Chapter 1: Overview of Sprocket Wheel and Process Flow
1.1 Overview of Sprocket Wheel
The sprocket wheel is widely used in industry, agriculture, military, medical and health care, science and technology, etc., and it is an intermediate link in various fields. The role of the sprocket wheel in life determines that his processing and design must also reach the most rationalization.
Sprocket transmission has its unique side, it is characterized by: a wide range of shaft spacing, transmission ratio of a certain, strong vibration-absorbing capacity, a certain degree of adaptability to harsh environments, work reliably act on the shaft of the force is small. Disadvantages are: the operation of the instantaneous speed is not uniform, high speed is not as smooth as the belt drive (toothed chain is better); chain work, especially due to wear and tear after the elongation, easy to cause *** vibration, and thus the need to add tensioning and vibration damping devices.
Because of the demand for the number and type of more, sprocket structure form is naturally more. When the size is small, can be made into one with the shaft; when the size is large, can be made into a connected structure, tensioning sprocket and roller structure.
1.2 Chain Wheel Processing Procedures
The machining process of the formulated parts is described according to a certain format and requirements, such as using the production plan to indicate, as a directive and tracking documents, that is, machining process regulations. Including: machining process card - for the description of parts machining process documents; process card - a detailed description of each process, can be used to directly guide the operation of the workers; inspection process card - for batch or large number of production in the important inspection process for a detailed description of the documents to guide the inspection.
The format of the chain wheel processing process regulations, different types of production requirements for the process regulations are different.
Chapter 2: Material and Heat Treatment of Sprocket Wheel
2.1 Material of Sprocket Wheel
There are many varieties of material of sprocket wheel, such as metal carbon steel, alloy steel, copper, plastic wood, cast iron and so on. Our factory produces sprocket wheel mostly choose the following materials:
(1) C45, C35 carburizing, quenching, tempering. The hardness of the teeth is 50-60HRC, used in Z≦25 sprocket with impact load.
(2) C45, 45Mn quenched and tempered. Tooth high-frequency quenching 40-50HRC, without severe shock, vibration requirements. Applied to wear-resistant sprocket. 40CrMo, teeth quenched 40-50HRC important sprocket requiring high strength and wear resistance. Q275 welded annealed ≈ 140HB, applied to low and medium speed, transfer power is not large, large size of the sprocket. Clip cloth tape, P <6KW, applied to higher speeds, the requirements of smooth transmission, low noise sprocket.
2.2 Heat Treatment
Precautions when quenching the sprocket: Usually the product quenching (tooth part of the high-frequency) is able to meet the requirements of the product process; however, the product bore or keyway from the quenching part of the product is very close to the high-frequency quenching or quenching of the whole will cause the product bore or keyway to become larger, as shown in Figure 1. Especially carbon steel products change more. Must be all screw holes or through holes on the product is well processed, and then quenched; otherwise after quenching drilling, tapping will be due to the high hardness of the product, and can not be processed. It will also increase tool breakage losses. When machining, the bore will be left with a margin, according to experience, the margin should be about 2mm. After quenching will be the lathe three-jaw chuck card products, lathe boring, car finished product for a circle, and then the product will be re-clamped car sprocket outer circle, and then boring the product to Figure 1 ￠ size, to meet the requirements of the drawings.