Inner and outer double flow guide type deep groove ball bearing retainer for molecular pump

Abstract

A cage for a deep groove ball bearing used in molecular pumps features internal and external dual-flow structures with different pathways on its inner and outer sides. Both structures ensure lubricating oil flows through the cage to the rolling elements, effectively achieving reliable oil delivery and stable lubrication during bearing operation. Simultaneously, the cage body has an inner flange-shaped oil-blocking structure at its inner diameter end. After bearing assembly, this structure not only forms a barrier between the cage and the inner ring, preventing foreign matter from entering the bearing and causing failure, but also effectively prevents lubricating oil loss within the working area. This maintains lubricating oil within the bearing's working area, ensuring continuous and effective lubrication. This design effectively meets the operating requirements of deep groove ball bearings for molecular pumps, significantly extending their service life.

Description

Technical Field

[0001] This invention relates to the field of deep groove ball bearings for molecular pumps, specifically a cage for a deep groove ball bearing with internal and external double flow guides for molecular pumps. Background Technology

[0002] Deep groove ball bearings for molecular pumps are used in vacuum environments and are characterized by high speed, long life, and high reliability. Related research indicates that the main failure of molecular pump bearings is burn-out. Analysis shows that the primary cause is the inability of the bearing to effectively dissipate heat in a vacuum environment. Furthermore, the high-speed operation of the bearing causes the temperature at the contact points between the rolling elements and the bearing rings to rise, making it difficult for the lubricating medium to form an effective lubricating film on the bearing surface. Providing sufficient lubricating oil and ensuring its distribution to all parts of the bearing is crucial for achieving optimal cooling. Currently, common bearing oil lubrication methods include oil bath lubrication, drip lubrication, oil rope lubrication, pressure circulation lubrication, oil mist lubrication, oil spray lubrication, and oil-air lubrication. While these methods provide some cooling effect, they do not fully meet the operating requirements of molecular pump bearings.

[0003] The lubrication method for turbomolecular pump bearings is as follows: an oil-soaked felt containing lubricating oil is placed next to the inner ring of the bearing, rotating with the pump shaft. Under the action of high-speed centrifugal force, the lubricating oil in the felt is thrown out onto the cage, and then carried by the cage into the working area of ​​the bearing. Due to the high-speed operation of turbomolecular pump bearings and the special nature of their lubrication method, ordinary deep groove ball bearing cages simply cannot meet the requirements for a good lubrication structure.

[0004] Therefore, improving the structure of the cage of deep groove ball bearings for molecular pumps to better achieve long-term effective lubrication of the rolling elements inside the bearings is of great significance for extending the service life and reducing the cost of deep groove ball bearings for molecular pumps. Summary of the Invention

[0005] The technical objective of this invention is to provide a molecular pump deep groove ball bearing cage with a simple and reasonable structure, featuring an inner and outer double-flow structure. The inner flange and spiral oil guide groove on the inner diameter side of the cage body can form a micro-circulation structure for lubricating oil with the main oil core, thereby achieving long-term effective lubrication of the rolling elements in the pocket. The use of this cage can better meet the operating conditions of deep groove ball bearings for molecular pumps and effectively extend the service life of deep groove ball bearings for molecular pumps.

[0006] To solve the above-mentioned technical problems, the present invention adopts the following technical solution: a deep groove ball bearing cage for a molecular pump with internal and external double flow guides, including a cage body, the outer diameter surface of which is a conical structure, a plurality of pockets for accommodating rolling elements are uniformly opened circumferentially at the small diameter end of the conical cage body, and a flow guide slope is provided at the large diameter end of the conical cage body from the outer diameter side to the inner diameter side, and a radial platform is provided at the top of the flow guide slope extending towards the inner diameter side; The inner diameter surface of the cage body consists of a first cylindrical surface, a first conical surface, a second cylindrical surface, and a second conical surface, which are sequentially connected from the large diameter end to the small diameter end. The first cylindrical surface and the second cylindrical surface are both parallel to the central axis of the cage body. The first conical surface and the second conical surface are both inclined towards the outer diameter direction of the cage body. The tops of the first conical surface, the first cylindrical surface, the radial platform, and the guide slope together form an inner flange-shaped oil-blocking structure at the end of the inner diameter side of the cage body. The pocket is opened on the second conical surface. A spiral oil guide groove is also opened on the inner diameter surface of the cage body. The spiral oil guide groove starts from the point where the second cylindrical surface connects to the first conical surface and ends at the bottom end of the pocket on the second conical surface. The width and depth of the spiral oil guide groove decrease continuously from the starting end to the ending end, so that the width and depth of the spiral oil guide groove on the longitudinal section of the cage body decrease in an arithmetic progression. The lubricating oil in the deep groove ball bearing can enter the pocket through the first guiding lubrication path formed by the radial platform, the guide slope and the outer diameter surface of the cage body, or through the second guiding lubrication path formed by the first cylindrical surface, the first conical surface, the second cylindrical surface, the spiral oil guide groove and the second conical surface, so as to achieve lubrication of the rolling elements in the pocket.

[0007] Furthermore, the pockets are straight pockets, and the number of pockets on the cage body is odd.

[0008] Furthermore, the angle between the guide slope and the central axis of the cage body is 60-80°, and the angle between the outer diameter surface of the cage body and its central axis is 2-3°.

[0009] Furthermore, each pocket extends to the end face of the cage body and has a locking opening, the size of which is 0.6-0.9 times the diameter of the rolling element, and the diameter of the pocket is 1.01-1.03 times the diameter of the rolling element.

[0010] Furthermore, the radial platform is positioned perpendicular to the central axis of the cage body.

[0011] Furthermore, the spiral oil guide groove has a constant pitch structure.

[0012] Furthermore, the cross-section of the spiral oil guide groove is a right-angled isosceles triangle structure.

[0013] Furthermore, the cross-section of the spiral oil guide groove is a right-angled isosceles triangle with a rounded apex.

[0014] Furthermore, the angle between the first conical surface and the central axis of the cage body is 20-50°, and the angle between the second conical surface and the central axis of the cage body is 4-6°.

[0015] A deep groove ball bearing for a molecular pump includes an outer ring, an inner ring, and rolling elements. A cage body is assembled between the outer ring and the inner ring. The inner flange-shaped oil-blocking structure on the cage body can cooperate with the outer wall surface of the inner ring to retain the lubricating oil on the inner diameter side of the cage body and prevent foreign objects from entering.

[0016] Beneficial effects: 1. The present invention provides a deep groove ball bearing cage for a molecular pump with internal and external double-flow guiding structure. This cage has a simple structure and ingenious design. Compared to existing technologies, this application features internal and external double-flow guiding structures with different paths on the inner and outer sides of the cage body. Both double-flow guiding structures can ensure that lubricating oil flows through the cage to the rolling elements, effectively achieving reliable delivery and stable lubrication of lubricating oil to the working area during bearing operation. Simultaneously, the cage body has an inner flange-shaped oil-blocking structure at its inner diameter end. After bearing assembly, this inner flange-shaped oil-blocking structure not only forms a barrier between itself and the inner ring of the bearing, preventing foreign matter from entering the bearing and causing failure, but also effectively avoids lubricating oil loss in the working area, ensuring a certain degree of lubrication retention in the bearing's working area and guaranteeing continuous and effective lubrication. This results in good practical performance.

[0017] 2. The present invention provides a double-flow deep groove ball bearing cage for molecular pumps, which has two significant structural advantages: First, an inner flange-shaped oil-blocking structure is provided on the inner diameter side; second, a spiral oil-guiding groove is formed on the inner diameter surface of the cage body. The inner flange and spiral oil-guiding groove on the inner diameter side of the cage body can form a micro-circulation structure for lubricating oil with the main oil felt, so as to achieve long-term effective lubrication of the rolling elements in the pocket. The use of this cage can better meet the operating conditions of deep groove ball bearings for molecular pumps and effectively extend the service life of deep groove ball bearings for molecular pumps.

[0018] 3. The present invention provides a deep groove ball bearing for a molecular pump, wherein the cage has a flanged structure, the outer diameter surface of the cage body is a sloping conical structure at an angle to the axial direction, and the inner diameter surface of the cage body employs a spiral oil guide groove with an arithmetic progression decreasing in number. These cage structures can better ensure that lubricating oil can enter the bearing working area in a timely and appropriate manner when the turbomolecular pump rotates at high speed, thereby obtaining good lubrication. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the structure of the deep groove ball bearing for the molecular pump of the present invention; Figure 2 This is a schematic diagram of the cage structure of the present invention; Figure 3 This is a side view of the retainer of the present invention; Figure 4 This is a partial cross-sectional view of the cage of the present invention; Reference numerals: 1. Cage body; 2. Bearing outer ring; 3. Bearing inner ring; 4. Rolling element; 11. Outer diameter surface; 12. Second conical surface; 13. Pocket; 14. Locking hole; 15. Second cylindrical surface; 16. Spiral oil guide groove; 17. First conical surface; 18. Guide slope; 19. Radial platform; 20. First cylindrical surface. Detailed Implementation

[0020] To make the technical problems, solutions, and effects of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the invention.

[0021] In the description of this invention, it should be understood that the terms "upper," "lower," "front," "rear," "left," "right," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the appendix. Figure 1 This description is provided for the convenience of describing the invention and for the purpose of simplifying the description, and is not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention.

[0022] like Figure 1-4 As shown, a deep groove ball bearing cage for a molecular pump with internal and external double-flow guide type according to the present invention includes a cage body 1. The outer diameter surface 11 of the cage body 1 has a conical structure, and the angle between the outer diameter surface 11 and its central axis is 2-3°. Multiple pockets 13 for accommodating rolling elements 4 are uniformly formed circumferentially at the small diameter end of the conical cage body 1. The pockets 13 are straight pockets, and each pocket 13 has a locking opening 14 at a position extending to the end face of the cage body 11. The size of the locking opening 14 is... The diameter of the rolling element 4 is 0.6-0.9 times that of the rolling element 4, and the diameter of the pocket 13 is 1.01-1.03 times that of the rolling element 4. The number of pockets 13 on the cage body 1 is odd. A guide slope 18 is provided at the large diameter end of the conical cage body 1 from the outer diameter side to the inner diameter side. The angle between the guide slope 18 and the central axis of the cage body 1 is 60-80°. The top of the guide slope 18 is also provided with a radial platform 19 that is perpendicular to the central axis of the cage body 1 and extends towards the inner diameter side. The inner diameter surfaces of the cage body 1 are sequentially joined by a first cylindrical surface 20, a first conical surface 17, a second cylindrical surface 15, and a second conical surface 12 from the large diameter end to the small diameter end. The angle between the first conical surface 17 and the central axis of the cage body 1 is 20-50°, and the angle between the second conical surface 12 and the central axis of the cage body 1 is 4-6°. The first cylindrical surface 20 and the second cylindrical surface 15 are both parallel to the central axis of the cage body 1. The first conical surface 17 and the second conical surface 12 are both inclined towards the outer diameter direction of the cage body 1, so that the tops of the first conical surface 17, the first cylindrical surface 20, the radial platform 19, and the guide slope 18 together form an inner flange-shaped oil-blocking structure at the end of the cage body 1 on the inner diameter side. The pocket 1... 3. A spiral oil guide groove 16 is also provided on the inner diameter surface of the cage body 1 on the second conical surface 12. The spiral oil guide groove 16 starts from the connection between the second cylindrical surface 15 and the first conical surface 17 and ends at the bottom of the pocket 13 on the second conical surface 12. The width and depth of the spiral oil guide groove 16 decrease continuously from the starting end to the ending end, so that the width and depth of the spiral oil guide groove 16 on the longitudinal section of the cage body 1 decrease in an arithmetic sequence. The spiral oil guide groove 16 has a constant pitch structure and the cross section of the spiral oil guide groove 16 has a right isosceles triangle structure with a rounded apex. The lubricating oil in the deep groove ball bearing can enter the pocket 13 through the first lubrication path formed by the radial platform 19, the guide slope 18 and the outer diameter surface 11 of the cage body 1, or it can enter the pocket 13 through the second lubrication path formed by the first cylindrical surface 20, the first conical surface 17, the second cylindrical surface 15, the spiral oil guide groove 16 and the second conical surface 12, so as to achieve lubrication of the rolling elements 4 in the pocket 13.

[0023] A deep groove ball bearing for a molecular pump includes an outer ring 2, an inner ring 3, and rolling elements 4. A cage body 1 is assembled between the outer ring 2 and the inner ring 3. The inner flange-shaped oil-blocking structure on the cage body 1 can cooperate with the outer wall surface of the inner ring 3 to retain the lubricating oil on the inner diameter side of the cage body 1 and prevent the intrusion of foreign objects.

[0024] The main structural features of the deep groove ball bearing cage for a molecular pump with internal and external double flow guides of the present invention are as follows: First, an inner flange-shaped oil-blocking structure is provided on the inner diameter side; second, a spiral oil-guiding groove is opened on the inner diameter surface of the cage body, which facilitates the formation of a micro-circulation structure of lubricating oil with the main machine oil felt, thus well meeting the operating conditions requirements of the molecular pump bearing.

[0025] In this invention, the pockets are straight pockets designed to accommodate rolling elements. The pockets are evenly distributed along the circumference of the cage, with an odd number of pockets being more numerous than an even number. The straight pockets are locked to the rolling elements by a locking mechanism. The smaller size of the locking mechanism helps improve the stability of the bearing operation.

[0026] The end face of the large-diameter end of the cage body described in this invention adopts a flow-guiding structure that combines a small platform and a large inclined surface, and the inner flange on the inner diameter side of the cage body adopts a flow-guiding structure that combines a small platform and a small inclined surface. Both of these can satisfy the requirement that lubricating oil flows through the cage to the rolling elements.

[0027] The outer diameter surface of the cage body described in this invention has a sloping conical structure with a certain angle to the cage axis, and the diameter is larger at the part away from the rolling element pocket and smaller at the part closer to the rolling element pocket.

[0028] The inner diameter surface of the cage body described in this invention adopts a structure combining a cylinder and a cone. A spiral oil guide groove is machined starting at the junction of the flange and the cylindrical surface. This spiral oil guide groove has a constant pitch structure, and its cross-section presents a right-angled isosceles triangle without a apex angle. From the end away from the rolling element pocket to the end near the rolling element pocket, the width and depth of the spiral oil guide groove decrease in an arithmetic progression, extending to the pocket where it is truncated.

[0029] Compared to existing technologies, the turbomolecular pump bearing of this invention features a cage with an oil-guiding function. Its outer diameter surface is a sloping conical structure with an angled section along the cage axis, while the inner diameter surface employs spiral oil-guiding grooves arranged in an arithmetic progression of small numbers. These cage structures better ensure that lubricating oil can enter the bearing's working area promptly and in appropriate amounts during high-speed rotation of the turbomolecular pump, thereby achieving excellent lubrication.

[0030] Example 1 like Figure 1 As shown, a deep groove ball bearing for a molecular pump includes a cage body 1, an outer ring 2, an inner ring 3, and rolling elements 4. One end of the cage body 1 has an odd number of pockets 13 for accommodating the rolling elements 3, and the pockets 13 are evenly arranged circumferentially along the end face of the cage body 1. The pockets 13 are straight pockets. The end face of the cage body 1 opposite to the pockets 13 adopts a flow-guiding structure combining a small platform and a large inclined surface, which consists of a flow-guiding inclined surface 18 and a radial platform 19. The inner flange on the inner diameter side of the cage body adopts a flow-guiding structure combining a small platform and a small inclined surface, which consists of a first cylindrical surface 20 and a first conical surface 21.

[0031] The end face of the cage body away from the pocket in this invention adopts a flow-guiding structure combining a small platform and a large inclined plane, and the inner flange on the inner diameter side of the cage body also adopts a flow-guiding structure combining a small platform and a small inclined plane. The lubricating oil enters the pocket in two paths: one path follows the outer surface of the cage, enters the flow-guiding structure formed by the combination of the small platform and the large inclined plane, and then enters the pocket through the outer conical surface of the cage; the other path passes through the inner surface of the cage, follows the flow-guiding structure formed by the combination of the small platform and the small inclined plane, and enters the pocket.

[0032] The cage inner diameter surface of the present invention adopts a structure combining a cylinder and a cone, namely a second cylindrical surface 15 and a second conical surface 12, where the second cylindrical surface 15 is cylindrical and the second conical surface 12 is conical. The second cylindrical surface 15 provides a machining reference for the cage end face and outer diameter surface, while the second conical surface 12 provides a lubricating oil guide, making it easier for the lubricating oil to enter the pocket. A spiral oil guide groove 16 is machined at the junction of the inner flange of the cage and the second cylindrical surface 15. This spiral oil guide groove 16 has a constant pitch structure, and its cross-section presents a right-angled isosceles triangle structure without a vertex angle. From the end away from the pocket to the end near the pocket, the width and depth of the spiral oil guide groove 16 decrease in an arithmetic progression, extending to the pocket where it is truncated.

[0033] Specifically, the spiral oil guide groove 16 has an oil guiding function. The lubricating oil enters the area where the rolling element 4 is located through the spiral oil guide groove 16, ensuring that the lubricating oil can enter the bearing working area in a timely and appropriate manner when the turbomolecular pump is rotating at high speed.

[0034] Each pocket 13 extends to the end face of the cage body 1 and has a locking slot 14. The size of the locking slot 14 is designed to prevent jamming at high temperatures; the smaller size of the locking slot helps improve the stability of the bearing operation. The number of pockets 13 is equal to the number of rolling elements 3, and the diameter of the pocket 13 is 1.01-1.03 times the diameter of the rolling element 4. The locking slot 14 is smaller than the size of the rolling element 4 to ensure that the rolling element 4 does not fall off during bearing use, and the size of the pocket 13 is slightly larger than the rolling element 4 to accommodate the rolling element 4.

[0035] The outer diameter surface 11 of the cage body 1 of the present invention has an angle of 2-3° with the axis of the cage body 1, and the diameter is slightly larger at the part away from the rolling element pocket and slightly smaller at the part closer to the rolling element pocket. The second conical surface 12 at the inner diameter has an angle of about 5° with the axis of the cage body 1.

[0036] Compared to existing technologies, this invention provides a cage structure for deep groove ball bearings used in molecular pumps. The cage has a flanged structure, and its outer edge is a sloping conical structure at an angle to the axial direction. The inner diameter surface of the cage employs spiral oil guide grooves arranged in an arithmetic progression of small numbers. This cage structure better ensures that lubricating oil can enter the bearing working area in a timely and appropriate manner during high-speed rotation of the turbomolecular pump, thereby achieving good lubrication. This provides a guarantee for the later design and mass production of vacuum molecular pump bearings 624, 607, and 608.

[0037] Specifically, after the bearing is assembled, a barrier structure is formed between the inner flange 17 of the cage and the inner ring 3 of the bearing to prevent foreign objects from entering the bearing and causing bearing failure. At the same time, it ensures that the lubricating oil has a certain retention in the bearing working area and guarantees effective lubrication in the bearing working area.

[0038] Finally, it should be noted that the above description is merely a preferred embodiment of the present invention and is not intended to limit the entire scope of the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still make formal modifications to the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. All formal modifications and equivalent substitutions made within the scope of the concept and teaching of the present invention should be included within the scope of protection of the present invention.

Claims

1. A cage for a deep groove ball bearing with internal and external double flow guides for a molecular pump, comprising a cage body (1), wherein the outer diameter surface (11) of the cage body (1) is a conical structure, and a plurality of pockets (13) for accommodating rolling elements (4) are uniformly opened circumferentially at the small diameter end of the conical cage body (1), characterized in that: A flow guide slope (18) is provided at the large diameter end of the conical cage body (1) from the outer diameter side to the inner diameter side, and a radial platform (19) is provided at the top of the flow guide slope (18) extending towards the inner diameter side. The inner diameter surfaces of the cage body (1) are sequentially joined by a first cylindrical surface (20), a first conical surface (17), a second cylindrical surface (15), and a second conical surface (12) from the large diameter end to the small diameter end. The first cylindrical surface (20) and the second cylindrical surface (15) are both parallel to the central axis of the cage body (1), while the first conical surface (17) and the second conical surface (12) are both inclined towards the outer diameter of the cage body (1). This causes the tops of the first conical surface (17), the first cylindrical surface (20), the radial platform (19), and the guide slope (18) to meet together on the cage body (1). The end assembly on the inner diameter side forms an inner flange-shaped oil-blocking structure. The pocket (13) is opened on the second conical surface (12). A spiral oil guide groove (16) is also opened on the inner diameter surface of the cage body (1). The spiral oil guide groove (16) starts from the connection between the second cylindrical surface (15) and the first conical surface (17) and ends at the bottom of the pocket (13) on the second conical surface (12). The width and depth of the spiral oil guide groove (16) decrease continuously from the starting end to the ending end, so that the width and depth of the spiral oil guide groove (16) on the longitudinal section of the cage body (1) decrease in an arithmetic sequence. The lubricating oil in the deep groove ball bearing can enter the pocket (13) through the first guiding lubrication path formed by the radial platform (19), the guide slope (18) and the outer diameter surface (11) of the cage body (1), or it can enter the pocket (13) through the second guiding lubrication path formed by the first cylindrical surface (20), the first conical surface (17), the second cylindrical surface (15), the spiral oil guide groove (16) and the second conical surface (12), so as to achieve lubrication of the rolling elements (4) in the pocket (13).

2. The cage for a deep groove ball bearing with internal and external double flow guides for a molecular pump according to claim 1, characterized in that: The pocket (13) is a straight pocket, and the number of pockets (13) on the cage body (1) is an odd number.

3. The cage for a deep groove ball bearing with internal and external double flow guides for a molecular pump according to claim 1, characterized in that: The angle between the guide slope (18) and the central axis of the cage body (1) is 60-80°, and the angle between the outer diameter surface (11) of the cage body (1) and its central axis is 2-3°.

4. The cage for a deep groove ball bearing with internal and external double flow guides for a molecular pump according to claim 1, characterized in that: Each pocket (13) extends to the end face of the cage body (1) and has a locking opening (14), the size of which is 0.6-0.9 times the diameter of the rolling element (4), and the diameter of the pocket (13) is 1.01-1.03 times the diameter of the rolling element (4).

5. The cage for a deep groove ball bearing with internal and external double flow guides for a molecular pump according to claim 1, characterized in that: The radial platform (19) is set perpendicular to the central axis of the cage body (1).

6. The cage for a deep groove ball bearing with internal and external double flow guides for a molecular pump according to claim 1, characterized in that: The spiral oil guide groove (16) has an equal pitch structure.

7. A deep groove ball bearing cage for a molecular pump with internal and external double-flow guides as described in claim 1 or 6, characterized in that: The cross-section of the spiral oil guide groove (16) is a right-angled isosceles triangle.

8. The cage for a deep groove ball bearing with internal and external double flow guides for a molecular pump according to claim 7, characterized in that: The cross-section of the spiral oil guide groove (16) is a right-angled isosceles triangle with a rounded apex.

9. The cage for a deep groove ball bearing with internal and external double flow guides for a molecular pump according to claim 1, characterized in that: The angle between the first conical surface (17) and the central axis of the cage body (1) is 20-50°, and the angle between the second conical surface (12) and the central axis of the cage body (1) is 4-6°.

10. A deep groove ball bearing for a molecular pump comprising the cage of claim 1, comprising an outer ring (2), an inner ring (3), and rolling elements (4), characterized in that: A cage body (1) is assembled between the outer ring (2) and the inner ring (3) of the bearing. The inner flange-shaped oil-blocking structure on the cage body (1) can cooperate with the outer wall surface of the inner ring (3) of the bearing to retain the lubricating oil on the inner diameter side of the cage body (1) and prevent foreign objects from entering.

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