Normally closed two-position three-way PWM solenoid valve combined with plate valve and spool valve

Abstract

This invention pertains to a two-position three-way PWM solenoid valve. To address the 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, and significant leakage, this invention provides a normally closed two-position three-way PWM solenoid valve combining a plate valve and a spool valve. The yoke includes an outer yoke and an inner yoke. A mounting plate is located at the bottom of the outer yoke. A coil is wound around the outside of the inner yoke. The inner yoke is fitted around the outside of the armature. The armature is fitted around the top of the valve stem. The valve body is fitted around the outside of the valve stem. The valve body has a return port and an outlet port radially arranged from top to bottom. A valve seat cavity is located on the bottom end face. A sealing boss is located on the inner wall of the valve body below the outlet port. The valve stem has a first step and a second step. The first step mates with the lower inner wall of the return port, and the second step mates with the sealing boss. A countersunk hole is located on the bottom end face of the valve stem, and an elastic component is located within the countersunk hole.

Description

Technical Field

[0001] This invention pertains to two-position three-way PWM solenoid valves, specifically a normally closed two-position three-way PWM solenoid valve that combines a plate valve and a slide valve. Background Technology

[0002] In various hydraulic systems, PWM solenoid valves (pulse width modulation solenoid valves, also known as high-speed switching solenoid valves) can 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, and large leakage between the inlet and outlet, as well as between the outlet and the return port, this invention provides a normally closed two-position three-way PWM solenoid valve consisting of a plate valve and a slide valve combination.

[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 combining a plate valve and a slide valve, comprising a yoke, armature, coil, valve body, valve stem, valve seat, and connector; its special feature is that...

[0008] The yoke includes a hollow columnar outer yoke and a hollow columnar inner yoke. The outer yoke is fitted outside the inner yoke. The top end faces of the outer yoke and the inner yoke are flush and connected. A gap is left between the side walls of the outer yoke and the inner yoke to form a cavity.

[0009] The bottom of the outer yoke is provided with a mounting plate in the radial direction;

[0010] The coil is wound around the outer side of the inner yoke and is located inside the cavity;

[0011] The inner yoke is sleeved on the outside of the armature, and the armature is sleeved on the outside of the top of the valve stem and fixedly connected to the valve stem; the surface of the armature is coated with a non-magnetic coating.

[0012] The valve body is sleeved on the outside of the valve stem, located below the armature, and the outer wall of the valve body is fixedly connected to the inner wall of the mounting plate.

[0013] The valve body is located below the mounting plate and has an oil return port and an oil outlet radially arranged from top to bottom. The bottom end face of the valve body is provided with a valve seat cavity, and the valve seat is set in the valve seat cavity. A channel for oil to pass through is left between the valve seat and the inner wall of the valve seat cavity. A sealing boss is provided on the inner wall of the valve body below the oil outlet.

[0014] The valve stem is provided with a first step and a second step. The first step is used to abut against the lower inner wall of the oil return port, and the second step is used to abut against the sealing boss. A countersunk hole is opened on the bottom end face of the valve stem. An elastic component is provided in the countersunk hole. One end of the elastic component abuts against the bottom of the countersunk hole, and the other end abuts against the valve seat.

[0015] The coil is connected to an external power source via a connector.

[0016] Furthermore, the height of the inner yoke is lower than that of the outer yoke, and a limiting boss is provided on the outer side of the bottom of the armature;

[0017] The limiting boss abuts against the bottom end face of the inner yoke.

[0018] 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.

[0019] Furthermore, a filter screen is provided below the valve seat in the valve seat cavity, and the outer edge of the filter screen is sealed to the inner wall of the valve seat cavity.

[0020] Furthermore, the outer wall of the valve seat is fitted and connected to the inner wall of the valve seat cavity, and the outer wall of the valve seat is provided with multiple oil channels along the circumference, the oil channels penetrating the upper and lower end faces of the valve seat.

[0021] Furthermore, the connector is installed on the outer wall of the yoke, the metal plate inside the connector output end is connected to the enameled wire inside the coil, and the input end is connected to an external power supply.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] 1. The normally closed two-position three-way PWM solenoid valve of the present invention, which combines a plate valve and a slide valve, adopts a plate-type switching valve structure between the oil inlet and the oil outlet by using the second step on the valve stem and the sealing boss on the valve body. The slide valve-type switching valve structure is formed by the first step on the valve stem and the lower side wall of the oil return port on the valve body. It has good sealing performance and long service life.

[0024] 2. In this invention, the bottom outer side of the armature is provided with a limiting boss that can serve as a stop, and the bottom end face of the inner yoke part in the yoke serves as a pole shoe. The magnetic field utilization rate is high, and the solenoid valve's pull-in time and release time are both very small. It has been verified that they can be less than 5ms, and the solenoid valve's action response speed is fast.

[0025] 3. This invention adopts an integral structure, uses fewer parts, and each part is easy to process, making it suitable for mass production.

[0026] 4. 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.

[0027] 5. The oil inlet of this invention is equipped with a filter screen, which can filter the incoming oil, reduce the damage of impurities to the solenoid valve, and effectively improve the service life of the solenoid valve.

[0028] 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

[0029] Figure 1 This is a schematic diagram of an embodiment of the normally closed two-position three-way PWM solenoid valve combining a plate valve and a slide valve according to the present invention.

[0030] Among them, 1-yoke, 101-outer yoke, 102-inner yoke, 2-armature, 3-coil, 4-valve body, 5-valve stem, 6-valve seat, 7-mounting plate, 8-oil return port, 9-oil outlet, 10-first step, 11-second step, 12-valve seat cavity, 13-sealing boss, 14-elastic component, 15-limiting boss, 16-first mounting groove, 17-second mounting groove, 18-filter screen, 19-oil passage, 20-connector, 21-first sealing ring, 22-second sealing ring, 23-oil inlet. Detailed Implementation

[0031] The present invention will now be described in further detail with reference to the accompanying drawings:

[0032] like Figure 1The present invention provides a normally closed two-position three-way PWM solenoid valve consisting of a plate valve and a slide valve, including a yoke 1, an armature 2, a coil 3, a valve body 4, a valve stem 5, a mounting plate 7, a valve seat 6, and a connector 20.

[0033] The yoke 1 is a thin-walled cylindrical shape, comprising a hollow cylindrical outer yoke portion 101 and a hollow cylindrical inner yoke portion 102. The outer yoke portion 101 is fitted over the inner yoke portion 102, and the inner yoke portion 102 is fitted over the outer side of the armature 2. The top ends of the outer yoke portion 101 and the inner yoke portion 102 are flush and connected. The height of the inner yoke portion 102 is lower than that of the outer yoke portion 101, meaning the bottom of the inner yoke portion 102 is lower than that of the outer yoke portion 101. The yoke 101 is shorter. The yoke 1 is made of soft magnetic material. There is a gap between the side walls of the outer yoke 101 and the inner yoke 102 to form a cavity for accommodating the coil 3. The coil 3 is wound around the outside of the inner yoke 102. The coil 3 is made of plastic and enameled wire. The lower part of the coil 3 is attached to the mounting plate 7. The lower end of the outer yoke 101 is riveted to the mounting plate 7. The mounting plate 7 is arranged radially along the bottom of the outer yoke 101.

[0034] The armature 2 is columnar, made of soft magnetic material, with an internal through hole and a non-magnetic coating on its surface. The armature 2 is sleeved on the outer top of the valve stem 5 and is integrated with the valve stem 5. As a preferred embodiment, a limiting boss 15 is provided on the outer bottom of the armature 2. The limiting boss 15 abuts against the bottom end face of the inner yoke 102, thereby limiting the axial displacement of the armature 2 through the bottom end face of the inner yoke 102.

[0035] The valve body 4 is made of metal and is multi-segmented cylindrical. It is fitted outside the valve stem 5 and located below the armature 2. The upper outer wall of the valve body 4 is fixedly connected to the inner wall of the mounting plate 7. Specifically, the valve body 4 is fitted into the semi-circular notch in the mounting plate 6 and is integrated with the mounting plate 6. The valve body 4 has a through hole running from top to bottom. The valve stem 5 is located in the through hole and can move axially relative to the valve body 4. The bottom end face of the valve body 4 has a valve seat cavity 12. The valve seat 6 is located in the valve seat cavity 12 and is fitted and connected to the inner wall of the valve seat cavity 12, forming a whole. The outer wall of the valve seat 6 has multiple oil channels 19 along the circumference. The oil channels 19 penetrate the upper and lower end faces of the valve seat 6 and are used for oil to pass through the oil channels 19. The valve seat 6 is thin and made of metal.

[0036] An oil inlet 23 is formed at the lower opening of the valve seat cavity 12. The valve body 4 is located below the mounting plate 7 and has an oil return port 8 and an oil outlet 9 radially arranged from top to bottom. A sealing boss 13 is also provided on the inner wall of the valve body 4 below the oil outlet 9.

[0037] In addition, a filter screen 18 is provided in the valve seat cavity 12 below the valve seat 6. The outer edge of the filter screen 18 is sealed to the inner wall of the valve seat cavity 12 to prevent oil from passing through the connection between the filter screen 18 and the valve seat cavity 12. The filter screen 18 is a thin-walled cylindrical shape that filters the oil entering from the oil inlet 23. It is made of metal mesh and plastic support through injection molding.

[0038] The valve stem 5 is made of metal and is multi-segmented cylindrical. The valve stem 5 has a first step 10 and a second step 11. The first step 10 abuts against the lower inner wall of the return port 8 when the valve stem 5 moves, forming a return valve port. The second step 11 abuts against the sealing boss 13 when the valve stem 5 moves, forming an inlet valve port. Additionally, a countersunk hole is formed on the bottom end face of the valve stem 5, and an elastic component 14 is installed inside the countersunk hole. One end of the elastic component 14 abuts against the bottom of the countersunk hole, and the other end abuts against the valve seat 6. The elastic component 14 can be a cylindrical compression spring made of metal.

[0039] A first mounting groove 16 is circumferentially formed on the outer wall of the valve body 4 between the oil return port 8 and the oil outlet 9. A first sealing ring 21 is installed in the first mounting groove 16. A second mounting groove 17 is circumferentially formed on the outer wall of the valve body 4 below the oil outlet 9. A second sealing ring 22 is installed in the second mounting groove 17. Both the first sealing ring 21 and the second sealing ring 22 are made of high and low temperature resistant rubber and are respectively installed in the first mounting groove 16 and the second mounting groove 17 on the valve body 4.

[0040] The coil 3 is connected to an external power source via connector 20. The shape of connector 20 is determined according to the installation requirements. It consists of plastic and metal parts and is installed on the outer circular surface of the yoke 1. The internal metal sheet is connected to the enameled wire inside the coil 3.

[0041] The oil inlet formed by the second step 11 on the valve stem 5 and the sealing boss 13 on the valve body 4 constitutes a plate-type switch valve structure between the oil inlet 23 and the oil outlet 9. The oil return valve formed between the first step 10 on the valve stem 5 and the lower inner wall of the oil return port 8 on the valve body 4 constitutes a slide valve-type switch valve structure between the oil outlet 9 and the oil return port 8.

[0042] When the solenoid valve is powered by its rated voltage signal, the opening time is no more than 5ms; when powered off, the closing time is no more than 5ms. Using a PWM signal, the pressure and flow rate at the oil outlet 9 can be adjusted.

[0043] When the normally closed two-position three-way PWM solenoid valve of the plate valve and slide valve combination of the present invention is not energized, the elastic component 14 presses the valve stem 5 tightly against it, and the second step 11 on the valve stem 5 is tightly fitted with the sealing boss 13 on the valve body 4. At this time, the oil passage between the oil inlet 23 and the oil outlet 9 is closed, achieving a seal against the inlet pressure. At the same time, the oil outlet 9 and the oil return port 8 are connected, and the liquid at the oil outlet 9 flows out from the oil return port 8. When energized, the electromagnetic attraction force is greater than the spring force of the elastic component 14, and the valve stem 5 is driven downward by the electromagnetic force to press against the valve seat 9. The second step 11 on the valve stem 5 separates from the sealing boss 13 on the valve body. At this time, the oil passage between the oil inlet 23 and the oil outlet 9 is opened, and at the same time, the oil passage between the oil outlet 9 and the oil return port 8 is closed. The liquid flows through the oil inlet 23 through the interior of the valve body 4 and flows out from the oil outlet 9. Because the oil passage between the return port 8 and the outlet port 9 is closed, only a small amount of leaked liquid flows out of the return port 8 due to the gap between the through hole in the valve body 4 and the valve stem 5.

[0044] When using a PWM signal, the duty cycle is a fixed value D. The high-level time T is obtained by multiplying the duty cycle D by the PWM signal period T. 高 Greater than the solenoid valve pull-in time T 吸合 The solenoid valve in T 高 -T 吸合 During the time period, oil is supplied to outlet 9. During the remaining low-level time T×(1-D)-T 释放 When the solenoid valve resets to the de-energized state, oil outlet 9 discharges oil to return port 8 to relieve pressure. Since the solenoid valve's pull-in and release times are both less than 5ms, by repeating the above PWM signal input to the solenoid valve's on / off action, from a macroscopic perspective, the outlet pressure and the input duty cycle value have an approximately one-to-one linear relationship. Therefore, using a PWM signal, the solenoid valve can regulate the flow and pressure at outlet 9.

Claims

1. A normally closed two-position three-way PWM solenoid valve consisting of a plate valve and a slide valve, comprising a yoke (1), an armature (2), a coil (3), a valve body (4), a valve stem (5), a valve seat (6), and a connector (20); Its features are: The yoke (1) includes a hollow columnar outer yoke part (101) and a hollow columnar inner yoke part (102). The outer yoke part (101) is sleeved outside the inner yoke part (102). The top end faces of the outer yoke part (101) and the inner yoke part (102) are flush and connected. A gap is left between the side walls of the outer yoke part (101) and the inner yoke part (102) to form a cavity. The coil (3) is wound around the outside of the inner yoke (102) and located inside the cavity; The inner yoke (102) is sleeved on the outside of the armature (2); the armature (2) is sleeved on the outside of the top of the valve stem (5) and is fixedly connected to the valve stem (5); the surface of the armature (2) is coated with a non-magnetic coating. The valve body (4) is sleeved on the outside of the valve stem (5) and located below the armature (2); The valve body (4) is provided with an oil return port (8) and an oil outlet (9) radially from top to bottom; the bottom end face of the valve body (4) is provided with a valve seat cavity (12), the valve seat (6) is provided in the valve seat cavity (12), and a channel for oil to pass through is left between the valve seat (6) and the inner wall of the valve seat cavity (12); a sealing boss (13) is provided on the inner wall of the valve body (4) below the oil outlet (9); The valve stem (5) is provided with a first step (10) and a second step (11). The first step (10) is used to abut against the lower inner wall of the oil return port (8), and the second step (11) is used to abut against the sealing boss (13). The bottom end face of the valve stem (5) is provided with a countersunk hole. An elastic component (14) is provided in the countersunk hole. One end of the elastic component (14) abuts against the bottom of the countersunk hole, and the other end abuts against the valve seat (6). The coil (3) is connected to an external power supply via a connector (20), and the input terminal of the connector (20) is controlled by a PWM signal.

2. The normally closed two-position three-way PWM solenoid valve combining a plate valve and a slide valve as described in claim 1, characterized in that: The height of the inner yoke (102) is lower than that of the outer yoke (101), and the bottom outer side of the armature (2) is provided with a limiting boss (15). The limiting boss (15) abuts against the bottom end face of the inner yoke part (102).

3. The normally closed two-position three-way PWM solenoid valve combining a plate valve and a slide valve as described in claim 1 or 2, characterized in that: The bottom of the outer yoke (101) is provided with a mounting plate (7) in the radial direction; the outer wall of the valve body (4) is fixedly connected to the inner wall of the mounting plate (7); the valve body (4) is located below the mounting plate (7).

4. The normally closed two-position three-way PWM solenoid valve combining a plate valve and a slide valve as described in claim 3, characterized in that: The valve body (4) has a first mounting groove (16) circumferentially opened on the outer wall between the oil return port (8) and the oil outlet (9) for installing the first sealing ring (21); the valve body (4) has a second mounting groove (17) circumferentially opened on the outer wall below the oil outlet (9) for installing the second sealing ring (22).

5. The normally closed two-position three-way PWM solenoid valve combining a plate valve and a slide valve as described in claim 4, characterized in that: A filter screen (18) is provided in the valve seat cavity (12) below the valve seat (6), and the outer edge of the filter screen (18) is connected to the inner wall of the valve seat cavity (12).

6. The normally closed two-position three-way PWM solenoid valve combining a plate valve and a slide valve as described in claim 5, characterized in that: The outer wall of the valve seat (6) is fitted and connected to the inner wall of the valve seat cavity (12). The outer wall of the valve seat (6) is provided with multiple oil channels (19) along the circumference. The oil channels (19) penetrate the upper and lower surfaces of the valve seat (6).

7. The normally closed two-position three-way PWM solenoid valve combining a plate valve and a slide valve as described in claim 6, characterized in that: The connector (20) is installed on the outer wall of the yoke (1). The metal plate inside the output end of the connector (20) is connected to the enameled wire inside the coil (3), and the input end is connected to the external power supply.

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