Power Latch Motor Shaft Mounting to Eliminate Axial Free Play
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Solution Overview
Problem
Existing vehicle closure panel power actuators suffer from axial free play or lash between drive and driven gears, leading to inefficiencies, reduced operable life, and undesirable vibration and noise.
Innovation Solution
A power actuator design with a drive shaft fixed to a drive gear, where axial biases are applied in opposite directions by bias members integrated with an annular seal to inhibit axial play, maintaining a direct and immediate driving relation between gears while preventing vibration and noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a drive gear and driven gear arrangement is used to transfer torque from the motor to the gear assembly, then torque transfer is achieved, but axial free play results in inefficiencies, reduced operable life, and undesirable vibration and noise
Solution Approach 1:
The patent applies parameter changes by introducing axial bias forces that modify the operational state of the drive shaft and gears. The bias members maintain constant axial compression on the drive shaft, ensuring the drive gear remains in firm contact with the driven gear throughout operation. This parameter change eliminates axial free play and maintains optimal torque transfer efficiency while extending operable life.
2Reliability
If a drive gear and driven gear arrangement is used to transfer torque, then torque transfer is achieved, but axial free play results in undesirable vibration and noise
Solution Approach 1:
The bias members continuously apply axial compressive forces to the drive shaft, maintaining constant contact between the drive gear and driven gear. This parameter change eliminates the axial free play that causes impact, vibration, and noise during gear engagement, resulting in smoother operation and reduced harmful vibrations and noise.
3Loss of energy
If bias members are integrated with an annular seal, then axial play is inhibited and torque transfer is improved, but device complexity increases
Solution Approach 1:
The bias members are integrated with the annular seal to form a single combined component. This merging of functions allows the seal to simultaneously perform its sealing function while also incorporating the biasing function through integrated biasing elements. The combined structure reduces the number of separate parts, simplifies assembly, and maintains effective torque transfer without excessive complexity.
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 eliminates axial play, ensuring precise torque transfer and reducing vibration and noise, enhancing the operable life and performance of the power actuator.
Implementation Method 1
A first bias member imparts a first bias along the axis in a first direction on one of the opposite ends of the drive shaft, and a second bias member imparts a second bias along the axis in a second direction, opposite the first direction, on the other of the opposite ends of the drive shaft to inhibit the drive shaft from having axial play.
Data Source
AI summary
A power actuator for a latch of a motor vehicle closure panel includes a housing having a first housing portion and a second housing portion. An electric motor is supported between the first housing portion and the second housing portion. The electric motor has a drive shaft extending along an axis between opposite ends. A drive gear is fixed to the drive shaft and a driven gear is meshed with the drive gear. An annular seal is compressed between the first housing portion and the second housing portion. A first bias member extends from the annular seal into engagement with one of the opposite ends of the drive shaft and a second bias member extends from the annular seal into engagement with the other of the opposite ends of the drive shaft. The first and second bias members are formed as a monolithic piece of material with the annular seal.