Machine Tool Drawbar Drive with Encoder-Guided Clutch Alignment
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Solution Overview
Problem
Existing machine tools with hydraulic drawbar systems face complications in driving units, inefficient force control, and inaccuracies in engaging clutch serrations during mode switches, leading to vibrations and processing defects.
Innovation Solution
An electrical driving system with a position detection unit and controller that accurately aligns clutch serrations by detecting spindle positions in real time, using a motion conversion unit to convert rotary motion into linear motion, and a clutch unit to selectively connect the spindle to a drive pulley, ensuring precise engagement of serrations during mode transitions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a hydraulic system is used to operate the drawbar, then the driving unit can be simplified, but the chuck cannot control the force to hold the workpiece and efficiency is low
Solution Approach 1:
The patent replaces the hydraulic system with an electrical system. Specifically, an electric motor (spindle motor) is used to rotate the drive pulley, which through the lead screw mechanism, drives the drawbar. This substitution eliminates the need for hydraulic components while providing precise force control through electrical means, thereby simplifying the driving unit structure and improving reliability.
2Ease of operation
If the spindle operation mode is switched to clamping operation mode without position detection, then mode switching is simple, but the serration may not be correctly engaged causing vibrations and noises
Solution Approach 1:
The patent introduces a position detection unit (encoder) that detects the rotational position of the drive pulley and provides feedback to the controller. When switching from spindle operation mode to clamping operation mode, the controller uses this feedback information to accurately determine the position of the serration and control the clutch unit to engage at the correct position, thereby avoiding vibrations and noises while maintaining simple mode switching operation.
3Manufacturing precision
If real-time position detection is implemented to align clutch serrations, then serration engagement accuracy is improved, but device complexity increases
Solution Approach 1:
The patent introduces a position detection unit (encoder) as an intermediary component between the drive pulley and the controller. This encoder detects the rotational position and transmits this information to the controller, which then uses it to precisely control the clutch unit's engagement position. This intermediary mechanism enables high precision serration engagement without requiring complex control algorithms or additional mechanical positioning mechanisms.
4Adaptability or versatility
If the clutch unit is designed to selectively connect spindle and drive pulley, then operational versatility is improved, but device complexity increases
Solution Approach 1:
The clutch unit is designed as a multi-functional component that can selectively connect the spindle to the drive pulley for spindle operation mode and disconnect for clamping operation mode. This single clutch mechanism handles both operational modes, eliminating the need for separate transmission paths for each mode. The clutch unit's ability to perform both connection and disconnection functions within a single component structure provides operational versatility while minimizing the increase in device 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
Ensures accurate engagement of clutch serrations, reducing vibrations and processing defects by aligning serrations based on real-time position detection, thereby improving operational efficiency and control in machine tools.
Implementation Method 1
a timing belt wound around the first encoder pulley and the second encoder pulley to transmit a rotational force of the first encoder pulley to the second encoder pulley
Implementation Method 2
a lead screw to replace the existing hydraulic system with an electric system
Data Source
AI summary
A machine tool electrical driving system includes a housing, a hollow tubular spindle rotatably installed inside the housing, a drive pulley rotatably installed with respect to the spindle outside the spindle, a spindle motor, a drawbar installed to be linearly movable with respect to the spindle but non-rotatable relative to the spindle, a motion conversion unit configured to convert a rotary motion of the drive pulley into a forward-rearward linear motion of the drawbar, a clutch unit, a position detection unit configured to the drive pulley to detect an amount of rotation and a rotation position of the drive pulley, and a controller.