CN213628285U - Hydraulic balance control loop of lifting device - Google Patents
Hydraulic balance control loop of lifting device Download PDFInfo
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- CN213628285U CN213628285U CN202022806409.6U CN202022806409U CN213628285U CN 213628285 U CN213628285 U CN 213628285U CN 202022806409 U CN202022806409 U CN 202022806409U CN 213628285 U CN213628285 U CN 213628285U
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- 239000010720 hydraulic oil Substances 0.000 description 5
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- 230000001174 ascending effect Effects 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000004364 calculation method Methods 0.000 description 1
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Abstract
一种举升装置的液压平衡控制回路，包括用于举升负载的升降缸、用于采集负载的压力的传感器、PLC控制器、外控式平衡阀、比例减压阀、换向阀；升降缸有杆腔与换向阀油口Bk之间的油路与外控式平衡阀的控制油口Xk之间有控制油路一，控制油路一上设有比例减压阀；控制油路一用于向平衡阀的控制油路的提供设定压力；PLC控制器与比例减压阀的比例放大器连接；外控式平衡阀的控制油口Xk压力Pk=(Ps‑PF)/R，PF=F/A1，其中：Ps为外控式平衡阀溢流压力，PF为负载压力，F为负载在升降缸上产生的力，A1为升降缸无杆腔面积。本实用新型能够有效地提高平衡阀的最大开启压力控制，控制平衡阀开度的最大开度，从而控制下降最大速度。
A hydraulic balance control circuit of a lifting device, comprising a lifting cylinder for lifting a load, a sensor for collecting the pressure of the load, a PLC controller, an externally controlled balance valve, a proportional pressure reducing valve, and a reversing valve; There is a control oil circuit 1 between the oil circuit between the cylinder rod cavity and the oil port Bk of the reversing valve and the control oil port Xk of the external control balance valve, and a proportional pressure reducing valve is arranged on the control oil circuit 1; the control oil circuit 1. It is used to provide the set pressure to the control oil circuit of the balance valve; the PLC controller is connected to the proportional amplifier of the proportional pressure reducing valve; the control oil port Xk pressure of the externally controlled balance valve is Pk=(Ps‑PF)/R, PF=F/A1, where: Ps is the overflow pressure of the externally controlled balance valve, PF is the load pressure, F is the force generated by the load on the lift cylinder, and A1 is the rodless cavity area of the lift cylinder. The utility model can effectively improve the maximum opening pressure control of the balance valve, control the maximum opening degree of the balance valve opening degree, and thereby control the maximum descending speed.
Description
Technical Field
The utility model relates to a hydraulic balance control circuit of lifting device.
Background
In the prior art, a balance valve is usually arranged in the lifting process of the lifting device for safety, so as to ensure that the lifting device cannot automatically descend and stop at the original position when the lifting device does not have the lifting force. The existing external control type balance valves are more, and the external control type balance valves have pilot ratios (such as 1: 3, 1:5 and the like), so that the balance valves can be opened only by small control pressure, a lifting device is lowered, and therefore, the loss of the whole system is relatively small when the lifting device is lowered. However, some problems can occur in the external control type balance valve, and in the descending process, because the opening degree of the balance valve is too large, load can appear, so that the control pressure of the external control type balance valve is large and small, the vibration in the ascending and descending process can be caused at high speed and low speed, the instant stop can occur seriously, and the equipment can be damaged for a long time. The speed of the descent of the goods loaded with different weights in the descent is obviously different, and the requirement of non-working efficiency is met.
Disclosure of Invention
The utility model aims at providing a hydraulic balance control circuit of lifting device, it can improve the biggest opening pressure (or the control pressure) control of balanced valve effectively, the maximum aperture of control balanced valve aperture to control the maximum speed that descends.
The technical scheme of the utility model is that:
a hydraulic balance control loop of a lifting device comprises a lifting cylinder for lifting a load, a sensor for acquiring the pressure of the load, a PLC (programmable logic controller) for controlling the control oil port Xk pressure Pk of an external control type balance valve according to the pressure of the load acquired by the sensor, the external control type balance valve, a proportional pressure reducing valve and a reversing valve;
a control oil way I is arranged between an oil way between a rod cavity of the lifting cylinder and an oil port Bk of the reversing valve and a control oil port Xk of the externally-controlled balance valve, and a proportional pressure reducing valve is arranged on the control oil way I; the control oil circuit I is used for providing set pressure for a control oil circuit of the balance valve; the PLC is connected with a proportional amplifier of the proportional pressure reducing valve;
the control oil port Xk pressure Pk = (Ps-PF)/R, PF = F/A1 of the externally controlled balance valve, wherein: ps is the overflow pressure of the external control type balance valve, PF is the load pressure, F is the force generated by the load on the lift cylinder, and a1 is the area of the rodless cavity of the lift cylinder.
A hydraulic balance control loop of a lifting device comprises a lifting cylinder for lifting a load, a sensor for acquiring the pressure of the load, a PLC (programmable logic controller) for controlling the control oil port Xk pressure Pk of an external control type balance valve according to the pressure of the load acquired by the sensor, the external control type balance valve, a proportional pressure reducing valve and a reversing valve;
a control oil way I is arranged between an oil way between a rod cavity of the lifting cylinder and an oil port Bk of the reversing valve and a control oil port Xk of the externally-controlled balance valve, and a proportional pressure reducing valve is arranged on the control oil way I; the control oil circuit I is used for providing set pressure for a control oil circuit of the balance valve; the PLC is connected with a proportional amplifier of the proportional pressure reducing valve;
the control port Xk pressure Pk = (Ps-PF-PB a2/a1)/R, PF = F/a1 of the externally-controlled balance valve, wherein: ps is the overflow pressure of the external control type balance valve, PF is the load pressure, F is the force generated by the load on the lift cylinder, a1 is the area of the rodless cavity of the lift cylinder, a2 is the area of the rod cavity of the oil cylinder, and PB is the pressure at the oil port Bk of the reversing valve.
And a control oil path II is also arranged between an oil path between the rod cavity of the lifting cylinder and the oil port Bk of the reversing valve and the control oil port Xk of the externally-controlled balance valve, the control oil path II is connected with the control oil path I in parallel, and a throttle valve and a one-way valve are arranged on the control oil path II and used for controlling oil pressure relief of the control oil path II, wherein the throttle valve delays the pressure relief time.
The control oil port Xk of the external control type balance valve is connected with the oil outlet of the proportional pressure reducing valve, the oil inlet Jk of the proportional pressure reducing valve is connected to an oil path between the rod cavity of the lifting cylinder and the oil port Bk of the reversing valve, the oil port Ak of the reversing valve is connected with the oil port Fk of the external control type balance valve, and the oil port Vk of the external control type balance valve is connected with the rodless cavity of the lifting cylinder.
The sensor is a tension pressure sensor which is arranged on a piston rod of the lifting cylinder.
The load is placed on the lifting platform.
The lifting platform is of a scissor-type structure and comprises an upper platform, a lower platform, a hinge rod positioned between the upper platform and the lower platform and a lifting cylinder used for driving the hinge rod to lift.
The lifting platform comprises an upper platform, a lower platform and a lifting cylinder with a piston rod perpendicular to the upper platform and the lower platform.
The utility model has the beneficial technical effects that: the utility model discloses an accurate control of proportional pressure reducing valve has lived the biggest upper limit value of balanced valve control pressure for the aperture of balanced valve can not be because of too big and sudden increase of pressure, and the sudden drop is with higher speed, causes the excessive speed or the stop of decline, and the maximum pressure value of control pressure is passed through the PLC control cabinet by the upper portion load and is opened the pressure formula according to balanced guide (the formula of various operating modes may be distinguished, but all is the pilot control pressure Pk that is confirmed by known variables such as load). Thus providing reliable control accuracy for balancing the valve pilot opening pressure. The load can be reduced at an approximate speed in different load ranges, and the method is particularly suitable for occasions with large load change. The utility model discloses still have simple structure, location accuracy, flexible operation, operation safety point, can realize automatic cycle operation.
The utility model discloses mainly avoid the decline in-process load to appear. When upper goods are put in place, load gravity acts on a tension pressure sensor on a piston rod of an oil cylinder, the tension pressure sensor transmits a borne load force signal to a PLC (programmable logic controller), the PLC calculates according to a set formula algorithm to calculate an upper limit value of required control pressure Pk of an external control type balance valve (balance valve for short), the PLC transmits the upper limit value signal of the pressure Pk to a proportional pressure reducing valve, the proportional pressure reducing valve receives the signal to set an upper limit value of the pressure Pk, so that hydraulic oil of a control oil way only is smaller than or equal to the upper limit value of the set pressure Pk after being reduced by the proportional pressure reducing valve, the maximum value of the control pressure Pk of the balance valve is correspondingly adjusted, the hydraulic oil respectively flows to a rod cavity of a lifting cylinder and the control oil way of the balance valve after the reversing valve is reversed, and the control pressure is limited by the proportional pressure reducing valve, so that the opening, the rodless cavity of the lifting cylinder can always keep a certain pressure to form back pressure, and the lifting cylinder cannot descend too fast but descends stably.
Drawings
FIG. 1 is a schematic stick diagram of an externally controlled balancing valve;
FIG. 2 is a schematic diagram of the internal structure of the externally controlled balancing valve;
FIG. 3 is a hydraulic schematic diagram of the present invention;
in fig. 1, 1 is a tension pressure sensor, 2 is a load, 3 is a lifting cylinder with a rod cavity, 4 is a lifting cylinder without a rod cavity, 5 is an external control type balance valve, 6 is a throttle valve, 7 is a check valve, 8 is a proportional pressure reducing valve, 9 is a pump pressure, 10 is a reversing valve, 11 is a PLC controller, 12 is an oil port Fk, 13 is an oil port Vk, 14 is a control oil port Xk, 15 is a proportional pressure reducing valve oil inlet Jk, 16 is a check valve, 17 is a balance valve setting spring, 18 is a reversing valve oil port Ak, 19 is a reversing valve oil port Bk, 20 is an oil cylinder, 21 is an oil cylinder piston rod, 22 is a lifting platform, 23 is an upper platform.
Detailed Description
In fig. 1-3, the external control type balance valve (referred to as a balance valve for short) generally has 3 ports, which are respectively an oil port Vk13, an oil port Fk12 and a control oil port Xk14, the oil ports Vk and Fk are main oil line ports of the balance valve, and the oil port Xk is a pilot control oil line port of the balance valve. The hydraulic oil flows from Vk → Fk or from Fk → Vk. When the hydraulic oil flows from Fk → Vk, the hydraulic oil only passes through the one-way valve 16; when the pressure is applied from Vk → Fk, the pressure of the pilot oil is controlled to overcome the force of the balance valve setting spring 17 to open the balance valve, and the pressure is applied from Vk → Fk.
R is the pilot ratio of the balance valve, which is the ratio of the area over which the control pressure acts to the area over which the load pressure acts, and is typically 1: 3, 1:5, 1:6, 1:10, etc.
Ps is the relief pressure setting of the balancing valve, which ensures that the balancing valve can take the maximum load and be closed, and the set value (typically Ps 1.3 times the pressure at maximum load) is regulated by the balancing valve setting spring 17. When the control port Xk has no pressure oil, the opening pressure of the balance valve is the set value Ps of the spring.
Pk is the pressure of the control oil port Xk of the balance valve (control pressure for short), and the opening of the pilot valve core of the balance valve can be controlled by the size of Pk, so that the flow of the balance valve Vk → Fk is controlled. When the load pressure is not considered, that is, when the pressure PF of the Vk port is 0, the pilot control pressure of the balance valve is approximately Pk = PS/R, and if the pilot ratio R is 3:1, the ratio of the control pressure Pk for opening the balance valve to the pressure for opening the valve element of the oil inlet port is approximately 1: 3, when Ps =30MPa, Pk =30/3=10 MPa.
From the above it is seen that the opening of the balancing valve has an effect on both the upper load and the control pressure.
The balance valve is put into the whole hydraulic system, the return pressure is not considered, the load pressure PF and the pilot control pressure act simultaneously, the balance valve spring setting force Ps is overcome, and according to the relationship between the force balance and the pilot ratio of the balance valve, the pilot control pressure formula of the balance valve is as follows: pk = (Ps-PF)/R, PF = F/a1
PF is load pressure;
f is the force generated by the load on the oil cylinder (which is related to the weight of the upper goods, is measured by a tension pressure sensor and is transferred to a PLC controller);
a1 is the area of the rodless cavity of the oil cylinder;
a2 is the area of the rod cavity of the oil cylinder;
¢ area ratio ¢ = a2/a 1;
pressure at PB directional valve BK;
examples are: when the pilot ratio R is 4:1, the area a1 and the set pressure Ps are unchanged, and the load force is changed, the control pressure is calculated as follows.
As shown by the calculation of the control pressure Pk = (Ps-PF)/R, when the upper load changes little, the calculated value of the control pressure Pk is between 7.58 and 8.86, and the change is not big, the maximum control pressure Pk for oil supply at the actual control oil port Xk14 is fixedly set to be 9MPa, the change of the opening degree of the balance valve is not big, and the speed requirement of the upper load reduction can be basically met; when the upper load changes greatly, the calculated value of the control pressure Pk changes from 8.86MPa to 1.92MPa, the change is large, if the maximum pressure Pk at the control oil port Xk14 is not adjustable, the maximum control pressure Pk for oil supply at the control oil port Xk14 is still 9MPa, the calculated value of the control pressure Pk actually required by the control oil port Xk14 is 1.92MPa, the difference between the two values is large, when the control pressure Pk descends, the instantaneous opening degree of the balance valve is too large, the load descends rapidly, the pressure of a rod cavity of the lifting cylinder is rapidly reduced due to the too fast descending of the load, the control oil path is connected with the rod cavity of the lifting cylinder, the control pressure Pk of the control oil path of the balance valve is reduced or closed, and the descending speed of the load is suddenly reduced or stopped. Through the analysis of the processes, when the opening of the balance valve is too large or closed, the load can be instantly and rapidly reduced and instantly stopped, so that the load is reduced and shaken, and when the opening is too small, the reduction speed is too slow, the power loss is large and the efficiency is low.
The utility model relates to a balanced valve hydraulic control circuit, after the lift platform rises to target in place, when the switching-over valve 10 stopped at the meso position, load 2 was loaded, and lift jar rodless cavity 4 produced pressure P, made lift jar piston rod bear the upper portion load, and the upper portion load was through drawing pressure sensor 1, measured the load and produced power F on the hydro-cylinder, drawn pressure sensor 1's signal and be connected with PLC controller 11, and pass to PLC controller 11 with power F; the rodless cavity 4 of the lifting cylinder is connected with a balance valve 5, a main path of the balance valve 5 is connected with a reversing valve 10, a control oil path is connected with the other path of the reversing valve 10, the control oil path is divided into two paths which are connected in parallel, one path is connected with a proportional pressure reducing valve 8, and the other path is connected with a throttle valve 6 and a one-way valve 7 in series. The PLC controller 11 is connected to the proportional amplifier of the proportional pressure reducing valve 8. The control oil port Xk14 of the external control type balance valve 5 is connected with the oil outlet of the proportional pressure reducing valve 8, the oil inlet Jk15 of the proportional pressure reducing valve 8 is connected to the oil path between the rod cavity 3 of the lifting cylinder and the oil port Bk19 of the reversing valve, the oil port Ak18 of the reversing valve is connected with the oil port Fk12 of the external control type balance valve 5, and the oil port Vk13 of the external control type balance valve 5 is connected with the rodless cavity 4 of the lifting cylinder. 9 is pump pressure, provides the oil source and generates pressure.
The utility model discloses through increasing proportional pressure reducing valve 8, drawing pressure sensor 1, PLC controller 11, form the control of one set of closed loop in hydraulic system, adjust control hydraulic fluid port Xk 14's control pressure Pk. When the upper load 2 is in place, a force F generated by the load on the lifting cylinder transmits a signal to the PLC 11 through the pull pressure sensor 1, the PLC 11 calculates a control oil port Xk14 control pressure Pk of the balance valve according to an input algorithm (Pk = (Ps-PF)/R, PF = F/A1), the balance valve with different pilot control ratios needs to perform secondary correction on the value, the value is transmitted to the pressure reduction proportional valve, after the reversing valve is reversed, pressure oil is supplied to the rod cavity 3 of the lifting cylinder through the Bk, the other path of the pressure oil is supplied to the control oil port Xk of the balance valve through the proportional pressure reduction valve, the pressure of the pressure oil is reduced to Pk through the PB after the pressure of the pressure oil is reduced by the proportional pressure reduction valve 8, and the maximum value of the Pk does not change in the descending process.
For example, with this platform minimum load force F =10000N, maximum load force F =500000N, area a1=17662.5MM, pilot ratio R =4, set pressure Ps =36MPa, calculated according to Pk = (Ps-PF)/R formula:
when F =10000N, Pk =8.86MPa is calculated, since F is the minimum load value of the platform, the control pressure value required for opening the balance valve is the maximum, and therefore according to Pk, the pressure PB at the oil port Bk19 of the reversing valve is set to be 9MPa through correction, the set value of the pressure PB at the oil port Bk19 of the reversing valve is ensured to be larger than the set value of the control pressure Pk, and after PB is set to be 9MPa, adjustment is not performed (namely the set values of different lifting loads PB are not changed).
When F =500000N and Pk =1.92MPa is calculated, the pressure PB at the oil port Bk19 of the reversing valve is still set to be 9MPa, but after the proportional pressure reducing valve receives a PLC control signal, the pressure oil passing through the proportional pressure reducing valve PB =9MPa is reduced to be the pressure oil with only 1.92MPa, namely Pk is less than or equal to 1.92MPa, and therefore the balance valve can be guaranteed not to be opened to the maximum opening degree. The proportional pressure reducing valve is therefore set to a pressure setting which is preferably only once during a descent cycle, preferably only once in the PLC controller, and no longer during descent.
In practical application, different working conditions need to be considered, and the formula needs to be corrected, but the control principle is the same. If the pressure PB at the oil port Bk19 of the reversing valve acts on the thrust and the load force generated by the rod cavity, the formula needs to be adjusted: pk = (Ps-PF-PB × a2/a1)/R, and since ¢ = a2/a1, Pk = (Ps-PF-PB × ¢)/R may be adjusted and set according to the formula in the PLC controller.
Claims (8)
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| Application Number | Priority Date | Filing Date | Title |
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| CN202022806409.6U CN213628285U (en) | 2020-11-30 | 2020-11-30 | Hydraulic balance control loop of lifting device |
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| Application Number | Priority Date | Filing Date | Title |
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| CN202022806409.6U CN213628285U (en) | 2020-11-30 | 2020-11-30 | Hydraulic balance control loop of lifting device |
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| CN213628285U true CN213628285U (en) | 2021-07-06 |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112360844A (en) * | 2020-11-30 | 2021-02-12 | 湖北江山专用汽车有限公司 | Hydraulic balance control loop of lifting device |
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- 2020-11-30 CN CN202022806409.6U patent/CN213628285U/en not_active Withdrawn - After Issue
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112360844A (en) * | 2020-11-30 | 2021-02-12 | 湖北江山专用汽车有限公司 | Hydraulic balance control loop of lifting device |
| CN112360844B (en) * | 2020-11-30 | 2024-11-01 | 湖北江山专用汽车有限公司 | Hydraulic balance control loop of lifting device |
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