WO2013056442A1

WO2013056442A1 - Luffing rebound drawback control system of hydraulic crane and automobile crane

Info

Publication number: WO2013056442A1
Application number: PCT/CN2011/081013
Authority: WO
Inventors: 詹纯新; 刘权; 杨勇; 李英智
Original assignee: 中联重科股份有限公司; 湖南中联重科专用车有限责任公司
Priority date: 2011-10-20
Filing date: 2011-10-20
Publication date: 2013-04-25

Abstract

Disclosed in the present invention is a luffing rebound drawback control system of a hydraulic crane, which comprises a first work oil line (A1) and a second work oil line(B1) connected to a rod chamber (3) of a luffing hydraulic oil cylinder. The first work oil line is connected to a rodless chamber (2) by a balance valve,wherein the balance valve is a electric liquid balance valve having a electric control valve. The electric control valve is provided in a liquid control oil line (C1) of the electric liquid balance valve and controls the liquid control oil line (C1) to open or close. The liquid control oil line is connected to an exterior control oil line or a control oil source. Also disclosed in the present invention is an automobile crane having the luffing rebound drawback control system. The opening and closing of the balance valve in the luffing rebound drawback control system is not influenced by pressure of a luffing control circuit, but directly adopts electric control which can randomly change the temporal relation between the opening and closing of the balance valve and a main valve, thereby the luffing rebound drawback caused by the drawback of the luffing control system itself of a hydraulic crane is effectively eliminated.

Description

Hydraulic crane variable amplitude rebound defect control system and truck crane

The invention relates to a hydraulic crane variable amplitude control system, in particular to a hydraulic crane variable amplitude rebound defect control system. Furthermore, the present invention relates to a truck crane having the hydraulic crane variable amplitude rebound defect control system. Background technique

The amplitude of the crane refers to the horizontal distance from the vertical line of the center of rotation of the crane to the vertical line of the center of the lifting hook. Cranes often need to change the working range during the work process to be able to expand the scope of work and adapt to various lifting conditions. The variable amplitude of hydraulic cranes (such as truck cranes) is mainly in the form of hydraulic variable amplitude, that is, the variable amplitude hydraulic cylinder is used as the variable amplitude working mechanism, and the variable amplitude hydraulic cylinder requires the corresponding variable amplitude control system for control.

The hydraulic variable amplitude form adopted by the hydraulic crane has the advantages of compact structure, light operation, stable operation and safe and reliable operation. However, in the process of its amplitude variation, a common defect is the variable amplitude rebound phenomenon, so-called variable amplitude rebound, that is, hydraulic pressure. When the crane's variable amplitude down action is about to stop, the boom amplitude will automatically rebound upwards, making the variable amplitude operation less precise.

As is well known, the variable amplitude control system of a hydraulic crane includes a variable amplitude control loop composed of an oil source, a combined control valve, a balancing valve, etc., through which the hydraulic oil is supplied to a variable amplitude hydraulic cylinder as a variable amplitude actuator. . The operation mode of the combined control valve (ie, the main valve) is generally divided into an electric control type, a manual type, and a hydraulic control type, and is mainly used for controlling the switching of the main oil passage, so that the variable amplitude hydraulic cylinder realizes the telescopic movement. Existing hydraulic cranes, especially truck cranes, have widely used electronically operated main valves. The opening and closing of the main valves is achieved by a controller (preferably a programmable controller), which can preferably be completely controlled by programmable Control.

Figure 1 shows the hydraulic pressure of the balancing valve part of the prior art hydraulic crane luffing control system It is a balanced valve form widely used in existing hydraulic cranes, such as the hydraulic cylinder control circuit disclosed in U.S. Patent No. 6,098,647. As shown in Figure 1, the balancing valve used in the variable amplitude control system is a hydraulically controlled balancing valve YZ, wherein Al and Bl are the first and second working oil passages, A and B are working oil ports, and X is a hydraulic control interface. The working oil source (generally a hydraulic pump) is supplied with hydraulic oil supplied to one of the first and second working oil passages A1, Bl by the commutation control of the combined operating valve, and the first working oil passage A1 is balanced by the hydraulic control The valve YZ is connected to the rodless chamber 2, and the second working oil passage B1 is connected to the rod chamber 3. When the first working oil passage A1 enters the oil through the reversing control of the main valve, the second working oil passage B1 returns to the oil. Or when the second working oil passage B1 enters the oil, the first working oil passage A1 returns to the oil, thereby realizing the telescopic operation of the variable amplitude cylinder. That is to say, when the variable amplitude is lowered, the hydraulic oil flows in from the rod-shaped chamber 3, and the rod-free chamber 2 flows out; on the contrary, when the variable-amplitude rises, the hydraulic oil flows in from the rod-free chamber 2, and the rod chamber 3 flows out. Among them, the liquid-controlled balancing valve is a kind of balancing valve, and its function is well-known. It is mainly used to prevent the oil returning speed of the working oil passage A1 from being too fast, and to achieve a speed limiting effect, and at the same time realize self-locking when stopping the oil supply. .

It can be seen from Fig. 1 that the liquid-controlled balancing valve YZ and the main valve adopt a common mode, that is, the hydraulic control interface X is directly connected to the working oil passage B1, so that during the variable amplitude lowering operation, the liquid-controlled balance in the figure The opening of the valve depends on the pressure of the working oil passage B1, that is, when the main valve is closed and the working oil passage B1 has no pressure, the hydraulic control interface X is certainly not pressurized, and the hydraulically controlled balancing valve YZ cannot be opened. For example, in the variable amplitude control system in which the main valve is electrically controlled by the programmable controller, when the programmable controller detects the action of the operating handle, the main valve is opened, and the working oil circuit B1 establishes pressure, The hydraulic control interface X will have pressure, and the hydraulic control balance valve YZ will also open, thus achieving the variable amplitude lowering action. When the amplitude is reduced to the required amplitude, the main valve is closed after the operation handle returns to the initial position. The pressure of the oil circuit B1 is reduced to a certain value, because the pressure value of the liquid-controlled balancing valve is generally higher than the pressure of the working oil port B1 (for example, the balancing valve opening and closing pressure is 19MP, and the main valve is opened and closed). The pressure is 18MP), the hydraulically controlled balancing valve has been closed before the main valve, that is to say, in the prior art variable amplitude control system, the pressure of the hydraulically controlled balancing valve is opened or closed depending on the working oil circuit B1 Pressure, due to the main valve hydraulically controlled balancing valve opening and closing pressure The main valve is different, the closing of the hydraulically controlled balancing valve is earlier than the closing of the main valve. After the hydraulic control balance valve is closed, since the hydraulic oil pump continues to compress the hydraulic oil in the rod chamber and the rodless chamber through the main valve which is in the closing process, when the main valve returns to the neutral position, the rod cylinder of the variable amplitude cylinder is inside. The compressed hydraulic oil will return to the tank through the center of the main valve (in practical applications, the majority of the main valve of the hydraulic crane will allow the rod chamber to communicate with the tank to prevent oil accumulation in the pipeline, such as US Patent 6,6,098 , 647 ), so the pressure in the rod cavity is rapidly reduced, and the compressed hydraulic oil in the rodless chamber will release the pressure, pushing the piston rod to move up slightly, and the amplitude will rebound, causing the above-mentioned variable amplitude rebound. defect.

After the amplitude decreases, it will rebound automatically. When the rebound distance is obvious, it is l-5cm. Sometimes the distance is even further. The rebound distance depends on the system pressure. The greater the pressure, the larger the compression of the hydraulic oil, and the greater the rebound distance.

In view of the fact that most of the existing hydraulic cranes (such as truck cranes) have the above-mentioned variable amplitude rebound defect, it is necessary to improve the balance valve portion in the variable amplitude control system to provide a variable amplitude rebound defect control system, which can effectively It is used in the variable amplitude control loop of hydraulic cranes. Summary of the invention

The technical problem to be solved by the present invention is to provide a hydraulic crane variable amplitude rebound defect control system capable of effectively eliminating the variable amplitude rebound defect of the hydraulic crane.

In addition, the technical problem to be further solved by the present invention is to provide a truck crane whose variable amplitude control system can effectively reduce the amplitude rebounding defect of the crane.

In order to solve the above technical problem, the present invention provides a hydraulic crane variable amplitude rebound defect control system, including a first working oil passage and a second working oil passage connected to the variable amplitude hydraulic cylinder having a rod cavity, the first working oil passage Connected to the rodless chamber of the variable amplitude hydraulic cylinder via a balancing valve, wherein the balancing valve is an electro-hydraulic balancing valve having an electrically controlled valve, and the electrically controlled valve is disposed on a hydraulic control oil passage of the electrohydraulic balancing valve And controlling the conduction and cutting of the hydraulic control oil circuit, the liquid control oil circuit is connected to the liquid Control the oil circuit or control the oil source outside the variable control loop of the crane.

Preferably, the electric control valve is an electro-hydraulic proportional pressure valve, an electromagnetic reversing valve, an electromagnetic on-off valve or an electromagnetic proportional directional control valve.

Preferably, the oil control oil line is further provided with an oil filter and a damping valve.

Specifically, the first working oil passage is in communication with the fuel tank via the differential relief valve between the variable amplitude hydraulic cylinder and the electro-hydraulic balancing valve.

Specifically, the hydraulic control oil passage is in communication with the oil tank via a damping valve and a one-way valve.

Specifically, the first working oil passage is in communication with the spring chamber of the balancing valve unit of the electro-hydraulic balancing valve via the one-way damping valve between the variable amplitude hydraulic cylinder and the electro-hydraulic balancing valve.

Preferably, the electro-hydraulic balancing valve comprises a valve body, the valve body is provided with at least two working oil ports and a hydraulic control interface, and the electric control valve is disposed inside the valve body of the electro-hydraulic balancing valve.

In addition to the above-described hydraulic crane variable amplitude rebound defect control system, the present invention also provides a vehicle crane, wherein the automobile crane has the hydraulic crane variable amplitude rebound defect control system according to the above technical solution of the present invention.

Through the above technical solution, in the hydraulic crane variable amplitude rebound defect control system of the present invention, the opening and closing of the electro-hydraulic balancing valve are directly controlled by the electric control valve (preferably proportional solenoid valve), and the corresponding hydraulic oil circuit connection relationship is simultaneously The change is made. This electronic control mode enables the opening and closing of the electro-hydraulic balancing valve to be controlled by a controller, such as a programmable controller, so that the synchronous operation of the balancing valve and the main valve becomes possible, so that the balancing valve for the variable amplitude control is used. The opening and closing is no longer affected by the pressure of the variable amplitude control loop, but directly adopts electrical control, which can arbitrarily change the timing relationship between the balancing valve and the opening and closing of the main valve of the hydraulic system, thereby effectively eliminating the hydraulic crane variable amplitude control system. Deformation rebound defects caused by its own defects. The invention has simple structure and can be universally applied to hydraulic cranes, such as truck cranes, and has good technical application value.

Other features and advantages of the invention will be described in detail in the detailed description which follows. DRAWINGS

The following drawings are provided to provide a further understanding of the present invention, and are a part of the specification, which is used to explain the invention together with the specific embodiments described below, but the scope of the invention is not limited to the following drawings and embodiments. the way. In the drawing:

Figure 1 is a hydraulic schematic diagram of a balancing valve portion of a prior art hydraulic crane luffing control system.

Fig. 2 is a hydraulic schematic diagram of a hydraulic crane variable amplitude rebound defect control system according to an embodiment of the present invention.

Description of the reference signs:

1 electro-hydraulic balance valve; 2 rodless cavity;

3 has a rod cavity; 4 electromagnetic proportional pressure valve;

5 one-way damping valve; 6 differential pressure reducing valve;

7 balance valve unit A, B working oil port;

A1 first working oil circuit; B1 second working oil circuit;

C1 hydraulic control oil circuit; X hydraulic control interface;

YZ hydraulic control balance valve. detailed description

The specific embodiments of the present invention are described in detail below with reference to the accompanying drawings. .

First of all, it should be noted that the hydraulic crane variable amplitude rebound defect control system of the present invention belongs to the field of hydraulics. For those skilled in the art, the substantial technical idea lies in the hydraulic connection relationship, as shown in the hydraulic schematic diagram shown in FIG. The connection relationship and associated valve functions are not specific to their mechanical structure. Of course, after knowing the technical idea of the present invention, the person skilled in the art can also use the valve of the hydraulic crane variable amplitude rebound defect control system of the present invention. The electro-hydraulic balancing valve as described below is manufactured as a separate product, which in turn is connected to the variable amplitude control circuit of the hydraulic crane, thereby functioning as the variable amplitude rebound defect control system of the present invention, which is also within the scope of the present invention.

Fig. 2 is a view showing the hydraulic principle of a hydraulic crane variable amplitude rebound defect control system according to a preferred embodiment of the present invention.

Referring to FIG. 2, the hydraulic crane variable amplitude rebound defect control system of the present invention includes a first working oil passage A1 and a second working oil passage B1, wherein the first working oil passage A1 is connected to the variable amplitude hydraulic cylinder via the balancing valve. The rod chamber 2, the second working oil passage B1 is connected to the rod chamber 3 of the variable amplitude hydraulic cylinder

The above hydraulic connection relationship is a well-known connection structure of the hydraulic crane luffing control system. However, unlike the prior art, as shown in FIG. 2, the balancing valve is an electro-hydraulic balancing valve, and the electro-hydraulic balancing valve is connected with the liquid control oil. The road C1 is provided with an electromagnetic proportional pressure valve 4 (also referred to as "electro-hydraulic proportional valve" or "proportional solenoid valve" in the electric liquid balance valve), and the hydraulic control oil line is connected to The control oil circuit or control oil source outside the hydraulic crane luffing control circuit.

It should be noted that, for those skilled in the art, whether it is a conventional balancing valve, a hydraulically controlled balancing valve, or an electronically controlled balancing valve, its main function is to realize a speed limiting self-locking function, and thus variously known The balancing valve includes the basic module of the balancing valve, that is, the balancing valve unit 7 indicated in Fig. 2, which is generally formed by the parallel connection of the one-way valve and the external control sequence valve, wherein the external control interface of the external control sequence valve is used for connecting the external control oil Road, this is a conventional structure in the hydraulic field. Correspondingly, the liquid-controlled balancing valve and the electronically-controlled balancing valve mainly add their own unique control structures based on the basic module of the balancing valve. Therefore, with regard to the above-mentioned electro-hydraulic balancing valve of the present invention, whether or not it is mentioned The above-mentioned balancing valve basic module, that is, the balancing valve unit 7, is well known, and it should not affect the protection scope of the present invention.

It can be seen from the above basic technical solutions that the variable amplitude rebound defect control system of the present invention adopts a unique electro-hydraulic balancing valve in the variable amplitude hydraulic circuit, and the opening and closing of the electro-hydraulic balancing valve is no longer purely controlled by pressure, but An electromagnetic proportional pressure valve 4 is disposed on the hydraulic control oil passage C1, and the liquid The oil control passage CI is connected to the external control oil source and is no longer connected to the second working oil passage B1, so the control of the hydraulic control oil passage C1 is controlled by an electromagnetic proportional pressure valve (that is, a "proportional solenoid valve" as known to those skilled in the art). The electric control method is used to realize the on/off of the hydraulic control oil circuit C1, so that the electromagnetic proportional pressure valve can be connected to the controller through a line, for example, a programmable controller, and the balance valve and the main valve are simultaneously closed by program control, thereby Basically eliminate the phenomenon of variable amplitude rebound.

That is to say, the opening and closing of the electro-hydraulic balancing valve of the present invention is not affected by the pressure of the hydraulic system, and is completely driven by the electromagnetic force. The specific analysis is as follows. Referring to Figure 2, the balance valve and the main valve are in separate mode. The opening of the hydraulic control interface X does not depend on the pressure of the second working oil circuit B1, that is, when the main valve is closed, the second working oil After the road B1 has no pressure, the hydraulic control interface X is connected to other control oil circuits of the hydraulic system or the control oil source, and the balance valve can still be opened. Compared with the prior art sharing mode shown in FIG. 1, the opening and closing of the electrohydraulic balancing valve of the present invention does not have an interrelated relationship with the opening and closing of the main valve, which is the opening and closing of the main valve and the balancing valve. The timing adjustment of the opening and closing provides a large degree of freedom, and since the electro-hydraulic combination is adopted, the closing time of the variable-amplitude balancing valve can be adjusted to be almost simultaneously closed with the main valve as needed, for example, by a programmable controller. Therefore, the swing balancing valve is closed almost simultaneously with respect to the main valve. Therefore, unlike the prior art, the hydraulic oil cannot continue to compress the hydraulic oil in the rod chamber and the rodless chamber through the main valve. When the main valve returns to the neutral position, the rod chamber of the variable amplitude cylinder is substantially not compressed. The hydraulic oil returns to the hydraulic tank through the center of the main valve, so the phenomenon of buckling is almost impossible.

It should be noted that, in the above technical solution, the present invention uses an electro-hydraulic proportional pressure valve 4 (ie, a proportional solenoid valve) to control the on and off of the hydraulic control oil passage C1, but the present invention can obviously be replaced by other electronically controlled valves. The proportional solenoid valve can be controlled by an electronically controlled manner to control the on/off of the hydraulic control oil passage C1, such as an electromagnetic reversing valve, an electromagnetic switching valve, an electromagnetic proportional directional control valve, and the like. However, it should be noted that the use of the electro-hydraulic proportional pressure valve 4 is a preferred embodiment of the present invention, and has the advantage that the large control current of the electro-hydraulic proportional pressure valve 4 and the hydraulic control oil passage pressure can be proportionally controlled. When the control is performed by the programmable controller, the pressure of the hydraulic control oil passage can be more accurately made, so that the operation of the electro-hydraulic balance valve is more reliable. Using other When the electric control valve controls the on/off of the hydraulic control oil circuit CI, the pressure of the external control oil source or the control oil circuit is required to enable the opening and closing of the balance valve unit 7, that is, the corresponding pressure is applied to the external control oil source or the control oil passage. Claim. However, it is obvious that the electro-hydraulic balancing valve of the present invention is not limited to the form of the above proportional solenoid valve (ie, electro-hydraulic proportional pressure valve), and can be controlled by various electric control valves as long as the electric control valve can be connected to The controller can control the on/off of the hydraulic control oil circuit C1 in real time.

Based on the above basic technical solutions, as shown in Fig. 2, the oil control oil circuit C1 is further provided with an oil filter and a damping valve. The oil filter is mainly used to filter impurities that may exist in the oil control oil to prevent it from entering the electro-hydraulic balance valve and damage the valve; the damping valve is mainly used to prevent the pressure of the hydraulic control oil path from changing too fast, and to prevent impact on the system.

In addition, as a specific alternative of the balancing valve, the first working oil passage A1 communicates with the fuel tank via the differential relief valve 6 between the variable amplitude hydraulic cylinder and the electro-hydraulic balancing valve, which is mainly In the process of luffing, there is no overflow and oil returning of the rod chamber 2 under pressure. The hydraulic control oil passage C1 communicates with the oil tank via a damping valve and a one-way valve, which mainly prevents the pressure of the hydraulic control oil passage C1 from being excessively returned to the oil. In addition, the first working oil passage A1 communicates with the spring chamber of the balancing valve unit 7 of the electro-hydraulic balancing valve via the one-way damping valve 5 between the variable amplitude hydraulic cylinder and the electro-hydraulic balancing valve. It is mainly used to improve the portability of the operation of the balancing valve unit 7, so that the opening and closing of the electro-hydraulic balancing valve is more flexible, so that the return spring having a large elastic modulus can be omitted. Of course, it will be apparent to those skilled in the art that the above-described overflow measures are not necessarily employed, and other well-known forms may be employed, but these well-known modifications are not intended to depart from the scope of the present invention.

Within the scope of the above technical idea, those skilled in the art can fully think of using the technical idea of the present invention to manufacture the electro-hydraulic balancing valve of the present invention into a separate product, and then connect the electro-hydraulic balancing valve configured as a separate product to The hydraulic variable amplitude control circuit of the hydraulic crane, for example, in the hydraulic variable amplitude control circuit of the automobile crane, constitutes the variable amplitude rebound defect control system of the present invention. Therefore, as a preferred technical solution, the electro-hydraulic balancing valve includes a valve body, and the valve body is provided with at least two working oil ports A, B and a hydraulic control interface X, and the electric control valve is disposed in the electro-hydraulic valve The inside of the valve body of the balancing valve. Based on the above-described hydraulic crane variable amplitude rebound defect control system of the present invention, the present invention provides an automobile crane having the above-described hydraulic crane variable amplitude rebound defect control system. Specifically, the hydraulic slewing control circuit of the automobile crane is connected with the above-mentioned hydraulic crane variable amplitude rebound defect control system, that is, the hydraulic crane variable amplitude rebound defect control system of the present invention is connected to the combined control valve and the variable amplitude hydraulic cylinder. Meanwhile, the working oil passages A1 and B1 shown in FIG. 2 are actually a part of the two working oil passages of the hydraulic variable amplitude control circuit, which need to be continuously connected to the combined control valve and the hydraulic pump, etc., thereby causing the hydraulic pressure of the automobile crane to be changed. The amplitude control loop eliminates the drawback of variable amplitude bounce.

As can be seen from the above description, in the hydraulic crane variable amplitude rebound defect control system of the present invention, the opening and closing of the electro-hydraulic balancing valve are directly controlled by the electronically controlled valve (preferably proportional solenoid valve), and the corresponding hydraulic oil passage is simultaneously The connection relationship is changed. This electronic control mode enables the opening and closing of the electro-hydraulic balancing valve to be controlled by a controller (for example, a programmable controller), so that the synchronous operation of the balancing valve and the main valve (ie, the combined operating valve) is possible. For example, when the operating handle is returned to the initial position, the above-mentioned variable amplitude rebound phenomenon can be avoided by using the programmable controller to simultaneously close the main valve and the balancing valve. Therefore, the present invention changes the variable amplitude balancing valve from pressure control to electrical control, and at the same time, the hydraulic oil circuit is modified in a targeted manner, so that the opening and closing of the variable amplitude balancing valve is no longer affected by the pressure of the variable amplitude control circuit, and It is directly used for electrical control, which can arbitrarily change the timing relationship between the balance valve and the opening and closing of the main valve of the hydraulic system, thereby effectively eliminating the buckling rebound defect caused by the defects of the hydraulic crane luffing control system itself. The invention has simple structure and can be universally applied to hydraulic cranes, such as automobile cranes, and has good technical application value.

The preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the specific details of the above embodiments, and various simple modifications of the technical solutions of the present invention may be made within the scope of the technical idea of the present invention. These simple variations are within the scope of the invention. For example, it is also possible to cancel the one-way damping valve 5 in Fig. 2, but it is necessary to change the spring constant of the spring of the balancing valve unit 7.

In addition, it should be noted that each specific technical method described in the above specific embodiments is specifically described. In the case of no contradiction, it can be combined in any suitable way. In order to avoid unnecessary repetition, the present invention will not be further described in various possible combinations.

In addition, any combination of various embodiments of the invention may be made, as long as it does not deviate from the idea of the invention, and should also be regarded as the disclosure of the invention.

Claims

Rights request

1. A hydraulic crane variable amplitude rebound defect control system, comprising a first working oil passage (A1) and a second working oil passage (B1) connected to the variable amplitude hydraulic cylinder having a rod cavity (3), the first work The oil passage (A1) is connected to the rodless chamber (2) of the variable amplitude hydraulic cylinder via a balancing valve, wherein the balancing valve is an electro-hydraulic balancing valve (1) having an electrically controlled valve, the electric control valve setting Controlling the conduction and disconnection of the hydraulic control oil passage on the hydraulic control oil passage (C1) of the electro-hydraulic balance valve, and the hydraulic control oil passage is connected to a control oil passage or a control oil source outside the hydraulic crane variable amplitude control loop .

2. The hydraulic crane variable amplitude rebound defect control system according to claim 1, wherein the electronic control valve is an electro-hydraulic proportional pressure valve (4), an electromagnetic reversing valve, an electromagnetic switching valve or an electromagnetic proportional directional control valve.

3. The hydraulic crane variable amplitude rebound defect control system according to claim 1, wherein the liquid control oil passage (C1) is further provided with an oil filter and a damping valve.

4. The hydraulic crane variable amplitude rebound defect control system according to claim 1, wherein the first working oil passage (A1) passes between the variable amplitude hydraulic cylinder and the electro-hydraulic balancing valve via a differential overflow The flow valve (6) is in communication with the fuel tank.

The hydraulic crane variable amplitude rebound defect control system according to claim 1, wherein the hydraulic control oil passage (C1) communicates with the oil tank via a damping valve and a check valve.

6. The hydraulic crane variable amplitude rebound defect control system according to claim 1, wherein said first working oil passage (A1) is unidirectionally damped between said variable amplitude hydraulic cylinder and said electro-hydraulic balancing valve The valve (5) is in communication with the spring chamber of the balancing valve unit (7) of the electro-hydraulic balancing valve.

The hydraulic crane variable amplitude rebound defect control system according to any one of claims 1 to 6, wherein the electro-hydraulic balancing valve comprises a valve body, and the valve body is provided with at least two working oil ports (A And B) and the hydraulic control interface (X), the electric control valve is disposed inside the valve body of the electro-hydraulic balancing valve.

A vehicle crane, wherein the truck crane has the hydraulic crane variable amplitude rebound defect control system according to any one of claims 1 to 7.