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CN-121977055-A - Reverse planetary roller screw mechanism with planetary rollers arranged on nut

CN121977055ACN 121977055 ACN121977055 ACN 121977055ACN-121977055-A

Abstract

The invention belongs to the technical field of mechanical transmission, and discloses a reverse planetary roller screw mechanism with planetary rollers arranged on nuts. The mechanism comprises a screw rod, a nut and a plurality of planetary rollers, wherein the planetary rollers are rotatably and radially arranged on the circumferential wall of the nut and axially distributed along the circumferential wall. Inner gear rings are arranged on the inner sides of the two ends of the nut, and the two ends of the planetary roller are supported by the retainer and axially positioned by the snap springs. The outer surface of the screw rod is provided with a first spiral tooth meshed with a second spiral tooth on the planetary roller, and the end part of the planetary roller is provided with a second transmission tooth meshed with the first transmission tooth on the inner gear ring, so that the conversion of the rotary motion between the screw rod and the nut is realized. The planetary roller is internally arranged, so that the nut structure is simplified, the precise machining of the full-length internal thread is avoided, and the manufacturing difficulty and cost are remarkably reduced. By increasing the number of planetary rollers, the bearing capacity and rigidity are improved.

Inventors

  • LI BAOMIN

Assignees

  • 山东立沃数控科技有限责任公司

Dates

Publication Date
20260505
Application Date
20260305

Claims (7)

  1. 1. The reverse planetary roller screw mechanism with planetary rollers arranged on a nut comprises a screw, the nut and a plurality of planetary rollers, and is characterized in that the planetary rollers are rotatably and radially arranged on the circumferential wall of the nut, the planetary rollers are distributed along the axial direction of the nut, and a containing cavity for containing the screw is formed in the nut; And transmission pieces meshed with each other are respectively arranged between the screw rod and the planetary roller and between the planetary roller and the nut, so that the rotation movement of the screw rod and the rotation movement of the nut can be converted through the rotation of the planetary roller.
  2. 2. A reverse planetary roller screw mechanism in which planetary rollers are mounted to a nut as claimed in claim 1, wherein both ends of a plurality of said planetary rollers are rotatably supported on a circumferential wall of said nut by means of a cage.
  3. 3. A reverse planetary roller screw mechanism with planetary rollers mounted to a nut according to claim 2, wherein the cage is axially positioned on the nut by a snap spring.
  4. 4. A reverse planetary roller screw mechanism in which planetary rollers are mounted on a nut according to claim 3, wherein inner sides of two ends of the nut are provided with inner gear rings, the ends of the planetary rollers are meshed with the inner gear rings, the inner gear rings are arranged between the nut and the retainer, the inner gear rings are provided with clamping grooves, and the clamping springs are clamped in the clamping grooves of the inner gear rings.
  5. 5. The reverse planetary roller screw mechanism of claim 4, wherein the driving member comprises a first screw tooth provided on an outer surface of the screw, a second screw tooth provided on an outer surface of the planetary roller and engaged with the first screw tooth, a first driving tooth provided on an inner diameter of the ring gear, and a second driving tooth provided at both ends of the planetary roller and engaged with the first driving tooth.
  6. 6. The reverse planetary roller screw mechanism of claim 4, wherein the inner side of the nut is provided with female screw sections at both ends in an axial direction, and the female screw sections of the nut are connected with the ring gear.
  7. 7. The reverse planetary roller screw mechanism in which planetary rollers are mounted to a nut as claimed in claim 4, wherein both ends of the nut are further provided with sealing members, the sealing members are disposed outside the ring gear, and the sealing members are disposed inside the nut.

Description

Reverse planetary roller screw mechanism with planetary rollers arranged on nut Technical Field The invention belongs to the technical field of mechanical transmission, and particularly relates to a reverse planetary roller screw mechanism with planetary rollers arranged on a nut. Background The planetary roller screw pair is used as a high-precision, high-rigidity and high-bearing transmission device for converting rotary motion into linear motion, has performances far exceeding those of the ball screw pair, and has been rapidly developed and widely applied in the field of manufacturing high-end equipment such as aerospace, industrial robots, high-end machine tools, new energy automobiles, medical appliances and the like in recent years. At present, the planetary roller screw pair mainly comprises main structural types such as standard type, reverse type, circulating type, differential type and the like. The reverse planetary roller screw is usually provided with a plurality of planetary rollers on the screw, the nut is an integral long sleeve, and the inner wall of the nut is required to be precisely ground and machined into inner spiral teeth meshed with the planetary rollers along the whole length, namely full-length inner threads. During operation, the screw rod is driven to do linear motion through meshing transmission of the planetary rollers by rotating the nut. However, the existing structure has the remarkable defects that firstly, the nut serving as a sleeve member is extremely difficult to precisely grind the inner spiral teeth with long stroke and large length-diameter ratio on the whole inner wall, the machining efficiency is low and the manufacturing cost is high due to extremely high requirements on a machine tool, a grinding head, a grinding wheel and a process, and secondly, the grinding difficulty of the inner threads of the long nut is increased along with the increase of the length, deformation and precision errors are easy to generate, so that the increase of the axial length, namely the bearing length of the nut is severely limited, and the length-diameter ratio of the nut is difficult to be large. In practical applications, if the working stroke needs to be increased, the inner diameter of the nut often has to be increased, which not only increases the space occupation of the transmission component, but also is contrary to the requirements of many devices for pursuing compact structure and large working range. Therefore, how to design a planetary roller screw mechanism with high bearing capacity, high efficiency and low cost manufacture is a technical problem to be solved in the field. To this end, the present invention provides a reverse planetary roller screw mechanism in which planetary rollers are mounted to a nut. Disclosure of Invention In view of the above problems in the prior art, an object of the present invention is to provide a reverse planetary roller screw mechanism in which planetary rollers are mounted on a nut, wherein the planetary rollers are built in the nut, so that the structure is simplified, the processing difficulty and cost are reduced, and the bearing capacity and rigidity are improved. The aim of the invention can be achieved by the following technical scheme: the reverse planetary roller screw mechanism with planetary rollers arranged on a nut comprises a screw, the nut and a plurality of planetary rollers, wherein the planetary rollers are rotatably and radially arranged on the circumferential wall of the nut, the planetary rollers are distributed along the axial direction of the nut, and a containing cavity for containing the screw is formed in the nut; And transmission pieces meshed with each other are respectively arranged between the screw rod and the planetary roller and between the planetary roller and the nut, so that the rotation movement of the screw rod and the rotation movement of the nut can be converted through the rotation of the planetary roller. As a further preferable embodiment of the present invention, both ends of the plurality of planetary rollers are rotatably supported on the circumferential wall of the nut by a cage. As a further preferred embodiment of the present invention, the retainer is axially positioned on the nut by means of a snap spring. As a further preferable technical scheme of the invention, inner sides of two ends of the nut are provided with annular gears, the end parts of the planetary rollers are meshed with the annular gears, the annular gears are arranged between the nut and the retainer, the annular gears are provided with clamping grooves, and the clamping springs are clamped in the clamping grooves of the annular gears. As a further preferable technical scheme of the invention, the transmission member comprises a first spiral tooth arranged on the outer surface of the screw rod, a second spiral tooth arranged on the outer surface of the planetary roller and meshed with the first spiral tooth, a first transmi