Ball screw splicing nut machining method, nut and electric cylinder

Abstract

The present disclosure provides a processing method of a spliced nut of a ball screw, a nut and an electric cylinder. The processing method of the spliced nut of the ball screw comprises: rotating and installing a first end of a processing auxiliary tool into an inner hole of a first nut, the processing auxiliary tool comprising a first end, a second end and a connecting part, and the first end and the second end are respectively provided with aligned first and second helical grooves; the first helical groove is connected with a first inner channel of the first nut through balls; the second nut is rotated and installed to the second end, and the second helical groove is connected with a second inner channel of the second nut through balls; the first and second nuts are positioned; the first and second nuts are fixedly connected into a spliced nut; and the processing auxiliary tool is removed. The two nuts are positioned by the processing auxiliary tool, so that the inner channels thereof are aligned, thereby ensuring that the inner channels of the two nuts for splicing are accurately connected.

Description

Technical Field

[0001] This disclosure relates to the field of machinery, and in particular to a method for processing a splicing nut for a ball screw, a nut, and an electric cylinder. Background Technology

[0002] Linear drives play a crucial role in industrial applications, and the field has consistently pursued the development of linear drive systems with high aspect ratios and high load densities. Reverse ball screws, as a next-generation design with small radial dimensions and high load density, hold immense promise for applications in smart manufacturing and artificial intelligence equipment. However, due to limitations in current manufacturing processes, it is impossible to produce nuts for small reverse ball screws with long strokes, thus failing to meet the market demand for long-stroke applications.

[0003] Reverse ball screws have a smaller radial dimension, requiring precision machining to create grooves in the inner hole of the nut. However, the precision machining process makes it difficult, or even impossible, to manufacture small nuts, resulting in the inability to directly produce long nuts. In contrast, in a reverse ball screw, the rotation of the nut drives the linear movement of the screw. The stroke of the reverse ball screw depends on the length of the nut, making it crucial to increase the length of the nut. Summary of the Invention

[0004] This disclosure provides a method for processing splicing nuts for ball screws, a nut, and an electric cylinder.

[0005] In a first aspect, this disclosure provides a method for processing spliced ​​nuts for ball screws, characterized by comprising: rotating a first end of a processing auxiliary tool into the inner hole of a first nut, wherein the processing auxiliary tool includes a first end, a second end, and a connecting portion connecting the first end and the second end, wherein the first end and the second end are both cylindrical with the same outer diameter, and the outer circumference of the first end and the second end are respectively provided with a first helical groove and a second helical groove, the first helical groove and the second helical groove being aligned; a ball is disposed in the first helical groove, and the first helical groove is connected to the first inner groove of the first nut through the ball; rotating a second nut into the second end, wherein a ball is disposed in the second helical groove, and the second helical groove is connected to the second inner groove of the second nut through the ball; positioning the first nut and the second nut so that the first inner groove and the second inner groove are aligned and spliced; fixing the first nut and the second nut together to obtain a spliced ​​nut; and removing the processing auxiliary tool from the spliced ​​nut.

[0006] In some embodiments, the outer diameter of the connecting portion is smaller than the outer diameters of the first end and the second end.

[0007] In some embodiments, the first end, the second end, and the connecting portion are all cylindrical and have the same outer diameter.

[0008] In some embodiments, a third spiral groove is provided on the outer periphery of the connecting portion, and the third spiral groove is connected to and aligned with the first spiral groove and the second spiral groove respectively.

[0009] In some embodiments, a first ball return channel is provided on the first end, and a second ball return channel is provided on the second end. The first ball return channel and the first spiral groove are connected to form a first circulating raceway; the second ball return channel and the second spiral groove are connected to form a second circulating raceway.

[0010] In some embodiments, the first ball return channel extends through the first end in an axial direction, and a pair of first circulators are disposed at both ends of the first end to connect the first ball return channel with the first spiral groove; the second ball return channel extends through the second end in an axial direction, and a pair of first circulators are disposed at both ends of the second end to connect the second ball return channel with the second spiral groove.

[0011] In some embodiments, the first end and the second end include a surface circulator that connects two adjacent channels of the first spiral groove or two adjacent channels of the second spiral groove.

[0012] In some embodiments, a plurality of circumferentially distributed mounting holes are provided on the outer periphery of the first end, and a plurality of circumferentially distributed mounting holes are provided on the outer periphery of the second end; the surface circulator includes a second circulator, which is installed in the mounting holes; the second circulator is provided with a second circulation channel penetrating the second circulator, and the second circulation channel connects two adjacent channels of the first spiral groove or two adjacent channels of the second spiral groove.

[0013] In some embodiments, the second circulator is composed of two half-circulators joined together, and the two half-circulators are arranged symmetrically at the left and right centers; each half-circulator is provided with a guide groove, the guide groove including an inwardly concave section and an outwardly convex section; the concave section of the guide groove of one half-circulator is complementary to the convex section of the guide groove of the other half-circulator, forming the second circulation channel.

[0014] In some embodiments, the surface circulator includes a third circulator, which includes a grooved surface and a connecting surface. The grooved surface is an arched surface, and multiple third circulation channels extending in the circumferential direction are formed on the grooved surface. The outer periphery of the first end and the outer periphery of the second end include a mounting surface and a threaded surface. The threaded surface of the first end and the threaded surface of the second end are respectively provided with a first helical groove and a second helical groove. The connecting surface is engaged with the mounting surface, the grooved surface matches the outer periphery of the threaded surface, and the third circulation channels connect two adjacent channels of the first helical groove or two adjacent channels of the second helical groove.

[0015] In some embodiments, retainers are provided in the first and second helical grooves to space adjacent balls apart.

[0016] In some embodiments, the retainer is provided with a plurality of positioning holes, and the ball is disposed in the positioning holes, so that the ball can rotate in the positioning holes without coming out.

[0017] In some embodiments, a stop mechanism is provided at both ends of the first spiral groove and a stop mechanism is provided at both ends of the second spiral groove to limit the range of movement of the retainer along the first spiral groove or the second spiral groove.

[0018] In some embodiments, the method further includes: before splicing, grooving the contacting ends of the first nut and the second nut.

[0019] In some embodiments, the method further includes: providing an axial gap at the ends of the first nut and the second nut that are in contact with each other, so that the first inner channel and the second inner channel are aligned and spliced.

[0020] In some embodiments, the first end is provided with a first connecting mechanism, and / or the second end is provided with a second connecting mechanism; the push rod is connected to the first connecting mechanism and / or the second connecting mechanism to fix the machining auxiliary tool or drive the machining auxiliary tool to rotate.

[0021] Secondly, this disclosure provides a nut, which is a spliced ​​nut obtained according to the spliced ​​nut processing method for ball screws described in the first aspect of this disclosure.

[0022] Thirdly, embodiments of this disclosure provide an electric cylinder, including a drive assembly, a ball screw, and the nut described in the second aspect of embodiments of this disclosure.

[0023] This disclosure provides a method for machining splicing nuts for ball screws. The first helical groove at the first end of the machining auxiliary tool is aligned with the second helical groove at the second end. When machining splicing nuts, the inner grooves of the two nuts positioned by the machining auxiliary tool are also aligned, thereby ensuring that the inner grooves of the two nuts used for splicing are precisely connected. This is beneficial for achieving splicing nuts of any length, especially when the ball screw is small and requires precision machining, and it is beneficial for increasing the stroke of the ball screw. Attached Figure Description

[0024] Figure 1 A schematic perspective view of a machining aid tool according to some embodiments is shown.

[0025] Figure 2 A schematic perspective view of a machining aid tool in the nut assembly process according to some embodiments is shown.

[0026] Figure 3 A schematic cross-sectional view and a partially enlarged view of the machining aid tool according to some embodiments during the nut splicing process are shown.

[0027] Figure 4 A schematic perspective view of the first nut before assembly, according to some embodiments, is shown.

[0028] Figure 5 A schematic perspective view of a first circulator according to some embodiments is shown.

[0029] Figure 6 A partial schematic cross-sectional view of a machining aid tool using a first circulator according to some embodiments is shown.

[0030] Figure 7 A partial schematic perspective view of a machining aid using a surface circulator according to some embodiments is shown.

[0031] Figure 8 A schematic perspective view of a second circulator according to some embodiments is shown.

[0032] Figure 9 A schematic perspective view of a semi-circulator according to some embodiments is shown.

[0033] Figure 10 A schematic perspective view of a third circulator according to some embodiments is shown.

[0034] Figure 11 A partial schematic perspective view of a machining aid tool using a third circulator according to some embodiments is shown.

[0035] Figure 12 A schematic perspective view of a retainer according to some embodiments is shown.

[0036] Figure 13 A schematic perspective view of a retainer disposed on a first end or a second end according to some embodiments is shown.

[0037] Figure 14 A schematic perspective view of a machining aid for nut splicing, according to some embodiments, is shown.

[0038] Figure 15 A schematic flowchart of a processing method for nut splicing according to some embodiments is shown.

[0039] Figure 16 A schematic perspective view of an electric cylinder according to some embodiments is shown.

[0040] Figure 17 A schematic cross-sectional view of an electric cylinder according to some embodiments is shown.

[0041] Explanation of reference numerals in the attached figures:

[0042] 1. Machining auxiliary tool; 11. First end; 111. First spiral groove; 12. Second end; 121. Second spiral groove; 13. Connecting part; 14. Retainer; 15. Ball bearing; 16. Positioning hole; 17. Stopping mechanism; 2. First nut; 21. First inner channel; 3. Second nut; 31. Second inner channel; 4. First circulator; 401. First surface; 402. Second surface; 403. Third surface; 404. Fourth surface; 411. First port; 412. Second port; 42. First circulation channel; 43. Main body; 44. Positioning block; 5. Second circulator; 51. Second circulation channel; 53. Semi-circulator; 531. Guide groove; 6. Third circulator; 61. Third circulation channel; 800. Electric cylinder. Detailed Implementation

[0043] To enable those skilled in the art to better understand the technical solutions of this disclosure, the technical solutions of this disclosure will be described in detail below with reference to the accompanying drawings.

[0044] Exemplary embodiments will be described more fully below with reference to the accompanying drawings; however, these exemplary embodiments may be embodied in different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will enable those skilled in the art to fully understand the scope of this disclosure.

[0045] Where there is no conflict, the various embodiments of this disclosure and the features thereof in the embodiments may be combined with each other.

[0046] As used herein, the term “and / or” includes any and all combinations of one or more related enumerated entries.

[0047] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit this disclosure. As used herein, the singular forms “a” and “the” are also intended to include the plural forms unless the context clearly indicates otherwise. It will also be understood that when the terms “comprising” and / or “made of” are used in this specification, the presence of the stated feature, integral, step, operation, element, and / or component is specified, but the presence or addition of one or more other features, integrals, steps, operations, elements, components, and / or groups thereof is not excluded.

[0048] The embodiments described herein can be described with reference to plan views and / or cross-sectional views using the ideal schematic diagrams of this disclosure. Therefore, the example illustrations can be modified according to manufacturing techniques and / or tolerances. Therefore, the embodiments are not limited to those shown in the drawings, but include modifications to configurations formed based on manufacturing processes. Therefore, the areas illustrated in the drawings are schematic in nature, and the shapes of the areas shown in the figures illustrate specific shapes of areas of an element, but are not intended to be limiting.

[0049] Unless otherwise specified, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art. It will also be understood that terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with their meaning in the context of the relevant art and this disclosure, and will not be interpreted as having an idealized or overly formal meaning, unless expressly so defined herein.

[0050] A ball screw is a mechanical linear actuator, mainly composed of a screw shaft and a nut. Within the nut are multiple small balls or rollers that roll within matching helical grooves. The primary function of a ball screw is to convert rotational motion into linear motion. In this conversion process, the ball nut can accurately and stably transmit force to static or dynamic loads, and this force transmission exhibits good repeatability. A key feature of ball screws is the use of balls within the helical grooves, significantly reducing the mechanical contact between the screw shaft and the nut, replacing sliding friction with rolling friction, thus effectively improving power conversion efficiency. A ball screw mainly consists of a screw shaft, a nut, and balls.

[0051] The lead screw shaft is the core component of a ball screw. Its main function is to receive rotational force and rotate around its own axis, thus converting rotational motion into linear motion. Generally, a motor is located at one end of the shaft, providing power for its rotation. The lead screw shaft is cylindrical in shape, with continuous ball grooves on its surface. These grooves extend spirally along the length of the lead screw shaft, forming the thread of the screw. The ball grooves formed by the ball grooves serve as the running track for the balls, and their contours can be either semi-circular or Gothic arc. The semi-circular contour is composed of a single curve, while the Gothic arc contour is formed by two curves forming an ellipse. These two contours result in different contact conditions with the ball bearing. Furthermore, ball screws are also classified as right-hand ball screws and left-hand ball screws.

[0052] In this disclosure, pitch is the axial distance between two consecutive helical grooves. In this disclosure, lead is the linear distance traveled along the screw axis when the screw completes one rotation (360 degrees). Increasing the lead of a ball screw increases both the linear distance and speed, but reduces the number of balls that can be accommodated around the screw shaft, thus decreasing the load capacity.

[0053] The nut of a ball screw is a cylindrical component containing balls, a circulation system, and an inner groove aligned with the screw shaft groove. The nut can be configured with ball circulation channels, which are the closed paths of the balls. Multi-loop ball nuts have two or more independent closed paths and can withstand greater loads than single-loop ball nuts. Furthermore, the number of revolutions in the circulation channel describes the number of times the ball rotates around the channel before the next cycle; the relationship between the number of revolutions and the circulation channel varies depending on the recirculation method used in the ball screw. The ball recirculation system in the nut allows the balls to be "reclaimed," that is, returned to the starting point within the loop, guiding the balls back to their original positions.

[0054] Reverse ball screws have a small radial dimension, requiring precision machining to create grooves in the inner bore of the nut. However, the precision machining process makes it difficult, or even impossible, to produce long nuts when the length-to-diameter ratio (nut length / nut diameter) is large. In reverse ball screws, the rotation of the nut drives the linear movement of the screw, and the stroke of the reverse ball screw depends on the length of the nut, making it crucial to increase the length-to-diameter ratio of the nut. To join multiple short nuts into a long nut, precise alignment of the inner grooves of each short nut is essential. Currently, precise groove alignment is not achievable, or there are limitations on the radial dimension of the nuts, allowing only nuts with a radial dimension larger than a certain size to be joined, thus limiting the application scenarios of reverse ball screws.

[0055] Figure 1 This is a schematic perspective view of a tool for splicing nuts according to some embodiments. Figure 2A schematic perspective view of the tools used in the nut assembly process according to some embodiments. Figure 3 Schematic cross-sectional view and partially enlarged view of the tool during the nut assembly process according to some embodiments. In some embodiments, reference is made to... Figures 1 to 3 The processing auxiliary tool 1 for splicing nuts on a ball screw disclosed herein includes a first end 11, a second end 12, and a connecting portion 13 connecting the first end 11 and the second end 12. In some embodiments, the connecting portion 13 is located between the first end 11 and the second end 12. In some embodiments, the first end 11, the second end 12, and the connecting portion 13 are integrally formed. In some embodiments, the processing auxiliary tool 1 may be formed of a metal material (e.g., stainless steel) or other materials (e.g., plastic, resin).

[0056] In some embodiments, both the first end 11 and the second end 12 are cylindrical and have the same outer diameter. In some embodiments, the outer periphery of the cylinders of the first end 11 and the second end 12 are respectively provided with a first helical groove 111 and a second helical groove 121, and the first helical groove 111 and the second helical groove 121 are aligned. Therefore, the structures of the first end 11 and the second end 12 can be identical. In some embodiments, the alignment of the first helical groove 111 and the second helical groove 121 means that if the first helical groove 111 and the second helical groove 121 extend toward the connecting portion 13, a continuous helical groove can be formed.

[0057] In some embodiments, such as Figure 2 and Figure 3 As shown, during the nut splicing process, the first helical groove 111 is connected to the first inner groove 21 of the first nut 2 through a ball, and the second helical groove 121 is connected to the second inner groove 31 of the second nut 3 to splice the first nut 2 and the second nut 3 together.

[0058] By aligning the first helical groove 111 and the second helical groove 121, the inner grooves of the two nuts (e.g., nuts 2 and 3) positioned by the machining auxiliary tool 1 are also aligned, thereby ensuring that the inner grooves of the two nuts used for splicing are precisely aligned.

[0059] In some embodiments, such as Figure 3 As shown, the machining auxiliary tool 1 is dumbbell-shaped, with the first end 11 and the second end 12 forming a dumbbell-shaped double head. At this time, the connecting part 13 is recessed relative to the first end 11 and the second end 12, which facilitates the splicing operation between nuts.

[0060] In some embodiments, the machining auxiliary tool 1 is cylindrical in shape, with the first end 11, the second end 12, and the connecting portion 13 all being cylindrical with the same outer diameter; that is, the machining auxiliary tool 1 is cylindrical in its entirety. In some embodiments, a third helical groove (not shown) is provided on the cylindrical outer periphery of the connecting portion 13, and the third helical groove is aligned with both the first helical groove 111 and the second helical groove 121. In some embodiments, the first helical groove 111, the second helical groove 121, and the third helical groove may be continuous or discontinuous. If continuous, a continuous helical groove can be formed on the outer periphery of the machining auxiliary tool 1, in which case the helical groove penetrates the outer circumference of the cylinder.

[0061] In some embodiments, the first helical groove 111 and the second helical groove 121 can be connected by the inner groove of the ball and the nut, thereby reducing the contact area between the machining auxiliary tool 1 and the nut, and thus reducing the frictional resistance between the machining auxiliary tool 1 and the nut. In some embodiments, the ball can be made of metal, such as stainless steel.

[0062] In this embodiment of the present disclosure, a circulating raceway can be provided on the outer periphery of the first end 11 and the second end 12, and the ball can circulate in the circulating raceway on the outer periphery of the first end 11 or the second end 12, thereby not limiting the stroke.

[0063] In this embodiment of the present disclosure, a circulating raceway can be formed by the ball return channel, or a circulating raceway can be formed on the outer periphery of the first end 11 and the second end 12 to realize the circulating rolling of the balls.

[0064] In some embodiments, a first ball return channel is provided on the first end 11, and a second ball return channel is provided on the second end 12. The first ball return channel is connected to the first spiral groove 111 to form a first circulating raceway; the second ball return channel is connected to the second spiral groove 121 to form a second circulating raceway.

[0065] Figure 6 This is a partial cross-sectional schematic diagram of the first end 11 or the second end 12. Figure 6 The image shows the ball return channel and the first circulator. In some embodiments, reference is made to... Figure 6 As shown, the first ball return channel extends through the first end 11 in the axial direction, and a pair of first circulators 4 are disposed at both ends of the first end 11 to connect the first ball return channel with the first spiral groove 111; the second ball return channel extends through the second end 12 in the axial direction, and a pair of first circulators 4 are disposed at both ends of the second end 12 to connect the second ball return channel with the second spiral groove 121.

[0066] In some embodiments, such as Figure 5As shown, the first circulator 4 includes a first surface 401, a second surface 402, and a third surface 403, which intersect each other. A first port 411 is provided on the third surface 403, a second port 412 is provided on the second surface 402, and a first circulation channel 42 is provided on the first surface 411. The first circulation channel 42 passes through the first circulator 4, connecting the first port 411 and the second port 412. The first port 411 is engaged with the first ball return channel or the second ball return channel, and the second port 412 is engaged with one end of the channel on the outer periphery of the first end 11 or the channel on the outer periphery of the second end 12, forming a first circulation raceway or a second circulation raceway.

[0067] In some embodiments, such as Figure 5 As shown, the first circulator 4 includes a main body 43 and a positioning block 44. The main body 44 includes a first surface 401, a second surface 402, and a fourth surface 404 parallel to the third surface 403. The positioning block 44 protrudes from the fourth surface 404. The first circulation channel 42 passes through the main body 43 and the positioning block 44. Positioning grooves matching the shape of the positioning block 44 are respectively provided at both ends of the first ball return channel or the second ball return channel. Mounting grooves matching the shape of the main body 43 are provided at both ends of the first end 11 or the second end 12. The positioning grooves are set in the mounting grooves. The main body 43 cooperates with the mounting grooves, and the positioning block 44 cooperates with the positioning grooves to mount the first circulator 4 on the first end 11 or the second end 12.

[0068] In some embodiments, the first end 11 and the second end 12 include a surface circulator that connects two adjacent channels of the first spiral groove 111 or two adjacent channels of the second spiral groove 121.

[0069] Figure 7 This is a partial schematic diagram of the first end 11 or the second end 12. In some embodiments, reference is made to... Figure 7 As shown, a plurality of circumferentially distributed mounting holes are provided on the outer periphery of the first end 11, and a plurality of circumferentially distributed mounting holes are provided on the outer periphery of the second end 12; the surface circulator includes a second circulator 5, which is installed in the mounting holes; as Figure 8 As shown, the second circulator 5 is provided with a second circulation channel 51 that runs through the second circulator 5. The second circulation channel 51 connects two adjacent channels of the first spiral groove 111 or two adjacent channels of the second spiral groove 121.

[0070] In some embodiments, such as Figure 9As shown, the second circulator 5 is composed of two half-circulators 53, which are arranged symmetrically from left to right. Each half-circulator 53 is provided with a guide groove 531, which includes an inwardly concave section and an outwardly convex section. The concave section of the guide groove 531 of one half-circulator 53 complements the convex section of the guide groove 531 of the other half-circulator 53, forming the second circulation channel 51.

[0071] Figure 11 This is a partial schematic diagram of the first end 11 or the second end 12. In some embodiments, reference is made to... Figure 10 , Figure 11 As shown, the surface circulator includes a third circulator 6, which includes a grooved surface and a connecting surface. The grooved surface is an arched surface, and multiple third circulation channels 61 extending in the circumferential direction are formed on the grooved surface. The outer periphery of the first end 11 and the outer periphery of the second end 12 include a mounting surface and a threaded surface. A first spiral groove 111 and a second spiral groove 121 are respectively provided on the threaded surface of the first end 11 and the threaded surface of the second end 12. The connecting surface is connected to the mounting surface, and the outer periphery of the grooved surface matches the outer periphery of the threaded surface. The third circulation channels 61 connect two adjacent channels of the first spiral groove 111 or two adjacent channels of the second spiral groove 121.

[0072] In some embodiments, reference Figure 12 and Figure 13 As shown, retainers 14 are provided in the first helical groove 111 and the second helical groove 121 to space adjacent balls 15 apart. This prevents the balls 15 from rubbing against each other and increasing resistance. In some embodiments, the retainers 14 have a helical shape consistent with the first helical groove 111 and the second helical groove 121.

[0073] In some embodiments, reference Figure 12 and Figure 13 As shown, the retainer 14 is provided with a positioning hole 16, allowing the ball 15 to rotate within the positioning hole 16 without falling out. In some embodiments, the positioning hole 16 of the retainer 14 has a limiting structure that matches the shape of the ball 15, preventing the ball 15 from falling out of the positioning hole 16. In some embodiments, the retainer 14 may be a flexible injection-molded elastomer made of plastic, such as a flat injection molded elastomer. In some embodiments, such as Figure 13 As shown, the retainer 14 is spirally wound around the first end 11. After the ball 15 is installed in the spiral groove of the tool using the retainer 14, when the tool rotates relative to the nut, the ball 15 can rotate in the positioning hole 16 of the retainer 14, thereby rolling in the spiral groove, and the retainer 14 moves along the spiral groove together. It should be understood that the same retainer 14 can be installed on the second end 12.

[0074] In some embodiments, such as Figure 13 As shown, a stop mechanism 17 is provided on the axial end side of the first end 11 opposite to the connecting portion 13 and on the axial end side of the second end 12 opposite to the connecting portion 13 to prevent further movement of the retainer 14. Therefore, stop mechanisms 17 can be provided at both ends of the machining auxiliary tool 1 to limit the stroke of the retainer 14, thereby limiting the tool's stroke. For example, when the retainer 14 moves to the position of the stop mechanism 17, stopping the retainer 14 increases the resistance to further linear movement of the machining auxiliary tool 1, thus limiting the stroke and preventing the ball bearing 15 from dislodging from the helical groove. Of course, since the tool will eventually retract, even if the ball bearing falls out, it will not affect the process; therefore, the stop mechanism 17 is not necessary.

[0075] In some embodiments, a first connecting mechanism is provided on the axial end side of the first end 11 opposite to the connecting portion 13. In some embodiments, such as Figure 14 As shown, a second connecting mechanism is provided on the axial end side of the second end 12 opposite to the connecting part 13. The first connecting mechanism and the second connecting mechanism are used to connect with the push rod. Therefore, connecting mechanisms can be provided at one or both ends of the machining auxiliary tool 1. When the machining auxiliary tool 1 is installed after the first nut 2 and the second nut 3 is installed on the machining auxiliary tool 1, it is convenient to fix the machining auxiliary tool 1 with the push rod and prevent the machining auxiliary tool 1 from rotating so that the second nut 3 cannot be installed. After the two nuts are welded together, it is convenient to drive the machining auxiliary tool 1 to rotate with the push rod, thereby removing or disengaging the machining auxiliary tool 1 from the splicing nut.

[0076] like Figure 15 As shown, another embodiment of this disclosure provides a processing method for splicing nuts. This processing method includes step S101: rotating the first end 11 of a processing auxiliary tool 1 into the inner hole of a first nut 2. The processing auxiliary tool 1 includes a first end 11, a second end 12, and a connecting portion 13 connecting the first end 11 and the second end 12. Both the first end 11 and the second end 12 are cylindrical with the same outer diameter. The outer circumference of the cylinders of the first end 11 and the second end 12 are respectively provided with a first helical groove 111 and a second helical groove 121. The first helical groove 111 and the second helical groove 121 are aligned. The first helical groove 111 is connected to the first inner groove 21 of the first nut 2 via a ball bearing, for example, through a rotatable connection. It should be understood that the tool used in the processing method of this embodiment is the processing auxiliary tool 1 described above; therefore, the structural description of the processing auxiliary tool 1 will not be repeated here.

[0077] In some embodiments, the processing method of this disclosure further includes step S102: rotating the second nut 3 onto the second end 12 of the processing auxiliary tool 1 until there is an axial gap between the second nut 3 and the first nut 2, wherein the second helical groove 121 is connected to the second inner channel 31 of the second nut 3 by ball bearings, for example, by a rotatable connection. In some embodiments, the width of the axial gap can be between 0.5 and 1.5 times the pitch of the first helical groove 111 or the second helical groove 121.

[0078] In some embodiments, the processing method of this disclosure further includes step S103: positioning the first nut 2 and the second nut 3 in the presence of axial clearance. That is, when the two nuts (e.g., the first nut 2 and the second nut 3) are spliced ​​and positioned, there is an axial clearance between the two nuts. When the two nuts are positioned using the processing auxiliary tool 1, it is equivalent to leaving a margin for error. Under the drive of the processing auxiliary tool 1, the two nuts can move axially relative to each other, thereby ensuring the alignment accuracy of the inner grooves of the nuts. After contact positioning, since the first helical groove 111 and the second helical groove 121 are aligned, the inner grooves of the first nut 2 and the second nut 3 are also aligned, thereby achieving precise docking of the inner grooves between the first nut 2 and the second nut 3.

[0079] In some embodiments, the processing method of this disclosure further includes step S104: fixing the first nut 2 and the second nut 3 together to obtain a spliced ​​nut. By fixing the first nut 2 and the second nut 3 together, the length of the spliced ​​nut is the sum of the lengths of the first nut 2 and the second nut 3, thereby doubling the length-to-diameter ratio of the spliced ​​nut. By continuing to splice using tools, the length of the spliced ​​nut can be further increased, thereby increasing the length-to-diameter ratio of the spliced ​​nut.

[0080] In some embodiments, the processing method of this disclosure further includes step S105: removing the processing auxiliary tool 1 from the splicing nut. Therefore, the processing method of this disclosure can achieve precise alignment of the inner groove of the nut while obtaining a nut with a large length-to-diameter ratio, solving the problem that nuts with small inner diameters and large length-to-diameter ratios cannot achieve precise machining of the inner groove.

[0081] In some embodiments, the processing method further includes: before splicing, grooved the contacting ends of the first nut and the second nut. In some embodiments, the junction of the two nuts needs to be grooved before splicing to ensure that the ball passes between the two nuts perpendicular to the groove cut, thereby making the inner grooves of the two nuts continuous. Figure 4 The results of groove machining on the end of the first nut are shown. Corresponding groove machining can be performed on the second nut so that the first nut and the second nut match and ensure that the ball passes between the two nuts perpendicular to the groove cut.

[0082] In some embodiments, fixing the first nut 2 and the second nut 3 together includes welding the first nut 2 and the second nut 3 together. In some embodiments, a suitable welding method such as laser welding can be used to weld the first nut 2 and the second nut 3 together.

[0083] In some embodiments, the aspect ratio of the splicing nut is from 1 to 100. In some embodiments, the aspect ratio of the splicing nut is 20, 30, 40, 50, 60, 70, 80, 90, 100, or any suitable value between them. This disclosure achieves precise alignment of the inner grooves of the nut by using tools for splicing, while obtaining nuts with large aspect ratios (virtually any length of long splicing nut can be obtained).

[0084] Another embodiment of this disclosure provides a nut, which is a spliced ​​nut obtained by the above-described processing method for nut splicing.

[0085] like Figure 16 and Figure 17 As shown, another embodiment of this disclosure provides an electric cylinder 800, including the aforementioned nut or spliced ​​nut. In some embodiments, the electric cylinder 800 is a long-stroke integrated electric cylinder. The long spliced ​​nut manufactured using the above processing method achieves a greater stroke. Simultaneously, by adding multiple motors (e.g., each short nut used for splicing corresponds to one motor; the longer the nut length, the more motors can be added), a larger processing capacity and higher power electric cylinder system can be achieved. Based on the process of manufacturing long spliced ​​nuts, this disclosure utilizes the long motor chamber size provided by the long spliced ​​nut to integrate as many frameless motors as possible, thereby doubling the output power. Since the lifespan of the lead screw is positively correlated with the rated load, and the rated load is positively correlated with the nut length and motor power, this disclosure, by employing long spliced ​​nuts, allows for the integration of more frameless motors, resulting in a several-fold increase in the stroke, power, and lifespan of the electric cylinder.

[0086] During the operation of an electric cylinder, the motor drives the lead screw to rotate, thereby causing the nut to complete linear motion. The working principle of a planetary roller lead screw is as follows: the lead screw can be considered as the sun gear, the rollers as planet gears, and the nut as the central gear. When the lead screw rotates and the nut's circumferential direction is fixed, the rollers perform planetary-like motion in the circumferential direction. Simultaneously, through helical transmission, the rotational motion of the lead screw (or nut) is converted into the linear reciprocating motion of the nut (or lead screw). The working principle of a planetary roller lead screw is similar to that of a ball screw, i.e., a servo motor drives the lead screw to rotate, thereby causing the planetary roller nut assembly to drive the electric cylinder push rod to complete linear reciprocating push-pull motion.

[0087] Planetary roller screws can be classified into five types based on their structural composition and kinematic relationships: standard planetary roller screws, reverse planetary roller screws, circulating planetary roller screws, differential planetary roller screws, and bearing ring planetary roller screws. In reverse planetary roller screws, the nut serves as both the force transmission component and the rotor of the motor, exhibiting a high degree of integration and miniaturization. Various planetary roller screw drives are important actuators in electromechanical devices. Common electromechanical actuators can be divided into two types: integrated electromechanical actuators (I-EMA) and combined electromechanical actuators (C-EMA). A typical integrated electromechanical actuator structure consists of four parts: a DC brushless motor, a controller (mainly including speed, position, and torque controllers and a power converter), a reducer (gear drive or belt drive), and a planetary roller screw. A combined electromechanical actuator structure mainly consists of three parts: a planetary roller screw (including the screw, rollers, and nut), a motor (magnet and coil windings), and a controller (control, measurement, feedback unit, and corresponding interfaces). For a reverse planetary roller screw, the nut serves as both a force transmission component and a motor rotor. Linear servo is achieved through the meshing transmission of the screw, rollers, and nut, making it a truly integrated electromechanical actuator.

[0088] Example embodiments have been disclosed herein, and while specific terminology has been used, it is for illustrative purposes only and should be construed as such, and is not intended to be limiting. In some instances, it will be apparent to those skilled in the art that features, characteristics, and / or elements described in connection with particular embodiments may be used alone, or in combination with features, characteristics, and / or elements described in connection with other embodiments, unless otherwise expressly indicated. Therefore, those skilled in the art will understand that various changes in form and detail may be made without departing from the scope of this disclosure as set forth by the appended claims.

Claims

1. A method for processing splicing nuts for ball screws, characterized in that, include: The first end (11) of the machining auxiliary tool is rotated and installed into the inner hole of the first nut. The machining auxiliary tool includes the first end (11), the second end (12), and the connecting part (13) connecting the first end (11) and the second end (12). The first end (11) and the second end (12) are both cylindrical and have the same outer diameter. The outer circumference of the first end (11) and the second end (12) are respectively provided with a first spiral groove (111) and a second spiral groove (121). The first spiral groove (111) and the second spiral groove (121) are aligned. A ball is provided in the first spiral groove (111). The first spiral groove (111) is connected to the first inner channel of the first nut through the ball. The second nut is rotated and installed onto the second end (12), wherein a ball is provided in the second spiral groove (121), and the second spiral groove (121) is connected to the second inner channel of the second nut through the ball; Position the first nut and the second nut so that the first inner channel and the second inner channel are aligned and spliced. The first nut and the second nut are fixedly connected together to obtain a spliced ​​nut; Remove the machining aid from the splicing nut.

2. The method for processing splicing nuts for ball screws according to claim 1, characterized in that, The outer diameter of the connecting part (13) is smaller than the outer diameters of the first end (11) and the second end (12).

3. The method for processing splicing nuts for ball screws according to claim 1, characterized in that, The first end (11), the second end (12) and the connecting part (13) are all cylindrical and have the same outer diameter.

4. The method for processing splicing nuts for ball screws according to claim 1, characterized in that, The outer periphery of the connecting part (13) is provided with a third spiral groove, which is connected to and aligned with the first spiral groove (111) and the second spiral groove (121) respectively.

5. The method for processing splicing nuts for ball screws according to claim 1, characterized in that, A first ball return channel is provided on the first end (11), and a second ball return channel is provided on the second end (12). The first ball return channel is connected to the first spiral groove (111) to form a first circulating raceway; the second ball return channel is connected to the second spiral groove (121) to form a second circulating raceway.

6. The method for processing splicing nuts for ball screws according to claim 5, characterized in that, The first ball return channel extends through the first end (11) in the axial direction, and a pair of first circulators (4) are disposed at both ends of the first end (11) to connect the first ball return channel with the first spiral groove (111); The second ball return channel extends through the second end (12) in the axial direction, and a pair of first circulators (4) are set at both ends of the second end (12) to connect the second ball return channel with the second spiral groove (121).

7. The method for processing splicing nuts for ball screws according to claim 1, characterized in that, The first end (11) and the second end (12) include surface circulators that connect two adjacent channels of the first spiral groove (111) or two adjacent channels of the second spiral groove (121).

8. The method for processing splicing nuts for ball screws according to claim 7, characterized in that, The outer periphery of the first end (11) is provided with a plurality of mounting holes distributed in the circumferential direction, and the outer periphery of the second end (12) is provided with a plurality of mounting holes distributed in the circumferential direction; the surface circulator includes a second circulator (5), which is installed in the mounting holes; The second circulator (5) is provided with a second circulation channel (51) that runs through the second circulator (5), and the second circulation channel (51) connects two adjacent channels of the first spiral groove (111) or two adjacent channels of the second spiral groove (121).

9. The method for processing splicing nuts for ball screws according to claim 8, characterized in that, The second circulator (5) is composed of two semi-circulators (53) joined together, and the two semi-circulators (53) are arranged symmetrically from left to right. Each semi-circulator (53) is provided with a guide groove (531), which includes an inwardly concave section and an outwardly convex section. The concave section of the guide groove (531) of one semi-circulator (53) complements the convex section of the guide groove (531) of the other semi-circulator (53), forming the second circulation channel (51).

10. The method for processing splicing nuts for ball screws according to claim 7, characterized in that, The surface circulator includes a third circulator (6), which includes a groove surface and a connecting surface. The groove surface is an arched surface, and multiple third circulation channels (61) extending in the circumferential direction are opened on the groove surface. The outer periphery of the first end (11) and the outer periphery of the second end (12) include a mounting surface and a threaded surface. The first spiral groove (111) and the second spiral groove (121) are respectively provided on the threaded surface of the first end (11) and the threaded surface of the second end (12). The connecting surface is connected to the mounting surface, the groove surface matches the outer periphery of the threaded surface, and the third circulation channel (61) connects two adjacent channels of the first spiral groove (111) or two adjacent channels of the second spiral groove (121).

11. The method for processing splicing nuts for ball screws according to claim 1, characterized in that, Retainers are provided in the first spiral groove (111) and the second spiral groove (121) to separate adjacent balls.

12. The method for processing splicing nuts for ball screws according to claim 11, characterized in that, The retainer is provided with multiple positioning holes, and the ball is disposed in the positioning holes, so that the ball can rotate in the positioning holes without falling out.

13. The method for processing splicing nuts for ball screws according to claim 11, characterized in that, The first spiral groove (111) is provided with a stop mechanism at both ends, and the second spiral groove (121) is provided with a stop mechanism at both ends, for limiting the range of movement of the retainer (14) along the first spiral groove (111) or the second spiral groove (121).

14. The method for processing splicing nuts for ball screws according to any one of claims 1 to 13, characterized in that, Also includes: Before splicing, the contacting ends of the first nut and the second nut are grooved.

15. The method for processing splicing nuts for ball screws according to claim 14, characterized in that, Also includes: An axial gap is provided at the ends of the first nut and the second nut that are in contact with each other, so that the first inner channel and the second inner channel are aligned and spliced.

16. The method for processing splicing nuts for ball screws according to any one of claims 1 to 13, characterized in that, The first end (11) is provided with a first connecting mechanism, and / or the second end (12) is provided with a second connecting mechanism; the push rod is connected to the first connecting mechanism and / or the second connecting mechanism to fix the machining auxiliary tool or drive the machining auxiliary tool to rotate.

17. A nut, characterized in that, The nut is a spliced ​​nut obtained by the spliced ​​nut processing method for ball screws according to any one of claims 1 to 16.

18. An electric cylinder, characterized in that, Includes a drive assembly, a ball screw, and a nut as claimed in claim 17.

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