Plastic Clutch Pedal Arm Rib Structure for Stress Concentration
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Solution Overview
Problem
Conventional plastic clutch pedals are structurally weak due to stress concentration at the bent connection portion between the pedal arm and the master cylinder, leading to a high risk of breaking during operation.
Innovation Solution
A vehicle pedal apparatus with a pedal arm made of plastic, featuring a sideways bent lower portion and an indented upper portion, incorporating internal ribs and a spring mechanism for enhanced strength and durability, distributing stress evenly across the arm.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a plastic pedal arm is designed with a long bent connection portion between pad and master cylinder, then formability and weight reduction are improved, but structural strength deteriorates due to stress concentration at the bent portion
Solution Approach 1:
The patent applies local quality by adding ribs (first rib, second rib, third rib) at specific locations within the pedal arm structure. These ribs are positioned to provide localized reinforcement at the bent connection portion where stress concentration occurs, while maintaining the overall plastic construction and formability of the pedal arm.
Solution Approach 2:
The patent creates a composite structure within the plastic pedal arm by incorporating reinforcing ribs that form a composite reinforcement system. The ribs create internal structural support within the plastic material, effectively combining the plastic base material with structural reinforcement elements to achieve both formability and strength.
2Strength
If steel is used for clutch pedal, then strength is improved, but weight and raw material cost increase
Solution Approach 1:
The patent changes the material parameter from steel to plastic, and compensates for the lower inherent strength of plastic by modifying the structural parameters through the addition of ribs. This allows achieving adequate strength with a lighter material, thus reducing weight while maintaining structural integrity.
Solution Approach 2:
The patent segments the pedal arm into functional regions with different structural characteristics - the bent connection portion receives additional rib reinforcement, while other portions maintain simpler plastic construction. This segmented approach optimizes strength where needed while preserving weight reduction benefits of plastic elsewhere.
3Shape
If the pedal arm is bent sideways to extend in lateral direction, then spatial arrangement and formability are improved, but stress concentration at bent portion increases leading to breakage
Solution Approach 1:
The patent applies beforehand cushioning by pre-reinforcing the bent connection portion with multiple ribs before stress is applied during operation. The first rib, second rib, and third rib are built into the structure in advance to cushion and distribute the stress that will occur during pedal operation, preventing breakage before it can occur.
Data Source
AI summary
A vehicle pedal apparatus includes a pedal member installed to be fixed to a dashboard; and a pedal arm rotatably connected to pedal member, elongated in a vertical direction, and including a lower portion that is bent sideways with respect to a front-and-rear direction of a vehicle body, to extend in a first lateral direction and an upper portion that has a first side indented in a second lateral direction opposite to the first lateral direction.