JP2005186223A - Throwaway drill - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a throwaway drill which can be easily replaced, is excellent in drilling precision, and has a longer service lifetime. <P>SOLUTION: The throwaway drill 1 is composed of a throwaway tip 5 provided with at least two cutting edges 8 on the front end side and an imperfect-circular rear end hole part 7, whose cross-sectional diameter is partially different, at the center of the rear end side, a tool holder 3 having an imperfect-circular front end hole part 6, whose cross-sectional diameter is partially different, at the central part of the front end side, and a nearly bar-like and imperfect-circular coupling member 4 whose cross-sectional diameter is partially different. One end of the coupling member 4 is inserted to the front end hole part 6. The other end of the coupling member 4 is inserted to the rear end hole part 7 of the throwaway tip 5. After that, the inner wall face close to the minimum width of the rear end hole part 7 and the front end hole part 6 and the wall face close to the maximum width of the coupling member 4 are fixed by bringing them into sliding contact with each other by rotating the throwaway tip 5. Consequently, the throwaway tip 5 is mounted attachably/detachably to/from the front end part of the tool holder 3. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a throw-away drill in which a throw-away tip having a rotation axis common to a tool body is detachable.

  Conventionally, as a throw-away drill in which a throw-away tip having a rotation axis common to the tool body can be attached and detached, a screw is inserted from a screw hole provided on the side surface of the tool body, and the screw is pressed and pressed against the side of the throw-away tip to A configuration in which an away tip is fixed to a holder is generally known (see, for example, Patent Document 1).

Also, a screw hole is provided on the back side of the throw-away tip as shown in FIG. 7, and the throw-away tip is pulled into the tool body by screwing from the back side of the mounting surface, as disclosed in Patent Document 2 described later. A configuration in which the throw-away tip is fixed using elastic deformation of the holder is also known.
Japanese National Patent Publication No. 11-500967 Japanese translation of PCT publication No. 2002-501441

  However, the configuration in which the throwaway tip is simply screwed from the side of the tool body as disclosed in Patent Document 1 has the advantage that the throwaway tip can be replaced very easily, but the throwaway tip and the tool body There is a problem that it is difficult to match the central axes of the two and it is difficult to obtain high machining accuracy.

  Further, if the throwaway tip as shown in FIG. 7 is pulled into the tool body, the center axes of the throwaway tip and the tool body can be made to coincide with each other. Each holder must be removed from the tool post, and there is a problem that workability is significantly deteriorated.

  Furthermore, in the configuration utilizing the elastic deformation of the holder as disclosed in Patent Document 2, it is relatively possible to match the central axes of the throw-away tip and the tool body while maintaining good workability. However, since it is necessary to firmly fix the throw-away tip only by the elastic deformation action of the holder, an excessive force is repeatedly applied to a specific part of the holder. As a result, there is a problem that the elastic force of the holder is weakened while the throw-away tip is repeatedly replaced, and the throw-away tip is dropped from the tool body or is damaged. Therefore, the tool holder must be replaced with a new one with a small number of uses, which is extremely uneconomical.

  The present invention has been made in order to solve the above-described problems of the prior art, and in a throw-away drill in which a throw-away tip having a rotation axis common to a tool body can be attached and detached, it is easy to replace and repeat processing. The object is to provide a throw-away drill with high accuracy and long life.

  In order to solve the above-mentioned problem, the throw-away drill according to claim 1 is provided with at least two cutting edges on the front end side, and a rear end hole portion of a non-circular shape having a partially different cross-sectional diameter at the center of the rear end side. A throw-away tip provided, a tool holder provided with a non-circular tip hole portion having a partially different cross-sectional diameter at the center portion on the front end side, and a non-circular shape having a substantially rod shape and a partially different cross-sectional diameter. A throwaway drill comprising a connecting member, wherein one end of the connecting member is inserted into the tip hole portion, and the other end of the connecting member is inserted into a rear end hole portion of the throwaway tip, By rotating the away tip to slidably fix the inner wall surface near the minimum width of the rear end hole portion and the tip hole portion and the wall surface near the maximum width of the connecting member, the throw away tip is fixed to the tool holder. Removable at the tip of It is characterized by being attached to.

  According to this configuration, one end of the connecting member is inserted into the tip hole portion of the tool holder, and the other end of the connecting member is further inserted into the rear end hole portion of the throw-away tip, and the throw-away tip is rotated to rotate the tool holder. Since the center axis can be matched with high accuracy, high machining accuracy can be guaranteed. Further, the throw-away tip can be replaced only by rotating the throw-away tip via the connecting member, and the throw-away drill can be made excellent in workability and with little holder deterioration.

  Moreover, the throw-away drill according to claim 2 is characterized in that a cross-sectional shape of at least a sliding contact surface with the connecting member among the inner wall surfaces of the front end hole portion and the rear end hole portion is a part of an ellipse. .

  According to such a configuration, when the throwaway tip is rotated and the inner wall surface near the minimum width of the front end hole portion and the rear end hole portion and the wall surface near the maximum width of the connecting member are in sliding contact with each other, Since the pressing force gradually increases, the throwaway tip can be reliably fixed, and in addition, the throwaway drill having excellent workability can be obtained.

  The throw-away drill according to claim 3 is characterized in that the cross-sectional shape of the connecting member is an ellipse.

  According to this configuration, when the throwaway tip is rotated, the pressing force when the inner wall surface near the minimum width of the front end hole portion and the rear end hole portion and the wall surface near the maximum width of the connecting member are in sliding contact with each other is reduced. In addition to being able to perform the action of gradually increasing more reliably, the strength of the connecting member can also be maintained over a long period of time.

  According to a fourth aspect of the present invention, the connecting member is made of a material softer than the tool holder.

  According to such a configuration, damage to the tool due to repeated attachment and detachment of the throw-away tip can be concentrated only on the connecting member, and the tool holder body can be used as it is for a long time by replacing only the connecting member. Therefore, it is possible to make a throw-away drill with excellent cost performance.

  The throw-away drill according to claim 5 is characterized in that the minimum width of the cross section of the rear end hole portion on the throw-away tip side is d, the minimum width of the cross-section of the tip hole portion on the holder side is a, and the throw-away tip of the connecting member It is characterized in that d / b ′ <a / c ′, where b ′ is the maximum width of the side section and c ′ is the maximum width of the holder side section of the connecting member.

  According to this configuration, one end of the connecting member is inserted into the front end hole of the holder, and the other end of the connecting member is inserted into the rear end hole of the throwaway tip. When the throwaway tip is further rotated and fixed to the tool holder, the throwaway tip and the connecting member are first slidably fixed, and then The throwaway tip can be securely attached to the tool holder within a short rotation range so that the tool holder and the connecting member are slidably fixed.

  According to the throw-away drill of the present invention, the throw-away tip includes at least two cutting blades on the front end side, and a non-circular rear end hole portion having a partially different cross-sectional diameter at the rear end side center, A tool holder provided with a non-circular tip hole portion having a partially different cross-sectional diameter at the front-end center portion, and a non-circular connecting member having a substantially rod shape and a partially different cross-sectional diameter. A throwaway drill, wherein one end of the connecting member is inserted into the tip hole portion, the other end of the connecting member is inserted into a rear end hole portion of the throwaway tip, and then the throwaway tip is rotated. The throwaway tip can be attached to and detached from the tip of the tool holder by slidingly fixing an inner wall surface near the minimum width of the rear end hole and the tip hole and a wall surface near the maximum width of the connecting member. In the configuration to be attached to Thus, one end of the connecting member is inserted into the tip hole portion of the tool holder, and the other end of the connecting member is inserted into the rear end hole portion of the throw-away tip, and the throw-away tip is rotated and fixed to the tool holder. As a result, the center axis can be matched with high accuracy, so that high machining accuracy can be guaranteed. Further, the throw-away tip can be replaced only by rotating the throw-away tip via the connecting member, and the throw-away drill can be made excellent in workability and with little holder deterioration.

  Embodiments of the present invention will be described below with reference to the accompanying drawings.

  1 to 6 show an embodiment of the present invention, and FIG. 1 is an exploded perspective view of a tip portion of a throw-away drill (hereinafter abbreviated as a drill) according to the first embodiment of the present invention, FIG. 1 is a front view of the tool holder of FIG. 1, FIG. 3 is a bottom view of the throw-away tip (hereinafter abbreviated as “chip”) of FIG. 1, and FIG. 4 is a side view of a connecting member according to the second embodiment of the present invention. 5A is a cross-sectional view taken along the line AA of FIG. 4, FIG. 5B is a cross-sectional view taken along the line BB of FIG. 4, and FIG. 6A is a side view of the connecting member according to the third embodiment of the present invention. 6B is a cross-sectional view taken along the line C-C in FIG. 6A, and FIG. 6C is a cross-sectional view taken along the line D-D in FIG.

  In FIG. 1, the drill 1 by 1st embodiment of this invention becomes a structure by which the chip | tip 5 is detachably mounted | worn via the connection member 4 at the front-end | tip part of the tool holder 3 which has the common rotating shaft 2. In FIG. Yes. Here, a front end hole 6 and a rear end hole 7 are respectively provided at the front end center of the tool holder 3 and the rear end center of the chip 5, and one end of the connecting member 4 is connected to the front end hole 6. The other end is inserted into the rear end hole 7.

  Further, a cutting edge 8 and other cutting edges (not shown) are provided on the tip side of the chip 5. On the other hand, tip surfaces 9 and 10, a rotation transmission wall surface 11, and a clamping wall surface 12 are formed at the tip of the tool holder 3, and these surfaces are rear end surfaces 9 ′ and 10 formed on the rear end side of the chip 5. ', The rotating passive wall surface 11' and the sandwiched wall surface 12 'are brought into contact with each other.

  Here, as shown in FIGS. 2 and 3, the front end hole 6 and the rear end hole 7 have a non-circular shape in which the diameter of the cross section perpendicular to the rotation shaft 2 is partially different. And as shown in FIG.4 and FIG.5, the cross section of the both ends of the connection member 4 also has the shape from which the diameter differs partially, and consists of an elliptical shape here.

  Incidentally, when attaching the tip 5 to the tool holder 3, as shown in FIG. 1, first, one end of the connecting member 4 is first inserted into the tip end hole 6 on the holder side, and then the other end of the connecting member 4 is connected to the tip 5 of the tip 5. Insert into the rear end hole 7. Then, by rotating the throw-away tip 5, the front end hole 6, the rear end hole 7, and the connecting member 4 are engaged with each other.

  Here, as shown in FIG. 2 to FIG. 5, the cross section of both ends of the connecting member 4 is similar to the front end hole 6 and the rear end hole 7, but the minimum width a of the front end hole cross section is a. A maximum width b of the tip hole section, a maximum width c of the rear end hole section, a minimum width d of the rear end hole section, a minimum width a ′ of the connecting member in the chip side section, the connecting member The maximum width b ′ in the chip side cross section, the maximum width c ′ in the holder side cross section of the connecting member, and the minimum width d ′ in the holder side cross section of the connecting member are a ′ <a (b ′ < b), c ′ <c (d ′ <d), and the relationship of a <b ′, c <d ′ is satisfied. By satisfying such a relationship, the connecting member 4 can be locked at a position rotated relative to the holes 6 and 7. Further, by further optimizing these dimensions, the position where the tip 5 is locked is changed to the rotation transmitting wall surface 11, the sandwiching wall surface 12 of the tool holder 3, the rotational passive wall surface 11 ′ of the tip 5, and the sandwiched wall surface 12 ′. Can be adjusted to a position where they are fixed in contact with each other. Here, since the sandwiching wall surface 12 is inclined so as to approach the central axis 2 side toward the tip end side of the tool holder 3, the tip 5 does not come off to the tip end side when the tip 5 is attached.

  Incidentally, the connecting member 4 may have the same cross-sectional shape from the tip side to the holder side as in the first embodiment shown in FIG. 1, or as in the second embodiment shown in FIGS. The cross-sectional shape on the chip side may be different from the cross-sectional shape on the holder side. However, the minimum width d of the hole cross-section on the chip side and the minimum width of the hole cross-section on the holder side may also be used at this time. a, the relationship between the maximum width b ′ of the chip-side cross section of the connecting member and the maximum width c ′ of the cross-section of the connecting member is such that d / b ′ <a / c ′. The chip, the connecting member, and the holder are securely slidably fixed.

  The material of the connecting member 4 is preferably formed of a material softer than the tool holder. For example, when the tool holder is made of cemented carbide or steel, the connecting member 4 is formed of copper, aluminum, brass, or the like. It is desirable that the damage to the tool due to repeated chip mounting / removal operations can be concentrated only on the connecting member, and the tool holder body can be used as it is for a long time by replacing only the connecting member. .

  1 and 4, the depth H1 of the front end hole 6, the depth H2 of the rear end hole 7, the length H1 'of the same cross section on the holder side of the connecting member 4, and the same cross section on the chip side The length H2 ′ satisfies the relationship of H1 ′ <H1 and H2 ′ <H2. By satisfying such a relationship, the front end surfaces 9 and 10 of the tool holder 3 and the rear end surfaces 9 ′ and 10 ′ of the throw-away tip 5 can be reliably brought into contact with each other. It can be fixed stably and firmly.

  Moreover, as shown in FIG. 6, the cross section of the connection member as 3rd embodiment consists of square shape. Even if it is such a shape, the diagonal line in a cross section can play the role as a connection member in this invention by slidably fixing to the said front-end hole part and the said rear-end hole part inner wall.

  As mentioned above, although embodiment of this invention was illustrated, this invention is not limited to embodiment mentioned above, It cannot be overemphasized that it can be made arbitrary, unless it deviates from the objective of invention. For example, the cross-sectional shape of the recess and the connecting member is not limited to an ellipse and a quadrangle, and may be another polygon or a polygon with rounded corners.

It is a disassembled perspective view of the throwaway drill front-end | tip part by 1st embodiment of this invention. It is a front view of the tool holder of FIG. FIG. 2 is a bottom view of the throw-away tip in FIG. 1. It is a side view of the connection member of FIG. It is (a) AA sectional drawing of FIG. 4, (b) BB sectional drawing. It is the (a) side view of the connection member by 3rd embodiment of this invention, (C) CC sectional drawing of (a), (c) It is DD sectional drawing of (a). It is a side view of the conventional throw away drill.

Explanation of symbols

1 Throw away drill (drill)
2 Rotating shaft 3 Tool holder 4 Connecting member 5 Throw away tip (chip)
6, 7 hole
8 Cutting edge 9, 10 Tip surface 11 of tool holder Rotation transmission wall surface 12 Nipping wall surface 9 ', 10' Tip end surface 11 'Rotation passive wall surface 12' Clamped wall surface

Claims (5)

A throw-away tip comprising at least two cutting blades on the front end side, and a non-circular rear end hole portion having a partially different cross-sectional diameter at the rear end side center,
A tool holder provided with a non-circular tip hole part having a partially different cross-sectional diameter at the tip side center part;
A non-circular connecting member that is substantially rod-shaped and has a partially different cross-sectional diameter;
A throwaway drill consisting of
One end of the connecting member is inserted into the front end hole, and the other end of the connecting member is inserted into the rear end hole of the throw-away tip, and then the throw-away tip is rotated and the rear end hole and the The throw-away tip is detachably attached to the tip of the tool holder by fixing the inner wall near the minimum width of the tip hole and the wall near the maximum width of the connecting member by sliding contact and fixing. Throw away drill. 2. The throw-away drill according to claim 1, wherein a cross-sectional shape of at least a sliding contact surface with the connecting member among the inner wall surfaces of the front end hole portion and the rear end hole portion is a part of an ellipse. The throw-away drill according to claim 1 or 2, wherein a cross-sectional shape of the connecting member is an ellipse. The throw-away drill according to any one of claims 1 to 3, wherein the connecting member is made of a material softer than the tool holder. The minimum width of the cross section of the rear end hole is d, the minimum width of the cross section of the tip hole is a, the maximum width of the cross section of the connecting member on the throwaway tip side is b ′, and the maximum width of the cross section of the connecting member on the holder side. The throw-away drill according to any one of claims 1 to 4, wherein d / b '<a / c', where c 'is a large amount.

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