附 录F series of mini-car crankshaft machining process Crankshaft is a piston engine, one of the main parts and components, used to the reciprocating piston movement into rotary movement. According to the number of engine cylinders, crankshaft general sub-cylinder, double, triplex, four-cylinder and six-cylinder crankshaft. Such as the four-cylinder engine crankshaft has five main journal neck and four-link, connecting rod journal 180 in each angle into a plane. Crankshaft complex process, especially the micro-car crankshaft. Micro car Crankshaft journal size and high geometric tolerance requirements, generally based on six precision manufacturing, journal roughness to achieve Ra0. 2m. Some neck needed to be strengthened to deal with the surface to improve its wear resistance and fatigue strength. F series of mini-car crankshaft Most of the materials currently used high-quality alloy structural steel. However, due to a good cutting performance of ductile iron crankshaft, will be the preferred structural shapes, and steel crankshaft and can conduct various kinds of heat treatment and surface hardening crank handle to raise the anti-fatigue strength, hardness and wear resistance. Low-cost ductile iron crankshaft, at home and abroad has been widely applied. F series of mini-car to the ductile iron crankshaft crankshaft trend. The main author of steel micro-engine F-Series truck crankshaft machining process analysis1 Process Analysis 1.1 Crankshaft features and technical measures 1. 1.1 stiffness difference F Series crankshaft larger aspect ratio (usually L / d = 7-10), therefore less rigidity. In order to prevent deformation during processing should take the following measures: selection of a higher stiffness of machine tools, cutting tools and fixtures, etc., thereby reducing the deformation and vibration; to reduce the torsional deformation, bending deformation; in the process as far as possible the role of cutting force offset ; reasonable arrangements for work place in order to reduce the processing order of the deformation; additional alignment process. 1. 1.2 the shape of complex Connecting rod journal and the neck is not with a spindle axis, in the process of connecting rod journal imbalance easily be equipped to quickly find journal center is eccentric connecting rod fixture, and should be balanced block. 1. 1. 3 Technical requirements Micro-cars of the technical requirements of the crankshaft is very high, and its machining process with the production of different programs and the complexity of the crankshaft and a lot of difference, but generally include the following main stages: positioning the base of the processing; rough, Finish the spindle neck, and other cylindrical connecting rod journal; coarse grinding of the spindle neck, cylindrical connecting rod journal; large and small head screw and keyway processing; drill hole processing; semi-grinding spindle neck, refined grinding rod journal; journal surface treatment; Balancing; Superfinishing such as the journal. 1.2 Positioning the baseline choice 1.2.1 the choice of benchmark crude In order to ensure the center spindle hole drilled in the rough outer surface of neck position on the axis, the spindle neck chosen for the rough surface of the cylindrical base. At the same time in order to ensure that the processing of the axial size of the base-level, choosing the first on both sides of the spindle neck axial fan board for the benchmark crude. 1.2.2-assisted selection based on rough Fan on the board in a milling process that is processing plane used by the connecting rod journal supporting the benchmark crude. 1.2.3 the choice of the base fine Processing and its neck with the spindle axis of the outer surface of the journal, the central hole in the base for the fine. Connecting rod journal processing when processing the pin hole and a connecting rod journal cylindrical surface as a precision-based benchmarks, making it easier to ensure Technical requirements. In addition, the benchmark third-axial positioning of the two spindle neck surface level consistent with the Design Basis. 1.3 Crankshaft process At present the majority of F series of mini-car crankshaft, materials for 40Cr, rough pieces of steel for quenching and tempering. Process outlined as follows: 01.play central hole 02.car spaces folder 03.fine journal owners 04. Milling positioning 05.connecting rod journal Cart 06.the size of the first coarse grinding 07.car Gordonia ping, and other end- 08.ping head-end cars and other 09.coarse grinding spindle neck 10.connecting rod journal coarse grinding 11.hinge pin hole drilling 12.keyway milling 13.drill attack Flywheel screw 14.drill hole inclined 15.half-grinding spindle neck 16.connecting rod journal grinding 17.Balancing and to re- 18.grinding spindle neck 19.test 20.nitride 21.repair center holes, chamfers 22.grinding head 23.Finish bearing