Hydraulic system and control method for an excavator blade

Abstract

The application provides a hydraulic system and control method of a bulldozer blade of an excavator, and the hydraulic system comprises a main pump, a main valve group, a bulldozer oil cylinder and a bidirectional balance valve; the main valve group comprises a bulldozer valve, a straight-line walking valve, a left walking valve, a right walking valve, a first mid-position cut-off valve and a second mid-position cut-off valve; the main valve group is provided with a first oil supply port and a second oil supply port, the second oil supply port is connected with the right walking valve and also connected with the straight-line walking valve; the first oil supply port is connected with the straight-line walking valve; the straight-line walking valve is connected with the left walking valve; the straight-line walking valve is connected with the bulldozer valve and also connected with the second mid-position cut-off valve; two oil ports of the right walking valve are respectively used for connecting right walking motors, the right walking valve is connected with the second mid-position cut-off valve, two oil ports of the left walking valve are respectively used for connecting left walking motors, and the left walking valve is connected with the first mid-position cut-off valve; the application can avoid sudden falling of the bulldozer blade and deviation during execution of a combined action of the bulldozer blade and walking.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of hydraulic technology of construction machinery, and particularly relates to a hydraulic system and control method of a bulldozing bucket of an excavator. BACKGROUND

[0002] With the development and expansion of the excavator market, the application of excavators is becoming more and more common, and the working conditions are becoming more and more rich, and the bulldozing bucket becomes one of the auxiliary tools with a higher frequency of use; however, the current control mode of the bulldozing bucket is prone to sudden falling and deviation when the bulldozing bucket and walking are simultaneously used.

[0003] Therefore, there is an urgent need for a hydraulic system and control method of a bulldozing bucket of an excavator, which can avoid sudden falling of the bulldozing bucket and deviation when the bulldozing bucket and walking are simultaneously used. SUMMARY

[0004] The present application aims to provide a hydraulic system and control method of a bulldozing bucket of an excavator, which aims to solve the technical problem of sudden falling and deviation when a composite action is performed in the conventional hydraulic control mode of the bulldozing bucket.

[0005] To achieve the above-mentioned purpose, in a first aspect, the present application provides a hydraulic system of a bulldozing bucket of an excavator, comprising: a main pump, a main valve group connected with the main pump, a bulldozing cylinder connected with the main valve group, and a bidirectional balance valve arranged between the main valve group and the bulldozing cylinder.

[0006] The main valve group comprises a bulldozing valve for controlling lifting / lowering of the bulldozing cylinder, a straight-line walking valve for controlling straight-line walking in a composite action, a left walking valve for controlling a left walking motor of the excavator, a right walking valve for controlling right walking of the excavator, and first and second mid-position cut-off valves; the main valve group is provided with first and second oil supply ports connected with the main pump; the bidirectional balance valve comprises first and second one-way balance valves which are pilot-controlled with each other.

[0007] The second oil supply port is connected with sixth and seventh oil ports of the right walking valve, and is also connected with a third oil port of the straight-line walking valve;

[0008] The first oil supply port is connected with a fourth oil port of the straight-line walking valve;

[0009] A second oil port of the straight-line walking valve is connected with sixth and seventh oil ports of the left walking valve;

[0010] A first oil port of the straight-line walking valve is connected with a fourth oil port of the bulldozing valve, and is also connected with a second oil port of the second mid-position cut-off valve;

[0011] The first and second oil ports of the right travel valve are respectively connected with two working oil ports of a right travel motor, the third oil port of the right travel valve is connected with the second oil port of the second neutral cut valve, the first oil port of the second neutral cut valve is connected with the third oil port of the bulldozer valve,

[0012] The third and fourth oil ports of the left travel valve are respectively connected with two working oil ports of a left travel motor, the second oil port of the left travel valve is connected with the second oil port of the first neutral cut valve, the first oil port of the first neutral cut valve is connected with the second oil port of the bulldozer valve,

[0013] The first oil port of the bulldozer valve is connected with the conducting end of the first one-way balance valve, the far end of the first one-way balance valve is connected with the rodless cavity of a bulldozer cylinder; the second oil port of the bulldozer valve is connected with the conducting end of the second one-way balance valve, the far end of the second one-way balance valve is connected with the rod cavity of the bulldozer cylinder.

[0014] As a further improvement of the above-mentioned scheme, the hydraulic system further comprises a pilot control handle, and the main valve group is further provided with a shuttle valve, and the valve block of the main valve group is further provided with a plurality of pilot oil ports;

[0015] The bulldozer valve, the straight travel valve, the left travel valve, the right travel valve, the first neutral cut valve and the second neutral cut valve are all pilot-operated hydraulic control valves;

[0016] The pilot control handle has a first pilot oil port and a second pilot oil port, the first pilot oil port is connected with the first pilot oil port of the bulldozer valve and the first oil port of the shuttle valve;

[0017] The second pilot oil port is connected with the second pilot oil port of the bulldozer valve and the second oil port of the shuttle valve;

[0018] The third oil port of the shuttle valve is connected with the pilot oil ports of the first and second neutral cut valves respectively, and is further connected with the pilot oil port of the straight travel valve through the first one-way valve;

[0019] The first and second pilot oil ports of the left travel valve are respectively connected with the pilot oil ports on the valve block;

[0020] The first and second pilot oil ports of the right travel valve are respectively connected with the pilot oil ports on the valve block.

[0021] As a further improvement of the above-mentioned scheme, the fifth oil port of the right travel valve is connected with a return oil circuit, the fourth and eighth oil ports thereof are respectively connected with the pilot oil ports on the valve block;

[0022] The eighth oil port of the left walking valve is connected with the oil return oil path, and the fifth oil port and the first oil port are respectively connected with the pilot oil ports on the valve block.

[0023] As a further improvement of the above-mentioned scheme, the main valve group further comprises a main relief valve, the first oil supply port is connected with the main relief valve through a second one-way valve, and the second oil supply port is connected with the main relief valve through a third one-way valve.

[0024] As a further improvement of the above-mentioned scheme, the bulldozing valve is a middle-positioned three-position four-way valve.

[0025] The straight-line walking valve is a two-position four-way valve.

[0026] The left walking valve and the right walking valve are both middle-positioned three-position eight-way valves.

[0027] The first middle-positioned cut-off valve and the second middle-positioned cut-off valve are both two-position two-way valves.

[0028] As a further improvement of the above-mentioned scheme, the first oil port of the bidirectional balance valve is connected with the conducting end of the first one-way balance valve, the third oil port of the bidirectional balance valve is connected with the end of the first one-way balance valve away from the conducting end,

[0029] The second oil port of the bidirectional balance valve is connected with the conducting end of the second one-way balance valve, and the fourth oil port of the bidirectional balance valve is connected with the end of the second one-way balance valve away from the conducting end.

[0030] Preferably, the first one-way balance valve comprises a fourth one-way valve and a first pilot relief valve connected in parallel.

[0031] The second one-way balance valve comprises a fifth one-way valve and a second pilot relief valve connected in parallel, and the first pilot relief valve and the second pilot relief valve are connected in staggered pilot control.

[0032] As a further improvement of the above-mentioned scheme, a multi-connection three-way valve is further arranged between the pilot control handle and the main valve group, and a first pressure sensor and a second pressure sensor are arranged on the multi-connection three-way valve, and are respectively used for monitoring the pilot pressure, so as to control the oil supply passage of the main pump through the first oil supply port and the second oil supply port.

[0033] In a second aspect, the application further provides a control method of the hydraulic system of the excavator bulldozing shovel.

[0034] When the bulldozing shovel is lowered:

[0035] The main pump flows high-pressure oil through the second oil inlet, the right traveling valve, the fourth oil inlet of the bulldozing valve, the first oil outlet of the bulldozing valve, the first one-way balance valve of the bidirectional balance valve, and the rodless cavity of the bulldozing oil cylinder to lower the bulldozing blade, and the overflow valve of the second one-way balance valve opens reverse flow to return to the oil tank.

[0036] When the bulldozing blade is lifted:

[0037] The main pump flows high-pressure oil through the second oil inlet, the right traveling valve, the fourth oil inlet of the bulldozing valve, the second oil outlet of the bulldozing valve, the second one-way balance valve of the bidirectional balance valve, and the rod cavity of the bulldozing oil cylinder to lift the bulldozing blade, and the overflow valve of the first one-way balance valve opens reverse flow to return to the oil tank.

[0038] When the bulldozing blade is lowered and the straight-line traveling is combined:

[0039] The main pump flows high-pressure oil through the second oil inlet, the sixth oil inlet of the right traveling valve, and the working oil inlet of the right traveling motor, and flows high-pressure oil through the second oil inlet, the third oil inlet of the straight-line traveling valve, the seventh oil inlet of the left traveling valve, and the working oil inlet of the left traveling motor.

[0040] The main pump flows high-pressure oil through the first oil inlet, the fourth oil inlet of the straight-line traveling valve, the fourth oil inlet of the bulldozing valve, the first oil outlet of the bulldozing valve, the first one-way balance valve of the bidirectional balance valve, and the rodless cavity of the bulldozing oil cylinder to lower the bulldozing blade, and the overflow valve of the second one-way balance valve opens reverse flow to return to the oil tank.

[0041] When the bulldozing blade is lifted and the straight-line traveling is combined:

[0042] The main pump flows high-pressure oil through the second oil inlet, the sixth oil inlet of the right traveling valve, and the working oil inlet of the right traveling motor, and flows high-pressure oil through the second oil inlet, the third oil inlet of the straight-line traveling valve, the seventh oil inlet of the left traveling valve, and the working oil inlet of the left traveling motor.

[0043] The main pump flows high-pressure oil through the first oil inlet, the fourth oil inlet of the straight-line traveling valve, the fourth oil inlet of the bulldozing valve, the second oil outlet of the bulldozing valve, the second one-way balance valve of the bidirectional balance valve, and the rod cavity of the bulldozing oil cylinder to lift the bulldozing blade, and the overflow valve of the first one-way balance valve opens reverse flow to return to the oil tank.

[0044] As a further improvement of the above scheme, before the main pump supplies oil, the spool of each valve is moved to the corresponding working position under the action of the pilot control oil;

[0045] When the dozer blade is lowered:

[0046] The first pilot oil port of the dozer valve moves the spool to the right under the pressure of the pilot control oil; at the same time, the pilot control oil flows through the shuttle valve and the first one-way valve in turn to push the spool of the straight-line walking valve to move to the right; the spool of the first mid-cut valve moves to the left, and the spool of the second mid-cut valve moves to the right, realizing mid-cut;

[0047] When the dozer blade is lifted:

[0048] The second pilot oil port of the dozer valve moves the spool to the left under the pressure of the pilot control oil; at the same time, the pilot control oil flows through the shuttle valve and the first one-way valve in turn to push the spool of the straight-line walking valve to move to the right; the spool of the first mid-cut valve moves to the left, and the spool of the second mid-cut valve moves to the right, realizing mid-cut;

[0049] When the dozer blade is lowered and the straight-line walking is combined:

[0050] The first pilot oil port of the dozer valve moves the spool to the right under the pressure of the pilot control oil; at the same time, the pilot control oil flows through the shuttle valve and the first one-way valve in turn to push the spool of the straight-line walking valve to move to the right; the spool of the first mid-cut valve moves to the left, and the spool of the second mid-cut valve moves to the right, realizing mid-cut;

[0051] The second pilot oil port of the right walking valve moves the spool to the left under the pressure of the pilot control oil, and at the same time, the first pilot oil port of the left walking valve moves the spool to the right under the pressure of the pilot control oil;

[0052] When the dozer blade is lifted and the straight-line walking is combined:

[0053] The second pilot oil port of the dozer valve moves the spool to the left under the pressure of the pilot control oil; at the same time, the pilot control oil flows through the shuttle valve and the first one-way valve in turn to push the spool of the straight-line walking valve to move to the right; the spool of the first mid-cut valve moves to the left, and the spool of the second mid-cut valve moves to the right, realizing mid-cut;

[0054] The second pilot oil port of the right walking valve moves the spool to the left under the pressure of the pilot control oil, and at the same time, the first pilot oil port of the left walking valve moves the spool to the right under the pressure of the pilot control oil.

[0055] Due to the adoption of the above technical scheme, the present application has the following beneficial effects:

[0056] The hydraulic system of the excavator bulldozing blade provided by the application comprises a bidirectional balance valve arranged between a main valve group and a bulldozing oil cylinder, wherein the bidirectional balance valve comprises a first one-way balance valve and a second one-way balance valve which are pilot-controlled with each other, the first one-way balance valve is arranged between the bulldozing valve and a rodless cavity of the bulldozing oil cylinder, and the second one-way balance valve is arranged between the bulldozing valve and a rod cavity of the bulldozing oil cylinder. By arranging the first one-way balance valve and the second one-way balance valve which are pilot-controlled with each other, the movement of the bulldozing oil cylinder can be prevented from being out of control, and the oil cylinder can be prevented from falling suddenly, and meanwhile, the bidirectional balance valve can also enable the bulldozing oil cylinder to realize the pressure maintaining function, so that the excavator can continue to perform the bulldozing operation.

[0057] In addition, in the hydraulic system of the application, a straight walking valve, a shuttle valve and a first one-way valve connected with a third oil port of the shuttle valve are arranged. When the excavator needs to perform the straight walking and the bulldozing blade compound operation, after the pilot control oil is opened, the shuttle valve and the first one-way valve are connected under the corresponding pilot pressure to make the valve core of the straight walking valve, the left walking valve and the right walking valve move to the corresponding working positions, so that the straight walking and the bulldozing blade compound operation can be normally performed.

[0058] The first one-way valve added at the pilot oil port PTa of the straight walking valve can also meet the requirements of one or any two of the four groups of operations of the swing arm, the bucket rod, the bucket and the rotation, or the compound operation, and ensure that the pilot pressure can push the valve core of the straight walking valve when the walking operation is simultaneously performed, so that the excavator can perform the straight walking without deviation. BRIEF DESCRIPTION OF DRAWINGS

[0059] In order to more clearly illustrate the technical solutions in the embodiments of the application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description are only some embodiments of the application, and for those skilled in the art, other drawings can also be obtained from the structures shown in the drawings without creative labor.

[0060] Figure 1 FIG. 1 is a schematic diagram of the hydraulic system of the excavator bulldozing blade disclosed by the application;

[0061] Figure 2 FIG. 2 is a schematic diagram of the I direction of the hydraulic system of the excavator bulldozing blade disclosed by the application; Figure 1

[0062] FIG. 3 is a schematic diagram of the J direction of the hydraulic system of the excavator bulldozing blade disclosed by the application; Figure 3 Figure 1 FIG. 4 is a schematic diagram of the K direction of the hydraulic system of the excavator bulldozing blade disclosed by the application.

[0063] Figure 4 Figure 1

[0064] ​​​Reference signs:

[0065] 1, main pump; 2, main valve group; 21, bulldozing valve; 22, straight traveling valve; 23, left traveling valve; 24, right traveling valve; 25, first neutral cut-off valve; 26, second neutral cut-off valve; 27, shuttle valve; 28, main relief valve; 29, first check valve;

[0066] 3, bulldozing oil cylinder; 4, bidirectional balance valve; 41, first check balance valve; 411, fourth check valve; 412, first pilot relief valve; 42, second check balance valve; 421, fifth check valve; 422, second pilot relief valve;

[0067] 5, pilot control handle; 6, second check valve; 7, third check valve; 8, multi-union valve; 81, first pressure sensor; 82, second pressure sensor;

[0068] P1, first oil supply port; P2, second oil supply port.

[0069] The implementation, functional features and advantages of the present application will be further described with reference to the embodiments in combination with the accompanying drawings. DETAILED DESCRIPTION

[0070] The technical solutions in the embodiments of the present application will be clearly and completely described below in combination with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work under the premise that the embodiments in the present application belong to the scope of protection of the present application.

[0071] It should be noted that all directional indications (such as up, down, …) in the embodiments of the present application are only used to explain the relative position relationship, movement condition, etc. between components in a certain posture (as shown in the drawings), and if the certain posture changes, the directional indications also change accordingly.

[0072] In addition, the description such as "first", "second" and the like in the present application is only for the purpose of description, and cannot be understood as indicating or implying the relative importance of the indicated technical features or implicitly indicating the number of the indicated technical features. Therefore, the features limited by "first", "second" can explicitly or implicitly include at least one of the features.

[0073] In addition, the technical solutions of each embodiment of the present application can be combined with each other, but it must be based on the fact that a person skilled in the art can realize it, and when the combination of technical solutions appears contradictory or unachievable, it should be considered that the combination of technical solutions does not exist, and is not within the scope of protection required by the present application.

[0074] Embodiment 1:

[0075] Referring to Figures 1-4 The present application provides a hydraulic system of a bulldozer blade of an excavator, comprising a main pump 1, a main valve group 2 connected with the main pump 1, a bulldozer oil cylinder 3 connected with the main valve group 2, and a bidirectional balance valve 4 arranged between the main valve group 2 and the bulldozer oil cylinder 3.

[0076] The main valve group 2 comprises a bulldozer valve 21 for controlling the bulldozer oil cylinder 3 to lift / lower, a straight travel valve 22, a left travel valve 23 for controlling a left travel motor of the excavator, a right travel valve 24 for controlling the excavator to travel to the right, and a first mid-position cut-off valve 25 and a second mid-position cut-off valve 26; the main valve group 2 is provided with a first oil supply port P1 and a second oil supply port P2 connected with the main pump 1; the bidirectional balance valve 4 comprises a first one-way balance valve 41 and a second one-way balance valve 42 which are pilot-controlled with each other.

[0077] Specifically, in the embodiment, the bulldozer valve 21 is a mid-position three-position four-way valve; the straight travel valve 22 is a two-position four-way valve; the left travel valve 23 and the right travel valve 24 are both mid-position three-position eight-way valves.

[0078] The first mid-position cut-off valve 25 and the second mid-position cut-off valve 26 are both two-position two-way valves.

[0079] The second oil supply port P2 is connected with a sixth oil port and a seventh oil port of the right travel valve 24, and is also connected with a third oil port of the straight travel valve 22.

[0080] The first oil supply port P1 is connected with a fourth oil port of the straight travel valve 22.

[0081] A second oil port of the straight travel valve 22 is connected with a sixth oil port and a seventh oil port of the left travel valve 23.

[0082] A first oil port of the straight travel valve 22 is connected with a fourth oil port of the bulldozer valve 21, and is also connected with a second oil port of the second mid-position cut-off valve 26.

[0083] A first oil port and a second oil port of the right travel valve 24 are respectively used for being connected with two working oil ports of a right travel motor, a third oil port of the right travel valve 24 is connected with a second oil port of the second mid-position cut-off valve 26, a first oil port of the second mid-position cut-off valve 26 is connected with a third oil port of the bulldozer valve 21,

[0084] The third oil port and the fourth oil port of the left walking valve 23 are respectively used for connecting with two working oil ports of a left walking motor, the second oil port of the left walking valve 23 is connected with the second oil port of the first neutral cut-off valve 25, the first oil port of the first neutral cut-off valve 25 is connected with the second oil port of the bulldozing valve 21,

[0085] The first oil port of the bulldozing valve 21 is connected with the conducting end of the first one-way balance valve 41, the far end of the first one-way balance valve 41 is connected with the rodless cavity of the bulldozing cylinder 3; the second oil port of the bulldozing valve 21 is connected with the conducting end of the second one-way balance valve 42, the far end of the second one-way balance valve 42 is connected with the rod cavity of the bulldozing cylinder 3; the first oil port of the two-way balance valve 4 is connected with the conducting end of the first one-way balance valve 41, the third oil port of the two-way balance valve 4 is connected with the far end of the first one-way balance valve 41, the second oil port of the two-way balance valve 4 is connected with the conducting end of the second one-way balance valve 42, and the fourth oil port of the two-way balance valve 4 is connected with the far end of the second one-way balance valve 42;

[0086] The first one-way balance valve 41 comprises a fourth one-way valve 411 and a first pilot relief valve 412 connected in parallel;

[0087] The second one-way balance valve 42 comprises a fifth one-way valve 421 and a second pilot relief valve 422 connected in parallel, and the first pilot relief valve 412 and the second pilot relief valve 422 are interlaced pilot control connection;

[0088] In the present application, the two-way balance valve 4 is arranged between the main valve valve group 2 and the bulldozing cylinder 3, and the two-way balance valve 4 comprises the first one-way balance valve 41 and the second one-way balance valve 42 which are pilot controlled with each other, the first one-way balance valve 41 is arranged between the bulldozing valve 21 and the rodless cavity of the bulldozing cylinder 3, and the second one-way balance valve 42 is arranged between the bulldozing valve 21 and the rod cavity of the bulldozing cylinder 3, through the arrangement of the first one-way balance valve 41 and the second one-way balance valve 42 which are pilot controlled with each other, the movement of the bulldozing cylinder 3 can be prevented from being out of control, and the cylinder can be prevented from falling suddenly, at the same time, the two-way balance valve 4 can also enable the bulldozing cylinder 3 to realize the pressure maintaining function, so that the excavator can continue to perform the bulldozing operation;

[0089] In addition, the hydraulic system of the present application is further provided with a straight traveling valve 22, a shuttle valve 27, and a first check valve 29 connected with the third oil port of the shuttle valve 27, when the excavator needs to perform the combined action of straight traveling and the dozing blade, after the pilot control oil is opened, the shuttle valve 27 and the first check valve 29 are connected under the corresponding pilot pressure to make the corresponding channels conductive, so that the valve cores of the straight traveling valve 22, the left traveling valve 23 and the right traveling valve 24 are moved to the corresponding working positions, thereby ensuring that the combined action of the dozing blade and the straight traveling can be normally performed without deviation.

[0090] As a preferred embodiment, the hydraulic system further comprises a pilot control handle 5, the main valve group 2 is further provided with a shuttle valve 27, and the valve block of the main valve group 2 is further provided with a plurality of pilot oil ports (such as XBtr, XAtr, XBtl, XAtl, etc.);

[0091] The dozing valve 21, the straight traveling valve 22, the left traveling valve 23, the right traveling valve 24, the first mid-position cut-off valve 25 and the second mid-position cut-off valve 26 are all pilot-controlled hydraulic valves;

[0092] The pilot control handle 5 has a first pilot oil port and a second pilot oil port, the first pilot oil port is connected with the first pilot oil port of the dozing valve 21, and is also connected with the first oil port of the shuttle valve 27;

[0093] The second pilot oil port is connected with the second pilot oil port of the dozing valve 21, and is also connected with the second oil port of the shuttle valve 27;

[0094] The third oil port of the shuttle valve 27 is connected with the pilot oil ports of the first mid-position cut-off valve 25 and the second mid-position cut-off valve 26 respectively, and is also connected with the pilot oil port of the straight traveling valve 22 through the first check valve 29;

[0095] The first pilot oil port and the second pilot oil port of the left traveling valve 23 are connected with the pilot oil ports on the valve block respectively;

[0096] The first pilot oil port and the second pilot oil port of the right traveling valve 24 are connected with the pilot oil ports on the valve block respectively;

[0097] The fifth oil port of the right traveling valve 24 is connected with the oil return oil circuit, and the fourth oil port and the eighth oil port thereof are connected with the pilot oil ports on the valve block respectively;

[0098] The eighth oil port of the left traveling valve 23 is connected with the oil return oil circuit, and the fifth oil port and the first oil port thereof are connected with the pilot oil ports on the valve block respectively;

[0099] Specifically, the bulldozing valve 21 has three working positions, a lowering working position, a bulldozing middle position and a lifting working position, in the bulldozing middle position, the four oil ports are not communicated with each other, in the lowering working position, the first oil port is communicated with the fourth oil port, and the second oil port is communicated with the third oil port;

[0100] The first middle cut-off valve 25 and the second middle cut-off valve 26 have the same structure, and each has a communication working position and a cut-off working position, in the communication working position, the first oil port and the second oil port are communicated with each other, in the switching working position, the first oil port and the second oil port are not communicated with each other;

[0101] Referring to Figures 2-4 , the straight-line walking valve 22 has a first working position and a second working position, in the first working position, the first oil port and the fourth oil port are communicated with each other, and the second oil port and the third oil port are communicated with each other, in the second working position, the first oil port and the third oil port are communicated with each other, and the second oil port and the fourth oil port are communicated with each other;

[0102] The right walking valve 24 has a first working position, a middle position and a second working position, in the middle position, the first oil port and the second oil port are both communicated with the fifth oil port, and the fifth oil port is connected with an oil tank, the third oil port is communicated with the seventh oil port, the fourth oil port is communicated with the eighth oil port, and the sixth oil port is not connected with other oil ports;

[0103] When only the bulldozing shovel is operated, the right walking valve 24 is in the middle position;

[0104] In the first working position, the first oil port is communicated with the sixth oil port, the second oil port is communicated with the fifth oil port, and the third oil port, the seventh oil port, the fourth oil port and the eighth oil port are not communicated with each other;

[0105] In the second working position, the first oil port is communicated with the fifth oil port, the second oil port is communicated with the sixth oil port, and the third oil port, the seventh oil port, the fourth oil port and the eighth oil port are not communicated with each other;

[0106] The left walking valve 23 has a first working position, a middle position and a second working position, in the middle position, the third oil port and the fourth oil port are both communicated with the eighth oil port, and the eighth oil port is connected with an oil tank, the second oil port is communicated with the sixth oil port, the first oil port is communicated with the fifth oil port, and the seventh oil port is not connected with other oil ports;

[0107] When only the bulldozing shovel is operated, the left walking valve 23 is in the middle position;

[0108] In the first working position, the third oil port is communicated with the eighth oil port, the fourth oil port is communicated with the seventh oil port, and the first oil port, the second oil port, the fifth oil port and the sixth oil port are not communicated with each other;

[0109] In the second working position, the third oil port is communicated with the seventh oil port, the fourth oil port is communicated with the eighth oil port, and the first oil port, the second oil port, the fifth oil port and the sixth oil port are not communicated with each other;

[0110] When the excavator is in the straight or backward movement, the pilot control oil pushes the valve core to move to the corresponding working position;

[0111] The pilot control handle 5 and the main valve valve group 2 are further provided with a multi-connection three-way valve 8, the multi-connection three-way valve 8 is provided with a first pressure sensor 81 and a second pressure sensor 82, and is used for monitoring the pilot pressure respectively, so that the main pump 1 controls the oil supply channel of the first oil supply port P1 and the second oil supply port P2.

[0112] As a further improvement of the above scheme, the main valve valve group 2 further comprises a main overflow valve 28, the first oil supply port P1 is connected with the main overflow valve 28 through the second one-way valve 6, and the second oil supply port P2 is connected with the main overflow valve 28 through the third one-way valve 7; specifically, in the embodiment, the main overflow valve 28 is a pilot overflow valve, the arrangement of the main overflow valve 28 can keep the pressure in the hydraulic system stable, so that the accident can be avoided; in cooperation with the one-way valve and the two oil supply ports, the pressure in the system is further ensured to be stable.

[0113] Embodiment 2:

[0114] The application further provides a control method of the hydraulic system of the excavator bulldozing blade, and the steps of the method comprise:

[0115] When the bulldozing blade is lowered:

[0116] The pilot control handle 5 is pushed to move forward, the first pilot oil port of the bulldozing valve 21 is pushed to move right (so that the bulldozing valve 21 is in the lowering working position) under the pressure of the pilot control oil, and the pilot control oil sequentially flows through the shuttle valve 27 and the first one-way valve 29 to push the valve core of the straight-line walking valve 22 to move right (so that the straight-line walking valve 22 is in the first working position); at this time, the valve core XBp1 of the first mid-position cut-off valve 25 connected with the pilot oil port PTa moves left (so that the first mid-position cut-off valve 25 is in the cut-off working position), the valve core XBp2 of the second mid-position cut-off valve 26 moves right (so that the second mid-position cut-off valve 26 is in the cut-off working position), and the mid-position cut-off is realized.

[0117] The first pressure sensor 81 on the multi-union three-way valve 8 monitors the pilot pressure, sends an electric signal to the controller to control the main pump 1 to supply oil to the second oil supply port P2; the main pump 1 supplies high-pressure oil through the second oil supply port P2 to the fourth oil port of the bulldozer valve 21 through the right travel valve 24, and then flows out from the second oil port of the bulldozer valve 21 to enter the first one-way balance valve 41 of the bidirectional balance valve 4, and then enters the rodless cavity of the bulldozer cylinder 3 to realize the lowering of the bulldozer blade, and the overflow valve of the second one-way balance valve 42 controlled by each other opens the reverse flow to return to the oil tank; Specifically, the high-pressure oil flows into the first oil port of the bidirectional balance valve 4 through the fourth one-way valve 411, and then flows into the rodless cavity of the bulldozer cylinder 3 through the third oil port of the bidirectional balance valve 4, thereby maintaining the load to prevent reverse movement, and the piston rod of the bulldozer cylinder 3 pushes out the bulldozer blade to lower, and at the same time, when the second pilot overflow valve 422 is applied with pilot pressure on the cross pilot oil way, the second pilot overflow valve 422 is opened to realize reverse flow and return to the oil tank; In this way, by using the high-pressure oil entering the rodless cavity as the pilot control oil of the second pilot overflow valve 422, the second pilot overflow valve 422 is opened, and the hydraulic oil can be slowly returned by adjusting the pilot pressure, thereby preventing the sudden drop of the bulldozer cylinder 3;

[0118] When the bulldozer blade is lifted:

[0119] When the bulldozer blade is lifted:

[0120] The second pressure sensor 82 on the multi-union three-way valve 8 monitors the pilot pressure, sends an electric signal to the controller to control the main pump 1 to supply oil to the second oil supply port P2; the main pump 1 supplies high-pressure oil through the second oil supply port P2 to the fourth oil port of the bulldozer valve 21 through the right travel valve 24, and then flows out from the second oil port of the bulldozer valve 21 to enter the second one-way balance valve 42 of the bidirectional balance valve 4, and then enters the rodless cavity of the bulldozer cylinder 3 to realize the lowering of the bulldozer blade, and the overflow valve of the second one-way balance valve 42 controlled by each other opens the reverse flow to return to the oil tank; Specifically, the high-pressure oil flows into the first oil port of the bidirectional balance valve 4 through the fourth one-way valve 411, and then flows into the rodless cavity of the bulldozer cylinder 3 through the third oil port of the bidirectional balance valve 4, thereby maintaining the load to prevent reverse movement, and the piston rod of the bulldozer cylinder 3 pushes out the bulldozer blade to lower, and at the same time, when the second pilot overflow valve 422 is applied with pilot pressure on the cross pilot oil way, the second pilot overflow valve 422 is opened to realize reverse flow and return to the oil tank; In this way, by using the high-pressure oil entering the rodless cavity as the pilot control oil of the second pilot overflow valve 422, the second pilot overflow valve 422 is opened, and the hydraulic oil can be slowly returned by adjusting the pilot pressure, thereby preventing the sudden drop of the bulldozer cylinder 3;

[0121] Specifically, the high-pressure oil flowing into the second oil port of the bidirectional balance valve 4 flows into the rod cavity of the dozer oil cylinder 3 through the fourth oil port of the bidirectional balance valve 4 through the fifth one-way valve 421, and the load is prevented from moving backward, the piston rod of the dozer oil cylinder 3 is retracted to lift the dozer blade, and at the same time, when the first pilot overflow valve 412 is applied with a pilot pressure on the intersecting pilot oil path, the first pilot overflow valve 412 is opened to realize reverse flow and return to the tank; in this way, by taking the high-pressure oil entering the rod cavity as the pilot control oil of the first pilot overflow valve 412, the first pilot overflow valve 412 is opened, and the hydraulic oil can slowly return after the adjustment of the pilot pressure, so as to prevent the dozer oil cylinder 3 from suddenly falling;

[0122] When the dozer blade is lowered and the straight-line walking is combined:

[0123] Different from the dozer blade lowering single action, when the two combined actions are performed at the same time, the controller controls the main pump 1 to supply oil to the first oil supply port P1 and the second oil supply port P2 at the same time, the oil path corresponding to the first oil supply port P1 supplies the dozer blade lowering action, specifically, the dozer valve 21 is pushed forward, the valve core of the dozer valve 21 moves to the right under the pressure of the pilot control oil (so that it is in the lowering working position); at the same time, the pilot control oil flows through the shuttle valve 27 and the first one-way valve 29 in turn to push the valve core of the straight-line walking valve 22 to move to the right (so that it is in the first working position); at this time, the valve core XBp1 of the first mid-position cut-off valve 25 connected with the pilot oil port PTa moves to the left (so that it is in the cut-off working position), the valve core XBp2 of the second mid-position cut-off valve 26 moves to the right (so that it is in the cut-off working position), and the mid-position cut-off is realized.

[0124] The oil path corresponding to the second oil supply port P2 supplies the walking motors on both sides, when walking forward at the same time, the second pilot oil port XBtr of the right walking valve 24 moves to the left under the pressure of the pilot control oil (so that it is in the second working position), and the second oil supply port P2 communicates with the pilot oil port Btr; at the same time, the first pilot oil port XBtl of the left walking valve 23 moves to the right under the pressure of the pilot control oil (so that it is in the first working position); the second oil supply port P2 communicates with the pilot oil port BtL; walking will not deviate when the dozer blade is lowered under the action of the straight-line walking valve 22; when the dozer blade is lowered and walks backward at the same time, the same applies, and will not be described again.

[0125] The main pump 1 enters the sixth oil port of the right walking valve 24 through the second oil supply port P2, and then enters the working oil port of the right walking motor through the second oil port; at the same time, the main pump 1 enters the third oil port of the straight-line walking valve 22 through the second oil supply port P2, and then enters the seventh oil port of the left walking valve 23 through the second oil port, and then enters the working oil port of the left walking motor through the fourth oil port;

[0126] The main pump 1 supplies high-pressure oil to the fourth oil port of the straight travel valve 22 through the first oil port P1, and then to the fourth oil port of the dozer valve 21 through the first oil port of the straight travel valve 22, and then to the first one-way balance valve 41 of the two-way balance valve 4 from the first oil port of the dozer valve 21, and then to the rodless cavity of the dozer oil cylinder 3, thereby realizing the lowering of the dozer blade, and the overflow valve of the second one-way balance valve 42 opens in reverse flow to the oil tank.

[0127] Specifically, the high-pressure oil flows into the first oil port of the two-way balance valve 4, and then flows into the rodless cavity of the dozer oil cylinder 3 through the third oil port of the two-way balance valve 4 through the fourth one-way valve 411, thereby preventing reverse movement, and the piston rod of the dozer oil cylinder 3 pushes the dozer blade to lower, and when the second pilot overflow valve 422 is applied with pilot pressure on the cross pilot oil way, the second pilot overflow valve 422 opens to realize reverse flow and return to the oil tank; in this way, the high-pressure oil entering the rodless cavity serves as the pilot control oil of the second pilot overflow valve 422, and after the second pilot overflow valve 422 opens, the hydraulic oil can slowly return through the adjustment of the pilot pressure, thereby preventing the sudden drop of the dozer oil cylinder 3.

[0128] When the dozer blade is lifted and the straight travel is combined:

[0129] Different from the single action of lowering the dozer blade, when the two combined actions are performed at the same time, the controller controls the main pump 1 to supply oil to the first oil port P1 and the second oil port P2 at the same time, the oil path corresponding to the first oil port P1 supplies the lifting action of the dozer blade, specifically, the dozer valve 21 is pushed to move backward, the second pilot oil port of the dozer valve 21 moves to the left under the pressure of the pilot control oil (so that it is in the lifting working position); at the same time, the pilot control oil flows through the shuttle valve 27 and the first one-way valve 29 in turn to push the valve core of the straight travel valve 22 to move to the right (so that it is in the first working position); at this time, the valve core XBp1 of the first mid-position cut-off valve 25 connected with the pilot oil port PTa moves to the left (so that it is in the cut-off working position), and the valve core XBp2 of the second mid-position cut-off valve 26 moves to the right (so that it is in the cut-off working position), thereby realizing the mid-position cut-off.

[0130] The oil path corresponding to the second oil port P2 supplies the travel motors on both sides, when traveling forward at the same time, the second pilot oil port XBtr of the right travel valve 24 moves to the left under the pressure of the pilot control oil (so that it is in the second working position), and the second oil port P2 communicates with the pilot oil port Btr; at the same time, the first pilot oil port XBtl of the left travel valve 23 moves to the right under the pressure of the pilot control oil (so that it is in the first working position); the second oil port P2 communicates with the pilot oil port BtL; the travel will not deviate when the dozer blade is lowered under the action of the straight travel valve 22; when the dozer blade is lifted and travels backward at the same time, the same applies, and it will not be repeated here.

[0131] The main pump 1 enters the sixth oil port of the right traveling valve 24 through the second oil supply port P2, and then enters the working oil port of the right traveling motor through the second oil port of the right traveling valve 24; meanwhile, the main pump 1 enters the third oil port of the straight traveling valve 22 through the second oil supply port P2, and then enters the seventh oil port of the left traveling valve 23 through the second oil port of the straight traveling valve 22, and then enters the working oil port of the left traveling motor through the fourth oil port of the left traveling valve 23;

[0132] The main pump 1 enters the fourth oil port of the straight traveling valve 22 through the first oil supply port P1, and then enters the fourth oil port of the dozing valve 21 through the first oil port of the straight traveling valve 22, and then flows out from the second oil port of the dozing valve 21 to enter the second one-way balance valve 42 of the two-way balance valve 4, and then enters the rod cavity of the dozing cylinder 3 to realize the lifting of the dozing blade, and the overflow valve of the first one-way balance valve 41 controlled by each other as a pilot opens to flow reversely to the oil tank;

[0133] Specifically, the high-pressure oil flowing into the second oil port of the two-way balance valve 4 flows into the rod cavity of the dozing cylinder 3 through the fourth oil port of the two-way balance valve 4 through the fifth one-way valve 421, so as to maintain the load and prevent reverse movement, the piston rod of the dozing cylinder 3 retracts to lift the dozing blade, and when the first pilot overflow valve 412 is applied with a pilot pressure on the crossed pilot oil path, the first pilot overflow valve 412 is opened to realize reverse flow and return to the oil tank; in this way, the high-pressure oil entering the rod cavity is used as the pilot control oil of the first pilot overflow valve 412, and after the first pilot overflow valve 412 is opened, the hydraulic oil can slowly return through the adjustment of the pilot pressure, so as to prevent the sudden drop of the dozing cylinder 3;

[0134] In the present application, during the lowering and lifting of the dozing blade, the first one-way balance valve 41 and the second one-way balance valve 42 controlled by each other as a pilot in the two-way balance valve can avoid the sudden drop of the dozing blade during work;

[0135] The first one-way valve 29 flowing into the pilot oil port PTa of the straight traveling valve 22 is matched with the setting of the shuttle valve 27, and the setting can also satisfy one or any two actions or compound actions in the four actions of the swing arm, the bucket rod, the bucket and the rotation, and ensure that the pilot pressure can push the valve core of the straight traveling valve 22 when the walking action is operated at the same time, so as to ensure that the excavator can travel straight without deviation.

[0136] The above is only the preferred embodiment of the present application, and does not limit the patent range of the present application, and any equivalent structural transformation made according to the inventive concept of the present application, and the content of the specification and the drawings, or direct / indirect application in other related technical fields are included in the patent protection range of the present application.

Claims

1. A hydraulic system for a shovel blade of an excavator, characterized by, The utility model relates to a kind of hydraulic control system of bulldozer, including: Main pump, main valve group connected with the main pump, bulldozer oil cylinder connected with the main valve group, and the bidirectional balance valve between the main valve group and the bulldozer oil cylinder is arranged; The main valve group includes bulldozer valve, straight line walking valve, left walking valve, right walking valve, and first mid-position cut-off valve and second mid-position cut-off valve;The main valve group is equipped with the first oil supply port and the second oil supply port connected with the main pump, and the bidirectional balance valve includes first one-way balance valve and second one-way balance valve being pilot-controlled each other; The second oil supply port is connected with the oil port of the right walking valve, and also connected with the oil port of the straight line walking valve;The first oil supply port is connected with the oil port of the straight line walking valve; The oil port of the straight line walking valve is connected with the oil port of the left walking valve; The oil port of the straight line walking valve is connected with the oil port of the bulldozer valve, and also connected with the oil port of second mid-position cut-off valve; The first oil port and the second oil port of the right walking valve are respectively used for being connected with two working oil ports of right walking motor, the oil port of the right walking valve is connected with the oil port of the second mid-position cut-off valve, the oil port of the second mid-position cut-off valve is connected with the oil port of the bulldozer valve, The third oil port and the fourth oil port of the left walking valve are respectively used for being connected with two working oil ports of left walking motor, the oil port of the left walking valve is connected with the oil port of the first mid-position cut-off valve, the oil port of the first mid-position cut-off valve is connected with the oil port of the bulldozer valve, The first oil port of the bulldozer valve is connected with the lead-through end of the first one-way balance valve, and the remote lead-through end of the first one-way balance valve is connected with the rodless cavity of bulldozer oil cylinder;The second oil port of the bulldozer valve is connected with the lead-through end of the second one-way balance valve, and the remote lead-through end of the second one-way balance valve is connected with the rod cavity of bulldozer oil cylinder; It further includes pilot control handle, and the main valve group is further equipped with shuttle valve, and the valve block of the main valve group is further equipped with a plurality of pilot oil ports; The bulldozer valve, the straight line walking valve, the left walking valve, the right walking valve, the first mid-position cut-off valve and the second mid-position cut-off valve are all pilot-operated hydraulic control valve; The pilot control handle has first pilot oil port and second pilot oil port, and the first pilot oil port is connected with the first pilot oil port of the bulldozer valve, and also connected with the first oil port of the shuttle valve; The second pilot oil port is connected with the second pilot oil port of the bulldozer valve, and also connected with the second oil port of the shuttle valve; The third oil port of the shuttle valve is connected with the pilot oil port of the first mid-position cut-off valve and the second mid-position cut-off valve respectively, and also connected with the pilot oil port of the straight line walking valve through first one-way valve; The first pilot oil port and the second pilot oil port of the left walking valve are respectively connected with the pilot oil port on the valve block; The first pilot oil port and the second pilot oil port of the right walking valve are respectively connected with the pilot oil port on the valve block.

2. A hydraulic system for an excavator blade according to claim 1, wherein The fifth oil port of the right walking valve is connected with return oil circuit, and the fourth oil port and the eighth oil port thereof are respectively connected with the pilot oil port on the valve block; The eighth oil port of the left walking valve is connected with return oil circuit, and the fifth oil port and the first oil port thereof are respectively connected with the pilot oil port on the valve block.

3. A hydraulic system for an excavator bucket according to claim 1 or 2, characterised in that, The main valve group further comprises a main relief valve, the first oil supply port is connected with the main relief valve through a second one-way valve, and the second oil supply port is connected with the main relief valve through a third one-way valve.

4. A hydraulic system for an excavator bucket according to claim 1 or 2, wherein The dozer valve is a three-position four-way valve in the middle position; The straight traveling valve is a two-position four-way valve; The left traveling valve and the right traveling valve are both three-position eight-way valves in the middle position; The first and second middle position cut-off valves are both two-position two-way valves.

5. The hydraulic system for an excavator blade according to claim 1 or 2, wherein The first one-way balance valve comprises a fourth one-way valve and a first pilot relief valve connected in parallel; The second one-way balance valve comprises a fifth one-way valve and a second pilot relief valve connected in parallel, and the first and second pilot relief valves are cross-pilot control connected with each other.

6. A hydraulic system for an excavator blade according to claim 1 or 2, wherein A multi-connection three-way valve is further arranged between the pilot control handle and the main valve group, and a first pressure sensor and a second pressure sensor are arranged on the multi-connection three-way valve, and are used for monitoring the pilot pressure, so as to control the oil supply channel of the main pump through the first oil supply port and the second oil supply port.

7. A control method for a hydraulic system of a bulldozer blade of an excavator according to any one of claims 1 to 6, characterized in that, The steps include: When the dozer blade is lowered: The main pump makes high-pressure oil flow through the right traveling valve through the second oil supply port, enters the fourth oil port of the dozer valve, flows out from the first oil port of the dozer valve, enters the first one-way balance valve of the two-way balance valve, and then enters the rodless cavity of the dozer oil cylinder to realize the lowering of the dozer blade, and the relief valve of the second one-way balance valve opens the reverse flow to return to the oil tank; When the dozer blade is lifted: The main pump makes high-pressure oil flow through the right traveling valve through the second oil supply port, enters the fourth oil port of the dozer valve, flows out from the second oil port of the dozer valve, enters the second one-way balance valve of the two-way balance valve, and then enters the rod cavity of the dozer oil cylinder to realize the lifting of the dozer blade, and the relief valve of the first one-way balance valve opens the reverse flow to return to the oil tank; When the dozer blade is lowered and straight traveling is combined: The main pump makes high-pressure oil enter the sixth oil port of the right traveling valve through the second oil supply port, then enter the working oil port of the right traveling motor through the second oil port of the right traveling valve; at the same time, the main pump makes high-pressure oil enter the third oil port of the straight traveling valve through the second oil supply port, then enter the seventh oil port of the left traveling valve through the second oil port of the straight traveling valve, and then enter the working oil port of the left traveling motor through the fourth oil port of the left traveling valve; The main pump makes high-pressure oil enter the fourth oil port of the dozer valve through the first oil supply port, then enter the fourth oil port of the dozer valve through the first oil port of the dozer valve, and then enter the first one-way balance valve of the two-way balance valve, and then enter the rodless cavity of the dozer oil cylinder to realize the lowering of the dozer blade, and the relief valve of the second one-way balance valve opens the reverse flow to return to the oil tank; When the dozer blade is lifted and straight traveling is combined: The main pump makes high-pressure oil enter the sixth oil port of the right traveling valve through the second oil supply port, then enter the working oil port of the right traveling motor through the second oil port of the right traveling valve; at the same time, the main pump makes high-pressure oil enter the third oil port of the straight traveling valve through the second oil supply port, then enter the seventh oil port of the left traveling valve through the second oil port of the straight traveling valve, and then enter the working oil port of the left traveling motor through the fourth oil port of the left traveling valve; The main pump enters the fourth oil port of the straight travel valve through the first oil port, and then enters the fourth oil port of the dozer valve through the first oil port of the straight travel valve, and then flows out from the second oil port of the dozer valve and enters the second one-way balance valve of the two-way balance valve, and then enters the rod cavity of the dozer oil cylinder to lift the dozer blade, and the overflow valve of the first one-way balance valve controlled by each other opens to return to the tank.

8. A control method of a hydraulic system of a bulldozer blade of an excavator according to claim 7, characterized in that, Before the main pump supplies oil, the spools of each valve are moved to the corresponding working position under the action of the pilot control oil; When the dozer blade is lowered: The spool of the first pilot oil port of the dozer valve moves to the right under the pressure of the pilot control oil; at the same time, the pilot control oil flows through the shuttle valve and the first one-way valve in turn to push the spool of the straight travel valve to move to the right; the spool of the first mid-cut valve moves to the left, and the spool of the second mid-cut valve moves to the right to realize mid-cut; When the dozer blade is lifted: The spool of the second pilot oil port of the dozer valve moves to the left under the pressure of the pilot control oil; at the same time, the pilot control oil flows through the shuttle valve and the first one-way valve in turn to push the spool of the straight travel valve to move to the right; the spool of the first mid-cut valve moves to the left, and the spool of the second mid-cut valve moves to the right to realize mid-cut; When the dozer blade is lowered and the straight travel is combined: The spool of the first pilot oil port of the dozer valve moves to the right under the pressure of the pilot control oil; at the same time, the pilot control oil flows through the shuttle valve and the first one-way valve in turn to push the spool of the straight travel valve to move to the right; the spool of the first mid-cut valve moves to the left, and the spool of the second mid-cut valve moves to the right to realize mid-cut; The spool of the second pilot oil port of the right travel valve moves to the left under the pressure of the pilot control oil, and at the same time, the spool of the first pilot oil port of the left travel valve moves to the right under the pressure of the pilot control oil; When the dozer blade is lifted and the straight travel is combined: The spool of the second pilot oil port of the dozer valve moves to the left under the pressure of the pilot control oil; at the same time, the pilot control oil flows through the shuttle valve and the first one-way valve in turn to push the spool of the straight travel valve to move to the right; the spool of the first mid-cut valve moves to the left, and the spool of the second mid-cut valve moves to the right to realize mid-cut; The spool of the second pilot oil port of the right travel valve moves to the left under the pressure of the pilot control oil, and at the same time, the spool of the first pilot oil port of the left travel valve moves to the right under the pressure of the pilot control oil.

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