CN112172647A

CN112172647A - Self-discharging vehicle

Info

Publication number: CN112172647A
Application number: CN202011126977.XA
Authority: CN
Inventors: 不公告发明人
Original assignee: Changzhou Aishangxue Education Technology Co ltd
Current assignee: HANGZHOU TONGYU INDUSTRY CO LTD
Priority date: 2018-11-08
Filing date: 2018-11-08
Publication date: 2021-01-05
Anticipated expiration: 2038-11-08
Also published as: CN112172646A; CN109466398B; CN112172647B; CN109466398A

Abstract

A dumper is provided, the lifting and carriage linkage device of which comprises a carriage body, a rear door, an oil tank, a hydraulic pump, a lifting oil cylinder, a manual reversing valve, a stop block, a first pressure switch, a second pressure switch, a tensioning motor, a worm gear, a magnetic ring, a sensor, a main controller, a motor driver and a mounting rack; the worm wheel is fixedly connected to the rear door, the body of the tensioning motor is fixedly connected to the mounting frame, and the output shaft of the tensioning motor is in transmission connection with the worm; the worm is in transmission connection with the worm wheel; the magnetic ring is fixedly connected to an output shaft of the tensioning motor; the sensor is fixedly connected to the body of the tensioning motor; the first pressure switch, the second pressure switch, the motor driver and the sensor are all electrically connected with the main controller; the tensioning motor is electrically connected with the motor driver. The invention can realize that the back door is automatically opened when the piston rod of the lifting oil cylinder extends out, and the back door is automatically closed when the piston rod of the lifting oil cylinder retracts.

Description

Self-discharging vehicle

Technical Field

The invention relates to a dumper, in particular to a dumper.

Background

As shown in fig. 9 and 10, the dump truck is a vehicle that lifts the carriage body 50 by the lift cylinder 63 to tilt a certain angle and automatically unloads goods, and the dump truck can greatly save unloading time and labor force and improve production efficiency. The carriage of the dump truck in the prior art comprises a carriage body 50 and a rear door 51, wherein the carriage body 50 is hinged with a frame 80 of the dump truck, the upper end of the rear door 51 is hinged with the upper end of the carriage body 50, and the lower end of the rear door 51 is connected with the lower end of the carriage body 50 through a locking mechanism. As shown in fig. 11, the lifting apparatus of the prior art includes an oil tank 61, a hydraulic pump 62, a lifting cylinder 63 and a manual directional valve 64, an oil inlet of the hydraulic pump 62 is communicated with the oil tank 61, an oil outlet of the hydraulic pump 62 is communicated with an oil inlet P of the manual directional valve 64, an execution port a of the manual directional valve 64 is communicated with a rodless cavity of the lifting cylinder 63, and an execution port B of the manual directional valve 64 is communicated with a rod cavity of the lifting cylinder 63, as shown in fig. 10, a cylinder 63-1 of the lifting cylinder 63 is hinged to a frame 80, a piston rod 63-2 of the lifting cylinder 63 is hinged to a carriage 50, when the piston rod 63-2 of the lifting cylinder 63 extends, the carriage 50 can be lifted and unloaded, and when the piston rod 63-2 of the lifting cylinder 63 retracts, the carriage 50 can be unloaded. The carriage of the dump truck in the prior art cannot be linked with the lifting device, so that the rear door 51 cannot be automatically opened when the piston rod 63-2 of the lifting oil cylinder 63 extends, and the rear door 51 cannot be automatically closed when the piston rod 63-2 of the lifting oil cylinder 63 retracts. The opening and closing of the rear door 51 requires the locking device to be manually opened and closed, which is inconvenient, and causes great working strength and low working efficiency for drivers. The requirement of self-unloading in a narrow space cannot be met.

Disclosure of Invention

The invention aims to provide a lifting and carriage linkage device of a dump truck, wherein a rear door can be automatically opened when a piston rod of a lifting oil cylinder extends out, and the rear door can be automatically closed when the piston rod of the lifting oil cylinder retracts.

In order to achieve the purpose, the invention adopts the following technical scheme: a lifting and carriage linkage device of a dump truck comprises a carriage body, a rear door, an oil tank, a hydraulic pump, a lifting oil cylinder and a manual reversing valve; the lifting oil cylinder comprises a cylinder body and a piston rod; a piston rod of the lifting oil cylinder is hinged with the carriage body; the upper end part of the rear door is hinged with the upper end part of the carriage body, and the rear door is provided with an opening position and a closing position; an oil inlet of the hydraulic pump is communicated with the oil tank, and an oil outlet of the hydraulic pump is communicated with an oil inlet P of the manual reversing valve;

the device also comprises a stop block, a first pressure switch, a second pressure switch, a tensioning motor, a worm wheel, a magnetic ring, a sensor, a main controller, a motor driver and a mounting rack; the worm wheel is fixedly connected to the rear door, and the circle center of the worm wheel is coaxial with the hinge point 01 of the carriage body and the rear door; the machine body of the tensioning motor is fixedly connected to the mounting frame, and an output shaft of the tensioning motor is in transmission connection with one end of the worm; the worm is rotatably connected to the mounting frame, and the other end of the worm is in transmission connection with the worm wheel to form a worm and gear mechanism; the magnetic ring is fixedly connected to an output shaft of the tensioning motor; the sensor is fixedly connected to the body of the tensioning motor and corresponds to the magnetic ring; the stop block is fixedly connected to the carriage body, and the rear door is limited by the stop block when rotating anticlockwise to an opening position; an execution port A of the manual reversing valve is respectively communicated with a rodless cavity of the lifting oil cylinder and a control port K of the first pressure switch, and an execution port B of the manual reversing valve is respectively communicated with a rod cavity of the lifting oil cylinder and a control port K of the second pressure switch; the first pressure switch, the second pressure switch, the motor driver and the sensor are electrically connected or wirelessly communicated with the main controller; the tensioning motor is electrically connected or wirelessly communicated with the motor driver; when the pressure value of the control port K of the first pressure switch is larger than a first pressure value set in the main controller, the main controller controls the output shaft of the tensioning motor to rotate forwards through the motor driver; when the rotating speed value of the sensor is equal to the set rotating speed value in the main controller, the main controller controls the output shaft of the tensioning motor to stop rotating forwards through the motor driver; when the pressure value of the control port K of the second pressure switch is larger than a second pressure value set in the main controller, the main controller controls the output shaft of the tensioning motor to rotate reversely through the motor driver; when the rotating speed value of the sensor is equal to the set rotating speed value in the main controller, the main controller controls the output shaft of the tensioning motor to stop rotating reversely through the motor driver.

The sensor support is also included; the sensor is fixedly connected to the body of the tensioning motor through a sensor support.

The device also comprises a coupler; and an output shaft of the tensioning motor is in transmission connection with one end of the worm 10 through a coupler.

Also includes a safety valve; the safety valve is arranged on an oil channel from an oil outlet of the hydraulic pump to the oil tank.

The device also comprises a filter; the filter is arranged on an oil channel from the oil tank to an oil inlet of the hydraulic pump.

The invention has the following positive effects: (1) the worm wheel is fixedly connected to the rear door, and the circle center of the worm wheel is coaxial with the hinge point 01 of the carriage body and the rear door; the machine body of the tensioning motor is fixedly connected to the mounting frame, and an output shaft of the tensioning motor is in transmission connection with one end of the worm; the worm is rotationally connected to the mounting frame, and the other end of the worm is in transmission connection with the worm wheel to form a worm and gear mechanism; the magnetic ring is fixedly connected to an output shaft of the tensioning motor; the sensor is fixedly connected to the body of the tensioning motor and corresponds to the magnetic ring; the stop block is fixedly connected to the carriage body, and the rear door is limited by the stop block when rotating anticlockwise to an opening position; an execution port A of the manual reversing valve is respectively communicated with a rodless cavity of the lifting oil cylinder and a control port K of the first pressure switch, and an execution port B of the manual reversing valve is respectively communicated with a rod cavity of the lifting oil cylinder and a control port K of the second pressure switch; the first pressure switch, the second pressure switch, the motor driver and the sensor are electrically connected or wirelessly communicated with the main controller; the tensioning motor is electrically connected with the motor driver or in wireless communication connection; when the pressure value of the control port K of the first pressure switch is larger than a first pressure value set in the main controller, the main controller controls the output shaft of the tensioning motor to rotate forwards through the motor driver; when the rotating speed value of the sensor is equal to the set rotating speed value in the main controller, the main controller controls the output shaft of the tensioning motor to stop rotating forwards through the motor driver; when the pressure value of the control port K of the second pressure switch is larger than a second pressure value set in the main controller, the main controller controls the output shaft of the tensioning motor to rotate reversely through the motor driver; when the rotating speed value of the sensor is equal to the set rotating speed value in the main controller, the main controller controls the output shaft of the tensioning motor to stop rotating reversely through the motor driver, so that when the manual reversing valve is operated to enable an oil inlet P of the manual reversing valve to be communicated with the execution port A, pressure oil in the hydraulic pump reaches a rodless cavity of the lifting oil cylinder through the manual reversing valve, a piston rod of the lifting oil cylinder extends out, meanwhile, the pressure oil in the hydraulic pump can also reach a control port K of the first pressure switch through the manual reversing valve, the pressure value of the control port K of the first pressure switch is larger than a first pressure value set in the main controller, the main controller controls the output shaft of the tensioning motor to rotate forwards through the motor driver to drive the worm gear to rotate anticlockwise, and the rear door can rotate anticlockwise around a hinge point 01 of the carriage body and the rear door together with the. So that the back door can be automatically opened. When the back door is opened to the opening position, the back door can not rotate anticlockwise any more, and the worm wheel can not rotate anticlockwise any more, so that the rotating speed of the output shaft of the tensioning motor and the worm is reduced to 0 rpm. The rotation speed value of the sensor is 0rpm, the rotation speed value of the sensor is equal to the set rotation speed value in the main controller, the main controller controls the output shaft of the tensioning motor to stop rotating forwards through the motor driver, and at the moment, the rear door rotates to the opening position from the closing position, namely, the rear door can be automatically opened when the piston rod of the lifting oil cylinder extends out. When the manual reversing valve is operated to enable an oil inlet P of the manual reversing valve to be communicated with an execution port B, pressure oil in the hydraulic pump reaches a rod cavity of the lifting oil cylinder through the manual reversing valve, a piston rod of the lifting oil cylinder retracts, meanwhile, the pressure oil in the hydraulic pump can also reach a control port K of the second pressure switch through the manual reversing valve, the pressure value of the control port K of the second pressure switch is larger than a second pressure value set in the main controller, the main controller controls an output shaft of the tensioning motor to rotate reversely through the motor driver to drive the worm gear to rotate clockwise, and the back door can rotate clockwise around a hinge point 01 of the carriage body and the back door along with the worm gear. Thus, the rear door can be automatically closed. When the rear door is closed to a closed position, the carriage body limits the position, at the moment, the rear door cannot rotate clockwise any more, and the worm wheel cannot rotate clockwise any more, so that the rotating speed of the output shaft of the tensioning motor and the worm is reduced to 0 rpm. The rotating speed value of the sensor is 0rpm, the rotating speed value of the sensor is equal to the set rotating speed value in the main controller, the main controller controls the output shaft of the tensioning motor to stop rotating reversely through the motor driver, and at the moment, the rear door rotates to the closing position from the opening position, namely, the rear door can be automatically closed when the piston rod of the lifting oil cylinder retracts. Therefore, the method is very convenient, and the working intensity of a driver is low, and the working efficiency is high. The self-unloading requirement in a narrow space can be met.

Drawings

FIG. 1 is a schematic diagram of the structure of the present invention;

FIG. 2 is a schematic top view of FIG. 1;

FIG. 3 is an enlarged schematic view of A of FIG. 1;

FIG. 4 is an enlarged schematic view of B of FIG. 2;

FIG. 5 is an enlarged schematic view of C of FIG. 2 (and also a top schematic view of FIG. 6);

FIG. 6 is a schematic front view of the rear door of FIG. 5 in a closed position;

FIG. 7 is a schematic front view of the rear door of FIG. 5 in an open position;

FIG. 8 is a control schematic of the present invention;

FIG. 9 is a schematic structural view of a carriage of a dump truck of the prior art;

FIG. 10 is a schematic illustration of the configuration of FIG. 9 with the car mounted on the dump truck;

fig. 11 is a schematic diagram of a lifting device of the prior art.

The reference numbers in the above figures are as follows: the device comprises a stop block 1, a horizontal section 1-1, a first pressure switch 2, a second pressure switch 3, a tensioning motor 4, a worm 5, a worm wheel 6, a magnetic ring 7, a sensor 8, a main controller 9, a motor driver 10, a sensor support 11, a coupler 12, a safety valve 13, a filter 14, an installation rack 15, a copper sleeve 16, a pin shaft 17, a worm copper sleeve 18, a compartment body 50, a rear door 51, an oil tank 61, a hydraulic pump 62, a lifting oil cylinder 63, a cylinder body 63-1, a piston rod 63-2, a manual reversing valve 64 and a rack 80.

Detailed Description

The invention is further described below with reference to the accompanying drawings and the examples given.

As shown in fig. 1 to 4, 8 and 10, a lifting and carriage linkage device of a dump truck comprises a carriage body 50, a rear door 51, an oil tank 61, a hydraulic pump 62, a lifting oil cylinder 63 and a manual reversing valve 64; the lifting oil cylinder 63 comprises a cylinder body 63-1 and a piston rod 63-2, and the piston rod 63-2 of the lifting oil cylinder 63 is hinged with the carriage body 50; as shown in fig. 3 and 4, the upper end of the rear door 51 is hinged to the upper end of the carriage 50 by a pin 17, so that the rear door 51 can rotate around the carriage 50, a copper sleeve 16 is arranged at the rotating position of the rear door 51, and the rear door 51 has an open position and a closed position; as shown in fig. 6, in the present embodiment, when the rear door 51 is in the vertical position, the rear door 51 is in the closed position; as shown in fig. 7, when the rear door 51 is in the horizontal position, the rear door 51 is in the open position. When the rear door 51 of the present invention is closed, the rear door 51 can close the carriage 50; after the rear door 51 is rotated 90 degrees counterclockwise from the closed position, the rear door 51 is in the open position. As shown in fig. 8, an oil inlet of the hydraulic pump 62 is communicated with the oil tank 61, and an oil outlet of the hydraulic pump 62 is communicated with an oil inlet P of the manual directional valve 64;

as shown in fig. 1 to 8, the device further comprises a stop block 1, a first pressure switch 2, a second pressure switch 3, a tensioning motor 4, a worm 5, a worm wheel 6, a magnetic ring 7, a sensor 8, a main controller 9, a motor driver 10 and a mounting rack 15; in this embodiment, the magnetic ring 7 is a two-pair magnetic ring manufactured by Jiangsu Xinxu magnetoelectric technology Limited. The sensor 8 is a Hall sensor with the model MT 4401. The tensioning motor 4 is a servomotor of the type TLSM 04-M00330. The main controller 9 is a PLC programmable controller, and selects a Mitsubishi FX2NC-PLC programmable controller, and the motor driver 10 selects a direct current motor driving board with the model number of LMD 18200T. The first pressure switch 2 and the second pressure switch 3 are of the type DNM-03P-100K-21B. As shown in fig. 2 to 4, the worm wheel 6 is fixedly connected to the rear door 51, and the center of the worm wheel 6 is coaxial with the hinge point 01 of the carriage 50 and the rear door 51; the worm wheel 6 is welded to the rear door 51 in this embodiment. The machine body of the tensioning motor 4 is fixedly connected to the mounting frame 15, and an output shaft of the tensioning motor 4 is in transmission connection with one end of the worm 5; when the output shaft of the tension motor 4 rotates, the worm 5 rotates synchronously with the output shaft of the tension motor 4. As shown in fig. 3, the worm 5 is rotatably connected to the mounting frame 15 through a worm copper sleeve 18, and the other end of the worm 5 is in transmission connection with the worm wheel 6 and forms a worm and gear mechanism; the magnetic ring 7 is fixedly connected to an output shaft of the tensioning motor 4; in this embodiment, the magnetic ring 7 is adhered to the output shaft of the tension motor 4, and when the output shaft of the tension motor 4 rotates, the magnetic ring 7 can rotate synchronously. The sensor 8 is fixedly connected to the body of the tensioning motor 4 and corresponds to the magnetic ring 7; as shown in fig. 5 to 7, the stopper 1 is fixedly connected to the carriage 50, and the rear door 51 is limited by the stopper 1 when rotating counterclockwise to the open position; at this time, the rear door 51 cannot continue to rotate counterclockwise. In this embodiment, the stopper 1 is 7-shaped and welded to the carriage 50, and the horizontal section 1-1 of the stopper 1 limits the rear door 51 to the open position. As shown in fig. 8, the actuating port a of the manual directional valve 64 is respectively communicated with the rodless cavity of the lift cylinder 63 and the control port K of the first pressure switch 2, and the actuating port B of the manual directional valve 64 is respectively communicated with the rod cavity of the lift cylinder 63 and the control port K of the second pressure switch 3; the first pressure switch 2, the second pressure switch 3, the motor driver 10 and the sensor 8 are all electrically connected or wirelessly communicated with the main controller 9; the tensioning motor 4 is electrically connected or wirelessly communicated with a motor driver 10; when the pressure value of the control port K of the first pressure switch 2 is greater than the first pressure value set in the main controller 9, the main controller 9 controls the output shaft of the tensioning motor 4 to rotate forwards through the motor driver 10; at this time, the worm wheel 6 rotates counterclockwise. When the rotating speed value of the sensor 8 is equal to the set rotating speed value in the main controller 9, the main controller 9 controls the output shaft of the tensioning motor 4 to stop rotating forwards through the motor driver 10; when the pressure value of the control port K of the second pressure switch 3 is greater than a second pressure value set in the main controller 9, the main controller 9 controls the output shaft of the tensioning motor 4 to rotate reversely through the motor driver 10; at this time, the worm wheel 6 rotates clockwise. When the rotation speed value of the sensor 8 is equal to the rotation speed value set in the main controller 9, the output shaft of the tension motor 4 is controlled by the main controller 9 through the motor driver 10 to stop reverse rotation. The first pressure value set in the main controller 9 is a pressure value of a control port K of the first pressure switch 2 when pressure oil is introduced into a rodless cavity of the lifting oil cylinder 63 when the piston rod 63-2 of the lifting oil cylinder 63 extends, which is obtained through testing, and in this embodiment, the first pressure value set in the main controller 9 is 6 Mpa; the second pressure value set in the main controller 9 is a pressure value of the control port K of the second pressure switch 3 when the pressure oil is introduced into the rod cavity of the lift cylinder 63 when the piston rod 63-2 of the lift cylinder 63 retracts, which is obtained through testing, and in this embodiment, the second pressure value set in the main controller 9 is 2 Mpa; the set rotation speed value in the main controller 9 is the rotation speed value of the output shaft of the tensioning motor 4 detected by the sensor 8 when the rear door 51 is turned from the closed position to the open position or the rear door 51 is turned from the open position to the closed position. In this embodiment, the set rotation speed value of the main controller 9 is 0rpm, that is, when the rotation speed value of the sensor 8 is equal to the set rotation speed value of 0rpm of the main controller 9, the rear door 51 is turned from the closed position to the open position or the rear door 51 is turned from the open position to the closed position.

As shown in fig. 3, further includes a sensor holder 11; the sensor 8 is fixedly connected to the body of the tensioning motor 4 through a sensor bracket 11. In this embodiment, the sensor 8 is fixedly connected to the sensor bracket 11 through a fastener, and the sensor bracket 11 is fixedly connected to the body of the tension motor 4 through a fastener.

The device also comprises a coupler 12; an output shaft of the tensioning motor 4 is in transmission connection with one end of the worm 10 through a coupler 12, and the coupler 12 is axially positioned by a set screw.

As shown in fig. 8, a safety valve 13 is further included; the relief valve 13 is provided on an oil passage from an oil outlet of the hydraulic pump 62 to the oil tank 61.

A filter 14 is also included; the filter 14 is provided on an oil passage from the oil tank 61 to an oil inlet of the hydraulic pump 62.

As shown in fig. 10, when the invention is used, the cylinder body 63-1 of the lift cylinder 63 is hinged on the frame 80 of the dump truck, the carriage body 50 is hinged with the frame 80 of the dump truck, and as shown in fig. 1 and 4, the mounting frame 15 is fixedly connected on the carriage body 50 through a fastener.

The working principle of the invention is as follows: when the carriage 50 of the dump truck needs to be lifted, the manual directional control valve 64 is operated, an oil inlet P of the manual directional control valve 64 is communicated with the execution port A, pressure oil in the hydraulic pump 62 reaches a rodless cavity of the lifting oil cylinder 63 through the manual directional control valve 64, a piston rod 63-2 of the lifting oil cylinder 63 extends out, meanwhile, the pressure oil in the hydraulic pump 62 can also reach a control port K of the first pressure switch 2 through the manual directional control valve 64, the pressure value of the control port K of the first pressure switch 2 is larger than a first pressure value set in the main controller 9, and the main controller 9 controls the output shaft of the tensioning motor 4 to rotate forwards through the motor driver 10. Because the output shaft of tensioning motor 4 is connected with the one end transmission of worm 5, the other end transmission of worm 5 is connected with worm wheel 6, therefore tensioning motor 4's output shaft corotation can drive worm wheel 6 anticlockwise rotation. And because the worm wheel 6 is fixedly connected to the back door 51, and the circle center of the worm wheel 6 is coaxial with the hinge point 01 of the carriage 50 and the back door 51, the back door 51 can rotate counterclockwise around the hinge point 01 of the carriage 50 and the back door 51 along with the worm wheel 6. So that the rear door 51 can be automatically opened. When the back door 51 is opened to the open position, the back door 51 cannot rotate counterclockwise any more and the worm wheel 6 cannot rotate counterclockwise any more because the back door 51 is limited by the stopper 1 when rotating counterclockwise to the open position, so that the rotation speed of the output shaft of the tensioning motor 4 and the worm 10 is reduced to 0 rpm. The rotation speed value of the sensor 8 is also 0rpm, the rotation speed value of the sensor 8 is equal to the set rotation speed value 0rpm in the main controller 9, the main controller 9 controls the output shaft of the tensioning motor 4 through the motor driver 10 to stop rotating forwards, and at this time, the rear door 51 rotates to the opening position from the closing position, namely, the rear door 51 can be automatically opened when the piston rod 63-2 of the lifting oil cylinder 63 extends out.

When the carriage 50 of the dump truck needs to be put down, the manual reversing valve 64 is operated, an oil inlet P of the manual reversing valve 64 is communicated with the execution port B, the pressure oil in the hydraulic pump 62 reaches the rod cavity of the lifting oil cylinder 63 through the manual reversing valve 64, the piston rod 63-2 of the lifting oil cylinder 63 retracts, meanwhile, the pressure oil in the hydraulic pump 62 can also reach the control port K of the second pressure switch 3 through the manual reversing valve 64, the pressure value of the control port K of the second pressure switch 3 is larger than the second pressure value set in the main controller 9, and the main controller 9 controls the output shaft of the tensioning motor 4 to reversely rotate through the motor driver 10. Because the output shaft of tensioning motor 4 is connected with the one end transmission of worm 5, the other end transmission of worm 5 is connected with worm wheel 6, therefore tensioning motor 4's output shaft reversal can drive worm wheel 6 clockwise rotation. And because the worm wheel 6 is fixedly connected to the back door 51, and the center of the worm wheel 6 is coaxial with the hinge point 01 of the carriage 50 and the back door 51, the back door 51 can rotate clockwise around the hinge point 01 of the carriage 50 and the back door 51 along with the worm wheel 6. So that the rear door 51 can be automatically closed. When the rear door 51 is closed to a closed position, the carriage 50 limits the position, at this time, the rear door 51 can not rotate clockwise any more, and the worm wheel 6 can not rotate clockwise any more, so that the rotating speed of the output shaft of the tensioning motor 4 and the worm 10 is reduced to 0 rpm. The rotation speed value of the sensor 8 is 0rpm, the rotation speed value of the sensor 8 is equal to the set rotation speed value 0rpm in the main controller 9, the main controller 9 controls the output shaft of the tensioning motor 4 through the motor driver 10 to stop rotating reversely, and the rear door 51 rotates from the open position to the closed position, namely the rear door 51 can be automatically closed when the piston rod 63-2 of the lifting oil cylinder 63 retracts. Therefore, the method is very convenient, and the working intensity of a driver is low, and the working efficiency is high. The self-unloading requirement in a narrow space can be met.

Claims

1. A dump truck comprises a lifting and carriage linkage device, wherein the lifting and carriage linkage device comprises a carriage body (50), a rear door (51), an oil tank (61), a hydraulic pump (62), a lifting oil cylinder (63) and a manual reversing valve (64); the lifting oil cylinder (63) comprises a cylinder body (63-1) and a piston rod (63-2); a piston rod (63-2) of the lifting oil cylinder (63) is hinged with the carriage body (50); the upper end part of the rear door (51) is hinged with the upper end part of the carriage body (50), and the rear door (51) is provided with an opening position and a closing position; an oil inlet of the hydraulic pump (62) is communicated with the oil tank (61), and an oil outlet of the hydraulic pump (62) is communicated with an oil inlet P of the manual reversing valve (64); the method is characterized in that:

the lifting and carriage linkage device of the dump truck further comprises a stop block (1), a first pressure switch (2), a second pressure switch (3), a tensioning motor (4), a worm (5), a worm wheel (6), a magnetic ring (7), a sensor (8), a main controller (9), a motor driver (10) and a mounting rack (15); the worm wheel (6) is fixedly connected to the rear door (51), and the circle center of the worm wheel (6) is coaxial with the hinge point 01 of the carriage body (50) and the rear door (51); the machine body of the tensioning motor (4) is fixedly connected to the mounting frame (15), and an output shaft of the tensioning motor (4) is in transmission connection with one end of the worm (5); the worm (5) is rotatably connected to the mounting frame (15), and the other end of the worm (5) is in transmission connection with the worm wheel (6) to form a worm and gear mechanism; the magnetic ring (7) is fixedly connected to an output shaft of the tensioning motor (4); the sensor (8) is fixedly connected to the body of the tensioning motor (4) and corresponds to the magnetic ring (7); the stop block (1) is fixedly connected to the carriage body (50), and the rear door (51) is limited by the stop block (1) when rotating anticlockwise to an opening position; an execution port A of the manual reversing valve (64) is respectively communicated with a rodless cavity of the lifting oil cylinder (63) and a control port K of the first pressure switch (2), and an execution port B of the manual reversing valve (64) is respectively communicated with a rod cavity of the lifting oil cylinder (63) and a control port K of the second pressure switch (3); the first pressure switch (2), the second pressure switch (3), the motor driver (10) and the sensor (8) are electrically connected or wirelessly communicated with the main controller (9); the tensioning motor (4) is electrically connected or wirelessly communicated with the motor driver (10);

when the pressure value of a control port K of the first pressure switch (2) is larger than a first pressure value set in the main controller (9), the main controller (9) controls the output shaft of the tensioning motor (4) to rotate forwards through the motor driver (10);

when the rotating speed value of the sensor (8) is equal to the set rotating speed value in the main controller (9), the main controller (9) controls the output shaft of the tensioning motor (4) to stop rotating forwards through the motor driver (10); when the pressure value of the control port K of the second pressure switch (3) is larger than a second pressure value set in the main controller (9), the main controller (9) controls the output shaft of the tensioning motor (4) to rotate reversely through the motor driver (10); when the rotating speed value of the sensor (8) is equal to the set rotating speed value in the main controller (9), the main controller (9) controls the output shaft of the tensioning motor (4) to stop rotating reversely through the motor driver (10);

the lifting and carriage linkage device also comprises a safety valve (13); the safety valve (13) is arranged on an oil channel from an oil outlet of the hydraulic pump (62) to the oil tank (61);

the lifting and carriage linkage device also comprises a filter (14); the filter (14) is disposed on an oil passage from an oil tank (61) to an oil inlet of a hydraulic pump (62).

2. The dump truck according to claim 1, wherein: the worm wheel is fixedly connected to the rear door, and the circle center of the worm wheel is coaxial with the hinge point 01 of the carriage body and the rear door; the machine body of the tensioning motor is fixedly connected to the mounting frame, and an output shaft of the tensioning motor is in transmission connection with one end of the worm; the worm is rotationally connected to the mounting frame, and the other end of the worm is in transmission connection with the worm wheel to form a worm and gear mechanism; the magnetic ring is fixedly connected to an output shaft of the tensioning motor; the sensor is fixedly connected to the body of the tensioning motor and corresponds to the magnetic ring; the stop block is fixedly connected to the carriage body, and the rear door is limited by the stop block when rotating anticlockwise to an opening position; an execution port A of the manual reversing valve is respectively communicated with a rodless cavity of the lifting oil cylinder and a control port K of the first pressure switch, and an execution port B of the manual reversing valve is respectively communicated with a rod cavity of the lifting oil cylinder and a control port K of the second pressure switch; the first pressure switch, the second pressure switch, the motor driver and the sensor are electrically connected or wirelessly communicated with the main controller; the tensioning motor is electrically connected with the motor driver or in wireless communication connection; when the pressure value of the control port K of the first pressure switch is larger than a first pressure value set in the main controller, the main controller controls the output shaft of the tensioning motor to rotate forwards through the motor driver; when the rotating speed value of the sensor is equal to the set rotating speed value in the main controller, the main controller controls the output shaft of the tensioning motor to stop rotating forwards through the motor driver; when the pressure value of the control port K of the second pressure switch is larger than a second pressure value set in the main controller, the main controller controls the output shaft of the tensioning motor to rotate reversely through the motor driver; when the rotating speed value of the sensor is equal to the set rotating speed value in the main controller, the main controller controls the output shaft of the tensioning motor to stop rotating reversely through the motor driver, so that when the manual reversing valve is operated to enable an oil inlet P of the manual reversing valve to be communicated with the execution port A, pressure oil in the hydraulic pump reaches a rodless cavity of the lifting oil cylinder through the manual reversing valve, a piston rod of the lifting oil cylinder extends out, meanwhile, the pressure oil in the hydraulic pump can also reach a control port K of the first pressure switch through the manual reversing valve, the pressure value of the control port K of the first pressure switch is larger than a first pressure value set in the main controller, the main controller controls the output shaft of the tensioning motor to rotate forwards through the motor driver to drive the worm gear to rotate anticlockwise, the rear door can rotate anticlockwise around a hinge point 01 of the carriage body and the rear door together with the worm gear, and the rear door can.

3. The dump truck according to claim 2, wherein: when the rear door is opened to the opening position, the rear door can not rotate anticlockwise any more, and the worm wheel can not rotate anticlockwise any more, so that the rotating speed of the output shaft of the tensioning motor and the worm is reduced to 0 rpm; the rotation speed value of the sensor is 0rpm, the rotation speed value of the sensor is equal to the set rotation speed value in the main controller, the main controller controls the output shaft of the tensioning motor to stop rotating forwards through the motor driver, and at the moment, the rear door rotates to the opening position from the closing position, namely, the rear door can be automatically opened when the piston rod of the lifting oil cylinder extends out.

4. The dump truck according to claim 3, wherein: when the manual reversing valve is operated to enable an oil inlet P of the manual reversing valve to be communicated with an execution port B, pressure oil in the hydraulic pump reaches a rod cavity of the lifting oil cylinder through the manual reversing valve, a piston rod of the lifting oil cylinder retracts, meanwhile, the pressure oil in the hydraulic pump can also reach a control port K of a second pressure switch through the manual reversing valve, the pressure value of the control port K of the second pressure switch is larger than a second pressure value set in the main controller, the main controller controls an output shaft of the tensioning motor to rotate reversely through a motor driver to drive the worm gear to rotate clockwise, and the rear door can rotate clockwise around a hinge point 01 of the carriage body and the rear door along with the worm gear; thus, the rear door can be automatically closed.

5. The dump truck according to claim 4, wherein: when the rear door is closed to a closed position, the rear door is limited by the compartment body, the rear door cannot rotate clockwise at the moment, and the worm wheel cannot rotate clockwise any more, so that the rotating speed of the output shaft of the tensioning motor and the worm is reduced to 0 rpm; the rotating speed value of the sensor is 0rpm, the rotating speed value of the sensor is equal to the set rotating speed value in the main controller, the main controller controls the output shaft of the tensioning motor to stop rotating reversely through the motor driver, and at the moment, the rear door rotates to the closing position from the opening position, namely, the rear door can be automatically closed when the piston rod of the lifting oil cylinder retracts.