Eccentric Boring Bar with Segmented Guide Elements
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Solution Overview
Problem
Existing rotating cutting tools, such as boring bars, face challenges in machining bores spaced apart in the axial direction due to the complexity of supporting the cutting edges and guide elements, which can lead to damage during retraction and require intricate mechanical arrangements.
Innovation Solution
A cutting tool design featuring a basic body with cutting elements and guide elements positioned in an equivalent cutting and guide radius, allowing for eccentric insertion and support, enabling reliable machining of bores with direct support at the cutting edge while preventing surface damage upon removal, and incorporating a balancing element to reduce imbalance and enhance concentricity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If cutting edges and guide elements are arranged offset in the radial direction to enable boring bar insertion through rough bores, then the boring bar can be inserted through rough bores, but the arrangement requires a moving, mechanically complex structure and risks damaging the machined bore surface during retraction
Solution Approach 1:
The boring bar is divided into functionally independent segments: cutting elements at working positions and guide elements at a separate guide position. This segmentation allows each element to perform its specific function without requiring complex mechanical linkages between them, simplifying the overall structure while maintaining insertion capability.
Solution Approach 2:
A guide bore is introduced as an intermediary element that receives the guide elements of the boring bar. This guide bore acts as a mediator that guides the boring bar during insertion and retraction, eliminating the need for complex mechanical arrangements to control the relative positions of cutting and guide elements.
2Ease of operation
If cutting edges and guide elements are arranged offset in the radial direction, then the boring bar can be inserted through rough bores, but reliable retraction with radial extension requires complex mechanical arrangements and assurance of non-damaging retraction
Solution Approach 1:
The boring bar structure separates guide elements from cutting elements both axially and radially. This segmentation allows the guide elements to remain stationary relative to the boring bar body during retraction, while cutting elements can be independently positioned, ensuring reliable retraction without surface damage.
Solution Approach 2:
The guide bore serves as an intermediary that controls the retraction path of the boring bar. By guiding the boring bar through the guide bore, the system ensures that the boring bar retracts along a controlled path that prevents damage to the machined bore surface.
3Productivity
If multiple cutting edges are arranged axially spaced to machine multiple bores simultaneously, then productivity increases, but the boring bar length increases making handling and support more difficult
Solution Approach 1:
Instead of arranging cutting elements only in the axial direction, the invention utilizes both axial and radial dimensions for element arrangement. Cutting elements are positioned at different axial locations while guide elements are positioned radially offset at a specific axial position, creating a two-dimensional arrangement that improves productivity without proportionally increasing bar length.
Solution Approach 2:
The boring bar design integrates multiple functions into a single tool: multiple cutting edges for machining different bores, guide elements for positioning and guidance, and balanced mass distribution for vibration reduction. This multi-functionality allows the bar to maintain reasonable length while achieving high productivity through simultaneous bore machining.
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 simplifies the machining process by allowing eccentric retraction and central machining, ensuring precise support during cutting and preventing surface damage, while also reducing vibrations and improving concentricity through balanced mass distribution.
Implementation Method 1
incorporating a balancing element to reduce imbalance and enhance concentricity
Data Source
AI summary
To make it possible for bores (16) that are in line with one another to be efficiently worked by means of a boring bar (2), the boring bar has a main body (10) with an axis of rotation (R) and a number of cutting elements (12, 12A) at intervals from one another in the axial direction (4) and also guiding elements (14) for guiding the main body (10) in a guiding bore (16A). The guiding elements (14) are kept at a distance from the axis of rotation (R) equivalent to a guide radius (r1). The main body (10) is divided into a functional region (19) and an eccentric region (10), wherein the cutting elements (12, 12A) and the guiding elements (14) are arranged such that they are distributed around the main body (10) over an angular range (a) of less than 180°. Furthermore, the circumferential side (22) of the main body (10) can be passed eccentrically through a respective bore (16, 16A) of which the unworked tube radius (r2) is less than the guide radius (r1).