JP4483430B2 - Combination structure of hydrostatic gas bearing pad and gap adjusting member, and hydrostatic gas bearing mechanism using the same - Google Patents

Description

  The present invention relates to a static pressure gas bearing pad interposed between a movable body and a fixed body, which should hold the movable body movably with respect to the fixed body, and between the static pressure gas bearing pad and the movable body. The present invention relates to a combination structure with a gap adjusting member for adjusting a gap and a static pressure gas bearing mechanism using the same.

JP-A-8-28564 JP 2000-199522 A Japanese Patent Application Laid-Open No. 2002-349569

  Hydrostatic gas bearings, especially porous hydrostatic gas bearings using porous metal sintered bodies, are known as bearings with excellent high-speed stability, high load capacity, and extremely low movement resistance, and these excellent It is used in many fields because of its advantages. When such a static pressure gas bearing is interposed between the movable body and the fixed body in a pad form (in the present invention, the pad-shaped static pressure gas bearing is referred to as a static pressure gas bearing pad), usually, A static pressure gas bearing pad is arranged with a minute gap between them, for example, a gap of about 5 μm.

  Since this gap greatly affects the bearing rigidity, load capacity and speed characteristics, the static pressure gas bearing pad is located between the movable body and the fixed body via a gap adjustment member that can adjust the gap between the movable body and the movable body. However, the clearance adjustment member usually allows the hydrostatic gas bearing pad to oscillate (swing) and, at the tip of the presser member, so that it does not fall off from the hydrostatic gas bearing pad. And a hydrostatic gas bearing pad via a screw or the like.

  By the way, in the case of such a combined structure of the static pressure gas bearing pad and the gap adjusting member, since screws and the like are used, it takes time for assembly and maintenance, resulting in an increase in cost.

  The present invention has been made in view of the above points, and the object of the present invention is to connect the static pressure gas bearing pad to the static pressure gas bearing pad so as not to drop off without using a screw or the like. Another object of the present invention is to provide a combined structure of a static pressure gas bearing pad and a gap adjusting member capable of reducing the cost, an optimum static pressure gas bearing pad and a gap adjusting member, and a static pressure gas bearing mechanism using the same.

  A static pressure gas bearing pad interposed between the movable body and the fixed body that holds the movable body relative to the fixed body, and a gap between the static pressure gas bearing pad and the movable body is adjusted. The combined structure of the present invention with a gap adjusting member is provided in a hydrostatic gas bearing pad and has a recess having a ring mounting groove, a ring having a diameter expandable mounted in the ring mounting groove, and a gap adjusting member. And a receiving groove for receiving a ring partially protruding from the recess defining surface of the hydrostatic gas bearing pad provided and defining the recess.

  According to the combination structure of the present invention, since the ring having an increased diameter mounted in the ring mounting groove is partially received in the receiving groove, the static pressure gas can be used without using a screw or the like through the ring. The gap adjusting member can be connected to the bearing pad so as not to drop off, and thus the cost can be reduced.

  In the present invention, the recess defining surface includes a cylindrical concave surface and a hemispherical concave surface or a conical concave surface, and the ring mounting groove may be provided between the cylindrical concave surface and the hemispherical concave surface or the conical concave surface. The gap adjusting member is integrally connected to the large-diameter cylindrical portion and the large-diameter cylindrical portion, and is integrally connected to the small-diameter cylindrical portion having a smaller diameter than the large-diameter cylindrical portion and the small-diameter cylindrical portion. It is preferable that a hemispherical portion having a larger diameter than the small-diameter cylindrical portion is provided. In this case, the receiving groove is preferably provided between the large-diameter cylindrical portion and the hemispherical portion. The hemispherical part may be a hemispherical part composed of a perfect circle or a circle approximate thereto, or a hemispherical part composed of a perfect ellipse or an ellipse approximated thereto.

  In a preferred example of the present invention, the hemispherical convex surface of the hemispherical portion is in contact with the concave or conical concave surface of the concave defining surface, and when the concave defining surface includes a cylindrical concave surface and a hemispherical concave surface, The hemispherical convex surface may have substantially the same curvature as the curvature of the concave hemispherical surface of the recess defining surface or a larger curvature. Similarly to the hemispherical portion, the hemispherical convex surface and the hemispherical concave surface may be formed of a perfect circle or a circle approximate thereto or a perfect ellipse or an ellipse approximate thereto, and the conical concave surface is also the same.

  In a preferred example of the present invention, the large-diameter cylindrical portion has a threaded portion on the outer surface thereof, and is screwed to the fixed body via the threaded portion. The ring mounting groove and the receiving groove are each annular, and the static pressure gas bearing pad has a porous surface facing the movable body and a non-porous surface facing the fixed body. And the recess is open in a non-porous surface, the hydrostatic gas bearing pad has a porous metal sintered layer, and one surface of the porous metal sintered layer is It is a porous surface facing the movable body, and the ring is an elastic O-ring.

  As the porous metal sintered layer, a metal powder and an inorganic powder mixed and sintered can be cited as a preferred example, where the metal powder contains at least tin, phosphorus and copper, Furthermore, it is preferable that at least one of nickel and manganese is included, and the inorganic powder includes at least one of graphite, boron nitride, graphite fluoride, calcium fluoride, aluminum oxide, silicon oxide, and silicon carbide. Although it is good to include, this invention is not limited to these.

  The ring is preferably made of an elastic O-ring made of an elastic material as described above, but the present invention is not limited to such a ring, and is elastically expandable and contractible, and is a rigid material. The hemispherical convex surface of the hemispherical portion may be in contact with the hemispherical concave surface of the recess-defining surface as a whole, preferably in a slidable manner, Alternatively, it may partially contact the hemispherical concave surface of the recess defining surface, preferably slidably.

  According to the present invention, it is possible to connect the static pressure gas bearing pad to the static pressure gas bearing pad so as not to drop off without using a screw or the like, and thus to reduce the cost between the static pressure gas bearing pad and the gap adjustment member. It is possible to provide a combined structure, a hydrostatic gas bearing pad and a gap adjusting member optimum for the combined structure, and a hydrostatic gas bearing mechanism using the same.

  Next, the present invention and the best mode for carrying it out will be described in more detail based on the preferred embodiments shown in the drawings. The present invention is not limited to these examples.

  1 to 3, a static pressure gas bearing pad 3 interposed between the movable body 1 and the fixed body 2 to hold the movable body 1 movably in the X direction with respect to the fixed body 2, and a static pressure. A combined structure 6 with a gap adjusting member 5 for adjusting the gap 4 between the gas bearing pad 3 and the movable body 1 is provided in the static pressure gas bearing pad 3 and has a recess 8 having a ring mounting groove 7. , A ring 9 made of an elastic O-ring that can be expanded in diameter and mounted in the ring mounting groove 7, and a recess defining surface 10 of the static pressure gas bearing pad 3 that is provided in the gap adjusting member 5 and that defines the recess 8. And a receiving groove 11 for receiving a ring 9 partially protruding therefrom.

  Each of the movable body 1 and the fixed body 2 is composed of a rectangular plate and a U-shaped rail in the illustrated example, but when the combination structure 6 is applied to, for example, a precision machine tool, The movable body 1 has a form suitable for the work head itself, a base on which the work head is placed, or a work placing base, and the fixed body 2 also holds the movable body 1 having such a form in a movable manner in the X direction. Therefore, the movable body 1 and the fixed body 2 are not limited to a rectangular plate and a rail having a U-shaped cross section, respectively.

  A plurality of static pressure gas bearing pads 3 interposed between the side surfaces 15 and 16 of the movable body 1 and the inner side surfaces 17 and 18 of the fixed body 2, and a bottom surface 19 of the movable body 1 and a base upper surface 20 of the fixed body 2. The plurality of static pressure gas bearing pads 3 interposed between the two are configured in the same manner, and the gap adjusting member 5 mounted on the fixed body 2 corresponding to each static pressure gas bearing pad 3. Are also configured in the same manner, and the combined structures 6 of the static pressure gas bearing pads 3 and the corresponding gap adjusting members 5 are also configured in the same manner. A static pressure gas bearing pad 3 interposed between the side surface 15 of the body 1 and the inner side surface 17 of the fixed body 2 and a gap adjusting member 5 attached to the fixed body 2 corresponding to the static pressure gas bearing pad 3. In addition, these static pressure gas bearing pads 3 and gap adjustment It will be described in detail combined structure 6 with member 5.

  The hydrostatic gas bearing pad 3 includes a disc-shaped back metal 23 having a recess 8 opened at a substantially central portion of a flat surface 22 which is a non-porous surface facing the inner surface 17 of the fixed body 2, and a back metal And a disk-like porous metal sintered layer 25 which is integrally formed and fixed to the other plane of the plate 23 and which forms a gas passage 24 in cooperation with the back metal 23. The high-pressure air supplied to the gas passage 24 via the pipe 26 is ejected toward the side surface 15 of the movable body 1 through the numerous pores of the porous metal sintered layer 25. Thus, the static pressure gas bearing pad 3 has the porous surface 27 facing the side surface 15 of the movable body 1 and the flat surface 22 as the non-porous surface facing the inner surface 17 of the fixed body 2. One flat surface of a porous metal sintered layer 25 obtained by mixing and sintering powder and inorganic powder is a porous surface 27.

  The recess defining surface 10 that defines the recess 8 of the hydrostatic gas bearing pad 3 includes a cylindrical concave surface 31 and a hemispherical concave surface 32 composed of a semispherical concave surface. It is provided between the cylindrical concave surface 31 and the hemispherical concave surface 32 in the Y direction orthogonal to the direction.

  The gap adjusting member 5 that adjusts the size (width in the Y direction) of the gap 4 between the porous surface 27 of the static pressure gas bearing pad 3 and the side surface 15 of the movable body 1 includes a large-diameter cylindrical portion 35, a large-diameter A small-diameter cylindrical portion 36 that is integrally connected to the cylindrical portion 35 and smaller in diameter than the large-diameter cylindrical portion 35 and the cylindrical concave surface 31, and is integrally connected to the small-diameter cylindrical portion 36 and is smaller than the small-diameter cylindrical portion 36. And a hemispherical portion 37 made of a hemispherical portion having a diameter smaller than that of the large-diameter cylindrical portion 35, and the annular receiving groove 11 has a large-diameter cylindrical shape in the Y direction. It is provided between the part 35 and the hemispherical part 37. The large-diameter cylindrical portion 35 may be partially disposed in the recess 8 on the end face 44 side. In this case, the large-diameter cylindrical portion 35 swings (oscillates) the hydrostatic gas bearing pad 3. ) May be smaller than the diameter of the cylindrical concave surface 31.

  The large-diameter cylindrical portion 35 has a screw portion 41 on the outer surface thereof, and is screwed to the fixed body 2 via the screw portion 41, and the gap adjusting member 5 rotates the large-diameter cylindrical portion 35. Thus, the size of the gap 4 between the porous surface 27 of the static pressure gas bearing pad 3 and the side surface 15 of the movable body 1 is adjusted by the advance and retreat. It is like that.

  The hemispherical convex surface 42 formed of a hemispherical convex surface of the hemispherical portion 37 has substantially the same curvature as the curvature of the hemispherical concave surface 32 of the concave defining surface 10 and is slidable on the hemispherical concave surface 32 of the concave defining surface 10. There is overall contact. The hemispherical convex surface 42 may have a larger curvature than the curvature of the hemispherical concave surface 32, and in this case, the hemispherical convex surface 42 is slidably partially in contact with the hemispherical concave surface 32.

  The annular receiving groove 11 is defined by the outer peripheral surface 43 of the small diameter cylindrical portion 36, the annular end surface 44 of the large diameter cylindrical portion 35, and the annular end surface 45 of the hemispherical portion 37.

  According to the static pressure gas bearing mechanism 50 having the above-described combination structure 6, the movable body 1 is moved in the X direction with a gap 4 from the fixed body 2 by the high-pressure air ejected from the porous surface 27 toward the movable body 1. Hold freely. The size of the gap 4 is set to an optimum value by the advancement / retraction of the gap adjustment member 5 in the Y direction. After the optimum value is set, the gap adjustment member 5 cannot be advanced / retreated in the Y direction by the lock nut 51. It is fixed to the fixed body 2.

  By the way, according to the combination structure 6, the ring 9 having an increased diameter that is mounted in the annular ring mounting groove 7 is partially received in the receiving groove 11, and the end surface 45 of the hemispherical portion 37 is engaged with the ring 9. Since the hemispherical portion 37 does not come out from the recess 8, the gap adjusting member 5 can be connected to the static pressure gas bearing pad 3 via the ring 9 so as not to drop out without using a screw or the like. Thus, cost reduction can be achieved. Moreover, in the combination structure 6, since the hemispherical convex surface 42 of the hemispherical portion 37 is slidably in contact with the hemispherical concave surface 32, the static pressure gas bearing pad 3 can be swung (swinged). 4, and the hemispherical portion 37 is elastically pressed against the hemispherical concave surface 32 by the hemispherical convex surface 42 with some elastic force of the ring 9 made of an elastic O-ring. 9 is a damper material (attenuating material), which is preferable since it can effectively suppress the occurrence of oscillation of the hydrostatic gas bearing pad 3.

  Further, according to the combined structure 6, after the ring 9 is fitted in the ring mounting groove 7 in the disassembled state shown in FIG. 3, the hemispherical portion 37 is inserted into the recess 8 and the end surface 45 of the hemispherical portion 37 is engaged with the ring 9. By doing so, it can be easily assembled into the state shown in FIG.

  The ring 9 is preferably an elastic O-ring, but may be an E-ring or C-ring that is a rigid material but can be expanded and contracted as long as it is simply connected. Even if an E-ring or a C-ring is used, the gap adjusting member 5 can be connected to the static pressure gas bearing pad 3 so as not to drop off, thereby reducing the cost.

  Further, the recess defining surface 10 that defines the recess 8 may include a cylindrical concave surface 31 and a conical concave surface 52 as shown in FIG. 4 instead of the cylindrical concave surface 31 and the hemispherical concave surface 32. The recess defining surface 10 as shown in FIG. 4 is preferable because it can be easily formed. In addition, the recess defining surface 10 may be a rectangular tube concave surface instead of the cylindrical concave surface 31.

It is plane explanatory drawing of a preferable example of embodiment of this invention. It is a whole perspective view of the example shown in FIG. FIG. 2 is a partial exploded explanatory diagram of the example of FIG. 1. It is a partial explanatory view of another preferred example of an embodiment of the invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Movable body 2 Fixed body 3 Hydrostatic gas bearing pad 4 Gap 5 Gap adjustment member 6 Combination structure 7 Ring installation groove 8 Recess 9 Ring 10 Recess regulation surface 11 Receiving groove

Claims (5)

  A static pressure gas bearing pad interposed between the movable body and the fixed body that holds the movable body relative to the fixed body, and a gap between the static pressure gas bearing pad and the movable body is adjusted. A ring having a combination structure with a clearance adjustment member, which is provided on a hydrostatic gas bearing pad and has an annular ring mounting groove, and an elastic O-ring that can be expanded in diameter and is mounted in the ring mounting groove And an annular receiving groove that is provided in the gap adjusting member and receives a ring that partially protrudes from the recessed surface of the hydrostatic gas bearing pad that defines the recessed portion. The surface includes a cylindrical concave surface and a conical concave surface, the ring mounting groove is provided between the cylindrical concave surface and the conical concave surface, and the gap adjusting member has a threaded portion on the outer surface and To be screwed to the fixed body through the threaded part The large-diameter cylindrical portion, the small-diameter cylindrical portion that is integrally connected to the large-diameter cylindrical portion and smaller in diameter than the large-diameter cylindrical portion, and the small-diameter cylindrical portion that is integrally connected to the small-diameter cylindrical portion The receiving groove is provided between the large-diameter cylindrical portion and the hemispherical portion, and the hemispherical convex surface of the hemispherical portion is slid onto the conical concave surface of the recess defining surface. A combined structure of a static pressure gas bearing pad and a clearance adjustment member that are in contact with each other.   The combination structure according to claim 1, wherein the hemispherical portion has a diameter smaller than that of the large-diameter cylindrical portion.   The hydrostatic gas bearing pad has a porous surface facing the movable body and a non-porous surface facing the fixed body, and the recess is open in the non-porous surface. Combination structure.   The combination structure according to claim 3, wherein the hydrostatic gas bearing pad includes a porous metal sintered layer, and one surface of the porous metal sintered layer is a porous surface facing the movable body.   A static pressure gas bearing mechanism comprising the combination structure according to any one of claims 1 to 4.

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