Slinger Manufacturing via Controlled Mold Roughness and Pressure
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Solution Overview
Problem
Existing rotary seal manufacturing methods incur additional costs and variability in surface roughness, affecting wear and oil film retainability, as they require separate processing steps for achieving optimal surface roughness on slinger components.
Innovation Solution
A manufacturing method involving molding and burring of annular blank materials from dull-finished steel sheet materials, with controlled arithmetical mean roughness and pressure application, to achieve surface roughness within a predetermined range of 0.25 μm to 0.5 μm on slide-contact surfaces, eliminating the need for separate processing steps and ensuring reduced wear and maintained oil film retainability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a separate processing step (fine-rigid particle impact, cutting processing, wet blasting, or shot peening) is used to form an uneven surface on the slide-contact surface, then oil film retainability is improved and running torque is reduced, but manufacturing cost increases
Solution Approach 1:
The patent combines the surface unevenness formation into the press-molding process itself by using a mold with a specific roughness (Ra 0.03-0.07 μm). This merging of the surface treatment function into the molding process eliminates the need for separate processing steps like shot peening or wet blasting, thereby reducing manufacturing cost while maintaining oil film retainability
Solution Approach 2:
The mold surface is prepared in advance with a controlled roughness (Ra 0.03-0.07 μm) before the molding process. This preliminary preparation of the mold surface ensures that the slide-contact surface of the slinger automatically acquires the required unevenness during pressing, eliminating the need for subsequent surface treatment steps
2Ease of manufacture
If press-molding with a dull-finished steel sheet material is used to reduce manufacturing cost, then manufacturing cost is reduced, but surface roughness control becomes difficult affecting wear and oil film retainability
Solution Approach 1:
The patent specifies precise parameter ranges for the mold surface roughness (Ra 0.03-0.07 μm) and pressure application force (1.0-1.53 times the 0.2% proof stress). By controlling these parameters, the slide-contact surface achieves a consistent roughness (Ra 0.25-0.5 μm) that ensures both cost-effectiveness and manufacturing precision for wear resistance and oil film retainability
3Reliability
If the surface roughness is increased to improve oil film retainability, then oil film retainability is improved, but wear of the seal lip portion increases
Solution Approach 1:
The patent establishes an optimal parameter range for surface roughness (Ra 0.25-0.5 μm) that balances oil film retainability and wear prevention. This specific roughness range is achieved through controlled mold surface preparation and pressing parameters, ensuring that the surface is rough enough to retain oil film but not so rough as to cause excessive wear of the seal lip portion
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
The method allows for cost-effective and efficient production of rotary seals with reduced wear of seal lips while maintaining oil film retainability, by setting surface roughness within a specific range through controlled molding and burring processes.
Implementation Method 1
a ratio of pressure application force for holding the annular blank material between the faces to a 0.2% proof stress of the dull-finished material, is set to 1.0 or more and 1.53 or less
Implementation Method 2
the burring is performed using a mold having faces each of which has an arithmetical mean roughness Ra set to 0.03 μm≤Ra≤0.07 μm, the faces individually coming into contact with the first slide-contact surface and the second slide-contact surface
Data Source
AI summary
A manufacturing method of a slinger, includes steps of: molding an annular blank material from a dull-finished steel sheet material through sheet metal press working or the like; and burring the blank material to mold a slinger. The values of the arithmetical mean roughness Ra of faces, of a burring mold, which individually come into contact with first and second slide-contact surfaces of the slinger, are set to 0.03 μm≤Ra≤0.07 μm. A ratio of pressure application force for holding the blank material between the faces to the 0.2% proof stress of the dull-finished material, is set to 1.0 or more and 1.53 or less. A clearance for the burring mold is set to T×(0.9 to 0.7) where “T” represents the sheet thickness of the blank material.