Variable Valve Drive Switching Rod Mechanism

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Solution Overview

Problem

Existing variable valve drives for combustion piston engines require complex and space-consuming arrangements of separate hydraulic or electromagnetic switching lines, making them difficult to implement in restricted cylinder head spaces, especially for selective control of multiple gas exchange valves.

Innovation Solution

A simplified actuating device using a single linear actuator and a switching rod with leaf springs, which is mechanically switchable and reduces installation space requirements, allowing for efficient switching of multiple finger followers and valve groups with a two-wire cable or single actuating pressure line, enabling reliable and quick actuation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If separate hydraulic or electromagnetic switching lines are used for each valve, then precise control of multiple gas exchange valves is achieved, but device complexity and installation space requirements increase significantly

Engineering Contradiction:

Improvecontrol capabilityVSAvoidswitching system complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

Multiple switching lines are merged into a single common switching line that serves all finger followers. The switching rod with integrated switching elements replaces multiple separate actuators, reducing system complexity while maintaining the ability to control multiple valves independently through the shared switching mechanism.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The common switching line and switching rod serve multiple functions by controlling multiple finger followers simultaneously. Each switching element on the rod can independently actuate different finger followers, allowing one component to perform the work of multiple separate actuators.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Adaptability or versatility

If separate hydraulic or electromagnetic switching lines are used for each valve, then precise control of multiple gas exchange valves is achieved, but installation space in the cylinder head increases

Engineering Contradiction:

Improvecontrol capabilityVSAvoidcylinder head space

Core Design Contradiction:

Adaptability or versatilityVSArea of stationary object

Solution Approach 1:

Multiple separate actuators are merged into a single compact switching rod assembly that accommodates all switching elements in a confined space. The common switching line replaces multiple parallel fluid lines, dramatically reducing the volume required in the cylinder head.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The switching elements are arranged along the switching rod in a nested or linear configuration, allowing multiple control functions to be packed into a compact arrangement that fits within the limited cylinder head space.

Inventive Principle:

Principle #7Nested doll (Nesting)

3Device complexity

If a mechanically switchable actuating device is used, then installation space and manufacturing complexity are reduced, but switching speed and reliability may be compromised

Engineering Contradiction:

Improvesystem simplicityVSAvoidswitching reliability

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The patent replaces complex hydraulic or electromagnetic systems with a purely mechanical switching mechanism. The switching rod with cam-actuated elements provides reliable, maintenance-free operation without the complexity of fluid systems or electrical components, while maintaining sufficient switching speed for engine operation.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

4Adaptability or versatility

If multiple separate actuators are used for each finger follower, then independent control is achieved, but manufacturing cost and assembly complexity increase

Engineering Contradiction:

Improveindependent valve controlVSAvoidmanufacturing simplicity

Core Design Contradiction:

Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

Multiple independent control functions are merged into a single modular switching rod assembly. This allows independent control of each finger follower while using a unified structure that is easier to manufacture and assemble than multiple separate actuators, reducing both production complexity and cost.

Inventive Principle:

Principle #5Merging (Combining)

Data Source

PatentUS10920625B2Variable valve drive of a combustion piston engine

Publication Date: 2021.02.16 SCHAEFFLER TECHNOLOGIES AG & CO KG

AI summary

The disclosure relates to a variable valve drive of a combustion piston engine with at least one gas exchange valve per cylinder, wherein each valve stroke is specified by a primary and secondary cam and transmitted to the gas exchange valve via a switchable cam follower that includes a primary lever and a secondary lever. The primary lever is in contact with the primary cam, and the secondary lever is in contact with the paired secondary cam and can be coupled to the primary lever by a coupling element. The coupling element includes a coupling pin, a locking pin, and an unlocking pin. Axially outer ends of the locking and unlocking pin protrude out of the secondary lever and are coupled to a shift rod via respective connection elements, the shift rod being longitudinally movable out of a rest position into a shift position by a linear actuator.