Ball screw pair

Abstract

The utility model relates to ball screw technology field especially relates to a ball screw pair. Include: screw body, nut cover, a plurality of ball and connecting channel, the first helical groove of axial helix is equipped with in screw body outside wall, the nut cover is covered in screw body outside, its inboard wall is equipped with the second helical groove corresponding with the first helical groove, two halves form helical channel, the ball rolls in the channel, the connecting channel is located between the adjacent first helical groove to connect two, and there is a pair of convex parts extending to the channel oppositely in its slot mouth, the convex part all is equipped with the arc part of adapting with the ball, reduces the deviation when the ball enters and exits the connecting channel through the convex part, avoids the track separation, the arc part provides the smooth transition path to guide the ball, and also limits its lateral swing, prevents the transmission jam and noise, can also disperse the contact stress, reduces the friction wear, finally realizes the stable circulation transmission of ball, promotes the transmission stability and component service life of ball screw pair.

Description

Technical Field

[0001] This utility model relates to the field of ball screw technology, and in particular to a ball screw pair. Background Technology

[0002] A ball screw is a high-precision transmission device that converts rotary motion into linear motion. It is widely used in high-precision electromechanical equipment such as CNC machine tools, industrial robots, and precision positioning systems. Its core working principle is to use the balls to circulate in the helical raceway between the screw and the nut to achieve low-friction and high-efficiency power transmission.

[0003] In traditional ball screw assemblies, a return mechanism is typically installed inside the nut to connect adjacent helical raceways and allow the balls to form a closed loop. However, under high-speed or high-load conditions, the balls are prone to deviation from their trajectory, jamming, or falling off at the return mechanism during the loop, affecting transmission smoothness, accuracy, and lifespan. Therefore, a new ball screw assembly is urgently needed to solve these problems. Utility Model Content

[0004] To overcome the shortcomings of the prior art, this utility model provides a ball screw pair that solves the technical problem that the balls are prone to deviation, jamming, or falling off at the return point during the circulation process of the ball screw pair under high-speed or high-load conditions.

[0005] To achieve the above objectives, this utility model is implemented through the following technical solution: A ball screw assembly, comprising: The lead screw body has a first helical groove on its outer side wall, and the first helical groove is helically arranged along the axial direction of the lead screw body. A nut sleeve is fitted onto the lead screw body. The inner side wall of the nut sleeve is provided with a second spiral groove corresponding to the first spiral groove. The second spiral groove and the first spiral groove are combined to form a spiral channel. A plurality of balls are rotatably disposed within a spiral channel; A connecting channel is provided between an adjacent pair of first spiral grooves. The connecting channel is used to connect the adjacent pair of first spiral grooves. A pair of protrusions are provided at the groove opening of the connecting channel. The pair of protrusions extend into the connecting channel from each other. Each protrusion is provided with an arc-shaped part adapted to the ball. The arc-shaped part is used to guide and constrain the ball.

[0006] Based on the above structure, the principle of the ball screw pair is as follows: When the screw body rotates, the balls roll in the helical channel, driving the nut sleeve to move linearly along the axial direction of the screw body, realizing the mutual conversion between rotational motion and linear motion. The connecting channel is used to connect adjacent first helical grooves, allowing the balls to circulate within the nut sleeve, ensuring that the balls do not leave the helical channel during transmission, thereby achieving continuous transmission. When the balls roll, the protrusion is used to reduce the offset amplitude of the balls when entering or leaving the connecting channel, preventing the balls from deviating from the preset motion trajectory and providing limiting protection for the balls. The shape of the arc-shaped part is adapted to the ball, conforming to the surface of the ball, providing a smooth transition path for the ball, and guiding the ball to enter the next motion trajectory in an orderly manner. Through the adaptive contact with the ball surface, the arc-shaped part can limit the lateral sway of the balls in the connecting channel, ensuring that the balls roll stably in the preset direction, avoiding transmission jamming or noise caused by ball offset. Furthermore, the contact between the arc-shaped part and the balls can disperse contact stress, reduce friction and wear between the balls and the connecting channel, and extend the service life of the components.

[0007] Furthermore, in one ball screw assembly of this application, a pair of limiting portions are provided on the side wall of the nut sleeve. The pair of limiting portions are spaced apart along the axial direction of the nut sleeve, and the limiting portions extend radially into the second helical groove of the nut sleeve. As a preferred embodiment of this application, in one ball screw assembly of this application, the pair of limiting portions are spaced apart along the axial direction of the nut sleeve, which precisely forms a barrier to the balls at both ends of the screw body in the axial direction, limiting the excessive displacement of the balls in the helical channel. When the balls roll in the helical channel, they cannot exceed the axial area between the two limiting portions, thus preventing the screw body from detaching from the nut sleeve.

[0008] Furthermore, in one ball screw assembly of this application, the nut sleeve has a pair of threaded mounting holes corresponding one-to-one with a pair of limiting portions. The limiting portions are screwed into the corresponding threaded mounting holes, and the diameter of the threaded mounting holes is larger than the diameter of the balls. As a preferred embodiment of this application, in one ball screw assembly, the threaded mounting holes serve as the ball filling inlet. During assembly, the operator can directly fill the helical channel with balls through the threaded mounting holes, reducing the difficulty of assembly operations and thus reducing production costs. At the same time, the operator can also inject lubricating medium into the helical channel through the threaded mounting holes.

[0009] Furthermore, in this application, a ball screw assembly includes a screw body comprising a screw and a shaft, the screw and shaft being coaxially arranged sequentially along the axial direction of the screw body, a nut sleeve being sleeved on the screw, and the shaft extending axially beyond the nut sleeve. As a preferred embodiment of this application, in this ball screw assembly, the shaft is used to connect a drive device (not shown) to transmit power to rotate the screw. With the cooperation of the balls, the nut sleeve moves axially. The design of the shaft extending beyond the nut sleeve separates the external connection point from the linear motion area of ​​the nut sleeve, eliminating the need to avoid the movement stroke of the nut sleeve, reducing the spatial layout difficulty during equipment assembly, and making it suitable for compact automated equipment.

[0010] Furthermore, in one ball screw assembly of this application, a sealing plate is provided inside the nut sleeve. The sealing plate is centrally sleeved on the shaft and extends radially to abut against the inner sidewall of the nut sleeve. As a preferred embodiment of this application, the sealing plate in this ball screw assembly serves to prevent dust, moisture, oil, and other impurities from the external environment from entering the transmission working area through the gap between the shaft and the nut sleeve, while also preventing the leakage of lubricating medium within the transmission working area, ensuring that the balls roll in a clean and lubricated environment.

[0011] Furthermore, in one ball screw assembly of this application, the screw has an arc-shaped protrusion on the side near the shaft, and the sealing plate has a corresponding recess on the side near the screw, the recess being used to accommodate the arc-shaped protrusion. As a preferred embodiment of this application, the arc-shaped protrusion and the recess form a "convex-concave interlocking" structure, filling the radial gap between them. The arc-shaped interlocking changes the contact surface from "line contact" to "surface contact," preventing impurities from entering the nut sleeve along the screw axial direction. Furthermore, during assembly, it facilitates fine-tuning of the coaxiality of the screw and shaft after installation, reducing abnormal screw wear caused by assembly errors and improving the service life of the ball screw assembly.

[0012] Furthermore, in one ball screw assembly of this application, the shaft has a mounting hole at the end away from the screw. As a preferred embodiment of this application, the mounting hole serves as a power input interface, enabling a rigid connection with a drive device (not shown), ensuring stable power transmission from external equipment to the shaft, which then drives the screw to rotate.

[0013] As can be seen from the above technical solution, this utility model has the following beneficial effects: The purpose of this invention is to provide a ball screw assembly. By providing a pair of protrusions extending into the channel at the groove opening of the connecting channel, and by providing arc-shaped portions on the protrusions that adapt to the balls, the protrusions reduce the offset of the balls when they enter or leave the connecting channel, preventing the balls from deviating from the preset motion trajectory and providing effective limiting protection for the balls. Simultaneously, the fitting contact between the arc-shaped portions and the ball surface provides a smooth transition path for the balls, guiding them into the next motion trajectory in an orderly manner. Furthermore, the fitting contact between the arc-shaped portions and the balls restricts the lateral sway of the balls within the connecting channel, ensuring stable rolling of the balls in the preset direction and preventing transmission jamming or noise caused by ball offset. In addition, the fitting contact between the arc-shaped portions and the balls also disperses contact stress, reducing friction and wear between the balls and the connecting channel. Ultimately, this achieves stable cyclic transmission of the balls between the helical channel and the connecting channel, improving the transmission stability and component lifespan of the ball screw assembly. Attached Figure Description

[0014] Figure 1 This is a three-dimensional structural schematic diagram of a ball screw pair in an embodiment of this application; Figure 2 This is an exploded view of a ball screw assembly according to an embodiment of this application; Figure 3 This is a cross-sectional view of a ball screw assembly according to an embodiment of this application; Figure 4 This is a three-dimensional structural diagram of the screw body in a ball screw pair according to an embodiment of this application.

[0015] In the figure: 1-lead screw body; 10-first helical groove; 11-lead screw; 110-arc-shaped protrusion; 12-shaft; 120-helical channel; 121-mounting hole; 2-nut sleeve; 20-second helical groove; 21-threaded mounting hole; 3-ball; 4-connecting channel; 41-protrusion; 410-arc-shaped part; 5-limiting part; 6-sealing plate; 60-recess. Detailed Implementation

[0016] like Figure 1 , 2 As shown in Figures 3 and 4, a ball screw assembly includes: The lead screw body 1 has a first spiral groove 10 on its outer side wall, and the first spiral groove 10 is spirally arranged along the axial direction of the lead screw body 1. Nut sleeve 2, the nut sleeve 2 is sleeved on the lead screw body 1, and the inner side wall of the nut sleeve 2 is provided with a second spiral groove 20 corresponding to the first spiral groove 10. The second spiral groove 20 and the first spiral groove 10 are combined to form a spiral channel 120. A plurality of ball bearings 3 are rotatably disposed within the spiral channel 120; A connecting channel 4 is provided between an adjacent pair of first spiral grooves 10. The connecting channel 4 is used to connect the adjacent pair of first spiral grooves 10. A pair of protrusions 41 are provided at the groove opening of the connecting channel 4. The pair of protrusions 41 extend into the connecting channel 4 relative to each other. Each protrusion 41 is provided with an arc-shaped part 410 adapted to the ball 3. The arc-shaped part 410 is used to guide and constrain the ball 3.

[0017] Based on the above structure, the principle of the ball screw pair is as follows: When the screw body 1 rotates, the ball 3 rolls within the helical channel 120, driving the nut sleeve 2 to move linearly along the axial direction of the screw body 1, realizing the mutual conversion between rotational motion and linear motion. The connecting channel 4 is used to connect adjacent first helical grooves 10, allowing the ball 3 to circulate within the nut sleeve 2, ensuring that the ball 3 does not detach from the helical channel 120 during transmission, thereby achieving continuous transmission. When the ball 3 rolls, the protrusion 41 is used to reduce the offset amplitude of the ball 3 when entering or leaving the connecting channel 4, preventing the ball 3 from detaching from the preset position. The movement trajectory provides limiting protection for the ball 3. The shape of the arc-shaped part 410 is adapted to the ball 3, which can fit the surface of the ball 3 and provide a smooth transition path for the ball 3, guiding the ball 3 to enter the next movement trajectory in an orderly manner. Through the adaptive contact with the surface of the ball 3, the arc-shaped part 410 can limit the lateral sway of the ball 3 in the connecting channel 4, ensuring that the ball 3 rolls stably in the preset direction, avoiding transmission jamming or noise caused by the deviation of the ball 3. In addition, the contact between the arc-shaped part 410 and the ball 3 can disperse the contact stress, reduce the friction and wear between the ball 3 and the connecting channel 4, and extend the service life of the component.

[0018] In this embodiment, a pair of limiting portions 5 are provided on the side wall of the nut sleeve 2. The pair of limiting portions 5 are spaced apart along the axial direction of the nut sleeve 2, and extend radially into the second helical groove 20. The pair of limiting portions 5 spaced apart along the axial direction of the nut sleeve 2 precisely forms a barrier against the balls 3 at both ends of the lead screw body 1, limiting the excessive displacement of the balls 3 within the helical channel 120. When the balls 3 roll within the helical channel 120, they cannot exceed the axial area between the two limiting portions 5, thus preventing the lead screw body 1 from detaching from the nut sleeve 2. The limiting portions 5 can be screws, which are screwed onto the nut sleeve 2.

[0019] In this embodiment, the nut sleeve 2 is provided with a pair of threaded mounting holes 21 corresponding to a pair of limiting parts 5. The limiting parts 5 are screwed onto the corresponding threaded mounting holes 21, and the diameter of the threaded mounting holes 21 is larger than the diameter of the ball 3. The threaded mounting holes 21 are used as the filling inlet for the ball 3. During assembly, the operator can directly fill the ball 3 into the spiral channel 120 through the threaded mounting holes 21, reducing the difficulty of assembly operations and thus reducing production costs. At the same time, the operator can also inject lubricating medium into the spiral channel 120 through the threaded mounting holes 21.

[0020] In this embodiment, the lead screw body 1 includes a lead screw 11 and a shaft 12. The lead screw 11 and shaft 12 are coaxially arranged sequentially along the axial direction of the lead screw body 1. The nut sleeve 2 is sleeved and installed on the lead screw 11, and the shaft 12 extends axially out of the nut sleeve 2. The shaft 12 is used to connect a drive device (not shown) to transmit power and drive the lead screw 11 to rotate. With the cooperation of the ball bearings 3, the nut sleeve 2 moves axially. The design of the shaft 12 extending out of the nut sleeve 2 separates the external connection point from the linear motion area of ​​the nut sleeve 2, eliminating the need to avoid the movement stroke of the nut sleeve 2, reducing the spatial layout difficulty during equipment assembly, and making it suitable for compact automated equipment. The lead screw 11 and shaft 12 are integrally formed structures.

[0021] In this embodiment, the nut sleeve 2 is provided with a sealing plate 6, which is centrally fitted onto the shaft 12 and extends radially to abut against the inner sidewall of the nut sleeve 2. The sealing plate 6 serves to prevent dust, moisture, oil, and other impurities from the external environment from entering the transmission working area through the gap between the shaft 12 and the nut sleeve 2, while also preventing the leakage of lubricating medium from the transmission working area, ensuring that the balls 3 roll in a clean and lubricated environment. The sealing plate 6 can be made of soft rubber.

[0022] In this embodiment, the lead screw 11 has an arc-shaped protrusion 110 on the side near the shaft 12, and the sealing plate 6 has a corresponding recess 60 on the side near the lead screw 11. The recess 60 is used to accommodate the arc-shaped protrusion 110. The arc-shaped protrusion 110 and the recess 60 form a "concave-convex fitting" structure, which fills the radial gap between them. The arc-shaped fitting changes the contact surface between the two from "line contact" to "surface contact", preventing impurities from entering the interior of the nut sleeve 2 along the axial direction of the lead screw 11. Furthermore, during assembly, it is convenient to fine-tune the coaxiality of the lead screw 11 and the shaft 12 after the shaft 12 is installed, reducing abnormal wear of the lead screw 11 caused by assembly errors and improving the service life of the ball screw pair.

[0023] In this embodiment, the end of the shaft 12 furthest from the lead screw 11 is provided with a mounting hole 121. The mounting hole 121 serves as a power input interface, allowing for a rigid connection with a drive device (not shown), ensuring stable power transmission from an external device to the shaft 12, which then drives the lead screw 11 to rotate. The mounting hole 121 is a spline hole, connecting to the spline drive shaft of the drive device (not shown). In other embodiments, the mounting hole 121 may be a threaded hole, threadedly connecting to the drive shaft of the drive device.

[0024] The technical principles of this utility model have been described above with reference to specific embodiments. These descriptions are merely for explaining the principles of this utility model and should not be construed as limiting the scope of protection of this utility model in any way. Based on the explanation herein, those skilled in the art can conceive of other specific embodiments of this utility model without creative effort, and these embodiments will all fall within the scope of protection of this utility model.

Claims

1. A ball screw assembly, characterized in that: include: The lead screw body (1) has a first spiral groove (10) on its outer side wall, and the first spiral groove (10) is spirally arranged along the axial direction of the lead screw body (1). Nut sleeve (2), the nut sleeve (2) is sleeved on the lead screw body (1), and the inner side wall of the nut sleeve (2) is provided with a second spiral groove (20) corresponding to the first spiral groove (10). The second spiral groove (20) and the first spiral groove (10) are joined together to form a spiral channel (120). A plurality of balls (3) are rolled within the spiral channel (120); A connecting channel (4) is provided between an adjacent pair of first spiral grooves (10). The connecting channel (4) is used to connect an adjacent pair of first spiral grooves (10). A pair of protrusions (41) are provided at the groove opening of the connecting channel (4). The pair of protrusions (41) extend into the connecting channel (4) respectively. Each of the protrusions (41) is provided with an arc-shaped part (410) adapted to the ball (3). The arc-shaped part (410) is used to guide and constrain the ball (3).

2. The ball screw assembly according to claim 1, characterized in that: The nut sleeve (2) has a pair of limiting parts (5) on its side wall. The pair of limiting parts (5) are spaced apart along the axial direction of the nut sleeve (2). The limiting parts (5) extend radially into the second spiral groove (20) of the nut sleeve (2).

3. A ball screw assembly according to claim 2, characterized in that: The nut sleeve (2) is provided with a pair of threaded mounting holes (21) corresponding to a pair of limiting parts (5). The limiting parts (5) are screwed onto the corresponding threaded mounting holes (21). The diameter of the threaded mounting holes (21) is larger than the diameter of the ball (3).

4. A ball screw assembly according to claim 1, characterized in that: The lead screw body (1) includes: lead screw (11) and shaft (12). The lead screw (11) and shaft (12) are coaxially arranged in sequence along the axial direction of the lead screw body (1). The nut sleeve (2) is sleeved and installed on the lead screw (11). The shaft (12) extends axially out of the nut sleeve (2).

5. A ball screw assembly according to claim 4, characterized in that: The nut sleeve (2) is provided with a sealing plate (6), which is centrally sleeved on the shaft (12) and extends radially to abut against the inner sidewall of the nut sleeve (2).

6. A ball screw assembly according to claim 5, characterized in that: The lead screw (11) has an arc-shaped protrusion (110) on the side near the shaft (12), and the sealing plate (6) has a concave part (60) on the side near the lead screw (11) that corresponds to the arc-shaped protrusion (110). The concave part (60) is used to accommodate the arc-shaped protrusion (110).

7. A ball screw assembly according to claim 4, characterized in that: The shaft (12) has a mounting hole (121) at the end away from the lead screw (11).

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