Piston Rod and Solenoid Case Joining to Prevent Edge Deformation
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Solution Overview
Problem
In the conventional plastic flow joining method, the deformation of the piston rod's circumferential edge portion occurs due to the processing force applied during the joining of the piston rod and solenoid case, especially when a cable insertion hole is present.
Innovation Solution
A joined body is manufactured by fitting the piston rod's one-end portion into a fitted hole of the solenoid case, causing the solenoid case material to plastically flow into grooves on the piston rod's surface, with a first groove having a greater depth than a second groove, distributed axially apart, to distribute the processing force effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the conventional plastic flow joining method is used to join the piston rod and solenoid case, then the joining strength is improved, but the circumferential edge portion of the piston rod opening is deformed due to processing force
Solution Approach 1:
The single groove is divided into multiple grooves (first groove and second groove) arranged axially along the piston rod. This segmentation distributes the material flow paths, reducing the concentration of processing force on any single location and preventing deformation of the piston rod opening while maintaining effective joining strength.
Solution Approach 2:
The groove arrangement extends from a single radial location to multiple axial locations along the piston rod. By distributing grooves in the axial dimension rather than concentrating them at one location, the processing force is dispersed along the length of the piston rod, preventing localized deformation at the opening.
2Strength
If a single deep groove is used for plastic flow joining, then the joining strength is improved, but the reaction force causes deformation of the pressure-receiving portion
Solution Approach 1:
The single deep groove is segmented into multiple shallower grooves distributed axially. This segmentation divides the total material flow requirement across multiple locations, reducing the reaction force at any single groove while collectively maintaining sufficient joining strength through the combined effect of all grooves.
Solution Approach 2:
Each groove is designed with appropriate local depth and positioning along the piston rod. The grooves are not uniformly deep but are optimized at different axial locations, creating local quality variations that distribute stress and reaction forces effectively while ensuring adequate material flow for strong joining.
3Manufacturing precision
If the piston rod is designed with a flange portion to receive processing force, then the deformation is prevented, but the shock absorber size increases
Solution Approach 1:
The flange portion is extracted/removed from the piston rod design. Instead of adding a flange structure to receive processing force, the invention uses the groove distribution pattern to inherently manage and distribute the processing force along the piston rod body, eliminating the need for additional flange structure and reducing overall shock absorber size.
Solution Approach 2:
The piston rod itself serves the dual function of both the joined component and the force distribution structure. By distributing grooves axially along the piston rod, the piston rod's own structure is utilized to manage processing forces without requiring separate force-receiving features like flanges, making the system more compact.
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 method prevents deformation of the piston rod's pressure-receiving portion by reducing the reaction force and allowing for a more stable joining process, while also reducing the size of the shock absorber by eliminating the need for a flange portion.
Implementation Method 1
pressing a material of the counterpart member to thus cause the material to plastically flow into a groove provided on a circumferential surface of the rod-like member
Data Source
AI summary
A first annular groove is filled with a material of a solenoid case and a first joined portion is formed after a second annular groove is filled with the material of the solenoid case and a second joined portion is formed. This allows a load applied to a piston rod when the material of the solenoid case flows into the first annular groove to be partially received by the second joined portion, thereby contributing to reducing a reaction force received by the piston rod and thus preventing the deformation of an upper-end portion of the piston rod due to the reaction force received by the piston rod.