Switchable Ball Joint Structure for Stable Spatial Positioning
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Solution Overview
Problem
Current ball joints with three degrees of freedom fail to achieve stable spatial positioning control, particularly in dynamic applications like camera pan-tilt mechanisms, as they cannot effectively control the horizontal plane during shooting.
Innovation Solution
A two-degree-of-freedom and three-degree-of-freedom switchable ball joint structure is designed, featuring a hollow sphere with a groove, a limiting pin, and worm gear assemblies to adjust the sphere's rotational freedom, allowing for simple and convenient switching between two and three degrees of freedom by controlling the limiting pin's insertion into or out of the groove.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a three-degree-of-freedom ball joint structure is used, then the sphere can rotate freely in all directions, but stable spatial positioning control cannot be achieved
Solution Approach 1:
The ball joint structure dynamically switches between three-degree-of-freedom and two-degree-of-freedom modes based on operational requirements. The limiting pin can be positioned to either constrain or release rotation about a specific axis, allowing the system to adapt its degrees of freedom in real-time. This dynamic reconfiguration enables both free rotation when needed and stable positioning when required, resolving the contradiction between rotational freedom and positioning control.
2Reliability
If a two-degree-of-freedom ball joint structure is used, then stable spatial positioning control can be achieved, but rotational freedom is reduced
Solution Approach 1:
The switchable mechanism allows the ball joint to transition between two-degree-of-freedom and three-degree-of-freedom configurations. By adjusting the limiting pin position or removing constraints, the system can switch from a constrained two-DOF mode with stable positioning to an unconstrained three-DOF mode with full rotational freedom, thus resolving the contradiction between positioning stability and rotational versatility.
3Adaptability or versatility
If a switchable mechanism is added to change degrees of freedom, then both two-DOF and three-DOF modes can be achieved, but device complexity increases
Solution Approach 1:
The switching mechanism is segmented into independent, modular components: a limiting pin with positioning features, discrete grooves or slots on the sphere, and simple constraint elements. Each component performs a specific function, and they can be independently manufactured and assembled. This segmentation reduces overall complexity by avoiding a monolithic complex mechanism while enabling smooth transitions between two-DOF and three-DOF modes.
4Adaptability or versatility
If a limiting pin with groove structure is used, then degree of freedom switching is enabled, but manufacturing precision requirements increase
Solution Approach 1:
The groove or slot on the sphere is designed with an asymmetric cross-section that matches the limiting pin's geometry. This asymmetric pairing creates a unique fit that enables precise positioning without requiring extremely tight manufacturing tolerances. The asymmetric shape provides self-centering and anti-rotation features, allowing the limiting pin to engage the groove with adequate precision using conventional manufacturing methods.
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 enables stable spatial positioning control by restricting or allowing rotational freedom, providing a simple structure for adjustment and enhancing dynamic balance and dustproof sealing, while ensuring continuous resistance and locking force for precise positioning.
Implementation Method 1
a first worm gear assembly, which is provided in the outer shell for driving the limiting pin to make a linear reciprocating motion in the vertical direction
Implementation Method 2
the aperture value M of the top of the inner ring of the dustproof pad is smaller than the diameter value N of the spherical surface corresponding to the top of the dustproof pad on the sphere, so that the top of the dustproof pad is tensioned on the sphere under the action of the annular groove
Data Source
AI summary
The present invention discloses a two-degree-of-freedom and three-degree-of-freedom switchable ball joint structure, comprising: an outer shell with an accommodating cavity; a hollow sphere, which is located in the accommodating cavity of the outer shell and is rotatable in the accommodating cavity, wherein the lower hemispherical surface of the sphere is provided with a groove; a limiting pin, which is vertically inserted in the outer shell and located below the sphere, and the axis line of which passes through the center of the sphere; a first worm gear assembly, which is provided in the outer shell for driving the limiting pin to make a linear reciprocating motion in the vertical direction. The two-degree-of-freedom and three-degree-of-freedom switchable ball joint structure has the advantages of simple structure and convenient adjustment.