Sprocket is an important part of chain transmission, sprocket tooth profile, pitch and other related to the chain size is correct, will be directly related to the life of the chain. Therefore, we must pay enough attention to. The shape and structure of the common chain wheel are usually, and the sprocket wheel is composed of three parts, a gear ring, a wheel and a wheel. Common shape: 1 sprocket monolithic single row chain wheel. 2 single flange type single row chain wheel. 3. Double flange type single row chain wheel. The structure of the chain wheel is approximately: 1 integral structure. Generally used in single and double row standard chain below P=38.1, single and double flange machining sprocket. 2 welding structure. Mainly used in the processing of large size, single and double flange sprocket. When processing the flange portion by rod skip into convex shape. The ring gear part can be used after the plate cutting process diameter and hole, hole end car welding groove set into the flange part of welding. Welding to both ends of the welding, the use of low hydrogen electrodes such as T506 welding rods, etc.. 3 Casting chain wheel. The processing is mainly used in the large sprocket, only when the processing processing gear ring, two flange end surface, outer diameter and inner diameter and keyway, then processing the tooth. Ring chain wheels are cast. Cast chain wheel material generally has two kinds, cast iron and cast steel, such as HTl5O, HT2O0 and ZG310-570 (ZG45). 4 forging chain wheel. Mainly used in the production of large medium and large size chain wheel. Forging, whether single or double flange flange type, usually forged into a convex shaft hole, set aside sufficient allowance, the material utilization rate is low, the cost is high. Two, the selection of the sprocket material does not require heat treatment of the chip chain wheel, can be used Q235, Q345 (16Mn), or 10, 20 steel manufacturing. The general hardness below HBl40, suitable for medium and medium chain wheel machining power, large. The chain wheel which is required to heat treatment is generally made of 45 steel, 45 steel forging, 45 cast steel or 4OCr steel, and is suitable for the processing of the main and driven chain wheel which is matched with the high strength chain. Cast iron chain wheel is mainly used in the low precision or complex shape of the sprocket wheel, such as ring sprocket, etc.. Three, the basic parameters of L Z-, the sprocket tooth number, 2 P-, 3 d-, chain pitch, roller diameter, 4 D, a pitch diameter, tip diameter of 5, 6, d d top, a root diameter, 7, 8, a pitch angle Q pressure angle, R a tooth groove radius. The first three parameters for the user to provide important data, after the order parameter for sprocket design parameters can be calculated with reference to the relevant standards. Geometry and design principles of the 1 sprocket teeth four, sprocket tooth shaped geometry: straight tooth shaped and straight tooth sprocket geometry has three common arc has been linear, linear, circular arc two has two convex tooth shape, a circular shape, the center has slot offset. 2 design principles: the design of sprocket teeth profile should meet the requirements of three aspects: meshing requirements, the use of requirements, the process and accuracy requirements. (1) ensure that the chain can smooth the meshing in and out, no interference phenomenon. (2) having sufficient capacity to accommodate the extension of the chain segment. (3) with a reasonable angle of action. (4) the tooth profile curve and the chain transmission condition. (5) to prevent the chain meshing and beating off the chain. (6) good processing technology. At present, the chain wheel standard which our country executes is GBl244-85 tooth shape. Five, sprocket design and processing 1, sprocket design: for the pitch 12.7-38.1 standard chain sprocket each manufacturer has adopted the standard hob in gear machine production. Processing, the user only need to provide a number of sprocket teeth, pitch and roller diameter can be produced. Sprocket design according to GBl244-85 design. Non standard sprockets provide basic necessary data on the user, do the following calculation: dividing circle diameter: D =P/sin180 /Z=P K, P- pitch, K- coefficient table of number of teeth. Tooth groove radius: Rmin=O.505d, d= roller diameter. Pressure angle -90/2 degree Qmax=140; Qmin=l20 degree -90/2. General selection of Qmax. Remax=O.12 (Z; Z+180); Remin=O.008d (; Z); the radius of the tooth surface; (; Z+2). General selection of Remax. The position of the arc radius of the tooth surface is d on the 0.2P circle of Do. Tooth groove separation S: machine plus, Smin=0.08d; non additive, Smin=O.04P. General selection machine plus tooth groove separation. Pitch angle a=360/Z. Tooth thickness: single row as in section 0.95 of the width of the row, as in section 0.93 of the width of the. The addendum circle can be determined according to the drawing, and can also be added with 0.95 times of roller diameter on the basis of dividing circle. The above data is an important parameter of sprocket design. Of course。 Special chain sprocket design and this is different, according to the relevant manual sprocket formula. 2, the sprocket tooth shape processing Sprocket machining is the most important is the tooth shape processing. In front of has been said, the chain of the chain of the chain wheel on the majority of gear hob processing. And the large size and non-standard sprocket processing methods due to the equipment and tools, the number of restrictions on the company's processing methods are different. At present, the most widely used is still the forming method of milling cutter wheel and fan roller cutting sprocket two. Tooth roller chain sprocket cutter is designed according to the shape of the sprocket tooth. In order to save tools, usually according to the number of sprocket teeth grouping design tool, each group according to the calculated number of teeth tooth design, calculation of the number of teeth can be calculated by the formula: Zc=2Zl Z2/Zl+Z2 type: Zl group with the minimum tooth number, together with Z2, was the largest number of teeth. (1) forming cutter tooth forming method: disc cutter or finger milling cutter, with dividing head horizontal or vertical milling machine processing slot is currently used processing methods. Suitable for large pitch chain batch