液压气动控制技术课程设计
液压传动国民济领域中应十分广泛专业液压机械工作求工况特点动作循环作液压机械部分液压系统满足液压机械项技术求系统构成工作原理采液压元件作特点等相教材中介绍YT4543型动力滑台注塑机船舶起货机等三种机械设备液压系统分析工作原理性特点试图通实例学者掌握分析液压系统般步骤方法实际液压系统较复杂读懂液压系统图非易事初学者说需通量读图分析循序渐进积累验逐步掌握分析液压系统般步骤方法面出例供学者参考：
例1．图示液压机械动作循环快进工进二工进快退停止读懂液压系统原理图分析系统中油液流动情况填写电磁铁动作序表说明系统特点
a1
a2
a1＞a2
注：图中a1 a2分阀7阀9节流口通流面积
（1）系统油液流动情况
快进
进油路 液压泵2――三位四通换阀4（左位）――液压缸杆腔
回油路 液压缸杆腔――二位二通阀10（左位）――三位四通换阀4（左位）――油箱
工进
进油路 液压泵2――三位四通换阀4（左位）――液压缸杆腔
回油路 液压缸杆腔――二位二通阀6（左位）――调速阀7――三位四通换阀4（左位）――油箱
二工进
进油路 液压泵2――三位四通换阀4（左位）――液压缸杆腔
回油路 液压缸杆腔――二位二通阀8（左位）――调速阀9――三位四通换阀4（左位）――油箱
快退
进油路 液压泵2――三位四通换阀4（右位）――液压缸杆腔
回油路 液压缸杆腔――三位四通换阀4（右位）――油箱
（2）电磁铁动作序表
电磁铁
动作
1DT
2DT
3DT
4DT
5DT
快进
－
＋
－
－
－
工进
－
＋
＋
－
＋
二工进
－
＋
－
＋
＋
快退
＋
－
－
－
－
停止
－
－
－
－
－
注：电磁铁吸合标＋电磁铁断开标－
（3）液压系统特点
液压系统调速回路属回油路节流调速回路液压系统速度换接回路采联调速阀二次进回路二位二通阀68互相切换时回油分通两通油截面调速阀返回油箱实现两种进速度
三位四通换阀中位机H型实现系统卸荷
例2．图示液压系统动作循环夹紧快进工进快退放松试读懂液压系统图说明油液流动情况完成液压系统动作循环表
夹紧 放松
（1）油液流动情况
夹紧
进油路 液压泵2――减压阀4――单阀5――二位四通阀6（左位）――液压缸9杆腔
回油路 液压缸9杆腔――二位四通阀6（左位）――油箱
快进
进油路 液压泵2 ――三位四通阀11（左位）――液压缸10杆腔
回油路 液压缸10杆腔――三位四通阀11（左位）――二位二通阀13（左位）――油箱
工进
进油路 液压泵2 ――三位四通阀11（左位）――液压缸10杆腔
回油路 液压缸10杆腔――三位四通阀11（左位）――调速阀12――油箱
快退
进油路 液压泵2――三位四通阀11（右位）――液压缸10杆腔
回油路 液压缸10杆腔――三位四通阀11（右位）――二位二通阀13（左位）――油箱
放松
进油路 液压泵2――减压阀4――单阀5――二位四通阀6（右位）――液压缸9杆腔
回油路 液压缸9杆腔――二位四通阀6（右位）――油箱
（2）系统动作循环表
电磁铁
动作
1DT
2DT
3DT
4DT
缸9夹紧
－
－
－
＋
缸10快进
＋
－
－
＋
缸10工进
＋
－
＋
＋
缸10快退
－
＋
－
－
缸9松开
＋
－
＋
－
停止
－
－
－
－
注：电磁铁吸合标＋电磁铁断开标－
面题请学行完成
题 图示液压系统动作循环快进工进二工进快退试读懂液压系统图说明油液流动情况完成液压系统动作循环表
注：a1a2分调速阀78通油面积
液压系统应分析（2）
液压系统应分析（1）中讲实际液压系统较复杂读懂液压系统图非易事初学者说需通量读图分析循序渐进积累验逐步掌握分析液压系统般步骤方法面出例供学者参考：
例题 动作循环表说明阅读图示液压系统原理图说明系统动作油液流动状况完成电气元件动作循环表分析系统特点
动作名称
电气元件
1YA
2YA
11YA
12YA
21YA
22YA
YJ
定位夹紧
快进
工进卸荷
快退
松开拔销
原位卸荷
备注：（1）ⅠⅡ两回路进行独立循环动作互约束
（2）12YA22YA中通电时1YA便通电12YA22YA均断电时1YA断电
系统供油回路定位夹紧回路工作油路Ⅰ工作油路Ⅱ组成ⅠⅡ两回路进行独立循环动作互约束动作序表列
油路Ⅰ油液流动情况
1．定位夹紧
定位缸定位：
进油路线：高压流量泵→减压阀→单阀→2位4通换阀（左位）→定位缸
杆腔
回油路线：定位缸杆腔→2位4通换阀左位→节流阀→油箱
夹紧缸夹紧：
进油路线：高压流量泵→减压阀→2位4通换阀（左位）→序阀→夹紧缸杆腔
回油路线：夹紧缸杆腔→2位4通换阀（左位）→节流阀→油箱
夹紧工件进油路压力升高压力继电器（YJ）动作发信号1YA11YA12YA通电启动油路Ⅰ（1YA21YA22YA通电启动油路Ⅱ缸Ⅱ快进）
2．快进 1YA通电11YA12YA通电
进油路线：低压流量泵→2位5通换阀右位→缸Ⅰ杆腔
回油路线：缸Ⅰ杆腔→2位3通换阀左位→2位5通换阀右位→缸Ⅰ杆腔
泵输出油液缸Ⅰ两腔互通形成差动连接实现快速运动
3．工进卸荷（低） 1YA断电12YA断电11YA通电
进油路线：高压流量泵→2位5通换阀左位→2位3通换阀左→缸Ⅰ杆腔
回油路线：缸Ⅰ杆腔→调速阀→油箱
实现工进速度调速阀调节属回油路节流调速1YA断电先导式溢流阀
荷口通油箱低压流量泵溢流阀荷
4．快退 1YA通电12YA通电11YA断电
进油路线：低压流量泵→2位5通换阀右位→缸（Ⅰ）杆腔
回油路线：缸（Ⅰ）杆腔→2位3通换阀右位→油箱
实现快速退回
5松开拔销 2YA通电1YA断电
进油路线：高压流量泵→减压阀→单阀→2位4通换阀右位→时定位
夹紧缸杆腔相通
回油路线：夹紧缸杆腔→单序阀中单阀→
（合流）——
定位缸杆腔 ———————————→
→2位4通换阀右位→节流阀→油箱
6 原位卸荷（低） 电器元件均断电处图示状态
二 油路Ⅱ油液流动情况
定位夹紧油路Ⅰ完全相仅分析快进工进快退
1．定位夹紧 油路Ⅰ
2．快进： 1YA通电21YA通电22YA通电
进油路线：低压流量泵→2位5通换阀右位→2位3通换阀左位→缸Ⅱ杆腔
回油路线：缸Ⅱ杆腔→2位5通换阀右位→2位3通换阀左位→缸Ⅱ杆腔
泵输出油液缸Ⅱ两腔互通实现差动连接实现快速进运动
3．工进卸荷（低） 21YA通电22YA断电1YA断电
进油路线：高压流量泵→调速阀→2位3通换阀左位→缸Ⅱ杆腔
回油路线：缸Ⅱ杆腔→2位5通换阀左位→单阀→油箱
调速阀调节工进速度属进油路节流调速回路单阀回油路建立背压工进速度稳定低压流量泵卸荷油路Ⅰ
4快退 1YA通电22YA通电21YA断电
进油路线：低压流量泵→2位5通换阀右位→缸（Ⅱ）杆腔
回油路线：缸（Ⅱ）杆腔→2位3通换阀右位→油箱
电器元件动作表
动作名称
电器元件
1YA
2YA
11YA
12YA
21YA
22YA
YJ
定位夹紧
－
－
－
－
－
－
+
快进
+
－
+
+
+
+
（+）
工进卸荷（低）
－
－
+
－
+
－
（+）
快退
+
－
－
+
－
+
（+）
松开拔销
－
+
－
－
－
－
－
原位卸荷（低）
－
－
－
－
－
－
－
三 系统特点
1．分析知回路ⅠⅡ独立互干扰实现工件加工求扩加工范围
2．快进快退两回路均低压流量泵供油快进时均差动连接提高快进速度
3．工进时低压流量泵卸荷节省源减少油液发热
4．调速回路均节流调速回路Ⅰ回油节流调速回路Ⅱ进油节流调速回油路加背压保证工进速度稳定
5．快进快退时高压流量泵卸荷功率损失
液压系统中压力控制阀
液压系统中压力控制阀调定系统回路分支回路压力功分类常压力控制阀溢流阀减压阀序阀压力继电器等压力控制阀结构相似性差系统中作相搞清区联系学压力控制回路液压系统分析非常重
溢流阀
功 溢流阀功通阀口溢流控系统回路压力保持稳定实现稳压调压限压作
特点 结构溢流阀直动式先导式两种直动式溢流阀压力较高流量较时求调压弹簧刚度调节性较差滑阀泄漏高压控制难实现低压流量场合先导式溢流阀特点先导阀控制阀溢流阀阀溢流时溢流阀进口压力维持先导阀弹簧调定定值先导式溢流阀特点具远程控制口方便实现系统卸荷远程调压
溢流阀泄漏油流先导阀油液返回油箱时泄外泄两种方式泄时泄漏油流弹簧腔先导阀弹簧腔通阀体连接通道出油口相通外泄时泄漏油流先导阀油液直接单独引回油箱
应 溢流阀途：（1）定量泵出口联溢流阀调节泵出口压力（2）变量泵出口联溢流阀系统起载保护作（3）回油路接入直动式溢流阀执行元件运动稳（4）利先导式溢流阀远程控制口实现系统卸荷远程调压总系统中溢流阀作溢流阀安全阀背压阀调节系统压力系统卸荷
二减压阀
功 减压阀功流减压阀油液压力降低减压阀出口连接回路压力保持稳定减压阀出口压力维持恒定受进口压力通流量影响
特点 结构减压阀直动式先导式两种分场合
减压阀阀心处原始位置时阀口开阀进出口沟通阀心出口处压力控制出口压力未达调定压力时阀口全开阀心动出口压力达调定压力时阀心移阀口关调定压力达衡减压阀出口处输出油液时出口压力够基保持恒定时少量油液先导阀流回油箱
减压阀溢流阀区：（1）减压阀保持出口处压力基变溢流阀保持进口处压力基变（2）工作时减压阀进出油口互通溢流阀进出油口通（3）减压阀求外泄先导阀弹簧腔需通泄油口单独外接油箱溢流阀允许泄先导阀弹簧腔通阀体连接通道出油口相通必单独外接油箱
应 减压阀降低系统某支路油液压力系统中两压力回路常夹紧支路润滑支路电液动换阀控制回路需注意减压阀具压力损失分支油路油路压力低流量较时考虑采高低压泵分供油
三序阀
功 序阀功利液压系统中压力变化控制油路通断控制执行元件序动作
特点 结构序阀直动式先导式两种直动式序阀结构简单动作灵敏调定压力较低较高压力时宜采先导式序阀
根控制压力源序阀控式外控式分请注意两者图形符号区控式序阀进油路压力达设定压力前阀口直关闭达设定压力阀口开压力油进入油路外控式序阀阀口开闭油路进口压力关仅取决控制油路压力
序阀溢流阀区：（1）序阀出口负载油路相通时泄漏油先导控制油必须外泄溢流阀出口回油相通泄漏油先导控制油外泄泄（2）溢流阀进口压力限定阀调定压力序阀进口压力负载决定序阀开启负载增加进步升高
应 序阀途：（1）控制执行元件序动作（参见教材P126图7－31）（2）控式序阀作背压阀（3）单阀联组成衡阀锁定执行元件（参见教材P110图7－11）（4）外控序阀双泵供油系统卸荷（参见教材P123图7－25）
四压力继电器
压力继电器利液体压力信号控制电气触点通断液压电气转换元件油液压力达设定压力时压力继电器发出电信号控制电气元件动作实现执行元件序动作系统安全保护动作互锁
例题 图示ab回路参数相液压缸杆腔面积A＝50cm2负载FL＝10000N阀调定压力图示试分确定ab两回路活塞运动时活塞运动终端停止时AB两点压力
解：
1．a回路油泵溢流阀减压阀液压缸等元件组成
（1）活塞运动时
液压缸力衡方程
时B点压力未达减压阀设定压力减压阀阀口全开进出油口互通A点压力B点压力相等
（2）活塞终端停止时
活塞终端停止时减压阀出口输出油液出口压力2MPa升高调定压力够保持恒定时减压阀处工作状态
少量油液流减压阀外泄流回油箱油泵输出液压油开溢流阀返回油箱A点压力应等溢流阀调定压力
2．b回路油泵溢流阀序阀液压缸等元件组成
（1）活塞运动时
液压缸力衡方程
时A点压力应达序阀设定压力否序阀开
（2）活塞终端停止时
活塞终端停止时序阀出口输出油液出口压力快速升高序阀进口压力升高直油液开溢流阀返回油箱时B点A点压力等溢流阀调定压力
面出测题供参考请认真思考出结答案
测题 图示液压系统液压缸活塞面积A1＝A2＝100cm2缸Ⅰ负载FL＝35000N缸Ⅱ运动时负载零计摩擦阻力路损失溢流阀序阀减压阀调定压力分4MPa3MPa2MPa求列三种工况ABC处压力
（1）液压泵启动两换阀处中位
（2）1YA通电2YA断电液压缸运动时终端停止时
（3）1YA断电2YA通电液压缸运动时碰挡块停止时
参考答案
（1）pA＝pB＝4MPapC＝2MPa
（2）运动时 pA＝pB＝35MPapC＝2MPa 终端时pA＝pB＝4MPapC＝2MPa
（3）运动时 pA＝pB＝pC＝0 终端时pA＝pB＝4MPapC＝2MPa
请您删容O(∩_∩)O谢谢2015年中央电期末复考试抄全电期末考试必备抄电考试必抄请您删容O(∩_∩)O谢谢2015年中央电期末复考试抄全电期末考试必备抄电考试必抄The battle for young viewers CCTV is embracing Internet culture and working with independent producers on TV shows to woo audiences under 35 Han Bing bin reports After charming audiences with his warm smile for 14 years China Central Television host Li Jiaming recently found himself targeted by a group of young netizens unhappy with his style The complaints came after Li hosted the premiere of Rising Star on Oct 31 It is a singing competition show that originated in Israel Many young netizens found his hosting style slow and boring and mocked it as CCTV evening gala style They even initiated an online campaign to replace him The 40yearold host＇s reaction to the criticism was surprising During the second episode he jokingly called himself the slow Jiaming and acted much younger talking faster and louder It＇s like selling a product When the customers file a complaint you must change says Li In the Internet age you get feedback very quickly These young people are so cute When you＇re willing to change for them they will quickly like you back In order to win more young viewers CCTV is relying on programs such as Rising Star to embrace Internet culture In Rising Star a studio audience and fans watching on television vote for their favorite singers in real time using the instantmessaging app WeChat Rising Star was designed to be a live broadcast but the Chinese version isn＇t because of policy reasons Still WeChat votes by viewers at home are still a major factor in determining which contestants advance to the next round In the show＇s latest episode more than 65 million votes were cast via WeChat Now the competition among entertainment shows is very fierce Audiences have more diverse needs CCTV needs to embrace an open attitude interact with young audiences and blend with the Internet says Lyu Yitao director of CCTV＇s entertainment channel The producer of Rising Star Enlight Media says the program will have a phenomenal effect given CCTV＇s audience base nationwide But it comes with a challenge says Zhang Hang chief producer of the program and CEO of Enlight Media＇s TV business Unlike topranking provincial satellite channels such as Hunan TV which have a large base of young fans thanks to a series of phenomenally popular entertainment and reality shows CCTV productions are usually more conservative and serious and thus have a much older audience base If we were to run this program on Hunan we may attract twice as many viewers says Zhang But since we didn＇t make it there we now have to make the best out of the given conditions And it means we have to make certain compromises When the current season of Rising Star ends Zhang says his company will conduct an overall evaluation of the program and make adjustments for future seasons Although audience ratings haven＇t lived up to Zhang＇s expectations he says the program has already helped CCTV attract more young people According to Enlight Media the number of people ages 15 to 35 who watched the first episode of Rising Star was 76 percent higher than the usual audience for CCTV entertainment productions In order to attract young audiences CCTV has been working with independent production companies As one of CCTV＇s closest partners Enlight Media has produced several entertainment and reality shows for the company＇s channels including the Chinese version of The Biggest Loser on CCTV＇s business channel and an original teenager talent show Shaonian Zhongguo－qiang (Strong Young Chinese) on CCTV1 This year CCTV also licensed EEMedia the producer of the popular Super Girl talent shows to produce the talk show Hi 2014 hosted by Taiwan pop star Harlem Yu and one of China＇s most popular TV stars Xie Na The show is geared toward younger audiences Canxing Productions which rose to fame with the success of its Voice of China series on Zhejiang TV also produced two talent shows for CCTV One is an original production called Songs of China which ended up as one of CCTV＇s most watched programs of 2014 The State Administration of Press Publication Radio Film and Television announced earlier this year that starting in 2015 only one music talent show can be aired nationwide during prime time each season and there can be only one program based on foreign formats each year However domestic media report that such policies don＇t apply to CCTV meaning it will become a highly desired platform by production companies Wang Changtian CEO of Enlight Media confirmed to the Shanghai Securities News that its programs scheduled to air on CCTV next year which include at least two reality shows won＇t be affected A kung futhemed reality show produced by Canxing is also reportedly scheduled to run on CCTV next year CCTV is very active The level of its acceptance of new ideas is even beyond my imagination says Zhang Hang Our cooperation with CCTV will surely continue When winter comes nothing is more relaxing than a hot spring bath For thousands of years natural mineralrich hot spring baths have also been used to relieve health ailments The water found in natural hot springs contains a variety of different minerals and the most common one is sulfur It has a rotten egg smell but is excellent for skin The sulfurcontaining water might be just what the doctor ordered when it comes to relieving pain stress itchy skin arthritis and more Hot springs resorts are thriving as biting cold winter arrives Here we take a look at some of the best natural hot springs China has to offer
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液压传动国民济领域中应十分广泛专业液压机械工作求工况特点动作循环作液压机械部分液压系统满足液压机械项技术求系统构成工作原理采液压元件作特点等相教材中介绍YT4543型动力滑台注塑机船舶起货机等三种机械设备液压系统分析工作原理性特点试图通实例学者掌握分析液压系统般步骤方法实际液压系统较复杂读懂液压系统图非易事初学者说需通量读图分析循序渐进积累验逐步掌握分析液压系统般步骤方法面出例供学者参考：
例1．图示液压机械动作循环快进工进二工进快退停止读懂液压系统原理图分析系统中油液流动情况填写电磁铁动作序表说明系统特点
a1
a2
a1＞a2
注：图中a1 a2分阀7阀9节流口通流面积
（1）系统油液流动情况
快进
进油路 液压泵2――三位四通换阀4（左位）――液压缸杆腔
回油路 液压缸杆腔――二位二通阀10（左位）――三位四通换阀4（左位）――油箱
工进
进油路 液压泵2――三位四通换阀4（左位）――液压缸杆腔
回油路 液压缸杆腔――二位二通阀6（左位）――调速阀7――三位四通换阀4（左位）――油箱
二工进
进油路 液压泵2――三位四通换阀4（左位）――液压缸杆腔
回油路 液压缸杆腔――二位二通阀8（左位）――调速阀9――三位四通换阀4（左位）――油箱
快退
进油路 液压泵2――三位四通换阀4（右位）――液压缸杆腔
回油路 液压缸杆腔――三位四通换阀4（右位）――油箱
（2）电磁铁动作序表
电磁铁
动作
1DT
2DT
3DT
4DT
5DT
快进
－
＋
－
－
－
工进
－
＋
＋
－
＋
二工进
－
＋
－
＋
＋
快退
＋
－
－
－
－
停止
－
－
－
－
－
注：电磁铁吸合标＋电磁铁断开标－
（3）液压系统特点
液压系统调速回路属回油路节流调速回路液压系统速度换接回路采联调速阀二次进回路二位二通阀68互相切换时回油分通两通油截面调速阀返回油箱实现两种进速度
三位四通换阀中位机H型实现系统卸荷
例2．图示液压系统动作循环夹紧快进工进快退放松试读懂液压系统图说明油液流动情况完成液压系统动作循环表
夹紧 放松
（1）油液流动情况
夹紧
进油路 液压泵2――减压阀4――单阀5――二位四通阀6（左位）――液压缸9杆腔
回油路 液压缸9杆腔――二位四通阀6（左位）――油箱
快进
进油路 液压泵2 ――三位四通阀11（左位）――液压缸10杆腔
回油路 液压缸10杆腔――三位四通阀11（左位）――二位二通阀13（左位）――油箱
工进
进油路 液压泵2 ――三位四通阀11（左位）――液压缸10杆腔
回油路 液压缸10杆腔――三位四通阀11（左位）――调速阀12――油箱
快退
进油路 液压泵2――三位四通阀11（右位）――液压缸10杆腔
回油路 液压缸10杆腔――三位四通阀11（右位）――二位二通阀13（左位）――油箱
放松
进油路 液压泵2――减压阀4――单阀5――二位四通阀6（右位）――液压缸9杆腔
回油路 液压缸9杆腔――二位四通阀6（右位）――油箱
（2）系统动作循环表
电磁铁
动作
1DT
2DT
3DT
4DT
缸9夹紧
－
－
－
＋
缸10快进
＋
－
－
＋
缸10工进
＋
－
＋
＋
缸10快退
－
＋
－
－
缸9松开
＋
－
＋
－
停止
－
－
－
－
注：电磁铁吸合标＋电磁铁断开标－
面题请学行完成
题 图示液压系统动作循环快进工进二工进快退试读懂液压系统图说明油液流动情况完成液压系统动作循环表
注：a1a2分调速阀78通油面积
液压系统应分析（2）
液压系统应分析（1）中讲实际液压系统较复杂读懂液压系统图非易事初学者说需通量读图分析循序渐进积累验逐步掌握分析液压系统般步骤方法面出例供学者参考：
例题 动作循环表说明阅读图示液压系统原理图说明系统动作油液流动状况完成电气元件动作循环表分析系统特点
动作名称
电气元件
1YA
2YA
11YA
12YA
21YA
22YA
YJ
定位夹紧
快进
工进卸荷
快退
松开拔销
原位卸荷
备注：（1）ⅠⅡ两回路进行独立循环动作互约束
（2）12YA22YA中通电时1YA便通电12YA22YA均断电时1YA断电
系统供油回路定位夹紧回路工作油路Ⅰ工作油路Ⅱ组成ⅠⅡ两回路进行独立循环动作互约束动作序表列
油路Ⅰ油液流动情况
1．定位夹紧
定位缸定位：
进油路线：高压流量泵→减压阀→单阀→2位4通换阀（左位）→定位缸
杆腔
回油路线：定位缸杆腔→2位4通换阀左位→节流阀→油箱
夹紧缸夹紧：
进油路线：高压流量泵→减压阀→2位4通换阀（左位）→序阀→夹紧缸杆腔
回油路线：夹紧缸杆腔→2位4通换阀（左位）→节流阀→油箱
夹紧工件进油路压力升高压力继电器（YJ）动作发信号1YA11YA12YA通电启动油路Ⅰ（1YA21YA22YA通电启动油路Ⅱ缸Ⅱ快进）
2．快进 1YA通电11YA12YA通电
进油路线：低压流量泵→2位5通换阀右位→缸Ⅰ杆腔
回油路线：缸Ⅰ杆腔→2位3通换阀左位→2位5通换阀右位→缸Ⅰ杆腔
泵输出油液缸Ⅰ两腔互通形成差动连接实现快速运动
3．工进卸荷（低） 1YA断电12YA断电11YA通电
进油路线：高压流量泵→2位5通换阀左位→2位3通换阀左→缸Ⅰ杆腔
回油路线：缸Ⅰ杆腔→调速阀→油箱
实现工进速度调速阀调节属回油路节流调速1YA断电先导式溢流阀
荷口通油箱低压流量泵溢流阀荷
4．快退 1YA通电12YA通电11YA断电
进油路线：低压流量泵→2位5通换阀右位→缸（Ⅰ）杆腔
回油路线：缸（Ⅰ）杆腔→2位3通换阀右位→油箱
实现快速退回
5松开拔销 2YA通电1YA断电
进油路线：高压流量泵→减压阀→单阀→2位4通换阀右位→时定位
夹紧缸杆腔相通
回油路线：夹紧缸杆腔→单序阀中单阀→
（合流）——
定位缸杆腔 ———————————→
→2位4通换阀右位→节流阀→油箱
6 原位卸荷（低） 电器元件均断电处图示状态
二 油路Ⅱ油液流动情况
定位夹紧油路Ⅰ完全相仅分析快进工进快退
1．定位夹紧 油路Ⅰ
2．快进： 1YA通电21YA通电22YA通电
进油路线：低压流量泵→2位5通换阀右位→2位3通换阀左位→缸Ⅱ杆腔
回油路线：缸Ⅱ杆腔→2位5通换阀右位→2位3通换阀左位→缸Ⅱ杆腔
泵输出油液缸Ⅱ两腔互通实现差动连接实现快速进运动
3．工进卸荷（低） 21YA通电22YA断电1YA断电
进油路线：高压流量泵→调速阀→2位3通换阀左位→缸Ⅱ杆腔
回油路线：缸Ⅱ杆腔→2位5通换阀左位→单阀→油箱
调速阀调节工进速度属进油路节流调速回路单阀回油路建立背压工进速度稳定低压流量泵卸荷油路Ⅰ
4快退 1YA通电22YA通电21YA断电
进油路线：低压流量泵→2位5通换阀右位→缸（Ⅱ）杆腔
回油路线：缸（Ⅱ）杆腔→2位3通换阀右位→油箱
电器元件动作表
动作名称
电器元件
1YA
2YA
11YA
12YA
21YA
22YA
YJ
定位夹紧
－
－
－
－
－
－
+
快进
+
－
+
+
+
+
（+）
工进卸荷（低）
－
－
+
－
+
－
（+）
快退
+
－
－
+
－
+
（+）
松开拔销
－
+
－
－
－
－
－
原位卸荷（低）
－
－
－
－
－
－
－
三 系统特点
1．分析知回路ⅠⅡ独立互干扰实现工件加工求扩加工范围
2．快进快退两回路均低压流量泵供油快进时均差动连接提高快进速度
3．工进时低压流量泵卸荷节省源减少油液发热
4．调速回路均节流调速回路Ⅰ回油节流调速回路Ⅱ进油节流调速回油路加背压保证工进速度稳定
5．快进快退时高压流量泵卸荷功率损失
液压系统中压力控制阀
液压系统中压力控制阀调定系统回路分支回路压力功分类常压力控制阀溢流阀减压阀序阀压力继电器等压力控制阀结构相似性差系统中作相搞清区联系学压力控制回路液压系统分析非常重
溢流阀
功 溢流阀功通阀口溢流控系统回路压力保持稳定实现稳压调压限压作
特点 结构溢流阀直动式先导式两种直动式溢流阀压力较高流量较时求调压弹簧刚度调节性较差滑阀泄漏高压控制难实现低压流量场合先导式溢流阀特点先导阀控制阀溢流阀阀溢流时溢流阀进口压力维持先导阀弹簧调定定值先导式溢流阀特点具远程控制口方便实现系统卸荷远程调压
溢流阀泄漏油流先导阀油液返回油箱时泄外泄两种方式泄时泄漏油流弹簧腔先导阀弹簧腔通阀体连接通道出油口相通外泄时泄漏油流先导阀油液直接单独引回油箱
应 溢流阀途：（1）定量泵出口联溢流阀调节泵出口压力（2）变量泵出口联溢流阀系统起载保护作（3）回油路接入直动式溢流阀执行元件运动稳（4）利先导式溢流阀远程控制口实现系统卸荷远程调压总系统中溢流阀作溢流阀安全阀背压阀调节系统压力系统卸荷
二减压阀
功 减压阀功流减压阀油液压力降低减压阀出口连接回路压力保持稳定减压阀出口压力维持恒定受进口压力通流量影响
特点 结构减压阀直动式先导式两种分场合
减压阀阀心处原始位置时阀口开阀进出口沟通阀心出口处压力控制出口压力未达调定压力时阀口全开阀心动出口压力达调定压力时阀心移阀口关调定压力达衡减压阀出口处输出油液时出口压力够基保持恒定时少量油液先导阀流回油箱
减压阀溢流阀区：（1）减压阀保持出口处压力基变溢流阀保持进口处压力基变（2）工作时减压阀进出油口互通溢流阀进出油口通（3）减压阀求外泄先导阀弹簧腔需通泄油口单独外接油箱溢流阀允许泄先导阀弹簧腔通阀体连接通道出油口相通必单独外接油箱
应 减压阀降低系统某支路油液压力系统中两压力回路常夹紧支路润滑支路电液动换阀控制回路需注意减压阀具压力损失分支油路油路压力低流量较时考虑采高低压泵分供油
三序阀
功 序阀功利液压系统中压力变化控制油路通断控制执行元件序动作
特点 结构序阀直动式先导式两种直动式序阀结构简单动作灵敏调定压力较低较高压力时宜采先导式序阀
根控制压力源序阀控式外控式分请注意两者图形符号区控式序阀进油路压力达设定压力前阀口直关闭达设定压力阀口开压力油进入油路外控式序阀阀口开闭油路进口压力关仅取决控制油路压力
序阀溢流阀区：（1）序阀出口负载油路相通时泄漏油先导控制油必须外泄溢流阀出口回油相通泄漏油先导控制油外泄泄（2）溢流阀进口压力限定阀调定压力序阀进口压力负载决定序阀开启负载增加进步升高
应 序阀途：（1）控制执行元件序动作（参见教材P126图7－31）（2）控式序阀作背压阀（3）单阀联组成衡阀锁定执行元件（参见教材P110图7－11）（4）外控序阀双泵供油系统卸荷（参见教材P123图7－25）
四压力继电器
压力继电器利液体压力信号控制电气触点通断液压电气转换元件油液压力达设定压力时压力继电器发出电信号控制电气元件动作实现执行元件序动作系统安全保护动作互锁
例题 图示ab回路参数相液压缸杆腔面积A＝50cm2负载FL＝10000N阀调定压力图示试分确定ab两回路活塞运动时活塞运动终端停止时AB两点压力
解：
1．a回路油泵溢流阀减压阀液压缸等元件组成
（1）活塞运动时
液压缸力衡方程
时B点压力未达减压阀设定压力减压阀阀口全开进出油口互通A点压力B点压力相等
（2）活塞终端停止时
活塞终端停止时减压阀出口输出油液出口压力2MPa升高调定压力够保持恒定时减压阀处工作状态
少量油液流减压阀外泄流回油箱油泵输出液压油开溢流阀返回油箱A点压力应等溢流阀调定压力
2．b回路油泵溢流阀序阀液压缸等元件组成
（1）活塞运动时
液压缸力衡方程
时A点压力应达序阀设定压力否序阀开
（2）活塞终端停止时
活塞终端停止时序阀出口输出油液出口压力快速升高序阀进口压力升高直油液开溢流阀返回油箱时B点A点压力等溢流阀调定压力
面出测题供参考请认真思考出结答案
测题 图示液压系统液压缸活塞面积A1＝A2＝100cm2缸Ⅰ负载FL＝35000N缸Ⅱ运动时负载零计摩擦阻力路损失溢流阀序阀减压阀调定压力分4MPa3MPa2MPa求列三种工况ABC处压力
（1）液压泵启动两换阀处中位
（2）1YA通电2YA断电液压缸运动时终端停止时
（3）1YA断电2YA通电液压缸运动时碰挡块停止时
参考答案
（1）pA＝pB＝4MPapC＝2MPa
（2）运动时 pA＝pB＝35MPapC＝2MPa 终端时pA＝pB＝4MPapC＝2MPa
（3）运动时 pA＝pB＝pC＝0 终端时pA＝pB＝4MPapC＝2MPa
请您删容O(∩_∩)O谢谢2015年中央电期末复考试抄全电期末考试必备抄电考试必抄请您删容O(∩_∩)O谢谢2015年中央电期末复考试抄全电期末考试必备抄电考试必抄The battle for young viewers CCTV is embracing Internet culture and working with independent producers on TV shows to woo audiences under 35 Han Bing bin reports After charming audiences with his warm smile for 14 years China Central Television host Li Jiaming recently found himself targeted by a group of young netizens unhappy with his style The complaints came after Li hosted the premiere of Rising Star on Oct 31 It is a singing competition show that originated in Israel Many young netizens found his hosting style slow and boring and mocked it as CCTV evening gala style They even initiated an online campaign to replace him The 40yearold host＇s reaction to the criticism was surprising During the second episode he jokingly called himself the slow Jiaming and acted much younger talking faster and louder It＇s like selling a product When the customers file a complaint you must change says Li In the Internet age you get feedback very quickly These young people are so cute When you＇re willing to change for them they will quickly like you back In order to win more young viewers CCTV is relying on programs such as Rising Star to embrace Internet culture In Rising Star a studio audience and fans watching on television vote for their favorite singers in real time using the instantmessaging app WeChat Rising Star was designed to be a live broadcast but the Chinese version isn＇t because of policy reasons Still WeChat votes by viewers at home are still a major factor in determining which contestants advance to the next round In the show＇s latest episode more than 65 million votes were cast via WeChat Now the competition among entertainment shows is very fierce Audiences have more diverse needs CCTV needs to embrace an open attitude interact with young audiences and blend with the Internet says Lyu Yitao director of CCTV＇s entertainment channel The producer of Rising Star Enlight Media says the program will have a phenomenal effect given CCTV＇s audience base nationwide But it comes with a challenge says Zhang Hang chief producer of the program and CEO of Enlight Media＇s TV business Unlike topranking provincial satellite channels such as Hunan TV which have a large base of young fans thanks to a series of phenomenally popular entertainment and reality shows CCTV productions are usually more conservative and serious and thus have a much older audience base If we were to run this program on Hunan we may attract twice as many viewers says Zhang But since we didn＇t make it there we now have to make the best out of the given conditions And it means we have to make certain compromises When the current season of Rising Star ends Zhang says his company will conduct an overall evaluation of the program and make adjustments for future seasons Although audience ratings haven＇t lived up to Zhang＇s expectations he says the program has already helped CCTV attract more young people According to Enlight Media the number of people ages 15 to 35 who watched the first episode of Rising Star was 76 percent higher than the usual audience for CCTV entertainment productions In order to attract young audiences CCTV has been working with independent production companies As one of CCTV＇s closest partners Enlight Media has produced several entertainment and reality shows for the company＇s channels including the Chinese version of The Biggest Loser on CCTV＇s business channel and an original teenager talent show Shaonian Zhongguo－qiang (Strong Young Chinese) on CCTV1 This year CCTV also licensed EEMedia the producer of the popular Super Girl talent shows to produce the talk show Hi 2014 hosted by Taiwan pop star Harlem Yu and one of China＇s most popular TV stars Xie Na The show is geared toward younger audiences Canxing Productions which rose to fame with the success of its Voice of China series on Zhejiang TV also produced two talent shows for CCTV One is an original production called Songs of China which ended up as one of CCTV＇s most watched programs of 2014 The State Administration of Press Publication Radio Film and Television announced earlier this year that starting in 2015 only one music talent show can be aired nationwide during prime time each season and there can be only one program based on foreign formats each year However domestic media report that such policies don＇t apply to CCTV meaning it will become a highly desired platform by production companies Wang Changtian CEO of Enlight Media confirmed to the Shanghai Securities News that its programs scheduled to air on CCTV next year which include at least two reality shows won＇t be affected A kung futhemed reality show produced by Canxing is also reportedly scheduled to run on CCTV next year CCTV is very active The level of its acceptance of new ideas is even beyond my imagination says Zhang Hang Our cooperation with CCTV will surely continue When winter comes nothing is more relaxing than a hot spring bath For thousands of years natural mineralrich hot spring baths have also been used to relieve health ailments The water found in natural hot springs contains a variety of different minerals and the most common one is sulfur It has a rotten egg smell but is excellent for skin The sulfurcontaining water might be just what the doctor ordered when it comes to relieving pain stress itchy skin arthritis and more Hot springs resorts are thriving as biting cold winter arrives Here we take a look at some of the best natural hot springs China has to offer
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