Spindle Torque Evening-Out for Precision Drilling-Milling
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Solution Overview
Problem
Drilling-milling devices face challenges in achieving high cutting capacity and surface quality, with limited operational and service life, due to inefficiencies in torque and rotational velocity management.
Innovation Solution
Incorporating a flywheel mass with adjustable mass distribution and a braking mechanism to even out torque and rotational velocity, controlled by sensors and a feedback loop, which optimizes machining quality and tool life.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a gear mechanism is used to transmit power from the drive shaft to the spindle, then the drilling-milling device can achieve versatile tool orientations and angles, but the torque and rotational velocity become uneven, reducing machining quality and tool life
Solution Approach 1:
The flywheel mass is positioned upstream in the power transmission path to preemptively smooth out torque and rotational velocity variations before they reach the spindle. This preliminary action of energy storage and release prevents the uneven motion from affecting machining quality, while still allowing the gear mechanism to provide versatile tool orientations.
2Adaptability or versatility
If a gear mechanism is used to transmit power from the drive shaft to the spindle, then the drilling-milling device can achieve versatile tool orientations and angles, but the operational life and service life are significantly reduced
Solution Approach 1:
The flywheel mass smooths torque variations before they reach the spindle and tool, preventing sudden load spikes that would otherwise accelerate tool wear and reduce operational life. This preliminary smoothing action extends tool life while maintaining the gear mechanism's versatility for different tool orientations.
Solution Approach 2:
The flywheel mass acts as a cushioning element that absorbs and releases energy to compensate for torque fluctuations. This beforehand cushioning effect protects the tool and spindle from harmful torque variations, extending their operational life while preserving the gear mechanism's ability to achieve versatile tool orientations.
3Manufacturing precision
If flywheel mass is increased to even out torque and rotational velocity, then machining quality improves, but the device complexity and space requirements increase
Solution Approach 1:
Instead of uniformly increasing the entire spindle's mass, the invention concentrates the flywheel mass specifically in the regions that contribute most to the mass moment of inertia. This local quality approach smooths torque variations and improves machining quality while minimizing the overall increase in device complexity and space requirements.
Solution Approach 2:
The invention uses materials with high relative density (such as lead, tantalum, or tungsten) for the flywheel mass. These composite material choices enable achieving the desired mass moment of inertia in very compact dimensions, improving machining quality without significantly increasing device complexity or occupying excessive space.
4Volume of moving object
If materials with high relative density are used to achieve large mass moment of inertia in compact dimensions, then the device size is reduced, but the manufacturing complexity and cost increase
Solution Approach 1:
The invention adjusts the mass distribution parameters of the flywheel mass by using high relative density materials. This parameter change enables achieving the required mass moment of inertia in compact dimensions, reducing the overall device size. The manufacturing complexity is managed by integrating the flywheel mass into the existing spindle structure and using materials that can be machined or formed into the required geometries.
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
Significantly enhances machining quality and extends the operational life of cutting tools and drilling-milling devices by ensuring consistent torque and reduced backlash, improving precision and efficiency.
Implementation Method 1
The desired large mass moment of inertia of the spindle or of the flywheel mass can be achieved by means of the geometry of the spindle and the flywheel mass
Implementation Method 2
In a second, preferred embodiment, the desired evening-out is achieved by means of a brake that is coupled to the spindle and transmits the braking torque to the housing of the drilling-milling device
Data Source
AI summary
A drilling-milling device comprising a housing; a drive shaft; a spindle; and a brake. The drive shaft and the spindle being coupled to one another by a gear mechanism, and the brake being coupled to the spindle and a braking torque of the brake being transmitted to the housing.