CN101062525A - Full-helicoidal surface drilling tip head - Google Patents

Abstract

The invention relates to an overall thread sharp drilling head with the rear knife being a spiral surface, the axial line forming an included angle of 10degree-45degree with the drilling head shaft line. The drilling head not only meets three design parameters like drilling head half angle, oblique angle and circumference rear angle, it also meets the geometrical parameter, by selecting a fixed point b, point a sharing the same radius with b on the main cutting blade, tangential value of the b being the same with the z coordinate value of a and b and the ratio of a and b arc. If the distance between the center of a and b to the drilling head is r, rear knife tail gap of b should be: alpharh,h=tan-1(360h/2PIrOmega)=tan-1[360(Za-Zb/2PIr(Omegaa-Omegab)]t, with the sharp rear knife tail gap being 8degree-20degree. It can control the sharp angle distribution reasonably, with the bottom of the sharp knife blade and the bottom of the machined hole hard to interfere, applicable for making common drilling heads, mini ones and repairing for mini ones.

Description

A kind of full-helicoidal surface drilling tip head

Technical field

The present invention relates to a kind of drill bit, particularly relate to a kind of full-helicoidal surface drilling tip head, this full helical drill point both had been applicable to common drill bit, also was suitable for micro-bit.

Background technology

Drilling processing is one of most widely used machining process in the process industry.Up to now, it is still most economical in the hole processing, high-efficiency method.The cutter of using in the drilling process is a drill bit, and the difference according to knife face profile behind its apex point can be divided into apex point forms such as the conical surface, plane, ellipsoid, the face of cylinder; And the minor variations of apex point shape all will produce very large influence to its cutting ability.At present, the plane apex point not only is applied in the big drill bit, and commercial in the world micro drill all is to adopt the plane apex point, but this bit drills type has many deficiencies: the angular distribution that can not rationally control apex point; The bottom in knife face and processed hole easily interferes etc. behind the apex point.In order to overcome the deficiency of plane apex point drill bit, the present invention proposes a kind of common drill bit that both had been applicable to, also be suitable for the full-helicoidal surface drilling tip head of micro-bit.

Summary of the invention

Technical problem to be solved by this invention provides the distribution of knife face angle after a kind of angular distribution, particularly apex point that can rationally control apex point; The bottom in knife face and processed hole is difficult for interfering behind the apex point both is applicable to common drill bit, also is suitable for the full-helicoidal surface drilling tip head of micro-bit.

In order to solve the problems of the technologies described above, full-helicoidal surface drilling tip head provided by the invention comprises drill body and apex point thereof, and the back knife face of described apex point is a helicoid, the axis of this helicoid and the axes intersect of drill body at angle, this angle is 10 °～45 °.

Described drill bit is apex point half-angle, chisel edge angle and the outer rim turning point structure circumference relief angle except that satisfied three design parameters, also satisfy the tail clearance angle geometric parameter in knife face zone, back, this tail clearance angle geometric parameter, Chosen Point b on the knife face of back, then exist on the main cutting edge and 1 identical a of some b radius, the tangent value of the tail clearance angle that b is ordered equals the ratio of the Z coordinate difference of 2 of a, b and a, 2 arc length of b, suppose that " a ", " b " are r apart from bit central, then the back knife face tail clearance angle at " b " some place is:

${\mathrm{\&alpha;}}_{h,b}^r={\tan }^{-1}\left(\frac{360\mathrm{<figure-callout\; id="2"\; label="h"\; filenames="A20071003475700081.png,A20071003475700092.png"\; state="\{\{state\}\}">h</figure-callout>}}{2\mathrm{\&pi;r\&Omega;}}\right)={\tan }^{-1}\left[\frac{360(Z_a-Z_b)}{2\mathrm{\&pi;r}({\mathrm{\&Omega;}}_a-{\mathrm{\&Omega;}}_b)}\right]$

For the bottom that prevents drill bit back knife face and processed hole in drilling process interferes, can select big back knife face tail clearance angle for use; The apex point half-angle is directly connected to the size of main sword drift angle, have influence on the length of main cutting edge, the cutting load that the unit sword is long, the ratio of cutting width and thickness of cutting in the cutting lay, the ratio of axial force and tangential force in the cutting force, the size of main cutting edge anterior angle, cutting forms and the situation of chip removal and the radiating condition of outer rim turning point etc., therefore at concrete processing situation, the apex point geometric parameter of selecting for use is also different; The chisel edge angle is more little, and then the relief angle of each point increases on the cutting edge, and chisel edge length is long more, is in the negative rake cutting state, and resistance to cutting is big more, and the load of drill bit is big more, very easily causes drill bit to fracture; Structure circumference relief angle has influence on the size of drill bit structure relief angle, and drilling performance is had certain influence.

According to the difference of workpiece to be machined material, each geometric angle of the apex point of selecting for use is also different.Knife face tail clearance angle is got 8 °～20 ° behind the full helicoid drill bit apex point; The apex point half-angle is got 50 °～75 °; The chisel edge angle that is used for common drill bit is generally got 40 °～65 °, and is used for micro drill, carries out the preceding chisel edge angle of thinning and generally gets 65 °～85 °; Structure circumference relief angle is generally got 8 °～20 °.

Tail crack part at the helicoid of described apex point is formed with a plane, i.e. the second back knife face F ₃And F ₄

Adopt the full-helicoidal surface drilling tip head of technique scheme, because its apex point is full helicoid, promptly whole back knife face is continuous helicoid, and the axes intersect of its axis and drill bit self at angle; Its drill bit relief angle distributes rationally, excellent cutting performance; Its grinding method is simple, and the sharpening error source is few; This full helical drill point both had been applicable to common drill bit, also was suitable for micro-bit; And full helical drill point micro-bit is easy to carry out thinning at its apex point place.After introducing the tail clearance angle of back knife face, the geometric properties of main cutting edge and whole back knife face just can be described exactly, thereafter tail clearance angle on the knife face and the relief angle on the main cutting edge have obtained rational control, the value of control back knife face tail clearance angle just can prevent to interfere at the bottom of knife face and the hole behind the drill bit in the drilling process.Chisel edge is serpentine, and the centering ability is strong; The anterior angle of chisel edge strengthens, axially drag is little, incision steadily, thereby it is good to go into to bore performance, overcome the deficiency of plane apex point drill bit, better both be applicable to common drill bit for mechanical drilling manufacture field has proposed a kind of drilling performance, also be suitable for micro-bit, and be easy to its micro-bit is carried out the drill bit form of thinning.

In sum, the present invention is a kind of angular distribution that can rationally control apex point; The chisel edge distribution of shapes is reasonable; The bottom in knife face and processed hole is difficult for interfering behind the apex point, both has been applicable to common drill bit, also is suitable for micro-bit, and is easy to its micro-bit is carried out the full-helicoidal surface drilling tip head of thinning.

Description of drawings

The invention will be further described below in conjunction with drawings and Examples.

Fig. 1 is an apex point half-angle definition schematic diagram.

Fig. 2 is a chisel edge angle definition schematic diagram.

Fig. 3 is structure circumference relief angle α _FaThe definition schematic diagram.

Fig. 4 is back knife face tail clearance angle α _{H, b} ^rThe definition schematic diagram.

Fig. 5 is a knife face sharpening graph of a relation behind the full helicoid micro-bit apex point.

Fig. 6 is the full helicoid bit drills tip surface schematic diagram behind the web thinning.

Among Fig. 1,1---the drill bit main cutting edge; 2---rake face; C---outer rim turning point; F ₁---a rear flank knife face; ρ---apex point half-angle.

Among Fig. 2, F ₁And F ₂---the back knife face, figure (b) is A district partial enlarged view, wherein ψ---chisel edge angle among the figure (a).

Among Fig. 3, (b) figure is the B-B cutaway view among (a) figure, α _Fa---structure circumference relief angle: in through arbitrfary point " a " on the main cutting edge and plane perpendicular to the drill bit radius, the acute angle that the section became of knife face behind the vertical plane of drill axis and this some place.

Among Fig. 4, (b) figure is the A-A cutaway view among (a) figure, α _{H, b} ^r---back knife face tail clearance angle: Chosen Point b on the knife face of back, then exist on the main cutting edge and put 1 identical a of b radius, the tangent value of the tail clearance angle that b is ordered equals the ratio of the Z coordinate difference of 2 of a, b and a, 2 arc length of b.

Among Fig. 5,1---drill bit; 2---emery wheel; 3---the helicoid axis; The angle of Φ---drill axis and helicoid axes intersect; X ^*Y ^*Z ^*---knife face coordinate system behind the helicoid; XYZ---drill bit coordinate system; The pitch of H---helicoid.

Among Fig. 6, F ₁And F ₂---major first flank, F ₃And F ₄---the second back knife face.

The specific embodiment

Referring to Fig. 5, the back knife face of full helicoid drill bit apex point is made up of continuous helicoid, the back knife face of apex point is a helicoid, the axis of this helicoid and the axes intersect of drill body be Φ at angle, this angle Φ is 10 °～45 °, and the sharpening geometrical relationship is adjusted after emery wheel and the drill bit relative position according to back knife face grinding parameter as shown in Figure 5, emery wheel is fixed, and drill bit is around Z ^*In the time of the axle rotation, along Z ^*The axle moving linearly forms knife face behind the full helicoid drill bit apex point that pitch is H; Perhaps drill bit is fixed, and emery wheel is around Z ^*In the time of the axle rotation, along Z ^*The axle moving linearly forms knife face behind the full helicoid drill bit apex point that pitch is H.

At present in the design standard of relevant apex point, the handbook, the apex point geometric parameter generally is three: i.e. apex point half-angle ρ (see figure 1), chisel edge angle ψ (see figure 2) and outer rim turning point structure circumference relief angle α _Fc(see figure 3), their computational methods are as follows:

1, apex point half-angle ρ

In the X-Z plane, outer rim turning point C place is by rake face F ₅With back knife face F ₁The tangent slope of the main cutting edge that intersects and form is designated as ξ, then:

$\mathrm{\&xi;}={\left[\frac{\&PartialD;z}{\&PartialD;x}\right]}_C={\left[\frac{\frac{{\&PartialD;F}_1}{\&PartialD;x}\frac{{\&PartialD;F}_5}{\&PartialD;y}-\frac{{\&PartialD;F}_1}{\&PartialD;y}\frac{{\&PartialD;F}_5}{\&PartialD;x}}{\frac{{\&PartialD;F}_5}{\&PartialD;z}\frac{{\&PartialD;F}_1}{\&PartialD;y}-\frac{{\&PartialD;F}_5}{\&PartialD;y}\frac{{\&PartialD;F}_1}{\&PartialD;z}}\right]}_c---\left(1\right)$

Subscript in the formula " C " expression is to calculate at outer rim turning point place, Expression is to helicla flute equation F ₅Ask partial derivative to x, y, z.Then the apex point half-angle is:

$\mathrm{\&rho;}={\tan }^{-1}[-\frac{1}{\mathrm{\&xi;}}]---\left(2\right)$

2, chisel edge angle ψ

Represent back knife face equation F respectively ₁, F ₂Ask partial derivative to x, y, z.Chisel edge angle ψ is in the plane perpendicular to the drill bit axial line, and chisel edge is at the tangent line and the folded acute angle of X-axis of apex point center.It is worth available following formula and calculates:

$\mathrm{\&psi;}={{\tan }^{-1}\left[\frac{\&PartialD;y}{\&PartialD;x}\right]}_O={{\tan }^{-1}\left[\frac{\frac{{\&PartialD;\mathrm{<figure-callout\; id="1"\; label="F"\; filenames="A20071003475700081.png"\; state="\{\{state\}\}">F</figure-callout>}}_1}{\&PartialD;z}\frac{{\&PartialD;\mathrm{<figure-callout\; id="2"\; label="F"\; filenames="A20071003475700081.png,A20071003475700092.png"\; state="\{\{state\}\}">F</figure-callout>}}_2}{\&PartialD;x}-\frac{{\&PartialD;F}_1}{\&PartialD;x}\frac{{\&PartialD;F}_2}{\&PartialD;z}}{\frac{{\&PartialD;F}_1}{\&PartialD;y}\frac{{\&PartialD;F}_2}{\&PartialD;z}-\frac{{\&PartialD;F}_1}{\&PartialD;z}\frac{{\&PartialD;F}_2}{\&PartialD;y}}\right]}_O---\left(3\right)$

3, structure circumference relief angle α _Fc

Because measurement plane B-B is perpendicular to the drill bit radius, so the relief angle on the main cutting edge should be at coordinate system X _ΩY _ΩZ _ΩFollowing tolerance.For the arbitrfary point on the main cutting edge " a ", we can obtain coordinate system X _ΩY _ΩZ _ΩAs follows with the conversion relational expression of drill bit structure coordinate system XYZ:

$\left[\begin{array}{c}x\\ y\\ z\end{array}\right]=\left[\begin{array}{ccc}{\cos \mathrm{\&Omega;}}_a& -\sin {\mathrm{\&Omega;}}_a& 0\\ {\sin \mathrm{\&Omega;}}_a& {\cos \mathrm{\&Omega;}}_a& 0\\ 0& 0& 1\end{array}\right]\left[\begin{array}{c}{x}_{\mathrm{\&Omega;}}\\ y_{\mathrm{\&Omega;}}\\ z_{\mathrm{\&Omega;}}\end{array}\right]---\left(4\right)$

With knife face equation F after formula (4) substitution ₁, it is as follows to obtain under the coordinate system XYZ behind the drill bit Mathematical Modeling of knife face:

F ₁(x _Ω，y _Ω，z _Ω)＝0 (5)

Then on the main cutting edge more arbitrarily " a " relief angle of locating can be expressed as:

${\mathrm{\&alpha;}}_{\mathrm{fa}}={\tan }^{-1}{\left[\frac{{\&PartialD;z}_{\mathrm{\&Omega;}}}{{\&PartialD;y}_{\mathrm{\&Omega;}}}\right]}_a={\tan }^{-1}{[-\frac{\frac{{\&PartialD;\mathrm{<figure-callout\; id="1"\; label="F"\; filenames="A20071003475700081.png"\; state="\{\{state\}\}">F</figure-callout>}}_1}{{\&PartialD;y}_{\mathrm{\&Omega;}}}}{\frac{{\&PartialD;\mathrm{<figure-callout\; id="1"\; label="F"\; filenames="A20071003475700081.png"\; state="\{\{state\}\}">F</figure-callout>}}_1}{{\&PartialD;z}_{\mathrm{\&Omega;}}}}]}_a---\left(6\right)$

But above three parameters only can determine near the geometric properties the main cutting edge, above-mentioned three geometric parameters of many drill bits are all identical, but the whole drilling performance of drill bit but has bigger difference, and this just illustrates that three design parameters of drill bit can not determine the geometric properties of whole back knife face.Therefore above-mentioned three apex point geometric parameters are not enough to the geometrical property of unique definite apex point, also need to select else a geometric parameter.By theory analysis, full helicoid drill bit apex point is selected the tail clearance angle α in knife face zone, back _{H, η} ^r(see figure 4) parameter as a supplement is suitable.Therefore, (be apex point half-angle ρ, chisel edge angle ψ, outer rim turning point structure circumference relief angle α according to four apex point geometric parameters _FcAnd back knife face tail clearance angle α _{H, η} ^r) design full helicoid drill bit.

Back knife face tail clearance angle is defined as follows (see figure 4): Chosen Point b on the knife face of back, and then exist on the main cutting edge and put 1 identical a of b radius, the tangent value of the tail clearance angle that b is ordered equals the ratio of the Z coordinate difference of 2 of a, b and a, 2 arc length of b.After introducing the tail clearance angle of back knife face, the geometric properties of main cutting edge and whole back knife face just can be described exactly.Simultaneously, the value of control back knife face tail clearance angle just can prevent to interfere at the bottom of knife face and the hole behind the drill bit in the drilling process.

Suppose that " a ", " b " are r apart from bit central, then the back knife face tail clearance angle at " b " some place is:

${\mathrm{\&alpha;}}_{h,b}^r={\tan }^{-1}\left(\frac{360\mathrm{<figure-callout\; id="2"\; label="h"\; filenames="A20071003475700081.png,A20071003475700092.png"\; state="\{\{state\}\}">h</figure-callout>}}{2\mathrm{\&pi;r\&Omega;}}\right)={\tan }^{-1}\left[\frac{360(Z_a-Z_b)}{2\mathrm{\&pi;r}({\mathrm{\&Omega;}}_a-{\mathrm{\&Omega;}}_b)}\right]---\left(7\right)$

For the bottom that prevents drill bit back knife face and processed hole in drilling process interferes, can select big back knife face tail clearance angle for use; The apex point half-angle is directly connected to the size of main sword drift angle, have influence on the length of main cutting edge, the cutting load that the unit sword is long, the ratio of cutting width and thickness of cutting in the cutting lay, the ratio of axial force and tangential force in the cutting force, the size of main cutting edge anterior angle, cutting forms and the situation of chip removal and the radiating condition of outer rim turning point etc., therefore at concrete processing situation, the apex point geometric parameter of selecting for use also need not; The chisel edge angle is more little, and then the relief angle of each point increases on the cutting edge, and chisel edge length is long more, is in the negative rake cutting state, and resistance to cutting is big more, and the load of drill bit is big more, very easily causes drill bit to fracture; Structure circumference relief angle has influence on the size of drill bit structure relief angle, and drilling performance is had certain influence.

Chisel edge has very big influence to the cutting ability of drill bit, and the chisel edge of full helical drill point is 180 ° at the sharp angle that bores core point place, is unfavorable for the brill of going into of drill bit, and drill bit produces slippage at surface of the work easily; Chisel edge has very big negative rake, thereby can produce strong extruding with workpiece in working angles, and the centering performance of chisel edge, cutting ability are all bad.Therefore, if full helical drill point is used for micro-bit,, need carry out reconditioning to chisel edge in order to overcome the above problems, reach reduce the chisel edge negative rake, the purpose of centering effect when improving apex point and going into to bore, thereby improve the cutting ability of drill bit.Therefore according to full helicoid drill bit apex point feature, we have studied a kind of simple, thinning method of being applicable to micro drill, and promptly according to after good emery wheel of thinning parameter adjustment and the bit location, drill bit or emery wheel are along Z ^*Direction of principal axis moves a distance, and it is unbearable that emery wheel is milled to, at plane of part formation, tail crack of the former back of apex point knife face, the i.e. second back knife face F ₃And F ₄, in this way behind the web thinning, on plane of part formation, tail crack of the former back of drill bit knife face, as shown in Figure 6.

Therefore, by web thinning, finally can obtain according to four apex point geometric parameters (ρ, ψ, α _FcAnd α _{H, η} ^r) design full helicoid drill bit.

According to the difference of workpiece to be machined material, each geometric angle of the apex point of selecting for use is also different.Knife face tail clearance angle is got 8 °～20 ° behind the full helicoid drill bit apex point; The apex point half-angle is got 50 °～75 °; The chisel edge angle that is used for common drill bit is generally got 40 °～65 °, and is used for micro drill, carries out the preceding chisel edge angle of thinning and generally gets 65 °～85 °; Structure circumference relief angle is generally got 8 °～20 °.

Claims (4)

1, a kind of full-helicoidal surface drilling tip head comprises drill body and apex point thereof, it is characterized in that: the back knife face of described apex point is a helicoid, the axis of this helicoid and the axes intersect of drill body at angle, this angle is 10 °～45 °.

2, full-helicoidal surface drilling tip head according to claim 1, it is characterized in that: it is the apex point half-angle that described drill bit removes satisfied three design parameters, outside chisel edge angle and the outer rim turning point structure circumference relief angle, also satisfy the tail clearance angle geometric parameter in knife face zone, back, the geometric parameter of this tail clearance angle is to determine like this: Chosen Point b on the knife face of back, then exist on the main cutting edge and 1 identical a of some b radius, the tangent value of the tail clearance angle that b is ordered equals a, Z coordinate difference and a that b is 2, the ratio of 2 arc length of b, suppose " a ", " b " is r apart from bit central, and then the back knife face tail clearance angle at " b " some place is:

${\mathrm{\&alpha;}}_{h,b}^r={\tan }^{-1}\left(\frac{360h}{2\mathrm{\&pi;r\&Omega;}}\right)={\tan }^{-1}\left[\frac{360(Z_a-Z_b)}{2\mathrm{\&pi;r}({\mathrm{\&Omega;}}_a-{\mathrm{\&Omega;}}_b)}\right],$ Knife face tail clearance angle is got 8 °～20 ° behind this apex point.

3, full-helicoidal surface drilling tip head according to claim 2 is characterized in that: described apex point half-angle is got 50 °～75 °; The chisel edge angle that is used for common drill bit is got 40 °～65 °, and is used for micro drill, carries out the preceding chisel edge angle of thinning and gets 65 °～85 °; Structure circumference relief angle is got 8 °～20 °.

4, full-helicoidal surface drilling tip head according to claim 1 and 2 is characterized in that: when being used for the micro-bit apex point, by thinning, be formed with a plane in the tail crack part of the helicoid of described apex point, i.e. the second back knife face F ₃And F ₄

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