Construction machinery hydraulic piston pump use and maintenance

The hydraulic system efficiency of a construction machine depends mainly on the volumetric efficiency of the hydraulic pump. When the volumetric efficiency drops to 72%, routine maintenance, replacement of bearings and aged seals are required, and replacement or repair of friction pairs beyond the mating clearance is required Its performance has been restored. In this paper, direct-axis swash plate piston pump-based, describes its use and maintenance methods. By hydraulic pressure oil tank, each time you start the machine, you must wait for the hydraulic pressure box to reach the use of air pressure before operating machinery. If the pressure of the hydraulic tank is low, it will cause the pull-off phenomenon in the hydraulic pump and the slippery whip, which will cause abnormal wear of the return plate and the pressure plate in the pump body. The use of charge pump piston pump, use 3000h, the operator needs to check the plunger pump 1-2 times a day to check the hydraulic pump running sound is normal. If you find the hydraulic cylinder speed or boring car, you should disassemble the charge pump check, check the edge of the impeller scratches, internal gear pump clearance is too large. For self-priming piston pumps, the fluid in the hydraulic tank should not be lower than the lower limit of the oil standard, and a sufficient amount of hydraulic oil should be maintained. The higher the cleanliness of the hydraulic fluid, the longer the life of the hydraulic pump. 2 hydraulic pump bearing plunger pump is the most important part of the bearing, if the bearing appears clearance, you can not guarantee the hydraulic pump within the three pairs of normal friction pair, but also undermine the hydrostatic friction of each friction pair of oil film thickness, lower Piston pump bearing service life. According to information provided by the hydraulic pump manufacturer, bearing the average service life of 10000h, more than this value will need to replace the new port. Demolition of the bearings, there is no professional testing equipment can not detect the bearing clearance, only visual inspection, such as the roller surface scratches or discoloration, it must be replaced. In the replacement of bearings, bearings should pay attention to the original letters and models, most of the piston pump bearing load capacity of large bearings, it is best to buy the original manufacturer, the original specifications of the product, if the replacement of another brand, should consult the bearing experience Staff look-up table swap, the purpose is to maintain the bearing accuracy level and load capacity. 3 pairs of friction pair inspection and repair 3.1 Plunger rod and cylinder bore Table 1 for the replacement of the plunger pump parts (see Figure 1), when listed in the various types of clearance tolerance, according to the following method Repair: (1) cylinder inlaid copper sleeve, copper sleeve can be replaced by the method of repair. First set a set of plunger rod diameter trim to a uniform size, and then over 1000 # polished sandpaper outside diameter. Cylinder installation copper sleeve of three ways: (a) cylinder warm or copper sleeve low temperature cryogenic extrusion, interference assembly; (b) mining with Loctite adhesive assembly, which method we require copper jacket Diameter surface of the groove; (c) cylinder tapping, copper outer diameter of the thread, Tu Le Ta plastic, screw into the assembly. (2) The cylinder and the copper sleeve fused by means of sintering are as follows: (a) grind and repair the cylinder hole by using a grinding rod, manual or mechanical method; (b) re-boring the cylinder bore by using a coordinate boring machine; (c Reamer cylinder bore repair. (3) adopt "surface engineering technology", the method is as follows: (a) electroplating technology: a layer of hard chrome plating on the plunger surface; (b) electroplating technology: brushing wear- Thermal spraying or arc spraying or electrospraying: spraying high-carbon martensite wear-resistant material; (d) laser welding: welding high hardness wear-resistant alloy powder on the plunger surface.