JP3102889B2 - Improved integrated boring and threading tool and method - Google Patents

Description

The present invention is a continuation-in-part of co-pending application Ser. No. 08 / 301,329, filed Sep. 6, 1994, filed on Sep. 6, 1994.

TECHNICAL FIELD The present invention relates to a cutting tool (boring tool) for boring and threading (cutting too).
With respect to l), more particularly the integrated tools and the various chamfers (bits, chamfers), counterbore (deep counterbore) and bores to be threaded with different shapes, sizes and properties using the tools. The present invention relates to a method of producing a hole having a desired tool without changing the tool.

Background Threaded holes and bores are most often made using multiple tools, and typically comprise the center of the next tool and a center or spot drill to create the first chamfer. , A drill for creating a core hole or bore, a counterbore forming tool, and a tap for threading the hole (threading tool). Special drills are known in which the first three tools are connected to create chamfers, counterbores and holes by incorporating multiple diameters into the grinding of the tools. However, the shape of such tools is complex and generally involves high manufacturing and regrind costs.
Since the diameters of the counterbore and the chamfer fit into the tool, they cannot be used extensively. Similarly, the relative length of the bore portion and the length of the hole created in the workpiece also depend on the length of the corresponding predetermined portion of the tool.

Conventionally, EP-A-0-334002 (Gaisler) equipped with a hole forming element and a screw mill along the shank.
sler)), a tool was provided.
Such a tool would first drill a bore hole, then, after reaching the desired hole depth, the tool may be laterally offset or laterally moved outward and then circular. It is moved to the path and simultaneously lifted to make a thread into the wall of the borehole. Once the thread is formed, the hole-forming element does not cut because the tool must be re-centered for withdrawal from the bore hole. Otherwise, the thread will be damaged. This sequence of steps involves the formation of a hole-forming element (eg, end cutting surface).
surface), chamfer forming surface, and counterbore forming surface)
Is logically required because it has a larger effective outer diameter than the thread milling part. In order to smooth the finishing pass or otherwise finish the thread, another tool must be inserted which is added to the tool cycle time. Furthermore, due to the relative size of the hole-forming element and the thread milling portion, these tools cannot create holes with portions that vary in shape, length, diameter or thread pitch.

Other tools having a thread mill fitted into the drill groove are known, and after drilling holes and chamfers, the thread can be milled with the same tool. However, these tools cannot create holes with varying lengths, diameters or thread pitches from one or more cross sections of the physical tool created. In addition, the chamfer forming portion of the tool is located on the back of the assembly and the hole is limited to a predetermined depth because the chamfer requires a full depth bore before the chamfer is formed. Is limited to a predetermined diameter.

Further, when excavating a ductile material, a continuous chip that is difficult to break is often formed. Such long chips can clump, entangle with other chips, and / or wrap around the tool, which can then create a "bird's nest" that is difficult to process. Accordingly, a need exists for an improved single boring and threading tool that can create holes of varying lengths, characteristics, and diameters that are identified as dimensional limitations of the tool and reduce chip handling problems. Get it.

SUMMARY OF THE INVENTION The object of the present invention is to address the problems described above, and the length, diameter,
An object of the present invention is to eliminate the disadvantages of using a single tool to create a hole whose shape and threading change.

It is another object of the present invention to provide a single tool that can selectively provide various bores, counter bores, and chamfers without the need for tool change.

Another object of the present invention is to provide a single rotating tool and method capable of creating and threading a hole having a counterbore and chamfer in a wide range of diameters, depths and shapes by simply changing the tool path. It is to provide.

Yet another object of the present invention is to provide a simple design for creating a threaded hole using a combination boring tool (tool), whereby the tool is easy to manufacture and manufacture. In addition, the re-grinding cost is reduced, and the combination machine can be operated without repeating the tool change.

A further object of the present invention is to eliminate the chip processing problems previously known in the industry.

It is yet another object of the present invention to provide a unitary tool that allows for selectively changing the order and relative size of the bore characteristics.

It is also an object of the present invention to provide a simple design for a combination boring tool used to make female or male threads of varying pitch.

It is a further object of the present invention to provide a single-piece rotary tool and method capable of creating and threading holes with chamfers of varying angles.

According to one aspect of the present invention, an improved boring and threading tool is provided, the tool having a shaft of a predetermined axial length and a proximal end and a distal end, wherein the distal end includes a hole forming element. I have it. The bore forming element is preferably a chamfer forming surface adjacent the distal end, a counterbore forming surface axially behind the chamfer forming surface, and a screw milling mill disposed between the counterbore forming surface and the proximal end. And
The chamfered surface is preferably convex in shape so that a chamfered portion with a variable angle can be formed. The screw milling machine preferably comprises one or more rows of axially aligned teeth. The counterbore forming surface has an effective outer diameter substantially greater than or equal to the effective outer diameter of the thread mill.

Other embodiments may have a counterbore forming surface that is slightly smaller (eg, 0.001 inch) than the effective outer diameter of the thread milling cutter.

The improved boring and threading tools can be used to produce a threaded or unthreaded bore in a workpiece, so that at least two hole portions having distinct diameters and depths are provided. is there. For example, the resulting threaded bore may have separate depth, center axis and diameter chamfers and counter bores without the need for tool change, as desired. The invention can be implemented on a numerically controlled machine, preferably with a three-axis control. A first bore portion having a selectively determined diameter and central axis is axially advanced into the workpiece using the drill bit, the bit is axially advanced into the workpiece, and the bit is selected by the numerically controlled machine tool. Created by advancing to a selectively determined first tool path having a first radius. If a non-circular bore is desired, the first toolpath may be modified appropriately to create such a bore.

The second bore portion may be created in the workpiece using a diameter and a central axis different from the diameter of the first bore portion. Similarly, the second bore portion uses the drill bit to feed the bit axially into the workpiece and selectively determines the bit with a second radius selectively adjusted using a numerically controlled machine tool. By creating the second tool path.

This process can be repeated as many times as desired to create a variable bore profile, effective inner diameter, depth, and an almost infinite combination of alignment and bore. Similarly, non-circular bores, such as lobe counter bores, can also be formed with or without axial feed of the tool with appropriate tool path modifications. The thread is created in the wall of any bore using a screw mill by moving the tool in a helical path selectively determined along the appropriate thread radius using a numerically controlled machine tool. obtain. A plurality of threaded threads (lead-in thread) can be created using a thread mill with every other tooth or teeth removed to form a respective number of threaded threads. . For example, if every other axial thread is removed, a threaded bore having two bite threads can be formed. If every third tooth is removed, a threaded bore with three bite threads can be formed.

In accordance with yet another aspect of the present invention, there is provided an improved boring and threading tool wherein the thread mill has at least one thread. If the screw mill has more than one tooth, all the teeth must be located at the same axial position of the screw mill so that a screw of varying pitch can be formed. This embodiment also has a hole forming element and may include a chamfer forming surface and a counterbore forming surface. The counterbore forming surface preferably has an effective outer diameter substantially smaller than the effective outer diameter of the thread mill. This embodiment is generally used in the same manner as described above, except that the bore with the thread is formed in one operation. For example, the bore portion to be threaded is generally formed by axially feeding a thread mill into the workpiece. This action provides both a bore and a series of rough threads in the bore portion. The reason is that the effective outer diameter of the screw milling cutter is larger than the effective outer diameter of the hole forming element, the chamfer forming surface and the counterbore forming surface. The thread is then finished by pulling the tool back from the bore that is threaded along the same path as the tool entered. Threads of varying pitch are formed by this tool by simply changing the feed rate of the tool.

External threads can also be formed using the tool of the present invention on a workpiece by feeding the tool along a helical rough threading path having a given threading outside diameter with respect to the center axis of the workpiece. The thread can be arbitrarily finished by pulling back the spiral, rough threading path. Similarly, pitch changing screws can be formed with this tool simply by changing the feed rate of the tool.

BRIEF DESCRIPTION OF THE DRAWINGS The present specification is completed by the claims particularly pointing out and distinctly claiming the invention, but will be better understood from the following description taken in conjunction with the accompanying drawings.

FIG. 1A is a cross-sectional side view of an improved boring and threading tool formed in accordance with the present invention.

FIG. 1B illustrates another embodiment of the improved boring and threading tool of the present invention, which is similar to that shown in FIG. 1A, but shows a modified concave hole forming element.

FIG. 1C illustrates yet another embodiment of the improved boring and threading tool of the present invention, illustrating a convex hole forming element.

FIG. 1D illustrates yet another embodiment of the improved tool of the present invention, illustrating the combination of a convexly curved biting surface and a counterbore forming surface.

FIG. 1E illustrates another embodiment of the present invention and illustrates a modified hole forming element.

FIG. 1F illustrates another embodiment of the improved tool of the present invention, wherein the bite forming surface is partially convexly curved.

FIG.1G shows yet another embodiment of the improved tool of the present invention, wherein the counterbore forming surface has an effective outer diameter smaller than the effective outer diameter of the screw milling, and the screw milling is located at the same axial position. With two threaded teeth.

FIG. 1H illustrates yet another embodiment of the improved tool of the present invention, wherein the teeth of the axial row of the screw milling cutter have been removed for every other bite threading.

2A-E are a series of schematic diagrams illustrating various processing steps of the improved tool of FIG. 1A forming a threaded bore.

FIG. 2F illustrates a schematic view of a screw to be formed using the improved tool of FIG. 1F.

FIG. 2G is a schematic diagram illustrating the simultaneous formation of a bite and a counterbore using the improved tool of FIG. 1F.

3A-J show schematic side views of an exemplary unthreaded bore formed by the tools and methods of the present invention.

FIG. 4A is a plan view of a typical tool path formed in the xy plane when the tool forms a bore having a diameter equal to the diameter of the drill bit.

FIG. 4B is a plan view illustrating a typical tool path formed in the xy plane when the tool forms a bore having a diameter greater than the diameter of the hole forming bit.

FIG. 4C is a plan view showing a typical tool path of a tool for forming a screw in a bore.

FIG. 4D is a plan view illustrating an exemplary non-circular tool path for a tool that forms a custom shaped bore.

DETAILED DESCRIPTION OF THE INVENTION Referring to the drawings in detail, where like numerals refer to like elements throughout, FIGS. 1A-H illustrate an exemplary preferred embodiment of the improved boring and threading tool 10 of the present invention. The following shows a schematic example. The tool 10 has a shaft 15 having a predetermined axial length having a proximal end (eg, 20) and a distal end (eg, 30). The proximal end 20 has a shank 40 for insertion into a clamping jaw or chuck of a boring device or other machine tool. Adjacent to and axially forward of the shank 40 and rearward of the distal end 30 is a thread milling portion 50, which comprises one or more axially aligned thread forming teeth. Has 60. But,
As shown with respect to the embodiment of FIGS. 2F and 2G, the tool of the present invention may be provided with a single tooth, which allows the formation of various screw pitches with a single tool. . In some tools formed according to the present invention,
The tool 10 does not have thread forming teeth on the thread milling portion 50. While this is less preferred, the bore is formed with or without threads, whether or not thread milling teeth are provided on the tool, with one or more teeth preferred for maximum compatibility. .

The hole forming element 70 is preferably located at the distal end 30 of the tool 10 adjacent to and axially forward of the screw milling cutter. The hole forming element 70 is preferably an end cutting surface 80 which preferably makes a center cut.
Having. All end cutting surfaces 80 are preferably provided with suitable chip gullets (not shown) for chip disposal, especially when milling or drilling small radius holes. Further, the hole forming element 70 has an end cutting surface 80.
A chamfer forming surface 100 adjacent to the end cutting surface in the axial direction and a counterbore forming surface 110 adjacent to the chamfer forming surface 100 and disposed in the axial direction of the chamfer forming surface. To form the desired chamfers and counterbore portions.

As will be appreciated, the substantially flat end cutting surface 80 of the tool of FIG. 1A maximizes the usable screw depth of the hole. Figure 1B
Has a concave end cutting surface 80, which is particularly useful when milling in a substantially helical tool path having a radius approximately corresponding to the outer diameter of the tool. In addition, the bending of the tool 10 is minimized. 1C-1F illustrate another embodiment of the tool 10, having a convex surface cutting surface 80 that provides excellent tip control when cutting ductile material. As will be appreciated, a convex surface may have a curved surface (eg, FIGS. 1D, F and H), a clearly angled surface (FIGS. 1C, E and G), or various surface configurations or combinations thereof. I can do it.

1A-H show a chamfer forming surface 100 of the tool 10 which is preferably located adjacent and axially rearward of the end cutting surface 80. FIG. 1D and 1F illustrate another embodiment of the tool 10, which has a chamfer forming surface 100 that is convexly curved to allow interpolation of chamfers at various angles. In particular, with such a structure,
Chamfers of various structures and sizes are provided, providing chamfer forming surfaces limited only by the path control capabilities of the machine. However, because the surface formed is somewhat scalloped, the axial feed rate per helical rotation of the embodiment of FIG. 1D is limited by the contour tolerance of the chamfered surface. FIG. 1E illustrates another embodiment of a tool 10 that includes an integrated chamfer forming surface (eg, 10 mm).
0) to provide the maximum possible feed rate, but this end cutting surface 80 may have a maximum hole depth, usable screw or chip formation problems. Is not appropriate due to poor specifications.

Thus, an advantage of the tool 10 is that the shape of the chamfer is not preset, as shown in FIGS. 1D and 1F. For example, a single or multiple chamfers may be formed having a single angle, multiple angles, or curved angles. Also, the chamfer may be formed in a distinct shape such as, for example, substantially circular, oval or trilobed. If the tool 10 is used to form a single chamfer angle, by resharpening the chamfer forming land 100 by a specific angle, the maximum axial direction per revolution along the tool path during the chamfer forming process Feeding becomes possible. If it is assumed that the tool will be used exclusively for a particular application (FIGS. 1A-C, E and G)
It is preferable to form a bit 70 having a predetermined chamfer forming angle (as exemplified in FIG. 3).

1A-H illustrate an improved cutting tool 10 of the present invention, which includes a counterbore forming surface 110 located adjacent and axially rearward of the chamfer forming surface 100. FIG.
Having. As will be appreciated, the counterbore forming surface 110
The axial length of (1) effectively limits the axial feed per helical revolution when forming a counterbore or hole using a tool. Counter bore forming surface 110
The undercut or relief formed in the bottom of the threaded bore finished during the threading process as described, since the axial length of (For example, the length u shown in FIG. 2E) also increases. Preferably,
The axial length M of the screw milling cutter (e.g., as illustrated in FIGS. 1A and B) is equal to or greater than the maximum usable screw depth desired for forming the bore. There must be. Preferably, the screw milling cutter 50 includes one or more teeth 60 arranged in an axial row. As best shown in FIG. 1G, in another embodiment, it is envisioned that teeth 60 along the axial row are removed to form a plurality of bite threads. Preferably, the diameter D of the shank 40 (as illustrated in FIG. 1C) is equal to or less than the diameter of the thread milling cutter 50 to minimize the overall material cost of the tool and maximize the suitability of the tool. Less than. However, if the depth of the counterbore is considered and the length to diameter ratio of the tool 10 is undesirable (due to strength and stiffness), the diameter D of the shank 40 is appropriately enlarged.
As best shown in FIG. 1A-1F, the tool 10 has an outer diameter d ₁ of the counterbore, which is larger or substantially equal than the outer diameter d ₂ of the thread milling.

Tool 10 illustrated in Figure 1G has a thread milling 50 and the counter bore forming surface 110, the surface has a smaller outer diameter d ₁ than the outer diameter d ₂ of the thread milling portion. This embodiment also includes at least one thread cutting tooth 60 and is exemplified as having two thread forming teeth located at the same axial position on the tool. If the screw mill has more than one tooth, all teeth must be arranged at the same axial position on the screw mill so that a screw of varying pitch can be formed. Another embodiment, not illustrated in the drawings, comprises a thread milling machine having at least two thread cutting teeth, the first tooth being adjacent to the counterbore forming surface and the second tooth being axially posterior to the first tooth. It is in. If the profile of the first tooth is rather small (about 0.05 inches), the pitch can vary by half of the small size (e.g., a 0.05 inch size allows for a pitch deviation of 0.025 threads).
The thread mill can then be fed axially into the workpiece in a spiral pattern to form threads along the desired portion of the bore wall. Although the use of this embodiment for threading the bore is time consuming, the angle of the threads (eg, 60 °) is the same, so that one tool forms a separate pitch. Thus, different pitches can be formed with the same tool using this alternative embodiment simply by changing the axial feed rate.

While the tool 10 of the present invention is used to form all types of bores (i.e., through bores, blind holes, etc.), FIGS. 2A-F illustrate machining with a tool 10 as illustrated and described with respect to FIG. 1A. FIG. 5 illustrates the steps used to form an exemplary blind bore or hole having a chamfer, counterbore, and threaded bore in an object. Suitable means for controlling the operation of tool 10 can be selected by those skilled in the art, but preferably a three-axis numerical control machine (not shown) is used. The numerical control machine is programmed to have some predetermined tool paths and operating programs stored in the controller, or human control is used to input quality control data before or during the machining operation. . Suitable controls are determined and used by those skilled in the art and include human hand-operated operation of the boring device held by hand. Further, the tool 10 is used on a quick change machine tool selected by a person skilled in the art. Such quick change machine tools allow for multitasking boring operations as part of a larger machining operation. Substantial cost savings are a result of the multitasking capabilities of the tool 10 since little tool change is required during operation.

As shown in FIG. 2A, for example, the first bore portion or chamfer 120 is formed by the chamfer forming land 100, rotating the tool 10 about the longitudinal axis L and centering on the chamfer center line C. It is formed by feeding in the axial direction toward the tool to the workpiece along a path having a radius r _1. The depth and diameter of the chamfer 120 can be selectively controlled by control means. As shown in Figure 2B, the counter bore 130 is formed by feeding in the axial direction along the counter bore forming the lands 110 on the path, the path to the radius r ₁ which is used to form the chamfered portion 120 It has a different radius r _2. The depth of the counterbore 130 is selectively determined and is preferably controlled by a numerical control machine.

As will be readily understood by those skilled in the art, non-circular bores and chamfers are also formed by utilizing the tool 10 to move the tool into a non-circular tool path perpendicular to the axis of the tool. Non-circular bores of various depths are formed by axially indexing the tool into the workpiece.
For example, the method may be used to form an elliptical bore, a trilobe bore, or a keyed bore. An exemplary non-circular tool path utilized to form a trilobe or counter bore is illustrated in FIG. 4D. In addition,
At least one non-coaxial bore is formed by the tool 10, as shown in 3J.

As shown in FIG. 2C, a bore 140 is formed by axially feeding the tool 10 using the same tool 10 to a desired depth of the tool path, where the tool path is chamfered.
120 and the radius of the tool path that are used to form a counterbore 130 (e.g., r ₁ and r ₂₎ having different radii r ₃ and. If the radius r ₃ is the same as r ₂ , the counterbore 130 and the bore 140 will obviously have the same diameter. As illustrated in FIG.2D, at least a portion of the bore 140 includes the tool 10 in the bore 1
The same tool 10 is threaded by threading from 40 to about 1.5 times the desired thread pitch (threaded bore 150). The desired spiral path and radius of the tool path (r
₄ ) is the desired screw (eg, longitudinal length, pitch,
Depth, etc.) selected to form a 50 mm thread mill
Is fed into the helical path of the bore 140 by at least one revolution of the tool 10 about the axis L and preferably by about 1 to 1.5 revolutions. FIG. 2E shows the completed threaded bore formed in the manner described by the unitary tool 10. If more than one bite (or start-in) thread is desired, the tool 10 is indexed about the central axis of the bore and the bite is indexed equally to the inner diameter of the bore. . For example, if two bite threads are desired, the tool 10 would be indexed 180 ° with respect to the central axis of the bore portion and the helical thread forming step described above would be repeated once, thus resulting in two bite threads. A threaded section is formed. Or,
The embodiment of the tool 10 illustrated in FIG.1G, as described herein, requires at least two bite threads without having to index the tool 10 each time an additional bite thread is desired. (Not shown) is replaced by being formed in a single screw milling operation. As will be appreciated by those skilled in the art, the tool 10 will thus form a plurality of biting threads, whether having a single thread forming tooth or multiple thread forming teeth. Can be used for Note that the exact order of the processing steps may vary somewhat. For example, the order in which the bore 140, counterbore 130, and bite 120 are formed may be reconfigured as desired.

As best illustrated in FIGS. 2F-G, the preferred embodiment of tool 10 as illustrated in FIG. 1G is also used to form threads in the bore. The bore 140 and the finishing thread 150 are formed by spirally feeding the tool 10 into the toolpath to a desired depth, the toolpath being used to form the chamfer 120 and the counterbore 130. Radius r ₃ different from the radius (eg, r ₁ and r ₂ )
Having. Since the largest effective outer diameter (eg, d ₁ ) of the counterbore forming surface 110 is smaller than the largest effective outer diameter (eg, d ₂ ) of the screw milling cutter 50, the counterbore 130
Is limited by the height h of the counterbore forming surface 110. Because the teeth 60 are larger in diameter than the hole-forming elements 70,
The operation of spirally feeding the tool 10 of FIG. 1G simultaneously mills both the bore and the rough thread of the finishing thread 150. By withdrawing the tool 10 along the same path as the feed path, the teeth 60 provide a “finishing pass” for forming the finishing thread 150.

The chamfer 120 and the counterbore 130 are formed alone or simultaneously before or after milling the bore 140. Figure
2G uses the tool 10 to make a chamfer 120 and a counterbore 130
Are formed at the same time. Chamfer 120 and counterbore 130 are circular or non-circular, and are limited only by the tool path in which these bores are formed. Tool 10
This embodiment of the combined screw and bore milling method uses a stud or boss by moving the tool 10 helically about the axis of the workpiece to form a screw of the desired pitch and outer diameter. Used to form threads in a workpiece such as (not shown). Alternatively, the helical feed speed of the tool 10 is synchronized with the pitch of the screw, and the tool 10 has a length of about 1.
When fed axially by a factor of 5, the embodiment of the tool 10 as illustrated in FIGS. 1A to 1H can also be used to form a screw in a workpiece.

The examples of FIGS. 3A-3J are intended as examples of substantially non-limiting variations of the order and combination of bore features implemented below. Another major advantage of the tool of the present invention includes a hole forming element 70 on the front of the thread milling structure 50,
The arrangement of the chamfer forming surface 100 is adjacent to this element. With this configuration, the tool 10 can be used to form a multi-function bore without changing the tool, with a bore having sufficient depth to access the conventional base mounted chamfer forming structure. Without chamfers different sizes and shapes are provided. In a preferred embodiment, the front end cutting face 80, the chamfer forming face 10
0 and counter bore forming surface 110 (for example, see FIGS. 1A-1H)
The combination provides substantially unlimited compatibility and applicability to the tools and methods of the present invention.

3A-J merely illustrate various exemplary blind holes formed in a single tool 10 using the method of the present invention. Each bore need not have all three features: a chamfer, a counterbore, and a threaded bore, and the order of placement of such features can vary without having to change tools. Similarly, each feature can occur multiple times in the same bore. Thus, many combinations can be created depending on the application for which the bore is required. As will be appreciated, the undercut end u of the bore does not appear symmetric. this is,
According to a preferred embodiment threading method in which the thread mill rotates in a helical path in about 1.5 revolutions.

FIG. 3A discloses a threaded bore 140 having a chamfer 120a, a counterbore 130, a bite chamfer 120b, and a threaded bore 140. FIG. This combination is shown in Figure 2A
-2E as described above. FIG. 3B shows a counterbore 130 followed by a biting chamfer 120B and a threaded bore 140. FIG. FIG.3C shows the chamfered portion 120.
a, illustrates a threaded bore 140 having a counterbore 130 and a chamfered chamfer 120b, and a threaded bore 140
The effective outer diameter b of the other bore (for example, the counter bore)
130) It is slightly smaller than the outer diameter B. FIG.3D shows the chamfer 120
a, shows a large diameter threaded bore 140 having a counterbore 130 and a chamfer 120b. FIG.3F discloses a threaded bore 140 having a chamfer 120a, a counterbore 130, and a biting chamfer 120b, wherein the axial length N of the counterbore is greater than that shown in the previous example. Long. FIG.3G shows an unthreaded bore 140 having a chamfer 120a, a counterbore 130 and a biting chamfer 120b.
Where the diameter B of the counterbore is larger than the diameter b of the bore. Since no screw is desired in this bore, there is no undercut as in the example of FIG. 2E described above.
FIG. 3H shows a threaded bore 140 having a first chamfer 120a, a second chamfer 120c, a counterbore 130 and a bite or third chamfer 120b.

FIG. 3J shows a counterbore 130 having a selectively determined centerline or centerline C of the bore, which is slightly offset from another centerline or centerline P of the threaded portion 140 of the bore. I have. This example illustrates another advantage of the unitary combination tool 10, which is that the bore portion, and in particular the tool path for forming the counterbore 130, is not custom-made non-circular (ie, oval) that is not coaxial with each other. Or trilobes) to form a bore. For example, in some applications, such as aircraft components, it is essential to provide custom bores and holes for stress control or component alignment. The substantially free-form on-the-fly control that can be implemented with the unitary tool 10 of the present invention creates eccentricities and offsets for any of the bore features described herein. FIG. 3J illustrates such an offset or eccentric counterbore 130.

It will be appreciated that the tool path required to form a particular bore feature will vary depending on the bore portion being formed. For example, FIG. 4A shows a plan view of the tool path 160 formed by the tool 10 when forming a hole having a diameter greater than the diameter of the tool 10. In effect, the tool 10 is rotated about a central axis L and fed helically into the workpiece. FIG. 4B shows a radius larger than the radius of the tool 10 (eg,
FIG. 4 is a plan view of a conical tool path 160 formed by the tool 10 when forming a hole having r ₁ ). For example, FIG.
A tool having a convexly curved biting surface fed along the tool path illustrated in B, the axial feed rate of the tool 10 changes continuously during the axial feed, while the fixed involute In order to maintain the rate of change, a bite with a convex or concave radius is formed. If both the axial cut rate and the involute change rate are fixed, a conical surface with a constant bite angle is formed. Alternatively, the second constant biting angle is formed adjacent to the first biting angle by changing either the axial feeding rate or the involute change rate during the axial feeding. An almost endless combination of bite angles and shapes are formed adjacent one or more bore portions. Figure
4C shows a top view of the helical tool path 160 of the tool 10 when the tool 10 forms a thread in a hole. The tool 10 rotates about a longitudinal axis L, is fed into the workpiece, and moves radially outward to form a screw, thereby creating a spiral tool path of increasing diameter. FIG. 4D shows a toolpath that is not circular but has one or more planes to provide a trilobe bore. Such a tool path is implemented with or without axial feed.

Tool 10 may be formed from many suitable materials depending on the type of application that tool 10 performs. Typically,
Most preferred materials include carbide and high speed steel. Further, the performance of tools formed in accordance with the present invention is enhanced by various external coatings, such as titanium carbide, titanium nitride, titanium carbonitride, titanium aluminum nitride, diamond or cubic silicon nitride, depending on the application. In addition, overheating of the tool 10 is reduced by passing coolant through a coolant opening of the tool (not shown), as is known in the art. Similarly, as is known in the art, tip removal is facilitated by applying an appropriate flue and / or cutting / cooling fluid to the bore during the molding operation.

By showing and describing preferred embodiments of the present invention, further adaptations of the drilling tools and methods shown and described herein are within the skill of the art without departing from the scope thereof. It can be achieved by appropriate modifications by the person. Some of these modifications have already been mentioned,
Others are known to those skilled in the art. Therefore, it is understood that the scope herein is to be defined by the following claims, and is not limited to the details of construction and operation shown and described in the specification and drawings.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-3-184722 (JP, A) JP-A-3-55106 (JP, A) JP-A-57-166629 (JP, U) (58) Field (Int.Cl. ⁷ , DB name) B23G 5/06 B23C 5/02

Claims (2)

(57) [Claims] A shaft having a proximal end and a distal end having a predetermined axial length, and a shank disposed adjacent the proximal end, wherein a screw is selectively formed in the workpiece to form a bore. An improved integrated rotatable tool for cutting, comprising an end cutting surface disposed adjacent said distal end, a chamfer forming surface adjacent said end cutting surface, and an axis of said chamfer forming surface. In a tool combining a counter bore forming surface disposed in the rear direction and a screw milling portion disposed between the counter bore forming surface and the shank, a tool having a combination of the screw milling portion and the counter bore forming surface is provided. An integrated rotatable tool, each having a predetermined effective outer diameter, wherein an effective outer diameter of the counterbore forming surface is smaller than the effective outer diameter of the screw milling portion. 2. The integrated rotatable tool according to claim 1, wherein said thread milling portion includes at least one thread cutting tooth or a plurality of axially spaced thread cutting teeth.