Torque Detector Using Pulse Gear for CVT Accuracy
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current methods for detecting torque input to continuously variable transmissions in vehicles lack accuracy, leading to increased power loss and fuel consumption due to higher hydraulic pressures needed to prevent chain slipping.
Innovation Solution
A torque detector system comprising a torque cam with a pulse gear and rotation pulse detection member that calculates torque based on the rate of pulses in a pulse train, allowing for precise detection of torque input, thereby reducing the need for excessive hydraulic pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If torque is estimated using intake air amount or radial strain detection, then the torque detection system is simple to implement, but the accuracy of torque detection becomes low
Solution Approach 1:
The patent replaces strain gauge-based electrical measurement with a mechanical pulse generation system. The torque cam converts axial thrust force from torque into rotational motion, which drives a pulse gear to generate pulses. This mechanical substitution achieves high-precision torque detection without requiring complex electrical strain measurement systems.
Solution Approach 2:
The patent introduces a torque cam as an intermediary mechanism between the torque input and the pulse output. The torque cam converts the axial thrust force into rotational displacement, which then drives the pulse gear. This intermediary mechanism enables accurate torque detection by translating mechanical torque into a measurable pulse signal.
2Reliability
If a larger margin is added to clamp pressure to prevent chain slipping, then chain slipping is prevented, but power loss in the oil pump increases and fuel consumption becomes high
Solution Approach 1:
The patent implements feedback control by using accurate torque detection to dynamically adjust the clamp pressure. The pulse signal from the torque cam reflects the actual torque input, enabling the control system to apply only the necessary clamp pressure to prevent chain slipping. This feedback mechanism eliminates the need for excessive margin in clamp pressure, reducing power loss in the oil pump.
3Productivity
If clamp pressure is set based on estimated torque with low accuracy, then the control system is simple, but excessive hydraulic pressure is generated leading to high fuel consumption
Solution Approach 1:
The patent replaces inaccurate estimation methods with a mechanical pulse generation system that directly reflects actual torque. The torque cam's rotational position and speed directly correspond to torque magnitude, providing real-time accurate torque measurement that enables precise clamp pressure control and improves fuel efficiency.
Solution Approach 2:
The patent changes the measurement parameter from indirect estimation (intake air amount or radial strain) to direct mechanical measurement through torque cam rotation. This parameter change enables accurate real-time torque detection, allowing the system to optimize clamp pressure and improve fuel efficiency.
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
Accurate detection of torque input reduces power loss in the oil pump and improves fuel efficiency by minimizing the margin added to the clamp pressure.
Implementation Method 1
a torque cam 10 provided on a rotating shaft and movable in an axial direction of the rotating shaft in accordance with torque input to the rotating shaft
Implementation Method 2
a rotation pulse detection member disposed so as to oppose the pulse gear, and configured to detect the at least one tooth of the pulse gear in rotation
Data Source
AI summary
A torque detector includes a torque cam, a pulse gear, a rotation pulse detection member, and a torque acquisition member. The torque cam is disposed on a rotating shaft and capable of moving in an axial direction of the rotating shaft according to torque input to the rotating shaft. The pulse gear includes a tooth formed on an outer circumferential surface of the torque cam. The rotation pulse detection member disposed so as to oppose the pulse gear is configured to detect the tooth of the pulse gear in rotation and to output a pulse train. The torque acquisition member is configured to acquire the torque from the pulse train. The tooth extends in the axial direction and a tooth thickness becomes continuously larger or smaller from a first side to a second side in the axial direction.