High-Pressure Fuel Pump Cylinder Bonding via Protrusion
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Solution Overview
Problem
Existing high-pressure fuel supply pumps face challenges in maintaining sealability and compactness due to the use of high-strength materials, leading to increased manufacturing costs and potential mechanical failures, especially when dealing with high fuel pressures.
Innovation Solution
A high-pressure fuel supply pump design featuring a cylindrical pump body with a protrusion on the opposite side of the pressurizing chamber, which supports the cylinder and enhances sealability through plastic bonding, preventing material deformation and mechanical stress concentration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If high strength materials are used to cope with high fuel pressure, then the deformation resistance is improved, but the manufacturing cost increases and the pump body size increases
Solution Approach 1:
The invention applies local quality by using high strength materials only in critical areas (cylinder and plug) that require high deformation resistance, while the pump body can use lower cost materials. The convex portion provides localized structural reinforcement without requiring the entire pump body to be made of high strength material, thus resolving the contradiction between strength and manufacturing cost.
2Force
If the cylinder end surface is brought into close contact with the pump body by screw axial force, then the fixing is achieved, but fine gaps may remain and sealability is not maintained
Solution Approach 1:
The invention applies preliminary action by pre-forming a convex portion on the pump body end surface before assembly. This convex portion makes initial contact with the cylinder end surface, establishing the sealing interface in advance. When the screw is tightened, the force is applied to this pre-positioned convex portion rather than relying on surface roughness or geometric tolerance to achieve contact, ensuring reliable sealability from the beginning of the tightening process.
3Volume of moving object
If caulking coupling is used to make the fixing compact, then the pump body size is reduced, but the punch may be easily broken and the caulked portion may lead to cracking
Solution Approach 1:
The invention applies inversion by reversing the traditional caulking approach. Instead of using a punch to force material flow (which concentrates stress and causes failure), the convex portion of the pump body itself makes contact with the cylinder end surface. The sealing force is generated by the screw tightening the cylinder to the pump body, with the convex portion serving as the contact point. This eliminates the need for a separate punch tool and avoids the stress concentration and material flow issues that lead to cracking and mechanical failure.
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 design achieves excellent sealability and compactness, reducing manufacturing costs and preventing mechanical failures, even with high-strength materials, by plastic bonding the cylinder and pump body without causing cracks or breakage.
Implementation Method 1
the convex portion is pressurized in an axial direction of the cylinder by a punch, and the convex portion is plastically deformed toward an inner peripheral side of the cylinder hole
Data Source
AI summary
Provided is a high-pressure fuel supply pump capable of fixing a cylinder to a pump body with excellent sealability in a simple structure even at a high fuel pressure.A high-pressure fuel supply pump including a pump body in which a pressurizing chamber is formed, and a cylinder inserted into a hole formed in the pump body and formed in a cylindrical shape, the high-pressure fuel supply pump including: a protrusion disposed at an end portion of the pump body opposite to the pressurizing chamber, formed from an outer peripheral side to an inner peripheral side with respect to an inner peripheral surface opposite to an outer peripheral surface of the cylinder, and protruding toward the cylinder, wherein the protrusion is formed so as to protrude to a side opposite to the pressurizing chamber with respect to a flat portion of the end portion of the pump body, and the protrusion is formed so as to support the cylinder from a side opposite to the pressurizing chamber.