Cam Follower Roller with Composite Body for Inertia Reduction
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Solution Overview
Problem
Cam follower roller devices in automotive and industrial applications, particularly in fuel injection pumps and rocker systems, suffer from increased inertia due to their heavy construction, leading to potential sliding issues and excessive pressure contact with cams.
Innovation Solution
A multi-material cam follower roller device is designed with a lightweight body of lower density material between the inner and outer axial portions, reducing inertia and incorporating a flexible body for angular tilting to minimize edge stresses and pressure contact, while using overmoulding and recesses for enhanced cohesion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a massive or solid roller is used in the cam follower roller device, then the structural strength and durability are improved, but the weight and rotational inertia of the device increase
Solution Approach 1:
The roller is constructed as a composite structure with an inner axial portion, an outer axial portion, and a body made of different materials. The body has lower density than the axial portions, creating a lightweight core that reduces overall weight and rotational inertia while the denser axial portions maintain contact strength with the pin and cam.
Solution Approach 2:
The roller is divided into three distinct segments: an inner axial portion mounted on the pin, an outer axial portion contacting the cam, and a body radially interposed between them. This segmentation allows each part to be optimized for its specific function - the axial portions for strength and contact, the body for lightweight construction.
2Strength
If a massive roller is used to ensure durability, then the contact strength with the cam is improved, but the pressure contact and edge stresses increase
Solution Approach 1:
The density parameter of the roller material is changed by using a low-density material for the body while maintaining higher density materials for the inner and outer axial portions. This parameter change reduces the overall weight and pressure contact with the cam while preserving contact strength at the critical interfaces.
Solution Approach 2:
Different regions of the roller are assigned different material densities - the inner and outer axial portions use higher density materials for strength at contact points, while the body uses lower density material to reduce overall pressure. This local quality differentiation optimizes both strength and pressure distribution.
3Weight of moving object
If the roller weight is reduced for lightweight construction, then the rotational inertia and pressure contact are decreased, but the structural strength may be compromised
Solution Approach 1:
The composite roller structure uses materials with different densities strategically placed - low-density material in the body for weight reduction, and high-density materials in the axial portions for maintaining structural strength and contact durability.
Solution Approach 2:
By segmenting the roller into functional zones (inner axial portion, body, outer axial portion), the design allows weight reduction in the body while preserving strength in the critical contact zones, resolving the contradiction between lightweight construction and structural strength.
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 results in a lighter, more stable cam follower roller device with reduced rotational inertia, lower risk of sliding, and decreased pressure contact, enhancing operational efficiency and durability.
Implementation Method 1
The density of the material of said body is smaller than that of the material(s) of the inner and outer axial portions
Implementation Method 2
the body of the roller is made from a flexible material. With such embodiment, an angular tilting of the outer axial portion of the roller with respect to the inner axial portion may be obtained
Implementation Method 3
the body of the roller is overmoulded onto the outer and inner axial portions. To further increase the cohesion between the overmoulded body and the inner and/or outer axial portions
Data Source
Figure 1
Figure 2~3
AI summary
The cam follower roller device comprises a tappet body (12), a pin (14) mounted into said tappet body, and a roller 16 mounted on said pin and comprising an inner bore (24b) and an outer surface (22a). The roller (16) comprises an inner axial portion (24) provided with said inner bore, an outer axial portion (22) provided with said outer surface, and a body (26) radially interposed between the inner and outer axial portions, the density of the material of said body being smaller than that of the material(s) of the inner and outer axial portions