Controlled Differential With Compound Planetary Gear Set
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Solution Overview
Problem
Existing differential mechanisms for vehicular drive systems, particularly in skid-steered vehicles, fail to effectively control relative speeds between shafts, leading to inefficiencies in steering and torque distribution, especially in applications like battle tanks and bulldozers where precise control is crucial.
Innovation Solution
A controlled differential mechanism using a compound planetary gear set with unequal gear tooth ratios between ring gears and planet gears, coupled with a rotatable planet carrier, allows for variable speed differences between shafts, enabling precise steering control by adjusting the planet carrier's rotation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a conventional differential mechanism is used, then the structure is simple, but the control precision of relative speeds between shafts is insufficient
Solution Approach 1:
The differential mechanism is segmented into multiple planetary gear sets with different gear ratios, allowing independent control of speed differences between shafts. Each planetary gear set handles a specific speed ratio, enabling precise control without requiring a single complex mechanism.
Solution Approach 2:
The invention uses a rotatable planet carrier that can dynamically adjust its position to vary the effective gear ratio. This dynamic adjustment capability allows the differential to precisely control speed differences between shafts by rotating the planet carrier to different angular positions, transforming a static gear system into a dynamically adjustable one.
2Productivity
If a conventional differential mechanism is used, then the device is easy to manufacture, but the steering control efficiency is insufficient
Solution Approach 1:
The rotatable planet carrier enables dynamic adjustment of speed differences during steering operations, allowing the differential to optimize torque distribution and steering response in real-time. This dynamic capability significantly improves steering control efficiency compared to fixed-ratio differentials.
Solution Approach 2:
The invention changes the effective gear ratio parameter by rotating the planet carrier to different positions. This parameter change allows the differential to adapt to varying steering conditions, improving control efficiency without requiring multiple separate mechanisms for different operating conditions.
3Measurement precision
If unequal gear ratios are used in planetary gears, then the speed difference control is precise, but the torque distribution becomes complex
Solution Approach 1:
The invention deliberately uses asymmetric (unequal) gear ratios in the planetary gear sets to achieve precise speed difference control. The asymmetric design allows one shaft to rotate at a different speed than the other, providing precise control over speed differences while the rotatable planet carrier manages the torque distribution complexity.
Solution Approach 2:
The rotatable planet carrier acts as an intermediary element that mediates between the unequal gear ratios and the output shafts. By adjusting the carrier's position, it balances the torque distribution caused by the unequal ratios, allowing precise speed control without unmanageable torque complexity.
4Adaptability or versatility
If the planet carrier is made rotatable, then the speed difference variation is controllable, but the device complexity increases
Solution Approach 1:
Making the planet carrier rotatable transforms the differential from a static to a dynamic system. The carrier can now be rotated to different angular positions to vary the effective gear ratio and control speed differences between shafts, providing adaptability for different operating conditions.
Solution Approach 2:
The rotatable planet carrier serves multiple functions: it supports the planetary gears, transmits torque, and acts as a control element for varying speed differences. This multi-functionality reduces the need for separate control mechanisms, limiting the increase in overall device complexity despite the added rotational capability.
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 solution provides a precise and efficient means of controlling speed differences between shafts, enhancing steering capabilities and torque distribution, allowing for improved maneuverability and stability in skid-steered vehicles by compensating for inherent speed differences through gear ratio adjustments and planet carrier rotation.
Implementation Method 1
a compound planetary gear set comprising one or more compound planet gears and a common planet carrier, a first planet gear of the or each said compound planet being in mesh with the first ring gear and a second planet gear of the or each said compound planet being in mesh with the second ring gear
Data Source
AI summary
A controlled differential, particularly for exercising steering control of skid steered vehicles, having a compound planetary gear set coupling two shafts. Respective ring gears turn with the shafts and mesh with a compound planet gear in a planet carrier, the ratios of the number of gear teeth between each ring gear and the respective gear of the compound planet being unequal so that when the planet carrier is stationary the two shafts are coupled through the differential to turn together in the same sense but with a speed difference, and controlled rotation of the planet carrier varies the speed difference between the shafts in accordance with the sense and speed of rotation of the planet carrier.