Eccentric Tensioning Device with Self-Release Fixing Mechanism
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Solution Overview
Problem
Conventional eccentric tensioning devices for traction means in internal combustion engines face challenges in ensuring consistent pretensioning and easy installation, particularly in addressing assembly-specific tolerances and dynamic behavior effects.
Innovation Solution
An eccentric tensioning device with a track roller, work eccentric, torsion spring, and fixing device that allows for pretensioning and automatic release during mounting, utilizing a helical spring and damping or braking mechanisms to maintain constant tension and prevent relocking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the work eccentric is fixed in the mounting position using a fixing device, then the pretensioning state is maintained during assembly, but the installation complexity increases due to the additional fixing and release mechanisms
Solution Approach 1:
The work eccentric is preliminarily fixed in the mounting position by the fixing device before the attachment screw is tightened. This preliminary action ensures that the correct pretensioning state is established and maintained during the assembly process, preventing any drift in the eccentric position that would compromise pretensioning consistency.
Solution Approach 2:
The fixing device is designed to automatically detach itself when the attachment screw is tightened and the axial play is overcome. This self-service mechanism eliminates the need for manual intervention to release the fixing device, reducing installation complexity while maintaining reliability. The device serves itself by using the assembly process forces to trigger its own release.
2Ease of manufacture
If the work eccentric is allowed to move during mounting, then the installation process is simpler, but the pretensioning force becomes inconsistent due to assembly tolerances
Solution Approach 1:
The fixing device performs a preliminary action by securing the work eccentric in the correct mounting position before the final assembly is completed. This ensures that even though the eccentric can move during mounting (ease of manufacture), it is held in the precise position needed for consistent pretensioning once the attachment screw is tightened.
Solution Approach 2:
The fixing device acts as an intermediary mechanism between the work eccentric and the mounting process. It mediates between the need for movement during assembly and the need for precision in the final position, allowing the eccentric to be easily installed while ensuring it reaches and stays in the correct position for consistent pretensioning.
3Stability of the object's composition
If the torsion spring is continuously pretensioned, then the traction means is consistently tensioned, but the risk of inadvertent relocking increases during operation
Solution Approach 1:
The engagement structure is extracted or separated from the holding element during the assembly process when the attachment screw is tightened. This extraction maintains the pretensioning force on the traction means while physically preventing the work eccentric from returning to the locked mounting position, thereby eliminating the risk of inadvertent relocking during operation.
Solution Approach 2:
The engagement structure is preliminarily engaged with the holding element during assembly to establish the correct pretensioning state. Once the attachment screw is tightened, this preliminary engagement is converted into a permanent separation, ensuring continuous tension on the traction means while preventing any possibility of relocking.
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 ensures nearly constant pretensioning force across varying operating conditions, simplifies assembly by allowing semi-automated setting of traction means force, and extends service life by addressing diameter, positional, and length tolerances, as well as temperature and dynamic effects.
Implementation Method 1
a torsion spring (9) for pretensioning the work eccentric (5)
Implementation Method 2
The spring device is preferably shaped in terms of the cross section of the spring wire so that this has a polygonal, in particular a square or flat cross section. Furthermore, the spring device is preferably shaped so that in the installed state, this is also at least slightly flattened
Implementation Method 3
The tensioning device according to the invention preferably comprises a damping or braking device, which as such is used for generating an eccentric braking moment, through which the pivoting of the work eccentric is braked
Implementation Method 4
at least one part of the loading force acting on this damping or braking device is generated or transmitted by the torsion spring (9)
Data Source
AI summary
An eccentric tensioning device for tensioning a traction means is provided. The eccentric tensioning device includes a track roller device having a running disk and a rolling bearing, a work eccentric for supporting the track roller device, the work eccentric being supported on an adjustment eccentric, a single torsion spring for pretensioning the work eccentric, and a fixing device for securing the work eccentric in a mounting position in which the torsion spring is located in a pretensioned state. The fixing device is positionable on a flange surface upon which the eccentric tensioning device is mountable during attachment, in which the running disk is forced radially relative to the rotating axis of the rolling bearing against the associated traction means under effect of the work eccentric, and a free switching path is traversed through an axial play being overcome against an axial force applied solely by the torsion spring.