Electric control pilot device and control method thereof

Abstract

The invention belongs to the technical field of engineering machinery, and particularly relates to an electric control pilot device and a control method thereof.The electric control pilot device comprises a power source, a pressure sensing assembly, a controller and a constant delivery pump assembly, the power source comprises a battery pack, and the pressure sensing assembly comprises a first pressure sensor and a second pressure sensor; the first pressure sensor and the second pressure sensor are used for collecting the pressure value of the pilot hydraulic system and the pressure value of the working hydraulic system respectively, and the controller is used for receiving signals of the pressure sensing assembly and comparing the pressure value collected by the pressure sensing assembly with a preset pressure value in the controller. And the constant displacement pump assembly is coaxially connected with the motor, can be driven by the motor to rotate, and can adjust the flow of hydraulic oil entering the valve assembly according to the change of the rotating speed of the motor. The method has the advantages of being easy to implement, high in element universality, low in cost, low in oil consumption, capable of saving energy, good in anti-pollution performance and the like.

Description

Technical Field

[0001] The present invention belongs to the technical field of construction machinery, and particularly relates to an electronically controlled pilot device and a control method thereof. Background Art

[0002] Fixed-displacement pumps are widely used in construction machinery. A fixed-displacement pump is generally directly connected to a diesel engine or indirectly connected through a gearbox, and most of the valves used in conjunction with the fixed-displacement pump are of the open-centered type. In this traditional usage mode, since the displacement of the pump remains constant, the flow rate output by the pump is only proportional to the engine speed. Many construction machinery operate at a fixed speed, so the flow rate output by the pump is constant. In order to control the speed of the working device, the method of adjusting the opening of the open-centered valve core is often adopted, so that part of the oil enters the cylinder of the working device, and part of the oil flows back to the fuel tank through the throttling of the valve port. This causes the oil flowing back to the fuel tank to consume energy in vain, not only increasing energy consumption, but also increasing the heat generation of the hydraulic system.

[0003] In order to save energy and reduce emissions, construction machinery is also vigorously developing new energy whole machines, and new energy whole machines equipped with battery packs use electric motors to drive hydraulic pumps. If the opening of the valve port can be associated with the speed of the electric motor, that is, when the valve port opening is larger, the electric motor speed is higher, and when the valve port opening is smaller, the electric motor speed is lower, and the hydraulic pump still uses a fixed-displacement pump to provide oil source for the hydraulic system. Then, although the hydraulic system is a fixed-displacement pump system, it can achieve the functions of a variable-displacement pump system, thereby greatly reducing the manufacturing cost. At the same time, because the gear pump and the corresponding open-centered valve core have strong anti-pollution ability for the hydraulic system, hydraulic failures caused by the cleanliness of the oil in the system will also be significantly reduced. Summary of the Invention

[0004] The purpose of the present invention is to solve the defects and deficiencies in the prior art, and provide an electronically controlled pilot device and a control method thereof.

[0005] To achieve the above purpose, the technical solution adopted by the present invention is: an electronically controlled pilot device, comprising: A power source, the power source includes a battery pack; A pressure sensing assembly, the pressure sensing assembly includes a first pressure sensor and a second pressure sensor, and the first pressure sensor and the second pressure sensor are respectively used to collect the pressure value of the pilot hydraulic system and the pressure value of the working hydraulic system; A controller, the controller is used to receive the signal of the pressure sensing assembly, compare the pressure value collected by the pressure sensing assembly with the preset pressure value in the controller, and control the motor speed according to the comparison result; A fixed-displacement pump assembly, the fixed-displacement pump assembly is coaxially connected with the motor, can rotate under the drive of the motor, and can adjust the flow rate of the hydraulic oil entering the valve assembly according to the change of the motor speed.

[0006] Preferably, the metering pump assembly includes a hydraulic pilot pump and a hydraulic working pump, and the suction ports of the hydraulic pilot pump and the hydraulic working pump are both connected to the hydraulic oil tank.

[0007] Preferably, the valve assembly includes a pilot valve and a hydraulic control valve. The inlet ports of the pilot valve and the hydraulic control valve are respectively connected to the outlet ports of the hydraulic pilot pump and the hydraulic working pump. An overflow valve is further provided between the outlet port of the hydraulic working pump and the inlet port of the hydraulic control valve. The working port of the pilot valve is connected to the control port of the hydraulic control valve, and the outlet port of the hydraulic control valve is connected to the hydraulic cylinder.

[0008] Preferably, the first pressure sensor is arranged between the working port of the pilot valve and the control port of the hydraulic control valve, and the second pressure sensor is arranged on the overflow valve.

[0009] Preferably, the controller is configured to implement the following steps by executing the control program stored therein: Obtain the pressure signals collected by the pressure sensing assembly; First, determine whether the pressure value collected by the first pressure sensor is greater than zero. If it is greater than zero, then determine whether it is greater than the preset pilot hydraulic system pressure value in the controller; Then, determine whether the pressure value collected by the second pressure sensor is greater than the preset working hydraulic system pressure value in the controller; Based on different judgment results, control the motor speed to the corresponding speed through the preset minimum motor speed, maximum motor speed and pressure-speed mapping relationship in the controller.

[0010] A control method for an electronically controlled pilot device includes: The pressure value collected by the first pressure sensor and the pressure value collected by the second pressure sensor are fed back to the controller; If the pressure value collected by the first pressure sensor is zero, regardless of the magnitude of the pressure value collected by the second pressure sensor, the controller outputs a control signal to adjust the motor speed to zero; If the pressure value collected by the first pressure sensor is greater than the preset pilot hydraulic system pressure value in the controller, continue to compare whether the pressure value collected by the second pressure sensor is greater than the preset working hydraulic system pressure value in the controller. If it is greater, the controller outputs a control signal to adjust the motor speed to the minimum speed. If it is not greater, the controller detects whether the motor speed reaches the maximum speed and controls the motor speed to remain at the maximum speed; If the pressure value collected by the first pressure sensor is greater than zero and not greater than the preset pilot hydraulic system pressure value in the controller, continue to compare whether the pressure value collected by the second pressure sensor is greater than the preset working hydraulic system pressure value in the controller. If it is greater, the controller outputs a control signal to adjust the motor speed to the minimum speed. If it is not greater, the motor speed is controlled to the motor speed corresponding to the pressure-speed mapping relationship through the preset pressure-speed mapping relationship in the controller.

[0011] Preferably, the method of controlling the motor speed to the motor speed corresponding to the pressure-speed mapping relationship through the preset pressure-speed mapping relationship in the controller is as follows: When the pressure value collected by the first pressure sensor is greater than zero and not greater than the preset pilot hydraulic system pressure value in the controller, and at the same time the pressure value collected by the second pressure sensor is not greater than the preset working hydraulic system pressure value in the controller, at this time, the motor speed target value corresponding to the pressure-speed mapping relationship is determined according to the pressure value collected by the first pressure sensor, and the motor speed is controlled to the motor speed corresponding to the pressure-speed mapping relationship according to the motor speed target value.

[0012] After adopting the above technical solutions, an electronic control pilot device and its control method provided by the present invention have the following beneficial effects: The present invention can enable the quantitative pump open circuit system to achieve throttling speed regulation while achieving volume speed regulation, and has the ability to reduce the pump flow to the minimum flow instantaneously during high-pressure overflow to meet the lubrication and internal leakage of the system. It can fully possess the performance characteristics and energy-saving advantages of a load-sensitive system composed of a variable pump and a variable valve. At the same time, its component cost is much lower than that of a variable pump and a variable valve, and its anti-pollution ability is much better than that of a load-sensitive system composed of a variable pump and a variable valve. Therefore, the present invention is a preferred hydraulic system solution with a battery power source, and has the advantages of easy implementation, strong component versatility, low cost, low fuel consumption, energy saving, and good anti-pollution performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 is the hydraulic schematic diagram of an electronic control pilot device of the present invention; Figure 2 is the control method flow block diagram of an electronic control pilot device of the present invention.

[0014] Wherein: controller 1, first pressure sensor 2, pilot valve 3, hydraulic cylinder 4, hydraulic control valve 5, overflow valve 6, hydraulic working pump 7, hydraulic pilot pump 8, motor 9, hydraulic oil tank 10, second pressure sensor 11. DETAILED DESCRIPTION OF THE INVENTION

[0015] The present invention will be further clearly and completely described below in conjunction with the accompanying drawings and specific embodiments. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all embodiments. The following description of at least one exemplary embodiment is actually only illustrative and in no way limits the present invention or its application or use. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts belong to the scope of protection of the present invention.

[0016] As Figure 1 shown, an electro-control pilot device provided by the present invention includes a power source, a pressure sensing assembly, a controller 1, a motor 9, a fixed-displacement pump assembly, a valve assembly, and a hydraulic oil tank 10. The power source includes a battery pack. The pressure sensing assembly includes a first pressure sensor 2 and a second pressure sensor 11. The first pressure sensor 2 and the second pressure sensor 11 are respectively used to collect the pressure values of the pilot hydraulic system and the working hydraulic system. The input end of the controller 1 is electrically connected to the output end of the pressure sensing assembly, and the output end of the controller 1 is connected to the motor 9. That is, the controller 1 is used to receive the signals of the pressure sensing assembly, compare the pressure values collected by the pressure sensing assembly with the preset pressure values in the controller 1, and can control the rotation speed of the motor 9 according to the comparison result. The fixed-displacement pump assembly includes a hydraulic pilot pump 8 and a hydraulic working pump 7. The hydraulic pilot pump 8 and the hydraulic working pump 7 are mechanically connected coaxially with the motor 9. That is, the hydraulic pilot pump 8 and the hydraulic working pump 7 can rotate driven by the motor 9 and can adjust the hydraulic oil flow rate into the valve assembly according to the change of the rotation speed of the motor 9. The valve assembly includes a pilot valve 3, a hydraulic control valve 5, and a relief valve 6. The suction ports of the hydraulic pilot pump 8 and the hydraulic working pump 7 are both connected to the hydraulic oil tank 10. The oil outlet of the hydraulic working pump 7 is connected to both the oil inlet of the hydraulic control valve 5 and the oil inlet of the relief valve 6. The oil outlet of the hydraulic control valve 5 is connected to the hydraulic cylinder 4, and the oil return port is connected to the hydraulic oil tank 10. Specifically, the A and B ports of the hydraulic control valve 5 are respectively connected to the large and small chambers of the hydraulic cylinder 4. The oil outlet of the hydraulic pilot pump 8 is connected to the oil inlet of the pilot valve 3. The oil return port of the pilot valve 3 is connected to the hydraulic oil tank 10. The working port of the pilot valve 3 is connected to the control port of the hydraulic control valve 5. Specifically, the a1 and a2 ports of the pilot valve 3 are respectively connected to the V1 and V2 ports of the hydraulic control valve 5. There are two first pressure sensors 2, which are respectively arranged between the a1 port and the V1 port, and between the a2 port and the V2 port. The pressure value collected by any one of the first pressure sensors 2 at the a1 port or the a2 port is the pressure value Pi of the pilot hydraulic system. The second pressure sensor 11 is arranged on the relief valve 6. The pressure value collected by the second pressure sensor 11 is the pressure value Pj of the working hydraulic system.

[0017] The controller is configured to implement the following steps by executing the control program stored therein: Preset the pressure value P1 of the pilot hydraulic system and the pressure value P2 of the working hydraulic system in the controller 1, and preset the minimum motor speed Nmin, the maximum motor speed Nmax, and the pressure-speed mapping relationship; Obtain the pressure signal collected by the pressure sensing component; First, determine whether the pressure value Pi collected by the first pressure sensor 2 is greater than zero. If it is greater than zero, then determine whether it is greater than the preset pressure value P1 of the pilot hydraulic system in the controller 1; Then, determine whether the pressure value Pj collected by the second pressure sensor 11 is greater than the preset pressure value P2 of the working hydraulic system in the controller 1; Based on different judgment results, control the speed of the motor 9 to the corresponding speed through the preset minimum motor speed Nmin, the maximum motor speed Nmax, and the pressure-speed mapping relationship in the controller 1.

[0018] As Figure 2 shown, the present invention also provides a control method for an electronically controlled pilot device for the above-mentioned electronically controlled pilot device, including: The first pressure sensor 2 and the second pressure sensor 11 respectively collect the pilot hydraulic system pressure value Pi and the working hydraulic system pressure value Pj under the action of the control handle; The controller 1 obtains the pressure value Pi collected by the first pressure sensor 2 and the pressure value Pj collected by the second pressure sensor 11; The controller 1 determines whether the pressure value Pi collected by the first pressure sensor 2 is greater than zero. If the pressure value Pi collected by the first pressure sensor 2 is zero, then regardless of the magnitude of the pressure value Pj collected by the second pressure sensor 11, the controller 1 outputs a control signal to adjust the speed of the motor 9 to zero; The controller 1 determines whether the pressure value Pi collected by the first pressure sensor 2 is greater than the preset pressure value P1 of the pilot hydraulic system in the controller 1. If the pressure value Pi collected by the first pressure sensor 2 is greater than the preset pressure value P1 of the pilot hydraulic system in the controller 1, continue to compare whether the pressure value Pj collected by the second pressure sensor 11 is greater than the preset pressure value P2 of the working hydraulic system in the controller 1. If it is greater, then the controller 1 outputs a control signal to adjust the speed of the motor 9 to the set minimum speed Nmin. If it is not greater, then the controller 1 detects whether the speed of the motor 9 reaches the set maximum speed Nmax. If it has not reached, then control the speed of the motor 9 to be adjusted to the maximum speed Nmax. If it has reached, then control the speed of the motor 9 to remain at the maximum speed Nmax; If the pressure value Pi collected by the first pressure sensor 2 is greater than zero and not greater than the preset pilot hydraulic system pressure value P1 in the controller 1, continue to compare whether the pressure value Pj collected by the second pressure sensor 11 is greater than the preset working hydraulic system pressure value P2 in the controller 1. If it is greater, the controller 1 outputs a control signal to adjust the motor 9 speed to the set minimum speed Nmin. If it is not greater, the motor 9 speed is controlled to the motor speed corresponding to the pressure-speed mapping relationship through the preset pressure-speed mapping relationship in the controller 1.

[0019] Specifically, the method of controlling the motor 9 speed to the motor speed corresponding to the pressure-speed mapping relationship through the preset pressure-speed mapping relationship in the controller 1 is as follows: When the pressure value Pi collected by the first pressure sensor 2 is greater than zero and not greater than the preset pilot hydraulic system pressure value P1 in the controller 1, and at the same time the pressure value Pj collected by the second pressure sensor 11 is not greater than the preset working hydraulic system pressure value P2 in the controller 1, at this time, the motor speed target value Ni corresponding to the pressure-speed mapping relationship is determined according to the pressure value Pi collected by the first pressure sensor 2, and the motor 9 speed is controlled to the motor speed corresponding to the pressure-speed mapping relationship according to the motor speed target value Ni.

[0020] Further, that is, when the pressure value range collected by the first pressure sensor 2 is [0, Pi], where Pi is not greater than the preset pilot hydraulic system pressure value P1 in the controller 1, and the pressure value Pj collected by the second pressure sensor 11 is not greater than the preset working hydraulic system pressure value P2 in the controller 1, the corresponding speed of the motor 9 is [0, Ni].

[0021] In summary, an electro-control pilot device and its control method of the present invention can enable the quantitative pump open-loop system to achieve volume speed regulation while achieving throttle speed regulation, and have the pump flow reduced to the minimum flow at the moment of high-pressure overflow to meet the lubrication and internal leakage of the system. It can fully possess the performance characteristics and energy-saving advantages of the load-sensing system composed of variable pumps and variable valves. At the same time, its component cost is much lower than that of variable pumps and variable valves, and its anti-pollution ability is much better than that of the load-sensing system composed of variable pumps and variable valves. Therefore, the present invention is a preferred hydraulic system solution with a battery power source, and has the advantages of easy implementation, strong component versatility, low cost, low fuel consumption, energy saving, and good anti-pollution performance.

[0022] The above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution and inventive concept of the present invention, makes equivalent substitutions or changes, and should be covered by the protection scope of the present invention.

Claims

1. An electric pilot device, characterized in that: include: A power source, the power source comprising a battery pack; A pressure sensing assembly, the pressure sensing assembly comprising a first pressure sensor and a second pressure sensor, the first pressure sensor and the second pressure sensor being used to collect a pressure value of a pilot hydraulic system and a pressure value of a working hydraulic system, respectively; A controller, the controller is used to receive a signal from the pressure sensor assembly, compare the pressure value collected by the pressure sensor assembly with a preset pressure value in the controller, and control the motor speed according to the comparison result; The metering pump assembly is coaxially connected to the motor, can rotate under the drive of the motor, and can adjust the flow of hydraulic oil entering the valve assembly according to the change of the motor speed.

2. An electric control pilot device according to claim 1, characterized in that: The quantitative pump assembly comprises a hydraulic pilot pump and a hydraulic working pump, and the oil suction ports of the hydraulic pilot pump and the hydraulic working pump are both connected to the hydraulic oil tank.

3. An electric control pilot device according to claim 2, characterized in that: The valve assembly includes a pilot valve and a hydraulic control valve, the oil inlets of the pilot valve and the hydraulic control valve are respectively connected to the oil outlets of the hydraulic pilot pump and the hydraulic working pump, an overflow valve is also provided between the oil outlet of the hydraulic working pump and the oil inlet of the hydraulic control valve, the working port of the pilot valve is connected to the control port of the hydraulic control valve, and the oil outlet of the hydraulic control valve is connected to the hydraulic cylinder.

4. An electric control pilot device according to claim 3, characterized in that: The first pressure sensor is arranged between the working port of the pilot valve and the control port of the hydraulic control valve, and the second pressure sensor is arranged on the relief valve.

5. The electric pilot device according to claim 1, characterized in that: The controller is configured to implement the following steps by executing a control program stored therein: Acquiring a pressure signal collected by the pressure sensing component; First, determine whether the pressure value collected by the first pressure sensor is greater than zero. If it is greater than zero, determine whether it is greater than the pilot hydraulic system pressure value preset in the controller; Then, it is determined whether the pressure value collected by the second pressure sensor is greater than the working hydraulic system pressure value preset in the controller; Based on different judgment results, the motor speed is controlled to the corresponding speed through the preset motor minimum speed, motor maximum speed and pressure-speed mapping relationship in the controller.

6. A control method for an electric pilot device according to any one of claims 1 to 5, characterized in that: include: The pressure value collected by the first pressure sensor and the pressure value collected by the second pressure sensor are fed back to the controller; If the pressure value collected by the first pressure sensor is zero, then regardless of the pressure value collected by the second pressure sensor, the controller outputs a control signal to adjust the motor speed to zero; If the pressure value collected by the first pressure sensor is greater than the pilot hydraulic system pressure value preset in the controller, continue to compare whether the pressure value collected by the second pressure sensor is greater than the working hydraulic system pressure value preset in the controller. If it is greater, the controller outputs a control signal to adjust the motor speed to the minimum speed. If it is not greater, the controller detects whether the motor speed reaches the maximum speed and controls the motor speed to remain at the maximum speed. If the pressure value collected by the first pressure sensor is greater than zero and not greater than the pilot hydraulic system pressure value preset in the controller, continue to compare whether the pressure value collected by the second pressure sensor is greater than the working hydraulic system pressure value preset in the controller. If it is, the controller outputs a control signal to adjust the motor speed to the minimum speed. If it is not, the motor speed is controlled to the motor speed corresponding to the pressure-speed mapping relationship through the pressure-speed mapping relationship preset in the controller.

7. A control method for an electric pilot device according to claim 6, characterized in that: The method of controlling the motor speed to the motor speed corresponding to the pressure-speed mapping relationship is as follows: When the pressure value collected by the first pressure sensor is greater than zero and not greater than the pilot hydraulic system pressure value preset in the controller, and at the same time the pressure value collected by the second pressure sensor is not greater than the working hydraulic system pressure value preset in the controller, at this time, the motor speed target value corresponding to the pressure-speed mapping relationship is determined according to the pressure value collected by the first pressure sensor, and the motor speed is controlled to be adjusted to the motor speed corresponding to the pressure-speed mapping relationship according to the motor speed target value.

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