Vehicle Subframe Bush Positioning and Vibration Control
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Solution Overview
Problem
Existing subframe structures for vehicles limit the positioning of the lower arm relative to the cross member, restricting the geometry of the suspension arm and not effectively suppressing vibrations caused by the swinging movement of the lower arm.
Innovation Solution
A subframe structure that includes a cylindrically shaped bush with a central axis aligned with the rotational axis, allowing the lower arm to be positioned as low as possible with respect to the cross member, and a reinforcing member such as an attaching plate that secures the toe angle changing device to the cross member, enhancing structural integrity and reducing vibrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If the bolt insertion hole is positioned at a lower location in the suspension bracket, then the lower arm can be positioned lower relative to the cross member, but the structural strength and stability of the cross member deteriorates
Solution Approach 1:
A reinforcing member is introduced as an intermediary element between the lower arm attaching portion and the toe angle changing device attaching portion of the cross member. This reinforcing member bridges the structural gap created by positioning the attaching hole at a lower location, thereby maintaining structural strength while enabling the lower arm to be positioned lower relative to the cross member.
2Adaptability or versatility
If the lower arm is positioned lower relative to the cross member, then the freedom of geometry of the suspension arm is improved, but vibrations caused by swinging movement of the lower arm increase
Solution Approach 1:
The reinforcing member serves as a mediator that connects the lower arm attaching portion to the toe angle changing device attaching portion, providing structural support that suppresses vibrations generated by the swinging movement of the lower arm. This allows the lower arm to be positioned lower while maintaining sufficient structural rigidity to control vibrations.
3Reliability
If a reinforcing member is added to bridge between the device attaching portion and the attaching hole, then the structural integrity and vibration suppression are improved, but the device complexity increases
Solution Approach 1:
The reinforcing member is designed to perform multiple functions simultaneously: it reinforces the cross member structure, suppresses vibrations from lower arm swinging, and provides a mounting surface for the toe angle changing device. By consolidating these functions into a single component, the overall device complexity is minimized while achieving the desired structural integrity and vibration control.
Data Source
AI summary
A subframe structure for a vehicle attaches a lower arm to a cross member extending in the vehicle width direction, the lower arm extending in the vehicle width direction and being configured to move rotationally about a predetermined rotational axis to support a knuckle such that the knuckle can be displaced in the vehicle height direction. The subframe structure includes a cylindrical bush whose central axis is aligned with the rotational axis. The cross member has an arm attaching hole that retains the bush such that the bush is rotatable about the rotational axis. The lower arm is fixed to the bush at a position on the rotational axis. The arm attaching hole opens downward in the vehicle height direction. The cross member retains the bush such that a part of the outer surface of the bush protrudes downward in the vehicle height direction beyond a lower end portion.