JP5308280B2 - Static pressure gas bearing - Google Patents

Description

  The present invention relates to a static pressure gas bearing that is between a fixed portion and a rotating portion and supports the rotating portion, and particularly relates to a static pressure gas bearing that has an automatic alignment function and is an assembly part (also referred to as assembly).

  Conventionally, hydrostatic gas bearings have high rotational accuracy and no frictional resistance, and are therefore mainly used for high-precision rotary tables for precision inspection devices and high-speed rotary shafts for high-speed processing machines.

  As a static pressure gas bearing, the sleeve is elastically supported on the inner peripheral surface of the housing via at least two O-rings, so that the O-ring absorbs the swirling of the sleeve and the contact between the bearing surface and the shaft is maintained. The thing which prevented is proposed (for example, refer patent document 1).

  As another hydrostatic gas bearing, an O-ring is interposed between the hydrostatic bearing portion and the cover portion, so that a non-uniform gap (gap) due to distortion (distortion) of the housing is caused in the O-ring. There has been proposed a structure that can be easily assembled without absorbing the processing accuracy of the housing and without using an assembly adjustment jig (see, for example, Patent Document 2).

JP-A-8-219159 (paragraphs 0007, 0009, 0022, FIG. 1) JP 7-35140 A (paragraphs 0010, 0011, 0026, FIG. 1)

  However, in order to exhibit the performance of the static pressure gas bearing, the apparatus itself to which the static pressure gas bearing is assembled is required to have high accuracy, for example, the right angle of the housing with respect to the shaft and the straightness of the shaft. The apparatus which can assemble a gas bearing will be limited.

  In the hydrostatic gas bearing according to Patent Document 1, since the thrust bearing is configured to sandwich the flat thrust bearing of the flange-shaped flange portion protruding from one end side portion of the shaft, the sleeve It cannot absorb the thrust swing in the thrust direction.

  In the static pressure gas bearing according to Patent Document 2, the radial bearing gap (referred to as the gap between the bearing hole of the static pressure bearing portion and the rotating shaft in Patent Document 2) must be adjusted to several μm. Assembly of gas bearings requires advanced assembly technology and accurate measurement technology.

  Accordingly, an object of the present invention is to solve the above-described problems and to provide a static pressure gas bearing as an assembly part having an automatic alignment function.

In order to solve the above-mentioned problems, in the inventions according to claim 1 and claim 2 , the hydrostatic gas bearing is opposed to the outer peripheral surface of the shaft and is opposed to the inner peripheral surface of the housing. A radial bearing gap formed between the bearing surfaces, and a radial bearing surface and a thrust bearing surface provided on surfaces of the inner cylinder housing or the outer cylinder housing facing each other. Compressed gas was supplied to the thrust bearing gap to keep the shaft and housing in a non-contact state. And the 1st elastic body was provided in the surface on the back side with respect to the radial bearing clearance. Furthermore, the second elastic body is provided on the casing on the back side with respect to the thrust bearing gap and provided with the first elastic body.

According to the invention which concerns on Claim 1 and Claim 2 , from the inner cylinder housing | casing arrange | positioned a static pressure gas bearing facing the outer peripheral surface of an axis | shaft, and the outer cylinder housing | casing arrange | positioned facing the inner peripheral surface of a housing A radial bearing surface and a thrust bearing surface are provided on the mutually facing surfaces of the inner cylinder housing or the outer cylinder housing, and compressed gas is supplied to the radial bearing gap and the thrust bearing gap formed between the bearing surfaces. Since the shaft and the housing are held in a non-contact state, the static pressure gas bearing can be assembled into a component.

In other words, according to the first and second aspects of the invention, since the bearing surface is provided inside the static pressure gas bearing, for example, if it is assembled in advance with the radial bearing gap adjusted, At the assembly site of the hydrostatic gas bearing, the assembled hydrostatic gas bearing is inserted into the fitting part of the housing without adjusting the clearance between the radial bearing surface and the support shaft to several μm. This makes it possible to easily attach a static pressure gas bearing. For this reason, it is possible to prevent the static pressure gas bearing from being damaged during the assembling work or the adjustment work of the static pressure gas bearing.

According to the first and second aspects of the invention, since the first elastic body is provided on the back surface with respect to the radial bearing gap, the perpendicularity accuracy of the housing with respect to the shaft is inferior. However, the first elastic body is weak in the wide gap and is strongly compressed in the narrow gap, and can deform according to the gap to absorb the deviation in the squareness accuracy of the housing. Therefore, the static pressure gas bearing can be easily attached only by inserting the assembled static pressure gas bearing into the fitting portion of the housing.

  When the straightness accuracy of the shaft is inferior, the so-called jump rope phenomenon in the radial direction during operation of the apparatus (for example, when the shaft makes one revolution, the shaft is deviated from the axial center by a straightness deviation every half rotation. This occurs when the rotation angle of the shaft and the housing changes, and the radial bearing gap cannot be maintained because the angle between the shaft and the housing changes. The first elastic body is deformed and the radial bearing is tilted with respect to the shaft. (This movement is called that the bearing swings its head). That is, by deforming the first elastic body, the angle between the radial bearing and the shaft can be continuously changed following the change in the angle between the shaft and the housing. Since the radial bearing is provided with the swing mechanism in this manner, the radial bearing gap can be automatically adjusted to the parallel and optimum interval even if the angle between the shaft and the housing changes.

According to the first and second aspects of the invention, the second elastic body is provided on the casing on the back side of the thrust bearing gap and provided with the first elastic body. Therefore, even when the perpendicularity accuracy of the housing with respect to the shaft is inferior, the inner cylindrical housing or the outer cylindrical housing is biased in the thrust direction by the second elastic body, so that the thrust bearing gap is automatically parallelized. And it can adjust to an optimal space | interval. Therefore, the static pressure gas bearing can be easily attached only by inserting the assembled static pressure gas bearing into the fitting portion of the housing.

  In addition, for example, when the shaft moves in the thrust direction by applying a load, the second elastic body expands and contracts, and moves the inner cylinder housing or the outer cylinder housing following the movement of the shaft. Can do. Thus, since the shock-absorbing mechanism is provided in the thrust bearing, the thrust bearing gap can be automatically adjusted to a parallel and optimum interval.

As described above, according to the first and second aspects of the present invention, the radial bearing gap and the thrust bearing gap are automatically adjusted to the parallel and optimum intervals by the self-aligning function of the swing mechanism and the buffer mechanism. can do. As a result, a static pressure gas bearing can be attached even to a device that is inferior in accuracy of the perpendicularity of the housing relative to the shaft or the straightness of the shaft.

Further, according to the inventions according to claim 1 and claim 2 , since the bearing clearance is automatically maintained in parallel and at an optimum interval, a non-contact state can be maintained and frictional resistance can be eliminated. Can be demonstrated. And it can also contribute to the improvement of inspection accuracy and processing accuracy of a device to which low power consumption, rotation error is reduced, and by extension, a static pressure gas bearing is attached.

  In addition to these, as a unique effect of the static pressure gas bearing, maintenance is easy because there is no need for lubrication unlike a rolling bearing, and there is no wear due to friction as in a rolling bearing, and the service life is also long.

It is a perspective view of the static pressure gas bearing which concerns on embodiment. It is a disassembled perspective view of the static pressure gas bearing which concerns on embodiment. It is sectional drawing which shows the mode of the tracking to the angle change of the spin coater which attached the static pressure gas bearing which concerns on embodiment. It is sectional drawing which shows the mode of the tracking to the thrust direction of the spin coater which attached the static pressure gas bearing which concerns on embodiment. It is a perspective view of the static pressure gas bearing which concerns on other embodiment. It is a disassembled perspective view of the static pressure gas bearing which concerns on other embodiment. It is a whole perspective view of the guide roll apparatus which attached the static pressure gas bearing which concerns on other embodiment. It is principal part sectional drawing of the guide roll apparatus which attached the static pressure gas bearing which concerns on other embodiment. It is sectional drawing which shows the mode of the self-alignment of the guide roll apparatus which attached the static pressure gas bearing which concerns on other embodiment.

  Next, embodiments of the present invention will be described in detail with reference to the drawings as appropriate. FIG. 1 is a perspective view of a hydrostatic gas bearing according to the embodiment, and FIG. 2 is an exploded perspective view of the hydrostatic gas bearing according to the embodiment.

  As shown in FIG. 1, the static pressure gas bearing 1 includes an inner cylindrical housing 2 that is disposed to face the outer peripheral surface of the shaft, and an outer cylindrical housing 3 that is disposed to face the inner peripheral surface of the housing. It is configured. And the outer cylinder housing | casing 3 is equipped with the 1st elastic body 4 cyclically | annularly in the outer peripheral surface, and the 2nd elastic body 5 in the end surface.

  As shown in FIG. 2, the inner cylinder housing 2 includes an inner cylinder 21 that is a cylindrical member, and a flange 22 that is a flange-shaped member disposed on one end surface thereof. .

  The outer cylinder housing 3 is a cylindrical member, and a radial bearing surface 3a made of a porous material is formed on an inner peripheral surface thereof, and a thrust bearing surface 3b made of a porous material is formed on one end surface thereof.

  The inner cylinder housing 2 and the outer cylinder housing 3 have the flange surface 22 and the thrust bearing surface 3b so that the outer peripheral surface of the inner tube 21 and the radial bearing surface 3a face each other with a radial bearing gap. A thrust bearing gap is provided so as to face each other.

  The outer cylinder housing 3 has a first elastic body 4, in this case an O-ring 4, in the center of the outer cylinder housing 3 on the outer peripheral surface (corresponding to the surface on the back side of the radial bearing gap). One is provided. Further, the outer cylindrical housing 3 has a second elastic body 5, in this case, a spring 5, on the end surface where the thrust bearing surface 3 b is not formed (corresponding to the surface on the back side with respect to the thrust bearing gap). There are several on the top.

  The static pressure gas bearing 1 configured as described above is assembled in the state where the inner cylinder housing 2 and the outer cylinder housing 3 adjust the radial bearing gap, and are assembled into assembly parts. The static pressure gas bearing 1 is attached to the apparatus by inserting the pre-assembled static pressure gas bearing 1 into the fitting portion of the housing at the assembly site of the static pressure gas bearing 1.

  FIG. 3 is a cross-sectional view showing how the spin coater attached with the hydrostatic gas bearing 1 according to the embodiment follows the change in angle, and FIG. 4 shows a spin attached with the hydrostatic gas bearing 1 according to the embodiment. It is sectional drawing which shows the mode of the tracking to the thrust direction of a coater.

  As shown in FIGS. 3 and 4, the hydrostatic gas bearing 1 has an inner cylindrical housing 2 that faces the outer peripheral surface of the rotation axis of the spin coater Sc, and an outer cylindrical housing 3 that faces the inner peripheral surface of the housing H. In this state, it is attached to the spin coater Sc.

  In the static pressure gas bearing 1, a first elastic body 4, here an O-ring 4, is provided on the outer peripheral surface of the outer cylinder housing 3 (corresponding to the surface on the back side with respect to the radial bearing gap). And the housing H.

  Further, the hydrostatic gas bearing 1 has a second elastic body 5 on the end surface (corresponding to the back surface of the thrust bearing gap) where the thrust bearing surface 3b of the outer casing 3 is not formed. Then, the springs 5 a and 5 b are inserted into a concave portion formed in the outer cylinder housing 3 in a state where the springs 5 a and 5 b are pressed and contracted by the outer cylinder housing 3 and the housing H.

  In the static pressure gas bearing 1 configured as described above, as shown in FIG. 3, the O-ring 4 and the springs 5a and 5b are deformed even if the housing H is inferior in squareness accuracy with respect to the shaft. The hydrostatic gas bearing 1 made into a component is attached by simply inserting it into the fitting portion of the housing H, and the hydrostatic gas bearing 1 is automatically aligned so as to be perpendicular to the rotation axis.

  More specifically, in the housing H that is inferior in squareness accuracy with respect to the shaft, the gap amount between the shaft and the housing H is non-uniform. However, in the static pressure gas bearing 1, the O-ring 4 is weak in a wide gap and is strongly compressed and deformed in a narrow gap to absorb a non-uniform gap amount. At this time, as shown in FIG. 3, when the gap amount between the end surface where the thrust bearing surface 3 b is not formed (corresponding to the surface on the back side with respect to the thrust bearing gap) and the housing H is not uniform, the spring 5 a While the spring 5b is extended, the outer cylinder housing 3 is continuously urged toward the thrust bearing surface 3b while the spring 5b is contracted. As a result, the static pressure gas bearing 1 is automatically aligned so as to be perpendicular to the rotation axis, and the radial bearing gap and the thrust bearing gap are also maintained in parallel and at an optimum interval.

  In addition, when the straightness accuracy of the shaft is inferior, when the shaft is rotated, the angle between the shaft and the housing H changes, contact of the bearing portion occurs, and the bearing performance cannot be exhibited. However, in the static pressure gas bearing 1, the O-ring 4 is squeezed while sliding in the direction in which force is applied, and the springs 5 a and 5 b expand and contract so as not to hinder the movement of the outer casing 3. Follows the change in the angle between the shaft and the housing H, and continuously moves so as to swing the head. As a result, the radial bearing gap and the thrust bearing gap are kept parallel and at an optimum interval.

  As shown in FIG. 4, for example, even when the rotation shaft of the spin coater Sc moves in the thrust direction indicated by the arrow due to weighting, the spring 5 has a gap between the end surface where the thrust bearing surface 3 b is not formed and the housing H. The outer cylinder housing 3 continues to be urged toward the thrust bearing surface 3b while shrinking due to narrowing. As a result, following the movement of the shaft in the thrust direction, the gap between the end surface where the thrust bearing surface 3b is not formed and the housing H is automatically adjusted, and the thrust bearing gap is maintained in parallel and at an optimum interval.

  As shown in FIGS. 3 and 4, the spin coater Sc supplies compressed gas to the radial bearing surface 3 a and the thrust bearing surface 3 b through a tube T from a pressure gas supply source such as a compressor. In the static pressure gas bearing 1 according to the embodiment, the mechanism for supplying the compressed gas is provided in the outer cylindrical housing 3 that is disposed to face the inner peripheral surface of the housing H that is a fixed portion. As described above, since the mechanism for supplying the compressed gas is provided on the side of the casing that is disposed to face the fixed portion, the structure of the static pressure gas bearing 1 can be simplified.

  The spin coater Sc to which the hydrostatic gas bearing 1 according to the embodiment is attached can be easily obtained by simply inserting the hydrostatic gas bearing 1 assembled into a fitting portion of the housing H even if the accuracy of the apparatus is insufficient. Since it is attached, a static pressure gas bearing can be used in a wide range of devices as well as a high-precision device as in the prior art. Moreover, in the spin coater Sc to which the static pressure gas bearing 1 according to the embodiment is attached, the spin coater Sc rotates stably because the alignment is automatically performed with respect to insufficient accuracy of the apparatus or a change in accuracy.

  Subsequently, a static pressure gas bearing according to another embodiment of the present invention will be described in detail with reference to the drawings as appropriate. FIG. 5 is a perspective view of a hydrostatic gas bearing according to another embodiment, and FIG. 6 is an exploded perspective view of a hydrostatic gas bearing according to another embodiment.

  As shown in FIG. 5, the hydrostatic gas bearing 11 according to another embodiment includes an inner cylinder housing 12 that is disposed to face the outer peripheral surface of the shaft, and an outer cylinder housing that is disposed to face the inner peripheral surface of the housing. 13. And the inner cylinder housing | casing 12 is equipped with the 1st elastic body 14 cyclically | annularly in the inner peripheral surface, and the 2nd elastic body 15 in the end surface.

  As shown in FIG. 6, the inner cylindrical housing 12 is a cylindrical member, and has a radial bearing surface 12a made of a porous material on the outer peripheral surface thereof, and a thrust bearing surface 12b made of a porous material on one end surface thereof. Is formed. In addition, compressed gas is supplied to the radial bearing surface 12a and the thrust bearing surface 12b on the end surface (corresponding to the surface on the back side with respect to the thrust bearing gap) where the thrust bearing surface 12b is not formed in the inner cylindrical housing 12. A compressed gas supply hole 12c is formed.

  The inner cylinder housing 12 is provided with a first elastic body 41, in this case an O-ring 41, on the inner peripheral surface of the inner cylinder housing 12. In addition, the inner cylinder housing 12 is provided with a plurality of second elastic bodies 51, here, springs 51 on the circumference of the end face on the end face where the thrust bearing surface 12b is not formed.

  The outer cylinder housing 13 includes an outer cylinder 131 that is a cylindrical member, and a flange 132 that is a flange-shaped member disposed on one end surface thereof. The outer cylinder 131 is configured to face the radial bearing surface 12a formed in the inner cylinder housing 12 with a radial bearing gap. Further, the flange 132 is configured to face the thrust bearing surface 12b formed in the inner cylinder housing 12 with a thrust bearing gap.

  The static pressure gas bearing 11 configured as described above is assembled in a state where the inner cylindrical housing 12 and the outer cylindrical housing 13 adjust the radial bearing gap, and is assembled into an assembly part. The static pressure gas bearing 11 is attached to the apparatus by inserting the pre-assembled static pressure gas bearing 11 into the fitting portion of the housing at the assembly site of the static pressure gas bearing 11.

  FIG. 7 is an overall perspective view of a guide roll device to which a static pressure gas bearing 11 according to another embodiment is attached. As shown in FIG. 7, the static pressure gas bearing 11 is inserted into fitting portions of housings provided at both ends of the guide roll device G and attached to the guide roll device G.

  In the guide roll device G, the compressed gas is supplied from a compressed gas supply source such as a compressor to the static pressure gas bearing 11 through the tube T, so that the static pressure gas bearing 11 holds the support shaft S in a non-contact state. It is configured as follows. In the guide roll device G, for example, when the sheet material is conveyed in the arrow direction, the guide roll member G ′ is rotated in synchronization with the traveling speed of the sheet material by the frictional force received from the sheet material. The sheet material is conveyed to various apparatuses while applying tension to the material.

  FIG. 8 is a cross-sectional view of a main part of a guide roll device G to which a static pressure gas bearing 11 according to another embodiment is attached, and FIG. 9 is a guide roll to which the static pressure gas bearing 11 according to another embodiment is attached. It is sectional drawing which shows the mode of the self-alignment of the apparatus G.

  As shown in FIG. 8, in the static pressure gas bearing 11 according to another embodiment, the inner cylindrical housing 12 faces the outer peripheral surface of the support shaft S, and the outer cylindrical housing 13 faces the inner peripheral surface of the housing H. In this state, it is attached to the guide roll device G.

  The static pressure gas bearing 11 includes a first elastic body 41, here an O-ring 41, on the inner peripheral surface of the inner cylinder housing 12 (corresponding to the surface on the back side with respect to the radial bearing gap). 12 is provided in contact with the inner cylinder housing 12 and the support shaft S.

  Further, the static pressure gas bearing 11 has a second elastic body 51 on the end surface (corresponding to the back surface with respect to the thrust bearing gap) where the thrust bearing surface 12b of the inner cylinder housing 12 is not formed. Then, the spring 51 is inserted into a concave portion formed in the inner cylinder housing 12 in a state where the spring 51 is pressed and contracted by the inner cylinder housing 12 and the housing H.

  In the static pressure gas bearing 11, a mechanism for supplying compressed gas is provided in the inner cylinder housing 12 that is disposed to face the outer peripheral surface of the support shaft S that is a fixed portion. As described above, since the mechanism for supplying the compressed gas is provided on the side of the casing that is disposed to face the fixed portion, the structure of the static pressure gas bearing 11 can be simplified.

  In the static pressure gas bearing 11 configured as described above, as shown in FIG. 9, the guide roll member G ′ (see FIG. 7) bends by its own weight and supports the guide roll member G ′ (housing H in FIG. 9). When a force is applied in a direction deviating from a right angle direction in a direction in which the angle with the shaft S changes, the O ring 41 and the springs 51a and 51b are deformed by the force, and the radial bearing clearance and the thrust bearing surface clearance are parallel and optimal. Is kept at a proper interval.

  More specifically, for example, when the guide roll member G ′ bends downward, a force is applied to the left end portion of the guide roll member G ′ and the static pressure gas bearing 11 in the direction indicated by the arrow. At this time, the O-ring 41 is crushed by the applied force while sliding in the direction indicated by the arrow.

  At this time, since the gap between the inner cylinder housing 12 and the housing H is widened, the spring 51a is weakened and stretched. On the other hand, since the gap between the inner cylinder housing 12 and the housing H is narrowed, the spring 51b has a compressive force that is reduced.

  In this way, the O-ring 41 is deformed while sliding, and the springs 51 a and 51 b expand and contract so as not to hinder the movement of the inner cylinder housing 12. And the inner cylinder housing | casing 12 follows a change of the angle of the housing H and the support shaft S, and moves so that a head may be shaken continuously. As a result, the radial bearing gap is kept parallel and at an optimum spacing.

  Further, while the spring 51a is extended and the spring 51b is contracted, the inner cylinder housing 12 is continuously urged toward the thrust bearing surface 12b. As a result, the thrust bearing gap is kept parallel and at an optimal spacing.

  Further, when the guide roll member G ′ is bent, the guide roll member G ′ is pulled to the center in the thrust direction. At this time, since the gap between the inner cylinder housing 12 and the housing H is widened, the spring 51 is weakened and stretched. The spring 51 continues to urge the inner cylinder housing 12 toward the thrust bearing surface 12b while extending. As a result, the thrust bearing gap is kept parallel and at an optimal spacing.

  In the guide roll device G to which the hydrostatic gas bearing 11 according to another embodiment is attached, the radial bearing gap and the thrust bearing gap are maintained in parallel and at an optimum interval even when the guide roll member G ′ is bent. The roll member G ′ rotates stably.

  As mentioned above, although embodiment of this invention was described, this invention is not limited to the said embodiment. For example, the first elastic bodies 4 and 41 according to the present invention are not limited to O-rings, and may be springs. Furthermore, a spherical seat that plays the same role as the elastic body may be used. The second elastic bodies 5 and 51 according to the present invention are not limited to coil springs, and may be leaf springs. In addition to the spring, rubber may be used.

  Further, the position where the first elastic bodies 4 and 41 are provided is not limited to the surface opposite to the radial bearing surfaces 3a and 12a as in the above embodiment, as long as it is a surface on the back side with respect to the radial bearing gap.

  In this invention, the surface on the back side with respect to the radial bearing gap refers to the surface opposite to the surface forming the radial gap. Further, in the present invention, the surface on the back side with respect to the thrust bearing gap refers to the surface opposite to the surface forming the thrust gap. Therefore, for example, in the static pressure gas bearing 1, the first elastic body 4 may be provided between the inner peripheral surface of the inner cylinder housing 2 and the shaft. In this case, the second elastic body 5 is provided on the inner cylinder housing 2 on the surface opposite to the surface forming the thrust gap.

DESCRIPTION OF SYMBOLS 1,11 Static pressure gas bearing 2,12 Inner cylinder housing | casing 3,13 Outer cylinder housing | casing 3a, 12a Radial bearing surface 3b, 12b Thrust bearing surface 4,41 1st elastic body (O-ring)
5, 51 Second elastic body (spring)

Claims (2)

An inner cylinder housing configured to have an inner cylinder opposed to the outer peripheral surface of the shaft and a flange disposed at one end surface thereof ; and an outer cylinder housing disposed to oppose the inner peripheral surface of the housing; made, the inner cylinder or the radial bearing surface provided on the opposing surfaces of the outer cylindrical casing, a thrust bearing surface provided on the opposing surfaces of the flange or outer cylindrical casing, which is formed between the bearing surfaces In a hydrostatic gas bearing that supplies compressed gas to the radial bearing gap and the thrust bearing gap and holds the shaft and the housing in a non-contact state,
A first elastic body is provided on the back surface with respect to the radial bearing gap,
A static pressure gas bearing, comprising a second elastic body in a casing on the back side with respect to the thrust bearing gap and provided with the first elastic body. An outer cylinder housing which is arranged to be opposed to the outer peripheral surface of the shaft, an outer cylinder which is arranged to be opposed to the inner circumferential surface of the housing, and a flange which is arranged on one end surface thereof ; A radial bearing surface is provided on the mutually facing surfaces of the inner cylinder housing or outer cylinder, and a thrust bearing surface is provided on the mutually facing surfaces of the inner cylinder housing or flange, and the radial formed between these bearing surfaces In the hydrostatic gas bearing that supplies compressed gas to the bearing gap and the thrust bearing gap and holds the shaft and the housing in a non-contact state,
A first elastic body is provided on the back surface with respect to the radial bearing gap,
A static pressure gas bearing, comprising a second elastic body in a casing on the back side with respect to the thrust bearing gap and provided with the first elastic body.

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