车辆工程机动车离合器的外文文献翻译

湖北文理学院

毕业设计(论文)英文翻译

题目有限元热分析的陶瓷离合器

专业车辆工程

班级Xxx

姓名Xxxx

学号*******xx

指导教师

职称Xxx 副教授

2014年2月25日

Fethermal analysis of a ceramic clutch

1. Introduction

Abrasive dry running vehicle clutches are force closure couplings. Torque and speed transmission are ensured by the frictional force generated between two pressed surfaces. Reasons for the application of ceramic as a friction medium include good heat and wear resistance properties, which provide the opportunity to drive higher pressures, and a low density. Thus, an increasing power density is enabled with a parallel minimization of construction space.

Measurements with a first prototype of a clutch disk using ceramic facings were performed at Karlsruhe University in a laboratory specialized in passenger car drive system testing. In the course of analysis the finite element (FE) model was to be constructed with the knowledge of measurement data and measurement conditions. Calculations were intended to determine the temperature distribution of the clutch disk and its environment at each moment in time corresponding to measurements. It is essential to be familiar with the temperature range in order to examine the wear characteristics of the system. Thus, important information is derived from measurement data. In critical load cases, the highest expected temperatures must be forecast in space and time in order to protect measuring instruments close to the location of heat generation.

The goal of this study is to analyze and modify the clutch system to

provide better operating conditions by improving the heat conduction and convection of the system or to increase the amount of the energy converted into frictional heat. Furthermore, it is desired to find better design solutions for more efficient clutch systems.

Calculations were performed by the Cosmos Design Star software. During model development, great care had to be taken for proper simplification of geometry, the selection of element sizes, and the correct adjustment of time steps due to the substantial hardware requirements for transient calculations. Changes in thermal parameters such as the surface heat convection coefficient and thermal load had to be taken into consideration on an on-going basis in terms of time and location. The two sides of the analyzed test clutch system can only be managed by two independent models linked by heat partition, according to the hypothesis that the contact temperature must be identical on both sides while there is proper contact between them and its value must be adjusted by iteration. Calculations revealed that the heat partition changed by cycle and it differed along the inner and outer contact rings. As a result of the different cooling characteristics between the ceramic and steel side, a heat flow is launched from the ceramic side to the steel side. This heat flow was also determined by iteration, its value also changes by cycle and differs along the inner and outer contact rings.

2. First prototype of a clutch using engineering ceramics as