Retainer of planetary roller screw pair

Abstract

The utility model discloses a retainer of a planetary roller lead screw pair, which comprises a retainer body, the center of the retainer body is provided with a through accommodating cavity for a lead screw to pass through for installation, and the retainer is characterized in that the retainer body is made of a non-metal material with high strength, high rigidity and light weight, and a plurality of elastic buffer parts are arranged in the accommodating cavity at intervals in a protruding manner. The retainer has the advantages of low cost and light weight, and the operation stability and the service life of the planetary roller screw pair can be ensured when the retainer is applied to the corresponding planetary roller screw pair.

Description

Technical Field

[0001] This utility model relates to a cage, and more particularly to a cage for a planetary roller screw pair. Background Technology

[0002] In planetary roller screw assemblies, the cage (also known as a retainer or isolator) is a key component. Its main function is to fix and guide the movement of the rollers, ensuring that the rollers are evenly distributed and roll orderly between the screw and nut. Due to the continuous improvement in the load-bearing capacity and precision requirements of planetary roller screw assemblies as industrial technology advances, metal cages are widely used in planetary ball screw assemblies. The currently used metal cages have the following problems: 1. The metal cage is relatively heavy, which increases the overall weight of the planetary roller screw pair. This may not be suitable for applications with strict weight restrictions. 2. The cost of metal materials is relatively high, and the processing technology is relatively complex, resulting in a high manufacturing cost for the cage. 3. Under long-term cyclic loads, the metal cage may experience metal fatigue, which will affect its performance and reliability. 4. The metal cage has a central cavity through which the screw passes for installation. The metal cage is fitted onto the screw through this cavity. During actual use, impacts and vibrations will occur, resulting in rigid collisions between the screw and the metal cage. This will lead to greater wear and damage between the two, which is detrimental to the operational stability and service life of the planetary roller screw pair, and will also cause significant abnormal noise. Summary of the Invention

[0003] The technical problem to be solved by this utility model is to provide a low-cost and lightweight cage for planetary roller screw pairs. Applying this cage to the corresponding planetary roller screw pairs can ensure the operational stability and service life of the planetary roller screw pairs.

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

[0005] A cage for a planetary roller screw assembly includes a cage body with a through cavity at the center for the screw to pass through and be mounted. The cage body is made of a non-metallic material with high strength, high rigidity, and light weight. The cavity has multiple elastic buffer portions with spaced protrusions.

[0006] The cage body is made of polymethyl methacrylate.

[0007] The cage body and the elastic buffer part are integrally formed.

[0008] The protruding end face of the elastic buffer part is an arc-shaped end face that bulges inward from the middle.

[0009] The cage body is made of a non-metallic material that can undergo elastic deformation, and the cage body is provided with an opening groove that communicates with the receiving cavity.

[0010] The outer end face of the cage body is provided with multiple inwardly recessed arc-shaped slots for the corresponding smooth rod portions on the rollers to be embedded and installed. The multiple arc-shaped slots are evenly distributed and spaced around the central axis of the cage body.

[0011] The arc-shaped groove mates with the corresponding smooth rod portion on the roller, and the opening width of the arc-shaped groove is smaller than the outer diameter of the corresponding smooth rod portion.

[0012] The multiple elastic buffer sections are evenly distributed.

[0013] Compared with the prior art, the advantages of this utility model are:

[0014] (1) The cage body is made of non-metallic materials with high strength, high rigidity and light weight, which has a low cost. Under the premise of meeting the strength and rigidity, it achieves lightweight design, which is suitable for use in weight-sensitive application scenarios. At the same time, the lightweight design can also reduce motion inertia. When applied to planetary ball screw pairs, it can improve the dynamic response performance of planetary ball screw pairs.

[0015] (2) Multiple elastic buffer parts are provided in the cavity. The elastic buffer parts can be used to absorb vibration and impact, reduce hard impact and wear between the screw and the cage, effectively improve the running stability and service life of the planetary roller screw pair, and reduce noise (abnormal noise).

[0016] (3) In addition, recesses are formed between adjacent elastic buffers, and these recesses can form lubrication channels with the lead screw to achieve full lubrication of the mechanism. Attached Figure Description

[0017] Figure 1 This is a three-dimensional structural diagram of the present invention;

[0018] Figure 2 This is a three-dimensional structural diagram of the part of the present invention applied to the entire planetary ball screw assembly;

[0019] Figure 3 This is a three-dimensional structural diagram of the part of the present invention that is installed in conjunction with a lead screw. 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 cage for a planetary roller screw pair includes a cage body 1. The center of the cage body 1 is provided with a through cavity 11 through which the screw 2 is installed. The cage body 1 is made of a non-metallic material with high strength, high rigidity and light weight. Multiple elastic buffer parts 12 are provided in the cavity 11 with spaced protrusions.

[0022] In this specific embodiment, the cage body 1 is made of polyetheretherketone (PEEK). PEEK is a high-performance specialty engineering plastic with excellent mechanical properties and lightweight characteristics, as well as superior wear resistance and self-lubricating properties. Using this material to make the cage body 1 ensures its high strength, high rigidity, and light weight. Furthermore, the material has a low coefficient of friction (0.3-0.4), and combined with its self-lubricating properties, when assembled with the lead screw 2 in the planetary ball screw assembly, it reduces wear on the contact surface of the lead screw 2, thereby extending its service life. Testing has shown that this type of cage reduces the wear rate by 30% compared to traditional cages at high speeds.

[0023] In this specific embodiment, the cage body 1 and the elastic buffer part 12 are integrally formed. This allows for one-time injection molding, reducing machining steps and lowering overall costs.

[0024] In this specific embodiment, the protruding end face 121 of the elastic buffer portion 12 is an arc-shaped end face that protrudes inward from the middle. This reduces the contact area with the roller 2 and decreases wear.

[0025] In this specific embodiment, the cage body 1 is made of a non-metallic material capable of elastic deformation, and the cage body 1 is provided with an opening groove 13 that communicates with the receiving cavity 11. The design of the opening groove 13, combined with the elastically deformable material used in the cage body 1, facilitates faster installation and disassembly between the cage and the lead screw 2. This structure is suitable for the lead screw 2 to have a corresponding recessed mounting part for installing the cage. The front and rear parts of the recessed mounting part can limit the cage, eliminating the need for additional limiting springs. During installation, by applying external force, the cage body is appropriately pried open, making the receiving cavity 11 slightly larger, passing through the limiting part on the lead screw 2, and locking into the recessed mounting part. After the external force is removed, the cage body 1 returns to its original shape.

[0026] In this specific embodiment, a plurality of arc-shaped slots 14 are recessed inward on the outer end face of the cage body 1 for the corresponding smooth rod portions 31 on the rollers 3 to be embedded and installed. The plurality of arc-shaped slots 14 are evenly distributed and spaced around the central axis of the cage body 1. This makes the assembly and disassembly between the cage and the rollers 3 simpler, more convenient and faster, and can effectively guide the movement of the rollers 3.

[0027] In this specific embodiment, the arc-shaped groove 14 engages with the corresponding smooth rod portion 31 on the screw 3, and the opening width of the arc-shaped groove 14 is smaller than the outer diameter of the corresponding smooth rod portion 31. Self-locking is achieved using the elasticity of the material to improve assembly stability.

[0028] In this specific embodiment, multiple elastic buffer sections 12 are evenly distributed to achieve uniform force distribution and load bearing.

[0029] In this specific embodiment, the recessed portion 15 formed between adjacent elastic buffer portions 12 constitutes a lubrication channel after the overall assembly is completed, so as to ensure sufficient lubrication of the contact area between the roller and the lead screw and nut.

Claims

1. A cage of a planetary roller screw pair comprising a cage body, a through-going accommodating cavity for mounting a screw is provided in the center of the cage body, characterized in that The cage body is made of non-metallic material, and the interval protrusions in the accommodating cavity are provided with a plurality of elastic buffer portions.

2. Cage for a planetary roller screw pair according to claim 1, characterized in that The cage body is made of polyoxymethylene.

3. Cage for a planetary roller screw pair according to claim 1, characterized in that The cage body is integrally formed with the elastic buffer portions.

4. Cage for a planetary roller screw pair according to claim 1, characterized in that The protruding end surface of the elastic buffer portion is an arc-shaped end surface which is inwardly protruding in the middle.

5. Cage for a planetary roller screw pair according to claim 1, characterized in that The cage body is made of non-metallic material which can be elastically deformed, and the cage body is provided with an open slot which is in communication with the accommodating cavity.

6. A cage for a planetary roller screw assembly as claimed in claim 1, characterized in that The outer side end surface of the cage body is inwardly recessed and provided with a plurality of arc-shaped clamping slots for embedding and mounting the corresponding light rod portions of the rollers, and the arc-shaped clamping slots are evenly and spacedly arranged around the central axis of the cage body.

7. Cage for a planetary roller screw according to claim 6, characterized in that The arc-shaped clamping slots are matched with the corresponding light rod portions of the rollers, and the opening width of the arc-shaped clamping slots is smaller than the outer diameter of the corresponding light rod portions.

8. Cage for a planetary roller screw according to claim 1, characterized in that The plurality of elastic buffer portions are evenly arranged.

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