Hydrostatic Variator Module for Continuous Speed Adjustment
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Solution Overview
Problem
Existing power divider systems between internal combustion engines and vehicle transmissions are unable to adjust output shaft speed in a continuously variable manner at constant input speed, especially at low vehicle speeds and high engine speeds, often requiring slipping clutches or reduced engine speed, which limits their effectiveness in applications like fire trucks and other heavy-duty vehicles.
Innovation Solution
A module comprising a summing planetary gear set and a variator unit is installed between the input shaft of an internal combustion engine and the output shaft of a conventional transmission, allowing for continuous variable adjustment of angular momentum and enabling independent adjustment of vehicle drive and power take-off speeds, eliminating the need for slipping clutches by using a hydraulic or electric variator system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If slipping clutches are used to adjust output shaft speed at low vehicle speeds, then vehicle speed can be reduced, but energy loss increases and clutch wear occurs
Solution Approach 1:
The patent replaces the mechanical slipping clutch system with a hydrostatic variator system that uses hydraulic fluid to transmit and adjust power. The variator continuously varies the output speed by changing the hydraulic coupling between input and output shafts, eliminating the need for mechanical slip and associated energy losses.
Solution Approach 2:
The invention employs a hydrostatic variator that utilizes hydraulic pressure and fluid dynamics to achieve continuous speed adjustment. The variator uses variable displacement pumps and motors to transfer power with minimal loss, allowing smooth speed control without the energy dissipation inherent in mechanical clutch slipping.
2Speed
If engine speed is reduced to achieve low vehicle speeds, then clutch slipping is avoided, but power take-off performance decreases
Solution Approach 1:
The patent segments the power transmission path into independent controllable sections using the variator system. The input shaft receives power from the engine at high speed, the variator independently adjusts the output shaft speed to low values for vehicle movement, while simultaneously providing controlled power to auxiliary units through the same input shaft, allowing both functions to operate at optimal speeds independently.
Solution Approach 2:
The variator system serves multiple functions simultaneously: it reduces output shaft speed for vehicle propulsion while maintaining high engine speed for optimal power generation, and also enables independent power delivery to auxiliary units. This multi-functional capability resolves the contradiction between vehicle speed reduction and power take-off performance.
3Device complexity
If a fixed ratio transmission is used, then the structure is simple, but the output speed cannot be adjusted independently of engine speed
Solution Approach 1:
The patent replaces fixed ratio gears with a dynamic hydrostatic variator system that continuously adjusts the transmission ratio based on operational requirements. The variator's variable displacement mechanism allows smooth, stepless adjustment of output speed while maintaining a relatively compact structure, achieving adaptability without excessive complexity.
4Speed
If a torque converter is used to enable low speed operation, then vehicle speed can be reduced, but the system becomes more complex and costly
Solution Approach 1:
The patent combines the speed adjustment function and power distribution function into a single integrated variator system. This merged system simultaneously achieves continuous speed variation for vehicle propulsion and independent power delivery to auxiliary units, replacing what would otherwise require separate torque converters and clutch systems, thereby reducing overall complexity despite the advanced functionality.
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 allows vehicles to operate at high engine speeds while maintaining low travel speeds without clutch slipping, providing optimal speed adjustment for both vehicle drive and power take-offs, enhancing efficiency and power transmission capabilities, and enabling retrofitting of existing vehicles with conventional transmissions.
Implementation Method 1
a summing planetary gear set (17) with a ring gear (18) which is coupled via a spur-gear stage (16) with the transmission input shaft (1), with a planet carrier (21) which is coupled with the transmission output shaft (3), and with a sun wheel (19) which is driven by way of a variator system (13)
Implementation Method 2
the speed of the sun wheel (19) being adjustable in a continuously variable manner by a variator system (13)
Data Source
AI summary
The present invention relates to a device for a transmission, comprising a summing planetary gear set (17) and a variator unit (13) and components that bring them into operative connection with each other and with an input shaft (1) and output shaft (3, 8) for influencing the output speed in a continuously variable manner at constant input speed. The device can be installed as a prefabricated module between an internal combustion engine and a conventional transmission of any configuration and is also suitable for splitting the drive power of an internal combustion engine among a vehicle drive and one or several power take-offs, with the speed of the vehicle drive and/or the speed of the power take-off being adjustable in a continuously variable manner by the device. The device is also suitable for retrofitting existing motor vehicles.