Load holding constant differential pressure reducing valve

Abstract

A load holding constant differential pressure reducing valve. It relates to the field of hydraulic technology. It comprises a valve body (1), a main hole (11) is opened on the valve body (1), a valve core (4) is movably arranged in the main hole, a step one (111), a step two (112) and a step three (113) are sequentially arranged in the main hole (11), so that P1 cavity, P2 cavity and Ls cavity are formed in the main hole; a step circle (1131) is opened at the tail end of the step three (113); three working sections are arranged on the valve core (4), which are an axle shoulder one (41), an axle shoulder two (42) and an axle shoulder three (43) in sequence, and a valve core middle hole (44); a valve core radial hole (411) is opened on the axle shoulder one (41), and the valve core radial hole (411) is communicated with the valve core middle hole (44) through a damping hole (441); the constant differential pressure reducing valve can realize the load holding function, the structure is more compact, the use is friendly, and the cost is low.

Description

Technical Field

[0001] This invention relates to the field of hydraulic technology, and more specifically to an improvement in the construction of a differential pressure reducing valve used in a directional valve of a load-sensitive multi-way valve system. Background Technology

[0002] In existing technologies, to ensure the stability of the operation of load-sensitive multi-way valves, a differential pressure reducing valve needs to be installed in the directional valve, such as... Figure 15-20 As shown, it has two working states: P1 port and P2 port are either on or off. Based on this... Figure 17 As can be seen from the hydraulic schematic diagram, one side of the valve is acted upon by the load pressure Ls at the outlet of the directional valve and the spring force, while the other side is acted upon by the inlet pressure P2 of the directional valve. Therefore, the pressure difference across the directional valve is determined by the spring force. When the opening of the main valve remains unchanged, the flow rate at the main valve remains basically unchanged, so that the flow rate of the control actuator is not affected by the load pressure. Therefore, the differential pressure reducing valve is also called a pressure compensator.

[0003] In the field of construction machinery, the stability of the hydraulic system under load is crucial to the safety and operational performance of the host machine. For example, in cranes and excavators, the hydraulic cylinders bear loads (such as the weight of the load or equipment components). When controlling the hydraulic cylinder's movement, if the pressure generated by the load on the cylinder exceeds the pressure provided by the hydraulic system (e.g., due to pump failure or a sudden increase in load), the mechanism may experience an overspeed descent when the valve opens under the load. To prevent uncontrolled movement due to load changes, users need to close the flow path from the load chamber to the supply chamber to maintain a constant load port pressure even when the inlet pressure suddenly decreases or the load suddenly increases. Clearly, existing technologies cannot meet the requirements of the aforementioned complex working conditions.

[0004] Based on the installation position of the differential pressure reducing valve (pressure compensator), it is mainly divided into pre-valve compensation and post-valve compensation. Under this basic concept, to overcome this complex working condition (such as boom drop), compared to multi-way valves with post-valve compensation, some existing technology manufacturers and R&D units have adopted technical measures to add additional check valve components to achieve load holding function. Examples include patent documents "CN113202832A, A Load Holding Plate-Type Multi-way Valve" and "CN 104806594A, A Multi-way Valve with Cylinder Load Holding Function". It should be said that the post-valve compensation measures adopted in the aforementioned two existing patent documents can, to some extent, meet the "actual complex working conditions". However, they suffer from the disadvantage of having many components (requiring a check valve to be installed on each of the two oil ports), resulting in a complex overall hydraulic flow channel structure and large volume. Summary of the Invention

[0005] To address the above-mentioned technical problems, this invention provides a load-maintaining differential pressure reducing valve based on the concept of "internal integration," which can stabilize the differential pressure when the system pressure changes, thereby achieving a proportional relationship between the working output flow and the opening of the main valve port.

[0006] The technical solution of the present invention is: a load-holding differential pressure reducing valve, comprising a valve body, a main hole being provided on the valve body, a valve core being movably disposed in the main hole, and a step one, a step two, and a step three being provided sequentially in the main hole, so that a P1 cavity, a P2 cavity, and an Ls cavity are formed in the main hole; a step circle is provided at the tail end of the step three.

[0007] The valve core has three working sections, namely shoulder one, shoulder two and shoulder three, and valve core central hole; a valve core radial channel is opened on shoulder one, and the valve core radial channel is connected to the valve core central hole through a damping hole;

[0008] The shoulder is lengthened so that when the main valve core is in the initial position, the shoulder is adapted to the position of the step, so as to shut off the connection between the P1 chamber and the P2 chamber.

[0009] Furthermore, a switch switching mechanism is provided in the central hole of the valve core. The switch switching mechanism includes a spring seat fixedly disposed at the bottom end of the central hole of the valve core, a switch valve core movably disposed in the central hole of the valve core, and a return spring disposed between the spring seat and the switch valve core. A blind hole with its opening facing the damping hole is provided on the switch valve core, and a radial hole of the switch valve core is provided at the bottom of the blind hole.

[0010] The depth of the stepped circle is adapted to the position of the blind hole facing the bottom radial hole of the switch valve core, so that when the bottom end face of the stepped circle coincides with the axial position of the end of the axial channel, the edge of the radial hole of the switch valve core also coincides with the position of the working end face, thereby realizing the oil circuit switching.

[0011] Furthermore, at least two axial grooves are symmetrically formed on the surface of the shoulder three of the valve core.

[0012] Furthermore, the end face of the valve core shoulder three is the working end face, and a flange is provided on the working end face. The flange has an outer chamfer and a spiral drainage groove is provided on the flange.

[0013] Furthermore, the spiral drainage grooves are evenly distributed on the flange, with at least two grooves, and are Archimedean spirals.

[0014] Furthermore, the switch valve core and the valve core bore are fitted with a clearance to ensure that they can slide back and forth axially.

[0015] The invention firstly lengthens the shoulder, so that in the initial position, the shoulder cuts off the connection between the P1 and P2 chambers; thus, when the load suddenly increases, the hydraulic oil in the cylinder cannot be unloaded through the P1 port, so the pressure at the load end remains unchanged, and the weight maintains its previous height and does not fall.

[0016] Secondly, a switching mechanism is installed inside the valve core's central hole. The axially "positioning" switching valve core inside the valve core ensures that its axial position does not change when the valve core performs axial reciprocating motion. An oil passage is opened on the corresponding sinking working end face of the switching valve core, forming a timely switching node. That is to say, once the valve core moves to this position, the working state is switched. This avoids the valve core being locked if the passage closes prematurely, and the valve core's right end taking an inaccurate value if it closes late.

[0017] This invention pertains to a multi-way valve with pre-valve compensation. It innovatively improves the structure of the original differential pressure reducing valve. The improved differential pressure reducing valve can achieve load holding function, has a more compact structure, is user-friendly, and has low cost. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the structure of the present invention. Figure 1 (Work Status 1)

[0019] Figure 2 This is a schematic diagram of the structure of the present invention. Figure 2 (Work Status Two)

[0020] Figure 3 This is a schematic diagram of the structure of the present invention. Figure 3 (Work Status 3)

[0021] Figure 4 This is a hydraulic schematic diagram of the present invention;

[0022] Figure 5 This is a three-dimensional schematic diagram of the valve body in this invention.

[0023] Figure 6 This is a schematic diagram of the valve body in this invention;

[0024] Figure 7 This is a three-dimensional schematic diagram of the valve core in this invention.

[0025] Figure 8 This is a front view of the valve core in this invention.

[0026] Figure 9 yes Figure 8 Left view,

[0027] Figure 10 yes Figure 9 Sectional view AA

[0028] Figure 11 yes Figure 10 Enlarged view of a section at point B in the middle;

[0029] Figure 12 This is a three-dimensional schematic diagram of the switching valve core in this invention.

[0030] Figure 13 This is a schematic diagram of the structure of the switching valve core in this invention;

[0031] Figure 14 This is a schematic diagram of the working principle of the present invention;

[0032] Figure 15 This is a structural schematic diagram of the background technology of the present invention. Figure 1 (Work Status 1)

[0033] Figure 16 This is a structural schematic diagram of the background technology of the present invention. Figure 2 (Work Status 2)

[0034] Figure 17 This is a hydraulic principle diagram of the background technology of this invention;

[0035] Figure 18 This is a schematic diagram of the valve body in the background art of this invention.

[0036] Figure 19 This is a schematic diagram of the main valve core in the background art of this invention.

[0037] Figure 20 This is a perspective view of the main valve core in the background technology of this invention.

[0038] In the diagram, 1 is the valve body, 11 is the main hole, 111 is step one, 112 is step two, 113 is step three, and 1131 is the step circle;

[0039] 2 is the plug; 3 is the spring;

[0040] 4 is the valve core, 41 is shoulder one, 411 is the radial channel of the valve core, 42 is shoulder two, 43 is shoulder three, 431 is the axial channel, 44 is the valve core central hole, 441 is the damping hole, 45 is the working end face, 451 is the flange, and 4511 is the helical drainage groove.

[0041] 5 is the spring seat; 6 is the return spring;

[0042] 7 is the on / off valve core, 71 is the blind hole, and 72 is the radial hole of the on / off valve core;

[0043] K1~K6 are channels one through six;

[0044] 'a' indicates switching to a different trip;

[0045] Figure 1 ,2 The arrows in section 14 indicate the direction of hydraulic oil movement. Figure 14 The hollow arrow indicates the direction of valve core movement. Detailed Implementation

[0046] Before describing the specific embodiments of the present invention, in conjunction with the accompanying drawings... Figure 15-20 The working principle of a conventional differential pressure reducing valve is explained below (the conventional structure of each component is not described in detail in this case):

[0047] When the spring is installed, it is in a compressed state. A preload F is set. Under the action of the spring preload, the valve core 4 of the differential pressure reducing valve is at its rightmost end. Chambers P1 and P2 are connected. When the system starts supplying oil, the hydraulic oil in chamber P2 reaches the right end of the valve core of the differential pressure reducing valve via the radial hole, damping hole, and center hole (e.g., ...). Figure 15 As indicated by the middle arrow, under the pressure of hydraulic oil, the valve core 4 of the differential pressure reducing valve tends to move to the left. The Ls chamber is connected to the load port, providing feedback on the load pressure. When the force at the left end of the valve core (spring force and Ls pressure) is less than the force at the right end (P2 chamber pressure), the valve core moves to the left, increasing the valve opening. When the opening decreases to a certain extent, step two on the valve body and shoulder two on the valve core close, closing the valve. When the force at the left end of the valve core (spring force and Ls pressure) is greater than the force at the right end (P2 chamber pressure), the valve core moves to the right again, opening the valve. When the main valve core opening remains unchanged, and the load pressure changes, the valve core moves accordingly to the left and right within the valve body, adjusting the pressure difference before and after the main valve core port, ensuring the load flow is unaffected. However, during normal operation, the forces at both ends of the differential pressure reducing valve core remain in a balanced state. When the load end pressure (Ls chamber pressure) suddenly increases, the differential pressure reducing valve core moves to the rightmost end. Since the valve port is open at this time, the load end pressure will be relieved through the P2 chamber, valve port, and P1 port, and the load holding function cannot be achieved.

[0048] Therefore, the core technical task of this invention is to innovatively improve the conventional differential pressure reducing valve so that it can achieve load holding function. To better understand the technical essence and beneficial effects of this invention, the applicant provides a detailed description below using embodiments. However, the description of the embodiments is not intended to limit the scope of this invention, and any formal, rather than substantive, equivalent modifications made based on the inventive concept should be considered within the scope of this invention.

[0049] In the following description, all directional or positional concepts involving up, down, left, right, front, and back are based on... Figure 1 , 2The position and state of 3 are used as examples, and therefore should not be construed as a special limitation on the technical solution provided by the present invention.

[0050] Furthermore, to facilitate a clear understanding of the technical content of this invention by those skilled in the art, different reference numerals are used for structural features and functional features in this invention. This is explained below:

[0051] Channel 1 K1: This is a dynamic channel. When the valve core 4 is at the right end, the P1 cavity connects to the axial channel 431 and "flips over" the flange 451 through the spiral drainage groove 4511. The pressure of the hydraulic oil acts on the sinking working end face 45 of the valve core 4, giving the valve core 4 a hydraulic driving force in the left direction, driving the valve core 4 to move to the left.

[0052] Channel 2 K2: This is a static physical channel, namely the radial channel 411 of the valve core;

[0053] Channel 3 K3: This is a static physical channel, which is the central hole of spring seat 5 (connecting damping hole 441 and valve core central hole 44). This feature is not marked in the attached drawing.

[0054] Channel 4 K4: This is a dynamic channel, controlled by the middle shoulder 2 42 of valve core 4. When valve core 4 moves to the left or right, the cooperation between shoulder 2 42 and step 2 112 realizes the connection and disconnection between P1 and P2 chambers.

[0055] Channel 5 K5: This is a static physical channel, namely the blind hole 71 of the switch valve core;

[0056] Channel 6 K6: This is a static physical channel, which is the radial hole 72 of the valve core.

[0057] The present invention provides a load-holding differential pressure reducing valve, such as... Figure 1-14 As shown, the valve includes a valve body 1, a main hole 11 is provided on the valve body 1, a valve core 4 is movably disposed in the main hole 11, and a step 111, a step 2 112 and a step 3 113 are provided in sequence in the main hole 11, so that the main hole forms a P1 cavity, a P2 cavity and an Ls cavity; a step circle 1131 is provided at the tail end of the step 3 113.

[0058] Of course, the valve body 1 is also equipped with a plug 1 and a spring 3 for pre-pressure.

[0059] The valve core 4 is provided with three working sections, namely shoulder 1 41, shoulder 2 42 and shoulder 3 43, and valve core central hole 44; a valve core radial channel 411 is provided on shoulder 1 41, and the valve core radial channel 411 is connected to the valve core central hole 44 through a damping hole 441.

[0060] The shoulder 41 is lengthened so that when the main valve core 4 is in the initial position (with Figure 1-3For example, the right end) shoulder 41 and step 112 are matched to shut off the connection between cavity P1 and cavity P2;

[0061] Furthermore, a switching mechanism is provided in the valve core bore 44. The switching mechanism includes a spring seat 5 fixedly disposed at the bottom end of the valve core bore 44, a switching valve core 7 movably disposed in the valve core bore 44, and a reset spring 6 disposed between the spring seat 5 and the switching valve core 7. A blind hole 71 with its opening facing the damping hole 441 is provided on the switching valve core 7, and a switching valve core radial hole 72 is provided at the bottom of the blind hole 71.

[0062] The depth of the stepped circle 1131 is matched with the position of the blind hole 71 facing the bottom of the switch valve core radial hole 72, so that when the bottom end face of the stepped circle 1131 coincides with the axial position of the end of the axial channel 42, the edge of the switch valve core radial hole 72 also coincides with the position of the working end face 45, thereby realizing the oil circuit switching.

[0063] Furthermore, at least two axial grooves 431 are symmetrically formed on the surface of the shoulder 43 of the valve core 4. This facilitates the rapid flow of hydraulic oil in the P1 chamber and prevents adhesion between the shoulder 43 and the step 113.

[0064] Furthermore, the end face of the shoulder 3 43 of the valve core 4 is a working end face 45, and a flange 451 is provided on the working end face 45. The flange 451 has an outer chamfer, and a helical drainage groove 4511 is provided on the flange 451. This allows the P1 cavity to be connected to the sunken working end face 45 through the axial channel 431, the stepped circle 1131, and the helical drainage groove 4511 when the valve core 4 is at the right end, thus providing the valve core 4 with a hydraulic driving force in the left direction and driving the valve core 4 to move to the left.

[0065] Furthermore, the spiral drainage grooves 4511 are evenly distributed on the flange 451, with at least two grooves, which are Archimedean spirals.

[0066] Furthermore, the switch valve core 7 is clearance-fitted with the valve core bore 44 to ensure that they can slide back and forth axially.

[0067] The working principle of this invention is explained below using the example of a multi-way valve controlling a hydraulic cylinder to lift a heavy object:

[0068] Power-on status Figure 1 As shown (corresponding to hydraulic principle) Figure 4Under the force of spring 3, the valve core 4 of the differential pressure reducing valve is located at the rightmost end. When the hydraulic system supplies oil, oil enters through port P1 and passes through orifice K1 on the valve core 4 to the right end face of the valve core 4, pushing the valve core 4 to move to the left against the spring force of spring 3 until the valve port is opened. The hydraulic oil flows through orifice K4 to the P2 chamber, and the pressure becomes P2. When the forces at the left and right ends of the valve core 4 are balanced, the valve core 4 remains in the open state.

[0069] Open state (multi-way valve controls the hydraulic cylinder to work normally) such as Figure 2 As shown (corresponding to the principle) Figure 4 (In the middle position), orifice K1 is closed. Under the thrust of the return spring 6, the switch valve core 7 remains at the rightmost end. Hydraulic oil in chamber P2 flows through orifices K2, K3, K5, and K6 to the right end of the differential pressure reducing valve core 4. If the load pressure decreases (Ls pressure decreases), the force at the right end of the differential pressure reducing valve core 4 is greater than the force at its left end. The main valve core 4 moves to the left, and the flow area of ​​orifice K4 decreases. When the force at the right end of the differential pressure reducing valve core 4 reaches a certain level, orifice K4 closes, and the state is as follows. Figure 3 As shown (corresponding to the principle) Figure 4 (Right position). When the main valve core opening of the valve body remains unchanged, and the load pressure changes, the valve core of the differential pressure reducing valve moves to the left and right within the valve body 1 accordingly, adjusting the pressure difference before and after the main valve core port so that the load flow is not affected.

[0070] When a heavy object is suddenly added, i.e., the load suddenly increases, the sum of the force of the spring 3 on the left side of the differential pressure reducing valve core 4 and the Ls pressure is greater than the force on its right side (the pressure of P2). At this time, the conventional differential pressure reducing valve core is at the rightmost end, and the step 112 on the valve body and the shoulder 42 on the differential pressure reducing valve core 4 are not closed (the differential pressure reducing valve port is open). The hydraulic oil in the load port, P1 port, and P2 port is connected, forming a phenomenon of unloading at the load port, causing the heavy object to fall rapidly, which poses a certain danger. However, in the differential pressure reducing valve improved in this invention, the sum of the Ls pressure (pressure at the load) and the spring force is higher than the P2 port pressure. The force on the left end of the differential pressure reducing valve core 4 is greater than the force on its right end. The differential pressure reducing valve core 4 moves to the right, the fourth orifice K4 closes, the second orifice K2, the third orifice K3, the fifth orifice K5, and the sixth orifice K6 close, and the first orifice K1 opens. The structural state is as follows. Figure 1 As shown (corresponding to the principle) Figure 4 (Left position) The step 112 on the valve body and the shoulder 41 on the valve core 4 of the differential pressure reducing valve are in the closed state (the valve port of the differential pressure reducing valve is closed). The load port is connected to the P2 port, but not to the oil inlet P1. The hydraulic oil in the cylinder cannot be unloaded through the P1 port, so the pressure at the load end remains unchanged, and the weight maintains its previous height and will not drop.

[0071] This invention adds a load pressure holding function while keeping the original differential pressure reducing valve function unchanged (when the valve opening is unchanged, the flow rate at the valve port is basically unchanged).

[0072] When the pressure P1 suddenly decreases, under the pressure of Ls (load pressure) and the force of spring 3, the valve core 4 of the differential pressure reducing valve moves to the right, closing orifice 4 (k4), orifices 2 (k2), 3 (k3), 5 (k5), and 6 (k6), while orifice 1 (k1) opens, thus achieving the load holding function. To achieve this function, it is important to note that during the left-right movement of the valve core 4, the opening (closing) of orifice 1 (k1) and the closing (opening) of orifices 2 (k2), 3 (k3), 5 (k5), and 6 (k6) should occur simultaneously. If orifice 1 (k1) closes prematurely, a closed cavity is formed at the right end of the valve core 4, preventing it from moving to the right. If orifice 1 (k1) closes late, due to pressure loss, the pressure in cavity P1 is higher than the pressure in cavity P2, resulting in the pressure at the right end of the valve core 4 being the pressure in cavity P1, which is not accurate enough.

[0073] This invention is not limited to the above embodiments. Based on the technical solutions disclosed in this invention, those skilled in the art can make some substitutions and modifications to some of the technical features without creative effort, and all such substitutions and modifications are within the protection scope of this invention.

Claims

1. A load-holding differential pressure reducing valve, comprising a valve body (1), a main hole (11) is provided on the valve body (1), a valve core (4) is movably disposed in the main hole, and a step one (111), a step two (112) and a step three (113) are sequentially provided in the main hole (11), so that a P1 cavity, a P2 cavity and an Ls cavity are formed in the main hole; a step circle (1131) is provided at the tail end of the step three (113). The valve core (4) is provided with three working sections, namely, shoulder one (41), shoulder two (42), and shoulder three (43), and valve core central hole (44); a valve core radial channel (411) is provided on shoulder one (41), and the valve core radial channel (411) is connected to the valve core central hole (44) through a damping hole (441); characterized in that, At least two axial grooves (431) are symmetrically opened on the surface of the shoulder three (43) of the valve core (4); the end face of the shoulder three (43) of the valve core (4) is the working end face (45). The shoulder (41) is lengthened so that when the valve core (4) is in the initial position, the shoulder (41) is adapted to the position of the step (112) to shut off the connection between the P1 cavity and the P2 cavity; Furthermore, a switch switching mechanism is provided in the valve core bore (44), the switch switching mechanism includes a spring seat (5) fixedly disposed at the bottom end of the valve core bore (44), a switch valve core (7) movably disposed in the valve core bore (44), and a reset spring (6) disposed between the spring seat (5) and the switch valve core (7); a blind hole (71) with its opening facing the damping hole (441) is provided on the switch valve core (7), and a switch valve core radial hole (72) is provided at the bottom of the blind hole (71); The depth of the stepped circle (1131) is adapted to the position of the blind hole (71) facing the bottom of the switch valve core radial hole (72) of the switch valve core (7), so that when the bottom end face of the stepped circle (1131) coincides with the axial position of the end of the axial channel (431), the edge of the switch valve core radial hole (72) also coincides with the position of the working end face (45), thereby realizing the oil circuit switching.

2. The load-holding differential pressure reducing valve according to claim 1, characterized in that, The working end face (45) is provided with a flange (451), the flange (451) is provided with an outer chamfer, and a spiral channel (4511) is provided on the flange (451).

3. The load-holding differential pressure reducing valve according to claim 2, characterized in that, The spiral drainage grooves (4511) are evenly distributed on the flange (451), with at least two grooves, which are Archimedean spirals.

4. The load-holding differential pressure reducing valve according to claim 1, characterized in that, The switch valve core (7) is fitted with the valve core hole (44) with a clearance to ensure that they can slide back and forth axially.

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