JPH05154735A - Tool holder - Google Patents

Abstract

PURPOSE:To shorten the working time for a tool change by braking and stopping the inertial rotation of a rotary shaft fitted with a tool in a short time when a tool holder is removed from a main spindle for a tool change in the tool holder removably fitted to the main spindle of a machining device. CONSTITUTION:A rotary shaft 10 is rotatably supported in a holder main body 9 via a hydrostatic bearing 15, and a tool 8 is fitted at the tip of the rotary shaft 10. An air driving system 16 for rotatively driving the rotary shaft 10 via the injection of air and an air stopping system 19 for stopping the rotation of the rotary shaft 10 via the counter-injection of air are provided between the holder main body 9 and the rotary shaft 10. An air passage 22 connected to an air feed source is provided on the holder main body 9, and a valve 28 capable of switching the feed of air to the air driving system 16 and the air stopping system 19 is provided in the air passage 22.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is detachably mounted on a spindle of a machining device such as a machining center and holds an air-driven rotary tool such as a grindstone for grinding or an end mill to perform machining such as grinding and cutting. It relates to the tool holder.

[0002]

2. Description of the Related Art As a conventional tool holder of this type, one having a structure as disclosed in, for example, JP-A-1-281861 is known.

In this conventional structure, a rotary shaft is rotatably supported in the holder body via a hydrostatic bearing, and a tool such as a grinding wheel is attached to the tip of the rotary shaft. An air turbine is provided between the holder body and the rotary shaft as an air drive mechanism for rotating the rotary shaft by jetting air. The holder body is provided with an air passage that is connected to the air supply source, and air is supplied to the air turbine through this air passage to rotate the rotating shaft at high speed, and at the same time, the static pressure is applied through the air passage. Air is supplied to the bearing so that the rotating shaft is supported by the holder body in a static pressure.

[0004]

However, in this conventional tool holder, since a stop mechanism for stopping the rotation of the rotary shaft is not provided, the tool holder is used for changing the tool in a machining apparatus such as a machining center. When removing the tool from the spindle of the processing device, you must wait for the tool holder to be removed until the inertial rotation of the rotary shaft falls below the specified number of revolutions after stopping the air injection from the air drive mechanism, and then changing the tool. There was a problem that it requires a long working time.

Further, in order to solve such a problem, it is possible to provide a mechanical brake mechanism on the tool holder. However, in such a structure, the structure becomes complicated and the tool rotates at a high speed. When stopping the rotating axis,
The brake shoes of the brake mechanism tended to wear, which caused a new problem in durability.

The present invention has been made by paying attention to the problems existing in such a conventional technique. The purpose of the present invention is to move the tool holder from the spindle of the processing apparatus for tool replacement or the like. When detaching, the inertial rotation of the rotary shaft can be stopped by braking in a short time, work such as tool change can be performed in a short time, and the stop mechanism is simple in structure and excellent in durability. To provide a tool holder that is

[0007]

In order to achieve the above object, according to the present invention, a main shaft of a processing apparatus is detachably mounted, and a rotary shaft is rotatably supported in a holder body via a static pressure bearing. In addition, in a tool holder in which a tool is attached to the tip of the rotary shaft, an air drive mechanism for rotating the rotary shaft by jetting air between the holder body and the rotary shaft, An air stop mechanism for stopping rotation by reverse injection of air is provided, an air passage connected to an air supply source is provided in the holder body, and the air drive mechanism and the air stop mechanism are provided in the air passage. A valve that can switch the supply of air is provided in and.

[0008]

[Operation] In the tool holder configured as described above, the tool holder, to which a predetermined tool is attached, is attached to the spindle of the machining device during machining, and at the same time as the attachment, the air passage is connected to the air supply passage on the spindle side. .. In this state, the air passage is connected to the air drive mechanism side by the switching operation of the valve.
As a result, the air supply path from the air supply source on the processing device side,
Air is supplied to the air drive mechanism through the air passage and is jetted to the rotary shaft, and the rotary shaft is rotationally driven at high speed, and machining such as cutting is performed by a tool at the tip of the rotary shaft.

When the tool holder is removed from the main shaft of the processing device for tool replacement or the like after completion of the processing, the air passage is connected to the air stop mechanism side by the valve switching operation. As a result, the supply of air to the air drive mechanism is stopped, and the air is supplied from the air supply source to the air stop mechanism via the air supply path and the air passage and is reversely injected to the rotary shaft. The rotation is braked.
Therefore, the inertial rotation of the rotary shaft can be stopped by braking in a short time, and work such as tool exchange can be performed in a short time. Further, by stopping the movement of the valve shaft at an intermediate position and appropriately adjusting the flow rate of air supplied to the air drive mechanism and the air stop mechanism, it is possible to obtain an arbitrary number of rotations of the rotary shaft.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is embodied in a tool holder for a machining center equipped with an automatic tool changer will be described in detail with reference to FIGS.

As shown in FIG. 2, a machining center 1 as a processing device has a bed 2 and a column 3.
The table 4 is supported on the bed 2 so as to be movable in the front-rear direction and the left-right direction in a horizontal plane, and the work W is detachably mounted on the upper surface thereof. The spindle head 5 is supported on the side surface of the column 3 so as to be movable in the vertical Z-axis direction.
A main shaft 6 is provided therein so as to be positively rotatable by a motor (not shown). The tool holder 7 is removably attached to the lower end of the spindle 6 by an unillustrated automatic tool changer,
A tool 8 such as an end mill is attached to its lower end.

As shown in FIG. 1, the tool holder 7 is provided with a substantially cylindrical holder body 9, and a taper shank portion 9a which can be fitted into the taper hole 6a of the main shaft 6 is provided at the upper end of the tool holder 7 and the outer circumference thereof. Has a holding groove 9b which can be engaged with a replacement arm of an automatic tool changing device (not shown). The tool holder 7 is releasably clamped to the spindle 6 by a clamp mechanism (not shown) with the tapered shank portion 9a of the holder body 9 fitted in the tapered hole 6a of the spindle 6.

As shown in FIGS. 1 and 3, the rotating shaft 10 is rotatably supported in the holder body 9 through a pair of bearing cylinders 11 and 12, and a tool 8 is chucked at its lower end by a chuck 13. It is detachably attached. A large number of ejection nozzles 14 are formed in the bearing cylinders 11 and 12, and air is ejected from the ejection nozzles 14 into the gap between the rotation shaft 10 and the bearing cylinders 11 and 12, whereby the rotation shaft 10 is rotated.
A hydrostatic bearing 15 is formed for bearing the.

The air drive mechanism 16 is provided between the holder body 9 and the rotary shaft 10, and has an impeller 17 formed on the outer periphery of the rotary shaft 10 and a bearing cylinder 11 facing the impeller 17. It is composed of a plurality of injection nozzles 18 formed. Then, while the main shaft 6 is positioned and fixed at a predetermined position with respect to the main shaft head 5, air is jetted from the jet nozzle 18 of the air drive mechanism 16 to the impeller 17, whereby the rotary shaft 10 is rotated. Is rotated counterclockwise at high speed.

The air stop mechanism 19 is the air drive mechanism 16 described above.
Underneath, between the holder body 9 and the rotating shaft 10, the impeller 20 formed on the outer circumference of the rotating shaft 10, and a plurality of reverse wheels formed on the bearing cylinder 11 facing the impeller 20. It is composed of an injection nozzle 21. Then, after the injection of the air from the injection nozzle 18 in the air drive mechanism 16 is stopped, the air is reversely injected from the reverse injection nozzle 21 of the air stop mechanism 19 to the impeller 20, whereby the rotation shaft 10 The inertial rotation is stopped by braking.

The air passage 22 is formed in the holder body 9 so as to communicate with the jet nozzles 14, and the air supply end of the air passage 22 changes its phase by 180 ° to the upper end surface of the holder body 9 outside the tapered shank portion 9a. It is opened in some places. The air supply passage 23 is provided in the main shaft 6 so as to face it.
Are formed so as to extend downward along the tapered hole 6a, the upper end of which is connected to an air supply source such as an air pump (not shown), and the lower end of which is opened at the lower end surface of the main shaft 6, respectively.

The cylindrical float member 24 is vertically movably fitted into the lower end opening of the air supply passage 23, and a joint 25 made of a soft material such as brass is fitted to the lower end thereof. The spring 26 is interposed between the lower end opening of the air supply path 23 and the float member 24, and the biasing force of the spring 26 always lowers the float member 24 in the vertical movement range regulated by the regulation pin 27. It is held in a protruding position.

When the main shaft 6 is positioned and stopped at a predetermined position and the taper shank portion 9a of the holder main body 9 is inserted into the taper hole 6a in a fixed state, the float member 24 receives the urging force of the spring 26. Moved upwards,
The bonded body 25 is pressed against the upper end surface of the holder body 9. At this time, when the air supply passage 23 and the air passage 22 are connected via the float member 24 and the joined body 25, and air is supplied from the air supply source to the air supply passage 23 in this state, the air is supplied to the air passage. It is led via 22 to each jet nozzle 14 for the hydrostatic bearing 15.

As shown in FIGS. 1 and 3, the valve 28 is provided in the air passage 22 of the holder body 9, and the valve 28
By this, the supply of air from the air passage 22 to the air drive mechanism 16 and the air stop mechanism 19 is switched, and the throttle valve is formed so that the air supply amount can be adjusted.

That is, the valve hole 29 is formed in the holder body 9 so as to extend in the direction intersecting the axis of the rotary shaft 10.
An air passage 22 is opened in the upper surface of the approximately middle portion. The drive air passage 30 is opened in the side surface of the valve hole 29 at a substantially middle portion, and communicates with each injection nozzle 18 of the air drive mechanism 16 via an annular passage 31 provided in the bearing cylinder 11. The stop air passage 32 is opened on the lower surface near one end of the valve hole 29, and communicates with each reverse injection nozzle 21 of the air stop mechanism 19 via an annular passage 33 provided in the bearing cylinder 11.

A valve shaft 34 serving as a valve body is slidably inserted into the valve hole 29 through a plurality of O-rings, and a drive air passage 30 and a stop air are provided near its intermediate portion and one end portion. Opening grooves 35 and 36 that can communicate with the passage 32 are formed. Then, according to the amount of movement of the valve shaft 34 in the valve hole 29 in the axial direction, the valve shaft 34 has a first switching position shown by a solid line in FIG. 3, a second switching position shown by a chain line, and The positioning is stopped at any intermediate position.

As shown in FIG. 2, a pair of support brackets 42 are erected on the upper surface of the table 4 in the machining center 1, and operation pins 42a and 42b are provided on the upper ends thereof so as to project inward. Then, with the tool holder 7 attached to the main shaft 6, the table 4 is moved to one side, and the one operation pin 42 a is moved to the one end portion 34 of the valve shaft 34.
By engaging with a, the valve shaft 34 is moved by a predetermined amount and switched to the first switching position shown by the solid line in FIG. As a result, the air passage 22 is communicated with the drive air passage 30 via the one opening groove 35 of the valve shaft 34, and the supply air is supplied to the air passage 22.
Is guided to each injection nozzle 18 of the air driving mechanism 16 from the driving air passage 30.

After the work W has been machined by the tool 8, the table 4 is moved to the other side, and the other operating pin 42b is engaged with the other end 34b of the valve shaft 34, and the valve shaft 34 is moved. Is moved by a predetermined amount to switch to a second switching position shown by a chain line in FIG. As a result, the air passage 22 is communicated with the stop air passage 32 via the other opening groove 36 of the valve shaft 34, and the supply air is supplied from the air passage 22 to the stop air passage 32.
Through the respective reverse injection nozzles 21 of the air stop mechanism 19.

Next, the operation of the machining center 1 having the tool holder 7 constructed as described above will be described. Now, in this machining center 1, the spindle 6
Is fixed to the spindle head 5 at a predetermined position, and a tool holder 7 to which a predetermined tool 8 is attached is attached to the lower end of the spindle 6 by an automatic tool changer in a stationary state via a key (not shown). .. After that, the table 4 is moved to one side by a movement command from the NC, and the valve shaft 34 is switched to the first switching position shown by the solid line in FIG. Groove 35
The air passage 22 communicates with the drive air passage 30 via the. After that, the table 4 is moved by the movement command from the NC and the differential pin 42a is separated from the valve shaft 34.

In this state, when air is supplied from the air supply source to the air supply passage 23 of the main shaft 6, the air passes through the air passage 22 in the holder body 9 and each jet nozzle 14 for the hydrostatic bearing 15. To the rotary shaft 1 from the jet nozzle 14
0 and the bearing cylinders 11 and 12 are jetted to form a hydrostatic bearing 15, and the rotary shaft 10 is hydrostatically supported on the holder body 9. At the same time, air flows from the air passage 22 through the drive air passage 30 to the air drive mechanism 16
And is jetted from the jet nozzle 18 toward the impeller 17, and the rotary shaft 10 is rotationally driven in the clockwise direction in FIG. 3 at a high speed. As a result, the work W is processed by the tool 8 at the tip of the rotary shaft 10 such as cutting.

When the machining of the work W by the tool 8 is completed, the table 4 is moved to the other side by the movement command from NC, and the valve shaft 3 is moved by the other operation pin 42b.
4 is switched to the second switching position shown by the chain line in FIG. 3, and the air passage 22 is communicated with the stop air passage 32 via the other opening groove 36 of the valve shaft 34. As a result, the supply of air to the air drive mechanism 16 is stopped, and the air is guided from the air passage 22 to the air stop mechanism 19 through the stop air passage 32, and the reverse injection nozzle 21 to the impeller 20 thereof.
The reverse injection is performed toward the vehicle to brake the rotation of the rotary shaft 10. At the same time, the table 4 is moved by the movement command from the NC, and the operating pin 42b is separated from the valve shaft 34. Then, when the rotation shaft 10 is decelerated below a predetermined rotation speed,
Stop air supply and change tools automatically. actually,
The time required for deceleration at a predetermined rotation speed or less is measured in advance, and the reverse injection is performed for the fixed time.

Therefore, after stopping the driving air, the rotating shaft 10
Does not inertially rotate for a long time, the inertial rotation of the rotary shaft 10 can be braked and stopped in a short time, and the subsequent replacement work of the tool holder 7 by the automatic tool changing device can be performed quickly and in a short time. Can be done.

When it is desired to change the number of rotations of the rotary shaft 10, the valve shaft 34 is moved to an intermediate position by changing the moving amount of the valve shaft 34, that is, the moving amount of the NC moving command of the table 4 at the time of valve switching. It can be stopped at various positions and the flow rate of air supplied to the air drive mechanism and the air stop mechanism can be changed.
This allows the rotation speed to be set to any value.

[0029]

Another Embodiment Next, another embodiment of the present invention will be described with reference to FIG. In this embodiment, the upper end of the air passage 22 provided in the holder body 9 is opened to the outer peripheral surface of the taper shank portion 9a, and the lower end of the air supply passage 23 provided in the main shaft 6 is tapered. It is opened on the inner peripheral surface of the hole 6a. When the taper shank portion 9a of the holder body 9 is fitted into the taper hole 6a of the spindle 6 and the tool holder 7 is attached to the tip of the spindle 6, the upper end opening of the air passage 22 is the lower end opening of the air supply passage 23. According to the department,
The air passage 22 is communicated with the air supply passage 23.

The present invention is not limited to the configuration of the above-described embodiment. For example, an air passage for supplying air to the jet nozzle 14 of the static pressure bearing 15 is provided with an air drive mechanism 16 and an air stop mechanism. Differently from the air passage 22 for supplying air to 19, the holder main body 9 may be formed, and the configuration of each part may be arbitrarily modified and embodied without departing from the spirit of the present invention. ..

[0031]

Since the present invention is configured as described above, when the tool holder is detached from the main shaft of the processing device for tool replacement or the like, the inertial rotation of the rotary shaft is stopped by braking in a short time. This brings about an excellent effect that work such as tool exchange can be performed in a short time.

Further, in the present invention, air is reversely injected from the air stop mechanism to the rotary shaft to stop the inertial rotation of the rotary shaft by braking, so that a mechanical brake mechanism is provided. Thus, there is an effect that the structure of the stop mechanism is simple and the durability is excellent.

Further, in the present invention, since the air passage is switched and connected by the valve between the air drive mechanism side and the air stop mechanism side, the air passages are separately provided for the air drive mechanism and the air stop mechanism. No need to
It is also possible to simplify the air supply structure.

Further, by stopping the valve shaft of the valve at an arbitrary intermediate position, the air can be supplied from the air passage to the air driving mechanism and the air stopping mechanism at an appropriate ratio. The rotational speed of the rotary shaft can be changed without changing the pressure, and an arbitrary rotational speed can be easily obtained while maintaining the bearing rigidity.

Furthermore, since the air supply to the air passage is introduced from the main shaft side, the air supply passage is communicated with the main shaft at the same time when the tool holder is attached to the main shaft, and a hose or the like is manually operated. It can be done automatically without connection work. Further, on the tool holder side, air can be supplied to the air drive mechanism and the air stop mechanism by switching from one air passage, so that air supply from the main spindle is sufficient for one system, and the structure on the main spindle side is also simplified.

[Brief description of drawings]

FIG. 1 is a sectional view of an essential part showing an embodiment of a tool holder embodying the present invention.

FIG. 2 is a front view showing a state in which the tool holder is attached to a spindle of a processing device.

FIG. 3 is an enlarged cross-sectional view taken along the line AA of FIG.

FIG. 4 is a partial cross-sectional view showing another embodiment of the air passage for the tool holder.

[Explanation of symbols]

1 Machining center as processing equipment, 6 spindles, 7
Tool holder, 8 tools, 9 Holder body, 10 Rotating shaft, 15 Hydrostatic bearing, 16 Air drive mechanism, 19 Air stop mechanism, 22 Air passage, 28 Switching and adjusting valve, 3
4 A valve shaft as a valve body.

Claims (3)

[Claims] 1. A main shaft of a processing apparatus, which is detachably mounted on the spindle.
In a tool holder in which a rotary shaft is rotatably supported in a holder main body via a hydrostatic bearing, and a tool is attached to the tip of the rotary shaft, a rotary shaft is provided between the holder main body and the rotary shaft. An air drive mechanism for rotationally driving by jetting air and an air stop mechanism for stopping the rotation of the rotating shaft by reverse jetting of air are provided, and an air passage connected to an air supply source is provided in the holder body. A tool holder, characterized in that a valve capable of switching the supply of air to the air drive mechanism and the air stop mechanism is provided in the air passage. 2. The tool holder according to claim 1, wherein the valve is a throttle valve capable of adjusting a flow rate of air supplied to the air drive mechanism and the air stop mechanism according to a movement amount of a valve shaft of the valve. 3. An air supply end of the air passage is formed so as to face a main shaft of a processing apparatus, and the holder main body is attached to the main shaft to be connected to an air supply passage formed on the main shaft side. The tool holder according to claim 1 or 2, characterized in that.