JP6623720B2 - Spindle device - Google Patents

Description

  The present invention relates to a spindle device, and more particularly, to a spindle device that can be suitably used for an electrostatic coating machine.

  Conventionally, as a spindle device used in an electrostatic coating machine, one shown in FIG. 4 is known (for example, see Patent Document 1). This spindle device 100 has a bell cup 101 at one axial end. A rotating shaft 103 provided with a plurality of turbine blades 102 at the other end in the axial direction, a housing 104 through which the rotating shaft 103 is inserted, and a device case 105 for housing the housing 104 are provided. By ejecting gas to the turbine blade 102, the rotating shaft 103 is rotated.

  The rotating shaft 103 is rotatably supported in a radial direction by a gas bearing 106 attached to the housing 104. Further, the rotating shaft 103 is supported in the thrust direction by a balance between a magnetic force for attracting the flange portion 108 by the magnet 107 attached to the housing 104 and a reaction force when blowing gas to the flange portion 108 by the gas bearing 106. I have.

JP 2006-77797 A

  By the way, in the spindle device 100 as shown in FIG. 4, the turbine blade 102 and the gas bearing 106 are arranged apart from each other in the axial direction, and have a configuration that is long in the axial direction. For this reason, there are problems such as an increase in overall weight, a large moment load applied to the gas bearing 106 due to the rotation of the turbine blade 102, and a long gas supply passage, and further improvements are required.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a spindle device that has a flat configuration with a short axial length and can be reduced in size and weight.

The above object of the present invention is achieved by the following configurations.
(1) a rotating shaft on which a plurality of turbine blades are provided in a circumferential direction;
A housing for accommodating the rotating shaft;
A gas bearing attached to the housing and supporting the rotary shaft in a floating manner in a non-contact manner with respect to the housing by supplying gas.
A spindle device that rotationally drives the rotating shaft by ejecting gas to the plurality of turbine blades,
The spindle device, wherein the plurality of turbine blades are arranged radially inward with respect to the gas bearing, and overlap the gas bearing in the axial direction.
(2) a magnet that attracts the flange provided on the rotating shaft in the axial direction,
The gas bearing blows gas toward the outer peripheral surface of the rotating shaft, and the axial side surface of the flange portion,
The spindle device according to (1), wherein the rotating shaft is supported in a radial direction and a thrust direction with respect to the housing by the magnet and the gas bearing.
(3) The spindle device according to (1) or (2), wherein the gas is supplied to the gas bearing at a plurality of positions in an axial direction.

According to the spindle device of the present invention, the plurality of turbine blades overlap the gas bearing in the axial direction, so that the spindle device can be flattened, and painting in a narrow space due to miniaturization and weight reduction can be achieved. Thus, the robot can be reduced in size. Further, with this configuration, the moment load applied to the gas bearing due to the rotation of the turbine blade can be reduced as compared with the configuration in which the plurality of turbine blades and the gas bearing are separated in the axial direction. Is reduced and the pipe resistance is reduced, so that pressure loss can be suppressed.
Further, since the plurality of turbine blades are arranged radially inward with respect to the gas bearing, the moment of inertia during rotation of the rotating shaft is reduced, and the time required for acceleration and deceleration can be reduced.

It is a sectional view of the spindle device concerning a 1st embodiment of the present invention. FIG. 3 is a schematic sectional view of a housing and a rotation shaft for explaining a turbine blade and a nozzle. It is a sectional view of a spindle device concerning a 2nd embodiment of the present invention. It is sectional drawing of the conventional spindle device.

  Hereinafter, embodiments of a spindle device according to the present invention will be described in detail with reference to the drawings. In the following description, the left side shown in FIG. 1 is referred to as a front side, and the right side is referred to as a rear side.

(1st Embodiment)
As shown in FIGS. 1 and 2, the spindle device 10 of the present embodiment is an air turbine driven type spindle device used for an electrostatic coating machine. The spindle device 10 includes a rotating shaft 12 on which a plurality of turbine blades 11 are provided in a circumferential direction, a housing 20 that houses the rotating shaft 12, a gas bearing 40, and a magnet 50. And a radial bearing and a thrust bearing that support the radial direction and the thrust direction with respect to the radial direction.

The rotating shaft 12 has a mounting screw 13 and a tapered surface 14 on the outer peripheral surface, and a work mounting portion 15 to which the bell cup 1 which is a coating jig for spraying paint in the form of a mist is mounted. It has a flange portion 16 extending radially outward from the base end of the mounting portion 15 and a cylindrical portion 17 extending axially from a radially intermediate portion of the flange portion 16 and is formed in a hollow shape. Have been.
The plurality of turbine blades 11 are formed by processing an inner peripheral surface of the cylindrical portion 17.

  The housing 20 has a front housing 21, a rear housing 22, and a front lid 35, and each is formed in a hollow shape. The front housing 21 is located on the outer diameter side of the cylindrical portion 17 of the rotating shaft 12, and the front cover 35 is formed so as to be closely opposed to the front side surface of the flange portion 16. The front lid 35, the front housing 21, and the rear housing 22 are fastened and fixed by bolts (not shown). The rear housing 22 includes an axially extending portion 23 that extends inside the cylindrical portion 17 of the rotating shaft 12 toward the rear surface of the flange portion 16 and is formed to have a substantially L-shaped cross section.

  The gas bearing 40 is a cylindrical porous member, and is attached to the inner peripheral surface of the front housing 21. The gas bearing 40 blows compressed air toward the outer peripheral surface of the cylindrical portion 17 of the rotating shaft 12 by supplying gas from a bearing air supply path 24 formed in the front housing 21 and the rear housing 22, and The floating shaft 12 is levitated and supported in a non-contact manner. Thus, the rotating shaft 12 is supported by the gas bearing 40 in the radial direction with respect to the housing 20.

  The gas bearing 40 has a front end surface in the axial direction facing the rear surface of the flange portion 16 of the rotating shaft 12, and compressed air is blown toward the rear surface of the flange portion 16.

The magnet 50 is held by a magnet yoke 51, and the magnet yoke 51 is screwed and attached to a magnet attachment portion 25 formed inside the axially extending portion 23 of the rear housing 22. In this state, the magnet 50 is closely opposed to the rear side surface of the flange portion 16.
Therefore, the flange portion 16 is pulled rearward by the magnetic force of the magnet 50. On the other hand, the gas bearing 40 generates a reaction force by blowing the compressed air toward the rear side surface (axial side surface) of the flange portion 16, and the rotating shaft is formed by the attractive force of the magnet 50 and the reaction force of the gas bearing 40. 12 is supported in the thrust direction with respect to the housing 20.

  The rear housing 22 includes a turbine air supply path 26 for supplying compressed air for operation to the turbine blade 11, another turbine air supply path 28 for supplying compressed air for brake to the turbine blade 11, Further, a nozzle ring 36 in which a plurality of nozzles 27 are formed is attached to the outer peripheral surface of the axially extending portion 23 of the rear housing 22. As shown in FIG. 2, a plurality of nozzle rings 36 communicate with the turbine air supply path 26 and extend linearly inclining to one side in the circumferential direction with respect to the radial direction (in the present embodiment, in the circumferential direction). (Six at regular intervals) are connected to the forward rotation nozzle 27 and the other turbine air supply path 28, and are formed with a reverse rotation nozzle 29 that extends linearly inclining to the other side in the circumferential direction with respect to the radial direction. I have.

  In the rear housing 22, a turbine air exhaust hole 30 for discharging turbine air and a detection hole 31 for inserting a rotation sensor are formed to penetrate in the axial direction.

  Therefore, in the spindle device 10 configured as described above, by supplying the gas to the gas bearing 40, the plurality of turbines 27 are rotated from the plurality of normal rotation nozzles 27 while the rotation shaft 12 is rotatably supported by the housing 20. By jetting gas toward the blades 11, the kinetic energy of the jet is converted into the rotational driving force of the rotary shaft 12, and the rotary shaft 12 is driven to rotate.

  Here, the spindle device 10 of the present embodiment is configured such that the plurality of turbine blades 11 overlap the gas bearing 40 in the axial direction. Accordingly, the spindle device 10 can be flattened, and painting in a narrow space due to miniaturization and downsizing of the robot can be realized by weight reduction. Further, with this configuration, the moment load applied to the gas bearing 40 due to the rotation of the turbine blade 11 can be reduced as compared with the configuration in which the plurality of turbine blades 11 and the gas bearing 40 are separated in the axial direction. Since the bearing air supply path 24 and the turbine air supply paths 26 and 28 are shortened and the pipe resistance is reduced, pressure loss in the paths can be suppressed.

  Further, since the plurality of turbine blades 11 are arranged radially inward with respect to the gas bearing 40, the moment of inertia during rotation of the rotating shaft 12 is reduced, and the time required for acceleration and deceleration can be reduced.

  Furthermore, by adopting the above configuration, the bearing air supply path 24 ejects air radially inward, and the forward nozzle 27 and the reverse nozzle 29, which are turbine nozzles, direct air radially outward. It becomes the composition which gushes. Therefore, the bearing air supply path 24 passes through the outer side of the turbine air exhaust hole 30 in the radial direction and opens at the rear end surface of the rear housing 22, and the turbine air supply paths 26 and 28 extend in the radial direction of the turbine air exhaust hole 30. It passes through the inside and opens to the rear end face of the rear housing 22, so that the layout of these paths 24, 26 and 28 is increased in the degree of freedom.

  The gas bearing 40 further includes a magnet 50 that attracts the flange portion 16 provided on the rotating shaft 12 in the axial direction. The gas bearing 40 blows gas toward the outer peripheral surface of the rotating shaft 12 and the axial side surface of the flange portion 16, Since the rotating shaft 12 is supported in the radial direction and the thrust direction with respect to the housing 20 by the gas bearing 40 and the magnet 50, the rotating shaft 12 can be compactly supported with respect to the housing 20.

(2nd Embodiment)
Next, a spindle device 10 according to a second embodiment of the present invention will be described.
In the spindle device 10a of the present embodiment, the gas bearing 40a has a longer axial dimension than the gas bearing 40 of the first embodiment. In addition, gas is supplied to the gas bearing 40a at two positions in the axial direction from the opening of the bearing air supply path 24 branched into two, and an exhaust hole 41 penetrating in the radial direction to an intermediate portion in the axial direction. And a bearing air discharge path 32 formed in the rear housing 22 communicates to discharge gas to the outside.

Accordingly, in the spindle device 10a of the present embodiment, the gas bearing 40a supplies gas at a plurality of positions in the axial direction, and the axial dimension of the gas bearing 40a can be lengthened. Therefore, the spindle device 10 can increase the moment rigidity of the spindle device 10a, though the overall axial dimension is longer than that of the first embodiment.
Other configurations and operations are the same as those of the first embodiment.

The present invention is not limited to the above-described embodiments, and can be appropriately modified, improved, and the like.
For example, in the present embodiment, the spindle device of the present invention has been described as being used in an electrostatic coating machine. However, the present invention is not limited to this. It can also be applied to an edge deburring machine.

  Further, the term "a plurality of turbine blades overlaps the gas bearing in the axial direction" in the present invention includes a configuration in which at least a part of the plurality of turbine blades overlaps in the axial direction. That is, as in the present embodiment, both ends of the plurality of turbine blades in the axial direction may overlap with the gas bearing in the axial direction, or at least a part of the plurality of turbine blades in the axial direction may be in the axial direction. May be overlapped.

  Further, in the present embodiment, the rotary shaft 12 is supported in the radial direction and the thrust direction using the gas bearing and the magnet, but the rotary shaft 12 is supported in the radial direction and the thrust direction using the plurality of gas bearings. The configuration may be as follows.

  Further, the gas bearing of the present invention is not limited to the one formed of a porous member, but may be another static pressure type such as a self-contained throttle. However, a gas bearing using a porous member can easily secure rigidity, and therefore can secure sufficient rigidity even when the gas flow rate is small.

DESCRIPTION OF SYMBOLS 10 Spindle device 11 Turbine blade 12 Rotary shaft 16 Flange part 20 Housing 40 Gas bearing 50 Magnet

Claims (3)

A rotating shaft in which a plurality of turbine blades are provided on the inner peripheral surface in a circumferential direction;
A housing for accommodating the rotating shaft;
A gas bearing attached to the housing and supporting the rotary shaft in a floating manner in a non-contact manner with respect to the housing by supplying gas.
A spindle device that rotationally drives the rotating shaft by ejecting gas to the plurality of turbine blades,
The spindle device, wherein the plurality of turbine blades are arranged radially inward with respect to the gas bearing, and overlap the gas bearing in the axial direction. Further comprising a magnet that attracts the flange portion provided on the rotating shaft in the axial direction,
The gas bearing blows gas toward the outer peripheral surface of the rotating shaft, and the axial side surface of the flange portion,
The spindle device according to claim 1, wherein the rotating shaft is supported by the magnet and the gas bearing in a radial direction and a thrust direction with respect to the housing.   The spindle device according to claim 1, wherein the gas bearing is supplied with gas at a plurality of positions in an axial direction.

Images