Planetary Power Take Off Device with Integral Gear Set
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Solution Overview
Problem
Conventional power take off devices face challenges in providing multiple speed ratios and achieving large speed reduction gear ratios while maintaining a compact size, which is essential for applications like blower propulsion and winch operation, where varying torque and speed are required.
Innovation Solution
A power take off device with an integral planetary gear set and multiple clutches that allows for single, two, or three speed operations, featuring a sun gear, planet gears, and a ring gear in a unitary structure, enabling speed ratio changes without stopping the rotational movement, and a compact design with the input and output shafts sharing the same longitudinal axis, along with a clutch/brake unit for fluid pressure actuation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a large speed reduction gear ratio is provided in conventional power take off devices, then torque increase is achieved, but the device size becomes large and cannot be compact
Solution Approach 1:
The patent applies nesting by placing the planetary gear set inside the housing with the input shaft, allowing multiple gear reduction stages to be compactly arranged. The planet gears are nested around the sun gear, and the ring gear encloses the entire planetary mechanism, achieving a large overall speed reduction ratio within a small volume.
Solution Approach 2:
The patent uses axial arrangement of multiple planetary gear sets along the input shaft axis to achieve large speed reduction ratios. By stacking gear sets in the axial dimension rather than requiring large radial dimensions, the device maintains a compact footprint while achieving the required torque multiplication.
2Adaptability or versatility
If a single constant speed ratio is provided, then the device structure is simple, but it cannot provide varying torque and speed for different operational phases
Solution Approach 1:
The patent makes the speed ratio dynamic by incorporating clutches that can selectively engage different planetary gear sets or different paths through the gear sets. This allows the device to switch between multiple speed ratios during operation, adapting to different torque and speed requirements without changing the physical structure.
Solution Approach 2:
The patent divides the planetary gear system into multiple independent planetary gear sets or stages, each providing a specific reduction ratio. By segmenting the overall reduction into multiple stages with selectable engagement, the device can provide variable speed ratios while keeping each individual gear set relatively simple in structure.
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 provides a versatile power take off device capable of multiple speed operations, reducing stress on clutches and achieving a wide range of speed and torque outputs, suitable for various applications with a compact footprint, by utilizing a planetary gear set and clutch/brake units for efficient power transmission.
Implementation Method 1
a planetary gear set including a sun gear, a carrier with associated planet gears, and a ring gear
Implementation Method 2
a clutch/brake unit for fluid pressure actuation
Data Source
AI summary
A power take off device includes input and output shafts and an integral planetary gear set. The power take off device may be a single speed or a multi-speed device. The input shaft and the output shaft are mechanically connected through the planetary gear set. The output shaft may be driven in a forward direction and/or may be driven in a reverse direction. For example, the output shaft may be driven with a speed reduction, a speed increase, or at a 1:1 ratio with the input shaft.