Standard multi-stage ring groove planetary roller screw

Abstract

The present application relates to the technical field of roller screw, and particularly relates to a standard multi-section ring groove planetary roller screw, which comprises a screw rod and a nut, the nut is sleeved on the screw rod, a plurality of engagement sections and transition sections between adjacent engagement sections are arranged on the inner side wall of the nut along the axial direction of the nut; a plurality of rollers are installed in the inner side of the nut through a planet carrier and cooperate with the screw rod and the engagement sections to realize the relative movement between the nut and the screw rod, the rollers are rotationally connected to the planet carrier, the plurality of rollers are circumferentially arranged on the inner side of the nut, and each roller is provided with a transmission section; wherein one transmission section is opposite to one engagement section, each engagement section comprises a plurality of first ring grooves which are arranged at intervals along the axial direction of the nut, and the transmission section comprises a plurality of second ring grooves which are arranged at intervals along the axial direction of the roller. The present application realizes the mass production of small lead roller screws at low cost through the design of the rollers and the ring grooves on the nut and the arrangement of the transition sections.

Description

Technical Field

[0001] This invention relates to the field of ball screw technology, and more particularly to a standard multi-segment annular groove planetary ball screw. Background Technology

[0002] Standard (positive) planetary roller screw pairs are high-load, high-precision transmission mechanisms used in weaponry, industrial robots, CNC machine tools, and industrial automation. There is an urgent, large-scale demand for standard (positive) planetary roller screw pairs in electric engineering machinery, CNC machine tools, and humanoid robots.

[0003] However, existing positive planetary roller screw pairs have the following drawbacks: they cannot be mass-produced on a large scale, cannot be mass-produced at low cost, have high noise and vibration, have large nut diameters that cannot be miniaturized and cannot be replaced by mainstream ball screws of the same type and size, cannot have miniaturized nut sizes, and can only achieve medium to large lead sizes, not small lead sizes.

[0004] The main components of a forward planetary roller screw pair are a multi-threaded nut with an internal gear, externally threaded rollers with external gears at both ends, and a multi-threaded screw. Since the nut and rollers are both composites of gears and threads, they are difficult to manufacture, costly, and expensive, and cannot be mass-produced at low cost.

[0005] In existing typical structures, such as patent application publication number CN104110474A, the roller screw mechanism has an internal gear ring structure in the nut, and externally threaded rollers with external gears at both ends. The rollers perform planetary motion of rotation and revolution within the nut. The gears at both ends of the rollers mesh with the internal gears inside the nut, resulting in vibration and noise from gear meshing. Moreover, as the speed of the screw or nut increases to over 2000 rpm, the noise and vibration increase significantly.

[0006] In existing structures, due to the presence of an internal gear ring in the nut, the nut diameter of a planetary roller screw is larger than that of a ball screw with the same lead screw pitch diameter. Furthermore, existing structures are commonly used for five- or six-start lead screws, with a very small number of smaller sizes using four or three starts. The pitch diameter of the rollers is 1 / 3, 1 / 4, or 1 / 2 of the lead screw pitch diameter. Due to the influence of the roller ratio, the radial dimension of the nut cannot be arbitrarily adjusted. This large radial dimension of the nut prevents traditional planetary roller screws from replacing the same specifications and dimensions in the most mainstream fields where ball screws are widely used, such as machine tools. This severely limits their market application.

[0007] Furthermore, when the lead screw's mean diameter is 1 / 3, 1 / 4, or 1 / 2, and the roller's mean diameter is around 2mm, the roller structure has the following form: hardness 58-62HRC, extremely small module gears with high hardness at both ends, and a composite high-precision, high-hardness thread throughout. This makes it extremely difficult to manufacture. In addition, the structural dimensions of the internal gear are superimposed, requiring a radial enlargement, which results in a large radial structural dimension of the nut. The minimum nut diameter is around 11mm, which cannot meet the requirement of a nut diameter of around 5.5mm for micro lead screws in the field of humanoid robots.

[0008] Furthermore, when the existing structure is applied to three- or four-start lead screws, the achievable physical lead is 1 mm. When the lead is 1 mm, the pitch is 0.333333 mm (lead = pitch × number of starters). A pitch of 0.333333 mm is already very difficult to manufacture, resulting in low processing efficiency, high processing costs, and making mass production impossible. Summary of the Invention

[0009] This invention addresses the following shortcomings of traditional forward planetary roller screw pairs: inability to achieve large-scale mass production, inability to achieve low-cost mass production, high noise and vibration, large nut diameter preventing miniaturization and replacement with mainstream ball screws of the same type and size, inability to miniaturize the nut size, and the limitation of achieving only medium to large leads. This invention provides a standard multi-segment annular groove planetary roller screw.

[0010] The technical solution adopted by this invention to solve its technical problem is:

[0011] A standard multi-segment annular groove planetary roller screw includes:

[0012] Lead screw, and

[0013] A nut, which is sleeved on a lead screw, has multiple engagement sections and transition sections located between adjacent engagement sections on its inner sidewall along its axial direction;

[0014] Multiple rollers are mounted inside the nut via a planetary carrier and cooperate with a lead screw and a meshing section to achieve relative movement between the nut and the lead screw. The rollers are rotatably connected to the planetary carrier and are circumferentially arranged inside the nut. Each roller is provided with a transmission section.

[0015] In this configuration, one transmission segment is opposite to one engagement segment. Each engagement segment includes a plurality of first annular grooves spaced apart along the axial direction of the nut. The transmission segment includes a plurality of second annular grooves spaced apart along the axial direction of the roller. The spacing d1 between adjacent first annular grooves, the spacing d2 between adjacent second annular grooves, and the pitch M of the thread on the lead screw are all equal.

[0016] This invention utilizes the cooperation of a lead screw, nut, and multiple rollers. The meshing section on the nut engages with the transmission section of the rollers to achieve axial positioning and transmission of the rollers. The rollers simultaneously mesh with the nut and lead screw via the transmission section, and through the design of transition sections between adjacent meshing sections, they achieve planetary motion between the lead screw and nut, converting the rotational motion of the lead screw into axial movement of the nut, or vice versa. This structure is simple overall with a clear transmission relationship. In this structure, each roller only needs to be machined with a small annular groove, completely breaking the precision machining limitations of traditional roller-gear-thread composite structures, reducing manufacturing difficulty and production costs, and also reducing vibration and noise during the operation of the linear actuation mechanism. Through the design of the transition section on the nut, even on a single-start lead screw, a stable structural layout of at least three rollers can be achieved, achieving smooth, non-locking, constant lead transmission, and even small lead movements from 0.2mm to 1mm.

[0017] To obtain the design length of the transition section, achieve relative axial movement between the nut and the lead screw, and realize precise segmented displacement control in the nut's axial direction, a mathematical basis is provided for the design of this planetary outer ring groove roller screw. The following design is made for the transition section and rollers:

[0018] Furthermore, the number of leads in the lead screw is 1, and among the plurality of rollers there is a reference roller, and the length of the transition segment between the i-th engagement segment and the (i-1)-th engagement segment is... In the formula, Let M be the included angle between any two adjacent rollers, and M be the pitch of the lead screw helix.

[0019] Furthermore, the number of threads of the lead screw is n, where n is a positive integer greater than 1. Among the multiple rollers, there are n reference rollers, which are arranged in a centrally symmetrical manner, and the area between adjacent reference rollers is a reference region.

[0020] Furthermore, in each of the aforementioned reference regions, the length of the transition segment between the i-th occlusal segment and the (i-1)-th occlusal segment... ,in, The angle between the roller corresponding to the k-th engagement segment and a reference roller at the end of its design interval is k=i or i-1.

[0021] Furthermore, in order to reduce structural complexity, the number of rollers is at least three. These three rollers are solid rollers. The concept of virtual rollers simplifies kinematic analysis and parameter design, thereby reducing structural complexity.

[0022] Furthermore, multiple reference rollers are positioned opposite the same engagement segment.

[0023] Furthermore, in order to optimize the roller arrangement and improve operational stability, the rollers are evenly distributed in the circumferential direction, resulting in balanced force and stable transmission. This prevents eccentric loading and vibration caused by uneven distribution of rollers in the outer ring groove. The multiple rollers are evenly distributed circumferentially around the screw.

[0024] Furthermore, the number of second annular grooves on each of the transmission segments is less than or equal to the number of first annular grooves in the corresponding meshing segments, and the number of second annular grooves on each of the transmission segments is greater than or equal to one.

[0025] Furthermore, a second ring tooth is formed on the transmission section through a second ring groove, and the tooth surface of the second ring tooth is a convex arc surface.

[0026] Furthermore, in order to improve the stability of the planetary carrier installation and prevent axial movement of the planetary carrier, a limiting component is provided on the nut, which is used to limit the axial slippage of the planetary carrier.

[0027] The beneficial effect of this invention is that, by constraining the rollers axially with a planetary carrier, the rollers can only rotate around their own axis when the screw rotates, while the planetary carrier drives the rollers to revolve as the nut and screw slide relative to each other. Multiple second annular grooves distributed axially on the roller surface form a mating interface with the corresponding first annular grooves on the inner side of the nut. By incorporating a transition section, when the rollers rotate, the inclined surface or curved profile of the annular groove sidewall interacts with the nut's annular groove, forcing the nut and rollers to displace together along the screw axially.

[0028] By offsetting the spacing of the meshing sections on the nut, this structure enables the nut to move relative to the screw along its axial direction using at least three rollers. This structure eliminates the traditional internal gear multi-threaded nut and external threaded rollers with external gears at both ends, eliminating the internal gear and external gear, and replacing them with a nut and rollers, with only an annular groove structure. It is simple and convenient to process, and can be mass-produced with high precision, on a large scale, and at low cost.

[0029] The nuts and rollers have only annular grooves and no gear meshing, which greatly reduces noise and vibration during use, achieving a low-noise and low-vibration effect.

[0030] The nut and rollers only have ring grooves, eliminating the internal gear ring in the nut and the external gear in the rollers. The fixed proportional relationship between the roller's mean diameter and the screw's mean diameter is eliminated, resulting in a significant reduction in the nut's outer diameter compared to traditional nuts. This allows for replacement with mainstream ball screws of the same type and size.

[0031] The nut and rollers only have annular grooves, eliminating the internal gear ring in the nut and the external gear in the rollers. The fixed proportional relationship between the roller's pitch diameter and the lead screw's pitch diameter is no longer present. Miniaturization of the lead screw also allows for miniaturization of the rollers. This miniaturization of the rollers ensures manufacturability, enabling high-precision, low-cost, large-scale production. The nut can be miniaturized, with a minimum diameter of less than 5.5mm, meeting the ultra-small structural size requirements of dexterous hands in the field of humanoid robots.

[0032] The nut and rollers only have annular grooves, eliminating the internal gear ring in the nut and the external gear in the rollers. The fixed proportional relationship between the roller's pitch diameter and the screw's pitch diameter is no longer used. Through a method of skipping groove spacing and an offset design of the meshing section spacing on the nut, this structure allows for a minimum of three rollers while maintaining a screw thread count of no more than three, with a minimum of one thread. It enables the lead to be equal to the pitch (lead = pitch × number of screw threads), and can achieve a small lead of approximately 0.5mm, making it suitable for large-scale, economical mass production in engineering applications, including humanoid robot dexterity hands. Attached Figure Description

[0033] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0034] Figure 1 This is a schematic diagram of the standard multi-segment annular groove planetary roller screw in Embodiment 1 of the present invention.

[0035] Figure 2 This is a schematic diagram of the nut structure in Embodiment 1 of the present invention.

[0036] Figure 3 This is a schematic diagram of the assembly relationship between the transmission part and the nut in Embodiment 1 of the present invention.

[0037] Figure 4 This is a schematic diagram of the roller structure in Embodiment 1 of the present invention.

[0038] Figure 5 This is a schematic diagram of the roller arrangement structure in Embodiment 1 of the present invention.

[0039] Figure 6 This is a schematic diagram of the relationship between the roller and the nut in Embodiment 1 of the present invention.

[0040] Figure 7 This is a schematic diagram of the assembly relationship between the transmission part and the nut in Embodiment 2 of the present invention.

[0041] Figure 8 This is a schematic diagram of the roller arrangement structure in Embodiment 2 of the present invention.

[0042] Figure 9This is a schematic diagram of the relationship between the roller and the nut in Embodiment 2 of the present invention.

[0043] Figure 10 This is a schematic diagram of the assembly relationship between the transmission part and the nut in Embodiment 3 of the present invention.

[0044] Figure 11 This is a schematic diagram of the roller arrangement structure in Embodiment 3 of the present invention.

[0045] Figure 12 This is a schematic diagram of the fit between the roller and the nut in Embodiment 3 of the present invention.

[0046] In the diagram: 1. Lead screw; 2. Nut; 21. First annular groove; 22. Engaging section; 23. Transition section; 24. Insertion groove; 3. Planetary carrier; 31. End plate; 32. Circular hole; 4. Roller; 41. Reference roller; 42. Secondary roller; 43. Transmission section; 44. Connecting section; 45. Second annular groove; 5. Limiting component. Detailed Implementation

[0047] The present invention will now be described in further detail with reference to the accompanying drawings. These drawings are simplified schematic diagrams, illustrating only the basic structure of the invention, and therefore only show the components relevant to the invention.

[0048] Example 1:

[0049] like Figures 1 to 6 As shown, a standard multi-segment annular groove planetary roller screw includes: a screw 1, a nut 2 ( Figure 2 To make the internal structure clear, nut 2 is cut in half (the actual nut 2 is a closed structure) and transmission part, which includes planetary carrier 3 and multiple rollers 4.

[0050] To facilitate the assembly of the roller 4, axial jamming will not occur when the roller 4 is axially assembled into the nut 2. The planetary carrier 3 is assembled inside the nut 2, and limiters 5 are provided at both ends to prevent the planetary carrier 3 from moving axially. The limiter 5 can be in the form of a retaining ring, in which case a groove 24 for installing the retaining ring is correspondingly opened on the inner wall of the nut 2; in other implementations, limit steps located at both ends of the planetary carrier 3 can be directly machined on the inner wall of the nut 2, or end plugs that are interference-fitted with the nut 2 and inserted into both ends can be used to achieve the limit.

[0051] To achieve smooth sliding between the lead screw 1 and the nut 2, the number of solid rollers 4 must be no less than three. The planetary carrier 3 consists of two end plates 31, and the rollers 4 have shaft-shaped connecting sections 44 at both ends. The end plates 31 have circular holes 32 for the connecting sections 44 to be inserted, allowing each roller 4 to rotate freely. Simultaneously, a stepped surface facing the connecting section 44 is provided between the connecting section 44 and the main body of the roller 4. When the connecting section 44 is inserted into the circular hole 32, this stepped surface abuts against the end of the planetary carrier 3, thereby defining the relative position of the rollers 4 and the planetary carrier 3.

[0052] In this embodiment, the lead screw 1 is a single-ended lead screw 1, meaning that the lead screw 1 has only one helix. The nut 2 is coaxially sleeved on the lead screw 1. The inner ring of the nut 2 has multiple axially arranged engagement sections 22, and transition sections 23 are provided between adjacent engagement sections 22. The planetary carrier 3 is rotatably connected to the nut 2. The roller 4 is rotatably connected to the planetary carrier 3.

[0053] Specifically, such as Figure 4 As shown, each roller 4 includes a drive section 43, which engages with a helical section on the lead screw 1. One drive section 43 also engages with a meshing section 22 on the nut 2 to constrain the roller 4, preventing relative axial displacement between the roller 4 and the nut 2. The area on the roller 4, excluding the drive section 43, is a smooth axis with a small diameter, thus creating clearances between it and both the meshing section 22 and the lead screw 1.

[0054] In this embodiment, the engagement section 22 is arranged along the axial direction, and a transition section 23 is formed between adjacent engagement sections 22. The transmission section 43 of a roller 4 is uniquely associated with the corresponding engagement section 22. When the planetary roller screw is working, the roller 4 and the screw 1 move relative to each other in the axial direction. The transmission section 43 cooperates with the corresponding engagement section 22 to constrain the roller 4 so that the roller 4 and the nut 2 have no relative axial displacement.

[0055] Specifically, adjacent engagement segments 22 are spaced apart by transition segments 23. If the roller 4 is projected onto the central axis of the lead screw 1, all transmission segments 43 will also be arranged at intervals in the projection direction. This ensures that the transmission segments 43 occupy different positions on the helical line of the lead screw 1, and that the roller 4 can rotate smoothly relative to the lead screw 1.

[0056] Preferably, the area on the roller 4, excluding the transmission section 43, is a smooth shaft. The outer wall of the smooth shaft area has a gap with the radial outer edge of the engagement section 22 on the nut 2 and the radial inner edge of the helix. The smooth shaft area is radially concave relative to the transmission section 43, ensuring that only the transmission section 43 engages with the helical and engagement section 22 of the lead screw 1, and that the smooth shaft area does not transmit power. Of course, the position of the smooth shaft area is determined based on the position of the transmission section 43.

[0057] Specifically, the engagement section 22 includes multiple parallel first annular grooves 21, which form first annular teeth on the inner wall of the nut 2. The transmission section 43 includes multiple parallel second annular grooves 45, which form second annular teeth on the roller 4. The tooth surfaces of the teeth formed by the second annular grooves 45 on the roller 4 are convex arc surfaces. The spacing d1 between adjacent first annular grooves 21, the spacing d2 between adjacent second annular grooves 45, and the pitch M of the thread on the lead screw 1 are all equal.

[0058] The second ring tooth is embedded in the first ring groove 21 of the meshing section 22. Power transmission is achieved using the ring tooth and ring groove. The roller 4 rotates on its own axis while revolving around the lead screw 1. The axial movement of the roller 4 is transmitted to the nut 2 through the first ring groove 21 and the second ring groove 45, and vice versa. A one-to-one correspondence between the first ring groove 21 and the second ring tooth is optimal. In practice, the number of first ring grooves 21 can be greater than the number of second ring grooves 45, and the number of first ring teeth can be greater than the number of second ring grooves 45. The number of second ring grooves 45 and the number of second ring teeth should be greater than or equal to one, ensuring that the second ring tooth can be correspondingly positioned in the first ring groove 21.

[0059] It should be noted that the cross-sectional shape of the first annular groove 21, the cross-sectional shape of the second annular groove 45, and the cross-sectional shape of the thread on the external thread screw 1 are not limited, and can be, but are not limited to, the following shapes: triangular, trapezoidal, circular arc, and involute tooth profile.

[0060] When the lead screw 1 is axially fixed and rotates, the nut 2 moves along the axial direction of the lead screw 1, and the planetary carrier 3 and multiple rollers 4 revolve around the lead screw 1. The planetary carrier 3 moves with the nut 2, and each roller 4 rotates on its own axis. When the nut 2 is axially fixed and rotates, the lead screw 1 moves along the axial direction of the nut 2, and the planetary carrier 3 and multiple rollers 4 revolve around the lead screw 1. Each roller 4 rotates on its own axis.

[0061] Specifically, such as Figure 5 , 6 As shown, in this embodiment, the lead screw 1 has only one thread (the lead screw 1 has only one helical section), and the length of the transition section 23 is... , In the formula, any roller 4 is taken as a virtual starting point (that is, the roller 4 is considered as the reference roller 41, and there is only one reference roller 41 in this embodiment). M is the included angle between any two adjacent rollers 4 starting from the reference roller 41, and M is the pitch of the helix. Since a single-start lead screw 1 is used, the minimum lead of the planetary roller screw in this embodiment is the pitch of the helix of the lead screw 1.

[0062] In this embodiment, the three rollers 4 are evenly spaced around the lead screw 1 in the circumferential direction, that is, the included angle between adjacent rollers 4 is 120°. In this embodiment, there are three engagement sections 22 and two transition sections 23. The length of each transition section 23 is... .

[0063] Of course, in other embodiments, the rollers 4 can be arranged in a non-uniform manner, and the included angle between adjacent rollers 4 determines the length of the transition segment 23.

[0064] Furthermore, since only three rollers 4 are needed to achieve normal movement of the planetary roller screw, if the planetary roller screw is initially designed with four rollers 4, in the actual assembly process, at least three rollers 4 only need to be installed at the assembly positions of the four rollers 4 to achieve normal operation.

[0065] Example 2:

[0066] The difference from Example 1 is that, as Figures 7 to 9 As shown ( Figure 7 To clearly see the internal structure, nut 2 is shown in cross-section (the actual nut 2 is a closed structure). In this embodiment, the lead screw 1 has two ends, and its outer wall has two parallel spiral lines.

[0067] Of the multiple rollers 4, two are reference rollers 41. The number of reference rollers 41 is the same as the number of leads in the screw 1. The two reference rollers 41 are centrally symmetrically arranged and correspond to the same meshing section 22. The area between adjacent reference rollers 41 is a reference region. In this embodiment, there are two reference regions. Since at least three rollers 4 are required to achieve normal movement of the planetary roller screw, at least one additional roller 4 is needed in the reference region. This roller 4 can be set at any angle within the reference region. In this embodiment, each reference region is provided with one non-reference roller 41, called a secondary roller 42. The four rollers 4 are evenly distributed circumferentially around the screw 1. Within each reference region, the included angle between two adjacent rollers 4 is 90°.

[0068] The length of transition segment 23 is , In the formula: n is the number of lead screws, that is, the length of the transition section 23 in this embodiment. .

[0069] Of course, the added roller 4 can be at other angles, and the length of the corresponding transition segment 23 will also change.

[0070] In this embodiment, the minimum lead of the planetary roller screw is twice the pitch of the helix, that is, the minimum lead = the number of screw threads multiplied by the pitch of the screw helix.

[0071] Since the angle between the auxiliary roller 42 and the reference roller 41 is 90° in each reference area, the distance between the transition segment 23 between the engagement segment 22 corresponding to the auxiliary roller 42 and the engagement segment 22 corresponding to the reference roller 41 in each reference area is relatively opposite. The transmission segment 43 of the two reference rollers 41 corresponds to the same engagement segment 22. Therefore, the two auxiliary rollers 42 also correspond to the same engagement segment 22. In this embodiment, there are two engagement segments 22 and one transition segment 23.

[0072] Since the normal movement of the planetary roller screw can be achieved by only having three solid rollers 4, the minimum requirement during assembly is simply to assemble the three rollers 4 in the corresponding positions. Therefore, to simplify assembly, this embodiment can retain one reference roller 41 and two auxiliary rollers 42, or retain two reference rollers 41 and one auxiliary roller 42.

[0073] Example 3:

[0074] like Figures 10 to 12 As shown ( Figure 10 To make the internal structure clearer, nut 2 was cut in half (the actual nut 2 is a closed structure). The lead screw 1 has three heads, and the outer wall of the lead screw 1 has three parallel spiral lines.

[0075] Since the number of leadscrew 1 is three, in this embodiment, the number of reference rollers 41 is three. The three reference rollers 41 are evenly distributed around the leadcrew 1 to form three reference areas. A secondary roller 42 can be set at any position in each reference area. In this embodiment, one secondary roller 42 is set in each of the three reference areas. The six rollers 4 are evenly distributed around the leadcrew 1, and the included angle between adjacent rollers 4 is 60°.

[0076] In the formula: n is the number of lead screws, that is, the length of the transition section 23 in this embodiment. Of course, the added roller 4 can be at other angles, and the length of the corresponding transition segment 23 will also change. In this embodiment, the minimum lead of the planetary roller screw is 3 times the pitch of the helix, that is, minimum lead = number of screw 1 threads multiplied by the pitch of the screw 1 helix.

[0077] Since the angle between the auxiliary roller 42 and the reference roller 41 is 60° in each reference area, the distance between the transition section 23 between the engagement section 22 of the auxiliary roller 42 and the engagement section 22 of the reference roller 41 in each reference area is relatively opposite. The transmission section 43 of the two reference rollers 41 corresponds to the same engagement section 22. Therefore, the two auxiliary rollers 42 also correspond to the same engagement section 22. In this embodiment, there are two engagement sections 22 and one transition section 23.

[0078] Since only three rollers 4 are needed to achieve normal movement of the planetary roller screw, the minimum requirement during assembly is simply to assemble three rollers 4 in the corresponding positions. Therefore, to simplify assembly, any three rollers 4 can be retained in this embodiment.

[0079] In this embodiment, the number of reference rollers 41 is sufficient to meet the minimum number of rollers 4 in the structural design. Therefore, in this embodiment, auxiliary rollers 42 are not required. However, from the perspective of load capacity, the more rollers 4 there are, the greater the load. Therefore, when the lead screw 1 has three heads, it is preferable to evenly distribute six rollers 4.

[0080] In other embodiments, the auxiliary rollers 42 in each reference region can be randomly arranged. The engagement segment 22 opposite to the transmission segment 43 on the reference roller 41 is the reference segment. In each reference region, taking the reference segment as the 0th engagement segment 22, the length of the transition segment 23 between the i-th engagement segment 22 and the (i-1)-th engagement segment 22 along the axial direction of the nut 2 is... Where n is the number of leads in lead screw 1, n = 1, 2, 3, 4, 5..., and M is the pitch of lead screw 1. Let k be the angle between the roller 4 corresponding to the k-th engagement segment 22 and a reference roller 41 at the end of its design interval, where k = i or i-1, i is a positive integer, and the reference roller 41 is considered as the 0th roller 4. It is 0 degrees.

[0081] The present invention generates axial rigid constraint on the roller 4 through the mutual meshing between the second ring tooth and the first ring groove 21 on the transmission section 43; through the design of the jump section 23, the correct meshing between the roller 4 and the nut 2 and the lead screw 1 is realized, the planetary motion of the roller 4 revolving and rotating between the lead screw 1 and the nut 2 is realized, and the relative sliding between the lead screw 1 and the nut 2 is realized.

[0082] Compared to traditional standard planetary roller screws, the annular groove structure eliminates the complex design of gears and threads, resulting in a simpler overall structure and significantly reducing the machining difficulty of planetary roller screws. Simultaneously, the annular groove structure offers easier precision control, making it suitable for large-scale, low-cost, and high-precision production. Furthermore, the simplified structure employing retaining rings at both ends of the planetary carrier 3 and stepped surfaces of the rollers 4 effectively restricts the axial and radial movement of the rollers 4, ensuring smooth transmission and guaranteeing the reliability of the transmission mechanism. This solution enables even a conventional single-start screw to achieve a stable layout of at least three rollers 4 with precise feed performance, providing a simplified, cost-effective, and high-performance solution for applications requiring non-self-locking, constant lead, and small lead movement.

[0083] Based on the above-described preferred embodiments of the present invention, and through the foregoing description, those skilled in the art can make various changes and modifications without departing from the inventive concept. The technical scope of this invention is not limited to the contents of the specification, but must be determined according to the scope of the claims.

Claims

1. A standard multi-segment annular groove planetary roller screw, characterized in that, include: Lead screw (1), and Nut (2), the nut (2) is sleeved on the lead screw (1), and the inner sidewall of the nut (2) is provided with a plurality of engagement sections (22) and transition sections (23) located between adjacent engagement sections (22) along its axial direction; Multiple rollers (4) are mounted on the inside of the nut (2) via a planetary carrier (3) and cooperate with the lead screw (1) and the engagement section (22) to realize the relative movement between the nut (2) and the lead screw (1). The rollers (4) are rotatably connected to the planetary carrier (3). The number of rollers (4) is at least 3. The multiple rollers (4) are circumferentially arranged on the inside of the nut (2). Each roller (4) is provided with a transmission section (43). In this section, one of the transmission sections (43) is opposite to one engagement section (22), each engagement section (22) includes a plurality of first annular grooves (21) spaced apart along the axial direction of the nut (2), and the transmission section (43) includes a plurality of second annular grooves (45) spaced apart along the axial direction of the roller (4). The distance d1 between adjacent first annular grooves (21), the distance d2 between adjacent second annular grooves (45) and the pitch M of the thread on the lead screw (1) are all equal. When the number of threads in the lead screw (1) is 1, there is a reference roller (41) among the multiple rollers (4), and the length of the transition segment (23) between the i-th engagement segment (22) and the (i-1)-th engagement segment (22) is... In the formula, M is the angle between the two adjacent rollers (4) corresponding to the i-th engagement segment (22) and the (i-1)-th engagement segment (22), and M is the pitch of the screw (1) helix. When the number of heads of the lead screw (1) is n, and n is a positive integer greater than 1, there are n reference rollers (41) among the multiple rollers (4), and the n reference rollers (41) are arranged in a centrally symmetrical manner, with the reference area between adjacent reference rollers (41); In each of the aforementioned reference regions, the length of the transition segment (23) between the i-th occlusal segment (22) and the (i-1)-th occlusal segment (22) = ,in, Let k be the angle between the roller (4) corresponding to the k-th engagement segment (22) and a reference roller (41) at the end of its design interval, where k = i or i-1; the reference roller (41) is considered as the 0th roller (4). The degree is 0 degrees; multiple reference rollers (41) are opposite to the same engagement segment (22).

2. The standard multi-segment annular groove planetary roller screw according to claim 1, characterized in that: Multiple rollers (4) are evenly distributed around the screw (1) in the circumferential direction.

3. The standard multi-segment annular groove planetary roller screw according to claim 1, characterized in that: The number of second annular grooves (45) on each of the transmission segments (43) is less than or equal to the number of first annular grooves (21) in the corresponding engagement segment (22), and the number of second annular grooves (45) on each of the transmission segments (43) is greater than or equal to one.

4. The standard multi-segment annular groove planetary roller screw according to claim 1, characterized in that: The transmission section (43) forms a second ring tooth through a second ring groove (45), and the tooth surface of the second ring tooth is a convex arc surface.

5. The standard multi-segment annular groove planetary roller screw according to claim 1, characterized in that: The nut (2) is provided with a limiting member (5), which is used to limit the axial sliding of the planet carrier (3).

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