Piston Pump Axial Guide Grooves Suction Efficiency
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Solution Overview
Problem
Existing piston pumps face challenges in suction efficiency due to perpendicular working fluid passages, leading to reliance on negative pressure, and have high production costs due to complex metal structures or low durability resin cylinders.
Innovation Solution
A piston pump design featuring a cylindrical piston with a large diameter piston portion including axial working fluid guide grooves and a metal-made pipe cylinder with a resin-molded outer cover, reducing suction resistance and manufacturing costs while enhancing durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the working fluid passage extends perpendicular to the piston moving direction, then the piston structure can be simplified, but the suction efficiency deteriorates because the reciprocating operation of the piston does not contribute to the suction
Solution Approach 1:
The working fluid passage is reoriented from a radial (perpendicular) direction to an axial direction that aligns with the piston's reciprocating motion. This dimensional change allows the piston's back-and-forth movement to directly drive the suction of working fluid through the passage, converting the piston's mechanical motion into effective fluid transport and resolving the contradiction between structural simplicity and suction efficiency.
2Reliability
If the cylinder is formed by cutting a metal-made member, then the durability is enhanced, but the production time and labor increase significantly
Solution Approach 1:
The cylinder material is changed from metal to resin, fundamentally altering the material parameter. This enables the cylinder to be manufactured through molding processes instead of cutting operations, dramatically reducing production time and labor while maintaining sufficient durability for the application.
Solution Approach 2:
The mechanical cutting process is replaced with a molding process. Instead of removing material through cutting to create the cylinder, the cylinder is formed by molding resin into the desired shape, eliminating the need for subsequent heat treatment and additional cutting operations to remove distortion.
3Ease of manufacture
If the cylinder is formed of resin molding, then the workability and production cost are reduced, but the durability to withstand repeated sliding movements deteriorates
Solution Approach 1:
The piston is constructed as a composite structure combining a metal cylindrical piston portion and a resin large diameter piston portion. The metal component provides durability for the sliding surface that contacts the cylinder, while the resin component enables easy manufacturing and cost reduction. This composite approach resolves the contradiction between ease of manufacture and durability.
Data Source
AI summary
According to one embodiment, there is provide a piston pump, including: a cylinder having a bottomed cylindrical shape; a piston slidable within the cylinder, the cylinder and the piston defining a pressure chamber therebetween; a suction valve unit disposed in a suction passage of the pressure chamber; and a discharge valve unit disposed in a discharge passage of the pressure chamber, wherein the piston includes a cylindrical piston portion and a large diameter piston portion provided to cover one end of the cylindrical piston portion, and wherein the large diameter piston portion includes a working fluid guide groove extending thereinside along the axial direction of the piston.