CN-121977054-A - Roller of planetary roller screw pair and planetary roller screw pair

CN121977054ACN 121977054 ACN121977054 ACN 121977054ACN-121977054-A

Abstract

The invention discloses a roller of a planetary roller screw pair and the planetary roller screw pair, wherein the roller comprises a roller body, a threaded section is arranged on the roller body, and is characterized in that at least one threaded parameter of the threaded section continuously changes along the axial direction of the roller body so as to adjust the meshing rigidity of different positions of the roller in the axial direction. The design can actively adjust the contact sequence of each thread tooth, change the rigidity of the shaft section, promote the uniform distribution of load along the axial direction of the roller and among the teeth, so as to improve the bearing capacity and the service life of the planetary roller screw pair.

Inventors

LI LIANJIE
XU CHI
XIAO BIN
ZHANG XIANGYU

Assignees

宁波高悦智能科技有限公司

Dates

Publication Date: 20260505
Application Date: 20260126

Claims (10)

1. The roller of the planetary roller screw pair comprises a roller body, wherein a thread section is arranged on the roller body, and the planetary roller screw pair is characterized in that at least one thread parameter of the thread section continuously changes along the axial direction of the roller body so as to adjust the meshing rigidity of the roller body at different positions along the axial direction.
2. The roller of a planetary roller screw assembly according to claim 1, wherein the thread parameter is a thread pitch, and the thread pitch is gradually changed along an axial direction of the roller body.
3. The roller of the planetary roller screw pair according to claim 2, wherein the gradual trend of the pitch is positively correlated with the theoretical load distribution trend of the planetary roller screw pair on the roller body, and is represented by a larger pitch value at an axial position with a larger theoretical load and a smaller pitch value at an axial position with a smaller theoretical load.
4. A roller of a planetary roller screw assembly according to claim 2 or 3, wherein the pitch is linearly graded or non-linearly graded.
5. A roller of a planetary roller screw assembly according to claim 4, wherein the pitch difference between adjacent threads is in the range of 0.001 mm to 0.002 mm.
6. The roller of a planetary roller screw assembly according to claim 1, wherein the thread parameter is pitch diameter, and the pitch diameter is tapered along the axial direction of the roller body.
7. The roller of a planetary roller screw assembly as claimed in claim 6, wherein the pitch diameter is smaller at an axial position where the theoretical load is larger, and the pitch diameter is larger at an axial position where the theoretical load is smaller.
8. The roller of a planetary roller screw assembly according to claim 6, wherein the taper is in the range of 1:50 to 1:200.
9. The roller of a planetary roller screw assembly according to claim 1, wherein one end of the roller body is provided with a mounting mark for indicating the direction in which the screw thread parameter is continuously changed.
10. A planetary roller screw pair, comprising: the periphery of the screw rod is provided with threads; The nut is sleeved outside the screw rod, and threads are arranged on the inner wall of the nut; A plurality of rollers as claimed in any one of claims 1 to 9 disposed between said screw and said nut, said threaded segments on said roller body respectively engaging corresponding threads on said screw and said nut; at least one cage for separating and guiding said rollers.

Description

Roller of planetary roller screw pair and planetary roller screw pair Technical Field The invention relates to the technical field of mechanical transmission, in particular to a roller of a planetary roller screw pair and the planetary roller screw pair. Background The planetary roller screw pair is used as a high-precision transmission mechanism for converting rotary motion into linear motion, has the advantages of high bearing capacity, high transmission precision, high rigidity and the like, and is widely applied to high-end equipment such as numerical control machine tools, industrial robots, aerospace actuators and the like. In the prior art, the rollers of the planetary roller screw pair generally adopt a uniform thread structure with equal pitch and equal pitch. However, since the rigidity distribution of the screw, nut, and roller itself in the axial direction is not uniform (for example, affected by factors such as shaft end support rigidity, contact deformation, and the like), the load is severely unevenly distributed among the plurality of rollers, and between the different axial sections of the single roller and the respective thread teeth. In general, threads closer to the load input or stiffer region are subject to excessive concentrated loads, while threads farther from the region are less loaded or even do not participate in the load. The uneven load distribution can cause a series of problems of overhigh local contact stress, aggravation of abrasion, reduction of fatigue life and the like, and severely restricts the improvement of the whole bearing capacity and reliability of the screw pair. In order to solve the above problems, the prior art proposes a scheme such as shaping a thread and grooving an optical axis section, but the method is often complex in structure, difficult to process, dependent on complex algorithm in optimal design, and mostly belongs to passive adaptive adjustment, and load homogenization cannot be guided from a root by actively adjusting the axial rigidity distribution of a roller. Disclosure of Invention The invention aims to solve the technical problems of providing a roller of a planetary roller screw pair and the planetary roller screw pair, wherein the rigidity of different shaft sections of the roller can be actively regulated through the design of axial continuous change of roller thread parameters, so that the distribution of load among thread teeth is guided and optimized, and the roller and the planetary roller screw pair are applied to the planetary roller screw pair, so that the integral bearing capacity, transmission precision and service life of the screw pair can be improved. The technical scheme adopted for solving the technical problems is as follows: a roller of a planetary roller screw pair comprises a roller body, wherein a thread section is arranged on the roller body, and at least one thread parameter of the thread section continuously changes along the axial direction of the roller body so as to adjust the meshing rigidity of the roller body at different positions along the axial direction. The thread parameter is thread pitch, and the thread pitch is gradually changed along the axial direction of the roller body. The gradual change trend of the screw pitch is positively correlated with the theoretical load distribution trend of the planetary roller screw pair on the roller body, and the gradual change trend of the screw pitch is expressed in that the screw pitch value is larger at the axial position with larger theoretical load and smaller at the axial position with smaller theoretical load. The pitch is linearly graded or non-linearly graded. The pitch difference of adjacent threads ranges from 0.001 mm to 0.002 mm. The thread parameter is pitch diameter, and the pitch diameter is arranged in a taper manner along the axial direction of the roller body. The pitch diameter is smaller at the axial position with larger theoretical load, and the pitch diameter is larger at the axial position with smaller theoretical load. The taper ranges from 1:50 to 1:200. One end of the roller body is provided with an installation mark for indicating the continuous change direction of the thread parameters. A planetary roller screw pair comprising: the periphery of the screw rod is provided with threads; The nut is sleeved outside the screw rod, and threads are arranged on the inner wall of the nut; a plurality of rollers as described above, disposed between the lead screw and the nut, the thread segments on the roller body respectively engaging corresponding threads on the lead screw and the nut; at least one cage for separating and guiding said rollers. Compared with the prior art, the invention has the advantages that the design ensures that the thread parameters (such as pitch diameter, screw pitch and the like) of the roller continuously change along the axis, realizes the active design and accurate regulation of the axial meshing rigidity distribution of