Dual-Clutch Transmission Actuator Position Learning via Clutch Coupling
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Solution Overview
Problem
Current methods for learning the start position of the dog clutch in dual-clutch gearboxes are not sufficiently precise, leading to potential noise, shocks, and creaks during gear changes, as they rely on calculations of rib chain dispersions which are not accurate enough.
Innovation Solution
A method and device that detect the end of the synchronization phase, temporarily couple the clutch to the primary shaft to stop the actuator, and record the position when a specific force condition is met, allowing for precise determination of the dog clutch start position.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the dog clutch start position is learned using calculations of rib chain dispersions, then the learning process can be performed, but the precision of the determined position is insufficient leading to noise and shocks
Solution Approach 1:
The patent replaces the mechanical calculation method (rib chain dispersion calculations) with a sensor-based detection method. Force sensors directly measure the actual force applied during the dog clutch phase, and position sensors detect the precise actuator position when the force condition is met, substituting theoretical mechanical calculations with empirical sensor measurements to achieve higher precision.
Solution Approach 2:
The patent implements a feedback mechanism where force sensors continuously monitor the force applied by the actuator during the dog clutch phase. The control unit receives this force signal and compares it against predefined thresholds to dynamically determine when the actuator has reached the correct start position, using real-time feedback to achieve precise positioning rather than relying on pre-calculated values.
2Measurement precision
If the actuator is stopped using temporary clutch coupling to the primary shaft, then the position can be precisely determined, but the device complexity increases
Solution Approach 1:
The patent employs the system's own existing clutch mechanism to serve the dual purpose of both power transmission and actuator positioning. By temporarily coupling the clutch to the primary shaft, the system uses its inherent mechanical components to stop the actuator at the precise position, eliminating the need for separate positioning mechanisms and reducing overall device complexity.
Solution Approach 2:
The clutch mechanism is made multi-functional: it serves both its traditional role of power transmission and engagement control, and additionally functions as a positioning mechanism during the learning phase. This universal use of existing components achieves precise actuator positioning without adding dedicated positioning hardware, thereby avoiding increased device complexity.
Data Source
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AI summary
The invention relates to a method that allows the learning of positions of actuators (AC1, AC2) of a dual-clutch transmission (BV) that can be installed in a vehicle and comprises two parts (PB1, PB2) having an actuator (AC1) that can act on a synchroniser (S1) of a secondary shaft (AS1) in order to synchronise the speeds of an idler gear (PF) and a primary shaft (AP1) coupled to a clutch (EM1), and in order to couple said idler gear (PF) to the secondary shaft (AS1). Said method comprises a step in which, following a synchronisation phase involving an actuator (AC1) and a synchroniser (S1) in one of the parts (PB1), the beginning of their engagement phase is triggered and the clutch (EM1) is temporarily coupled to the primary shaft (AP1) in order to stop the actuator (AC1), and then when the force exerted on the synchroniser (S1) meets one condition, the position in which the actuator (AC1) stopped is recorded as the engagement starting position.