Variable-Spaced Flange Pulley With Torque-Locked Mode Switching
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Solution Overview
Problem
Existing continuously variable transmission (CVT) systems in vehicles require costly and space-intensive electric motors for managing transmission ratios, which limits their efficiency and flexibility in switching between performance modes.
Innovation Solution
A pulley design with a fixed and movable shroud, where the movable shroud is mechanically controlled by a torsion spring and locking mechanism, allowing for two operational modes: a 'normal' mode where the assemblies rotate relative to each other based on load, and a 'high-performance' mode where the assemblies are locked, utilizing a radially extending finger and torsion spring system to adjust the transmission ratio based on torque and speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If an electric motor is used to control the shroud spacing for managing transmission ratio, then the transmission ratio can be electronically managed under all operating conditions, but the cost price and space requirement increase significantly
Solution Approach 1:
The patent replaces the electric motor system with a purely mechanical control system. The mechanical assembly includes a control cam, follower, and linkage that automatically adjust the shroud spacing based on operating conditions without requiring electronic sensors, motors, or control electronics, thereby reducing both cost and space requirements while maintaining transmission ratio management capability
Solution Approach 2:
The mechanical assembly operates autonomously using the engine's own operational parameters. The control cam is driven by the engine shaft, and the follower automatically responds to centrifugal force and spring tension based on engine speed and load, eliminating the need for external power sources or electronic control systems
2Adaptability or versatility
If an electric motor is used to control the shroud spacing for managing transmission ratio, then the transmission ratio can be electronically managed under all operating conditions, but the cost price increases
Solution Approach 1:
The patent employs simple, inexpensive mechanical components such as a control cam, follower, spring, and linkage instead of costly electric motors and electronic control systems. These mechanical parts are easier and cheaper to manufacture, requiring no complex electronics, sensors, or power management systems
Solution Approach 2:
The patent replaces the expensive electric motor system with a purely mechanical control system. The mechanical assembly includes a control cam, follower, and linkage that automatically adjust the shroud spacing based on operating conditions without requiring electronic sensors, motors, or control electronics, thereby reducing both cost and space requirements while maintaining transmission ratio management capability
3Adaptability or versatility
If a mechanical system with locking means is used to switch between operational modes, then the system can switch between normal and high-performance modes, but the device complexity increases
Solution Approach 1:
The patent divides the control system into distinct functional segments: a control cam for setting positions, a follower for sensing, a spring for providing force, and a locking mechanism for mode switching. This segmentation allows each component to perform its specific function simply, and the overall system remains manageable despite having multiple operational modes
Solution Approach 2:
The patent uses a dynamic locking mechanism that can transition between locked and unlocked states based on operational requirements. The locking means engage or disengage to switch between normal and high-performance modes, allowing the system to adapt its degree of freedom and control based on the desired operating condition
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 mechanical solution enables efficient and cost-effective management of transmission ratios, allowing users to switch between modes without the need for complex and expensive motorized systems, optimizing vehicle performance and fuel efficiency.
Implementation Method 1
a second assembly, which is mounted on the shaft by way of at least one torsion spring such that the relative angular position of the second assembly with respect to the shaft depends on the torque transmitted by the shaft
Implementation Method 2
the locking means have for example, for the one part, a radially extending finger and, for the other part, a hole made in a peripheral wall, the finger being able to move between a position in which it is located entirely inside the peripheral wall and a position in which it projects into the hole made in the peripheral wall
Data Source
AI summary
Disclosed is a pulley having: a shaft; a first shroud, called the fixed shroud, mounted so as to be unable to move in translation with respect to the shaft; a second shroud, called the movable shroud, mounted to be driven in rotation by the shaft but is able to move longitudinally with respect to the latter; a mechanism for mechanically controlling the longitudinal movement of the second shroud with respect to the shaft, having: —a first assembly, which is mounted on the shaft and driven in rotation by the latter, —a second assembly, which is mounted on the shaft by way of at least one torsion spring such that the relative angular position of the second assembly with respect to the shaft depends on the torque transmitted by the shaft, and —a device for locking in at least one position between the first assembly and the second assembly.