Automatic Transmission Pulley Thrust Detection via Extraction
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Solution Overview
Problem
Existing automatic transmission systems with electric motors for shifting face challenges in accurately evaluating axial forces due to interference from thrust bearings, leading to insufficient detection accuracy and responsiveness, especially when the axial force sensor is not precisely positioned relative to the roller.
Innovation Solution
A pulley propulsion device with a fixed pulley and a movable pulley capable of relative displacement, featuring a driving mechanism with an electric motor and a load sensor to detect the load applied on a fixed member, allowing for accurate pulley thrust detection without interference from rotation elements like thrust bearings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the axial force sensor is disposed on the rear surface of the threaded-spindle thrust bearing to detect axial force, then the detection structure is simple, but the detection accuracy deteriorates due to interference from roller rotation and thrust bearing disturbance
Solution Approach 1:
The load sensor is extracted from the rotating thrust bearing assembly and mounted on the stationary transmission case. This separates the detection function from the rotating components, eliminating interference from roller rotation while maintaining detection capability. The load sensor directly measures the reaction force on the fixed member without being influenced by thrust bearing disturbance.
Solution Approach 2:
The patent introduces a fixed member as an intermediary element between the movable pulley and the load sensor. This fixed member transfers the axial force reaction to the stationary load sensor mounted on the transmission case, enabling accurate force measurement while isolating the sensor from rotating components.
2Force
If the axial force sensor is positioned exactly at the rear of the roller to transmit axial force directly, then the detected load becomes larger, but the detection accuracy deteriorates when the thrust bearing rotates or stops
Solution Approach 1:
The detection system is extracted from the rotating thrust bearing environment and relocated to the stationary transmission case. The load sensor measures the reaction force on the fixed member without being subjected to rotational interference, ensuring consistent and accurate detection regardless of thrust bearing state.
Solution Approach 2:
Instead of measuring the axial force directly at the roller-thrust bearing interface where rotation causes interference, the patent inverts the measurement approach by detecting the reaction force on the stationary fixed member. This indirect measurement through the stationary structure eliminates the interference problem while maintaining force detection accuracy.
3Device complexity
If the thrust bearing is stopped or rotated at extremely low speed to position the roller, then the structure simplifies, but the responsiveness of axial force detection becomes insufficient
Solution Approach 1:
The detection system is extracted from the rotating thrust bearing assembly and mounted on the stationary transmission case. This eliminates the need for roller positioning or stopping to enable detection, as the load sensor continuously measures the reaction force on the fixed member regardless of thrust bearing rotation state, achieving high responsiveness without mechanical positioning.
4Measurement precision
If the load sensor is mounted on the fixed member whose rotation is regulated, then the pulley thrust detection accuracy improves, but the device complexity increases
Solution Approach 1:
The fixed member serves as an intermediary between the movable pulley and the load sensor. By mounting the sensor on this stationary component whose rotation is regulated by the rotation regulating member, the system achieves accurate thrust detection while utilizing existing structural elements, minimizing additional complexity.
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
Enables precise and responsive detection of pulley thrust, improving accuracy and reducing interference from rotation elements, thus enhancing the control of automatic transmission systems.
Implementation Method 1
a load sensor adapted to detect a load applied on the fixed member
Implementation Method 2
a driving mechanism having an electric motor and adapted to cause an output torque of the electric motor to be transmitted to the movable member
Implementation Method 3
a fixed member whose rotation with respect to a pulley case is regulated and adapted to give linear displacement to the movable member along the rotation axis of the pulley on the basis of rotation thereof
Data Source
AI summary
A pulley propulsion device for an automatic transmission, which includes a fixed pulley, and a movable pulley constituted capable of relative displacement along a rotation axis of a pulley with respect to the fixed pulley, is provided. The pulley propulsion device includes a movable member constituted capable of relative rotation around a rotation axis of the pulley with respect to the movable pulley, a fixed member whose rotation with respect to a pulley case is regulated and adapted to give linear displacement to the movable member along the rotation axis of the pulley on the basis of rotation thereof, a driving mechanism having an electric motor and adapted to cause an output torque of the electric motor to be transmitted to the movable member and to cause the movable pulley to generate a predetermined pulley thrust, and a load sensor adapted to detect a load applied on the fixed member.