Hydraulic control system and control method for a suspension cylinder

Abstract

The present application provides a kind of hydraulic control system of suspension oil cylinder, including suspension oil cylinder, balance valve and multi-way valve group;And suspension control valve group, wherein, suspension control valve group includes first control reversing valve and second control reversing valve;The working oil port of first control reversing valve is connected between reversing valve and the first main oil path of balance valve, and the oil return port of first control reversing valve is communicated with first oil tank;The working oil port of second control reversing valve is connected with the second main oil path of reversing valve and balance valve, and the oil return port of second control reversing valve is communicated with first oil tank;By setting the cooperation of reversing valve, balance valve, first control reversing valve, second control reversing valve and throttle valve, when suspension oil cylinder pressure maintaining state, corresponding suspension oil cylinder is realized with the load opening of balance valve connected therewith closed, second control reversing valve working oil port closed and the triple protection of throttle valve, guarantee the stable performance of suspension oil cylinder work.

Description

Technical Field

[0001] This invention relates to the field of suspension cylinders, and in particular to a hydraulic control system and control method for suspension cylinders. Background Technology

[0002] For wheeled, support-equipped engineering vehicles, such as U-shaped slag trucks, the suspension cylinders are generally responsible for adjusting the height of the suspension frame or leveling the vehicle body. In many applications, because the lifting and lowering action of the suspension cylinders is relative to the hydraulic lines, the outlet of the suspension cylinders must be connected with a flexible hose. However, the protective layer of the hose is made of natural rubber or synthetic polymer materials, which will age and crack after a period of time under the influence of ultraviolet light and oxygen. Water will seep in and corrode the pressure-bearing steel wire mesh, reducing the hose's pressure resistance. Even metal pipes, although not showing signs of aging, can still be damaged due to fatigue or other impacts. If the pipe connected to the outlet of the suspension cylinder bursts, the load will drop uncontrollably, leading to serious consequences in many situations.

[0003] To prevent load drop caused by pipe bursts, a hydraulic control system is urgently needed in actual production processes to ensure that the suspension cylinder can smoothly lift, maintain pressure, and lower under load. Summary of the Invention

[0004] In view of the shortcomings of the prior art described above, the technical problem to be solved by the present invention is to provide a hydraulic control system for a suspension cylinder.

[0005] This invention provides a hydraulic control system for a suspension cylinder, comprising a suspension cylinder having a rodless chamber port and a rod chamber port; a balance valve having a load port and a source port, the load port being connected to the rodless chamber port; a multi-way valve assembly including a directional valve having a first working port and a second working port, the first working port and the source port being connected by a first main oil circuit, and the second working port and the rod chamber port being connected by a second main oil circuit; and a suspension control valve assembly including a first control directional valve and a second control directional valve; the working port of the first control directional valve being connected to the first main oil circuit between the directional valve and the balance valve, and the return port of the first control directional valve being connected to a first oil tank; the working port of the second control directional valve being connected to the second main oil circuit between the directional valve and the balance valve, and the return port of the second control directional valve being connected to the first oil tank.

[0006] Preferably, the second main oil circuit is connected to the pilot control port of the balance valve.

[0007] Preferably, the suspension control valve assembly further includes a throttle valve, which is disposed on the return port pipe of the first control directional valve.

[0008] Preferably, the suspension control valve assembly further includes a relief valve, the working port of which is connected between the second control directional valve and the second main oil circuit, and the return port of which is connected to the oil tank.

[0009] A hydraulic control method for a suspension cylinder, employing the aforementioned hydraulic control system for a suspension cylinder, includes the following steps: The directional valve is switched to the lifting position, the first working port of the directional valve is opened, the working port of the first control directional valve is closed, and the second oil tank supplies hydraulic oil to the rodless chamber of the suspension cylinder via the first main oil circuit to perform the lifting operation of the suspension cylinder until completion; The directional valve is switched from the lifting position to the neutral position, and both the first and second working ports of the directional valve are closed; The working port of the first control directional valve is closed, and the working port of the second control directional valve is opened, allowing the hydraulic oil in the rod chamber of the suspension cylinder to return to the first oil tank to perform the pressure holding operation of the suspension cylinder until completion; The directional valve is switched from the neutral position to the lowering position, the first working port of the directional valve is opened, the working port of the second control directional valve is closed, and hydraulic oil is supplied to the rod chamber of the suspension cylinder via the second main oil circuit to perform the load lowering of the suspension cylinder until completion.

[0010] Preferably, during the process of lowering the suspension cylinder under load, the working port of the first control directional valve is opened, and part of the hydraulic oil returns to the oil tank through the first control directional valve.

[0011] Preferably, the suspension control valve assembly further includes a throttle valve, which is installed on the return port pipe of the first control directional valve. When the working port of the first control directional valve is opened, a portion of the hydraulic oil returns to the first oil tank via the first control directional valve and the throttle valve.

[0012] As described above, the hydraulic control system for a suspension cylinder of the present invention achieves three working conditions—lifting, pressure holding, and load lowering—by employing a first control directional valve, a second control directional valve, and the coordination of the directional valves. Specifically, in the pressure holding state of the suspension cylinder, pressure holding can be achieved by closing both the working ports of the first control valve and the directional valve; even if the first control valve is open, the flow can be throttled through the damping effect of the throttle valve, maintaining the pressure holding state for a certain period; simultaneously, the opening of the second control directional valve ensures unloading at the pilot control port of the balance valve, thereby guaranteeing the safe and reliable support of the suspension cylinder. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of a hydraulic control system for a suspension cylinder according to the present invention.

[0014] Figure 2 This is a schematic diagram of the suspension control valve group in the hydraulic control system of a suspension cylinder according to the present invention.

[0015] Explanation of reference numerals in the attached figures:

[0016] 100. Suspension cylinder; 200. Balance valve; 300. Multi-way valve assembly; 310. Directional control valve; 400. Suspension control valve assembly; 410. First control directional valve; 420. Second control directional valve; 430. Relief valve; 440. Throttle valve; 500. First main oil circuit; 600. Second main oil circuit; 700. First oil tank; 800. Second oil tank. Detailed Implementation

[0017] The following specific embodiments illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification.

[0018] It should be understood that the structures, proportions, sizes, etc., illustrated in the accompanying drawings of this specification are merely for illustrative purposes to aid those skilled in the art and are not intended to limit the scope of the invention. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in proportions, or adjustments to size, without affecting the effectiveness and purpose of the invention, should still fall within the scope of the technical content disclosed in this invention. Furthermore, the terms such as "upper," "lower," "left," "right," and "middle" used in this specification are merely for clarity and are not intended to limit the scope of the invention. Changes or adjustments to their relative relationships, without substantially altering the technical content, should also be considered within the scope of the invention.

[0019] like Figure 1-2As shown, this invention provides a hydraulic control system for a suspension cylinder, including a suspension cylinder 100, a balance valve 200, a multi-way valve assembly 300, and a suspension control valve assembly 400. The suspension cylinder 100 has a rodless chamber port and a rod chamber port. The balance valve 200 has a load port and a source port, with the load port connected to the rodless chamber port. The multi-way valve assembly 300 includes a directional valve 310, which has a first working port and a second working port. A first main oil circuit 500 connects the first working port and the source port, and a second main oil circuit 600 connects the second working port and the rod chamber port. The suspension control valve assembly 400 includes a first control directional valve 410 and a second control directional valve 420; the working port of the first control directional valve 410 is connected to the first main oil circuit 500 between the directional valve 310 and the balance valve 200, and the return port of the first control directional valve 410 is connected to the first oil tank 700; the working port of the second control directional valve 420 is connected to the second main oil circuit 600 between the directional valve 310 and the balance valve 200, and the return port of the second control directional valve 420 is connected to the first oil tank 700.

[0020] Specifically, when the suspension cylinder 100 is in the lifting condition, the reversing valve 310 switches from the neutral position to the lifting position, the working port of the first control reversing valve 410 is closed, and the first working port of the reversing valve 310 is connected to the oil source port through the first main oil circuit 500. Hydraulic oil is continuously delivered into the rodless chamber until the lifting operation of the suspension cylinder 100 is completed.

[0021] When the suspension cylinder 100 is in the pressure-holding condition, the directional valve 310 switches from the raised position to the neutral position, and both the first and second working ports of the directional valve 310 are closed. The working port of the first control directional valve 410 is closed, and the working port of the second control directional valve 420 is open. A portion of the oil overflowing or leaking from the balance valve 200 is directly discharged to the first oil tank 700 through the second control directional valve 420, effectively avoiding the impact of overflow or leakage from the balance valve 200 on its set pressure. Preferably, the balance valve 200 used in this embodiment is a non-unloading balance valve 200.

[0022] When the suspension cylinder 100 is in the loaded lowering condition, such as during tank truck unloading or tipping, the reversing valve 310 switches from the neutral position to the lowering position, the working port of the second control reversing valve 420 closes, and the second working port of the reversing valve 310 is connected to the rod chamber through the second main oil circuit 600, so hydraulic fluid is continuously supplied to the rod chamber. At this time, the hydraulic fluid in the rodless chamber returns to the second oil tank 800 through the first main oil circuit 500 until the loaded lowering operation of the suspension cylinder 100 is completed.

[0023] This suspension cylinder hydraulic control system, through the cooperation of the first control directional valve 410, the second control directional valve 420, and the directional valve 310, achieves three working conditions for the suspension cylinder 100: lifting, pressure holding, and load lowering. Specifically, in the pressure holding state of the suspension cylinder, pressure holding can be achieved by closing both the working ports of the first control valve and the directional valve; even if the first control valve is open, the flow can be throttled through the damping effect of the throttle valve, maintaining the pressure holding state for a certain period; simultaneously, the opening of the second control directional valve ensures the unloading of the balance valve pilot control port, thereby guaranteeing the safe and reliable support of the suspension cylinder.

[0024] Preferably, the balance valve 200 used in this embodiment is a non-unloading pilot balance valve 200, and the pilot control port of the balance valve 200 is connected to the working oil port of the second control directional valve 420 through the second main oil circuit 600.

[0025] When the suspension cylinder 100 is holding pressure, the working port of the second control directional valve 420 opens, the pilot control port of the balance valve 200 is depressurized, the balance valve 200 is activated, the oil source port is closed, and the suspension cylinder 100 begins to hold pressure.

[0026] Preferably, the suspension control valve assembly 400 further includes a throttle valve 440, which is disposed on the inlet or outlet pipe of the first control directional valve 410.

[0027] Before the suspension cylinder 100 is in the loaded lowering condition, the working port of the first control directional valve 410 is opened, and part of the hydraulic oil in the rodless chamber flows back to the first oil tank 700 through the first control directional valve 410 and the throttle valve 440. This is equivalent to opening a bypass that can adjust the flow rate of the hydraulic oil when returning oil from the first main oil circuit 500, adjusting the return resistance of the balance valve 200, and enabling precise control of the movement range of the suspension cylinder 100.

[0028] Meanwhile, when the suspension cylinder 100 is in the pressure-holding state, the load port of the balance valve 200 needs to be closed. Therefore, under normal circumstances, both the working ports of the first directional control valve and the directional valve 310 need to be closed. In actual engineering, when the pressure-holding state needs to be maintained for a short period of time, due to the presence of the throttle valve 440, it is sufficient to switch the directional valve 310 to the neutral position. Similarly, due to the presence of the throttle valve 440, even if the load port of the balance valve 200 is opened and the first directional control valve is damaged, the suspension cylinder 100 can be prevented from moving too abruptly, thus improving the safety performance of the suspension cylinder 100.

[0029] In particular, in the preferred embodiment, the number of suspension cylinders 100 can be two, and the multi-way valve group 300 and the suspension control valve group 400 can also be two, connected one-to-one with the suspension cylinders 100, for controlling the independent lifting and lowering of the two suspension cylinders 100. In actual engineering, the synchronous action of the two suspension cylinders and the lifting and leveling are crucial. The return port of the first control directional valve 410 in each suspension control valve group is equipped with a throttle valve 440, that is... Figure 1 The first control directional valve 410 is equipped with throttle valves 440 at both its P port and T port.

[0030] Therefore, during the load lowering process of the suspension cylinder, the working port of the first control directional valve 410 is opened, and part of the hydraulic oil returns to the first oil tank 440 through the first control directional valve 410 and the throttle valve 440. By adjusting the damping through the throttle valve 440, the load lowering speed of the suspension cylinder is adjusted, and the outlet pressure difference of the balance valve 200 is changed, thus realizing the support and leveling function of the two suspension cylinders 100. Furthermore, the synchronous action of the two suspension cylinders is achieved through the P port and T port of the first control directional valve 410.

[0031] Preferably, the suspension control valve assembly 400 further includes a relief valve, the working port of which is connected between the second control directional valve 420 and the second main oil circuit 600, and the return port of which is connected to the oil tank.

[0032] Accordingly, the present invention also proposes an embodiment of a suspension cylinder hydraulic control method, which employs the above-mentioned suspension cylinder hydraulic control system and includes the following steps:

[0033] When the reversing valve 310 is switched to the lifting position, the first working port of the reversing valve 310 is opened, and the working port of the first control reversing valve 410 is closed. The second oil tank 800 delivers hydraulic oil to the rodless chamber of the suspension cylinder 100 through the first main oil circuit 500 to carry out the lifting operation of the suspension cylinder 100 until it is finished.

[0034] When the directional valve 310 is switched from the lifting position to the neutral position, both the first and second working ports of the directional valve 310 are closed; the working port of the first control directional valve 410 is closed, and the working port of the second control directional valve 420 is opened, the hydraulic oil in the rod chamber of the suspension cylinder 100 returns to the first oil tank 700, and the pressure holding operation of the suspension cylinder 100 is carried out until the end.

[0035] When the directional valve 310 switches from the neutral position to the lowering position, the first working port of the directional valve 310 closes the working port of the second control directional valve 420, and hydraulic oil is delivered to the rod chamber of the suspension cylinder 100 through the second main oil circuit 600 to lower the suspension cylinder 100 under load until the end.

[0036] During the process of lowering the suspension cylinder 100 under load, the working port of the first control directional valve 410 is opened, and some hydraulic oil can return to the first oil tank 700 through the first control directional valve 410 and the throttle valve 440.

[0037] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

Claims

1. A hydraulic control system for a suspension cylinder, characterized in that, include: There are two suspension cylinders (100), and each suspension cylinder (100) is provided with a rodless chamber oil port and a rod chamber oil port; There are two balance valves (200), and each balance valve (200) is provided with a load port and an oil source port; the load ports of the two balance valves are respectively connected to the rodless chamber ports of the two suspension cylinders. A multi-way valve assembly (300) includes two directional valves (310), each directional valve (310) having a first working port and a second working port. The two first working ports are connected to two oil source ports via a first main oil passage (500), and the two second working ports are connected to two rod chamber ports via a second main oil passage (600). When the directional valve (310) is in the neutral position, both the first and second working ports are closed. A suspension control valve assembly (400) includes a first control directional valve (410) and a second control directional valve (420). The two working ports of the first control directional valve (410) are connected to the oil source ports of two balance valves (200) respectively through a first main oil circuit (500), and the return port of the first control directional valve (410) is connected to a first oil tank (700). The two working ports of the second control directional valve (420) are connected to the rod chamber ports of two suspension cylinders (100) respectively through a second main oil circuit (600), and the return port of the second control directional valve (420) is connected to the first oil tank (700). The balance valve (200) is a non-unloading pilot balance valve. The second main oil circuit (600) is connected to the pilot control port of the balance valve (200). It also includes a throttle valve (440) which is installed on the return port pipe of the first control directional valve (410).

2. The hydraulic control system for a suspension cylinder according to claim 1, characterized in that, The suspension control valve assembly (400) also includes an overflow valve (430), the working port of which is connected between the second control directional valve (420) and the second main oil circuit (600), and the return port of which is connected to the first oil tank.

3. A hydraulic control method for a suspension cylinder, employing the hydraulic control system for a suspension cylinder as described in any one of claims 1-2, characterized in that, Includes the following steps: When the reversing valve (310) is switched to the lifting position, the first working port of the reversing valve (310) is opened and the working port of the first control reversing valve (410) is closed. The second oil tank (800) delivers hydraulic oil to the rodless chamber of the suspension cylinder (100) through the first main oil circuit (500) to carry out the lifting operation of the suspension cylinder (100) until the end. The directional valve (310) switches from the lifting position to the neutral position, and both the first and second working ports of the directional valve (310) are closed; the working port of the first control directional valve (410) is closed, and the working port of the second control directional valve (420) is opened, so that the hydraulic oil in the rod chamber of the suspension cylinder (100) returns to the first oil tank (700) to perform the pressure holding operation of the suspension cylinder (100) until the end; When the reversing valve (310) switches from the neutral position to the lowering position, the second working port of the reversing valve (310) opens and the working port of the second control reversing valve (420) closes. Hydraulic oil is then delivered to the rod chamber of the suspension cylinder (100) through the second main oil circuit (600) to lower the suspension cylinder (100) under load until the end.

4. The hydraulic control method for a suspension cylinder according to claim 3, characterized in that, The process includes the following steps: during the lowering of the suspension cylinder (100) under load, the working port of the first control directional valve (410) is opened, and part of the hydraulic oil returns to the first oil tank (700) through the first control directional valve (410).

5. The hydraulic control method for a suspension cylinder according to claim 4, characterized in that, The suspension control valve assembly (400) also includes a throttle valve (440), which is installed on the return port pipe of the first control directional valve (410). When the working port of the first control directional valve (410) is opened, part of the hydraulic oil returns to the first oil tank (700) via the first control directional valve (410) and the throttle valve (440).

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