Double-piston electromagnetic valve

Abstract

The utility model discloses a double-piston electromagnetic valve which is characterized by comprising a valve body, a large-diameter piston, a small-diameter piston, a piston connecting rod, a first table top, a pilot valve, a second table top, a first channel, a second channel, an upper valve cover, a lower valve cover, a large-diameter cavity and a small-diameter cavity. The valve body is composed of an upper portion, a middle portion and a lower portion, a large-diameter piston is arranged in an upper large-diameter cavity, a small-diameter piston is arranged in a lower small-diameter cavity, the two pistons are connected and combined into a whole through a piston connecting rod, and a leakage channel is arranged inside the two pistons. A second channel is arranged on a small-diameter cavity at the lower part of the valve body and is an outflow channel, and an inflow channel is arranged at the middle part or the lower part of the valve body; the top of the valve body is provided with an upper valve cover which is provided with a pilot electromagnetic valve; a lower valve cover is arranged at the bottom of the valve body; the valve body, the upper valve cover and the lower valve cover are combined into a closed whole; a double-piston structure is adopted, and the opening degree of the valve is greatly increased.

Description

TECHNICAL FIELD

[0001] The utility model relates to the technical field of electromagnetic valve, specifically to a double piston electromagnetic valve. BACKGROUND

[0002] At present, the existing electromagnetic valve has a diaphragm electromagnetic valve and a piston electromagnetic valve, both of which have very small opening degree, resulting in very large resistance, and because the moving distance of the diaphragm and the piston in the electromagnetic valve is limited, a large opening degree, large diameter and super large diameter electromagnetic valve cannot be made, and the use is limited. SUMMARY

[0003] The utility model discloses a double piston electromagnetic valve, which has a large valve opening degree, thereby greatly reducing the fluid resistance of the valve, making it possible to make a larger diameter electromagnetic valve, and having a reverse check function.

[0004] The utility model provides a technical scheme of a double piston electromagnetic valve, which is characterized in that it comprises a valve body, a large-diameter piston, a small-diameter piston, a piston connecting rod, a first table, a pilot electromagnetic valve, a second table, a first channel, a second channel, an upper valve cover, a lower valve cover, a large-diameter cavity and a small-diameter cavity.

[0005] The valve body has a cylindrical structure with a large inner cavity at the top and a small inner cavity at the bottom; the valve body is composed of an upper part, a middle part and a lower part, the upper part is a large-diameter cavity, the lower part is a small-diameter cavity, and the cross section of the large-diameter cavity is larger than that of the small-diameter cavity; a large-diameter piston is arranged in the large-diameter cavity, the large-diameter piston is sealed with the large-diameter cavity and moves up and down in the large-diameter cavity, a small-diameter piston is arranged in the small-diameter cavity, there is a clearance between the small-diameter piston and the small-diameter cavity, and the small-diameter piston moves up and down in the small-diameter cavity; the large-diameter piston and the small-diameter piston are connected by a piston connecting rod, the large-diameter piston, the small-diameter piston and the piston connecting rod are combined into one body to form a double piston assembly, and the double piston assembly can move up and down; a leakage channel is arranged in the double piston assembly, and the leakage channel communicates with the large-diameter cavity and the small-diameter cavity.

[0006] At least one first channel is arranged on the middle part of the valve body or the lower valve cover, and the first channel is an inflow channel; a second channel is arranged on the small-diameter cavity of the lower part of the valve body, and the second channel is an outflow channel.

[0007] A table is arranged on at least one of the upper and lower parts of the channel opening of the second channel in the valve body, the table on the upper part of the channel opening of the second channel is a first table, the table on the lower part of the channel opening of the second channel is a second table, and the first table and the second table respectively correspond to the upper and lower parts of the small-diameter piston and are sealed.

[0008] The valve body top is provided with an upper valve cover, the upper valve cover is provided with a pilot electromagnetic valve, the pilot electromagnetic valve is provided with a pilot valve first interface and a pilot valve second interface, the pilot valve first interface is connected with the first channel, or is directly or indirectly connected with the second channel, and the pilot valve second interface is connected with the inside of the large-diameter cavity.

[0009] The valve body bottom is provided with a lower valve cover, and the valve body 1 and the upper and lower valve covers are combined into a closed whole.

[0010] Further, Bernoulli pressure increasing mechanisms are arranged in the valve body, the inside and the second channel, the Bernoulli pressure increasing mechanism is composed of a channel part and a reduced-diameter part, the reduced-diameter part is arranged in the second channel, the inside diameter of the reduced-diameter part is partially reduced or is a throat structure, the equivalent flow area of the reduced-diameter part is smaller than that of the second channel, the channel part is arranged in the valve body or outside, one end of the channel part is inserted into the reduced-diameter part, and the other end of the channel part is connected with the lower cavity of the second channel in the valve body or is connected with the pilot valve first interface.

[0011] Further, the first channel is arranged in the middle part of the valve body and is an upper channel, a first table is arranged between the upper channel and the second channel in the valve body, and the first table is sealed with the upper part of the small-diameter piston.

[0012] Further, the first channel is arranged on the lower valve cover and is a lower channel, a second table is arranged in the lower part of the second channel in the valve body, and the second table is sealed with the lower part of the small-diameter piston.

[0013] Further, the first channel is arranged in the middle part of the valve body and on the lower valve cover and is an upper channel and a lower channel respectively, the upper channel is a flow inlet, the lower channel is a second flow outlet, and the first table and the second table are respectively sealed with the upper part and the lower part of the small-diameter piston.

[0014] Further, a power-assisted closing mechanism is arranged in the valve body, the upper and lower valve covers and the double-piston assembly, the power-assisted closing mechanism is composed of an adjustable limiting part and an elastic part, the adjustable limiting part is arranged on the inner wall of the valve body and the upper and lower valve covers, and the elastic part is arranged in the inner hole of the double-piston assembly.

[0015] Further, a hole is arranged in the double-piston assembly, a homing spring is arranged in the hole, the homing spring is a tension spring or a compression spring, one end of the homing spring is connected with the double-piston assembly, the other end of the homing spring acts on the lower part of the upper valve cover or the upper part of the lower valve cover, and the spring force of the homing spring provides power for the up-down movement of the double-piston assembly.

[0016] Further, a damping mechanism is arranged at the transition position between the upper valve body and the middle valve body of the valve body or the upper part of the lower valve cover, and the damping mechanism plays a damping role in the movement of the double-piston assembly.

[0017] Further, a one-way valve is arranged in the lower part of the second interface of the pilot valve or in the leakage passage.

[0018] Further, at least one more passage is arranged in the same radial position of the second passage of the lower part of the valve body.

[0019] Further, the valve body is of any shape; a sensor for detecting the position of the double-piston assembly is arranged on the upper or lower valve cover or on the valve body.

[0020] The utility model discloses the beneficial effects of:

[0021] 1. By Bernoulli effect, control pressure difference increases, control effect and reliability improve obviously;

[0022] 2. Double-piston structure is adopted, and the opening of the valve is greatly increased, and the electromagnetic valve can be made into large-diameter and super-large-diameter;

[0023] 3. Damping mechanism is adopted, and the impact of opening and closing of the valve is small;

[0024] 4. Power-assisted closing mechanism is adopted, and the reliability of closing is greatly improved;

[0025] 5. Homing spring is adopted, and the valve has a fixed initial state. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 It is the structure schematic drawing of the utility model;

[0027] Figure 2 It is the structure schematic drawing of the utility model with Bernoulli pressure-increasing mechanism and power-assisted closing mechanism;

[0028] Figure 3 It is the structure schematic drawing of the utility model with throat pipe type Bernoulli pressure-increasing mechanism, power-assisted closing mechanism and homing spring;

[0029] Figure 4 It is a short valve body structure schematic drawing of the utility model;

[0030] Figure 5 It is the structure schematic drawing of the utility model with the lower passage being an inflow passage;

[0031] Figure 6 It is the structure schematic drawing of the utility model with the lower passage of the short valve body being an inflow passage when closing;

[0032] Figure 7 It is the structure schematic drawing of the utility model with the lower passage of the short valve body being an inflow passage when opening;

[0033] Figure 8 It is the structure schematic drawing of the utility model with multiple second passages and one-way valve;

[0034] Figure 9 is the structural diagram of the utility model with upper passage and lower passage;

[0035] Figure 10 is the structural diagram of the utility model with multiple second passages and upper and lower passages.

[0036] In the figure: 1 valve body, 2 large diameter piston, 3 small diameter piston, 4 piston connecting rod, 5 first table, 6 pilot solenoid valve, 7 second table, 8 Bernoulli pressure increasing mechanism, 9 first passage, 10 second passage, 11 upper valve cover, 12 lower valve cover, 13 power closing mechanism, 14 spring seat, 15 damping mechanism, 16 homing spring, 18 large diameter cavity, 19 small diameter cavity, 20 double piston assembly, 21 leakage passage, 22 pilot valve first interface, 23 pilot valve second interface, 24 adjustable limit part, 25 elastic part, 26 passage part, 27 reduced diameter part, 31 sensor, 32 check valve, 91 upper passage, 92 lower passage. DETAILED DESCRIPTION

[0037] In order to better understand and implement, the utility model is described in detail below in conjunction with the drawings.

[0038] As Figure 1 , 2 , 3, a double-piston solenoid valve, which is composed of a valve body 1, a large diameter piston 2, a small diameter piston 3, a piston connecting rod 4, a first table 5, a pilot solenoid valve 6, a second table 7, a Bernoulli pressure increasing mechanism 8, a first passage 9, a second passage 10, an upper valve cover 11, a lower valve cover 12, a large diameter cavity 18, and a small diameter cavity 19.

[0039] The valve body 1 is a cylindrical structure with a large upper cavity and a small lower cavity, and is composed of an upper part, a middle part, and a lower part. The upper part is the large diameter cavity 18, and the lower part is the small diameter cavity 19. The cross-sectional area of the large diameter cavity 18 is larger than that of the small diameter cavity 19. The large diameter piston 2 is installed in the large diameter cavity 18 and can move up and down in a sealed manner. The small diameter piston 3 is installed in the small diameter cavity 19 and can move up and down with a clearance. The large diameter piston 2 and the small diameter piston 3 are connected by the piston connecting rod 4. The large and small diameter pistons and the piston connecting rod 4 are combined into one body to form a double-piston assembly 20. The diameter of the connecting rod 4 is less than or equal to the diameter of the small diameter piston 3, and the double-piston assembly 20 can move up and down in the valve body 1. A leakage passage 21 is provided in the double-piston assembly 20, which connects the upper part of the large diameter piston 2 and the lower part of the small diameter piston 3.

[0040] The first channel 9 is formed in the middle of the valve body 1, and the first channel 9 is an upper channel 91, the upper channel 91 is a fluid inflow channel, and the upper channel 91 is communicated with the inside of the valve body 1; the second channel 10 is formed in the position of the small-diameter cavity 19 of the lower part of the valve body 1, the second channel 10 is an outflow channel, and the upper channel 91 and the second channel 10 can be circular, square or any other shape; the two ends of the upper channel 91 and the second channel 10 can be connected in any form such as flange connection, welding or elbow connection.

[0041] At least one of the channel ports of the second channel 10 in the valve body 1 is provided with a platform, the platform on the channel port of the second channel 10 is a first platform 5, the platform under the channel port of the second channel 10 is a second platform 7, and at least one platform corresponds to the sealing of the small-diameter piston 3, and simultaneously defines the limit position of the movement of the double-piston assembly 20;

[0042] The Bernoulli pressure increasing mechanism 8 is installed in the valve body 1 and the second channel 10, the Bernoulli pressure increasing mechanism 8 is composed of a channel part 26 and a reduced-diameter part 27; the reduced-diameter part 27 is arranged in the second channel 10, the equivalent flow area of the reduced-diameter part 27 is reduced, so that the fluid flow rate is increased, and low pressure is generated; the channel part 26 is arranged in the valve body 1 or outside, one end of the channel part 26 is connected to the lower part of the inner cavity of the valve body 1, and the opening is arranged in the lower part of the second channel 10, the other end of the channel part 26 is inserted into the reduced-diameter part 27, and the reduced-diameter part 27 is locally reduced in inner diameter or adopts a reduced-diameter throat structure; the fluid flow rate in the reduced-diameter part 27 is increased compared with the fluid flow rate in the upper channel 91; according to the Bernoulli equation, the effect of reducing pressure is generated;

[0043] The upper valve cover 11 is installed at the top end of the valve body 1, and the pilot electromagnetic valve 6 is installed on the upper valve cover 11; the pilot electromagnetic valve 6 has a larger diameter than the diameter of the leakage channel 21, and has a larger flow capacity than the flow capacity of the leakage channel 21; the pilot electromagnetic valve 6 has a pilot valve first interface 22 and a pilot valve second interface 23, the pilot valve first interface 22 is connected to the upper channel 91 through an internal channel or an external channel, and the pilot valve second interface 23 is connected to the large-diameter cavity 18; a one-way valve 32 can be installed at the lower part of the pilot valve second interface 23 to prevent backflow of fluid;

[0044] The lower valve cover 12 is installed at the bottom of the valve body 1, and the sensor 31 is installed on the lower valve cover 12; the sensor 31 is a magnetic sensor, and has a shielding structure with the inner cavity of the valve body 1; the sensor 31 can also be arranged inside the valve body 1 and led out through a lead terminal or in other forms;

[0045] The valve body 1, the upper valve cover and the lower valve cover are combined into a closed whole.

[0046] Further, the valve body 1 and the double piston assembly 20 are provided with a force-aided closing mechanism 13, which is composed of an adjustable limiting part 24 and an elastic part 25. The elastic part 25 is installed in the inner hole of the double piston assembly 20, and includes a spring and a spring seat 14. The spring seat 14 is constrained in the hole and can move up and down under force. The adjustable limiting part 24 is installed on the lower valve cover 12. When the double piston assembly 20 moves downward, the spring seat 14 interacts with the adjustable limiting part 24, and the spring is compressed, thereby generating a force to push the double piston assembly 20 to move upward. By adjusting the adjustable limiting part 24, the initial interaction point of the double piston assembly 20 and the elastic part 25 can be changed, thereby providing different elastic forces.

[0047] The force-aided closing mechanism 13 can also be installed on the upper end or the lower end of the valve body 1. The force-aided closing mechanism 13 can increase the closing force of the valve.

[0048] Further, a hole is formed in the center of the double piston assembly 20, and a homing spring 16 is installed in the hole. The homing spring 16 is a tension spring or a compression spring. One end of the homing spring 16 is connected to the double piston assembly 20, and the other end is connected to the lower part of the upper valve cover 11 or the upper part of the lower valve cover 12. The elastic force of the homing spring 16 enables the double piston assembly 20 to move up and down.

[0049] The working principle of the above embodiment is as follows:

[0050] Fluid flows from the upper channel 91, and fluid pressure directly acts on the lower part of the large-diameter piston 2 and the upper part of the small-diameter piston 3. At this time, the pilot electromagnetic valve 6 is closed. The fluid pressure in the upper part of the large-diameter cavity 18 is discharged through the leakage channel 21. Finally, the pressure in the small-diameter cavity 19 is balanced, and the pressure in the second channel 10 is equal. Since the pressure in the upper channel 91 is greater than the pressure in the second channel 10, the large-diameter piston 2 is subjected to an upward force, and the small-diameter piston 3 is subjected to a downward force. Since the cross-sectional area of the large-diameter piston 2 is greater than that of the small-diameter piston 3, the force direction of the entire double piston assembly 20 is upward, pulling the small-diameter piston 3 to move upward, and the upper part of the small-diameter piston 3 is sealed with the first land 5.

[0051] When the pilot electromagnetic valve 6 is opened, the fluid pressure in the upper channel 91 flows into the large-diameter cavity 18 through the pilot valve first interface 22 and the pilot valve second interface 23. The passage diameter of the pilot electromagnetic valve 6 is greater than that of the leakage channel 21, that is, the flow capacity is greater than that of the leakage channel 21. Therefore, the pressure on the upper surface of the large-diameter piston 2 is close to the pressure in the upper channel 91, that is, the pressure on the upper and lower surfaces of the large-diameter piston 2 is almost equal. At this time, the small-diameter piston 3 is still subjected to the downward force generated by the pressure difference between the upper channel 91 and the second channel 10, and the double piston assembly 20 moves downward, thereby opening the valve. Fluid flows through the first land 5 to the second channel 10, and the valve is opened.

[0052] When the pilot solenoid valve 6 is closed again, the pressure inside the large diameter cavity 18 leaks into the second channel 10 through the leakage channel 21, so that the pressure on the upper part of the large diameter piston 2 is almost the same as the pressure in the second channel 10, and due to the Bernoulli pressure-increasing mechanism 8, the pressure on the upper surface of the large diameter piston 2 is further reduced. The pressure on the lower part of the large diameter piston 2 is large, and the pressure on the upper part is small. The large diameter piston 2 is subjected to an upward force. At this time, the pressure difference between the upper and lower parts of the small diameter piston 3 is almost the same, and there is almost no force. Even if there is a pressure difference between the upper and lower parts of the small diameter piston 3, it will not exceed the pressure difference between the upper and lower parts of the large diameter piston 2. Moreover, since the cross-sectional area of the large diameter piston 2 is larger than that of the small diameter piston 3, the double-piston assembly 20 is subjected to an upward force and moves upward. The upper part of the small diameter piston is tightly sealed with the first table 5.

[0053] During the upward movement of the double-piston assembly 20, the pressure difference experienced by the large and small double-piston assemblies will increase at the same time. However, no matter how high the pressure difference rises, the cross-sectional area of the large diameter piston 2 is larger than that of the small diameter piston 3, so the force is still upward. The double-piston assembly 20 will not lose the power to move upward due to the increase in the pressure difference. On the contrary, the upward force will increase due to the increase in the pressure difference between the upper channel 91 and the second channel. This positive feedback and positive incentive effect can make the valve eventually close.

[0054] The homing spring 16 is used during the upward movement, and at the same time, the homing spring 16 also exerts an upward pulling force, promoting the closing of the valve.

[0055] When the double-piston assembly 20 moves downward with a certain speed and impact force, the elastic part 25 of the power-assisted closing mechanism 13 is compressed to absorb the impact force of the double-piston assembly 20, thereby playing a buffering role. At the same time, it also plays a role in compressing and storing energy. After the elastic part 25 of the power-assisted closing mechanism 13 is compressed, an upward force is generated, which counteracts the frictional force between the double-piston assembly 20 and the inner wall of the cavity. In this way, the valve can be opened with smaller force.

[0056] Working principle of Bernoulli pressure-increasing mechanism 8: The channel part 26 of the Bernoulli pressure-increasing mechanism 8 is connected to the reduced diameter part 27. Due to the reduced diameter of the reduced diameter part 27, the flow rate increases. According to the Bernoulli equation of fluid mechanics, the faster the flow rate, the lower the pressure. Therefore, at the outlet position of the channel part 26 of the Bernoulli pressure-increasing mechanism 8, the pressure is very low due to the Bernoulli effect. This low pressure passes through the channel part 26 to the lower part of the small diameter piston 3, and then through the leakage channel 21 to the upper part of the large diameter piston 2 in the large diameter cavity 18. This makes the pressure difference between the upper and lower parts of the large diameter piston 2 increase, so that the double-piston assembly 20 can generate a larger upward closing force. This plays an important role for double-piston solenoid valves that rely on their own pressure difference to close.

[0057] Although the Bernoulli pressure mechanism 8 has a reduced diameter structure, the pressure after the diameter expansion of the Bernoulli reduced diameter part 27 is greater than the pressure in the reduced diameter part 27; that is, a smaller throttling pressure loss can obtain a greater control pressure difference.

[0058] As shown in Figure 4 , it is a short valve body double piston electromagnetic valve, in order to reduce the use of materials, or in order to make the fluid resistance lower, adopt streamlined flow channel, or in order to avoid the influence of vortex, even in order to prevent fluid noise, the shape of valve body 1 can be any shape;

[0059] Damping mechanism 15 is installed on the upper part of lower valve cover 12, which can play the role of power closing mechanism 13 and limit the position of double piston assembly 20.

[0060] As shown in Figure 5 , the first channel 9 is provided on the lower valve cover 12, which is the lower channel 92, and the lower channel 92 is the inflow channel; the second channel 10 is the outflow channel, and the Bernoulli pressure mechanism 8 is installed in the second channel 10; the channel part 26 is connected with the guide valve first interface 22 at one end and the reduced diameter part 27 at the other end; the guide valve first interface 22 and the guide valve second interface 23 are connected interchangeably; the second platform 7 is sealed with the lower part of the small diameter piston 3, and the first platform 5 plays the role of limiting position, which can also be cancelled; the homing spring 16 is installed in the double piston assembly 20.

[0061] The working principle of the above embodiment is as follows:

[0062] When the double piston electromagnetic valve is opened to closed, the initial state is that the double piston assembly 20 is on the upper part of the valve body 1, and then the fluid flows into the lower channel 92, and the pressure flows into the upper part of the large diameter piston 2 through the leakage channel 21; at this time, the electromagnetic guide valve 6 is closed, the pressure in the upper part of the large diameter piston 2 is the inflow pressure of the lower channel 92, and the lower part of the large diameter piston 2 is in communication with the second channel 10, which is the outflow pressure; since the inflow pressure is greater than the outflow pressure, the large diameter piston 2 is subjected to the pressure difference between the upper part and the lower part, and at this time, the lower part of the small diameter piston 3 is sealed with the second platform 7 under the action of the homing spring 16.

[0063] When the electromagnetic guide valve 6 is opened, the pressure in the upper part of the large diameter piston 2 flows to the second channel 10 through the channel part 26 and the guide valve first interface 22; since the flow capacity of the guide valve 6 is greater than that of the leakage channel 21, the pressure in the upper and lower parts of the large diameter piston 2 is almost equal to the pressure in the second channel 10, and the large diameter piston is almost not subjected to force, while the small diameter piston 3 is still subjected to upward force, so the double piston assembly 20 moves upward, and the valve is opened.

[0064] The Bernoulli increasing mechanism 8 serves to increase the control pressure difference.

[0065] In order to increase the pressure on the upper part of the large-diameter piston 2 , the lower part of the leakage channel 21 can also be connected to an extension pipeline, extending to the interior of the lower channel 92 .

[0066] like Figure 6 As shown, a short valve body double-piston solenoid valve with the lower channel 92 being the inflow channel, and the valve is in a closed state at this time.

[0067] like Figure 7 As shown, it is a short valve body double-piston solenoid valve with the lower channel 92 as the inflow channel. The diameter of the piston connecting rod 4 is increased to the same as the diameter of the small-diameter piston 3 and is combined into one body with the small piston 3; if necessary, a seal is installed at the lower end of the small piston 3, and the valve is in an open state at this time.

[0068] like Figure 8 As shown, the first channel 9 is provided in the middle of the valve 1 and is the upper channel 91. At the lower part of the valve body 1, at the same radial position as the second channel 10, at least one more channel is provided, which has the same function as the second channel 10.

[0069] A one-way valve 32 is installed at the bottom of the leakage channel 21 to prevent the fluid from flowing into the large-diameter cavity 18 when the fluid flows in the reverse direction, thereby preventing the double-piston solenoid valve from flowing back.

[0070] A damping mechanism 15 is installed at the transition position between the upper and middle parts of the valve body 1. The damping mechanism 15 has a damping effect on the movement of the dual-piston assembly 20 to reduce the impact, and only plays a damping role during the movement; the damping mechanism 15 can be any form of compressed gas damping, friction damping, slow discharge damping, etc., and the damping process can be full damping or partial damping;

[0071] The damping mechanism 15 and the power-assisted closing mechanism 13 can be integrated into one piece; the damping mechanism 15 can also be integrated into the second table surface 7 .

[0072] like Figure 9 As shown, there are two first channels 9, an upper channel 91 is provided in the middle of the valve body 1, and a lower channel 92 is provided on the lower valve cover 12. The upper channel 91 is an inflow channel, and the lower channel 92 is a second outflow channel. The first table 5 is at the upper part of the second channel 10, and the second table 7 is at the lower part of the second channel 10 in the valve body. The first table is sealed with the upper part of the small-diameter piston 3, and the second table 7 is sealed with the lower part of the small-diameter piston 3.

[0073] like Figure 10 As shown, there are two first channels 9 , an upper channel 91 is provided in the middle of the valve body 1 , a lower channel 92 is provided on the lower valve cover 12 , and multiple channels are opened in the radial position of the second channel 10 .

[0074] In addition, all channels are not limited to circular shape, can be any shape; all connecting pipes can adopt corrugated pipe, in order to reduce the flow resistance, all channels can adopt the most suitable any shape flow channel, in order to ensure the sealing, increase the sealing element in the place needing sealing also within the protection scope of the utility model, or the appearance is any shape, but the internal structure or control principle is same with the utility model. And, the edge position chamfer or R transition also within the protection scope of the utility model. The technical features of the above described embodiments can be combined arbitrarily, in order to make the description simple, not all possible combinations of each technical feature in the above described embodiments are described, however, as long as the combination of these technical features does not exist contradiction, should be considered as the range of the present application.

[0075] The above described embodiments only express several embodiments of the utility model, the description is more specific and detailed, but it cannot be understood as the limitation of the utility model patent range. It should be pointed out that for ordinary skilled person in the art, without departing from the concept of the utility model, can make several deformation and improvement, these all belong to the protection scope of the utility model. Therefore, the protection scope of the utility model patent should be according to the attached claims.

[0076] It should be understood that the technical features not described in detail in the specification all belong to the prior art. Although the embodiments of the present application are described, the present application is not limited to the above specific embodiments, the above specific embodiments are only illustrative, not restrictive, and ordinary skilled person in the art can make more forms under the inspiration of the present application without departing from the scope of the patent claims, and these all belong to the protection scope of the present application.

Claims

1. A dual piston solenoid valve characterized by, It includes valve body (1), large diameter piston (2), small diameter piston (3), piston connecting rod (4), first table (5), pilot solenoid valve (6), second table (7), first channel (9), second channel (10), upper valve cover (11), lower valve cover (12), large diameter cavity (18), small diameter cavity (19); The valve body (1) is a cylinder structure with large upper cavity and small lower cavity; The valve body (1) is composed of upper part, middle part and lower part, the upper part is large diameter cavity (18), the lower part is small diameter cavity (19), the cross section of large diameter cavity (18) is larger than that of small diameter cavity (19); The large diameter piston (2) is arranged in the large diameter cavity (18), the large diameter piston (2) is sealed with the large diameter cavity (18) and moves up and down in the large diameter cavity (18), the small diameter piston (3) is arranged in the small diameter cavity (19), there is a movable gap between the small diameter piston (3) and the small diameter cavity (19) and the small diameter piston (3) moves up and down in the small diameter cavity (19); The large diameter piston (2) and the small diameter piston (3) are connected by the piston connecting rod (4), the large and small diameter pistons and the piston connecting rod (4) are combined into an integrated body, forming a double piston assembly (20) which can move up and down; The double piston assembly (20) is internally provided with a leakage channel (21), the leakage channel (21) communicates with the large diameter cavity (18) and the small diameter cavity (19); The middle part of the valve body (1) or the lower valve cover (12) is provided with at least one first channel (9), and the first channel (9) is an inflow channel; The lower part of the valve body (1) is provided with a second channel (10) on the small diameter cavity (19), and the second channel (10) is an outflow channel; The second channel (10) in the valve body (1) is provided with a table at least at one of the upper and lower channel openings, the table at the upper channel opening of the second channel (10) is a first table (5), and the table at the lower channel opening of the second channel (10) is a second table (7), which correspond to the upper and lower small diameter pistons (3) respectively; The top of the valve body (1) is provided with an upper valve cover (11), the upper valve cover (11) is provided with a pilot solenoid valve (6), the pilot solenoid valve (6) has a pilot valve first interface (22) and a pilot valve second interface (23), the pilot valve first interface (22) is connected with the first channel (9), or directly or indirectly connected with the second channel (10), and the pilot valve second interface (23) is connected with the inside of the large diameter cavity (18); The diameter of the pilot solenoid valve (6) is larger than the equivalent diameter of the leakage channel (21); The bottom of the valve body (1) is provided with a lower valve cover (12), and the valve body (1) is combined with the upper and lower valve covers into a closed integrated body.

2. A dual piston solenoid valve according to claim 1, characterized in that Bernoulli pressure increasing mechanism (8) is arranged in the valve body (1) and the second channel (10), the Bernoulli pressure increasing mechanism (8) is composed of channel part (26) and reduced diameter part (27), the reduced diameter part (27) is arranged in the second channel (10), the reduced diameter part (27) is partially reduced in the inside diameter, and the equivalent flow area is smaller than the second channel (10), the channel part (26) is arranged in the valve body (1) or outside, one end of the channel part (26) is inserted into the reduced diameter part (27), and the other end of the channel part (26) is connected to the lower cavity of the second channel (10) in the valve body (1) or connected to the first interface (22) of the pilot valve.

3. A dual piston solenoid valve according to claim 1, wherein The first channel (9) is arranged in the middle of the valve body (1) and is an upper channel (91), and the first platform (5) is arranged between the upper channel (91) and the second channel (10) in the valve body (1) and is sealed with the upper part of the small-diameter piston (3).

4. A dual piston solenoid valve according to claim 1, wherein The first channel (9) is arranged on the lower valve cover (12) and is a lower channel (92), and the second platform (7) is arranged in the lower part of the second channel (10) in the valve body (1) and is sealed with the lower part of the small-diameter piston (3).

5. A dual piston solenoid valve according to claim 1, wherein The first channel (9) is arranged in the middle of the valve body (1) and on the lower valve cover (12) and is an upper channel (91) and a lower channel (92) respectively, the upper channel (91) is an inlet, and the lower channel (92) is a second outlet, and the first platform (5) and the second platform (7) are respectively sealed with the upper and lower parts of the small-diameter piston (3).

6. A dual piston solenoid valve according to claim 1, wherein The power-assisted closing mechanism (13) is arranged in the valve body (1), the upper and lower valve covers and the double-piston assembly (20), the power-assisted closing mechanism (13) is composed of an adjustable limiting part (24) and an elastic part (25), the adjustable limiting part (24) is arranged on the inner wall of the valve body (1) and the upper and lower valve covers, and the elastic part (25) is arranged in the inner hole of the double-piston assembly (20).

7. A dual piston solenoid valve according to claim 1, wherein The hole is arranged in the double-piston assembly (20), the homing spring (16) is arranged in the hole, one end of the homing spring (16) is connected with the double-piston assembly (20), and the other end of the homing spring (16) acts on the lower part of the upper valve cover (11) or the upper part of the lower valve cover (12).

8. A dual piston solenoid valve according to claim 1, wherein The damping mechanism (15) is arranged at the transition position between the upper valve body and the middle valve body of the valve body (1) or the upper part of the lower valve cover (12).

9. A dual piston solenoid valve according to claim 1, wherein The one-way valve (32) is arranged in the lower part of the second interface (23) of the pilot valve or the leakage channel (21).

10. A dual piston solenoid valve according to claim 1, wherein The valve body (1) is of any shape, at least one channel is additionally arranged at the same radial position of the second channel (10) of the lower part of the valve body (1), and the sensor (31) for detecting the position of the double-piston assembly is arranged on the upper and lower valve covers or the valve body (1).

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