Coupling Assembly Sensor for Powershift Transmission Control
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Solution Overview
Problem
In powershift transmissions, the absence of a torque converter leads to tip-in clunk and shift harshness due to mechanical linkage without fluid coupling, necessitating a control strategy that addresses unique operating characteristics to eliminate noise and harshness without interfering with driver expectations or performance.
Innovation Solution
A controllable coupling and control assembly with a sensor that includes a magnetic field sensing element to provide an electrical signal for electronic transmission control, featuring a locking element and ferromagnetic locking formations, and an electromechanical component that moves the locking element across a gap in response to an electrical control signal, preventing relative rotation and sensing speed through magnetic flux.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a mechanical linkage without fluid coupling is used in powershift transmissions, then mechanical connection and power transfer are achieved, but tip-in clunk and shift harshness occur due to absence of torque converter
Solution Approach 1:
The patent introduces a controllable coupling assembly with locking elements as an intermediary mechanism between the mechanical linkage and the transmission. This coupling assembly selectively engages or disengages based on operating conditions, acting as a mediator that prevents direct mechanical coupling during tip-in conditions while maintaining reliable power transfer during normal operation, thereby eliminating tip-in clunk without sacrificing mechanical connection reliability
Solution Approach 2:
The coupling assembly is designed with movable locking elements that can dynamically change their engagement state based on real-time operating conditions. The locking elements can be actuated to engage or disengage the coupling, allowing the system to adapt its mechanical connection characteristics dynamically, preventing harshness during transient tip-in conditions while maintaining solid mechanical connection during steady-state operation
2Reliability
If a sensor is added to provide speed sensing for electronic transmission control, then shift quality and tip-in clunk elimination are improved, but device complexity increases
Solution Approach 1:
The patent combines the speed sensing function directly into the coupling assembly by mounting the sensor on the assembly itself rather than as a separate external component. The sensor is integrated with the locking elements and coupling structure, merging multiple functions (coupling, locking, and speed sensing) into a single integrated unit, thereby reducing overall system complexity while maintaining improved shift quality and noise reduction capabilities
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
The solution effectively reduces shift harshness and noise associated with tip-in clunk by providing precise control and speed sensing, enhancing the performance and reliability of powershift transmissions.
Implementation Method 1
The sensor senses magnetic flux to produce an electrical output signal indicative of a speed of the relative rotation
Implementation Method 2
A variable magnetic field is generated in response to rotation of the locking formations past the sensor
Data Source
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AI summary
A coupling and control assembly including a sensor for providing an electrical signal for electronic transmission control is provided. The assembly includes a first coupling member which supports the sensor and a locking element and a second coupling member supported for rotation about a rotational axis. The second coupling member has a coupling face oriented to face radially with respect to the axis and has a set of ferromagnetic or magnetic locking formations. An electromechanical component is also supported by the first coupling member. Both the locking element and the sensor are in close-spaced opposition to the coupling face. The sensor senses magnetic flux to produce an electrical output signal indicative of a speed of rotation of the second coupling member. A variable magnetic field is generated in response to rotation of the locking formations past the sensor.