A device for manufacturing a ball screw nut and a ball screw nut

Abstract

The utility model discloses a preparation device and ball screw nut of ball screw nut, wherein preparation device includes: upper die subassembly, upper die subassembly includes upper die plate and movable plate, is equipped with a plurality of sliders that distribute along circumference on movable plate, and the bottom fixed mounting of upper die plate has core rod, the outer surface of slider has the forming convex for forming circulating ball channel, and the forming convex of a plurality of sliders arranges along spiral direction, lower die subassembly includes lower die plate, and the recess for placing nut embryo material has on lower die plate, in the moulding process, slider inserts into nut embryo material, and core rod inserts the gap between slider and drives slider and moves along radial outward, and makes the forming convex on the surface of slider form circulating ball channel in embryo material inner wall. The utility model provides a preparation device of ball screw nut to realize in one forming process can high -efficient, accurate in the nut inner wall form a plurality of circulating ball channels that arrange along spiral direction to improve processing accuracy and production efficiency significantly.

Description

Technical Field

[0001] This utility model relates to the field of ball screw nut technology, and more specifically, to a ball screw nut preparation device and a ball screw nut. Background Technology

[0002] A ball screw assembly is a precision transmission mechanism that converts rotary motion into linear motion. It typically consists of a screw, a nut, balls, and a reversing mechanism. A helical raceway is formed between the screw and the nut, and the balls circulate between them to achieve efficient transmission and precise positioning.

[0003] In existing lead screw nut manufacturing processes, plastic forming or machining is often used to create circulating ball channels on the inner wall of the nut. For example, US Patent 7107805B2 discloses a method for manufacturing a lead screw nut for a spherical thread transmission mechanism, which involves performing multiple plastic forming processes on the inner circumferential surface of the nut blank to form a concave structure for ball circulation. Each processing step can only form one concave space; to obtain multiple circulation channels spaced apart along the helical direction, the forming process must be repeated multiple times.

[0004] However, the existing processing methods described above have significant shortcomings. Since only one cyclic recess can be formed at a time, the entire processing requires multiple repetitions of the forming operation, which not only increases the manufacturing cycle and equipment load but also easily leads to the accumulation of dimensional deviations between the recesses, affecting the consistency of the cyclic ball track's precision. Furthermore, multiple plastic processing operations exacerbate the concentration of internal stress in the blank, reducing the structural stability and service life of the nut. Utility Model Content

[0005] The purpose of this invention is to provide a manufacturing device for ball screw nuts, which can efficiently and accurately form multiple circulating ball tracks arranged in a spiral direction on the inner wall of the nut in a single forming process, thereby significantly improving processing accuracy and production efficiency.

[0006] The technical solution adopted by this utility model is: to provide a preparation device for ball screw nuts, which includes an upper mold assembly and a lower mold assembly.

[0007] The upper mold assembly includes an upper template and a movable plate. The movable plate is positioned below the upper template and can move up and down relative to it. The movable plate has multiple sliders distributed circumferentially, and a core rod is fixedly installed at the bottom of the upper template. The outer surface of the sliders has forming protrusions for forming the circulating ball track, and the forming protrusions of the multiple sliders are arranged in a spiral direction.

[0008] The lower mold assembly includes a lower template with a groove for placing the nut blank.

[0009] During the mold closing process, the slider is inserted into the nut blank, the movable plate first abuts against the lower template, and then the upper template continues to move downward. The core rod is inserted into the gap between the sliders and drives the sliders to move radially outward, so that the forming protrusions on the surface of the slider form a circulating ball track distributed in a spiral direction on the inner wall of the blank.

[0010] Compared with the prior art, the present invention has the following significant advantages and beneficial effects: 1. By setting multiple sliders distributed along the circumference, and driving the sliders to expand synchronously during the mold closing process, the synchronous plastic forming of multiple circulating ball channels on the inner wall of the nut is achieved, avoiding the complex process of repeated processing in the traditional method.

[0011] 2. Since all the circulating ball channels are formed in the same molding process, the spacing and shape between each channel are highly consistent, which fundamentally solves the problem of dimensional deviation accumulation caused by multiple processing and ensures smooth ball circulation.

[0012] 3. Single-stage forming reduces the superposition of internal stress caused by multiple plastic deformations, significantly improving the structural stability and service life of the nut.

[0013] 4. The movable plate and the core rod work together to realize the automatic radial movement of the slider, which can be integrated with injection molding or forging forming processes to achieve efficient mass production.

[0014] According to one embodiment of this utility model, the slider has a main body extending axially, a guide block arranged radially at the first end of the main body, and a guide groove on the movable plate that slides with the guide block. This design ensures that the slider maintains precise guidance during radial movement, avoiding wobbling or tilting, thereby improving forming accuracy and mold stability. The preparation device is the mold.

[0015] According to one embodiment of this utility model, the movable plate is provided with a plurality of reset cylinders arranged circumferentially, each reset cylinder corresponding to a slider. The moving end of the reset cylinder abuts against the slider to drive the first end of the slider to move radially inward; that is, the moving end of the reset cylinder abuts against the guide block to drive the guide block to move radially inward. This structure enables automatic reset of the slider after forming, simplifies the demolding process, and improves the efficiency of cyclic production.

[0016] According to one embodiment of this utility model, the second end of the slider has a conical surface, and the conical surfaces of multiple sliders together form a conical surface; the lower mold assembly also includes a reset bushing, which pushes the second end of the slider radially inward when the mold is opened. Through the mechanical pushing action of the reset bushing, the slider can be reliably reset, preventing jamming and extending the service life of the mold.

[0017] According to one embodiment of the present invention, the reset bushing has a tapered guide surface that mates with the conical surface; when the mold is closed, the reset bushing moves toward the slider, and the tapered guide surface abuts against the conical surface to drive the slider to move radially inward.

[0018] According to one embodiment of this utility model, the lower mold assembly includes a transmission rod and a push rod. One end of the transmission rod is fixedly connected to the reset bushing, and the push rod pushes the other end of the transmission rod to drive the reset bushing to move towards the slider. The movement of the reset bushing is achieved through mechanical transmission, ensuring synchronized action and reliable force transmission.

[0019] According to one embodiment of this utility model, a limiting ring is fixedly installed on the lower template. When the mold is closed, the outer surface of the slider abuts against the inner diameter of the limiting ring to form a limit. The limiting ring can effectively control the maximum outward expansion position of the slider, preventing over-rushing that could damage the nut blank or cause mold wear.

[0020] According to one embodiment of the present invention, the upper template and the movable plate are connected by a nitrogen spring or an overpressure relief cylinder.

[0021] According to one embodiment of this utility model, the core rod is frustum-shaped, with its outer surface serving as the pressure-applying surface and the inner surface of the slider serving as the pressure-receiving surface. The sliding contact between the pressure-applying surface and the pressure-receiving surface converts the axial movement of the core rod into the radial movement of the slider. The frustum-shaped core rod design facilitates the uniform distribution of axial thrust, enabling synchronous outward expansion of the slider. The structure is simple and the force transmission is stable.

[0022] According to one embodiment of this utility model, the ball screw nut is prepared by the above-described device. The nut prepared using the device of this utility model has high consistency in the inner wall circulation track and good surface precision, which can significantly improve the transmission efficiency and service life of the ball screw pair. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 This is a perspective view of the preparation apparatus in an embodiment of this utility model.

[0025] Figure 2 This is a top view of the preparation apparatus in an embodiment of this utility model.

[0026] Figure 3 This is a cross-sectional view of the preparation device in the embodiment of this utility model during mold closing.

[0027] Figure 4 This is a cross-sectional view of the preparation device in the embodiment of this utility model when the mold is opened.

[0028] Figure 5 This is a half-sectional perspective view of the upper mold assembly in an embodiment of this utility model.

[0029] Figure 6 This is a perspective view of multiple sliders in an embodiment of this utility model.

[0030] Figure 7 This is a schematic diagram of the structure of the movable plate, slider, and reset cylinder in the embodiment of this utility model.

[0031] Figure 8 This is a schematic diagram of the structure of the movable plate in an embodiment of this utility model.

[0032] Figure 9 This is a half-sectional perspective view of the lower mold assembly in an embodiment of this utility model.

[0033] Figure 10 This is a perspective view of the core rod and slider in an embodiment of this utility model.

[0034] Figure 11 This is a schematic diagram of the structure of the reset bushing, transmission rod, and push rod in the embodiment of this utility model.

[0035] Figure 12 This is a half-sectional perspective view of the reset bushing in an embodiment of this utility model.

[0036] Explanation of the labels in the diagram: 10. Upper mold assembly; 20. Lower mold assembly; 30. Blank; 11. Upper template; 12. Nitrogen spring; 13. Movable plate; 14. Slider; 15. Positioning ring; 16. Core rod; 17. Reset cylinder; 13a. Mounting groove; 13b. Guide groove; 13c. Side mounting hole; 13d. Center hole; 13e. Boss; 14a. Main body; 14b. Guide block; 14c. Molding protrusion; 14d. Conical surface; 14e. Pressure-bearing surface; 16a. Pressure application surface; 21. Lower template; 22. Reset bushing; 23. Transmission rod; 24. Limiting ring; 25. Top rod; 21a. Groove; 22a. Conical guide surface; 24a. Stepped surface. Detailed Implementation

[0037] The embodiments of this utility model are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this utility model, and should not be construed as limiting this utility model.

[0038] like Figure 1-12 As shown, a ball screw nut preparation apparatus includes an upper mold assembly 10 and a lower mold assembly 20.

[0039] The upper mold assembly 10 includes an upper mold plate 11 and a movable plate 13. The movable plate 13 is located below the upper mold plate 11 and can move up and down relative to it. The movable plate 13 is provided with a plurality of sliders 14 distributed along the circumference. A core rod 16 is fixedly installed at the bottom of the upper mold plate 11. The outer surface of the sliders 14 has forming protrusions 14c for forming the circulating ball track, and the forming protrusions 14c on the plurality of sliders 14 are arranged at intervals along the spiral direction.

[0040] The lower mold assembly 20 includes a lower template 21, which has a groove 21a for placing the nut blank 30.

[0041] During the mold closing process, the slider 14 is inserted into the nut blank 30. The movable plate 13 first abuts against the lower template 21, and then the upper template 11 continues to move downward. The core rod 16 is inserted into the gap between the sliders 14 and drives the sliders 14 to move outward in the radial direction, so that the forming protrusions 14c on the surface of the slider 14 form a circulating ball channel distributed in the spiral direction on the inner wall of the blank 30.

[0042] Combination Figure 6 As shown, since the slider 14 needs to be fully inserted into the nut blank 30, multiple circulating channels are formed on the nut using the forming protrusion 14c in the middle surface area of ​​the slider 14, and the circulating channels are arranged at intervals along the spiral on the inner surface of the nut. Therefore, the length of the slider 14 is greater than the axial length of the nut blank 30, which causes the slider 14 to easily adhere to the inner surface of the nut blank 30 after cold heading, making it difficult for the slider 14 to return to its original position when the core rod 16 is pulled out directly. If only a spring force is applied to one end of the slider 14 in the axial direction for return, the forces on both ends of the slider 14 in the axial direction will be uneven, which will easily cause axial displacement. Since the cross-section of the circulating channel is S-shaped, if the slider 14 causes axial displacement, the forming protrusion 14c is easy to get stuck in the formed circulating channel, causing jamming.

[0043] Therefore, in combination Figure 2-3 As shown, in this embodiment, a reset structure is provided at both ends of the slider 14, namely the first end and the second end of the slider 14, so that the two reset structures work simultaneously, causing the two ends of the slider 14 to move radially with uniform force, thereby achieving a smooth reset.

[0044] Specifically, in combination Figure 6As shown, the slider 14 has a main body 14a extending axially. The first end of the main body 14a is provided with a guide block 14b arranged radially. The movable plate 13 has a guide groove 13b that slides with the guide block 14b. The movable plate 13 is provided with a plurality of reset cylinders 17 arranged circumferentially. Each reset cylinder 17 corresponds to the slider 14, and its moving end abuts against the slider 14 to drive the first end of the slider 14 to move radially inward.

[0045] Combination Figure 8 As shown, the movable plate 13 is disc-shaped, with a circular mounting groove 13a on its upper surface. Multiple guide grooves 13b are radially distributed at the bottom of the mounting groove 13a. A central hole 13d is located at the center of the bottom of the mounting groove 13a. The main body 14a of the slider 14 passes through this central hole 13d and extends below the movable plate 13. The guide block 14b on the slider 14 has a sliding fit with the guide groove 13b, constraining the radial movement of the slider 14 by the guide groove 13b. The multiple guide grooves 13b are evenly distributed with the center of the central hole 13d as the center. Multiple lateral mounting holes 13c are radially penetrating the outer circumference of the movable plate 13. A reset cylinder 17 is installed in each lateral mounting hole 13c. The moving end of the reset cylinder 17, i.e., the piston rod, passes through the inner wall of the lateral mounting hole 13c and abuts tightly against the outer wall of the guide block 14b, thereby pushing the guide block 14b radially inward when the reset cylinder 17 extends. By synchronously operating multiple reset cylinders 17, multiple sliders 14 can be simultaneously reset radially inward.

[0046] Combination Figure 7 As shown, a positioning ring 15 is fixedly installed on the movable plate 13. The positioning ring 15 cooperates with the mounting groove 13a, and the upper end of the guide block 14b forms a sliding contact with the lower surface of the positioning ring 15. The positioning ring 15 and the guide groove 13b together define the radial sliding channel of the slider 14 to ensure the stability and accuracy of the slider 14's movement.

[0047] Furthermore, combined Figure 2-3 As shown, the second end of the slider 14 has a conical surface 14d, and the conical surfaces 14d of multiple sliders 14 together form a conical surface 14d. The lower mold assembly 20 also includes a reset bushing 22, which is disposed in the groove 21a of the lower mold plate 21. When the mold is opened, the reset bushing 22 pushes the second end of the slider 14 upward, causing the slider 14 to move radially inward, thereby achieving synchronous reset of the lower end of the slider 14. This structure prevents the slider 14 from getting stuck in the nut blank 30 after molding, which is beneficial for smooth demolding.

[0048] Furthermore, combining Figure 11-12As shown, the reset bushing 22 has a tapered guide surface 22a that mates with the conical surface 14d. During mold closing, the reset bushing 22 moves towards the slider 14, and the tapered guide surface 22a abuts against the conical surface 14d of the slider 14, driving the slider 14 to move radially inward. Through this tapered mating structure, the reset bushing 22 can play a pre-positioning role when the mold closes, keeping the slider 14 in a controlled state during radial movement, thereby ensuring the accuracy of the synchronous outward expansion of the slider 14.

[0049] Furthermore, combined Figure 11 As shown, the lower mold assembly 20 includes a transmission rod 23 and a push rod 25. One end of the transmission rod 23 is fixedly connected to the reset bushing 22, and the push rod 25 pushes the other end of the transmission rod 23 to drive the reset bushing 22 to move towards the slider 14. Through the push of the push rod 25, the transmission rod 23 transmits axial movement to the reset bushing 22, realizing the synchronous movement of the reset bushing 22 during mold closing and opening.

[0050] Combination Figure 7 As shown, a limiting ring 24 is fixedly installed on the lower template 21. When the mold is closed, the outer surface of the slider 14 abuts against the inner diameter of the limiting ring 24 to form a limit. The limiting ring 24 can effectively control the maximum outward expansion position of the slider 14, preventing the slider 14 from moving outward too much, which would cause excessive deformation of the inner wall of the nut blank 30 or wear of the mold components.

[0051] Furthermore, a limiting ring 24 is installed on the lower template 21. The inner diameter of the limiting ring 24 is smaller than the inner hole of the groove 21a. The inner hole of the groove 21a matches the outer diameter of the nut blank 30, allowing the blank 30 to be inserted and easily removed. When the circulating ball track is upset, the outer wall of the nut blank 30 is in close contact with the inner wall of the groove 21a to bear the radial forming force. Figure 9 As shown, the limiting ring 24 and the groove 21a together form the stepped surface 24a structure. The first function of the limiting ring 24 is to physically limit the radial outward movement of the slider 14, and the second function is to support the nut blank 30. The bottom of the blank 30 rests on the stepped surface 24a. When the mold is closed, the boss 13e at the bottom of the movable plate 13 abuts against the upper end of the blank 30 to form an axial limit. The boss 13e and the stepped surface 24a provide bidirectional support for the upper and lower ends of the blank 30, preventing axial displacement of the blank 30 during the forming process. The outer diameter of the boss 13e at the bottom of the movable plate 13 is smaller than the inner diameter of the nut blank 30 to ensure the insertion space of the boss 13e within the blank 30.

[0052] Furthermore, combined Figure 5As shown, a nitrogen spring 12 is fixedly installed on the upper mold plate 11, and the piston rod end of the nitrogen spring 12 is fixedly connected to the movable plate 13. During the mold closing process, when the upper mold plate 11 moves towards the lower mold plate 21, the movable plate 13 first abuts against the lower mold assembly 20. Then, the upper mold plate 11 continues to move downward, and the piston rod of the nitrogen spring 12 is gradually compressed. The internal pressure of the nitrogen spring 12 continues to increase until it reaches its maximum compression state. At this time, the core rod 16 continues to be inserted downward, driving the five sliders 14 to move outward synchronously in the radial direction. The forming protrusions 14c on the outer surface of the sliders 14 press against the inner wall of the nut blank 30 to form a circulating ball track.

[0053] During this process, because the upper and lower ends of the nut blank 30 are sealed by the movable plate 13 and the limiting ring 24 respectively, the blank 30 is in a completely sealed state, and the material cannot flow axially. This causes stress concentration in the forming protrusion 14c area of ​​the slider 14 during cold heading, resulting in concentrated stress on the mold and significantly reducing the mold's service life. If the upper or lower end of the blank 30 is not sealed to avoid stress concentration, the material of the blank 30 can flow along both ends. Although this can reduce the mold load, it will lead to insufficient filling of the circulating ball channel and incomplete forming, requiring subsequent machining correction, which affects forming efficiency and accuracy.

[0054] To simultaneously ensure the full filling of the circulating ball channel and extend the mold's service life, this invention proposes an improved solution using an overpressure relief cylinder instead of the nitrogen spring 12. This overpressure relief cylinder is fixedly installed on the upper template 11, with its piston rod end fixedly connected to the movable plate 13. When the movable plate 13 and the limiting ring 24 jointly seal both ends of the nut blank 30, the flow pressure of the blank 30 material during the forming process is transmitted to the piston rod of the overpressure relief cylinder through the movable plate 13. When this pressure exceeds the cylinder's set threshold, the piston rod will move slightly upwards, thereby creating a limited relief space for the movable plate 13, forming a buffer zone for temporary material flow. The distance the piston rod moves slightly upwards depends on the flow rate of the blank 30 material, assuming the circulating ball channel is fully filled. This structure provides adequate filling space for the blank 30, ensuring full forming of the circulating ball channel, while effectively dispersing impact stress and significantly extending the mold's lifespan.

[0055] Furthermore, the specific solutions that can be adopted for the overpressure relief cylinder include: 1. An adjustable preload spring structure is set at the tail of the cylinder. By adjusting the spring preload, the retraction threshold is limited. When the forming pressure exceeds the threshold, the cylinder as a whole generates a short stroke retraction, realizing simple pressure limiting protection. The structure is compact and easy to maintain.

[0056] 2. The cylinder is equipped with a gas-liquid partition. The gas chamber is pre-filled with nitrogen, and the liquid chamber is connected to the overflow valve and accumulator. When the forming pressure is too high, the hydraulic oil flows through the overflow valve to achieve flexible retreat, and the gas rebounds and resets, which can provide a smooth retreat and buffering effect, suitable for high-precision forming.

[0057] Third, by combining a proportional valve and a force sensor, real-time detection and electronic control can be achieved. When the pressure reaches the set value, the proportional valve automatically releases pressure, causing the piston rod to retract along a preset curve. The retraction amount and speed can be programmably adjusted, enabling precise control of the filling process while also protecting the mold.

[0058] Fourth, a throttle orifice and a one-way valve are set in the cylinder circuit. When the pressure exceeds the threshold during forming, the gas is slowly released through the throttle orifice, causing the piston rod to retract in a controllable manner. During reset, the piston rod quickly returns to its original position through the one-way valve. This structure is low in cost, has a stable response, and is easy to adjust.

[0059] Furthermore, combined Figure 10 As shown, the core rod 16 is frustum-shaped, with its outer surface being the pressure surface 16a and the inner surface of the slider 14 being the pressure-receiving surface 14e. The pressure surface 16a and the pressure-receiving surface 14e maintain sliding contact. When the core rod 16 moves axially, the axial thrust is converted into radial thrust by the contact between the pressure surface 16a and the inclined surface of the inner surface of the slider 14, thereby achieving the synchronous outward expansion of the slider 14. The multi-faceted design of the frustum-shaped core rod 16 can evenly distribute the force on each slider 14, making the slider 14 move stably and with uniform force, further improving the symmetry and accuracy of the forming process.

[0060] Furthermore, in another embodiment, a ball screw nut is disclosed, which is prepared by the above-described apparatus. By using this preparation apparatus for forming, multiple circulating ball tracks arranged in the helical direction can be formed simultaneously during a single mold closing process. The resulting ball screw nut exhibits high consistency and excellent precision in its inner wall circulating ball tracks, significantly improving the product's transmission performance and service life.

[0061] In the ball screw nut preparation device of this utility model, the working process includes two main stages: mold closing and forming, and mold opening and resetting.

[0062] Combination Figure 2As shown, during the mold closing stage, the lower mold assembly 20 holds the nut blank 30 in place. The movable plate 13 moves downward under the drive of the upper mold plate 11, and multiple sliders 14 descend synchronously with the movable plate 13. When the movable plate 13 first contacts the lower mold plate 21, the upper mold plate 11 continues to press downward, and the core rod 16 fixed at its bottom inserts into the central area between the multiple sliders 14. As the core rod 16 gradually penetrates deeper, its frustum-shaped outer surface interacts with the inner pressure surface 14e of the slider 14, generating a radial component force, causing each slider 14 to expand radially outward. During this process, the forming protrusions 14c on the outer surface of the slider 14 are pressed into the inner wall of the nut blank 30, gradually forming a continuous and precise spiral circulating raceway. Since the forming protrusions 14c of the multiple sliders 14 are arranged along the spiral direction, the entire spiral raceway can be pressed and formed in one forming process.

[0063] Combination Figure 3 As shown, during the mold opening stage, the upper mold plate 11 moves upward in the reverse direction, and the core rod 16 exits the gap of the slider 14. At this time, while the reset cylinder 17 drives the first end of the slider 14 to move radially, the reset bushing 22, driven by the transmission rod 23 and the ejector rod 25, acts on the second end of the slider 14, causing the slider 14 to retract radially inward and return to its initial position, ensuring that the inner wall of the nut smoothly disengages from the slider 14. The tapered guide surface 22a of the reset bushing 22 cooperates with the conical surface 14d of the slider 14, which can achieve smooth guidance during the reset process and avoid the slider 14 from jamming or shifting. After the entire mold opening action is completed, the ball screw nut blank can be taken out from the groove 21a of the lower mold plate 21, ready for subsequent heat treatment or finishing processes.

[0064] In the description of this utility model, it should be understood that the terms "center," "longitudinal," "transverse," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0065] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this utility model, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0066] In this utility model, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0067] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A device for preparing ball screw nuts, characterized in that, include: The upper mold assembly includes an upper template and a movable plate. The movable plate is located below the upper template and can move up and down relative to it. The movable plate is provided with a plurality of sliders distributed along the circumference. A core rod is fixedly installed at the bottom of the upper template. The outer surface of the slider has forming protrusions for forming a circulating ball track, and the forming protrusions of the plurality of sliders are arranged in a spiral direction. The lower mold assembly includes a lower template having a groove for placing a nut blank; During the mold closing process, the slider is inserted into the nut blank, the movable plate first abuts against the lower template, and then the upper template continues to move downward. The core rod is inserted into the gap between the sliders and drives the sliders to move radially outward, so that the forming protrusions on the surface of the sliders form a circulating ball track on the inner wall of the blank.

2. The apparatus for preparing a ball screw nut according to claim 1, characterized in that: The slider has a body extending axially, a guide block arranged radially at the first end of the body, and a guide groove on the movable plate that slides with the guide block.

3. The apparatus for preparing a ball screw nut according to claim 1, characterized in that: The movable plate is provided with a plurality of reset cylinders arranged in a circle, and each reset cylinder corresponds to the slider. Its moving end abuts against the slider to drive the first end of the slider to move radially inward.

4. The apparatus for preparing a ball screw nut according to claim 2, characterized in that: The second end of the slider has a conical surface, and the conical surfaces of multiple sliders together form a conical surface; the lower mold assembly also includes a reset bushing, which pushes the second end of the slider to move radially inward when the mold is opened.

5. The apparatus for preparing a ball screw nut according to claim 4, characterized in that: The reset bushing has a tapered guide surface that mates with the conical surface; when the mold is closed, the reset bushing moves toward the slider, and the tapered guide surface abuts against the conical surface to drive the slider to move radially inward.

6. The apparatus for preparing a ball screw nut according to claim 5, characterized in that: The lower mold assembly includes a transmission rod and a push rod. One end of the transmission rod is fixedly connected to the reset bushing, and the push rod pushes the other end of the transmission rod to drive the reset bushing to move in the direction of the slider.

7. The apparatus for preparing a ball screw nut according to claim 2, characterized in that: A limiting ring is fixedly installed on the lower template. When the mold is closed, the outer surface of the slider abuts against the inner diameter of the limiting ring to form a limit.

8. The apparatus for preparing a ball screw nut according to claim 1, characterized in that: The upper template and the movable plate are connected by a nitrogen spring or an overpressure relief cylinder.

9. The apparatus for preparing a ball screw nut according to claim 1, characterized in that: The core rod is truncated pyramidal in shape, with its outer surface being the pressure-applying surface and the inner surface of the slider being the pressure-receiving surface. The sliding contact between the pressure-applying surface and the pressure-receiving surface converts the axial movement of the core rod into the radial movement of the slider.

10. A ball screw nut, characterized in that: It is prepared by the apparatus according to any one of claims 1 to 9.

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