A8V - 58 hd plunger pump overhaul

1. The dismantling basis

In maintenance and dismantling A8V - 58 hd plunger pump before, should first P - Q curve of the pump (pressure - flow curve). Decreased by more than 10% if its power or reduced by more than 25%, with rated load flow is required for maintenance. In addition, can also according to determine whether the need for maintenance operation time, generally the host running to 6 ~ 7 000 000 h to overhaul the hydraulic pump.

2. Repair parts

(1) the valve plate and the plunger cylinder fitting surface

Spherical valve disc is to change or repair after wear, depending on valve plate material strength, performance, can maintain the hydraulic pump overhaul period. If the valve plate and the plunger cylinder fitting surface wear is around 0.02 mm or spherical with uneven, available spherical grinding machine grinding. If no ball mill, also can do spherical grinding block grinding, can also be used M10 alumina abrasives manual grinding, then two component matching grinding, the grinding quantity sum shall not be more than 0.3 mm.

When the valve plate and the plunger cylinder fitting surface integral wear is more than 0.3 mm, can use first brush plating method to restore flow table size, matching grinding to standard size. When the valve plate and the plunger cylinder fitting surface wear is more than 0.5 mm and scratches overall deep, you can use the tico brand TG919 conductive repair glue to fill scratches and grinding smooth, brush plating, matching grinding to standard size.

Detection with flow plate, not only to detect the surface size and amount of wear and tear, still must for flaw detection. As it is to found the valve plate for internal defect detection, it must be replaced a new one.

(2) with plunger piston hole

With plunger piston hole of fit clearance should not be longer than 12 (including m, roundness and cylindricity shall not be greater than 5 (including m, if more than standard, the repair is required.

Plunger hole wear not serious, available match M10 alumina abrasives abrasive grinding rod, eliminate the roundness and cylindricity error; Such as plunger hole deep scratches strain, usable brush plating or cold glue coating repair. If the roundness and cylindricity error of plunger exceeds standard, can grinding first, then use the brush plating or cold glue coating repair. With plunger piston hole after repair, mutual also with engine oil.

(3) piston sliding boots and sliding boots sphere

Plunger sliding boots with sliding boots fitting clearance of spherical limit of 0.05 mm, if both wear quantity is not big, usable brush plating process back to a certain size, mutual cooperate again.

The maintenance of the servo valve (4) variables

If the hydraulic pump output performance degradation, and adjust the adjusting screw lose, explanatory variable servo valve doesn't work. At this time should be disassembled variable servo valve, wash every part with kerosene, again with the valve core of super fine sand paper burnish fit place, and then use grinding rod with chrome oxide abrasive lapping flat valve hole strain, finally to grind the valve core and valve hole with oil.

3. The detection and adjustment

(1) rotary component testing and adjusting

Hydraulic pump each component after repair, when the assembly to the rotating components (2 sets of valve plate, piston cylinder, etc.) for testing and adjusting. Such as values outside of the tolerance 0.04 mm, can be adjusted by using the method of addition, subtraction gasket axial clearance.

(2) assembly and performance testing

Hydraulic pump assembly, all the fixed bolt to blot out the no. 221 is too solid glue. After assembling, the hydraulic pump test-bed for performance testing. If there is no hydraulic pump test rig, hydraulic pump can be installed back to the machine, connected to the hydraulic tester for testing. On the standard curve of P - Q take 5 sets of data, according to each group of data of hydraulic pump load respectively, P is then measured data and standard data contrast each Q. If there are any differences, adjusted by hydraulic pump regulator, until each group P - Q data with basic close to standard data.