An electric load sensing system and a construction machinery device

Abstract

The present invention provides an electric load sensing system and a construction machinery device. The system consists of a main motor pump source, a pilot motor pump source, a load sensing system, etc. The system uses a variable-speed motor to drive a hydraulic pump, and then supplies oil to the load sensing system. At the same time, a proportional pressure reducing valve is introduced. According to different construction operation requirements, the compensation pressure of the pressure compensation valve is adjusted to change the valve opening-flow correspondence relationship under different operation requirements, so as to improve the controllability during the fine movement process and the speed of the rapid movement. In addition, the motor adopts variable-speed control, combines with the proportional pressure reducing valve to set a target value, and maintains the outlet pressure of the hydraulic pump only higher than the maximum load pressure by the target value set by the proportional pressure reducing valve through pressure compensation control, so as to improve the energy saving of the system.

Description

Technical Field

[0001] The present invention relates to the field of hydraulic systems, and particularly to an electric load sensing system and a construction machinery device. Background Art

[0002] As one of the pillar industries in China, construction machinery plays a crucial role in China's economic construction and social development. However, the traditional construction machinery has gradually been unable to meet the industry development needs due to low energy efficiency, poor emissions, insufficient controllability, etc. Electric construction machinery cancels the engine and uses an electric motor as the driving unit, which has the advantages of zero pollution and low noise, and is considered to be one of the important development trends of construction machinery. At present, however, most electric construction machinery replaces the engine with an electric motor and simulates the working mode of the engine, without fully exerting the good speed regulation and overload characteristics of the electric motor, and the hydraulic system still uses the hydraulic system of the traditional engine-driven construction machinery, resulting in limited system control characteristics and the energy efficiency of the whole machine cannot be maximized.

[0003] In view of this, this application is proposed. Summary of the Invention

[0004] The present invention discloses an electric load sensing system and a construction machinery device, aiming to solve the problems that the control characteristics of the traditional construction machinery hydraulic system are limited and the energy efficiency of the whole machine cannot be maximized.

[0005] The first embodiment of the present invention provides an electric load sensing system, including: a pilot electric pump source, a main electric pump source, a load sensing device, an actuator, a first pressure detection unit, a second pressure detection unit, a third pressure detection unit, a hydraulic oil tank, and a controller;

[0006] Wherein, the first pressure detection unit, the second pressure detection unit, and the third pressure detection unit are electrically connected to the input end of the controller, and the output end of the controller is electrically connected to the input end of the pilot electric pump source and the input end of the main electric pump source;

[0007] Wherein, the output end of the main electric pump source is connected to the actuator through the load sensing device, the output end of the pilot electric pump source is connected to the control end of the load sensing device, and the hydraulic oil tank is connected to the input end of the pilot electric pump source, the input end of the main electric pump source, and the output end of the load sensing device;

[0008] The controller is configured to implement the following steps by executing the computer program stored in its internal memory:

[0009] Obtain the first pressure value at the outlet of the main motor pump source collected by the first pressure detection unit, the second pressure value of the load sensing device collected by the second pressure detection unit, and the third pressure value at the outlet of the pilot motor pump source collected by the third pressure detection unit;

[0010] Invoke the pressure compensation algorithm to control the main motor pump source so that the difference between the first pressure value and the second pressure value is equal to the third pressure value.

[0011] Preferably, the main motor pump source includes: a first motor and a hydraulic pump;

[0012] Wherein, the output shaft of the first motor is connected to the hydraulic pump, the input end of the first motor is electrically connected to the output end of the controller, the input end of the hydraulic pump is connected to the hydraulic oil tank, and the output end of the hydraulic pump is connected to the input end of the load sensing device.

[0013] Wherein, the first pressure detection unit is arranged at the output end of the hydraulic pump.

[0014] Preferably, the pilot motor pump source includes: a second motor, a pilot pump, a proportional pressure reducing valve, and a first safety valve;

[0015] Wherein, the output shaft of the second motor is connected to the pilot pump, the input end of the second motor is electrically connected to the output end of the controller, the input end of the pilot pump is connected to the hydraulic oil tank, the output end of the pilot pump is connected to the input end of the proportional pressure reducing valve, the output end of the proportional pressure reducing valve is connected to the control end of the load sensing device, and the output end of the pilot pump is connected to the hydraulic oil tank through the first safety valve.

[0016] Wherein, the second pressure detection unit is arranged at port B of the throttle orifice.

[0017] Preferably, the load sensing device includes a first pressure compensation valve, a second pressure compensation valve, a first reversing valve, a second reversing valve, a shuttle valve, a second safety valve, a differential pressure reducing valve, and a throttle orifice;

[0018] Port A of the first pressure compensation valve is connected to the control chamber on the right side of the spool of the first pressure compensation valve and port P of the first reversing valve. Port C of the first reversing valve is connected to port A of the shuttle valve and the control chamber on the left side of the spool of the first pressure compensation valve. Port T of the first reversing valve is connected to port T of the second reversing valve and the hydraulic oil tank;

[0019] The port A of the second pressure compensation valve is connected to the right control chamber of the spool of the second pressure compensation valve and the port P of the second reversing valve; the port C of the second reversing valve is connected to the port B of the shuttle valve and the left control chamber of the spool of the second pressure compensation valve;

[0020] The port C of the shuttle valve is connected to the port A of the throttle orifice; the port B of the throttle orifice is connected to the lower control chamber of the differential pressure reducing valve; the port T of the differential pressure reducing valve is connected to the hydraulic oil tank; the port A of the second safety valve is connected to the hydraulic oil tank;

[0021] Wherein, the third pressure detection unit is arranged at the output end of the proportional pressure reducing valve.

[0022] Preferably, the output end of the hydraulic pump is connected to the port P of the first pressure compensation valve, the port P of the second pressure compensation valve, the port P of the second safety valve, the right control chamber of the second safety valve, and the upper control chamber of the differential pressure reducing valve.

[0023] Preferably, the outlet of the proportional pressure reducing valve is connected to the port P of the differential pressure reducing valve.

[0024] Preferably, the port A of the differential pressure reducing valve is connected to the left control chamber of the first pressure compensation valve, the left control chamber of the second pressure compensation valve, and the lower control chamber of the differential pressure reducing valve.

[0025] Preferably, the actuator includes a first actuator oil cylinder and a second actuator oil cylinder;

[0026] The port A of the first reversing valve is connected to the rodless chamber of the first actuator oil cylinder, the port B of the first reversing valve is connected to the rod chamber of the first actuator oil cylinder, the port A of the second reversing valve is connected to the rodless chamber of the second actuator oil cylinder, and the port B of the second reversing valve is connected to the rod chamber of the second actuator oil cylinder.

[0027] The second embodiment of the present invention provides a construction machinery device, which is characterized by including an electric load sensing system as described in any one of the above.

[0028] Based on the electric load sensing system and the construction machinery device provided by the present invention, the controller respectively collects the first pressure value at the outlet of the main motor pump source, the second pressure value of the load sensing device, and the third pressure value at the outlet of the pilot motor pump source through the first pressure detection unit, the second pressure detection unit, and the third pressure detection unit, and controls the main motor pump source through a pressure compensation algorithm so that the difference between the first pressure value and the second pressure value is equal to the third pressure value, solving the problem that the control characteristics of the traditional construction machinery hydraulic system are limited and the energy efficiency of the whole machine cannot be maximized. Description of the Drawings

[0029] Figure 1 This is a schematic structural diagram of an electric load sensing system provided by the present invention;

[0030] Figure 2 This is a schematic diagram of the controller step flow provided by the present invention. Specific Embodiments

[0031] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in 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. Apparently, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention. Therefore, the detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the present invention to be protected, but merely represents selected embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0032] The following provides a detailed description of specific embodiments of the present invention with reference to the accompanying drawings.

[0033] The present invention discloses an electric load sensing system and a construction machinery device, aiming to solve the problems that the control characteristics of the traditional construction machinery hydraulic system are limited and the energy efficiency of the whole machine cannot be maximized.

[0034] Please refer to Figure 1 and Figure 2 , a first embodiment of the present invention provides an electric load sensing system, including: a pilot motor pump source, a main motor pump source, a load sensing device, an actuator, a first pressure detection unit 16, a second pressure detection unit 20, a third pressure detection unit 17, a hydraulic oil tank 19, and a controller;

[0035] Among them, the first pressure detection unit 16, the second pressure detection unit 20, and the third pressure detection unit 17 are electrically connected to the input end of the controller, and the output end of the controller is electrically connected to the input end of the pilot motor pump source and the input end of the main motor pump source;

[0036] Among them, the output end of the main motor pump source is connected to the actuator through the load sensing device, the output end of the pilot motor pump source is connected to the control end of the load sensing device, and the hydraulic oil tank 19 is connected to the input end of the pilot motor pump source, the input end of the main motor pump source, and the output end of the load sensing device;

[0037] The controller is configured to implement the following steps by executing a computer program stored therein:

[0038] Obtain a first pressure value at the outlet of the main motor pump source collected by the first pressure detection unit 16, a second pressure value of the load sensing device collected by the second pressure detection unit 20, and a third pressure value at the outlet of the pilot motor pump source collected by the third pressure detection unit 17;

[0039] Invoke a pressure compensation algorithm to control the main motor pump source so that the difference between the first pressure value and the second pressure value is equal to the third pressure value.

[0040] Preferably, the main motor pump source includes: a first motor 1 and a hydraulic pump 2;

[0041] Wherein, an output shaft of the first motor 1 is connected to the hydraulic pump 2, an input end of the first motor 1 is electrically connected to an output end of the controller, an input end of the hydraulic pump 2 is connected to the hydraulic oil tank 19, and an output end of the hydraulic pump 2 is connected to an input end of the load sensing device.

[0042] Wherein, the first pressure detection unit 16 is disposed at an output end of the hydraulic pump 2.

[0043] Preferably, the pilot motor pump source includes: a second motor 4, a pilot pump 3, a proportional pressure reducing valve 5, and a first safety valve 6;

[0044] Wherein, an output shaft of the second motor 4 is connected to the pilot pump 3, an input end of the second motor 4 is electrically connected to an output end of the controller, an input end of the pilot pump 3 is connected to the hydraulic oil tank 19, an output end of the pilot pump 3 is connected to an input end of the proportional pressure reducing valve 5, an output end of the proportional pressure reducing valve 5 is connected to a control end of the load sensing device, and an output end of the pilot pump 3 is connected to the hydraulic oil tank 19 through the first safety valve 6.

[0045] Wherein, the second pressure detection unit 20 is disposed at an output end of the proportional pressure reducing valve 5.

[0046] Preferably, the load sensing device includes a first pressure compensation valve 7, a second pressure compensation valve 8, a first reversing valve 9, a second reversing valve 10, a shuttle valve 18, a second safety valve 14, a differential pressure reducing valve 13, and an orifice 15;

[0047] The A port of the first pressure compensation valve 7 is connected to the right control chamber of the spool of the first pressure compensation valve 7 and the P port of the first reversing valve 9. The C port of the first reversing valve 9 is connected to the A port of the shuttle valve 18 and the left control chamber of the spool of the first pressure compensation valve 7. The T port of the first reversing valve 9 is connected to the T port of the second reversing valve 10 and the hydraulic oil tank 19.

[0048] The A port of the second pressure compensation valve 8 is connected to the right control chamber of the spool of the second pressure compensation valve 8 and the P port of the second reversing valve 10. The C port of the second reversing valve 10 is connected to the B port of the shuttle valve 18 and the left control chamber of the spool of the second pressure compensation valve 8.

[0049] The C port of the shuttle valve 18 is connected to the A port of the throttle orifice 15. The B port of the throttle orifice 15 is connected to the lower control chamber of the differential pressure reducing valve 13. The T port of the differential pressure reducing valve 13 is connected to the hydraulic oil tank 19. The A port of the second safety valve 14 is connected to the hydraulic oil tank 19.

[0050] Wherein, the third pressure detection unit 17 is arranged at the B port of the throttle orifice 15.

[0051] Preferably, the output end of the hydraulic pump 2 is connected to the P port of the first pressure compensation valve 7, the P port of the second pressure compensation valve 8, the P port of the second safety valve 14, the right control chamber of the second safety valve 14, and the upper control chamber of the differential pressure reducing valve 13.

[0052] Preferably, the outlet of the proportional reducing valve 5 is connected to the P port of the differential pressure reducing valve 13.

[0053] Preferably, the A port of the differential pressure reducing valve 13 is connected to the left control chamber of the first pressure compensation valve 7, the left control chamber of the second pressure compensation valve 8, and the lower control chamber of the differential pressure reducing valve 13.

[0054] Preferably, the actuator includes a first actuator cylinder 11 and a second actuator cylinder 12.

[0055] The A port of the first reversing valve 9 is connected to the rodless chamber of the first actuator cylinder 11. The B port of the first reversing valve 9 is connected to the rod chamber of the first actuator cylinder 11. The A port of the second reversing valve 10 is connected to the rodless chamber of the second actuator cylinder 12. The B port of the second reversing valve 10 is connected to the rod chamber of the second actuator cylinder 12.

[0056] The specific working principle of the present invention is as follows:

[0057] The controller of the construction machinery monitors the signals of the pilot control handle to control the valve opening of the first reversing valve 9. Meanwhile, the outlet pressure of the hydraulic pump 2, the outlet pressure of the proportional pressure reducing valve 5, and the maximum load pressure are respectively monitored by the first pressure detection unit 16, the second pressure detection unit 20, and the third pressure detection unit 17 to control the speed of the first motor 1.

[0058] The operator adjusts the input signal of the proportional pressure reducing valve 5 according to the requirements of earthwork construction operations. When performing fine operations, the amplitude of the input signal of the proportional pressure reducing valve 5 is reduced. When performing fast operations, the amplitude of the input signal of the proportional pressure reducing valve 5 is increased. The pressure compensation pressures of the first pressure compensation valve 7 and the first pressure compensation valve 7 are dynamically adjusted to adjust the valve opening - flow rate correspondence relationship of the first reversing valve 9 and the second reversing valve 10. During the fine operation process, the flow control accuracy of the input signal of the pilot control handle for the first reversing valve 9 and the second reversing valve 10 is improved. During fast operations, the flow control range of the input signal of the pilot control handle for the first reversing valve 9 and the second reversing valve 10 is extended.

[0059] After the system is powered on and working, the controller controls the second motor 4 to drive the pilot pump 3 to work continuously to supply oil to the pilot oil circuit. When the controller monitors the input of the pilot handle signal and it is greater than the control threshold, the controller controls the first motor 1 to rotate to drive the hydraulic pump 2 to supply oil to the main oil circuit. At the same time, the controller controls the valve opening degrees of the first reversing valve 9 and the second reversing valve 10 in a certain proportion according to the magnitude of the input signal of the pilot handle. The hydraulic oil generated by the hydraulic pump 2 flows into the first pressure compensation valve 7, the second pressure compensation valve 8, the first reversing valve 9, and the second reversing valve 10 through the main oil circuit and then flows into the actuator to drive the actuator to act. The pilot oil generated by the pilot pump 3 generates target pressure oil through the proportional pressure reducing valve 5 to control the target compensation pressure of the first pressure compensation valve 7 and the second pressure compensation valve 8. The shuttle valve 18 monitors the maximum load pressure of the actuator and outputs it through the C port of the shuttle valve 18. At the same time, the pressure at the outlet of the hydraulic pump 2 is monitored by the first pressure detection unit, the pressure at the outlet of the proportional pressure reducing valve 5 is monitored by the third pressure detection unit 17, and the pressure of the maximum load is monitored by the second pressure detection unit 20. Through the pressure compensation control algorithm of the first motor 1, the difference between the outlet pressure of the hydraulic pump 2 and the maximum load pressure is equal to the target value of the outlet pressure of the proportional pressure reducing valve 5. At the same time, the pilot oil generated by the pilot pump 3 generates target pressure oil and flows into the differential pressure reducing valve 13 through the proportional pressure reducing valve 5. The C port of the shuttle valve 18 is fed back to the lower control chamber of the differential pressure reducing valve 13. At the same time, a throttle orifice 15 is introduced as a damping orifice in this feedback right path to filter, reducing the influence of drastic load changes on the feedback quantity. At the same time, the outlet pressure of the hydraulic pump 2 is fed back to the upper control chamber of the differential pressure compensation valve. The outlet pressure of the differential pressure reducing valve 13 is fed back to the lower control chamber of the differential pressure reducing valve 13 to achieve target differential pressure filtering of the pressure compensation valve and feed back this signal to the differential pressure compensation valve to control the front and rear valve differential pressures of the first pressure compensation valve 7 and the second pressure compensation valve 8 to be the target control differential pressure.

[0060] Based on the above, the beneficial effects of the embodiment at least include:

[0061] (1) In this embodiment, a motor is used to drive the hydraulic pump 2 to supply oil to the load sensing system. The motor realizes that the difference between the outlet pressure of the hydraulic pump 2 and the maximum load pressure is the target control value through variable speed pressure compensation control.

[0062] (2) In this embodiment, the pilot pump 3 is separated from the main pump and is driven separately by a motor, which can meet the requirement that the main pump stops working when the system idles. When the system resumes work, the main pump motor is quickly started by the motor to respond to the load demand.

[0063] (3) In this embodiment, a proportional pressure reducing valve 5 is used to dynamically adjust the target control pressure of the pressure compensation valve, and the pressure of the pressure compensation valve can be adjusted according to different operation requirements to meet the high controllability under low-speed oil supply and the rapidity of the system under rapid action.

[0064] The second embodiment of the present invention provides a construction machinery device, which is characterized by including an electric load sensing system as described in any one of the above.

[0065] Based on the electric load sensing system and the construction machinery device provided by the present invention, the system is composed of a main motor pump source, a pilot motor pump source, a load sensing system, etc. The system uses a variable speed motor to drive the hydraulic pump 2 to supply oil to the load sensing system. At the same time, a proportional pressure reducing valve 5 is introduced. According to different construction operation requirements, the compensation pressure of the pressure compensation valve is adjusted to change the valve opening-flow correspondence relationship under different operation requirements, and the controllability of the fine movement process and the speed of the fast movement are improved. In addition, the motor adopts variable speed control. Combining with the proportional pressure reducing valve 5 to set the target value, the outlet pressure of the hydraulic pump 2 is maintained only higher than the maximum load pressure by the target value set by the proportional pressure reducing valve 5 through pressure compensation control to improve the energy saving of the system.

[0066] The above are only the preferred embodiments of the present invention, and the protection scope of the present invention is not limited to the above embodiments. All technical solutions falling within the idea of the present invention belong to the protection scope of the present invention.

Claims

1. An electro-hydraulic load sensing system, characterized in that, it includes: a pilot motor pump source, a main motor pump source, a load sensing device, an actuator, a first pressure detection unit, a second pressure detection unit, a third pressure detection unit, a hydraulic oil tank, and a controller; wherein, the first pressure detection unit, the second pressure detection unit, and the third pressure detection unit are electrically connected to the input end of the controller, and the output end of the controller is electrically connected to the input end of the pilot motor pump source and the input end of the main motor pump source; wherein, the output end of the main motor pump source is connected to the actuator through the load sensing device, the output end of the pilot motor pump source is connected to the control end of the load sensing device, and the hydraulic oil tank is connected to the input end of the pilot motor pump source, the input end of the main motor pump source, and the output end of the load sensing device; the controller is configured to implement the following steps by executing a computer program stored therein: acquire a first pressure value at the outlet of the main motor pump source collected by the first pressure detection unit, a second pressure value of the load sensing device collected by the second pressure detection unit, and a third pressure value at the outlet of the pilot motor pump source collected by the third pressure detection unit; invoke a pressure compensation algorithm to control the main motor pump source so that the difference between the first pressure value and the second pressure value is equal to the third pressure value; the main motor pump source includes: a first motor and a hydraulic pump; wherein, the output shaft of the first motor is connected to the hydraulic pump, the input end of the first motor is electrically connected to the output end of the controller, the input end of the hydraulic pump is connected to the hydraulic oil tank, and the output end of the hydraulic pump is connected to the input end of the load sensing device; wherein, the first pressure detection unit is arranged at the output end of the hydraulic pump; the pilot motor pump source includes: a second motor, a pilot pump, a proportional pressure reducing valve, and a first safety valve; wherein, the output shaft of the second motor is connected to the pilot pump, the input end of the second motor is electrically connected to the output end of the controller, the input end of the pilot pump is connected to the hydraulic oil tank, the output end of the pilot pump is connected to the input end of the proportional pressure reducing valve, the output end of the proportional pressure reducing valve is connected to the control end of the load sensing device, and the output end of the pilot pump is connected to the hydraulic oil tank through the first safety valve; the load sensing device includes: a first pressure compensation valve, a second pressure compensation valve, a first reversing valve, a second reversing valve, a shuttle valve, a second safety valve, a differential pressure reducing valve, and an orifice; the port A of the first pressure compensation valve is connected to the control chamber on the right side of the spool of the first pressure compensation valve and the port P of the first reversing valve, the port C of the first reversing valve is connected to the port A of the shuttle valve and the control chamber on the left side of the spool of the first pressure compensation valve, and the port T of the first reversing valve is connected to the port T of the second reversing valve and the hydraulic oil tank; Port A of the second pressure compensation valve is connected to the right control chamber of the spool of the second pressure compensation valve and port P of the second reversing valve; port C of the second reversing valve is connected to port B of the shuttle valve and the left control chamber of the spool of the second pressure compensation valve; Port C of the shuttle valve is connected to port A of the throttle orifice; port B of the throttle orifice is connected to the lower control chamber of the differential pressure reducing valve; port T of the differential pressure reducing valve is connected to the hydraulic oil tank; port A of the second safety valve is connected to the hydraulic oil tank; Wherein, the third pressure detection unit is arranged at the output end of the proportional pressure reducing valve; Wherein, the second pressure detection unit is arranged at port B of the throttle orifice.

2. An electric load sensing system according to claim 1, Characterized in that, The output end of the hydraulic pump is connected to port P of the first pressure compensation valve, port P of the second pressure compensation valve, port P of the second safety valve, the right control chamber of the second safety valve, and the upper control chamber of the differential pressure reducing valve.

3. An electric load sensing system according to claim 2, Characterized in that, The outlet of the proportional pressure reducing valve is connected to port P of the differential pressure reducing valve.

4. An electric load sensing system according to claim 2, Characterized in that, Port A of the differential pressure reducing valve is connected to the left control chamber of the first pressure compensation valve, the left control chamber of the second pressure compensation valve, and the lower control chamber of the differential pressure reducing valve.

5. An electric load sensing system according to claim 2, Characterized in that, The actuator includes a first actuator cylinder and a second actuator cylinder; Port A of the first reversing valve is connected to the rodless chamber of the first actuator cylinder, port B of the first reversing valve is connected to the rod chamber of the first actuator cylinder, port A of the second reversing valve is connected to the rodless chamber of the second actuator cylinder, and port B of the second reversing valve is connected to the rod chamber of the second actuator cylinder.

6. A construction machinery device, Characterized in that, It includes an electric load sensing system according to any one of claims 1 to 5.

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