Double-Hub Pulley Decoupler for Common Crankshaft Screws
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Solution Overview
Problem
Existing pulley decouplers for motor vehicle drive trains face challenges in using common crankshaft screws across different drive trains due to design constraints, leading to increased costs and potential incompatibility.
Innovation Solution
A pulley decoupler design featuring a multipart pulley hub with a first hub surrounding the crankshaft and a second hub with a mounting pin, allowing the arc spring flange and torsional vibration damper flange to be non-rotatably mounted on the pulley hub's lateral surface, enabling the use of common crankshaft screws by adjusting the contact surface for screw heads and utilizing an interference fit for secure connection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a serial construction with multiple components (hub, arc spring flange, torsional vibration damper flange) is used, then the structural integrity and functionality are ensured, but the contact surface distance from the crankshaft increases, making common crankshaft screws unusable
Solution Approach 1:
The patent applies nesting by placing the second hub inside the first hub, with the mounting pin extending through both hubs. This nested configuration allows the contact surface for screw heads to be positioned closer to the crankshaft while maintaining all necessary functional components, enabling the use of common crankshaft screws across different drive trains.
2Ease of manufacture
If the contact surface for screw heads is positioned far from the crankshaft due to component widths, then sufficient space for all components is provided, but the minimum distance requirement prevents use of common crankshaft screws
Solution Approach 1:
The patent resolves the spatial conflict by transitioning from a linear axial arrangement to a nested concentric arrangement. The second hub is positioned inside the first hub, utilizing the radial dimension to create the contact surface closer to the crankshaft without reducing the axial space available for other components.
3Adaptability or versatility
If a multipart hub design is used to adapt to different drive trains, then versatility and compatibility are improved, but the device complexity increases
Solution Approach 1:
The multipart hub design achieves universality by enabling the same pulley decoupler to accommodate different crankshaft screw configurations across various drive trains. The first and second hubs work together to provide both structural support and adjustable mounting positions, making the assembly compatible with multiple drive train designs without requiring complete redesign.
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 design allows for the use of common crankshaft screws across different drive trains, simplifies mounting, and increases torque transmission capacity while maintaining friction coefficient and clamping force, thus reducing costs and improving adaptability.
Implementation Method 1
The mounting process for mounting the pulley decoupler on the crankshaft is thereby simplified. It has proven particularly advantageous for this purpose if there is an interference fit/press fit between the first hub and the second hub.
Implementation Method 2
It is advantageous here if the mounting pin is designed as a hollow bolt. A hollow bolt has the necessary stability and is lighter than a solid bolt, thereby making it possible to save weight.
Implementation Method 3
The arc spring flange and the torsional vibration damper flange are pre-mounted on the second hub with the aid of the mounting pin. The flanges are thereby already radially pre-positioned but still capable of (free) axial movement. The axial movement is restricted only by the second hub.
Data Source
AI summary
A pulley decoupler for a drive train of a motor vehicle is disclosed for eliminating or reducing rotation-related irregularities transmitted by a crankshaft. The pulley decoupler comprises a pulley hub, an arc spring flange, and a torsional vibration damper flange of a torsional vibration damper. In embodiments, the pulley hub, the arc spring flange, and the torsional vibration damper flange are configured to be non-rotatably mounted on a crankshaft by at least one crankshaft screw. The pulley hub has an outer lateral surface region on which both the torsional vibration damper flange and the arc spring flange are received and on which they are configured to be non-rotatably mounted.