Automatic two-way valve and pump equipped with the valve

Abstract

An automatic two-way valve for a high-pressure pump includes: a valve body; a central conduit having a first opening at a first end of the valve body and a second opening at a second end; a peripheral conduit having a first opening at a side surface of the valve body and a second opening at the second end; a first shielding member movable between a closed position and an open position, wherein the first opening of the central conduit is blocked in the closed position and the first opening of the central conduit is spaced apart from the first opening of the central conduit in the open position; a first elastic element for generating a force to maintain the first shielding member in the closed position; a second shielding member movable between a closed position and an open position, wherein the second opening of the peripheral conduit is blocked in the closed position and the second opening of the peripheral conduit is spaced apart from the second opening of the peripheral conduit in the open position; a second elastic element for generating a force to maintain the second shielding member in the closed position; and a retaining body fixed to the valve body, for maintaining the first elastic element or the second elastic element in an appropriate position so that the elastic element applies a force to the corresponding shielding member.

Description

Technical Field

[0001] The present invention relates to a valve, in particular an automatic two-way delivery and suction valve for a pump, for example a pump at high pressure, and a pump, preferably an axial piston pump, provided with such a valve. Background Art

[0002] Automatic two-way valves are known which, if connected to a pumping chamber, a delivery pipe and a suction pipe of a pump, automatically allow the liquid to be pumped to be drawn into the pumping chamber through the suction pipe based on the pressure difference and deliver the pumped fluid from the pumping chamber to the delivery pipe.

[0003] One known embodiment of an automatic two-way valve includes a valve body having a central conduit formed therein, the central conduit extending through the valve body from one side to the other, thereby defining a first opening at a first axial end of the valve body and a second opening at a second axial end of the valve body. The central conduit is configured to fluidically connect a pumping chamber to a delivery conduit.

[0004] The valve further comprises a peripheral conduit eccentric to the central conduit, the peripheral conduit being provided with a first opening formed in a side surface of the valve body and a second opening formed in a second end of the valve body. The peripheral conduit is configured to fluidically connect the suction conduit to the pumping chamber.

[0005] The valve further includes: a first shielding member for sealingly closing a first opening of the central pipe under the thrust of the first elastic element; and a second shielding member for sealingly closing a second opening of the peripheral pipe under the thrust of the second elastic element.

[0006] In particular, the valve is shaped so that when the volume of the pumping chamber increases, an underpressure is generated in the pumping chamber, which can overcome the force of the second elastic element, thereby releasing the second opening of the peripheral duct by the second shutter. Conversely, when the volume of the pumping chamber decreases, an overpressure is generated in the pumping chamber itself, which can overcome the force of the first elastic element, thereby releasing the first opening of the central duct by the first shutter.

[0007] A disadvantage of the prior art is that, in order to keep the elastic element in place, a suitable seat must be made and / or a suitable shoulder ring must be embedded in the pump head containing the pumping chamber, which leads to complexity both from the point of view of the design of the pump head and from the point of view of the assembly of the valve and / or the pump.

[0008] The object of the present invention is to overcome the limitations of the prior art within the context of a simple and rational construction solution.

[0009] This object is achieved by means of the features of the invention pointed out in the independent claim. The dependent claims outline preferred and / or particularly advantageous aspects of the invention. Summary of the invention

[0010] The present invention particularly provides an automatic two-way valve for a high-pressure pump, comprising:

[0011] - valve body;

[0012] a through-type central conduit which penetrates the valve body and is provided with a first opening formed in a first end of the valve body and a second opening formed in an opposite second end of the valve body;

[0013] a peripheral duct formed in the valve body, eccentrically with respect to the central duct and provided with a first opening formed in a portion of the valve body comprised between the first end and the second end and with a second opening formed in the second end of the valve body;

[0014] a first shield movable between at least a closed position, in which the first shield sealingly blocks the first opening of the central duct, and an open position, in which the first shield is spaced from the first opening of the central duct and allows the passage of fluid through the first opening itself;

[0015] - a first elastic element configured to generate a force suitable for maintaining said first shutter in its closed position;

[0016] a second shield movable between at least a closed position, in which the second shield sealingly blocks the second opening of the peripheral duct, and an open position, in which the second shield is spaced from the second opening of the peripheral duct and allows the passage of fluid through the second opening itself;

[0017] - a second elastic element configured to generate a force suitable for maintaining the second shutter in its closed position; and

[0018] - a retaining body fixed to the valve body and configured to retain one of the first elastic element and the second elastic element in position so that the elastic element exerts the force on the corresponding shutter.

[0019] Thanks to this solution, no machining is required to form in the head of the pump which must house the valve a shoulder suitable for holding the elastic element in position relative to the valve body, which allows to reduce design and production times and costs. Furthermore, since the retaining body is fixed relative to the valve body, the assembly operations of the pump are simplified and accelerated.

[0020] According to one aspect of the invention, the retaining body may be removably fixed to the valve body.

[0021] This feature can make maintenance operations of the valve easier, for example allowing replacement of the elastic element.

[0022] For example, the retaining body may be fixed to the valve body by a snap-fit ​​coupling mechanism.

[0023] In this way, assembly and disassembly of the valve is particularly practical and rapid and does not require the use of tools.

[0024] According to another aspect of the present invention, the retaining body may be configured to retain the second elastic element in place.

[0025] Typically, as shown herein, the second end is the end that faces the pumping chamber so that no shoulder is required in the cylinder or the cylinder's bushing (if a bushing is provided) to hold the retaining body in place.

[0026] According to another aspect of the present invention, the valve may include two retaining bodies, a first retaining body and a second retaining body, wherein the first retaining body is fixed to the valve body and is configured to hold the first elastic element in an appropriate position, and the second retaining body is fixed to the valve body and is configured to hold the second elastic body in an appropriate position.

[0027] Another aspect of the present invention provides that the second retaining body may include a cup-shaped portion, which is provided with a through hole and a through opening, wherein the through hole is at least partially aligned with the central hole of the valve body, the through opening is eccentric relative to the through hole, and is suitable for being closed by the second shielding member when the fluid from the peripheral pipeline overcomes the force of the second elastic element at the outlet.

[0028] In this way, a faster closing of the second shutter is ensured when the pressure in the pumping chamber of the pump in which the valve is installed increases. In addition, this feature allows a faster opening of the second shutter, because it allows the fluid present in the retaining body to be discharged faster. These are advantages compared to when there is only a through hole in the retaining body.

[0029] Another aspect of the present invention provides that the valve body may be integral and made of a single material.

[0030] In this way, the valve is particularly resistant and durable.

[0031] Furthermore, the single material of which the valve body is made may be a metal material selected from the group consisting of stainless steel, brass alloys, and aluminum alloys.

[0032] In particular, aluminum should therefore be surface hardened.

[0033] These features help improve resistance and increase the life of the valve.

[0034] The present invention also provides an axial piston pump for pumping liquid, comprising:

[0035] - base;

[0036] - a head, which is fixed to the base;

[0037] - a plurality of cylinders having central axes parallel to one another and formed in the head;

[0038] - a plurality of pistons, each of the pistons sliding in a corresponding cylinder of the plurality of cylinders to pump a liquid;

[0039] - a tilting piston configured to drive said piston to slide within said corresponding cylinder; and

[0040] - A valve according to at least one of the above aspects of the invention for each of said cylinders.

[0041] Thanks to this solution, a pump is provided which is of quicker design than prior art devices and which can be assembled more quickly.

[0042] According to one aspect of the invention, each cylinder may be formed in the head like a blind hole and each valve may be housed in the bottom of the corresponding cylinder, the bottom being shaped so that the valve is oriented so that the central axis of the central conduit is parallel to the central axis of the cylinder and blocks the bottom.

[0043] Thanks to this solution, the head is more resistant to fatigue loads due to pressure pulsations and can therefore be made of a material that is less resistant to fatigue loads than materials currently used, such as stainless steel and brass, such as aluminum. Aluminum has the advantage of being easier to process and lighter than stainless steel and brass alloys. The advantage is particularly reflected in that, relative to the pumps of the prior art, this construction allows reducing the number of holes that pass through the head for the insertion of the valves and thus reducing the geometry of the head that causes the notch effect and thus reduces the fatigue resistance of the head. In particular, in the known axial piston pumps with inclined pistons, each cylinder uses a one-way automatic suction valve and a one-way automatic delivery valve, and in order to install at least one of these two valves, a hole must be made in the surface of the head opposite to the base. The construction of the pump according to the invention makes it unnecessary to make these holes at these locations, thereby improving the fatigue resistance of the head.

[0044] Furthermore, the valve essentially acts as a shield for the bottom wall against fatigue pressure changes occurring in the pumping chamber.

[0045] Furthermore, this configuration allows all pump connection components for suction and delivery to be formed on only one side.

[0046] Another aspect of the invention contributes to completing these improvements in fatigue stress resistance, according to which each cylinder comprises a bushing inserted in the cylinder itself, in which the corresponding piston slides, and which bushing extends from the automatic two-way valve to at least one first annular sealing gasket surrounding the piston.

[0047] In this way, since the valve and the bushing substantially isolate the head from said pulsations, fatigue stresses to which the head is subjected can be further reduced.

[0048] According to another aspect of the present invention, the head is made of die-cast aluminum.

[0049] In this way, the head is light and easy to process. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Other characteristics and advantages of the invention will become more apparent on reading the following description, given by way of non-limiting example, with the help of the figures shown in the accompanying drawings.

[0051] Figure 1 is a front view of an automatic two-way valve according to the present invention.

[0052] Figure 2 The edge is shown in the suction stage Figure 1 Cross-sectional view of the valve in plane II-II.

[0053] Figure 3 It is shown along the conveying stage. Figure 1 Cross-sectional view of the valve in plane II-II.

[0054] Figure 4 is a top view of a pump provided with a valve according to the invention.

[0055] Figure 5 yes Figure 4 A cross-section of the pump along plane VV.

[0056] Figure 6 yes Figure 4 Sectional view of the pump along plane VI-VI.

[0057] Figure 7 is a cross-sectional view of an alternative embodiment of a valve according to the present invention.

[0058] Figure 8 According to the present invention, there is Figure 7 A cross-sectional view of an axial piston pump showing an embodiment of the valve is shown. DETAILED DESCRIPTION

[0059] Special reference Figures 1 to 3 , reference numeral 1 generally represents an automatic two-way valve, hereinafter referred to as valve 1.

[0060] It should be noted that an automatic valve refers to a valve that is configured to automatically open once a preset difference between the pressures existing in the environments separated by the valve itself is reached, thereby allowing fluid communication between two or more environments (between which the valve is placed). In more detail, an automatic valve does not utilize an electromechanical actuation mechanism, but only a pressure difference.

[0061] It should also be noted that a two-way valve refers to a valve that is suitable for being placed between a first environment, a second environment, and a third environment and is configured to selectively connect only the first environment to the second environment or only the second environment to the third environment. When the valve is installed in a pump, the first environment is a suction pipe, the second environment is a pumping chamber, and the third environment is a delivery pipe.

[0062] Described below Figures 1 to 6 The first embodiment of the valve 1 is shown in FIG. The valve 1 comprises a valve body 5 which is penetrated from one side to the other by a central duct 10 having a first opening 15 and an opposite second opening 20 formed in the valve body itself. That is, the central duct 10 comprises a first opening 15 formed in a first end 25A of the valve body 5 and a second opening 20 formed in an opposite second end 25B of the valve body 5. In particular, the central duct 10 has only the first opening 15 and the second opening 20.

[0063] These ends are the axial ends of the valve body 5 relative to the central axis Z of the valve body itself, with which the central duct 10 is coaxial. In particular, the valve body 5 is shaped like a body of revolution relative to said central axis Z.

[0064] In addition, the valve body 5 may include a first part 30, a second part 35 and a third part 40, the first opening 15 is formed in the first part 30, the second opening 20 is formed in the second part 35, and the third part 40 is inserted between the first part and the second part (for example, directly and in contact) and penetrated by the central pipe 10.

[0065] The first portion 30 is cylindrical and coaxial with the central axis Z, in particular it has a cylindrical lateral surface 30 a. It comprises, for example, a seat 45 shaped like an annular recess formed in the cylindrical lateral surface of the first portion itself, suitable for housing a sealing gasket 50 .

[0066] The second portion 35 is also cylindrical and coaxial with the central axis Z, in particular it has a cylindrical lateral surface 35 a. The second portion 35 comprises, for example, a seat 55 shaped like an annular recess formed in the cylindrical lateral surface of the second portion itself, suitable for housing a sealing gasket 60 .

[0067] The third portion 40 is cylindrical and has a larger radius than the first portion and the second portion, thereby protruding relative to the first portion and the second portion in a radial direction relative to the central axis Z. In particular, the third portion has a cylindrical side surface 40a protruding radially relative to the cylindrical side surface 30a of the first portion and the cylindrical side surface 35a of the second portion.

[0068] The valve body 5 comprises a first abutment surface 65 and an opposite second abutment surface 70 transverse to the central axis Z. In particular, the abutment surfaces 65, 70 are flat (eg annular), preferably lying transversely on a plane perpendicular to the central axis Z.

[0069] The first abutment surface 65 and the second abutment surface 70 may be formed in the third portion 40 of the valve body 5. In practice, the abutment surfaces 65, 70 protrude radially in a cantilevered manner relative to the first portion 30 and the second portion 35 (i.e. relative to the cylindrical side surface 30a of the first portion and the cylindrical side surface 35a of the second portion) in opposite directions relative to the central pipe 10. Purely as an example, the first abutment surface 65 is oriented toward the first portion 30, while the second abutment surface 70 is oriented toward the second portion 35. In this case, the first abutment surface 65 extends from the cylindrical side surface 40a of the third portion 40 to the cylindrical side surface 30a of the first portion, and the second abutment surface 70 extends from the cylindrical side surface 40a of the third portion 40 to the cylindrical side surface of the second portion 35.

[0070] The first 65 and second 70 abutment surfaces are adapted to allow correct positioning and locking of the valve body 5 when the valve body 5 is inserted into a corresponding seat formed in the pump.

[0071] The central conduit 10 penetrating the valve body is linear and preferably provided with a cylindrical inner surface, and the central conduit 10 sequentially penetrates the first portion 30 , the third portion 40 and the second portion 35 .

[0072] The valve body 5 is made as a single integral body of a single metallic material, ie it is obtained by machining a single body obtained by solidifying a single casting or injection of the material into a mold.

[0073] The metal material is selected from the group consisting of stainless steel, brass alloy and aluminum alloy.

[0074] In the case of aluminum, it must subsequently be hardened on the surface.

[0075] The valve 1 comprises a peripheral duct 75 formed in the valve body (eg in the second portion 35 and in the third portion 40 ) and eccentric and distinct from the central duct 10 .

[0076] The peripheral duct 75 comprises a first opening 80 formed in a portion, such as a side surface, of the valve body 5 comprised between the first end 25A and the second end 25B. For example, the first opening is formed in the cylindrical side surface 40a of the third portion 40. Specifically, the first opening 80 leads to an annular groove 85 formed in the third portion and opened on the cylindrical side surface 40a of the third portion itself.

[0077] The peripheral duct 75 further comprises a second opening 90 . In particular, the peripheral duct only has the first opening 80 and the second opening 90 .

[0078] The second opening 90 is formed at the second end of the valve body 5 and is different from the second opening 20 of the central pipe 10. Preferably, the second opening 20 of the central pipe and the second opening 90 of the peripheral pipe 75 are located on the same plane (e.g., a plane perpendicular to the central axis Z). That is, the second end of the valve body includes a flat surface (e.g., perpendicular to the central axis Z) in which the second opening 90 of the peripheral pipe 75 is formed.

[0079] For example, the peripheral duct 75 comprises at least a straight segment terminating in the second opening 90 and having a longitudinal axis parallel to the central axis Z.

[0080] Preferably, the valve comprises a plurality of peripheral ducts 75 , each of which has a shape as described above and which is arranged circumferentially relative to the central duct 10 , ie relative to the central axis Z.

[0081] The valve 1 comprises a first shielding member 95 which is movable between at least a closed position, in which the first shielding member 95 sealingly blocks the first opening 15 of the central conduit 10, and an open position, in which the first shielding member 95 is spaced from the first opening 15 of the central conduit and allows fluid to pass through the first opening itself.

[0082] In particular, the first shield comprises a contact surface 100 which, when the first shield is in the closed position, contacts at least along the closed periphery a seat 105 of the first shield formed at the first opening 15 in the valve body 5. For example, the first shield 95 is provided with a frustoconical contact surface 100 and the seat 105 is provided with a matching frustoconical contact surface.

[0083] The valve 1 further comprises a second shielding member 110 which is movable between at least a closed position and an open position, wherein in the closed position the second shielding member 110 sealingly blocks the second opening 90 of the peripheral conduit 75, and in the open position the second shielding member 110 is spaced from the second opening 90 of the peripheral conduit 75 and allows fluid to pass through the second opening itself.

[0084] In particular, the second shield 110 includes a contact surface 115, which, when the second shield is in the closed position, contacts at least along the closed periphery with a seat 120 of the second shield formed at the second opening 90 in the valve body 5. For example, the contact surface 115 is flat, and the seat 120 is provided with a matching flat contact surface. In particular, the flat contact surface of the second shield is annular and is shaped to contact with a flat surface to which the second openings 90 of the plurality of peripheral conduits 75 lead.

[0085] The second shielding member 110 comprises a through hole 125 which is always in direct fluid communication with the central duct through the second opening 20. In particular, the through hole 125 passes through the contact surface 115 of the second shielding member itself.

[0086] For example, the through hole 125 is coaxial with the central axis Z and is located inside with respect to the flat contact surface 115 of the second shielding member 110 .

[0087] Furthermore, the through hole 125 may have a diameter greater than a diameter of the second opening 20 of the central pipe 10 .

[0088] The valve 1 comprises a first elastic element 130 configured to generate a force suitable for keeping the first shield 95 in the closed position and a second elastic element 135 configured to generate a force suitable for keeping the second shield 110 in the closed position. These elastic elements are preferably springs, such as helical compression springs.

[0089] In addition, the valve 1 includes a retaining body 140, 145, which is, for example, rigidly (i.e., without any remaining degrees of freedom) fixed to the valve body 5 and is configured to hold one of the first elastic element and the second elastic element in an appropriate position relative to the valve body 5 so that the elastic element generates a force suitable for holding the corresponding cover in the closed position.

[0090] In particular, the retaining bodies 140 , 145 are removably fixed to the valve body 5 , ie, the retaining bodies 140 , 145 are fixed to the valve body by a connection piece which allows both fixing the retaining bodies 140 , 145 to the valve body and removing the retaining bodies 140 , 145 from the valve body.

[0091] In particular, the retaining body 140 , 145 is fixed to the valve body by a snap-fit ​​coupling mechanism, ie the connection comprises a snap-fit ​​coupling mechanism.

[0092] The snap-fit ​​coupling mechanism is of a type in which, during the mutual approach of the valve body and the retaining body 140, 145, at least one of the valve body and the retaining body 140, 145 is elastically deformed relative to the other, so that during the approach, the protrusion of one slides on the contact surface of the other until it is inserted into the cavity of the other and then is retained in the cavity due to the elastic deformation generated during the relative sliding. The cavity is shaped to prevent the retaining body 140, 145 from moving in a direction parallel to the central axis Z by an obstruction. For example, the retaining body 140, 145 is elastically deformed relative to the valve body.

[0093] In particular, the retaining body 140, 145 may include at least one end provided with a protrusion and a flexibly deformable wall, the protrusion protruding from the wall toward the center of the retaining body 140, 145 itself. The valve body includes a cavity (e.g., an annular groove) suitable for accommodating the retaining body 140, 145 and shaped to prevent the retaining body 140, 145 from moving in a direction parallel to the central axis Z by an obstruction.

[0094] The holding bodies 140 , 145 have a portion shaped like a cup, in which the corresponding shield is accommodated.

[0095] For example, the retaining body 140, 145 comprises an abutment surface for the shutter, which is spaced from the valve body 5 and preferably perpendicular to the central axis Z, and which defines the end point of the movement of the shutter away from the valve body. In particular, the abutment surface defines the maximum open position of the shutter itself, in which the distance between the shutter and the corresponding opening configured to be closed by the shutter is the largest.

[0096] The abutment surface contacts a surface of the corresponding shielding member, which is opposite to the contact surface of the corresponding shielding member.

[0097] It is not excluded that in alternative embodiments, the retaining bodies 140 , 145 are fixed to the valve body by other removable connection means, such as threaded connections or threads formed on the retaining bodies 140 , 145 and on the valve body itself.

[0098] Furthermore, the retaining body comprises a surface adapted to act as a guide for the respective shutter, thereby preventing the shutter from rotating relative to an axis of rotation perpendicular to the direction in which the shutter itself moves.

[0099] The valve may include a first retaining body 140 and a second retaining body 145 .

[0100] The first retaining body 140 is fixed to the valve body 5, in particular to the first part 30 (for example, rigidly, i.e., without any residual degrees of freedom), and is configured to hold the first elastic element 130 in an appropriate position relative to the valve body 5 so that the first elastic element 130 generates a force suitable for keeping the first cover member 95 in a closed position.

[0101] The first retaining body 140 may be removably fixed to the valve body, ie fixed to the valve body by a connection piece which allows both fixing the first retaining body 140 to the valve body 5 and removing the first retaining body from the valve body 5 .

[0102] For example, the first retaining body 140 is fixed to the valve body by means of a snap-fit ​​coupling mechanism 150 , ie the connection member comprises a snap-fit ​​coupling mechanism.

[0103] In particular, the first retaining body 140 comprises a cup-shaped portion, arranged with a recess facing the valve body 5 (i.e., facing the first part 30 of the valve body), and the snap-fit ​​connection mechanism 150 comprises a flexibly deformable end formed at one end of the cup-shaped body facing the valve body, the end being provided with a protrusion 155, which is, for example, annular and concentric with the central pipe 10, and which protrudes toward the internal volume of the cup-shaped portion. The snap-fit ​​connection mechanism of the first retaining body 140 also comprises a cavity (e.g., an annular groove 160), which is formed in the valve body (i.e., in the first part of the valve body) and is suitable for accommodating the protrusion of the first retaining body. The cavity is shaped so as to achieve connection with the protrusion through the obstruction.

[0104] The first retaining body may include an abutment surface 165 for the first shutter 95. The abutment surface 165 is spaced from the valve body 5 and is preferably perpendicular to the central axis Z and defines a stop point for the first shutter 95 when it moves away from the valve body.

[0105] Furthermore, the first retaining body may include a through hole 125 formed at a bottom wall of the cup opposite to a portion of the first retaining body contacting the valve body 5. The fluid flow passing through the first opening 15 of the central pipe 10 passes through the through hole 125.

[0106] The second retaining body 145 is fixed to the valve body 5, in particular to the second part 35 (for example, rigidly, i.e., without any residual freedom), and is configured to hold the second elastic element 135 in an appropriate position relative to the valve body 5, so that the second elastic element 135 generates a force suitable for keeping the second cover 110 in the closed position.

[0107] The second retaining body 145 may be removably fixed to the valve body 5 , ie fixed to the valve body 5 by a connecting piece which allows both fixing the second retaining body 145 to the valve body 5 and removing the second retaining body 145 from the valve body 5 .

[0108] For example, the second retaining body 145 is fixed to the valve body by means of a snap-fit ​​coupling mechanism 175 , ie the connection comprises a snap-fit ​​coupling mechanism.

[0109] In particular, the second retaining body 145 comprises a cup-shaped portion, arranged with a recess facing the valve body 5 (i.e., facing the second part 35), and the snap-fit ​​connection mechanism 175 comprises a flexibly deformable end formed at one end of the cup-shaped body facing the valve body, the end being provided with a protrusion 180, which is, for example, annular and concentric with the central pipe 10, and which protrudes toward the inner volume of the cup-shaped portion. The snap-fit ​​connection mechanism of the second retaining body 145 also comprises a cavity (e.g., an annular groove 185 concentric with the central pipe 10), which is formed in the valve body 5 (i.e., in the second part 35) and is suitable for accommodating the protrusion 180 of the second retaining body, the cavity being shaped to form a connection with the protrusion through an obstruction.

[0110] The second retaining body 145 may include an abutment surface 190 for the second shield 110. The abutment surface 190 is spaced from the valve body 5 and is preferably perpendicular to the central axis Z, and defines a stop point when the second shield 110 moves away from the valve body.

[0111] The abutment surface 190 is in contact with a surface of the second shield, which faces in a direction opposite to the surface of the second shield itself that is in contact with the seat.

[0112] The second retaining body 145 may include a through hole 195 formed at the bottom wall of the cup-shaped portion, which is opposite to the portion of the second retaining body that contacts the valve body 5. The through hole 195 is directly and always in fluid communication with the through hole 125 of the second shielding member, and in particular, the through hole 195 is also coaxial with the central axis Z. In particular, at least a portion of the fluid flow passing through the second opening 20 of the central pipe 10 passes through the through hole 195.

[0113] The second retaining body 145 may further include at least one through opening 200 formed in the cup-shaped portion and configured such that the second shield 110 only partially blocks the through opening when the second shield is in contact with the abutment surface 190 (ie, in the maximum open position).

[0114] From a fluid dynamics point of view, the through opening 200 is parallel to the through hole 195 relative to the second opening 20 of the central pipe 10 .

[0115] The through opening 200 is eccentric relative to the through hole 195 and, for example, is located radially further outward than the abutment surface 190 of the second shield (relative to the center axis Z). In particular, the second shield 110 protrudes radially relative to the abutment surface 190 of the second holding body (in a direction moving away from the center axis Z), and the through opening 200 is at least partially aligned with the protruding portion in a direction parallel to the center axis Z.

[0116] Thanks to the orifice 200 , the second shutter 110 can be brought into the closed position more quickly when the pressure at the second opening 90 of the peripheral duct is lower than the pressure measured at a point situated outside the cup of the second retaining body 145 .

[0117] Preferably, the second holding body 145 includes a plurality of through openings 200 which are arranged circumferentially around the through hole 195 .

[0118] In the embodiment shown, the first and second retaining bodies are cup-shaped, ie the cup-shaped portion discussed above substantially constitutes the retaining body itself. However, it is not excluded that in embodiments not shown, the retaining body may be formed as a folded rod or sheet.

[0119] Special reference Figure 4 and Figure 5 , reference numeral 205 denotes an axial piston pump for high pressure, which is provided with at least one valve 1 for adjusting the pumping flow. In particular, reference numeral 205 is an axial piston pump for high pressure, and is an axial piston pump of a rotary piston type inclined at a fixed inclination.

[0120] The axial piston pump 205 may include a base 210 , a rotating disk 215 , and, for example, a flange 220 . The rotating disk 215 is adapted to receive the rotational movement of a motor shaft from outside the axial piston pump 205 , and the flange 220 is used for fixing with a motor provided with the motor shaft.

[0121] The rotating disk 215 is accommodated in the base 210 and is rotatably associated with the base 210 relative to the rotation axis A. For example, the rotating disk 215 includes a flat annular surface that lies on a plane inclined relative to the rotation axis A.

[0122] The axial piston pump 205 includes a head 225, which is fixed to the base 210, that is, fixed to the base 210 without any remaining freedom, and a plurality of cylinders 230 (i.e., cylindrical holes) are formed in the head 225, each cylinder 230 is suitable for accommodating a corresponding liquid pumping chamber 235 and is arranged with respective central axes parallel to each other.

[0123] These center axes are also preferably parallel to the axis of rotation A.

[0124] The head 225 may be made as a single integral body, obtained by machining a single body obtained by solidifying a single casting or injection of material into a mold.

[0125] For example, the plurality of cylinders 230 are radially arranged along a common axis, and their central axes are parallel to the common axis. In addition, the plurality of cylinders 230 are equidistant from each other, and the plurality of cylinders 230 are equidistant from the common axis. In other words, the plurality of cylinders 230 (i.e., the central axes of the plurality of cylinders 230) are angularly arranged equidistant from each other along an imaginary circle centered on the common axis. For example, the common axis of the plurality of cylinders 230 is the rotation axis A.

[0126] Preferably, the cylinder 230 is made into a blind hole, and each cylinder 230 has an opening 240 facing the base. In particular, the head may include a first face 245 and an opposite second face 250. The first face 245 is transverse to the central axis of the cylinder and close to the base 210, preferably in contact with the base 210, and the first face 245 is, for example, flat. The second face 250 is transverse to the central axis of the cylinder and away from the base 210. The cylinder 230 (i.e., the cylindrical hole) only passes through the first face 245, so that the corresponding opening 240 is formed in the first face 245. In practice, the second face 250 is continuous, i.e., without interruption. That is, relative to the axial piston pump of the prior art, the axial piston pump of the present application does not have a hole passing through the second face 250.

[0127] It should be noted that the second face 250 and the first face 245 are connected by a tubular side surface 255 of the head.

[0128] Each cylinder comprises a bottom opposite to the corresponding opening 240 and comprises a bottom wall 260 lying on a plane transverse to (eg perpendicular to) the axis of the cylinder itself. For example, the bottom wall 260 is spaced a non-zero distance from the second face of the head.

[0129] The valve 1 is accommodated at the bottom, which is shaped so that the valve 1 is arranged with the second opening 20 of the central duct 10 facing the opening of the cylinder.

[0130] The valve 1 is completely accommodated in the bottom.

[0131] In detail, the bottom comprises a first cylindrical surface 265, for example coaxial with the axis of the cylinder 230, which extends from the bottom surface 260 in the direction of the opening 240 of the cylinder 230, into which a portion of the valve body (in particular the first portion 30) is inserted with appropriate dimensions. In practice, the first cylindrical surface 265 has a diameter greater than the diameter of the cylindrical side surface 30a of the first portion 30 of the valve body 5.

[0132] The first retaining body 140 is completely contained within the volume partially defined by the first cylindrical surface 265 and the bottom wall 260 .

[0133] The extension of the first cylindrical surface 265 in the axial direction of the cylinder 230 is at least equal to the distance measured in the same direction between the first abutment surface 65 of the valve body 5 and the surface of the first retaining body 140 farthest from the first abutment surface 65 .

[0134] The diameter of the entire extension of the first cylindrical surface 265 in the direction of the central axis of the cylinder is always greater than the maximum overall dimension of the first holding body 140 in a direction perpendicular to the central axis of the cylinder. That is, the first cylindrical surface 265 is shaped so that there is an annular gap of non-zero size between itself and the first holding body 140 along the entire extension of the first cylindrical surface itself.

[0135] In other words, the bottom does not include any surface that contacts the first retaining body 140 to keep the first retaining body 140 in contact with the valve body 5, that is, the bottom does not include any shoulder for holding the first retaining body 140 in a certain position.

[0136] The sealing gasket 50 housed in the seat 45 formed in the first portion 30 is then pressed between its seat and the first cylindrical surface 265 .

[0137] The bottom also comprises a second cylindrical surface 270 which develops in the direction of the opening 240 and is directly connected to the first cylindrical surface 265 via a step 275, against which the first abutment surface of the valve 1 abuts. The second cylindrical surface 270 has a diameter which is appropriately sized to accommodate the third portion 40, i.e. the diameter of the second cylindrical surface 270 is substantially equal to the diameter of the cylindrical side surface 40a of the third portion 40 of the valve body.

[0138] The cylinder comprises an inlet portion extending from the bottom to the opening 240 and comprises a third cylindrical surface 280 extending in the direction of the opening 240 and directly connected to the second cylindrical surface 270 via a further step 285. The third cylindrical surface 280 has a larger diameter than the second cylindrical surface 270.

[0139] The axial piston pump 205 also includes a cylindrical tubular sleeve 290, each cylinder 230 is inserted with the sleeve 290, and an annular abutment surface 295 is provided at one of the axial ends of the sleeve 290, the annular abutment surface is transversely arranged on a plane transverse to the center axis Z (for example, perpendicular to the center axis Z) and contacts the second abutment surface 70 of the valve 1.

[0140] The base and bushing are shaped in such a way that when the head 225 is fixed to the base 210 , the bushing 290 pushes the second abutment surface 70 of the valve body 5 to keep the first abutment surface 65 of the valve body in contact with the step 275 , substantially by retaining the valve 1 in the seat.

[0141] For example, between the axial end of the bushing 290 (the axial end opposite to the axial end contacting the valve 1) and the base, there is at least one sleeve suitable for accommodating the sealing gasket 300 and, when the head is fixed to the base, the sleeve is pressed between the bushing and the base itself.

[0142] The bushing includes an inner surface 305 having a diameter at the annular abutment surface 295 to accommodate the second portion 35 of the valve body with appropriate dimensions (i.e., with reduced clearance). That is, at the annular abutment surface 295, the smallest diameter of the inner surface of the bushing is greater than the diameter of the cylindrical side surface 35a of the second portion 35 of the valve body 5.

[0143] The sealing gasket 60 housed in the seat 55 formed in the second portion 35 is then pressed between its seat and said inner surface 305 .

[0144] There is always a non-zero size gap between the inner surface 305 of the bushing and the second retaining body 145 .

[0145] Furthermore, the profile of the inner surface 305 defined by the section containing the central axis of the cylinder forms, in each of its sections, an acute angle of less than 30° with an axis parallel to the central axis Z and intersecting the profile itself.

[0146] In other words, the bushing does not include any surface that contacts the second retaining body 145 so as to keep the second retaining body 145 in contact with the valve body 5 or that keeps the diaphragm in contact with the second retaining body 145 so as to press the second retaining body 145 against the valve body 5, that is, the bushing does not include any shoulder for holding the second retaining body in a certain position.

[0147] In the embodiment shown, the inner surface 305 of the bushing comprises a cylindrical first section, a frustoconical second section and a cylindrical third section. The first section is sized to accommodate the second portion of the valve body. The second section is directly adjacent to the first section, and the profile of the second section defined by a cross section containing the central axis of the cylinder forms an acute angle of less than 20° with an axis parallel to the central axis and intersecting the profile itself. The third section is directly adjacent to the second section and has a smaller diameter than the first section.

[0148] The bushing may be made of aluminum, steel or brass, preferably aluminum.

[0149] The axial piston pump 205 includes a plurality of pistons 310, each piston 310 being adapted to slide in a corresponding cylinder 230 (i.e., in a corresponding cylinder liner 290) under the drive of a rotating disk 215 to pump a fluid present in a corresponding pumping chamber 235, wherein the pumping chamber 235 is at least partially defined by the cylinder (i.e., by the cylinder liner) and the valve 1.

[0150] In particular, the volume of the pumping chamber 235 is at least partially defined by the piston 310 , the cylinder (ie, the cylinder liner), the valve body, the central conduit 10 , and the first shielding member 95 .

[0151] As the rotating disk 215 rotates, the piston 310 slides along the central axis of the corresponding cylinder 230 between the top dead center position and the bottom dead center position. At the top dead center position, the volume of the pumping chamber 235 is the smallest, and at the bottom dead center position, the volume of the pumping chamber is the largest.

[0152] In the illustrated embodiment, each piston 310 has a first axial end and an opposite second axial end, wherein the first axial end partially defines a pumping chamber and the second axial end extends from the cylinder into the base 210 and is maintained in contact with an annular guide 325 through a corresponding elastic element 320, and the annular guide 325 rests on the flat annular surface of the rotating disk 215.

[0153] Each elastic element 320 has a first end and a second end, the first end being connected to the base 210 and the second end being connected to the piston 310 (eg, near the second end).

[0154] The axial piston pump 205 includes a plurality of annular sealing rings adapted to sealingly surround the corresponding piston 310, for example, some of the annular gaskets are housed in the base 210, while some of the annular gaskets are housed in the head 20 (particularly in the cylinder liner) to prevent fluid communication between the pumping chamber 235 and the base 210.

[0155] Furthermore, the axial piston pump 205 may include a plurality of guide sleeves 326 formed, for example, in the base 210 , each guide sleeve 326 being adapted to guide a corresponding piston 310 to slide along a central axis of a corresponding cylinder 230 .

[0156] These guide bushings 326 communicate with openings 240 of corresponding cylinders formed in the head 225 .

[0157] The axial piston pump 205 may include a plurality of fastening screws configured to secure the head to the base, the plurality of fastening screws being inserted into the same number of through holes formed in the head.

[0158] The pump comprises at least one suction duct 330 for the cylinder, comprising a hole formed in the head 225 and provided with openings 335 formed in the lateral surface 255 of the head.

[0159] The suction duct also comprises at least one outlet opening 340 , one per cylinder, formed in the bottom of the cylinder, in particular at the second cylindrical surface 270 .

[0160] The longitudinal axis of the hole of the suction duct is inclined at an angle of less than 2° relative to a plane perpendicular to the central axis of the cylinder. In the embodiment shown, the longitudinal axis of the suction duct (i.e. the longitudinal axis of the corresponding hole formed in the head) is perpendicular to the axis of the cylinder.

[0161] The pump includes a suction manifold leading to a suction conduit 330 .

[0162] The pump 1 comprises a plurality of delivery ducts 350, each delivery duct 350 comprising a hole formed in the head 225 and provided with an outlet opening 355 formed in the side surface 255 of the head. Each delivery duct 350 comprises a plug 360 sealingly closing the respective outlet opening.

[0163] Each delivery duct 350 comprises an inlet opening 365 for each cylinder 230 , which inlet opening 365 is formed in the bottom of the cylinder, in particular in the first cylindrical surface 265 .

[0164] The longitudinal axis of each hole of each delivery conduit is inclined at an angle of less than 2° relative to a plane perpendicular to the central axis of the cylinder. In the embodiment shown, the longitudinal axis of the hole in the delivery conduit is perpendicular to the axis of the cylinder.

[0165] The pump further comprises a delivery manifold 370 adapted to merge with all the delivery ducts 350, the delivery manifold 370 being formed in the head and comprising holes formed in the head 225, the delivery manifold 370 being provided with outlet openings formed in the side surface of the head.

[0166] The longitudinal axis of the bore in the delivery manifold is inclined at an angle of less than 2° relative to a plane perpendicular to the central axis of the cylinder. In the embodiment shown, the longitudinal axis of the bore of the delivery manifold is perpendicular to the axis of the cylinder.

[0167] The head is preferably made of aluminium.

[0168] In particular, the head can be made of aluminium, as the cylinder liner and valve are shaped and positioned so as to isolate the pumping chamber from the cylinder and thus the head from pressure pulsations which cause problems in terms of fatigue wear.

[0169] The operation of the valve and the pump provided with the valve is as follows.

[0170] When the pump performs the suction phase, i.e., when the piston descends toward the bottom dead center, low pressure is generated in the pumping chamber, whereby the first elastic element 130 keeps the first shielding member in the closed position, thereby isolating the pumping chamber 235 from the delivery pipeline, and the fluid present in the suction pipeline can overcome the force of the second elastic element 135, thereby placing the second shielding member 110 in the open position. This allows the fluid from the delivery pipeline to flow into the pumping chamber.

[0171] When the piston rises from the bottom dead center toward the top dead center, the pump performs a pumping phase, during which the increase in pressure in the pumping chamber causes the second elastic element 135 to place the second baffle in the closed phase, and the pressurized fluid passing through the central channel pushes the first baffle 95 to overcome the force of the first elastic element 130 to place the first baffle in the open position and deliver the fluid to the delivery pipeline.

[0172] Special reference Figure 7 and 8 , respectively show an alternative embodiment of a valve 1 ′ and an alternative embodiment of an axial piston pump 205 ′ with a rotary piston in which the valve 1 ′ is installed.

[0173] The valve 1 ′ differs from the valve 1 substantially in that a first opening 80 ′ of the peripheral duct 75 ′ is formed in the first abutment surface 65 ′, in this case towards the first opening 15 of the central duct 10 , and an annular groove 85 ′ is formed in the first portion 30 ′ instead of the third portion 45 ′.

[0174] For example, in this embodiment, the peripheral duct 75 ′ has only rectilinear holes parallel to the axis Z.

[0175] Furthermore, the annular groove 85 ′ is directly adjacent to the first abutment surface 65 ′.

[0176] The invention thus conceived is susceptible of numerous modifications and variations, all of which are within the scope of the inventive concept.

[0177] Moreover, all the details may be replaced by other technically equivalent elements.

[0178] In practice, the materials used, as well as the possible shapes and dimensions, may be any according to requirements without thereby departing from the scope of protection of the appended claims.

Claims

1. An automatic two-way valve for a high-pressure pump, comprising: - valve body (5); - a through-type central conduit (10) which penetrates the valve body (5) and is provided with a first opening (15) formed in a first end (25A) of the valve body (5) and a second opening (20) formed in an opposite second end (25B) of the valve body (5); - a peripheral duct formed in the valve body (5), eccentrically relative to the central duct (10), and provided with a third opening formed in a portion of the valve body (5) included between the first end (25A) and the second end (25B) and a fourth opening (90) formed in the second end (25B) of the valve body (5); - a first shield (95) movable between at least a closed position, in which the first shield (95) sealingly blocks the first opening (15) of the central duct (10), and an open position, in which the first shield (95) is spaced from the first opening (15) of the central duct (10) and allows the passage of fluid through the first opening itself; - a first elastic element (130) configured to generate a force suitable for maintaining the first shutter (95) in its closed position; - a second shield (110) movable between at least a closed position, in which the second shield (110) sealingly blocks the fourth opening (90) of the peripheral duct (75), and an open position, in which the second shield (110) is spaced from the fourth opening (90) of the peripheral duct (75) and allows fluid to pass through the fourth opening itself; - a second elastic element (135) configured to generate a force suitable for maintaining the second shield (110) in its closed position; as well as - a retaining body, which is removably fixed to the valve body (5) and is configured to retain one of the first elastic element (130) and the second elastic element (135) in an appropriate position so that the first elastic element (130) or the second elastic element (135) applies the force to the corresponding first shielding member (95) or the second shielding member (110), wherein the retaining body is fixed to the valve body by a snap-fit ​​connection mechanism, wherein during the process of the valve body and the retaining body approaching each other, at least one of the valve body and the retaining body is elastically deformed relative to the other, so that during the approaching process, the protrusion of one slides on the contact surface of the other until it is inserted into the cavity of the other, and is then retained in the cavity due to the elastic deformation generated during the relative sliding process, and the cavity is formed to prevent the retaining body from moving in a direction parallel to the central axis (Z) by an obstruction portion.

2. The automatic two-way valve according to claim 1, characterized in that: The retaining body comprises a first retaining body (140) suitable for retaining the first elastic element (130) and a second retaining body (145) suitable for retaining the second elastic element (135), wherein the second retaining body (145) comprises a cup-shaped portion, the cup-shaped portion is provided with a through hole (195) and a through port (200), the through hole (195) is at least partially aligned with the central pipe (10) of the valve body, the through port (200) is eccentric relative to the through hole (195), and is suitable for being at least partially closed by the second shielding member (110) when the fluid at the fourth opening (90) of the peripheral pipe (75) overcomes the force of the second elastic element (135).

3. The automatic two-way valve according to claim 1 or 2, characterized in that: The valve body (5) is integral and made of a single material.

4. The automatic two-way valve according to claim 3, characterized in that: The single material is a metal material selected from the group consisting of stainless steel, brass alloys and aluminum alloys.

5. An axial piston pump for pumping a liquid, comprising: - base (210); - a head (225) fixed to said base (210); - a plurality of cylinders (230) having central axes parallel to each other and formed in the head (225); - a plurality of pistons (310), each of the pistons (310) sliding in a corresponding cylinder of the plurality of cylinders to pump a liquid; - a tilting piston (215) configured to drive the piston (310) to slide within the corresponding cylinder (230); and - An automatic two-way valve according to any of the preceding claims for each of the cylinders (230).

6. The pump according to claim 5, characterized in that Each cylinder (230) is formed in the head like a blind hole, and each automatic two-way valve is accommodated in and closes the bottom of the corresponding cylinder (230), the bottom being shaped so that the automatic two-way valve is oriented so that the central axis of the central pipe (10) is parallel to the central axis of the cylinder.

7. The pump according to claim 6, characterized in that Each cylinder (230) comprises a bushing (290) which is inserted into the cylinder and in which the corresponding piston (310) slides, the bushing (290) extending from the automatic two-way valve to at least one first annular sealing gasket surrounding the piston (310).

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