The advantages and disadvantages of modifying key components of hydraulic excavator pumps and valves

Regular maintenance and warranty are the foundation for the smooth operation of mechanical equipment. To ensure that excavators can continuously and stably meet production demands, it is not only necessary to strictly follow the usage and maintenance requirements and regulations of the equipment and carry out daily maintenance, but also to adopt a mandatory maintenance system that emphasizes prevention and warranty to better guarantee the efficiency and service life of the equipment.

However, due to the high maintenance costs of some equipment, along with various reasons such as inconvenient maintenance, difficulty in finding spare parts, and severe aging and wear, some machinery has fallen into disrepair over time and can only be put back into use after processing and transformation, such as PC200-6 (95), EX-2/3, etc. Wang Yongfu of Hunan Japan-South Korea Hydraulic conducted an analysis of the pros and cons of the transformation of such machinery, hoping to provide some reference for his peers.

PC200-6 (95

Most models will experience performance failures of the hoist after long-term operation for a period of time, such as the back machine or inability to increase the speed. Since the hoist does not come with factory parts and the genuine factory sales price is 15,500 yuan per piece, many mechanical business owners, considering the cost, can only choose to modify it.

Advantages: The current modified K3V112 pump and the modified valve block are affordable.

Disadvantages: The modified machinery has poor operational sensitivity and sluggish variable response, failing to meet the requirements of mechanical production. It has high requirements for the LS feedback system of the distribution valve and is ineffective for fine-tuning the engine control (it can only operate when the throttle reaches seven or eight steps). So there has been no extensive modification for this type of model.

2. EX-2/3 electronic control to hydraulic control

This type of model has a complex electrical control system. As time goes by and it is used for a long time, the circuits age over time, the sensitivity drops significantly, and the mechanical parts often experience slow speed and backloading. At present, most users require modification.

Advantages: The price of the electro-liquid conversion is moderate

Disadvantages: The operation response is slow after the transformation. It is recommended to modify the LS system of the distribution valve.

3. Modification of the EX-2/3 pump valve assembly

Two-thirds of Hitachi's machines have problems with the distribution valves, while the pumps are relatively easy to repair, so there are not many cases where only the pumps are modified.

Advantages: The pump uses K3V112, and the valve uses Toshiba (HD700-7 or R200-5). After modification, the mechanical performance is improved, and the price is moderate. This kind of modification is suitable for machinery with damaged parts due to fire or overturning.

Disadvantage: The composite performance is slightly poor.

4. Dongfanghong 100, Xuwa 80, Yuchai 80, etc

The original pump is Toshiba PV92. It is difficult to keep up with the supply and the spare parts are expensive.

If it is an 80-unit K3V112 single pump, shorten the thick spring in the hoist (which controls the flow rate in the low-pressure area) by approximately 2.5mm to 3mm. If it is adjusted on the test bench again, the effect will be better when it is debugged on the machine.