Noiseless Shifter Park Lock via Magnetic Biasing
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Solution Overview
Problem
Modern transmission shifters with solenoid-based park lock systems create audible noise when operating, which can be misinterpreted as a vehicle defect, especially in quieter vehicles like electric vehicles, and require a solution that minimizes parts, is easy to assemble, durable, and noiseless.
Innovation Solution
A park lock system using a permanent magnet and electro-magnet with an electrical circuit that activates the electro-magnet when predetermined vehicle conditions are met, allowing the shift lever to be moved out of the park position without using a solenoid or noisy electro-mechanical devices, utilizing a ramp lever and blocker mechanism with a bias spring to maintain the shift lever in a locked position until conditions are met.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a solenoid-based park lock system is used to prevent shifting out of park position, then the park lock function is achieved, but audible noise is generated when the solenoid operates
Solution Approach 1:
The patent replaces the solenoid-based mechanical actuation system with an electromagnetic field-based system. A permanent magnet on the blocker interacts with an electro-magnet on the base to hold or release the blocker without mechanical movement of the electro-mechanical actuator, thereby eliminating the audible click noise while maintaining the park lock function.
Solution Approach 2:
The patent removes the noisy solenoid component from the system and replaces it with a magnetic field-based actuation mechanism. By extracting the problematic mechanical-solenoid element and substituting it with electromagnetic interaction between permanent and electro-magnets, the harmful noise is eliminated while the functional requirement remains satisfied.
2Object-generated harmful factors
If a noiseless park lock system is implemented, then audible noise is eliminated, but the system complexity increases
Solution Approach 1:
The electro-magnet on the base serves multiple functions: it interacts with the permanent magnet on the blocker to both hold the blocker in the pawl-blocking position and release it when activated. This multi-functional electromagnetic interaction simplifies the overall system compared to traditional multi-component mechanical locking mechanisms, reducing complexity while achieving noiseless operation.
Solution Approach 2:
The permanent magnet on the blocker acts as an intermediary that translates the electromagnetic field activation into mechanical positioning of the blocker. This intermediary approach allows the system to achieve complex positioning and locking functions through simple electromagnetic activation without requiring complex mechanical linkages or multiple actuators.
3Reliability
If a solenoid is used to actively release the shifter from park, then the park lock function is reliable, but the solenoid creates a clicking noise that may be misinterpreted as a vehicle defect
Solution Approach 1:
The patent replaces the mechanical solenoid actuation system with an electromagnetic field-based system. The electro-magnet on the base interacts with the permanent magnet on the blocker to release the pawl-blocking position without the mechanical clicking noise of a solenoid, thereby maintaining reliable park lock release function while eliminating the harmful perception of vehicle defects.
Solution Approach 2:
The patent converts the potential harm of noisy operation into a benefit by using electromagnetic interaction instead of mechanical solenoid actuation. The electromagnetic field provides smooth, noiseless actuation of the blocker, transforming what would have been a harmful clicking noise into a beneficial quiet operation that enhances vehicle refinement and prevents misinterpretation as defects.
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 system effectively prevents shifting out of the park position until vehicle conditions are met without creating noise, ensuring a quiet operation and reducing the risk of misinterpretation as a vehicle defect, while maintaining durability and simplicity.
Implementation Method 1
the electro-magnet creates a magnetic force biasing the blocker toward the pawl-unblocked position and pressing the blocker against the ramp lever
Implementation Method 2
a permanent magnet on the blocker and a corresponding electro-magnet on the base
Implementation Method 3
a bias spring biasing the ramp lever to the under-pawl position
Data Source
AI summary
A transmission shifter includes a base, a shift lever movable between gear positions, and a pawl, a pawl blocker, a permanent magnet, an electro-magnet, and an electrical circuit for selectively activating the electro-magnet when a predetermined vehicle condition is sensed. The permanent magnet's attraction to an iron based surface of the electro-magnet normally holds the blocker in a pawl-blocking position, keeping the shift lever in park position, until the electrical circuit activates the electro-magnet and the pawl is depressed. When activated, the electro-magnet biases the blocker toward a pawl-unblocked position. A ramp lever keeps the pawl blocker in the park position until the pawl mechanically moves the ramp lever and magnetically-biased blocker together, thus allowing the shift lever to be moved from park position. The park lock system is characterized by an absence of movement in response to an electrical signal to an electro-mechanical device and thus operates noise-free.