Movable arm hydraulic control system of engineering equipment and engineering equipment

Abstract

The utility model provides a movable arm hydraulic control system of engineering equipment and the engineering equipment. The system comprises a main pump, a main valve movable arm valve link, a pilot control handle and a movable arm oil cylinder. The main valve movable arm valve linkage is at least provided with a first working position, a second working position and a middle position, and the pilot control handle is at least provided with a first control position and a second control position. A first oil outlet of the pilot control handle is connected with a first pilot cavity of the main valve movable arm valve link, and a second oil outlet of the pilot control handle is connected with a second pilot cavity of the main valve movable arm valve link; when the main valve movable arm valve connector is located at the first control position, the main valve movable arm valve connector is located at the first working position, part of high-pressure oil ports are communicated with a rod cavity of the movable arm oil cylinder, and the rest of the high-pressure oil ports enter an oil return channel; when the main valve movable arm valve connector is located at the second control position, the main valve movable arm valve connector is located at the second working position, and all the high-pressure oil ports are communicated with a rod cavity of the movable arm oil cylinder; according to the utility model, the smoothness of the descending action of the movable arm and the powerful vehicle supporting operation of the movable arm can be considered.

Description

Technical Field

[0001] The utility model relates to the technical field of hydraulic engineering machinery, in particular to a boom hydraulic control system for engineering equipment and the engineering equipment. Background Art

[0002] At present, the overall controllability and coordination of an excavator are one of the key indicators to measure the overall performance of an excavator; in addition, the car-supporting ability of the working device of the whole vehicle is another important indicator to evaluate the working ability of an excavator. Generally, during the commissioning process of a new machine, in order to ensure that there is less jitter impact when the boom lowering action starts and stops during the process, a flow splitting treatment is performed at the lowering position of the boom spool. Part of the working oil entering the boom connection of the main pump enters the small chamber of the boom cylinder, and the other small part of the working oil returns to the oil in advance to ensure the stability and smoothness of the single action and compound action of the boom with a small flow rate; however, when the boom is lowered to support the vehicle during operation, as little flow splitting treatment as possible is required at the lowering position of the boom, and the main pump needs to allocate more flow to the boom cylinder to ensure sufficient flow required to establish the set pressure during car support; therefore, it is difficult to simultaneously take into account the smoothness and coordination of the boom lowering action and the strong car-supporting force during the boom car-supporting operation.

[0003] Therefore, there is an urgent need for a boom hydraulic control system for engineering equipment and the engineering equipment, which can take into account the smoothness and coordination of the boom lowering action and the strong car-supporting force during the boom car-supporting operation. Summary of the Utility Model

[0004] The purpose of the utility model is to provide a boom hydraulic control system for engineering equipment and the engineering equipment, aiming to solve the technical problem that it is difficult for the traditional boom hydraulic control system to simultaneously take into account the smoothness and coordination of the boom lowering action and the strong car-supporting force during the boom car-supporting operation.

[0005] To achieve the above purpose, in the first aspect, the utility model provides a boom hydraulic control system for engineering equipment, including: a main pump, a main valve boom valve connection connected to the oil outlet of the main pump, a pilot control handle, and a boom cylinder;

[0006] The main valve boom valve connection has at least a first working position, a second working position, and a neutral position, and the pilot control handle has at least a first control position and a second control position;

[0007] The first oil outlet of the pilot control handle is connected to the first pilot chamber of the main valve boom valve connection, and the second oil outlet of the pilot control handle is connected to the second pilot chamber of the main valve boom valve connection;

[0008] When the pilot control handle is in the first control position, the pilot control oil enters the first pilot chamber under the action of the first pressure from the first oil outlet, so that the main valve boom valve assembly is in the first working position. Part of the high-pressure oil ports of the main valve boom valve assembly communicate with the rod chamber of the boom cylinder, and the remaining part enters the oil return passage to realize the smooth lowering of the boom.

[0009] When the pilot control handle is in the second control position, the pilot control oil enters the first pilot chamber under the action of the second pressure from the first oil outlet, so that the main valve boom valve assembly is in the second working position. All the high-pressure oil ports of the main valve boom valve assembly communicate with the rod chamber of the boom cylinder to perform the strong vehicle support action during the lowering of the boom.

[0010] As a further improvement of the above solution, the main valve boom valve assembly further has a third working position, and the pilot control handle further has a third control position. When the pilot control handle is in the third control position, the pilot control oil enters the second pilot chamber from the second oil outlet, so that the main valve boom valve assembly is in the third working position. All the high-pressure oil ports of the main valve boom valve assembly communicate with the rodless chamber of the boom cylinder to realize the lifting of the boom.

[0011] As a further improvement of the above solution, the main valve boom valve assembly is a pilot-operated hydraulic four-position eight-way valve.

[0012] As a further improvement of the above solution, the valve body of the main valve boom valve assembly is provided with a first working oil port, a second working oil port, a third working oil port, a fourth working oil port, a fifth working oil port, a sixth working oil port, a seventh working oil port and an eighth working oil port;

[0013] The oil outlet of the main pump is communicated with the seventh working oil port through the main pipeline. The main pipeline is also provided with a bypass pipeline. One end of the bypass pipeline is communicated with the main pipeline, and the other end is connected with the sixth working oil port;

[0014] The first working oil port is connected with the rod chamber of the boom cylinder, and the second working oil port is connected with the rodless chamber of the boom cylinder; the third working oil port and the fourth working oil port are respectively connected with the fuel tank; the fifth working oil port and the eighth working oil port are respectively connected with the fuel tank;

[0015] The first working oil port is also connected with the fuel tank through the first safety valve; the second working oil port is also connected with the fuel tank through the second safety valve.

[0016] As a further improvement of the above solution, a first one-way valve and a second one-way valve with the same conduction direction are successively connected in series on the bypass pipeline, and both one-way valves are unidirectionally conductive from the main pump to the sixth working oil port direction.

[0017] As a further improvement of the above solution, a branch oil pipe is provided between the first one-way valve and the second one-way valve, and the other end of the branch oil pipe is connected to the fuel tank.

[0018] As a further improvement of the above solution, when the main valve boom valve union is in the neutral position, the seventh working oil port is communicated with the third working oil port, the eighth working oil port is communicated with the fourth working oil port, the first working oil port is not communicated with the fifth and sixth working oil ports, and the second working oil port is not communicated with the fifth and sixth working oil ports;

[0019] When the main valve boom valve union is in the first working position, the first working oil port is communicated with the sixth working oil port, the second working oil port is communicated with the fifth working oil port, the third working oil port is communicated with the seventh working oil port, and the fourth working oil port is not communicated with the eighth working oil port;

[0020] When the main valve boom valve union is in the second working position, the first working oil port is communicated with the sixth working oil port, the second working oil port is communicated with the fifth working oil port, the third working oil port is not communicated with the seventh working oil port, and the fourth working oil port is not communicated with the eighth working oil port;

[0021] When the main valve boom valve union is in the third working position, the first working oil port is communicated with the fifth working oil port, the second working oil port is communicated with the sixth working oil port, the third working oil port is not communicated with the seventh working oil port, and the fourth working oil port is not communicated with the eighth working oil port.

[0022] In a second aspect, the present invention further provides a construction equipment, including the boom hydraulic control system of the construction equipment provided in the first aspect.

[0023] Since the present invention adopts the above technical solutions, the beneficial effects of the present application are as follows:

[0024] The present utility model provides a boom hydraulic control system for engineering equipment. By correspondingly setting corresponding working positions at the boom valve bank of the main valve, and at the same time controlling the pilot control oil to flow into the corresponding pilot oil ports through the pilot control handle, the spool of the boom valve bank of the main valve is driven to move to the corresponding working position. Specifically, when the pilot control handle is in the first control position, under the action of the first pressure, the pilot control oil enters the first pilot chamber from the first oil outlet so that the boom valve bank of the main valve is in the first working position. Part of the high-pressure oil ports of the boom valve bank of the main valve communicate with the rod chamber of the boom cylinder, and the remaining part enters the oil return passage to achieve smooth and fine lowering of the boom. When the pilot control handle is in the second control position, under the action of the second pressure, the pilot control oil enters the first pilot chamber from the first oil outlet so that the boom valve bank of the main valve is in the second working position. All the high-pressure oil ports of the boom valve bank of the main valve communicate with the rod chamber of the boom cylinder to perform the strong vehicle support action during boom lowering. Thus, the boom hydraulic control system provided by the present utility model can take into account both the fine and smooth action of boom lowering and the strong vehicle support action during boom lowering. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the embodiments of the present utility model or the technical solutions in the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present utility model. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on the structures shown in these drawings.

[0026] Figure 1 is a schematic diagram of the principle of a boom hydraulic control system for an engineering equipment disclosed by the present utility model;

[0027] Figure 2 is a front view schematic diagram of the spool of the boom valve bank of the main valve disclosed by the present utility model.

[0028] Reference numerals:

[0029] 1, main pump; 2, boom valve bank of the main valve; 21, first pilot chamber; 22, second pilot chamber; 3, pilot control handle; 31, first oil outlet; 32, second oil outlet; 4, boom cylinder; 5, fuel tank; 6, first safety valve; 7, second safety valve; 8, main pipeline; 9, bypass pipeline; 91, first one-way valve; 92, second one-way valve; 93, branch oil pipe;

[0030] A, first working position; B, second working position; C, middle position; D, third working position;

[0031] a, the first working oil port; b, the second working oil port; c, the third working oil port; d, the fourth working oil port; e, the fifth working oil port; f, the sixth working oil port; g, the seventh working oil port; h, the eighth working oil port.

[0032] The realization of the purpose, functional characteristics and advantages of the present utility model will be further described in conjunction with the embodiments with reference to the accompanying drawings. Specific embodiments

[0033] Next, the technical solutions in the embodiments of the present utility model will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present utility model. Obviously, the described embodiments are only a part of the embodiments of the present utility model, rather than all the embodiments. Based on the embodiments in the present utility model, all other embodiments obtained by those of ordinary skill in the art without making creative efforts belong to the scope of protection of the present utility model.

[0034] It should be noted that all directional indications (such as up, down,...) in the embodiments of the present utility model are only used to explain the relative positional relationship and movement conditions between components in a specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indications will also change accordingly.

[0035] In addition, the descriptions such as "first" and "second" in the present utility model are only for descriptive purposes, and cannot be understood as indicating or implying their relative importance or implicitly indicating the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one of such features.

[0036] Moreover, the technical solutions between the various embodiments of the present utility model can be combined with each other, but it must be based on the fact that those of ordinary skill in the art can implement it. When the combination of technical solutions results in contradictions or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection required by the present utility model.

[0037] Embodiment 1

[0038] See Figure 1 and Figure 2 , the present utility model provides a boom hydraulic control system for an engineering equipment, including: a main pump 1, a main valve boom valve block 2 connected to the oil outlet of the main pump 1, a pilot control handle 3, and a boom cylinder 4;

[0039] The main valve boom valve block 2 has at least a first working position A, a second working position B, a neutral position C, and a third working position D, and the pilot control handle 3 has at least a first control position, a second control position, and a third control position;

[0040] The first oil outlet 31 of the pilot control handle 3 is connected to the first pilot chamber 21 of the main valve boom valve union 2, and the second oil outlet 32 of the pilot control handle 3 is connected to the second pilot chamber 22 of the main valve boom valve union 2;

[0041] When the pilot control handle 3 is in the first control position, under the action of the first pressure, the pilot control oil enters the first pilot chamber 21 from the first oil outlet 31 to make the main valve boom valve union 2 in the first working position A. Part of the high-pressure oil ports of the main valve boom valve union 2 communicate with the rod chamber of the boom cylinder 4, and the remaining part enters the oil return passage, so as to achieve fine and smooth operation of the boom with small flow when the main valve boom valve union 2 performs downward flow distribution;

[0042] When the pilot control handle 3 is in the second control position, under the action of the second pressure, the pilot control oil enters the first pilot chamber 21 from the first oil outlet 31 to make the main valve boom valve union 2 in the second working position B. All the high-pressure oil ports of the main valve boom valve union 2 communicate with the rod chamber of the boom cylinder 4, so as to achieve full-flow oil supply of the main valve boom valve union 2 and strong vehicle support action for boom lowering with large flow;

[0043] In the present utility model, by correspondingly arranging corresponding working positions on the main valve boom valve union 2, and at the same time controlling the pilot control oil to flow into the corresponding pilot oil ports through the pilot control handle 3, the spool of the main valve boom valve union 2 is driven to move to the corresponding working position; specifically, when the pilot control handle 3 is in the first control position, under the action of the first pressure, the pilot control oil enters the first pilot chamber 21 from the first oil outlet 31 to make the main valve boom valve union 2 in the first working position A. Part of the high-pressure oil ports of the main valve boom valve union 2 communicate with the rod chamber of the boom cylinder 4, and the remaining part enters the oil return passage to achieve smooth and fine lowering of the boom; when the pilot control handle 3 is in the second control position, under the action of the second pressure, the pilot control oil enters the first pilot chamber 21 from the first oil outlet 31 to make the main valve boom valve union 2 in the second working position B. All the high-pressure oil ports of the main valve boom valve union 2 communicate with the rod chamber of the boom cylinder 4 to perform the strong vehicle support action for boom lowering; thus enabling the boom hydraulic control system provided by the present utility model to take into account both the fine and smooth action of boom lowering and the strong vehicle support action for boom lowering;

[0044] In addition, in the present utility model, different pilot pressures are adjusted by switching different control positions of the pilot control handle 3, so that a double working position in one or more directions of the pilot handle can be realized, and smooth switching of actions in two pressure segments in one or more directions can be achieved.

[0045] As a preferred embodiment, when the pilot control handle 3 is in the third control position, the pilot control oil enters the second pilot chamber 22 from the second oil outlet 32 to make the main valve boom valve union 2 in the third working position D. All the high-pressure oil ports of the main valve boom valve union 2 communicate with the rodless chamber of the boom cylinder 4 to realize boom lifting. With such a setting, only one main valve boom valve union 2 needs to be set, and only by switching to different working positions, while taking into account the realization of fine and smooth boom lowering actions and strong vehicle supporting actions during boom lowering, strong boom lifting can also be realized.

[0046] As a preferred embodiment, the main valve boom valve union 2 is a pilot-operated hydraulic four-position eight-way valve. Specifically, the valve body of the main valve boom valve union 2 is provided with a first working oil port a, a second working oil port b, a third working oil port c, a fourth working oil port d, a fifth working oil port e, a sixth working oil port f, a seventh working oil port g, and an eighth working oil port h.

[0047] The oil outlet of the main pump 1 is connected to the seventh working oil port g through the main pipeline 8. The main pipeline 8 is also provided with a bypass pipeline 9. One end of the bypass pipeline 9 is connected to the main pipeline 8, and the other end is connected to the sixth working oil port f.

[0048] The first working oil port a is connected to the rod chamber of the boom cylinder 4, and the second working oil port b is connected to the rodless chamber of the boom cylinder 4. The third working oil port c and the fourth working oil port d are respectively connected to the fuel tank 5. The fifth working oil port e and the eighth working oil port h are respectively connected to the fuel tank 5.

[0049] The first working oil port a is also connected to the fuel tank 5 through the first safety valve 6. The second working oil port b is also connected to the fuel tank 5 through the second safety valve 7.

[0050] When the main valve boom valve union 2 is in the neutral position C, the seventh working oil port g communicates with the third working oil port c, the eighth working oil port h communicates with the fourth working oil port d, the first working oil port a is not connected to the fifth working oil port e and the sixth working oil port f, and the second working oil port b is not connected to the fifth working oil port e and the sixth working oil port f. At this time, the pilot control oil enters the fourth working oil port d from the eighth working oil port h and then flows back to the fuel tank 5. The high-pressure oil entering from the main pump 1 directly enters the third working oil port c through the seventh working oil port g and then flows back to the fuel tank 5.

[0051] Specifically, when the operation pilot control handle 3 is pushed forward ((first control position)), the first oil outlet 31 of the pilot control handle 3 outputs pilot control oil to the first pilot chamber 21 of the main valve boom valve union 2. Preferably, the pilot control oil, under the first pressure (preferably, the first pressure range is 3 - 15 bar), pushes the spool to move leftward (preferably, the spool displacement is 6 mm). When the main valve boom valve union 2 is in the first working position A, the first working oil port a is communicated with the sixth working oil port f, the second working oil port b is communicated with the fifth working oil port e, the third working oil port c is communicated with the seventh working oil port g, and the fourth working oil port d and the eighth working oil port h are not communicated with each other; part of the high-pressure oil entering from the main pump 1 enters the first working oil port a through the sixth working oil port f, and then enters the rod chamber of the boom cylinder 4, and the remaining part of the high-pressure oil enters the third working oil port c through the seventh working oil port g and then flows back to the fuel tank 5. The low-pressure oil flowing out of the rodless chamber of the boom cylinder 4 first enters the second working oil port b and then enters the fifth working oil port e and then flows back to the fuel tank 5, so as to achieve smooth and fine lowering of the boom by flow division;

[0052] When the operation pilot control handle 3 is pushed forward forcefully to the end positioning and holding position (second control position), the first oil outlet 31 of the pilot control handle 3 outputs pilot control oil to the first pilot chamber 21 of the main valve boom valve union 2. Preferably, the pilot control oil, under the second pressure (preferably, the first pressure range is 15 - 26 bar), pushes the working spool to continue moving leftward (preferably, the spool displacement is 11 mm); when the main valve boom valve union 2 is in the second working position B, the first working oil port a is communicated with the sixth working oil port f, the second working oil port b is communicated with the fifth working oil port e, the third working oil port c and the seventh working oil port g are not communicated with each other, and the fourth working oil port d and the eighth working oil port h are not communicated with each other; all the high-pressure oil entering from the main pump 1 enters the first working oil port a through the sixth working oil port f, and then enters the rod chamber of the boom cylinder 4. The low-pressure oil flowing out of the rodless chamber of the boom cylinder 4 first enters the second working oil port b and then enters the fifth working oil port e and then flows back to the fuel tank 5, so as to achieve the lowering action of the boom with full flow and strong support;

[0053] When the operation pilot control handle 3 is in the third control position and the main valve boom valve union 2 is in the third working position D, the first working oil port a is communicated with the fifth working oil port e, the second working oil port b is communicated with the sixth working oil port f, the third working oil port c and the seventh working oil port g are not communicated with each other, and the fourth working oil port d and the eighth working oil port h are not communicated with each other; all the high-pressure oil entering from the main pump 1 enters the second working oil port b through the sixth working oil port f, and then enters the rodless chamber of the boom cylinder 4. The low-pressure oil flowing out of the rod chamber of the boom cylinder 4 first enters the first working oil port a and then enters the fifth working oil port e and then flows back to the fuel tank 5, so as to achieve the lifting action of the boom with full flow and strong force.

[0054] As a preferred embodiment, the bypass pipe 9 is sequentially connected in series with a first one-way valve 91 and a second one-way valve 92 having the same conduction direction, and both one-way valves are one-way conducting from the main pump 1 to the sixth working oil port f; with the arrangement of the two one-way valves, only the high-pressure oil output from the main pump 1 can be one-way conducting to open the two one-way valves and enter the sixth working oil port f, thereby achieving full-flow strong support and lowering of the boom or full-flow strong lifting of the boom;

[0055] Preferably, a branch oil pipe 93 is further provided between the first one-way valve 91 and the second one-way valve 92 , and the other end of the branch oil pipe 93 is connected to the oil tank 5 .

[0056] Example 2

[0057] The utility model also provides an engineering equipment, including a boom hydraulic control system of an engineering equipment provided in Example 1; the engineering equipment described in the utility model includes but is not limited to an excavator. In this embodiment, the excavator engineering equipment is taken as an example for explanation. In the excavator engineering equipment, the main pump 1 adopts a four-link main pump 1 to supply oil to the hydraulic system of the whole vehicle. The main pump 1 provides a high-pressure oil source for the movement of the boom cylinder 4. The pilot control handle 3 adjusts the flow direction and pilot pressure of the output control oil source by operating the handle forward and backward movement and the opening size. The main valve boom valve link 2 controls the pressure, flow rate and movement direction of the high-pressure oil distributed to the rod chamber and rodless chamber of the boom cylinder 4.

[0058] When the pilot control handle 3 is in the first control position, the pilot control oil enters the first pilot chamber 21 from the first oil outlet 31 under the action of the first pressure to make the main valve boom valve link 2 in the first working position A, part of the high-pressure oil ports of the main valve boom valve link 2 are connected to the rod chamber of the boom oil cylinder 4, and the remaining part enters the return oil channel, so that when the main valve boom valve link 2 is lowered and diverted, a small flow rate is used to achieve fine and stable operation of the boom;

[0059] When the pilot control handle 3 is in the second operating position, the pilot control oil enters the first pilot chamber 21 from the first oil outlet 31 under the action of the second pressure to make the main valve boom valve link 2 in the second working position B, and all the high-pressure oil ports of the main valve boom valve link 2 are connected to the rod chamber of the boom cylinder 4, so that the main valve boom valve link 2 is supplied with oil at full flow, and the large flow rate realizes the boom lowering and strong vehicle supporting action; the excavator using the boom hydraulic control system of the engineering equipment provided in Example 1 can achieve the fine and smooth lowering action of the excavator boom and the strong vehicle supporting function.

[0060] It should be noted that, in this embodiment, the pilot control handle 3 is a quadruple pilot control handle, see Figure 1, the two-stage pilot control handle on the left is used to control the boom valve bank 2 of the main valve to achieve various movements of the boom, and the two-stage pilot control handle on the right is used to control the functions of other valve banks of the main valve. The corresponding connected valve banks are not shown in Figure 1 for illustration purposes.

[0061] The above are only the preferred embodiments of the present invention, and do not limit the patent scope of the present invention. Any equivalent structural transformation made under the inventive concept of the present invention by using the content of the specification and drawings of the present invention, or any direct / indirect application in other related technical fields is included in the patent protection scope of the present invention.

Claims

1. A boom hydraulic control system for an engineering device, characterized in that, Including: A main pump, a main valve boom valve assembly connected to the oil outlet of the main pump, a pilot control handle, and a boom cylinder; The main valve boom valve assembly has at least a first working position, a second working position, and a neutral position, and the pilot control handle has at least a first control position and a second control position; The first oil outlet of the pilot control handle is connected to the first pilot chamber of the main valve boom valve assembly, and the second oil outlet of the pilot control handle is connected to the second pilot chamber of the main valve boom valve assembly; When the pilot control handle is in the first control position, the pilot control oil enters the first pilot chamber from the first oil outlet under the action of a first pressure, so that the main valve boom valve assembly is in the first working position. Part of the high-pressure oil ports of the main valve boom valve assembly communicate with the rod chamber of the boom cylinder, and the remaining part enters the oil return passage to achieve smooth lowering of the boom; When the pilot control handle is in the second control position, the pilot control oil enters the first pilot chamber from the first oil outlet under the action of a second pressure, so that the main valve boom valve assembly is in the second working position. All the high-pressure oil ports of the main valve boom valve assembly communicate with the rod chamber of the boom cylinder to perform a strong vehicle support action for lowering the boom.

2. The boom hydraulic control system of an engineering device according to claim 1, characterized in that, The main valve boom valve assembly also has a third working position, and the pilot control handle also has a third control position. When the pilot control handle is in the third control position, the pilot control oil enters the second pilot chamber from the second oil outlet, so that the main valve boom valve assembly is in the third working position. All the high-pressure oil ports of the main valve boom valve assembly communicate with the rodless chamber of the boom cylinder to achieve boom lifting.

3. The boom hydraulic control system of a construction equipment according to claim 1 or 2, characterized in that, The main valve boom valve assembly is a pilot-operated hydraulic four-position eight-way valve.

4. The boom hydraulic control system of an engineering device according to claim 1 or 2, characterized in that, On the valve body of the main valve boom valve assembly, there are provided a first working oil port, a second working oil port, a third working oil port, a fourth working oil port, a fifth working oil port, a sixth working oil port, a seventh working oil port, and an eighth working oil port; The oil outlet of the main pump is communicated with the seventh working oil port through a main pipeline, and a bypass pipeline is also provided on the main pipeline. One end of the bypass pipeline is communicated with the main pipeline, and the other end is connected to the sixth working oil port; The first working oil port is connected to the rod chamber of the boom cylinder, and the second working oil port is connected to the rodless chamber of the boom cylinder; the third working oil port and the fourth working oil port are respectively connected to the fuel tank; the fifth working oil port and the eighth working oil port are respectively connected to the fuel tank; The first working oil port is also connected to the fuel tank through a first safety valve; the second working oil port is also connected to the fuel tank through a second safety valve.

5. The boom hydraulic control system of an engineering device according to claim 4, characterized in that, A first one-way valve and a second one-way valve with the same conduction direction are sequentially connected in series on the bypass pipeline, and both one-way valves conduct unidirectionally from the main pump to the sixth working oil port direction.

6. The boom hydraulic control system of a construction equipment according to claim 5, characterized in that, A branch oil pipe is also provided between the first one-way valve and the second one-way valve, and the other end of the branch oil pipe is connected to the fuel tank.

7. The boom hydraulic control system of a construction equipment according to claim 4, characterized in that, When the main valve boom valve union is in the neutral position, the seventh working oil port communicates with the third working oil port, the eighth working oil port communicates with the fourth working oil port, the first working oil port, the fifth working oil port and the sixth working oil port do not communicate with each other, and the second working oil port, the fifth working oil port and the sixth working oil port do not communicate with each other; When the main valve boom valve union is in the first working position, the first working oil port communicates with the sixth working oil port, the second working oil port communicates with the fifth working oil port, the third working oil port communicates with the seventh working oil port, and the fourth working oil port and the eighth working oil port do not communicate with each other; When the main valve boom valve union is in the second working position, the first working oil port communicates with the sixth working oil port, the second working oil port communicates with the fifth working oil port, the third working oil port and the seventh working oil port do not communicate with each other, and the fourth working oil port and the eighth working oil port do not communicate with each other; When the main valve boom valve union is in the third working position, the first working oil port communicates with the fifth working oil port, the second working oil port communicates with the sixth working oil port, the third working oil port and the seventh working oil port do not communicate with each other, and the fourth working oil port and the eighth working oil port do not communicate with each other.

8. An engineering device, characterized in that, It includes a boom hydraulic control system for an engineering equipment as described in any one of claims 1-7.

Images