Inner-cooling drill bit applied to machining of through hole including step countersink

Abstract

The invention relates to an inner cooling drill bit applied to machining of a through hole including a step countersink. The inner-cooling drill bit comprises a drill bit, a butterfly-shaped spring sheet and a blocking plug, and is characterized in that: the drill bit is provided with four cooling holes which are used for cooling a main cutting edge and a secondary cutting edge respectively; the handle of the drill bit is provided with a main liquid charging channel hole; the butterfly spring sheet and a valve core are arranged inside the main liquid charging channel hole; the valve core can move in a reciprocating way under the action of cooling liquid pressure and the butterfly spring sheet, the shunting of the cooling liquid is realized through the opening and closing of different cooling channels. By adopting the drill bit, secondary drilling process is performed in order to pass through the cooling channel, and the cooling channel is blocked with plungers; when the main cutting edge works, the secondary cutting edge is not cooled, full cooling of the cooling liquid to the edges is ensured; when the secondary cutting edge works, the cooling liquid is used for cooling the secondary cutting edge and the main cutting edge simultaneously, and cooling effect for the secondary cutting edge is ensured. The drill bit main liquid charging channel is provided with a pressure-releasing channel, is communicated with the main edge cooling channel, and plays a role in releasing pressure.

Description

technical field [0001] The present invention relates to a drill bit, in particular to a drill bit for through-hole processing including stepped counterbore. Background technique [0002] Through-hole processing is a common form of drilling, which requires the tip of the drill bit to extend out of the material being drilled. Common drills only have 2 internal cooling holes on the flank of the drill. As for the through hole with stepped counterbore, since the counterbore processing generally has a drilling depth of less than 5mm, the hole is reamed on the basis of the already drilled hole, and the cutting allowance is small, so it is often used as a secondary processing content. In order to improve the drilling efficiency , Place the cutting edge for machining the counterbore on the drill bit for drilling the main hole to form a composite drill bit, which can complete the main hole and the counterbore in one process. However, the cutting edge of the counterbore is generally ...

AI Technical Summary

Problems solved by technology

However, the cutting edge of the counterbore is generally not cooled by coolant. If cooling holes are added, the coolant will be diverted and the coolant flow rate will be reduced, which is not conducive to the cooling of the main cutting edge.

The cutting edge of the counterbore is dry cutting, the blade wears quickly, and the cutting force increases rapidly, resulting in a decrease in the overall life of the tool

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