小松挖掘机铲斗缸和左行走马达工作无力故障的排除与维修

小松挖掘机铲斗缸和左行走马达工作无力故障的排除与维修

Komatsu excavator bucket cylinder and remove the left running motor fault and repair work to

PC220-5型挖掘机工作8500h后出现铲斗缸和左行走马达工作无力的故障，但回转动作和右行走工作正常，其余动作略显迟缓。

PC220-5 type of excavator working 8500h after bucket cylinder and left walking motor weakness of the fault, but rotary motion and right walking normal work, other actions are a bit slow.

根据液压系统图分析可知，可能引起铲斗缸和左行走无力的原因有：

According to the hydraulic system diagram analysis, may cause the bucket cylinder and left because of inability to walk:

(1). 控制铲斗或控制左行走的先导油路故障。

(1). The control or control the bucket left running pilot circuit fault.

(2). 控制铲斗或控制左行走的控制阀芯卡死或严重磨损。

(2). Control the bucket or control the control of walking the left spool stuck or severe wear.

(3). 铲斗回路安全补油阀卡死。

(3). The bucket loop safety fill valve stuck.

(4). 铲斗缸、活塞或油封严重损坏。

(4). The bucket cylinder piston or oil seal, serious damage.

(5). 左行走马达故障或中央回转接头窜油严重。

(5). The left walking motor fault or central rotary joint serious oil leakage.

(6). 主卸荷阀卡死。

(6) the main unloading valve stuck.

(7). 后泵或其控制系统故障。

(7). After the pump or the control system failure.

由液压系统图可知，铲斗缸和左行走马达都是靠后泵单独供油的。由于铲斗缸和左行走马达同时出现工作无力，因此故障最可能出现在主卸荷阀或后泵及其控制系统上。将前泵、后泵的高压油管更换，然后试机后发现：铲斗缸和左行走马达工作正常，而相后回思索马达和右行走马达工作无力。由于说明铲斗缸和左边行走马达及伺服操纵系统工作正常，故障出在为铲斗缸和左行走马达单独供油的后泵或其控制系统。

By the hydraulic system figure, bucket cylinder and left running motor are separate oil supply by pump. Due to the bucket cylinder and left running motor and unable to work, so failure is most likely to appear in the main unloading valve or pump and its control system. Will pump before, after high pressure tubing pump replacement, then the test machine that bucket cylinder and left walking motor work normally, and to consider the right motor and walking motor unable to work. Because that bucket cylinder and walking on the left side of the motor and servo control system is normal, fault a bucket cylinder and left walking single motor oil pump and its control system.

先检查后泵的控制系统：

After the first check the pump control system:

(1). 由于前泵工作正常，证明前泵、后泵共用的控制先导泵和TVC阀工作正常。

(1). Because the pump is working properly, that before the pump, pump and TVC common control pilot valve after the pump is normal.

(2). 在NC阀出口处装一个量程为6MPa的压力表测量该处油压pi，（因CO阀出口压力没有测点），将CO阀调节螺栓紧2~4圈，发现pi上升，再将调节螺栓调回原位，pi下降到原来的压力。检测结果符合CO阀工作特性，说明CO阀工作正常。

(2). In the NC valve outlet installed a range for 6Mpa pressure meter to measure the oil pressure PI, for CO valve outlet pressure without a measuring point), CO valve adjusting bolt 4 rounds, found that Pi increased, the adjusting bolt to repatriate the in situ, PI decreased to the original pressure. The results meet the working characteristics of CO valve, CO valve normal work.

(3). 将NC阀调节螺栓调紧2~4圈，发现pi上升，再将调节螺栓调回原位，pi下降到原来的压力。检测结果符合NC阀工作特性，说明NC阀工作正常。

(3). The NC valve adjusting bolt tightening ring 2~4, found that Pi increased, the adjusting bolt back in situ, PI decreased to the original pressure. The results meet the working characteristics of NC valve, NC valve normal work.

(4). 拆检伺服阀时发现：回位弹簧无折断且弹性良好，连杆机构没有胶落，阀芯无卡滞和磨损现象，由此说明伺服机构工作正常。

(4). Demolition of the servo valve found: back spring break and good elasticity, linkage without glue down, spool card hysteresis and wear phenomena, which shows the servo mechanism.

由上述检查结果可知，后泵的控制系统工作正常，铲斗和左行走无力，只能是后泵本身故障引起的。

By the inspection results show that, after pump control system is working properly, the bucket and left too weak to walk, can only be caused by the fault of the pump itself.

拆下液压泵总成，经解剖检查发现：前泵各部分零件完好无损，后泵损坏较为严重，柱塞缸端面与配油盘接触的表面有明显的沟槽，柱塞缸端面有轻度拉伤，其余液压元件无明显的磨损现象。显然，后泵不能正常工作是因为柱塞缸与配油盘接触面严重磨损，并形成较多的沟槽，造成液压油严重泄漏，使油压建立不起来，从而导致由后泵单独供油的铲斗缸和左行走马达工作无力。

Remove hydraulic pump assembly, the anatomical examination revealed: before the pump parts intact, pump damage is more serious, the piston cylinder and the end surface of the swash plate contact surface has obvious groove, plunger cylinder face a mild strain and the other hydraulic components without obvious phenomenon of wear and tear. Obviously, after the pump can not work normally is because the plunger cylinder and swash plate contact face serious wear and tear, and the formation of more channels, causing hydraulic oil a serious leak, the pressure built up, resulting in separate pump oil bucket cylinder and left by the walking motor unable to work.

鉴于柱塞缸端面损伤不大而配油盘损坏严重，无法修复的情况，我们采用修磨柱塞缸端面和更换新配油盘的维修方案。用手工对研柱塞缸端面和配油盘，使其接触面积达到95%以上。将研磨好的柱塞缸和配油盘装配使用，挖掘机工作恢复正常，

In view of the plunger cylinder end damage small swash plate, seriously damaged, beyond repair, we adopt grinding plunger cylinder end and replaced with new oil pan of the maintenance program. Research on hand piston cylinder and swash plate end, the contact area of more than 95%. The good grinding piston cylinder and swash plate assembly, the excavator work returned to normal,

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