Core for a Valve Housing, and Method for Producing the Core

Abstract

A core for casting a valve housing includes at least one first core part which is additively produced, and at least one second core part which is produced without using additive production. The at least one first core part represents at least one pressure chamber or at least one pressure medium channel of the housing which is configured to provide a fluidic connection of a pressure medium source to a pressure medium consumer when the housing is formed using the core. At least one frame-shaped core holder is formed by a first of the at least one second core part when the housing is formed using the core.

Claims

1. A core for casting a valve housing, comprising: at least one first core part which is additively produced; and at least one second core part which is produced without using additive production, wherein the at least one first core part represents at least one pressure chamber or at least one pressure medium channel of the housing which is configured to provide a fluidic connection of a pressure medium source to a pressure medium consumer when the housing is formed using the core, and at least one frame-shaped core holder is formed by a first of the at least one second core part when the housing is formed using the core.

2. The core as claimed in claim 1, wherein the at least one frame-shaped core holder is at least one pressure chamber or at least one pressure medium channel of the housing which is configure to fluidically connect a pressure medium sink.

3. The core as claimed in claim 2, wherein the at least one pressure chamber or at least one pressure medium channels of the housing is the only pressure chamber or pressure medium chamber in the housing configured to fluidically connect the pressure medium sink when the housing is formed using the core.

4. The core as claimed in claim 1, wherein the at least one pressure chamber or at least one pressure medium channel of the housing is the only pressure chamber or pressure medium chamber in the housing configured for fluidic connection to the pressure medium consumer when the housing is formed using the core.

5. The core as claimed in claim 1, wherein the at least one first core part represents a recess of the housing to accommodate at least some section or sections of a valve body when the housing is formed using the core.

6. The core as claimed in claim 5, wherein the at least one second core part represent an at least one extension to the recess when the housing is formed using the core.

7. The core as claimed in claim 6, wherein at least one of: the at least one extension extends on one side of the recess; and the at least one extension comprises a first and second extension, each of the first and second extension extending on respective sides of the recess.

8. The core as claimed in claim 7, wherein the at least one extension sections is represented in a manner connected via a connecting section in the form of a link.

9. The core as claimed in claim 8, wherein at least one of: the at least one extension is represented by the core holder; and the at least one extension and the link are represented by the core holder.

10. The core as claimed in claim 1, wherein the at least one first core part represents at least one pressure chamber or at least one pressure medium channel of the housing which is configured to indicate one of a load pressure, an actuating pressure, and a control pressure when the housing is formed using the core.

11. The core as claimed in claim 1, wherein at least one of all of the pressure chambers and all of the pressure channels of the formed housing are represented by the first and second core part.

12. A method for producing a core for casting a valve housing, comprising: producing by additive production at least one first core part, the at least one fist core part representing at least one pressure chamber or at least one pressure medium channel of the housing which is configured to fluidically connect a pressure medium source to a pressure medium consumer when the valve housing is cast using the produced core; producing at least one second core part without using additive production, wherein at least a first of the at least one second core part represents at least one core holder when the valve housing is cast using the produced core; and connecting the produced at least one first core part and the produced at least one second core part.

13. The method as claimed in claim 12, wherein producing by additive production at least one first core part comprises: producing by additive production at least one first core part that represents a recess of the housing configured to accommodate at least some section or sections of a valve body when the valve housing is cast using the produced core.

14. The method as claimed in claim 13, wherein producing at least one second core part without using additive production comprises: producing at least one second core part without using additive production, wherein the produced at least one second core part represents an extension to the recess.

15. The method as claimed in claim 12, wherein the produced at least one first core part represents at least one pressure chamber or at least one pressure medium channel of the housing which is configured to indicate one of a load pressure, an actuating pressure, and a control pressure when the valve housing is cast using the produced core.

Description

[0039] In the drawings:

[0040] FIG. 1 shows a longitudinal section through a valve housing according to the invention in accordance with one exemplary embodiment,

[0041] FIG. 2 shows a core according to the invention of the housing according to FIG. 1 in a perspective illustration,

[0042] FIG. 3 shows a second core part of the core according to FIG. 2 in a perspective illustration,

[0043] FIG. 4 shows a first core part of the core according to FIG. 2 in a perspective illustration, and

[0044] FIG. 5 shows the core according to FIG. 2 in an exploded view.

[0045] FIG. 1 shows a housing 1, produced according to the invention, of a valve designed as a spool valve, which is cast by means of a core according to the invention which is of multi-part configuration. In this case, all the pressure chambers or pressure medium channels, which are shown without hatching in FIG. 1, are represented by the core. These are: a recess 4, which extends in the direction of a longitudinal axis 2 and in which a valve body for controlling pressure medium connections can be accommodated in a longitudinally movable manner, a high-pressure chamber 6, which is in pressure medium connection with a pressure medium source, in particular with a pump connection (not illustrated) of the housing 1, two working-pressure chambers 8, 10, which are in pressure medium connection with a respective working connection (not illustrated) of the housing 1, two low-pressure or tank-pressure chambers 12, 14, which are connected by means of a connecting section 16 of link-like design, wherein the low-pressure chamber 12 is connected to a low-pressure or tank connection (not illustrated) of the housing 1, and load-indicating and control-pressure channels 18, 20, 22.

[0046] The pressure chambers 6, 8, 10, 12, 14 each extend substantially as radially extended, fully circumferential grooves around the recess 4. The high-pressure chamber 6 is designed to be mirror-symmetrical with respect to a plane of symmetry 3 set perpendicularly to the longitudinal axis 2. The working-pressure chambers 8, 10 are arranged symmetrically with respect to the plane of symmetry 3 on both sides of the high-pressure chamber 6 in the longitudinal direction 2. The same applies to the low-pressure or tank-pressure chambers 12, 14, which are arranged to the outside of the two working-pressure chambers in the longitudinal direction 2. The link 16 is designed to be largely symmetrical with respect to the plane of symmetry 3 and extends over the working-pressure chambers 8, 10 and the high-pressure chamber 6.

[0047] In order to simplify the following description of a casting core according to the invention, its geometries are designated with the same nomenclature and the same reference numerals as the geometries of the housing which are represented by it. For better differentiation, the reference signs of the core are additionally indexed with one, two or three prime symbols (for example 20′, 20″ or 20′″).

[0048] Accordingly, FIG. 2 shows an exemplary embodiment of a core 24′ according to the invention, by means of which the housing 1 is produced according to FIG. 1. Here, the already described geometries 4 to 22 of the housing 1 are represented by the geometries 4′ to 22′ of the core 24′.

[0049] As already mentioned, the pressure chambers 8′, 6′ and 10′ extend in the form of radial extensions of the recess 4′ and each open tangentially into a high-pressure connection P′ and/or into a working connection A′ and B′. According to FIG. 2, the low-pressure chamber 12′ is connected to a tank connection T′. The connections P′, A′, B′, T′ are in this case arranged on a bottom side 35′ of the core 24′.

[0050] The channels 22′ and 26′ each end in control oil connections Y′ and X′ on the bottom side 35′ and in pilot control connections p′ and t′ on the roof section 37′.

[0051] They represent control pressure or control oil channels. The connections X′ and Y′, which are provided for the connection of a control pressure or control oil source, are in this case arranged on the bottom side 35′ of the core 24′. The pilot control connections p′ and t′, which are provided for connecting a pilot control valve, are arranged on the roof section 37′ of the core 24′.

[0052] The core 24′ is divided into different core parts and is made up of these. In particular, those pressure chambers of the housing 1 which, at least in some section or sections, form a pressure medium flow path via which a pressure medium source or hydraulic pump connected to the housing 1 can be connected to the working connections of the housing 1, are in this case to be formed as optimally as possible in terms of flow, with a low pressure loss. In contrast to established production methods for cores, in which their geometric configuration is limited by boundary conditions, such as a necessary demoldability, the additive production method for cores makes it possible to form these geometries in an almost unlimited configuration, and therefore with maximum flow optimization. The pressure chambers or pressure medium channels with these stated high requirements are therefore represented according to the invention by core parts of the core which are produced additively. On the other hand, other chambers or channels which, for example, have to meet lower or no requirements with respect to the geometric shaping and the pressure loss, are represented by core parts of the core which are produced by an alternative method, in particular by means of a conventional core shooting or cold-box method.

[0053] FIG. 4 shows a one-piece first core part 28′ of the core 24′ with the recess 4′, the pressure chambers 6′, 10′, 12′ and the connections A′, P′ and B′. The first core part 28′ thus represents pressure chambers 4′, 6′, 10′, 12′ and pressure medium channels which contribute to the pressure medium connection of the pressure medium source, represented by the high-pressure connection P′, to a consumer, represented by the working-pressure connections A′, B′. The pressure medium connections are formed in cooperation with the valve body of the valve from P′ via 4′ to A′ and from P′ via 4′ to B′ and are to be controlled with correspondingly optimized, minimized pressure loss since the latter always has to be provided by an increased pressure level of the pressure medium source, in particular a hydraulic pump. Owing to these requirements, the first core part 28′ is produced additively.

[0054] The first core part 28′ furthermore has a T-shaped base plate 30′, in which the working connections A′, B′ and the high-pressure connection P′ are based. The base plate 30′ forms a connecting section for insertion into a core holder.

[0055] FIG. 3 shows this core holder as a frame-shaped second core part 32′. This is formed in one piece from a frame 33′, which is closed in the exemplary embodiment. Cylindrical extensions 4″ to the recess 4′ extend inward and along the longitudinal axis 2 from the side walls 31′ of the frame. The respective extension 4″ is adjoined by the pressure chamber 12′ and 14′, respectively. These 12′, 14′ are connected via the link 16′, wherein the low-pressure connection T′ emerges from the pressure chamber 12′ and is based in a bottom section 35′ of the frame 33′.

[0056] According to FIG. 3, the second core part 32′ thus only has pressure chambers which do not have to meet the above-described high requirements for a pressure loss to the same extent. It is therefore produced by an alternative method, i.e. non-additively, by means of a core shooting method.

[0057] For positionally accurate insertion of the first core part 28′, the second core part 32′ according to FIG. 3 has a T-shaped connecting section 34′, which is modeled after the base plate 30′ of the second core part 28′ according to FIG. 4. The latter 30′ is, in principle, a T-shaped insert, designed to match the T-shaped connecting section 34′, in the form of a recess in the second core part 32′.

[0058] According to FIG. 3, in each case one receptacle, in particular in the form of a quarter of a circle, is provided laterally on the inside of the pressure chambers 12′, 14′, facing the recess 4′, as a connecting section for connection to the first core part 28′. This has corresponding projections as connecting sections.

[0059] According to FIG. 3, further first core parts 18′ and 20′ are connected to the core holder 32′. The control or actuating pressure medium channels represented by them have high requirements for a loss-free pressure medium connection of an actuating pressure medium source connected to the housing 1, represented in the exemplary embodiment illustrated by the connections a′ and b′ (cf. FIG. 2), to an active surface of the valve body provided in the recess 4. In order to be able to meet these requirements by means of an optimally designed channel geometry, the first core parts 18′ and 20′, as already the first core parts 22′, 26′ and 28′, are also produced additively.

[0060] According to FIGS. 3 and 5, the first core parts 18′ and 20′ each have, on the side of the respective extension 4″, a foot-shaped connecting section 18″ or 20″ via which they are pushed into a connecting section, designed as a receptacle, of the extension 4″. The respective other end section of the first core part 18′ or 20′ has a foot-shaped connecting section 18″ or 20′″, into which the connection a′ or b′ opens. The foot-shaped connecting sections 18″, 20′″ are each pushed into a corresponding recess on the roof section 37′ of the frame 33′. The connections a′ and b′ are thus arranged on the roof section 37′ of the frame 33′ of the core 24′.

[0061] FIG. 5 shows the core 24′ with all the already mentioned first core parts 18′, 20′, 22′, 26′, 28′ and the second core part 32′, the core holder, in an exploded view.

[0062] A multi-part core is disclosed which represents pressure chambers of a housing of a valve, in particular of a directional control valve configured as a spool valve, wherein, according to the invention, at least those of the pressure chambers of the housing via which a pressure medium source can be fluidically connected to a pressure medium consumer with as little loss as possible, in particular with low pressure loss, are represented by an additively produced core part of the core. Other pressure chambers of the housing, which must meet comparatively low requirements in respect of loss or pressure loss, are, on the other hand, produced by an alternative method, that is to say non-additively, that is to say by means of another method.