JP2001087986A - Cooling device for tool holder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prolong the durable years of an oil supplying/cooling device of a tool holder and allow use of a gas as a coolant. SOLUTION: This cooling device for the tool holder is equipped with a ring member 41 fitted on a minor diametric portion 22 of the tool holder 20 through bearings 44 and 45, a gap 48 to allow the supplied coolant to flow between the outer surface of the minor diametric portion 22 and the inner surface of ring member 41, cavities 60 and 61 whereto the coolant flowing through the gap 48 intrudes, and releasing holes 62 and 63 to put the cavities 60 and 61 in communication to outside. The coolant is exhausted following the route as the gap 48, cavities 60 and 61 and holes 62 and 63 to the outside, so that machining chips, etc., eventually contained in the coolant are exhausted to the outside via this route, and it is practicable to hinder chips from intruding into the bearings even in case no packing is used.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cooling device for supplying lubricating oil (cutting oil) to a tool holder mounted on a processing machine and also performing cooling, and more particularly to a cooling device capable of extending the service life and cooling. The present invention relates to a cooling device for a tool holder that can use gas as a material.

[0002]

2. Description of the Related Art For example, when a tool holder with a drill is mounted on a main shaft of a processing machine to form a hole in a workpiece, friction generated between the drill rotating at a high speed and the workpiece. If processing is not performed while removing heat, high-precision processing cannot be performed, and burn-in of the drill bit will occur. Therefore, conventionally, for example, Japanese Patent Application Laid-Open No. 63-169
No. 249, the cutting oil is supplied to the drill bit through the tool holder 1. This will be described with reference to FIG.

[0003] In FIG. 4, as is well known, a tool holder 1 is provided.
Has a columnar shape, and a tool H such as a drill (see FIG. 1) is attached to the tip 1a. The rear end 1b of the tool holder 1 is formed in a tapered shape, and the rear end 1b is fitted into the tapered hole 2a of the main shaft 2 of the machine tool.
The tool holder 1 is integrally attached to the main shaft 2 by drawing b into the main shaft 2.

An oil supply / cooling device 3 is mounted on the main body of the tool holder 1. The oil supply / cooling device 3 includes a ring-shaped sealing device 4 that is fitted to the outer periphery of the main body of the tool holder 1 in a liquid-tight manner, and an oil receiving device 5 that is connected to the sealing device 4. The oil receiving device 5 has a valve body 8 that opens against the elastic spring 7 when the tool holder 1 is mounted on the main shaft 2 and pressed against an oil introduction unit 6 provided on the machine tool. When the valve body 8 is opened, cutting oil also serving as a coolant is supplied from the oil introduction unit 6 into the oil receiving device 5.

The body of the tool holder 1 is provided with a plurality of radial holes 1c communicating with a center hole (not shown), and an annular groove 1d communicating with the outer peripheral opening of each hole 1c. Have been. For this reason, when the cutting oil is supplied into the oil receiving device 5, the cutting oil passes through the annular groove 1 d and the hole 1 c through the hole 9 provided in the sealing device 4 and passes through the center of the tool holder 1 body. It is supplied from a hole to a tool such as a drill (not shown) to prevent seizure of the drill bit and to cool the tool holder 1 and the tool.

Ball bearings 10 and 11 are attached to the inner periphery of both sides of the sealing device 4, respectively. Therefore, even when the tool holder 1 to which the oil supply / cooling device 3 is attached is mounted on the main shaft 2 and used, the high-speed rotation of the tool holder 1 is not hindered by the oil supply / cooling device 3. The ball bearings 10, 11 are provided on both sides of the annular groove 1d, and are provided on the ball bearings 10, 11 to prevent cutting oil from flowing from the annular groove 1d to the ball bearings 10, 11 side. Packings 12, 13 are provided on the side of the annular groove 1d.

[0007]

The tool holder 1 is used at a very high speed of several thousands to tens of thousands of revolutions per minute, and the packings 12, 13 are provided so as to be in sliding contact with the rotating tool holder 1. Over time, the packing wears out and needs to be replaced. On the other hand, the used cutting oil is collected after the drill is cooled, and after chips and the like in the oil are removed by a filter, the cutting oil is supplied from the oil introduction unit 6 into the oil receiving device 5 and reused.

For this reason, the cutting oil supplied from the oil introduction section 6 contains minute chips that could not be removed.
If the worn packings 12 and 13 are continuously used, small chips enter the ball bearings 12 and 13 and damage the ball bearings 12 and 13. For this reason, management of packing is indispensable, which causes an increase in processing cost and an increase in maintenance man-hours.

Recently, a method of using a gas instead of a liquid as a coolant has been sought. However, when a gas is used as a coolant, the amount of cutting oil, that is, lubricating oil supplied to the packings 12 and 13 is reduced. Therefore, the coefficient of friction with the tool holder 1 is increased, and the packings 12 and 13 are provided in a short time.
There is a problem that is worn out.

[0010] It is an object of the present invention to provide a cooling device for a tool holder, in which the management of packing is reduced and gas can be used as a coolant.

[0011]

SUMMARY OF THE INVENTION The present invention is directed to a tool holder which is mounted on a tool holder and supplies coolant from an outer surface of the tool holder to a hole formed along a central axis of the tool holder. In a cooling device for a tool, a ring member externally fitted to a tool holder via a bearing, and a supplied coolant flows between an outer surface of the tool holder and an inner peripheral surface of the ring member. The clearances formed and the holes for allowing the coolant to flow through the clearances and escape to the outside are provided.

The coolant is discharged to the outside through the clearance, through the clearance hole. Therefore, even if the coolant contains impurities such as minute chips, the impurities are discharged to the outside along with the flow of the coolant and the bearing is not damaged. In addition, since no packing is used, it is not necessary to control the wear, and gas can be used as a coolant.

[0013]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a cross-sectional view of a tool holder and a cooling device thereof according to an embodiment of the present invention.
FIG. 3 is a sectional view taken along line II-II of FIG. 1, and FIG. 3 is an enlarged view of a main part of a region III surrounded by a broken line in FIG.

In FIG. 1, the cooling device 30 attached to the tool holder 20 includes a ring-shaped sealing device 40 and an oil receiving device 50. The tool holder 20 according to the present embodiment includes a large diameter portion 21 and a small diameter portion 22 connected thereto.
And a tool mounting part 23 provided at the tip of the small diameter part 22.
And a tapered shank 24 provided on the back of the large diameter portion 21. The tool holder 20 is integrally attached to the main shaft 2 by the shank portion 24 being fitted to the main shaft 2 of the machine tool and being drawn into the main shaft 2 by a pulling tool (not shown).

A bottomed hole 25 is formed from the tip of the tool mounting portion 23 of the tool holder 20 to substantially the center of the small diameter portion 22 along the center axis thereof. A tool H such as a drill is inserted into the bottomed hole 25 from the tip side of the tool mounting portion 23,
The chuck 26 at the tip of the tool mounting part 23 is mounted on the tool holder 20 by being fastened. In the small diameter portion 22, four radial oil holes 27 communicating with the bottom portion of the bottomed hole 25 are formed in four sides (see FIG. 2) in this embodiment.

The sealing device 40, which will be described in detail later, includes a ring member 41 which is fitted to the small diameter portion 22 of the tool holder 20, and four oil holes formed in the small diameter portion 22 are provided at the center of the inner peripheral surface thereof. An annular groove 42 communicating with the opening of the hole 27 is formed. A radial through hole 43 is formed in the ring member 41 on the oil receiving device 50 side. The through hole 43 opens in the annular groove 42.

The oil receiving device 50 includes a support member 51.
The support member 51 has a bottomed sliding hole 52 parallel to the central axis of the tool holder 20, and an oil hole communicating the sliding hole 52 with the through hole 43 provided in the ring member 41. 53
And are drilled. The support member 51 is a ring member 4
The O-ring 54 is interposed between the two, and the oil hole 53 and the through-hole 43 communicate with each other in an air-tight and liquid-tight manner.

Into the sliding hole 52, a coolant introducing member 56 that slides in the direction of arrow A against a resilient spring 55 provided inside the sliding hole 52 is inserted. This coolant introduction member 5
6, an oil hole 57 extending along the center axis is penetrated, and further, four radial oil holes 58 communicating with the oil hole 57 are formed, and an annular shape is formed so as to communicate with the opening of each oil hole 58. A groove 59 is formed in the outer surface of the coolant introduction member 56.

Therefore, when the coolant introducing member 56 is pressed against the oil introducing portion 6 of the machine tool and slides to a position where the annular groove 59 communicates with the oil hole 53, the coolant and the cutting oil are discharged.
7, the oil hole 53, the through hole 43, the annular groove 42, the oil hole 27,
It is supplied to a tool (not shown) through the path of the bottomed hole 25. As a coolant, a cutting oil may be used as in the past, but in the present embodiment, a gas, for example, air is used as the coolant, and the cutting oil is mixed in a mist form and supplied along the path. As described below, the sealing device 40 is devised.

Ball bearings 44 and 45 are attached to the inner peripheral surfaces of both sides of the ring member 41 of the sealing device 40, respectively. Each of the ball bearings 44 and 45 has a stepped portion 49 provided on both side surfaces of the ring member 41.
a, 49b, and is fixed to the ring member 41 by ring-shaped stop members 46, 47 attached and fixed from the outside. The inner races 44a and 45a of the ball bearings 44 and 45 are formed on the small-diameter portion 2 of the tool holder 20.
Abut on the outer peripheral surface of the outer races 44b, 45b.
Is fixed to the ring member 41.

Between the ring member 41 and the small diameter portion 22,
As shown in FIG. 3, the inner peripheral surface of the ring member 41 is thinly cut so that a slight gap 48 is formed.
The gap 48 preferably ranges from several microns to several tens of microns. Each of the ball bearings 44 and 45 has an annular groove 42.
Bearing covers 44c and 45c are provided on the sides, respectively.
Although dust proofing is achieved, the bearing covers 44c,
Annular vacancies 60 and 61 communicating with the gaps 48 are formed on the annular groove 42 side of 45c by engraving the inner peripheral surface of the ring member 41 in an annular shape.

In the present embodiment, the size of the annular cavities 60, 61 is such that the bearing covers 44c, 45c
It is about half the size of Furthermore, each annular vacancy 60,
At 61, escape holes 62, 63 penetrating in the radial direction of the ring member 41 are formed substantially at the center. These escape holes 6
2 and 63 communicate with the outside via a gap 64 (FIG. 1) formed at a connection portion between the ring member 41 of the seal device 40 and the support member 51 of the oil receiving device 50.

The operation of the tool holder 20 and the oil supply / cooling device 30 having the above-described configuration will be described. When the tool holder 20 and the oil supply / cooling device 30 are attached to the machine tool, the coolant introducing member 56 slides in the direction of arrow A against the elastic spring 55, and the oil hole 57 and the oil hole 53 are moved. Communicate.
Thereby, the air mixed with the mist-like cutting oil supplied from the oil introduction unit 6 is supplied from the oil hole 57 to the oil hole 53.

The tool holder 20 starts rotating integrally with the main shaft 2 with the rotation of the main shaft 2 of the machine tool. Oiling / cooling device 4
0, the inner races 44a, 45a of the ball bearings 44, 45 rotate with the rotation of the tool holder 20, but the ring member 41 itself is
Keep it fixed at 0. The mist-like cutting oil supplied to the oil hole 53 is supplied to the through hole 43, the annular groove 42, the oil hole 27,
It is supplied to the tool cutting edge through the path of the bottomed hole 25, through the outer periphery of the tool or through hole in the tool H as is well known, to prevent seizure of the cutting edge, and to cool by the air flowing together. .

On the other hand, the air supplied to the annular groove 42 also flows into the minute gap 48 as shown by the white arrow in FIG. It flows into the gap 64 through the holes 62 and 63 and is discharged to the outside. By flowing air through such a path, the tool holder body is also cooled.

The air entering the gap 48 becomes a thin film of air and forms the ring member 41 and the small-diameter portion 22 of the tool holder 20.
And performs a bearing function, thereby suppressing the generation of frictional heat. There is no possibility that the mist-shaped cutting oil contains large chips that may damage the oil supply / cooling device, but only small chips on the order of microns.

However, the mist containing small chips is removed from the annular groove 42 → the gap 48 → the annular cavities 60,61 → the escape holes 62,6.
The air flowing through the path of 3 → gap 64 is discharged to the outside through the air, and does not enter the ball bearings 44 and 45 through the bearing covers 44c and 45c to be damaged.

As described above, in the present embodiment, the packing which is worn away is eliminated, and further, a passage through which the coolant flows to the outside is formed so that chips and the like do not damage the ball bearing, so that the durability is improved. As a result, the man-hour for replacing the packing is reduced, and the gas can be easily used as the coolant.

In this embodiment, the gas is used as the coolant, but it goes without saying that the same effect as described above can be obtained even if the liquid is used as the coolant as in the prior art. In this case, large chips and the like may be included in the coolant, but large chips are prevented from entering the minute gaps 48 from the annular groove 42, and only small chips are Although it invades, even in that case, it is discharged to the outside through the same route as in the above-described embodiment, so that the ball bearing is not damaged.

[0030]

According to the present invention, the gap through which the supplied coolant flows and the escape hole provided in front of the bearing and communicating with the gap and communicating with the outside are provided. Even if the swarf contains a swarf or the like, the swarf is discharged to the outside through a clearance hole along with the flow of the coolant, so that the bearing is not damaged. In addition, since no packing is used, it is not necessary to control the wear, and gas can be used as a coolant.

[Brief description of the drawings]

FIG. 1 is a perspective view of a tool holder according to an embodiment of the present invention;
It is sectional drawing of a cooling device.

FIG. 2 is a sectional view taken along line II-II shown in FIG.

FIG. 3 is an enlarged view of a main part of a region III surrounded by a broken line in FIG.

FIG. 4 is a configuration diagram of a conventional oil supply and cooling device for a tool holder.

[Explanation of symbols]

20: tool holder, 22: small diameter part, 23: tool mounting part,
Reference numeral 30: oil supply / cooling device, 40: sealing device, 41: ring member, 42: annular groove, 44, 45 ... ball bearing, 48: gap, 60, 61: annular vacant space, 62, 63 ...
Escape hole.

Claims (3)

[Claims] 1. A cooling device for a tool holder mounted on the tool holder and supplying a coolant from an outer surface of the tool holder to a hole formed along a central axis of the tool holder,
A ring member externally fitted to the tool holder via a bearing, a gap formed so that the supplied coolant flows between the outer surface of the tool holder and the inner peripheral surface of the ring member, A cooling device for a tool holder, comprising: an escape hole for allowing a coolant to flow through the gap and escape to the outside. 2. The method according to claim 1, wherein air is used as a coolant, and a cutting oil is mixed with the air in a mist form.
A cooling device for the tool holder as described in the above. 3. A bearing is provided on both sides of an opening in the outer surface for supplying a coolant from an outer surface to a hole formed along a central axis of the tool holder, and a bearing is provided before each bearing. 3. The cooling device for a tool holder according to claim 1, wherein vacant chambers are respectively connected to the escape holes.