Horizontal pushing loading hydraulic control system and method of face shovel excavator and face shovel excavator

Abstract

The invention provides a horizontal pushing loading hydraulic control system and method of a face excavator and the face excavator, and the horizontal pushing loading hydraulic control system of the face excavator comprises a detection module used for detecting target parameters and sending target signals; the control module is used for receiving the target signal and judging whether a bucket of the face excavator is located at a working node of horizontal pushing loading or not based on the target signal; the overflow valve group is communicated with a rodless cavity of a movable arm oil cylinder of the face excavator, the overflow valve group at least comprises high overflow working pressure A and low overflow working pressure B which are used for controlling the working pressure of the rodless cavity of the movable arm oil cylinder, the system pressure of the face excavator is C, and C is larger than or equal to A and larger than B; when the bucket is located at the working node of horizontal pushing loading, the control module controls the overflow valve set to operate under the low overflow working pressure B, so that when the pressure of the rodless cavity of the movable arm oil cylinder exceeds the low overflow working pressure B, hydraulic oil in the rodless cavity of the movable arm oil cylinder overflows, and automatic falling of the movable arm is achieved.

Description

Technical Field

[0001] The present application relates to the technical field of engineering vehicles, and in particular to a hydraulic control system and method for push loading of a face shovel excavator, and the face shovel excavator. Background Art

[0002] The front shovel working device is commonly found in large or super-large hydraulic excavators. At present, front shovel excavators are all composite working devices with boom, dipper rod, bucket, and bucket opening mechanism. When this type of excavator is used for push loading, it needs to perform a combination of several actions, namely, dipper rod extension (piston rod of dipper rod cylinder extends) + bucket retraction (piston rod of bucket cylinder extends) + boom lowering (piston rod of boom cylinder retracts). Especially in the initial stage of loading, the bucket needs to be pushed horizontally at a low position to ensure the loading degree of the bucket. Therefore, the realization of the push loading function is extremely important for front shovel excavation.

[0003] During the process of bucket loading, the boom is pressed by its own weight and the weight of the material, causing the rodless chamber of the boom cylinder to be subjected to high pressure, resulting in frequent high-pressure overflow of the boom cylinder, causing great damage to the boom cylinder. In the related technology, in order to avoid the problem of high-pressure overflow of the boom cylinder, the operator is required to adjust the boom drop at any time, which requires the operator to have a high level of operation. Summary of the invention

[0004] In view of this, the present application provides a hydraulic control system and method for push loading of a front shovel excavator, which realizes automatic overflow of the boom cylinder under low overflow pressure, prolongs the service life of the hydraulic components, and improves loading efficiency. In addition, the present application also provides a hydraulic control method for push loading of a front shovel excavator and a front shovel excavator including the hydraulic control system for push loading of the front shovel excavator.

[0005] In order to achieve the above objectives, this application provides the following technical solutions:

[0006] A hydraulic control system for horizontal push loading of a front shovel excavator, comprising:

[0007] A detection module, used to detect target parameters and send target signals;

[0008] A control module receives the target signal and determines whether the bucket of the front shovel excavator is at a working node of push loading based on the target signal;

[0009] A relief valve group is connected to the rodless chamber of the boom cylinder of the front shovel excavator, and the relief valve group at least includes a high relief working pressure A and a low relief working pressure B for controlling the working pressure of the rodless chamber of the boom cylinder. The system pressure of the front shovel excavator is C, wherein A≥C>B;

[0010] Among them, when the bucket is at the working node of push loading, the control module controls the overflow valve group to operate under the low overflow working pressure B, so that when the rodless chamber pressure of the boom cylinder exceeds the low overflow working pressure B, the hydraulic oil in the rodless chamber of the boom cylinder overflows to realize the automatic lowering of the boom.

[0011] Optionally, in the above-mentioned push loading hydraulic control system of the face shovel excavator, the target parameters include the rodless chamber pressure of the bucket cylinder of the face shovel excavator, the opening signal of the first valve in the main valve bucket link of the face shovel excavator, and the opening pilot signal of the second valve in the main valve boom link of the face shovel excavator;

[0012] Among them, the first valve is used to control the oil inlet into the rodless chamber of the boom cylinder, and the second valve is used to control the oil inlet into the rodless chamber of the boom cylinder.

[0013] Optionally, in the above-mentioned push loading hydraulic control system of the face shovel excavator, the low overflow working pressure B≥D, where D is the maximum pressure value of the rodless chamber of the boom cylinder when the bucket of the face shovel excavator in a fully loaded state is stationary.

[0014] Optionally, in the push loading hydraulic control system of the above-mentioned face shovel excavator, CB≥3Mpa.

[0015] Optionally, in the above-mentioned push loading hydraulic control system of the front shovel excavator, the detection module includes:

[0016] A pressure sensor is used to obtain the rodless chamber pressure of the boom cylinder.

[0017] Optionally, in the above-mentioned push loading hydraulic control system of the face shovel excavator, the rodless chamber pressure of the boom cylinder is greater than 60% of C, the opening of the first valve is greater than 70%, the opening pilot signal of the second valve is 0, and the control module determines that the bucket is at a working node for push loading.

[0018] Optionally, in the above-mentioned push loading hydraulic control system of the front shovel excavator, the relief valve group includes:

[0019] A reversing valve and a hydraulically controlled secondary relief valve connected in series with the reversing valve, wherein the reversing valve is connected to a pilot pump of the face shovel excavator, and the hydraulically controlled secondary relief valve is connected to a rodless chamber of the boom cylinder;

[0020] Wherein, through the pilot oil provided by the pilot pump, the reversing valve can be switched between the first working position and the second working position, so that the hydraulically controlled secondary relief valve can be switched between the high relief working pressure A and the low relief working pressure B.

[0021] Optionally, in the above-mentioned push loading hydraulic control system of the face shovel excavator, the relief valve group includes an electromagnetic proportional relief valve, and the electromagnetic proportional relief valve is capable of switching between the high relief working pressure A and the low relief working pressure B.

[0022] A hydraulic control method for push loading of a front shovel excavator comprises the following steps:

[0023] Detecting target parameters and sending target signals, the target parameters including the rodless chamber pressure of the boom cylinder of the face shovel excavator, the opening signal of the first valve in the main valve boom link of the face shovel excavator, and the opening pilot signal of the second valve in the main valve boom link of the face shovel excavator;

[0024] receiving the target signal, and determining whether the bucket of the face shovel excavator is at a working node of push loading based on the target signal;

[0025] When the bucket is at the working node of horizontal push loading, the overflow valve group is controlled to operate at a low overflow working pressure B, so that when the rodless chamber pressure of the boom cylinder of the front shovel excavator exceeds the low overflow working pressure B, overflow occurs, and the boom is automatically dropped;

[0026] Among them, the overflow valve group is connected to the rodless chamber of the boom cylinder, and the overflow valve group includes at least a high overflow working pressure A and a low overflow working pressure B that can control the working pressure of the rodless chamber of the boom cylinder. The system pressure of the hydraulic system is C, wherein A≥C>B.

[0027] The present application provides a hydraulic control system for push loading of a front shovel excavator, including a relief valve group connected to the rodless chamber of the boom cylinder, the relief valve group can make the rodless chamber of the boom cylinder operate under high overflow working pressure A and low overflow working pressure B, the system pressure of the hydraulic system is C, wherein A≥C>B; the detection module detects the target parameter and sends the target signal; the control module receives the target signal, and determines whether the bucket is in the working node of push loading based on the target signal. If the bucket is in the working node of push loading, the relief valve group operates under the low overflow working pressure B, and when the rodless chamber pressure of the boom cylinder exceeds the low overflow working pressure B, the hydraulic oil in the rodless chamber of the boom cylinder overflows, thereby realizing the automatic drop of the boom under the low overflow working pressure B, extending the service life of the hydraulic components, and improving the loading efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0029] Figure 1 A schematic diagram of a hydraulic control system for a front shovel loading machine provided in an embodiment of the present application;

[0030] Figure 2 A schematic diagram of a main valve arm connection provided in an embodiment of the present application;

[0031] Figure 3 A schematic diagram of a main valve arm connection provided in an embodiment of the present application;

[0032] Figure 4 A schematic structural diagram of a front shovel excavator provided in an embodiment of the present application.

[0033] exist Figure 1-Figure 4 middle:

[0034] 1. Control module; 2. Bucket cylinder; 3. Bucket; 4. Boom cylinder; 5. Boom; 6. Arm cylinder; 7. First valve; 8. Second valve; 21. Reversing valve; 22. Hydraulically controlled secondary relief valve; 9. Pressure sensor; 10. Pilot pump; 11. Arm; 12. Power source; 13. Main pump; 14. Fuel tank; 15. Main valve arm connection; 16. Main valve boom connection; 17. Main relief valve; 18. Third valve; 19. Fourth valve. DETAILED DESCRIPTION

[0035] The present application provides a hydraulic control system for push loading of a front shovel excavator, which realizes automatic overflow of a boom cylinder at a low overflow pressure, prolongs the service life of hydraulic components, and improves loading efficiency. In addition, the present application also provides a hydraulic control method for push loading of a front shovel excavator including the hydraulic control system for push loading of a front shovel excavator and a front shovel excavator.

[0036] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0037] The front shovel excavator includes a boom 5, a bucket 3, and an arm 11 connecting the boom 5 and the bucket 3, and an arm cylinder 4, a bucket cylinder 2, and an arm cylinder 6 that respectively drive the boom 5, the bucket 3, and the arm 11 to move in sequence. Driven by the boom cylinder 4, the bucket cylinder 2, and the arm cylinder 6, the bucket 3 can at least rotate in a horizontal direction, move closer to the location of the materials, and be lifted or lowered to complete different work tasks. The front shovel excavator has a main pump 13 driven by a power source 12 to extract hydraulic oil from a tank 14 and convert the hydraulic oil into high-pressure hydraulic oil; the pilot pump 10 provides pressure oil for the control circuit to control the output of the main pump 13 and the action of the actuator; the main valve boom link 15 of the front shovel excavator is connected to the boom cylinder 6 through a hydraulic oil circuit to control the oil inlet to the rodless chamber and the rod chamber of the boom cylinder 6 to achieve the extension or recovery of the boom 11; the main valve boom link 16 of the front shovel excavator is connected to the boom cylinder 4 through a hydraulic oil circuit to control the oil inlet to the rodless chamber and the rod chamber of the boom cylinder 4 to achieve the lifting or lowering of the boom 5.

[0038] When the front shovel excavator is at the working node of push loading, the bucket 3 rotates clockwise under the drive of the bucket cylinder 2, and the dipper arm 11 is pushed outward (i.e., the position where the material is located) under the drive of the dipper arm cylinder 6. The boom 5 needs to fall to cooperate with the bucket 3 to complete the push loading. However, in the prior art, high-pressure overflow often occurs when the boom 5 falls, that is, overflow occurs only when the pressure exceeds the high-pressure section pressure of the port overflow valve that protects the boom cylinder.

[0039] like Figure 1-Figure 4 As shown, the embodiment of the present application provides a hydraulic control system for horizontal loading of a front shovel excavator, the system includes a detection module, a control module 1 and a relief valve group. The relief valve group includes a high relief working pressure A and a low relief working pressure B, and the relief valve group is connected to the rodless chamber of the boom cylinder 4 of the front shovel excavator to control the working pressure of the rodless chamber of the boom cylinder 4 to switch between the high relief working pressure A and the low relief working pressure B, wherein A≥C>B, C is the working pressure of the front shovel excavator.

[0040] Specifically, the detection module is used to detect the target parameters and send the target signal to the control module 1. The control module 1 determines whether the bucket 3 of the face shovel excavator is in the working node of push loading based on the target signal. If it is in the working node of push loading, the controller sends an instruction to switch the overflow valve group to operate under the low overflow working pressure B, so that the rodless chamber pressure of the boom cylinder 4 exceeds the low overflow working pressure and overflow occurs. In this way, the boom 5 is automatically lowered under the low overflow working pressure, thereby extending the service life of the hydraulic components and avoiding the vehicle operator from frequently operating the operating lever of the boom 5, reducing the operating difficulty of the vehicle operator, making the process of push loading smoother and improving the loading efficiency.

[0041] It should be noted that, generally, the high overflow working pressure A is greater than the system pressure C, wherein the high overflow working pressure A is set to protect the safe use of the oil cylinder.

[0042] In a certain example, the high overflow working pressure A is 2-3 MPa higher than the system pressure C, where A=37 MPa and C=34 MPa.

[0043] In actual projects, the system pressure C of different types of face shovel excavators has different pressure values. For face shovel excavators with a larger system pressure C, in order to better protect the oil cylinder, the difference between the high overflow working pressure A and the system pressure C can be greater than 3Mpa. The specific selection value of the high overflow working pressure A depends on the actual situation.

[0044] Furthermore, the target parameters include the rodless chamber pressure of the arm cylinder 6 of the front shovel, the opening signal of the first valve 7 in the main valve arm link 15 of the front shovel, and the opening pilot signal of the second valve 8 in the main valve boom link 16 of the front shovel; wherein the first valve 7 is used to control the oil inlet of the rodless chamber of the arm cylinder 6, and the second valve 8 is used to control the oil inlet of the rodless chamber of the boom cylinder 4. Because when the bucket 3 is at the working node of horizontal push loading, the piston rod of the arm cylinder 6 extends, and when the piston rod extends, the pilot pressure of the arm cylinder 6 reaches a specified value (the selection of this value is related to the opening of the first valve 7 and the system pressure of the front shovel), and when preparing for loading, the rodless chamber pressure of the arm cylinder 6 reaches a specified value (the selection of this value is related to the system pressure), and at the same time, the boom 5 has no lifting action (the piston rod of the boom cylinder 4 is not extended in the original state). By detecting the above target parameters, the control module 1 can directly determine whether the front shovel excavator is in the working node of push loading, which is convenient for the rapid response of the system.

[0045] In some other optional embodiments, the target parameters may also be parameters that indirectly feedback whether the bucket 3 is in a working node of push loading, for example, the pressure of the rod chamber of the boom cylinder 6 (the rodless chamber pressure is inferred from this pressure), the opening state of the third valve 18 (the third valve 18 is used to control the oil inlet into the rod chamber of the boom cylinder 4, and the state of the second valve 8 is deduced from the state of the third valve 18), and the opening signal of the fourth valve 19 (the fourth valve 19 is used to control the oil inlet into the rod chamber of the boom cylinder 6, and the opening of the first valve 7 is deduced from the opening of the fourth valve 19).

[0046] In some optional embodiments, the low overflow working pressure B≥D, where D is the maximum pressure value of the rodless chamber of the boom cylinder 4 when the bucket 3 of the fully loaded front shovel is stationary. In this way, the bucket 3 is prevented from falling uncontrollably when the front shovel stops at any position, thereby preventing a safety accident. The setting of the low overflow working pressure B≥D improves safety.

[0047] In some optional embodiments, CB≥3Mpa, that is, the pressure of the front shovel is at least 3Mpa greater than the low overflow working pressure, so that the rodless chamber pressure of the boom cylinder 4 can overflow at a lower working pressure, further improving the life of the hydraulic components.

[0048] In some optional embodiments, the detection module includes: a pressure sensor 9 for obtaining the rodless cavity pressure of the boom cylinder 6. The pressure sensor 9 can directly obtain the rodless cavity pressure of the boom cylinder 6, thereby improving the detection speed of the detection module.

[0049] In some optional embodiments, the rodless chamber pressure of the arm cylinder 6 is greater than 60% of C, the opening of the first valve 7 is greater than 70%, and the opening pilot signal of the second valve 8 is 0, and the control module 1 determines that the bucket 3 is at the working node of flat push loading. In a certain example, when the front shovel excavator has no boom 5 lifting action (the lifting pilot pressure is 0), there is an arm push command (the push pilot pressure>20bar) and the rodless chamber pressure of the arm cylinder 6 is greater than 28MPa, the control system determines that the machine is at the working node of flat push loading.

[0050] It should be noted that the values ​​of the above target parameters are optimal values, and in some systems, they may also be close to the above selected values.

[0051] In some optional embodiments, the relief valve group includes: a reversing valve 21 and a hydraulically controlled secondary relief valve 22 connected in series with the reversing valve 21, the reversing valve 21 is connected to the pilot pump 10 of the front shovel excavator, and the hydraulically controlled secondary relief valve 22 is connected to the rodless chamber of the boom cylinder 4; wherein, through the pilot oil provided by the pilot pump 10, the reversing valve 21 can be switched between the first working position and the second working position, so that the hydraulically controlled secondary relief valve 22 can be switched between the high relief working pressure A and the low relief working pressure B. It can be seen that the relief valve group has a simple structure and a simple operating principle.

[0052] In some optional embodiments, the relief valve group is composed of an electromagnetic proportional relief valve, which can switch between a high relief working pressure A and a low relief working pressure B. When the system needs to work in two different pressure stages, the pressure can be automatically adjusted by changing the current signal input to the electromagnetic proportional relief valve. The continuous control characteristics of this valve enable it to automatically compensate and control the target according to the information collected, and realize a series of continuously controllable follow-up actions. In other words, the selection of the working pressure of the electromagnetic proportional relief valve is more flexible, and it can be adapted to more front shovel excavators, thereby improving the practicality of the system.

[0053] In some other optional embodiments, the relief valve group may also be an electrically controlled secondary relief valve.

[0054] The present application also provides a hydraulic control method for push loading of a front shovel excavator, comprising the following steps:

[0055] Detect target parameters and send target signals, the target parameters include the rodless chamber pressure of the boom cylinder 6 of the face shovel excavator, the opening signal of the first valve 7 in the main valve boom link 15 of the face shovel excavator, and the opening pilot signal of the second valve 8 in the main valve boom link 16 of the face shovel excavator; receive the target signal, and judge whether the bucket 3 of the face shovel excavator is in the working node of horizontal push loading based on the target signal; when the bucket 3 is in the working node of horizontal push loading, control the overflow valve group to operate under the low overflow working pressure B, so that when the rodless chamber pressure of the boom cylinder 4 of the face shovel excavator exceeds the low overflow working pressure B, overflow occurs, and the boom 5 is automatically lowered; wherein, the overflow valve group is connected to the rodless chamber of the boom cylinder 4, and the overflow valve group at least includes a high overflow working pressure A and a low overflow working pressure B that can control the rodless chamber working pressure of the boom cylinder 4, and the system pressure of the hydraulic system is C, wherein A≥C>B.

[0056] The basic principles of the present application are described above in conjunction with specific embodiments. However, it should be noted that the advantages, strengths, effects, etc. mentioned in the present application are only examples and not limitations, and it cannot be considered that these advantages, strengths, effects, etc. are required by each embodiment of the present application. In addition, the specific details disclosed above are only for the purpose of illustration and ease of understanding, not for limitation, and the above details do not limit the present application to being implemented by adopting the above specific details.

[0057] The block diagrams of the devices, apparatuses, equipment, and systems involved in this application are only illustrative examples and are not intended to require or imply that they must be connected, arranged, and configured in the manner shown in the block diagram. As will be appreciated by those skilled in the art, these devices, apparatuses, equipment, and systems can be connected, arranged, and configured in any manner. Words such as "including", "comprising", "having", etc. are open words, referring to "including but not limited to", and can be used interchangeably with them. The words "or" and "and" used here refer to the words "and / or" and can be used interchangeably with them, unless the context clearly indicates otherwise. The words "such as" used here refer to the phrase "such as but not limited to", and can be used interchangeably with them.

[0058] It should also be noted that in the apparatus, device and method of the present application, each component or each step can be decomposed and / or recombined. Such decomposition and / or recombination should be regarded as equivalent solutions of the present application.

[0059] The above description of the disclosed aspects is provided to enable any person skilled in the art to make or use the present application. Various modifications to these aspects will be readily apparent to those skilled in the art, and the general principles defined herein may be applied to other aspects without departing from the scope of the present application. Therefore, the present application is not intended to be limited to the aspects shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

[0060] It should be understood that the qualifiers "first", "second", "third", "fourth", "fifth" and "sixth" used in the description of the embodiments of the present application are only used to more clearly explain the technical solutions and cannot be used to limit the scope of protection of the present application.

[0061] The above description has been given for the purpose of illustration and description. In addition, this description is not intended to limit the embodiments of the present application to the forms disclosed herein. Although multiple example aspects and embodiments have been discussed above, those skilled in the art will recognize certain variations, modifications, changes, additions and sub-combinations thereof.

Claims

1. A hydraulic control system for horizontal push loading of a front shovel excavator, characterized in that: include: A detection module, used to detect target parameters and send target signals; A control module (1) receives the target signal and determines, based on the target signal, whether the bucket (3) of the front shovel excavator is at a working node of push loading; A relief valve group is connected to the rodless chamber of the boom cylinder (4) of the front shovel excavator, and the relief valve group at least includes a high relief working pressure A and a low relief working pressure B for controlling the working pressure of the rodless chamber of the boom cylinder (4). The system pressure of the front shovel excavator is C, wherein A≥C>B; When the bucket (3) is at a working node of horizontal push loading, the control module (1) controls the overflow valve group to operate under the low overflow working pressure B, so that when the rodless chamber pressure of the boom cylinder (4) exceeds the low overflow working pressure B, the hydraulic oil in the rodless chamber of the boom cylinder (4) overflows to realize the automatic lowering of the boom (5).

2. The push loading hydraulic control system of a front shovel excavator according to claim 1, characterized in that: The target parameters include the rodless chamber pressure of the boom cylinder (6) of the front shovel excavator, the opening signal of the first valve (7) in the main valve boom link (15) of the front shovel excavator, and the opening pilot signal of the second valve (8) in the main valve boom link (16) of the front shovel excavator; The first valve (7) is used to control the oil inlet to the rodless chamber of the boom cylinder (6), and the second valve (8) is used to control the oil inlet to the rodless chamber of the boom cylinder (4).

3. The push loading hydraulic control system of a front shovel excavator according to claim 1, characterized in that: The low overflow working pressure B≥D, where D is the maximum pressure value of the rodless chamber of the boom cylinder (4) when the bucket (3) of the face shovel excavator in a fully loaded state is stationary.

4. The push loading hydraulic control system of a front shovel excavator according to claim 1, characterized in that: CB≥3Mpa.

5. The push loading hydraulic control system of a front shovel excavator according to claim 2, characterized in that: The detection module comprises: A pressure sensor (9) for obtaining the rodless chamber pressure of the boom cylinder (6).

6. The push loading hydraulic control system of a front shovel excavator according to claim 2, characterized in that: The rodless chamber pressure of the boom cylinder (6) is greater than 60% of C, the opening of the first valve (7) is greater than 70%, the opening pilot signal of the second valve (8) is 0, and the control module determines that the bucket (3) is at a working node of horizontal push loading.

7. The push loading hydraulic control system of a front shovel excavator according to claim 1, characterized in that: The relief valve group comprises: A reversing valve (21) and a hydraulically controlled secondary overflow valve (22) connected in series with the reversing valve, wherein the reversing valve (21) is connected to a pilot pump (10) of the front shovel excavator, and the hydraulically controlled secondary overflow valve (22) is connected to a rodless chamber of the boom cylinder (4); Wherein, through the pilot oil provided by the pilot pump (10), the reversing valve (21) can be switched between the first working position and the second working position, so that the hydraulically controlled secondary relief valve (22) can be switched between the high relief working pressure A and the low relief working pressure B.

8. The push loading hydraulic control system of a front shovel excavator according to claim 1, characterized in that: The relief valve group includes an electromagnetic proportional relief valve, and the electromagnetic proportional relief valve can be switched between the high relief working pressure A and the low relief working pressure B.

9. A hydraulic control method for push loading of a front shovel excavator, characterized in that: The following steps are involved: Detecting target parameters and sending target signals, the target parameters including the rodless chamber pressure of the boom cylinder (6) of the face shovel excavator, the opening signal of the first valve (7) in the main valve boom link (15) of the face shovel excavator, and the opening pilot signal of the second valve (8) in the main valve boom link (16) of the face shovel excavator; receiving the target signal, and judging whether the bucket (3) of the front shovel excavator is at a working node of push loading based on the target signal; When the bucket (3) is at a working node of horizontal push loading, the overflow valve group is controlled to operate at a low overflow working pressure B, so that when the rodless chamber pressure of the boom cylinder (4) of the front shovel excavator exceeds the low overflow working pressure B, overflow occurs, thereby realizing automatic lowering of the boom; The overflow valve group is connected to the rodless chamber of the boom cylinder (4), and the overflow valve group at least includes a high overflow working pressure A and a low overflow working pressure B capable of controlling the working pressure of the rodless chamber of the boom cylinder (4). The system pressure of the front shovel excavator is C, wherein A≥C>B.

10. A front shovel excavator, characterized in that: A push loading hydraulic control system for a front shovel excavator comprising the method described in any one of claims 1 to 8.

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