Load-sensitive hydraulic system and excavator

Abstract

The invention discloses a load-sensitive hydraulic system and an excavator, and the load-sensitive hydraulic system comprises an oil supply module, a pilot control module, a load-sensitive valve group and target action equipment, the load-sensitive valve group controls the high-pressure pump hydraulic oil and the main pump hydraulic oil to converge on an oil supply channel of a target walking motor according to an independent target walking signal, or controls the high-pressure pump hydraulic oil and the main pump hydraulic oil to converge on an oil supply channel of a target accessory according to an independent target accessory signal; or according to the target walking signal and the target accessory signal, controlling the high-pressure pump hydraulic oil and the main pump hydraulic oil to converge to the oil supply channel of the target accessory. According to the load-sensitive hydraulic system, it can be ensured that the torque of the engine is fully absorbed, so that the oil consumption efficiency is improved, meanwhile, flow supplement is provided for the corresponding accessories and / or walking motors when actions of the accessories and / or the walking motors are executed, and therefore the working efficiency of the accessories and the working efficiency of the walking motors are improved.

Description

Technical Field

[0001] This invention relates to the field of hydraulic control technology, and in particular to a load-sensitive hydraulic system and an excavator. Background Technology

[0002] Currently, the load-sensitive system of excavators is an energy-saving hydraulic circuit with the core concept of "supplying flow and pressure on demand". It typically uses a load-sensitive pump and a load-sensitive multi-way valve group to achieve independent and interference-free speed regulation of multiple actuators, thereby significantly reducing throttling and overflow losses.

[0003] However, in practical applications, the mechanical power valve of the load-sensitive pump in the load-sensitive system cannot fully absorb engine torque, resulting in low fuel efficiency. Simultaneously, when the load-sensitive system performs combined attachment and travel actions, insufficient flow supply to the attachment and travel motors leads to low work efficiency.

[0004] Therefore, how to improve the system's fuel efficiency and enhance the working efficiency of attachments and travel motors has become an urgent problem to be solved. Summary of the Invention

[0005] This invention discloses a load-sensitive hydraulic system and an excavator that can ensure full absorption of engine torque to improve fuel efficiency. At the same time, when executing attachment and / or travel motor actions, it provides flow supplement to the corresponding attachment and / or travel motor to improve the working efficiency of the attachment and travel motor.

[0006] To achieve the above objectives, in a first aspect, the present invention discloses a load-sensitive hydraulic system, the system comprising: The oil supply module is used to supply hydraulic oil to the main pump and hydraulic oil to the high-pressure pump. A pilot control module is connected to the oil supply module via an oil circuit. The pilot control module is used to provide target travel signals and target attachment signals. A load-sensitive valve assembly, which is connected to the oil supply module and the pilot control module oil circuit respectively; The target motion device includes: a target walking motor, a target attachment, and a target composite motion device, wherein the target attachment, the target walking motor, and the target composite motion device are all connected to the oil circuit of the load-sensitive valve group; The load-sensitive valve group is used to deliver the main pump hydraulic oil to the target composite motion device. The load-sensitive valve group is also used to control the merging of the high-pressure pump hydraulic oil and the main pump hydraulic oil supply channels to the target travel motor based on a separate target travel signal. Furthermore, the load-sensitive valve group is used to control the merging of the high-pressure pump hydraulic oil and the main pump hydraulic oil supply channels to the target attachment based on a separate target attachment signal. Finally, the load-sensitive valve group is used to control the merging of the high-pressure pump hydraulic oil and the main pump hydraulic oil supply channels to the target attachment based on both the target travel signal and the target attachment signal.

[0007] As an optional implementation, in an embodiment of the first aspect of the present invention, the pilot control module includes: A pilot oil source valve assembly, wherein the oil inlet end of the pilot oil source valve assembly is connected to the oil circuit of the oil supply module; The travel pilot valve group is connected to the travel pilot oil source, the pilot oil source valve group and the load sensitive valve group respectively. The travel pilot valve group is used to output the target travel signal to the load sensitive valve group according to the main pump hydraulic oil and the travel pilot oil source. The attachment pilot valve group is connected to the oil circuits of the attachment pilot oil source, the pilot oil source valve group and the load-sensitive valve group respectively. The attachment pilot valve group is used to output the target attachment signal to the load-sensitive valve group according to the hydraulic oil of the main pump and the attachment pilot oil source.

[0008] As an optional implementation, in an embodiment of the first aspect of the present invention, the load-sensitive valve assembly includes: A switching valve, wherein the first end of the switching valve is connected to the oil circuit of the oil supply module, the first pressure receiving end of the switching valve is connected to the oil circuit of the travel pilot valve group, and the second pressure receiving end of the switching valve is connected to the oil circuit of the attachment pilot valve group. The travel control valve assembly has its inlet end connected to the oil supply module and the second end oil circuit of the switching valve, respectively, and its outlet end connected to the oil circuit of the target travel motor. The attachment control valve assembly has its inlet end connected to the oil supply module and the third oil circuit of the switching valve, respectively, and its outlet end connected to the target attachment oil circuit. The switching valve is used to switch the oil passage between the first and second ends of the switching valve to be open according to the target travel signal, the switching valve is used to switch the oil passage between the first and third ends of the switching valve to be open according to the target attachment signal, and the switching valve is used to switch the oil passage between the first and third ends of the switching valve to be open according to the target travel signal and the target attachment signal.

[0009] As an optional implementation, in an embodiment of the first aspect of the present invention, the walking pilot valve assembly includes: The first shuttle valve is connected to the oil circuits of the first travel pilot oil source and the second travel pilot oil source respectively. The first shuttle valve is used to generate a first travel pilot signal based on the first travel pilot oil source and the second travel pilot oil source. The second shuttle valve is connected to the oil circuits of the third travel pilot oil source and the fourth travel pilot oil source respectively. The second shuttle valve is used to generate a second travel pilot signal according to the third travel pilot oil source and the fourth travel pilot oil source. The third shuttle valve is connected to the first pressure receiving end of the switching valve, the first shuttle valve, and the second shuttle valve oil circuit. The second shuttle valve is used to generate the target travel signal based on the first travel pilot signal and the second travel pilot signal source.

[0010] As an optional implementation, in an embodiment of the first aspect of the invention, the accessory pilot valve assembly includes: The fourth shuttle valve is connected to the second pressure receiving end of the switching valve, the first attachment pilot oil source, and the second attachment pilot oil source oil circuit. The fourth shuttle valve is used to generate the target attachment signal based on the first attachment pilot oil source and the second attachment pilot oil source.

[0011] As an optional implementation, in an embodiment of the first aspect of the present invention, the oil supply module includes: A hydraulic oil tank, which is used to store initial hydraulic oil; A load-sensitive main pump is connected to the hydraulic oil tank, the travel control valve group, and the attachment control valve group respectively. The load-sensitive main pump is used to pump the initial hydraulic oil as the main pump hydraulic oil to the travel control valve group and the attachment control valve group. A high-pressure gear pump is connected to the hydraulic oil tank and the first end oil circuit of the switching valve, respectively. The high-pressure gear pump is used to pump the initial hydraulic oil as the high-pressure pump hydraulic oil to the switching valve.

[0012] As an optional implementation, in an embodiment of the first aspect of the present invention, the walking control valve assembly further includes: The travel main control valve is connected to the oil inlet of the load-sensitive main pump. The travel pressure compensation valve has its inlet end connected to the connecting outlet end of the travel main control valve and the second end oil circuit of the switching valve, its outlet end connected to the first working end oil circuit of the travel main control valve, and its second working end connected to the target travel motor oil circuit.

[0013] As an optional implementation, in an embodiment of the first aspect of the present invention, the attachment control valve assembly further includes: The accessory main control valve is connected to the oil inlet of the load-sensitive main pump. The attachment pressure compensation valve has its inlet end connected to the oil circuit of the connecting outlet end of the attachment main control valve. The third end of the switching valve and the oil outlet end of the travel pressure compensation valve are both connected to the oil circuit of the first working end of the attachment main control valve. The second working end of the attachment main control valve is connected to the oil circuit of the target attachment.

[0014] As an optional implementation, in an embodiment of the first aspect of the present invention, the oil supply module further includes: The main pump control unit is connected to the control terminal of the load-sensitive main pump, the travel control valve group, and the attachment control valve group respectively. The main pump control unit is used to limit the maximum displacement of the load-sensitive main pump according to the system hydraulic pressure.

[0015] Secondly, the present invention discloses an excavator, characterized in that the excavator comprises: Excavator body; The load-sensitive hydraulic system as described in the first aspect of the present invention is installed in the excavator body.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows: The load-sensitive hydraulic system provided by this invention controls the oil supply status of the main pump hydraulic oil and the high-pressure pump hydraulic oil to the target travel motor, target attachments, and other complex actions through a load-sensitive valve group. When performing complex actions that do not involve attachments and travel, the main pump hydraulic oil is used solely as the main oil source for the system. In this case, the oil supply module can absorb all the engine torque to supply oil for the corresponding complex action, thereby improving fuel efficiency. Simultaneously, when performing complex actions involving attachments and / or travel, the high-pressure pump hydraulic oil and the main pump hydraulic oil are combined to jointly supply oil to the corresponding attachments and travel motors, achieving flow supplementation for the attachments and travel motors, thereby improving their working efficiency.

[0017] The excavator provided by this invention employs the aforementioned load-sensitive hydraulic system. Through a load-sensitive valve group, it controls the oil supply status of the main pump hydraulic oil and the high-pressure pump hydraulic oil to the target travel motor, target attachments, and other complex actions. When performing complex actions not involving attachments and travel, the main pump hydraulic oil serves as the primary oil source for the system. In this case, the oil supply module can absorb all engine torque to supply oil for the corresponding complex action, thereby improving fuel efficiency. Simultaneously, when performing complex actions involving attachments and / or travel, the high-pressure pump hydraulic oil and the main pump hydraulic oil are combined to jointly supply oil to the corresponding attachments and travel motor, achieving flow supplementation for the attachments and travel motor, thereby improving their working efficiency. Attached Figure Description

[0018] Figure 1 This is a block diagram of one embodiment of the load-sensitive hydraulic system of the present invention; Figure 2 This is a schematic diagram of the structure of one embodiment of the load-sensitive hydraulic system of the present invention; Figure 3 This is a schematic diagram of a specific embodiment of the load-sensitive valve group in the load-sensitive hydraulic system of the present invention.

[0019] The meanings of the reference numerals in the attached figures are as follows: Oil supply module 100, hydraulic oil tank 110, load-sensitive main pump 120, high-pressure gear pump 130, LS valve 141, electronically controlled displacement regulator 142, pressure sensor 143, angle sensor 144, pilot control module 200, pilot oil source valve group 210, travel pilot valve group 220, first shuttle valve 221, second shuttle valve 222, third shuttle valve 223, attachment pilot valve group 230, fourth shuttle valve 231, load-sensitive valve group 300, switching valve 310, travel control valve group 320, travel main control valve 321, travel pressure compensation valve 322, attachment control valve group 330, attachment main control valve 331, attachment pressure compensation valve 332, compound motion control valve group 340, target motion device 400, target travel motor 410, target attachment 420, target compound motion device 430. Detailed Implementation

[0020] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] In this invention, the terms "upper," "lower," "left," "right," "front," "rear," "top," "bottom," "inner," "outer," "middle," "vertical," "horizontal," "lateral," and "longitudinal" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. These terms are primarily for the purpose of better describing the invention and its embodiments, and are not intended to limit the indicated devices, elements, or components to having a specific orientation, or to be constructed and operated in a specific orientation.

[0022] Furthermore, in addition to indicating direction or positional relationship, some of the aforementioned terms may also have other meanings. For example, the term "above" may also be used in certain situations to indicate a dependency or connection. Those skilled in the art can understand the specific meaning of these terms in this invention based on the specific circumstances.

[0023] Furthermore, the terms "installation," "setup," "equipped with," "connection," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral structure; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium, or an internal connection between two devices, components, or parts. Those skilled in the art can understand the specific meaning of these terms in this invention based on the specific circumstances.

[0024] Furthermore, the terms "first," "second," etc., are primarily used to distinguish different devices, components, or parts (which may be the same or different in specific type and construction), and are not intended to indicate or imply the relative importance or quantity of the indicated devices, components, or parts. Unless otherwise stated, "a plurality of" means two or more.

[0025] The technical solution of the present invention will be further described below with reference to the embodiments and accompanying drawings.

[0026] Currently, the load-sensitive system of construction machinery such as excavators is an energy-saving hydraulic circuit with the core concept of "supplying flow and pressure on demand". It typically uses a load-sensitive pump and a load-sensitive multi-way valve group to achieve independent and interference-free speed regulation of multiple actuators, thereby significantly reducing throttling and overflow losses.

[0027] However, in practical applications, the mechanical power valve of the load-sensitive pump in the load-sensitive system cannot fully absorb the engine torque, resulting in low fuel efficiency. Simultaneously, when a single-pump load-sensitive system performs combined attachment and travel actions, insufficient flow supply to the attachment and travel motors leads to low work efficiency.

[0028] Therefore, how to improve the system's fuel efficiency and enhance the working efficiency of attachments and travel motors has become an urgent problem to be solved.

[0029] In this regard, embodiments of the present invention provide a load-sensitive hydraulic system and an excavator that can ensure full absorption of engine torque, thereby improving fuel efficiency. At the same time, when executing attachment and / or travel motor actions, it provides flow supplement to the corresponding attachment and / or travel motor, thereby improving the working efficiency of the attachment and travel motor.

[0030] like Figure 1 and Figure 2As shown, this invention discloses a load-sensitive hydraulic system, which includes: an oil supply module 100, a pilot control module 200, a load-sensitive valve group 300, and a target motion device 400. The oil supply module 100 provides hydraulic oil to the main pump and hydraulic oil to the high-pressure pump; the pilot control module 200 is connected to the oil supply module 100 via an oil circuit, and provides target travel signals and target attachment signals; the load-sensitive valve group 300 is connected to the oil supply module 100 and the pilot control module 200 via oil circuits respectively; the target motion device 400 includes: a target travel motor 410, a target attachment 420, and a target composite motion device 430, all of which are connected to the load-sensitive valve group 300 via an oil circuit; the load-sensitive valve group 300... Group 300 is used to deliver the main pump hydraulic oil to the target compound motion device 430. The load-sensitive valve group 300 is used to control the merging of the high-pressure pump hydraulic oil and the main pump hydraulic oil supply channels to the target travel motor 410 according to the individual target travel signal. The load-sensitive valve group 300 is used to control the merging of the high-pressure pump hydraulic oil and the main pump hydraulic oil supply channels to the target attachment 420 according to the individual target attachment signal. The load-sensitive valve group 300 is used to control the merging of the high-pressure pump hydraulic oil and the main pump hydraulic oil supply channels to the target attachment 420 according to the target travel signal and the target attachment signal.

[0031] In this embodiment, a load-sensitive hydraulic system is applied to construction machinery, including excavators. The following embodiment uses an excavator as an example. This construction machinery can be configured with target motion devices 400 as needed. The target motion devices 400 include: a target travel motor 410, a target attachment 420, and a target composite motion device 430. Specifically, the target travel motor 410 includes hydraulic motors for left and right travel, and the target composite motion device 430 includes devices such as a boom, stick, bucket, bulldozer blade, boom swing cylinder, and swing motor that perform composite motions.

[0032] The oil supply module 100 pumps main pump hydraulic oil and high-pressure pump hydraulic oil to the load-sensitive valve assembly 300, and also pumps main pump hydraulic oil to the pilot control module 200. The main pump hydraulic oil is pumped by the load-sensitive main pump 120 in the oil supply module 100, and the high-pressure pump hydraulic oil is pumped by the high-pressure gear pump 130 in the oil supply module 100. The operator can input travel pilot signals or attachment pilot signals to the pilot control module 200 via the pilot control lever or pedal in the cab of the construction machinery. The pilot control module 200 then combines this with the main pump hydraulic oil input to generate corresponding target travel signals or target attachment signals. It is understood that the signals described above and below all represent hydraulic oil pressure signals.

[0033] When performing compound actions that do not involve attachments and travel, the operator does not need to input pilot signals for attachments and travel. That is, the pilot control module 200 will not output target travel signals or target attachment signals. At this time, the load-sensitive valve group 300 connects the oil supply module 100 with the corresponding target compound action device 430, and at the same time returns the high-pressure pump hydraulic oil to the oil supply module 100. That is, the main pump hydraulic oil is used as the main oil supply source for the compound action. The load-sensitive main pump 120 in the oil supply module 100 can absorb all the torque of the construction machinery engine to supply oil for the corresponding compound action, while the high-pressure gear pump 130 does not occupy the engine torque, thereby improving the system's fuel efficiency.

[0034] When performing actions that do not involve attachments but involve walking, the operator only inputs a walking pilot signal. That is, the pilot control module 200 outputs a target walking signal to the load-sensitive valve group 300. At this time, the load-sensitive valve group 300 combines the hydraulic oil of the high-pressure pump with the hydraulic oil of the main pump according to the target walking signal, and opens the oil supply channel to the target walking motor 410, thereby increasing the flow rate and execution speed of the walking action.

[0035] When performing actions that do not involve walking but involve attachments, the operator only inputs the attachment pilot signal. That is, the pilot control module 200 outputs the target attachment signal to the load-sensitive valve group 300. At this time, the load-sensitive valve group 300 combines the high-pressure pump hydraulic oil with the main pump hydraulic oil according to the target attachment signal, and opens the oil supply channel to the target attachment 420, thereby increasing the flow rate and execution speed of the attachment action.

[0036] When performing actions involving both walking and attachments, the operator inputs a walking pilot signal and an attachment pilot signal. That is, the pilot control module 200 outputs a target walking signal and a target attachment signal to the load-sensitive valve group 300. At this time, the load-sensitive valve group 300 combines the high-pressure pump hydraulic oil with the main pump hydraulic oil according to the target walking signal and the target attachment signal, and opens the oil supply channel to the target attachment 420, thereby increasing the flow rate and execution speed of the attachment action.

[0037] As can be seen, the load-sensitive hydraulic system of the present invention can control the oil supply status of the main pump hydraulic oil and the high-pressure pump hydraulic oil to the target travel motor 410, the target attachment 420, and other compound actions through the load-sensitive valve group 300. When performing compound actions that do not involve attachments and travel, the main pump hydraulic oil is used as the main oil source of the system. At this time, the oil supply module 100 can absorb all the engine torque to supply oil for the corresponding compound action, thereby improving fuel efficiency. At the same time, when performing compound actions involving attachments and / or travel, the high-pressure pump hydraulic oil and the main pump hydraulic oil are combined to supply oil to the corresponding attachments and travel motors, thereby supplementing the flow of the attachments and travel motors and improving their working efficiency.

[0038] like Figure 2 As shown, in an optional embodiment, the pilot control module 200 includes: a pilot oil source valve group 210, a travel pilot valve group 220, and an attachment pilot valve group 230. The oil inlet of the pilot oil source valve group 210 is connected to the oil circuit of the oil supply module 100; the travel pilot valve group 220 is connected to the oil circuits of the travel pilot oil source, the pilot oil source valve group 210, and the load-sensitive valve group 300, respectively, and is used to output the target travel signal to the load-sensitive valve group 300 based on the main pump hydraulic oil and the travel pilot oil source; the attachment pilot valve group 230 is connected to the oil circuits of the attachment pilot oil source, the pilot oil source valve group 210, and the load-sensitive valve group 300, respectively, and is used to output the target attachment signal to the load-sensitive valve group 300 based on the main pump hydraulic oil and the attachment pilot oil source.

[0039] In this optional embodiment, the oil supply module 100 is connected to the pilot oil source valve group 210 via an oil circuit. The pilot oil source valve group 210 is connected to the travel pilot valve group 220 and the attachment pilot valve group 230 via oil circuits. Both the travel pilot valve group 220 and the attachment pilot valve group 230 are connected to the load-sensitive valve group 300 via an oil circuit. The travel pilot valve group 220 is connected to an external travel pilot oil source circuit, and the attachment pilot valve group 230 is connected to an external attachment pilot oil source circuit. The operator can control the on / off state of the pilot oil source valve group 210 through the control panel or other equipment in the cab of the construction machinery, thereby controlling the supply of hydraulic oil from the main pump to the travel pilot valve group 220 and the attachment pilot valve group 230. The operator can also control the output of corresponding pilot signals from the travel pilot oil source and the attachment pilot oil source through the pilot control lever or control pedal in the cab of the construction machinery.

[0040] When a walking action is required, the operator controls the walking pilot oil source to output a walking pilot signal to the walking pilot valve assembly 220. The walking pilot valve assembly 220 integrates the walking pilot signal to form a target walking signal before sending it to the load-sensitive valve assembly 300. When an attachment action is required, the operator controls the attachment pilot oil source to output an attachment pilot signal to the attachment pilot valve assembly 230. The attachment pilot valve assembly 230 integrates the attachment pilot signal to form a target attachment signal before sending it to the load-sensitive valve assembly 300.

[0041] like Figure 2 and Figure 3 As shown, in an optional embodiment, the load-sensitive valve assembly 300 includes: a switching valve 310, a travel control valve assembly 320, and an attachment control valve assembly 330. The first end of the switching valve 310 is connected to the oil circuit of the oil supply module 100, the first pressure receiving end of the switching valve 310 is connected to the oil circuit of the travel pilot valve assembly 220, and the second pressure receiving end of the switching valve 310 is connected to the oil circuit of the attachment pilot valve assembly 230. The oil inlet end of the travel control valve assembly 320 is connected to the oil circuits of both the oil supply module 100 and the second end of the switching valve 310, and the oil outlet end of the travel control valve assembly 320 is connected to the oil circuit of the target travel motor 410. The oil inlet end of the attachment control valve assembly 330 is connected to the oil circuits of both the oil supply module 100 and the target travel motor 410. The third end of the switching valve 310 is connected to the oil circuit, and the oil outlet of the attachment control valve group 330 is connected to the oil circuit of the target attachment 420; wherein, the switching valve 310 is used to switch the oil circuit channel between the first end and the second end of the switching valve 310 according to the target travel signal, the switching valve 310 is used to switch the oil circuit channel between the first end and the third end of the switching valve 310 according to the target attachment signal, and the switching valve 310 is used to switch the oil circuit channel between the first end and the third end of the switching valve 310 according to the target travel signal and the target attachment signal.

[0042] In this optional embodiment, the high-pressure gear pump 130 of the oil supply module 100 is connected to the first end oil circuit of the front end of the switching valve 310, thereby pumping high-pressure hydraulic oil to the switching valve 310. The second end of the rear end of the switching valve 310 is connected to the oil circuit of the travel control valve group 320, and the third end of the rear end of the switching valve 310 is connected to the oil circuit of the attachment control valve group 330. Both the travel control valve group 320 and the attachment control valve group 330 are also connected to the oil circuit of the load-sensitive main pump 120 of the oil supply module 100. The first pressure receiving end of the switching valve 310 is connected to the oil circuit of the travel pilot valve group 220, and the second pressure receiving end of the switching valve 310 is connected to the oil circuit of the attachment pilot valve group 230. The load-sensitive valve group 300 also includes a composite motion control valve group 340 for controlling the oil supply to the target composite motion device 430. Each target composite motion device 430 is equipped with a corresponding composite motion control valve group 340, and each composite motion control valve group 340 is connected to the oil circuit of the load-sensitive main pump 120 in the oil supply module 100.

[0043] When performing compound actions that do not involve attachments and travel, neither the travel pilot valve group 220 nor the attachment pilot valve group 230 sends a signal to the two pressure receiving ends of the switching valve 310. The switching valve 310 maintains its valve core in the neutral position under the action of the springs at both ends. At this time, the high-pressure pump hydraulic oil supplied by the oil supply module 100 returns through the main return oil circuit. The travel control valve group 320 and the attachment control valve group 330 are both in the closed state. Only the corresponding control valve group of the target compound action device 430 is open, so that the main pump hydraulic oil is used as the main oil source for the target compound action device 430. At this time, the load-sensitive main pump 120 in the oil supply module 100 can absorb the full torque of the construction machinery engine to supply oil for the corresponding compound action, while the high-pressure gear pump 130 does not occupy the engine torque, thereby improving the system's fuel efficiency.

[0044] When performing actions that do not involve attachments but involve walking, only the walking pilot valve assembly 220 outputs a target walking signal to the first pressure receiving end of the switching valve 310. Under the action of the target walking signal, the switching valve 310 switches to the lower position function of the valve core, thereby opening the oil passage between the first and second ends of the switching valve 310. At this time, the walking control valve assembly 320 can receive high-pressure pump hydraulic oil and merge the high-pressure pump hydraulic oil with the main pump hydraulic oil, while simultaneously opening the oil supply passage of the target walking motor 410. Under the action of the merging of high-pressure pump hydraulic oil and main pump hydraulic oil, the flow rate and execution speed of the walking action are increased.

[0045] When performing actions that do not involve walking but involve attachments, only the attachment pilot valve assembly 230 outputs a target attachment signal to the second pressure receiving end of the switching valve 310. Under the action of the target attachment signal, the switching valve 310 switches to the upper function of the valve core, thereby opening the oil passage between the first and third ends of the switching valve 310. At this time, the attachment control valve assembly 330 can receive high-pressure pump hydraulic oil and merge the high-pressure pump hydraulic oil with the main pump hydraulic oil, while simultaneously opening the oil supply passage of the target attachment 420. Under the action of the merging of high-pressure pump hydraulic oil and main pump hydraulic oil, the flow rate and execution speed of the attachment action are increased.

[0046] When performing actions involving both walking and attachments, the walking pilot valve assembly 220 outputs a target walking signal to the first pressure receiving end of the switching valve 310, while the attachment pilot valve assembly 230 outputs a target attachment signal to the second pressure receiving end of the switching valve 310. A flow-limiting device, such as a throttle orifice, can be provided between the walking pilot valve assembly 220 and the first pressure receiving end of the switching valve 310 to limit the hydraulic pressure received at the first pressure receiving end. Under the combined action of the target attachment signal and the relatively weaker target walking signal, the switching valve 310 switches to its upper-level valve function, thereby opening the oil passage between the first and third ends of the switching valve 310. At this time, the attachment control valve assembly 330 can receive high-pressure pump hydraulic oil and merge the high-pressure pump hydraulic oil with the main pump hydraulic oil, while simultaneously opening the oil supply passage to the target attachment 420, thereby ensuring that the high-pressure pump hydraulic oil can preferentially supply the target attachment 420 with additional flow.

[0047] As can be seen, this optional embodiment can also provide additional flow for attachments and walking actions that require large flow through the high-pressure pump hydraulic oil provided by the oil supply module 100. The target attachment 420 is supplied with flow first through the switching valve 310, and the target walking motor 410 is supplied with flow second. When there are no attachments or walking actions, the high-pressure pump hydraulic oil flow returns directly without occupying engine torque.

[0048] like Figure 2 As shown, in an optional embodiment, the oil supply module 100 includes: a hydraulic oil tank 110, a load-sensitive main pump 120, and a high-pressure gear pump 130. The hydraulic oil tank 110 stores initial hydraulic oil; the load-sensitive main pump 120 is connected to the hydraulic oil tank 110, the travel control valve group 320, and the attachment control valve group 330 via oil circuits, and is used to pump the initial hydraulic oil as hydraulic oil for the main pump to the travel control valve group 320 and the attachment control valve group 330; the high-pressure gear pump 130 is connected to the hydraulic oil tank 110 and the first end of the switching valve 310 via oil circuits, and is used to pump the initial hydraulic oil as hydraulic oil for the high-pressure pump to the switching valve 310.

[0049] In this optional embodiment, the initial hydraulic oil is stored in a hydraulic oil tank 110. The hydraulic oil tank 110 is connected to the hydraulic circuits of the load-sensitive main pump 120 and the high-pressure gear pump 130. The load-sensitive main pump 120 is also connected to the hydraulic circuits of the travel control valve group 320, the attachment control valve group 330, and other composite motion control valve groups 340. The high-pressure gear pump 130 is also connected to the first end of the switching valve 310. The load-sensitive main pump 120 can generate main pump hydraulic oil based on the initial hydraulic oil in the hydraulic oil tank 110 and pump it to the travel control valve group 320, the attachment control valve group 330, and other composite motion control valve groups 340. The high-pressure gear pump 130 can generate high-pressure pump hydraulic oil based on the initial hydraulic oil in the hydraulic oil tank 110 and pump it to the switching valve 310.

[0050] The torque absorption formula for this load-sensitive hydraulic system satisfies the following formula:

[0051] Where T is the engine torque, η is the torque reserve rate, n is the efficiency, V1 is the displacement of the high-pressure gear pump 130, P1 is the pressure of the high-pressure gear pump 130, V2 is the displacement of the load-sensitive main pump 120, and P2 is the pressure of the load-sensitive main pump 120. In the above formula, the displacement V1 of the high-pressure gear pump 130 is a fixed value, the efficiency n is an inherent attribute, and the pressures P1 and P2 depend on the workload. The adjustable electronically controlled displacement V2 of the load-sensitive main pump 120 reaches the torque reserve rate η preset by the control program. The torque reserve rate η can be preset according to the engine characteristics. For example, a high-power mode with the minimum torque reserve rate η under the engine's acceptable speed drop range, which can fully absorb engine torque and achieve the highest operating efficiency; or an economic mode with the torque reserve rate η under the engine's optimal fuel consumption performance, which has low fuel consumption and high economy.

[0052] In an optional embodiment, the oil supply module 100 further includes a main pump control unit. The main pump control unit is connected to the control terminal of the load-sensitive main pump 120, the travel control valve group 320, and the attachment control valve group 330 respectively. The main pump control unit is used to limit the maximum displacement of the load-sensitive main pump 120 according to the system hydraulic pressure.

[0053] In this optional embodiment, refer to Figure 2The main pump control unit may specifically include: LS valve 141, electronically controlled displacement regulator 142, pressure sensor 143, and angle sensor 144. When the construction machinery is working, LS valve 141 controls electronically controlled displacement regulator 142 to regulate the flow of the load-sensitive main pump 120. Pressure sensor 143 detects system pressure and feeds it back to the machine controller. When the pressure value reaches the preset constant power curve segment, the controller signal is transmitted to electronically controlled displacement regulator 142 to limit the maximum displacement of the main pump, ensuring that the main pump torque is within the engine's tolerance range and guaranteeing normal engine operation without speed drop. Angle sensor 144 provides real-time feedback on the main pump swashplate angle, i.e., the displacement of the load-sensitive main pump 120, ensuring the closed-loop control accuracy of electronically controlled displacement regulator 142.

[0054] like Figure 2 As shown, in an optional embodiment, the travel pilot valve assembly 220 includes: a first shuttle valve 221, a second shuttle valve 222, and a third shuttle valve 223. The first shuttle valve 221 is connected to the oil circuits of a first travel pilot oil source and a second travel pilot oil source, respectively, and is used to generate a first travel pilot signal based on the first and second travel pilot oil sources. The second shuttle valve 222 is connected to the oil circuits of a third and a fourth travel pilot oil source, respectively, and is used to generate a second travel pilot signal based on the third and fourth travel pilot oil sources. The third shuttle valve 223 is connected to the oil circuits of the first pressure receiving end of the switching valve 310, the first shuttle valve 221, and the second shuttle valve 222, respectively, and is used to generate the target travel signal based on the first travel pilot signal and the second travel pilot signal source.

[0055] In this optional embodiment, the first travel pilot oil source A1, the second travel pilot oil source A2, the third travel pilot oil source A3, and the fourth travel pilot oil source A4 can all be controlled by the operator via a pilot control lever or operating pedal in the cab of the construction machinery. The first travel pilot oil source A1 and the second travel pilot oil source A2 are both connected to the oil inlet of the first shuttle valve 221. The third travel pilot oil source A3 and the fourth travel pilot oil source A4 are both connected to the oil inlet of the second shuttle valve 222. The oil outlets of the first shuttle valve 221 and the second shuttle valve 222 are both connected to the oil inlet of the third shuttle valve 223. The oil outlet of the third shuttle valve 223 is connected to the first pressure receiving end of the switching valve 310.

[0056] The initial travel pilot signals sent by the first travel pilot oil source A1 and the second travel pilot oil source A2 are converted into a first travel pilot signal after passing through the first shuttle valve 221. The initial travel pilot signals sent by the third travel pilot oil source A3 and the fourth travel pilot oil source A4 are converted into a second travel pilot signal after passing through the second shuttle valve 222. After being delivered to the third shuttle valve 223, the third shuttle valve 223 generates a target travel signal A5 based on the first travel pilot signal and / or the second travel pilot signal, and delivers the target travel signal A5 to the first pressure receiving end of the switching valve 310.

[0057] like Figure 2 As shown, in an optional embodiment, the attachment pilot valve assembly 230 includes a fourth shuttle valve 231. The fourth shuttle valve 231 is connected to the second pressure receiving terminal of the switching valve 310, the first attachment pilot oil source, and the second attachment pilot oil source oil circuit, respectively. The fourth shuttle valve 231 is used to generate the target attachment signal based on the first attachment pilot oil source and the second attachment pilot oil source.

[0058] In this optional embodiment, both the first attachment pilot oil source B1 and the second attachment pilot oil source B2 can be controlled by the operator via a pilot control lever or operating pedal in the cab of the construction machinery. Both the first attachment pilot oil source B1 and the second attachment pilot oil source B2 are connected to the oil inlet of the fourth shuttle valve 231, and the oil outlet of the fourth shuttle valve 231 is connected to the oil inlet of the second pressure receiving end of the switching valve 310. The fourth shuttle valve 231 generates a target attachment signal B3 based on the first attachment pilot oil source B1 and / or the second attachment pilot oil source B2, and transmits the target attachment signal B3 to the second pressure receiving end of the switching valve 310.

[0059] like Figure 3 As shown, in an optional embodiment, the travel control valve assembly 320 further includes a travel main control valve 321 and a travel pressure compensation valve 322. The inlet of the travel main control valve 321 is connected to the oil circuit of the load-sensitive main pump 120; the inlet of the travel pressure compensation valve 322 is connected to the outlet of the travel main control valve 321 and the second end of the switching valve 310, respectively; the outlet of the travel pressure compensation valve 322 is connected to the first working end of the travel main control valve 321; and the second working end of the travel main control valve 321 is connected to the oil circuit of the target travel motor 410.

[0060] In this optional embodiment, each of the left-walking and right-walking hydraulic motors is equipped with a corresponding walking control valve group 320. Each walking control valve group 320 includes a walking main control valve 321 and a walking pressure compensation valve 322. The load-sensitive main pump 120 is connected to the inlet oil circuit of the walking main control valve 321. The outlet oil circuit of the walking main control valve 321 and the second end of the switching valve 310 are connected to the inlet oil circuit of the walking pressure compensation valve 322. The outlet oil circuit of the walking pressure compensation valve 322 is connected to the first working oil circuit of the walking main control valve 321. The second working oil circuit of the walking main control valve 321 is connected to the corresponding target walking motor 410.

[0061] When a movement involving only walking is required, high-pressure hydraulic oil is output from the second end of the switching valve 310. Simultaneously, the valve core of the walking main control valve 321 is switched by the walking pilot signal, making the oil passages between the inlet and outlet ends of the walking main control valve 321, as well as between the first and second working ends of the walking main control valve 321, open. The high-pressure pump hydraulic oil and the main pump hydraulic oil merge at the inlet end of the walking pressure compensation valve 322, and are then delivered to the first working end of the walking main control valve 321 through the walking pressure compensation valve 322. Finally, they are delivered from the second working end of the walking main control valve 321 to the corresponding target walking motor 410. Since the merged hydraulic oil needs to flow through the walking pressure compensation valves 322 corresponding to left and right walking, when walking left and right simultaneously is performed, the two walking motors will not deviate due to different loads.

[0062] like Figure 3 As shown, in an optional embodiment, the attachment control valve assembly 330 further includes: an attachment main control valve 331 and an attachment pressure compensation valve 332. The inlet of the attachment main control valve 331 is connected to the oil circuit of the load-sensitive main pump 120; the inlet of the attachment pressure compensation valve 332 is connected to the outlet of the attachment main control valve 331; the third end of the switching valve 310 and the outlet of the travel pressure compensation valve 322 are both connected to the first working end of the attachment main control valve 331; and the second working end of the attachment main control valve 331 is connected to the oil circuit of the target attachment 420.

[0063] In this optional embodiment, the load-sensitive main pump 120 is connected to the inlet oil circuit of the attachment main control valve 331, the outlet oil circuit of the attachment main control valve 331 is connected to the inlet oil circuit of the attachment pressure compensation valve 332, the outlet oil circuit of the attachment pressure compensation valve 332 and the third end of the switching valve 310 are connected to the first working end oil circuit of the attachment main control valve 331, and the second working end of the attachment main control valve 331 is connected to the target attachment 420 oil circuit.

[0064] When an action requiring attachment participation is needed, high-pressure pump hydraulic oil is output from the third end of switching valve 310. Simultaneously, the valve core of attachment main control valve 331 is switched by the attachment pilot signal, making the oil passages between the inlet and outlet ends of attachment main control valve 331, and between the first and second working ends of attachment main control valve 331, open. High-pressure pump hydraulic oil is delivered to the first working end of attachment main control valve 331 through attachment pressure compensation valve 332. The high-pressure pump hydraulic oil and the main pump hydraulic oil merge at the first working end of attachment main control valve 331, and finally, the hydraulic oil is delivered from the second working end of attachment main control valve 331 to the corresponding target attachment 420. Since the point where the high-pressure pump hydraulic oil and the main pump hydraulic oil merge is located before the first working end of attachment main control valve 331, the pressure loss at this merging point is smaller after the high-pressure pump hydraulic oil passes through the pressure compensation valve, thereby further increasing the flow rate received by target attachment 420 and the execution speed of target attachment 420.

[0065] The present invention also discloses an excavator, which includes a target tamping actuator and a load-sensitive hydraulic system described in the above embodiments of the present invention, wherein the load-sensitive hydraulic system is installed in the excavator body.

[0066] In this embodiment, the excavator employs the aforementioned load-sensitive hydraulic system. The load-sensitive valve group 300 controls the oil supply status of the main pump hydraulic oil and the high-pressure pump hydraulic oil to the target travel motor 410, the target attachment 420, and other composite actions. When performing composite actions not involving attachments and travel, the main pump hydraulic oil serves as the primary oil source for the system. In this case, the oil supply module 100 can absorb all engine torque to supply oil for the corresponding composite action, thereby improving fuel efficiency. Simultaneously, when performing composite actions involving attachments and / or travel, the high-pressure pump hydraulic oil and the main pump hydraulic oil are combined to jointly supply oil to the corresponding attachments and travel motor, thus supplementing the flow of the attachments and travel motor and improving their working efficiency.

[0067] The technical means disclosed in this invention are not limited to those disclosed in the above embodiments, but also include technical solutions composed of any combination of the above technical features. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of this invention, and these improvements and modifications are also considered within the scope of protection of this invention.

Claims

1. A load-sensitive hydraulic system, characterized in that, The system includes: The oil supply module is used to supply hydraulic oil to the main pump and hydraulic oil to the high-pressure pump. A pilot control module is connected to the oil supply module via an oil circuit. The pilot control module is used to provide target travel signals and target attachment signals. A load-sensitive valve assembly, which is connected to the oil supply module and the pilot control module oil circuit respectively; The target motion device includes: a target walking motor, a target attachment, and a target composite motion device, wherein the target attachment, the target walking motor, and the target composite motion device are all connected to the oil circuit of the load-sensitive valve group; The load-sensitive valve group is used to deliver the main pump hydraulic oil to the target composite motion device. The load-sensitive valve group is also used to control the merging of the high-pressure pump hydraulic oil and the main pump hydraulic oil supply channels to the target travel motor based on a separate target travel signal. Furthermore, the load-sensitive valve group is used to control the merging of the high-pressure pump hydraulic oil and the main pump hydraulic oil supply channels to the target attachment based on a separate target attachment signal. Finally, the load-sensitive valve group is used to control the merging of the high-pressure pump hydraulic oil and the main pump hydraulic oil supply channels to the target attachment based on both the target travel signal and the target attachment signal.

2. The load-sensitive hydraulic system according to claim 1, characterized in that, The pilot control module includes: A pilot oil source valve assembly, wherein the oil inlet end of the pilot oil source valve assembly is connected to the oil circuit of the oil supply module; The travel pilot valve group is connected to the travel pilot oil source, the pilot oil source valve group and the load sensitive valve group respectively. The travel pilot valve group is used to output the target travel signal to the load sensitive valve group according to the main pump hydraulic oil and the travel pilot oil source. The attachment pilot valve group is connected to the oil circuits of the attachment pilot oil source, the pilot oil source valve group and the load-sensitive valve group respectively. The attachment pilot valve group is used to output the target attachment signal to the load-sensitive valve group according to the hydraulic oil of the main pump and the attachment pilot oil source.

3. The load-sensitive hydraulic system according to claim 2, characterized in that, The load-sensitive valve assembly includes: A switching valve, wherein the first end of the switching valve is connected to the oil circuit of the oil supply module, the first pressure receiving end of the switching valve is connected to the oil circuit of the travel pilot valve group, and the second pressure receiving end of the switching valve is connected to the oil circuit of the attachment pilot valve group. The travel control valve assembly has its inlet end connected to the oil supply module and the second end oil circuit of the switching valve, respectively, and its outlet end connected to the oil circuit of the target travel motor. The attachment control valve assembly has its inlet end connected to the oil supply module and the third oil circuit of the switching valve, respectively, and its outlet end connected to the target attachment oil circuit. The switching valve is used to switch the oil passage between the first and second ends of the switching valve to be open according to the target travel signal, the switching valve is used to switch the oil passage between the first and third ends of the switching valve to be open according to the target attachment signal, and the switching valve is used to switch the oil passage between the first and third ends of the switching valve to be open according to the target travel signal and the target attachment signal.

4. The load-sensitive hydraulic system according to claim 3, characterized in that, The travel pilot valve assembly includes: The first shuttle valve is connected to the oil circuits of the first travel pilot oil source and the second travel pilot oil source respectively. The first shuttle valve is used to generate a first travel pilot signal based on the first travel pilot oil source and the second travel pilot oil source. The second shuttle valve is connected to the oil circuits of the third travel pilot oil source and the fourth travel pilot oil source respectively. The second shuttle valve is used to generate a second travel pilot signal according to the third travel pilot oil source and the fourth travel pilot oil source. The third shuttle valve is connected to the first pressure receiving end of the switching valve, the first shuttle valve, and the second shuttle valve oil circuit. The second shuttle valve is used to generate the target travel signal based on the first travel pilot signal and the second travel pilot signal source.

5. The load-sensitive hydraulic system according to claim 4, characterized in that, The accessory pilot valve assembly includes: The fourth shuttle valve is connected to the second pressure receiving end of the switching valve, the first attachment pilot oil source, and the second attachment pilot oil source oil circuit. The fourth shuttle valve is used to generate the target attachment signal based on the first attachment pilot oil source and the second attachment pilot oil source.

6. The load-sensitive hydraulic system according to any one of claims 3 to 5, characterized in that, The oil supply module includes: A hydraulic oil tank, which is used to store initial hydraulic oil; A load-sensitive main pump is connected to the hydraulic oil tank, the travel control valve group, and the attachment control valve group respectively. The load-sensitive main pump is used to pump the initial hydraulic oil as the main pump hydraulic oil to the travel control valve group and the attachment control valve group. A high-pressure gear pump is connected to the hydraulic oil tank and the first end oil circuit of the switching valve, respectively. The high-pressure gear pump is used to pump the initial hydraulic oil as the high-pressure pump hydraulic oil to the switching valve.

7. The load-sensitive hydraulic system according to claim 6, characterized in that, The travel control valve assembly also includes: The travel main control valve is connected to the oil inlet of the load-sensitive main pump. The travel pressure compensation valve has its inlet end connected to the connecting outlet end of the travel main control valve and the second end oil circuit of the switching valve, its outlet end connected to the first working end oil circuit of the travel main control valve, and its second working end connected to the target travel motor oil circuit.

8. The load-sensitive hydraulic system according to claim 7, characterized in that, The accessory control valve assembly also includes: The accessory main control valve is connected to the oil inlet of the load-sensitive main pump. The attachment pressure compensation valve has its inlet end connected to the oil circuit of the connecting outlet end of the attachment main control valve. The third end of the switching valve and the oil outlet end of the travel pressure compensation valve are both connected to the oil circuit of the first working end of the attachment main control valve. The second working end of the attachment main control valve is connected to the oil circuit of the target attachment.

9. The load-sensitive hydraulic system according to claim 6, characterized in that, The oil supply module also includes: The main pump control unit is connected to the control terminal of the load-sensitive main pump, the travel control valve group, and the attachment control valve group respectively. The main pump control unit is used to limit the maximum displacement of the load-sensitive main pump according to the system hydraulic pressure.

10. An excavator, characterized in that, The excavator includes: Excavator body; The load-sensitive hydraulic system as described in any one of claims 1 to 9, wherein the load-sensitive hydraulic system is installed in the excavator body.

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