JP2003278751A - Spindle device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a spindle device wherein allowance of unbalance is improved, weigh the device is saved on, and of maintainability is improved. <P>SOLUTION: This spindle device is furnished with a rotation axis 1 having a head mounting part 1a on which an atomizing head 11 is mounted and a radial bearing 4 and a thrust bearing 5 to support the rotation axis 1 against a housing 2 free to rotate. The radial bearing 4 and the thrust bearing 5 are made into foil bearings. These foil bearings have bearing foils 23, 56 respectively having bearing surfaces to face the rotation axis 1 and elastic bodies 22, 53 to support the bearing foils 23, 56. The elastic bodies 22, 53 are, for example, made into an aggregate of metal fine lines. The radial bearing 4 and the thrust bearing 5 are respectively utilized with bearing housings 21, 51 and detachably mounted on a main body bearing housing 10. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spindle device in which an atomizing head is attached to a rotary shaft, for example, a high speed spindle device used in a rotary atomizer for atomizing a liquid by centrifugal force.

[0002]

2. Description of the Related Art A rotary atomizer, which supplies liquid to a disk-shaped spraying head that rotates at high speed and atomizes the liquid by centrifugal force, is a rotary atomizing electrostatic coating machine that atomizes paint, a powder manufacturing apparatus, It is used in spray dryers. The powder production apparatus is an apparatus for obtaining fine particles by atomizing molten metal or the like in an inert gas atmosphere and quenching. The spray dryer is for producing a powder by atomizing a solution of food or medicine in hot air. Hereinafter, the rotary atomization type electrostatic coating machine will be described as an example. In a rotary atomizing electrostatic coating machine, a rotating shaft having an atomizing head attached to its tip is rotated at high speed, and the paint is supplied to the atomizing head to atomize the paint by centrifugal force. Initially, rolling bearings were used as the bearings that support the rotating shaft.However, in order to solve the problems of life due to high speed rotation in solvent atmosphere and the problem of paint contamination due to leaked lubricating oil, air bearings have been used. The one to be used has been proposed and put into practical use.

Examples of spindle devices for electrostatic coating using air bearings are shown in FIGS. The example of FIG. 6 is an example (Japanese Patent Laid-Open No. 9-173913) to which a hydrostatic air bearing that supplies pressurized air from the outside is applied. In the inner hole 61a of the housing 61, a rotating shaft 67 and a turbine rotor 68 for generating a rotating force, which is provided at a rear end portion of the rotating shaft, are installed in the bearing gap 6a.
It is inserted through 6. A radial air bearing 69 is formed between the periphery of the rotary shaft 67 and the air supply nozzle 64, and a thrust air bearing 70 is formed between the rotor 68 and the air supply nozzle 65. When compressed air is supplied from the air supply nozzles 64 and 65 to the bearing gap,
The rotating shaft 67 and the rotor 68 are levitationally supported by the pressure of the air, and are brought into a non-contact state with the housing 61, and the radial air bearing 69 and the thrust air bearing 70.
The function of the static pressure air bearing consisting of is demonstrated. On the other hand, a plurality of turbine blades 79 are arranged around the rotor 68 at the rear end of the rotating shaft 67, and a compressed air ejection hole 80 for blowing out compressed air to the turbine blades 79 is formed in the housing 61 in a substantially tangential direction. ing. Further, a compressor 81 is connected to the ejection hole 80. In this structure, when compressed air is blown from the compressor 81 to the turbine blade 79 through the ejection hole 80, a rotational force is applied to the turbine blade 79, and as a result, the levitationally supported rotating shaft 67 is rotated at a high speed. A paint spraying head 73 is attached to the front end of the rotary shaft 67.
The paint sprayed from the spray nozzle 77 is the spray head 73.
Is rotated at a high speed to be introduced into the inner peripheral surface of the cup-shaped guide plate 74 through the outflow hole 78, and is blown to the surroundings while being atomized by centrifugal force. In this case, when the spray head 73 is in a charged state, the coating material is charged with a negative charge while flowing through the inner peripheral surface thereof, and is attracted to the grounded object by electrostatic force.

FIG. 7 shows an example in which a tilting pad type dynamic air journal bearing is used as a radial air bearing (Japanese Patent Laid-Open No. 56-16775). FIG. 8 is a sectional view of the tilting pad type dynamic pressure air journal bearing. The spindle of FIG. 7 comprises a substantially hollow cylindrical front housing 102 and a rear housing 103, which are connected by bolts 104. Rotating shaft 108
Is inserted into the front housing 102, and a paint spraying head 109 is attached to the front end of the front housing 102 by a nut 110. The front housing 102 is provided with two tilting pad air bearings 122 and 123, and
Support. The tilting pad air bearing has three pads 12 arranged with a slight clearance from the outer peripheral surface of the hollow cylindrical portion 108a of the rotating shaft, as shown in the cross section of FIG.
It is equipped with 4,125,126. These pads are swingably supported by support pins 127, 128 and 129, respectively. The support pin 127 is fixed via a support arm having a leaf spring portion 136a, and the pad 124 is pressed against the rotary shaft hollow cylindrical portion 108a by the force of the leaf spring portion 136a. When the rotary shaft 108 rotates, ambient air causes the rotary shaft hollow cylindrical portion 108a and the pads 124, 1
25, 126 is drawn into the gap and a pressure is generated by the so-called dynamic pressure effect. Pads 124, 125, 12
Since 6 is swingable and the pad 124 is elastically supported in the radial direction, whirling of the rotating shaft 108 due to imbalance and aerodynamic instability is effectively suppressed, and stable even at high speed rotation. The rotating shaft 108 can be supported.

For the axial support of the rotary shaft 108, a hydrostatic air bearing is used in this example as well. A pair of disc-shaped runners 139, 14 are attached to the shaft portion 108c of the rotating shaft 108 of FIG.
0 and the turbine impeller 142 are fixed. Compressed air outflow holes 151, 1 are provided between the runners 139, 140.
The annular plates 144 provided with 52 are arranged with a slight gap therebetween to form a hydrostatic air thrust bearing. From the jet nozzle 157 of compressed air, compressed air is supplied to the turbine impeller 1
The rotary shaft 108 is rotated by ejecting the rotary shaft 108 toward 42. In the case of an electrostatic coating machine, a high voltage is applied, so it is often driven by an air turbine in order to ensure the insulation of the spindle.However, in rotary atomizers for other applications, an electric motor is used as the rotation drive means. Some use.

[0006] Japanese Patent Laid-Open Publication No. Sho 56-56, which shows an example of FIG.
163775), in the "Detailed Description of the Invention", "Foil bearings are also suitable for use on rotating shafts that rotate at high speeds, and therefore foil bearings are used instead of the tilting pad air bearings 122, 123. Can also be used. " No further specific details are disclosed.

In the foil bearing, the bearing surface is made of a flexible thin metal plate, and a pressure is generated between the metal plate and the rotary shaft due to the dynamic pressure effect accompanying the rotation of the rotary shaft, so that the rotary shaft does not contact. It is a type of dynamic pressure air bearing supported by. Various types of foil bearings have been conventionally proposed. Among them, the main ones are shown in FIGS. 9 (A) to (C). Figure 9
The foil bearing of (A) is a rotatable support roller 201.
Are provided at three locations, and when the rotary shaft 202 is stationary by applying tension to the endless annular foil 203, the foil 203 comes into contact with the outer circumference of the rotary shaft 202 at three locations. According to Japanese Patent Laid-Open No. 54-87343, which discloses the main foil bearing, the foil rotates together with the rotating shaft until the rotational speed of the rotating shaft increases and sufficient pressure is generated. It has no wear and has a long life.

In the foil bearing shown in FIG. 9B, the bearing surface is made up of a large number of thin plates 303, and pressure is generated by a dynamic pressure effect at a large number of positions on the outer circumference of a rotary shaft (not shown). Figure 9
In the foil bearing of (C), the top foil 405 makes almost one round around the rotary shaft 401 with a gap A, and the bump foil includes the housing 402 and the top foil 40.
5, supporting the top foil 405. Foil bearings are widely applied to turbomachines such as gas turbines and compressors because their structure allows for thermal deformation and assembly error.

[0009]

In the rotary atomizer, it is necessary to frequently replace the atomizing head, but the imbalance tends to increase due to wear of the attachment portion of the atomizing head and the rotary shaft and deformation of the atomizing head. Is. Further, the imbalance becomes large when the liquid to be treated is nonuniformly adhered or is solidified in that state. For this reason, the rotary atomizer spindle must endure a large imbalance and rotate at high speed. Further, in order to process a highly viscous liquid or to reduce the diameter of particles, it is necessary to increase the speed of the spindle. However, in the conventional spindle shown in FIG. 6 and FIG. It may not be able to withstand, and the rotating shaft and the bearing surface may come into contact with each other and become unable to rotate.

In the case of an electrostatic coating machine, recently, a coating head including a spindle is often mounted on an articulated robot to perform coating work. In this case, if the spindle is heavy, a large robot is required, which causes a problem in terms of installation area and cost. Therefore, it is necessary to reduce the weight of the spindle device. Since the bearing gap of the hydrostatic air bearing is determined by the dimensional difference of each component forming the bearing, it is necessary to perform machining with extremely high accuracy. Therefore, it is necessary to increase the rigidity of the parts and minimize the deformation during processing. Furthermore, it is necessary to provide an air supply passage to the bearing inside the housing. For these reasons, it is difficult to reduce the wall thickness of the parts to reduce the weight. In addition to the impossibility of rotation due to the contact between the rotating shaft and bearing surface,
The liquid to be processed may enter the spindle and become unrotatable. In these cases, in the conventional spindle device, the non-rotatable rotary shaft must be removed from the device and returned to the manufacturer for repair. Therefore, the repair requires a great deal of expense and time. In addition, it is necessary to prepare a spare spindle to operate the line during repair, which is also expensive in this respect.

In the case of the spindle using the tilting pad bearing shown in FIG. 7, in order to obtain a predetermined floating characteristic, the radius of curvature of the bearing surface of the bearing pad is several degrees with respect to the outer diameter of the rotating shaft. It is necessary to increase it by about 10 μm,
In addition, the bearing pads are partially arcuate, making them more difficult to machine than hydrostatic bearings. Further, since the thrust bearing is a hydrostatic air bearing, the runners 139 and 140 fixed to the rotary shaft maintain a predetermined thrust bearing clearance with respect to the thrust bearing surface (both sides of the annular plate 144) fixed to the housing. It is necessary to adjust the position of the pads of the radial bearing so that they are placed in position. As described above, processing and assembling adjustment are extremely difficult and mass productivity is poor, so this type has not been used in an actual painting line.

An object of the present invention is to provide a spindle device capable of improving the allowable unbalance amount and reducing the weight of the device. Another object of the present invention is to improve maintainability.

[0013]

A spindle device according to the present invention comprises a rotary shaft having a head mounting portion to which an atomizing head is mounted, a radial bearing and a thrust bearing for rotatably supporting the rotary shaft with respect to a housing. In a provided spindle device, each of the radial bearing and the thrust bearing has a bearing foil having a bearing surface facing the rotation shaft, and an elastic body elastically supporting the bearing foil between the housing and the bearing foil. It is characterized by using a foil bearing. In the foil bearing in which the bearing foil is thus supported by the elastic body, when the rotating shaft swings, the bearing foil moves accordingly, and relative movement occurs between the bearing foil and the elastic body and between the elastic body and the housing. The frictional force at this time acts as a damping force against the whirling of the rotating shaft. Therefore, a very large damping force can be obtained as compared with the damping force due to the viscosity of the air in the bearing gap as in a static pressure air bearing. Since the foil bearing having such an action is used for both the radial bearing and the thrust bearing for supporting the rotating shaft, the allowable unbalance amount can be improved. For this reason, even if the atomizing head is deformed or the treatment liquid or its solidified substance is attached on one side, it can rotate normally. Further, when the radial bearing and the thrust bearing are foil bearings, each bearing surface can be deformed, so that some shape errors and assembly errors can be absorbed, and part precision can be relaxed. As a result, not only the manufacturing cost can be reduced, but also the parts can be thinned to reduce the weight and size of the spindle device.

This spindle device includes, for example, a plurality of the radial bearings, the rotary shaft has a thrust plate,
As the thrust bearing, a pair of thrust bearings facing each other on both sides of the thrust plate are provided.

In the spindle device according to the present invention, at least one of the radial bearing and the foil bearing serving as the thrust bearing may be configured such that the elastic body forming the foil bearing is formed of an assembly of fine metal wires. When the elastic body is composed of thin metal wires, the thin metal wires also rub against each other, so that a larger damping force is generated than when the elastic body is composed of a thin metal plate.

In the radial bearing composed of the foil bearing, the bearing foil and the elastic body are coupled to each other, and the elastic body is elastically deformed and incorporated into the inner diameter surface of the housing, and the elastic body and the bearing foil are formed of the elastic body. It may be fixed to the inner diameter surface of the housing by elastic restoring force. When the structure is fixed by the elastic restoring force of the elastic body as described above, it is fixed by the frictional force. Therefore, when the rotating shaft and the bearing foil come into contact with each other during high-speed rotation and excessive torque is generated. The bearing foil and the elastic body rotate together with the rotating shaft, and damage to the rotating shaft can be suppressed to a small level.

A spindle device according to the present invention comprises a plurality of the radial bearings, a housing for supporting the elastic body of each radial bearing and a bearing foil, and a main body housing to which the bearing housing is detachably mounted. It may be divided into. That is, each radial bearing is a bearing unit including a foil bearing and a bearing housing. Thus, if each radial bearing is individually unitized and attached to the housing body, the bearing unit can be attached and detached when the bearing is damaged, and the repair is easy. In the case of the split structure, there is a problem in assembling accuracy, but since the foil bearing can absorb some assembling error, such splitting can be realized.

In the case of unitizing in this way, the main body housing is further divided into an outer case and a split housing detachably attached to the outer case and bearing housings of a plurality of radial bearings are detachably attached. It may be good. This makes repairs easier.

The spindle device of the present invention is a spindle device comprising a rotary shaft having a head mounting portion to which an atomizing head is mounted, and a radial bearing rotatably supporting the rotary shaft with respect to a housing. The bearing is a bearing foil having a bearing surface facing the rotating shaft, and a foil bearing having an elastic body that elastically supports the bearing foil between the housing and the bearing foil, and the elastic body is an assembly of thin metal wires. It may be

The spindle device of the present invention is a spindle device for a rotary atomizer, wherein the atomizing head atomizes the liquid by centrifugal force, and the rotary shaft is a hollow shaft. A nozzle for supplying a liquid for atomization to the atomizing head is inserted into the rotary shaft, a turbine blade is provided on the outer periphery of the rotary shaft, and a turbine nozzle for blowing a compressed gas to the turbine blade is provided in the housing. It may be the one that was given. In a spindle device for a rotary atomizer, there is a large problem that a vibrating force is generated due to wear and deformation of the mounting portion of the atomizing head and imbalance due to adhesion of the processing liquid, and improvement of the allowable imbalance amount is strongly demanded. The above-mentioned configurations of the present invention can meet such demands.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described with reference to the drawings. This embodiment is an example applied to a rotary atomizer spindle device for electrostatic coating. In FIG.
In this spindle device, a rotary shaft 1 is rotatably supported by a radial bearing 4 and a thrust bearing 5 with respect to a housing 2, and the radial bearing 4 and the thrust bearing 5 are foil bearings. This spindle device
A drive mechanism 19 for rotating the rotary shaft 1 is provided. The rotary shaft 1 is a hollow shaft, and a paint injection nozzle 12 is arranged in the hollow portion. An atomizing head mounting portion 1a is formed at the tip of the rotary shaft 1, and the atomizing head 11 is detachably fixed. A disk-shaped thrust plate 3 is provided at the rear end of the rotary shaft 1. A large number of recesses are provided on the outer peripheral surface of the thrust plate 3 at equal intervals, and turbine blades 18 are formed between adjacent recesses. This turbine blade 18
And the turbine nozzle 7 provided in the housing 10,
The drive mechanism 19 is configured.

The rotary shaft 1 is supported by two radial bearings 4 lined up in the axial direction and two thrust bearings 5 facing each other on both sides of the thrust plate 3. The housing 2 is divided into a bearing housing 21, 51 provided for each of the radial bearing 4 and the thrust bearing 5, and a main body housing 10 to which the bearing housing 21, 51 is detachably attached. The body housing 10 is
Further, the external case 10A and the front and rear split housings 14 and 15 detachably attached to the external case 10A.
It is divided into and. One of the two radial bearings 4 and the thrust bearing 5 is fixed to the front split housing 14. The other thrust bearing 5 is fixed to the rear split housing 15. The front split housing 14 and the rear split housing 15 are integrally fixed by a bolt (not shown) via a spacer 16.

The nozzle sleeve 6 is fixed to the inner peripheral side of the spacer 16. The inner circumference of the nozzle sleeve 6 faces the outer circumference of the thrust plate 3, and the turbine nozzle 7 is provided substantially tangentially. The turbine nozzle 7 is connected to a compressed air source (not shown) via an annular air supply passage 8 and an air supply passage 9 provided on the outer circumference of the nozzle sleeve 6 and the inner circumference of the spacer 16. When the compressed air is supplied from the compressed air source, the compressed air is ejected from the turbine nozzle 7 in a substantially tangential direction and collides with the turbine blade 18 on the outer periphery of the thrust plate 3 to generate a driving force for rotating the rotary shaft 1. Then, the compressed air is transferred to the outer case 10
It flows out through the exhaust passage (not shown) provided in A.

A rotation mark flange 17 is provided on the outer peripheral portion of the thrust plate 3. The rotation sensor 13 faces the rotation mark flange 17, detects a rotation mark provided on the rotation mark flange 17, and detects the number of rotations. The rotation mark can be provided by a method such as coloring, magnetization, and unevenness of the surface shape. As the rotation sensor 13, a photoelectric switch, a magnetic sensor, an electromagnetic pickup, a displacement meter, or the like can be used according to the mark. Non-contact sensors are desirable because they rotate at high speeds.

The structure of the radial bearing 4 is shown in FIG. The elastic body 22 and the bearing foil 23 are arranged on the inner diameter side of the bearing housing 21, and the inner peripheral surface of the bearing foil 23 faces the outer peripheral surface of the rotary shaft 1. The bearing housing 21 is a cylindrical member. The elastic body 22 is a so-called bump foil obtained by bending a thin metal plate into a corrugated plate shape, and is between the bearing housing 21 and the bearing foil 23, and elastically supports the bearing foil 23. The bearing foil 23 and the elastic body 22 are formed in a rectangular ribbon shape,
The respective ends are overlapped and joined together by a method such as welding or caulking. The bearing foil 23 and the elastic body 22 which are integrally connected are rolled into a cylindrical shape and placed in the bearing housing 21. The bearing foil 23 and the elastic body 22 are, due to the frictional force generated by the elastic restoring force of themselves,
It is fixed to the inner diameter surface of the bearing housing 21. When the rotary shaft 1 rotates in the direction of the arrow in FIG. 2, ambient air is drawn between the bearing foil 23 and the rotary shaft 1 to generate pressure,
The rotary shaft 1 is supported in non-contact with the bearing foil 23. The radial bearing 4 and the bearing housing 21 constitute a bearing unit 4A.

FIG. 3 shows another structural example of the radial bearing 4. The elastic body 32 and the bearing foil 33 are arranged on the inner diameter side of the bearing housing 21, and the inner peripheral surface of the bearing foil 33 faces the outer peripheral surface of the rotary shaft 1. When the rotary shaft 1 rotates in the direction of the arrow in FIG. 3, the rotary shaft 1 operates in the same manner as in the example of FIG. 2 and supports the rotary shaft 1 in a non-contact manner. The elastic body 32 is an assembly of fine metal wires, and is manufactured by knitting fine metal wires into a predetermined shape. For example, the elastic body 32 is formed in a rectangular shape. The rectangular elastic body 32 and the ribbon-shaped bearing foil 33 are integrally fixed at one end by a method such as welding or caulking, and are rolled into a cylindrical shape and placed in the bearing housing 21. Elastic body 32 and bearing foil 3
3 is fixed to the inner diameter surface of the bearing housing 21 by the frictional force generated by the elastic restoring force of the elastic body 32 and the bearing foil 33. Instead of rounding the elastic body 32 into a rectangular shape as described above, the elastic body 32 may be formed into a cylindrical shape and press-fitted into the inner diameter surface of the bearing housing 21. The radial bearing 4 and the bearing housing 21 constitute a bearing unit 4A.

The radial bearing 4 constructed as shown in FIG. 2 or 3 is inserted into the bearing fitting portion formed on the inner diameter surface of the front split housing 14 in the state of the bearing unit 4A, and is set by the set screw 29. It is fixed in a detachable state.

FIG. 4 shows another fixing structure of the radial bearing 4. In this case, an axial groove 42 is provided on the inner diameter surface of the front split housing 14, and a leaf spring 43 having a convex portion 44 at the tip is fixed inside the groove 42. A circumferential groove 46 is provided on the outer circumference of the bearing housing 21, and the convex portion 44 engages with the circumferential groove 46, whereby the radial bearing 4 is fixed to the front split housing 14.

The structure of the thrust bearing 5 of FIG. 1 is shown in FIG. The thrust bearing 5 has a bearing foil 56 and an elastic body 53. The elastic body 53 is formed by knitting fine metal wires into a ring shape, and has convex portions 5 at equal intervals in the circumferential direction.
Have 4. The elastic body 53 is the groove 5 of the bearing housing 51.
Incorporated in 2. The bearing foil 56 is formed by arranging a plurality of divided bearing foils 56a formed in an arc shape in an annular shape, and each divided bearing foil 56a is fixed to a ring-shaped foil base 55 by welding or brazing. . The foil base 55 is provided with a plurality of holes 55a corresponding to the respective convex portions 54 of the elastic body 53 arranged side by side in the circumferential direction, and the bearing foil 56 has the convex portions 5 protruding from the holes.
It is elastically supported by 4. The bearing housing 51, the elastic body 53, and the foil base 55 to which the bearing foil 56 is fixed are overlapped with each other, and are integrally fixed with the screw 57 to form the bearing unit 5A of the thrust bearing 5. The bearing foil 56 faces the end surface of the thrust plate 3 of the rotary shaft 1 in FIG.

FIG. 5 shows an example in which the elastic body 53 is composed of fine metal wires. However, similarly to the radial bearing of FIG. 2, the thrust bearing 5 should also be made of a corrugated elastic body of a thin metal plate. You can also

A pair of thrust bearings 5 thus constructed
Are detachably fixed to the front split housing 14 and the rear housing 15 by fixing means such as screws in the state of the bearing unit 5A. When the rotating shaft 1 rotates, air pressure is generated by the same action as the radial bearing 4, and the rotating shaft 1 is supported in the axial direction in a non-contact manner.

The operation of the spindle device having this structure will be described. When the rotating shaft 1 swings around, the bearing foils 23, 33 and 56 of the radial bearing 4 and the thrust bearing 5 and the elastic bodies 22, 32 and 53 are deformed, and the bearing foils 23 and 3 are deformed.
3, 56 and the elastic body 22, 32, 53, the elastic body 22,
A large damping force is generated by the friction between the bearings 32 and 53 and the bearing housings 21 and 51. Therefore, even when the rotational shaft 1 is largely unbalanced, it can be stably rotated at a high speed. When the elastic bodies 32 and 53 are composed of an assembly of thin metal wires, the thin metal wires also rub against each other, so that a larger damping force is generated than when the elastic body is composed of a thin metal plate.

When both the radial bearing 4 and the thrust bearing 5 are foil bearings as described above, the respective bearing surfaces can be deformed, so that some form errors and assembly errors can be absorbed. Therefore, as compared with the conventional electrostatic coating spindle, the processing accuracy and the assembly accuracy can be significantly eased. Further, it becomes possible to form the bearings 4 and 5 as a unit and individually assemble them into the housing 2 as the bearing units 4A and 5A. The parts do not need to be thick to prevent deformation during processing, and the bearing air supply passages used in hydrostatic gas bearings are not necessary, so the parts that make up the spindle device can be made thinner and lighter. It is possible to reduce the size.

The radial bearing 4 is a bearing unit 4A in which the bearing housing 21, the elastic bodies 22 and 32 and the bearing foils 23 and 33 are integrated, and the thrust bearing 5 is a bearing housing 51, an elastic body 53 and a bearing foil 56 are integrated. Since the respective bearing units 5A are fixed to the housing main body 10 at predetermined positions in a detachable manner,
When the bearings 4 and 5 become unusable due to an accident such as invasion of the liquid to be treated, it is possible to easily replace only the bearing units 4A and 5A and restore the usable state. The rotating shaft 1 can be used by removing and cleaning the adhered liquid after replacing the bearing units 4A and 5A. Therefore, it can be repaired in the field, and unlike conventional spindles, there is no need to return it to the manufacturer, and maintenance costs can be reduced.

In this spindle device, since the unbalanced load acts in the radial direction, the unbalanced damage is
It mainly occurs on the bearing surface of the radial bearing 4. In this embodiment, since the elastic bodies 22 and 32 and the bearing foils 23 and 33 of the radial bearing 4 are fixed to the bearing housing 21 by frictional force, the rotating shaft 1 contacts the bearing foil foils 23 and 33 during rotation. Then, when a torque larger than the frictional force acts, the bearing housing 21
It rotates with the rotating shaft 1 in the inside. Therefore, the rotating shaft 1
It is possible to reduce the damage of.

The bearing surfaces of the bearing foils 23 and 33 facing the rotary shaft 1 or the thrust plate 3 are fixed to the rotary shaft 1 when stationary.
Alternatively, it is in contact with the thrust plate 3 and continues to rotate even after the start of rotation until it reaches a rotation speed at which a sufficient dynamic pressure effect is generated. In order to suppress the wear of the sliding surface at this time, the rotating shaft 1 and the bearing foils 23 and 33 are heat-treated to increase the wear resistance, or the sliding surface has a wear-resistant coating or a lubricating coating ( It is preferable to apply (not shown). As the abrasion resistant coating, nickel plating, chromium plating, titanium nitride coating, amorphous carbon coating, etc. can be adopted. As the lubricous film, plating in which a solid lubricant such as molybdenum disulfide or graphite is dispersed, resin coating, or the like can be adopted.

The above embodiment has been described for the case of being applied to a rotary atomizer spindle device for electrostatic coating, but the present invention can be generally applied to a spindle device in which an atomizing head is attached to a rotary shaft. .

[0038]

The spindle device of the present invention includes a rotary shaft having a head mounting portion to which an atomizing head is mounted, and a radial bearing and a thrust bearing for rotatably supporting the rotary shaft with respect to a housing. In the above, the radial bearing and the thrust bearing are respectively a bearing foil having a bearing surface facing the rotating shaft,
Since the foil bearing has the elastic body for elastically supporting the bearing foil between the housing and the bearing foil, the allowable unbalance amount is large, the atomizing head is deformed, and the treated liquid or its solidified material is deviated. Even if it sticks, it can rotate normally. Further, since the accuracy of the parts can be relaxed, not only the manufacturing cost can be reduced, but also the parts can be thinned to reduce the weight and size of the spindle device. If the radial bearings are individually unitized and detachably attached to the housing,
It is easy to repair when the bearing is damaged. When the elastic body of the radial bearing and the bearing foil are fixed to the housing by elastic restoring force, when the rotating shaft and the bearing foil come into contact with each other during high-speed rotation and excessive torque is generated, The elastic body can rotate with the rotating shaft, and damage to the rotating shaft can be mitigated.

[Brief description of drawings]

FIG. 1 is a sectional view of a spindle device according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view of a radial bearing in the spindle device.

FIG. 3 is a cross-sectional view of a modified example of the radial bearing.

FIG. 4 is a vertical cross-sectional view showing a modified example of the mounting structure of the radial bearing.

FIG. 5 is an exploded perspective view of a thrust bearing in the spindle device.

FIG. 6 is a sectional view of a conventional example.

FIG. 7 is a cross-sectional view of another conventional example.

8 is a sectional view taken along line VIII-VIII of FIG.

9A to 9C are cross-sectional views showing various examples of conventional foil bearings.

[Explanation of symbols]

1 ... Rotation axis 1a ... Atomizing head mounting part 2 ... Housing 3 ... Thrust plate 4 ... Radial bearing 4A ... Bearing unit 5 ... Thrust bearing 5A ... Bearing unit 10 ... Main body housing 10A ... External case 11 ... Atomizing head 12 ... Injection nozzle 14, 15 ... Split housing 18 ... Turbine blade 19 ... Drive mechanism 21 ... Housing 22 ... Elastic body 23 ... Bearing foil 32 ... Elastic body 33 ... Bearing foil 51 ... Bearing housing 53 ... Elastic body 56 ... Bearing foil

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Claims (8)

[Claims] 1. A spindle device comprising a rotary shaft having a head mounting portion to which an atomizing head is mounted, and a radial bearing and a thrust bearing for rotatably supporting the rotary shaft with respect to a housing, wherein the radial bearing and the thrust are provided. A spindle device characterized in that the bearing is a foil bearing having a bearing foil each having a bearing surface facing the rotating shaft, and an elastic body between the housing and the bearing foil for elastically supporting the bearing foil. . 2. The spindle according to claim 1, wherein a plurality of the radial bearings are provided, the rotary shaft has a thrust plate, and the thrust bearings include a pair of thrust bearings facing each other on both sides of the thrust plate. apparatus. 3. The foil bearing according to claim 1, wherein at least one of the radial bearing and the foil bearing serving as a thrust bearing has an elastic body constituting the foil bearing made of an assembly of fine metal wires. Spindle device. 4. A bearing foil and an elastic body of the radial bearing are coupled to each other, and the elastic body is elastically deformed and incorporated into an inner diameter surface of the housing, and the elastic body and the bearing foil are elastically restored by the elastic body. The spindle device according to any one of claims 1 to 3, which is fixed to an inner diameter surface of the housing by means of. 5. A plurality of the radial bearings are provided, and the housing is divided into a bearing housing for supporting elastic bodies and bearing foils of each radial bearing, and a main body housing to which the bearing housing is detachably mounted. The spindle device according to any one of claims 1 to 4. 6. The main body housing, an outer case,
The spindle device according to claim 5, wherein the outer housing is detachably mounted and a plurality of radial bearing bearing housings are split into split housings. 7. A spindle device comprising: a rotary shaft having a head mounting portion to which an atomizing head is mounted; and a radial bearing rotatably supporting the rotary shaft with respect to a housing. A foil bearing comprising a bearing foil having a bearing surface facing the shaft, and an elastic body between the housing and the bearing foil for elastically supporting the bearing foil, wherein the elastic body comprises an assembly of fine metal wires. A spindle device characterized by the above. 8. A spindle device for a rotary atomizer, wherein the atomizing head atomizes liquid by centrifugal force, the rotary shaft is a hollow shaft, and the atomizing is performed in the rotary shaft. A nozzle for supplying a liquid for atomization to the head is inserted, a turbine blade is provided on the outer periphery of the rotating shaft, and a turbine nozzle for blowing a compressed gas to the turbine blade is provided in the housing. 6. The spindle device according to any one of 6.