JP2007216321A - Boring head - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a boring head including a chip discharge port and a cutting blade at the front end, fitted to the tip of a hollow boring bar to drill a deep hole in work material, restraining abrasion of a side wall part of the chip discharge port, and having excellent durability. <P>SOLUTION: A chip discharge outlet 11 communicating with the chip discharge passage 10 is opened in the front end part of the substantially cylindrical head body 1, the interior of which serves as the chip discharge passage 10, cutting blades 21, 23, 25 are fitted to the side wall part 11a along the radial direction of the chip discharge outlet 11, and a wear resisting member 3 made of material having higher hardness than the base material of the head body 1 is put on at least the leading edge side of the side wall part 11b substantially along the radial direction adjacent to the side wall part 11a fitted with the cutting blades 21, 23, 25. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a boring head that is provided with a chip discharge port and a cutting blade at a front end, and is attached to the tip of a hollow boring bar to make a deep hole in a work material made of metal or the like.

  In general, the cutting efficiency of deep hole machining is more dependent on the ability to discharge chips generated inside the cutting hole during machining to the outside than the capability of the tool system. For this reason, in the deep hole cutting device, a hollow boring bar is used, and a chip discharge port that opens from the top surface to the peripheral surface is provided at the front end portion of the cylindrical boring head attached to the tip, and the chips are supplied to the cutting portion. The coolant is discharged from the discharge port to the outside through the inside of the boring bar. This coolant supply system includes a single tube system that supplies the cutting part through the gap between the single tubular boring bar and the cutting hole, and a double tube system that supplies the cutting part through the space between the inner and outer cylinders of the double tubular boring bar. There is. In addition, in a boring head applied to a large hole diameter, a plurality of cutting blades that share cutting radius are used, and the cutting blades are distributed and attached to the side walls of two large and small chip discharge ports arranged substantially opposite to each other in the radial direction. There is what I did.

  5A and 5B show a conventional double tube boring head H0 used for deep hole cutting with a large hole diameter. The head main body 1 of the boring head H0 has a substantially cylindrical shape that forms a chip discharge passage 10 whose inside is open to the base end side, and has an obtuse conical front end portion 1a having two large and small portions communicating with the discharge passage 10. The chip discharge ports 11 and 12 are opened in a substantially rectangular shape. And, on the side wall portion 12a along the head radial direction on the large chip discharge port 11 side, odd numbers, that is, the first, third and fifth cutting blades 21, 23, 25 are attached in order from the head center side. The same even number, that is, the second and fourth cutting blades 22 and 24 are attached to the side wall portion 12a on the side of the small chip discharge port 12 which is substantially in the same radial direction as the side wall portion 11a, and five locations on the front outer periphery 1b. Are attached with guide pads 4 made of super hard material.

  Each of the cutting blades 21 to 25 has a three-fold symmetry (the section shape when the section is divided into three at a central angle of 120 °) formed by three cutting blades 2 each having a chevron with long and short sides 2a and 2b. ) With a thick plate-shaped throw-away tip that is screwed to the square-axis tip holding piece 20 and can be used three times as a new blade (updated twice) by changing this fixed position by 120 ° Each chip holding piece 20 is fitted to a chip mounting seat 13 recessed on the chip body 1 side and mounted in a screw insertion hole 14 extending from the outer peripheral surface of the head body 1 to each chip mounting seat 13. The chip holding piece 20 is screwed by a screw 7. Thus, each cutting blade 2 of the cutting blades 21 to 25 has an arrangement posture in which the long side 2a which is the main portion thereof is inclined to the right side (inclined to the right side when viewed from the front = inclined to the head center side). This improves the straightness of drilling.

  The boring head H0 is attached by screwing a rear portion 1c provided with a male screw 15 on the outer periphery into an outer cylinder tip of a double tubular boring bar (not shown). In this attached state, the inner cylinder tip of the boring bar is attached. The coolant lead-out holes 17... That engage with the inner annular step portion 16 and are equally distributed in the circumferential direction of the intermediate portion face the inner and outer cylinders of the boring bar, and supply the coolant that is fed between the inner and outer cylinders. It leads to the outside and is supplied to the cutting part. The machining is performed by connecting the boring bar to a drive shaft such as a spindle of a machine tool and rotating it, or by rotating the work material side to cut the work material with the cutting blades 21 to 25 to make a deep hole. Form. The relative rotation direction of the boring head H0 during this processing is the counterclockwise direction in FIG.

  However, in the conventional boring head H0, the side wall portion 11b along the radial direction of the head adjacent to the side wall portion 11a on the cutting blade attachment side of the large chip discharge port 11 is severely worn due to machining. There was a problem that the part 11b could not be used at an early stage due to wear and deformation on the front edge side. Such a problem occurs in the same way even in a boring head having one cutting blade (one chip discharge port) or three (two chip discharge ports). .

  Therefore, the present inventors investigated the cause of the intense wear of the side wall portion in this type of conventional boring head. As a result, the cutting edge generated by the cutting blade main portion of the cutting blade has a right-handed inclination. 5, for example, in the boring head H0 having the configuration shown in FIG. 5, the first cutting blade 21 responsible for cutting at the center side of the cutting radius is positioned in the side wall portion as shown by the phantom line in the drawing. Since it is close to 11b, it has been found that the chip S generated from the cutting blade 21 hits the side wall 11b before it is divided, and the side wall 11b is always rubbed by the chip S and is severely worn.

  The present invention is a boring head that is equipped with a chip discharge port and a cutting blade at the front end and is attached to the tip of a hollow boring bar to drill a deep hole in a work material. By adding, it aims at suppressing the abrasion of the side wall part of a chip discharge port, and providing the thing provided with the outstanding durability.

  In order to achieve the above object, a boring head according to a first aspect of the present invention is shown at the front end portion of a substantially cylindrical head body 1 whose inside forms a chip discharge passage 10 if shown with reference numerals in the drawings. The chip discharge port 11 communicating with the chip discharge path 10 is opened, and the cutting blades 21, 23, 25 are attached to the side wall portion 11a along the radial direction of the chip discharge port 11, and the cutting blade in the chip discharge port 11 is provided. A wear-resistant member 3 made of a material harder than the base material of the head body 1 is attached to at least the front edge side of the side wall part 11b that is adjacent to the side wall part 11a to which the 21, 23, and 25 are attached. The structure is

  According to a second aspect of the present invention, in the boring head of the first aspect, the pair of chip discharge ports 11 and 12 disposed substantially opposite to each other in the radial direction and the side wall portions 11a and 12a of the both chip discharge ports 11 and 12 are attached to be distributed. And a plurality of cutting blades 21 to 25 that share the cutting radius, and the cutting blade main portion (long side 2a) of the cutting blade 21 that performs cutting in the most central region of the cutting radius has a right-handed inclination. The wear-resistant member 3 is attached to the chip discharge port 11 facing the most central cutting blade 21.

  According to a third aspect of the present invention, in the boring head of the first or second aspect, the plate-like wear-resistant member 3 is fixed to the side surface portion 5a of the support block 5, and the support block 5 is screwed to the head body 1 side. It is assumed that the block mounting seat 6 is recessed.

  According to a fourth aspect of the present invention, in the boring head of the third aspect, the head body 1 includes a pair of chip discharge ports 11 and 12 disposed substantially opposite to each other in the radial direction, and the support block 5 is provided at both the chip discharge ports 11 and 12. Each of the side surfaces 5a and 5b faces each other, and the wear-resistant member 3 is fixed to one side surface 5a, and the cutting blade mounting seat 13a is recessed in the other side surface 5b.

  According to a fifth aspect of the present invention, in the boring head according to any one of the first to fourth aspects, the cutting blades 21 to 25 are made of a throw-away tip.

  According to the first aspect of the present invention, at least the front edge side of the side wall portion along the substantially radial direction adjacent to the side wall portion to which the cutting blade is attached is covered with the wear resistant member made of a material harder than the base material of the head body. Therefore, the wear of the side wall portion due to scraping of chips is suppressed, and a boring head having excellent durability is provided.

  According to the invention of claim 2, a cutting blade as a boring head comprising a pair of chip discharge ports arranged substantially opposite to each other in the radial direction and a plurality of cutting blades attached to the side walls of both chip discharge ports. The main part is close to the most central cutting blade having a right-handed inclination, so that it is possible to suppress wear of a portion that is originally particularly prone to intense wear, and has excellent durability.

  According to the invention of claim 3, the plate-like wear-resistant member is fixed to the side surface portion of the support block, and the block mounting seat for screwing the support block is recessed on the head main body side. Since the wear-resistant member can be easily and reliably positioned with high positional accuracy, and the wear-resistant member itself can be set small by the support block, the amount of expensive high-hardness material used is reduced, leading to cost reduction.

  According to the invention of claim 4, in the configuration in which the boring head includes a pair of chip discharge ports and a plurality of cutting blades, the support block of the wear-resistant member has side portions respectively facing both chip discharge ports, Since the wear-resistant member is fixed to one side surface and the cutting blade mounting seat is recessed on the other side surface, the structure of the mounting portion of the wear-resistant member is avoided, and the wear resistance member is prevented. The wear member and the cutting blade can be functionally arranged.

  According to the invention of claim 5, the wear of the side wall portion of the chip discharge port due to scraping of the chip as a boring head composed of a throw-away tip capable of renewing the cutting blade once or twice by the rotational displacement of the mounting posture. Is suppressed, and a product with excellent durability is provided.

  Hereinafter, an embodiment in which the present invention is applied to a double-tube boring head used for deep hole cutting with a large hole diameter will be specifically described with reference to the drawings. 1 shows the entire boring head, FIG. 2 shows the head body, FIG. 3 shows the support block to which the wear-resistant member is fixed, and FIG. 4 shows the main part of the head body to which the support block is attached. Since the basic structure of the boring head H1 of this embodiment is the same as that of the conventional boring head H0 described with reference to FIG. 5, the same reference numerals are given to the common parts with the conventional boring head H0. The description is omitted.

  As shown in FIGS. 1A and 1B, in this boring head H1, a pair of substantially fan-shaped regions sandwiched between two large and small chip discharge ports 11 and 12 at the obtuse conical front end portion 1a of the head body 1. Among them, a substantially rectangular parallelepiped support block 5 having side portions 5a and 5b facing the chip discharge ports 11 and 12 on the head center side in the region where the even-numbered cutting blades 22 and 24 are fixed is screwed. It has been stopped. A plate-shaped wear-resistant member 3 made of a material harder than the base material of the head body 1 is fixedly integrated by welding or the like to the side surface portion 5a facing the large chip discharge port 11 of the support block 5. A cutting blade mounting seat 13a for the second cutting blade 22 is formed on the side surface portion 5b facing the small chip discharge port 12.

  As shown in FIGS. 3A to 3C, the support block 5 extends from the slightly inclined top surface portion 5 c constituting the obtuse conical front end portion 1 a of the head body 1 to the bottom surface portion 5 d. And a single screw insertion hole 52 having one end opened to the inner peripheral surface of the cutting blade mounting seat 13a in parallel with the side surface portion 5a, and the bottom surface portion 5d has a side surface portion 5a. A locking protrusion 53 is formed along the side edge on the opposite side. The screw insertion holes 51... 52 are designed to lock the heads of the mounting screws 4 and 7 (see FIG. 4) at the boundary step portions 51a and 52a with the inner end side as a small diameter portion. .

  As shown in FIGS. 2 (A) and 2 (B), a block mounting seat 6 extending between the chip discharge ports 11 and 12 is recessed at the mounting position of the support block 5 at the front end 1a of the head body 1. The bottom surface portion 6 a of the block mounting seat 6 has four screw holes 61 corresponding to the four screw insertion holes 51 of the support block 5 and corner edges corresponding to the locking protrusions 53 of the support block 5. The locking groove 62 is provided. Further, a screw insertion hole 14 a corresponding to the second cutting blade 22 of the head main body 1 opens in the inner wall surface of the block mounting seat 6.

  In the assembly of the boring head H1, as shown in FIG. 4, the locking protrusion 53 is engaged with the support block 5 having the wear-resistant member 3 fixed to the side surface portion 5a with respect to the block mounting seat 6 of the head body 1. The mounting screws 8 are fitted so as to be engaged with the stop grooves 62 and inserted into the four screw insertion holes 51... From the top surface side. Further, as shown in FIG. 1A, the cutting blades 21 to 25 made of throwaway chips are screwed to the cutting blade mounting seats 13 of the head body 1 and the cutting blade mounting seat 13a of the support block 5, respectively. Each of the chip holding pieces 20 is fitted, and the mounting screws 7 inserted from the outer peripheral side into the screw insertion holes 14 and 14a are screwed and tightened into the screw holes of the chip holding piece 20, whereby the cutting blades 21 to 25 of the head body 1 are fixed. Attach to the head body in the order of arrangement described above. The screw insertion hole 14a of the head main body 1 corresponding to the second cutting blade 22 is set so as to communicate concentrically with the screw insertion hole 52 of the attached support block 5.

  The boring head H1 having the above-described configuration is attached by screwing the rear portion 1c provided with the male screw 15 into the distal end portion of an outer cylinder of a double tubular boring bar (not shown) as in the conventional one described above. As a result, the tip of the inner cylinder of the boring bar engages with the annular step 16 inside the boring head H1, and coolant outlet holes 17 formed equally in the circumferential direction of the intermediate section are formed between the inner and outer cylinders of the boring bar. The coolant that is fed through the inner and outer cylinders of the boring bar during machining is led out from the coolant lead-out holes 17 to be supplied to the cutting part.

  In this boring head H1, since the long side 2a which forms the main part of the cutting blade 2 of the cutting blades 21 to 25 is right-handed, chips generated during machining are curled inwardly, particularly at the center side of the cutting radius. Chips generated from the first cutting blade 21 responsible for cutting hit the front end side of the side wall portion 11b that is close in position before being divided and flowing into the chip discharge port 11 together with the coolant. Accordingly, the side wall portion 11b is always scraped by the chips S during processing, but the surface of the side wall portion 11b is covered with the wear-resistant member 3 made of a material harder than the base material of the head body 1. Therefore, the wear of the side wall portion 11b due to scraping of the chips is suppressed, and the durability as a boring head is greatly improved.

  Therefore, it is necessary to select a material having a higher hardness as the material of the wear-resistant member 3 according to the base material type of the head body 1, but the head body 1 may be general steel or tool steel. For example, cemented carbides mainly composed of tungsten carbide such as WC-Co, sintered ceramics such as alumina, silicon nitride and boron nitride, cermets such as TiC / N, microcrystalline diamond sintered bodies, etc. Is preferred.

  In addition, although the high hardness material as described above is generally expensive, in the illustrated embodiment, the support block 5 serving as an attachment portion for the head body 1 may be an inexpensive material similar to the base material of the head body 1. Since a high-hardness material only needs to be used for the plate-like wear-resistant member 3, the burden of material costs can be reduced.

  Further, since the support block 5 can be formed of an inexpensive and easy-to-process material as described above, the wear-resistant member 3 can be attached to the head main body 1 by increasing the size and increasing the number of screwed portions as in the embodiment. In addition to increasing the strength, by providing a concave / convex engaging portion such as the locking protrusion 53 with the head main body 1, the positional accuracy of the mounting is improved and the mounting operation is facilitated. Further, as in the embodiment, the support block 5 has side portions 5a and 5b facing the chip discharge ports 11 and 12, respectively, and the wear-resistant member 3 is fixed to one side portion 5a, and the other side By forming the cutting blade mounting seat 13a in the side surface portion 5b, it is possible to avoid the complication of the structure of the mounting portion of the wear resistant member and to functionally arrange the wear resistant member and the cutting blade.

  In the above embodiment, a boring head including five cutting blades 21 to 25 made of a three-way symmetrical throw-away tip is exemplified, but the present invention has one cutting blade (one chip discharge hole) or three. Applicable to different numbers such as (two chip discharge holes), cutting blades with brazing type, cutting blades with double-symmetry (one update) throw-away tip is there. Therefore, in order to improve the straightness of drilling, a boring head (generally a boring head using a throw-away tip) whose cutting edge main part of the cutting blade responsible for cutting at the center of the cutting radius is inclined to the right hand side. ), The curl of the chips makes it easier for the chips to rub against the side wall portion adjacent to the cutting blade mounting portion of the chip discharge port, so that the application effect of the present invention is particularly great.

  Further, the boring head of the present invention has a rear tube portion for use in a single tube system for supplying coolant to a cutting portion through a gap between a single tubular boring bar and a cutting hole, or a boring bar having a screw at a tip portion. An internal thread type having an internal thread on the inner periphery is also included. In addition, about a chip discharge port, there are various shapes, such as a fan shape and a deformation | transformation ellipse, not only the rectangle which was illustrated by embodiment. Accordingly, the side wall portion on which the wear-resistant member is provided is not limited to a flat shape but may be a curved surface, and various shapes can be set for the wear-resistant member and the support block. In addition, the detailed configuration of the boring head according to the present invention can be variously modified in addition to the embodiment.

The boring head which concerns on one Embodiment of this invention is shown, (A) is a top view, (B) is a front view. The head main body of the boring head is shown, in which (A) is a plan view and (B) is a cross-sectional view taken along line BB in (A). The support block which fixed the wear-resistant member used for the boring head is shown, (A) is a perspective view, (B) is a top view, (C) is an arrow sectional view of the CC line of (B). It is a vertical side view of the front part of the head main body which attached the support block. The conventional boring head is shown, (A) is a plan view and (B) is a front view.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Head main body 1a Front end part 10 Chip discharge path 11 Chip discharge port 11a, 11b Side wall part 12 Chip discharge port 12a Side wall part 13, 13a Cutting blade mounting seat 14, 14a Screw insertion hole 2 Cutting edge 2a Long side (cutting edge main part )
21 to 25 Cutting blade 3 Wear resistant member 5 Support block 5a, 5b Side face 6 Block mounting seat 8 Mounting screw H1 Boring head

Claims (5)

  A chip discharge port communicating with the chip discharge passage is opened at the front end portion of the substantially cylindrical head main body, the inside of which forms a chip discharge passage, and a cutting blade is attached to a side wall portion along the radial direction of the chip discharge port. A wear-resistant member made of a material harder than the base material of the head main body is attached to at least the front edge side of the side wall portion along the substantially radial direction adjacent to the side wall portion to which the cutting blade is attached in the chip discharge port. Boring head.   A pair of chip discharge ports disposed substantially opposite to each other in the radial direction, and a plurality of cutting blades that are distributed and attached to the side wall portions of both chip discharge ports and share the cutting radius. The boring head according to claim 1, wherein a cutting blade main portion of a cutting blade responsible for cutting has a right-handed inclination, and the wear-resistant member is attached to a chip discharge port facing the most central cutting blade.   The boring head according to claim 1 or 2, wherein the plate-like wear-resistant member is fixed to a side surface portion of the support block, and a block mounting seat for screwing the support block is recessed on the head main body side.   The head main body includes a pair of chip discharge ports arranged substantially opposite to each other in the radial direction, the support block has side portions respectively facing both chip discharge ports, and the wear-resistant member is fixed to one side surface portion thereof, The boring head according to claim 3, wherein a cutting blade mounting seat is recessed in the other side surface portion. The boring head according to any one of claims 1 to 4, wherein the cutting blade comprises a throw-away tip.

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