A retainer for ball bushings

Abstract

This utility model relates to the field of mechanical transmission technology and discloses a retainer for ball bushings, including a retainer body. The retainer body has a lubrication mechanism inside and sealing mechanisms on both its upper and lower sides. The lubrication mechanism includes multiple balls, and the retainer body has multiple ball holes circumferentially formed. The outer wall of each ball contacts the inner wall of the ball hole, and oil reservoirs are formed on the top left and right inner walls of the ball hole. In this utility model, a continuous and controllable micro-supply is achieved through the rolling of ceramic balls, thereby maintaining a stable lubricating oil film on the contact surface between the ball and the ball hole. This transforms sliding friction into efficient rolling friction, greatly reducing motion resistance and wear, and ensuring that the sensor transmission mechanism can maintain high smoothness, low noise, and high precision over a long period.

Description

Technical Field

[0001] This utility model relates to the field of mechanical transmission technology, and in particular to a retainer for ball bushings. Background Technology

[0002] Ball bushings, as a high-precision linear motion mechanism, consist of an outer sleeve, an inner sleeve, balls, and a retainer. Due to their low coefficient of friction and high motion accuracy, they are widely used in various precision sensors (such as linear displacement sensors and optical encoders) as their core guiding and transmission components. The retainer (or spacer, ball cage) is a key component of the ball bushing; its core function is to evenly separate and guide the cyclical movement of the balls. Its performance directly determines the accuracy, lifespan, and reliability of the entire bushing and even the sensor.

[0003] However, in existing technologies, the retainer pockets for ball bushings commonly used in sensors typically have smooth inner surfaces. While these pockets can accommodate the balls, they lack an effective long-term lubrication structure. The initially applied grease is easily scraped off by the balls during operation or evaporates and is lost after prolonged use, making it difficult to replenish effectively. This leads to a gradual boundary lubrication or even dry friction state between the balls and the inner wall of the pocket. Consequently, this increases motion resistance and frictional heat, accelerates wear on both the retainer and the balls, alters the ball's trajectory, introduces unpredictable errors, severely degrades the sensor's measurement accuracy and repeatability, and significantly shortens the overall lifespan of the component. Therefore, a new retainer for ball bushings is proposed to address these issues. Utility Model Content

[0004] To overcome the above shortcomings, this utility model provides a retainer for ball bushings, which aims to improve the problem of grease loss caused by the inability of existing technologies to effectively and sustainably lubricate, thus affecting motion accuracy.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: A retainer for ball bushings includes a retainer body, a lubrication mechanism is provided inside the retainer body, and a sealing mechanism is provided on both the upper and lower sides of the retainer body. The lubrication mechanism includes multiple balls, and the retainer body has multiple ball holes in its circumferential direction. The outer wall of the ball contacts the inner wall of the ball hole. Oil storage pits are formed on the inner walls of the top left and right sides of the ball hole, and the oil storage pits are filled with lubricating grease. As a further description of the above technical solution: The retainer body has a guide shaft inside, the outer wall of the guide shaft is in contact with the outer walls of the plurality of balls, and the retainer body has a shell outside, the inner wall of the shell is in contact with the outer walls of the plurality of balls. As a further description of the above technical solution: The main body of the retainer is made of polyetheretherketone, and the ball bearing is made of ceramic. As a further description of the above technical solution: The sealing mechanism includes multiple flexible sealing rings, which are fixedly connected to the inner and outer walls of both ends of the retainer body. Guide rings are fixedly connected to both the upper and lower sides of the retainer body. As a further description of the above technical solution: The retainer is annular and integrally injection molded from engineering plastic. The oil reservoir is hemispherical in shape and located in the non-primary load-bearing area on the inner surface of the ball bearing hole.

[0006] This utility model has the following beneficial effects: 1. In this utility model, the hemispherical oil reservoir located in the non-main load-bearing area of ​​the ball bearing hole can capture and store lubricating grease during assembly, and provide a continuous and controllable micro-supply through the rolling of ceramic balls during operation. This maintains a stable lubricating oil film on the contact surface between the ball and the ball bearing hole, transforming sliding friction into efficient rolling friction, greatly reducing motion resistance and wear. Furthermore, the viscosity of the grease effectively dampens the minor vibrations and impacts of the ball. Combined with the high rigidity, creep resistance, and self-lubricating properties of the PEEK material retainer body, this ensures that the sensor transmission mechanism can maintain high smoothness, low noise, and high precision over a long period of time.

[0007] 2. In this invention, the flexible sealing rings on the inner and outer walls of the retainer body form a labyrinthine path, maintaining a minimal non-contact gap with the guide shaft and the outer shell surface. This utilizes energy dissipation principles to prevent external contaminants from intruding and to prevent internal lubricant leakage. Meanwhile, the guide rings on the upper and lower sides of the retainer body form a precise clearance fit with the matching components, providing radial auxiliary support and centering guidance. During operation, the flexible sealing rings effectively block contaminants, and the guide rings constrain the retainer body to move smoothly along the axial direction, preventing swaying or jamming, thereby ensuring the stability and accuracy of the sensor's core moving components. Attached Figure Description

[0008] Figure 1 This is a perspective view of a retainer for ball bushings proposed in this utility model; Figure 2 This is a schematic diagram of the main body of a retainer for a ball bushing according to the present invention; Figure 3 for Figure 2 Enlarged view of point A in the middle; Figure 4 for Figure 2 Enlarged view of point B in the middle.

[0009] Legend: 1. Retainer body; 2. Ball bore; 3. Ball; 4. Oil reservoir; 5. Lubricating grease; 6. Guide shaft; 7. Housing; 8. Flexible sealing ring; 9. Guide ring. Detailed Implementation

[0010] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0011] Reference Figure 1 , Figure 2 and Figure 3 The present invention provides an embodiment of a ball bushing retainer, comprising a retainer body 1, the retainer body 1 being made of polyetheretherketone (PEEK), which ensures that it has excellent fatigue resistance, creep resistance and sufficient mechanical strength when subjected to cyclic stress from the balls 3. The retainer is annular and integrally injection molded from engineering plastic, providing extremely high integrity and dimensional stability. A lubrication mechanism is provided inside the retainer body 1, and sealing mechanisms are provided on both the upper and lower sides of the retainer body 1. The lubrication mechanism includes multiple balls 3 made of ceramic. The main body of the retainer has multiple ball holes 2 opening upwards around its circumference. The outer wall of the ball 3 contacts the inner wall of the ball hole 2. The core function of the ball hole 2 is to accurately accommodate and isolate each ball 3. Oil storage pits 4 are provided on the inner walls of the top left and right sides of the ball hole 2. The oil storage pits 4 are hemispherical in shape and located in the non-main load-bearing area on the inner surface of the ball hole 2. The oil storage pits 4 are filled with lubricating grease 5. The core structural function of the oil storage pit 4 is to form a reliable micro-grease reservoir. Through its specific shape and position, it can capture and store lubricating grease 5 during assembly and continuously and controllably release the lubricating medium during operation through the squeezing effect of the ball 3, achieving long-term self-lubrication, while avoiding stress concentration caused by its location in the main load-bearing area.

[0012] The retainer body 1 has a guide shaft 6 inside, and the outer wall of the guide shaft 6 contacts the outer wall of a plurality of balls 3. The retainer body 1 has a housing 7 outside, and the inner wall of the housing 7 contacts the outer wall of a plurality of balls 3. The balls 3 are precision-manufactured ceramic spheres. As the core transmission element, their function is to make precise rolling contact between the guide shaft 6 and the housing 7, converting sliding friction into rolling friction, thereby greatly reducing motion resistance. The structural function of the guide shaft 6 is to provide the inner rolling track for the balls 3. The housing 7 is an outer sleeve that houses the entire retainer, and its structural function is to provide the outer rolling track for the balls 3.

[0013] Reference Figure 1 , Figure 2 and Figure 4 The sealing mechanism includes multiple flexible sealing rings 8, which are fixedly connected to the inner and outer walls of both ends of the retainer body 1. The flexible sealing rings 8 are labyrinth-type sealing lips integrated into the ends of the retainer body 1. Their core structural function is to form a very small non-contact gap with the guide shaft 6 and the surface of the outer shell 7, constructing a long and tortuous labyrinth path. Through the energy consumption principle, it effectively blocks the intrusion of external contaminants (such as dust and water vapor) and prevents the leakage of internal lubricating grease 5. This is the key to achieving maintenance-free and long service life. Guide rings 9 are fixedly connected to the upper and lower sides of the retainer body 1. The guide rings 9 are annular structures fixed to the upper and lower sides of the retainer body 1. Their core structural function is to form a precise radial clearance fit with the inner wall of the matching component, providing radial auxiliary support and centering guidance for the retainer body 1, preventing radial sway or tilting during operation.

[0014] Working principle: During assembly, lubricating grease 5 is pre-filled into the oil reservoir 4 on the inner wall of the ball bore 2. When the guide shaft 6 in the sensor moves relative to the housing 7, it drives the ball 3 in the retainer to roll in the ball bore 2. During this process, the surface of the ball 3 periodically sweeps over and squeezes the edge of the oil reservoir 4. This squeezing action continuously and in small amounts squeezes out the lubricating grease 5 stored in the oil reservoir 4 and evenly coats it on the surface of the ball 3 and its contact surface with the ball bore 2, forming an extremely thin lubricating oil film between the moving parts. This effectively reduces the coefficient of friction and wear, and utilizes the viscous damping effect of the grease to absorb the small vibrations and impacts of the ball 3, thereby ensuring the high smoothness, low noise and long life of the sensor transmission. The flexible sealing ring 8 maintains a very small, uniform, non-contact gap with the surfaces of the guide shaft 6 and the housing 7, forming a long and tortuous gap channel. When external contaminants such as dust and moisture attempt to pass through this gap, their kinetic energy is dissipated after multiple collisions and changes in direction, thus effectively blocking them from entering. On the other hand, the guide rings 9 fixed on the upper and lower sides of the retainer body 1 maintain a precise clearance fit with the matching components. They mainly play a role in radial guidance and support during movement, constraining the retainer body 1 to move smoothly only along the axial direction, preventing it from swaying or jamming, thereby ensuring the stability and accuracy of the sensor's core moving parts.

[0015] Finally, it should be noted that the above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Although the present utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A retainer for ball bushings, comprising a retainer body (1), characterized in that: The retainer body (1) is provided with a lubrication mechanism inside, and the retainer body (1) is provided with a sealing mechanism on both the upper and lower sides. The lubrication mechanism includes multiple balls (3), and the retainer body (1) has multiple ball holes (2) in the circumferential direction. The outer wall of the ball (3) is in contact with the inner wall of the ball hole (2). Oil storage pits (4) are provided on the inner walls of the top left and right sides of the ball hole (2), and the inside of the oil storage pit (4) is filled with lubricating grease (5).

2. A retainer for ball bushings according to claim 1, characterized in that: The retainer body (1) is provided with a guide shaft (6) inside, the outer wall of the guide shaft (6) is in contact with the outer wall of the plurality of balls (3), and the retainer body (1) is provided with a shell (7) outside, the inner wall of the shell (7) is in contact with the outer wall of the plurality of balls (3).

3. A retainer for ball bushings according to claim 1, characterized in that: The material of the retainer body (1) is polyetheretherketone (PEEK), and the material of the ball (3) is ceramic.

4. A retainer for ball bushings according to claim 1, characterized in that: The sealing mechanism includes multiple flexible sealing rings (8), which are fixedly connected to the inner and outer walls of both ends of the retainer body (1). Guide rings (9) are fixedly connected to both the upper and lower sides of the retainer body (1).

5. A retainer for ball bushings according to claim 1, characterized in that: The retainer (1) is annular and integrally injection molded from engineering plastic. The oil storage pit (4) is hemispherical in shape and is located in the non-main load-bearing area on the inner surface of the ball hole (2).

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