Drill Body Fluid-Hole Layout for Coolant Flow and Tip Stiffness
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Solution Overview
Problem
Existing drill designs face challenges in effectively supplying cutting fluid to the cutting region while maintaining stiffness, especially when a removable cutting edge member is mounted, as the leading end part requires both fluid supply and structural integrity.
Innovation Solution
A drill body design featuring a fluid hole with a changing cross-sectional shape from circular to non-circular, longer in the circumferential direction, which passes through an inter-groove solid part, and a recessed mounting part for the cutting edge member, allowing efficient fluid flow and maintaining stiffness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a flow hole is provided inside the drill body to supply cutting fluid to the cutting region, then cutting fluid supply is improved, but stiffness of the leading end part deteriorates
Solution Approach 1:
The flow hole cross-sectional shape is changed locally along its length. In the leading end part where stiffness is critical, the flow hole has a non-circular cross-section (with a flat side or reduced area) to maintain structural strength. In other portions where stiffness is less critical, the flow hole has a larger cross-sectional area to improve cutting fluid supply capacity. This local variation in geometry resolves the contradiction between fluid supply and stiffness.
2Ease of repair
If a mounting part is provided in the leading end part for mounting a removable cutting edge member, then cutting edge replacement is improved, but stiffness of the leading end part deteriorates
Solution Approach 1:
The flow hole cross-section is designed with asymmetry, particularly with a flat side or reduced area on the side where the mounting part is located. This asymmetric design allows the mounting part to be integrated without significantly compromising the overall stiffness of the leading end part, while still providing adequate space for cutting edge member mounting and replacement.
3Quantity of substance
If the flow hole cross-sectional area is increased to improve cutting fluid supply, then fluid flow is improved, but stiffness of the drill body deteriorates
Solution Approach 1:
The flow hole is segmented into different sections along its length, with each section having an optimized cross-sectional area. The section in the leading end part has a smaller cross-sectional area to maintain stiffness, while downstream sections have larger cross-sectional areas to improve cutting fluid supply capacity. This segmentation allows the drill body to achieve both stiffness and adequate fluid flow.
Data Source
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AI summary
A drill body (100) is provided which includes a flow hole capable of appropriately supplying a cutting region with a cutting fluid while securing stiffness of a leading end part. The drill body (100) includes: a body part (110) which extends in a rod shape from a base end part toward a leading end part (112); a discharge groove (113) which is provided around a central axis (P) of the body part in order to discharge chips; a fluid hole which is provided such that at least a part thereof passes through an inside, of the body part, of an inter-groove solid part of the discharge groove and which causes a fluid to flow from a side of the base end part toward a side of the leading end part; and a mounting part (120) which is provided in the leading end part (112) and which is for mounting a removable cutting edge member (200), wherein the mounting part has a recessed part which is provided along the central axis of the body part from an end surface of the leading end part, and a hole cross section of the fluid hole changes from a circular shape to a non-circular shape (131, 141) which is longer in a circumferential direction than in a radial direction in an axial cross section of the body part midway along a path of the fluid hole from the base end part toward the leading end part and assumes a non-circular shape in a portion which passes a side part of the recessed part.