How to extend the service life of hydraulic piston pump?

How to extend the life of a hydraulic piston pump: The efficiency of a hydraulic system depends primarily on the volumetric efficiency of a hydraulic pump. When the volumetric efficiency drops to 72%, routine maintenance, replacement of bearings and aged seals, replacement or repair are required Beyond the friction with the gap, so that its performance has been restored. 1, hydraulic pump: Straight shaft swash plate piston pump is divided into two types of self-suction oil pressure type. Most of the pressure supply type hydraulic pump with air pressure tank, there are hydraulic pump itself with a charge pump to the hydraulic pump inlet to provide pressure oil. Self-priming oil pump self-priming oil capacity, no external oil supply. Hydraulic pressure oil tank, each time you start the machine, you must wait for the hydraulic pressure tank to reach the use of pressure, to operate the machine. 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. 2, For self-priming oil type plunger pump, the oil 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 kept. The higher the cleanliness of the hydraulic fluid, the longer the life of the hydraulic pump. 3, the most important component of the hydraulic pump piston pump bearing is the bearing, if the bearing appears clearance, you can not guarantee the internal hydraulic pump three pairs of normal wear vice, but also will destroy the friction of the hydrostatic support film thickness, Decrease the life of plunger pump bearings. 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. 4 pairs of friction pair inspection and repair: plunger rod and cylinder bore replacement parts according to the plunger pump parts, when the various parts of the gap tolerance can be repaired as follows: (1) cylinder inlay 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. (4) Cylinder hole copper-free sleeve cylinder material is mostly ductile iron, the cylinder wall to prepare amorphous film or coating. Because of this special material on the inner wall of the cylinder bore, it is possible to form a hard-hard paired friction pair. If you blindly grind the cylinder bore, the surface material inside the bore of the cylinder bore is removed and the more structural properties of the friction change. Was removed from the coating friction pair, if forced to use, the friction surface temperature will rise sharply, the plunger rod and cylinder bore binding 5, the plunger rod in addition to the preparation of a unique film coating, coating containing minus Wear + wear + lubrication function, this group of friction actually real or hard - soft match, once people change the coating, it also destroyed the friction pair of the best matching materials, repair these special plunger pump, it is necessary to send Professional repair shop. 6, slipper and swashplate Swashplate and swashplate friction is the most complex pair of swashplate piston pumps in the pair. Table 1 shows the clearance between the plunger rod and the ball socket (see Table 2). If the gap between the plunger and the shoe is out of tolerance, the high pressure oil in the plunger chamber will flow from the clearance between the ball head and the shoe In the leakage, slippery shoes and swash plate thinning, severe hydrostatic pressure caused by failure of the support, slipper and swash plate metal contact friction, slipper ablation off, plunger ball head scratched swashplate. Plunger rod ball head and sliding ball socket beyond the tolerance 1.5 times, it must be replaced in groups. Table 2 Piston rod and cylinder bore Plunger diameter φ16 φ20φ25φ30φ35φ40 Standard clearance 0.0150.0250.0250.0300.0350.040 Limit clearance 0.0400.0500.0600.0700.0800.090 Standard clearance 0.0100.0100.0150.0150.0200. 020 The limit clearance 0.300.300.300.350.350.35 7, the role of the swash plate After a period of time, the swash plate surface will appear concave phenomenon, before using the platform grinding, we should first measure the original size and plane hardness. Grinding, and then measure the amount of grinding is, such as within 0.18 plunger pump use without interference; if more than 0.2mm above, you should use nitriding method to maintain the thickness of the original nitride layer. 8, the swash plate plane is scraped out of the ball by the plunger groove, laser welding alloy powder can be used to repair. Laser cladding technology can not only ensure the bonding strength of the material, but also ensure the hardness of the filler material, and does not reduce the hardness of the surrounding tissue. Also Shun to adopt chromium welding rod for manual surfacing, welding of the swash plate plane to be re-heat treatment, the best nitriding furnace heat treatment. Regardless of the method used to repair the swashplate, you must restore the original dimensional accuracy, hardness and surface roughness. 9, with the flow plate and the cylinder with the repair of the distribution surface with a flat plate with a flow and spherical with the flow of two forms. Spherical with the flow of friction pair, the cylinder with flow surface scratches relatively shallow, by means of grinding repair; cylinder with flow grooves deep, should first use "surface engineering" means to fill the trench, and then grinding , Can not be blind grinding, to prevent copper thinning or leakage of steel base. Friction pair in the form of plane flow can be grinded on the platform with high accuracy. Before the grinding of the cylinder body and the valve plate, the total thickness dimension and the size that should be ground off should be measured before compensation to the adjusting mat. With a larger flow plate, the grinding should be re-heat treatment to ensure that hardened layer hardness. Piston Pump Parts Hardness Standard Plunger Rod Recommended Hardware HS84 Rod End Ball Recommended Hardness 10, the length of the plunger pump life, and the usual maintenance, the quantity and quality of hydraulic oil, oil cleanliness and so on. Avoid oil particles in the piston pump friction caused by wear and tear, but also to extend the effective life of the plunger pump. In the maintenance of replacement parts should try to use the original production of parts, these parts sometimes fake parts than other expensive, but the quality and stability is better, if the purchase of counterfeit parts cheaper prices in the short term seems to be saving costs, However, this poses a hidden danger, may also cause greater damage to the use of the plunger pump.

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