JP2003039221A - Hole processing method and boring tool - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable shortening of a honing machining time by making the field coarseness of a prepared hole effectively small through an easy process and easy composition. SOLUTION: A boring tool 10 is equipped with a body of a tool which can adjustably rotate, and polygon-like tips 14a-14c which function as preceding edges detachably attached on the body of a tool 12, and a round-shaped grinding chip 16 which function as a trailing cutting edge.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a boring method and a boring tool for boring a workpiece through a rotatable boring tool and then honing the boring hole of the workpiece.

[0002]

2. Description of the Related Art For example, a cylinder block constituting an internal combustion engine is provided with a plurality of cylinder bores. Normally, when drilling holes in this type of cylinder bore, it is necessary to carry out honing to the processed pilot holes after boring (boring).

Therefore, for example, Japanese Patent Laid-Open No. 9-254011.
As disclosed in Japanese Patent Publication, a boring means provided with a rotatable machining tool to which a blade is attached and provided with the machining tool so as to be movable back and forth in the axial direction, and a boring means formed on a workpiece. In the hole forming device having a honing means for honing the prepared hole, the boring means preliminarily partially cuts a portion of the inner peripheral surface of the prepared hole where the honing processing efficiency is poor. There is known a hole forming device that performs an auxiliary process for advancing the honing process, and the honing process means performs a honing process on the pilot hole subjected to the auxiliary process.

By the way, since the surface roughness of the prepared hole in the boring process which is a pre-process of the honing process has a great influence on the actual machining allowance by the honing process, the time required for the honing process is the time required for the boring process. It is almost affected by the surface roughness. In particular, since the honing process is a grinding process using a grindstone, if the machining allowance is large, the honing process may take a considerably long time.

Therefore, in order to improve the surface roughness of the prepared hole at the time of boring, there has been proposed a device in which a plurality of chips are detachably attached (for example, Japanese Patent Publication No. 1-17).
820).

Specifically, as shown in FIG. 7, the boring tool 1 is provided with a rotatable tool body 2, and a plurality of tool bodies 2 are provided at the tip end side of the tool body 2 at predetermined angular intervals. Chips, for example, four removable chips (throw-away chips) 3a to 3d are mounted. Then, by rotating the tool body 2 in the work 4, the chips 3a to 3d perform cutting work on the inner peripheral surface 4a of the work 4, and the work 4 is subjected to boring.

[0007]

By the way, in the boring tool 1 described above, if the relative positions (balances) of the four chips 3a to 3d are set accurately, the prepared hole of the work 4 is formed. It is possible to maintain good surface roughness.
However, in practice, it is extremely difficult to accurately set the relative positions of the chips 3a to 3d, and the work 4
The surface roughness of the pilot hole becomes large.

That is, the boring processing state of the work 4 by the chips 3a to 3d is schematically shown in FIGS. 8 and 9, which is ideal when the chips 3a to 3d are accurately arranged at desired positions. During the rough hole processing, the surface roughness of the rough hole becomes small and the machining allowance H is reduced (see FIG. 8). on the other hand,
As shown in FIG. 9, when the relative positions of the chips 3a to 3d are deviated from each other, the cutting positions of the chips 3a to 3d into the work 4 are different from each other. As a result, the surface roughness after the boring process by the boring tool 1 becomes large, and in practice, the machining allowance H1 in the honing process is increased.
However, it is pointed out that there is a problem that the stock removal H is considerably increased in comparison with the ideal stock removal H after machining.

The present invention solves this kind of problem, and the surface roughness of the prepared hole after boring can be effectively reduced by a simple process and structure, and the honing processing time can be shortened. An object of the present invention is to provide a hole drilling method and a boring tool capable of improving the efficiency of the entire hole drilling.

[0010]

In the hole drilling method according to the present invention, in the boring step of performing the down hole drilling on the work prior to the honing step, a removable polygonal chip for cutting is used as a leading edge on the work. In addition to drilling, the work is drilled using a removable round-shaped cutting tip as a trailing blade.

Therefore, the workpiece is first subjected to a cutting treatment with a polygonal tip for cutting, and after removing most of the machining allowance, the circular tip for cutting smoothes the pilot hole of the workpiece. A cutting process can be performed to remove the machining allowance remaining in the prepared hole. As a result, it is possible to effectively reduce the surface roughness of the pilot hole of the work after the boring process, and the subsequent honing process can be performed reliably in a short time, improving the efficiency of the entire hole drilling process. Can be easily achieved.

Further, in the boring tool according to the present invention, the cutting polygonal tip functioning as the leading blade and the cutting round tip functioning as the trailing blade can be detachably attached to the rotatable tool body. Has been done. Therefore, with a simple structure, while performing the pre-drilling of the work with high accuracy, if the mounting angle of the cutting circular tip is sequentially changed, the entire outer peripheral portion of the cutting circular tip becomes the cut portion. It can be used many times and is economical.

Further, the position of the cut portion of the cutting round-shaped insert is located behind the cutting portion of the cutting polygon-shaped insert in the machining direction of the tool main body and outside in the radial direction of the tool main body. It is set to be separated by a predetermined distance. As a result, the pre-drilling with the round cutting tip following the cutting polygonal tip is performed satisfactorily and continuously, and it is possible to effectively reduce the surface roughness of the pilot hole and simplify the structure. Can be realized.

[0014]

1 is a perspective view of a main part of a boring tool 10 for carrying out a hole drilling method according to a first embodiment of the present invention, and FIG. 2 is the boring tool. It is a principal part side view of 10.

The boring tool 10 is connected to a spindle (not shown) and is rotatable, and is detachable from the tool body 12. The cutting tool is a polygonal tip for cutting, which serves as a leading blade for preparing a hole in a workpiece W. 14a to 14c and the polygonal tip 1 which can be attached to and detached from the tool body 12.
As a subsequent blade of 4a to 14c, there is provided a cutting round tip 16 for performing a pilot hole machining on the work W.

The polygonal chips 14a to 14c are formed, for example, in a rectangular shape, and cut portions 18 are provided at the four corners, respectively, and the arbitrary cut portions 18 are set at positions for preparing holes. The round chip 16 can have the cut portion 20 set at an arbitrary portion of the outer peripheral portion.

At the tip of the tool body 12 in the machining direction (direction of arrow A), first to fourth tip mounting portions 22a to 22d are provided at intervals of 90 °, for example. First
The polygonal chips 14a to 14c and the circular chip 16 are removably attached to the fourth chip attachment portions 22a to 22d via the fixtures 24, respectively, and the polygonal chips 14a to 14c and the circular chip 16 are attached. The shaped chip 16 means the first to fourth chip mounting portions 22.
The position can be adjusted in the radial direction (direction of arrow C) of the tool body 12 via a to 22d.

As shown in FIG. 2, the position of the cut portion 20 of the round chip 16 is such that the polygonal chips 14a to 14a.
With respect to the position of each cut portion 18 of c, the tool body 12
It is separated by a distance T to the rear of the machining direction (direction of arrow B).
The diameter D1 of the virtual circle that is in contact with the cut portion 20 about the axis of the tool body 12 is set to satisfy the relationship of D1> D2 with respect to the diameter D2 of the virtual circle that is in contact with the cut portion 18. That is, the position of the cut portion 20 of the round tip 16 is a predetermined distance (D1-) in the radial direction outward (direction of arrow C) of the tool body 12 with respect to the position of each cut portion 18 of the polygonal tips 14a to 14c. It is set to be separated by D2) / 2.

The operation of the boring tool 10 thus constructed will be described below in connection with the hole drilling method according to the first embodiment.

As shown in FIG. 3, the work W has been subjected to rough boring on the inner surface 30 in a previous step in advance, and the inner surface 30 is boring using the boring tool 10. . The boring tool 10 is connected to a spindle (not shown) and moves in the direction of arrow A while rotating.

Polygonal tips 14a to 14c and a round tip 16 are detachably attached to the tip of the tool body 2, and the polygonal tips 14a to 14c are attached.
Each of the cutout portions 18 of the above-mentioned protrudes from the cutout portion 20 of the round tip 16 by a distance T in the direction of the arrow A (see FIG. 2). Therefore, on the inner surface 30 of the work W,
First, the polygonal chips 14a to 14c serve as the leading blades to perform the pilot hole processing. Then, a round tip 1 as a trailing blade
6 has polygonal chips 14a to 1 on the inner surface 30 of the work W.
Pre-drilling is performed so as to remove the machining allowance remaining after cutting by 4c.

At this time, as shown in FIG. 4, when the relative positions of the polygonal chips 14a to 14c are not accurately set, the surface roughness of the work W after the pilot hole machining by the polygonal chips 14a to 14c is performed. Is large, and there is a relatively large stock removal H2.

However, in the first embodiment, the round-shaped chip 16 is used after the polygonal-shaped chips 14a to 14c and the round-shaped chip 16 is prepared.
The position of the cut portion 20 of 6 is the polygonal chip 1
4a to 14c are spaced apart from the positions of the respective cut portions 18 in the radial direction of the tool body 12 by a predetermined distance (see FIG. 2).
reference). As a result, the round chip 16 can remove the machining allowance H2 left behind by the polygonal chips 14a to 14c, and can effectively reduce the surface roughness due to the boring process.

As described above, after the boring process is completed,
Honing is applied to the work W. At the time of honing of the work W, as shown in FIG. 4, the machining allowance H3 after the preparation of the prepared hole by the round tip 16 may actually be removed by grinding. At this time, the machining allowance H3 is considerably reduced as compared with the machining allowance H2 remaining after the pilot hole machining of the polygonal chips 14a to 14c, and an effect that the time required for the honing machining is shortened at a stroke is obtained.

As described above, in the first embodiment, the workpiece W is subjected to the pilot hole machining using the polygonal chips 14a to 14c as the leading blades, and then the round chip 16 is used as the trailing blade on the workpiece W. By performing the pilot hole processing, the surface roughness of the pilot hole of the work W is effectively reduced. Therefore, the machining allowance H3 in the honing process for performing the grinding work can be reduced as much as possible, the honing processing time can be easily shortened, and the efficiency of the entire pilot hole processing operation can be reliably achieved. .

Further, the round chip 16 can be used as the cut portion 20 at any position on the outer peripheral portion thereof. Therefore, as compared with the polygonal chips 14a to 14c having the cut parts 18 at four locations, a considerably large number of cut parts 20 can be set, and the durability of the round chip 16 is effectively improved. This allows the boring tool 10 as a whole to be economically manufactured.

FIG. 5 is a perspective view for explaining a main part of a boring tool 40 according to a second embodiment of the present invention. The same components as those of the boring tool 10 according to the first embodiment are designated by the same reference numerals, and detailed description thereof will be omitted.

The boring tool 40 is provided with two polygonal tips 14a and 14b and two round tips 16a and 16b, and the positions of the cut portions 20 of the round tips 16a and 16b are the same as those of the polygon tip. Chip 14
With respect to the positions of the respective cut portions 18 of a and 14b, they are set behind the tool main body 12 in the machining direction and radially outward of the tool main body 12 so as to be separated from each other by a predetermined distance.

In the boring tool 40 configured as described above, as shown in FIG. 6, after the workpiece W is pre-drilled using the polygonal chips 14a and 14b as the leading blades, the circular chip is formed. The workpiece W is prepared with a pilot hole by using 16a and 16b as subsequent blades. Therefore, the machining allowance H4 remaining after the pilot hole processing by the polygonal chips 14a and 14b is performed.
However, since it is reliably removed by the round chips 16a and 16b, the surface roughness of the prepared hole of the work W is effectively reduced.

In particular, the two round chips 16a, 16b
By using, the surface roughness of the work W after the boring is further reduced, and the machining allowance H4 can be reduced as much as possible. As a result, in the second embodiment, the time required for the honing process can be shortened all at once, and the effect of performing an efficient and highly accurate hole drilling operation can be obtained.

In the first and second embodiments, the tool body 12 is provided with the first to fourth tip mounting portions 22a-2.
Although 2d is provided, five or more chip mounting portions may be provided and a desired number of polygonal chips and round chips may be mounted on these. Further, by mounting the honing processing means on the tool body 12 and performing the boring process and the honing process in the same process, it becomes possible to avoid the influence of a tool mounting error.

[0032]

According to the hole boring method and boring tool of the present invention, the boring process is performed on the work by using the cutting polygonal tip as the leading blade in the boring process for boring the work prior to the honing process. In addition to the above, the rounded tip for cutting is used as a subsequent blade to perform the pilot hole processing on the workpiece, whereby the surface roughness of the pilot hole can be effectively reduced. As a result, the stock removal in honing is reduced, the honing time can be effectively shortened, and the efficiency of the entire hole drilling operation can be easily achieved.

[Brief description of drawings]

FIG. 1 is a perspective view of a main part of a boring tool for carrying out a hole drilling method according to a first embodiment of the present invention.

FIG. 2 is a side view of a main part of the boring tool.

FIG. 3 is an operation explanatory diagram when a pre-drilling process is performed on a work by the boring tool.

FIG. 4 is a schematic diagram when performing a cutting operation with a polygonal tip and a round tip attached to the boring tool.

FIG. 5 is a perspective view of a main part of a boring tool according to a second embodiment of the present invention.

FIG. 6 is a schematic diagram when performing a pre-drilling process for a workpiece by using a polygonal tip and a round tip attached to the boring tool.

FIG. 7 is a configuration explanatory view of a boring tool according to a conventional technique.

FIG. 8 is a schematic diagram when performing ideal boring processing with the boring tool.

FIG. 9 is a schematic view when actually performing a pilot hole machining by the boring tool.

[Explanation of symbols]

10 ... Boring tool 12 ... Tool bodies 14a to 14c ... Polygonal tip 16, 16a, 16
b ... Round shaped chips 18, 20 ... Notched portions 22a-22d ... Tip mounting portion 30 ... Inner surface 40 ... Boring tool W ... Work

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Hitoshi Fukumitsu             1-10-1 Shinsayama, Sayama City, Saitama Prefecture             Engineering Co., Ltd. F-term (reference) 3C037 BB15                 3C046 AA08 AA11 KK02 MM01

Claims (3)

[Claims] 1. A boring step for boring a work through a rotatable boring tool, and a honing step for honing a boring hole of the work. The boring step comprises: Detachable polygonal tip is used as a leading blade to prepare a hole in the work,
A hole drilling method, which comprises using a removable circular tip for cutting as a trailing blade to perform a pilot hole drilling on the work. 2. A boring tool for performing a pilot hole machining on a workpiece before honing the pilot hole of the workpiece, which is a rotatable tool body, and is attachable to and detachable from the tool body, A cutting polygonal tip that performs pre-drilling on the work as a leading blade, and a round cutting tip that is removable from the tool body and that performs a pre-drilling on the work as a trailing blade of the cutting polygonal tip. A boring tool characterized by comprising: 3. The boring tool according to claim 2, wherein the position of the cutting portion of the cutting circular shaped tip is rearward in the processing direction of the tool body with respect to the position of the cutting portion of the cutting polygonal shaped tip. In addition, the boring tool is set so as to be separated from each other in the radial direction of the tool body by a predetermined distance.