Load-sensitive regulating unit and load-sensitive valve group

Abstract

The utility model relates to a load sensitive technical field, concretely relates to a load sensitive regulation and control unit and load sensitive valve group, the load sensitive regulation and control unit includes the main control valve and pilot control valve, and the pilot control chamber of main control valve is provided with the hydraulic pressure by pilot control valve corresponding, and pilot control valve includes movable valve sleeve and pilot valve core, and movable valve sleeve is slidably arranged on pilot valve core, and one end of movable valve sleeve is equipped with valve sleeve spring, and the load pressure of the working mouth of main control valve can be used for prompting movable valve sleeve of pilot control valve to move towards the direction of connecting internal pilot oil circuit, and the hydraulic pressure of the oil inlet of main control valve can be used for prompting movable valve sleeve of pilot control valve to move towards the direction of closing internal pilot oil circuit, the utility model provides a load sensitive regulation and control unit, and the pilot sensitive auxiliary regulation and control based on pilot control valve sleeve movement are proposed, guarantee the stability of main control valve flow output, and the load response speed and efficiency of system are improved.

Description

Technical Field

[0001] This utility model relates to the field of load-sensitive technology, specifically to a load-sensitive control unit and a load-sensitive valve assembly. Background Technology

[0002] A load-sensitive system is a hydraulic control system that automatically adjusts output pressure and flow rate according to changes in external load. By detecting changes in load pressure in real time, the system dynamically adjusts the output power of the load-sensing pump, thereby achieving energy supply that matches load demand and features energy saving and high efficiency.

[0003] In load-sensitive systems, pressure compensation is a key technical aspect to ensure stable system operation. Currently, the main methods employed include pre-valve pressure compensation, post-valve pressure compensation, and series-parallel combination compensation. However, existing load-sensitive systems all use a single compensation valve core for control, which still suffers from insufficient control performance, such as low control accuracy and control delay, in high-frequency variable load control applications. Utility Model Content

[0004] To address the technical problem of insufficient control performance in existing load-sensitive systems, this invention proposes a load-sensitive control unit. It proposes pilot-sensitive auxiliary control based on the movement of the pilot control valve sleeve, which ensures the stability of the main control valve's flow output during load fluctuations and improves the system's load response speed and efficiency.

[0005] The technical solution of this utility model:

[0006] A load-sensitive control unit, comprising:

[0007] The main control valve, wherein the pilot control chamber of the main control valve is supplied with hydraulic pressure by a corresponding pilot control valve;

[0008] A pilot control valve, comprising a movable valve sleeve and a pilot valve core, wherein the movable valve sleeve is slidably disposed on the pilot valve core, and a valve sleeve spring is provided at one end of the movable valve sleeve;

[0009] The load pressure at the working port of the main control valve can be used to cause the movable valve sleeve of the pilot control valve to move in the direction of connecting the internal pilot oil circuit; the hydraulic pressure at the oil inlet P of the main control valve can be used to cause the movable valve sleeve of the pilot control valve to move in the direction of closing the internal pilot oil circuit.

[0010] Furthermore, the main control valve includes two pilot control chambers, and there are two corresponding pilot control valves; the main control valve includes a first working port A and a second working port B, and the load-sensitive control unit further includes a first shuttle valve, the first inlet and the second inlet of the first shuttle valve are respectively connected to the first working port A and the second working port B of the main control valve, and the hydraulic pressure at the outlet of the first shuttle valve is the load pressure.

[0011] Furthermore, the movable valve sleeve is also connected to a drive sleeve via a limiting pin, and the drive sleeve is located radially outside the movable valve sleeve; the pilot control valve also includes a valve body, and the valve body is provided with a first drive oil passage a and a second drive oil passage b at both ends of the drive sleeve, the first drive oil passage a is used to connect to the load pressure of the working port of the main control valve, and the second drive oil passage b is used to connect to the oil inlet P of the main control valve.

[0012] Furthermore, the valve body has an oil inlet passage c at one end of the movable valve sleeve that connects to the oil inlet P' of the pilot control valve, and a pressure equalization chamber d is formed at the other end of the movable valve sleeve. The movable valve sleeve has a pressure equalization damping hole connecting its two ends. The middle part of the movable valve sleeve has an oil outlet passage e that connects to the oil outlet of the pilot control valve. The outer side wall of the pilot valve core has an oil guide groove for connecting and closing the oil inlet passage c and the oil outlet passage e.

[0013] Furthermore, the load-sensitive control unit also includes a second shuttle valve. The load pressure at the working port of the main control valve is connected to the first inlet of the second shuttle valve, the oil inlet pressure of the main control valve is connected to the second inlet of the second shuttle valve, and the outlet of the second shuttle valve is connected to the load-sensitive interface Ls via a check valve.

[0014] Furthermore, the main control valve's inlet P is also equipped with a hydraulic compensation valve, the hydraulic compensation valve's inlet IN is used to connect to pressurized oil, and the hydraulic compensation valve's outlet is connected to the main control valve's inlet P; the first end of the hydraulic compensation valve's valve core is equipped with a return spring, the first end of the hydraulic compensation valve's valve core is also connected to the load pressure of the main control valve's working port, and the second end of the hydraulic compensation valve's valve core is connected to the hydraulic compensation valve's outlet via damping.

[0015] In another aspect, this utility model provides a load-sensitive valve assembly, comprising N load-sensitive control units as described in any one of the above, wherein N is an integer greater than or equal to 2.

[0016] Furthermore, the load-sensitive valve assembly includes a flow distribution valve and a priority valve. The inlet IN of the flow distribution valve is connected to the outlet of the load-sensing pump. The first outlet OUT1 of the flow distribution valve is connected to the inlet of the priority valve. The outlet of the priority valve is connected to one of the load-sensitive control units for oil supply. The second outlet OUT2 of the flow distribution valve is connected to other load-sensitive control units for oil supply. The inlet of the priority valve is connected to one end of the valve core of the flow distribution valve, and the outlet of the priority valve is connected to the other end of the valve core of the flow distribution valve. When the flow distribution valve is in its initial position, the inlet IN of the flow distribution valve is connected to the first outlet OUT1.

[0017] Furthermore, N is an integer greater than or equal to 3;

[0018] Each load-sensitive control unit includes a main control valve with a first auxiliary port U1, a second auxiliary port U2, a third auxiliary port U3, and a fourth auxiliary port U4. The first auxiliary port U1 is connected to the inlet of the hydraulic compensation valve. When the main control valve is in the neutral position, the first auxiliary port U1 is connected to the second auxiliary port U2, and the third auxiliary port U3 is connected to the fourth auxiliary port U4.

[0019] In the first load-sensitive control unit, the first auxiliary oil port U1 of the main control valve is connected to the oil outlet of the priority valve, the fourth auxiliary oil port U4 of the main control valve is connected to the second oil outlet OUT2 of the flow distribution valve via the first auxiliary check valve, and the second auxiliary oil port U2 of the main control valve is connected to the third auxiliary oil port U3 when the main control valve is in the neutral position.

[0020] The second outlet OUT2 of the flow distribution valve is sequentially connected to the first auxiliary port U1 and the second auxiliary port U2 of the main control valve in the second to Nth load-sensitive control units; when the second to N-1th main control valves are in the neutral position, their second auxiliary port U2 and third auxiliary port U3 are not connected; when the Nth main control valve is in the neutral position, its second auxiliary port U2 is connected to the third auxiliary port U3; the fourth auxiliary port U4 of the Nth main control valve is sequentially connected to the third auxiliary port U3 and the fourth auxiliary port U4 of the N-1th to 2nd main control valves; the fourth auxiliary port U4 of the 2nd main control valve is connected to the outlet of the priority valve via the second auxiliary check valve.

[0021] Furthermore, in the third to Nth load-sensitive control units, at least one main control valve's first auxiliary oil port U1 is connected to the flow distribution valve's second oil outlet OUT2 via a two-way solenoid valve.

[0022] By adopting the above technical solution, the load-sensitive control unit and load-sensitive valve assembly provided by this utility model have the following advantages compared with the prior art:

[0023] 1. The load-sensitive control unit provided by this utility model includes a main control valve and a pilot control valve. The movable valve sleeve in the pilot control valve has a compensation function for small distance fluctuations with load pressure. It can quickly convert load fluctuations into micro-displacement signals of the valve core of the main control valve, and fine-tune the valve opening of the main control valve to ensure the stability of the output flow and prevent the problem of sudden instability of the actuator due to load fluctuations. It has high control accuracy and fast control response speed.

[0024] 2. The load-sensitive control unit provided by this utility model is also equipped with a hydraulic compensation valve at the inlet of the main control valve to realize pressure compensation, ensure the constant pressure difference between the inlet and outlet of the main control valve, and improve the control characteristics of the required flow rate; together with the valve port fine adjustment of the main control valve, it realizes the coordinated compensation control of pressure and valve port dual compensation, further improving the load response speed and efficiency.

[0025] 3. The load-sensitive system provided by this utility model can realize priority oil supply to specific actuators, as well as sequential or active oil supply to other actuators. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the load-sensitive control unit in Embodiment 1;

[0027] Figure 2 This is a schematic diagram of the pilot control valve in Example 1;

[0028] Figure 3 This is a schematic diagram of the load-sensitive valve assembly in Example 2.

[0029] in,

[0030] Load-sensitive control unit 100, load-sensitive valve assembly 200;

[0031] Main control valve 1; pilot control valve 2, movable valve sleeve 21, equalizing damping orifice 211, valve sleeve spring 22, pilot valve core 23, transmission hole 231, valve core spring 232, drain hole 233, guide groove 234, flow groove 235, valve seat 24, limit pin 25, drive sleeve 26, valve body 27, first valve body 271, second valve body 272, third valve body 273, fourth valve body 274; first shuttle valve 3; second shuttle valve 41, check valve 42; hydraulic compensation valve 5, return spring 51, damping 52; overflow replenishment valve assembly 6; flow distribution valve 71, priority valve 72, two-way solenoid valve 73; first auxiliary check valve 81, second auxiliary check valve 82; pilot pressure reducing valve 91, filter 92, safety valve assembly 93. Detailed Implementation

[0032] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present utility model or its application or use. All other embodiments obtained by those skilled in the art based on the embodiments of the present utility model without creative effort are within the scope of protection of the present utility model.

[0033] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0034] Furthermore, it should be noted that the use of terms such as "first" and "second" to define components is merely for the purpose of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore cannot be construed as limiting the scope of protection of this utility model.

[0035] Example 1:

[0036] like Figure 1-2 As shown, this embodiment provides a load-sensitive control unit 100, which includes a main control valve 1 and a pilot control valve 2. The main control valve 1 has at least one pilot control chamber, and the number of pilot control valves 2 corresponds one-to-one with the number of pilot control chambers. The pilot control valves 2 are used to provide hydraulic pressure to each pilot control chamber to realize the displacement control of the valve core of the main control valve 1.

[0037] For example, in this embodiment, the main control valve 1 is a three-position eight-way valve, which includes an inlet port P, a return port T, a first working port A, and a second working port B. The inlet port P is used to supply pressurized oil, the return port T is used to connect to the hydraulic oil tank, and the first working port A and the second working port B are used to connect to the actuator. The main control valve 1 includes upper and lower pilot control chambers, which are respectively supplied with hydraulic pressure by two pilot control valves 2. When the main control valve 1 is in the first position, i.e., the middle position in the figure, the inlet port P, the return port T, the first working port A, and the second working port B are blocked; when it is in the second position, i.e., the lower position in the figure, the inlet port P and the first working port A are connected, and the second working port B and the return port T are connected; when it is in the third position, i.e., the upper position in the figure, the inlet port P and the second working port B are connected, and the first working port A and the return port T are connected.

[0038] The pilot control valve 2 can be, but is not limited to, a proportional control valve. The pilot control valve 2 includes a pilot valve core 23, which moves under the action of electromagnetic force or other control forces to open and close the pilot oil circuit inside the pilot control valve 2. The pilot control valve 2 also includes a movable valve sleeve 21, which is slidably fitted onto the pilot valve core 23. One end of the movable valve sleeve 21 is also provided with a valve sleeve spring 22; for example, in this embodiment, the valve sleeve spring 22 is located at... Figure 2 The left end of the valve sleeve 21 enables micro-motion control.

[0039] Furthermore, the load-sensitive control unit 100 also includes a first shuttle valve 3. The first inlet and the second inlet of the first shuttle valve 3 are respectively connected to the first working port A and the second working port B of the main control valve 1. The higher pressure between the first working port A and the second working port B is taken as the load pressure. The oil outlet of the first shuttle valve 3 is led to one side of the movable valve sleeve 21 of the two proportional control valves. The hydraulic pressure of this oil can cause the movable valve sleeve 21 of the two pilot control valves 2 to move in the direction of opening their internal pilot oil circuits. The oil in the oil inlet P of the main control valve 1 is led to the other side of the movable valve sleeve 21 of the two pilot control valves 2. The hydraulic pressure of this oil can cause the movable valve sleeve 21 of the two pilot control valves 2 to move in the direction of closing their internal pilot oil circuits.

[0040] One side of the movable valve sleeve 21 is as follows Figure 2 The left side is subjected to the force of the valve sleeve spring 22 and the load pressure, while the other side is as follows: Figure 2 The right side is subjected to the oil pressure at the oil inlet P of the main control valve 1. In the initial state, the movable valve sleeve 21 is in the equilibrium position under force.

[0041] When the load pressure decreases, the force on the left side of the movable valve sleeve 21 is lower than that on the right side. The movable valve sleeve 21 moves to the left, causing the internal pilot oil passage to tend to close, i.e., its opening decreases. When the main control valve 1 is working, the openings of the two corresponding pilot control valves 2 are different. For example, when the main control valve 1 is working in the lower position, the opening of the pilot control valve 2 corresponding to the lower pilot control chamber is 0%, and the opening of the pilot control valve 2 corresponding to the upper pilot control chamber is m%. When the openings of both pilot control valves 2 decrease, the overall opening of the main control valve 1 still decreases. For example, when the main control valve 1 is working in the upper position, the opening of the pilot control valve 2 corresponding to the upper pilot control chamber is 0%, and the opening of the pilot control valve 2 corresponding to the lower pilot control chamber is m%. When the openings of both pilot control valves 2 decrease, the overall opening of the main control valve 1 still decreases. When the load pressure decreases, the pressure difference between the inlet and outlet of the main control valve 1 increases, according to the flow formula... It can be seen that when the pressure difference ΔP between the inlet and outlet of the main control valve 1 increases, appropriately reducing the opening area A can ensure the stability of the output flow rate, where C d ρ is the flow coefficient, and ρ is the oil density.

[0042] When the load pressure increases, the force on the left side of the movable valve sleeve 21 is greater than that on the right side. The movable valve sleeve 21 moves to the right, causing the internal pilot oil circuit to tend to connect, i.e., its opening degree increases. When the main control valve 1 is working, the opening degrees of the two corresponding pilot control valves 2 are different. For example, when the main control valve 1 is working in the lower position, the opening degree of the pilot control valve 2 corresponding to the lower pilot control chamber is 0%, and the opening degree of the pilot control valve 2 corresponding to the upper pilot control chamber is n%. When the opening degrees of both pilot control valves 2 increase, the opening degree of the pilot control valve 2 corresponding to the upper pilot control chamber increases more, and the overall opening degree of the main control valve 1 still increases. For example, when the main control valve 1 is working in the upper position, the opening degree of the pilot control valve 2 corresponding to the upper pilot control chamber is 0%, and the opening degree of the pilot control valve 2 corresponding to the lower pilot control chamber is n%. When the opening degrees of both pilot control valves 2 increase, the opening degree of the pilot control valve 2 corresponding to the lower pilot control chamber increases more, and the overall opening degree of the main control valve 1 still increases. When the load pressure increases, the pressure difference between the inlet and outlet of the main control valve 1 decreases, according to the flow formula. It can be seen that when the inlet and outlet pressure difference ΔP decreases, appropriately increasing the opening area A can ensure the stability of the output flow rate, where C d ρ is the flow coefficient, and ρ is the oil density.

[0043] Therefore, the load-sensitive control unit 100 provided in this embodiment has a movable valve sleeve 21 that has a small distance compensation function for load pressure fluctuations. It can quickly convert load fluctuations into a micro displacement signal of the valve core of the main control valve 1, and finely adjust the valve opening of the main control valve 1 to ensure the stability of the output flow and prevent the problem of sudden instability of the actuator due to load fluctuations. It has high control accuracy and fast control response speed.

[0044] In other embodiments, the main control valve 1 may have only one pilot control chamber, controlled by a pilot control valve 2; the main control valve 1 may have one or two working ports. The load pressure of the working port of the main control valve 1 is provided to one side of the movable valve sleeve 21, and the hydraulic pressure of the oil inlet of the main control valve 1 is provided to the other side of the movable valve sleeve 21. Similarly, when the load pressure decreases, the movable valve sleeve 21 in the pilot control valve 2 moves towards closing its internal pilot oil passage, thereby reducing the valve opening of the main control valve 1 and ensuring the stability of the output flow; when the load pressure increases, the movable valve sleeve 21 in the pilot control valve 2 moves towards opening its internal pilot oil passage, thereby increasing the valve opening of the main control valve 1 and ensuring the stability of the output flow.

[0045] Figure 2 This embodiment illustrates one structure of the pilot control valve 2, which includes the aforementioned movable valve sleeve 21, valve sleeve spring 22, and pilot valve core 23. The pilot valve core 23 has a transmission hole 231 for connection to an electromagnet assembly (not shown) on the right side. Under the action of the electromagnet assembly, the pilot valve core 23 can move left or right. The left side of the pilot valve core 23 also abuts against the valve seat 24 via a valve core spring 232. Both the pilot valve core 23 and the valve seat 24 have drain holes 233 connecting to the hydraulic oil tank.

[0046] Furthermore, a drive sleeve 26 is connected to the movable valve sleeve 21 via a limiting pin 25. The drive sleeve 26 is located radially outside the movable valve sleeve 21 and can drive the movable valve sleeve 21 to move together. The pilot control valve 2 also includes a valve body 27. The valve body 27 has a first drive oil passage a and a second drive oil passage b at both ends of the drive sleeve 26. The valve body 27 also has a first drive interface K1 and a second drive interface K2 corresponding to the first drive oil passage a and the second drive oil passage b. The first drive interface K1 and the first drive oil passage a are used to connect to the outlet of the first shuttle valve 3 to the load pressure. The second drive interface K2 and the second drive oil passage b are used to connect to the inlet P of the main control valve 1. When the load pressure changes, causing a change in the pressure difference on both sides of the main control valve 1, the drive sleeve 26 moves left and right, and drives the movable valve sleeve 21 to move left and right. For ease of installation, the valve body 27 can be a split type, for example, including a first valve body 271 and a second valve body 272 on the left, and a third valve body 273 and a fourth valve body 274 on the right, to facilitate the installation of the movable valve sleeve 21, the limit pin 25 and the drive sleeve 26.

[0047] Furthermore, the valve body 27 has an oil inlet passage c at one end of the movable valve sleeve 21, which connects to the oil inlet P' of the pilot control valve 2. The other end of the movable valve sleeve 21 also forms a pressure equalization chamber d. The movable valve sleeve 21 has a pressure equalization damping hole 211 connecting its two ends (shown as a dotted line in the figure, not connected to the oil outlet passage e described below), ensuring that the pilot oil pressure at both ends of the movable valve sleeve 21 is balanced when it moves. The middle part of the movable valve sleeve 21 has an oil outlet passage e connecting to the oil outlet A' of the pilot control valve 2. An oil guide groove 234 is provided on the outer wall of the pilot valve core 23, used to connect and close the oil inlet passage c and the oil outlet passage e when the pilot valve core 23 moves. An inwardly inclined flow channel 235 is formed on the left outer edge of the oil guide groove 234. When the pilot valve core 23 and the movable valve sleeve 21 move towards each other, the communication area between the flow channel 235 and the oil inlet passage c gradually decreases, and the internal pilot oil circuit tends to close more closely; when the pilot valve core 23 and the movable valve sleeve 21 move away from each other, the communication area between the flow channel 235 and the oil inlet passage c gradually increases, and the internal pilot oil circuit tends to connect more closely. Preferably, the fourth valve body 274 has an oil passage f, the inlet area of ​​which is larger than the outlet area of ​​the oil outlet passage e, so that when the movable valve sleeve 21 moves, the oil outlet passage e can be fully connected to the oil passage f.

[0048] The load-sensitive control unit 100 of this embodiment is particularly suitable for load-sensitive systems. In load-sensitive systems, pre-valve compensation or post-valve compensation is generally provided. Combined with the micro-compensation of the movable valve sleeve 21 in this embodiment, the stability of the system output flow is improved.

[0049] Specifically, the load-sensitive control unit in this embodiment further includes a second shuttle valve 41. The first inlet of the second shuttle valve 41 is connected to the load pressure of the working port of the main control valve 1, i.e., connected to the outlet of the first shuttle valve 3. The second inlet of the second shuttle valve 41 is connected to the oil inlet side of the main control valve 1, for example, connected to the oil outlet of the hydraulic compensation valve 5 described below or connected to the oil inlet P of the main control valve 1. The outlet of the second shuttle valve 41 is connected to the load-sensitive interface Ls via a check valve 42. This provides pressure feedback to the load-sensitive control unit 100, and the load-sensing pump (not shown in the figure) in the load-sensitive system can automatically adjust its output pressure according to the maximum load pressure fed back from the system. In this embodiment, the pressure of the oil inlet side of the main control valve 1 is considered during pressure feedback, ensuring that the outlet pressure of the load-sensing pump is the same as the feedback pressure, eliminating redundant pressure and achieving energy saving. Of course, in other embodiments, the outlet of the first shuttle valve 3 can also be directly connected to the load-sensitive interface Ls via the check valve 42. In this case, the outlet pressure of the load-sensing pump needs to be slightly greater than the feedback pressure to compensate for the pressure drop at the valve port of the main control valve 1.

[0050] Furthermore, in this embodiment, the oil inlet P of the main control valve 1 is also provided with a hydraulic compensation valve 5. The oil inlet of the hydraulic compensation valve 5 is used to directly or indirectly connect to the pressure oil output by the load sensing pump, and the oil outlet of the hydraulic compensation valve 5 is directly or via an inlet check valve connected to the oil inlet P of the main control valve 1. The first end of the valve core of the hydraulic compensation valve 5 is provided with a return spring 51, and the first end of the valve core of the hydraulic compensation valve 5 is also connected to the outlet of the first shuttle valve 3 to access the load pressure. The second end of the valve core of the hydraulic compensation valve 5 is connected to the oil outlet of the hydraulic compensation valve 5 via a damper 52. The hydraulic compensation valve 5 can be, but is not limited to, a two-position, two-way valve. Its valve core's left side is acted upon by the return spring 51 and the load pressure, while its right side is acted upon by the oil pressure from the inlet side of the main control valve 1. When the pressure at the outlet of the load-sensing pump increases, the pressure at the outlet of the hydraulic compensation valve 5 gradually increases, causing the force on the right side of its valve core to be greater than that on the left, resulting in a closing tendency. This reduces the inlet pressure of the main control valve 1. Therefore, the increase in system load pressure will not affect the regulating function of the main control valve 1. The pressure difference between the inlet and outlet of the main control valve 1 remains constant, only related to its opening degree, effectively preventing flow control instability caused by changes in system load. In this embodiment, by providing a hydraulic compensation valve 5 at the inlet of the main control valve 1, pressure compensation is achieved, ensuring a constant inlet and outlet pressure difference of the current main control valve 1 and improving the control characteristics of the required flow rate. Together with the aforementioned valve port fine-tuning of the main control valve 1, coordinated compensation control of pressure and valve port compensation is achieved, further improving load response speed and efficiency. In addition, in this embodiment, a damper 52 is provided between the oil outlet of the hydraulic compensation valve 5 and the right end of its valve core to suppress the oscillation caused by inertial or elastic elements, so that the system will not overshoot or become unstable when faced with sudden commands, thus protecting system components and improving stability.

[0051] In this embodiment, the load-sensitive control unit 100 is also provided with an overflow replenishment valve group 6 communicating with the hydraulic oil tank for the first working port A and the second working port B of the main control valve 1, thereby ensuring the overflow replenishment function under special working conditions.

[0052] As can be seen from the above, the load-sensitive control unit provided in this embodiment proposes a pilot-sensitive auxiliary control based on the movement of the pilot control valve sleeve, which ensures the stability of the main control valve flow output when the load fluctuates, and improves the load response speed and efficiency of the system; in addition, together with the pre-valve compensation of the hydraulic compensation valve core, it realizes the coordinated compensation control of valve port and pressure dual compensation.

[0053] Example 2:

[0054] This embodiment provides a load-sensitive valve assembly 200, which includes N load-sensitive control units 100 as described in Embodiment 1, where N is an integer greater than or equal to 2.

[0055] like Figure 3As shown, the load-sensitive valve group 200 includes a flow distribution valve 71 and a priority valve 72. The inlet IN of the flow distribution valve 71 is connected to the outlet of the load-sensing pump. The first outlet OUT1 of the flow distribution valve 71 is connected to the inlet of the priority valve 72. The outlet of the priority valve 72 is connected to one of the load-sensitive control units 100 for oil supply, forming a flow priority loop. The second outlet OUT2 of the flow distribution valve 71 is connected to other load-sensitive control units 100 for oil supply, forming a secondary flow loop.

[0056] The flow distribution valve 71 may be, but is not limited to, a two-position three-way valve, and the priority valve 72 may be, but is not limited to, a two-position two-way solenoid valve. The outlet of the priority valve 72 is also connected to one end of the valve core of the flow distribution valve 71, such as... Figure 3 At the left end, the oil inlet of the priority valve 72 is also connected to the other end of the valve core of the flow distribution valve 71, such as... Figure 3 Right end. When the flow distribution valve 71 is in its initial position, its inlet IN is connected to its first outlet OUT1; when the priority valve 72 is in its initial position, its inlet and outlet are disconnected. When the drive coil of the priority valve 72 is energized, the inlet and outlet of the priority valve 72 are connected, and the forces on both ends of the valve core of the flow distribution valve 71 tend to be balanced. The inlet IN of the flow distribution valve 71 and the first outlet OUT1 remain connected, thus allowing the flow to be preferentially distributed to the first load-sensitive control unit 100. When the drive coil of the priority valve 72 is de-energized, the inlet and outlet of the priority valve 72 are disconnected, and the pressure at the first outlet OUT1 of the flow distribution valve 71 increases, causing the pressure at the right end of its valve core to increase. This causes the flow distribution valve 71 to switch from the left initial position to the right position, and it can be used to supply oil to other load-sensitive control units 100.

[0057] In construction machinery, such as excavators performing combined operations, actions such as boom lifting, stick retraction, and slewing occur. Priority for actions like boom lifting is crucial to ensure operational stability. In this embodiment, the flow distribution valve 71 and priority valve 72 meet the requirements for priority action of the corresponding actuators.

[0058] Preferably, the number N of the load-sensitive control units 100 is an integer greater than or equal to 3. In each load-sensitive control unit 100, the main control valve 1 further includes a first auxiliary oil port U1, a second auxiliary oil port U2, a third auxiliary oil port U3, and a fourth auxiliary oil port U4. The first auxiliary oil port U1 is connected to the oil inlet of each hydraulic compensation valve 5. When the main control valve 1 is in the neutral position, its first auxiliary oil port U1 is connected to the second auxiliary oil port U2, and its third auxiliary oil port U3 is connected to the fourth auxiliary oil port U4. When the main control valve 1 is in the upper or lower position, the first auxiliary oil port U1, the second auxiliary oil port U2, the third auxiliary oil port U3, and the fourth auxiliary oil port U4 are all blocked.

[0059] In the first load-sensitive control unit 100, which corresponds to the actuator that needs to take priority action, for example... Figure 3 The leftmost connection in the middle, wherein the first auxiliary oil port U1 of the main control valve 1 is connected to the oil outlet of the priority valve 72, wherein the fourth auxiliary oil port U4 of the main control valve 1 is connected to the second oil outlet OUT2 of the flow distribution valve 71 via the first auxiliary check valve 81, wherein when the main control valve 1 is in the middle position, its second auxiliary oil port U2 is connected to the third auxiliary oil port U3.

[0060] The second outlet OUT2 of the flow distribution valve 71 is sequentially connected to the first auxiliary port U1 and the second auxiliary port U2 of the main control valve 1 passing through the 2nd to Nth load-sensitive control units 100; when the 2nd to N-1th main control valve 1 are in the neutral position, their second auxiliary port U2 and third auxiliary port U3 are not connected, for example Figure 3 The intermediate connection; when the Nth main control valve 1 is in the neutral position, its second auxiliary oil port U2 is connected to the third auxiliary oil port U3, for example. Figure 3 The rightmost connection in the middle; the fourth auxiliary oil port U4 of the Nth main control valve 1 is connected in reverse order through the third auxiliary oil port U3 and the fourth auxiliary oil port U4 of the N-1 to the 2nd main control valve 1, and the fourth auxiliary oil port U4 of the 2nd main control valve 1 is connected to the oil outlet of the priority valve 72 via the second auxiliary check valve 82.

[0061] Thus, when the first load-sensitive control unit 100 needs to operate first, it can be supplied with oil first; when the main control valve 1 of the first load-sensitive control unit 100 is in the neutral position, the oil can move through the first auxiliary check valve 81 to the main control valve 1 of the second load-sensitive control unit 100; when the main control valve 1 of the second load-sensitive control unit 100 is in the neutral position, the oil can enter the main control valve 1 of the third load-sensitive control unit 100; and so on, to achieve sequential action control. When the first load-sensitive control unit 100 is not operating, the second to Nth load-sensitive control units 100 can also achieve similar sequential action control.

[0062] Furthermore, in the third to Nth load-sensitive control units 100 of this embodiment, at least one first auxiliary port U1 of the main control valve 1 is connected to the second outlet OUT2 of the flow distribution valve 71 via a two-way solenoid valve 73. In its initial position, the inlet and outlet of this two-way solenoid valve 73 are disconnected; when its drive coil is energized, its inlet and outlet are connected. In these third to Nth load-sensitive control units 100, if the first auxiliary port U1 of a certain main control valve 1 is equipped with the two-way solenoid valve 73, when the drive coil of the two-way solenoid valve 73 is energized, the main control valve 1 of this load-sensitive control unit 100 can also operate when the main control valve 1 of the preceding load-sensitive control unit 100 is operating, thus achieving non-sequential active flow distribution.

[0063] like Figure 3 As shown, in one embodiment of this invention, the number of N can be 3, forming a triple valve assembly; in other embodiments of this invention, the number of N can be more than 3, which can be used to form a triple valve assembly. Figure 3 Several load-sensitive control units 100 with the same structure as the second load-sensitive control unit 100 are added between the second and third load-sensitive control units 100 shown. As needed, a two-way solenoid valve 73 can be added between the first auxiliary oil port U1 of these added load-sensitive control units 100 and the second oil outlet OUT2 of the flow distribution valve 71 to achieve active flow control.

[0064] In addition, the load-sensitive valve assembly 200 of this embodiment also includes a load-sensing pump interface Ps for connecting to the outlet of the load-sensing pump; a hydraulic oil tank interface T' for connecting to the hydraulic oil tank; a load pressure interface Pf for taking the load pressure from each load-sensitive control unit 100 and providing it to the load-sensitive interface Ls, which is used to provide feedback on the maximum load pressure; a pilot hydraulic oil depressurization interface cPx, which is connected to the load-sensing pump interface Ps via a pilot depressurization valve 91; and a pilot hydraulic oil pressure interface Px, which is connected to the pilot hydraulic oil depressurization interface cPx via a filter 92. The load-sensitive valve assembly 200 also includes a safety valve assembly 93, with its two ends connected to the load-sensing pump interface Ps and the hydraulic oil tank interface T', respectively, for setting the maximum working safety pressure of the load-sensitive valve assembly 200. The load-sensing pump supplies hydraulic oil to the flow distribution valve 71; the load-sensing pump also supplies hydraulic oil to the pilot control valves 2 of each main control valve 1 via the pilot depressurization valve 91 and the filter 92.

[0065] As can be seen from the above, the load-sensitive valve group provided in this embodiment adopts the load-sensitive control unit described in Embodiment 1, which has the cooperative compensation control of valve port and pressure dual compensation. In addition, it can also realize priority oil supply to specific actuators, as well as sequential and active oil supply to other actuators.

[0066] The above description is only a preferred embodiment of the present utility model, but the protection scope of the present utility model is not limited thereto. Any equivalent substitutions or changes made by those skilled in the art within the technical scope disclosed in the present utility model, based on the technical solution and the inventive concept of the present utility model, should be included within the protection scope of the present utility model.

Claims

1. A load-sensitive control unit, characterized in that, include: The main control valve (1) has a pilot control chamber supplied with hydraulic pressure by the corresponding pilot control valve (2); A pilot control valve (2) includes a movable valve sleeve (21) and a pilot valve core (23). The movable valve sleeve (21) is slidably disposed on the pilot valve core (23). A valve sleeve spring (22) is also provided at one end of the movable valve sleeve (21). The load pressure at the working port of the main control valve (1) can be used to cause the movable valve sleeve (21) of the pilot control valve (2) to move in the direction of connecting the internal pilot oil circuit; the hydraulic pressure at the oil inlet P of the main control valve (1) can be used to cause the movable valve sleeve (21) of the pilot control valve (2) to move in the direction of closing the internal pilot oil circuit.

2. The load-sensitive control unit according to claim 1, characterized in that, The main control valve (1) includes two pilot control chambers, and the pilot control valve (2) corresponds to two; the main control valve (1) includes a first working port A and a second working port B, and the load sensitive control unit also includes a first shuttle valve (3), the first inlet and the second inlet of the first shuttle valve (3) are respectively connected to the first working port A and the second working port B of the main control valve (1), and the hydraulic pressure at the outlet of the first shuttle valve (3) is the load pressure.

3. The load-sensitive control unit according to claim 1, characterized in that, The movable valve sleeve (21) is also connected to a drive sleeve (26) via a limiting pin (25). The drive sleeve (26) is located on the radial outer side of the movable valve sleeve (21). The pilot control valve (2) also includes a valve body (27). The valve body (27) has a first drive oil passage a and a second drive oil passage b at both ends of the drive sleeve (26). The first drive oil passage a is used to connect to the load pressure of the working port of the main control valve (1), and the second drive oil passage b is used to connect to the oil inlet P of the main control valve (1).

4. The load-sensitive control unit according to claim 3, characterized in that, The valve body (27) has an oil inlet passage c at one end of the movable valve sleeve (21) that connects to the oil inlet P' of the pilot control valve (2). The other end of the movable valve sleeve (21) also forms a pressure equalization chamber d. The movable valve sleeve (21) has a pressure equalization damping hole (211) connecting its two ends. The middle part of the movable valve sleeve (21) has an oil outlet passage e that connects to the oil outlet A' of the pilot control valve (2). The outer side wall of the pilot valve core (23) has an oil guide groove (234) for connecting and closing the oil inlet passage c and the oil outlet passage e.

5. The load-sensitive control unit according to any one of claims 1-4, characterized in that, The load-sensitive control unit also includes a second shuttle valve (41). The load pressure of the working port of the main control valve (1) is connected to the first inlet of the second shuttle valve (41). The pressure on the oil inlet side of the main control valve (1) is connected to the second inlet of the second shuttle valve (41). The outlet of the second shuttle valve (41) is connected to the load-sensitive interface Ls via a check valve (42).

6. The load-sensitive control unit according to claim 5, characterized in that, The main control valve (1) is also provided with a hydraulic compensation valve (5) at its oil inlet P. The oil inlet of the hydraulic compensation valve (5) is used to connect to pressurized oil, and the oil outlet of the hydraulic compensation valve (5) is connected to the oil inlet P of the main control valve (1). The first end of the valve core of the hydraulic compensation valve (5) is provided with a return spring (51). The first end of the valve core of the hydraulic compensation valve (5) is also connected to the load pressure of the working port of the main control valve (1). The second end of the valve core of the hydraulic compensation valve (5) is connected to the oil outlet of the hydraulic compensation valve (5) through a damper (52).

7. A load-sensitive valve assembly, characterized in that, It includes N load-sensitive control units as described in claim 6, where N is an integer greater than or equal to 2.

8. The load-sensitive valve assembly according to claim 7, characterized in that, The load-sensitive valve group includes a flow distribution valve (71) and a priority valve (72). The inlet IN of the flow distribution valve (71) is connected to the outlet of the load-sensing pump. The first outlet OUT1 of the flow distribution valve (71) is connected to the inlet of the priority valve (72). The outlet of the priority valve (72) is connected to one of the load-sensitive control units for oil supply. The second outlet OUT2 of the flow distribution valve (71) is connected to other load-sensitive control units for oil supply. The inlet of the priority valve (72) is connected to one end of the valve core of the flow distribution valve (71). The outlet of the priority valve (72) is connected to the other end of the valve core of the flow distribution valve (71). When the flow distribution valve (71) is in the initial position, the inlet IN of the flow distribution valve (71) is connected to the first outlet OUT1.

9. The load-sensitive valve assembly according to claim 8, characterized in that, N is an integer greater than or equal to 3; In each load-sensitive control unit, the main control valve (1) also includes a first auxiliary oil port U1, a second auxiliary oil port U2, a third auxiliary oil port U3 and a fourth auxiliary oil port U4. The first auxiliary oil port U1 is connected to the oil inlet of the hydraulic compensation valve (5). When the main control valve (1) is in the neutral position, its first auxiliary oil port U1 is connected to the second auxiliary oil port U2 and its third auxiliary oil port U3 is connected to the fourth auxiliary oil port U4. In the first load-sensitive control unit, the first auxiliary oil port U1 of the main control valve (1) is connected to the oil outlet of the priority valve (72), and the fourth auxiliary oil port U4 of the main control valve (1) is connected to the second oil outlet OUT2 of the flow distribution valve (71) via the first auxiliary check valve (81). When the main control valve (1) is in the neutral position, its second auxiliary oil port U2 is connected to the third auxiliary oil port U3. The second outlet OUT2 of the flow distribution valve (71) is sequentially connected to the first auxiliary port U1 and the second auxiliary port U2 of the main control valve (1) in the second to Nth load-sensitive control units; when the second to N-1th main control valves (1) are in the neutral position, their second auxiliary port U2 and the third auxiliary port U3 are not connected; when the Nth main control valve (1) is in the neutral position, its second auxiliary port U2 is connected to the third auxiliary port U3; the fourth auxiliary port U4 of the Nth main control valve (1) is sequentially connected to the third auxiliary port U3 and the fourth auxiliary port U4 of the N-1th to 2nd main control valves (1); the fourth auxiliary port U4 of the 2nd main control valve (1) is connected to the outlet of the priority valve (72) via the second auxiliary check valve (82).

10. The load-sensitive valve assembly according to claim 9, characterized in that, In the third to the Nth load-sensitive control units, at least one main control valve (1) has its first auxiliary oil port U1 connected to the second oil outlet OUT2 of the flow distribution valve (71) via a two-way solenoid valve (73).

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