Unloading proportional relief valve

Abstract

This invention relates to the field of hydraulic system pressure control technology. The invention discloses an unloading proportional relief valve, comprising a valve body, with a first cover plate and a second cover plate sequentially connected to one end of the valve body; a safety valve is integrated on the first cover plate, and a pressure sensor, an electromagnetic relief valve, and an amplifier are integrated on the valve body; a bushing is connected to the lower end face of the second cover plate, and a spring cavity C is provided inside the second cover plate; a valve sleeve is inserted into the bushing, and the valve sleeve fits against the inner end face of the bushing; a valve core is slidably disposed within the valve sleeve, and a spring is disposed in the inner hole of the valve core, with one end of the spring extending into the spring cavity C. This invention has the advantages of small size, compact structure, low power loss, fast action, and high integration, and is particularly suitable for the control and regulation of high-flow hydraulic systems.

Description

Technical Field

[0001] This invention relates to the field of hydraulic system pressure control technology, and in particular to a novel integrated safety valve, electromagnetic relief valve, and pressure sensor-based unloading proportional relief valve. Background Technology

[0002] Pressure control components are used to regulate or limit the pressure of hydraulic systems. Among them, relief valves use relief action to regulate oil circuit pressure, while unloading valves are a special type of relief valve. The function of unloading valves is to reduce the system pressure to a minimum when the hydraulic system does not need to transmit power, so as to save power consumption.

[0003] The hydraulic systems of heavy equipment such as forging and pressing machinery and metallurgical machinery are characterized by high pressure and instantaneous ultra-large flow. Their hydraulic pump stations usually adopt the form of multiple hydraulic pumps and multiple accumulators. When these heavy equipment are shut down, the hydraulic system often needs to be unloaded. If conventional unloading methods such as electromagnetic relief valves, electro-hydraulic directional valves, and cartridge valves are used to unload the hydraulic system, the huge high-pressure liquid energy accumulated in the high-pressure pipelines and high-pressure accumulators will be released instantaneously, which will generate impact vibration and noise. The bursting of air bubbles in the oil will exacerbate this effect, which may cause loosening of connecting bolts, rupture of hydraulic components and pipes, or even serious oil leakage of equipment, thus having a significant impact on the stable operation, reliability and service life of the entire heavy equipment.

[0004] For example, Chinese Patent No. CN119412394A discloses a method and system for proportional pressure relief and unloading of a high-pressure ultra-high flow hydraulic system. Although this patent solves the above problems, it has the following drawbacks: complex system piping, dispersed component arrangement, and the switching of control valve 11 can only control the on / off of cartridge valve 8, and cannot achieve multi-stage pressure control.

[0005] Secondly, in multi-stage pressure control hydraulic systems, traditional technology typically connects the remote control port of the remote unloading valve to the inlet ports of three remote pressure regulating valves (direct-acting relief valves) with different pressures via a three-position four-way solenoid directional valve. When the solenoid directional valve switches to the left, center, or right position, the pressure controlled by the remote unloading valve is the pressure set by the three remote pressure regulating valves, thus achieving multi-stage pressure control at high and low pressures.

[0006] For example, the digital logic multi-level remote pressure regulating circuit disclosed in Chinese patent CN210799555U can regulate pressure remotely in multiple levels, but the set pressure is stepped and not linearly proportional, and there are too many remote pressure regulating valves, which is too costly. Summary of the Invention

[0007] The purpose of this invention is to provide an unloading proportional relief valve that can reduce impact vibration, reduce noise, improve system stability and reliability, extend system service life, simplify oil pipe layout, optimize component layout, meet proportional pressure control requirements, reduce costs, and improve product market competitiveness.

[0008] To solve the above-mentioned technical problems, the present invention provides an unloading proportional relief valve, including a valve body, one end of which is sequentially connected to a first cover plate and a second cover plate; a safety valve is integrated on the first cover plate, and a pressure sensor, an electromagnetic relief valve, and an amplifier are integrated on the valve body; a bushing is connected to the lower end face of the second cover plate, and a spring cavity C is provided inside the second cover plate; a valve sleeve is inserted into the bushing, and the valve sleeve fits against the inner end face of the bushing; a valve core is slidably disposed inside the valve sleeve, and a spring is disposed in the inner hole of the valve core, with one end of the spring extending into the spring cavity C; the electromagnetic relief valve includes an electromagnetic valve sleeve, on which a pressure cavity P is provided; The second cover plate is provided with a control oil port X and a control oil passage Y, and control oil passages X1 and Y2 are respectively provided on both sides of the spring cavity C; the first cover plate is provided with control oil passages X2, X3, X4, X5, Y1 and return oil passage T2; the valve body is provided with control oil passage X6 and return oil passage T1; The control oil port X is connected to the control oil circuit X1. The control oil circuit X1 is connected to the control oil circuits X2 and X3. The control oil circuit X3 is connected to the spring cavity C. The control oil circuit X2 is connected to the control oil circuits X4 and X5. The control oil circuit X5 is connected to the control oil circuit X6 and the pressure cavity P. The pressure cavity P is connected to the return oil circuit T1, the return oil circuit T2, the control oil circuit Y1, and the control oil circuit Y2. The control oil circuit Y2 is connected to the control oil circuit Y.

[0009] It also includes a valve block, which is used to install the valve body, first cover plate, second cover plate, bushing, valve sleeve, valve core, and spring as a whole. The valve block is provided with an oil inlet A and an oil outlet B.

[0010] The first cover plate is provided with a first damping screw plug and a second damping screw plug. A first damping hole z1 is opened on the first damping screw plug, and a second damping hole z2 is opened on the second damping screw plug. The first damping hole z1 is used to connect the control oil circuit X3 and the spring cavity C, and the second damping hole z2 is used to connect the control oil circuit X1, the control oil circuit X2 and the control oil circuit X3.

[0011] The electromagnetic relief valve includes an electromagnetic valve seat, which is installed inside the valve body; an electromagnetic valve sleeve is fitted over the electromagnetic valve seat, and a conical valve core is slidably disposed inside the electromagnetic valve sleeve; one end of the electromagnetic valve sleeve is connected to an electromagnet, which works in cooperation with the conical valve core through a push rod; one end of the conical valve core is provided with a conical surface k that cooperates and seals with the pointed edge K of the electromagnetic valve seat, and the other end is in contact with the push rod of the electromagnet.

[0012] The solenoid valve seat is provided with an oil inlet hole I, and the cylindrical surface of the conical valve core is provided with a spiral groove J. The solenoid valve sleeve is threadedly connected to the valve body.

[0013] The safety valve includes a safety valve seat, which is installed inside a first cover plate. A ball valve core is slidably disposed inside the safety valve seat, and a safety valve sleeve is fitted over the safety valve seat. One end of the ball valve core is provided with a conical surface n that cooperates and seals with the pointed edge N of the safety valve seat, as well as a damping groove z, and the other end is a ball head surface Q. An adjusting screw is internally threaded into the safety valve sleeve, and a safety spring is disposed inside the adjusting screw. One end of the safety spring contacts the ball head surface Q through the conical surface of the safety spring seat, and the other end is connected to the adjusting screw through an adjusting shim.

[0014] The safety valve seat is provided with an oblique hole O. The safety valve sleeve is threadedly connected to the first cover plate. The adjusting screw is locked to the safety valve sleeve through the open retaining ring and the locking nut (1610).

[0015] The cylindrical surface of the valve core is provided with a pressure equalization groove and a sealing ring groove. The sealing ring groove is used to isolate the oil discharge port B from the spring cavity C.

[0016] The valve body, the first cover plate, and the second cover plate are positioned by cylindrical pins.

[0017] The first cover plate is also provided with a hexagonal screw plug and an internal hexagonal tapered screw plug for sealing excess oil ports. The valve body is provided with a threaded hole for connecting the pressure test connector. The threaded hole is sealed by the sealing screw plug when not in the pressure test state.

[0018] Compared with existing technologies, this invention has advantages such as small size, compact structure, low power loss, fast action, and high integration. It is particularly suitable for the control and regulation of large-flow hydraulic systems. It has low flow damping and large flow capacity, making it particularly suitable for high-flow applications. Due to its cone valve structure, internal leakage is very small and there is no jamming. It has a fast action speed because it relies on the cone surface to seal and cut off the oil circuit. The oil circuit is immediately connected as soon as the valve core is slightly lifted. In addition, the valve core has a small stroke and sensitive action, making it particularly suitable for high-speed opening applications. It has strong anti-pollution ability and reliable operation.

[0019] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, and in order to make the above and other objects, features and advantages of the present invention more apparent and understandable, specific embodiments of the present invention are described below. Attached Figure Description

[0020] One or more embodiments are illustrated by way of example with reference numerals in the accompanying drawings. These illustrations do not constitute a limitation on the embodiments. Elements with the same reference numerals in the drawings are denoted as similar elements. Unless otherwise stated, the figures in the drawings are not to be limited by scale.

[0021] Figure 1 This is a schematic diagram of the longitudinal structure of the present invention; Figure 2 yes Figure 1 A schematic diagram of the longitudinal structure of the electromagnetic overflow valve; Figure 3 yes Figure 2 A schematic diagram of the longitudinal section structure of the solenoid valve seat; Figure 4 yes Figure 2 Schematic diagram of the longitudinal section structure of the conical valve core; Figure 5 yes Figure 1 A schematic diagram of the longitudinal section structure of a safety valve; Figure 6 yes Figure 5 Schematic diagram of the longitudinal section structure of the safety valve seat; Figure 7 yes Figure 5 Schematic diagram of the longitudinal section structure of the ball head valve core; Figure 8 yes Figure 1 A schematic diagram of the longitudinal section structure of the first damping screw plug; Figure 9 yes Figure 1 A schematic diagram of the longitudinal section structure of the second damping screw plug; Figure 10 This is a schematic diagram of the present invention.

[0022] In the diagram: 1-Sleeve ring, 2-Valve sleeve, 3-Valve core, 4-Spring, 5-Second cover plate, 6-First damping plug, 7-First cover plate, 8-Second damping plug, 9-Hexagonal plug, 10-Internal hexagonal tapered plug, 11-Sealing plug, 12-Valve body, 13-Pressure sensor, 14-Solenoid relief valve, 141-Solenoid valve seat, 142-Solenoid valve sleeve, 143-Conical valve core, 144-Solenoid, 145-Push rod, 15-Amplifier, 16-Safety valve, 161-Safety valve seat, 162-Ball valve core, 163-Safety spring seat, 164-Safety spring, 165-Safety valve sleeve, 166-Adjusting screw, 167-Adjusting shim, 168-Shim, 169-Open retaining ring, 1610-Locking nut. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of this invention clearer, the embodiments of this invention will be described in detail below with reference to the accompanying drawings. However, those skilled in the art will understand that many technical details are presented in the embodiments of this invention to facilitate a better understanding of this application. However, the technical solutions claimed in this application can be implemented even without these technical details and various variations and modifications based on the following embodiments. The division of the following embodiments is for ease of description and should not constitute any limitation on the specific implementation of this invention. The embodiments can be combined with and referenced by each other without contradiction.

[0024] Example 1 A is the oil inlet, B is the oil outlet, C is the spring chamber, X is the control oil inlet, Y is the return oil inlet, X1, X2, X3, X4, X5, and X6 are control oil circuits, P is the pressure chamber, T is the oblique hole, T1 and T2 are return oil circuits, and Y1 and Y2 are control oil circuits. F is the large outer cylindrical surface of valve seat 141, G is the small outer cylindrical surface of valve seat 141, H is the threaded hole of valve seat 141, I is the small oil inlet hole of valve seat 141, K is the pointed edge of the small oil inlet hole I of valve seat 141, k is the conical surface of conical valve core 143, J is the spiral groove on the outer cylindrical surface of conical valve core 143, and L is the outer cylindrical surface of conical valve core 143.

[0025] W1 is the large outer cylindrical surface of valve seat 161, W2 is the small outer cylindrical surface of valve seat 161, M is the inner cylindrical surface of valve seat 161, O is the oblique hole of valve seat 161, N is the pointed edge of the inner cylindrical surface, m is the outer cylindrical surface of ball valve core 162, n is the conical surface of ball valve core 162, Q is the ball surface of ball valve core 162, z is the damping groove of ball valve core 162, and P1 is the pressure chamber of the safety valve.

[0026] like Figures 1-9 As shown, the safety valve 16 is integrated on the first cover plate 7, and the electromagnetic relief valve 14, pressure sensor 13, and amplifier 15 are integrated on the valve body 12. The valve body 12 is also connected to the first cover plate 7. The bushing 1, valve sleeve 2, valve core 3, and spring 4 are integrated on the lower end face of the second cover plate 5. The valve body 12 and the two cover plates (first cover plate 7 and second cover plate 5) are connected from top to bottom and assembled on the valve block together with the bushing 1, valve sleeve 2, valve core 3, and spring 4. The oil circuit is designed to connect the lower end of the valve core 3 to the inlet of the safety valve 16, the detection end of the pressure sensor 13, and the inlet of the electromagnetic relief valve 14. The oil circuit is also designed to connect the oil discharge port of the valve sleeve 2 to the oil return port of the safety valve 16 and the oil return port of the electromagnetic relief valve 14.

[0027] Specifically, the bushing 1 mates with the cylindrical surface of the valve sleeve 2, with the major diameter centered, and the upper end face of the valve sleeve 2 fits against the inner end face of the bushing 1; the valve core 3 mates with the cylindrical surface of the valve sleeve 2, with the major diameter centered, and there is a gap between the two; the lower end face of the valve core 3 and the pointed edge of the cylindrical surface mate with the conical surface of the valve sleeve 2, and the conical surface seals; the valve core 3 moves up and down inside the valve sleeve 2; the cylindrical surface of the valve core 3 is provided with a pressure equalizing groove to prevent the valve core from jamming when moving up and down; the cylindrical surface of the valve core 3 is also provided with a sealing ring groove to prevent the oil discharge port B from communicating with the spring cavity C; the spring 4 is assembled in the inner hole of the valve core 3 and is positioned by the inner hole of the valve core 3; the bushing 1, valve sleeve 2, and valve core 3 are inserted together into the valve block (not shown in the figure).

[0028] Furthermore, the upper end face of the bushing 1 is fitted with the lower end face of the second cover plate 5. The second cover plate 5 is provided with a spring cavity C, which is an inner hole. The inner hole of the bushing 1 is coaxial with the spring cavity C. The upper end of the spring 4 is assembled in the spring cavity C of the second cover plate 5 and is positioned by the spring cavity C. The left end of the second cover plate 5 is provided with a control oil port X and a control oil passage X1. The right end of the second cover plate 5 is provided with a return oil port Y and a return oil passage Y2. The upper end face of the second cover plate 5 is fitted with the lower end face of the first cover plate 7 and is positioned by a cylindrical pin (not shown in the figure).

[0029] Furthermore, the lower end face of the first cover plate 7 has a threaded hole at its center for assembling the first damping plug 6 and the second damping plug 8. The upper end of the first damping plug 6 has a first damping hole z1 with a diameter of 0.8 mm, and the lower end of the first damping plug 6 has an internal hexagonal hole. The upper end of the second damping plug 8 has a second damping hole z2 with a diameter of 1 mm, and the lower end of the second damping plug 8 has an internal hexagonal hole. The first cover plate 7 has control oil passages X2, X3, X4, and X5, and also has return oil passages Y1 and T2. Control oil passages X2, X3, X4, and X5 are interconnected, and return oil passage T2 is connected to return oil passage Y1. A hexagonal plug 9 and an internal hexagonal tapered plug 10 are assembled on the left end of the first cover plate 7 to seal the control oil passages. A safety valve 16 is also assembled on the upper right end of the first cover plate 7.

[0030] Specifically, the upper end face of the first cover plate 7 is fitted with the lower end face of the valve body 12. The valve body 12 is provided with a control oil circuit X6 and a pressure chamber P, and the pressure chamber P is connected to the control oil circuit X6. The left end of the valve body 12 is provided with a threaded hole for pressure measurement. When pressure measurement is not required, it is sealed with a sealing plug 11. An electromagnetic relief valve 14 is assembled on the right end of the valve body 12. The large outer cylindrical surface F of the electromagnetic valve seat 141 mates with the inner cylindrical surface of the valve body 12 for large diameter centering. The left end face of the electromagnetic valve seat 141 is fitted with the bottom surface of the inner hole of the valve body 12 to axially position the electromagnetic valve seat 141 and prevent the electromagnetic valve seat 141 from moving left and right. The electromagnetic valve seat 141 is provided with a threaded hole H and an oil inlet hole I, and the threaded hole H is connected to the oil inlet hole I. The small outer cylindrical surface of the solenoid valve seat 141 mates with the inner hole of the solenoid valve sleeve 142, providing major diameter centering. The solenoid valve sleeve 142 is threadedly connected to the valve body 12 and has an oblique hole T. The inner hole of the solenoid valve sleeve 142 mates with the outer cylindrical surface L of the conical valve core 143, providing major diameter centering. The outer cylindrical surface L of the conical valve core 143 has a spiral groove J, and the left end of the conical valve core 143 has a conical surface k. The conical surface k seals with the pointed edge K of the oil inlet hole I of the solenoid valve seat 141, preventing the pressure chamber P from communicating with the oblique hole T. The right end of the conical valve core 143 is in contact with the push rod 145 of the electromagnet 144.

[0031] Furthermore, the upper end face of the valve body 12 is fitted with the amplifier 15, and a pressure sensor 13 is assembled between the amplifier 15 and the valve body 12. The pressure sensor 13 detects the pressure in the pressure chamber P. The valve body 12 is provided with a return oil passage T1, which is connected to the inclined hole T and the return oil passage T2 respectively. The return oil passage T2 is connected to the return end of the safety valve 16.

[0032] Specifically, the large outer cylindrical surface W1 of the safety valve seat 161 of the safety valve 16 mates with the inner cylindrical surface of the first cover plate 7, providing large-diameter centering; there is a large gap between the small outer cylindrical surface W2 of the safety valve seat 161 and the inner hole of the first cover plate 7; a stepped end face is provided between the small outer cylindrical surface W2 and the large outer cylindrical surface W1 of the safety valve seat 161, which fits against the bottom surface of the inner hole of the valve body 12, for axial positioning of the safety valve seat 161, preventing lateral axial movement of the safety valve seat 161. The inner cylindrical surface M of the safety valve seat 161 mates with the outer cylindrical surface m of the ball valve core 162, providing large-diameter centering; the conical surface n of the ball valve core 162 seals with the pointed edge N conical surface of the safety valve seat 161; the ball head surface Q of the ball valve core 162 mates with the conical surface of the safety spring seat 163, and the safety spring seat 163 can automatically center due to the action of the ball head surface Q of the ball valve core 162. A safety spring 164 is connected to the right end of the safety spring seat 163. An adjusting shim 167 is connected to the right end of the safety spring 164. A shim 168 is connected to the right end of the adjusting shim 167. The safety spring 164, adjusting shim 167, and shim 168 are assembled together in the inner hole of the adjusting screw 166, with the right end of shim 168 fitting against the bottom surface of the inner hole of the adjusting screw 166. The adjusting screw 166 is threadedly connected to the safety valve sleeve 165 and the locking nut 1610. An open retaining ring 169 is assembled between the adjusting screw 166 and the locking nut 1610. The safety valve sleeve 165 is threadedly connected to the first cover plate 7. The safety valve sleeve 165, together with the adjusting screw 166 and the safety spring seat 163, positions the spring.

[0033] Example 2 Working principle of electromagnetic relief valve: When there is no current in the electromagnet 144, the pressure oil at the left end of the solenoid valve seat 141 pushes the conical valve core 143 to the right through the threaded hole H and the small oil inlet I of the solenoid valve seat 141. The conical surface k of the conical valve core 143 disengages from the sharp edge K of the solenoid valve seat 141, and the small oil inlet I of the solenoid valve seat 141 connects with the oblique hole T on the solenoid valve sleeve 142. The pressure oil overflows through the oblique hole T, and the solenoid relief valve 14 opens. When the electromagnet 144 is energized, it generates a suction force, pushing the push rod 145 to the left. The push rod pushes the conical valve core 143 to the left, so that the conical surface k of the conical valve core 143 is in contact with the sharp edge K of the solenoid valve seat 141. The small oil inlet I of the solenoid valve seat 141 is no longer connected with the oblique hole T on the solenoid valve sleeve 142, and the solenoid relief valve 14 closes.

[0034] When the product of the pressure at the left end of the solenoid valve seat 141 and the area of ​​the oil inlet hole I of the solenoid valve seat 141 is greater than the attraction force of the electromagnet 144, the conical valve core 143 moves to the right, and the conical surface k of the conical valve core 143 disengages from the sharp edge K of the valve seat 141. The oil inlet hole I of the solenoid valve seat 141 connects with the oblique hole T on the solenoid valve sleeve 142, and the pressurized oil overflows through the oblique hole T, and the solenoid relief valve 14 opens again. When the current increases, the product of the pressure at the left end of the solenoid valve seat 141 and the area of ​​the oil inlet hole I of the solenoid valve seat 141 is less than the attraction force of the electromagnet 144. Under the action of the push rod 145, the conical valve core 143 is pressed against the solenoid valve seat 141 again, and the conical surface k of the conical valve core 143 is in contact with the sharp edge K of the solenoid valve seat 141, and the solenoid relief valve 14 closes.

[0035] Thus, different pressures correspond to different electromagnet attraction forces, which in turn correspond to different currents. The pressure and current change in a proportional relationship, and the opening pressure of the electromagnetic relief valve 14 changes proportionally to the current. This proportional change is a dynamic process. During this dynamic process, because the spiral groove on the conical valve core 143 connects the inclined hole T and the push rod cavity, the conical valve core 143 moves quickly and without jamming.

[0036] Example 3 Safety valve working principle: The pressure oil at the left end of safety valve 16 enters the pressure chamber P1 of the safety valve through the evenly distributed oblique holes O around the circumference of safety valve seat 161 and then through the damping groove z of the ball valve core. This pushes the ball valve core 162 to the right. When the product of the pressure and the area of ​​the left end of the ball valve core 162 is greater than the preload of the safety spring 164, the conical surface n of the ball valve core 162 disengages from the pointed edge N of the valve seat 161, and the pressure oil enters the return oil circuit Y1 for overflow, thus opening the safety valve. Conversely, when the product of the pressure and the area of ​​the left end of the ball valve core 162 is less than the preload of the safety spring 164, the ball valve core 162 is pressed against the safety valve seat 161 under the action of the safety spring 164. The conical surface n of the ball valve core 162 and the pointed edge N of the safety valve seat 161 fit together to form a conical seal, preventing the pressure oil at the left end of safety valve 16 from entering the return oil circuit Y1, and the installation valve 16 remains closed. The opening pressure of the safety valve can be adjusted by moving the adjusting screw 166 left and right and by adjusting the number of shims 167. After the opening pressure of the safety valve 16 is set, it is locked by locking nut 1610.

[0037] Example 4 like Figure 10 As shown, the working principle of this invention is as follows: The pressurized oil output from the pump enters the inlet A, passes through the valve block (not shown in the diagram) to the control port X, and then enters the control oil circuit X1. It then passes through the second damping hole z2 of the second damping plug 8 to enter control oil circuits X2 and X3. The pressurized oil in control oil circuit X3 is divided into two paths: one path passes through the first damping hole z1 of the first damping plug 6 to the spring chamber C, and the other path goes to the left end of the safety valve 16. When the pressure reaches the opening pressure of the safety valve 16, the safety valve 16 opens, and the pressurized oil enters the return oil circuit Y1, then the return oil circuit Y2, and overflows at the return port Y. The safety valve 16 protects the system. Conversely, when the pressure does not reach the opening pressure of the safety valve 16, the installation valve 16 remains closed.

[0038] The pressurized oil entering control oil circuit X2 passes through control oil circuits X4, X5, and X6 into pressure chamber P. Pressure sensor 13 detects the pressure in pressure chamber P and sends a signal to the amplifier, which in turn sends a signal to the electromagnet, causing the electromagnet to generate a pulling force. When the pressure in pressure chamber P reaches the opening pressure of electromagnetic relief valve 14, electromagnetic relief valve 14 opens, and the pressurized oil in pressure chamber P passes through oblique hole T and successively enters return oil circuit T1 and return oil circuit T2, then successively enters return oil circuit Y1 and return oil circuit Y2, reaching return oil port Y for overflow. At this time, spring chamber C is connected to return oil port Y, and the product of the pressure at inlet A and the cylindrical surface area of ​​valve core 3 is greater than the preload of spring 4. Valve core 3 moves upward, and the cylindrical tip of valve core 3 disengages from the conical surface of valve sleeve 2. Inlet A is connected to outlet B, and pressurized oil enters outlet B from inlet A, thus unloading the system. When the current increases, according to the working principle of the electromagnetic relief valve 14, the electromagnetic relief valve 14 closes, the spring chamber C is not connected to the return port Y, and the pressure in the spring chamber C is the same as the pressure in the inlet port A. Under the action of the pressure in the spring chamber C and the preload of the spring 4, the valve core 3 is pressed against the conical surface of the valve sleeve 2, and the inlet port A is not connected to the outlet port B, so the system is not unloaded. In this way, the unloading pressure of the system is proportional to the opening pressure of the electromagnetic relief valve, and also proportional to the current of the electromagnet. When the system pressure is abnormal, the safety valve opens, the spring chamber C is connected to the return port Y, and similarly, the inlet port A is connected to the outlet port B, so the system is unloaded.

[0039] In summary, integrating the safety valve, solenoid relief valve, and pressure sensor into the unloading relief valve offers high integration, simplifies system piping, optimizes component placement, and also provides the following benefits. 1) The safety valve, electromagnetic relief valve, and pressure sensor are integrated into the unloading relief valve, which has a high degree of integration, simplifies the system piping, and optimizes the component layout.

[0040] 2) The safety valve, electromagnetic relief valve, and pressure sensor are integrated into the unloading relief valve, which has a high degree of integration, saves installation space of the main unit, and reduces the cost of the main unit.

[0041] 3) The safety valve, solenoid relief valve, and pressure sensor are integrated into the unloading relief valve. Since the unloading pressure is proportional to the opening pressure of the solenoid relief valve, and further proportional to the current, the requirements of multi-stage pressure control are met, the number of remote pressure regulating valves is reduced, and the cost is greatly reduced.

[0042] 4) Integrating the safety valve, solenoid relief valve, and pressure sensor into the unloading relief valve reduces pressure loss and energy consumption.

[0043] 5) The safety valve, electromagnetic relief valve, and pressure sensor are integrated into the unloading relief valve. Due to the rapid response of the electromagnetic relief valve, impact vibration and noise are reduced.

[0044] 6) Integrating the safety valve, solenoid relief valve, and pressure sensor into the unloading relief valve improves the system's stability, reliability, and service life due to the rapid response of the solenoid relief valve and the protective function of the safety valve, thereby enhancing the product's market competitiveness.

[0045] Those skilled in the art will understand that the above embodiments can be modified in form and detail in practical applications without departing from the spirit and scope of the invention.

Claims

1. An unloading proportional relief valve characterized by: The system includes a valve body (12), one end of which is connected to a first cover plate (7) and a second cover plate (5) in sequence; a safety valve (16) is integrated on the first cover plate (7), and a pressure sensor (13), an electromagnetic overflow valve (14), and an amplifier (15) are integrated on the valve body (12); a bushing (1) is connected to the lower end face of the second cover plate (5), and a spring cavity C is provided inside the second cover plate (5); a valve sleeve (2) is inserted into the bushing (1), and the valve sleeve (2) is in contact with the inner end face of the bushing (1); a valve core (3) is slidably arranged inside the valve sleeve (2), and a spring (4) is provided in the inner hole of the valve core (3), with one end of the spring (4) extending into the spring cavity C; the electromagnetic overflow valve (14) includes an electromagnetic valve sleeve (142), and a pressure cavity P is provided on the electromagnetic valve sleeve (142); The second cover plate (5) is provided with a control oil port X and a control oil passage Y, and control oil passage X1 and control oil passage Y2 are respectively provided on both sides of the spring cavity C; the first cover plate (7) is provided with control oil passage X2, control oil passage X3, control oil passage X4, control oil passage X5, control oil passage Y1 and return oil passage T2; the valve body (12) is provided with control oil passage X6 and return oil passage T1; The control oil port X is connected to the control oil circuit X1. The control oil circuit X1 is connected to the control oil circuits X2 and X3. The control oil circuit X3 is connected to the spring cavity C. The control oil circuit X2 is connected to the control oil circuits X4 and X5. The control oil circuit X5 is connected to the control oil circuit X6 and the pressure cavity P. The pressure cavity P is connected to the return oil circuit T1, the return oil circuit T2, the control oil circuit Y1, and the control oil circuit Y2. The control oil circuit Y2 is connected to the control oil circuit Y.

2. The unloading proportional relief valve of claim 1, wherein: It also includes a valve block for integrally mounting the valve body (12), the first cover plate (7), the second cover plate (5), the bushing (1), the valve sleeve (2), the valve core (3), and the spring (4). The valve block is provided with an oil inlet A and an oil outlet B.

3. The unloading proportional relief valve of claim 1, wherein: The first cover plate (7) is provided with a first damping screw plug (6) and a second damping screw plug (8). A first damping hole z1 is provided on the first damping screw plug (6), and a second damping hole z2 is provided on the second damping screw plug (8). The first damping hole z1 is used to connect the control oil circuit X3 and the spring cavity C, and the second damping hole z2 is used to connect the control oil circuit X1, the control oil circuit X2 and the control oil circuit X3.

4. The unloading proportional relief valve of claim 1, wherein: The electromagnetic overflow valve (14) includes an electromagnetic valve seat (141), which is installed inside the valve body (12); the electromagnetic valve sleeve (142) is sleeved outside the electromagnetic valve seat (141), and a conical valve core (143) is slidably arranged inside the electromagnetic valve sleeve (142); one end of the electromagnetic valve sleeve (142) is connected to an electromagnet (144), which works in cooperation with the conical valve core (143) through a push rod (145); one end of the conical valve core (143) is provided with a conical surface k that cooperates and seals with the pointed edge K of the electromagnetic valve seat (141), and the other end is in contact with the push rod (145) of the electromagnet (144).

5. The unloading proportional relief valve of claim 4, wherein: The solenoid valve seat (141) is provided with an oil inlet hole I, the cylindrical surface of the conical valve core (143) is provided with a spiral groove J, and the solenoid valve sleeve (142) is threadedly connected to the valve body (12).

6. The unloading proportional relief valve as described in claim 1, characterized in that: The safety valve (16) includes a safety valve seat (161), which is installed inside the first cover plate (7). A ball valve core (162) is slidably disposed inside the safety valve seat (161), and a safety valve sleeve (165) is fitted over the safety valve seat (161). One end of the ball valve core (162) is provided with a conical surface n that cooperates with and seals the sharp edge N of the safety valve seat (161) and a damping groove z, and the other end is a ball head surface Q. An adjusting screw (166) is threadedly connected inside the safety valve sleeve (165), and a safety spring (164) is provided inside the adjusting screw (166). One end of the safety spring (164) contacts the ball head surface Q through the conical surface of the safety spring seat (163), and the other end is connected to the adjusting screw (166) through adjusting shims (167) and shims (168).

7. The unloading proportional relief valve as described in claim 6, characterized in that: The safety valve seat (161) is provided with an oblique hole O. The safety valve sleeve (165) is threadedly connected to the first cover plate (7). The adjusting screw (166) is locked to the safety valve sleeve (165) through the open retaining ring (169) and the locking nut (1610).

8. The unloading proportional relief valve as described in claim 2, characterized in that: The cylindrical surface of the valve core (3) is provided with a pressure equalization groove and a sealing ring groove. The sealing ring groove is used to isolate the oil discharge port B from the spring cavity C.

9. The unloading proportional relief valve as described in claim 1, characterized in that: The valve body (12), the first cover plate (7), and the second cover plate (5) are positioned by cylindrical pins.

10. The unloading proportional relief valve as described in claim 1, characterized in that: The first cover plate (7) is also provided with a hexagonal screw plug (9) and an internal hexagonal tapered screw plug (10) for sealing excess oil ports. The valve body (12) is provided with a threaded hole for connecting the pressure test connector. The threaded hole is sealed by the sealing screw plug (11) in the non-pressure test state.

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