真空助力器壳体成形与设计

分类号

密级

毕业设计(论文)

真空助力器壳体成形与设计

所在学院机械与电气工程学院

专业机械设计制造及其自动化班级11机自x班

姓名

学号

指导老师

2015年 3 月31 日

摘要

踏动踏板时，踏板力经杠杆放大（踏板比），作用于真空助力器的阀杆上，并压缩阀杆回动簧，推动空气阀座向前移动，经过反馈盘和主缸推杆传递，使制动主缸的第一活塞移动，产生液压，制动轮缸产生张开力，推动制动蹄片产生制动力。

与此同时，橡胶阀部件在阀杆簧的作用下，随同空气阀座一起移动，关闭真空阀口，使前后气室隔开，即后气室与真空源断开。（这是一瞬间过程）

随着阀杆的继续移动，空气阀座与橡胶阀部件离，空气阀口打开，外界空气经泡沫滤芯、橡胶阀部件的内孔和大气阀口进入后气室，这样前后两气室产生气压差，这个气压差在助力器的膜片、助力盘、阀体上产生作用力，除一小部分用来平衡弹簧抗力和系统阻力外，大部分经阀体作用在反馈盘上，并传递到制动主缸。在这个过程中，真空阀口始终处于关闭状态。

在踏动踏板的过程中，阀杆向前移动，空气经打开的空气阀口，不断地进入后气室，阀体不断地向前移动。当踏板停留在某一位置时，阀体则移动到空气阀口关闭的位置，此时空气阀口和真空阀口均处于关闭状态，助力器处于一平衡状态，即阀杆的输入力、前后气室产生的伺服力和主缸液压产生的作用力（助力器的输出力的反作用力）三者之间保持平衡。当前后气室的气压差达到最大，即后气室的气压完全为大气气压时，则真空助力器达到最大助力点，此后，输入力的变化与输出力的变化相等，即没有伺服力的增加。 3 释放制动踏板，阀杆回动簧立即将阀杆和空气阀座推回，使空气阀口关闭，真空阀品开启，阀体在回位簧的作用下，回到初始位置，助力器回到非工作状态。 4 制动主缸实现力与液压的转换助力器的输出力直接作用在与之相连的制动主缸的第一活塞上，从而把力转换为液压，输出到车轮的制动分泵，再由制动分泵转换成力，实现汽车的制动。

关键词：真空助力器；真空助力器；改进设计

Abstract

The development direction of harvester will be to high-tech direction, making out the applicability of harvester is the development of the market, is very promising for different regions developed different harvester. Thus, the corresponding manufacturing combine high performance is the development of foreign harvester. The rice combine harvester can complete harvesting, threshing, separation and bagging operations at one time. The machine has the advantages of small volume, light weight, flexible operation, through and good adaptability, can better solve the problem of big, medium-sized harvester to harvest in the hilly, mountainous and paddy field. Thus, the corresponding manufacturing combine high performance is the development of foreign harvester. The rice combine harvester can complete harvesting, threshing, separation and bagging operations at one time. The machine has the advantages of small volume, light weight, flexible operation, through and good adaptability, can better solve the problem of big, medium-sized harvester to harvest in the hilly, mountainous and paddy field.Thus, the corresponding manufacturing combine high performance is the development of foreign harvester. The rice combine harvester can complete harvesting, threshing, separation and bagging operations at one time. The machine has the advantages of small volume, light weight, flexible operation, through and good adaptability, can better solve the problem of big, medium-sized harvester to harvest in the hilly, mountainous and paddy field.Thus, the corresponding manufacturing combine high performance is the development of foreign harvester. The rice combine harvester can complete harvesting, threshing, separation and bagging operations at one time. The machine has the advantages of small volume, light weight, flexible operation, through and good adaptability, can better solve the problem of big, medium-sized harvester to harvest in the hilly, mountainous and paddy field.Thus, the corresponding manufacturing combine high performance is the development of foreign harvester. The rice combine harvester can complete harvesting, threshing, separation and bagging operations at one time. The machine has the advantages of small volume, light weight, flexible operation, through and good adaptability, can better solve the problem of big, medium-sized harvester to harvest in the hilly, mountainous and paddy field.Thus, the corresponding manufacturing combine high performance is the development of foreign harvester. The rice combine harvester can complete harvesting, threshing, separation and bagging operations at one time. The machine has the advantages of small volume, light weight, flexible operation, through and good

宁波大红鹰学院毕业设计（论文）

adaptability, can better solve the problem of big, medium-sized harvester to harvest in the hilly, mountainous and paddy field.

Key Words: rice thresher threshing; improved design;

目录

摘要 ....................................................................................................................................... II Abstract..................................................................................................................................... III 目录 ....................................................................................................................................... V 第1章绪论 (1)

第2章总体方案确定 (3)

2.1 真空助力器工作原理 (3)

2.2真空助力器总体设计 (4)

2.2.1真空助力器的组成部分 (4)

2.2.2 真空助力器的整机结构及选择 (7)

2.2.3 真空助力器的工作流程 (7)

第3章真空助力器结构设计 (8)

3.1 外壳设计 (8)

3.2 内部零部件选择 (9)

第4章模具成型设计 (13)

4.1 上盖模具设计 (13)

4.1.1 冲头的设计 (13)

4.1.2 底模的设计 .................................................................... 错误！未定义书签。

4.2 下盖模具设计 (14)

4.2.1 冲头的设计 (9)

4.2.2 底模的设计 (11)

第5章销轴的设计与计算 (17)

5.1 轴的材料选择 (17)

第6章材料成型特性 (19)

6.1材料成型简介 ............................................................................. 错误！未定义书签。

6.2 上盖成型工艺设计 .................................................................. 错误！未定义书签。

6.3 下盖成型工艺设计 .................................................................. 错误！未定义书签。