Vehicle Differential Helical Spline Control of Limiting Force
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Solution Overview
Problem
Existing vehicle differentials struggle to adjust differential limiting force effectively during acceleration and deceleration, leading to inadequate travel performance and stability, particularly in rear-wheel-drive or all-wheel-drive vehicles.
Innovation Solution
A vehicle differential configuration that includes a differential limiting mechanism with friction plates and a pressing member, where the differential limiting force is adjusted by varying the force applied to the helical spline, allowing for increased or decreased friction force based on the vehicle's acceleration or deceleration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a helical spline is used in the differential mechanism, then the differential limiting force can be adjusted during acceleration and deceleration, but the counteraction force from the helical spline reduces the effectiveness of the differential limiting mechanism
Solution Approach 1:
A thrust bearing is introduced as an intermediary component between the helical spline and the side gear. This thrust bearing receives and isolates the counteraction force from the helical spline, preventing it from acting on the side gear and friction plates. Meanwhile, the pressing member continues to apply pressing force to the friction plates through the side gear, ensuring the differential limiting mechanism functions effectively without interference from the helical spline's counteraction force.
2Adaptability or versatility
If electronic control is used to adjust the differential limiting force, then the differential limiting force can be precisely controlled, but the configuration becomes complicated and costs increase
Solution Approach 1:
The differential mechanism utilizes the vehicle's own operational forces (acceleration and deceleration) to automatically adjust the differential limiting force. During acceleration, the helical spline generates a pressing force that increases the differential limiting force. During deceleration, the pressing force is reduced, allowing the differential limiting force to decrease. This self-adjusting mechanism eliminates the need for electronic sensors, control units, and actuators, thereby maintaining a simple mechanical configuration while achieving adaptive differential limiting force control.
3Device complexity
If the pressing member is directly connected to the side gear, then the structure is simplified, but the counteraction force from the helical spline interferes with the differential limiting mechanism
Solution Approach 1:
The connection between the pressing member and the side gear is segmented by introducing a thrust bearing as an intermediate component. This segmentation separates the force transmission path into two independent paths: one for the pressing force (from the pressing member through the side gear to the friction plates) and another for the counteraction force (from the helical spline to the thrust bearing). This segmentation allows the pressing member to be structurally connected to the side gear while preventing the counteraction force from interfering with the differential limiting mechanism.
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 configuration enables the differential limiting force to be adjusted dynamically during acceleration and deceleration, improving the vehicle's travel performance and stability by optimizing the load distribution on the rear wheels.
Implementation Method 1
an outer circumferential portion of the cylindrical section meshes with an inner circumferential portion of the pressing member via a helical spline
Implementation Method 2
a plurality of friction plates arranged on an opposite side to the pinion gear, with respect to each of the side gears, in the rotation axis direction
Data Source
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AI summary
To provide a differential capable of adjusting a differential limiting force with a simple configuration a vehicle differential includes: a pair of side gears (34) arranged in a differential case (31); a plurality of friction plates (43) arranged on an axially outer side of respective one of the side gears 34; and a pressing member (41) (42) that holds the plurality of friction plates (43) together with respective one of the side gears (34). Each of the side gears (34) has: a gear section (34a) that meshes with a pinion gear (33); and a cylindrical section (34b) that extends from a radially inner portion of the gear section (34a) toward an axially outer side. An outer circumferential portion of the cylindrical section (34b) meshes with an inner circumferential portion of the pressing member (41) (42) via a helical spline (45).