Planetary roller screw pair

Abstract

The utility model discloses a planetary roller lead screw pair, which comprises a lead screw, a retainer and a roller, the center of the retainer is provided with a through mounting hole, the lead screw is provided with a lead screw gear part and a lead screw thread part, and the roller is correspondingly provided with a roller gear part and a roller thread part. The screw is characterized in that the screw gear part and the screw thread part are arranged in a spaced mode, an annular concave sleeving installation part is arranged between the screw gear part and the screw thread part, the roller gear part and the roller thread part are arranged in a spaced mode, and the roller gear part and the roller thread part are annular concave rotating installation parts. Arc-shaped clamping grooves are formed in the end faces of the outer sides of the retainers in an inward concave mode, the retainers are arranged on the sleeving installation parts in a sleeving mode through the installation holes, the lead screw gear parts and the lead screw thread parts limit installation of the retainers, and the rotary installation parts on the pin rollers are installed in the corresponding arc-shaped clamping grooves in a rotatable and embedded mode. The utility model has the advantages of simple structure, few parts, low cost and higher assembly efficiency.

Description

Technical Field

[0001] This utility model relates to the field of precision lead screw technology, and in particular to a planetary roller lead screw pair. Background Technology

[0002] Planetary roller screw assemblies are high-precision, high-load transmission devices that convert rotary motion into linear motion. While complex in structure, they offer superior performance and are widely used in demanding fields such as aerospace, military, and machine tools. Currently, existing planetary roller screw assemblies mainly consist of a screw, nut, rollers, and cage. The cage (also called a retainer or isolator) is a key component, its main function being to fix and guide the movement of the rollers, ensuring that the rollers are evenly distributed and roll orderly between the screw and nut. Conventional planetary roller screw assemblies of this type typically have two cages for the rotatable mounting of the rollers at both ends. The cages are usually fitted onto the screw through a centrally located mounting hole, and a retaining circlip is installed on the screw to limit the cage's position. This structure involves many parts and assembly steps, resulting in lower assembly efficiency and higher manufacturing costs. Summary of the Invention

[0003] The technical problem to be solved by this utility model is to provide a planetary roller screw pair with simple structure, few parts and high assembly efficiency.

[0004] The technical solution adopted by this utility model to solve the above-mentioned technical problems is as follows:

[0005] A planetary roller screw assembly includes a screw, a cage, and multiple rollers that mate with the screw. The cage has a through mounting hole at its center. The screw has a gear portion and a threaded portion. Each roller has a corresponding gear portion for meshing with the gear portion and a threaded portion for meshing with the threaded portion. The gear portion and the threaded portion are spaced apart, and a ring-shaped recessed fitting is formed between them. The roller gear portion and the roller thread portion are spaced apart. The roller gear portion and the roller thread portion are annular recessed rotating mounting portions. The outer end face of the cage is provided with multiple arc-shaped grooves that match the number of rollers and the assembly position. The cage is sleeved on the sleeve mounting portion through the mounting hole. The lead screw gear portion and the lead screw thread portion limit the installation of the cage. The rotating mounting portion on the roller can be rotatably embedded in the corresponding arc-shaped groove.

[0006] The retainer is made of a material that can undergo elastic deformation, and the retainer is provided with an opening slot that communicates with the mounting hole.

[0007] Multiple arc-shaped slots are evenly spaced around the central axis of the cage.

[0008] The rotating mounting part is a smooth rod, and the shape of the arc-shaped groove matches the rotating mounting part. The opening width of the arc-shaped groove is smaller than the outer diameter of the rotating mounting part.

[0009] The inner diameter of the mounting hole is larger than the outer diameter of the sleeve mounting part, the inner diameter of the mounting hole is smaller than the diameter of the tooth top ring of the lead screw gear part, and the inner diameter of the mounting hole is smaller than the major diameter of the lead screw thread part.

[0010] It also includes a nut, and the lead screw, cage and roller are disposed inside the nut, and the nut and the roller are connected by meshing transmission.

[0011] Compared with the prior art, the advantages of this utility model are:

[0012] (1) Simplified structure and reduced parts: By setting the lead screw gear part and the lead screw thread part at intervals, a sleeve mounting part for cage sleeve installation is formed between the two. After the cage is sleeved and installed, the lead screw gear part and the lead screw thread part form an installation limit for the cage, eliminating the auxiliary limiting parts such as snap rings in the traditional structure, reducing the number of parts used and reducing the structural complexity.

[0013] (2) Improved assembly efficiency: No additional auxiliary limiting parts such as snap rings are required, which simplifies the assembly steps. The rollers are embedded in the arc-shaped slots of the cage through the rotating mounting part, which realizes quick positioning and rotation support, reducing the cumbersome matching process between the rollers and the cage in traditional assembly.

[0014] (3) Reduced manufacturing costs: The reduction in parts directly reduces material costs and processing time (such as the processing and installation of snap rings); the cage utilizes the screw's own structure for limiting movement, reducing the need for high-precision mating surfaces;

[0015] (4) Space utilization optimization: The ring-shaped recessed socket and rotating mounting parts achieve a compact structure, making them more suitable for fields with stringent space requirements (such as aerospace equipment). Attached Figure Description

[0016] Figure 1 This is a partial cross-sectional view of the present invention.

[0017] Figure 2 This is a three-dimensional structural diagram of the present invention with the nut removed;

[0018] Figure 3 This is a cross-sectional view of the cage and lead screw in this utility model.

[0019] Figure 4 This is a three-dimensional structural diagram of the cage in this utility model. Detailed Implementation

[0020] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0021] As shown in the figure, a planetary roller screw assembly includes a screw 1, a cage 2, and multiple rollers 3 that cooperate with the screw 1. The cage 2 has a through mounting hole 21 at its center. The screw 1 has a screw gear portion 11 and a screw thread portion 12. The rollers 3 are correspondingly provided with roller gear portions 31 for meshing with the screw gear portion 11 and roller thread portions 32 for meshing with the screw thread portions 12. The screw gear portions 11 and screw thread portions 12 are spaced apart, and the screw gear portions 11 and screw thread portions 12 are connected by an annular recessed sleeve. Mounting part 13, corresponding to roller gear part 31 and roller thread part 32 are spaced apart, roller gear part 31 and roller thread part 32 are annular recessed rotating mounting parts 33, the outer end face of the retainer 2 is provided with multiple arc-shaped grooves 22 that match the number and assembly position of rollers 3, the retainer 2 is sleeved on the sleeve mounting part 13 through mounting hole 21, the lead screw gear part 11 and lead screw thread part 12 limit the installation of retainer 2, the rotating mounting part 33 on roller 3 can be rotatably embedded in the corresponding arc-shaped groove 22.

[0022] In this specific embodiment, the retainer 2 is made of a material capable of elastic deformation, and the retainer 2 is provided with an opening slot 23 that communicates with the mounting hole 21. The design of the opening slot 23, combined with the elastic deformation material used in the retainer 2, facilitates faster installation and disassembly between the retainer 2 and the lead screw 1. During installation, an external force is applied to appropriately pry open the retainer 2, making the mounting hole 21 slightly larger, allowing the lead screw gear portion 11 on the lead screw 1 to pass through, so that the retainer 2 is fitted into the sleeve mounting portion 13. After the external force is removed, the retainer 2 returns to its original shape, and the lead screw gear portion 11 and the lead screw thread portion 12 form an installation limit for the retainer 2.

[0023] In this specific embodiment, in order to cooperate with the installation of the roller 3, multiple arc-shaped slots 22 are evenly distributed and spaced around the central axis of the retainer 2.

[0024] In this specific embodiment, the rotating mounting part 33 is a smooth rod, and the shape of the arc-shaped groove 22 matches the rotating mounting part 33. The opening width of the arc-shaped groove 22 is smaller than the outer diameter of the rotating mounting part 33. Self-locking is achieved by utilizing the elasticity of the material to improve the stability of the assembly.

[0025] In this specific embodiment, the inner diameter of the mounting hole 21 is larger than the outer diameter of the sleeve mounting part 13, the inner diameter of the mounting hole 21 is smaller than the diameter of the tooth ring of the lead screw gear part 11, and the inner diameter of the mounting hole 21 is smaller than the major diameter of the lead screw thread part 12. This facilitates the limiting effect of the lead screw gear part 11 and the lead screw thread part 12 on the installation of the cage 2 after installation.

[0026] In this specific embodiment, a nut 4 is also included. The lead screw 1, cage 2, and roller 3 are disposed inside the nut 4, and the nut 4 and roller 3 are connected by meshing transmission. This constitutes a complete planetary roller lead screw pair.

[0027] In this specific embodiment, in order to ensure the stable installation of the roller 3, two retainers 2 are used, and the two retainers 2 are spaced apart. Then, the corresponding lead screw 1 is provided with two lead screw gear parts 11, and a lead screw thread part 12 is provided between the two lead screw gear parts 11. The corresponding roller 3 is provided with two roller gear parts 31, and a roller thread part 32 is provided between the two roller gear parts 31.

Claims

1. A planetary roller screw assembly, comprising a screw, a cage, and a plurality of rollers cooperating with the screw, wherein the cage has a through mounting hole at its center, the screw has a screw gear portion and a screw thread portion, and the rollers are correspondingly provided with roller gear portions for meshing with the screw gear portion and roller thread portions for meshing with the screw thread portion, characterized in that... The lead screw gear portion and the lead screw thread portion are spaced apart, and there is an annular recessed sleeve mounting portion between the lead screw gear portion and the lead screw thread portion. Correspondingly, the roller gear portion and the roller thread portion are spaced apart, and there is an annular recessed rotating mounting portion between the roller gear portion and the roller thread portion. The outer end face of the cage is provided with multiple arc-shaped grooves that are recessed inward and match the number and assembly position of the rollers. The cage is sleeved on the sleeve mounting portion through the mounting hole. The lead screw gear portion and the lead screw thread portion limit the installation of the cage. The rotating mounting portion on the roller can be rotatably embedded in the corresponding arc-shaped groove.

2. A planetary roller screw assembly as described in claim 1, characterized in that... The retainer is made of a material that can undergo elastic deformation, and the retainer is provided with an opening slot that communicates with the mounting hole.

3. A planetary roller screw assembly as described in claim 1, characterized in that... Multiple arc-shaped slots are evenly spaced around the central axis of the cage.

4. A planetary roller screw assembly as described in claim 1, characterized in that... The rotating mounting part is a smooth rod, and the shape of the arc-shaped groove matches the rotating mounting part. The opening width of the arc-shaped groove is smaller than the outer diameter of the rotating mounting part.

5. A planetary roller screw assembly as described in claim 1, characterized in that... The inner diameter of the mounting hole is larger than the outer diameter of the sleeve mounting part, the inner diameter of the mounting hole is smaller than the diameter of the tooth top ring of the lead screw gear part, and the inner diameter of the mounting hole is smaller than the major diameter of the lead screw thread part.

6. A planetary roller screw assembly as described in claim 1, characterized in that... It also includes a nut, and the lead screw, cage and roller are disposed inside the nut, and the nut and the roller are connected by meshing transmission.

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