Planetary pin roller lead screw

Abstract

The invention relates to a planetary pin roller lead screw, and belongs to the field of pin roller lead screw design. The planetary pin roller lead screw comprises a lead screw body, two inner gear rings, a nut, two bearing retainers, two steel wire locking rings, N pin rollers and a positioning pin. The N pin rollers are evenly distributed circumferentially on the outer wall of the lead screw body; the outer wall of the lead screw body is sleeved with the two bearing retainers; the two bearing retainers are located at the two axial ends of the pin rollers respectively; the two axial ends of the pin rollers extend into the two bearing retainers respectively; the two inner gear rings sleeve the outer walls of the two axial ends of the N pin rollers respectively; the nut sleeves the outer walls of the N pin rollers; the nut is fixedly connected with the inner gear rings through the positioning pin; and the two steel wire locking rings are arranged at the axial outer ends of the contact positions of the corresponding bearing retainers and the nut. Axial limiting is realized. The lead screw integrates characteristics of planetary gear transmission and threaded transmission, and converts the rotary motion into the linear motion.

Description

technical field [0001] The invention belongs to the field of roller screw design and relates to a planetary roller screw. Background technique [0002] Compared with ball screws, differential planetary roller screws have stronger bearing capacity, higher rigidity, simpler structure, and higher reliability, and are widely used in heavy-duty fields such as braking mechanisms and electromechanical servos. However, the differential planetary roller screw has the problem of unstable transmission ratio. The reason is that the movement and load are transmitted between the roller and the nut only by friction, without any rolling limiting mechanism, and are subject to manufacturing and assembly under load. Influenced by precision, etc., there will be a relative slip between the nut and the roller, resulting in a change in the transmission ratio of the planetary roller screw, making it impossible to achieve a fixed transmission ratio transmission. In the past, the effect of slip was ...

AI Technical Summary

Problems solved by technology

However, the differential planetary roller screw has the problem of unstable transmission ratio. The reason is that the movement and load are transmitted between the roller and the nut only by friction, without any rolling limiting mechanism, and are subject to manufacturing and assembly under load. Influenced by precision, etc., there will be a relative slip between the nut and the roller, resulting in a change in the transmission ratio of the planetary roller screw, and it is impossible to achieve a fixed transmission ratio transmission.

In the past, the influence of slip was eliminated by increasing the pre-tightening force. For example, a planetary roller screw transmission mechanism was proposed in the CN103133619A patent. This method can meet the effect of eliminating slip for small load conditions, but when the load exceeds the preload, it will still cause slip and cannot achieve constant transmission ratio transmission

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