CN216992340U

CN216992340U - Flat drill

Info

Publication number: CN216992340U
Application number: CN202220142833.1U
Authority: CN
Inventors: 吴宏
Original assignee: Rugao Qianjun Tools Co ltd
Current assignee: Rugao Qianjun Tools Co ltd
Priority date: 2022-01-19
Filing date: 2022-01-19
Publication date: 2022-07-19
Anticipated expiration: 2032-01-19

Abstract

The utility model relates to a flat drill, which comprises a drill handle and a flat cutting head, wherein the flat cutting head comprises a center positioning drill positioned in the center of the top of the flat cutting head, two auxiliary cutting edges oppositely arranged on two side surfaces of the flat cutting head, and a chisel edge connected between the top end of the auxiliary cutting edge and the bottom end of the center positioning drill, the center positioning drill is provided with a positioning cutting edge, and the flat drill is characterized in that: the ratio of the diameters of the central positioning drill and the flat drill is smaller; the front angles of the positioning cutting edge, the chisel edge and the secondary cutting edge are all inclined surfaces which are inwards sunk relative to the flat surfaces of the flat cutting head or are all cambered surfaces which are inwards sunk relative to the flat surfaces of the flat cutting head. The advantages are that: the diameter ratio of the height of the center positioning drill to the flat drill is lower, and meanwhile, the relative sizes and the angles of the positioning cutting edge, the chisel edge and the auxiliary cutting edge are designed, so that the hole wall and the bottom cutting surface of the blind hole are smooth during drilling.

Description

Flat drill

Technical Field

The utility model relates to a drill bit, in particular to a flat drill.

Background

The woodworking flat drill is mainly used for processing deep holes, a cutting part of the flat drill is ground into a flat body, and a main cutting edge grinds a sharp angle and a rear angle to form a chisel edge; the secondary cutting edge grinds a relief angle and a secondary deflection angle and controls the diameter of the drill hole.

In order to facilitate the processing of the woodworking flat drill, the center of the woodworking flat drill is provided with a positioning drill point which is used for positioning during drilling, but the ratio of the drill point to the diameter of the flat drill is larger. In addition, the flat chisel edge is designed to have a small sharp angle near the secondary cutting edge, and a design perpendicular to the axis of the drill rod is adopted near the center drill.

When the flat drill with the structure is used for drilling the blind hole, a deeper pit is formed in the center of the bottom of the blind hole, and the depth of the blind hole is not determined well; meanwhile, the bottom of the blind hole is not smooth, and the burrs are more, so that the flat drill is only suitable for punching holes.

SUMMERY OF THE UTILITY MODEL

The utility model aims to provide a flat drill which is suitable for blind hole machining and high in cutting speed.

In order to solve the technical problems, the technical scheme of the utility model is as follows: the utility model provides a spade drill, includes drillstock and platykurtic cutting head, the platykurtic cutting head is including being located platykurtic cutting head top center and boring the central positioning of the coaxial setting of drillstock brill, sets up two vice cutting edges at platykurtic cutting head both sides face relatively to and connect the chisel edge between vice cutting edge top and central positioning brill bottom, set up the location cutting edge on the central positioning brill, its innovation point lies in:

the height of injecing the center positioning brill on the drillstock axis direction is H, and the junction of injecing two vice cutting edges and two chisel edges is outer sword nodical, and the distance between two outer sword nodical is L, H: l = 0.14-0.3; the front angles of the positioning cutting edge, the chisel edge and the secondary cutting edge are all inclined planes or cambered surfaces which are inwards sunk relative to the flat surfaces of the flat cutting head. The diameter ratio of the height of the central positioning drill to the flat drill is lower, and meanwhile, the relative sizes and the angles of the positioning cutting edge, the cross edge and the auxiliary cutting edge are designed, so that the hole wall and the bottom cutting surface of the blind hole are smooth during drilling.

Specifically, an included angle between the inclined surface and the flat surface of the flat cutting head is 14-16 degrees, and the included angle is preferably 15 degrees. When the arc surface is formed, a plane which passes through the positioning cutting edge, the chisel edge or the auxiliary cutting edge and is parallel to the flat surface of the flat spade drill is defined as a reference plane, a plane which passes through the positioning cutting edge, the chisel edge or the auxiliary cutting edge and is tangent to the arc surface is an arc surface reference plane, an included angle between the reference plane and the arc surface reference plane is 14-15 degrees, and the included angle is preferably 14.45 degrees. The inclined plane and the cambered surface form a proper large inclination angle under a corresponding included angle, so that better cutting can be realized, and the cutting speed is higher.

Considering the speed of cutting the blind hole and the smoothness of the bottom of the blind hole, the included angle between the chisel edge and the secondary cutting edge is an acute angle or an obtuse angle, and when the included angle is an acute angle, the included angle between the two chisel edges is 140-152 degrees. When the included angle between the chisel edge and the minor cutting edge is an obtuse angle, the included angle between the two chisel edges is 145-155 degrees.

In addition, a chip removal chamfer structure is arranged on the flat surface of the flat cutting head, so that the problem of unsmooth chip removal of drilling is solved.

Drawings

Fig. 1 is a schematic structural view of a spade drill according to embodiment 1 of the present invention.

Fig. 2 is a front view of a spade drill according to embodiment 1 of the present invention.

FIG. 3 is a partial cross-sectional view and an enlarged view of a spade drill according to embodiment 1 of the present invention.

FIG. 4 is a partial cross-sectional and enlarged view of spade drill embodiment 2 of the present invention.

Fig. 5 is a schematic structural view of a spade drill according to embodiment 3 of the present invention.

Fig. 6 is a front view of a spade drill embodiment 3 of the present invention.

FIG. 7 is a partial cross-sectional and enlarged view of a spade drill according to embodiment 3 of the present invention.

FIG. 8 is a partial cross-sectional and enlarged view of a spade drill according to embodiment 4 of the present invention.

Detailed Description

Example 1

In this embodiment, as shown in fig. 1, the spade drill includes a drill shank 1 and a flat cutting head 2, the flat cutting head includes a center positioning drill 2a located at the center of the top of the flat cutting head and coaxially disposed with the drill shank 1, two minor cutting edges 22 oppositely disposed at both side surfaces of the flat cutting head, and a chisel edge 23 connected between the top end of the minor cutting edge 22 and the bottom end of the center positioning drill 21, and the center positioning drill 21 is provided with a positioning cutting edge.

As shown in fig. 2, the height of the center positioning drill in the axial direction of the drill shank 1 is defined as H, the joints of the two secondary cutting edges and the two chisel edges are defined as outer edge intersection points, and the distance between the two outer edge intersection points is L, H: l =0.2~ 0.3. In this embodiment, H: the ratio of L is preferably 0.25 to 0.27.

The included angle between the chisel edge 23 and the adjacent minor cutting edge 22, which takes the corresponding outer edge intersection point as the vertex, is an acute angle, and at this time, the included angle a between the two chisel edges is 140 to 152 degrees, preferably 146.36 degrees.

As shown in fig. 3, the rake angles of the positioning cutting edge 21, chisel edge 23, and minor cutting edge 22 are all inclined surfaces recessed relative to the flat surface of the flat cutting head. The included angle between the inclined surface and the flat surface of the flat cutting head is 14-16 degrees, and the preferred included angle is 15 degrees.

Furthermore, the flat surface of the flat cutting head is provided with a chip evacuation chamfer structure 24.

Example 2

The structure of the present embodiment is the same as that of embodiment 1, except that: as shown in fig. 4, the rake angles of the positioning cutting edge 21, the chisel edge 23 and the minor cutting edge 22 are all cambered surfaces recessed relative to the flat surfaces of the flat cutting head.

The plane which is parallel to the flat surface of the flat drill and penetrates through the positioning cutting edge, the chisel edge or the auxiliary cutting edge is defined as a datum plane, the plane which penetrates through the positioning cutting edge, the chisel edge or the auxiliary cutting edge and is tangent to the cambered surface is a cambered surface reference plane, the included angle between the datum plane and the cambered surface reference plane is 14-15 degrees, and the included angle is 14.45 degrees. The cambered surface is a circular arc surface in this implementation.

Example 3

In this embodiment, as shown in fig. 5, the spade drill includes a drill shank 1 and a flat cutting head 2, the flat cutting head includes a center positioning drill 2a located at the center of the top of the flat cutting head and coaxially disposed with the drill shank 1, two minor cutting edges 22 oppositely disposed at both side surfaces of the flat cutting head, and a chisel edge 23 connected between the top end of the minor cutting edge 22 and the bottom end of the center positioning drill 21, and the center positioning drill 21 is provided with a positioning cutting edge.

As shown in fig. 6, the height of the center positioning drill in the axial direction of the drill shank 1 is defined as H, the joints of the two secondary cutting edges and the two chisel edges are defined as outer edge intersection points, and the distance between the two outer edge intersection points is L, H: l =0.14~ 0.2. In this example, H: the ratio of L is preferably 0.16.

The present embodiment is different from

embodiments

1 and 2 in that: an included angle between each chisel edge 23 and the adjacent minor cutting edge 22, which takes the corresponding outer edge intersection point as a vertex, is an obtuse angle, and an included angle B between the two chisel edges 23 is 145-155 degrees.

As shown in fig. 7, the rake angles of the positioning cutting edge 21, chisel edge 23, and minor cutting edge 22 are all inclined surfaces recessed relative to the flat surface of the flat cutting head.

As with the embodiments, the included angle between the inclined surface and the flat surface of the flat cutting head is 14-16 degrees. The flat surface of the flat cutting head 2 is also provided with a chip evacuation chamfer 24.

Example 4

The present embodiment has basically the same structure as that of embodiment 3, and includes a drill shank 1 and a flat cutting head 2, the flat cutting head 2 includes a center positioning drill 2a, secondary cutting edges 22, and chisel edges 23, and an included angle between each chisel edge 23 and the adjacent secondary cutting edge 22, which has the corresponding outer edge intersection point as a vertex, is also an obtuse angle.

The only differences are: as shown in fig. 8, the rake angles of the positioning cutting edge 21, the chisel edge 23, and the minor cutting edge 22 are all curved surfaces recessed relative to the flat surfaces of the flat cutting head.

In the embodiment, the cambered surface is preferably an arc surface, a plane which passes through the positioning cutting edge 21, the chisel edge 23 or the secondary cutting edge 22 and is parallel to the flat surface of the flat spade drill is defined as a reference plane, a plane which passes through the positioning cutting edge, the chisel edge or the secondary cutting edge and is tangent to the cambered surface is a cambered surface reference plane, and an included angle between the reference plane and the cambered surface reference plane is preferably 14-15 degrees.

Claims

1. A flat drill comprises a drill handle and a flat cutting head, wherein the flat cutting head comprises a center positioning drill which is positioned at the center of the top of the flat cutting head and is coaxially arranged with the drill handle, two secondary cutting edges which are oppositely arranged on two side surfaces of the flat cutting head, and a chisel edge which is connected between the top end of the secondary cutting edge and the bottom end of the center positioning drill, and a positioning cutting edge is arranged on the center positioning drill, and the flat drill is characterized in that:

the height of the centre positioning brill is H on the drill shank axis direction in the injecing, and the junction of injecing two vice cutting edges and two chisel edges is outer sword nodical, and the distance between two outer sword nodical is L, H: l = 0.14-0.3;

the front angles of the positioning cutting edge, the chisel edge and the secondary cutting edge are all inclined planes or cambered surfaces which are inwards sunk relative to the flat surfaces of the flat cutting head.

2. The spade drill of claim 1, wherein: the included angle between the inclined surface and the flat surface of the flat cutting head is 14-16 degrees.

3. The spade drill of claim 2, wherein: the included angle is 15 degrees.

4. The spade drill of claim 1, wherein: and a plane which passes through the positioning cutting edge, the chisel edge or the auxiliary cutting edge and is parallel to the flat surface of the flat spade drill is defined as a reference plane, a plane which passes through the positioning cutting edge, the chisel edge or the auxiliary cutting edge and is tangent to the cambered surface is a cambered surface reference plane, and an included angle between the reference plane and the cambered surface reference plane is 14-15 degrees.

5. The spade drill of claim 4, wherein: the included angle is 14.45 degrees.

6. The spade drill according to any one of claims 1 through 5, wherein: the included angle between the chisel edge and the secondary cutting edge is an acute angle.

7. The spade drill of claim 6, wherein: the included angle between the two chisel edges is 140-152 degrees.

8. The spade drill according to any one of claims 1 through 5, wherein: the included angle between the chisel edge and the secondary cutting edge is an obtuse angle.

9. The spade drill of claim 8, wherein: the included angle between the two chisel edges is 145-155 degrees.

10. The spade drill of claim 1, wherein: the flat surface of platykurtic cutting head still is provided with chip removal chamfer structure.