Unloading proportional overflow valve

Abstract

The invention relates to the technical field of hydraulic system pressure control. The unloading proportional overflow valve comprises a valve body, and one end of the valve body is sequentially connected with a first cover plate and a second cover plate; a safety valve is integrated on the first cover plate; a pressure sensor, an electromagnetic relief valve and an amplifier are integrated on the valve body; the lower end face of the second cover plate is connected with a bushing ring, and a spring cavity C is formed in the second cover plate; a valve sleeve is inserted into the bushing ring, and the valve sleeve is attached to the inner end face of the bushing ring; a valve element is arranged in the valve sleeve in a sliding mode, a spring is arranged in an inner hole of the valve element, and one end of the spring extends into the spring cavity C. The invention has the advantages of small volume, compact structure, small power loss, fast action, high integration level and the like, and is particularly suitable for control and regulation of a high-flow hydraulic system.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of hydraulic system pressure control, in particular to a new type of unloading proportional relief valve integrated with a safety valve, an electromagnetic relief valve and a pressure sensor. BACKGROUND

[0002] The pressure control element is used to adjust or limit the pressure of the hydraulic system, among which the relief valve is used to adjust the pressure of the oil circuit by overflow, and the unloading valve is a special relief valve. The function of the unloading valve is to reduce the system pressure to the minimum when the hydraulic system does not need to deliver power, so as to save power consumption.

[0003] The hydraulic system of heavy equipment such as forging and pressing machinery and metallurgical machinery has the characteristics of high pressure and instantaneous super large flow. The hydraulic pump station usually adopts the form of multiple hydraulic pumps + multiple accumulators. When these heavy equipment are shut down, the hydraulic system often needs to be unloaded. If the conventional unloading methods such as electromagnetic relief valve, electro-hydraulic directional valve and cartridge valve are used to unload the hydraulic system, the huge high-pressure liquid energy accumulated in the high-pressure pipeline and high-pressure accumulator will be released instantaneously, which will produce impact vibration and noise. The rupture of air bubbles in the oil will intensify this effect, which may cause the loosening of connecting bolts, the rupture of hydraulic elements and pipes, and even cause serious oil leakage of the equipment, thereby having an important impact on the stable operation, reliability and service life of the entire heavy equipment.

[0004] A high-pressure super large flow hydraulic system proportional pressure relief unloading method and system are disclosed in Chinese patent CN119412394A. Although this patent solves the above problems, it has the problems of complex system piping, dispersed element arrangement, and control valve 11 reversing only controls the on-off of cartridge valve 8, and cannot realize multi-stage pressure control.

[0005] Secondly, in the multi-stage pressure control hydraulic system, the remote control port of the remote unloading valve is usually connected to the oil inlet of three remote pressure regulating valves (direct-acting relief valves) with different pressures through a three-position four-way electromagnetic directional valve. When the electromagnetic directional valve is reversed and is in left, middle and right positions respectively, the pressure controlled by the remote unloading valve is the pressure regulated by the three remote pressure regulating valves respectively, realizing high-low multi-stage pressure control.

[0006] A digital logic multi-stage remote pressure regulating circuit is disclosed in Chinese patent CN210799555U. Although this patent can realize multi-stage remote pressure regulation, the regulated pressure is stepwise and not linearly proportional, and there are too many remote pressure regulating valves, which is too high in cost. SUMMARY

[0007] The present application aims to provide a relief proportional overflow valve which can reduce impact vibration, reduce noise, improve system stability and reliability, prolong system service life, simplify oil pipe arrangement, optimize component arrangement, meet proportional pressure control, reduce cost and improve product market competitiveness.

[0008] To solve the above technical problems, the present application provides a relief proportional overflow valve, which comprises a valve body, one end of the valve body is sequentially connected with a first cover plate and a second cover plate; a safety valve is integrated on the first cover plate, a pressure sensor, an electromagnetic overflow valve and an amplifier are integrated on the valve body; a lining ring is connected to the lower end surface of the second cover plate, a spring cavity C is arranged in the second cover plate; a valve sleeve is inserted into the lining ring, and the valve sleeve is attached to the inner end surface of the lining ring; a valve core is slidably arranged in the valve sleeve, a spring is arranged in the inner hole of the valve core, and one end of the spring extends into the spring cavity C; the electromagnetic overflow valve comprises an electromagnetic valve sleeve, and a pressure cavity P is arranged on the electromagnetic valve sleeve; a control oil port X and a control oil path Y are arranged on the second cover plate, control oil paths X1 and X2 are arranged on both sides of the spring cavity C; control oil paths X2, X3, X4, X5, Y1 and a return oil path T2 are arranged on the first cover plate; control oil paths X6 and a return oil path T1 are arranged on the valve body; the control oil port X is in communication with the control oil path X1, the control oil path X1 is in communication with the control oil paths X2 and X3, the control oil path X3 is in communication with the spring cavity C, the control oil path X2 is in communication with the control oil paths X4 and X5, the control oil path X5 is in communication with the control oil path X6 and the pressure cavity P, the pressure cavity P is in communication with the return oil paths T1 and T2, the control oil paths Y1 and Y2, and the control oil path Y, and the control oil path Y2 is in communication with the control oil path Y.

[0009] It also comprises a valve block for integrally mounting the valve body, the first cover plate, the second cover plate, the lining ring, the valve sleeve, the valve core and the spring, and an oil inlet A and a discharge port B are arranged on the valve block.

[0010] a first damping screw plug and a second damping screw plug are arranged in the first cover plate, a first damping hole z1 is arranged on the first damping screw plug, and a second damping hole z2 is arranged on the second damping screw plug; the first damping hole z1 is used for connecting the control oil path X3 and the spring cavity C, and the second damping hole z2 is used for connecting the control oil paths X1, X2 and X3.

[0011] The electromagnetic overflow valve comprises an electromagnetic valve seat, which is mounted in the valve body; the electromagnetic valve sleeve is sleeved on the outer side of the electromagnetic valve seat, and a conical valve core is slidably arranged in the electromagnetic valve sleeve; one end of the electromagnetic valve sleeve is connected with an electromagnet, and the electromagnet works in cooperation with the conical valve core through a top rod; one end of the conical valve core is provided with a conical surface k which cooperates with the sharp edge K of the electromagnetic valve seat to seal, and the other end is in contact with the top rod of the electromagnet.

[0012] The electromagnetic 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.

[0013] The safety valve comprises a safety valve seat installed in the first cover plate, a ball head valve core slidingly arranged in the safety valve seat, and a safety valve sleeve sleeved with the safety valve seat; one end of the ball head valve core is provided with a tapered surface n matched with the sharp edge N of the safety valve seat and a damping groove z, and the other end is a ball head surface Q; an adjusting screw is threadedly connected in the safety valve sleeve, and a safety spring is arranged in the adjusting screw; one end of the safety spring is in contact with the ball head surface Q through the tapered surface of the safety spring seat, and the other end is connected with the adjusting screw through an adjusting gasket and a gasket.

[0014] The safety valve seat is provided with an inclined hole O, the safety valve sleeve is threadedly connected with the first cover plate, and the adjusting screw is locked with the safety valve sleeve through an open retainer ring and a lock nut (1610).

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

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

[0017] The first cover plate is further provided with a hexagonal screw plug and an internal hexagonal tapered screw plug for sealing the excess oil port, and the valve body is provided with a threaded hole for connecting a pressure measuring connector, which is sealed by a sealing screw plug in a non-pressure measuring state.

[0018] Compared with the prior art, the present application has the advantages of small volume, compact structure, small power loss, fast action, high integration and the like, and is particularly suitable for control and regulation of a large-flow hydraulic system; the flow damping is small, the through-flow capacity is large, and it is particularly suitable for large-flow occasions; due to the conical valve structure, the internal leakage is very small, and there is no jamming phenomenon; the action speed is fast, because the oil path is immediately connected when the valve core is slightly lifted due to the sealing and cutting of the tapered surface; in addition, the stroke of the valve core is small, the action is sensitive, and it is particularly suitable for high-speed opening occasions; the anti-pollution ability is strong, and the work is reliable.

[0019] The above description is only a summary of the technical scheme of the present application, in order to more clearly understand the technical means of the present application, the content of the specification can be implemented, and in order to make the above and other purposes, characteristics and advantages of the present application more obvious and easy to understand, the specific embodiments of the present application are described below. BRIEF DESCRIPTION OF DRAWINGS

[0020] One or more embodiments are illustrated by way of example in the figures that form a part of this disclosure and which demonstrate aspects of the embodiments. These exemplary illustrations are not limited to the accompanying drawings but encompass all techniques within the scope of the embodiments, in which:

[0021] Figure 1 is a longitudinal sectional structure schematic diagram of the electromagnetic overflow valve of the present application; Figure 2 is Figure 1 is a longitudinal sectional structure schematic diagram of the electromagnetic valve seat of the present application; Figure 3 is Figure 2 is a longitudinal sectional structure schematic diagram of the electromagnetic valve seat of the present application; Figure 4 is Figure 2 is a longitudinal sectional structure schematic diagram of the electromagnetic valve seat of the present application; Figure 5 is Figure 1 is a longitudinal sectional structure schematic diagram of the electromagnetic valve seat of the present application; Figure 6 is Figure 5 is a longitudinal sectional structure schematic diagram of the electromagnetic valve seat of the present application; Figure 7 is Figure 5 is a longitudinal sectional structure schematic diagram of the electromagnetic valve seat of the present application; Figure 8 is Figure 1 is a longitudinal sectional structure schematic diagram of the electromagnetic valve seat of the present application; Figure 9 is Figure 1 is a longitudinal sectional structure schematic diagram of the electromagnetic valve seat of the present application; Figure 10 is a schematic diagram of the principle of the present application.

[0022] In the figure: 1 - gasket ring, 2 - valve sleeve, 3 - valve core, 4 - spring, 5 - second cover plate, 6 - first damping screw, 7 - first cover plate, 8 - second damping screw, 9 - hexagonal screw, 10 - inner hexagonal taper screw, 11 - sealing screw, 12 - valve body, 13 - pressure sensor, 14 - electromagnetic overflow valve, 141 - electromagnetic valve seat, 142 - electromagnetic valve sleeve, 143 - tapered valve core, 144 - electromagnet, 145 - top rod, 15 - amplifier, 16 - safety valve, 161 - safety valve seat, 162 - ball head valve core, 163 - safety spring seat, 164 - safety spring, 165 - safety valve sleeve, 166 - adjusting screw, 167 - adjusting washer, 168 - washer, 169 - open blocking ring, 1610 - locking nut. DETAILED DESCRIPTION

[0023] In order to make the objectives, technical solutions and advantages of the present application clearer, the embodiments of the present application will be described in detail below with reference to the drawings. However, those skilled in the art can understand that, in the embodiments of the present application, many technical details are presented in order to make the readers better understand the present application. However, the technical solutions claimed by the present application can be implemented even without these technical details and various changes and modifications based on the following embodiments. The division of the following embodiments is for the convenience of description, and should not constitute any limitation on the specific implementation modes of the present application, and the embodiments can be combined and referenced with each other on the premise of no contradiction.

[0024] Embodiment 1 A is an oil inlet, B is an oil outlet, C is a spring cavity, X is a control oil port, Y is a return oil port, X1, X2, X3, X4, X5, X6 are control oil paths, P is a pressure cavity, T is an inclined hole, T1, T2 are return oil paths, Y1, Y2 are control oil paths, F is a large outer cylindrical surface of the valve seat 141, G is a small outer cylindrical surface of the valve seat 141, H is a threaded hole of the valve seat 141, I is an oil inlet small hole of the valve seat 141, K is a sharp edge of the oil inlet small hole I of the valve seat 141, k is a tapered surface of the tapered valve core 143, J is a helical groove on an outer cylindrical surface of the tapered valve core 143, and L is an outer cylindrical surface of the tapered valve core 143.

[0025] W1 is a large outer cylindrical surface of the valve seat 161, W2 is a small outer cylindrical surface of the valve seat 161, M is an inner hole cylindrical surface of the valve seat 161, O is an inclined hole of the valve seat 161, N is a sharp edge of the inner hole cylindrical surface, m is an outer cylindrical surface of the ball head valve core 162, n is a tapered surface of the ball head valve core 162, Q is a ball head surface of the ball head valve core 162, z is a damping groove of the ball head valve core 162, and P1 is a pressure cavity of the safety valve.

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

[0027] Specifically, the lining ring 1 is in cylindrical surface cooperation with the valve sleeve 2, and is centered by the large diameter, and the upper end surface of the valve sleeve 2 is in abutment with the inner end surface of the lining ring 1; the valve core 3 is in cylindrical surface cooperation with the valve sleeve 2, and is centered by the large diameter, and there is a gap between the two, the lower end surface and the sharp edge of the cylindrical surface of the valve core 3 are in cooperation with the tapered surface of the valve sleeve 2, and the tapered surface is sealed, the valve core 3 moves up and down in the valve sleeve 2, the cylindrical surface of the valve core 3 is provided with an equalizing groove, so that the valve core does not jam when moving up and down, and the cylindrical surface of the valve core 3 is also provided with a sealing ring groove, so that the oil drain port B is not communicated 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 lining ring 1, the valve sleeve 2 and the valve core 3 are inserted together into the valve block (not shown in the figure).

[0028] Further, the upper end surface of the lining ring 1 is in abutment with the lower end surface of the second cover plate 5, the second cover plate 5 is provided with a spring cavity C, the spring cavity C is an inner hole, the inner hole of the lining ring 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 way X1, the right end of the second cover plate 5 is provided with an oil return port Y and an oil return way Y2, and the upper end surface of the second cover plate 5 is in abutment with the lower end surface of the first cover plate 7 and is positioned by a cylindrical pin (not shown in the figure).

[0029] Further, the lower end surface of the first cover plate 7 is provided with a threaded hole at the center, which is used for assembling the first damping screw 6 and the second damping screw 8, the upper end of the first damping screw 6 is provided with a first damping hole z1, the diameter of the first damping hole z1 is 0.8, the lower end of the first damping screw 6 is provided with an inner hexagonal hole, the upper end of the second damping screw 8 is provided with a second damping hole z2, the diameter of the second damping hole z2 is 1, and the lower end of the second damping screw 8 is provided with an inner hexagonal hole. The first cover plate 7 is provided with a control oil way X2, a control oil way X3, a control oil way X4, a control oil way X5, and is also provided with an oil return way Y1 and an oil return way T2. Secondly, the control oil ways X2, X3, X4 and X5 are communicated with each other, and the oil return way T2 is communicated with the oil return way Y1. The left end of the first cover plate 7 is assembled with a hexagonal screw 9 and an inner hexagonal tapered screw 10 to seal the control oil way. The right end of the first cover plate 7 is also assembled with a safety valve 16.

[0030] Specifically, the upper end surface of the first cover plate 7 is attached to the lower end surface of the valve body 12, the valve body 12 is provided with a control oil passage X6 and a pressure chamber P, and the pressure chamber P is communicated with the control oil passage X6. The left end of the valve body 12 is provided with a threaded hole for pressure measurement, and a sealing screw plug 11 is used to seal the threaded hole when pressure measurement is not performed. The right end of the valve body 12 is assembled with an electromagnetic overflow valve 14, the large outer cylindrical surface F of the electromagnetic valve seat 141 is matched with the inner hole cylindrical surface of the valve body 12 for large diameter centering, the left end surface of the electromagnetic valve seat 141 is attached to the bottom surface of the inner hole of the valve body 12 for axial positioning of the electromagnetic valve seat 141 to 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 small hole I, and the threaded hole H is communicated with the oil inlet small hole I. The small outer cylindrical surface of the electromagnetic valve seat 141 is matched with the inner hole of the electromagnetic valve sleeve 142 for large diameter centering; the electromagnetic valve sleeve 142 is threadedly connected with the valve body 12, and the electromagnetic valve sleeve 142 is provided with an inclined hole T. The inner hole of the electromagnetic valve sleeve 142 is matched with the outer cylindrical surface L of the tapered valve core 143 for large diameter centering. The outer cylindrical surface L of the tapered valve core 143 is provided with a spiral groove J, the left end of the tapered valve core 143 is provided with a tapered surface k, and the tapered surface k is sealed with the pointed edge K of the oil inlet small hole I of the electromagnetic valve seat 141 to make the pressure chamber P not communicated with the inclined hole T. The right end of the tapered valve core 143 is attached to the top rod 145 of the electromagnetic iron 144.

[0031] Further, the upper end surface of the valve body 12 is attached to the amplifier 15, the pressure sensor 13 is assembled between the amplifier 15 and the valve body 12, and the pressure sensor 13 detects the pressure of the pressure chamber P. The valve body 12 is provided with a return oil passage T1, which is communicated with the inclined hole T and a return oil passage T2, respectively, and 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 is matched with the inner hole cylindrical surface of the first cover plate 7, and is large-diameter centered; 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, and a stepped end surface is arranged between the small outer cylindrical surface W2 and the large outer cylindrical surface W1 of the safety valve seat 161, which is in abutment with the bottom surface of the inner hole of the valve body 12 and is used for axial positioning of the safety valve seat 161 to prevent the safety valve seat 161 from moving axially left and right. The inner hole cylindrical surface M of the safety valve seat 161 is matched with the outer cylindrical surface m of the ball valve core 162, and is large-diameter centered; the tapered surface n of the ball valve core 162 is sealed with the sharp edge N tapered surface of the safety valve seat 161; the ball head surface Q of the ball valve core 162 is connected with the tapered surface of the safety spring seat 163; the safety spring seat 163 can be automatically centered due to the action of the ball head surface Q of the ball valve core 162. The safety spring 164 is connected to the right end of the safety spring seat 163; the adjusting washer 167 is connected to the right end of the safety spring 164; the washer 168 is connected to the right end of the adjusting washer 167; the safety spring 164, the adjusting washer 167 and the washer 168 are assembled in the inner hole of the adjusting screw 166, and the right end of the washer 168 is in abutment with the bottom surface of the inner hole of the adjusting screw 166. The adjusting screw 166 is threadedly connected with the safety valve sleeve 165, and is threadedly connected with the lock nut 1610; the open retainer 169 is assembled between the adjusting screw 166 and the lock nut 1610. The safety valve sleeve 165 is threadedly connected with the first cover plate 7, and 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 the electromagnetic overflow valve: When the electromagnet 144 has no current, the pressure oil at the left end of the electromagnetic valve seat 141 pushes the tapered valve core 143 to move rightward through the threaded hole H of the electromagnetic valve seat 141 and the oil inlet small hole I, the tapered surface k of the tapered valve core 143 is separated from the sharp edge K of the electromagnetic valve seat 141, the oil inlet small hole I of the electromagnetic valve seat 141 is in communication with the inclined hole T on the electromagnetic valve sleeve 142, the pressure oil flows through the inclined hole T, and the electromagnetic overflow valve 14 is opened. When the electromagnet 144 is electrified, an attractive force is generated to push the top rod 145 to move leftward, the top rod pushes the tapered valve core 143 to move leftward, the tapered surface k of the tapered valve core 143 is in abutment with the sharp edge K of the electromagnetic valve seat 141, the oil inlet small hole I of the electromagnetic valve seat 141 is not in communication with the inclined hole T on the electromagnetic valve sleeve 142, and the electromagnetic overflow valve 14 is closed.

[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 pressure oil outputted by the pump enters the oil inlet A, enters the control oil port X through the valve block (not shown in the figure), and then enters the control oil passage X1, enters the control oil passage X2 and the control oil passage X3 through the second damping hole z2 of the second damping screw plug 8, wherein the pressure oil of the control oil passage X3 is divided into two paths, one path enters the spring cavity C through the first damping hole z1 of the first damping screw plug 6, and the other path reaches the left end of the safety valve 16, when the pressure reaches the opening pressure of the safety valve 16, the safety valve 16 is opened, the pressure oil enters the return oil passage Y1, and then enters the return oil passage Y2 to the return oil port Y for overflow, the safety valve 16 protects the system, otherwise, when the pressure does not reach the opening pressure of the safety valve 16, the safety valve 16 is in a closed state.

[0038] The pressure oil entering the control oil passage X2 enters the pressure cavity P through the control oil passage X4, the control oil passage X5 and the control oil passage X6. The pressure sensor 13 detects the pressure in the pressure cavity P, gives a signal to the amplifier, and the amplifier gives a signal to the electromagnet, and the electromagnet generates suction. When the pressure in the pressure cavity P reaches the opening pressure of the electromagnetic overflow valve 14, the electromagnetic overflow valve 14 is opened, and the pressure oil in the pressure cavity P enters the return oil passage T1 and the return oil passage T2 through the inclined hole T in sequence, and then enters the return oil passage Y1 and the return oil passage Y2 to reach the return oil port Y for overflow. At this time, the spring cavity C is communicated with the return oil port Y, the product of the pressure of the oil inlet A and the cylindrical surface area of the valve core 3 is greater than the pre-tightening force of the spring 4, the valve core 3 moves upward, the cylindrical sharp edge of the valve core 3 is separated from the conical surface of the valve sleeve 2, the oil inlet A is communicated with the oil discharge port B, the pressure oil enters the oil discharge port B from the oil inlet A, and the system is unloaded. When the current increases, according to the working principle of the electromagnetic overflow valve 14, the electromagnetic overflow valve 14 is closed, the spring cavity C is not communicated with the return oil port Y, the pressure of the spring cavity C is the same as the pressure of the oil inlet A, under the action of the pressure of the spring cavity C and the pre-tightening force of the spring 4, the valve core 3 is pressed on the conical surface of the valve sleeve 2, the oil inlet A is not communicated with the oil discharge port B, and the system is not unloaded. In this way, the unloading pressure of the system is proportional to the opening pressure of the electromagnetic overflow valve, and is also proportional to the current of the electromagnet. When the system pressure is abnormal, the safety valve is opened, the spring cavity C is communicated with the return oil port Y, and the oil inlet A is communicated with the oil discharge port B, and the system is unloaded.

[0039] As described above, the safety valve, the electromagnetic overflow valve and the pressure sensor are integrated on the unloading overflow valve, the integration degree is high, the system piping is simplified, and the element arrangement is optimized, and the following effects are also possessed 1) The safety valve, the electromagnetic overflow valve and the pressure sensor are integrated on the unloading overflow valve, the integration degree is high, the system piping is simplified, and the element arrangement is optimized.

[0040] 2) The safety valve, the electromagnetic overflow valve and the pressure sensor are integrated on the unloading overflow valve, the integration degree is high, the installation space of the main machine is saved, and the cost of the main machine is reduced.

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

[0042] 4) The safety valve, electromagnetic overflow valve and pressure sensor are integrated on the unloading overflow valve, which reduces the pressure loss and energy consumption.

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

[0044] 6) The safety valve, electromagnetic overflow valve and pressure sensor are integrated on the unloading overflow valve. Due to the rapid response of the electromagnetic overflow valve and the protection of the safety valve, the stability and reliability of the system are improved, the service life of the system is improved, and the market competitiveness of the product is improved.

[0045] It can be understood by those skilled in the art that various changes can be made in form and details in practical application of the above embodiments without departing from the spirit and scope of the present application.

Claims

1. A proportional relief valve for unloading, characterized in that: 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 as described in claim 1, characterized in that: 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 as described in claim 1, characterized in that: 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 as described in claim 1, characterized in that: 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 as described in claim 4, characterized in that: 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 1, 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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