Transmission Shaft Attenuation Mechanism for Torque Fluctuation Damping
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Solution Overview
Problem
Existing power transmission systems in electric and hybrid vehicles face challenges in inhibiting intense torque fluctuations from drive wheels without increasing the installation space, as current solutions like dynamic dampers and torque limiters result in larger device sizes.
Innovation Solution
A power transmission system with an attenuation mechanism that includes a support member and an inertia member engaged by friction, allowing the inertia member to rotate relative to the support member when torque fluctuations exceed a predetermined value, thereby attenuating torque fluctuations through friction without the need for a torsion spring or large torque transmission, allowing for a more compact design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a dynamic damper is attached to inhibit torque fluctuations, then torque fluctuations are reduced, but the device size increases excessively
Solution Approach 1:
The invention changes the engagement parameter from continuous (dynamic damper) to selective friction engagement. The friction engagement allows the inertia member to rotate relative to the support member only when torque fluctuations exceed a predetermined threshold, rather than continuously engaging as in dynamic dampers. This selective engagement based on torque magnitude enables effective fluctuation inhibition while maintaining a compact device size.
2Reliability
If a torque limiter is attached to inhibit torque fluctuations, then torque fluctuations are reduced, but the device size increases excessively
Solution Approach 1:
The invention changes the operational parameter from requiring transmission torque greater than or equal to drive torque (torque limiter) to using friction engagement that activates only when torque fluctuations exceed a predetermined threshold. This parameter change allows the attenuation mechanism to operate effectively at lower torque levels, avoiding the excessive device size associated with torque limiters while still inhibiting torque fluctuations.
3Reliability
If a dynamic damper is used, then torque fluctuations are inhibited, but the number of components and installation space increase
Solution Approach 1:
The invention extracts and eliminates the torsion spring component from the system. Instead of using a dynamic damper with a torsion spring, the patent employs a friction engagement mechanism where the inertia member rotates relative to the support member through friction alone. This extraction of the torsion spring reduces the number of components and simplifies the device structure while maintaining torque fluctuation inhibition capability.
4Reliability
If friction engagement is used for attenuation, then torque fluctuations are inhibited, but torque transmission efficiency may be reduced
Solution Approach 1:
The invention applies friction engagement partially rather than continuously. The friction engagement between the inertia member and support member activates only when torque fluctuations exceed a predetermined threshold, allowing full torque transmission during normal operation. This partial action approach inhibits torque fluctuations when needed while maintaining high torque transmission efficiency during normal conditions, minimizing energy loss.
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
This configuration effectively inhibits intense torque fluctuations without increasing installation space, allowing for a more compact and efficient power transmission system in electric and hybrid vehicles, while maintaining torque transmission efficiency.
Implementation Method 1
The inertia member is engaged by friction with the support member. When fluctuations in torque inputted to the attenuation mechanism from the drive wheel has the predetermined value or greater, the inertia member is rotated relatively to the support member while making contact by friction therewith.
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
It is intended to provide a power transmission system and an attenuation mechanism, both of which can inhibit intense fluctuations in torque inputted thereto from a drive wheel without increasing an installation space in an electric car or a high-power hybrid car. A power transmission system (100) includes an electric motor (3), a drive wheel (5), a transmission shaft (6) and an attenuation mechanism (7) . The transmission shaft (6) transmits a torque between the electric motor (3) and the drive wheel (5). The attenuation mechanism (7) is attached to the transmission shaft (6). The attenuation mechanism (7) includes a support member and an inertia member. The support member is attached to the transmission shaft (6). The inertia member is disposed to be rotatable relatively to the transmission shaft (6). The inertia member is engaged by friction with the support member.