Plastic Stator Valve Timing Control with Embedded Metal Inserts

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Solution Overview

Problem

Existing valve timing control systems for internal combustion engines face challenges in reducing cost and weight while maintaining durability against mechanical and thermal stresses, as conventional metal components are costly and heavy, and previous attempts with low-cost plastics have been unsuccessful due to inability to withstand impacts and elevated temperatures.

Innovation Solution

A valve timing control system with a stator body made of low-cost plastic and embedded threaded metal inserts, which secures a metal sprocket and protects the plastic stator body from mechanical impacts and thermal distortion, using a one-piece molded plastic construction for the stator body and annular side wall with metal inserts to maintain structural integrity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If metal materials are used for the stator body and rotor, then the valve timing control can withstand mechanical impacts and thermal stresses, but the cost and weight of the valve timing control increase

Engineering Contradiction:

Improvewithstand mechanical impacts and thermal stressesVSAvoidweight of valve timing control

Core Design Contradiction:

ReliabilityVSWeight of moving object

Solution Approach 1:

The patent employs a composite construction where the stator body is made of plastic material while metal inserts are embedded within it. This composite approach allows the plastic stator body to provide lightweight structure while the metal inserts reinforce specific areas to withstand mechanical impacts and thermal stresses, thereby resolving the contradiction between reliability and weight.

Inventive Principle:

Principle #40Composite materials

2Ease of manufacture

If low-cost plastic material is used for the stator housing, then cost and weight are reduced, but the material cannot withstand mechanical impacts and elevated temperatures

Engineering Contradiction:

Improvecost and weight reductionVSAvoidwithstand mechanical impacts and elevated temperatures

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The patent uses a composite structure combining plastic stator body with embedded metal inserts. The plastic material provides cost-effectiveness and weight reduction, while the metal inserts are strategically positioned to reinforce areas subjected to mechanical impacts and thermal stresses, thus maintaining reliability while achieving cost and weight benefits.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent applies local reinforcement by embedding metal inserts only in specific critical areas of the plastic stator body where mechanical impacts and thermal stresses are most severe, rather than making the entire stator body from metal. This localized approach maintains overall cost-effectiveness while providing targeted strength where needed.

Inventive Principle:

Principle #3Local quality

3Ease of operation

If the rotor freely rotates relative to the stator body during engine startup, then the valve timing control is not pressurized with hydraulic fluid, but the rotor mechanically impacts the stator body

Engineering Contradiction:

Improveunpressurized operation during startupVSAvoidmechanical impact on stator body

Core Design Contradiction:

Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The patent incorporates metal inserts embedded in the plastic stator body that serve as protective elements before hydraulic pressure is applied. These metal inserts are positioned to absorb and withstand mechanical impacts from the rotor during engine startup when the system is unpressurized, preventing damage to the plastic stator body structure.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

Solution Approach 2:

The composite construction of plastic stator body with embedded metal inserts provides the necessary impact resistance during unpressurized startup operation. The metal inserts specifically handle the mechanical impact loads while the plastic body maintains the overall structure, enabling the system to operate without hydraulic pressure during startup without suffering damage.

Inventive Principle:

Principle #40Composite materials

Data Source

PatentUS9494060B2Valve timing control

Publication Date: 2016.11.15 HITACHI AUTOMOTIVE SYSTEMS AMERICAS INC

AI summary

A valve timing control having a stator body constructed of a plastic material. The stator body has an annular side wall and a front plate which, together, define a plurality of annularly spaced internal cavities within the stator body. A rotor having a plurality of vanes is positioned within the stator body so that one vane is positioned within each cavity. The rotor is movable relative to the stator body between a first and second rotational position. A plurality of threaded metal inserts are embedded within the stator body and used to attach a metal sprocket to the stator body at a position opposed to the front plate. Two of these inserts also receive the impact load from the rotor.