A self-lubricating structure and method for ball screws used in high-temperature irradiated water environments

Abstract

This invention discloses a self-lubricating structure and method for ball screws used in high-temperature irradiated water environments, comprising: a screw, a nut, self-lubricating balls, working balls, and a reversing device; the screw passes through the nut, and multiple turns of self-lubricating balls and working balls are arranged between the nut and the screw. The self-lubricating balls and working balls adopt an internal circulation motion, and each turn of the self-lubricating balls and working balls returns to the raceway through the reversing device. Adjacent turns of self-lubricating balls and working balls circulate relatively independently; the self-lubricating balls are located at the end of the nut away from the force point of the screw. By incorporating self-lubricating balls with radiation resistance, the problem of lubrication failure due to deterioration of the lubrication method of ball screws in high-irradiated water environments is solved.

Description

Technical Field

[0001] This invention belongs to the field of ball screw technology, specifically relating to a self-lubricating structure and method for ball screws used in high-temperature irradiated water environments. Background Technology

[0002] The statements in this section are merely background information related to the present invention and do not necessarily constitute prior art.

[0003] A ball screw is a precision transmission device that converts rotary motion into linear motion or torque into axial force. Poor lubrication can lead to increased friction, localized temperature rise, decreased accuracy, and even shortened screw life.

[0004] Traditional lubrication methods mainly include grease lubrication and solid lubricants. Grease lubrication is achieved by injecting lubricating oil into the raceway through an oil reservoir inside the nut, thus lubricating the balls and raceway. Alternatively, solid lubricants are embedded in the internal threads of the nut, forming an oil film or powder lubrication layer under frictional heat. However, while these methods perform well under normal conditions, they are insufficient in extreme environments such as nuclear reactors and deep-sea equipment environments, including high temperature, high pressure, and high radiation. Conventional greases are prone to oxidation and decomposition, and solid lubricants have unstable coefficients of friction and insufficient wear resistance, oxidation resistance, and radiation resistance. Furthermore, harsh environments accelerate the deterioration of ball surface lubrication, leading to screw failure. Summary of the Invention

[0005] To address the aforementioned problems, this invention provides a self-lubricating structure and method for ball screws used in high-temperature irradiated water environments, solving the problem that the lubrication method of ball screws in high-temperature, high-pressure, and high-irradiation water environments is prone to deterioration and lubrication failure.

[0006] To achieve the above objectives, the present invention is implemented through the following technical solution: In a first aspect, the present invention provides a ball screw self-lubricating structure for use in high-temperature water irradiation environments, comprising: a screw, a nut, self-lubricating balls, working balls, and a reversing device; the screw passes through the nut, and multiple turns of self-lubricating balls and working balls are arranged between the nut and the screw, the self-lubricating balls and working balls adopt an internal circulation motion mode, and each turn of self-lubricating balls and working balls returns to the raceway through the reversing device, and adjacent turns of self-lubricating balls and working balls circulate relatively independently; the self-lubricating balls are located at the end of the nut away from the force point of the screw.

[0007] As a further implementation, the number of working balls is greater than the number of self-lubricating balls, and at least one working ball is provided between the self-lubricating ball and the end face of the nut, with each working ball and the self-lubricating ball arranged at intervals or adjacent to each other.

[0008] As a further implementation, the working ball has at least two revolutions, and the self-lubricating ball has at least one revolution.

[0009] As a further implementation, the reverser is embedded inside the nut and fixed by a fixing device. The fixing device is threadedly connected to the nut, and the end of the fixing device is provided with an internal hexagon blind hole.

[0010] As a further implementation, there are multiple reversers, which are evenly distributed along the axial direction of the nut. The projections of the multiple reversers on the cross-section of the nut are evenly distributed circumferentially to avoid interference between reversers of adjacent turns.

[0011] As a further implementation, the lead of the first helical groove on the outer side of the lead screw is equal to the lead of the second helical groove on the inner side of the nut.

[0012] As a further implementation, the radius of the self-lubricating ball is smaller than the radius of the working ball, so that the load between the screw and the nut is borne by the working ball, thus avoiding the situation where the self-lubricating ball wears out too quickly.

[0013] As a further implementation, the self-lubricating ball is made of a solid lubricant and a metal alloy matrix, wherein the solid lubricant is uniformly distributed in the metal alloy matrix.

[0014] As a further implementation, the solid lubricant is made of one or more materials selected from molybdenum disulfide, graphite, soft metal, metal oxide, or rare earth compound and distributed in a metal alloy matrix; the metal alloy matrix is ​​made of one or more alloys selected from iron-based, copper-based, nickel-based, cobalt-based, and refractory metal-based materials.

[0015] Secondly, the present invention also provides a lubrication method for a self-lubricating ball screw structure used in a high-temperature irradiated water environment, comprising: In a high-temperature irradiated water environment, when the ball screw rotates, the self-lubricating balls and the working balls circulate relatively independently each revolution under the action of the reverser. When the self-lubricating balls roll in the first and second helical grooves, the solid lubricant falls off from the metal alloy matrix. Under the action of high-temperature water, the solid lubricant is evenly diffused in the first and second helical grooves and adsorbed and distributed on the surface of the first and second helical grooves, forming a lubricating film that lubricates the working balls.

[0016] Compared with the prior art, the advantages and positive effects of this invention are: The present invention incorporates multiple rings of self-lubricating balls and working balls between the nut and the lead screw. The working balls bear the load of the ball screw, while the self-lubricating balls disperse their solid lubricant between the nut and the lead screw raceway or helical groove. Both the self-lubricating balls and the working balls return to the raceway via a reversing device. Adjacent rings of self-lubricating balls and working balls circulate relatively independently, allowing for diverse arrangement configurations. Since the ball screw is exposed to a high-temperature irradiated water environment, the solid lubricant in the self-lubricating balls is effectively and evenly dispersed. Compared to traditional lead screw lubrication methods, the solid lubricant in the self-lubricating balls is evenly dispersed in water and does not deposit at the bottom of the ball raceway grooves. Placing the self-lubricating balls at the end of the nut furthest from the lead screw's stress point effectively prevents excessive wear of the self-lubricating balls, thus reducing the lifespan of the ball screw. If the lead screw is stressed at both ends, the self-lubricating balls should be positioned in the middle of the nut, with the working balls positioned at both ends, effectively preventing excessive wear of the self-lubricating bearings.

[0017] In this invention, the number of working balls is greater than the number of self-lubricating balls, with at least two working balls and at least one self-lubricating ball. This ensures that working balls are provided at both ends of the nut, guaranteeing that the main transmission load is borne by high-strength conventional balls. Since the radius of the working balls is larger than that of the self-lubricating balls, providing working balls at both ends can effectively improve the rotational stability between the nut and the lead screw. The self-lubricating balls provide lubrication in the middle of the nut. The self-lubricating balls and working balls are arranged alternately or adjacently, which can be flexibly adjusted according to actual lubrication requirements or space constraints. In special working conditions such as short lead screws, an alternate arrangement is used to enhance local lubrication.

[0018] Because the rolling grooves of the self-lubricating balls or working balls are spiral-shaped, and the self-lubricating balls or working balls form a closed loop through the reversers, there is a turning space of a set angle for each turn of the self-lubricating balls or working balls at the reversers. By having multiple reversers evenly distributed along the axial direction of the nut, and the projection of the multiple reversers on the cross-section of the nut being evenly distributed circumferentially, the turning space can be dispersed along the circumference of the nut to avoid interference between the reversers rolling adjacent turns.

[0019] The self-lubricating ball bearing of this invention is made of a solid lubricant and a metal alloy matrix. The solid lubricant is uniformly distributed in the metal matrix, and there is essentially no difference between the surface and the interior of the material. The solid lubricant, which is uniformly distributed inside the metal matrix, is gradually squeezed out to the surface under the action of extrusion and deformation. Under the repeated action of friction, a complete and continuous lubricating film is formed. Attached Figure Description

[0020] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0021] Figure 1 This is a schematic diagram of the self-lubricating ball screw structure of the present invention; Figure 2 For the present invention Figure 1 Cross-sectional view at point AA; Figure 3 For the present invention Figure 1 Cross-sectional view at point BB; Figure 4 For the present invention Figure 1 Cross-sectional view at point C; Figure 5 For the present invention Figure 1 Cross-sectional view at point DD.

[0022] In the diagram: 1. Lead screw; 2. Nut; 3. Reversing device; 4. Self-lubricating ball; 5. Working ball. Detailed Implementation

[0023] It should be noted that the following detailed description is illustrative and intended to provide further explanation of the invention. Unless otherwise specified, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0024] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention. As used herein, unless otherwise expressly indicated by the invention, the singular form is also intended to include the plural form. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof. Example 1 This embodiment provides a self-lubricating ball screw structure for use in high-temperature irradiated water environments, such as... Figures 1-5As shown, the ball screw comprises: a lead screw 1, a nut 2, self-lubricating balls 4, working balls 5, and a reversing device 3. The lead screw 1 passes through the nut 2. Multiple turns of self-lubricating balls 4 and working balls 5 are arranged between the nut 2 and the lead screw 1. The working balls 5 primarily bear the load of the ball screw. The self-lubricating balls 4 disperse their solid lubricant between the nut 2 and the lead screw 1. The self-lubricating balls 4 and working balls 5 adopt an internal circulation motion. Each turn of the self-lubricating balls 4 and working balls 5 returns to the raceway via the reversing device 3. Adjacent turns of the self-lubricating balls 4 and working balls 5 circulate relatively independently, allowing for diverse arrangement of the self-lubricating balls 4 and working balls 5. The self-lubricating balls 4 and working balls 5 can be arranged alternately or adjacently to improve the self-lubricating effect of the ball screw. Furthermore, since the ball screw is in a high-temperature irradiated water environment, the solid lubricant of the self-lubricating balls 4 can be effectively and evenly dispersed, improving the lubrication effect of the ball screw. Compared to traditional ball screw lubrication, the solid lubricant in the self-lubricating balls 4 can be evenly dispersed in water and will not settle at the bottom of the ball raceway grooves. It also avoids lubricant failure due to radiation, as traditional lubricants have very weak radiation resistance in nuclear facility environments and are prone to failure. The self-lubricating balls 4 are positioned at the end of the nut 2 away from the stress point of the ball screw 1. Since the balls closest to the stress point experience the greatest stress during the rotation of the ball screw, and the stress decreases sequentially towards the stress point, positioning the self-lubricating balls 4 at the end of the nut 2 away from the stress point of the ball screw 1 effectively prevents excessive wear of the self-lubricating balls, thus reducing the service life of the ball screw. This configuration is mainly suitable for ball screw 1 with stress at one end. If the ball screw 1 is stressed at both ends, i.e., when the ball screw 1 bears load in both forward and reverse rotation, the self-lubricating balls 4 need to be positioned in the middle of the nut 2, and the working balls 5 should be positioned at both ends of the nut 2 to effectively prevent excessive wear of the self-lubricating bearings.

[0025] As a further implementation, the number of turns of the working ball 5 is greater than the number of turns of the self-lubricating ball 4, ensuring that the main transmission load is borne by the high-strength conventional ball, while the self-lubricating ball 4 helps to reduce friction. The two work together to reduce motion resistance. At least one turn of the working ball 5 is provided between the self-lubricating ball 4 and the end face of the nut 2. The self-lubricating ball 4 and the working ball 5 are arranged at intervals or adjacent to each other, which can be flexibly adjusted according to actual lubrication needs or space constraints. In special working conditions such as when the lead screw 1 is short, the interval arrangement is adopted to enhance local lubrication.

[0026] As a further implementation, the working ball 5 has at least two turns, and the self-lubricating ball 4 has at least one turn. In this embodiment, the working ball 5 has three turns, and the self-lubricating ball 4 has one turn. The nut 2 has two turns at the end near the force point of the lead screw 1 and one turn at the end away from the force point of the lead screw 1, so that both ends of the nut 2 are provided with working balls 5. Since the radius of the working ball 5 is larger than the radius of the self-lubricating ball 4, the working balls 5 at both ends can effectively improve the rotational stability between the nut 2 and the lead screw 1. The self-lubricating ball 4 provides lubrication in the middle of the nut 2.

[0027] As a further implementation, the reverser 3 is embedded inside the nut 2 and fixed by a fixing device. The fixing device is threadedly connected to the nut 2, and the end of the fixing device is provided with an internal hexagon blind hole. The mounting hole of the fixing device can be used to add self-lubricating balls 4 and working balls 5 between the nut 2 and the lead screw 1. At the same time, the fixing device presses the reverser 3 to reverse the direction of the self-lubricating balls 4 and working balls 5.

[0028] As a further implementation, there are multiple reversers 3, which are evenly distributed along the axial direction of the nut 2. The projections of the multiple reversers 3 on the cross-section of the nut 2 are evenly distributed circumferentially to avoid interference between adjacent turns of the reversers 3. Since the rolling grooves of the self-lubricating balls 4 or working balls 5 are helical, the self-lubricating balls 4 or working balls 5 form a closed loop through the reversers 3, resulting in a turning space of a set angle for each turn of the self-lubricating balls 4 or working balls 5 at the reversers 3. At the same time, the lead of the first helical groove on the outer surface of the lead screw 1 and the lead of the second helical groove on the inner surface of the nut 2 are equal, and each turn of the self-lubricating balls 4 or working balls 5 is adjacent. The evenly distributed circumferential projections of the multiple reversers 3 on the cross-section of the nut 2 can disperse the turning space along the circumference of the nut 2 to avoid interference between adjacent turns of the balls.

[0029] As a further implementation, the lead of the first helical groove on the outer side of the lead screw 1 is equal to the lead of the second helical groove on the inner side of the nut 2; the radius of curvature of the first helical groove is slightly larger than the radius of the self-lubricating ball 4 and the working ball 5, and the radius of curvature of the second helical groove is equal to the radius of the self-lubricating ball 4 and the working ball 5, so as to form an appropriate contact angle and preload.

[0030] As a further implementation, the radius of the self-lubricating ball 4 is smaller than the radius of the working ball 5, so that the load between the lead screw 1 and the nut 2 is borne by the working ball 5, avoiding the situation where the self-lubricating ball 4 wears too quickly. At the same time, the composite material self-lubricating ball 4 is arranged in a separate row and does not bear the working load, so there is no risk of falling off or breaking quickly. It can rotate smoothly and safely, effectively ensuring the service life of the self-lubricating ball 4.

[0031] As a further implementation, the self-lubricating ball 4 is made of a solid lubricant and a metal alloy matrix, with the solid lubricant uniformly distributed within the metal alloy matrix. Specifically, the solid lubricant is uniformly distributed within the metal matrix, with virtually no difference between the surface and interior of the material. The solid lubricant, uniformly distributed within the metal matrix, is gradually squeezed outwards under pressure and deformation. Initially, the squeezed-out solid lubricant is insufficient, and the resulting lubricating film is inadequate to cover the entire metal surface. As time progresses, more solid lubricant is squeezed out to the surface, and under the repeated action of friction, the solid lubricating film layer is continuously improved, eventually forming a complete and continuous lubricating film.

[0032] As a further implementation, the solid lubricant is made of one or more materials selected from molybdenum disulfide, graphite, soft metals, metal oxides, or rare earth compounds and distributed within a metal alloy matrix. The metal alloy matrix is ​​made of one or more alloys based on iron, copper, nickel, cobalt, or refractory metals. This material possesses excellent high-temperature tribological properties, high-temperature mechanical properties, and high-temperature chemical stability, making it suitable for high-temperature, high-pressure, and high-radiation water environments. Since the working environment is water, the solid lubricant, after detaching from the self-lubricating balls 4, will be evenly distributed in the water without sedimentation.

[0033] Example 2 This embodiment provides a lubrication method for a self-lubricating ball screw structure used in high-temperature water irradiation environments, including: In a high-temperature irradiated water environment, when the ball screw rotates, the self-lubricating balls 4 and the working balls 5 circulate relatively independently each revolution under the action of the reverser 3. When the self-lubricating balls 4 roll in the first and second spiral grooves, the solid lubricant falls off from the metal alloy matrix. Under the action of high-temperature water, the solid lubricant is evenly dispersed in the first and second spiral grooves and diffused to the surface of the first and second spiral grooves. The lubricating film formed plays the role of lubricating the working balls 5.

[0034] While the specific embodiments of the present invention have been described above in conjunction with the accompanying drawings, this is not intended to limit the scope of protection of the present invention. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art without creative effort based on the technical solutions of the present invention are still within the scope of protection of the present invention.

Claims

1. A ball screw self-lubricating structure for irradiating a high-temperature water environment, characterized by, include: The system comprises a lead screw, a nut, self-lubricating balls, working balls, and a reversing device. The lead screw passes through the nut, and multiple turns of self-lubricating balls and working balls are arranged between the nut and the lead screw. The self-lubricating balls and working balls adopt an internal circulation motion. Each turn of the self-lubricating balls and working balls returns to the raceway through the reversing device. Adjacent turns of self-lubricating balls and working balls circulate relatively independently. The self-lubricating balls are located at the end of the nut away from the force-bearing point of the lead screw. The number of working balls is greater than the number of self-lubricating balls. At least one working ball is provided between the self-lubricating ball and the end face of the nut. The self-lubricating ball and the working ball are arranged at intervals or adjacent to each other. The radius of the self-lubricating ball is smaller than the radius of the working ball; The self-lubricating ball bearing is made of a solid lubricant and a metal alloy matrix, wherein the solid lubricant is uniformly distributed in the metal alloy matrix.

2. The self-lubricating ball screw structure for irradiation of a high-temperature water environment according to claim 1, wherein The working ball has at least two rotations, and the self-lubricating ball has at least one rotation.

3. The self-lubricating ball screw structure for irradiation of a high-temperature water environment according to claim 1, wherein The reverser is embedded inside the nut and is fixed by a fixing device. The fixing device is threadedly connected to the nut, and the end of the fixing device is provided with an internal hexagon blind hole.

4. The self-lubricating structure of a ball screw for use in a high-temperature irradiated water environment as described in claim 3, characterized in that, There are multiple reversers, which are evenly distributed along the axial direction of the nut, and the projections of the multiple reversers on the cross-section of the nut are evenly distributed circumferentially.

5. The self-lubricating structure of a ball screw for use in a high-temperature irradiated water environment as described in claim 1, characterized in that, The lead of the first helical groove on the outer side of the lead screw is equal to the lead of the second helical groove on the inner side of the nut.

6. The self-lubricating structure of a ball screw for use in a high-temperature irradiated water environment as described in claim 1, characterized in that, The solid lubricant is made from one or more materials selected from molybdenum disulfide, graphite, soft metals, metal oxides, or rare earth compounds with radiation resistance and distributed in a metal alloy matrix; the metal alloy matrix is ​​made from one or more alloys of iron-based, copper-based, nickel-based, cobalt-based, or refractory metal-based materials.

7. A lubrication method for a self-lubricating ball screw structure used in a high-temperature water irradiation environment as described in any one of claims 1-6, characterized in that, include: In a high-temperature irradiated water environment, when the ball screw rotates, the self-lubricating balls and the working balls circulate relatively independently each revolution under the action of the reverser. When the self-lubricating balls roll in the first and second helical grooves, the solid lubricant falls off from the metal alloy matrix. Under the action of high-temperature water, the solid lubricant is evenly dispersed in the first and second helical grooves and diffuses to the surface of the first and second helical grooves, forming a lubricating film that lubricates the working balls.

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