An excavator hydraulic system and control method

Abstract

The application provides a hydraulic system and control method of excavator, which comprises a main pump, a main valve, a first hydraulic control reversing valve, a second hydraulic control reversing valve, a breaking hammer, a bulldozing oil cylinder and a bulldozing pilot handle. The first oil port of the first hydraulic control reversing valve is connected with the sixth oil port of the auxiliary valve connection of the main valve, the first oil port of the second hydraulic control reversing valve is connected with the fifth oil port of the auxiliary valve connection of the main valve, the first oil port of the breaking hammer is connected with the second oil port of the first hydraulic control reversing valve, and the second oil port of the breaking hammer is connected with the second oil port of the second hydraulic control reversing valve. The third oil port of the first hydraulic control reversing valve is connected with the rodless cavity of the bulldozing oil cylinder, and the third oil port of the second hydraulic control reversing valve is connected with the rod cavity of the bulldozing oil cylinder. The bulldozing pilot handle is connected with the two pilot oil ports of the auxiliary valve connection of the main valve through a shuttle valve, and is connected with the pilot oil ports of the two hydraulic control reversing valves respectively, so that the bulldozing oil cylinder performs a bulldozing action. The breaking control handle is connected with the first pilot oil port of the auxiliary valve connection of the main valve through a shuttle valve, so that the breaking hammer performs a breaking action. The application can realize the breaking and bulldozing functions simultaneously when the main valve has only an auxiliary valve connection.

Description

TECHNICAL FIELD

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

[0002] With the increasing richness of working conditions of the excavator, the breaking hammer and the bulldozing bucket become the auxiliary tools with higher frequency of use. In the normal case, the main valve in the standard configuration only has one auxiliary valve connection for the user to add one auxiliary tool. If two auxiliary tools need to be added, the structure of the main valve needs to be changed and the required auxiliary valve connection needs to be added. It is cumbersome to replace the main valve and other elements in the working site and the cost is high.

[0003] Therefore, there is an urgent need for a hydraulic system of an excavator and a control method, which can realize the breaking function and the bulldozing function at the same time when there is only one auxiliary valve connection in the main valve under the standard configuration of the hydraulic system. SUMMARY

[0004] The purpose of the present application is to provide a hydraulic system of an excavator and a control method, which aims to solve the technical problem of cumbersome modification and high cost of traditional hydraulic control when realizing the breaking function and the bulldozing function at the same time.

[0005] To achieve the above purpose, in a first aspect, the present application provides a hydraulic system of an excavator, comprising:

[0006] a main pump for providing high-pressure hydraulic oil;

[0007] a main valve comprising an auxiliary valve connection, the auxiliary valve connection being a pilot-operated hydraulic control valve having three working positions, and a first oil port of the auxiliary valve connection being connected with an oil outlet of the main pump;

[0008] a first hydraulic control reversing valve, a first oil port of the first hydraulic control reversing valve being connected with a sixth oil port of the auxiliary valve connection,

[0009] a second hydraulic control reversing valve, a first oil port of the second hydraulic control reversing valve being connected with a fifth oil port of the auxiliary valve connection,

[0010] a breaking hammer for performing a breaking action, a first oil port of the breaking hammer being connected with a second oil port of the first hydraulic control reversing valve, and a second oil port of the breaking hammer being connected with a second oil port of the second hydraulic control reversing valve;

[0011] a bulldozing oil cylinder for performing a bulldozing action, a third oil port of the first hydraulic control reversing valve being connected with a rodless chamber of the bulldozing oil cylinder, and a third oil port of the second hydraulic control reversing valve being connected with a rod chamber of the bulldozing oil cylinder;

[0012] The bulldozing pilot handle is connected with the first pilot port or the second pilot port of the auxiliary valve group through a shuttle valve, and is connected with the pilot ports of the first hydraulic control reversing valve and the second hydraulic control reversing valve, so as to push the spools to move to corresponding working positions to make the bulldozing cylinder execute a bulldozing action.

[0013] The crushing control handle is connected with the first pilot port of the auxiliary valve group through a shuttle valve, so as to push the spool of the auxiliary valve group to move to a corresponding working position to make the crushing hammer execute a crushing action.

[0014] As a further improvement of the above-mentioned scheme, the crushing control handle is connected with the first pilot port of the auxiliary valve group through a first shuttle valve;

[0015] A first proportional valve is further arranged between the crushing control handle and the first shuttle valve, the crushing control handle is communicatively connected with the first proportional valve, and is configured to control the reversing of the first proportional valve; a second oil port of the first proportional valve is connected with a pilot pump, a third oil port of the first proportional valve is connected with a second oil port of the first shuttle valve, a third oil port of the first shuttle valve is connected with the first pilot port of the auxiliary valve group, and a first oil port of the first shuttle valve is connected with a first oil port of the bulldozing pilot handle.

[0016] As a further improvement of the above-mentioned scheme, the bulldozing pilot handle is connected with the second pilot port of the auxiliary valve group through a second shuttle valve;

[0017] A second oil port of the bulldozing pilot handle is connected with a first oil port of the second shuttle valve, and a third oil port of the second shuttle valve is connected with the second pilot port of the auxiliary valve group.

[0018] A second oil port of the second shuttle valve is connected with a working oil port of a second proportional valve.

[0019] As a further improvement of the above-mentioned scheme, the bulldozing pilot handle is connected with the pilot ports of the first hydraulic control reversing valve and the second hydraulic control reversing valve through a third shuttle valve;

[0020] A second oil port of the bulldozing pilot handle is further connected with a first oil port of the third shuttle valve, and a third oil port of the third shuttle valve is connected with the pilot ports of the first hydraulic control reversing valve and the second hydraulic control reversing valve, respectively.

[0021] A second oil port of the third shuttle valve is connected with a first oil port of the first shuttle valve.

[0022] As a further improvement of the above-mentioned scheme, the auxiliary valve group is a three-position six-way pilot-operated hydraulic control reversing valve, and has a first working position, a neutral position and a second working position.

[0023] The second oil port of the auxiliary valve group is connected with the oil outlet of the main pump through a third one-way valve, and the third oil port of the auxiliary valve group is communicated with the oil tank;

[0024] In the middle position, the first oil port and the fourth oil port thereof are communicated, and the second oil port, the fifth oil port, the third oil port and the sixth oil port thereof are not communicated with each other;

[0025] In the first working position, the first oil port and the fourth oil port thereof are not communicated, the second oil port and the sixth oil port thereof are communicated, and the fifth oil port and the third oil port thereof are communicated;

[0026] In the second working position, the first oil port and the fourth oil port thereof are not communicated, the second oil port and the fifth oil port thereof are communicated, and the sixth oil port and the third oil port thereof are communicated.

[0027] As a further improvement of the above-mentioned scheme, the fifth oil port of the auxiliary valve group is further communicated with the oil tank through a first one-way overflow valve, and the sixth oil port of the auxiliary valve group is further communicated with the oil tank through a second one-way overflow valve.

[0028] As a further improvement of the above-mentioned scheme, the first hydraulic control reversing valve and the second hydraulic control reversing valve are both two-position three-way valves,

[0029] In the first working position, the first oil port and the second oil port thereof are communicated, and the third oil port thereof is not communicated with other oil ports;

[0030] In the second working position, the first oil port and the third oil port thereof are communicated, and the second oil port thereof is not communicated with other oil ports.

[0031] As a further improvement of the above-mentioned scheme, the excavator hydraulic system further comprises a bidirectional balance valve, and the bidirectional balance valve comprises a first one-way balance valve and a second one-way balance valve which are mutually pilot-controlled;

[0032] The third oil port of the first hydraulic control reversing valve is connected with the conductive end of the first one-way balance valve, and the end of the first one-way balance valve away from the conductive end is connected with the rodless chamber of the bulldozing oil cylinder; the third oil port of the second hydraulic control reversing valve is connected with the conductive end of the second one-way balance valve, and the end of the second one-way balance valve away from the conductive end is connected with the rod chamber of the bulldozing oil cylinder.

[0033] As a further improvement of the above-mentioned scheme, the first one-way balance valve comprises a first one-way valve and a first pilot overflow valve which are connected in parallel;

[0034] The second one-way balance valve comprises a second one-way valve and a second pilot overflow valve which are connected in parallel, and the first pilot overflow valve and the second pilot overflow valve are mutually staggered pilot-controlled.

[0035] In a second aspect, the present application also provides a control method of the excavator hydraulic system according to the first aspect, and the steps of the method comprise:

[0036] The crushing function: the first and second hydraulic control reversing valves are both in the first working position, the crushing control handle is controlled, the pilot oil enters the first pilot oil port of the auxiliary valve group through the first shuttle valve, so that the auxiliary valve group is in the second working position; the main pump supplies oil to the main valve, the high-pressure oil flows through the second and fifth oil ports of the auxiliary valve group, then flows into the first oil port of the second hydraulic control reversing valve, and then flows into the second hydraulic control reversing valve through the second oil port, so that the crushing hammer is crushed;

[0037] The bulldozing blade is lowered: the bulldozing pilot handle is pushed forward, the pilot oil flows into the pilot oil ports of the first and second hydraulic control reversing valves through the third shuttle valve, so that the two hydraulic control reversing valves are both in the second working position; meanwhile, the pilot oil also flows into the second pilot oil port of the auxiliary valve group through the second shuttle valve, so that the auxiliary valve group is in the first working position; the main pump supplies oil to the main valve, the high-pressure oil flows through the second and sixth oil ports of the auxiliary valve group, then flows into the first oil port of the first hydraulic control reversing valve, and then flows into the rodless cavity of the bulldozing cylinder through the third oil port, so that the bulldozing blade is lowered;

[0038] The bulldozing blade is lifted: the bulldozing pilot handle is pushed backward, the pilot oil flows into the pilot oil ports of the first and second hydraulic control reversing valves through the third shuttle valve, so that the two hydraulic control reversing valves are both in the second working position; meanwhile, the pilot oil also flows into the first pilot oil port of the auxiliary valve group through the first shuttle valve, so that the auxiliary valve group is in the second working position; the main pump supplies oil to the main valve, the high-pressure oil flows through the second and fifth oil ports of the auxiliary valve group, then flows into the first oil port of the second hydraulic control reversing valve, and then flows into the rod cavity of the bulldozing cylinder through the third oil port, so that the bulldozing blade is lifted.

[0039] As a further improvement of the above scheme, when the bulldozing blade is lowered: the high-pressure oil flows out of the third oil port of the first hydraulic control reversing valve, then enters the first one-way balance valve of the double-direction balance valve, and then enters the rodless cavity of the bulldozing cylinder, so that the bulldozing blade is lowered, and meanwhile, the overflow valve of the second one-way balance valve controlled by the pilot oil flows reversely to return to the oil tank;

[0040] When the bulldozing blade is lifted: the high-pressure oil flows out of the third oil port of the first hydraulic control reversing valve, then enters the second one-way balance valve of the double-direction balance valve, and then enters the rod cavity of the bulldozing cylinder, so that the bulldozing blade is lifted, and meanwhile, the overflow valve of the first one-way balance valve controlled by the pilot oil flows reversely to return to the oil tank.

[0041] Due to the above technical scheme, the present application has the following beneficial effects:

[0042] The hydraulic system of the excavator provided by the application, in the standard configuration of the negative flow hydraulic system, two hydraulic control reversing valves and shuttle valves are reasonably arranged,

[0043] The main valve is in the corresponding working position through the crushing control handle and the corresponding shuttle valve, and the first hydraulic control reversing valve and the second hydraulic control reversing valve are in the corresponding working position, so that the crushing function can be realized; the main valve is in the corresponding working position through the bulldozing pilot handle and the corresponding shuttle valve, and the first hydraulic control reversing valve and the second hydraulic control reversing valve are in the corresponding working position, so that the bulldozing function can be realized, so that the hydraulic system provided by the application can realize the crushing function and the bulldozing function at the same time when only one auxiliary valve group is connected in the main valve, and the structure is simple, the auxiliary connection does not need to be added on the main valve, and the cost is low. BRIEF DESCRIPTION OF DRAWINGS

[0044] 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 only constitute some embodiments of the application, and for those skilled in the art, other drawings can also be obtained according to the structures shown in these drawings without creative labor.

[0045] Figure 1 is a schematic view of the hydraulic system of the excavator disclosed by the application.

[0046] Reference signs:

[0047] 1, main pump; 2, main valve; 21, first one-way overflow valve; 22, second one-way overflow valve; 3, first hydraulic control reversing valve; 4, second hydraulic control reversing valve; 5, crushing hammer; 6, bulldozing oil cylinder; 7, crushing control handle; 71, first shuttle valve; 72, first proportional valve;

[0048] 8, bulldozing pilot handle; 81, second shuttle valve; 82, second proportional valve; 83, third shuttle valve;

[0049] 9, bidirectional balance valve; 91, first one-way balance valve; 92, second one-way balance valve.

[0050] The implementation, functional features and advantages of the application will be further described with reference to the embodiments and the accompanying drawings. DETAILED DESCRIPTION

[0051] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the 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 a person of ordinary skill in the art without creative effort belong to the scope of protection of the present application.

[0052] It should be noted that all directional indications (such as up, down, etc.) in the embodiments of the present application are only used to explain the relative position relationship, movement condition, etc. between components in a certain specific posture (as shown in the drawings), and if the specific posture changes, the directional indications also change accordingly.

[0053] 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 defined as "first", "second" can explicitly or implicitly include at least one of the features.

[0054] In addition, the technical solutions of the various embodiments of the present application can be combined with each other, but it must be based on the fact that a person of ordinary skill in the art can realize it, and when the combination of technical solutions contradicts each other or cannot be realized, 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.

[0055] Example 1

[0056] Referring to Figure 1 The present application provides a hydraulic system of excavator, comprising:

[0057] A main pump 1 is used to provide high-pressure hydraulic oil for the hydraulic system;

[0058] A main valve 2 comprises an auxiliary valve link, the auxiliary valve link is a pilot-operated hydraulic control valve, has three working positions, and a first oil port is connected with an oil outlet of the main pump 1. Specifically, a supply oil port P1 is arranged on a valve body of the main valve 2, the oil outlet of the main pump 1 is in communication with the supply oil port P1, the supply oil port P1 is in communication with a first oil port of the auxiliary valve link, and the supply oil port is also in communication with a second oil port of the auxiliary valve link through a one-way valve. The valve body of the main valve 2 is further provided with a pilot oil port pa2 and a pilot oil port pb2, the pilot oil port pa2 is in communication with a first pilot oil port of the auxiliary valve link, and the pilot oil port pb2 is in communication with a second pilot oil port of the auxiliary valve link. The valve body of the main valve 2 is further provided with an oil outlet A2 and an oil outlet B2, a fifth oil port of the auxiliary valve link is in communication with the oil outlet A2, and a sixth oil port of the auxiliary valve link is in communication with the oil outlet B2.

[0059] A first hydraulic control reversing valve 3, a first oil port of which is connected with a sixth oil port of the auxiliary valve group,

[0060] A second hydraulic control reversing valve 4, a first oil port of which is connected with a fifth oil port of the auxiliary valve group, the oil outlet B2 is further connected with the first oil port of the first hydraulic control reversing valve 3, and the oil outlet A2 is further connected with the first oil port of the second hydraulic control reversing valve 4; in the embodiment, the first hydraulic control reversing valve 3 and the second hydraulic control reversing valve 4 are both pilot type two-position three-way valves, in the first working position, the first oil port and the second oil port of the valve are communicated, and the third oil port is not communicated with other oil ports; in the second working position, the first oil port and the third oil port of the valve are communicated, and the second oil port is not communicated with other oil ports;

[0061] A breaking hammer 5 for performing a breaking action, a first oil port of which is connected with a second oil port of the first hydraulic control reversing valve 3, and a second oil port of which is connected with a second oil port of the second hydraulic control reversing valve 4;

[0062] A dozing oil cylinder 6 for performing a dozing action, a third oil port of the first hydraulic control reversing valve 3 is connected with a rodless cavity of the dozing oil cylinder 6, and a third oil port of the second hydraulic control reversing valve is connected with a rod cavity of the dozing oil cylinder 6;

[0063] A dozing pilot handle 8, which is connected with the first pilot oil port or the second pilot oil port of the auxiliary valve group and the pilot oil ports of the first hydraulic control reversing valve 3 and the second hydraulic control reversing valve through a shuttle valve, so as to push the valve core to move to the corresponding working position to make the dozing oil cylinder 6 perform a dozing action;

[0064] A breaking control handle 7, which is connected with the first pilot oil port of the auxiliary valve group through a shuttle valve, so as to push the valve core of the auxiliary valve group to move to the corresponding working position to make the breaking hammer 5 perform a breaking action;

[0065] In the present application, in the standard configuration of the negative flow hydraulic system, two hydraulic control reversing valves and a shuttle valve are reasonably arranged, without changing or modifying the structure of the main valve 2, the main valve 2 is made to be in the corresponding working position through the breaking control handle 7 and the corresponding shuttle valve, and the first hydraulic control reversing valve 3 and the second hydraulic control reversing valve 4 are both made to be in the corresponding working position, so as to realize the breaking function; the main valve 2 is also made to be in the corresponding working position through the dozing pilot handle 8 and the corresponding shuttle valve, and the first hydraulic control reversing valve 3 and the second hydraulic control reversing valve 4 are both made to be in the corresponding working position, so as to realize the dozing function, so that the hydraulic system provided by the present application can realize the breaking function and the dozing function at the same time when there is only one auxiliary valve group in the main valve 2, and the structure is simple, without the need to increase an auxiliary group on the main valve 2, and the cost is low.

[0066] As a preferred embodiment, the breaking control handle 7 is connected with the first pilot oil port of the auxiliary valve group through a first shuttle valve 71.

[0067] The first proportional valve 72 is connected between the crushing control handle 7 and the first shuttle valve 71, the crushing control handle 7 is in communication connection with the first proportional valve for controlling the reversing of the first proportional valve; the second oil port of the first proportional valve is connected with the pilot pump, the third oil port of the first proportional valve 72 is connected with the second oil port of the first shuttle valve 71, the third oil port of the first shuttle valve 71 is connected with the first pilot oil port of the auxiliary valve group; the first oil port of the first shuttle valve 71 is connected with the first oil port of the bulldozing pilot handle 8;

[0068] Specifically, the first proportional valve 72 is a two-position three-way pilot type electric control proportional valve, after controlling the first proportional valve 72, the first proportional valve 72 is electrified, and under the action of the pilot oil, the spool of the first proportional valve 72 moves to the left, the first oil port and the third oil port of the first proportional valve 72 are communicated, the pilot oil flows through the first shuttle valve 71 and then enters the first pilot oil port of the auxiliary valve group through the pilot oil port pa2, drives the spool to move to the left, so that the second working position is reached, so that the high-pressure oil supplied by the main pump 1 can be supplied to the breaking hammer 5 to realize the breaking action of the breaking hammer 5.

[0069] As a preferred embodiment, the bulldozing pilot handle 8 is connected with the second pilot oil port of the auxiliary valve group through the second shuttle valve 81;

[0070] The second oil port of the bulldozing pilot handle 8 is connected with the first oil port of the second shuttle valve 81, and the third oil port of the second shuttle valve 81 is connected with the second pilot oil port of the auxiliary valve group;

[0071] The second oil port of the second shuttle valve 81 is connected with the working oil port of the second proportional valve 82;

[0072] The bulldozing pilot handle 8 is connected with the pilot oil ports of the first hydraulic control reversing valve 3 and the second hydraulic control reversing valve 4 through the third shuttle valve 83;

[0073] The second oil port of the bulldozing pilot handle 8 is also connected with the first oil port of the third shuttle valve 83, and the third oil port of the third shuttle valve 83 is respectively connected with the pilot oil ports of the first hydraulic control reversing valve 3 and the second hydraulic control reversing valve 4;

[0074] The second oil port of the third shuttle valve 83 is connected with the first oil port of the first shuttle valve 71;

[0075] Specifically, pushing the bulldozing pilot handle 8 to move forward, one way of the pilot oil passes through the second shuttle valve 81 and then enters the second pilot oil port of the auxiliary valve group through the pilot oil port pb2, pushing the valve core of the auxiliary valve group to move right to make it in the first working position; another way of the pilot oil passes through the third shuttle valve 83 and then flows into the pilot oil ports of the first hydraulic control reversing valve 3 and the second hydraulic control reversing valve 4 respectively, and pushes the valve cores of the two hydraulic control reversing valves to move left to make them in the first working position, so that the high-pressure oil supplied by the main pump 1 can be supplied to the bulldozing oil cylinder 6 to realize the lowering and lifting actions of the bulldozing oil cylinder 6.

[0076] As a preferred embodiment, the auxiliary valve group is a three-position six-way pilot-operated hydraulic control reversing valve, which has a first working position, a neutral position and a second working position;

[0077] The second oil port of the auxiliary valve group is connected with the oil outlet of the main pump 1 through two series-connected third one-way valves, the third oil port of the auxiliary valve group is in communication with the oil tank, and the fourth oil port of the auxiliary valve group is in communication with the oil tank,

[0078] In the neutral position, the first oil port and the fourth oil port of the auxiliary valve group are in communication, and the second oil port, the fifth oil port, the third oil port and the sixth oil port of the auxiliary valve group are not in communication;

[0079] In the first working position, the first oil port and the fourth oil port of the auxiliary valve group are not in communication, the second oil port and the sixth oil port of the auxiliary valve group are in communication, and the fifth oil port and the third oil port of the auxiliary valve group are in communication;

[0080] In the second working position, the first oil port and the fourth oil port of the auxiliary valve group are not in communication, the second oil port and the fifth oil port of the auxiliary valve group are in communication, and the sixth oil port and the third oil port of the auxiliary valve group are in communication;

[0081] The fifth oil port of the auxiliary valve group is also in communication with the oil tank through the first one-way overflow valve 21, and the sixth oil port of the auxiliary valve group is also in communication with the oil tank through the second one-way overflow valve 22;

[0082] In this way, after the crushing control handle 7 is operated, the valve core of the auxiliary valve group moves left to make it in the second working position, the high-pressure oil pumped by the main pump 1 flows into the second oil port of the auxiliary valve group through the oil supply port P1 after passing through the two third one-way valves, then flows out through the fifth oil port of the auxiliary valve group, and then enters the first oil port of the first hydraulic control reversing valve 3 and flows out through the second oil port of the first hydraulic control reversing valve 3 to finally enter the second oil port of the crushing hammer 5 to perform the crushing action, while the low-pressure oil flows out from the first oil port of the crushing hammer 5, enters the second oil port of the second hydraulic control reversing valve 4, and then flows out through the first oil port of the second hydraulic control reversing valve 4 to return to the oil tank through the second one-way overflow valve 22.

[0083] As a preferred embodiment, the excavator hydraulic system further comprises a bidirectional balance valve 9, and the bidirectional balance valve 9 comprises a first one-way balance valve 91 and a second one-way balance valve 92 which are pilot-controlled with each other;

[0084] The third oil port of the first hydraulic control reversing valve 3 is connected with the conductive end of the first one-way balance valve 91, the end of the first one-way balance valve 91 far from the conductive end is connected with the rodless cavity of the dozer oil cylinder 6; the third oil port of the second hydraulic control reversing valve 4 is connected with the conductive end of the second one-way balance valve 92, the end of the second one-way balance valve 92 far from the conductive end is connected with the rod cavity of the dozer oil cylinder 6; specifically, the first one-way balance valve 91 comprises a first one-way valve and a first pilot relief valve connected in parallel;

[0085] The second one-way balance valve 92 comprises a second 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 staggered pilot control connection.

[0086] Embodiment 2

[0087] The application also provides a control method of the excavator hydraulic system as provided in Embodiment 1, and the steps thereof comprise:

[0088] The crushing function: the first hydraulic control reversing valve 3 and the second hydraulic control reversing valve 4 are both in the first working position, the crushing control handle 7 is controlled, the pilot oil enters the first pilot oil port of the auxiliary valve group after passing through the first shuttle valve 71, the valve core moves to the left, so that the auxiliary valve group is in the second working position (that is, the oil supply port P1 is communicated with the oil outlet A2 of the valve body of the main valve 2); the main pump 1 supplies oil to the oil supply port P1 of the main valve 2, the high-pressure oil flows through the second oil port and the fifth oil port of the auxiliary valve group, then flows into the first oil port of the second hydraulic control reversing valve 4, and then flows into the second oil port of the crushing hammer 5 through the second oil port to realize the crushing action, at the same time, the low-pressure oil flows out through the first oil port of the crushing hammer 5, then enters the second oil port of the first hydraulic control reversing valve 3, and then enters the oil outlet B2 of the main valve 2 through the first oil port, and returns to the oil tank through the second one-way relief valve 22 of the main valve 2 to realize the crushing function;

[0089] Pushing shovel down: pushing forward the pushing shovel pilot handle 8, the pilot oil flows into the pilot oil ports of the first and second hydraulic control reversing valves 3 and 4 through the third shuttle valve 83, the spools of the two hydraulic control reversing valves are both moved to the left, so that the two hydraulic control reversing valves are both in the second working position (i.e. the first and third oil ports of the two hydraulic control reversing valves are communicated) ; at the same time, the pilot oil also flows into the pilot oil port pb2 of the main valve 2 through the second shuttle valve 81, and then enters the second pilot oil port of the auxiliary valve group, the spool is moved to the right, so that the auxiliary valve group is in the first working position, the oil supply port P1 is communicated with the oil outlet B2 of the main valve 2; the main pump 1 supplies oil to the main valve 2, the high-pressure oil flows through the second and sixth oil ports of the auxiliary valve group, and then flows into the first oil port of the first hydraulic control reversing valve 3, and then flows into the rodless chamber of the pushing shovel oil cylinder 6 through the third oil port, the piston rod is extended, and the pushing shovel down action is realized, at the same time, the low-pressure oil enters the third oil port of the second hydraulic control reversing valve 4 through the rod chamber of the pushing shovel oil cylinder 6, and then flows out through the first oil port, and then enters the oil outlet A2 of the main valve 2, and then returns to the tank through the first one-way overflow valve 21 of the main valve 2;

[0090] Pushing shovel up: pushing backward the pushing shovel pilot handle 8, the pilot oil flows into the pilot oil ports of the first and second hydraulic control reversing valves 3 and 4 through the third shuttle valve 83, so that the two hydraulic control reversing valves are both in the second working position (i.e. the first and third oil ports of the two hydraulic control reversing valves are communicated) ; at the same time, the pilot oil also flows into the pilot oil port pa2 of the main valve 2 through the first shuttle valve 71, and then enters the first pilot oil port of the auxiliary valve group, the spool is moved to the left, so that the auxiliary valve group is in the second working position, the oil supply port P1 is communicated with the oil outlet A2 of the main valve 2; the main pump 1 supplies oil to the main valve 2, the high-pressure oil flows through the second and fifth oil ports of the auxiliary valve group, and then flows into the first oil port of the second hydraulic control reversing valve 4, and then flows into the rod chamber of the pushing shovel oil cylinder 6 through the third oil port, the piston rod is retracted, and the pushing shovel up action is realized, at the same time, the low-pressure oil enters the third oil port of the first hydraulic control reversing valve 3 through the rodless chamber of the pushing shovel oil cylinder 6, and then flows out through the first oil port, and then enters the oil outlet B2 of the main valve 2, and then returns to the tank through the second one-way overflow valve 22 of the main valve 2;

[0091] Such control method is simple to operate, only needs to control the crushing control handle 7 or the pushing shovel pilot handle 8, and the crushing function and the pushing shovel function can be realized at the same time when only one auxiliary valve group in the main valve 2.

[0092] As a preferred embodiment, when the bulldozing blade is lowered: high pressure oil flows out from the third oil port of the first hydraulic control reversing valve 3, enters the first one-way balance valve 91 of the double-way balance valve 9, and then enters the rodless cavity of the bulldozing oil cylinder 6 to realize the lowering of the bulldozing blade, while the overflow valve of the second one-way balance valve 92 controlled by each other opens the reverse flow and returns to the tank; specifically, the high pressure oil flowing into the oil port V1 of the double-way balance valve 9 passes through the first one-way valve and then flows into the rodless cavity of the bulldozing oil cylinder 6 from the oil port C1 of the double-way balance valve 9 to maintain the load and prevent reverse movement, the piston rod of the bulldozing oil cylinder 6 pushes out the bulldozing blade to lower, while when the second pilot overflow valve is applied with pilot pressure on the cross pilot oil path, the second pilot overflow valve opens to realize the reverse flow and return to the tank; in this way, the high pressure oil entering the rodless cavity serves as the pilot control oil of the second pilot overflow valve, and after the second pilot overflow valve is opened, the hydraulic oil can be slowly returned through the adjustment of the pilot pressure, so as to prevent the sudden drop of the bulldozing oil cylinder 6.

[0093] When the bulldozing blade is lifted: high pressure oil flows out from the third oil port of the first hydraulic control reversing valve 3, enters the second one-way balance valve 92 of the double-way balance valve 9, and then enters the rod cavity of the bulldozing oil cylinder 6 to realize the lifting of the bulldozing blade, while the overflow valve of the first one-way balance valve 91 controlled by each other opens the reverse flow and returns to the tank; specifically, the high pressure oil flowing into the oil port V2 of the double-way balance valve 9 passes through the second one-way valve and then flows into the rod cavity of the bulldozing oil cylinder 6 from the oil port C2 of the double-way balance valve 9 to maintain the load and prevent reverse movement, the piston rod of the bulldozing oil cylinder 6 retracts to lift the bulldozing blade, while when the first pilot overflow valve is applied with pilot pressure on the cross pilot oil path, the first pilot overflow valve opens to realize the reverse flow and return to the tank; in this way, the high pressure oil entering the rod cavity serves as the pilot control oil of the first pilot overflow valve, and after the first pilot overflow valve is opened, the hydraulic oil can be slowly returned through the adjustment of the pilot pressure, so as to prevent the sudden drop of the bulldozing oil cylinder 6.

[0094] The above is only a preferred embodiment of the present application, and does not limit the patent scope of the present application, and any equivalent structural transformation made under the inventive concept of the present application, or direct / indirect application in other related technical fields is included in the patent protection scope of the present application.

Claims

1. An excavator hydraulic system, characterized by, The utility model relates to a kind of hydraulic control system of bulldozer, including: Main pump for providing high-pressure hydraulic oil; Main valve, including auxiliary valve link, the auxiliary valve link is pilot operated hydraulic control valve, with three working positions, the first oil port is connected with the oil outlet of the main pump; First hydraulic control reversing valve, the first oil port is connected with the sixth oil port of the auxiliary valve link, Second hydraulic control reversing valve, the first oil port is connected with the fifth oil port of the auxiliary valve link, Break hammer, for performing breaking action, the first oil port is connected with the second oil port of the first hydraulic control reversing valve, the second oil port is connected with the second oil port of the second hydraulic control reversing valve; Bulldozing oil cylinder, for performing bulldozing action, the third oil port of the first hydraulic control reversing valve is connected with the rodless cavity of the bulldozing oil cylinder, the third oil port of the second hydraulic control reversing valve is connected with the rod cavity of the bulldozing oil cylinder; Bulldozing pilot handle, by shuttle valve with the first pilot oil port or the second pilot oil port of the auxiliary valve link, and with the pilot oil port of the first hydraulic control reversing valve and the second hydraulic control reversing valve connection, to push its valve core to move to corresponding working position make the bulldozing oil cylinder perform bulldozing action; Breaking control handle, by shuttle valve with the first pilot oil port of the auxiliary valve link, to push the auxiliary valve link valve core to move to corresponding working position make the break hammer perform breaking action; The auxiliary valve link is three-position six-way pilot operated hydraulic control reversing valve, with first working position, middle position and second working position; The second oil port of the auxiliary valve link is connected with the oil outlet of the main pump by third check valve, the third oil port of the auxiliary valve link is communicated with oil tank, the fourth oil port of the auxiliary valve link is communicated with oil tank, In middle position, its first oil port and its fourth oil port are communicated, its second oil port, its fifth oil port, its third oil port and its sixth oil port are not communicated with each other; In first working position, its first oil port and its fourth oil port are not communicated, its second oil port and its sixth oil port are communicated, its fifth oil port and its third oil port are communicated; In second working position, its first oil port and its fourth oil port are not communicated, its second oil port and its fifth oil port are communicated, its sixth oil port and its third oil port are communicated; The fifth oil port of the auxiliary valve link is also communicated with oil tank by first one-way overflow valve, the sixth oil port of the auxiliary valve link is also communicated with oil tank by second one-way overflow valve.

2. The hydraulic system of claim 1, wherein, The breaking control handle is connected with the first pilot oil port of the auxiliary valve link by first shuttle valve; The breaking control handle and the first shuttle valve are further provided with first proportional valve, the breaking control handle is connected with the first proportional valve communication, for controlling the reversing of the first proportional valve;The second oil port of the first proportional valve is connected with pilot pump, the third oil port of the first proportional valve is connected with the second oil port of the first shuttle valve, the third oil port of the first shuttle valve is connected with the first pilot oil port of the auxiliary valve link;The first oil port of the first shuttle valve is connected with the first oil port of the bulldozing pilot handle.

3. An excavator hydraulic system according to claim 2, wherein, The bulldozing pilot handle is connected with the second pilot oil port of the auxiliary valve link by second shuttle valve; The second oil port of the bulldozing pilot handle is connected with the first oil port of the second shuttle valve, the third oil port of the second shuttle valve is connected with the second pilot oil port of the auxiliary valve link; The second oil port of the second shuttle valve is connected with the working oil port of the second proportional valve.

4. An excavator hydraulic system according to claim 2 or 3, characterised in that, The bulldozing pilot handle is connected with the pilot oil ports of the first and second hydraulic control reversing valves through the third shuttle valve; The second oil port of the bulldozing pilot handle is also connected with the first oil port of the third shuttle valve, and the third oil port of the third shuttle valve is connected with the pilot oil ports of the first and second hydraulic control reversing valves respectively; The second oil port of the third shuttle valve is connected with the first oil port of the first shuttle valve.

5. An excavator hydraulic system according to any one of claims 1 to 3, wherein The first and second hydraulic control reversing valves are both two-position three-way valves, In the first working position, the first oil port and the second oil port are communicated, and the third oil port is not communicated with other oil ports; In the second working position, the first oil port and the third oil port are communicated, and the second oil port is not communicated with other oil ports.

6. An excavator hydraulic system according to any one of claims 1 to 3, wherein The excavator hydraulic system further comprises a bidirectional balance valve, which comprises a first one-way balance valve and a second one-way balance valve which are pilot-controlled with each other; The third oil port of the first hydraulic control reversing valve is connected with the conducting end of the first one-way balance valve, and the end of the first one-way balance valve away from the conducting end is connected with the rodless chamber of the bulldozing oil cylinder; the third oil port of the second hydraulic control reversing valve is connected with the conducting end of the second one-way balance valve, and the end of the second one-way balance valve away from the conducting end is connected with the rod chamber of the bulldozing oil cylinder.

7. An excavator hydraulic system according to claim 6, wherein, The first one-way balance valve comprises a first one-way valve and a first pilot relief valve connected in parallel; The second one-way balance valve comprises a second one-way valve and a second pilot relief valve connected in parallel, and the first and second pilot relief valves are connected in staggered pilot control with each other.

8. A control method for a hydraulic system of an excavator according to any one of claims 1 to 7, characterized in that, The steps include: Crushing function: the first and second hydraulic control reversing valves are both in the first working position, the crushing control handle is controlled, the crushing control handle is connected with the first pilot oil port of the auxiliary valve group through the first shuttle valve; the pilot oil enters the first pilot oil port of the auxiliary valve group through the first shuttle valve, so that the auxiliary valve group is in the second working position; the main pump supplies oil to the main valve, and the high-pressure oil flows through the second and fifth oil ports of the auxiliary valve group, then flows into the first oil port of the second hydraulic control reversing valve, and then flows into the crushing hammer through the second oil port to realize the crushing action; Bulldozing shovel down: the bulldozing pilot handle is pushed forward, the bulldozing pilot handle is connected with the second pilot oil port of the auxiliary valve group through the second shuttle valve; the bulldozing pilot handle is connected with the pilot oil ports of the first and second hydraulic control reversing valves through the third shuttle valve; the pilot oil flows into the pilot oil ports of the first and second hydraulic control reversing valves through the third shuttle valve, so that the two hydraulic control reversing valves are both in the second working position; at the same time, the pilot oil also enters the second pilot oil port of the auxiliary valve group through the second shuttle valve, so that the auxiliary valve group is in the first working position; the main pump supplies oil to the main valve, and the high-pressure oil flows through the second and sixth oil ports of the auxiliary valve group, then flows into the first oil port of the first hydraulic control reversing valve, and then flows into the rodless chamber of the bulldozing oil cylinder through the third oil port to realize the bulldozing shovel down action; Bulldozing blade lifting: pushing the bulldozing pilot handle backward, the pilot oil flows into the pilot oil ports of the first and second hydraulic control reversing valves through the third shuttle valve, so that the two hydraulic control reversing valves are both in the second working position; at the same time, the pilot oil also enters the first pilot oil port of the auxiliary valve group through the first shuttle valve, so that the auxiliary valve group is in the second working position; the main pump supplies oil to the main valve, the high-pressure oil flows through the second oil port and the fifth oil port of the auxiliary valve group, then flows into the first oil port of the second hydraulic control reversing valve, and finally flows into the rod cavity of the bulldozing oil cylinder through the third oil port of the second hydraulic control reversing valve, so as to realize the bulldozing blade lifting action.

Images