Range Switching Device with Opposite Control Valves
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Solution Overview
Problem
Conventional range switching devices for automatic transmissions, such as those using solenoid valves, fail to maintain functionality when one or more valves fail, preventing the vehicle from switching between drive, reverse, and neutral ranges.
Innovation Solution
A range switching device with a configuration of multiple control and switching valves driven by actuators, allowing for opposite oil pressure transmission characteristics, enabling switching between drive, reverse, and neutral ranges even when some valves fail, by using spool valves with specific port configurations and logical actuator patterns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional range switching device with solenoid valves is used, then the device structure is simple, but the vehicle cannot switch ranges when one or more valves fail
Solution Approach 1:
The range switching device is divided into multiple independent oil pressure transmission paths, each capable of performing the full range of switching operations. This segmentation ensures that if one path fails, other paths can still execute range switching functions, thereby improving reliability without requiring an overly complex unified system.
Solution Approach 2:
The patent introduces opposite oil pressure transmission characteristics as a key parameter change. By configuring spool valves with opposite port arrangements and control characteristics, the system creates redundant pathways that can compensate for failures. This parameter-based approach allows the system to maintain functionality despite valve failures while keeping the overall structure manageable.
2Reliability
If multiple control and switching valves are added to enable switching during valve failures, then the reliability improves, but the device complexity increases
Solution Approach 1:
Each independent oil pressure transmission path is designed to be universal, capable of performing all range switching operations (drive, reverse, neutral) independently. This multi-functionality allows any single path to take over complete control if others fail, achieving high reliability without requiring complex coordination between multiple specialized components.
Solution Approach 2:
The patent employs spool valves with inverted or opposite port configurations and control characteristics. By creating valves that operate in opposite manners, the system establishes redundant pathways where failure of one valve type can be compensated by its opposite counterpart, thereby improving reliability while maintaining a reasonable valve count through symmetric design.
3Reliability
If spool valves with opposite characteristics are used, then the range switching capability is maintained during failures, but the manufacturing complexity increases
Solution Approach 1:
The patent intentionally introduces asymmetry in the form of spool valves with opposite port configurations and control characteristics. While this may seem to increase manufacturing complexity, the symmetric nature of the opposite configurations actually facilitates standardized production processes, as the same manufacturing techniques can be applied to both normal and opposite-characteristic valves, merely with adjusted port arrangements.
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 continuous switching among drive, reverse, and neutral ranges, maintaining vehicle operability even during valve failures, while reducing device complexity and weight through shared spool valve configurations.
Implementation Method 1
a first control valve that is driven by a first actuator and controls an oil pressure transmitted from an oil pressure supply source to a downstream
Implementation Method 2
a first switching valve that is driven by a second actuator and can select an oil channel for transmitting the oil pressure transmitted from the first control valve to the downstream
Data Source
AI summary
A range switching device for performing switching the range of a transmission includes first control valve, a second control valve having a characteristic opposite to the first control, and first, second, third and fourth switching valves for controlling the transmission of oil pressures. The first and second switching valves cooperatively control the transmission of the oil pressure from the first control valve to a forward or reverse driving element (R). The third and fourth switching valve cooperatively control the transmission of the oil pressure from the second control valve to the forward or reverse driving element (R). The third and fourth switching valves each perform a substantially same oil pressure transmission when the state of the second and third actuators is reversed with respect to the first switching and second switching valves, respectively.