CN210702729U

CN210702729U - Drill bit

Info

Publication number: CN210702729U
Application number: CN201921746853.4U
Authority: CN
Inventors: 于阳; 徐丽华
Original assignee: Jiangsu Wanzhong Precision Tools Co Ltd
Current assignee: Jiangsu Wanzhong Precision Tools Co Ltd
Priority date: 2019-10-17
Filing date: 2019-10-17
Publication date: 2020-06-09
Anticipated expiration: 2029-10-17

Abstract

The utility model relates to a drill bit, which comprises a handle part and a cutting part, wherein the cutting part comprises two cutting edges and two main chip grooves, the two cutting edges and the two main chip grooves are spirally and symmetrically distributed along the central axis of the drill bit, and the two cutting edges form a cross edge at the center of the front end surface of the cutting part; the drill bit is characterized in that the front ends of the main chip grooves are provided with chip grooves, when a user looks at the front end face of the drill bit, the radial depth of each chip groove accounts for 54-56% of the diameter of the edge of the drill bit, the chip grooves in the two main chip grooves are respectively positioned on two sides of the chisel edge, the width of the chisel edge is limited by the distance between the two chip grooves, and the width of the chisel edge accounts for 3-3.5% of the diameter of the chisel edge. When the drill is used for drilling nonferrous metals, the hole diameter with the tolerance grade of H7 and the roughness meeting Ra1.6 can be machined by one-time drilling.

Description

Drill bit

Technical Field

The utility model relates to a drill bit.

Background

When the prior art drills aiming at nonferrous metals, in order to ensure that the drilled hole diameter meets the tolerance of H7 and the roughness meets the requirement of Ra1.6, a drill bit and a reamer are used for processing twice, namely, the drill bit and the reamer are used for processing twice, and the traditional drill bit mainly has the following aspects for the reason that the drilled hole diameter can not be drilled out by one-time drilling:

1. the chisel edge of the drill bit is thick and unstable in centering, the drilling axis of the drill bit is easy to deviate during drilling, and important factors influencing the tolerance grade and the smoothness of the aperture not reaching the standard in the drilling process can be caused;

2. the drilled iron chips are large, the iron chips are not easy to discharge and easy to block a chip groove, and the iron chips are also important factors causing the tolerance grade and the smoothness of the aperture not to reach the standard;

3. the traditional drill bit only has two main cutting edges, and the main cutting edges generally only can play a drilling function and cannot play a function of finishing the aperture, which is an important factor causing the tolerance grade and the smoothness of the aperture not to reach the standard.

SUMMERY OF THE UTILITY MODEL

The to-be-solved technical problem of the utility model is: the defects of the prior art are overcome, and the problem that the drilled hole diameter cannot meet the requirements of tolerance and roughness Ra1.6 of H7 due to unstable chisel edge centering and unsmooth chip removal of the conventional drill is solved.

The utility model provides a technical scheme that its technical problem adopted is: a drill bit comprises a shank part and an edge part, wherein the edge part comprises two cutting edges and two main chip grooves, the two cutting edges and the two main chip grooves are spirally and symmetrically distributed along the central axis of the drill bit, and the two cutting edges form a chisel edge at the center of the front end surface of the edge part;

the front ends of the main chip grooves are provided with chip grooves, when a user looks at the front end face of the drill, the radial depth of each chip groove accounts for 54-56% of the diameter of the edge of the drill, the chip grooves in the two main chip grooves are respectively positioned on two sides of the chisel edge, the width of the chisel edge is limited by the distance between the two chip grooves, and the width of the chisel edge accounts for 3-3.5% of the diameter of the edge;

the chip pocket includes main rake face, curved chip winding surface and chip discharging surface, main rake face meets with the back knife face and forms main cutting edge, the radius of curvature R of chip winding surface is 7 ~ 8%, form chip angle gamma between main rake face and the chip discharging surface, chip angle gamma is 90 ~ 95.

Furthermore, the back surfaces of the two cutting edges are provided with auxiliary chip grooves, the two circumferential sides of the back surfaces of the cutting edges are respectively provided with a cutting edge zone and a smoothing edge zone, the cutting edge zone is positioned on one side of the rotation direction of the drill bit, and the auxiliary chip grooves are positioned between the cutting edge zone and the smoothing edge zone;

the rear cutter face comprises a first rear cutter face and a second rear cutter face, the first rear cutter face is connected with the main front cutter face to form the main cutting edge, an angle formed by a first wedge angle α between the first rear cutter face and the main front cutter face is 75-77 degrees, an edge of the back face of the cutting edge zone facing to one side of the rotating direction forms an auxiliary cutting edge, and the auxiliary cutting edge is connected with the back face of the cutting edge zone and the main chip removal groove;

the inner wall face of the auxiliary chip groove, which is located on one side of the smoothing blade zone, forms a smoothing rake face, the angle between the smoothing rake face and a second rear rake face, which is located at the front end of the smoothing blade zone, of a second wedge angle β is 85-88 degrees, the edge, which is located on one side of the rotation direction, of the front end of the smoothing blade zone forms a main smoothing edge, the main smoothing edge is connected with the second rear rake face and the smoothing rake face, the edge, which faces the rotation direction side, of the back edge face of the smoothing blade zone forms an auxiliary smoothing edge, and the auxiliary smoothing edge is connected with the back edge of the smoothing blade zone and the auxiliary chip groove.

Further, the depth of the chip flutes is 55% of the diameter of the drill blade.

Further, the curvature radius R of the chip surface is 7% of the blade diameter.

Further, a chip angle γ between the rake face and the chip surface is 90 °.

Further, the width of the chisel edge accounts for 3% of the blade diameter.

Furthermore, the blade part has a taper in the axial direction of the center of the drill bit, and the taper is 0.08-0.1/100.

Furthermore, the helix angle of the two cutting edges is 7-10 degrees.

Furthermore, a passivation surface is formed on the main cutting edge and is arranged along the length direction of the main cutting edge.

The utility model has the advantages that:

the utility model discloses a drill bit, when to the drilling of non ferrous metal, a drilling can process out the aperture that tolerance level satisfies Ra1.6 at H7 and roughness.

The utility model discloses a drill bit, through the radial degree of depth of controlling two chip pockets, the width that makes the chisel edge is controlled by the distance between two chip pockets, realizes thinning to the chisel edge, makes the drill bit obtain better centering ability before the drilling.

Secondly, the main cutting edge of drill bit is at the drilling in-process, and the iron fillings that drill out are discharged through the chip groove, promptly, in the iron fillings got into main chip groove after main rake face, arc chip winding surface and chip discharging surface in proper order, the chip winding surface can the iron fillings form the roll-over of small angle, lets the iron fillings can more easily discharge into main chip groove.

The drill bit of the utility model is additionally provided with the trimming edge zone on the cutting edge lobe, thereby forming a main trimming edge and an auxiliary trimming edge; rely on the main cutting edge of cutting land formation to realize the first drilling in aperture, then carry out the second time by vice smoothing sword in the aperture that the first drilling was accomplished and revise immediately, carry out the purpose of smoothing to the aperture promptly, through a drilling and a smoothing, thereby ensure the utility model discloses a drill bit can drill out the aperture and satisfy the aperture that H7's tolerance, roughness satisfied Ra1.6 required.

The utility model discloses a drill bit, the helix angle control of two cutting edges is at 7 ~ 10, intensity in the time of the helix angle greatly increased cutting of small angle, and the drilling is efficient.

Drawings

The present invention will be further explained with reference to the accompanying drawings.

FIG. 1 is a side view of the drill bit of the present invention;

FIG. 2 is a sectional view taken along line A-A of FIG. 1;

FIG. 3 is a schematic view of a front face of the drill bit;

FIG. 4 is a view taken along line K of FIG. 1;

FIG. 5 is a schematic view of a side elevational cutting margin;

FIG. 6 is a schematic view of a side elevational wiper land;

1. shank, 2, edge, 2A, cutting land, 2B, smoothing land, 3, primary flute, 31, flute, 311, primary rake face, 312, chip curl face, 313, chip discharge face, 4, secondary flute, 51, first flank face, 52, second flank face, 21, primary cutting edge, 22, secondary cutting edge, 23, primary smoothing edge, 24, secondary smoothing edge.

Detailed Description

The invention will now be further described with reference to the accompanying drawings. The drawings are simplified schematic diagrams only illustrating the basic structure of the present invention in a schematic manner, and thus show only the components related to the present invention.

As shown in fig. 1 to 6, a drill comprises a shank 1 and a blade 2, wherein the blade 2 comprises two lands and two main flutes 3, the two lands and the two main flutes 3 are spirally and symmetrically distributed along a central axis of the drill, and the two lands form a chisel edge at the center of a front end surface of the blade 2.

The front end of the main chip groove 3 is provided with a chip groove 31, and when a user looks at the front end face of the drill, the radial depth of the chip groove 31 accounts for 54-56%, preferably 55% of the diameter of the drill blade part 2. The depth of each of the two chip flutes 31 exceeds half of the blade diameter, so that the chip flutes 31 in the two main chip flutes 3 can be positioned on both sides of the chisel edge, and the width of the chisel edge is limited by the distance between the two chip flutes 31, so that the width of the chisel edge accounts for 3-3.5%, preferably 3%, of the blade diameter.

By controlling the radial depth of the two chip flutes 31, the width of the chisel edge is controlled by the distance between the two chip flutes 31, so that the chisel edge is thinned, and the drill obtains better centering capability before drilling.

Specifically, the chip pocket 31 includes a main rake face 311, an arc chip surface 312 and a chip surface 313, the main rake face 311 and the flank face are connected to form a main cutting edge 21, and the curvature radius R of the chip surface 312 is 7 to 8%, preferably 7%. A chip angle gamma is formed between the main front tool surface 311 and the chip surface 313, the chip angle gamma is 90-95 degrees, and the chip angle gamma is preferably 90 degrees. The curvature radius of the scrap rolling surface 312 enables the drilled scrap iron to form an angular bend, and the drilled scrap iron is prevented from being rolled into a large circle to block the main scrap discharge groove 3. The chip angle is adapted to discharge the iron chips rolled up by the chip surface 312 from the chip pocket 31 into the main chip discharge pocket 3.

Specifically, the back surfaces of the two cutting edges are provided with auxiliary chip grooves 4, the two circumferential sides of the back surfaces of the cutting edges are respectively provided with a cutting edge zone 2A and a smoothing edge zone 2B, the cutting edge zone 2A is located on one side of the rotation direction of the drill, and the auxiliary chip grooves 4 are located between the cutting edge zone 2A and the smoothing edge zone 2B.

The rear tool surfaces comprise a first rear tool surface 51 and a second rear tool surface 52, the first rear tool surface 51 is connected with the main front tool surface 311 to form the main cutting edge 21, an angle of a first wedge angle α formed between the first rear tool surface 51 and the main front tool surface 311 is 75-77 degrees, an edge of the back surface of the cutting edge strip 2A facing one side of the rotating direction forms an auxiliary cutting edge 22, and the auxiliary cutting edge 22 is connected with the back surface of the cutting edge strip 2A and the main chip removal groove 3;

the inner wall surface of the auxiliary chip groove 4 on one side of the smoothing margin 2B forms a smoothing rake surface, the angle of a second wedge angle β formed between the smoothing rake surface and a second rear rake surface 52 at the front end of the smoothing margin 2B is 85-88 degrees, the edge of the front end of the smoothing margin 2B on one side of the rotating direction forms a main smoothing edge 23, the main smoothing edge 23 is connected with the second rear rake surface 52 and the smoothing rake surface, the edge of the edge back surface of the smoothing margin 2B on one side of the rotating direction forms an auxiliary smoothing edge 24, and the auxiliary smoothing edge 24 is connected with the edge back surface of the smoothing margin 2B and the auxiliary chip groove 4.

The first wedge angle α on the land allows the primary cutting edge 21 to avoid contact of the first relief surface 51 with the workpiece while drilling, and the second wedge angle β on the land allows the primary wiper edge 23 to avoid contact of the second relief surface 52 with the workpiece while drilling.

The blade part 2 has a taper in the axial direction of the center of the drill bit, and the taper is 0.08-0.1/100.

The helix angle of the two blade lobes is 7-10 degrees; the small-angle lead angle greatly increases the cutting strength and the drilling efficiency.

A passivation surface (not shown in the figure) is formed on the main cutting edge 21, the passivation surface is arranged along the length direction of the main cutting edge 21, the passivation surface is connected with the main front cutter surface 311 and the first rear cutter surface 51, the passivation surface cannot be observed under naked eyes and can be observed only after being amplified by 50-80 times, and the passivation surface is obtained by machining in a CNC five-axis grinding machine mode; the main function of the blunt surface is to increase the chip strength of the main cutting edge 21.

When the drill bit of the utility model is used for drilling, the drill point on the chisel edge is firstly contacted with a workpiece, and the chisel edge becomes thin due to the width controlled by the chip grooves 31 at the two sides, so that the drill bit can well perform centering action during drilling; after the chisel edge drills into a workpiece, the main cutting edge 21 starts to work, the chip cutting strength of the main cutting edge 21 is improved by means of the passivated surface of the main cutting edge, the main cutting edge is not prone to opening collapse, drilled iron chips enter the chip rolling surface 312 after passing through the main front cutter surface 311, the curvature radius of the chip rolling surface 312 enables the iron chips to form small-angle bending, the formed iron chips are rolled into a small circle shape, and therefore the iron chips are easy to discharge; the chip angle gamma between the chip surface 313 and the rake surface discharges curled iron chips into the main chip discharge groove 3, and the chip angle gamma is preferably 90 degrees, so that the chips are more smoothly discharged. After the main cutting edge 21 drills, the secondary cutting edge 22 starts drilling the hole wall; subsequently, as the drill bit continues to rotate, the dressing margin 2B starts to work, the main dressing edge 23 starts to modify the aperture drilled by the main cutting edge 21, namely, secondary drilling, which is the key point for enabling the target aperture to reach (H7 grade and roughness ra 1.6), iron chips drilled by the main dressing edge 23 enter the auxiliary chip discharge groove 4 and then are discharged, and the auxiliary dressing edge 24 performs auxiliary dressing aperture, so that the aperture finally reaches the standard.

The utility model discloses a drill bit, at first realize the chisel edge of thinning through two chip pockets 31 that add, the chisel edge drill bit stability is guaranteed when drilling, this link is the first link that the target aperture was drilled in the drilling, the second link is that two chip pockets 31 make iron fillings export smoothly after forming little turn-up, prevent iron fillings jam in the hole and "galling" hole; the third link is that the cutting margin 2A and the trimming margin 2B work together, and the main trimming edge 23 of the trimming margin 2B trims the inner hole, which is equivalent to secondary trimming processing of the drill hole, thereby ensuring that the target aperture can be drilled finally.

In light of the foregoing, it will be apparent to those skilled in the art from this disclosure that various changes and modifications can be made without departing from the spirit and scope of the invention. The technical scope of the present invention is not limited to the content of the specification, and must be determined according to the scope of the claims.

Claims

1. A drill bit comprises a handle part and an edge part, wherein the edge part comprises two cutting edges and two main chip grooves which are spirally and symmetrically distributed along the central axis of the drill bit, and the two cutting edges form a chisel edge at the center of the front end surface of the edge part,

2. The drill bit as claimed in claim 1, wherein the land faces of the two lands are provided with auxiliary flutes, the two circumferential sides of the land faces of the lands are respectively provided with a cutting land and a smoothing land, the cutting land is positioned on one side of the drill bit in the rotation direction, and the auxiliary flutes are positioned between the cutting land and the smoothing land;

3. The drill bit of claim 1 wherein the flutes have a depth of 55% of the bit diameter.

4. The drill bit of claim 1, wherein the radius of curvature R of the chip forming surface is 7 to 8% of the diameter of the cutting edge.

5. The drill bit of claim 1, wherein a chip angle γ between the rake face and the chip face is 90 °.

6. The drill bit of claim 1, wherein the width of the chisel edge is 3% of the diameter of the blade.

7. The drill bit according to claim 1, wherein the blade portion has a taper in the axial direction of the center of the drill bit, the taper being 0.08 to 0.1/100.

8. The drill bit of claim 1, wherein the helix angle of the two lands is 7 to 10 °.

9. The drill bit of claim 2 wherein the major cutting edge has a blunt surface formed thereon, the blunt surface being disposed along the length of the major cutting edge.