Differential Gear Abutment Structure for Off-Road Grip and Turning
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Solution Overview
Problem
Existing differential apparatuses face a trade-off between off-road performance and turning performance, as increasing the biasing force to expand the differential limiting characteristic increases traveling resistance and reduces turning ability.
Innovation Solution
A differential apparatus with planar portions orthogonal to the rotation axis and a biasing member applying abutment forces between these planar portions, allowing for adjustable differential limiting characteristics without excessive initial torque, thereby maintaining turning performance while improving off-road capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the biasing force of the pressing member is increased to expand the differential limiting characteristic range, then off-road performance is improved, but the traveling resistance increases and turning performance deteriorates
Solution Approach 1:
The pressing force is segmented into two independent sources: the biasing member provides a first abutment force, while the meshing reaction force between the pinion gear and side gear provides a second abutment force. This segmentation allows the differential limiting characteristic to be enhanced through the combined effect without requiring excessive initial biasing force, thereby maintaining turning performance while improving off-road capability.
Solution Approach 2:
The invention changes the parameter of abutment force by introducing a dual-force mechanism. Instead of relying solely on a large initial biasing force, the system utilizes the dynamic meshing reaction force between gears to supplement the abutment force. This parameter change enables the differential limiting characteristic to be expanded without proportionally increasing the traveling resistance, thus resolving the contradiction between off-road performance and turning performance.
2Reliability
If a large initial torque is applied to expand the differential limiting characteristic range, then the differential locking capability is improved, but the wheel idling increases and traveling resistance increases
Solution Approach 1:
The meshing reaction force between the pinion gear and side gear automatically provides part of the abutment force needed for differential limiting. This self-service mechanism means the system utilizes its own operational dynamics (the meshing forces that occur during normal operation) to contribute to the differential locking capability, reducing the need for excessive initial torque from the biasing member and thereby minimizing unnecessary traveling resistance and wheel idling.
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 stabilizes the differential limiting characteristic and reduces wheel idling, enhancing off-road performance without compromising turning ability by adjusting the abutment forces and utilizing orthogonal sliding surfaces.
Implementation Method 1
A pressing member formed of a conical spring washer is disposed axially between the differential case and the side gear. The pressing member presses the side gear toward the pinion gear such that backlash between the side gear and the pinion gear is zero.
Implementation Method 2
The pinion gear and each of the side gears are bevel gear sets. A meshing reaction force between the pinion gear and the side gear applies a second abutment force between the first planar portion and the second planar portion.
Data Source
AI summary
A differential apparatus includes a differential case, a pinion gear that is rotatably supported in the differential case and revolves as the differential case rotates, and side gears that respectively mesh with the pinion gear. The side gears are relatively rotatable with each other. A first planar portion orthogonal to a rotation axis is provided on a back side each of the side gears. A second planar portion which can abut against the first planar portion is provided in the differential case. A first abutment force is applied between the first planar portion and the second planar portion by a biasing member. A meshing reaction force between the pinion gear and the side gear applies a second abutment force between the first planar portion and the second planar portion.