Shift Actuator Cover Damping for Backlash-Induced Vibration Noise
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Solution Overview
Problem
The existing shift-by-wire actuator units for automatic transmissions experience noise due to vibration of the cover, caused by backlash in the speed reduction mechanism, which can resonate with the natural frequency of the cover, leading to undesirable noise.
Innovation Solution
Incorporating a shock absorption material between the control substrate and the cover in the actuator unit, which converts potential antinodes of vibration into nodes, reducing the amplitude of vibration and noise by generating additional nodes and thereby shortening the distance between them.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the cover is made rigid to protect internal components, then structural strength is improved, but vibration and noise increase when resonance occurs
Solution Approach 1:
A vibration damping sheet is introduced as an intermediary layer between the control substrate and the cover. This sheet serves as a mediator that absorbs and dissipates vibration energy, preventing the transmission of harmful vibrations and noise while maintaining the structural integrity of the rigid cover.
Solution Approach 2:
The natural frequency of the cover is modified by adding the vibration damping sheet, which changes the dynamic parameters of the system. This parameter change shifts the resonance frequency away from the operating range, preventing resonance-induced vibration and noise while preserving the cover's protective function.
2Object-generated harmful factors
If the distance between nodes of vibration is increased to reduce amplitude, then vibration amplitude is reduced, but the available space for component arrangement is reduced
Solution Approach 1:
The vibration damping sheet is selectively applied at specific locations where vibration nodes are formed, rather than uniformly across the entire cover. This local application creates additional nodes at precise positions, effectively reducing vibration amplitude in critical areas while preserving overall space for component arrangement.
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 shock absorption material effectively suppresses the vibration of the cover, reducing noise and ensuring that the control substrate and cover do not transmit vibrations, thereby minimizing noise generation.
Implementation Method 1
a shock absorption material is positioned between the control substrate and the cover, and contacts both the control substrate and the cover
Implementation Method 2
The shock absorption material effectively suppresses the vibration of the cover, reducing noise
Data Source
AI summary
An actuator unit that drives a switching mechanism for a shift range of an automatic transmission is provided. The actuator unit includes a motor that generates a drive force for driving the switching mechanism, a control substrate that controls the motor, a connector that connects a wire to the control substrate, a housing that includes an opening, a cover that covers the opening, and a shock absorption material that includes a first shock absorption material and a second shock absorption material. The motor and the control substrate are positioned in a housing space defined by the housing and the cover. The control substrate is fixed to the housing. The first shock absorption material and the second shock absorption material are positioned between the control substrate and the cover, and contacts both the control substrate and the cover.