JP2005279855A - Boring cutting tool - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a boring cutting tool reconciling excellent processing performance of cut chips and chattering resistance important in inside diameter machining. <P>SOLUTION: A cutting edge tip 6 and a cut chip pocket 4 located on an upper side of a cutting edge 3 of the cutting edge tip 6 are provided at a distal end of a holder 7 constituting this boring cutting tool. A first sub pocket 1 and a second sub pocket 2 are provided to be located on upper sides of the cutting edge 3 on a holder outer periphery on the cutting edge 3 side of the cutting edge tip 6 and a holder outer periphery on an opposite side in the peripheral direction in relation to the cutting edge 3, respectively. A rib 5 is generated between the sub pockets 1 and 2. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a boring tool for machining an inner diameter hole.

  The boring bar is used for machining the inner diameter hole, so the chip generated by cutting is pinched between the holder and the machined hole, scratching the machined surface, or the dimensional accuracy of the machined hole by biting the chip is high. Problems such as worsening may occur.

  As a countermeasure, the boring bar is provided with a chip pocket for storing and discharging chips. The larger the size of this chip pocket, the more chips can be taken in. However, if the chip pocket is made larger, the cross-sectional area of the head part to which the cutting edge tip is attached will decrease, and the holder will bend easily. There is a problem that so-called chattering easily occurs.

  Therefore, as shown in FIG. 4, the following Patent Document 1 forms a tip pocket 12 on the outer periphery of the blade tip side of the head portion of the holder with the cutting tip 11 attached to the tip, and is further opposite to the cutting edge 13 in the circumferential direction. A concave groove 15 (which comprises two grooves 16 and 17 in the drawing) is provided on the outer periphery of the head portion to reduce the weight of the head portion, and this weight reduction increases the vibration coefficient of the head portion, and this structure is obtained. Therefore, it has been proposed to disperse the cutting force and suppress the displacement of the cutting edge, thereby suppressing chatter vibration.

  However, the boring tool disclosed in Patent Document 1 sacrifices chip disposal because it places importance on chatter suppression.

  That is, in order to suppress the cutting edge displacement to be small, a rib 18 that rises sharply from the end of the rake face 14 is formed in the head portion, and by providing the rib 18, a chip pocket (second recess 19) that is directly connected to the rake face. ) Is very small, and the rib 18 becomes an obstacle to the outflow of chips, so that it is difficult to expect good chip disposal.

  Patent Document 1 also discloses that a cut portion 20 is formed between the groove 15 and the groove 20, but if this cut portion 20 is provided, the cross-sectional area of the rib 18 is reduced, and the effect of suppressing chatter vibration is achieved. descend.

  The present invention has been made in view of the above, and it is an object of the present invention to provide a boring tool that achieves both good processability of chips that are important in inner diameter machining and chatter resistance.

  In order to solve the above-mentioned problems, in the present invention, a boring bit provided with a cutting edge tip and a chip pocket positioned above the cutting edge of the cutting edge tip at the tip of the holder is an object of improvement, A first sub pocket and a second sub pocket are positioned above the cutting edge on the outer periphery of the holder on the cutting edge side of the cutting edge tip and on the outer periphery of the holder opposite to the cutting edge in the circumferential direction. A rib is formed between the sub-pocket and the second sub-pocket.

  In this boring tool, the front surface of the rib is connected to the pocket surface of the chip pocket, and the rib is raised with an inclination angle of 20 to 45 °, or the width of the rib is 20 to 50% of the holder width. It is preferable that the rib is disposed at the substantially central portion of the holder, or that the lengths of the first sub pocket and the second sub pocket are set to 50 to 150% of the holder width (holder diameter).

  In the cutting tool according to the present invention, the finely divided chips generated at the time of machining the inner diameter hole flow into the first sub-pocket provided on the outer periphery of the holder on the blade edge side from the chip pocket that first takes in the chips, It is discharged out of the machined hole through the first subpocket. Further, the chips that are not divided flow into the second sub pocket provided on the outer periphery of the holder on the opposite side in the circumferential direction from the chip pocket, and are discharged to the outside through the second sub pocket. Therefore, it is less likely that the chips are pinched or bitten with the processed hole, and a highly accurate hole can be processed.

  Moreover, although the cross-sectional area of the holder is reduced by installing the first sub-pocket and the second sub-pocket, since the rib exists between both the sub-pockets, the rigidity of the holder due to the reduction of the cross-sectional area, particularly the rigidity against the main cutting force is reduced. The decrease is kept small. Further, since the first sub pocket and the second sub pocket are located above the cutting edge, a decrease in the torsional rigidity of the holder can be suppressed to a small level, thereby ensuring chatter resistance and performing stable machining.

  In addition, what raised the front surface of the rib diagonally with an inclination angle of 20 to 45 ° is easy to flow into the first sub-pocket and the second sub-pocket as the chips are guided to the surface.

  In addition, by setting the rib width to 20% or more of the holder width, it is possible to secure holder rigidity that does not hinder cutting. By setting the rib width to 50% or less of the holder width, the first and second sub-pockets can be secured. It can be avoided that the chip disposal is deteriorated due to being too small.

  Furthermore, if the lengths of the first sub pocket and the second sub pocket are also 50% or more of the holder width, it is possible to ensure the chip disposal that is not problematic, and practically if the length is 150% or less of the holder width. It is possible to secure the holder rigidity without any problem.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of a boring tool according to the present invention will be described below with reference to FIGS. This boring tool is configured by detachably mounting a cutting edge tip (in the figure, a blade tip replaceable tip) 6 on a tip seat provided at the tip of a holder (shank) 7.

  The holder 7 is provided with a chip pocket 4 above the cutting edge 3 of the cutting edge tip. Moreover, the 1st subpocket 1 is provided in the outer periphery of the blade edge | tip 3 side, the 2nd subpocket 2 is provided in the outer periphery of the circumferential direction opposite side with respect to the blade edge | tip 3, respectively, Furthermore, the 1st subpocket 1 and the 2nd subpocket 2 A rib 5 is provided between the two.

  The front surface of the rib 5 is continuous with the pocket surface of the chip pocket 4, and an inclination angle θ = 20 ° to 45 ° with respect to the horizontal line 8 from the position of the chip pocket 4 in FIG. Standing up with a gentle slope.

  Both the first sub-pocket 1 and the second sub-pocket 2 are formed by concave curved grooves that cut out the outer periphery of the holder 7. If the first sub-pocket 1 and the second sub-pocket 2 are formed in a region below the cutting edge 3, the rigidity of the holder 7, particularly the torsional rigidity, is reduced, and chatter vibration is likely to occur during processing.

  The rib 5 formed between the first sub-pocket 1 and the second sub-pocket 2 also has an insufficient effect when the width w is 20% or less of the width W (diameter) of the holder 7 and the rigidity of the holder is lowered. . Further, when the width w of the rib 5 is 50% or more of the holder width W, the volume of the first sub pocket 1 and the second sub pocket 2 is insufficient, and the effect of improving the chip discharging property becomes insufficient. Furthermore, even if the width w of the rib 5 is in the range of 20 to 50% of the holder width W, if the rib 5 is extremely biased toward the blade edge 3 side or the opposite side, the rigidity of the holder 7 is reduced. Therefore, it is preferable that the rib 5 has a width w of 20 to 50% of the holder width W, and is arranged at a substantially central portion in the width direction of the holder 7 as shown in the figure.

  The lengths of the first sub-pocket 1 and the second sub-pocket 2 are also preferably set to 50 to 150% of the width W of the holder 7 in order to achieve both improvement in chip disposal and reduction in holder rigidity.

  The boring tool shown in the figure satisfies the above requirements, so that both chipping and biting due to poor chip disposal performance, which is a problem in inner diameter processing, and chatter vibration due to insufficient rigidity of the holder are suppressed. High-precision and highly efficient inner diameter machining is possible.

The top view which shows embodiment of the boring tool of this invention Fig. 1 shows the boring bar of Fig. 1 in the direction A of Fig. 1. Fig. 1 shows the boring bar of Fig. 1 in the direction B of Fig. 1 Perspective view showing a conventional example of a boring tool

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 1st subpocket 2 2nd subpocket 3 Cutting edge 4 Chip pocket 5 Rib 6 Cutting edge tip 7 Holder 8 Horizontal line

Claims (4)

  In a boring tool in which a cutting edge tip and a chip pocket located above the cutting edge of the cutting edge tip are provided at the tip of the holder, the outer periphery of the holder on the cutting edge side of the cutting edge tip and the circumferential direction with respect to the cutting edge The first sub pocket and the second sub pocket are respectively positioned above the cutting edge and a rib is formed between the first sub pocket and the second sub pocket on the opposite holder outer periphery. A boring tool characterized by   The boring bar according to claim 1, wherein a front surface of the rib is connected to a pocket surface of the chip pocket, and is obliquely raised with an inclination angle of 20 to 45 °.   The boring bar according to claim 1 or 2, wherein a width of the rib is set to 20 to 50% of a holder width, and the rib is arranged at a substantially central portion in the width direction of the holder.   The boring bar according to any one of claims 1 to 3, wherein the lengths of the first sub-pocket and the second sub-pocket are set to 50 to 150% of the holder width.

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