Calculation method to calculate the diameter of the gear teeth addendum circle diameter = (number of teeth +2) * modulus (normal tooth) pitch circle diameter = number of teeth * modulus root diameter = (number of teeth -2.5) * modulus (normal tooth) For example: M4, 32 tooth tip circle diameter = (32 +2) * 4 = 136mm pitch circle diameter = 32 * 4 = 128mm root diameter = (32-2.5) * 4 = 118mm This calculation method for all modulus gear (not including displacement gear). Modulus indicates the size of the gear teeth. Gear modulus = pitch circle diameter outer diameter gear teeth = ÷ ÷ (number of teeth +2) select gear gear modulus modulus national standard GB1357-78. Preferred modulus: 0.1mm, 0.12mm, 0.15mm, 0.2mm, 0.25mm, 0.3mm, 0.4mm, 0.5mm, 0.6mm, 0.8mm, 1mm, 1.25mm, 1.5mm, 2mm, 2.5mm, 3mm, 4mm, 5mm, 6mm, 8mm, 10mm, 12mm, 14mm, 16mm, 20mm, 25mm, 32mm, 40mm, 50mm; optional modulus: 1.75mm, 2.25mm, 2.75mm, 3.5mm, 4.5mm, 5.5mm, 7mm , 9mm, 14mm, 18mm, 22mm, 28mm, 36mm, 45mm; rarely used modulus: 3.25mm, 3.75mm, 6.5mm, 11mm, 30mm; regarding heat treatment, of course, all steel castings must be standardized in order to eliminate the internal pressure. Some parts of the gear can be welded castings. If welding castings foundry, welding position must be annealed. If hobbing high hardness, you can re-annealed to reduce the hardness and eliminates internal hard points. After processing and hobbing, gear or so-called quench hardening treatment to increase the surface hardness of the gear teeth. For small gear, you can do carburized. For large driven gear, you can do a surface hardening treatment. Some gear manufactured by the forging process. Internal gear forging better tissue density and higher strength. Forged gear may be used for more stringent working conditions. Strong low casting gear, but is widely used in the general working conditions. Gear forging high cost and relatively low cost of casting a gear. Buyer should select the appropriate manufacturing process based on the cost and conditions of use. Indexing method for finding 23 round d = mz pitch p = mπ tooth thickness s = mπ / 2 space width e = mπ / 2 base circle db = d * cosα = d * cos20 ° addendum ha = (ha *) * m headspace C = (c *) * m dedendum hf = ha + c = (ha * + c *) m addendum circle da = d +2 ha root circle df = d-2hf full tooth height h = ha + hf center distance a = (d1 + d2) / 2 = m / 2 (Z1 + Z2) in the form of a failure of the tooth surface wear or gear for open gear lubricants containing closed dirty due to tooth relative sliding between the surfaces, so that some hard abrasive particles into the friction surface, thus changing the profile of the teeth, increased backlash that excessive thinning causes the gear teeth off. Under normal circumstances, only the mixed grit abrasive wear will cause the tooth surface in the lubricant during operation. 2, glued to the tooth surface gear speed overloaded, because the friction between the tooth surface is large relative velocity large, resulting in the engagement zone temperature is too high, once the poor lubrication conditions, the oil film between the tooth surface will disappear, making two metal surfaces in direct contact with the teeth, thus bonded to each other occurs. When the relative movement continues two tooth surfaces, hard tooth surface portion of the material softer in the sliding direction of the tooth surface tear groove is formed. 3, the pitting fatigue rounds intermeshing teeth contact and reaction force between the tooth surfaces so that the two contact stress generated on the surface of the work, since the position of the engagement point is changed, and the gear is made periodic motion So contact stress is based on changes in the pulsation cycle. In this long tooth surface contact stress under the action of alternating, at the tooth surface at the marks appear small cracks over time, such cracks in the surface and gradually scale, the cyclic crack formation, the wheel produce tiny tooth surface area formed by some of the fatigue spalling shallow pit. 4, broken teeth bear the load of the running gear works as a cantilever, its roots by the periodic pulse stress exceeds the fatigue limit gear material, will produce cracks in the roots, and gradually expand, while the remaining part can not afford to drive broken teeth phenomenon occurs when the load. Gear as a result of serious shocks, partial load and uneven material may also cause broken teeth. 5, tooth plastically deform under impact loading or overloading, the tooth surface is easy to produce localized plastic deformation, so that the involute tooth profile of the surface deformation. Powder main gear (1) the camshaft sprocket camshaft sprocket various commonly used in automobile engine powder metallurgy parts, and by forming a finishing process, no other post-treatment process can be fully achieved dimensional accuracy, especially the accuracy of tooth. Therefore, as compared with the conventional machining method of manufacturing the material and manufacturing inputs are greatly reduced, which is a typical characteristic reflects metallurgy products. Examples of powder metallurgy parts supporting parts supporting category Name: car engines; camshaft, crankshaft timing pulley, water pump, oil pump pulley, active, driven gear, active, driven sprockets, cams, bearing caps, rocker, bushings, thrust plate, valve guides, intake and exhaust valve seat auto gearbox; variety of high and low speed synchronizer hub assembly, clutch gears, cams, camshafts, slider, shift lever, bushings, guide blocks, synchronizer ring motorcycle parts; driven gear and components, sprockets, starter pawl, ratchet, star wheel, double gear, pinion, gear, putting cams, bushings, bearings, centering , driven plate, intake and exhaust valve seats, automobile, motorcycle oil pump; various oil pump gears, gear hub, a variety of pump rotor, cam ring automobile, motorcycle shock absorber piston various bottom seat, guide seat compressors of various piston, cylinder, cylinder head, valve plate, sealing rings of various agricultural products bushings, rotors, bearings.