Tell you little knowledge of sprockets
In many construction machinery accessories, the chain is the most simple structure, many people have such a view, if you have always been so think, that Xiaobian really want to say to you and say.
Sprocket design: for pitch 12.7-38.1 standard chain sprocket, manufacturers have adopted standard hob on the gear hobbing machine. When processing, according to the user provides sprocket tooth number, pitch and roller diameter, manufacturers can produce. The sprocket is designed according to GBl244-85. Non standard sprocket on the basis of the user to provide the necessary data, to do the following calculation: pitch diameter: D degrees =P/sin180 degrees /Z=P, K, P- pitch, K- tooth number coefficient table.
The radius of tooth groove arc: the position of Rm surface arc radius is Do on the circumference of D 0.2P. Tooth groove separation quantity S: machine plus, Smin=0.08d; non additive, Smin=O.04P. Generally, the separation amount of the machine and gear groove is selected. Pitch angle a=360/Z. Tooth thickness: single row is 0.95 inside width of inner segment, double row is 0.93 inside width of inner segment. The addendum circle can be determined by drawing, and 0.85 or 0.95 times of the roller diameter can be added on the basis of the dividing circle. The above data is an important parameter for sprocket design.
Gear machining is the most important processing of sprocket tooth profile. As mentioned earlier, the standard chain sprockets are mostly machined on hob machines with hobs. The processing methods of large and non-standard sprockets are different due to the restrictions of equipment, cutting tools and quantity. At present, the most widely used method is still formed milling sprocket and hob hobbing sprocket two kinds.
The tooth shape of the roller chain sprocket cutter is designed according to the sprocket tooth shape. In order to save the cutter, the cutter is usually designed according to the number of sprocket teeth. Each group is designed according to the number of teeth calculated, and the number of teeth can be calculated by pressing formula: Zc=2Zl, Z2/Zl+Z2: Zl, the minimum number of teeth in the same group, the maximum number of teeth in the Z2 group.
1, shaping cutter machining method: using the shaping disc cutter or finger shaped milling cutter, in the horizontal or vertical milling machine with indexing head processing is the commonly used machining method. Suitable for batch processing of large pitch chain wheel.
2, saddle milling cutter tooth shape method: saddle milling cutter in the milling machine with dividing head at the same time on the adjacent two alveolar milling two symmetrical teeth, is the current tooth sprocket commonly used processing method. It is suitable for medium and small batch production.
3, hobbing machining tooth shape method: hobbing machine with hob machining slot, suitable for standard sprocket pitch less than P=38.1 sprocket processing. High production efficiency. Good accuracy.
4. Gear shaping method: on the gear shaper machine, the sprocket tooth groove is processed with a disc shaper cutter or a comb cutter. Suitable for single piece and small batch production.
5, larger sprocket can also take lineation, drilling, gouging or slotting machining tooth form is a processing method, it is obvious that this method is relatively backward, but large sprocket by processing equipment and quantity restrictions can also use this method.
6, recently, some units using profiling machine cutting tooth shape method to solve the problem of large sprocket machining, very creative.
