Dual-Axis Shift Lever With Cam Return for Work Vehicle Transmissions
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing operation devices for work vehicles, such as tractors, face complexity in switching transmission modes, leading to reduced operability due to multiple shift operation devices and potential unintended interactions during operation.
Innovation Solution
An operation device with a rotatable operation lever, urging portion, and cam portions that detect and transmit rotations to switch between neutral, forward, and backward states, featuring separate transmission paths to prevent unintended contact and improve user interface, including a movement holding portion to return the lever to initial positions and hold it at specific states.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple shift operation devices are provided in a driver's seat, then the transmission can be switched among forward, reverse, and neutral states, but the operation becomes complicated and unintended interactions occur between devices
Solution Approach 1:
The patent combines multiple shift operation functions into a single operation lever that can rotate about two non-parallel rotation shafts. This single lever integrates the functionality of multiple separate shift devices, allowing the transmission to be switched among forward, reverse, and neutral states without requiring multiple separate operation devices, thereby eliminating unintended interactions between devices while maintaining full transmission control capability
Solution Approach 2:
The operation lever serves multiple functions by being rotatable about two different rotation shafts. The same lever can perform both first-direction rotation operations and second-direction rotation operations, making it a universal control device that replaces multiple specialized shift levers while maintaining the ability to switch transmission states effectively
2Stability of the object's composition
If the operation tool is held at the desired shift position, then the transmission state is maintained, but unintended interactions occur when switching based on another shift operation device
Solution Approach 1:
The patent incorporates switch portions that detect the rotation positions of the operation lever and provide feedback signals to the transmission control system. This feedback mechanism ensures that the transmission state accurately reflects the operator's intentions while preventing unintended state changes, as the system only responds to detected lever positions rather than maintaining states based on physical lever positioning alone
Solution Approach 2:
The patent introduces switch portions as intermediary detection devices between the operation lever and the transmission control system. These switches detect lever rotation positions and translate them into control signals, acting as mediators that prevent direct mechanical interactions between multiple operation devices while maintaining stable transmission state control through electrical signal coordination
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
Enhances operability by simplifying the switching process between transmission states, reducing the risk of unintended interactions and maintaining the lever in desired positions, thus improving user experience and device efficiency.
Implementation Method 1
an urging portion that urges the operation lever to move to a predetermined initial position
Data Source
Figure 1
Figure 2
Figure 3
AI summary
An operation device (100) capable of switching operation of a transmission (7) of a work vehicle (1) includes an operation lever (130) that is rotatable in a first rotation direction about a first rotation shaft (144) and rotatable in a second rotation direction about a second rotation shaft (143) non-parallel to the first rotation shaft (144), an urging portion (136) that urges the operation lever (130) to move to a predetermined initial position, a first cam portion (170) that rotates following a rotation of the operation lever (130) in the first rotation direction, a second cam portion (150) that rotates following a rotation of the operation lever (130) in the second rotation direction, a first switch portion (190) that is pressed by the first cam portion (170) and detects the pressing in a state where the first cam portion (170) is rotated to a predetermined position, and a second switch portion (200) that is pressed by the second cam portion (150) and detects the pressing in a state where the second cam portion (150) is rotated to a predetermined position. The operation lever (130) is movable to a plurality of operation positions, the operation device (100) further includes a movement holding portion (133) (136) (181) that moves the operation lever (130) to the initial position when the operation lever (130) is positioned at a first operation position among the plurality of operation positions and holds the operation lever (130) in a state where the operation lever (130) is positioned at a second operation position when the operation lever (130) is positioned at the second operation position. The movement holding portion (133) (136) (181) includes an extendable portion (133) that is provided on the operation lever (130) and is expandable, and a recess (181) that receives a tip portion of the extendable portion (133) in an extension direction. The urging portion (136) urges the extendable portion (133) to extend such that the tip portion in the extension direction abuts on the recess (181). The recess (181) includes a first inclined portion (183a) that guides the extendable portion (133) such that the operation lever (130) positioned at the first operation position is moved to the initial position, and a second inclined portion (184a) that guides the extendable portion (133) such that the operation lever (130) positioned at the second operation position is held at the second operation position.