First, the wear characteristics of the plunger coupling, identification and repair 1, the wear characteristics of the plunger, even the wear of the plunger coupling, the main focus on the plunger head, the beam at the stop for the edge and the plunger into Back to the hole at.
(1) wear characteristics of the plunger head Here wear the largest in the contact surface with a shallow upper and lower, coarse rough under the small groove marks wear milky white, especially in the light of the obvious. The maximum depth of groove marks up to 0.023-0.025 mm, the maximum width of 4-5 mm, a length of about 10 mm.
(2 plunger head wear characteristics of the beam here than the piston head wear small, mostly comb-shaped deep furrows, the same on the deep under the light, rough under the fine.
(3) wear characteristics of the plunger stop edge from the upper edge of the chute upward wear gradually reduced, the wear width of about 5 mm, was milky white, while stopping the edge of the edge is blunt blunt round.
(4) wear characteristics of the lower plunger shoulder wear here is very small, only short lines on the shoulder circumference.
(5) wear characteristics of the plunger sleeve wear mainly in the back near the oil hole, and into the oil hole at the back than the oil hole. The wear area of the oil inlet hole is located near the centerline of the hole, and the upper wear extends about 6-7 mm upward from the upper edge of the hole, about 0.024-0.027 mm deep, and the lower portion extends downward about 4.5 mm deep from the lower edge of the hole, About 0.015-0.017 mm, the wear width is larger than the hole diameter.
The wear on the surface near the oil return hole is mainly on the left, 2-2.5 mm wide, 2-3 mm upward, 4-5 mm downward, with minimal wear on the right side of the hole.
2, the identification of the plunger coupling For the identification of the plunger coupling, the first is to use visual inspection to see if there are obvious defects, qualified or can not be determined, and then further identified by the test.
(1) visual identification with the naked eye to see the head of the plunger, stop around the edge of the hole around the plunger sleeve, due to wear and milky white, scratch with a clear sense of nails, plunger or set rust, cracks, columns Plug the top or stop for the edge of a flake, etc., one of the above defects, the plunger is scrapped.
(2) with a simple vacuum identification with the right index finger to cover the top of the plunger hole, the left hand slowly pull the plunger outward, then the right index finger should feel suction, when pulled about the plunger length of 2/5 When the plunger is released, the plunger quickly returns to its original position under the action of vacuum suction. This means the plunger can be used continuously. Otherwise, should be new or pending repair.
(3) sealing test identification injector test can be used to test the plunger into the fuel injection pump body, into the oil valve seat and other parts, not installed out of the valve and valve spring, tighten the oil Valve seat, the fuel pump outlet valve seat tight end connected to the injector tester high-pressure hose connector, the plunger at the maximum supply position, pressure injector tester hand lever, the hydraulic pressure Rising to 22,540 kPa, pump oil was stopped and the time required to reduce the oil pressure from 19,600 kPa to 9,800 kPa was determined. Its value should be 16-29 seconds. Otherwise, it is unqualified.
3, the piston coupling repair
(1) uneven upper end of the plunger sleeve can be used above the abrasive particle size 600 coated thick glass, grinding the upper end. Grind the plunger sleeve and the glass plate should be kept perpendicular, with light and uniform, while rotating, while moving, and continue to change the direction of rotation, grinding smooth end without scoring.
(2) Block in the plunger sleeve Blocking is generally common in the newly replaced plunger pair, the guide portion of the plunger can be coated with oil and plunger sleeve for mutual research. If the tightness is too large, it should be coated with polishing research. Grinding can be used to drill or hand drill to hold the plunger, hold the plunger sleeve with the right hand to move back and forth. For the top of the plunger touching the pin, you can use a fine size of 800 stone, coated with oil, the plunger tilted about 30 degrees, gently turning the plug to remove burrs.
(3) For severe wear of the plunger coupling, should be replaced with new parts.
Second, the valve wear characteristics of oil, identification and repair
1, the wear characteristics of the oil valve coupling parts The wear of the valve coupling parts, mainly in the sealing cone, vacuum ring and guide part.
(1) wear characteristics of the sealing cone wear larger here, the seat ring seal ring width increases, the finish decreased; in the valve cone there is a ring groove, the depth of about 0.05 mm.
(2) wear characteristics of decompression zone wear here is also larger, the decompression ring after wear tapered, up and down small; all over the surface of the cylindrical groove marks, the shallow depth; The lower edge is rounded due to wear.
(3) wear characteristics of the guide surface where wear less wear after the upper part of the lower part of the larger, in the oil valve seat and the valve seat decompression ring with the guide part also wear.
2, the identification of the valve valve
(1) General appraisal With the naked eye observation, if the valve has one of the following defects, it can not be used.
① Decompression ring with serious signs of wear, was milky white scratches, scratches with a clear sense of nails or decompression ring with the axial notch on the circumference of the intensive to see the original surface finish.
② seal conical surface wear too much, seal ring is too wide or in the seal ring with a collapse.
③ out of the valve and valve seat rust, or metal peeling and deep abrasive scotch.
④ out of the valve seat under the plane when a serious rust.
⑤ oil valve seat sealing conical surface has obvious groove marks, scratch with a nail feeling.
(2) out of the oil valve seal simple test identification
① seal cone simple test identification with the thumb and middle finger holding the oil valve seat, the oil valve with the index finger on the valve seat, with the mouth out of the hole under the oil valve seat, and moved to the lips, if Can be sucked lips, indicating good sealing performance. You can also put the valve assembly into the pump body, without a plunger, from the high-pressure tubing joints through the 294-490 kPa compressed air inspection. If not leak, indicating good sealing performance, or repair or replacement of new parts.
② decompression ring with a simple seal performance test identified with a thumb against the hole under the valve seat, the valve will be placed in the valve seat, gently press down with the index finger, when the pressure zone into the seat ring When, feel the upward rebound of compressed air. When you release the index finger, the valve can bounce up, then said. Ming vacuum ring and the valve seat hole of a good seal, otherwise it is unqualified.
For newly replaced oil valve parts, but also for sliding test. Will be soaked in diesel oil out of the valve coupling parts removed, hold the valve seat to keep it in the vertical position, and then the valve out of about 1/3 of the valve body, that let go, the valve body should be able to The weight of the role of the valve seat, and then turn the valve any angle test, the results should be the same.
3, the valve repair parts out of the oil valve determines whether the key part of the work is to seal the cone. Sealing cones a slight wear or poor contact, the sealing cone can be evenly coated with abrasive paste, and then insert the seat rotary grinding, grinding several times, and then converted one direction of grinding. Be careful not to stick the abrasive paste to the pressure relief ring. After grinding for a certain period of time, wash off the abrasive paste, and then dipped in diesel interoperability, and the valve in the valve tap a few times. Grind, clean, and then seal performance test.
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