reference numerals refer to the same parts.

[0020] Fig. 1 and Fig. 2 show schematic views of a bearing 100 according to some embodiments of the present disclosure. The bearing 100 includes an inner ring 102, an outer ring 104, rolling elements 106, and a cage 108. The inner ring 102 and the outer ring 104 can rotate concentrically with each other, and the inner ring 102 and the outer ring 104 have an inner raceway 110 and an outer raceway 120, respectively, with the rolling elements 106 disposed between the inner raceway 110 and the outer raceway 120. Lubricant is applied to the inner raceway 110 and the outer raceway 120.

[0021] The present disclosure relates to the bearing 100 that operates under conditions of high temperature (for example, about 140°C) and low rotational speed (for example, less than 5 rpm or even less than 0.5 rpm). Since the lubricating grease quickly hardens at high temperature and the lubricating oil cannot be sufficiently separated from the lubricant at low rotational speed, the lubricating performance of the bearing deteriorates. As a result, the bearing is prone to seizure and failure during operation, which shortens the service life of the bearing and even causes potential safety hazards. To reduce problems such as wear and seizure in this type of bearing 100 during rotation, the bearing 100 is designed with a relatively large groove curvature of the raceways and a relatively large radial clearance.

[0022] Regarding the groove curvature of the raceways, as in Fig. 3, a relative groove curvature can be defined as the result of dividing a raceway radius by the diameter of the rolling element 106, and the raceway radius is the radius of the circle where the raceway arc is located. That is, the relative groove curvature Ri of the inner raceway 110 is the result of dividing the radius of the inner raceway 110 by the diameter of the rolling element 106. The relative groove curvature Re of the outer raceway 120 is the result of dividing the radius of the outer raceway 120 by the diameter of the rolling element 106. The relative groove curvature indicates the degree of curvature of the inner raceway 110 and / or the outer raceway 120 relative to the rolling element 106. If the relative groove curvature is equal to 0.5, according to the definition of the relative groove curvature, this means that the degree of curvature of the inner raceway 110 and / or the outer raceway 120 is the same as that of the rolling element 106.To accommodate the rolling elements 106 in the inner raceway 110 and / or the outer raceway 120, the relative groove curvature must, of course, be greater than 0.5. In . Fig. 3, the relative groove curvature of the inner raceway 110 (solid line) is smaller than that of the inner raceway 110' (dashed line), from which it can be intuitively seen that the larger relative groove curvature of the inner raceway 110 means a larger gap between the rolling element 106 and the inner raceway 110. It is understood that the relative groove curvature of the outer raceway 120 is similar to that of the inner raceway 110 and will not be described in detail here in the interest of brevity, and that Fig. 3 is only schematic and not necessarily drawn to scale. More specifically, the bearing 100 is configured such that the relative groove curvature Ri of the inner raceway 110 satisfies Ri ≥ 0.545 and / or the relative groove curvature Re of the outer raceway 120 satisfies Re ≥ 0.545. In some embodiments, Ri ≥ 0.55. In some embodiments, 0.545 ≤ Ri ≤ 0.57. Preferably, 0.545 ≤ Ri ≤ 0.555. More preferably, 0.55 ≤ Ri ≤ 0.555. In some embodiments, Re ≥ 0.55. In some embodiments, 0.545 ≤ Re ≤ 0.57. Preferably, 0.545 ≤ Re ≤ 0.555 is used. Particularly preferred is 0.55 ≤ Re ≤ 0.555.

[0023] Regarding the radial clearance, as in Fig.4, the radial clearance Gr is defined by Gr = de - Di - 2 × Dw, where de is the diameter of the groove bottom of the outer ring raceway, Di is the diameter of the groove bottom of the inner ring raceway, and Dw is the diameter of the rolling element 106. In some embodiments, the inner diameter d of the bearing 100 satisfies 24 mm ≤ d ≤ 30 mm and the radial clearance Gr satisfies 13 µm ≤ Gr ≤ 41 µm. Preferably, the radial clearance Gr satisfies 23 µm ≤ Gr ≤ 36 µm. More preferably, the radial clearance Gr satisfies 23 µm ≤ Gr ≤ 28 µm. In some embodiments, the inner diameter d of the bearing 100 satisfies 6 mm ≤ d ≤ 10 mm, and the radial clearance Gr satisfies 8 µm ≤ Gr ≤ 29 µm. Preferably, the radial clearance Gr satisfies 8 µm ≤ Gr ≤ 14 µm.

[0024] In one aspect, the larger relative groove curvature of the inner raceway 110 and / or the outer raceway 120 increases the arcuate gap between the rolling element 106 and the inner raceway 110 and / or the outer raceway 120, and in another aspect, the larger radial clearance increases the radial gap between the rolling element 106 and the raceway. By combining the two aspects described above, the axial and radial movement space of the rolling element 106 is simultaneously ensured in the high-temperature operating environment, thereby reducing the friction between the rolling element 106 and the raceway in the high-temperature environment, which in turn mitigates problems of wear and sticking of the bearing 100 during operation.Furthermore, a change in the relative groove curvature or radial clearance affects the operation of the bearing in such a way that a change in one parameter also affects the parameter design of the other, as long as the overall design requirements of the bearing remain unchanged. Under the application requirements of the above embodiments, the two cannot simply be separated and dimensioned separately. By controlling the relative groove curvature and radial clearance, the movement space of the rolling element 106 can be better controlled during the operation of the bearing 100.

[0025] If the relative groove curvature is too large, this may lead to a problem of reducing the load-bearing capacity of the bearing 100, and if the radial clearance is too large, this may lead to a problem of excessive vibration of the bearing 100 during operation. Therefore, in some embodiments, not only a preferred lower limit but also a preferred upper limit are specified for the relative groove curvature and the radial clearance.

[0026] Preferably, a lower hardness can be specified for the material of the inner raceway 110 and / or the outer raceway 120. More specifically, the Rockwell hardness of the material of the inner raceway and / or the outer raceway could be less than or equal to 62 HRC. By using the inner raceway and / or the outer raceway with a lower hardness, the inner raceway and / or the outer raceway can be more easily deformed, thereby reducing the problems of wear and sticking of the bearing during operation at high temperatures and low speeds. On the other hand, to avoid excessive deformation and fatigue failure of an excessively soft raceway under the compression of the rolling element 106, the Rockwell hardness of the material of the inner raceway 110 and / or the outer raceway 120 is preferably greater than or equal to 58 HRC.

[0027] Preferably, lubricant may be applied to the inner raceway 110 and the outer raceway 120, and a high oil separation efficiency may be provided for the lubricant. Specifically, the oil separation efficiency of the lubricant may be greater than 1%. By using a lubricant with a high oil separation efficiency, more lubricating oil can be separated from the lubricant even under the condition of a low rotational speed of the bearing 100, thereby reducing the friction between the rolling elements 106 and the inner ring 102 and / or the outer ring 104, and alleviating the problems of wear and seizure of the bearing 100 during low-speed operation.

[0028] Preferably, the respective surfaces of the inner raceway 110 and / or the outer raceway 120 can be made of an oxidation-resistant material, and the oxidation-resistant material meets the requirement of no red rust formation within 72 hours in a salt spray test according to DIN EN ISO 9227 NSS. This technical feature can mitigate the problem of the bearing 100 rapidly oxidizing during operation under high-temperature and oxygen-enriched conditions, thereby improving the performance of the bearing 100 and extending the service life of the bearing 100.

[0029] Preferably, the residual austenite of the material of the inner raceway 110 and / or the outer raceway 120 may be less than 3%.

[0030] In some embodiments, the rotational speed of the bearing 100 during operation is ≤ 14,000 rpm and the operating temperature of the bearing 100 is ≤ 250 °C. Preferably, the operating temperature of the bearing is 100 ≤ 200 °C.

[0031] In some embodiments, the rotational speed of the bearing 100 during operation is ≤ 5 rpm, and the operating temperature range of the bearing is 140±5°C. Preferably, the rotational speed of the bearing during operation is ≤ 0.5 rpm. An extremely low-speed operating environment combined with a prolonged and relatively constant high temperature poses significant challenges to the operation of the bearing. By simultaneously adjusting the relative groove curvature and radial clearance, the problems of wear and sticking of the bearing 100 during operation in a high-temperature environment are mitigated. By improving the lubricant and surface treatment, the problem of sticking of the bearing 100 at extremely low speeds is mitigated.

[0032] A number of exemplary embodiments of the present disclosure have been described in detail herein with reference to some preferred embodiments. However, it will be apparent to those skilled in the art that various variations and modifications can be made to the specific embodiments described above without departing from the concept of the present disclosure, and that various technical features and structures proposed in the present disclosure can be combined without departing from the scope of the present disclosure, which is determined by the appended claims.

Claims

[1] camp, characterized by that it includes: an inner ring having an inner raceway; an outer ring having an outer raceway; Rolling elements located between the inner raceway and the outer raceway; a cage to hold the rolling elements; wherein a relative groove curvature Ri of the inner race satisfies Ri ≥ 0.545 and / or a relative groove curvature Re of the outer race satisfies Re ≥ 0.545; and where an inner diameter d of the bearing satisfies 24 mm ≤ d ≤ 30 mm and a radial clearance Gr 13 µm ≤ Gr ≤ 41 µm or the inner diameter d of the bearing satisfies 6 mm ≤ d ≤ 10 mm and the radial clearance Gr 8 µm ≤ Gr ≤ 29 µm. [2] Bearing according to claim 1, characterized bythat the inner diameter d of the bearing satisfies 24 mm ≤ d ≤ 30 mm and the radial clearance Gr satisfies 23 µm ≤ Gr ≤ 36 µm; preferably the inner diameter d of the bearing satisfies 24 mm ≤ d ≤ 30 mm and the radial clearance Gr satisfies 23 µm ≤ Gr ≤ 28 µm. [3] Bearing according to claim 1, characterized by that the inner diameter d of the bearing satisfies 6 mm ≤ d ≤ 10 mm and the radial clearance Gr 8 µm ≤ Gr ≤ 14 µm. [4] Bearing according to claim 1, characterized by that the relative groove curvature Ri of the inner raceway satisfies Ri ≥ 0.55 and / or the relative groove curvature Re of the outer raceway satisfies Re ≥ 0.

55. [5] Bearing according to claim 1, characterized by that the relative groove curvature Ri of the inner raceway satisfies Ri ≤ 0.57 and / or the relative groove curvature Re of the outer raceway satisfies Re ≤ 0.57; preferably the relative groove curvature Ri of the inner raceway satisfies Ri ≤ 0.555 and / or the relative groove curvature Re of the outer raceway satisfies Re ≤ 0.

555. [6] Bearing according to claim 1, characterized by that the Rockwell hardness of the material of the inner raceway and / or the outer raceway is less than or equal to 62 HRC; preferably the Rockwell hardness of the material of the inner raceway and / or the outer raceway is more than or equal to 58 HRC. [7] Bearing according to claim 1, characterized by that lubricant is applied to the inner raceway and the outer raceway and an oil separation degree of the lubricant is greater than 1%. [8] Bearing according to claim 1, characterized by that respective surfaces of the inner raceway and / or the outer raceway are formed of an oxidation-resistant material. [9] Bearing according to claim 1, characterized by that the retained austenite of the inner raceway and / or outer raceway material is less than 3%. [10] Bearing according to claim 1, characterized bythat the rotational speed of the bearing during operation is ≤ 14,000 rpm and the operating temperature of the bearing is ≤ 250 °C; preferably the operating temperature of the bearing is less than or equal to 200 °C. [11] Bearing according to claim 1, characterized by that the speed of the bearing during operation is ≤ 5 rpm and the operating temperature range of the bearing is 140±5 °C; preferably the speed of the bearing during operation is ≤ 0.5 rpm.

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