Valve Timing Control Device Positioning Pin Design

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Solution Overview

Problem

Conventional valve timing control devices require precise manufacturing of positioning pins and press-fitting, leading to increased costs due to the need for precise hole manufacturing and labor-intensive processes.

Innovation Solution

A valve timing control device design featuring a casing with inward protruding shoes forming hydraulic chambers, a rotor with vanes, a camshaft fitting recess, and a positioning pin with an outer circumference engagement groove, where the pin is inserted into a step portion of the camshaft fitting recess and sealed by a housing to prevent falling out, eliminating the need for press-fitting and allowing for cost-effective assembly.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a positioning pin is press fitted and fixed on the camshaft side or rotor side, then the rotor and camshaft can be positioned in the circumference direction, but the manufacturing precision requirement increases and press-fitting man hours are required, so the cost increases

Engineering Contradiction:

Improvepositioning reliabilityVSAvoidmanufacturing cost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The positioning pin is divided into two functional segments: a first portion inserted into the pin insertion hole for positioning, and a second portion extending to engage with the pin engagement groove on the camshaft. This segmentation allows the pin to perform positioning and engagement functions without requiring press-fitting, as the groove engagement provides the necessary retention.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The pin engagement groove on the camshaft acts as an intermediary element that receives and secures the positioning pin. Instead of directly press-fitting the pin into the camshaft or rotor, the groove serves as a mediating structure that provides both positioning and retention functions, eliminating the need for high-precision hole manufacturing and press-fitting operations.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If a positioning pin is used to position the rotor and camshaft, then the positioning function is achieved, but the pin may fall out during assembly, requiring additional retention mechanisms

Engineering Contradiction:

Improvepositioning functionVSAvoidassembly complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The positioning and retention functions are merged into a single integrated structure. The positioning pin combines the positioning portion (inserted into the pin insertion hole) and the engagement portion (extending to engage with the pin engagement groove) into one unified component, eliminating the need for separate retention mechanisms and simplifying the assembly process.

Inventive Principle:

Principle #5Merging (Combining)

Data Source

PatentUS9540965B2Valve timing control device and method of assembly thereof

Publication Date: 2017.01.10 MITSUBISHI ELECTRIC MOBILITY CORP

AI summary

A positioning pin 31 is inserted in a pin insertion hole 30 penetrating through a rotor 3 in an axial direction, and has both end portions held by a housing 1 and a cover 12 to prevent falling out thereof. A protrusion 31a of the positioning pin 31 protruding toward an inner side of a camshaft fitting recess 3g is engaged with a pin engagement groove 110 recessed on an outer circumference surface of an intake side camshaft 100, whereby the rotor 3 and the intake side camshaft 100 are positioned in a rotation direction.