Adjustable reverse clearance elimination mechanism for screw pair of numerical control machine tool

Abstract

The present application relates to the technical fields of machine tool feed precision transmission parts, and discloses an adjustable reverse gap elimination mechanism for a numerical control machine tool screw pair, comprising a flange, the adjustable reverse gap elimination mechanism for the numerical control machine tool screw pair drives a threaded rod to rotate through a rotating knob, converts the rotating motion into vertical displacement through a self-locking threaded block and a mounting frame, decomposes the vertical force into horizontal axial thrust, pushes a connecting plate and a secondary nut to move axially along a rectangular groove relative to a primary nut, can quickly complete the gap adjustment during the operation of the machine tool, achieves the purpose of adjusting the gap without disassembling the machine, and all the adjusting elements in the adjusting mechanism, such as the U-shaped frame body, the vertical rod, the adjusting block and the wedge-shaped block, are arranged inside and above the U-shaped box body, do not invade the fitting area between the primary nut and the secondary nut, avoid the fitting gap caused by the adjusting structure embedded in the nut, and achieve the purpose of external adjusting structure avoiding the gap in the nut.

Description

Technical Field

[0001] This invention relates to the field of precision transmission components for machine tool feed, specifically to an adjustable backlash elimination mechanism for lead screw pairs in CNC machine tools. Background Technology

[0002] Ball screw pairs are core precision transmission components in the feed transmission system of CNC machine tools. They are mainly used to convert the rotary motion of servo motors into linear feed motion of the machine tool table. Their transmission accuracy directly determines the dimensional accuracy of the workpiece and the quality of the surface machining contour. During reciprocating cutting and reversing feed processes in CNC machine tools, axial backlash inevitably occurs within the ball screw pair. This backlash can cause idle movement and misalignment during machine tool reversal, leading to machining defects such as tool marks, dimensional errors, and inaccurate positioning. Therefore, the industry commonly uses a double-nut preload structure to eliminate the backlash of the ball screw pair and ensure the feed transmission accuracy of the machine tool.

[0003] A search revealed Chinese Patent Publication No. CN201979336U, which discloses a double-nut washer-type internal circulation ball screw assembly, including a horizontally placed screw. This utility model has the advantages of simple structure, convenient assembly and disassembly, reliable operation, and good rigidity. The existing technical solutions mentioned above have the following defects: Currently, the most widely used structure on the market is the washer-type double-nut screw backlash elimination structure. This structure relies on adding a washer of fixed thickness between the two nuts to achieve pre-tightening and backlash elimination. It can only be assembled and finalized once at the product manufacturing stage, and secondary fine-tuning and compensation cannot be performed later. During the long-term operation of CNC machine tools, the balls and the screw raceway will continuously rub and wear, thus regenerating axial backlash. At this time, to restore the transmission accuracy of the screw assembly, it is necessary to completely disassemble the entire screw assembly, separate the two sets of ball nuts, and replace the washer with one of appropriate thickness. The overall disassembly and assembly process is extremely complicated, and the equipment downtime for maintenance is time-consuming, seriously delaying the normal processing and production of the machine tool and significantly reducing the overall processing capacity of the workshop. At the same time, the traditional shim-type backlash elimination structure directly installs the shim inside the gap between the two sets of ball nuts, leaving the nut mating gap in an open state. During the actual cutting process of the machine tool, metal shavings and emulsions are continuously generated. These impurities can easily penetrate into the mating end faces of the two sets of nuts through the open gap. After long-term accumulation, it will cause rust on the nut end faces and impurities to get stuck. During subsequent equipment maintenance and readjustment, the two sets of nuts are very likely to stick together and become stuck, making it impossible to separate smoothly. This further increases the difficulty of equipment maintenance, affects the overall service life of the lead screw pair and the convenience of later maintenance. Therefore, an adjustable backlash elimination mechanism for CNC machine tool lead screw pairs is proposed to solve the above-mentioned problems. Summary of the Invention

[0004] (a) Technical problems to be solved

[0005] To address the shortcomings of existing technologies, this invention provides an adjustable backlash elimination mechanism for CNC machine tool lead screw pairs. It has the advantages of allowing backlash adjustment without disassembling the machine and having an external adjustment structure to avoid gaps in the nut, thus solving the problems mentioned in the background art.

[0006] (II) Technical Solution

[0007] To achieve the aforementioned goal of adjusting the clearance without disassembling the machine and avoiding gaps in the nut due to the external adjustment structure, the present invention provides the following technical solution: an adjustable backlash elimination mechanism for CNC machine tool lead screw pairs, including a flange, a main nut fixedly installed on the right side of the flange, a nut mechanism extending to the right side of the main nut, a U-shaped box fixedly installed on the outer side of the main nut, connecting mechanisms extending to the inner side of the U-shaped box on both the front and rear sides of the nut mechanism, and an adjustment mechanism extending to the inner side of the U-shaped box and connected to the connecting mechanism on the top of the U-shaped box;

[0008] The nut mechanism includes a secondary nut located to the right of the main nut. The main nut has four rectangular slots arranged in a ring at equal intervals on its right side. The secondary nut has four rectangular plates fixedly installed on its left side, each extending into one of the four rectangular slots. An elastic sealing ring located around the rectangular plates is movably installed between the main nut and the secondary nut.

[0009] Preferably, the connecting mechanism includes a connecting plate, and connecting plates are fixedly installed on both the front and rear sides of the secondary nut. A fixing plate extending into the inner side of the U-shaped box is fixedly installed on one side of the connecting plate, and a wedge-shaped groove is provided on the top of the fixing plate.

[0010] Preferably, the adjustment mechanism includes a U-shaped frame. A U-shaped frame extending to the inner side of the top of the U-shaped box is slidably mounted thereon. Three uprights extending to the inner side of the U-shaped box are fixedly mounted on the inner top wall of the U-shaped frame. A circular plate is fixedly mounted at one bottom end of each upright. An adjusting block, slidably connected to the inner top wall of the U-shaped box, is slidably mounted on the outer side of each upright. A spring fitted onto the outer side of the upright is fixedly mounted between the adjusting block and the circular plate. Wedge-shaped blocks extending into and fitting against two wedge-shaped grooves are fixedly mounted at both the front and rear ends of the bottom of the U-shaped frame. A rectangular cavity is formed on the inner side of each wedge-shaped block. A sliding plate is mounted on the sliding plate. A telescopic spring is fixedly mounted on the right side of the sliding plate and fixedly connected to the right side of the inner wall of the rectangular cavity. A pressing block extending to the outside of the wedge block and fitting against the inside of the wedge groove is fixedly mounted on the left side of the sliding plate. A mounting bracket located above the U-shaped box is fixedly mounted between the outer sides of the three adjusting blocks. A threaded rod extending to the top of the U-shaped box is rotatably connected to the inner bottom wall of the U-shaped box. A self-locking threaded block is threadedly connected to the outer side of the threaded rod. The self-locking threaded block is fixedly connected to the left side of the mounting bracket. A vertical rod extending to the inside of the U-shaped box is fixedly mounted on the inner side of the self-locking threaded block. A knob is fixedly mounted on the top of the threaded rod.

[0011] Preferably, the inner top wall of the U-shaped box has a vertical hole that matches the U-shaped frame. The U-shaped frame can only slide vertically up and down, limiting the horizontal deviation of the U-shaped frame. The uprights are arranged vertically at equal intervals and serve as guides and limiters to ensure that the adjusting block remains horizontal during the sliding process and to prevent the adjusting block from tilting and getting stuck.

[0012] Preferably, the outer inclined surface of the wedge block and the inner inclined surface of the wedge groove have the same inclination angle, and the two inclined surfaces are in complete contact. The vertical downward compressive force can be decomposed into a horizontal axial thrust, pushing the secondary nut away from the main nut.

[0013] Preferably, the telescopic spring is arranged horizontally inside the rectangular cavity, and the telescopic spring can continuously push the moving plate to the left to provide a constant lateral clamping force to the extrusion block.

[0014] Preferably, the threaded rod is vertically rotatably installed at the center of the U-shaped box, and the self-locking threaded block uses a trapezoidal self-locking thread to cooperate with the threaded rod, which has its own mechanical self-locking performance and can automatically lock the position after rotation stops.

[0015] Preferably, the mounting bracket is horizontally fixed to the outside of the three adjusting blocks, so as to realize the synchronous linkage of the three adjusting blocks to lift and lower, and to ensure that the front and rear sets of wedge blocks are subjected to the same force.

[0016] Preferably, the rectangular plate and the rectangular groove are inserted into each other in a one-to-one correspondence, and the rectangular plate can slide axially within a small range inside the rectangular groove to meet the travel requirements of the double nut misalignment adjustment.

[0017] (III) Beneficial Effects

[0018] Compared with the prior art, the present invention provides an adjustable backlash elimination mechanism for lead screw pairs in CNC machine tools, which has the following beneficial effects:

[0019] 1. This adjustable backlash elimination mechanism for CNC machine tool lead screw pairs uses a rotary knob to rotate the threaded rod. The rotational motion is converted into vertical displacement via a self-locking threaded block and mounting bracket, causing three adjusting blocks to rise and fall synchronously. This, in turn, causes the wedge block to slide along the inclined surface of the wedge groove, decomposing the vertical force into a horizontal axial thrust. This pushes the connecting plate and the secondary nut to move axially relative to the main nut along the rectangular groove, thereby changing the relative position between the secondary nut and the main nut and achieving backlash compensation adjustment. The entire adjustment process does not require disassembling the flange and the main nut, making it convenient to operate. It can quickly complete the backlash adjustment during machine tool operation, achieving the goal of adjusting the backlash without disassembling the machine.

[0020] 2. This adjustable backlash elimination mechanism for CNC machine tool lead screw pairs features an adjustable mechanism where all adjusting elements, including the U-shaped frame, upright, adjusting block, and wedge block, are arranged inside and above the U-shaped housing. These elements do not intrude into the mating area between the main nut and the secondary nut. The secondary nut adjusts the backlash by sliding a rectangular plate within a rectangular groove. An elastic sealing ring seals the space between the rectangular plate and the groove. The adjustment is driven by an external wedge mechanism, eliminating the need for additional adjustment openings or gaps inside the nut pair. The elastic sealing ring maintains a constant seal between the main nut and the secondary nut, preventing gaps caused by the adjusting structure being embedded inside the nut. This effectively prevents chips and coolant from entering the nut pair, ensuring the transmission accuracy and service life of the lead screw pair, and achieving the goal of externally placing the adjusting structure to avoid gaps in the nut. Attached Figure Description

[0021] Figure 1 This is a three-dimensional view of the structure of the present invention;

[0022] Figure 2 This is a sectional perspective view of the nut mechanism of the present invention;

[0023] Figure 3 This is a left-side sectional perspective view of the adjustment mechanism and connecting mechanism of the present invention;

[0024] Figure 4 This is a partial left-side sectional perspective view of the connection between the upright and the circular plate of the present invention;

[0025] Figure 5 This is a partial left-side sectional perspective view of the connection between the adjusting block and the spring in this invention;

[0026] Figure 6 This is a partial left-side sectional perspective view of the connection between the adjustment mechanism and the connecting mechanism of the present invention;

[0027] Figure 7 This is a partial left-side sectional perspective view of the connection between the adjusting block and the mounting bracket of the present invention;

[0028] Figure 8 This is a partial left-side sectional perspective view of the connection between the threaded rod and the self-locking threaded block of the present invention.

[0029] In the diagram: 1. Flange; 2. Main nut; 3. Nut mechanism; 31. Secondary nut; 32. Rectangular groove; 33. Rectangular plate; 34. Elastic sealing ring; 4. U-shaped box; 5. Connecting mechanism; 51. Connecting plate; 52. Fixing plate; 53. Wedge groove; 6. Adjusting mechanism; 601. U-shaped frame; 602. Upright; 603. Circular plate; 604. Adjusting block; 605. Spring; 606. Wedge block; 607. Rectangular cavity; 608. Moving plate; 609. Telescopic spring; 610. Pressing block; 611. Mounting bracket; 612. Threaded rod; 613. Self-locking threaded block; 614. Vertical rod; 615. Knob. Detailed Implementation

[0030] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0031] Please see Figure 1-8 The present invention provides a technical solution: an adjustable backlash elimination mechanism for lead screw pairs of CNC machine tools, including a flange 1, a main nut 2 fixedly installed on the right side of the flange 1, a nut mechanism 3 extending to the right side of the main nut 2, a U-shaped box 4 fixedly installed on the outside of the main nut 2, connecting mechanisms 5 extending to the inside of the U-shaped box 4 on both the front and rear sides of the nut mechanism 3, and an adjustment mechanism 6 extending to the inside and connected to the connecting mechanism 5 on the top of the U-shaped box 4.

[0032] Flange 1 is used to fix the entire mechanism to the end of the CNC machine tool lead screw pair, providing a mounting reference and load-bearing support. The main nut 2 is fixed to the right side of flange 1 and works with the lead screw to achieve transmission. The rectangular groove 32 on its right side provides a guide groove for the axial movement of the secondary nut 31. The U-shaped box 4 is fixed to the outside of the main nut 2, providing a closed installation space and motion guidance for the connecting mechanism 5 and the adjusting mechanism 6, while also serving a protective function.

[0033] The nut mechanism 3 includes a secondary nut 31, which is located to the right of the main nut 2. The main nut 2 has four rectangular slots 32 arranged in a ring at equal intervals on its right side. The secondary nut 31 has four rectangular plates 33 fixedly installed on its left side, each extending into the inner side of one of the four rectangular slots 32. An elastic sealing ring 34 is movably installed between the main nut 2 and the secondary nut 31, located around the rectangular plate 33.

[0034] The rectangular plate 33 and the rectangular groove 32 are inserted into each other in a one-to-one correspondence. The rectangular plate 33 can slide axially within a small range inside the rectangular groove 32 to meet the travel requirements of the double nut misalignment adjustment.

[0035] The secondary nut 31 is located to the right of the main nut 2. It eliminates the backlash of the lead screw pair by interlocking with the double nuts of the main nut 2. The rectangular plate 33 on its left is inserted into the rectangular groove 32 to achieve axial sliding guidance. There are four rectangular grooves 32 arranged in a ring at equal intervals, providing an axial sliding track for the rectangular plate 33 and limiting the movement direction and stroke range of the secondary nut 31. There are four rectangular plates 33, which are inserted into the rectangular grooves 32 one by one, connecting the secondary nut 31 and the main nut 2 into one unit. At the same time, the secondary nut 31 is allowed to slide in a small range along the axial direction to complete the clearance adjustment. The elastic sealing ring 34 is movably installed between the main nut 2 and the secondary nut 31 and is located on the periphery of the rectangular plate 33. It moves synchronously with the secondary nut 31 and always seals the annular gap between the main nut 2 and the secondary nut 31 to prevent chips and coolant from entering.

[0036] The connecting mechanism 5 includes a connecting plate 51. The connecting plate 51 is fixedly installed on both the front and rear sides of the auxiliary nut 31. A fixing plate 52 extending into the inner side of the U-shaped box 4 is fixedly installed on one side of the connecting plate 51. A wedge-shaped groove 53 is provided on the top of the fixing plate 52.

[0037] The connecting plate 51 is fixed on both sides of the secondary nut 31, transmitting the axial displacement of the secondary nut 31 to the fixed plate 52. It serves as a force transmission bridge between the secondary nut 31 and the adjusting mechanism 6. The fixed plate 52 is fixed on one side of the connecting plate 51 and extends into the inner side of the U-shaped box 4. The wedge groove 53 on its top cooperates with the wedge block 606, converting the vertical movement of the adjusting mechanism 6 into a horizontal thrust. The wedge groove 53 is opened on the top of the fixed plate 52, and its inner inclined surface is completely fitted with the outer inclined surface of the wedge block 606. It is a key mating surface for realizing the direction conversion of force.

[0038] The adjustment mechanism 6 includes a U-shaped frame 601. The top of the U-shaped box 4 is slidably fitted with a U-shaped frame 601 extending into its inner side. Three uprights 602 extending into the inner side of the U-shaped box 4 are fixedly installed on the inner top wall of the U-shaped frame 601. A circular plate 603 is fixedly installed at one bottom end of each upright 602. An adjusting block 604, slidably connected to the inner top wall of the U-shaped box 4, is slidably installed on the outer side of the upright 602. A spring 605, sleeved on the outer side of the upright 602, is fixedly installed between the adjusting block 604 and the circular plate 603. Wedge-shaped blocks 606, extending into and fitting against two wedge-shaped grooves 53, are fixedly installed at both the front and rear ends of the bottom of the U-shaped frame 601. A rectangular cavity 607 is formed on the inner side of each wedge-shaped block 606. A rectangular cavity 607 is slidably installed on the inner side of the rectangular cavity 607. There is a movable plate 608. A telescopic spring 609 is fixedly installed on the right side of the movable plate 608 and is fixedly connected to the right side of the inner wall of the rectangular cavity 607. A pressing block 610 extending to the outside of the wedge block 606 and fitting against the inside of the wedge groove 53 is fixedly installed on the left side of the movable plate 608. A mounting bracket 611 located above the U-shaped box 4 is fixedly installed between the outer sides of the three adjusting blocks 604. A threaded rod 612 extending to the top of the inner bottom wall of the U-shaped box 4 is rotatably connected. A self-locking threaded block 613 is threadedly connected to the outside of the threaded rod 612. The self-locking threaded block 613 is fixedly connected to the left side of the mounting bracket 611. A vertical rod 614 extending to the inside of the U-shaped box 4 is fixedly installed on the inside of the self-locking threaded block 613. A knob 615 is fixedly installed on the top of the threaded rod 612.

[0039] The inner top wall of the U-shaped box 4 has vertical holes that fit the U-shaped frame 601. The U-shaped frame 601 can only slide vertically up and down, limiting horizontal deviation. The uprights 602 are arranged vertically at equal intervals, serving as guides and limiters to ensure that the adjusting block 604 remains horizontal during sliding, preventing it from tilting or getting stuck. The outer inclined surface of the wedge block 606 and the inner inclined surface of the wedge groove 53 have the same inclination angle, and their inclined surfaces are in complete contact. The downward pressing force can be decomposed into a horizontal axial thrust, pushing the secondary nut 31 away. Across the main nut 2, a telescopic spring 609 is horizontally arranged inside a rectangular cavity 607. The telescopic spring 609 can continuously push the moving plate 608 to the left, providing a constant lateral clamping force to the extrusion block 610. The threaded rod 612 is vertically rotatably installed at the center of the U-shaped box 4. The self-locking threaded block 613 uses a trapezoidal self-locking thread to cooperate with the threaded rod 612, and has its own mechanical self-locking performance. After stopping rotation, it can automatically lock its position. The mounting bracket 611 is horizontally fixed on the outside of the three adjusting blocks 604, realizing the synchronous linkage lifting and lowering of the three adjusting blocks 604, ensuring that the front and rear sets of wedge blocks 606 are subjected to the same force.

[0040] The U-shaped frame 601 is slidably installed in the vertical hole at the top of the U-shaped box 4, and can only slide vertically up and down. It supports the wedge block 606 and transmits the vertical displacement of the adjusting block 604 to the wedge block 606. Three vertical uprights 602 are fixed at equal intervals to the inner top wall of the U-shaped frame 601 and extend to the inner side of the U-shaped box 4, providing vertical guidance for the adjusting block 604 and ensuring that the adjusting block 604 remains horizontal during the lifting and lowering process, preventing tilting and jamming. The circular plate 603 is fixed to the bottom of the upright 602, serving as the lower support point of the spring 605 and limiting the compression stroke of the spring 605. The adjusting block 604 is slidably installed on the outside of the upright 602 and slidably connected to the inner top wall of the U-shaped box 4, and slides up and down along the upright 602 under the action of the spring 605. The movement causes the U-shaped frame 601 and the wedge block 606 to rise and fall synchronously. The spring 605 is sleeved on the outside of the upright 602, with one end connected to the adjusting block 604 and the other end connected to the circular plate 603, providing a reset preload for the adjusting block 604, so that the wedge block 606 always fits downward against the wedge groove 53. The wedge block 606 is fixed at the front and rear ends of the bottom of the U-shaped frame 601 and extends to the inside of the wedge groove 53. Its outer inclined surface fits against the inner inclined surface of the wedge groove 53, decomposing the vertical displacement of the U-shaped frame 601 into a horizontal axial thrust that pushes the fixed plate 52. The rectangular cavity 607 is opened inside the wedge block 606, providing installation space for the moving plate 608 and the telescopic spring 609. The moving plate 608 is slidably installed inside the rectangular cavity 607. Pushed by 9, the compression block 610 slides left and right, keeping it tightly against the inner side of the wedge groove 53. The telescopic spring 609 is arranged laterally inside the rectangular cavity 607, with its right end fixed to the right side of the inner wall of the rectangular cavity 607 and its left end pushing against the moving plate 608, continuously providing a constant lateral pressing force to the compression block 610, eliminating the gap between the wedge surfaces. The compression block 610 is fixed to the left side of the moving plate 608 and extends to the outside of the wedge block 606. Under the pushing of the telescopic spring 609, it always keeps in contact with the inner inclined surface of the wedge groove 53, ensuring effective force transmission without backlash. The mounting bracket 611 is laterally fixed to the outside of the three adjusting blocks 604, connecting the three adjusting blocks 604 into one unit to achieve synchronous linkage lifting, ensuring that the front and rear sets of wedge blocks 606 are subjected to the same force, avoiding... The secondary nut 31 is tilted, and the threaded rod 612 is vertically rotated and installed at the center of the U-shaped box 4. It transmits the motion to the self-locking threaded block 613 through rotation, which is the power input element of the entire adjustment mechanism. The self-locking threaded block 613 is threaded to the outside of the threaded rod 612 and adopts a trapezoidal self-locking thread fit. It converts the rotational motion of the threaded rod 612 into its own vertical lifting motion. After the rotation stops, it automatically locks in position. The vertical rod 614 is fixed to the inside of the self-locking threaded block 613 and extends to the inside of the U-shaped box 4 to enhance the lifting stability of the self-locking threaded block 613 and prevent it from rotating with the threaded rod 612. The knob 615 is fixed to the top of the threaded rod 612 and is rotated by the operator to drive the entire adjustment mechanism. It is the direct execution entry point for adjustment operation.

[0041] During use and adjustment, rotating knob 615 drives threaded rod 612 to rotate. The trapezoidal self-locking thread between threaded rod 612 and self-locking threaded block 613 converts the rotational motion into the vertical lifting motion of self-locking threaded block 613. Self-locking threaded block 613 is fixedly connected to mounting bracket 611 via vertical rod 614. Mounting bracket 611 simultaneously drives three adjusting blocks 604 to rise and fall synchronously along vertical rod 602. Vertical rod 602 acts as a guide and limiter, ensuring that adjusting blocks 604 always remain horizontal and preventing tilting and jamming. Adjusting blocks 604 are provided with reset preload by spring 605, driving U-shaped frame 601 and bottom wedge block 606 to move synchronously. The outer inclined surface of wedge block 606 is completely in contact with the inner inclined surface of wedge groove 53 on fixed plate 52. Vertical displacement is achieved through the inclined surface. This force is converted into a horizontal axial thrust, pushing the fixed plate 52 and the connecting plate 51 to move to the right. This, in turn, causes the secondary nut 31 to move axially relative to the main nut 2 along the rectangular groove 32. The rectangular plate 33 on the left side of the secondary nut 31 slides in the rectangular groove 32. The elastic sealing ring 34 moves synchronously with the secondary nut 31 and maintains the seal between the main nut 2 and the secondary nut 31. At the same time, the squeezing block 610 in the wedge block 606 is always in contact with the inner side of the wedge groove 53 under the continuous pushing of the telescopic spring 609, eliminating the gap between the wedge surfaces and ensuring the effective transmission of force. When the reverse gap is eliminated, stop rotating the knob 615. The trapezoidal self-locking thread automatically locks, and the positions of the adjusting block 604 and the secondary nut 31 are fixed without additional locking operation. If reverse adjustment is required, simply rotate the knob 615 in the opposite direction.

[0042] Furthermore, any content not described in detail in this specification is existing technology known to those skilled in the art.

[0043] In summary, this adjustable backlash elimination mechanism for CNC machine tool lead screw pairs is fixedly installed at the end of the CNC machine tool lead screw pair via flange 1. The main nut 2 and the auxiliary nut 31 form a double nut structure. The auxiliary nut 31 is engaged with the rectangular slots 32 on the main nut 2 via four sets of rectangular plates 33 to achieve axial misalignment adjustment. The elastic sealing ring 34 ensures the sealing between the nut pairs. The adjustment process is entirely completed by the external adjustment mechanism 6. The rotating knob 615 transmits force through multiple stages via threaded rod 612, self-locking threaded block 613, mounting bracket 611, adjusting block 604, spring 605, U-shaped frame 601, wedge block 606, and pressing block 610 to adjust the knob. The rotational motion is ultimately converted into the axial displacement of the secondary nut 31 relative to the main nut 2. The inclined surface of the wedge-shaped surface realizes the conversion of the force direction. The telescopic spring 609 ensures that the pressing block 610 and the wedge groove 53 fit together without gap. The three sets of uprights 602 and the mounting bracket 611 ensure that the front and rear forces are consistent. The trapezoidal self-locking thread realizes automatic locking after adjustment. The entire adjustment process does not require disassembling the flange 1 and the main nut 2. All adjustment elements are arranged outside the U-shaped box 4 and do not intrude into the nut pair mating area. The back clearance can be accurately eliminated and locked without disassembling the machine. At the same time, it avoids the nut gap problem caused by the embedded adjustment structure. It is suitable for online rapid back clearance adjustment of CNC machine tool lead screw pairs.

[0044] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0045] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. An adjustable backlash elimination mechanism for lead screw pairs in CNC machine tools, comprising a flange (1), wherein a main nut (2) is fixedly installed on the right side of the flange (1), characterized in that: The main nut (2) is provided with a nut mechanism (3) extending to its right side. A U-shaped box (4) is fixedly installed on the outside of the main nut (2). Both the front and rear sides of the nut mechanism (3) are provided with connecting mechanisms (5) extending to the inside of the U-shaped box (4). The top of the U-shaped box (4) is provided with an adjustment mechanism (6) extending to its inside and connected to the connecting mechanism (5). The nut mechanism (3) includes a secondary nut (31), which is located on the right side of the main nut (2). The main nut (2) has four rectangular slots (32) arranged in a ring at equal intervals on its right side. The secondary nut (31) has four rectangular plates (33) fixedly installed on its left side, each extending into the inner side of one of the four rectangular slots (32). An elastic sealing ring (34) located around the rectangular plate (33) is movably installed between the main nut (2) and the secondary nut (31).

2. The adjustable backlash elimination mechanism for CNC machine tool lead screw pairs according to claim 1, characterized in that: The connecting mechanism (5) includes a connecting plate (51). The connecting plate (51) is fixedly installed on both the front and rear sides of the secondary nut (31). A fixing plate (52) extending to the inside of the U-shaped box (4) is fixedly installed on one side of the connecting plate (51). A wedge-shaped groove (53) is provided on the top of the fixing plate (52).

3. The adjustable backlash elimination mechanism for CNC machine tool lead screw pairs according to claim 1, characterized in that: The adjustment mechanism (6) includes a U-shaped frame (601). The top of the U-shaped box (4) is slidably fitted with a U-shaped frame (601) extending to its inner side. The inner top wall of the U-shaped frame (601) is fixedly fitted with three uprights (602) extending to the inner side of the U-shaped box (4). A circular plate (603) is fixedly fitted at one bottom end of the uprights (602). The outer side of the uprights (602) is slidably fitted with an inner top plate of the U-shaped box (4). An adjusting block (604) is slidably connected to the wall. A spring (605) fitted on the outside of the upright (602) is fixedly installed between the adjusting block (604) and the circular plate (603). Wedge blocks (606) extending into and fitting with the two wedge grooves (53) are fixedly installed at both the front and rear ends of the bottom of the U-shaped frame (601). A rectangular cavity (607) is opened on the inner side of the wedge block (606). The inner side of the rectangular cavity (607) is slidably connected. A movable plate (608) is provided, and a telescopic spring (609) fixedly connected to the right side of the inner wall of the rectangular cavity (607) is fixedly installed on the right side of the movable plate (608). A pressing block (610) extending to the outside of the wedge block (606) and fitting against the inside of the wedge groove (53) is fixedly installed on the left side of the movable plate (608). A mounting bracket (611) located above the U-shaped box (4) is fixedly installed between the outer sides of the three adjusting blocks (604). The inner bottom wall of the U-shaped box (4) is rotatably connected to a threaded rod (612) extending to its top. The outer side of the threaded rod (612) is threadedly connected to a self-locking threaded block (613). The self-locking threaded block (613) is fixedly connected to the left side of the mounting bracket (611). The inner side of the self-locking threaded block (613) is fixedly installed with a vertical rod (614) extending to the inner side of the U-shaped box (4). The top of the threaded rod (612) is fixedly installed with a knob (615).

4. The adjustable backlash elimination mechanism for CNC machine tool lead screw pairs according to claim 3, characterized in that: The inner top wall of the U-shaped box (4) is provided with vertical holes that are compatible with the U-shaped frame (601). The U-shaped frame (601) can only slide vertically up and down, which restricts the U-shaped frame (601) from shifting horizontally. The uprights (602) are arranged vertically at equal intervals. The uprights (602) play a guiding and limiting role, ensuring that the adjusting block (604) remains horizontal during the sliding process and preventing the adjusting block (604) from tilting and getting stuck.

5. The adjustable backlash elimination mechanism for CNC machine tool lead screw pairs according to claim 3, characterized in that: The outer inclined surface of the wedge block (606) and the inner inclined surface of the wedge groove (53) are at the same angle. The two inclined surfaces are in complete contact. The vertical downward squeezing force can be decomposed into a horizontal axial thrust, which pushes the secondary nut (31) away from the main nut (2).

6. The adjustable backlash elimination mechanism for CNC machine tool lead screw pairs according to claim 3, characterized in that: The telescopic spring (609) is arranged horizontally inside the rectangular cavity (607). The telescopic spring (609) can continuously push the moving plate (608) to the left, providing a constant lateral clamping force to the extrusion block (610).

7. The adjustable backlash elimination mechanism for CNC machine tool lead screw pairs according to claim 3, characterized in that: The threaded rod (612) is vertically rotated and installed at the center of the U-shaped box (4). The self-locking threaded block (613) is fitted with the threaded rod (612) using a trapezoidal self-locking thread, and has its own mechanical self-locking performance. It can automatically lock its position after the rotation stops.

8. The adjustable backlash elimination mechanism for CNC machine tool lead screw pairs according to claim 3, characterized in that: The mounting bracket (611) is horizontally fixed on the outside of the three adjusting blocks (604) to achieve synchronous linkage lifting of the three adjusting blocks (604) and ensure that the front and rear sets of wedge blocks (606) are subjected to the same force.

9. The adjustable backlash elimination mechanism for CNC machine tool lead screw pairs according to claim 1, characterized in that: The rectangular plate (33) and the rectangular groove (32) are connected in a one-to-one manner. The rectangular plate (33) can slide axially within a small range inside the rectangular groove (32) to meet the travel requirements of the double nut misalignment adjustment.

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