阅读说明：本技术 挖掘机的液压系统和挖掘机 (Hydraulic system of excavator and excavator ) 是由 尹超 黄喆 董步军 孙忠永 崔广伟 孙本强 刘贺 张升霞 张云威 曾川 张俊 于 2021-08-05 设计创作，主要内容包括：本发明公开一种挖掘机的液压系统和挖掘机。挖掘机的液压系统包括主泵、先导泵、单向机具、双向机具、第一换向阀、切换阀和先导阀组。切换阀动作以控制第二控制油口与第一换向阀的第四油口连通或与油箱连通。先导阀组包括第一梭阀、单联控制阀、双联控制阀、第一电比例减压阀和第二电比例减压阀,第一梭阀的出油口与第一换向阀的第一液控端连接,第一梭阀的第一进油口与单联控制阀连接,第二进油口与双联控制阀的第一先导油口连接,第一换向阀的第二液控端与双联控制阀的第二先导油口连接,第一电比例减压阀与单联控制阀和切换阀的液控端连接,第二电比例减压阀与双联控制阀连接,先导泵的出油口选择地与第一电比例减压阀或第二电比例减压阀连通。(The invention discloses a hydraulic system of an excavator and the excavator. The hydraulic system of the excavator comprises a main pump, a pilot pump, a one-way machine tool, a two-way machine tool, a first reversing valve, a switching valve and a pilot valve group. The switching valve acts to control the second control oil port to be communicated with the fourth oil port of the first reversing valve or the oil tank. The pilot valve group comprises a first shuttle valve, a single-connection control valve, a double-connection control valve, a first electric proportional pressure reducing valve and a second electric proportional pressure reducing valve, wherein an oil outlet of the first shuttle valve is connected with a first pilot oil port of a first reversing valve, a first oil inlet of the first shuttle valve is connected with the single-connection control valve, a second oil inlet of the second shuttle valve is connected with a first pilot oil port of the double-connection control valve, a second pilot oil port of the first reversing valve is connected with a second pilot oil port of the double-connection control valve, the first electric proportional pressure reducing valve is connected with the single-connection control valve and a pilot oil port of a switching valve, the second electric proportional pressure reducing valve is connected with the double-connection control valve, and an oil outlet of a pilot pump is selectively communicated with the first electric proportional pressure reducing valve or the second electric proportional pressure reducing valve.)

1. A hydraulic system of an excavator, comprising:

a main pump (20);

a pilot pump (30);

the one-way machine tool (4) comprises an oil supply port and an oil return port;

a bi-directional implement (5) including a first implement oil port and a second implement oil port; and

the control valve group is provided with a first control oil port and a second control oil port, when the one-way machine works, the first control oil port is communicated with an oil supply port of the one-way machine (4), and the second control oil port is communicated with an oil return port of the one-way machine (4); when the two-way machine works, the first control oil port is communicated with a first machine oil port of the two-way machine, the second control oil port is communicated with a second machine oil port of the two-way machine (5), the control valve group comprises a first reversing valve (2), a switching valve (9) and a pilot valve group,

the first reversing valve (2) is provided with a first oil port, a second oil port, a third oil port and a fourth oil port, the first oil port of the first reversing valve (2) is connected with the main pump (20), the second oil port is connected with an oil tank, the third oil port is connected with the first control oil port, the fourth oil port is connected with the second control oil port through the switching valve (9), and the first reversing valve (2) is provided with a first hydraulic control end and a second hydraulic control end;

the switching valve (9) performs transposition action to control the second control oil port to be communicated with the fourth oil port of the first reversing valve (2) or communicated with an oil tank;

the pilot valve group comprises a first shuttle valve (8), a single-connection control valve (6), a double-connection control valve (1), a first electric proportional pressure reducing valve (15) and a second electric proportional pressure reducing valve (16), an oil outlet of the first shuttle valve (8) is connected with a first hydraulic control end of a first reversing valve (2), a first oil inlet of the first shuttle valve (8) is connected with the single-connection control valve (6), a second oil inlet of the first shuttle valve (8) is connected with a first pilot oil port (A1) of the double-connection control valve (1), a second hydraulic control end of the first reversing valve (2) is connected with a second pilot oil port (A2) of the double-connection control valve (1), the first electric proportional pressure reducing valve (15) is connected with the single-connection control valve (6) and a hydraulic control end of a switching valve (9), and the second electric proportional pressure reducing valve (16) is connected with the double-connection control valve (1), the oil outlet of the pilot pump (30) is selectively communicated with the first electric proportional pressure reducing valve (15) or the second electric proportional pressure reducing valve (16).

2. The hydraulic system of the excavator according to claim 1, wherein the pilot valve group further comprises a second direction valve (13), the second direction valve (13) is connected with the pilot pump (30) and the first electro-proportional pressure reducing valve (15) and the second electro-proportional pressure reducing valve (16) and used for controlling oil supply to the first electro-proportional pressure reducing valve (15) or the second electro-proportional pressure reducing valve (16), when the second direction valve (13) is in a first working position, an oil outlet of the pilot pump (30) is communicated with the first electro-proportional pressure reducing valve (15), and when the second direction valve (13) is in a second working position, an oil outlet of the pilot pump (30) is communicated with the second electro-proportional pressure reducing valve (16).

3. The hydraulic system of an excavator according to claim 1, further comprising a rotary implement (11), a third directional control valve (10) and a brake control assembly (12), wherein the rotary implement (11) comprises a first working oil port and a second working oil port and comprises a brake shaft (111), the third directional control valve (10) is disposed between the main pump (20) and the rotary implement (11) for controlling the oil of the main pump (20) to flow to the first working oil port or the second working oil port of the rotary implement (11), the brake control assembly (12) comprises a brake cylinder (122) and a brake directional control valve (123), a spring is disposed in a rodless cavity of the brake cylinder (122), the first oil port of the brake directional control valve (123) is connected with the pilot pump (30), and the second oil port of the brake directional control valve (123) is connected with an oil tank, a third oil port of the brake reversing valve is connected with a rod cavity of the brake oil cylinder (122), the brake reversing valve (123) is provided with a first working position and a second working position, and in the first working position, the first oil port is communicated with the third oil port to supply oil to the rod cavity of the brake oil cylinder; and in a second working position, the second oil port is communicated with the third oil port so that the oil in the rod cavity of the brake oil cylinder flows to an oil tank.

4. The hydraulic system of the excavator according to claim 3, wherein the pilot valve group further comprises a second shuttle valve (14), an oil outlet of the second shuttle valve (14) is connected with a first oil port of the brake reversing valve, a first oil inlet of the second shuttle valve (14) is connected with a first electric proportional pressure reducing valve (15), and a second oil inlet of the second shuttle valve (14) is connected with a second electric proportional pressure reducing valve (16).

5. The hydraulic system of the excavator according to claim 3, wherein the brake directional control valve (123) has a hydraulic control end, the pilot valve set further comprises an electric proportional pressure reducing valve set (7), an oil inlet of the electric proportional pressure reducing valve set (7) is connected with the pilot pump (30), a first oil outlet (B1) of the electric proportional pressure reducing valve set (7) is connected with the hydraulic control end of the brake directional control valve, a second oil outlet (B2) of the electric proportional pressure reducing valve set (7) is connected with one hydraulic control end of a third directional control valve (10), and a third oil outlet (B3) of the electric proportional pressure reducing valve set (7) is connected with the other hydraulic control end of the third directional control valve (10).

6. The hydraulic system of the excavator of claim 3, wherein the brake control assembly further comprises a flow control valve (124), and the second port of the brake directional valve (123) is connected with a tank through the flow control valve (124).

7. The hydraulic system of the excavator of claim 6 wherein the brake control assembly further includes a throttling element disposed between the second port of the brake directional valve and the flow control valve (124).

8. An excavator, characterized by comprising the hydraulic system of the excavator according to any one of claims 1 to 7.

Technical Field

The invention relates to the field of engineering machinery, in particular to a hydraulic system of an excavator and the excavator.

Background

Excavators are typically equipped with multiple implements, including one-way implements, two-way implements, swing implements, and the like. Specifically, such as a breaking hammer, a hydraulic shear, etc. Aiming at the multiple machines, the hydraulic system of the excavator needs to set different hydraulic control pipelines aiming at different machines, each hydraulic control pipeline cannot be used for controlling a one-way machine and a two-way machine, and the pressure and the flow of the one-way machine and the two-way machine can be controlled according to the requirement, so that the structure of the hydraulic system is complex, and the control is more complex. Meanwhile, when the machine tool does not need to be operated, the misoperation preventing function is not arranged on the machine tool control button, and the safety of the hydraulic system is low.

It is important to note here that the statements in this background section merely provide background information related to the present disclosure and may not necessarily constitute prior art.

Disclosure of Invention

The invention provides a hydraulic system of an excavator and the excavator, which are used for matching and controlling multiple machines and tools at the same time.

A first aspect of the present invention provides a hydraulic system of an excavator, including:

a main pump;

a pilot pump;

the one-way machine comprises an oil supply port and an oil return port;

a bi-directional implement including a first implement oil port and a second implement oil port; and

the control valve group is provided with a first control oil port and a second control oil port, when the one-way machine works, the first control oil port is communicated with an oil supply port of the one-way machine, and the second control oil port is communicated with an oil return port of the one-way machine; when the two-way machine tool works, the first control oil port is communicated with the first machine tool oil port of the two-way machine tool, the second control oil port is communicated with the second machine tool oil port of the two-way machine tool, the control valve group comprises a first reversing valve, a switching valve and a pilot valve group,

the first reversing valve is provided with a first oil port, a second oil port, a third oil port and a fourth oil port, the first oil port of the first reversing valve is connected with the main pump, the second oil port is connected with the oil tank, the third oil port is connected with the first control oil port, the fourth oil port is connected with the second control oil port through the switching valve, and the first reversing valve is provided with a first hydraulic control end and a second hydraulic control end;

the switching valve performs transposition action to control the second control oil port to be communicated with the fourth oil port of the first reversing valve or the oil tank;

the pilot valve group comprises a first shuttle valve, a single-connection control valve, a double-connection control valve, a first electric proportional pressure reducing valve and a second electric proportional pressure reducing valve, an oil outlet of the first shuttle valve is connected with a first pilot oil port of a first reversing valve, a first oil inlet of the first shuttle valve is connected with the single-connection control valve, a second oil inlet of the first shuttle valve is connected with a first pilot oil port of the double-connection control valve, a second pilot oil port of the first reversing valve is connected with a second pilot oil port of the double-connection control valve, the first electric proportional pressure reducing valve is connected with ends of the single-connection control valve and a switching valve, the second electric proportional pressure reducing valve is connected with the double-connection control valve, and an oil outlet of a pilot pump is selectively communicated with the first electric proportional pressure reducing valve or the second electric proportional pressure reducing valve.

In some embodiments, the pilot valve group further includes a second reversing valve, the second reversing valve is connected with the pilot pump and the first electric proportional pressure reducing valve and the second electric proportional pressure reducing valve and is used for controlling the first electric proportional pressure reducing valve or the second electric proportional pressure reducing valve to supply oil, when the second reversing valve is in the first working position, the oil outlet of the pilot pump is communicated with the first electric proportional pressure reducing valve, and when the second reversing valve is in the second working position, the oil outlet of the pilot pump is communicated with the second electric proportional pressure reducing valve.

In some embodiments, the hydraulic system further includes a rotary machine tool, a third directional valve and a brake control assembly, the rotary machine tool includes a first working oil port and a second working oil port and includes a brake shaft, the third directional valve is disposed between the main pump and the rotary machine tool for controlling oil of the main pump to flow to the first working oil port or the second working oil port of the rotary machine tool, the brake control assembly includes a brake cylinder and a brake directional valve, a spring is disposed in a rodless cavity of the brake cylinder, a first oil port of the brake directional valve is connected with the pilot pump, a second oil port of the brake directional valve is connected with an oil tank, a third oil port of the brake directional valve is connected with a rod cavity of the brake cylinder, the brake directional valve has a first working position and a second working position, and in the first working position, the first oil port is communicated with the third oil port to supply oil to the rod cavity of the brake cylinder; and in the second working position, the second oil port is communicated with the third oil port so that the oil in the rod cavity of the brake oil cylinder flows to the oil tank.

In some embodiments, the pilot valve group further includes a second shuttle valve, an oil outlet of the second shuttle valve is connected to the first oil port of the brake reversing valve, a first oil inlet of the second shuttle valve is connected to the first electro-proportional pressure reducing valve, and a second oil inlet of the second shuttle valve is connected to the second electro-proportional pressure reducing valve.

In some embodiments, the brake reversing valve has a hydraulic control end, the pilot valve group further includes an electric proportional pressure reducing valve group, an oil inlet of the electric proportional pressure reducing valve group is connected with the pilot pump, a first oil outlet of the electric proportional pressure reducing valve group is connected with the hydraulic control end of the brake reversing valve, a second oil outlet of the electric proportional pressure reducing valve group is connected with one hydraulic control end of the third reversing valve, and a third oil outlet of the electric proportional pressure reducing valve group is connected with the other hydraulic control end of the third reversing valve.

In some embodiments, the brake control assembly further comprises a flow control valve, and the second oil port of the brake directional valve is connected with the oil tank through the flow control valve.

In some embodiments, the brake control assembly further comprises a throttling element disposed between the second oil port of the brake directional valve and the flow control valve.

The invention provides an excavator, which comprises the hydraulic system of the excavator.

Based on the aspects provided by the invention, the hydraulic system of the excavator comprises a main pump, a pilot pump, a one-way implement, a two-way implement and a control valve group. The control valve group is provided with a first control oil port and a second control oil port, when the one-way machine works, the first control oil port is communicated with an oil supply port of the one-way machine, and the second control oil port is communicated with an oil return port of the one-way machine; when the two-way machine works, the first control oil port is communicated with the first machine oil port of the two-way machine, the second control oil port is communicated with the second machine oil port of the two-way machine, and the control valve group comprises a first reversing valve, a switching valve and a pilot valve group. The first oil port of the first reversing valve is connected with the main pump, the second oil port is connected with the oil tank, the third oil port is connected with the first control oil port, and the fourth oil port is connected with the second control oil port through the switching valve. The first directional control valve has a first pilot operated end and a second pilot operated end. And the switching valve acts to control the second control oil port to be communicated with the fourth oil port of the first reversing valve or the oil tank. The pilot valve group comprises a first shuttle valve, a single-connection control valve, a double-connection control valve, a first electric proportional pressure reducing valve and a second electric proportional pressure reducing valve, an oil outlet of the first shuttle valve is connected with a first pilot oil port of a first reversing valve, a first oil inlet of the first shuttle valve is connected with the single-connection control valve, a second oil inlet of the first shuttle valve is connected with a first pilot oil port of the double-connection control valve, a second pilot oil port of the first reversing valve is connected with a second pilot oil port of the double-connection control valve, the first electric proportional pressure reducing valve is connected with ends of the single-connection control valve and a switching valve, the second electric proportional pressure reducing valve is connected with the double-connection control valve, and an oil outlet of a pilot pump is selectively communicated with the first electric proportional pressure reducing valve or the second electric proportional pressure reducing valve. The hydraulic system of the excavator can control a one-way machine tool and a two-way machine tool by adopting the same set of control oil way. And this hydraulic system realizes the control to the fuel feeding of the pilot oil of single gang control valve and cuts off through setting up first electric proportional pressure reducing valve, and then prevents the single gang control valve maloperation. And the first electric proportional pressure reducing valve can carry out proportional control on the pilot oil output by the single-connection control valve, so that the valve core displacement of the first reversing valve is controlled, and the flow control of a one-way machine is realized. The first electric proportional pressure reducing valve can also control the action of the switching valve, so that the work switching of the one-way machine tool and the two-way machine tool is realized. Similarly, the second electric proportional pressure reducing valve is arranged to realize the control of oil supply and cut-off of pilot oil of the duplex control valve, so that misoperation of the duplex control valve is prevented. And the second electric proportional pressure reducing valve can carry out proportional control on pilot oil output by the duplex control valve, so that the valve core displacement of the first reversing valve is controlled, and the flow control of a two-way machine is realized.

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.

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.

Referring to fig. 1, in some embodiments, a hydraulic system of an excavator includes a main pump 20, a pilot pump 30, a one-way implement 4, a two-way implement 5, and a control valve set. The one-way tool 4 includes an oil supply port and an oil return port. The bi-directional implement 5 includes a first implement oil port and a second implement oil port. The control valve group is provided with a first control oil port M and a second control oil port N, when the one-way machine 4 works, the first control oil port M is communicated with an oil supply port of the one-way machine 4, and the second control oil port N is communicated with an oil return port of the one-way machine 4; when the two-way machine 5 works, the first control oil port M is communicated with the first machine oil port of the two-way machine 5, the second control oil port N is communicated with the second machine oil port of the two-way machine 5, and the control valve group comprises a first reversing valve 2, a switching valve 9 and a pilot valve group.

The first reversing valve 2 is provided with a first oil port, a second oil port, a third oil port and a fourth oil port, the first oil port of the first reversing valve 2 is connected with the main pump 20, the second oil port is connected with the oil tank, the third oil port is connected with the first control oil port M, and the fourth oil port is connected with the second control oil port N through the switching valve 9. The first directional control valve 2 has a first pilot control end and a second pilot control end. The switching valve 9 acts to control the second control oil port N to be communicated with the fourth oil port of the first directional valve 2 or communicated with the oil tank. The pilot valve group comprises a first shuttle valve 8, a single-connection control valve 6, a double-connection control valve 1, a first electric proportional pressure reducing valve 15 and a second electric proportional pressure reducing valve 16, an oil outlet of the first shuttle valve 8 is connected with a first pilot oil port A1 of the first reversing valve 2, a first oil inlet of the first shuttle valve 8 is connected with the single-connection control valve 6, a second oil inlet of the first shuttle valve 8 is connected with a first pilot oil port A1 of the double-connection control valve 1, a second hydraulic control port of the first reversing valve 2 is connected with a second pilot oil port A2 of the double-connection control valve 1, the first electric proportional pressure reducing valve 15 is connected with the single-connection control valve 6 and a pilot oil port of the switching valve 9, the second electric proportional pressure reducing valve 16 is connected with the double-connection control valve 1, and an oil outlet of the pilot pump 30 is selectively communicated with the first electric proportional pressure reducing valve 15 or the second electric proportional pressure reducing valve 16.

The one-way tool 4 and the two-way tool 5 can be selectively assembled on the excavator, when the one-way tool 4 works, and the oil outlet of the pilot pump 30 is communicated with the first electric proportional pressure reducing valve 15, the pilot oil of the pilot pump 30 flows to the first hydraulic control end of the first reversing valve 2 through the first electric proportional pressure reducing valve 15, the single-connection control valve 6 and the first shuttle valve 8, so that the first reversing valve 2 is in a left position, and the main pump 20 supplies oil to the oil supply port of the one-way tool 4; meanwhile, the pilot oil of the pilot pump 30 flows to the pilot control end of the switching valve 9 through the first electro-proportional pressure reducing valve 15, so that the switching valve 9 is in the right position, and the oil return port of the one-way tool 4 returns to the oil tank through the switching valve 9. When the two-way tool 5 works, when the oil outlet of the pilot pump 30 is communicated with the second electric proportional pressure reducing valve 16, the pilot oil of the pilot pump 30 flows to the second pilot control end of the first reversing valve 2 through the second electric proportional pressure reducing valve 16 and the second pilot oil port a2 of the dual control valve 1, so that the first reversing valve 2 is in the right position, meanwhile, because the pilot pump 30 does not supply oil to the first electric proportional pressure reducing valve 15, the switching valve 9 returns to the left position, the oil liquid of the main pump 20 supplies oil to the second tool oil port of the two-way tool 5 through the fourth oil port of the first reversing valve 2, and the oil liquid of the first tool oil port of the two-way tool 5 returns to the oil tank through the first reversing valve 2. Therefore, the hydraulic system of the excavator can control both the one-way machine and the two-way machine by adopting the same set of control oil way. And the hydraulic system realizes the control of oil supply and cut-off of the pilot oil of the single-connection control valve 6 by arranging the first electric proportional pressure reducing valve 15, thereby preventing the single-connection control valve 6 from misoperation. And the first electric proportional pressure reducing valve 15 can carry out proportional control on the pilot oil output by the single-connection control valve 6, so that the valve core displacement of the first reversing valve 2 is controlled, and the flow control of the one-way machine 4 is realized. The first electro-proportional pressure reducing valve 15 can also control the action of the switching valve 9, so that the work switching of the one-way machine tool and the two-way machine tool is realized. Similarly, the second electro-proportional pressure reducing valve 16 is provided to control the supply and cut-off of the pilot oil to the dual control valve 1, thereby preventing the dual control valve from malfunctioning. And the second electric proportional pressure reducing valve can carry out proportional control on pilot oil output by the duplex control valve, so that the valve core displacement of the first reversing valve is controlled, and the flow control of a two-way machine is realized.

The first shuttle valve 8 is arranged so that pilot control oil paths for controlling the one-way machine and the two-way machine do not interfere with each other.

Specifically, in some embodiments, the dual control valve 1 includes two electro-proportional pressure reducing valves, which are respectively used for supplying oil to the first pilot port a1 and the second pilot port a2, and controlling the valve core of the first directional valve 2 to be reversed. The valve core displacement of the first reversing valve 2 is controlled by providing different current values for the duplex control valve 1, so that the flow control of a one-way machine and a two-way machine is realized.

Referring to fig. 1, in some embodiments, the hydraulic system further includes a first electromagnetic spill valve 31 and a second electromagnetic spill valve 32. The first electromagnetic overflow valve 31 is arranged between the third oil port of the first reversing valve 2 and the oil tank, and the second electromagnetic overflow valve 32 is arranged between the fourth oil port of the first reversing valve 2 and the oil tank. The first electromagnetic overflow valve 31 and the second electromagnetic overflow valve 32 are arranged to control the overflow pressure of the first directional valve 2, and further to control the pressure of the one-way tool 4 and the two-way tool 5.

In some embodiments, the pilot valve group further comprises a second direction valve 13. The second reversing valve 13 is connected with the pilot pump 30, the first electric proportional pressure reducing valve 15 and the second electric proportional pressure reducing valve 16 and used for controlling oil supply for the first electric proportional pressure reducing valve 15 or the second electric proportional pressure reducing valve 16, when the second reversing valve 13 is located at a first working position, an oil outlet of the pilot pump 30 is communicated with the first electric proportional pressure reducing valve 15, and when the second reversing valve 13 is located at a second working position, an oil outlet of the pilot pump 30 is communicated with the second electric proportional pressure reducing valve 16.

Specifically, as shown in fig. 1, a first oil port of the second directional valve 13 is connected to an oil tank, a second oil port is connected to the pilot pump 30, a third oil port is connected to the second electro-proportional pressure reducing valve 16, and a fourth oil port is connected to the first electro-proportional pressure reducing valve 15. When the second reversing valve 13 is in the left position, the first oil port is communicated with the third oil port, and the second oil port is communicated with the fourth oil port, so that oil supply to the first electro proportional pressure reducing valve 15 is realized. When the second reversing valve 13 is in the right position, the first oil port is communicated with the fourth oil port, and the second oil port is communicated with the third oil port, so that oil supply to the second electro-proportional pressure reducing valve 16 is realized. It can be known that the working position switching of the second direction valve 13 can control the communication between the pilot pump 30 and one of the first electro-proportional pressure reducing valve 15 and the second electro-proportional pressure reducing valve 16, so as to realize the switching of the pilot pipeline when the one-way implement works or when the two-way implement works.

Referring to fig. 1, in one specific embodiment, the hydraulic system further includes a direction change valve 18 disposed between the pilot pump 30 and the second port of the second direction change valve 13, and a relief valve disposed between the pilot pump 30 and the tank. The reversing valve 18 is directly connected with the pilot pump 30, and can control the on-off of pilot oil of all machines. When the direction change valve 18 is in the lower position, the pilot oil of the pilot pump 30 cannot flow out, and thus the misoperation of all the machines can be prevented.

In some embodiments, the hydraulic system further includes a rotary implement 11, a third directional valve 10, and a brake control assembly 12. The rotary machine tool 11 includes a first working oil port and a second working oil port and includes a brake shaft 111, and the third directional control valve 10 is disposed between the main pump 20 and the rotary machine tool 11 to control the oil of the main pump 20 to flow to the first working oil port or the second working oil port of the rotary machine tool 11. The brake control assembly 12 comprises a brake oil cylinder 122 and a brake reversing valve 123, a spring is arranged in a rodless cavity of the brake oil cylinder 122, a first oil port of the brake reversing valve 123 is connected with the pilot pump 30, a second oil port of the brake reversing valve 123 is connected with an oil tank, a third oil port of the brake reversing valve is connected with a rod cavity of the brake oil cylinder 122, the brake reversing valve 123 has a first working position and a second working position, and in the first working position, the first oil port is communicated with the third oil port to supply oil to the rod cavity of the brake oil cylinder; and in the second working position, the second oil port is communicated with the third oil port so that the oil in the rod cavity of the brake oil cylinder flows to the oil tank.

Specifically, a brake pad is disposed on a piston rod of the brake cylinder 122, and when oil enters a rod chamber of the brake cylinder 122, the piston rod moves to one side of the rodless chamber under the action of oil pressure, so that the brake pad leaves the brake shaft 111 to release braking. When the oil in the rod chamber of the brake cylinder 122 is discharged, the piston rod moves toward the brake shaft 111 under the action of the spring to brake. The brake direction valve 123 operates to control the operation of the brake cylinder 122. Referring to fig. 1, the brake direction valve 123 has a pilot side, and when oil is supplied to the pilot side, the brake direction valve 123 is in an upper position, and pilot oil flows to a rod chamber of the brake cylinder through the brake direction valve 123. When the hydraulic control end drains oil, the brake reversing valve 123 is in the lower position, and oil in the rod cavity of the brake oil cylinder returns to the oil tank through the brake reversing valve 123.

In order to control the pilot control end of the brake directional valve 123, referring to fig. 1, the pilot valve group further includes an electric proportional pressure reducing valve group 7. An oil inlet of the electric proportional pressure reducing valve group 7 is connected with the pilot pump 30, a first oil outlet B1 of the electric proportional pressure reducing valve group 7 is connected with a hydraulic control end of the brake reversing valve 123, a second oil outlet B2 of the electric proportional pressure reducing valve group 7 is connected with one hydraulic control end of the third reversing valve 10, and a third oil outlet B3 of the electric proportional pressure reducing valve group 7 is connected with the other hydraulic control end of the third reversing valve 10.

The electrically proportional pressure reducing valve group 7 includes a first pilot electrically proportional pressure reducing valve 71, a second pilot electrically proportional pressure reducing valve 72, and a third pilot electrically proportional pressure reducing valve 73. The valve core displacement of the brake change valve 123 can be controlled by controlling the current of the first pilot electric proportional pressure reducing valve 71, so that the time control of the stop delay of the slewing machine 11 is realized. When the oil supply to the rotary machine 11 is stopped, the brake control unit 12 is operated, and the hydraulic oil in the rod chamber of the brake cylinder 122 flows back to the oil tank through the brake directional valve 123. Then, the brake shaft 111 stops rotating by the brake cylinder 122, and the swing machine 11 stops completely. The valve core displacement of the brake reversing valve 123 is further controlled by controlling the current value of the first pilot electric proportional pressure reducing valve 71, so that the time control of the stopping delay of the rotary machine tool is realized.

The current of the electric proportional pressure reducing valve group 7 is controlled to control the valve core displacement of the third reversing valve 10, so that the flow of the rotary machine 11 is controlled, and when the rotary machine 11 is not used, the second pilot electric proportional pressure reducing valve 72 and the third pilot electric proportional pressure reducing valve 73 of the electric proportional pressure reducing valve group 7 are not electrified, so that misoperation can be realized.

Specifically, in one embodiment, referring to fig. 1, a first oil port of the third directional valve 10 is connected to the main pump 20 through a check valve, a second oil port of the third directional valve 10 is connected to the oil tank, a third oil port of the third directional valve 10 is connected to a first working oil port of the rotary machine 11, and a fourth oil port of the third directional valve 10 is connected to a second working oil port of the rotary machine 11. The third direction valve 10 operates to control the forward and reverse rotation of the rotary machine 11. When the third directional valve 10 is in the left position, the oil of the main pump 20 flows to a first working oil port of the rotary machine tool, and when the third directional valve 10 is in the right position, the oil of the main pump 20 flows to a second working oil port of the rotary machine tool.

In order to control the working pressure of the rotary machine 11, as shown in fig. 1, the hydraulic system further includes a third overflow valve 171 disposed between the third port of the third direction valve 10 and the oil tank, and a fourth overflow valve 172 disposed between the fourth port of the third direction valve 10 and the oil tank.

Specifically, the third relief valve 171 and the fourth relief valve 172 are electrically proportional relief valves.

The current values between the duplex control valve 1 and the second pilot electric proportional pressure reducing valve 72 and the third pilot electric proportional pressure reducing valve 73 are reasonably adjusted, so that the distribution control of the flow among a plurality of machines is realized under different rotating speeds of the excavator, and the operation coordination among the machines is kept unchanged under different rotating speeds.

In some embodiments, the pilot valve group further includes a second shuttle valve 14, an oil outlet of the second shuttle valve 14 is connected to the first oil port of the brake reversing valve 123, a first oil inlet of the second shuttle valve 14 is connected to the first electro-proportional pressure reducing valve 15, and a second oil inlet of the second shuttle valve 14 is connected to the second electro-proportional pressure reducing valve 16. The second shuttle valve 14 is provided such that whether the pilot pump 30 supplies the first electro-proportional pressure reducing valve 15 or the second electro-proportional pressure reducing valve 16 with oil, one way of oil is supplied to the brake direction changing valve 123 through the second shuttle valve 14, that is, the brake direction changing valve 123 is always supplied with pilot oil. Once the first pilot electric proportional pressure reducing valve 71 is electrified, the hydraulic oil of the second shuttle valve 14 enters the brake cylinder 122 through the brake reversing valve 123, so that the brake pad and the brake shaft 111 are in a separated state, and the rotary machine realizes the function of releasing the brake.

In some embodiments, the brake control assembly further includes a flow control valve 124. The second port of the brake directional valve 123 is connected to the tank through the flow control valve 124.

In some embodiments, the brake control assembly further includes a throttling element disposed between the second port of the brake directional valve and the flow control valve 124. The throttling element is used in combination with the flow control valve 124, and functions as a governor valve to control the flow rate of hydraulic oil and thus the swing delay time of the swing machine 11. When the hydraulic oil flow rate control device and the brake reversing valve 123 act together, the rotation delay time can be further controlled, and the flow rate of the hydraulic oil is stable.

The embodiment of the invention also provides an excavator, which comprises the hydraulic system of the excavator.

In summary, the hydraulic system of the excavator according to the embodiment of the present invention has at least the following advantages:

the hydraulic system of the excavator can be matched with various machines with different pressure and flow requirements at the same time. The hydraulic pipeline of the hydraulic system can be matched with a one-way machine tool and a two-way machine tool, and meanwhile, the pressure and flow of each set of pipeline can be adjusted by adopting an electric proportional control mode. The reversing of the reversing valve is also controlled by an electric control switch, and the reversing valve has the function of preventing misoperation. The rotary machine has the function of stopping time delay, the time delay of the rotary stop is set automatically according to the operation habits of customers, the hydraulic impact during the stop is reduced, and the service life of the machine is prolonged.

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.