Transmission Parking Lock Apparatus with Shared Actuator
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Solution Overview
Problem
Shift-by-wire type transmissions that convert driver input into electrical signals for operating a meshing type clutch lack a manual valve for hydraulic clutch control, making it impossible to operate a parking lock mechanism using an actuator.
Innovation Solution
A parking lock apparatus that integrates a parking gear, a parking pawl, and a parking pawl drive member within the gearshift member operated by an actuator, allowing the parking lock to be engaged when the gearshift member moves from a neutral position, thereby combining gear shifting and parking lock functions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If a shift-by-wire type transmission uses an actuator to operate a meshing type clutch for gear shift control, then gear shift automation is improved, but the ability to operate a parking lock mechanism is lost due to lack of manual valve
Solution Approach 1:
The gearshift member is designed to perform multiple functions: it operates the meshing type clutch for gear shift control and simultaneously operates the parking pawl for parking lock mechanism. This multi-functionality resolves the contradiction by enabling the parking lock to be operated through the existing actuator-driven gearshift member without requiring a separate manual valve or additional actuator.
2Adaptability or versatility
If a separate actuator is added to operate the parking lock mechanism in a shift-by-wire transmission, then parking lock operation capability is improved, but device complexity and component count increase
Solution Approach 1:
The gearshift member is designed to perform multiple functions: it operates the meshing type clutch for gear shift control and simultaneously operates the parking pawl for parking lock mechanism. This multi-functionality resolves the contradiction by enabling the parking lock to be operated through the existing actuator-driven gearshift member without requiring a separate manual valve or additional actuator.
Solution Approach 2:
The operation mechanisms for gear shift and parking lock are merged into a single gearshift member. The gearshift member's movement in different directions from the neutral position simultaneously controls both the meshing type clutch and the parking pawl, combining two separate functions into one integrated mechanism.
3Device complexity
If the gearshift member is designed to operate both meshing type clutch and parking pawl, then component count is reduced, but the precision of gear position establishment and parking lock engagement may be compromised
Solution Approach 1:
The gearshift member has different operational characteristics for different functions: in one direction it operates the meshing type clutch for precise gear position establishment, and in another direction it operates the parking pawl for parking lock engagement. Each function utilizes the gearshift member's movement in its optimal direction, maintaining precision for both operations despite the integrated design.
Data Source
AI summary
A parking lock apparatus for a transmission including a meshing type clutch is provided in which when a parking lock is operated by engaging a parking pawl (43) with a parking gear (41) provided on a gear shaft of a transmission, since a parking rod (51) for operating the parking pawl (43) is provided on a shift rod (44) connected to and operated by an actuator (46) in order to establish a reverse gear position on the transmission, it is possible to establish the reverse gear position with a shift fork (48) by moving the shift rod (44) in one direction from the neutral position, and to carry out the operation of the parking lock automatically without requiring a special actuator by moving the shift rod (44) in another direction from the neutral position, thereby reducing the size and cost of the transmission by enabling the number of components, including the number of actuators (46), to be cut.