Independent Spindle Boring Bar Wobble for Precision
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Solution Overview
Problem
Existing spindle boring methods face inaccuracies due to movements of masses and mass oscillations, leading to disruptive factors that affect the generation of non-round bores in workpieces, such as those required for internal combustion engine pistons.
Innovation Solution
The method employs two independently controllable spindle units with a boring bar that undergoes a wobbling movement due to opposite rotations of its ends, eliminating the need for spindle axis inclination and components like connecting rods or hydraulic adjustments, thereby avoiding vibrations and inaccuracies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional spindle boring methods with hydraulic adjustments and connecting rods are used, then spindle axis inclination can be achieved, but movements of masses and mass oscillations occur causing vibrations and inaccuracies
Solution Approach 1:
The patent removes the connecting rods, levers, and hydraulic adjustment devices from the system. By eliminating these intermediate components, the transmission of movements of masses and mass oscillations to the spindle axis is prevented, thereby reducing vibrations and improving boring accuracy without requiring spindle axis inclination mechanisms
Solution Approach 2:
The patent replaces the mechanical hydraulic adjustment system with a direct digital control system that actuates the spindle units independently. This substitution eliminates the need for pressure lines, pistons, and mechanical linkages that cause mass movements and oscillations, thereby reducing vibrations while maintaining adjustment capability
2Ease of operation
If pressure-adjustable drill heads are used to deflect the tool carrier, then radial adjustment can be achieved, but pressure fluid supply and mass displacement are required causing time delays and vibrations
Solution Approach 1:
The patent replaces the hydraulic pressure fluid supply system with a direct digital control system that independently actuates each spindle unit. This eliminates pressure lines, pistons, and mechanical linkages, thereby eliminating time delays associated with fluid compression and transmission while maintaining full radial adjustment capability through direct motor control
3Manufacturing precision
If piezoelectric servomotors are used to deflect the lathe tool, then fine adjustment can be achieved, but temperature changes and disruptive factors require complicated electronic monitoring
Solution Approach 1:
The patent divides the boring system into two independently controllable spindle units, each capable of independent adjustment. This segmentation eliminates the need for a single complex servomotor system with electronic monitoring, as each spindle unit can be directly controlled by simple drive mechanisms without requiring compensation for temperature changes or disruptive factors
Solution Approach 2:
The independent spindle units self-adjust to maintain precision through their own drive mechanisms without requiring external electronic monitoring systems. Each spindle unit operates autonomously, eliminating the need for complicated temperature compensation and disruption correction electronics
Data Source
Figure 1
Figure 2~3
Figure 4~6
AI summary
The drill for out-of-round drilling has two spindle units (1,2), controlled independently of each other to give a mantle line run. The ends (3,4) of the tool carrier (5) follow opposing paths to give a tumble movement to the tool (6) to machine the workpiece (7). The tool carrier ends follow circular paths of different diameters, so that the tool follows an elliptical mantle line path. Only one end (3) is clamped radially and axially at a spindle unit (1) while the other end (4) is simply mounted in a central drilling (10) of the other spindle unit (2) tool holder.