附 录
附录A
Understanding of concrete pump hydraulic system Pumping Hydraulic system Boom hydraulic system Outrigger hydraulic system Hydraulic system diagram
Daily check and maintenance of the hydraulic system
The functions of the truck mounted concrete pump, hydraulic system can be divided into pumping hydraulic system, boom hydraulic system, outrigger hydraulic system.
Pumping Hydraulic system Is divided into three parts: main pumping system, distribution and lubricating system, mixing and cooling and cleaning system.
Main pumping system
There are two hydraulic loops: open and close loop.
The Open loop: uses an A11VLO190 variable displacement of axial piston pump. It is fitted with a constant power control device, pressure cut-off valve and electrical
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stroke limiter with proportional solenoid. The constant power control device has been set in the factory. The displacement can be
adjusted from 0 to Maximum by turning the
oil pump displacement potentiometer on the control panel from low to high.
Fig. 1 A11VLO 190
A，B Service port (without charging pump) 420 bar S Suction port (with charging pump) 35 bar
T1, T2 Air bleed, tank R Air bleed, oil drain
M1 Measuring point, regulating chamber M Measuring point, service port
G Port for positioning pressure (controller) for version with stroke limiter (H.., U2), HD and EP with screwed fitting GE10 – PLM (otherwise port G closed)
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The other is the control line, which can change the flow direction and the displacement of main pump through constant power valve,
proportional solenoid pressure reducing valve, directional control valve and servo valve of main pump.
The Closed loop: There is an auxiliary pump with relief valve that the setting pressure is 3.5Mpa in A4VG180. The auxiliary pump has two
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output ways. One is the charge oil line, which connects with suction line of main pump through the check valve in two pressure relief valves and add oil to main pump. At the same time excessive hydraulic oil return to oil tank through flushing valve and cooler to realize heat exchange for closed loop.
A, B Service line ports SAE 1 1/4\high pressure series 420 bar
T1 Case drain or filling port T2 Case drain M33×2; 18 deep MA, MB Pressure gauge - operating pressure A, B R Air bleed S Boost suction port
X1, X2 Control pressure ports (before the orifice) G Pressure port for auxiliary circuit PS Control pressure supply Fa Filter outlet
Fa1 Filter outlet (filter assembly) Fe Filter inlet M33×2; 18 deep FS Port from filter to suction line (cold start) MH Port for balanced high pressure
Y1, Y2 Remote control ports (only for HD control)
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Flushing valve
Used for closed loop to prevent excessive heat build-up in closed circuit operation. The setting pressure of flushing valve is 3.0MPa
Pressure reducing valve with proportional solenoid
Used for closed loop. The Output pressure is connected with the remote control port of main pump to control the displacement and is controlled by a proportional current signal and constant power valve. The displacement can be adjusted from 0 to Maximum by turning the displacement adjusting potentiometer.
Constant power valve
Used for closed loop. When the hydraulic system pressure is over the setting pressure, the valve works to reduce the output pressure of the
pressure reducing valve and maintain the constant power. Power setting
Fig.3 Constant power valve Main pump suction filter Pilot pressure setting 5
Open loop: filtration fineness 100u. Close loop: filtration fineness 20u.
When the indicator in the vacuum gauge exceeds the safe area or the electric signal instrument gives a warning, the cartridge may be blocked. It should be clean or replace filter cartridge promptly.
Filter filtration fineness is 20u in open loop. When the reading pressure of the vacuum gauge exceeds 0.35Mpa, the cartridge may be blocked. It should be clean or
Return filter
replace filter cartridge promptly.
Filter filtration fineness is 10u in closed loop. When the electricity deliver reports to the police, the cartridge may be blocked, it should be clean or replace filter cartridge promptly.
Distribution and lubricating system Constant pressure pump
Setting screw for pressure control zero /Stroke pressure
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Fig.4 Constant pressure pump
An A10VO28 constant pump is used for the distribution system of supply oil.
The setting of the pressure control valve of the pump is 16Mpa. Once the system pressure is reached, the bump will keep this pressure then decrease the displacement. There is a pressure relief valve in the distribution circuit to act as a safety valve, which is set to 18Mpa.
Plate ball valve (shut-off valve)
Used to discharge the accumulator. It must be rotated the lever of shut-off valve anti-clockwise when the pumping finishes or stopped for maintenance, in order to discharge the pressure of theaccumulator. (Pressure gauge of distribution system is zero)
Accumulator
Inflation pressure is 8-9Mpa. Use Only Nitrogen to fill the accumulator. Charging pressure should not exceed these figures.
Lubricating system
There are two types. One is reciprocating centralized lubrication that
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is driven by oil from the swing cylinders of distribution system includes lubricating single pump (or double pump), distributor, damper and filter. The other is automatic centralized lubrication that is driven by a D.C motor with an independent grease tank and independent from the hydraulic system. The interval time of lubrication is carried out in the factory. The lubrication system works automatically when pumping.
Mixing, cooling, cleaning system
Only the Mixing, cooling, cleaning system are driven by motor in open loop.
Gear pump
Gear pump supplies oil to the mixing, cooling, cleaning system. Sandwich type relief valve The pressure is set to 14Mpa. Ressure relay
If the mixing blade is stuck, the system pressure will raise. When the pressure exceeds the setting value (usually 10Mpa), the pressure relay will give a warning. The Solenoid directional control valve changes direction to let the mixing motor to rotate anti-clockwise. After 6 second the solenoid valve will reset, and the mixing motor will rotate clockwise again.
Return filter
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The filtration fineness is 10u in closed loop. The cartridge may be blocked when the electric alarm sounds. It should be replace promptly.
Boom hydraulic system Boom pump
Boom and outrigger use the same pump.
37m and 40m truck mounted concrete pumps: A2FO23 fixed displacement pump
44m and 47m truck mounted concrete pumps: A7VO55LRDS variable displacement pump, or A7VO55DRS variable displacement pump
46m and 49m truck mounted concrete pumps: A7VO55LRDS variable displacement pump
Fig.5 A7VO55DRS Fig.6 A7VO55LRDS Fig.7 A2FO23
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Boom proportional directional spool valve
The proportional directional spool valve with electro-hydraulic consists of pressure relief valve, pressure reducing valve, and flow control valve, and can be
controlled manual or by remote control.
Fig.8 Boom proportional directional spool valve Load-holding valve
Load-holding valve has three functions. (1) It acts as a lock when the cylinder isn’t moving. (2) Load-holding valve has twice relief function to protect boom against vibrating. It will be adjusted in the factory. (3) When the boom moves downward as
Slewing load-holding valve
gravity load, it can limit speed to prevent the boom falling too
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quickly and shaking.
There are three main functions. Lock, overload protection and speed limiting.
Outrigger hydraulic system
Outrigger hydraulic system and boom hydraulic system are used the same pump to supply oil. Outriggers should be set up before the boom is operated by the control levers or electric control button on both sides of the truck mounted concrete pump.
Outrigger proportional directional spool valve
It is an integrated unit with a relief valve inside to control maximum pressure of the outrigger hydraulic system.
Pressure relief
valve
Fig .9 Outrigger proportional directional spool valve Outrigger hydraulic lock
It is used to lock the outrigger cylinders and pay attention to the vertical moving of the outrigger cylinder when working .
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附录B
混凝土泵车液压系统的认识
泵送单元液压系统 臂架液压系统 支腿液压系统 液压原理图
液压系统的日常保养及维护
泵车液压系统按泵车功能可划分为泵送单元液压系统、臂架液压系统、支腿液压系统。
泵送单元液压系统：泵送单元液压系统按功能可分为三大部分：主泵送油路系统；分配及润滑油泵驱动系统；搅拌、冷却、清洗油路系统。
主泵送油路系统 ：主泵送系统按油液循环方式分为开式液压回路和闭式液压回路两种。
开式液压回路：采用一个轴向变量柱塞泵，该泵带有恒功率控制装置、压力截流阀和电控变量控制阀，恒功率控制装置出厂时已设定好。电控面板上油泵排量按钮由小变大范围内调节时，主油泵排量在
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0～最大范围内变化。
A，B 工 作 油 口（不 带 升 压 泵）420bar S吸油 口（带 升 压 泵）35bar T1, T2 放气 口，油 箱 R放气 口，放 油 M1变 量 缸 测 压 口 M工 作 油 口 测 压 口 G控 制 压 力 油 口 对于 排 量可限制型（ H…U2 ）和HD、EP带 紧固 螺栓 GE10-PLM（其他情况下油口G堵住）
闭式液压回路：采用A4VG180双向周向变量柱塞泵，该泵带内置补油泵，补油溢流阀调定压力3.5 MPa，其出口油路可分为两路：第一路为补油油路，通过两高压溢流阀内的单向阀，始终与主泵吸油油路相通，对主泵送油路进行补油，同时多余的油液经冲洗阀、冷却器流回油箱，实现对闭式油路系统的热交换。
第二路为控制油路，经恒功率阀、电磁比例减压阀、换向阀及泵内伺服缸伺服阀，实现主泵的变量及液流流动方向的改变。
图2 油泵A4VG180
A, B 工作油口 SAE 11/4\" 高压系列 420bar
T1 壳体泄油或注油口 T2 壳体泄油口 M33×2，深18
MA, MB 压力表、工作压力A，B
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R 放气口 S 吸油口
X1, X2 控制压力口（在节流孔前） G 辅助回路压力口 PS 控制压力供油口 Fa 过滤器出口
Fa1 过滤器出口（装配过滤器） Fe 过滤器进口 M33×2，深18 FS 从过滤器到吸油管的接口（冷启动） MH 平衡高压油口
Y1, Y2 遥控口（仅对于HD控制）冲洗阀
仅用于闭式液压回路，用于实现闭式回路油液的交换。冲洗阀的设定压力为3.0 MPa 电磁比例减压阀
仅用于闭式液压回路，其出口压力接主油泵远程控制口，控制油泵排量。出口压力受比例电流及恒功率阀的控制。遥控器或电控柜面板上油泵排量旋钮由小变大范围内调节时，主油泵排量在0～最大范围内变化。
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恒功率阀仅用于闭式回路，当回路工作压力超过设定压力时，恒功
率阀起作用。
图3 恒功率阀
主泵吸油滤油器
开式回路：过滤精度为100μ 闭式回路：过滤精度为20μ
当真空表指示超出安全区或电发讯器报警时，滤芯可能堵塞，应及时清洗或更换。
回油滤油器
开式回路：过滤精度为20μ。当真空压力表超过0.35MPa时，滤芯可能堵塞，应及时清洗或更换。
闭式回路：回油过滤精度为10μ。电发讯器报警时，滤芯可能堵塞，应及时清洗或更换。
分配及润滑油泵驱动系统 恒压泵
分配系统采用A10VO28恒压泵供油，其自带的压力控制阀设定压力为16Mpa。
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用于零点压力设定的控制螺杆 报警压力 图4恒压泵
当系统压力达到设定压力时，泵保持设定压力不变，但油泵排量减小，仅供图4给执行元件所需流量。分配油路中另有溢流阀起安全阀作用，设定压力为18Mpa.
板式球阀：
板式球阀用于蓄能器卸荷，当泵送完毕和停机维修时，必须反时针旋转截止阀手柄，使蓄能器能压力油卸荷（分配阀压力表显示值应为零）。
蓄能器：
蓄能器充气压力8～9MPa， 蓄能器充入的只能是氮气，充气压力必须按规定要求。
润滑系统：
润滑系统有两种形式：
一种是往复柱塞式浓油泵润滑系统由润滑单泵（或润滑双泵）、递进式分油器、阻尼器和网式过滤器组成,驱动压力油从摆动缸油路中引出。
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另一种是电机旋转柱塞式集中润滑系统，独立接油箱，出厂时已设好润滑间隔时间，泵送一工作，润滑装置即自动工作。 搅拌、冷却、清洗油路系统：
开式系统只有搅拌、清洗油路，冷却器由电机带动。 齿轮泵搅拌、冷却、清洗油路系统均由齿轮泵供油。 叠加式溢流阀设定压力为14Mpa。 压力继电器：
当搅拌叶片卡死时，系统油压升高，超过设定值（一般为10MPa），压力继电器（开关）发讯，电磁换向阀换向，使搅拌马达反转。当反转一定时间（约6秒），电磁阀恢复原位，搅拌马达正转。 回油滤油器：
仅用于主泵油路为闭式回路的泵车，过滤精度为10μ，电发讯器报警时，滤芯可能堵塞，应及时更换。 臂架液压系统 臂架油泵
臂架与支腿采用同一个泵。 37m、40m泵车：A2FO23定量泵
44m、47m泵车：A7VO55LRDS变量泵或A7VO55DRS变量泵 46m、49m泵车：A7VO55LRDS变量泵
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图5 油泵A7VO55DRS 图6油泵A7VO55LRDS 图7 油泵A2FO23臂架多路阀
为电液比例多路阀，可以手动或遥控操作，其内集成了安全阀、减压阀、流量控制阀等。
图8 臂架
多路阀
平衡阀 ：具体结构各厂家的稍有不同，但作用一样：(1)油缸不运动时，起闭锁作用；(2)平衡阀带有二次溢流功能，臂架振动过大闭锁腔的油液将溢流释放，起到保护臂架的功能；二次溢流压力出厂时已调定，用户轻易不要动。(3)臂架向下运动（有重力载荷的作用下）时，起到限速作用，防止臂架自由下滑和抖动。
回转控制阀具体结构各厂家的也有不同，但作用一样,也起闭锁、过载保护、限速作用。 支腿液压系统
支腿液压系统与臂架液压系统采用同一油泵供油，经臂架多路阀提供给支腿液压系统。臂架需要展开时，必须先打开各支腿。操纵支腿时，通过位于泵车两侧的操纵手柄和电控按钮进行协调控制。臂架伸展时，严禁操纵支腿。
支腿多路阀为整体式结构。其内置溢流阀，控制支腿的最高压力。
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安 全 阀
图9 支腿多路阀
支腿液压锁支腿油缸闭锁用，工作中应注意观察垂直油缸的下沉量。
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