Bucket and bucket rod composite hydraulic system and excavator

Abstract

The utility model relates to the technical field of excavators, in particular to a bucket and bucket rod composite hydraulic system and an excavator, the bucket and bucket rod composite hydraulic system comprises a bucket oil cylinder, a bucket rod oil cylinder, a first oil pump and a second oil pump, the bucket oil cylinder comprises a bucket rod cavity and a bucket rodless cavity, the bucket rod oil cylinder comprises a bucket rod rod cavity and a bucket rod rodless cavity which are variable in volume, the first oil pump can supply oil to one of the bucket rodless cavity and the bucket rod cavity, and the first oil pump and the second oil pump can jointly supply oil to one of the bucket rod rodless cavity and the bucket rod cavity. Oil is supplied to the bucket oil cylinder and the bucket rod oil cylinder through the first oil pump, oil is only supplied to the bucket rod oil cylinder through the second oil pump, a hydraulic system can be effectively simplified, and operability is improved.

Description

TECHNICAL FIELD

[0001] The utility model relates to excavator technical field especially relates to a bucket and bucket rod composite hydraulic system and excavator. BACKGROUND

[0002] The main actions on the hydraulic excavator have the whole machine walking (left walking, right walking), platform rotation and the boom, bucket rod and bucket action of the working device, and the main action performance of the hydraulic excavator includes the digging performance, loading performance, land leveling performance etc.

[0003] At present, the excavator usually adopts two variable plunger pumps + integral multi-way valve + centralized hydraulic system of multiple actuators, and the control mode mainly adopts hydraulic multi-way valve to distribute the flow to each actuator according to the demand, and the actuator at least includes the boom cylinder, bucket rod cylinder and bucket cylinder. SUMMARY

[0004] The utility model discloses a bucket and bucket rod composite hydraulic system and excavator to simplify the hydraulic system and improve the operability.

[0005] On the one hand, the utility model provides a bucket and bucket rod composite hydraulic system, the bucket and bucket rod composite hydraulic system includes bucket cylinder and bucket rod cylinder, the bucket cylinder includes the bucket rod cavity and the bucket cavity of variable volume, the bucket rod cylinder includes the bucket rod cavity and the bucket rod cavity of variable volume, the bucket and bucket rod composite hydraulic system still includes:

[0006] The first oil pump can supply oil to the bucket rod cavity or the bucket rod cavity,

[0007] The first oil pump and second oil pump are used for supplying oil to the bucket rod cavity or the bucket rod cavity.

[0008] As the preferred technical scheme of the bucket and bucket rod composite hydraulic system, the bucket and bucket rod composite hydraulic system still includes the oil supplement pump, one end of the oil supplement pump is connected with the oil tank, the other end is connected with the oil supplement oil path, and the input end of the first oil pump and the second oil pump is communicated with the oil supplement oil path.

[0009] As the preferred technical scheme of the bucket and bucket rod composite hydraulic system, the bucket and bucket rod composite hydraulic system still includes the first valve, the first valve can make the output end of the first oil pump and one of the bucket rod cavity and the bucket rod cavity be communicated, and make the oil tank and the other of the bucket rod cavity and the bucket rod cavity be communicated.

[0010] As the preferred technical scheme of the bucket and stick combined hydraulic system, the bucket and stick combined hydraulic system further comprises a second valve, the second valve can make the output end of the first oil pump communicate with one of the bucket rod cavity and the bucket rod cavity, and make the oil tank communicate with the other one of the bucket rod cavity and the bucket rod cavity.

[0011] As the preferred technical scheme of the bucket and stick combined hydraulic system, the bucket and stick combined hydraulic system further comprises a third valve, the third valve can make the output end of the second oil pump communicate with one of the bucket rod cavity and the bucket rod cavity, and make the oil tank communicate with the other one of the bucket rod cavity and the bucket rod cavity.

[0012] As the preferred technical scheme of the bucket and stick combined hydraulic system, the bucket and stick combined hydraulic system further comprises a bucket stick small cavity oil way communicating with the bucket stick rod cavity, and a fourth valve arranged in the bucket stick small cavity oil way.

[0013] The first valve and the third valve are connected with the bucket stick small cavity oil way through pipelines, and the fourth valve is used for opening or closing the bucket stick small cavity oil way.

[0014] As the preferred technical scheme of the bucket and stick combined hydraulic system, the bucket and stick combined hydraulic system further comprises a supply oil overflow valve, the supply oil overflow valve is used for overflowing the part of the oil output by the first oil pump and the second oil pump exceeding the set pressure to the oil tank.

[0015] As the preferred technical scheme of the bucket and stick combined hydraulic system, the bucket and stick combined hydraulic system further comprises an internal combustion engine, the internal combustion engine is simultaneously connected with the first oil pump and the second oil pump in transmission, and the internal combustion engine can drive the first oil pump and the second oil pump to rotate simultaneously.

[0016] As the preferred technical scheme of the bucket and stick combined hydraulic system, the bucket and stick combined hydraulic system further comprises a first motor and a second motor, the first motor is connected with the first oil pump in transmission, and the first motor can drive the first oil pump to rotate, the second motor is connected with the second oil pump in transmission, and the second motor can drive the second oil pump to rotate.

[0017] The bucket and stick combined hydraulic system provided by the utility model has at least the following beneficial effects:

[0018] The bucket and arm composite hydraulic system comprises a bucket oil cylinder, an arm oil cylinder, a first oil pump and a second oil pump, the bucket oil cylinder comprises a bucket rod cavity and a bucket rodless cavity, the arm oil cylinder comprises an arm rod cavity and an arm rodless cavity, the first oil pump can supply oil to one of the bucket rodless cavity and the bucket rod cavity, and the first oil pump and the second oil pump can jointly supply oil to one of the arm rodless cavity and the arm rod cavity, thereby effectively simplifying the hydraulic system and improving operability.

[0019] In another aspect, the utility model provides a kind of excavator, including the bucket and arm composite hydraulic system in any scheme above, and the excavator further includes boom oil cylinder, third oil pump and fourth oil pump, and the third oil pump and fourth oil pump are used to supply oil to the boom oil cylinder.

[0020] The excavator provided by the utility model has at least the following beneficial effects:

[0021] The excavator comprises the bucket and arm composite hydraulic system, and the composite hydraulic system of the bucket and arm has simple structure and high operability. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 It is the first structure schematic view of the bucket and arm composite hydraulic system in the utility model embodiment;

[0023] Figure 2 It is the second structure schematic view of the bucket and arm composite hydraulic system in the utility model embodiment;

[0024] Figure 3 It is the first local structure schematic view of the excavator in the utility model embodiment;

[0025] Figure 4 It is the first local structure schematic view of the excavator in the utility model embodiment.

[0026] In the drawing:

[0027] 1, bucket oil cylinder; 101, bucket rod cavity; 102, bucket rodless cavity;

[0028] 2, arm oil cylinder; 201, arm rod cavity; 202, arm rodless cavity;

[0029] 3, boom oil cylinder; 301, boom rod cavity; 302, boom rodless cavity;

[0030] 4, first oil pump; 5, second oil pump; 6, oil supplement pump; 7, oil supplement oil path; 8, oil tank; 9, oil supplement overflow valve; 10, first oil path; 11, second oil path; 12, arm big cavity oil path; 13, arm small cavity oil path; 14, bucket big cavity oil path; 15, bucket small cavity oil path; 16, return oil path; 17, first valve; 18, second valve; 19, third valve; 20, hydraulic control check valve; 21, electromagnetic reversing valve; 22, oil supply overflow valve; 23, first check valve; 24, second check valve; 25, throttle valve; 26, regeneration check valve; 27, internal combustion engine; 28, first motor; 29, second motor; 30, third oil pump; 31, fourth oil pump; 32, balance valve; 33, third motor; 34, battery; 35, third oil path; 36, fourth oil path; 37, fifth oil path; 38, oil supplement motor; 39, first control valve; 40, second control valve. DETAILED DESCRIPTION

[0031] The technical solutions of the present application will be described clearly and completely below in combination with the drawings. Obviously, the described embodiments are only some of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0032] In the description of the present application, it should be noted that the orientations or positional relationships indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. are based on the orientations or positional relationships shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application. In addition, the terms "first", "second", etc. are only for the purpose of description, and cannot be understood as indicating or implying relative importance. Among them, the terms "first position" and "second position" are two different positions, and moreover, the "above", "above" and "above" of the first feature on the second feature include the first feature above and obliquely above the second feature, or only indicate that the horizontal height of the first feature is higher than that of the second feature. The "below", "below" and "below" of the first feature on the second feature include the first feature below and obliquely below the second feature, or only indicate that the horizontal height of the first feature is less than that of the second feature.

[0033] In the description of the utility model, it is necessary to explain that, unless there is definite stipulation and limitation, the terms "mount", "link", "connect" should be understood in broad sense, for example, it can be fixed connection, also can be detachable connection, or integrally connected, can be mechanical connection, also can be electrical connection, can be direct connection, also can be indirectly connected through intermediate medium, can be the intercommunication of two elements. For ordinary skilled in the art, the specific meaning of the above terms in the utility model can be understood according to specific circumstances.

[0034] The embodiments of the utility model are described in detail below, and the examples of the embodiments are shown in the drawings, wherein the same or similar reference signs represent the same or similar elements or elements with the same or similar functions throughout. The embodiments described below by referring to the drawings are exemplary, only for explaining the utility model, and cannot be understood as the limitation of the utility model.

[0035] At present, excavator usually adopts two variable plunger pumps + integral multi-way valve + multi-actuator centralized hydraulic system, and the control mode mainly adopts hydraulic multi-way valve to distribute flow to each actuator according to demand, and the actuator at least includes boom cylinder, stick cylinder and bucket cylinder, due to the difference of load of each actuator, it will cause serious energy waste, and the flow distribution of multi-actuator is complex, and the operability is poor.

[0036] To this end, the embodiment provides a bucket and stick composite hydraulic system to solve the above problems.

[0037] As shown in Figure 1 and Figure 2 , the bucket and stick composite hydraulic system includes bucket cylinder 1 and stick cylinder 2.

[0038] The bucket cylinder 1 includes a variable-volume bucket rod cavity 101 and a bucket rodless cavity 102, and the bucket cylinder 1 further includes a bucket piston rod and a bucket cylinder body, the bucket piston rod separates the inner cavity of the bucket cylinder body into the bucket rod cavity 101 and the bucket rodless cavity 102, the bucket piston rod passes through the bucket rod cavity 101 so that the cross-sectional area of the bucket rod cavity 101 is smaller than that of the bucket rodless cavity 102, the bucket piston rod can move in the bucket cylinder body, and when the bucket piston rod moves, the volumes of the bucket rod cavity 101 and the bucket rodless cavity 102 increase and decrease respectively. In the embodiment, the bucket cylinder body is hinged with the stick, the bucket piston rod is hinged with the bucket, and the number of the bucket cylinder 1 is specifically one.

[0039] The arm cylinder 2 comprises a variable-volume arm rod cavity 201 and an arm rod cavity 202, and further comprises an arm rod piston rod and an arm cylinder body. The arm rod piston rod separates the inner cavity of the arm cylinder body into the arm rod cavity 201 and the arm rod cavity 202. The arm rod piston rod passes through the arm rod cavity 201, so that the sectional area of the arm rod cavity 201 is smaller than that of the arm rod cavity 202. The arm rod piston rod is movable in the arm cylinder body, and the movement of the arm rod piston rod causes the volumes of the arm rod cavity 201 and the arm rod cavity 202 to increase and decrease, respectively. In this embodiment, the arm cylinder body is hingedly connected to the boom, the arm rod piston rod is hingedly connected to the arm, and the number of arm cylinders 2 is one.

[0040] Optionally, the bucket-arm combined hydraulic system further comprises a first oil pump 4 and a second oil pump 5. The first oil pump 4 is capable of supplying oil to one of the bucket rod cavity 102 and the bucket rod cavity 101, and the first oil pump 4 is also capable of supplying oil to one of the arm rod cavity 202 and the arm rod cavity 201 together with the second oil pump 5. In this way, the first oil pump 4 is used to supply oil to the bucket cylinder 1 and the arm cylinder 2, respectively, and the second oil pump 5 is used to supply oil to only the arm cylinder 2, which can effectively simplify the hydraulic system and improve operability. Preferably, the first oil pump 4 and the second oil pump 5 are both open pumps.

[0041] Specifically, when the bucket cylinder 1 acts alone, the working power of the first oil pump 4 is determined according to the oil demand of the bucket cylinder 1, and the first oil pump 4 is used to supply oil to the bucket cylinder 1; when the arm cylinder 2 acts alone, the working power of the second oil pump 5 is determined according to the oil demand of the arm cylinder 2, and the second oil pump 5 is used to supply oil to the arm cylinder 2; when the bucket cylinder 1 and the arm cylinder 2 act in combination, the total oil supply power of the first oil pump 4 and the second oil pump 5 is determined according to the oil demand of the bucket cylinder 1 and the arm cylinder 2. If the maximum power of the first oil pump 4 is greater than the oil supply power, the oil supply power can be provided by the first oil pump 4 alone; if the maximum power of the first oil pump 4 is less than the oil supply power, the oil supply power is shared by the first oil pump 4 and the second oil pump 5, which can effectively improve the operability.

[0042] The determination of the working power of the first oil pump 4 according to the oil demand of the bucket cylinder 1, the determination of the working power of the second oil pump 5 according to the oil demand of the arm cylinder 2, and the determination of the total oil supply power of the first oil pump 4 and the second oil pump 5 according to the oil demand of the bucket cylinder 1 and the arm cylinder 2 are all prior art. Taking the determination of the working power of the first oil pump 4 according to the oil demand of the bucket cylinder 1 as an example, a mapping relationship between the oil demand of the bucket cylinder 1 and the working power of the first oil pump 4 can be pre-stored in the control terminal. The oil demand of the bucket cylinder 1 is obtained through interaction with the vehicle controller, and the working power of the first oil pump 4 is determined according to the mapping relationship.

[0043] Optionally, the bucket and arm combined hydraulic system further comprises a make-up pump 6, one end of the make-up pump 6 is connected to the oil tank 8, and the other end is connected to a make-up oil path 7, the input ends of the first oil pump 4 and the second oil pump 5 are in communication with the make-up oil path 7. By setting the make-up pump 6 to supply oil to the first oil pump 4 and the second oil pump 5, the load requirement of the first oil pump 4 and the second oil pump 5 can be reduced. In the embodiment, the make-up pump 6 is driven by a make-up motor 38.

[0044] Optionally, the bucket and arm combined hydraulic system further comprises a make-up overflow valve 9 arranged in the make-up oil path 7, the make-up overflow valve 9 is used to overflow the oil in the make-up oil path 7 exceeding the set pressure to the oil tank 8.

[0045] Optionally, the bucket and arm combined hydraulic system further comprises a first oil path 10, a second oil path 11, an arm large cavity oil path 12 in communication with the arm rodless cavity 202, an arm small cavity oil path 13 in communication with the arm rod cavity 201, a bucket large cavity oil path 14 in communication with the bucket rodless cavity 102, a bucket small cavity oil path 15 in communication with the bucket rod cavity 101, and a return oil path 16 in communication with the oil tank 8. Among them, the first oil path 10 is connected with the output end of the first oil pump 4; the second oil path 11 is connected with the output end of the second oil pump 5.

[0046] Optionally, in the embodiment, the bucket and arm combined hydraulic system further comprises a first valve 17. The first valve 17 can make the output end of the first oil pump 4 communicate with one of the arm rod cavity 201 and the arm rodless cavity 202, and make the oil tank 8 communicate with the other one of the arm rod cavity 201 and the arm rodless cavity 202.

[0047] Specifically, the first valve 17 at least comprises a P1 interface, an A1 interface, a B1 interface and a T1 interface, the P1 interface is connected with the first oil path 10, the A1 interface is connected with the arm large cavity oil path 12, the B1 interface is connected with the arm small cavity oil path 13, and the T1 interface is connected with the return oil path 16, the first valve 17 has a first left position and a first right position, as shown in Figure 1 When the first valve 17 is in the first right position, the P1 interface communicates with the A1 interface, and the B1 interface communicates with the T1 interface, thereby making the first oil path 10 communicate with the arm large cavity oil path 12, and the return oil path 16 communicate with the arm small cavity oil path 13, a part of the oil pumped by the first oil pump 4 can be pumped to the arm rodless cavity 202 through the first valve 17, and the oil in the arm rod cavity 201 is transported to the return oil path 16 through the first valve 17, and then enters the oil tank 8. As shown in Figure 2As shown, when the first valve 17 is located at the first left position, the P1 interface is in communication with the B1 interface, and the A1 interface is in communication with the T1 interface, so that the first oil path 10 is in communication with the arm small cavity oil path 13, the oil return oil path 16 is in communication with the arm large cavity oil path 12, and a part of the oil pumped by the first oil pump 4 can be pumped to the arm rod cavity 201 through the first valve 17, and the oil in the arm rodless cavity 202 is transported to the oil return oil path 16 through the first valve 17, and then enters the oil tank 8.

[0048] Optionally, in the embodiment, the bucket and arm combined hydraulic system further comprises a second valve 18, which can make the output end of the first oil pump 4 in communication with one of the bucket rod cavity 101 and the bucket rodless cavity 102, and make the oil tank 8 in communication with the other one of the bucket rod cavity 101 and the bucket rodless cavity 102.

[0049] Specifically, the second valve 18 at least comprises a P2 interface, an A2 interface, a B2 interface and a T2 interface, the P2 interface is connected with the first oil path 10, the A2 interface is connected with the bucket large cavity oil path 14, the B2 interface is connected with the bucket small cavity oil path 15, and the T2 interface is connected with the oil return oil path 16, and the second valve 18 has a second left position and a second right position, as shown in the following figure. Figure 1 As shown, when the second valve 18 is located at the second right position, the P2 interface is in communication with the A2 interface, and the B2 interface is in communication with the T2 interface, so that the first oil path 10 is in communication with the bucket large cavity oil path 14, the oil return oil path 16 is in communication with the bucket small cavity oil path 15, and another part of the oil pumped by the first oil pump 4 can be pumped to the bucket rodless cavity 102 through the second valve 18, and the oil in the bucket rod cavity 101 is transported to the oil return oil path 16 through the second valve 18, and then enters the oil tank 8. As shown in the following figure. Figure 2 As shown, when the second valve 18 is located at the second left position, the P2 interface is in communication with the B2 interface, and the A2 interface is in communication with the T2 interface, so that the first oil path 10 is in communication with the bucket small cavity oil path 15, the oil return oil path 16 is in communication with the bucket large cavity oil path 14, and another part of the oil pumped by the first oil pump 4 can be pumped to the bucket rod cavity 101 through the second valve 18, and the oil in the bucket rodless cavity 102 is transported to the oil return oil path 16 through the second valve 18, and then enters the oil tank 8.

[0050] Optionally, in the embodiment, the bucket and arm combined hydraulic system further comprises a third valve 19, which can make the output end of the second oil pump 5 in communication with one of the arm rod cavity 201 and the arm rodless cavity 202, and make the oil tank 8 in communication with the other one of the arm rod cavity 201 and the arm rodless cavity 202.

[0051] Specifically, the third valve 19 at least comprises a P3 interface, an A3 interface, a B3 interface, a T 31 interface and a T 32The interface P3 is connected with the second oil path 11, the interface A3 is connected with the bucket rod large cavity oil path 12, the interface B3 is connected with the bucket rod small cavity oil path 13, and the interface T 31 The interface P3 is connected with the second oil path 11, the interface A3 is connected with the bucket rod large cavity oil path 12, the interface B3 is connected with the bucket rod small cavity oil path 13, and the interface T 32 The interface P3 is connected with the second oil path 11, the interface A3 is connected with the bucket rod large cavity oil path 12, the interface B3 is connected with the bucket rod small cavity oil path 13, and the interface T Figure 1 The interface P3 is connected with the second oil path 11, the interface A3 is connected with the bucket rod large cavity oil path 12, the interface B3 is connected with the bucket rod small cavity oil path 13, and the interface T 31 The interface P3 is connected with the second oil path 11, the interface A3 is connected with the bucket rod large cavity oil path 12, the interface B3 is connected with the bucket rod small cavity oil path 13, and the interface T 32 The interface P3 is connected with the second oil path 11, the interface A3 is connected with the bucket rod large cavity oil path 12, the interface B3 is connected with the bucket rod small cavity oil path 13, and the interface T Figure 2 The interface P3 is connected with the second oil path 11, the interface A3 is connected with the bucket rod large cavity oil path 12, the interface B3 is connected with the bucket rod small cavity oil path 13, and the interface T 32 The interface P3 is connected with the second oil path 11, the interface A3 is connected with the bucket rod large cavity oil path 12, the interface B3 is connected with the bucket rod small cavity oil path 13, and the interface T 31 The interface P3 is connected with the second oil path 11, the interface A3 is connected with the bucket rod large cavity oil path 12, the interface B3 is connected with the bucket rod small cavity oil path 13, and the interface T

[0052] In the embodiment, the first valve 17, the second valve 18 and the third valve 19 are all solenoid valves, and in other embodiments, the first valve 17, the second valve 18 and the third valve 19 can also be liquid control valves according to needs.

[0053] Optionally, the bucket and bucket rod combined hydraulic system further comprises a throttle valve 25 arranged between the interface T 31 The interface P3 is connected with the second oil path 11, the interface A3 is connected with the bucket rod large cavity oil path 12, the interface B3 is connected with the bucket rod small cavity oil path 13, and the interface T

[0054] Optionally, the bucket and bucket rod combined hydraulic system further comprises a regenerative check valve 26 integrated in the third valve 19, the regenerative check valve 26 is connected between the interface A3 and the interface B3 only when the third valve 19 is in the third left position, and the regenerative check valve 26 is configured to allow oil to flow from the interface B3 to the interface A3 only. At this time, if the oil pressure in the bucket rod large cavity 201 is greater than the oil pressure in the bucket rod small cavity 202, the oil in the bucket rod small cavity oil path 13 can flow directly into the bucket rod large cavity oil path 12 through the regenerative check valve 26, so as to reduce the oil pumping load of the first oil pump 4 and the second oil pump 5, and to realize the rapid movement of the bucket rod piston rod.

[0055] Optionally, the bucket and arm composite hydraulic system further comprises a fourth valve arranged in the arm small cavity oil path 13; the first valve 17 and the third valve 19 are connected with the arm small cavity oil path 13 through pipelines, and the fourth valve is used for connecting or disconnecting the arm small cavity oil path 13. When the fourth valve disconnects the arm small cavity oil path 13, the oil pressure in the arm cavity 201 of the arm is stable, and the position of the arm cylinder 2 is kept stable.

[0056] The fourth valve comprises a hydraulic control check valve 20 and an electromagnetic reversing valve 21. The hydraulic control check valve 20 comprises a check valve valve housing and a check valve spool. The check valve valve housing has a first working interface and a second working interface, which are connected in series to the arm small cavity oil path 13, and the first working interface is closer to the arm cavity 201 than the second working interface. The check valve spool is slidably arranged in the check valve valve housing, and the check valve spool divides the inner cavity of the check valve valve housing into a spring cavity and a working cavity. The check valve spool can slide relative to the check valve valve housing to have an open position and a closed position. When the check valve spool is in the closed position, the check valve spool can further divide the working cavity into a first cavity and a second cavity, which are not connected to each other. The first working interface is always connected to the first cavity, and the second working interface is always connected to the second cavity. Because the first cavity and the second cavity are separated, the arm small cavity oil path 13 is disconnected. When the check valve spool is in the open position, the first cavity and the second cavity are connected, so that the arm small cavity oil path 13 is connected.

[0057] The hydraulic control check valve 20 further comprises a check valve spring. The check valve valve housing has a first control interface and a second control interface. The check valve spring is arranged in the spring cavity, and the two ends of the check valve spring are in abutment with the check valve spool and the check valve valve housing, respectively. The first control interface is always connected to the first cavity, and the second control interface is always connected to the spring cavity. The check valve spring and the hydraulic oil in the spring cavity give the check valve spool a force F1 to move to the closed position. The hydraulic oil in the working cavity gives the check valve spool a force F2 to move to the open position. The forces F1 and F2 are compared to determine the position of the check valve spool.

[0058] Further, the electromagnetic reversing valve 21 is a two-position three-way valve, which is used to connect the first control interface and the second control interface of the hydraulic control check valve 20. At this time, the oil pressure in the working cavity and the spring cavity of the hydraulic control check valve 20 is equal, and the check valve spring in the spring cavity also gives the check valve spool a force to move to the closed position, so as to ensure that the arm small cavity oil path 13 is stably closed. The electromagnetic reversing valve 21 can also connect the second control interface to the oil tank 8 and disconnect the first control interface. At this time, the forces F1 and F2 are compared to determine the position of the check valve spool. When F1 < F2, the check valve spring is compressed, so as to move the check valve spool to the open position, and then open the arm small cavity oil path 13.

[0059] Optionally, the bucket and arm combined hydraulic system further comprises a supply relief valve 22, the supply relief valve 22 is used for overflowing the oil exceeding the set oil pressure output by the first oil pump 4 and the second oil pump 5 to the oil tank 8. Specifically, the input end of the supply relief valve 22 is connected to the first oil path 10 and the second oil path 11 at the same time, and the overflow end of the supply relief valve 22 is connected to the return oil path 16. By arranging the supply relief valve 22, the oil pressure output by the first oil pump 4 and the second oil pump 5 is stabilized.

[0060] Optionally, the bucket and arm combined hydraulic system further comprises a first one-way valve 23 arranged between the first oil path 10 and the supply relief valve 22, and a second one-way valve 24 arranged between the second oil path 11 and the supply relief valve 22. The first one-way valve 23 only allows the oil to flow from the first oil path 10 to the supply relief valve 22, and the second one-way valve 24 only allows the oil to flow from the second oil path 11 to the supply relief valve 22.

[0061] Optionally, please refer to Figure 1 , the bucket and arm combined hydraulic system further comprises an internal combustion engine 27, the internal combustion engine 27 is drivingly connected with the first oil pump 4 and the second oil pump 5 at the same time, and the internal combustion engine 27 can drive the first oil pump 4 and the second oil pump 5 to rotate at the same time. By arranging the internal combustion engine 27, power can be provided to drive the first oil pump 4 and the second oil pump 5 to operate.

[0062] As one of the alternative solutions, please refer to Figure 2 , the bucket and arm combined hydraulic system further comprises a first motor 28 and a second motor 29, the first motor 28 is drivingly connected with the first oil pump 4, and the first motor 28 can drive the first oil pump 4 to rotate; the second motor 29 is drivingly connected with the second oil pump 5, and the second motor 29 can drive the second oil pump 5 to rotate. By arranging the first motor 28 and the second motor 29, power can also be provided to drive the first oil pump 4 and the second oil pump 5 to operate.

[0063] The embodiment also provides an excavator, which comprises the bucket and arm combined hydraulic system in the above-mentioned solution. The excavator further comprises an arm cylinder 3, a third oil pump 30 and a fourth oil pump 31, the third oil pump 30 and the fourth oil pump 31 are used for supplying oil to the arm cylinder 3.

[0064] Please refer to Figure 3 and Figure 4The boom cylinder 3 comprises a variable-volume boom rod cavity 301 and a boom rodless cavity 302. The boom cylinder 3 further comprises a boom piston rod and a boom cylinder body, the boom piston rod separates the inner cavity of the boom cylinder body into the boom rod cavity 301 and the boom rodless cavity 302, the boom piston rod passes through the boom rod cavity 301 so that the cross-sectional area of the boom rod cavity 301 is smaller than that of the boom rodless cavity 302, the boom piston rod is movable in the boom cylinder body, and the movement of the boom piston rod causes the volumes of the boom rod cavity 301 and the boom rodless cavity 302 to increase and decrease respectively. In this embodiment, the boom cylinder body is hinged to the body of the excavator, the boom piston rod is hinged to the boom, and the number of boom cylinders 3 is two.

[0065] One end of the third oil pump 30 is connected to the boom rodless cavity 302, the other end of the third oil pump 30 is connected to the boom rod cavity 301, the third oil pump 30 can rotate forward and reverse; one end of the fourth oil pump 31 is connected to the oil supplementing oil path 7, the other end of the fourth oil pump 31 is connected to the boom rodless cavity 302, the fourth oil pump 31 can rotate forward and reverse. In this embodiment, the third oil pump 30 and the fourth oil pump 31 are both closed oil pumps, specifically, they can be closed constant displacement pumps, the third oil pump 30 and the two oil cavities of the boom cylinder 3 form a hydraulic circuit, the fourth oil pump 31 and the boom rodless cavity 302 and the oil supplementing oil path 7 form a hydraulic circuit, compared with open pumps, energy loss can be effectively reduced; and the boom cylinder 3 is supplied with oil by the third oil pump 30 and the fourth oil pump 31, which realizes the decoupling of the boom cylinder 3 and facilitates the improvement of the control performance of the boom cylinder 3.

[0066] In this embodiment, the boom piston rod can move relative to the boom cylinder body to have an extended position and a retracted position, when the boom piston rod moves to the extended position, the boom piston rod gradually extends outward, the third oil pump 30 rotates forward, and pumps the oil in the boom rod cavity 301 to the boom rodless cavity 302, but because the cross-sectional area of the boom rod cavity 301 is smaller than that of the boom rodless cavity 302, there is a flow difference between the two, so the fourth oil pump 31 also needs to pump the oil in the oil supplementing oil path 7 to the boom rodless cavity 302 at the same time to make up for the flow difference, at this time, the fourth oil pump 31 also rotates forward. When the boom piston rod moves to the retracted position, the boom piston rod gradually retracts inward, the third oil pump 30 reverses, and pumps part of the oil in the boom rodless cavity 302 to the boom rod cavity 301, at the same time, the fourth oil pump 31 reverses, and pumps another part of the oil in the boom rodless cavity 302 to the oil supplementing oil path 7.

[0067] Optionally, the excavator further comprises a balance valve 32. The balance valve 32 communicates the one of the boom rodless chamber 302 and the boom rod chamber 301 with lower oil pressure with the oil supplement oil line 7. By arranging the balance valve 32, the oil in the one of the boom rodless chamber 302 and the boom rod chamber 301 with lower oil pressure can directly enter the oil supplement oil line 7, or the oil in the oil supplement oil line 7 directly enters the one of the boom rodless chamber 302 and the boom rod chamber 301 with lower oil pressure. When the temperature of the oil in the hydraulic circuit is too high, the oil with relatively low temperature in the oil supplement oil line 7 can replace the hot oil in the hydraulic circuit, so that the oil temperature in the hydraulic circuit is normal, thereby ensuring the normal operation of the boom cylinder 3, and the temperature monitoring is not required, and the cost can be effectively reduced.

[0068] In the embodiment, one end of the first oil pump 4 is communicated with the boom rodless chamber 302 through the third oil line 35, the other end of the first oil pump 4 is communicated with the boom rod chamber 301 through the fourth oil line 36, and the second oil pump 5 is communicated with the third oil line 35 through the fifth oil line 37. When the oil pressure in the boom rodless chamber 302 is greater than the oil pressure in the boom rod chamber 301, the balance valve 32 communicates the fourth oil line 36 and the oil supplement oil line 7. When the oil pressure in the boom rodless chamber 302 is less than the oil pressure in the boom rod chamber 301, the balance valve 32 communicates the third oil line 35 and the oil supplement oil line 7.

[0069] Specifically, the balance valve 32 comprises a P4 interface, an A4 interface and a B4 interface. The P4 interface communicates with the oil supplement oil line 7, the A4 interface is communicated with the third oil line 35, and the B4 interface is communicated with the fourth oil line 36. The balance valve 32 has a fourth left position and a fourth right position. When the balance valve 32 is in the fourth left position, the balance valve 32 communicates the P4 interface and the B4 interface, and disconnects the A4 interface, so that the oil supplement oil line 7 is communicated with the fourth oil line 36, and the oil supplement oil line 7 is disconnected with the third oil line 35. When the balance valve 32 is in the fourth right position, the balance valve 32 communicates the P4 interface and the A4 interface, and disconnects the B4 interface, so that the oil supplement oil line 7 is communicated with the third oil line 35, and the oil supplement oil line 7 is disconnected with the fourth oil line 36. Preferably, the balance valve 32 further has a first neutral position. When the balance valve 32 is in the first neutral position, the P4 interface is disconnected, the A4 interface is disconnected, and the B4 interface is disconnected, so that the oil supplement oil line 7 is disconnected with the third oil line 35 and the fourth oil line 36 at the same time.

[0070] The balance valve 32 is specifically a hydraulic control valve. The balance valve 32 has a first hydraulic control end and a second hydraulic control end. The first hydraulic control end is connected to the third oil circuit 35, and the second hydraulic control end is connected to the fourth oil circuit 36. The first hydraulic control end and the second hydraulic control end are located on both sides of the valve core of the balance valve 32, and the oil from the first hydraulic control end and the second hydraulic control end directly acts on the valve core of the balance valve 32. The stop position of the valve core of the balance valve 32 is determined by comparing the force exerted on the valve core by the oil from the first hydraulic control end and the force exerted on the valve core by the oil from the second hydraulic control end.

[0071] The excavator also includes a first control valve 39 disposed in the third oil circuit 35. The first control valve 39 is located between the connection point of the fifth oil circuit 37 and the third oil circuit 35 and the boom rodless chamber 302. The first control valve 39 is used to control the connection and disconnection of the third oil circuit 35. When the first control valve 39 controls the third oil circuit 35 to disconnect, it can keep the oil pressure in the boom rodless chamber 302 stable, thereby ensuring that the boom cylinder 3 can remain stable. In this embodiment, the first control valve 39 is specifically a hydraulically controlled check valve.

[0072] Optionally, the excavator also includes a second control valve 40, which is located in the fifth oil passage 37 and between the connection between the fifth oil passage 37 and the third oil passage 35 and the first oil pump 4. The second control valve 40 is used to control the connection or disconnection of the third oil passage 35. When the second control valve 40 disconnects the third oil passage 35, it can block the first oil pump 4 from supplying oil to the third oil passage 35 and prevent the oil in the third oil passage 35 from flowing to the first oil pump 4. At this time, only the second oil pump 5 drives the boom cylinder 3. Specifically, in this embodiment, the second control valve 40 is a hydraulic control valve, such as a three-position three-way hydraulic control valve.

[0073] Optionally, the excavator also includes a third motor 33 and a battery 34. The third motor 33 can rotate forward and reverse. It is connected to both the third oil pump 30 and the fourth oil pump 31, and can simultaneously drive both pumps. The battery 34 is electrically connected to the first motor 28, the second motor 29, the third motor 33, and the auxiliary oil motor 38. By controlling the speed of the third motor 33, the extension and retraction speeds of the boom piston rod of the boom cylinder 3 are controlled. Furthermore, when the boom piston rod retracts, the boom lowers under its own weight, and the fourth oil pump 31 drives the third motor 33 to rotate in reverse, generating electricity which is stored in the battery 34, thus achieving energy recovery and utilization of the system.

[0074] Obviously, the above embodiments of the present application are merely examples for clearly illustrating the present application, and are not intended to limit the implementation modes of the present application. For those skilled in the art, other different forms of changes or variations can be made on the basis of the above description. Here, it is not necessary and also impossible to exhaust all the implementation modes. Any modification, equivalent replacement and improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application claims.

Claims

1. A combined hydraulic system for a bucket and a stick, comprising a bucket cylinder (1) and a stick cylinder (2), wherein the bucket cylinder (1) includes a variable-volume bucket rod chamber (101) and a variable-volume bucket rodless chamber (102), and the stick cylinder (2) includes a variable-volume stick rod chamber (201) and a variable-volume stick rodless chamber (202), characterized in that, The combined hydraulic system of the bucket and stick also includes a first oil pump (4) and a second oil pump (5): The first oil pump (4) can supply oil to one of the bucket rodless chamber (102) and the bucket rod chamber (101). The first oil pump (4) can also supply oil to one of the stick rodless chamber (202) and the stick rod chamber (201) together with the second oil pump (5).

2. The bucket and boom combined hydraulic system according to claim 1, characterized in that, The combined hydraulic system of the bucket and stick also includes a replenishing pump (6), one end of which is connected to the oil tank (8) and the other end is connected to the replenishing oil circuit (7). The input ends of the first oil pump (4) and the second oil pump (5) are both connected to the replenishing oil circuit (7).

3. The bucket and boom combined hydraulic system according to claim 2, characterized in that, The bucket and stick combined hydraulic system also includes a first valve (17), which enables the output end of the first oil pump (4) to be connected to one of the stick rod chamber (201) and the stick rodless chamber (202), and enables the oil tank (8) to be connected to the other of the stick rod chamber (201) and the stick rodless chamber (202).

4. The bucket and stick combined hydraulic system according to claim 3, characterized in that, The combined hydraulic system of bucket and stick also includes a second valve (18), which enables the output end of the first oil pump (4) to be connected to one of the bucket rod chamber (101) and the bucket rodless chamber (102), and to the oil tank (8) to be connected to the other of the bucket rod chamber (101) and the bucket rodless chamber (102).

5. The bucket and boom combined hydraulic system according to claim 3, characterized in that, The combined hydraulic system of bucket and stick also includes a third valve (19), which enables the output end of the second oil pump (5) to be connected to one of the stick rod chamber (201) and the stick rodless chamber (202), and enables the oil tank (8) to be connected to the other of the stick rod chamber (201) and the stick rodless chamber (202).

6. The bucket and boom combined hydraulic system according to claim 5, characterized in that, The bucket and stick combined hydraulic system also includes a stick small chamber oil passage (13) connected to the stick rod chamber (201), and a fourth valve disposed in the stick small chamber oil passage (13); The first valve (17) and the third valve (19) are both connected to the boom small chamber oil passage (13) through pipelines, and the fourth valve is used to open or close the boom small chamber oil passage (13).

7. The bucket and stick combined hydraulic system according to claim 1, characterized in that, The combined hydraulic system of the bucket and stick also includes an oil supply overflow valve (22), which is used to overflow the portion of the oil output by the first oil pump (4) and the second oil pump (5) that exceeds the set pressure to the oil tank.

8. The bucket and stick combined hydraulic system according to any one of claims 1-7, characterized in that, The combined hydraulic system of bucket and boom also includes an internal combustion engine (27), which is simultaneously connected to the first oil pump (4) and the second oil pump (5), and the internal combustion engine (27) can drive the first oil pump (4) and the second oil pump (5) to rotate simultaneously.

9. The bucket and stick combined hydraulic system according to any one of claims 1-7, characterized in that, The bucket and boom combined hydraulic system also includes a first motor (28) and a second motor (29). The first motor (28) is connected to the first oil pump (4) and can drive the first oil pump (4) to rotate. The second motor (29) is connected to the second oil pump (5) and can drive the second oil pump (5) to rotate.

10. An excavator, characterized in that, The excavator includes the bucket and boom combined hydraulic system according to any one of claims 1-9, and further includes a boom cylinder (3), a third oil pump (30) and a fourth oil pump (31), wherein the third oil pump (30) and the fourth oil pump (31) are both used to supply oil to the boom cylinder (3).

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