Transmission Oil Reservoir Float Valve for Stable Lubrication

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Solution Overview

Problem

Existing transmission systems face challenges in maintaining a consistent oil level in the first oil reservoir, which is essential for lubrication and cooling, due to steady outflow and lack of effective regulation mechanisms.

Innovation Solution

A connection line between the first and second oil reservoirs, equipped with a passive mechanical-hydraulic valve arrangement, including a float and plug, allows for automatic regulation of the oil level by opening or closing to maintain a predefined level, using a pump to replenish oil from the second reservoir.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a pump continuously draws oil from the first oil reservoir, then the transmission components are adequately lubricated and cooled, but the oil level in the first oil reservoir drops below a predefined level

Engineering Contradiction:

Improvelubrication reliabilityVSAvoidoil level

Core Design Contradiction:

ReliabilityVSQuantity of substance

Solution Approach 1:

The patent implements a feedback mechanism using a float that rises and falls with the oil level in the first reservoir. When the oil level drops below a predefined threshold, the float triggers the opening of a connection line, allowing oil to flow from the second reservoir to replenish the first reservoir. This closed-loop feedback system automatically maintains the oil level within acceptable ranges, ensuring continuous reliable lubrication while preventing complete depletion of oil in the first reservoir.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The system enables self-service by automatically replenishing oil from the second reservoir to the first reservoir through the float-controlled connection line mechanism. The float actuates the valve opening/closing based on oil level conditions without external intervention, allowing the transmission system to self-regulate its oil distribution and maintain operational reliability autonomously.

Inventive Principle:

Principle #25Self-service

2Reliability

If the oil level in the first oil reservoir is maintained at a maximum level, then lubrication is ensured, but drag torques increase and torque transmission efficiency decreases

Engineering Contradiction:

Improvelubrication availabilityVSAvoiddrag torque

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The patent dynamically changes the oil level parameter in the first reservoir by controlling the connection line between the first and second reservoirs. Instead of maintaining a constant maximum oil level, the system adjusts the oil level within a defined range using a float-controlled valve mechanism. This parameter adjustment ensures sufficient lubrication while preventing excessive oil levels that would submerge gearwheels and increase drag torques, thereby optimizing torque transmission efficiency.

Inventive Principle:

Principle #35Parameter changes

3Measurement precision

If a valve arrangement with electrical components is used to control the connection line, then precise oil level regulation is achieved, but device complexity and cost increase

Engineering Contradiction:

Improveoil level detection precisionVSAvoidvalve arrangement complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces complex electrical sensing and control systems with a simple mechanical float-based valve arrangement. The float mechanically responds to oil level changes and directly actuates the valve opening/closing through buoyancy forces. This mechanical substitution achieves sufficient oil level detection precision without requiring electrical components, sensors, or electronic control circuits, thereby significantly reducing device complexity and manufacturing cost while maintaining adequate regulation functionality.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 ensures a stable oil level in the first reservoir, reducing drag torques and enhancing torque transmission efficiency, particularly in dual clutch transmissions where gearwheels remain above the oil level, thus improving the transmission's operational efficiency.

Implementation Method 1

the valve arrangement may include a float which floats in the oil of the first oil reservoir

Methodology Applied

Scientific EffectBuoyancy: Archimedes' Principle (Buoyancy)

Implementation Method 2

the oil pump draws oil from the first oil reservoir, which is replenished from the second oil reservoir

Methodology Applied

Scientific EffectPumping: Pump

Implementation Method 3

the valve arrangement may include a plug which covers an opening in the connection line

Methodology Applied

Scientific EffectMechanical sealing: Mechanical Fastener

Data Source

PatentUS11585431B2Transmission and motor vehicle

Publication Date: 2023.02.21 ZF FRIEDRICHSHAFEN AG

AI summary

A transmission includes a first oil reservoir and a second oil reservoir. The first oil reservoir, in an installed position, lies underneath the second oil reservoir. The first oil reservoir and the second oil reservoir are connected via a connection line. The connection line is configured to open or close depending on an oil level in the first oil reservoir. A related motor vehicle is also provided.