Bump Stopper Cap Rib Segmentation for Press Fit Seating
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Solution Overview
Problem
The existing bump stopper caps deform into a skirt shape during press fitting, leading to a clearance between the seating surface and the cylinder main body, causing stress concentration and reduced endurance when subjected to loads from the bump stopper.
Innovation Solution
The interference portion is formed a predetermined distance away from the seating surface in the axial direction of the circular-cylinder portion, allowing for elastic deformation and proper seating of the bump stopper cap, preventing deformation into a skirt shape and enhancing fixation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the interference portion extends to the connecting portion connected with the top board portion, then the fixation strength to the cylinder main body is improved, but the circular-cylinder portion deforms into a skirt shape during press fitting
Solution Approach 1:
The interference portion is segmented into a specific axial range that excludes the connecting portion. By defining the interference portion to extend only from the bottom end toward the top end within a predetermined axial distance, the rigid interference zones are separated from the flexible connecting portion, allowing the connecting portion to deform elastically during press fitting without creating a skirt shape
Solution Approach 2:
Different regions of the circular-cylinder portion are assigned different functional qualities. The interference portion region (within predetermined axial distance from bottom end) is designed for rigid fixation, while the connecting portion region (beyond this distance) is designed for elastic deformation capability. This local differentiation allows simultaneous achievement of strong fixation and proper deformation behavior
2Strength
If the interference portion extends to the connecting portion, then the press fit fixation is strengthened, but stress concentration occurs in the connecting portion under load
Solution Approach 1:
The structure is segmented into a rigid fixation zone (interference portion) and a flexible load-absorbing zone (connecting portion). By limiting the interference portion to a predetermined axial distance from the bottom end, the connecting portion remains free of interference and can elastically deform to absorb stress, preventing stress concentration and improving endurance
Solution Approach 2:
The connecting portion is designed in advance as an elastic cushion zone that can deform beforehand to absorb and distribute loads from the bump stopper. This pre-designed flexible region acts as a stress buffer, preventing stress concentration in the rigid interference portion and improving the overall reliability under dynamic loading conditions
3Strength
If the interference portion is formed with high rigidity, then the fixation to cylinder main body is improved, but proper deformation outward in radial direction cannot be acquired during press fit
Solution Approach 1:
The press fit process is segmented into two functional zones: a rigid interference portion zone that provides strong fixation, and a flexible connecting portion zone that enables proper deformation. By spatially separating these functions through the predetermined axial distance limitation, the rigid interference portions can be properly formed without preventing the necessary deformation of the connecting portion during manufacturing
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 design improves the endurance of the bump stopper cap by preventing deformation and ensuring proper seating, reducing stress concentration and enhancing the cap's ability to withstand loads without creating a clearance.
Implementation Method 1
The interference portion which squeezes the outer circumference surface 110a of the cylinder main body 110 inward in a radial direction is formed in the inner circumference surface 210a of the circular-cylinder portion 210
Data Source
AI summary
The endurance of a bump stopper cap is improved by preventing a clearance from being generated between a back face of a top board portion of the bump stopper cap and a nib surface of a cylinder main body. A non-interference region in which a rib is not formed is disposed on the top side of a circular-cylinder portion of the bump stopper cap, and an interference region where the rib is formed is disposed on the opening side from this non-interference region. Since the non-interference region can be deformed freely in association with the deformation of the interference region when the bump stopper cap is pressed fit at the nib of the cylinder main body, a seating surface which is the back face of the top board portion can be properly seated on the nib surface of the cylinder main body.