Cooling Ring Spray Layout for Uniform Coil Cooling in Electric Machines
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Solution Overview
Problem
Existing rotating electrical machines face inefficiencies in uniformly spraying cooling fluid onto the coils due to insufficient inlet pressure, leading to uneven cooling.
Innovation Solution
A rotating electrical machine with a hollow cooling ring having an inclined outlet orifice that projects cooling fluid obliquely onto the coils, combined with radial orifices in the shaft for parallel cooling, ensuring effective cooling despite low inlet pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If cooling fluid is sprayed through radial orifices in the shaft, then the coils can be cooled, but the insufficient inlet pressure prevents uniform and effective spraying around the entire circumference
Solution Approach 1:
The invention introduces a new spatial dimension by adding inclined outlet orifices that spray cooling fluid at an angle (e.g., 45 degrees) relative to the shaft axis, rather than purely radially. This angular dimension allows the cooling fluid to reach the coil ends more effectively despite low pressure, as the oblique trajectory extends the fluid's reach toward the coil surfaces that are positioned axially outward.
Solution Approach 2:
The invention applies different spraying characteristics to different regions: radial orifices continue to provide circumferential coverage, while newly added inclined orifices specifically target the coil ends where cooling is most critical. This localized quality enhancement ensures that the most heat-prone areas (coil ends) receive focused cooling attention regardless of overall pressure limitations.
2Productivity
If cooling fluid pressure is increased to improve spraying effectiveness, then cooling efficiency improves, but the system becomes more complex and requires higher pressure components
Solution Approach 1:
The invention changes the spray parameter from purely radial direction to include an angular component (e.g., 45-degree inclination). This parameter modification allows the existing low-pressure cooling fluid to achieve better cooling effectiveness by altering the spray trajectory, thereby improving cooling efficiency without increasing system pressure or complexity.
3Area of stationary object
If the cooling fluid is sprayed radially onto the coils, then the cooling coverage can be maximized, but the coil ends remain inadequately cooled due to pressure loss
Solution Approach 1:
By introducing inclined outlet orifices that spray at an angle to the shaft axis, the invention adds a dimensional component to the spray trajectory. This angular dimension enables the cooling fluid to reach the coil ends (which extend axially) more effectively, thereby expanding the cooled surface area without requiring higher pressure.
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 achieves uniform and efficient cooling of the coils and rotor by targeting the cooling fluid directly onto them, even with low inlet pressure, enhancing cooling efficiency.
Implementation Method 1
a chamfered annular wall in which at least one first outlet orifice is provided for projecting the cooling fluid onto the coil ends in a direction inclined relative to the axial direction
Implementation Method 2
a cooling circuit comprising a fluid supply arranged in the casing and configured to convey a cooling fluid
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
Rotating electrical machine (1) comprising: - a stator (2) comprising a winding (7) forming coils (7a, 7b) at the axial ends, the stator (2) being integral with a casing (5) of the rotating electrical machine (1), the casing (5) comprising at least one bearing (6), - a rotor (3) integral with a shaft (4) of said machine (1), - a cooling circuit comprising a fluid supply (12) arranged in the casing (5) and a hollow cooling ring (15) fixed to the casing (5) and having an inlet (16) fluidly communicating with the fluid supply (12) and a chamfered annular wall (17) in which at least one first outlet orifice (18) is arranged to project the cooling fluid onto the coils (7a) of the winding (7) in a direction inclined relative to the axial direction.