A reverse type ball screw pair

Abstract

The application relates to a reverse type ball screw pair, belonging to the technical field of ball screw pairs, which comprises a screw rod, a nut, balls and a returner, the screw rod is provided with a mounting groove, the returner is located in the mounting groove, the returner is provided with a return groove, the threaded grooves of the screw rod and the nut and the return groove form a return channel, and the balls are located in the return channel; a plurality of groups of positioning plates are fixedly arranged in the mounting groove, the number of positioning plates in each group is two, a plurality of positioning grooves are arranged on the side of the returner facing the mounting groove, the positioning plates and the positioning grooves are arranged in correspondence, the positioning plates are located in the positioning grooves, and a clamping assembly is arranged at the connecting position of the returner and the screw rod, the clamping assembly can fix the returner on the screw rod. The application has the effects of quick and simple assembly and more reliable equipment operation.

Description

Technical Field

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

[0002] A reverse ball screw assembly is a precision transmission mechanism that converts rotary motion into linear motion. In a reverse ball screw assembly, a return mechanism is typically installed between the screw and the nut. This return mechanism contains internal moving grooves or return channels for ball reversal, guiding and switching the balls towards the return path, ensuring smooth transitions between multiple circulation paths.

[0003] Existing ball screw return devices are typically placed in pre-drilled mounting slots on the screw, relying solely on ball bearings for positioning. However, ball screw pairs require high transmission precision, and slight axial or radial deviations may occur during actual assembly. Furthermore, during long-term use, the return device may experience displacement or attitude deflection due to continuous alternating loads, vibrations, and impacts. When the return device shifts position, the spatial position between its internal moving slot and the threaded raceways of the screw and nut also shifts. The originally precisely aligned ball inlet and outlet channels may become misaligned or offset, preventing a smooth transition of the balls as they enter the return device or the threaded raceways. This can lead to ball jamming at channel intersections, discontinuous ball circulation, or even complete failure of the balls to enter the circulation path, resulting in localized momentary jamming or stagnation, ultimately affecting the reliability and safety of the equipment. Summary of the Invention

[0004] To achieve quick and easy assembly and more reliable equipment operation, this application provides a reverse ball screw pair.

[0005] This application provides a reverse-type ball screw pair. The technical solution adopted is as follows: A reverse ball screw assembly includes a screw, a nut, balls, and a return mechanism. The screw has a mounting groove, the return mechanism is located in the mounting groove, and the return mechanism has a return groove. The thread grooves of the screw and the nut, along with the return groove, form a return channel, and the balls are located in the return channel. Several sets of positioning plates are fixedly installed in the mounting slot, with two positioning plates in each set. Several positioning slots are opened on the side of the return device facing the mounting slot. The positioning plates are arranged corresponding to the positioning slots and are located in the positioning slots. A snap-fit ​​component is provided at the connection between the return device and the lead screw, which can fix the return device on the lead screw.

[0006] By adopting the above technical solution, during the assembly process, the return unit faces the mounting groove so that the two positioning plates are inserted into the positioning groove, realizing precise axial limiting and rapid positioning of the return unit, improving the assembly consistency and positional accuracy between the return unit and the lead screw. At the same time, the snap-fit ​​component at the connection between the return unit and the lead screw enables the return unit to be accurately positioned in the axial direction and reliably locked in the radial direction, enhancing the structural stability of the return unit during operation and preventing radial displacement under vibration, impact, or long-term operating load. The synergistic effect of the positioning plate, positioning groove, and snap-fit ​​component effectively constrains the return unit in both the axial and radial directions, significantly reducing the risk of relative positional displacement between the return unit, the lead screw, and the nut thread groove, ensuring that the return groove and the thread groove always maintain a good alignment relationship, thereby improving the smoothness of ball circulation, reducing rolling resistance and jamming, and improving the reliability and stability of the reverse ball screw pair operation.

[0007] Optionally, the return device has multiple return slots, which are arranged parallel to each other along the length of the return device.

[0008] By adopting the above technical solution, multiple return grooves are set on the return device, enabling the balls to circulate in multiple independent return channels. Multiple return channels can share the load pressure of a single channel, improving the overall load-bearing capacity of the ball circulation system. At the same time, the return grooves on the return device can be opened according to actual usage requirements, adapting to different numbers or different arrangement of thread raceways, enhancing the adaptability and expandability of the structural design, and making the reverse ball screw pair more versatile and expandable under different specifications or different load conditions.

[0009] Optionally, the return groove is smoothly connected to the adjacent threaded groove on the lead screw.

[0010] By adopting the above technical solution, the smooth connection structure of the return groove gives it good force balance, which helps the balls maintain a stable motion trajectory during entry and exit from the return groove, reducing local stress concentration or uneven rolling caused by structural asymmetry. The return groove is connected to a threaded groove to form a continuous closed ball circulation path, making the balls more evenly stressed during circulation, reducing the load pressure of each return channel, and making the rolling state more stable. This helps to improve the overall load distribution capacity and transmission stability, and enhance the load-bearing capacity and operational reliability of the reverse ball screw pair.

[0011] Optionally, the snap-fit ​​assembly includes a first snap-fit ​​block and a second snap-fit ​​block, the first snap-fit ​​block being located on the side of the return unit facing the mounting groove, and the end of the first snap-fit ​​block facing the second snap-fit ​​block being provided with a first guide surface; The mounting slot has a receiving groove, and a guide seat is fixedly installed in the receiving groove. The second snap-fit ​​block is slidably connected in the guide seat. A third snap-fit ​​block is fixedly installed on the side of the second snap-fit ​​block facing the first snap-fit ​​block. A second guide surface is provided on the end of the third snap-fit ​​block facing the first guide surface. A first return spring is sleeved on the second snap-fit ​​block. The first return spring is used to drive the second snap-fit ​​block to return to its original position. When the return device is installed on the lead screw, the first snap-fit ​​block and the third snap-fit ​​block snap together.

[0012] By adopting the above technical solution, when the return unit is installed on the mounting slot, the first guide surface of the first locking block pushes the second guide surface of the third locking block to form a progressive guiding contact. Under the guiding action, the second locking block compresses the first return spring until the first return spring pushes the second locking block, causing the third locking block to engage with the first locking block. This improves the smoothness and operability of the assembly process. After the return unit is installed in place, under the elastic restoring force of the first return spring, the second locking block pushes the third locking block back to its original position, enabling the first locking block and the third locking block to reliably engage. This forms a stable locking effect on the return unit, improves the fixing reliability of the return unit in the screw mounting slot, prevents it from loosening or shifting during operation, and enhances the overall structural stability and operational reliability.

[0013] Optionally, the receiving groove extends through the end of the return device, and a pushing block is fixedly provided at the end of the second latching block away from the guide seat. The pushing block can push the second latching block to separate the first latching block from the third latching block.

[0014] By adopting the above technical solution, when the return unit needs to be disassembled or replaced, the push block can be pushed to move the second locking block, thereby compressing the first reset spring and causing the third locking block to move synchronously with the second locking block, releasing the locking state between the third locking block and the first locking block, realizing the rapid separation of the locking structure, improving the convenience of maintenance and replacement, and helping to improve assembly and maintenance efficiency and reliability.

[0015] Optionally, a sealing cap is also included, wherein the nut has a through hole, the sealing cap is threadedly connected to the through hole, and the ball can enter the return channel through the through hole.

[0016] By adopting the above technical solution, the sealing cover and the through hole are connected by a threaded structure, which makes the sealing cover and the through hole form a reliable closed through hole, reducing the leakage of external dust, impurities or lubricating media into or out of the ball circulation channel. The nut ensures the sealing of the structure while having a detachable opening function. When opened, the ball can be assembled. The ball can be put into the return channel through the through hole, which facilitates the installation and filling of the ball and improves the convenience of assembly operation.

[0017] Optionally, it also includes a fixing plate, on which a connecting cylinder is provided, and a blocking member is slidably provided inside the connecting cylinder. The blocking member can block the end of the connecting cylinder away from the fixing plate. A reset tension spring is connected to the end of the blocking member facing the fixing plate, and a driving assembly is provided on the connecting cylinder. An extension tube is provided at the end of the nut near the connecting tube. A first stop is slidably provided inside the extension tube. The first stop can block one end of the extension tube facing the fixed plate. A fixed sleeve is fixedly provided inside the extension tube. A sliding sleeve is fixedly provided on the first stop. The sliding sleeve is slidably connected inside the fixed sleeve. A second return spring is provided on the first stop. The other end of the second return spring is fixed inside the fixed sleeve. The drive component drives the blocking member to push the first stop, thereby connecting the connecting cylinder and the extension cylinder.

[0018] By adopting the above technical solution, when it is necessary to replenish lubricating oil or cooling medium between the nut and the lead screw, the connecting cylinder and the extension cylinder are connected. The blocking component can be driven to move by the drive assembly, so that it overcomes the elastic force of the reset spring and applies a thrust to the first stop block in the extension cylinder, pushing the first stop block to compress the second reset spring. The sliding sleeve slides in the fixed sleeve for guidance and limitation. The first stop block retracts into the extension cylinder, and the blocking component gradually extends into the extension cylinder, realizing the docking and connection between the connecting cylinder and the extension cylinder. During reset, the reset spring and the second reset spring drive the blocking component and the first stop block to reset and re-close the channel.

[0019] Optionally, the driving assembly includes a connecting sleeve, a first magnet, and a second magnet. The connecting sleeve is sleeved outside the connecting cylinder and can slide from the connecting cylinder to the extension cylinder. The first magnet is fixedly mounted on the connecting sleeve. The blocking member includes a push rod and a second stop. The push rod is fixedly connected to the second stop, and the second magnet is fixedly mounted on the push rod. The first magnet and the second magnet are correspondingly arranged. When the connecting sleeve is pushed, the push rod moves synchronously with the connecting sleeve.

[0020] By adopting the above technical solution, the first magnet and the second magnet generate a magnetic attraction when aligned, so that when the connecting sleeve slides from the connecting cylinder to the extension cylinder, the first magnet on the connecting sleeve attracts the second magnet, and simultaneously drives the push rod to push towards the extension cylinder, so that the blocking component can be pushed to the target position more smoothly and reliably and cooperate with the first stop to achieve channel connection.

[0021] Optionally, a first sealing ring is provided at the port of the extension cylinder adjacent to the first stop, and a second sealing ring is provided at the port of the connecting cylinder adjacent to the second stop.

[0022] By adopting the above technical solution, the first sealing ring and the second sealing ring prevent lubricating oil or coolant from being exposed during transportation and in a static state, while blocking external dust and impurities from entering the internal flow channel, thereby improving the overall sealing performance.

[0023] Optionally, an elastic snap-fit ​​block is fixedly provided on the connecting sleeve, a snap-fit ​​protrusion is fixedly provided on the extension cylinder, a third guide surface is provided on the side of the elastic snap-fit ​​block facing the snap-fit ​​protrusion, a fourth guide surface is provided on the side of the snap-fit ​​protrusion facing the elastic snap-fit ​​block, a reset block is sleeved on the extension cylinder, the reset block is slidably connected to the extension cylinder, and a fifth guide surface is provided on the side of the reset block away from the snap-fit ​​protrusion. The connecting sleeve pushes the elastic locking block, enabling the elastic locking block to engage with the locking protrusion. When the connecting sleeve pushes the elastic locking block again, the third guide surface allows the elastic locking block to slide onto the fifth guide surface. When the connecting sleeve resets, it causes the reset block to abut against the locking protrusion, thus separating the elastic locking block from the locking protrusion.

[0024] By adopting the above technical solution, the connecting sleeve is pushed to move the elastic locking block toward the locking protrusion. The third guide surface and the fourth guide surface cooperate to make the elastic locking block and the locking protrusion lock together, ensuring stable fixation after the locking connection, and realizing rapid positioning and reliable locking. The connecting sleeve is pushed again to move the elastic locking block toward the reset block. The third guide surface makes the elastic locking block slide on the fifth guide surface, stopping the push on the connecting sleeve. The connecting sleeve drives the reset block to abut against the locking protrusion, so that the elastic locking block and the locking protrusion can be unlocked and separated.

[0025] In summary, this application includes at least one of the following beneficial technical effects: 1. The return unit faces the mounting slot so that the two positioning plates can be inserted into the positioning slot, realizing precise axial limiting and rapid positioning of the return unit, improving the assembly position accuracy between the return unit and the lead screw. At the same time, the snap-fit ​​assembly enables the return unit to be accurately positioned in the axial direction and can be reliably locked in the radial direction, enhancing the structural stability of the return unit during operation and preventing radial displacement under vibration, impact or long-term operating load.

[0026] 2. Multiple return grooves enable the balls to circulate in multiple independent return channels. Multiple return channels can share the load pressure of a single channel, improving the overall load-bearing capacity of the ball circulation system. At the same time, the return grooves on the returner can be opened according to actual usage requirements to adapt to different numbers or different arrangement of thread raceways, enhancing the adaptability and expandability of the structural design.

[0027] 3. The return groove has a centrally symmetrical structure, which gives it good stress balance. This helps the balls maintain a stable trajectory when entering and exiting the return groove, and reduces local stress concentration or uneven rolling caused by structural asymmetry.

[0028] 4. The sealing cap and the through hole adopt a threaded connection structure, which makes the sealing cap and the through hole form a reliable closed through hole, reducing the leakage of external dust, impurities or lubricating media into or out of the ball circulation channel. The nut ensures the sealing of the structure and has a detachable opening function. When opened, the ball can be assembled. The ball can be put into the return channel through the through hole, which facilitates the installation and filling of the ball and improves the convenience of assembly operation.

[0029] 5. When it is necessary to replenish the lubricating oil or cooling medium between the nut and the lead screw, the ports of the connecting cylinder and the extension cylinder are connected. The blocking component can be driven to move by the drive assembly, and a thrust is applied to the first stop block in the extension cylinder to push the first stop block. The sliding sleeve slides in the fixed sleeve for guidance and limitation. The first stop block retracts into the extension cylinder, and the blocking component gradually extends into the extension cylinder to realize the docking and connection between the connecting cylinder and the extension cylinder. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the overall structure of an embodiment of this application.

[0031] Figure 2 This is a schematic diagram illustrating the structure of the return groove and the lead screw in an embodiment of this application.

[0032] Figure 3 This is a cross-sectional structural diagram illustrating the return channel in an embodiment of this application.

[0033] Figure 4 This is a schematic diagram illustrating the structure of the positioning plate and positioning groove in an embodiment of this application.

[0034] Figure 5 This is a cross-sectional structural diagram illustrating the snap-fit ​​assembly in an embodiment of this application.

[0035] Figure 6 yes Figure 5 An enlarged schematic diagram of part A in the middle.

[0036] Figure 7 This is a cross-sectional structural diagram illustrating the blocking member and the first stop block in an embodiment of this application.

[0037] Figure 8 yes Figure 7 Enlarged diagram of part B.

[0038] Explanation of reference numerals in the attached drawings: 1. Lead screw; 11. Mounting groove; 111. Receiving groove; 112. Guide seat; 12. Return channel; 13. Positioning plate; 2. Nut; 21. Sealing cap; 22. Through hole; 3. Ball bearing; 4. Return device; 41. Return groove; 42. Positioning groove; 5. Snap-fit ​​assembly; 51. First snap-fit ​​block; 511. First guide surface; 52. Second snap-fit ​​block; 53. Third snap-fit ​​block; 531. Second guide surface; 54. First return spring; 55. Push block; 61. Fixing plate; 62. Connector 621. Second sealing ring; 63. Reset spring; 64. Extension cylinder; 641. First sealing ring; 65. First stop block; 66. Fixed sleeve; 67. Sliding sleeve; 68. Second reset spring; 7. Blocking element; 71. Push rod; 72. Second stop block; 8. Drive assembly; 81. Connecting sleeve; 82. First magnet; 83. Second magnet; 91. Elastic snap-fit ​​block; 911. Third guide surface; 92. Snap-fit ​​protrusion; 921. Fourth guide surface; 93. Reset block; 931. Fifth guide surface. Detailed Implementation

[0039] The following is in conjunction with the appendix Figure 1-8 This application will be described in further detail.

[0040] This application discloses a reverse ball screw pair.

[0041] like Figure 1 , Figure 2 and Figure 3 The reverse ball screw assembly includes a screw 1, a nut 2, balls 3, and a return mechanism 4. The screw 1 has a cylindrical structure, and a threaded groove is provided at the connection between the screw 1 and the nut 2. This threaded groove is part of the rolling channel of the balls 3. The connection part of the screw 1 is connected to the upper-level components and is used as a push rod in actual engineering applications. Nut 2 is a cylindrical structure, sleeved on the outside of lead screw 1 and coaxially arranged with lead screw 1. Nut 2 has a threaded groove inside that matches the threaded groove of lead screw 1. Nut 2 engages with ball 3 through the threaded groove. After its own rotation, nut 2 drives the reverse lead screw 1 to perform linear motion. The threaded groove is also part of the rolling channel of ball 3. Nut 2 is connected to the upper-level drive unit. The upper-level drive unit drives nut 2 to rotate, forming an integral rotary drive component. Nut 2 has a through hole 22, which is a circular hole structure. The size of through hole 22 is adapted to the size of ball 3. A sealing cap 21 is threaded inside through hole 22, and the sealing cap 21 is adapted to through hole 22.

[0042] The lead screw 1 has an installation groove 11, which extends through both ends of the threaded groove portion of the lead screw 1 along the axial direction. The return device 4 is installed in the installation groove 11, and the bottom surface of the return device 4 matches the installation groove 11 of the lead screw 1. The bottom surface of the return device 4 is a plane that is in close contact with the plane of the return groove. The outer contour of the return device 4 is an arc-shaped structure that matches the installation groove 11. The diameter of the return device 4 is between the outer diameter of the lead screw 1 and the inner diameter of the nut 2.

[0043] like Figure 3 and Figure 4 The return device 4 has three return grooves 41, which are not interconnected and have the same structure. The three return grooves 41 are parallel to each other along the length of the return device 4 and extend through both sides of the width of the return device 4. The two ends of each return groove 41 are connected to the thread grooves of the lead screw 1 and the nut 2, respectively. Specifically, one end of the return groove 41 is connected to the thread grooves of the lead screw 1 and the nut 2, and the other end is connected to the end of the thread grooves of the lead screw 1 and the nut 2 after one revolution. The return grooves 41, together with the thread grooves of the lead screw 1 and the nut 2, form a closed ball return channel 12. The balls 3 are steel balls, and the return grooves 41 exhibit a centrally symmetrical structure.

[0044] like Figure 4 , Figure 5 and Figure 6 The inner wall of the mounting groove 11 is fixedly provided with six sets of positioning plates 13. The six sets of positioning plates 13 are located on both sides of the mounting groove 11. Three sets of positioning plates 13 are equidistantly arranged along the axial direction of the lead screw 1 on one side of the mounting groove 11. Each set of positioning plates 13 consists of two plates. The structures of the positioning plates 13 are all the same. A gap is formed between the two positioning plates 13 in each set for accommodating and limiting their position. The outer wall of the return device 4 facing the mounting groove 11 is fixedly provided with six positioning grooves 42. The positions of the positioning grooves 42 correspond to the positions of the positioning plates 13. The structure of the positioning grooves 42 is adapted to the structure of the positioning plates 13. The gap between the two positioning plates 13 is adapted to the distance between the positioning grooves 42. Each positioning plate 13 is inserted into the corresponding positioning groove 42 in the assembled state, so that the positioning groove 42 and the corresponding two positioning plates 13 together form a limiting fit structure, which provides multi-point positioning constraint for the return device 4 in the axial direction.

[0045] The snap-fit ​​assembly 5 includes a first snap-fit ​​block 51, a second snap-fit ​​block 52, a third snap-fit ​​block 53, a guide seat 112, and a first reset spring 54. The first snap-fit ​​block 51 is fixedly disposed at both ends of the return device 4 facing the mounting groove 11. The end of the first snap-fit ​​block 51 facing the mounting groove 11 is provided with a first guide surface 511. The first snap-fit ​​block 51 has a U-shaped structure. The mounting groove 11 has a receiving groove 111, the position of which corresponds to the position of the first locking block 51. The receiving groove 111 passes through the end of the return device 4. The guide seat 112 is fixedly installed at the bottom of the receiving groove 111 away from the end of the return device 4. The guide seat 112 is a cylindrical structure and extends along the axial direction of the lead screw 1. The second locking block 52 slides in the guide seat 112, which guides and restricts the second locking block 52. One end of the second locking block 52 slides in the guide seat 112, and the other end of the second locking block 52 away from the guide seat 112 is fixedly provided with a push block 55. The push block 55 is located outside the receiving groove 111 and is adapted to the port of the receiving groove 111.

[0046] A third latching block 53 is fixedly connected to the side of the second latching block 52 near the first latching block 51. The third latching block 53 and the second latching block 52 are integrally formed. The third latching block 53 has an L-shaped structure, and the third latching block 53 and the second latching block 52 form a structure that can latch the first latching block 51. A second guide surface 531 is provided on the side of the third latching block 53 facing the first latching block 51. The second guide surface 531 and the first guide surface 511 are arranged opposite to each other and form a guiding fit relationship during assembly. A first return spring 54 is sleeved on the second latching block 52. One end of the first return spring 54 is fixed to the end face of the guide seat 112 facing the third latching block 53, and the other end of the first return spring 54 abuts against the third latching block 53.

[0047] The specific installation operation of the return device 4 is as follows: When the return device 4 is inserted into the mounting slot 11 of the lead screw 1 along the installation direction, the first locking block 51 moves synchronously with the return device 4 and gradually approaches the third locking block 53. During the contact process, the first guide surface 511 and the second guide surface 531 cooperate with each other, causing the second locking block 52 to retract inward within the guide seat 112 against the elastic force of the first return spring 54, thus completing the locking of the first locking block 51 and the third locking block 53. After the return device 4 is installed in place, under the action of the first return spring 54, the second locking block 52 forms a reverse pressure on the first locking block 51, putting the locking assembly 5 in a locked state, thereby achieving a reliable fixed connection between the return device 4 and the lead screw 1. Pushing the second locking block 52 compresses the first return spring 54, causing the third locking block 53 to disengage from the first locking block 51, thereby achieving quick disassembly between the return device 4 and the lead screw 1.

[0048] like Figure 7 and Figure 8An extension cylinder 64 is fixedly installed at the end of the nut 2. The extension cylinder 64 is fixedly connected to the nut 2 by bolts. The extension cylinder 64 forms a mating cavity opposite to the connecting cylinder 62. A fixed sleeve 66 is fixedly installed inside the extension cylinder 64, extending axially along the extension cylinder 64. A second return spring 68 is fixedly installed inside the fixed sleeve 66. One end of the second return spring 68 is fixedly connected to the fixed sleeve 66, and a first stop block 65 is fixedly installed at the other end of the second return spring 68. A sliding sleeve 67 is fixedly installed on the side of the first stop block 65 facing the fixed sleeve 66. The sliding sleeve 67 is sleeved inside the fixed sleeve 66 and forms a sliding fit structure with the fixed sleeve 66. The fixed sleeve 66 forms a guide structure for the sliding sleeve 67. A first sealing ring 641 is provided at the port of the extension cylinder 64 near the first stop block 65. The first sealing ring 641 is fixedly embedded on the extension cylinder 64. In the initial state, the first stop block 65 closes the opening of the extension cylinder 64 away from the nut 2.

[0049] A fixing plate 61 is fixedly installed at the base end of the mounting screw 1 and nut 2. The fixing plate 61 serves as a support structure for the installation of components related to oil injection or coolant. A connecting cylinder 62 is fixedly installed on the side of the fixing plate 61 facing the extension cylinder 64, and the axis of the connecting cylinder 62 is coaxial with the axis of the extension cylinder 64. A blocking element 7 is slidably installed inside the connecting cylinder 62. The blocking element 7 includes a push rod 71 and a second stop 72. The push rod 71 is fixedly connected to the second stop 72, which is located on the side closer to the extension cylinder 64. A return spring 63 is fixedly installed on the end of the push rod 71 facing the fixing plate 61. One end of the return spring 63 is fixedly connected to the push rod 71, and the other end is fixedly connected to the fixing plate 61. A rod is fixedly installed on the fixing plate 61. A groove is opened on the side of the push rod 71 facing the fixing plate 61. The rod is fitted inside the return spring 63. One end of the rod is connected to the fixing plate 61, and the other end slides in the groove. A second sealing ring 621 is provided at the port of the connecting cylinder 62 near the second stop 72. The second sealing ring 621 is also embedded in the connecting cylinder 62. In the initial state, the second stop 72 closes the opening of the connecting cylinder 62 facing the extension cylinder 64.

[0050] A driving assembly 8 is provided on the connecting cylinder 62. The driving assembly 8 includes a connecting sleeve 81, a first magnet 82, and a second magnet 83. The connecting sleeve 81 is sleeved on the outside of the connecting cylinder 62 and can slide along the axial direction of the connecting cylinder 62. The connecting sleeve 81 can move from the end of the connecting cylinder 62 to the end of the extension cylinder 64. The first magnet 82 and the second magnet 83 are both annular structures. The first magnet 82 is fixedly disposed inside the connecting sleeve 81, and the second magnet 83 is fixedly disposed on the push rod 71. The first magnet 82 and the second magnet 83 are arranged opposite to each other.

[0051] An elastic snap-fit ​​block 91 is fixedly mounted on the connecting sleeve 81. The elastic snap-fit ​​block 91 is located at the end of the connecting sleeve 81 facing the nut 2. The elastic snap-fit ​​block 91 has an elastic snap-fit ​​structure, and a third guide surface 911 is provided at the end of the elastic snap-fit ​​block 91 facing the nut 2. A snap-fit ​​protrusion 92 is fixedly mounted on the extension cylinder 64. The snap-fit ​​protrusion 92 has a circular structure, and a fourth guide surface 921 is provided at the end of the snap-fit ​​protrusion 92 facing away from the nut 2. A reset block 93 is slidably mounted on the outside of the extension cylinder 64. The reset block 93 also has a circular structure and slides along the axial direction of the extension cylinder 64. The reset block 93 is located between the snap-fit ​​protrusion 92 and the nut 2, and a fifth guide surface 931 is provided on the side of the reset block 93 facing away from the snap-fit ​​protrusion 92. The structures of the reset block 93 and the snap-fit ​​protrusion 92 are symmetrical, and the outer diameter of the reset block 93 is the same as the outer diameter of the snap-fit ​​protrusion 92.

[0052] In the specific process of connecting the connecting sleeve 62 and the extension sleeve 64, when the connecting sleeve 81 is pushed to move the elastic locking block 91 axially to the locking protrusion 92, under the cooperation of the third guide surface 911 and the fourth guide surface 921, the elastic locking block 91 undergoes elastic deformation and passes over the locking protrusion 92, thereby achieving locking and fixing. At this time, the second stop block 72 enters the extension sleeve 64, and the connecting sleeve 62 and the extension sleeve 64 are connected. When the connecting sleeve 81 is pushed again to move the elastic locking block 91 axially, the elastic locking block 91 slides down to the area of ​​the fifth guide surface 931 of the reset block 93 under the guidance of the third guide surface 911. After the connecting sleeve 81 is stopped, the connecting sleeve 81 drives the reset block 93 to abut against the locking protrusion 92 under the tension of the reset spring 63, so that the elastic locking block 91 is pushed open under the action of the fifth guide surface 931, thereby releasing the locking state with the locking protrusion 92 and realizing separation and reset.

[0053] In other embodiments, the return device 4 may have two, four, five, or other numbers of return slots 41, depending on the actual load. One end of the return slot 41 is connected to the threaded grooves of the lead screw 1 and nut 2, and the other end of the return slot 41 is connected to the end of the threaded grooves of the lead screw 1 and nut 2 after rotating two or more turns. Two, four, or other numbers of positioning plates 13 may be fixedly installed on the inner wall of the mounting groove 11, and each group of positioning plates 13 may have three, four, or other numbers of positioning plates 13. Two, four, or other positioning slots 42, the same number as the groups of positioning plates 13, may be fixedly installed on the outer wall of the return device 4 facing the mounting groove 11, and each group of positioning plates 13 may also have two or three positioning slots 42.

[0054] The implementation principle of this application embodiment is as follows: During the assembly process, the return device 4 faces the mounting groove 11 so that the positioning groove 42 is inserted between the two first fixing plates 61, realizing the precise limiting and rapid positioning of the return device 4 in the axial direction, improving the assembly consistency and positional accuracy between the return device 4 and the lead screw 1. At the same time, the snap-fit ​​component 5 at the connection between the return device 4 and the lead screw 1 enables the return device 4 to be accurately positioned in the axial direction and to be reliably locked in the radial direction, enhancing the structural stability of the return device 4 during operation and preventing radial displacement under vibration, impact or long-term operating load. The positioning plate 13, the positioning groove 42 and the snap-fit ​​component 5 work together to effectively constrain the return device 4 in both the axial and radial directions, which can significantly reduce the risk of relative positional displacement between the return device 4 and the lead screw 1 and the thread groove of the nut 2, ensuring that the return groove 41 and the thread groove always maintain a good alignment relationship, thereby improving the smoothness of the ball 3 circulation, reducing rolling resistance and jamming, and improving the reliability and stability of the reverse ball screw pair operation.

[0055] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A reverse-type ball screw pair, characterized in that: The device includes a lead screw (1), a nut (2), a ball bearing (3), and a return mechanism (4). The lead screw (1) has an installation groove (11), the return mechanism (4) is located in the installation groove (11), and the return mechanism (4) has a return groove (41). The thread grooves of the lead screw (1) and the nut (2) and the return groove (41) form a return channel (12), and the ball bearing (3) is located in the return channel (12). Several sets of positioning plates (13) are fixedly arranged in the mounting groove (11), and there are two positioning plates (13) in each set. Several positioning grooves (42) are opened on the side of the return device (4) facing the mounting groove (11). The positioning plates (13) are arranged corresponding to the positioning grooves (42). The positioning plates (13) are located in the positioning grooves (42). A snap-fit ​​component (5) is provided at the connection between the return device (4) and the lead screw (1). The snap-fit ​​component (5) can fix the return device (4) on the lead screw (1).

2. The reverse-type ball screw pair according to claim 1, characterized in that: The return device (4) has a plurality of return slots (41) arranged parallel to each other along the length of the return device (4).

3. The reverse-type ball screw pair according to claim 1, characterized in that: The return groove (41) is smoothly connected to the adjacent threaded groove on the lead screw (1).

4. The reverse-type ball screw pair according to claim 1, characterized in that: The snap-fit ​​assembly (5) includes a first snap-fit ​​block (51) and a second snap-fit ​​block (52). The first snap-fit ​​block (51) is located on the side of the return device (4) facing the mounting groove (11). The end of the first snap-fit ​​block (51) facing the second snap-fit ​​block (52) is provided with a first guide surface (511). The mounting groove (11) is provided with a receiving groove (111), and a guide seat (112) is fixedly provided in the receiving groove (111). The second snap-fit ​​block (52) is slidably connected in the guide seat (112). A third snap-fit ​​block (53) is fixedly provided on the side of the second snap-fit ​​block (52) facing the first snap-fit ​​block (51). A second guide surface (531) is provided on the end of the third snap-fit ​​block (53) facing the first guide surface (511). A first reset spring (54) is sleeved on the second snap-fit ​​block (52). The first reset spring (54) is used to drive the second snap-fit ​​block (52) to reset. When the return device (4) is installed on the lead screw (1), the first snap-fit ​​block (51) and the third snap-fit ​​block (53) snap-fit ​​together.

5. The reverse-type ball screw pair according to claim 4, characterized in that: The receiving groove (111) extends through the end of the return device (4), and a push block (55) is fixedly provided at the end of the second snap block (52) away from the guide seat (112). The push block (55) can push the second snap block (52) to separate the first snap block (51) from the third snap block (53).

6. The reverse-type ball screw pair according to claim 1, characterized in that: It also includes a sealing cap (21), and the nut (2) has a through hole (22). The sealing cap (21) is threadedly connected to the through hole (22), and the ball (3) can enter the return channel (12) through the through hole (22).

7. The reverse-type ball screw pair according to claim 1, characterized in that: It also includes a fixing plate (61), on which a connecting cylinder (62) is provided, and a blocking member (7) is slidably provided inside the connecting cylinder (62). The blocking member (7) can block the end of the connecting cylinder (62) away from the fixing plate (61). A reset spring (63) is connected to the end of the blocking member (7) facing the fixing plate (61). A driving assembly (8) is provided on the connecting cylinder (62). An extension tube (64) is provided at the end of the nut (2) near the connecting tube (62). A first stop (65) is slidably provided inside the extension tube (64). The first stop (65) can block one end of the extension tube (64) facing the fixed plate (61). A fixed sleeve (66) is fixedly provided inside the extension tube (64). A sliding sleeve (67) is fixedly provided on the first stop (65). The sliding sleeve (67) is slidably connected inside the fixed sleeve (66). A second return spring (68) is provided on the first stop (65). The other end of the second return spring (68) is fixed inside the fixed sleeve (66). The drive component (8) drives the blocking component (7) to push the first stop (65), so that the connecting cylinder (62) and the extension cylinder (64) are connected.

8. The reverse-type ball screw pair according to claim 7, characterized in that: The drive assembly (8) includes a connecting sleeve (81), a first magnet (82), and a second magnet (83). The connecting sleeve (81) is sleeved outside the connecting cylinder (62) and can slide from the connecting cylinder (62) onto the extension cylinder (64). The first magnet (82) is fixedly mounted on the connecting sleeve (81). The blocking member (7) includes a push rod (71) and a second stop (72). The push rod (71) is fixedly connected to the second stop (72), and the second magnet (83) is fixedly mounted on the push rod (71). The first magnet (82) and the second magnet (83) are correspondingly arranged. When the connecting sleeve (81) is pushed, the push rod (71) moves synchronously with the connecting sleeve (81).

9. The reverse-type ball screw pair according to claim 8, characterized in that: The extension cylinder (64) is provided with a first sealing ring (641) at the port of the first stop (65), and the connecting cylinder (62) is provided with a second sealing ring (621) at the port of the second stop (72).

10. The reverse-type ball screw pair according to claim 8, characterized in that: An elastic snap-fit ​​block (91) is fixedly provided on the connecting sleeve (81), and a snap-fit ​​protrusion (92) is fixedly provided on the extension cylinder (64). A third guide surface (911) is provided on the side of the elastic snap-fit ​​block (91) facing the snap-fit ​​protrusion (92), and a fourth guide surface (921) is provided on the side of the snap-fit ​​protrusion (92) facing the elastic snap-fit ​​block (91). A reset block (93) is sleeved on the extension cylinder (64), and the reset block (93) is slidably connected to the extension cylinder (64). A fifth guide surface (931) is provided on the side of the reset block (93) away from the snap-fit ​​protrusion (92). The connecting sleeve (81) pushes the elastic locking block (91), enabling the elastic locking block (91) to engage with the locking protrusion (92). When the connecting sleeve (81) pushes the elastic locking block (91) again, the third guide surface (911) allows the elastic locking block (91) to slide onto the fifth guide surface (931). When the connecting sleeve (81) resets, it causes the reset block (93) to abut against the locking protrusion (92), causing the elastic locking block (91) to separate from the locking protrusion (92).

Images