JPH07148605A - Rotation cutting tool for boring - Google Patents

Abstract

PURPOSE:To make an optimum adjustment for each cutting edge position of cutting blades by varying the displacement of a cutting blade correction head to one direction in the rotation cutting tool for boring provided with a plurality of cutting blades which are different in radius for a cutting edge rotating circle. CONSTITUTION:A tool main body 23 is connected to a cutting blade correction head 21. The cutting blade correction head 21 is provided with a base section 40 connected to the rotating shaft of a machine tool, and with a movable section 41 which can be off-centered in the specified radial direction with respect to the base section 40. The tool main body 23 is provided with a plurality of cutting blades 33, 34 and 35. The cutting blades 33, 34 and 35 are located in the axial direction of the tool main body 23 while being separated from one another, and each radius of respective cutting edge rotating circles is made different. Out of the cutting blades 33 through 35, the first cutting blade 33 the work processing length of which is the maximum, is located in the off-centered direction of the cutting blade correction head 21, and the second cutting blade 34 and the third cutting blade 35 are located while being shifted in phase by each specified angle theta1 and theta2 respectively in the circumferential direction of the tool main body 23 with respect to the first cutting blade 33.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotary cutting tool for boring, which is used when boring a work through a cutting blade compensating head provided on a machine tool.

[0002]

2. Description of the Related Art A rotary cutting tool for boring, which is called a boring arbor or a boring cutter, is connected to a rotary shaft of a machine tool as described in, for example, Japanese Utility Model Laid-Open No. 64-60807. A shank is equipped with multiple inserts with cutting blades separated from each other in the axial direction of the shank, and a plurality of holes with different inner diameters such as stepped holes are bored in the machined part that is continuous in the axial direction of the workpiece. Used when doing. In this cutting tool, the radii of the cutting edge rotation circles of the respective cutting blades are different from each other in order to simultaneously cut a plurality of processing parts having different inner diameters.

In the above cutting tool, when the cutting blade is worn to some extent, the position of the cutting edge of the cutting blade is moved in order to compensate for the wear amount so that the radius of the cutting edge rotation circle before the wear can be maintained. Things are also put to practical use. A cutting tool having this type of correction function is shown in FIG.
Like the boring arbor 1 shown in FIG. 1, the tool body 4 is provided on the cutting blade correction head 3 connected to the rotary shaft of the machine tool, and the tool body 4 is provided with a plurality of cutting blades 7, 8, 9 Are arranged so as to be separated from each other in the axial direction. By making the radii of the cutting edge rotation circles of the cutting blades 7, 8 and 9 different from each other, it is possible to cut the inner surface of the processed portion having different inner diameters. These cutting blades 7, 8, 9
Are arranged in the axial direction of the tool body 4.

The correction head 3 has a base portion 10 fixed to a rotary shaft of a machine tool, and a movable portion 11 which is slightly elastically deformable with respect to the base portion 10 in a specific radial direction (direction of arrow A in FIG. 5). And a power unit 12 for driving the movable portion 11 by hydraulic pressure. When a predetermined hydraulic pressure is applied to the power unit 12, the movable portion 11 moves in the direction of arrow A by several μm depending on the magnitude of the hydraulic pressure. The radius of the cutting edge rotation circle of the cutting blades 7, 8 and 9 can be adjusted by displacing about several hundreds of μm. Therefore, according to this correction head 3, when the wear amount of the cutting blades 7, 8, 9 exceeds the allowable value, the movable portion 11 is eccentric in the direction A by a predetermined amount, so that the cutting blades 7, 8, 9 are The amount of wear can be roughly corrected.

An example of the work 15 processed by the boring arbor 1 is a metallic drive system component of a vehicle. The workpiece 15 in the illustrated example is provided with a bearing hole 16 for inserting a bearing and seal holes 17, 18 for inserting an oil seal or the like, and the bearing hole 16 is formed by the first cutting blade 7. Processed and sealed hole 1
7, 18 are processed by the second and third cutting blades 8, 9. Since it is the bearing hole 16 that is most required to be machined, the wear amount of the cutting blade 7 is evaluated after machining, using the measured inner diameter of the bearing hole 16 as a reference.
When the inner diameter of the blade falls below the allowable value, the blade position is corrected by the correction head 3.

[0006]

In the boring arbor 1, since the cutting blades 7, 8 and 9 are aligned in the axial direction of the tool body 4, the cutting edge position of the first cutting blade 7 is adjusted. When the movable portion 11 of the correction head 3 is decentered by a certain amount, the second cutting blade 8 and the third cutting blade 9 are also displaced by the same amount. In other words, all cutting blades 7, 8,
The radius of the blade edge rotation circle 9 increases by the same rate.

In this case, if the cutting blades 7, 8 and 9 are worn by the same amount, no particular problem occurs, but in reality, the machining lengths L1, L2 and L3 by the cutting blades 7, 8 and 9 are Different from each other. For example, when the processing lengths L2 and L3 of the second and third cutting blades 8 and 9 are shorter than the processing length L1 of the first cutting blade 7, the first cutting blade 7 is The amount of wear is larger than that of the cutting blades 8 and 9. Therefore, when the cutting blades 7, 8 and 9 are corrected with the same displacement amount as in the conventional boring arbor 1, the correction amounts of the second and third cutting blades 8 and 9 are unnecessarily large. There was a problem.

Accordingly, an object of the present invention is to provide a rotary cutting tool for simultaneously machining the inner surfaces of a plurality of workpieces having different machining lengths, in which the cutting edge positions of a plurality of cutting blades are optimized by the optimum amount according to the wear amount of each cutting blade. It is to provide a rotary cutting tool for boring that can be adjusted only.

[0009]

The cutting tool of the present invention, which has been developed to achieve the above object, comprises a base portion mounted on a rotary shaft of a machine tool and a movable portion capable of being eccentric to the base portion in a specific radial direction. A tool body provided in a cutting blade correction head having a plurality of cutting blades, and a plurality of cutting blades arranged in positions axially distant from each other in the tool body and having different distances from the tool rotation center to the cutting edge rotation circle. A tool for cutting the inner surfaces of a plurality of workpiece processing parts having different processing lengths by the plurality of cutting blades, wherein the first cutting blade having the largest processing length among the plurality of cutting blades is the cutting blade correction head. It is characterized in that it is arranged in the eccentric direction of the movable part, and the cutting blades other than the first cutting blade are arranged with a predetermined angle displacement in the circumferential direction of the tool body with respect to the first cutting blade.

[0010]

When the boring of the work is carried out by the above cutting tool and the wear of the first cutting blade reaches a predetermined amount, the movable part of the correction head is eccentrically moved by, for example, Δd, so that the tool main body is moved to the first position. The cutting blade is decentered by the above dimension (Δd). In this case, since the first cutting blade is displaced by the above dimension (Δd), the radius of the cutting edge rotation circle of the first cutting blade is increased by the above dimension as it is. For other cutting blades, the radius of the cutting edge rotation circle increases by approximately Δd cos θ according to the angle θ formed by the first cutting blade.

Therefore, by setting the angle appropriately according to the machining length of the work by each cutting blade, the rotary cutting edge circle of the cutting blade other than the first cutting blade when the correction head is eccentric in one direction. It is possible to adjust the radius of to the optimum value. In other words, the correction head is eccentric only in one direction, but the plurality of cutting blades can differ from each other in the amount of change in the cutting edge rotation circle according to the amount of wear of each, and are adjusted to the optimum cutting edge position.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. The cutting machine 20 shown in FIG. 2 has a correction head 21 that is connected to a rotary shaft of a machine tool.
And a rotary cutting tool 22 attached to the correction head 21. The correction head 21 and the rotary cutting tool 22 are
It rotates in the direction of arrow B in FIG. 1 together with the rotary shaft of the machine tool. Reference numeral C indicates the center of rotation of the correction head 21 (tool rotation center). A plurality of (for example, three) chips 30, 31, 32 are attached to the tool body 23. Each chip 3
Each of 0 to 32 has cutting blades 33, 34 and 35.

The correction head 21 includes a base portion 40 fixed to a rotary shaft of a machine tool, and a movable portion 41 that is slightly elastically deformable with respect to the base portion 40 in a specific radial direction (direction of arrow D in FIG. 1).
And a power unit 42 for driving the movable portion 41 by hydraulic pressure. The power unit 42 has a built-in piston 45 movable in the radial direction of the correction head 21, and when the piston 45 is driven by an oil pressure sent from a hydraulic pressure supply source (not shown), a movable part is moved according to the magnitude of the oil pressure. 41 is displaced in the direction of the arrow D in the range of about several μm to several hundred μm.

The tool body 23 is fixed to the movable portion 41 of the correction head 21 by an appropriate fixing means such as a bolt 47. Therefore, when the movable portion 41 is displaced in the direction of arrow D, the tool body 23 moves in the same direction as the movable portion 41.
Eccentricity by the same amount as the cutting blades 33, 34,
35 is displaced in the direction of arrow D.

An example of the work 15 is a machined portion having a bearing hole 16 and a seal hole 1 having different inner diameters and different lengths.
The bearing hole 16 is machined by the first cutting blade 33, and the seal holes 17, 18 are machined by the second and third cutting blades 34, 35. Therefore, the cutting blades 33, 34, 35 are arranged apart from each other in the axial direction of the tool body 23, and each of the cutting blades 33, 34, 35 is
The radii of the blade rotation circles are different from each other according to the inner diameters of the holes 16, 17, and 18.

In the case of the illustrated example, since the bearing hole 16 is most required to be machined with accuracy, the wear degree of the first cutting blade 33 is controlled based on the inner diameter measurement value of the bearing hole 16 after the machining, and the bearing hole 16 is controlled. When the inner diameter of 16 becomes smaller than the allowable value, the tool correction by the correction head 21 is performed.

As shown in FIGS. 1 and 4, among the plurality of cutting blades 33, 34, 35, the first cutting blade 33 having the maximum working length of the workpiece 15 is the eccentric direction of the correction head 21 ( It is arranged in the direction of arrow D). Further, the second cutting blade 34 and the third cutting blade 35, which have a relatively short working length, are arranged in the circumferential direction of the tool body 23 with respect to the first cutting blade 33 so as to be out of phase with each other by predetermined angles θ1 and θ2. There is. When determining the length of the holes 16, 17, 18 to be machined, the circumferential length of the inner surface may be taken into consideration in addition to the axial length of the holes 16, 17, 18.

As shown schematically in FIG. 4, since the first cutting blade 33 is arranged in the direction in which the correction head 21 is eccentric (direction of arrow D), the correction head 21 is Δ in the direction of arrow D.
When d is displaced, the radius R1 of the cutting edge rotation circle of the first cutting blade 33
Increases by Δd. On the other hand, the second cutting blade 34 is
Since the phase is displaced from the first cutting blade 33 by the angle θ1, when the correction head 21 is displaced by Δd in the direction of arrow D, the radius R2 of the cutting edge rotation circle of the second cutting blade 34 is approximately Δd cos θ1. Will increase.

On the other hand, since the third cutting blade 35 is arranged so as to be out of phase with the angle θ 2 with respect to the first cutting blade 33, when the correction head 21 is displaced by Δd in the direction of arrow D, the third cutting blade 35 is arranged. The radius of the edge rotation circle is approximately Δd
Increase by cos θ2.

Therefore, by appropriately setting the angles .theta.1 and .theta.2 according to the machining lengths L1 to L3 by the cutting blades 33 to 35, the second and the second when the correction head 21 is eccentric by .DELTA.d. It is possible to adjust the radius increment of the rotary cutting edge circle of the three cutting blades 34, 35 to an optimum value. That is, even if the correction head 21 is eccentric only in one direction, it is possible to displace the plurality of cutting blades 33 to 35 by an amount corresponding to the amount of wear of each of them, thereby achieving optimum blade tip position adjustment.

For example, the processing length L2 of the second cutting blade 34 is the first
When the processing length L1 of the cutting blade 33 is about half, that is, the second
If the wear of the cutting blade 34 is about half the wear of the first cutting blade 33 and θ1 is set to + 60 °, the radius of the tip rotation circle of the first cutting blade 33 when the correction head 21 is eccentric. The radius increase amount of the cutting edge rotation circle of the second cutting blade 34 is Δd cos 60 ° with respect to the increase amount Δd, which is about half of Δd. Therefore, the tip positions of the cutting blades 33, 34 can be optimally corrected according to the respective wear amounts of the first cutting blade 33 and the second cutting blade 34.

For the third cutting blade 35, the angle θ
By setting 2 to a value according to the machining length L3, when the correction head 21 is eccentric by Δd in the above direction, the radius of the tip rotation circle of the third cutting blade 35 can be adjusted to an appropriate value. it can. For example, when the processing length L3 of the third cutting blade 35 is about half the processing length L1 of the first cutting blade 33, θ2 is set to −
Set around 60 °.

The second cutting blade 34 and the third cutting blade 35 may be shifted in phase in the same direction with respect to the first cutting blade 33 by angles θ1 and θ2. Further, the number of cutting blades is not limited to three, and in short, the present invention can be similarly applied to any rotary tool for boring including a plurality of cutting blades.

[0024]

According to the present invention, when the cutting blade correction head is eccentric in one direction in accordance with the wear amount of the first cutting blade, the cutting blades other than the first cutting blade are also suitable for the wear amount. Since it can be displaced to the position, even if the wear amounts of the plurality of cutting blades are different from each other, each cutting blade can be adjusted to a preferable cutting edge position by the cutting blade correction head.

[Brief description of drawings]

FIG. 1 is a front view of a tip portion of a processing machine including a rotary cutting tool according to an embodiment of the present invention.

FIG. 2 is a side view of a part of the processing machine shown in FIG.

FIG. 3 is a perspective view of a part of the processing machine shown in FIG.

FIG. 4 is a diagram showing a relationship between an eccentric amount of a correction head of the processing machine shown in FIG. 1 and a blade edge position.

FIG. 5 is a side view showing a part of a conventional processing machine.

[Explanation of symbols]

 21 ... Cutting blade correction head 22 ... Rotating cutting tool 23 ... Tool body 33 ... First cutting blade 34 ... Second cutting blade 35 ... Third cutting blade 40 ... Base 41 ... Movable part

Claims (4)

[Claims] 1. A tool main body provided on a cutting blade correction head having a base attached to a rotary shaft of a machine tool and a movable part capable of being eccentric in a specific radial direction with respect to the base, and an axial direction on the tool main body. It has a plurality of cutting blades that are arranged at distant positions and have different distances from the tool rotation center to the cutting edge rotation circle, and cut the inner surfaces of a plurality of workpieces with different machining lengths by the plurality of cutting blades. Which is a tool for arranging a first cutting blade having a maximum machining length among the plurality of cutting blades in the eccentric direction of the movable portion of the cutting blade correction head, and cutting blades other than the first cutting blade are used for the first cutting. A rotary cutting tool for boring, which is arranged by displacing a predetermined angle in the circumferential direction of the tool body with respect to a blade. 2. The cutting tool according to claim 1, wherein the angle formed by the first cutting blade and the other cutting blades is set in the range of 0 ° to 90 ° according to the machining length. . 3. A second cutting blade is arranged with a phase shift of an angle .theta.1 in the circumferential direction of the tool body with respect to the first cutting blade, and a third cutting blade is arranged with respect to the first cutting blade. The phase is shifted by an angle θ2 in the circumferential direction of
The cutting tool according to claim 1, wherein the absolute values of 1 and θ 2 are about 60 °. 4. A tool main body provided on a cutting blade correction head having a base attached to a rotary shaft of a machine tool and a movable part capable of being eccentric in a specific radial direction with respect to the base, and an axial direction of the tool main body. It has a plurality of cutting blades that are arranged at distant positions and have different distances from the tool rotation center to the cutting edge rotation circle, and cut the inner surfaces of a plurality of workpieces with different machining lengths by the plurality of cutting blades. Which is a tool for arranging a first cutting blade having a maximum machining length among the plurality of cutting blades in the eccentric direction of the movable portion of the cutting blade correction head, and a second cutting blade with respect to the first cutting blade. 60 in the circumferential direction of the tool body
A rotary cutting tool for boring, characterized in that the third cutting blade is arranged with a phase shift of -60 ° in the circumferential direction of the tool body with respect to the first cutting blade.