Hydraulic system and working machine

Abstract

The application belongs to the field of engineering machinery and discloses a hydraulic system and a working machine. The hydraulic system comprises a motor assembly, a plurality of rotary motors connected in parallel with each other, a multi-way valve, at least a first rotary valve group connection and a second rotary valve group connection for controlling the motor assembly, and other valve group connections for controlling other actuators, and a hydraulic pump group, at least comprising a first main pump and a second main pump, both of which are open pumps. The hydraulic oil of the first main pump is pumped to the motor assembly, and the oil outlet of the second main pump is provided with a rotary pumping oil path and a parallel bypass pumping oil path. The pumped hydraulic oil of the second main pump can be supplied to the motor assembly through the second rotary valve group connection and / or supplied to other actuators through other valve group connections. When the rotary motor operates independently, the rotary motor can be supplied by a plurality of rotary pumps, thereby improving the rotary speed. When the motor assembly performs a composite action, the second main pump can supply part of the hydraulic oil to other actuators, thereby realizing controllable rotary speed and avoiding the influence of other actuators.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of engineering machinery, and in particular relates to a hydraulic system and a working machine. BACKGROUND

[0002] Large-tonnage excavators have high requirements for the coordination between various actions during loading operations. In order to balance the excavator between the rotation action and the action of the working device execution element, the prior art mostly uses a closed system to set a special main pump for the rotation motor, thereby achieving independent control. However, the setting of such a special main pump inevitably causes performance waste. In addition, there is also a way of adding a merging valve, that is, a merging valve is set in front of the main valve, and the pumped hydraulic oil of multiple main pumps is merged to the main valve through the merging valve, and then the priority during the rotation action is realized by program control of the main valve core opening, so as to realize flow distribution. In this case, although the priority function can be realized, the change of the load easily causes the change of the flow distribution, so that the priority effect dynamically changes, causing the instability of the operation coordination SUMMARY

[0003] The purpose of the present application is to provide a hydraulic system and a working machine to improve the control performance of the rotation action, improve the efficiency, and save energy consumption.

[0004] To achieve the above purpose, the present application provides a hydraulic system applied to a working machine, the hydraulic system comprising:

[0005] a motor assembly comprising multiple rotation motors connected in parallel with each other;

[0006] a multi-way valve comprising at least a first rotation valve group connection and a second rotation valve group connection for controlling the motor assembly and other valve group connections for controlling other execution mechanisms;

[0007] a hydraulic pump group comprising at least a first main pump and a second main pump, both of which are open pumps, pumped hydraulic oil of the first main pump is pumped to the motor assembly through the first rotation valve group connection, an oil outlet of the second main pump is provided with a rotation pumping oil path connected to the second rotation valve group connection and a bypass pumping oil path connected to the other valve group connections in parallel with the rotation pumping oil path, pumped hydraulic oil of the second main pump can be supplied to the motor assembly through the second rotation valve group connection and / or supplied to the other execution mechanisms through the other valve group connections.

[0008] In some embodiments, the hydraulic system comprises:

[0009] a first logical priority valve arranged in the rotation pumping oil path and used for controlling the flow rate of the rotation pumping oil path;

[0010] A second logic priority valve is arranged in the bypass pumping oil line and used to control the flow rate of the bypass pumping oil line.

[0011] In some embodiments, the first and second logic priority valves are structurally identical and each comprises a cartridge valve and a hydraulic cylinder for driving the cartridge valve spool to move. And / or, the first and second main pumps are variable pumps; and / or, the second main pump is multiple, and the hydraulic pump group further comprises other main pumps for supplying oil to the other actuators

[0012] In some embodiments, the hydraulic system comprises a main pilot oil line, the first and second logic priority valves are both pilot operated valves, the pilot port of the first logic priority valve is selectively connected to the main pilot oil line or hydraulic return through a first logic solenoid valve, and the pilot port of the second logic priority valve is selectively connected to the main pilot oil line or hydraulic return through a second logic solenoid valve; wherein the first and second rotary valve banks are both pilot operated directional control valves, the pilot port of the first rotary valve bank is selectively connected to the main pilot oil line or hydraulic return through a first pilot solenoid valve, and the pilot port of the second rotary valve bank is selectively connected to the main pilot oil line or hydraulic return through a second pilot solenoid valve.

[0013] In some embodiments, the first and second logic solenoid valves and the first and second pilot solenoid valves are all proportional solenoid valves controlled by an operating handle.

[0014] In some embodiments, the hydraulic system comprises:

[0015] A first on-off solenoid valve through which the pilot hydraulic oil of the main pilot oil line flows to the first and second pilot solenoid valves;

[0016] A second on-off solenoid valve through which the pilot hydraulic oil of the main pilot oil line flows to the motor brake oil line of the motor assembly.

[0017] In some embodiments, the hydraulic pump group further comprises:

[0018] A pilot pump for supplying oil to the main pilot oil line;

[0019] A pilot accumulator hydraulically connected to the main pilot oil line.

[0020] In some embodiments, a first one-way valve as a back pressure valve is arranged in the first return oil port oil path of the first rotary valve group, a second one-way valve as a back pressure valve and a radiator relatively close to the hydraulic oil tank are arranged in series in the second return oil port oil path of the second rotary valve group, and the valve port end of the first one-way valve is in hydraulic communication with the valve port end of the second one-way valve through a connecting pipeline; wherein the back pressure of the first one-way valve is greater than the back pressure of the second one-way valve.

[0021] In addition, the application also provides a working machine comprising the above hydraulic system.

[0022] In some embodiments, the working machine is an ultra-large excavator with a self weight not less than 100 tons.

[0023] In the hydraulic system and the working machine of the application, the rotary motors are connected in parallel with each other and driven by an open pump, the pumped hydraulic oil of the second main pump can be supplied to the motor assembly through the second rotary valve group and / or supplied to other actuators through other valve groups, so that in actual work, when a single rotary action is performed, the rotary motors can be supplied by a single main pump or supplied by multiple rotary pumps together, so that the rotary speed can be improved; when a compound action is performed, the rotary motors can be supplied by the first main pump alone, and the second main pump and the remaining main pumps can supply other actuators together, so that the rotary speed is controllable and is not affected by other actuators, thus improving the control performance of the rotary action and saving energy.

[0024] Other advantages of the application and technical effects of the preferred embodiments will be further described in the following specific embodiments. BRIEF DESCRIPTION OF DRAWINGS

[0025] The accompanying drawings are included to provide a further understanding of the application and constitute a part of the specification, and together with the following specific embodiments, serve to explain the application but do not constitute a limitation of the application. In the drawings:

[0026] Figure 1 is a schematic diagram of the hydraulic system according to the specific embodiments of the application;

[0027] Figure 2 is a hydraulic principle diagram of the hydraulic system according to the specific embodiments of the application;

[0028] Figure 3 is an enlarged display of the multi-way valve part in Figure 2 ; and

[0029] Figure 4 is an enlarged display of the motor assembly part in Figure 2 .

[0030] REFERENCE NUMERALS

[0031] 1 engine 2 first main pump

[0032] 3 second main pump 4 pilot pump

[0033] 5 first main relief valve 6 pilot relief valve

[0034] 7 second main relief valve 8 first rotary valve group

[0035] 9 second rotary valve group 10 motor assembly

[0036] 11 first pilot solenoid valve 12 second pilot solenoid valve

[0037] 13 solenoid valve group 14 pilot accumulator

[0038] 16 first check valve 17 second check valve

[0039] 18 radiator 19 filter

[0040] 20 hydraulic oil tank 21 connecting pipeline

[0041] 22 other valve group

[0042] 101 first rotary motor 102 second rotary motor

[0043] 131 first on-off solenoid valve 132 second on-off solenoid valve

[0044] 133 second logic solenoid valve 134 first logic solenoid valve

[0045] 151 first logic priority valve 152 second logic priority valve

[0046] L1 rotary pumping oil path L2 bypass pumping oil path

[0047] T1 first return port oil path T2 second return port oil path DETAILED DESCRIPTION

[0048] The specific embodiments of the present application will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are merely intended to illustrate and explain the present application, and are not intended to limit the present application. It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict.

[0049] The working machine and the hydraulic system thereof will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0050] The present application discloses a brand-new hydraulic system applied to a working machine. Referring to Figures 2 to 4In one specific embodiment, the new hydraulic system comprises:

[0051] The motor assembly 10 comprises a plurality of swing motors connected in parallel with each other;

[0052] The multi-way valve comprises at least a first swing valve group 8 and a second swing valve group 9 for controlling the motor assembly 10, and other valve groups 22 for controlling other actuators;

[0053] The hydraulic pump group comprises at least a first main pump 2 and a second main pump 3, both of which are open pumps, the first main pump 2 pumps hydraulic oil to the motor assembly 10 through the first swing valve group 8, and the second main pump 3 has an outlet connected to a swing pumping oil path L1 of the second swing valve group 9 and a bypass pumping oil path L2 connected to the other valve groups 22 in parallel with the swing pumping oil path L1, and the second main pump 3 can pump hydraulic oil to the motor assembly 10 through the second swing valve group 9 and / or to the other actuators through the other valve groups 22.

[0054] In this application, the motor assembly 10 comprises a plurality of swing motors connected in parallel with each other, so that Figure 4 For example, it comprises a first swing motor 101 and a second swing motor 102, both of which are connected in parallel with each other, i.e. the pumping hydraulic oil of the outlet of a single swing valve group can flow to both motors at the same time to drive both motors to rotate. Of course, the motor assembly 10 is not limited to the two motors shown in the figure, and can comprise more in parallel. Similarly, the multi-way valve can also comprise more swing valve groups, and the other valve groups 22 can be one or more.

[0055] The working machine described below takes an excavator as an example. Referring to Figure 1 Taking a super-large excavator as an example, it can have a plurality of main pumps to drive actuators such as travel motors, swing motors, boom cylinders, stick cylinders, bucket cylinders, etc. Due to the large number and dispersion of actuators, the required hydraulic flow is large, so the number of main pumps is large, and the multi-way valve can also comprise a main valve group and a secondary valve group, etc. to control each main pump and the corresponding actuator respectively. It should be noted that the motor assembly 10 in this application comprises a plurality of swing motors connected in parallel with each other, and the swing motor is relative to a linear motor, etc., which refers to a motor for driving an actuator to rotate, so Figure 1 The travel motor in

[0056] In Figure 2In the shown embodiment, on the basis of two parallel rotary motors, the multi-way valve is correspondingly provided with two rotary valve groups, and the hydraulic pump group comprises two main pumps, which are both open pumps. The pumped hydraulic oil of the first main pump 2 can drive the two rotary motors through the first rotary valve group 8, and at least part of the pumped hydraulic oil of the second main pump 3 can also drive the two rotary motors through the second rotary valve group 9 along the rotary pumping oil path L1, and the two rotary motors can be independently driven or jointly driven. At least part of the pumped hydraulic oil of the second main pump 3 can also drive other actuators (not shown in the figure) through the bypass pumping oil path L2.

[0057] Thus, when the excavator performs a single rotary action, the rotary motor can be driven by a single main pump or by two main pumps, so as to improve the rotary speed and the flexible control performance of the rotary action, and the rotary driving main pump can be controlled to work at high efficiency and save energy. When the excavator performs a composite action, one main pump can independently supply oil to the rotary motor, and the other main pump can supply oil to other actuators together with the remaining main pumps, so as to realize controllable rotary speed and outstanding rotary control performance.

[0058] Comparatively, in the closed rotary system in the prior art, a dedicated main pump is arranged for the rotary motor, and the main pump has the following disadvantages: if a high-power main pump is used, the pump cannot exert most of its performance when the rotary speed demand is low, which results in performance waste and pump chamber space waste, especially for super-large excavators with limited space for the main pump. If a low-power main pump is used, the rotary speed adjustment range is small, and the rotary speed demand cannot be met when the demand is high. If the joint flow technology is used, that is, multiple main pumps are jointly supplied to the main valve in advance, and then the priority of the rotary action is realized by controlling the opening degree of the main valve core, the priority function can be realized, but the flow distribution is easily changed due to the change of the load. According to the energy law that "water flows to the low place", the hydraulic oil flows to the actuator with low pressure, so that the priority effect dynamically changes, and the operation coordination is unstable.

[0059] Unlike the existing closed rotary hydraulic system, the open hydraulic system is adopted in the present application, and the rotary main pumps are all open pumps, and the first and second main pumps can independently or jointly supply oil to the motor assembly. Unlike the joint flow mode in which a joint flow valve is arranged before the main valve, the joint flow is realized in the motor circuit after the main valve in the present application, rather than before the main valve.

[0060] It should be noted that, in the present application, Figure 2In the illustrated embodiment, the first main pump 2 pumps all the hydraulic oil to the motor assembly 10. But in other embodiments, the first main pump 2 can also supply oil to other actuators, i.e. the outlet of the first main pump 2 is also provided with a bypass pumping oil path L2 connected to the other valve group 22. Such an embodiment in which the first main pump 2 and the second main pump 3 have the same structure and function is also within the scope of protection of the present application.

[0061] From Figure 2 , Figure 3 it can be seen that the first main pump 2 and the second main pump 3 are both variable pumps, which can be adjusted according to the load and speed requirements of the swing motor 10 to save pumping energy. But obviously, the first main pump 2 and the second main pump 3 can also be gear pumps, etc. Among them, the second main pump 3 is not limited to one as illustrated, but can also be multiple, and the same applies to the first main pump 2. Referring to Figure 1 , the hydraulic pump group can also include one or more other main pumps for supplying oil to other actuators.

[0062] In the present embodiment, the hydraulic system further includes a logic priority valve for flow distribution logic and priority control of the pumped hydraulic oil between the swing pumping oil path L1 and the bypass pumping oil path L2. In the embodiment of Figure 2 , Figure 3 , the logic priority valve includes a first logic priority valve 151 arranged in the swing pumping oil path L1 and used to control the flow rate of the swing pumping oil path L1, and a second logic priority valve 152 arranged in the bypass pumping oil path L2 and used to control the flow rate of the bypass pumping oil path L2. The arrangement of the logic priority valve can control the priority pumping direction of the pumped hydraulic oil of the illustrated second main pump 3, i.e. the priority flow direction to the swing pumping oil path L1 or to the bypass pumping oil path L2. The first logic priority valve 151 and the second logic priority valve 152 are used for flow rate control in the oil path, so that the priority flow direction of the oil can be controlled. Of course, the logic priority valve is not limited to the flow control valve illustrated in the present embodiment, but can also be a pressure control valve, etc.

[0063] In the embodiment of Figure 2 , Figure 3 , as an example, the first logic priority valve 151 and the second logic priority valve 152 have the same structure and each include a cartridge valve and a hydraulic cylinder for driving the cartridge valve spool to move. Among them, the cartridge valve has a large flow rate, which can meet the maximum flow demand of the oil path, and the cartridge valve spool is driven to move by the hydraulic cylinder, so as to control the opening degree of the valve port of the cartridge valve, and further control the flow rate of the oil path. Those skilled in the art can know that the driving mechanism of the cartridge valve spool can also be an electric push rod, etc., and is not limited to a hydraulic cylinder.

[0064] The hydraulic system of the present application can include a main pilot oil circuit, Figure 2 、 Figure 3 The pilot pump 4 is used to supply oil to the main pilot oil circuit. A large-tonnage excavator can independently set the pilot pump 4, and the oil supply is large and stable, so that the flow and pressure of the pilot oil are more stable and controllable. Of course, the hydraulic oil of the main pilot oil circuit can also be introduced from other main pumps.

[0065] In the present embodiment, a separate pilot pump 4 is provided to supply pilot control oil to the hydraulic system, the pilot pressure is determined by the pilot relief valve 6, and the specific logic function is realized by the solenoid valve group 13 and the pilot solenoid valve. The working pressure of the swing motor is determined by the relief valve carried by the swing motor itself, and the working pressure of other actuators can be determined by the first main relief valve 5 and the second main relief valve 7.

[0066] After having an independent pilot oil source, the first logic priority valve 151 and the second logic priority valve 152 are both used as hydraulic control valves. The hydraulic control end of the first logic priority valve 151 is selectively connected to the main pilot oil circuit or the hydraulic return through the first logic solenoid valve 134, and the hydraulic control end of the second logic priority valve 152 is selectively connected to the main pilot oil circuit or the hydraulic return through the second logic solenoid valve 133. Referring to Figure 3 , the pilot pump 4 pumps the pilot oil, which flows to the first logic priority valve 151 after passing through the first logic solenoid valve 134, drives the hydraulic cylinder in the first logic priority valve 151, and thus pushes the cartridge valve spool to move, adjusts the flow and flow distribution priority of the hydraulic oil pumped by the second main pump 3 to the swing pumping oil circuit L1. It can be seen that through the hydraulic control pilot mode independent of the hydraulic circuits of other actuators, the spool opening control of the swing valve group is not affected by other valve group 22, i.e. not affected by the load of other actuators, and the swing speed is controllable.

[0067] Similarly, the first swing valve group 8 and the second swing valve group 9 shown in the figure both use hydraulic control reversing valves. The hydraulic control end of the first swing valve group 8 is selectively connected to the main pilot oil circuit or the hydraulic return through the first pilot solenoid valve 11, and the hydraulic control end of the second swing valve group 9 is selectively connected to the main pilot oil circuit or the hydraulic return through the second pilot solenoid valve 12. The pilot solenoid valve can be arranged at one end or both ends of the swing valve group. In the present embodiment, as an example, the first pilot solenoid valve 11 is arranged at both ends of the first swing valve group 8, and the second pilot solenoid valve 12 is arranged at both ends of the second swing valve group 9, so that the movement of the valve spool of the valve group can be more conveniently, quickly and accurately controlled through the pilot solenoid valves at both ends, and is not affected by the load of other actuators.

[0068] In particular, the first logic solenoid valve 134, the second logic solenoid valve 133, the first pilot solenoid valve 11 and the second pilot solenoid valve 12 in the embodiment are all proportional solenoid valves controlled by the operating handle. By controlling the angle of the operating handle of the excavator, different currents are given to the pilot solenoid valves, and the pilot solenoid valves output different pressures, so that the spools of the first and second rotary valve groups 8 and 9 realize different flow outputs, and different rotary speeds are obtained. Similarly, by controlling the angle of the operating handle, different currents are given to the first and second logic solenoid valves 134 and 133, and the logic solenoid valves output different pressures, and then the spools of the first and second logic priority valves 151 and 152 realize different flow outputs through the hydraulic cylinders, so that the flow distribution of the pumped hydraulic oil of the second main pump 3 to the rotary pumping oil circuit L1 and the bypass pumping oil circuit L2 is realized.

[0069] In the embodiment, as shown in Figure 3 The electromagnetic valve group 13 further comprises:

[0070] The first switch solenoid valve 131, through which the pilot hydraulic oil of the main pilot oil circuit flows to the first and second pilot solenoid valves 11 and 12;

[0071] The second switch solenoid valve 132, through which the pilot hydraulic oil of the main pilot oil circuit flows to the motor brake oil circuit of the motor assembly 10.

[0072] The first switch solenoid valve 131 is integrated in the electromagnetic valve group 13 and used as a safety valve. Only when the switch solenoid valve is turned on, the first and second pilot solenoid valves 11 and 12 can control the spools of the rotary valve groups. Similarly, the second switch solenoid valve 132 is also used as a safety valve, which can guide the hydraulic oil of the pilot pump 4 to the motor brake oil circuit, thereby releasing the brake of the rotary motor.

[0073] In the embodiment, the hydraulic pump group further comprises a pilot accumulator 14, which is hydraulically connected to the main pilot oil circuit, i.e. the accumulator is arranged beside the first switch solenoid valve 131, which can realize the oil supplementing and pressure stabilizing of the main pilot oil circuit when the valve spool of the reversing valve operates.

[0074] In terms of oil return of the motor assembly 10, the first oil return port oil circuit T1 of the first rotary valve group 8 is provided with a first check valve 16 as a back pressure valve, and the second oil return port oil circuit T2 of the second rotary valve group 9 is provided with a second check valve 17 as a back pressure valve and a radiator 18 relatively close to the hydraulic oil tank 20 in series; the valve port end of the first check valve 16 and the valve port end of the second check valve 17 are hydraulically connected through a connecting pipeline 21; wherein the back pressure of the first check valve 16 is greater than that of the second check valve 17.

[0075] The control oil output by the pilot pump 4 is applied to the first rotary valve group connection 8 and the second rotary valve group connection 9 through the electromagnetic valve group 13, the first pilot electromagnetic valve 11 and the second pilot electromagnetic valve 12, so that different amounts of hydraulic oil are distributed to the rotary motor under different working conditions. The low-pressure hydraulic oil after the rotary motor first passes through the oil return ports of the first rotary valve group connection 8 and the second rotary valve group connection 9, flows to the first oil return port oil path T1 and the second oil return port oil path T2, and the hydraulic oil passing through the first check valve 16 directly passes through the filter 19 to return to the hydraulic oil tank 20, and the hydraulic oil passing through the second check valve 17 first passes through the radiator 18 and then passes through the filter 19 to return to the hydraulic oil tank 20.

[0076] As can be seen, the high-pressure oil output by the main pump is distributed through the main valve, and after work from the rotary motor, becomes low-pressure oil, including low-pressure oil returned from other actuators, which can pass through the main valve to the first check valve 16 and the second check valve 17, and then pass through the radiator 18 and the filter 19 to return to the hydraulic oil tank 20. Among them, the back pressure of the first check valve 16 is greater than that of the second check valve 17, which ensures that the hydraulic oil heated after work is preferentially passed through the radiator 18 to cool the hydraulic system. And when the oil reaches a certain amount, the two check valves will simultaneously pass oil due to the increase in pipeline pressure, improving the oil return efficiency and not forming pressure.

[0077] Among them, referring to Figure 3 , the oil outlet of the first main pump 2 can be connected to the first oil return port oil path T1 after passing through the neutral position of the first rotary valve group connection 8 and the neutral position of the corresponding other valve group connection 22 in turn. Similarly, the oil outlet of the second main pump 3 can be connected to the second oil return port oil path T2 after passing through the neutral position of the second rotary valve group connection 9 and the neutral position of the corresponding other valve group connection 22 in turn. As can be seen, when the rotary valve group connection and the other valve group connection are not working and are in the neutral position, the pumped hydraulic oil of the main pump can pass through the neutral positions of the two valve group connections in turn and pass through the corresponding first oil return port oil path T1 and the second oil return port oil path T2 to return. When any one of the rotary valve group connection and the other valve group connection is working, the pumped oil of the main pump can only be pumped to the actuator in the working state.

[0078] In addition, the first oil return port oil path T1 and the second oil return port oil path T2 are also connected with a supplement oil path, which is connected to the working oil path of the rotary motor. As shown in Figure 1 , one end of the supplement oil path is connected to the first oil return port oil path T1 or the second oil return port oil path T2, and the other end is connected to the oil path at both ends of the motor through a check valve. Once the oil is lacking in the low-pressure side oil path, a vacuum suction will be formed to supplement the oil from the oil return port oil path, the supplement oil path and the check valve to the low-pressure side of the motor.

[0079] This application also discloses a working machine including the aforementioned hydraulic system. The working machine is not limited to the excavator described above, but can be any large machine equipped with a rotary motor, such as a large crawler crane. In this embodiment, the working machine is an ultra-large excavator with a self-weight of not less than 100 tons. This ultra-large excavator possesses, as... Figure 1 The multiple motors, cylinders, etc., shown also require multiple main pumps, leading to issues with oil supply distribution and motion coordination. This application, by redesigning the hydraulic system's slewing pipeline and control logic, allows two main pumps to supply oil together when the excavator performs a single slewing motion, increasing the slewing speed. When the excavator performs compound movements, one main pump can supply oil to the slewing motor alone, while the other main pump, along with the remaining main pumps, supplies oil to other actuators, achieving controllable slewing speed unaffected by other actuators. This hydraulic system also includes a logic priority valve, which assists in prioritizing the actuators during compound movements, and the priority level can be adjusted. This improves the coordination of excavator operation, enabling the operator to perform high-value work more efficiently.

[0080] By setting a logic priority valve in the main valve and combining it with the solenoid valve group 13, a certain degree of mutual priority can be achieved between actuators. When the first logic priority valve 151, located before the rotary coupling, is controlled by the first logic solenoid valve 134, other actuators can be given priority over the rotary function. When the second logic priority valve 152, located after the rotary coupling, is controlled by the second logic solenoid valve 133, the rotary function can be given priority over other actuators. Furthermore, the actuator before which the logic priority valve is located is not given priority, and the proportional solenoid valves receive different currents, resulting in different levels of priority (i.e., different priorities in flow distribution).

[0081] It should be noted that the embodiments described in conjunction with the accompanying drawings are merely examples and do not impose any restrictions on the number of main pumps, rotary valve groups, and rotary motors involved in rotary control; any form of distributing hydraulic oil from other actuators to the rotary motor at a certain time period by setting flow distribution valves, as well as adding or reducing the number of logic priority valves at any location, and the form of logic priority valves, are all alternative solutions and fall within the scope of protection of this application.

[0082] 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.

[0083] In this application, unless otherwise explicitly specified and limited, the terms "mounting", "connection", "connecting", "fixing" and the like should be understood in a broad sense, for example, can be fixed connection, can also be detachable connection, or integral; can be mechanical connection, can also be electrical connection or communication with each other; can be directly connected, can also be indirectly connected through an intermediate medium, can be the internal communication of two elements or the interaction relationship between two elements, unless otherwise explicitly limited. For those skilled in the art, the specific meaning of the above terms in this application can be understood according to the specific circumstances.

[0084] In the description of the present specification, the description of the terms "one embodiment", "some embodiments", "example", "specific example" or "some examples" and the like means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In the present specification, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any appropriate manner in any one or more embodiments or examples. Furthermore, the skilled in the art can combine and combine the different embodiments or examples described in the present specification and the features of the different embodiments or examples without contradiction.

[0085] Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limiting the present application, and those skilled in the art can make changes, modifications, replacements and variations to the above embodiments within the scope of the present application.

Claims

1. A hydraulic system applied to a work machine, characterized by, The hydraulic system comprises: a motor assembly (10) comprising a plurality of rotary motors connected in parallel with each other; a multi-way valve comprising at least a first rotary valve group (8) and a second rotary valve group (9) for controlling the motor assembly (10) and other valve groups (22) for controlling other actuators; a hydraulic pump group comprising at least a first main pump (2) and a second main pump (3) which are both open pumps, the first main pump (2) pumps hydraulic oil to the motor assembly (10) through the first rotary valve group (8), the second main pump (3) has a rotary pumping oil path (L1) connected to the second rotary valve group (9) and a bypass pumping oil path (L2) connected to the other valve groups (22) in parallel with the rotary pumping oil path (L1), the second main pump (3) can pump hydraulic oil to the motor assembly (10) through the second rotary valve group (9) and / or to the other actuators through the other valve groups (22); a first logic priority valve (151) arranged in the rotary pumping oil path (L1) and used for controlling the flow rate of the rotary pumping oil path (L1); a second logic priority valve (152) arranged in the bypass pumping oil path (L2) and used for controlling the flow rate of the bypass pumping oil path (L2); wherein the first logic priority valve (151) and the second logic priority valve (152) are of the same structure and each comprise a cartridge valve and a hydraulic cylinder for driving the cartridge valve spool to move.

2. The hydraulic system of claim 1, wherein, The first main pump (2) and the second main pump (3) are both variable pumps; and / or, the second main pump (3) is multiple, and the hydraulic pump group further comprises other main pumps for supplying oil to the other actuators.

3. The hydraulic system of claim 1, wherein, The hydraulic system comprises a main pilot oil path, the first logic priority valve (151) and the second logic priority valve (152) are both pilot operated valves, the pilot end of the first logic priority valve (151) is selectively connected to the main pilot oil path or hydraulic return through a first logic solenoid valve (134), and the pilot end of the second logic priority valve (152) is selectively connected to the main pilot oil path or hydraulic return through a second logic solenoid valve (133); wherein the first rotary valve group (8) and the second rotary valve group (9) are both pilot operated directional control valves, the pilot end of the first rotary valve group (8) is selectively connected to the main pilot oil path or hydraulic return through a first pilot solenoid valve (11), and the pilot end of the second rotary valve group (9) is selectively connected to the main pilot oil path or hydraulic return through a second pilot solenoid valve (12).

4. The hydraulic system of claim 3, wherein, The first logic solenoid valve (134), the second logic solenoid valve (133), the first pilot solenoid valve (11) and the second pilot solenoid valve (12) are all proportional solenoid valves controlled by an operating handle.

5. The hydraulic system of claim 3, wherein, The hydraulic system comprises: a first on-off solenoid valve (131), the pilot hydraulic oil of the main pilot oil path flows to the first pilot solenoid valve (11) and the second pilot solenoid valve (12) through the first on-off solenoid valve (131); A second switch electromagnetic valve (132) through which the pilot hydraulic oil of the main pilot oil passage flows to a motor brake oil passage of the motor assembly (10).

6. The hydraulic system of claim 3, wherein, The hydraulic pump set further comprises: A pilot pump (4) for supplying oil to the main pilot oil passage; A pilot accumulator (14) hydraulically connected to the main pilot oil passage.

7. The hydraulic system according to any one of claims 1 to 6, characterized in that A first return port oil passage (T1) of the first rotary valve group (8) is provided with a first check valve (16) as a back pressure valve, a second return port oil passage (T2) of the second rotary valve group (9) is provided with a second check valve (17) as a back pressure valve and a radiator (18) relatively close to a hydraulic oil tank (20) in series, a valve port end of the first check valve (16) and a valve port end of the second check valve (17) are hydraulically connected through a connecting pipeline (21); wherein the back pressure of the first check valve (16) is greater than the back pressure of the second check valve (17).

8. A work machine characterized by, The work machine comprises the hydraulic system according to any one of claims 1-7.

9. A work machine according to claim 8, characterised in that The work machine is an ultra-large excavator with a self weight not less than 100 tons.

Images