Phase-adjustable plug-in ball screw pair

Abstract

The application discloses a phase-adjustable plug-in plate type ball screw pair and belongs to the technical field of ball screw transmission, comprising a ball screw, a ball nut, a plug-in plate type steel ball reversing device, a sleeve and an adjusting screw, the ball nut is provided with a stepped radial groove penetrating a ball channel, the reversing device is assembled in the groove, two groups of fine tooth adjusting screws are respectively abutted against axial two ends of the reversing device and are used for adjusting the axial phase, the radial groove and the reversing device are provided with an axial movement gap of 1+ / -0.02 mm, a cam sine curve is arranged at the center of the ball return channel, and the polar coordinate equation can be adapted to different specifications of steel balls through a lift parameter, the scheme can compensate for axial position deviation caused by processing deformation, realizes high-precision centering of the ball return channel and the ball channel, eliminates steel ball reversing impact through continuous and smooth ball return curves, realizes long-period maintenance-free through a composite lubrication and sealing structure, the overall structure is compact, and the ball screw pair is suitable for various precise and compact linear transmission scenes.

Description

Technical Field

[0001] This application relates to the field of ball screw transmission technology, and provides a phase-adjustable insert-type ball screw pair. Background Technology

[0002] As a key component in the transmission systems of precision machinery such as CNC machine tools, the smoothness of ball screw operation, noise level, and ease of maintenance directly affect the overall performance and service life of the equipment. With the increasing demands of the manufacturing industry for high precision, high efficiency, and long-term maintenance-free operation, higher requirements are being placed on the structural design and functional integration of ball screw assemblies.

[0003] Currently, in common ball screw assembly structures, the outer circumference of the ball nut is typically machined with multiple reverse holes for installing a ball reversing device. The steel balls circulate between the threaded ball track inside the nut and the return ball channel of the reversing device, achieving rolling transmission. The reversing device is generally fixedly installed, and the alignment of its return ball channel with the nut's ball track depends on machining precision. Furthermore, to reduce friction and wear, some designs incorporate sealing or lubricating elements at both ends of the nut. These elements store grease, extending maintenance intervals and preventing external contaminants from entering the ball track area.

[0004] However, the existing structure has two prominent problems in practical applications. First, the positional accuracy between the nut ball track and the reverse groove is difficult to control stably. Because the nut ball track is a complex three-dimensional spatial structure, its alignment with the reverse groove is affected by multiple factors such as axial, circumferential and radial directions. In addition, process deviations such as heat treatment deformation make it difficult to achieve the ideal level of alignment accuracy between the two. This leads to the steel ball impacting or getting stuck in the transition area, which seriously affects the smooth operation of the lead screw pair. Summary of the Invention

[0005] This application addresses the problem of impact or jamming of steel balls in the transition region of existing ball screw assemblies by providing a phase-adjustable insert-plate type ball screw assembly, comprising: Ball screw; A ball nut is sleeved on the outside of the ball screw. The inner circumferential surface of the ball nut is provided with a ball track, and the radial direction of the ball nut is provided with a radial groove that extends to the ball track. A plate-type steel ball reversing device is installed in the radial groove. The inside of the plate-type steel ball reversing device is provided with a ball return channel. The inlet and outlet of the ball return channel are connected to the ball track. A sleeve is fitted over the outside of the insert-type steel ball reversing device and the ball nut; An adjusting screw is mounted on the ball nut, and the end of the adjusting screw abuts against the insert-type steel ball reversing device, for adjusting the axial position of the insert-type steel ball reversing device in the radial groove.

[0006] In one feasible implementation, the center curve of the return ball channel is a cam-like sine curve, and its polar coordinate equation is as follows: ; In the formula, r is the radius of the polar coordinates of the bead return curve equation. denoted as polar coordinate angular displacement, and h is the distance the steel ball travels to its highest point.

[0007] In one feasible implementation, the radial groove is a stepped radial groove; The insert-type steel ball reversing device is embedded in the stepped radial groove, and a gap is left between the insert-type steel ball reversing device and the axial side walls of the stepped radial groove.

[0008] In one feasible implementation, the adjusting screws are configured as two sets; The two sets of adjusting screws are respectively installed on the two side walls of the stepped radial groove along the axial direction, and the ends of the two sets of adjusting screws respectively abut against the two end faces of the insert-type steel ball reversing device along the axial direction.

[0009] In one feasible implementation, the adjusting screws have a fine-tooth structure, and the coaxiality of the ball return channel and the ball track is adjusted by adjusting two sets of the adjusting screws.

[0010] In one feasible implementation, the insert-type steel ball reversing device has 3 to 6 ball return channels.

[0011] In one feasible implementation, a lubrication and sealing unit is also included, wherein mounting holes are provided on both axial end faces of the ball nut, and the lubrication and sealing unit is installed in the mounting holes; The lubrication and sealing unit includes a lubricating element located near the inside of the ball nut and a sealing element located on the outside.

[0012] In one feasible implementation, the lubricant is made of polyurethane foam material; The lubricating component has pores inside, which are filled with grease, and a V-shaped cavity is formed on the lubricating component. The volume V of the V-shaped cavity satisfies the following formula: ; In the formula, Where is the diameter of the steel ball in mm, L is the life of the ball screw assembly in years, and k is a calculation coefficient.

[0013] In one feasible implementation, the seal is a spiral polytetrafluoroethylene (PTFE) sealing sheet, which is fixed to the outer end face of the lubricant.

[0014] In one feasible implementation, the axial clearance between the insert-type steel ball reversing device and the stepped radial groove is 1 ± 0.02 mm.

[0015] The phase-adjustable insert-type ball screw assembly provided in this application utilizes a stepped radial groove paired with double-sided fine-pitch adjusting screws to achieve axial phase adjustment of the insert-type ball reversing device. This compensates for axial misalignment caused by machining deviations in the ball nut's raceway and radial groove, as well as deformation from heat treatment. It eliminates the need for rework of the nut body, reducing machining accuracy requirements, improving product yield, and controlling production costs. The fine-pitch thread enables micron-level coaxiality adjustment, and the double-sided locking structure maintains a smooth connection between the return ball channel and the raceway over the long term, preventing operational vibration from causing the reversing device to shift. The return ball channel adopts a cam-like sine curve center trajectory with continuous curvature throughout, ensuring smooth changes in radial velocity and acceleration during ball reversal. This eliminates instantaneous impact loads, reduces wear between the ball and the channel's inner wall, and lowers operational vibration and noise. The curve can be adapted to different diameter ball diameters by adjusting the lift parameters, facilitating rapid design for serialized products. The overall insert-type structure occupies less axial space, adapting to compact installation conditions. The sleeve can seal the radial groove, ensuring stable radial constraint of the reversing device. Attached Figure Description

[0016] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with the implementation of this application and, together with the description, serve to explain the principles of the embodiments of this application. It is obvious that the drawings described below are merely some embodiments of the implementation of this application, and those skilled in the art can obtain other drawings based on these drawings without any inventive effort.

[0017] Figure 1 A schematic diagram of a phase-adjustable insert-type ball screw pair structure is shown for an exemplary embodiment of this application; Figure 2 This is a schematic diagram of the structure of a plate-type steel ball reversing device shown in an exemplary embodiment of this application; Figure 3 This is a three-dimensional structural schematic diagram of a ball nut shown as an exemplary embodiment of this application; Figure 4 This is a schematic cross-sectional view of a ball nut as shown in an exemplary embodiment of this application; Figure 5 This is a three-dimensional structural schematic diagram of a lubrication and sealing unit shown in an exemplary embodiment of this application; Figure 6 This is a schematic cross-sectional view of a lubrication and sealing unit as shown in an exemplary embodiment of this application.

[0018] Attached image captions: 1-Ball screw; 2-Ball nut; 3-Insertion plate type steel ball reversing device; 4-Steel ball; 5-Sleeve; 6-Adjusting screw; 7-Lubrication and sealing unit; 21-Ball track; 22-Radial groove; 31-Return ball channel; 71-Lubricating component; 72-Sealing component; 73-V-shaped cavity. Detailed Implementation

[0019] Exemplary embodiments will now be described more fully with reference to the accompanying drawings. However, these exemplary embodiments can be implemented in many forms and should not be construed as limited to the examples set forth herein; rather, these embodiments are provided to make the embodiments of this application more comprehensive and complete, and to fully convey the concept of the exemplary embodiments to those skilled in the art. The described features, structures, or characteristics can be combined in any suitable manner in one or more embodiments. In the following description, numerous specific details are provided to give a thorough understanding of the implementation of embodiments of this application.

[0020] In the manufacturing and actual operation of ball screw assemblies, the alignment accuracy between the ball track inside the ball nut and the return ball channel of the reversing device is one of the core factors affecting the smoothness of the ball circulation. Due to the three-dimensional spatial structure of the helical ball track inside the ball nut, multiple parameters such as the axial position of the track, the helical starting angle, and the pitch accuracy all affect its positional correspondence with the mounting structure of the reversing device. Furthermore, clamping errors during manufacturing and deformation during heat treatment can further amplify positional deviations. Positional deviations can cause the ball to form a stepped structure at the junction of the track and the return ball channel. When the ball passes through, it generates a hard impact, exacerbating wear between the ball and the inner wall of the channel, causing vibration and noise. In severe cases, the ball may even become stuck, leading to the failure of the ball screw drive.

[0021] Based on the above issues, referring to Figures 1-4 As shown, this embodiment provides a phase-adjustable insert-plate type ball screw pair. Through an axially movable reversing device structure, it compensates for positional deviations caused by machining, improving the smoothness of the steel ball 4 circulation and the reliability of transmission. The phase-adjustable insert-plate type ball screw pair of this embodiment includes a ball screw 1, which is a long-shaft component with a continuous helical raceway machined on its outer circumference. The cross-section of the helical raceway is arc-shaped, adapting to the outer contour surface of the steel ball 4. The ball screw 1 serves as a transmission reference component, capable of rotating around its own axis or moving linearly along its own axis, thus realizing the mutual conversion between rotational and linear motion and transmitting power and motion.

[0022] Furthermore, the ball nut 2 is sleeved on the outside of the ball screw 1. The ball nut 2 is a hollow cylindrical sleeve structure, with the diameter of its hollow inner cavity being larger than the outer diameter of the ball screw 1, forming an annular receiving space between them for placing the steel balls 4 and installing related functional components. A ball track 21 is formed on the inner circumferential surface of the ball nut 2. The ball track 21 is a groove structure that extends spirally along the inner circumferential surface of the ball nut 2. The spiral parameters of the ball track 21 are consistent with the spiral raceway parameters on the outer circumference of the ball screw 1. The two are arranged opposite each other to form a rolling channel for the steel balls 4. The steel balls 4 are filled in this rolling channel. When the ball screw 1 and the ball nut 2 rotate relative to each other, the steel balls 4 roll along the rolling channel, converting the sliding friction between them into rolling friction, thereby reducing frictional resistance during transmission and improving transmission efficiency.

[0023] The ball nut 2 has a radial groove 22 extending through to the ball track 21. The radial groove 22 extends from the outer peripheral surface of the ball nut 2 towards the inner peripheral surface until it completely penetrates the ball track 21 area on the inner peripheral surface, connecting the external space of the ball nut 2 with the internal space of the ball track 21 through the radial groove 22. The radial groove 22 provides space for the installation and accommodation of the insert-type ball reversing device 3, and also provides guidance for the axial movement of the insert-type ball reversing device 3. In one embodiment, the radial groove 22 is located at the middle position of the axial direction of the ball nut 2, and its axial extension direction is consistent with the axial direction of the ball nut 2. The circumferential width of the radial groove 22 is adapted to the circumferential width of the insert-type ball reversing device 3, so that after the insert-type ball reversing device 3 is installed, the circumferential direction is limited, and it can only move in the axial direction.

[0024] In another embodiment, the radial groove 22 can be located off-axially at the ball nut 2, and can be adjusted according to the actual circuit layout requirements, as long as the return ball channel 31 can be connected to the ball track 21. The radial outer surface of the insert-type steel ball reversing device 3 can be provided with a disassembly groove, which makes it easy to use tools to pull it out of the radial groove 22 for easy disassembly and maintenance.

[0025] The insert-plate type steel ball reversing device 3 is installed inside the radial groove 22. The insert-plate type steel ball reversing device 3 is an integral plate-shaped structural component, its outer contour corresponding to and matching the inner contour of the radial groove 22, allowing it to slide axially along the guide of the radial groove 22. The insert-plate type steel ball reversing device 3 has a return ball channel 31 inside, which is an arc-shaped channel penetrating the interior of the insert-plate type steel ball reversing device 3. The inlet and outlet of the return ball channel 31 are both located on the radially inner surface of the insert-plate type steel ball reversing device 3, and both the inlet and outlet are connected to the ball track 21 on the inner circumferential surface of the ball nut 2. When the steel ball 4 rolls along the ball track 21 to the inlet position, it can enter the interior of the return ball channel 31 from the inlet, move along the arc-shaped path of the return ball channel 31, and finally return to the ball track 21 from the outlet position, completing a single-turn spiral motion and reversing cycle, thus realizing the continuous cyclic rolling of the steel ball 4 inside the ball nut 2.

[0026] Understandably, the insert-plate type installation method, compared to traditional end-cap type and internal tube type reversers, occupies less axial space, shortens the overall axial length of the ball nut, and makes the structure more compact, suitable for installation scenarios with limited space. Furthermore, the circulation of the steel ball 4 within the return channel 31 is an internal circulation form. The steel ball 4 always circulates inside the nut and does not protrude from the outer circle of the nut, resulting in a compact structure, no protruding parts during operation, and higher safety.

[0027] The sleeve 5 is fitted onto the outside of the insert-plate type steel ball reversing device 3 and the ball nut 2. The sleeve 5 is a hollow rotary sleeve structure, and its inner circumferential contour corresponds to and matches the outer circumferential contour of the ball nut 2. The axial length of the sleeve 5 at least covers the axial distribution range of the radial groove, ensuring that it can completely cover the outer opening of the radial groove. The inner circumferential surface of the sleeve 5 and the outer circumferential surface of the ball nut 2 are tightly fitted to achieve self-positioning and fixation, forming a closed constraint on the insert-plate type steel ball reversing device 3 from the radial outside.

[0028] The adjusting screw 6 is mounted on the ball nut 2. The shank of the adjusting screw 6 has an external thread structure, and the ball nut 2 has a corresponding threaded mounting hole. The adjusting screw 6 is threadedly engaged with the threaded mounting hole. By turning the adjusting screw 6, it can be fed and moved along its own axis. The end of the adjusting screw 6 abuts against the axial end face of the insert-plate type steel ball reversing device 3. When the adjusting screw 6 is fed inward, it can push the insert-plate type steel ball reversing device 3 to move axially within the radial groove 22, changing the axial position of the insert-plate type steel ball reversing device 3, thereby adjusting the axial relative position of the inlet and outlet of the return ball channel 31 and the ball track 21, and realizing the adjustment of their alignment accuracy.

[0029] In one embodiment, a threaded mounting hole is formed on the axial end face of the ball nut 2 and extends axially to the side wall of the radial groove 22. An adjusting screw 6 is screwed into the threaded mounting hole from the axially outer side of the ball nut 2, with its end extending into the radial groove 22 and abutting against the end face of the insert-type steel ball reversing device 3. The assembler can directly operate the adjusting screw 6 from the end of the ball nut 2 without disassembling other components, making the adjustment operation convenient.

[0030] It is understood that in this embodiment, the reversing device is configured as an axially movable insert structure, making the axial position of the ball return channel 31 adjustable. When there is a machining position deviation between the ball track 21 and the radial groove 22 of the ball nut, there is no need to rework the ball nut body; the deviation can be compensated simply by adjusting the screw to change the axial position of the reversing device, ensuring a smooth transition at the connection between the ball return channel 31 and the ball track 21. This structure effectively reduces the machining difficulty and precision requirements of the ball nut, improves the machining pass rate, and reduces production costs.

[0031] In the actual assembly process, steel balls 4 are first filled into the ball track 21 of the ball nut 2. Then, the insert-plate type steel ball reversing device 3 is inserted into the radial groove 22 from the radial outside of the ball nut 2, so that the inlet and outlet of the return ball channel 31 are initially aligned with the ball track 21. Then, the adjusting screw 6 is installed and pre-tightened. Next, the ball screw 1 or the ball nut 2 is rotated to test the smoothness of the steel ball 4 circulation. If there is any jamming or impact, the adjusting screw 6 is turned to finely adjust the axial position of the insert-plate type steel ball reversing device 3 until the steel ball 4 circulates smoothly without jamming, and the assembly and debugging are completed.

[0032] In some embodiments of this application, reference is made to Figure 2 As shown, the center curve of the internal ball return channel 31 of the insert-type steel ball reversing device 3 is a cam-like sine curve. This curve is defined using polar coordinates, and its polar coordinate equation is: .

[0033] In the formula, r is the radius of the polar coordinates of the return curve equation, representing the distance from any point on the curve to the origin of the polar coordinates; θ is the polar coordinate angular displacement, representing the polar angle corresponding to any point on the curve; h is the distance when steel ball 4 moves to the highest point, representing the maximum radial lift of the curve.

[0034] Furthermore, the curvature of the cam-like sinusoidal curve changes continuously along the entire curve path, without any abrupt curvature changes. When the steel ball 4 moves along this curve, its radial velocity and acceleration exhibit a continuous and smooth changing trend, without generating instantaneous impact loads. In one embodiment, the origin of the polar coordinates is located on the axis of the ball screw 1, and the start and end points of the curve are both located at the radial positions of the ball track 21, corresponding to the inlet and outlet of the return ball channel 31; the highest point of the curve is located on the radially outer side, corresponding to the position of the maximum radial displacement of the steel ball 4 during the reversal process. After the steel ball 4 enters the return ball channel 31 from the inlet, it gradually ascends radially outward along the cam-like sinusoidal curve, reaches the highest point, and then gradually returns radially inward, finally returning to the ball track 21 from the outlet. The motion trajectory of the entire reversal process is smooth and continuous.

[0035] In another implementation, the value of h can be adjusted according to the diameter of the steel ball 4 to ensure that the steel ball 4 has a suitable movement gap within the return channel 31, preventing both jamming and excessive movement due to excessive gap. This parameterized curve equation facilitates the rapid design of serialized products; only key parameters need to be adjusted to generate the corresponding return curve.

[0036] Optionally, the starting tangent direction of the cam-like sine curve is consistent with the motion tangent direction of the steel ball 4 in the ball track 21, and the ending tangent direction of the curve is consistent with the return motion tangent direction of the steel ball 4 in the ball track 21, so that the motion direction of the steel ball 4 can be naturally connected when entering and exiting the return ball channel 31, without any sudden change in direction, further reducing the impact at the connection point.

[0037] Understandably, the cam-like sinusoidal curve combines the lift characteristics of a cam curve with the smoothness of a sinusoidal curve, enabling the reversing process of steel ball 4 to be completed within a limited radial space. This adapts to the plate-like structure dimensions of the insert-type reversing device, ensuring its structural compactness. Simultaneously, the continuous and smooth curvature change effectively improves the stress state of steel ball 4, ensuring it remains under stable stress throughout the reversing process and reducing impact load damage to both the steel ball 4 and the channel wall. The lift and return processes of the cam-like sinusoidal curve are symmetrical, resulting in consistent motion characteristics of steel ball 4 during ascent and descent, uniform stress distribution, and preventing larger impacts on one side, thus making the reversing process more balanced.

[0038] In actual operation, the steel ball 4 enters the return ball channel 31 from the ball track 21 at a certain speed and moves in the opposite direction along a cam-like sinusoidal curve path. Due to the continuous change in the curvature of the curve, the radial velocity component of the steel ball 4 increases and decreases slowly, without generating abrupt inertial forces, resulting in a smooth and gentle reversal process. Therefore, the cam-like sinusoidal curve return ball channel 31 can effectively reduce reversal impact, reduce wear between the steel ball 4 and the inner wall of the channel, extend the service life of the reversing device and the steel ball 4, and at the same time reduce the vibration and noise generated during the reversal process, improving the running stability and acoustic performance of the ball screw pair.

[0039] In some embodiments of this application, reference is made to Figure 3 and Figure 4 As shown, the radial groove 22 on the ball nut 2 is a stepped radial groove. The radial cross-section of the stepped radial groove has a stepped structure. From the outer circumference of the ball nut 2 towards the inner circumference, the cross-sectional size of the groove gradually decreases, forming at least one stepped limiting surface. The insert-type steel ball reversing device 3 is embedded in the stepped radial groove. The outer circumference of the insert-type steel ball reversing device 3 is also set to a corresponding stepped shape, matching the stepped contour of the stepped radial groove. The stepped surface can radially limit the insert-type steel ball reversing device 3, preventing it from moving radially towards the inner cavity of the ball nut 2 and preventing the reversing device from falling inward.

[0040] Furthermore, the stepped surface of the stepped radial groove is a planar structure perpendicular to the radial direction of the ball nut 2. The corresponding stepped surface of the insert-type steel ball reversing device 3 fits into this stepped surface, achieving precise positioning in the radial direction and ensuring that the radial position of the return ball channel 31 corresponds precisely to the radial position of the ball track 21, avoiding radial misalignment. In one embodiment, the stepped radial groove is configured as a single-stage stepped structure, with a larger cross-sectional dimension for the outer groove section and a smaller cross-sectional dimension for the inner groove section, forming an annular stepped limiting surface between them. The insert-type steel ball reversing device 3 is correspondingly configured as a stepped plate-like structure that is wider on the outer side and narrower on the inner side. After installation, its stepped surface fits into the stepped surface of the groove, achieving radial positioning.

[0041] In another embodiment, the stepped radial groove can be configured as a multi-stage stepped structure to further improve the accuracy and reliability of radial positioning and limiting. This can be selected based on the wall thickness of the nut and the size of the reversing device. Furthermore, the fit of the stepped surface can also improve the heat dissipation capacity of the reversing device. The frictional heat generated during the operation of the reversing device can be transferred to the ball nut body through the stepped surface, and then dissipated outwards through the nut, improving the heat dissipation effect and delaying the aging of the lubricating grease.

[0042] A gap is left between the insert-plate type steel ball reversing device 3 and the axial side walls of the stepped radial groove. This gap is distributed along the axial direction of the ball nut 2, providing axial movement space for the insert-plate type steel ball reversing device 3 and ensuring the realization of the phase adjustment function. The axial side walls of the stepped radial groove are parallel planar structures, and the axial end faces of the insert-plate type steel ball reversing device 3 are also parallel planar structures. The two are set opposite each other and form a uniform gap, so that the reversing device will not get stuck during movement and the movement process is smooth.

[0043] The stepped groove structure achieves radial limiting and positioning of the reversing device through the stepped surface, solving the problems of easy detachment and poor radial positioning of the straight groove structure, and improving the reliability and radial alignment accuracy of the reversing device installation. At the same time, the gaps reserved on both sides of the axis preserve the axial adjustment capability of the reversing device, and the phase adjustment function will not be affected by the stepped structure, thus balancing positioning accuracy and adjustability.

[0044] During assembly, the insert-type steel ball reversing device 3 is inserted into the stepped radial groove from the radial outside of the ball nut 2 until its stepped surface is completely in contact with the stepped surface of the groove. At this point, the radial position of the reversing device is precisely defined, eliminating the need for additional radial alignment adjustments. Only minor adjustments to the axial position are required, simplifying the assembly and debugging process. During operation, the stepped surface can withstand the radial force on the reversing device, preventing it from shifting inward and ensuring long-term structural stability.

[0045] Therefore, this embodiment improves the radial positioning accuracy and installation reliability of the insert-type steel ball reversing device through the stepped radial groove structure design, while retaining the axial phase adjustment function, further improving the assembly efficiency and operational stability of the ball screw pair.

[0046] In some embodiments of this application, the adjusting screws 6 are configured as two sets, each set mounted on one of the two axial side walls of the stepped radial groove. Threaded mounting holes are provided on both axial side walls of the stepped radial groove, extending axially along the ball nut 2, with the outer side connected to the axial end face of the ball nut 2 and the inner side connected to the internal space of the stepped radial groove. The two sets of adjusting screws 6 are screwed into the threaded mounting holes on both sides, with their shank ends extending into the stepped radial groove. The ends of the two sets of adjusting screws 6 abut against the axial end faces of the insert-type steel ball reversing device 3, providing abutment constraint to the reversing device from both axial directions.

[0047] Furthermore, the axes of the two sets of adjusting screws 6 are collinear, and this common axis is parallel to the axial direction of the ball nut 2. This ensures that the adjusting force is transmitted along the axial direction and does not generate additional radial force, thus preventing radial offset or jamming of the reversing device due to the component force. In one embodiment, the specifications of the two sets of adjusting screws 6 are completely identical, with the same pitch and thread precision, facilitating synchronous adjustment on both sides and ensuring precise control of the adjustment amount.

[0048] When adjusting the axial position of the insert-type steel ball reversing device 3, a double-sided adjustment method is used: If the reversing device needs to be moved to the left, first loosen the left adjusting screw 6, causing its end to move backward to the left, leaving room for movement; then slowly tighten the right adjusting screw 6, causing its end to move to the left, pushing the insert-type steel ball reversing device 3 to move axially to the left; after moving to the target position, tighten the left adjusting screw 6 again, so that its end abuts against the left end face of the reversing device, achieving double-sided locking. Similarly, when moving to the right, first loosen the right screw, then tighten the left screw, and finally lock both sides.

[0049] Optionally, the head of the adjusting screw 6 can be configured with an internal hexagonal head for easy tightening with a standard internal hex wrench, and the head can be recessed into the countersunk hole on the end face of the ball nut 2 to avoid protruding from the nut end face and affecting the overall installation. The adjusting screw 6 can be made of high-strength steel to ensure sufficient structural strength to withstand the adjustment thrust and vibration loads during operation without deformation or breakage.

[0050] Understandably, the dual-sided adjusting screws enable bidirectional active adjustment of the reversing device. The adjustment direction is controllable, and the adjustment amount can be precisely controlled. No additional tools or the force of the steel ball 4 are required for resetting, significantly improving the ease of operation and efficiency of phase adjustment. Simultaneously, the dual-sided locking structure firmly fixes the reversing device to the target axial position. With screws limiting movement in both directions, axial movement will not occur during operation due to vibration, impact, or other factors. This ensures long-term alignment accuracy between the return channel 31 and the ball track 21, guaranteeing the smooth and stable circulation of the steel ball 4.

[0051] In some embodiments of this application, the adjusting screw 6 has a fine-pitch structure, meaning its thread is fine-pitch. Compared to a coarse-pitch thread of the same specification, the fine-pitch thread has a smaller pitch and a shallower thread profile. When the adjusting screw 6 is turned, the axial feed per revolution is smaller, thus enabling more precise axial position adjustment. By coordinating the adjustment of two sets of fine-pitch adjusting screws 6, the axial position of the insert-type steel ball reversing device 3 can be finely adjusted at the micrometer level, thereby precisely adjusting the coaxiality of the return ball channel 31 and the ball track 21, ensuring that their central axes are highly aligned.

[0052] Furthermore, when there is a machining deviation in the position of the threaded ball track 21 and the radial groove 22 on the ball nut 2, or a machining deviation in the return ball channel 31 and the axial positioning surface of the insert-type steel ball reversing device 3, or both deviations exist simultaneously, compensation can be made through the fine-pitch adjusting screw. In one embodiment, by adjusting with the cooperation of the fine-pitch adjusting screws on both sides, the axial symmetry of the return ball channel 31 and the ball track 21 can be controlled within 0.01mm, so that the connection between the two can achieve a smooth transition without steps, and the steel ball 4 will not produce a noticeable impact when passing through.

[0053] Fine-pitch threads inherently possess superior self-locking properties and a smaller thread helix angle, making them less prone to loosening under external forces such as vibration and impact. After adjustment and tightening, adjusting screw 6 can maintain the current feed position for a long time without unraveling due to operational vibration, ensuring that the positional accuracy of the reversing device can be maintained stably over a long period without the need for frequent secondary calibration.

[0054] In some embodiments of this application, the insert-type steel ball reversing device 3 has 3 to 6 return ball channels 31. The multiple return ball channels 31 are evenly spaced along the circumferential direction of the insert-type steel ball reversing device 3. Each return ball channel 31 is an independent and complete reversing channel, corresponding to an independent steel ball 4 circulation loop. The inlet and outlet of each return ball channel 31 are respectively connected to the ball track 21 corresponding to the inner circumferential surface of the ball nut 2, forming a multi-row parallel steel ball 4 circulation system, which jointly bears the transmission load.

[0055] Furthermore, the structural form of each ball return channel 31 is consistent with the curve parameters, ensuring that the motion characteristics of each loop are the same, and the circulation speed of the steel ball 4 in each loop is consistent, preventing motion interference or uneven load between different loops. In one embodiment, the number of ball return channels 31 can be selected according to the rated load requirements of the ball screw pair. For light-load, precision transmission scenarios, a structure with 3 ball return channels 31 can be selected; for medium-heavy-load scenarios, a structure with 4 to 5 ball return channels 31 can be selected; for heavy-load scenarios, a structure with 6 ball return channels 31 can be selected, thereby increasing the overall load-bearing capacity by increasing the number of loops.

[0056] The evenly distributed structure of multiple return channels 31 allows the load to be evenly distributed across each row of steel balls 4, significantly reducing the contact stress on each individual steel ball 4. This effectively delays fatigue wear between the raceway and the steel balls 4, extending the rated life of the ball screw assembly. Simultaneously, the even load distribution across multiple rows of steel balls 4 also ensures a more balanced stress on the ball nut 2, preventing nut deformation due to uneven loading and improving the smoothness and precision retention of the transmission.

[0057] Optionally, multiple return ball channels 31 can be integrally machined on the insert-type steel ball reversing device 3 to ensure the positional accuracy between channels and ensure consistent alignment of each circuit. The insert-type structure makes the integration of multiple circuits more convenient. Compared with the traditional structure of multiple independent inverters, the integrated insert-type reversing device is simpler to assemble. All circuit inverters can be installed in one insertion, thereby improving assembly efficiency.

[0058] In some embodiments of this application, reference is made to Figure 5 As shown, the phase-adjustable insert-type ball screw assembly also includes a lubrication and sealing unit 7. Mounting holes are provided on both axial end faces of the ball nut 2. These mounting holes are circular grooves extending inward along the axial direction of the ball nut 2, coaxially aligned with the inner cavity of the ball nut 2. The inner diameter of the mounting holes matches the outer diameter of the lubrication and sealing unit 7. The lubrication and sealing unit 7 is installed within the mounting holes, sealing the inner cavity ports of the ball nut 2 from both axial ends, thus providing both lubrication and sealing functions.

[0059] Reference Figure 6 As shown, the lubrication and sealing unit 7 includes two parts: a lubricating element 71 and a sealing element 72. The lubricating element 71 is disposed on the inner side near the ball nut 2, and the sealing element 72 is located on the outer side of the lubricating element 71. The two are arranged sequentially along the axial direction to form a composite lubrication and sealing assembly. In one embodiment, the lubricating element 71 and the sealing element 72 are coaxial annular structures, with their inner holes for the ball screw 1 to pass through, and the inner hole walls are disposed opposite to the outer peripheral surface of the ball screw 1.

[0060] The lubricating element 71 is located on the inner side, close to the area of ​​the steel ball 4 and the raceway 21 inside the ball nut 2, and can supply lubricating medium to the raceway and the steel ball 4 to achieve continuous lubrication. The sealing element 72 is located on the outer side, at the outer end face of the lubricating element 71, and is used to seal the outer port of the mounting hole to prevent external contaminants from entering, while preventing the internal lubricating medium from leaking outward.

[0061] Optionally, the lubrication sealing unit 7 can be fixed in the mounting hole of the ball nut 2 by a radial fastening screw. The outer circumferential surface of the ball nut 2 has a threaded hole that radially extends to the mounting hole. The fastening screw is screwed into the threaded hole from the radial side, and its end abuts against the outer circumferential surface of the lubrication sealing unit 7. The lubrication sealing unit 7 is fixed by radial tightening, preventing it from axially falling out of the mounting hole. This fixing method is convenient for disassembly and assembly, and facilitates future replacement and maintenance.

[0062] Understandably, integrating lubrication and sealing units at both ends of the ball nut combines lubrication and sealing functions into one, achieving continuous internal lubrication while effectively protecting against external damage, significantly reducing the frequency of external maintenance. The inner lubricating element continuously supplies lubricating medium to the friction pair, ensuring that the raceway and steel ball 4 are always in a good lubricated state, reducing friction and wear; the outer sealing element creates a closed internal environment, preventing the intrusion of external dust and debris, while also preventing grease leakage and maintaining a stable internal lubrication environment.

[0063] During actual operation, the lubricating component 71 slowly releases the lubricating medium to lubricate the passing steel balls 4 and raceways. The lubricated steel balls 4 carry the grease into the internal ball track 21, achieving lubrication of the entire circulation loop. The sealing component 72 remains in contact with the surface of the ball screw 1, maintaining a sealing effect with the movement of the screw, preventing external contaminants from entering, and simultaneously preventing internal grease from leaking outward along the screw surface.

[0064] In some embodiments of this application, the lubricating element 71 is made of polyurethane foam. The polyurethane foam forms a dense pore structure inside through a foaming process. The pores are uniformly distributed in a honeycomb pattern and are filled with grease. The dense pore structure can store a large amount of grease, forming an oil reservoir. During the operation of the ball screw pair, the grease in the pores will slowly precipitate out due to the temperature changes caused by the friction of the steel balls 4 and the vibration during operation, continuously supplying the raceway and steel balls 4, thus achieving a long-term self-lubricating effect.

[0065] Furthermore, a V-shaped cavity 73 is formed in the middle of the lubricating component 71. The V-shaped cavity 73 extends circumferentially along the lubricating component 71, and is also filled with grease to further increase the grease storage capacity and extend the lubrication cycle. The volume V of the V-shaped cavity 73 satisfies the calculation formula: .

[0066] In the formula, Where is the diameter of steel ball 4 in mm, L is the lifespan of the ball screw assembly in years, and k is a calculation coefficient. This formula allows for the matching of the corresponding V-shaped cavity volume based on the diameter of steel ball 4 and the product's design life, ensuring that the total grease storage capacity meets the lubrication requirements throughout the design lifespan, achieving maintenance-free operation.

[0067] In one embodiment, the honeycomb porous structure of the lubricating component 71 not only has oil storage and lubrication functions, but also has good sound absorption and vibration reduction effects. When the vibration and noise generated during the operation of the steel ball 4 are transmitted to the lubricating component, the sound waves will undergo multiple reflections, refractions and frictions inside the pores after entering the porous structure. The sound energy is gradually absorbed and attenuated, thereby playing a role in noise reduction and effectively reducing the operating noise of the ball screw pair.

[0068] Optionally, the opening of the V-shaped cavity 73 faces inward towards the ball nut 2, allowing the grease in the cavity to penetrate and replenish the inner pore structure more smoothly, ensuring the continuity of grease precipitation, avoiding the situation where the grease in the pores is exhausted and the grease in the cavity cannot be replenished, and improving the reliability and durability of lubrication.

[0069] In this embodiment, polyurethane foam material is used to make the lubricating component. Its porous structure simultaneously achieves the dual functions of oil storage and lubrication as well as noise reduction, eliminating the need for additional noise reduction components and simplifying the structure. The addition of the V-shaped cavity increases the grease storage capacity without significantly increasing the overall volume of the lubricating component. Furthermore, the oil storage capacity is related to the diameter of the steel ball and the design life, which can be specifically matched to the lubrication requirements of different product specifications, ensuring that no additional grease needs to be replenished within the design life, thus achieving maintenance-free operation.

[0070] In some embodiments of this application, the seal 72 is a spiral polytetrafluoroethylene (PTFE) sealing sheet. The seal 72 has an overall annular sheet structure with a spiral inner edge that corresponds to and matches the spiral raceway shape on the outer periphery of the ball screw 1. The seal 72 is fixed to the outer end face of the lubricating element 71 and is coaxially arranged with the lubricating element 71. Its inner spiral surface is tightly fitted to the spiral raceway surface of the ball screw 1, forming a close-fitting seal.

[0071] Specifically, PTFE material possesses excellent self-lubricating properties and wear resistance, with an extremely low coefficient of friction. When in contact with the ball screw surface, the wear is minimal, maintaining the accuracy of the sealing profile and ensuring a good sealing effect over a long period. Furthermore, PTFE exhibits good corrosion resistance, adapting to various working environments without being corroded or deteriorated by lubricating grease or external environmental media.

[0072] In actual use, the spiral inner edge structure can be embedded in the spiral raceway groove of the ball screw 1 and fit completely with the surface of the raceway, eliminating the gap between the ordinary flat hole seal and the spiral raceway. This effectively prevents grease from leaking outward along the spiral raceway and also prevents external dust and debris from entering the nut through the raceway groove, greatly improving the sealing effect.

[0073] Optionally, the seal 72 can be fixed to the outer end face of the lubricant 71 by adhesive bonding, ensuring a firm connection and simple assembly; alternatively, it can be inserted into a groove on the outer end face of the lubricant by embedding, facilitating individual replacement of the seal later. The thickness of the seal can be adjusted according to sealing requirements and installation space to ensure sufficient structural strength and sealing elasticity.

[0074] During actual operation, when the ball screw 1 and ball nut 2 rotate relative to each other, the inner edge of the spiral sealing plate slides relative to each other along the spiral raceway of the screw, always maintaining a close fit and continuously performing a sealing function. The low friction characteristics of PTFE ensure that the seal does not generate significant additional resistance to the movement of the screw, ensuring that the transmission efficiency is not affected. Therefore, by selecting a spiral structure for the seal 72, it can adapt to the spiral surface characteristics of the screw, eliminate sealing gaps, achieve full-circumferential sealing, effectively solve the problem of poor compatibility between ordinary seals and screw raceways, and significantly improve sealing reliability. The use of PTFE material can greatly reduce friction and wear between the seal and the screw, extend the service life of the seal, ensure long-term effective sealing protection, and prevent grease leakage and contaminant intrusion due to seal failure.

[0075] Therefore, this embodiment improves the compatibility and fit between the sealing structure and the ball screw by designing a spiral polytetrafluoroethylene sealing sheet, enhances the sealing effect, improves the wear resistance and service life of the sealing component, ensures the stability of the internal lubrication environment of the nut, and further extends the maintenance-free cycle of the ball screw pair.

[0076] In some embodiments of this application, the axial clearance between the insert-type steel ball reversing device 3 and the stepped radial groove is 1 ± 0.02 mm. This clearance represents the total axial movement of the insert-type steel ball reversing device 3 within the stepped radial groove, i.e., the total adjustable stroke of the reversing device. This numerical range was determined after comprehensively considering the range of conventional machining deviations and structural stability requirements, thus balancing adjustability and structural rigidity.

[0077] Furthermore, the total adjustment of 1mm can cover the comprehensive axial deviation caused by various factors such as the positional deviation between the ball nut track 21 and the radial groove 22, the positional deviation between the return ball channel 31 of the reversing device and the positioning surface, and heat treatment deformation under conventional machining processes. This meets the deviation compensation requirements in most scenarios and ensures that the phase adjustment function can play an effective role. The clearance tolerance of ±0.02mm ensures the consistency of clearance dimensions during mass production, facilitates the interchangeability and assembly of parts, and improves the efficiency and consistency of mass production.

[0078] In one embodiment, the axial clearance is determined by the difference between the axial groove width of the stepped radial groove and the axial thickness of the insert-type steel ball reversing device 3. By controlling the dimensional accuracy of the groove width and the thickness of the reversing device during processing, the clearance can be ensured to be within the range of 1 ± 0.02 mm. The adjustable stroke of the adjusting screw 6 is adapted to this total clearance, and the maximum feed of the screw can cover the entire clearance range, ensuring that the reversing device can be adjusted to any position within the clearance.

[0079] Understandably, controlling the axial clearance within the range of 1±0.02mm ensures sufficient phase adjustment stroke to effectively compensate for various machining deviations, while avoiding problems such as insufficient structural rigidity and axial movement of the reversing device caused by excessive clearance. This achieves an optimal balance between adjustment function and structural stability. The appropriate clearance also ensures that the reversing device is firmly fixed after the adjusting screws are tightened, providing sufficient vibration resistance and preventing positional shift during operation.

[0080] Based on the above embodiments, the overall assembly and use process of the phase-adjustable insert-plate type ball screw pair provided in this application is as follows: During assembly, firstly, steel balls 4 are filled into the ball track 21 of the ball nut 2. Then, the insert-plate type steel ball reversing device 3 is installed from the radial outside into the stepped radial groove, so that the return ball channel 31 is initially aligned with the ball track 21. Subsequently, adjusting screws 6 are installed on both sides of the ball nut 2. The axial position of the reversing device is finely adjusted by the fine-thread adjusting screws 6 to ensure that the return ball channel 31 is precisely aligned with the ball track 21, ensuring smooth circulation of the steel balls 4. After adjustment, the adjusting screws on both sides are tightened. The sleeve 5 is axially fitted onto the corresponding area on the outer periphery of the ball nut 2, so that the inner circumferential surface of the sleeve 5 is tightly fitted with the outer circumferential surface of the ball nut 2. Then, the lubrication sealing unit 7 is installed in the mounting holes at both ends of the ball nut 2 and fixed with radial screws to complete the overall assembly. Finally, the ball nut 2 is screwed into the ball screw 1 to form a complete ball screw pair transmission structure.

[0081] During operation, the ball screw 1 and ball nut 2 rotate relative to each other, and the steel ball 4 rolls along the raceway 21 and completes the cycle reversal through the return ball channel 31 of the insert-type steel ball reversing device 3, thus realizing the transmission function. The lubricating element 71 of the lubrication and sealing unit 7 continuously releases grease to lubricate the steel ball 4 and the raceway, while the porous structure absorbs vibration noise; the sealing element 72 achieves sealing against dust and leakage, maintaining the stability of the internal environment. When the accuracy decreases after long-term operation, the position of the reversing device can be finely adjusted again by adjusting the screw 6 to restore the centering accuracy.

[0082] Other embodiments of this disclosure will readily occur to those skilled in the art upon consideration of the disclosure in the specification and the embodiments. This application is intended to cover any variations, uses, or adaptations of this disclosure that follow the general principles of this disclosure and include common knowledge or customary techniques in the art not disclosed herein.

Claims

1. A phase-adjustable insert-plate type ball screw pair, characterized in that, include: Ball screw (1); A ball nut (2) is sleeved on the outside of the ball screw (1). The inner circumferential surface of the ball nut (2) is provided with a ball track (21), and the radial direction of the ball nut (2) is provided with a radial groove (22) that extends to the ball track (21). A plate-type steel ball reversing device (3) is installed in the radial groove (22). The inside of the plate-type steel ball reversing device (3) is provided with a ball return channel (31). The inlet and outlet of the ball return channel (31) are connected to the ball track (21). Sleeve (5) is sleeved on the outside of the insert-type steel ball reversing device (3) and the ball nut (2); An adjusting screw (6) is mounted on the ball nut (2), and the end of the adjusting screw (6) abuts against the insert-type steel ball reversing device (3) to adjust the axial position of the insert-type steel ball reversing device (3) in the radial groove (22).

2. The phase-adjustable insert-plate type ball screw pair according to claim 1, characterized in that, The center curve of the ball return channel (31) is a cam-like sine curve.

3. The phase-adjustable insert-plate type ball screw pair according to claim 1, characterized in that, The radial groove (22) is a stepped radial groove; The insert-type steel ball reversing device (3) is embedded in the stepped radial groove, and there is a gap between the insert-type steel ball reversing device (3) and the axial side walls of the stepped radial groove.

4. The phase-adjustable insert-plate type ball screw pair according to claim 3, characterized in that, The adjusting screws (6) are configured in two sets; The two sets of adjusting screws (6) are respectively installed on the two side walls of the stepped radial groove along the axial direction, and the ends of the two sets of adjusting screws (6) respectively abut against the two end faces of the insert-type steel ball reversing device (3) along the axial direction.

5. The phase-adjustable insert-plate type ball screw pair according to claim 4, characterized in that, The adjusting screw (6) has a fine-tooth structure. By adjusting the two sets of adjusting screws (6), the coaxiality of the ball return channel (31) and the ball track (21) can be adjusted.

6. The phase-adjustable insert-plate type ball screw pair according to claim 1, characterized in that, The insert-type steel ball reversing device (3) has 3 to 6 ball return channels (31).

7. The phase-adjustable insert-plate type ball screw pair according to claim 1, characterized in that, It also includes a lubrication and sealing unit (7), wherein mounting holes are provided on both axial end faces of the ball nut (2), and the lubrication and sealing unit (7) is installed in the mounting holes; The lubrication and sealing unit (7) includes a lubricating element (71) near the inside of the ball nut (2) and a sealing element (72) on the outside.

8. The phase-adjustable insert-plate type ball screw pair according to claim 7, characterized in that, The lubricant (71) is made of polyurethane foam material; The lubricating component (71) has pores inside, the pores are filled with grease, and the lubricating component (71) has a V-shaped cavity (73). The volume V of the V-shaped cavity (73) satisfies the following formula: ； In the formula, is the diameter of the steel ball (4) in mm, L is the life of the ball screw pair in years, and k is the calculation coefficient.

9. The phase-adjustable insert-plate type ball screw pair according to claim 8, characterized in that, The sealing element (72) is a spiral polytetrafluoroethylene sealing sheet, and the sealing element (72) is fixed to the outer end face of the lubricating element (71).

10. The phase-adjustable insert-plate type ball screw pair according to claim 3, characterized in that, The axial clearance between the insert-type steel ball reversing device (3) and the stepped radial groove is 1±0.02mm.

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