Mechanical friction type stepless speed change device

Abstract

A mechanical friction type stepless speed variator is composed of mechanical pressing and speed-regulating mechanism, pressing disk, pressing spring and the friction set with complex generating line.Said friction set consists of static conic disk and moving conic disk, which are coaxial and have opposite conic surfaces, which are in contact by flexible closed-loop friction formed by frictino disks or pins. Said conic surface comprises a straight-line segment and a curve segment. Said mechanical pressing and speed-regulating mechanism is composed of bidirectional three-position clutch, symmetric planetary gear train, gear nut and external gear.

Description

technical field [0001] The invention relates to continuously variable transmission technology, in particular to a mechanical friction continuously variable transmission device with intermediate flexible elements such as belts and chains. Background technique [0002] Continuously variable transmission is a mechanical transmission device with continuously adjustable transmission ratio. Because it can adapt to the requirements of changing working conditions or continuously changing speed during machine operation, it is not only widely used in light industrial sectors such as textiles, food, paper, rubber, etc., but also It is also used in various mechanical equipment such as working machine (machine tool), overweight transportation, petrochemical industry, etc., especially its successful application in automobile transmission in recent years. [0003] The basic composition of mechanical friction continuously variable transmission for automobiles includes oil pump, forward and ...

AI Technical Summary

Problems solved by technology

One of the cone-disk busbars is a straight busbar, which has the advantages of large contact area, low contact stress, and high service life of the friction pair surface. The disadvantage is that the deflection between the belt (chain) symmetry axis and the cone-disk rotation axis will inevitably occur during the speed change process, which will affect the transmission. In order to reduce the deviation, the gear ratio should not be large, and generally only achieve R=5~6; the other is a curved generatrix, and the side where the friction plate (or pin end) contacts the cone is the friction working surface, and the working surface The busbar is a curve (Chinese patent, patent No. 00212516.1), and its conical-disc-curved busbar and the side shape of the belt (chain) form a pair of conjugate curves. Vertical, stable transmission, the disadvantage is that the contact stress is slightly larger, thus affecting the life

In addition, in addition to belts and toothed chains in the pressurization and speed regulation system, metal belt and pendulum chain continuously variable transmissions mostly use hydraulic pressurized speed regulation systems. At present, almost all CVTs for automobiles use hydraulic pressure Pressurization and speed regulation systems, such as figure 1 The machine-hydraulic control system shown includes driving wheel oil cylinder 31, pulley position sensor 32, pitot tube 33, speed ratio control valve 34, throttle control cam 35, flexible steel wire 36, throttle valve 37, accelerator pedal 38, main pressure Control valve 39, oil pump 40, thrust metal belt 41, driven wheel oil cylinder 42 and pulley, etc., such as figure 2 The electro-hydraulic control system shown includes a driving cone wheel 51, a safety valve 52, a speed ratio valve 53, a clamping force control valve 54, a brake pedal 55, a throttle valve 56, a driven cone wheel 57 and an electric control device, etc. Its technology is very mature, but its shortcomings are obvious, that is, an oil pump is needed to support the hydraulic system, and power loss is inevitable. The pumps, valves, cylinder pistons, and seals (especially high-speed rotary seals) used in the system make the system complex. Not only the parts Many, require precision machining, and have high requirements for oil cleanliness, which are much higher than ordinary lubricating oils, so the reliability is reduced

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