JP4353068B2 - Cutting head replaceable cutting tool - Google Patents

Description

  The present invention relates to a cutting head exchangeable cutting tool in which a cutting head provided with a cutting blade can be detachably attached to a shank.

For cutting a metal material or the like, a cutting head exchangeable cutting tool is used in which a cutting head having a cutting edge can be detachably attached to a shank. In the cutting head exchangeable cutting tool, cutting heads of various shapes can be attached, so that there is an advantage that various cutting processes can be performed with one shank.
In this type of cutting tool, it is necessary to firmly fix the cutting head so that it does not come off during cutting, and many screws are used to obtain the mounting strength. In the case of the used one, there is a problem that the replacement of the cutting head is very troublesome and the number of parts increases and the manufacturing cost increases.

  In addition, as one for fixing the cutting head with a single screw, a configuration is proposed in which the screw is inserted from the rear end of the hollow shank and the cutting head fitted to the tip of the shank is fixed (patent) Reference 1). In the cutting head exchangeable cutting tool having the above-described configuration, the cutting head can be fixed by operating a single screw, so that the cutting head replacement operation is relatively easy, the number of parts is small, and the manufacturing cost is reduced.

  However, in the cutting head exchangeable cutting tool having the above-described configuration, the cutting head is fixed in the vicinity of the axial center of the shank. Therefore, there is a concern that the cutting head may rotate due to cutting resistance during cutting. In the cutting head exchangeable cutting tool having the above-described configuration, the cutting head is attached and detached by screw tightening operation on the rear end side of the shank. For example, when the shank is held by a cylindrical holder There was a problem that the cutting head could not be replaced as it was.

In view of this, there has been proposed a technique in which the cutting head is fixed by a clamp screw provided at the tip of the shank (Patent Document 2). FIG. 10 shows a cutting head exchangeable cutting tool described in Patent Document 2.
The cutting tool 1 includes a cutting head 2, a shank 3, and a clamp screw 4. An attachment portion 6 is provided on the base end side of the cutting head 2, and a groove 8 that is inclined with respect to a direction orthogonal to the tool axis is formed on the side surface of the attachment portion 6. A recess 9 is provided at the tip of the shank 3, and a screw hole 11 is formed in the side surface of the shank 3.

The cutting head exchangeable cutting tool 1 having the above configuration is held by a holder of a machine tool in a state where the cutting head 2 is mounted and fixed to the shank 3, and is used for cutting.
In the cutting head exchangeable cutting tool 1 having the above-described configuration, the mounting portion 6 of the cutting head 2 is fitted into the recess 9 formed at the tip portion of the shank 3, and the groove 8 and the shank 3 provided in the mounting portion 6. The cutting head 2 is fixed to the shank 3 by aligning the position of the screw hole 11 provided in the screw hole 11 and screwing the clamp screw 4 into the screw hole 11.

In the cutting head exchangeable cutting tool 1 having the above-described configuration, the cutting head 2 can be attached and detached by operating the clamp screw 4 screwed to the side surface of the shank 3, so that the cutting tool 1 can be held by the holder. The cutting head 2 can be replaced.
Further, in the cutting head exchangeable cutting tool 1 having the above-described configuration, the clamp screw 4 is inserted and fixed in the groove 8 formed in the mounting portion 6 of the cutting head 2, so that the cutting head is cut by the cutting resistance during cutting. 2 can be prevented from rotating.
Further, in the cutting head exchangeable cutting tool 1 having the above-described configuration, the clamp screw 4 is inserted into the groove 8 formed obliquely in the mounting portion 6 of the cutting head 2, so that the cutting head 2 is drawn toward the shank 3 side. Thus, the cutting head 2 can be prevented from moving toward the tip in the axial direction during cutting.
Japanese Patent Laid-Open No. 06-170615 International Publication No. 03/006194 Pamphlet

However, in the cutting head replaceable cutting tool 1 having the above-described configuration, when the cutting head 2 is replaced, the replacement cannot be performed unless the clamp screw 4 is completely removed, which is troublesome and the clamp screw 4 is lost. There is a possibility that when the clamp screw 4 is lost, the cutting tool 1 cannot be used.
The present invention has been made in view of the above situation, and an object thereof is to provide a cutting head exchangeable cutting tool in which the cutting head is firmly fixed and the cutting head can be easily replaced without removing the clamp screw. It is what.

  In order to solve the above-mentioned problem, the present invention comprises a cutting head having a cutting edge provided at a distal end portion and a shank for holding the cutting head, and an attachment portion provided at a base end portion of the cutting head comprises: A cutting head exchangeable cutting tool that is fitted in a recess formed at the tip of the shank and is detachably mounted. The screw and taper at the tip of the shank so as to cross the recess The screw portion is inserted into a screw hole formed at the tip of the shank so as to open to the inner peripheral surface of the recess, while the tapered portion is connected to the screw portion. A conical shape having a coaxial central axis and having a diameter reduced toward the screwing direction of the screw part, the screw part being positioned in the recess in a state of being screwed into the screw hole, and the mounting part The clan A pressed surface that is pressed against the inner wall side of the recess by the tapered portion is formed by screwing a screw, and the pressed surface is opposed to the tapered portion of the clamp screw located in the recess. The flat portion extends from the distal end side to the proximal end side of the mounting portion so as to come into contact with the tapered portion along a conical generatrix formed by the tapered portion.

In the cutting head exchangeable cutting tool having the above-described configuration, when the clamp screw is screwed in, the tapered portion of the clamp screw approaches the pressed surface of the mounting portion and presses the pressed surface, and the conical bus formed by the tapered portion Since the mounting portion of the cutting head is sandwiched by the inner wall surface of the recess, the cutting head can be fixed, and the cutting head can be prevented from rotating during the cutting process. In addition, by loosening the clamp screw, the taper portion of the clamp screw moves backward with respect to the pressed surface, and a gap is formed between the taper portion of the clamp screw and the pressed surface of the cutting head, so the clamp screw is removed. Without changing the cutting head.
Therefore, it is possible to provide a cutting head exchangeable cutting tool in which the cutting head is firmly fixed and the cutting head can be easily replaced without removing the clamp screw. With the cutting head exchangeable cutting tool configured as described above, the cutting head is firmly fixed, so that the cutting accuracy is improved, and the cutting head can be replaced without removing the clamp screw, improving work efficiency and losing the clamp screw. There is no risk of doing so.

  In addition, the pressed surface of the mounting portion of the cutting head is an inclined plane that gradually recedes toward the tip side of the cutting head, so that the cutting head is pulled to the shank side by screwing a clamp screw. Therefore, the cutting head can be more firmly fixed, and it is possible to prevent the cutting head from rattling or moving in the axial direction during cutting. Therefore, more accurate and stable cutting can be achieved.

  Further, at least one of the tapered portion of the clamp screw and the pressed surface of the attachment portion of the cutting head is formed in a shape in which a central portion in the screwing direction of the clamp screw is recessed with respect to both end portions. As a result, the cutting head is fixed at the three points of the tip and rear ends of the tapered portion and the inner wall surface of the recess in the cross section across the recess, so that the cutting head is more stable. The cutting head can be reliably prevented from being rotated by the cutting resistance at the time of cutting.

An embodiment of the present invention will be described with reference to FIGS.
The cutting head exchangeable cutting tool 21 includes a cutting head 23 provided with a cutting edge 22, a shank 24 that holds the cutting head 23, and a clamp screw 25.
The cutting head 23 is made of a steel material, and includes a head portion 30 and an attachment portion 31 formed in a substantially semi-cylindrical shape that extends integrally from the base end side of the head portion 30.

  The head portion 30 is formed in a substantially cylindrical shape whose outer shape is centered on the axis L. However, as shown in FIG. 3, the tip portion is cut out in a substantially L shape when viewed from the side, and in plan view. 2 is also cut out in a substantially L shape as shown in FIG. 2, and these cutout portions function as chip pockets for discharging cutting waste during cutting. A surface 32 that extends substantially parallel to the axis L of the cylinder that forms the outer shape of the head portion 30 when viewed from the side is formed on the tip side of the head portion 30 thus cut out. A concave portion is formed in the portion, and a cutting blade tip 33 having a substantially parallelogram shape in plan view and having the cutting blade 22 made of a hard material such as cemented carbide is attached to the concave portion by a mounting screw 34. Yes.

  On the other hand, the semi-cylinder formed by the attachment portion 31 has a radius smaller than that of the cylinder formed by the outer shape of the head portion 30 with the axis L as the center, and the flat portion thereof is the cutting edge tip 33 of the head portion 30. Is formed so as to extend substantially along the axis L in the same direction (upward in FIG. 3) as the surface 32 to which is attached, and this plane constitutes the pressed surface 35. However, in this embodiment, the pressed surface 35 is an inclined plane that gradually recedes toward the head portion 30 at a constant inclination angle β, and the inclination angle β with respect to the axis L is 0 ° to 10 °. ing. The tip edge of the pressed surface 35 is orthogonal to the axis L.

  The clamp screw 25 is made of a steel material, and includes a screw portion 40 formed at the front end portion, a tapered portion 41 provided behind the screw portion 40, and a head portion 42 formed at the rear end portion. The taper portion 41 has a central axis M coaxial with the screw portion 40 and has a conical shape whose diameter is reduced by a taper angle α toward the distal end direction of the clamp screw 25, provided that the taper portion 41 is screwed in ( At the center of the clamp screw 25 (in the tip direction), there is provided a recess 45 in which the cross section along the central axis M formed in a concave shape with respect to the taper tip 43 and the taper rear end 44 forms a concave curve. It has been. The taper angle α is set to 3 ° to 25 °. The head portion 42 is formed with an outer peripheral surface 46 having a cylindrical surface shape that is one step larger in diameter than the taper portion rear end 43 around the central axis M, and the clamp screw 25 is rotated on the rear end surface. A hole 47 for inserting the tool is provided.

  The shank 24 is made of a steel material and is formed in a substantially cylindrical shape centered on the axis N. The upper and lower portions of the outer periphery are horizontally cut out by a horizontal plane parallel to each other and parallel to the axis N. The tip of the shank 24 is provided with a recess 50 that opens toward the tip, and the recess 50 has a cross-section perpendicular to the axis N having a constant inner diameter centered on the axis N. The semi-cylindrical cylindrical portion formed by the mounting portion 31 of the cutting head 23 is sized to fit.

  A screw hole 51 is formed so as to open to the inner peripheral surface of the recess 50, and the screw hole 51 is formed above the horizontal plane including the axis N parallel to the horizontal plane at the upper and lower portions of the outer periphery of the shank 24. In an orthogonal cross section, it is formed at an angle α / 2 with respect to the horizontal plane so as to approach the horizontal plane from the inner periphery of the recess 50 toward the outer periphery of the shank 24. On the other hand, a through hole 52 having a circular cross section is formed on the inner peripheral surface of the recess 50 opposite to the screw hole 51 so as to be coaxial with the center line of the screw hole 51. The inner diameter of the through hole 52 is set such that the outer peripheral surface 46 of the head portion 42 of the clamp screw 25 can be fitted.

  The above-described cutting head exchangeable cutting tool 21 is held in a holder of a machine tool with the cutting head 23 mounted and fixed to the shank 24, used for cutting, and provided on a cutting edge tip 33. The material to be cut is cut with the blade 22 and the cutting waste is discharged from the notch.

  In the cutting head exchangeable cutting tool 21 described above, the mounting portion 31 of the cutting head 23 is formed in the concave portion 50 formed at the tip of the shank 24, and the cylindrical portion of the outer periphery of the mounting portion 31 is formed on the inner peripheral surface of the concave portion 50. The head portion 30 is inserted in such a manner that the pressed surfaces 35 are parallel to the horizontal plane in a cross-section orthogonal to the axes L and N so that the axes L and N are in close contact with each other. The rear end surface is brought into contact with the front end surface of the shank 24. In this state, when the clamp screw 25 is screwed into the screw hole 51 provided in the recess 50, the screw hole 51 is inclined with respect to the horizontal plane at a half angle of the taper angle α of the taper portion. The taper portion 41 formed on the clamp screw 25 is a generatrix in a cross section perpendicular to the axes L and N of the cone formed by the taper portion 41 with respect to the pressed surface 35 formed on the attachment portion 31 of the cutting head 23. Among them, the bus 60 that faces the pressed surface 35 is arranged in parallel to the pressed surface 35.

  The clamp screw 25 is positioned so that the bus bar 60 has a gap with the pressed surface 35 as shown in FIG. 8 in a state where only the tip portion of the screw portion 40 is screwed into the screw hole 51. In this case, the distance between the bus bar 60 and the horizontal plane is set to be larger than the height from the horizontal plane of the rear end of the mounting portion 31 that is an inclined surface. Therefore, in this state, the cutting head 23 can be attached and detached without interfering with the attachment portion 31 even if the clamp screw 25 is screwed. In this state, the upper edge portion of the outer peripheral surface 46 of the head portion 42 of the clamp screw 25 is left out of the through hole 52.

  From this state, when the clamp screw 25 is screwed in, the tapered portion 41 approaches the pressed surface 35, and on the generatrix 60 in the cross section, the tapered portion front end 42 and the tapered portion rear end 43 are pressed against the pressed surface. 35 is pressed and the pressed surface 35 is pressed toward the inner wall surface of the recess 50. In this state, the outer peripheral surface 46 of the head portion 42 of the clamp screw 25 is fitted into the through hole 52, and the clamp screw 25 is restrained by the screw hole 51 and the through hole 52, and is pressed from the pressed attachment portion 31. Receive reaction force. Therefore, the mounting portion 30 of the cutting head 23 is sandwiched between the conical bus 60 formed by the tapered portion 41 and the inner wall surface of the recess 50, and the cutting head 23 is fixed. Therefore, according to the cutting head exchangeable cutting tool 21 having the above-described configuration, the cutting head 23 is firmly fixed, so that it is possible to improve the cutting accuracy during the cutting process. Further, since the cutting head 23 can be attached and detached without removing the clamp screw 25, the cutting head 23 can be exchanged efficiently and there is no possibility of losing the clamp screw 25.

  In addition, in the present embodiment, the pressed surface 35 is an inclined plane that gradually recedes toward the head portion 30, and the rotation direction X when the clamp screw 25 is screwed in as shown in FIG. Since the portion in contact with the pressing surface 35 faces the shank 24 side, when the clamp screw 25 is screwed, the cutting head 23 is pulled into the shank 24 side, and the rear end surface of the head portion 30 and the front end surface of the shank 24 are Adhered and firmly fixed. Therefore, the cutting head 23 can be more firmly fixed, and the cutting head 23 can be prevented from rattling or moving in the axial direction during the cutting process, and more accurate and stable cutting can be achieved.

  Further, in the present embodiment, the taper portion 41 provided on the clamp screw 25 is recessed at the center portion in the screwing direction (tip direction of the clamp screw 25) with respect to the taper portion front end 43 and the taper portion rear end 44. Since the concave portion 45 having a concave curved section along the central axis M is formed, the taper portion 43 is pressed toward the inner peripheral surface of the concave portion 50 by the tapered portion leading end 43 and the tapered portion rear end 44. Accordingly, the mounting portion 30 of the cutting head 23 is fixed at three points, that is, the tapered portion distal end 43, the tapered portion rear end 44, and the inner wall surface of the recessed portion 50, which are separated from the central axis L of the shank 24. Can be more stably attached, and the cutting head 23 can be more reliably prevented from being rotated by the cutting resistance at the time of cutting. Moreover, since the center part of the taper part 41 is dented and the non-contact part of the taper part 41 and the to-be-pressed surface 35 exists, there is no problem even if the processing precision of this non-contact part is reduced, and manufacturing cost is reduced. be able to.

In the above embodiment, the shank has been described as having a substantially cylindrical shape, but a square shank may be used.
In addition, although the description has been given of the shape of the cutting head in which a cylinder is cut into a substantially L shape, the shape of the cutting head is not restrictive.
Moreover, although the center part of the taper part demonstrated using the concave clamp screw, the center part of the to-be-pressed surface formed in the attachment part may be made into the state where it was dented, and a taper part and The shape where both center parts of the to-be-pressed surface were dented may be sufficient.

  Further, in the present embodiment, the recess 50 is circular with a cross section perpendicular to the axis N having a constant inner diameter centered on the axis N, and the mounting portion 31 has a semi-cylindrical outer shape formed by the mounting portion 31. However, the concave portion 50 and the attachment portion 31 may be tapered, or a tapered portion may be provided on the distal end side of the concave portion 50 and the attachment portion 31. In this case, when the cutting head 23 is drawn to the shank 24 side, the recess 50 and the attachment portion 31 are taper-fitted, so that the attachment strength and accuracy are further improved.

It is a disassembled perspective view of embodiment of this invention. It is a top view of the cutting head of the embodiment of the present invention. It is a side view of the cutting head of the embodiment of the present invention. It is the front view which looked at the cutting head of the embodiment of the present invention from the base end side. It is a side view of the clamp screw of the embodiment of the present invention. It is a side view of the shank of the embodiment of the present invention. It is the figure seen from the front end side of the shank of the embodiment of the present invention. In embodiment of this invention, it is sectional drawing of the state which has not clamped the cutting head. In embodiment of this invention, it is sectional drawing of the state which clamped the cutting head. It is a side view of the conventional cutting head exchange type cutting tool.

Explanation of symbols

21 Cutting Head Replaceable Cutting Tool 23 Cutting Head 24 Shank 25 Clamp Screw 31 Mounting Portion 35 Pressed Surface 40 Screw Portion 41 Taper Portion 50 Recess 51 Screw Hole

Claims (3)

It consists of a cutting head with a cutting edge provided at the tip and a shank that holds the cutting head, and a mounting part provided at the base end of the cutting head fits into a recess formed at the tip of the shank. It is a cutting head exchangeable cutting tool that is detachably mounted,
A clamp screw having a threaded portion and a tapered portion is inserted through the distal end portion of the shank so as to cross the recessed portion, and the threaded portion opens to the inner peripheral surface of the recessed portion. The tapered portion has a central axis that is coaxial with the screw portion and has a conical shape whose diameter is reduced in the screwing direction of the screw portion. While located in the recess in a state of being screwed into the screw hole,
The mounting portion is formed with a pressed surface that is pressed against the inner wall side of the recess by the taper portion by screwing the clamp screw, and the pressed surface is located in the recess. Opposite to the tapered portion of the mounting portion, a flat shape extending from the distal end side to the proximal end side of the mounting portion so as to come into contact with the tapered portion along a conical generatrix formed by the tapered portion. A cutting head exchangeable cutting tool. In the cutting head exchangeable cutting tool according to claim 1,
The cutting head exchangeable cutting tool, wherein the pressed surface of the mounting portion of the cutting head is an inclined plane that gradually recedes toward the tip side of the cutting head. In the cutting head exchangeable cutting tool according to claim 1 or 2,
At least one of the tapered portion of the clamp screw and the pressed surface of the attachment portion of the cutting head is formed in a shape in which a central portion in the screwing direction of the clamp screw is recessed with respect to both end portions. The cutting head exchangeable cutting tool characterized by the above-mentioned.

Images