R-Theta Table Segmentation for Rigidity and Thread Forming
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Solution Overview
Problem
Existing X-Y tables in machine tools face issues with rigidity, accuracy, and durability due to the double-layer configuration and high inertia weight, leading to vibration and abnormal trajectories during radial and circular movements. Additionally, internal thread processing methods for large diameters are limited by the need for high radial loads and the generation of chips during cutting, which complicates the processing of threads without grooves.
Innovation Solution
The R-θ table apparatus allows for free movement of a table on a plane without rotation, using a spherical bearing and a servo motor to change the horizontal distance between the main axis and the action point, enabling precise positioning and high rigidity. This apparatus is combined with a variable crank mechanism that adjusts the amplitude of the connection rod, allowing for efficient internal thread processing without chip generation by using an external thread shaped tool that molds the internal thread with a constant horizontal surface motion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If an X-Y table with a double-layer configuration is used to position a workpiece, then the table can move in multiple directions, but the rigidity deteriorates and the number of configuration components increases
Solution Approach 1:
The invention divides the movement functions into two independent single-layer systems: an R-axis system for radial movement and a θ-axis system for rotational movement. Each system has its own actuator and guide structure, eliminating the need for a double-layer configuration while maintaining full positioning capability and improving rigidity.
2Adaptability or versatility
If the entire γ-axis movable mechanism is loaded on a base that moves on the X-axis, then the table can be positioned in both directions, but the number of configuration components increases and rigidity deteriorates
Solution Approach 1:
The invention separates the γ-axis movable mechanism into two independent parts: the R-axis actuator mounted on the θ-axis table and the θ-axis actuator mounted on the base. This segmentation eliminates the need to load the entire γ-axis mechanism on a moving base, reducing component count and simplifying the overall structure.
3Productivity
If a single point tool is used for cutting internal threads of large diameter, then the processing can be performed, but chips are generated and the tool blade tip may be damaged
Solution Approach 1:
The invention replaces the mechanical cutting process with a forming process. An external thread-shaped tool is pressed against the workpiece to plastically deform and form the internal thread shape, eliminating chip generation and tool blade damage while maintaining processing capability for large diameter threads.
4Productivity
If the tube body is moved forward and rearward while rotating to process internal threads, then the thread can be cut, but the processing time is limited due to the need for multiple rotations
Solution Approach 1:
The invention replaces the multi-rotation cutting process with a single-pass forming process. The external thread-shaped tool forms the internal thread in one linear pass without requiring multiple rotations, dramatically reducing processing time while maintaining thread quality.
5Measurement precision
If the R-θ table apparatus uses a spherical bearing and servo motor to change the horizontal distance, then precise positioning is achieved, but the device complexity increases
Solution Approach 1:
The invention uses a spherical bearing that allows dynamic adjustment of the action axis orientation, combined with a servo motor for precise control of the horizontal distance. This dynamic system achieves high positioning precision while keeping the overall structure simpler than rigid multi-axis systems.
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 R-θ table apparatus improves rigidity and accuracy by eliminating the need for a double-layer configuration, enabling high-speed and precise movement without vibration, and allows for efficient internal thread processing of large diameters without chip generation, using a tool that molds the thread with a simple horizontal surface motion, thus overcoming the limitations of existing methods.
Implementation Method 1
a table (30) which is provided with a through hole (31) having a spherical bearing (35)
Data Source
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AI summary
There is provided an R-θ table apparatus which freely moves one table on a plane in the forward-and-rearward and leftward-and-rightward directions and in the rotational direction. The apparatus includes: a table which is provided with a through hole having a bearing; a guide member which holds the table to be horizontally freely movable; a driving apparatus which is provided with an action axis inserted being inclined to the bearing, and drives the action axis to be freely rotated and stopped; an elevating base which elevates the driving apparatus; an elevating apparatus which elevates the elevating base, and changes a position of an action point at which the action axis and the bearing are engaged with each other; and a base which is provided with a post that guides the elevating base and the guide member, and mounts the elevating apparatus, in which a horizontal distance between a center line of a main axis of the driving apparatus and the action point is changed by elevating the elevating base, and the table is moved to an arbitrary position without rotating along the guide member.