Gear Selector Gate Blocker Prevents Inadvertent Manual Mode Shift
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Solution Overview
Problem
Vehicles with automatic transmissions often experience unintended shifting into undesired modes of operation, leading to unnecessary engine speed increases when operators inadvertently shift from park to manual mode.
Innovation Solution
A gear selector assembly with a shift gate and a blocking device that requires two distinct motions to shift into the manual mode, preventing inadvertent selection by restricting direct movement from the park or drive modes to the manual mode, using a biasing member to ensure the blocking device does not interfere with intended shifts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a direct shift path is provided from park to manual mode, then ease of operation is improved, but reliability deteriorates due to inadvertent shifting
Solution Approach 1:
The shift path is segmented into multiple stages: first from park to drive mode, then from drive to manual mode. The gate blocker divides the single direct shift path into two separate motion sequences, forcing the operator to consciously perform two distinct actions rather than one accidental motion.
Solution Approach 2:
The gate blocker acts as an intermediary mechanism between the park position and manual position. It physically interrupts the direct path and requires the shift lever to pass through the drive position as an intermediate step, thereby preventing direct inadvertent shifting from park to manual.
2Reliability
If a blocking device is added to prevent inadvertent shifting, then reliability is improved, but device complexity increases
Solution Approach 1:
The gate blocker is designed as a movable, dynamic component rather than a fixed barrier. It can be displaced by the shift lever during legitimate two-stage shifting operations, allowing it to adapt to normal operation while still blocking inadvertent direct shifts from park to manual mode.
Solution Approach 2:
The gate blocker utilizes the existing shift lever motion and force to operate itself. During legitimate shifting, the shift lever's movement through drive mode automatically displaces the gate blocker to the non-blocking position, eliminating the need for separate actuation mechanisms or additional control systems.
3Object-affected harmful factors
If a gate blocker is positioned to restrict direct movement from park to manual, then harmful factors are reduced, but ease of operation worsens due to additional motion required
Solution Approach 1:
The gate blocker is positioned in advance to intercept and prevent the harmful direct shift path from park to manual mode. By placing this physical barrier beforehand, the system proactively prevents unintended mode selection before it can occur, rather than relying on post-prevention mechanisms.
Solution Approach 2:
The system requires the operator to perform a preliminary action (shifting to drive mode) before the second action (shifting to manual mode) can be executed. This preliminary step through drive mode ensures conscious operator intent before allowing access to manual transmission, reducing the risk of accidental engagement.
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
Prevents unintentional shifting into manual mode, ensuring operators perform conscious selections, thereby avoiding unnecessary engine speed increases and improving vehicle operation control.
Implementation Method 1
The gate blocker includes a biasing member configured to bias the gate blocker towards a nominal position
Data Source
AI summary
A gear selector assembly includes a shift gate including a plurality of gates, a gear selector movable between the plurality of gates and including a pawl, and a gate blocker positioned to restrictively interact with the pawl of the gear selector to selectively restrict movement of the gear selector through a first gate to a second gate. The gate blocker includes a biasing member configured to bias the gate blocker towards a nominal position. The gate blocker is configured to not restrictively interact with the pawl to allow the gear selector to move from the first gate to the second gate when the gate blocker is in the nominal position. Each gate of the shift gate is associated with a mode of operation of a vehicle.