Hydraulic steering system and working machine

Abstract

The utility model discloses hydraulic steering system and engineering machinery in the technical field of hydraulic system. Among them hydraulic steering system includes flow amplifier, steering gear, steering mechanism. Steering gear is communicated with flow amplifier through left turn oil line, right turn oil line respectively. Steering mechanism is communicated with flow amplifier through different oil line. Steering gear controls hydraulic oil to enter steering mechanism through flow amplifier, to realize nimble control engineering machinery's movement direction. The unloading mechanism is communicated with left turn oil line, right turn oil line, make when the hydraulic oil amount in left turn oil line or right turn oil line is too much, will too much hydraulic oil discharge, prevent the damage that suddenly increases's oil pressure causes to the oil line of hydraulic steering system, and when engineering machinery turns, reduce the vibration of oil line, be favorable to reduce the working noise of steering system.

Description

Technical Field

[0001] This utility model belongs to the field of hydraulic system technology, specifically relating to a hydraulic steering system and engineering machinery. Background Technology

[0002] Some large engineering wheeled machinery typically uses a hydraulic system to drive the steering mechanism, thereby controlling the direction of the machine's movement. Traditional hydraulic steering systems use directional valves to control the direction of hydraulic oil flow, enabling the steering cylinders to turn left or right.

[0003] For large construction machinery, due to the large flow of hydraulic oil required for steering, the oil supply line that controls the direction change of the directional valve is prone to vibration or even damage under large hydraulic shock, which leads to a reduction in the service life of the hydraulic steering system and excessive noise when the construction machinery is steering. Utility Model Content

[0004] The purpose of this utility model is to disclose a hydraulic steering system and engineering machinery that can reduce the adverse effects of hydraulic shock on the oil pipeline, extend the service life of the hydraulic steering system, and reduce the noise of the engineering machinery when steering.

[0005] To achieve the above objectives, this utility model discloses a hydraulic steering system, including: a flow amplifier, which is provided with an L1 oil inlet, an R1 oil inlet, a CL oil inlet, and a CR oil inlet; The steering gear is provided with an L2 oil inlet and an R2 oil inlet; the L2 oil inlet is connected to the L1 oil inlet through a left turn oil inlet, and the R2 oil inlet is connected to the R1 oil inlet through a right turn oil inlet; The steering mechanism is connected to the CL oil inlet and the CR oil inlet via oil circuits; the steering mechanism is configured to directly adjust the direction of movement of the engineering machinery. The unloading mechanism is provided with an L3 oil inlet and an R3 oil inlet; the L3 oil inlet is connected to the left-turn oil supply line, and the R3 oil inlet is connected to the right-turn oil supply line; the unloading mechanism is configured to discharge excess hydraulic oil in the left-turn oil supply line or the right-turn oil supply line.

[0006] As an optional implementation, the flow amplifier includes a reversing valve and an amplifying valve; The reversing valve is configured such that when oil enters the L1 oil inlet, the reversing valve is in a state where the CL oil inlet is connected to the flow amplifier, and the CR oil inlet is connected to the HT oil inlet on the flow amplifier; when oil enters the R1 oil inlet, the reversing valve is in a state where the CR oil inlet is connected to the amplifier valve, and the CL oil inlet is connected to the HT oil inlet. The amplifying valve is configured to connect to the HP oil inlet on the flow amplifier and serves to amplify the hydraulic oil flow rate.

[0007] As an optional implementation, the amplifying valve includes a first valve core and a second valve core, wherein the first valve core is configured to drive the second valve core to move.

[0008] As an optional implementation, the steering mechanism includes a left-turn cylinder and a right-turn cylinder; the left-turn cylinder includes a first rod-side chamber, a first rodless chamber, and a left-turn oil inlet; the right-turn cylinder includes a second rod-side chamber, a second rodless chamber, and a right-turn oil inlet; one end of the left-turn oil inlet is connected to the CL oil inlet, and the other end is divided into two paths connected to the first rod-side chamber and the second rodless chamber respectively; one end of the right-turn oil inlet is connected to the CR oil inlet, and the other end is divided into two paths connected to the first rodless chamber and the second rod-side chamber respectively.

[0009] As an optional implementation, the flow amplifier is provided with a buffer valve for each of the left-turn and right-turn cylinders respectively; the buffer valve of the left-turn cylinder is located in the oil line between the CL oil inlet and the HT oil inlet; the buffer valve of the right-turn cylinder is located in the oil line between the CR oil inlet and the HT oil inlet.

[0010] As an optional implementation, the unloading mechanism is a first unloading valve group, which includes a first shuttle valve and a two-position two-way directional valve; the oil inlets at both ends of the first shuttle valve are respectively connected to the right-turn oil supply line and the left-turn oil supply line; the oil outlet of the first shuttle valve is connected to the two-position two-way directional valve; the two-position two-way directional valve is configured to connect the left-turn oil supply line and the right-turn oil supply line when the hydraulic pressure in the left-turn oil supply line or the right-turn oil supply line is too high, so that the excess hydraulic oil flows back to the oil tank from the R3 oil supply port or the L3 oil supply port.

[0011] As an optional implementation, the unloading mechanism is a second unloading valve assembly, which includes a second shuttle valve and a second two-position three-way directional valve; the oil inlets at both ends of the second shuttle valve are respectively connected to the right-turn oil supply line and the left-turn oil supply line; the oil outlet of the second shuttle valve is connected to the second two-position three-way directional valve; the second two-position three-way directional valve is configured to connect the left-turn oil supply line and the right-turn oil supply line when the hydraulic pressure in the left-turn oil supply line or the right-turn oil supply line is too high, so that the excess hydraulic oil flows back to the oil tank from the T3 oil outlet of the unloading mechanism.

[0012] As an optional implementation, the unloading mechanism is a third unloading valve group, which includes a third shuttle valve and a sequence valve; the oil inlets at both ends of the third shuttle valve are respectively connected to the right-turn oil supply line and the left-turn oil supply line; the oil outlet of the third shuttle valve is connected to the sequence valve; the sequence valve is configured to connect the left-turn oil supply line and the right-turn oil supply line when the hydraulic pressure in the left-turn oil supply line or the right-turn oil supply line is too high, so that the excess hydraulic oil flows back to the oil tank from the R3 oil supply port or the L3 oil supply port.

[0013] As an optional implementation, the unloading mechanism is a fourth unloading valve group, which includes a damper. The two ends of the damper are respectively connected to the right-turn oil supply line and the left-turn oil supply line. The damper is configured to buffer the hydraulic oil in the left-turn oil supply line or the right-turn oil supply line when the hydraulic pressure is too high, and to allow the excess hydraulic oil to flow back to the oil tank from the R3 oil supply port or the L3 oil supply port.

[0014] Another aspect of this utility model discloses an engineering machine, including a body and the aforementioned hydraulic steering system, wherein the body controls the direction of movement of the engineering machine through the hydraulic steering system.

[0015] Compared with the prior art, the beneficial effects of this utility model are as follows: (1) The L2 and R2 oil inlets on the steering gear are connected to the L1 and R1 oil inlets on the flow amplifier via the left-turn and right-turn oil inlets, respectively. The steering mechanism is connected to the CL and CR oil inlets on the flow amplifier via different oil circuits. The steering gear controls the flow of hydraulic oil into the steering mechanism through the flow amplifier. The flow amplifier uses a small flow of hydraulic oil to adjust a large flow of hydraulic oil, and the differential pressure drives the steering mechanism to achieve flexible control of the movement direction of the engineering machinery.

[0016] (2) The L3 oil inlet and R3 oil inlet of the unloading mechanism are connected to the left turn oil supply line and the right turn oil supply line, respectively. When there is too much hydraulic oil in the left turn oil supply line or the right turn oil supply line, the unloading mechanism will discharge the excess hydraulic oil to prevent the sudden increase in oil pressure from damaging the oil circuit of the hydraulic steering system; and when the engineering machinery is turning, it will reduce the vibration of the oil circuit caused by the sudden increase in oil pressure, which will help reduce the working noise of the hydraulic steering system. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of this utility model, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a hydraulic schematic diagram of this utility model; Figure 2 This is a hydraulic schematic diagram of the flow amplifier of this utility model; Figure 3 This is a hydraulic schematic diagram of the steering mechanism of this utility model; Figure 4 This is the first hydraulic schematic diagram of the first unloading valve assembly of this utility model; Figure 5 This is the second hydraulic schematic diagram of the first unloading valve assembly of this utility model; Figure 6 This is a hydraulic schematic diagram of the second unloading valve assembly of this utility model; Figure 7 This is the hydraulic schematic diagram of the third unloading valve assembly of this utility model; Figure 8 This is the hydraulic schematic diagram of the fourth unloading valve assembly of this utility model.

[0019] Explanation of key figure labels: 1. Steering gear; 2. Flow amplifier; 21. Reversing valve; 22. Amplifying valve; 221. First valve core; 222. Second valve core; 3. Steering mechanism; 31. Left turn cylinder; 311. First rod chamber; 312. First rodless chamber; 313. Left turn oil inlet; 32. Right turn cylinder; 321. First rod chamber; 322. First rodless chamber; 323. Right turn oil inlet; 33. Buffer valve; 4. First unloading valve assembly; 41. First shuttle valve; 42. Two-position two-way directional valve; 43. First two-position three-way directional valve; 5. Second unloading valve assembly; 51. Second shuttle valve; 52. Second two-position three-way directional valve; 6. Third unloading valve assembly; 61. Third shuttle valve; 62. Sequence valve; 7. Fourth unloading valve assembly; 71. Damper; 8. Oil tank; 81. Return oil filter; 82. Oil pump; A1, right-turn oil supply line; A2, left-turn oil supply line. Detailed Implementation

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

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

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

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

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

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

[0026] Please see Figures 1 to 2 As shown, one embodiment of this application provides a hydraulic steering system, including a flow amplifier 2, a steering gear 1, an unloading mechanism, and a steering mechanism 3. The flow amplifier 2 is provided with an L1 oil inlet, an R1 oil inlet, a CL oil inlet, and a CR oil inlet; the steering gear 1 is provided with an L2 oil inlet and an R2 oil inlet. The L2 oil inlet and the L1 oil inlet are connected through a left-turn oil supply line A2, and the R2 oil inlet and the R1 oil inlet are connected through a right-turn oil supply line A1. The steering mechanism 3 is connected to the CL oil inlet and the CR oil inlet on the flow amplifier 2 through different oil lines, and the steering mechanism 3 is configured to directly adjust the direction of movement of the construction machinery.

[0027] Steering gear 1 controls the flow of hydraulic oil into steering mechanism 3 through flow amplifier 2. Flow amplifier 2 uses a small flow of hydraulic oil to adjust a large flow of hydraulic oil, and differential pressure drives steering mechanism 3 to achieve flexible control of the movement direction of engineering machinery.

[0028] The unloading mechanism is configured to drain excess hydraulic oil from either the left-turn oil supply line A2 or the right-turn oil supply line A1. The unloading mechanism has an L3 oil supply port and an R3 oil supply port. The L3 oil supply port is connected to the left-turn oil supply line A2, and the R3 oil supply port is connected to the right-turn oil supply line A1.

[0029] When the construction machinery turns left or right, the hydraulic oil volume in the left-turn oil supply line A2 or the right-turn oil supply line A1 suddenly increases. The excess hydraulic oil is discharged from the hydraulic steering system through the unloading mechanism to prevent damage to the hydraulic steering system's oil circuit due to the sudden increase in oil pressure. It also reduces the vibration of the oil circuit caused by the surge in hydraulic pressure when the construction machinery is turning, which helps to reduce the working noise of the steering system.

[0030] In some embodiments, the flow amplifier 2 is provided with an oil inlet P1 and an oil inlet T1, and the steering gear 1 is provided with an oil inlet P2 and an oil inlet T2. The oil inlet P1 and the oil inlet P2 are connected, and the oil inlet T1 and the oil inlet T2 are connected. The hydraulic steering system also includes an oil tank 8, which is provided with an oil pump 82 and a return oil filter 81.

[0031] The oil pump 82 is used to pump the hydraulic oil from the oil tank 8 into the flow amplifier 2 and the steering gear 1. The return oil filter 81 is used to filter impurities in the return hydraulic oil to ensure the purity of the hydraulic oil. The oil pump 82 is connected to the HP oil inlet and the LS1 oil inlet on the flow amplifier 2 through the oil circuit, and the return oil filter 81 is connected to the LS2 oil inlet on the steering gear 1.

[0032] Please see Figure 2 As shown, in some embodiments, the flow amplifier 2 includes a reversing valve 21 and an amplifying valve 22. The reversing valve 21 is configured such that when oil enters through the L1 port, the CL port is connected to the flow amplifier 2, and the CR port is connected to the HT port on the flow amplifier 2; when oil enters through the R1 port, the reversing valve 21 is configured such that the CR port is connected to the amplifying valve 22, and the CL port is connected to the HT port. The amplifying valve 22 is configured to connect to the HP port on the flow amplifier 2 and amplify the hydraulic oil flow rate.

[0033] The reversing valve 21 is a three-position hydraulic reversing valve. When the construction machinery needs to maintain a constant direction of movement, neither the L2 nor R2 oil inlet can output oil to the flow amplifier 2, meaning no oil enters through the L1 or R1 oil inlet. At this time, all ports of the reversing valve 21 are closed, and the steering mechanism 3 will not operate. When the construction machinery turns left, hydraulic oil enters from the L2 oil inlet to the L1 oil inlet. The hydraulic oil then passes through the L1 oil inlet and enters the reversing valve 21 along the left-turn oil path A2. The CL oil inlet is connected to the amplifying valve 22, and the CR oil inlet is connected to the HT oil inlet. That is, the CL oil inlet outputs hydraulic oil, and the CR oil inlet recovers hydraulic oil. When the construction machinery turns right, the hydraulic oil enters the R1 oil inlet from the R2 oil inlet. The hydraulic oil enters the right turn oil supply circuit A1 through the R1 oil inlet, causing the position of the reversing valve 21 to move. At this time, the CR oil inlet is connected to the amplifying valve 22, and the CL oil inlet is connected to the HT oil inlet. That is, the CR oil inlet outputs hydraulic oil, and the CL oil inlet recovers hydraulic oil.

[0034] In some embodiments, the flow amplifier 2 includes a first valve core 221 and a second valve core 222; the first valve core 221 is configured to drive the second valve core 222 to move.

[0035] Taking the left turn of construction machinery as an example, when hydraulic oil flows out of the oil tank 8, a portion flows out from the steering gear 1, moving the directional valve 21 along the left turn oil supply line A2. The hydraulic oil flows into the directional valve 21 and along the oil line to the first valve core 221, causing the first valve core 221 to move. The hydraulic oil then flows back from the first valve core 221 to the directional valve 21 and enters the left turn oil inlet line 313. After the first valve core 221 moves, a portion of the hydraulic oil flows from the first valve core 221 to the second valve core 222, causing the second valve core 222 to move. At this time, the hydraulic oil accumulated at port P1 enters the second valve core 222, passes through the first valve core 221, and enters the left turn oil inlet line 313. This enables the steering mechanism 3 to drive the construction machinery to turn left.

[0036] Please see Figure 3 As shown, in some embodiments, the steering mechanism 3 includes a left-turn cylinder 31 and a right-turn cylinder 32; the left-turn cylinder 31 includes a first rod chamber 311, a first rodless chamber 312, and a left-turn oil inlet 313; the right-turn cylinder 32 includes a second rod chamber 321, a second rodless chamber 322, and a right-turn oil inlet 323; one end of the left-turn oil inlet 313 is connected to the CL oil inlet, and the other end is divided into two paths connected to the first rod chamber 311 and the second rodless chamber 322 respectively; one end of the right-turn oil inlet 323 is connected to the CR oil inlet, and the other end is divided into two paths connected to the first rodless chamber 312 and the second rod chamber 321 respectively.

[0037] When hydraulic oil flows into the CL oil inlet and returns to the CR oil inlet, the hydraulic oil flows into the first rod chamber 311 and out of the first rodless chamber 312; the hydraulic oil flows into the second rodless chamber 322 and out of the second rod chamber 321. At this time, the left-turn cylinder 31 retracts and the right-turn cylinder 32 extends, and the construction machinery completes the left turn.

[0038] When hydraulic oil flows into the CR oil inlet and returns to the CL oil inlet, the hydraulic oil flows out of the first rod chamber 311 and into the first rodless chamber 312; the hydraulic oil flows out of the second rodless chamber 322 and into the second rod chamber 321, causing the right-turn cylinder 32 to retract and the left-turn cylinder 31 to extend, thus completing the right turn of the construction machinery.

[0039] In some embodiments, the flow amplifier 2 is equipped with a buffer valve 33 corresponding to both the left-turn cylinder 31 and the right-turn cylinder 32. The buffer valve 33 of the left-turn cylinder 31 is located in the oil line between the CL oil inlet and the HT oil inlet; the buffer valve 33 of the right-turn cylinder 32 is located in the oil line between the CR oil inlet and the HT oil inlet. The buffer valve 33 prevents excessive oil pressure from damaging the left-turn cylinder 31 or the right-turn cylinder 32, thereby extending the service life of the steering mechanism 3 and other components in the hydraulic steering system.

[0040] Please see Figure 4 The diagram shows the first hydraulic principle of the first unloading group. In some embodiments, the unloading mechanism is a first unloading valve group 4, which includes a first shuttle valve 41 and a two-position two-way directional valve 42. The oil inlets at both ends of the first shuttle valve 41 are connected to the right-turn oil supply line A1 and the left-turn oil supply line A2, respectively, and the oil outlet of the first shuttle valve 41 is connected to the two-position two-way directional valve 42. The two-position two-way directional valve 42 is configured to connect the left-turn oil supply line A2 and the right-turn oil supply line A1 when the hydraulic pressure in the left-turn oil supply line A2 or the right-turn oil supply line A1 is too high, so that the excess hydraulic oil flows back to the oil tank 8 from the R3 oil supply port or the L3 oil supply port.

[0041] When there is too much hydraulic oil in the left-turn oil supply line A2, the hydraulic oil passes through the first shuttle valve 41 and pushes the two-position two-way directional valve 42, connecting the left-turn oil supply line A2 with the right-turn oil supply line A1. The excess hydraulic oil is discharged from the R3 oil outlet into the first unloading valve assembly 4 and flows back to the oil tank 8. After the oil pressure in the left-turn oil supply line A2 returns to normal, the two-position two-way directional valve 42 returns to its initial position under the action of the return spring, disconnecting the left-turn oil supply line A2 from the right-turn oil supply line A1.

[0042] When there is too much hydraulic oil in the right-turn oil supply line A1, the hydraulic oil passes through the first shuttle valve 41 and pushes the two-position two-way directional valve 42, connecting the right-turn oil supply line A1 with the left-turn oil supply line A2. The excess hydraulic oil is discharged from the L3 oil outlet to the first unloading valve group 4 and flows back to the oil tank 8. After the oil pressure in the right-turn oil supply line A1 returns to normal, the two-position two-way directional valve 42 returns to its initial position under the action of the return spring, disconnecting the right-turn oil supply line A1 from the left-turn oil supply line A2.

[0043] Please see Figure 5 The diagram shown is a second hydraulic schematic of the first unloading group. In some embodiments, replacing the two-position two-way directional valve 42 with a first two-position three-way directional valve 43 can achieve the same technical effect as the first hydraulic schematic of the first unloading group.

[0044] Please see Figure 6 As shown, in some embodiments, the unloading mechanism is a second unloading valve group 5, which includes a second shuttle valve 51 and a second two-position three-way directional valve 52. The oil inlets at both ends of the second shuttle valve 51 are respectively connected to the right-turn oil supply line A1 and the left-turn oil supply line A2. The oil outlet of the second shuttle valve 51 is connected to the second two-position three-way directional valve 52. The second two-position three-way directional valve 52 is configured to connect the left-turn oil supply line A2 and the right-turn oil supply line A1 when the hydraulic pressure of the left-turn oil supply line A2 or the right-turn oil supply line A1 is too high, so that the excess hydraulic oil flows back to the oil tank 8 from the T3 oil outlet of the unloading mechanism.

[0045] When there is too much hydraulic oil in the left-turn oil supply line A2, the hydraulic oil passes through the second shuttle valve 51 and pushes the second two-position three-way directional valve 52, connecting the left-turn oil supply line A2 with the T3 oil supply port. The excess hydraulic oil is discharged from the T3 oil supply port through the second unloading valve assembly 5 and flows back to the oil tank 8. After the oil pressure in the left-turn oil supply line A2 returns to normal, the second two-position three-way directional valve 52 returns to its initial position under the action of the return spring, disconnecting the left-turn oil supply line A2 from the T3 oil supply port.

[0046] When there is too much hydraulic oil in the right-turn oil supply line A1, the hydraulic oil passes through the second shuttle valve 51 and pushes the second two-position three-way directional valve 52, connecting the right-turn oil supply line A1 with the T3 oil supply port. The excess hydraulic oil is discharged from the T3 oil supply port to the second unloading valve assembly 5 and flows back to the oil tank 8. After the oil pressure in the right-turn oil supply line A1 returns to normal, the second two-position three-way directional valve 52 returns to its initial position under the action of the return spring, disconnecting the right-turn oil supply line A1 from the T3 oil supply port.

[0047] Please see Figure 7As shown, in some embodiments, the unloading mechanism is a third unloading valve group 6, which includes a third shuttle valve 61 and a sequence valve 62. The oil inlets at both ends of the third shuttle valve 61 are connected to the right-turn oil supply line A1 and the left-turn oil supply line A2, respectively. The oil outlet of the third shuttle valve 61 is connected to the sequence valve 62. The sequence valve 62 is configured to connect the left-turn oil supply line A2 and the right-turn oil supply line A1 when the hydraulic pressure in the left-turn oil supply line A2 or the right-turn oil supply line A1 is too high, so that the excess hydraulic oil flows back to the oil tank 8 from the R3 oil supply port or the L3 oil supply port.

[0048] When there is too much hydraulic oil in the left-turn oil supply line A2, the hydraulic oil passes through the third shuttle valve 61 and pushes the sequence valve 62 to move, connecting the left-turn oil supply line A2 with the right-turn oil supply line A1. The excess hydraulic oil is discharged from the R3 oil outlet into the third unloading valve group 6 and flows back to the oil tank 8. After the oil pressure in the left-turn oil supply line A2 returns to normal, the sequence valve 62 returns to its initial position under the action of the return spring, disconnecting the left-turn oil supply line A2 from the right-turn oil supply line A1.

[0049] When there is too much hydraulic oil in the right-turn oil supply line A1, the hydraulic oil passes through the third shuttle valve 61 and pushes the sequence valve 62 to move, connecting the right-turn oil supply line A1 with the left-turn oil supply line A2. The excess hydraulic oil is discharged from the L3 oil outlet into the third unloading valve group 6 and flows back to the oil tank 8. After the oil pressure in the right-turn oil supply line A1 returns to normal, the sequence valve 62 returns to its initial position under the action of the return spring, disconnecting the right-turn oil supply line A1 from the left-turn oil supply line A2.

[0050] Please see Figure 8 As shown, in some embodiments, the unloading mechanism is a fourth unloading valve group 7, which includes a damper 71. The two ends of the damper 71 are respectively connected to the right-turn oil supply line A1 and the left-turn oil supply line A2. The damper 71 is configured to buffer the hydraulic oil in the left-turn oil supply line A2 or the right-turn oil supply line A1 when the hydraulic pressure is too high, and to return the excess hydraulic oil from the R3 oil supply port or the L3 oil supply port back to the oil tank 8.

[0051] When there is excessive hydraulic oil in the left-turn oil supply line A2 or the right-turn oil supply line A1, the damper 71 can provide a certain amount of fluid resistance to consume the vibration energy of the hydraulic oil, reduce sudden changes in hydraulic oil flow rate and oil pressure, thereby reducing the impact peak and protecting the hydraulic steering control system. Excess hydraulic oil can flow back to the oil tank 8 from the R3 oil supply port or the L3 oil supply port.

[0052] In some embodiments, this application provides another aspect of engineering machinery, including a body and the aforementioned hydraulic steering system. The body precisely controls the movement direction of the engineering machinery through the hydraulic steering system and reduces the operating noise of the engineering machinery when adjusting its movement direction.

[0053] The technical means disclosed in this utility model are not limited to those disclosed in the above embodiments, but also include technical solutions composed of any combination of the above technical features. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principle of this utility model, and these improvements and modifications are also considered within the scope of protection of this utility model.

Claims

1. A hydraulic steering system, characterized in that, include: The flow amplifier is equipped with an L1 oil inlet, an R1 oil inlet, a CL oil inlet, and a CR oil inlet. The steering gear is provided with an L2 oil inlet and an R2 oil inlet; the L2 oil inlet is connected to the L1 oil inlet through a left turn oil inlet, and the R2 oil inlet is connected to the R1 oil inlet through a right turn oil inlet; The steering mechanism is connected to the CL oil inlet and the CR oil inlet via oil circuits; the steering mechanism is configured to directly adjust the direction of movement of the engineering machinery. The unloading mechanism is provided with an L3 oil inlet and an R3 oil inlet; the L3 oil inlet is connected to the left-turn oil supply line, and the R3 oil inlet is connected to the right-turn oil supply line; the unloading mechanism is configured to discharge excess hydraulic oil in the left-turn oil supply line or the right-turn oil supply line.

2. The hydraulic steering system according to claim 1, characterized in that, The flow amplifier includes a reversing valve and an amplifying valve; The reversing valve is configured such that when oil enters the L1 oil inlet, the reversing valve is in a state where the CL oil inlet is connected to the flow amplifier, and the CR oil inlet is connected to the HT oil inlet on the flow amplifier; when oil enters the R1 oil inlet, the reversing valve is in a state where the CR oil inlet is connected to the amplifier valve, and the CL oil inlet is connected to the HT oil inlet. The amplifying valve is configured to connect to the HP oil inlet on the flow amplifier and serves to amplify the hydraulic oil flow rate.

3. The hydraulic steering system according to claim 2, characterized in that, The amplifying valve includes a first valve core and a second valve core, wherein the first valve core is configured to drive the second valve core to move.

4. The hydraulic steering system according to claim 1, characterized in that, The steering mechanism includes a left-turn cylinder and a right-turn cylinder; the left-turn cylinder includes a first rod-side chamber, a first rodless chamber, and a left-turn oil inlet; the right-turn cylinder includes a second rod-side chamber, a second rodless chamber, and a right-turn oil inlet; one end of the left-turn oil inlet is connected to the CL oil inlet, and the other end is divided into two paths connected to the first rod-side chamber and the second rodless chamber respectively; one end of the right-turn oil inlet is connected to the CR oil inlet, and the other end is divided into two paths connected to the first rodless chamber and the second rod-side chamber respectively.

5. The hydraulic steering system according to claim 4, characterized in that, The flow amplifier is equipped with a buffer valve corresponding to the left-turning cylinder and the right-turning cylinder respectively; the buffer valve of the left-turning cylinder is located in the oil line between the CL oil inlet and the HT oil inlet; the buffer valve of the right-turning cylinder is located in the oil line between the CR oil inlet and the HT oil inlet.

6. The hydraulic steering system according to any one of claims 1-4, characterized in that, The unloading mechanism is a first unloading valve group, which includes a first shuttle valve and a two-position two-way directional valve. The oil inlets at both ends of the first shuttle valve are respectively connected to the right-turn oil supply line and the left-turn oil supply line. The oil outlet of the first shuttle valve is connected to the two-position two-way directional valve. The two-position two-way directional valve is configured to connect the left-turn oil supply line and the right-turn oil supply line when the hydraulic pressure in the left-turn oil supply line or the right-turn oil supply line is too high, so that the excess hydraulic oil flows back to the oil tank from the R3 oil supply port or the L3 oil supply port.

7. The hydraulic steering system according to any one of claims 1-4, characterized in that, The unloading mechanism is a second unloading valve group, which includes a second shuttle valve and a second two-position three-way directional valve. The oil inlets at both ends of the second shuttle valve are respectively connected to the right-turn oil supply line and the left-turn oil supply line. The oil outlet of the second shuttle valve is connected to the second two-position three-way directional valve. The second two-position three-way directional valve is configured to connect the left-turn oil supply line and the right-turn oil supply line when the hydraulic pressure in the left-turn oil supply line or the right-turn oil supply line is too high, so that the excess hydraulic oil flows back to the oil tank from the T3 oil outlet of the unloading mechanism.

8. The hydraulic steering system according to any one of claims 1-4, characterized in that, The unloading mechanism is a third unloading valve group, which includes a third shuttle valve and a sequence valve. The oil inlets at both ends of the third shuttle valve are respectively connected to the right-turn oil supply line and the left-turn oil supply line. The oil outlet of the third shuttle valve is connected to the sequence valve. The sequence valve is configured to connect the left-turn oil supply line and the right-turn oil supply line when the hydraulic pressure in the left-turn oil supply line or the right-turn oil supply line is too high, so that the excess hydraulic oil flows back to the oil tank from the R3 oil supply port or the L3 oil supply port.

9. The hydraulic steering system according to any one of claims 1-4, characterized in that, The unloading mechanism is a fourth unloading valve group, which includes a damper. The two ends of the damper are respectively connected to the right-turn oil supply line and the left-turn oil supply line. The damper is configured to buffer the hydraulic oil in the left-turn oil supply line or the right-turn oil supply line when the hydraulic pressure is too high, and to return the excess hydraulic oil to the oil tank from the R3 oil supply port or the L3 oil supply port.

10. An engineering machinery, characterized in that, The machine includes a fuselage and a hydraulic steering system as described in any one of claims 1-9, wherein the fuselage controls the direction of movement of the construction machinery through the hydraulic steering system.

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