WO2023071417A1 - 一种带有推土铲浮动功能的推土液压系统以及挖掘机 - Google Patents

一种带有推土铲浮动功能的推土液压系统以及挖掘机 Download PDF

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WO2023071417A1
WO2023071417A1 PCT/CN2022/112360 CN2022112360W WO2023071417A1 WO 2023071417 A1 WO2023071417 A1 WO 2023071417A1 CN 2022112360 W CN2022112360 W CN 2022112360W WO 2023071417 A1 WO2023071417 A1 WO 2023071417A1
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WIPO (PCT)
Prior art keywords
port
bulldozing
valve
bulldozer
oil
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PCT/CN2022/112360
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English (en)
French (fr)
Inventor
李金澎
宋之克
刘跃吉
马立国
张飞
王荣标
岳苏华
尚福利
潘赛赛
王海成
赵鹏坤
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徐州徐工挖掘机械有限公司
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Priority to AU2022374838A priority Critical patent/AU2022374838A1/en
Publication of WO2023071417A1 publication Critical patent/WO2023071417A1/zh

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    • E—FIXED CONSTRUCTIONS
    • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02F—DREDGING; SOIL-SHIFTING
    • E02F3/00—Dredgers; Soil-shifting machines
    • E02F3/04—Dredgers; Soil-shifting machines mechanically-driven
    • E02F3/76—Graders, bulldozers, or the like with scraper plates or ploughshare-like elements; Levelling scarifying devices
    • E02F3/80—Component parts
    • E02F3/84—Drives or control devices therefor, e.g. hydraulic drive systems
    • E—FIXED CONSTRUCTIONS
    • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02F—DREDGING; SOIL-SHIFTING
    • E02F3/00—Dredgers; Soil-shifting machines
    • E02F3/04—Dredgers; Soil-shifting machines mechanically-driven
    • E02F3/76—Graders, bulldozers, or the like with scraper plates or ploughshare-like elements; Levelling scarifying devices
    • E02F3/80—Component parts
    • E02F3/84—Drives or control devices therefor, e.g. hydraulic drive systems
    • E02F3/844—Drives or control devices therefor, e.g. hydraulic drive systems for positioning the blade, e.g. hydraulically
    • E—FIXED CONSTRUCTIONS
    • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02F—DREDGING; SOIL-SHIFTING
    • E02F3/00—Dredgers; Soil-shifting machines
    • E02F3/04—Dredgers; Soil-shifting machines mechanically-driven
    • E02F3/76—Graders, bulldozers, or the like with scraper plates or ploughshare-like elements; Levelling scarifying devices
    • E02F3/80—Component parts
    • E02F3/84—Drives or control devices therefor, e.g. hydraulic drive systems
    • E02F3/844—Drives or control devices therefor, e.g. hydraulic drive systems for positioning the blade, e.g. hydraulically
    • E02F3/847—Drives or control devices therefor, e.g. hydraulic drive systems for positioning the blade, e.g. hydraulically using electromagnetic, optical or acoustic beams to determine the blade position, e.g. laser beams
    • E—FIXED CONSTRUCTIONS
    • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02F—DREDGING; SOIL-SHIFTING
    • E02F9/00—Component parts of dredgers or soil-shifting machines, not restricted to one of the kinds covered by groups E02F3/00 - E02F7/00
    • E02F9/20—Drives; Control devices
    • E02F9/22—Hydraulic or pneumatic drives
    • E02F9/2264—Arrangements or adaptations of elements for hydraulic drives
    • E—FIXED CONSTRUCTIONS
    • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02F—DREDGING; SOIL-SHIFTING
    • E02F9/00—Component parts of dredgers or soil-shifting machines, not restricted to one of the kinds covered by groups E02F3/00 - E02F7/00
    • E02F9/20—Drives; Control devices
    • E02F9/22—Hydraulic or pneumatic drives
    • E02F9/2264—Arrangements or adaptations of elements for hydraulic drives
    • E02F9/2267—Valves or distributors

Definitions

  • the invention relates to the technical field of engineering machinery hydraulics, in particular to a bulldozer hydraulic system with a bulldozer blade floating function and an excavator.
  • the object of the present invention is to provide a bulldozer hydraulic system and an excavator with a bulldozing blade floating function, so as to solve the problem that the existing excavator bulldozing blade does not have the floating function.
  • the present invention adopts following technical scheme for realizing above-mentioned purpose of the invention:
  • the invention provides a bulldozer hydraulic system with a bulldozer floating function, which includes a load sensitive pump, a bulldozer cylinder, a load sensitive valve and a position switching mechanism;
  • the load sensing valve includes a four-position reversing valve
  • the four-position reversing valve has at least a switchable first station, a second station and a third station;
  • the P port of the load sensing pump is connected with the A port of the bulldozer cylinder
  • the B port of the bulldozer cylinder is connected with the oil tank
  • the pusher The small cavity A port of the soil shovel oil cylinder enters oil, and the large cavity B port returns oil to control the bulldozing blade to rise;
  • the P port of the load sensing pump is connected with the B port of the bulldozer cylinder
  • the A port of the bulldozer cylinder is connected with the oil tank
  • the pusher The soil shovel oil cylinder enters the oil from the B port of the large chamber, and returns the oil from the A port of the small chamber to control the descent of the bulldozer;
  • the A port and the B port of the bulldozing shovel oil cylinder communicate with the T port of the load sensing valve, and the small cavity A port and the large cavity B of the bulldozing shovel oil cylinder
  • the port is connected with the oil tank to realize the floating function of the bulldozing blade
  • the station switching mechanism is configured to switch and select the station of the four-position reversing valve according to load pressure feedback or handle signal output.
  • the station switching mechanism includes a bulldozing pilot valve, and port 1 and port 2 of the bulldozing pilot valve are in communication with port a and port b of the four-position reversing valve, respectively;
  • the pilot oil enters port b through the port 1 of the bulldozing pilot valve to push the spool of the four-position reversing valve to move to the left, and the four-position reversing valve The position reversing valve is in the second position.
  • the large chamber of the bulldozing shovel oil cylinder enters oil, and the small chamber returns oil to control the bulldozing shovel to descend;
  • Pilot oil enters port a through port 2 of the bulldozing pilot valve to push the spool of the four-position reversing valve to move to the right.
  • the cavity enters the oil, and the large cavity returns the oil to control the rising of the bulldozing blade;
  • the bulldozing pilot valve When the control pilot pressure is in the second stage and is greater than the limit positioning setting value, the bulldozing pilot valve enters the limit positioning, and the pilot oil enters port b through port 1 of the bulldozer pilot valve to push the four-position reversing valve The spool moves to the left, and the four-position reversing valve is in the third station. At this time, the small chamber A port and the large chamber B port of the bulldozing blade oil cylinder are connected with the oil tank to realize the floating function of the bulldozing blade.
  • the bulldozing hydraulic system also includes a pilot pressure feedback pipeline and a load pressure feedback pipeline;
  • the pilot pressure feedback line and the load pressure feedback line are connected to the pressure feedback PL port of the load sensing pump through a shuttle valve; the LS port of the shuttle valve and the load sensing valve are respectively connected to the load pressure feedback port
  • the pipeline is connected;
  • Port b of the shuttle valve and the four-position reversing valve are respectively connected to the pilot pressure feedback pipeline, and port T of the load sensing valve is connected to the oil tank;
  • the load pressure PLS is greater than the pilot pressure Pbls, and the LS port of the load pressure feedback pipeline is connected to the PL port of the load sensing pump to ensure normal operation.
  • the load pressure feedback of the condition can control the pressure and flow output of the load sensitive pump;
  • the pilot pressure Pbls is greater than the load pressure PLS
  • the bls port of the pilot pressure feedback pipeline is connected to the PL port of the load sensing pump
  • the output pressure of the load sensing pump is controlled to be greater than the Pilot pressure when the four-position reversing valve is in the third position, so that the four-position reversing valve is always in the third position, keeping the small chamber A port and the large chamber B port of the bulldozer cylinder connected to the fuel tank To realize the floating function of bulldozing blade.
  • the large chamber B port of the bulldozer cylinder communicates with the B1 port of the load sensing valve
  • the small chamber A port of the bulldozer cylinder communicates with the A1 port of the load sensing valve
  • the load Port P of the sensitive pump communicates with port P1 of the load sensing valve.
  • the station switching mechanism includes an electronically controlled bulldozing handle, a controller, a first pilot solenoid valve and a second pilot solenoid valve, and the controller judges the current Then, by controlling the first pilot solenoid valve and the second pilot solenoid valve to push the four-position reversing valve to switch positions, so as to realize the rising, falling and floating of the bulldozing blade.
  • first pilot solenoid valve and the second pilot solenoid valve are respectively connected to port a and port b of the four-position reversing valve;
  • the controller When the electronically controlled bulldozing handle is in the neutral position, the controller has no output, and the four-position reversing valve is in the neutral position;
  • the controller controls the opening of the first pilot solenoid valve to push the first station of the four-position reversing valve to conduct, and the B port of the bulldozing shovel oil cylinder It is connected with the fuel tank, at this moment, the small cavity of the bulldozing blade oil cylinder enters oil, the large cavity returns oil, and the bulldozing blade rises;
  • the controller controls the opening of the second pilot solenoid valve to push the second station of the four-position reversing valve to conduct , the A port of the bulldozing blade oil cylinder communicates with the oil tank, at this moment, the bulldozer blade oil cylinder is fed with oil, the small chamber returns oil, and the bulldozer blade descends;
  • the controller controls the opening of the second pilot solenoid valve to push the third station of the four-position reversing valve to conduct, and at this time the bulldozing shovel oil cylinder
  • the A port of the small cavity, the B port of the large cavity and the fuel tank are in the conduction state, and the floating function of the bulldozing blade is turned on.
  • the present invention provides an excavator, which includes an excavator body and the bulldozer hydraulic system with the floating function of the bulldozer blade as described above, and the bulldozer hydraulic system is arranged on the excavator body.
  • the invention solves the problem that the bulldozing blade of the existing excavator does not have a floating function; at the same time, the method of integrating the reversing valve is adopted, and there is no need to connect a high-voltage electromagnetic reversing valve hydraulic component between the reversing valve and the cylinder of the bulldozing shovel.
  • the integrated way saves space and reduces costs.
  • Fig. 1 is a hydraulic schematic diagram 1 of a bulldozer hydraulic system with a bulldozer blade floating function provided according to an embodiment of the present invention
  • Fig. 2 is a pressure-stroke control curve diagram of the port b of the four-position reversing valve in the bulldozer hydraulic system with the bulldozer floating function provided according to an embodiment of the present invention
  • Fig. 3 is a curve diagram of the pressure at port 1 of the bulldozing pilot valve in the bulldozing hydraulic system with the floating function of the bulldozing blade provided according to an embodiment of the present invention - the stroke control curve of the ejector rod;
  • Fig. 4 is a second hydraulic schematic diagram of a bulldozer hydraulic system with a bulldozer blade floating function provided according to an embodiment of the present invention.
  • the present invention provides a bulldozer hydraulic system with a bulldozer floating function, including a load sensitive pump 1, a load sensitive valve 2, a bulldozer cylinder 3, a bulldozer pilot valve 8 and a feedback Pipeline
  • load sensing valve 2 includes four-position reversing valve 23
  • load sensing pump 1 includes plunger pump and load feedback adjustment device
  • bulldozer cylinder 3 includes oil cylinder large cavity and oil cylinder Small cavity
  • bulldozer pilot valve 8 includes unilateral limit positioning
  • feedback pipeline includes shuttle valve 6, load pressure feedback pipeline 5 and pilot pressure feedback pipeline 4, bulldozing shovel oil cylinder large chamber B port and load sensing valve B1 port Connected, bulldozer shovel oil cylinder small chamber A port is connected with load sensing valve A1 port
  • load sensing pump P port is connected with load sensing valve P1 port
  • shuttle valve 6 is connected with load sensing pump pressure feedback port PL
  • load pressure feedback pipeline 5 are respectively connected with the shuttle valve 6
  • the bulldozer cylinder 3 has a small chamber The oil enters and the large cavity returns the oil. If the four-position reversing valve 23 is in the right position, that is, the P port of the load sensing pump is connected to the B port of the bulldozer cylinder 3, and the A port of the bulldozer cylinder 3 is connected to the oil tank 7. At this time, the bulldozer cylinder 3 is large. The cavity enters the oil, and the small cavity returns the oil.
  • the four-position reversing valve 23 is in the right two positions, that is, the ports A and B of the bulldozing shovel oil cylinder 3 are connected to the T port of the load sensing valve.
  • the shovel float function is turned on, increasing the excavator's productivity when filling trenches and grading sites.
  • the above-mentioned bulldozing pilot valve 8 is a hydraulic control pilot valve, and has a single-side limit positioning function, which can realize limit pressure locking control.
  • the above-mentioned four-position reversing valve 23 is controlled by the pilot pressure output of the dozing pilot valve to realize the reversing of the reversing valve.
  • the bulldozing hydraulic system in the present invention includes a load sensitive pump 1, a bulldozing shovel oil cylinder 3, and a four-position reversing valve 23.
  • the load sensitive pump 1 outputs high-pressure oil according to the load pressure feedback, and the four-position reversing valve 23 communicates with the The small chamber A port of the bulldozer cylinder 3 or the large chamber B port are connected, and the rising, falling and floating of the bulldozing blade are further controlled by controlling the direction change of the four-position reversing valve 23 .
  • a bulldozing pilot valve 8 is also included.
  • the corresponding relationship between the control pressure at port 1 of the bulldozing pilot valve and the stroke of the ejector rod is shown in Figure 3.
  • the control pilot pressure is 0-25bar; when the stroke of the ejector rod is greater than 6mm, it enters the limit positioning, and the control pilot pressure is greater than 25bar.
  • the pilot oil enters port b through port 1 of the pilot valve to push the spool to move to the left, and the four-position reversing valve 23 is in the right position.
  • the bulldozer pilot valve 8 enters the limit position, the pilot oil enters the b port through the pilot valve 1 port to push the valve core to move to the left, and the four-position reversing valve 23 is in the right two position.
  • the A port and the B port of the bulldozer cylinder 3 are connected with the T port of the fuel tank to realize the floating function of the bulldozer blade.
  • the above hydraulic system also includes a pilot pressure feedback pipeline 4 and a load pressure feedback pipeline 5, the pilot pressure feedback pipeline 4 and the load pressure feedback pipeline 5 communicate with the pressure feedback PL of the load sensing pump 1 through the shuttle valve 6 The mouth is connected.
  • the load pressure PLS is greater than the pilot pressure Pbls, and the LS port of the load pressure feedback pipeline 5 is connected to the PL port of the load sensing pump 1 to ensure normal working conditions.
  • Load pressure feedback to control the pressure and flow output of the load sensing pump 1.
  • the pilot pressure Pbls is greater than the load pressure PLS
  • the bls port of the pilot pressure feedback pipeline 4 is connected to the PL port of the load sensing pump 1
  • the output pressure of the load sensing pump 1 is controlled to be greater than the four-position switch
  • the pilot pressure when the directional valve 23 is in the second right position keeps the four-position reversing valve 23 in the second right position all the time, ensuring that the A port and B port of the bulldozing blade cylinder 3 are connected with the T port of the oil tank, and the bulldozing blade is always floating Function.
  • the pilot hydraulic control part of the present invention can also be realized by electric control, select the electric control bulldozing handle 12, and the controller 11 judges the current handle state according to the signal output by the electric control bulldozer handle 12, and then through the control
  • the first pilot solenoid valve 9 and the second pilot solenoid valve 10 push the four-position reversing valve 23 to move, thereby realizing the rising, falling and floating of the bulldozing blade.
  • the controller 11 When the electronically controlled bulldozing handle 12 is in the neutral position, the controller 11 has no output, and the four-position reversing valve 23 is in the neutral position;
  • the controller 11 controls the first pilot solenoid valve 9 to open, and pushes the four-position reversing valve 23 to conduct at the left position.
  • the B port of the soil shovel oil cylinder is connected with the oil tank. At this time, the small cavity of the bulldozer shovel oil cylinder enters oil, the large cavity returns oil, and the bulldozer shovel rises;
  • the controller 12 controls the opening of the second pilot solenoid valve 10, and pushes the right one of the four-position reversing valve 23 to conduct, that is, the pump P
  • the port is connected to the B port of the bulldozer cylinder, and the A port of the bulldozer cylinder is connected to the oil tank. At this time, the bulldozer cylinder is filled with oil, and the small cavity is returned, and the bulldozer is lowered.
  • the controller 12 controls the opening degree of the second pilot solenoid valve 10, and pushes the right two-position of the four-position reversing valve 23 to conduct, that is, the A port and the B port of the bulldozing shovel oil cylinder are connected to each other.
  • the T port is connected.
  • the signal collected by the controller for the state (up, down, and suspension) of the electronically controlled bulldozing handle 12 is not limited to the commonly used PWM signal, and it is sufficient to accurately identify the current working state required by the bulldozing handle.
  • the controller 11 controls the second pilot solenoid valve 10, it can control the conduction position of the four-position reversing valve 23 to be the first right or the second right by controlling its opening. Refer to Figure 2 for the stroke control curve of pressure at port b.

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  • Engineering & Computer Science (AREA)
  • Mining & Mineral Resources (AREA)
  • Civil Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Structural Engineering (AREA)
  • Mechanical Engineering (AREA)
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Abstract

一种带有推土铲浮动功能的推土液压系统以及挖掘机，包括负载敏感泵（1）、推土铲油缸（3）、负载敏感阀（2）和工位切换机构；负载敏感阀（2）包括四位换向阀（23）；四位换向阀（23）在第一工位时，推土铲油缸（3）小腔A口进油，大腔B口回油，控制推土铲上升；四位换向阀（23）在第二工位时，推土铲油缸（3）大腔B口进油，小腔A口回油，控制推土铲下降；四位换向阀（23）在第三工位时，推土铲油缸（3）的小腔A口、大腔B口与油箱（7）相连通，实现推土铲浮动功能。设置有上述推土液压系统的挖掘机解决了现有挖掘机推土铲不具备浮动功能的问题，同时采用换向阀集成的方式，无需在换向阀和推土铲油缸之间外接高压电磁换向阀液压元件，而采用元件集成的方式，能节省空间和成本降低。

Description

一种带有推土铲浮动功能的推土液压系统以及挖掘机 技术领域
本发明涉及工程机械液压技术领域，尤其涉及一种带有推土铲浮动功能的推土液压系统以及挖掘机。
背景技术
随着挖掘机液压系统不断升级迭代，液压系统的设计越来越追求创新性和多样化。对于一些挖掘机，为了实现快速推铲平地作业，还装有推土铲。目前市场上的挖掘机推土铲都是通过推土铲油缸的伸缩控制上升与下降，在该系推土液压系统中的推土铲不具有浮动功能，在沟渠回填和场地平整作业时效率较低。
发明内容
本发明的目的是提供一种带有推土铲浮动功能的推土液压系统以及挖掘机，解决现有挖掘机推土铲不具备浮动功能的问题。
本发明的上述技术目的是通过以下技术方案得以实现的：
本发明为实现上述发明目的采用如下技术方案：
本发明提供了一种带有推土铲浮动功能的推土液压系统，包括负载敏感泵、推土铲油缸、负载敏感阀和工位切换机构；
所述负载敏感阀包括四位换向阀；
所述四位换向阀至少具有能够切换的第一工位、第二工位和第三工位；
所述四位换向阀在第一工位时，所述负载敏感泵的P口与所述推土铲油缸的A口连通，所述推土铲油缸的B口与油箱连通，所述推土铲油缸小腔A口进油，大腔B口回油，控制推土铲上升；
所述四位换向阀在第二工位时，所述负载敏感泵的P口与所述推土铲油缸的B口连通，所述推土铲油缸的A口与油箱连通，所述推土铲油缸大腔B口进油，小腔A口回油，控制推土铲下降；
所述四位换向阀在第三工位时，所述推土铲油缸的A口、B口与负载敏感阀的T口连通，所述推土铲油缸的小腔A口、大腔B口与油箱相连通，实现推土铲浮动功能；
所述工位切换机构被配置为根据负载压力反馈或手柄信号输出对所述四位换向阀的工位进行切换选择。
进一步地，所述工位切换机构包括推土先导阀，所述推土先导阀的1口和2口分别与所述四位换向阀的a口和b口对应相导通；
当控制先导压力处于第一阶段0-极限定位设定值时，先导油通过所述推土先导阀的1口进入b口推动所述四位换向阀的阀芯向左移动，所述四位换向阀处于第二工位，此时推土铲油缸大腔进油，小腔回油，控制推土铲下降；
先导油通过所述推土先导阀的2口进入a口推动所述四位换向阀的阀芯向右移动，所述四位换向阀处于第一工位，此时推土铲油缸小腔进油，大腔回油，控制推土铲上升；
当控制先导压力处于第二阶段大于极限定位设定值时，所述推土先导阀进入极限定位，先导油通过所述推土先导阀的1口进入b口推动所述四位换向阀的阀芯向左移动，所述四位换向阀处于第三工位，此时推土铲油缸的小腔A口、大腔B口与油箱相连通，实现推土铲浮动功能。
进一步地，所述推土液压系统还包括先导压力反馈管路和负载压力反馈管路；
所述先导压力反馈管路和负载压力反馈管路通过梭阀与所述负载敏感泵的压力反馈PL口相连通；所述梭阀和所述负载敏感阀的LS口分别与所述负载压力反馈管路相连通；
所述梭阀和所述四位换向阀的b口分别与所述先导压力反馈管路相连通，所述负载敏感阀的T口连通油箱；
当挖掘机在使用浮动功能进行沟渠回填和场地平整作业时，负载压力PLS大于先导压力Pbls，所述负载压力反馈管路的LS口与所述负载敏感泵的PL口相导通，保证正常工况的负载压力反馈，控制负载敏感泵的压力和流量输出；
当挖掘机处于怠速工况时，先导压力Pbls大于负载压力PLS，所述先导压力反馈管路的bls口与负载敏感泵的PL口相导通，控制所述负载敏感泵的输出压力大于所述四位换向阀处于第三工位时的先导压力，使所述四位换向阀始终处于第三工位，保持所述推土铲油缸的小腔A口、大腔B口与油箱相连通，实现推土铲浮动功能。
进一步地，所述推土铲油缸的大腔B口与所述负载敏感阀的B1口连通，所述推土铲油缸的小腔A口与所述负载敏感阀的A1口连通，所述负载敏感泵的P口与所述负载敏感阀的P1口连通。
进一步地，所述工位切换机构包括电控推土手柄、控制器、第一先导电磁阀和第二先导电磁阀，所述控制器根据所述电控推土手柄输出的信号，来判断当前的手柄状态，然后通过控制第一先导电磁阀和第二先导电磁阀来推动所述四位换向阀切换工位，从而实现推土铲的上升、下降及浮动。
进一步地，所述第一先导电磁阀和第二先导电磁阀分别与所述四位换向阀的a口和b口对应相导通；
所述电控推土手柄处于中位时，所述控制器无输出，所述四位换向阀处于中位；
所述电控推土手柄输出a口控制信号时，所述控制器控制第一先导电磁阀开启，推动所述四位换向阀第一工位导通，所述推土铲油缸的B口与油箱连通，此时所述推土铲油缸小腔进油，大腔回油，推土铲上升；
所述电控推土手柄输出b口控制信号且未输出推土悬浮信号时，所述控制器控制所述第二先导电磁阀开度，推动所述四位换向阀第二工位导通，所述推土铲油缸的A口与油箱连通，此时推土铲油缸大腔进油，小腔回油，推土铲下降；
所述电控推土手柄输出推土悬浮信号时，所述控制器控制所述第二先导电磁阀开度，推动所述四位换向阀第三工位导通，此时推土铲油缸的小腔A口、大腔B口与油箱处于导通状态，推土铲浮动功能打开。
本发明提供了一种挖掘机，包括挖掘机本体和如上述的带有推土铲浮动功能的推土液压系统，所述推土液压系统设于所述挖掘机本体上。
本发明的有益效果：
本发明解决现有挖掘机推土铲不具备浮动功能的问题；同时采用换向阀集成的方式，无需在换向阀和推土铲油缸之间外接高压电磁换向阀液压元件，因采用元件集成的方式，节省空间，成本降低。
附图说明
图1为根据本发明实施例提供的带有推土铲浮动功能的推土液压系统的液压原理图一；
图2为根据本发明实施例提供的带有推土铲浮动功能的推土液压系统中四位换向阀b口压力—行程控制曲线图；
图3为根据本发明实施例提供的带有推土铲浮动功能的推土液压系统中推土先导阀1口压力—顶杆行程控制曲线图；
图4为根据本发明实施例提供的带有推土铲浮动功能的推土液压系统的液压原理图二。
具体实施方式
下面结合附图对本发明的技术方案做进一步的详细说明：
参照图1-图3，本发明提供了一种带有推土铲浮动功能的推土液压系统，包括负载敏感泵1、负载敏感阀2、推土铲油缸3、推土先导阀8和反馈管路，负载敏感阀2包括四位换向阀23、压力补偿阀22和卸荷阀21，负载敏感泵1包括柱塞泵和负载反馈调节装置，推土铲油缸3包括油缸大腔和油缸小腔，推土先导阀8包括单侧极限定位，反馈管路包括梭阀6、负载压力反馈管路5和先导压力反馈管路4，推土铲油缸大腔B口与负载敏感阀B1口连通，推土铲油缸小腔A口与负载敏感阀A1口连通，负载敏感泵P口与负载敏感阀P1口连通，梭阀6与负载敏感泵压力反馈口PL相连通，负载压力反馈管路5分别与梭阀6和负载敏感阀LS口相连通，先导压力反馈管路4分别与梭阀6和四位换向阀先导口b相连通，推土先导阀1口和2口分别与四位换向阀a口和b口相导通，负载敏感阀T口与油箱7相连通。若四位换向阀23处于左位，即负载敏感泵P口与推土铲油缸3的A口连通，推土铲油缸3的B口与油箱7连通，此时推土铲油缸3小腔进油，大腔回油。若四位换向阀23处于右一位，即负载敏感泵P口与推土铲油缸3的B口连通，推土铲油缸3的A口与油箱7连通，此时推土铲油缸3大腔进油，小腔回油。若四位换向阀23处于右二位，即推土铲油缸3的A口、B口与负载敏感阀T口连通，此时推土铲油缸3大小腔与油箱处于导通状态，推土铲浮动功能打开，从而提高挖掘机在沟渠回填和场地平整作业时的工作效率。
上述推土先导阀8为液控先导阀，并且带有单侧极限定位功能，可以实现极限压力锁紧控制。
上述四位换向阀23为推土先导阀输出的先导压力控制，实现换向阀的换向。
本发明中的推土液压系统，包括负载敏感泵1、推土铲油缸3、四位换向阀23，负载敏感泵1根据负载压力反馈输出高压油液，经四位换向阀23分别与推土铲油缸3小腔A口或大腔B口相连通，通过控制四位换向阀23换向，进一步的控制推土铲的上升、下降和浮动。
在上述液压系统中，所述四位换向阀23的先导压力与阀芯行程对应关系如图2所示，当先导压力为第一阶段0-25bar时，控制阀芯处于左位或右一位，实现推土铲的上升或下降，当先导压力为第二阶段大于25bar时，控制阀芯处于右二位，实现推土铲的浮动。
在上述液压系统中，还包括推土先导阀8，所述推土先导阀1口控制压力与顶杆行程对应关系如图3所示，当推土先导阀顶杆行程处于0-6mm时，控制先导压力为0-25bar；当顶杆行程大于6mm时，进入极限定位，控制先导压力大于25bar。当控制先导压力处于第一阶段0-25bar时，先导油通过先导阀1口进入b口推动阀芯向左移动，四位换向阀23处于右一位，此时推土铲油缸3大腔进油，小腔回油；先导油通过先导阀2口进入a口推动阀芯向右移动，四位换向阀23处于左位，此时推土铲油缸3小腔进油，大腔回油。当控制先导压力处于第二阶段大于25bar时，推土先导阀8进入极限定位，先导油通过先导阀1口进入b口推动阀芯向左移动，四位换向阀23处于右二位，此时推土铲油缸3的A口、B口与油箱T口相连通，实现推土铲浮动功能。
在上述液压系统中，还包括先导压力反馈管路4和负载压力反馈管路5，所述先导压力反馈管路4和负载压力反馈管路5通过梭阀6与负载敏感泵1的压力反馈PL口相连通。当挖掘机在使用浮动功能进行沟渠回填和场地平整作业时，负载压力PLS大于先导压力Pbls，负载压力反馈管路5的LS口与负载敏感泵1的PL口相导通，保证正常工况的负载压力反馈，控制负载敏感泵1的压力和流量输出。当挖掘机处于怠速工况时，先导压力Pbls大于负载压力PLS，先导压力反馈管路4的bls口与负载敏感泵1的PL口相导通，控制负载敏感泵1的输出压力大于四位换向阀23处于右二位时的先导压力，使四位换向阀23始终处于右二位，保证推土铲油缸3的A口、B口与油箱T口相连通，一直实现推土铲浮动功能。
参照图4，本发明的先导液控部分还可以通过电控实现，选用电控推土手柄12，控制器11根据电控推土手柄12输出的信号，来判断当前的手柄状态，然后通过控制第一先导电磁阀9和第二先导电磁阀10来推动四位换向阀23移动，从而实现推土铲的上升、下降及浮动。
电控推土手柄12处于中位时，控制器11无输出，四位换向阀23处于中位；
电控推土手柄12输出a口控制信号时，控制器11控制第一先导电磁阀9开启，推动四位换向阀23左位导通，泵P口与推土铲油缸A口连通，推土铲油缸B口与油箱连通，此时推土铲油缸小腔进油，大腔回油，推土铲上升；
电控推土手柄12输出b口控制信号,且未输出推土悬浮信号时，控制器12控制第二先导电磁阀10开度，推动四位换向阀23右一位导通，即泵P口与推土铲油缸B口连通，推土铲油缸A口与油箱 连通，此时推土铲油缸大腔进油，小腔回油，推土铲下降。
电控推土手柄12输出推土悬浮信号时，控制器12控制第二先导电磁阀10开度，推动四位换向阀23右二位导通，即推土铲油缸A口、B口与T口连通，此时推土铲油缸大小腔与油箱处于导通状态，推土铲浮动功能打开。
本发明中控制器采集电控推土手柄12状态(上升、下降、悬浮)的信号不限于常用的PWM信号，能准确识别出当前推土手柄要求的工作状态即可。控制器11控制第二先导电磁阀10时，可通过控制其开度大小来，控制推动四位换向阀23的导通位为右一或者右二。b口压力的行程控制曲线可参考图2。
以上对本发明的较佳实施进行了具体说明，当然，本发明还可以采用与上述实施方式不同的形式，熟悉本领域的技术人员在不违背本发明精神的前提下所作的等同的变换或相应的改动，都应该属于本发明的保护范围内。

Claims (7)

  1. 一种带有推土铲浮动功能的推土液压系统，其特征在于，包括负载敏感泵、推土铲油缸、负载敏感阀和工位切换机构；
    所述负载敏感阀包括四位换向阀；
    所述四位换向阀至少具有能够切换的第一工位、第二工位和第三工位；
    所述四位换向阀在第一工位时，所述负载敏感泵的P口与所述推土铲油缸的A口连通，所述推土铲油缸的B口与油箱连通，所述推土铲油缸小腔A口进油，大腔B口回油，控制推土铲上升；
    所述四位换向阀在第二工位时，所述负载敏感泵的P口与所述推土铲油缸的B口连通，所述推土铲油缸的A口与油箱连通，所述推土铲油缸大腔B口进油，小腔A口回油，控制推土铲下降；
    所述四位换向阀在第三工位时，所述推土铲油缸的A口、B口与负载敏感阀的T口连通，所述推土铲油缸的小腔A口、大腔B口与油箱相连通，实现推土铲浮动功能；
    所述工位切换机构被配置为根据负载压力反馈或手柄信号输出对所述四位换向阀的工位进行切换选择。
  2. 根据权利要求1所述的一种带有推土铲浮动功能的推土液压系统，其特征在于，所述工位切换机构包括推土先导阀，所述推土先导阀的1口和2口分别与所述四位换向阀的a口和b口对应相导通；
    当控制先导压力处于第一阶段0-极限定位设定值时，先导油通过所述推土先导阀的1口进入b口推动所述四位换向阀的阀芯向左移动，所述四位换向阀处于第二工位，此时推土铲油缸大腔进油，小腔回油，控制推土铲下降；
    先导油通过所述推土先导阀的2口进入a口推动所述四位换向阀的阀芯向右移动，所述四位换向阀处于第一工位，此时推土铲油缸小腔进油，大腔回油，控制推土铲上升；
    当控制先导压力处于第二阶段大于极限定位设定值时，所述推土先导阀进入极限定位，先导油通过所述推土先导阀的1口进入b口推动所述四位换向阀的阀芯向左移动，所述四位换向阀处于第三工位，此时推土铲油缸的小腔A口、大腔B口与油箱相连通，实现推土铲浮动功能。
  3. 根据权利要求1所述的一种带有推土铲浮动功能的推土液压系统，其特征在于，所述推土液压系统还包括先导压力反馈管路和负载压力反馈管路；
    所述先导压力反馈管路和负载压力反馈管路通过梭阀与所述负载敏感泵的压力反馈PL口相连通；
    所述梭阀和所述负载敏感阀的LS口分别与所述负载压力反馈管路相连通；
    所述梭阀和所述四位换向阀的b口分别与所述先导压力反馈管路相连通，所述负载敏感阀的T口连通油箱；
    当挖掘机在使用浮动功能进行沟渠回填和场地平整作业时，负载压力PLS大于先导压力Pbls，所述负载压力反馈管路的LS口与所述负载敏感泵的PL口相导通，保证正常工况的负载压力反馈，控制负载敏感泵的压力和流量输出；
    当挖掘机处于怠速工况时，先导压力Pbls大于负载压力PLS，所述先导压力反馈管路的bls口与负载敏感泵的PL口相导通，控制所述负载敏感泵的输出压力大于所述四位换向阀处于第三工位时的先导压力，使所述四位换向阀始终处于第三工位，保持所述推土铲油缸的小腔A口、大腔B口与油箱相连通，实现推土铲浮动功能。
  4. 根据权利要求1所述的一种带有推土铲浮动功能的推土液压系统，其特征在于，所述推土铲油缸的大腔B口与所述负载敏感阀的B1口连通，所述推土铲油缸的小腔A口与所述负载敏感阀的A1口连通，所述负载敏感泵的P口与所述负载敏感阀的P1口连通。
  5. 根据权利要求1所述的一种带有推土铲浮动功能的推土液压系统，其特征在于，所述工位切换机构包括电控推土手柄、控制器、第一先导电磁阀和第二先导电磁阀，所述控制器根据所述电控推土手柄输出的信号，来判断当前的手柄状态，然后通过控制第一先导电磁阀和第二先导电磁阀来推动所述四位换向阀切换工位，从而实现推土铲的上升、下降及浮动。
  6. 根据权利要求5所述的一种带有推土铲浮动功能的推土液压系统，其特征在于，所述第一先导电磁阀和第二先导电磁阀分别与所述四位换向阀的a口和b口对应相导通；
    所述电控推土手柄处于中位时，所述控制器无输出，所述四位换向阀处于中位；
    所述电控推土手柄输出a口控制信号时，所述控制器控制第一先导电磁阀开启，推动所述四位换向阀第一工位导通，所述推土铲油缸的B口与油箱连通，此时所述推土铲油缸小腔进油，大腔回油，推土铲上升；
    所述电控推土手柄输出b口控制信号且未输出推土悬浮信号时，所述控制器控制所述第二先导电磁阀开度，推动所述四位换向阀第二工位导通，所述推土铲油缸的A口与油箱连通，此时推土铲油缸大腔进油，小腔回油，推土铲下降；
    所述电控推土手柄输出推土悬浮信号时，所述控制器控制所述第二先导电磁阀开度，推动所述四位换向阀第三工位导通，此时推土铲油缸的小腔A口、大腔B口与油箱处于导通状态，推土铲浮动功能打开。
  7. 一种挖掘机，其特征在于，包括挖掘机本体和如权利要求1至6中任一项所述的带有推土铲浮动功能的推土液压系统，所述推土液压系统设于所述挖掘机本体上。
PCT/CN2022/112360 2021-10-29 2022-08-15 一种带有推土铲浮动功能的推土液压系统以及挖掘机 WO2023071417A1 (zh)

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CN113882444B (zh) * 2021-10-29 2023-03-14 徐州徐工挖掘机械有限公司 一种带有推土铲浮动功能的推土液压系统以及挖掘机
CN115233767B (zh) * 2022-08-25 2023-12-05 徐州徐工挖掘机械有限公司 一种浮动平衡液压系统及挖掘机
CN115748855B (zh) * 2022-12-16 2023-06-30 徐州徐工挖掘机械有限公司 一种挖掘机动臂浮动液压控制系统及控制方法

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