JP2002126963A - Processing equipment - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To remove a tool holder from a spindle for tool change in a machining apparatus for performing machining by detachably attaching a tool holder to a mounting hole of a spindle, a rotary shaft in the tool holder. The inertial rotation is braked and stopped in a short time to shorten the working time for tool change. A rotating shaft is rotatably supported on a tool holder via a static pressure bearing, and a tool is attached to a tip of the rotating shaft. The tool holder 10 has a rotating shaft 2
An air drive mechanism 30 for driving the rotation of the rotary shaft 3 by injecting air and an air stop mechanism 33 for stopping the rotation of the rotating shaft 23 by injecting air in reverse are provided. Spindle 4
Is provided with a driving air supply path 41 and a stopping air supply path 48 connected to an air supply source, and the tool holder 10 is provided with a driving air passage 36 connected to the air driving mechanism 30 and the air stopping mechanism 33 and a stop. Air passage 39 is provided. The air supply ends of the air passages 36 and 39 are made to correspond to the open ends of the air supply passages 41 and 48 so as to be connected to each other when the tool holder 10 is mounted in the mounting hole 4 a of the main shaft 4. .

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a processing apparatus such as a machining center, and more particularly, to a tool spindle removably mounted on a spindle supported by a spindle head, and a grinding wheel, end mill, or the like mounted on the tool holder. The present invention relates to a processing apparatus which holds a rotary tool driven by air and performs processing such as grinding and cutting.

[0002]

2. Description of the Related Art As a conventional processing apparatus of this type, for example, a processing apparatus as disclosed in Japanese Patent Application Laid-Open No. 1-281861 is known.

In this conventional configuration, a rotary shaft is rotatably supported by a tool holder via a static pressure bearing, and a tool such as a grinding wheel is attached to a tip of the rotary shaft.
The tool holder is provided with an air turbine as an air drive mechanism for rotating the rotation shaft by jetting air. An air supply path connected to an air supply source is formed in the main shaft and the tool holder. Air is supplied to the air turbine via the air supply path, and the rotating shaft is driven to rotate at a high speed. Air is supplied to the hydrostatic bearing via the shaft, and the rotating shaft is hydrostatically supported on the tool holder.

[0004]

However, in this conventional processing apparatus, since a stop mechanism for stopping the rotation of the rotary shaft is not provided, when the tool holder is removed from the main spindle for tool exchange, the air is not removed. After stopping the injection of air from the drive mechanism, it is necessary to wait for the removal of the tool holder until the inertial rotation of the rotating shaft becomes equal to or less than a predetermined number of rotations, which requires a long working time for tool replacement. was there.

In order to solve such a problem, it is conceivable to provide a mechanical brake mechanism in the tool holder. However, in such a case, the structure becomes complicated and the rotation speed is increased. When stopping the rotating axis
Abrasion was likely to occur on the brake shoes of the brake mechanism, and a new problem occurred in durability.

SUMMARY OF THE INVENTION The present invention has been made in view of the problems existing in the prior art described above, and has as its object to remove a rotary shaft when removing a tool holder from a main spindle for tool exchange. The inertial rotation can be braked and stopped in a short time, the tool change operation can be performed in a short time, and the air stop mechanism is used to stop the rotating shaft, simplifying the structure of the stop mechanism. And can be
An object of the present invention is to provide a processing apparatus that can automatically connect an air supply path to an air drive mechanism and an air stop mechanism in a tool holder when the tool holder is mounted on a spindle.

Another object of the present invention is to utilize an air supply path for supplying either driving air or stopping air when performing machining using a tool requiring coolant. Accordingly, it is an object of the present invention to provide a processing apparatus capable of supplying a coolant onto a tool holder.

[0008]

SUMMARY OF THE INVENTION In order to achieve the above object, according to the present invention, a rotating shaft having a tool attached to a tip thereof is rotatable via a hydrostatic bearing in a mounting hole of a spindle supported by a spindle head. In a processing device in which a tool holder to be supported is detachably mounted, the tool holder has an air drive mechanism for driving the rotation shaft to rotate by jetting air, and the rotation of the rotation shaft is stopped by reverse injection of air. And a driving air passage and a stopping air passage connected to the air driving mechanism and the air stopping mechanism, respectively, and the main shaft is provided with a driving air passage connected to an air supply source. The air supply end of each air passage is connected to and separated from the open end of each air supply passage so as to be connected to each other when the tool holder is mounted in the mounting hole. One of the drive air supply path and the stop air supply path is shared with a coolant supply path for supplying coolant to a tool holder when performing machining using a tool requiring coolant. And a switching means for selectively connecting the air supply source and the coolant supply source to the one air supply path.

[0009]

According to the first aspect of the present invention, when the tool holder on which the predetermined tool is mounted is mounted in the mounting hole of the main shaft, a drive and stop air passage provided in the tool holder is provided on the main shaft. Connected to the driving and stopping air supply path. In this state, the driving air is supplied from the air supply source on the driving side to the air driving mechanism via the driving air supply path and the air passage and is jetted to the rotating shaft, and the rotating shaft is driven to rotate at high speed. Processing such as cutting is performed by a tool at the tip of the rotating shaft.

When the tool holder is removed from the mounting hole for tool exchange after the machining is completed, the supply of the driving air to the air driving mechanism is stopped, and the air passage for stopping is supplied to the air passage. The stop air is supplied to the air stop mechanism via the port, and is injected back to the rotating shaft to brake the rotation of the rotating shaft. Therefore, braking of the inertial rotation of the rotating shaft can be stopped in a short time, and a tool changing operation can be performed in a short time.

Further, when machining is performed using a tool that requires a coolant, a coolant supply source is connected to a driving or stopping air supply path instead of the air supply source. Processing is performed while coolant is supplied to the holder.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a vertical machining center equipped with an automatic tool changer embodying the present invention will be described below in detail with reference to the drawings.

As shown in FIGS. 1 and 2, a spindle head 1 of the machining center is formed in a substantially box shape, and a support cylinder 2 is fixed to a bottom thereof and a shielding cylinder 3 is fixed to a top thereof. . The hollow cylindrical main shaft 4 is rotatably inserted into and supported by the support cylinder 2 via a bearing 5, and a lower end thereof is formed with a tapered mounting hole 4a. The rotary cylinder 6 is screwed into the upper end thread portion 7 of the main shaft 4 and fixed by a locking nut 8. The rotary cylinder 6 is rotatably inserted into the shielding cylinder 3 with a predetermined gap. The gear 9 is fitted and fixed to an intermediate portion of the main shaft 4, and the main shaft 4 is rotationally driven via a gear transmission mechanism including the gear 9 with the rotation of a motor (not shown).

The tool holder 10 is removably mounted in the mounting hole 4a of the main shaft 4 by an automatic tool changing device (not shown), and a tapered shank portion 11a which can be inserted into the mounting hole 4a is provided at the upper end of the holder body 11. Be provided,
A holding groove 11b that can be engaged with a replacement arm of the automatic tool changer is formed on the outer periphery. The hollow cylindrical clamp shaft 12 is inserted and supported in the main shaft 4 so as to be movable in the vertical direction.
As shown in FIG. 2, it protrudes upward from the upper end of the main shaft 4.

A pressed nut 13 and a supporting nut 14 as actuated parts are screwed to an intermediate screw portion 15 of the clamp shaft 12, and an upper spring receiving ring 16 is joined to a lower surface of the supporting nut 14 to be joined thereto. . Lower spring receiving ring 17
The lower spring receiving ring 1 is disposed on the inner bottom of the main shaft 4.
A disc spring 18 as a first biasing member is interposed between the upper spring receiving ring 16 and the upper spring receiving ring 16. Then, the clamp shaft 12 is urged to move upward by the urging force of the disc spring 18.

A pull stud type clamp mechanism 19 is provided between the clamp shaft 12 and the holder main body 11, and includes a plurality of clamp balls 21 housed and supported in a support hole 20 at the lower end of the clamp shaft 12, And a pull stud 22 provided on the upper end of the holder body 11 so as to engage with the ball 21. Then, with this clamp ball 21 engaged with the pull stud 22,
When the clamp shaft 12 is pulled upward in the clamping direction by the biasing force of the disc spring 18, the holder body 11 is clamped in a state of being mounted in the mounting hole 4a. Further, the clamp shaft 12 is moved downward in the unclamping direction against the urging force of the disc spring 18, so that the clamp ball 21 is moved downward.
Is released from the pull stud 22, and the clamp of the holder body 11 is released.

A rotary shaft 23 is rotatably supported in the holder body 11 via a pair of upper and lower bearing cylinders 24 and 25.
A tool 26 such as a grinding wheel is detachably attached to the lower end thereof via a chuck 27. A large number of ejection nozzles 28 are formed in the bearing cylinders 24 and 25, and air is ejected from the ejection nozzles 28 into a gap between the rotating shaft 23 and the bearing cylinders 24 and 25 to support the rotating shaft 23. Static pressure bearing 29 is formed.

As shown in FIGS. 1 and 3, the air drive mechanism 30 is provided between the holder main body 11 and the rotating shaft 23, and has an impeller 31 formed on the outer periphery of the rotating shaft 23; And a plurality of injection nozzles 32 formed in the upper bearing cylinder 24 so as to face the base 31. When the spindle 4 is stopped at a predetermined position with respect to the spindle head 1, air is ejected from the ejection nozzle 32 of the air drive mechanism 30 to the impeller 31, thereby rotating the rotating shaft 23 in FIG. At high speed in the counterclockwise direction.

The air stopping mechanism 33 is provided with the air driving mechanism 30.
An impeller 34 provided between the holder main body 11 and the rotating shaft 23 below and below the outer periphery of the rotating shaft 23;
A plurality of reverse injection nozzles 35 are formed in the upper bearing cylinder 24 so as to face the impeller 34. And
After the injection of the air from the injection nozzle 32 in the air drive mechanism 30 is stopped, the air is reversely injected from the reverse injection nozzle 35 of the air stop mechanism 33 to the impeller 34, so that the inertia rotation of the rotating shaft 23 is performed. Is stopped.

As shown in FIG. 1, the driving air passages 36 are formed in the holder main body 11, and each of the ejection nozzles 2 is formed through an annular passage 37 provided on the inner peripheral surface of the holder main body 11.
8 and to each injection nozzle 32 of the air drive mechanism 30 via an annular passage 38 provided on the outer peripheral surface of the upper bearing cylinder 24. The stop air passage 39 is formed in the holder main body 11 and the pull stud 22 and is connected to each reverse injection nozzle 35 of the air stop mechanism 33 via an annular passage 40 provided on the outer peripheral surface of the upper bearing cylinder 24. .
The air supply end of the drive air passage 36 is opened at two positions on the upper end surface of the holder body 11 outside the tapered shank portion 11a with a phase change of 180 °, and the air supply end of the stop air passage 39 is provided with a pull stud. There are 22 openings.

A first air supply passage 41 as a driving air supply passage is provided in a hollow portion of the clamp shaft 12, and a lower end thereof is opened on an outer peripheral surface of the clamp shaft 12. The two inclined supply passages 42 are formed so as to extend downward along the mounting holes 4a, and the upper ends thereof are connected to the first air supply passage 41 via the annular passage 43, and the lower ends thereof are the driving air passages. Opened at the lower end surface of the main shaft 4 in opposition to the two air supply ends.

A cylindrical float member 44 is vertically movably fitted into the lower end opening of the inclined supply passage 42, and a joint 45 made of a soft material such as brass is fitted at the lower end thereof. The spring 46 is interposed between the lower end opening of the inclined supply path 42 and the float member 44, and is always below the vertical movement range where the float member 44 is regulated by the regulating pin 47 by the urging force of the spring 46. Position.

Then, the tapered shank portion 11 of the holder body 11 is kept in a state where the main shaft 4 is stopped at a predetermined position.
When a is inserted into the mounting hole 4a via a key (not shown) in a localized state, the float member 44 is moved upward against the urging force of the spring 46, and the joined body 45 is
Is pressed against the upper end surface of the At this time, the inclined supply path 42 is connected to the air supply end of the driving air passage 36 via the float member 44 and the joined body 45.

A second air supply path 48 as a stop air supply path is provided in the hollow portion of the main shaft 4, and a lower end thereof is opposed to an upper end opening of the stop air path 39.
It is opened at the inner top of the mounting hole 4a via a supply path 49 formed in the clamp shaft 12. And the holder body 1
When 1 is inserted into the mounting hole 4a, the second air supply path 48 is connected to the air supply end of the stop air path 39 via the supply path 49.

As shown in FIG. 2, a cylindrical cylinder 50 is provided.
Is fixed on the shielding cylinder 3, and a lid body 51 is attached to an upper end thereof. A hollow cylindrical operating shaft 52 as an operating member is vertically movably accommodated in the cylinder 50, and has a recess 52a at the lower end thereof. The piston 53 is fixed to the middle of the operation shaft 52 by a nut 54. The piston 53 divides a cylinder chamber in the cylinder 50 into a lower pressurizing chamber 50a and an upper pressurizing chamber 50b.

The pressing body 55 is fixed to the lower end of the operating shaft 52 by a screw 56 in the recess 52a, and opposes the upper surface of the pressed nut 13 so as to be able to contact and separate therefrom. A spring 57 as a second urging member is interposed between the lid 51 and the piston 53, and the operating shaft 52 is urged to move downward by the urging force of the spring 57. In this embodiment, the downward urging force applied to the operating shaft 52 by the spring 57 is set to be smaller than the upward urging force applied to the clamp shaft 12 by the disc spring 18. ing.

The switching air port 58 is connected to the cylinder 50.
And is communicated with the lower pressurizing chamber 50a. The hydraulic port 59 is formed in the lid 51 and communicates with the upper pressurizing chamber 50b. The air supply port 60 is formed in the operating shaft 52 and the pressing body 55, and is opened in the recess 52 a so as to face the upper end opening of the second air supply path 48. The stop air port 61 is formed in the cylinder 50 and has an annular passage 62.
Through the air supply port 60.

The connecting cylinder 63 is fixedly or integrally protruded from the upper end of the rotary cylinder 6. A seal ring 64 is provided on the inner surface of the lower end of the recess 52a so as to face the connecting cylinder 63 so as to be able to come and go. ing. The connecting cylinder 63 and the seal ring 64 constitute a connecting means. As shown in FIG. 4, the operating shaft 52 is moved downward by the urging force of the spring 57, and the pressing body 55 is placed on the clamp shaft 12. When contacted with the pressed nut 13, the seal ring 64
3 and in this state, the air supply port 60 is
a to the second air supply path 48.

A support bracket 65 is mounted on the upper surface of the spindle head 1, and a cylindrical coupling 66 is rotatably supported on the support bracket 65 via a bearing 67. A rotary joint 68 for supplying drive air and coolant is mounted on a support bracket 65 via a mounting plate (not shown), and a rotary pipe 68 a protruding from the lower surface thereof is screwed and fixed to the coupling 66. And
The upper end of the clamp shaft 12 is fitted into the coupling 66 so as to be integrally rotatable and relatively movable in the axial direction, and the inside of the rotary joint 68 is connected to the first air supply passage in the clamp shaft 12 via the coupling 66. 41.

As shown in FIG. 2, a supply circuit for supplying air or hydraulic pressure to the pressurizing chambers 50a and 50b in the cylinder 50 includes an air pump 69 as an air supply source, a switching valve 70, and an air supply source. Communicating with the exhaust units 71 and 72,
And second air paths 73 and 74, and an air-hydro booster 75. The switching valve 70 includes first to third switching units 70a, 70b, and 70c, and the first and second air paths 73 and 74 are switched by the switching.
Alternatively, it is arbitrarily connected to the exhaust units 71 and 72.

The air-hydro booster 75 has a cylinder chamber 76 and a pressure increasing chamber 77. The piston 78 is movably provided in the cylinder chamber 76.
8, the first and second pressurizing chambers 76
a and 76b. The piston rod 79 protrudes from the piston 78 into the pressure increasing chamber 77 and the oil tank 80
The pressure of the oil supplied to the pressure increasing chamber 77 is increased by the movement of the piston rod 79.

The first air path 73 has two air paths 7
3a and 73b, one of the air paths 73a is connected to the lower pressurizing chamber 50a in the cylinder 50 via the switching air port 58, and the other air path 73b
Is connected to the first pressurizing chamber 76a of the air-hydro booster 75. The second air supply path 74 is connected to a second pressurizing chamber 76b of the air-hydro booster 75. Further, the pressure increasing chamber 77 is connected to the upper pressurizing chamber 50 b in the cylinder 50 via the hydraulic pressure port 59 via a hydraulic pressure output path 81.

As shown in FIG. 2, a supply circuit for supplying drive air and coolant to the first air supply path 41 through the rotary joint 68 includes an air pump 82 as a drive air supply source, a coolant A coolant supply pump 83 as a supply source, and on-off valves 84 and 85 as switching means connected to their supply paths to selectively connect the air pump 82 and the coolant supply pump 83 to the rotary joint 68. It has.

Then, as shown in FIG.
When performing machining using an air-driven rotary tool 26 such as an end mill attached to the 0 rotary shaft 23,
One open / close valve 84 is opened, and driving air is supplied from the air pump 82 to the air driving mechanism 30 in the tool holder 10 via the first air supply path 41 and the like. In addition, when processing is performed using a so-called shaft center oil supply tool that requires a coolant (not shown), the other open / close valve 85 is opened, and the coolant supply pump 83 supplies the first air supply passage 41 and the like. The coolant is supplied to the tool holder via.

As shown in FIG. 2, a supply circuit for supplying stop air or the like from the stop air port 61 to the second air supply path 48 via the air supply port 60 includes an air pump 86, a pressure switching means, and the like. The shut-off pressure reducing valve 87, the cleaning pressure-reducing valve 88, the stop pressure-reducing valve 87, and the on-off valve connected to their supply paths so as to selectively connect the cleaning pressure-reducing valve 88 to the stop air port 61 8
9, 90. The air pumps 69, 8
Although 2,86 are separately numbered, they are actually one.

After the machining, the tool holder 10
When the rotation of the rotating shaft 23 is stopped, the supply of the driving air is stopped, and as shown in FIG.
When the air supply port 60 is connected to the second air supply path 48 via the recess 52a by the contact engagement between the seal ring 64 and the connection cylinder 63 with the downward movement of the one opening / closing valve 8
9 is opened, and the stop air reduced in pressure from the air pump 86 through the stop pressure reducing valve 87 is supplied to the air stop mechanism 33 in the tool holder 10 via the second air supply path 48 and the like.

After the rotation shaft 23 is braked to a predetermined speed or less and the supply of the stop air is stopped, the clamp shaft 12 is moved downward by the downward movement of the operation shaft 52 as shown in FIG. When the tool holder 10 is removed from the mounting hole 4a of the main shaft 4, the other on-off valve 90 is opened, and the cleaning air reduced in pressure from the air pump 86 through the cleaning pressure reducing valve 88 is supplied to the second air supply path. It is supplied to the mounting hole 4a via 48 or the like.

In this embodiment, as shown by a chain line in FIG. 1, a rotation sensor 91 is provided so as to face the rotation shaft 23 or the chuck 27, and the rotation sensor 91 rotates the rotation shaft 23. The number is to be detected. Further, a vibration sensor 92 may be built in the support cylinder 2 so that the number of rotations of the rotating shaft 23 is detected by a change in vibration.

The detected value is used to confirm a predetermined number of revolutions when the rotating shaft 23 is driven,
3 is used as a switching signal of the on-off valve 89 when the braking is stopped.

Next, the operation of the machining center configured as described above will be described. Now, FIGS. 1 and 2
The state in which the spindle 4 is stopped at a predetermined position with respect to the spindle head 1, the tool holder 10 is mounted in the mounting hole 4 a of the spindle 4, and the tool holder 10 is clamped to the spindle 4 by the clamp mechanism 19. It is shown. In this state, the air supply end of the drive air passage 36 is connected to the joint 45 at the lower end opening of the inclined supply passage 42, and the drive air passage 36 is connected to the clamp shaft 1 via the inclined supply passage 42.
2 is connected to the first air supply path 41. The upper end opening of the stop air passage 39 is connected to the lower end opening of the supply passage 49, and the stop air passage 39 is connected to the second air supply passage 48 in the main shaft 4 via the supply passage 49. .

Further, in this state, the switching valve 70 of the air and oil pressure supply circuit is switched to the switching portion 70a, and the air from the air pump 69 is supplied from the first air path 73 to the cylinder 50 via the air path 73a. The air is supplied to the lower pressurizing chamber 50a and to the first pressurizing chamber 76a of the air-hydro booster 75 via the air path 73b. For this reason, the piston 78 and the piston rod 79 of the air-hydro booster 75 are moved upward in FIG. 2, the oil pressure in the pressure increasing chamber 77 becomes zero, and the pressure in the upper pressurizing chamber 50b of the cylinder 50 also becomes zero. I have.

As a result, as shown in FIG. 2, the piston 53 in the cylinder 50 is moved upward against the urging force of the spring 57, the operating shaft 52 is held at the upper position, and the pressing body 55 is clamped. The seal ring 64 is separated from the connection cylinder 63 while being separated from the pressed nut 13 on the shaft 12. Therefore, the clamp shaft 12 is
8, the clamp mechanism 19 is held in a clamped state by being pulled up in the clamp direction.

In this state, when the open / close valve 84 of the driving air supply circuit is opened, the driving air from the air pump 82 is supplied to the rotary joint 68, the coupling 66, the first air supply path 41, and the inclined supply path 42. Through the driving air passage 36 in the tool holder 10, and then each ejection nozzle 28
Is spouted into the gap between the rotating shaft 23 and the bearing cylinders 24 and 25 to form a hydrostatic bearing 29, and the rotating shaft 23 is statically supported on the holder body 11. At the same time, the driving air is supplied from the driving air passage 36 to the air driving mechanism 3.
0, and is injected from the injection nozzle 32 toward the impeller 31, and the rotating shaft 23 is driven to rotate clockwise in FIG. 3 at high speed. Thereby, the tool 2 at the tip of the rotating shaft 23
At 6, the work such as cutting is performed on the work.

On the other hand, when machining is performed with a tool holder provided with a tool requiring a coolant mounted on the main shaft 4, the open / close valve 85 of the coolant supply circuit is opened,
Coolant from the coolant supply pump 83 is supplied to the tool holder via the rotary joint 68, the coupling 66, the first air supply path 41, and the inclined supply path 42, and the tool or the workpiece is cooled.

When the machining by the tool 26 on the rotary shaft 23 is completed, the on-off valve 84 of the driving air supply circuit is opened.
Is closed, and the supply of the driving air from the air pump 82 to the air driving mechanism 30 and the like is stopped. Thereafter, the switching valve 70 of the air and oil pressure supply circuit is switched to the switching unit 70b, the air supply from the air pump 69 is cut off, and the first and second air paths 73, 74 are exhausted by the exhaust units 71,7.
2 connected to the atmospheric pressure, the air-hydro booster 7
The pressure in both the pressurizing chambers 76a, 76b and the pressurizing chambers 50a, 50b in the cylinder 50 becomes zero.

As a result, as shown in FIG.
2 is moved downward together with the piston 53 by the urging force of the spring 57, the pressing body 55 is brought into contact with the pressed nut 13 on the clamp shaft 12, and the seal ring 64 is brought into contact with the connection cylinder 63. Accordingly, the air supply port 60 is connected to the second air supply path 48 via the recess 52a. At this time, since the downward urging force applied to the operating shaft 52 by the spring 57 is set to be smaller than the upward urging force applied to the clamp shaft 12 by the disc spring 18, the clamp shaft 12 is not moved downward and is not unclamped.

In this state, the on-off valve 89 of the stop air supply circuit is opened, and the stop air reduced in pressure from the air pump 86 through the stop pressure reducing valve 87 is supplied to the stop air port 61, the air supply port 60, It is guided to the stopping air passage 39 in the tool holder 10 via the 2 air supply passage 48 and the supply passage 49. After that, the stop air is guided from the stop air passage 39 to the air stop mechanism 33, and is injected back from the reverse injection nozzle 35 toward the impeller 34, so that the rotating shaft 2
3 is braked. Accordingly, the rotating shaft 23 does not coast for a long time, and the coasting of the rotating shaft 23 can be stopped in a short time by braking. Can be performed quickly and in a short time.

When the rotation of the rotating shaft 23 is braked in this way and the rotation sensor 91 detects that the number of rotations has decreased to a predetermined value or less, the on-off valve 89 is closed and the supply of the stop air is stopped. . Then, the replacement arm of the automatic tool changer (not shown) is inserted into the holding groove 11 of the tool holder 10.
b, the switching valve 70 of the air and hydraulic supply circuit is switched to the switching section 70c, and the air from the air pump 69 is supplied to the air-hydro booster 7 via the second air path 74.
5 is supplied to the second pressurizing chamber 76b. As a result, the piston 78 and the piston rod 79 of the air-hydro booster 75 are moved downward in FIG. 2, and the oil pressure in the pressure increasing chamber 77 is increased. It is supplied to the pressurizing chamber 50b.

As a result, as shown in FIG.
2 is further moved downward integrally with the piston 53 to a position where it comes into contact with the rotary cylinder 6, and the clamp shaft 12 is moved downward in the unclamping direction via the pressing body 55 and the pressed nut 13, and the clamping mechanism The clamp by 19 is released. After that, the tool holder 1 is
0 is removed from the mounting hole 4a of the main shaft 4. At this time,
The on-off valve 90 of the cleaning air supply circuit is opened,
The cleaning air reduced in pressure from the air pump 86 through the cleaning pressure reducing valve 88 is supplied to the stop air port 6.
1. Air supply port 60, second air supply path 48, and supply path 4
9, the toner is supplied to the mounting hole 4a, and the mounting hole 4a and the taper shank portion 11a of the tool holder 10 are cleaned.

The present invention is not limited to the configuration of the above-described embodiment, but can be embodied with the following modifications without departing from the spirit of the present invention. (1) The first air supply path 41 in the clamp shaft 12 is used as a stop air supply path, the second air supply path 48 in the main shaft 4 is used as a drive air supply path, and the operating shaft 5 is used.
2 moves downward from the air supply port 60 to the second air supply path 48 in a state where the seal ring 64 is in contact with and engaged with the connection cylinder 63 and the air supply port 60 is connected to the second air supply path 48. , The driving air or the cleaning air is selectively supplied.

(2) An air passage for supplying air to the ejection nozzle 28 of the static pressure bearing 29 is formed in the holder body 11 separately from the driving air passage 36 and the stopping air passage 39.

[0052]

Since the present invention is configured as described above, it has the following excellent effects.

According to the present invention, when the tool holder is removed from the spindle for tool change, the inertia rotation of the rotary shaft can be stopped in a short time by braking, and the tool changing operation can be performed in a short time. Can be. Further, since the air stop mechanism is provided for stopping the rotating shaft, the structure of the stop mechanism can be simplified and the durability can be improved. Furthermore, when the tool holder is mounted on the spindle, the air supply path to the air drive mechanism and the air stop mechanism in the tool holder is automatically connected and formed, so that the tool changing operation can be performed quickly.

When machining is performed using a tool that requires coolant, the coolant is placed on the tool holder by using an air supply path for supplying either driving air or stopping air. Can be supplied, and the supply path of the driving air and the coolant can be simplified.

[Brief description of the drawings]

FIG. 1 is a partial sectional view showing an embodiment in which a processing apparatus of the present invention is embodied in a vertical machining center, and particularly showing a substantially lower half of a spindle head.

FIG. 2 is a partial sectional view showing a substantially upper half of a spindle head.

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

FIG. 4 is a partial cross-sectional view showing a state where the operating shaft has been moved downward by a predetermined amount from the position shown in FIG. 2;

FIG. 5 is a partial cross-sectional view showing a state where the operation shaft has been further moved downward from the position shown in FIG. 4;

[Explanation of symbols]

1 spindle head, 4 spindles, 4a mounting holes, 10 tool holders, 23 rotating shafts, 26 tools, 29 hydrostatic bearings,
30 air drive mechanism, 33 air stop mechanism, 36 drive air path, 39 stop air path, 41 first air supply path as drive air supply path, 48 second air supply path as stop air supply path, 82, an air pump as a driving air supply source, 83, a coolant supply pump as a coolant supply source, 84, 85 an opening / closing valve constituting switching means.

Claims (1)

[Claims] 1. A machining apparatus in which a tool holder for rotatably supporting a rotating shaft having a tool attached to a tip via a hydrostatic bearing in a mounting hole of a spindle supported by a spindle head is detachably mounted. The tool holder is provided with an air drive mechanism for rotating the rotating shaft by jetting air, and an air stopping mechanism for stopping the rotation of the rotating shaft by reverse jetting of air. A driving air passage and a stopping air passage respectively connected to an air stopping mechanism are provided, and the driving shaft is provided with a driving air supply passage and a stopping air supply passage connected to an air supply source; The air supply end of each air passage is connected to the open end of each air supply passage so as to be connected to each other when the tool holder is mounted in the mounting hole, and the driving air supply passage or the stop air One of the supply paths is shared with a coolant supply path for supplying a coolant to a tool holder when machining is performed using a tool requiring a coolant, and the air supply source and the coolant supply source are connected to the one air supply source. A processing apparatus comprising a switching means for selectively connecting to a supply path.