The present invention relates to a hydrostatic profile rail guide in which a guide carriage is mounted hydrostatically on a guide rail.
A hydrostatic profile rail guide has become known, for example, from WO 2004/020852 A1, in which a guide rail designed with an approximately T-shaped cross-section is surrounded by the guide carriage. The guide carriage has a back and legs located on both sides of the guide rail and adjoining the back in one piece, so that the guide carriage has an approximately U-shaped cross-sectional profile. The free ends of each leg are provided with screw-on flanges which spring toward one another so that the T-shaped guide rail is surrounded.
In these known hydrostatic profile rail guides, pressure pockets for building up a hydrostatic pressure between the guide rail and the guide carriage are provided in a known way on said guide carriage. Hydraulic fluid is pumped into the pressure pockets via an external pump, so that a pressure cushion is built up between the guide carriage and the guide rail. The hydraulic fluid flows out via gaps which are connected hydraulically to the pressure pockets. The gaps are delimited by gap faces which are formed on the guide carriage and on the guide rail.
Furthermore, this known hydrostatic profile rail guide is provided with a drainage in order to receive hydraulic fluid emerging from the gaps. The drainage is connected to a return duct or a reservoir so that the hydraulic fluid can be supplied to the pump again and pumped anew into the pressure pockets of the hydrostatic profile rail guides.
Furthermore, a seal is provided, which ensures that this known hydrostatic profile rail guide is oil-tight. This seal is arranged effectively between the guide carriage and the guide rail and has side portions and head portions. In each case at least one of the side portions of the seal which extend along the guide rail is arranged between each leg of the guide carriage and the guide rail. In each case, at least one of the head portions of the seal is arranged transversely to the guide rail on both head sides of the guide carriage. This seal ensures that no oil escapes undesirably even when the pump is switched off and the hydrostatic profile rail guide is at a standstill.
The side portions and the head portions of the seal must cooperate with one another such that the oil-tightness described is ensured. Various proposals as to a technical solution have been made toward this. Thus, it has been proposed to glue to one another or press against one another mutually adjacent ends of the head portions and of the side portions of the seal or to produce a seal entirely in one piece. However, all these technical solutions are complicated, oil-tightness remaining challenging at the transition between the head portion and the side portion of the seal.
The object of the present invention is to specify a hydrostatic profile rail guide according to the precharacterizing clause of Claim 1, in which the escape of hydraulic fluid from the hydrostatic profile rail guide is ruled out in a simple way, or, in other words, in which oil-tightness is ensured.
According to the invention, this object is achieved by means of the hydrostatic profile rail guide according to Claim 1. Since the side portions of the seal are formed by side seals arranged on the guide rail and the head portions of the seal are formed by head seals arranged on the guide carriage, the problem of the connection of ends of the head seal and of the side seal is avoided. It was found that sliding contact is sufficient for oil-tightness precisely at the transition between the side seals and the head seal.
A further advantage of the invention may be seen in that it is no longer necessary to provide side portions of the seal on the guide carriage. The guide carriage can consequently be produced more simply, since, for example, grooves for the reception of sealing cords are dispensed with. Omitting the side portions of the seal on the guide carriage affords a further advantage from another aspect; hydrostatic profile rail guides are often used alternatively to rolling profile rail guides. This means that hydrostatic profile rail guides have to be produced in the standard construction space of rolling profile rail guides. DIN 645-1 provides standardized construction series of which the largest are 15, 20, 25, 30, 35, 45, 55, 65. In the smaller construction series of 15 to about 30, the available space for forming the pressure pockets and the gaps connected to the pressure pockets and for drainage is very limited because of the small spatial dimensions. The omission, for example, of a groove designed for receiving a side seal on the guide carriage, therefore means that there is additional construction space, for example, for enlarging the pressure pockets.
In the hydrostatic profile rail guide according to the invention, each gap can be delimited in a known way by gap faces of the guide carriage and of the guide rail.
Preferably, the two legs of the guide carriage are in each case provided at their free ends with a sealing face which faces the guide rail and extends between the two axial ends of the leg and against which the assigned side seal bears. In a similar way to a lip seal, here too, oil-tight contact between the side seal and the sealing face of the leg is ensured. The side seal may be designed as a sealing cord or else as a lip seal.
Guide rails for hydrostatic profile rail guides according to the invention preferably have an approximately anvil-shaped rail head, there being formed between the rail head and a rail foot a contracted foot portion, as far as which the free end of the leg of the guide carriage reaches when the guide carriage is pushed onto the guide rail. In this case, the foot portion of the guide rail is provided with the side seal according to the invention. The side seal extends along the guide rail over the entire travel of the guide carriage.
For the satisfactory positioning and reliable holding of the side seal, the guide rail may be provided with longitudinal grooves for receiving the side seal.
In a hydrostatic profile rail guide according to the invention, the seal may be formed preferably from two longitudinal seals and two head seals, the head seals adjoining the longitudinal seals and forming a seal arranged around the drainage and closed so as to be fluid-tight.
The invention is explained in more detail below by means of an exemplary embodiment depicted in a total of four figures in which:
The guide rail 2 has an approximately anvil-shaped rail head 8 and a rail foot 9, a contracted foot portion 10 being formed between the rail foot 9 and the rail head 8. The rail head 8 is provided on its two longitudinal sides in each case with two bearing faces 11, 12 which are arranged at an acute angle to one another and which extend along the longitudinal axis of the guide rail 2.
It may be gathered from
In order to ensure that the hydraulic fluid can circulate in a closed circuit, the hydrostatic profile rail guide according to the invention is provided with a seal 18. This seal 18 is of continuous design, in that the seal 18 completely surrounds the drainage 17. Here, surround is understood to mean that the hydraulic fluid can leave the drainage solely via the paths provided and therefore does not leak out of the hydrostatic profile rail guide undesirably.
The seal 18 according to the invention is composed of side seals 19 and head seals 20. It may be gathered particularly from
In the exemplary embodiment, the side seal 19 is formed by a cord seal which is received in a longitudinal groove 21 formed in the foot portion 10 of the guide rail 2. These side seals 19 extend over the entire travel of the guide carriage 1.
The two head seals 20 are arranged in the guide carriage 1, specifically in one of the two head pieces 3, 4, each.
It may be gathered, furthermore, from
Number | Date | Country | Kind |
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10 2008 047 298.0 | Sep 2008 | DE | national |