An aerial work platform and its walking chassis floating oil cylinder balance valve control system

Abstract

The present invention discloses an aerial work platform and a control system for a floating oil cylinder balance valve of its walking chassis. The control system for the floating oil cylinder balance valve of the walking chassis includes: a floating oil cylinder for driving the front axle to swing; a floating balance valve for controlling the action of the floating oil cylinder; a floating control valve assembly including at least two solenoid valves arranged in series for controlling the opening and closing of the floating balance valve; and an oil supply assembly for providing pressure oil for the floating oil cylinder and the floating control valve assembly. The control system for the floating oil cylinder balance valve of the walking chassis provided by the present invention can minimize the occurrence probability of abnormal opening of the floating balance valve, avoid the situation that the whole vehicle tilts or even overturns due to the locking of the floating oil cylinder, and improve the reliability of the control system.

Description

Technical Field

[0001] The present invention relates to the technical field of hydraulic control, and more specifically, to a walking chassis floating cylinder balance valve control system. In addition, the present invention also relates to an aerial work platform including the above-mentioned walking chassis floating cylinder balance valve control system. Background Art

[0002] The chassis structure of an aerial work platform includes a front axle and a rear axle, where the front axle is a movable axle and the rear axle is a fixed axle and is integrally connected to the chassis. There is a floating cylinder on each side of the front axle. Each chamber of the floating cylinder is equipped with a balance valve. When there is pressure at the pilot control port of the balance valve, the balance valve opens, and the two chambers of the floating cylinder are connected, enabling the front axle to swing up and down with the undulation of the ground when driving on uneven roads, and at the same time, the floating cylinder freely expands and contracts with the swing of the front axle; when there is no pressure at the pilot control port of the balance valve, the balance valve closes, locking the two chambers of the floating cylinder, and the swing angle of the front axle relative to the chassis always remains in a fixed position, and the chassis loses the floating function.

[0003] During the operation of the boom, due to the reason of oil cleanliness, the spool of the floating solenoid valve connected to the pilot control port of the balance valve may get stuck, resulting in the communication between the inlet port and the outlet port of the floating control valve. The pressure oil taken from the closed-loop walking circuit will act on the pilot control port of the floating balance valve. After being amplified by the self-pilot control ratio of the balance valve, it is very likely to open the floating balance valve, causing the floating cylinder to go soft and resulting in safety accidents such as the whole vehicle tilting or even overturning.

[0004] In summary, how to provide a balance valve control system with improved reliability is an urgent problem to be solved by those skilled in the art at present. Summary of the Invention

[0005] In view of this, an object of the present invention is to provide a walking chassis floating cylinder balance valve control system. By setting the floating control valve assembly as at least two solenoid valves connected in series, in the case where one solenoid valve gets stuck and the inlet and outlet are conducted, the other solenoid valves will remain in the off state, avoiding the pressure oil acting on the floating balance valve, and maximizing the reduction of the occurrence probability of abnormal pressure at the pilot control port of the floating balance valve, thereby improving the reliability of the walking chassis floating cylinder balance valve control system.

[0006] Another object of the present invention is to provide an aerial work platform including the above-mentioned walking chassis floating cylinder balance valve control system.

[0007] To achieve the above objects, the present invention provides the following technical solutions:

[0008] A walking chassis floating cylinder balance valve control system, comprising:

[0009] A floating oil cylinder, used to drive the front axle to swing;

[0010] A floating balance valve, used to control the action of the floating oil cylinder;

[0011] A floating control valve assembly, including at least two solenoid valves arranged in series, used to control the opening and closing of the floating balance valve;

[0012] An oil supply assembly, used to provide pressurized oil for the floating oil cylinder and the floating control valve assembly;

[0013] The pilot control port of the floating balance valve is connected to the outlet of the floating control valve assembly; the oil inlet of the floating oil cylinder and the oil inlet of the floating control valve assembly are both connected to the oil supply assembly.

[0014] Preferably, the floating control valve assembly includes two solenoid valves, and the inlet of one solenoid valve is connected to the oil supply assembly, the outlet is connected to the inlet of the other solenoid valve; the outlet of the other solenoid valve is connected to the pilot control port of the floating balance valve.

[0015] Preferably, the oil return ports of the two solenoid valves are both connected to the same oil return oil circuit.

[0016] Preferably, the solenoid valves are all two-position three-way solenoid valves.

[0017] Preferably, at least one of the inlet and the outlet of the floating control valve assembly is provided with a filter.

[0018] Preferably, the oil supply assembly includes a closed-circuit travel pump and a travel motor used to form a closed-circuit travel loop with the closed-circuit travel pump, and the closed-circuit travel pump is provided with a make-up oil pump used to provide pressurized oil for the floating oil cylinder.

[0019] Preferably, the oil supply assembly further includes a relief valve used to control the outlet pressure of the make-up oil pump, and the pressure setting range of the relief valve is 2 - 3 MPa.

[0020] Preferably, the oil supply assembly further includes a shuttle valve connected to the closed-circuit travel pump, and the outlet of the shuttle valve is connected to the inlet of the floating control valve assembly.

[0021] Preferably, the floating oil cylinder includes a left front floating oil cylinder and a right front floating oil cylinder, and the floating balance valve includes a left floating balance valve used to control the action of the left front floating oil cylinder and a right floating balance valve used to control the action of the right front floating oil cylinder.

[0022] An aerial work platform, including the walking chassis floating oil cylinder balance valve control system described in any one of the above.

[0023] When using the walking chassis floating oil cylinder balance valve control system provided by the present invention, when walking on an uneven road, all the solenoid valves in the floating control valve assembly are energized, the inlet and outlet of the floating control valve assembly are conducted, and the floating balance valve can be controlled to open to control the action of the floating oil cylinder, so that the front axle swings up and down with the undulation of the ground. When there is a solenoid valve that is not energized among all the solenoid valves in the floating control valve assembly, the inlet and outlet of the floating control valve assembly are not conducted, the floating balance valve is closed, and the floating oil cylinder is in a locked state; the swing angle of the front axle relative to the chassis is always in a fixed position, and the chassis loses the floating function.

[0024] In the case of problems with the oil cleanliness, there is a possibility that the spool of the solenoid valve gets stuck. At this time, the outlet and inlet of the solenoid valve are easily conducted. Since the floating control valve assembly in the walking chassis floating oil cylinder balance valve control system provided by the present invention is provided with at least two solenoid valves connected in series, when the outlet and inlet of one solenoid valve or some solenoid valves are conducted, the other solenoid valves can still function. As long as there is a solenoid valve whose inlet and outlet are not conducted, it can be ensured that the inlet and outlet of the floating control valve assembly are not conducted, preventing the pressure oil from acting on the floating balance valve and causing the floating balance valve to open.

[0025] Compared with the prior art, the walking chassis floating oil cylinder balance valve control system provided by the present invention can reduce the occurrence probability of abnormal opening of the floating balance valve to the greatest extent, avoid the situation of the whole vehicle tilting or even overturning due to the locking of the floating oil cylinder, and improve the reliability of the control system.

[0026] In addition, the present invention also provides an aerial work platform including the above-mentioned walking chassis floating oil cylinder balance valve control system. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only the embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained according to the provided drawings.

[0028] Figure 1 It is a schematic structural diagram of a specific embodiment of the aerial work platform provided by the present invention;

[0029] Figure 2 is Figure 1 a side view of the aerial work platform;

[0030] Figure 3 It is a schematic structural diagram of a specific embodiment of the walking chassis floating oil cylinder balance valve control system provided by the present invention.

[0031] Figures 1-3 In the middle:

[0032] 01 is the front axle, 02 is the rear axle, 03 is the boom, 04 is the turntable, 05 is the swing shaft, 06 is the chassis, 1 is the solenoid valve, 2 is the filter, 3 is the left front floating oil cylinder, 4 is the right front floating oil cylinder, 5 is the left floating balance valve, 6 is the right floating balance valve, 7 is the closed-circuit travel pump, 71 is the makeup oil pump, 72 is the relief valve, 8 is the shuttle valve, and 9 is the travel motor. Specific embodiments

[0033] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0034] The core of the present invention is to provide a travel chassis floating oil cylinder balance valve control system, in which the floating control valve assembly is set as at least two solenoid valves connected in series. In the case where one or some of the solenoid valves are stuck and the inlet and outlet are conducted, as long as there is a solenoid valve whose inlet and outlet are not conducted, the pressure oil can be prevented from acting on the floating balance valve, and the probability of abnormal pressure at the pilot control port of the floating balance valve can be reduced to the greatest extent, thereby improving the reliability of the travel chassis floating oil cylinder balance valve control system. Another core of the present invention is to provide an aerial work platform including the above-mentioned travel chassis floating oil cylinder balance valve control system.

[0035] Please refer to Figures 1-3 , Figure 1 , which is a schematic structural diagram of a specific embodiment of the aerial work platform provided by the present invention; Figure 2 is Figure 1 a side view of the aerial work platform in the middle; Figure 3 is a schematic structural diagram of a specific embodiment of the travel chassis floating oil cylinder balance valve control system provided by the present invention.

[0036] The travel chassis floating oil cylinder balance valve control system provided by this specific embodiment includes: a floating oil cylinder for driving the front axle 01 to swing; a floating balance valve for controlling the action of the floating oil cylinder; a floating control valve assembly including at least two solenoid valves 1 connected in series for controlling the opening and closing of the floating balance valve; an oil supply assembly for providing pressure oil for the floating oil cylinder and the floating control valve assembly; the pilot control port of the floating balance valve is connected to the outlet of the floating control valve assembly; the inlet of the floating oil cylinder and the inlet of the floating control valve assembly are both connected to the oil supply assembly.

[0037] In the process of using the walking chassis floating oil cylinder balance valve control system provided by this specific embodiment, when walking on an uneven road, all the solenoid valves 1 in the floating control valve assembly are energized, the inlet and outlet of the floating control valve assembly are conducted, and the floating balance valve can be controlled to open to control the action of the floating oil cylinder, so that the front axle 01 swings up and down with the undulation of the ground. When there is a solenoid valve 1 that is not energized among all the solenoid valves 1 in the floating control valve assembly, the inlet and outlet of the floating control valve assembly are not conducted, the floating balance valve is closed, and the floating oil cylinder is in a locked state; the swing angle of the front axle 01 relative to the chassis 06 is always in a fixed position, and the chassis 06 loses the floating function.

[0038] In the case of problems with the oil cleanliness, there is a possibility that the spool of the solenoid valve 1 gets stuck. At this time, the outlet and inlet of the solenoid valve 1 are easily conducted. Since the floating control valve assembly in the walking chassis floating oil cylinder balance valve control system provided by this specific embodiment is provided with at least two solenoid valves 1 connected in series, when one solenoid valve 1 or some of the solenoid valves 1 are conducted between the outlet and inlet in the non-energized state, the other solenoid valves 1 can still function. As long as there is a solenoid valve 1 with the inlet and outlet not being conducted, it can ensure that the inlet and outlet of the floating control valve assembly are not conducted, avoiding the pressure oil acting on the floating balance valve and causing the floating balance valve to open.

[0039] It should be noted that in the actual use process, generally, the floating oil cylinder includes a left front floating oil cylinder 3 and a right front floating oil cylinder 4, and the floating balance valve includes a left floating balance valve 5 for controlling the action of the left front floating oil cylinder 3 and a right floating balance valve 6 for controlling the action of the right front floating oil cylinder 4.

[0040] As Figure 3 shown, the pilot control ports of the left front floating balance valve and the right front floating balance valve are both connected to the floating control valve assembly. In the use process, after the inlet and outlet of the floating control valve assembly are conducted, the pressure oil at the outlet of the floating control valve assembly acts on the pilot control ports of the left front floating balance valve and the right front floating balance valve, opening the left front floating balance valve and the right front floating balance valve to control the actions of the left front floating oil cylinder 3 and the right front floating oil cylinder 4.

[0041] Compared with the prior art, the walking chassis floating oil cylinder balance valve control system provided by this specific embodiment can maximize the probability of abnormal opening of the floating balance valve, avoid the situation of the whole vehicle tilting or even overturning due to the locking of the floating oil cylinder, reduce the probability of accidents, and improve the reliability of the control system.

[0042] On the basis of the above embodiments, the floating control valve assembly may include two of the solenoid valves 1, and the inlet of one of the solenoid valves 1 is connected to the oil supply assembly, and the outlet is connected to the inlet of the other solenoid valve 1; the outlet of the other solenoid valve 1 is connected to the pilot control port of the floating balance valve.

[0043] As Figure 3 shown, the floating control valve assembly is provided with two solenoid valves 1. Preferably, both solenoid valves 1 are two-position three-way valves. During the connection process, the oil return ports of the two solenoid valves 1 are connected to the same oil return oil circuit, and the outlet of one solenoid valve 1 is connected to the inlet of the other solenoid valve 1.

[0044] Setting two series-connected solenoid valves 1, compared with the setting of more solenoid valves 1, the control method and the connection circuit are relatively simple, and in the case where one solenoid valve 1 fails and conducts, the other solenoid valve 1 can also play a role in preventing the floating balance valve from opening.

[0045] On the basis of the above embodiments, a filter 2 may be provided at least at one of the inlet of the floating control valve assembly and the outlet of the floating control valve assembly.

[0046] Setting the filter 2 at the inlet of the floating control valve assembly can prevent impurities in the pressure oil provided by the oil source from entering the floating control valve assembly. Setting the filter 2 at the outlet of the floating control valve assembly can prevent impurities generated by the valve body from entering the floating control valve assembly along with the oil during the oil return process, further improving the filtering effect. In addition, the filter 2 at the outlet can also prevent impurities from being carried in the pressure oil entering the floating balance valve, extending the service life of the valve body in the control system.

[0047] On the basis of the above embodiments, the oil supply assembly may include a closed-circuit travel pump 7 and a travel motor 9 for forming a closed-circuit travel loop with the closed-circuit travel pump 7. The closed-circuit travel pump 7 is provided with a makeup oil pump 71 for supplying pressure oil to the floating cylinder.

[0048] As Figure 3 shown, the closed-circuit travel pump 7 and the travel motor 9 form a closed-circuit travel loop. The outlet of the makeup oil pump 71 is connected to the floating cylinder, and the makeup oil pump 71 is also provided with an oil return oil circuit for communicating with the fuel tank.

[0049] In order to control the pressure of the pressure oil output by the makeup oil pump 71, the oil supply assembly further includes a relief valve 72 for controlling the outlet pressure of the makeup oil pump 71. The pressure setting range of the relief valve 72 is 2-3 MPa. Of course, it can also be other pressure values, which are specifically determined according to the actual situation.

[0050] Preferably, the relief valve 72 is provided with an oil return oil circuit for communicating with the fuel tank.

[0051] The oil supply assembly further includes a shuttle valve 8 connected to the closed-circuit travel pump 7. The outlet of the shuttle valve 8 is connected to the inlet of the floating control valve assembly, and the inlets of the shuttle valve 8 are respectively connected to the closed-circuit travel pump 7.

[0052] During use, the pressure oil provided by the closed-circuit travel pump 7 can flow to the floating control valve assembly through the shuttle valve 8. Preferably, a check valve can be provided at the inlet of the floating control valve assembly to prevent the pressure oil from flowing into other oil circuits.

[0053] In addition to the above-mentioned walking chassis floating cylinder balance valve control system, the present invention also provides an aerial work platform including the walking chassis floating cylinder balance valve control system disclosed in the above embodiments. For the structures of other parts of the aerial work platform, reference can be made to the prior art and will not be elaborated herein.

[0054] As Figure 1 、 2 shown, the aerial work platform includes a fixed rear axle 02, a swingable front axle 01, a turntable 04, a boom 03, a chassis 06, and a swing shaft 05, and a left front floating cylinder 3 and a right front floating cylinder 4 are provided on the front axle 01.

[0055] In this specification, the various embodiments are described in a progressive manner. Each embodiment focuses on the differences from other embodiments. For the same or similar parts among the various embodiments, reference can be made to each other. Any combination of all the embodiments provided by the present invention is within the protection scope of this invention and will not be elaborated herein.

[0056] The above has introduced in detail the aerial work platform and its walking chassis floating cylinder balance valve control system provided by the present invention. Specific examples are used herein to elaborate on the principle and implementation manner of the present invention. The description of the above embodiments is only used to help understand the method and its core idea of the present invention. It should be noted that for those of ordinary skill in the art in this technical field, without departing from the principle of the present invention, several improvements and modifications can be made to the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

Claims

1. A walking chassis floating oil cylinder balance valve control system, characterized in that, Comprising: A floating oil cylinder for driving the front axle (01) to swing; A floating balance valve for controlling the action of the floating oil cylinder; A floating control valve assembly including at least two solenoid valves (1) arranged in series for controlling the opening and closing of the floating balance valve; An oil supply assembly for supplying pressurized oil to the floating oil cylinder and the floating control valve assembly; The pilot control port of the floating balance valve is connected to the outlet of the floating control valve assembly; the oil inlet of the floating oil cylinder and the oil inlet of the floating control valve assembly are both connected to the oil supply assembly; The solenoid valves (1) are all two-position three-way solenoid valves; The oil supply assembly includes a closed-circuit travel pump (7) and a travel motor (9) for forming a closed-circuit travel loop with the closed-circuit travel pump (7), and the closed-circuit travel pump (7) is provided with a makeup oil pump (71) for supplying pressurized oil to the floating oil cylinder; The oil supply assembly further includes a relief valve (72) for controlling the outlet pressure of the makeup oil pump (71), and the pressure setting range of the relief valve (72) is 2 - 3 Mpa; The floating oil cylinder includes a left front floating oil cylinder (3) and a right front floating oil cylinder (4), and the floating balance valve includes a left floating balance valve (5) for controlling the action of the left front floating oil cylinder (3) and a right floating balance valve (6) for controlling the action of the right front floating oil cylinder (4).

2. The walking chassis floating oil cylinder balance valve control system according to claim 1, characterized in that, The floating control valve assembly includes two of the solenoid valves (1), and the inlet of one of the solenoid valves (1) is connected to the oil supply assembly, and the outlet is connected to the inlet of the other solenoid valve (1); the outlet of the other solenoid valve (1) is connected to the pilot control port of the floating balance valve.

3. The walking chassis floating oil cylinder balance valve control system according to claim 2, characterized in that, The oil return ports of the two solenoid valves (1) are both connected to the same oil return circuit.

4. The walking chassis floating oil cylinder balance valve control system according to claim 1, characterized in that, At least one of the inlet and the outlet of the floating control valve assembly is provided with a filter (2).

5. The walking chassis floating oil cylinder balance valve control system according to claim 1, characterized in that, The oil supply assembly further includes a shuttle valve (8) connected to the closed-circuit travel pump (7), and the outlet of the shuttle valve (8) is connected to the inlet of the floating control valve assembly.

6. An aerial work platform, characterized in that, Including the walking chassis floating oil cylinder balance valve control system according to any one of claims 1 - 5.

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