Rotary Damper Tapered Partition Wall for Stable Oil Supply
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Solution Overview
Problem
Conventional rotary dampers with casting cylinders suffer from external shrinkage-induced recesses at the partition wall distal end, leading to gaps between the partition wall and shaft, which compromise the damper's performance by reducing oil supply to valves and braking force.
Innovation Solution
The rotary damper features a tapered shape at the distal end of the partition wall and shaft, achieved through a casting process using a mold with a tapered part and dent, preventing external shrinkage and gap expansion, and includes a check valve system to manage oil flow effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the partition wall and shaft part are designed with straight shapes (constant outer/inner diameter), then the manufacturing process is simple, but external shrinkage during casting creates recesses that expand gaps and lower damper characteristics
Solution Approach 1:
The patent applies parameter changes by transitioning from straight shapes (constant diameter) to tapered shapes (variable diameter) for both the partition wall distal end and shaft part. This geometric parameter change compensates for external shrinkage effects during casting, maintaining consistent gap dimensions between the partition wall and shaft part while preserving manufacturing simplicity through standard casting processes.
2Ease of manufacture
If the partition wall includes a recess due to external shrinkage, then the casting process is straightforward, but the gap between partition wall and shaft part expands, reducing oil supply to valves
Solution Approach 1:
The patent changes the geometric parameters of the partition wall distal end to a tapered shape, which compensates for external shrinkage during casting. This prevents recess formation that would otherwise expand gaps and reduce oil supply to valves, thereby maintaining adequate oil quantity for valve operation while keeping the casting process straightforward.
3Device complexity
If the partition wall has a straight shape, then the mold design is simple, but recesses form on the distal end surface due to shrinkage, lowering braking force
Solution Approach 1:
The patent modifies the mold design to create a tapered shape at the distal end of the partition wall through parameter changes in the molding portion geometry. This tapered configuration compensates for shrinkage during solidification, preventing recess formation that would expand gaps and reduce braking force, while maintaining reasonable mold design complexity.
4Ease of manufacture
If the shaft part is straight-shaped, then the rotor manufacturing is simple, but gaps expand due to partition wall recesses, compromising damper characteristics
Solution Approach 1:
The patent applies parameter changes to the shaft part design by transitioning from a straight shape (constant outer diameter) to a tapered shape (variable outer diameter). This geometric modification compensates for partition wall recesses caused by external shrinkage, maintaining consistent gap dimensions and preserving damper characteristics while keeping rotor manufacturing simple through standard casting methods.
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 ensures a consistent oil supply to valves, stabilizes operation time under varying loads, and maintains braking force by preventing gap expansion between the partition wall and shaft, reducing resistance and improving overall damper performance.
Implementation Method 1
external shrinkage occurs due to shrinkage at the time of solidification of a molten metal
Data Source
AI summary
The present invention provides a rotary damper comprising a cylinder (10) having a partition wall (13), and a rotor (20) having a shaft part (21) facing the partition wall, wherein the cylinder is a casting, and a distal end of the partition wall and the shaft part have a tapered shape. According to the present invention, it is possible to prevent expansion of a gap formed between the partition wall and the shaft part.