汽车油箱缝焊机说明书.doc

汽车油箱缝焊机液压及PLC系统设计
摘要
本文的第一部分是设计汽车油箱缝焊机的液压系统，采用液压传动主要是因为其具有工作比较平稳，体积小，反应快，输出功率大，易于实现自动化和过载保护等优点。在整个液压传动机构中，泵源选用了双联叶片泵供油，低压泵（大流量）用于快速进给和快速退回，高压泵（小流量）用于工作进给，优点是流量均匀，旋转平稳，噪音小，控制简便。由于本液压系统属于小功率调速系统，所以调速方式采用了调速阀式进口节流调速回路，其速度换接方式为电磁阀的快慢速换接回路。定位夹紧系统采用了二位四通电磁阀的夹紧方式，可以保证系统工作的可靠性。
本文的第二部分是液压系统的电气控制部分，是应用PLC实现的。设计中选用西门子S7-200可编程控制器，根据系统15个输入和8个输出点数，确定CPU226，满足系统I/O输入点数要求。设计PLC系统的顺序功能图，并转化成梯形图，满足系统夹紧缸夹紧－点焊进给缸快进－慢进－点焊-退回－缝焊进给缸快进－慢进－缝焊-退回－夹紧缸松开－原位卸荷动作循环要求。
关键词　液压系统; 组合机床;电磁阀;PLC控制器
Automobile fuel tankSeam welder Hydraulic and PLC system Design
Abstract
The first part of this article is about designing Automobile fuel tankSeam welder Hydraulic system. We adopt hydraulic because it owns many merits such as steady working ,small physical volume, large output power, being easy to realize automation and over loading protection and so the whole liquid press system double leaf pump provides oil ,of which the low pressure pump(large flux) is used for quickly going ahead and quickly returning ,the high pressure one (small flux) for working going ahead. Because this system is a small power speed-changing system, we adopt the speed-changing method of speed-changing valve entrance flux-limiting speed changing, its speed changing and connecting is the electric magnetic valve high/slow speed changing and connecting loof. The orientation and holding tightly system uses the two-position-five-direction electric magnetic valve that can ensure working reliance of the system.
The second part of this dissertation is about electric control of the liquid press system that uses PLC. In this part I choose Siemens S7-200 Programmable to this system 15 input,8 output point , determine to use CPU226,satisfy I/O point. Design the system of PLC sequential function chart,and turn toT chart,satisfy the system: clamping cylinder clamp - fast-forward spot feed tank - slow progress - spot - back - seam welding to the cylinder into the fast-forward -