Switchable Rocker Arm Layout for Compact Variable Valve Actuation

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Solution Overview

Problem

Packaging switchable rocker arms in the tight spaces of combustion machines is problematic, and there is a desire for lightweight designs with integrated manufacturing for easy installation.

Innovation Solution

A switchable rocker arm design featuring a main body with a cam end and valve end, a second body with pivot and latch bores, a latch assembly, and a lost motion spring mounted over a transfer portion, along with a hydraulic feed to control pistons and latches, allowing for variable valve actuation techniques.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If switchable rocker arm components are added to enable variable valve actuation, then valve actuation versatility is improved, but packaging space requirements increase

Engineering Contradiction:

Improvevariable valve actuationVSAvoidpackaging space

Core Design Contradiction:

Adaptability or versatilityVSVolume of moving object

Solution Approach 1:

The latch assembly is nested within the transfer portion of the second body, with the latch bore positioned to allow the latch to engage with the piston assembly while remaining compactly integrated into the existing rocker arm structure. This nesting approach enables variable valve actuation functionality without proportionally increasing the overall packaging volume.

Inventive Principle:

Principle #7Nested doll (Nesting)

Solution Approach 2:

The design utilizes three-dimensional spatial arrangement by positioning the latch assembly in a vertical orientation within the transfer portion, and by forking the cam end to create separate arm borders that accommodate piston bores in different spatial planes. This dimensional optimization allows multiple functional elements to coexist within the tight space constraints of the combustion machine.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Ease of manufacture

If multiple separate components are used for switchable functionality, then ease of manufacture is improved, but device complexity increases

Engineering Contradiction:

Improvecomponent fabricationVSAvoidassembly structure

Core Design Contradiction:

Ease of manufactureVSDevice complexity

Solution Approach 1:

The rocker arm is divided into distinct functional segments: a main body for rotation, a second body containing the latch assembly, and separate piston assemblies for each arm border. This segmentation allows each component to be manufactured independently using optimized processes while maintaining clear functional boundaries that simplify the overall assembly process despite the increased number of parts.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The transfer portion serves multiple functions: it acts as a structural connector between the main body and second body, provides a mounting location for the latch assembly, and incorporates the bearing axle for rotation. This multi-functionality reduces the need for additional separate components, thereby managing device complexity while maintaining ease of manufacture.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Device complexity

If traditional rocker arm design is used, then structural simplicity is maintained, but variable valve actuation capability is lost

Engineering Contradiction:

Improvestructural simplicityVSAvoidvariable valve actuation

Core Design Contradiction:

Device complexityVSAdaptability or versatility

Solution Approach 1:

The design transforms the traditional static rocker arm into a dynamic system capable of multiple operational states. The latch assembly can engage or disengage from the piston assembly, and the second body can pivot relative to the main body, enabling the system to adapt between different valve actuation modes (e.g., cylinder deactivation, early/late valve opening) while maintaining a fundamentally simple rocker arm structure.

Inventive Principle:

Principle #15Dynamics

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

Enables efficient packaging and lightweight integration of switchable rocker arms, facilitating easy installation and effective variable valve actuation, including cylinder deactivation and other techniques.

Implementation Method 1

A lost motion spring can be mounted over the transfer portion

Methodology Applied

Scientific EffectElasticity: Elasticity

Implementation Method 2

A hydraulic feed in the main body can be configured to supply hydraulic fluid to the first piston bore and to the second piston bore

Methodology Applied

Scientific EffectHydraulic pressure: Hydraulic Press

Data Source

PatentUS20250382904A1Switchable rocker arm

Publication Date: 2025.12.18 EATON INTELLIGENT POWER LTD

AI summary

A switchable rocker arm can comprise a main body configured to rotate around a rocker shaft. The main body can comprise a valve end and a cam end. A second body can comprise a cam-receiving transfer portion and a latch bore through the transfer portion. The cam-receiving transfer portion can include a bearing axle and a roller bearing. A latch assembly including a first latch and a second latch can be mounted in the latch bore.