Built-In Spindle Drive With Clutch Chuck Actuation
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Solution Overview
Problem
Conventional machine tools with hydraulic driving systems face issues such as slow response speed, difficulty in precisely controlling chuck clamping force, and inefficiencies due to belt-driven power transmission, which are not adequately addressed by existing electric-driven spindle systems that still rely on belts for power transfer.
Innovation Solution
A built-in type electric driving system that directly connects a motor to the spindle without a belt, using a clutch device to transfer power to both the spindle and drawbar, and includes a chuck locking unit, clutch unit, lead screw, and driving unit to enable precise control of the workpiece clamping and rotation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a belt-driven system is used to transmit power from motor to spindle, then the structure is simple and easy to implement, but friction between belt and pulley causes efficiency degradation, noise, vibration, and maintenance problems
Solution Approach 1:
The patent removes the belt transmission component from the system entirely. The motor is directly integrated with the spindle, eliminating the intermediate belt and pulley components that cause friction, noise, and energy loss. This direct-drive configuration extracts the problematic transmission elements while maintaining the essential power transmission function.
Solution Approach 2:
The motor and spindle are merged into a single integrated unit. The motor's rotor is directly coupled to the spindle, combining what were previously separate components (motor assembly and spindle assembly) into one unified structure. This merging eliminates the need for external power transmission mechanisms like belts.
2Force
If a hydraulic system is used to drive the drawbar and chuck, then the clamping force can be generated, but the response speed is slow and precise control of clamping force is difficult
Solution Approach 1:
The patent replaces the hydraulic system with an electric system. The motor that drives the spindle also provides power to the drawbar through a direct mechanical connection (such as a gear mechanism or direct coupling). This substitution of hydraulic actuation with electric-mechanical actuation enables faster response and more precise control through electronic feedback systems.
Solution Approach 2:
The motor serves multiple functions: it drives both the spindle rotation and the drawbar movement. By making the motor a universal power source for both functions, the system eliminates the need for separate hydraulic systems, reducing complexity and improving response time through centralized electronic control.
3Ease of manufacture
If independent driving systems are used for drawbar and spindle, then each component can be optimized independently, but the overall device complexity increases
Solution Approach 1:
The motor is designed to perform multiple functions simultaneously - driving both the spindle rotation and the drawbar movement. This multi-functionality reduces the number of independent driving systems needed, simplifying the overall system while still allowing independent optimization of each function through separate control mechanisms.
Solution Approach 2:
The patent combines the driving functions for the spindle and drawbar into a single motor unit. Rather than having separate motors or hydraulic systems for each component, the integration merges these functions, reducing the number of components and simplifying the overall system architecture while maintaining independent controllability.
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 allows for efficient clamping and unclamping operations without belts, simplifying the machine tool's configuration and operation by using a built-in motor to drive both the spindle and chuck, thereby overcoming the inefficiencies and limitations of traditional systems.
Implementation Method 1
a built-in motor consisting of a stator fixed to the inside of the housing and a rotor fixed to an outer surface of the spindle, and configured to generate torque between the stator and the rotor by power applied from the outside to cause rotation of the rotor
Implementation Method 2
a lead screw formed with a thread in a spiral shape on an outer surface thereof, and formed to be fixed to the drawbar; a female screw cover coupled to the driving unit to rotate together with the driving unit, and having a thread formed on an inner circumferential surface thereof to be screw-coupled to the thread of the lead screw
Data Source
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AI summary
The present invention relates to a built-in type electric driving system of a machine tool. The system may comprise: a housing; a hollow tube-shaped spindle extending in the forward/backward direction with respect to the housing and installed to be able to rotate with regard to the housing; a built-in motor comprising a stator fixed inside the housing and a rotor fixed to the outer surface of the spindle and generating a torque between the stator and the rotor by externally applied power to rotate the rotator; a chuck installed at the front end of the spindle and including a jaw for gripping an object to be processed; a drawbar installed inside the spindle to linearly move the forward/backward and having a front end connected to the jaw; a drawbar key and a drawbar key groove, which connect the drawbar to the chuck such that the drawbar can linearly move, but cannot rotationally move; a chuck locking unit for restricting or releasing a rotational movement of the chuck with regard to the housing; a clutch unit installed to move forward/backward between the front portion of the spindle and the rear portion of the chuck so as to restrict the spindle to the chuck or separate the spindle in a rotatable manner relative to the chuck; a leadscrew formed to be fixed to the drawbar and having a thread helically formed on the outer surface thereof; a driving unit fixed to the outer surface of the spindle so as to rotate together with the spindle; and a female screw cover coupled to the driving unit so as to rotate together with driving unit, and having a thread formed on the inner peripheral surface thereof so as to be screw-coupled to the thread of the leadscrew.