Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
  • B23B—TURNING; BORING
  • B23B51/00—Tools for drilling machines
  • B23B51/0002—Drills with connected cutting heads, e.g. with non-exchangeable cutting heads; Drills with a single insert extending across the rotational axis and having at least two radially extending cutting edges in the working position
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
  • B23B—TURNING; BORING
  • B23B2226/00—Materials of tools or workpieces not comprising a metal
  • B23B2226/75—Stone, rock or concrete
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
  • B23B—TURNING; BORING
  • B23B2251/00—Details of tools for drilling machines
  • B23B2251/04—Angles, e.g. cutting angles
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
  • B23B—TURNING; BORING
  • B23B2251/00—Details of tools for drilling machines
  • B23B2251/18—Configuration of the drill point
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B28—WORKING CEMENT, CLAY, OR STONE
  • B28D—WORKING STONE OR STONE-LIKE MATERIALS
  • B28D1/00—Working stone or stone-like materials, e.g. brick, concrete or glass, not provided for elsewhere; Machines, devices, tools therefor
  • B28D1/14—Working stone or stone-like materials, e.g. brick, concrete or glass, not provided for elsewhere; Machines, devices, tools therefor by boring or drilling
  • B28D1/146—Tools therefor

Definitions

• the present application relates to a drill insert and a drill bit using the drill insert, which are particularly suitable for drilling a hard material.
• Drill bits for drilling hard materials typically have forward impact and rotary cutting capacities.
• Fig. 1 schematically illustrates a conventional drill bit for drilling a hard material, the drill bit comprising a cemented carbide insert 1 and a drill shank 2 holding the insert 1 .
• a front end of the insert 1 is provided with a blade 5, the blade 5 comprising a chisel edge 5a and a pair of cutting edges 5z.
• Each cutting edge 5z is located on a corresponding main surface of the insert 1 .
• the chisel edge 5a and the two cutting edges 5z are all straight, and thus the insert 1 may be referred to as a straight-edged drill insert.
• the chisel edge 5a is mainly used for forward impact, and the two cutting edges 5z are mainly used for rotary cutting.
• the insert 1 has an axial direction X, a transverse direction Y and a thickness direction Z.
• the insert 1 has a rotation axis O in the direction X.
• the motions of the insert 1 include an impact motion in the direction X and a rotational motion about the rotation axis O.
• the distributions of the included angles a and [3 at this point of the blade 5 are shown in Fig. 3.
• the included angle a gradually increases from the midpoint as moving away from the rotation axis O.
• the included angle a also gradually increases as moving away from the rotation axis O.
• the included angle [3 is 0 at the entire chisel edge 5a, and the included angle [3 is maintained at a constant value at each cutting edge 5z.
• the present application aims to provide a drill insert and a drill bit using the drill insert, which can improve the material cutting capacity.
• a drill insert for drilling a hard material, the drill insert having a rotation axis in a direction X, two main surfaces opposite to each other in a direction Z, two side surfaces opposite to each other in a direction Y, a front end face, and a rear end face; wherein the front end face is provided with a blade, which comprises at least an end face blade segment defined by a line of intersection of a pair of tool faces on the front end face; the drill insert is manufactured to be adapted to perform a drilling operation at a rated impact velocity in the direction X and a rated rotational velocity about the rotation axis, so that at each point on the blade, an impact velocity component resulting from the rated impact velocity and a tangential velocity component resulting from the rated rotational velocity are combined into a result- ant velocity at this point; and the blade is configured such that the distribution of the orientation of an angular bisector of the blade follows the distribution of the direction of the resultant velocity over the entire extent of the
• an included angle between the orientation of the angular bisector of the blade and the direction of the resultant velocity is not greater than 10°, preferably not greater than 5°.
• the orientation of the angular bisector of the blade varies continuously and smoothly from the midpoint of the blade to each of the end points of the blade.
• an included angle between the angular bisector of the blade and the direction X increases continuously and smoothly from the midpoint of the blade to each of the end points of the blade.
• the included angle between the angular bisector of the blade and the direction X increases, from the midpoint of the blade to each of the end points of the blade, in the same trend as an included angle between the direction of the resultant velocity and the direction X.
• the blade has one or more segments where the orientation of the angular bisector is substantially constant.
• end points of the end face blade segment are located on the two side surfaces, and the blade only comprises the end face blade segment, with a middle part of the end face blade segment forming a chisel edge, and the parts of the end face blade segment on two sides of the middle part forming cutting edges.
• the end points of the end face blade segment are located on the two main surfaces, and the blade further comprises main surface blade segments respectively joined to the end points of the end face blade segment, each of the main surface blade segments being defined by a line of intersection of the corresponding tool face and the main surface on the front side of the tool face in a rotation direction; and the end face blade segment forms the chisel edge, and the main surface blade segments form the cutting edges; or the middle part of the end face blade segment forms the chisel edge, and the parts of the end face blade segment on the two sides of the middle part and the main surface blade segments form the cutting edges.
• the difference in the cutting angle at various positions on the entire blade is less than 20°, preferably less than 15°.
• the cutting angle at the end point of the chisel edge is equal to that at a start point of the cutting edge joined thereto.
• a drill bit comprising a drill shank and a drill insert mounted on the drill shank, the drill insert being a drill insert described above, wherein a blade of the drill insert is preferably formed by means of machining, such as grinding, the drill insert after mounting to the drill shank, so as to form various features related to the blade.
• the distribution of the orientation of the angular bisector of a sharp corner on the blade of the drill insert coincides with the distribution of the direction of velocity, so that the force application direction at various positions on the sharp corner is substantially consistent with the direction of velocity, and thus the material cutting capacity of the insert is significantly improved as compared with the straight-edged drill insert.
• Fig. 1 is a partial schematic diagram of a drill bit in the prior art
• Fig. 2 is a schematic diagram of the orientation of an angular bisector of a blade and the direction of velocity of an insert of the drill bit in Fig. 1 ;
• Fig. 3 is a distribution diagram of the orientation of the angular bisector of the blade and the direction of velocity of the insert of the drill bit in Fig. 1 ;
• Figs. 4 and 5 are respectively a front view and a top view of a drill insert according to an embodiment of the present application;
• Figs. 6 and 7 are respectively a top view and a perspective view illustrating the direction of velocity of the drill insert shown in Figs. 4 and 5;
• Fig. 8 is a perspective view illustrating the orientation of an angular bisector of a blade of the drill insert shown in Figs. 4 and 5;
• Figs. 9 to 11 are distribution diagrams of the orientation of the angular bisector of the blade and the direction of velocity of the drill insert shown in Figs. 4 and 5;
• Figs. 12 and 13 are top views of a drill insert according to other embodiments of the present application.
• the present application generally relates to a drill bit and a drill insert, which are used for drilling a hard material, especially stone.
• Figs. 4 and 5 illustrate a drill bit according to an embodiment of the present application.
• the drill bit comprises an insert 1 .
• the insert 1 is made of cemented carbide, is substantially plate-shaped, and is fixedly mounted (e.g., welded) to a drill shank (not shown).
• the insert 1 has a height direction (an axial direction) X, a width direction (a transverse direction) Y and a thickness direction Z.
• the insert 1 has a rotation axis O in the direction X.
• the insert 1 is flat, and has two main surfaces 1 a parallel to each other and two side surfaces 1 b parallel to each other.
• the side surfaces 1 b may be arranged obliquely (not perpendicular) to the main surfaces 1 a as shown, or may be perpendicular to the main surfaces 1 a.
• a front end face of the insert 1 (the face that faces the drilled material during drilling) axially bulges forward in the middle in the width direction.
• the front end face of the insert 1 is provided with two rotationally symmetrical tool faces 4.
• Each tool face 4 is at least partially curved.
• the outer boundary of each tool face 4 in the width direction Y is located on the corresponding side surface 1 b, and a line of intersection of the two tool faces 4 defines a blade segment 5a, that is, the inner boundary of each tool face 4 in the width direction Y is the blade segment 5a.
• the blade segment 5a is a smooth continuous curve.
• two end points A of the blade segment 5a are respectively located on the corresponding main surfaces 1 a.
• a line of intersection of the front portion of the corresponding tool face 4 in a rotation direction and the corresponding main surface 1 a defines a blade segment 5b.
• Each blade segment 5b extends from the corresponding end point A of the blade segment 5a to the corresponding side surface 1 b.
• the blade segment 5a and the two blade segments 5b joined thereto in the width direction Y form a complete blade 5 (a main edge).
• the blade segment 5a may be referred to as an end face blade segment
• the blade segment 5b may be referred to as a main surface blade segment. Since the blade segment 5a is a smooth continuous curve, it is generally not clear which part of the blade segment 5a is a chisel edge, as in the prior art in Fig. 1 . It can be considered that the part of the blade segment 5a within a certain distance from the rotation axis O is a chisel edge, and the parts outside the distance are cutting edges.
• the included angle between the projection of each end point A of the blade segment 5a in a plane YZ and the corresponding main surface 1a is preferably less than 30 degrees, most preferably less than 20 degrees.
• the blade 5 has a substantially 180° rotationally symmetrical shape. Each point on the blade 5 is the axially frontmost point among all the points on the insert at the same distance in the width direction from the rotation axis O. The point of intersection of the blade segment 5a and the rotation axis O is the frontmost point of the entire insert 1 in the axial direction X.
• a line of intersection of the rear portion of each tool face 4 in the rotation direction and the corresponding main surface 1a defines a rear edge (a secondary edge) 6.
• the height of each point on each rear edge 6 in the axial direction is less than the height of the corresponding point on the blade 5 to which the rear edge faces in the thickness direction Z.
• a reference plane P is taken for any point B on the blade 5, wherein the rotation axis O is parallel to the reference plane P or is within the reference plane P, and a vertical line from the point B to the rotation axis O is perpendicular to the reference plane P.
• the cross-section of the reference plane P on the insert 1 is shown as a profile line.
• the distance from the point B to the rotation axis O in the width direction is W.
• a velocity component Vr (which may be referred to as a tangential velocity component) at the point B resulting from rotation (counterclockwise in Fig. 6) of the insert 1 during operation is on the line of intersection of the reference plane P and the plane YZ and perpendicular to the vertical line from the point B to the rotation axis O.
• the forward impact of the insert 1 in the axial direction X during operation generates a velocity component Vx (which may be referred to as an impact velocity component) in the direction X at the point B.
• the velocity component Vx is perpendicular to the velocity component Vr.
• the velocity component Vr and the velocity component Vx are combined into a velocity V at the point B, and the velocity V forms an included angle a with the direction X.
• the reference plane P may also be referred to as a plane defined by the velocity component Vx and the velocity component Vr.
• the angular bisector L of the blade 5 forms an included angle [3 with the direction X.
• the distribution of the included angle a between the velocity V of the blade 5 and the direction X is schematically shown in Fig. 9.
• the abscissa axis represents the distance W in the width direction of the points on the cutter blade 5 from the rotation axis O, expressed as a percentage of the distance W to the total width of the insert 1 ; and the coordinate axis represents the included angle a between the velocity V at each point on the blade 5 and the direction X.
• the included angle a gradually increases from the midpoint of the blade 5 outwards in the width direction. Since the blade segment 5a is a smooth continuous curve, the included angle a varies smoothly without any abrupt change over the extent of the blade segment 5a. In addition, due to the gentle transition between the blade segment 5a and each blade segment 5b, there is no sharp-corner transition between the chisel edge and the cut- ting edge as obviously shown in Fig. 1 , and thus there is also no abrupt change at the junction between the blade segment 5a and each blade segment 5b.
• the value of the included angle a increases substantially monotonically without abrupt changes as moving further away from the midpoint of the blade 5 in the width direction.
• the orientation of its angular bisector L is desired to be as consistent as possible with the direction of velocity. That is, it is desired to design the included angle [3 between the angular bisector L of the blade 5 and the direction X to be as close as possible to the included angle a and to be distributed in essentially the same trend as the included angle a.
• Fig. 10 The distribution of the included angle [3 between the angular bisector L of the blade 5 and the direction X, designed and manufactured according to this concept, is shown in Fig. 10.
• the abscissa axis represents the distance W in the width direction from the points on the blade 5 from the rotation axis O
• the coordinate axis represents the included angle [3 at each point on the blade 5.
• the value of the included angle [3 increases substantially monotonically without abrupt changes as moving further away from the midpoint of the blade 5 in the width direction. Moreover, the difference between the value of the included angle [3 and the value of the included angle a at each point on the blade 5 is not greater than 10°, preferably not greater than 5°.
• Fig. 11 illustrates a distribution diagram of the included angles a and [3 after composition of Figs. 9 and 10. It can be seen that there is slight difference between the included angle [3 and the included angle a at each position on the blade 5.
• the designer can design the orientation of the angular bisector L at each point on the blade 5 using various popularly used design software, so as to achieve the desired orientation of the angular bisector L at each part.
• the orientation of the angular bisector L of the blade 5 can be considered as a force application direction in which the blade 5 cuts into the material. If the force application direction at the sharp corner of the blade 5 is consistent with the direction of velocity, the highest material cutting capacity is achieved. The greater the difference between the force application direction at the sharp corner and the direction of velocity, the weaker the material cutting capacity.
• the distribution of the included angle [3 follows the distribution of the included angle a, so that such an insert can be considered to have a better material cutting capacity.
• the distribution of the included angle [3 following the distribution of the included angle a means that the distribution trend of the included angle [3 is positively correlated with the trend of distribution of the included angle a. That is, in the directions from the centre in the width direction to two sides in the width direction, as the included angle a gradually increases (in a step-free manner), the included angle [3 also gradually increases (in a step-free manner), and the value of difference between the included angle [3 and the included angle a at each position is less than the value described above.
• the cutting capacity of the insert of the present application at each position of the blade is optimised, thereby significantly improving the overall cutting capacity of the insert.
• the included angles a and [3 are substantially in smooth transition at each position on the blade, and there is no significant difference between the included angle [3 and the included angle a, so that the entire insert has no part having obviously weakened cutting capacity.
• the blade 5 only comprises a smooth continuous curved blade segment 5a defined between the two tool faces 4 in the form of curved faces, the two end points of the blade segment are on the corresponding side surfaces 1 b, and the blade segments 5b shown in Figs. 4 and 5 are not present in this figure.
• the part of the blade segment 5a within a certain distance from the rotation axis O is a chisel edge, and the parts outside the distance are cutting edges.
• the orientation of the angular bisector L at various positions on the blade 5 is set to be as consistent as possible with the direction of velocity.
• Other aspects of the embodiment shown in Fig. 12 are the same as or similar to those shown in Figs. 4 and 5, and achieve the same technical effects, which will not be repeated.
• the blade 5 comprises a blade segment 5a in the middle and two blade segments 5b respectively joined to the corresponding end points of the blade segment 5a.
• the blade segment 5a is defined between the two tool faces 4 in the form of curved faces, is a smooth continuous curve, and has two end points located on the corresponding main surface 1 a.
• the two end points of the blade segment 5a are located within a certain distance from the rotation axis O, so that the entire blade segment 5a forms the chisel edge.
• the line of intersection of the front portion of each tool face 4 in the rotational direction and the corresponding main surface 1 a defines a blade segment 5b.
• Each blade segment 5b extends from the corresponding end point A of the blade segment 5a to the corresponding side surface 1 b.
• the two blade segments 5b are cutting edges.
• the orientation of the angular bisector L at various positions on the blade 5 is set to be as consistent as possible with the direction of velocity.
• Other aspects of the embodiment shown in Fig. 13 are the same as or similar to those shown in Figs. 4 and 5, and achieve the same technical effects, which will not be repeated.
• the blade 5 of the insert 1 may be in other forms, for example, a combination of multiple curved segments, or a combination with a straight segment, so as to achieve different functions of the insert 1 .
• the sections preferably have a smooth transition with each other.
• the orientation of the angular bisector at each position on the entire blade 5 of the present application is set to be as consistent as possible with the direction of velocity.
• the orientation of the angular bisector at various positions can be obtained from a combination of angles of the tool faces 4 on the front and rear sides of the blade segment 5a in the rotation direction.
• the orientation of the angular bisector at various positions can be obtained from the angle of the tool face 4 at the blade segment 5b relative to the main surface 1 a.
• the blade of the present application preferably varies continuously and smoothly in the orientation of the angular bisector at various positions. However, in the present application, there is also a situation where the blade has one or more segments having the substantially constant orientation of angular bisector.
• the cutting angle may be measured in the reference plane P described above.
• the included angle, at this point, between the line of intersection of a surface (the tool face or the main surface) on the front side in its rotation direction and the reference plane P and the line of intersection of a surface (the tool face) on the rear side in its rotation direction and the reference plane P is defined as the cutting angle at this point.
• the cutting angles at all positions on the entire blade 5 are designed comprehensively such that the difference in cutting angle at various positions on the entire blade is less than a certain angle (e.g., 20°, preferably less than 15°), the difference in cutting angle between the end point of the chisel edge and the start point of the cutting edge joined thereto is less than, preferably equal to, a defined angle (e.g., 10°), and there is preferably a smooth transition between the cutting angle of the chisel edge and the cutting angle of the cutting edge without abrupt changes in distribution.
• a certain angle e.g. 20°, preferably less than 15°
• a defined angle e.g. 10°
• it can be designed such that there is a smooth transition between the end point of the chisel edge and the start point of the cutting edge joined thereto.
• the insert can be machined (e.g., ground), after being fixed (e.g., welded) to the drill shank, to form the blade and the tool faces. It is also possible to machine (e.g., grind) the insert to form the blade and the tool faces and then fix the insert to the drill shank.
• the distribution of the orientation of the angular bisector at various positions on the blade follows and is as consistent as possible as the distribution of the direction of the resultant velocity resulting from the rated rotational velocity and the impact velocity of the drill bit at various positions on the blade, so that the insert has better cutting capacity at various positions, and thus the entire insert achieves the optimal drilling capacity.
• the blade 5 has a cross-section in the form of a sharp corner in the examples as shown, in practical applications, it is impossible to form an absolute sharp corner, but to be in the form of a rounded corner.

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Drilling Tools (AREA)

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Citations (4)

• 2022
  • 2022-07-05 CN CN202210791065.7A patent/CN117381029A/zh active Pending
• 2023
  • 2023-06-21 WO PCT/EP2023/066763 patent/WO2024008448A1/en unknown

Patent Citations (4)

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