Vehicle Control Pedal Tubular Arm Segmentation Welding
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Solution Overview
Problem
Existing control pedals for vehicles face challenges in achieving a balance between stiffness, weight, safety, and manufacturability, particularly in ensuring uniform wall thickness and ease of manufacturing, especially when forces on the pedal arm have varying directions of application.
Innovation Solution
A control pedal with a tubular structure is created by joining two arm parts with open cross-sections, where one part forms the foot pad and hinge bush, allowing for high stiffness and mechanical strength while optimizing weight through precise moulding and welding, ensuring the pedal remains operational even if the joint fails.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If gas- or water-assisted moulding technique is used to create tubular pedal arm from solid body, then stiffness and mechanical strength are improved, but manufacturing complexity and difficulty in ensuring uniform wall thickness increase
Solution Approach 1:
The pedal arm is divided into two separate arm parts that are moulded independently and then joined together. This segmentation allows each part to be manufactured using standard injection moulding techniques without requiring complex gas- or water-assisted moulding, while still achieving the desired tubular structure and mechanical properties.
Solution Approach 2:
The two arm parts are pre-formed by injection moulding with the tubular structure already incorporated in the mould design. This preliminary formation of the tubular shape during standard moulding eliminates the need for subsequent material removal operations and ensures uniform wall thickness from the outset.
2Strength
If metal insert is added by insert moulding to increase stiffness, then stiffness is improved, but cost and weight increase
Solution Approach 1:
The patent changes the material parameter from metal to plastic for the insert, specifically using a plastic material with a melting point above 200°C. This parameter change allows the insert to be formed by injection moulding rather than requiring expensive metal moulding and insert moulding operations, reducing both cost and weight while maintaining the stiffness-enhancing function.
Solution Approach 2:
The patent uses a composite structure combining the pedal arm body with a plastic insert material that has different thermal properties (melting point above 200°C). This composite approach allows the insert to provide structural reinforcement and stiffness improvement without the weight and cost penalties of metal inserts.
3Strength
If ribs are arranged to increase moment of inertia and stiffness, then stiffness is improved, but manufacturing complexity increases due to proper arrangement requirements
Solution Approach 1:
Instead of adding complex three-dimensional rib structures that require precise arrangement, the patent uses a two-dimensional planar insert formed by injection moulding. This insert is inserted into a cavity in the pedal arm, providing stiffness enhancement through a simpler geometric approach that is easier to manufacture.
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 design combines high stiffness and mechanical strength with ease of manufacturing and optimized weight, ensuring the pedal is strong, lightweight, and cost-effective, while maintaining safety by allowing continued operation in case of joint failure.
Implementation Method 1
the two arm parts to be joined to each other, preferably by welding
Data Source
Figure 1~2
Figure 3
AI summary
The pedal (10) comprises a pedal arm (12) of plastic material having a tubular structure, with a first arm part (18) having an open cross-section and a second arm part (20) having an open cross-section, which arm parts are produced by moulding separately from each other and are joined to each other by welded joint so as to define the closed cross-section of the pedal arm (12). The pedal (10) further comprises a foot pad (14) that is wholly formed by the first arm part (18).