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Plunger oil pump wear characteristics, identification and repair
First, the plunger wear characteristics, identification and repair 1. The wear characteristics of the plunger and the coupling wear of the plunger assembly are mainly concentrated on the plunger head, the lintel, the stopping edge, and the inlet and outlet holes of the plunger. (1) Wear Characteristics of the Plunger Head Here, the maximum wear occurs. There are groove marks on the contact surface that are shallow and deep, and coarse and fine, and the wear is milky white. This is particularly evident under light. The furrows have a maximum depth of 0.023-0.025 mm, a maximum width of 4-5 mm, and a length of about 10 mm. (2) Wear characteristics of the plunger head lintel The wear here is smaller than that of the plunger head, and it is mostly a comb-shaped, not deep, thin groove pattern. Similarly, it is shallower and deeper, and the thicker and the thinner. (3) Plunger The wear characteristics of the stop edge gradually decrease from the upper edge of the chute, and the wear width is about 5 mm, which is milky white, and the edge of the stop edge is dulled round.(4) Wear characteristics of the lower shoulder of the plunger Here the wear is very small, only short fine lines on the circumference of the shoulder (5) wear characteristics of the plunger sleeve wear is mainly in the vicinity of the oil return hole, and the oil inlet hole is larger than the oil return hole. The wear part is along the centerline of the hole. The upper wear extends upwards from the upper edge of the hole by about 6-7 mm, and the depth is about 0.024-0.027 mm. The lower part extends down from the lower edge of the hole by about 4.5 mm, and the depth is about 0.015- 0.017 mm, the wear width is larger than the diameter of the hole.The wear of the surface near the oil return hole is mainly on the left, about 2-2.5 mm wide, extending 2-3 mm upward, extending 4-5 mm downward, and the wear on the right side of the hole is very small. 2. Identification of Plunger Pairs For the identification of plunger couples, the first is to carry out a general inspection by visual inspection. Whether there are obvious defects or not, pass the test for further qualification for qualified or indefinable (1) visual inspection and identification with the naked eye to see the head of the plunger, around the stop edge or around the plunger sleeve oil hole, due to wear and tear Milky white, with a clear feeling with a nail scraping, plunger or sleeve rust, cracks, the top of the plunger or stopping the edge peeling, etc., with one of the above defects, the plunger is scrapped. The vacuum method is used to mark the top hole of the plunger with your right index finger. The left hand pulls the plunger out slowly. At this time, the index finger of the right hand should feel suction. When the plunger is about 2/5 full length, it will loose quickly. When the plunger is opened, the plunger rapidly returns to the original position under the action of vacuum suction, which means that the plunger can be used continuously, otherwise, it should be replaced with a new one or be repaired. Test, insert the plunger assembly into the injection pump body, insert the oil valve seat and other parts, do not install the oil valve and the outlet valve spring, tighten the tight seat of the oil valve, and tightly close the oil pump outlet valve The seat end is connected to the high pressure tubing connector of the injector tester so that the plunger is at the maximum fuel level Pressurize the hand pressure rod of the fuel injector tester so that the oil pressure rises to 22540 kPa, stop pumping oil, and measure the time required for the oil pressure to drop from 19,600 kPa to 9,800 kPa. The value should be in the range of 16-29 seconds. Otherwise, it is unqualified 3. Plunger fittings repair (1) The upper surface of the plunger sleeve can be coated with a grindstone with a particle size of 600 or more on the thick glass, and grind the upper end surface. The glass plate is kept vertical, light and even, while rotating, while moving, and constantly changing the direction of rotation, grinding to the end of the surface smooth without scratches.(2) plunger in the plunger sleeve is generally in the newly replaced column Commonly used in plugs, the oil can be coated on the plunger guide with the plunger sleeve.If the tightness is too large, the polishing paste should be applied to each other.When grinding, you can use the bench drill or hand drill to grip the plunger. Hold the plunger sleeve in the right hand and move it back and forth with each other. For the plunger that touches the top, use a fine oil stone with a particle size of 800, apply the oil, tilt the plunger 30 degrees or so, and gently turn the stopper to remove the burrs. (3) Replace the new parts with worn plunger parts. Second, the oil valve wear characteristics, identification and repair 1. Outlet valve wear characteristics of the wear and tear valve parts wear, mainly in the sealing cone, decompression ring and guide section. (1) Wear characteristics of the sealing taper Here, the abrasion is large, so that the width of the valve seat ring is increased and the smoothness is decreased; the ring groove is formed on the taper surface of the oil valve, and the depth is about 0.05 mm. (2) The wear characteristics of the decompression belts are also worn here. The decompression belts after wear are conical, and they are large and small. The surface of the cylinder is full of groove marks, and the depth is shallow and deep; The lower edge is rounded due to wear. (3) Wear characteristics of the guide surface Here, the wear is small, the upper part is larger than the lower part after wear, and the guide part matching the pressure relief ring of the oil discharge valve seat and the oil discharge valve seat also has wear. 2. Identification of Outlet Valve Couplings (1) The general appraisal is observed by the naked eye. If the delivery valve couple has one of the following defects, it cannot be used again. 1 Decompression rings with severe signs of wear, milky white scratches, noticeable scratches with nails, or axial nicks on the circumference of the decompression ring are so dense that the original surface finish is not visible. 2 too much wear on the sealing cone surface, the sealing ring is too wide or there is collapse on the sealing ring. 3 When the oil valve and valve seat have rust, or there is metal peeling and deep abrasive nicks. 4 When the lower plane of the oil valve seat is seriously rusted. 5 There is a noticeable ring groove mark on the sealing cone of the oil outlet valve seat. (2) Easily test the tightness of the outgoing valve's seal. Qualify the simple test of the seal cone. Hold the oil valve seat with the thumb and middle finger, press the oil valve with the index finger on the valve seat, and suck the oil out of the mouth. The hole in the plane under the valve seat is moved to the lips. If it can be sucked by the lips, the sealing performance is good. It is also possible to install the oil valve assembly into the oil pump body without the plunger. Check the compressed air of 294-490 kPa from the high pressure fuel pipe connection. If there is no air leakage, the sealing performance is good, otherwise new parts should be repaired or replaced. 2 Simple Sealing Performance Test of Pressure Relief Belts Identify the hole with the thumb against the lower plane of the oil valve seat, place the oil valve into the valve seat, and gently press down with the index finger to enter the valve seat when the pressure relief ring enters the seat. At that time, I felt that there was an upward rebound of compressed air. When the index finger is released, the oil valve can rebound and say. The tightness of the pressure relief ring and outlet valve seat is good, otherwise it is unqualified. For the new replacement valve, a sliding test is also required. Pull out the oil valve immersed in diesel, hold the valve seat, keep it in the vertical position, and then pull out the valve about 1/3 of the valve body, that is loosen the valve, the valve body should be able to The weight is dropped on the valve seat, and the oil valve is rotated at any angle. The result should be the same. 3. The critical part of the delivery valve assembly's repair to determine whether the oil valve can continue to work is the sealing cone. When there is slight abrasion or poor contact on the sealing cone surface, the sealing cone can be evenly coated with abrasive paste, and then inserted into the valve seat to be ground and ground. After several grindings, the grinding can be performed in one direction. Be careful not to stick the paste to the decompression belt. After grinding for a certain period of time, the abrasive slurry is washed off, the diesel fuel is ground, and the oil valve is tapped on the valve seat several times. Grind, clean, and then seal performance test.