Multi-Piston Power Transmission Device Torque and Thermal Management
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Solution Overview
Problem
Conventional power transmission devices for agricultural and industrial machinery face challenges in increasing torque capacity, thermal capacity, and durability while maintaining manufacturing efficiency and reducing costs, particularly due to limitations in piston design and return spring force determination.
Innovation Solution
A power transmission device with a housing that connects a clutch housing, clutch hub, and disk housing, featuring multiple pistons with increased friction disk sizes and a return spring system optimized to distribute axial force effectively, enhancing torque transmission and thermal management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the area of friction disks is increased to improve torque capacity, then torque capacity is improved, but the mass of core plate increases, thereby increasing thermal capacity
Solution Approach 1:
The patent transitions from a single piston to a multi-piston arrangement (two or more pistons), changing the dimensional configuration of the force application system. This allows the friction disk area to be increased for higher torque capacity while the increased mass of core plate is compensated by the distributed force from multiple pistons, effectively resolving the contradiction between torque capacity and thermal capacity management.
2Force
If two or more pistons are mounted in one power transmission device to increase axial force, then axial force is increased, but the determination of return spring force becomes more difficult
Solution Approach 1:
The patent merges multiple pistons (two or more) into a single power transmission device, combining their axial forces to achieve higher total axial force. The return spring system is designed to counterbalance the combined axial force from all pistons simultaneously, simplifying the force determination through unified spring loading rather than requiring separate determination for each piston.
Solution Approach 2:
The patent changes the parameter configuration by using multiple pistons with potentially different areas, allowing the return spring force to be optimized for the combined axial force. The hydraulic pressure can be distributed across multiple piston chambers, and the return spring force is determined based on the total axial force requirement, simplifying the overall force balance equation.
3Power
If the axial force applied to pistons is increased to improve torque capacity, then torque capacity is improved, but the pressure applied onto friction disks increases, reducing their lifespan
Solution Approach 1:
The patent segments the axial force application by using two or more pistons instead of one large piston. This segmentation distributes the total axial force across multiple friction disk interfaces, reducing the pressure concentration on any single friction disk while maintaining the total torque capacity. The friction disks experience lower individual pressure loads, extending their operational lifespan.
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 increases torque capacity, improves thermal capacity, and extends the lifespan of friction materials while simplifying manufacturing processes and reducing costs by optimizing the design of the power transmission device.
Implementation Method 1
If an operating hydraulic pressure is supplied into the piston chamber 220, the piston 230 can move in the housing in an axial direction
Implementation Method 2
the piston 230 moves to one side in the axial direction and frictionally couples the first friction disk 250 and the second friction disk 252
Implementation Method 3
the return spring 240 exerts a spring load counteracting against an axial force generated by the operating hydraulic pressure on the piston 230
Data Source
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AI summary
The present invention relates to a power transmission device including two or more pistons. The power transmission device may include: a housing arranged to form a mounting space by connecting a clutch housing, a clutch connecting portion, a clutch hub and a disk housing to each other; a power transmission hub selectively and operably connected to the housing; a plurality of first friction disks splined to an interior circumference of the disk housing; a plurality of second friction disks splined to an exterior circumference of the power transmission hub and disposed alternately with the first friction disks; a piston module including two or more pistons, each of which has a corresponding piston chamber, and selectively and frictionally coupling the first friction disks with the second friction disks by an operating hydraulic pressure supplied to the piston chambers; and at least one return spring or at least one separating spring supplying a spring load counteracting against an axial force generated by the operating hydraulic pressure, and disposed at an inside or an outside of the piston module, wherein friction material is attached to any one surface or both surfaces of each first friction disk or each second friction disk.