Dog Clutch Transmission Shift Design for Low-Impact Torque Transfer
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Solution Overview
Problem
Existing power transmission devices experience an impact (engagement sound and shock) due to the difference in rotational speeds of the first and second dog teeth before engagement, which affects torque transmission during gear shifts.
Innovation Solution
A power transmission device is designed with a friction clutch and a transmission system that includes a fixed gear, an idle gear, annular-shaped hubs, and a clutch ring. The system applies thrust in the axial direction to the clutch ring during engagement, ensuring that another first dog tooth and second dog tooth separate, thus reducing the impact during gear shifts. The inertia moment of the friction clutch is kept low by ensuring that its maximum torque (x) is greater than its inertia moment (y), where y ≤ 6 × 10^-6 * x.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the second dog tooth engages with the first dog tooth during gear shift, then torque transmission is achieved, but impact (engagement sound and shock) occurs due to rotational speed difference
Solution Approach 1:
The friction clutch is engaged before the dog tooth engagement to preliminarily connect the rotational motion. This preliminary action allows the rotational speeds to be more closely matched before the rigid dog tooth engagement occurs, reducing the impact shock. The clutch is disengaged after engagement to allow smooth separation without impact.
Solution Approach 2:
The friction clutch acts as a cushioning element before the dog tooth engagement. By engaging the clutch first, the system absorbs the rotational speed difference through friction rather than rigid impact. This beforehand cushioning protects the dog teeth from shock and reduces engagement noise.
2Object-affected harmful factors
If the friction clutch has large inertia moment to smooth engagement, then impact is reduced, but torque transmission capability is compromised
Solution Approach 1:
The friction clutch is designed with dynamic engagement and disengagement characteristics. The clutch engages and disengages smoothly through controlled friction, allowing the system to adapt to varying rotational speeds and torque requirements. This dynamic behavior enables the clutch to protect against impact while maintaining torque transmission capability across different operating conditions.
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 the impact (engagement sound and shock) during gear shifts by minimizing the kinetic energy difference between the engaging members, thereby enhancing the smoothness and efficiency of torque transmission.
Implementation Method 1
a friction clutch transmitting/interrupting power between a drive shaft coupled to a drive source and a first shaft
Implementation Method 2
thrust in the axial direction which makes another first dog tooth and the second dog tooth of another clutch ring separate from each other is applied to the clutch ring
Data Source
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AI summary
Provided is a power transmission device (1) that can reduce impact while eliminating torque shortage during gear shifting. The power transmission device comprises: a friction clutch (11) that transmits and blocks power between a first shaft (4) and a drive shaft (3) linked to a drive source (S); and a transmission (2) to which power is inputted by the first shaft, the transmission being provided with thrust generators (56, 86) that, when second dog tooth (83) of clutch rings (80) mesh with first dog tooth (53), apply axial thrust to the clutch rings (80) so as to separate other first dog tooth (43) from other second dog tooth (83). The relationship y ≤ 6 × 10-6 is satisfied, where x is the maximum torque (Nm) of the drive source and y is the moment of inertia (kgm2) of the friction clutch.