Proportional speed regulating valve

Abstract

The utility model provides a proportional speed regulating valve, which belongs to the technical field of speed regulating valves and comprises a valve body assembly and a pressure valve core, the pressure valve core is movably mounted in a pressure valve hole, and the stroke position of a first plugging part determines the on-off and the sectional area of a fluid channel between a first cavity and a second cavity. The stroke position of the pressure valve core is determined by the pressure of the third cavity; the flow valve element is movably installed in the flow valve hole, and the stroke position of the second blocking part determines the on-off state and the sectional area of a fluid channel between the fifth cavity and the sixth cavity; the hydraulic control valve has the advantages that when the proportional electromagnet is powered on, the second plugging part opens the fluid channel between the fifth cavity and the sixth cavity so that the oil inlet can be communicated with the working oil port, the pressure valve element moves along with the pressure change of the third cavity, and therefore the pressure of the first cavity is adjusted, and the pressure of the second cavity is adjusted. And the pressure difference between the first cavity and the third cavity is kept stable.

Description

Technical Field

[0001] The utility model belongs to the technical field of speed control valves and relates to a proportional speed control valve. Background Art

[0002] A proportional speed control valve is a proportional control valve used to control the flow rate of fluids. This valve can precisely adjust the position of the internal valve core by inputting an electrical signal, thereby controlling the fluid flow rate through the valve. A proportional speed control valve usually consists of a proportional electromagnet and a flow valve. Among them, the proportional electromagnet generates a magnetic force of corresponding magnitude according to the received electrical signal, driving the valve core to move against the elastic force of the spring to achieve continuous adjustment of the flow rate.

[0003] In traditional proportional speed control valves, their flow rate adjustment function is affected by the system pressure difference. Specifically, when the pressure at the load end in the system changes, even if the position of the valve core remains unchanged, the flow rate through the valve will also change accordingly. This phenomenon leads to instability and unpredictability in flow rate control, especially in occasions where high-precision flow rate control is required, and this limitation is particularly prominent, so there is certain room for improvement. Summary of the Utility Model

[0004] The purpose of the utility model is to provide a proportional speed control valve for the above problems existing in the prior art.

[0005] The purpose of the utility model can be achieved by the following technical solutions: A proportional speed control valve, comprising:

[0006] A valve body assembly, the valve body assembly is provided with an oil inlet, an oil return port, a working oil port, a pressure valve hole and a flow valve hole. The pressure valve hole includes a first cavity, a second cavity and a third cavity that are connected in sequence. The flow valve hole includes a fourth cavity, a fifth cavity and a sixth cavity that are connected in sequence. The oil inlet is connected to the first cavity, the oil return port is connected to the second cavity, the working oil port is connected to the third cavity, the first cavity is connected to the fourth cavity, and the sixth cavity is connected to the third cavity;

[0007] A pressure valve core, the pressure valve core is movably installed in the pressure valve hole. The pressure valve core includes a first blocking portion. The first blocking portion can close or open the fluid passage between the first cavity and the second cavity. The first blocking portion blocks the fluid passage between the second cavity and the third cavity. The stroke position of the pressure valve core is determined by the pressure magnitude in the third cavity. The stroke position of the pressure valve core determines the cross-sectional area of the fluid passage between the first cavity and the second cavity;

[0008] Flow control valve spool, the flow control valve spool is movably installed in the flow control valve hole, the flow control valve spool includes a second blocking portion, and the stroke position of the second blocking portion determines the on-off and cross-sectional area of the fluid passage between the fifth cavity and the sixth cavity;

[0009] Proportional electromagnet, the proportional electromagnet is connected to the flow control valve spool, and the magnitude of the current of the proportional electromagnet determines the stroke position of the flow control valve spool;

[0010] When the proportional electromagnet is de-energized, the second blocking portion blocks the fluid passage between the fifth cavity and the sixth cavity to block the fluid path from the oil inlet to the working oil port; when the proportional electromagnet is energized, the second blocking portion opens the fluid passage between the fifth cavity and the sixth cavity to connect the oil inlet and the working oil port.

[0011] Preferably, it further includes an overflow valve spool, the valve body assembly further includes an overflow valve hole, the overflow valve spool is movably installed in the overflow valve hole, the overflow valve hole includes an overflow cavity, the overflow cavity is communicated with the oil return port, the overflow valve spool blocks the fluid passage between the inlet of the overflow valve hole and the overflow cavity, the pressure valve hole further includes a seventh cavity, the seventh cavity is communicated with the inlet of the overflow valve hole, a blind hole is opened at the end of the pressure valve spool, and a side opening communicated with the blind hole is opened on the wall of the pressure valve spool, the side opening is located in the third cavity and the blind hole is communicated with the third cavity, the opening of the blind hole is communicated with the seventh cavity, and when the pressure in the third cavity is greater than the threshold value, the pressure valve spool opens to enable the third cavity to be communicated with the oil return port through the overflow valve hole.

[0012] Preferably, a second spring with adjustable elastic force is installed in the overflow valve hole, the second spring is in contact connection with the overflow valve spool and applies an elastic force to the overflow valve spool to block the fluid passage between the inlet of the overflow valve hole and the overflow cavity, and the elastic force of the second spring determines the magnitude of the threshold value.

[0013] Preferably, the pressures corresponding to both sides of the first blocking portion are the pressure in the first cavity and the pressure in the third cavity respectively.

[0014] Preferably, a first spring is arranged between the end of the pressure valve spool and the valve body assembly, the first spring is in contact connection with the pressure valve spool and applies an elastic force to the pressure valve spool in the direction from the third cavity to the first cavity.

[0015] Preferably, a third spring is arranged between the end of the flow control valve spool and the valve body assembly, and the third spring applies an elastic force to the flow control valve spool in the direction from the sixth valve body to the fourth valve body.

[0016] Preferably, the valve body assembly includes a main valve body and an overflow valve body. The overflow valve body is fixedly connected to the main valve body by screws. The pressure valve hole and the flow valve hole are both opened in the main valve body, and the overflow valve hole is opened in the overflow valve body.

[0017] Preferably, the valve body assembly is further provided with a first detection port and a second detection port. The first detection port communicates with the fourth cavity, and the second detection port communicates with the sixth cavity.

[0018] Compared with the prior art, the beneficial effects of the present utility model are as follows:

[0019] 1. When the proportional electromagnet is energized, the second blocking portion opens the fluid passage between the fifth cavity and the sixth cavity to connect the oil inlet and the working oil port. When the pressure in the third cavity changes, the pressure valve core moves accordingly, thereby adjusting the pressure in the first cavity so that the pressure difference between the first cavity and the third cavity remains stable.

[0020] 2. Since the blind hole on the pressure valve core communicates with the third cavity through the side opening, the opening of the blind hole communicates with the seventh cavity, and the seventh cavity communicates with the overflow valve hole. This means that the third cavity is actually connected to the inlet of the overflow valve hole. Once the pressure in the third cavity (working oil port) exceeds the threshold, the overflow valve core is lifted, and the pressure in the third cavity is stabilized at the set value, thereby playing a role in pressure protection.

[0021] 3. The two detection ports communicate with the fourth cavity and the sixth cavity respectively, enabling the speed control valve to have a built-in pressure detection function. Such a design helps to monitor the key pressure points in the hydraulic system in real time and ensure the normal operation of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic internal structure diagram of the proportional speed control valve of the present utility model.

[0023] Figure 2 It is a schematic connection diagram of the flow valve hole, the flow valve core, the pressure valve hole, the pressure valve core, the overflow valve hole and the overflow valve core of the present utility model.

[0024] Figure 3 It is a schematic internal structure diagram of the valve body assembly of the present utility model.

[0025] Figure 4 It is a schematic structure diagram of the pressure valve core in the pressure valve hole of the present utility model.

[0026] Figure 5 It is an axonometric view of the proportional speed control valve of the present utility model.

[0027] In the figure, 100 is the main valve body; 110 is the oil inlet; 120 is the oil return port; 130 is the working oil port; 140 is the pressure valve hole; 141 is the first cavity; 142 is the second cavity; 143 is the third cavity; 144 is the seventh cavity; 150 is the flow valve hole; 151 is the fourth cavity; 152 is the fifth cavity; 153 is the sixth cavity; 160 is the first detection port; 170 is the second detection port; 200 is the overflow valve body; 210 is the overflow valve hole; 211 is the overflow cavity; 300 is the pressure valve core; 310 is the first blocking part; 320 is the blind hole; 330 is the side opening; 340 is the first spring; 400 is the flow valve core; 410 is the second blocking part; 420 is the third spring; 500 is the overflow valve core; 510 is the second spring; 600 is the proportional electromagnet. Detailed implementation manners

[0028] The following are specific embodiments of the present invention and, in conjunction with the accompanying drawings, further describe the technical solutions of the present invention, but the present invention is not limited to these embodiments.

[0029] As Figures 1-5As shown in the figure, a proportional speed control valve includes: a valve body assembly. The valve body assembly is provided with an oil inlet 110, an oil return port 120, a working oil port 130, a pressure valve hole 140 and a flow valve hole 150. The pressure valve hole 140 includes a first cavity 141, a second cavity 142 and a third cavity 143 that are connected in sequence. The flow valve hole 150 includes a fourth cavity 151, a fifth cavity 152 and a sixth cavity 153 that are connected in sequence. The oil inlet 110 is connected to the first cavity 141, the oil return port 120 is connected to the second cavity 142, the working oil port 130 is connected to the third cavity 143, the first cavity 141 is connected to the fourth cavity 151, and the sixth cavity 153 is connected to the third cavity 143; a pressure valve core 300, which is movably installed in the pressure valve hole 140. The pressure valve core 300 includes a first blocking portion 310. The first blocking portion 310 can close or open the fluid passage between the first cavity 141 and the second cavity 142, and the first blocking portion 310 blocks the fluid passage between the second cavity 142 and the third cavity 143. The stroke position of the pressure valve core 300 is determined by the pressure magnitude in the third cavity 143, and the stroke position of the pressure valve core 300 determines the cross-sectional area of the fluid passage between the first cavity 141 and the second cavity 142; a flow valve core 400, which is movably installed in the flow valve hole 150. The flow valve core 400 includes a second blocking portion 410. The stroke position of the second blocking portion 410 determines the on / off and cross-sectional area of the fluid passage between the fifth cavity 152 and the sixth cavity 153; a proportional electromagnet 600, which is connected to the flow valve core 400. The magnitude of the current of the proportional electromagnet 600 determines the stroke position of the flow valve core 400; when the proportional electromagnet 600 is de-energized, the second blocking portion 410 blocks the fluid passage between the fifth cavity 152 and the sixth cavity 153 to block the fluid path from the oil inlet 110 to the working oil port 130; when the proportional electromagnet 600 is energized, the second blocking portion 410 opens the fluid passage between the fifth cavity 152 and the sixth cavity 153 to connect the oil inlet 110 and the working oil port 130.

[0030] The oil inlet 110 is the entrance for the oil fluid to enter the speed control valve from the oil pump, the oil return port 120 is the exit for the oil fluid to return to the oil tank, and the working oil port 130 is the exit for the oil fluid to lead to the actuator; the pressure valve core 300 is installed in the pressure valve hole 140 and can move axially along the hole. A part of the first blocking portion 310 on the pressure valve core 300 is located at the intersection of the first cavity 141 and the second cavity 142 and can control the on-off of the fluid passage between the two. Another part of the first blocking portion 310 always isolates the fluid passage between the second cavity 142 and the third cavity 143. The pressure valve core 300 can move itself to cut off or open the fluid passage between the first cavity 141 and the second cavity 142 through the first blocking portion 310, and the stroke position of the pressure valve core 300 is actually determined by the pressure difference on both sides of the first blocking portion 310. Specifically, one side of the first blocking portion 310 corresponds to the first cavity 141 and the other side corresponds to the third cavity 143. The pressure in the first cavity 141 is fixed, so in the actual structure, the stroke position of the pressure valve core 300 is determined by the pressure magnitude in the third cavity 143. The pressure magnitude in the third cavity 143 determines the position of the pressure valve core 300, so that the pressure at the oil inlet 110 changes with the change of the pressure at the working oil port 130 to ensure that the flow regulation is not affected by the pressure difference between the oil inlet 110 and the working oil port 130.

[0031] In terms of the principle of adjusting the pressure difference: the movement of the pressure valve core 300 is realized by the pressure difference on both sides of the first blocking portion 310; the pressure in the first cavity 141 can be regarded as equal to the pressure at the oil inlet 110, and the pressure in the third cavity 143 can be regarded as equal to the pressure at the working oil port 130. The forces on both sides of the first blocking portion 310 must be equal. Among them, the pressure on one side of the first blocking portion 310 is the pressure in the first cavity 141 (oil inlet 110), and the pressure on the other side of the first blocking portion 310 is the pressure in the third cavity 143 (working oil port 130) plus the elastic force of the first spring 340. During the working process, the pressure value in the first cavity 141 is equal to the sum value of the pressure value in the third cavity 143 plus the elastic force of the first spring 340. If they are not equal, the pressure valve core 300 will move to make the force values on both sides of the first blocking portion 310 equal, that is, the existence of the pressure valve core 300 makes the pressure difference between the first cavity 141 and the third cavity 143 constant.

[0032] The pressure spool 300 can perform dynamic adjustment to balance the pressure difference under working conditions. Since the pressure at the oil inlet 110 can be defaulted to a fixed value, this means that when the pressure value at the working oil port 130 (the third cavity 143) changes, the pressure at the oil inlet 110 (the first cavity 141) changes accordingly. For example, when the pressure in the third cavity 143 decreases, the force value on the other side of the first sealing portion 310 decreases, and the balance is broken at this time. The first sealing portion 310 moves to increase the cross-sectional area of the fluid passage between the first cavity 141 and the second cavity 142. The pressure in the first cavity 141 decreases so that the pressure difference between the first cavity 141 and the third cavity 143 is restored to the set value. Moreover, the lower the pressure value in the third cavity 143, the greater the opening amplitude of the first sealing portion 310, the greater the flow rate from the first cavity 141 to the second cavity 142, and the lower the pressure in the first cavity 141. If the pressure value in the third cavity 143 rises again, then the opening amplitude of the first sealing portion 310 gradually decreases, so that the pressure value in the first cavity 141 increases. Therefore, the pressure difference between the first cavity 141 and the third cavity 143 remains constant during the entire adjustment process. In addition, when the pressure value in the third cavity 143 reaches the threshold, the first sealing portion 310 reseals the fluid passage between the first cavity 141 and the second cavity 142.

[0033] The flow spool 400 is installed in the flow valve hole 150 and can also move along the axial direction of the hole. The flow spool 400 includes a second sealing portion 410, whose function is to control the opening and closing and the flow area of the fluid passage between the fifth cavity 152 and the sixth cavity 153 according to the position, thereby adjusting the flow rate of the oil. The stroke position of the flow spool 400 is determined by the magnitude of the current of the proportional electromagnet 600 connected thereto. The proportional electromagnet 600 adjusts the position of the flow spool 400 by changing the current, so as to accurately control the flow rate of the oil.

[0034] The specific working principle of the proportional speed control valve is as follows: The hydraulic oil enters the first cavity 141 from the oil inlet 110, and then enters the fourth cavity 151. The proportional electromagnet 600 pushes the flow control valve core 400 to move so that the second blocking part 410 opens the fluid passage between the fifth cavity 152 and the sixth cavity 153. Therefore, the hydraulic oil can enter the sixth cavity 153 through the fifth cavity 152, then enter the third cavity 143 from the sixth cavity 153, and finally flow from the third cavity 143 to the actuator through the working oil port 130; during this process, the flow control valve core 400 can be controlled through the proportional solenoid valve, so as to control the stroke position of the second blocking part 410, and further control the flow rate; when the pressure at the working oil port 130 changes, the pressure control valve core 300 moves accordingly to adjust the cross-sectional area of the fluid passage between the first cavity 141 and the second cavity 142. The differential pressure adjustment process is a dynamic balance adjustment, so that the pressure in the first cavity 141 can change with the pressure change in the third cavity 143, that is, when the pressure in the third cavity 143 decreases, the pressure in the first cavity 141 decreases accordingly, and when the pressure in the third cavity 143 increases, the pressure in the first cavity 141 increases, to ensure that the flow rate adjustment is not affected by the differential pressure.

[0035] As Figures 1-5 shown, on the basis of the above embodiment, an overflow valve core 500 is further included. The valve body assembly further includes an overflow valve hole 210. The overflow valve core 500 is movably installed in the overflow valve hole 210. The overflow valve hole 210 includes an overflow chamber 211. The overflow chamber 211 is communicated with the oil return port 120. The overflow valve core 500 blocks the fluid passage between the inlet of the overflow valve hole 210 and the overflow chamber 211. The pressure valve hole 140 further includes a seventh cavity 144. The seventh cavity 144 is communicated with the inlet of the overflow valve hole 210. A blind hole 320 is opened at the end of the pressure control valve core 300, and a side opening 330 communicated with the blind hole 320 is opened on the wall of the pressure control valve core 300. The side opening 330 is located in the third cavity 143 and the blind hole 320 is communicated with the third cavity 143. The opening of the blind hole 320 is communicated with the seventh cavity 144. When the pressure in the third cavity 143 is greater than the threshold value, the pressure control valve core 300 opens to enable the third cavity 143 to be communicated with the oil return port 120 through the overflow valve hole 210.

[0036] The overflow valve hole 210 is a specially designed passage for installing the overflow valve spool 500, thus playing a role in protecting the pressure of the working oil port 130. The overflow valve hole 210 includes an overflow chamber 211, which is directly connected to the oil return port 120 to guide the excess oil back to the fuel tank when necessary. The overflow valve spool 500 can move within the overflow valve hole 210, and its main function is to cut off the fluid passage between the inlet of the overflow valve hole 210 and the overflow chamber 211. When the pressure in the third chamber 143 exceeds the predetermined safety limit, the overflow valve spool 500 will be pushed open, allowing the excess oil to flow from the inlet of the overflow valve hole 210 into the overflow chamber 211, and then return to the fuel tank through the oil return port 120, thereby reducing the pressure in the third chamber 143 (working oil port 130), thus playing a role in pressure protection.

[0037] Since the blind hole 320 on the pressure valve spool 300 is connected to the third chamber 143 through the side opening 330, and the opening of the blind hole 320 is connected to the seventh chamber 144, and the seventh chamber 144 is connected to the overflow valve hole 210, this means that the third chamber 143 is actually connected to the inlet of the overflow valve hole 210. Once the pressure in the third chamber 143 (working oil port 130) exceeds the threshold value, the overflow valve spool 500 is lifted, and part of the pressure in the third chamber 143 is discharged to the oil return port 120 through the overflow chamber 211, thus playing a role in pressure protection.

[0038] On the basis of the above embodiment, a second spring 510 with adjustable elastic force is installed in the overflow valve hole 210. The second spring 510 is in contact connection with the overflow valve spool 500 and applies an elastic force to the overflow valve spool 500 to cut off the inlet of the overflow valve hole 210 and the overflow chamber 211. The elastic force of the second spring 510 determines the size of the threshold value.

[0039] The overflow valve spool 500, the overflow valve hole 210, the second spring 510, the adjusting bolt and part of the valve body constitute an overflow valve. By adjusting the bolt, the pre-tightening force of the second spring 510 can be adjusted, thereby adjusting the size of the threshold value.

[0040] On the basis of the above embodiment, the pressures corresponding to both sides of the first plugging portion 310 are the pressure in the first chamber 141 and the pressure in the third chamber 143 respectively. This embodiment ensures that the pressure valve spool 300 can adjust the flow of oil according to the change of the pressure difference between these two chambers.

[0041] On the basis of the above embodiment, a first spring 340 is arranged between the end of the pressure valve spool 300 and the valve body assembly. The first spring 340 is in contact connection with the pressure valve spool 300 and applies an elastic force to the pressure valve spool 300 in the direction from the third chamber 143 to the first chamber 141.

[0042] It should be noted here that the acting forces on both sides of the first plugging member are F1 and F2 respectively. Among them, F1 is the pressure P1 in the first cavity 141, and F2 is the sum of the pressure P2 in the third cavity 143 and the elastic force N of the first spring 340. When the pressure valve core 300 is stationary, P1 = P2 + N; when P2 decreases, the pressure valve core 300 moves to make P1 decrease; when P2 increases, the pressure valve core 300 moves to make P1 increase.

[0043] On the basis of the above embodiment, a third spring 420 is provided between the end of the flow valve core 400 and the valve body assembly. The third spring 420 exerts an elastic force on the flow valve core 400 in the direction from the sixth valve body to the fourth valve body.

[0044] When the proportional electromagnet 600 is de-energized, the elastic force of the third spring 420 will cause the flow valve core 400 to move towards the fourth cavity 151. At this time, the second plugging portion 410 will block the fluid passage between the fifth cavity 152 and the sixth cavity 153, interrupting the fluid path from the oil inlet 110 to the working oil port 130. When the proportional electromagnet 600 is energized, a magnetic field will be generated to push the flow valve core 400 towards the sixth cavity 153. Since the acting force exerted by the proportional electromagnet 600 on the flow valve core 400 needs to be equal to the elastic force provided by the third spring 420 to the flow valve core 400, this means that the current magnitude of the proportional electromagnet 600 determines the stroke position of the flow valve core 400, thereby precisely controlling the opening degree of the fluid passage between the fifth cavity 152 and the sixth cavity 153 and regulating the oil flow rate.

[0045] On the basis of the above embodiment, the valve body assembly includes a main valve body 100 and an overflow valve body 200. The overflow valve body 200 is fixedly connected to the main valve body 100 by screws. The pressure valve hole 140 and the flow valve hole 150 are both opened in the main valve body 100, and the overflow valve hole 210 is opened in the overflow valve body 200.

[0046] This design simplifies the manufacturing and assembly process and improves the reliability and maintainability of the system by separately manufacturing the main valve body 100 and the overflow valve body 200 and fixedly connecting them with screws. The main valve body 100 is responsible for pressure control and flow control, while the overflow valve body 200 is responsible for overpressure protection. This modular design makes the functions of each part more clear, facilitating debugging and maintenance.

[0047] Such as Figures 1-3As shown, on the basis of the above embodiments, the valve body assembly is further provided with a first detection port 160 and a second detection port 170. The first detection port 160 communicates with the fourth cavity 151, and the second detection port 170 communicates with the sixth cavity 153. These two detection ports communicate with the fourth cavity 151 and the sixth cavity 153 respectively, enabling the speed control valve to have a built-in pressure detection function. Such a design helps to monitor the key pressure points in the hydraulic system in real time and ensure the normal operation of the system.

[0048] It should be noted that all directional indications (such as up, down, left, right, front, back...) in the embodiments of the present invention are only used to explain the relative positional relationship and movement conditions between components in a specific posture (as shown in the drawings). If this specific posture changes, the directional indications will also change accordingly.

[0049] In addition, in the present invention, descriptions such as "first", "second", and "one" are only for descriptive purposes and should not be construed as indicating or implying their relative importance or implicitly indicating the quantity of the indicated technical features. Thus, features defined as "first" and "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, the meaning of "a plurality" is at least two, such as two, three, etc., unless otherwise specifically defined.

[0050] In the present invention, unless otherwise clearly defined and limited, terms such as "connection" and "fixation" should be understood in a broad sense. For example, "fixation" can be a fixed connection, a detachable connection, or integrated; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two components or the interaction relationship between two components, unless otherwise clearly limited. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0051] In addition, the technical solutions between various embodiments of the present invention can be combined with each other, but it must be based on the ability of those of ordinary skill in the art to implement. When the combination of technical solutions results in contradictions or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the protection scope required by the present invention.

Claims

1. A proportional speed control valve, characterized in that, Comprising: A valve body assembly, the valve body assembly is provided with an oil inlet (110), an oil return port (120), a working oil port (130), a pressure valve hole (140) and a flow valve hole (150), the pressure valve hole (140) includes a first cavity (141), a second cavity (142) and a third cavity (143) that are connected in sequence, the flow valve hole (150) includes a fourth cavity (151), a fifth cavity (152) and a sixth cavity (153) that are connected in sequence, the oil inlet (110) is communicated with the first cavity (141), the oil return port (120) is communicated with the second cavity (142), the working oil port (130) is communicated with the third cavity (143), the first cavity (141) is communicated with the fourth cavity (151), and the sixth cavity (153) is communicated with the third cavity (143); A pressure valve core (300), the pressure valve core (300) is movably installed in the pressure valve hole (140), the pressure valve core (300) includes a first blocking portion (310), the first blocking portion (310) can close or open the fluid passage between the first cavity (141) and the second cavity (142), the first blocking portion (310) blocks the fluid passage between the second cavity (142) and the third cavity (143), the stroke position of the pressure valve core (300) is determined by the pressure magnitude of the third cavity (143), and the stroke position of the pressure valve core (300) determines the cross-sectional area of the fluid passage between the first cavity (141) and the second cavity (142); A flow valve core (400), the flow valve core (400) is movably installed in the flow valve hole (150), the flow valve core (400) includes a second blocking portion (410), and the stroke position of the second blocking portion (410) determines the on-off and cross-sectional area of the fluid passage between the fifth cavity (152) and the sixth cavity (153); A proportional electromagnet (600), the proportional electromagnet (600) is connected to the flow valve core (400), and the magnitude of the current of the proportional electromagnet (600) determines the stroke position of the flow valve core (400); When the proportional electromagnet (600) is powered off, the second blocking portion (410) seals the fluid passage between the fifth cavity (152) and the sixth cavity (153) to block the fluid path from the oil inlet (110) to the working oil port (130); when the proportional electromagnet (600) is powered on, the second blocking portion (410) opens the fluid passage between the fifth cavity (152) and the sixth cavity (153) to connect the oil inlet (110) and the working oil port (130).

2. The proportional speed control valve according to claim 1, characterized in that: It further includes an overflow valve core (500). The valve body assembly further includes an overflow valve hole (210). The overflow valve core (500) is movably installed in the overflow valve hole (210). The overflow valve hole (210) includes an overflow chamber (211). The overflow chamber (211) is communicated with the oil return port (120). The overflow valve core (500) cuts off the fluid passage between the inlet of the overflow valve hole (210) and the overflow chamber (211). The pressure valve hole (140) further includes a seventh chamber (144). The seventh chamber (144) is communicated with the inlet of the overflow valve hole (210). A blind hole (320) is formed at the end of the pressure valve core (300), and a side opening (330) communicated with the blind hole (320) is formed in the wall of the pressure valve core (300). The side opening (330) is located in the third chamber (143) and the blind hole (320) is communicated with the third chamber (143). The opening of the blind hole (320) is communicated with the seventh chamber (144). When the pressure in the third chamber (143) is greater than the threshold value, the pressure valve core (300) opens to enable the third chamber (143) to be communicated with the oil return port (120) through the overflow valve hole (210).

3. The proportional speed control valve according to claim 2, characterized in that: A second spring (510) with adjustable elastic force is installed in the overflow valve hole (210). The second spring (510) is in contact connection with the overflow valve core (500) and applies an elastic force to the overflow valve core (500) to cut off the fluid passage between the inlet of the overflow valve hole (210) and the overflow chamber (211). The elastic force of the second spring (510) determines the magnitude of the threshold value.

4. A proportional speed control valve according to claim 1, characterized in that: The pressures corresponding to both sides of the first plugging portion (310) are respectively the pressure in the first chamber (141) and the pressure in the third chamber (143).

5. The proportional speed control valve according to claim 4, characterized in that: A first spring (340) is arranged between the end of the pressure valve core (300) and the valve body assembly. The first spring (340) is in contact connection with the pressure valve core (300) and applies an elastic force to the pressure valve core (300) in the direction from the third chamber (143) to the first chamber (141).

6. The proportional speed control valve according to claim 1, characterized in that: A third spring (420) is arranged between the end of the flow valve core (400) and the valve body assembly. The third spring (420) applies an elastic force to the flow valve core (400) in the direction from the sixth valve body to the fourth valve body.

7. A proportional speed control valve according to claim 2 or 3, characterized in that: The valve body assembly includes a main valve body (100) and an overflow valve body (200). The overflow valve body (200) is fixedly connected to the main valve body (100) by screws. The pressure valve hole (140) and the flow valve hole (150) are both formed in the main valve body (100). The overflow valve hole (210) is formed in the overflow valve body (200).

8. The proportional speed control valve according to claim 1, characterized in that: The valve body assembly is further provided with a first detection port (160) and a second detection port (170). The first detection port (160) communicates with the fourth cavity (151), and the second detection port (170) communicates with the sixth cavity (153).

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