Although powder metallurgy sprockets are difficult to count separately in the entire powder metallurgy parts, the proportion of powder metallurgy sprockets in automobiles and motorcycles is much larger than that of powder metallurgy parts in other categories, regardless of weight or number of parts. . Therefore, from the increase in the proportion of automobiles and motorcycles in the entire powder metallurgy parts, it can be seen that the powder metallurgy sprockets are in a rapid development position in the entire powder metallurgy parts. If divided according to the characteristics of the parts, the sprocket is a structural part, and the weight of the structural part in the entire iron-based part is much larger than the other types, powder metallurgy parts. (1) Camshaft toothed belt wheel Camshaft toothed belt wheel is a powder metallurgical part commonly used in various automobile initiators. After one-time forming and finishing process, no other post-processing processes are required, and the dimensional accuracy requirements can be completely reached. , Especially the tooth profile accuracy. Therefore, compared with the traditional mechanical processing method, the material input and manufacturing are greatly reduced. It is a typical product that exhibits the characteristics of powder metallurgy. Examples of supporting powder metallurgy parts. Part names of supporting categories: automobile engine; camshaft, crankshaft timing pulley, water pump, oil pump pulley, driving and driven sprocket, driving and driven sprocket, cam, bearing cover, shaker Arms, bushes, thrust plates, valve guides, intake and exhaust valve seats, automobile gearboxes; various upper and lower speed synchronizer gear hubs and components, clutch sprockets, cams, camshafts, sliders, shift levers, shafts Sets, guide blocks, synchronization ring motorcycle parts: driven sprocket and components, sprocket, starting pawl, ratchet, star wheel, double sprocket, auxiliary sprocket, speed sprocket, push rod cam, bushing , Sliding bearings, centering sleeves, driven discs, intake and exhaust valve seats, automobile and motorcycle oil pumps: various oil pump sprockets, gear hubs, various oil pump rotors, cam rings, various pistons for automobile and motorcycle shock absorbers , Bottom valve seat, guide seat compression machine various pistons, cylinder blocks, cylinder heads, valve plates, seal rings, agricultural machinery products, various bushings, rotors, bearings, etc.: distributor sprocket, planetary sprocket, internal gear disc, combination The inner sprocket, various stainless steel nuts, and magnetic poles. Although the powder metallurgy industry has undergone high-speed development for nearly 10 years, there are still gaps in the following aspects with the same industry abroad: (1) There are many enterprises, small scope, and economic benefits. There is a big difference between foreign companies. (2) The products are interspersed, and the enterprises lower prices each other, and the competition is extremely fierce. (3) Most companies lack technical support, lag behind in research and development, and have low product levels, making it difficult to compete with foreign countries. (4) Lack of input and disturbance. (5) Z art equipment and supporting equipment are backward. (6) The export of products is small and the trade channels are not smooth. With my country’s accession to the WTO, the above-mentioned deficiencies and weaknesses will improve. This is due to the gradual internationalization of the market after China’s accession to the WTO, and the opportunity for further expansion of the powder metallurgy market; and at the same time with the entry of foreign capital and technology, powder metallurgy And the related technical level will surely be improved and developed. Metallurgical sprocket 1. The tooth profile of the sprocket The tooth profile of the sprocket must ensure that the chain enters and exits the mesh smoothly and freely, minimizes the impact and contact stress of the chain link during meshing, and is easy to process. The tooth profile of the commonly used sprocket is shown in Figure 1.It is composed of three arcs aa, ab, cd and a straight line bc, referred to as three arc-straight tooth profile.Standard tool for tooth profile For processing, there is no need to draw the tooth profile of the end face on the sprocket work drawing, just indicate "the tooth profile is manufactured according to the 3RGB1244-85 rule" on the drawing, but the shaft surface of the sprocket should be drawn For tooth profile, please refer to the relevant design manual for its dimensions. The parameter calculation was mentioned before, so do not repeat the narration! 2. Sprocket structure Figure 3 shows four commonly used sprocket structures. Small-diameter sprocket is generally made of integral type (Figure 4a), and medium-diameter sprocket is mostly made of spoke plate type, which is convenient for handling, clamping and Reduce weight, open holes in the web (Figure 3b), and the large-diameter sprocket can be made into a combined type (Figure 3d). At this time, the ring gear and the wheel core can be made of different materials! For example C45, no Materials such as stainless steel. 3. Sprocket information The sprocket material should ensure that the gear teeth have sufficient strength and wear resistance, so the sprocket tooth surface is generally heat treated to make it reach a certain hardness.