GB2266676A

GB2266676A - Tool-holder with coolant groove

Info

Publication number: GB2266676A
Application number: GB9302580A
Authority: GB
Inventors: Masakazu Matsumoto
Original assignee: Nikken Kosakusho Works Ltd
Current assignee: Nikken Kosakusho Works Ltd
Priority date: 1992-04-20
Filing date: 1993-02-10
Publication date: 1993-11-10
Anticipated expiration: 2013-02-10
Also published as: GB2266676B; ITMI930082A1; JPH0585535U; KR0132025Y1; FR2690102A1; DE4307280A1; ITMI930082A0; FR2690102B1; GB9302580D0; KR940007321U; IT1263779B

Abstract

The tool holder (1) has a tip portion (2) and a mounting portion (3) integral with the tip portion. A tool holding bore (4) is formed along the centre of the holder (1) and clamping bolts (5) are screwed into the tip portion (2). An injection groove (6) for injecting a cooling fluid is formed in the inner wall of the holding bore which has an injection port (6a) in its tip open to the distal end face of the tip (2). A fluid passageway (7) is formed within the mounting portion (3) which connects to the groove (6) at one end and open at the other end to the base end face of the mounting portion (3). The holder is particularly useful for tools such as boring tools and drills. <IMAGE>

Description

2266676

SPECIFICATION TITLE OF THE INVENTION TOOL HOLDER

BACKGROUND OF THE INVENTION 5 1. Field of the Invention:

This invention relates to a tool holder for holding a tool such as a boring tool or drill. 2. Description of the Prior Art:

In a conventional tool holder for a tool of the kind mentioned above, the shank of the tool is detachably fitted into and held by a tool holding bore, and the portion at which the tool holder and tool are attached is detachably mounted on a member such as the tool rest of a machine tool. In general, the tool holder is used to perform cuttingsuch as the boring or drilling of a workpiece by the tool.

When machining such as boring or drilling is performed, a universal-type feed water hose nozzle is used and a cooling fluid such as a cutting fluid is externally supplied to the nozzle. The fluid is sprayed toward the hole being machined and the blade edge of the tool, thereby cooling the same.

In the cooling performed by the cooling fluid according to the prior art described above, the cooling operation cannot be performed efficiently unless the tip of the nozzle is brought close to the portion being machined and the blade edge of the tool. When cooling is carried out by bringing the tip of the nozzle close 2 - to a minute clearance between the machined portion and the blade edge of the tool, the nozzle is urged and deflected by the flow of the cooling fluid during machining so that the direction in which the cooling fluid is jetted from the nozzle is shifted. As a result, the cooling fluid is no longer supplied to the machined portion and blade edge of the tool sufficiently. If machining is performed an extended period of time as by an unattended machine, machining may be executed without supply of the cooling fluid. This can lead to increased wear of the blade edge of the tool and a deterioration in the quality of the machined article.

SUMMARY OF THE INVENTION

An object of the present invention is to provide a tool holder which solves the aforementioned problems encountered in the prior art.

Another object of the present invention is to provide a tool holder in which the portion of a workpiece being machined and the blade edge of the tool can be cooled efficiently and reliably by a cooling fluid such as a cutting fluid without any shift in the position at which the cutting fluid is supplied, even if machining is performed for an extended period of time, thereby making it possible to reduce wear of the tool blade edge and prevent the occurrence of defective articles.

According to the present invention, the foregoing objects are attained by providing a tool holder having a tool holding bore for detachably holding the shank of a tool fitted therein, and a mounting portion for being detachably mounted on a machine tool, characterized in that the hole of the holding bore is formed to have an axially extending groove for injecting a cooling fluid, an injection port provided at the tip of the injection groove is opened to the distal end face of the tool holder, a fluid passageway communicating with a source which supplies the cooling fluid is formed inside the mounting portion, and the base end of the groove is connected to the fluid passageway.

In operation, the shank of the tool such as a boring tool or drill is fitted into and held by the tool holding bore, the mounting portion is mounted on a member such as the tool rest of the machine tool, and the tool is rotated while being advanced, thereby subjecting a workpiece to machining such as boring or drilling. When machining is being performed, the cooling fluid such as a cutting fluid is fed under pressure from the cooling fluid supply source to the injection groove via the fluid passageway. The cooling fluid passes through a fluid passage, which is defined by the injection groove and the shank of the tool, and is injected along the axial direction from the end face of the tool holder. Thus, the machined portion of the workpiece and the blade edge of the tool are cooled by the injection of the cooling fluid from a position in close proximity to the machined portion and the blade edge.

By virtue of the axially extending groove formed in the wall of the holding bore of the tool holder, the cooling fluid strikes the machined portion of the workpiece and the blade edge of the tool by being injected from a proximate position without any deviation in the direction of injection. Since the machined portion and blade edge are thus cooled, reliable cooling can be performed with a small quantity of the fluid. Accordingly, even if the machining operation is carried out over a long period of time as by an unattended machine, the cooling fluid will not deviate from the machined portion and blade edge. As a result, the blade 1 5 edge is cooled sufficiently and does not readily sustain wear. In addition, faulty articles ascribable to machining by a worn blade edge are produced less frequently.

Other features and advantages of the present invention will be apparent from the following description taken in conjunction with the accompanying drawings, in which like reference characters designate the same or similar parts throughout the figures thereof.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 is a side view, a portion of which is shown in section, illustrating a first embodiment of a tool holder according to the present invention, wherein the tool holder is depicted in use; Fig. 2 is a transverse sectional view taken along line A-A of Fig. 1; Fig. 3 is a side view illustrating a second embodiment of a tool holder according to the present invention, wherein the tool holder is depicted with a drill bit mounted therein; and Fig. 4 is a transverse sectional view taken along line B-B of Fig. 3.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

Figs. 1 and 2 illustrate a first embodiment of a tool holder 1 according to the present invention. The tool holder 1 has a tip portion 2 of a comparatively small outer diameter, and a mounting portion 3 of a comparatively large outer diameter formed on the basend side of the tip portion 2. A step portion is defined where the tip portion 2 and mounting portion 3 meet. A tool holding bore 4 is formed along the center of the tool holder 1 extending from the tip portion 2 to a point a prescribed distance from the end of the mounting portion 3. A clamping bolt 5 is screwed into the tip portion 2 at each of two locations along the axial direction of the tool holder.

An injection groove 6 for injecting a cooling fluid such as a cutting fluid is formed in the inner wall of the holding bore 4 along the axial direction thereof at one location in the circumferential direction of the bore 4, as best seen in Fig. 2. The injection groove 6 has an injection port 6a provided in its tip. The injection port 6a opens to the distal end face of the tip portion 2 along with the distal end of the tool holding bore 4. A fluid passageway 7 is formed within the mounting portion 3 along the axial direction thereof. The fluid passageway 7 has its distal end connected to the base end of the injection groove 6, while the terminus of the passageway 7 is opened to the base end face of the mounting portion 3.

In this embodiment, a boring tool 8 having a straight shank 9 formed to include a flat portion 9a is used as the tool. The shank 9 is inserted into the tool holding bore 4 and the inner ends of the clamping bolts 5 are brought into pressing contact with the flat portion 9a to fixedly retain the shank 9 in the tool holder 1 in a detachable manner. The boring tool 8 has a cutting tip 10 secured to its distal end. The cutting tip 10 has a blade edge 10a arranged so as to be situated on an extension of the injection groove 6.

The tool holder 1 is detachably secured to a tool rest 11 of a machine tool by detachably fitting the mounting portion 3 in a mounting hole 12 provided in the tool rest 3 and holding fast a flattened recess 3a of the mounting portion 3 by the inner ends of a plurality of mounting bolts 13.

The tool rest 11 is formed to have a cooling fluid supply hole 14 connected to a source (not shown) which supplies the cooling fluid. The distal end of the supply hole 14 is connected to the terminus of the cooling fluid passageway 7 via a supply port 14a provided in the bottom of the mounting hole 12.

The boring tool 8 is secured to and held by the above-described tool holder 1, the tool holder 1 is mounted on the tool rest 11, and a workpiece 15 is subjected to boring work. In the machining operation, a valve (not shown) is opened at an appropriate time, and the cooling fluid such as a cutting fluid is fed under pressure from the cooling fluid supply source to the supply hole 14 by a pump or the like. The fluid is fed under pressure to the injection groove 6 through the fluid passageway 7 of the tool holder 1, the fluid flows through a fluid passageway formed by the groove 6 and the shank 9 of the boring tool 8, and the peripheral portion of a lower hole 15a of the workpiece 15 is cut by the blade edge 10a of the tool 8 while the cooling fluid is injected from the injection port 6a. along the outer peripheral surface of the boring tool 8.

When the boring work is performed, the boring tool 8 is advanced by the tool rest 11 while being rotated about its axis along with the tool holder 1, and the cooling fluid is injected from the injection port 6a of the injection groove 6 in a direction substantially parallel to the axial direction of the tool 8, as 8 illustrated by arrows A in Fig. 1. Since the injected cooling fluid is released toward the blade edge 10a of the tool 8 at a high pressure, the machine hole 15b of the workpiece 15 and the blade edge 10a are capable of being cooled owing to precise contact by the cooling fluid, which penetrates deep into the machined hole 15a, brought about by injecting the fluid from the distal end face of the tool holder 1 at a position in close proximity to the machined hole 15b and blade edge 10a.

Figs. 3 and 4 illustrate a second embodiment of the tool holder according to the present invention, in which portions identical with those in Figs. 1 and 2 are designated by like reference characters. This embodiment differs from the first embodiment in that the inner wall of the holding bore 4 is formed to have the cooling fluid injection groove 6 at three locations spaced apart equally by 120 in the circumferential direction, the clamping bolts 5 screwed into the tip portion 2 are arranged midway between the injection grooves 6 at one location in the circumferential direction, and a fluid passageway 17 connected to the base end of the injection groove 6 is made a hole having a circular transverse cross section.

In this embodiment, a drill 18 having a straight shank 19 formed to include a flat portion 19a is used as the tool. The shank 19 is inserted into the tool holding bore 4 and the inner ends of the clamping bolts 5 are brought into pressing contact with the flat 9 - portion 19a to fixedly retain the shank 19 in the tool holder 1 in a detachable manner.

When a workpiece (not shown) is being drilled by a blade edge 20 of the drill 18, a cooling fluid such as a cutting fluid is injected from all three of the injection grooves 6 in a direction substantially parallel to the axial direction of the drill 18, whereby the drilled portion of the workpiece and the blade edge of the drill 18 are cooled.

Though a cutting fluid is used as the cooling fluid in the first and second embodiments, a fluid such as high-pressure water or cooling air may be employed as the cooling fluid. Further, the tools used in this invention are not limited to a boring tool and drill.

The present invention is applicable to other types of tools as well.

Furthermore, the tool holder of the foregoing embodiments is described as having a tool holding bore into which the straight shank of the tool is fitted.

However, so long as the tool holder possesses a tool holding bore and a mounting portion mounted on the tool rest of a machine tool, the construction of the tool holder is not necessarily limited to that of the two above-mentioned embodiments. For example, the tool holder may have a tool holding bore for holding the tapered shank of a tool. Further, the number of injection grooves, the positions thereof and the transverse cross section can be modified at will.

As described above, a tool holder according to the present invention has an axially extending cooling fluid injection groove formed along the inner wall of a tool holding bore for detachably holding the shank of a tool fitted therein, an injection port provided at the tip of the groove is opened to the distal end face of the tool holder, a fluid passageway communicating with a source which supplies the cooling fluid is formed inside the mounting portion of the tool holder, and the base end of the injection groove is connected to the fluid passageway.

More specifically, the shank of the tool such as a boring tool or drill is fitted into and held by the tool holding bore, the mounting portion is mounted on a member such as the tool rest of a machine tool, and the tool is rotated while being advanced, thereby subjecting a workpiece to machining such as boring or drilling. when machining is being performed, the cooling fluid such as the cutting fluid is fed under pressure from the By virtue of the axially extending groove formed in the inner wall of the holding bore of the tool holder, the cooling fluid strikes the machined portion of the workpiece and the blade edge of the tool by being injected from a nearby position without any deviation in the direction of injection. since the machined portion and blade edge are thus cooled, reliable cooling can be performed with a small quantity of the fluid. Accordingly, even if the machining operation is carried out over a long period of time as by an unattended machine, the cooling fluid will not deviate from the machined portion and blade edge. As a result, the blade edge is cooled sufficiently and does not readily sustain wear. In addition, faulty articles ascribable to machining by a worn blade edge are produced less frequently.

As many apparently widely different embodiments of the present invention can be made without departing from the spirit and scope thereof, it is to be understood that the invention is not limited to the specific embodiments thereof except as defined in the appended claims.

Claims

WHAT IS CLAIMED IS:

1. A tool holder comprising:

a mounting portion for being detachably mounted on a machine tool; and a tip portion formed as an integral part of said mounting portion and having an end face; said mounting portion and said tip portion having a central, axially extending tool holding bore for detachably holding a shank of a tool fitted therein; said tool holding bore having an inner wall formed to include an axially extending groove for injecting a cooling fluid, said groove having a distal end, which is provided with an injection port that is opened to the end face of said tip portion, and a base end; said mounting portion being formed internally to have a fluid passageway communicating with a source which supplies the cooling fluid, the base end of said groove being connected to said fluid passageway.

2. The tool holder according to claim 1, further comprising clamping screws screwed into an outer peripheral side portion of said tool holding bore for clamping the shank of the tool.

3. The tool holder according to claim 1 or 2, wherein said mounting portion is clamped by mounting bolts screwed into the machine tool.

4. The tool holder according to claim 1, 2 or 3, wherein said tool holding bore is so adapted as to mate with and hold a straight shank of a tool.

5. The tool holder according to claim 1, 2, 3 or 4, wherein said tool holding bore is so adapted as to mate with and hold a tapered shank of a tool.

6. A tool holder substantially as herein described with reference to the diagrammatic drawings.