1、中文2300字，1450英文单词，7500英文字符本科生毕业设计（论文） 外文翻译 毕业设计（论文）题目： 汽车主减速器的对比分析与设计 外文题目： AUTOMOTIWE FINAL DRIVE 译文题目： 汽车主减速器 学 生 姓 名： 专 业：
2、;车辆工程 指导教师姓名： 金嘉琦 评 阅 日 期： &nbs
3、p; AUTOMOTIWE FINAL DRIVE FINAL DRIVE A final drive is that part of a power transmission system between the drive shaft and the differential. Its function is to change the direction of the power transmitted &nbs
4、p;by the drive shaft through 90 degrees to the driving axles. At the same time. it provides a fixed reduction between the speed of the drive shaft and the axle driving the wheels. The reductio
5、n or gear ratio of the final drive is determined by dividing the number of teeth on the ring gear by the number of teeth on the pinion gear. In passenger vehicles, this speed
6、 reduction varies from about 3:1 to 5:1. In trucks it varies from about 5:1 to 11:1. To calculate rear axle ratio, count the number of teeth on each gear. Then divide the number of pinion teeth into the number of ring gear teeth. For example, if the pinion gear has 10 teeth and the
7、 ring gear has 30 (30 divided by 10), the rear axle ratio would be 3:1. Manufacturers install a rear axle ratio that provides a compromise between performance and economy. The average passenger car ratio is 3.50:1. T
8、he higher axle ratio, 4.11:1 for instance, would increase acceleration and pulling power but would decrease fuel economy. The engine would have to run at a higher rpm to maintain an equal cruising speed. The
9、lower axle ratio. 3:1, would reduce acceleration and pulling power but would increase fuel mileage. The engine would run at a lower rpm while maintaining the same speed. The major components of the
10、final drive include the pinion gear, connected to the drive shaft, and a bevel gear or ring gear that is bolted or riveted to the differential carrier. To maintain accurate and proper alignment &nbs
11、p;and tooth contact, the ring gear and differential assembly are mounted in bearings. The bevel drive pinion is supported by two tapered roller bearings, mounted in the differential carrier. &n
12、bsp; This pinion shaft is straddle mounted. meaning that a bearing is located on each side of the pinion shaft teeth. Oil seals prevent the loss of lubricant from the housing where the pinion shaft and ax
13、le shafts protrude. As a mechanic, you will encounter the final drive gears in the spiral bevel and hypoid design. Spiral Bevel Gear Spiral bevel gears have curved gear teeth with the pinion and ring gear on the same center line. This type of final drive is used e
14、xtensively in truck and occasionally in older automobiles. This design allows for constant contact between the ring gear and pinion. It also necessitates the use of heavy grade lubricants. Hypoid Gear The hypoid gear final drive is an improvement or variation of the spi
15、ral bevel design and is commonly used in light and medium trucks and all domestic rear- wheel drive automobiles. Hypoid gears have replaced spiral bevel gears because they lower the hump in the floor of the vehicle and improve gear-meshing action. As you can see in figure 5-13, the pinion meshes with the ring gear below the center line and is at a slight angle (less than 90 degrees).
