Valve Drive Device Axial Length Reduction
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Solution Overview
Problem
Existing valve drive devices for internal combustion engines are not compact or cost-effective, leading to high construction lengths and minimum valve spacings, which limits their application in small engines and increases production and repair costs.
Innovation Solution
A valve drive device with a cam unit having multiple cam tracks and a displacement body that can shift in two actuation directions, allowing for compact construction and low axial length, achieved through a support element fixed to the housing and a switching unit with angled contact surfaces and displacement contours, enabling efficient actuation of multiple valves with minimal spacing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If a conventional valve drive device is used, then the valve can be actuated, but the axial construction length is large and the device is not compact
Solution Approach 1:
The displacement body utilizes angled contact surfaces (e.g., 45 degrees) to convert axial actuation force into radial displacement of the cam unit. This dimensional transformation allows the cam unit to shift axially on the cam shaft without requiring a long axial construction, achieving compact design while maintaining actuation capability
Solution Approach 2:
The cam unit is segmented into multiple independent cam elements (first cam element, second cam element) that can be axially shifted relative to each other on the cam shaft. Each cam element has its own cam track configuration, allowing independent selection of valve actuation characteristics. This segmentation enables compact axial design while providing versatile valve control
2Volume of moving object
If the axial construction length is reduced for compact design, then the device becomes more compact, but the valve spacing must be minimized which limits application in small engines
Solution Approach 1:
By converting axial motion to radial displacement through angled contact surfaces, the invention minimizes the axial space required between valves. This allows the valve drive device to achieve compact radial volume while maintaining sufficient axial clearance for proper valve spacing, enabling application in both small and large engines
Solution Approach 2:
The displacement body with angled contact surfaces and the multi-cam element configuration provide universal applicability across different engine types. The same basic structure can be adapted to various valve spacing requirements and engine sizes by adjusting the cam track profiles and shifting positions, not limited to small engines only
3Ease of manufacture
If a simple construction is used, then production and repair costs are reduced, but the valve drive device cannot achieve compact dimensions
Solution Approach 1:
The displacement body integrates multiple functions into a single component: it acts as both the actuation interface and the displacement mechanism for the cam unit. The angled contact surfaces are formed directly on the displacement body, eliminating the need for separate levers or linkages. This merging achieves compact axial length while maintaining simple construction suitable for cost-effective manufacturing and repair
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 solution results in a compact, cost-effective valve drive device with low axial construction length, allowing for efficient actuation of multiple valves with minimal spacing, enabling application in small engines and reducing production and repair costs.
Implementation Method 1
a displacement body (18), which is provided for displacing at least one part of the cam unit (13) in the direction of a first actuation direction (32) for axial shifting
Data Source
AI summary
A valve drive device, in particular for an internal combustion engine, includes a support element fixed to a housing and at least one axially shiftable cam unit allocated to a valve. The cam unit has at least three cam tracks. At least one switching unit which is a displacement body is provided to displace at least one part of the cam unit in the direction of a first actuation direction for axial shifting. The displacement body displaces at least one part of the cam unit in the direction of a second actuation direction opposing the first actuation direction.