Compact Belt Tensioner With Internal Pivot Axis
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Solution Overview
Problem
Existing belt tensioning devices for internal combustion engines with starter generators require significant space, complicate the positioning of belt pulleys, and involve high spring forces due to long lever arms, making them difficult to mount and remove.
Innovation Solution
A belt tensioning device with pivotable tensioning arms supported by spring means, where the pivot axis is positioned inside the driving belt pulley's diameter, allowing for a compact design that facilitates easy mounting and removal, and includes a housing that can be contact-free relative to the driveshaft, enabling direct attachment to the machine frame.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If the pivot axis of the tensioning arms is positioned outside the polygon formed by the different axes of rotation of the belt pulleys, then the belt tensioning device can provide adequate tensioning force, but the device requires a considerable amount of space and has a complicated operation for positioning the belt
Solution Approach 1:
The patent repositions the pivot axis from an external location to a position inside the driving belt pulley, utilizing the internal space of the pulley structure. This dimensional repositioning allows the tensioning arms to pivot within the pulley's footprint, eliminating the need for additional external space while maintaining the necessary tensioning force through optimized lever arm geometry.
Solution Approach 2:
The tensioning arms and pivot mechanism are nested within the driving belt pulley structure itself. The pivot axis is positioned inside the pulley, and the tensioning arms operate within the space defined by the pulley's diameter, effectively nesting the tensioning device within the existing pulley footprint rather than requiring separate external mounting space.
2Force
If the pivot axis of the tensioning arms is positioned outside the polygon formed by the different axes of rotation of the belt pulleys, then the belt tensioning device can provide adequate tensioning force, but the operation of positioning the belt is very complicated
Solution Approach 1:
By moving the pivot axis into the driving belt pulley, the patent creates a more direct and intuitive geometric relationship between the tensioning arms and the belt pulleys. This repositioning simplifies the kinematics of the system, making the belt positioning operation more straightforward and easier to control while maintaining adequate tensioning force.
3Force
If long tensioning arms are used to position the belt, then the belt can be tensioned, but long lever arms are provided which require high spring forces
Solution Approach 1:
The patent optimizes the parameters of the tensioning arms by positioning the pivot axis inside the driving belt pulley, which allows for shorter lever arms with more favorable mechanical advantage ratios. This parameter change reduces the required spring force while maintaining adequate belt tensioning capability, eliminating the need for excessively long tensioning arms that would demand high spring forces.
4Stability of the object's composition
If the housing is rigidly connected to the driving machine, then the belt tensioning device is stable, but the basic design of the driving machine is altered and mounting becomes more complex
Solution Approach 1:
The patent segments the mounting system by introducing a detachable connection between the housing and the driving machine. This allows the housing to be mounted stably during operation while enabling easy removal and repositioning when needed. The segmentation principle maintains stability during use but reduces mounting complexity by allowing the housing to be independently attached and detached without permanently altering the driving machine's basic design.
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 a compact, easy-to-mount and remove belt tensioning system that maintains the integrity of the driving machine's basic design, reducing space requirements and simplifying the arrangement of belt pulleys, while ensuring consistent belt tension across operational states.
Implementation Method 1
the tensioning arms are supported relative to one another by spring means
Data Source
AI summary
A belt tensioning device for a belt drive which comprises a driving machine with a driving belt pulley drivable by a driveshaft around a driving axis, and a plurality of further belt pulleys and with an infinite belt which is wrapped around the driving belt pulley and the further belt pulleys wherein the belt tensioning device comprises a housing in which two tensioning arms are supported so as to be pivotable around a common pivot axis, in which tensioning arms there are supported tensioning rollers with axes of rotation extending parallel to the driving axis, wherein the tensioning arms are supported relative to one another by spring means, wherein, with the driving belt pulley mounted at the driving machine, the housing can be mounted in that, in an annular region surrounding the driveshaft of the driving belt pulley, the housing is contact-free relative to the driving machine.