Hydraulic control system and loader

Abstract

The utility model belongs to the technical field of hydraulic systems, and discloses a hydraulic control system and a loader, the system comprises an oil tank, a pump unit, a working valve group, a pilot control valve group, a movable arm retaining valve and a rotating rod retaining valve, the oil inlet end of the pump unit is communicated with the oil tank, and the working valve group comprises a first movable arm reversing valve and a rotating rod reversing valve; the pump unit is communicated with an oil inlet of the first movable arm reversing valve and an oil inlet of the second reversing valve, two working oil ports of the first movable arm reversing valve are communicated with a rodless cavity and a rod cavity of the movable arm cylinder, two working oil ports of the second movable arm reversing valve are communicated with a rodless cavity and a rod cavity of the rotary rod cylinder, and the first movable arm reversing valve and the rotary rod reversing valve are reversed through the pilot control valve set. The movable arm holding valve and the rotating rod holding valve are used for preventing oil liquid in the rodless cavity from flowing back when the movable arm cylinder and the rotating rod cylinder bear loads. The loader comprises the hydraulic control system. The hydraulic control system can effectively prevent the movable arm from falling off and the rotating rod from releasing force, and ensures that the loading machine works reliably and effectively.

Description

TECHNICAL FIELD

[0001] The utility model relates to hydraulic system technical field especially relates to a kind of hydraulic control system and loader. BACKGROUND

[0002] The loader is provided with swing arm, rotating rod and other components, and the swing arm and the rotating rod are controlled by the hydraulic control system arranged inside.

[0003] In the related art, the hydraulic control system is generally provided with a swing arm reversing valve and a rotating rod reversing valve. The swing arm reversing valve and the rotating rod reversing valve are connected to a tank, a pump unit and other hydraulic components. The swing arm reversing valve is connected to a swing arm cylinder, and the swing arm cylinder is connected to the swing arm. The rotating rod reversing valve is connected to a rotating rod cylinder, and the rotating rod cylinder is connected to the rotating rod. The pump unit pumps oil from the tank, and the swing arm cylinder and the rotating rod cylinder are extended and retracted by switching the swing arm reversing valve and the rotating rod reversing valve to different positions, so as to control the movement of the swing arm and the rotating rod. In actual work, the hydraulic oil in the rodless cavity of the swing arm cylinder and the rotating rod cylinder bears the load received by the swing arm and the rotating rod. When the swing arm and the rotating rod receive a large instantaneous load, the hydraulic oil in the rodless cavity of the swing arm cylinder and the rotating rod cylinder may be reversely extruded, causing a temporary backflow of the hydraulic oil. This may cause the swing arm to drop and the rotating rod to lose force. In the long run, important hydraulic components such as the swing arm reversing valve and the rotating rod reversing valve may be damaged, affecting the reliability and stability of the loader. SUMMARY

[0004] The utility model aims at providing a hydraulic control system that can effectively prevent the backflow of oil in the rodless cavity of the swing arm cylinder and the rotating rod cylinder when they bear a load, prevent the accidental retraction of the piston rod of the swing arm cylinder and the rotating rod cylinder, and ensure the reliability and stability of the entire system when it bears a load.

[0005] To achieve this purpose, the utility model adopts the following technical solutions:

[0006] A hydraulic control system includes a tank, a pump unit, a working valve group, a pilot control valve group, a swing arm holding valve, a rotating rod holding valve, a swing arm cylinder, and a rotating rod cylinder. Among them,

[0007] The oil inlet end of the pump unit is communicated with the oil tank; the working valve group comprises a first boom reversing valve and a rotating rod reversing valve, the first boom reversing valve has an oil inlet a1, an oil outlet a2, a working oil outlet a3, a working oil outlet a4, a hydraulic control end e1 and a hydraulic control end e2, the rotating rod reversing valve has an oil inlet b1, an oil outlet b2, a working oil outlet b3, a working oil outlet b4, a hydraulic control end e3 and a hydraulic control end e4, the oil outlet end of the pump unit is communicated with the oil inlet a1 and the oil inlet b1, the oil outlet a2 and the oil outlet b2 are communicated with the oil tank, the working oil outlet a3 is communicated with the rodless cavity of the boom cylinder, the working oil outlet a4 is communicated with the rod cavity of the boom cylinder, the working oil outlet b3 is communicated with the rodless cavity of the rotating rod cylinder, and the working oil outlet b4 is communicated with the rod cavity of the rotating rod cylinder;

[0008] The hydraulic control end e1, the hydraulic control end e2, the hydraulic control end e3 and the hydraulic control end e4 can realize on-off control with the oil outlet end of the pump unit through the pilot control valve group; the boom holding valve is used for preventing the oil in the rodless cavity of the boom cylinder from flowing back to the working oil outlet a3 when the piston rod of the boom cylinder is extended and bears a load; and the rotating rod holding valve is used for preventing the oil in the rotating rod cylinder from flowing back to the working oil outlet b3 when the piston rod of the rotating rod cylinder is extended and bears a load.

[0009] Preferably, the boom holding valve comprises a first valve shell, a first valve core, a second valve core and a third valve core arranged in the first valve shell, the first valve shell has an oil port d1, an oil port d2, an oil port d3, an oil port d4, an oil port d5, an oil port d6, an oil port d7 and an oil port d8, the oil port d1 is communicated with the working oil outlet a3, the oil port d2 is communicated with the rodless cavity of the boom cylinder, the oil port d3 is communicated with the oil port d4, the oil port d5 is communicated with the working oil outlet a3, the oil port d6 is communicated with the oil port d7, and the oil port d8 is communicated with the pump unit; the first valve core is provided with a first throttling hole, one end of the first throttling hole is communicated with the oil port d1 and the oil port d2, and the other end of the first throttling hole is communicated with the oil port d3, the first valve core is used for conducting or cutting off the oil port d1 and the oil port d2, the second valve core is used for conducting or cutting off the side where the oil port d4 is located and the side where the oil port d5 and the oil port d6 are located, and the third valve core is used for controlling the on-off of the oil port d7 and the oil port d8; the third valve core has a hydraulic control end e6, and the pilot control valve group is used for controlling the on-off between the pump unit and the hydraulic control end e6.

[0010] As preferably, the rotating lever holding valve comprises a second valve housing and fourth, fifth and sixth valve spools arranged in the second valve housing, the second valve housing has oil port f1, oil port f2, oil port f3, oil port f4, oil port f5, oil port f6, oil port f7, oil port f8, the oil port f1 communicates with the working oil port b3, the oil port f2 communicates with the rodless chamber of the rotating lever cylinder, the oil port f3 communicates with the oil port f4, the oil port f5 communicates with the working oil port b3, the oil port f6 communicates with the oil port f7, the oil port f8 communicates with the pump unit; the fourth valve spool is provided with a second throttle hole, one end of the second throttle hole communicates with the oil port f1 and the oil port f2, and the other end communicates with the oil port f3, the fourth valve spool is used for conducting or cutting off the oil port f1 and the oil port f2, the fifth valve spool is used for conducting or cutting off the side where the oil port f4 is located and the side where the oil port f5 and the oil port f6 are located together, and the sixth valve spool is used for controlling the on-off of the oil port f7 and the oil port f8; the sixth valve spool has a liquid control end e7, and the pilot control valve group is used for controlling the on-off between the pump unit and the liquid control end e7.

[0011] As preferably, it is characterized in that it further comprises a supplement oil circuit, the supplement oil circuit comprises a supplement oil pipe, a first supplement oil overflow valve and a second supplement oil overflow valve; wherein,

[0012] The first end of the supplement oil pipe communicates with the pump unit, the second end of the supplement oil pipe communicates with the oil tank, the supplement oil pipe communicates with the oil inlet of the first supplement oil overflow valve and the oil inlet of the second supplement oil overflow valve, the oil outlet of the first supplement oil overflow valve communicates with the rodless chamber of the boom cylinder, and the oil outlet of the second supplement oil overflow valve communicates with the rodless chamber of the rotating lever cylinder.

[0013] As preferably, the supplement oil circuit further comprises a supplement oil floating valve, the supplement oil floating valve comprises a third valve housing, a seventh valve spool and an eighth valve spool, the third valve housing has oil port g1, oil port g2, oil port g3, oil port g4 and oil port g5, the oil port g1 communicates with the pipeline between the rod chamber of the boom cylinder and the oil port a4, the oil port g2 communicates with the supplement oil pipe, the oil port g3 communicates with the oil port g4, and the oil port g5 communicates with the oil tank; the seventh valve spool is provided with a third throttle hole, one end of the third throttle hole communicates with the oil port g1 and the oil port g2, and the other end communicates with the oil port g3, the seventh valve spool is used for conducting or cutting off the oil port g1 and the oil port g2, the eighth valve spool is used for controlling the on-off of the oil port g4 and the oil port g5, and the pilot control valve group is used for controlling the on-off between the pump unit and the liquid control end e8 of the eighth valve spool.

[0014] As preferably, the first boom reversing valve is a three-position four-way reversing valve; wherein,

[0015] When located at the intermediate position, the oil inlet a1, the oil outlet a2, the working oil port a3 and the working oil port a4 are not communicated with each other;

[0016] When located at the first working position, the oil inlet a1 is communicated with the working oil port a3, and the oil outlet a2 is communicated with the working oil port a4;

[0017] When located at the second working position, the oil inlet a1 is communicated with the working oil port a4, the oil outlet a2 is communicated with the working oil port a3, and the working oil port a4 is configured to unilaterally guide the oil inlet a1.

[0018] Preferably, the working valve group further comprises a second boom reversing valve having an oil inlet c1, an oil outlet c2, a working oil port c3 and a hydraulic control end e5, the oil outlet end of the pump unit is communicated with the oil inlet c1, the oil outlet c2 is communicated with the oil tank, and the working oil port c3 is communicated with the rodless cavity of the boom cylinder; the hydraulic control end e5 can be controlled by the pilot control valve group to control the on-off of the oil outlet end of the pump unit.

[0019] Preferably, a first check valve is arranged between the working oil port c3 and the rodless cavity of the boom cylinder, and the first check valve is configured to unilaterally guide the direction from the working oil port c3 to the rodless cavity of the boom cylinder.

[0020] Preferably, the pilot control valve group comprises a first pilot reversing valve, a second pilot reversing valve, a third pilot reversing valve, a fourth pilot reversing valve, a fifth pilot reversing valve and a controller; wherein,

[0021] The oil inlets of the first pilot reversing valve, the second pilot reversing valve, the third pilot reversing valve, the fourth pilot reversing valve and the fifth pilot reversing valve are communicated with the oil outlet end of the pump unit, the oil outlet of the first pilot reversing valve is communicated with the hydraulic control end e1, the oil outlet of the second pilot reversing valve is communicated with the hydraulic control end e2, the oil outlet of the third pilot reversing valve is communicated with the hydraulic control end e3, the oil outlet of the fourth pilot reversing valve is communicated with the hydraulic control end e4, and the oil outlet of the fifth pilot reversing valve is communicated with the hydraulic control end e5.

[0022] The controller is used to control the reversing of the first pilot reversing valve, the second pilot reversing valve, the third pilot reversing valve, the fourth pilot reversing valve and the fifth pilot reversing valve.

[0023] The utility model also provides a loader, including above-mentioned hydraulic control system, can effectively avoid boom cylinder and rotary lever cylinder when bearing load the oil liquid in the rod cavity appears backflow, prevents boom to drop arm and the condition of rotary lever force leakage to occur, ensures that the loader works reliable effective.

[0024] A loader, comprising the hydraulic control system of any one of the preceding claims, further comprising a machine body and a boom and a rotary lever provided on the machine body, the hydraulic control system being provided on the machine body, the boom being connected to a piston rod of the boom cylinder, and the rotary lever being connected to a piston rod of the rotary lever cylinder.

[0025] Advantages:

[0026] The utility model provides a hydraulic control system, boom keeps on valve in first boom reversing valve in the piston rod extension process of boom cylinder allows the oil liquid to flow by work oil port a3 to boom cylinder rod cavity, prevents the oil liquid in boom cylinder rod cavity to flow back to work oil port a3 when boom cylinder's piston rod extension and bearing load. Rotary lever keeps on valve in rotary lever reversing valve in the piston rod extension process of boom cylinder allows the oil liquid to flow by work oil port b3 to rotary lever cylinder rod cavity, prevents the oil liquid in rotary lever cylinder rod cavity to flow back to work oil port b3 when rotary lever cylinder's piston rod extension and bearing load. Boom keeps on valve with the setting of rotary lever keeps on valve, can effectively avoid boom cylinder and rotary lever cylinder when bearing load the oil liquid in the rod cavity appears backflow, prevents boom cylinder and rotary lever cylinder piston rod accidental retraction, ensures that the whole system can be reliable and stable when bearing load.

[0027] The utility model provides a loader, including above-mentioned hydraulic control system, can effectively avoid boom cylinder and rotary lever cylinder when bearing load the oil liquid in the rod cavity appears backflow, prevents boom to drop arm and the condition of rotary lever force leakage to occur, ensures that the loader works reliable effective. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 It is the hydraulic schematic diagram of the hydraulic control system provided by the utility model,

[0029] Figure 2 It is the hydraulic schematic diagram of boom keeps on valve provided by the utility model,

[0030] Figure 3 It is the partial structure schematic diagram of the hydraulic control system provided by the utility model,

[0031] Figure 4 It is the structure schematic diagram of boom keeps on valve release keeping provided by the utility model,

[0032] Figure 5 It is the hydraulic schematic diagram of rotary lever keeps on valve provided by the utility model,

[0033] Figure 6This is a partial structural schematic diagram of the hydraulic control system provided by this utility model;

[0034] Figure 7 This is a schematic diagram of the structure of the rotating rod retaining valve released from retaining provided by this utility model;

[0035] Figure 8 This is a hydraulic schematic diagram of the oil replenishment floating valve part provided by this utility model;

[0036] Figure 9 This is a schematic diagram of the structure of the oil replenishment floating valve provided by this utility model;

[0037] Figure 10 This is a schematic diagram of the first pilot directional valve provided by this utility model when it is not energized;

[0038] Figure 11 This is a schematic diagram of the energized first pilot directional valve provided by this utility model;

[0039] Figure 12 This is a schematic diagram of the second pilot directional valve and the fourth pilot directional valve provided by this utility model when they are not energized;

[0040] Figure 13 This is a schematic diagram of the energized structure of the second pilot directional valve and the fourth pilot directional valve provided by this utility model;

[0041] Figure 14 This is a schematic diagram of the main housing portion provided by this utility model;

[0042] Figure 15 This is a schematic diagram of the first pilot oil passage within the main housing provided by this utility model;

[0043] Figure 16 This is a schematic diagram of the second pilot oil passage within the main housing provided by this utility model;

[0044] Figure 17 This is a schematic diagram of the first return oil passage within the main housing provided by this utility model;

[0045] Figure 18 This is a schematic diagram of the second return oil passage within the main housing provided by this utility model;

[0046] Figure 19 This is a hydraulic schematic diagram of a hydraulic control system provided in another embodiment of the present invention.

[0047] In the picture:

[0048] 1. Fuel tank;

[0049] 2. Pump unit; 21. Main pump; 22. Pilot pump; 23. Flow regulating valve;

[0050] 31, first boom directional valve; 32, swing directional valve; 33, second boom directional valve; 34, first check valve;

[0051] 41, first pilot directional valve; 42, second pilot directional valve; 43, third pilot directional valve; 44, fourth pilot directional valve; 45, fifth pilot directional valve; 46, controller; 47, sixth pilot directional valve;

[0052] 5, boom holding valve; 501, first cavity; 5011, first sub-cavity; 5012, second sub-cavity; 502, second cavity; 5021, third sub-cavity; 5022, fourth sub-cavity; 51, first valve housing; 52, first spool; 521, first orifice; 522, first elastic member; 53, second spool; 531, second elastic member; 54, third spool;

[0053] 6, swing holding valve; 601, fourth cavity; 6011, fifth sub-cavity; 6012, sixth sub-cavity; 602, fifth cavity; 6021, seventh sub-cavity; 6022, eighth sub-cavity; 61, second valve housing; 62, fourth spool; 621, second orifice; 622, third elastic member; 63, fifth spool; 631, fourth elastic member; 64, sixth spool;

[0054] 71, boom cylinder; 72, swing cylinder;

[0055] 8, oil compensation pipe; 81, first oil compensation overflow valve; 82, second oil compensation overflow valve; 83, oil compensation floating valve; 831, third valve housing; 8311, seventh cavity; 83111, ninth sub-cavity; 83112, tenth sub-cavity; 832, seventh spool; 8321, third orifice; 8322, fifth elastic member; 833, eighth spool; 84, main overflow valve;

[0056] 9, main housing; 91, pilot oil port; 911, first pilot oil passage; 912, second pilot oil passage; 92, return oil port; 921, first return oil passage; 922, second return oil passage. DETAILED DESCRIPTION

[0057] The utility model will be explained in further detail below in combination with the drawings and embodiments. It can be understood that the specific embodiments described herein are only used to explain the utility model, and are not limited to the utility model. In addition, it should be noted that, in order to facilitate the description, only the part related to the utility model is shown in the drawings, not all structures.

[0058] In the description of the utility model, unless another definite provision and limitation, the term "link", "connection", "fix" should do broad sense understanding, for example, can be fixed connection, also can be detachable connection, or be integrated;Can be mechanical connection, also can be electrical connection;Can be directly connected, also can be indirectly connected through the intermediate medium, can be two elements internal communication or two element mutual action relationship.For the ordinary skill in the art, the specific meaning of the above-mentioned terms in the utility model can be understood according to the specific circumstances.

[0059] In the utility model, unless another definite provision and limitation, the first feature is "on" or "under" the second feature can include the first and second features direct contact, also can include the first and second features are not direct contact but contact through the additional features between them.Moreover, the first feature is "on", "above" and "on" the second feature includes the first feature is directly above and obliquely above the second feature, or just indicates that the first feature horizontal height is higher than the second feature.The first feature is "under", "below" and "under" the second feature includes the first feature is directly below and obliquely below the second feature, or just indicates that the first feature horizontal height is less than the second feature.

[0060] In the description of the embodiment, the term "on", "under", "right", etc. Orientation or position relationship is based on the orientation or position relationship shown in the drawing, only for the convenience of description and simplification operation, and does not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, therefore cannot be understood as a limitation on the utility model.In addition, the term "first", "second" is only used to distinguish in the description, and has no special meaning.

[0061] The embodiment provides a kind of hydraulic control system.Refer to Figures 1 to 18As shown, the hydraulic control system comprises an oil tank 1, a pump unit 2, a working valve group, a pilot control valve group, a boom holding valve 5, a swing holding valve 6, a boom cylinder 71 and a swing cylinder 72. The oil inlet of the pump unit 2 is communicated with the oil tank 1. The working valve group comprises a first boom directional valve 31 and a swing directional valve 32. The first boom directional valve 31 has an oil inlet a1, an oil outlet a2, a working oil outlet a3 and a working oil outlet a4. The swing directional valve 32 has an oil inlet b1, an oil outlet b2, a working oil outlet b3 and a working oil outlet b4. The oil outlet of the pump unit 2 is communicated with the oil inlets a1 and b1. The oil outlets a2 and b2 are communicated with the oil tank 1. The working oil outlet a3 is communicated with the rodless chamber of the boom cylinder 71. The working oil outlet a4 is communicated with the rod chamber of the boom cylinder 71. The working oil outlet b3 is communicated with the rodless chamber of the swing cylinder 72. The working oil outlet b4 is communicated with the rod chamber of the swing cylinder 72. The first boom directional valve 31 and the swing directional valve 32 are switched by the pilot control valve group. The boom holding valve 5 is used to prevent the oil in the rodless chamber of the boom cylinder 71 from flowing back to the working oil outlet a3 when the piston rod of the boom cylinder 71 is extended and bears a load. The swing holding valve 6 is used to prevent the oil in the rodless chamber of the swing cylinder 72 from flowing back to the working oil outlet b3 when the piston rod of the swing cylinder 72 is extended and bears a load.

[0062] In this embodiment, the boom holding valve 5 allows the oil to flow from the working oil outlet a3 to the rodless chamber of the boom cylinder 71 when the first boom directional valve 31 is switched during the extension of the piston rod of the boom cylinder 71, and prevents the oil in the rodless chamber of the boom cylinder 71 from flowing back to the working oil outlet a3 when the piston rod of the boom cylinder 71 is extended and bears a load. The swing holding valve 6 allows the oil to flow from the working oil outlet b3 to the rodless chamber of the swing cylinder 72 when the swing directional valve 32 is switched during the extension of the piston rod of the boom cylinder 71, and prevents the oil in the rodless chamber of the swing cylinder 72 from flowing back to the working oil outlet b3 when the piston rod of the swing cylinder 72 is extended and bears a load. The arrangement of the boom holding valve 5 and the swing holding valve 6 can effectively prevent the oil in the rodless chambers of the boom cylinder 71 and the swing cylinder 72 from flowing back when the system bears a load, prevent the piston rods of the boom cylinder 71 and the swing cylinder 72 from retracting unexpectedly, and ensure the reliability and stability of the system when it bears a load.

[0063] In this embodiment, with reference to Figures 2 to 4As shown, the boom holding valve 5 includes a first valve housing 51 and first, second and third valve spools 52, 53 and 54 arranged in the first valve housing 51, the first valve housing 51 having oil ports d1, d2, d3, d4, d5, d6, d7 and d8, the oil port d1 being communicated with the working oil port a3, the oil port d2 being communicated with the rodless chamber of the boom cylinder 71, the oil port d3 being communicated with the oil port d4, the oil port d5 being communicated with the working oil port a3, the oil port d6 being communicated with the oil port d7, and the oil port d8 being communicated with the pump unit 2; the first valve spool 52 is provided with a first throttling hole 521, one end of the first throttling hole 521 being communicated with the oil ports d1 and d2, and the other end being communicated with the oil port d3, the first valve spool 52 being used to open or shut off the oil ports d1 and d2, the second valve spool 53 being used to open or shut off the side where the oil port d4 is located and the common side where the oil ports d5 and d6 are located, and the third valve spool 54 being used to control the opening and closing of the oil ports d7 and d8. The third valve spool 54 has a hydraulic control end e6, and the pilot control valve group is used to control the opening and closing between the pump unit 2 and the hydraulic control end e6.

[0064] Specifically, the first valve housing 51 has a first cavity 501, a second cavity 502 and a third cavity, the first valve spool 52 slides in the first cavity 501 and divides the first cavity 501 into a first sub-cavity 5011 and a second sub-cavity 5012, the second valve spool 53 slides in the second cavity 502 and divides the second cavity 502 into a third sub-cavity 5021 and a fourth sub-cavity 5022, and the third valve spool 54 slides in the third cavity. The oil ports d1 and d2 are arranged in the first sub-cavity 5011, and the oil port d3 is arranged in the second sub-cavity 5012. The oil port d4 is arranged in the third sub-cavity 5021, and the oil ports d5 and d6 are arranged in the fourth sub-cavity 5022, the side where the oil port d4 is located being the third sub-cavity 5021, and the common side where the oil ports d5 and d6 are located being the fourth sub-cavity 5022. The oil ports d7 and d8 are arranged on opposite sides of the third cavity.

[0065] Specifically, when the piston rod of the boom cylinder 71 needs to be extended, the pilot control valve group controls the first boom reversing valve 31 to reverse, so that the oil inlet a1 of the first boom reversing valve 31 communicates with the working oil port a3, the pump set 2 pumps oil from the oil tank 1 and enters the rodless cavity of the boom cylinder 71 through the oil inlet a1, the working oil port a3, the oil port d1, the oil port d2 in turn, and then drives the piston rod of the boom cylinder 71 to extend. When the oil in the rodless cavity of the boom cylinder 71 is full, the oil entering the first sub-cavity 5011 through the working oil port d1 will enter the second sub-cavity 5012 through the first throttle hole 521, and then enter the third sub-cavity 5021 through the oil port d3 and the oil port d4, so that the second valve core 53 moves and cuts off the side where the oil port d4 is located and the side where the oil port d5 and the oil port d6 are located, that is, the communication between the third sub-cavity 5021 and the fourth sub-cavity 5022 is cut off. When the third cavity is also full of oil, the oil entering the second sub-cavity 5012 through the first throttle hole 521 will finally fill the second sub-cavity 5012 and push the first valve core 52 to move, so that the first valve core 52 tightly abuts against the inner cavity wall of the first sub-cavity 5011, cutting off the communication between the oil port d1 and the oil port d2, thereby preventing the oil in the rodless cavity of the boom cylinder 71 from flowing back to the working oil port a3, ensuring that the piston rod of the boom cylinder 71 can reliably and stably extend and bear load, and avoiding the piston rod of the boom cylinder 71 from retracting.

[0066] When the piston rod of the boom cylinder 71 needs to be retracted, i.e. the oil in the rodless cavity of the boom cylinder 71 needs to be discharged, the pilot control valve group controls the first boom directional valve 31 to switch, so that the oil outlet a2 of the first boom directional valve 31 communicates with the working oil port a3, and the pilot control valve group turns on the oil path between the pump set 2 and the hydraulic control end e6, so that the pump set 2 provides pilot oil to the hydraulic control end e6 to push the third valve core 54 to move, so that the oil port d7 and the oil port d8 are communicated, and the pump set 2 provides oil to the oil port d8, and then enters the fourth sub-cavity 5022 through the oil port d8, the oil port d7 and the oil port d6, and pushes the second valve core 53 to move in the opposite direction, so that the second valve core 53 releases the cut-off of the side where the oil port d4 is located and the common side of the oil port d5 and the oil port d6, i.e. the third sub-cavity 5021 and the fourth sub-cavity 5022 are reconnected. In this way, the oil in the second sub-cavity 5012 can enter the working oil port a3 through the oil port d3, the oil port d4 and the oil port d5 in sequence, so that this part of oil finally returns to the oil tank 1, and at this time the second sub-cavity 5012 is a low pressure area. Due to the action of the first throttle hole 521, the oil in the first sub-cavity 5011 cannot quickly reach the second sub-cavity 5012, i.e. the first sub-cavity 5011 is a high pressure area in a short time, and the pressure difference will push the first valve core 52 to move towards the side where the second sub-cavity 5012 is located, so that the oil port d1 and the oil port d2 are reconnected, and then the oil in the rodless cavity of the boom cylinder 71 can quickly flow through the oil port d2, the oil port d1, the working oil port d3 and the oil outlet a2 to return to the oil tank 1, so as to realize the retraction of the piston rod of the boom cylinder 71 and realize effective oil discharge.

[0067] Further specifically, the second sub-cavity 5012 is provided with a first elastic member 522, one end of the first elastic member 522 abuts against the first valve core 52, and the other end abuts against the inner wall of the second sub-cavity 5012. The first elastic member 522 is adapted to provide a force for forcing the first valve core 52 to move towards the direction of cutting off the oil port d1 and the oil port d2, i.e. the first elastic member 522 provides a force for cutting off the first sub-cavity 5011 and the second sub-cavity 5012.

[0068] Further specifically, the third sub-cavity 5021 is provided with a second elastic member 531, one end of the second elastic member 531 abuts against the inner wall of the third sub-cavity 5021, and the other end abuts against the second valve core 53. The second elastic member 531 is adapted to provide a force for forcing the second valve core 53 to move towards the side where the oil port d4 is located and the common side of the oil port d5 and the oil port d6, i.e. the second elastic member 531 provides a force for cutting off the third sub-cavity 5021 and the fourth sub-cavity 5022.

[0069] Exemplarily, the first elastic member 522 and the second elastic member 531 are both springs.

[0070] In this embodiment, with reference to Figures 5 to 7As shown, the rotating rod holding valve 6 comprises a second valve housing 61 and fourth, fifth and sixth valve spools 62, 63 and 64 arranged in the second valve housing 61. The second valve housing 61 has oil ports f1, f2, f3, f4, f5, f6, f7 and f8, the oil port f1 is communicated with the working oil port b3, the oil port f2 is communicated with the rodless chamber of the rotating rod cylinder 72, the oil port f3 is communicated with the oil port f4, the oil port f5 is communicated with the working oil port b3, the oil port f6 is communicated with the oil port f7, and the oil port f8 is communicated with the pump unit 2. The fourth valve spool 62 is provided with a second throttle hole 621, one end of the second throttle hole 621 is communicated with the oil ports f1 and f2, and the other end is communicated with the oil port f3. The fourth valve spool 62 is used to open or cut off the oil ports f1 and f2. The fifth valve spool 63 is used to open or cut off the side where the oil port f4 is located and the common side where the oil ports f5 and f6 are located. The sixth valve spool 64 is used to control the opening and closing of the oil ports f7 and f8. The sixth valve spool 64 has a pilot control end e7, and the pilot control valve group is used to control the opening and closing between the pump unit 2 and the pilot control end e7.

[0071] Specifically, the second valve housing 61 has a fourth cavity 601, a fifth cavity 602 and a sixth cavity. The fourth valve spool 62 slides in the fourth cavity 601 and divides the fourth cavity 601 into a fifth sub-cavity 6011 and a sixth sub-cavity 6012. The fifth valve spool 63 slides in the fifth cavity 602 and divides the fifth cavity 602 into a seventh sub-cavity 6021 and an eighth sub-cavity 6022. The sixth valve spool 64 slides in the sixth cavity. The oil ports f1 and f2 are arranged in the fifth sub-cavity 6011, and the oil port f3 is arranged in the sixth sub-cavity 6012. The oil port f4 is arranged in the seventh sub-cavity 6021, and the oil ports f5 and f6 are arranged in the eighth sub-cavity 6022. The side where the oil port f4 is located is the seventh sub-cavity 6021, and the common side where the oil ports f5 and f6 are located is the eighth sub-cavity 6022. The oil ports f7 and f8 are arranged on opposite sides of the sixth cavity.

[0072] Specifically, when the piston rod of the rotating rod cylinder 72 needs to be extended, the pilot control valve group controls the rotating rod reversing valve 32 to reverse, so that the oil inlet b1 of the rotating rod reversing valve 32 is communicated with the working oil port b3. The pump unit 2 pumps oil from the oil tank 1 and enters the rodless cavity of the rotating rod cylinder 72 through the oil inlet b1, the working oil port b3, the oil port f1 and the oil port f2 in sequence, thereby driving the piston rod of the rotating rod cylinder 72 to extend. When the oil in the rodless cavity of the rotating rod cylinder 72 is full, the oil entering the fifth sub-cavity 6011 through the working oil port f1 enters the sixth sub-cavity 6012 through the second throttle hole 621, and then enters the seventh sub-cavity 6021 through the oil port f3 and the oil port f4, so that the fifth valve core 63 moves and cuts off the side where the oil port f4 is located and the side where the oil ports f5 and f6 are located, that is, the communication between the seventh sub-cavity 6021 and the eighth sub-cavity 6022 is cut off. When the sixth cavity is also full of oil, the oil entering the sixth sub-cavity 6012 through the second throttle hole 621 will eventually fill the sixth sub-cavity 6012, and push the fourth valve core 62 to move, so that the fourth valve core 62 tightly abuts against the inner cavity wall of the fifth sub-cavity 6011, and the communication between the oil port f1 and the oil port f2 is cut off, thereby preventing the oil in the rodless cavity of the rotating rod cylinder 72 from flowing back to the working oil port b3, ensuring that the piston rod of the rotating rod cylinder 72 can reliably and stably extend and bear load, and avoiding the piston rod of the rotating rod cylinder 72 from retracting.

[0073] When the piston rod of the rotating rod cylinder 72 needs to be retracted, that is, the oil in the rodless cavity of the rotating rod cylinder 72 needs to be discharged, the pilot control valve group controls the rotating rod reversing valve 32 to reverse, so that the oil outlet b2 of the rotating rod reversing valve 32 is communicated with the working oil port b3. The pilot control valve group communicates the oil path between the pump unit 2 and the hydraulic control end e7, so that the pump unit 2 provides pilot oil to the hydraulic control end e7 to push the sixth valve core 64 to move, so that the oil port f7 is communicated with the oil port f8. The pump unit 2 provides oil to the oil port f8, and the oil enters the eighth sub-cavity 6022 through the oil port f8, the oil port f7 and the oil port f6 in sequence, pushes the fifth valve core 63 to move in the opposite direction, so that the fifth valve core 63 is unblocked on the side where the oil port f4 is located and the side where the oil ports f5 and f6 are located, that is, the seventh sub-cavity 6021 and the eighth sub-cavity 6022 are reconnected. In this way, the oil in the fifth sub-cavity 6011 can enter the working oil port b3 through the oil port f3, the oil port f4 and the oil port f5 in sequence, so that the oil finally returns to the oil tank 1, and the sixth sub-cavity 6012 is a low-pressure area at this time. Due to the action of the second throttle hole 621, the oil in the fifth sub-cavity 6011 cannot quickly reach the sixth sub-cavity 6012, that is, the fifth sub-cavity 6011 is a high-pressure area in a short time, and the pressure difference pushes the fourth valve core 62 to move towards the side where the sixth sub-cavity 6012 is located, so that the oil port f1 and the oil port f2 are reconnected, and then the oil in the rodless cavity of the rotating rod cylinder 72 can quickly flow through the oil port f2, the oil port f1, the working oil port f3 and the oil outlet b2 to return to the oil tank 1, thereby achieving the retraction of the piston rod of the rotating rod cylinder 72 and effectively discharging the oil.

[0074] Further specifically, the third elastic member 622 is arranged in the sixth sub-cavity 6012, one end of the third elastic member 622 abuts against the fourth valve core 62, and the other end of the third elastic member 622 abuts against the inner wall of the sixth sub-cavity 6012. The third elastic member 622 is adapted to provide a force for forcing the fourth valve core 62 to move towards the direction of the cut-off oil port f1 and the oil port f2, i.e. the third elastic member 622 provides a force for forcing the cut-off of the fifth sub-cavity 6011 and the sixth sub-cavity 6012.

[0075] Further specifically, the fourth elastic member 631 is arranged in the seventh sub-cavity 6021, one end of the fourth elastic member 631 abuts against the inner wall of the seventh sub-cavity 6021, and the other end of the fourth elastic member 631 abuts against the fifth valve core 63. The fourth elastic member 631 is adapted to provide a force for forcing the fifth valve core 63 to move towards the direction of the side where the cut-off oil port f4 is located and the side where the oil ports f5 and f6 are located, i.e. the fourth elastic member 631 provides a force for forcing the cut-off of the seventh sub-cavity 6021 and the eighth sub-cavity 6022.

[0076] Exemplarily, the third elastic member 622 and the fourth elastic member 631 are both springs.

[0077] In the embodiment, the number of the boom cylinders 71 is set to be at least two, and the rodless cavities of the at least two boom cylinders 71 are communicated with each other. For a conventional loader, the number of the boom cylinders 71 is set to be two. The rodless cavities of the two boom cylinders 71 are communicated with each other, so as to ensure that the pressures in the rodless cavities of the two boom cylinders 71 are equal, and there is no pressure difference.

[0078] In the embodiment, the hydraulic control system further comprises a make-up oil circuit, which comprises a make-up pipe 8, a first make-up overflow valve 81 and a second make-up overflow valve 82. The first end of the make-up pipe 8 is communicated with the pump set 2, the second end of the make-up pipe 8 is communicated with the tank 1, the make-up pipe 8 is communicated with the oil inlet of the first make-up overflow valve 81 and the oil inlet of the second make-up overflow valve 82, the oil outlet of the first make-up overflow valve 81 is communicated with the rodless cavity of the boom cylinder 71, and the oil outlet of the second make-up overflow valve 82 is communicated with the rodless cavity of the swing cylinder 72. Specifically, the first make-up overflow valve 81 and the second make-up overflow valve 82 are arranged,

[0079] When the oil pressure in the rodless cavities of the boom cylinder 71 and the swing cylinder 72 exceeds the preset pressure, overflow pressure relief is performed to protect the related parts in the oil circuit. In addition, when the pressure in the rodless cavities of the boom cylinder 71 and the swing cylinder 72 approaches the vacuum, the first make-up overflow valve 81 and the second make-up overflow valve 82 can respectively quickly make up oil for the rodless cavities of the boom cylinder 71 and the swing cylinder 72.

[0080] In this embodiment, a main relief valve 84 is connected to the oil replenishment pipe 8. The main relief valve 84 is provided to protect the oil pressure in the oil replenishment pipe 8 and prevent the pressure from being too high and exceeding the threshold.

[0081] Furthermore, referring to Figures 8 to 9 As shown, the replenishing oil circuit also includes a replenishing floating valve 83, which includes a third valve body 831, a seventh valve core 832, and an eighth valve core 833. The third valve body 831 has oil ports g1, g2, g3, g4, and g5. Oil port g1 is connected to the pipeline between the rod chamber of the boom cylinder 71 and oil port a4. Oil port g2 is connected to the replenishing oil pipe 8, oil port g3 is connected to oil port g4, and oil port g5 is connected to the oil tank 1. The seventh valve core 832 is provided with a third throttling orifice 8321. One end of the third throttling orifice 8321 is connected to oil ports g1 and g2, and the other end is connected to oil port g3. The seventh valve core 832 is used to open or close oil ports g1 and g2, and the eighth valve core 833 is used to control the opening and closing of oil ports g4 and g5. The pilot control valve group is used to control the opening and closing between the pump unit 2 and the hydraulic control terminal e8.

[0082] Specifically, the third valve housing 831 has a seventh chamber 8311 and an eighth chamber. The seventh valve core 832 slides in the seventh chamber and divides the seventh chamber 8311 into a ninth sub-chamber 83111 and a tenth sub-chamber 83112. The eighth valve core 833 slides in the eighth chamber. Oil ports g1 and g2 are located in the ninth sub-chamber 83111, oil port g3 is located in the tenth sub-chamber 83112, and oil ports g4 and g5 are located on opposite sides of the eighth chamber.

[0083] Specifically, the oil flows from the first end to the second end of the inner oil supply pipe 8. When it is necessary to replenish the rod chamber of the boom cylinder 71 with oil, the oil in the oil supply pipe 8 enters the ninth sub-chamber 83111 through the working oil port g2, and then enters the rod chamber of the boom cylinder 71 through the oil port g1. Furthermore, the oil entering the ninth sub-chamber 83111 enters the tenth sub-chamber 83112 through the third throttle orifice 8321. Since the oil ports g4 and g5 are disconnected at this time, the tenth sub-chamber 83112 gradually fills with oil, pushing the seventh valve core 832 to move, and finally causing the seventh valve core 832 to press tightly against the inner wall of the ninth sub-chamber 83111, cutting off the connection between the oil ports g1 and g2.

[0084] When the pilot control valve group is turned on to connect the pump unit 2 and the eighth spool 833, the eighth valve is moved to switch direction, and the oil port g4 is connected with the oil port g5, so that the oil in the tenth cavity 83112 can flow back to the tank 1 through the oil port g3, the oil port g4 and the oil port g5 in turn. At this time, the tenth cavity 83112 is a low-pressure area. Due to the effect of the third throttle hole 8321, the oil in the ninth cavity 83111 cannot quickly reach the tenth cavity 83112, that is, the ninth cavity 83111 is a high-pressure area in a short time. The pressure difference drives the seventh spool 832 to move to the side where the tenth cavity 83112 is located, so that the oil port g1 and the oil port g2 are reconnected, and then the oil in the rod cavity of the boom cylinder 71 can flow back to the tank 1 through the oil port g1 and the oil port g2, realizing the communication between the rod cavity of the boom cylinder 71 and the tank 1, thereby realizing the floating function of the boom cylinder 71.

[0085] Further specifically, the tenth cavity 83112 is provided with a fifth elastic member 8322, one end of the fifth elastic member 8322 abuts against the seventh spool 832, and the other end abuts against the inner wall of the tenth cavity 83112. The fifth elastic member 8322 is adapted to provide a force for driving the seventh spool 832 to move in a direction of cutting off the oil port g1 and the oil port g2, that is, the first elastic member 522 provides a force for cutting off the ninth cavity 83111 and the tenth cavity 83112.

[0086] Exemplarily, the fifth elastic member 8322 is a spring.

[0087] In the embodiment, the first valve housing 51, the second valve housing 61 and the third valve housing 831 are fixedly arranged on the main housing 9.

[0088] In the embodiment, the first boom directional valve 31 is a three-position four-way directional valve. When in the middle position, the inlet port a1, the outlet port a2, the working oil port a3 and the working oil port a4 are not connected with each other; when in the first working position, the inlet port a1 is connected with the working oil port a3, and the outlet port a2 is connected with the working oil port a4; when in the second working position, the inlet port a1 is connected with the working oil port a4, and the outlet port a2 is connected with the working oil port a3, and the working oil port a4 is configured to unidirectionally connect the inlet port a1.

[0089] Specifically, the spool of the first boom directional valve 31 is provided with a second check valve in the third working position, and the second check valve is configured to unidirectionally connect from the working oil port a4 to the inlet port a1.

[0090] Specifically, when the second working position of the first swing boom directional valve 31 is in the working position, a part of the oil in the rodless chamber of the swing boom cylinder 71 can be supplemented into the rod chamber of the swing boom cylinder 71 through the working oil port a3, the oil inlet a1 and the working oil port a4, so that the rod chamber of the swing boom cylinder 71 can be supplemented with oil, the effective retraction of the piston rod of the swing boom cylinder 71 is ensured, and no additional oil is consumed, saving energy consumption.

[0091] Further, the working valve group further comprises a second swing boom directional valve 33, the second swing boom directional valve 33 has an oil inlet c1, an oil outlet c2 and a working oil port c3, the oil outlet end of the pump unit 2 is communicated with the oil inlet c1, the oil outlet c2 is communicated with the oil tank 1, and the working oil port c3 is communicated with the rodless chamber of the swing boom cylinder 71; the second swing boom directional valve 33 is realized by the pilot control valve group. By arranging the second swing boom directional valve 33, the second swing boom directional valve 33 can work together with the first swing boom directional valve 31 to supply oil to the rodless chamber of the swing boom cylinder 71, and the extension action of the piston rod of the swing boom cylinder 71 is accelerated.

[0092] Specifically, the first one-way valve 34 is arranged between the working oil port c3 and the rodless chamber of the swing boom cylinder 71, and the first one-way valve 34 is configured to be unidirectional from the working oil port c3 to the rodless chamber of the swing boom cylinder 71. By arranging the first one-way valve 34, the backflow of the oil in the rodless chamber of the swing boom cylinder 71 towards the working oil port c3 can be effectively prevented.

[0093] In the embodiment, the first swing boom directional valve 31 has a hydraulic control end e1 and a hydraulic control end e2, the swing boom directional valve 32 has a hydraulic control end e3 and a hydraulic control end e4, and the second swing boom directional valve 33 has a hydraulic control end e5. The pilot control valve group comprises a first pilot directional valve 41, a second pilot directional valve 42, a third pilot directional valve 43, a fourth pilot directional valve 44, a fifth pilot directional valve 45 and a controller 46. Among them,

[0094] The oil inlets of the first pilot directional valve 41, the second pilot directional valve 42, the third pilot directional valve 43, the fourth pilot directional valve 44 and the fifth pilot directional valve 45 are all communicated with the oil outlet end of the pump unit 2, the oil outlet of the first pilot directional valve 41 is communicated with the hydraulic control end e1, the oil outlet of the second pilot directional valve 42 is communicated with the hydraulic control end e2, the oil outlet of the third pilot directional valve 43 is communicated with the hydraulic control end e3, the oil outlet of the fourth pilot directional valve 44 is communicated with the hydraulic control end e4, and the oil outlet of the fifth pilot directional valve 45 is communicated with the hydraulic control end e5. The controller 46 is used to control the directional change of the first pilot directional valve 41, the second pilot directional valve 42, the third pilot directional valve 43, the fourth pilot directional valve 44 and the fifth pilot directional valve 45.

[0095] Specifically, the control end of the first pilot directional control valve 41, the control end of the second pilot directional control valve 42, the control end of the third pilot directional control valve 43, the control end of the fourth pilot directional control valve 44, and the control end of the fifth pilot directional control valve 45 are all provided with electromagnets, that is, the control end of the first pilot directional control valve 41, the control end of the second pilot directional control valve 42, the control end of the third pilot directional control valve 43, the control end of the fourth pilot directional control valve 44, and the fifth pilot directional control valve 45 are all set as electromagnetic directional control valves, and the controller 46 controls the on-off of the electromagnets of the corresponding hydraulic control end to make the corresponding hydraulic control end have magnetism, thereby realizing the electromagnetic directional control function.

[0096] Optionally, the controller 46 is a PCB circuit board.

[0097] Specifically, the hydraulic control end e6 of the third spool 54 is in communication with the oil outlet of the second pilot directional control valve 42, the hydraulic control end e7 of the sixth spool 64 is in communication with the oil outlet of the fourth pilot directional control valve 44, and the hydraulic control end e8 of the eighth spool 833 is in communication with the oil outlet of the second pilot directional control valve 42.

[0098] Exemplarily, Figures 10 to 11 A specific structure diagram of the first pilot directional control valve 41 is provided. Among them Figure 10 is a structure diagram of the first pilot directional control valve 41 without power supply, Figure 11 is a structure diagram of the first pilot directional control valve 41 with power supply. It is worth mentioning that the structure diagrams of the third pilot directional control valve 43 and the fifth pilot directional control valve 45 are the same as the arrangement of the first pilot directional control valve 41.

[0099] Exemplarily, Figures 12 to 13 A specific structure diagram of the second pilot directional control valve 42 and the fourth pilot directional control valve 44 is provided. Among them Figure 12 is a structure diagram of the second pilot directional control valve 42 and the fourth pilot directional control valve 44 without power supply; Figure 13 is a structure diagram of the second pilot directional control valve 42 and the fourth pilot directional control valve 44 with power supply.

[0100] Exemplarily, Figure 14 A schematic diagram of the main housing 9 is provided. The main housing 9 is provided with a pilot oil port 91 and a return oil port 92. Among them, the pilot oil port 91 is in communication with the pump unit 2, and the return oil port 92 is in communication with the oil tank 1.

[0101] Exemplarily, Figures 15 to 16Provided is a schematic view of the first pilot oil passage 911 and the second pilot oil passage 912 in the main housing 9. Specifically, the first pilot oil passage 911 and the second pilot oil passage 912 are in communication with the pump set 2 at the first end, the second end of the first pilot oil passage 911 is in communication with the oil inlet of the first pilot directional valve 41, the oil inlet of the third pilot directional valve 43, and the oil inlet of the fifth pilot directional valve 45, and the second end of the second pilot oil passage 912 is in communication with the oil inlet of the second pilot directional valve 42 and the oil inlet of the fourth pilot directional valve 44. The first pilot oil passage 911 and the second pilot oil passage 912 are both arranged inside the main housing 9, which can reduce the arrangement of external pipelines, reduce costs, and simplify the structure.

[0102] Exemplarily, Figures 17 to 18 Provided is a schematic view of the first return oil passage 921 and the second return oil passage 922 in the main housing 9. Specifically, the first return oil passage 921 and the second return oil passage 922 are in communication with the oil tank 1 at the first end, the second end of the first return oil passage 921 is in communication with the oil outlet of the first pilot directional valve 41, the oil outlet of the third pilot directional valve 43, and the oil outlet of the fifth pilot directional valve 45, and the second end of the second return oil passage 912 is in communication with the oil outlet of the second pilot directional valve 42 and the oil outlet of the fourth pilot directional valve 44. The first return oil passage 921 and the second return oil passage 922 are both arranged inside the main housing 9, which can reduce the arrangement of external pipelines, reduce costs, and simplify the structure.

[0103] In some other optional embodiments, with reference to Figure 19 as shown, Figure 19 the working oil port c3 and the working oil port c4 of the second boom directional valve 33 are not connected to the boom cylinder 71. The second boom directional valve 33 can be used to connect other components on the loader, so that the loader can be adapted for differential customization, for example, to realize side dumping, wood clamping, quick change function, and increase practicability.

[0104] Specifically, in Figure 19 the sixth pilot control valve is also used to control the hydraulic control end e9 of the second boom directional valve 33. The oil inlet of the sixth pilot directional valve 47 is in communication with the oil outlet of the pump set 2, and the oil outlet of the sixth pilot directional valve 47 is in communication with the hydraulic control end e9. The controller 46 is used to control the directional change of the sixth pilot directional valve 47. The sixth pilot directional valve 47 is an electromagnetic directional valve

[0105] In the present embodiment, the pump set 2 includes two main pumps 21 and one pilot pump 22. Each main pump 21 is correspondingly provided with a flow regulating valve 23. Specifically, the oil inlet of the flow regulating valve 23 is in communication with the oil tank 1, and the oil outlet of the flow regulating valve 23 is in communication with the oil inlet of the main pump 21. By arranging the flow regulating valve 23, the flow of the main pump 21 can be correspondingly adjusted.

[0106] The embodiment also provides a loader. The loader comprises the hydraulic control system, a machine body, a boom and a swing arm provided on the machine body, and the hydraulic control system is provided on the machine body, the boom is connected to a piston rod of the boom cylinder 71, and the swing arm is connected to a piston rod of the swing arm cylinder 72.

[0107] The loader provided by the utility model avoids the backflow of oil in the rodless cavity of the boom cylinder 71 and the swing arm cylinder 72 when the boom cylinder 71 and the swing arm cylinder 72 bear loads, prevents the boom from falling and the swing arm from leaking force, and ensures that the loader works reliably and effectively.

[0108] Obviously, the above embodiment of the utility model is only an example for clearly illustrating the utility model, and is not a limitation on the implementation mode of the utility model. For ordinary skilled persons in the art, various obvious changes, re-adjustments and replacements can be made without departing from the protection scope of the utility model. It is unnecessary and impossible to enumerate all the implementation modes. Any modification, equivalent replacement and improvement within the spirit and principle of the utility model should be included in the protection scope of the utility model claim.

Claims

1. A hydraulic control system characterized by, The hydraulic system comprises an oil tank (1), a pump unit (2), a working valve group, a pilot control valve group, a boom holding valve (5), a swing holding valve (6), a boom cylinder (71) and a swing cylinder (72); wherein, The oil inlet end of the pump unit (2) is communicated with the oil tank (1); the working valve group comprises a first boom reversing valve (31) and a swing reversing valve (32), the first boom reversing valve (31) has an oil inlet a1, an oil outlet a2, a working oil outlet a3 and a working oil outlet a4, the swing reversing valve (32) has an oil inlet b1, an oil outlet b2, a working oil outlet b3 and a working oil outlet b4, the oil outlet end of the pump unit (2) is communicated with the oil inlets a1 and b1, the oil outlets a2 and b2 are communicated with the oil tank (1), the working oil outlet a3 is communicated with the rodless cavity of the boom cylinder (71), the working oil outlet a4 is communicated with the rod cavity of the boom cylinder (71), the working oil outlet b3 is communicated with the rodless cavity of the swing cylinder (72), and the working oil outlet b4 is communicated with the rod cavity of the swing cylinder (72); The first boom reversing valve (31) and the swing reversing valve (32) are reversed by the pilot control valve group; the boom holding valve (5) is used to prevent the oil in the rodless cavity of the boom cylinder (71) from flowing back to the working oil outlet a3 when the piston rod of the boom cylinder (71) is extended and bears a load; and the swing holding valve (6) is used to prevent the oil in the swing cylinder (72) from flowing back to the working oil outlet b3 when the piston rod of the swing cylinder (72) is extended and bears a load.

2. The hydraulic control system of claim 1, wherein, The boom holding valve (5) comprises a first valve shell (51) and a first valve core (52), a second valve core (53) and a third valve core (54) arranged in the first valve shell (51), the first valve shell (51) has an oil port d1, an oil port d2, an oil port d3, an oil port d4, an oil port d5, an oil port d6, an oil port d7, an oil port d8, the oil port d1 is communicated with the working oil outlet a3, the oil port d2 is communicated with the rodless cavity of the boom cylinder (71), the oil port d3 is communicated with the oil port d4, the oil port d5 is communicated with the working oil outlet a3, the oil port d6 is communicated with the oil port d7, the oil port d8 is communicated with the pump unit (2); the first valve core (52) is provided with a first throttling hole (521), one end of the first throttling hole (521) is communicated with the oil ports d1 and d2, and the other end is communicated with the oil port d3, the first valve core (52) is used to conduct or cut off the oil ports d1 and d2, the second valve core (53) is used to conduct or cut off the oil port d4 and the common side of the oil ports d5 and d6, and the third valve core (54) is used to control the on-off of the oil ports d7 and d8; the third valve core (54) has a hydraulic control end e6, and the pilot control valve group is used to control the on-off between the pump unit (2) and the hydraulic control end e6.

3. The hydraulic control system of claim 1, wherein, The rotating rod holding valve (6) comprises a second valve shell (61) and fourth, fifth and sixth valve cores (62, 63 and 64) arranged in the second valve shell (61), the second valve shell (61) has oil ports f1, f2, f3, f4, f5, f6, f7 and f8, the oil port f1 is communicated with the working oil port b3, the oil port f2 is communicated with the rodless cavity of the rotating rod cylinder (72), the oil port f3 is communicated with the oil port f4, the oil port f5 is communicated with the working oil port b3, the oil port f6 is communicated with the oil port f7, and the oil port f8 is communicated with the pump unit (2); the fourth valve core (62) is provided with a second throttle hole (621), one end of the second throttle hole (621) is communicated with the oil ports f1 and f2, and the other end is communicated with the oil port f3, the fourth valve core (62) is used for conducting or cutting off the oil ports f1 and f2, the fifth valve core (63) is used for conducting or cutting off the side where the oil port f4 is located and the side where the oil ports f5 and f6 are located, and the sixth valve core (64) is used for controlling the on-off of the oil ports f7 and f8; the sixth valve core (64) has a pilot control end e7, and the pilot control valve group is used for controlling the on-off between the pump unit (2) and the pilot control end e7.

4. The hydraulic control system of claim 1, wherein, The oil supplementing oil path comprises an oil supplementing pipe (8), a first oil supplementing overflow valve (81) and a second oil supplementing overflow valve (82); wherein, the first end of the oil supplementing pipe (8) is communicated with the pump unit (2), the second end of the oil supplementing pipe (8) is communicated with the oil tank (1), the oil supplementing pipe (8) is communicated with the oil inlet of the first oil supplementing overflow valve (81) and the oil inlet of the second oil supplementing overflow valve (82), the oil outlet of the first oil supplementing overflow valve (81) is communicated with the rodless cavity of the boom cylinder (71), and the oil outlet of the second oil supplementing overflow valve (82) is communicated with the rodless cavity of the rotating rod cylinder (72).

5. The hydraulic control system of claim 4, wherein, The oil supplementing oil path further comprises an oil supplementing floating valve (83), the oil supplementing floating valve (83) comprising a third valve shell (831), a seventh valve core (832) and an eighth valve core (833), the third valve shell (831) having an oil port g1, an oil port g2, an oil port g3, an oil port g4 and an oil port g5, the oil port g1 being communicated with a pipeline between the rod cavity of the boom cylinder (71) and the oil port a4, the oil port g2 being communicated with the oil supplementing pipe (8), the oil port g3 being communicated with the oil port g4, the oil port g5 being communicated with the oil tank (1); the seventh valve core (832) being provided with a third throttling hole (8321), one end of the third throttling hole (8321) being communicated with the oil port g1 and the oil port g2, the other end being communicated with the oil port g3, the seventh valve core (832) being used for conducting or cutting off the oil port g1 and the oil port g2, the eighth valve core (833) being used for controlling the on-off of the oil port g4 and the oil port g5, the pilot control valve group being used for controlling the on-off between the pump unit (2) and the pilot control end e8 of the eighth valve core (833).

6. The hydraulic control system of claim 1, wherein, The first boom reversing valve (31) is a three-position four-way reversing valve; wherein, When being located at the intermediate position, the oil inlet a1, the oil outlet a2, the working oil port a3 and the working oil port a4 are not communicated with each other; When being located at the first working position, the oil inlet a1 is communicated with the working oil port a3, and the oil outlet a2 is communicated with the working oil port a4; When being located at the second working position, the oil inlet a1 is communicated with the working oil port a4, the oil outlet a2 is communicated with the working oil port a3, and the working oil port a4 is configured to unilaterally conduct the oil inlet a1.

7. The hydraulic control system of claim 1, wherein, The working valve group further comprises a second boom reversing valve (33), the second boom reversing valve (33) having an oil inlet c1, an oil outlet c2 and a working oil port c3, the oil outlet end of the pump unit (2) being communicated with the oil inlet c1, the oil outlet c2 being communicated with the oil tank (1), and the working oil port c3 being communicated with the rodless cavity of the boom cylinder (71); the second boom reversing valve (33) being reversed by the pilot control valve group.

8. The hydraulic control system of claim 7, wherein, A first check valve (34) is arranged between the working oil port c3 and the rodless cavity of the boom cylinder (71), and the first check valve (34) is configured to unilaterally conduct the direction from the working oil port c3 to the rodless cavity of the boom cylinder (71).

9. The hydraulic control system of claim 8, wherein, The first boom reversing valve (31) has a pilot control end e1 and a pilot control end e2, the rotating rod reversing valve (32) has a pilot control end e3 and a pilot control end e4, the second boom reversing valve (33) has a pilot control end e5, and the pilot control valve group comprises a first pilot reversing valve (41), a second pilot reversing valve (42), a third pilot reversing valve (43), a fourth pilot reversing valve (44), a fifth pilot reversing valve (45) and a controller (46); wherein, The oil inlet of the first pilot directional valve (41), the oil inlet of the second pilot directional valve (42), the oil inlet of the third pilot directional valve (43), the oil inlet of the fourth pilot directional valve (44) and the oil inlet of the fifth pilot directional valve (45) are communicated with the oil outlet end of the pump unit (2), the oil outlet of the first pilot directional valve (41) is communicated with the hydraulic control end e1, the oil outlet of the second pilot directional valve (42) is communicated with the hydraulic control end e2, the oil outlet of the third pilot directional valve (43) is communicated with the hydraulic control end e3, the oil outlet of the fourth pilot directional valve (44) is communicated with the hydraulic control end e4, and the oil outlet of the fifth pilot directional valve (45) is communicated with the hydraulic control end e5. The controller (46) is used for controlling the first pilot directional valve (41), the second pilot directional valve (42), the third pilot directional valve (43), the fourth pilot directional valve (44) and the fifth pilot directional valve (45) to change direction.

10. A loader characterized by The hydraulic control system comprises a machine body, a movable arm and a rotating rod, the hydraulic control system is arranged on the machine body, the movable arm is connected to the piston rod of the movable arm cylinder (71), and the rotating rod is connected to the piston rod of the rotating rod cylinder (72).

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