Lower vehicle hydraulic control system and aerial work platform

Abstract

A get-off hydraulic control system comprises a hydraulic pump, a hydraulic oil tank, a get-off control valve set, a steering mechanism, a differential lock and a brake mechanism. The getting-off control valve group comprises a pressure reducing valve group, a brake control valve and a differential mechanism control valve, the pressure reducing valve group is connected with an oil outlet of the hydraulic pump, the brake mechanism is connected with the pressure reducing valve group through the brake control valve, and the differential lock is connected with the pressure reducing valve group through the differential mechanism control valve; the lower vehicle control valve group further comprises a sequence valve, a priority valve and a steering control valve, an oil inlet of the priority valve is connected with an oil outlet of the hydraulic pump, and a priority oil outlet of the priority valve is sequentially connected with the steering control valve and the steering mechanism. A secondary oil outlet of the priority valve is connected with an oil inlet of the sequence valve, an oil outlet of the sequence valve is connected with a getting-on executing mechanism, and an oil drainage port of the sequence valve is connected with the hydraulic oil tank.

Description

Technical Field

[0001] The present invention relates to the technical field of hydraulic control, and particularly to a lower vehicle hydraulic control system and an aerial work platform. Background Art

[0002] Due to its flexible mobility, energy conservation and environmental protection characteristics, the aerial work platform is widely used in various fields such as engineering construction, maintenance and equipment installation. The lower vehicle hydraulic system of such equipment is the core part to ensure its safe operation, and it needs to simultaneously meet the composite function requirements such as walking drive, steering control, brake release and differential lock unlocking and locking.

[0003] Currently, the industry generally uses a gear pump as the power source of the lower vehicle hydraulic system. The gear pump has the advantages of simple structure, reliable operation and convenient maintenance, so it is widely used in various hydraulic systems. However, in actual applications, when the vehicle is in a walking state but not performing a steering action, or the upper vehicle is not performing platform lifting, leveling and other operations, the gear pump unloads due to no load demand, resulting in the loss of standby pressure of the system. In this state, the hydraulic circuit cannot maintain the minimum pressure required to keep the brake open, seriously affecting the moving safety of the equipment; at the same time, the differential lock cannot be unlocked due to the lack of hydraulic pressure, which is likely to cause abnormal tire wear and even structural damage during operation on complex terrains.

[0004] Therefore, it is urgent to develop a lower vehicle hydraulic control system that takes into account energy consumption economy and system reliability while ensuring stable pressure supply for the brake and differential lock. Summary of the Invention

[0005] The purpose of the present invention is to enable the lower vehicle control valve to still provide the pressure required to open the brake and differential lock for the normal driving of the vehicle when the vehicle steering mechanism or the upper vehicle actuator is not operating, ensuring the driving safety of the vehicle.

[0006] To solve the problems in the prior art, in a first aspect of the present application, a lower vehicle hydraulic control system is provided, including a hydraulic pump, a hydraulic oil tank, a lower vehicle control valve group, a steering mechanism, a differential lock and a braking mechanism; The lower vehicle control valve group includes a pressure reducing valve group, a brake control valve and a differential control valve. The pressure reducing valve group is connected to the oil outlet of the hydraulic pump. The braking mechanism is connected to the pressure reducing valve group through the brake control valve. The differential lock is connected to the pressure reducing valve group through the differential control valve; The lower vehicle control valve group further includes a sequence valve, a priority valve and a steering control valve. The inlet of the priority valve is connected to the oil outlet of the hydraulic pump. The priority oil outlet of the priority valve is sequentially connected to the steering control valve and the steering mechanism; The secondary oil outlet of the priority valve is connected to the oil inlet of the sequence valve. The oil outlet of the sequence valve is connected to the upper vehicle actuator, and the drain port of the sequence valve is connected to the hydraulic oil tank.

[0007] Further, the pressure reducing valve group includes a first pressure reducing valve and a second pressure reducing valve. The oil inlet of the first pressure reducing valve is connected to the oil outlet of the hydraulic pump. The oil outlet of the first pressure reducing valve is connected to the oil inlet of the differential control valve, and the oil outlet of the differential control valve is connected to the differential lock.

[0008] Further, the oil outlet of the first pressure reducing valve is connected to the oil inlet of the second pressure reducing valve. The oil outlet of the secondary pressure reducing valve is connected to the oil inlet of the brake control valve, and the oil outlet of the brake control valve is connected to the brake mechanism.

[0009] Further, the lower vehicle control valve group further includes a first relief valve. The oil inlet of the first relief valve is connected to the oil outlet of the hydraulic pump, and the oil drain port of the first relief valve is connected to the hydraulic oil tank.

[0010] Further, the lower vehicle control valve group further includes a second relief valve. The oil inlet of the second relief valve is connected to the oil outlet of the first pressure reducing valve, and the oil drain port of the second relief valve is connected to the hydraulic oil tank.

[0011] Further, the steering mechanism includes a rear steering cylinder and a front steering cylinder. The steering control valve includes a three-position five-way solenoid valve and a three-position four-way solenoid valve. The three-position five-way solenoid valve, the front steering cylinder, the three-position four-way solenoid valve, and the rear steering cylinder are connected in sequence, and the three-position five-way solenoid valve is connected to the three-position four-way solenoid valve.

[0012] Further, the steering control valve further includes a reversing valve. The reversing valve is connected between the front steering cylinder and the three-position four-way solenoid valve, and the reversing valve is connected to the hydraulic oil tank.

[0013] Further, the principle of the lower vehicle control valve further includes a left balance cylinder and a right balance cylinder. Both the left balance cylinder and the right balance cylinder are connected to the oil outlet of the first pressure reducing valve.

[0014] Further, a pressure measuring device is connected to the oil outlet of the hydraulic pump and the oil outlet of the first pressure reducing valve.

[0015] The second aspect of the present application provides an aerial work platform, including the above-mentioned lower vehicle hydraulic control system.

[0016] Compared with the prior art, the beneficial effects of the present application are: The off-vehicle hydraulic control system of the present application can still provide the pressure required to open the brake and the differential lock 5 for the normal driving of the vehicle through the off-vehicle control valve group 2 when the steering mechanism or the on-vehicle actuator of the vehicle is not operating, ensuring the stability and reliability of the vehicle under various working conditions.

[0017] The off-vehicle hydraulic control system of the present application provides stable pressure outputs for the differential lock 5 and the brake through the first pressure reducing valve 2-5 and the second pressure reducing valve 2-8 respectively. It is necessary to ensure that the brake and the differential lock 5 can be opened quickly and reliably, and at the same time avoid damage to the brake and the differential lock 5 caused by excessive pressure. Description of the Drawings

[0018] Figure 1 is the hydraulic schematic diagram of the off-vehicle hydraulic control system of the present application; In the figure: 1, hydraulic pump; 2, off-vehicle control valve group; 3, rear steering cylinder; 4, front steering cylinder; 5, differential lock; 6, left balance cylinder; 7, right balance cylinder; 2-1, sequence valve; 2-2 priority valve; 2-3, first relief valve; 2-4, second relief valve; 2-5, first pressure reducing valve; 2-6, differential control valve; 2-7, brake control valve; 2-8, second pressure reducing valve; 2-9, three-position five-way solenoid valve; 2-10, three-position four-way solenoid valve; 2-12, reversing valve. Detailed Embodiments

[0019] To facilitate the understanding of the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without making creative efforts shall fall within the protection scope of the present application.

[0020] As Figure 1 shown, the present application discloses an off-vehicle hydraulic control system including a hydraulic pump 1, a hydraulic oil tank, an off-vehicle control valve group 2, a steering mechanism, a differential lock 5 and a braking mechanism. Among them, the hydraulic oil tank is used to store hydraulic oil and provide the necessary oil for the entire system; the hydraulic pump 1 includes a main pump and an emergency pump connected in parallel. The main pump provides power under normal working conditions, and the emergency pump is enabled when the main pump fails to ensure the continuous operation of the system. The inlet ports of the main pump and the emergency pump are both connected to the hydraulic oil tank for extracting hydraulic oil and pressurizing and outputting it to provide high-pressure oil for the off-vehicle hydraulic control system.

[0021] Among them, the vehicle-off control valve group 2 includes a pressure reducing valve group, a brake control valve 2-7, and a differential control valve 2-6. Preferably, both the brake control valve 2-7 and the differential control valve 2-6 are two-position three-way solenoid valves. The pressure reducing valve group is connected to the oil outlet of the hydraulic pump 1 and is used to reduce the pressure of the high-pressure oil output from the hydraulic pump 1 to meet the working pressure requirements of the brake control valve 2-7 and the differential control valve 2-6. The brake control valve 2-7 is connected between the pressure reducing valve group and the braking mechanism and is responsible for controlling the action of the braking mechanism. When receiving a vehicle driving instruction, the brake control valve 2-7 will open the corresponding oil circuit, allowing the pressure-reduced hydraulic oil to flow to the braking mechanism, thereby realizing the braking release operation of the vehicle. The differential control valve 2-6 is connected between the pressure reducing valve group and the differential lock 5 and is responsible for controlling the action of the differential lock; when it is necessary to open the differential, the differential control valve 2-6 will open the corresponding oil circuit, allowing the pressure-reduced hydraulic oil to flow to the differential lock, thereby realizing the differential function of both wheels.

[0022] In some embodiments, the pressure reducing valve group includes a first pressure reducing valve 2-5 and a second pressure reducing valve 2-8. The oil inlet of the first pressure reducing valve 2-5 is connected to the oil outlet of the hydraulic pump 1, the oil outlet of the first pressure reducing valve 2-5 is connected to the oil inlet of the differential control valve 2-6, and the oil outlet of the differential control valve 2-6 is connected to the differential lock 5. The oil outlet of the first pressure reducing valve 2-5 is connected to the oil inlet of the second pressure reducing valve 2-8, the oil outlet of the second pressure reducing valve 2-8 is connected to the oil inlet of the brake control valve 2-7, and the oil outlet of the brake control valve 2-7 is connected to the braking mechanism.

[0023] In addition, the vehicle-off control valve group 2 further includes a sequence valve 2-1, a priority valve 2-2, and a steering control valve group. The oil inlet of the priority valve 2-2 is connected to the oil outlet of the hydraulic pump 1, and the priority oil outlet of the priority valve 2-2 is sequentially connected to the steering control valve group and the steering mechanism; ensuring that the steering system can obtain sufficient hydraulic oil supply to ensure the stability and response speed of the steering operation. The secondary oil outlet of the priority valve 2-2 is connected to the oil inlet of the sequence valve 2-1, the oil outlet of the sequence valve 2-1 is connected to the vehicle-on actuator, and the drain port of the sequence valve 2-1 is connected to the hydraulic oil tank.

[0024] When the steering mechanism and the upper vehicle actuating mechanism are not operating, the high-pressure oil flows from the oil outlet of the hydraulic pump 1 through the oil circuit into the P port of the lower vehicle control valve group 2. Since the steering mechanism and the upper vehicle actuating mechanism are not operating, the pressure of the high-pressure oil rises to be greater than or equal to the set pressure of the first pressure reducing valve 2-5 under the action of the sequence valve 2-1. This high-pressure oil provides a stable output of the first preset pressure through the oil outlet of the first pressure reducing valve 2-5. When the differential lock control valve 2-6 is energized, it switches to the left working state and can successfully open the differential lock 5. The high-pressure oil provides a stable output of the second preset pressure through the oil outlet of the second pressure reducing valve 2-8. When the brake control valve 2-7 is energized, it switches to the left working state and can successfully open the axle brake. The smooth driving function of the vehicle when the steering mechanism and the upper vehicle actuating mechanism are not operating is achieved.

[0025] When the upper vehicle actuating mechanism is operating, due to the increase in the load of the hydraulic system, the pressure of the high-pressure oil provided by the hydraulic pump 1 is sufficient to push the sequence valve 2-1 to the left working position. At this time, the pressure of the high-pressure oil is greater than the set pressure of the first pressure reducing valve 2-5. After the high-pressure oil is reduced in pressure by the first pressure reducing valve 2-5, it can still successfully open the axle brake and the differential lock 5 through the differential lock control valve 2-6 and the brake control valve 2-7. The combined action of the vehicle traveling and the upper vehicle actuating mechanism can be achieved.

[0026] When the lower vehicle steering mechanism is operating, due to the increase in the load of the hydraulic system, at this time, the pressure of the high-pressure oil is greater than the set pressure of the first pressure reducing valve 2-5. After the high-pressure oil is reduced in pressure by the first pressure reducing valve 2-5, it can still successfully open the axle brake and the differential lock 5 through the differential lock control valve 2-6 and the brake control valve 2-7. The combined action of the vehicle traveling and the steering mechanism can be achieved.

[0027] Therefore, regardless of whether the vehicle has a steering mechanism operation or an upper vehicle actuating mechanism operation, the sequence valve 2-1 can make the incoming oil pressure of the hydraulic pump 1 be greater than or equal to the set pressure of the first pressure reducing valve 2-5. At this time, the oil outlet of the first pressure reducing valve 2-5 provides a stable output of the first preset pressure. Thus, the axle brake and the differential lock 5 are successfully opened through the differential lock control valve 2-6 and the brake control valve 2-7 to meet the normal driving requirements of the vehicle. Preferably, the sequence valve 2-1 in this embodiment utilizes the internal control and external leakage principle. Another function of it is that when the upper vehicle actuating mechanism is operating, the pressure to open the sequence valve 2-1 will not increase to the maximum load, that is, when the upper vehicle actuating mechanism is operating, the load pressure of the upper vehicle actuating mechanism is higher than the set value of the sequence valve 2-1, and there is no need to provide additional pressure to open the sequence valve 2-1, which is beneficial to improving the energy-saving effect of the hydraulic system. Compared with the check valve or other valves that can generate back pressure in other embodiments, opening these valves will still generate additional pressure consumption, which will further reduce the energy-saving effect of the hydraulic system.

[0028] Among them, the set pressures of the first pressure reducing valve 2-5 and the second pressure reducing valve 2-8 can be flexibly set according to the opening pressures set for the brake and the differential lock 5. In this embodiment, the set opening pressure of the differential lock 5 is 40 bar, so the set pressure of the first pressure reducing valve 2-5 is 40 bar; the set opening pressure of the brake is 25 bar, so the set pressure of the second pressure reducing valve 2-8 is 25 bar. The first pressure reducing valve 2-5 and the second pressure reducing valve 2-8 respectively provide stable pressure outputs for the brake and the differential lock 5, ensuring that the brake and the differential lock 5 can be quickly and reliably opened while avoiding damage to the brake and the differential lock 5 caused by excessive pressure.

[0029] The lower vehicle hydraulic control system of this embodiment realizes that when there is no action in the vehicle steering mechanism or the upper vehicle actuator, it can still provide the pressure required to open the brake and the differential lock 5 for the normal driving of the vehicle, ensuring the stability and reliability of the vehicle under various working conditions.

[0030] In some embodiments, the lower vehicle control valve group 2 further includes a main relief valve 2-3 and a low-pressure relief valve 2-4. The oil inlet of the main relief valve 2-3 is connected to the oil outlet of the hydraulic pump 1, and the oil drain port of the main relief valve 2-3 is connected to the hydraulic oil tank. The oil inlet of the low-pressure relief valve 2-4 is connected to the oil outlet of the first pressure reducing valve 2-5, and the oil drain port of the low-pressure relief valve 2-4 is connected to the hydraulic oil tank.

[0031] In some embodiments, the steering mechanism includes a rear steering cylinder 3 and a front steering cylinder 4. The steering control valve includes a three-position five-way solenoid valve 2-9 and a three-position four-way solenoid valve 2-10. The three-position five-way solenoid valve 2-9, the front steering cylinder 4, the three-position four-way solenoid valve 2-10, and the rear steering cylinder 3 are connected in sequence, and the three-position five-way solenoid valve 2-9 is connected to the three-position four-way solenoid valve 2-10. When the Y2a of the three-position five-way solenoid valve 2-9 is energized and works in the left position (or the Y2b of the solenoid valve 2-9 is energized and works in the right position), high-pressure oil enters the front steering cylinder 4 to realize the left turn (or right turn) of the vehicle front wheels; when both the three-position five-way solenoid valve 2-9 and the three-position four-way solenoid valve 2-10 are energized, high-pressure oil can enter the front steering cylinder 4 and the rear steering cylinder 3 simultaneously, thereby realizing the four-wheel steering action of the vehicle.

[0032] In some embodiments, the steering control valve includes a reversing valve 2-12, which is connected between the front steering cylinder 4 and the three-position four-way solenoid valve 2-10, and the reversing valve 2-12 is connected to the hydraulic oil tank. Preferably, the reversing valve 2-12 is a zero-leakage two-position three-way solenoid valve. When rear-wheel steering is required, the zero-leakage two-position three-way solenoid valve 2-12 is energized and switched to the upper working position, and at the same time, the three-position five-way solenoid valve Y2b is energized and works in the right position. At this time, when Y1a of the three-position four-way solenoid valve 2-10 is energized, the rear wheels can be pushed by the steering cylinder 3 behind the axle to deflect the wheels to the left, realizing right rear-wheel steering; when Y1b of the three-position four-way solenoid valve 2-10 is energized, the rear wheels can be pushed by the steering cylinder 3 behind the axle to deflect the wheels to the right, realizing left rear-wheel steering.

[0033] In some embodiments, the lower vehicle hydraulic control system further includes a left balance cylinder 6 and a right balance cylinder 7, and both the left balance cylinder 6 and the right balance cylinder 7 are connected to the oil outlet of the first pressure reducing valve 2-5.

[0034] In some embodiments, pressure measuring devices are connected to the oil outlet of the hydraulic pump 1 and the oil outlet of the first pressure reducing valve 2-5.

[0035] This application also provides an aerial work platform, including the above-mentioned lower vehicle hydraulic control system.

[0036] The above-described embodiments merely represent several implementation manners of the present invention. The description is relatively specific and detailed, but it should not be construed as a limitation on the scope of the patent for the present invention. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several deformations and improvements can still be made, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent for the present invention shall be subject to the appended claims.

Claims

1. A hydraulic control system for getting off a vehicle, characterized in that: It comprises a hydraulic pump (1), a hydraulic oil tank, a vehicle disembarking control valve group (2), a steering mechanism, a differential lock (5) and a braking mechanism; The vehicle disembarking control valve group (2) comprises a pressure reducing valve group, a brake control valve (2-7) and a differential control valve (2-6); the pressure reducing valve group is connected to the oil outlet of the hydraulic pump (1); the brake mechanism is connected to the pressure reducing valve group via the brake control valve (2-7); and the differential lock (5) is connected to the pressure reducing valve group via the differential control valve (2-6); The vehicle disembarkation control valve group (2) further comprises a sequence valve (2-1), a priority valve (2-2) and a steering control valve, wherein the oil inlet of the priority valve (2-2) is connected to the oil outlet of the hydraulic pump (1), and the priority oil outlet of the priority valve (2-2) is connected to the steering control valve and the steering mechanism in sequence; The secondary oil outlet of the priority valve (2-2) is connected to the oil inlet of the sequence valve (2-1), the oil outlet of the sequence valve (2-1) is connected to the vehicle actuator, and the oil drain port of the sequence valve (2-1) is connected to the hydraulic oil tank.

2. The vehicle disembarking hydraulic control system according to claim 1, characterized in that: The pressure reducing valve group comprises a first pressure reducing valve (2-5) and a second pressure reducing valve (2-8), the oil inlet of the first pressure reducing valve (2-5) being connected to the oil outlet of the hydraulic pump (1), the oil outlet of the first pressure reducing valve (2-5) being connected to the oil inlet of the differential control valve (2-6), and the oil outlet of the differential control valve (2-6) being connected to the differential lock (5).

3. The vehicle disembarking hydraulic control system according to claim 2, characterized in that: The oil outlet of the first pressure reducing valve (2-5) is connected to the oil inlet of the second pressure reducing valve (2-8), the oil outlet of the secondary pressure reducing valve (2-8) is connected to the oil inlet of the brake control valve (2-7), and the oil outlet of the brake control valve (2-7) is connected to the brake mechanism.

4. The principle and control method of the vehicle getting off control valve according to claim 2, characterized in that: The vehicle disembarkation control valve group (2) further comprises a first overflow valve (2-3), the oil inlet of the first overflow valve (2-3) being connected to the oil outlet of the hydraulic pump (1), and the oil discharge port of the first overflow valve (2-3) being connected to the hydraulic oil tank.

5. The vehicle disembarking hydraulic control system according to claim 4, characterized in that: The vehicle disembarkation control valve group (2) further comprises a second overflow valve (2-4), the oil inlet of the second overflow valve (2-4) being connected to the oil outlet of the first pressure reducing valve (2-5), and the oil outlet of the second overflow valve (2-4) being connected to the hydraulic oil tank.

6. The vehicle disembarking hydraulic control system according to claim 1, characterized in that: The steering mechanism comprises a rear steering cylinder (3) and a front steering cylinder (4); the steering control valve comprises a three-position five-way solenoid valve (2-9) and a three-position four-way solenoid valve (2-10); the three-position five-way solenoid valve (2-9), the front steering cylinder (4), the three-position four-way solenoid valve (2-10) and the rear steering cylinder (3) are connected in sequence; the three-position five-way solenoid valve (2-9) is connected to the three-position four-way solenoid valve (2-10).

7. The vehicle-getting-off hydraulic control system according to claim 6, characterized in that: The steering control valve also includes a reversing valve (2-12), which is connected between the front steering cylinder 4 and the three-position four-way solenoid valve (2-10), and the reversing valve (2-12) is connected to the hydraulic oil tank.

8. The vehicle disembarking hydraulic control system according to claim 2, characterized in that: The vehicle disembarking hydraulic control system further comprises a left balancing oil cylinder (6) and a right balancing oil cylinder (7), and both the left balancing oil cylinder (6) and the right balancing oil cylinder (7) are connected to the oil outlet of the first pressure reducing valve (2-5).

9. The vehicle disembarking hydraulic control system according to claim 2, characterized in that: The oil outlet of the hydraulic pump (1) and the oil outlet of the first pressure reducing valve (2-5) are both connected to a pressure measuring device.

10. An aerial work platform, characterized in that: It comprises the vehicle getting off hydraulic control system as described in any one of claims 1-9.

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