JP2006102899A - Drill head for cutting deep hole - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a drill head for cutting a deep hole capable of increasing rotating feeding while materially increasing the number of cutting blades on the outer peripheral side, reducing a burden of each of the cutting blades on the outer peripheral side and reducing abrasion and damage of a knife edge by providing the cutting blades having the same guide pad function in lieu of a guide pad conventionally provided on a head end surface outer peripheral part of the drill head. <P>SOLUTION: The cutting blades are provided at least on the central side and the outer peripheral side of a head end surface part of a head body 1, at least three outer peripheral side cutting blades 6, 8, 9 are provided on the outer peripheral side without providing a guide pad, and, in order to impart a guide pad function to at least two cutting blades 8, 9 of the three cutting blades 6, 8, 9 on the outer peripheral side, each of the cutting blades 8, 9 is mounted on the head body 1 so that a head end part in the rotating direction of the head body of this outside protruded type round surface 10 makes contact with a hole wall 11 of a cutting material by forming the outside surface 10 into a protruded type round surface. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a deep hole cutting drill head for cutting a deep hole in a metal work material.

  As a conventional drill head for deep hole cutting, for example, there is one described in Patent Document 1. This will be described with reference to FIG. 4. Reference numeral 20 denotes a head body, which includes a tool shank mounting hole 21 that opens to the rear end surface, and a chip intake port 23 that opens to a front end surface 22 that protrudes substantially conically. 22, a center cutting edge 24, an intermediate cutting edge 25, and an outer peripheral cutting edge 26 are attached, and guide pads 28, 29, and 30 are attached to a distal end surface outer periphery 27.

The chip removal amount Q in the case of performing deep hole cutting using such a drill head is obtained by the following equation.
Q = π · Ap (Dc−Ap) Fn · N [mm ³ / min] (1)
However, Dc: Tool diameter [mm]
Ap: Cutting width [mm]
Fn: Rotation feed [mm / rev]
N: Number of revolutions [rpm]
Q: Chip removal amount [mm ³ / min]
In the above equation (1), if π · Fn · N is a constant k,
Q = Ap (Dc−Ap) k [mm ³ / min] (2)

Then, the chip removal amounts Qc, Qi, Qo by the respective receiving widths Wc, Wi, Wo of the center cutting edge 24, the intermediate cutting edge 25 and the outer peripheral cutting edge 26 are obtained as follows.
That is, the chip removal amount Qc by the bearing width Wc of the center cutting edge 24 is calculated by the above equation (2).
Qc = Wc (2Wc−Wc) k = Wc ² · k
Further, the chip removal amount Qi based on the bearing width Wi of the intermediate cutting edge 25 is expressed by the above equation (2).
Qi = Wi (2 (Wc + Wi) −Wi) k = Wi (2Wc + Wi) k
Further, the chip removal amount Qo by the bearing width Wo of the outer peripheral cutting edge 26 is expressed by the above equation (2).
Qo = Wo (2 (Wc + Wi + Wo) -Wo) k
= Wo (2Wc + 2Wi + Wo) k

Here, if Wc, Wi, and Wo are each set to the same dimension W,
Qc = W ² · k
Qi = 3W ²・ k
Qo = 5W ²・ k
Therefore, when the carrying widths of the respective parts are the same, the amount of chip removal is the largest at the outer peripheral cutting edge 26, the second is the smallest, and the central cutting edge 24 is the smallest. The ratio between the amount Qo and the chip removal amount Qi of the intermediate cutting blade 25 and the chip removal amount Qc of the center cutting blade 24 is
Qo: Qi: Qc: = 5: 3: 1
Japanese Utility Model Publication No. 3-130314

  As described above, in the drill head in which the center side cutting edge, the intermediate side cutting edge, and the outer peripheral side cutting edge are attached to the front end surface portion of the head body, the amount of chip removal by the outer peripheral cutting edge is five times that of the center side cutting edge. Although it is about 1.7 times the side cutting edge, there is only one outer peripheral cutting edge, so the blade edge is more worn and damaged than the middle and central cutting edges and must be replaced frequently. There is a limit to increasing the rotational feed (mm / rev), and the cutting efficiency cannot be sufficiently increased.

  In view of the above-described problems, the present invention substantially replaces the guide pad provided on the outer peripheral portion of the tip end surface of the drill head with a cutting blade having the same guide pad function as that of the drill head. Drills for deep hole cutting that increase the number of blades, thereby reducing the burden on each outer peripheral cutting blade and reducing the wear and breakage of the cutting edge, while increasing the rotational feed and increasing the cutting efficiency The object is to provide a head.

  Means for solving the above problems will be described with reference numerals in the embodiments described later. The deep hole cutting drill head according to claim 1 is at least the center side and the outer peripheral side of the tip surface portion of the head body 1. Are provided with at least three cutting edges 6, 8, and 9 on the outer peripheral side without providing a guide pad, and at least two of the three outer peripheral cutting edges 6, 8, and 9 are provided. In order to give the two cutting blades 8 and 9 a guide pad function, each of the two cutting blades 8 and 9 has an outer surface 10 that faces the hole wall 11 of the work material formed as a convex rounded surface. It is characterized by being attached to the head main body 1 so that the tip end portion of the convex round surface 10 in the rotation direction of the head main body is in contact with the hole wall 11 of the work material.

  According to a second aspect of the present invention, in the deep hole cutting drill head according to the first aspect, one of the three outer peripheral cutting edges 6, 8, and 9 is a main cutting edge, and the main cutting edge 6 and the other It is characterized in that lip height differences Ha and Hb are provided between the two cutting edges 8 and 9, respectively.

  Claim 3 is the deep hole cutting drill head according to claim 1 or 2, wherein the outer convex rounded surface 10 of the cutting edges 8, 9 is smaller in curvature radius than the curvature radius of the hole wall 11 of the work material. It is characterized by a rounded surface.

  The effect of the invention by the above solution will be described with reference numerals of embodiments to be described later. According to the field drill head of the invention according to claim 1, at least the center side and the outer peripheral side of the tip surface portion of the head body 1 Are provided with at least three cutting blades 6, 8, 9 on the outer peripheral side without providing a guide pad, and of these three outer cutting blades 6, 8, 9. In order to provide at least two cutting edges 8 and 9 with a guide pad function, each of the cutting edges 8 and 9 has an outer surface 10 facing the hole wall 11 of the work material as a convex rounded surface. Since the front end of the surface 10 in the rotation direction of the head body is attached to the head body 1 so as to be in contact with the hole wall 11 of the work material, the outer peripheral side with the largest amount of chip removal compared to the conventional deep hole cutting drill head The number of cutting edges is smaller than that of conventional drill heads. Therefore, the burden on the outer peripheral cutting blades 6, 8, and 9 is reduced, and the wear and breakage of the cutting edge is reduced. On the other hand, it is possible to increase the rotational feed and increase the cutting efficiency. it can.

  According to the second aspect of the present invention, one of the three outer peripheral side cutting edges 6, 8, 9 is the main cutting edge 6, and the main cutting edge 6 and the other two cutting edges 8, 9 By providing the lip height difference Ha, Hb between the two, the cutting efficiency can be further increased.

  According to the invention which concerns on Claim 3, by making the outer side convex round surface 10 of the said cutting blades 8 and 9 into the round surface of a curvature radius smaller than the curvature radius of the hole wall 11 of a workpiece material, The contact state with respect to the hole wall 11 becomes good, and the guide pad function can be more effectively operated.

  A preferred embodiment of the present invention will be described below with reference to the drawings. First, (a) in FIG. 1 is a front view showing a deep hole cutting drill head according to the present invention, and (b) is a side view. In the drawings, reference numeral 1 denotes a head main body. The head main body 1 is provided with a tool shank mounting hole 2 that opens to the rear end face side, and chip intakes 31, 32, and 33 that open to the front end face portion 3. Is provided with one center-side cutting edge 4, three outer-periphery-side cutting edges 6, 8, 9 and two intermediate-side cutting edges 5, 7 between the center side and the outer peripheral side. Therefore, the head main body 1 is provided with dedicated guide pads such as guide pads 28, 29, and 30 provided on the head main body 20 of the conventional deep hole cutting drill head as shown in FIG. Not.

  The cutting blades 4 to 9 are each composed of a throwaway tip formed of a cemented carbide material. Among these cutting blades 4 to 9, the center side cutting edge 4, the intermediate side cutting edge 5, and the outer peripheral side cutting edge 6. The three cutting blades 4 to 6 are the inner walls of the chip intake 31 in a state in which the side surfaces thereof are bonded to each other so as to form one cutting blade in the radial direction from the rotational axis G of the head body 1. Is inserted into the cutting blade mounting groove 12 provided in the slidably and is detachably attached by a screw 15, and the three cutting blades 4 to 6 constitute a main cutting blade. The intermediate cutting edge 7 and the outer peripheral cutting edge 8 at a position rotated by 180 ° from the main cutting edge are in a state in which the side surfaces thereof are attached to each other, and the cutting edge mounting groove 13 on the inner wall of the chip intake 32. The outer peripheral cutting edge 9 is fitted in a cutting blade mounting groove 14 on the inner wall of the chip intake 33 and is detachably attached by the screw 15.

  Each of the cutting blades 4 to 9 is formed in a substantially parallelogram shape when viewed from the front, as shown in FIG. 1 (b) and FIG. 3 (b), and is a bolt penetrating from the front center to the rear center. Insertion holes 16 are formed, and the upper and lower end edges on the front side are gently inclined in parallel to form cutting edge portions 17 respectively, and the upper and lower end portions on the front side each form a rake face 18 and Upper and lower end surfaces extending downwardly inclined from each blade edge portion 17 to the rear surface side form flank surfaces 19 having a predetermined clearance angle. Accordingly, each of the cutting blades 4 to 9 can use the other cutting edge portion 17 by reversing from the illustrated position when the cutting edge portion 17 at the use position shown in FIG. Become.

  The cutting edges of the outer peripheral cutting edges 6, 8, 9 are each provided with the cutting edge portion 17 at the upper and lower end edges as described above, while the outer peripheral cutting edges 6, 8, 9 have a guide pad function. 2 and 3 (a), the outer surface 10 facing the hole wall 11 of the work material is formed into a convex rounded surface, and this outer convex rounded surface is used for mounting. The front end of the surface 10 in the rotation direction of the head main body is attached to the head main body 1 so that the hole wall 11 of the work material is in contact and the rear thereof is gradually separated from the hole wall 11. 2 and 3A, the direction of rotation of the head body 1 is indicated by an arrow P. The guide pad function is a function for supporting a tool, that is, a drill head during deep hole machining, a function for crushing a work surface after cutting a work material with a cutting blade, and a diameter of the drill head. These functions ensure proper deep hole cutting.

  As can be seen from FIG. 3 (a), the outer convex round surfaces 10 of the outer peripheral cutting edges 6, 8, and 9 are round surfaces having a curvature radius sufficiently smaller than the curvature radius of the hole wall 11 of the work material. The outer convex rounded surface 10 is attached to the head body 1 such that the tip of the head body in the rotational direction of the head body is in contact with the hole wall 11 of the work material and the rear thereof is gradually separated from the hole wall 11. Since the head main body rotational direction front ends of the outer convex rounded surfaces 10, 10, 10 of the cutting blades 6, 8, 9 are in point contact with the hole wall 11 of the work material, the head main body 1 has these three points. The outer convex round surfaces 10, 10, 10 of the outer peripheral side cutting edges 6, 8, 9 are brought into a three-point contact state with the hole wall 11 of the work material, whereby the guide pad function can be effectively applied. .

  The outer convex rounded surfaces 10 of the outer peripheral cutting edges 6, 8, 9 may be rounded surfaces having a radius of curvature similar to the radius of curvature of the hole wall 11 of the work material, as in this embodiment. If the radius of curvature is sufficiently smaller than the hole wall 11 of the work material, for example, if the radius of curvature of the hole wall 11 is 25 mm and the radius of curvature of the radius surface 10 is 12 mm, the hole of the work material The contact state of the round surface 10 with respect to the wall 11 becomes good, and the guide pad function can be more effectively operated.

  Moreover, in this embodiment, in order to have all three outer peripheral cutting edges 6, 8, 9 have a guide pad function, the outer surface of each of the cutting edges 6, 8, 9 is formed into a convex round surface, The outer convex rounded surface 10 is attached to the head body 1 so that the tip of the head body in the rotation direction of the head body is in contact with the hole wall 11 of the work material. The guide pad provided on the head body of the drill head for deep hole cutting is Of the three outer peripheral cutting edges 6, 8, and 9, the outer peripheral cutting edge 6 serving as the main cutting edge is a normal outer peripheral cutting edge having no guide pad function. Also good.

  Moreover, the center side cutting edge 4, the intermediate side cutting edge 5, and the outer peripheral side cutting edges 6, 8, and 9 can all use the same structure and the same size cutting edge, thereby reducing the manufacturing cost. be able to.

  FIG. 2 (b) shows the lip height difference, which is the difference in height between the cutting blades 4-8 that are circumferentially opposed. That is, among the three outer peripheral cutting edges 6, 8, 9, the height of the outer peripheral cutting edge 6, which is the main cutting edge, is the highest, and the outer peripheral cutting edge 8 facing this in the rotational direction of the head body 1 Next, the remaining one outer peripheral cutting edge 9 is the lowest, and the difference in lip height between the outer peripheral cutting edge 6 and the outer peripheral cutting edge 8 is indicated by Ha. The lip height difference from the blade 9 is indicated by Hb. Further, between the two intermediate side cutting edges 5 and 7, the intermediate side cutting edge 5 as the main cutting edge is higher than the other intermediate side cutting edges 7, and the lip height difference between the two is indicated by Hc. Between the three outer peripheral cutting edges 6, 8, 9, the outermost cutting edge 9 is the next higher than the outer peripheral cutting edge 6, which is the main cutting edge, and the lowest is the outer peripheral cutting edge 8. It is good.

In addition, when the number of cutting blades arranged in the circumferential direction is n, the one-turn feed [mm / rev] of the drill head is F, and the lip height difference is H,
It is necessary to make the lip height difference H <F / n.
In this case, if the number of cutting blades arranged in the circumferential direction is 3, and the one-turn feed of the drill head is 0.2 mm, the lip height difference H is set to 0.06 mm, for example.

  As described above, the cutting efficiency can be further improved by providing the required amounts of lip height differences Ha, Hb, Hc between the cutting edges facing each other in the circumferential direction in the cutting edges 4-8.

  The deep hole cutting drill head according to the embodiment described above has one center side cutting edge 4, three outer peripheral side cutting edges 6, 8, 9, and two intermediate side cutting edges on the distal end surface portion 3 of the head body 1. The blades 5 and 7 are provided, and the three outer peripheral cutting blades 6, 8 and 9 form the outer surface 10 of each cutting blade as a convex rounded surface, and the head main body rotation direction of the outer convex rounded surface 10 The front end portion is attached to the head body 1 so as to be in contact with the hole wall 11 of the work material, and these three outer peripheral side cutting blades 6, 8, and 9 are each provided with a guide pad function. Compared to the conventional deep hole cutting drill head shown, the number of outer peripheral cutting blades with the largest amount of chip removal is three times that of the conventional drill head, so that the burden on the outer peripheral cutting blades 6, 8, 9 is reduced. This reduces the wear and breakage of the cutting edge while increasing the rotational feed and cutting performance. It can be increased.

  Of the cutting edges 4 to 9 attached to the head body 1, the three cutting edges 4 to 6, which are the center side cutting edge 4, the intermediate side cutting edge 5, and the outer peripheral side cutting edge 6, are the rotational axis of the head body 1. A cutting edge 31 is attached to the side of the chip intake 31 in a state where the side surfaces are bonded to each other so as to form a single cutting edge in the radial direction from G, and the intermediate cutting edge 7 and the outer peripheral cutting edge are formed. The blade 8 is attached in the chip intake 32 at a position 180 ° reversed from the main cutting edge in a state where the side surfaces are attached to each other, so that the intermediate cutting edge is also a conventional depth shown in FIG. One more than the drill head for drilling holes, and the total number of cutting edges of the conventional drill head for deep hole drilling is three, whereas the total number of cutting edges of the drill head according to the present invention is six. The cutting efficiency can be significantly increased because the cutting efficiency is substantially doubled.

  Also, since the three outer peripheral cutting edges 6, 8, and 9 all have a guide pad function, the function of supporting the tool, the crushing function after cutting the work material, and the diameter of the drill head are constant. Therefore, the guide pad function including the function of maintaining the depth can be more effectively exhibited, and deep hole cutting can be performed more appropriately.

  In the above embodiment, when the center surface cutting edge 4, the three outer peripheral cutting edges 6, 8, 9 and the two intermediate cutting edges 5, 7 are provided on the tip surface portion 3 of the head body 1. However, three or more outer peripheral cutting edges can be provided according to the diameter of the head body 1. For example, four cutting blades having a guide pad function and one main cutting blade having no guide pad function are provided. Alternatively, it may be composed of one central side cutting edge and three outer peripheral side cutting edges. In this case, one central side cutting edge and one outer peripheral side cutting edge are formed from the rotational axis of the head body 1. It arrange | positions in the state which mutually attached the side surfaces so that the cutting blade of 1 sheet may be formed in radial direction.

(a) is the front view which shows the drill head for deep hole cutting which concerns on this invention, (b) is a side view. (a) is an enlarged view of (a) of FIG. 1, and (b) is an explanatory view for explaining a lip height difference between cutting edges. (a) is a partially enlarged view of (a) of FIG. 2, (b) is a drawing of the cutting edge shown in (a) as seen from the front side, and (c) is a sectional view taken along line XX of (a). is there. (a) is a front view of a conventional deep hole drilling head, and (b) is a side view.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Head main body 4 Center side cutting edge 5 Middle side cutting edge 6 Outer peripheral side cutting edge 7 Intermediate side cutting edge 8 Outer peripheral side cutting edge 9 Outer peripheral side cutting edge 10 Outer convex round face 11 Hole wall Ha of work material Lip height difference Hb Lip height difference Hc Lip height difference

Claims (3)

  A cutting blade is provided on at least the center side and the outer peripheral side of the tip surface portion of the head body, and at least three cutting blades are provided on the outer peripheral side without providing a guide pad. In order to provide at least two cutting blades with a guide pad function, each of the two cutting blades has a convex round surface formed on the outer surface facing the hole wall of the work material, and the head of the outer convex round surface is formed. A drilling head for deep hole cutting, characterized in that it is attached to the head main body so that the tip in the main body rotating direction is in contact with the hole wall of the work material.   2. One of the three outer peripheral cutting edges is a main cutting edge, and a lip height difference is provided between the main cutting edge and the other two cutting edges, respectively. The drill head for deep hole cutting described. 3. The deep hole cutting drill head according to claim 1, wherein the outer convex rounded surface of the cutting edge is a rounded surface having a radius of curvature smaller than the radius of curvature of the hole wall of the work material.

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