Hydraulic drive systems and construction machinery

Abstract

This invention relates to the field of engineering machinery technology, and discloses a hydraulic drive system and engineering machinery, comprising: a first valve body connected to a first variable displacement pump assembly via a first main pipeline; the first valve body is connected to an outrigger oil supply pipeline and an auxiliary steering oil supply pipeline; in a first working position, the first valve body is connected to the first main pipeline and the outrigger oil supply pipeline; in a second working position, the first valve body is connected to the first main pipeline and the auxiliary steering oil supply pipeline; one end of a first control assembly is connected to the first main pipeline, and the other end of the first control assembly is connected to an upper vehicle oil supply pipeline; the first variable displacement pump assembly can be selectively connected to the first valve body or the upper vehicle oil supply pipeline via the first control assembly. This invention allows the lower and upper vehicles to share the first variable displacement pump assembly, thereby reducing the need for a separate pump assembly, simplifying the overall structure of the hydraulic drive system, effectively controlling system costs, reducing space occupation on the vehicle body, and improving the space utilization rate of the engineering machinery.

Description

Technical Field

[0001] This invention relates to the field of engineering machinery technology, specifically to hydraulic drive systems and engineering machinery. Background Technology

[0002] Construction machinery, such as cranes, primarily consists of two hydraulic drive systems: the upper-car actuator hydraulic drive and the lower-car hydraulic drive. These two parts operate completely independently throughout the crane's operation; that is, lower-car operation is not permitted while the upper-car actuator is being operated. In existing technology, the upper-car's luffing and telescopic mechanisms are driven by independent hydraulic pumps, and the lower-car's outrigger and steering mechanisms also have independent hydraulic pumps. This results in a complex hydraulic drive system structure, high cost, and large space requirements. Summary of the Invention

[0003] In view of this, the present invention provides a hydraulic drive system and engineering machinery to solve the problems of complex structure, high cost and large space occupation of existing hydraulic drive systems.

[0004] In a first aspect, the present invention provides a hydraulic drive system, comprising: a first variable displacement pump assembly; a first valve body, connected to the first variable displacement pump assembly via a first main pipeline, the first valve body being connected to a support leg oil supply pipeline and an auxiliary steering oil supply pipeline, the first valve body having a first working position and a second working position, wherein in the first working position, the first valve body is connected to the first main pipeline and the support leg oil supply pipeline, and in the second working position, the first valve body is connected to the first main pipeline and the auxiliary steering oil supply pipeline; and a first control assembly, one end of the first control assembly being connected to the first main pipeline, and the other end of the first control assembly being connected to an upper vehicle oil supply pipeline, wherein the first variable displacement pump assembly is selectively connected to the first valve body or the upper vehicle oil supply pipeline via the first control assembly.

[0005] In one optional embodiment, the first control component includes a second valve body and a third valve body. The second valve body has a first oil delivery chamber and a first control oil chamber separated by a valve core. The first main oil inlet and the first main oil outlet of the second valve body are both connected to the first oil delivery chamber. The first main oil inlet is connected to the first main pipeline, and the first main oil outlet is connected to the upper vehicle oil supply pipeline. The first control component also includes a first control pipeline. The two ends of the first control pipeline are respectively connected to the first main pipeline and the first control oil chamber. The third valve body is disposed on the first control pipeline to control the opening and closing of the first main pipeline and the first control oil chamber and to adjust the position of the valve core to control the opening and closing of the first main oil inlet and the first main oil outlet.

[0006] In one optional embodiment, the first variable pumping assembly includes a first variable pump, a first feedback line, and a first one-way valve body. The inlet of the first feedback line is connected to the outrigger oil supply line, the auxiliary steering oil supply line, and the upper vehicle oil supply line. The outlet of the first feedback line is connected to the first feedback port of the first variable pump. The first one-way valve body is disposed on the first feedback line.

[0007] In one alternative implementation, a first filter element is connected in connection with the first main pipeline.

[0008] In one optional embodiment, the hydraulic drive system further includes: a second variable displacement pump assembly; a fourth valve body, connected to the second variable displacement pump assembly via a second main pipeline, the fourth valve body being connected to a main steering oil supply pipeline, the fourth valve body controlling the on / off connection between the second main pipeline and the main steering oil supply pipeline; and a second control assembly, one end of the second control assembly being connected to the second main pipeline, the other end of the second control assembly being connected to the upper vehicle oil supply pipeline, the second variable displacement pump assembly being selectively connected to the fourth valve body or the upper vehicle oil supply pipeline via the second control assembly.

[0009] In one optional embodiment, the second control component includes a fifth valve body and a sixth valve body. The fifth valve body has a second oil delivery chamber and a second control oil chamber formed by a valve core. The second main oil inlet and the second main oil outlet of the fifth valve body are both connected to the second oil delivery chamber. The second main oil inlet is connected to the second main pipeline, and the second main oil outlet is connected to the upper vehicle oil supply pipeline. The second control component also includes a second control pipeline. The two ends of the second control pipeline are respectively connected to the second main pipeline and the second control oil chamber. The sixth valve body is disposed on the second control pipeline to control the opening and closing of the second main pipeline and the second control oil chamber and to adjust the position of the valve core to control the opening and closing of the second main oil inlet and the second main oil outlet.

[0010] In one optional embodiment, the second variable pumping assembly includes a second variable pump, a second feedback line, and a second check valve body. The inlet of the second feedback line is connected to the main steering fuel supply line and the upper vehicle fuel supply line, and the outlet of the second feedback line is connected to the second feedback port of the second variable pump. The second check valve body is disposed on the second feedback line.

[0011] In one alternative implementation, a second filter element is connected in connection with the second main pipe.

[0012] In one alternative embodiment, the hydraulic drive system further includes a metering pump assembly.

[0013] Secondly, the present invention also provides an engineering machine, including the aforementioned hydraulic drive system.

[0014] The technical solution of this application has the following advantages:

[0015] The upper and lower vehicles share the first variable pump assembly, thereby reducing the need for a separate pump assembly, simplifying the overall structure of the hydraulic drive system, effectively controlling system costs, reducing space occupation on the vehicle body, and improving the space utilization rate of the construction machinery; furthermore, the first control assembly can selectively supply oil to the upper or lower vehicle, allowing the upper or lower vehicle to operate independently and ensuring driving safety. Attached Figure Description

[0016] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0017] Figure 1 This is a schematic diagram of the connection structure of a hydraulic drive system according to an embodiment of the present invention;

[0018] Figure 2 for Figure 1 A partially enlarged schematic diagram of a portion of the hydraulic drive system shown;

[0019] Figure 3 for Figure 1 A partially enlarged schematic diagram of another part of the hydraulic drive system shown.

[0020] Explanation of reference numerals in the attached figures:

[0021] 1. First variable pump assembly; 101. First variable pump; 102. First feedback line; 103. First check valve body; 104. Relief valve; 2. First valve body; 3. First main line; 4. Outrigger oil supply line; 5. Auxiliary steering oil supply line; 6. First control assembly; 601. Second valve body; 6011. First main oil inlet; 6012. First main oil outlet; 602. Third valve body; 603. First control line; 7. Upper vehicle oil supply line; 8. First filter element; 9. Second variable pump assembly; 901. Second variable pump; 902. Second feedback line; 903. Second one-way valve body; 10. Fourth valve body; 11. Second main line; 12. Main steering oil supply line; 13. Second control assembly; 1301. Fifth valve body; 13011. Second main oil inlet; 13012. Second main oil outlet; 1302. Sixth valve body; 1303. Second control line; 14. Second filter element; 15. Metering pump assembly; 16. Damping element. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0023] The following is combined with Figures 1 to 3 The following describes embodiments of the present invention.

[0024] According to an embodiment of the present invention, a hydraulic drive system is provided, comprising: a first variable displacement pump assembly 1; a first valve body 2, connected to the first variable displacement pump assembly 1 via a first main pipeline 3, the first valve body 2 being connected to a support leg oil supply pipeline 4 and an auxiliary steering oil supply pipeline 5, the first valve body 2 having a first working position and a second working position, in the first working position, the first valve body 2 being connected to the first main pipeline 3 and the support leg oil supply pipeline 4, and in the second working position, the first valve body 2 being connected to the first main pipeline 3 and the auxiliary steering oil supply pipeline 5; a first control assembly 6, one end of the first control assembly 6 being connected to the first main pipeline 3, and the other end of the first control assembly 6 being connected to an upper vehicle oil supply pipeline 7, the first variable displacement pump assembly 1 being selectively connected to the first valve body 2 or the upper vehicle oil supply pipeline 7 via the first control assembly 6.

[0025] The hydraulic drive system of this embodiment allows the lower vehicle and the upper vehicle to share the first variable pumping component 1, thereby reducing the setup of one pumping component, simplifying the overall structure of the hydraulic drive system, effectively controlling system cost, reducing space occupation on the vehicle body, and improving the space utilization rate of the construction machinery; furthermore, the first control component 6 can selectively supply oil to the upper vehicle or the lower vehicle, allowing the upper vehicle or the lower vehicle to operate independently, ensuring driving safety.

[0026] It is worth noting that when the first control component 6 is in the closed state, the first variable pump component 1 is connected to the first valve body 2 through the first main pipe 3. At this time, when the first valve body 2 is in the first working position, the first main pipe 3 is connected to the outrigger oil supply pipe 4, thereby providing power for the outrigger suspension action. When the first valve body 2 is in the second working position, the first main pipe 3 is connected to the auxiliary steering oil supply pipe 5, thereby providing power for the auxiliary steering action. When the first control component 6 is in the open state, the first variable pump component 1 is connected to the upper vehicle oil supply pipe 7 through the first control component 6, thereby providing power for the action of the upper vehicle's luffing mechanism, telescopic mechanism, etc.

[0027] In one embodiment, such as Figure 2 As shown, the first control component 6 includes a second valve body 601 and a third valve body 602. The second valve body 601 has a first oil supply chamber and a first control oil chamber separated by a valve core. The first main oil inlet 6011 and the first main oil outlet 6012 of the second valve body 601 are both connected to the first oil supply chamber. The first main oil inlet 6011 is connected to the first main pipeline 3, and the first main oil outlet 6012 is connected to the upper vehicle oil supply pipeline 7. Figure 2 As shown, the first control component 6 also includes a first control pipeline 603, the two ends of which are connected to the first main pipeline 3 and the first control oil chamber, respectively. The third valve body 602 is disposed on the first control pipeline 603 to control the opening and closing of the first main pipeline 3 and the first control oil chamber and to adjust the position of the valve core to control the opening and closing of the first main oil inlet 6011 and the first main oil outlet 6012.

[0028] Specifically, when it is necessary to supply oil to the undercarriage, that is, when the first control component 6 is in the closed state, the first control pipeline 603 connects the first main pipeline 3 and the first control oil chamber through the third valve body 602, so that both ends of the valve core of the second valve body 601 are subjected to pressure, thereby blocking the first main oil inlet 6011 and the first main oil outlet 6012, that is, the second valve body 601 is closed, and the first main pipeline 3 cannot supply oil to the undercarriage oil supply pipeline 7. When it is necessary to supply oil to the upper vehicle, that is, when the first control component 6 is in the open state, the third valve body 602 blocks the first control pipeline 603 to depressurize the first control oil chamber. The valve core of the second valve body 601 is subjected to pressure applied from one side of the first oil supply chamber, which causes the valve core of the second valve body 601 to move away so that the first main oil inlet 6011 and the first main oil outlet 6012 are connected. That is, the second valve body 601 is opened. At the same time, the first valve body 2 is closed, and the first main pipeline 3 cannot supply oil to the outrigger oil supply pipeline 4 and the auxiliary steering oil supply pipeline 5.

[0029] In this embodiment, as Figure 2 As shown, the first valve body 2 is a three-position four-way solenoid directional valve, the second valve body 601 is a two-way cartridge valve or a two-way logic valve, and the third valve body 602 is a two-position four-way solenoid directional valve.

[0030] Specifically, such as Figure 1 and Figure 2 As shown, when oil needs to be supplied to the outrigger oil supply line 4, the first variable pump assembly 1 outputs hydraulic oil to point P1. At this time, DT1 of the third valve body 602 is not energized, so the third valve body 602 works in the right position, so that the second valve body 601 is closed, and the hydraulic oil at point P1 cannot reach point B1. At the same time, DT3 of the first valve body 2 is energized, so the first valve body 2 works in the right position (i.e., the first working position), and the hydraulic oil at point P1 can be delivered to point A2.

[0031] Specifically, such as Figure 1 and Figure 2 As shown, when it is necessary to supply oil to the auxiliary steering oil supply line 5, the hydraulic oil output by the first variable pump assembly 1 reaches point P1. At this time, DT1 of the third valve body 602 is not energized, so that the third valve body 602 works in the right position, so that the second valve body 601 is closed, and the hydraulic oil at point P1 cannot reach point B1. At the same time, DT2 of the first valve body 2 is energized, so that the first valve body 2 works in the left position (that is, the second working position), and the hydraulic oil at point P1 can be delivered to point B2.

[0032] Specifically, such as Figure 1 and Figure 2As shown, when oil needs to be supplied to the upper vehicle oil supply line 7, the first variable pump assembly 1 outputs hydraulic oil to point P1. At this time, DT1 of the third valve body 602 is energized, causing the third valve body 602 to work in the left position, so that the second valve body 601 is opened, and the hydraulic oil at point P1 can be delivered to point B1. At the same time, the first valve body 2 is in the middle position, and the hydraulic oil at point P1 cannot reach points A2 and B2.

[0033] In one embodiment, such as Figure 1 and Figure 2 As shown, the first variable pump assembly 1 includes a first variable pump 101, a first feedback line 102, and a first check valve body 103. The inlet of the first feedback line 102 is connected to the outrigger oil supply line 4, the auxiliary steering oil supply line 5, and the upper vehicle oil supply line 7. The outlet of the first feedback line 102 is connected to the first feedback port of the first variable pump 101. The first check valve body 103 is mounted on the first feedback line 102. This configuration directs the higher pressure signals from the lower and upper vehicles to the first variable pump 101, enabling the first variable pump 101 to adaptively output oil of a corresponding displacement, thus achieving energy saving.

[0034] Specifically, the first variable pump 101 is a variable displacement piston pump, and the first one-way valve body 103 is a shuttle valve. One or more shuttle valves can be provided. The variable displacement piston pump is a load-sensitive pump. Its variable displacement is achieved by using the shuttle valve to guide high-pressure hydraulic oil through point LS1 to point X1 of the variable displacement piston pump, thereby realizing the adaptive adjustment of the variable displacement piston pump.

[0035] Furthermore, such as Figure 1 and Figure 2 As shown, the first feedback pipeline 102 is also connected to an overflow valve 104.

[0036] In one embodiment, such as Figure 1 and Figure 2 As shown, the auxiliary steering oil supply line 5 and the first feedback line 102 are also equipped with damping elements 16.

[0037] In one embodiment, such as Figure 1 As shown, a first filter element 8 is connected to the first main pipeline 3. Specifically, the first filter element 8 is a high-pressure filter.

[0038] In one embodiment, such as Figure 1 and Figure 3As shown, the hydraulic drive system also includes: a second variable pump assembly 9; a fourth valve body 10, which is connected to the second variable pump assembly 9 via a second main pipeline 11, and the fourth valve body 10 is connected to a main steering oil supply pipeline 12, and the fourth valve body 10 controls the on / off connection between the second main pipeline 11 and the main steering oil supply pipeline 12; and a second control assembly 13, one end of which is connected to the second main pipeline 11, and the other end of which is connected to the upper vehicle oil supply pipeline 7, and the second variable pump assembly 9 can be selectively connected to the fourth valve body 10 or the upper vehicle oil supply pipeline 7 via the second control assembly 13.

[0039] It is worth noting that when the second control component 13 is in the closed state, the second variable pump component 9 is connected to the fourth valve body 10 through the second main pipeline 11. At this time, when the fourth valve body 10 is in the working position, the second main pipeline 11 is connected to the main steering oil supply pipeline 12, thereby providing power for the main steering action. When the second control component 13 is in the open state, the second variable pump component 9 is connected to the upper vehicle oil supply pipeline 7 through the second control component 13, thereby providing power for the action of the upper vehicle's luffing mechanism, telescoping mechanism, etc.

[0040] In one embodiment, such as Figure 3 As shown, the second control component 13 includes a fifth valve body 1301 and a sixth valve body 1302. The fifth valve body 1301 has a second oil supply chamber and a second control oil chamber formed by a valve core. The second main oil inlet 13011 and the second main oil outlet 13012 of the fifth valve body 1301 are both connected to the second oil supply chamber. The second main oil inlet 13011 is connected to the second main pipeline 11, and the second main oil outlet 13012 is connected to the upper vehicle oil supply pipeline 7. Figure 3 As shown, the second control component 13 also includes a second control pipeline 1303. The two ends of the second control pipeline 1303 are respectively connected to the second main pipeline 11 and the second control oil chamber. The sixth valve body 1302 is disposed on the second control pipeline 1303 to control the opening and closing of the second main pipeline 11 and the second control oil chamber and to adjust the position of the valve core to control the opening and closing of the second main oil inlet 13011 and the second main oil outlet 13012.

[0041] Specifically, when it is necessary to supply oil to the undercarriage, that is, when the second control component 13 is in the closed state, the second control pipeline 1303 connects the second main pipeline 11 and the second control oil chamber through the sixth valve body 1302, so that both ends of the valve core of the fifth valve body 1301 are subjected to pressure, thereby blocking the second main oil inlet 13011 and the second main oil outlet 13012, that is, the fifth valve body 1301 is closed, and the second main pipeline 11 cannot supply oil to the undercarriage oil supply pipeline 7. When it is necessary to supply oil to the upper vehicle, that is, when the second control component 13 is in the open state, the sixth valve body 1302 blocks the second control pipeline 1303 to depressurize the second control oil chamber. The valve core of the fifth valve body 1301 is subjected to pressure applied from one side of the second oil supply chamber, thereby causing the valve core of the fifth valve body 1301 to move away so that the second main oil inlet 13011 and the second main oil outlet 13012 are connected. That is, the fifth valve body 1301 is opened. At the same time, the fourth valve body 10 is in the depressurized position, and the second main pipeline 11 cannot supply oil to the main steering oil supply pipeline 12.

[0042] In this embodiment, as Figure 3 As shown, the fourth valve body 10 is a two-position four-way solenoid directional valve, the fifth valve body 1301 is a two-way cartridge valve or a two-way logic valve, and the sixth valve body 1302 is a two-position four-way solenoid directional valve.

[0043] Specifically, such as Figure 1 and Figure 3 As shown, when oil needs to be supplied to the main steering oil supply line 12, the second variable pump assembly 9 outputs hydraulic oil to point P2. At this time, DT4 of the sixth valve body 1302 is not energized, so the sixth valve body 1302 works in the right position, so that the fifth valve body 1301 is closed, and the hydraulic oil at point P2 cannot reach point B1. At the same time, DT5 of the fourth valve body 10 is not energized, so the fourth valve body 10 works in the right position (i.e., the working position), and the hydraulic oil at point P2 can be delivered to point A1.

[0044] Specifically, such as Figure 1 and Figure 3 As shown, when oil needs to be supplied to the upper vehicle oil supply line 7, the second variable pump assembly 9 outputs hydraulic oil to point P2. At this time, DT4 of the sixth valve body 1302 is energized, causing the sixth valve body 1302 to work in the left position, so that the fifth valve body 1301 is opened, and the hydraulic oil at point P2 can be delivered to point B1. At the same time, the fourth valve body DT5 is energized, causing the fourth valve body 10 to work in the left position (i.e., the pressure relief position), and the hydraulic oil at point P2 cannot reach point A1.

[0045] In one embodiment, such as Figure 1 and Figure 3As shown, the second variable pump assembly 9 includes a second variable pump 901, a second feedback line 902, and a second check valve body 903. The inlet of the second feedback line 902 is connected to the main steering oil supply line 12 and the upper vehicle oil supply line 7, and the outlet of the second feedback line 902 is connected to the second feedback port of the second variable pump 901. The second check valve body 903 is mounted on the second feedback line 902. This configuration directs the higher pressure signals from the lower and upper vehicles to the second variable pump 901, enabling the second variable pump 901 to adaptively output oil of a corresponding displacement, thus achieving energy savings.

[0046] Specifically, the second variable pump 901 is a variable displacement piston pump, and the second one-way valve body 903 is a shuttle valve. One or more shuttle valves can be provided. The variable displacement piston pump is a load-sensitive pump. Its variable displacement is achieved by using the shuttle valve to guide high-pressure hydraulic oil through point LS2 to point X2 of the variable displacement piston pump, thus realizing the adaptive adjustment of the variable displacement piston pump.

[0047] In one embodiment, such as Figure 1 and Figure 3 As shown, damping elements 16 are also provided on the main steering oil supply line 12 and the second feedback line 902.

[0048] In one embodiment, such as Figure 1 As shown, a second filter element 14 is connected to the second main pipeline 11. Specifically, the second filter element 14 is a high-pressure filter.

[0049] In one embodiment, such as Figure 1 As shown, the hydraulic drive system also includes a fixed displacement pump assembly 15. The fixed displacement pump assembly 15 provides power for auxiliary actions such as the upper vehicle's rotation, the extension and retraction of the telescopic cylinder, the upper vehicle's air conditioning, and the counterweight. The fixed displacement pump assembly 15 may include one or more fixed displacement pumps.

[0050] According to an embodiment of the present invention, another aspect provides an engineering machine including the hydraulic drive system described above.

[0051] In this embodiment, the construction machinery is a single-engine crane. The lower cost of a single-engine crane allows for cost reduction in vehicle system components; the use of the hydraulic drive system in this embodiment further enables cost control in the single-engine crane.

[0052] Although embodiments of the invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the invention, and such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. A hydraulic drive system, characterized by, The hydraulic drive system comprises: a first variable pumping assembly (1); a first valve body (2) in communication with the first variable pumping assembly (1) through a first main pipeline (3), the first valve body (2) being in communication with a branch oil supply pipeline (4) and an auxiliary turning oil supply pipeline (5), the first valve body (2) having a first working position and a second working position, in the first working position, the first valve body (2) is in communication with the first main pipeline (3) and the branch oil supply pipeline (4), in the second working position, the first valve body (2) is in communication with the first main pipeline (3) and the auxiliary turning oil supply pipeline (5); a first control assembly (6), one end of the first control assembly (6) being in communication with the first main pipeline (3), the other end of the first control assembly (6) being in communication with an upper vehicle oil supply pipeline (7), the first variable pumping assembly (1) being selectively in communication with the first valve body (2) or the upper vehicle oil supply pipeline (7) through the first control assembly (6). The hydraulic drive system further comprises: a second variable pumping assembly (9); a fourth valve body (10) in communication with the second variable pumping assembly (9) through a second main pipeline (11), the fourth valve body (10) being in communication with a main turning oil supply pipeline (12), the fourth valve body (10) controlling the on-off of the second main pipeline (11) and the main turning oil supply pipeline (12); a second control assembly (13), one end of the second control assembly (13) being in communication with the second main pipeline (11), the other end of the second control assembly (13) being in communication with the upper vehicle oil supply pipeline (7), the second variable pumping assembly (9) being selectively in communication with the fourth valve body (10) or the upper vehicle oil supply pipeline (7) through the second control assembly (13).

2. The hydraulic drive system of claim 1, wherein, The first control assembly (6) comprises a second valve body (601) and a third valve body (602), the second valve body (601) being divided into a first oil supply cavity and a first control oil cavity by a spool, a first main oil inlet (6011) and a first main oil outlet (6012) of the second valve body (601) being in communication with the first oil supply cavity, the first main oil inlet (6011) being in communication with the first main pipeline (3), the first main oil outlet (6012) being in communication with the upper vehicle oil supply pipeline (7); The first control assembly (6) further comprises a first control pipeline (603), two ends of the first control pipeline (603) being in communication with the first main pipeline (3) and the first control oil cavity respectively, the third valve body (602) being arranged in the first control pipeline (603) to control the on-off of the first main pipeline (3) and the first control oil cavity and adjust the position of the spool to control the on-off of the first main oil inlet (6011) and the first main oil outlet (6012).

3. The hydraulic drive system of claim 1 or 2, wherein, The first variable pumping assembly (1) comprises a first variable pump (101), a first feedback pipeline (102) and a first one-way valve body (103), an inlet of the first feedback pipeline (102) is communicated with the branch oil supply pipeline (4), the auxiliary steering oil supply pipeline (5) and the vehicle body oil supply pipeline (7), an outlet of the first feedback pipeline (102) is communicated with a first feedback port of the first variable pump (101), and the first one-way valve body (103) is arranged on the first feedback pipeline (102).

4. The hydraulic drive system of claim 1 or 2, wherein, A first filter element (8) is arranged on the first main pipeline (3).

5. The hydraulic drive system of claim 1 or 2, wherein, The second control assembly (13) comprises a fifth valve body (1301) and a sixth valve body (1302), a second oil delivery cavity and a second control oil cavity are formed in the fifth valve body (1301) by a valve core, a second main oil inlet (13011) and a second main oil outlet (13012) of the fifth valve body (1301) are communicated with the second oil delivery cavity, the second main oil inlet (13011) is communicated with the second main pipeline (11), and the second main oil outlet (13012) is communicated with the vehicle body oil supply pipeline (7). The second control assembly (13) further comprises a second control pipeline (1303), two ends of the second control pipeline (1303) are respectively communicated with the second main pipeline (11) and the second control oil cavity, and the sixth valve body (1302) is arranged on the second control pipeline (1303) to control the on-off of the second main pipeline (11) and the second control oil cavity and adjust the position of the valve core to control the on-off of the second main oil inlet (13011) and the second main oil outlet (13012).

6. The hydraulic drive system of claim 1 or 2, wherein, The second variable pumping assembly (9) comprises a second variable pump (901), a second feedback pipeline (902) and a second one-way valve body (903), an inlet of the second feedback pipeline (902) is communicated with the main steering oil supply pipeline (12) and the vehicle body oil supply pipeline (7), an outlet of the second feedback pipeline (902) is communicated with a second feedback port of the second variable pump (901), and the second one-way valve body (903) is arranged on the second feedback pipeline (902).

7. The hydraulic drive system of claim 1 or 2, wherein, A second filter element (14) is arranged on the second main pipeline (11).

8. The hydraulic drive system of claim 1 or 2, wherein, The hydraulic drive system further comprises a constant pumping assembly (15).

9. A working machine, characterized in that The hydraulic drive system comprises any one of claims 1 to 8. The hydraulic drive system comprises any one of claims 1 to 8.

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