[0019] The preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings to be more readily understood by those skilled in the art, so that the scope of the invention is more clearly defined.
[0020] See figure 1 A excavator-based electric arm energy recovery system based on a pressure variable excavator, mainly including excavating motor arms control moieties and energy recovery portions. The boom control unit is mainly made of a tank 1, a relief valve 2, a hydraulic variable pump 3, an engine 4, a three-way four-way reversing valve 5, which can adjust the flow valve 6, a hydraulic one-way valve 7, a first pressure sensor 8, and The arm cylinder 9, the controller 23, the energy recovery portion is mainly mainly by the switching valve 11, the piston accumulator 12, the pneumatic servo valve 13, the second pressure sensor 14, the third pressure sensor 15, the fourth pressure sensor 16, first The pneumatic one-way valve 17, the second air-moving valve 18, the high pressure gas tank 19, the low pressure gas tank 20, the air pump 21, the clutch 22 composition.
[0021] The relief valve 2 is connected to the hydraulic variable motor 3, that is, the inlet of the overflow valve 2 is connected to the outlet of the variable hydraulic pump 3, and the outlet of the relief valve 2 is connected to the inlet of the variable hydraulic pump 3; three four-way commutation valve 5 The oil port P is connected to the outlet of the hydraulic variable pump 3, and the oil port T is connected to the tank 1, and the fuel port A and the hydraulic one-way valve of the triple four-way reversing valve 5 are connected. 7 of the inlet, the outlet of the hydraulic one-way valve 7 is connected to the non-rod cavity of the boom cylinder 9; the adjustable flow valve 6 is connected in parallel with the hydraulic unidirectional valve 7; the first pressure sensor 8 is The hydraulic pressure sensor is connected to the rod-free end of the boom cylinder 9; the switch valve 11 is two-position two-way electric control switch valve, which is connected to the oil port of the piston accumulator 12; pneumatic servo valve 13 For the three four-way pneumatic commutation valve, the air port of the piston accumulator 12 is simultaneously connected with the two air ports of the pneumatic servo valve 13, and the air port A end of the high-pressure storage tank and the first pneumatic single-way valve 17 The intake port is connected, the air port of the first pneumatic single-way valve 17 is connected to the first intake port of the pneumatic servo valve 13; the intake port A end of the low pressure gas tank 20 and the second aerodynamic single direction valve 18 The air port is connected, the air port of the second air movable single direction is connected to the other intake port of the pneumatic servo valve 13; the intake port B of the high pressure gas tank 19 is connected to the air pump 21, the low pressure gas tank 20 The air port B end is connected to the intake port of the air pump 21, and the second pressure sensor 14 is connected to the charge and discharge port of the piston type accumulator 12, and the third pressure sensor 15 is connected to the air-contact A terminal of the high pressure gas storage tank 19. The fourth pressure sensor 16 is connected to the intake port A terminal of the low pressure gas tank 20, and the input shaft of the air pump 21 is connected to the output shaft of the engine 4 via the clutch 22.
[0022] The variable hydraulic pump 3 is a state in which the boom cylinder 9 is supplied by the three four-pass reversing valve 5, and the three four-way commutation valve 5 and the switch valve 11 controls the state of the boom cylinder 9: when the boom is rising The variable hydraulic pump 3 and the piston accumulator 12 are commonly used as the rod-free oil supply of the dynamic arm oil cylinder 9; when the boom is lowered, the variable hydraulic pump 3 is a rod cavity oil supply, an electric arm cylinder. 9 The non-rod high pressure oil flows into the piston accumulator 12; the hydraulic one-way valve 7 is to prevent the high pressure oil flow to return the fuel tank 1 when recovering energy, and the pressure of the arm oil cylinder 9 is not available. When the adjustable flow valve 6 is opened, the arm oil cylinder 9 has a non-rod oil fluid flow back to the fuel tank 1.
[0023] The switch valve 11 is configured to control the charging and discharge of the piston accumulator 12, the first pressure sensor 8 monitors the rod-like pressure of the boom oil cylinder 9, and the second pressure sensor 14 is used to monitor the piston accumulator 12. The gas cavity pressure, the third pressure sensor 15 is used to monitor the gas pressure of the high-pressure storage tank 19, and the fourth pressure sensor 16 is used to monitor the gas pressure of the low-pressure storage tank 20, and the pneumatic servo valve 13 is used to control high-pressure storage tank 19. The gas chamber of the piston accumulator 12 is inflated to the low-pressure storage tank 20, and the gas pump 21 is used to pump the gas in the low-pressure storage tank 20 into the high pressure gas storage tank 19. The engine 4 drives the start and stop of the air pump 21.
[0024] The piston accumulator 12, the high-pressure gas storage tank 19, the low pressure gas tank 20 were pre-charged before the start of the work, and the inflation pressure of the piston accumulator 12 was slightly smaller than the boom 10 on the arm oil cylinder 9. The minimum pressure, the pre-charge pressure of the high pressure gas tank 19 should satisfy the pressure generated by the load and the boom 10 on the movable arm of the boom in most working conditions is smaller than the gas cavity when the piston type accumulator 12 is zero in the internal oil. When the gas pressure of the gas and the high pressure gas tank 19, the gas pressure of the low pressure gas tank 20, the pre-charge pressure of the low pressure gas tank 20 should satisfy the pressure generated by the boom 10 on the arm oil cylinder 9, which is greater than when the piston The gas in the gas chamber of the accumulator 12 is pressed into the gas pressure when the low-pressure storage tank 20 is pressed.
[0025] The clutch 22 is configured to connect the air pump 21 to the engine 4 when the engine 4 is low, pump the gas in the low-pressure storage tank 20 into the high pressure gas storage tank 19. The relief valve 2 is used to overflow protection when the system is too high.
[0026] In the system, all pressure sensors and pneumatic servo valves require a faster response speed to meet the control function.
[0027] work process:
[0028] When the three four-way reversing valve 5 is turned on, the boom is lowered, the first pressure sensor 8 monitors the rod pressure pressure of the boom oil cylinder 9 in real time, the second pressure sensor 14 monitors the piston accumulator 12 gas cavity. The pressure, the third pressure sensor 15 monitors high-pressure storage tank 19 in real time, the fourth pressure sensor 16 monitors the pressure of the low-pressure storage tank 20 in real time, and will result in the following four states:
[0029]State 1: When the arm oil cylinder 9 has a rod pressure lower than the piston type accumulator 12 gas pressure and is higher than the pressure in which the gas in the piston type accumulator 12 is mixed with the low pressure gas tank 20, at this time In the energy recovery state, the adjustable flow valve 6 is closed, the switch valve 11 is applied, the pneumatic servo valve 13 is electrically connected to control the gas portion in the piston type accumulator 12 into the low-pressure storage tank 20, by controlling the piston type energy storage. The pressure of the inner gas in the device 12 is balanced the arm oil cylinder 9 with a rod cavity, and the control boom is lowered. In this state, when the gas pressure in the low-pressure storage tank 20 is higher than the preset pressure, the clutch 22 is insembled, the air pump 21 operates, and the gas in the low-pressure storage tank 20 is pumped into the high pressure gas tank 19, when low pressure When the gas tank 20 is equal to or lower than the preset pressure, the clutch 22 is turned off, and the air pump 21 stops working;
[0030] State 2: When the arm oil cylinder 9 has a rod pressure higher than the piston type accumulator 12 gas pressure and below the pressure of the gas in the piston type accumulator 12 and the pressure in which the gas in the high pressure gas tank 19 is mixed, at this time In the energy recovery state, the adjustable flow valve 6 is closed, the switch valve 11 is applied, the pneumatic servo valve 13 is applied to control the gas portion in the high-pressure storage tank 19 into the piston accumulator 12, by controlling the piston energy storage. The pressure of the inner gas in the device 12 is balanced the arm oil cylinder 9 with a rod cavity, and the control boom is lowered. In this state, when the gas pressure in the high-pressure storage tank 19 is lower than the preset pressure, the clutch 22 is insembled, the gas pump 21 operates, and the gas in the low-pressure gas tank 20 is pumped into the high pressure gas tank 19, when high pressure When the gas tank 19 is equal to or higher than the preset pressure, the clutch 22 is turned off, and the air pump 21 stops working;
[0031] State three: When the arm oil cylinder 9 has a rod-free pressure higher than the piston type accumulator 12 gas pressure and is higher than the pressure of the gas in the piston type accumulator 12 and the high pressure gas tank 19, the gas is in communication with the high pressure gas tank 19. The power recovery system is not dried, and the energy cannot be recovered, the switch valve 11 is discharged, the throttle flow 6 is opened, and the changer arm decreases by adjusting the valve opening area of the adjustable flow valve 6;
[0032] State 4: When the arm oil cylinder 9 has a rod pressure lower than the piston accumulator 12 gas pressure and below the pressure of the gas in the piston type accumulator 12 and the gas in the low pressure gas tank 20, at this time, The boom cylinder 9 has a rod-like hydraulic oil due to small pressure, and cannot be pressed into the piston type accumulator 12. Therefore, the energy cannot be recovered, the switching valve 11 is discharged, the throttle flow 6 is opened, by adjusting the valve adjustable flow valve 6 The mouth area is to control the boom drop.
[0033] When the three four-way reversing valve 5 is turned on, the boom is rising, the adjustable flow valve 6 is closed, the first pressure sensor 8 monitors the rod-resistant pressure of the boom cylinder 9 in real time, the second pressure sensor 14 monitors the piston in real time. The gas accumulator 12 gas cavity pressure, the third pressure sensor 15 monitors the high-pressure storage tank 19 in real time, the fourth pressure sensor 16 monitors the pressure of the low-pressure storage tank 20 in real time, will result in the following four states:
[0034] State 1: When the brach arm oil cylinder 9 has a rod pressure higher than the piston type accumulator 12 pressure and higher than the pressure of the gas in the piston type accumulator 12 and the high pressure storage tank 19, the energy is in this time. The recovered portion cannot release energy on the boom oil cylinder 9, so the switching valve 11 is out of charge, and the boom rising by adjusting the displacement of the variable hydraulic pump 3;
[0035] State 2: When the arm oil cylinder 9 has a rod pressure higher than the piston type accumulator 12 pressure but below the pressure of the gas body in the piston type accumulator 12 and the high pressure gas storage tank 19, the energy is in this time. The recovery portion can release energy on the boom oil cylinder 9, so that the valve 11 is applied, the pneumatic servo valve 13 is applied to control the high pressure gas in the high-pressure storage tank 19 into the piston accumulator 12, by controlling the piston The 12 gas cavity pressure is controlled to control the boom rising;
[0036] State three: When the arm oil cylinder 9 has a rod pressure lower than the piston accumulator 12 pressure but is higher than the pressure in which the gas in the piston type accumulator 12 is mixed with the low pressure gas tank 20, at this time, energy The recovered portion can release energy on the boom oil cylinder 9, so that the valve 11 is applied, the pneumatic servo valve 13 is electrically, control the piston accumulator 12 gas lumen gas into the high pressure gas storage tank 19, by controlling the piston The 12 gas cavity pressure is controlled to control the boom rising;
[0037] State 4: When the arm oil cylinder 9 has a rod-free pressure lower than the piston type accumulator pressure and below the pressure of the gas in the piston type accumulator 12 and the gas in the low pressure gas tank 20, the energy recovery is at this time. The portion does not release the energy, so the switch valve 11 is discharged, and the boom raised by adjusting the displacement of the variable hydraulic pump 3.
[0038] When the boom cylinder needs to be locked, the three four-pass reversing valve 5 is in the median and the switch valve 11 is powered off.
[0039] As can be seen from the above configuration, the present invention is mainly composed of a piston accumulator and a high pressure gas tank, a low pressure gas storage tank. The piston accumulator gas cavity pressure is controlled by high-pressure storage tanks and low pressure gas storage tanks, increasing the range of energy recovery, and can control the lifting of the boom cylinder without passing the throttle control. The throttling loss is reduced, and the system heating is reduced, which reduces the need for heat dissipation. Through real-time monitoring of the above four pressure sensors, it is determined which state is in the above state, and then takes a corresponding control policy. Overall, the above-mentioned energy irreparable and energy unreleaseable will only appear in a small part, so the energy recovery system is working in most cases, and the pressure range of the recyclable pressure is more powerful than traditional. It is high.
[0040] See figure 2 By applying the energy recovery system of the present invention to an existing excavator motor arm, engine output power before and after the energy recovery system of the present invention is applied according to experiments. Obviously, the energy recovery system of the present invention can effectively reduce the energy consumption in the operation of the excavator motor arm.
[0041] It is intended to limit the patent scope of the present invention, and an equivalent structure or equivalent process transform according to the present invention and the equivalent structure or equivalent flow transformation of the present invention and the accompanying drawings, or directly or indirectly. The field, all of which are included within the patent protection range of the present invention.
