Automatic two-way valve and pump equipped with the valve

Abstract

A valve for a pump includes: a valve body; a central conduit having first and second openings at first and second ends of the valve body; a peripheral conduit having first and second openings at a side surface and a second end of the valve body; a first blocking body movable between a closed position and an open position, blocking the first opening of the central conduit in the closed position and being spaced from the first opening of the central conduit in the open position; a first elastic element for generating a force to keep the first blocking body in the closed position; a second blocking body movable between a closed position and an open position, blocking the second opening of the peripheral conduit in the closed position and being spaced from the second opening of the peripheral conduit in the open position; and a second elastic element for generating a force to keep the second blocking body in the closed position. The valve body includes a first portion having the first opening of the central conduit, a second portion having the second opening of the central conduit, and a third portion therebetween, the surface hardness of the material of the third portion being lower than that of the other two portions.

Description

Technical Field

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

[0002] Automatic double-acting 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] A known embodiment of an automatic double-acting 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 configured 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 comprises a first blocking body and a second blocking body, wherein the first blocking body is used for sealingly closing a first opening of the central pipe under the thrust of the first elastic element, and the second blocking body is used for sealingly closing a second opening of the peripheral pipe under the thrust of the second elastic element.

[0006] In particular, the valve is configured such 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 opening the second opening of the peripheral conduit by the second blocking body. 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 opening the first opening of the central conduit by the first blocking body.

[0007] The valve body must be made of brass or steel in order to withstand the mechanical stresses caused by the continuous opening and closing of the barrier body, which complicates the machining of the valve body and therefore also implies relatively high costs in terms of the cost of the actual material used.

[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 double-acting valve for a high-pressure pump, comprising:

[0011] - valve body;

[0012] a through-type central conduit that 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 side surface of the valve body, included between a first end and a second end, and with a second opening formed in a second end of the valve body;

[0014] a first blocking body movable between at least a closed position, in which it sealingly blocks the first opening of the central duct, and an open position, in which it is spaced apart 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 blocking body in its closed position;

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

[0017] - a second elastic element configured to generate a force suitable for keeping said second blocking body in its closed position,

[0018] Wherein, the valve body includes a first part, a second part and a third part, the first part is configured with the first opening of the central pipe, the second part is configured with the second opening of the central pipe, the third part is inserted between the first part and the second part, and the material making the third part has a lower surface hardness than the material making the first part and the second part.

[0019] Thanks to this solution, the construction of the valve implies simpler machining (for example, since the first peripheral duct is made of a material with a lower surface hardness), and also enables more efficient and rational use of the material that must withstand the wear caused by contact with the barrier body. In addition, the material used for the third part can have a lower density, so the valve can be lighter.

[0020] For example, the first portion and the second portion may be made of a material having a surface hardness of at least 160 Hb.

[0021] According to one aspect of the present application, the first portion and the second portion may be made of a metal material selected from a metal material group including stainless steel and brass alloy.

[0022] This material group ensures good machinability while at the same time having sufficient hardness.

[0023] According to another aspect of the present application, the third portion may be made of a material having a compressive strength higher than 60 MPa.

[0024] For example, the third portion is made of a material selected from the group consisting of aluminum alloy and plastic material.

[0025] In this way, the valve will be particularly light, but at the same time durable.

[0026] One aspect of the present invention contemplates that the first portion may include a rod sized to be insertable with an interference fit into a corresponding receptacle formed in the third portion.

[0027] Thanks to this solution, the assembly does not require any additional connections such as threads or welding.

[0028] Another aspect of the present invention contemplates that the valve may include a retaining body, which is fixed to the valve body and is configured to hold one of the first elastic element and the second elastic element in an appropriate position so that the elastic element exerts a force on the corresponding blocking body that is suitable for keeping the corresponding blocking body in its closed position.

[0029] Thanks to this solution, it is not necessary to carry out a process to form in the head of the pump that is to house the valve a shoulder suitable for holding the elastic element in position relative to the valve body, which makes it possible to reduce planning and production times and costs. In addition, since the retaining body is fixed relative to the valve body, the assembly operations of the pump are simplified and accelerated.

[0030] According to one aspect of the present invention, the retaining body may be removably fixed to the valve body.

[0031] This feature may make maintenance operations of the valve easier, for example enabling replacement of the elastic element.

[0032] For example, the retaining body may be secured to the valve body by a snap-fit ​​mechanism.

[0033] In this way, assembly and disassembly of the valve is particularly practical and quick and does not require the use of tools.

[0034] According to another aspect of the present invention, the retaining body may be configured to retain the second elastic element in place.

[0035] Typically, as described herein, the second end is the end that faces the pumping chamber so that no shoulder is required in the cylinder or the cylinder bushing (if a bushing is designed to be used) to hold the retaining body in place.

[0036] According to another aspect of the present invention, the valve may include two retaining bodies, one retaining body being a first retaining body fixed to the valve body and configured to hold the first elastic element in an appropriate position, and the other retaining body being a second retaining body fixed to the valve body and configured to hold the second elastic element in an appropriate position.

[0037] Another aspect of the present invention contemplates that the second retaining body may include a cup-shaped portion, which is configured with a through hole and a through opening, the through hole being at least partially aligned with the central hole of the valve body, the through opening being eccentric relative to the through hole and being suitable for being closed by the second blocking body when the fluid at the outlet of the peripheral pipe overcomes the force of the second elastic element.

[0038] In this way, a faster closing of the second barrier body is ensured when the pressure in the pumping chamber of the pump in which the valve is installed increases. In addition, this feature enables a faster opening of the second barrier body, since it enables the fluid present in the retaining body to be discharged faster. These advantages are relative to when there is only a through hole in the retaining body.

[0039] The present invention also provides an axial piston pump for pumping liquid, comprising:

[0040] - base;

[0041] - a head of the cylinder, which is fixed to the base;

[0042] - a plurality of cylinders having central axes parallel to one another and formed in the head,

[0043] - a plurality of pistons, each of said pistons sliding in a corresponding cylinder of said plurality of cylinders to pump a liquid;

[0044] - a tilting plate configured to control the sliding of said pistons in their respective cylinders; and

[0045] - An automatic double-acting valve according to any one of the preceding claims for each of the cylinders.

[0046] Thanks to this solution, a pump is provided which is quicker to design and quicker to assemble than prior art devices.

[0047] According to one aspect of the invention, each cylinder may be formed in the head in the form of a blind hole, and each valve may be accommodated 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 so that the valve blocks the bottom.

[0048] Thanks to this solution, the head is more resistant to fatigue loads due to pressure pulsations, and therefore the head can be made of a material (such as aluminum) that is less resistant to fatigue loads than materials such as stainless steel and brass currently used. Aluminum has the advantage of being easier to process and lighter than stainless steel and brass alloys. In particular, it has the advantage that, since this construction can reduce the number of holes through the head for inserting the valves compared to the pumps of the prior art, the geometry of the head that would lead to a notch effect and thus reduce the fatigue resistance of the head is reduced. In particular, in the known axial piston pumps equipped with a disk, each cylinder uses an automatic non-return suction valve and an automatic non-return 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 bottom. The construction of the pump according to the invention makes it unnecessary to make such a hole at the above-mentioned position, thereby improving the fatigue resistance of the head.

[0049] Furthermore, the valve essentially acts as a shield for the bottom wall against fatigue pressure changes occurring in the pumping chamber.

[0050] Furthermore, this configuration makes it possible to form all pump connections for suction and delivery on only one side.

[0051] To complete the improvements in fatigue stress resistance described above, according to another aspect of the invention, each cylinder comprises a bushing inserted in the cylinder itself, inside which the corresponding piston slides, the bushing extending from the automatic double-acting valve to at least one first annular sealing gasket surrounding the piston.

[0052] In this way, since the valve and the bushing substantially isolate the head from said pulsations, the fatigue strain to which the head is subjected can be further reduced.

[0053] According to another aspect of the present invention, the head is made of die-cast aluminum.

[0054] In this way, the head is light and easy to process. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] 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 aid of the accompanying drawings.

[0056] Figure 1 is a front view of an automatic double-acting valve according to the present invention.

[0057] Figure 2It is shown in the suction steps. Figure 1 Cross-sectional view of the valve in plane II-II.

[0058] Figure 3 It is a follow-up to the delivery steps. Figure 1 Cross-sectional view of the valve in plane II-II.

[0059] Figure 4 is a top view of a pump equipped with a valve according to the present invention.

[0060] Figure 5 yes Figure 4 A cross-section of the pump along plane VV.

[0061] Figure 6 yes Figure 4 Sectional view of the pump along plane VI-VI. DETAILED DESCRIPTION

[0062] Special reference Figures 1 to 3 , reference numeral 1 represents the automatic double-acting valve as a whole, hereinafter referred to as valve 1.

[0063] It should be noted that an automatic valve refers to a valve that is configured to automatically open once a predetermined 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 utilizes a pressure difference.

[0064] It should also be noted that a double-acting 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 the suction pipe, the second environment is the pumping chamber, and the third environment is the delivery pipe.

[0065] The valve 1 comprises a valve body 5 which is penetrated from one side to the other by a central duct 10 which is provided with a first opening 15 formed in the valve body itself and an opposite second opening 20. That is, said 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.

[0066] Such an end is the axial end 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 constructed like a body of revolution relative to said central axis Z.

[0067] The central conduit 10 may be rectilinear and is preferably configured with a cylindrical inner surface.

[0068] In the illustrated embodiment, the valve body 5 includes a first portion 30, a second portion 35 and a third portion 40, the first opening 15 is formed in the first portion 30, the second opening 20 is formed in the second portion 35, the third portion 40 is inserted between the first portion and the second portion (for example, directly and in contact), and is penetrated by the central pipe 10 like the first portion and the second portion.

[0069] Thus, the first end 25A is provided by the first portion 30 and the second end 25B is provided by the second portion 35 .

[0070] The first portion 30 comprises a cylindrical side surface 30 a coaxial with the central pipe 10 , ie coaxial with the central axis Z.

[0071] For example, the first portion comprises a seat 45 shaped like an annular void formed at the cylindrical side surface of the first portion itself and suitable for housing a sealing gasket 50 .

[0072] The second portion 35 has a first cylindrical side surface 35 a and a second cylindrical side surface 35 a ′ coaxial with each other and with the central pipe 10 , i.e., coaxial with the central axis Z. For example, the second portion 35 includes a seat 55 shaped like an annular gap formed at the first cylindrical side surface 35 a and adapted to accommodate a sealing gasket 60 .

[0073] The second cylindrical side surface 35 a ′ is closer to the third portion than the first cylindrical side surface 35 a , has a larger average radius than the first cylindrical side surface 35 a , and is connected to the first cylindrical side surface 35 a by a flat surface 70 transverse to (e.g., perpendicular to) the central axis Z. In particular, the flat surface 70 partially defines the seat 55 .

[0074] The third portion 40 is cylindrical and has a larger average radius than the first portion and the first cylindrical side surface 35a, thereby protruding relative to the first portion and the first cylindrical side surface 35a in the radial direction relative to the central axis Z. In particular, the third portion has a cylindrical side surface 40a that protrudes radially relative to the cylindrical side surface 30a of the first portion, and has substantially the same diameter as the second cylindrical side surface 35a'.

[0075] The valve body 5 comprises a first abutment surface 65 and an opposite second abutment surface, which are transverse to the central axis Z. In particular, the abutment surfaces 65 , 70 are flat (eg annular), preferably lying on a plane perpendicular to the central axis Z.

[0076] In the illustrated embodiment, the first abutment surface 65 is formed in the third portion 40 of the valve body 5, and the second abutment surface is defined by a flat surface 70 disposed radially between the first cylindrical side surface 35a and the second cylindrical side surface 35a'. For example, the first abutment surface 65 faces the first portion 30, and the second abutment surface faces the first cylindrical side surface 35a.

[0077] The first abutment surface 65 and the second abutment surface are suitable for achieving a correct positioning and locking of the valve body 5 when the valve body 5 is inserted into a corresponding seat formed in the pump.

[0078] The first part and the second part are made of a material having a higher surface hardness than the material made of the third part. For example, the first part and the second part are made of a material having a surface hardness of at least 160Hb.

[0079] Furthermore, the first portion and the second portion are made of a material having a fatigue limit at least equal to 60 MPa.

[0080] The first part and the second part can be made of a material selected from the following material group, for example: stainless steel, brass alloy and aluminum alloy. In the case of being made of aluminum, the first part and the second part must be surface hardened later. Preferably, the first part and the second part are made of the same material.

[0081] The third part is composed of a material having a compressive strength higher than 60 MPa, preferably also having a compressive strength lower than 8.7 kg / dm 3 Made of material with a density of

[0082] For example, the third part may be made of aluminum alloy or plastic material.

[0083] The first portion 30, the second portion 35, and the third portion 40 are each formed in a respective body different from the other two, and are rigidly (eg, mechanically) fixed together.

[0084] In particular, the first part 30 and the second part 35 are rigidly fixed to the third body 40 by means of interference fit. In particular, the first part and the second part respectively comprise a rod 30b and a rod 35b, which are inserted into corresponding seats 40b, 40c formed in the third part 40 by means of interference fit.

[0085] In the embodiment shown in the drawings, the rods 30b and 35b are shaped like cylindrical tubular bodies coaxial with the central axis Z, for example, each defining a respective portion of the central conduit 10. That is, each rod has a cylindrical side surface defining a respective portion of said central conduit.

[0086] The seats 40b and 40c are respectively provided with a cylindrical surface coaxial with the central axis Z, which has a smaller diameter than the outer diameter of the cylindrical tubular body of the corresponding rod. For example, the seats are provided with a shoulder adapted to come into contact with the corresponding rod 30b, 35b and lying on an axis transverse to the central axis Z.

[0087] Between the seats 40 b and 40 c there is provided a cylindrical surface which defines a portion of the central duct which is inserted between the portions of the central duct 10 defined by the rods.

[0088] The diameter of this cylindrical surface is equal to the inner diameter of the cylindrical tubular body in which the rods 30b, 35b are arranged.

[0089] The valve 1 comprises a peripheral duct 75 formed in the valve body (for example in the second portion 35 and in the third portion 40 ) and eccentric to and distinct from the central duct 10 .

[0090] Said peripheral duct 75 comprises a first opening 80 formed in a lateral surface of the valve body 5 comprised between the first end 25A and the second end 25B, for example in the third portion 40, i.e. in the cylindrical lateral surface 40a of the third portion 40. In particular, the first opening 80 opens into an annular groove 85 formed in the third portion and opening on the cylindrical lateral surface 40a of the third portion itself.

[0091] The peripheral duct 75 further comprises a second opening 90 , in particular, the peripheral duct has only the first opening 80 and the second opening 90 .

[0092] The second opening 90 is formed in the second end of the valve body 5 (e.g., thus in the second portion 35) and is different from the second opening 20 of the central duct 10. Preferably, the second opening 90 is arranged with its central axis parallel to the central axis Z, in particular, also with its central axis perpendicular to the central axis of the first opening 80.

[0093] For example, the second opening 20 of the central conduit 10 and the second opening 90 of the peripheral conduit 75 are disposed transversely on the same plane (e.g., a plane perpendicular to the central axis Z). That is, the second end of the valve body (i.e., the second portion 35) includes a flat surface (e.g., a flat surface perpendicular to the central axis Z) in which the second opening 90 of the peripheral conduit 75 is formed.

[0094] The peripheral duct preferably has a substantially circular cross-section relative to its longitudinal axis.

[0095] For example, the peripheral duct 75 comprises at least one rectilinear portion terminating in the second opening 90 and having a longitudinal axis parallel to the central axis Z.

[0096] In particular, the peripheral duct includes a first portion that is linear. The first portion is shaped substantially like a through hole with a circular cross section, which is completely formed in the second portion 35 and includes a second opening 90. In addition, the peripheral duct 75 includes a curved second portion that is completely formed in the third portion 40. The second portion includes a first opening 80 and is in direct communication with the first portion. For example, the second portion of the peripheral duct is generally L-shaped.

[0097] In the embodiment shown, the valve comprises a plurality of peripheral ducts 75 , each of which is constructed as described above and which is arranged circumferentially relative to the central duct 10 , ie relative to the central axis Z.

[0098] The valve 1 comprises a first blocking body 95 which is movable between at least a closed position, in which the first blocking body 95 sealingly blocks the first opening 15 of the central conduit 10, and an open position, in which the first blocking body 95 is spaced from the first opening 15 of the central conduit and allows fluid to pass through the first opening itself.

[0099] In particular, the first blocking body comprises a contact surface 100 which, when the first blocking body is in the closed position, comes into contact, at least along the closed periphery, with a seat 105 of the first blocking body itself formed at the first opening 15 in the valve 5. In the embodiment shown, the first blocking body 95 is provided with a frustoconical contact surface 100 and the seat 105 is provided with a matching frustoconical contact surface.

[0100] The valve 1 further comprises a second blocking body 110 which is movable between at least a closed position and an open position. In the closed position, the second blocking body 110 sealingly blocks the second opening 90 of the peripheral pipe 75. In the open position, the second blocking body 110 is spaced apart from the second opening 90 of the peripheral pipe 75 and allows fluid to pass through the second opening itself.

[0101] In particular, the second blocking body 110 comprises a contact surface 115 which, when the second blocking body is in the closed position, contacts at least along the closed periphery a seat 120 of the second blocking body itself formed at the second opening 90 in the valve 5. For example, the contact surface 115 is flat and the seat 120 is provided with a matching flat contact surface. In particular, in the embodiment shown, the flat contact surface of the second blocking body is annular and is shaped to contact a flat surface into which the second openings 90 of the plurality of peripheral ducts 75 open.

[0102] The second blocking body 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 blocking body itself.

[0103] For example, the through hole 125 is coaxial with the central axis Z and is located internally relative to the flat contact surface 115 of the second blocking body 110 .

[0104] Furthermore, the through hole 125 may have a diameter greater than a diameter of the second opening 20 of the central pipe 10 .

[0105] The valve 1 comprises a first elastic element 130 and a second elastic element 135, wherein the first elastic element 130 is configured to generate a force suitable for keeping the first blocking body 95 in the closed position, and the second elastic element 135 is configured to generate a force suitable for keeping the second blocking body 110 in the closed position. The elastic element is preferably a spring, such as a helical compression spring.

[0106] Furthermore, the valve 1 comprises retaining bodies 140, 145, which are, for example, rigidly (i.e. without any remaining degrees of freedom) fixed to the valve body 5 and are 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 blocking body in the closed position.

[0107] In particular, the retaining bodies 140, 145 are removably fixed to the valve body 4, that is, the retaining bodies 140, 145 are fixed to the valve body via a connector that can both fix the retaining bodies 140, 145 to the valve body and remove the retaining bodies 140, 145 from the valve body.

[0108] In particular, the retaining body 140, 145 is fixed to the valve body by a snap-fit ​​mechanism, ie the connection comprises a snap-fit ​​mechanism.

[0109] The snap-fit ​​mechanism is of a type in which at least one of the valve body and the retaining body 140, 145 is elastically deformed relative to the other during the movement of the valve body and the retaining body 140, 145 approaching each other, so that during the said approaching movement, 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 of the other 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.

[0110] In particular, the retaining body 140, 145 may include at least one end portion provided with a protrusion and a wall deformable by bending, from which the protrusion projects 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.

[0111] The holding bodies 140 , 145 have a portion shaped like a cup, in which the respective blocking body is accommodated.

[0112] For example, the retaining body 140, 145 comprises an abutment surface for the blocking body, which abutment surface is spaced from the valve body 5 and preferably perpendicular to the central axis Z, which abutment surface defines the end of travel of the blocking body when it is away from the valve body. In particular, this abutment surface defines the maximum open position of the blocking body itself, in which the distance between the blocking body and the corresponding opening configured to be closed by the blocking body is the largest.

[0113] The contact abutment surface is in contact with a surface of a corresponding blocking body, which is opposite to the contact surface of the corresponding blocking body.

[0114] 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.

[0115] Furthermore, the holding body comprises a surface which is suitable for serving as a guide for a corresponding blocking body.

[0116] In the illustrated embodiment, the valve includes a first retaining body 140 and a second retaining body 145 .

[0117] The first retaining body 140 is fixed to the valve body 5, in particular to the first part 30 (e.g. rigidly, i.e. without any remaining 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 holding the first blocking body 95 in the closed position.

[0118] The first retaining body 140 may be fixed to the valve body in a removable manner, that is, fixed to the valve body via a connecting piece, which can both fix the first retaining body 140 to the valve body 5 and remove the first retaining body from the valve body 5 .

[0119] For example, the first retaining body 140 is fixed to the valve body by means of a snap-fit ​​mechanism 150 , ie the connection comprises a snap-fit ​​mechanism.

[0120] In particular, the first retaining body 140 comprises a cup-shaped portion, the recess of which faces the valve body 5 (i.e., towards the first part 30 of the valve body), and the snap-fit ​​mechanism 150 comprises an end portion that can be deformed by bending, which is formed at the end of the cup-shaped body facing the valve body, and which is provided with a protrusion 155, which is, for example, annular and concentric with the central pipe 10, which protrudes toward the internal volume of the cup-shaped portion. Then, the snap-fit ​​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., formed 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.

[0121] The first retaining body may comprise an abutment surface 165 for the first blocking body 95. This abutment surface is spaced from the valve body 5, preferably perpendicular to the centre axis Z, and defines the end of travel of the first blocking body 95 away from the valve body.

[0122] Furthermore, the first retaining body may include a through hole 125 formed in a bottom wall of the cup-shaped portion opposite to a portion of the first retaining body contacting the valve body 5. The fluid flowing through the first opening 15 of the central pipe 10 passes through the through hole 125.

[0123] The second retaining body 145 is fixed to the valve body 5, in particular to the second part 35 (e.g. rigidly, i.e. without any remaining degrees of 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 holding the first blocking body 110 in the closed position.

[0124] The second retaining body 145 may be fixed to the valve body 5 in a removable manner, that is, fixed to the valve body 5 via a connecting piece, which can both fix the second retaining body 145 to the valve body 5 and remove the second retaining body from the valve body 5 .

[0125] For example, the second retaining body 145 is fixed to the valve body by means of a snap-fit ​​mechanism 175 , ie the connection comprises a snap-fit ​​mechanism.

[0126] In particular, the second retaining body 145 comprises a cup-shaped portion, the recess of which faces the valve body 5 (i.e., towards the second part 35), and the snap-fit ​​mechanism 175 comprises an end portion that can be deformed by bending, which is formed at one end of the cup-shaped body facing the valve body, and which is 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 ​​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., formed in the second part 35) and is suitable for accommodating the protrusion 180 of the second retaining body, and which is shaped to form a connection with the protrusion through an obstruction.

[0127] The second retaining body 145 may comprise an abutment surface 190 for the second blocking body 110. This abutment surface 190 is spaced from the valve body 5, preferably perpendicular to the central axis Z, and defines the end of travel of the second blocking body 110 away from the valve body.

[0128] The abutment surface 190 is in contact with a surface of the second blocking body which faces in the opposite direction to the surface of the second blocking body itself which is in contact with the seat.

[0129] The second retaining body 145 may include a through hole 195 formed in the bottom wall of the cup-shaped portion, the bottom wall being opposite to the portion of the second retaining body in contact with the valve body 5. The through hole 195 is directly and always in fluid communication with the through hole 125 of the second blocking body, 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.

[0130] The second retaining body 145 may also include at least one through opening 200 formed in the cup-shaped portion and configured such that the second blocking body 110 only partially blocks the through opening when the second blocking body is in contact with the abutment surface 190 (ie, in the maximum open position).

[0131] 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 .

[0132] The through opening 200 is eccentric relative to the through hole 195 and is, for example, located radially further outward relative to the abutment surface 190 of the second blocking body (relative to the center axis Z). In particular, the second blocking body 110 protrudes radially relative to the abutment surface 190 of the second retaining body (away from the center axis Z), and the through opening 200 is at least partially aligned with this protruding portion in a direction parallel to the center axis Z.

[0133] Thanks to the through-opening 200 , the second blocking body 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 located outside the cup of the second retaining body 145 .

[0134] Preferably, the second holding body 145 includes a plurality of through openings 200 which are arranged circumferentially around the through hole 195 .

[0135] In the embodiment shown, the first and second retaining bodies are cup-shaped, that is, the cup-shaped portion basically constitutes the retaining body itself. However, it is not excluded that in embodiments not shown, the shape of the retaining body can be similar to a rod or a folded sheet.

[0136] Special reference Figure 4 and Figure 5 , 205 represents a high-pressure axial piston pump, which is equipped with at least one valve 1 for adjusting the pumping flow. In particular, 205 is a high-pressure axial piston pump, and is a high-pressure axial piston pump of a rotating disk type inclined at a fixed inclination.

[0137] 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 drive shaft from outside the axial piston pump 205 , and the flange 220 is used to be fixed to a motor equipped with the drive shaft.

[0138] 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.

[0139] 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 including a corresponding pumping chamber 235, the pumping chamber 235 is used to contain liquid and is provided with respective central axes parallel to each other.

[0140] These centre axes are also preferably parallel to the axis A of rotation.

[0141] The head 225 may be made as a single body, which may be obtained by machining a single body obtained by solidifying a single casting or injection of material into a mold.

[0142] For example, the plurality of cylinders 230 are radially arranged along a common axis, with the central axis being 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 arranged at angles equidistant from each other along an imaginary circle centered on the common axis. In the illustrated embodiment, the common axis of the plurality of cylinders 230 is the rotation axis A.

[0143] Preferably, the cylinder 230 is made into a blind hole, and each cylinder 230 is provided with an opening 240. 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 to say, relative to the axial piston pump of the prior art, the axial piston pump of the present application is not provided with a hole passing through the second face 250.

[0144] 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.

[0145] Each cylinder comprises a bottom opposite to the corresponding opening 240, and the bottom comprises a bottom wall 260, which is disposed transversely to (eg perpendicular to) a plane of the axis of the cylinder itself. For example, the bottom wall 260 is spaced apart from the second face of the head rather than at zero distance.

[0146] The valve 1 is accommodated at a bottom which is shaped such that the valve 1 is arranged with the second opening 20 of the central duct 10 facing the opening of the cylinder.

[0147] The valve 1 is completely accommodated in the bottom.

[0148] 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.

[0149] The first retaining body 140 is completely contained within the volume partially defined by the first cylindrical surface 265 and the bottom wall 260 .

[0150] 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 located farthest from the first abutment surface 65 .

[0151] 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 dimension of the first holding body 140 in a direction perpendicular to the central axis of the cylinder. That is to say, 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.

[0152] In other words, the bottom does not include any surface that contacts the first retaining body 140 so as 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.

[0153] Thus, the sealing gasket 50 housed in the seat 45 formed in the first portion 30 is pressed between its own seat and the first cylindrical surface 265 .

[0154] The bottom also comprises a second cylindrical surface 270 which extends in the direction of the opening 240 and is directly connected to the first cylindrical surface 265 by a step 275 against which the first abutment surface of the valve 1 abuts. The second cylindrical surface 270 has a diameter suitably 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.

[0155] 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 relative to the second cylindrical surface 270.

[0156] The axial piston pump 205 also includes a cylindrical tubular bushing 290, each of which is inserted in the cylinder 230, and the bushing 290 is provided with an annular abutment surface 295 at its axial end, which is arranged transversely on a plane transverse to the center axis Z (for example, perpendicular to the center axis Z) and contacts the second abutment surface of the valve 1.

[0157] The base and bushing are shaped so that when the head 225 is secured to the base 210, the bushing 290 pushes against the second abutment surface of the valve body 5, thereby holding the first abutment surface 65 of the valve body in contact with the step 275, thereby substantially holding the valve 1 in its seat.

[0158] In the embodiment shown, between the axial end of the bushing 290 (the axial end opposite to the axial end in contact with the valve 1) and the base, there is at least one annulus suitable for accommodating the sealing gasket 300 and which is pressed between the bushing and the base itself when the head is fixed to the base.

[0159] The bushing comprises an inner surface 305 having a diameter at the annular abutment surface 295 to accommodate the second portion 35 of the valve body in an appropriately sized manner (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 second cylindrical side surface 25a' of the second portion 35 of the valve body 5.

[0160] Thus, the sealing gasket 60 housed in the seat 55 formed in the second portion 35 is pressed between its own seat and said inner surface 305 .

[0161] There is always a non-zero gap between the inner surface 305 of the bushing and the second retaining body 145 .

[0162] Furthermore, the profile of the inner surface 305 defined by the section containing the central axis of the cylinder forms, in each of its parts, an acute angle of less than 30° with an axis parallel to the central axis Z and intersecting the profile itself.

[0163] In other words, the bushing does not include any such surface, which contacts the second retaining body 145 so as to keep the second retaining body 145 in contact with the valve body 5 or keeps the diaphragm in contact with the second retaining body so that it presses 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.

[0164] In the embodiment shown, the inner surface 305 of the bushing comprises a first cylindrical portion, a second truncated cone portion and a third cylindrical portion. The first cylindrical portion is appropriately sized to receive the second portion of the valve body. The second truncated cone portion is directly adjacent to the first portion and its profile 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 cylindrical portion is directly adjacent to the second portion and has a smaller diameter relative to the first portion.

[0165] The bushing is preferably made of aluminum.

[0166] 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 bushing 290) driven by 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., the cylinder bushing) and the valve 1.

[0167] In particular, the volume of the pumping chamber 235 is at least partially defined by the piston 310 , the cylinder (ie, the liner of the cylinder), the valve body, the center conduit 10 , and the first barrier body 95 .

[0168] 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.

[0169] 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 held in contact with an annular guide 325 by a corresponding elastic element 320, which rests on a flat annular surface of the rotating disk 215.

[0170] Each elastic element 320 has a first end and a second end, the first end is connected to the base 210 , and the second end is connected to the piston 310 (eg, the piston 310 close to the second end).

[0171] The axial piston pump 205 includes a plurality of annular gaskets 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 bushing) to prevent fluid communication between the pumping chamber 235 and the base 210.

[0172] 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 .

[0173] The guide sleeve 326 communicates with an opening 240 of a corresponding cylinder formed in the head 225 .

[0174] The axial piston pump 205 may include a plurality of clamping screws configured to secure the head to the base, the plurality of clamping screws being inserted into a same number of through holes formed in the head.

[0175] The pump comprises at least one suction duct 330 for the cylinder, comprising a hole formed in the head 225 and provided with an inlet opening 335 formed in the lateral surface 255 of the head.

[0176] The suction duct also comprises a plurality of outlet openings 340 , one for each cylinder. The outlet openings 340 are formed in the bottom of the cylinder, in particular at the second cylindrical surface 270 .

[0177] 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.

[0178] The pump includes a suction manifold connected to a suction conduit 330 .

[0179] 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 cover 360 sealingly closing the respective outlet opening.

[0180] 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 .

[0181] The longitudinal axis of each bore 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 bore of the delivery conduit is perpendicular to the axis of the cylinder.

[0182] The pump further comprises a delivery manifold 370 adapted to merge with the delivery duct 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.

[0183] The longitudinal axis of the bore of the suction 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.

[0184] The head is preferably made of aluminium.

[0185] In particular, the head can be made of aluminium, since the liner and valve of the cylinder are shaped and positioned so that the pumping chamber is isolated from the cylinder and thus the head from pressure pulsations which cause problems in terms of fatigue wear.

[0186] The operation of the valve and the pump equipped with the valve is as follows.

[0187] When the pump performs the suction step, that is, when the piston descends toward the bottom dead center, a low pressure is generated in the pumping chamber, and due to the low pressure, the first elastic element 130 keeps the first blocking body in the closed position, thereby isolating the pumping chamber 235 from the delivery chamber, and the fluid present in the suction pipeline can overcome the force of the second elastic element 135, thereby placing the second blocking body 110 in the open position. In this way, the fluid from the delivery pipeline flows into the pumping chamber.

[0188] When the piston returns from the bottom dead center to the top dead center, the pump performs a pumping step, during which the increase in pressure in the pumping chamber enables the second elastic element 135 to place the second blocking body in the closing step, and the pressurized fluid through the central channel pushes the first blocking body 95 to overcome the force of the first elastic element 130, thereby placing the first blocking body in the open position and delivering the fluid to the delivery pipeline.

[0189] The invention thus conceived is susceptible of numerous modifications and variations, all of which are within the scope of the inventive concept.

[0190] Moreover, all the details may be replaced by other technically equivalent elements.

[0191] 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 double-acting valve (1) 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 (75) formed in the valve body (5) eccentrically with respect to the central duct (10) and provided with a third opening (80) formed in a side surface 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 blocking body (95) movable between at least a closed position, in which the first blocking body (95) sealingly blocks the first opening (15) of the central duct (10), and an open position, in which the first blocking body (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 blocking body (95) in its closed position; - a second blocking body (110) movable between at least a closed position, in which the second blocking body (110) sealingly blocks the fourth opening (90) of the peripheral duct (75), and an open position, in which the second blocking body (110) is spaced from the fourth opening (90) of the peripheral duct (75) and allows fluid to pass through the fourth opening itself; as well as - a second elastic element (135) configured to generate a force suitable for maintaining the second blocking body (110) in its closed position, The valve body comprises a first part (30), a second part (35) and a third part (40), wherein the first part (30) is provided with the first opening (15) of the central pipe (10), the second part (35) is provided with the second opening (20) of the central pipe (10), the third part (40) is inserted between the first part and the second part, and the material of the third part has a lower surface hardness than the material of the first part and the second part, and the third part (40) is made of a material selected from a material group including aluminum alloy and plastic material.

2. The automatic double-acting valve (1) according to claim 1, characterized in that: The first portion (30) and the second portion (35) are made of a material having a surface hardness of at least 160 Hb.

3. The automatic double-acting valve (1) according to claim 1, characterized in that: The third part (40) is made of a material having a compressive strength higher than 60 MPa.

4. The automatic double-acting valve (1) according to claim 1, characterized in that: The first part (30) and the second part (35) are made of a metal material selected from a metal material group consisting of stainless steel, brass alloy and aluminum alloy.

5. The automatic double-acting valve (1) according to claim 1, characterized in that: The first part (30) includes a rod (30b) having a size designed to be insertable into a corresponding receiving seat (40b) formed in the third part (40) by interference fit.

6. The automatic double-acting valve (1) according to claim 1, characterized in that: A retaining body is included, which is 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, thereby applying the force to the corresponding first blocking body (95) or the second blocking body (110).

7. The automatic double-acting valve (1) according to claim 6, characterized in that: The retaining body is removably fixed to the valve body (5).

8. The automatic double-acting valve (1) according to claim 7, characterized in that: The retaining body is fixed to the valve body (5) by a snap-fit ​​connection mechanism.

9. An axial piston pump (205) for pumping a liquid, comprising: - base (210); - a head (225) of the cylinder, which is 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 plate (215) configured to control the sliding movement of the piston (310) within the corresponding cylinder (230); and - An automatic double-acting valve (1) according to any one of claims 1 to 8 for each of said cylinders (230).

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