Cam Disc Coupling for Vehicle HVAC Flap Actuation

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Solution Overview

Problem

Modern air conditioning systems for vehicles require additional control elements and motors to fully utilize the degree of freedom introduced by the evaporator bypass flap, leading to increased installation space, weight, and costs, while existing solutions mechanically couple the temperature mixing flap with the evaporator bypass flap, complicating the regulation of interior vehicle temperature.

Innovation Solution

Mechanical connection of the temperature mixing flap and evaporator bypass flap via a cam disc with a cam groove and lever arrangement, allowing for forced coupling of their movements with a single actuator, reducing the need for additional motors and optimizing the use of the evaporator bypass flap's degree of freedom.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the evaporator bypass flap is used to regulate interior temperature, then temperature control flexibility is improved, but the number of required control elements and motors increases

Engineering Contradiction:
Improvetemperature control flexibilityVSAvoidnumber of control elements and motors
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent combines the control of the evaporator bypass flap and temperature mixing flap into a single integrated control mechanism. The cam disc with cam groove receives a single actuating signal and mechanically coordinates both flaps, reducing the number of independent motors and control elements while maintaining temperature control flexibility through the coordinated movement of both flaps.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The cam disc mechanism serves multiple functions: it controls both the evaporator bypass flap and temperature mixing flap, translates rotational movement into coordinated flap positioning, and enables temperature regulation across different operating ranges using a single control system. This multi-functionality reduces overall system complexity while maintaining adaptability.

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

2Weight of stationary object

If the temperature mixing flap and evaporator bypass flap are mechanically coupled, then installation space and weight are reduced, but the regulation of interior vehicle temperature becomes more complex

Engineering Contradiction:
Improveair conditioning device weightVSAvoidtemperature regulation simplicity
Core Design Contradiction:
Weight of stationary objectVSEase of operation

Solution Approach 1:

The mechanically coupled flap system provides self-service by automatically coordinating the position of the evaporator bypass flap and temperature mixing flap based on a single control input. The cam groove geometry is designed to automatically position both flaps in appropriate configurations for different temperature ranges without requiring complex electronic control logic, thereby simplifying operation despite the mechanical coupling.

Inventive Principle:
Principle #25Self-service

3Measurement precision

If additional motors are installed for independent flap control, then temperature regulation precision is improved, but energy consumption and noise increase

Engineering Contradiction:
Improvetemperature regulation precisionVSAvoidenergy consumption
Core Design Contradiction:
Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The patent merges the actuation of two flaps into a single motor-driven cam disc system. This reduces energy consumption by eliminating redundant motors while maintaining temperature regulation precision through the mechanical coordination provided by the cam groove, which ensures both flaps are positioned correctly for the desired temperature range.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The cam disc acts as an intermediary mechanism that translates a single motor's rotational movement into coordinated positioning of both flaps. This intermediary mechanism enables precise temperature control through mechanical leverage and geometric design without requiring multiple independent motors, thereby reducing energy consumption and noise while maintaining control precision.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 simplifies temperature regulation by allowing variations in interior temperature to be controlled solely by the evaporator operation below a lower limit temperature, and by the evaporator bypass flap between limit temperatures, reducing energy consumption and noise, and extending the range in electric or hybrid vehicles.

Implementation Method 1

an evaporator of a refrigerant circuit through which at least parts of the air flow can flow

Methodology Applied
Scientific EffectHeat exchange: Heat Exchanger

Implementation Method 2

a heating heat exchanger through which at least parts of the air flow can flow

Methodology Applied
Scientific EffectHeat exchange: Heat Exchanger

Data Source

PatentEP2774790B2Air conditioning device for a motor vehicle and control method for the same
Publication Date: 2019.03.20 VOLKSWAGEN AG
  • EP2774790B2 patent drawingFigure 1
  • EP2774790B2 patent drawingFigure 2
  • EP2774790B2 patent drawingFigure 3~4

AI summary

The device (10) has an intake channel (18) for introduction of airflow, and a heat exchanger (16) arranged behind a vaporizer (14) for flowing the air. Amount of the air flowing through the vaporizer of a refrigerant cycle and a pivotable vaporizer bypass flap (20) is adjusted. A temperature mixture flap (26) and the vaporizer bypass flap are mechanically connected with each other, where pivoting movements of the temperature mixture flap and the vaporizer bypass flap are positively coupled. A rotatable stored cam (36) is formed with a curve groove (38). An independent claim is also included for a method for carrying out temperature regulation in an inner space of a motor car.