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CN-122013833-A - Static pressure bulldozer and control method and device thereof

CN122013833ACN 122013833 ACN122013833 ACN 122013833ACN-122013833-A

Abstract

The invention relates to the technical field of engineering machinery and discloses a static pressure bulldozer, a control method and a control device thereof, wherein a LS port of a main valve is communicated with an X port of a working pump in a left position of a switching valve in a working hydraulic system of the static pressure bulldozer, a P port and an X port of the working pump are communicated with a right position of the switching valve, an inlet of a proportional pressure reducing valve is connected with the P port of the working pump, a control output end provides regulating pressure for a controlled space of a controlled switching valve, the controlled switching valve is arranged between the P port and the T port of the main valve, and a conduction state of the controlled switching valve is configured to form throttling resistance between the P port and the T port so as to maintain load pressure required by the system. When the rising speed of the engine speed exceeds the threshold value, the switching valve is automatically switched to the right position to increase the pump displacement, and the proportional pressure reducing valve is regulated to control the controlled switching valve to form controllable throttling resistance, so that the overspeed of the engine and the out-of-control of the executing mechanism can be effectively inhibited under the negative load working conditions such as long downhill and the like.

Inventors

  • XU SHOUJUN
  • SUN DONGDONG
  • MA CHENGZHAO
  • CAO ZHU
  • WU SHAOZE
  • Guan Junsen

Assignees

  • 山东临工工程机械有限公司

Dates

Publication Date
20260512
Application Date
20260122

Claims (10)

  1. 1. A control method of a static pressure bulldozer is applied to a working hydraulic system of the static pressure bulldozer, the working hydraulic system comprises a switching valve (3), a one-way throttle valve (2), a proportional pressure reducing valve (5) and a controlled switching valve (6), a LS port of the main valve (4) is communicated with an X port of a working pump (1) in the left position of the switching valve (3), a P port and an X port of the working pump (1) are communicated in the right position of the switching valve, an inlet of the proportional pressure reducing valve (5) is connected with the P port of the working pump (1), a control output end provides regulating pressure for a controlled space of the controlled switching valve (6), the controlled switching valve (6) is arranged between the P port and the T port of the main valve (4), and the conducting state of the controlled switching valve (6) is configured to form throttling resistance between the P port and the T port so as to maintain load pressure required by the system. When the speed of the engine exceeds a preset first threshold value, generating an flameout prevention enabling signal according to the speed of the engine, and sending the flameout prevention enabling signal to the switching valve (3) to control the switching valve (3) to switch to the right, so that the P port pressure of the working pump (1) is led into the X port of the working pump (1) through the switching valve (3) to regulate the displacement of the working pump (1) to the maximum; And generating a control current signal of the proportional pressure reducing valve (5) according to the rising speed of the engine speed, and sending the control current signal to the proportional pressure reducing valve (5) so that the output pressure of the proportional pressure reducing valve (5) acts on the controlled switch valve (6), and enabling the controlled switch valve (6) to switch and conduct the P port to the T port of the main valve (4).
  2. 2. The method according to claim 1, wherein said generating a proportional pressure reducing valve (5) control current signal in accordance with said rate of engine speed rise comprises: acquiring the current engine speed; Determining the minimum power required for maintaining the stable operation of the engine according to the current engine speed and the preset mapping relation between the engine speed and the minimum power; Calculating a minimum output pressure of the working pump (1) required to provide the minimum power according to the minimum power, the current engine speed, the maximum displacement of the working pump (1) and the transmission efficiency; And determining a target control current value according to the minimum output pressure of the working pump (1) and the preset corresponding relation between the pump output pressure and the control current of the proportional pressure reducing valve (5), and taking the target control current value as a control current signal of the proportional pressure reducing valve (5).
  3. 3. The method according to claim 1, wherein the working hydraulic system further comprises a main valve (4), a lifting oil cylinder (8), an electric control pilot valve (12) and a hydraulic control back pressure valve (9), the hydraulic control back pressure valve (9) is arranged at a T-port oil return position of the main valve (4), an oil inlet is communicated with an oil return passage of the main valve (4), an oil outlet is communicated with a hydraulic oil tank and is provided with a hydraulic control port, the electric control pilot valve (12) is used for controlling the descending action of the lifting oil cylinder (8), the output end is a b2 oil port, and the b2 oil port is connected to the hydraulic control port through a control oil way, and the method further comprises: when a descending instruction of the lifting oil cylinder (8) is received, a current opening signal of the control handle is obtained; generating a corresponding pilot pressure control instruction according to the current opening signal; The pilot pressure control signal is sent to the electric control pilot valve (12) to control the electric control pilot valve (12) to output pilot pressure corresponding to the opening of the control handle to the b2 oil port, so that the pilot pressure of the b2 oil port acts on the hydraulic control port through the control oil way to drive the hydraulic control back pressure valve (9) to reduce the opening of the oil return throttling port and increase the oil return back pressure.
  4. 4. A method according to claim 3, further comprising: when receiving other action instructions except descending of the lifting oil cylinder (8), generating a b2 unloading control signal, and sending the b2 unloading control signal to the electric control pilot valve (12) to control the electric control pilot valve (12) to unload a b2 oil port of the electric control pilot valve, so that the hydraulic control port has no pressure input, and the hydraulic control back pressure valve (9) maintains minimum oil return back pressure.
  5. 5. The method according to claim 3, wherein the hydraulic control back pressure valve (9) is integrated with an oil supplementing one-way valve, an inlet of the oil supplementing one-way valve is communicated with the hydraulic oil tank, an outlet of the oil supplementing one-way valve is communicated with a large cavity oil return passage of the lifting oil cylinder (8), and when the pressure of the large cavity of the lifting oil cylinder (8) is lower than that of the hydraulic oil tank, the oil supplementing one-way valve is automatically opened under the action of pressure difference to conduct the oil supplementing passage from the hydraulic oil tank to the large cavity of the lifting oil cylinder (8).
  6. 6. The control device of the static pressure bulldozer is applied to a working hydraulic system of the static pressure bulldozer, the working hydraulic system further comprises a switching valve (3), a one-way throttle valve (2), a proportional pressure reducing valve (5) and a controlled switching valve (6), an LS port of a main valve (4) is communicated with an X port of a working pump (1) in the left position of the switching valve (3), a P port and an X port of the working pump (1) are communicated in the right position of the switching valve, an oil inlet of the proportional pressure reducing valve (5) is connected with the P port of the working pump (1), an oil outlet outputs control pressure to a control cavity of the controlled switching valve (6), the controlled switching valve (6) is arranged between the P port and the T port of the main valve (4), and the conducting state of the controlled switching valve is configured to form throttling resistance between the P port and the T port so as to maintain load pressure required by the system, and the control device is characterized by comprising: The first control module is used for generating an anti-flameout enabling signal according to the speed of the engine when the speed of the engine exceeds a preset first threshold value, and sending the anti-flameout enabling signal to the switching valve (3) so as to control the switching valve (3) to switch to the right position, so that the P port pressure of the working pump (1) is led into the X port of the working pump (1) through the switching valve (3), and the displacement of the working pump (1) is regulated to the maximum; the second control module is used for generating a proportional pressure reducing valve (5) control current signal according to the rising rate of the engine rotating speed, and sending the proportional pressure reducing valve (5) control current signal to the proportional pressure reducing valve (5) to adjust the output pressure of the proportional pressure reducing valve, wherein the output pressure acts on a control cavity of the controlled switch valve (6), drives the controlled switch valve (6) to be switched to the left position, and conducts the P port to the T port of the main valve (4).
  7. 7. An electronic device, comprising: A memory and a processor, the memory and the processor being communicatively connected to each other, the memory having stored therein computer instructions, the processor executing the computer instructions to perform the control method of the static pressure bulldozer according to any one of claims 1 to 5.
  8. 8. A static pressure bulldozer comprising the electronic device of claim 7.
  9. 9. A computer-readable storage medium having stored thereon computer instructions for causing a computer to execute the control method of the static pressure bulldozer according to any one of claims 1 to 5.
  10. 10. A computer program product comprising computer instructions for causing a computer to perform the control method of a static pressure bulldozer according to any one of claims 1 to 5.

Description

Static pressure bulldozer and control method and device thereof Technical Field The invention relates to the technical field of engineering machinery, in particular to a static pressure bulldozer and a control method and device thereof. Background During the operation of a construction machine such as a bulldozer, particularly in a long downhill or heavy load running situation, a significant negative load is generated on the working device due to the action of gravity. The negative load drives the hydraulic system in reverse through the hydraulic actuator, and mechanical energy is fed back to the hydraulic circuit. In a hydrostatic transmission or pump control system, this portion of the energy may be further transferred to the engine, causing the engine to be counter-towed. When the reverse drag power is large and the system lacks an effective energy absorbing or damping mechanism, the engine speed is abnormally increased due to external input energy, and overspeed phenomenon occurs. The overspeed engine not only can destroy the normal combustion and lubrication conditions, but also can cause serious faults such as galloping, overload of parts, even mechanical damage and the like, and greatly threatens the equipment safety and the personal safety of operators. Disclosure of Invention The invention provides a static pressure bulldozer, a control method and a control device thereof, which are used for solving the problems of potential safety hazard and equipment damage caused by reverse dragging and overspeed of an engine due to negative load in the related technology. In a first aspect, the invention provides a control method of a static pressure bulldozer, which is applied to a working hydraulic system of the static pressure bulldozer, the working hydraulic system comprises a switching valve 3, a one-way throttle valve 2, a proportional pressure reducing valve 5 and a controlled switching valve 6, an LS port of a main valve 4 communicated with an X port of a working pump 1 on the left side of the switching valve 3 and a P port and an X port of the working pump 1 on the right side of the switching valve 3 are communicated, an inlet of the proportional pressure reducing valve 5 is connected with the P port of the working pump 1, a control output end provides regulating pressure for a controlled space of the controlled switching valve 6, the controlled switching valve 6 is arranged between the P port and the T port of the main valve 4, the conduction state of the controlled switching valve is configured to form throttling resistance between the P port and the T port so as to maintain the required load pressure of the system, and the control method of the static pressure bulldozer comprises the steps of generating an anti-flameout enabling signal according to the rising rate of the engine speed, transmitting the anti-flameout enabling signal to the switching valve 3 to the right side of the switching valve 1, leading the pressure of the P port of the working pump 1 to the working pump to the controlled by the switching valve 1 to the P port through the switching valve 3, leading the pressure of the P port to the working pump 1 to the controlled by the X port to the controlled valve 6 to the controlled by the current, and leading the current to the controlled valve to the greatest degree to the switching valve 5 to the switching valve to the control the pressure 5 when the speed is controlled by the rising rate of the speed of the rotating speed of the engine to be greater than the first threshold. According to the control method of the static pressure bulldozer, the rising rate of the rotating speed of the engine is monitored in real time, and when the rising rate exceeds a preset first threshold value, an overspeed prevention mechanism is triggered timely, so that on one hand, the switching valve 3 is controlled to be switched to the right position, the pressure of the port of the working pump 1P is led into the port X, the displacement of the working pump is forced to be increased to the maximum, the capacity of the system for absorbing negative load energy is enhanced, on the other hand, the output pressure of the proportional reducing valve 5 is dynamically regulated according to the change of the rotating speed, and the controlled switching valve 6 is driven to conduct a small opening throttling channel from the port P of the main valve 4 to the port T, so that controllable oil return resistance is formed. The scheme can effectively inhibit the runaway of the actuating mechanism and overspeed of the engine under the working conditions of long downhill slope and the like, and is only started when abnormal, so that the energy loss of fixed back pressure is avoided, and the safety and the efficiency are both considered. In some alternative embodiments, generating the proportional pressure reducing valve 5 control current signal according to the engine speed rising rate includes obtaining a current engine spe