Elastomer Wedge for Cam Axial Positioning and Shock Damping
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Solution Overview
Problem
Existing high-pressure fuel supply pump arrangements in motor vehicles either increase the engine's size, require additional complex components, or compromise efficiency due to space constraints and mechanical stresses from engine acyclisms.
Innovation Solution
A high-pressure fuel supply pump arrangement with a cam actuated by the crankshaft, featuring an elastic connecting ring made of elastomer to maintain axial position and absorb shocks, allowing for compact design and easy maintenance while minimizing size and complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a cam is fixed coaxially to the crankshaft to actuate the high-pressure pump, then the pump can be directly driven by the crankshaft, but the space between the crankshaft arms must be pushed back which increases the engine size
Solution Approach 1:
The cam is positioned at the longitudinal end of the crankshaft rather than coaxially between the arms, changing the spatial arrangement from a radial/diametral position to an axial/end position. This dimensional shift allows the cam to be driven directly by the crankshaft without increasing the lateral space between crankshaft arms, thus maintaining compact engine dimensions while achieving direct drive efficiency.
2Ease of repair
If the cam is mounted with a slip fit for easy disassembly, then maintenance is simplified, but the cam undergoes axial displacements due to engine acyclisms which compromises reliability
Solution Approach 1:
An elastomer ring is introduced as a flexible component between the cam and the crankshaft end. This elastomer ring provides elastic retention that allows the cam to be easily mounted and dismounted while simultaneously compensating for axial displacements caused by engine acyclisms. The elastic material absorbs the dynamic forces and maintains stable axial positioning of the cam during operation, thus resolving the contradiction between ease of repair and operational reliability.
3Length of moving object
If the high-pressure pump is arranged at one end of the crankshaft facing the coupling face, then the longitudinal dimension is reduced, but the available space is very small requiring additional intermediate accessories which reduces pump efficiency
Solution Approach 1:
The cam and the high-pressure pump are merged into a single integrated unit, with the cam serving as both the drive element and the pump body. This eliminates the need for intermediate transmission accessories such as gears, belts, or additional shafts that would be required to transmit power from the crankshaft to a separately mounted pump. The direct integration reduces device complexity while maintaining the compact longitudinal arrangement.
4Ease of operation
If a shaft parallel to the crankshaft is added to drive the pump, then the pump can be actuated by a cam, but the block requires additional shaft accommodation which increases molding complexity and machining requirements
Solution Approach 1:
The crankshaft is given a multi-functional role by positioning the cam directly on its longitudinal end, allowing it to simultaneously serve as both the power transmission shaft and the cam drive shaft. This eliminates the need for a separate parallel shaft that would require additional bearing housings, support structures, and complex machining operations in the engine block. The crankshaft's existing structure is utilized to perform the additional cam actuation function, simplifying manufacturing.
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
The solution effectively maintains the cam's axial position, reduces engine size, and dampens mechanical stresses, ensuring efficient fuel supply and easy maintenance without increasing the engine's longitudinal dimension or complexity.
Implementation Method 1
The connecting ring is elastic... makes it possible to absorb the shocks due to the acyclisms of the operation of the engine and makes it possible to maintain the cam in the axial position
Implementation Method 2
the connecting ring is made of elastomer... By virtue of its elastic characteristics, the connecting ring ensures optimum retention of the drive cam in place
Data Source
Figure 1~2
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Figure 5~6
AI summary
The invention relates to a system for attaching an actuating cam (15) arranged about a crankshaft (10) of a heat engine of a motor vehicle surrounding a crankshaft coupling end (111) axially bordered by a flywheel (11), said crankshaft being housed in a cylinder case (12) of the engine, said actuating cam (15) including a cylindrical bearing portion (16) extended radially by an oblong plate (23), characterised in that the cylindrical bearing portion (16) of the actuating cam (15), mounted slidingly surrounding the coupling end (111) of the crankshaft, has a linking ring (40) for holding said cam axially with the crankshaft.