Self-Pivoting Drive with Internal Gears for Spherical Motion Simulators
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Solution Overview
Problem
Existing motion simulator drive mechanisms, such as those for virtual reality systems, face limitations in accuracy due to external gear placement, lubrication challenges, and exposure to dirt, particularly in systems using a ring gear and spur gear arrangement.
Innovation Solution
A common-axis double-wheel arrangement with each wheel driven by a separate motor, where the wheels are mounted on a pivoting frame that freely rotates, allowing for controlled differential rotation and enclosing all gears within the rotating frame to enhance accuracy and protection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If gears are mounted exterior to the rotating frame, then the drive mechanism can be implemented, but the accuracy of rotation positioning is restricted and the gears are exposed to dirt and lubrication is difficult
Solution Approach 1:
The patent places the ring gear and spur gears inside the rotating frame, nesting the gear train within the protected enclosure. This allows the gears to be shielded from external contaminants while still functioning to drive the wheels, resolving the contradiction between protection and positioning accuracy
Solution Approach 2:
Instead of mounting gears outside the rotating frame as in prior art, the invention inverts the arrangement by mounting all gears inside the rotating frame. This reversal protects the gears from dirt while maintaining drive functionality, and eliminates the need for external gear-motor mounting close to the rotating frame
2Power
If a single large motor is used for sphere rotation, then the rotation can be achieved, but the device complexity and size increase
Solution Approach 1:
The patent divides the single large motor into two separate smaller motors, each driving one of the two drive wheels. This segmentation reduces the complexity and size of individual motors while achieving the same overall rotation capability through coordinated operation of both motors
Solution Approach 2:
The patent combines the functions of two small motors to achieve the rotation capability previously requiring one large motor. The motors work together in parallel, with their combined effect producing the necessary sphere rotation while reducing overall system complexity
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 improves the accuracy and reliability of sphere rotation by eliminating the need for external gear placement, facilitating continuous lubrication, and protecting gears from dirt, while using two smaller motors instead of one larger motor for sphere rotation, and includes an angle encoder for precise direction measurement without slip-rings.
Implementation Method 1
the two wheels are in frictional contact with the driven surface, so controlled differential rotation of the wheels is used to set the direction of the axis of the wheels
Data Source
AI summary
This mechanism for driving motions of a surface of spherical, ellipsoidal, plane, or other shape comprises a pair of drive wheels mounted on a freely pivoting frame, each wheel being driven by its own bidirectional motor. The motors and the active electronics of an angle encoder are mounted in an associated fixed frame, so no slip rings or other rotating connections are needed for motor power and control, or for determining the rotation angle of the pivoting frame. Control of the motors provides differential rotation of the two wheels to effect controlled rotation of the pivoting frame, and therefore of wheel direction. This avoids the use of a separate motor for changing the direction of motion of the surface. All parts of the mechanism driving wheel rotation are enclosed by the pivoting frame or the fixed frame.