Hydraulic Pump Piston-Shoe Assembly Using Plug Retention

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Solution Overview

Problem

The crimped portions of the shoe in existing piston and shoe assemblies in hydraulic pumps are prone to failure, leading to potential weakness and reduced durability.

Innovation Solution

A method of assembling and disassembling the piston and shoe without crimping, involving the insertion of the piston shaft through the shoe aperture, use of a plug to secure the piston head, and optional installation of a piston sleeve, allowing for secure assembly and disassembly without deformation of the shoe.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the piston sphere is crimped into the shoe socket, then the piston is secured to the shoe, but the crimped portions of the shoe become weak points that can fail in use

Engineering Contradiction:

Improvedurability of piston-shoe assemblyVSAvoidstrength of crimped portions

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

The invention extracts the crimping operation from the assembly process and replaces it with a shaft-through-aperture mechanism. The piston shaft passes through an aperture in the shoe and is secured by a retaining ring or clamp, eliminating the need for crimping the shoe material itself and thus removing the weak points that would otherwise exist.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The invention introduces an intermediary element (retaining ring or clamp) between the piston shaft and the shoe aperture. This intermediary component provides the securing function without requiring deformation of the shoe material, thereby maintaining the strength and integrity of the shoe while still achieving secure attachment.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Strength

If the piston shaft is inserted through the shoe aperture, then the assembly strength is improved, but the assembly process becomes more complex

Engineering Contradiction:

Improvestrength of piston-shoe assemblyVSAvoidcomplexity of assembly process

Core Design Contradiction:

StrengthVSDevice complexity

Solution Approach 1:

The invention segments the securing function into separate components: the piston shaft with its aperture, the retaining ring or clamp, and the shoe. This segmentation allows each component to be optimized independently and simplifies the assembly process, as the retaining ring or clamp can be easily installed around the shaft after it passes through the shoe aperture.

Inventive Principle:

Principle #1Segmentation

Data Source

PatentUS20250347276A1Piston assembly for hydraulic pump

Publication Date: 2025.11.13 GOODRICH ACTUATION SYST

AI summary

A method of assembling a piston and shoe of a hydraulic pump. The method includes: inserting a shaft of the piston through an aperture of the shoe such that it extends through to the other side until a piston head of the piston is seated in the shoe. A piston and shoe assembly for a hydraulic pump. The assembly includes: a piston comprising a piston shaft and a piston head; and a shoe comprising an aperture, wherein the piston shaft is sized such that it can pass through the shoe aperture and the piston head is sized such that it cannot pass through the shoe aperture.