Cam Follower Roller Insert Stiffener Design
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Solution Overview
Problem
The increasing pressure in fuel injection pumps for internal combustion engines leads to higher piston loads on cam follower roller devices, causing insert deformations and reducing reliability, which existing designs fail to adequately address.
Innovation Solution
Incorporating stiffeners between the central core and side tabs of the insert within the cam follower roller device to increase stiffness, allowing for reduced thickness and weight while maintaining structural integrity, and using anti-rotation and retaining means to secure the insert within the tappet body.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If the insert thickness is reduced to decrease weight, then the weight of the cam follower roller device decreases, but the insert becomes more susceptible to deformations under piston load
Solution Approach 1:
The patent applies local quality by adding stiffeners at specific locations (between the central core and side tabs) rather than uniformly increasing the entire insert thickness. This localized reinforcement provides the necessary structural support and deformation resistance only where the piston load is applied, while keeping other areas of the insert thinner and lighter.
Solution Approach 2:
The insert is constructed as a composite structure combining a central core, side tabs, and stiffeners. This composite design allows different regions to have different thicknesses and structural properties, optimizing the balance between weight reduction and deformation resistance under piston load.
2Strength
If the insert thickness is increased to increase stiffness and reduce deformation, then the deformation resistance improves, but the weight of the cam follower roller device increases
Solution Approach 1:
Instead of uniformly increasing insert thickness throughout, the patent applies stiffeners only at the critical regions where piston load is transmitted (between the central core and side tabs). This localized approach provides maximum deformation resistance where needed while minimizing additional weight.
Solution Approach 2:
The insert is segmented into distinct functional components: a central core for structural support, side tabs for pin mounting, and stiffeners for load distribution. This segmentation allows each component to be optimized independently for its specific function, achieving high stiffness-to-weight ratio.
3Productivity
If higher fuel pump pressure is used to improve fuel efficiency, then fuel injection performance improves, but the piston load on the insert increases causing deformations
Solution Approach 1:
The composite structure of the insert with its central core, side tabs, and integrated stiffeners creates a rigid framework that can withstand the high piston loads generated by elevated fuel pump pressures, preventing deformations that would compromise injection performance.
Solution Approach 2:
The stiffeners are positioned at the exact locations where piston load is applied to the insert, providing localized reinforcement that enables the insert to withstand high fuel pump pressures without deforming, thus maintaining injection performance.
Data Source
Figure 1~2
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Figure 5~6
AI summary
The cam follower roller device comprises a tappet body 12, an insert 18 mounted in the tappet body and provided with a central core 24 and with at least two side tabs 26, 28, a pin 14 mounted at least on the tabs of the insert, and a roller 16 mounted on said pin. The insert 18 8 further comprises at least one stiffener 44, 46 disposed between the core 24 and each tab 26, 28.