Hydraulic control steering system and tire crane

Abstract

The utility model discloses a kind of hydraulic control steering system and tyre crane, wherein, hydraulic control steering system includes oil supply assembly, steering control assembly and steering lock assembly, steering control assembly is connected with oil supply assembly, front wheel steering mechanism and rear wheel steering mechanism respectively through hydraulic line respectively, and for steering control front wheel steering mechanism and rear wheel steering mechanism are carried out, steering lock assembly includes lock driving cylinder and lock control valve, lock driving cylinder is set correspondingly to lock steering mechanism, lock steering mechanism is set as one of front wheel steering mechanism and rear wheel steering mechanism, lock control valve is placed between lock driving cylinder and the hydraulic line of oil supply assembly, and for in control lock driving cylinder is switched between locking or unlocking lock steering mechanism, this hydraulic control steering system can be mechanically locked to lock steering mechanism, avoid direction out of control.

Description

Technical Field

[0001] This utility model belongs to the field of vehicle steering control technology, specifically relating to a hydraulic steering system and a tire crane. Background Technology

[0002] A tire crane is a type of boom-rotating crane that uses a tire chassis for movement. To facilitate operation and movement, both the front and rear wheels of the tire chassis can be used as steering wheels. By controlling the front and rear wheels, various steering modes can be achieved, such as front-wheel steering, rear-wheel steering, four-wheel steering, and crab steering. In normal driving conditions, the tire crane uses the front-wheel steering mode, where the operator only controls the front wheels. In the front-wheel steering mode, it is necessary to ensure that the rear wheels remain centered to prevent the tire crane from losing directional control.

[0003] In existing technology, to ensure that the rear wheels of a tire crane remain centered in front-wheel steering mode, a spool valve with a neutral stop function controls the steering cylinder of the rear wheels. When the valve core is in the neutral position, both working ports of the spool valve connected to the rear wheel steering cylinder are disconnected, thereby hydraulically locking the steering cylinder and preventing the rear wheels from turning. This control method has low reliability; if the spool valve deviates, it will cause the rear wheel steering cylinder to actuate, resulting in loss of directional control. Utility Model Content

[0004] In view of the above-mentioned defects or deficiencies, this utility model provides a hydraulic steering system and a tire crane, which aims to solve the technical problems.

[0005] To achieve the above objectives, the first aspect of this utility model provides a hydraulic steering system, comprising: The oil supply assembly is used to pump hydraulic oil. The steering control assembly is connected to the oil supply assembly, the front wheel steering mechanism, and the rear wheel steering mechanism respectively via hydraulic lines, and is used to control the steering of the front wheel steering mechanism and the rear wheel steering mechanism respectively; The steering lock assembly includes a lock-up actuation cylinder and a lock-up control valve. The lock-up actuation cylinder is configured to correspond to the lock-up steering mechanism, which is configured as either a front-wheel steering mechanism or a rear-wheel steering mechanism. The lock-up control valve is located between the lock-up actuation cylinder and the hydraulic lines of the oil supply assembly, and is used to control the lock-up actuation cylinder to switch between locking and unlocking the lock-up steering mechanism.

[0006] In this embodiment of the utility model, the locking drive cylinder is set as a neutral locking cylinder. The cylinder barrel of the neutral locking cylinder is provided with a first piston and a second piston. The first piston and the second piston divide the cylinder barrel into a locking rodless chamber, an intermediate chamber and a locking rod chamber. The piston rod is connected to the first piston. The cylinder barrel is also provided with a first cylinder oil port that connects to the locking rodless chamber, a second cylinder oil port that connects to the intermediate chamber and a third cylinder oil port that connects to the locking rod chamber. The locking control valve has a locking inlet oil port, a locking return oil port and a locking working oil port. The locking inlet oil port is connected to the oil supply line of the oil supply assembly, the locking return oil port is connected to the return oil line of the oil supply assembly, the locking working oil port is connected to the first cylinder oil port and the third cylinder oil port respectively, and the second cylinder oil port is connected to the return oil line.

[0007] In this embodiment of the invention, a limiting part is provided on the steering knuckle of the locking steering mechanism. The limiting part forms a locking limiting surface. The piston rod of the center locking cylinder abuts against the locking limiting surface to limit the rotation of the steering knuckle.

[0008] In this embodiment of the utility model, the steering lock assembly further includes a floating valve group, which is connected to the two working chambers of the steering cylinder of the locking steering mechanism and the return oil circuit of the oil supply assembly, and is used to switch between controlling the connection between the two working chambers and the return oil circuit and controlling the disconnection between the two working chambers and the return oil circuit.

[0009] In this embodiment of the utility model, the floating valve group includes a first directional valve and two hydraulically controlled check valves. The first oil inlet of the first directional valve is connected to the oil supply circuit of the oil supply assembly. The first working oil port of the first directional valve is connected to the control oil ports of the two hydraulically controlled check valves respectively. The oil inlets of the two hydraulically controlled check valves are connected to the return oil circuit. The oil outlets of the two hydraulically controlled check valves are respectively connected to the two working chambers one-to-one. The first directional valve is used to control the switching between unidirectional and bidirectional conduction of the hydraulically controlled check valves.

[0010] In this embodiment of the utility model, the floating valve group includes two relief valves, the return ports of the two relief valves are connected to the return oil circuit, and the inlets of the two relief valves are respectively connected to the two working chambers one by one.

[0011] In this embodiment of the present invention, the steering control assembly includes a hydraulic steering gear and a second directional valve. The steering inlet of the hydraulic steering gear is connected to the oil supply circuit of the oil supply assembly. The second inlet of the second directional valve is connected to the first control circuit of the hydraulic steering gear. The second working port of the second directional valve is connected to the rod chamber of the first steering cylinder and the rodless chamber of the second steering cylinder of the locking directional mechanism, respectively. The third working port of the second directional valve is connected to the rodless chamber of the first steering cylinder and the rod chamber of the second steering cylinder of the locking directional mechanism, respectively. The second directional valve is used to select one of the second working port and the third working port to communicate with the second inlet port, and the other to communicate with the second return port of the second directional valve.

[0012] In this embodiment of the invention, the second directional valve is configured as an M-type directional valve with a neutral position shut-off function.

[0013] In this embodiment of the utility model, one of the front wheel steering mechanism and the rear wheel steering mechanism is configured as a locking steering mechanism, and the other is configured as a free steering mechanism. The steering control assembly also includes a third directional valve. The third oil inlet of the third directional valve is connected to the oil return port of the second directional valve. The third oil return port of the third directional valve is connected to the second control oil circuit of the hydraulic steering gear. The fourth working oil port of the third directional valve is connected to the rod chamber of the third steering cylinder and the rodless chamber of the fourth steering cylinder of the free steering mechanism, respectively. The fifth working oil port of the third directional valve is connected to the rodless chamber of the third steering cylinder and the rod chamber of the fourth steering cylinder, respectively. The third directional valve is used to select whether the third oil inlet is connected to the fourth working oil port, whether the third oil return port is connected to the fifth working oil port, or whether the third oil inlet is connected to the fourth oil inlet.

[0014] In this embodiment of the invention, the oil supply assembly includes a plunger pump and a gear pump. The plunger pump is connected to a lock-up control valve, and the gear pump is connected to a steering control assembly.

[0015] In this embodiment of the invention, the hydraulic steering system further includes a proportional control valve group located on the oil supply line of the oil supply assembly, which is used to control the flow rate of the lock-up drive cylinder.

[0016] To achieve the above objectives, a second aspect of this utility model provides a tire crane, which includes the aforementioned hydraulic steering system.

[0017] Through the above technical solution, the hydraulic steering system provided by this utility model embodiment has the following beneficial effects: When using the aforementioned hydraulic steering system, the hydraulic supply assembly pumps hydraulic oil to both the steering control assembly and the steering lock assembly. The steering control assembly is connected to the front-wheel steering mechanism and the rear-wheel steering mechanism via hydraulic lines, and controls the steering of the front and rear wheels of the vehicle respectively. Therefore, the vehicle has at least three steering modes: front-wheel steering, rear-wheel steering, and four-wheel steering. One of the two steering mechanisms acts as a locking steering mechanism. In four-wheel steering mode, the locking control valve controls the locking drive cylinder to unlock the locking steering mechanism, allowing both steering mechanisms to move freely. In either front-wheel or rear-wheel steering mode, the locking control valve controls the locking drive cylinder to limit and lock the locking steering mechanism, ensuring that the two steering wheels of the locking steering mechanism remain in a centered position. That is, only one steering wheel of the two steering mechanisms can rotate, thus preventing loss of steering control. This hydraulic steering system mechanically locks the locking steering mechanism via the locking drive cylinder, offering higher reliability compared to existing steering systems.

[0018] Other features and advantages of this invention will be described in detail in the following detailed description section. Attached Figure Description

[0019] The accompanying drawings are provided to illustrate the present invention and form part of the specification. They are used together with the following detailed description to explain the present invention, but do not constitute a limitation thereof. In the drawings: Figure 1 This is a hydraulic schematic diagram of a hydraulic steering system according to an embodiment of the present invention; Figure 2 yes Figure 1 Partial hydraulic schematic diagram of the embodiment shown; Figure 3 yes Figure 1 A partial hydraulic schematic diagram of the steering lock assembly in the illustrated embodiment; Figure 4 yes Figure 1 Hydraulic schematic diagram of the floating valve assembly in the illustrated embodiment; Figure 5 yes Figure 1 A partial hydraulic schematic diagram of the steering control assembly in the illustrated embodiment; Figure 6 yes Figure 1 Hydraulic schematic diagram of the oil supply assembly in the illustrated embodiment; Figure 7 This is a schematic diagram of the engagement between the locking drive cylinder and the steering knuckle according to one embodiment of the present invention.

[0020] Explanation of reference numerals in the attached figures Detailed Implementation

[0021] The specific embodiments of this utility model will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit the scope of this utility model.

[0022] The hydraulic steering system and tire crane of this utility model are described below with reference to the accompanying drawings.

[0023] like Figures 1 to 6 As shown, this utility model provides a hydraulic steering system, including: Oil supply assembly 1, used for pumping hydraulic oil; The steering control assembly 2 is connected to the oil supply assembly 1, the front wheel steering mechanism 5 and the rear wheel steering mechanism 4 respectively through hydraulic lines, and is used to control the steering of the front wheel steering mechanism 5 and the rear wheel steering mechanism 4 respectively. The steering lock assembly 3 includes a lock-up drive cylinder 31 and a lock-up control valve 32. The lock-up drive cylinder 31 is configured to correspond to the lock-up steering mechanism, which is configured as one of the front wheel steering mechanism 5 and the rear wheel steering mechanism 4. The lock-up control valve 32 is located between the lock-up drive cylinder 31 and the hydraulic line of the oil supply assembly 1, and is used to control the lock-up drive cylinder 31 to switch between locking or unlocking the lock-up steering mechanism.

[0024] When using the aforementioned hydraulic steering system, the oil supply assembly 1 pumps hydraulic oil to the steering control assembly 2 and the steering lock assembly 3 respectively. The steering control assembly 2 is connected to the front wheel steering mechanism 5 and the rear wheel steering mechanism 4 respectively through hydraulic lines, and controls the front and rear wheels of the vehicle to steer respectively. Thus, the vehicle has at least three steering modes: front wheel steering, rear wheel steering, and four-wheel steering. One of the two steering mechanisms acts as a locking steering mechanism. In four-wheel steering mode, the locking control valve 32 controls the locking drive cylinder 31 to unlock the locking steering mechanism, and both steering mechanisms can move freely. In low-speed operation scenarios, such as turning, U-turn, or precise positioning operations in the field, the vehicle can switch to four-wheel steering mode. After the rear wheel steering mechanism 4 is unlocked, the front and rear wheels can move in coordination according to the steering command, greatly reducing the turning radius, improving the vehicle's flexibility and ease of operation, and allowing the driver to easily complete steering operations in narrow spaces.

[0025] In front-wheel steering mode or rear-wheel steering mode, the lock-up control valve 32 controls the lock-up drive cylinder 31 to limit and lock the locking steering mechanism, ensuring that the two steering wheels of the locking steering mechanism remain in the centered position. That is, only one of the two steering mechanisms can rotate, thereby avoiding loss of steering control. This hydraulic steering system mechanically locks the locking steering mechanism through the lock-up drive cylinder 31, which is more reliable than existing steering systems.

[0026] Specifically, when the vehicle is traveling at high speed, it generally adopts the front wheel steering mode. In this case, the rear wheel steering mechanism 4 is set as a locking steering mechanism. The rear wheel steering mechanism 4 is mechanically locked by the steering lock assembly 3. Subsequent embodiments will be explained by setting the rear wheel steering mechanism 4 as a locking steering mechanism.

[0027] Furthermore, both the front wheel steering mechanism 5 and the rear wheel steering mechanism 4 include an axle and a steering cylinder. The steering cylinder is located on the axle body or the frame. The steering cylinder drives the steering knuckle 7 connected to the axle, thereby driving the steering wheel to rotate.

[0028] Furthermore, see Figure 7 The steering knuckle 7 of the rear wheel steering mechanism 4, which is a locking steering mechanism, has a locking limiting surface formed on the limiting part 71. The piston rod of the locking drive cylinder 31 abuts against the locking limiting surface to limit the rotation of the steering knuckle.

[0029] In this embodiment of the utility model, the locking drive cylinder 31 is configured as a neutral locking cylinder. The cylinder barrel of the neutral locking cylinder is provided with a first piston and a second piston. The first piston and the second piston divide the cylinder barrel into a locking rodless chamber, an intermediate chamber and a locking rod chamber. The piston rod is connected to the first piston. The cylinder barrel is also provided with a first cylinder oil port 311 connecting to the locking rodless chamber, a second cylinder oil port 312 connecting to the intermediate chamber and a third cylinder oil port 313 connecting to the locking rod chamber. The locking control valve 32 has a locking oil inlet P4, a locking oil return port T4 and a locking working oil port A4. The locking oil inlet P4 is connected to the oil supply line 14 of the oil supply assembly 1. The locking oil return port T4 is connected to the oil return line 15 of the oil supply assembly 1. The locking working oil port A4 is connected to the first cylinder oil port 311 and the third cylinder oil port 313 respectively. The second cylinder oil port 312 is connected to the oil return line 15. Compared to ordinary telescopic cylinders, the center-position locking cylinder includes a first piston and a second piston. This design can effectively prevent damage to the internal structure of the cylinder during frequent center-position locking and unlocking, and can maintain more stable mechanical positioning in the locked state, reducing displacement deviation caused by pressure fluctuations.

[0030] Specifically, when the vehicle is generally in front-wheel steering mode, the locking control valve 32 connects the locking inlet port P4 and the locking working port A4 when it is de-energized, and oil enters the locking rodless chamber and the locking rod chamber of the locking drive cylinder 31, locking the rear-wheel steering mechanism 4. When the vehicle selects four-wheel steering, rear-wheel steering, or other modes, the locking control valve 32 receives an unlocking command and is energized, the locking return port T4 connects with the locking working port A4, the locking rodless chamber and the locking rod chamber of the locking drive cylinder 31 are depressurized, and the rear-wheel steering mechanism 4 is unlocked.

[0031] In this embodiment of the invention, the steering lock assembly 3 further includes a floating valve group 33. The floating valve group 33 is connected to the two working chambers of the steering cylinder of the locking steering mechanism and the return oil passage 15 of the oil supply assembly 1, and is used to switch between controlling the connection between the two working chambers and the return oil passage 15 and controlling the disconnection between the two working chambers and the return oil passage 15. When the locking steering mechanism is in the unlocked state, the floating valve group 33 is closed, and the steering cylinder can receive oil normally. When the locking steering mechanism is in the locked state, the floating valve group 33 is open, the two working chambers of the steering cylinder are connected to the return oil passage 15 and depressurized, so that the steering cylinder is in a floating state, avoiding the steering cylinder from applying load to the steering knuckle of the locking steering mechanism, ensuring that the locking drive cylinder 31 can stably lock the steering knuckle, and preventing the locking state from failing due to residual pressure in the steering cylinder or external impact. This design, through the synergistic effect of the floating valve assembly 33, ensures the normal steering function of the locking steering mechanism when unlocking, and effectively eliminates the additional force exerted by the steering cylinder on the locking structure when locking, thereby improving the reliability and safety of the steering locking assembly 3. It is especially suitable for engineering vehicles such as tire cranes that require frequent switching of steering modes.

[0032] In this embodiment of the invention, the floating valve assembly 33 includes a first directional valve 331 and two hydraulically controlled check valves 332. The first inlet P1 of the first directional valve 331 is connected to the oil supply line 14 of the oil supply assembly 1. The first working port A1 of the first directional valve 331 is connected to the control ports of the two hydraulically controlled check valves 332. The inlets of the two hydraulically controlled check valves 332 are connected to the return oil line 15. The outlets of the two hydraulically controlled check valves 332 are respectively connected to the two working chambers. The first directional valve 331 is used to control the switching between unidirectional and bidirectional flow of the hydraulically controlled check valves 332. By controlling the on / off state of the floating valve assembly 33 hydraulically, the response speed of the floating valve assembly 33 can be improved.

[0033] Specifically, when the locking steering mechanism is locked, the first directional valve 331 is de-energized, the first inlet P1 of the first directional valve 331 is connected to the first working port A1, oil enters the control port of the hydraulic check valve 332, the valve core of the hydraulic check valve 332 is opened, allowing the hydraulic oil return port to flow in reverse to the inlet port, and the two working chambers of the steering cylinder are connected to the return oil circuit 15 for pressure relief; when the locking steering mechanism is unlocked, the first directional valve 331 is energized, the first inlet P1 is disconnected from the first working port A1, the hydraulic check valve 332 only allows hydraulic oil to flow from the inlet port to the return port in the forward direction, and the two working chambers of the steering cylinder are disconnected from the return oil circuit 15.

[0034] Of course, this utility model is not limited to this. In other specific embodiments, the floating valve group 33 can also be configured as a shut-off valve that can be electrically opened or closed.

[0035] In this embodiment of the invention, the floating valve assembly 33 includes two relief valves 333. The return ports of the two relief valves 333 are connected to the return oil circuit 15, and the inlets of the two relief valves 333 are respectively connected to the two working chambers. The relief valves 333 can automatically open when the working chamber pressure of the steering cylinder exceeds a set threshold, guiding excess hydraulic oil back to the oil tank 13 through the return oil circuit 15, thus preventing excessive pressure in the working chamber from damaging the components of the steering system and providing overload protection.

[0036] In this embodiment of the present invention, the steering control assembly 2 includes a hydraulic steering gear 21 and a second directional valve 22. The steering inlet of the hydraulic steering gear 21 is connected to the oil supply line 14 of the oil supply assembly 1. The second inlet P2 of the second directional valve 22 is connected to the first control oil line 211 of the hydraulic steering gear 21. The second working port A2 of the second directional valve 22 is connected to the rod chamber of the first steering cylinder 41 and the rodless chamber of the second steering cylinder 42 of the locking directional mechanism, respectively. The third working port B2 of the second directional valve 22 is connected to the rodless chamber of the first steering cylinder 41 and the rod chamber of the second steering cylinder 42 of the locking directional mechanism, respectively. The second directional valve 22 is used to select one of the second working port A2 and the third working port B2 to connect to the second inlet P2, and the other to connect to the second return port T2 of the second directional valve 22. The second directional valve 22 can be used to achieve synchronous control of the two steering cylinders, and to select whether the first steering cylinder 41 and the second steering cylinder 42 rotate in the same direction or in opposite directions.

[0037] Specifically, the hydraulic steering gear 21 receives steering operation commands from the driver and controls the flow direction and flow rate of hydraulic oil according to these commands. A priority valve 24 is installed on the oil supply line 14 between the hydraulic steering gear 21 and the oil supply assembly 1. The oil inlet of the hydraulic steering gear 21 is connected to the CF port of the priority valve 24 to ensure priority oil supply to the steering system. The hydraulic steering gear 21 has a first control oil line 211 and a second control oil line 212. When the driver turns the steering wheel, the valve core inside the hydraulic steering gear 21 moves accordingly, thereby changing the pressure and flow direction of the hydraulic oil in the first control oil line 211 and the second control oil line 212. This, in turn, controls the extension and retraction of the first steering cylinder 41 and the second steering cylinder 42 through the second directional valve 22, ultimately driving the tires to achieve steering action.

[0038] In this embodiment of the invention, the second directional valve 22 is configured as an M-type directional valve with a neutral-position shut-off function. When the locking steering mechanism is in the locked state, the second directional valve 22 is in the neutral-position shut-off state, and hydraulic oil will not enter the steering cylinder. Specifically, when the second directional valve 22 is in the left working position, the second oil inlet P2 is connected to the second working oil port A2, and the second oil return port T2 is connected to the third working oil port B2; when the second directional valve 22 is in the right working position, the second oil inlet P2 is connected to the third working oil port B2, and the second oil return port T2 is connected to the second working oil port A2.

[0039] In this embodiment of the utility model, one of the front wheel steering mechanism 5 and the rear wheel steering mechanism 4 is configured as a locking steering mechanism, and the other is configured as a free steering mechanism. The steering control assembly 2 also includes a third directional valve 23. The third oil inlet P3 of the third directional valve 23 is connected to the oil return port of the second directional valve 22. The third oil return port T3 of the third directional valve 23 is connected to the second control oil circuit 212 of the hydraulic steering gear 21. The fourth working oil port A3 of the third directional valve 23 is connected to the rod chamber of the third steering cylinder 51 and the rodless chamber of the fourth steering cylinder 52 of the free steering mechanism, respectively. The fifth working oil port B3 of the third directional valve 23 is connected to the rodless chamber of the third steering cylinder 51 and the rod chamber of the fourth steering cylinder 52, respectively. The third directional valve 23 is used to select the connection between the third oil inlet P3 and the fourth working oil port A3, the connection between the third oil return port T3 and the fifth working oil port B3, or the connection between the third oil inlet P3 and the fourth oil inlet. By controlling the second reversing valve 22 and the third reversing valve 23, the vehicle can be selected to operate in four steering modes: front wheel steering, rear wheel steering, four-wheel steering, and crab steering. The appropriate steering mode can be freely selected according to the road conditions.

[0040] In this embodiment of the invention, the oil supply assembly 1 includes a plunger pump 11 and a gear pump 12. The plunger pump 11 is connected to the lock-up control valve 32, and the gear pump 12 is connected to the steering control assembly 2. The plunger pump 11 has a larger flow rate and, as the main pump of the vehicle's entire hydraulic system, supplies oil to the lock-up control valve 32, resulting in a faster response speed for the lock-up drive cylinder 31. The gear pump 12 offers more precise flow control, and supplying oil to the steering control assembly 2 with the gear pump 12 can further improve the steering control efficiency.

[0041] Specifically, in the hydraulic system of the tire crane, the piston pump 11 also supplies oil to the floating valve group 33 and the actuators that control the linear extension, luffing, and hoisting of the tire crane, while the gear pump 12 supplies oil to the actuators that perform the unloading and slewing actions.

[0042] In this embodiment of the invention, the hydraulic steering system further includes a proportional control valve assembly 6 disposed on the oil supply line 14 of the oil supply assembly 1. The proportional control valve assembly 6 is used to control the flow rate of the lock-up actuation cylinder 31. By adjusting the flow rate of the lock-up actuation cylinder 31 through the proportional valve assembly, the response speed of the lock-up actuation cylinder 31 can be controlled as needed.

[0043] To achieve the above objectives, a second aspect of this utility model provides a tire crane, which includes the aforementioned hydraulic steering system. Since the tire crane employs all the technical solutions of the above embodiments, it possesses at least the aforementioned beneficial effects, which will not be elaborated upon here.

[0044] In the description of this utility model, 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 indicated technical features. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this utility model, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0045] In this utility model, unless otherwise explicitly specified and limited, the terms "installation," "connection," "joining," 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, an electrical connection, or a connection that allows communication between them; 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, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0046] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. 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.

[0047] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A hydraulic steering system, characterized in that, The hydraulic steering system includes: Oil supply assembly (1) is used to pump hydraulic oil; The steering control assembly (2) is connected to the oil supply assembly (1), the front wheel steering mechanism (5) and the rear wheel steering mechanism (4) respectively through hydraulic lines, and is used to control the front wheel steering mechanism (5) and the rear wheel steering mechanism (4) to steer respectively; The steering lock assembly (3) includes a lock drive cylinder (31) and a lock control valve (32). The lock drive cylinder (31) is configured to correspond to the lock steering mechanism, which is configured as one of the front wheel steering mechanism (5) and the rear wheel steering mechanism (4). The lock control valve (32) is located between the lock drive cylinder (31) and the hydraulic line of the oil supply assembly (1) and is used to control the lock drive cylinder (31) to switch between locking or unlocking the lock steering mechanism.

2. The hydraulic steering system according to claim 1, characterized in that, The locking drive cylinder (31) is configured as a neutral locking cylinder. A first piston and a second piston are disposed within the cylinder barrel of the neutral locking cylinder. The first piston and the second piston divide the cylinder barrel into a locking rodless chamber, an intermediate chamber, and a locking rod chamber. The cylinder barrel also has a first cylinder port (311) connecting to the locking rodless chamber, a second cylinder port (312) connecting to the intermediate chamber, and a third cylinder port (313) connecting to the locking rod chamber. The locking control valve (32) has… Locking oil inlet (P4), locking oil return port (T4) and locking working oil port (A4), the locking oil inlet (P4) is connected to the oil supply line (14) of the oil supply assembly (1), the locking oil return port (T4) is connected to the oil return line (15) of the oil supply assembly (1), the locking working oil port (A4) is connected to the first cylinder oil port (311) and the third cylinder oil port (313) respectively, and the second cylinder oil port (312) is connected to the oil return line (15).

3. The hydraulic steering system according to claim 2, characterized in that, The steering knuckle (7) of the locking steering mechanism is provided with a limiting part (71), the limiting part (71) is formed with a locking limiting surface, and the piston rod of the center locking cylinder abuts against the locking limiting surface to limit the rotation of the steering knuckle (7).

4. The hydraulic steering system according to claim 1, characterized in that, The steering lock assembly (3) further includes a floating valve group (33), which is connected to the two working chambers of the steering cylinder of the locking steering mechanism and the return oil passage (15) of the oil supply assembly (1), and is used to switch between controlling the connection of the two working chambers with the return oil passage (15) and controlling the disconnection of the two working chambers from the return oil passage (15).

5. The hydraulic steering system according to claim 4, characterized in that, The floating valve group (33) includes a first directional valve (331) and two hydraulically controlled check valves (332). The first oil inlet (P1) of the first directional valve (331) is connected to the oil supply line (14) of the oil supply assembly (1). The first working oil port (A1) of the first directional valve (331) is connected to the control oil port of the two hydraulically controlled check valves (332). The oil inlets of the two hydraulically controlled check valves (332) are connected to the return oil line (15). The oil outlets of the two hydraulically controlled check valves (332) are connected to the two working chambers respectively. The first directional valve (331) is used to control the switching between unidirectional and bidirectional flow of the hydraulically controlled check valves (332). And / or, the floating valve group (33) includes two relief valves (333), the return ports of the two relief valves (333) are connected to the return oil circuit (15), and the inlets of the two relief valves (333) are respectively connected to the two working chambers one by one.

6. The hydraulic steering system according to claim 1, characterized in that, The steering control assembly (2) includes a hydraulic steering gear (21) and a second directional valve (22). The steering inlet of the hydraulic steering gear (21) is connected to the oil supply line (14) of the oil supply assembly (1). The second inlet (P2) of the second directional valve (22) is connected to the first control line (211) of the hydraulic steering gear (21). The second working port (A2) of the second directional valve (22) is connected to the rod chamber of the first steering cylinder (41) of the locking directional mechanism and the second... The rodless chamber of the steering cylinder (42) is connected, and the third working port (B2) of the second directional valve (22) is connected to the rodless chamber of the first steering cylinder (41) and the rod chamber of the second steering cylinder (42) of the locking directional mechanism, respectively. The second directional valve (22) is used to select one of the second working port (A2) and the third working port (B2) to communicate with the second inlet port (P2), and the other to communicate with the second return port (T2) of the second directional valve (22).

7. The hydraulic steering system according to claim 6, characterized in that, The second directional valve (22) is configured as an M-type directional valve with a neutral position shut-off function.

8. The hydraulic steering system according to claim 7, characterized in that, One of the front wheel steering mechanism (5) and the rear wheel steering mechanism (4) is designated as the locking steering mechanism, and the other is designated as the free steering mechanism. The steering control assembly (2) further includes a third directional valve (23). The third inlet (P3) of the third directional valve (23) is connected to the return port of the second directional valve (22). The third return port (T3) of the third directional valve (23) is connected to the second control oil circuit (212) of the hydraulic steering gear (21). The fourth working port (A3) of the third directional valve (23) is connected to the free steering mechanism. The rod chamber of the third steering cylinder (51) and the rodless chamber of the fourth steering cylinder (52) of the steering mechanism are connected. The fifth working port (B3) of the third directional valve (23) is connected to the rodless chamber of the third steering cylinder (51) and the rod chamber of the fourth steering cylinder (52) respectively. The third directional valve (23) is used to select the third oil inlet (P3) to be connected to the fourth working port (A3), the third oil return port (T3) to be connected to the fifth working port (B3), or to select the third oil inlet (P3) to be connected to the third oil return port (T3).

9. The hydraulic steering system according to any one of claims 1 to 8, characterized in that, The oil supply assembly (1) includes a plunger pump (11) and a gear pump (12), the plunger pump (11) being connected to the lock-up control valve (32), and the gear pump (12) being connected to the steering control assembly (2); And / or, the hydraulic steering system further includes a proportional control valve group (6) disposed on the oil supply line (14) of the oil supply assembly (1), the proportional control valve group (6) being used to control the flow rate of the lock-up drive cylinder (31).

10. A tire crane, characterized in that, The tire crane includes a hydraulic steering system according to any one of claims 1 to 9.

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