KR200211403Y1 - Indexable boring tool for cutting an internal surface of a small size's hole - Google Patents

Abstract

By holding the cutting insert on the upper surface of the holder simply, accurately, and powerfully, an indexable boring tool for turning internal diameter machining with improved cutting insert stiffness and durability can be improved. Is disclosed. In the indexable boring tool according to the present invention, a plurality of first serrations are formed on the lower surface of the cutting insert, and a dome-shaped protrusion is formed perpendicular to the first serration, and the dome-shaped protrusion and the upper surface of the holder are formed. The V (V) groove corresponding to the first serration and the insertion groove of the second serration were prepared. Therefore, compared with the conventional indexable boring tool, the number of anti-rotation parts is increased, so that stress is dispersed and thereby rigidity is improved. In addition, the positioning of the cutting insert relative to the holder is easy, and errors in mounting can be easily detected and various settings are possible. In addition, it is possible to change the engagement of the cutting insert even when a part of the holder is broken.

Description

Indexable boring tool for cutting an internal surface of a small size's hole}

The present invention relates to an indexable boring tool for turning internal diameter machining, and more particularly, by simply, accurately and powerfully fixing the cutting insert on the upper surface of the holder, showing excellent rigidity and durability, and processing precision and surface roughness. And it relates to an indexable boring tool for turning internal diameter machining that can improve the cutting capacity.

In general, a cutting tool is mainly used for cutting ferrous, nonferrous metals, and nonmetallic materials, and is a tool that is usually mounted on a machine tool to perform cutting to process a workpiece into a desired shape. Typically, such a cutting tool consists of a cutting insert having a cutting edge and a body for holding the cutting insert.

In addition, the cutting tool can be divided into brazing type and indexable type according to the method of fixing the cutting insert to the body, which is permanently fixed by brazing welding the cutting insert to a part of the body. The indexable type is to mount and detach the cutting insert to and from the body using a fixing device provided in the body.

Indexable cutting tools can be easily replaced with new picklings in a short time when the picklings run out of life, a new form that solves the problems of the conventional brazing type cutting tools, ie, the disadvantage of having to regrind the cutting edges for a long time. As a cutting tool of, it is currently used in all parts of cutting tools.

However, indexing requires a clamping mechanism for attaching the insert to a holder or a boring bar, and a space for installing the mechanism must be secured. However, when the space is small, application is difficult. In particular, the cutting tool for internal diameter processing has a limitation in space because the processing is performed in the inner space of the workpiece, and when the workpiece is a small diameter, the space is very narrow, which makes indexing difficult.

On the other hand, there are two ways to cut the metal using a cutting tool, firstly the cutting is performed by contacting the pickled portion of the cutting tool fixed to the rotating metal workpiece. Secondly, the tool with the cutting edge, i.e. the cutting insert, is fixed to the machine tool using the tool holder, and then the workpiece is processed into the desired shape by contacting the fixed workpiece while rotating the cutting tool under such conditions. It is.

Turning is one of the first methods of the metal cutting method, which refers to cutting the workpiece into a desired shape by the linear movement of the cutting tool in the plane including the rotation of the workpiece and its axis of rotation, and transfer of the cutting tool to the workpiece. It is widely used because it can effectively cut various kinds of workpieces according to the movement.

By the way, since the turning tool enters the cutting tool in the axial direction of the workpiece, the boring bar protrusion should be secured from the lathe tool bar, and thus the cutting tool may have an insert breaking property due to vibration caused by the cutting load. Therefore, in the case of internal turning, it is not a problem when the internal diameter of the workpiece is large. However, as the internal diameter decreases, the clamping mechanism is limited, so FGT machining (Forming, Grooving, and Threading) is more powerful than general internal boring. The design is difficult as the clamping mechanism is required and the cutting tool must be smaller due to the space for chip evacuation. As a result, the smallest diameter developed to date is up to φ16, and smaller diameters are using brazing tools or HSS tools.

Recently, a product that can be machined to a minimum working diameter φ8 using a clamping mechanism using screws has been developed by the German company Horn.

4 and 5 show an indexable boring tool developed by the German company Horn. 4 and 5, the conventional indexable boring tool 10 mainly includes a cutting insert 30, a holder 40, and a screw 20 for fixing the cutting insert 30 to the holder 40. do.

The screw insertion hole 41 is formed in the center of the holder 40 according to the prior art, and three fixing grooves 42 are spaced 120 degrees around the screw insertion hole 41 on the upper surface of the holder 40. It is formed radially.

Three protrusions 32 are formed on the lower surface of the cutting insert 30 according to the prior art. The protrusion 32 has a shape corresponding to the shape of the fixing groove 42. A cutout portion 34 protrudes on a radial side of the cutting insert 30, and a screw through hole 31 is formed in the center of the cutting insert 30.

The cutting insert 30 thus formed is fixed on the upper surface of the holder 40 by the screw 20. That is, the screw through-holes 31 and the holders of the cutting inserts 30 aligned in a row with the protrusions 32 formed on the lower surface of the cutting insert 30 positioned in the fixing grooves 42 of the holder 40. The cutting insert 30 is coupled to the holder 40 by inserting the screw 20 into the screw insertion hole 41 of the 40 using a driver (not shown).

The indexable boring tool 10 having such a structure has the advantage of being able to be replaced with a new cutting insert when the cutting portion 32 of the cutting insert 30 wears out and the holder 40 is used. This has the disadvantage that the durability is short and the rigidity of the cutting insert 30 is weak.

In addition, in order to replace the cutting insert 30, the screw 20 must be completely removed from the screw through hole 31 and the screw insertion hole 41 of the holder 40, so that the replacement time is long, and the screw 20 is removed. It is easy to lose it in the removal process, so if the small size screw 20 is mixed with the cutting chip, etc., there is a very difficult problem to find.

In order to solve this problem, Korean Patent Application No. 10-1999-0041874 filed by the applicant of September 29, 1999 discloses an indexable boring tool capable of rapid exchange of cutting inserts.

In the above-described design of the present applicant, serrations corresponding to each other are formed on the lower surface of the cutting insert and the upper surface of the holder to increase the fastening force and make the cutting insert into a semi-circular shape to enable rapid exchange. However, as the shape of the cutting insert has a semicircular shape, tensile stress is locally concentrated, resulting in a decrease in fastening force and rigidity and inability to use in case of partial breakage. Therefore, there is a need to solve this problem.

The present invention has been made to solve the above problems, the object of the present invention is to improve the shape of the lower surface of the cutting insert and the corresponding upper surface of the holder to improve the cutting insert on the upper surface of the holder, The present invention provides an indexable boring tool for turning internal diameter machining that can improve machining accuracy, surface roughness and cutting ability.

Another object of the present invention is to improve the shape of the lower surface of the cutting insert and the corresponding upper surface of the holder, to evenly distribute the tensile stress acting on the cutting insert and to increase the anti-rotation force, thereby improving rigidity. To provide the boring tools.

1 is an exploded perspective view of an indexable boring tool according to the present invention,

FIG. 2 is an enlarged view of the cutting insert shown in FIG. 1;

Figure 3a is a perspective view of the coupled state of the indexable boring tool shown in Figure 1,

Figure 3b is a cross-sectional view of the coupled boring tool shown in Figure 1,

4 is an exploded perspective view of an indexable boring tool according to the prior art, and

5 is a cross-sectional view of the cutting insert shown in FIG.

<Explanation of symbols for main parts of drawing>

10,50: indexable boring tool 20,60: screw

30,70: cutting insert 34,79: cutout

40,80: holder 41,82: screw insertion hole

61: head 62: wrench insertion portion

71: opening 76: dome-shaped protrusion

77: lower surface 81: holder upper surface

83: V groove bottom 84: V groove

85: V (V) groove inclined surface 86: Holder inclined surface

90,96 serration 91,97 serration end face

92,99: serration insertion groove 93a, 93c, 93d: curved surface

93b, 93e, 95: slope 94,98: groove bottom

In order to achieve the above object, the present invention,

It is circular in shape and an opening is formed inside the central portion, and a pair of dome-shaped protrusions and a plurality of first serrations are formed on the lower surface thereof, and the dome-shaped protrusions are perpendicular to the first serrations. Cutting inserts extending in one direction and the domed protrusions and the first serrations are symmetrical with respect to the opening;

A second serration having a shape corresponding to the first groove and the V groove is formed on an upper surface on which the cutting insert is seated, wherein the V groove is perpendicular to the second serration. A cylindrical holder having a screw insertion hole extending in the center of the V-groove and the second serration; And

An indexable boring tool comprising a head having a wrench insertion portion and a screw portion formed under the head, the screw being inserted into the opening and the screw insertion hole when the cutting insert is fixed to the holder. To provide.

As mentioned above, in the indexable boring tool according to the present invention, the cutting insert may be formed in a circular shape and the cutting insert may be firmly detached on the upper surface of the holder by changing the shape of the cutting insert and the upper surface of the holder. And rigidly fixed, it improves rigidity, machining accuracy, surface roughness and cutting capability.

Hereinafter, with reference to the accompanying drawings will be described in more detail the indexable boring tool according to the present invention.

1 is an exploded perspective view of an indexable boring tool according to the present invention.

Referring to FIG. 1, the indexable boring tool 50 according to the present invention mainly includes a cutting insert 70, a cylindrical holder 80, and a screw 60 for fixing the cutting insert 70 to the holder 80. It includes.

First, the cutting insert 70 is mainly produced by cementing the cemented carbide material through a powder metallurgy process, that is, a process such as mold pressure, sintering and grinding. The cutting insert 70 has a circular shape as a whole, and an opening 71 through which the screw 60 can be inserted is penetrated in the vertical direction at the center portion thereof.

FIG. 2 is an enlarged view of the cutting insert shown in FIG. 1.

As shown in FIG. 2, a pair of domed protrusions 76 is formed on the lower surface 77 of the cutting insert 70. The dome shaped protrusions 76 are formed to be symmetrical with respect to the opening 71. At this time, a plurality of first serrations 90 protrude in a direction perpendicular to the dome-shaped protrusions 76 on the lower surface 77 of the cutting insert 70 between the dome-shaped protrusions 76. Is formed. The first serrations 90 are formed to be symmetrical with respect to the opening 71. Preferably, the first serrations 90 protrude from the bottom surface 77 at the same height as the domed protrusion 76. Thus, the end face 91 of the first serrations 90 and the curved top of the domed protrusion 76 have the same height.

The first serrations 90 are for preventing the cutting insert 70 from being rotated by the cutting force during the cutting process using the indexable boring tool 50 and are perpendicular to the first serrations 90. The dome-shaped protrusion 76 assists the first serrations 90 to prevent the cutting insert 70 from rotating by the cutting force during the cutting process using the indexable boring tool 50.

Between the end surfaces 91 of the first serrations 90, the first curved surface 93a, the first inclined surface 93b and the second curved surface 93c are arranged from the end surface 91 to the lower surface 77. Are formed in turn. A first flat groove bottom surface 94 is formed between the second curved surfaces 93c. As a result, the first serration insertion groove having a V shape is formed by the first curved surface 93a, the first inclined surface 93b, the second curved surface 93c, and the first groove bottom surface 94. 92 is provided.

In addition, a third curved surface 93d and a second inclined surface 93e having a constant slope are disposed from the end surface 91 between the end surface 91 and the lower surface 77 of the first serrations 90. It is formed in turn toward face 77. The dome-shaped protrusion 76 perpendicular to the first serrations 90 meets one side of the outer circumferential surface of the opening 71 and the second inclined surface 93e.

Meanwhile, the domed protrusion 76, the bottom surface 77, and the first serrations 90 are connected to a circular peripheral portion 78 that forms a side portion of the cutting insert 70. One side of the peripheral portion 78 is formed with a pickled portion (79) protruding. The cutout 79 extends in a direction perpendicular to the dome-shaped protrusion 76, that is, in the longitudinal direction of the first serrations 90.

Next, the V-groove 84 and the second serration 96 are formed in the upper surface 81 of the holder 80 on which the cutting insert 70 is seated. A screw insertion hole 82 is formed at the center of the holder 80 where the V-groove 84 and the second serration 96 cross each other. The screw insertion hole 82 accommodates the screw 60 for fixing the cutting insert 70 on the upper surface 81 of the holder 80 and corresponds to the length of the threaded portion 66 of the screw 60. It extends in the vertical direction by the depth.

The V-groove 84 is formed perpendicular to the second serration 96. The V-groove 84 enters a predetermined depth from the top surface 81 of the holder 80 and extends horizontally. 83) and a V-groove inclined surface 85 which is inclined at an angle between the V-groove bottom surface 83 and the upper surface 81 of the holder 80.

The second serration 96 corresponds to the first serration 90 protruding from the lower surface 77 of the cutting insert 70. The second serration 96 and the second serration end surface ( 97). In this case, the second serration end surface 97 has a width smaller than the width of the first serration end surface 91. In addition, a holder inclined surface 86 and a flat second groove bottom surface 98 are formed between the upper surface 81 and the third inclined surface 95 of the holder 80. As a result, a second serration insertion groove 99 having a V shape is formed between the upper surface 81 of the holder 80 and the second serration 96.

When the cutting insert 70 is placed on the upper surface 81 of the holder 80, the first serration 90 is inserted into the second serration insertion groove 99, where the first serration 90 is inserted. The first serration end face 91 of s) is located proximate to the second groove bottom surface 98. At this time, the first inclined surface 93b formed between the first serration end surfaces 91 contacts both the third inclined surface 95 and the holder inclined surface 86 of the holder 80, and the first serrations ( The second inclined surface 93e formed between the end surface 91 and the lower surface 77 of the 90 is in contact with the holder inclined surface 86 of the holder 80.

On the other hand, the head 61 of the screw 60 for fixing the cutting insert 70 to the holder 80 is formed with a star wrench insertion portion 62 for inserting a wrench (not shown). The lower portion of the screw head 61 is formed with a threaded portion 66. The screw portion 66 is a portion to be inserted into the screw insertion hole 82, and consists of a male screw.

FIG. 3A is a perspective view of a coupled state of the indexable boring tool illustrated in FIG. 1, and FIG. 3B is a cross-sectional view of a coupled state of the indexable boring tool illustrated in FIG. 1.

3A and 3B, the cutting insert 70 and the holder 80 of the indexable boring tool 50 configured as described above have the opening 71 of the cutting insert 70 being a screw of the holder 80. With the cutting insert 70 positioned above the holder 80 such that the cutting insert 70 is aligned in the vertical direction with the insertion hole 82, the screw 60 is inserted into the opening 71 and the screw insertion hole 82 using a wrench. The threaded portion 66 is inserted to be integrally coupled.

At this time, the first serration 90 and the domed protrusion 76 of the cutting insert 70 inserted into the second serration insertion groove 99 and the V (V) groove 84 of the holder 80 are respectively. Since they are located at right angles to each other, the positioning freedom in the left and right directions is large. In addition, the first serration 90 may be rotated based on the central axis CL of the dome-shaped protrusion 76, and a portion of the dome-shaped protrusion 76 may be inclined surface 85 of the V-groove 84. ), The degree of positioning is large before the screw 60 is inserted into the opening 71 and the screw insertion hole 82.

Therefore, the first serration 90 and the domed projection 76 of the cutting insert 70 can be easily assembled into the second serration insertion groove 99 and the V groove 84 of the holder 80. do. At this time, when the screw 60 is tightened by using a wrench (not shown), the fastening force is transmitted in the axial direction of the holder 80, so that the first inclined surface 93b of the first serration 90 of the cutting insert 70 is provided. ) Is in close contact with the third inclined surface 95 and the holder inclined surface 86 of the holder 80 and the second inclined surface 93e of the first serration 90 is in close contact with the holder inclined surface 86 of the holder 80. . At the same time, a part of the dome-shaped protrusion 76 is in close contact with the V-groove inclined surface 85 of the holder 80. At this time, the first serration end surface 91 of the first serration 90 of the cutting insert 70 and the uppermost portion of the dome-shaped protrusion 76 have a second groove bottom 98 and a V of the holder 80. (V) Maintains a state spaced at a predetermined interval with respect to the groove bottom (83).

In this state, the first serration 90 and the dome-shaped protrusion 76 are perpendicular to each other so that the first serration 90 is positioned at a predetermined position. In addition, the center of the first serration 90 of the cutting insert 70 coincides with the center of the second serration 96 of the holder 80 so that both the right hand and left hand can be interchangeably mounted.

On the other hand, when the screw 60 is fastened so that the cutting insert 70 is correctly set to the holder 80, a part of the domed protrusion 76 is in close contact with a part of the V-groove inclined surface 85 of the holder 80. For this purpose, a deviation by a distance l was provided between the center of the holder 80 and the center of the cutting insert 70. Preferably, deviation was made by a distance l of 0.05 to 0.1 mm.

As described above, in the indexable boring tool 50 according to the present invention, a plurality of first serrations 90 are formed on the lower surface of the cutting insert 70 and the first serrations 90 are formed. The dome-shaped protrusion 76 was formed at an angle of 90 degrees with respect to the upper surface of the holder 80 to have a shape corresponding thereto to increase the anti-rotation effect and obtain the maximum rigidity. Therefore, the indexable boring tool 50 according to the present invention is capable of powerful cutting.

In addition, the mounting between the cutting insert 70 and the holder 80 is easy, and errors in mounting can be easily detected and various settings are possible. In addition, the precise setting between the cutting insert 70 and the holder 80, that is, the positioning accuracy is excellent, the machining precision of the workpiece is improved when performing the cutting process, and the small hole machining causes the vibration caused by the small shank hardness of the holder. Powerful clamping is also available for high speeds, high feeds and high depths of cut, resulting in shorter working times resulting in significant productivity gains.

In addition, most of the protrusion of the bottom surface of the cutting insert 70 is inserted into the holder 80 insertion groove to reduce the occurrence of vibration as much as possible to improve the surface roughness and cutting capacity. In addition, even if the dome-shaped protrusion 76 or the first serration 90 of the cutting insert 70 is partially damaged, it can be used in a manner of changing the fastening portion of the cutting insert 70 to the holder 80. .

Although described above with reference to a preferred embodiment of the present invention, those skilled in the art will be variously modified and modified within the scope of the present invention without departing from the spirit and scope of the present invention described in the utility model registration claims below. It will be appreciated that it can be changed.

Claims (4)

Openings 71 are formed inside the central portion, and a pair of dome-shaped protrusions 76 and a plurality of first serrations 90 protrude from the bottom surface 77, wherein the dome-shaped The upper protrusion 76 extends in a direction perpendicular to the first serrations 90, and the domed protrusions 76 and the first serrations 90 boundary the opening 71. Cutting inserts 70 formed to be symmetrical with each other; A second serration 96 having a shape corresponding to the V groove 84 and the first serration 90 is formed on the upper surface 81 on which the cutting insert 70 is seated. The V-groove 84 extends perpendicularly to the second serration 96 and has a screw insertion hole at the center where the V-groove 84 and the second serration 96 cross each other. A cylindrical holder 80 on which 82 is formed; And A head 61 having a wrench insertion portion 62 formed therein and a threaded portion 66 formed below the head 61, wherein the opening insert is fixed when the cutting insert 70 is fixed to the holder 80; 71) and an indexable boring tool comprising a screw (60) inserted into the screw insertion hole (82). The method of claim 1, wherein the first serrations 90 protrude from the lower surface 77 at the same height as the dome-shaped protrusion 76, and the end surfaces of the first serrations 90. A first curved surface 93a, a first inclined surface 93b and a second curved surface 93c are sequentially formed from the end surface 91 toward the lower surface 77 between the 91 and the second curved surface 93a. A first flat groove bottom surface 94 is formed between the 93c, so that the first curved surface 93a, the first inclined surface 93b, the second curved surface 93c and the first curved surface 93c are formed. Indexable boring tool, characterized in that the first serration insertion groove 92 of the V-shape is provided by the groove bottom surface (94). 3. The lower curved surface (3d) and the second inclined surface (93e) of the lower surface from the end surface (91) between the first serration end surface (91) and the lower surface (77). It is formed toward the 77 in turn, the dome-shaped protrusion 76 meets the outer peripheral surface one side and the second inclined surface 93e of the opening 71, the dome-shaped protrusion 76, the lower surface 77 and The first serration 90 is connected to a circular peripheral portion 78 forming the side portion of the cutting insert 70, the indexer, characterized in that the one side of the peripheral portion 78 is formed by the cutout portion 79 is protruded Boring tools. 4. The V (V) groove bottom surface (83) and the V (V) groove of claim 3, wherein the V groove (84) extends horizontally from the upper surface (81) of the holder (80) and extends horizontally. (V) a V (V) groove inclined surface 85 extends inclined at a predetermined angle between the groove bottom surface 83 and the upper surface 81, the second serration 96, the cutting A third inclined surface that meets the curved surfaces 93a, 93c and the inclined surface 93b of the first serration 90 when an insert 70 is placed on the upper surface 81 of the holder 80 A second serration end surface 97 positioned proximate to the bottom surface 94 of the first groove of the first serration 90 and the upper surface 81 and the third; A holder inclined surface 86 and a flat second groove bottom surface 98 are formed between the inclined surfaces 95. As a result, a V-shaped shape is formed between the upper surface 81 and the second serration 96. Second serenity of Illustration groove indexable boring tool, characterized in that that (99) is provided.