Hydraulic control systems and operating machinery

Abstract

The present application belongs to the field of working machinery, and discloses a hydraulic control system and working machinery. The hydraulic control system is applied to multiple actuators and includes a hydraulic multi-way valve group, including a plurality of valve groups connected in parallel for controlling each of the actuators respectively, each of the valve groups is provided with a valve core control module, and the valve core control module includes a valve core drive motor for driving the reversing valve core of the valve group to move; a controller is electrically connected to each of the valve core drive motors and is used to control the displacement of the reversing valve core. In the present application, each valve group of the hydraulic multi-way valve group is provided with a valve core control module, and the valve core drive motor of the valve core control module can drive the reversing valve core to produce displacement by combining motor drive with mechanical connection transmission to achieve high-precision valve core displacement control, thereby accurately controlling the hydraulic flow distributed to multiple actuators.

Description

Technical Field

[0001] The present application belongs to the field of operating machinery, and specifically, relates to a hydraulic control system and an operating machinery. Background Art

[0002] The hydraulic control systems of excavators and other working machinery usually have hydraulic multi-way valve groups, which are used to control the start, stop and speed control of actuators such as hydraulic cylinders, hydraulic swing and travel motors, as well as to achieve coordination and flexibility of the compound actions of each actuator.

[0003] At present, the conventional control methods for the switch and displacement of the main valve core of the hydraulic multi-way valve group include: hydraulic control, electric proportional direct drive control, electro-hydraulic proportional pressure reducing valve control and other forms. For example, Chinese patent application CN117780707A discloses a hydraulic system, control method, device and operating machinery of a load-sensitive multi-way valve. The hydraulic system adopts an electromagnetic proportional pressure reducing valve to control the hydraulic multi-way valve group. The multi-way valve distributes the flow of the load-sensitive variable pump and supplies it to the actuator of the working device. The two ends of the valve core of the reversing valve are respectively controlled by two electromagnetic proportional pressure reducing valves. The electromagnetic proportional pressure reducing valve is output by the controller to control the output pressure of the electromagnetic proportional pressure reducing valve and the opening of the valve core, thereby controlling the flow from the hydraulic pump to the hydraulic cylinder and the hydraulic motor, and realizing the start and stop and speed control of the action. However, this hydraulic multi-way valve group is mainly driven by hydraulics and electro-hydraulic proportional control, and the displacement of the valve core is driven by establishing a pilot hydraulic pressure. This driving method has the defects of slow hydraulic pressure pressure building speed, resulting in insufficient response, and the pressure fluctuates, resulting in insufficient accuracy and poor stability. At the same time, the displacement of the valve core cannot be detected in real time, and it is difficult to accurately control. Summary of the invention

[0004] The purpose of the present application is to provide a hydraulic control system and an operating machine to achieve high-precision and high-response control of the valve core displacement of a multi-way valve, thereby achieving accurate flow distribution between each valve group.

[0005] To achieve the above-mentioned purpose, the first aspect of the present application provides a hydraulic control system, which is applied to multiple actuators. The hydraulic control system includes:

[0006] A hydraulic multi-way valve group, comprising a plurality of valve groups connected in parallel and used to control the respective actuators, each of which is provided with a valve core control module, and the valve core control module comprises a valve core drive motor for driving the reversing valve core of the valve group to move;

[0007] A controller is electrically connected to each of the valve core drive motors and is used to control the displacement of the reversing valve core.

[0008] In some embodiments, the controller is configured to:

[0009] Driving the valve core driving motor to rotate forward until the first limit end of the valve core stroke, and obtaining a corresponding first motor rotation angle value;

[0010] Driving the valve core drive motor to reverse until it reaches a second limit end of the valve core stroke, and obtaining a corresponding second motor rotation angle value;

[0011] The corresponding valve core drive motor is calibrated at zero position according to the first motor rotation angle value and the second motor rotation angle value.

[0012] In some embodiments, the controller is further configured to:

[0013] Determine that the valve assembly is working properly;

[0014] The valve core drive motor is controlled to reset to a calibrated zero position.

[0015] In some embodiments, the hydraulic control system includes:

[0016] A total oil inlet circuit and a total oil return circuit, wherein the respective oil inlets of the valve groups are connected in parallel to the total oil inlet circuit and the respective oil return ports are connected to the total oil return circuit;

[0017] LS pilot feedback oil circuit, each LS feedback oil port of each valve group is connected to the LS pilot feedback oil circuit;

[0018] An unloading valve, which is hydraulically connected between the main oil inlet circuit and the main oil return circuit and is a normally open valve;

[0019] A first electric proportional pressure reducing valve, electrically connected to the controller, an oil outlet of the first electric proportional pressure reducing valve is connected to the hydraulic control end of the unloading valve, and an oil inlet of the first electric proportional pressure reducing valve is selectively connected to the LS pilot feedback oil circuit or the total oil return oil circuit;

[0020] Wherein, the first electric proportional pressure reducing valve and the valve core control modules of each of the reversing valves are electrically connected to the controller via a CAN bus.

[0021] In some embodiments, the hydraulic control system includes:

[0022] A load-sensitive variable displacement pump, comprising a variable displacement control valve connected to the LS pilot feedback oil circuit;

[0023] A pilot valve group, wherein an oil inlet of the pilot valve group is hydraulically connected to a pumping oil port of the load-sensing variable pump, and an oil outlet of the pilot valve group forms a first pilot control oil circuit connected to the variable control valve;

[0024] The second electric proportional pressure reducing valve is arranged in the first pilot control oil circuit and is used to control the valve core displacement of the variable control valve.

[0025] In some embodiments, the actuator comprises a swing motor, and the hydraulic control system comprises:

[0026] The switch valve, the oil outlet of the pilot valve group also forms a second pilot control oil circuit connected to the motor brake of the rotary motor, and the switch valve is arranged in the second pilot control oil circuit.

[0027] In some embodiments, the controller is configured to:

[0028] Acquire in real time the oil pressure detection value of the oil delivery port of the load-sensitive variable displacement pump and the rotation angle detection value and / or rotation speed detection value of the valve core drive motor;

[0029] Determining that the oil pressure detection value is greater than a preset safety threshold, and the rotation angle detection value and / or the rotation speed detection value are abnormal values;

[0030] The first electric proportional pressure reducing valve is controlled to open the unloading valve to perform an unloading action.

[0031] In some embodiments, the controller is further configured to:

[0032] After the unloading action is performed, the oil pressure detection value of the pumping oil port of the load-sensitive variable pump is obtained again;

[0033] Determining that the oil pressure detection value is still greater than the preset safety threshold;

[0034] The second pilot control oil circuit is controlled so that the load-sensing variable displacement pump operates at a minimum displacement condition.

[0035] In some embodiments, the controller is further configured to:

[0036] After the load-sensitive variable displacement pump operates in a minimum displacement condition, obtaining again a detection value of the oil pressure of the oil delivery port of the load-sensitive variable displacement pump;

[0037] Determining that the oil pressure detection value is still greater than the preset safety threshold;

[0038] The control reduces the speed of the engine driving the load sensing variable displacement pump until the engine stops.

[0039] In some embodiments, the valve core control module includes:

[0040] A centering connection mechanism, axially connected to the end of the reversing valve core;

[0041] The valve core driving motor drives the centering connection mechanism to move linearly;

[0042] The speed reduction mechanism is arranged between the output shaft of the valve core driving motor and the centering connection mechanism.

[0043] A second aspect of the present application provides a working machine, which includes the above-mentioned hydraulic control system.

[0044] In the operating machinery and its hydraulic control system of the present application, each valve group of the hydraulic multi-way valve group is provided with a valve core control module. The valve core drive motor of the valve core control module can drive the reversing valve core of the valve group to move with high precision and high responsiveness, that is, the controller can control the rotation of the motor, thereby driving the reversing valve core to produce displacement by combining motor drive with mechanical connection transmission, thereby realizing high-precision valve core displacement control, thereby facilitating precise control of the hydraulic flow distributed to multiple actuators.

[0045] Other advantages of the present invention and the technical effects of the preferred embodiments will be further described in the following specific embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] The accompanying drawings are used to provide an understanding of the present application and constitute a part of the specification. Together with the following specific embodiments, they are used to explain the present application but do not constitute a limitation to the present application. In the accompanying drawings:

[0047] Figure 1 It is a hydraulic principle diagram of a hydraulic control system according to a specific embodiment of the present application, which shows the composition of a hydraulic multi-way valve group;

[0048] Figure 2 for Figure 1 The first part of

[0049] Figure 3 for Figure 1 The second part of

[0050] Figure 4 for Figure 1 The hydraulic principle diagram of the Nth valve group in the hydraulic multi-way valve group shown in the figure, wherein the valve core control module is illustrated;

[0051] Figure 5 Picture shows Figure 4 The specific structure of the reversing valve in the Nth valve group shown;

[0052] Figure 6 for Figure 4 The structural schematic diagram of the valve core control module shown;

[0053] Figure 7 A hydraulic multi-way valve of a hydraulic control system according to one of other embodiments of the present application is illustrated;

[0054] Figure 8 for Figure 7 The first part of

[0055] Fig. 9 for Figure 7 The second part of

[0056] Fig.10 A hydraulic multi-way valve of a hydraulic control system according to another embodiment of the present application is illustrated;

[0057] Fig.11 for Fig.10 The first part of

[0058] Fig.12 for Fig.10 The second part of

[0059] Fig.13 The structural layout of the valve core control module on the valve body in a certain implementation mode is shown;

[0060] Fig.14 The structural layout of the valve core control module on the valve body in another embodiment is shown;

[0061] Fig.15 The structural layout of the valve core control module on the valve body in another embodiment is shown;

[0062] Fig.16 A hydraulic principle diagram of a hydraulic control system according to another embodiment of the present application;

[0063] Fig.17 for Fig.16 A partial enlarged schematic diagram of a hydraulic pump control portion of the hydraulic control system shown;

[0064] Fig.18 for Fig.16 A partial enlarged schematic diagram of a multi-way valve control portion of a hydraulic control system shown;

[0065] Fig.19 for Fig.18 The first part of

[0066] Fig. 20 for Fig.18 The second part of

[0067] Fig.21 A flow chart for performing a zero calibration procedure for a controller;

[0068] Fig. 22 Flowchart for executing a safety pressure protection procedure for a controller. DETAILED DESCRIPTION

[0069] The specific embodiments of the present invention are described in detail below in conjunction with the accompanying drawings. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present invention and are not intended to limit the present invention. It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other.

[0070] The present invention will be described in detail below with reference to the accompanying drawings and in combination with embodiments.

[0071] See also Figures 1 to 5 In a specific embodiment of the present application, a new type of reversing valve is disclosed, and the reversing valve includes:

[0072] The valve body comprises a valve core cavity and a reversing valve core 13 slidably arranged in the valve core cavity;

[0073] The valve core control module 50 is used to drive the reversing valve core 13 to move axially in the valve core cavity and includes a valve core drive motor 23 and a centering connection mechanism 15 for realizing axial connection transmission between the valve core drive motor 23 and the reversing valve core 13 .

[0074] The present application aims to achieve high-precision control and rapid responsiveness of the valve opening of the reversing valve, and for this purpose, the traditional pilot hydraulic control method or electro-hydraulic control method is abandoned, and a mechanical drive method of a motor-driven valve core is adopted. Figure 4 , a valve core control module 50 with a centering connection mechanism 15 is added, and the valve core control module 50 can be installed at the end of the valve body to connect and drive the reversing valve core 13. The reversing valve core 13 is driven by a motor, and the control time is strong and the response is fast. The centering connection mechanism 15 is set on the transmission path driven by the motor, which can avoid the problems of valve core eccentricity and jamming caused by machining errors or rigid connection transmission, and is conducive to the smooth displacement of the valve core and its accurate detection and control.

[0075] It is well known to those skilled in the art that in the existing hydraulic multi-way valve group, the conventional control methods for the switch and displacement of the main valve core of the reversing valve generally include hydraulic control, electric proportional direct drive control, electro-hydraulic proportional pressure reducing valve control and other forms. The use of an electric proportional valve direct drive valve core can achieve rapid reversal and displacement retention, and good linearity, but there is a disadvantage of insufficient driving force. If the flow rate of the main valve core is large and the pressure is high, the hydraulic force and disturbance of the electric proportional direct drive are large, which can easily lead to system instability and excessive volume of the solenoid valve block. The electro-hydraulic proportional pressure reducing valve controls the current size by the controller to achieve switching and linear opening. The switching and linear opening of the electric proportional pressure reducing valve realize the control of the pressure size of the pilot oil source (i.e., secondary pressure). The secondary pressure acts on the main valve core to realize the control of the switching and linear displacement of the main valve core. This control method has the advantages of low hardware cost and mature technology, but also has the disadvantages of not responding quickly enough because it takes time to build up the hydraulic pressure; the inconsistency caused by the difference in the processing and manufacturing of the electric proportional valve affects the accuracy of the current-secondary pressure output, the hysteresis loop accuracy is not high enough, and the overall control characteristics are affected.

[0076] Comparatively, the present application adopts a valve core control module 50 with a valve core drive motor 23, and utilizes its mechanical connection transmission structure, without hydraulic buffering, and has a faster response. The motor drive torque is larger, and smooth loading and precise control of speed can be achieved, without overshoot of hydraulic pressure, and the control is more stable and smooth.

[0077] The valve core control module 50 may further include a speed reduction mechanism 14 disposed between the output shaft of the valve core drive motor 23 and the centering connection mechanism 15. The speed reduction mechanism 14 may be disposed separately outside the motor or integrated at the output end of the motor, and its main function is to reduce speed and increase torque, and convert the rotary motion of the rotary motor into a linear displacement motion. That is, the speed reduction mechanism 14 is conducive to converting high speed to low speed and increasing torque and driving force.

[0078] See also Figure 6 The speed reduction mechanism 14 of this embodiment may include a gear rack transmission structure, a transmission gear 141 of the gear rack transmission structure is installed at the output end of the motor shaft, and a spur rack 142 of the gear rack transmission structure may be coaxially arranged with the reversing valve core 13, so that the motor rotational motion can be converted into the axial displacement of the valve core. It can be understood by those skilled in the art that the speed reduction mechanism 14 is not limited to the gear rack transmission structure shown in the figure, and may also adopt many other structural forms, such as a worm gear, a ball screw, etc.

[0079] The centering connection mechanism 15 is used for coaxial transmission without jamming between the output shaft (or reduction mechanism 14) of the valve core drive motor 23 and the reversing valve core 13. Therefore, the centering connection mechanism 15 is connected to the end of the reversing valve core 13 or the reduction mechanism 14 and is roughly axially aligned to ensure that there is no jamming obstruction in the axial movement of the valve core. The centering connection mechanism 15 can be a rigid connection mechanism or a flexible connection mechanism. The rigid connection mechanism can be made of high-precision metal materials to achieve accurate axial alignment and transmission between the motor and the valve core. The centering connection mechanism 15 can also adopt a flexible connection mechanism, thereby reducing the accuracy requirements for axial alignment, but can also achieve unobstructed axial connection transmission. The flexible connection mechanism may include, for example, springs, non-metallic parts, etc.

[0080] As an example, the centering connection mechanism 15 in this embodiment includes a plunger, a flexible connecting rod and / or a rigid connecting rod. Figure 6 As shown, the spur rack, plunger and reversing valve core 13 ( Figure 6 The piston cavity has a guiding and regulating function for the linear movement of the piston, and can guide the slight linear deviation of the straight rack, so as not to guide the driving force of the deviation to the valve core and cause problems such as eccentricity and sticking. Furthermore, one rod end of the piston connected to the valve core and / or the other rod end of the piston connected to the straight rack can be a flexible connecting rod, which can further reduce the influence of the slight linear deviation of the straight rack on the eccentric transmission of the reversing valve core 13. It should be noted that the centering connection mechanism 15 is not limited to the piston here, and can also be an elastic strip or a spring member, a metal plunger as a rigid connection mechanism, and the like.

[0081] In this embodiment, in order to prevent the leaked oil from being blocked at both ends of the valve core, the ends of the valve core cavity are connected to the valve core oil return oil circuit, for example Figure 1 , Figure 2 , Figure 3 As shown in the figure, the first valve core oil return circuit 19 and the second valve core oil return circuit 21. Therefore, the oil leakage of the valve cavity of the reversing valve can be returned to the hydraulic oil tank 3 through the oil return circuit at the end, so as to avoid the leaked oil blocking the two ends of the valve core, which becomes an obstacle to the movement of the reversing valve core 13 and also affects the accurate detection and control of the valve core stroke. Of course, the valve core oil return circuit can also be set at only one end of the valve cavity of the reversing valve, and the valve cavity end of the reversing valve is generally provided with a return spring 18.

[0082] The valve core drive motor 23 can be of a size that matches the valve body connected to the valve group. In this embodiment, the valve core drive motor 23 is a micro servo motor that can rotate forward and reverse, and the micro servo motor includes an angle detection feedback unit and a speed detection feedback unit. The servo motor can accurately control the rotation angle and speed, and further has detection and feedback functions such as forward / reverse rotation, angle speed and torque. Under the control of the controller 100, closed-loop feedback of the displacement value and speed value of the reversing valve core 13 can be achieved, and fast, accurate and high-response control can be achieved, which will be explained in detail below.

[0083] See also Figure 1 , Figure 2 , Figure 3 The valve core control module 50 can be installed as a separate module at the end of the valve body. Further, in this embodiment, the valve core control module 50 can be detachably installed at the end of the valve body. This modular and detachable design is convenient for installation and wiring operations. Figures 13 to 15 In the Nth valve group 12, the valve core control module 50 can be detachably installed at any end of the valve body. In actual operation, the valve core control module 50 can be used as a replacement for the end cover of the valve body, installed at the end of the valve body with the screw holes aligned, and connected to the CAN bus 16 through the control end interface 30.

[0084] Based on the above-mentioned reversing valve, the present application also discloses a new type of hydraulic multi-way valve group 5, including a plurality of valve groups arranged in parallel, the valve group including the above-mentioned reversing valve. Figure 1 , Figure 7 , Fig.10 As shown, as an example, the hydraulic multi-way valve group 5 includes a first valve group 6, a second valve group 7, a third valve group 8, a fourth valve group 9, a fifth valve group 10, a sixth valve group 11 and an Nth valve group 12, where N can be any integer greater than six.

[0085] Each valve group controls at least one corresponding actuator. To facilitate control, the hydraulic multi-way valve group 5 can have a CAN bus communication function, see Figures 7 to 9 , Figures 10 to 12 , Figures 16 to 20 The first electric proportional pressure reducing valve 2 and each valve core control module 50 can be electrically connected to the controller 100 through the CAN bus 16. When each valve core control module 50 is arranged on the same side of the hydraulic multi-way valve group 5, it is beneficial to the wiring of the CAN bus 16. Figures 7 to 9 It can be seen that each valve core control module 50 can be arranged on any side of the hydraulic multi-way valve group 5 or can also be distributed on both sides of the valve body.

[0086] Specifically, see Figures 13 to 15The valve group can be arranged along the valve width direction of the hydraulic multi-way valve group 5 (i.e., the horizontal direction of the paper shown in the figure), and several valve groups are stacked in sequence along the valve length direction of the hydraulic multi-way valve group 5 (i.e., the vertical direction of the paper shown in the figure); wherein the valve core control modules 50 of each reversing valve are arranged on the same side of the valve width direction of the hydraulic multi-way valve group 5, such as Fig.14 , Fig.15 Alternatively, each valve core control module 50 is disposed on both sides of the valve width direction of the hydraulic multi-way valve group 5 and is staggered in sequence along the valve length direction, such as Fig.13 shown.

[0087] See also Figure 1 , Fig.16 , the respective oil inlets of the plurality of valve groups are connected in parallel to the total oil inlet oil circuit 27 and the respective oil return ports are connected to the total oil return oil circuit 22, and the LS feedback oil ports of the plurality of valve groups are connected to the LS pilot feedback oil circuit 26; wherein the hydraulic multi-way valve group 5 may also include:

[0088] The unloading valve 1 is hydraulically connected between the main oil inlet circuit 27 and the main oil return circuit 22 and is a normally open valve;

[0089] The first electric proportional pressure reducing valve 2 , the oil outlet of the first electric proportional pressure reducing valve 2 is connected to the hydraulic control end of the unloading valve 1 , and the oil inlet of the first electric proportional pressure reducing valve 2 is selectively connected to the LS pilot feedback oil circuit 26 or the total return oil circuit 22 .

[0090] Among them, the function of the unloading valve 1 is to relieve pressure, especially when the actuator is not working or is shut down in an emergency and the main pump is just started, the pumped hydraulic oil of the main pump can be returned to the hydraulic oil tank 3 in time through the unloading valve 1 to avoid excessive pressure at the oil inlet of the reversing valve and disturbance of the valve core displacement. The unloading valve 1 is a normal conduction valve, that is, it is in a normally open state. In this way, when the main pump is just started, the pumped hydraulic oil in the total oil inlet oil circuit 27 can be returned in time through the unloading valve 1 and the total oil return oil circuit 22, without affecting the reversing operation of the reversing valve, that is, without affecting the movement of the valve core driven by the motor.

[0091] The unloading valve 1 is pilot-controlled by the first electric proportional pressure reducing valve 2. Under the control of the end electromagnet by the controller 100, the oil inlet of the first electric proportional pressure reducing valve 2 can be selectively connected to the LS pilot feedback oil circuit 26 or the total oil return oil circuit 22. Figure 1In the embodiment, when the electromagnet of the first electric proportional pressure reducing valve 2 is not energized, the oil inlet of the first electric proportional pressure reducing valve 2 is connected to the LS pilot feedback oil circuit 26. When the main pump is just started, the LS pilot feedback oil circuit 26 is low-pressure oil, and the unloading valve 1 remains in the on position. When the actuator is working normally, the LS pilot feedback oil circuit 26 is high-pressure oil, and the high-pressure oil will act on the hydraulic control end of the unloading valve 1 through the first electric proportional pressure reducing valve 2 to close the unloading valve 1, so that the main pump hydraulic oil fully acts on the actuator. When it is necessary to control the unloading of the unloading valve 1, it is only necessary to energize the electromagnet of the unloading valve 1 so that the hydraulic control end of the unloading valve 1 is hydraulically connected to the main return oil circuit 22 through the first electric proportional pressure reducing valve 2, and the unloading valve 1 is switched to the on position to achieve unloading.

[0092] It can be seen that the unloading valve 1 is controlled by the first electric proportional pressure reducing valve 2 so that the normal position of the unloading valve 1 is in the conducting position, which can avoid the oil cannot return to the oil tank when starting or the main valve core is stuck, and the main oil circuit cannot return to the oil tank, resulting in high oil circuit pressure or dangerous situations. In addition, the relief valve 4 is arranged between the LS pilot feedback oil circuit 26 and the total return oil circuit 22, so that when the oil pressure of the LS pilot feedback oil circuit 26 is too high, the pressure can be relieved through the relief valve 4 to avoid impact on the variable control valve of the variable pump.

[0093] The hydraulic multi-way valve group 5 can be applied to various types of operating machinery, such as excavators, etc. When controlling the flow distribution of multiple actuators, its working principle is:

[0094] The CAN bus 16 receives the control signal sent by the controller 100, and can control the valve core drive motor 23 of each valve group respectively, so that the valve core drive motor 23 rotates forward / reverse, and the motor's rotation angle and speed are fed back to the CAN bus 16; when the valve core drive motor 23 rotates forward / reverse, it drives the reduction mechanism 14 to reduce speed and increase torque and rotate forward / reverse, and the reduction mechanism 14 drives the reversing valve core 13 to perform a linear sliding displacement in the valve body through the centering connection mechanism 15; the leakage oil between the reversing valve core 13 and the valve body is returned to the hydraulic oil tank 3 through the first valve core return oil circuit 19 and the second valve core return oil circuit 21. The displacement of the reversing valve core 13 can be converted through the relationship between the valve core drive motor 23 and the reduction mechanism 14 through the centering connection mechanism 15, so as to realize the closed-loop feedback of the conversion speed and displacement of the reversing valve core 13 by the drive motor speed and rotation angle. Among them, it satisfies:

[0095] V f =K1V t , S f =K2θ t

[0096] V f is the valve core displacement speed value, V t is the speed value of the driving motor, K1 is the speed conversion coefficient, S fis the valve core displacement value, θ t is the rotation angle of the driving motor, and K2 is the displacement conversion coefficient.

[0097] At the same time, when the valve core driving motor 23 drives the reversing valve core 13 to perform displacement reversal in forward / reverse rotation, the reversal of the reversing valve core 13 causes the large / small chamber of the hydraulic cylinder 25 serving as the actuator to connect to the Pp and Ts ports respectively, thereby realizing the operation of the hydraulic cylinder 25.

[0098] When the first electric proportional pressure reducing valve 2 is energized, the pressure in the LS pilot feedback oil circuit 26 causes the unloading valve 1 to reach the cut-off position; when the first electric proportional pressure reducing valve 2 is de-energized, the pressure in the LS pilot feedback oil circuit 26 causes the unloading valve 1 to reach the conduction position, thereby realizing the oil return in the total oil inlet circuit 27 and achieving unloading.

[0099] In summary, the hydraulic multi-way valve group 5 of the present application can realize closed-loop feedback of motor speed, angle and torque by adding a modular valve core control module 50 and adding the application of a motor, so as to realize accurate detection of valve core displacement; the motor drive torque can realize smooth loading and accurate control of speed, there is no overshoot of hydraulic pressure, and the control is more stable and smooth; the motor drive is through mechanical transmission, rigid and flexible mechanical structure connection, there is no hydraulic buffer, and the response is faster.

[0100] In addition, the present application also discloses a hydraulic control system, which is applied to multiple actuators, such as the rotary motor 24 and the hydraulic cylinder 25 shown in the figure. Fig.16 As shown, in a specific embodiment, the hydraulic control system includes:

[0101] The hydraulic multi-way valve group 5 includes a plurality of valve groups connected in parallel and used to control the respective actuators respectively, each valve group is provided with a valve core control module 50, and the valve core control module 50 includes a valve core drive motor 23 for driving the reversing valve core 13 of the valve group to move;

[0102] The controller 100 is electrically connected to each valve core driving motor 23 and is used to control the displacement of the reversing valve core 13 .

[0103] The hydraulic control system of the present application adopts the above-mentioned hydraulic multi-way valve group 5, that is, each valve group is provided with a valve core control module 50, and the valve core control module 50 may include a valve core drive motor 23 for driving the reversing valve core 13 of the valve group to move, that is, the controller 100 can control the motor to drive the reversing valve core 13 with a mechanical connection, so as to achieve high-response and high-precision valve core displacement control, thereby facilitating the control of flow distribution between multiple actuators.

[0104] In this embodiment, in terms of hardware improvement, the valve core control module 50 may include:

[0105] A centering connection mechanism 15 is axially connected to the end of the reversing valve core 13;

[0106] The valve core driving motor 23 drives the centering connection mechanism 15 to move linearly;

[0107] The speed reduction mechanism 14 is disposed between the output shaft of the valve core driving motor 23 and the centering connection mechanism 15 .

[0108] The function of the speed reduction mechanism 14 is to reduce speed and increase torque and convert the rotary motion of the rotary motor into a linear displacement motion. The centering connection mechanism 15 is arranged on the transmission path driven by the motor, which can avoid problems such as valve core eccentricity and jamming caused by machining errors or rigid connection transmission, and is conducive to the smooth displacement of the valve core and its accurate detection and control, and finally realizes accurate flow control of each actuator.

[0109] For communication control, see Fig.16 , the CAN bus 16 is connected to the electrical harness of the controller 100, so as to realize the fast and timely two-way transmission and communication of data between the controller 100 and the valve core control module 50. The CAN bus 16 receives the control signal sent by the controller 100, and can control the valve core drive motor 23 of each valve group respectively, so that the valve core drive motor 23 rotates forward / reverse, and feeds back the rotation angle and speed of the motor to the CAN bus 16; when the valve core drive motor 23 rotates forward / reverse, it drives the speed reduction mechanism 14 to reduce speed and increase torque and rotate forward / reverse, and the speed reduction mechanism 14 drives the reversing valve core 13 to slide linearly in the valve body through the centering connection mechanism 15.

[0110] See also Fig.13 , the controller 100 is configured as:

[0111] The valve core driving motor 23 is driven to rotate forward until it reaches a first limit end of the valve core stroke, and a corresponding first motor rotation angle value is obtained;

[0112] The valve core driving motor 23 is driven to reversely rotate until the second limit end of the valve core stroke, and the corresponding second motor rotation angle value is obtained;

[0113] According to the first motor rotation angle value and the second motor rotation angle value, the corresponding valve core drive motor 23 is calibrated to zero position.

[0114] In the hydraulic control system of the present application, the valve core control module 50 needs to be zero-position calibrated before being activated, that is, the controller 100 needs to have a zero-position calibration function, so that the motor angle is associated with the valve core stroke and the angle starting position and the valve core stroke middle position, which is the so-called zero position, are determined. Therefore, before starting, it is necessary to first drive the motor forward and forward to the valve core stroke limit point at one end, record the motor angle value at that time, and then drive the motor reverse and reverse to the valve core stroke limit point at the other end, and also record the motor angle value at this time. According to the following formula, that is:

[0115] V f =K1V t , S f =K2θ t

[0116] Among them, V f is the valve core displacement speed value, V t is the speed value of the driving motor, K1 is the speed conversion coefficient, S f is the valve core displacement value, θ t is the rotation angle of the driving motor, and K2 is the displacement conversion coefficient.

[0117] It can be seen that the rotation angle value is roughly linearly proportional to the valve core displacement value, and the rotation speed is the same as the displacement speed. In this way, the motor zero position, that is, the motor rotation angle starting position, can be calculated through the above-mentioned first motor rotation angle value and second motor rotation angle value, so that the zero position calibration can be performed.

[0118] Furthermore, the controller 100 may also be configured as:

[0119] Make sure the valve assembly works normally;

[0120] The control valve core drive motor 23 is reset to the calibrated zero position.

[0121] See also Fig.21 The zero position calibration procedure of the controller 100 also has a determination step, such as determining whether the valve core stroke range is within a preset range, whether the motor angle range is within a preset range, etc. If there is any discrepancy, there may be a component failure or other problems that need to be eliminated. After eliminating them, zero position calibration is performed again. After zero position calibration, reset is performed, and then the controller 100 can accurately control the motor and valve core.

[0122] See also Fig.16 , Fig.18 , the hydraulic control system also includes:

[0123] The main oil inlet circuit 27 and the main oil return circuit 22, the respective oil inlets of the valve groups are connected in parallel to the main oil inlet circuit 27 and the respective oil return ports are connected to the main oil return circuit 22;

[0124] LS pilot feedback oil circuit 26, the respective LS feedback oil ports of each valve group are connected to the LS pilot feedback oil circuit 26;

[0125] The unloading valve 1 is hydraulically connected between the main oil inlet circuit 27 and the main oil return circuit 22 and is a normally open valve;

[0126] The first electric proportional pressure reducing valve 2 is electrically connected to the controller 100 , the oil outlet of the first electric proportional pressure reducing valve 2 is connected to the hydraulic control end of the unloading valve 1 , and the oil inlet of the first electric proportional pressure reducing valve 2 is selectively connected to the LS pilot feedback oil circuit 26 or the total return oil circuit 22 .

[0127] Based on the first electric proportional pressure reducing valve 2 and the unloading valve 1, the controller 100 may also have an unloading control function, that is, the unloading function of the unloading valve 1 is controlled to be opened or closed by controlling the first electric proportional pressure reducing valve 2, which will be explained in detail below.

[0128] See also Fig.16 , Fig.17 , the hydraulic control system may include:

[0129] A load-sensing variable displacement pump 31, including a variable displacement control valve 35 connected to the LS pilot feedback oil circuit 26;

[0130] A pilot valve group 40, an oil inlet of the pilot valve group 40 is hydraulically connected to a pumping oil port of a load-sensing variable pump 31, and an oil outlet of the pilot valve group 40 forms a first pilot control oil circuit 41 connected to a variable control valve 35;

[0131] The second electric proportional pressure reducing valve 32 is disposed in the first pilot control oil circuit 41 and is used to control the valve core displacement of the variable control valve 35 .

[0132] The hydraulic control system in this embodiment adopts a load-sensitive variable pump 31, and the LS feedback oil port of each valve group is hydraulically connected to the variable control valve 35 through the LS pilot feedback oil circuit 26 to feedback and control the displacement of the variable pump. It should be noted that the composition of the load-sensitive variable pump 31 and its variable control valve 35, and the connection and feedback control method of the variable control valve 35 and the LS pilot feedback oil circuit 26 are well known to those skilled in the art, and will not be described in detail here.

[0133] In this embodiment, a second electric proportional pressure reducing valve 32 is specially provided to introduce the pilot oil in the first pilot control oil circuit 41 of the pilot valve group 40 into the control chamber of the variable control valve 35, which is also used to ultimately control the displacement of the variable pump. However, it should be noted that the priority of the pilot oil in the first pilot control oil circuit 41 is higher than the pilot oil in the LS pilot feedback oil circuit 26. In other words, under the control of the second electric proportional pressure reducing valve 32, the pilot oil in the first pilot control oil circuit 41 acts on the variable control valve 35 first, and actively intervenes in the displacement of the variable pump.

[0134] like Fig.17 As shown, the pilot valve group 40 reduces the pressure of the pumping oil of the variable pump and outputs it to the first pilot control oil circuit 41 and acts on the plunger 34 through the outlet of the second electric proportional pressure reducing valve 32. The plunger 34 is mechanically connected and pushes the valve core of the variable control valve 35 to produce a displacement change. The valve core of the variable control valve 35 is mechanically connected to the displacement plunger 36 to act on the displacement adjustment of the variable pump.

[0135] Also, see Fig.16 , Fig.18 , the plurality of actuators may include a rotary motor 24, a hydraulic cylinder 25, etc., and the hydraulic control system may also include:

[0136] The switch valve 43 , the oil outlet of the pilot valve group 40 also forms a second pilot control oil path 42 connected to the motor brake of the swing motor 24 , and the switch valve is arranged in the second pilot control oil path 42 .

[0137] The second pilot control oil circuit 42 and the first pilot control oil circuit 41 are parallel oil circuits at the outlet of the pilot valve group 40. The pilot oil of the second pilot control oil circuit 42 is used to open the motor brake of the swing motor 24 to release the motor brake. The switch valve 43 is used to control the on and off of the second pilot control oil circuit 42. When the switch valve 43 is in the on state, the pilot oil of the second pilot control oil circuit 42 acts on the motor brake through the delay valve 28 to release the motor brake, and the swing motor 24 can be driven to rotate by the pressure oil.

[0138] See also Fig. 22 ,exist Fig.16 Based on the hydraulic control system shown, the controller 100 may be configured as follows:

[0139] Real-time acquisition of the oil pressure detection value of the oil delivery port of the load-sensitive variable displacement pump 31 and the rotation angle detection value and / or rotation speed detection value of the valve core drive motor 23;

[0140] Determining that the oil pressure detection value is greater than a preset safety threshold, and the rotation angle detection value and / or the rotation speed detection value are abnormal values;

[0141] The first electric proportional pressure reducing valve 2 is controlled to turn on the unloading valve 1 to perform the unloading action.

[0142] It can be seen that the controller 100 can have a safety pressure protection function. Fig. 22In the flowchart of the safety pressure protection program shown, when the system is started, the controller 100 can obtain the oil pressure detection value of the pumping oil port of the load-sensitive variable pump 31 in real time through the oil pressure detection element 33, and can realize two-way data transmission and communication with the valve core control module 50 through the CAN bus 16. Once it is determined that the oil pressure detection value is greater than the preset safety threshold, that is, the outlet pressure value of the variable pump is outside the preset safety threshold, and the angle detection value and / or the speed detection value are abnormal values, it means that the detection feedback of the valve core drive motor 23 is abnormal, and fault diagnosis can be performed. Further, the unloading valve 1 can be controlled to perform unloading through the first electric proportional pressure reducing valve 2. At this time, the electromagnet of the first electric proportional pressure reducing valve 2 can be controlled to be energized, and the oil inlet of the first electric proportional pressure reducing valve 2 is connected to the return oil circuit, so that the unloading valve 1 is switched to the conduction position, and the unloading valve 1 performs the unloading action.

[0143] Furthermore, the controller 100 may be configured as follows:

[0144] After the unloading action is performed, the oil pressure detection value of the pumping oil port of the load-sensing variable pump 31 is obtained again;

[0145] Determine that the oil pressure detection value is still greater than the preset safety threshold;

[0146] The second electric proportional pressure reducing valve 32 is controlled so that the load-sensing variable displacement pump 31 operates at the minimum displacement condition.

[0147] It can be seen that after the variable pump and the valve core drive motor have abnormalities and perform unloading actions, it is necessary to detect and judge again. If it is determined that the oil pressure detection value is still greater than the preset safety threshold, it means that there is unloading or other faults, and further displacement control is required. That is, by controlling the second electric proportional pressure reducing valve 32, the load-sensitive variable pump 31 works at the minimum displacement condition. In other words, it is necessary to actively intervene in the displacement of the variable pump in time to reduce the displacement of the variable pump as soon as possible to avoid pressure holding, impact, etc., which may cause damage to the system, oil circuit and valve components.

[0148] Furthermore, the controller 100 may be further configured as:

[0149] After the load-sensing variable displacement pump 31 operates at the minimum displacement condition, the oil pressure detection value of the oil delivery port of the load-sensing variable displacement pump 31 is obtained again;

[0150] Determine that the oil pressure detection value is still greater than the preset safety threshold;

[0151] The control reduces the rotation speed of the engine for driving the load sensing variable displacement pump 31 until the engine stops.

[0152] After actively intervening in the displacement of the variable pump and the displacement of the variable pump reaches the minimum, it is necessary to detect and judge again. If it is determined that the oil pressure detection value is still greater than the preset safety threshold, it is necessary to finally perform engine control on the engine driving the load-sensitive variable pump 31, and gradually reduce the engine speed until it stops working and the engine is turned off, so as to ultimately ensure system safety.

[0153] When the hydraulic control system of the present application is used in working machinery such as excavators, it can realize precise control of the valve core displacement of the reversing valve, unload the variable pump when it starts and when the valve core is stuck, and avoid the occurrence of safety accidents. The working machinery is not limited to excavators, but can also be loaders, bulldozers, etc. Among them, for the control of the reversing valve core connected to the valve group in the hydraulic multi-way valve group, it has a "drive motor + deceleration" drive control method and a CAN bus communication method. The hydraulic multi-way valve group, the load-sensitive variable pump, the electric proportional pressure reducing valve, the unloading valve, etc. constitute a hydraulic circuit and system; the controller has a zero-position calibration function and a safety pressure protection function.

[0154] In the description of the present application, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of the present application, "plurality" means at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0155] In this application, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, an electrical connection, or communication with each other; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0156] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0157] Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limitations on the present application. Ordinary technicians in this field can change, modify, replace and modify the above embodiments within the scope of the present application.

Claims

1. Hydraulic control system, applied to multiple actuators, characterized in that: The hydraulic control system comprises: A hydraulic multi-way valve group (5), comprising a plurality of valve groups connected in parallel and used to control the respective actuators, each of the valve groups being provided with a valve core control module (50), the valve core control module (50) comprising a valve core drive motor (23) used to drive the reversing valve core (13) of the valve group to move; A controller (100) electrically connected to each of the valve core drive motors (23) and used to control the displacement of the reversing valve core (13); A total oil inlet circuit (27) and a total oil return circuit (22), wherein the respective oil inlets of the valve groups are connected in parallel to the total oil inlet circuit (27) and the respective oil return ports are connected to the total oil return circuit (22); LS pilot feedback oil circuit (26), wherein the respective LS feedback oil ports of the respective valve groups are connected to the LS pilot feedback oil circuit (26); A load-sensitive variable displacement pump (31) comprising a variable displacement control valve (35) connected to the LS pilot feedback oil circuit (26); A pilot valve group (40), wherein an oil inlet of the pilot valve group (40) is hydraulically connected to an oil pumping port of the load-sensing variable pump (31), and an oil outlet of the pilot valve group (40) forms a first pilot control oil circuit (41) connected to the variable control valve (35); A second electric proportional pressure reducing valve (32) is arranged in the first pilot control oil circuit (41) and is used to control the valve core displacement of the variable control valve (35).

2. The hydraulic control system according to claim 1, characterized in that: The controller (100) is configured to: Driving the valve core drive motor (23) to rotate forward until reaching a first limit end of the valve core stroke, and obtaining a corresponding first motor rotation angle value; Driving the valve core drive motor (23) to rotate in reverse until reaching a second limit end of the valve core stroke, and obtaining a corresponding second motor rotation angle value; According to the first motor rotation angle value and the second motor rotation angle value, the corresponding valve core drive motor (23) is calibrated at zero position.

3. The hydraulic control system according to claim 2, characterized in that: The controller (100) is also configured to: Determine that the valve assembly is working properly; The valve core drive motor (23) is controlled to reset to a calibrated zero position.

4. The hydraulic control system according to any one of claims 1 to 3, characterized in that: The hydraulic control system comprises: An unloading valve (1) is hydraulically connected between the main oil inlet circuit (27) and the main oil return circuit (22) and is a normally open valve; a first electric proportional pressure reducing valve (2), electrically connected to the controller (100), an oil outlet of the first electric proportional pressure reducing valve (2) connected to the hydraulic control end of the unloading valve (1), and an oil inlet of the first electric proportional pressure reducing valve (2) selectively connected to the LS pilot feedback oil circuit (26) or the total oil return oil circuit (22); The first electric proportional pressure reducing valve (2) and the valve core control modules (50) of each of the reversing valves are electrically connected to the controller (100) via a CAN bus (16).

5. The hydraulic control system according to any one of claims 1 to 3, characterized in that: The actuator comprises a rotary motor (24), and the hydraulic control system comprises: The switch valve (43) is provided at the oil outlet of the pilot valve group (40), and a second pilot control oil circuit (42) connected to the motor brake of the rotary motor (24) is formed therein, and the switch valve is arranged in the second pilot control oil circuit (42).

6. The hydraulic control system according to claim 4, characterized in that: The controller (100) is configured to: Acquiring in real time an oil pressure detection value of the oil delivery port of the load-sensitive variable displacement pump (31) and a rotation angle detection value and / or rotation speed detection value of the valve core drive motor (23); Determining that the oil pressure detection value is greater than a preset safety threshold, and the rotation angle detection value and / or the rotation speed detection value are abnormal values; The first electric proportional pressure reducing valve (2) is controlled to open the unloading valve (1) to perform an unloading action.

7. The hydraulic control system according to claim 6, characterized in that: The controller (100) is also configured to: After the unloading action is performed, the oil pressure detection value of the pumping oil port of the load-sensitive variable pump (31) is obtained again; Determining that the oil pressure detection value is still greater than the preset safety threshold; The second electric proportional pressure reducing valve (32) is controlled so that the load-sensitive variable displacement pump (31) operates at a minimum displacement condition.

8. The hydraulic control system according to claim 7, characterized in that: The controller (100) is also configured to: After the load-sensitive variable displacement pump (31) operates in a minimum displacement condition, obtaining again a detection value of the oil pressure of the oil pumping port of the load-sensitive variable displacement pump (31); Determining that the oil pressure detection value is still greater than the preset safety threshold; The speed of the engine driving the load-sensing variable displacement pump (31) is controlled to be reduced until the engine stops working.

9. An operating machine, characterized in that: The working machine includes a hydraulic control system according to any one of claims 1 to 8.

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