Composite Camshaft Finish Machining with Chip Shielding
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Solution Overview
Problem
Existing methods for producing built-up shafts, such as cam shafts with rotatable cams, face challenges in achieving precise functional surface alignment and dimensions due to expansion during assembly, leading to inaccuracies and costly subsequent machining.
Innovation Solution
The method involves chip-removing machining of non-rotatably connected components after complete assembly, with shielding to prevent chips from entering the intermediate space between rotatable and non-rotatable components, using disc-like shielding elements or encapsulation, and a fluid flow to ensure chip exclusion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If components are finished and ground before assembly, then manufacturing cost and time are reduced, but precision requirements are not fulfilled after assembly due to expansion and deformation
Solution Approach 1:
The patent applies preliminary action by performing chip-removing machining of the shaft body before assembling the components. This preliminary machining removes material from the shaft body to create precise mounting surfaces and positioning features, ensuring that when components are assembled, their functional surfaces will align correctly. The preliminary action of machining the shaft body establishes the geometric foundation that guarantees precision after assembly, resolving the contradiction between early finishing and post-assembly precision.
2Manufacturing precision
If chip-removing machining is performed after complete assembly, then precision requirements are fulfilled, but chips may enter intermediate spaces and impair rotatable components
Solution Approach 1:
The patent applies segmentation by dividing the shaft into distinct regions: the shaft body requiring chip-removing machining and the intermediate spaces containing rotatable components. By segmenting the machining operation to apply only to the shaft body and not the assembled components, the process achieves high precision on functional surfaces while preventing chips from contaminating the intermediate spaces. This spatial segmentation resolves the contradiction between achieving precision through post-assembly machining and preventing chip contamination.
Solution Approach 2:
The patent uses an intermediary approach by applying chip-removing machining selectively to the shaft body rather than to all components simultaneously. The machining process is mediated through the shaft body structure, which serves as the workpiece, while the rotatable components remain protected as separate entities. This intermediary application of machining forces chips to be generated only from the shaft body material, preventing contamination of intermediate spaces while still achieving the required precision on functional surfaces.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach ensures precise finishing of functional surfaces without impairing the rotatable components, maintaining precision and reducing costs by avoiding complex pre-assembly machining and chip-related damage.
Implementation Method 1
a fluid flow to ensure chip exclusion
Data Source
AI summary
The invention relates to a method of producing a composite shaft comprising a shaft body (1), at least one first component (2, 9) connected to the shaft body (1) in a rotationally fixed manner, and at least one second component (3, 8) rotatable relative to the shaft body (1), in which method the at least one first component (2, 9) and the at least one second component (3, 8) are pushed onto the shaft body and assembled in the intended sequence. In order to be able to produce such shafts in a simpler and more cost-effective manner and in order to be able to finish-machine the components connected to the shaft body (1) in a rotationally fixed manner only after the complete assembly of the composite shaft, it is proposed according to the invention that at least the first component (2, 9) connected to the shaft body (1) in a rotationally fixed manner be subjected to a machining operation and that the at least one second component (3, 8) be screened from the at least one first component (2, 9) during this machining in such a way that chips produced during the machining of the first component (2, 9) do not penetrate into the space between the second component (3, 8) and the shaft body (1) or between the second component (3, 8) and a third component (21) connected to the shaft body (1) in a rotationally fixed manner.