Spherical Wheel Caps with Secant Pivot Axes

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Conventional spherical wheels with motor shafts entering through the equatorial plane experience discontinuity issues, leading to loss of grip and noise during rotation, especially when the wheel is driven at high speeds, due to the rigidity requirements of the motor shaft and the separation of hemispheres.

Innovation Solution

The design features two caps with surfaces following the spherical wheel, each articulated by a pivot connection with an axis perpendicular to the cap's plane, where the pivot connection axes are secant and not aligned, allowing for a larger diameter motor shaft without increasing the discontinuity, and incorporating rollers for enhanced contact and reduced slippage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If the motor shaft diameter is increased to improve rigidity, then the shaft rigidity is improved, but the discontinuity in wheel support increases

Engineering Contradiction:
Improvemotor shaft rigidityVSAvoidwheel support continuity
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The wheel is divided into two separate caps (first cap and second cap) that are articulated relative to each other via pivot connections. This segmentation allows each cap to be supported independently by the ground, eliminating the discontinuity problem that would result from increasing motor shaft diameter in a unified wheel structure.

Inventive Principle:
Principle #1Segmentation

2Strength

If the two hemispheres are separated to accommodate a rigid motor shaft, then the motor shaft rigidity is improved, but the discontinuity in wheel support increases

Engineering Contradiction:
Improvemotor shaft rigidityVSAvoidwheel support continuity
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The two caps are connected via pivot connections that allow relative rotation between them. This dynamic connection enables the caps to adapt their positions independently, maintaining continuous ground support while accommodating the rigid motor shaft that passes through the equatorial plane between the caps.

Inventive Principle:
Principle #15Dynamics

3Ease of manufacture

If the equatorial plane is positioned vertically, then the motor shaft can be accommodated, but discontinuity in ground support occurs during wheel rotation

Engineering Contradiction:
Improvemotor shaft accommodationVSAvoidground support continuity
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

By segmenting the wheel into two independently articulated caps, the invention eliminates the discontinuity that would occur when the equatorial plane passes through the ground during rotation. Each cap maintains its own support relationship with the ground, ensuring continuous support throughout the rotation cycle.

Inventive Principle:
Principle #1Segmentation

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 configuration maintains consistent contact with the ground, reduces friction, and prevents slippage, enabling smoother operation and increased rigidity of the motor shaft while minimizing the discontinuity in the wheel's support on the ground.

Implementation Method 1

The caps are each articulated by means of a pivot connection relative to the shaft, an axis of each of the pivot connections being perpendicular to the plane of the cap in question

Methodology Applied
Scientific EffectPivot connection rotation: Hinge

Data Source

PatentEP2844498B1Spherical wheel, and vehicle implementing the wheel
Publication Date: 2017.10.04 ALDEBARAN ROBOTICS SA
  • EP2844498B1 patent drawingFigure 1
  • EP2844498B1 patent drawingFigure 2
  • EP2844498B1 patent drawingFigure 3

AI summary

The invention relates to a spherical wheel (10) for moving a vehicle, and to a vehicle implementing the wheel, wherein the wheel (10) is rotated by a shaft (12) that is rotatable about an axis (14). According to the invention, the wheel (10) includes two hemispherical shells (15, 16), the surfaces of which follow the spherical surface of the wheel (12) and each of which is delimited by a plane (17, 18). The hemispherical shells (15, 16) are each pivotable, via a pivot linkage, relative to the shaft (12), an axis (21, 22) of each of the pivot linkages being perpendicular to the plane (17, 18) of the hemispherical shell (15, 16) in question. The planes (17, 18) delimiting the two hemispherical shells (15, 16) intersect.