The 195T diesel engine is the supporting power for the Taishan-12 tractor. Valve leakage is one of the common causes of power drop. This article describes the commonly used repair methods for the valve and valve seat of this diesel engine. 1. When the air leakage between the valve and the valve seat is not serious and the corrosion is slight, the defects can be eliminated by mutual study. First, apply a little rough grinding paste on the valve seat contact ring and apply a little lubricant to the valve stem. Insert the valve guide tube, and then use a wooden handle rubber bowl to suck the valve, constantly beat up and down and left and right rotation, and constantly change the valve and valve seat contact with each other. After removing the defects, fine grinding is used to study each other. After the mutual study, it should be a seal ring with a width of 1-2mm in the middle of the slope and no luster. After the mutual study is completed, it should first be cleaned, thoroughly remove the grinding paste and metal chips, and then perform the sealing inspection. There are many methods of sealing inspection. Generally, after the valve mechanism is installed, kerosene or diesel oil is injected into the intake and exhaust passages of the cylinder head. After the 3-5 minutes of gas entrance, there is no oil leakage phenomenon, and the sealability is considered to meet the requirements. 2. The reaming valve seat relies on the valve seat in two cases. One is when the valve seat contact ring is heavily corroded, and the other is because the valve recession exceeds the limit of use and the gas seat is replaced. After the circle. Before the hinged seat, a suitable set of reamers and arbors should be selected according to the valve size. Valve reamers of various sizes have three kinds of bevel angles, ie, 75 degrees, 45 degrees, and 15 degrees, and 45 degree reamers are divided into two straight (fine hinges) and toothed (rough hinges). Reamers facilitate machining hard surfaces. The order of the ream seats shall be: 45 degrees for coarse hinges; 15 degrees for hinges, narrowing the width of the valve seat contact band from above; 75 degrees hinge angle, reducing the width of the valve contact band from the lower position; 45-degree angle for the precision hinge. The reaming of the 75 degree and 15 degree slopes determines the position of the valve seat and the valve contact annulus. Therefore, when the reaming is performed, the valve technique should be continuously used to check that the contact annulus is approximately in the middle of the inclined plane of the valve head. If the contact ring is on the upper side, a 75-degree reamer is used to add the 15-degree bevel reaming amount; if the contact ring is lower, a 15-degree reamer is used to increase the reaming amount of the lower-hole 75-degree bevel. Here, by the way, some of the introductions stated: "With a 15 degree reamer and a hinged amount of 15 degrees on the upper mouth, a 75 degree reamer is used to increase the sales of the hinge on the lower end of the 75 degree slope." The definition of the knife angle is wrong. The angle of the reamer is the angle between the working surface of the blade and the center axis of the reamer. The angle of the valve seat sloping surface is the angle between the horizontal reference surface of the cylinder head, so it should be A 15 degree reamer reams the valve seat with a 75 degree bevel. This point, in practice, although not mistaken (because it will feel what kind of reamer should be used to see a try), but when the situation is written into text material is still more rigorous. The reaming of the 75 degree and 15 degree inclines also determines the width of the contact zone between the valve seat and the valve. The contact ring should not be too wide to facilitate sealing; nor should it be too narrow to avoid excessive wear. In general, the width of the seal ring should be 1-2mm after the mutual development (after the valve seat is reamed, it needs to be studied with the valve). When reaming the valve seat, the gap between the reaming rod and the valve guide tube must not be greater than 0.05 mm, otherwise the valve seat may be easily deflected. After the valve seat is reamed, the valve should be installed to measure the depth of valve sag. The amount of sagging of the intake and exhaust valves of the 195T diesel engine is specified as 1.0-1.8mm and the limit value is 2.5mm. When the amount of valve retraction is too large, it should be circled and repaired. 3. Valve seat re-inserted The inlet and exhaust valves of the 195T diesel engine are originally fitted with a seat ring. When the amount of gas sinking is too large or the original seat ring is loose, the old ring can be removed, and the new ring is re-inserted. It can be made of the same material as the cylinder head. The hot gas inserting method can be adopted when inserting the new gas six-seat ring, and the cold inserting method can also be adopted. (1) Heat setting. The outer ring surface of the seat ring should be polished, the surface roughness parameter value Ra is not more than 0.80um, the cylindricity error is not more than 0.01mm, and one end of the outer cylindrical surface should be machined with a chamfer angle of 0.545 degrees. The hole at the cylinder head insert valve seat should also be machined for boring, the cylindricity error of the boring hole should be no more than 0.01mm, and there should be 0.20-0.30mm interference between the outer cylindrical surface of the seat ring and the boring hole. The cylinder head should be heated to 400-425 degrees Celsius before the seat is pressed in. After the seat ring is pressed in, the end face of the seat ring should be cut to a certain depth to ensure the required amount of sinking after valve assembly. Then, the valve seat is hinged and the valve is researched and checked for sealing performance. (2) cold setting. Except for the requirement of 0.15-0.20mm of interference and no heating, the rest is set with heat. 4. Grinding Valve If the valve head slope erosion is serious, if it does not replace the new one, it can be ground on the valve grinding machine, and the angle should be adjusted before grinding. After grinding, the height of the cylindrical portion of the valve head shall not be less than 105mm, and the radial circular runout of any point on the inclined surface shall not be greater than 0.05mm.
2 Wire Intercom System,2 Wire Intercom,2 Wire Video Intercom,2 Wire Door Entry System
Zhuhai Mingke Electronics Technology Co., Ltd , https://www.mingke-tech.com