SI23775A - Electromagnetic valve to control the devices in the hydraulic circuits - Google Patents

Abstract

A hydraulic circuit components controlling electromagnetic valve (1), which is furnished with at least three connecting openings (A, B, P, T), which are arranged corresponding to each desired function of the valve as such, as well as with an electromagnet (4,4'), which is arranged in/on said housing (1) and is adapted to cooperate with said redirecting member (2). Both the housing (1) at least in the area of the internal sealing surface (30) of the chamber (3) with diameter (D3), and also said redirecting member (2) at least of its external hydraulic sealing surface (20) with diameter (D2), consist of quenched steel, wherein the gap (C) there-between, namely the half difference between the characteristic diameter (D3) of the sealing surface (30) of the chamber (3) and the characteristic diameter (D2) of the sealing surface (20) of the redirecting member (2), should be between 1 micrometer and to 5 micrometer at maximum.

Description

Solenoid valve for controlling devices in hydraulic circuits

The invention in the field of mechanical engineering belongs to the mechanical elements and devices for ensuring the proper functioning of the devices, namely electromagnetic multipath or multi-position valve and solenoid valve for supply or diversion of the hydraulic medium.

The invention is based on the problem of how to design a solenoid valve for diverting a hydraulic medium for the purpose of controlling the operation of at least one hydraulic circuit of the device incorporated on the basis of the signal received, whereby water, optionally in combination, is used as a hydraulic medium in the hydraulic circuit. with environmentally friendly anti-freeze additives and the operating pressure of the hydraulic medium in such a circuit should range from at least 50 bar to at least about 250 bar.

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The prior art includes a number of solenoid valve solutions for controlling the hydraulic circuits of the devices involved. For example, one such solution was published as WO 2005/059420. In all cases, it is a hydraulically sealed housing comprising at least an approximately cylindrical chamber inside, in which a sealed shut-off body is inserted against the wall of said chamber, which can be moved in at least two or more positions along the chamber. On the other hand, the hydraulic housing is provided in the wall of the housing, through which a hydraulic line, available outside the housing, is connected to the interior of said chamber, so that, depending on the position of said shut-off body, the hydraulic fluid at each time is accessible through certain connections, but not through the remaining ones. In this way, it is possible to connect certain hydraulic lines to each hydraulic circuit through such a valve, and by changing the position of said shut-off body, then to change the combinations of connections between said hydraulic lines optionally. In each hydraulic circuit, said hydraulic lines can be selected in a suitable manner so that, for example, one of them leads to a reservoir of hydraulic medium, the other to a high-pressure pump, the third to a hydraulic cylinder, the fourth and the next to, for example, the remaining control valves that may be available. The movement of said closure body can generally be performed entirely mechanically, e.g. by means of levers, restraints and other mechanisms, but also electrically, e.g. by means of electric motors, or in particular by means of at least one electromagnet. When moving with the help of an electromagnet, the latter is mounted in / on the housing, and the said shut-off body is connected to an angle which the electromagnet pulls or pushes from one position to another. In such a case, a spring or a further electromagnet can be provided to move the shut-off body, which can be activated after deactivation of the first electromagnet of one electromagnet, or the opposite can be achieved by changing the polarity. As a hydraulic medium, it is well known in the •

hydraulic circuits for serious commercial purposes, hydraulic oil is mostly used, and the operating pressure generated by hydraulic pumps is between 50 and 260 bar. As a hydraulic medium, the oil exhibits good hydraulic as well as tribological characteristics, but due to its viscosity, it is exposed to heat and, consequently, to aging. changing the properties. On the other hand, oil is relatively expensive, and in particular the use of hydraulic oil can be problematic in the context of the risk of environmental pollution. On the one hand, there is the problem of efficient collection and recovery of spent oil, and on the other hand, the possibility of leaking or even leaking oil from the hydraulic circuit into the environment, which can occur in the event of accidents or breakdowns. This possibility is especially present in various machines and devices used in the natural environment outside the industrial areas, e.g. in agriculture, forestry, fisheries, construction and similar industries.

The invention relates to an electromagnetic valve for controlling devices in hydraulic circuits, wherein such valve comprises a hydraulically sealed housing, inside which it is available to receive a cylindrically shaped shut-off body with a characteristic diameter on the hydraulic sealing surface and the available hydraulic medium. and a substantially cylindrical shaped chamber with a characteristic diameter on the hydraulic sealing surface. In this case, said housing is provided with at least three valve functions provided for each time and, according to the respective positions of the shut-off body, correspondingly arranged connections for providing hydraulic connection between said chamber and the available hydraulic lines, depending on the respective position of said shut-off body. Through these connections, the valve is connected to the remaining components of the hydraulic circuit that is available at all times. Furthermore, at least one solenoid is provided in / on the housing which is adapted to cooperate with the aforementioned • ·

to the shut-off bodies in order to move the shut-off body in one or the other direction along said chamber, optionally for emergency purposes, for this purpose at least one spring mounted in the housing for closing or respectively. opening said fittings on the housing in each predetermined position of said shut-off body, and such valve being provided for operation in a high-pressure hydraulic circuit in which the nominal pressure of the hydraulic medium ranges from at least 50 bar to at least 250 bar.

According to the invention, it is contemplated that in such a valve, both said housing, at least in the region of its hydraulically sealing inner surface of the chamber with characteristic diameter, as well as said shut-off body, at least in the region of its external hydraulic sealing surface with characteristic diameter, consist of hardened steel, wherein Their mutual clearance corresponding to half the difference between said characteristic diameter of the sealing surface of the chambers and said characteristic diameter of the sealing surface of the closure organ is from 1 pm to a maximum of 5 pm. At the same time, water is used as the pressure hydraulic medium in the chamber, as well as through the above connections on the housing with the said chamber of hydraulically connected lines, which is optionally mixed with the highest antifreeze.

In a preferred embodiment of the invention, said housing, at least in the region of its hydraulically sealing inner surface of the chamber of characteristic diameter, consists of hardened martensitic stainless steel, in particular AISI 440B (X90CrMoV18) or AISI 440C (X105CrMol7). In addition, at least in the area of its external hydraulic sealing surface with a diameter, the shut-off body consists of hardened martensitic stainless steel, preferably again AISI 440B (X90CrMoV18) or AISI 440C (X105CrMol7).

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According to the invention, when the valve is intended for installation in a hydraulic circuit with a nominal pressure of the hydraulic medium between 50 and 150 bar, the clearance between the chamber surface and the surface of the shut-off body is from 1 pm to 4 pm.

It is further provided according to the invention that when the valve is intended to be installed in a hydraulic circuit with a nominal pressure of the hydraulic medium between 150 and 250 bar, the clearance between the chamber surface and the surface of the shut-off body is from 1 pm to 3 pm.

It is further contemplated according to the invention that when the valve is intended to be installed in a hydraulic circuit with a nominal pressure of hydraulic medium above 250 bar, the clearance between the chamber surface and the surface of the shut-off body is from 1 pm to 2 pm.

Further, in the preferred embodiment of the valve according to the invention, at least two electromagnets are provided in the housing, which are electrically powered and controlled in such a way that after receiving the signal they generate each of their magnetic fields, the magnetic field of one of the electromagnets being pushed in the respective direction in each case, at the same time, the magnetic field of the rest of the electromagnets pulls the said shut-off body in the same direction. Preferably, the shut-off body is supported on each side of the chamber by at least one pressure spring, which is designed to create force in the axial direction of the shut-off body.

Further, a filter for filtering the hydraulic medium is provided in the area of at least one of the connectors, and the antifreeze agent selected from the group consisting of ethanol, ethylene glycol and propylene glycol for addition to water as the hydraulic medium is provided.

The invention will now be explained in more detail by way of an exemplary embodiment illustrated in the accompanying drawing showing

FIG. 1 shows, in a longitudinal section, in a diametrical plane, one of the possible embodiments of a valve according to the invention, namely a 3/4 valve with four connections and three positions;

FIG. 2 is a diagram of the first of the two valve utilization variants of FIG. 1 in hydraulic circuits;

FIG. 3 is a schematic diagram of the remaining of the two variants of use of the valve according to FIG. 1 in hydraulic circuits;

FIG. 4 is a flow chart between the chamber wall and the surface of the shut-off body of the valve according to the invention.

The solenoid valve (Fig. 1) for controlling devices in hydraulic circuits generally comprises a hydraulically sealed housing 1, inside which there is a chamber 3 adapted to receive a cylindrically shaped shut-off body 2 with a characteristic diameter D ₂ per hydraulic seal. the outer surface 20 as well as a suitable hydraulic pressure medium, which in this case is plain water, to which, if necessary, the frost-free additive is preferably mixed with the conditions of use.

Said chamber 3 is substantially cylindrical in shape, and its characteristic diameter on the hydraulic sealing inner surface 30 is in FIG. 1 denoted by D ₃ • ·

Ί

The enclosure 1 is provided with at least three of the valve functions provided for each time and therefore according to the respective positions of the shut-off body) appropriately spaced connections A, B, P, T to provide a hydraulic connection between said chamber 3 and the available hydraulic lines depending on the position selected at each time. of said shut-off body 2. Through said connectors A, B, P, T, the valve is interconnected with the remaining components of the hydraulic circuit available at each time.

In addition, at least one solenoid 4, 4 'is provided in / on the housing 1, which is adapted to cooperate with said shut-off body 2 in order to move the shut-off body 2 in one direction or another along said chamber 3 optionally for emergency purposes in the shutter 1 fitted with at least one 5, 5 'spring for closing or. opening said terminals A, B, P, T at housing 1 in each predetermined position of said closure body 2.

Connection P is a pressure connection that is hydraulically connected to a high pressure hydraulic pump not shown through a hydraulic line. Terminals A and B are working connectors that are connected, for example, via hydraulic lines. with hydraulic cylinder (s). Connector T is a return connector that is e.g. hydraulically connected to the unpressured reservoir of the pressure medium via a return hydraulic line.

In FIG. 2 and 3 are schematically illustrated variants of this type of valve. In FIG. 2 is a zero-position blocked valve illustrated. The left position corresponds to the position of the closure body 2 after moving it according to FIG. 1 to the left and the right position after moving the body 2 according to FIG. 1 to the right. In FIG. 3 is again a schematically illustrated variant of a zero-relief valve with connections A, • ·

B and Γ related. The choice of each of said variants according to FIG. 2 and 3 are possible based on the choice of the shape of the shut-off body 2.

An embodiment of FIG. 1 - 3 therefore represents the so-called 3/4 control valve or. manifold, meaning it is a valve with three positions and four ports A, B, P, T.

Such a valve is intended to be operated in a high-pressure hydraulic circuit in which the nominal pressure of the hydraulic medium ranges from at least 50 bar to at least 250 bar.

According to the invention, it is provided that both said housing 1, at least in the region of its hydraulic sealing inner surface 30 of chamber 3 with diameter D _3, as well as said closure body 2, at least in the area of its outer hydraulic sealing surface 20 with diameter D ₂ , consist of hardened steels having a mutual gap C corresponding to half the difference between the characteristic diameter D _{3 of the} sealing surface 30 of the chamber 3 and the characteristic diameter D _{2 of the} sealing surface 20 of the shut-off body 2 ranges from 1 pm to a maximum of 5 pm. At the same time, plain water is provided as the hydraulic fluid in the chamber 3 as well as through the connections A, B, P, T in the housing 1 with said chamber 3 of the hydraulically connected lines, which is optionally sprayed with the highest antifreeze.

In a preferred embodiment of the invention, said housing 1, at least in the area of its hydraulically sealing inner surface 30 of chamber 3 of diameter D _3, consists of hardened martensitic stainless steel, in particular, for example, AISI 440B (X90CrMoV18) or AISI 440C (X105CrMol7). Also, the closure body 2, at least in the area of its outer hydraulic sealing surface 20 of diameter D _2, consists of hardened martensitic stainless steel, preferably AISI440B (X90CrMoV18) or AISI 440C (X105CrMol7). The choice of these materials is also a priority because of the effective cooperation with the available ones.

AISI 440B stainless steel (DIN X90CrMoV18) is a martensitic steel with a high content of up to 0.9% carbon, 18% chromium, 1.1% molybdenum, 0.1% vanadium and up to 1.0% silicon and manganese.

The clearance C between chamber 3 and shut-off body 2 is illustrated in FIG. 4, and for practical application of the invention for the above defined materials, the surface 30 of the chamber 3 and the surface 20 of the closure body 2 are determined as follows.

When the valve according to the invention is intended for installation in a hydraulic circuit with a nominal pressure of the hydraulic medium between 50 and 150 bar, the clearance C between the surface 30 of the chamber 3 and the surface 20 of the shut-off body 2 is from 1 pm to 4 pm.

When said valve is intended for installation in a hydraulic circuit with a nominal hydraulic medium pressure between 150 and 250 bar, the clearance C between the surface 30 of the chamber 3 and the surface 20 of the shut-off body 2 is from 1 pm to 3 pm.

However, where the valve is intended to be installed in a hydraulic circuit with a nominal hydraulic medium pressure greater than 250 bar, the clearance C between the surface 30 of the chamber 3 and the surface 20 of the shut-off body 2 is from 1 pm to 2 pm.

In or. Box 1 further provides at least two electromagnets 4 ', 4', which are electrically powered and operated in such a way that, upon receipt of the appropriate signal, they each generate their own magnetic field, the magnetic field of one of the electromagnets being 4, 4 '). 2 pushes in the respective direction in each case, while at the same time the magnetic field of the rest of the electromagnets 4, 4 'is pulled by said locking body 2 in the same direction. In this case, the closure body 2 is supported on each side of the chamber by at least one pressure spring 5, 5 ', which is designed to generate force in the axial direction of the closure body 2, as in Figs. 1 illustrated with arrows.

The selection of said materials of the shut-off body 2 and the enclosure 1 or. at least the inner surface 30 of chamber 3 is also preferred because of the effective co-operation with electromagnets 4, 4 'available at all times.

Where a hydraulic device for the installation of a valve according to the invention is intended to operate at temperatures below freezing water, a mixture of ordinary water and an anti-freeze additive is used as the hydraulic pressure medium, said antifreeze being selected from the group formed by ethanol (C ₂ H ₅ OH), ethylene glycol (C ₂ H ₄ (OH) ₂ ) and propylene glycol (C ₃ H ₆ (OH) ₂ ). Propylene glycol, which is used inter alia in the cosmetic and food industries, is harmless to health and is therefore ecologically acceptable as an additive even in the event of a leakage of a hydraulic medium into the environment, e.g. due to failure or damage to the hydraulic circuit.

Ordinary water, optionally mixed with an anti-freeze additive, is therefore a very suitable high-pressure hydraulic medium whose compressibility is less than that of hydraulic oil, while its kinematic viscosity varies considerably less than that of oil as the temperature changes. Also, the remaining traits and phenomena, e.g. The pH, water hardness, microbial content and amount of dissolved air can, in practice, be monitored to the extent that simple measures and adherence to the basic operating instructions are provided to ensure that •

smooth operation of the valve and also of the entire hydraulic system under the conditions of regular use previously described.

In view of the foregoing, an optional filter for filtering the hydraulic medium, i.e. water, may be provided, optionally, in the area of at least one of ports A, B, P, T, and preferably of the return line T. Optionally, other aids and water treatment devices can be installed in the hydraulic circuit.

Claims (12)

PATENT APPLICATIONS A solenoid valve for controlling devices in hydraulic circuits, comprising a hydraulically sealed housing (1) inside which is available to receive a substantially cylindrical shut-off body (2) with a characteristic diameter (D ₂ ) on the hydraulic sealing surface (20) ) and the hydraulic fluid which is available at each time, and a substantially cylindrical shaped chamber (3) of characteristic diameter (D ₃ ) on the hydraulic sealing surface (30), provided with said housing (1) having at least three valve functions provided for each time and thus with respect to the respective positions of the shut-off body (2), with appropriately arranged connections (A, B, P, T) to provide a hydraulic connection between said chamber (3) and the hydraulic lines available at each time, depending on the respective position of said shut-off body (2), through the aforementioned connections (A, B, P, T), the valve is connected to the remaining k components of the hydraulic circuit in each case, and wherein at least one electromagnet (4, 4 ') is provided in / on the housing (1), adapted to cooperate with said shut-off body (2) in order to move the shut-off body (2) to one or the other direction along said chamber (3) optionally for emergency use for this purpose in the housing (1) of at least one spring (5, 5 ') to be closed or closed. opening said connectors (A, B, P, T) on the housing (1) in each predetermined position of said shut-off body (2), and such valve being provided for operation in a high-pressure hydraulic circuit in which the nominal pressure of the hydraulic medium is from at least 50 bar to at least 250 bar, characterized in that both said housing (1) is at least in the region of its hydraulically sealing inner surface (30) of the chamber (3) with diameter (D ₃ ) as well as said closure body (2) at least in the area of its external hydraulic sealing surface (20) of diameter (D ₂ ), consist of hardened steel, with their mutual play (C) corresponding to half the difference between the characteristic diameter (D ₃ ) of the sealing surface (30) ) of the chamber (3) and of the characteristic diameter (D ₂ ) of the sealing surface (20) of the shut-off body (2), ranges from 1 pm to a maximum of 5 pm, and as a pressure medium in the chamber (3) as well as in via terminals (A, B, P, T) at approx the trench (1) with said chamber (3) of the hydraulically interconnected lines is provided with plain water, optionally mixed with freezing agents at most. Valve according to claim 1, characterized in that said housing (1), at least in the area of its hydraulically sealing inner surface (30) of the chamber (3) with diameter (D ₃ ), consists of hardened martensitic stainless steel. Valve according to claim 2, characterized in that the martensitic stainless steel is selected from the group consisting of AISI 440B (DIN - X90CrMoV18) and AISI 440C (DIN - X105CrMol7) steels. Valve according to any one of claims 1-3, characterized in that the shut-off body (2), at least in the area of its outer hydraulic sealing surface (20) with diameter (D ₂ ), consists of hardened martensitic stainless steel. Valve according to claim 4, characterized in that the martensitic stainless steel is selected from the group consisting of AISI 440B (DIN - X90CrMoV18) and AISI 440C (DIN - X105CrMol7) steels. • · Valve according to one of Claims 1-5, characterized in that, in the case where the valve is intended for installation in a hydraulic circuit with a nominal pressure of the hydraulic medium between 50 and 150 bar, the clearance (C) between the surface (30) of the chamber (30) 3) and the area (20) of the closure organ (2) ranges from 1 pm to 4 pm. Valve according to one of Claims 1-5, characterized in that, in the case where the valve is intended for installation in a hydraulic circuit with a nominal pressure of the hydraulic medium between 150 and 250 bar, the clearance (C) between the surface (30) of the chamber (30) 3) and the area (20) of the closure organ (2) ranges from 1 pm to 3 pm. Valve according to one of Claims 1-5, characterized in that, when the valve is intended to be installed in a hydraulic circuit with a nominal pressure of hydraulic medium above 250 bar, the clearance (C) between the surface (30) of the chamber (3) and the area (20) of the closure organ (2) ranges from 1 pm to 2 pm. Valve according to any one of the preceding claims, characterized in that at least two solenoids (4 ', 4') are provided in the enclosure (1), which are electrically powered and operated in such a way that, after receiving a suitable signal, each a magnetic field, wherein the magnetic field of one of the electromagnets (4, 4 ') pushes the shut-off body (2) in the appropriate direction in each case, while at the same time the magnetic field of the rest of the electromagnets (4, 4') pulls the shut-off body (2) in the same direction direction. Valve according to claim 9, characterized in that the shut-off body (2) is supported on each side of the chamber by at least one pressure spring (5, 5 ') which is intended to generate force in the axial direction of the shut-off body (2). • · Valve according to any one of the preceding claims, characterized in that a filter for filtering the hydraulic medium is provided in the area of at least one of the ports (A, B, P, T) and preferably at the return line (T) of the return line. Valve according to claim 1, characterized in that the antifreeze agent selected from the group consisting of ethanol, ethylene glycol and propylene glycol is added to add water as the hydraulic medium.