Spring Cover Attachment for Variable Valve Timing
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Solution Overview
Problem
Existing devices for changing the control times of gas exchange valves in internal combustion engines face challenges in simple and reliable assembly of the spring cover, which can detach under operating loads.
Innovation Solution
A form-fitting connection between the spring cover and the drive wheel, utilizing snap-in latching elements and anti-rotation pins, ensures secure attachment without requiring structural changes to the drive wheel or other components, allowing for a separate and straightforward assembly step.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the spring cover is attached using conventional fastening methods (bolts through multiple components), then the spring cover can be securely fixed, but the assembly process becomes complex and time-consuming
Solution Approach 1:
The attachment system is segmented into distinct functional elements: the spring cover with integrated latching hooks, the drive wheel with corresponding receptacles, and anti-rotation pins. This segmentation allows each component to perform its specific function independently, simplifying the overall assembly process while maintaining secure attachment.
Solution Approach 2:
The latching hooks are designed to automatically engage with the receptacles on the drive wheel when the spring cover is positioned correctly. This self-latching mechanism eliminates the need for complex fastening procedures or additional fastening steps, allowing the spring cover to secure itself to the drive wheel.
2Ease of manufacture
If the spring cover is made compact to minimize size, then material usage is reduced, but the spring cover may detach under operating loads
Solution Approach 1:
The spring cover exhibits local quality differentiation: the main body remains compact for manufacturing efficiency, while specific localized features (latching hooks and anti-rotation pins) are strategically positioned and dimensioned to provide enhanced retention. This allows the compact design to maintain both manufacturing simplicity and operational reliability.
Solution Approach 2:
The attachment mechanism combines multiple functional elements (latching hooks for primary retention, anti-rotation pins for rotational constraint) into a composite attachment system. This composite approach allows the compact spring cover to achieve reliable retention through the synergistic effect of different retention mechanisms rather than requiring a single oversized feature.
3Ease of operation
If the drive wheel position is shifted axially to create a fastening surface, then the spring cover can be attached, but structural changes to the drive wheel are required
Solution Approach 1:
The drive wheel is designed with multi-functionality: it serves both its primary function of transmitting rotational motion and provides integrated receptacles for the latching hooks. This eliminates the need for separate fastening surfaces or structural modifications, as the drive wheel's existing structure is utilized for both motion transmission and attachment purposes.
4Reliability
If additional fastening methods are introduced to prevent detachment, then retention reliability improves, but the device complexity and assembly steps increase
Solution Approach 1:
Multiple retention functions are merged into a single integrated attachment operation: the latching hooks engage with receptacles while anti-rotation pins simultaneously prevent rotational movement. This merging of retention and anti-rotation functions into one assembly step maintains high reliability without increasing assembly complexity or reducing productivity.
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
This solution provides a robust and reliable attachment of the spring cover, preventing detachment under operational loads and ensuring safe operation across varying temperatures, without the need for additional fastening methods or structural modifications.
Implementation Method 1
a torsion spring for rotating the rotor relative to the stator
Implementation Method 2
a torsion spring for rotating the rotor relative to the stator
Implementation Method 3
the vanes are displaced within the pressure chambers by supplying or discharging pressure medium from the pressure chambers
Implementation Method 4
fastening elements that correspond to one another are provided, which engage in one another and thus produce a particularly positive connection between the spring cover and the drive wheel
Data Source
Figure 1
Figure 2~3
Figure 4
AI summary
The invention relates to a device (1) for varying the control times of gas exchange valves of an internal combustion engine comprising a stator (3) and a rotor (5) accommodated therein. The rotor (5) can be connected to a camshaft and can be adjusted by a pressure means in the circumferential direction relative to the stator (3). The device (1) further comprises a front cover disc (7) and a rear cover disc (9), between which the stator (3) and the rotor (5) are accommodated. The rear cover disc (9) is provided with a drive wheel (11) that can be connected to a crankshaft. A spring (13) for rotating the rotor (5) relative to the stator (3) is arranged between the rear cover disc (9) and a spring cover (15), wherein the spring cover (15) is positively connected to the drive wheel (11), whereby simple installation of the spring cover (15) on the device (1) is made possible.