Search

CN-121993559-A - Miniature planetary roller screw device

CN121993559ACN 121993559 ACN121993559 ACN 121993559ACN-121993559-A

Abstract

The invention discloses a miniature planetary roller screw device, and belongs to the technical field of precise transmission. The device comprises a miniature planetary screw rod, a miniature planetary nut sleeved on the screw rod and a transmission assembly arranged in the nut, wherein the transmission assembly consists of a plurality of miniature planetary rollers, a retainer with a circumferential slot and two cam press covers, the retainer is used for accommodating the rollers, two ends of the retainer are fixed through the press covers, and limit protrusions at the outer edges of the press covers are matched with corresponding grooves in the inner wall of the nut to realize integral assembly and fixation. The threads of the roller are meshed with the threads of the screw rod to form line contact transmission, and the rotary motion of the screw rod is converted into axial linear motion of the nut. The invention has the advantages of compact structure, simple assembly, and obviously improved transmission precision, rigidity and bearing capacity while realizing miniaturization through line contact transmission and integrated design, and is particularly suitable for occasions with severe requirements on space and precision, such as robot finger joints.

Inventors

  • ZHAO YONGHAI

Assignees

  • 江苏国量航空航天科技有限公司

Dates

Publication Date
20260508
Application Date
20260212

Claims (8)

  1. 1. The miniature planetary roller screw device comprises a miniature planetary screw rod (5) and a miniature planetary nut (2) sleeved on the miniature planetary screw rod (5), and is characterized by further comprising a transmission assembly, wherein the transmission assembly comprises a miniature planetary roller (1), a retainer (6) and two cam press covers (3); the retainer (6) is arranged inside the miniature planetary nut (2), and a circle of grooves for accommodating the miniature planetary rollers (1) are formed in the circumferential direction of the retainer; the two cam press covers (3) are respectively arranged at two ends of the retainer (6), limit protrusions are arranged at the outer edges of the two cam press covers and are matched with corresponding grooves on the inner wall of the miniature planetary nut (2), and the transmission assembly is fixedly arranged inside the miniature planetary nut (2); The planetary threads of the miniature planetary roller (1) are meshed with the planetary threads on the miniature planetary screw rod (5), and the rotary motion of the miniature planetary screw rod (5) is converted into the linear motion of the miniature planetary nut (2) along the axial direction of the miniature planetary nut.
  2. 2. The miniature planetary roller screw device according to claim 1, wherein the transmission assembly is integrally installed in the miniature planetary nut (2) and is fixed with the miniature planetary nut (2) by a limit protrusion of the cam gland (3).
  3. 3. The miniature planetary roller screw device according to claim 1 or 2, characterized in that the cage (6) and the cam gland (3) are integrally formed or segmented formed using 3D printing.
  4. 4. A miniature planetary roller screw arrangement according to claim 3, characterized in that the diameter of the miniature planetary roller (1) ranges from 0.9mm to 1.5mm.
  5. 5. The miniature planetary roller screw device according to claim 4, wherein the miniature planetary screw (5), the miniature planetary nut (2) and the miniature planetary roller (1) are subjected to a composite heat treatment process combining thermal refining and high-frequency induction quenching.
  6. 6. The miniature planetary roller screw device according to claim 5, wherein the planetary threads of the miniature planetary screw (5) are machined by a grinding and rolling compound process.
  7. 7. The miniature planetary roller screw device according to claim 1, wherein the device is adapted for use with a humanoid robot finger joint with a transmission error of no more than 0.02mm.
  8. 8. The miniature planetary roller screw arrangement according to claim 1, characterized in that a linear contact transmission is provided between the miniature planetary roller (1) and the miniature planetary screw (5).

Description

Miniature planetary roller screw device Technical Field The invention relates to a miniature planetary roller screw device, and belongs to the field of precise transmission mechanisms. Background The planetary roller screw is used as a precision component for converting rotary motion into linear motion, and is widely applied in the fields of industrial automation, aerospace and the like due to the advantages of high transmission efficiency, high rigidity, long service life and the like. Conventional constructions typically employ balls as the transmission medium. Along with the development of the front-edge fields of robot dexterous hands, miniature precision equipment and the like, more stringent requirements are put forward on the miniaturization, high precision and high reliability of the transmission parts. Currently, a planetary ball screw scheme is mainly adopted for a screw for miniature application in the market. However, in the miniaturization process, the scheme has the inherent defects that firstly, the diameter of the ball is reduced sharply due to the miniaturization of the size, so that the assembly difficulty and cost are greatly increased, the machining of a reverser (used for realizing ball circulation) serving as a key component is extremely difficult, the precision is difficult to ensure, secondly, the ball is in point contact with a screw rod and a nut, so that the contact stress is concentrated, the bearing capacity, the rigidity and the shock resistance of the miniature ball screw rod are insufficient, the stability requirements of high-load and high-precision movement are difficult to meet, and moreover, the friction and abrasion of the point contact are more severe than those of the line contact, so that the service life and the precision retention of the screw rod are influenced. Therefore, there is a need for a transmission designed for miniature application, which can overcome the shortcomings of the existing planetary ball screw in terms of structure, strength, precision and manufacturability while achieving a very small size, and provide a miniature linear transmission solution that is more reliable, more precise and easy to assemble. Disclosure of Invention In order to overcome the defects of the prior art, the invention provides a miniature planetary roller screw device, which has the following technical scheme: The miniature planetary roller screw device comprises a miniature planetary screw rod (5), a miniature planetary nut (2) sleeved on the miniature planetary screw rod (5), and a transmission assembly, wherein the transmission assembly comprises a miniature planetary roller (1), a retainer (6) and two cam press covers (3); the retainer (6) is arranged inside the miniature planetary nut (2), and a circle of grooves for accommodating the miniature planetary rollers (1) are formed in the circumferential direction of the retainer; the two cam press covers (3) are respectively arranged at two ends of the retainer (6), limit protrusions are arranged at the outer edges of the two cam press covers and are matched with corresponding grooves on the inner wall of the miniature planetary nut (2), and the transmission assembly is fixedly arranged inside the miniature planetary nut (2); The planetary threads of the miniature planetary roller (1) are meshed with the planetary threads on the miniature planetary screw rod (5), and the rotary motion of the miniature planetary screw rod (5) is converted into the linear motion of the miniature planetary nut (2) along the axial direction of the miniature planetary nut. The transmission assembly is integrally arranged in the miniature planetary nut (2) and is fixed with the miniature planetary nut (2) through a limiting protrusion of the cam gland (3). The retainer (6) and the cam gland (3) are integrally formed or formed in a segmented mode through 3D printing. The diameter of the miniature planetary roller (1) ranges from 0.9mm to 1.5mm. The miniature planetary screw rod (5), the miniature planetary nut (2) and the miniature planetary roller (1) are subjected to a composite heat treatment process combining quenching and tempering and high-frequency induction quenching. The planetary thread of the miniature planetary screw rod (5) is processed by adopting a grinding and rolling composite process. The device is suitable for finger joints of humanoid robots, and the transmission error is not more than 0.02mm. The miniature planetary roller (1) and the miniature planetary screw rod (5) are in linear contact transmission. The invention has the advantages that: 1. the integrated design of the planetary roller structure, the retainer and the cam gland is adopted, and a reverser which is difficult to process and assemble in the miniature ball screw is eliminated. The cam gland can realize the reliable fixing and axial positioning of the internal transmission assembly through the simple matching of the limiting bulge and the inner wall groove of the