External circulation ball screw drive device

Abstract

This utility model discloses an external circulation ball screw transmission device, including a nut, a screw that mates with the nut, balls, and a reversing assembly. Both the inner and outer peripheral walls of the nut and the screw have raceways. When the screw mates with the nut, the two raceways combine to form a rolling path for the balls. The reversing assembly consists of two halves of a reversing device. The inner wall of each reversing device has a reversing groove. When the two reversing devices are closed, the two reversing grooves combine to form a reversing path, which communicates with the ball path. The outer peripheral wall of the nut has a mounting groove for accommodating the two halves of the reversing device. The nut has a limiting structure for closing the two halves of the reversing device and combining the two reversing grooves into a reversing path, as well as a limiting structure for radially limiting and axially fixing the two halves of the reversing device. It also has a mounting structure that works in conjunction with the limiting structure to fix the limiting structure to the nut. This utility model solves the problems of inconvenient assembly and insufficient positioning stability of the integrated reversing device in traditional external circulation ball screws.

Description

Technical Field

[0001] This utility model relates to the field of ball screw technology, specifically to an external circulation ball screw transmission device. Background Technology

[0002] As a precision transmission component, ball screws are widely used in various mechanical transmission fields such as machine tools, automated equipment, and precision instruments due to their advantages of high transmission efficiency, smooth movement, and high positioning accuracy. External circulation ball screws rely on a return assembly to achieve the circulation of the balls, so the structure, assembly performance, and positioning reliability of the return assembly directly affect the overall operating performance and service life of the ball screw.

[0003] Currently, most mainstream external circulation ball screws on the market adopt an integrated return device. This type of structure has obvious defects in actual production and assembly: the integrated return device has a fixed overall volume, making alignment and installation difficult when assembling with the nut, resulting in low assembly efficiency; at the same time, the integrated return device relies on a single fixed structure for limiting, and after being subjected to axial and radial loads for a long time, it is prone to loosening and displacement, resulting in poor positioning stability. This not only aggravates the wear of the balls but also reduces the transmission accuracy and load-bearing capacity of the ball screw, making it difficult to meet the requirements of high-precision and high-load working conditions. Utility Model Content

[0004] To address the shortcomings of existing technologies, this utility model provides an external circulation ball screw transmission device, which solves the problems of inconvenient assembly and insufficient positioning stability of the integrated reversing device in traditional external circulation ball screws.

[0005] To achieve the above objectives, this utility model provides an external circulation ball screw transmission device, including a nut, a screw that mates with the nut, balls, and a reversing assembly. Both the inner and outer peripheral walls of the nut and the screw have raceways. When the screw mates with the nut, the two raceways combine to form a rolling path for the balls. The reversing assembly comprises two halves of a reversing device. The inner wall of each reversing device has a reversing groove. When the two reversing devices are closed, the two reversing grooves combine to form a reversing path. The reversing path communicates with the ball path. The outer peripheral wall of the nut has a mounting groove for accommodating the two halves of the reversing device. The nut is provided with a limiting structure for closing the two halves of the reversing device and combining the two reversing grooves into a reversing path, and for radially limiting and axially fixing the two halves of the reversing device. An mounting structure is also provided to engage with the limiting structure to fix the limiting structure to the nut.

[0006] The advantages of adopting the above technical solution are as follows: The technology uses a split two-half reverser to form a reversing assembly, which creates a complete reversing path when the two halves of the reverser are closed, thus adapting to the needs of ball screw circulation. The split structure also reduces the difficulty of component processing and on-site assembly, thereby improving assembly convenience. The outer peripheral wall of the nut is provided with a dedicated mounting groove to accommodate the two halves of the reverser, allowing the reversing assembly to be embedded, resulting in a more compact overall structure. The matching limiting structure can simultaneously achieve radial limiting and axial fixing of the two halves of the reverser, thereby constraining the positional deviation of the reverser during operation and improving the overall positioning stability. Furthermore, the linkage between the mounting structure and the limiting structure further strengthens the reliability of the connection between each component, ensuring the long-term stable operation of the reversing assembly. This effectively improves the defects of traditional integrated reversing devices, such as cumbersome assembly and easy positioning failure, and enhances the overall transmission reliability and smooth operation of the ball screw.

[0007] The present invention further comprises: the limiting structure including a pressure plate, the bottom wall of the pressure plate having a through groove, the radial cross-section of the through groove being arc-shaped, the radial cross-section of the mounting groove being arc-shaped, the pressure plate being pressed onto the nut and fixedly connected to the nut through the mounting structure, when the pressure plate is pressed onto the nut, the through groove and the mounting groove combine to form a mounting hole for accommodating two reversers, and the partial outer peripheral walls of the two reversers are respectively abutting and fitting with the inner peripheral walls of the mounting holes.

[0008] The advantages of adopting the above technical solution are as follows: The limiting structure in the above technology adopts a pressure plate structure, and the arc-shaped through groove at the bottom of the pressure plate cooperates with the arc-shaped mounting groove on the nut to form a mounting hole for accommodating the two halves of the reverser. This allows the arc-shaped fitting structure to fully wrap around the outer periphery of the reverser, thereby strengthening the radial constraint effect on the reverser and preventing radial movement of the reverser. The pressure plate is directly pressed against the surface of the nut, and the overall pressing structure is used to achieve the overall convergence and positioning of the two halves of the reverser, ensuring that the two halves of the reverser are accurately closed and keeping the return path intact and unobstructed. The pressure plate is firmly connected to the nut by the mounting structure, so that the pressure plate, the reverser and the nut form a tightly fitted overall structure, thereby improving the fitting degree between components, further optimizing the positioning effect, and ensuring smooth circulation of the ball between the return path and the rolling path.

[0009] The present invention further comprises: the mounting structure including two set bolts arranged opposite each other; set holes are provided at both ends of the pressure plate; mating holes are provided on the outer peripheral wall of the nut at positions corresponding to the two set holes; the two set bolts correspond one-to-one with the two set holes and are inserted into each other; each set bolt is threadedly connected to its corresponding mating hole; and the bottom wall of the nut end of the set bolt abuts against the top wall of the pressure plate.

[0010] The advantages of adopting the above technical solution are as follows: The installation structure in the above technology uses two sets of relatively arranged set bolts. The set bolts pass through the set bolt holes of the pressure plate and are threadedly connected to the nut mating holes. The pressure plate and the nut are firmly locked by the threaded connection. The overall threaded connection is easy to disassemble and assemble, and facilitates later maintenance and parts replacement. The set bolt nuts press against the surface of the pressure plate, forming a downward pressure limit on the pressure plate to prevent the pressure plate from tilting or shifting, and to continuously ensure the pressing effect of the pressure plate on the two halves of the reversing device. The two sets of symmetrically arranged set bolts can achieve uniform force distribution and avoid uneven force on one side of the pressure plate, thereby ensuring that the pressing force is balanced at all parts of the pressure plate, stably maintaining the combined shape of the two halves of the reversing device, and thus improving the assembly firmness and operational stability of the entire reversing assembly.

[0011] The present invention further includes: a limiting groove is provided on the outer peripheral wall of the nut for partial accommodation of the pressure plate, the width of the limiting groove is adapted to the width of the pressure plate, and the two side walls of the pressure plate are respectively in contact with the inner side walls of the limiting groove.

[0012] The advantages of adopting the above technical solution are as follows: In the above technology, a limiting groove adapted to the size of the pressure plate is opened on the outer peripheral wall of the nut, allowing the pressure plate to be embedded inside the limiting groove. The inner walls on both sides of the limiting groove form a lateral obstruction to the pressure plate, restricting lateral displacement of the pressure plate and achieving lateral positioning of the pressure plate. Furthermore, the matching setting of the limiting groove and the pressure plate allows for pre-positioning of the pressure plate, enabling rapid alignment during assembly and simplifying the assembly process. The pressure plate is entirely embedded in the limiting groove, reducing the outward protrusion of the component, further optimizing the overall compactness of the device, while also reducing the probability of the pressure plate being subjected to external collisions or scratches, protecting the structural form of the pressure plate, continuously ensuring the pressure plate's pressing and positioning function on the two halves of the reversing device, and extending the service life of the component.

[0013] The present invention further includes the following feature: the reverser is formed by powder metallurgy or by stamping.

[0014] The advantages of adopting the above technical solution are as follows: The reverser in the above technology is processed by powder metallurgy forming process or stamping forming process. The two forming processes are suitable for different production scenarios and batch production needs. Among them, the powder metallurgy process can ensure that the overall structure of the reverser is dense and the forming accuracy is high, ensuring that the profile of the return groove is regular and conducive to the smooth passage of the ball. The stamping forming process is simple and efficient, which can effectively reduce the processing cost of parts and is suitable for large-scale mass production. Both forming processes can ensure the structural strength and dimensional consistency of the split reverser, so that multiple reversers can be accurately assembled to form a standard return path after assembly, ensuring the uniformity of performance of different products, while simplifying the processing flow of parts and improving the overall production economy. Attached Figure Description

[0015] Figure 1 This is a front view of the present utility model; Figure 2 This is a cross-sectional view of the present invention; Figure 3 This is a three-dimensional view of the two inverters combined in this utility model; Figure 4 This is a three-dimensional view of a single inverter in this utility model. Detailed Implementation

[0016] This utility model provides an external circulation ball bearing 21 lead screw 2 transmission device, including a nut 1, a lead screw 2 that cooperates with the nut 1, balls 21, and a reversing assembly. Both the inner circumferential wall of the nut 1 and the outer circumferential wall of the lead screw 2 are provided with raceways 11. When the lead screw 2 cooperates with the nut 1, the two raceways 11 combine to form a rolling path 12 for the balls 21 to move. The reversing assembly includes two halves of a reversing device 3. The inner wall of each reversing device 3 is provided with a reversing groove 31. When the two reversing devices 3 are closed, the two reversing grooves 31 combine to form a reversing path 32. The passage 32 is connected to the ball bearing 21 passage. The outer peripheral wall of the nut 1 has a mounting groove 13 for accommodating the two halves of the reversing device 3. The nut 1 is provided with a limiting structure for closing the two halves of the reversing device 3 and combining the two reversing grooves 31 into a reversing passage 32, and for radially limiting and axially fixing the two halves of the reversing device 3. An mounting structure is also provided to engage with the limiting structure to fix the limiting structure to the nut 1. The limiting structure includes a pressure plate 4, the bottom wall of which has a through groove 41. The radial cross-section of the through groove 41 is arc-shaped. The mounting groove 13 has an arc-shaped radial cross-section. The pressure plate 4 is pressed onto the nut 1 and fixedly connected to the nut 1 through the mounting structure. When the pressure plate 4 is pressed onto the nut 1, the through groove 41 and the mounting groove 13 combine to form a mounting hole for accommodating two reversers 3. The outer peripheral walls of the two reversers 3 are partially abutted against the inner peripheral walls of the mounting holes. The mounting structure includes two oppositely arranged set bolts 42. Set holes 43 are provided at both ends of the pressure plate 4. Matching holes 14 are provided on the outer peripheral wall of the nut 1 at positions corresponding to the two set holes 43. The two set bolts 42 correspond one-to-one with the two set holes 43 and are inserted into each other. Each set bolt 42 is threadedly connected to its corresponding mating hole 14. The bottom wall of the nut end of the set bolt 42 abuts against the top wall of the pressure plate 4. The outer peripheral wall of the nut 1 is provided with a limiting groove 15 for partial accommodation of the pressure plate 4. The width of the limiting groove 15 is adapted to the width of the pressure plate 4, and the two side walls of the pressure plate 4 respectively contact the inner side walls of the limiting groove 15. The reverser 3 is formed by powder metallurgy or stamping.

[0017] Detailed installation procedure for this device: First, clean the burrs and impurities from the surfaces of components such as the lead screw, nut, two halves of the reversing device, pressure plate, set bolt, and balls. Then, align and join the two reversing devices to form a complete reversing path by splicing the internal reversing grooves. Next, place the assembled reversing device into the mounting groove on the outer circumference of the nut. Embed the pressure plate into the limiting groove of the nut, so that the bottom through groove of the pressure plate matches the mounting groove to cover the reversing device. Then, pass the set bolt through the set hole of the pressure plate and thread it into the nut's mating hole. Next, fill the raceway between the lead screw and the nut with balls, ensuring that the balls connect the rolling path and the reversing path. Finally, smoothly screw the nut onto the lead screw. Manually rotate the nut back and forth to check the connection status of each component and the operation of the balls. Once it is confirmed that there is no looseness or jamming, the installation is complete.

[0018] The reversing device described above operates on the same principle as the existing external circulation ball screw reversing device. This solution uses two half-reversing devices to form an integral structure. After the two are spliced ​​together, a complete reversing path is formed inside. The screw and nut cooperate to form a ball rolling path. The ball rolls in the rolling path with the relative movement of the nut and the screw. When the ball runs to the end position, it will enter the reversing path of the reversing device to complete the reversing and return flow, thereby realizing the circulation of the ball. The overall working logic and ball reversing method follow the existing mature principle, so they will not be described in detail.

[0019] The foregoing has shown and described the basic principles and main features of this utility model, as well as its advantages. Those skilled in the art should understand that this utility model is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of this utility model. Various changes and modifications may be made to this utility model without departing from its spirit and scope. All such changes and modifications fall within the scope of protection of this utility model as defined by the appended claims and their equivalents.

Claims

1. An outer loop ball screw drive device, comprising a nut, a screw rod matched with the nut, balls and a return assembly, a raceway is formed on the inner circumferential wall of the nut and the outer circumferential wall of the screw rod, the two raceways combine to form a rolling passage for the balls when the screw rod is matched with the nut, characterized in that: The reversing assembly comprises two reversing halves, each with a reversing groove on its inner wall. When the two reversing halves are closed, the two reversing grooves combine to form a reversing passage, which is connected to the ball bearing passage. The outer peripheral wall of the nut has a mounting groove for accommodating the two reversing halves. The nut is provided with a limiting structure for closing the two reversing halves and combining the two reversing grooves to form a reversing passage, and for radially limiting and axially fixing the two reversing halves. It also has a mounting structure for engaging with the limiting structure to fix the limiting structure to the nut.

2. The external circulation ball screw transmission device according to claim 1, characterized in that: The limiting structure includes a pressure plate, the bottom wall of which has a through groove with an arc-shaped radial cross-section. The mounting groove also has an arc-shaped radial cross-section. The pressure plate is pressed onto a nut and is fixedly connected to the nut via a mounting structure. When the pressure plate is pressed onto the nut, the through groove and the mounting groove combine to form a mounting hole for accommodating two inverters. The outer peripheral walls of the two inverters abut against the inner peripheral walls of the mounting holes.

3. The external circulation ball screw transmission device according to claim 2, characterized in that: The mounting structure includes two set bolts arranged opposite each other. Set bolts are provided at both ends of the pressure plate. Matching holes are provided on the outer peripheral wall of the nut at the positions corresponding to the two set bolts. The two set bolts correspond one-to-one with the two set bolts and are inserted into each other. Each set bolt is threadedly connected to its corresponding matching hole. The bottom wall of the nut end of the set bolt abuts against the top wall of the pressure plate.

4. The external circulation ball screw transmission device according to claim 2, characterized in that: The outer peripheral wall of the nut is provided with a limiting groove for partial accommodation of the pressure plate. The width of the limiting groove is adapted to the width of the pressure plate, and the two side walls of the pressure plate are respectively in contact with the inner side walls of the limiting groove.

5. The external circulation ball screw transmission device according to claim 1, characterized in that: The inverter is formed by powder metallurgy or stamping.

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