Deep groove ball bearings

Abstract

A deep groove ball bearing is disclosed, comprising an outer ring, an inner ring, balls arranged between the outer and inner rings, and a cage for holding the balls. The outer ring has an outer raceway, the outer raceway defines an outer raceway radius, the ratio of the outer raceway radius to the diameter of the balls defines a first ratio, and two edges of the outer raceway in the axial direction define an outer raceway boundary angle relative to the center of the arc of the outer raceway. The inner ring has an inner raceway, the inner raceway defines an inner raceway radius, the ratio of the inner raceway radius to the diameter of the balls defines a second ratio, and two edges of the inner raceway in the axial direction define an inner raceway boundary angle relative to the center of the arc of the inner raceway.The range of the first ratio is 0.525 - 0.570, the range of the second ratio is 0.510 - 0.530, the range of the outer ring raceway limit angle is 66° - 97°, and the range of the inner ring raceway limit angle is 72° - 99°. Compared to the prior art, the deep groove ball bearing exhibits a significantly reduced frictional torque.

Description

TECHNICAL FIELDThe present invention relates to the field of mechanical equipment, in particular a deep groove ball bearing.BACKGROUNDBearings are used for supporting mechanically rotating bodies in mechanical equipment. A bearing changes the sliding friction between a rotating shaft and a shaft seat to rolling friction, thereby reducing the friction loss.A deep groove ball bearing is one type of bearing. A deep groove ball bearing generally includes an outer ring, an inner ring, balls disposed between the outer ring and the inner ring, and a cage for holding the balls. The outer ring and the inner ring of the deep groove ball bearing have an outer ring raceway and an inner ring raceway, respectively. When the bearing runs, the balls move in the space defined between the outer ring raceway and the inner ring raceway.During the movement of the balls, an interaction takes place between the outer ring and the balls of the bearing and between the inner ring and the balls of the bearing. This interaction includes friction, so that the bearing still has a certain friction torque. To reduce friction, lubricating oil or grease may generally be used to lubricate the parts. However, there is still a need to improve the structures of the bearing parts in order to improve the existing lubricating effect.SUMMARYIn view of the above problems, according to a first aspect of the present invention, there is provided a deep groove ball bearing including an outer ring, an inner ring, balls disposed between the outer ring and the inner ring, and a cage for holding the balls, the outer ring having an outer ring raceway, the outer ring raceway defining an outer ring raceway radius, the ratio of the outer ring raceway radius to the diameter of the balls defining a first ratio, and two edges of the outer ring raceway in the axial direction defining an outer ring raceway boundary angle relative to the center of the arc of the outer ring raceway, the inner ring having an inner ring raceway, the inner ring raceway defining an inner ring raceway radius, the ratio of the inner ring raceway radius to the diameter of the balls defining a second ratio, and two edges of the inner ring raceway in the axial direction define an inner ring raceway boundary angle relative to the center of the arc of the inner ring raceway, wherein the range of the first ratio is 0.525-0.570, the range of the second ratio is 0.510-0.530, the range of the outer ring raceway boundary angle is 66°-97°, and the range of the inner ring raceway boundary angle is 72°-99°.The applicant has found that in a deep groove ball bearing according to the present invention, by commonly controlling the respective raceway radii and raceway restriction angles of the outer ring and the inner ring, the friction torque of the bearing can be effectively reduced. According to the results of the tests conducted by the applicant, the deep groove ball bearing of the present invention can significantly reduce the friction torque as compared with the deep groove ball bearings of the prior art, as will be described in detail later.In addition, due to the limitation of the respective raceway radii and raceway limitation angles of the outer ring and the inner ring in the present invention, the shoulder surfaces on both sides of the outer ring raceway of the deep groove ball bearing may be closer to the radially outer surface of the outer ring, and the shoulder surfaces on both sides of the inner ring raceway of the deep groove ball bearing may be closer to the radially inner surface of the inner ring. Therefore, the weight of the entire bearing can be reduced, which contributes to a lower weight of the equipment.The deep groove ball bearing according to the present invention may have one or more of the following characteristics.According to an embodiment, the range of the first ratio is 0.530-0.565, the range of the second ratio is 0.515-0.530, the range of the outer ring raceway boundary angle is 69°-94°, and the range of the inner ring raceway boundary angle is 76°-96°.According to an embodiment, preferably, the range of the first ratio is 0.535-0.560, the range of the second ratio is 0.520-0.530, the range of the outer ring raceway boundary angle is 72°-84°, and the range of the inner ring raceway boundary angle is 80°-92°.The above embodiments are preferred embodiments of the present invention, resulting in a further reduced frictional torque of the deep groove ball bearing.According to one embodiment, the deep groove ball bearing preferably contains grease. This embodiment enables the deep groove ball bearing to have a further reduced friction torque with grease.According to one embodiment, the viscosity of the grease is preferably less than 40 mm 2 / s . at 40° CAccording to one embodiment, the viscosity of the grease is preferably less than 30 mm 2 / s . at 40° C. The above embodiments enable the deep groove ball bearing to have a further reduced friction torque.According to one embodiment, the cage is preferably made of a polymer. The deep groove ball bearing according to an embodiment is lighter in weight, which contributes to light weight of the entire equipment.According to one embodiment, the cage is preferably a nylon plastic cage.According to one embodiment, the cage preferably contains a material capable of adsorbing lubricating oil or grease.According to one embodiment, the cage is preferably provided with an opening or pore for storing lubricating oil or grease. The deep groove ball bearing according to the above embodiments helps to hold an appropriate amount of lubricating oil or grease between the balls and the outer ring, the inner ring, and the cage, thereby improving the overall lubricating effect and reducing the friction torque.BRIEF DESCRIPTION OF THE DRAWINGSIn order to more clearly clarify the technical solutions of the embodiments of the present disclosure, the accompanying drawings of the embodiments of the present disclosure will be briefly presented below. The accompanying drawings are used only to illustrate some embodiments of the present disclosure, but do not limit all embodiments of the present disclosure thereto. FIG. 1 is a perspective sectional view of an embodiment of a deep groove ball bearing according to the present invention. FIG. 2 is a schematic radial sectional view of an embodiment of the deep groove ball bearing according to the present invention. FIG. 3 is another schematic radial sectional view of an embodiment of the deep groove ball bearing according to the present invention. FIG. 4 is a part of a schematic sectional view of the embodiment of the deep groove ball bearing according to the present invention, wherein the sectional plane is the central plane of the deep groove ball bearing orthogonal to the axial direction. FIGS. 5A-5C are radial sectional views of various embodiments of the deep groove ball bearing according to the present invention.List of reference numerals 1 outer ring 10 outer ring raceway 11 first shoulder of outer ring 12 second shoulder of outer ring 13 first edge of outer ring raceway 14 second edge of outer ring raceway 15 center of arc of outer ring raceway 2 inner ring 20 inner ring raceway 21 first shoulder of inner ring 22 second shoulder of inner ring 23 first edge of inner ring raceway 24 second edge of inner ring raceway 25 center of arc of inner ring raceway 3 balls 30 ball center 4 cage 5 grease 6 sealDETAILED DESCRIPTION OF THE EMBODIMENTSIn order to make the purpose, the technical solution, and the advantages of the technical solutions of the present disclosure more clear, the technical solutions of the embodiments of the present disclosure will be described clearly and fully hereinafter with reference to the drawings of specific embodiments of the present disclosure. In the drawings, the same reference numerals denote the same parts. It should be noted that the described embodiments are part of, but not all of, the embodiments of the present disclosure. Based on the described embodiments of the present disclosure, all other embodiments obtained by those skilled in the art without inventive efforts fall within the scope of the present disclosure.Unless otherwise defined, the technical or scientific terms used herein have their usual meanings as understood by one of ordinary skill in the art to which this invention pertains. The words "first", "second", and the like used in the specification and claims of the patent application of the present disclosure do not indicate an order, a number, or a meaning, but are used only to distinguish various components. Likewise, the words "a / an" and the like do not necessarily mean a quantity limitation. The words "comprise" or "include", and the like mean that the items or objects recited before the word include the items or objects recited after the word and their equivalents without excluding other items or objects. "Top", "Bottom", "Left", and "Right" are used only to express a relative positional relationship. When the absolute position of the object being described changes, the relative positional relationship may also change accordingly.The present disclosure will be described in detail below with reference to exemplary embodiments.FIG. 1 shows a perspective view of an embodiment of a deep groove ball bearing 100 according to the present invention. As shown in FIG. 1, the deep groove ball bearing 100 includes an outer ring 1, an inner ring 2, balls 3 interposed between the outer ring 1 and the inner ring 2, and a cage 4 for holding the balls 3. Although not shown in FIG. 1, the deep groove ball bearing 100 shown in FIG. 1 has a set of balls 3 between its outer ring 1 and its inner ring 2 for the operation of the deep groove ball bearing 100. In addition, the deep groove ball bearing 100 shown in FIG. 1 further includes two annular seals 6 disposed on both sides of the balls 3 in the axial direction to prevent the entry of dust between the outer ring 1 and the inner ring 2. However, according to other embodiments of the present invention, seals of the deep groove ball bearing may be adjusted so as to prevent leakage of lubricating oil or grease between the outer ring 1 and the inner ring 2, or the deep groove ball bearing may be provided with no seal.Further, as shown in FIG. 1, the outer ring 1 has an outer ring raceway 10, and the inner ring 2 has an inner ring raceway 20. The outer ring raceway 10 and the inner ring raceway 20 each accommodate a part of each ball 3, so that the balls 3 can roll relative to the outer ring 1 and the inner ring 2 in the annular space formed by the outer ring raceway 10 and the inner ring raceway 20.As shown in FIG. 2, the outer ring raceway 10 has an arc shape in the radial section of the deep groove ball bearing 100, and the radius re of this arc is the outer ring raceway radius re.The inner ring raceway 20 has an arc shape in the radial section of the deep groove ball bearing 100, and the radius ri of this arc is the inner ring raceway radius ri. FIG. 2 also shows the center 30 of a ball 3 and the radius r of the ball 3. the ratio of the outer ring raceway radius re to the diameter 2 rof the ball 3 defines a first ratio fe=re / 2 r, and the ratio of the inner ring raceway radius ri to the diameter 2 rof the ball 3 defines a second ratio fi=ri / 2 r. According to an embodiment of the deep groove ball bearing 100 of the present invention, the range of the first ratio fe is 0.525 to 0.570, and the range of the second ratio fi is 0.510 to 0.530. That is, the outer ring raceway radius re and the inner ring raceway radius ri are both slightly larger than the radius r of the ball 3. Thus, as shown in FIG. 2, the center 15 of the arc of the outer ring raceway 10 is farther from the outer ring raceway 10 than the center 30 of the ball 3, and the center 25 of the arc of the inner ring raceway 20 is farther from the inner ring raceway 20 than the center 30 of the ball 3.In addition, as shown in FIG. 2, the outer ring raceway 10 has two annular edges, namely, a first edge 13 and a second edge 14. the first edge 13 and the second edge 14 are respectively annular edges at both ends of the outer ring raceway 10 in the axial direction of the bearing. The inner ring raceway 20 has two annular edges, namely, a first edge 23 and a second edge 24. the first edge 23 and the second edge 24 are respectively annular edges at both ends of the inner ring raceway 20 in the axial direction of the bearing. The first edge 13 and the second edge 14 of the outer ring raceway 10 define an outer ring raceway boundary angle Ae with respect to the center 15 of the arc of the outer ring raceway 10, and the first edge 23 and the second edge 24 of the inner ring raceway 20 define an inner ring raceway boundary angle Ai with respect to the center 25 of the arc of the inner ring raceway 20.In the deep groove ball bearing 100 according to the present invention, by limiting the first ratio fe, the second ratio fi, the outer ring raceway limiting angle Ae, and the inner ring raceway limiting angle Ai within the above-mentioned combination of ranges, the friction torque of the bearing can be effectively reduced.Further, according to a first preferred embodiment of the present invention, the range of the first ratio fe is 0.530 to 0.565, the range of the second ratio fi is 0.515 to 0.530, the range of the outer ring raceway limitation angle Ae is 69° to 94°, and the range of the inner ring raceway limitation angle Ai is 76° to 96°.According to a second preferred embodiment of the present invention, the range of the first ratio fe is 0.535 to 0.560, the range of the second ratio fi is 0.520 to 0.530, the range of the outer ring raceway limitation angle Ae is 72° to 84°, and the range of the inner ring raceway limitation angle Ai is 80° to 92°.According to a third preferred embodiment of the present invention, the deep groove ball bearing contains grease.According to a fourth preferred embodiment of the present invention, the viscosity of the grease at 40° C. is less than 40 mm 2 / s .According to a fifth preferred embodiment of the present invention, the viscosity of the grease at 40°C is less than 30 mm 2 / s .In tests conducted for deep groove ball bearings having the above geometries, these deep groove ball bearings exhibit the ability to significantly reduce the frictional torque. In the tests, the respective inner geometries of these deep groove ball bearings correspond to the above-mentioned combinations of areas, and the respective outer geometries correspond to the Applicant's Model 6208-2Z / C3 bearing. These deep groove ball bearings are each provided with a nylon plastic cage and are filled with grease having a viscosity of less than 40 mm 2 / s at 40° C. During the tests, the speed of the bearings is 3600 U / min, the load comprises the general radial load and axial preload, and the ratio of the base dynamic rated load C to the equivalent dynamic load P of the bearing is C / P=20.In addition, the applicant has measured, as a comparison, the friction torque of existing deep groove ball bearings 6208-2Z / C3 under the same conditions. For such deep groove ball bearings, fe=0.523-0.530, fi=0.508-0.515, Ae=98°-102°, Ai=100°-105°. The existing deep groove ball bearings used in the comparative tests are also equipped with a nylon plastic cage and are filled with the same type of grease, and in the comparative experiments the same load setting is used.The test results show that the friction torque of the deep groove ball bearing according to the present invention is significantly less than the friction torque of the existing deep groove ball bearing measured in the comparative experiments, that the friction torque of the deep groove ball bearings according to the first preferred embodiment of the present invention is further reduced, and that the friction torque of the deep groove ball bearings according to the second preferred embodiment of the present invention is less. In particular, the test results show that the friction torque of the deep groove ball bearing according to a preferred embodiment of the present invention can be reduced by 70% compared with that of the existing deep groove ball bearings.FIG. 3 shows another schematic radial sectional view of the embodiment of the deep groove ball bearing 100 according to the present invention in order to help explain the advantages of the deep groove ball bearing according to the present invention. In FIG. 3, only a part of the balls 3 and the inner ring 2 is shown, so that the interaction between the balls 3 and the inner ring 2 and between the balls 3 and the outer ring 1 will be described with reference to the example of the inner ring 2. For better clarification, the radius ri of the inner ring raceway 20 is shown enlarged in FIG. 3, in order to show the first edge 23 and the second edge 24 of the inner ring raceway 20 more clearly.The frictional torque of the deep groove ball bearing in operation is generated by the frictional force to which the outer ring or the inner ring of the bearing is subjected. The frictional force is influenced by many factors, and there are also interactions between these factors. In the related art, there are studies on the influence of the ratio fe and fi of the raceway to the ball diameter on reducing the friction torque, but there is no public research project or research result on the influence of coupling fe and fi with Ae and Ai on the friction torque.On the other hand, in the deep groove ball bearing of the present application, the friction torque of the bearing can be significantly reduced by commonly controlling the respective ranges of the first ratio fe, the second ratio fi, the outer ring raceway limitation angle Ae, and the inner ring raceway limitation angle Ai. The possible reasons which result from the Applicant's analysis are listed below.As shown in FIG. 3, during operation of the bearing, the respective surfaces of the ball 3 and the inner ring raceway 20 press against each other, thereby forming a contact portion 26. In the contact portion 26, the ball 3 applies a compressive load σ to the inner ring 2 in the radial direction of the bearing, and in the contact portion 26, both the ball 3 and the inner ring raceway 20 are elastically deformed. Such elastic deformation is constantly generated and relieved during the rolling process of the ball 3, which generates elastic resistance that resists the relative movement between the ball 3 and the inner ring 2, and this elastic resistance becomes a part of the frictional force to which the bearing is subjected.In another aspect, as shown in FIGS. 3 and 4, the grease 5 is located in the clearance between the surface of the ball 3 and the surface of the inner ring raceway 20. the grease 5 plays a lubricating role during the relative movement between the ball 3 and the inner ring raceway 20, particularly in the contact region 26. Now, when the ball 3 rolls relative to the inner ring raceway 20, it pushes out the grease 5 in the clearance before the contact region 26 (see FIG. 4 ), so that the movement of the grease 5 also generates a resistance that counteracts the rolling of the ball 3, and as a result, another part of the frictional force to which the bearing is subjected is generated.Therefore, based on reducing the contact area between the ball 3 and the raceway surface by increasing the respective radii re and ri of the outer ring raceway 10 and the inner ring raceway 20, thereby reducing the frictional force, by appropriately reducing the arc length of the outer ring raceway 10 and the inner ring raceway 20 in the radial section of the bearing, for example, by controlling the outer ring raceway restriction angle Ae and the inner ring raceway restriction angle Ai, the dynamic process of displacing the grease 5 by the ball 3 can be affected, which can result in reduction of the frictional force. In addition, the respective radii of the outer ring raceway 10 and the inner ring raceway 20 contribute to the shape of the clearance spaces between the ball 3 and the respective surfaces of the two raceways, so that the respective radii of the outer ring raceway 10 and the inner ring raceway 20 also influence the dynamic process of displacing the grease 5 by the ball 3, thereby reducing the frictional force.In other words, the first ratio fe, the second ratio fi, the outer ring raceway restriction angle Ae, and the inner ring raceway restriction angle Ai all influence the friction torque of the bearing differently, and the specific shape of the deep groove ball bearing that the applicant found according to the present invention can significantly reduce the friction torque. In addition, the applicant has found that when grease is used in the deep groove ball bearing according to the present invention, in particular grease having a viscosity at 40° C. of less than 40 mm 2 / s, a friction torque significantly reduced as compared with that of the deep groove ball bearing of the prior art can be obtained, and this optimized effect can also be related to the specific combinations of the ranges of fe, fi, Ae and Ai.Figures 5A-5C illustrate further embodiments according to the present invention. In the deep groove ball bearing shown in FIG. 5A, the cage 4 is a steel cage. In the deep groove ball bearing shown in FIG. 5B, the cage 4 is a nylon resin cage. According to other embodiments of the present invention, the cage 4 may also be made of other materials, such as a polymeric material. Moreover, in an embodiment not shown according to the present invention, the cage of the bearing may be provided with an opening or pore for storing lubricating oil or grease, or the cage of the bearing may contain a material capable of adsorbing lubricating oil or grease, the material being, for example, phenol resin. Therefore, an appropriate amount of lubricating oil or grease can be held on the outer surface of the ball by the cage, thereby ensuring the lubricating effect and reducing the friction torque of the deep groove ball bearing.In the deep groove ball bearing shown in Fig. 5C, the cage 4 is a nylon resin cage, and the deep groove ball bearing further has a seal ring 6 for sealing grease 5. The grease 5 is filled between the outer ring 1 and the inner ring 2. In addition, the deep groove ball bearing of FIG. 5C also corresponds to the combinations of the ranges of the ratios fe and fi and the restriction angles Ae and Ai for the deep groove ball bearing according to the present invention, and also has significantly reduced friction torque.Exemplary embodiments of the bearing cage and bearing proposed by the present disclosure have been described in detail above with reference to the preferred embodiments. However, it will be apparent to those skilled in the art that various variations and modifications can be made to the above-described specific embodiments without departing from the concept of the present disclosure, and that various technical features and structures proposed by the present disclosure can be combined in various ways without departing from the scope of the present disclosure.

Claims

A grooved ball bearing (100) comprising an outer ring (1), an inner ring (2), balls (3) disposed between the outer ring and the inner ring, and a cage (4) for holding the balls, wherein the outer ring (1) has an outer ring raceway (10), the outer ring raceway defines an outer ring raceway radius (re), wherein a ratio of the outer ring raceway radius (re) to a diameter of the balls defines a first ratio (fe), and two edges (13, 14) of the outer ring raceway (10) in an axial direction define an outer ring raceway boundary angle (Ae) relative to a center (15) of an arc of the outer ring raceway (10), the inner ring (2) has an inner ring raceway (20), the inner ring raceway defines an inner ring raceway radius (ri), wherein a ratio of the inner ring raceway radius (ri) to the diameter of the balls defines a second ratio (fi), and two edges (23, 24) of the inner ring raceway (20) in the axial direction define an inner ring raceway boundary angle (Ai) relative to a center (25) of an arc of the inner ring raceway (20), wherein a range of the first ratio (fe) is 0.525 - 0.570, a range of the second ratio (fi) is 0.510 - 0.530, a range of the outer ring raceway boundary angle (Ae) is 66° - 97°, and a range of the inner ring raceway boundary angle (Ai) is 72° - 99°.The deep groove ball bearing according to claim 1, wherein the range of the first ratio is 0.530 to 0.565, the range of the second ratio is 0.515 to 0.530, the range of the outer ring raceway limitation angle is 69° to 94°, and the range of the inner ring raceway limitation angle is 76° to 96°.The deep groove ball bearing according to claim 2, wherein the range of the first ratio is 0.535 to 0.560, the range of the second ratio is 0.520 to 0.530, the range of the outer ring raceway limitation angle is 72° to 84°, and the range of the inner ring raceway limitation angle is 80° to 92°.The deep groove ball bearing according to any one of claims 1 to 3, wherein the deep groove ball bearing comprises grease.The deep groove ball bearing according to claim 4, wherein the viscosity of the grease at 40°C is less than 40 mm 2 / s.The deep groove ball bearing according to claim 5, wherein the viscosity of the grease at 40°C is less than 30 mm 2 / s.The deep groove ball bearing according to any one of claims 1 to 3, wherein the cage is made of a polymer.The deep groove ball bearing of claim 7, wherein the cage is a nylon plastic cage.The deep groove ball bearing according to claim 7, wherein the cage comprises a material capable of adsorbing lubricating oil or grease.The deep groove ball bearing according to any one of claims 1 to 3, wherein the cage is provided with an opening or pore for receiving lubricating oil or grease.

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