A normally open piston cooling control solenoid valve

Abstract

The present invention relates to a normally open piston cooling control solenoid valve, in particular to a normally open piston cooling control solenoid valve applied to an engine. The solenoid valve includes a coil, a bracket, a valve sleeve, a valve core, a spring and a filter screen. An internal axial through hole, an oil outlet hole communicating the internal axial through hole with the outside of the valve sleeve, and an oil inlet cavity are arranged in the valve sleeve. After the oil enters the normally open piston cooling control solenoid valve, it is filtered by the filter screen and then flows out from the oil inlet cavity through the oil outlet hole; when the coil is powered off, the spring pushes the valve core to move upward to keep the oil inlet cavity and the oil outlet hole in communication, so that the solenoid valve is normally open. The oil inlet cavity adopted by this solenoid valve is a cavity without components obstructing the flow of oil inside, which makes the flow resistance of the oil small and the flow rate of the oil flowing out large; this solenoid valve is provided with a buffer device to absorb shocks and reduce noise. In addition, this solenoid valve also has beneficial effects such as high process efficiency and high reliability.

Description

Technical Field

[0001] The present invention relates to a normally open piston cooling control solenoid valve, particularly a solenoid valve applied to an engine. Background Art

[0002] During the operation of an engine, the engine piston bears high temperature loads, which may cause the piston to overheat and be damaged. Therefore, it is necessary to cool the piston under heavy loads. To ensure reliable piston cooling, a large flow rate of coolant is required. However, if the piston temperature is too low, the heat loss will be too large, affecting the performance of the engine and the pollutant emission level. Therefore, it is necessary to stop cooling the piston under light loads to control the piston temperature within an appropriate operating temperature range. For heavy-duty engines with high thermal loads, such as engines with high intake supercharging and high compression ratios, the engine piston needs to be cooled under most load conditions, and only under certain light load conditions, such as cold engine conditions or idle conditions, etc., does the engine piston not need to be cooled. For this reason, the conventional method in this field is to adopt a normally open piston cooling control system. For example, a normally open piston cooling control solenoid valve is used to control the opening and closing of the piston cooling oil circuit.

[0003] In current engine piston cooling control solenoid valves, a spring seat and a return spring are arranged inside the oil inlet, and an armature and a fixed iron core are installed with a bushing closed at the top. The spring seat and the return spring inside the oil inlet impede the oil inlet and outlet of the control valve. The non-magnetic bushing forms a magnetic path gap in the magnetic path between the armature and the top cover, significantly increasing the magnetic resistance of the magnetic path. Therefore, the bushing should be as thin as possible to minimize the magnetic resistance of the magnetic path. However, it is difficult to manufacture a deep-drawn bushing with a very thin wall thickness, and its processability is poor. The magnetic path gap formed by the bushing thickness between the armature and the top cover due to process limitations seriously weakens the driving electromagnetic force of the fixed iron core on the armature.

[0004] In addition, for a large-flow normally open piston cooling control solenoid valve, the outer circle of the valve core and the axial through hole of the valve sleeve are used for sealing. If the elastic force of the spring is small, the thrust of the spring to push the armature and the valve core to reset is small. The clearance between the outer circle of the valve core and the axial through hole of the valve sleeve needs to be large enough to ensure the reliability of the spring to push the armature and the valve core to move. However, if the clearance between the outer circle of the valve core and the axial through hole of the valve sleeve is large, the sealing performance of the valve core to the oil outlet is poor.

[0005] In addition, in terms of noise, it is required that the noise of the piston cooling control solenoid valve is small enough. However, in current engine piston cooling control solenoid valves, the armature will collide with the fixed iron core when it is attracted, generating a large impact noise, and the armature will collide with the bushing when it resets, generating a large impact noise. Summary of the Invention

[0006] In view of the foregoing, the present invention aims to provide a normally open piston cooling control solenoid valve, which has any one or more of the following advantages: large flow rate, good processability, high reliability, and low noise.

[0007] The present invention discloses a normally open piston cooling control solenoid valve, which is characterized in that:

[0008] The normally open piston cooling control solenoid valve includes a coil, a bracket, a valve sleeve, a valve core, a spring, and a filter screen. The bracket is arranged between the coil and the valve sleeve. The bottom surface of the coil abuts against the top surface of the bracket, and the top surface of the valve sleeve abuts against the bottom surface of the bracket. The valve core is arranged inside the valve sleeve, and the spring is sleeved on the outer periphery of the valve core;

[0009] The normally open piston cooling control solenoid valve further includes an armature and a push rod arranged inside the coil. The push rod is located below the armature and above the valve core;

[0010] The valve sleeve is further provided with an internal axial through hole, an oil outlet hole communicating the internal axial through hole with the outside of the valve sleeve, and an oil inlet chamber. The oil inlet chamber is a cavity without components obstructing the flow of oil inside. The diameter of its minimum flow cross-section is equal to the aperture of the internal axial through hole, so as to maximize the size of the oil inlet flow hole. Maximizing the size of the oil inlet flow hole and having no components obstructing the flow of oil in the oil inlet chamber results in low flow resistance of the oil and a large flow rate of the oil flowing out;

[0011] After the oil enters the normally open piston cooling control solenoid valve, it is filtered by the filter screen and then flows out from the oil inlet chamber through the oil outlet hole;

[0012] When the coil is powered off, the spring pushes the valve core upward to keep the oil inlet chamber and the oil outlet hole in communication, making the solenoid valve normally open;

[0013] When the coil is powered on, the electromagnetic force generated by the coil drives the armature. The armature pushes the push rod and the valve core to move downward together to compress the spring, and the valve core moves downward to close the oil outlet hole.

[0014] Preferably,

[0015] A sunken hole is provided at the top of the valve sleeve, and a stepped sunken hole of the valve sleeve is provided at the bottom surface of the sunken hole at the top of the valve sleeve;

[0016] A valve core step is provided in the middle of the valve core axially. A root relief groove is provided at the root of the valve core step, and a valve core buffer ring is provided in the root relief groove. Among them, the valve core buffer ring is made of an elastic material and is used to block the impact of the valve core on the valve sleeve. The valve core buffer ring absorbs the movement impact of the valve core due to elastic deformation and suppresses the impact noise when the valve core seats;

[0017] The electromagnetic force generated after the coil is energized drives the armature. The armature pushes the push rod and the valve core to move downward together to compress the spring until the buffer ring in the root relief groove presses against the bottom surface of the stepped counterbore of the valve sleeve. At this time, the valve core blocks the oil outlet hole and closes the solenoid valve.

[0018] Preferably,

[0019] The normally open piston cooling control solenoid valve further includes a top cover, a bushing and a fixed iron core;

[0020] The top cover is arranged above the coil to cover the normally open piston cooling control solenoid valve. There is a top cover counterbore at the bottom of the top cover and a top cover stepped counterbore at the top;

[0021] The bushing is installed in the top cover counterbore. The bushing is a tubular body. The armature is installed in the inner hole of the bushing. The head of the armature protrudes from the top end of the bushing and extends into the top cover stepped counterbore;

[0022] The fixed iron core is installed in the bushing hole. There is a fixed iron core flange at the bottom of the fixed iron core. There is a gap δ1 between the top surface of the fixed iron core flange and the bottom surface of the bushing to prevent the bushing from being squeezed and deformed to jam the armature.

[0023] Preferably,

[0024] There is an armature counterbore at the top of the armature. An armature buffer pin is arranged in the armature counterbore. Among them, the armature buffer pin is made of elastic material and is used to block the impact of the armature on the top cover. The armature buffer pin absorbs the movement impact of the armature due to elastic deformation;

[0025] When the coil is de-energized, the spring pushes the valve core, the push rod, the armature and the armature buffer pin upward so that the top end of the armature buffer pin abuts against the bottom surface of the top cover stepped counterbore.

[0026] Preferably,

[0027] When the buffer ring presses against the bottom surface of the valve sleeve stepped counterbore, there is a minimum limit gap δ2 between the bottom surface of the armature and the top surface of the fixed iron core, so as to prevent the armature from being deformed due to hitting the fixed iron core during suction and getting stuck in the inner hole of the bushing, eliminate the impact noise between the armature and the fixed iron core, and when the armature disengages from the fixed iron core for reset after the coil is de-energized, suppress the adhesion resistance between the bottom surface of the armature and the top surface of the fixed iron core due to the viscosity of the oil, and improve the reliability of the armature and the valve core to reset and open the oil outlet hole.

[0028] Preferably,

[0029] The head of the armature protrudes from the top end of the bushing and extends into the top cover stepped counterbore;

[0030] A very small assembly gap is provided between the outer circle of the armature and the counterbore of the top cover, which reduces the magnetic resistance caused by the magnetic gap in the magnetic circuit and increases the electromagnetic driving force exerted by the fixed iron core on the armature after the coil is energized. Thus, the reliability of the electromagnetic driving force to drive the armature to push the valve core to move is improved.

[0031] The increase in the electromagnetic driving force correspondingly increases the elastic force of the spring. The increase in the electromagnetic driving force and the spring elastic force enables a smaller fit gap to be adopted between the outer circle of the valve core and the internal axial through-hole, ensuring the reliability of the valve core movement, and thus improving the sealing reliability of the valve core to the oil outlet hole of the valve sleeve.

[0032] Preferably,

[0033] A coil top counterbore is provided at the top of the coil, and a coil bottom counterbore is provided at the bottom. A coil top sealing ring is provided in the coil top counterbore.

[0034] Preferably,

[0035] A groove axially penetrating the push rod is provided on the push rod, and a central through-hole is provided on the bracket. Among them, the central through-hole of the bracket is sleeved on the outer circle of the fixed iron core flange;

[0036] The bottom end of the push rod passes through the axial through-hole of the fixed iron core and presses on the top surface of the valve core,

[0037] The spring is installed on the outer circle of the head of the valve core.

[0038] Preferably,

[0039] A spring seat flange integral with the valve core is provided at the top of the valve core.

[0040] Preferably,

[0041] A bracket upper sealing ring is provided in the pit formed by the outer circle of the fixed iron core flange and the coil bottom counterbore; a bracket lower sealing ring is provided in the pit formed by the outer circle of the fixed iron core flange and the valve sleeve top counterbore.

[0042] The present invention has the following beneficial effects:

[0043] The present invention relates to a normally open piston cooling control solenoid valve. After the oil enters the normally open piston cooling control solenoid valve, it is filtered by the filter screen and then flows out from the oil inlet cavity through the oil outlet hole. When the coil is de-energized, the spring pushes the valve core upward to keep the oil inlet cavity and the oil outlet hole in communication, making the solenoid valve normally open. The oil inlet cavity of the solenoid valve in this application is a cavity without components obstructing the oil flow inside, which results in small oil flow resistance and large oil flow rate when the oil flows out. Secondly, this solenoid valve is equipped with a buffer device to absorb shocks and reduce noise. In addition, this solenoid valve has small gaps set at some positions to improve the reliability of the solenoid valve, and the bushing structure adopted is simple and efficient.

[0044] Descriptions of directions such as "upper", "lower", "top", and "bottom" in this specification are for the directions of the structures in the drawings, and the same applies hereinafter. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention, and therefore should not be regarded as limiting the scope. For those of ordinary skill in the art, without creative efforts, other related drawings can also be obtained based on these drawings.

[0046] Figure 1 is a structural view of the open type piston cooling control solenoid valve of the present invention in the open state;

[0047] Figure 2 is a structural view of the open type piston cooling control solenoid valve of the present invention in the closed state;

[0048] Figure 3 is an external view of the coil of the open type piston cooling control solenoid valve of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0049] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. Usually, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0050] Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the claimed invention, but merely represents the selected embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts fall within the scope of protection of the present invention.

[0051] It should be noted that similar reference numerals and letters denote similar items in the following drawings. Therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings.

[0052] In the description of the present invention, it should be noted that if terms such as "upper", "lower", "inner", "outer", "parallel", "perpendicular", etc. are used to indicate the orientation or positional relationship, it is based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship in which the invention product is usually placed during use. This is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or component referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present invention.

[0053] In addition, if terms such as "first", "second", etc. are used only for distinguishing descriptions, they cannot be understood as indicating or implying relative importance.

[0054] It should be noted that, without conflict, the features in the embodiments of the present invention can be combined with each other.

[0055] The present invention will be further described below with reference to the drawings:

[0056] In one embodiment,

[0057] The present invention discloses a normally open piston cooling control solenoid valve, which is characterized in that:

[0058] The normally open piston cooling control solenoid valve includes (1), a bracket (10), a valve sleeve (13), a valve core (14), a spring (15) and a filter screen (17). The bracket (10) is arranged between the coil (1) and the valve sleeve (13). The bottom surface of the coil (1) abuts against the top surface of the bracket (10). The top surface of the valve sleeve (13) abuts against the bottom surface of the bracket (10). The valve core (14) is arranged inside the valve sleeve (13). The spring (15) is sleeved on the outer periphery of the valve core (14);

[0059] The valve sleeve (13) is further provided with an internal axial through hole (13-4), an oil outlet hole (13-5) communicating the internal axial through hole (13-4) with the outside of the valve sleeve (13), and an oil inlet cavity (13-6); the oil inlet cavity (13-6) is a cavity without components hindering the flow of oil inside. The minimum cross-sectional diameter of the oil flow hole is equal to the aperture of the internal axial through hole (13-4) to maximize the size of the oil inlet flow hole; maximizing the size of the oil inlet flow hole and having no components hindering the flow of oil in the oil inlet cavity results in low flow resistance of the oil and a large flow rate of the oil flowing out;

[0060] After the oil enters the normally open piston cooling control solenoid valve, it is filtered by the filter screen (17) and then flows out from the oil inlet cavity (13-6) through the oil outlet hole (13-5);

[0061] When the coil (1) is powered off, the spring (15) pushes the valve core (14) upward to keep the oil inlet cavity (13-6) and the oil outlet hole (13-5) in communication, making the solenoid valve normally open.

[0062] Through the above embodiments, this solenoid valve utilizes the change in electromagnetic force when the coil is energized and de-energized. The electromagnetic force causes the spool to move up and down, realizing the opening and closing of the solenoid valve. The oil inlet cavity of this normally open piston cooling control solenoid valve is a cavity without components obstructing the flow of oil, which results in low flow resistance of the oil in this solenoid valve, large oil outflow, and beneficial effects such as high reliability.

[0063] In another preferred embodiment,

[0064] A valve sleeve top counterbore (13-2) is provided at the top of the valve sleeve (13), and a valve sleeve stepped counterbore (13-3) is provided on the bottom surface of the valve sleeve top counterbore (13-2);

[0065] A spool step (14-2) is provided in the middle of the spool (14) axially. A root relief groove (14-3) is provided at the root of the spool step (14-2), and a spool buffer ring (16) is provided in the root relief groove (14-3); wherein, the spool buffer ring (16) is made of an elastic material and is used to block the impact of the spool (14) on the valve sleeve (13). The spool buffer ring (16) absorbs the movement impact of the spool (14) due to elastic deformation and suppresses the impact noise when the spool (14) seats;

[0066] After the coil (1) is energized, the electromagnetic force generated drives the armature (3). The armature (3) pushes the push rod (7) and the spool (14) to move downward together and compress the spring (15) until the buffer ring (16) in the root relief groove (14-3) presses on the bottom surface of the valve sleeve stepped counterbore (13-3). At this time, the spool (14) blocks the oil outlet hole (13-5) to close the solenoid valve.

[0067] In another preferred embodiment,

[0068] The normally open piston cooling control solenoid valve further includes a top cover (2), a bushing (5) and a fixed iron core (9);

[0069] The top cover (2) is arranged above the coil (1) to cover the normally open piston cooling control solenoid valve. A top cover counterbore (2-1) is provided at the bottom of the top cover (2), and a top cover stepped counterbore (2-2) is provided at the top;

[0070] The bushing (5) is installed in the top cover counterbore (2-1). The bushing (5) is a tubular body. The armature (3) is installed in the inner hole of the bushing (5). The head of the armature (3) protrudes from the top end of the bushing (5) and extends into the top cover stepped counterbore (2-2);

[0071] The stationary iron core (9) is installed in the hole of the bushing (5). A stationary iron core flange (9-1) is provided at the bottom of the stationary iron core (9). A gap δ1 is provided between the top surface of the stationary iron core flange (9-1) and the bottom surface of the bushing (5) to prevent the bushing (5) from being squeezed and deformed to jam the armature (3).

[0072] In another preferred embodiment,

[0073] An armature counterbore (3-1) is provided at the top of the armature (3). An armature buffer pin (4) is arranged in the armature counterbore (3-1). Among them, the armature buffer pin (4) is made of an elastic material and is used to block the impact of the armature (3) on the top cover (2). The armature buffer pin (4) absorbs the movement impact of the armature (3) due to elastic deformation;

[0074] When the coil (1) is powered off, the spring (15) pushes the valve core (14), the push rod (7), the armature (3) and the armature buffer pin (4) upward so that the top end of the armature buffer pin (4) abuts against the bottom surface of the stepped counterbore (2-2) of the top cover.

[0075] In another preferred embodiment,

[0076] When the buffer ring (16) presses against the bottom surface of the stepped counterbore (13-3) of the valve sleeve, a minimum limit gap δ2 is provided between the bottom surface of the armature (3) and the top surface of the stationary iron core (9) to prevent the armature (3) from being deformed due to impact on the stationary iron core (9) during suction and getting stuck in the inner hole of the bushing (5), eliminating the impact noise between the armature (3) and the stationary iron core (9). And after the coil (1) is powered off and the armature (3) disengages from the stationary iron core (9) for reset, the adhesion resistance between the bottom surface of the armature (3) and the top surface of the stationary iron core (9) due to the viscosity of the oil is inhibited, improving the reliability of the armature (3) and the valve core (14) to reset and open the oil outlet hole (13-5).

[0077] In another preferred embodiment,

[0078] The head of the armature (3) protrudes from the top end of the bushing (5) and extends into the stepped counterbore (2-2) of the top cover;

[0079] An extremely small assembly gap is provided between the outer circle of the armature (3) and the counterbore (2-1) of the top cover, reducing the magnetic resistance caused by the magnetic gap of the magnetic circuit, increasing the electromagnetic driving force of the stationary iron core (9) on the armature (3) after the coil (1) is powered on, and thus improving the reliability of the electromagnetic driving force to drive the armature (3) to push the valve core (14) to move;

[0080] The increase in the electromagnetic driving force correspondingly increases the elastic force of the spring (15). The increase in the electromagnetic driving force and the elastic force of the spring (15) enables a smaller fitting clearance to be adopted between the outer circle of the valve core (14) and the internal axial through hole (13-4), ensuring the reliability of the movement of the valve core (14), and thus improving the sealing reliability of the valve core (14) for the oil outlet hole (13-5) of the valve sleeve (13).

[0081] In another preferred embodiment,

[0082] A coil top counterbore (1-1) is provided at the top of the coil (1), and a coil bottom counterbore (1-2) is provided at the bottom. A coil top sealing ring (6) is provided in the coil top counterbore (1-1).

[0083] In another preferred embodiment,

[0084] A groove (7-1) axially penetrating the push rod (7) is provided on the push rod (7), and an axial through hole is provided on the bracket (10). Among them, the axial through hole of the bracket is sleeved on the outer circle of the fixed iron core flange (9-1);

[0085] The bottom end of the push rod (7) passes through the axial through hole of the fixed iron core (9) and presses on the top surface of the valve core (14),

[0086] The spring (15) is installed on the outer circle of the head of the valve core (14).

[0087] In another preferred embodiment,

[0088] A spring seat flange (14-1) integral with the valve core (14) is provided at the top of the valve core (14).

[0089] In another preferred embodiment,

[0090] A bracket upper sealing ring (11) is provided in the pit formed by the outer circle of the fixed iron core flange (9-1) and the coil bottom counterbore (1-2); a bracket lower sealing ring (12) is provided in the pit formed by the outer circle of the fixed iron core flange (9-1) and the valve sleeve top counterbore (13-2).

[0091] In another preferred embodiment,

[0092] A normally open piston cooling control solenoid valve is disclosed. The normally open piston cooling control solenoid valve includes a coil (1), a bracket (10), a valve sleeve (13), a valve core (14), a spring (15), and a filter screen (17). The bracket (10) is provided between the coil (1) and the valve sleeve (13). The bottom surface of the coil (1) abuts against the top surface of the bracket (10), the top surface of the valve sleeve (13) abuts against the bottom surface of the bracket (10), the valve core (14) is arranged inside the valve sleeve (13), and the spring (15) is sleeved on the outer periphery of the valve core (14);

[0093] The normally open type piston cooling control solenoid valve further includes an armature (3) and a push rod (7) disposed inside the coil (1). The push rod (7) is located below the armature (3) and above the valve core (14).

[0094] The valve sleeve (13) is further provided with an internal axial through hole (13-4), an oil outlet hole (13-5) communicating the internal axial through hole (13-4) with the outside of the valve sleeve (13), and an oil inlet cavity (13-6). The oil inlet cavity (13-6) is a cavity of a component without obstacles to the flow of oil inside. The diameter of its minimum flow cross-section is equal to the diameter of the internal axial through hole (13-4) to maximize the size of the oil inlet flow hole. Maximizing the size of the oil inlet flow hole and having no component obstructing the flow of oil in the oil inlet cavity results in low flow resistance of the oil and a large flow rate of the oil flowing out.

[0095] After the oil enters the normally open type piston cooling control solenoid valve, it is filtered by the filter screen (17) and then flows out from the oil inlet cavity (13-6) through the oil outlet hole (13-5).

[0096] When the coil (1) is powered off, the spring (15) pushes the valve core (14) upward to keep the oil inlet cavity (13-6) and the oil outlet hole (13-5) in communication, making the solenoid valve normally open.

[0097] When the coil (1) is powered on, the electromagnetic force generated by the coil (1) drives the armature (3). The armature (3) pushes the push rod (7) and the valve core (14) to move downward together to compress the spring (15), and the valve core (14) moves downward to close the oil outlet hole (13-5).

[0098] The flanging at the oil inlet end of the valve sleeve (13) rivets and clamps the filter screen (17).

[0099] So far, the working principle of the solenoid valve of the present invention can be understood:

[0100] When the coil (1) is powered off, the spring (15) pushes the valve core (14) and the push rod (7), driving the armature (3) to move upward to inhibit the back pressure resistance at both ends of the armature (3). The cavity at the top of the valve core (14) is communicated with the cavity at the bottom of the valve core (14) through the push rod (7) and the valve core (14) to inhibit the back pressure resistance at both ends of the valve core (14). The spring (15) pushes the valve core (14) upward to keep the oil inlet cavity (13-6) of the valve sleeve (13) and the oil outlet hole (13-5) in communication, making the piston cooling control solenoid valve normally open. The inlet oil is filtered by the filter screen (17) and then flows out from the oil inlet cavity (13-6) in the valve sleeve (13) through the oil outlet hole (13-5). When the coil (1) is powered on, the magnetic circuit generates an electromagnetic force to drive the armature (3) to drive the push rod (7) and the valve core (14) to move downward together to compress the spring (15) until the valve core (14) blocks the oil outlet hole (13-5) of the valve sleeve (13) to close the solenoid valve.

[0101] It can be understood that the most crucial point of the above embodiments lies in:

[0102] The oil inlet cavity of the solenoid valve is a cavity without components obstructing the flow of oil inside. The size of the oil inlet flow hole is maximized and there are no components obstructing the flow of oil in the oil inlet cavity, resulting in a small flow resistance of the oil and a large flow rate of the oil flowing out. In addition, the communication between the cavities at the upper and lower ends of the armature (3) suppresses the backpressure resistance during the movement of the armature (3), the communication between the cavities at the upper and lower ends of the valve core (14) suppresses the backpressure resistance during the movement of the valve core (14), reduces the magnetic reluctance of the magnetic circuit and increases the electromagnetic driving force, thereby increasing the elastic force for the spring (15) to reset, making the movement of the armature (3) and the valve core (14) highly reliable. The increase in the electromagnetic driving force and the elastic force for the spring (15) to reset further reduces the clearance between the valve core (14) and the valve hole of the valve sleeve (13), improving the reliability of the valve core (14) to seal the oil outlet hole (13-5) of the valve sleeve (13). This makes the solenoid valve have beneficial effects such as high reliability.

[0103] In another preferred embodiment,

[0104] A valve sleeve top counterbore (13-2) is provided at the top of the valve sleeve (13), and a valve sleeve stepped counterbore (13-3) is provided on the bottom surface of the valve sleeve top counterbore (13-2);

[0105] A valve core step (14-2) is provided in the middle of the valve core (14) axially, a root relief groove (14-3) is provided at the root of the valve core step (14-2), and a valve core buffer ring (16) is provided in the root relief groove (14-3); wherein, the valve core buffer ring (16) is made of an elastic material and is used to block the impact of the valve core (14) on the valve sleeve (13). The valve core buffer ring (16) absorbs the movement impact of the valve core (14) due to elastic deformation and suppresses the impact noise when the valve core (14) seats;

[0106] After the coil (1) is energized, the electromagnetic force generated drives the armature (3), and the armature (3) pushes the push rod (7) and the valve core (14) to move downward together to compress the spring (15) until the buffer ring (16) in the root relief groove (14-3) presses on the bottom surface of the valve sleeve stepped counterbore (13-3). At this time, the valve core (14) blocks the oil outlet hole (13-5) to close the solenoid valve;

[0107] The normally open type piston cooling control solenoid valve further includes a top cover (2). A armature counterbore (3-1) is provided at the top of the armature (3), and an armature buffer pin (4) is provided in the armature counterbore (3-1). Among them, the armature buffer pin (4) is made of an elastic material and is used to block the impact of the armature (3) on the top cover (2). The armature buffer pin (4) absorbs the movement impact of the armature (3) due to elastic deformation;

[0108] When the coil (1) is powered off, the spring (15) pushes the spool (14), push rod (7), armature (3) and armature buffer pin (4) upward, so that the top end of the armature buffer pin (4) abuts against the bottom surface of the stepped counterbore (2-2) of the top cover.

[0109] In the above embodiment, since both the buffer ring (16) and the armature buffer pin (4) are made of elastic materials, the buffer ring (16) blocks the impact of the spool (14) on the valve sleeve (13) and suppresses the impact noise of the spool (14) on the valve sleeve (13), while the armature buffer pin (4) absorbs the movement impact of the armature (3) and suppresses the impact noise during the reset of the armature (3), blocks the impact of the armature (3) on the top cover (2) and suppresses the impact noise of the armature (3) on the top cover (2), making the normally open piston cooling control solenoid valve have a lower operating noise.

[0110] In another preferred embodiment,

[0111] The normally open piston cooling control solenoid valve further includes a top cover (2), a bushing (5) and a fixed iron core (9);

[0112] The top cover (2) is arranged above the coil (1) to cover the normally open piston cooling control solenoid valve. The bottom of the top cover (2) is provided with a top cover counterbore (2-1), and the top is provided with a stepped counterbore (2-2) of the top cover;

[0113] The bushing (5) is installed in the top cover counterbore (2-1). The bushing (5) is a tubular body. The armature (3) is installed in the inner hole of the bushing (5), and the head of the armature (3) protrudes from the top end of the bushing (5) and extends into the stepped counterbore (2-2) of the top cover;

[0114] The fixed iron core (9) is installed in the hole of the bushing (5). A fixed iron core flange (9-1) is provided at the bottom of the fixed iron core (9). A gap δ1 is provided between the top surface of the fixed iron core flange (9-1) and the bottom surface of the bushing (5) to prevent the bushing (5) from being squeezed and deformed to jam the armature (3).

[0115] When the buffer ring (16) presses against the bottom surface of the stepped counterbore (13-3) of the valve sleeve, a minimum limit gap δ2 is provided between the bottom surface of the armature (3) and the top surface of the fixed iron core (9) to prevent the armature (3) from being deformed due to hitting the fixed iron core (9) during suction and getting jammed in the inner hole of the bushing (5), eliminate the impact noise between the armature (3) and the fixed iron core (9), and when the coil (1) is powered off and the armature (3) disengages from the fixed iron core (9) for reset, suppress the adhesion resistance existing between the bottom surface of the armature (3) and the top surface of the fixed iron core (9) due to the viscosity of the oil, and improve the reliability of the armature (3) and the spool (14) to reset and open the oil outlet hole (13-5).

[0116] In the above embodiment, the bushing (5) is a tubular body with a simple structure, and the required length can be cut from the raw material pipe fitting, which is simpler and more efficient than the existing process of using multiple progressive dies for multiple stretching and forming of the bushing. The outer circle of the armature (3) and the counterbore at the bottom of the top cover (2) mating with it can obtain dimensions with high precision by using conventional turning and drilling processes. The high dimensional precision enables a small clearance between the outer circle of the armature (3) and the counterbore at the bottom of the mating top cover (2) that does not interfere with the flexible movement of the armature (3), thereby significantly reducing the magnetic resistance of the magnetic circuit at this location. In addition, when the coil (1) is energized to drive the armature (3) to push the push rod (7) and the valve core (14) to move downward together to compress the spring (15), the gap δ1 provided between the top surface of the fixed iron core flange (9-1) and the bottom surface of the bushing (5) and the minimum limit gap δ2 provided between the bottom surface of the armature (3) and the top surface of the fixed iron core (9) can not only effectively avoid the deformation of the bushing (5), but also suppress noise, thereby significantly improving the stability of the solenoid valve.

[0117] In another preferred embodiment,

[0118] The head of the armature (3) protrudes from the top end of the bushing (5) and extends into the stepped counterbore (2-2) of the top cover;

[0119] An extremely small assembly clearance is provided between the outer circle of the armature (3) and the counterbore (2-1) of the top cover, which reduces the magnetic resistance caused by the magnetic gap of the magnetic circuit and improves the electromagnetic driving force of the fixed iron core (9) on the armature (3) when the coil (1) is energized, thereby improving the reliability of the electromagnetic driving force to drive the armature (3) to push the valve core (14) to move;

[0120] The increase in the electromagnetic driving force correspondingly increases the elastic force of the spring (15). The increase in the electromagnetic driving force and the elastic force of the spring (15) enables a smaller clearance to be adopted between the outer circle of the valve core (14) and the internal axial through hole (13-4), ensuring the reliability of the movement of the valve core (14), and thus improving the sealing reliability of the valve core (14) for the oil outlet hole (13-5) of the valve sleeve (13).

[0121] A coil top counterbore (1-1) is provided at the top of the coil (1), and a coil bottom counterbore (1-2) is provided at the bottom. A coil top sealing ring (6) is provided in the coil top counterbore (1-1).

[0122] In the above embodiment, the processability of the outer circle of the armature (3) and the counterbore at the bottom of the top cover (2) is good, enabling a small assembly clearance and significantly reducing the magnetic resistance caused by the magnetic gap of the magnetic circuit, and greatly improving the electromagnetic driving force of the fixed iron core (9) on the armature (3) when the coil (1) is energized. The increase in the electromagnetic driving force correspondingly increases the elastic force of the spring (15), thereby improving the sealing reliability of the valve core (14) for the oil outlet hole (13-5) of the valve sleeve (13) and improving the stability of the solenoid valve.

[0123] In another preferred embodiment,

[0124] A groove (7-1) axially penetrating through the push rod (7) is provided on the push rod (7), and an axial center through hole is provided on the bracket (10). Among them, the axial center through hole of the bracket is sleeved on the outer circle of the fixed iron core flange (9-1);

[0125] The bottom end of the push rod (7) passes through the axial through hole of the fixed iron core (9) and presses on the top surface of the valve core (14),

[0126] The spring (15) is installed on the outer circle of the head of the valve core (14).

[0127] A spring seat flange (14-1) integral with the valve core (14) is provided on the top of the valve core (14).

[0128] A bracket upper sealing ring (11) is arranged in the pit formed by the outer circle of the fixed iron core flange (9-1) and the bottom sunken hole (1-2) of the coil; a bracket lower sealing ring (12) is arranged in the pit formed by the outer circle of the fixed iron core flange (9-1) and the top sunken hole (13-2) of the valve sleeve.

[0129] The top of the coil housing (8) is provided with a top notch (8-1) and a top flange (8-2), and the bottom of the coil housing (8) is provided with a bottom notch (8-3) and a bottom flange (8-4).

[0130] In another preferred embodiment,

[0131] A normally open piston cooling control solenoid valve, which comprises a coil (1), a top cover (2), an armature (3), an armature buffer pin (4), a bushing (5), a coil top sealing ring (6), a push rod (7), a coil housing (8), a fixed iron core (9), a bracket (10), an upper sealing ring on the bracket (11), a lower sealing ring on the bracket (12), a valve sleeve (13), a valve core (14), a spring (15), a valve core buffer ring (16) and a filter screen (17). A counterbore (1-1) is provided at the top of the coil (1), and a counterbore (1-2) is provided at the bottom of the coil (1). The coil (1) is installed in the coil housing (8). A top notch (8-1) and a top flanging (8-2) are provided at the top of the coil housing (8), and a bottom notch (8-3) and a bottom flanging (8-4) are provided at the bottom of the coil housing (8). The top cover (2) is installed in the inner hole of the coil housing (8) and the top notch (8-1) and is riveted and clamped by the top flanging (8-2) of the coil housing (8). A counterbore (2-1) is provided at the bottom of the top cover (2), and a stepped counterbore (2-2) is further provided on the bottom surface of the counterbore (2-1) at the bottom of the top cover (2). The bushing (5) is installed in the counterbore (2-1) at the bottom of the top cover (2). The bushing (5) is a tubular body. The armature (3) is installed in the inner hole of the bushing (5). The head of the armature (3) protrudes from the top end of the bushing (5) and extends into the stepped counterbore (2-2) on the bottom surface of the counterbore (2-1) at the bottom of the top cover (2). A counterbore (3-1) is provided at the top of the armature (3), and an axial through hole (3-2) is provided inside the armature (3). An armature buffer pin (4) is provided in the counterbore (3-1) at the top of the armature (3). The armature buffer pin (4) is made of an elastic material. A coil top sealing ring (6) is provided in the counterbore (1-1) at the top of the coil (1). A push rod (7) is provided below the armature (3). A groove (7-1) axially penetrating the push rod (7) is provided on the push rod (7). The fixed iron core (9) is also installed in the hole of the bushing (5). A flange (9-1) is provided at the bottom of the fixed iron core (9). The bracket (10) is installed at the bottom of the coil housing (8). A through hole is provided at the axis of the bracket (10) in the coil housing (8). The axial through hole on the bracket (10) is sleeved on the outer circle of the flange (9-1) at the bottom of the fixed iron core (9). An upper sealing ring on the bracket (11) is provided in the pit formed by the outer circle of the flange (9-1) at the bottom of the fixed iron core (9) and the counterbore (1-2) at the bottom of the coil (1). The top surface of the valve sleeve (13) abuts against the bottom surface of the bracket (10). A flange (13-1) is provided at the top of the valve sleeve (13). The bottom flanging (8-4) of the coil housing (8) rivets and clamps the flange (13-1) at the top of the valve sleeve (13). A counterbore (13-2) is provided at the top of the valve sleeve (13). A lower sealing ring on the bracket (12) is provided in the pit formed by the outer circle of the flange (9-1) at the bottom of the fixed iron core (9) and the counterbore (13-2) at the top of the valve sleeve (13). A stepped counterbore (13-3) is further provided on the bottom surface of the counterbore (13-2) at the top of the valve sleeve (13).An axial through-hole (13-4) is provided inside the valve sleeve (13). An oil outlet hole (13-5) is provided on the valve sleeve (13) to connect the internal axial through-hole (13-4) with the outside of the valve sleeve (13). An oil inlet cavity (13-6) is provided inside the valve sleeve (13). The oil inlet cavity (13-6) is a cavity without components obstructing the oil flow inside. The diameter of the minimum flow-through cross-section of the oil inlet cavity (13-6) is equal to the aperture of the axial through-hole (13-4) of the valve sleeve (13) to maximize the size of the oil inlet flow-through hole. The flanging at the oil inlet end of the valve sleeve (13) rivets and clamps the filter screen (17). The valve core (14) is installed in the axial through-hole (13-4) inside the valve sleeve (13). The bottom end of the push rod (7) passes through the axial through-hole of the fixed iron core (9) and presses on the top surface of the valve core (14). A spring seat flange (14-1) integrated with the valve core (14) is provided at the top of the valve core (14). A step (14-2) is provided in the middle part of the valve core (14) axially. A relief groove (14-3) is provided at the root of the step (14-2) in the middle part of the valve core (14) axially. An axial through-hole (14-4) is provided inside the valve core (14). The spring (15) is installed on the outer circle of the head of the valve core (14). The top surface of the spring (15) abuts against the bottom surface of the spring seat flange (14-1) at the top of the valve core (14). A buffer ring (16) is provided in the relief groove (14-3) at the root of the step (14-2) in the middle part of the valve core (14) axially. The buffer ring (16) is made of elastic material. When the coil (1) is powered off, the spring (15) pushes the valve core (14), the push rod (7), the armature (3), and the armature buffer pin (4) mounted on the armature (3) upward, so that the top end of the armature buffer pin (4) abuts against the bottom surface of the counterbore (2-1) at the bottom of the top cover (2). The armature buffer pin (4) blocks the impact of the top surface of the armature (3) on the bottom surface of the counterbore (2-1) at the bottom of the top cover (2), preventing the top of the armature (3) from being deformed by the impact and getting stuck in the counterbore (2-1) at the bottom of the top cover (2). The armature buffer pin (4) elastically deforms to absorb the movement impact of the armature (3) and suppresses the impact noise when the armature (3) resets. The cavity at the top of the armature (3) is connected to the cavity at the bottom of the armature (3) through the axial through-hole (3-2) inside the armature (3) and the groove (7-1) on the push rod (7) to suppress the backpressure resistance at both the upper and lower ends of the armature (3). The cavity at the top of the valve core (14) is connected to the cavity at the bottom of the valve core (14) through the groove (7-1) on the push rod (7) and the axial through-hole (14-4) inside the valve core (14) to suppress the backpressure resistance at both the upper and lower ends of the valve core (14). The spring (15) pushes the valve core (14) upward to keep the oil inlet cavity (13-6) of the valve sleeve (13) connected to the oil outlet hole (13-5), making the piston cooling control solenoid valve normally open. The oil enters through the filter screen (17) and flows out from the oil inlet cavity (13-6) inside the valve sleeve (13) through the oil outlet hole (13-5).The head of the armature (3) protrudes beyond the top end of the bushing (5) and extends into the stepped counterbore (2-2) on the bottom surface of the counterbore (2-1) at the bottom of the top cover (2), so that there is no component blocking the magnetic path in the magnetic path from the armature (3) to the top cover (2). The processability of the outer circle of the armature (3) and the counterbore at the bottom of the top cover (2) is good, resulting in a small assembly gap and significantly reducing the magnetic resistance caused by the magnetic gap in the magnetic path. This greatly improves the electromagnetic driving force exerted by the fixed iron core (9) on the armature (3) after the coil (1) is energized, thereby enhancing the reliability of the electromagnetic driving force to drive the armature (3) to push the valve core (14) to move. With the increase of the electromagnetic driving force, the elastic force of the spring (15) is correspondingly increased. The increase of the electromagnetic driving force and the elastic force of the spring (15) enables a smaller fit gap to be adopted between the outer circle of the valve core (14) and the axial through hole (13-4) of the valve sleeve (13) while still ensuring the reliability of the movement of the valve core (14). Thus, the sealing reliability of the valve core (14) for the oil outlet hole (13-5) of the valve sleeve (13) is improved. The size of the oil inlet flow-through hole is maximized and there is no component obstructing the flow of the oil in the oil inlet chamber. The small flow resistance of the oil allows a large flow rate of the oil to flow out. The bushing (5) is a simple tubular body, and the outer circle of the armature (3) and the counterbore at the bottom of the top cover (2) that mates with it are also easy to machine, with good processability. The communication of the cavities at the upper and lower ends of the armature (3) suppresses the backpressure resistance during the movement of the armature (3), the communication of the cavities at the upper and lower ends of the valve core (14) suppresses the backpressure resistance during the movement of the valve core (14), reduces the magnetic resistance of the magnetic path and increases the electromagnetic driving force, and further increases the elastic force of the spring (15) for resetting, enabling the movements of the armature (3) and the valve core (14) to have high reliability. The increase of the electromagnetic driving force and the elastic force of the spring (15) for resetting further reduces the fit gap between the valve core (14) and the valve hole of the valve sleeve (13), thus improving the sealing reliability of the valve core (14) for the oil outlet hole (13-5) of the valve sleeve (13). The armature buffer pin (4) blocks the impact of the armature (3) on the top cover (2) and suppresses the impact noise of the armature (3) on the top cover (2), making the normally open type piston cooling control solenoid valve have a lower operating noise.

[0132] A gap δ1 is provided between the top surface of the bottom flange (9-1) of the stationary iron core (9) and the bottom surface of the bushing (5) to prevent the bushing (5) from being deformed by extrusion. When the coil (1) is energized, an electromagnetic force is generated in the magnetic circuit to drive the armature (3) to drive the push rod (7) and the valve core (14) to move downward together to compress the spring (15) until the buffer ring (16) in the relief groove (14-3) of the middle step (14-2) of the valve core (14) presses against the bottom surface of the stepped counterbore (13-3) in the top counterbore (13-2) of the valve sleeve (13). At this time, the valve core (14) blocks the oil outlet hole (13-5) of the valve sleeve (13) to close the solenoid valve. The buffer ring (16) blocks the impact of the middle step (14-2) of the valve core (14) on the bottom surface of the stepped counterbore (13-3) in the top counterbore (13-2) of the valve sleeve (13). The buffer ring (16) elastically deforms to absorb the movement impact of the valve core (14) and suppresses the impact noise when the valve core (14) seats. When the buffer ring (16) presses against the bottom surface of the stepped counterbore (13-3) in the top counterbore (13-2) of the valve sleeve (13), a minimum limit gap δ2 is provided between the bottom surface of the armature (3) and the top surface of the stationary iron core (9) to prevent the armature (3) from hitting the stationary iron core (9) during suction, avoid deformation of the bottom of the armature (3) due to hitting the stationary iron core (9) and getting stuck in the inner hole of the bushing (5), and eliminate the impact noise between the armature (3) and the stationary iron core (9). It suppresses the adhesion resistance existing between the bottom surface of the armature (3) and the top surface of the stationary iron core (9) due to the viscosity of the oil when the armature (3) disengages from the stationary iron core (9) and resets after the coil (1) is de-energized, and improves the reliability of the armature (3) and the valve core (14) to reset and open the oil outlet hole (13-5) of the valve sleeve (13). A gap δ1 is provided between the top surface of the bottom flange (9-1) of the stationary iron core (9) and the bottom surface of the bushing (5) to prevent the bushing (5) from being deformed by extrusion. The armature buffer pin (4) blocks the impact of the armature (3) on the top cover (2) to avoid deformation of the top of the armature (3) due to impact and getting stuck in the counterbore (2-1) of the top cover (2). A minimum limit gap δ2 is provided between the bottom surface of the armature (3) and the top surface of the stationary iron core (9) to avoid deformation of the bottom of the armature (3) due to hitting the stationary iron core (9) and getting stuck in the inner hole of the bushing (5) and suppress the adhesion resistance between the armature (3) and the stationary iron core (9), making the movement of the armature (3) and the valve core (14) highly reliable. The buffer ring (16) blocks the impact of the valve core (14) on the valve sleeve (13) and suppresses the impact noise of the valve core (14) on the valve sleeve (13). A minimum limit gap δ2 is provided between the armature (3) and the stationary iron core (9) to block the impact of the armature (3) on the stationary iron core (9) and eliminate the impact noise of the armature (3) on the stationary iron core (9), making the normally open piston cooling control solenoid valve have a lower operating noise.

[0133] It is obvious to those skilled in the art that the present invention is not limited to the details of the above-described exemplary embodiments, and that the present invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the present invention. Therefore, in any regard, the embodiments should be regarded as exemplary and non-limiting. The scope of the present invention is defined by the appended claims rather than the above description. Therefore, all changes falling within the meaning and scope of the equivalent elements of the claims are intended to be embraced within the present invention. Any reference signs in the claims should not be construed as limiting the claims involved.

Claims

1. A normally open piston cooling control solenoid valve, characterized in that: The normally open piston cooling control solenoid valve includes a coil (1), a bracket (10), a valve sleeve (13), a valve core (14), a spring (15) and a filter screen (17). The bracket (10) is arranged between the coil (1) and the valve sleeve (13). The bottom surface of the coil (1) abuts against the top surface of the bracket (10). The top surface of the valve sleeve (13) abuts against the bottom surface of the bracket (10). The valve core (14) is arranged inside the valve sleeve (13). The spring (15) is sleeved on the outer periphery of the valve core (14); The normally open piston cooling control solenoid valve further includes an armature (3) and a push rod (7) arranged inside the coil (1). The push rod (7) is located below the armature (3) and above the valve core (14); The valve sleeve (13) is further provided with an internal axial through hole (13-4), an oil outlet hole (13-5) communicating the internal axial through hole (13-4) with the outside of the valve sleeve (13), and an oil inlet cavity (13-6); The oil inlet cavity (13-6) is a cavity of a member without obstacles to the flow of oil. The minimum cross-sectional diameter of its flow passage is equal to the aperture of the internal axial through hole (13-4) to maximize the size of the oil inlet flow passage hole; Maximizing the size of the oil inlet flow passage hole and having no member obstructing the flow of oil in the oil inlet cavity results in low flow resistance of the oil and a large flow rate of the oil flowing out; After the oil enters the normally open piston cooling control solenoid valve, it is filtered by the filter screen (17) and then flows out from the oil inlet cavity (13-6) through the oil outlet hole (13-5); When the coil (1) is powered off, the spring (15) pushes the valve core (14) upward to keep the oil inlet cavity (13-6) and the oil outlet hole (13-5) in communication, making the solenoid valve normally open; When the coil (1) is powered on, the electromagnetic force generated by the coil (1) drives the armature (3). The armature (3) pushes the push rod (7) and the valve core (14) to move downward together to compress the spring (15). The valve core (14) moves downward to close the oil outlet hole (13-5).

2. A normally open piston cooling control solenoid valve according to claim 1, characterized in that: The top of the valve sleeve (13) is provided with a valve sleeve top counterbore (13-2), and the bottom surface of the valve sleeve top counterbore (13-2) is provided with a valve sleeve stepped counterbore (13-3); The middle part of the valve core (14) in the axial direction is provided with a valve core step (14-2). The root of the valve core step (14-2) is provided with a root relief groove (14-3). A valve core buffer ring (16) is arranged in the root relief groove (14-3); Among them, the valve core buffer ring (16) is made of an elastic material and is used to block the impact of the valve core (14) on the valve sleeve (13). The valve core buffer ring (16) absorbs the movement impact of the valve core (14) due to elastic deformation and suppresses the impact noise when the valve core (14) seats; After the coil (1) is energized, the electromagnetic force generated drives the armature (3). The armature (3) pushes the push rod (7) and the valve core (14) to move downward together to compress the spring (15) until the buffer ring (16) in the root relief groove (14-3) presses against the bottom surface of the valve sleeve stepped counterbore (13-3). At this time, the valve core (14) blocks the oil outlet hole (13-5) to close the solenoid valve.

3. The normally open piston cooling control solenoid valve according to claim 2, characterized in that: The normally open piston cooling control solenoid valve further includes a top cover (2), a bushing (5), and a fixed iron core (9); The top cover (2) is arranged above the coil (1) to cover the normally open piston cooling control solenoid valve. There is a top cover counterbore (2-1) at the bottom of the top cover (2) and a top cover stepped counterbore (2-2) at the top; The bushing (5) is installed in the top cover counterbore (2-1). The bushing (5) is a tubular body. The armature (3) is installed in the inner hole of the bushing (5). The head of the armature (3) protrudes from the top end of the bushing (5) and extends into the top cover stepped counterbore (2-2); The fixed iron core (9) is installed in the hole of the bushing (5). There is a fixed iron core flange (9-1) at the bottom of the fixed iron core (9). There is a gap δ1 between the top surface of the fixed iron core flange (9-1) and the bottom surface of the bushing (5) to prevent the bushing (5) from being squeezed and deformed to jam the armature (3).

4. The normally open piston cooling control solenoid valve according to claim 3, characterized in that: There is an armature counterbore (3-1) at the top of the armature (3). An armature buffer pin (4) is arranged in the armature counterbore (3-1). Among them, the armature buffer pin (4) is made of elastic material and is used to block the impact of the armature (3) on the top cover (2). The armature buffer pin (4) absorbs the movement impact of the armature (3) due to elastic deformation; When the coil (1) is de-energized, the spring (15) pushes the valve core (14), the push rod (7), the armature (3), and the armature buffer pin (4) upward so that the top end of the armature buffer pin (4) abuts against the bottom surface of the top cover stepped counterbore (2-2).

5. The normally open piston cooling control solenoid valve according to claim 3, characterized in that: When the buffer ring (16) presses against the bottom surface of the valve sleeve stepped counterbore (13-3), there is a minimum limit gap δ2 between the bottom surface of the armature (3) and the top surface of the fixed iron core (9) to prevent the armature (3) from being deformed and jammed in the inner hole of the bushing (5) due to hitting the fixed iron core (9) during suction, eliminate the impact noise between the armature (3) and the fixed iron core (9), and when the coil (1) is de-energized and the armature (3) disengages from the fixed iron core (9) for resetting, suppress the adhesion resistance between the bottom surface of the armature (3) and the top surface of the fixed iron core (9) due to the viscosity of the oil, and improve the reliability of the armature (3) and the valve core (14) to reset and open the oil outlet hole (13-5).

6. The normally open piston cooling control solenoid valve according to claim 3, characterized in that: The head of the armature (3) protrudes from the top end of the bushing (5) and extends into the top cover stepped counterbore (2-2); A very small assembly clearance is provided between the outer circle of the armature (3) and the counterbore of the top cover (2-1), which reduces the magnetic resistance caused by the magnetic gap of the magnetic circuit and increases the electromagnetic driving force exerted by the fixed iron core (9) on the armature (3) after the coil (1) is energized. Thus, the reliability of the electromagnetic driving force to drive the armature (3) to push the valve core (14) to move is improved; The increase in the electromagnetic driving force correspondingly increases the elastic force of the spring (15). The increase in the electromagnetic driving force and the elastic force of the spring (15) enables a smaller fit clearance to be adopted between the outer circle of the valve core (14) and the internal axial through hole (13-4), ensuring the reliability of the movement of the valve core (14). Thus, the sealing reliability of the valve core (14) for the oil outlet hole (13-5) of the valve sleeve (13) is improved.

7. A normally open piston cooling control solenoid valve according to claim 3, characterized in that: A coil top counterbore (1-1) is provided at the top of the coil (1), and a coil bottom counterbore (1-2) is provided at the bottom. A coil top sealing ring (6) is provided in the coil top counterbore (1-1).

8. A normally open piston cooling control solenoid valve according to claim 3, characterized in that: A groove (7-1) axially penetrating the push rod (7) is provided on the push rod (7), and an axial through hole is provided on the bracket (10). Among them, the axial through hole of the bracket is sleeved on the outer circle of the fixed iron core flange (9-1); The bottom end of the push rod (7) passes through the axial through hole of the fixed iron core (9) and presses on the top surface of the valve core (14), The spring (15) is installed on the outer circle of the head of the valve core (14).

9. A normally open piston cooling control solenoid valve according to claim 1, characterized in that: A spring seat flange (14-1) integral with the valve core (14) is provided at the top of the valve core (14).

10. A normally open piston cooling control solenoid valve according to claim 7, characterized in that: A bracket upper sealing ring (11) is provided in the recess formed by the outer circle of the fixed iron core flange (9-1) and the coil bottom counterbore (1-2); A bracket lower sealing ring (12) is provided in the recess formed by the outer circle of the fixed iron core flange (9-1) and the valve sleeve top counterbore (13-2).

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