Internal Combustion Engine Valve Hardening via Radial Slip Forging

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Solution Overview

Problem

Existing methods for manufacturing valve faces for internal combustion engines fail to provide sufficient hardness and wear resistance, particularly for diesel engines using low-grade fuel, leading to issues with combustion residue deposition and blow-through characteristics.

Innovation Solution

A method involving a die unit with radial grooves and pressing protrusions, rotated relative to the intermediate valve product, to create radial slip deformations and uniformly harden the valve face, extending deep into the material, using a heat-resistant alloy and secondary forging to enhance both surface and deep-layer hardness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If a die with a circumferentially contiguous tapered pressing face is used to apply even pressure on the material surface, then the pressure distribution is uniform, but the hardening depth is limited and deep regions cannot be hardened

Engineering Contradiction:
Improvepressure distribution uniformityVSAvoidhardening depth
Core Design Contradiction:
Stability of the object's compositionVSLength of stationary object

Solution Approach 1:

The circumferentially contiguous tapered pressing face is divided into a plurality of radially extending pressing sections separated by grooves. This segmentation allows concentration of pressure on specific radial lines while maintaining overall uniformity through rotational forging, enabling deep hardening without sacrificing pressure distribution control.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Instead of uniform pressure distribution across the entire pressing face, the invention applies pressure locally at specific radial positions through discrete pressing sections. This creates concentrated stress zones that generate deep slip deformations and hardening at targeted locations, which then propagate uniformly through rotation.

Inventive Principle:
Principle #3Local quality

2Ease of manufacture

If conventional forging methods are used with limited pressure application, then the manufacturing process is simple, but the valve face hardness and wear resistance are insufficient

Engineering Contradiction:
Improveprocess simplicityVSAvoidvalve face hardness
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The die is segmented into multiple pressing sections that create radial slip deformations through concentrated pressure zones. This maintains manufacturing simplicity while achieving the required valve face hardness through enhanced plastic deformation mechanisms.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The intermediate valve product is rotated during forging to periodically bring different circumferential positions under the pressing sections. This periodic action ensures uniform hardening across the entire valve face while maintaining a relatively simple single-step forging process.

Inventive Principle:
Principle #19Periodic action

3Productivity

If the valve face is not sufficiently hardened, then the manufacturing process is less intensive, but combustion residues deposit and blow-through characteristics deteriorate

Engineering Contradiction:
Improvemanufacturing intensityVSAvoidcombustion residue deposition
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The segmented pressing sections create deep radial slip deformations that produce sufficient valve face hardness to resist combustion residue deposition and maintain blow-through characteristics, while avoiding excessive manufacturing intensity through efficient pressure concentration.

Inventive Principle:
Principle #1Segmentation

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 method effectively hardens the valve face, improving wear resistance and blow-through properties, enabling longer valve life and compliance with severe exhaust gas regulations by uniformly deforming the material across the valve face.

Implementation Method 1

plastically deforming a portion of the valve head of the intermediate valve product that corresponds to the tapered valve face such that an upward bulging portion is formed on that portion of the valve head

Methodology Applied
Scientific EffectPlastic deformation: Plasticity

Implementation Method 2

creating radial slip deformations in the valve face

Methodology Applied
Scientific EffectSlip deformation: Deformation

Implementation Method 3

by rotating an intermediate valve product through a predetermined angle, plastic deformation of the intermediate valve product is uniformized over the entire region to be forged

Methodology Applied
Scientific EffectRotation:

Data Source

PatentEP2767686B1Method for manufacturing valve for internal combustion engine
Publication Date: 2016.07.27 NITTAN VALVE CO LTD
  • EP2767686B1 patent drawingFigure 1
  • EP2767686B1 patent drawingFigure 2(a)~2(f)
  • EP2767686B1 patent drawingFigure 3(a)~3(c)

AI summary

OBJECT: To provide a method of manufacturing a valve for an internal combustion engine, the valve being highly hardened from the surface of its valve face to a deep region MEANS OF ACHIEVING THE OBJECT: A valve face (16) of an intermediate valve product W3 is forged, utilizing a die unit (40) equipped with a die (42) having protruding pressing sections and with a press punch (48), so as to create radial slip deformations therein The die (42) also has grooves (46) formed along the circumference of the die such that the grooves (46) and the pressing sections alternate. During forging, the intermediate valve product W3 is repeatedly rotated through a predetermined angle relative to the die (40) in synchronism with the punch (48) in operation. By virtue of the protruding pressing section (43), the die (42) can provide the valve head with larger plastic deformations in a deeper region than conventional dies, thereby hardening the deeper layers as well as shallow layers of the valve face. Although deformations of the valve face (16) deformed once by the protruding pressing sections 43 are discontinuoously distributed along the periphery of the valve head, the valve face 16 becomes uniformly deformed after it is repeatedly rotated relative to the pressing protrusions 43 during forging.