Vehicle Transmission Shift Lever Rack-and-Gear Packaging
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Solution Overview
Problem
Existing vehicle automatic transmission operation devices face challenges in downsizing while maintaining high rigidity and allowing arbitrary setting of moving distance and operation force, often resulting in increased weight and cost due to structural limitations.
Innovation Solution
The operation device features a bracket fixed to the vehicle body with a sliding portion and rotatably supported gears, including a rack gear and tooth surfaces, allowing gear change via a shift wire, which separates the sliding portion and gear structures to achieve high strength and compactness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the shift wire is directly connected to the shift knob with a slidable structure, then the moving distance of the shift knob directly becomes the moving distance of the shift wire, but it becomes difficult to arbitrarily set the moving distance and operation force of the shift knob
Solution Approach 1:
A gear mechanism is introduced as an intermediary between the shift knob and the shift wire. The gear includes a tooth surface at its outer circumferential portion, and a rack gear formed along the sliding direction of the sliding portion is engaged with the tooth surface. This allows the shift knob's sliding motion to be converted into rotational motion of the gear, which then pulls the shift wire, enabling arbitrary setting of moving distance and operation force through gear ratio adjustment.
2Strength
If the support portion has a structure with high rigidity to receive forces from all directions, then the support structure can handle multi-directional forces, but this leads to increases in weight and cost
Solution Approach 1:
The gear is extracted as a separate rotatably supported component from the sliding portion support structure. The gear includes a tooth surface at an outer circumferential portion, and the shift wire is connected to the gear at a position separated from the position where the gear is supported by the bracket. This separation allows the support portion to focus on providing stable support while the gear handles the force transmission, reducing the need for an overly rigid and heavy support structure.
3Volume of moving object
If the operation device is downsized to reduce internal spaces at mounting locations, then the device becomes more compact, but maintaining high rigidity and arbitrary setting of moving distance becomes difficult
Solution Approach 1:
The gear mechanism is nested within the compact operation device structure. The gear is rotatably supported by the bracket, and the sliding portion with the rack gear is integrated into the same compact space. This nested arrangement allows the device to maintain a small overall volume while incorporating the necessary gear mechanism for arbitrary setting of moving distance and maintaining rigidity.
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 design enables a thin, lightweight operation device with adjustable moving distance and operation force, reducing weight and cost while maintaining sufficient strength and improving mountability and operability.
Implementation Method 1
a rack gear that is formed along a sliding direction of the sliding portion and is engaged with the tooth surface of the gear
Implementation Method 2
the sliding portion including a rack gear that is formed along a sliding direction of the sliding portion and is engaged with the tooth surface of the gear, and gear change of the transmission being performed via the shift wire by causing the gear to rotate with sliding of the sliding portion
Data Source
AI summary
An operation device for a vehicle transmission is configured to include: a base bracket that is fixed to a vehicle body of a vehicle; a slider lever that is slidably supported by the base bracket and includes a shift knob; and a main gear, which is rotatably supported by the base bracket and includes gear teeth at an outer circumferential portion, to which an end portion of a shift wire of the vehicle transmission is connected at a position separated from a gear support shaft of the base bracket, the slider lever including a rack gear that is formed along a sliding direction of the slider lever and is engaged with the gear teeth of the main gear, and gear change of the transmission being performed by causing the main gear to rotate with sliding of the slider lever and pushing and pulling the shift wire.