CN2030121U

CN2030121U - Four-cutting-edge twist drill

Info

Publication number: CN2030121U
Application number: CN 88205377
Authority: CN
Inventors: 王世清
Original assignee: XI AN PETROLEUM COLLEGE
Current assignee: XI AN PETROLEUM COLLEGE
Priority date: 1988-05-10
Filing date: 1988-05-10
Publication date: 1989-01-04

Abstract

The utility model relates to a twist drill used for machining, provided with two main cutting edges which are radially arranged and four edge-lines, wherein, the two edge-lines are guiding edge-lines. The core bit of the twist drill used for machining is provided with a concave cutting edge instead of a chisel edge, the concave cutting edge and the two main cutting edges intersect to form two eccentric side tips of a drill bit; one of the eccentric side tips of the drill bit is high, and the other is low; thereby, axial force is diminished at the drilling and cutting time. Besides, an angle between the auxiliary edge-lines of the twist drill used for machining and the guiding edge-lines is 100 DEG-120 DEG, wherein, the middle part of one of the main cutting edge is provided with a chip dividing groove along the surface of the cutter on which the main cutting edge is arranged to make sideways resultant force to point to the guiding edge-lines; thereby, the twist drill used for machining has the advantages of smooth working and good guidance quality.

Description

Four-cutting-edge twist drill

The utility model relates to a kind of spiral bit that is used for mechanical processing industry.It has two main cutting edges and four lands, and wherein two is secondary land, and two other is the guiding land.

All there is a chisel edge at the unbearable place of common spiral bit, and from the outer rim point to unbearable, its anterior angle is reduced to negative rake by positive rake angle, there are the variations of tens degree front and back.Particularly at unbearable place because the existence and the cutting speed thereof of chisel edge are almost nil, and the drilling axial force is big, cause that drilling efficiency is low, power consumption is big.People try hard to address this problem for a long time, as have adopted various forms of grinding methods, make the cutting ability of spiral bit obtain certain improvement, but unbearable place still has chisel edge, and the abominable drilling condition at unbearable place does not obtain radical change.Chinese patent CN85200875 discloses a kind of four land spiral bits, and it has four main cutting edges and four lands.Two brill cutting edges that main cutting edge is arranged radially wherein, two other main cutting edge is the reaming cutting edge.Bore durability that expands composite drill bit and the problem that improves cutting speed though this drill bit has solved to improve, chisel edge still exists, and as foregoing, the drilling condition at unbearable place still can not get improving.In addition, though this drill bit has four lands, the guidance quality during drilling there is no and is clearly better.

The purpose of this utility model provides a kind of machining condition that can improve the unbearable place of drill bit significantly, and can improve the drilling guidance quality, thereby can improve the spiral bit of drilling efficiency and drilling quality.

Solution of the present utility model is: the spiral bit that is provided has main cutting edge and four lands of two arranged radiallys, and wherein two lands are secondary land, and the two other land is the guiding land.Special character of the present utility model is that unbearable part does not have traditional chisel edge, but be provided with the cutting edge of indent, the cutting edge of this indent links to each other with two main cutting edges respectively and forms two boring side sharps that depart from unbearable axis, and one of them boring side sharp is higher than another boring side sharp.The apex point (being an aforementioned higher boring side sharp) that is to say this drill bit departs from unbearable axis, and the cutting speed of apex point is non-vanishing during drilling, but cuts out a cone, and gives drill bit with assist location, thereby has reduced axial force greatly.Another special character of the present utility model is that a chip dividing groove is offered along knife face thereafter in the middle part of a main cutting edge therein, and to make secondary land and the angle Ω that leads between the land be 100 °-120 °.Can make two resulting side forces that main cutting edge produced point to one of them guiding land all the time like this, this guiding land that bears resulting side force is close to machined surface during drilling, thereby guiding work good, drill bit is more steady, has guaranteed drilling accuracy and surface roughness.

Below in conjunction with accompanying drawing content of the present utility model is described in detail.

Fig. 1 is the front view of a concrete structure of the utility model.

Fig. 2 is the attached view of Fig. 1.

Fig. 3 is the front view of the another kind of structure of the utility model.

As shown in Figure 1 and Figure 2: this drill bit has 1,2, two guiding of two secondary lands land 3,4.The helical angle of land is 30 °, angle Ω=110 ° of secondary land 1,2 and guiding land 3,4.Between two main cutting edges 5,6, have an indent by arc section 7a and tangent " √ " shape cutting edge 7 that forms of oblique line section 7b, wherein the radius of arc section 7a is about 1/8th of a bit diameter.Cutting edge 7 and two main cutting edges 5,6 intersect two boring side sharps 8,9 of formation, and wherein boring side sharp 8 is higher than boring side sharp 9, and the eccentric throw of boring side sharp 8 is 1/7th to 1/9th of a bit diameter.Offered narrow, a middle wide fish maw shape chip dividing groove 10 in two at the middle part of main cutting edge 5 along knife face thereafter.The comparable common spiral bit of sharp angle 2 φ of this drill bit is big, generally between 140 °～160 °.Drilling when this drill bit is mainly used in drill bushing.

Another kind of structure of the present utility model as shown in Figure 3, the indent cutting edge 11 at unbearable place is by two arc sections, 12,13 crossing forming, and form the apex point 14 of an off-centre, and the eccentric throw of apex point 14 is about 1/12nd of diameter, and it highly all is lower than two boring side sharps.With the exception of this, all the other structures are identical with last example, the drilling when this drill bit is mainly used in no drill bushing.

According to the difference of rapidoprint, the outer rim section of two main cutting edges of this drill bit can be a broken line shape, also can be arc, changes the anterior angle of main cutting edge peripheral edge portion with this.

Compared with the prior art, the axial force when great advantage of the present utility model is drilling is littler, thereby can strengthen the depth of cut, improves drilling efficiency. Simultaneously, the guidance quality of drill bit is good, and Comparision is steady. In addition, see Fig. 1, Fig. 2 if offer a chip dividing groove 15(at the front end place of guiding land), can bear dumpling and cut task, this drill bit has just become the compound tool that bores dumpling.

Claims

1, a kind of four land spiral bits, main cutting edge 5 with two arranged radiallys, article 6 and four, land, wherein two lands are secondary land 1,2, the two other land is guiding land 3,4, it is characterized in that being provided with the cutting edge 7 of indent in unbearable part, 11, the cutting edge 7 of this indent, 11 respectively with two main cutting edges 5,6 link to each other forms two boring side sharps 8 that depart from unbearable axis, 9, one of them boring side sharp 8 is higher than another boring side sharp 9, be provided with a chip dividing groove 10, said secondary land 1 at the middle part of a said main cutting edge 8 along knife face thereafter, 2 with the guiding land 3,4 angle Ω is 100 °～120 °.

2, spiral bit according to claim 1, the cutting edge 7 that it is characterized in that said indent is by arc section 7a and tangent the forming of oblique line section 7b " √ " shape cutting edge.

3, spiral bit according to claim 1 is characterized in that said indent cutting edge 11 by two arc sections, 12,13 crossing forming, and forms the apex point 14 of an off-centre.

4,, it is characterized in that narrow for two, the middle wide fish maw shape of chip dividing groove 10 according to the described spiral bit of claim 1～3.