Coupling Assembly Sensor for Transmission Shift Control
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Solution Overview
Problem
Powershift transmissions experience tip-in clunk and shift harshness due to the absence of a torque converter, leading to noise and mechanical linkage issues during acceleration from coasting, which conventional automatic transmission control strategies fail to adequately address without compromising driver expectations and performance.
Innovation Solution
A controllable coupling and control assembly with a sensor that includes a magnetic field sensing element, an electromechanical component, and a solenoid to provide an electrical signal for electronic transmission control, allowing for precise control of locking elements and speed sensing, thereby reducing parasitic losses and noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If a torque converter is used in automatic transmission, then shift harshness and noise are reduced, but power density and mechanical efficiency decrease
Solution Approach 1:
The patent removes the torque converter from the transmission system entirely, extracting the harmful fluid coupling element that caused power losses. Instead, it implements a direct mechanical coupling system with controlled engagement to achieve smooth shifts without the torque converter's parasitic losses.
Solution Approach 2:
The patent replaces the hydraulic-mechanical torque converter system with a purely mechanical coupling assembly featuring direct plate-to-plate contact. This mechanical substitution eliminates fluid dynamics losses while maintaining smooth power transfer through precision-engineered locking and unlocking mechanisms.
2Ease of operation
If conventional automatic transmission control strategies are used, then driver expectations are met, but tip-in clunk and shift harshness are not adequately addressed
Solution Approach 1:
The control system performs preliminary actions by pre-positioning the coupling assembly and adjusting engagement parameters before tip-in conditions occur. The system anticipates driver acceleration requests and prepares the mechanical coupling state to prevent clunking during the transition from coasting to acceleration.
Solution Approach 2:
The patent implements dynamic control of the coupling assembly where engagement and disengagement timing are continuously adjusted based on real-time operating conditions. The locking members and slide plate mechanism dynamically adapt to varying torque loads and rotational speeds to eliminate shift harshness while maintaining driver expectations.
3Power
If locking members are engaged to prevent relative rotation, then power transmission efficiency increases, but engagement noise and backlash increase
Solution Approach 1:
The patent applies local quality by creating different surface characteristics and geometric profiles at specific contact points of the locking members. The locking surfaces feature optimized curvature and friction characteristics that enable smooth engagement without impact noise, while maintaining high power transmission efficiency through localized high-friction zones.
Solution Approach 2:
The coupling assembly incorporates cushioning elements and compliant features that are pre-positioned to absorb engagement impacts before full locking occurs. The slide plate and locking members include built-in compliance mechanisms that cushion the transition from disengaged to engaged state, eliminating backlash and engagement noise.
4Measurement precision
If a sensor is added to the coupling assembly, then control precision and speed sensing improve, but device complexity increases
Solution Approach 1:
The patent merges the sensor directly into the coupling assembly structure, integrating the magnetic field sensing element with existing mechanical components. The sensor is embedded within the coupling housing or mounted on existing structural elements, combining measurement functionality with the power transmission structure to minimize additional complexity.
Solution Approach 2:
The coupling assembly is designed with multi-functionality where existing components serve dual purposes. The housing and structural elements that provide mechanical support also serve as mounting platforms for sensors, while magnetic components used for locking also function as reference elements for speed sensing, reducing the need for separate dedicated sensor components.
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 eliminates shift harshness and noise associated with tip-in clunk by enabling precise control of the coupling assembly, reducing backlash, and improving power density while being cost-effective and resistant to contamination and temperature variations.
Implementation Method 1
The sensor senses magnetic flux to produce an electrical output signal indicative of a speed of the relative rotation. A variable magnetic field is generated in response to rotation of the locking formations past the sensor.
Data Source
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.