Fork-Mounted Spindle Head With Dual Actuators for Zero-Clearance Oscillation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing spindle-mounting heads for machine tools in the aeronautics and aerospace sectors face challenges in achieving high precision, minimizing clearances, and maintaining structural and thermal symmetry while maintaining compact dimensions, as previous solutions either suffer from high friction and wear due to intrinsic clearances or are bulky and complex.
Innovation Solution
A spindle-mounting head design featuring a fork-shaped structure with two actuator units, each comprising a rotary motor and reduction gear unit, with bevel gears and a master-slave control system to generate unbalanced torques, eliminating clearances and optimizing oscillation control for balanced structural and thermal performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a screw-gear coupling is used to transmit motion between motor and spindle, then the system is inexpensive and generally not bulky, but clearances are present which lead to increased friction, critical issues in machining speed and wear
Solution Approach 1:
The patent replaces the traditional mechanical screw-gear coupling with a direct electromagnetic coupling where the torque motor is integrated directly with the spindle. This eliminates the intermediate mechanical transmission elements (screws, gears, belts) that inherently contain clearances, thereby removing the source of friction and wear while maintaining compact dimensions and low cost.
Solution Approach 2:
The patent merges the motor and spindle into a single integrated unit, where the torque motor is directly coupled to the spindle shaft. This consolidation eliminates the need for separate transmission components and their associated clearances, achieving both compactness and high reliability simultaneously.
2Measurement precision
If a cascade of gear wheels with preloading system is used to transmit motion, then maximum operating precision is achieved, but the system is bulky and structurally complex with limited transmissible torque
Solution Approach 1:
The patent replaces the complex cascade gear system with a direct-drive electromagnetic coupling. The torque motor generates rotational force directly on the spindle shaft without mechanical intermediaries, eliminating the need for multiple gear stages, preloading mechanisms, and clearance compensation systems, thereby achieving precision without complexity or bulk.
Solution Approach 2:
The patent segments the traditional transmission system into a simplified integrated unit where the motor and spindle function as a unified assembly. This segmentation removes unnecessary intermediate components (gear wheels, preloading systems) and retains only the essential functional elements, reducing complexity while maintaining precision.
3Speed
If the spindle is coupled directly to an electric motor/torque motor, then high dynamic level free of clearances is achieved, but high torques cannot be generated keeping the dimensions of the head reduced
Solution Approach 1:
The patent changes the key parameter of the motor-spindle coupling from mechanical transmission to direct electromagnetic coupling. This parameter change enables the system to generate high torques through electromagnetic force directly at the spindle shaft while maintaining compact dimensions and high dynamic response, as the electromagnetic field can produce force without mechanical leverage limitations.
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 design achieves high precision, minimizes clearances, and maintains a compact size by balancing structural and thermal aspects, enabling high dynamic motion with high torque transmission while reducing overall dimensions and optimizing mass and force distribution.
Implementation Method 1
Each actuator unit comprises a rotary motor configured to generate a drive torque
Implementation Method 2
a reduction gear unit coupled to said rotary motor and configured to provide to an outlet shaft a transmitted torque greater than the drive torque
Implementation Method 3
there is a bevel gear equipped with a first wheel keyed on said outlet shaft and a second wheel constrained to said spindle and coaxial with said axis of oscillation
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
Described is a spindle mounting head for a machine tool comprising a supporting body (2) comprising at least a first arm (3) and a second arm (4) protruding from a base portion (5) and defining a fork-shaped structure, a tool-mounting spindle (6) at least partly housed in the fork-shaped structure and rotatably connected to the arms (3, 4) for rotating about an axis of oscillation (A) and movement means (7) operatively interposed between the supporting body (2) and the spindle (6) for rotating it about the axis of oscillation (A). The movement means (7) comprise a first actuator unit (8) and a second actuator unit (9) housed, respectively, in the first arm (3) and in the second arm (4).