Vehicular Parking Lock Solenoid Valve Reduction
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Solution Overview
Problem
The existing vehicular parking lock devices for automatic transmissions require a large number of solenoid valves in their hydraulic circuits, which is undesirable and can lead to increased complexity and potential malfunctions.
Innovation Solution
A vehicular parking lock device with a hydraulic circuit that uses a reduced number of solenoid valves, where a first solenoid valve supplies line pressure for parking lock release, a second solenoid valve and a third solenoid valve supply line pressure for parking lock operation, and the first or second solenoid valve also functions for the starting mechanism or hydraulic engagement devices, with an accumulator providing redundancy during idling stop control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a separate solenoid valve is added for the parking lock device, then the parking lock function is improved, but the number of solenoid valves increases and device complexity increases
Solution Approach 1:
The patent applies multi-functionality by enabling existing solenoid valves (first and second solenoid valves) to serve dual purposes: controlling both the starting mechanism/hydraulic engagement devices and the parking lock device. The first solenoid valve can supply hydraulic pressure to either the starting mechanism or the parking lock, while the second solenoid valve can supply hydraulic pressure to either the hydraulic engagement devices or the parking lock, eliminating the need for dedicated solenoid valves for the parking lock function.
2Device complexity
If the same solenoid valve is used for multiple functions, then the number of solenoid valves is reduced, but the reliability decreases due to potential malfunctions
Solution Approach 1:
The patent implements beforehand cushioning by providing redundant hydraulic pressure supply paths through the accumulator. The accumulator stores hydraulic pressure in advance and can supply pressure to the parking lock device independently when solenoid valves malfunction or during engine idling stop, ensuring the parking lock function remains reliable even when shared solenoid valves fail.
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
This configuration reduces the total number of solenoid valves and accumulators, enhances redundancy by allowing the parking lock to function even with solenoid valve malfunctions, and ensures automatic operation, thereby simplifying the hydraulic circuit and improving reliability.
Implementation Method 1
an accumulator in which a pressure is stored by the line pressure
Data Source
AI summary
In a vehicular parking lock device, the parking lock is actuated when a line pressure is supplied to a left end of a hydraulic actuator (25) via a second solenoid valve (32A), or a hydraulic pressure of an accumulator (37, 38) is supplied to the left end of the hydraulic actuator (25) via a third solenoid valve (32B), and the parking lock is released when a line pressure is supplied to a right end of the hydraulic actuator (25) via a first solenoid valve (32C, 32D). The second solenoid valve (32A) and the first solenoid valve (32D) also function as a solenoid valve that supplies the hydraulic pressure to a torque converter (40) and a solenoid valve that supplies the hydraulic pressure to a hydraulic brake (41) for shift change, respectively. Thus, it is possible to decrease the total number of solenoid valves, thereby cutting the number of components of a hydraulic circuit (31).