Herringbone Toothed Belt with Variable Transverse Stiffness
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Solution Overview
Problem
Existing belt-type traction systems, particularly herringbone toothed belts, face issues with uneven tooth force distribution leading to excessive stress on drive wheel teeth and rapid wear, especially in long belt applications like elevators, due to axial tolerances and alignment inaccuracies.
Innovation Solution
A herringbone toothed belt with edge parts and a center part having different spring constants, where the center part is more flexible in the transverse direction, allowing for even force distribution and reduced tooth force on the drive wheel, enabling the use of smaller components and improved endurance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the belt is made flexible by using soft reinforcements to adapt to axial tolerances of wheels, then the belt can accommodate alignment inaccuracies and reduce wear, but the belt elongates excessively in long belt applications such as elevators
Solution Approach 1:
The belt is designed with different local properties: the edge parts contain rigid reinforcements (steel wires or braids) to prevent elongation, while the center part uses flexible reinforcements to adapt to axial tolerances. This local differentiation allows the belt to simultaneously achieve adaptability to alignment inaccuracies and control elongation in long belt applications.
2Length of moving object
If rigid reinforcements are used to minimize belt elongation in long belt applications, then belt elongation is reduced, but the alignment accuracy requirements for traction sheaves and diverting pulleys become extremely stringent
Solution Approach 1:
The belt structure differentiates between edge parts with rigid reinforcements and a center part with flexible reinforcements. This allows the belt to have overall low elongation while locally accommodating alignment variations in the center region, thereby reducing the stringency of alignment accuracy requirements for traction sheaves and diverting pulleys.
Solution Approach 2:
The belt is segmented into multiple reinforcement zones with different stiffness characteristics. The edge zones provide structural stability and minimal elongation, while the central zone provides flexibility to absorb misalignment, effectively dividing the functional requirements across different spatial regions.
3Length of moving object
If tooth forces are concentrated on few teeth due to rigid belt structure, then belt elongation is controlled, but the teeth of drive wheel are overstressed and wear rapidly
Solution Approach 1:
The belt employs different reinforcement stiffness in different regions: rigid edge reinforcements control overall elongation while the flexible center reinforcement allows local deformation that distributes tooth forces across multiple teeth of the drive wheel, preventing tooth overstress and rapid wear.
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 reduces tooth force on drive wheel teeth, allows for smaller component sizes, enhances belt endurance, and decreases noise, while enabling efficient elevator operation with lower dimensional accuracy requirements for sheaves and pulleys, resulting in reduced costs and improved space efficiency.
Implementation Method 1
the center part (4) in the center of the toothed belt (1) in the cross-section of the toothed belt (1) is arranged to flex in the transverse direction more than the edge parts (2) of the toothed belt (1)
Data Source
Figure 1
Figure 2~3
Figure 4
AI summary
The object of the invention is a belt-type traction means, which comprises a herringbone toothed belt (1), which has at least a tooth part (la) and a support structure (2a) supporting the tooth part (la), which support structure (2a) comprises a plurality of reinforcement means (3) in the longitudinal direction of the toothed belt (1). In the transverse direction of the toothed belt (1) the toothed belt (1) comprises two edge parts (2) side by side and a center part (4) between the edge parts (2) connecting the edge parts (2), the spring constant of which center part in the transverse direction of the toothed belt (1) is smaller than the corresponding spring constant of the edge parts (2). In addition, the object of the invention is a method for fabricating the aforementioned traction means (1) and the use of the traction means in an elevator as well as an elevator provided with the aforementioned traction means (1).