Bearing

Abstract

A bearing includes: an inner ring having an inner raceway; the outer ring is provided with an outer raceway; the rolling body is positioned between the inner raceway and the outer raceway; the retainer is used for retaining the rolling bodies; and a seal; lubricating oil exists in the free space in the bearing, the lubricating oil is at least attached to the surface of the inner raceway and the surface of the outer raceway, the volume of the lubricating oil accounts for less than 5% of the volume of the free space in the bearing, and the free space in the bearing is the space, except the rolling body and the retainer, in the free space in the bearing. The bearing internal space is a space defined by the inner ring, the outer ring, and the seal.

Description

Technical Field

[0001] The present disclosure relates to a bearing, and more particularly, to a bearing with a relatively small frictional torque. Background Art

[0002] Some devices using bearings require the bearings to have a relatively small frictional torque during operation; for example, in a lithium battery film winding machine, if the frictional torque of the bearing during operation is large, it may cause uneven film thickness or even film breakage.

[0003] Therefore, it is desirable to provide a bearing with a relatively small frictional torque during operation. Summary of the Invention

[0004] A bearing 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 for holding the rolling elements; and a seal; wherein, there is lubricating oil in the free space inside the bearing, the lubricating oil adheres to at least the surface of the inner raceway and the surface of the outer raceway, the volume of the lubricating oil accounts for less than 5% of the volume of the free space inside the bearing, the free space inside the bearing is the space inside the bearing excluding the rolling elements and the cage, and the internal space of the bearing is the space defined by the inner ring, the outer ring and the seal.

[0005] According to this solution, by using liquid lubricating oil as the lubricant and controlling the proportion of the volume of the lubricating oil in the volume of the free space inside the bearing to a certain specific value or less, the frictional torque suffered by the bearing during rotation is significantly reduced.

[0006] In some solutions, the oil film thickness of the lubricating oil adhering to the inner raceway and / or the outer raceway can be less than 0.06 mm; preferably, the oil film thickness can be greater than 0.01 mm and less than 0.05 mm.

[0007] In some solutions, the volume of the lubricating oil accounts for less than 3% of the volume of the free space inside the bearing; preferably less than 2%.

[0008] In some solutions, the relative groove curvature Ri of the inner raceway satisfies 0.52 ≤ Ri ≤ 0.58, and / or the relative groove curvature Re of the outer raceway satisfies 0.53 ≤ Re ≤ 0.58.

[0009] According to this solution, for a bearing with a relatively small diameter of the rolling elements, by using an inner raceway and / or an outer raceway with a relatively large relative groove curvature, the friction between the rolling elements and the inner ring and / or the outer ring is reduced, thereby significantly reducing the frictional torque suffered by the bearing during rotation and bringing an unexpected improvement to the overall performance of the bearing.

[0010] In some solutions, the diameter Dr of the rolling elements satisfies Dr ≤ 0.35 * (H1 - H2), where H1 is the outer diameter of the outer ring and H2 is the inner diameter of the inner ring.

[0011] In some embodiments, the viscosity of the lubricating oil at a temperature of 40 °C is less than 25 cst. Preferably, the viscosity of the lubricating oil at a temperature of 40 °C is less than 20 cst; more preferably, the viscosity of the lubricating oil at a temperature of 40 °C is less than 15 cst.

[0012] According to this embodiment, using a lubricating oil with a lower viscosity helps reduce the friction between the rolling elements and the inner and / or outer rings, thereby reducing the frictional torque during bearing rotation.

[0013] In some embodiments, a seal is provided at the axial end of the bearing. The seal is fixed to one of the outer ring or the inner ring, and a gap is provided between the seal and the other of the outer ring or the inner ring; preferably, the gap has a width extending in the radial direction of the bearing, and the width is between 0.1 mm and 0.2 mm; preferably, the gap has a length extending in the axial direction of the bearing, and the length is between 0.1 mm and 2 mm.

[0014] According to this embodiment, by adopting a non-contact seal, the friction between the seal and the outer or inner ring is reduced, thereby further reducing the frictional torque during bearing rotation.

[0015] According to a second aspect of the present disclosure, a method for attaching lubricating oil to a bearing is provided, including: immersing the bearing in the lubricating oil, the bearing including 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, and a seal; performing a centrifugal drying operation on the bearing to obtain a bearing in which the volume of the lubricating oil in the free space inside the bearing accounts for less than 5% of the volume of the free space inside the bearing; wherein, the lubricating oil is attached at least to the surfaces of the inner raceway and the outer raceway, the free space inside the bearing is the space inside the bearing excluding the rolling elements and the cage, and the internal space of the bearing is the space defined by the inner ring, the outer ring, and the seal.

[0016] According to a third aspect of the present disclosure, a winding cylinder is provided, including: a shaft; a bearing according to the first aspect of the present disclosure, disposed on the shaft; and a rotatable cylinder, disposed on the bearing. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 A schematic diagram of a bearing according to some embodiments of the present disclosure is shown;

[0018] Figure 2 A partial schematic diagram of a bearing according to some embodiments of the present disclosure is shown;

[0019] Figure 3 A schematic diagram of the relative groove curvature according to some embodiments of the present disclosure is shown;

[0020] Figure 4 Shows a partially enlarged schematic view of a seal according to some embodiments of the present disclosure;

[0021] Figure 5 Shows a flowchart of a method for attaching lubricating oil to a bearing according to some embodiments of the present disclosure.

[0022] Reference numerals: 100 bearing, 102 inner ring, 104 outer ring, 106 rolling elements, 108 cage, 110 inner raceway, 120 outer raceway, 130 seal, 140 clearance. Detailed implementation manners

[0023] In order to make the objectives, solutions, and advantages of the technical solutions of the present disclosure clearer, the technical solutions of some embodiments of the present disclosure will be clearly and completely described below with reference to the accompanying drawings of some embodiments of the present disclosure. Unless otherwise specified, the terms used herein have the ordinary meanings in the art. The same reference numerals in the drawings represent the same components.

[0024] Figure 1 and Figure 2 Shows a schematic view 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, a cage 108, and a seal 130. The inner ring 102 and the outer ring 104 can rotate concentrically relative to each other. The inner ring 102 and the outer ring 104 respectively have an inner raceway 110 and an outer raceway 120, and the rolling elements 106 are located between the inner raceway 110 and the outer raceway 120.

[0025] Different from the traditional lubrication method of applying grease in the bearing 100, the present disclosure coats lubricating oil instead of grease in the bearing 100, especially coats lubricating oil at the inner raceway 110 and / or the outer raceway 120 where the rolling elements 106 contact the bearing 100 to achieve the lubrication effect. Since the lubricating oil has a lower viscosity than the grease (for example, the viscosity at a temperature of 40 °C is less than 25 cst), compared with the solution of applying grease, coating the lubricating oil can reduce the friction between the rolling elements 106 and the inner raceway 110 and / or the outer raceway 120, thereby reducing the frictional torque received by the bearing 100 during rotation. Preferably, the viscosity of the lubricating oil at a temperature of 40 °C can be greater than 5 cst. In particular, in the case of using lubricating oil instead of grease, combined with the parameter of the volume ratio of the lubricating oil to the free space inside the bearing described below, the performance of the bearing, especially the friction performance, has an unexpected improvement. In some cases, the frictional torque received by the bearing 100 of the present solution during rotation is reduced by about 50% compared with the frictional torque of the bearings in the prior art during rotation.

[0026] In the bearing 100 of the present disclosure, the volume of the lubricating oil accounts for less than 5% of the volume of the free space inside the bearing. The free space inside the bearing is the space inside the bearing excluding the space of the rolling elements 106 and the cage 108. The internal space of the bearing is the space defined by the inner ring 102, the outer ring 104, and the seal 130. Using less lubricating oil helps to further reduce the friction between the rolling elements 106 and the inner ring 102 and / or the outer ring 104, thereby reducing the frictional torque when the bearing 100 rotates. This solution is particularly applicable when the external load on the bearing 100 is not large, because the oil film is not easily damaged by the external load due to its small volume. In addition, the volume of the lubricating oil can also account for less than 3% of the volume of the free space inside the bearing, which helps to further reduce the friction between the rolling elements 106 and the inner ring 102 and / or the outer ring 104, thereby further reducing the frictional torque when the bearing 100 rotates.

[0027] Preferably, the volume of the lubricating oil can also account for more than 2% of the volume of the free space inside the bearing. If the proportion of the volume of the lubricating oil in the free space inside the bearing is too small, the lubrication effect may be insufficient. Therefore, the proportion of the volume of the lubricating oil in the free space inside the bearing is set to be greater than 2% to achieve a sufficient lubrication effect. In the bearings in the prior art, the ratio of the volume of the lubricating material to the volume of the free space inside the bearing is usually very high, generally higher than 15%. However, the present disclosure designs a ratio of the volume of the lubricating material in the free space inside the bearing that is much lower than that of the bearings in the prior art, resulting in an unexpected improvement in the performance of the bearing, especially the frictional performance. In some cases, the frictional torque when the bearing 100 of this solution rotates is reduced by approximately 50% compared to the frictional torque when the bearings in the prior art rotate.

[0028] Correspondingly, an appropriate volume of lubricating oil can also be obtained by designing an appropriate oil film thickness of the lubricating oil. As Figure 2 shown, the thick black part represents the oil film, and the thickness formed in the radial direction of the bearing 100 is the oil film thickness. The relationship between the oil film thickness h and the oil film volume V is V = S * h, where S is the surface area of the oil film in contact with the outer surface of the inner ring 102 and the inner surface of the outer ring 104. In the solution of the present disclosure, the oil film thickness can be less than 0.05 mm. Using a thinner oil film helps to reduce the friction between the rolling elements 106 and the inner ring 102 and / or the outer ring 104, thereby reducing the frictional torque when the bearing 100 rotates. The oil film thickness can also be greater than 0.01 mm. If the oil film thickness is too thin, the lubrication effect may be insufficient. Therefore, the oil film thickness is set to be greater than 0.01 mm to achieve a sufficient lubrication effect. It should be understood that the present disclosure does not aim to limit the specific value of the oil film thickness, and lubricating oil with any other appropriate oil film thickness can be used.

[0029] To reduce the frictional torque exerted on such a bearing 100 during rotation, a relatively large relative groove curvature is designed for the inner raceway 110 and / or the outer raceway 120 of the bearing 100. The relative groove curvature can be defined as the radius of the raceway divided by the diameter of the rolling element 106; the radius of the raceway is the radius of the circle where the arc of the adapted raceway is located, that is, the radius of curvature of the raceway. That is to say, the relative groove curvature represents the degree of bending of the inner raceway 110 and / or the outer raceway 120 relative to the rolling element 106, which is equal to the ratio of the radius of curvature of the inner raceway 110 and / or the outer raceway 120 to the diameter of the rolling element 106. According to the definition of the relative groove curvature, if the relative groove curvature is equal to 0.5, it means that the degree of bending of the inner raceway 110 and / or the outer raceway 120 is the same as that of the rolling element 106. In order for the rolling element 106 to be accommodated in the inner raceway 110 and / or the outer raceway 120, obviously the relative groove curvature needs to be greater than 0.5.

[0030] In some embodiments, the relative groove curvature of the inner raceway 110 is greater than 0.52, and the relative groove curvature of the outer raceway 120 is greater than 0.53.

[0031] As Figure 3 shown, the relative groove curvature of the inner raceway 110 is less than the relative groove curvature of the inner raceway 110'. It can be intuitively seen from this that the larger the relative groove curvature of the inner raceway 110, the larger the clearance between the rolling element 106 and the inner raceway 110. It should be understood that the relative groove curvature of the outer raceway 120 is similar to that of the inner raceway 110, and for the sake of brevity, it will not be described in detail here, and Figure 3 is only schematic and not necessarily drawn to scale. In the bearing 100 of the present disclosure, the relative groove curvature of the inner raceway 110 is greater than 0.52 and / or the relative groove curvature of the outer raceway 120 is greater than 0.53. Appropriately designing a relatively large relative groove curvature of the inner raceway 110 and / or the outer raceway 120 makes the clearance between the rolling element 106 and the inner raceway 110 and / or the outer raceway 120 larger, which can reduce the friction between the rolling element 106 and the inner raceway 110 and / or the outer raceway 120, thereby reducing the frictional torque exerted on the bearing 100 during rotation. In some embodiments, the relative groove curvature Ri of the inner raceway 110 satisfies 0.52 ≤ Ri ≤ 0.58, and / or the relative groove curvature Re of the outer raceway 120 satisfies 0.53 ≤ Re ≤ 0.58. In some embodiments, the relative groove curvature Ri of the inner raceway 110 satisfies 0.54 ≤ Ri ≤ 0.56, and / or the relative groove curvature Re of the outer raceway 120 satisfies 0.55 ≤ Re ≤ 0.58.

[0032] In the bearings of the prior art, the relative groove curvature of the inner raceway 110 and / or the outer raceway 120 is not designed to be greater than 0.52, or even not set to be greater than 0.51. However, in the present disclosure, by designing the relative groove curvature of the inner raceway and / or the outer raceway of the bearing to be significantly greater than that of the bearings in the prior art, the performance of the bearing, especially the friction performance, has been unexpectedly improved. Particularly for the bearing 100 with a relatively small diameter of the rolling elements 106 (for example, the diameter Dr of the rolling elements 106 ≤ 0.35*(H1 - H2), where H1 and H2 are the outer diameter and the inner diameter of the outer ring 104 respectively), the frictional torque received by the bearing 100 during rotation is significantly reduced compared to the frictional torque received by the bearings in the prior art during rotation.

[0033] The present disclosure is particularly suitable for the bearing 100 with a relatively small diameter of the rolling elements 106. Specifically, when the diameter Dr of the rolling elements 106 ≤ 0.35*(H1 - H2), by combining technical features such as the volume ratio of the lubricating oil in the bearing free space, the oil film thickness, and the relative curvature of the raceway, the frictional torque received by the bearing 100 during rotation can be significantly reduced. Preferably, the inner diameter H2 of the inner ring satisfies 7 mm ≤ H2 ≤ 40 mm; more preferably, the inner diameter H2 of the inner ring satisfies 10 mm ≤ H2 ≤ 30 mm.

[0034] The low friction requirement restricts the diameter of the rolling elements 106. If the diameter of the rolling elements 106 is too large relative to the overall size of the bearing 100, a greater external force is required for the rotation of the rolling elements 106, resulting in higher friction. In addition, if the rolling elements 106 are too large relative to the overall size of the bearing 100, the overall size space of the bearing 100 will be compressed, causing the wall thicknesses of the inner ring 102 and the outer ring 104 to become thinner, increasing the processing difficulty. However, if the diameter of the rolling elements 106 is too small relative to the overall size of the bearing 100, it will bring extremely high processing difficulty to the cage and the seal 130. Therefore, in some embodiments, the diameter Dr of the rolling elements 106 ≥ 0.2*(H1 - H2); in some embodiments, the diameter Dr of the rolling elements 106 satisfies 0.25*(H1 - H2) ≤ Dr ≤ 0.32*(H1 - H2).

[0035] Preferably, a seal 130 may also be provided at the axial end of the bearing 100. The seal 130 is fixed to one of the outer ring 104 or the inner ring 102, and a slender-shaped gap 140 is provided between the seal 130 and the other of the outer ring 104 or the inner ring 102. In other words, the seal 130 may be fixed to the outer ring 104 and a gap 140 is provided between it and the inner ring 102, or the seal 130 may be fixed to the inner ring 102 and a gap 140 is provided between it and the outer ring 104. As Figure 4As shown, the gap 140 has a width L2 extending in the radial direction of the bearing 100 and a length L1 extending in the axial direction of the bearing 100. During the rotation of the bearing 100, this non-contact sealing of the seal 130 avoids the frictional torque generated on the bearing 100 due to the contact between the seal 130 and the outer surface of the inner ring 102 or the inner surface of the outer ring 104, thereby reducing the frictional torque suffered by the bearing 100 during rotation.

[0036] Preferably, the width L2 of the gap 140 between the seal 130 and the inner ring 102 can be between 0.1 mm and 0.2 mm. If the gap 140 is too wide, a good sealing effect cannot be obtained, while if the gap 140 is too narrow, it may cause the seal 130 to hinder the rotation of the bearing 100, thereby increasing the frictional torque suffered by the bearing 100 during rotation. Therefore, setting the width L2 of the gap 140 within a suitable range helps to both reduce the frictional torque suffered by the bearing 100 during rotation and basically isolate the internal space of the bearing from the external environment. In addition, the length L1 of the gap 140 between the seal 130 and the inner ring 102 can be between 0.1 mm and 2 mm.

[0037] Please refer to Figure 5 , the present disclosure also proposes a method for attaching lubricating oil to a bearing (for example, the bearing 100), wherein the lubricating oil is attached at least to the surfaces of the inner raceway 110 and the outer raceway 120. The free space inside the bearing is the space inside the bearing excluding the rolling elements 106 and the cage. The internal space of the bearing is the space defined by the inner ring 102, the outer ring 104, and the seal 130. In step S1, first, the bearing 100 is immersed in the lubricating oil, and then, in step S2, a centrifugal drying operation is performed on the bearing 100 to obtain a bearing in which the volume of the lubricating oil in the free space inside the bearing accounts for less than a specific value (for example, less than 5%) of the volume of the free space inside the bearing. In some embodiments, the volume of the lubricating oil of the obtained bearing accounts for less than 3% of the volume of the free space inside the bearing; preferably less than 2%. In some embodiments, the volume of the lubricating oil accounts for more than 0.5% of the volume of the free space inside the bearing.

[0038] In some embodiments, the viscosity of the lubricating oil at a temperature of 40 °C is less than 25 cst; preferably, the viscosity of the lubricating oil at a temperature of 40 °C is less than 20 cst; more preferably, the viscosity of the lubricating oil at a temperature of 40 °C is less than 15 cst.

[0039] In some embodiments, through the above steps, the oil film thickness of the lubricating oil attached to the inner raceway and / or the outer raceway is less than 0.06 mm; preferably, the oil film thickness is greater than 0.01 mm and less than 0.05 mm.

[0040] In some embodiments, the relative groove curvature Ri of the inner raceway satisfies 0.52 ≤ Ri ≤ 0.58, and / or the relative groove curvature Re of the outer raceway satisfies 0.53 ≤ Re ≤ 0.58. In some embodiments, the relative groove curvature Ri of the inner raceway satisfies 0.54 ≤ Ri ≤ 0.56, and / or the relative groove curvature Re of the outer raceway satisfies 0.55 ≤ Re ≤ 0.58.

[0041] In some embodiments, the diameter Dr of the rolling elements satisfies Dr ≤ 0.35*(H1 - H2), where H1 is the outer diameter of the outer ring and H2 is the inner diameter of the inner ring. In some embodiments, the diameter Dr of the rolling elements satisfies Dr ≥ 0.2*(H1 - H2); preferably, the diameter Dr of the rolling elements satisfies 0.25*(H1 - H2) ≤ Dr ≤ 0.32*(H1 - H2). In some embodiments, the inner diameter H2 of the inner ring satisfies 7 mm ≤ H2 ≤ 40 mm; preferably, the inner diameter H2 of the inner ring satisfies 10 mm ≤ H2 ≤ 30 mm.

[0042] In some embodiments, a seal is provided at the axial end of the bearing. The seal is fixed to one of the outer ring or the inner ring, and a gap is provided between the seal and the other of the outer ring or the inner ring; preferably, the gap has a width L2 extending in the radial direction of the bearing, and the width L2 is between 0.1 mm and 0.2 mm; preferably, the gap has a length L1 extending in the axial direction of the bearing, and the length L1 is between 0.1 mm and 2 mm.

[0043] The bearing 100 of the present disclosure can be used for a winding cylinder, which includes: a shaft, the bearing 100 provided on the shaft, and a rotatable cylinder provided on the bearing 100.

[0044] The present disclosure has been described in detail with reference to some preferred embodiments. However, those skilled in the art can understand that various modifications and variations can be made to the above specific embodiments without departing from the concept of the present disclosure. Various technical features and structures proposed by the present disclosure can also be combined without exceeding the protection scope of the present disclosure. The protection scope of the present disclosure is determined by the appended claims.

Claims

1. A bearing, characterized in that, 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; and Seals; Wherein, there is lubricating oil in the internal free space of the bearing, the lubricating oil adheres to at least the surfaces of the inner raceway and the outer raceway, the volume of the lubricating oil accounts for less than 5% of the volume of the internal free space of the bearing, the internal free space of the bearing is the space in the internal space of the bearing excluding the rolling elements and the cage, and the internal space of the bearing is the space defined by the inner ring, the outer ring and the seals.

2. The bearing according to claim 1, characterized in that, The oil film thickness of the lubricating oil adhering to the inner raceway and / or the outer raceway is less than 0.06 mm; preferably, the oil film thickness is greater than 0.01 mm and less than 0.05 mm.

3. The bearing according to claim 1, characterized in that, The volume of the lubricating oil accounts for less than 3% of the volume of the internal free space of the bearing; preferably less than 2%.

4. The bearing according to claim 3, characterized in that, The volume of the lubricating oil accounts for more than 0.5% of the volume of the internal free space of the bearing.

5. The bearing according to claim 1, characterized in that, The relative groove curvature Ri of the inner raceway satisfies 0.52 ≤ Ri ≤ 0.58, and / or, the relative groove curvature Re of the outer raceway satisfies 0.53 ≤ Re ≤ 0.

58.

6. The bearing according to claim 1, characterized in that, The diameter Dr of the rolling element ≤ 0.35 * (H1 - H2), where H1 is the outer diameter of the outer ring and H2 is the inner diameter of the inner ring.

7. The bearing according to claim 1, characterized in that, The viscosity of the lubricating oil at a temperature of 40 °C is less than 25 cst; preferably, the viscosity of the lubricating oil at a temperature of 40 °C is less than 20 cst; more preferably, the viscosity of the lubricating oil at a temperature of 40 °C is less than 15 cst.

8. The bearing according to claim 1, characterized in that, The seals are arranged at the axial ends of the bearing, the seals are fixed to one of the outer ring or the inner ring, and there is a gap between the seals and the other of the outer ring or the inner ring; preferably, the gap has a width L2 extending in the radial direction of the bearing, and the width L2 is between 0.1 mm and 0.2 mm; preferably, the gap has a length L1 extending in the axial direction of the bearing, and the length L1 is between 0.1 mm and 2 mm.

9. A method for attaching lubricating oil to a bearing, characterized in that, Comprising: Immersing the bearing in lubricating oil, the 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 and seals; Performing a centrifugal drying operation on the bearing to obtain a bearing in which the volume of the lubricating oil in the internal free space of the bearing accounts for less than 5% of the volume of the internal free space of the bearing; Wherein, the lubricating oil adheres to at least the surfaces of the inner raceway and the outer raceway, the internal free space of the bearing is the space in the internal space of the bearing excluding the rolling elements and the cage, and the internal space of the bearing is the space defined by the inner ring, the outer ring and the seals.

10. A winding cylinder, characterized in that, Comprising: A shaft; The bearing according to any one of claims 1 to 8, arranged on the shaft; And A rotatable cylinder, arranged on the bearing.

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