液压与气压传动(第2版) 姚林晓 著 专业科技 文轩网

目 录 章 绪论 ·················································································································.1 1.1 液压与气压传动基本原理、组成和图形符号 ·······························································.2 1.1.1 液压与气压传动基本原理 ·············································································.2 1.1.2 液压与气压传动系统的组成 ··········································································.4 1.1.3 液压传动图形符号 ······················································································.5 1.2 液压与气压传动的优缺点 ·······················································································.6 1.2.1 液压与气压传动的优点 ················································································.6 1.2.2 液压与气压传动的缺点 ················································································.6 1.3 液压与气压传动的应用与发展 ·················································································.7 1.3.1 液压与气压传动的应用 ················································································.7 1.3.2 液压与气压传动技术的发展 ··········································································.8 1.4 本书内容安排 ······································································································.8 本章小结 ···················································································································.9 思考与练习 ················································································································.9 第2 章 液压流体力学 ·································································································.10 2.1 液体的主要物理性质 ···························································································.10 2.1.1 密度 ······································································································.10 2.1.2 压缩性和膨胀性 ·······················································································.11 2.1.3 黏性 ······································································································.11 2.2 液体静力学 ·······································································································.13 2.2.1 液体所受的作用力 ····················································································.13 2.2.2 静止液体微分方程的推导 ···········································································.14 2.2.3 静止液体微分方程的应用 ···········································································.15 2.2.4 压力的表示方法及单位 ··············································································.17 2.3 流动液体的力学基本规律 ·····················································································.18 2.3.1 经典流体力学研究方法介绍 ········································································.18 2.3.2 流动液体力学的基本概念 ···········································································.19 2.3.3 流动液体的连续性方程 ··············································································.20 2.3.4 理想液体流动的微分方程 ···········································································.20 2.3.5 伯努利方程 ·····························································································.21 2.3.6 动量方程 ································································································.22 2.4 液体在流动中的能量损失 ·····················································································.24 2.4.1 流态实验和雷诺数 ····················································································.24 2.4.2 液体圆管流动中的沿程压力损失 ··································································.26 2.4.3 液体流动中的局部压力损失 ········································································.29 2.4.4 管道系统中的总压力损失和压力效率 ····························································.30 2.5 液体在小孔和缝隙中的流动 ··················································································.32 2.5.1 液体在小孔中的流动 ·················································································.32 2.5.2 液体在缝隙中的流动 ·················································································.34 2.6 液压卡紧问题 ····································································································.40 2.6.1 液压卡紧的概念 ·······················································································.40 2.6.2 液压卡紧现象的原因分析 ···········································································.40 2.6.3 解决液压卡紧现象的措施 ···········································································.41 2.7 液压冲击 ··········································································································.41 2.7.1 阀门突然关闭引起液压冲击的物理过程 ·························································.42 2.7.2 液压冲击力的计算 ····················································································.42 2.7.3 减轻液压冲击的措施 ·················································································.43 2.8 空穴现象与气蚀现象 ···························································································.43 2.8.1 空气分离压与饱和蒸汽压 ···········································································.43 2.8.2 空穴现象 ································································································.44 2.8.3 气蚀现象 ································································································.45 本章小结 ·················································································································.45 思考与练习 ··············································································································.45 第3 章 液压泵和液压马达 ··························································································.48 3.1 概述 ················································································································.49 3.1.1 工作原理 ································································································.49 3.1.2 液压泵与液压马达的分类 ···········································································.50 3.1.3 液压泵和液压马达的基本参数 ·····································································.51 3.2 齿轮泵 ·············································································································.54 3.2.1 工作原理 ································································································.54 3.2.2 流量计算和流量脉动 ·················································································.55 3.2.3 外啮合齿轮泵的结构特点和优缺点及提高齿轮泵压力的措施 ······························.56 3.2.4 齿轮液压马达 ··························································································.59 3.3 叶片泵 ·············································································································.61 3.3.1 单作用叶片泵 ··························································································.61 3.3.2 双作用叶片泵 ··························································································.63 3.3.3 叶片液压马达 ··························································································.65 3.4 轴向柱塞泵 ·······································································································.65 3.4.1 斜盘式轴向柱塞泵的工作原理 ·····································································.66 3.4.2 斜盘式轴向柱塞泵典型结构 ········································································.67 3.4.3 总功率变量泵 ··························································································.73 3.5 负载敏感泵 ·······································································································.74 3.5.1 负载敏感泵的节能工作原理 ········································································.75 3.5.2 负载敏感泵的应用 ····················································································.76 3.6 多作用内曲线低速大转矩液压马达 ·········································································.78 3.6.1 结构组成 ································································································.79 3.6.2 工作原理 ································································································.80 本章小结 ·················································································································.80 思考与练习 ··············································································································.81 第4 章 液压缸 ···········································································································.82 4.1 液压缸的分类和工作原理 ·····················································································.83 4.1.1 液压缸的分类 ··························································································.83 4.1.2 液压缸的工作原理 ····················································································.84 4.2 液压缸的典型结构 ······························································································.90 4.2.1 液压缸的结构组成 ····················································································.90 4.2.2 液压缸的主要零件及装置 ···········································································.91 4.3 液压缸的设计和计算 ···························································································.95 4.3.1 液压缸设计过程中应注意的问题 ··································································.95 4.3.2 液压缸的主要尺寸确定 ··············································································.96 4.3.3 液压缸的强度校核 ····················································································.97 4.3.4 液压缸的稳定性校核 ·················································································.98 4.3.5 缓冲计算 ································································································.99 4.3.6 拉杆计算 ································································································.99 本章小结 ················································································································.101 思考与练习 ·············································································································.101 第5 章 液压控制阀 ···································································································.103 5.1 概述 ···············································································································.104 5.1.1 按功用分类 ····························································································.104 5.1.2 按控制方式分类 ······················································································.104 5.1.3 按结构形式分类 ······················································································.105 5.1.4 按连接方式分类 ······················································································.105 5.2 压力控制阀 ······································································································.106 5.2.1 溢流阀 ··································································································.106 5.2.2 减压阀 ··································································································.114 5.2.3 顺序阀 ··································································································.116 5.2.4 平衡阀 ··································································································.117 5.2.5 专用平衡阀 ····························································································.118 5.2.6 压力继电器 ····························································································.119 5.3 流量控制阀 ······································································································.121 5.3.1 节流阀和单向节流阀 ················································································.122 5.3.2 调速阀 ··································································································.124 5.3.3 分流集流阀 ····························································································.126 5.3.4 单路稳流阀 ····························································································.128 5.4 方向控制阀 ······································································································.131 5.4.1 单向阀 ··································································································.131 5.4.2 换向阀 ··································································································.135 5.5 工程机械常用液压阀 ··························································································.142 5.5.1 多路换向阀 ····························································································.142 5.5.2 减压阀式先导控制阀 ················································································.145 5.6 新型液压阀 ······································································································.147 5.6.1 电液比例阀 ····························································································.147 5.6.2 数字阀 ··································································································.149 本章小结 ················································································································.152 思考与练习 ·············································································································.154 第6 章 液压油和液压系统辅助元件 ···········································································.156 6.1 液压油 ············································································································.157 6.1.1 液压系统对液压油的基本要求 ····································································.157 6.1.2 液压油的特性 ·························································································.157 6.1.3 液压油的选择和使用 ················································································.159 6.1.4 液压油的污染及其控制 ·············································································.160 6.2 蓄能器 ············································································································.162 6.2.1 蓄能器的作用和分类 ················································································.162 6.2.2 蓄能器容积计算 ······················································································.164 6.2.3 蓄能器的使用和安装 ················································································.166 6.3 滤油器 ············································································································.166 6.3.1 滤油器的分类 ·························································································.167 6.3.2 滤油器的选用和安装 ················································································.169 6.4 油箱和热交换器 ································································································.170 6.4.1 油箱 ·····································································································.170 6.4.2 热交换器 ·······························································································.172 6.5 其他辅助元件 ···································································································.175 6.5.1 密封件 ··································································································.175 6.5.2 管件 ·····································································································.178 6.5.3 压力表 ··································································································.181 本章小结 ················································································································.181 思考与练习 ·············································································································.181 第7 章 液压基本回路 ································································································.183 7.1 压力控制回路 ···································································································.184 7.1.1 调压回路 ·······························································································.184 7.1.2 减压回路 ·······························································································.186 7.1.3 增压回路 ·······························································································.187 7.1.4 卸荷回路 ·······························································································.188 7.1.5 保压回路 ·······························································································.190 7.1.6 缓冲补油回路 ·························································································.191 7.2 速度控制回路 ···································································································.194 7.2.1 调速回路 ·······························································································.194 7.2.2 平衡回路 ·······························································································.202 7.2.3 增速回路 ·······························································································.203 7.2.4 快慢速换接回路 ······················································································.204 7.3 方向控制回路 ···································································································.206 7.3.1 换向回路 ·······························································································.206 7.3.2 浮动回路 ·······························································································.207 7.3.3 锁紧回路 ·······························································································.209 7.4 多执行元件控制回路 ··························································································.211 7.4.1 顺序动作回路 ·························································································.212 7.4.2 同步回路 ·······························································································.215 7.4.3 多缸快慢速互不干扰回路 ··········································································.216 本章小结 ················································································································.218 思考与练习 ·············································································································.218 第8 章 典型液压系统 ································································································.222 8.1 组合机床动力滑台液压系统 ·················································································.223 8.1.1 YT 4543 型动力滑台液压系统的性能要求 ······················································.223 8.1.2 YT 4543 型动力滑台液压系统的工作原理 ······················································.224 8.1.3 YT 4543 型动力滑台液压系统的特点 ····························································.226 8.2 液压机液压系统 ································································································.226 8.2.1 YB 32-200 型液压机液压系统的性能要求 ······················································.226 8.2.2 YB 32-200 型液压机液压系统的工作原理 ······················································.227 8.2.3 YB 32-200 型液压机液压系统的特点 ····························································.230 8.3 汽车起重机液压系统 ··························································································.231 8.3.1 Q 2-8 型汽车起重机的液压系统性能要求 ······················································.231 8.3.2 Q 2-8 型汽车起重机液压系统的工作原理 ······················································.231 8.3.3 Q 2-8 型汽车起重机液压系统的特点 ····························································.234 8.4 塑料注射成形机液压系统 ····················································································.234 8.4.1 塑料注射成形机液压系统的性能要求 ···························································.236 8.4.2 塑料注射成形机液压系统的工作原理 ···························································.236 8.4.3 塑料注射成形机液压系统的特点 ·································································.238 8.5 挖掘机液压系统 ································································································.239 8.5.1 挖掘机液压系统的性能要求 ·······································································.239 8.5.2 挖掘机液压系统的工作原理 ·······································································.239 8.5.3 YW-60 型挖掘机液压系统的特点 ·································································.243 8.6 带钢张力电液伺服液压系统 ·················································································.244 8.6.1 带钢张力电液伺服液压系统的性能要求 ························································.244 8.6.2 带钢张力电液伺服液压系统的工作原理 ························································.244 8.6.3 带钢张力电液伺服液压系统的特点 ······························································.245 本章小结 ················································································································.245 思考与练习 ·············································································································.245 第9 章 液压系统设计与计算 ·····················································································.247 9.1 液压系统的一般设计流程 ····················································································.248 9.2 系统工况分析与负载匹配 ····················································································.248 9.2.1 负载分析与负载循环图 ·············································································.249 9.2.2 运动分析及运动循环图 ·············································································.252 9.2.3 负载匹配 ·······························································································.253 9.3 液压系统设计 ···································································································.254 9.3.1 确定系统主要参数 ···················································································.254 9.3.2 拟定液压系统工作原理图 ··········································································.258 9.3.3 液压元件的选型 ······················································································.260 9.3.4 液压系统性能验算 ···················································································.266 9.3.5 结构设计及技术文件编制 ··········································································.268 9.4 液压系统设计实例 ·····························································································.271 9.4.1 系统工况分析 ·························································································.271 9.4.2 主要参数的确定 ······················································································.272 9.4.3 拟定液压系统工作原理图 ··········································································.274 9.4.4 液压元件的选择 ······················································································.277 9.4.5 液压系统的性能验算 ················································································.279 9.5 液压系统动态特性分析 ·······················································································.279 9.5.1 液压系统动态特性分析的作用 ····································································.279 9.5.2 液压系统动态特性分析的内容和方法 ···························································.281 9.5.3 系统数学模型 ·························································································.285 9.5.4 动态特性分析实例 ···················································································.285 本章小结 ················································································································.293 思考与练习 ·············································································································.293 0 章 气压传动 ·····································································································.294 10.1 气压传动概述 ·································································································.295 10.1.1 气压传动的特点 ·····················································································.295 10.1.2 气压传动系统的组成 ···············································································.295 10.2 气动元件 ·······································································································.296 10.2.1 气源装置 ······························································································.297 10.2.2 辅助元件 ······························································································.300 10.2.3 气动执行元件 ························································································.301 10.2.4 气动控制元件 ························································································.303 10.2.5 气动逻辑元件 ························································································.309 10.3 气动基本回路 ·································································································.313 10.3.1 方向控制回路 ························································································.313 10.3.2 压力控制回路 ························································································.313 10.3.3 速度控制回路 ························································································.314 10.3.4 其他回路 ······························································································.317 10.4 气动系统应用实例 ···························································································.319 10.4.1 气液动力滑台的气动系统 ·········································································.320 10.4.2 射芯机气动系统 ·····················································································.321 本章小结 ················································································································.323 思考与练习 ·············································································································.323 参考文献 ·····················································································································.324 附录 GBT 786.1―2009《流体传动系统及元件图形符号和回路图》（节选） ···············.326