Parking Lock Manual Release via Orifice Pressure Bleed
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Solution Overview
Problem
Existing parking lock devices require complex mechanisms to engage and disengage the piston and latch when the solenoid becomes inoperable, and they lack a simple manual release method, especially when the hydraulic or electrical systems fail.
Innovation Solution
A parking lock device with an unlock oil chamber and a lock oil chamber, where line pressure is transmitted to the unlock oil chamber and hydraulic pressure from an accumulator is transmitted to the lock oil chamber via solenoid valves, including a check valve and an orifice to simplify manual release, allowing operation without interference from the hydraulic actuator.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a solenoid and latch mechanism are used to control the parking lock, then the parking lock can be operated automatically, but the structure becomes complex when manual release is needed due to system failure
Solution Approach 1:
The patent extracts the manual release function from the automated solenoid-latch system by providing a separate manual release device that directly moves the piston. This allows the parking lock to be released manually without relying on the solenoid or latch mechanism, simplifying the overall structure while maintaining both automated and manual operation capabilities
Solution Approach 2:
The patent introduces a manual release device as an intermediary mechanism that directly actuates the piston bypassing the solenoid-latch system. This intermediary device enables manual operation without requiring modifications to the existing automated system, resolving the contradiction between automated control and manual release capability
2Reliability
If hydraulic pressure is accumulated in an accumulator for power supply loss, then the parking lock can be operated during power loss, but the manual release device may be interfered with by residual hydraulic pressure
Solution Approach 1:
The patent applies preliminary action by providing a manual release device that can be operated in advance or when needed, independent of the hydraulic system state. The device is designed to overcome residual hydraulic pressure through direct mechanical actuation, ensuring reliable manual release regardless of accumulator pressure
Solution Approach 2:
The manual release device creates a parallel, independent path for piston actuation that mirrors the hydraulic actuation function. This copied mechanism bypasses the need for hydraulic pressure to operate the parking lock release, eliminating interference from residual pressure while maintaining the same functional outcome
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
Enables simple and reliable manual release of the parking lock even when the hydraulic system fails, simplifying the mechanism and ensuring the parking lock can be released for towing or other methods, without the need for complex interference from the hydraulic actuator.
Implementation Method 1
the line pressure is transmitted to the unlock oil chamber
Implementation Method 2
a check valve configured to allow oil to flow toward the accumulator only is provided upstream of the accumulator
Implementation Method 3
a check valve configured to allow oil to flow toward the accumulator only is provided upstream of the accumulator
Implementation Method 4
an orifice is connected to the accumulator in parallel
Data Source
AI summary
In case of power supply loss, a parking lock is operated by moving a piston of a hydraulic actuator rightward by use of hydraulic pressure accumulated in an accumulator. If a hydraulic pressure generating source becomes unable to generate line pressure due to its failure after the power supply loss, it is desirable that the parking lock be releasable to tow a vehicle, for example. In that time, because the hydraulic pressure in the accumulator has got out via an orifice, the parking lock can be released by moving the piston in the hydraulic actuator leftward by use of a manual operation device without interruption by the hydraulic pressure accumulated in the accumulator. Because the hydraulic pressure in the accumulator is automatically released via the orifice, a complicated mechanism for enabling the manual operation device to work without interference from the hydraulic actuator becomes unnecessary.