Lathe Threading Device Using Direct Electromagnetic Drive
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Solution Overview
Problem
Prior threading devices for medical applications suffer from machining defects and increased size due to clearance issues in kinematic chains, leading to reduced precision and quality, and require complex gear assemblies and belts that cause oscillations and wear.
Innovation Solution
A compact threading device with an electric rotor and stator coupled to a sleeve with refrigerating and lubricating channels, eliminating the need for gears and belts by using a brushless synchronous motor and MRAS control, which maintains precision and prevents chip deposition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If gears or belts are used to transmit rotary motion from the driving motor to the machining tool, then the motor can drive the tool, but clearances and oscillations are introduced that reduce precision and quality
Solution Approach 1:
The patent replaces the mechanical transmission system (gears or belts) with a direct electromagnetic coupling system. The brushless synchronous motor's rotor is directly coupled to the machining tool spindle, eliminating intermediate mechanical transmission components. This substitution removes the clearances and oscillations inherent in gear and belt systems, thereby improving thread surface precision and quality while reducing device complexity.
Solution Approach 2:
The patent merges the driving motor and machining tool into a single integrated unit. The rotor of the brushless synchronous motor is directly mounted on the spindle that holds the machining tool, combining the power source and tool holder into one component assembly. This merging eliminates the need for separate transmission mechanisms and reduces the number of parts, improving precision while simplifying the overall device structure.
2Ease of operation
If a belt transmission is used to drive the machining tool, then rotary motion can be transmitted, but the belt requires periodic controls for wear and tensioning
Solution Approach 1:
The patent replaces the belt transmission system with a direct electromagnetic drive. The brushless synchronous motor's rotor is directly coupled to the tool spindle, eliminating the belt entirely. This substitution removes the need for periodic belt maintenance (tensioning and wear checks) while ensuring consistent operational reliability, as there are no flexible elements that can stretch or wear.
Solution Approach 2:
The brushless synchronous motor design is inherently maintenance-free regarding transmission components. The direct electromagnetic coupling requires no external adjustment or maintenance of transmission elements, as the magnetic field transmission does not degrade over time like mechanical belts. The system serves itself by maintaining consistent performance without periodic human intervention for maintenance.
3Power
If a resilient element in the form of a belt is used to transmit rotary motion, then the motor can drive the tool, but inevitable undesired oscillations are generated
Solution Approach 1:
The patent replaces the flexible belt transmission with a rigid electromagnetic coupling system. The brushless synchronous motor's rotor is directly mounted on the spindle, creating a rigid connection between the power source and tool. This substitution transmits rotary motion effectively while eliminating the oscillations that arise from the flexibility and elasticity of belt materials, thereby improving thread surface precision.
4Power
If gears are used to drive the threading tool, then rotary motion can be transmitted, but clearances are necessary for proper meshing that negatively affect precision
Solution Approach 1:
The patent replaces the gear transmission system with a direct electromagnetic coupling. The brushless synchronous motor's rotor is directly coupled to the tool spindle, eliminating the gear meshing mechanism entirely. This substitution maintains full power transmission capability while removing the clearances that are necessary for gear meshing but that negatively impact precision, thereby improving thread surface quality.
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 enhances precision and reduces size and maintenance needs, providing high-quality threads without machining defects and allowing for precise control without speed sensors, resulting in a more efficient and reliable threading process.
Implementation Method 1
an electric rotor (9) to which an electric stator (8) built-in in said supporting assembly is operatively coupled
Implementation Method 2
said stator (8) may have a stator outer circumference including a plurality of channels for circulating therethrough a refrigerating fluid
Implementation Method 3
the electric stator (8) may be encompassed by a sleeve (7) having a plurality of circumferential channels, therethrough a refrigerating and lubricating fluid flows
Data Source
Figure 1
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AI summary
A piece-threading device on a numerically controlled lathe comprises a supporting assembly having an inner rotatively driven body which, on a side thereof facing a workpiece to be threaded, comprises a plurality of threading tools, the rotatively driven body having a built-in electrical rotor (9) to which an electric stator (8) also built-in in the supporting assembly is operatively coupled, the stator (8) having a plurality of circumferential channels (6) for circulating therethrough a refrigerating and lubricating fluid.