Backflow prevention device of hydraulic valve

Abstract

The hydraulic valve backflow prevention device comprises a hydraulic valve body and a first oil pipe, the hydraulic valve body comprises a valve body, an oil way switching inner core is arranged in the valve body, two main oil ways are arranged in the oil way switching inner core, and one-way flow limiting rotary cores are arranged at the positions, located at four ports of the two main oil ways, of the oil way switching inner core. In the telescopic operation of the rod of the hydraulic cylinder, in the process that hydraulic oil enters the hydraulic cylinder, one-way oil inlet of the oil is achieved under the action of the one-way flow limiting core, and therefore the situation that the push rod retreats due to thrust reduction and thrust instability caused by backflow of the hydraulic oil is avoided; in the oil way switching process, due to the fact that the rotating speed of the rotating core body is higher than that of the oil way switching inner core, the oil cut-off speed of a channel between a one-way flow channel in the rotating core body and a main oil way is higher than that of channels between the main oil way and a first oil connector, a second oil connector, a third oil connector and a fourth oil connector; and the stability of oil pressure in the oil way switching process is further ensured.

Description

Technical Field

[0001] The invention relates to the technical field of hydraulic oil valves, and in particular to a hydraulic valve backflow prevention device. Background Art

[0002] A hydraulic valve is an automated component operated by pressurized oil. Depending on the situation and the purpose of the hydraulic valve, hydraulic valves can be divided into many categories. Therefore, in real life, hydraulic valves are widely used.

[0003] For example, the application number CN201310463167.7 discloses a hydraulically driven guide rod slider type vibrating peanut harvesting device, including a grabbing component assembly, a lifting vibration component, a lifting component, a hydraulic cylinder assembly and a control component. The hydraulic cylinder assembly includes a driving hydraulic cylinder, an oil circuit and a hydraulic valve; the control component can control the hydraulic valve according to the signal of the sensor, thereby controlling the oil inlet and oil return of the upper oil circuit and the lower oil circuit respectively to realize the extension and retraction of the piston rod of the driving hydraulic cylinder. In actual application, the traditional hydraulic valve of the device is usually only used to control the switching oil circuit. If the hydraulic oil has a reflux phenomenon, it is easy to cause insufficient and unstable push and pull force of the driving hydraulic cylinder. If a one-way oil valve is installed in the oil circuit, it is necessary to increase the interface and oil circuit of the oil chamber in and out of the driving hydraulic cylinder, which increases the equipment assembly steps. Summary of the invention

[0004] In order to solve the above problems, the present invention proposes a hydraulic valve backflow prevention device to more accurately solve the above problems.

[0005] The present invention is achieved through the following technical solutions: The present invention proposes a hydraulic valve backflow prevention device, comprising a hydraulic valve body and a first oil pipe, the hydraulic valve body comprising a valve body, an oil circuit switching circular cavity is arranged inside the valve body, an oil circuit switching inner core is matched and connected in the oil circuit switching circular cavity, a first oil interface is arranged on the top of the valve body, the first oil interface is connected to a first oil pipe, a second oil interface is arranged on one side of the valve body, the second oil interface is connected to a second oil pipe, and the other end of the second oil pipe is connected to a first oil port of a hydraulic cylinder of a hydraulic cylinder, a third oil interface is arranged on the other side of the valve body, the third oil interface is connected to a third oil pipe , and the other end of the third oil pipe is connected to the second oil port of the hydraulic cylinder of the hydraulic cylinder, a fourth oil interface is provided at the bottom of the valve body, and the fourth oil interface is connected to the fourth oil pipe, and two main oil channels in an "L" shape are opened inside the oil circuit switching inner core, a side valve cover is provided on one side of the valve body, and a switching motor is provided on the outer wall of the side valve cover, and a spline shaft rod is provided on the output shaft end of the switching motor, and a spline shaft hole that is matched with the spline shaft rod for transmission connection is provided on one side of the valve body, and a one-way current limiting rotating core is provided at the four port positions of the oil circuit switching inner core and the two main oil channels.

[0006] Furthermore, the first oil interface, the second oil interface, the third oil interface and the fourth oil interface are arranged in a circular array at intervals of 90 degrees, and the four ports of the two main oil channels in the oil circuit switching core are arranged in a circular array at intervals of 90 degrees.

[0007] Furthermore, the one-way flow limiting rotor includes a rotor body, a one-way flow channel for connecting to the main oil channel is opened in the middle of the rotor body, a one-way flow limiting inner cavity is provided in the middle of the one-way flow channel, a top block is provided at one end of the one-way flow limiting inner cavity for pressing, and a limiting flow spring is provided between the top block and the inner cavity of the one-way flow limiting inner cavity.

[0008] Furthermore, a transmission chamber is provided inside the valve body and on one side of the oil circuit switching inner core, an internal gear is integrally formed on the inner wall of the transmission chamber, and planetary gears are provided on one side of the four rotating core bodies, and the planetary gears are meshed with the internal gears.

[0009] Furthermore, the rotating core body is connected to the inside of the oil circuit switching inner core, and the ratio of the number of teeth of the planetary gear to the number of teeth of the internal gear is 1:8.

[0010] Four groups of pressure relief components are arranged inside the valve body, and the four groups of pressure relief components are arranged alternately with the first oil interface, the second oil interface, the third oil interface and the fourth oil interface of the valve body and are arranged at intervals of 45 degrees.

[0011] Furthermore, the pressure-relief component includes a pressure-relief inner cavity opened inside the valve body, a pressure-relief oil hole is opened at one end of the pressure-relief inner cavity close to the oil circuit switching inner core, a piston is slidingly arranged inside the pressure-relief oil hole, a pressure plate is also provided inside the pressure-relief component, and an elastic telescopic rod is connected between the pressure plate and the piston, a pressure-relief oil channel is connected to the two main oil channels inside the oil circuit switching inner core, and the other end of the pressure-relief oil channel extends to correspond to the opening position of the pressure-relief oil hole.

[0012] Furthermore, a pressure regulating bolt is threadedly connected along the outside of the valve body, the axial direction of the pressure regulating bolt is consistent with the axial direction of the pressure relief cavity, and the inner end of the pressure regulating bolt is in conflict with the pressure plate.

[0013] Beneficial effects of the present invention: 1. The present invention allows hydraulic oil to enter along the first oil interface, and is led out along the second oil interface through the main oil channel, and the hydraulic oil enters along the first oil port of the hydraulic cylinder through the second oil pipe, so that the hydraulic cylinder can realize the push rod operation; the oil circuit switching inner core is driven to rotate 90 degrees by the circuit switching motor, and the hydraulic oil enters along the first oil interface, and is led out along the third oil interface through the main oil channel, and the hydraulic oil enters along the second oil port of the hydraulic cylinder through the third oil pipe, so that the hydraulic cylinder can realize the rod retraction operation. By rotating the oil circuit, the extension and retraction of the oil cylinder can be controlled without adding oil circuits and interfaces; 2. In the rod extension and retraction operation of the hydraulic cylinder of the present invention, during the process of the hydraulic oil entering the interior of the hydraulic cylinder, the oil realizes unidirectional oil inflow under the action of the unidirectional flow-limiting rotating core, thereby avoiding the situation in which the thrust is reduced and the push rod retreats due to the thrust instability caused by the reflux of the hydraulic oil; at the same time, under the meshing transmission of the internal gear and the planetary gear arranged on one side of the rotating core body, the rotating core body can rotate with the rotation of the oil circuit switching inner core. In the process of switching the oil circuit, since the rotation speed of the rotating core body is faster than the rotation speed of the oil circuit switching inner core, the oil cut-off speed of the channel between the unidirectional flow channel in the rotating core body and the main oil channel is faster than the oil cut-off speed of the channel between the main oil channel and the first oil interface, the second oil interface, the third oil interface and the fourth oil interface, thereby further ensuring the stability of the oil pressure in the process of switching the oil circuit; 3. During the oil intake process of the present invention, when the oil pressure in the oil circuit is too high, the hydraulic oil enters the pressure relief cavity along the pressure relief oil channel, and the hydraulic oil pushes the piston to compress the elastic telescopic rod, thereby achieving the effect of oil circuit pressure relief, maintaining the oil pressure stable and protecting the oil circuit; the present invention can adjust the hydraulic oil buffer oil pressure by rotating the pressure regulating bolt to adjust the elastic force of the elastic telescopic rod. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a partial cross-sectional view of the three-dimensional structure of the present invention; Figure 2 It is a schematic diagram of the three-dimensional structure of the present invention; Figure 3 It is a disassembled diagram of the first three-dimensional structure of the present invention; Figure 4 It is a disassembled diagram of a second three-dimensional structure of the present invention; Figure 5 for Figure 4 The enlarged view of point A in the middle; Figure 6 for Figure 4 The enlarged view of point B in the middle; Figure 7 It is a structural cross-sectional view of the transmission chamber of the present invention; Figure 8 It is a schematic diagram of the operation of the hydraulic cylinder push rod in the present invention; Fig. 9 It is a working schematic diagram of the hydraulic cylinder when the rod is retracted in the present invention.

[0015] In the figure: 1. Hydraulic valve body; 101. Valve body; 1011. First oil interface; 1012. Second oil interface; 1013. Third oil interface; 1014. Fourth oil interface; 102. Oil circuit switching inner core; 1021. Main oil channel; 1022. Pressure relief oil channel; 103. Side valve cover; 104. One-way flow limiting rotating core; 1041. Rotating core body; 1042. One-way flow channel; 1043. One-way flow limiting inner cavity; 1044. Top block; 1045. Current limiting spring; 105. Transmission chamber; 1051. Inner Gear; 1052, planetary gear; 1053, spline shaft hole; 106, circuit-changing motor; 1061, spline shaft rod; 107, pressure relief assembly; 1071, pressure relief inner cavity; 1072, pressure relief oil hole; 1073, piston; 1074, pressure plate; 1075, elastic telescopic rod; 1076, pressure regulating bolt; 2, first oil pipe; 201, second oil pipe; 202, third oil pipe; 203, fourth oil pipe; 3, hydraulic cylinder; 301, first oil port of hydraulic cylinder; 302, second oil port of hydraulic cylinder. DETAILED DESCRIPTION

[0016] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention. Example

[0017] A hydraulic valve backflow prevention device comprises a hydraulic valve body 1 and a first oil pipe 2, Figure 1 and Figure 8 As shown, the hydraulic valve body 1 includes a valve body 101, an oil circuit switching circular cavity is provided inside the valve body 101, an oil circuit switching inner core 102 is adapted to be connected in the oil circuit switching circular cavity, a first oil interface 1011 is provided on the top of the valve body 101, the first oil interface 1011 is connected to a first oil pipe 2, the first oil pipe 2 is used to connect a hydraulic oil pump to provide hydraulic oil, a second oil interface 1012 is provided on one side of the valve body 101, the second oil interface 1012 is connected to a second oil pipe 201, and the other end of the second oil pipe 201 is connected to the first end of the hydraulic cylinder 3. The third oil pipe 202 is connected to the third oil port 302 of the hydraulic cylinder 3, and the other end of the third oil pipe 202 is connected to the second oil port 302 of the hydraulic cylinder 3, which is used for the oil inlet and outlet when the hydraulic cylinder 3 is telescopic. A fourth oil interface 1014 is provided at the bottom of the valve body 101, and the fourth oil interface 1014 is connected to the fourth oil pipe 203. The fourth oil pipe 203 is used to introduce the hydraulic oil into the oil tank when the hydraulic cylinder 3 is telescopic, so as to provide circulating oil supply for the hydraulic oil pump.

[0018] Two main oil passages 1021 in an "L" shape are provided inside the oil circuit switching inner core 102. The first oil interface 1011, the second oil interface 1012, the third oil interface 1013 and the fourth oil interface 1014 are arranged in a circular array at intervals of 90 degrees. The four ports of the two main oil passages 1021 in the oil circuit switching inner core 102 are arranged in a circular array at intervals of 90 degrees. A side valve cover 103 is provided on one side of the valve body 101. A switching motor 106 is provided on the outer wall of the side valve cover 103. A spline shaft portion 1061 is provided on the output shaft end of the switching motor 106. A spline shaft hole 1053 that is matched with the spline shaft portion 1061 for transmission connection is provided on one side of the valve body 101. Figure 8 As shown, the hydraulic oil enters along the first oil interface 1011, and is led out along the second oil interface 1012 through the main oil channel 1021, and the hydraulic oil enters along the first oil port 301 of the hydraulic cylinder 3 through the second oil pipe 201, so that the hydraulic cylinder 3 can realize the push rod operation, and the hydraulic oil in the internal oil chamber of the first oil port 301 of the hydraulic cylinder is introduced to the third oil interface 1013 through the third oil pipe 202 along the second oil port 302 of the hydraulic cylinder, and the hydraulic oil is guided to the fourth oil interface 1014 through the main oil channel 1021, and flows back to the oil tank through the fourth oil pipe 203; the oil circuit switching inner core 102 is driven to rotate 90° by the circuit switching motor 106, as shown in FIG. Fig. 9 As shown, the hydraulic oil enters along the first oil interface 1011, and is exported along the third oil interface 1013 through the main oil channel 1021, and the hydraulic oil enters along the second oil port 302 of the hydraulic cylinder 3 through the third oil pipe 202, so that the hydraulic cylinder 3 can achieve rod retraction operation, and the hydraulic oil in the internal oil chamber of the first oil port 301 of the hydraulic cylinder is introduced to the second oil interface 1012 along the first oil port 301 of the hydraulic cylinder through the second oil pipe 201, and the hydraulic oil is guided to the fourth oil interface 1014 through the main oil channel 1021, and flows back to the oil tank through the fourth oil pipe 203;.

[0019] The technical scheme in the above-mentioned embodiment of the present application has at least the following technical effects or advantages: the present invention allows the hydraulic oil to enter along the first oil interface 1011 and be exported along the second oil interface 1012 through the main oil channel 1021, and the hydraulic oil enters along the first oil port 301 of the hydraulic cylinder 3 through the second oil pipe 201, so that the hydraulic cylinder 3 can realize the push rod operation; the oil circuit switching inner core 102 is driven to rotate 90° by the switching motor 106, and the hydraulic oil enters along the first oil interface 1011 and is exported along the third oil interface 1013 through the main oil channel 1021, and the hydraulic oil enters along the second oil port 302 of the hydraulic cylinder 3 through the third oil pipe 202, so that the hydraulic cylinder 3 can realize the retraction operation, and the extension and contraction of the hydraulic cylinder can be controlled by rotating the oil circuit without adding oil circuits and interfaces. Example

[0020] The oil circuit switching core 102 is provided with a one-way flow limiting rotating core 104 at the four ports of the two main oil passages 1021. Figure 4 , Figure 5 and Figure 8 As shown, the one-way flow limiting rotor 104 includes a rotor body 1041, a one-way flow channel 1042 for connecting to the main oil channel 1021 is opened in the middle of the rotor body 1041, a one-way flow limiting inner cavity 1043 is provided in the middle of the one-way flow channel 1042, a top block 1044 is pressed against one end of the inner cavity of the one-way flow limiting inner cavity 1043, and a flow limiting spring 1045 is provided between the top block 1044 and the inner cavity of the one-way flow limiting inner cavity 1043, so that the internal oil circuit of the one-way flow limiting rotor 104 realizes one-way flow, and the one-way flow limiting rotor 104 is provided with a one-way flow limiting spring 1045. Figure 8 and Fig. 9 As shown, during the rod extension and retraction operation of the hydraulic cylinder 3, when the hydraulic oil enters the interior of the hydraulic cylinder 3, the oil is fed in one direction under the action of the one-way flow limiting rotating core 104, thereby avoiding the situation in which the thrust is reduced due to the hydraulic oil backflow and the thrust is unstable, resulting in the push rod retreating; It is worth mentioning that a transmission chamber 105 is provided inside the valve body 101 and on one side of the oil circuit switching inner core 102. An internal gear 1051 is integrally formed on the inner wall of the transmission chamber 105. A planetary gear 1052 is provided on one side of each of the four rotating core bodies 1041. The planetary gears 1052 are in transmission mesh with the internal gear 1051. The rotating core body 1041 is adapted to be connected to the inside of the oil circuit switching inner core 102. During the rotation of the oil circuit switching inner core 102, the rotating core body 1041 can rotate with the rotation of the oil circuit switching inner core 102. The number of teeth of the planetary gear 1052 is the same as that of the internal gear 1051. The gear ratio is 1:8. After the oil circuit switching inner core 102 rotates 90°, the guidance of the oil circuit inside the one-way flow limiting rotor 104 is not changed. In the process of switching the oil circuit, since the rotation speed of the rotor body 1041 is faster than the rotation speed of the oil circuit switching inner core 102, the oil cut-off speed of the channel between the one-way flow channel 1042 in the rotor body 1041 and the main oil channel 1021 is faster than the oil cut-off speed of the channel between the main oil channel 1021 and the first oil interface 1011, the second oil interface 1012, the third oil interface 1013 and the fourth oil interface 1014, further ensuring the stability of the oil pressure during the oil circuit switching process.

[0021] The technical scheme in the above-mentioned embodiment of the present application has at least the following technical effects or advantages: in the rod extension operation of the hydraulic cylinder 3, during the process of the hydraulic oil entering the interior of the hydraulic cylinder 3, the oil is in one direction under the action of the one-way flow limiting core 104, thereby avoiding the situation where the thrust is reduced and the push rod retreats due to the thrust instability caused by the hydraulic oil backflow; at the same time, under the meshing transmission of the inner gear 1051 and the planetary gear 1052 provided on one side of the rotating core body 1041, the rotating core body 1041 can move with the rotation of the planetary gear 1052. It rotates along with the rotation of the oil circuit switching inner core 102. During the oil circuit switching process, since the rotation speed of the rotating core body 1041 is faster than that of the oil circuit switching inner core 102, the oil cut-off speed of the channel between the one-way flow channel 1042 in the rotating core body 1041 and the main oil channel 1021 is faster than the oil cut-off speed of the channel between the main oil channel 1021 and the first oil interface 1011, the second oil interface 1012, the third oil interface 1013 and the fourth oil interface 1014, further ensuring the stability of the oil pressure during the oil circuit switching process. Example

[0022] Combination Figure 4 , Figure 6 and Figure 8 As shown, four groups of pressure relief components 107 are arranged inside the valve body 101. The four groups of pressure relief components 107 are arranged alternately with the first oil interface 1011, the second oil interface 1012, the third oil interface 1013 and the fourth oil interface 1014 of the valve body 101 and are arranged at intervals of 45 degrees. The pressure relief component 107 includes a pressure relief inner cavity 1071 opened inside the valve body 101. The pressure relief inner cavity 1071 is opened at one end close to the oil circuit switching inner core 102. The pressure relief oil hole 1072, the piston 1073 slides in the pressure relief oil hole 1072, the pressure relief assembly 107 is also provided with a pressure plate 1074, and an elastic telescopic rod 1075 is connected between the pressure plate 1074 and the piston 1073, the oil circuit switching inner core 102 has a pressure relief oil channel 1022 that is connected to the two main oil channels 1021, and the other end of the pressure relief oil channel 1022 extends to correspond to the opening position of the pressure relief oil hole 1072. During the oil inlet process, when the oil pressure of the oil circuit is too large, the hydraulic oil enters the pressure relief inner cavity 1071 along the pressure relief oil channel 1022, and the hydraulic oil pushes the piston 1073 to compress the elastic telescopic rod 1075, thereby achieving the oil circuit pressure relief function, maintaining the oil pressure stable and protecting the oil circuit.

[0023] A pressure-adjusting bolt 1076 is threadedly connected along the outside of the valve body 101. The axial direction of the pressure-adjusting bolt 1076 is consistent with the axial direction of the pressure-relief inner cavity 1071, and the inner end of the pressure-adjusting bolt 1076 is in conflict with the pressure plate 1074. By rotating the pressure-adjusting bolt 1076 and adjusting the elastic force of the elastic telescopic rod 1075, the hydraulic oil buffer oil pressure can be adjusted.

[0024] The technical solutions in the above-mentioned embodiments of the present application have at least the following technical effects or advantages: during the oil intake process of the present invention, when the oil pressure in the oil circuit is too large, the hydraulic oil enters the pressure relief cavity 1071 along the pressure relief oil channel 1022, and the hydraulic oil pushes the piston 1073 to compress the elastic telescopic rod 1075, thereby achieving the effect of oil circuit pressure relief, maintaining the oil pressure stable and protecting the oil circuit; the present invention can adjust the hydraulic oil buffer oil pressure by rotating the pressure regulating bolt 1076 to adjust the elastic force of the elastic telescopic rod 1075.

[0025] Of course, the present invention may have many other implementations. Based on this implementation, other implementations obtained by ordinary technicians in this field without any creative work are all within the scope of protection of the present invention.

Claims

1. A hydraulic valve backflow prevention device, comprising a hydraulic valve body (1) and a first oil pipe (2), characterized in that: The hydraulic valve body (1) comprises a valve body (101), an oil circuit switching circular cavity is provided inside the valve body (101), an oil circuit switching inner core (102) is adapted to be connected in the oil circuit switching circular cavity, a first oil interface (1011) is provided at the top of the valve body (101), the first oil interface (1011) is connected to a first oil pipe (2), a second oil interface (1012) is provided on one side of the valve body (101), the second oil interface (1012) is connected to a second oil pipe (201), and the other end of the second oil pipe (201) is connected to a first oil port (301) of a hydraulic cylinder (3), a third oil interface (1013) is provided on the other side of the valve body (101), the third oil interface (1013) is connected to a third oil pipe (202), and the other end of the third oil pipe (202) is connected to a first oil port (301) of the hydraulic cylinder (3), The valve body (101) is connected to a second oil port (302) of the hydraulic cylinder, a fourth oil interface (1014) is provided at the bottom of the valve body (101), the fourth oil interface (1014) is connected to a fourth oil pipe (203), two main oil passages (1021) in an "L" shape are provided inside the oil passage switching inner core (102), a side valve cover (103) is provided on one side of the valve body (101), a switching motor (106) is provided on the outer wall of the side valve cover (103), a spline shaft portion (1061) is provided at the output shaft end of the switching motor (106), a spline shaft hole (1053) matched with the spline shaft portion (1061) for transmission connection is provided on one side of the valve body (101), and a one-way flow limiting rotating core (104) is provided at four port positions of the oil passage switching inner core (102) and located in the two main oil passages (1021).

2. A hydraulic valve backflow prevention device according to claim 1, characterized in that: The first oil interface (1011), the second oil interface (1012), the third oil interface (1013) and the fourth oil interface (1014) are arranged in a circular array at intervals of 90 degrees, and the four ports of the two main oil passages (1021) in the oil passage switching inner core (102) are arranged in a circular array at intervals of 90 degrees.

3. A hydraulic valve backflow prevention device according to claim 1, characterized in that: The one-way flow limiting rotor (104) comprises a rotor body (1041), a one-way flow channel (1042) for connecting with the main oil channel (1021) is provided in the middle of the rotor body (1041), a one-way flow limiting inner cavity (1043) is provided in the middle of the one-way flow channel (1042), a top block (1044) is provided at one end of the inner cavity of the one-way flow limiting inner cavity (1043) for top pressure, and a flow limiting spring (1045) is provided between the top block (1044) and the inner cavity of the one-way flow limiting inner cavity (1043).

4. A hydraulic valve backflow prevention device according to claim 1 or 3, characterized in that: A transmission chamber (105) is provided inside the valve body (101) and on one side of the oil circuit switching inner core (102); an internal gear (1051) is integrally formed on the inner wall of the transmission chamber (105); planetary gears (1052) are provided on one side of each of the four rotating core bodies (1041), and the planetary gears (1052) are in transmission meshing engagement with the internal gear (1051).

5. A hydraulic valve backflow prevention device according to claim 4, characterized in that: The rotating core body (1041) is coupled and connected to the inside of the oil circuit switching inner core (102), and the ratio of the number of teeth of the planetary gear (1052) to the number of teeth of the internal gear (1051) is 1:

8.

6. A hydraulic valve backflow prevention device according to claim 1, characterized in that: Four groups of pressure relief components (107) are arranged inside the valve body (101), and the four groups of pressure relief components (107) and the first oil interface (1011), the second oil interface (1012), the third oil interface (1013) and the fourth oil interface (1014) of the valve body (101) are arranged alternately and at intervals of 45 degrees.

7. A hydraulic valve backflow prevention device according to claim 1, characterized in that: The pressure relief component (107) comprises a pressure relief inner cavity (1071) opened inside the valve body (101), a pressure relief oil hole (1072) is opened at one end of the pressure relief inner cavity (1071) close to the oil circuit switching inner core (102), a piston (1073) is slidably arranged inside the pressure relief oil hole (1072), a pressure plate (1074) is further arranged inside the pressure relief component (107), and an elastic telescopic rod (1075) is connected between the pressure plate (1074) and the piston (1073), a pressure relief oil passage (1022) is connected to the two main oil passages (1021) inside the oil circuit switching inner core (102), and the other end of the pressure relief oil passage (1022) extends to correspond to the opening position of the pressure relief oil hole (1072).

8. A hydraulic valve backflow prevention device according to claim 7, characterized in that: A pressure regulating bolt (1076) is threadedly connected along the outside of the valve body (101), the axial direction of the pressure regulating bolt (1076) is consistent with the axial direction of the pressure-relief inner cavity (1071), and the inner end of the pressure regulating bolt (1076) is in conflict with the pressure plate (1074).

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