Conical Motor Chamber Pump Unit for Lower Hydraulic Friction
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Solution Overview
Problem
Existing compact pump units do not provide sufficient pump capacity in certain applications, necessitating a design that balances compactness with increased capacity.
Innovation Solution
A pump unit design featuring a diverging clearance between the motor rotor and motor housing, with a fluid outlet at the large diameter, reduces hydraulic friction by forcing hydraulic fluid to exit the motor chamber, allowing for a more compact configuration while maintaining pump capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a compact pump unit configuration is used with integrated motor rotor and pump rotor, then the device size is reduced, but the pump capacity becomes insufficient for certain applications
Solution Approach 1:
The invention changes the geometric parameters of the clearance between motor rotor and pump rotor by introducing a conical surface. The clearance varies radially, being smaller at the large diameter end and larger at the small diameter end, which optimizes fluid flow characteristics and reduces friction losses, thereby improving pump capacity without increasing device volume
2Reliability
If hydraulic fluid is present in the clearance between motor rotor and motor housing, then lubrication is provided, but hydraulic friction increases reducing available power
Solution Approach 1:
The invention applies local quality by creating a non-uniform clearance distribution through the conical surface. The clearance is locally smaller at the large diameter end and larger at the small diameter end, which directs fluid flow in a specific pattern that reduces hydraulic friction while maintaining necessary lubrication in critical areas
3Ease of manufacture
If the clearance between motor rotor and motor housing is uniform, then manufacturing is simplified, but hydraulic fluid flow is not optimized reducing power transfer efficiency
Solution Approach 1:
The invention introduces asymmetry by replacing the uniform clearance with a conical clearance profile. The clearance varies radially along the axial direction, creating an asymmetric fluid flow path that optimizes power transfer efficiency by reducing hydraulic friction, while the conical geometry remains manufacturable using standard machining processes
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 reduces hydraulic friction, increasing power transfer efficiency and enabling a smaller electric motor to achieve the same pump capacity, resulting in a more compact and powerful pump unit.
Implementation Method 1
The clearance diverges from a small diameter to a large diameter. The divergence of the clearance means that a clearance volume differs in axial position. Seen in the axial direction, the diverging shape of the clearance causes a pressure difference between a position of the small diameter and a position of the large diameter of the clearance. Due to the diverging shape of the clearance and the presence of the fluid outlet, hydraulic fluid in the motor chamber is forced to flow from the small diameter to the large diameter of the clearance.
Implementation Method 2
The divergence of the clearance means that a clearance volume differs in axial position. Seen in the axial direction, the diverging shape of the clearance causes a pressure difference between a position of the small diameter and a position of the large diameter of the clearance.
Implementation Method 3
The electric motor comprises a motor rotor. The motor rotor comprises a motor rotor body. The motor rotor body is driveable in rotation. Further, the electric motor comprises a plurality of field coils and a plurality of magnets. The magnets are disposed opposite the field coils. Preferably, the electric motor is a brushless DC motor in which the field coils are arranged stationary and the magnets are connected to the motor rotor body.
Data Source
AI summary
Pump unit (10) comprising an electrically driven hydraulic pump (4) for pressurising a hydraulic actuating system. The pump unit (10) comprises a hydraulic pump (4) in pump chamber (110) of a pump housing (11). The pump (4) is driven by an electric motor (3) which includes a motor rotor body (310) and an assembly of field coils (32) and magnets (33). A clearance (C) is provided around the motor rotor body (310) which is diverging in the axial direction from a small to a large diameter, such that a rotation of the motor rotor body (310) forces hydraulic fluid to flow towards the larger diameter. The fluid outlet (122) at the larger diameter of the clearance allows an exit of the hydraulic fluid, such that a fluid flow is generated which reduces hydraulic friction inside the pump unit to render an increase in pump capacity.