Compact Belt Tensioner Spring for Low Axial Height
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Solution Overview
Problem
Conventional belt tensioning devices for belt drives with starter generators face challenges such as limited installation space, increased wear due to high torques, and difficulty in belt placement, particularly for double-arm tensioners.
Innovation Solution
A compact belt tensioning device with a coiled spring having 1.25 to 2.5 turns, where the winding ends have axial and radial offsets, allowing for a flat structure that minimizes axial height and maximizes angular extension, enabling efficient force transmission and assembly without additional space requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a conventional belt tensioning device with multiple coils is used, then the spring provides sufficient tensioning force, but the axial height increases and installation space is limited
Solution Approach 1:
The spring design transitions from a conventional multi-coil helical structure to a compact structure with only 1.25 to 2.5 coils, utilizing radial and axial offset configurations of the winding ends to achieve the required tensioning force within a minimized axial height envelope
2Force
If a double-arm tensioner is used, then belt tensioning is effective, but the device complexity and difficulty of belt placement increase
Solution Approach 1:
The invention extracts and eliminates one of the two tensioning arms found in conventional double-arm tensioners, reducing the structure to a single tensioning arm that pivots on the base body, thereby simplifying the overall device complexity while maintaining effective belt tensioning through the spring-loaded mechanism
3Length of moving object
If a compact spring design with fewer coils is used, then the axial height is minimized, but the tensioning force may be insufficient
Solution Approach 1:
The invention optimizes specific geometric parameters of the spring including the number of coils (1.25 to 2.5), the axial offset of the first winding end, and the radial offset of the second winding end, to achieve the required tensioning force within a compact axial height
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 provides a compact, easy-to-assemble belt tensioning device that decouples rotational fluctuations, ensures consistent force application, and allows for direct mounting on units like generators, reducing wear and eliminating the need for additional installation space, while maintaining effective belt tensioning.
Implementation Method 1
The spring is designed in the form of a coiled spring extending around a spring axis with a number of coils of at least 1.25 and a maximum of 2.5
Data Source
Figure 1a~1d
Figure 2a
Figure 2b~2c
AI summary
The spring (8) has a first winding end (42) comprising a first winding portion (48), which is inclined at an angle of 360 degrees about a spring axis (A8) and provided with an axial offset part, where the spring is formed with multiple 1.25-2.5 turns, which extend around the spring axis. A second winding end (49) is provided with a second winding portion (50), which is inclined at an angle of 360 degrees about the spring axis, where the second winding end includes a radial offset part (Vr). The first winding end forms an axial spacing, which is smaller than triple diameter of a spring wire. Independent claims are also included for the following: (1) a belt clamping apparatus (2) an aggregate arrangement for a belt drive.