Valve assembly

Abstract

Valve assembly for damping pressure oscillations in a hydraulic system, comprising a valve housing (5) in which a longitudinal channel (6) connecting a valve inlet (9) with a valve outlet (13) is formed, with a closing element (4) inserted in the longitudinal channel (6), which is acted upon by a closing spring (1) in the direction of a valve seat (12) formed in the valve housing (5), wherein a hydraulic orifice cross-section in the form of a bypass channel (10) is arranged in parallel to the closing element (4) to bypass the closing element (4), wherein the bypass channel (10) is produced by a partial plastic deformation of the valve seat (12), characterized in that the bypass channel (10) is embossed by a perpendicular introduction of a wire into the sealing surface of the valve seat (12) in the form of the contour of the wire, which has a round or polygonal wire cross-section, wherein the wire is made of a material,the hardness of which is increased compared to the material hardness of the valve seat (12), wherein the valve seat (12) for the formation of the bypass channel (10) consists of a plastically deformable free-cutting steel which, after the production of the bypass channel (10), is provided with a surface hardening in the area of ​​the sealing surface of the valve seat (12).

Description

[0001] The invention relates to a valve assembly for damping pressure oscillations in a hydraulic system, according to the preamble of patent claim 1.

[0002] A valve assembly of the specified type is already known from DE 10 2013 202 588 A1. This valve assembly consists of a cartridge-shaped valve housing in which a closing body, loaded by a closing spring, interacts with a valve seat in a manner dependent on differential pressure. To bypass the closing body, a hydraulic orifice in the form of a bypass channel can be arranged in parallel to the closing body, if desired or required.

[0003] Furthermore, AT 408 480 B discloses a throttle check valve in which a notch is pressed into the valve seat, which acts as a bypass channel. The notch is created without clamping using a forming tool. DE 102 36 314 A1 discloses a seat valve of an injection system in which a throttle is formed as a notch in the seat valve, wherein the notch has a rectangular, semicircular, or oval cross-section. Furthermore, DE 10 2011 078 250 A1 discloses a valve assembly which also comprises a valve seat with an orifice passage that acts as a throttle.

[0004] Now, with regard to the arrangement of an orifice, the object of the present invention is to further develop the valve assembly of the type mentioned at the outset in such a way that the bypass channel is integrated within the valve seat with the least possible manufacturing effort.

[0005] This object is achieved according to the invention for a valve assembly of the specified type with the characterizing features of patent claim 1.

[0006] Further features and advantages of the invention will become apparent from the following description of several embodiments with reference to drawings.

[0007] They show: Fig. 1 the valve assembly according to the invention in longitudinal section in an overall view of all functionally relevant components, Fig. 2 an excerpt from the Fig. 1 illustrated valve assembly to show the valve seat and the bypass channel in an enlarged view, Fig. 3 a view of the Fig. 2 in the area of ​​the bypass channel marked interface AA.

[0008] The Fig. 1 shows a longitudinal section through a detailed overall view of the basic construction of the valve assembly according to the invention, which is preferably used to damp pressure oscillations in a brake hydraulic system of a motor vehicle, for which purpose a hydraulic orifice is preferably arranged in the form of an orifice notch in the valve seat 12, which is formed at the lower end of a longitudinal channel 6 penetrating vertically through the valve housing 5, so that regardless of the position of the closing body 4, as a result of the orifice shown as a bypass channel 10, a permanent connection from the valve inlet 9 in the direction of the valve outlet 13 is created in the valve assembly.

[0009] The closing body 4, which interacts with the valve seat 12, is acted upon by a closing spring 1, which holds the closing body 4 in its basic position on the valve seat 12, so that in the basic position only the cross-section of the bypass channel 10 is exposed. Lifting of the closing body 4 from the valve seat 12 thus occurs exclusively as a function of the differential pressure, ie provided that the hydraulic pressure acting on the closing body 4 in the valve inlet 9 is greater than the spring pressure of the closing spring 1, which is designed as a cylindrical spring, for example. The closing spring 1 is supported with its first coil end on the closing body 4 and with its second coil end, which is arranged diametrically opposite the first coil end, on the lower horizontal end of the valve housing 5.

[0010] The valve housing 5 is constructed in two parts, consisting of an upper housing part and a lower housing part, which are connected to one another at least positively, preferably non-positively. The upper housing part consists of a thick-walled blank made of free-cutting steel, preferably by cold-forming or contour-turning, on the underside of which the valve seat 12 is formed. In contrast, the closing body 4, together with the closing spring 1, is housed in the lower housing part, which is cup-shaped and formed from a deep-drawn sheet. Furthermore, the cup-shaped lower housing part has at least one outlet opening in its outer surface, which is preferably produced by stamping, to form the valve outlet 13.

[0011] In order to minimize the noise emission of the closing body 4 by suitable damping of its vibration behavior, an elastic friction element in the form of an O-ring 3 is arranged downstream of the closing body 4 in the valve housing 5, which is frictionally received between the valve housing 5 and the closing body 4.

[0012] The closing body 4 is essentially a ball valve and therefore at least spherical or designed as a spherical cap, to which a cylindrical pin 7 is connected as a homogeneous component. At a distance from the spherical cap, the pin 7 extends partially into the closing spring, wherein the pin 7 has a collar 2 outside the closing spring 1, against which both the closing spring 1 and the O-ring 3 are supported under preload within an annular groove 8 formed in the collar 2. The collar 2 thus advantageously enables the vibration-damping friction function of the O-ring 3 and the closing function of the closing spring 1 in a simple manner. Furthermore, the pin 7 extending below the collar 2 into the closing spring 1 prevents the cylindrically wound closing spring 1 from buckling.

[0013] For example, the bypass channel 10 is manufactured particularly simply and precisely by partially plastically deforming the valve seat 12, without the risk of chip formation in the area of ​​the valve seat 12. The bypass channel 10 is designed as a notch, groove, or groove arranged parallel to the closing body 4 directly in the valve seat 12, which is calibrated to a defined orifice cross-section by means of the plastic deformation of the valve seat 12, so that when the closing body 4 is in the closed position at the valve seat 12, the valve inlet 9 is permanently connected to the valve outlet 13 via the longitudinal channel 6 in the valve housing 5 via the orifice cross-section.

[0014] As shown by the Fig. 2, the plastic deformation of the valve seat 12 is carried out by vertically feeding a stamping tool into the sealing surface of the valve seat 12, while simultaneously calibrating the orifice cross-section required for the bypass channel 10, the cross-section of which at the interface AA is Fig. 3. To achieve the simplest possible design of the bypass channel 10, the invention utilizes a wire pressed into the sealing surface of the valve seat 12 instead of a complex stamping tool, so that the contour of the wire stamped into the valve seat 12 defines the bypass channel 10 with the aperture cross-section representative of the wire cross-section. To implement the stamping function, the wire is hardened or made of a material whose hardness is significantly higher than the material hardness of the valve seat 12.

[0015] The valve seat 12 is thus basically made of a material with a lower hardness than the wire to form the bypass channel 10, in particular of a plastically deformable free-cutting steel, which is then provided with a wear-resistant surface hardening after the bypass channel 10 has been impressed into the area of ​​the sealing surface of the valve seat 12.

[0016] The Fig. 2 illustrates the design of the longitudinal channel 6 in the area of ​​the valve seat 12 as a stepped bore, so that the valve seat 12 is formed by a bore step of the stepped bore, in which a permanent fluidic connection between the valve inlet 9 and valve outlet 13 is established by means of the calibrated bypass channel 10.

[0017] As further stated in the Fig. 2, the bore step has a funnel-shaped chamfer 11 which widens in the direction of the closing body 4 in order to form a suitable sealing surface for the valve seat 12 and which, as shown in the illustration, is radially widened on the right-hand side in a locally limited manner to a defined orifice cross-section of the bypass channel 10, essentially as a result of the plastic deformation described above. To ensure unhindered flow around and to accommodate the closing body 4 in the longitudinal channel 6, the stepped bore below has a larger diameter in the direction of the valve outlet 13 than in the area of ​​the valve inlet 9, so that a connection between the valve inlet 9 and the valve outlet 13 is guaranteed at all times, regardless of the stroke position of the closing body 4.

[0018] Finally, the Fig. 3 the cross-section of the Fig.2, from which the deformation of the valve housing 5 as a result of the bypass channel 10 embossed into the valve seat 12 can be seen. List of reference symbols 1 closing spring 2nd Bund 3 O-ring 4 locking bodies 5 valve housing 6 Longitudinal channel 7 cones 8 ring groove 9 Valve inlet 10 Bypass channel 11 Chamfering 12 Valve seat 13 Valve outlet

Claims

[1] Valve assembly for damping pressure oscillations in a hydraulic system, comprising a valve housing (5) in which a longitudinal channel (6) connecting a valve inlet (9) to a valve outlet (13) is formed, with a closing body (4) inserted in the longitudinal channel (6) which is acted upon by a closing spring (1) in the direction of a valve seat (12) formed in the valve housing (5), wherein a hydraulic orifice cross-section in the form of a bypass channel (10) is arranged in parallel to the closing body (4) to bypass the closing body (4), wherein the bypass channel (10) is produced by a partial plastic deformation of the valve seat (12), characterized byin that the bypass channel (10) is embossed in the shape of the contour of the wire by a vertical feed of a wire into the sealing surface of the valve seat (12), which wire has a round or polygonal wire cross-section, wherein the wire is made of a material whose hardness is increased compared to the material hardness of the valve seat (12), wherein the valve seat (12) for forming the bypass channel (10) consists of a plastically deformable free-cutting steel which, after the production of the bypass channel (10), is provided with a surface hardening in the region of the sealing surface of the valve seat (12). [2] Valve assembly according to claim 1, characterized by that the bypass channel (10) is manufactured without cutting in the valve seat (12). [3] Valve assembly according to claim 1 or 2, characterized bythat the bypass channel (10) is designed as a notch, groove or groove arranged parallel to the closing body (4) in the valve seat (12), which permanently connects the valve inlet (9) via the longitudinal channel (6) in the valve housing (5) to the valve outlet (13) during the closed position of the closing body (4) on the valve seat (12). [4] Valve assembly according to claim 1, characterized by that the longitudinal channel (6) in the region of the valve seat (12) is designed as a stepped bore, so that the valve seat (12) is formed by a bore step in which a permanent fluidic connection between the valve inlet (9) and valve outlet (13) is established by means of the bypass channel (10). [5] Valve assembly according to claim 4, characterized byin that, in order to form a sealing surface of the valve seat (12), the bore step has a chamfer (11) which is widened in a funnel shape in the direction of the closing body (4) and which is radially widened in a locally limited manner to a defined orifice cross-section of the bypass channel (10). [6] Valve assembly according to claim 5, characterized by that for unhindered flow around and for receiving the closing body (4) in the longitudinal channel (6), the stepped bore in the area of ​​the valve outlet (13) has a larger diameter than in the area of ​​the valve inlet (9).

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