Cam Roller Pin Transverse Grooves Reduce Contact Pressure
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Solution Overview
Problem
High loading on cam rollers in pumps causes bending of roller pins without corresponding bending of cam rollers, leading to non-uniform contact pressure and localized damage, requiring a 'run-in' period and use of softer metals to reduce wear, which shortens the operating life of tappet assemblies.
Innovation Solution
The introduction of grooves on roller pins allows for localized bending, improving contact and interface uniformity between cam rollers and pins, reducing peak contact pressure and enabling the use of stronger materials without increasing wear on cam rollers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the roller pin is made from stronger materials to increase durability, then the strength and load-carrying capacity improve, but the contact pressure becomes more non-uniform causing localized damage and wear
Solution Approach 1:
The roller pin incorporates circumferential grooves at specific locations to create localized flexibility zones. These grooves allow the roller pin to bend locally at the grooves while maintaining overall structural strength, thereby distributing contact pressure more uniformly across the cam roller interface and preventing localized damage.
Solution Approach 2:
The invention changes the structural parameter of the roller pin by introducing grooves that modify its bending characteristics. This allows the roller pin to transition from a rigid structure to one with controlled local flexibility, enabling it to conform to the cam roller profile and distribute contact pressure more evenly while maintaining high strength materials.
2Object-affected harmful factors
If softer metals are used for the roller pin to reduce wear, then the wear rate decreases, but the operating life is reduced due to increased deformation and faster wear under high contact pressure
Solution Approach 1:
The roller pin uses harder materials for the bulk structure to ensure durability and load-carrying capacity, while introducing localized grooves that provide controlled flexibility. This allows the majority of the roller pin to maintain high strength and resistance to deformation, while the grooved regions accommodate bending stresses without causing excessive wear or failure.
Solution Approach 2:
The roller pin can be constructed with composite material properties - the bulk material provides high strength and wear resistance, while the grooved regions create zones of controlled compliance. This composite approach allows the roller pin to simultaneously achieve high strength, reduced wear, and improved contact pressure distribution.
3Object-affected harmful factors
If a run-in period is implemented to reduce non-uniform contact pressure, then the contact pressure distribution improves, but the time required for assembly commissioning increases
Solution Approach 1:
The grooves are pre-formed during manufacturing to create the flexibility zones needed for uniform contact pressure distribution. This preliminary structuring eliminates the need for a run-in period, as the roller pin is pre-configured to conform to the cam roller profile from the start, thereby reducing commissioning time while achieving proper contact pressure distribution.
4Object-affected harmful factors
If the roller pin is made more flexible to improve contact uniformity, then the contact pressure distribution improves, but the load-carrying capacity and durability decrease
Solution Approach 1:
The roller pin maintains high overall strength through its bulk material and geometry, while introducing localized grooves that provide flexibility only where needed for contact pressure distribution. The grooves are positioned to allow bending at specific locations without compromising the overall structural integrity and load-carrying capacity of the roller pin.
Solution Approach 2:
The roller pin structure is segmented by the grooves into regions of different stiffness. The grooved zones provide local flexibility for contact conformity, while the ungrooved sections maintain high rigidity for load transmission. This segmentation allows the roller pin to simultaneously achieve good contact pressure distribution and high load-carrying capacity.
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 solution reduces or eliminates the need for a 'run-in' period, extends the operating life of tappet assemblies, and allows for the use of more durable materials by distributing contact pressure uniformly, preventing excessive wear and improving the load-carrying capacity of cam rollers.
Implementation Method 1
The introduction of grooves on roller pins allows for localized bending, improving contact and interface uniformity between cam rollers and pins
Data Source
AI summary
A roller pin for carrying a cam roller in a tappet assembly is provided. The roller pin providing reduced run in time and reduced peak and localized contact pressure between the cam roller and roller pin. The roller pin comprises a substantially cylindrical shaft having a length, a first end and a second end. The length extends from the first end to the second end. The shaft includes a plurality of grooves axially spaced apart and extending in a direction being transverse to the length. The plurality of grooves located proximate the first and second ends and extending only partially the circumference of the shaft.