CN202894424U

CN202894424U - Drill bit capable of reducing bore wall roughness of borehole

Info

Publication number: CN202894424U
Application number: CN 201220398043
Authority: CN
Inventors: 刘含钦
Original assignee: SHANXI GUANLI FLANGE CO Ltd
Current assignee: Shanxi Guanli Flange Co ltd
Priority date: 2012-08-13
Filing date: 2012-08-13
Publication date: 2013-04-24
Anticipated expiration: 2022-08-13

Abstract

The utility model discloses a drill bit capable of reducing the bore wall roughness of a borehole, relates to normal drill bits, and solves the technical problem that the bore wall roughness of the borehole drilled by an existing normal standard drill bit is high. The drill bit capable of reducing the bore wall roughness of the borehole is manufactured by grinding cutting blades of the normal standard drill bit into eudipleural step shape to form a first cutting blade and a second cutting blade, the first cutting blade is parallel to the second cutting blade, and the distance between the tip tops of two cutting blades is 8 mm. The relief angle of the second cutting blade is 25 degrees, the relief angle of the first cutting blade and the relief angle of an arc portion between the first cutting blade and the second cutting blade are both 15 degrees, the rake angles of the first cutting blade and the second cutting blade are 5 degrees, and the cross blade of the drill bit is 2.3 mm to 2.6 mm. The drill bit capable of reducing the bore wall roughness of the borehole is used for drilling large diameter holes of galvanized anticorrosion flanges, cutting force is reduced by about 30%, cutting friction is also reduced, the bore wall is smooth and burr-free, and the roughness is up to Ra6.3.

Description

A kind of drill bit that reduces the borehole wall roughness

Technical field

The utility model relates to common upright drill drill bit, particularly a kind ofly bores major diameter and requires the smooth target drill of hole wall.

Technical background

During common upright drill Application standard Twist Drill, when particularly boring large diameter hole, because cutting force is bigger than normal, can cause drill press spindle to creep, feeding is uneven, and is bigger than normal because of cutting force simultaneously, the heat in metal cutting that produces is also many, and is particularly when boring the low-carbon (LC) steel part, many because cutting heat, smear metal viscosity is large, and toughness is high, is difficult for chip breaking, chip removal is not smooth, hole wall is squeezed pulls groove to occur, and a large amount of burr, roughness is very poor.For the flange that the galvanized anticorrosive requirement is arranged, its bolt hole roughness require to reach Ra6.3, common drill bit is difficult to reach standard-required.For satisfying the requirement of bolt hole roughness, generally adopt twice boring method (two kinds of different drill bits of diameter are holed at twice), but this method process-cycle prolong nearly one times, processing cost is high, should not produce in enormous quantities.

Summary of the invention

The purpose of this utility model is to overcome existing technical disadvantages, and a kind of drill bit that reduces the borehole wall roughness is provided, and solves the existing high technical problem of common standard bit bore Hole Wall Roughness.

The utility model is achieved through the following technical solutions:

A kind of drill bit that reduces the borehole wall roughness, it is characterized in that: described drill bit is that the cutting edge of common standard drill bit is worn into symmetrical step shape, form the first cutting edge and the second cutting edge, described the first cutting edge distance parallel with the second cutting edge and the two-edged pinnacle is 8mm; The relief angle of described the second cutting edge is 25 °, and the relief angle at the arc place between the relief angle of described the first cutting edge and described the first cutting edge and the second cutting edge is 15 °; The anterior angle of described the first cutting edge and the second cutting edge is 5 °; The chisel edge length of described drill bit is 2.3～2.6mm.

The utility model compared with the prior art, its advantage and effect are as follows:

Because the utility model is that the common standard drill bit is carried out sharpening, change its cutting edge parameter and shape, namely about two cutting edges wear into step, form by " the first cutting edge " and " the second cutting edge ".The parallel certain distance that keeps again of two cutting edges is equivalent to two different drill bits of diameter and successively participates in cutting, produces the effect of twice boring; Owing to shortened described chisel edge length b, to reduce cutting force, strengthened described bit cutting edge clearance angle α ₁, to reduce drill bit and friction of workpiece power, suitably strengthen described drill bit anterior angle γ, make chip deformation curling easily, chip removal is unobstructed, has eliminated the smear metal obstruction and has pulled the hole wall phenomenon.The utility model be used for to bore the large diameter hole of galvanized anticorrosive flange, and it is about 30% that cutting force reduces, and the cutting friction also decreases, hole wall Glabrous thorn, and roughness can reach Ra6.3.

Description of drawings

Fig. 1 is the structural representation of the utility model cutting edge.

Fig. 2 is the top view of Fig. 1;

Fig. 3 is the B-B cutaway view of Fig. 1;

Fig. 4 is the C-C cutaway view of Fig. 1;

Fig. 5 is the A-A cutaway view of 2 Fig. 1;

The utility model is described further by preferred embodiment below in conjunction with accompanying drawing.

The specific embodiment

Shown in Fig. 1～5, a kind of drill bit that reduces the borehole wall roughness, that the cutting edge of common standard drill bit is worn into symmetrical step shape, form the first cutting edge CD section and the second cutting edge AB section, the distance H=8mm on described the first cutting edge and two-edged pinnacle parallel with the second cutting edge; Drift angle 2 Φ of common standard drill bit=120 ° are worn into 125 °; The long b ≈ of unit-type drill head chisel edge 8mm is worn into 2.3～2.6mm; With the α of the second cutting edge AB section relief angle by unit-type drill head ₁10 ° of ≈ wear into α ₁25 ° of ≈; The first cutting edge CD section and R arc place relief angle are worn into α ₂15 ° of ≈; First and second cutting edge pinnacle distance H=8mm, anterior angle γ sharpening is about 5 ° everywhere, AB ≈ 7～9mm, CD ≈ 7mm, ψ=60 °, R ≈ 7mm, each sharp corner must be carried on the back into fillet with oilstone, wants symmetrical about two R arcs.

Using method of the present utility model

It is identical with unit-type drill head that the utility model is installed, and cooling-lubricant is also identical, and the described bit diameter scope of application is Φ 40～Φ 60mm, and cutting speed V=30～40m/ divides, and amount of feeding S=0.25～0.50mm/ turns, and the sharpening drill bit is once about three hours in continuous operation.

Claims

1. drill bit that can reduce the borehole wall roughness, it is characterized in that: described drill bit is that the cutting edge of common standard drill bit is worn into symmetrical step shape, form the first cutting edge CD section and the second cutting edge AB section, described the first cutting edge distance (H) parallel with the second cutting edge and the two-edged pinnacle is 8mm; Relief angle (the α of described the second cutting edge AB section ₁) be 25 °, the relief angle (α of described the first cutting edge CD section ₂) and described the first cutting edge and the second cutting edge between the relief angle (α that locates of arc (R) ₂) be 15 °; The anterior angle (γ) of described the first cutting edge and the second cutting edge is 5 °; The chisel edge of described drill bit long (b) is 2.3～2.6mm.