Shared Ring Gear Transmission Assembly for Smooth Gear Shifts
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Solution Overview
Problem
Existing transmission assemblies for working machines, such as articulated haulers, fail to provide smooth gear shifts and are limited in their compactness and energy efficiency, particularly in their application within the powertrain of construction equipment.
Innovation Solution
A transmission assembly featuring a common ring gear, sun gears, planet carriers, and locking mechanisms controlled by fluid pressure, allowing for efficient gear changes and compact design, with optional use as a parking brake without requiring a fluid pressure source.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a conventional transmission assembly is used, then the structure is relatively simple, but the gear shifts are not smooth and the compactness is limited
Solution Approach 1:
The patent combines two planetary gear sets into a single integrated transmission assembly with a common ring gear, sun gears, and planet carriers. This merging of components enables smooth gear shifts through coordinated locking and releasing of planet carriers while maintaining a compact structure that does not significantly increase overall complexity.
Solution Approach 2:
The transmission assembly employs dynamic locking and releasing mechanisms that can quickly transition between different gear conditions. The system uses controllable locking elements to dynamically engage or disengage planet carriers, enabling smooth and rapid gear shifts without requiring complex multi-stage transmission designs.
2Volume of moving object
If the transmission assembly is made more compact, then the space efficiency improves, but the gear shift mechanism becomes more complex
Solution Approach 1:
The transmission assembly adopts a nested planetary gear configuration where planet gears are positioned within the ring gear, and multiple planetary gear sets share common components. This nesting arrangement achieves high compactness and space efficiency while the locking mechanisms are integrated into the existing structure rather than added as separate external components.
Solution Approach 2:
The locking mechanisms serve multiple functions: they enable gear shifts by selectively locking planet carriers, provide parking brake capability by locking the ring gear, and can operate in both locked and released states. This multi-functionality reduces the need for separate dedicated components, maintaining compactness while achieving complex operational requirements.
3Reliability
If a fluid pressure source is continuously operated to maintain the parking brake, then the braking function is reliable, but the energy consumption increases
Solution Approach 1:
The parking brake mechanism uses a spring-loaded locking element that automatically engages with the ring gear when fluid pressure is reduced or removed. The spring force maintains the locked position without requiring continuous energy input, while the system can be released by applying fluid pressure to overcome the spring force. This self-sustaining mechanism ensures reliable parking brake function while eliminating continuous energy consumption.
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
Enables fast, smooth gear changes with a compact and energy-efficient transmission assembly, suitable for use in working machines, and allows for stationary operation of the common ring gear without a fluid pressure source, enhancing maintenance and reducing energy consumption.
Implementation Method 1
a first locking mechanism being adapted to be controlled by a first fluid pressure conducted to the first locking mechanism such that: for at least a first fluid pressure equal to zero overpressure, the first locking mechanism is adapted to assume a locked condition
Implementation Method 2
the first locking mechanism comprises a first biasing member, preferably a first spring arrangement, adapted to bias the first locking mechanism so as to assume the locked condition
Data Source
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AI summary
The present invention relates to a transmission assembly (38) comprising a common ring gear assembly (46), a first sun gear (48), a first planet carrier (50) carrying a set of planet gears (52), a second sun gear (54) and a second planet carrier (56) carrying a set of planet gears (58). The set of planet gears (52, 58) of each one of the first and second planet carriers (50, 56) meshing with the common ring gear assembly (46). The set of planet gears of the first planet carrier (50) meshing with the first sun gear (48) and the set of planet gears of the second planet carrier (56) meshing with the second sun gear (54). The transmission assembly (38) further comprises a transmission housing (60). The transmission assembly (38) is configured such that: - the second sun gear (54) is adapted to be connected to a transmission input shaft (40); - the common ring gear assembly (46) is adapted to be connected to a transmission output shaft (42), and - the second planet carrier (56) and the first sun gear (48) are operatively connected to each other.