JP2000192959A - Air spindle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a large air spindle by providing an air spindle having the constitution capable of relieving dimensional accuracy of respective parts. SOLUTION: In this air spindle, for example, a main spindle 10 and a thrust plate 30 are joined at an almost right angle in an angle freely displaceable state, and since an installing angle of the main spindle and the thrust plate is automatically corrected, accuracy of the installing angle of the main spindle and the thrust plate can be relieved. In the air spindle having an axial bearing 50 arranged in a housing 60 in an angle freely displaceable state in the shaft direction of an axial bearing surface, since a shaft directional angle of the axial bearing surface is automatically corrected, plane accuracy of a thrust member and installing accuracy of a rotary shaft member of the thrust member can be relieved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air spindle device, and corresponds to an increase in the size of an air spindle device.

[0002]

2. Description of the Related Art FIG. 7 shows a general structure of a conventional air spindle.

The air spindle comprises a main shaft 1 and a main shaft 1
A thrust plate 2 mounted at right angles to both ends of the thrust plate, a bearing sleeve 3 facing the outer peripheral surface of the main shaft 1, an axial bearing member 4 facing the inner surface of the thrust plate 2, and a bearing sleeve 3
And a housing 5 for fixing the axial bearing member 4 to the housing.

[0004] The bearing sleeve 3 has a radial bearing surface 3a facing the outer peripheral surface of the main shaft with a small gap on the inner diameter surface, and has a plurality of air supply nozzles 3b opened to the radial bearing surface 3a. The axial bearing member 4 includes the thrust plate 2
An axial bearing surface 4a is formed to face with a minute gap, and has a plurality of air supply nozzles 4b opened to the axial bearing surface 4a. The housing 5 has inside each of the air supply nozzles (3 b, 3 b) of the bearing sleeve 3 and the axial bearing member 4.
An air supply passage 5a communicating with the air supply passage 4a is formed, and an air supply connector 5b is attached to an opening outside the air supply passage 5a.

The air spindle is provided with an air supply connector 5b.
Compressed air that has entered through the air supply passage 5a and blows out from the air supply nozzles (3b, 4b) to form an air bearing.

[0006]

Since the clearance between the bearings of the air spindle is several μm, the precision dimensions of each member (for example, the flatness of the bearing surface, the perpendicularity between the main shaft and the thrust plate) are also several μm.
m or less. By the way, in recent years, there has been a demand for a large air spindle, but when manufacturing a large air spindle, processing the single-piece precision dimensions of each member with high accuracy requires problems such as equipment, cost, and long term. There is a limit to the realization due to the need for processing.

An object of the present invention is to provide an air spindle having a configuration capable of relaxing the dimensional accuracy of each part, and to realize a large-sized air spindle.

[0008]

An air spindle according to the present invention comprises a rotating shaft member, a thrust member mounted at a substantially right angle to the rotating shaft member so that the angle is freely displaceable, and an outer peripheral surface of the rotating shaft member. A radial bearing surface having a small radial bearing gap, a radial bearing member having an air supply nozzle formed in the radial bearing surface, and an axial bearing surface facing the end surface of the thrust member with a small axial bearing gap; An axial bearing member having an air supply nozzle opened to the axial bearing surface, and a rotary shaft member formed by an air film of compressed air supplied to each bearing gap from each air supply nozzle of the radial bearing member and the axial bearing member. And the thrust member are supported in a non-contact manner with respect to each bearing surface.

Also, a rotating shaft member, a thrust member mounted substantially at right angles to the rotating shaft member, a housing for accommodating the rotating shaft member, and a radial bearing facing the outer peripheral surface of the rotating shaft member with a small radial bearing gap. A radial bearing member disposed in the housing, an axial bearing surface facing the end surface of the thrust member with a small axial bearing gap, and an axial bearing. An axial bearing member disposed in the housing in a state where the angle of the axial bearing surface with respect to the axial direction is freely displaceable, and the supply of the radial bearing member and the axial bearing member is provided. The rotating shaft member and thrust member are not in contact with each bearing surface by the air film of compressed air supplied to each bearing gap from the air nozzle It is intended to equity.

[0010] Further, the rotary shaft member and the thrust member are mounted at a substantially right angle in a state where the angle is freely displaceable, and the axial bearing surface and the axial bearing surface facing each other with a small axial bearing gap from the end surface of the thrust member. And an axial bearing member provided in the axial bearing region of the housing in a state where the angle of the axial bearing surface with respect to the axial direction is displaceable.

For example, the mounting structure of the rotating shaft member and the thrust member may be such that the rotating shaft member and the thrust member are mounted via a bellows member.

The axial bearing member comprises a first member on the side forming the axial bearing surface and a second member attached to the housing, and the first member and the second member are joined by spherical sliding contact. It may be good.

Further, magnets are provided for attracting each other to a bearing-side end of the rotary shaft member and a bearing bottom of the rotary shaft member facing the bearing-side end, and the magnet is used to move the rotary shaft member toward the axial bearing. A necessary axial clearance may be secured by generating an axial reactive force to be pulled and balancing the axial reactive force with the axial bearing force generated in the axial bearing clearance.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An air spindle according to one embodiment of the present invention will be described below with reference to the drawings.

As shown in FIG. 1, the air spindle according to this embodiment includes a main shaft 10, a bellows member 20, a thrust plate 30, a radial bearing 40, and an axial bearing 50.
And the housing 60 as main components. For convenience of description, the up and down direction is defined with the side on which the thrust plate 30 is set with respect to the housing 60 in FIG.

The main shaft 10 is a cylindrical member having an upper end formed with a fitting portion 12 into which a bellows member 20 is fitted, and a lower end to which a metal plate 14 made of a magnetic metal material is fastened by bolts. .

As shown in FIG. 2, the bellows member 20 is a metal tube having a plurality of circumferential grooves 22 provided on an outer diameter surface thereof. Having. A fitting portion 24 corresponding to the fitted portion 12 of the main shaft 10 is formed at a lower end of the bellows member 20. Further, a bolt hole 26 for fixing the thrust plate 30 is formed at the upper end of the bellows member 20.

The thrust plate 30 is a disc-shaped member, and the bellows member 2
A bolt hole 32 is formed at a position corresponding to the zero bolt hole 26.

The radial bearing 40 has a double inner and outer sleeve structure composed of a bearing sleeve 42 and a piping sleeve 44. The bearing sleeve 42 is fitted and fixed to the inner diameter surface of the piping sleeve 44. The inner diameter surface of the bearing sleeve 42 is
A radial bearing surface 42a is formed to face the outer diameter surface 10a of the main shaft 10 via a small radial gap. The outer diameter surface of the bearing sleeve 42 is provided with a plurality of air supply nozzles 42b that open to the radial bearing surface 42a. Piping sleeve 4
4 has an air supply passage 44a formed therein so as to communicate with each air supply nozzle 42b of the bearing sleeve 42 when the bearing sleeve 42 is fitted and fixed. Air supply passage 44
“a” is open at the lower end of the piping sleeve 44, and an air supply connector 44b is attached to this opening.

As shown in FIG. 3, the axial bearing 50
Has an axial bearing plate 52, a spacer 54, a mounting shaft 56, and a spherical bearing 58, as shown in FIG.
On the lower surface of the thrust plate 30, six axial bearings 50 are evenly arranged.

The axial bearing plate 52 is a disk-shaped member and has an axial bearing surface 52a formed on the upper surface. Inside the axial bearing plate 52, a plurality of air supply nozzles 52b opening to the axial bearing surface 52a, and each air supply nozzle 52b
And an air supply passage 52c opened at the center of the lower surface. The spacer 54 is a disc-shaped member, and has an air supply hole 54a formed at the center thereof. The spacer 54 is attached to the lower surface of the axial bearing plate 52 so that the centers thereof are aligned. The mounting shaft portion 56 is a substantially cylindrical box-shaped body, the lower surface is open, the upper surface is formed with an air supply hole at the center, and is mounted on the lower surface of the spacer 54 so that the centers match. An air supply connector 56a is mounted in the air supply hole of the mounting shaft portion 56 inside the box. The air supply connector 56a of the mounting shaft 56 communicates with the air supply hole of the mounting shaft 56, the air supply hole 54a of the spacer 54, and the air supply passage 52c of the thrust bearing plate 52. The spherical bearing 58 includes an inner diameter member 58a and an outer diameter member 58b that make spherical sliding contact with each other. The inner diameter member 58a has an inner diameter corresponding to the outer diameter of the mounting shaft portion 56, and has a mounting hole 58c in which the mounting shaft portion 56 is fitted and fixed.

The housing 60 is a circular member and has a radial bearing mounting portion 62 and an axial bearing mounting portion 64. The radial bearing mounting part 62 is formed in the center of the housing 60 so as to be hollow in a substantially circular shape in the axial direction. The radial bearing mounting portion 62 has a shoulder portion 62a formed at an upper end portion,
A lower support plate 66 is attached to the lower end. Lower support plate 66
Is a disk-shaped member, in which a magnet 66a is disposed in the center,
An insertion hole 66b for inserting an air supply hose (not shown) is formed at a position corresponding to the air supply connector 44b provided on the piping sleeve 44 of the radial bearing 40.
The axial bearing mounting portions 64 are formed at six locations in the circumferential direction around the center of the housing 60 so as to be hollowed out in a substantially circular shape in the axial direction. A shoulder 64 a corresponding to the outer diameter member 58 b of the spherical bearing 58 of the axial bearing 50 is formed at the upper end of the axial bearing mounting portion 64.

This air spindle is assembled as follows.

The radial bearing 40 is mounted on a shoulder 62a of a radial bearing mounting portion 62 of the housing 60 and is mounted by bolting. In the axial bearing 50, the outer diameter member 58b of the spherical bearing 58 is fitted to the shoulder 64a of the axial bearing mounting portion 64 of the housing 60, and is fixed by retaining. The main shaft 10 is disposed on a radial bearing surface 42a of the radial bearing 40 with a predetermined radial bearing gap. The bellows member 20 is fitted and fixed to the upper end of the main shaft 10. The thrust plate 30 is bolted with the bellows member 20 centered. At this time, in order to make the axial bearing gap uniform on the lower surface of the thrust plate 30, six axial bearings 50 set in the circumferential direction are provided.
The thickness of the spacer 54 of each axial bearing 50 is adjusted so that the upper surfaces of the axial bearings 50 can form the same plane.

An air supply hose (not shown) is inserted into the radial bearing 40 through an insertion hole 66b formed on the lower surface of the housing 60, and compressed air is sent to the air supply connector 44b. The compressed air is supplied from the air supply connector 44b to the air supply passage 44.
a through the air supply nozzle 42b opening in the radial bearing surface 42a to form an air film in the radial bearing gap, thereby supporting the main shaft 10 in a non-contact manner.

An air supply hose (not shown) is inserted into the axial bearing 50 from the lower surface of the axial bearing mounting portion 64 of the housing 60, and compressed air is sent to the air supply connector 56b. The compressed air passes through the air supply hole 54a and the air supply passage 52c from the air supply connector 56b, and blows out from the air supply nozzle 52b opened on the axial bearing surface 52a.
An air film is formed in the axial bearing gap, and the thrust plate 30 is formed.
In a non-contact manner.

This air spindle has a radial bearing 40
A radial bearing gap is formed between the radial bearing surface 42 a of the main shaft 10 and the outer diameter surface 10 a of the main shaft 10.
An axial bearing gap is formed between the zero axial bearing surface 52a and the lower surface 30a of the thrust plate 30. Therefore, it is necessary to strictly control the dimensional accuracy of the radial bearing surface 42a of the radial bearing 40, the outer diameter surface 10a of the main shaft 10, the axial bearing surface 52a of the axial bearing 50, and the lower surface 30a of the thrust plate 30.

However, this air spindle is in a state in which the mounting angle between the main shaft 10 and the thrust plate 30 is freely displaceable by the bending of the bellows member 20 arbitrarily, so that the air film in the radial bearing gap and the axial bearing gap is more powerful. Receiving
Since the angle between the main shaft 10 and the thrust plate 30 is automatically corrected to maintain a required radial bearing clearance, the main shaft 1
The accuracy of the mounting angle between 0 and the thrust plate 30 can be relaxed.

Since each axial bearing 50 is mounted on the housing 60 via the spherical bearing 58,
The axial angle of the axial bearing surface 52a is freely displaceable. The axial bearing angle of the axial bearing surface 52a is automatically corrected by receiving a force from the air film in the radial bearing gap and the axial bearing gap. Since a required axial bearing clearance is secured between the thrust plate 3 and the lower surface.
The flatness of zero and the accuracy of the mounting angle between the thrust plate 30 and the spindle 10 can be reduced.

In this type of air spindle, the required axial bearing gap can be set by balancing the own weight of the main shaft 10 and the thrust plate 30 in the axial direction with the axial bearing force generated in the axial bearing gap. . However, if the balance between the weight of the main shaft 10 and the thrust plate and the axial bearing force is poor, it is necessary to correct this. In addition, the operation of the air spindle is more stable when the balance in the axial direction is secured. Therefore, the air spindle of this embodiment includes a metal plate 14 of the main shaft 10 and
The metal plate 14 of the main shaft 10 and the magnet 66a of the lower support plate 66 of the housing 60 facing each other generate an axial reaction force that attracts each other and pulls the main shaft downward in the axial direction.
By balancing the axial reaction force and the axial bearing force generated in the axial bearing gap, a more stable bearing gap is secured.

As described above, this air spindle can tolerate a slight dimensional error that may occur in the plane accuracy of the thrust plate and the mounting angle between the main shaft and the thrust plate, so that a low-cost large air bearing can be realized. it can.

The embodiment of the air spindle according to the present invention has been described above. However, the air spindle according to the present invention is not limited to the embodiment and can be variously modified.

For example, the air spindle may be configured so that only the mounting angle between the main shaft and the thrust plate can be displaced, and a required bearing clearance is ensured. Further, the axial bearing of the axial bearing may be configured to be displaceable only in the axial direction, and a required bearing clearance may be secured.

The axial bearing may have the structure shown in FIG.

The axial bearing 70 has an axial bearing plate 72, a mounting shaft member 74, and a spacer 76. The axial bearing plate 72 is a disc-shaped member, and has an axial bearing surface 72a formed on the upper surface. The axial bearing plate 72 communicates with the plurality of air supply nozzles 72b opening inside the axial bearing surface 72a and the air supply nozzles 72b. An air supply passage 72c is provided at the center of the lower surface of the bearing plate 72. The lower surface of the axial bearing plate 72 has a spherical recess 72d at the center.
Are formed.

The mounting shaft member 74 is a substantially circular box-like body having an open lower surface, an upper surface having a spherical shape 74a corresponding to the spherical surface of the lower surface of the axial bearing plate 72, and an air supply hole 74b at the center thereof. The air supply connector 74c is attached to the lower end opening of the air supply hole 74b. In addition, a flange 74d protruding in the radial direction is provided on the upper part on the peripheral side of the mounting shaft member 74, and a bolt hole is formed in the flange 74d.

The spacer 76 is a ring-shaped plate member that can be inserted into the outer peripheral surface of the mounting shaft member 74, and includes an axial bearing plate 72.
Is to adjust the mounting height.

The axial bearing 70 is provided in the housing 6
The mounting shaft member 74 is fastened to the axial bearing mounting portion 64 ′ of 0 ′ via a spacer 76 with a bolt (not shown),
An axial bearing plate 72 is provided on the spherical upper surface of the mounting shaft member 74.
Is placed. At this time, the thickness of each spacer 76 is adjusted so that the upper surface of each axial bearing plate 72 can form the same plane. The axial bearing 70 has an axial bearing surface 7 by making a spherical sliding contact between the lower surface of the axial bearing plate 72 and the upper surface of the mounting shaft member 74.
The axial angle of 2a is freely displaceable. Like the above-described axial bearing, the axial angle of the axial bearing surface 52a is automatically corrected by receiving the force from the radial bearing gap and the air film in the axial bearing gap. Therefore, the accuracy of the plane of the thrust plate and the accuracy of the mounting angle between the main shaft and the thrust plate can be reduced.

The joint between the main shaft and the thrust plate may have a joint structure shown in FIG. 6 instead of the bellows member.

In this joint structure, pocket holes 82 are provided at a plurality of positions in the circumferential direction at the upper end of the main shaft 10 ', and one bolt hole 84 is provided. Then, an elastic body 86 and a steel ball 88 are put into the pocket hole 82. At this time, the steel ball 88 slightly protrudes from the upper end of the main shaft 10 '. Main shaft 10 'and thrust plate 3
0 'with bolts. At this time, due to the elastic deformation of the elastic body 86, the mounting angle between the main shaft 10 'and the thrust plate 30' is in a displaceable state, and receives a force from the air film in the radial bearing gap and the axial bearing gap, and the main shaft 10 ' Since the mounting angle with the thrust plate 30 'is automatically corrected, similarly to the above-mentioned bellows member, the main shaft 10' and the thrust plate 3 '
The accuracy of the mounting angle with 0 'can be relaxed.

If the air spindle of the present embodiment is used, a large air spindle can be constructed. For example, as shown in FIG. 1, a rotor 16 is provided on the outer surface of the main shaft 10, and By providing the stator coil 46 on the bearing sleeve 42 of the radial bearing 40, a large-sized motor device can be realized.

[0042]

The air spindle according to the present invention, which is mounted at a substantially right angle so that the angle between the rotating shaft member and the thrust member is freely displaceable, is such that the perpendicularity between the rotating shaft member and the thrust member is automatically adjusted. And the required bearing clearance is maintained, so that the accuracy of the mounting portion between the rotary shaft member and the thrust member can be reduced.

In the case where the axial bearing member is provided in the axial bearing region of the housing such that the angle of the axial bearing surface with respect to the axial direction is freely displaceable, the axial angle of the axial bearing surface is automatically corrected. As a result, the required bearing clearance is ensured, so that the planar accuracy of the thrust member and the accuracy of the mounting angle between the thrust member and the rotary shaft member can be reduced.

Further, in the case where magnets are attracted to each other at a bearing end of the rotating shaft member and a bearing bottom portion at which the bearing end of the rotating shaft member is opposed, the rotating shaft member is axially supported by the magnet. Since an axial reaction force pulling to the side can be generated, a more stable bearing gap can be secured by balancing the axial reaction force with the axial bearing force generated in the axial bearing gap.

[Brief description of the drawings]

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

FIG. 2 is a longitudinal sectional view of the vicinity of a bellows member of the air spindle according to the embodiment of the present invention.

FIG. 3 is a longitudinal sectional view of an axial bearing of the air spindle according to the embodiment of the present invention.

FIG. 4 is a plan view of an air spindle according to one embodiment of the present invention.

FIG. 5 is a longitudinal sectional view of an axial bearing of an air spindle according to another embodiment of the present invention.

FIG. 6 is a longitudinal sectional view showing a joint structure between a main shaft of an air spindle and a thrust plate according to another embodiment of the present invention.

FIG. 7 is a longitudinal sectional view of a conventional air spindle.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Main shaft 14 Metal plate 20 Bellows member 30 Thrust member 40 Radial bearing 50 Axial bearing 58 Spherical bearing 60 Housing 66a Magnet

Claims (6)

[Claims] 1. A rotary shaft member, a thrust member mounted to the rotary shaft member at a substantially right angle so that the angle is displaceable, and a radial bearing opposed to an outer peripheral surface of the rotary shaft member with a small radial bearing gap. Surface, a radial bearing member having an air supply nozzle formed in the radial bearing surface, an axial bearing surface facing the end surface of the thrust member with a small axial bearing gap, and an opening in the axial bearing surface. An axial bearing member having an air supply nozzle; and an air film of compressed air supplied to each bearing gap from each air supply nozzle of the radial bearing member and the axial bearing member. An air spindle characterized by being supported in a non-contact manner with respect to each bearing surface. 2. A rotary shaft member, a thrust member mounted substantially at a right angle to the rotary shaft member, a housing for accommodating the rotary shaft member, and a small radial bearing gap with an outer peripheral surface of the rotary shaft member. A radial bearing member having a radial bearing surface, and an air supply nozzle formed in the radial bearing surface, and a radial bearing member disposed in the housing, and an axial surface facing the end surface of the thrust member with a small axial bearing gap. An axial bearing member having a bearing surface and an air supply nozzle opened to the axial bearing surface, wherein the axial bearing member is disposed in the housing such that an angle of the axial bearing surface with respect to an axial direction is freely displaceable; The rotary shaft member is formed by an air film of compressed air supplied to each bearing gap from each air supply nozzle of the radial bearing member and the axial bearing member. An air spindle for supporting a bearing and a thrust member in a non-contact manner with respect to each bearing surface. 3. The air spindle according to claim 2, wherein the rotating shaft member and the thrust member are mounted at a substantially right angle so that the angle is freely displaceable. 4. The air spindle according to claim 1, wherein the rotating shaft member and the thrust member are mounted via a bellows member. 5. The axial bearing member comprises a first member on an axial bearing surface side and a second member attached to a housing, and the first member and the second member are joined by spherical sliding contact. 3. The method according to claim 2, wherein
The described air spindle. 6. A magnet which attracts each other to a bearing-side end of the rotary shaft member and a bearing bottom of the rotary shaft member facing the bearing-side end. The air spindle according to any one of claims 1 to 3, wherein an axial reaction force is generated, and a required bearing clearance is ensured by balancing the axial reaction force and the axial bearing force generated in the axial bearing clearance.