Hydraulic Motor Casing Cooling via Throttle Passage

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Solution Overview

Problem

Existing hydraulic motors suffer from insufficient cooling of the casing, particularly under varying operating conditions, due to limited flow of leak oil or reduced hydraulic oil pressure, which can lead to overheating of the reduction gear and casing.

Innovation Solution

The design incorporates a throttle passage that directs hydraulic oil from the brake release pressure passage to the casing chamber, where it circulates to absorb heat, and a low-pressure selective valve to manage oil flow, ensuring adequate cooling regardless of operating conditions by adjusting the flow amount based on the motor's operational state.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If leak oil is used to cool the casing, then the casing is cooled, but the flow amount is small and cooling may be insufficient

Engineering Contradiction:
Improvecasing temperatureVSAvoidflow amount of cooling oil
Core Design Contradiction:
TemperatureVSQuantity of substance

Solution Approach 1:

The hydraulic oil serving the capacity-varying mechanism is made to serve dual purposes: both controlling the motor capacity and cooling the casing. The oil that would otherwise only control the tilting actuator now also flows through the casing chamber to provide cooling, eliminating the need for separate cooling oil supply.

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

Solution Approach 2:

The cooling oil supply passage is merged with the capacity control system. The hydraulic oil that controls the tilting actuator is combined with the cooling function by directing it to flow into the casing chamber through the supplied oil passage, consolidating two functions into one oil flow path.

Inventive Principle:
Principle #5Merging (Combining)

2Speed

If hydraulic oil pressure is switched to low by speed switching valve, then traveling speed is controlled, but the flow amount of hydraulic oil to casing is reduced and cooling becomes insufficient

Engineering Contradiction:
Improvetraveling speedVSAvoidcasing temperature
Core Design Contradiction:
SpeedVSTemperature

Solution Approach 1:

The low-pressure selective valve acts as an intermediary device that ensures adequate cooling oil flow regardless of the main hydraulic pressure level. It selectively supplies oil to the casing chamber from appropriate sources, maintaining cooling effectiveness even when the main system operates at low pressure for speed control.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The system changes the pressure parameter of the cooling oil by using the low-pressure selective valve to select appropriate oil sources. When main hydraulic pressure is low, the valve redirects oil flow to maintain sufficient cooling, effectively adapting the cooling system to different pressure conditions.

Inventive Principle:
Principle #35Parameter changes

3Power

If hydraulic oil is led to capacity-varying mechanism, then motor capacity is controlled, but cooling of casing is insufficient when pressure is low

Engineering Contradiction:
Improvemotor capacityVSAvoidcasing temperature
Core Design Contradiction:
PowerVSTemperature

Solution Approach 1:

The hydraulic oil supply system is designed to serve multiple functions simultaneously: controlling the capacity-varying mechanism and cooling the casing. The same oil flow that adjusts motor capacity also provides cooling, ensuring both functions are maintained without requiring separate dedicated systems.

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 solution effectively maintains the casing and reduction gear at a lower temperature, preventing overheating and ensuring sufficient cooling during both high-speed operation and idle states, thereby extending the lifespan of components and maintaining performance.

Implementation Method 1

hydraulic liquid that has flowed out from the throttle passage 50 into the casing chamber 58 circulates in the casing chamber 58, and the casing 59 is cooled

Methodology Applied
Scientific EffectHeat absorption: Absorption (physical)

Implementation Method 2

hydraulic liquid that has flowed out from the throttle passage 50 into the casing chamber 58 circulates in the casing chamber 58

Methodology Applied
Scientific EffectConvection: Convection

Data Source

PatentEP2806153B1Hydraulic motor
Publication Date: 2020.04.08 KYB CORP
  • EP2806153B1 patent drawingFigure 1
  • EP2806153B1 patent drawingFigure 2

AI summary

A hydraulic motor includes a motor mechanism that rotates by hydraulic liquid pressure led from a hydraulic liquid pressure source. The hydraulic motor includes a casing that defines a casing chamber which accommodates the motor mechanism, a brake mechanism that brakes the rotation of the motor mechanism, a brake release actuator that releases the braking of the brake mechanism by a brake release pressure led from the hydraulic liquid pressure source, and a throttle passage that is in communication with the casing chamber and extracts a portion of hydraulic liquid that is led into the brake release actuator and leads it to the casing chamber.