JP2010096311A - Hydrostatic bearing pad, linear guide apparatus, and rotation guide apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hydrostatic bearing pad that stably supports an object to be supported irrespective of the mass of the object be supported by controlling static pressure corresponding to the change of the mass of the object to be supported. <P>SOLUTION: In the hydrostatic bearing pad 110, a first gas supply groove 51 and a second gas supply groove 52 are independent from each other and unconnected to each other. Pressurized gas to be supplied to a bearing surface 21 is independently supplied from the first gas supply groove 51 through a first gas supply pipe 41 as a pressurized gas supply part and from the second gas supply groove 52 through a second gas supply pipe 42 as a pressurized gas supply part. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a hydrostatic bearing pad, a linear motion guide device, and a rotation guide device. More specifically, the present invention relates to a supported body by controlling a static pressure according to a change in mass of a supported body to be supported. The present invention relates to a hydrostatic bearing pad that stably supports the supported body regardless of its mass, and a linear motion guide device and a rotation guide device using the hydrostatic bearing pad described above.

  In precision machine tools and semiconductor exposure equipment, pad type is used as a bearing to support a movable part (supported body) that performs positioning for high-precision positioning of processing tools and workpieces and prevention of wear of the support part. The hydrostatic air bearing (hydrostatic bearing pad) is used. The hydrostatic bearing pad is attached to at least one of a pair of opposed surfaces including a movable part and a fixed part constituting a precision machine tool and a semiconductor exposure apparatus. Then, the static pressure bearing pad is applied to the surface facing the static pressure bearing pad by utilizing the static pressure of jetting pressurized gas from the nozzle or the throttle hole of the hydrostatic bearing pad toward the surface facing the static pressure bearing pad. Keep up the surface. Based on the above principle, the hydrostatic bearing pad supports the movable part or the fixed part, which is a supported body, in a non-contact state.

A conventional hydrostatic bearing pad is composed of a bearing member and a housing for housing the bearing member as disclosed in, for example, Japanese Patent Laid-Open No. 63-23310 (hereinafter referred to as “Patent Document 1”). Then, from a pressurized gas supply source such as a compressor (not shown) through a supply pipe (“supply hole” in Patent Document 1) provided inside the housing, the housing stores a bearing member (in Patent Document 1). Pressurized gas is supplied to the “housing”. And the pressurized gas supplied through the air supply groove ("air groove" in patent document 1) concentrically arranged on the surface of the concave portion of the housing facing the bearing member is made porous. Introduced into a bearing member made of material. The pressurized gas is dispersed in a large number of holes (gap) in the bearing member made of a porous material, and is ejected from the large number of gaps to the outside of the bearing member (toward the surface facing the hydrostatic bearing pad). Based on the above principle, the static pressure bearing pad is kept floating with respect to the surface of the hydrostatic bearing pad facing the bearing member, and the supported body is supported by the static pressure bearing pad.
JP 63-23310 A

  In the hydrostatic bearing pad disclosed in Patent Document 1 described above, a plurality of concentric air supply grooves arranged in the concave portion of the housing pressurize almost uniformly to a region facing the air supply groove in the bearing member. Supply gas. This is because an air supply groove that intersects a plurality of air supply grooves arranged concentrically substantially perpendicularly (formed in the radial direction) is supplied with a plurality of concentric circles of pressurized gas supplied from an air supply pipe. This is because the air is supplied almost uniformly to all of the air supply grooves.

  Here, the mass of the supported body supported by the hydrostatic bearing pad varies depending on the type of the supported body and the type of the load loaded on the supported body. Therefore, the hydrostatic bearing pad needs to change (control) the pressure of the pressurized gas in order to cope with the change in mass described above. For example, when supporting a supported body holding a large load, by increasing the pressure of the pressurized gas supplied to the hydrostatic bearing pad, the hydrostatic bearing pad is opposed to the surface facing the bearing member. It is necessary to increase the pressure of the pressurized gas to be ejected to increase the flying height with respect to the surface facing the hydrostatic bearing pad. However, for example, if only the supply pressure of the pressurized gas is increased in order to support a large load, self-excited vibration is generated in the hydrostatic bearing pad, and the hydrostatic bearing pad may cause unstable support. For this reason, the supply pressure of the pressurized gas cannot be increased without limitation, and the range in which the pressure of the pressurized gas can be changed is small. As a result, the adjustable range for the flying height with respect to the surface opposed to the hydrostatic bearing pad is also reduced, so that it is necessary to limit the mass of the load on the supported body.

  The present invention has been made in view of the above problems, and the object thereof is to stably support regardless of the mass of the supported body by controlling the static pressure according to the change in the mass of the supported body to be supported. A hydrostatic bearing pad is provided. Another object of the present invention is to provide a linear motion guide device and a rotation guide device using the hydrostatic bearing pad.

  A hydrostatic bearing pad according to the present invention is a hydrostatic bearing pad that supports a supported body using a pressurized gas, and includes a bearing member having a bearing surface and a housing for holding the bearing member. . In the connecting portion between the bearing member and the housing, a plurality of independent air supply grooves for supplying the pressurized gas to the bearing surface are formed in at least one of the bearing member and the housing. . The hydrostatic bearing pad further includes a pressurized gas supply unit that supplies the pressurized gas independently to each of the plurality of air supply grooves.

  A plurality of independent air supply grooves formed in the hydrostatic bearing pad according to the present invention are independent (discontinuous) from each other. For this reason, for example, by providing a pressurized gas supply unit that supplies pressurized gas independently to each of the plurality of air supply grooves, the supply pressure of the pressurized gas among the plurality of air supply grooves is reduced. By controlling only the pressurized gas supply unit that supplies pressurized gas to the air supply groove to be changed, the supply pressure of the pressurized gas supplied to the bearing member can be controlled more finely. For example, the pressurized gas can be supplied to the bearing surface only from the supply groove to which the pressurized gas is to be supplied among the plurality of supply grooves. Therefore, it is not always necessary to supply pressurized gas from all the air supply grooves. By supplying pressurized gas only from a desired air supply groove, the pressure (static pressure) at which the hydrostatic bearing pad supports the supported body. The flying height of the bearing pad) can be adjusted. In addition, even when the mass of the support supported by the hydrostatic bearing pad changes greatly, whether or not the pressurized gas is supplied to each of the plurality of air supply grooves, and the pressure condition of the pressurized gas, etc. By individually adjusting, the flying height of the hydrostatic bearing pad can be easily optimized according to the change in the mass of the supported body. As a result, it is possible to realize a hydrostatic bearing pad that can stably support a supported body even when the mass of the supported body changes.

  Therefore, in the hydrostatic bearing pad according to the present invention, the pressurized gas supply unit is preferably capable of independently adjusting the pressure supplied to each of the air supply grooves that supply the pressurized gas to the bearing surface. That is, the function which can supply a pressurized gas only from the desired air supply groove | channel among the several air supply groove | channels provided with the pressurized gas supply part in each of the air supply groove | channel mentioned above. In addition, the pressure of the pressurized gas supplied by each air supply groove can be adjusted independently. In this way, since the pressure of the pressurized gas supplied by each of the plurality of air supply grooves can be arbitrarily adjusted, the size of the pressure at which the hydrostatic bearing pad supports the supported body can be freely set. Can be adjusted.

  In addition, since the pressure of the pressurized gas can be adjusted arbitrarily for each air supply groove, the bearing surface of the bearing member of the hydrostatic bearing pad can be used even when the mass of the supported body or the mass balance thereof varies. And it becomes easier to keep the distance between the bearing surface and the surface facing the bearing surface substantially uniform over the entire surface of the bearing surface.

  Moreover, in the hydrostatic bearing pad which concerns on this invention, it is preferable that the bearing surface is divided | segmented by the exhaust groove which collect | recovers the pressurized gas ejected from the bearing surface again. The bearing member and the housing are formed with an exhaust hole extending from the exhaust groove to the inside of the bearing member and the housing and extending to a surface portion of the housing surface other than the portion connected to the bearing member. More preferably. A plurality of the exhaust grooves may be formed on the bearing surface.

  When the exhaust groove on the bearing surface has an annular shape, the exhaust groove divides the bearing surface into a plurality of regions. Here, for example, consider a case where the bearing surface has one annular exhaust groove, and the bearing surface is divided into two regions of an annular central portion and an outer peripheral portion by the exhaust groove. In this case, the pressurized gas that has reached the inside of the bearing member is ejected from the bearing surface through the air supply groove from the pressurized gas supply portion, but the bearing surface is divided into a central portion and an outer peripheral portion by the exhaust groove. ing. For this reason, the area | region of the bearing surface where pressurized gas is ejected can be limited only to either a center part or an outer peripheral part.

  In the hydrostatic bearing pad according to the present invention, the region formed on the bearing surface by dividing the bearing surface by the exhaust groove is preferably arranged symmetrically with respect to a straight line passing through the center of gravity of the area of the bearing surface. . In this way, the pressurized gas can be ejected from the substantially symmetrical position around the straight line on the bearing surface, and the pressurized gas can be ejected from the substantially symmetrical position around the straight line via the exhaust groove. It can be recovered. For this reason, the attitude | position of a static pressure gas bearing can be stabilized more with respect to the surface which a bearing member opposes.

  Further, in the hydrostatic bearing pad according to the present invention, the following structure can be considered as a structure for ejecting the pressurized gas supplied from the air supply groove to the bearing member side. For example, the above-described bearing member is made of a porous material, and pressurized gas supplied from a plurality of air supply grooves to the bearing member is ejected from the bearing surface through gaps in the porous material forming the bearing member. It is good also as a structure to do. Basically, the pressurized gas supplied from the air supply groove to the bearing member side reaches the bearing surface through the gap of the porous material constituting the bearing member. And the said pressurized gas is ejected from the clearance gap between the porous materials which exist in a bearing surface. At that time, a gap of the porous material existing in the vicinity of the air supply groove to which the pressurized gas is supplied is selected to reach the bearing surface. For this reason, the pressurized gas is selectively ejected from only the region of the bearing surface that substantially coincides with the region facing the supply groove for supplying the pressurized gas. As described above, the pressurized gas can be ejected from only the desired region of the bearing surface by supplying the pressurized gas only from the desired air supply groove.

  In the hydrostatic bearing pad according to the present invention described above, the plurality of air supply grooves are preferably arranged symmetrically with respect to a straight line passing through the center of gravity of the area of the bearing surface. In this case, “symmetry” is a line symmetry with respect to a straight line passing through the area center of gravity and arranged in a direction along the main surface of the bearing surface or a point symmetry with respect to a point on the straight line. A case where the line is symmetrical with respect to a straight line arranged in a direction intersecting with the main surface of the concave part or a point with respect to a point on the straight line is included. Further, in the case of complete line symmetry or point symmetry, and in the case of substantially line symmetry or point symmetry (for example, the center line when the position of the center line of the air supply groove is complete line symmetry or point symmetry) In which the amount of deviation is within 10% of the diameter of a circle circumscribing the shape of the bearing surface).

  As described above, the pressurized gas supplied from the air supply groove selects a gap in the porous material existing in the vicinity of the air supply groove, and reaches the bearing surface through the gap. For this reason, it ejects selectively only from the area | region which substantially corresponds to the area | region which opposes the air supply groove | channel which supplies pressurized gas among bearing surfaces. Therefore, if the plurality of air supply grooves are arranged symmetrically with respect to a straight line passing through the center of gravity of the bearing surface of the bearing member, the pressurized gas supplied from the air supply groove to the bearing member is It is ejected from the bearing surface in a distribution state that is substantially symmetrical with respect to the center of gravity of the area. As described above, the bearing surface of the bearing member of the hydrostatic bearing pad is held so as to keep the distance between the bearing surface and the facing surface substantially constant with respect to the facing surface. As a result, the hydrostatic bearing pad stably supports the supported body. That is, the hydrostatic bearing pad can maintain a stable flying height with respect to the surface facing the above-described bearing surface.

  Further, as another aspect of the hydrostatic bearing pad according to the present invention, the bearing member is formed with air supply holes extending from the air supply groove to the bearing surface, and the plurality of air supply grooves are formed through the air supply holes. The pressurized gas supplied to the bearing member may be ejected from the bearing surface. Here, it is preferable that the air supply holes through which the supplied pressurized gas is ejected are configured to be determined in one way for each air supply groove. In this case, it is preferable that a plurality of air supply holes are formed, and the plurality of air supply holes on the bearing surface are arranged at positions symmetrical with respect to a straight line passing through the center of gravity of the area of the bearing surface. In this way, like the hydrostatic bearing pad in which pressurized gas is ejected from the bearing surface through the gap of the porous material in the bearing member described above, the bearing surface is symmetric with respect to the center of gravity of the area of the bearing surface. Can be ejected. Further, in this case, since the pressurized gas is ejected from the air supply hole, the arrangement of the air supply groove is not related to the pressure distribution of the pressurized gas ejected from the bearing surface. For this reason, the plurality of air supply grooves are not necessarily arranged symmetrically with respect to a straight line passing through the center of gravity of the bearing surface of the bearing member.

  In the hydrostatic bearing pad according to the present invention, the case where the pressurized gas is ejected through the gap of the porous material of the bearing member described above and the case where the pressurized gas is ejected through the plurality of supply holes. In any case, the pressurized gas is ejected from a position symmetrical with respect to the straight line on the bearing surface. Therefore, it is possible to stabilize the position of the bearing surface of the bearing member of the hydrostatic bearing pad with respect to the surface facing the bearing surface (reducing the possibility that the gap between the bearing surface and the surface is locally narrowed) it can). As a result, the hydrostatic bearing pad can stably support the supported body.

  Here, among the plurality of air supply holes described above, one air supply hole that continues to one air supply groove of the plurality of air supply grooves and another air supply groove of the plurality of air supply grooves. The area on the bearing surface with other continuous air supply holes may be changed by ± 10% or more. In this way, if the area of the bearing surface between one air supply hole connected to one air supply groove and another air supply hole connected to the other air supply groove is changed, for example, one air supply groove from the one air supply groove Even if the pressure of the pressurized gas supplied to the air holes is the same as the pressure of the pressurized gas supplied from the other air supply grooves to the other air supply holes, the area of the air supply holes on the bearing surface is different. The pressure of the pressurized gas ejected from one air supply hole and the pressure of the pressurized gas ejected from the other air supply hole can be made different. Therefore, even when the above-described method is used, the degree of freedom in adjusting the magnitude of the pressure with which the pressurized gas supports the supported body can be increased.

  As described above, the linear guide device or the rotary guide device including the hydrostatic bearing pad having any one of the above-described aspects is the mass of the supported body or the supported body supported by the hydrostatic bearing pad. Even when the stress applied to the body changes, the pressurized gas ejected from the bearing surface can be locally controlled, so there is no need to uniformly increase the pressure of the pressurized gas ejected from the entire bearing surface. Therefore, the occurrence of self-excited vibration as in the conventional case can be suppressed.

  Further, by controlling the pressurized gas supply member, the pressure of the pressurized gas ejected from the bearing surface of the bearing member can be locally changed within the bearing surface. The bearing surface can maintain a stable posture with respect to the opposing surface. Therefore, the hydrostatic bearing pad can stably support the supported body.

  According to the present invention, the hydrostatic bearing pad that supports stably regardless of the mass of the supported body by controlling the pressure of the pressurized gas for each supply groove according to the change in the mass of the supported body to be supported. Can be provided. In addition, a linear motion guide device and a rotation guide device using the hydrostatic bearing pad can be provided together.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In each embodiment, portions having the same function are denoted by the same reference numerals, and the description thereof will not be repeated unless particularly necessary.

(Embodiment 1)
1 is a schematic cross-sectional view showing a configuration of a hydrostatic bearing pad according to one aspect of Embodiment 1 of the present invention. FIG. 2 is a schematic cross-sectional view taken along line II-II in FIG. FIG. 3 is a schematic view showing the configuration of the main surface of the bearing surface of FIG. The first embodiment will be described below with reference to the above drawings.

  A hydrostatic bearing pad 110 according to Embodiment 1 of the present invention shown in FIG. 1 is a hydrostatic bearing pad that supports a supported body using a pressurized gas. The hydrostatic bearing pad 110 is mainly composed of a bearing member 20 and a housing 10. The bearing member 20 has a bearing surface 21 as a main surface facing one side, that is, the outside of the hydrostatic bearing pad 110. Here, the main surface refers to the surface having the largest area among the surfaces. Further, the housing 10 has a recess 11 in the lower part in FIG. 1 for accommodating the bearing member 20 so as to fit into the housing 10. In the hydrostatic bearing pad 110, a recess 11 is formed in the housing 10 in order to improve the connection between the bearing member 20 and the housing 10. However, the recess 10 is not necessarily required in the housing 10. Specifically, for example, the surface on which the housing 10 is connected to the bearing member 20 is a flat surface that does not include the recess 11, and may be configured to be fixedly connected to the main surface of the bearing member 20 with an adhesive on the flat surface.

  Since the hydrostatic bearing pad 110 is a member for supporting a supported body, for example, the posture of the hydrostatic bearing pad 110 is maintained in a balanced manner with respect to the surface facing the bearing surface 21 of the hydrostatic bearing pad 110 (the facing surface and the bearing surface). It is preferable that the distance to the bearing 21 is substantially constant over the entire bearing surface 21). Note that, as described above, “symmetry” in this case is a line symmetry with respect to a straight line passing through the center of area and arranged in a direction along the main surface of the recess 11 or a point symmetry with respect to the straight point. In addition, a case where the line is symmetrical with respect to a straight line passing through the area center of gravity and arranged in a direction intersecting the main surface of the concave portion 11 or point-symmetric with respect to the straight point is included. In addition, the case of complete line symmetry or point symmetry and the case of substantially line symmetry or point symmetry are also included.

  The portion where the housing 10 contacts the bearing member 20, that is, the peripheral wall of the recess 11 of the housing 10, and the main surface (bottom wall) of the recess 11 excluding the first air supply groove 51, the second air supply groove 52 and the exhaust groove 31. ) Is fixed by, for example, adhering to the peripheral wall or one main surface of the bearing member 20 with an adhesive. However, any means other than the adhesive may be used as long as the housing 10 and the bearing member 20 can be fixed.

  A plurality of independent air supply grooves for supplying pressurized gas to the bearing surface 21 are formed on the main surface of the recess 11 which is a connection portion with the bearing member 20 of the housing 10. In the hydrostatic bearing pad 110 disclosed in FIGS. 1 to 3, the two air supply grooves are formed as the first air supply groove 51 and the second air supply groove 52. It is good also as a structure which formed the above air supply groove | channels. Further, in the hydrostatic bearing pad 110, an air supply groove is formed in the housing 10, but the same air supply groove is formed on the main surface of the bearing member 20, for example, a connection portion with the housing 10. Also good. Further, a similar air supply groove may be formed in both the bearing member 20 and the housing 10. The first air supply groove 51 and the second air supply groove 52 are independent from each other and are discontinuous with each other. As shown in FIGS. 1 and 2, the pressurized gas to be supplied to the bearing surface 21 is supplied from the first air supply pipe 41 as the pressurized gas supply section for the first air supply groove 51 and second. The air supply grooves 52 are supplied independently from each other from a second air supply pipe 42 as a pressurized gas supply unit.

  In the cross-sectional view of FIG. 1, both the first air supply pipe 41 and the second air supply pipe 42 are shown. However, this is for facilitating the configuration of the cross-sectional view of the hydrostatic bearing pad 110. In practice, the direction in which each air supply pipe extends in the direction along the bearing surface 21, for example, is shown in FIG. As shown in the figure, it does not have to be aligned on a straight line (the angle formed by the extending direction of the first air supply pipe 41 and the extending direction of the second air supply pipe 42 when viewed from the center of the bearing surface 21 is 180 °. Other angles).

  A pressurized gas supplied from a pressurized gas supply source such as a compressor (not shown) in FIG. 1 is supplied from the first supply pipe 41 to the first supply groove 51 via the air tube 73 and the joint 71. In order to use a part of the bearing member 20 as a static pressure for supporting the supported body, a part thereof is ejected from the bearing surface 21 to the outside. Here, in order to control the pressure of the fluid (gas) supplied from the pressurized gas supply source, the air tube 73 is connected to a valve or a pressure reducing valve not shown in FIG. Similarly, pressurized gas supplied from a pressurized gas supply source such as a compressor (not shown) in FIG. 1 is passed from the second supply pipe 42 to the second supply groove 52 via the air tube 74 and the joint 72. A part thereof is ejected from the bearing surface 21 to be used as a static pressure for supporting the supported body. Similarly to the first air supply pipe 41, the air tube 74 is connected to a valve or a pressure reducing valve not shown in FIG.

  Since the first air supply groove 51 and the second air supply groove 52 are discontinuous with each other, the pressurized gas supplied from the first air supply pipe 41 to the first air supply groove 51, The pressurized gas supplied from the second air supply pipe 42 to the second air supply groove 52 can be controlled independently. For example, the valve (not shown in FIG. 1) connected to the air tube 73 is opened, and the valve (not shown in FIG. 1) connected to the air tube 74 is closed. In this way, the pressurized gas is supplied to the first supply groove 51 and the pressurized gas is not supplied to the second supply groove 52. Therefore, when pressurized gas is ejected from the bearing surface 21, a part of the plurality of air supply grooves formed on the main surface of the recess 11 of the housing 10 can be freely selected, and only from the selected air supply groove. The pressurized gas can be supplied to the bearing surface 21. Therefore, it is not always necessary to supply the pressurized gas to the bearing surface 21 from both the first air supply groove 51 and the second air supply groove 52, and the desired air supply groove, for example, the first air supply groove is used. By supplying pressurized gas from only 51 to the bearing surface 21, the pressure with which the pressurized gas supports the supported body can be adjusted. Further, when the mass of the support supported by the hydrostatic bearing pad 110 changes greatly, the first air supply groove 51 and the second air supply groove 52, which are the plurality of air supply grooves, are added. By individually adjusting the presence or absence of the supply of the pressurized gas, the flying height of the hydrostatic bearing pad 110 can be easily optimized according to the change in the mass of the supported body. As a result, it is possible to realize the hydrostatic bearing pad 110 that can stably support the supported body even when the mass of the supported body changes.

  Further, if a pressure reducing valve (not shown in FIG. 1) is connected to the air tube 73 and the air tube 74, a first supply for supplying pressurized gas to the bearing surface 21 for use as a static pressure for supporting the supported body. The pressure of the pressurized gas supplied to each of the air groove 51 and the second air supply groove 52 can be adjusted independently. For example, the pressure reducing valve connected to the air tube 73 is fully opened, and the pressure reducing valve connected to the air tube 74 is half opened. By such a procedure, the pressure of the pressurized gas supplied to each of the first air supply groove 51 and the second air supply groove 52 can be changed. In this way, since the pressure of the pressurized gas supplied from each of the plurality of air supply grooves can be arbitrarily adjusted, the magnitude of the pressure at which the pressurized gas supports the supported body can be freely determined. Can be adjusted. Therefore, the bearing surface 21 of the bearing member 20 of the hydrostatic bearing pad 110 can maintain the arrangement in the direction along the opposing surface and the posture with respect to the surface in a balanced manner. Further, for example, the flying height of the hydrostatic bearing pad 110 with respect to the opposing surface of the bearing surface 21 can be arbitrarily adjusted.

  In the hydrostatic bearing pad 110 according to Embodiment 1 of the present invention, the bearing member 20 is preferably formed of a porous material such as a carbon sintered body. Alternatively, it may be formed of a material that can be a porous material, such as a ceramic sintered body. The pressurized gas supplied to the first supply groove 51 and the second supply groove 52 by the first supply pipe 41 and the second supply pipe 42 is the first supply groove 51 and the second supply pipe 52. By the air groove 52, the bearing member 20 reaches a region near the first air supply groove 51 or the second air supply groove 52 that supplies pressurized gas. Here, if the bearing member 20 is formed of a porous material, only the region in the vicinity of the region to which the pressurized gas is supplied functions as the porous bearing. More specifically, for example, when pressurized gas is supplied only to the first air supply groove 51 by adjusting a valve, the bearing member 20 exists in a region near the first air supply groove 51. Is supported only from a region of the bearing surface 21 in the vicinity of the first air supply groove 51, for example, a region of the bearing surface 21 that faces the first air supply groove 51. Pressurized gas for use as static pressure to support the body is ejected.

  The porous material constituting the bearing member 20 is formed by combining a large number of minute (eg, granular) sintered bodies. Therefore, the porous material has many gaps through which gas can pass. However, as described above, for example, even if pressurized gas is supplied to the bearing member 20 that exists in the region near the first air supply groove 51, the region of the bearing surface 21 that faces the first air supply groove 51. Most of the pressurized gas is ejected from only. For this reason, the pressurized gas for utilizing as a static pressure which supports a to-be-supported body is not ejected from the whole area | region of the bearing surface 21. FIG. Therefore, as described above, a part of the plurality of air supply grooves can be freely selected, and the pressurized gas is supplied to the bearing member 20 only from the selected air supply grooves, so that the porous bearing in the bearing member 20 is provided. A site that functions as can be selected. As a result, it is possible to freely select a region of the bearing surface 21 from which the pressurized gas is ejected.

  Further, by adjusting the supply pressure of the pressurized gas supplied using the above-described pressure reducing valve or a regulator (not shown in FIG. 1), it is ejected from a selected region of the bearing surface 21 of the hydrostatic bearing pad 110. The supply pressure of the pressurized gas can be freely adjusted. Therefore, the bearing surface 21 of the bearing member 20 of the hydrostatic bearing pad 110 can be kept at an appropriate distance from the opposing surface. Further, the flying height of the hydrostatic bearing pad 110 with respect to the opposing surface of the bearing surface 21 can be arbitrarily adjusted.

  Further, a porous bearing formed of a porous material like the bearing member 20, for example, applies an adhesive or the like to the bearing surface 21 or forms a region inside the bearing member 20 or a region near the bearing surface 21. If the porous material is changed, the flow resistance when the pressurized gas flows through the bearing member 20 can be adjusted, and as a result, the bearing characteristics can be changed. Therefore, the bearing characteristics in the region of the bearing member 20 in the vicinity thereof may be changed for each air supply groove constituting the hydrostatic bearing pad 110.

  In addition, it is preferable that the 1st air supply groove | channel 51 and the 2nd air supply groove | channel 52 in FIGS. 1-3 are arrange | positioned symmetrically regarding the straight line which passes along the area gravity center of the main surface of the recessed part 11. FIG. Here, the center of gravity of the area means the center point of the main surface that becomes the bearing surface 21 of the bearing member 20. It is preferable that the first air supply groove 51 and the second air supply groove 52 are arranged so as to be substantially line symmetric with respect to a straight line passing through the area center of gravity or substantially point symmetric with respect to a point on the straight line. As described above, if the first air supply groove 51 and the second air supply groove 52 are arranged symmetrically with respect to a straight line passing through the center of gravity of the area of the bearing surface 21, the first air supply groove 51 and the second air supply groove 52 are arranged. The pressurized gas ejected from the bearing surface 21 through the gap of the porous material constituting the bearing member 20 from the air groove 52 has a pressure distribution that is substantially symmetrical with respect to a straight line passing through the center of gravity of the area of the bearing surface 21. Erupted. As described above, for the pressurized gas supplied from the first air supply groove 51, for example, a gap in the porous material existing in the vicinity of the first air supply groove 51 is selected, and the bearing surface 21 Of these, the gas is selectively ejected only from a region substantially coincident with a region facing the first air supply groove 51 for supplying the pressurized gas. For this reason, if the first air supply groove 51 is arranged symmetrically with respect to a straight line passing through the area centroid of the bearing surface 21, the distribution of the pressurized gas ejected from the bearing surface 21 is the area centroid of the bearing surface 21. The arrangement is almost symmetrical with respect to the straight line passing through. Therefore, the bearing surface 21 of the bearing member 20 of the hydrostatic bearing pad 110 can maintain a good posture with respect to the opposing surface (the distance between the bearing surface 21 and the opposing surface can be kept substantially constant). Become. Further, for example, the flying height of the hydrostatic bearing pad 110 with respect to the opposing surface of the bearing surface 21 can be arbitrarily adjusted.

  Here, as shown in the cross-sectional view of FIG. 2, in the hydrostatic bearing pad 110, the main surface of the concave portion 11 of the housing 10 has a first air supply groove 51 communicating with the first air supply pipe 41, A second air supply groove 52 communicating with the second air supply pipe 42 is formed concentrically. A first air supply pipe 41 is connected to the first air supply groove 51, and a second air supply pipe 42 is connected to the second air supply groove 52. In this way, for example, when the center of the concentric circle forming each air supply groove substantially coincides with the area center of gravity of the main surface of the recess 11, each of the air supply grooves 51, 52 is set to have the area center of gravity of the main surface of the recess 11. It can arrange | position so that it may become symmetrical with respect to the straight line which passes. As described above, this is preferable for maintaining the balance of the bearing member 20 of the hydrostatic bearing pad 110.

  However, the shape in the direction along the main surface of the hydrostatic bearing pad 110 in Embodiment 1 of the present invention does not necessarily have to be circular as shown in the cross-sectional view of FIG. FIG. 4 is a schematic cross-sectional view corresponding to FIG. 2 of a hydrostatic bearing pad having a quadrangular shape in a direction along the main surface. The aspect in the cross-sectional view of FIG. 4 is different from the cross-sectional view of FIG. That is, it has the same mode as the cross-sectional view of FIG. 2 except that it is not a circle but a quadrangle (square). As shown in FIG. 4, the shape in the direction along the main surface of the hydrostatic bearing pad 110 in Embodiment 1 of the present invention may be a square shape (square shape). Also in this case, the same operation as the hydrostatic bearing pad 110 having the cross section shown in FIG. In addition, the shape in the direction along the main surface of the hydrostatic bearing pad 110 can be selected from various shapes such as a hexagonal shape, a triangular shape, and a fan shape.

  Further, as shown in FIG. 4, the first air supply groove 51 and the second air supply groove 52 are not necessarily circular as in the case of the hydrostatic bearing pad 110. In the direction along the main surface, the shape may be selected from various shapes such as a triangular shape, a quadrangular shape, a pentagonal shape, a polygonal shape such as a hexagonal shape, or a fan shape. However, as shown in FIG. 2 or FIG. 4, the first supply groove 51 and the second supply groove 52, which are a plurality of supply grooves, are also used as bearing members for the above-described various shapes of the supply grooves. It is preferable that the 20 bearing surfaces 21 are arranged so as to be concentrically symmetrical with respect to a straight line passing through the center of gravity of the area of the bearing surface 21. If it does in this way, pressurized gas can be ejected from the substantially symmetrical position in the bearing surface 21 centering on the straight line which passes through the said area gravity center. For this reason, the attitude | position of a static pressure gas bearing can be stabilized more with respect to the surface which a bearing member opposes.

  For example, as shown in FIG. 1, an exhaust groove 33 is formed on the bearing surface 21 of the bearing member 20 to recover again the pressurized gas ejected from the bearing surface 21. The interior of the bearing member 20 and the inside of the housing 10 are extended from the exhaust groove 33 to the exhaust hole 32 extending through the inside of the bearing member 20 and the interior of the housing 10, and the surface of the housing 10 other than the recess 11 (for example, In FIG. 1, an exhaust hole 30 extending to the main surface of the housing 10 opposite to the main surface facing the bearing member 20 is formed. The exhaust hole 30 and the exhaust hole 32 are connected to each other via an exhaust groove 31 formed in the recess 11 on the main surface of the recess 11 that is a boundary between the bearing member 20 and the housing 10. Two or more (a plurality of) exhaust grooves 33 may be formed on the bearing surface 21. Further, when a plurality of exhaust grooves 33 are formed, the exhaust holes 32 and 30 as described above may be formed for each of the exhaust grooves 33, or a common exhaust hole 32 for the plurality of exhaust grooves 33. 30 may be formed.

  A part of the pressurized gas supplied to the inside of the bearing member 20 is ejected from the bearing surface 21 for use as a static pressure through the gap of the porous material constituting the bearing member 20 as described above. The In order to exhaust the pressurized gas ejected from the bearing surface 21 in this way from the space between the surface facing the bearing surface 21 to the outside of the hydrostatic bearing pad 110, the exhaust holes 30 and 32 and the exhaust groove 31. Is formed. Specifically, a part of the pressurized gas supplied to the space is introduced into the exhaust hole 32 through the exhaust groove 33 formed in the bearing surface 21 of the bearing member 20. The pressurized gas introduced into the exhaust hole 32 is an outlet of the exhaust hole 30 through the exhaust groove 31 and the exhaust hole 30 (a surface portion of the surface of the housing 10 other than the portion connected to the bearing member 20). The air is exhausted from the uppermost part of the exhaust hole 30 in FIG.

  As shown in FIG. 3, the exhaust groove 33 described above divides the bearing surface 21 into two regions of a central portion 22 and an outer peripheral portion 23. Here, for example, the pressurized gas supplied from the first air supply groove 51 passes through the gap of the porous material existing in the vicinity of the first air supply groove 51, and the first of the bearing surfaces 21. It is ejected from the vicinity of the region facing the air supply groove 51. At this time, for example, if the region where the first air supply groove 51 faces the bearing surface 21 is the central portion 22 of the bearing surface 21, the first air supply groove 51 passes through the gap of the porous material. The pressurized gas that has reached the bearing surface 21 is ejected from the central portion 22 but is not ejected from the outer peripheral portion 23. This is because the exhaust groove 33 that divides the bearing surface 21 into two regions of the central portion 22 and the outer peripheral portion 23 prevents the pressurized gas in the central portion 22 from being ejected from the outer peripheral portion 23. Therefore, in the bearing surface 21, the area | region which ejects pressurized gas can be divided. As a result, the pressurized gas ejected from the bearing surface 21 can be controlled more precisely.

  As shown in the schematic view of the bearing surface 21 in FIGS. 1 and 3, the exhaust hole 32 is formed, for example, in the bearing member 20 in the direction along the main surface of the bearing member 20. It is preferable to form a concentric circle similar to the second air supply groove 52. However, similarly to the first air supply groove 51 and the second air supply groove 52, the exhaust groove 31 and the exhaust groove 33 do not necessarily need to be circular as shown in FIG. In the direction along the main surface, a polygonal shape such as a triangular shape, a quadrangular shape, a pentagonal shape, a hexagonal shape, or a sector shape may be selected.

  As described above, the exhaust groove 33 formed in the bearing surface 21 is formed by dividing the bearing surface 21, so that the two regions of the center portion 22 and the outer peripheral portion 23 have the area center of gravity of the bearing surface 21. It is preferable that they are arranged symmetrically with respect to the straight line passing through.

  In this way, the pressurized gas can be ejected from the substantially symmetric position around the straight line on the bearing surface 21, and the pressurized gas is passed through the exhaust groove 33 from the substantially symmetric position around the straight line. The gas can be recovered. For this reason, the attitude | position of the hydrostatic bearing pad 110 can be stabilized more with respect to the surface which the bearing member 20 opposes.

  In the cross-sectional view of FIG. 1, the exhaust hole 30 extends from the exhaust groove 31 on the main surface of the recess 11 of the housing 10 toward the main surface of the housing 10 opposite to the surface facing the bearing member 20. It extends perpendicular to the ten major surfaces. However, the exhaust hole 30 may have a structure extending obliquely with respect to the main surface of the housing 10 in the cross-sectional view of FIG. For example, the outlet of the exhaust hole 30 may be present on the left and right side surfaces of the housing 10 in the cross-sectional view of FIG. That is, it can be set as the structure where an exit exists in arbitrary surface parts other than the part connected to the bearing member 20 among the surfaces of the housing 10. However, in order to keep the balance and flying height of the hydrostatic bearing pad 110 stable and substantially constant when exhausting from the outlet of the exhaust hole 30, the outlet of the exhaust hole 30 has, for example, the center of gravity of the area of the bearing surface 21. It is preferable to form it so as to be symmetric with respect to a straight line passing therethrough.

  FIG. 5 is a schematic cross-sectional view showing a configuration of a hydrostatic bearing pad according to another aspect of the first embodiment of the present invention. 6 is a schematic cross-sectional view taken along line VI-VI in FIG. In the following description, the direction along the main surface of the hydrostatic bearing pad 110 and the air supply and exhaust grooves are circular, but other shapes can be selected as described above.

  As shown in FIGS. 1 and 2 described above, in the case of the hydrostatic bearing pad 110, for example, the first air supply groove 51 has two concentric air supply grooves having different diameters (concentric with the concentric groove A in FIG. 2). The groove B) is connected by a bypass 49 to form one first air supply groove 51. Therefore, for example, when pressurized gas is supplied to the concentric groove B from the first air supply pipe 41 existing in the concentric groove B in FIG. 2, the pressurized gas reaches the concentric groove A via the bypass 49 and is connected thereto. The first air supply groove 51 reaches the concentric groove A and the concentric groove B and all regions of the bypass 49. Similarly, for example, when pressurized gas is supplied to the concentric groove D from the second air supply pipe 42 existing in the concentric groove D in FIG. 2, the pressurized gas reaches the concentric groove C via the bypass 48 and is connected. The concentric groove C and the concentric groove D of the second air supply groove 52 and the entire region of the bypass 48 are reached.

  However, in the case of the hydrostatic bearing pad 120 shown in FIGS. 5 and 6, the pressurized gas is supplied from the first supply groove 51 and the second supply pipe 42 to which the pressurized gas is supplied from the first supply pipe 41. In addition to the supplied second supply groove 52, the pressurized gas is supplied from the third supply groove 53 to which the pressurized gas is supplied from the third supply pipe 43 and the fourth supply pipe 44. A fourth air supply groove 54 is disposed.

  In the case of the hydrostatic bearing pad 110 shown in FIGS. 1 to 3, two concentric circular grooves A, B, C, and D constituting the air supply groove are connected via the bypasses 48 and 49, respectively. One set (one) of the air supply grooves (the first air supply groove 51 and the second air supply groove 52) is formed by the book. However, the hydrostatic bearing pad 120 shown in FIGS. 5 and 6 has four concentric grooves each having the same concentric diameter as the hydrostatic bearing pad 110. However, the concentric grooves (air supply grooves 51 to 51) are formed. 54) are not connected by a bypass, and independently form a first air supply groove 51, a second air supply groove 52, a third air supply groove 53, and a fourth air supply groove 54. In the case of the hydrostatic bearing pad 110, the supply of the pressurized gas to the bearing surface 21 is controlled using substantially two air supply pipes and the air supply groove. However, in the case of the hydrostatic bearing pad 120, the hydrostatic bearing is used. Although the air supply groove having a configuration similar to that of the pad 110 is provided, the supply of pressurized gas to the bearing surface 21 can be controlled using substantially four air supply pipes and air supply grooves. For this reason, the hydrostatic bearing pad 120 can maintain the attitude of the hydrostatic bearing pad 120 with respect to the surface of the bearing member 20 that faces the bearing surface 21 in a balanced manner more precisely than the hydrostatic bearing pad 110. Further, for example, the flying height of the hydrostatic bearing pad 120 with respect to the opposing surface of the bearing surface 21 can be adjusted more strictly.

  In the cross-sectional view of FIG. 5 as well, all four air supply pipes are shown in the same manner as in the cross-sectional view of FIG. 1, but this is to facilitate the configuration of the cross-sectional view of the hydrostatic bearing pad 120. Actually, for each air supply pipe, for example, the direction (angle) extending in the direction along the bearing surface 21 may be different (the direction is 1 as shown in the sectional view of FIG. 1). Do not have to be aligned on a straight line). In FIG. 5, a part of the third air supply pipe 43 and the fourth air supply pipe 44 is not shown for easy viewing of the drawing.

  The hydrostatic bearing pad 120 differs from the hydrostatic bearing pad 110 only in the points described above. That is, regarding the hydrostatic bearing pad 120, the configurations, conditions, effects, and the like not described above all follow the hydrostatic bearing pad 110.

(Embodiment 2)
FIG. 7 is a schematic cross-sectional view showing a configuration of a hydrostatic bearing pad according to one aspect of the second embodiment of the present invention. FIG. 8 is a schematic view showing the configuration of the main surface of the bearing surface of FIG. FIG. 9 is a schematic cross-sectional view taken along line IX-IX in FIG. The second embodiment will be described below with reference to the above drawings.

  The hydrostatic bearing pad 130 according to the second embodiment of the present invention basically includes the same aspects as the hydrostatic bearing pad 110 and the hydrostatic bearing pad 120 according to the first embodiment of the present invention. However, as shown in FIG. 7, in the hydrostatic bearing pad 130, one main surface of the bearing member 20 facing the first air supply groove 51 and the second air supply groove 52 (see FIG. 7, the air supply hole extending from the upper main surface of the bearing member 20 to the bearing surface 21 is formed. The first air supply groove 51 shown in FIG. 7 is arranged to be continuous with the first air supply hole 61, and the second air supply groove 52 is connected to the second air supply hole 62.

  The pressurized gas supplied to the first air supply groove 51 and the second air supply groove 52 by the first air supply pipe 41 and the second air supply pipe 42 is the first air supply groove 51 and the second air supply groove 52, respectively. The air is introduced into the first air supply hole 61 and the second air supply hole 62 extending from the air supply groove 52 to the bearing surface 21. As shown in FIGS. 7 and 8, the pressurized gas flows through the first air supply hole 61 and the second air supply hole 62 that extend to the bearing surface 21. And the pressurized gas for utilizing as a static pressure which supports a to-be-supported body is ejected from the exit of the 1st air supply hole 61 and the 2nd air supply hole 62 in the bearing surface 21 shown in FIG. The pressurized gas supplied from the first air supply groove 51 is ejected from the first air supply hole 61, and the pressurized gas supplied from the second air supply groove 52 is ejected from the second air supply hole 62 on a one-to-one basis. It becomes the composition which is done. As shown in FIG. 8, the first air supply hole 61 and the second air supply hole 62 are arranged concentrically (circumferentially) on the bearing surface 21.

  In the hydrostatic bearing pad 110 and the hydrostatic bearing pad 120 according to the first embodiment of the present invention, the pressurized gas supplied to the inside of the bearing member 20 is supported through a porous gap forming the bearing member 20. It is ejected from the surface 21. That is, the hydrostatic bearing pads 110 and 120 are porous throttle type hydrostatic bearing pads. On the other hand, in the hydrostatic bearing pad 130 according to Embodiment 2 of the present invention, the pressurized gas supplied into the bearing member 20 is the first air supply hole 61 formed in the bearing member 20. Then, it is ejected from the bearing surface 21 through the second air supply hole 62. That is, the hydrostatic bearing pad 130 is a self-contained type hydrostatic bearing pad. Thus, instead of the porous gap of the bearing member 20, it is also possible to eject pressurized gas from the bearing surface 21 through the air supply holes formed in the bearing member 20. In this way, since only the pressurized gas that has reached the bearing surface 21 is ejected through the air supply holes formed inside the bearing member 20, depending on how the air supply holes are formed (the size and shape of the air supply holes, The pressure at which the pressurized gas supports the supported body can be adjusted in (Arrangement).

  In addition, about the bearing member 20 which comprises the static pressure bearing pad 130, since the pressurized gas is supplied using the 1st air supply hole 61 and the 2nd air supply hole 62, the material which comprises the bearing member 20 is not necessarily porous. It need not be a quality material. However, if a porous material similar to the hydrostatic bearing pads 110 and 120 is used as the material constituting the bearing member 20, the porous material present in the region other than the first air supply holes 61 and the second air supply holes 62. It is preferable to fill and seal the gap and the porous gap existing on the bearing surface 21 using a filler such as a resin. In this way, the pressurized gas is ejected from any location on the bearing surface 21 other than the first air supply hole 61 and the second air supply hole 62, making it difficult to control the above-described static pressure and flying height. Can be prevented from occurring.

  As shown in FIG. 7 and FIG. 8, the plurality of first air supply holes 61 and second air supply holes 62 that are formed are symmetrically arranged on the bearing surface 21 with respect to a straight line that passes through the center of gravity of the area of the bearing surface 21. Is preferred. In this way, the pressurized gas ejected from the air supply holes 61 and 62 is ejected from a position symmetrical to the straight line on the bearing surface 21. Therefore, since the pressure distribution of the jetted pressurized gas can be made symmetric with respect to a straight line passing through the center of gravity of the area of the bearing surface 21, the bearing surface 21 of the bearing member 20 of the hydrostatic bearing pad 130 is The position with respect to the opposing surface can be stabilized (the possibility that the gap between the bearing surface 21 and the surface is locally narrowed can be reduced). As a result, the hydrostatic bearing pad 130 can stably support the supported body. Further, for example, it becomes easy to keep the flying height of the hydrostatic bearing pad 130 with respect to the opposing surface of the bearing surface 21 uniform over the entire bearing surface 21.

  However, in the case of the hydrostatic bearing pad 130, for example, as in the hydrostatic bearing pad 110 described above, the pressurized gas supplied from the air supply groove to the bearing member passes through the gap between the porous materials constituting the bearing member 20. It is not configured to reach the bearing surface 21. Therefore, the arrangement of the first air supply groove 51 and the second air supply groove 52 is almost independent of the pressurization distribution of the pressurized gas ejected from the bearing surface 21. For this reason, in the hydrostatic bearing pad 130, the first air supply groove 51 and the second air supply groove 52 do not necessarily have to be arranged symmetrically with respect to a straight line passing through the center of gravity of the area of the bearing surface 21.

  Further, in the hydrostatic bearing pad 130, for example, the areas of the plurality of first air supply holes 61 and the second air supply holes 62 on the bearing surface 21 shown in FIG. Here, ± 10% is the percentage value of the difference between the areas of the two types of air supply holes 61 and 62 with reference to the smaller one of the first air supply hole 61 and the second air supply hole 62. Means ± 10.

  For example, when six first air supply holes 61 are formed in the center portion 22 and 12 second air supply holes 62 are formed in the outer peripheral portion 23 on the bearing surface 21 in FIG. The first air supply holes 61 and the second air supply holes 62 in the bearing surface 21 are changed by changing the diameters (diameters of the holes) of the first air supply holes 61 and the 12 second air supply holes 62. The area with the pores 62 is changed. In this way, for example, even if the pressure of the pressurized gas supplied to the first air supply groove 51 and the second air supply groove 52 is the same, the bearing surface 21 via the first air supply hole 61. The pressure of the pressurized gas supplied to the bearing surface 21 and the pressure of the pressurized gas supplied to the bearing surface 21 via the second air supply hole 62 can be changed. Therefore, even if the above-described method is used, the degree of freedom in adjusting the pressure with which the pressurized gas supports the supported body can be increased.

  Of the twelve second air supply holes 62, for example, only the four second air supply holes 62 E, F, G, and H shown in FIG. 8 are changed in area on the bearing surface 21 as described above. May be. In this way, the area of only some of the plurality of air supply holes communicating with the same air supply groove may be changed. However, in this case, it is preferable that the air supply holes selected for changing the area, such as E, F, G, and H described above, be selected so as to be arranged symmetrically with respect to the center of gravity of the area of the bearing surface 21. Therefore, for example, it is possible to change the area of only E and G. However, in any case, it is preferable that the areas of the air supply holes whose areas are changed are all equal. In this way, the bearing surface 21 of the bearing member 20 of the hydrostatic bearing pad 110 can maintain a balanced posture with respect to the opposing surface. Further, for example, the degree of freedom in adjusting the flying height of the hydrostatic bearing pad 110 with respect to the opposing surface of the bearing surface 21 can be increased.

  Moreover, in FIG. 8, the shape of the exit in the bearing surface 21 of the 1st air supply hole 61 and the 2nd air supply hole 62 is circular. However, the shape is not necessarily circular. For example, a polygonal shape such as a triangular shape or a quadrangular shape, or any other arbitrary shape can be adopted.

  Furthermore, for example, a pocket provided with a counterbore hole having a certain depth in the region near the outlet of the bearing surface 21 of the first air supply hole 61 and the second air supply hole 62, or a width around the hole forming the outlet. You may provide the groove | channel which spreads with. By providing these pockets and grooves, the pressure gas in the vicinity of the outlets of the bearing surfaces 21 of the first air supply holes 61 and the second air supply holes 62 is diffused to the portions where the pockets and grooves are formed, thereby the vicinity of the outlets. The pressure distribution can be changed.

  The second embodiment of the present invention differs from the first embodiment of the present invention only in the points described above. That is, for example, configurations, conditions, procedures, effects, and the like not described above with respect to the second embodiment of the present invention are all in accordance with the first embodiment of the present invention. Therefore, in the hydrostatic bearing pad 130, for example, as shown in FIG. 9, the first air supply groove 51 and the second air supply groove 52 are not connected to each other by, for example, the bypass 48 (see FIG. 1) described above. It is the structure formed by the concentric groove | channel of a book. However, for example, with respect to the housing 10 having the first air supply groove 51 in which the two concentric grooves A and the concentric grooves B are connected by the bypass 49 as in the hydrostatic bearing pad 110 of FIG. In addition, a hydrostatic bearing pad having a configuration in which the bearing member 20 having an air supply hole for the self-contained throttle system, such as the hydrostatic bearing pad 130, is disposed. Alternatively, an air supply hole for forming a self-contained throttle system like a hydrostatic bearing pad 130 with respect to a housing 10 having four air supply grooves that are not connected to each other like the hydrostatic bearing pad 120 of FIG. It is good also as a hydrostatic bearing pad of the structure which has arrange | positioned the bearing member 20 provided with.

(Embodiment 3)
FIG. 10 is a schematic cross-sectional view showing a configuration of a hydrostatic bearing pad according to one aspect of the third embodiment of the present invention. 11 is a schematic cross-sectional view taken along line XI-XI in FIG. FIG. 12 is a schematic view showing the configuration of the main surface of the bearing surface of FIG. The third embodiment will be described below with reference to the above drawings.

  The hydrostatic bearing pad 140 according to the third embodiment of the present invention basically has the same aspect as the hydrostatic bearing pad 130 according to the second embodiment of the present invention. It is. However, as shown in FIGS. 10 and 11, in the hydrostatic bearing pad 140, the outer periphery of the concentric circle formed by the outer first air supply groove 51 (the diameter of the concentric circle is large) among the air supply grooves in FIG. 11. And six regions on the inner circumference of the concentric circle formed by the second air supply groove 52 (regions I to T in FIG. 11) are formed so that the grooves protrude like gear teeth. Of the first air supply groove 51 and the second air supply groove 52, the first air supply hole 61 and the second air supply hole that extend from the respective regions I to T described above to the bearing surface 21. 62 is formed. Each air supply hole extended from each area | region of IT of FIG. 11 is connected to each air supply hole of I'-T 'in FIG. The schematic view of the bearing surface 21 in FIG. 12 includes a third air supply formed by the first air supply holes 61, the second air supply holes 62, and the third air supply grooves 53 shown in FIGS. 10 and 11. The pores 63 are described.

  The configuration of the bearing surface 21 of the hydrostatic bearing pad 140 shown in FIG. 12 is the same as the configuration of the bearing surface 21 of the hydrostatic bearing pad 130 shown in FIG. Although the reference numbers of the air supply holes are different, for example, E, F, G, H of the second air supply hole 62 in FIG. 8 are I ′ of the first air supply hole 61 (second air supply hole 62) in FIG. This is the same mode as L ′, O ′, and R ′. However, for each air supply hole in the bearing surface 21 of the hydrostatic bearing pad 130 in the second embodiment of the present invention, for example, all the 12 air supply holes in the outer peripheral portion 23 of the bearing surface 21 in FIG. As the air supply hole 62, the pressurized gas supplied through the second air supply pipe 42 and the second air supply groove 52 is supplied. On the other hand, twelve air supply holes (I ′ to T ′ in FIG. 12) existing in the outer peripheral portion 23 of the bearing surface 21 of the hydrostatic bearing pad 140 in Embodiment 3 of the present invention are I ′, K ', M', O ', Q' and S 'are first air supply holes 61 starting from the regions I, K, M, O, Q and S of the first air supply groove 51 shown in FIG. It is. Further, J ′, L ′, N ′, P ′, R ′, and T ′ are second points starting from J, L, N, P, R, and T of the second air supply groove 52 shown in FIG. This is the air supply hole 62.

  If it does in this way, the number selected as an air supply hole which injects pressurized gas among the self-contained throttle-type air supply holes formed in large numbers on the bearing surface 21 can be controlled easily. For example, in the case of the hydrostatic bearing pad 130, if pressurized gas is supplied from the second air supply pipe 42, the twelve second air supply holes 62 existing on the outer peripheral portion 23 of the bearing surface 21 in FIG. Pressurized gas is ejected. On the other hand, in the case of the hydrostatic bearing pad 140, if the pressurized gas is supplied only from the second air supply pipe 42, among the 12 air supply holes existing in the outer peripheral portion 23 of the bearing surface 21 in FIG. Pressurized gas is ejected from only six (J ′, L ′, N ′, P ′, R ′ and T ′). Further, if pressurized gas is supplied only from the first air supply pipe 41, six of the 12 air supply holes (I ′, K ′, M ′, Pressurized gas is ejected from only O ′, Q ′ and S ′). Therefore, it is possible to more easily control the static pressure, the flying height, and the like by ejecting the pressurized gas.

  Also in the third embodiment of the present invention, as in the second embodiment of the present invention described above, for example, a plurality of first air supply holes 61 and second air supply holes 62 in the bearing surface 21 shown in FIG. The areas may be changed by ± 10% or more. At this time, the air supply holes for changing the area are preferably selected so as to be symmetric with respect to the center of gravity of the area of the bearing surface 21. Moreover, you may provide the pocket and groove | channel for adjusting pressure distribution in the area | region of the exit vicinity in the bearing surface 21 of the said air supply hole.

  The third embodiment of the present invention differs from the first or second embodiment of the present invention only in the points described above. That is, for example, configurations, conditions, procedures, effects, and the like not described above with respect to the third embodiment of the present invention are all in accordance with the first or second embodiment of the present invention.

(Embodiment 4)
FIG. 13: is a schematic sectional drawing which shows the aspect of the linear guide apparatus using the hydrostatic bearing pad which concerns on Embodiment 1-3 of this invention. With reference to FIG. 13, the linear motion guide apparatus provided with the hydrostatic bearing pad of this invention is demonstrated.

  A linear motion guide device 150 shown in FIG. 13 is a part of a semiconductor exposure apparatus that performs photolithography, for example. The movement can be controlled on one main surface of the base 125 (upper side in FIG. 13) using, for example, a motor, an encoder, or a controller not shown in FIG. 13 in a direction along the depth direction of the paper surface in FIG. A guide member 108 serving as a reference for arranging the movable table 100 and the hydrostatic bearing pad at a stable position is provided. The movable table 100 is mounted with a workpiece 135 that is a position control target (for example, a substrate to be exposed in the case of performing photolithography for forming an element on the surface of a semiconductor wafer and the substrate holder). .

  In order to support the movable table 100 while maintaining the stable arrangement of the movable table 100 with respect to the main surface of the guide member 108 even if the mass of the workpiece 135 varies, the hydrostatic bearing pad 110 (in FIG. Bearing pad 110 is shown, but may be, for example, hydrostatic bearing pads 120, 130, 140).

  As shown in FIG. 13, the hydrostatic bearing pad 110 is disposed on each surface of the movable table 100 facing the guide member 108. The main surface (back surface) opposite to the main surface (recess 11 (see FIG. 1)) of the housing 10 (see FIG. 1) of the hydrostatic bearing pad 110 facing the bearing member 20 (see FIG. 1) It is connected to each surface of the movable table 100 via a ball stud 106. In this way, the direction of the main surface of the hydrostatic bearing pad 110 (the direction of the bearing surface) relative to the direction formed by the main surface of the movable table 100 can be made variable. The ball stud 106 is attached to the back surface of the housing 10 of the hydrostatic bearing pad 110, and the mounting position thereof is a straight line that passes through the vicinity of the center of gravity of the bearing surface and is substantially orthogonal to the bearing surface, and the back surface of the housing 10. It is preferable to arrange in the vicinity of the intersecting position. In this way, the hydrostatic bearing pad 110 can be stably attached to the movable table 100, and the hydrostatic bearing pad 110 can be prevented from receiving an unnecessary moment load from the bearing surface 21.

  For example, when the linear motion guide device 150 is operated in this state, the movable table 100 on which the workpiece 135 is mounted moves along the movable direction of the motor coil unit 145 and the motor magnet unit 142 for driving the movable table 100. Move in the depth direction. At this time, the position of the movable table 100 is also confirmed by the sensor 141 as needed, but the hydrostatic bearing pad 110 attached on the main surface of the movable table 100 adjusts the flying height of the opposing guide member 108 with respect to the main surface. Or the bearing surface 21 serves to keep the arrangement of the movable table 100 in a balanced manner so that the bearing surface 21 is in a direction along the main surface of the opposing guide member 108. Here, for example, even if the mass of the workpiece 135 varies, the hydrostatic bearing pad 110 adjusts the static pressure between the bearing surface 21 and the main surface of the guide member 108 (the pressure supplied to the hydrostatic bearing pad 110). By changing the pressure of the pressurized gas or controlling the presence or absence of supply of pressurized gas to the first and second supply grooves 51 and 52 (see FIG. 1), the hydrostatic bearing pad 110 The flying height with respect to the main surface of the opposing guide member 108 can be adjusted. In this way, the hydrostatic bearing pad 110 supports the movable part (the movable table 100 in FIG. 13) or the fixed part, which is a supported body.

(Embodiment 5)
FIG. 14 is a schematic cross-sectional view showing an aspect of a rotation guide device using a hydrostatic bearing pad similar to the hydrostatic bearing pad according to the first to third embodiments of the present invention. With reference to FIG. 14, the rotation guide apparatus provided with the hydrostatic bearing pad according to the present invention will be described.

  FIG. 14 illustrates a configuration of a CT scanner as an example of the rotation guide device 250. The rotation guide device (CT scanner) shown in FIG. 14 includes a non-rotating unit 201 and a rotating shaft 202 as a rotating body. A plurality of hydrostatic bearing pads 203 fixed to the non-rotating portion 201 support the rotating shaft 202. Since the hydrostatic bearing pad 203 is for the rotation guide device 250, for example, the main surface (bearing surface 21) of the bearing member 20 is curved so that the bearing member 20 (see FIG. 1) has a shape along the outer peripheral surface of the rotating shaft 202. It differs from the hydrostatic bearing pad shown in each embodiment of the present invention described above in that it has a shape. However, also in the hydrostatic bearing pad 203, pressurized gas is ejected from the bearing surface 21 (see FIG. 1) of the bearing member 20 on the same principle as the hydrostatic bearing pad shown in each embodiment of the present invention described above. Thus, the outer peripheral surface of the rotating shaft 202 can be supported in a non-contact manner. As shown in FIG. 14, the hydrostatic bearing pads 203 are arranged at five locations on the outer peripheral surface of the rotating shaft 202. As described above, the rotary shaft 202 is supported in a non-contact manner in the axial direction and the radial direction by the pressurized gas ejected from the hydrostatic bearing pad 203 from multiple directions on the outer peripheral surface of the rotary shaft 202. Therefore, quiet high speed operation of the rotating shaft 202 is possible.

  And also about the hydrostatic bearing pad 203, the pressurized gas which ejects from the hydrostatic bearing pad 203 according to the mass of the rotating shaft 202 similarly to the hydrostatic bearing pad shown to each above-mentioned embodiment of this invention. adjust. In this way, it is possible to adjust the flying height with respect to the outer peripheral surface of the rotating shaft 202 and the static pressure between the outer peripheral surface of the rotating shaft 202 and the bearing surface of the hydrostatic bearing pad 203.

  Each embodiment disclosed this time must be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  The present invention is particularly excellent as a technique for supporting stably regardless of the mass of the support by controlling the static pressure according to the change in the mass of the support.

It is a schematic sectional drawing which shows the structure of the hydrostatic bearing pad which concerns on one situation of Embodiment 1 of this invention. It is a schematic sectional drawing in line segment II-II of FIG. It is the schematic which shows the structure of the main surface of the bearing surface of FIG. FIG. 3 is a schematic cross-sectional view corresponding to FIG. 2 of a hydrostatic bearing pad having a quadrangular shape in a direction along the main surface. It is a schematic sectional drawing which shows the structure of the hydrostatic bearing pad which concerns on the other situation of Embodiment 1 of this invention. It is a schematic sectional drawing in line segment VI-VI of FIG. It is a schematic sectional drawing which shows the structure of the hydrostatic bearing pad which concerns on one situation of Embodiment 2 of this invention. It is the schematic which shows the structure of the main surface of the bearing surface of FIG. It is a schematic sectional drawing in line segment IX-IX of FIG. It is a schematic sectional drawing which shows the structure of the hydrostatic bearing pad which concerns on one situation of Embodiment 3 of this invention. It is a schematic sectional drawing in line segment XI-XI of FIG. It is the schematic which shows the structure of the main surface of the bearing surface of FIG. It is a schematic sectional drawing which shows the aspect of the linear motion guide apparatus using the hydrostatic bearing pad which concerns on Embodiment 1-3 of this invention. It is a schematic sectional drawing which shows the aspect of the rotation guide apparatus using the same hydrostatic bearing pad as the hydrostatic bearing pad which concerns on Embodiment 1-3 of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 Housing, 11 Concave part, 20 Bearing member, 21 Bearing surface, 22 Center part, 23 Outer part, 30 Exhaust hole, 31 Exhaust groove, 32 Exhaust hole, 33 Exhaust groove, 41 1st supply pipe, 42 2nd supply Trachea, 43 third supply pipe, 44 fourth supply pipe, 48 bypass, 49 bypass, 51 first supply groove, 52 second supply groove, 53 third supply groove, 54 fourth Air supply groove, 61 1st air supply hole, 62 2nd air supply hole, 63 3rd air supply hole, 71 joint, 72 joint, 73 air tube, 74 air tube, 100 movable table, 106 ball stud, 108 guide member 110 hydrostatic bearing pad, 120 hydrostatic bearing pad, 125 base, 130 hydrostatic bearing pad, 135 workpiece, 140 hydrostatic bearing pad, 141 sensor, 142 motor magnet Part, 145 motor coil part, 150 linear motion guide device, 201 non-rotating part, 202 rotating shaft, 203 hydrostatic bearing pad, 250 rotation guiding device.

Claims (11)

A hydrostatic bearing pad that supports a support using a pressurized gas,
A bearing member having a bearing surface;
A housing for holding the bearing member;
In the connecting portion between the bearing member and the housing, a plurality of independent air supply grooves for supplying the pressurized gas to the bearing surface are formed in at least one of the bearing member and the housing,
A hydrostatic bearing pad provided with a pressurized gas supply unit that supplies the pressurized gas independently to each of a plurality of the air supply grooves.   The hydrostatic bearing pad according to claim 1, wherein the pressurized gas supply unit is capable of independently adjusting a pressure supplied to each of the air supply grooves that supply the pressurized gas to the bearing surface. The bearing surface is divided by an exhaust groove for recovering again the pressurized gas ejected from the bearing surface,
The bearing member and the housing extend from the exhaust groove to the inside of the bearing member and the housing and extend to the surface portion of the surface of the housing other than the portion connected to the bearing member. The hydrostatic bearing pad according to claim 1 or 2, wherein a hole is formed.   The hydrostatic bearing pad according to claim 3, wherein a region formed in the bearing surface by dividing the exhaust groove by the exhaust groove is arranged symmetrically with respect to a straight line passing through the center of gravity of the area of the bearing surface.   The bearing member is made of a porous material, and the pressurized gas supplied from the plurality of air supply grooves to the bearing member through the gaps in the porous material forming the bearing member is used as the bearing surface. The hydrostatic bearing pad according to any one of claims 1 to 4, which is ejected from the hydrostatic bearing pad.   The hydrostatic bearing pad according to claim 5, wherein the plurality of air supply grooves are arranged symmetrically with respect to a straight line passing through the center of gravity of the area of the bearing surface. The bearing member is formed with an air supply hole extending from the air supply groove to the bearing surface,
The static pressure according to any one of claims 1 to 4, wherein the pressurized gas supplied to the bearing member from a plurality of the air supply grooves is ejected from the bearing surface through the air supply hole. Bearing pad. A plurality of the air supply holes are formed,
The hydrostatic bearing pad according to claim 7, wherein the plurality of air supply holes in the bearing surface are arranged at positions symmetrical with respect to a straight line passing through the center of gravity of the area of the bearing surface.   Among the plurality of air supply holes, one air supply hole that continues to one of the plurality of air supply grooves, and another that connects to another air supply groove of the plurality of air supply grooves The hydrostatic bearing pad according to claim 7 or 8, wherein an area of the air bearing hole on the bearing surface is changed by ± 10% or more.   A linear motion guide apparatus comprising the supported body supported by the hydrostatic bearing pad according to claim 1.   A rotation guide device comprising the supported body supported by the hydrostatic bearing pad according to claim 1.

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