Friction Drive Pump for Transfer Cases
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Solution Overview
Problem
Gerotor pumps in transmissions and transfer cases lack the ability to be selectively deactivated, leading to unnecessary pumping actions that reduce efficiency by constantly driving the outer gerotor, even when a pumping action is not needed.
Innovation Solution
A friction drive pump assembly with a selectively engageable pumping device mounted on a rotatable shaft, utilizing a clutch assembly and Belleville Spring to control the rotational force transfer, allowing the pump to be activated only when necessary, thereby reducing unnecessary pumping actions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the inner gerotor is mounted on the shaft through a spline connection, then the pump can continuously transfer rotational force, but the pump cannot be deactivated and constantly drives the outer gerotor even when pumping is not needed
Solution Approach 1:
The patent applies the dynamics principle by making the connection between the inner gerotor and shaft conditional rather than permanent. The friction drive clutch allows the inner gerotor to be dynamically engaged or disengaged from the shaft based on system needs, enabling the pump to be activated or deactivated as required. This resolves the contradiction by allowing continuous rotational force transfer when needed while enabling deactivation when pumping is not required.
Solution Approach 2:
The patent segments the rotational force transfer mechanism into distinct engageable and disengageable components. The friction drive clutch acts as a separable interface between the shaft and inner gerotor, allowing independent control of the pumping function. This segmentation enables the system to maintain reliability through available engagement while eliminating energy loss through controlled disengagement.
2Power
If the pump is constantly active, then rotational force is continuously transferred, but transmission or transfer case efficiency is reduced
Solution Approach 1:
The friction drive clutch enables dynamic control of power transfer, allowing the system to optimize between maintaining sufficient rotational force transfer capability and maximizing transmission efficiency by disengaging the pump when its output is not needed.
Solution Approach 2:
The patent changes the operational parameter of the pump from constant engagement to variable engagement. The friction drive clutch allows adjustment of the torque transfer parameter, enabling full power transfer when pumping is needed and zero or minimal power transfer when it is not, thereby improving overall system productivity and efficiency.
3Loss of energy
If a friction drive clutch is used to selectively engage the pump, then the pump can be deactivated when not needed, but the device complexity increases
Solution Approach 1:
The friction drive clutch serves as an intermediary component between the shaft and inner gerotor. This mediator enables selective engagement and disengagement, reducing pumping losses when the pump is not needed. While it does increase device complexity, the clutch is a well-established component that provides a practical solution to the energy loss problem.
Solution Approach 2:
The patent replaces the traditional spline connection mechanical system with a friction drive clutch system. This substitution allows for selective engagement through friction-based torque transfer rather than permanent mechanical coupling, enabling the pump to be deactivated when not needed despite the increased complexity of the clutch mechanism.
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 enables the pump to be activated only when needed, reducing pumping losses and improving efficiency by minimizing torque requirements, resulting in increased fuel economy and reduced energy consumption.
Implementation Method 1
a friction drive clutch assembly which includes a friction drive sleeve that is pressed against a shoulder on the shaft
Implementation Method 2
The friction drive clutch assembly may include a Belleville Spring
Data Source
AI summary
A pump having an actuator mounted on a rotatable shaft, and a pump mounted on the shaft, which is selectively engageable with the actuator. When the actuator is actuated, the pump will receive rotational force from the shaft, creating a pumping. action.