Direct Drive Motor Clutch Locking Mechanism
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Solution Overview
Problem
Conventional vehicle wiper motors, including both general DC motors and electronically controlled DC motors, suffer from durability issues due to brush wear, noise, vibration, and harshness (NVH) problems, and lack precise control and efficiency due to mechanical linkage mechanisms. Additionally, direct drive motors lack a mechanism to prevent the motor shaft from moving when an external force is applied, causing unintended wiper operation.
Innovation Solution
A direct drive motor for vehicle wiper systems incorporates a clutch mechanism with a locking portion, comprising a housing, metal plate, magnet, and actuator, which uses magnetic forces to selectively engage and disengage the locking portion, preventing the motor shaft from moving when not in operation, thereby ensuring precise control and durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a direct drive motor is used without a locking mechanism, then the motor structure is simple and efficient, but the motor shaft can move unintentionally when external force is applied to the wiper arm
Solution Approach 1:
The patent extracts the locking function from the motor shaft itself and implements it through a separate clutch mechanism. The clutch includes a locking portion with teeth that can engage with corresponding teeth on the motor shaft, effectively extracting the fixation requirement from the main motor structure while providing reliable locking when needed.
Solution Approach 2:
The clutch mechanism transitions between two dynamic states: engaged state where the locking portion locks the motor shaft to prevent movement, and disengaged state where the motor shaft can rotate freely. This dynamic switching allows the system to adapt between requiring fixation and requiring rotation, resolving the contradiction between simple structure and reliable fixation.
2Reliability
If conventional DC motors with linkage mechanisms are used, then the motor shaft can be controlled, but durability is deteriorated due to brush wear and mechanical joints
Solution Approach 1:
The patent replaces the conventional mechanical linkage control system with a direct drive configuration where the motor shaft is directly connected to the wiper arm. This eliminates intermediate mechanical joints and linkages that cause wear and control imprecision, while maintaining control through electronic regulation of the brushless motor.
Solution Approach 2:
The patent removes the brush and mechanical linkage components from the system, extracting only the essential function of converting electrical energy to rotational motion. The clutch mechanism is added separately to provide the necessary locking function without introducing the wear problems of conventional DC motors.
3Measurement precision
If the motor shaft is forcibly fixed to prevent movement, then control precision is improved, but the motor cannot respond to external forces applied to the wiper arm
Solution Approach 1:
The clutch mechanism provides dynamic adaptability by switching between locked and unlocked states. When precision control is needed, the locking portion engages to fix the motor shaft. When external force needs to be accommodated, the clutch disengages to allow free rotation, enabling the system to adapt to different operational requirements.
Solution Approach 2:
The clutch mechanism prepares for potential external forces by providing a pre-configured locking mechanism. The locking portion with engaging teeth is ready to prevent unwanted movement, but can be quickly disengaged when external forces need to be accommodated, providing preliminary protection against control loss while maintaining adaptability.
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 enhances the durability and NVH performance of the direct drive motor by preventing unintended wiper movement and improving control precision, while maintaining efficiency by minimizing mechanical joints and reducing noise and vibration.
Implementation Method 1
a magnet provided in the operational direction of the metal plate and generating a magnetic force
Implementation Method 2
a wire formed on the metal plate and providing a polarity
Data Source
AI summary
A direct drive motor for a vehicle wiper system, which drives a wiper arm directly connected to a motor shaft may include a rotor for generating a rotational force, in which a sun gear connected to an upper portion of the rotor transmits the rotational force to a power transmission portion, a locking portion mounted on an upper inner surface of the rotor; and a clutch engaged with the locking portion and preventing the rotor from moving.