Combined camshaft for engine

Abstract

The combined camshaft of the engine, the combined camshaft has a segmented structure and is composed of at least two shaft section units. positioning slot, and has a central hole. The combined camshaft is assembled by all the shaft unit units sequentially connected back and forth. Locating pins and positioning slots are used to locate the phase of the cams on each shaft section, and all shaft section units are fixed by bolts passing through the center hole. The advantage of the present invention is that due to the self-centering effect of the taper surface fit, the coaxiality of each shaft section unit after assembly can be ensured, the segmented structure makes processing more convenient, and all shaft section units have certain versatility, which is convenient to adopt special Equipment and tooling are processed in large quantities to reduce costs, and the assembly of the camshaft does not require special equipment and tools, and each shaft segment unit can be replaced independently, which is convenient for use and maintenance.

Description

technical field [0001] The invention relates to a combined camshaft of an engine and belongs to the technical field of engines. Background technique [0002] The camshaft is one of the important parts of the engine. Its main function is to open and close the valve according to the designed time. The camshaft is mainly composed of the shaft diameter part and the intake and exhaust cam parts. At present, the camshaft of the engine is mostly an integral structure , that is, all the shaft diameters of the camshaft and the intake and exhaust cam parts are processed by one shaft segment. For a multi-cylinder engine, the integral camshaft is longer in length, the processing procedure is complicated, and deformation is easy to occur during processing, which affects the accuracy of the parts. Manufacturing The cost is high and the weight is also relatively large. With the development of engine technology, more and more combined camshafts are used. The current combined camshaft is us...

AI Technical Summary

Problems solved by technology

The installation and fixing method of the cam unit and the shaft diameter unit on the mandrel is the key to determining the quality of the combined camshaft parts. Among the installation and fixing methods currently used, some use the cam and the shaft diameter unit to press fit through interference fit. Fixed on the mandrel, some use the cam and the shaft diameter unit to heat and expand and then install it on the mandrel, and then fix the cam and the shaft diameter unit on the mandrel after cooling and shrinking, and some use the inner hole of the mandrel to add The pressure makes the mandrel expand, and then fixes it with the cam and the shaft diameter unit. Since the camshaft has high requirements on the angular position of the cam unit, the base circle of each cam, and the runout tolerance of the shaft diameter, the installation of the above-mentioned combined camshaft is fixed. The method has high requirements on the assembly process and tooling equipment, and special equipment is required for assembly. Sometimes after assembly, finishing is required to ensure the accuracy of the parts, which increases the cost and cannot be assembled repeatedly. If a certain cam or shaft is used If the radial unit is damaged, the camshaft needs to be replaced as a whole, which is inconvenient for maintenance and poor in remanufacturability

[0003] Chinese patent application 201710213304.X discloses a segmented camshaft, which divides the camshaft into several sections, and each section is connected to the front section with a connecting flange, which is positioned and fastened by positioning pins and bolts. There is a matching gap between the positioning pin and the pin hole, which will cause the runout deviation of the shaft diameter and the cam of the front section and the rear section, and the positioning accuracy is low, which affects the accuracy of the parts, and because the connecting flange is set on the shaft section, the diameter of the camshaft increases. , the engine needs to have enough layout space, usually only suitable for large engines, poor applicability

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