Method and device for boom vibration reduction

Abstract

The present invention discloses a method and device for boom vibration reduction, the method comprising: real-time calculation of the pressure value P required for each cylinder chamber when the boom is in static balance under the current position state and load; when the set conditions: the electromagnetic control reversing valve of the variable-length oil cylinder is in a closed state and the oil pressure of the variable-length oil cylinder is greater than P1 are met at the same time, the electro-hydraulic proportional pressure relief valve is opened, and the opening pressure of the relief valve is synchronously set to P1; when the oil pressure of the variable-length oil cylinder is stable and less than or equal to P1, the electro-hydraulic proportional pressure relief valve is closed, the relief valve is used as a stop valve, and the vibration reduction process ends; the device at least comprises a lifting boom and a variable-length oil cylinder, the variable-length oil cylinder is a hydraulic oil cylinder, one end of which is connected to the boom, a balancing valve is arranged on the variable-length oil cylinder, and overflow valves are respectively arranged on the rod chamber and the rodless chamber of the variable-length oil cylinder. The present invention is suitable for vibration reduction when the boom stops suddenly under various working conditions.

Description

Technical Field

[0001] The invention relates to a method and a device for boom vibration reduction, belonging to the technical field of fire safety. Background Art

[0002] As firefighting and rescue work becomes more frequent, firefighters have higher and higher requirements for the safety and comfort of rescue equipment. As the main equipment for high-altitude firefighting and rescue, the boom's movement speed, movement stability, stopping accuracy and stopping stability are the main indicators to measure its movement performance. The movement speed can be solved by increasing the flow of the hydraulic system, and the movement stability can be solved by the hydraulic balance valve, which is a mature technology. The stopping accuracy and stopping stability of the boom, that is, the vibration reduction performance of the boom, is a problem that most manufacturers need to solve urgently.

[0003] As we all know, as a cantilever beam structure, the faster the boom moves, the greater the shaking when it stops. If the boom movement speed is reduced, the rescue time will be prolonged, and the two are contradictory. The shaking of the boom will increase the panic of the operator and the rescued personnel, affecting their normal rescue work. Severe shaking will also make the whole vehicle unstable, resulting in a serious rollover accident.

[0004] At present, there are two common methods for boom vibration reduction. One method is to slow down and stop the movement of the boom by means of a ramp of an electrical control system. The disadvantage of this method is that if the ramp is set too long, the accuracy of the boom stop position will be too poor, and it will deviate from the required working position, and even create the risk of collision with external obstacles. If the ramp is set too short, the shaking of the boom cannot be effectively controlled, that is, the boom is still shaking after the ramp ends. Because the ramp parameters required for the boom to be set under various working conditions are different, and the ramp setting cannot be adjusted in real time according to the working state of the boom, this method has great limitations. Another method is to use a buffer cylinder. The disadvantage of this method is that the buffer cylinder can only work when the cylinder is extended or retracted to the extreme position, and does not work for the intermediate position, and the practicality is too poor. Summary of the invention

[0005] In view of the above problems existing in the prior art, an object of the present invention is to provide a method and device for boom vibration reduction which can effectively control the vibration of the boom when it stops.

[0006] To achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0007] A method for boom vibration reduction comprises the following steps:

[0008] S1) According to the data of various sensors installed on the boom, the structure and weight parameters of the boom and the oil cylinder, the pressure value P required for each chamber of the oil cylinder when the boom is in static balance under the current position state and load is calculated in real time;

[0009] S2) When the following conditions are met at the same time, the electro-hydraulic proportional pressure relief valve is opened, and the opening pressure of the relief valve is simultaneously set to P1; the conditions are:

[0010] Condition 1: The electromagnetic control reversing valve of the variable amplitude oil cylinder is in the closed state;

[0011] Condition 2: The oil pressure of the luffing cylinder is greater than P1;

[0012] S3) When the oil pressure of the variable amplitude cylinder is stable and less than or equal to P1, the electro-hydraulic proportional pressure relief valve is closed. The relief valve is used as a stop valve and the vibration reduction process ends;

[0013] The P1 is the product of P and a set safety factor, that is, P1≥P.

[0014] A device for boom vibration reduction comprises at least a lifting boom and a boom cylinder, wherein the boom cylinder is a hydraulic cylinder, one end of which is connected to the boom and is used to drive the boom to perform pitching motion; a balancing valve is provided on the boom cylinder to control the stability of the boom during the boom movement; overflow valves are respectively provided on the rod chamber and the rodless chamber of the boom cylinder, and the inlet of the overflow valve is connected to the cylinder, and the outlet of the overflow valve is connected to the hydraulic oil tank.

[0015] As a preferred solution, the relief valve is an electro-hydraulic proportional pressure control valve, and the opening pressure of the relief valve is changed by adjusting the electrical signal. The relief valve is always in a cut-off state when the power is off.

[0016] As a preferred solution, the rod chamber and the rodless chamber of the variable amplitude oil cylinder are respectively provided with sensors for measuring oil pressure.

[0017] As a preferred solution, the device is also provided with an electromagnetically controlled reversing valve.

[0018] As a preferred solution, the boom is installed with but not limited to the following sensors: a sensor for measuring the length and angle of the boom, a sensor for measuring the working load of the boom, which are used to transmit information such as the length, angle and working load of the boom in real time.

[0019] As a preferred solution, the device is also provided with a controller, which performs calculations by reading sensor data provided on the arm, determines whether the reversing valve is open according to the signal output of the electromagnetically controlled reversing valve, and further controls the electro-hydraulic proportional pressure relief valve.

[0020] Compared with the prior art, the beneficial technical effects of the present invention are:

[0021] 1. It is applicable to the working conditions when the boom stops in various working states. By accurately calculating the static equilibrium oil pressure P of the boom at various positions and loads, the opening pressure P1 of the overflow valve can be determined in real time, so that vibration reduction can be achieved when the boom stops suddenly in any moving state;

[0022] 2. Since overflow valves are installed on both the rod chamber and the rodless chamber of the boom cylinder, and the closing condition of the overflow valve is that the oil pressure is stable and less than or equal to P1, the boom vibration reduction process can continue until the vibration is eliminated, greatly shortening the number and amplitude of vibrations. By reasonably setting the safety factor of the opening pressure P1 of the overflow valve and reasonably selecting the flow of the overflow valve, the free vibration of the boom can even be converted into a deceleration process, completely eliminating the rebound phenomenon when the boom stops. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a structural schematic diagram of a commonly used climbing platform fire truck;

[0024] Figure 2 for Figure 1 Force analysis diagram of No. 2 in the middle;

[0025] Figure 3 This is a working principle diagram of the device described in the embodiment for achieving vibration reduction.

[0026] The numbers in the figure are as follows: 1. Turntable; 2. Oil pressure sensor; 3. Boom cylinder; 4. Oil pressure sensor; 5. Long angle sensor; 6. Boom bracket; 7. Controller; 8. Weighing sensor; 9. Working platform; 10. Electro-hydraulic proportional relief valve; 11. Two-phase balancing valve; 12. Electro-hydraulic proportional reversing valve; 13. Electro-hydraulic proportional relief valve; 14. One-way oil supply valve. DETAILED DESCRIPTION

[0027] The technical solution of the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments.

[0028] Example

[0029] See also Figure 1 As shown: This embodiment provides a device for boom vibration reduction, including a turntable 1, an oil pressure sensor 2, a boom cylinder 3, an oil pressure sensor 4, a long angle sensor 5, a boom 6, a controller 7, a weighing sensor 8, a working platform 9, an electro-hydraulic proportional relief valve 10, a two-phase balancing valve 11, an electro-hydraulic proportional reversing valve 12 and an electro-hydraulic proportional relief valve 13.

[0030] The turntable 1 described in this embodiment is a rotating platform connected to the lower vehicle body through a slewing bearing. A controller 7 is installed on the turntable 1 for collecting sensor signals (such as oil pressure sensor 2, oil pressure sensor 4, long angle sensor 5, weighing sensor 8) and performing analysis and calculation, and outputting control signals to actuators such as electro-hydraulic proportional relief valve 10, electro-hydraulic proportional reversing valve 12, and electro-hydraulic proportional relief valve 13 according to a predetermined program.

[0031] The luffing boom 6 described in this embodiment is a telescopic structure, one end of which is hinged to the turntable 1 and the other end is hinged to the working platform 9. The luffing boom 6 is equipped with a length angle sensor 5 for measuring the length and pitch angle of the boom in real time.

[0032] The luffing oil cylinder 3 described in this embodiment is a hydraulic oil cylinder, one end of which is hinged on the turntable 1, and the other end is hinged on the luffing boom 6. The luffing boom 6 can be driven to perform pitching motion around the turntable hinge point by the extension and contraction of the oil cylinder. An oil pressure sensor 2 and an oil pressure sensor 4 are respectively installed on the rodless chamber and the rod chamber of the luffing oil cylinder 3, which are used to measure the oil pressure of the rodless chamber and the rod chamber in real time.

[0033] The working platform 9 described in this embodiment is hinged on the luffing boom 6 and can be leveled around the hinge axis. A weighing sensor 8 is installed on the working platform 9 to measure the actual load in the platform in real time.

[0034] like Figure 3 As shown, the rodless chamber and the rod chamber of the variable-length oil cylinder 3 are respectively connected with an electro-hydraulic proportional relief valve 10 and an electro-hydraulic proportional relief valve 13. The electro-hydraulic proportional relief valve 10 and the electro-hydraulic proportional relief valve 13 can perform proportional stepless control on the opening pressure by the magnitude of the current. When the power is off, the electro-hydraulic proportional relief valve 10 and the electro-hydraulic proportional relief valve 13 become stop valves.

[0035] like Figure 3 As shown, as a common configuration, the luffing boom 6 performs a reversing action through an electro-hydraulic proportional reversing valve 12 .

[0036] like Figure 3 As shown, in order to ensure the movement stability of the luffing boom 6 and the locking reliability when stopping, a two-phase balancing valve 11 is installed on the luffing cylinder 3.

[0037] like Figure 3 As shown, a one-way oil replenishing valve 14 is provided between the outlet of the electro-hydraulic proportional relief valve 10 and the rodless chamber of the luffing cylinder 3 and between the outlet of the electro-hydraulic proportional relief valve 13 and the rod chamber of the luffing cylinder 3 .

[0038] Figure 2The triangle shown is composed of the connection hinge of the turntable 1, the variable-length oil cylinder 3, and the variable-length boom 6. The side lengths a and b of the triangle in the figure are known parameters, and the angle θ can be read by the controller 7 through the long angle sensor 5. Obviously, the self-weight of the variable-length boom 6, the actual load on the working platform, and the self-weight load can be simplified to force N and moment M around the boom variable-length hinge. Both force N and moment M can be calculated by the controller 7 through the long angle sensor 5, the weighing sensor 8, the weight and center of gravity position of each section of the variable-length boom 6, the weight and center of gravity position of the working platform, and other known or measurable parameters. The force of the cylinder is represented by F. According to the moment balance and the cosine theorem, it is not difficult to calculate:

[0039]

[0040] The measured oil pressure of the rodless chamber of the variable amplitude oil cylinder 3 is P A Indicates that the measured oil pressure of the rod cavity is P B The rodless chamber oil pressure when the boom is in the static equilibrium state at the current position is represented by P, the rodless chamber oil flow cross-sectional area of ​​the rodless chamber is represented by A, and the rod chamber oil flow cross-sectional area is represented by B.

[0041] F=PA-P B B

[0042] Combining the above two formulas, we can get:

[0043]

[0044] The method for realizing boom vibration reduction by using the above device of the present invention comprises the following steps:

[0045] The first step is to calculate in real time the oil pressure P required for the rodless chamber of the boom cylinder 3 when the boom is in a balanced state at the current position according to the data of various sensors installed on the boom;

[0046] In the second step, the controller judges that when the following conditions are met at the same time, the electro-hydraulic proportional pressure relief valve 10 and the electro-hydraulic proportional pressure relief valve 13 will be opened, and the opening pressure of the electro-hydraulic proportional pressure relief valve 10 will be set to P1, and the opening pressure of the electro-hydraulic proportional pressure relief valve 13 will be set to P2; if the safety factor is set to 1% (which can be adjusted according to actual needs), then P1 = P × 1%, P2 can be set to a fixed value as needed, and the vibration reduction process begins;

[0047] Condition 1: The electro-hydraulic proportional reversing valve 12 is in the closed state;

[0048] Condition 2: The measured oil pressure PA of the rodless chamber of the luffing cylinder 3 is greater than P1;

[0049] In the third step, when the controller detects that PA remains stable and is less than or equal to P1, it sends a signal and cuts off the power to the electro-hydraulic proportional relief valve 10 and the electro-hydraulic proportional pressure relief valve 13, and the vibration reduction process ends.

[0050] As can be seen from the above, when the vibration reduction starts, the oil in the rodless chamber of the variable-length oil cylinder 3 flows back to the oil tank through the electro-hydraulic proportional relief valve 10, and the rod chamber is replenished through the one-way oil replenishment valve 14. On the contrary, when the boom rebounds, the oil in the rod chamber flows back to the oil tank through the electro-hydraulic proportional relief valve 13, and the rodless chamber is replenished through the one-way oil replenishment valve 14. The fundamental reason for the vibration is that after the electro-hydraulic proportional reversing valve 12 is suddenly closed, the inertia of the boom and the load causes the oil pressure in the rodless chamber to deviate from the oil pressure P in the equilibrium state. Therefore, as long as the boom is not in the equilibrium state, the electro-hydraulic proportional pressure relief valve 10 or the electro-hydraulic proportional pressure relief valve 13 will continue to play a damping and vibration reduction role until the boom is in a static and stable state. Moreover, vibration reduction has nothing to do with the position and load of the boom, and is applicable to any position and state of the boom. By simply setting the safety factor of P1 reasonably, the free vibration of the boom can be converted into a deceleration process, which greatly improves the safety of the boom and the vehicle and the comfort of the personnel.

[0051] From the above, it can be seen that the present invention is suitable for reducing vibration when the boom stops suddenly under various working conditions, and can greatly shorten the number and amplitude of vibrations. Moreover, by only reasonably setting the safety factor of the opening pressure P1 of the relief valve and reasonably selecting the flow rate of the relief valve, the free vibration of the boom can be converted into a deceleration process, thereby completely eliminating the rebound phenomenon when the boom stops. Therefore, compared with the prior art, the present invention has obvious progress and practicality.

[0052] Finally, it is necessary to point out here that the above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto, and any changes or substitutions that can be easily thought of by any technician familiar with the technical field within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention.

Claims

1. A method for boom vibration reduction, the method being implemented by using a boom vibration reduction device, the boom vibration reduction device comprising a turntable (1), a first oil pressure sensor (2), a variable-length oil cylinder (3), a second oil pressure sensor (4), a long angle sensor (5), a variable-length boom (6), a controller (7), a weighing sensor (8), a working platform (9), a first electro-hydraulic proportional relief valve (10), an electro-hydraulic proportional reversing valve (12) and a second electro-hydraulic proportional relief valve (13), the turntable (1) being provided with a controller (7), the variable-length boom (6) being a telescopic structure, one end of which is hingedly connected to the turntable (1), and the other end of which is hingedly connected to the turntable (1). One end is hinged to the working platform (9); a length angle sensor (5) for measuring the length and pitch angle of the boom in real time is installed on the boom (6); one end of the boom cylinder (3) is hinged to the turntable (1), and the other end is hinged to the boom (6); a first oil pressure sensor (2) and a second oil pressure sensor (4) are installed on the rodless chamber and the rod chamber of the boom cylinder (3), respectively; a first electro-hydraulic proportional overflow valve (10) and a second electro-hydraulic proportional overflow valve (13) are connected to the rodless chamber and the rod chamber of the boom cylinder (3), respectively; a weighing sensor (8) is installed on the working platform (9); it is characterized in that, The method comprises the following steps: S1) calculates in real time the oil pressure P required for the rodless chamber of the boom cylinder (3) when the boom is in a balanced state at the current position according to the data of various sensors installed on the boom. The calculation formula is as follows: Wherein, M represents the self-weight of the luffing boom (6), the actual load on the working platform (9) and the torque of the self-weight load around the luffing hinge of the boom, and M is calculated by the controller (7) through the long angle sensor (5), the weighing sensor (8), the weight and the center of gravity position of each arm of the luffing boom (6), and the weight and the center of gravity position of the working platform (9); the turntable (1), the luffing cylinder (3) and the connecting hinge of the luffing boom (6) form a triangle, and a represents represents the length of the side formed by the connection point between the turntable (1) and the variable-length arm (6) to the connection point between the variable-length oil cylinder (3) and the variable-length arm (6); b represents the length of the side formed by the connection point between the turntable (1) and the variable-length arm (6) to the connection point between the turntable (1) and the variable-length oil cylinder (3); θ is the angle between the side length a and the side length b, which is read by the controller (7) through the length angle sensor (5); A represents the oil flow cross-sectional area of ​​the rodless cavity, B represents the oil flow cross-sectional area of ​​the rod cavity, and P B It indicates the measured oil pressure in the rod chamber; S2) the controller determines that when the following conditions are met at the same time, the first electro-hydraulic proportional relief valve (10) and the second electro-hydraulic proportional relief valve (13) are opened, and the opening pressure of the first electro-hydraulic proportional relief valve (10) is set to P1, and the opening pressure of the second electro-hydraulic proportional relief valve (13) is set to P2; P1 is the product of P and a set safety factor, that is, P1≥P, and P2 is set to a fixed value as required; the vibration reduction process begins; Condition 1: the electro-hydraulic proportional reversing valve (12) is in the closed state; Condition 2: The measured oil pressure PA of the rodless chamber of the luffing cylinder (3) is greater than P1; S3) When the controller detects that PA remains stable and is less than or equal to P1, it sends a signal and cuts off the power to the first electro-hydraulic proportional relief valve (10) and the second electro-hydraulic proportional relief valve (13), and the vibration reduction process ends.

2. The method according to claim 1, characterized in that: In the power-off state, the first electro-hydraulic proportional relief valve (10) and the second electro-hydraulic proportional relief valve (13) become stop valves.

3. The method according to claim 1, characterized in that: The luffing boom (6) performs a reversing action via an electro-hydraulic proportional reversing valve (12).

4. The method according to claim 1, characterized in that: A two-phase balancing valve (11) is installed on the luffing oil cylinder (3).

5. The method according to claim 1, characterized in that: One-way oil replenishing valves (14) are respectively provided between the outlet of the first electro-hydraulic proportional relief valve (10) and the rodless chamber of the luffing cylinder (3), and between the outlet of the second electro-hydraulic proportional relief valve (13) and the rod chamber of the luffing cylinder (3).

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