Pump Assembly Cam Rider Angular Constraint via Intermediary Plate
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Solution Overview
Problem
Existing pump assemblies for common rail diesel engines face issues with the cam rider tilting about its axis, leading to wear, damage, and potential catastrophic failure due to inadequate retention mechanisms, and existing solutions like guide devices can jam.
Innovation Solution
A pump assembly with a coupling plate that constrains the cam rider to move along linear paths, preventing angular movement and ensuring it follows a circular path, using an Oldham-style coupling concept to lock angular movement between non-rotating elements while allowing linear translation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a guide device in the form of a pin is used to prevent cam rider tilt, then angular movement is constrained, but the pin may become jammed within the indentation
Solution Approach 1:
A plate is introduced as an intermediary component between the cam rider and the housing. The plate carries the cam rider and is constrained by the housing, preventing the cam rider from tilting directly against the housing walls. This intermediary plate eliminates the jamming issue by providing a separate, dedicated structure for angular constraint.
Solution Approach 2:
The constraint system is segmented into multiple independent components: the housing constrains the plate's linear movement, while the plate constrains the cam rider's angular movement. This segmentation allows each component to perform its specific constraint function without interfering with the other, preventing jamming.
2Device complexity
If the cam rider is allowed to move freely, then the structure is simple, but angular movement causes wear, damage, and catastrophic failure
Solution Approach 1:
The plate serves as a mediator that provides angular constraint through a simple, elegant mechanism. Rather than complex direct constraints between the cam rider and housing, the plate intermediates this relationship, providing reliable angular stability with minimal structural complexity.
Solution Approach 2:
The constraint mechanism operates in a different dimensional approach: instead of directly constraining the cam rider's angular movement through complex mechanical stops, the system uses the plate's linear movement constraints to indirectly control the cam rider's angular position, effectively solving the problem in a different dimensional space.
3Adaptability or versatility
If angular movement of the cam rider occurs, then the cam rider can accommodate manufacturing tolerances, but contact concentration leads to accelerated wear and potential failure
Solution Approach 1:
The plate acts as an intermediary that eliminates harmful angular contact concentrations. By constraining the cam rider's angular movement through the plate's linear constraints, the system prevents localized contact stress and wear while still allowing the cam rider to function effectively within its operational parameters.
Data Source
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AI summary
A pump assembly for an internal combustion engine comprising a pump housing (40), at least one pumping arrangement having a pumping plunger (56, 58) for pressurising fluid within a pump chamber; a drive shaft (46) carrying a cam (48) and a cam rider (50) which cooperates with the pumping arrangement to drive plunger movement along a plunger axis; and a plate (74; 174; 274; 374) coupled, on one side (74b), to the cam rider (50) and, on its other side (74a), to the housing (40) by coupling means (84, 86, 80, 82; 84, 180; 280, 286; 380, 480).The coupling means is arranged to constrain movement of the plate (74; 174; 274; 374) relative to the housing (40) in a first linear direction and to constrain movement of the cam rider (50) relative to the plate in a second linear direction, and to prevent angular movement of the cam rider (50) about its axis. Wear of the plunger, or of any intermediate component between the cam rider and the plunger, can be reduced as the cam rider is unable to tilt about its axis.