JP4260584B2 - Drilling tool - Google Patents

Description

  The present invention relates to a hole machining tool used for machining, for example, a valve hole opening (valve seat) in a cylinder head of an engine into a predetermined shape.

  As a hole machining tool for machining such an opening of a valve hole, the inventors of the present invention, for example, in Patent Document 1, use a cutting blade inclined with respect to the axis on the outer periphery of a tool body rotated around the axis. With the reamer extending along the axis line provided at the tip of the tool body, the inner diameter of the valve hole is processed with a predetermined accuracy by the reamer, and the cutting blade that rotates coaxially with the reamer, A valve seat surface that a valve head abuts on the opening of the valve hole is formed coaxially with the valve hole.

Thus, according to the hole machining tool described in Patent Document 1, conventionally, a complicated slide mechanism or the like is required because the cutting blade is slid along the inclination to process the valve seat surface. Along with this, machine tools require a drive mechanism that drives the slide mechanism, and what can only be processed with a dedicated one can be processed with a general-purpose machining center, etc. It is possible to efficiently cope with the increase in the number of valves in the engine.
JP 2002-59313 A (page 2-10)

  By the way, in such a hole drilling tool, the chatter vibration is generated because the tool body is swung to the side opposite to the cutting edge due to the back component force of the cutting resistance acting on the cutting edge at the time of machining. However, there is a possibility that the processing accuracy is deteriorated. However, in order to suppress the swing of the tool body due to such a back force, a guide pad having an outer peripheral surface that can be slidably contacted with the processing surface processed by the cutting blade is provided on the outer periphery of the tool main body by brazing or the like, It is conceivable to perform the processing while guiding the tool body with this guide pad.

  Therefore, in a hole machining tool in which a plurality of cutting blades are installed, there is a problem that chatter vibration generated in the tool body cannot be suppressed depending on the installation location of the guide pad, and the accuracy of the machining surface cannot be ensured.

  The present invention has been made under such a background. As described above, in a machine tool such as a machining center, even in a hole machining tool having a plurality of cutting blades, chatter vibration generated in the tool body is suppressed, and the machining surface The purpose is to ensure the accuracy.

According to the first aspect of the present invention, a cutting blade is provided on the outer periphery of the tool body rotated about the axis, a pad having a guide surface is provided , and a multi-stage is provided at the opening of the valve hole using the tool body. In the drilling tool that forms a conical surface , the tool body is provided with a plurality of cutting blades around the axis, and the pads are fixed to the side opposite to the cutting blades with respect to the axis. One of the cutting blades is used as a reference cutting blade, and the clearance of the rotation trajectory between the guide surface of each pad and the reference cutting blade is determined based on the position of the reference cutting blade. It is characterized by being installed so as to gradually increase in the direction opposite to the tool rotation direction around the axis.

  In the drilling tool according to the present invention, the pad is spirally fixed on the outer periphery of the tool, and supports the tool main body in a long range in the axial direction. In addition, the pad is fixed to the tool body and the guide surface is difficult to be displaced.

  According to a second aspect of the present invention, in the drilling tool according to the first aspect, the guide surface of each pad is the smallest of the angles formed by the respective cutting blades and the axis with respect to the axis. It is fixed so that it may slidably contact with the cutting surface cut by the reference | standard cutting blade which makes an angle.

  In such a hole drilling tool, a large back force is generated at the cutting edge having the smallest cutting angle with respect to the axis during machining, and the guide surface is in sliding contact with the machining surface cut by the cutting edge. Therefore, each guide surface receives a stress that efficiently cancels the back component force from the cutting surface.

  According to a third aspect of the present invention, in the drilling tool according to the first aspect, the guide surface of each pad is the second of the angles formed by the respective cutting blades and the axis with respect to the axis. It is fixed so as to be in sliding contact with a cutting surface to be cut by a reference cutting edge having a small angle.

  In such a hole drilling tool, the guide surface is disposed so as to be in sliding contact with the valve seat surface that is a cutting surface cut by the cutting blade having the second smallest angle, and the tool body is supported. The cutting edge that cuts the valve seat surface is less likely to shake.

According to the present invention, in a tool having a plurality of cutting blades and a plurality of pads, the clearance of the pad relative to the rotation trajectory of the reference cutting blade is gradually increased around the axis, thereby generating chatter that occurs in the tool body. Vibration can be suppressed and machining accuracy can be improved.
Furthermore, since the pad is fixed to the tool main body, the guide surface surely comes into sliding contact with the cutting surface, and the tool main body can be supported.

  1 to 5 are diagrams showing a first embodiment of the present invention.

  Here, as shown in FIG. 1 and FIG. 2, in the present embodiment, the tool body 1 has a substantially multi-stage cylindrical shape with the axis O as the center, and the rear end portion of the drilling tool is the above machining center or the like. The mounting portion is provided with a mounting mechanism such as HSK to be detachably mounted on the spindle of the machine tool, and the cutting edge 3 on the opposite sides of the outer periphery of the tip portion having a small diameter with the axis O interposed therebetween. Cutting tips 4 (4A to 4C) on which (3A to 3C) are formed and pads 6 (6A to 6C) on which guide surfaces 5 (5A to 5C) are formed are provided.

In FIG. 3, the cutting edge tips 4... (4A to 4C) are made of a hard material such as cemented carbide and have a substantially triangular flat plate shape. Further, as shown in FIG. 1, the cutting edge tip 4 is detachably attached to the cartridge 9 by a known clamping means, and this cartridge 9 is attached to the tool body 1 by a clamp screw 10 so that it is obliquely attached. The cut-out 1 corner is attached to the tool main body 1 with the tool tip outer peripheral side facing. The cutting edge 3 is formed at the corner of the cutting edge tip 4 so that the rotation trajectory around the axis O moves toward the outer peripheral side as it goes to the tool rear end side with respect to the axis O. It will be inclined and arranged.
On the other hand, the pad 6 is also formed of a hard material such as cemented carbide in the present embodiment and has a substantially axial shape with a square cross section, and a cross section extending in parallel to the axis O formed on the outer periphery of the tip of the tool body 1. It is inserted and seated in a “U” -shaped mounting groove so that its longitudinal direction runs along.
And this pad 6 ... (6A-6C) is being fixed to the tool main body 1, and the position of guide surface 6 ... (6A-6C) is being fixed.

FIG. 3 is a diagram illustrating the trajectories of the cutting edges 3A to 3C when the tool body 1 makes one rotation at a fixed position.
Here, as shown in FIG. 3, a plurality of (three in the present embodiment) cutting blades 3 having different inclination angles (cutting angles) α to γ with respect to the axis O at the tip of the tool body 1. (3A to 3C) are formed in the circumferential direction, and are slightly shifted in the direction of the axis O, and are formed in the cutting edge tips 4A to 4C so that their respective rotation trajectories are continuous in a broken line shape. It is arranged.

  In the first embodiment, pads 6... (6A to 6C) are fixed to the outer periphery of a plurality of tools on the opposite side of the cutting blade tips 4. Moreover, in this 3rd Embodiment, 3A of cutting blades are made into the reference cutting blade among cutting blades 3 ... (3A-3C).

Here, as shown in FIG. 2, the angles θC, θB formed by the guide surfaces 5C, 5A, 5B of the pads 6C, 6A, 6B and the reference cutting edge 3A in the direction opposite to the tool rotation direction T around the axis O. , ΘA are gradually increased (for example, 60 °, 180 °, 300 °).
In FIG. 4, l is the length of the locus of the cutting edge 3A when the tool body 1 makes one rotation at a fixed position, and Ω indicates the lead angle. L indicates the feed amount of the cutting blade 3A when the tool body 1 rotates once. That is, FIG. 4 shows the positions of the guide surfaces 5A to 5C on the outer periphery of the tool body 1 with reference to the reference cutting edge 3A , the circumferential lengths 1A, 1B, and 1C, the reference cutting edge 3A, and the guide surface 5A. This is expressed by using XA, XB, and XC distances in the axis O direction (clearance of the rotation trajectory between the guide surface and the reference cutting edge) with ˜5C.
Therefore, the guide surface 5A of the pad 6A is on the outer periphery of the tool body 1 at a position of length 1A from the cutting edge 3A in the direction opposite to the tool rotation direction T, and from the cutting edge 3A to the axis O direction of the tool body 1 It is installed at a position of length XA on the rear end side.
Here, the guide surface 5B of the pad 6B is on the outer periphery of the tool body 1 at a position having a length 1B in the direction opposite to the tool rotation direction T from the cutting edge 3A, and the axis O of the tool body 1 from the cutting edge 3A. It is installed at a position of length XB on the rear end side in the direction.
Further, the guide surface 5C of the pad 6C is a position having a length 1C from the cutting edge 3A in the direction opposite to the tool rotation direction T on the outer periphery of the tool body 1, and the direction of the axis O of the tool body 1 from the cutting edge 3A. It is installed at the position of the length XC on the rear end side.
Here, XA to XC indicate clearances of rotation trajectories between the pads 6A to 6C and the cutting edge 3A which is the reference cutting edge.
Further, the lengths lA to 1C in the direction opposite to the tool rotation direction T and the lengths XA to XC on the rear end side in the axis O direction of the tool body 1 are proportional to each other.
That is, on the outer periphery of the tool body 1, the pad 6A, the pad 6B, and the pad 6C are installed spirally from the tip end side of the tool body 1, and the valve seat surface S (the cutting with the second smallest cutting angle with respect to the axis O) is performed. The pads 6A to 6C are fixed so as to be in sliding contact with the surface.

FIG. 5 shows the trajectory between the cutting edge 3A and the pads 6A to 6C when the valve hole is machined. The clearance XA between the guide surface 5A and the relief surface R1, the guide surface 5B and the valve seat. The clearance XB with the surface S and the clearance XC between the guide surface 5C and the clearance surface R2 are formed so as to be gradually longer in the order of XC, XA, and XB.
Further, the guide surface 5A of the pad 6A has an inclination angle α with respect to the axis O, the guide surface 5B of the pad 6B has an inclination angle α with respect to the axis O, and the inclination angle of the guide surface 5C of the pad 6C with respect to the axis O. Is fixed to be α.
That is, the guide surfaces 5A to 5C are fixed so that the angle formed between the guide surfaces 5A to 5C and the axis O and the angle formed between the cutting edge 3A and the axis O are both α.
That is, all of the guide surfaces 5A to 5C of the pads 6A to 6C are formed so as to be in sliding contact with the valve seat surface S to be cut by the cutting blade 3A.

Using the tool main body 1 configured as described above, a multi-stage conical surface is formed at the opening of the valve hole.
Even when a back component force is generated in the cutting blades 3A to 3C at the time of machining the valve hole, the guide surfaces 5A to 5C support the tool body 1, and the back component force generated in the cutting blades 3A to 3C is offset. It is possible to prevent chatter vibrations from occurring in the tool body 1.
In particular, during machining, a large back force is generated in the cutting blade 3A. In this embodiment, the guide surfaces 5A to 5C of the pads 6A to 6C are flank R1 cut by the cutting blade 3A. It is formed so as to be slidably contacted. For this reason, the guide surfaces 5A to 5C are likely to be stressed to cancel back force generated in the cutting edge 3A, and chatter vibration is unlikely to occur in the tool body 1.
Further, in the present embodiment, since the pads 6A to 6C are fixed to the tool body 1, the positions of the pads 6A to 6C do not vary even during processing, and the positions of the guide surfaces 5A to 5C, Since the angle with respect to the axis O is not displaced, chatter vibrations can be prevented from occurring in the tool body 1.
In the present embodiment, since the plurality of pads 6A to 6C are formed in the direction of the axis O of the tool body 1, the entire tool body 1 can be reliably stabilized.
In the present embodiment, the guide surfaces 5A to 5C of the pads 6A to 6C are fixed on the outer periphery of the tool body 1 while being slightly shifted from YA to YC from the line set by the lead angle Ω. However, it is not limited to this case. That is, the positions of the guide surfaces 5A to 5C may be appropriately determined in the vicinity of the straight line according to the cutting conditions such as the workpiece material and the cutting feed amount.

  In the present embodiment, the pads 6A to 6C are fixed to the tool body 1 with screws or the like. The means for fixing the pads 6A to 6C to the tool body 1 may be any means as long as it can be fixed to the pads 6A to 6C without using screws.

Here, FIG. 6 shows a second embodiment of the present invention. In this figure, components common to those shown in FIGS. 1 to 5 are given the same reference numerals. The description is omitted.
Here, FIG. 6 is a diagram showing the trajectory of the cutting blade 3B and the pads 6A to 6C when the tool body 1 is rotated once at a fixed position.
In the present embodiment, as shown in FIG. 6, the guide surfaces 5A to 5C are formed so as to be substantially in contact with the valve seat surface S processed by the cutting blade 3B.
Further, the guide surfaces 5A to 5C are fixed so that the clearances XA, XB, XC of the valve seat surface S cut by the cutting blade 3B coincide with each other.
Further, the angle formed between the guide surfaces 5A to 5C and the axis O is fixed so as to coincide with the angle α formed between the cutting edge 3A and the axis O.
That is, in this embodiment, the pads 6A to 6C are fixed so that the guide surfaces 5A to 5C are in sliding contact with the flank R1 (the cutting surface having the smallest cutting angle with respect to the axis O).
In the present embodiment, the cutting blades 3A to 3C are formed as shown in FIG.

  When the multi-stage conical surface is formed in the opening of the valve hole using the tool body 1 configured as described above, the tool body is formed by the plurality of pads 6A to 6C as in the first embodiment described above. Since 1 is supported, it is possible to prevent chatter vibrations from occurring in the tool body 1.

According to the present invention, in a tool having a plurality of cutting blades and a plurality of pads, the clearance of the pad relative to the rotation trajectory of the reference cutting blade is gradually increased around the axis, thereby generating chatter that occurs in the tool body. Vibration can be suppressed and machining accuracy can be improved.
Furthermore, since the pad is fixed to the tool main body, the guide surface surely comes into sliding contact with the cutting surface, and the tool main body can be supported, so that industrial applicability is highly recognized.

It is a side view which shows the 1st Embodiment of this invention. It is the front view which looked at the embodiment shown in Drawing 1 from the axis line O direction tip side. It is a figure which shows the rotation locus | trajectory of several cutting-blade chip | tip 4A-4C of embodiment shown in FIG. It is a figure which shows arrangement | positioning of a reference | standard cutting blade and a pad in the hole drilling tool which concerns on 1st Embodiment of FIG. It is a rotation locus | trajectory of the guide surfaces 5A-5C of the pads 6A-6C of 1st Embodiment shown in FIG. It is a figure which shows the locus | trajectory of a pad and a cutting blade in 2nd Embodiment.

Explanation of symbols

1 Tool body 3 (3A to 3C) Cutting edge 4 (4A to 4C) Cutting edge tip 5 (5A to 5C) Guide surface 6 (6A to 6C) Pad O Axis α, β, γ of the tool body 1 Cutting edge 3, Tilt angle with respect to the axis O of 3A, 3B, 3C

Claims (3)

A drilling tool in which a cutting edge is provided on the outer periphery of a tool body rotated about an axis, a pad having a guide surface is provided , and a multi-stage conical surface is formed in an opening of a valve hole using the tool body In
The tool body is provided with a plurality of cutting blades around the axis, and the pad is fixed to the side opposite to the cutting blades with respect to the axis. One of the cutting blades And the clearance of the rotation locus between the guide surface of each pad and the reference cutting edge is gradually increased in the direction opposite to the tool rotation direction around the axis with respect to the position of the reference cutting edge. Hole drilling tool characterized by being installed to be
The hole drilling tool according to claim 1,
The guide surface of each pad is fixed so as to be in sliding contact with a cutting surface to be cut by a reference cutting blade having the smallest angle among the angles formed by the cutting blade and the axis with respect to the axis. Hole drilling tool characterized by that. The hole drilling tool according to claim 1,
The guide surface of each pad is fixed so as to be in sliding contact with a cutting surface to be cut by a reference cutting blade having the second smallest angle among the angles formed by the cutting blades and the axis with respect to the axis. A hole drilling tool characterized by

Images