Segmented Subframe Bush for Collision Separation and Assembly Protection
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Solution Overview
Problem
Existing subframe mounting bushes face challenges in achieving both collision performance and durability, as they are prone to damage during assembly and fail to separate properly from the subframe during collisions due to excessive friction and elastic restoring forces.
Innovation Solution
The subframe mounting bush is designed with an outer pipe divided into multiple parts, an inner pipe, and a buffering rubber, all divided vertically, allowing for flexible separation during collisions while maintaining vibration insulation features. The outer pipe is made of plastic, and the rubber is divided into parts of different materials to enhance separation and durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the outer pipe is formed using plastic to improve collision performance, then the mounting bush can be easily separated from the subframe at the time of collision, but the outer pipe is damaged during assembly due to friction and deformation
Solution Approach 1:
The outer pipe is divided into an upper pipe and a lower pipe that are press-fitted into the bush cup separately. This segmentation reduces the friction and deformation stress on each individual pipe section during assembly, preventing damage while maintaining the plastic material's collision separation capability.
Solution Approach 2:
A guide groove is formed on the inner surface of the bush cup, and a guide protrusion is formed on the outer surface of the pipes. This guide structure acts as an intermediary that guides the pipes into the correct position during assembly, reducing misalignment and friction-induced damage.
2Strength
If the mounting bush is formed in an oval shape to secure separation force, then the position is fixed during assembly, but the mounting bush is not separated from the subframe at the time of collision due to elastic restoring force of the buffering rubber
Solution Approach 1:
The mounting bush is divided into upper and lower pipes that can separate independently during collision. This segmentation allows the bush to maintain strength during assembly while enabling effective separation at collision, overcoming the limitation of the oval shape design.
Solution Approach 2:
Instead of relying on the oval shape's elastic restoring force to provide separation, the design inverts the approach by using a circular cross-section with guide grooves and protrusions. The separation is achieved through the fracture of the guide protrusion or guide groove engagement, rather than elastic restoration.
3Stability of the object's composition
If the hook is formed at the upper end of the outer pipe to be hooked onto the bush cup, then the position is fixed, but deformation occurs inwardly by protrusion amount causing damage due to friction
Solution Approach 1:
The guide groove and guide protrusion act as intermediary elements that provide position fixation during assembly. The guide groove receives the guide protrusion, allowing the pipe to be securely positioned without the need for a hook that causes friction damage.
Solution Approach 2:
The harmful hook structure is extracted and replaced with a guide groove-protrusion system. This removes the source of friction damage while maintaining the necessary position fixation function during assembly.
4Stability of the object's composition
If the flange is formed at the lower end of the outer pipe to contact the bush cup, then the position is fixed, but the flange is fractured at collision preventing separation
Solution Approach 1:
The lower pipe is separated from the upper pipe, with only the upper pipe being press-fitted into the bush cup. This segmentation ensures that the connection is maintained during assembly while allowing the lower pipe to separate freely during collision, improving collision performance.
Solution Approach 2:
The flange structure that causes fracture and prevents separation is extracted. Instead, the upper pipe's press-fit connection provides position fixation, while the segmented design allows the lower pipe to separate during collision without flange interference.
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 configuration ensures smooth separation of the subframe mounting bush from the subframe during collisions, minimizes damage during assembly, and maintains vibration insulation performance, addressing both collision and durability issues.
Implementation Method 1
a buffering rubber 36 interposed between the outer pipe 32 and the inner pipe 34
Implementation Method 2
the outer pipe 32 has been formed using plastic to allow the mounting bush 30 to be easily separated from the subframe
Data Source
AI summary
A subframe mounting bush my include an outer pipe provided in a subframe and divided into at least two or more outer divided parts in a vertical direction, an inner pipe inwardly spaced apart from the outer pipe by a predetermined gap and divided into at least two or more inner divided parts in the vertical direction, and a buffering rubber interposed between the outer pipe and the inner pipe and divided into at least two or more rubber divided parts in the vertical direction.