Differential Gear Braking Device Nested Planetary Unit
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Solution Overview
Problem
Existing differential gears are structurally complex, heavy, and expensive due to the placement of braking devices far from the planetary unit, requiring complex bearings and increased installation space, which complicates control and increases mass to be accelerated and braked.
Innovation Solution
The braking device is positioned on both sides of the planetary gear pairs, allowing direct application of braking force and torque to the planetary unit, eliminating the need for a complex axial bearing and reducing the overall size and weight of the differential gear, using friction plates with a high power-to-weight ratio for efficient torque transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the braking device is positioned far from the planetary unit, then the braking torque can be applied to the planetary unit, but the structural complexity increases and the device becomes larger and heavier
Solution Approach 1:
The braking device is nested within the planetary unit structure itself, with friction plates integrated into the planetary carrier and planet gears. This eliminates the need for separate external braking components and complex transmission mechanisms, directly resolving the contradiction by applying braking torque at the source without increasing structural complexity
Solution Approach 2:
Friction plates serve as intermediaries between the braking force and the planetary unit components. These friction plates are strategically positioned to directly contact planet gears or the planetary carrier, enabling efficient torque transmission without requiring complex mechanical linkages or distant positioning
2Power
If the braking device is positioned far from the planetary unit, then the braking torque can be applied, but the installation space requirements increase
Solution Approach 1:
The braking components are nested within the existing planetary unit footprint, utilizing the internal space of the differential housing. Friction plates are positioned between existing components rather than adding external bulk, maintaining a compact overall package while enabling effective braking torque application
Solution Approach 2:
The braking mechanism utilizes the axial dimension within the planetary unit rather than requiring radial or longitudinal extension. By positioning friction plates axially between the planetary carrier and housing, or between planet gears, the design achieves effective braking without increasing the external dimensions of the differential assembly
3Power
If the braking device is positioned far from the planetary unit, then the braking torque can be applied, but the mass to be accelerated and braked increases
Solution Approach 1:
The essential braking function is extracted from a complex external mechanism and concentrated into minimal friction plates integrated with the planetary unit. This removes unnecessary mass from the system while preserving the braking capability, directly addressing the contradiction between power application and weight reduction
Solution Approach 2:
Simple friction plates replace complex, heavy braking mechanisms. These lightweight friction plates are designed to be replaced rather than repaired, prioritizing weight reduction and simplicity over long-term durability. The plates are inexpensive and can be easily replaced, making the system lighter overall while maintaining functional effectiveness
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 results in a compact, lightweight, and cost-effective differential gear with improved control and monitoring capabilities, reduced installation space requirements, and enhanced stability, enabling precise and efficient interventions in vehicle dynamics.
Implementation Method 1
The braking device has friction plates (15) on both sides of the planetary unit (5), which can be compressed by a hydraulic unit (17)
Data Source
Figure 1~2
Figure 3~5
AI summary
The invention relates to a differential gear for a motor vehicle, the drive cage and the output shafts being coupled by means of a switchable intermediate gear such that an acceleration of an output shaft relative to the drive shaft speed is possible. A yaw moment can thus be generated and used for influencing the handling characteristics, or for corrective intervention in critical driving situations as an Active-Yaw" differential. The intermediate gear comprises a planetary unit with planet gear pairs which may be braked with relation to a fixed gear housing by a braking device for generation of the yaw moment. According to the invention, the braking device acts to both sides and at least partly against the planet gear pairs. With relation to the state of the art, advantages of compactness, controllability, weight and production are achieved by the above and further construction simplifications.