Wheel Loader Steering Joystick with Backlash-Compensating Urging
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Solution Overview
Problem
Existing steering systems in articulated work machines suffer from backlash in transmission mechanisms, leading to looseness and deteriorated operation feeling due to the base member rotating with the joystick lever, which affects the operator's control precision and comfort.
Innovation Solution
A steering device with a movable section and an urging mechanism that adjusts the movement of the base member relative to the support section, using a spring member to counteract looseness and maintain precise control, combined with a controller to manage hydraulic pressure for improved operation feeling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a transmission mechanism is provided in the steering system, then the steering angle can be changed by controlling hydraulic actuator flow rate, but backlash occurs in gears and intermediate shafts causing the base member to become movable in the rotational direction
Solution Approach 1:
The urging mechanism applies a preliminary counteracting force to prevent the base member from moving due to backlash. The urging member (spring) continuously exerts force on the base member to maintain contact with the transmission mechanism, preventing the looseness that would otherwise occur during steering operations.
Solution Approach 2:
The system transitions from a static connection to a dynamic one where the base member can move relative to the movable section. This controlled movement allows the urging mechanism to maintain contact and eliminate backlash while still permitting necessary steering motions.
2Adaptability or versatility
If the base member is rotatably supported with respect to the movable section, then the base member can rotate in response to steering angle changes, but the base member becomes movable in the rotational direction due to backlash
Solution Approach 1:
The urging mechanism preemptively counteracts the loosening effect of backlash by continuously applying force to keep the base member engaged with the transmission mechanism, ensuring precise operation feeling while maintaining rotational adaptability.
Solution Approach 2:
The urging member acts as an intermediary between the base member and the movable section, mediating the interaction to eliminate gaps caused by backlash while allowing the base member to rotate in response to steering inputs.
3Reliability
If the joystick lever returns to a predetermined position due to base member rotation, then the steering angle change is stopped and maintained, but backlash causes looseness during this return movement
Solution Approach 1:
The urging mechanism continuously applies force to prevent the base member from developing looseness during the return movement of the joystick lever, ensuring smooth and precise operation feeling while maintaining reliable steering angle positioning.
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
The solution enhances the operation feeling by reducing looseness and improving control precision, ensuring smoother and more responsive steering operations.
Implementation Method 1
an urging mechanism that adjusts a movement of the base member with respect to the movable section
Data Source
AI summary
A wheel loader includes a vehicle body frame, a transmission mechanism, a support section, a movable section, a joystick lever, and an urging mechanism. The transmission mechanism transmits a movement of the vehicle body frame. The support section is fixed with respect to the vehicle body frame. The movable section is connected to the transmission mechanism and is movably supported by the support section. The movement of the vehicle body frame is input to the movable section. The joystick lever accepts an operation to move with respect to the movable section by the operation. The urging mechanism adjusts a movement of the movable section with respect to the support section.