Brake Guide Ring Geometry for Low-Resistance Piston Sliding
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Solution Overview
Problem
The existing brake hydraulic pressure control apparatus faces issues with increased processing costs and sliding resistance due to the need for strict dimensional tolerance and accurate coaxiality between the guide member and the cylinder hole, leading to potential surface treatment peeling and deformation during press-fitting.
Innovation Solution
A brake hydraulic pressure control apparatus with a guide ring that includes a flange portion and bulged portions with tapered sections, allowing for adjustable coaxiality and reduced sliding resistance, thereby alleviating the issues of surface treatment peeling and deformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the guide member is press-fitted to the cylinder hole with a large fastening allowance, then the ease of manufacture is improved, but the sliding resistance increases causing surface treatment peeling or inner diameter deformation
Solution Approach 1:
The guide member is divided into two functional parts: the guide portion (inner diameter portion) and the fastening portion (outer diameter portion). This segmentation allows each part to be optimized independently - the guide portion can have tight tolerance for low sliding resistance, while the fastening portion can have loose tolerance for easy manufacture.
Solution Approach 2:
Different dimensional tolerances are applied to different parts of the guide member. The inner diameter portion (guide surface) has strict tolerance control to minimize sliding resistance, while the outer diameter portion (fastening surface) has relaxed tolerance to reduce manufacturing cost. This local quality differentiation resolves the contradiction between precision and ease of manufacture.
2Device complexity
If the guide member is integrally formed with the base body, then the device complexity is reduced, but the processing cost increases due to requiring separate processing facilities
Solution Approach 1:
The guide member is designed as a separate component from the base body, allowing it to be manufactured using standard turning facilities rather than requiring specialized processing equipment for integral formation. This segmentation reduces processing cost while maintaining structural simplicity.
Solution Approach 2:
The guide member integrates multiple functions into a single component: guiding the piston, providing surface treatment for low friction, and enabling fastening to the base body. This functional merging maintains device simplicity while the separate manufacturing approach reduces processing cost.
3Reliability
If strict dimensional tolerance is applied to the guide member, then the sliding resistance is reduced, but the processing cost is increased
Solution Approach 1:
Strict dimensional tolerance is applied only to the inner diameter portion (guide surface) where low sliding resistance is critical, while the outer diameter portion (fastening surface) uses relaxed tolerance. This localized precision approach reduces overall processing cost while maintaining reliability where needed.
Solution Approach 2:
The guide member is segmented into the guide portion requiring high precision and the fastening portion requiring low precision. This allows differential tolerance specification, reducing manufacturing cost by applying strict tolerance only where necessary for performance.
Data Source
AI summary
To prevent occurrence of contamination at the time of press-inserting and fixing a guide ring that guides sliding of a piston.In a brake hydraulic pressure control apparatus (1) including: a base body (2) having a cylinder hole (3); a piston (5) fitted to the cylinder hole (3) in a freely slidable manner; and a guide ring (8) attached to an opening (9) of the cylinder hole (3) and guiding sliding of the piston (5), the guide ring (8) has: a flange portion (8e) in a lower surface (8b) opposing the cylinder hole (3), the flange portion (8e) expanding in a radial direction of the guide ring (8); and bulged portions (8c) arranged at equally-spaced intervals to an outer circumferential surface (8d) of the guide ring (8) and each bulged outward in the radial direction of the guide ring (8) when compared to the flange portion (8e). When seen from a cross section in an axial direction (Ax) of the guide ring (8), each of the bulged portions (8c) has a tapered portion (8f) expanding in the radial direction of the guide ring (8) from the lower surface (8b) toward an upper surface (8a) of the guide ring (8).