CN111691492A - Hydraulic system of excavator and excavator - Google Patents
Hydraulic system of excavator and excavator Download PDFInfo
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- CN111691492A CN111691492A CN202010611285.8A CN202010611285A CN111691492A CN 111691492 A CN111691492 A CN 111691492A CN 202010611285 A CN202010611285 A CN 202010611285A CN 111691492 A CN111691492 A CN 111691492A
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- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02F—DREDGING; SOIL-SHIFTING
- E02F9/00—Component parts of dredgers or soil-shifting machines, not restricted to one of the kinds covered by groups E02F3/00 - E02F7/00
- E02F9/20—Drives; Control devices
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- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02F—DREDGING; SOIL-SHIFTING
- E02F9/00—Component parts of dredgers or soil-shifting machines, not restricted to one of the kinds covered by groups E02F3/00 - E02F7/00
- E02F9/20—Drives; Control devices
- E02F9/22—Hydraulic or pneumatic drives
-
- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02F—DREDGING; SOIL-SHIFTING
- E02F9/00—Component parts of dredgers or soil-shifting machines, not restricted to one of the kinds covered by groups E02F3/00 - E02F7/00
- E02F9/20—Drives; Control devices
- E02F9/22—Hydraulic or pneumatic drives
- E02F9/2217—Hydraulic or pneumatic drives with energy recovery arrangements, e.g. using accumulators, flywheels
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- Engineering & Computer Science (AREA)
- Mining & Mineral Resources (AREA)
- Civil Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Structural Engineering (AREA)
- Operation Control Of Excavators (AREA)
- Fluid-Pressure Circuits (AREA)
Abstract
The invention discloses a hydraulic system of an excavator and the excavator. The hydraulic system of the excavator comprises a power unit, a main valve, a pilot valve and a pilot oil source valve group, wherein the power unit comprises a main pump and a pilot pump, the main valve is provided with a first unloading oil way, a first throttling hole is formed in the first unloading oil way, the pilot oil source valve group is provided with an oil inlet connected with the pilot pump, an unloading oil port connected with the first unloading oil way of the main valve, a first oil outlet connected with the pilot valve and an oil outlet connected with an oil tank, the oil inlet is communicated with the unloading oil port, the pilot oil source valve group comprises a first control valve arranged between the oil inlet and the first oil outlet and a second unloading oil way arranged between the oil inlet and the oil outlet, and in a first working state, oil in the oil inlet flows to the first oil outlet through the first control valve; and in a second working state, at least part of oil in the oil inlet returns to the oil tank through a second unloading oil way. The second unloading oil way of the hydraulic system is unloaded, so that energy waste is reduced.
Description
Technical Field
The invention relates to the technical field of engineering machinery, in particular to a hydraulic system of an excavator and the excavator.
Background
In recent years, with the continuous development and maturity of the excavator market, the market has higher and higher requirements on the economy and the energy conservation of vehicles. In order to improve the economy and energy conservation of vehicles, in the aspect of matching of engines and hydraulic systems, the competition of research and development of various core technologies and application of control technologies in various large host plants is intensified day by day, so that the efficiency of the hydraulic systems is continuously improved. However, the research and development of various large main engine plants mainly focus on the main pump and high-pressure oil, and the energy conservation of the pilot pump is not paid much attention. The problem of energy waste caused by the problem of pressure build-up heating of the pilot pump after the excavator is started and before the safety handle is opened is not solved all the time.
Disclosure of Invention
The invention aims to provide a hydraulic system of an excavator and the excavator, so as to solve the problem of energy waste of a pilot pump.
A first aspect of the present invention provides a hydraulic system of an excavator, including:
the power unit comprises a main pump and a pilot pump;
the main valve is provided with a first unloading oil way, and a first throttling hole is arranged on the first unloading oil way;
a pilot valve; and
the pilot oil source valve group comprises a first control valve arranged between the oil inlet and the first oil outlet and a second unloading oil path arranged between the oil inlet and the oil outlet, and in a first working state, oil in the oil inlet flows to the first oil outlet through the first control valve; and in a second working state, at least part of oil in the oil inlet returns to the oil tank through a second unloading oil way.
In some embodiments, the first control valve has a first port connected to the oil inlet, a second port connected to the oil outlet, and a third port connected to the first oil outlet, and the second unloading port is connected to the oil outlet through the first control valve, and the third port selectively communicates with the first port and the second port to switch the pilot oil source valve set between the first operating state and the second operating state.
In some embodiments, the hydraulic system further includes an accumulator connected to the first oil port of the first control valve and connected to the oil inlet of the pilot oil source valve group through an oil inlet check valve.
In some embodiments, the second relief oil passage includes a relief check valve.
In some embodiments, the second unloading oil path further comprises a second throttling hole arranged between the unloading one-way valve and the oil drain port, a first end of the second throttling hole is connected with the unloading one-way valve, a second end of the second throttling hole is connected with the first oil outlet and is connected with the oil drain port through a first control valve, and the opening degree of the second throttling hole is larger than that of the first throttling hole.
In some embodiments, the opening degree of the second throttle hole is adjustably set; alternatively, the hydraulic system comprises at least two throttle devices provided with second throttle holes, and the opening degrees of the second throttle holes of the at least two throttle devices are different and are arranged in an exchangeable manner.
In some embodiments, the second unloading oil path comprises an on-off valve, an oil inlet of the on-off valve is connected with an oil inlet of the pilot oil source valve group, an oil outlet of the on-off valve is connected with an oil outlet, and an oil inlet of the on-off valve and an oil outlet of the on-off valve can be arranged in an on-off mode.
In some embodiments, the first control end of the on-off valve is connected with the oil inlet thereof, the second control end of the on-off valve is connected with the first oil outlet and is provided with a spring, and the oil pressure of the first control end of the on-off valve and the oil pressure of the second control end of the on-off valve control the on-off of the on-off valve.
In some embodiments, the first control valve is a solenoid valve and is controlled by a safety handle.
In some embodiments, the hydraulic system further includes a travel motor, the main valve has a boost control port, the pilot oil source valve group further has a second oil outlet connected with the boost control port and a third oil outlet connected with the travel motor and includes a second control valve disposed between the oil inlet and the second oil outlet and a third control valve disposed between the oil inlet and the third oil outlet.
A second aspect of the invention provides an excavator comprising a hydraulic system as in any one of the first aspects of the invention.
Based on the technical scheme provided by the invention, the hydraulic system of the excavator comprises a power unit, a main valve, a pilot valve and a pilot oil source valve bank, wherein the power unit comprises a main pump and a pilot pump, the main valve is provided with a first unloading oil way, a first throttling hole is arranged on the first unloading oil way, the pilot oil source valve bank is provided with an oil inlet connected with the pilot pump, an unloading oil port connected with the first unloading oil way of the main valve, a first oil outlet connected with the pilot valve and an oil outlet connected with an oil tank, the oil inlet is communicated with the unloading oil port, the pilot oil source valve bank comprises a first control valve arranged between the oil inlet and the first oil outlet and a second unloading oil way arranged between the oil inlet and the oil outlet, and in a first working state, oil of the oil inlet flows to the first oil outlet through the first control valve; and in a second working state, at least part of oil in the oil inlet returns to the oil tank through a second unloading oil way. When the safety handle is closed after the engine of the excavator is started, the pilot oil source valve group is in the second working state, at least part of oil of the pilot pump returns to the oil tank through the second unloading oil way, so that the energy waste of the heating oil return tank through the first throttling hole on the first unloading oil way is greatly reduced, and the energy saving performance of the whole hydraulic system is further improved.
Other features of the present invention and advantages thereof will become apparent from the following detailed description of exemplary embodiments thereof, which proceeds with reference to the accompanying drawings.
Drawings
The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the invention and together with the description serve to explain the invention without limiting the invention. In the drawings:
fig. 1 is a schematic structural diagram of a hydraulic system of an excavator according to an embodiment of the present invention;
fig. 2 is a schematic structural view of a hydraulic system of an excavator according to another embodiment of the present invention;
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the invention, its application, or uses. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
The relative arrangement of the components and steps, the numerical expressions and numerical values set forth in these embodiments do not limit the scope of the present invention unless specifically stated otherwise. Meanwhile, it should be understood that the sizes of the respective portions shown in the drawings are not drawn in an actual proportional relationship for the convenience of description. Techniques, methods, and apparatus known to those of ordinary skill in the relevant art may not be discussed in detail, but are intended to be part of the specification where appropriate. In all examples shown and discussed herein, any particular value should be construed as merely illustrative, and not limiting. Thus, other examples of the exemplary embodiments may have different values. It should be noted that: like reference numbers and letters refer to like items in the following figures, and thus, once an item is defined in one figure, further discussion thereof is not required in subsequent figures.
Spatially relative terms, such as "above … …," "above … …," "above … …," "above," and the like, may be used herein for ease of description to describe one device or feature's spatial relationship to another device or feature as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if a device in the figures is turned over, devices described as "above" or "on" other devices or configurations would then be oriented "below" or "under" the other devices or configurations. Thus, the exemplary term "above … …" can include both an orientation of "above … …" and "below … …". The device may be otherwise variously positioned and the spatially relative descriptors used herein interpreted accordingly.
The hydraulic system of the excavator comprises a pilot oil source valve group for supplying oil to the pilot system and a safety handle for controlling a solenoid valve switch in the pilot oil source valve group. The safety handle is a main switch for controlling the action of the whole vehicle, and the safety handle is closed, so that the whole vehicle cannot act; the safety handle is opened, and the whole vehicle can act. When the excavator is maintained, the engine needs to be closed and the safety handle needs to be opened, and at the moment, the valve core is opened by using the pressure of the energy accumulator of the pilot oil source valve group and high-pressure oil is discharged to complete pressure relief.
Referring to fig. 1 and 2, a hydraulic system of an excavator according to an embodiment of the present invention includes:
a power unit 2 including a main pump 21 and a pilot pump 22;
a main valve 5 having a first relief oil passage provided with a first orifice 51;
a pilot valve 4; and
the pilot oil source valve group 3 is provided with an oil inlet P connected with the pilot pump 22, an unloading oil port A connected with a first unloading oil path of the main valve 5, a first oil outlet B1 connected with the pilot valve 4 and an oil outlet T connected with the oil tank 1, the oil inlet P is communicated with the unloading oil port A, the pilot oil source valve group 3 comprises a first control valve 31 arranged between the oil inlet P and the first oil outlet B1 and a second unloading oil path arranged between the oil inlet P and the oil outlet T, and in a first working state, oil in the oil inlet P flows to the first oil outlet B1 through the first control valve 31; in a second working state, at least part of oil in the oil inlet P returns to the oil tank 1 through a second unloading oil way.
When the safety handle is closed after the engine of the excavator is started, the pilot oil source valve group 3 is in the second working state at the moment, and at least part of oil of the pilot pump 22 returns to the oil tank 1 through the second unloading oil way, so that the energy waste of the heating oil return tank through the first throttling hole on the first unloading oil way is greatly reduced, and the energy saving performance of the whole hydraulic system is further improved.
Specifically, in the present embodiment, as shown in fig. 1, the first control valve 31 has a first port C, a second port D, and a third port E, the first port C of the first control valve 31 is connected to the oil inlet P, the second port D of the first control valve 31 is connected to the oil discharge port T, the third port E of the first control valve 31 is connected to the first oil outlet B1, the second unloading oil path is connected to the third port E of the first control valve 31 to be connected to the oil discharge port T through the first control valve 31, and the third port E is selectively communicated with the first port C and the second port D to switch the pilot oil source valve group 3 between the first working state and the second working state. Specifically, when the pilot oil source valve group 3 is in the first working state, the first control valve 31 is in the right position, at this time, the third oil port E is communicated with the first oil port C, and the oil in the oil inlet P flows to the third oil port E through the first oil port C and flows to the first oil outlet B1 to supply oil to the pilot valve 4; when the pilot oil source valve group 3 is in the second working state, the first control valve 31 is in the left position, the first oil port C is closed at this time, the third oil port E is communicated with the second oil port D, the second oil port D is communicated with the oil discharge port T, and at this time, the oil of the oil inlet P flows to the third oil port E through the second unloading oil path and flows to the oil discharge port T through the second oil port D, so that unloading is completed.
As shown in fig. 1, the second unloading oil passage of the present embodiment includes an unloading check valve 34. The unloading check valve 34 is arranged to prevent the oil in the third oil port E from flowing back to the oil inlet P through the second unloading oil path when the pilot oil source valve group 3 is in the first working state.
The second unloading oil passage of the present embodiment further includes a second orifice 35 provided between the unloading check valve 34 and the drain port T, the opening degree of the second orifice being larger than that of the first orifice. Therefore, at least part of the pressure oil of the pilot pump 22 can return to the oil tank through the second unloading oil path, so that the throttling heating oil return tank passing through the inner part of the main valve 5 is greatly reduced, and the energy waste is reduced.
The hydraulic system of the present embodiment includes at least two throttle devices provided with second throttle holes, and the opening degrees of the second throttle holes of the at least two throttle devices are different and are replaceably provided. The throttling device with the corresponding opening degree can be selected according to actual conditions to be replaced and installed on the system, and most of the pressure oil of the pilot pump 22 can return to the oil tank through the loop by installing the throttling device with the second throttling hole 35 with the proper size, so that energy waste is reduced.
Of course, the opening-adjustable second throttle hole may be directly provided.
The hydraulic system of the present embodiment further includes an accumulator 7. The energy accumulator 7 is connected with an oil inlet P of the pilot oil source valve group 3 through an oil inlet one-way valve 37. When the whole machine is depressurized, the safety handle is opened to enable the first control valve 31 to be in the right position, the oil liquid of the energy accumulator 7 flows to the first oil outlet B1 through the first control valve 31 and then enters the pilot valve 4, so that the pilot valve 4 controls the main valve spool to be opened to discharge the high-pressure oil, and the depressurization is completed. The unloading check valve 34 prevents the oil of the accumulator 7 from returning to the oil inlet P through the second unloading oil passage and from being unloaded through the first unloading oil passage inside the main valve 5.
In another embodiment, as shown in FIG. 2, the second relief oil passage includes an on-off valve 36. The on-off valve 36 controls the on-off of the second unloading oil path, and in the first working state, the first control valve 31 is in the right position, and at this time, the oil in the oil inlet P flows to the first oil outlet B1 and flows to the pilot valve 4 through the first control valve 31. The first control end of the on-off valve 36 is connected with the oil inlet F thereof, the second control end is connected with the first oil outlet B1, oil in the oil inlet P flows to the first oil outlet B1 through the oil inlet check valve 37, the oil pressure of the first oil outlet B1 is approximately equal to the oil pressure of the oil inlet P, and the second control end of the on-off valve 36 is further provided with a spring, so that the pressure of the second control end is greater than that of the first control end, the on-off valve 36 is positioned at the right position, and the second unloading oil way is disconnected; in the second working state, the first control valve 31 is in the left position, the first port C is closed, at this time, no pressure oil flows into the first oil outlet B1, the second control end only has a spring, and the first control end is communicated with the oil inlet F thereof, so that the on-off valve 36 is in the left position under the action of the two control ends at this time to communicate the second unloading oil path, and all the oil in the oil inlet P is unloaded through the second unloading oil path, but not through the throttling unloading of the first unloading oil path inside the main valve 5, thereby achieving the energy-saving effect.
In other embodiments not shown in the drawings, the on-off valve can also be an electromagnetic valve, and the on-off of the on-off valve is changed by adjusting the magnitude of the control current according to the working state.
The first control valve 31 of the present embodiment is a solenoid valve and is controlled by a safety handle. When the safety handle is opened, the first control valve 31 is in the right position; when the safety handle is closed, the first control valve is in a left position.
The hydraulic system of the present embodiment further includes a travel motor 6. The main valve 5 has a pressurization control port G. The pilot oil source valve group 3 further has a second oil outlet B2 connected with the pressurization control port G and a third oil outlet B3 connected with the traveling motor 6, and includes a second control valve 32 disposed between the oil inlet P and the second oil outlet B2 and a third control valve 33 disposed between the oil inlet P and the third oil outlet B3.
The second control valve 32 and the third control valve 33 of the present embodiment are both solenoid valves.
The embodiment also provides an excavator, which comprises the hydraulic system provided by each embodiment.
The structure of the hydraulic system according to two embodiments of the present invention will be described in detail with reference to fig. 1 and 2, respectively.
As shown in fig. 1, the hydraulic system of the present embodiment includes an oil tank 1, a power unit 2, a pilot oil source valve group 3, a pilot valve 4, a main valve 5, a travel motor 6, and an accumulator 7.
The power unit 2 includes a main pump 21 and a pilot pump 22. The main valve 5 includes a first orifice 51, a main valve spool 52, and a relief valve 53. The first orifice 51 is located on the first relief oil passage. The control end of the relief valve 53 is connected to the pressurization control port G of the main valve 5. The pilot oil source valve group 3 includes a first control valve 31, a second control valve 32, a third control valve 33, an unloading check valve 34, a second orifice 35, and an oil inlet check valve 37.
The main pump 21 outputs oil to the main valve 5. An oil outlet of the pilot pump 22 is connected with an oil inlet P of the pilot oil source valve group 3 to supply oil to the pilot oil source valve group 3. An oil inlet P of the pilot oil source valve group 3 is communicated with an unloading oil port A, and the unloading oil port A is communicated with a first unloading oil way in the main valve 5. An oil inlet P of the pilot oil source valve group 3 is connected with the energy accumulator 7 and the first control valve 31 through an oil inlet one-way valve 37. The oil inlet P is also connected with a second control valve 32 and a third control valve 33. The oil inlet P is connected to the third port E of the first control valve 31 through the unloading check valve 34 and the second orifice 35.
The first control valve 31, the second control valve 32, and the third control valve 33 of the present embodiment are all solenoid valves and each have two operating positions. The structure will be described in detail below by taking the first control valve 31 as an example. The first control valve 31 has a first port C, a second port D, and a third port E. When the oil is communicated at the left position, the first oil port C is cut off, and the second oil port D is communicated with the third oil port E; when the oil is communicated at the right position, the second oil port D is cut off, and the first oil port C is communicated with the third oil port E. The first port C of the first control valve 31 is connected to the oil inlet P, the second port D is connected to the oil discharge port T, and the third port E is connected to the first oil outlet B1.
The pilot pump 22 outputs hydraulic oil to an oil inlet P of the pilot oil source valve group 3, the pressure oil respectively flows to the energy accumulator 7 and the three control valves, the first oil outlet B1 leads to the pilot valve 4, the second oil outlet B2 leads to a pressurization control port G of the main valve 5, and the third oil outlet B3 leads to a high-low speed control port of the walking motor 6.
In the hydraulic system of the present embodiment, a second unloading oil passage is added to the interior of the pilot oil source valve group 3, and an unloading check valve 34 and a second orifice 35 are added to the second unloading oil passage. When the engine of the excavator is started and the safety handle is closed, the first control valve 31 is powered off, and the oil in the oil inlet P flows to the third oil port E and the second oil port D of the first control valve 31 through the unloading one-way valve 34 and the second throttle hole 35 on the second unloading oil path to complete unloading. By adjusting the size of the second orifice 35, more than 90% of the pressure oil of the pilot pump 22 can pass through the return tank of the circuit, thereby greatly reducing the throttling heating return tank passing through the main valve 5 and avoiding the waste of energy.
When the whole machine is decompressed, the safety handle is opened to enable the first control valve 31 to be positioned at the right position, and because the unloading one-way valve 34 is installed on the second unloading oil path, the pressure oil in the energy accumulator 7 can only flow to the pilot valve 4 through the first oil outlet B1 and can not flow through the throttling oil return tank in the main valve.
As shown in fig. 2, a hydraulic system according to another embodiment is different from the hydraulic system according to the embodiment shown in fig. 1 in that an on-off valve 36 is provided in the second unloading oil passage in the present embodiment. An oil inlet F of the on-off valve 36 is connected with an oil inlet P of the pilot oil source valve group 3, an oil outlet H of the on-off valve 36 is connected with an oil drain port T of the pilot oil source valve group 3, a first control end of the on-off valve 36 is connected with the oil inlet F thereof, a second control end of the on-off valve 36 is connected with a first oil outlet B1, and the oil inlet of the on-off valve 36 and the oil outlet thereof can be arranged in an on-off manner.
In the present embodiment, in the first working state, the first control valve 31 is in the right position, and at this time, the oil in the oil inlet P flows to the first oil outlet B1 and to the pilot valve 4 through the first control valve 31. The first control end of the on-off valve 36 is connected with the oil inlet F thereof, the second control end is connected with the first oil outlet B1, oil in the oil inlet P flows to the first oil outlet B1 through the oil inlet check valve 37, the oil pressure of the first oil outlet B1 is approximately equal to the oil pressure of the oil inlet P, and the second control end of the on-off valve 36 is further provided with a spring, so that the pressure of the second control end is greater than that of the first control end, the on-off valve 36 is positioned at the right position, and the second unloading oil way is disconnected; in the second working state, the first control valve 31 is in the left position, the first port C is closed, at this time, no pressure oil flows into the first oil outlet B1, the second control end only has a spring, and the first control end is communicated with the oil inlet F thereof, so that the on-off valve 36 is in the left position under the action of the two control ends at this time to communicate the second unloading oil path, and all the oil in the oil inlet P is unloaded through the second unloading oil path, but not through the throttling unloading of the first unloading oil path inside the main valve 5, thereby achieving the energy-saving effect.
Other structures and functions not described in this embodiment can be described with reference to the embodiment shown in fig. 1, and are not described again here.
As can be seen from the above, in the hydraulic system according to the embodiment of the present invention, the second unloading oil passage is added in the pilot oil source valve group 3, so that when the pilot handle is closed after the engine is started, at least part of the pressure oil of the pilot pump 22 is unloaded through the second unloading oil passage, which saves energy compared with the case where all the pressure oil is unloaded through the first unloading oil passage in the main valve 5.
Finally, it should be noted that: the above examples are only intended to illustrate the technical solution of the present invention and not to limit it; although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art will understand that: modifications to the specific embodiments of the invention or equivalent substitutions for parts of the technical features may be made; without departing from the spirit of the present invention, it is intended to cover all aspects of the invention as defined by the appended claims.
Claims (11)
1. A hydraulic system of an excavator, comprising:
a power unit (2) including a main pump (21) and a pilot pump (22);
a main valve (5) having a first relief oil passage provided with a first orifice (51);
a pilot valve (4); and
the pilot oil source valve group (3) is provided with an oil inlet (P) connected with the pilot pump (22), an unloading oil port (A) connected with a first unloading oil path of the main valve (5), a first oil outlet (B1) connected with the pilot valve (4) and an oil outlet (T) connected with the oil tank (1), the oil inlet (P) is communicated with the unloading oil port (A), the pilot oil source valve group (3) comprises a first control valve (31) arranged between the oil inlet (P) and the first oil outlet (B1) and a second unloading oil path arranged between the oil inlet (P) and the oil outlet (T), and in a first working state, oil in the oil inlet (P) flows to the first oil outlet (B1) through the first control valve (31); in a second working state, at least part of oil in the oil inlet (P) returns to the oil tank (1) through the second unloading oil way.
2. The hydraulic system of the excavator according to claim 1, wherein the first control valve (31) has a first port (C), a second port (D) and a third port (E), a first oil port (C) of the first control valve (31) is connected with the oil inlet (P), the second oil port (D) of the first control valve (31) is connected with the oil discharge port (T), the third oil port (E) of the first control valve (31) is connected with the first oil outlet (B1), the second unloading oil path is connected with the oil discharge port (T) through the first control valve (31), the third oil port (E) is selectively communicated with the first oil port (C) and the second oil port (D) to switch the pilot oil source valve group (3) between the first working state and the second working state.
3. The hydraulic system of the excavator according to claim 2, further comprising an accumulator (7), wherein the accumulator (7) is connected with the first oil port of the first control valve (31) and is connected with the oil inlet (P) of the pilot oil source valve group (3) through an oil inlet check valve (37).
4. The hydraulic system of the excavator according to claim 1, wherein the second unloading oil passage includes an unloading check valve (34).
5. The hydraulic system of the excavator according to claim 4, wherein the second unloading oil path further includes a second orifice (35) provided between the unloading check valve (34) and the oil drain port (T), a first end of the second orifice (35) is connected to the unloading check valve (34), a second end of the second orifice (35) is connected to the first oil outlet (B1) and to the oil drain port (T) through the first control valve (31), and an opening degree of the second orifice (35) is larger than an opening degree of the first orifice (51).
6. The hydraulic system of the excavator according to claim 5, wherein the opening degree of the second throttle hole (35) is adjustably set; or the hydraulic system comprises at least two throttling devices provided with second throttling holes (35), and the opening degrees of the second throttling holes (35) of the at least two throttling devices are different and are arranged in an exchangeable mode.
7. The hydraulic system of the excavator according to claim 1, wherein the second unloading oil path comprises an on-off valve (36), an oil inlet (F) of the on-off valve (36) is connected with an oil inlet (P) of the pilot oil source valve group (3), an oil outlet (H) of the on-off valve (36) is connected with the oil drain port (T), and an oil inlet and an oil outlet of the on-off valve (36) are arranged in an on-off manner.
8. The hydraulic system of the excavator according to claim 7, wherein a first control end of the on-off valve (36) is connected with an oil inlet (F) thereof, a second control end of the on-off valve (36) is connected with the first oil outlet (B1) and is provided with a spring, and the on-off of the on-off valve (36) is controlled by the oil pressure of the first control end of the on-off valve (36) and the oil pressure of the second control end of the on-off valve (36).
9. The hydraulic system of an excavator according to claim 1, wherein the first control valve (31) is a solenoid valve and is controlled by a safety handle.
10. The hydraulic system of an excavator according to claim 1, further comprising a walking motor (6), said main valve (5) having a pressure-increasing control port (G), said pilot oil source valve group (3) further having a second oil outlet (B2) connected with said pressure-increasing control port (G) and a third oil outlet (B3) connected with said walking motor (6) and comprising a second control valve (32) disposed between said oil inlet (P) and said second oil outlet (B2) and a third control valve (33) disposed between said oil inlet (P) and said third oil outlet (B3).
11. An excavator comprising a hydraulic system as claimed in any one of claims 1 to 10.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010611285.8A CN111691492B (en) | 2020-06-30 | 2020-06-30 | Hydraulic system of excavator and excavator |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010611285.8A CN111691492B (en) | 2020-06-30 | 2020-06-30 | Hydraulic system of excavator and excavator |
Publications (2)
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113819095A (en) * | 2021-08-16 | 2021-12-21 | 中联重科土方机械有限公司 | Hydraulic system, control method of hydraulic system, and engineering machine |
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| CN113819095A (en) * | 2021-08-16 | 2021-12-21 | 中联重科土方机械有限公司 | Hydraulic system, control method of hydraulic system, and engineering machine |
| CN113819095B (en) * | 2021-08-16 | 2023-12-08 | 中联重科土方机械有限公司 | Hydraulic system, control method of hydraulic system and engineering machinery |
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| CN111691492B (en) | 2022-06-28 |
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