摘 要

     目前，自动变速器在汽车领域的应用越来越广泛。其中主要原因是自动变速器能够根据路面状况自动改变车速，这极大地方便了驾驶者。不仅能够缓解驾驶者驾驶疲劳减少路面交通事故，而且还能够提高汽车的燃油经济性。同时，还能提高汽车的动力性。行星齿轮变速箱主要结构为行星齿轮机构，行星齿轮机构主要由太阳轮、外齿圈、行星轮、行星架组成。由于行星齿轮机构具有两个自由度，因此行星齿轮机构没有固定的的传动比，不能直接应用于变速器。为了能够将行星齿轮变速器应用于自动变速器，必须将齿轮机构中的元件固定使其具有一个自由度。只有一个自由度的行星齿轮机构具有固定的传动比，因此可以应用于自动变速器中。我设计的为商务车行星齿轮变速箱，行星齿轮机构具有结构紧凑、刚度大、传动平稳等优点。行星齿轮变速箱动力改变由液力变矩器进行控制，其操纵机构为离合器和制动器，并通过液压油进行控制，从而实现自动换挡。但是，自动变速器结构比较复杂。通过这次毕业设计我对自动变速器原理做了大量的工作并参考商务车车型最终确定了其传动方案，并对各档传动比做了详细的说明。

关键词：自动变速器，行星齿轮变速箱，液力变矩器，离合器

PLANETARY GEARBOX DESIGN OF COMMERCIAL VEHICLE

Abstract 

At present, more and more widely applied in the field of automatic transmission in car.The main reason is that automatic transmission can change the speed automatically according to the road conditions, it has made great drivers.Not only can alleviate drivers driving fatigue reduce road traffic accidents, but also can improve the fuel economy of the car.At the same time, it can improve power performance of car.Planetary gear transmission main structure for a planet gear mechanism, the planetary gear mechanism is mainly composed of the sun wheel, outer ring gear, planetary wheel, planet carrier.Because the planet gear mechanism has two degrees of freedom, so the planet gear mechanism has no fixed transmission ratio, cannot be directly applied to the transmission.In order to be able to will be applied in the automatic transmission planetary gear transmission, the gear mechanism of components must be fixed exhibit a degree of freedom.There is only one degree of freedom of planet gear mechanism has a fixed ratio, thus can be used in the automatic transmission.I design for commercial vehicles planetary gear transmission, the planet gear mechanism has the advantages of compact structure, large rigidity, smooth transmission.Planetary gear transmission power changes controlled by hydraulic torque converter, its operating mechanism for the clutch and brake, and the control with the hydraulic oil, so as to realize automatic shift.However, the automatic transmission structure is more complex.Through this graduation design I made a lot of work on automatic transmission principle and refer to commercial vehicles models ultimately determine the transmission scheme, and has made the detailed instructions for each transmission ratio. 

Key Words: automatic transmisson,lanetary gearbox, torque converter, clutch

目 录

第1章 行星齿轮的结构和工作原理

第2章 自动变速器的基本组成 3

第3章 液力变矩器的工作原理 6

第4章 自动变速器传动方案及传动原理

§4.1 自动变速器的传动方案

§4.2 自动变速器的传动原理

§4.2.1 空挡或驻车挡的传动原理

§4.2.2 D位D1挡汽车加速与滑行时传动原理

§4.2.3 汽车在L位一挡时前后行星排的传动原理

§4.2.4 D位D2挡传动原理图

§4.2.5 二挡时自动变速器的传动原理图

§4.2.6 D位D3挡时，自动变速器的传动原理

§4.2.7  超速挡传动原理

§4.2.8 自动变速器的倒档传动原理

第5章 行星齿轮机构设计计算

§5.1 变速器齿轮传动的设计计算

§5.1.1 各挡位传动比

§5.1.2 齿轮参数设计计算

§5.1.3实际传动比 28

§5.1.4  齿轮强度校核 29

§5.2  换挡执行机构

§5.2.1  多片离合器

§5.2.2  制动器

§5.2.3  单向超越离合器

结 论

致 谢

参考文献

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