Split-Rotor Rotary Valve With Clearance Sealing for Low Torque

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Solution Overview

Problem

Existing rotary valves for thermal management in electric vehicles face issues with increased leakage and drive torque due to high friction and cylindricity tolerances, especially when multiple flow passages are required, leading to larger actuators and higher power consumption.

Innovation Solution

A rotary multi-way valve with a clearance seal structure that allows split rotors to self-align and minimize friction, using a minute gap for radial movement, reducing leakage and drive torque, and incorporating a shaft with a specific diameter difference to facilitate alignment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a rotary valve with multiple flow passages is used to achieve various circulation patterns, then the system complexity is reduced and versatility is improved, but friction increases and leakage worsens

Engineering Contradiction:

Improvecirculation pattern switching capabilityVSAvoidfluid leakage

Core Design Contradiction:

Adaptability or versatilityVSObject-generated harmful factors

Solution Approach 1:

The patent changes the sealing parameter from contact-based sealing to clearance-based sealing. By precisely controlling the radial clearance between the rotor outer peripheral surface and stator inner peripheral surface (0.01-0.05mm), the system achieves effective sealing without contact friction, resolving the contradiction between versatility and leakage

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent replaces the mechanical contact sealing system with a hydrodynamic clearance sealing system. The rotor and stator rotate within a fluid film, eliminating direct mechanical contact while maintaining sealing effectiveness, thus reducing both friction and leakage

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If traditional contact sealing is used to prevent leakage, then sealing effectiveness is improved, but friction increases and drive torque worsens

Engineering Contradiction:

Improvesealing effectivenessVSAvoiddrive torque

Core Design Contradiction:

ReliabilityVSForce

Solution Approach 1:

The patent substitutes mechanical contact sealing with hydrodynamic clearance sealing. The rotor and stator surfaces rotate within a fluid film, eliminating direct mechanical contact while maintaining sealing effectiveness, thus reducing both friction and drive torque

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent uses the hydraulic principle of fluid film lubrication to achieve sealing. The coolant or heating medium itself forms a lubricating film between the rotor and stator, providing both sealing and lubrication functions without requiring additional mechanical contact components

Inventive Principle:

Principle #29Pneumatics and hydraulics

3Reliability

If high sealing precision is maintained to reduce leakage, then reliability is improved, but manufacturing precision requirements increase and cost worsens

Engineering Contradiction:

Improvesealing reliabilityVSAvoidcylindricity tolerance

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The patent changes the sealing mechanism from relying on surface contact pressure to relying on controlled radial clearance. This allows for larger cylindricity tolerances (0.02-0.05mm) while maintaining sealing effectiveness through the hydrodynamic film, significantly reducing manufacturing precision requirements

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The system uses the flowing coolant or heating medium itself to maintain the clearance and provide lubrication. The fluid pressure automatically maintains the rotor-stator gap, eliminating the need for high-precision mechanical sealing components and reducing manufacturing requirements

Inventive Principle:

Principle #25Self-service

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 reduces fluid leakage and drive torque, enabling downsized actuators and lower power consumption while allowing flexible flow patterns for thermal management systems.

Implementation Method 1

A minute gap is formed between the at least one split rotor and an inner wall of the housing hole to enable minute movement of the at least one split rotor in the radial direction

Methodology Applied

Scientific EffectPressure differential: Pressure Gradient

Data Source

PatentUS20250237312A1Rotary multi-way valve

Publication Date: 2025.07.24 DENSO CORP

AI summary

A housing has a housing hole shaped in a cylindrical form. A plurality of ports are arranged in an axial direction, a circumferential direction or a radial direction of a housing hole. At least one split rotor is arranged in the housing hole in the axial direction. A communication passage is formed in the at least one split rotor and is configured to switch between a communicating state and a blocking state between a predetermined one of the plurality of ports and another one of the plurality of ports. A shaft is configured to rotate the at least one split rotor around a central axis of the housing hole. A minute gap is formed between the at least one split rotor and an inner wall of the housing hole to enable minute movement of the at least one split rotor in the radial direction.