How to repair the excavator

First, the engine water temperature is high, after the thermostat is removed, the small hole below the thermostat seat is plugged with wood plug to prevent hot water recirculation.

Second, the gear pump separates the side to generate a vacuum as a suction port. The volume on the side of the extrusion becomes small, and pressure is generated as a discharge port. The back of the 3-shaped valve plate always faces the discharge port. The valve plate generates an axial force of the squeeze gear under the pressure of the pressure oil to strengthen the seal. There is also the effect of automatically compensating for the pressing force after wear.

Third, the smallest core in the pilot handle mainly plays the role of micro-operation.

Fourth, individual parts are often blocked, it should be checked whether the connected pipeline is caused by internal peeling. Excavator spare parts

5. The middle of the spring of the distributor stem is thinner than the outer ring, which should be the stroke buffer at the end of the stroke. The intermediate sleeve limits the stroke of the stem.

Sixth, the approximate judgment of the iron filings: 1, the shiny is the cylinder, because of the low speed, no loss of luster. 2, hair is a pump, or motor bearing is produced, because of high speed rotation, matt.

Seven, the second pilot pressure is normal, but the action is slow, the car loaded hammer, should consider whether the spool in the pilot handle has dirt to limit its stroke, so that the stroke is reduced (even if the operation is maximum), although the pressure is sufficient, but the flow is insufficient, resulting in The force is not enough on the valve stem, the valve stem is not open enough, and the related action will be slow.

Eight, joint action Some action is slow, or does not move. The associated pilot secondary pressure is below 20KG.

Reason: When replacing the handle oil seal, the small core on the lower side falls below, not in the hole of the valve stem. In the field, the wire with long and thick difference is replaced, and the test is OK.

Nine, K3V main pump proportional solenoid valve check valve installed reverse: the whole vehicle pressure will be low, the pilot pressure is quite high, and will also brake.

X. About walking weakness. For vehicles parked at the beach for a long time, the track shaft will rust and cause great walking resistance. Powerless. Action: Replace the track shaft.

Ten, the handle becomes heavier

1, the reason: the handle back to the oil pipe is not smooth

Treatment: Replace the return pipe

2, the reason: the relevant action of the handle pilot control spool is blocked by a small hole

3, after cleaning, OK

11. The second pilot pressure of Komatsu-6 is lower than the standard (28kg). It should be checked whether the contact between the pressure plate and the bullet of the handle is worn out and the pit is too small. Can be ground after welding

deal with.

12. Black smoke: oil head, oil pump, supercharger (including intercooling, pipeline), air filter, and then hydraulic pump overload.

Thirteen, the faster the pressure is established when the pump is doing the action, indicating that the pump state is better.

14. After the pump is installed, the kerosene can be leaked at the high pressure port. If it leaks, find the cause. Is the distribution plate installed, the pressing force is not enough, the cylinder and the disk, the disk and the intermediate are not well matched.

Fourteen, K3V plunger pump principle summary:

1, the skates on the skateboard not only the revolution, but also the rotation. The rotation is rotated with the cylinder, and the angle between the shoe and the skateboard changes, and the centripetal force is generated to make it rotate. If the plane difference of the shoe exceeds 0.01mm, it should be treated (using a 0.01mm feeler gauge on the plane)

2. When normal, the shoe forms a layer of oil film on the surface of the skateboard. Ideally, it is static pressure and does not touch. If the surface tolerance of the shoe exceeds the standard, the oil groove is deformed and blocked, and the oil film is destroyed, causing the shoe and the skateboard. Direct contact, the skates are quickly damaged.

3. Whether there is any scar or deformation in the oil tank of the sliding shoe. If it is necessary to repair, the oil tank must be unblocked.

4. The pressure inside the pump should not exceed 3KG. If it exceeds the pump, it will be damaged soon (the shoe is worn and worn).

5, many pumps have been repaired soon after they are damaged (before the pump broke), dismantling found excessive wear of the shoes, should analyze whether the pump pressure is too high, the resistance is too large, is the last pump hit After the failure, the oil return line of the pump was not cleaned, and the residue hindered the return of oil in the tube, causing the oil return pressure to be too high and the pump to be damaged quickly. (especially Carter pumps).

6. The return pipe of the general pump directly enters the oil inlet side of the fuel tank, and does not pass through the oil return filter to avoid poor oil return, which causes the oil return pressure in the pump to be too high.

7. Pumps, road rollers and other construction machinery use closed circuit, that is, the pump output and input are shared pipeline fuel tanks can be used, or small.

Fifteen, hydraulic oil temperature: the oil temperature in the fuel tank is not more than 90 degrees (old car), the new car is within 80 degrees.

16. When the hydraulic pump is being repaired, after the cylinder and the plunger are removed, it is best to make a mark. When reassembling, follow the order of removal, to avoid the bad friction of the even part, resulting in excessive internal leakage.

Seventeen, the main factors of high hydraulic oil temperature: 1, leakage; 2, throttling; 3, heat dissipation

18, the hydraulic fuel tank cap is damaged, can not maintain the pressure, there will be no back pressure in the fuel tank, the pump suction port has no pressure, the oil inlet resistance increases, the pump is easy to inhale air, causing premature pump damage.

Nineteen, K3V 112 regulator:

1, power adjustment spring - large 5 turns, 6.5 turns, small springs are generally 5 turns.

The holes in the center of the small pieces on both sides of the feedback rod assembly have large holes and small holes, so pay special attention. The springs of the two regulators must be the same size, and the holes of the plates must be the same. Otherwise, the variables will be out of sync, the brakes will be slow, or the pressure of the two pumps will be inconsistent.

2. Regarding the brakes, the change of the P----Q curve should be considered, that is, it is inconsistent with the factory setting of the original car, or the engine power is insufficient, causing the variable to lag, resulting in a brake phenomenon. The reason for this is to consider whether the gap between the parts is too large, such as the pin and hole of the feedback rod assembly, the pin and rod inlay, the servo piston ball head and the swash plate connecting the ball hole, etc. And become smaller. There is also the gap between the power control step valve plug and the sleeve, which is crucial. The gap between the 652 small servo valve stem and the sleeve, whether the shoulder size of the servo valve stem changes, and whether the transition groove on the rod is excessively worn will cause a delay in the variable and cause a brake. To analyze in detail.

3. The pump proportional solenoid valve acts as the closed-loop control pump's absorbed power and engine output flow. It can automatically compensate the engine, pump, and adjuster performance changes so that the P---Q curve is as close as possible to the factory design standard, and the engine power is utilized. Maximize the purpose. Therefore, the execution function of the proportional solenoid valve and the circuit control function of the front stage are very important. Generally, the speed sensing control, that is, the input and output control functions of the speed sensor and the computer board must be good, and the pilot pressure must be normal. Otherwise, the P-Q curve will also be biased to cause a brake.

4. If the pump is set to a minimum swing angle, it will brake during the overflow operation.

10, black smoke

The main pressure of the boom is generally 110-120Kg at no load. If the pressure is too high, the oil return resistance should be considered too large. Cause 1. The dispenser stem is incorrectly installed. 2. The oil back pressure is too high, check whether the oil return check valve is stuck, whether the oil return filter is blocked or not.

P---Q curve variable pressure is generally around 140Kg at no load. If you add proportional solenoid control, you can advance.

Second, about the car

1. If the engine is smoky when the load is heavy and the engine speed is severe, the hydraulic pump may absorb more power than the engine power. If the displacement is lowered a little, the vehicle phenomenon will be improved, which is a hydraulic problem. 2, the engine power is insufficient, check the oil circuit, air filter, boost pressure, fuel supply advance angle and so on.

Third, the point of suspected hydraulic leakage, the temperature should be higher than other points, can be measured by infrared scanner.

Fourth, the common rail engine cylinder is not working properly or does not work, the corresponding exhaust manifold can be poured with water, the temperature will be slightly lower than the normal operation.

Five, the handle is heavy: 1, the pilot pressure is low, the oil filter is blocked. 2. The handle returns to the oil pipe and the oil tank is not smooth, resulting in excessive oil return resistance.

Sixth, the engine silicone oil fan clutch slips to cause water temperature and high oil temperature treatment method: the silicone oil clutch is disassembled with an impact screwdriver, the silicone oil will flow out, and the appropriate thickness of the inner tube of the car is placed in the middle, after reinstalling, the hand is shaken if Can't move, it won't slip.

7. Disassembly of the motor brake piston: It can be topped out with a grease gun.

Eight, Hitachi pump often stuck three steps: the pump bearing is damaged, the iron filings enter the three steps, causing the stuck. At the same time, the distribution plate will also have severe strains, and the entire surface of the distribution plate will have deep tensile marks, which is also caused by damaged bearing iron filings.

The difference between A8V107 and A8VO107:

A8V107 pump means the plunger is single ring

A8VO107 means the plunger is double ring

If the ring is broken, the pump tube vibration is quite serious.

9. After changing the hydraulic oil, the whole car has no action.

Cause: The replaced oil reacted with the original oil, the 7 valve stems were dead, and the pilot lock solenoid valve was stuck.

Disposal: Disassemble the dispenser, solenoid valve, etc., thoroughly clean the valve stem, core, etc. with a toothbrush

30. When disassembling the pump and the motor gear, mark the meshing position between the gear and the gear and the internal gear of the gear before the removal, to ensure that the assembly is assembled according to the meshing mark to prevent new meshing noise. .

Thirty-one, small digging pump swashplate and the sliding surface of the sliding plate if it is not flat, you can go to the lathe, use the knife to mill to eat all, then use the pump to grind into a glossy surface, then use a thicker skateboard to install, otherwise, the plunger will bite side.

Thirty-two, Hitachi or Kobelco—8-slewing motor skeleton oil seals need to borrow a special tire when disassembling, and evenly press the oil seal down to damage the bearing.

Thirty-three, when the motor cover is assembled to the shell, the inlet port is generally the highest position to the plunger. https://jnjmzm.wixsite.com/sdjygcjx