JP3009999B2 - Tool holder for cutting tools - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tool holder for holding a tool by a split collet, and more particularly to a structure capable of supplying a cutting fluid to a tool through the inside of the holder.

[0002]

2. Description of the Related Art When performing end milling, drilling, boring, or the like, it is necessary to supply a cutting fluid to a cutting position of a tool to perform lubrication, cooling, and chip removal.

In a conventional milling machine, an oil supply device is provided outside a main spindle on which a tool holder is mounted, and a cutting fluid is supplied to a cutting position from outside the main spindle. The apparatus manually adjusts the supply direction of the cutting fluid, and there is a problem that it is extremely difficult to appropriately adjust the supply direction according to various tools having different lengths and the like. In particular, when the number of tools is large, it is practically impossible to accurately adjust the lubrication direction to the cutting position.

On the other hand, as shown in FIG. 3, a collet chuck 32 is inserted into a holder shank 31 from the rear end face of the shank as a tool holder capable of supplying a cutting fluid through the spindle and the inside of the holder shank. A liquid supply hole 34 penetrating to the tapered hole 33 is provided, and the cutting fluid sent to the back of the tool 35 through the liquid supply hole 34 is supplied to a cutting position through a through hole 36 formed inside the tool 35. There is something.

However, in the tool holder having the above structure, the cutting fluid is supplied through the through hole 36 inside the tool 35, so that the cutting fluid cannot be supplied by a tool having no through hole without the through hole. In such a tool, the performance of the tool could not be sufficiently exhibited.

However, in practice, a tool without a hole is more common, there are many types, and the ability of the tool without a hole cannot be sufficiently exhibited is a major factor in achieving optimal tooling and the like. It is an obstacle.

Therefore, the present invention solves the above-mentioned problems, enables a tool without a hole to sufficiently exhibit its ability, and can reliably supply a cutting fluid to a cutting position through the inside of a holder. It is intended to provide a tool holder.

[0008]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a cutting method in which an inner peripheral surface of a tip portion of a holder shank is cut.
A tapered hole into which a split collet for cutting tool gripping is inserted is provided.Inside the holder shank, a cutting fluid supply hole is provided that penetrates from the tapered hole to the rear end surface of the shank. A fastener for pressing the split collet toward the inner side of the tapered hole by pushing the screw is attached to the provided screw portion, and the fastener is formed in a size to cover from the screw portion to the tip end surface of the split collet. ,
The tool has a structure in which a tool insertion hole having a diameter larger than the inner diameter hole of the split collet is provided at the tip of the fastener.

The above-mentioned tightening device comprises an outer ring engaged with the threaded portion of the holder shank, an inner ring rotatably held inside the outer ring and fitted to the tip of the split collet. The inner ring and a seal ring incorporated between the end face of the holder shank can be formed to have a structure in which a tool insertion hole is provided at the end of the inner ring.

[0010]

In the above construction, the tool is inserted into the inner diameter hole of the split collet from the tool insertion hole of the fastener, and the tool is held by reducing the diameter of the split collet by the fastener.

In this state, when the cutting fluid is supplied to the liquid supply hole of the holder shank, the cutting fluid is sent to the fastener through the split portion of the split collet. In this case, the tool insertion hole provided in the fastener is provided. Since the gap is larger than the inner diameter hole of the split collet and a gap is formed between the insertion hole and the tool, the cutting fluid is sent to the tip of the tool through the gap.

[0012]

1 and 2 show a tool holder according to an embodiment.

This tool holder is provided with a collet tightening tool 2 on an outer peripheral surface of a tip end of a holder shank 1 on which a tool 3 is mounted.
At the rear end of the holder shank 1, a pull stud bolt 4 for pulling a tool holder into a main shaft of a milling machine is mounted.

A tapered hole 5 is formed in the inner peripheral surface of the tip portion of the holder shank 1, and a split collet 6 for holding the tool 3 is accommodated in the tapered hole 5.

A liquid supply hole 7 penetrating from the tapered hole 5 to the rear end of the holder shank is formed inside the holder shank 1, and a pull stud bolt 4 is provided at the rear end of the liquid supply hole 7. A thread 9 to be attached is formed.

The split collet 6 has a tapered surface 9 on the outer diameter surface along the tapered hole 5 of the holder shank 1 and a tapered tip portion 10 inclined in a direction opposite to the tapered surface 9. An inner diameter hole 11 which is a straight circular hole for inserting the tool 3 is formed.

As shown in FIG. 2, a plurality of slit grooves 12 and 13 extending in the axial direction are formed on the peripheral surface of the split collet 6 to facilitate deformation of the collet. The slit groove 12 penetrates from the front end face to the rear end face of the collet 6. This slit groove 12
Is a passage through which the cutting fluid flows as described later.

On the other hand, as shown in FIGS. 1 and 2, the fastener 2 comprises an outer ring 14, an inner ring 15, and a seal ring 16, and the inner peripheral surface of the outer ring 14 A screw thread 18 which engages a screw portion 17 provided on the outer peripheral surface of the distal end portion, and a circumferential groove 1 into which the seal ring 16 is fitted.
9 are formed.

The inner ring 15 is rotatably mounted on the distal end of the outer ring 14 via a plurality of balls 20, and fits on the inner peripheral surface of the inner ring 15 with the tapered distal end 10 of the split collet 6. A taper fitting portion 21 is formed.

A cover wall 22 is formed at the distal end of the inner ring 15 so as to cover the distal end surface of the split collet 6. A tool insertion hole 23 for insertion is formed. The diameter of the tool insertion hole 23 is set to be larger than the diameter of the inner diameter hole 11 of the split collet 6, and the gap between the outer peripheral surface of the tool 3 and the tool insertion hole 23 in a state where the tool 3 is gripped by the split collet 6. A gap 24 is formed.

In the fastener 2 having the above structure, FIG.
When the outer ring 14 is screwed into the threaded portion 17 of the holder shank 1 in the mounted state as described above, the tapered fitting portion 21 of the inner ring 15 presses the split collet 6 in the axial direction and the radial direction, and the tapered hole 5 The split collet 6 is pushed in toward the back side. Thereby, the diameter of the split collet 6 is reduced, and the tool 3 inserted into the inner diameter hole 11 is gripped. Further, while holding the tool 3 in this manner, the seal ring 16 assembled on the back side of the inner ring 15 is crushed between the inner ring 15 and the tip end surface of the holder shank 1, and cut into the outer ring 14. Prevent oil leakage.

The tool holder of this embodiment has the structure as described above. The rear end of the holder shank 1 is mounted on the main shaft of a milling machine by using a pull stud bolt 4, and as shown in FIG. With the tool 3 inserted in the inner diameter hole 11 of the above, the split collet 6 is tightened by the tightening tool 2 to fix and hold the tool 3.

In this state, when a cutting fluid is supplied from the main shaft to the liquid supply hole 7 of the holder shank 1, the cutting fluid is sent to the back surface of the inner ring 15 of the fastener 2 through the slit groove 12 of the split collet 6. It discharges outward through a gap 24 between the insertion hole 23 and the tool 3. The discharged cutting fluid is supplied to the cutting position along the outer peripheral surface of the tool 3.

[0024]

As described above, according to the present invention, a gap is provided between a tool insertion hole provided in a collet tightening tool and a tool, and a cutting fluid is supplied through the gap. In addition, the liquid can be reliably supplied to the cutting position of the holeless tool through the inside of the holder, and the ability of the tool itself can be sufficiently exhibited by performing lubrication, cooling, and removing chips.

Further, since it is only necessary to tighten the split collet with the tightening tool and the operation is the same as that of a normal tool holder, a liquid supply structure having a simple structure and excellent operability can be realized.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing a tool holder according to an embodiment.

FIG. 2 is an exploded perspective view showing the fastening tool and the split collet of the same.

FIG. 3 is a longitudinal sectional view showing a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Holder shank 2 Tightening tool 3 Tool 5 Taper hole 6 Split collet 7 Liquid supply hole 12, 13 Slit groove 14 Outer ring 15 Inner ring 16 Seal ring 17 Screw part 18 Thread 23 Tool insertion hole 24 Clearance

Claims (2)

(57) [Claims] 1. A taper hole into which a split collet for gripping a cutting tool is inserted is provided on an inner peripheral surface of a tip portion of a holder shank. A liquid supply hole is provided, and a fastener for pressing the split collet toward the inner side of the tapered hole by pushing a screw is attached to a screw portion provided on the outer peripheral surface of the tip end portion of the holder shank. To the size that covers the tip of the split collet.
A tool holder for a cutting tool in which a tool insertion hole having a diameter larger than the inner diameter hole of the split collet is provided at the tip of the tightening portion. 2. An outer ring which engages with the threaded portion of the holder shank, an inner ring which is rotatably held inside the outer ring, and which is fitted to a tip end of a split collet. 2. The tool holder for a cutting tool according to claim 1 , wherein the tool holder is formed of a seal ring inserted between the inner ring and a tip end surface of the holder shank, and a tool insertion hole is provided at a tip end of the inner ring.