Rack Gear with Release Feature for Sequential Flap Actuation

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Solution Overview

Problem

Existing mechanisms for controlling two rotating members with parallel rotation axes and fixed distances between them are complex and costly, particularly when sequential control is required, as seen in motor vehicle air conditioning systems, where coordinating multiple actuation systems is inefficient.

Innovation Solution

A mechanism utilizing a gear wheel, lever, and rack member with a follower portion and control profile allows for sequential actuation of two rotating members using a single kinematic chain, where the gear wheel remains stationary during the first travel section and only engages with the rack member's toothing later, enabling simultaneous rotation and controlled sequential operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a single actuation system is used to control two flaps, then device complexity and cost are reduced, but sequential control of the flaps becomes difficult to achieve

Engineering Contradiction:
Improveactuation system complexityVSAvoidsequential control capability
Core Design Contradiction:
Device complexityVSEase of operation

Solution Approach 1:

The rack member is segmented into two distinct functional sections: a first travel section with a control profile that engages the follower portion, and a second travel section with a toothing that engages the gear wheel. This segmentation allows the single actuation system to produce different motion outcomes in different phases of operation, enabling sequential control of the two flaps while maintaining system simplicity

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The mechanism performs preliminary action by engaging the follower portion with the control profile during the first travel section before the gear wheel engagement occurs. This preliminary engagement ensures that the first flap is positioned correctly and the second flap remains stationary before simultaneous rotation begins, enabling precise sequential control

Inventive Principle:
Principle #10Preliminary action

2Ease of operation

If two separate actuation systems are used for sequential flap control, then sequential control is achieved, but device complexity and cost increase

Engineering Contradiction:
Improvesequential control capabilityVSAvoidactuation system complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The single actuation system performs multiple functions through the rack member's dual-section design. The same rack member sequentially engages different components (follower portion then gear wheel) to achieve both individual flap control and simultaneous flap rotation, eliminating the need for separate actuation systems while maintaining sequential control capability

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

Solution Approach 2:

The rack member acts as an intermediary mechanism that translates the single actuation system's linear motion into differentiated rotational movements. By incorporating both the control profile and toothing on the same rack member, it mediates between the single actuator and the two flaps, enabling sequential control without requiring multiple actuators

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 the control of two rotating members by allowing sequential actuation with a single kinematic chain, reducing complexity and cost while ensuring precise control, particularly in air distribution systems of motor vehicles.

Implementation Method 1

The gear wheel (30) comprises a toothing (301) which is adapted to be engaged by the toothing (406) of the rack member (40) in a second travel section of the rack member (40)

Methodology Applied
Scientific EffectGear mechanism: Gear

Implementation Method 2

The gear wheel (30) comprises a follower portion (302) which is adapted to be engaged by the control profile (405) of the rack member (40) in a first travel section of the rack member (40)

Methodology Applied
Scientific EffectMechanical constraint: Cam

Data Source

PatentEP3456562B1A rack gear with release feature
Publication Date: 2020.08.19 DENSO THERMAL SYST SPA
  • EP3456562B1 patent drawingFigure 1
  • EP3456562B1 patent drawingFigure 2
  • EP3456562B1 patent drawingFigure 3~4

AI summary

A mechanism for connecting a first and a second rotating member (A, B), comprising a lever (20) adapted to be rigidly connected to the first member (A), a gear wheel (30) adapted to be rigidly connected to the second member (B), the gear wheel (30), comprising a toothing (301) and a follower portion (302) protruding beyond the profile of the gear wheel (30), and a rack member (40) connected to the lever (20) by means of a linkage (403) and movable in a constrained manner between a first end position and a second end position. The rack member (40) comprises a control profile (405) adapted to be engaged at one end (303) of the follower portion (32) of the gear wheel (30) in a first travel section between the first end position and the second end position, and a toothing (406) adapted to be engaged by the toothing (301) of the gear wheel (30) in a second travel section between the first end position and the second end position. The control profile keeps the gear wheel (30) still when the gear wheel is in the first travel section of the rack member (40).