Hydraulic control systems and operating machinery

Abstract

The present invention relates to the technical field of hydraulic systems, and proposes a hydraulic control system and a working machine. In the hydraulic control system, the first hydraulic pump and the oil tank are connected to the travel motor through the travel control valve, and the second hydraulic pump and the oil tank are connected to the bulldozer cylinder and the travel motor through the bulldozer control valve and the merging valve. The merging valve is provided with a merging position and a bulldozer position. In the merging position, the second hydraulic pump is connected to the travel motor through the bulldozer control valve and the merging valve; in the bulldozer position, the second hydraulic pump and the oil tank are connected to the bulldozer cylinder through the bulldozer control valve and the merging valve. Through this structural arrangement, the second hydraulic pump in the hydraulic control system for supplying oil to the bulldozer cylinder can be used as an oil source for supplying merging oil to the travel motor, which can greatly reduce system costs.

Description

Technical Field

[0001] The present invention relates to the technical field of hydraulic systems, and in particular to a hydraulic control system and an operating machine. Background Art

[0002] Excavators are important working machines. Currently, excavators typically use hydraulic control systems as their power systems. Excavators typically have a travel mode and a bulldozer mode. In travel mode, the hydraulic control system drives the travel motor. In bulldozer mode, the hydraulic control system drives the bulldozer cylinder to extend and retract. To increase the forward speed of the excavator, the existing technology usually equips the travel motor with two independent hydraulic pumps so that when needed, the two hydraulic pumps can be used to combine to supply the travel motor. This travel combining structure is relatively expensive. Summary of the Invention

[0003] The present invention provides a hydraulic control system and an operating machine, which are used to solve or improve the problem of high cost of a traveling merging structure in an existing hydraulic control system.

[0004] According to a first aspect of the present invention, a hydraulic control system is provided, including a bulldozer cylinder, a travel motor, a first hydraulic pump, a second hydraulic pump, a travel control valve, a bulldozer control valve, a merging valve, a forward merging control valve group and an oil tank.

[0005] The first hydraulic pump and the fuel tank are connected to the travel motor via the travel control valve. The second hydraulic pump and the fuel tank are connected to the bulldozer cylinder and the travel motor via the bulldozer control valve and the merging valve. The merging valve has a merging position and a bulldozer position. In the merging position, the second hydraulic pump communicates with the travel motor via the bulldozer control valve and the merging valve. In the bulldozer position, the second hydraulic pump and the fuel tank communicate with the bulldozer cylinder via the bulldozer control valve and the merging valve.

[0006] According to a hydraulic control system provided by the present invention, the second hydraulic pump and the oil tank are connected to the bulldozer control valve. The bulldozer control valve is connected to the rod chamber of the bulldozer cylinder and the travel motor, respectively, via the converging valve. The rodless chamber of the bulldozer cylinder is connected to the bulldozer control valve. In the bulldozer position, the bulldozer control valve communicates with the rod chamber of the bulldozer cylinder.

[0007] The travel control valve is provided with an advance position, and the bulldozer control valve is provided with a bulldozer retract position. The forward merging control valve assembly is connected to the forward control oil port of the travel control valve, the retract control oil port of the bulldozer control valve, and the merging control oil port of the merging valve, so that in the travel mode, the travel control valve is controlled to switch to the advance position, the bulldozer control valve is controlled to switch to the bulldozer retract position, and the merging valve is controlled to switch to the merging position.

[0008] According to a hydraulic control system provided by the present invention, the forward merging control valve group includes a forward control valve, a merging switch control valve and a bulldozer retraction control valve, and the hydraulic control system also includes a control oil source.

[0009] The control oil source is connected to the oil inlet of the forward control valve. The oil outlet of the forward control valve is connected to the forward control oil port of the travel control valve, the oil inlet of the merging switch control valve, and the oil inlet of the bulldozer retraction control valve. The oil outlet of the merging switch control valve is connected to the merging control oil port of the merging valve. The oil outlet of the bulldozer retraction control valve is connected to the retraction control oil port of the bulldozer control valve.

[0010] According to a hydraulic control system provided by the present invention, the hydraulic control system further includes a bulldozer directional control valve group. The bulldozer directional control valve group includes a first directional control valve and a second directional control valve. A shuttle valve is provided between the first directional control valve and the bulldozer retraction control valve.

[0011] The control oil source is connected to the oil inlet of the first directional control valve and the oil inlet of the second directional control valve. The oil outlet of the first directional control valve is connected to the first oil inlet of the shuttle valve. The oil outlet of the bulldozer retraction control valve is connected to the second oil inlet of the shuttle valve. The oil outlet of the shuttle valve is connected to the retraction control oil port of the bulldozer control valve. The oil outlet of the second directional control valve is connected to the extension control oil port of the bulldozer control valve.

[0012] According to the present invention, a hydraulic control system further includes a control device. The control device is connected to the merging switch control valve, the bulldozer retraction control valve, and the bulldozer directional control valve group, and is configured to control the operating states of the merging switch control valve, the bulldozer retraction control valve, and the bulldozer directional control valve group based on an operating mode of the hydraulic control system.

[0013] In the walking mode, the control device controls the merging switch control valve and the bulldozer retraction control valve to be connected and the bulldozer direction control valve group to be cut off; in the bulldozer mode, the control device controls the merging switch control valve and the bulldozer retraction control valve to be cut off.

[0014] According to a hydraulic control system provided by the present invention, the bulldozer control valve includes a first working oil port, a second working oil port, a third working oil port, and a fourth working oil port, and the merging valve includes a fifth working oil port, a sixth working oil port, and a seventh working oil port.

[0015] The first working oil port is connected to the second hydraulic pump. The second working oil port is connected to the oil tank. The third working oil port is connected to the rodless chamber of the bulldozer cylinder. The fourth working oil port is connected to the fifth working oil port. The sixth working oil port is connected to the rod chamber of the bulldozer cylinder. The seventh working oil port is connected to the first oil inlet and return port of the travel motor.

[0016] According to a hydraulic control system provided by the present invention, the bulldozer control valve is further provided with a bulldozer cut-off position and a bulldozer extension position.

[0017] When the bulldozer is in the retracted position, the first working oil port is connected to the fourth working oil port, and the second working oil port is connected to the third working oil port; when the bulldozer is in the cut-off position, the first working oil port, the second working oil port, the third working oil port and the fourth working oil port are cut off from each other; when the bulldozer is in the extended position, the first working oil port is connected to the third working oil port, and the second working oil port is connected to the fourth working oil port.

[0018] In the merging position, the fifth working oil port is communicated with the seventh working oil port; in the bulldozing position, the fifth working oil port is communicated with the sixth working oil port.

[0019] According to the present invention, a hydraulic control system further includes a reverse control valve. The control oil source is connected to the oil inlet of the reverse control valve. The oil outlet of the reverse control valve is connected to the reverse control oil port of the travel control valve. The travel control valve is connected to the first hydraulic pump, the oil tank, and the first and second oil inlet and return ports of the travel motor.

[0020] The travel control valve also has a reverse position and a stop position. In the forward position, the first hydraulic pump is connected to the first oil inlet and return port, and the second oil inlet and return port is connected to the oil tank. In the reverse position, the first hydraulic pump is connected to the second oil inlet and return port, and the first oil inlet and return port is connected to the oil tank. In the stop position, the first hydraulic pump, the oil tank, the first oil inlet and return port, and the second oil inlet and return port are mutually disconnected.

[0021] According to the present invention, a hydraulic control system further includes a foot pedal, a displacement sensor, and a speed sensor, wherein the displacement sensor is connected to the foot pedal. A control device is connected to the displacement sensor and the forward control valve and is configured to control the oil port opening of the forward control valve based on a detection result of the displacement sensor.

[0022] The speed sensor is connected to a wheel of the working machine. The control device is connected to the speed sensor and the bulldozer retraction control valve and is used to control the oil port opening of the bulldozer retraction control valve based on the detection result of the speed sensor.

[0023] According to a second aspect of the present invention, there is provided a working machine comprising the hydraulic control system described above.

[0024] In the hydraulic control system provided by the present invention, the first hydraulic pump and the oil tank are connected to the travel motor via a travel control valve. The travel control valve is used to control the connection state between the first hydraulic pump and the oil tank and the travel motor. By adjusting the working position of the travel control valve, the liquid supply state of the first hydraulic pump to the travel motor can be controlled to drive the travel motor to rotate forward or reverse. The second hydraulic pump and the oil tank are connected to the bulldozer cylinder and the travel motor via a bulldozer control valve and a merging valve. The bulldozer control valve is used to control the connection state between the second hydraulic pump and the merging valve, and the merging valve is used to control the connection state between the bulldozer control valve and the bulldozer cylinder and the travel motor. The merging valve is provided with a merging position and a bulldozer position. When forward merging is required, the bulldozer control valve is switched to a state where the second hydraulic pump can be connected to the merging valve, and the merging valve is switched to the merging position. At this time, the second hydraulic pump is connected to the travel motor, and the first hydraulic pump and the second hydraulic pump merge to supply the travel motor; when bulldozer operation is required, the bulldozer control valve is switched to a state where the second hydraulic pump can be connected to the merging valve, and the merging valve is switched to the bulldozer position. At this time, the second hydraulic pump can supply oil to the bulldozer cylinder to perform bulldozer operation.

[0025] With this structural arrangement, the second hydraulic pump in the hydraulic control system for supplying oil to the bulldozer cylinder can be used as an oil source for supplying combined oil to the travel motor, which can greatly reduce system costs.

[0026] In addition, in this hydraulic control system, in driving mode, when the merging valve is stuck in the bulldozer position and the dual pump merging cannot be achieved, the second hydraulic pump can drive the bulldozer cylinder to retract, and even if the operating machine is in driving state, no dangerous accidents will occur.

[0027] Furthermore, in the working machine provided by the present invention, since it includes the hydraulic control system as described above, it also has the advantages as described above. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0029] Figure 1 It is a system principle diagram of the hydraulic control system provided by the present invention;

[0030] Figure 2 yes Figure 1 A partial enlarged view of point A in the middle;

[0031] Figure 3 yes Figure 1 A partial enlarged view of point B in the middle;

[0032] Reference numerals:

[0033] 110, bulldozer cylinder; 120, travel motor; 210, first hydraulic pump; 220, second hydraulic pump; 230, fuel tank; 310, travel control valve; 311, forward position; 312, stop position; 313, reverse position; 320, bulldozer control valve; 321, first working oil port; 322, second working oil port; 323, third working oil port; 324, fourth working oil port; 325, bulldozer retracted position; 326, bulldozer cut-off position; 327, bulldozer extended position; 400, converging valve; 4 11. Fifth working oil port; 412. Sixth working oil port; 413. Seventh working oil port; 414. Converging position; 415. Bulldozer position; 500. Forward converging control valve group; 510. Forward control valve; 520. Converging switch control valve; 530. Bulldozer retraction control valve; 600. Bulldozer direction control valve group; 610. First directional control valve; 620. Second directional control valve; 700. Shuttle valve; 800. Reverse control valve; 910. One-way valve; 920. Pressure measuring port; 930. Hydraulic lock. DETAILED DESCRIPTION

[0034] The following embodiments of the present invention are described in further detail with reference to the accompanying drawings and examples. The following examples are used to illustrate the present invention but are not intended to limit the scope of the present invention.

[0035] In the description of the embodiments of the present invention, it should be noted that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the embodiments of the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore should not be understood as limiting the embodiments of the present invention. In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance.

[0036] In the description of the embodiments of the present invention, it should be noted that, unless otherwise specified or limited, the terms "connected" and "connection" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; mechanical connections, electrical connections; and direct connections or indirect connections through an intermediary. Those skilled in the art will understand the specific meanings of the above terms in the embodiments of the present invention based on the specific circumstances.

[0037] In the embodiments of the present invention, unless otherwise expressly specified or limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediate medium. Furthermore, a first feature being "above," "above," and "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is at a higher level than the second feature. A first feature being "below," "below," and "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is at a lower level than the second feature.

[0038] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the embodiment of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in a suitable manner in any one or more embodiments or examples. In addition, in the absence of mutual contradiction, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples to make the purpose, technical solutions and advantages of the embodiment of the present invention clearer. The technical solutions in the embodiment of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiment of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0039] The following combination Figures 1 to 3 A pressure control system and a working machine provided by an embodiment of the present invention are described. It should be understood that the following description is merely an illustrative embodiment of the present invention and does not constitute any particular limitation to the present invention.

[0040] An embodiment of the first aspect of the present invention provides a hydraulic control system, such as Figures 1 to 3 As shown, the hydraulic control system includes a bulldozer cylinder 110 , a travel motor 120 , a first hydraulic pump 210 , a second hydraulic pump 220 , a travel control valve 310 , a bulldozer control valve 320 , a merging valve 400 , a forward merging control valve group 500 and an oil tank 230 .

[0041] The first hydraulic pump 210 and the fuel tank 230 are connected to the travel motor 120 via the travel control valve 310. The second hydraulic pump 220 and the fuel tank 230 are connected to the bulldozer cylinder 110 and the travel motor 120 via the bulldozer control valve 320 and the merging valve 400. The merging valve 400 has a merging position 414 and a bulldozer position 415. In the merging position 414, the second hydraulic pump 220 is connected to the travel motor 120 via the bulldozer control valve 320 and the merging valve 400. In the bulldozer position 415, the second hydraulic pump 220 and the fuel tank 230 are connected to the bulldozer cylinder 110 via the bulldozer control valve 320 and the merging valve 400.

[0042] In the hydraulic control system provided by the present invention, the first hydraulic pump 210 and the fuel tank 230 are connected to the travel motor 120 via the travel control valve 310. The travel control valve 310 is used to control the communication between the first hydraulic pump 210 and the fuel tank 230 and the travel motor 120. By adjusting the operating position of the travel control valve 310, the hydraulic supply from the first hydraulic pump 210 to the travel motor 120 can be controlled to drive the travel motor 120 in forward or reverse rotation. The second hydraulic pump 220 and the fuel tank 230 are connected to the bulldozer cylinder 110 and the travel motor 120 via the bulldozer control valve 320 and the merging valve 400. The bulldozer control valve is used to control the communication between the second hydraulic pump 220 and the merging valve 400, and the merging valve 400 is used to control the communication between the bulldozer control valve, the bulldozer cylinder 110, and the travel motor 120. The merging valve 400 is provided with a merging position 414 and a bulldozer position 415. When forward merging is required, the bulldozer control valve is switched to a state where the second hydraulic pump 220 can be connected to the merging valve 400, and the merging valve 400 is switched to the merging position 414. At this time, the second hydraulic pump 220 is connected to the travel motor 120, and the first hydraulic pump 210 and the second hydraulic pump 220 merge to supply the travel motor 120; when bulldozer operation is required, the bulldozer control valve is switched to a state where the second hydraulic pump 220 can be connected to the merging valve 400, and the merging valve 400 is switched to the bulldozer position 415. At this time, the second hydraulic pump 220 can supply oil to the bulldozer cylinder 110 to perform bulldozer operation.

[0043] With this structural arrangement, the second hydraulic pump 220 in the hydraulic control system for supplying oil to the bulldozer cylinder 110 can be used as an oil source for supplying combined oil to the travel motor 120, which can greatly reduce system costs.

[0044] In one embodiment of the present invention, the second hydraulic pump 220 and the oil tank 230 are connected to a bulldozer control valve 320. The bulldozer control valve 320 is connected to the rod chamber of the bulldozer cylinder 110 and the travel motor 120, respectively, via a combining valve 400. The rodless chamber of the bulldozer cylinder 110 is also connected to the bulldozer control valve 320. In the bulldozer position 415, the bulldozer control valve 320 communicates with the rod chamber of the bulldozer cylinder 110.

[0045] The travel control valve 310 has an advance position 311, and the bulldozer control valve 320 has a bulldozer retracted position 325. The forward merging control valve assembly 500 is connected to the forward control oil port of the travel control valve 310, the retracted control oil port of the bulldozer control valve 320, and the merging control oil port of the merging valve 400. In travel mode, the travel control valve 310 is controlled to switch to the advance position 311, while the bulldozer control valve 320 is controlled to switch to the bulldozer retracted position 325 and the merging valve 400 is controlled to switch to the merging position 414.

[0046] Specifically, if Figures 1 to 3 As shown, the first hydraulic pump 210 and the fuel tank 230 are connected to the travel motor 120 via the travel control valve 310. The travel control valve 310 is used to control the communication between the first hydraulic pump 210 and the fuel tank 230 and the travel motor 120. The travel control valve 310 has a forward position 311. When in the forward position 311, the first hydraulic pump 210 drives the travel motor 120 to rotate in the forward direction. The second hydraulic pump 220 and the fuel tank 230 are connected to the bulldozer control valve 320. The rodless chamber of the bulldozer cylinder 110 is directly connected to the bulldozer control valve 320, while the rod chamber of the bulldozer cylinder 110 and the travel motor 120 are connected to the bulldozer control valve 320 via the combining valve 400. The bulldozer control valve 320 has a dozer retracted position 325. In this position, the second hydraulic pump 220 communicates with the oil inlet of the merging valve 400, and the rodless chamber of the bulldozer cylinder 110 communicates with the oil tank 230. The merging valve 400 has a merging position 414 and a dozer position 415. In this position, the working oil port of the bulldozer control valve 320 communicates with the travel motor 120 through the merging valve 400. In this position, the working oil port of the bulldozer control valve 320 communicates with the rod chamber of the bulldozer cylinder 110 through the merging valve 400. The forward merging control valve assembly 500 is connected to the forward control port of the travel control valve 310, the retraction control port of the bulldozer control valve 320, and the merging control port of the merging valve 400. In travel mode, the travel control valve 310 is switched to the forward position 311, while the bulldozer control valve 320 is switched to the bulldozer retraction position 325 and the merging valve 400 is switched to the merging position 414. In other words, the second hydraulic pump 220 can merge with the first hydraulic pump 210 to supply the travel motor 120 through the bulldozer retraction position 325 of the bulldozer control valve 320 and the merging position 414 of the merging valve 400.

[0047] During normal operation, when control oil is input to the forward merging control valve assembly 500, the forward merging control valve assembly 500 controls the travel control valve 310 to switch to the forward position 311, simultaneously switching the bulldozer control valve 320 to the bulldozer retracted position 325 and the merging valve 400 to the merging position 414. At this point, the first hydraulic pump 210 drives the travel motor 120 in the forward direction via the travel control valve 310. The second hydraulic pump 220 supplies oil to the travel motor 120 via the bulldozer retracted position 325 of the bulldozer control valve 320 and the merging position 414 of the merging valve 400. During this process, if the merging valve 400 fails and gets stuck in the bulldozer position 415, the first hydraulic pump 210 can still drive the travel motor 120 to rotate forward through the travel control valve 310, and the second hydraulic pump 220 supplies oil to the rod chamber of the bulldozer cylinder 110 through the bulldozer control valve 320 and the merging valve 400. The oil in the rodless chamber of the bulldozer cylinder 110 flows back to the oil tank 230 through the bulldozer control valve 320 to retract the bulldozer.

[0048] Through this structural setting, in driving mode, when the merging valve 400 is stuck in the bulldozer position 415 and cannot achieve dual pump merging, the second hydraulic pump 220 can drive the bulldozer cylinder 110 to retract, and even if the operating machine is in driving state, no dangerous accidents will occur.

[0049] In one embodiment of the present invention, the forward merging control valve assembly 500 includes a forward control valve 510 , a merging on-off control valve 520 , and a bulldozer retraction control valve 530 , and the hydraulic control system further includes a control oil source.

[0050] The control oil source is connected to the oil inlet of the forward control valve 510. The oil outlet of the forward control valve 510 is connected to the forward control oil port of the travel control valve 310, the oil inlet of the merging switch control valve 520, and the oil inlet of the bulldozer retraction control valve 530. The oil outlet of the merging switch control valve 520 is connected to the merging control oil port of the merging valve 400. The oil outlet of the bulldozer retraction control valve 530 is connected to the retraction control oil port of the bulldozer control valve 320.

[0051] In another embodiment of the present invention, the hydraulic control system further includes a dozer directional control valve assembly 600. The dozer directional control valve assembly 600 includes a first directional control valve 610 and a second directional control valve 620. A shuttle valve 700 is provided between the first directional control valve 610 and the dozer retraction control valve 530.

[0052] The control oil source is connected to the oil inlet of the first directional control valve 610 and the oil inlet of the second directional control valve 620. The oil outlet of the first directional control valve 610 is connected to the first oil inlet of the shuttle valve 700. The oil outlet of the bulldozer retraction control valve 530 is connected to the second oil inlet of the shuttle valve 700. The oil outlet of the shuttle valve 700 is connected to the retraction control oil port of the bulldozer control valve 320. The oil outlet of the second directional control valve 620 is connected to the extension control oil port of the bulldozer control valve 320.

[0053] Furthermore, in one embodiment of the present invention, the hydraulic control system further includes a control device. The control device is connected to the merging switch control valve 520, the bulldozer retraction control valve 530, and the bulldozer directional control valve group 600, and is used to control the operating states of the merging switch control valve 520, the bulldozer retraction control valve 530, and the bulldozer directional control valve group 600 based on the operating mode of the hydraulic control system.

[0054] In the walking mode, the control device controls the merging switch control valve 520 and the bulldozer retraction control valve 530 to be connected and the bulldozer direction control valve group 600 to be cut off; in the bulldozer mode, the control device controls the merging switch control valve 520 and the bulldozer retraction control valve 530 to be cut off.

[0055] Specifically, if Figure 1 and Figure 2As shown, the forward merging control valve assembly 500 includes a forward control valve 510, a merging on-off control valve 520, and a bulldozer retraction control valve 530. The oil inlet of the forward control valve 510 is connected to a control oil source, and the two oil outlets of the forward control valve 510 are connected to the oil tank 230, the oil inlet of the merging on-off control valve 520, the oil inlet of the bulldozer retraction control valve 530, and the forward control oil port of the forward control valve 510, respectively. The control oil source can be connected to the oil tank 230 through the forward control valve 510, or can be simultaneously connected to the oil inlet of the merging on-off control valve 520, the oil inlet of the bulldozer retraction control valve 530, and the forward control oil port of the forward control valve 510 through the forward control valve 510.

[0056] The oil outlet of the merging on-off control valve 520 is connected to the merging control port of the merging valve 400. A spring is installed on the other side of the spool of the merging control valve. When pressurized oil is input to the merging control port of the merging valve 400, the merging valve 400 switches to the merging position 414. When no pressurized oil is input to the merging control port of the merging valve 400, the spring switches the merging valve 400 to the bulldozing position 415.

[0057] The oil outlet of the first directional control valve 610 and the oil outlet of the bulldozer retraction control valve 530 are connected to the retraction control oil port of the bulldozer control valve 320 via the shuttle valve 700. The second directional control valve 620 is independently connected to the extension control oil port of the bulldozer control valve 320. In other words, when either the first directional control valve 610 or the bulldozer retraction control valve 530 outputs pressurized oil, the bulldozer control valve 320 can be switched to the retraction position. When the second directional control valve 620 outputs pressurized oil, the bulldozer control valve 320 can be switched to the bulldozer extension position 327.

[0058] The hydraulic control system has two operating modes: driving mode and bulldozer mode. Driving mode and bulldozer mode are manually selected by the driver, and the control device performs corresponding control actions based on the selected operating mode. Specifically, in driving mode, the control device connects the merging switch control valve 520 and the bulldozer retraction control valve 530, while the bulldozer directional control valve assembly 600 is closed. In other words, in driving mode, control fluid is input through the merging switch control valve 520 to the merging control port of the merging valve 400 and through the bulldozer retraction control valve 530 to the retraction control port of the bulldozer control valve 320, causing the merging valve 400 to switch to the merging position 414 and the bulldozer control valve 320 to switch to the bulldozer retraction position 325. Simultaneously, no control fluid is output from the bulldozer directional control valve assembly 600, and the bulldozer control valve 320 is always maintained in the bulldozer retraction position 325. This ensures driving safety.

[0059] In bulldozing mode, the control device shuts off the merging valve 520 and the bulldozer retraction valve 530. At this point, the merging valve 400 is in the bulldozing position 415. The bulldozer control valve 320's operating state is controlled by the bulldozer directional control valve assembly 600. During bulldozing operations, when the machine needs to move slowly, the first hydraulic pump 210 drives the travel motor 120.

[0060] In one embodiment of the present invention, Figure 3 As shown, the hydraulic control system also includes a reverse control valve 800. A control oil source is connected to the oil inlet of the reverse control valve 800. The oil outlet of the reverse control valve 800 is connected to the reverse control oil port of the travel control valve 310. The travel control valve 310 is connected to the first hydraulic pump 210, the oil tank 230, and the first and second oil inlet and return ports of the travel motor 120.

[0061] The travel control valve 310 also has a reverse position 313 and a stop position 312. In the forward position 311, the first hydraulic pump 210 is connected to the first oil inlet and return port, and the second oil inlet and return port is connected to the oil tank 230. In the reverse position 313, the first hydraulic pump 210 is connected to the second oil inlet and return port, and the first oil inlet and return port is connected to the oil tank 230. In the stop position 312, the first hydraulic pump 210, the oil tank 230, the first oil inlet and return port, and the second oil inlet and return port are mutually disconnected.

[0062] In one embodiment of the present invention, the bulldozer control valve 320 includes a first working oil port 321 , a second working oil port 322 , a third working oil port 323 , and a fourth working oil port 324 . The merging valve 400 includes a fifth working oil port 411 , a sixth working oil port 412 , and a seventh working oil port 413 .

[0063] The first hydraulic port 321 is connected to the second hydraulic pump 220. The second hydraulic port 322 is connected to the oil tank 230. The third hydraulic port 323 is connected to the rodless chamber of the bulldozer cylinder 110. The fourth hydraulic port 324 is connected to the fifth hydraulic port 411. The sixth hydraulic port 412 is connected to the rod chamber of the bulldozer cylinder 110. The seventh hydraulic port 413 is connected to the first oil inlet and return ports of the travel motor 120.

[0064] In another embodiment of the present invention, the bulldozer control valve 320 is further provided with a bulldozer cut-off position 326 and a bulldozer extension position 327 .

[0065] When the bulldozer is in the retracted position 325, the first working oil port 321 is connected to the fourth working oil port 324, and the second working oil port 322 is connected to the third working oil port 323; when the bulldozer is in the cut-off position 326, the first working oil port 321, the second working oil port 322, the third working oil port 323 and the fourth working oil port 324 are cut off from each other; when the bulldozer is in the extended position 327, the first working oil port 321 is connected to the third working oil port 323, and the second working oil port 322 is connected to the fourth working oil port 324.

[0066] In the merging position 414 , the fifth hydraulic oil port 411 is in communication with the seventh hydraulic oil port 413 . In the bulldozing position 415 , the fifth hydraulic oil port 411 is in communication with the sixth hydraulic oil port 412 .

[0067] Furthermore, in one embodiment of the present invention, a one-way valve 910 is provided at the seventh working oil port 413. A hydraulic lock 930 is provided on the oil circuit connecting the rod chamber and the rodless chamber of the bulldozer cylinder 110. A pressure measuring port 920 is provided on the oil circuit connecting the travel control valve 310 and the travel motor 120 to detect the cause of the failure of the hydraulic control system. For example, when the travel motor 120 is not working, if there is pressure output from the pressure measuring port 920, it indicates that there is pressure on the output side of the travel control valve 310, and the travel motor 120 may be faulty; if there is no pressure output from the pressure measuring port 920, it indicates that there is no pressure output on the output side of the travel control valve 310, and the travel control valve 310 or the first hydraulic pump 210 may be faulty.

[0068] For example, Figure 1 As shown, the bulldozer control valve 320 is a three-position, four-way reversing valve, comprising a first, second, third, and fourth hydraulic ports 321, 322, 323, and 324. The left position of the bulldozer control valve 320 is a bulldozer retracting position 325, the center position is a bulldozer closing position 326, and the right position is a bulldozer extending position 327. The merging valve 400 is a two-position, three-way reversing valve, comprising a fifth, sixth, and seventh hydraulic ports 411, 412, and 413. The left position of the merging valve 400 is a merging position 414, and the right position is a bulldozer position 415.

[0069] The first hydraulic port 321 is connected to the second hydraulic pump 220. The second hydraulic port 322 is connected to the oil tank 230. The third hydraulic port 323 is connected to the rodless chamber of the bulldozer cylinder 110. The fourth hydraulic port 324 is connected to the fifth hydraulic port 411. The sixth hydraulic port 412 is connected to the rod chamber of the bulldozer cylinder 110. The seventh hydraulic port 413 is connected to the first oil inlet and return ports of the travel motor 120.

[0070] In driving mode, the forward control valve 510 and the reverse control valve 800 control the operating position of the driving control valve, causing the first hydraulic pump 210 to drive the travel motor 120 in forward, reverse, or no rotation. When the first hydraulic pump 210 is connected to the first oil inlet and return ports via the travel control valve 310, the first hydraulic pump 210 drives the travel motor 120 in forward rotation. Generally, the required speed for forward movement of a working machine is relatively high, so the merging function is only provided during forward movement.

[0071] Furthermore, when the travel motor 120 is controlled to advance in driving mode, the merging valve 400 is simultaneously switched to the merging position 414, and the bulldozer control valve 320 is switched to the bulldozer retracted position 325. At this time, oil output from the second hydraulic pump 220 is sequentially supplied to the first oil inlet and return ports of the travel motor 120 through the first working oil port 321, the fourth working oil port 324, the fifth working oil port 411, and the seventh working oil port 413. Simultaneously, a check valve 910 at the seventh working oil port 413 prevents oil output from the first hydraulic pump 210 from backflowing into the merging valve 400. A hydraulic lock 930 is provided in the oil lines connecting the rod chamber and the rodless chamber of the bulldozer cylinder 110 to maintain the bulldozer cylinder 110 in its current position. When the merging valve 400 malfunctions and becomes stuck in the bulldozing position 415, the second hydraulic pump 220 supplies oil to the rod chamber of the bulldozer cylinder 110 through the first working oil port 321, the fourth working oil port 324, the fifth working oil port 411, and the sixth working oil port 412. The oil in the rodless chamber of the bulldozer cylinder 110 then flows back into the oil tank 230 through the third working oil port 323 and the second working oil port 322. The piston rod of the bulldozer cylinder 110 retracts. Therefore, in driving mode, when the merging valve 400 malfunctions and becomes stuck in the bulldozing position 415, the second hydraulic pump 220 can only drive the bulldozer cylinder 110 to retract, effectively preventing dangerous accidents such as the bulldozer cylinder 110 extending during driving.

[0072] In bulldozing mode, the first hydraulic pump 210 drives the travel motor 120 to adjust the working machine's position in the forward or reverse direction, while the second hydraulic pump 220 drives the bulldozer cylinder 110. The bulldozer direction control valve assembly 600 controls the operating position of the bulldozer control valve 320, thereby adjusting the direction of extension and retraction of the bulldozer cylinder 110.

[0073] In one embodiment of the present invention, the hydraulic control system further includes a foot pedal, a displacement sensor, and a speed sensor. The displacement sensor is connected to the foot pedal. A control device is connected to the displacement sensor and forward control valve 510 and is configured to control the oil port opening of forward control valve 510 based on the detection results of the displacement sensor.

[0074] The speed sensor is connected to the wheels of the working machine. The control device is connected to the speed sensor and the dozer retraction control valve 530 and is used to control the oil port opening of the dozer retraction control valve 530 based on the detection result of the speed sensor.

[0075] During operation, a foot pedal is installed in the cab of the working machine and is connected to a displacement sensor that can detect the depth of the foot pedal. The control device controls the current signal of the forward control valve 510 based on the detection results of the displacement sensor, thereby adjusting the oil port opening of the forward control valve 510. A speed sensor is installed on the wheel of the working machine to detect the driving speed of the working machine. Based on the detection results of the speed sensor, the control device can control the current signal of the bulldozer retraction control valve 530, thereby adjusting the oil port opening of the bulldozer retraction control valve 530. This changes the oil port opening of the bulldozer control valve 320 in the bulldozer retraction position 325, ultimately achieving precise adjustment of the flow rate at the point where the second hydraulic pump 220 merges with the travel motor 120.

[0076] An embodiment of the second aspect of the present invention provides a working machine including the hydraulic control system described above.

[0077] For example, the above-mentioned working machine is an excavator.

[0078] It should be noted that the above embodiment is only an illustrative embodiment of the present invention and does not constitute any limitation to the present invention. For example, the above working machine may also include a crane, a tunnel boring machine, or a loader.

[0079] Furthermore, in the working machine provided by the present invention, since it includes the hydraulic control system as described above, it also includes the advantages as described above.

[0080] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A hydraulic control system, characterized in that: It includes a bulldozer cylinder, a travel motor, a first hydraulic pump, a second hydraulic pump, a travel control valve, a bulldozer control valve, a converging valve, a forward converging control valve group and a fuel tank. The first hydraulic pump and the oil tank are connected to the travel motor through the travel control valve, and the second hydraulic pump and the oil tank are connected to the bulldozer cylinder and the travel motor through the bulldozer control valve and the merging valve. The merging valve is provided with a merging position and a bulldozer position. In the merging position, the second hydraulic pump is connected to the travel motor through the bulldozer control valve and the merging valve; in the bulldozer position, the second hydraulic pump and the oil tank are connected to the bulldozer cylinder through the bulldozer control valve and the merging valve. The walking control valve is provided with a forward position, and the bulldozer control valve is provided with a bulldozer retraction position; the forward merging control valve group is connected to the forward control oil port of the walking control valve, the retraction control oil port of the bulldozer control valve and the merging control oil port of the merging valve, so that in the walking mode, the walking control valve is controlled to switch to the forward position while controlling the bulldozer control valve to switch to the bulldozer retraction position and the merging valve to switch to the merging position.

2. The hydraulic control system according to claim 1, characterized in that: The second hydraulic pump and the oil tank are connected to the bulldozer control valve, and the bulldozer control valve is respectively connected to the rod chamber of the bulldozer cylinder and the travel motor through the merging valve. The rodless chamber of the bulldozer cylinder is connected to the bulldozer control valve. In the bulldozer position, the bulldozer control valve is connected to the rod chamber of the bulldozer cylinder.

3. The hydraulic control system according to claim 2, characterized in that: The forward merging control valve group includes a forward control valve, a merging switch control valve and a bulldozer retraction control valve, and the hydraulic control system also includes a control oil source. The control oil source is connected to the oil inlet of the forward control valve, the oil outlet of the forward control valve is connected to the forward control oil port of the travel control valve, the oil inlet of the merging switch control valve and the oil inlet of the bulldozer retraction control valve, the oil outlet of the merging switch control valve is connected to the merging control oil port of the merging valve, and the oil outlet of the bulldozer retraction control valve is connected to the retraction control oil port of the bulldozer control valve.

4. The hydraulic control system according to claim 3, characterized in that: The hydraulic control system further includes a bulldozer directional control valve group, which includes a first directional control valve and a second directional control valve. A shuttle valve is provided between the first directional control valve and the bulldozer retraction control valve. The control oil source is connected to the oil inlet of the first directional control valve and the oil inlet of the second directional control valve, the oil outlet of the first directional control valve is connected to the first oil inlet of the shuttle valve, the oil outlet of the bulldozer retraction control valve is connected to the second oil inlet of the shuttle valve, the oil outlet of the shuttle valve is connected to the retraction control oil port of the bulldozer control valve, and the oil outlet of the second directional control valve is connected to the extension control oil port of the bulldozer control valve.

5. The hydraulic control system according to claim 4, characterized in that: The hydraulic control system further includes a control device, which is connected to the confluence switch control valve, the bulldozer retraction control valve, and the bulldozer directional control valve group, and is used to control the working states of the confluence switch control valve, the bulldozer retraction control valve, and the bulldozer directional control valve group based on the working mode of the hydraulic control system. In the walking mode, the control device controls the merging switch control valve and the bulldozer retraction control valve to be connected and the bulldozer direction control valve group to be cut off; in the bulldozer mode, the control device controls the merging switch control valve and the bulldozer retraction control valve to be cut off.

6. The hydraulic control system according to claim 4, characterized in that: The bulldozer control valve includes a first working oil port, a second working oil port, a third working oil port, and a fourth working oil port, and the merging valve includes a fifth working oil port, a sixth working oil port, and a seventh working oil port. The first working oil port is connected to the second hydraulic pump, the second working oil port is connected to the oil tank, the third working oil port is connected to the rodless chamber of the bulldozer cylinder, the fourth working oil port is connected to the fifth working oil port, the sixth working oil port is connected to the rod chamber of the bulldozer cylinder, and the seventh working oil port is connected to the first inlet and return oil ports of the travel motor.

7. The hydraulic control system according to claim 6, characterized in that: The bulldozer control valve is also provided with a bulldozer cut-off position and a bulldozer extension position. In the bulldozer retracted position, the first working oil port is communicated with the fourth working oil port, and the second working oil port is communicated with the third working oil port; in the bulldozer cut-off position, the first working oil port, the second working oil port, the third working oil port, and the fourth working oil port are cut off from each other; in the bulldozer extended position, the first working oil port is communicated with the third working oil port, and the second working oil port is communicated with the fourth working oil port; In the merging position, the fifth working oil port is communicated with the seventh working oil port; in the bulldozing position, the fifth working oil port is communicated with the sixth working oil port.

8. The hydraulic control system according to claim 7, characterized in that: The hydraulic control system further includes a reverse control valve, the control oil source is connected to the oil inlet of the reverse control valve, the oil outlet of the reverse control valve is connected to the reverse control oil port of the travel control valve, and the travel control valve is connected to the first hydraulic pump, the oil tank, and the first and second oil inlet and return ports of the travel motor. The travel control valve is also provided with a retreat position and a stop position. In the forward position, the first hydraulic pump is connected to the first oil inlet and return port, and the second oil inlet and return port is connected to the oil tank; in the retreat position, the first hydraulic pump is connected to the second oil inlet and return port, and the first oil inlet and return port is connected to the oil tank; in the stop position, the first hydraulic pump, the oil tank, the first oil inlet and return port and the second oil inlet and return port are cut off from each other.

9. The hydraulic control system according to claim 5, characterized in that: The hydraulic control system further includes a foot pedal, a displacement sensor, and a speed sensor, wherein the displacement sensor is connected to the foot pedal, and the control device is connected to the displacement sensor and the forward control valve and is used to control the oil port opening of the forward control valve based on the detection result of the displacement sensor; The speed sensor is connected to the wheel of the working machine, and the control device is connected to the speed sensor and the bulldozer retraction control valve and is used to control the oil port opening of the bulldozer retraction control valve based on the detection result of the speed sensor.

10. A working machine, characterized in that: Comprising a hydraulic control system according to any one of claims 1 to 9.

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