Full-hydraulic load-sensing steering system and coal transport vehicle

Abstract

A full-hydraulic load-sensing steering system and a coal transport vehicle. The full-hydraulic load-sensing steering system comprises a hydraulic steering unit (4) connected to a steering wheel; the hydraulic steering unit (4) is connected to a flow amplifier (5) by means of a pipe; an S oil port of a piston pump (2) is connected to a hydraulic oil tank (1) by means of a pipe; a B oil port of the piston pump (2) is connected to an HP oil port of the flow amplifier (5) by means of a pipe; an X oil port of the piston pump (2) is connected to a second LS oil port of the flow amplifier (5) by means of a pipe; an HT oil port of the flow amplifier (5) is connected to the hydraulic oil tank (1) by means of a pipe; and a steering cylinder (6) is separately connected to a CL oil port and a CR oil port of the flow amplifier (5) by means of pipes.

Description

A fully hydraulic load-sensitive steering system and a coal transport vehicle

[0001] Cross-references to related applications

[0002] This application claims priority to Chinese Patent Application No. 202510139414.0, filed on February 8, 2025, the entire contents of which are incorporated herein by reference for all purposes. Technical Field

[0003] This application relates to the field of steering system technology, and in particular to a fully hydraulic load-sensitive steering system and a coal transport vehicle. Background Technology

[0004] Underground coal transport vehicles are mainly used for transporting coal in underground coal mines. They can efficiently transport coal from underground to the surface, ensuring the normal production and operation of the mining area. The traditional steering system of underground coal transport vehicles uses a plunger pump as the power element, and the steering cylinder is controlled by a manual directional valve to turn left and right.

[0005] The inventors realized that traditional steering systems use manual directional valves to control the steering cylinders for left and right steering. The driver manually controls the directional valves to turn the vehicle left and right. The steering speed and angle are difficult to control with the lever, and the vehicle is unstable when steering. Application content

[0006] This application aims to at least solve one of the technical problems in existing or related technologies where traditional steering systems use manual directional valves or similar controls to turn the steering cylinders left and right, requiring the driver to manually control the directional valves to turn the vehicle left and right, making it difficult to control the steering speed and angle with the lever, resulting in unstable vehicle steering.

[0007] Therefore, this application provides a fully hydraulic load-sensitive steering system, which adopts a load-sensitive control method. The hydraulic steering gear is combined with a flow amplifier to achieve low pressure and small flow control of high pressure and large flow. The hydraulic steering gear is controlled by the steering wheel to realize the left and right turns of the underground coal truck. The operation is smooth, the steering wheel is light, and it is highly efficient and energy-saving.

[0008] This application also provides a coal transport vehicle that includes the above-mentioned fully hydraulic load-sensitive steering system.

[0009] A fully hydraulic load-sensitive steering system according to an embodiment of the first aspect of this application includes: a hydraulic steering gear connected to a steering wheel; a first P port of the hydraulic steering gear connected to a second P port of a flow amplifier via a pipeline; a first T port of the hydraulic steering gear connected to a second T port of the flow amplifier via a pipeline; a first L port of the hydraulic steering gear connected to a second L port of the flow amplifier via a pipeline; a first R port of the hydraulic steering gear connected to a second R port of the flow amplifier via a pipeline; a first LS port of the hydraulic steering gear connected to a second LS port of the flow amplifier via a pipeline; an S port of a piston pump connected to a hydraulic oil tank via a pipeline; a B port of the piston pump connected to an HP port of the flow amplifier via a pipeline; an X port of the piston pump connected to a second LS port of the flow amplifier via a pipeline; a HT port of the flow amplifier connected to the hydraulic oil tank via a pipeline; and steering cylinders connected to the CL and CR ports of the flow amplifier via pipelines.

[0010] Optionally, the hydraulic steering gear includes: a first directional valve, configured to close the first L port and the first R port when the steering wheel is in the center position, thus closing the first directional valve; when the steering wheel is in the left turn position, to connect the first L port and the first P port, and the first R port and the first T port; and when the steering wheel is in the right turn position, to connect the first R port and the first P port, and the first L port and the first T port.

[0011] Optionally, the hydraulic steering system also includes a cycloidal motor, configured such that when the steering wheel is in the center position, the cycloidal motor is in a closed state; when the steering wheel is in a left-turn position, hydraulic fluid enters the cycloidal motor through a first directional valve, causing the cycloidal motor to assist the steering wheel in turning to the left; and when the steering wheel is in a right-turn position, hydraulic fluid enters the cycloidal motor through the first directional valve, causing the cycloidal motor to assist the steering wheel in turning to the right.

[0012] Optionally, the flow amplifier includes: a second directional valve and an amplifying valve. The second directional valve is configured such that when oil enters the second L port, the second directional valve is in a state where the CL port is connected to the amplifying valve and the CR port is connected to the HT port; when oil enters the second R port, the second directional valve is in a state where the CR port is connected to the inlet of the amplifying valve and the CL port is connected to the HT port; the amplifying valve is configured to connect to the HP port and perform flow amplification.

[0013] Optionally, the amplifying valve includes: an outer valve core and an inner valve core, with the inner valve core located inside the outer valve core; the inner valve core and the outer valve core are connected by a pipeline; the area of ​​the outer valve core is larger than that of the inner valve core.

[0014] Optionally, the flow amplifier further includes: a priority valve, the inlet of which is connected to the HP port via a pipeline; the first output port of the priority valve is connected to the first P port via a pipeline, and the second output port of the priority valve is connected to the second P port via a pipeline; the priority valve is configured such that when the pressure at the HP port is less than a preset threshold, the first output port of the priority valve is connected to the HP port; and when the pressure at the HP port is greater than the preset threshold, the first and second output ports of the priority valve are simultaneously connected to the HP port.

[0015] Optionally, the flow amplifier includes: a first buffer valve and a second buffer valve, wherein the first buffer valve is installed on the pipeline between the CL port and the HT port, and the second buffer valve is installed on the pipeline between the CR port and the HT port.

[0016] Optionally, the piston pump includes: a hydraulic pump and a load-sensitive valve, wherein the hydraulic pump is configured to draw oil from a hydraulic tank; and the load-sensitive valve is configured to adjust the output power of the hydraulic pump according to the oil pressure at port X.

[0017] Optionally, the fully hydraulic load-sensitive steering system also includes a filter located on the connection line between the B port of the piston pump and the HP port of the flow amplifier.

[0018] The second aspect of this application provides a coal transport vehicle equipped with the aforementioned fully hydraulic load-sensitive steering system. Since the fully hydraulic load-sensitive steering system has the aforementioned technical effects, the coal transport vehicle equipped with this fully hydraulic load-sensitive steering system should also have the corresponding technical effects.

[0019] One of the above technical solutions has at least the following advantages or beneficial effects:

[0020] The fully hydraulic load-sensitive steering system and coal transport vehicle provided in this application embodiment include: a hydraulic steering gear connected to a steering wheel; a first P port of the hydraulic steering gear connected to a second P port of a flow amplifier via a pipeline; a first T port of the hydraulic steering gear connected to a second T port of the flow amplifier via a pipeline; a first L port of the hydraulic steering gear connected to a second L port of the flow amplifier via a pipeline; a first R port of the hydraulic steering gear connected to a second R port of the flow amplifier via a pipeline; a first LS port of the hydraulic steering gear connected to a second LS port of the flow amplifier via a pipeline; an S port of the piston pump connected to a hydraulic oil tank via a pipeline; a B port of the piston pump connected to an HP port of the flow amplifier via a pipeline; an X port of the piston pump connected to a second LS port of the flow amplifier via a pipeline; a HT port of the flow amplifier connected to the hydraulic oil tank via a pipeline; and steering cylinders connected to the CL and CR ports of the flow amplifier via pipelines. The system employs a load-sensitive control method, combining a hydraulic steering gear with a flow amplifier to achieve low-pressure, low-flow control of high-pressure, high-flow control. The hydraulic steering gear, controlled by the steering wheel, enables the underground coal truck to turn left and right, resulting in smooth operation, a light steering wheel, and high efficiency and energy saving. Attached Figure Description

[0021] To more clearly illustrate the technical solution of this application, the drawings used in the embodiments will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 shows a schematic diagram of a fully hydraulic load-sensitive steering system provided in an embodiment of this application.

[0023] Explanation of reference numerals in the attached figures:

[0024] 1. Hydraulic oil tank; 2. Piston pump; 21. Hydraulic pump; 22. Load-sensitive valve; 3. Filter; 4. Hydraulic steering gear; 41. First directional valve; 42. Cycloidal motor; 5. Flow amplifier; 51. Second directional valve; 52. Amplifying valve; 521. Outer valve core; 522. Inner valve core; 53. Priority valve; 54. First buffer valve; 55. Second buffer valve; 56. Third buffer valve; 6. Steering cylinder. Detailed Implementation

[0025] To better explain and facilitate understanding of this application, the following detailed description of the application is provided in conjunction with the accompanying drawings and specific embodiments.

[0026] As mentioned above, traditional steering systems use manual directional valves to control the steering cylinders for left and right steering. The driver manually controls the directional valves to turn the vehicle left and right. The steering speed and angle are difficult to control with the lever, resulting in unstable vehicle steering.

[0027] To at least address one of the technical problems existing in the prior art or related technologies, this application provides a fully hydraulic load-sensitive steering system and a coal transport vehicle. The fully hydraulic load-sensitive steering system includes: a hydraulic steering gear connected to a steering wheel; a first P port of the hydraulic steering gear connected to a second P port of a flow amplifier via a pipeline; a first T port of the hydraulic steering gear connected to a second T port of the flow amplifier via a pipeline; a first L port of the hydraulic steering gear connected to a second L port of the flow amplifier via a pipeline; a first R port of the hydraulic steering gear connected to a second R port of the flow amplifier via a pipeline; a first LS port of the hydraulic steering gear connected to a second LS port of the flow amplifier via a pipeline; an S port of a piston pump connected to a hydraulic oil tank via a pipeline; a B port of the piston pump connected to an HP port of the flow amplifier via a pipeline; an X port of the piston pump connected to a second LS port of the flow amplifier via a pipeline; a HT port of the flow amplifier connected to the hydraulic oil tank via a pipeline; and steering cylinders connected to the CL and CR ports of the flow amplifier via pipelines. The system employs a load-sensitive control method, combining a hydraulic steering gear with a flow amplifier to achieve low-pressure, low-flow control of high-pressure, high-flow control. The hydraulic steering gear, controlled by the steering wheel, enables the underground coal truck to turn left and right, resulting in smooth operation, a light steering wheel, and high efficiency and energy saving.

[0028] The following describes, with reference to the accompanying drawings, some embodiments of a fully hydraulic load-sensitive steering system provided in this application.

[0029] Referring to Figure 1, an embodiment of the first aspect of this application provides a fully hydraulic load-sensitive steering system, comprising: a hydraulic steering gear 4 connected to a steering wheel; a first P port of the hydraulic steering gear 4 connected to a second P port of a flow amplifier 5 via a pipeline; a first T port of the hydraulic steering gear 4 connected to a second T port of the flow amplifier 5 via a pipeline; a first L port of the hydraulic steering gear 4 connected to a second L port of the flow amplifier 5 via a pipeline; a first R port of the hydraulic steering gear 4 connected to a second R port of the flow amplifier 5 via a pipeline; a first LS port of the hydraulic steering gear 4 connected to a second LS port of the flow amplifier 5 via a pipeline; an S port of a plunger pump 2 connected to a hydraulic oil tank 1 via a pipeline; a B port of the plunger pump 2 connected to an HP port of the flow amplifier 5 via a pipeline; an X port of the plunger pump 2 connected to a second LS port of the flow amplifier 5 via a pipeline; an HT port of the flow amplifier 5 connected to the hydraulic oil tank 1 via a pipeline; and a steering cylinder 6 connected to the CL port and CR port of the flow amplifier 5 via pipelines.

[0030] The hydraulic steering gear 4 has a first P port as the inlet, a first T port as the return port, a first L port as the left output port, a first R port as the right output port, and a first LS port as the load-sensitive control port. The steering wheel controls whether the first L and first R ports of the hydraulic steering gear 4 output hydraulic fluid. The hydraulic fluid is drawn from the hydraulic oil tank 1 by the plunger pump 2 and enters the first P port. Depending on the steering wheel direction, it enters the flow amplifier 5 through either the first L or first R port. Simultaneously, the return fluid returns to the hydraulic oil tank 1 through the first T port, forming a circulation. Controlling the hydraulic steering gear via the steering wheel enables the underground coal transport vehicle to turn left and right, resulting in smooth operation, a light steering wheel, and high efficiency and energy saving.

[0031] The second P port of the flow amplifier 5 is the inlet, the second T port is the return port, the second L port is the left input port, the second R port is the right input port, the second LS port is the load-sensitive control port, the HP port is the high-flow inlet port, and the HT port is the high-flow return port. The hydraulic fluid enters the flow amplifier 5 from either the first L port or the first R port of the hydraulic steering gear 4. The flow amplifier 5 amplifies the flow rate of the output fluid, driving the steering cylinder 6 to achieve steering. The flow amplifier 5 increases the force transmitted from the steering wheel to the steering cylinder 6, allowing the driver to achieve greater steering force control with less manual effort.

[0032] The plunger pump 2 has an S port as its inlet, a B port as its outlet, and an X port as its load-sensitive control port. The plunger pump 2 draws hydraulic fluid from the hydraulic tank 1 and senses the load pressure through the X port, thereby adjusting the output flow rate and pressure. When the load increases, the load-sensitive control causes the plunger pump 2 to output higher pressure and sufficient flow to drive the steering cylinder 6, ensuring smooth steering. When the load is low, the plunger pump 2 automatically reduces the flow rate and pressure to minimize energy loss.

[0033] In one illustrative embodiment, the hydraulic steering gear 4 includes: a first directional valve 41, configured to close the first L port and the first R port when the steering wheel is in the center position, so that the first directional valve 41 is in a closed state; when the steering wheel is in a left turn position, the first directional valve 41 is in a state where the first L port is connected to the first P port and the first R port is connected to the first T port; when the steering wheel is in a right turn position, the first directional valve 41 is in a state where the first R port is connected to the first P port and the first L port is connected to the first T port.

[0034] The first directional control valve 41 is a three-position hydraulic directional control valve. When the steering wheel is in the center position, all ports of the first directional control valve 41 are closed. At this time, neither the first L port nor the first R port can output oil to the flow amplifier 5, so the flow amplifier 5 is also in the closed state, and the steering cylinder 6 will not move. When the steering wheel is turned to the left, the valve core position of the first directional control valve 41 will change, so that the valve core is in the left position. At this time, the first directional control valve 41 will connect the first L port with the first P port, and the first R port with the first T port. This causes the oil to enter the flow amplifier 5 from the first L port. The flow amplifier 5 amplifies the flow rate of the output oil, driving the steering cylinder 6 to turn left. When the steering wheel is turned to the right, the valve core position of the first reversing valve 41 is changed, so that the valve core is in the right position. At this time, the first reversing valve 41 will connect the first R port with the first P port and the first L port with the first T port, thus causing the oil to enter the flow amplifier 5 from the first R port. The flow amplifier 5 amplifies the flow rate of the output oil, driving the steering cylinder 6 to turn right.

[0035] In one illustrative embodiment, the hydraulic steering gear 4 further includes a cycloidal motor 42, which is configured to be in a closed state when the steering wheel is in the center position; when the steering wheel is in the left turn position, hydraulic fluid enters the cycloidal motor 42 through a first reversing valve 41, causing the cycloidal motor 42 to assist the steering wheel to rotate to the left; when the steering wheel is in the right turn position, hydraulic fluid enters the cycloidal motor 42 through the first reversing valve 41, causing the cycloidal motor 42 to assist the steering wheel to rotate to the right.

[0036] The cycloidal motor 42 is a small, low-speed, high-torque hydraulic motor with an internally meshing cycloidal gear. When the first directional valve 41 supplies oil to the cycloidal motor 42, a series of mechanical transmissions cause the internally meshing gear to rotate, thereby driving the steering wheel. Specifically, the cycloidal motor 42 contains a stator and a movable vane. The stator, vane, and drive shaft divide the motor into two chambers, each with an oil port. When oil enters one port, oil exits the other, and the oil-entering port drives the vane to oscillate, thus achieving rotational motion. Because the cycloidal motor 42 has a large torque output capacity, it can effectively reduce the force required for the driver to turn the steering wheel, providing power assistance and making driving easier and safer.

[0037] In one illustrative embodiment, the flow amplifier 5 includes a second reversing valve 51 and an amplifying valve 52. The second reversing valve 51 is configured such that when oil enters the second L port, the second reversing valve 51 is in a state where the CL port is connected to the amplifying valve 52 and the CR port is connected to the HT port; when oil enters the second R port, the second reversing valve 51 is in a state where the CR port is connected to the inlet of the amplifying valve 52 and the CL port is connected to the HT port; the amplifying valve 52 is configured to connect to the HP port and perform flow amplification.

[0038] The second directional valve 51 is a three-position hydraulic directional valve. When the steering wheel is in the center position, neither the first L port nor the first R port can output fluid to the flow amplifier 5, meaning no fluid enters the second L port or the second R port. At this time, all ports of the second directional valve 51 are closed, and the steering cylinder 6 will not move. When the steering wheel is turned to the left, fluid enters from the first L port to the second L port. The entry of fluid into the second L port changes the position of the valve core of the second directional valve 51, causing the valve core to be in the left position. At this time, the CL port and... When the amplifying valve 52 is connected, the CR port and the HT port are connected, meaning the CL port outputs oil and the CR port recovers oil, driving the steering cylinder 6 to turn left. When the steering wheel is turned to the right, oil enters from the first R port to the second R port. The oil entering the second R port changes the position of the valve core of the second directional valve 51, making the valve core in the right position. At this time, the CR port is connected to the amplifying valve 52, and the CL port and the HT port are connected, meaning the CR port outputs oil and the CL port recovers oil, driving the steering cylinder 6 to turn right.

[0039] In one illustrative embodiment, the amplifying valve 52 includes an outer valve core 521 and an inner valve core 522, with the inner valve core 522 disposed inside the outer valve core 521; the inner valve core 522 and the outer valve core 521 are connected by a pipeline; the area of ​​the outer valve core 521 is larger than that of the inner valve core 522.

[0040] When a certain flow of oil is input into the inner valve core 522, the inner valve core 522 moves, and the oil pressure inside the inner valve core 522 is transmitted to the outer valve core 521 through the internal channel. Since the area of ​​the outer valve core 521 is larger than that of the inner valve core 522, under the same pressure, the output flow of the outer valve core 521 will be greater than the input flow of the inner valve core 522, thereby achieving flow amplification.

[0041] In one illustrative embodiment, the flow amplifier 5 further includes: a priority valve 53, the inlet of which is connected to the HP port via a pipeline; the first output port of the priority valve 53 is connected to the first P port via a pipeline, and the second output port of the priority valve 53 is connected to the second P port via a pipeline; the priority valve 53 is configured such that when the HP port pressure is less than a preset threshold, the first output port of the priority valve 53 is connected to the HP port; and when the HP port pressure is greater than the preset threshold, the first and second output ports of the priority valve 53 are simultaneously connected to the HP port.

[0042] Priority valve 53 can adjust the valve core position according to the oil pressure of HP port. When the pressure is lower than the preset threshold, the valve core of priority valve 53 automatically opens, connecting the first P port with the HP port, and prioritizing the supply of oil to hydraulic steering gear 4. At this time, the piston pump 2 is controlled to output higher pressure and sufficient flow through the first LS port. When the pressure is higher than the preset threshold, the relief valve opens, connecting the first P port and the second P port with the HP port at the same time, which can effectively control the system pressure and flow.

[0043] In one illustrative embodiment, the flow amplifier 5 includes a first buffer valve 54 and a second buffer valve 55. The first buffer valve 54 is disposed on the pipeline between the CL port and the HT port, and the second buffer valve 55 is disposed on the pipeline between the CR port and the HT port. The first buffer valve 54 and the second buffer valve 55 are mainly used to reduce and adjust the speed and impact force of the hydraulic fluid, protecting the steering cylinder 6 from pressure shocks and vibrations. When the pressure or flow rate of the hydraulic fluid changes, the valve cores of the first buffer valve 54 and the second buffer valve 55 will move under pressure, thereby changing the size of the passage between the valve core and the valve seat, achieving the purpose of regulating pressure and flow rate. This not only prevents the steering cylinder 6 from being damaged due to excessive pressure, but also extends the service life of other components in the system.

[0044] Furthermore, a first check valve is installed on the pipeline between the CL and HT ports. The pipeline of the first check valve is connected in parallel with the pipeline of the first buffer valve 54, and the conduction direction of the first check valve is from the HT port to the CL port. A second check valve is installed on the pipeline between the CR and HT ports. The pipeline of the second check valve is connected in parallel with the pipeline of the second buffer valve 55, and the conduction direction of the second check valve is from the HT port to the CR port. The first and second check valves can provide additional passage for the hydraulic fluid when the steering wheel suddenly changes direction, preventing a sudden change in hydraulic fluid direction from causing a sharp increase in local pressure and damaging the system.

[0045] Furthermore, the flow amplifier 5 also includes a third buffer valve 56, which is disposed on the pipeline between the second LS port and the HT port. The function of the third buffer valve 56 is the same as that of the first buffer valve 54 and the second buffer valve 55, and will not be described again here.

[0046] In one illustrative embodiment, the plunger pump 2 includes a hydraulic pump 21 and a load-sensitive valve 22. The hydraulic pump 21 is configured to draw oil from the hydraulic oil tank 1. The load-sensitive valve 22 is configured to adjust the output power of the hydraulic pump 21 according to the oil pressure at port X.

[0047] The hydraulic pump 21 provides power for the circulation of oil; the load-sensitive valve 22 senses the load pressure through the X port and transmits it to the flow control valve inside the hydraulic pump 21. According to the load pressure, the flow control valve adjusts the displacement of the hydraulic pump 21, thereby changing the output oil flow rate and pressure. This allows the outlet pressure of the hydraulic pump 21 to always be higher than the load pressure by a fixed pressure difference.

[0048] In one illustrative embodiment, the fully hydraulic load-sensitive steering system further includes a filter 3, which is installed on the connecting line between the B port of the piston pump 2 and the HP port of the flow amplifier 5. The filter 3 removes impurities from the hydraulic fluid, such as particles, dust, and metal shavings. These impurities can damage the piston pump 2, the flow amplifier 5, and other components of the entire hydraulic system, leading to performance degradation, malfunctions, or even damage. By removing impurities from the hydraulic fluid, the filter 3 protects the piston pump 2, the flow amplifier 5, and other precision components in the system from damage, extends the service life of the components, and improves the reliability and stability of the system.

[0049] In one illustrative embodiment, the steering cylinder 6 includes a left steering cylinder and a right steering cylinder. The rod-side chamber of the left steering cylinder and the rodless chamber of the right steering cylinder are connected to the CL port; the rod-side chamber of the right steering cylinder and the rodless chamber of the left steering cylinder are connected to the CR port. When fluid enters through the CL port, fluid exits through the CR port, causing the left steering cylinder to retract and the right steering cylinder to extend, completing a left turn; when fluid enters through the CR port, fluid exits through the CL port, causing the right steering cylinder to retract and the left steering cylinder to extend, completing a right turn.

[0050] Based on the fully hydraulic load-sensitive steering system provided in the above embodiments, a second aspect of this application also provides a coal transport vehicle, including the fully hydraulic load-sensitive steering system of the above embodiments. Since the coal transport vehicle provided in this embodiment has the fully hydraulic load-sensitive steering system provided in any of the above embodiments, it possesses all the beneficial effects of the fully hydraulic load-sensitive steering system provided in any of the above embodiments, which will not be elaborated further here.

[0051] In the description of this application, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0052] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; 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; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0053] In this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can mean that the first and second features are in direct contact, or that they are in indirect contact through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0054] In the description of this specification, the terms "one embodiment," "some embodiments," "embodiment," "exemplary model," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0055] Although embodiments of this application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can make modifications, alterations, substitutions and variations to the above embodiments within the scope of this application.

Claims

1. A fully hydraulic load-sensitive steering system, wherein, include: A hydraulic steering gear (4) is connected to a steering wheel; the first P port of the hydraulic steering gear (4) is connected to the second P port of the flow amplifier (5) via a pipeline; the first T port of the hydraulic steering gear (4) is connected to the second T port of the flow amplifier (5) via a pipeline; the first L port of the hydraulic steering gear (4) is connected to the second L port of the flow amplifier (5) via a pipeline; the first R port of the hydraulic steering gear (4) is connected to the second R port of the flow amplifier (5) via a pipeline; the first LS port of the hydraulic steering gear (4) is connected to the second LS port of the flow amplifier (5) via a pipeline. The S port of the plunger pump (2) is connected to the hydraulic oil tank (1) through a pipeline; the B port of the plunger pump (2) is connected to the HP port of the flow amplifier (5) through a pipeline; the X port of the plunger pump (2) is connected to the second LS port of the flow amplifier (5) through a pipeline. The HT port of the flow amplifier (5) is connected to the hydraulic oil tank (1) via a pipeline; The steering cylinder (6) is connected to the CL port and CR port of the flow amplifier (5) through pipelines.

2. The fully hydraulic load-sensitive steering system as described in claim 1, wherein, The hydraulic steering gear (4) includes: a first directional valve (41), which is configured to close the first L port and the first R port when the steering wheel is in the middle position, so that the first directional valve (41) is in the closed state; When the steering wheel is in the left turn position, the first reversing valve (41) is in the state where the first L port is connected to the first P port and the first R port is connected to the first T port. When the steering wheel is in the right turn position, the first reversing valve (41) is in a state where the first R port is connected to the first P port and the first L port is connected to the first T port.

3. The fully hydraulic load-sensitive steering system as described in claim 2, wherein, The hydraulic steering system (4) further includes a cycloidal motor (42), which is configured to be in a closed state when the steering wheel is in the center position; When the steering wheel is in the left turn position, the oil enters the cycloidal motor (42) through the first reversing valve (41), so that the cycloidal motor (42) assists the steering wheel to rotate to the left; When the steering wheel is in the right turn position, the oil enters the cycloidal motor (42) through the first reversing valve (41), causing the cycloidal motor (42) to assist the steering wheel in rotating to the right.

4. The fully hydraulic load-sensitive steering system as described in claim 1, wherein, The flow amplifier (5) includes: a second reversing valve (51) and an amplifying valve (52). The second reversing valve (51) is configured to be in a state where the second L port is connected to the amplifying valve (52) and the CR port is connected to the HT port when oil enters the second L port. When oil enters the second R port, the second reversing valve (51) is in a state where the CR port is connected to the inlet of the amplifying valve (52), and the CL port is connected to the HT port. The amplifying valve (52) is configured to connect to the HP port and amplify the flow rate.

5. A fully hydraulic load-sensitive steering system as described in claim 4, wherein, The amplifying valve (52) includes an outer valve core (521) and an inner valve core (522), wherein the inner valve core (522) is disposed inside the outer valve core (521); the inner valve core (522) and the outer valve core (521) are connected by a pipeline; the area of ​​the outer valve core (521) is larger than that of the inner valve core (522).

6. A fully hydraulic load-sensitive steering system as described in claim 4, wherein, The flow amplifier (5) further includes: a priority valve (53), the inlet of the priority valve (53) is connected to the HP port through a pipe; the first output port of the priority valve (53) is connected to the first P port through a pipe; and the second output port of the priority valve (53) is connected to the second P port through a pipe. The priority valve (53) is configured such that when the HP port pressure is less than a preset threshold, the first output port of the priority valve (53) is connected to the HP port; and when the HP port pressure is greater than the preset threshold, the first output port and the second output port of the priority valve (53) are simultaneously connected to the HP port.

7. A fully hydraulic load-sensitive steering system as described in claim 1, wherein, The flow amplifier (5) includes: a first buffer valve (54) and a second buffer valve (55), wherein the first buffer valve (54) is disposed on the pipeline between the CL port and the HT port, and the second buffer valve (55) is disposed on the pipeline between the CR port and the HT port.

8. A fully hydraulic load-sensitive steering system as described in claim 1, wherein, The plunger pump (2) includes a hydraulic pump (21) and a load-sensitive valve (22), wherein the hydraulic pump (21) is configured to draw oil from the hydraulic oil tank (1); The load-sensitive valve (22) is configured to adjust the output power of the hydraulic pump (21) according to the oil pressure at the X port.

9. A fully hydraulic load-sensitive steering system as described in claim 1, wherein, Also includes: The filter (3) is installed on the connecting pipeline between the B port of the plunger pump (2) and the HP port of the flow amplifier (5).

10. A coal transport vehicle, wherein, include: A fully hydraulic load-sensitive steering system as described in any one of claims 1-9.

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