Normally closed two-position three-way PWM solenoid valve with non-magnetic gasket ball valve structure

Abstract

The application belongs to a two-position three-way PWM electromagnetic valve, and aims at solving the problems of complex structure, slow response speed, high quality requirement of parts processing, high requirement of product assembly process and large leakage of existing two-position three-way high-speed on-off electromagnetic valve, and provides a normally closed two-position three-way PWM electromagnetic valve with a non-magnetic gasket ball valve structure, wherein the inner surface of the top of the stop iron is provided with a boss, the bottom of the boss is provided with a counterbore, the surface of the armature is coated with a non-magnetic coating, the top is provided with a first mounting hole, the elastic component is located in the counterbore and the first mounting hole, the coil is wound on the upper part of the armature and the outer wall of the boss, one end of the top rod is fixed with the armature, and the other end is arranged opposite to the steel ball, the first through hole is arranged in the valve body along the axial direction, is sleeved on the outer side of the lower part of the armature, the inner wall of the first through hole is provided with a limiting boss, the valve seat is fixed on the bottom of the first through hole, a cavity is formed between the top of the valve seat and the limiting boss, and the steel ball is located in the cavity.

Description

Technical Field

[0001] This invention pertains to two-position three-way PWM solenoid valves, specifically relating to a normally closed two-position three-way PWM solenoid valve with a ball valve structure without magnetic isolation gaskets. Background Technology

[0002] In various hydraulic systems, PWM solenoid valves (pulse width modulation solenoid valves, also known as high-speed switching solenoid valves) can be used to achieve the switching function of general solenoid valves, and can also use PWM signals to regulate the pressure and flow at the outlet of the solenoid valve. Although its regulation accuracy is lower than that of proportional solenoid valves, it has the advantages of outstanding anti-pollution ability, high reliability and small size.

[0003] Chinese patent CN203488462U discloses a two-position three-way high-speed switching solenoid valve structure, which uses a steel ball, valve seat, and stop to form the main valve, realizing the two-position three-way function. However, it has a slow response speed, complex structure, and problems with large leakage between the inlet and outlet, as well as between the outlet and the return port.

[0004] Chinese patent CN201963996U discloses a two-position three-way high-speed switching solenoid valve with a plate-type main valve structure. It uses a thin-plate valve seat, a hollow cylindrical valve core and a valve body to form the main valve, realizing two-position three-way function. Its structure is complex, the processing quality of the parts is high, especially the product assembly process is high, and there are also problems of large leakage between the inlet and outlet, and between the outlet and the return port. Summary of the Invention

[0005] To address the technical problems of existing two-position three-way high-speed switching solenoid valves, such as complex structure, slow response speed, high requirements for component processing quality, high requirements for product assembly process, and large leakage between inlet and outlet, as well as between outlet and return port, this invention provides a normally closed two-position three-way PWM solenoid valve with a non-magnetic gasket ball valve structure.

[0006] To achieve the above objectives, the present invention employs the following technical solution:

[0007] A normally closed two-position three-way PWM solenoid valve with a non-magnetic gasket ball valve structure includes a stop, armature, coil, valve body, push rod, valve seat, steel ball, connector, and elastic component; its special feature is that...

[0008] The stop is a hollow cylinder with an open bottom. The inner surface of the top of the stop has a cylindrical boss, and the bottom of the boss has a countersunk hole.

[0009] The armature surface is coated with a non-magnetic coating and is coaxially arranged with the boss. A first mounting hole is opened at the top of the armature and a second mounting hole is opened at the bottom. The first mounting hole and the second mounting hole are connected through a connecting hole. The diameter of the connecting hole is smaller than that of the first mounting hole. The first mounting hole, the second mounting hole, the connecting hole and the countersunk hole are coaxially arranged.

[0010] One end of the elastic member abuts or connects with the bottom of the countersunk hole, and the other end abuts or connects with the bottom of the first mounting hole;

[0011] The coil is wound around the upper part of the armature and the outer wall of the boss, and is located between the outer wall of the boss and the inner wall of the stop.

[0012] One end of the top rod is fixedly installed in the second mounting hole, and the other end is positioned opposite to the steel ball;

[0013] The valve body has a first through hole axially inside, which is sleeved on the lower outer side of the armature. The inner wall of the first through hole is provided with a limiting boss. The valve body has a return oil port that communicates with the first through hole radially below the armature.

[0014] The valve seat is fixed to the bottom of the first through hole, and a cavity is formed between the top of the valve seat and the limiting boss. The steel ball is located in the cavity, and the height of the cavity allows the steel ball to move axially within the cavity. The valve seat is provided with a channel for connecting the bottom end of the first through hole and the cavity. The valve body is provided with an oil outlet that communicates with the cavity in a radial direction at the cavity location.

[0015] The coil is connected to an external power supply via a connector, and the connector input is controlled by a PWM signal.

[0016] Furthermore, a limiting step is provided at the end of the push rod near the steel ball. The limiting step abuts against the upper surface of the limiting protrusion to limit the displacement of the push rod towards the steel ball.

[0017] Furthermore, it also includes mounting plates;

[0018] The mounting plate is fixedly connected radially along the bottom of the stop;

[0019] The outer wall of the valve body is fixedly connected to the inner wall of the mounting plate;

[0020] The lower end of the coil is attached to the mounting plate.

[0021] Furthermore, a first mounting groove is provided circumferentially on the outer wall of the valve body between the oil return port and the oil outlet for installing a first sealing ring; a second mounting groove is provided circumferentially on the outer wall of the valve body below the oil outlet for installing a second sealing ring.

[0022] Furthermore, a first filter screen is provided at the bottom of the first through hole below the valve seat, and the outer edge of the first filter screen is sealed to the inner wall of the first through hole;

[0023] A second filter screen is provided at the oil outlet.

[0024] Furthermore, a bearing is installed on the outside of the push rod below the armature, and the bearing is installed through a bearing seat fixed in the first through hole.

[0025] Furthermore, the outer wall of the valve seat is fitted and connected to the inner wall of the first through hole, and a second through hole is provided in the valve seat along the axial direction to connect the bottom end of the first through hole with the cavity.

[0026] Furthermore, the connector is installed on the outer wall of the stop, the metal plate inside the output end of the connector is connected to the enameled wire inside the coil, and the input end is connected to an external power supply.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] 1. The present invention relates to a normally closed two-position three-way PWM solenoid valve with a non-magnetic gasket ball valve structure. It adopts an electromagnet structure without a magnetic gasket. The steel ball is pushed by the push rod to close the channel from the oil inlet to the oil outlet, and at the same time, to open the channel from the oil outlet to the oil return port. The pressure at the oil inlet pushes the steel ball to open the channel from the oil inlet to the oil outlet, and at the same time closes the channel from the oil outlet to the oil return port. With the help of PWM control, the electromagnetic attraction is large and the solenoid valve has a fast response speed.

[0029] 2. This invention employs a main valve structure composed of a steel ball and valve seat, and a steel ball and valve body. The valve body and valve seat can be machined using special processes, resulting in superior sealing performance of the solenoid valve. The integrated structure connecting the armature to the push rod, the valve body to the mounting plate, and the valve body to the stop iron eliminates the need for any adjustments during assembly, making it simple, controllable, and suitable for mass production. Furthermore, the overall structure is simple, the processing difficulty is low, and the solenoid valve has higher reliability.

[0030] 3. In this invention, the valve body is provided with a first mounting groove and a second mounting groove, and a first sealing ring and a second sealing ring are respectively installed. When the solenoid valve is actually installed and used, it can effectively prevent oil leakage from the outer wall of the valve body.

[0031] 4. In this invention, a filter screen is provided at the oil inlet to filter the incoming oil, and a filter screen is also provided at the oil outlet to minimize the damage of impurities to the solenoid valve and the impurities carried out with the flowing oil. This can effectively improve the service life of the solenoid valve and improve the quality of the flowing oil.

[0032] 6. This invention uses PWM signals for control, which can adjust the oil outlet pressure and flow rate, making the solenoid valve more flexible and intelligent to use. Attached Figure Description

[0033] Figure 1This is a schematic diagram of an embodiment of the normally closed two-position three-way PWM solenoid valve with a non-magnetic pad ball valve structure according to the present invention.

[0034] Figure 2 This is a schematic diagram of the oil flow direction of the normally closed two-position three-way PWM solenoid valve with a non-magnetic gasket ball valve structure according to the present invention (wherein, the solid arrow indicates the oil flow direction from the oil inlet to the oil outlet, and the dashed arrow indicates the oil flow direction from the oil outlet to the oil return port).

[0035] Among them, 1-stop, 2-armature, 3-coil, 4-valve body, 5-top rod, 6-valve seat, 7-steel ball, 8-connector, 9-bore, 10-counterhead, 11-first mounting hole, 12-second mounting hole, 13-connecting hole, 14-elastic component, 15-limiting boss, 16-first through hole, 17-second through hole, 18-mounting plate, 19-cavity, 20-oil return port, 21-oil outlet, 22-first mounting groove, 23-first sealing ring, 24-second mounting groove, 25-second sealing ring, 26-first filter screen, 27-second filter screen, 28-bearing, 29-bearing seat, 30-oil inlet, 31-limiting step. Detailed Implementation

[0036] The present invention will now be described in further detail with reference to the accompanying drawings:

[0037] like Figure 1 The present invention provides a normally closed two-position three-way PWM solenoid valve with a non-magnetic gasket ball valve structure, including a stop 1, an armature 2, a coil 3, a valve body 4, a push rod 5, a valve seat 6, a steel ball 7, a connector 8, and an elastic component 14.

[0038] The stop 1 is made of soft magnetic material and is a hollow cylinder with an open bottom. A cylindrical boss 9 is located on the inner surface of the top. A countersunk hole 10 for accommodating the elastic component 14 is formed at the bottom of the boss 9. The lower end of the stop 1 is fitted onto the outside of the mounting plate 18 and riveted to it. The boss 9 inside the stop 1 is coaxially arranged with the armature 2, which is located below the boss 9. There is no magnetic shielding gasket between the armature 2 and the boss 9. The surface of the armature 2 is coated with a non-magnetic coating, which acts as a magnetic shielding gasket. During operation, the residual magnetism of the stop 1 and the armature 2 is small, ensuring a release speed of less than 5ms for the solenoid valve.

[0039] The armature 2 is made of soft magnetic material and is a hollow cylinder with three through holes running along its axis. Specifically, a first mounting hole 11 is provided at the top, and a second mounting hole 12 is provided at the bottom. The first mounting hole 11 and the second mounting hole 12 are connected by a connecting hole 13. The diameter of the connecting hole 13 is smaller than that of the first mounting hole 11, so that the elastic component 14 can be confined within the first mounting hole during installation. The first mounting hole 11, the second mounting hole 12, the connecting hole 13, and the countersunk hole 10 are coaxially arranged. One end of the push rod 5 is fixedly installed in the second mounting hole 12 and is riveted to the armature 2 as a whole. The other end of the push rod 5 is positioned opposite the steel ball 7 and directly above the steel ball 7.

[0040] The elastic component 14 can be a cylindrical compression spring made of metal material, with one end abutting or connecting to the bottom of the countersunk hole 10 and the other end connecting or abutting to the bottom of the first mounting hole 11.

[0041] The coil 3 is cylindrical after being coiled, and is made of plastic and enameled wire. It is coiled and sleeved on the outer wall of the boss 9 and the upper part of the armature 2. The lower end of the coil 3 is attached to the mounting plate 18. The coil 3 is located between the outer wall of the boss 9 and the inner wall of the stop 1.

[0042] Mounting plate 18 is a thin sheet made of soft magnetic metal material and is fixedly connected to the bottom of stop 1 in the radial direction. The inner wall of mounting plate 18 is riveted to the outer wall of valve body 4 to form a whole.

[0043] The valve body 4 is made of metal and has a first through hole 16 axially formed inside. It is fitted onto the lower outer side of the armature 2. The opening at the bottom of the first through hole 16 is the oil inlet 30. A limiting boss 15 is provided on the inner wall of the first through hole 16. A bearing 28 is installed on the outside of the push rod 5 below the armature 2. The bearing 28 is installed through a bearing seat 29 fixed in the first through hole 16. The bearing seat 29 is annular and made of metal. The bearing 28 is also annular and made of wear-resistant material. It is installed inside the bearing seat 29. The push rod 5 is a multi-segment cylindrical shape made of metal and is fitted into the inner hole of the bearing 28. As a preferred embodiment, the end of the push rod 5 near the steel ball 7 is provided with a limiting step 31. The limiting step 31 abuts against the upper surface of the limiting boss 15. When the push rod 5 moves to a certain position in the direction of the steel ball 7, the limiting step 31 abuts against the limiting boss 15, and the push rod can no longer move in the direction of the steel ball 7, thus limiting the downward displacement of the push rod 5.

[0044] The valve seat 6 is made of metal and is fixed to the bottom of the first through hole 16, forming an integral part with the valve body 4. A cavity 19 is formed between the top of the valve seat 6 and the limiting boss 15. The steel ball 7 is located inside the cavity 19. The outer wall of the valve seat 6 is in close contact with the inner wall of the first through hole 16. A second through hole 17 is axially formed inside the valve seat 6 to connect the bottom end of the first through hole 16 with the cavity 19, allowing oil entering from the oil inlet 30 to enter the cavity 19 through the second through hole 17. The height of the cavity 19, the inner diameter of the second through hole 17, and the diameter of the hole at the center of the limiting boss 15 can be adjusted according to the size of the steel ball 7, so that the steel ball 7 can move axially within the cavity 19 without leaking out through the second through hole 17 or the hole at the center of the limiting boss 15. The steel ball 7 is made of metal. The valve seat 6 can be processed using special technology to form a long-life, contamination-resistant, and reliable sealing structure with the steel ball 7.

[0045] In addition, the valve body 4 has an oil outlet 21 that communicates with the cavity 19 in the radial direction at the cavity 19, and an oil return port 20 that communicates with the first through hole 16 in the radial direction below the armature 2.

[0046] In addition, to prevent impurities in the oil from damaging the inside of the solenoid valve, a first filter screen 26 is installed at the bottom of the first through hole 16 below the valve seat 6 to filter the oil entering through the oil inlet 30. The outer edge of the first filter screen 26 is sealed to the inner wall of the first through hole 16 to prevent oil from flowing through this connection. A second filter screen 27 is provided at the oil outlet 21 to filter the oil again. Both the first filter screen 26 and the second filter screen 27 can be injection molded from a metal mesh and a plastic support.

[0047] As a preferred embodiment, to prevent oil leakage from the outside of the valve body 4 after the solenoid valve is installed, a first mounting groove 22 is formed circumferentially on the outer wall of the valve body 4 between the return port 20 and the outlet port 21, and a first sealing ring 23 is installed in the first mounting groove 22. A second mounting groove 24 is formed circumferentially on the outer wall of the valve body 4 below the outlet port 21, and a second sealing ring 25 is installed in the second mounting groove 24. Both the first sealing ring 23 and the second sealing ring 25 are annular and made of high and low temperature resistant rubber.

[0048] The shape of connector 8 is determined according to the installation requirements. It consists of plastic and metal parts and is installed on the outer wall of the stop 1. The metal plate inside the output end of connector 8 is connected to the enameled wire inside the coil 3. The input end is connected to the external power supply. The input end of connector 8 is controlled by PWM signal.

[0049] Combination Figure 2To further illustrate the present invention, when the solenoid valve of the present invention is not energized, the elastic component 14 presses the steel ball 7 against the upper edge of the second through hole 17 of the valve seat 6 through the armature 4 and the push rod 5, the oil inlet 30 and the oil outlet 21 are closed, the oil outlet 21 and the oil return port 20 are connected, and the solenoid valve relieves the pressure at the oil outlet 21.

[0050] When energized, the armature 4 moves upward under the action of electromagnetic force, compressing the elastic component 14. The steel ball 7 is pressed against the lower edge of the inner hole of the limiting boss 15 under the action of liquid pressure at the oil inlet 30. The oil outlet 21 and the oil return 20 are connected, and the oil inlet 30 and the oil outlet 21 are connected. The oil inlet 30 supplies liquid to the oil outlet 21.

[0051] Due to the structural advantages of solenoid valves, they have opening and closing speeds within 5ms. PWM signals can be used to achieve high-speed continuous opening and closing of the solenoid valve. Utilizing the characteristic that the duty cycle of the PWM signal corresponds to the high-level time, the duty cycle is used to control the time for liquid to be supplied from the inlet 30 to the outlet 21 after the solenoid valve is opened. Simultaneously, utilizing the characteristic that the duty cycle of the PWM signal corresponds to the low-level time, the duty cycle is used to control the release time of the solenoid valve. This controls the time for the outlet 21 to release pressure through the return port 20 when the solenoid valve is closed, thus achieving simultaneous regulation of the pressure and flow rate at the outlet 21.

Claims

1. A normally closed two-position three-way PWM solenoid valve with a non-magnetic gasket ball valve structure, comprising a stop (1), an armature (2), a coil (3), a valve body (4), a push rod (5), a valve seat (6), a steel ball (7), a connector (8), and an elastic component (14); characterized in that: The stop (1) is a hollow cylinder with an open bottom. The inner surface of the top of the stop (1) is provided with a cylindrical boss (9) and a countersunk hole (10) is provided at the bottom of the boss (9). The armature (2) is coated with a non-magnetic coating and is coaxially arranged with the boss (9). The top of the armature (2) is provided with a first mounting hole (11) and the bottom is provided with a second mounting hole (12). The first mounting hole (11) and the second mounting hole (12) are connected through a connecting hole (13). The diameter of the connecting hole (13) is smaller than that of the first mounting hole (11). The first mounting hole (11), the second mounting hole (12), the connecting hole (13) and the countersunk hole (10) are coaxially arranged. One end of the elastic member (14) abuts or connects with the bottom of the countersunk hole (10), and the other end abuts or connects with the bottom of the first mounting hole (11); The coil (3) is wound around the upper part of the armature (2) and the outer wall of the boss (9), and is located between the outer wall of the boss (9) and the inner wall of the stop (1); One end of the top rod (5) is fixedly installed in the second mounting hole (12), and the other end is set opposite to the steel ball (7); The valve body (4) has a first through hole (16) axially opened inside, which is sleeved on the lower outer side of the armature (2). The inner wall of the first through hole (16) is provided with a limiting boss (15). The valve body (4) is located below the armature (2) and has an oil return port (20) that communicates with the first through hole (16) radially opened. The valve seat (6) is fixed to the bottom of the first through hole (16), and a cavity (19) is formed between the top of the valve seat (6) and the limiting boss (15). The steel ball (7) is located in the cavity (19), and the height of the cavity (19) allows the steel ball (7) to move axially within the cavity (19). The valve seat (6) is provided with a channel for connecting the bottom end of the first through hole (16) and the cavity (19). The valve body (4) is provided with an oil outlet (21) that communicates with the cavity (19) in the radial direction at the cavity (19). The coil (3) is connected to an external power supply via a connector (8), and the input terminal of the connector (8) is controlled by a PWM signal.

2. The normally closed two-position three-way PWM solenoid valve with a non-magnetic gasket ball valve structure as described in claim 1, characterized in that: The top rod (5) is provided with a limiting step (31) at one end near the steel ball (7). The limiting step (31) abuts against the upper surface of the limiting boss (15) to limit the displacement of the top rod (5) in the direction of approaching the steel ball (7).

3. The normally closed two-position three-way PWM solenoid valve with a non-magnetic gasket ball valve structure as described in claim 1 or 2, characterized in that: It also includes a mounting plate (18); The mounting plate (18) is radially fixedly connected along the bottom of the stop (1); The outer wall of the valve body (4) is fixedly connected to the inner wall of the mounting plate (18); The lower end of the coil (3) is attached to the mounting plate (18).

4. The normally closed two-position three-way PWM solenoid valve with a non-magnetic gasket ball valve structure as described in claim 3, characterized in that: The valve body (4) has a first mounting groove (22) circumferentially formed on the outer wall between the oil return port (20) and the oil outlet (21) for installing the first sealing ring (23); the valve body (4) has a second mounting groove (24) circumferentially formed on the outer wall below the oil outlet (21) for installing the second sealing ring (25).

5. The normally closed two-position three-way PWM solenoid valve with a non-magnetic gasket ball valve structure as described in claim 4, characterized in that: The bottom of the first through hole (16) is located below the valve seat (6) and a first filter screen (26) is provided. The outer edge of the first filter screen (26) is sealed to the inner wall of the first through hole (16). A second filter (27) is provided at the oil outlet (21).

6. The normally closed two-position three-way PWM solenoid valve with a non-magnetic gasket ball valve structure as described in claim 5, characterized in that: A bearing (28) is installed on the outside of the top rod (5) below the armature (2), and the bearing (28) is installed through a bearing seat (29) fixed in the first through hole (16).

7. The normally closed two-position three-way PWM solenoid valve with a non-magnetic gasket ball valve structure as described in claim 6, characterized in that: The outer wall of the valve seat (6) is fitted and connected to the inner wall of the first through hole (16). A second through hole (17) is provided in the valve seat (6) along the axial direction to connect the bottom end of the first through hole (16) with the cavity (19).

8. The normally closed two-position three-way PWM solenoid valve with a non-magnetic gasket ball valve structure as described in claim 7, characterized in that: The connector (8) is installed on the outer wall of the stop (1). The metal plate inside the output end of the connector (8) is connected to the enameled wire inside the coil (3), and the input end is connected to the external power supply.

Images