Double Tube Hydraulic Shock Absorber Guide Member Axial Force Alignment
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Solution Overview
Problem
The existing double tube hydraulic shock absorber attachment structure is prone to buckling due to excessive axial force, leading to misalignment of critical components and increased manufacturing costs, especially when the inner tube, valve case, and other components are minimized for weight reduction.
Innovation Solution
A guide member is attached to the top side of the outer and inner tubes to support the piston rod and apply axial force directly on the inner tube, ensuring the leg portions of the base valve contact the lower cap on the line of action of the force, preventing buckling by aligning the base portion and contact portion with the axial force, thus maintaining component alignment and functionality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If the inner tube, valve case, and other components are minimized in thickness for weight reduction, then the weight of the shock absorber is reduced, but the components become more prone to buckling under excessive axial force
Solution Approach 1:
A guide member is introduced as an intermediary component between the bearing member and the inner tube. The guide member receives axial force from the bearing member and transmits it to the inner tube through its lower end, which is in contact with the inner tube. This intermediary structure ensures that the axial force is properly directed along the line of action passing through the contact points of the valve case leg portions with the lower cap, preventing buckling of the thin-walled valve case while maintaining weight reduction benefits
2Device complexity
If the leg portions of the base valve are positioned further inside than the line of extension of the inner tube opening end, then the attachment structure is compact, but excessive axial force causes the valve case to buckle
Solution Approach 1:
The guide member serves as a mediator that redirects the axial force from the bearing member through its lower end contact with the inner tube. This ensures that the force transmission path aligns with the line of action passing through the valve case leg portion contact points on the lower cap, eliminating bending moments that would cause buckling, while allowing the leg portions to remain in their compact internal positioning
3Reliability
If a delicate operation is performed to attach the bearing member to prevent excessive axial force, then the valve case buckling is prevented, but the working hours and manufacturing costs increase
Solution Approach 1:
The guide member is pre-positioned on the inner tube such that its lower end is in contact with the inner tube before the bearing member is attached. This preliminary arrangement ensures that when the bearing member is subsequently attached, the axial force is automatically directed through the guide member along the correct line of action, preventing buckling without requiring delicate or time-consuming adjustment operations during assembly
Solution Approach 2:
The guide member acts as a mechanical intermediary that automatically guides and directs the axial force transmission path. By physically constraining the force transmission through its geometry and contact surfaces, it eliminates the need for delicate manual operations to ensure proper force distribution, thereby maintaining reliability while improving manufacturing efficiency
Data Source
AI summary
A double tube hydraulic shock absorber comprises: an outer tube; an inner tube; a base valve which is fitted and fixed to a base end of the inner tube; a lower cap provided so as to contact a leg portion of the base valve and seal a base end of the outer tube in an oil tight fashion; a piston rod inserted into the inner tube so as to be capable of an axial reciprocation; and a guide member attached to a top side of the outer tube and the inner tube so as to support the piston rod and apply an axial force on the inner tube. In this double tube hydraulic shock absorber, the leg portion of the base valve and the lower cap contact each other on a line of action of the axial force that is applied toward the base end of the inner tube.