Dog Clutch Transmission Torque Control for Smooth Upshifts
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Solution Overview
Problem
Conventional speed change control devices experience prolonged engine output control times and large amplitude pitching due to half-meshing issues during gear changes, particularly when upshifting without disconnecting the clutch.
Innovation Solution
A dog clutch-type speed change device with a clutch that transitions between fully connected, partially connected, and disconnected states, controlled by a motive power source-torque adjustment device to manage torque and engagement of driving and driven dogs, reducing torque during disengagement and partial engagement to prevent pitching amplitude increases.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the conventional speed change control device determines half-meshing state based on driving-side number of rotations and cancels engine output restriction, then the speed change control is simplified, but the time for which engine output is controlled becomes prolonged and the amount of amplitude of pitching becomes large
Solution Approach 1:
The patent replaces the conventional mechanical control method (based solely on driving-side rotation detection) with a hybrid control system that combines mechanical state detection (driving-side rotation) with direct monitoring of dog engagement state. This substitution enables more precise control timing by detecting actual dog disengagement through the engagement detection device, thereby reducing prolonged control time while maintaining control logic simplicity.
Solution Approach 2:
The patent introduces a feedback mechanism where the engagement detection device continuously monitors the engagement state of the driving and driven dogs, and this information is fed back to the control device. The control device uses this real-time feedback to dynamically adjust engine output restriction timing, canceling the restriction precisely when dogs are fully disengaged rather than using fixed timing based solely on driving-side rotation, thus reducing control duration and pitching amplitude.
2Reliability
If the conventional speed change control device maintains engine output restriction until gear change completion, then gear switching reliability is improved, but the amount of amplitude of pitching increases and driver comfort deteriorates
Solution Approach 1:
The patent performs preliminary detection of dog disengagement state using the engagement detection device before completing the entire gear change process. When the detection device confirms that the driving and driven dogs are fully disengaged, the control device preliminarily cancels engine output restriction, even if gear switching is not yet fully complete. This preliminary action reduces pitching amplitude while maintaining reliability by ensuring dogs are properly disengaged before torque reduction.
Solution Approach 2:
The patent implements dynamic control of engine output restriction by continuously monitoring the engagement state of dogs through the engagement detection device. The control device dynamically adjusts the timing of engine output restriction cancellation based on real-time dog disengagement status rather than using fixed timing. This dynamic approach allows the system to adapt to varying gear change conditions, reducing pitching amplitude while ensuring reliable gear switching.
3Productivity
If the speed change control device increases torque after dog disengagement to maintain power transmission, then productivity is improved, but partial engagement of dogs may occur causing pitching
Solution Approach 1:
The patent uses the engagement detection device to provide continuous feedback on dog engagement state during torque adjustment. When the control device increases torque after dog disengagement, the detection device monitors whether partial engagement occurs. If partial engagement is detected, the control device can immediately adjust torque levels to prevent pitching, thus maintaining both productivity and engagement stability through real-time feedback control.
Solution Approach 2:
The patent implements dynamic torque control where the control device adjusts torque levels based on real-time dog engagement state detected by the engagement detection device. After initial dog disengagement, the control device can increase torque to maintain productivity, but continuously monitors engagement state and dynamically reduces torque if partial engagement occurs, preventing pitching while maintaining overall power transmission efficiency.
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 device effectively restricts pitching amplitude and eliminates partial engagement of dogs by managing torque adjustments based on engagement states, ensuring smooth and efficient gear changes.
Implementation Method 1
a clutch (44) that is configured to, in a fully connected state, transmit a torque from a motive power source (45) to a main shaft (41) as a clutch friction member is pressed
Data Source
Figure 1(a)~1(g)
Figure 2
Figure 3
AI summary
In a dog clutch-type speed change device (50) of a dog clutch-type automatic transmission including a clutch (44) that controls transmission of a torque from a motive power source (45) to a main shaft, a transmission (48) that switches gears, a motive power source-torque adjustment device (80) that adjusts the torque of the motive power source (45) when a speed change is performed, and a control device (90) that controls the motive power source-torque adjustment device (80), when changing a speed, the control device (90) reduces the torque of the motive power source (45) while the clutch (44) is in a fully connected state or a partially connected state and dogs are in an engaged state, increases the torque of the motive power source (45) that has decreased from disengagement until engagement and while the clutch (44) has been in the fully connected state or the partially connected state, and reduces the torque of the motive power source (45) again while the clutch (44) is in the fully connected state or the partially connected state so as to eliminate partial engagement of the dogs when they are engaging during a period in which the motive power source (45) is outputting an increased torque.