CN217107624U

CN217107624U - Hydraulic system of car dumper

Info

Publication number: CN217107624U
Application number: CN202220229639.7U
Authority: CN
Inventors: 李洋; 邹冬生; 李志峰; 陈强; 刘成; 邓劭华; 刘玉珑
Original assignee: Dalian Huarui Heavy Industry Group Co Ltd
Current assignee: Dalian Huarui Heavy Industry Group Co Ltd
Priority date: 2022-01-27
Filing date: 2022-01-27
Publication date: 2022-08-02
Anticipated expiration: 2032-01-27

Abstract

The utility model provides a tipper hydraulic system includes: power source pump station, pressure car device and by car device, the power source pump station includes: the oil tank is provided with an electromagnetic stop valve and a prepressing type air filter, an oil return filter connected with the oil tank and a butterfly valve connected with the oil tank; the electromagnetic stop valve is also provided with an air conditioner. The utility model discloses a servo motor's rotational speed is adjusted to the servo driver that exchanges, and the driver is according to the pressure and the rotational speed feedback signal of system, and the pressure and the rotational speed of pump package, required pressure and the flow of output system are adjusted in control. Meanwhile, the main elements and accessories such as a cooler, a pressure reducing valve and the like are eliminated, the structure of a hydraulic system is simplified, and convenience is provided for remote fault analysis of remote operation and maintenance in the future. The utility model discloses a 8 solenoid operated stop valves replace 8 liquid accuse check valve principles of 1 solenoid operated directional valve control, can independently move improvement system reliability.

Description

Hydraulic system of car dumper

Technical Field

The utility model relates to a bulk cargo loading and unloading mechanical equipment technical field particularly, especially relates to a tipper hydraulic system.

Background

The tippler is used for tipping bulk goods such as coal and ore in an open railway carriage, and is mainly applied to units such as a thermal power plant, a steel mill, a port and a wharf and the like. Except for part of all mechanical tipplers, most of the main actions of the tipplers are controlled by an advanced hydraulic system, and the tippler has the advantages of automatic operation of the whole tippler, low pressure, small damage to a railway wagon and the like. The hydraulic system of the tippler is an important core component of the tippler, and mainly controls a middle-pressure mechanism and a backup plate mechanism of the tippler so as to fix a wagon and complete overturning and unloading work.

At present, most enterprises in domestic market use the most and most common type of FZ1-2A type C rotor type single car tippler, which is a tippler of a fan-shaped pressing mechanism, the power source of the matched hydraulic system of the tippler adopts the principle that a three-phase asynchronous motor is matched with a vane pump or a plunger pump, because the tippler is a typical periodic heavy-duty process equipment, in a working period, a hydraulic station of the tippler is in an unloading state in 80% of the period and is in an effective working state in 20% of the period, the system has long-time large-discharge low-pressure unloading in the working period, the electric energy consumption is high, the phenomenon of heating and over-temperature is particularly common, because the hydraulic station of the tippler is arranged on a main body and rotates along with 175 degrees of equipment, the space is limited, the combination of a common three-phase asynchronous motor and a pump occupies a large area, the design of an oil tank is not suitable for large, and simultaneously, because a large amount of dust is contained in the process of on-site bulk material unloading, after mixing with dust collecting equipment steam, even add air cooling equipment, also let cooling equipment jam failure in short time, easily cause equipment to shut down, the system is revealed and is also strengthened, influences host computer operating efficiency, and the plant maintenance volume is huge, and the electric energy loss is big. In addition, the hydraulic vehicle-pressing control principle of the existing matched type is centrally controlled by 1 main valve with a large drift diameter, 8 vehicle-pressing beams cannot be independently controlled and locked, a hydraulic control one-way valve beside 8 vehicle-pressing oil cylinders and responsible for pressure maintaining of a fixed vehicle skin is opened and is independently controlled by 1 electromagnetic valve matched with a small pump and a medium pump in a dual pump in a power source, a branch of the hydraulic control one-way valve also comprises 1 precision control throttle valve, the requirement on the adjustment level is high, the whole linkage program is complex, the hydraulic control one-way valve is slightly debugged or improperly maintained, 1 oil cylinder has a problem or the electromagnetic valve has a fault, the vehicle skin derailment accident is directly caused, the economic loss is serious, and the derailment accident frequently occurred in recent years is mostly configured by the principle.

SUMMERY OF THE UTILITY MODEL

According to the technical problems that the system is large in heating, high in power consumption, large in maintenance difficulty and improper in maintenance mode, and serious economic loss can occur, the hydraulic system of the car dumper and the control method thereof are provided. The utility model discloses mainly join in marriage gear pump group control principle through AC servo motor belongs to the electric liquid servo system category, adjusts servo motor's rotational speed through AC servo driver, and the driver is according to the pressure and the rotational speed feedback signal of system, and the pressure and the rotational speed of pump group, required pressure and the flow of output system are adjusted in control. When the flow required by the system changes, the rotating speed of the servo motor changes along with the change of the flow command, so that the displacement of the pump changes, namely when the tipper is in an unloading state, the motor keeps a standby state, the displacement of the pump 0 is output, and when the tipper is pressed and depends on the tipper to act, the control of 'how much to give' is realized, the overflow loss of high pressure and low pressure is reduced, the heating of the system is reduced, and the effect of saving electric energy is also achieved. In addition, in the principle of controlling the car pressing, 8 electromagnetic stop valves are adopted to replace 1 electromagnetic directional valve to control the principle of 8 hydraulic control one-way valves, not only can 8 car pressing oil cylinders independently act, but also eight car pressing beams can be independently locked, the carriage derailing fault can be effectively solved, and the running reliability of the car dumper is greatly improved.

The utility model discloses contain a tipper hydraulic system, include: power source pump station, pressure car device and by car device, the power source pump station includes: the oil tank is provided with an electromagnetic stop valve and a prepressing type air filter, an oil return filter connected with the oil tank and a butterfly valve connected with the oil tank; the electromagnetic stop valve is also provided with an air conditioner;

the power source pump station is also provided with a control subunit; the control subunit includes: the system comprises a synchronous alternating current servo motor, a plurality of connecting valves, a pressure sensor connected with the connecting valves and a servo driver; the power source pump station adjusts the rotating speed of the synchronous alternating current servo motor through the servo driver, and the alternating current servo driver controls and adjusts a plurality of connecting valves according to feedback signals of the pressure and the rotating speed of the system acquired by the pressure sensor so as to adjust the pressure and the rotating speed of the power source pump station and output the pressure and the flow required by the system;

when the system flow changes, the rotating speed of the servo motor changes along with the flow, so that the displacement of the power source pump station changes, namely, when the tippler is in an unloading state, the motor keeps a standby state, and the displacement output of the power source pump station is zero.

Compared with the prior art, the utility model has the advantages of it is following:

1. the utility model discloses the system adopts novel energy-saving control technique, constitutes synchronous interchange servo motor and joins in marriage gear pump group control principle, adjusts servo motor's rotational speed through interchange servo driver, and the driver is according to the pressure and the rotational speed feedback signal of system, and the pressure and the rotational speed of pump package, required pressure and the flow of output system are adjusted in control. When the flow required by the system changes, the rotating speed of the servo motor changes along with the change of the flow command, so that the displacement of the pump changes, namely, when the tippler is in an unloading state, the motor keeps a standby state, the displacement of the pump 0 is output, and when the tippler is pressed and depends on the car, the control of 'how much the tippler needs to give', the overflow loss of high pressure and low pressure is reduced, the heating problem of a hydraulic system is thoroughly solved, the leakage problem of the hydraulic system caused by high temperature is avoided, the pollution to the operating environment is reduced, the service life of each seal of the hydraulic system is prolonged, a large amount of electric energy is saved, the comprehensive effect of energy conservation and emission reduction is achieved, and the tippler is connected with the national green environmental protection policy.

2. The utility model discloses the system adopts novel energy-saving control technique, and hydraulic system has cancelled principal elements such as cooler, relief pressure valve, annex in principle, and hydraulic system constitutes and can simplify. Because synchronous AC servo motor self has low rotational speed big moment of torsion, standby, weak magnetism speed extension, multistage rotational speed, high overload capacity, consequently hydraulic system's installed capacity can reduce, and the pump specification can reduce, and then whole hydraulic system volume reduces, and production manufacturing efficiency promotes, owing to reduced air-cooler component, on-the-spot maintenance volume is effectively alleviateed.

3. The utility model discloses the system adopts novel energy-saving control technique, establishes certain technical reserve for car dumper system unmanned operation scheme afterwards, provides convenience for long-range fortune dimension remote fault analysis afterwards.

4. The utility model discloses the system adopts 8 electromagnetic stop valves to replace 8 liquid accuse check valve principles of 1 solenoid directional valve control on the control principle of pressing the car, and not only 8 pressing the car hydro-cylinders can independent action, and consequently eight pressing the car roof beams can independent locking, and the carriage falls the trouble of saying and can effectively be solved, and tipper operational reliability promotes greatly.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required to be used in the description of the embodiments or the prior art are briefly introduced below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without inventive labor.

Fig. 1 is the schematic diagram of the hydraulic system of the car dumper.

In the figure: 1. the system comprises an oil tank, 2, an air conditioner, 3, electromagnetic stop valves I and 4, a pre-pressing air filter, 5, an oil return filter, 6, a butterfly valve, 7, a synchronous alternating current servo motor, 8, a gear pump, 9, a one-way valve, 10, a pressure sensor, 11, an electromagnetic overflow valve, 12, an electro-hydraulic reversing valve, 13, a hydraulic control one-way valve, 14, a sequence valve, 15, a compensation oil cylinder, 16, a limit switch, 17, a pressure sensor, 18, a throttle valve, 19, a one-way valve, 20, a speed regulating valve, 21, electromagnetic stop valves II and 22, a vehicle pressing oil cylinder, 23, a vehicle leaning oil cylinder, 24 and a servo driver.

Detailed Description

In order to make the technical solution of the present invention better understood, the technical solution of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by a person skilled in the art without creative efforts shall fall within the protection scope of the present invention.

It should be noted that the terms "first," "second," and the like in the description and claims of the present invention and in the drawings described above are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used is interchangeable under appropriate circumstances such that the embodiments of the invention described herein are capable of operation in sequences other than those illustrated or otherwise described herein. Furthermore, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed, but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.

As shown in fig. 1, the utility model provides a tippler hydraulic system, include: power source pump station, pressure car device and by car device, the power source pump station includes: the oil tank 1 is provided with an electromagnetic stop valve 3 and a prepressing type air filter 4, an oil return filter 5 connected with the oil tank 1, and a butterfly valve 6 connected with the oil tank 1; the electromagnetic cut-off valve 3 is also provided with an air conditioner 2.

The power source pump station is also provided with a control subunit; the control subunit includes: the synchronous alternating current servo motor 7, a plurality of connecting valves, a pressure sensor 10 connected with the connecting valves and a servo driver 24; the power source pump station adjusts the rotating speed of the synchronous alternating current servo motor 7 through the servo driver 24, and the alternating current servo driver 24 controls and adjusts a plurality of connecting valves according to feedback signals of the pressure and the rotating speed of the system acquired by the pressure sensor 10 so as to adjust the pressure and the rotating speed of the power source pump station and output the pressure and the flow required by the system; when the system flow changes, the rotating speed of the servo motor 7 changes along with the flow, so that the displacement of the power source pump station changes, namely, when the tippler is in an unloading state, the motor keeps a standby state, and the displacement output of the power source pump station is zero.

In the present application, a gear pump 8 is also provided in the control subunit;

the synchronous alternating current servo motor 7, the gear pump 8 and the gear pump 8 form a closed loop branch; the synchronous alternating current servo motor 7 is provided with a rotary encoder;

after an instruction signal is input through the upper computer PLC, the servo driver 24 controls and adjusts the pressure and the rotating speed of the gear pump 8 and outputs the actually required pressure and flow of the system according to the pressure sensor pressure 10 and the feedback signal of the rotary encoder of the synchronous alternating current servo motor 7. In the servo motor control process, according to the PID regulation, the servo driver 24 executes a speed closed-loop control mode before the set pressure is not reached, and the synchronous AC servo motor 7 runs at the set maximum rotating speed. When the set pressure is reached, the servo driver 24 executes a pressure closed-loop control mode, and the servo system is only responsible for maintaining the pressure constant and speed self-adaptation. In addition, the synchronous alternating current servo motor 7 has the characteristics of low rotating speed, standby, weak magnetic flux speed expansion, multi-stage rotating speed, high overload capacity, quick response and the like, so that the servo motor stops rotating in a standby mode under the unloading state of the hydraulic system of the tippler, and the working condition of low-pressure overflow of a large-displacement pump is avoided. Because the synchronous AC servo motor 7 has 1.3 times of high overload capacity in a short time, and the single execution action of the tippler is less than 8s, the synchronous AC servo motor 7 can be used in a periodic overload mode, so the power is lower than that of a conventional three-phase asynchronous motor, the installed capacity of a hydraulic system is reduced to a certain extent, the pump device formed by the synchronous AC servo motor and the gear pump 8 occupies a small area, a certain design space is reserved for the design of an oil tank, and the heat dissipation area of the oil tank is increased. Meanwhile, because the flow required by the car pressing action and the car leaning action is different, when the flow required by the system is changed, the rotating speed of the servo motor is changed along with the change of the flow command, and the flow is self-adaptive, so that the high-pressure overflow loss caused by the difference of the flow of different actions can be eliminated, and the throttle valves 18.1-4 and the speed regulating valves 20.1-8 only have the synchronous action for regulating in the car pressing and car leaning principle, and do not need to limit the flow required by the system.

In the present embodiment, the truck pressing device is integrated into a valve block by a plurality of electromagnetic cut-off valves and then coupled to the truck pressing cylinder 22; the vehicle pressing device comprises 8 electromagnetic stop valves, and the electromagnetic stop valves are respectively connected with rod cavities B of corresponding vehicle pressing oil cylinders in the oil cylinders; a cavity A in the electromagnetic stop valve is connected with a cavity B of the main control valve group 2; when the electromagnetic stop valves 7 are not powered, the vehicle pressing oil cylinder is locked by the rod cavity and cannot act, and only when the 8 electromagnetic stop valves are powered simultaneously, the main hydraulic reversing valve is matched to be powered to act so as to press the vehicle oil cylinder to act. At the moment, each oil cylinder can be independently locked, the starting principle of 8 hydraulic control one-way valves controlled by 1 electromagnetic directional valve is not the same as that of the prior art, when 1 electromagnetic directional valve of a control oil circuit fails or a control oil pipe is blocked, the starting of the hydraulic control one-way valves is not influenced, a pressing beam of the tipper cannot be loosened, and the wagon is not easy to derail.

According to the new principle characteristic, a pressure reducing valve does not need to be additionally arranged on the vehicle control branch, and because a servo motor closed-loop system is adopted, after an instruction signal is input through an upper computer PLC, the flow and the pressure adaptive to the upper computer PLC are provided according to the actual vehicle requirement, so that the pressure difference loss of the pressure reducing valve is reduced, and the system heating is reduced. An electro-hydraulic reversing valve 12.1 in the loop is used for controlling switching to be actively operated by a vehicle oil cylinder 23, hydraulic control one-way valves 13.1-2 are respectively used for pressure maintaining by a rod cavity and a rodless cavity of the vehicle oil cylinder, and speed regulating valves 20.1-8 are used for synchronous regulation by a vehicle plate and are not used for limiting total flow of branch circuits.

Specific application the utility model discloses a tipper hydraulic control method of system, including following step:

step S1, the system is electrified, and the power source pump station is started;

step S2: the power source pump station adjusts the rotating speed of the synchronous alternating current servo motor through a servo driver; the PLC programmable controller of the upper computer outputs digital pressure and flow control signals required by a hydraulic system, a professional electric control conversion module is adopted, the digital signals are converted into digital signals through a D/A conversion function and then input into a servo driver 24, the digital signals are converted into digital signals through the D/A conversion function and then input into a pressure sensor 10, the servo driver 24 controls the rotating speed of a servo motor 7, and therefore the control of the rotating speed of the gear pump is achieved, and finally the control of flow is achieved. The pressure sensor 10 will detect the pump outlet pressure signal instantaneously while achieving the highest limit of the system output pressure. And giving control signals of the electromagnetic electro-hydraulic directional valve 12.1 or 12.2 to control the directional valve to change direction, so as to realize the extending and retracting actions of the pressing and leaning vehicle. The pressure sensor converts the instantly detected pump outlet pressure signal into a digital signal through an A/D conversion function and a rotating speed signal of the servo motor 7 detected by a rotary encoder of the servo motor 7, and simultaneously feeds the digital signal back to the PLC, and outputs a control signal after PID logical operation, thereby finally realizing the closed-loop control of the speed and the pressure of the pressing and leaning motion. In the working process, the extending and retracting processes of the vehicle pressing oil cylinder 22 and the vehicle leaning oil cylinder 23 are speed control, and the pressure control is carried out in the pressure maintaining process.

Step S3: the alternating current servo driver controls and adjusts a plurality of connecting valves according to feedback signals of the pressure and the rotating speed of the system, which are acquired by the pressure sensor, so that the pressure and the rotating speed of the power source pump station are adjusted, and the pressure and the flow required by the system are output;

The first embodiment is as follows:

as an embodiment of the present application, with reference to fig. one, specifically in the control: the upper computer PLC inputs pressure P1 and flow Q1 commands to the servo driver 24, the electromagnets YH1 and YH3 are electrified, the hydraulic cylinder of the dumper stretches out, the servo driver 24 executes a speed closed-loop control mode before the set pressure is not reached according to PID regulation, the synchronous alternating current servo motor 7 runs at the set maximum rotating speed, when the hydraulic cylinder of the dumper stretches out to the set position, the limit switch sends a signal which is used as a dumper overturning interlocking signal, YH1 and YH3 are electrified, and the hydraulic cylinder of the dumper stops acting. Electromagnets YH1, YH6, YH7-1, YH7-2, YH7-3, YH7-4, YH7-5, YH7-6, YH7-7 and YH7-8 are energized, the servo driver 24 executes a speed closed-loop control mode before reaching the set pressure according to PID adjustment, the synchronous AC servo motor 7 runs at the set maximum speed, the vehicle-pressing cylinders 22.1 to 8 start clamping, when the system pressure reaches the set pressure of the pressure sensor 17, the pressure sensor 17 sends out a signal which serves as a rollover interlock signal and also as a pressure detection signal, and when the set pressure is reached, the servo driver 24 executes the pressure closed-loop control mode, the servo system is only responsible for maintaining the pressure constant and the speed is self-adaptive, and when YH7-1, YH7-2, YH7-3, YH7-4, YH7-5 and YH7-6, YH7-7 and YH7-8, the detection was terminated when power was lost. When the tippler turns over to a certain angle, the electromagnets YH1, YH2 and YH6 lose power. In the overturning process of the tippler, after the compensation cylinder 15 finishes compensation, the tippler retracts to the rear limit, the limit switch 16.1 sends out signals, and the electromagnets YH7-1, YH7-2, YH7-3, YH7-4, YH7-5, YH7-6, YH7-7 and YH7-8 lose power. If the tippler is turned to 110 degrees, the compensation cylinder 16.1 is not retracted to the rear limit switch, the main command controller sends out a signal to forcibly power off the electromagnets YH7-1, YH7-2, YH7-3, YH7-4, YH7-5, YH7-6, YH7-7 and YH 7-8. During the overturning process of the tippler, if the system pressure is reduced and is lower than the set value of the pressure sensor 17 for some reason, the pressure detection signal is interrupted. At this time, electromagnets YH7-1, YH7-2, YH7-3, YH7-4, YH7-5, YH7-6, YH7-7 and YH7-8 should be immediately de-energized. At the moment, the upper computer PLC inputs a standby instruction to the servo driver 24, namely, the tipper stops rotating in the process of returning to 0 degrees from 110 degrees to 175 degrees, the synchronous alternating current servo motor 7 is in standby, so that the gear pump 8 outputs zero flow, zero overflow loss in the unloading process is achieved, after the tipper returns to 0 degree, the electromagnets YH1, YH5, YH7-1, YH7-2, YH7-3, YH7-4, YH7-5, YH7-6, YH7-7 and YH7-8 are electrified, the vehicle pressing cylinder is released, and after the tipper returns to the original position, the limit switches send signals, and the YH1, YH5, YH7-1, YH7-2, YH7-3, YH7-4, YH7-5, YH7-6, YH7-7 and YH7-8 are electrified. Electromagnets YH1, YH4 are energized and retracted to their original positions by the vehicle cylinders. From this moment to the next working sequence, the upper computer PLC inputs a standby instruction to the servo driver 24, and the synchronous AC servo motor 7 is in standby in the whole waiting process without any low-voltage large-displacement overflow loss.

The above embodiment numbers of the present invention are only for description, and do not represent the advantages and disadvantages of the embodiments.

In the above embodiments of the present invention, the descriptions of the respective embodiments have respective emphasis, and for parts that are not described in detail in a certain embodiment, reference may be made to the related descriptions of other embodiments.

In the embodiments provided in the present application, it should be understood that the disclosed technology can be implemented in other ways. The above-described embodiments of the apparatus are merely illustrative, and for example, the division of the units may be a logical division, and in actual implementation, there may be another division, for example, multiple units or components may be combined or integrated into another system, or some features may be omitted, or not executed. In addition, the shown or discussed mutual coupling or direct coupling or communication connection may be an indirect coupling or communication connection through some interfaces, units or modules, and may be in an electrical or other form.

The units described as separate parts may or may not be physically separate, and parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of the embodiment.

In addition, functional units in the embodiments of the present invention may be integrated into one processing unit, or each unit may exist alone physically, or two or more units are integrated into one unit. The integrated unit can be realized in a form of hardware, and can also be realized in a form of a software functional unit.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; although the present invention has been described in detail with reference to the foregoing embodiments, it should be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; such modifications and substitutions do not depart from the spirit and scope of the present invention.

Claims

1. The utility model provides a tippler hydraulic system which characterized in that includes: power source pump station, pressure car device and by car device, the power source pump station includes: the device comprises an oil tank (1) provided with an electromagnetic stop valve I (3) and a pre-pressing type air filter (4), an oil return filter (5) connected with the oil tank (1), and a butterfly valve (6) connected with the oil tank (1); the electromagnetic stop valve I (3) is also provided with an air conditioner (2);

the power source pump station is also provided with a control subunit; the control subunit includes: a synchronous AC servo motor (7), a plurality of connecting valves, a pressure sensor (10) connected with the connecting valves and a servo driver (24); the power source pump station adjusts the rotating speed of the synchronous alternating current servo motor (7) through the servo driver (24), and the alternating current servo driver (24) controls and adjusts a plurality of connecting valves according to feedback signals of the pressure and the rotating speed of the system, which are acquired by the pressure sensor (10), so that the pressure and the rotating speed of the power source pump station are adjusted, and the pressure and the flow required by the system are output;

when the system flow changes, the rotating speed of the servo motor (7) changes along with the flow, so that the displacement of the power source pump station changes, namely, when the tipper is in an unloading state, the motor keeps a standby state, and the displacement output of the power source pump station is zero.

2. The hydraulic system of the tippler as claimed in claim 1, wherein said control subunit further comprises a gear pump (8);

the synchronous alternating current servo motor (7), the gear pump (8) and the gear pump (8) form a closed loop branch; the synchronous alternating current servo motor (7) is provided with a rotary encoder;

after an instruction signal is input through an upper computer PLC, the servo driver (24) controls and adjusts the pressure and the rotating speed of the gear pump (8) and outputs the actually required pressure and flow of the system according to feedback signals of the rotary encoder, which are carried by the pressure sensor (10) and the synchronous alternating current servo motor (7).

3. The hydraulic system of the car dumper according to claim 1,

the car pressing device is integrated into a valve bank through a plurality of electromagnetic stop valves and then combined on a car pressing oil cylinder (22); the vehicle pressing device comprises 8 electromagnetic stop valves, and the electromagnetic stop valves are respectively connected with rod cavities B of corresponding vehicle pressing oil cylinders in the oil cylinders; a cavity A in the electromagnetic stop valve is connected with a cavity B of the main control valve group 2; when the electromagnetic stop valves II (21) are not electrified, the vehicle pressing oil cylinder is locked by a rod cavity and cannot act, and only when the 8 electromagnetic stop valves are electrified simultaneously, the main hydraulic reversing valve is matched to be electrified to act so as to further drive the vehicle pressing oil cylinder to act.