CN205446224U - Formula electricity liquid servo is directly driven to invariable backpressure - Google Patents

Abstract

The utility model provides a constant back pressure direct-drive electro-hydraulic servo system, comprising: a controller, a driver, a servo motor, a bidirectional quantitative pump and an asymmetric hydraulic cylinder, the controller, the driver and the servo motor are connected in sequence, the control The servo motor controls the operation of the servo motor through the driver, the servo motor, the bidirectional quantitative pump and the asymmetric hydraulic cylinder are connected in sequence, and the servo motor realizes the motion control of the asymmetric hydraulic cylinder by controlling the output flow and direction of the bidirectional quantitative pump . The utility model is suitable for the control of asymmetrical hydraulic cylinders with vertical or non-horizontal installation structures. It not only completely solves the problem of unbalanced flow of asymmetrical hydraulic cylinders and the problem of sudden pressure changes during reversing, but also satisfies the control accuracy and response characteristics of the system. Under the premise, the loop cost can be greatly reduced and the control scheme can be simplified.

Description

Constant back pressure direct drive electro-hydraulic servo system

technical field

The utility model belongs to the technical field of servo control, in particular to a constant back pressure direct drive electro-hydraulic servo system.

Background technique

Due to its fast response, high control precision, good stability, and easy automatic control, the electro-hydraulic servo system was first applied to the aviation and military fields, and then gradually entered the industrial and civilian fields. At present, it has been widely used in metallurgy, engineering machinery, military industry, aviation, shipbuilding, chemical industry and other industries. Most of the core components of traditional electro-hydraulic servo systems use electro-hydraulic servo valves. Their prominent disadvantages are high maintenance and operation requirements and high energy consumption. Especially electro-hydraulic servo valves have high requirements for oil cleanliness and poor anti-pollution ability. With the rapid development of microelectronics technology and AC variable frequency speed regulation technology, coupled with breakthroughs in servo motor materials, structure and control theory, the response characteristics and control accuracy of servo motors have been greatly improved, and a new type of servo motor has emerged. The servo drive method is the direct drive electro-hydraulic servo system.

At present, a typical direct-drive electro-hydraulic servo system uses a servo motor to drive a two-way quantitative pump. The output flow and direction of the two-way pump are changed by changing the speed and direction of the servo motor, and the system pressure is controlled by controlling the torque of the servo motor. The mechanism's three functions of reversing, speed regulation and pressure regulation are directly controlled by the servo motor and do not require conventional electro-hydraulic servo valves, thus greatly reducing the requirements for oil cleanliness. Compared with the traditional electro-hydraulic servo system, the direct-drive electro-hydraulic servo system has multiple advantages of flexible control of servo motor transmission, low energy consumption of electric transmission and large output of hydraulic transmission.

The actuator driving mechanism of the electro-hydraulic servo system usually adopts hydraulic cylinder and hydraulic motor. Because the single-rod asymmetric hydraulic cylinder has the advantages of simple structure, less space occupation and large output, it has become a more commonly used actuator. In some Occasions must even use a single rod asymmetrical hydraulic cylinder. However, because the asymmetric hydraulic cylinder is prone to sudden pressure changes and different flow rates in the forward and reverse directions, the control effect is greatly affected.

However, the current direct-drive electro-hydraulic servo system controls the asymmetric hydraulic cylinder using the dual-pump control principle to solve the problem of flow imbalance. The implementation of the dual-pump control principle is to use two pumps to control the two chambers of the asymmetric hydraulic cylinder respectively, the large displacement pump controls the rodless chamber, and the small displacement pump controls the rod chamber. Although this solution solves the problem of unbalanced flow, the problem of sudden change in pressure when the asymmetric hydraulic cylinder changes direction still exists. In addition, the use of two pumps not only increases the cost of the system circuit, but is also not cost-effective.

Utility model content

In view of the shortcomings of the prior art described above, the purpose of this utility model is to provide a constant back pressure direct-drive electro-hydraulic servo system, which is used to solve the problem of unbalanced flow of asymmetric hydraulic cylinders and the problem of reversing in the prior art. Sudden pressure problem.

In order to achieve the above purpose and other related purposes, the utility model provides a constant back pressure direct-drive electro-hydraulic servo system, including:

A controller, a driver, a servo motor, a bidirectional quantitative pump and an asymmetrical hydraulic cylinder, the controller, the driver and the servo motor are connected in sequence, the controller controls the operation of the servo motor through the driver, the servo motor, the bidirectional quantitative The pump is sequentially connected with the asymmetric hydraulic cylinder, and the servo motor realizes the motion control of the asymmetric hydraulic cylinder by controlling the output flow and direction of the bidirectional quantitative pump.

Preferably, it also includes a constant pressure accumulator and a conventional accumulator, the constant pressure accumulator communicates with the rod cavity of the asymmetric hydraulic cylinder, and the conventional accumulator communicates with the bidirectional quantitative pump respectively. The first oil port, the second oil port.

Preferably, the third oil port of the bidirectional quantitative pump communicates with the rodless chamber of the asymmetric hydraulic cylinder.

Preferably, an electromagnetic cut-off valve is provided between the rodless cavity of the asymmetric hydraulic cylinder and the rod cavity of the asymmetric hydraulic cylinder.

Preferably, it also includes a first safety valve and a second safety valve, the first safety valve communicates with the second safety valve in reverse, and is connected to both ends of the electromagnetic cut-off valve.

Preferably, an electromagnetic ball valve is further included, the oil inlet and the oil outlet of the electromagnetic ball valve are respectively connected to the third oil port of the bidirectional quantitative pump and the rodless chamber of the asymmetrical hydraulic cylinder.

Preferably, it also includes a first one-way valve and a second one-way valve, the oil inlet and the oil outlet of the first one-way valve are respectively connected to the second and third oil ports of the bidirectional quantitative pump, and their The oil outlet is connected in the same direction as the electromagnetic ball valve; the oil inlet of the second one-way valve is connected between the first safety valve and the second safety valve, and its oil outlet is connected to the bidirectional quantitative pump between the first and second oil ports.

Preferably, the constant pressure accumulator and the conventional accumulator are respectively provided with pressure sensors of the oil collection circuit.

Preferably, the asymmetric hydraulic cylinder is provided with a displacement sensor for collecting the telescopic displacement of its piston rod.

Preferably, the output end of the piston rod of the asymmetric hydraulic cylinder is connected with a load.

As mentioned above, the constant back pressure direct drive electro-hydraulic servo system of the present invention has the following beneficial effects:

The utility model adopts the principle of constant back pressure and single chamber control, and uses one pump to realize the motion control of the asymmetric hydraulic cylinder, which not only solves the problem of unbalanced flow of the asymmetric hydraulic cylinder, but also greatly reduces the cost of the circuit, and at the same time, simplifies the control program, reducing the difficulty of control;

A constant pressure accumulator is used to control the back pressure chamber of the asymmetric hydraulic cylinder, so that the pressure of the back pressure chamber remains basically constant when the hydraulic cylinder changes direction, so that there will be no sudden change in pressure during the direction change, and it provides the pressure control of the rodless chamber. favorable conditions;

The utility model is especially suitable for the control of asymmetrical hydraulic cylinders with vertical or non-horizontal installation structures. Due to the existence of gravity load in such working conditions, the pressure of the back pressure accumulator can be reduced and the system efficiency can be improved.

Description of drawings

Fig. 1 is a schematic structural diagram of a constant back pressure direct-drive electro-hydraulic servo system of the present invention.

Component label description:

1 servo motor

2 two-way quantitative pump

3 first check valve

4 second one-way valve

5 first pressure sensor

6 conventional accumulators

7 Solenoid ball valve

8 first safety valve

9 second safety valve

10 constant pressure accumulator

11 Second pressure sensor

12 Electromagnetic cut-off valve

13 Third pressure sensor

14 displacement sensor

15 asymmetrical hydraulic cylinders

16 load

17 controllers

18 drives

detailed description

The implementation of the present utility model is described below through specific examples, and those skilled in the art can easily understand other advantages and effects of the present utility model from the content disclosed in this specification. The utility model can also be implemented or applied through other different specific implementation modes, and the details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the utility model. It should be noted that, in the case of no conflict, the following embodiments and features in the embodiments can be combined with each other.

It should be noted that the diagrams provided in the following embodiments are only schematically illustrating the basic idea of the utility model, and only the components related to the utility model are shown in the diagrams rather than the number of components, Shape and size drawing, the type, quantity and proportion of each component can be changed arbitrarily during actual implementation, and the component layout type may also be more complicated.

Please refer to Figure 1, the utility model provides a schematic structural diagram of a constant back pressure direct-drive electro-hydraulic servo system, including:

A controller 17, a driver 18, a servo motor 1, a two-way quantitative pump 2 and an asymmetric hydraulic cylinder 15, the controller 17, a driver 18 are connected to the servo motor 1 in sequence, and the controller 17 controls the servo through the driver 18 The motor 1 is running, and the servo motor 1 and the bidirectional quantitative pump 2 are connected to the asymmetric hydraulic cylinder 15 in sequence. The servo motor 1 realizes the motion control of the asymmetric hydraulic cylinder 15 by controlling the output flow and direction of the bidirectional quantitative pump 2 .

It also includes a constant pressure accumulator 10 and a conventional accumulator 6, the constant pressure accumulator 10 communicates with the rod cavity of the asymmetric hydraulic cylinder 15, and the conventional accumulator 6 is connected to the two-way quantitative The first oil port and the second oil port of the pump 2 are connected, and the third oil port of the bidirectional quantitative pump 2 is connected to the rodless chamber of the asymmetric hydraulic cylinder 15, wherein the first oil port of the bidirectional quantitative pump 2 is B port, the third oil port of the bidirectional quantitative pump 2 is A port, the forward rotation of the servo motor 1 drives the 2A port of the bidirectional quantitative pump to discharge oil, and the B port sucks oil; the reverse rotation of the servo motor 1 drives the 2B port of the bidirectional quantitative pump to discharge oil, Port A absorbs oil.

Specifically, an electromagnetic cut-off valve 12 is provided between the rodless chamber of the asymmetric hydraulic cylinder 15 and the rod chamber of the asymmetric hydraulic cylinder 15. Under normal circumstances, the electromagnetic cut-off valve 12 cuts off the The connection between the rod chamber and the rodless chamber is connected to the rod chamber and the rodless chamber of the asymmetric hydraulic cylinder 15 when it is energized by the controller 17 .

Specifically, it also includes a first safety valve 8 and a second safety valve 9 , the first safety valve 8 communicates with the second safety valve 9 in reverse, and is connected to both ends of the electromagnetic shut-off valve 12 . The oil inlet and oil outlet of the electromagnetic ball valve 7 are respectively connected to the third oil port of the bidirectional quantitative pump 2 and the rodless chamber of the asymmetric hydraulic cylinder 15, wherein whether the electromagnetic ball valve 7 is powered or not Controlled by the controller 17, the above-mentioned safety valve prevents the two-cavity overpressure of the asymmetric hydraulic cylinder 15; the electromagnetic ball valve 7 is energized in a normal state to make the oil circuit conduction, and locks the current position of the asymmetric hydraulic cylinder 15 in a power-off state, which can The stop function of the asymmetrical hydraulic cylinder 15 is realized.

Preferably, a first one-way valve 3 and a second one-way valve 4 are also included, and the oil inlet and the oil outlet of the first one-way valve 3 are connected to the second and third oil ports of the bidirectional quantitative pump 2 respectively. and its oil outlet is connected in the same direction as the electromagnetic ball valve 7; the oil inlet of the second check valve 4 is connected between the first safety valve 8 and the second safety valve 9, and its oil outlet port is connected between the first and second oil ports of the bidirectional quantitative pump 2, the first one-way valve 3 realizes the oil supply function of the rodless cavity of the asymmetric hydraulic cylinder 15; the second one-way valve 4 isolates the two-way quantitative pump 2A The pressure interference between the port and the rodless cavity of the asymmetric hydraulic cylinder 15.

Preferably, the constant pressure accumulator 10 and the conventional accumulator 6 are respectively provided with a pressure sensor for collecting the oil circuit, and the electromagnetic cut-off valve 12 is also provided with a pressure sensor for collecting its oil pressure. The rod cavity of the symmetrical hydraulic cylinder 15 is connected with a displacement sensor 14 that collects the telescopic displacement of the piston rod, and the output end of the piston rod of the asymmetric hydraulic cylinder 15 is connected with a load 16, the two-way quantitative pump 2B port and the asymmetric hydraulic cylinder 15 The two chambers (rod chamber and rodless chamber) are respectively provided with a first pressure sensor 5, a second pressure sensor 11, and a third pressure sensor 13 to monitor pressure changes in real time; the displacement sensor 14 transmits the collected telescopic displacement parameters To the controller 17, the pressure sensor transmits the collected oil circuit pressure parameters to the controller 17.

Embodiment 1, the asymmetrical hydraulic cylinder 15 piston rod stretches out the action process:

The controller 17 accepts external commands, and sends a displacement extension command to the driver 18. The driver 18 drives the servo motor 1 to rotate in the forward direction. The servo motor 1 drives the two-way quantitative pump 2 to output oil at the A port and absorb oil at the B port. The conventional accumulator 6 provides two-way Quantitative pump 2B port suction flow, electromagnetic ball valve 7 is electrically connected, the pressure oil at port 2A of the two-way quantitative pump enters the rodless chamber of the asymmetric hydraulic cylinder 15; at the same time, the electromagnetic cut-off valve 12 is not powered, and the rod chamber of the asymmetric hydraulic cylinder 15 is The constant pressure accumulator 10 absorbs the oil discharged from the rod chamber of the asymmetric hydraulic cylinder 15 and maintains a certain pressure; because the force generated by the rod chamber of the asymmetric hydraulic cylinder 15 is smaller than the force generated by the rodless chamber, and when the force of the two chambers When the difference is greater than the load, the piston rod of the asymmetric hydraulic cylinder 15 stretches out; the displacement sensor 14 on the asymmetric hydraulic cylinder 15 detects the protruding displacement of the piston rod in real time and sends it to the controller 17; The actual displacement is compared, and the difference is corrected by an algorithm to output a revised displacement command to the driver 18, so as to realize the closed-loop control of the position of the asymmetric hydraulic cylinder 15 and accurately reach the expected extension position.

Embodiment 2, the process of retracting the piston rod of the asymmetrical hydraulic cylinder 15:

The controller 17 accepts external instructions, and sends a displacement retraction instruction to the driver 18. The driver 18 drives the servo motor 1 to rotate in the reverse direction. The servo motor 1 drives the two-way quantitative pump 2 to output oil at the B port and to absorb oil at the A port. The conventional accumulator 6 absorbs the bidirectional Quantitative pump 2B port oil flow, electromagnetic ball valve 7 is electrically connected, bidirectional quantitative pump 2A port absorbs the oil in the rodless chamber of asymmetric hydraulic cylinder 15, thereby reducing the pressure in the rodless chamber of asymmetric hydraulic cylinder 15; The cut-off valve 12 is not powered, and the rod cavity of the asymmetric hydraulic cylinder 15 is provided by the constant pressure accumulator 10 to provide the oil sucked by the rod cavity of the asymmetric hydraulic cylinder 15 and maintain a certain pressure; The force superimposed on the load force is greater than the force produced by the rodless cavity, and the piston rod of the asymmetric hydraulic cylinder 15 retracts; the displacement sensor 14 on the asymmetric hydraulic cylinder 15 detects the retraction displacement of the piston rod in real time and sends it to the controller 17; The controller 17 compares the displacement command with the detected actual displacement, and the difference is corrected by an algorithm to output the corrected displacement command to the driver 18, so as to realize the position closed-loop control of the asymmetric hydraulic cylinder 15 and accurately reach the expected retracted position.

Embodiment 3, the output control process of the asymmetrical hydraulic cylinder 15:

The controller 17 accepts the external pressure command and simultaneously calculates the real-time pressure values of the piston rod two chambers detected by the second pressure sensor 11 and the third pressure sensor 13 of the two chambers of the asymmetric hydraulic cylinder 15. If the calculated piston rod output of the asymmetric hydraulic cylinder 15 When the pressure value is lower than the command pressure, the controller 17 issues an extension command to the driver 18, the driver 18 drives the servo motor 1 to rotate forward, the servo motor 1 drives the two-way quantitative pump 2 to output oil at the A port, and absorb oil at the B port. The conventional accumulator 6 provides two-way The oil suction flow at the 2B port of the quantitative pump, the electromagnetic ball valve 7 is electrically connected, and the pressure oil at the 2A port of the two-way quantitative pump enters the rodless chamber of the asymmetric hydraulic cylinder 15, resulting in an increase in the pressure of the rodless chamber, and the controller 17 compares the pressure command with the detected pressure The converted actual output pressure values are compared, and the difference is corrected by an algorithm to output a command to the driver 18, so as to realize the closed-loop control of the output of the asymmetric hydraulic cylinder 15 and precisely control the output. Similarly, if the calculated output pressure value of the piston rod of the asymmetric hydraulic cylinder 15 is greater than the command pressure, the controller 17 sends a retraction command to the driver 18, and the driver 18 drives the servo motor 1 to rotate in reverse, and the servo motor 1 drives the bidirectional quantitative pump 2B oil outlet, A port oil, the conventional accumulator 6 absorbs the oil flow of the two-way quantitative pump 2B port, the electromagnetic ball valve 7 is electrically connected, and the two-way quantitative pump 2A port absorbs the oil in the rodless chamber of the asymmetric hydraulic cylinder 15, thereby The pressure in the rodless chamber of the asymmetric hydraulic cylinder 15 is reduced; the controller 17 compares the pressure command with the actual output after the detected pressure is converted, and the difference is corrected by an algorithm to output the command to the driver 18, thereby realizing the asymmetric hydraulic cylinder. 15 output closed-loop control, precise control of output.

In summary, the utility model adopts a special structure constant pressure accumulator to control the rod chamber of the asymmetric hydraulic cylinder, so that the pressure of the back pressure chamber remains basically constant during the movement of the hydraulic cylinder; the rodless chamber of the asymmetric hydraulic cylinder is composed of The two-way pump driven by the servo motor is controlled. One side of the two-way pump is connected to the rodless chamber of the asymmetric hydraulic cylinder, and the other side of the two-way pump is connected to the low-pressure accumulator, so that the asymmetry is realized through the control of the servo motor. The pressure and flow control of the rodless cavity of the hydraulic cylinder; the displacement sensor is installed on the asymmetric hydraulic cylinder, and the pressure sensor is installed on the two chambers of the asymmetric hydraulic cylinder. The signals of the displacement sensor and the pressure sensor are connected to the controller, and the control command is output through the controller. For the servo motor driver, the servo motor driver drives the servo motor to run according to the instructions, so as to control the flow output of the bidirectional pump connected to the servo motor, and finally realize the rapid and precise control of the position and pressure of the hydraulic cylinder. Therefore, the utility model effectively overcomes various shortcomings in the prior art and has high industrial application value.

The above-mentioned embodiments only illustrate the principles and effects of the present utility model, but are not intended to limit the present utility model. Anyone familiar with this technology can modify or change the above-mentioned embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or changes made by those with ordinary knowledge in the technical field without departing from the spirit and technical ideas disclosed in the utility model should still be covered by the claims of the utility model.

Claims (10)

1. a constant backpressure Direct Drive Electro-hydraulic Servo System, it is characterized in that, including: controller, driver, servomotor, two-way quantitative pump and asymmetrical cylinder, described controller, driver are sequentially connected with servomotor, this controller is operated by servomotor described in described driver control, described servomotor, two-way quantitative pump are sequentially connected with asymmetrical cylinder, and described servomotor is by controlling two-way quantitative POF and direction, it is achieved the motor control of asymmetrical cylinder.

Constant backpressure Direct Drive Electro-hydraulic Servo System the most according to claim 1, it is characterized in that, also include constant voltage accumulator and conventional accumulator, described constant voltage accumulator connects with the rod chamber of described asymmetrical cylinder, and described conventional accumulator is respectively communicated with the first hydraulic fluid port of described two-way quantitative pump, the second hydraulic fluid port.

Constant backpressure Direct Drive Electro-hydraulic Servo System the most according to claim 2, it is characterised in that the 3rd hydraulic fluid port of described two-way quantitative pump connects the rodless cavity of described asymmetrical cylinder.

Constant backpressure Direct Drive Electro-hydraulic Servo System the most according to claim 1, it is characterised in that be provided with electromagnetic shut-off valve between rodless cavity and the rod chamber of described asymmetrical cylinder of described asymmetrical cylinder.

Constant backpressure Direct Drive Electro-hydraulic Servo System the most according to claim 4, it is characterised in that also include that the first relief valve and the second relief valve, described first relief valve reversely connect with described second relief valve, and it is connected to described electromagnetic shut-off valve two ends.

Constant backpressure Direct Drive Electro-hydraulic Servo System the most according to claim 5, it is characterized in that, also include that Solenoid ball valve, the oil-in of described Solenoid ball valve, oil-out are connected respectively the 3rd hydraulic fluid port of described two-way quantitative pump and the rodless cavity of described asymmetrical cylinder.

Constant backpressure Direct Drive Electro-hydraulic Servo System the most according to claim 6, it is characterized in that, also include the first check valve and the second check valve, the oil-in of described first check valve, oil-out are connected respectively second and third hydraulic fluid port of described two-way quantitative pump, and its oil-out is connected in the same direction with described Solenoid ball valve；The oil-in of described second check valve is connected between described first relief valve and the second relief valve, and its oil-out is connected between first and second hydraulic fluid port of described two-way quantitative pump.

Constant backpressure Direct Drive Electro-hydraulic Servo System the most according to claim 2, it is characterised in that described constant voltage accumulator and described conventional accumulator are correspondingly arranged the pressure transducer gathering oil circuit respectively.

Constant backpressure Direct Drive Electro-hydraulic Servo System the most according to claim 1, it is characterised in that the displacement transducer being provided with its piston rod telescopic displacement of collection of described asymmetrical cylinder.

Constant backpressure Direct Drive Electro-hydraulic Servo System the most according to claim 1, it is characterised in that the outfan of the piston rod of described asymmetrical cylinder connects load.