CVT Driver Pulley Roller Weight Guide Radial Ramp
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Solution Overview
Problem
Existing continuously variable transmissions (CVTs) in personal tracked vehicles face inefficiencies in torque delivery and gear ratio management, particularly at varying speeds and inclines, limiting their performance across different terrains.
Innovation Solution
A CVT system with a driver pulley assembly featuring moveable and fixed sheaves with cones, an endless belt, and a roller weight guide with radial ramp structures, allowing the separation between cones to change and optimizing torque delivery and gear ratios through the movement of roller weights along guide rails and ramp structures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a traditional CVT system is used, then the vehicle can operate on different terrains, but the torque delivery and gear ratio management are inefficient at varying speeds and inclines
Solution Approach 1:
The patent implements dynamic adjustment of the gear ratio through a variable diameter pulley system where the drive pulley diameter changes based on vehicle speed and load conditions. At low speeds, the drive pulley diameter is smaller to provide higher torque multiplication, while at high speeds, the diameter increases to reduce torque requirements and improve efficiency. This dynamic adaptation resolves the contradiction by allowing the system to maintain optimal torque delivery efficiency across varying terrain conditions.
Solution Approach 2:
The system changes the physical parameter of pulley diameter continuously to optimize performance. The drive pulley diameter is varied according to the vehicle's operating conditions, enabling efficient torque delivery at both low and high speeds. This parameter change approach allows the CVT to adapt to different terrains while maintaining productivity.
2Power
If the engine rotational speed is high at low vehicle speeds, then power is available, but excessive torque is delivered to the drive sprocket wheel
Solution Approach 1:
The variable diameter pulley system dynamically adjusts the drive pulley diameter based on the ratio of engine speed to vehicle speed. When engine speed is high at low vehicle speeds, the system selects a smaller drive pulley diameter to reduce the torque multiplication effect, thereby delivering appropriate torque to the drive sprocket wheel while still utilizing the available engine power effectively.
3Use of energy by moving object
If the engine rotational speed is low at high vehicle speeds, then fuel consumption is reduced, but insufficient torque is delivered to the drive sprocket wheel
Solution Approach 1:
The system dynamically adjusts the drive pulley diameter to be larger at high vehicle speeds, which reduces the gear ratio and allows the engine to operate at lower rotational speeds while still delivering sufficient torque to the drive sprocket wheel. This maintains fuel efficiency while ensuring adequate torque delivery for high-speed operation.
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
Enhances operational efficiency by dynamically adjusting gear ratios and torque delivery, improving vehicle performance across different terrains and speed conditions.
Implementation Method 1
A plurality of roller weights is mounted on the plurality of guide rails... Each of the plurality of roller weights is adapted to roll along at least one of the plurality of guide rails in a radial direction of the roller weight guide. The roller weights are adapted to move radially outwards with increasing rotation speed of the roller weight guide.
Data Source
AI summary
A driver pulley assembly for a continuously variable transmission (CVT) includes a roller weight guide, having an inner and outer periphery, adapted to be mounted on the main shaft of the CVT. A plurality of ramp windows extend radially along the roller weight guide. A pair of guide rails extend along opposite edges of each ramp window. A plurality of roller weights, mounted on the pair of guide rails, is adapted to move along the pair of guide rails in a radial direction of the roller weight guide. A ramp structure, coinciding with the ramp window, extends in the radial direction of the roller weight guide and abuts the plurality of roller weights. The roller weighs are adapted to move radially outwards along the ramp structure with increasing rotational speed of the roller weight guide. The ramp structures have ramp profiles. CVT systems and vehicles including the driver pulley assembly are also included.