Hydrostatic profile rail guide

p0001The present invention relates to a hydrostatic profile rail guide, with a guide carriage which can be hydrostatically supported on a guide rail.

p0002Out <patcit id="pcit0001" dnum="DE3831676C1"><text>DE 38 31 676 C1</text></patcit> For example, a hydrostatic profile rail guide is known in which a guide carriage is mounted hydrostatically on a guide rail. The guide rail is provided with a central surface extending along its longitudinal axis and with two upper bearing surfaces which are arranged at both longitudinal sides of the central surface and are arranged at an angle to this central surface. A lower bearing surface, which is arranged inclined relative to this upper bearing surface and inclined to the central surface, is provided below each upper bearing surface. Viewed in the cross-section through the profile rail guide, a triangle is stretched by a first parallel straight line, which is imagined to the central surface of the guide rail, by a second parallel straight line which is imagined to the upper bearing surface and by a third parallel straight line which is parallel to the lower bearing surface. In this triangle, an angle a is formed between the first and second straight lines. In this triangle, an angle γ is also formed between the first and the third straight line.

p0003Below these two upper and lower bearing surfaces provided in the head region of the guide rail, two emergency running surfaces are provided in the foot region of the guide rail relative to the two longitudinal sides thereof, which limit an angle β which is at most 90 ° with the lower bearing surfaces of the head region.

p0004The guide carriage placed on the guide rail is also provided with upper and lower bearing surfaces which cooperate with the upper and lower bearing surfaces of the guide rail. Between the respective bearing surfaces of the guide rail and the guide carriage, pressure pockets are formed, in which a hydrostatic pressure can be built up. The hydrostatic pressure allows the guide carriage to be stored perfectly on the guide rail.

p0005The back of the guide carriage is usually provided with a clamping surface for clamping a machine part, for example. The machine part can be a tool or any other component. These machine parts generally have a flat bearing surface for resting on the clamping surface of the back.

p0006The possible applications of such hydrostatic profile rail guides can be limited in that the legs of the guide carriage can bend under an applied load. In this case, the pressure pads built up in the pressure pockets can not possibly be maintained, so that a perfect operation of the hydrostatic profile rail guide is not guaranteed. Such problems can be remedied, for example, by increasing the outer proportions of the guide carriage so that the legs of the guide carriage become stiffer. However, such changes have the disadvantage that an exchange of profile rail guide guides against hydrostatic profile rail guides is not possible. According to DIN 645-1, the external geometry of profile rail guide guides is specified. Known hydrostatic profile rail guides can not be used as a substitute for common profile rail guide systems, since a change in the outer proportions is necessary for guaranteeing perfect operation at comparable loads of these hydrostatic profile rail guides, so that DIN 645-1 is not complied with.

p0007A hydrostatic profile rail guide according to the preamble of claim 1 is made of <patcit id="pcit0002" dnum="US5980110A1"><text>US 5,980,110 A1</text></patcit> known.

p0008The object of the present invention is to provide a hydrostatic profile rail guide according to the features of the preamble of claim 1, in which a faultless operation is ensured.

p0009According to the invention, this object is achieved by the hydrostatic profile guide according to claim 1. The clamping surface is provided on each side of the longitudinal center axis of the guide carriage with a clamping strip or clamping edge between which the clamping surface is lowered or concavely curved in the longitudinal direction of the guide rail. When the machine part is tensioned on this clamping surface, it is tightened, for example, with screws. This concavely-shaped clamping surface can be planed under this tightening of the machine part, the back of the back bending itself around a bending axis parallel to the longitudinal center axis of the guide carriage, the free ends of the two legs pivoting somewhat towards one another. When the machine is screwed firmly onto the clamping surface of the guide carriage, a gap between the guide rail and the guide carriage in the area of ​​the bearing surfaces can be very small, for example 5 to 10 μm. If, however, this hydrostatic profile rail guide is pressurized, for example 100 bar, compressive forces act between the bearing surface of the guide rail and the guide carriage, which result in a bending of the two limbs of the guide carriage against its prestressing. Under this counter-bending deflection of the two limbs, an ideal gap size is now established, which can be, for example, 25 μm. This means that the desired gap dimensions between the bearing surfaces of the guide rail and of the guide carriage can be maintained under the intended operating loads even under unfavorable stress of the hydrostatic profile rail guide. There are no increased gap dimensions, so that no undesirably high volume flow of hydraulic fluid occurs. This advantageous effect is made possible by the concave-shaped clamping surface of the guide carriage, which allows a specifically prestressed biasing in the back of the guide carriage, which counteracts an undesired abutment of the limbs of the guide carriage. A defined bending of the back about a bending axis, which is intended along the guide rail, is possible with the profile rail guide according to the invention.

p0010When the machine part is placed on the guide carriage as described above, a distance is formed between the plane bearing surface of the machine part and the lowered mounting surface of the back. If the machine part is then braced with the guide carriage as described above, the back is pulled with its clamping surface in the direction of the plane bearing surface of the machine part. Under this planarization of the concave or lowered mounting surface of the back, the two limbs of the guide carriage pivot toward one another as described above.

p0011Preferably, the guide carriage is provided along its longitudinal center axis with a plurality of tapped holes arranged one behind the other or projecting from the plane of the clamping surface in order to screw the machine part to the guide carriage. The screw forces acting on the screw connection engage with a lever arm on the two limbs of the guide carriage which corresponds precisely to the distance between the clamping edge and the longitudinal center axis.

p0012For the perfect design of the hydrostatic profile rail guide according to the invention, it may be expedient to define a first plane E1 in which the two clamping strips or edges are arranged. The lowered clamping surface then lies in a plane E2, which is spaced from the plane E1. In the case of a concave-shaped clamping surface, this concave clamping surface is tangential to this plane E2. The distance between these two planes E1 and E2 is then set such that this distance is returned to zero under a clamping of the machine part onto the guide carriage. Thus, with the adjusted distance h, a stop dimension can be defined so that, after reaching this stop, the gap dimension between the bearing surfaces of the guide rail and the guide carriage has a small distance. Only after the hydrostatic profile rail guide according to the invention with pressure has been applied, the desired gap dimension between these bearing surfaces is established.

p0013The invention is explained below with reference to an exemplary embodiment illustrated in a total of five figures. Show it:<dl id="dl0001"><dt>FIG</dt><dd>A hydrostatic profile rail guide according to the invention in a perspective view,</dd><dt>FIG</dt><dd>A cross-section through the hydrostatic profile rail guide according to the invention <figref idrefs="f0001">FIG</figref>,</dd><dt>FIG</dt><dd>A further cross-section through the profile rail guide according to the invention,</dd><dt>FIG</dt><dd>The profile rail guide according to the invention with the machine part clamped on, pressureless,</dd><dt>FIG</dt><dd>The profile rail guide according to the invention <figref idrefs="f0003">FIG</figref>But pressurized, and</dd><dt>FIG</dt><dd>A cross-section through a known profile rail guide.</dd></dl>

p0014The <figref idrefs="f0001 f0002 f0003 f0004">Figures 1 to 5</figref> The guide rail 1, which is mounted on a guide rail 2, is hydrostatically supported. The guide rail 2 has a head portion facing the guide carriage 1 and a foot portion which faces a machine part, not shown here, on which the guide rail 2 is fastened. At its head section, the guide rail 2 is provided with a central surface 3 along the longitudinal axis of the profile rail guide. The guide rail 2 is provided with a plurality of through-openings 4 arranged along the guide rail, by means of which fastening screws (not shown) for fixing the guide rail to the machine part mentioned above are provided. These through openings 4 break through the central surface 3 of the guide rail 2.

p0015The guide rail 1 is provided at its head portion with two upper bearing surfaces 5 and two lower bearing surfaces 6. The upper bearing surfaces 5 are flat; They are arranged inclined relative to the central surface 3, the upper bearing surface 5 being arranged on one side of the central surface 3 and the other upper bearing surface 5 being arranged on the other longitudinal side of the central surface 3. The lower bearing surfaces 6 are arranged below the upper bearing surfaces 5. These lower bearing surfaces 6 are arranged inclined both to the central surface 3 and to the upper bearing surfaces 5.

p0016<figref idrefs="f0002">FIG</figref> Shows the hydrostatic profile rail guide according to the invention in cross-section. It can be seen here that the central surface 3 is arranged parallel to a foot surface 7 of the guide rail 2, this foot surface 7 being the bearing surface of the guide rail 2 for the machine part not shown here.

p0017A first parallel straight line G1, which is imagined to the middle face 3, and a second parallel line G2, which is imagined with respect to the upper bearing face 5, and a third parallel line G3, which is intended for the lower bearing face 6, tension a triangle. In this triangle, an angle α is formed between the first and second straight lines G1 and G2. An angle γ is formed between the first and third straight lines G1, G3. The angle α is set to values ​​between 10 ° to 45 ° inclusive and the angle γ is set to values ​​of 20 ° to 55 ° inclusive. An angle δ is formed at the intersection of the second and third straight lines G2, G3, which can be determined purely mathematically from the two angles α and y mentioned at the beginning. With these angular regions, on the one hand an optimum distribution of forces on the guide rail 2 and on the guide carriage 1 is set. On the other hand, it has been found that the proportions of the guide carriage and the guide rail can be adjusted in these suggested angular ranges in such a way that the requirements of DIN 645-1 can be met, the load capacity of the hydrostatic profile rail guide according to the invention being comparable to a profile rail guide of the same size.

p0018Of the <figref idrefs="f0002">FIG</figref> It can also be seen that the straight line G1 is arranged at a parallel distance from a clamping surface 8 of the guide carriage 1, tools being, for example, placed on this clamping surface 8 and fastened to the guide carriage 1. This clamping surface 8 is concavely curved according to the invention, as described below.

p0019Further details on the guide carriage 1 are shown in FIG <figref idrefs="f0002">FIG</figref> . The guide carriage 1 has two legs 10 which are integrally connected to one another by a back 9 and which engage around the guide rail 2. On its side facing the guide rail 2, the backrest 9 is provided with two upper bearing surfaces 11 which are arranged opposite the two upper bearing surfaces 5 of the guide rail 2 and are arranged parallel to the upper bearing surfaces 5 of the guide rail 2. These upper bearing surfaces 11 are inclined in opposite directions. On the other hand, the back 9 is provided with the already mentioned clamping area 8 according to the invention.

p0020Each leg 10 of the guide carriage 1 is also provided with a lower bearing surface 12, which is arranged opposite the lower bearing surface 6 of the guide rail 2 and is arranged parallel thereto. The two lower bearing surfaces 12 are inclined in opposite directions and are arranged in each case inclined relative to the upper bearing surface 11 as well as to the clamping plane 8.

p0021<figref idrefs="f0003">FIG</figref> 1 shows a cross-section through the hydrostatic profile rail guide according to the invention, wherein the sectional guide shows pressure pockets 13, 14 formed between the upper and lower bearing surfaces 5, 6, 11, 12 of the guide carriage 1 and the guide rail 2. Each of these four pressure pockets 13, Is provided with its own flow control valve (not shown).

p0022Of the <figref idrefs="f0002">FIG</figref> It can be seen that the clamping surface 8 is concavely curved. In this exemplary embodiment according to the invention, additional grooves 8a are formed, which are formed parallel to the longitudinal center axis of the hydrostatic profile rail guide. However, it is sufficient to form the concave-shaped clamping surface 8 shown here without these grooves 8a.

p0023The concave clamping surface 8 touches a plane E1. On both longitudinal sides of the guide carriage, clamping edges 15 are formed, on which a machine part to be screwed initially comes into abutment. These two clamping edges 15 lie in a plane E2 which is arranged parallel to the plane E1. A distance h is formed between these two planes E1 and E2.

p0024Along the longitudinal center axis of the hydrostatic profile rail guide, the guide carriage 1 is provided with a plurality of threaded bores 16. <figref idrefs="f0001">FIG</figref> Shows these threaded bores in a perspective illustration. The guide carriage 1 is designed in such a way that the back 9 is bent in the direction of this machine part by screwing the machine part, which is not shown here, with the guide carriage 1. This means that the distance h between these two planes E1 and E2 is returned to zero during screwing of the machine part to the guide carriage. When the clamping surface 8 is recessed, a gap S between the bearing surfaces of the guide rail 2 and the guide carriage 1 is reduced in the region of the lower bearing surfaces 6 because the two legs 10 pivot with their free ends towards each other when the machine part is screwed to the guide carriage 1 becomes.

p0025<figref idrefs="f0003">FIG</figref> Shows the hydrostatic profile rail guide according to the invention with a indicated machine part 17, which is already screwed tightly to the guide carriage 1. A bearing surface 17a of the machine part 17 is provided, against which the clamping surface 8 of the guide carriage 1 rests. It can be seen from the figure that the distance h between these two planes E1 and E2 has been returned to zero. Of the<figref idrefs="f0003">FIG</figref> It can also be seen that the gap dimension S is reduced in the region of the free limb ends in the region of the lower bearing surfaces 6.

p0026In the representation according to <figref idrefs="f0004">FIG</figref> The profile rail guide according to the invention was designed according to FIG <figref idrefs="f0003">FIG</figref> Pressurized, for example 100 bar. Of the<figref idrefs="f0004">FIG</figref> It can now be seen that an ideal gap dimension S, which is approximately 25 μm, is set under this applied pressure in the region of the lower bearing surfaces. The enlargement of this gap dimension in relation to the gap dimension according to FIG<figref idrefs="f0003">FIG</figref> Results from the prevailing pressure forces in the bearing gap, compressive forces pressing against the limbs 10 and bending them. The hydrostatic profile rail guide according to the invention is designed in such a way that, during operating pressures and operating loads, a bending of the two limbs is limited to an allowable gap dimension S.

p0027<figref idrefs="f0004">FIG</figref> Shows a conventional hydrostatic profile rail guide in which a clamping surface 18 of the guide carriage 1 is merely flat. In the case of a pressureless hydrostatic profile rail guide, a given gap dimension S is established for the machine part 17, which is screwed firmly to the guide carriage 1, as shown in FIG<figref idrefs="f0004">FIG</figref> Is indicated. If this conventional hydrostatic profile rail guide is then pressurized, the two limbs 10 of the guide carriage 1 are bent away from one another. This means that gap dimension S increases, which in the<figref idrefs="f0004">FIG</figref> Is indicated by a dashed line of the guide carriage. However, this increase in the gap dimension S can undesirably result in an inadmissibly high volume flow of hydraulic fluid.

Reference list

p0028<tables id="tabl0001" num="0001"><table frame="none"><tgroup cols="2" colsep="0" rowsep="0"><colspec colnum="1" colname="col1" colwidth="14mm" /><colspec colnum="2" colname="col2" colwidth="32mm" /><tbody><row><entry>1</entry><entry>Management wagon</entry></row><row><entry>2</entry><entry>guide rail</entry></row><row><entry>3</entry><entry>area</entry></row><row><entry>4</entry><entry>through hole</entry></row><row><entry>5</entry><entry>upper bearing surface</entry></row><row><entry>6</entry><entry>lower bearing surface</entry></row><row><entry>7</entry><entry>foot area</entry></row><row><entry>8th</entry><entry>clamping surface</entry></row><row><entry>8a</entry><entry>grooves</entry></row><row><entry>9</entry><entry>move</entry></row><row><entry>10</entry><entry>leg</entry></row><row><entry>11</entry><entry>upper bearing surface</entry></row><row><entry>12</entry><entry>lower bearing surface</entry></row><row><entry>13</entry><entry>printing bag</entry></row><row><entry>14</entry><entry>printing bag</entry></row><row><entry>15</entry><entry>clamping edge</entry></row><row><entry>16</entry><entry>Tapped hole</entry></row><row><entry>17</entry><entry>Machine part</entry></row><row><entry>18</entry><entry>clamping surface</entry></row></tbody></tgroup></table></tables>