Front Lower Arm Cantilever Support Stiffness and Drainage
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Solution Overview
Problem
Existing vehicle suspension support structures, such as those described in Japanese Patent No. 5698493, face issues with deformation and rust due to repeated loading and moisture accumulation, leading to reduced load-bearing properties and insufficient support stiffness for shock absorbers.
Innovation Solution
A front lower arm design featuring a cantilever tilt on side-rails with an attachment portion joined to the front upper corner of the lower arm body, which has higher stiffness than the upper or side surfaces, and includes a rectangular tubular shape with drainage paths to prevent moisture accumulation and enhance rust resistance, along with a forged ball joint bracket for improved stiffness and peeling resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the support bracket is welded to the upper surface of the lower arm, then the shock absorber can be supported, but the upper surface of the lower arm deforms due to repeated loading
Solution Approach 1:
The patent applies local quality by creating a reinforced region at the attachment portion through welding the shock absorber bracket to the front upper corner portion of the lower arm body. This localized reinforcement concentrates structural strength where needed (at the attachment point) without requiring the entire upper surface to have high stiffness, thus preventing deformation while maintaining load bearing capacity.
2Strength
If the upright plates are welded to the upper surface of the lower arm, then the shock absorber is supported, but moisture accumulates in the space between upright plates causing rust
Solution Approach 1:
The patent extracts the harmful element (moisture) from the system by providing drainage paths that allow water and muddy water to drain out from the internal space of the shock absorber bracket. This prevents moisture accumulation and subsequent rust formation, thereby improving reliability while maintaining the load bearing structure.
3Device complexity
If the support bracket is welded to the side surface of the lower arm, then the structure is simplified, but torsional stress is generated reducing support stiffness
Solution Approach 1:
The patent applies dimensionality change by positioning the attachment portion at the front upper corner portion of the lower arm body, which is a three-dimensional location that optimally resists multi-directional forces including torsional stress. This spatial arrangement provides superior support stiffness compared to simple side surface welding, while the bracket design itself remains relatively simple.
Data Source
AI summary
A front lower arm is tiltably supported, in a cantilever manner, by an outer surface of each of side-rails provided in right and left vehicle regions and extending in a vehicle front-rear direction. The front lower arm includes: a lower arm body; an inner pivot provided at an inner end of the lower arm body in a vehicle right-left direction and supported by the side-rail; and an attachment portion to which a lower end of a shock absorber is attached, and which is joined to an intermediate section of a front upper corner portion of the lower arm body. The intermediate section is an intermediate section of the front upper corner portion in the vehicle right-left direction. A ball joint to which a knuckle is connected is attached to an outer end of the front lower arm in the vehicle right-left direction.