Frame-Steered Vehicle Clutch Torque Distribution
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Solution Overview
Problem
Frame-steered vehicles face challenges in controlling wheel slip and distributing tractive force during cornering, leading to mechanical stress, reduced service life, and poor off-road performance due to uncontrolled rotational speed differences between axles.
Innovation Solution
A method involving controllable clutches that variably transmit torque and rotational speed, allowing for stepwise or continuous adjustment to balance speed between front and rear ground engagement elements, reducing mechanical stress and improving handling and off-road capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the drive to front and rear axles is mechanically linked to eliminate speed differences, then traction is improved, but wheel slip occurs at ground contact surfaces during cornering with superelevation, causing torque loads that reduce powertrain service life
Solution Approach 1:
The patent applies a dynamically controllable clutch device in the drive shaft connecting front and rear axles, replacing the static mechanically linked drive. This clutch can variably transmit torque and rotational speed based on real-time operating conditions, allowing the system to adapt between locked (high traction) and unlocked (low slip) states, thus resolving the contradiction between traction and wheel slip during cornering
Solution Approach 2:
The invention changes the torque transmission parameter dynamically by controlling the clutch engagement degree. By adjusting the clutch slip ratio and torque transmission characteristics based on steering angle and vehicle speed, the system optimizes the balance between maintaining traction and preventing excessive wheel slip at ground contact surfaces
2Object-generated harmful factors
If a differential is used to control rotational speed during cornering, then wheel slip is reduced, but uncontrolled wheel slip occurs when the product of vertical load and ground friction does not correspond to the torque ratio, limiting total tractive force
Solution Approach 1:
The patent implements a control system that monitors steering angle, vehicle speed, and clutch operating parameters to dynamically adjust clutch engagement. This feedback mechanism ensures the clutch operates in the optimal slip range, preventing both excessive wheel slip and loss of tractive force, thereby resolving the contradiction between wheel slip control and power transmission
3Reliability
If dog clutch is used to mechanically lock the differential, then wheel slip is limited, but speed differential during cornering manifests as wheel slip at ground contact surfaces, producing great torque loads
Solution Approach 1:
The patent replaces the static dog clutch with a dynamically controllable clutch that can progressively engage and disengage based on operating conditions. This allows smooth torque transmission during cornering, avoiding the sudden torque shocks and excessive wheel slip associated with mechanical locking, thus reducing torque loads on the powertrain
Solution Approach 2:
The controllable clutch acts as an intermediary between the differential and the drive axles, mediating the torque transmission. It provides a controlled slip mechanism that prevents the direct transmission of excessive torque loads to the ground contact surfaces while still maintaining effective traction, resolving the contradiction between limiting wheel slip and reducing torque loads
Data Source
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AI summary
The invention relates to a frame-steered vehicle (10) comprising a powertrain configured to provide drive torque to a transverse axle (16) in a front vehicle section (12) and at least one transverse axle (24, 26) in a rear vehicle section (20), wherein at least one longitudinal drive shaft (36, 38) is connected to the at least one transverse axle (24, 26) in the rear vehicle section (20). At least one controllable longitudinal clutch (80, 82) being variably adjustable between an engaged operational state and a disengaged operational state is arranged in the at least one longitudinal drive shaft (36, 38).