Variable Valve Device Lubrication Passage Design

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Solution Overview

Problem

Existing variable valve devices face challenges in appropriately supplying lubrication oil to multiple components, leading to reduced durability due to complex lubrication passages and increased components to be lubricated.

Innovation Solution

A variable valve device design that includes a pair of cam housings, a camshaft, rocker shafts, and rocker arms, with a switching mechanism for coupling and separating intake arms. The device features an upper housing with specific injection holes for lubrication oil, where the passage length from a lubrication groove around the camshaft to a second injection hole is longer than to a first injection hole, increasing oil pressure for effective lubrication.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the number of components to be lubricated is increased to enable switching mechanism and multiple rocker arms, then the valve operation switching capability is improved, but the lubrication passage becomes complicated and lubrication supply becomes insufficient

Engineering Contradiction:

Improvevalve operation switching capabilityVSAvoidlubrication passage complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The lubrication system is segmented into multiple independent lubrication passages, each dedicated to supplying lubrication oil to specific components (switching mechanism, intake rocker arms, exhaust rocker arms). This segmentation allows each passage to be optimized for its specific target, preventing the complexity that would arise from a single complicated passage while ensuring adequate lubrication supply to all components.

Inventive Principle:

Principle #1Segmentation

2Adaptability or versatility

Engineering Contradiction:

Improvevalve operation switching capabilityVSAvoidlubrication supply adequacy

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The lubrication system is divided into separate passages for different component groups, ensuring that each component receives adequate lubrication oil supply regardless of the increased number of components. This segmentation maintains reliability by preventing lubrication deficiency that would occur in a shared complicated passage system.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Each lubrication passage is designed with specific local characteristics (passage length, diameter, routing) optimized for its target components. For example, passages supplying the switching mechanism have different dimensions compared to those supplying rocker arms, ensuring appropriate lubrication oil flow and pressure for each specific lubrication point.

Inventive Principle:

Principle #3Local quality

3Reliability

If multiple injection holes are provided for different components, then the lubrication coverage is improved, but the device complexity increases

Engineering Contradiction:

Improvelubrication coverageVSAvoidhousing structure complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The upper housing serves multiple functions: it supports the camshaft, accommodates the switching mechanism, provides mounting for rocker shafts, and contains the lubrication passages with injection holes. By making the housing multi-functional, the patent avoids the need for separate structures for each function, thereby reducing overall device complexity while maintaining comprehensive lubrication coverage.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 design ensures appropriate lubrication for both the switching mechanism and rocker arms, even with an increased number of components, thereby enhancing durability and lubricity.

Implementation Method 1

the lubrication oil is pressure-fed from a lubrication groove around the camshaft to the first injection hole and the second injection hole

Methodology Applied

Scientific EffectPressure gradient: Pressure Gradient

Data Source

PatentUS12331668B1Variable valve device

Publication Date: 2025.06.17 SUZUKI MOTOR CORP

AI summary

A variable valve device includes a pair of cam housings separated from each other in a predetermined direction, a pair of rocker shafts supported by the pair of cam housings, a plurality of rocker arms supported by the pair of rocker shafts in a swingable manner, a switching mechanism that couples and separates intake arms, and an upper housing on the pair of cam housings. The upper housing is formed with a first injection hole for supplying lubrication oil to the switching mechanism and a second injection hole for supplying lubrication oil to the rocker arms. A passage length from a lubrication groove around a camshaft to the second injection hole is larger than a passage length from the lubrication groove to the first injection hole.