Motor Liquid Cooling Bulkhead With Circumferential Nozzle Holes

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing liquid cooling structures for motors, such as those used in automobiles and construction machines, often experience uneven cooling performance along the axial direction due to concentrated coolant ejection, leading to suboptimal operation characteristics.

Innovation Solution

A liquid cooling structure featuring a cylindrical casing with an annular end plate, a stator with annular teeth and wound coils, and a bulkhead with nozzle holes arranged circumferentially to uniformly distribute coolant across the motor, ensuring consistent cooling performance by varying the flow path width and nozzle geometry.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If coolant is ejected in a concentrated manner onto one end of the motor, then cooling performance at that location is improved, but temperature uniformity between opposite ends deteriorates

Engineering Contradiction:
Improvecooling performanceVSAvoidtemperature uniformity
Core Design Contradiction:
TemperatureVSStability of the object's composition

Solution Approach 1:

The bulkhead is divided into multiple segments in the circumferential direction, with each segment containing nozzle hole portions. This segmentation allows coolant to be ejected at multiple locations around the stator core, distributing cooling across both ends of the motor rather than concentrating it at one location, thereby achieving uniform temperature distribution while maintaining effective cooling.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Nozzle hole portions are specifically positioned at locations corresponding to coil ends where heat generation is concentrated. The local cooling quality is enhanced at these critical heat-producing areas while also extending cooling coverage to both ends of the motor through the segmented bulkhead design, resolving the contradiction between targeted cooling and uniform temperature distribution.

Inventive Principle:
Principle #3Local quality

2Area of stationary object

If nozzle hole portions are arranged over entire circumference of bulkhead, then cooling coverage is improved, but device complexity increases

Engineering Contradiction:
Improvecooling coverageVSAvoidstructure complexity
Core Design Contradiction:
Area of stationary objectVSDevice complexity

Solution Approach 1:

The bulkhead is segmented into multiple sections in the circumferential direction, with nozzle hole portions distributed across these segments. This segmentation achieves comprehensive cooling coverage around the entire circumference of the stator core while maintaining a modular and manageable structural complexity that facilitates manufacturing and assembly.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The bulkhead serves multiple functions: it supports the stator core, provides structural integrity to the motor, and incorporates nozzle hole portions for coolant distribution. This multi-functionality reduces the need for separate cooling components, thereby achieving extensive cooling coverage without proportionally increasing device complexity.

Inventive Principle:
Principle #6Universality (Multi-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 configuration enhances cooling performance by uniformly spraying coolant onto coils and heat-producing areas, reducing temperature differences between motor ends and achieving desired operation characteristics.

Implementation Method 1

the bulkhead has nozzle hole portions passing through the bulkhead from an outer peripheral surface to an inner peripheral surface of the bulkhead and arranged in a circumferential direction over an entire circumference of the bulkhead to allow the coolant flowing in the gap to be ejected to an interior space defined by the bulkhead

Methodology Applied
Scientific EffectFluid spray: Fluid Spray

Data Source

PatentEP4329158A1Liquid cooling structure for motor
Publication Date: 2024.02.28 KUBOTA CORP
  • EP4329158A1 patent drawingFigure 1
  • EP4329158A1 patent drawingFigure 2
  • EP4329158A1 patent drawingFigure 3

AI summary

A liquid cooling structure for a motor (1) includes: a substantially cylindrical casing (2); a substantially annular end plate (3) provided in an annular manner at a cylinder end of the casing (2); a stator (4) housed in the casing (2); a rotor (5) held in a hollow portion of the stator (4) such that the rotor (5) is rotatable about an axis (L1) passing through a center of the stator (4); and a substantially cylindrical bulkhead (16) extending along a direction of extension of the axis (L1) from an inner surface of the end plate (3) and provided inward of the casing (2) such that the bulkhead (16) faces an inner peripheral surface of the casing (2) with a gap (20) between the bulkhead (16) and the inner peripheral surface to allow coolant to flow through the gap (20), wherein the casing (2) has a coolant inlet (11) passing through the casing (2) from an outer peripheral surface to the inner peripheral surface of the casing (2) to guide externally supplied coolant to the gap (20), the stator (4) includes a substantially annular stator core (6) having teeth (14) on an inner peripheral portion of the stator core (6) such that the teeth (14) protrude from the inner peripheral portion of the stator core (6), and coils (7) wound around the respective teeth (14) at positions inward of the bulkhead (16), and the bulkhead (16) has nozzle hole portions (21) passing through the bulkhead (16) from an outer peripheral surface to an inner peripheral surface of the bulkhead (16) and arranged in a circumferential direction over an entire circumference of the bulkhead (16) to allow the coolant flowing in the gap (20) to be ejected to an interior space defined by the bulkhead (16).