Cold-Formed Flat Top Plunger for Hydraulic Lash Adjuster

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Solution Overview

Problem

Hydraulic lash adjusters in internal combustion engines require complex subassemblies and extensive machining, leading to increased assembly time and resources, and existing plungers do not efficiently distribute force to minimize wear on engine components.

Innovation Solution

A cold-formed, one-piece external flat top plunger with integrated features like a shim and seal, which is manufactured to near net shape, reducing the need for extensive machining and incorporating a check valve assembly for fluid control, thereby simplifying assembly and reducing wear on engine components.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If traditional multi-component plungers are used, then assembly flexibility is maintained, but assembly time and resource consumption increase

Engineering Contradiction:
Improveassembly timeVSAvoidnumber of components
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent combines multiple separate components (plunger body, shim, and seal) into a single integrated cold-formed plunger component. This merging eliminates the need for separate assembly steps for these components, directly reducing assembly time and resource consumption while maintaining all necessary functional characteristics.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The cold-formed plunger is designed to perform multiple functions simultaneously: it provides structural support, acts as a shim for clearance adjustment, and incorporates sealing features. This multi-functionality consolidates what would traditionally require multiple specialized components into one universal part.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Manufacturing precision

If extensive machining is used to manufacture plungers, then manufacturing precision is achieved, but manufacturing costs and time increase

Engineering Contradiction:
Improveplunger dimensional accuracyVSAvoidmanufacturing cost
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The plunger components are cold-formed to near-net-shape dimensions before final assembly. This preliminary forming action achieves the majority of dimensional requirements through forming rather than subsequent machining, significantly reducing machining operations and associated costs while maintaining precision.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent replaces traditional hot-forming or extensive machining processes with cold-forming technology. This substitution enables near-net-shape manufacturing with reduced material waste, lower energy consumption, and decreased machining requirements, thereby reducing overall manufacturing costs.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Reliability

If conventional plunger designs are used, then structural simplicity is maintained, but force distribution and wear resistance are insufficient

Engineering Contradiction:
Improvewear resistanceVSAvoidplunger structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The cold-formed plunger incorporates locally optimized features including integrated shim areas with specific thickness variations and strategically positioned seal elements. These local quality enhancements improve force distribution across critical contact surfaces and enhance wear resistance without requiring a completely complex overall structure.

Inventive Principle:
Principle #3Local quality

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 solution reduces manufacturing costs and assembly time by minimizing the number of components and enhances wear resistance by evenly distributing force, improving the efficiency and longevity of hydraulic lash adjusters.

Implementation Method 1

evenly distributing force, improving the efficiency and longevity of hydraulic lash adjusters

Methodology Applied
Scientific EffectForce distribution: Pressure Gradient

Implementation Method 2

small quantities of hydraulic fluid are permitted to enter the pressure chamber, or escape therefrom, thus effecting an adjustment in the length of the lash adjuster

Methodology Applied
Scientific EffectHydraulic pressure control: Pressure Gradient

Data Source

PatentEP2386730B1Cold-Formed Flat Top Plunger for Use in a Hydraulic Lash Adjuster and Method of Making Same
Publication Date: 2018.09.19 EATON CORP
  • EP2386730B1 patent drawingFigure 1
  • EP2386730B1 patent drawingFigure 2~3
  • EP2386730B1 patent drawingFigure 4

AI summary

A cold-formed flat top plunger blank is provided for use in a hydraulic lash adjuster (100). An end wall (140) at the first end (134) of the plunger body (142) defines a flat top surface (180) that is cold-formed to final dimensions or net shape. The flat top surface (180) at the first end (134) of the plunger body (142) is configured to engage a flat surface within the mating bore of an engine cylinder head. By configuring the plunger body (142) to have a flat top surface (180) that engages a flat surface disposed within the mating bore of an engine cylinder head, the force applied to the engine block by the lash adjuster is distributed more evenly, minimizing wear. The external flat top plunger (116) is a unitary component cold-formed to near net shape, including cold-forming to final dimensions the flat top surface and a counterbore.