Gear pump common troubleshooting methods (a)

At present, CB-B gear pump in the dump truck and construction machinery operating mechanism used more, now its common failures and troubleshooting are described below, for reference. 1, the reasons for the vibration and noise generated and excluded (1) inhaled air ① CB-B gear pump body and both sides of the cover for direct contact with the hard seal, if the contact surface flatness does not meet the requirements, the pump Easy to breathe in the air at work; also, the direct contact between the end cap of the pump and the gland, the air is also easy to invade; if the gland is a plastic product, due to its damage or deformation due to temperature changes, it will make the seal Strictly into the air. The way to get rid of this kind of trouble is: When the flatness of the pump body or pump cover can not meet the stipulated requirements, it can be grinded back and forth on the flat steel with the "8" shaped route with the gold sand, or on the surface grinder , So that its flatness does not exceed 5μm, and the need to ensure that the plane and the hole perpendicularity requirements; For the pump cover and gland at the leak, can be coated with epoxy adhesive sealing. ② The shaft is generally sealed with a skeleton oil seal. If the locking lip spring off, or the oil seal installed, or its lips were injured, aging, will make the back end of the seal often in negative pressure and inhale the air, the general can replace the new seal to be resolved. ③ fuel tank is not enough oil, or the suction nozzle is not inserted below the oil surface, the pump will inhale the air, this time should be added to the fuel tank to the oil line; if the oil return pipe mouth exposed oil, and sometimes because of Negative pressure within the system so that the air back into the system of irrigation, so return pipe mouth generally should be inserted below the oil level. ④ pump installation location is too high from the oil surface, especially in the pump speed is reduced, because the pump can not guarantee the necessary vacuum caused by insufficient suction and inhaled air. At this point should be adjusted to the relative height of the pump and oil surface to meet the requirements. ⑤ oil filter is clogged with dirt or its capacity is too small, resulting in increased suction resistance and inhalation of air; In addition, into the port of a larger caliber may also be brought into the air. At this point, you can clean the filter, or choose a larger capacity, and out of the appropriate diameter filter. In this way, not only can prevent the inhalation of air, but also to prevent noise. (2) Mechanical reasons (1) The connection between the pump and the coupling generates vibration and noise due to the non-compliance requirements. Should be required to adjust the coupling. ② due to dirt in the oil into the pump gear and other components caused by wear and tear and noise. Should replace the oil, strengthen the filter, open the pump cleaning; serious wear and tear of the gear, to be repaired or replaced. ③ parts pump damage or serious wear and tear will have vibration and noise: such as the tooth or the pitch error of large errors, poor contact between the two gears, tooth surface roughness, overhang length of the common law, the tooth backlash is too small, two meshing gear The contact area is not in the sub-round position. At this point, you can change the gear or the gear on the ground. At the same time, the bearing needle cage damage, the length of the shaft journal and needle wear, etc., can lead to poor bearing rotation and mechanical noise, this need to disassemble the gear pump, needle roller bearings replacement. ④ gear assembly gap is too small; gear end face and the front and rear end cover between the sliding surface due to the gear before the burr can not be carefully removed, thus running the joint surface injury, so that the internal leakage, leading to reduced output flow; The dirt enters the pump and wedges into the gap between the end face of the gear and the front and back end caps to strain the mating face, resulting in the communication of the high and low pressure cavities due to the radial tensioned groove, so that the output flow rate is reduced. The above measures should be used to repair the following measures. Disassemble the gear pump, appropriately increase the axial gap that is grinding the end face of the gear; with a surface grinder polished front and rear cover end face and the gear end face and remove gear on the burr (can not be chamfered); The depth of the unloading trough on the end face of the end cap will vary, and the width should be appropriately increased.