Handle-Free Car Door Opening with Variable-Ratio Rack-and-Pinion

Solution Overview

Problem

Existing opening devices for motor vehicle doors are structurally complex, prone to damage and wear, and occupy excessive space due to frictional contact and large interaction areas, which is problematic in vehicles with limited installation space.

Innovation Solution

The use of a rack-and-pinion gear with a spiral-shaped pinion and involute gearing, where the pinion engages with a gear rack, allowing for a compact and robust design that applies a travel-dependent force to the actuator, utilizing different transmission ratios throughout the actuating travel.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If an arc-shaped stop ring is used to interact with the door leaf, then the door can be opened, but the structure becomes complex and requires large space

Engineering Contradiction:

Improvedoor opening functionVSAvoidstructure complexity

Core Design Contradiction:

Ease of operationVSDevice complexity

Solution Approach 1:

The patent replaces the mechanical arc-shaped stop ring interaction with a magnetic field-based holding force. The electromagnetic actuator generates a magnetic field that holds the door closed, and reversing the current direction opens the door, eliminating complex mechanical interaction components.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent extracts and eliminates the arc-shaped stop ring and its interaction mechanism from the door opening system, retaining only the essential holding and opening functions through electromagnetic actuation.

Inventive Principle:

Principle #2Taking out (Extraction)

2Ease of operation

If an arc-shaped stop ring is used to interact with the door leaf, then the door can be opened, but the installation space required increases

Engineering Contradiction:

Improvedoor opening functionVSAvoidinstallation space

Core Design Contradiction:

Ease of operationVSArea of stationary object

Solution Approach 1:

The patent replaces the mechanical arc-shaped stop ring interaction with a magnetic field-based holding force. The electromagnetic actuator generates a magnetic field that holds the door closed, and reversing the current direction opens the door, eliminating complex mechanical interaction components.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent extracts and eliminates the arc-shaped stop ring and its interaction mechanism from the door opening system, retaining only the essential holding and opening functions through electromagnetic actuation.

Inventive Principle:

Principle #2Taking out (Extraction)

3Reliability

If frictional contact is used between the stop ring and door leaf, then the door can be held, but wear and damage increase

Engineering Contradiction:

Improvedoor holding functionVSAvoidwear and damage

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent replaces the mechanical frictional contact with electromagnetic attraction. The electromagnetic actuator generates a magnetic field that holds the door closed without physical contact, eliminating wear and damage associated with frictional interfaces.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent replaces the mechanical frictional contact with electromagnetic attraction. The electromagnetic actuator generates a magnetic field that holds the door closed without physical contact, eliminating wear and damage associated with frictional interfaces.

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 design ensures a functional and compact structure that fits within limited vehicle space, minimizing wear and damage while providing efficient force application for opening the door, even in frozen conditions, with a sealed and protected installation.

Implementation Method 1

the electromotive drive acts on the actuator with the interposition of a rack-and-pinion gear

Methodology Applied

Scientific EffectRack and pinion: Rack and Pinion

Implementation Method 2

The engagement between the pinion and the relevant gear rack can advantageously be formed as an involute gearing

Methodology Applied

Scientific EffectInvolute gearing: Gear

Implementation Method 3

the rack-and-pinion gear works with different transmission ratios on the actuator along its actuating travel... the spiral-shaped pinion defines a rolling curve with a radius that grows along the actuating travel of the actuator

Methodology Applied

Scientific EffectSpiral geometry: Helix

Data Source

PatentUS20260043286A1Opening device

Publication Date: 2026.02.12 KIEKERT AG

AI summary

The invention relates to an opening device for a motor vehicle door, in particular a handle-free motor vehicle door such as, for example, a handle-free motor vehicle side door. For this purpose, the opening device has an electromotive drive (1 to 4) and an associated actuator (5) for acting on a door leaf. The actuator (5) acts on the door leaf with a travel-dependent force along its actuating travel (S). According to the invention, the electromotive drive (1 to 4) acts on the actuator (5) with the interposition of a rack-and-pinion gear (7,8), wherein the rack-and-pinion gear (7, 8) operates with different transmission ratios on the actuator (5) along its actuating travel (S).