JP6500335B2 - Static pressure gas bearing rotation guide device - Google Patents

Description

  The present invention relates to a static pressure gas bearing rotation guide device.

  A static pressure gas bearing is known as a support structure for supporting a rotating shaft. The static pressure gas bearing can rotatably support the rotating shaft without contact. For example, Patent Document 1 discloses a hydrostatic fluid bearing including a bearing housing having a radial bearing portion and a thrust bearing portion, and hydrostatic bearing pads held by the radial bearing portion and the thrust bearing portion of the bearing housing, respectively. Is described.

Japanese Patent Laid-Open No. 5-71535

  In the technique of Patent Document 1, members such as a radial bearing, a thrust bearing, and a porous cylindrical pad are provided all around the circumferential direction of the rotation shaft. Therefore, in the case of using the technology of Patent Document 1, when the size in the radial direction of the rotating shaft is increased, members such as radial bearings, thrust bearings and cylindrical pads become larger as the rotating shaft is increased. However, there is a limit to the processing accuracy of the member and the stability of the porosity of the porous material. For this reason, when the rotating shaft is enlarged, the pressure acting on the rotating shaft may become uneven in the circumferential direction, and the bearing load capacity and the bearing rigidity may be reduced.

  The present invention has been made in view of the above, and provides a static pressure gas bearing rotation and guiding device capable of uniforming pressure acting on a rotating member in the circumferential direction and suppressing reduction in bearing load capacity and bearing rigidity. The purpose is

  In order to solve the problems described above and achieve the object, the static pressure gas bearing rotary guide device is a rotary member that is a disk-shaped member that rotates around an axis, a housing, and a porous material, and the housing And a plurality of air pads provided side by side in the circumferential direction of the rotating member and injecting gas toward the rotating member, and a plurality of static pressure gas bearings disposed at equal intervals in the circumferential direction of the rotating member; , And.

  Thereby, even when the rotating member is enlarged, the enlargement of the static pressure gas bearing is suppressed. For this reason, the magnitude | size of each member with which a static pressure gas bearing is equipped is less than fixed size, and the fall of the processing precision of each member is suppressed. In addition, since a plurality of air pads are provided in the housing, upsizing of the air pads is suppressed. Therefore, even when the rotating member is enlarged, the stability of the porosity of the air pad, which is a porous material, can be easily maintained. Thereby, the pressure acting on the rotating member is likely to be uniform in the circumferential direction. Therefore, the static pressure gas bearing rotation and guiding device according to the present invention can suppress the lowering of the bearing load capacity and the bearing rigidity.

  As a desirable mode of the present invention, the housing is provided on an inner flow passage which is a flow passage provided therein, a plurality of first recesses provided on a surface facing the rotating member, and a bottom surface of the first recess. And a second recess connected to the internal flow passage, the air pad being fitted in the first recess, the inner flow passage and the second Preferably, the gas is supplied through the recess. Thus, the gas introduced into the internal flow path contacts the wide area of the air pad through the second recess. For this reason, the gas is likely to be ejected from the entire air pad. Therefore, the static pressure gas bearing rotation guide device can suppress the variation due to the position of the force applied to the rotating member by the gas ejected from the air pad. Therefore, the static pressure gas bearing rotation guide device can improve the stability of the rotation movement of the rotation member.

  As a desirable mode of the present invention, a part of air pads among the plurality of air pads are surfaces from which gas is ejected toward the curved side surface of the rotating member and gas of the air pad opposed to the side surface is ejected. It is preferable that the jet surface is a curved surface along the side surface. Thereby, the gap generated between the jet surface and the side surface tends to be constant. Therefore, the static pressure gas bearing rotation guide device can suppress the variation due to the position of the force applied to the rotating member by the gas ejected from the air pad. Therefore, the static pressure gas bearing rotation guide device can improve the stability of the rotation movement of the rotation member.

  As a desirable mode of the present invention, it is preferred to have an annular case, and the above-mentioned housing is rockably supported by the above-mentioned case. As a result, even if the radial position of the rotary member changes, or the tilt with respect to the axis of the rotary member changes, the housing can swing, so the rotary member and the air pad do not contact. It is easy to maintain the state. Therefore, the static pressure gas bearing rotation guide device can further suppress the decrease in the bearing load capacity and the bearing rigidity.

  According to the present invention, it is possible to provide a static pressure gas bearing rotation and guide device capable of making the pressure acting on the rotating member circumferentially uniform and suppressing the decrease in bearing load capacity and bearing rigidity.

FIG. 1 is a plan view showing a static pressure gas bearing rotation and guiding device according to the present embodiment excluding an upper surface portion of a housing. FIG. 2 is a view showing a cross section A-A 'in FIG. FIG. 3 is a view showing the first housing and the first air pad viewed from the first end face side of the rotation member. FIG. 4 is a view showing the third housing and the third air pad viewed from the side of the rotating member. FIG. 5 is a view showing a cross section B-B 'in FIG. FIG. 6 is a cross-sectional view of a static pressure gas bearing rotary guide according to a modification taken along a plane including the axis of the rotary member.

  A mode (embodiment) for carrying out the present invention will be described in detail with reference to the drawings. The present invention is not limited by the contents described in the following embodiments. Further, the components described below include those which can be easily conceived by those skilled in the art and those which are substantially the same. Furthermore, the components described below can be combined as appropriate.

(Embodiment)
FIG. 1 is a plan view showing a static pressure gas bearing rotation and guiding device according to the present embodiment excluding an upper surface portion of a housing. FIG. 2 is a view showing a cross section AA 'in FIG. FIG. 3 is a view showing the first housing and the first air pad viewed from the first end face side of the rotation member. FIG. 4 is a view showing the third housing and the third air pad viewed from the side of the rotating member. FIG. 5 is a view showing a cross section BB 'in FIG. As shown in FIGS. 1 and 2, for example, the static pressure gas bearing rotation guide device 1 includes a housing 10, a rotating member 6, three first static pressure gas bearings ab1, and three second static pressure gas bearings. ab2 and three third static pressure gas bearings ab3. The static pressure gas bearing rotation guide device 1 is used, for example, as a mechanism for rotating a wafer to be inspected in a wafer inspection device. The first static pressure gas bearing ab1, the second static pressure gas bearing ab2, and the third static pressure gas bearing ab3 may not necessarily be three, but may be two, respectively. There may be four or more.

  As shown in FIG. 1, the housing 10 is annular. Further, as shown in FIG. 2, the housing 10 includes an upper surface portion 101, a bottom surface portion 102, and a side surface portion 103. The upper surface portion 101 is a ring-shaped plate-like member. The bottom surface portion 102 is a ring-shaped plate member parallel to the top surface portion 101. The side surface portion 103 is a member that connects the top surface portion 101 and the bottom surface portion 102. For example, in the present embodiment, the housing 10 is disposed such that the top surface portion 101 and the bottom surface portion 102 are orthogonal to the vertical direction.

  The rotating member 6 is a disk-shaped member that rotates around the axis Z. For example, in the present embodiment, the axis Z is orthogonal to the horizontal plane. The rotating member 6 is made of, for example, stainless steel. The rotating member 6 has a first end surface 61 which is a surface orthogonal to the axis Z, a second end surface 62 which is a surface parallel to the first end surface 61, and a side surface which is a surface which is circular when viewed from the axis Z direction. And 63. The side surface 63 is a curved surface, and connects the radially outer end of the first end surface 61 and the radially outer end of the second end surface 62. Further, the rotating member 6 includes a through hole 6h penetrating in the axis Z direction, and an annular groove 65 provided on the inner peripheral surface of the through hole 6h. The groove 65 is formed, for example, by cutting the inner peripheral surface of the through hole 6 h. Thereby, the rotation member 6 is lightweight compared with the case where it is a solid member. The rotating member 6 also includes a plurality of mounting holes 61 h penetrating from the first end face 61 toward the groove 65 and a plurality of mounting holes 62 h penetrating from the second end face 62 toward the groove 65. The mounting holes 61 h and the mounting holes 62 h are, for example, arranged at equal intervals in the circumferential direction of the rotating member 6. For example, a machine base (chuck) for holding an object to be inspected such as a wafer is fixed to the rotating member 6 using a fixing tool such as a bolt and the mounting holes 61 h and 62 h.

  The rotating member 6 may be formed by assembling a member forming the first end face 61, a member forming the second end face 62, and a member forming the side face 63. When the separate member is assembled in this manner to form the rotary member 6, the gap between the member forming the first end face 61 and the member forming the second end face 62 is the groove 65.

  As shown in FIG. 1, the three first static pressure gas bearings ab1 are arranged at equal intervals in the circumferential direction of the rotating member 6. As shown in FIG. 2, the first static pressure gas bearing ab 1 includes a first housing 4 and a first air pad 5.

  The first housing 4 is disposed to face the first end face 61. The first housing 4 is formed of, for example, stainless steel. The shape of the first housing 4 as viewed from the first end face 61 is, for example, a fan shape. As shown in FIG. 2, the first housing 4 is provided with a socket portion 48 which is a spherical recess on the surface opposite to the surface facing the first end surface 61. The spherical tip end of the ball stud b is fitted in the socket portion 48. The ball stud b passes through the top surface 101 and is positioned by the locking nut n. Thereby, the first housing 4 is swingably supported by the upper surface portion 101. The position of the tip of the ball stud b can be adjusted by loosening the locking nut n.

  The first air pad 5 is a plate-like porous material made of, for example, graphite, and is supported by the first housing 4. As shown in FIG. 2, the first housing 4 is provided with a first recess 49 on the surface facing the first end face 61. The first air pad 5 is fitted in the first recess 49. The first air pad 5 is fixed to the first recess 49 by, for example, an adhesive. As shown in FIG. 3, for example, five first air pads 5 are fixed to each first housing 4. The five first air pads 5 are arranged at equal intervals in the circumferential direction of the rotating member 6, for example. The first air pad 5 may be fixed to the first recess 49 by a bolt or the like. In addition, the number of first air pads 5 fixed to each first housing 4 may not be five, and may be four or less or six or more.

  As shown in FIG. 1, the three second static pressure gas bearings ab2 are arranged at equal intervals in the circumferential direction of the rotating member 6. The second static pressure gas bearing ab2 is, for example, disposed so as to overlap the first static pressure gas bearing ab1 when viewed from the axial direction of the rotary member 6. As shown in FIG. 2, the second static pressure gas bearing ab 2 includes a second housing 7 and a second air pad 8.

  The second housing 7 is disposed to face the second end face 62. The second housing 7 is formed of, for example, stainless steel. The shape of the second housing 7 as viewed from the second end face 62 is, for example, a fan shape. As shown in FIG. 2, the second housing 7 is provided with a socket portion 78 which is a spherical recess on the surface opposite to the surface facing the second end surface 62. The spherical tip end of the ball stud b is fitted in the socket portion 78. The ball stud b passes through the bottom portion 102 and is positioned by the locking nut n. Thereby, the second housing 7 is swingably supported by the bottom surface portion 102.

  The second air pad 8 is a plate-like porous material formed of, for example, graphite, and is supported by the second housing 7. The second housing 7 is provided with a first recess 79 on the surface facing the second end face 62. The second air pad 8 is fitted in the first recess 79. The second air pad 8 is fixed to the first recess 79 by, for example, an adhesive. The second air pads 8 are fixed, for example, five to each second housing 7. The five second air pads 8 are arranged at equal intervals in the circumferential direction of the rotating member 6, for example. The second air pad 8 may be fixed to the first recess 79 by a bolt or the like. Further, the number of second air pads 8 fixed to each second housing 7 may not be five, and may be four or less or six or more.

  As shown in FIG. 1, the three third static pressure gas bearings ab3 are arranged at equal intervals in the circumferential direction of the rotating member 6. The third static pressure gas bearing ab3 is disposed, for example, so that the circumferential positions of the first static pressure gas bearing ab1 and the second static pressure gas bearing ab2 and the rotating member 6 are the same. As shown in FIG. 2, the third static pressure gas bearing ab 3 includes the third housing 2 and the third air pad 3.

  The third housing 2 is disposed to face the side surface 63. The third housing 2 is formed of, for example, stainless steel. As shown in FIG. 4, the shape of the third housing 2 as viewed from the side surface 63 is, for example, a rectangle. As shown in FIG. 2, the third housing 2 is provided with a socket portion 28 which is a spherical recess on the surface opposite to the surface facing the side surface 63. The spherical tip end of the ball stud b is fitted in the socket portion 28. The ball stud b passes through the side portion 103 and is positioned by the locking nut n. Thereby, the third housing 2 is swingably supported by the side surface portion 103.

  The third air pad 3 is a plate-like porous material formed of, for example, graphite, and is supported by the third housing 2. The third housing 2 is provided with a first recess 29 on the surface facing the side surface 63. The third air pad 3 is fitted in the first recess 29. The third air pad 3 is fixed to the first recess 29 by, for example, an adhesive. As shown in FIG. 4, for example, five third air pads 3 are fixed to each third housing 2. The five third air pads 3 are arranged at equal intervals in the circumferential direction of the rotating member 6, for example. The third air pad 3 may be fixed to the first recess 29 by a bolt or the like. In addition, the number of third air pads 3 fixed to the respective third housings 2 may not be five, and may be four or less or six or more.

  As shown to FIG.4, 5, the 3rd housing 2 is equipped with the internal flow path 21 which is a flow path provided in an inside. One end of the internal flow passage 21 opens to the outside of the third housing 2. The third housing 2 is provided with a second recess 23 smaller than the first recess 29 provided on the bottom surface of the first recess 29 and connected to the internal flow passage 21. For example, the second recess 23 includes a rectangular portion 23a whose shape seen from the side surface 63 is rectangular and a cross portion 23b whose shape seen from the side surface 63 is a cross. The cross portion 23 b is disposed inside the rectangular portion 23 a. The end of the cross portion 23b is connected to the middle portion of each of the four sides of the rectangular portion 23a.

  As shown in FIG. 5, the third air pad 3 includes a jet surface 31 which is a surface facing the side surface 63 of the rotary member 6 and a back surface 32 which is a surface opposite to the jet surface 31. The ejection surface 31 has, for example, a curved surface shape along the side surface 63 of the rotating member 6 to which the third air pad 3 faces. Thereby, the gap G generated between the jet surface 31 and the side surface 63 is constant. For example, in the present embodiment, the gap G is about 10 μm. The back surface 32 is a flat surface and is in contact with the bottom surface of the first recess 29.

  Compressed air is introduced into the internal flow passage 21 from the outside. The compressed air introduced into the internal flow passage 21 contacts the wide area of the back surface 32 of the third air pad 3 through the second recess 23. Since the third air pad 3 is a porous material, the compressed air moves inside the third air pad 3 from the back surface 32 side to the ejection surface 31 side. The compressed air diffuses through the pores in the third air pad 3, and thus jets out from the entire jet surface 31 toward the side surface 63 of the rotary member 6. For this reason, a radially inward force is applied to the rotating member 6 by the third static pressure gas bearing ab3. The three third static pressure gas bearings ab3 are equally disposed in the circumferential direction of the rotary member 6 as described above. Thereby, the forces applied to the rotating member 6 from the three third static pressure gas bearings ab3 are balanced. For this reason, the position of the radial direction of rotation member 6 is regulated, when rotation member 6 and the 3rd air pad 3 do not contact. Further, even if the radial position of the rotary member 6 changes, the third housing 2 can swing, so the state in which the rotary member 6 is not in contact with the third air pad 3 can be easily maintained.

  Further, as shown in FIG. 3, the first housing 4 includes an internal flow passage 41 corresponding to the internal flow passage 21 of the third housing 2 and a second recess 43 corresponding to the second recess 23 of the third housing 2. And. The compressed air is introduced into the first air pad 5 through the internal flow passage 41 and the second recess 43, and the compressed air is jetted from the first air pad 5 toward the first end face 61. Therefore, a downward force in the vertical direction is applied to the rotating member 6 by the first static pressure gas bearing ab1. The size of the gap between the surface of the first air pad 5 from which the compressed air is jetted and the first end surface 61 is approximately the same as the size of the gap G described above.

  Further, the second housing 7 includes, for example, an internal flow passage having the same shape as the internal flow passage 41 and a second recess having the same shape as the second recess 43. The compressed air is introduced to the second air pad 8 through the internal flow passage and the second recess in the second housing 7, and the compressed air is jetted from the second air pad 8 toward the second end face 62. Therefore, a vertically upward force is applied to the rotating member 6 by the second static pressure gas bearing ab2. Further, the size of the gap between the surface of the second air pad 8 from which the compressed air is jetted and the second end surface 62 is approximately the same as the size of the gap G described above.

  The amount of compressed air ejected from the first air pad 5 and the amount of air ejected from the second air pad 8 can be independently adjusted. Thereby, the force applied to the rotating member 6 by the second static pressure gas bearing ab2 is balanced with the combined force of the force applied to the rotating member 6 by the first static pressure gas bearing ab1 and the gravity applied to the rotating member 6. Therefore, the axial position of the rotary member 6 is regulated in a state where the rotary member 6 is not in contact with the first air pad 5 and the second air pad 8. Further, since the first static pressure gas bearing ab1 and the second static pressure gas bearing ab2 are disposed at equal intervals in the circumferential direction of the rotary member 6, it is easy to regulate the inclination of the rotary member 6 with respect to the axis Z. In addition, even if the inclination of the rotation member 6 with respect to the axis Z changes, the first housing 4 and the second housing 7 can swing, so the rotation member 6 can be used as the first air pad 5 and the second air pad 8. It is easy to maintain the non-contact state.

  The first static pressure gas bearing ab1, the second static pressure gas bearing ab2, and the third static pressure gas bearing ab3 are each three. Thereby, compared with the case where the first static pressure gas bearing ab1, the second static pressure gas bearing ab2, and the third static pressure gas bearing ab3 are each two, the static pressure gas bearing rotation guide device 1 is a rotating member It becomes easy to regulate the position of the axis 6 in the direction of the axis Z and the inclination of the rotary member 6 with respect to the axis Z. Therefore, the static pressure gas bearing rotation guide device 1 can improve the stability of the rotational movement of the rotation member 6.

  Further, the second static pressure gas bearing ab2 is disposed so as to overlap the first static pressure gas bearing ab1 when viewed from the direction of the axis Z of the rotary member 6. Thereby, the point of action of the force applied to the rotating member 6 by the first static pressure gas bearing ab1 and the point of action of the force applied to the rotating member 6 by the second static pressure gas bearing ab2 are in the circumferential direction of the rotating member 6 It becomes easy to match. Therefore, it is easy to adjust the amount of compressed air ejected from the first air pad 5 and the amount of compressed air ejected from the second air pad 8. Therefore, the static pressure gas bearing rotation guide device 1 can easily maintain the stability of the rotational movement of the rotation member 6.

  Further, the rotating member 6 includes a through hole 6h penetrating in the axis Z direction, and an annular groove 65 provided on the inner peripheral surface of the through hole 6h. Thereby, the rotation member 6 becomes lightweight compared with the case where it is a solid member. For this reason, when rotating the rotation member 6, the inertial force which acts on the rotation member 6 becomes small. Therefore, the static pressure gas bearing rotation guide device 1 can easily control the rotation speed of the rotation member 6.

  The first static pressure gas bearing ab1 and the second static pressure gas bearing ab2 may not necessarily be arranged in the same number. For example, the number of second static pressure gas bearings ab2 may be larger than the number of first static pressure gas bearings ab1. As described above, the force applied to the rotating member 6 by the second static pressure gas bearing ab2 needs to be balanced with the combined force of the force applied to the rotating member 6 by the first static pressure gas bearing ab1 and the gravity applied to the rotating member 6 There is. Therefore, by setting the number of second static pressure gas bearings ab2 to be larger than the number of first static pressure gas bearings ab1, the amount of compressed air ejected from one first air pad 5 and one second air pad 8 can be obtained. The amount of compressed air to be ejected is more uniform. Thereby, the stability of the rotational movement of the rotary member 6 may be improved.

  The rotating member 6, the first housing 4, the second housing 7, and the third housing 2 may not necessarily be formed of stainless steel, and may be formed of another material. However, it is preferable that the rotating member 6, the first housing 4, the second housing 7, and the third housing 2 be formed of a metal having a low coefficient of thermal expansion. The first air pad 5, the second air pad 8, and the third air pad 3 may not necessarily be made of graphite, and may be made of other materials. However, when the first air pad 5, the second air pad 8, and the third air pad 3 are formed of graphite, it is preferable in that the friction with the rotating member 6 is less likely to occur even when contacting the rotating member 6.

  As described above, the static pressure gas bearing rotation guide device 1 includes the rotation member 6 which is a disk-shaped member that rotates around the axis Z. The static pressure gas bearing rotation guide device 1 is a housing (the first housing 4, the second housing 7 or the third housing 2) and a porous material, and is provided in the housing in the circumferential direction of the rotation member 6 to rotate A plurality of static pressure provided with a plurality of air pads (the first air pad 5, the second air pad 8 or the third air pad 3) for jetting the gas toward the member 6, and arranged at equal intervals in the circumferential direction of the rotating member 6. A gas bearing (a first static pressure gas bearing ab1, a second static pressure gas bearing ab2 or a third static pressure gas bearing ab3) is provided.

  Thereby, even when the rotary member 6 is enlarged, the enlargement of the first static pressure gas bearing ab1, the second static pressure gas bearing ab2, and the third static pressure gas bearing ab3 is suppressed. For this reason, the size of each member provided in the first static pressure gas bearing ab1, the second static pressure gas bearing ab2, and the third static pressure gas bearing ab3 remains smaller than a predetermined size, and the processing accuracy of each member decreases. Be suppressed. Therefore, even when the rotating member 6 is large, the static pressure gas bearing rotation guiding device 1 can support the rotating member 6 in a noncontact manner. The phrase “supporting the rotary member 6 in a non-contact manner” means between the first air pad 5 and the rotary member 6, between the second air pad 8 and the rotary member 6, and between the third air pad 3 and the rotary member 6. The position of the rotating member 6 in the Z-direction and the radial direction is restricted by the gas (compressed air) present in the above. That is, “supporting the rotating member 6 in a non-contact manner” means that the rotating member 6 floats in the air by gas (compressed air). In addition, since a plurality of air pads are provided in the housing, upsizing of the air pads is suppressed. For this reason, even when the rotation member 6 is enlarged, stability of the porosity of the air pad which is a porous material can be easily maintained. As a result, the pressure acting on the rotating member 6 is likely to be uniform in the circumferential direction. Therefore, even if the rotating member 6 is large, the static pressure gas bearing rotation and guiding device 1 can suppress the decrease in the bearing load capacity and the bearing rigidity. Here, the bearing load capacity is the maximum load at which the static pressure gas bearing rotation and guide apparatus 1 can support the rotating member 6 in a noncontact manner. With bearing rigidity, when impact or vibration is applied to the rotating member 6 while the rotating member 6 is rotating, the rotating member 6 does not contact the first air pad 5, the second air pad 8 or the third air pad 3 and rotates. It is possible to do it. The unit of bearing stiffness is, for example, [N / μm]. That is, bearing rigidity means the load [N] required to move the rotating member 6 during rotation by 1 μm.

  Further, the housing (the first housing 4, the second housing 7 or the third housing 2) is a flow channel provided inside, and a surface facing the rotating member 6 and an inner flow channel (internal flow channels 21, 41 etc.) A plurality of first recesses (first recesses 29, 49, 79) provided in the second embodiment, and second recesses provided in the bottom surface of the first recess and smaller than the first recesses and connected to the internal flow path And the like. The air pad (the first air pad 5, the second air pad 8, or the third air pad 3) is fitted in the first recess and is supplied with gas through the internal flow path and the second recess. Thus, the gas (compressed air) introduced into the internal flow passage contacts the wide area of the air pad through the second recess. For this reason, gas (compressed air) is likely to be ejected from the entire air pad. Therefore, the static pressure gas bearing rotation guide device 1 can suppress the variation due to the position of the force applied to the rotating member 6 by the gas (compressed air) ejected from the air pad. For this reason, the static pressure gas bearing rotation guide apparatus 1 can improve the stability of the rotational movement of the rotation member 6.

  Further, some of the plurality of air pads (first air pad 5, second air pad 8 or third air pad 3), air pads (third air pad 3) are gas (compressed) toward curved side surface 63 of rotating member 6. The ejection surface 31, which is a surface from which the air (a third air pad 3) of the air pad (third air pad 3) facing the side surface 63 is ejected, has a curved surface along the side surface 63. Thus, the gap G generated between the jet surface 31 and the side surface 63 tends to be constant. Therefore, the static pressure gas bearing rotation guide device 1 can suppress the variation due to the position of the force applied to the rotating member 6 by the gas (compressed air) ejected from the air pad. For this reason, the static pressure gas bearing rotation guide apparatus 1 can improve the stability of the rotational movement of the rotation member 6.

  In addition, the static pressure gas bearing rotation guide device 1 includes an annular case 10, and the housing (the first housing 4, the second housing 7 or the third housing 2) is swingably supported by the case 10 . Thereby, even if the radial position of the rotary member 6 changes, or even if the tilt of the rotary member 6 with respect to the axis Z changes, the housing (the first housing 4, the second housing 7 or Since the third housing 2) can swing, the noncontact state of the rotary member 6 and the air pad (the first air pad 5, the second air pad 8, or the third air pad 3) is easily maintained. Therefore, the static pressure gas bearing rotation and guide apparatus 1 can further suppress the reduction in the bearing load capacity and the bearing rigidity.

(Modification)
FIG. 6 is a cross-sectional view of a static pressure gas bearing rotary guide according to a modification taken along a plane including the axis of the rotary member. The same components as those described in the above-described embodiment are denoted by the same reference numerals, and overlapping descriptions will be omitted.

  The static pressure gas bearing rotation and guide apparatus 1 according to the modification includes a rotation member 6A. The rotation member 6A is a disk-shaped member that rotates around the axis Z. The rotating member 6A is made of, for example, stainless steel. The rotating member 6A has a first end surface 61A that is a surface orthogonal to the axis Z, a second end surface 62A that is a surface parallel to the first end surface 61, and a side surface that is a circular surface when viewed from the axis Z direction. And 63. Further, the rotation member 6A includes a through hole 6hA penetrating in the axis Z direction, and annular grooves 66 and 67 provided on the inner peripheral surface of the through hole 6hA. The rotation member 6A includes a fixing portion 64 between the groove 66 and the groove 67. The fixing portion 64 has a plate shape orthogonal to the axis Z, and includes a plurality of attachment holes 64 h penetrating in the axis Z direction. The mounting holes 64h are arranged at equal intervals in the circumferential direction of the rotating member 6A, for example. For example, a machine base (chuck) holding an object to be inspected such as a wafer is fixed to the fixing portion 64 using a fixing tool such as a bolt and the mounting hole 64 h.

As a result, the rotation member 6A does not have to include the mounting holes 61h and 62h described in the embodiment. Therefore, the areas of the first end face 61A and the second end face 62A can be smaller than the areas of the first end face 61 and the second end face 62 in the above-described embodiment.
In addition, since the fixed portion 64 bears the force due to the weight of the inspection object such as a wafer, there is a possibility that the thickness of the portion other than the fixed portion 64 in the rotating member 6A may become thin. As a result, there is a possibility that the rotation member 6A may be lighter than the rotation member 6 of the above-described embodiment. For this reason, there is a possibility that the inertial force acting on the rotating member 6A may be reduced when the rotating member 6A is rotated. Therefore, there is a possibility that the static pressure gas bearing rotation guide device 1 according to the modification can easily control the rotation speed of the rotation member 6A.

DESCRIPTION OF SYMBOLS 1 Static pressure gas bearing rotation guide apparatus 10 Housing | casing 101 Upper surface part 102 Bottom part 103 Side part 2 3rd housing 21 Internal flow path 23 2nd recessed part 23a Rectangular part 23b Cross part 28 Socket part 29 1st recessed part 3 3rd air pad 31 Ejection surface 32 back surface 4 first housing 41 internal flow passage 43 second concave portion 48 socket portion 49 first concave portion 5 first air pad 6, 6A rotation member 6h, 6hA through hole 61, 61A first end face 61h mounting hole 62, 62A 2 end face 62 h mounting hole 63 side 64 fixing portion 64 h mounting holes 65, 66, 67 groove 7 second housing 78 socket portion 79 first recess 8 second air pad ab1 first static pressure gas bearing ab2 second static pressure gas bearing ab3 first 3 Static pressure gas bearing b Ball stud G Clearance n Locking nut

Claims (3)

A rotating member that is a disk-shaped member that rotates around an axis;
A plurality of sets of hydrostatic gas bearings which are the side surface, the first end surface and the second end surface of the rotating member and which are arranged at equal intervals along the circumferential direction;
Equipped with
The static pressure gas bearing is provided with a housing, and a porous material, and a plurality of air pads provided in the housing in the circumferential direction of the rotating member so as to eject gas toward the rotating member.
The housing is smaller than an internal flow passage which is a flow passage provided therein, a plurality of first recesses provided on a surface facing the rotating member, and a first recess provided on a bottom surface of the first recess. A recess, and a second recess connected to the internal flow path;
The air pad is fitted in the first recess and is supplied with the gas through the internal flow path and the second recess.
Said second recess has a rectangular section shape viewed from the surface of the rotating member facing the air pad is rectangular and circular, the shape viewed from the surface of the rotating member facing the air pad is cruciform cross With the department,
The rectangular portion and the cross portion have a concave shape,
An end portion of the cross portion is connected to an intermediate portion of each of four sides of the rectangular portion. A static pressure gas bearing rotation and guide device. Some of the plurality of air pads eject gas toward the curved side surface of the rotating member,
The static pressure gas bearing rotation guide device according to claim 1, wherein an ejection surface which is a surface from which the gas of the air pad opposed to the side surface is ejected has a curved surface shape along the side surface. Equipped with an annular housing,
The static pressure gas bearing rotation guide device according to claim 1, wherein the housing is swingably supported by the housing.

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