Transmission Case Oil Cooling Structure Using Internal Rib Passages

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing oil cooling structures for engines require additional components and space to achieve effective cooling, leading to increased dimensions and complexity.

Innovation Solution

The transmission case is redesigned to utilize its dead spaces as storage and passage for oil, with rib walls partitioning the interior to enhance heat conduction and function as a large-capacity heat radiator, incorporating natural and forced air cooling, and integrating the oil pump within the transmission case to reduce component count and space requirements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If a separate oil cooler or cooling fin is provided around an oil passage, then the cooling effect of oil is improved, but the number of components and required space increase

Engineering Contradiction:
Improveoil temperatureVSAvoidnumber of components
Core Design Contradiction:
TemperatureVSDevice complexity

Solution Approach 1:

The patent merges the oil cooling function with the transmission case structure by forming oil storage chambers and passages directly within the transmission case body. The transmission case serves dual purposes: housing the transmission mechanism and functioning as an oil cooler, thereby eliminating the need for separate oil cooler components while achieving effective oil temperature reduction through the thermal mass and surface area of the transmission case

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The transmission case is designed to perform multiple functions simultaneously: it houses the transmission mechanism, stores oil, circulates oil through cooling passages, and acts as a heat radiator. This multi-functional design eliminates dedicated cooling components while maintaining effective oil cooling, directly resolving the contradiction between cooling performance and component complexity

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Temperature

If a separate oil cooler or cooling fin is provided around an oil passage, then the cooling effect of oil is improved, but the required space increases

Engineering Contradiction:
Improveoil temperatureVSAvoidrequired space
Core Design Contradiction:
TemperatureVSVolume of stationary object

Solution Approach 1:

The patent combines the oil cooling system with the transmission case structure, utilizing the existing volume of the transmission case to form oil storage chambers and cooling passages. This integration eliminates the need for additional external cooling components and their associated space, while the internal passages provide sufficient surface area for heat dissipation

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The oil storage chambers and cooling passages are nested within the transmission case structure, utilizing the internal volume of the transmission case for dual purposes. The passages are formed as cavities within the transmission case body, allowing the cooling system to be contained within the existing footprint without increasing overall dimensions

Inventive Principle:
Principle #7Nested doll (Nesting)

3Temperature

If dead spaces in the transmission case are utilized as storage and passage of oil, then the cooling performance is enhanced without increasing component count, but the transmission case structure becomes more complex

Engineering Contradiction:
Improveoil cooling performanceVSAvoidtransmission case structure
Core Design Contradiction:
TemperatureVSShape

Solution Approach 1:

The transmission case is segmented into multiple functional zones using partition walls: an oil storage chamber for oil reservoir, cooling passages for heat dissipation, and a transmission mechanism housing. This segmentation allows efficient utilization of dead spaces while maintaining a systematic and manufacturable structure, balancing the increased structural complexity with functional benefits

Inventive Principle:
Principle #1Segmentation

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 oil cooling performance while minimizing the number of components and space needed, providing efficient heat dissipation through both conduction and air cooling, and simplifies the assembly by using existing structural elements.

Implementation Method 1

heat conduction of the oil can be efficiently performed from the case inner chamber portions having a large capacity to the transmission case

Methodology Applied
Scientific EffectHeat conduction: Conduction (thermal)

Implementation Method 2

the transmission case exposed to outside is enabled to function as a heat radiator

Methodology Applied
Scientific EffectHeat radiation: Thermal Radiation

Implementation Method 3

in the transmission case, not only natural heat dissipation (radiant heat) but also forced heat dissipation by an air cooling action by cooling wind is performed

Methodology Applied
Scientific EffectForced convection: Forced Convection

Data Source

PatentEP3263855B1Oil cooling structure of engine
Publication Date: 2021.04.07 KUBOTA CORP
  • EP3263855B1 patent drawingFigure 1
  • EP3263855B1 patent drawingFigure 2
  • EP3263855B1 patent drawingFigure 3

AI summary

There is provided an oil cooling structure of an engine capable of enhancing cooling performance of oil while preventing an increase in number of components or an increase in required space from being involved as much as possible. In an oil cooling structure of an engine in which a transmission case 9 is attached to one end wall of an engine body, and a transmission mechanism 2A for accessory drive is provided in the transmission case 9, the transmission case 9 is formed into a potlid-shaped body having a plurality of rib walls 9B to 9H along a front-rear direction, and is attached to an engine front wall with an engine cooling fan, and case inner chamber portions 20, 22, 24, 30 partitioned by the rib walls 9B to 9H in the transmission case 9 are configured as a transporting passage W of oil circulated by an oil pump P.