Hybrid hydraulic system

Abstract

The application discloses a kind of hybrid hydraulic systems, comprising: engine, first hydraulic pump, clutch, generator and second hydraulic pump connected coaxially in sequence;Main multi-way valve, including a plurality of main working connection and for a plurality of main working connection oil supply total oil inlet;Wherein, the first pumping oil path of the first hydraulic pump and the second pumping oil path of the second hydraulic pump are parallelly connected and gathered in the total oil inlet of the main multi-way valve. Wherein, conventional load-sensitive pump, electromagnetic clutch, load-sensitive multi-way valve can be used as hybrid hydraulic system components, so that the power of engine and generator is mixed in the form of hydraulic transmission, mechanical coupling and impact-free power mixing can be easily realized, and the requirements for mechanical structure and electrical control are reduced.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of aerial work machines, and particularly relates to a hybrid power hydraulic system of an aerial work machine. BACKGROUND

[0002] The aerial work machines generally adopt a hydraulic transmission mode, and mechanical energy converted from chemical energy of a fuel engine or electric energy of an electric motor is transmitted to an actuator through a hydraulic system. In the industry, in order to make aerial work more energy-saving and environmentally friendly, electric drive and hybrid power forms are widely used in aerial work machines.

[0003] In indoor application scenarios where charging is convenient, tail gas pollution is prohibited, and noise is strictly controlled, electric drive aerial vehicles can basically meet the demand of most working conditions, but in outdoor scenarios where charging is inconvenient, fuel power is still a better choice. In order to balance environmental protection requirements and endurance, make the product have stronger scene adaptability and utilization, as a hybrid power product integrating the advantages of fuel power endurance and electric drive environmental protection, it becomes the optimal compromise scheme that can meet the different requirements.

[0004] In the existing hybrid technology, some technologies rely more on mechanical transmission devices for power transmission, and the structure is relatively complex. The hydraulic system is mainly used to drive the cylinder type actuator and recover potential energy to drive the generator to generate electricity. Some technologies use additional accumulators and optimized control methods to better improve the performance of the hydraulic transmission system. Some technologies use pneumatic and electric power supply methods to provide power for the hydraulic system, and the hydraulic system structure and control are relatively simple, suitable for specific conditions, and the use range is limited. Some technologies use the commonly used internal combustion engine and motor combination power supply scheme of aerial work machines. This hybrid power structure form that connects the internal combustion engine and the motor with a clutch to jointly provide power is relatively complex in control, and the speed and torque of the internal combustion engine and the motor need to be matched in real time. When the speed and torque matching error occurs, one of the power in the hybrid power system may appear over output or no output phenomenon, which will face the risk of excessive energy consumption and connection shaft overload. SUMMARY

[0005] To overcome at least one of the above technical defects, the application provides a hybrid power hydraulic system to realize power mixing without mechanical coupling and impact.

[0006] To achieve the above purpose, the application provides a hybrid power hydraulic system, comprising:

[0007] an engine, a first hydraulic pump, a clutch, a generator and a second hydraulic pump connected coaxially in sequence;

[0008] The main multi-way valve comprises a plurality of main working connections and a total oil inlet for supplying oil to the plurality of main working connections;

[0009] The first pumping oil path of the first hydraulic pump and the second pumping oil path of the second hydraulic pump are connected in parallel to the total oil inlet of the main multi-way valve.

[0010] In some embodiments, the hybrid hydraulic system comprises:

[0011] The front multi-way valve is arranged in the first pumping oil path and is used to control the output flow of the first hydraulic pump.

[0012] The front multi-way valve comprises a front working connection, and a working oil port of the front working connection is connected to the total oil inlet of the main multi-way valve.

[0013] In some embodiments, the first pumping oil path is provided with a first one-way valve for preventing pumping backflow, the second pumping oil path is provided with a second one-way valve for preventing pumping backflow, and the first one-way valve is arranged on a connecting oil path between the working oil port of the front working connection and the total oil inlet.

[0014] In some embodiments, the front multi-way valve comprises a front unloading valve, and the main multi-way valve comprises a main unloading valve.

[0015] In some embodiments, the first hydraulic pump and the second hydraulic pump are load-sensitive hydraulic pumps capable of automatic displacement adjustment according to feedback pressure, and the front multi-way valve and the main multi-way valve are load-sensitive hydraulic multi-way valves.

[0016] In some embodiments, the hybrid hydraulic system comprises a controller configured to:

[0017] Control the generator motor to drive the second hydraulic pump to work, and pump pressure oil to the total oil inlet through the second pumping oil path.

[0018] Control the main working connection to work, wherein the main working connection feeds back a throttle port pressure signal to the second hydraulic pump control valve.

[0019] Control the generator motor to operate at a constant economic speed.

[0020] The second hydraulic pump automatically adjusts the pump displacement according to the total flow demand corresponding to the flow control signal of each main working connection.

[0021] In some embodiments, the hybrid hydraulic system comprises a controller configured to:

[0022] controlling the engine to drive the first hydraulic pump to work, and pressure oil pumped by the first pumping oil passage to the total oil inlet through the front working connection of the front multi-way valve;

[0023] controlling the front working connection to work and feeding back a control valve throttle port pressure signal to the first hydraulic pump;

[0024] controlling the engine to operate at a constant economic speed;

[0025] wherein the controller is further configured to adjust the output flow of the front working connection according to the total flow demand corresponding to the control signal of each main working connection, and the first hydraulic pump is automatically adjusted in pump displacement according to the control valve throttle port pressure signal fed back by the front working connection.

[0026] In some embodiments, the hybrid hydraulic system comprises a controller configured to:

[0027] controlling the generator to drive the second hydraulic pump to work, and pumping pressure oil to the total oil inlet through the second pumping oil passage;

[0028] controlling the engine to drive the first hydraulic pump to work, and pressure oil pumped by the first pumping oil passage to the total oil inlet through the front working connection of the front multi-way valve;

[0029] controlling the main working connection to work;

[0030] wherein the controller is further configured to adjust the output flow of the front working connection according to the total flow demand corresponding to the control signal of each main working connection as a supplement to the output flow of the second hydraulic pump.

[0031] In some embodiments, the controller is further configured to:

[0032] determining that the supply flow is insufficient;

[0033] controlling the second hydraulic pump to automatically adjust to the maximum pump displacement according to the control valve throttle port pressure signal fed back by the main working connection;

[0034] increasing the output flow of the front working connection according to the flow control signal of each main working connection;

[0035] controlling the first hydraulic pump to increase the pump displacement according to the control valve throttle port pressure signal fed back by the front working connection.

[0036] In some embodiments, the controller is further configured to:

[0037] determining that the supply flow is excessive;

[0038] controlling the second hydraulic pump to automatically reduce the pump displacement according to the control valve throttle pressure signal fed back by the main working connection;

[0039] reducing the output flow of the front working connection according to the flow control signal of each main working connection;

[0040] controlling the first hydraulic pump to reduce the pump displacement according to the control valve throttle pressure signal fed back by the front working connection.

[0041] In some embodiments, the method further comprises:

[0042] determining that the output flow of the front working connection is not reduced;

[0043] controlling the flow control valve in the main multi-way valve to unload the excess flow.

[0044] In some embodiments, the hybrid hydraulic system comprises a controller configured to:

[0045] determining that the main multi-way valve and the front multi-way valve are in unloading state;

[0046] controlling the clutch to be engaged so that the engine drives the generator to generate electricity.

[0047] In some embodiments, the clutch is an electromagnetic clutch.

[0048] In some embodiments, the first hydraulic pump and the second hydraulic pump are electric proportional variable pumps.

[0049] In the hybrid hydraulic system provided by the present application, the engine, the first hydraulic pump, the clutch, the generator and the second hydraulic pump are coaxially connected in sequence, the conventional load-sensitive pump, the electromagnetic clutch and the load-sensitive multi-way valve can be used as the components of the hybrid hydraulic system, the power of the engine and the generator is mixed in the form of hydraulic transmission, the power mixing without mechanical coupling and impact can be easily realized, the requirements for mechanical structure and electrical control are reduced, and the load-sensitive hydraulic pump can be respectively connected to the output shaft of the engine and the output shaft of the generator, the generator is connected to the hydraulic pump mounted on the output shaft of the engine through the clutch, the hydraulic pumps mounted on the engine and the generator can work independently or in combination, and the engine can drive the generator to generate electricity.

[0050] Other features and advantages of the embodiments of the present application will be described in detail in the following specific embodiments. BRIEF DESCRIPTION OF DRAWINGS

[0051] The accompanying drawings, which are included to provide a further understanding of the embodiments and are incorporated in and constitute a part of this specification, illustrate embodiments and together with the

[0052] Figure 1 Structure diagram of power connection and transmission of a hybrid hydraulic system according to an embodiment of the present application;

[0053] Figure 2 Hydraulic principle diagram of a hydraulic source part of a hybrid hydraulic system according to an embodiment of the present application;

[0054] Figure 3 Hydraulic principle diagram of an actuator and control part of a hybrid hydraulic system according to an embodiment of the present application;

[0055] Figure 4 Structure diagram of power connection and transmission of a hybrid hydraulic system according to another embodiment of the present application;

[0056] Figure 5 Hydraulic principle diagram of an actuator and control part of a hybrid hydraulic system according to another embodiment of the present application.

[0057] BRIEF DESCRIPTION OF THE DRAWINGS

[0058] 1 engine 2 generator

[0059] 3 first hydraulic pump 4 second hydraulic pump

[0060] 5 clutch 6 front multi-way valve

[0061] 7 first check valve 8 second check valve

[0062] 9 main multi-way valve 10 travel diverter valve

[0063] 11 travel motor 12 luffing cylinder

[0064] 13 telescopic cylinder 14 balance valve

[0065] 15 pilot valve group 16 auxiliary pump

[0066] 17 auxiliary pump motor 18 connecting shaft

[0067] 21 travel link 22 luffing link

[0068] 23 telescopic link

[0069] 61 front unloading valve 62 front working link

[0070] 91 main unloading valve 92 flow control valve

[0071] L1 First Pumping Oil Circuit L2 Second Pumping Oil Circuit

[0072] D1 Total oil inlet; D2 Total oil return outlet.

[0073] D3 Feedback Port Detailed Implementation

[0074] The specific embodiments of this application will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit this application.

[0075] The hybrid hydraulic system according to this application is described below with reference to the accompanying drawings.

[0076] This application discloses a novel hybrid hydraulic system. For example... Figures 1 to 3 As shown, in one specific embodiment, the hybrid hydraulic system includes:

[0077] Engine 1, first hydraulic pump 3, clutch 5, generator 2 and second hydraulic pump 4 are connected coaxially in sequence;

[0078] The main multi-way valve 9 includes multiple main working links and a main oil inlet D1 that supplies oil to the multiple main working links;

[0079] Among them, the first pumping oil circuit L1 of the first hydraulic pump 3 and the second pumping oil circuit L2 of the second hydraulic pump 4 are connected in parallel and converge at the total oil inlet D1 of the main multi-way valve 9.

[0080] In this application, as Figure 1 As shown, the power and hydraulic source consists of an engine, a generator, a clutch, and two hydraulic pumps. The first hydraulic pump 3 is connected to the engine 1 via a coupling (i.e., connecting shaft 18) and does not need to be separated. The second hydraulic pump 4 is connected to the generator 2 via a coupling and does not need to be separated. The first hydraulic pump 3 and the generator 2 are connected to both ends of the clutch 5 via a coupling. The engine 1 and the generator 2 are transmitted through the clutch 5 and the hydraulic system, realizing the mixing of fuel power and electric power.

[0081] like Figure 3As shown, the hydraulic power of the two hydraulic pumps is output through the action connection by the main multi-way valve 9 including multiple main working connections. In this way, the power of the engine 1 and the generator 2 is mixed in a hydraulic transmission manner, and the power mixing without mechanical coupling and impact is conveniently realized, and the requirements for mechanical structure and electrical control are reduced. The hydraulic pumps are connected to the engine output shaft and the generator output shaft, respectively, and the generator 2 is connected to the first hydraulic pump 3 mounted on the engine output shaft through the clutch 5, so that the hydraulic pumps mounted on the engine 1 and the generator 2 can work independently or in combination, and the generator 2 has the functions of a motor and a generator, and can realize the switching of the motor and the generator under certain conditions, so that the engine 1 can drive the generator 2 to generate electricity, which will be described in detail below.

[0082] Referring to Figure 2 , further, the hybrid hydraulic system can include:

[0083] The front multi-way valve 6 is arranged in the first pumping oil path L1 and is used to control the output flow of the first hydraulic pump 3.

[0084] The front multi-way valve 6 includes a front working connection 62, and the working oil port of the front working connection 62 is connected to the total oil inlet D1 of the main multi-way valve 9.

[0085] In this way, the front multi-way valve 6 is used to control the output flow of the first hydraulic pump 3, and the main multi-way valve 9 is used to distribute the flow into the actuator, and when the second hydraulic pump 4 works independently, the output flow is automatically adjusted according to the total flow demand of the main multi-way valve 9.

[0086] In Figures 1 to 3 the embodiment, the first hydraulic pump 3 and the second hydraulic pump 4 are both load-sensitive hydraulic pumps capable of automatically adjusting the displacement according to the feedback pressure, so as to prevent the output overload of the pump, and the front multi-way valve 6 and the main multi-way valve 9 are both load-sensitive hydraulic multi-way valves.

[0087] The clutch 5 is preferably an electromagnetic clutch, which is convenient for combination and separation control. In addition, in order to prevent the backflow of the pumped hydraulic oil, the first pumping oil path L1 is provided with a first one-way valve 7 for preventing the backflow of the pump, the second pumping oil path L2 is provided with a second one-way valve 8 for preventing the backflow of the pump, and the first one-way valve 7 is arranged on the connecting oil path between the working oil port of the front working connection 62 and the total oil inlet D1. Moreover, in order to facilitate the removal of excess oil and ensure the safety of the system, the front multi-way valve 6 includes a front unloading valve 61, and the main multi-way valve 9 includes a main unloading valve 91.

[0088] Further, the hybrid hydraulic system of the embodiment includes a controller configured to:

[0089] The generator motor 2 drives the second hydraulic pump 4 to work, and pumps pressurized oil to the main oil inlet D1 through the second pumping oil circuit L2.

[0090] The main working link is controlled to operate, and the main working link feeds back the pressure signal of the control valve throttle port to the second hydraulic pump 4.

[0091] Control the generator 2 to operate at a constant economic speed;

[0092] The second hydraulic pump 4 automatically adjusts its pump displacement according to the total flow demand corresponding to the flow control signals of each main working link.

[0093] Combination Figure 2 , Figure 3 The generator 2 can provide power independently. At this time, the main unloading valve 91 is energized, and the hydraulic system is in a non-unloading state. The generator 2 drives the second hydraulic pump 4 to operate. The pumped oil enters the main multi-way valve 9 for flow distribution, or flows into the balance valve 14 and the travel diverter valve 10 to drive the travel motor 11 to rotate, or flows into the balance valve 14 and the luffing cylinder 12 to push the cylinder to extend or retract, or flows into the balance valve 14 and the telescopic cylinder 13 to push the cylinder to extend or retract.

[0094] When the main working linkage of the main multi-way valve 9 is activated, it will simultaneously transmit the pressure signal of the control valve throttle port to the second hydraulic pump 4 through LS2' and LS2. This pressure is a necessary condition for real-time control of the output displacement of the second hydraulic pump 4, and is used to realize the automatic adjustment of the pump displacement.

[0095] At this time, the motor can run at a constant economic speed. The action speed of each actuator is controlled by the main multi-way valve 9. The second hydraulic pump 4 automatically adjusts the displacement according to the total flow demand corresponding to the control signals of each link of the main multi-way valve 9 (i.e., the walking link 21, the luffing link 22, the telescopic link 23, etc. shown in the figure), so as to reduce energy waste.

[0096] In addition, the controller can also be configured as follows:

[0097] The engine 1 drives the first hydraulic pump 3 to work. The pressurized oil pumped through the first pumping oil circuit L1 flows to the main oil inlet D1 through the front working link 62 of the front multi-way valve 6.

[0098] The control valve 62 operates and sends a pressure signal from the control valve throttle port back to the first hydraulic pump 3.

[0099] Control engine 1 to operate at a constant, economical speed;

[0100] The controller is also configured to adjust the output flow of the front working link 62 according to the total flow demand corresponding to the flow control signal of each main working link, and the first hydraulic pump 3 automatically adjusts the pump displacement according to the control valve throttle pressure signal fed back by the front working link 62.

[0101] This is the working condition of engine power alone. The front unloading valve 61 in the front multi-way valve 6 is powered on, and the main unloading valve 91 in the main multi-way valve 9 is powered on, and the hydraulic system is in a non-unloading state.

[0102] The engine 1 drives the first hydraulic pump 3 to output hydraulic oil from the P1, P1' ports into the front multi-way valve 6, controls the front working link 62 in the front multi-way valve 6, so that the oil flows out from the A1 port, flows into the main multi-way valve 9 through the first one-way valve 7, and is distributed by the main multi-way valve 9, or flows into the balance valve 14 and the travel shunt valve 10 to drive the travel motor to rotate, or flows into the balance valve 14 and the luffing cylinder 12 to push the luffing cylinder to perform extension and retraction action.

[0103] When the front working link 62 of the front multi-way valve 6 is actuated, the control valve throttle port pressure signal will be transmitted to the first hydraulic pump 3 through LS1', LS1 at the same time. This pressure is a necessary condition for real-time control of the output displacement of the first hydraulic pump 3, and is used to realize automatic adjustment of the pump displacement.

[0104] At this time, the engine 1 can run at a constant economic speed, the output flow of the first hydraulic pump 3 is controlled by the front multi-way valve 6, and the flow is distributed by the main multi-way valve 9 according to the control signal, so as to control the action speed of each actuator. The output flow of the first hydraulic pump 3 is adjusted according to the total flow demand corresponding to the main multi-way valve 9 link control signal, and the output flow of the front multi-way valve 6 is adjusted by the control system. The first hydraulic pump 3 automatically adjusts the output flow according to the throttle port pressure signal transmitted through LS1', LS1. In this way, the output is adjusted according to the demand, so as to reduce the waste of energy consumption.

[0105] In addition, the controller is also configured to:

[0106] Control the generator 2 to drive the second hydraulic pump 4 to work, and pump pressure oil to the total oil inlet D1 through the second pumping oil way L2;

[0107] Control the engine 1 to drive the first hydraulic pump 3 to work, and the pressure oil pumped by the first pumping oil way L1 flows to the total oil inlet D1 through the front working link 62 of the front multi-way valve 6;

[0108] Control the main working link to work;

[0109] Among them, the controller is also set to adjust the output flow of the front working link 62 according to the total flow demand corresponding to the control signal of each main working link as a supplement to the output flow of the second hydraulic pump 4.

[0110] This is the working condition of the power generation motor and the internal combustion engine at the same time. The front unloading valve 61 in the multi-way valve 6 is powered on, the main unloading valve 91 in the main multi-way valve 9 is powered on, and the hydraulic system is in a non-unloading state. The engine 1 drives the first hydraulic pump 3 to output hydraulic oil from the P1, P1' port into the front multi-way valve 6, controls the front working connection 62 in the front multi-way valve 6 to make the oil flow out from the A1, and flows into the P2' oil port of the main multi-way valve 9 through the first one-way valve 7.

[0111] The main unloading valve 91 in the main multi-way valve 9 is powered on, and the hydraulic system is in a non-unloading state. The power generation motor 2 drives the second hydraulic pump 4 to output hydraulic oil, and the oil flows through the P2 port and the second one-way valve 8 into the P2' oil port of the main multi-way valve 9.

[0112] At this time, the hydraulic oil output by the first hydraulic pump 3 and the second hydraulic pump 4 flows into the total oil inlet D1 of the main multi-way valve 9, and the control system adjusts the output flow of the front working connection 62 of the front multi-way valve 6 according to the total flow demand corresponding to the control signal of each connection of the main multi-way valve 9, and the output flow of the second hydraulic pump 4 is supplemented, and after the two flows are combined, the flow is distributed by the main multi-way valve 9, or flows into the balance valve 14 and the travel distribution valve 10 to drive the travel motor to rotate, or flows into the balance valve 14 and the luffing cylinder 12 to push the luffing cylinder to perform extension and retraction action, thereby realizing hybrid power output of fuel power and electric power.

[0113] Further, the controller is further configured to:

[0114] determine that the supply flow is insufficient;

[0115] control the second hydraulic pump 4 to automatically adjust to the maximum pump displacement according to the control valve throttle pressure signal fed back by the main working connection;

[0116] adjust the output flow of the front working connection 62 according to the flow control signal of each main working connection;

[0117] control the first hydraulic pump 3 to increase the pump displacement according to the control valve throttle pressure signal fed back by the front working connection 62.

[0118] Alternatively, the controller is further configured to:

[0119] determine that the supply flow is excessive;

[0120] control the second hydraulic pump 4 to automatically reduce the pump displacement according to the control valve throttle pressure signal fed back by the main working connection;

[0121] reduce the output flow of the front working connection 62 according to the flow control signal of each main working connection;

[0122] control the first hydraulic pump 3 to reduce the pump displacement according to the control valve throttle pressure signal fed back by the front working connection 62.

[0123] Further, the output flow of the front working connection 62 is determined not to be reduced, and the flow control valve 92 in the main multi-way valve 9 is controlled to unload the excess flow.

[0124] In the working condition of the generator and the internal combustion engine providing power at the same time, when the flow is insufficient, the second hydraulic pump 4 automatically adjusts the output to the maximum according to the throttle pressure signal transmitted through LS2' and LS2. The first hydraulic pump 3 increases the output of the front working connection 62 of the front multi-way valve 6 according to the flow control signal of each connection of the main multi-way valve 9, and then automatically increases the output according to the throttle pressure signal transmitted through LS1' and LS1.

[0125] When the total flow is excessive, the second hydraulic pump 4 automatically reduces the output according to the throttle pressure signal transmitted through LS2' and LS2. The first hydraulic pump 3 reduces the output of the front working connection 62 of the front multi-way valve 6 according to the flow control signal of each connection of the main multi-way valve 9, and then automatically reduces the output according to the throttle pressure signal transmitted through LS1' and LS1. If the output flow of the working connection of the front multi-way valve 6 is not correctly reduced, the flow control valve 92 of the main multi-way valve 9 will automatically unload the excess flow back to the tank, which plays a role of unloading at a relatively low pressure and reduces energy waste to a certain extent.

[0126] In addition, the controller is further configured to:

[0127] determine that the main multi-way valve 9 and the front multi-way valve 6 are in an unloading state;

[0128] control the clutch 5 to be engaged, so that the engine 1 drives the generator 2 to generate electricity.

[0129] This is the working condition of the engine driving the generator to generate electricity. When the device actuator is idle, the hydraulic system does not work, and the control system can automatically charge the battery according to the device power.

[0130] At this time, the front unloading valve 61 in the multi-way valve 6 loses power, the main unloading valve 91 in the main multi-way valve 9 loses power, the hydraulic system is in an unloading state, and the hydraulic system has no load. The clutch 5 is engaged, and the output shaft of the engine 1 is connected to the generator 2 through the shaft of the first hydraulic pump 3 and the shaft of the clutch 5, so that the engine 1 drives the generator 2 to generate electricity and charge the device battery.

[0131] In summary, this application uses conventional load-sensitive pumps, load-sensitive multi-way valves, and electromagnetic clutches as components of the hybrid hydraulic system. The system is simple, components are readily available, and the application is mature. The transmission method of multiple hydraulic pumps converging simplifies the structure of the hybrid power system of the internal combustion engine and electric motor, reduces the requirements for the control system, and avoids complex mechanical transmission devices. Even in hybrid operation, the internal combustion engine and electric motor can still operate independently without complex speed and torque matching control, thus reducing system construction costs and failure rates from the design stage.

[0132] exist Figure 4 , Figure 5 In the embodiment shown, the first hydraulic pump 3 and the second hydraulic pump 4 are electro-proportional variable pumps. Specifically, an electro-proportional variable pump is used instead of... Figures 1 to 3 The load-sensitive pump shown can have its displacement directly adjusted by the control system based on the speed requirements of the actuator. Figure 4 An auxiliary pump 16 with a pilot valve assembly 15 was also added, driven by an auxiliary motor 17, to serve as a replenishment pump.

[0133] As is known to those skilled in the art, this can achieve greater energy savings compared to load-sensitive pump systems, although it also places slightly higher demands on the electrical control system.

[0134] In the description of this application, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0135] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between components; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0136] In the description of the specification, the description using the terms "one embodiment", "some embodiments", "an example", "a specific example", or "some examples" etc. means that the particular feature, structure, material or characteristic being described is included in at least one embodiment or example of the present application. The illustrative appearances of the above-mentioned terms in various places in the specification are not necessarily referred to the same embodiment or example. Moreover, the particular features, structures, materials, or characteristics can be combined in any suitable manner in one or more embodiments or examples. Furthermore, the terms "comprise", "comprising", "include", "including", "contain", "containing" or variations thereof are used inclusively and do not exclude the additional inclusion of unrecited features, structures, materials, or characteristics.

[0137] Although the embodiments of the present application have been shown and described above, it is understood that the above-described embodiments are exemplary and are not to be interpreted as limiting the present application, and ordinary skilled people in the art can make changes, modifications, replacements and variations to the above-described embodiments within the scope of the present application.

Claims

1. A hybrid hydraulic system, characterized by, The hybrid hydraulic system comprises: The engine (1), the first hydraulic pump (3), the clutch (5), the generator (2) and the second hydraulic pump (4) are coaxially connected in sequence; The main multi-way valve (9) comprises a plurality of main working connections and a total oil inlet (D1) for supplying oil to the plurality of main working connections; wherein the first pumping oil path (L1) of the first hydraulic pump (3) and the second pumping oil path (L2) of the second hydraulic pump (4) are connected in parallel and collected at the total oil inlet (D1) of the main multi-way valve (9), and the main multi-way valve (9) comprises a main unloading valve (91); The front multi-way valve (6) is arranged in the first pumping oil path (L1) and is used for controlling the output flow of the first hydraulic pump (3), and the front multi-way valve (6) comprises a front working connection (62) and a front unloading valve (61), and the working oil port of the front working connection (62) is connected to the total oil inlet (D1) of the main multi-way valve (9).

2. The hybrid hydraulic system of claim 1, wherein, The first pumping oil path (L1) is provided with a first one-way valve (7) for preventing pumping backflow, and the second pumping oil path (L2) is provided with a second one-way valve (8) for preventing pumping backflow, and the first one-way valve (7) is arranged on the connecting oil path between the working oil port of the front working connection (62) and the total oil inlet (D1).

3. The hybrid hydraulic system of any one of claims 1-2, wherein, The first hydraulic pump (3) and the second hydraulic pump (4) are load-sensitive hydraulic pumps capable of automatically adjusting the displacement according to the feedback pressure, and the front multi-way valve (6) and the main multi-way valve (9) are load-sensitive hydraulic multi-way valves.

4. The hybrid hydraulic system of claim 3, wherein, The hybrid hydraulic system comprises a controller configured to: Control the generator (2) to drive the second hydraulic pump (4) to work, and pump pressure oil to the total oil inlet (D1) through the second pumping oil path (L2); Control the main working connection to work, wherein the main working connection feeds back the control valve throttle port pressure signal to the second hydraulic pump (4); Control the generator (2) to operate at a constant economic speed; Wherein, the second hydraulic pump (4) automatically adjusts the pump displacement according to the total flow demand corresponding to the flow control signal of each main working connection.

5. The hybrid hydraulic system of claim 3, wherein, The hybrid hydraulic system comprises a controller configured to: Control the engine (1) to drive the first hydraulic pump (3) to work, and the pressure oil pumped through the first pumping oil path (L1) flows to the total oil inlet (D1) through the front working connection (62) of the front multi-way valve (6); Control the front working connection (62) to work, and feed back the control valve throttle port pressure signal to the first hydraulic pump (3); Control the engine (1) to operate at a constant economic speed; Wherein, the controller is further configured to adjust the output flow of the front working connection (62) according to the total flow demand corresponding to the flow control signal of each main working connection, and the first hydraulic pump (3) automatically adjusts the pump displacement according to the control valve throttle port pressure signal fed back by the front working connection (62).

6. The hybrid hydraulic system of claim 3, wherein, The hybrid hydraulic system comprises a controller configured to: controlling the generator (2) to drive the second hydraulic pump (4) to work, and pumping pressure oil to the total oil inlet (D1) through the second pumping oil path (L2); controlling the engine (1) to drive the first hydraulic pump (3) to work, and pumping pressure oil to the total oil inlet (D1) through the front working connection (62) of the front multi-way valve (6) and the first pumping oil path (L1); controlling the main working connection to work; wherein the controller is further configured to adjust the output flow of the front working connection (62) as a supplement to the output flow of the second hydraulic pump (4) according to the total flow demand corresponding to the control signal of each main working connection.

7. The hybrid hydraulic system of claim 6, wherein, The controller is further configured to: determine that the supply flow is insufficient; control the second hydraulic pump (4) to automatically adjust to the maximum pump displacement according to the control valve throttle pressure signal fed back by the main working connection; adjust the output flow of the front working connection (62) according to the flow control signal of each main working connection; control the first hydraulic pump (3) to increase the pump displacement according to the control valve throttle pressure signal fed back by the front working connection (62).

8. The hybrid hydraulic system of claim 6, wherein, The controller is further configured to: determine that the supply flow is excessive; control the second hydraulic pump (4) to automatically adjust to the maximum pump displacement according to the control valve throttle pressure signal fed back by the main working connection; adjust the output flow of the front working connection (62) according to the flow control signal of each main working connection; control the first hydraulic pump (3) to increase the pump displacement according to the control valve throttle pressure signal fed back by the front working connection (62).

9. The hybrid hydraulic system of claim 8, wherein, According to the flow control signal of each main working connection, the output flow of the front working connection (62) is further adjusted, comprising: determining that the output flow of the front working connection (62) is not adjusted; controlling the flow control valve (92) in the main multi-way valve (9) to unload the excess flow.

10. The hybrid hydraulic system of claim 3, wherein, The hybrid hydraulic system comprises a controller configured to: determine that the main multi-way valve (9) and the front multi-way valve (6) are in unloading state; control the clutch (5) to be engaged, so that the engine (1) drives the generator (2) to generate electricity.

11. The hybrid hydraulic system of claim 1, wherein, The clutch (5) is an electromagnetic clutch.

12. The hybrid hydraulic system of claim 1, wherein, The first hydraulic pump (3) and the second hydraulic pump (4) are electric proportional variable pumps.

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