Fuel Supply Pump Tappet Support Member Distortion Control
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Solution Overview
Problem
The existing fuel supply pumps face issues with distortion of slide surfaces due to press-fitting of tappet support members, requiring reprocessing, and lack effective support for the tappet, leading to weight reduction challenges and limited rotation of the shoe.
Innovation Solution
A fuel supply pump design featuring a tappet support member with planar slide surfaces and press-fitting projections that minimize distortion and wobbling, using a cylindrical roller and rectangular shoe configuration, supported by metal plates with slide and press-fitting surfaces to enable axial reciprocation and rotation, and made from ferrous materials for enhanced strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If the tappet support member is press-fitted into the pump housing to reduce tappet weight and limit shoe rotation, then the tappet weight is reduced and shoe rotation is limited, but the slide surfaces of the slide hole become distorted
Solution Approach 1:
The slide hole is divided into two functional parts: a quadrangular prism-shaped portion that limits shoe rotation, and a cylindrical portion that provides a distortion-free sliding surface. This segmentation allows each part to fulfill its specific function without interfering with the other.
Solution Approach 2:
The cylindrical portion of the slide hole acts as an intermediary between the press-fitted tappet support member and the shoe. It provides a stable, distortion-free sliding surface that mediates the interaction between the shoe and the pump housing, ensuring smooth reciprocating motion despite the press-fitting distortion.
2Manufacturing precision
If the slide hole is reprocessed after press-fitting to correct distortion, then the slide surface precision is improved, but the manufacturing time and complexity increase
Solution Approach 1:
The slide hole is designed with a cylindrical portion that is inherently resistant to distortion from press-fitting. This preliminary design consideration eliminates the need for post-press-fitting reprocessing, as the cylindrical geometry naturally compensates for the distortion caused by the press-fitted tappet support member.
3Stability of the object's composition
If the shoe is configured as a quadrangular prism to limit rotation, then rotation control is achieved, but the slide surfaces are prone to distortion during press-fitting
Solution Approach 1:
The slide hole is segmented into a quadrangular prism-shaped portion that contacts the shoe to limit rotation, and a cylindrical portion that provides a distortion-free sliding surface. This segmentation allows the shoe to maintain its quadrangular prism shape for rotation control while the cylindrical portion accommodates press-fitting without distortion.
Data Source
AI summary
A tappet support member includes at least two slide surfaces and at least two press-fitting projections. The at least two slide surfaces, are planar and extend in an axial direction of a plunger. The at least two slide surfaces are substantially parallel to each other and are opposed to each other, and a shoe of a tappet is axially reciprocatably supported by the at least two slide surfaces. Each of the at least two press-fitting projections projects from a corresponding side of the tappet support member that is opposite from a corresponding one of the at least two slide surfaces, and each of the at least two press-fitting projections is press-fitted into a pump housing, which is stationary relative to the tappet.