Parking Robot Crank Mechanism for Variable Wheel Lifting Force

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Solution Overview

Problem

Existing parking robots face challenges in efficiently lifting vehicle wheels due to varying forces required throughout the lifting process, necessitating a mechanism that can provide a variable force to manage these changes effectively.

Innovation Solution

A parking robot design featuring wheel support arms with a crank element and eccentric pulley mechanism, allowing for a rotational movement that adjusts the force applied to the wheel as needed, ensuring efficient lifting and lowering of vehicle wheels.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a conventional lifting mechanism with constant force is used, then the structure is simple, but it cannot efficiently handle the varying forces required throughout the lifting process

Engineering Contradiction:
Improvelifting efficiencyVSAvoidmechanism complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent applies the dynamics principle by implementing a crank element mechanism that transforms constant rotational motion into variable linear motion. The crank element converts the constant torque from the drive unit into a variable lifting force that adapts to the changing mechanical advantage required at different stages of wheel elevation, thereby improving lifting efficiency without requiring a complex variable-speed drive system.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent employs parameter changes by utilizing the eccentric pulley mechanism where the effective lever arm length varies continuously during the lifting stroke. As the wheel is raised, the distance between the crank element's rotation center and the lifting point changes, automatically adjusting the force multiplication ratio to match the decreasing load moment, thus optimizing lifting efficiency across the entire range of motion.

Inventive Principle:
Principle #35Parameter changes

2Power

If a variable force mechanism is implemented to handle lifting forces, then lifting efficiency improves, but the device complexity increases

Engineering Contradiction:
Improvevariable force capabilityVSAvoidmechanism complexity
Core Design Contradiction:
PowerVSDevice complexity

Solution Approach 1:

The patent merges multiple functions into a single integrated mechanism. The crank element simultaneously serves as the rotating component, the force transmission element, and the variable lever arm. The eccentric pulley combines the rotation control and force application functions in one component, eliminating the need for separate mechanisms and reducing overall system complexity while maintaining variable force capability.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent utilizes curved geometry in the crank element and eccentric pulley design to achieve variable force transmission. The circular path of the crank element's rotation center and the eccentric offset create a naturally varying moment arm length during rotation, providing the required variable force characteristic through geometric design rather than complex control systems.

Inventive Principle:
Principle #14Spheroidality (Curvature)

3Volume of moving object

If a compact lifting mechanism is used, then installation space is reduced, but the ability to handle heavy vehicles may be compromised

Engineering Contradiction:
Improveinstallation spaceVSAvoidlifting force capability
Core Design Contradiction:
Volume of moving objectVSForce

Solution Approach 1:

The patent implements a mechanical advantage system where the eccentric pulley mechanism creates a counterbalancing effect. During the lifting stroke, the varying lever arm lengths naturally compensate for the changing load conditions, allowing a compact mechanism to generate sufficient lifting force for heavy vehicles through optimized force distribution rather than requiring oversized components.

Inventive Principle:
Principle #8Anti-weight (Counterweight)

Solution Approach 2:

The crank element mechanism utilizes periodic rotational motion to achieve continuous variable force transmission. Each complete rotation of the crank element provides a full lifting cycle with automatically varying force characteristics, enabling the compact mechanism to handle heavy vehicles through rhythmic, cyclical force application rather than requiring sustained high force throughout the stroke.

Inventive Principle:
Principle #19Periodic action

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 enables reliable and efficient lifting of vehicle wheels, allowing for autonomous transport over ramps and steps, with a compact and cost-effective design that ensures the parking robot can handle heavy vehicles with minimal installation space and reduced energy consumption.

Implementation Method 1

a variable force can be provided with which a wheel of a motor vehicle can be lifted by means of a lever, that is to say, for example, a wheel support arm of the parking robot

Methodology Applied
Scientific EffectMechanical Advantage: Mechanical Advantage

Implementation Method 2

wheel support arms with a crank element and eccentric pulley mechanism, allowing for a rotational movement that adjusts the force applied to the wheel

Methodology Applied
Scientific EffectEccentric mechanism: Eccentric

Data Source

PatentEP3663487B1Parking robot for a motor vehicle and method for operating same
Publication Date: 2021.07.21 VOLKSWAGEN AG
  • EP3663487B1 patent drawingFigure 1
  • EP3663487B1 patent drawingFigure 2
  • EP3663487B1 patent drawingFigure 3

AI summary

The invention relates to a parking robot (20) for a motor vehicle (10) and a method for operating such a parking robot (20). The parking robot (20) has a pair of wheel support arms (36), each of which is rotatably mounted about a respective axis of rotation (39), at least indirectly by means of a crank element (60). The parking robot (20) is designed to autonomously drive from the outside next to a wheel (14) of a wheel axle (12) of the motor vehicle (10) into a receiving position in which the respective wheel support arms (36) are arranged parallel to the wheel axle (12) and one of the wheel support arms (36) is positioned in front of the wheel (14) in a longitudinal direction of the vehicle and the other wheel support arm (36) is positioned behind the wheel (14) in a longitudinal direction of the vehicle.The parking robot (20) is also designed to lift the wheel (14) of the motor vehicle (10) by rotating the respective wheel support arm (36) about the respective axis of rotation (39) in a predetermined direction of rotation, the respective directions of rotation of the respective wheel support arms (36) being opposite to each other.