Bi-rotating Machining Head with Motor-Driven Electrospindle
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Solution Overview
Problem
Existing bi-rotating machining heads face limitations in maintaining precision and stiffness when machining irregular surfaces, as floating devices wear out and lose contact force when tilted, leading to machining errors due to varying vertical weight components.
Innovation Solution
A bi-rotating machining head with an electrospindle unit that includes a motor and tool holder, capable of linear sliding movement to maintain constant contact force and position, compensating for surface irregularities by adjusting the entire spindle unit, including the motor, to ensure precise machining on non-nominal shapes and dimensions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a floating device with contrasting springs is used to compensate for surface irregularities, then the tool can adapt to non-regular workpiece surfaces, but the device loses stiffness and precision when tilted due to varying vertical weight components
Solution Approach 1:
The patent replaces the mechanical spring-based floating device with a motor-driven electrospindle unit. The motor (21) drives the tool holder (4) through a transmission system, eliminating reliance on spring force and gravitational vertical components. This substitution maintains precision regardless of tilt angle because the motor provides active control rather than passive mechanical compensation.
Solution Approach 2:
The electrospindle unit introduces dynamic control capability where the motor can actively adjust and maintain the desired vertical distance between the tool and workpiece surface. Unlike the static spring-based system, the motorized system can dynamically compensate for surface irregularities while maintaining constant contact force and machining precision even when tilted.
2Adaptability or versatility
If a floating device is used to compensate for surface irregularities, then the tool can follow the workpiece contour, but the device is subject to wear and formation of excessive clearance over time
Solution Approach 1:
The patent replaces the wear-prone mechanical floating device with a motor-driven system. The motor (21) and transmission mechanism eliminate sliding contacts and friction-based compensation, thereby preventing wear and clearance formation. The belt transmission and motor coupling provide reliable, maintenance-free operation over time while maintaining contour following capability.
3Adaptability or versatility
If the floating device operates on tilted surfaces, then the tool can reach irregular zones, but the vertical component of weight varies significantly causing loss of contact force
Solution Approach 1:
The patent replaces the gravity-dependent spring system with a motor-driven system where the motor (21) actively controls the tool holder position. The motor provides sufficient driving force to maintain contact with the workpiece regardless of tilt angle, eliminating the problem of varying vertical weight components. The transmission system transfers motor force efficiently to maintain constant contact force in all orientations.
Data Source
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AI summary
A bi-rotating machining head is disclosed that is operationally associated with a machining centre with five controlled axes, with an axis control unit that carries an electrospindle unit that drives a tool holder, with abutting means fitted rotatably to the tool holder to abut on a workpiece and to maintain a desired relative position between the workpiece and the tool, in which possible irregularities of the surface of the workpiece are compensated through the effect of a linear sliding movement of the electrospindle unit with respect to the aforesaid axis control unit.