WO2008034519A1 - Valve arrangement for a hydrostatic machine, in particular for an axial piston machine - Google Patents

Abstract

The invention relates to a valve arrangement (1) for a hydrostatic machine, having a valve holding part (2) and an add-on part (3) which bear against one another at contact faces (2a, 3a) which face toward one another, having a valve guide (4) which is arranged in a holding hole (5) which is arranged in the valve holding part (2) and, therein, opens out toward the add-on part (3), and having a line duct (11) which extends longitudinally in the valve guide (4) and emerges at the end side at the end facing toward the add-on part (3) and extends further in the add-on part (3). Here, a radial annular seal (25) which surrounds the line duct (11) is arranged between the valve guide (4) and the add-on part (3). In order to improve the valve arrangement, the valve guide (4) and/or the add-on part (3), in its region situated opposite the valve guide (4), have in each case one compressed axial deformation region which is compressed by a clamping force which braces the valve guide (4) and the add-on part (3) against one another.

Description

VALVE ASSEMBLY FOR A HYDROSTATIC MACHINE, ESPECIALLY FOR ONE

axial piston

The invention relates to a valve arrangement according to the preamble of claim 1 or 3.

Previous valve arrangements comprise three components of the hydrostatic machine positioned in their installed position, namely a valve receiving part 0 and an attachment facing each other

Abutment surfaces abut each other, and a valve guide which is inserted in a receiving hole of the valve receiving part so that their attachment end facing in the region formed by the two contact surfaces des5 valve receiving part and the attachment

Divisional joint is located. In this case, the valve guide along its central axis, which is also the central axis of the receiving hole, in the direction away from the attachment direction by a first transverse surface of the receiving hole and0 a second transverse surface adjacent thereto at

Limited and positioned valve guide and limited and positioned in the direction of the attachment facing direction by a third transverse surface on the valve guide and a fourth transverse surface on the attachment. 5

This axial fit of the Venti1führung between the valve receiving part and the attachment is prefabricated with a clearance fit to ensure during assembly that the valve guide between the 0 valve receiving part and the attachment fits. Through this clearance fit ensures that the valve receiving part and the attachment with their contact surfaces abut each other, which is essential for a stable and tight installation position. 5

It has been found in practice, however, that the valve guide due to their axial installation play in the functional operation of the hydrostatic machine by pressure changes of the hydraulic medium or Vibrations of the machine causes small longitudinal movements, which leads to sliding movements and an associated abrasion, when the ring seal is arranged on the circumference of the valve guide between this and the valve receiving part as an axial seal. A comparable stress by compression exists even if a radial seal in the region of the dividing joint is arranged between the valve guide and the attachment. In a radial seal, the associated sealing ring is due to the small axial movements of the

Valve guide alternately applied with respect to its axial compression, namely by the axial movement, the compression is alternately increased and decreased. Although abrasion is lower in this stress, but it also leads to a permanent load to a deterioration of the radial seal and its life.

But even if, on the one hand, no axial seal between the valve guide and the valve receiving part is present and / or on the other no radial seal between the valve guide and the attachment is present, it can come especially with their size rapidly changing pressure changes to a so-called valve rattling of the valve assembly , where the

Valve ratchet is increased by additional vibration movements as associated valve body.

The invention has for its object to improve the valve assembly, in particular to extend the life of an axial seal and / or a radial seal of the valve assembly. In addition, the aim is to simplify the manufacture of the valve assembly and to make it cost-effective. Furthermore, the sealing of the valve guide should be improved, in particular between it and the attachment, in the region of the dividing joint. This object is solved by the features of claim 1 or claim 3. Advantageous developments of the invention are described in the subclaims.

In the valve arrangements according to the invention according to claim 1 or 3, the valve guide and / or the attachment in its region opposite the valve guide in each case a compressed axial deformation region, which is compressed by a clamping force. This results in a play-free seat of the valve guide between the valve receiving part and the attachment, whereby axial movements, for. As vibration, the Venti1führung are avoided in functional operation of the hydrostatic machine. Consequently, an axial ring seal and / or a radial ring seal of the valve guide are unimpaired and extended life.

In addition, embodiments of the invention lead to an improvement of the radial seal between the valve guide and the attachment. In this case, due to the deformation takes place a special areal adaptation of the abutting surfaces of the valve guide and the attachment, this adjustment further improves the radial seal.

In the context of the invention, the at least one deformation region can be arranged in the valve guide and / or in the region of the attachment opposite the valve guide. This depends on the strength of the materials of the valve guide and the

Attachment. The deformation region according to the invention forms under the tension force on the part whose material strength is lower. When the valve guide and the attachment are made of the same material, the deformation area is formed in both adjoining areas of these parts.

The clamping force according to the invention is generated by an associated clamping device of the hydrostatic machine. It is particularly advantageous to dimension the aforementioned cross-sectional size as a function of the existing clamping force so that when mounting and clamping the Ventilaufnähmeteils and the fixture against each other, the inventive local deformation of

Deformation is achieved. An associated clamping device is preferably formed by a screw connection between the valve receiving part and the attachment. In such a screw connection, the effect according to the invention is achieved automatically when mounting the hydrostatic machine, namely during standard screwing of the attachment to the valve receiving part.

A compression of the deformation region in the elastic region has the advantage that after disassembly and reassembly, for. B. after a repair or maintenance, the deformation area expands and can be compressed again and the effect of the invention can again fully unfold.

In a compression and deformation in the plastic region axial distance between its axial support surfaces, the valve assembly is reusable after disassembly due to a residual elasticity of the deformation region.

Another advantage of the embodiment of the invention is that the above-described improved radial seal is very insensitive, especially against high pressure loads of the existing hydraulic fluid. Therefore, the embodiment of the invention is particularly suitable for a valve assembly used in high pressure.

In addition, the embodiment of the invention is particularly suitable for an axial piston machine, in which due to the piston movements in the functional mode vibrations occur, the above-described Induce movements of the valve guide or force it under the simultaneous effect of pressure changes.

Below are advantageous embodiments of a valve arrangement according to the invention based on

Embodiments and simplified drawings explained in more detail. It shows

1 shows a valve arrangement according to the invention in an intermediate assembly position in axial section.

Figure 2 shows the valve assembly in the final assembly position. and

Fig. 3, the valve assembly in a modified

Design in the final assembly position.

The valve arrangement, denoted by 1 in its entirety, comprises three main parts, namely a valve receiving part 2, an attachment 3 and a valve guide 4, which is spatially positioned between the valve receiving part 2 and the attachment 3 and in a receiving hole 5 with a small clearance from that of the attachment 3 facing bearing surface 2a of the valve receiving part 2 is inserted. In the partially assembled shown in Fig. 1

State of the valve assembly 1 is the attachment 3 with its the valve receiving part facing bearing surface 3a not on the contact surface 2a, but it has the axial distance a, which will be explained in more detail. The attachment 3 is connected by a clarified by two arrows tensioning device S with the valve receiving part 2, which preferably formed by a screw 6 with a plurality of spaced screws, the screw holes in the attachment 3 and the valve receiving part 2 through and through

Knitting point lines are illustrated. The clamping force generated by the clamping device S is illustrated by axial arrows. The receiving hole 5 has at an axial distance b from the contact surface 2a to a first transverse surface 8, which is formed by a shoulder surface between an opening on the contact surface 2a enlarged hole portion 5a and extending from this tapered hole portion 5b. At the first transverse surface 8, the valve guide 4 abuts with a second transverse surface 9, which is also arranged by a step surface between an extended guide body portion 4b and a tapered guide body portion 4c. The extended guide body portion 4b fits into the extended hole portion 5a with little play. The tapered guide body portion 4c is smaller than the tapered hole portion 5b, so that there is an annular channel therebetween, which forms a channel portion IIa to be described later.

The valve guide 4 has, at its end facing the attachment 3, a third transverse surface 12 formed by its end face, with which it rests against an axially opposite fourth transverse surface 13 of the attachment 3, which is a part of the abutment surface 3a. These transverse surfaces 12, 13 are abutting annular surfaces, which will be explained in more detail.

In the embodiment, a valve 14 of the valve assembly 1 in the valve guide 4 is formed so that it forms a prefabricated valve assembly 15 with the valve guide 4, which can be mounted by their insertion into the receiving hole 5.

In the embodiment, the valve 14 is a check valve whose valve body 14a is resiliently biased by the flow force or pressing force of the fluid against the edge of a valve opening 17.

In addition, this elastic bias could still be supported by the force of a spring. In the embodiment, the valve body 14a is disposed on the extended guide body portion 4b opposite end of the valve guide 4 and formed by a tapered valve head 14b, which is biased against the edge of the valve opening 17, of which a

Channel section IIb extending in the attachment 3 away from the direction. The flow channel section 18a is part of a hydraulic line 11, which continues as an annular channel IIa and surrounds the tapered guide body section 4c, by radial

Channels 11c extends into the valve guide 4, continues axially in this as formed therein longitudinal channel section Hd and opens out at the associated end face of the valve guide 4 and continues in an axially opposite channel section He in the attachment 3, which terminates at the contact surface 3a.

In the area of the valve assembly 15 or the valve guide 4 or its valve guide body, a filter 23 is preferably used which, in the exemplary embodiment, is seated in the passage section Hd.

The valve guide 4 is sealed in the valve arrangement 1 by an axial ring seal 24 and / or a radial annular seal 25. The axial ring seal 24 is arranged between the extended guide body portion 4b and the wall of the hole portion 5a and formed by one or two sealing rings 24a, 24b, which sit in an annular groove 24c, which is preferably arranged in the lateral surface of the valve guide 4.

The radial annular seal 25 is arranged at the end face between the valve guide 4 and the attachment 3 in the region of the dividing joint 26 formed by the abutment surfaces 2a, 3a between on the one hand the attachment 3 and on the other hand the valve receiving part 2 and the Venti1führung 4.

The radial ring seal 25 is connected by a sealing ring 25 a, z. As an O-ring, formed in a preferably outwardly opening annular groove 25b is arranged, which surrounds a preferably coaxial annular portion 4d of the valve guide 4, whose preferably circular outer cross-section has the dimension designated c.

The invention aims to improve the seal between the valve guide 4 and the attachment 3. This is achieved by a clamping force which is directed transversely to the dividing joint 26 between these parts and biases these parts in the region of their transverse surfaces 12, 13 against each other. The surface pressure on the transverse surfaces 12, 13 is so great that a deformation region 30 shown in FIG. 2, which is arranged in an area of the attachment 3 opposite the valve guide 4, or a deformation region 30 (FIG. 3) arranged in the valve guide Compression is deformed and that is elastically deformed or beyond plastically deformed.

This is achieved in that with respect to the distance b between the shoulder surface 8 of the valve Aufnähmeteils 2 and its contact surface 2a, the valve guide 4 is prefabricated with respect to their axial distance between their transverse surface 9 and the attachment 3 end facing with a distance a corresponding oversize (Fig 1) or the transverse surface 13 of the attachment 3 with respect to its contact surface 3a is prefabricated with a projection corresponding to the distance a (not shown).

In the embodiment, the valve guide 4 is formed with this excess, as shown in FIG. 1, wherein the attachment 3 has a continuous planar contact surface 3a, of which the annular transverse surface 13 is a part.

Due to this prefabricated oversize, when the valve receiving part 2 and the attachment 3 are clamped together by the tensioning device S into the final assembly position according to FIG. 2, in which the contact surfaces 2a, 3a abut each other, the transverse surfaces 12, 13 pressed against each other. In each case, in the region of the associated transverse surfaces 12, 13, the compressed and deformed deformation region 30 is formed, which can also be arranged on both parts. The position of the deformation region 30 at the one part and / or at the other part is determined by the strength of the materials of the valve guide 4 and the attachment part 3. The deformation region 30 forms on the part with the lower material strength. If both parts have the same material, then the deformation region 30 can arise in the regions of the transverse surfaces 12, 13 of both parts. In the present embodiment, the material of the attachment 3 is softer than the material of the valve guide 4. Therefore, formed during clamping of the

Deformation region 30 in the region of the transverse surface 13 and thus in the attachment 3 from.

The resistance force, which is opposite to the clamping force, is determined by the size of the transverse surfaces 12, 13. If a clamping force of an existing clamping device S is to be utilized to produce the deformation in the deformation region 30, then the size of the transverse surfaces 12, 13 is to be adapted to lower consideration of the existing clamping force. This can be achieved by a

Adjusting the cross-sectional dimensions or diameter d and / or e of the ring section 4d and / or the channel section He determine.

By the size of the distance a corresponding oversize can determine whether the deformation region 30 is elastically or plastically deformed or is. Ie. The larger the oversize is selected, the greater the deformation or compression in the deformation area 30.

In the embodiment according to the invention thus the valve guide 4 is not only positioned axially immovable in the receiving hole 5, but it is also the seal between the Venti1führung 4 and the attachment 3 improved or created a radially effective annular seal 31 (Fig. 2). The tightness of this seal is greater, the greater the clamping force and the deformation generated thereby. Due to the deformation, the transverse surfaces 12, 13 get into a particularly adapted

Surface contact to each other, whereby the tightness is particularly large.

In the context of the invention, therefore, this radial ring seal 31 based on surface pressure of the abutting transverse surfaces 12, 13 can replace the radial annular seal 25. Particularly advantageous is the arrangement of the two radial annular seals 25, 31, in particular when the duct 11 is a high-pressure duct, through which in the

Functional operation a hydraulic medium with high pressure is passed. The radial ring seal 31 is particularly suitable for receiving such pressures, in particular high pressures, and thereby relieving the radially outer ring seal 25 and extending its service life, the life of the ring seal 31 also being very long.

In the embodiment of FIG. 3, in which the same or comparable parts are provided with the same reference numerals, and showing the valve assembly 1 in the final assembly state of FIG. 1, the ring portion 4 d or at least one end portion of the ring portion 4 d by an additional component, namely a Ring 4e, formed or replaced, which shortened at a corresponding to its axial dimension

Valve guide body is attached and surrounds the channel section Hd. The lateral surface of the ring 4e may be adapted to the inner dimension of the sealing ring 25a so that it forms a seating surface for the sealing ring 25a.

The advantage of this embodiment is that the ring 4e can be formed with a material that is independent of the material of the rest of the valve guide body, and chosen harder or softer In the latter case, the deformation region 30 results in the region of the transverse surface 12, ie 4e in the abutment region of the ring.

The invention is not limited to the illustrated embodiments. For example, instead of an O-ring also a differently formed elastic seal can be used. The elastic seal may be made of rubber or a synthetic polymer material. All described or drawn features can be combined with each other in the invention.

Claims

claims 1. Valve arrangement (1) for a hydrostatic machine, in particular an axial piston machine, with a valve receiving part (2) and an attachment (3), which lie against each other on mutually facing contact surfaces (2a, 3a), - A valve guide (4) arranged in a valve receiving part (2) and therein to Attachment (3) out opening receiving hole (5) is arranged, - and in the valve guide (4) extending longitudinally and at the attachment (3) end facing the front side emerging and the attachment (3) further extending duct (11), wherein a radial annular seal (25) surrounding the power channel (11) is arranged between the valve guide (4) and the attachment (3), and - the valve guide (4) and / or the attachment (3) being in its (Fig. 4) each having a compressed axial deformation region (30), which is compressed by a clamping force that biases the valve guide (4) and the attachment (3) against each other. 2. Valve arrangement according to claim 1, characterized in that the valve guide (4) in the attachment (3) facing away from the direction by a transverse surface (8) of the Valve receiving part (2) is supported and the clamping force by a valve receiving part (2) and the attachment (3) against each other biasing clamping device (S) is compressed. 3. Valve arrangement (1) for a hydrostatic machine, in particular an axial piston machine, with a valve receiving part (2) and an attachment (3), which lie against each other on mutually facing contact surfaces (2a, 3a), - A valve guide (4) arranged in a valve receiving part (2) and therein to Attachment (3) out opening receiving hole (5) is arranged, - and in the valve guide (4) extending longitudinally and at the attachment (3) end facing the front side emerging and the attachment (3) further extending duct (11), - Wherein the valve guide (4) in the attachment (3) facing away from the direction by a transverse surface (8) of the valve receiving part (2) is supported and the Ventilaufnähmeteil (2) and the attachment (3) by a clamping device (S) are clamped against each other , and - Wherein the valve guide (4) and / or the attachment (3) in its the valve guide (4) opposite region each having a compressed axial deformation region (30) which is compressed by the clamping force of the tensioning device (S). 4. Valve arrangement according to one of the preceding claims, characterized in that the deformation region (30) is elastically deformed in the elastic range of its material or plastically deformed beyond the elastic limit of its material. 5. Valve arrangement according to claim 3 or 4, characterized in that the valve guide (4) arranged by an arranged at its periphery axial ring seal (24) and / or between the valve guide (4) and the attachment (3) and the duct ( 11) surrounding radial annular seal (25) is sealed. 6. Valve arrangement according to one of the preceding claims, characterized in that the tensioning device (S) is formed by a screw connection (6) between the valve receiving part (2) and the attachment part (3). 7. Valve arrangement according to one of the preceding claims, characterized in that the valve guide (4) has an opening therein power channel section (lld) surrounding annular portion (4d) which surrounds the radial ring seal (25), preferably on the ring portion (4d) sits , 8. Valve arrangement according to claim 7, characterized in that the radial size of the deformation region (30) by the outer cross-sectional size (d) of the ring portion (4d) and the cross-sectional size (e) in the attachment (3) continuing line duct portion (llle) is determined , 9. Valve arrangement according to one of the preceding claims, characterized in that the attachment (3) consists of a softer material than the valve guide (4) and the deformation region (30) in the valve guide (4) opposite region of the attachment (3) is arranged , 10. Valve arrangement according to one of the preceding claims, characterized in that in the attachment part (3) opposite region of the valve guide (4) a duct portion (lld) surrounding ring (4e) is arranged, against which the attachment (3). 11. Valve arrangement according to claim 10, characterized in that the material of the ring (10e) has a same strength as that of the valve guide (4) or of the attachment part (3) or one of the strength of the material the valve guide (4) or the material of the attachment (3) has different strength. 12. Valve arrangement according to one of the preceding claims 2 to 11, characterized in that the valve guide (4) with a transverse surface (9) on the transverse surface (8) of the valve receiving part (2) is supported and with a distance (c) between its transverse surface (9) and its attachment (3) facing the end is prefabricated, which is greater than the distance (b) of the transverse surface (8) of the valve receiving part (2) of its contact surface (2a). 13. Valve arrangement according to one of the preceding claims, characterized in that in the bottom of the receiving hole, a valve opening (17) is arranged, with which a valve body (14 a) cooperates, in the Venti1führung (4) mounted axially displaceable and by the flow force or Compressive force of the fluid against the valve opening (17) is biased.