Extended Boring Bar Coupling With Zero-Point Positioning Rigidity
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Solution Overview
Problem
Existing turning and milling composite machine tools face challenges in machining deep inner holes due to the need for repeated clamping, which affects precision and efficiency, and existing connection mechanisms for extended boring bars lack rigidity and vibration-reduction measures.
Innovation Solution
An extended boring bar connecting apparatus using zero-point positioning mechanisms, featuring hydraulic expansion sleeves and multiple vibration-reduction structures, ensures high-clamping rigidity and precision by locking a boring bar seat to a power spindle box and incorporating angular and axial positioning, along with various vibration-reduction mechanisms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a dovetail groove locking mechanism is used to connect the extended boring bar to the power tool spindle box, then the connection structure is simple, but the connection rigidity is reduced due to many connection links
Solution Approach 1:
The connection system is segmented into two independent parts: the dovetail groove mechanism for simple installation and the auxiliary positioning blocks for enhanced rigidity. This segmentation allows each component to fulfill its specific function without compromising the other, resolving the contradiction between structural simplicity and connection rigidity.
Solution Approach 2:
The connection mechanism combines two different structural approaches (dovetail groove and auxiliary positioning blocks) into a composite system. This composite structure leverages the advantages of both mechanisms to achieve both ease of manufacture and high connection rigidity simultaneously.
2Device complexity
If traditional screw pressing mode is used to clamp the boring bar, then the structure is simple, but the clamping rigidity is insufficient
Solution Approach 1:
The patent employs a hydraulic expansion sleeve that uses hydraulic pressure to expand and clamp the boring bar. This hydraulic mechanism provides significantly higher clamping rigidity compared to traditional screw pressing, while maintaining relatively simple structural implementation through the expansion sleeve design.
3Productivity
If the extended boring bar is directly loaded onto the power tool spindle, then the machining efficiency is high, but the tool cannot be loaded due to excessive length and weight
Solution Approach 1:
The extended boring bar seat assembly serves as an intermediary component between the power tool spindle and the extended boring bar. This intermediate structure enables the loading of long, heavy boring bars that cannot be directly loaded onto the spindle, while still maintaining high machining efficiency through the integrated connection system.
4Manufacturing precision
If workpiece is transferred to another dedicated device for sequential machining of deep inner holes, then the machining capability is achieved, but the machining cycle increases and machining precision is affected due to repeated clamping
Solution Approach 1:
The turning and milling composite machine tool is enhanced with multi-functionality through the extended boring bar system, enabling it to perform deep hole machining that was previously requiring separate dedicated devices. This eliminates the need for workpiece transfer and repeated clamping, thereby maintaining high machining precision and reducing the machining cycle.
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
The apparatus achieves high-precision and efficient machining of deep holes with enhanced rigidity and reduced vibration, allowing for seamless adaptation of different length-to-diameter boring bars without custom interfaces and facilitating automatic exchange.
Implementation Method 1
two hydraulic expansion sleeves 18, 21 are arranged in inner holes of a boring bar seat 17, and have dimensions corresponding to a diameter of an excircle where an extended boring bar 27 is clamped
Implementation Method 2
a plurality of vibration-reduction structures are also designed in the connecting apparatus, and can reduce the cutting vibration of an extended boring bar
Data Source
AI summary
The present invention discloses an extended boring bar connecting apparatus based on zero-point positioning mechanisms. A side surface of a power spindle box assembly is used as a connection base surface of a boring bar seat assembly, and an extended boring bar assembly is clamped in inner holes of hydraulic expansion sleeves of the boring bar seat assembly, and is also connected to a power spindle tool interface in the power spindle box assembly. A boring bar seat is locked to the side surface of the power spindle box assembly through zero-point positioning mechanisms. Two hydraulic expansion sleeves are arranged in an inner hole of the boring bar seat, and have dimensions corresponding to the diameter of an excircle where a boring bar is clamped. A tool holder interface flange of the boring bar assemblies is locked to the power spindle box assembly.