JP3719785B2 - spindle - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a spindle provided with a static pressure gas bearing, and more particularly, to a measure for utilizing exhaust from a static pressure gas bearing.
[0002]
[Prior art]
This type of spindle introduces compressed gas supplied from the outside to a static pressure gas bearing through an air supply passage in the housing, as described in, for example, Japanese Patent Application Laid-Open No. 8-111002. The rotating shaft is rotatably supported by forming a gas film, and since it can rotate at high speed and has very little vibration, it is used for precision work such as drilling of printed circuit boards. .
[0003]
By the way, in the above publication, a second exhaust passage for guiding the gas to the chuck at the tip of the rotary shaft separately from the first exhaust passage for exhausting the gas discharged from the static pressure gas bearing directly to the outside of the housing. Is provided. When the chuck is closed, exhaust is performed via the first exhaust passage, while when the chuck is open, exhaust is performed via the second exhaust passage. It is possible to prevent foreign matter from entering the chuck when the is opened.
[0004]
[Problems to be solved by the invention]
However, in the conventional spindle, when the chuck is closed, the gas discharged from the static pressure gas bearing is discharged to the outside as it is through the first exhaust passage. It is difficult to say that exhaust from gas bearings is fully utilized.
[0005]
The present invention has been made in view of such a point, and the main object of the present invention is to effectively exhaust the static pressure gas bearing by improving the structure of the spindle having the static pressure gas bearing. It is to be able to utilize.
[0006]
[Means for Solving the Problems]
In order to achieve the above object, in the present invention, since a spindle equipped with a static pressure gas bearing is used at high speed rotation, a rotary tool such as a drill is overheated during processing and its life is likely to be shortened. Focusing on the situation, the exhaust from the static pressure gas bearing is utilized for cooling the rotary tool to extend its life.
[0007]
Specifically, according to the first aspect of the present invention, the rotary shaft is rotatably supported by the housing via the static pressure gas bearing, and the rotary tool rotates at the shaft end portion of the rotary tool. has one end portion attached together, by being supplied with gas from the gas supply source to operate the externally pressurized gas bearing away spindle is premised.
[0008]
Then, provided near the site of the rotating shaft end of the housing, and Luca bar to form an annular gap around the one end portion of the and rotary shaft portion near has covered, it is discharged from the externally pressurized gas bearing And a gas passage for introducing gas into the cover.
[0009]
In the above configuration, the gas discharged from the static pressure gas bearing of the spindle is introduced into a cover provided in the vicinity of one end of the rotary shaft in the housing via the gas passage. And the gas in a cover is discharged outside from the annular clearance around the one end part of a rotating shaft. At this time, one end of the rotating shaft is cooled by the gas discharged from the gap, and as a result, the rotating tool attached to the one end of the rotating shaft is also cooled.
[0010]
In the invention of claim 2, in the invention of the claim 1, on which the cover has a first cover, provided in a state above the Tsu Do heavy in the first cover, the shaft portion of the rotary tool can be inserted And a second cover having an exhaust port connectable to an intake means for sucking gas discharged from a gap between the first cover and one end of the rotating shaft.
[0011]
In the above-described configuration, the gas discharged from the annular gap between the first cover and one end of the rotating shaft is introduced into the second cover and is discharged to the outside from the exhaust port of the second cover by the suction means. Discharged. Thereby, since the discharge of the gas from the annular gap is smoothed, the cooling effect on the rotary tool is increased accordingly. In addition, scattering of dust around the gas due to the discharge of the gas can be prevented.
[0012]
Rotation in the invention of claim 3, standing on the same assumption as in the invention described in claim 1, provided in the vicinity portion of the rotary shaft one end of the housing, which is attached to and rotating shaft end portion has covered the site near and Luca bar to form an annular gap around the shaft portion of the tool, the gas discharged from the externally pressurized gas bearing and the like and a gas passage for introducing into the cover.
[0013]
In the above configuration, the gas discharged from the static pressure gas bearing of the spindle is introduced into a cover provided in the vicinity of one end of the rotary shaft in the housing via the gas passage. And the gas in a cover is discharged outside from the cyclic | annular clearance gap around the axial part of the rotary tool attached to the one end part of a rotating shaft. At this time, since the shaft part itself of the rotary tool is cooled by the gas discharged from the gap, the cooling action on the rotary tool is higher than in the case of the invention of claim 1. Moreover, since the said gas is discharged from the surroundings of the axial part of a rotary tool, removal of dusts, such as a chip generated with the process by a rotary tool, is also performed.
[0014]
In the invention of claim 4, in the invention of the third aspect, after the cover is a first cover, provided in a state above the Tsu Do heavy in the first cover, the shaft portion of the rotary tool A second cover having an insertable opening and an exhaust port connectable to an intake means for sucking gas discharged from a gap between the first cover and the rotary tool shaft is provided.
[0015]
In the above configuration, the gas discharged from the gap between the first cover and one end of the rotating shaft is introduced into the second cover and discharged to the outside from the exhaust port of the second cover by the suction means. Thereby, since the discharge of the gas from the said clearance gap is smoothed, the cooling effect | action with respect to a rotary tool becomes high by that much. Moreover, since the dust removed by the gas discharge is sucked together with the gas by the suction means, the dust is prevented from being scattered around.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0017]
(Embodiment 1)
FIG. 1 shows an overall configuration of a spindle A according to Embodiment 1 of the present invention, and this spindle A is used for drilling a printed circuit board.
[0018]
The spindle A includes a substantially cylindrical housing 1 arranged so as to extend in the vertical direction in FIG. 1, a thrust air bearing 2 as a static pressure gas bearing, and radial air bearings 3 and 3 in the housing 1. The rotating shaft 4 is rotatably supported, and the electric motor 5 is disposed between the housing 1 and the rotating shaft 4 and rotationally drives the rotating shaft 4.
[0019]
The thrust air bearing 2 is disposed in the upper part of the housing 1 and is a state in which a disc-shaped thrust collar 6 provided integrally with the rotating shaft 4 and the thrust collar 6 are sandwiched in the axial direction at a predetermined interval. And a pair of upper and lower bearing flanges 7 and 8. A plurality of air supply holes 7 a, 7 a,..., 8 a, 8 a, etc. provided so as to penetrate the flanges 7, 8 in the axial direction are arranged at predetermined pitch intervals in the circumferential direction. Has been. A first annular passage 9 is provided on the upper surface of the upper flange 7 so as to communicate with the air supply holes 7a, 7a,.
[0020]
On the other hand, the radial air bearings 3, 3 are provided in two upper and lower stages below the thrust air bearing 2, and are respectively fitted in the portions of the rotating shaft 4 facing each other with a predetermined clearance. A bearing sleeve 10 is fixed to the housing 1. In each bearing sleeve 10, a plurality of air supply holes 10a, 10a,... Provided so as to penetrate each sleeve 10 in the radial direction are arranged at predetermined pitch intervals in the circumferential direction. A lower flange 8 of the thrust air bearing 2 is integrally provided at the upper opening edge of the bearing sleeve 10 of the upper radial air bearing 3.
[0021]
The electric motor 5 is disposed between the upper and lower radial air bearings 3 and 3 and is a stator comprising an electromagnetic coil fixed to the housing 1 in a state of being externally fitted to the rotary shaft 4 with a predetermined clearance. 5a and a rotor 5b which is disposed on the inner peripheral side of the stator 5a and is made of a permanent magnet which is provided on the outer peripheral side of the rotating shaft 4 so as to rotate together.
[0022]
The upper end of the housing 1 is provided so as to be connectable to an air supply device F as a gas supply source and receives an air supply from the air supply device F, and from the air supply port 1a. An exhaust port 1b is provided for discharging the air that has been supplied to the thrust air bearing 2 and the radial air bearings 3 and 3 from the thrust air bearing 2 and the radial air bearings 3 and 3 to the outside of the housing 1. ing.
[0023]
Further, the housing 1 communicates with the air supply holes 8a, 8a,... Of the lower flange 8 of the thrust air bearing 2 and the air supply holes 10a, 10a,... Of the bearing sleeve 10 of the upper radial air bearing 3, respectively. A second annular passage 11 and a third annular passage 12 communicating with the air supply holes 10a, 10a,... Of the bearing sleeve 10 of the lower radial air bearing 3 are provided, and the air supply port 1a is connected to the first annular passage 11a. First and second air supply passages 13 and 14 are formed in the passage 9 and communicate with the second and third annular passages 11 and 12, respectively. On the other hand, an exhaust passage 15 for guiding the air discharged from the thrust air bearing 2 and the radial air bearings 3 and 3 communicates with the exhaust port 1b.
[0024]
A chuck 4 a that holds a drill t as a rotary tool on the base end side of the shaft is provided at the lower end of the rotating shaft 4. On the other hand, at the upper end of the housing 1, an opening / closing mechanism 16 that opens and closes the chuck 4 a when supplied with air is provided. The opening / closing mechanism 16 includes a cylinder 17 joined to the upper end surface of the housing 1 with an opening facing downward, a piston 18 slidably inserted into the cylinder 17 in the vertical direction, and the piston A rod 19 integrally provided so as to protrude downward on the lower surface side of 18, and is interposed between the rod 19 and the housing 1, and always urges the rod 19 upward. And a compression coil spring 20 is provided. When air is supplied to the air supply port 17a provided at the center of the bottom of the cylinder 17, the piston 18 pushes down the rod 19 against the urging force of the compression coil spring 20, thereby the chuck 4a. To open.
[0025]
An annular water-cooling jacket 21 is formed on the outer peripheral side of the electric motor 5 of the housing 1 to suppress heat generated by the operation of the motor 5, and water supplied to the water inlet 22 a of the housing 1 is supplied to the jacket 1. 21 is discharged from the drain port 22b.
[0026]
In the present embodiment, the first cover 23 provided to cover the lower end portion of the housing 1 so as to cover the lower end portion and to form an annular gap 23a around the lower end portion of the rotary shaft 4, and the thrust An air passage 24 is provided as a gas passage through which air discharged from the air bearing 2 and the radial air bearings 3 and 3 to the exhaust port 1 b is introduced into the first cover 23. Furthermore, the dust cover is provided so as to overlap the first cover 23, has an opening 25 a through which the shaft portion of the drill t can be inserted, and dust exhaust as an intake means for sucking air discharged from the first cover 23. A second cover having an exhaust port 25b connectable to the blower S is provided.
[0027]
Specifically, the first cover 23 has a bottomed cylindrical shape having the same outer diameter as the housing 1 and the same height as the projecting dimension of the rotary shaft 4 from the housing 1, The upper end surface of the peripheral wall is joined to the lower end surface of the housing 1 in an airtight manner. An opening having a diameter larger than that of the rotating shaft 4 is provided at the center of the bottom wall, and the gap 23a is formed with a predetermined clearance in the radial direction between the opening edge and the rotating shaft 4. Is formed. An inlet 23 b for connecting the downstream end of the air passage 24 is provided on the side peripheral wall of the first cover 23.
[0028]
On the other hand, the second cover 25 also has a bottomed cylindrical shape that is substantially the same size as the first cover 23 and is airtightly joined to the bottom wall of the first cover 23 at the upper end surface of the side peripheral wall thereof. Yes. The opening 25a is provided in the center of the bottom wall, and the exhaust port 25b is provided in the side peripheral wall.
[0029]
Here, the operation of the spindle A configured as described above will be described.
[0030]
Air discharged from the thrust air bearing 2 and the radial air bearings 3 and 3 of the spindle A is introduced into the first cover 23 via the air passage 24. And the air in the 1st cover 23 is discharged outside from the annular clearance 23a around the front-end | tip part of the rotating shaft 4. FIG. At this time, since the lower end portion of the rotating shaft 4 is cooled by the air discharged from the gap 23a, the drill t attached to the rotating shaft 4 is also cooled as a result.
[0031]
Next, the air discharged from the first cover 23 is introduced into the second cover 25 and discharged to the outside from the exhaust port 25 b of the second cover 25 by the dust blower S. Thereby, since the discharge of air from the gap 23a is smoothed, the cooling effect on the drill t is increased accordingly. In addition, scattering of chips as dust resulting from the discharge of air from the first cover 23 is prevented.
[0032]
Therefore, according to the present embodiment, in the spindle A having the thrust air bearing 2 and the radial air bearings 3 and 3, the lower end portion of the housing 1 is covered with the lower end portion and is annular around the lower end portion of the rotating shaft 4. The first cover 23 provided so as to form the gap 23a and the air passage 24 for introducing the air discharged from the air bearings 2 and 3 into the first cover 23 are provided. The drill t can be cooled using the air exhausted from the air bearings 2 and 3, and the life of the drill t can be extended.
[0033]
Further, since the second cover 25 is provided so as to overlap the first cover 23 and the air in the second cover 25 is sucked by the dust blower S, the gap between the first cover 23 and the rotary shaft 4 is provided. The discharge of air from 23a can be facilitated to enhance the cooling effect on the drill t, and scattering of chips around the discharge of the air can be prevented.
[0034]
In addition, although the said Embodiment 1 demonstrated the case where the drill t was attached, you may make it attach another rotary tool.
[0035]
In the first embodiment, all of the air discharged from the air bearings 2 and 3 is introduced into the first cover 23, but the amount of introduction is appropriately set according to the cooling effect on the rotary tool. be able to.
[0036]
Furthermore, in the first embodiment, the first and second covers 23 and 25 are provided. However, for example, when a sufficient cooling effect can be obtained only by the first cover 23, the second cover is provided. 25 may be omitted.
[0037]
(Embodiment 2)
FIG. 2 shows the overall configuration of the spindle A according to the second embodiment of the present invention, and the same parts as those in the first embodiment are denoted by the same reference numerals.
[0038]
In the present embodiment, the first cover 23 is provided so as to form an annular gap 23 a around the shaft portion of the drill t attached to the lower end portion of the rotating shaft 4. That is, the height dimension of the first cover 23 is larger than that in the first embodiment. An opening having a diameter larger than that of the shaft portion of the drill t is provided in the center of the bottom wall, and a predetermined clearance is provided between the opening edge and the shaft portion of the drill t in the radial direction. The gap 23a is formed. Since other parts are the same as those in the first embodiment, description thereof is omitted.
[0039]
Next, the operation of the spindle A configured as described above will be described.
[0040]
Air discharged from the thrust air bearing 2 and the radial air bearings 3 and 3 of the spindle A is introduced into the first cover 23 via the air passage 24. And the air in the 1st cover 23 is discharged outside from the cyclic | annular clearance gap 23a around the axial part of the drill t. At this time, since the shaft portion of the drill t is cooled by the air discharged from the gap 23a, the cooling effect on the drill t is higher than that in the first embodiment. Moreover, since the said air is discharged from the axial part periphery of the drill t, the removal of the chip generated accompanying the process by the drill t is also performed.
[0041]
The air discharged from the gap 23a is introduced into the second cover 25 and discharged to the outside from the exhaust port 25b of the second cover 25 by the dust blower S. Thereby, since the discharge of the air is smoothed, the cooling effect on the drill t is increased accordingly. Further, since the chips removed by the air discharge are sucked by the dust blower S together with the air, the chips are prevented from being scattered around.
[0042]
Therefore, according to the present embodiment, the first cover 23 covers not only the lower end portion of the rotary shaft 4 but also the shaft portion of the drill t, and air is discharged from the gap 23a between the first cover 23 and the shaft portion. Therefore, not only can the drill t be cooled more efficiently than in the case of the first embodiment, but also the chips generated with the machining by the drill t can be removed.
[0043]
Further, since the second cover 25 is provided so as to overlap the first cover 23, and the air in the second cover 25 is sucked by the dust blower S, the gap 23a between the first cover 23 and the drill t is provided. As a result, the air can be smoothly discharged and the cooling effect on the drill t can be enhanced, and the removed chips can be prevented from being scattered around.
[0044]
【The invention's effect】
As described above, according to the first aspect of the present invention, the housing is provided with the rotary shaft rotatably supported via the static pressure gas bearing, and the rotary tool is attached to one end of the rotary shaft. in spindle attached to rotate integrally with the provided near the site of the rotating shaft end of the housing, and a cover forming an annular gap around the one end portion of the not and the rotary shaft covering the site, the externally pressurized gas bearing the gas discharged from it and a gas passage for introducing into the cover, it is possible to cool the rotary tool utilizing exhaust from the externally pressurized gas bearing, possible to extend the life of the rotary tool Can do.
[0045]
According to the invention of claim 2, after the aforementioned cover and the first cover is provided in a state above the Tsu Do heavy in the first cover, with the shaft portion of the rotary tool having an insertion opening capable, by providing the second cover having a possible outlet connected to the intake means for sucking the gas discharged from the gap between the first cover and the rotating shaft end portion, it is possible to further enhance the cooling effect on the rotating tool According to the invention of claim 3, the spindle is provided in the vicinity of one end of the rotating shaft in the housing, and the dust can be prevented from being scattered around due to gas discharge from the gap. a cover forming an annular gap around the shaft portion of the rotary tool attached to have and the rotation shaft one end covering the site, and the gas passage a gas discharged from the externally pressurized gas bearing is introduced into the cover Since it was decided to include the not only can be cooled efficiently rotary tool than the invention described in claim 1, removing the dust such as chips generated with the processing by the rotary tool Can do.
[0046]
According to the invention of claim 4, after the above covering the first cover, provided in a state above the Tsu Do heavy in the first cover, with the shaft portion of the rotary tool having an insertion opening capable, since it was decided to include a second cover having a possible outlet connected to the intake means for sucking the gas discharged from the gap between the first cover and the rotating tool shaft, it is possible to further enhance the cooling effect on the rotating tool In addition, it is possible to prevent the dust removed by the gas discharge from being scattered to the surroundings. [Brief description of the drawings]
FIG. 1 is a longitudinal sectional view showing an overall configuration of a spindle according to Embodiment 1 of the present invention.
FIG. 2 is a view corresponding to FIG. 1 showing an overall configuration of a spindle according to Embodiment 2 of the present invention.
[Explanation of symbols]
1 Housing 2 Thrust air bearing (hydrostatic gas bearing)
3 Radial air bearing (hydrostatic gas bearing)
4 Rotating shaft 23 First cover 23a Clearance 24 Air passage (gas passage)
25 Second cover 25a Opening 25b Exhaust port A Spindle t Drill (Rotary tool)
F Air supply device (gas supply source)
S Dust exhaust blower (air supply means)

Claims (4)

A rotary shaft supported rotatably on the housing via a hydrostatic gas bearing, the rotary shaft having an end portion to which the rotary tool is integrally attached at the shaft end portion of the rotary tool; in supplied with gas from the source to operate the externally pressurized gas bearing away spindles,
Provided near the site of the rotating shaft end of the housing, and Luca bar to form an annular gap around the one end portion of the and rotary shaft portion near yet covered,
A spindle comprising: a gas passage that introduces gas discharged from the static pressure gas bearing into the cover. The spindle according to claim 1, wherein
The cover is a first cover;
Provided state Tsu Do heavy in the first cover, with the shaft portion of the rotary tool having an insertion opening capable, inlet means for sucking the gas discharged from the gap between the first cover and the rotating shaft end portion And a second cover having an exhaust port connectable to the spindle. A rotary shaft supported rotatably on the housing via a hydrostatic gas bearing, the rotary shaft having an end portion to which the rotary tool is integrally attached at the shaft end portion of the rotary tool; in supplied with gas from the source to operate the externally pressurized gas bearing away spindles,
Provided near the site of the rotating shaft end of the housing, and Luca bar to form an annular gap around the shaft portion of the rotary tool attached to have and the rotation shaft one end covering the portion near,
A spindle comprising: a gas passage that introduces gas discharged from the static pressure gas bearing into the cover. The spindle according to claim 3, wherein
The cover is a first cover;
Provided state Tsu Do heavy in the first cover, while the shaft portion of the rotary tool having an insertion opening capable, inlet means for sucking the gas discharged from the gap between the first cover and the rotating tool shaft And a second cover having an exhaust port connectable to the spindle.

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