JPH10296517A - Cutting tool and its holding device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance the durability of a sealing member to be disposed in the inside of a spindle for a machine tool. SOLUTION: This cutting tool comprises a cutting edge part and an axial part 103 provided, has at least the free end of the axial part 103 turned out to be a tapered surface 204, and also has a cutting lubricant passage 6 which is opened at the free end at one end, and also opened at the cutting edge part at the other end. When the cutting tool is inserted into the spindle of a machine tool so as to be fixed thereto, the tapered surface 204 abuts against a sealing member 31 in the inside of the spindle. When the sealing member 31 is brought into contact with the tapered surface 104, a large contact surface area can be secured. Therefore, pressure per unit area applied to the sealing member 31 can thereby be reduced, and the durability of the sealing member 31 can thereby be enhanced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a cutting tool having a cutting agent passage and a holding device therefor, for example, a drill and a drilling machine.

[0002]

2. Description of the Related Art A drill having a cutting agent passage penetrating in the axial direction has been provided in order to efficiently supply a cutting agent to a workpiece to be processed. In such a drill, the free end of the shaft portion has a cutting agent injection port, and the tip of the blade portion has a cutting agent leakage port. Conventionally, a shaft portion of a drill is inserted into a lower end of a main shaft of a machine tool and fixed by a chuck. The cutting agent passes through the main shaft of the machine tool and is supplied to a cutting agent inlet of the shaft portion of the drill. A sealing member is provided between the main shaft and the shaft portion so that the cutting agent does not leak.

[0003] The seal member has a through-hole whose opening end extends in a trumpet shape, is formed of an oil-resistant elastomer material, and is attached to the main shaft directly or via an adapter. The shaft of the drill is usually cylindrical, and the beveled edge of the free end of the drill abuts against the trumpet-shaped opening wall surface of the sealing member. This prevents the cutting agent from leaking.

[0004]

In the above-mentioned conventional construction, the edge of the free end of the shaft of the cutting tool comes into contact with the sealing member. Small contact area with Therefore, the pressure per unit area applied to the seal member increases, and a large load acts locally on the seal member. Therefore, the sealing member is greatly deteriorated, and its durability is impaired.

Further, when the diameter of the shaft changes when the drill is replaced, the contact portion of the seal member also changes. If the drill can be used for both small-diameter drills and large-diameter drills, a large-diameter seal member is required, making it difficult to make the apparatus compact.

[0006]

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and a cutting tool according to the present invention
A free end of the shaft portion is a tapered surface forming a sealing surface, and the shaft portion is open at one end at the free end and opens at the other end at the blade portion. Characterized by having a cutting agent passage that performs

In the cutting tool of the present invention, when the shaft is inserted into the main shaft of the machine tool, the tapered surface of the cutting tool comes into contact with a seal member in the main shaft. A large contact area can be secured in the contact between the seal member and the tapered surface. Therefore, the pressure per unit area applied to the seal member can be reduced, thereby improving the durability of the seal member.

In the cutting tool according to the present invention, a groove may be formed at the top of the free end of the shaft, and the cutting agent passage may be opened inside the groove.

In the cutting tool configured as described above, the cutting agent supplied from the main shaft of the machine tool concentrates in the groove at the top of the shaft, and the opening of the through hole formed inside the groove (cutting agent injection). To the inlet). The through-hole serves as a cutting agent passage, and the cutting agent is supplied to the object to be processed from the leak opening that opens to the blade portion.

The shape of the groove formed at the top of the shaft of the cutting tool is not particularly limited as long as it communicates with the cutting agent inlet. Although the cross section is substantially U-shaped in the embodiment,
For example, it may be a funnel-shaped groove communicating with each cutting agent inlet. In other words, it is preferable that the diameter of the cutting agent passage is enlarged at the cutting agent inlet so that the cutting agent is efficiently injected into the cutting agent passage. From the viewpoint of ensuring the sealing performance on the tapered surface, the groove needs to be abutted against the sealing member.

In the cutting tool, one or two or more through holes serving as cutting agent passages are formed. The opening position of the through hole in the groove is not particularly limited, but from the viewpoint of efficiently taking in the cutting agent, it is preferable that the opening position be the bottom wall of the groove. Further, the opening position of the blade portion of the through hole is not particularly limited, but it is a tip portion in a normal drill.

A holding device for a cutting tool according to the present invention is a holding device used for the cutting tool according to the present invention, and includes a tool fixing means for fixing the shaft portions of the cutting tools having different shaft diameters, and a front tool fixing. Ring-shaped sealing means with which the tapered surface of the cutting tool fixed to the means abuts, and a cutting agent supply passage opening in a range surrounded by the seal.

A well-known chuck such as a single-acting chuck, a universal chuck, a double-acting chuck, and a dual-purpose chuck can be used as a means for fixing the shaft portion. The sealing means abuts against the tapered surface to prevent the cutting agent supplied from the main shaft of the machine tool to the top of the shaft portion from leaking along the side surface of the shaft portion. This is a member for ensuring that the liquid is injected into the inlet. Therefore, the sealing means is preferably made of an oil-resistant elastomer such as nitrile rubber. The sealing means may be continuously abutted on the tapered surface of the shaft of the cutting tool in the circumferential direction. In the embodiment, a general-purpose O-ring is employed from the viewpoint of reducing the cost of parts. The cutting tool that can be used with a given O-ring has the outermost diameter of the tapered surface that is the same as the diameter of the O-ring and the smallest shaft diameter. Cutting tools with a shaft diameter range up to a large diameter can be used.

According to the holding device for a cutting tool configured as described above, the tapered surface of the shaft of the cutting tool comes into contact with the sealing member. Therefore, the pressure per unit area applied to the seal member does not increase so much, and the life of the seal member is prolonged.

Furthermore, if the sealing member is in contact with any of the tapered surfaces, a desired sealing property can be obtained, so that a high precision is not required for mounting the cutting tool. Therefore, attachment of the cutting tool to the machine tool becomes easy.

If the shape of the tapered surface of the cutting tool (inclination angle, length of the inclined surface, etc.) is standardized, even if the diameter of the shaft portion of the cutting tool changes, the sealing performance can be maintained without any replacement of the sealing member. , The shaft portions of the cutting tools having different diameters can be held. Note that what is described here as a cutting agent is not limited to cutting oil, water-soluble cutting agent, and the like, but also includes one that increases cutting efficiency by cooling with cooling water, cooling air, or the like.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below based on examples. FIG. 1 is an exploded view of a drill 1 and a holding device 10 of the embodiment. FIG. 2 shows a state where the drill 1 is held by the holding device 10.

The drill 1 of the embodiment comprises a blade 2 and a shaft 3. The blade portion 2 is formed with a spiral blade. Shaft 3
A tapered surface 4 which is continuous in the circumferential direction is formed on the periphery of the free end of the. A single groove 5 is formed on the top surface 8 of the free end of the shaft 3. Reference numeral 6 in the drawing denotes a cutting agent passage, which is formed in two straight lines in the drill of this embodiment. The cutting agent passage 6 may be formed in a spiral shape. The number of cutting agent passages 6 is not particularly limited. FIG. 3 is a plan view of the free end of the shaft portion 3. As shown in FIG.

The holding device 10 includes a chuck 11 and an adapter 2
0 and the main shaft 40. The chuck 11 is a general-purpose one. In this embodiment, a commercially available three-jaw drill chuck is used.

As shown in detail in FIG. 4, the adapter 20 has a first cylindrical portion 21 having a thread groove formed on the outer peripheral surface thereof, and a second cylindrical portion screwed to the first cylindrical portion 21. Consists of 25.
As shown in FIG. 5 showing the bottom surface of the adapter 20, the lower end inner surface of the first cylindrical portion 21 is formed in a hexagonal hole 23. The hexagonal hole 23 connects the first cylindrical portion 21 with the female screw portion 41 of the main shaft 40.
This is for inserting a hexagon wrench when screwing into the screw. The second cylindrical portion 25 has an undercut portion 27.
When the second tubular portion 25 is externally mounted on the first tubular portion 21, the first O-ring 31 is gripped by the undercut portion 27 and the lower end of the first tubular portion. A second O-ring 33 is provided on the upper side of the second cylindrical portion 25. The second O-ring 33 is a member for taking a seal between the adapter 20 and the main shaft 40.

As shown in FIG. 2, the adapter 20 is
0 is screwed into the female screw portion 41. A supply path 43 for the cutting agent is formed in the main shaft 40.

Returning to FIG. 4, the angle α of the tapered surface of the drill
Is defined, the tapered surface of the shaft portion always contacts the first O-ring 31 even if the diameter of the shaft portion changes. FIG. 4 shows a small-diameter shaft portion 103 represented by a solid line and a large-diameter shaft portion 203 represented by an alternate long and short dash line. That is, each shaft portion 103 and 2
When 03 is centered on the adapter 20, the tapered surfaces 104 and 204 come into contact with the first O-ring 31. Further, even if there is a slight misalignment, the desired sealing property is maintained as long as the first O-ring 31 contacts the tapered surfaces 104 and 204.

To ensure that the tapered surface abuts against the first O-ring 31, the diameter of the shaft must be larger than the inner diameter of the first O-ring 31. The angle α of the tapered surface is 4
5-135 degrees is preferred. More preferably, 60 to 12
0 degrees. In the embodiment, α = 90 degrees.

FIG. 2 shows a state in which the drill 1 is attached to the holding device 10. When the chuck 1 is released from this state, the drill 1 is removed and can be replaced. After removing the drill 1, the hexagonal bar wrench is inserted into the hexagonal hole 23 of the adapter 20 through the chuck 11 and rotated, whereby the adapter 20 can be easily replaced.

[0025]

As described above, the cutting tool according to the present invention includes the blade and the shaft, and the periphery of the free end of the shaft is formed in a tapered surface. In the cutting tool configured as described above, when the shaft portion is inserted into the main shaft of the machine tool, the tapered surface thereof comes into contact with a seal member in the main shaft. A large contact area can be secured in the contact between the seal member and the tapered surface.
Therefore, the pressure per unit area applied to the seal member can be reduced, thereby improving the durability of the seal member. Further, by standardizing the tapered surface, the contact between the sealing member and the tapered surface is maintained regardless of the diameter of the shaft portion.

The present invention is not at all limited to the description of the above-described embodiments and examples. Various modifications are included in the present invention without departing from the scope of the claims and within the scope of those skilled in the art.

[Brief description of the drawings]

FIG. 1 is an exploded view of a drill and a holding device according to an embodiment.

FIG. 2 is a partial sectional view showing an aspect of holding a drill by the holding device.

FIG. 3 is a plan view of a free end of a shaft of the drill according to the embodiment.

FIG. 4 is an enlarged sectional view of the adapter of the embodiment.

FIG. 5 is a bottom view of the adapter.

[Explanation of symbols]

1: Drill 2: Blade part 3: Shaft part 4: Taper surface 5: Groove 6: Cutting agent passage 7: Cutting agent inlet 8: Top surface 10: Holding device 11: Chuck 2
0: Adapter 31, 33: O-ring 40: Spindle

Claims (3)

[Claims] 1. A shank having a blade portion and a shaft portion, wherein at least a peripheral edge of a free end of the shaft portion is a tapered surface forming a sealing surface, and the shaft portion has one end opened at the free end and the other end formed with a free end. A cutting tool having a cutting agent passage opening to the blade portion. 2. The cutting tool according to claim 1, wherein a groove is formed at the top of the free end of the shaft, and the cutting agent passage opens inside the groove. 3. A cutting agent having a blade portion and a shaft portion, wherein at least a peripheral edge of a free end of the shaft portion has a tapered surface, and the shaft portion has one end opened at the free end and the other end opened at the blade portion. A holding device for holding a cutting tool having a passage, wherein a tool fixing means for fixing the shaft portion of the cutting tool, and a ring-like shape in which the tapered surface of the cutting tool fixed to the tool fixing means abuts. A cutting tool holding device, comprising: sealing means; and a cutting agent supply passage that opens in a range surrounded by the sealing means.