An energy recovery type digital hydraulic pump

Abstract

The present invention discloses an energy recovery type digital hydraulic pump, belonging to the technical field of hydraulic equipment. The energy recovery type digital hydraulic pump includes: a piston pump, which includes a plurality of piston cylinders; a plurality of control circuits, each control circuit includes a first stop valve, a second stop valve and a check valve, the input end of the check valve, the first stop valve and the second stop valve are all communicated with the cylinder block of a piston cylinder; a pressure oil circuit, provided with a pressure oil port, and the pressure oil port can be communicated with the lifting cylinder of an actuator; a suction oil circuit, provided with a suction oil port, and the suction oil port is communicated with the fuel tank; an energy recovery circuit, provided with an energy recovery port, and the energy recovery port can be communicated with the lifting cylinder of another actuator. The energy recovery type digital hydraulic pump of the present invention has multiple working modes, can not only achieve pure external work, but also recover the high-pressure hydraulic oil in the actuator, so as to realize the recovery and utilization of energy and improve the energy efficiency of the entire hydraulic system.

Description

Technical Field

[0001] The present invention relates to the technical field of hydraulic equipment, and particularly to an energy recovery type digital hydraulic pump. Background Art

[0002] Hydraulic systems often use hydraulic pumps as power components. They mainly use engines or electric motors to drive the internal components of the pump to move, thereby causing changes in the pump chamber volume. When the pump chamber volume increases, oil is sucked from the hydraulic oil tank, and when the pump chamber volume decreases, pressurized oil is discharged, thereby compressing the fluid to make the fluid have pressure energy and sending the fluid with pressure energy to the actuator to perform work tasks. Hydraulic pumps are classified into gear pumps, piston pumps, vane pumps, and screw pumps according to their structures.

[0003] Hydraulic pumps using electro-hydraulic servo or electro-hydraulic proportional control are of great significance for realizing the automation and energy saving of hydraulic system control. Digital controlled hydraulic pumps are controlled by a computer and consist of two parts: a main body and a variable mechanism. The variable mechanism is controlled and adjusted by an electro-hydraulic digital control valve.

[0004] In the existing digital hydraulic pump, its control valve group cannot determine when the hydraulic oil returns through the oil suction port or the energy recovery port and determine the duration of the hydraulic oil return process, making it difficult to achieve the switching of the working mode of each plunger of the digital pump, the timed opening and closing of the solenoid valves in the control valve group, and the hydraulic oil pressure transformation operation of the valve port group. Therefore, it lacks the function of directly recovering hydraulic energy, resulting in low energy efficiency of the hydraulic system. Therefore, it is not suitable for application scenarios with negative loads that often occur in actual working processes such as construction machinery. Summary of the Invention

[0005] The purpose of the present invention is to overcome the problems in the prior art and provide an energy recovery type digital hydraulic pump with multiple working modes, which can not only perform simple external work, but also recover the high-pressure hydraulic oil in the actuator, thereby realizing the recovery and utilization of energy and improving the energy efficiency of the entire hydraulic system.

[0006] The present invention provides an energy recovery type digital hydraulic pump, including:

[0007] A piston pump, including a plurality of piston cylinders;

[0008] A plurality of control circuits, each control circuit is connected to the cylinder block of a different piston cylinder. Each control circuit includes a first stop valve, a second stop valve, and a check valve. The input end of the check valve, the first stop valve, and the second stop valve are all connected to the cylinder block of a piston cylinder;

[0009] A pressure oil circuit, connected to the output ends of the check valves of different control circuits. The pressure oil circuit is provided with a pressure oil port, and the pressure oil port can be connected to the lifting cylinder of an actuator;

[0010] An oil suction circuit is communicated with the first shut-off valve of different control circuits. The oil suction circuit is provided with an oil suction port which is communicated with an oil tank.

[0011] An energy recovery circuit is communicated with the second shut-off valve of different control circuits. The energy recovery circuit is provided with an energy recovery port which can be communicated with a lifting cylinder of another actuator.

[0012] Preferably, the piston pump further includes a power device and an eccentric wheel. The output end of the power device is connected to the eccentric wheel. The outer side wall of the eccentric wheel abuts against the pistons of different piston cylinders. Springs are arranged on the pistons of the piston cylinders, and the springs are used to apply elastic forces to the pistons.

[0013] Preferably, it further includes a controller. The first shut-off valve and the second shut-off valve of each control circuit are both electromagnetic shut-off valves. The controller is electrically connected to the first shut-off valve and the second shut-off valve of each control circuit.

[0014] Preferably, the controller is further electrically connected to a signal generator. The signal generator is electrically connected to the first shut-off valve and the second shut-off valve of each control circuit. The signal generator is used to apply a pulse control signal to the first shut-off valve or the second shut-off valve of the same control circuit, and the pulse control signal is used to control the opening and closing of the first shut-off valve or the second shut-off valve.

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows: An energy recovery type digital hydraulic pump of the present invention has multiple working modes. It can not only achieve pure external work, but also recover the high-pressure hydraulic oil in the actuator, thereby realizing the recovery and utilization of energy and improving the energy efficiency of the entire hydraulic system.

[0016] By driving the eccentric wheel to rotate through the power device, the entire hydraulic pump has a high transmission power and improves the reliability of the entire hydraulic pump. Setting the first shut-off valve and the second shut-off valve as electromagnetic shut-off valves and controlling the actions of the first shut-off valve and the second shut-off valve through the controller can improve the automation degree of the entire hydraulic pump. By setting the signal generator, the automation degree of this hydraulic pump can be further improved, and precise control of the first solenoid valve and the second solenoid valve can be realized. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic structural principle diagram of the present invention under the first working mode;

[0018] Figure 2 It is a schematic working condition diagram of the present invention under the first working mode;

[0019] Figure 3 It is a schematic structural principle diagram of the present invention under the second working mode;

[0020] Figure 4 It is a schematic diagram of the working condition in the second working mode of the present invention;

[0021] Figure 5 It is a schematic diagram of the structural principle in the third working mode of the present invention;

[0022] Figure 6 It is a schematic diagram of the working condition in the third working mode of the present invention.

[0023] Explanation of reference numerals:

[0024] 101. Plunger pump, 102. Cylinder block, 103. First check valve, 104. Second check valve, 105. One-way valve, 106. Pressure oil circuit, 107. Lifting cylinder, 108. Pressure oil port, 109. Oil suction circuit, 110. Oil suction port, 111. Oil tank, 112. Energy recovery circuit, 113. Energy recovery port, 201. Power device, 202. Eccentric wheel, 203. Piston, 204. Spring, 3. Controller, 4. Load. Specific embodiments

[0025] The following combines the attached Figures 1-6 , and describes the specific embodiments of the present invention in detail, but it should be understood that the protection scope of the present invention is not limited by the specific embodiments. Based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0026] Embodiment 1:

[0027] As Figures 1-6As shown in the figure, an energy recovery type digital hydraulic pump provided by the present invention includes: a plunger pump 101, a plurality of control circuits, a pressure oil circuit 106, a suction oil circuit 109, and an energy recovery circuit 112. The plunger pump 101 includes a plurality of plunger cylinders; each of the plurality of control circuits is connected to the cylinder block 102 of a different plunger cylinder. Each control circuit includes a first stop valve 103, a second stop valve 104, and a check valve 105. The input end of the check valve 105, the first stop valve 103, and the second stop valve 104 are all connected to the cylinder block 102 of a plunger cylinder; the pressure oil circuit 106 is connected to the output ends of the check valves 105 of different control circuits. The pressure oil circuit 106 is provided with a pressure oil port 108, and the pressure oil port 108 can be connected to the lifting cylinder 107 of an actuator; the suction oil circuit 109 is connected to the first stop valves 103 of different control circuits. The suction oil circuit 109 is provided with a suction oil port 110, and the suction oil port 110 is connected to the fuel tank 111; the energy recovery circuit 112 is connected to the second stop valves 104 of different control circuits. The energy recovery circuit 112 is provided with an energy recovery port 113, and the energy recovery port 113 can be connected to the lifting cylinder 107 of another actuator.

[0028] Now briefly describe the working principle of Embodiment 1:

[0029] This device has three working modes during use:

[0030] External work mode: Open the first stop valves 103 of all control circuits and close the second stop valves 104 of all control circuits. At this time, start the plunger pump 101, the plunger pump 101 operates, the plunger cylinders reciprocate, so as to continuously absorb hydraulic oil from the fuel tank 111 through the first stop valves 103, and squeeze the hydraulic oil in the cylinder block 102 of the plunger cylinder into the lifting cylinder 107 of the actuator connected to the pressure oil port 108 through the check valve 105, so as to lift the load 4 on the actuator through the lifting component, realizing pure external work.

[0031] External work done + energy recovery mode: Intermittently open or close the first cut-off valve 103 of all control circuits or close the second cut-off valve 104 of all control circuits. At this time, start the plunger pump 101, and the plunger pump 101 operates, and the plunger cylinder reciprocates. When the cylinder block 102 of the plunger cylinder is in the oil inlet process, the first cut-off valve 103 and the second cut-off valve 104 of all control circuits are opened in sequence. When the first cut-off valve 103 is opened and the second cut-off valve 104 is closed, the cylinder block 102 of the plunger cylinder sucks oil from the fuel tank 111 through the first cut-off valve 103; when the first cut-off valve 103 is closed and the second cut-off valve 104 is opened, the high-pressure hydraulic oil in the lifting cylinder 107 of the actuator connected to the energy recovery port 113 enters the cylinder block 102 of the plunger cylinder through the second cut-off valve 104. When the cylinder block 102 of the plunger cylinder is in the oil pressure process, close the first cut-off valve 103 and the second cut-off valve 104 of all control circuits. At this time, all the hydraulic oil in the cylinder block 102 of the plunger cylinder enters the lifting cylinder 107 of another actuator connected to the oil pressure port 108 through the one-way valve 105, thereby lifting the load 4 on this actuator. Thus, the energy of the high-pressure hydraulic oil is recovered from the lifting cylinder 107 of one actuator and oil is replenished from the fuel tank 111, driving the lifting cylinder 107 of another actuator to move, thereby realizing the recovery and utilization of energy.

[0032] Energy recovery mode: Intermittently open the first cut-off valve 103 and the second cut-off valve 104 separately. When the cylinder block 102 of the plunger cylinder is in the oil inlet process, the second cut-off valve 104 of all control circuits is intermittently opened. When the second cut-off valve 104 is opened, the high-pressure hydraulic oil in the lifting cylinder 107 of the actuator connected to the energy recovery port 113 enters the cylinder block 102 of the plunger cylinder through the second cut-off valve 104. When the cylinder block 102 of the plunger cylinder is in the oil pressure process, close the second cut-off valve 104 of all control circuits and open the first cut-off valve 103 of all control circuits. At this time, the hydraulic oil in the cylinder block 102 of the plunger cylinder enters the fuel tank 111 connected to the oil suction port 110 through the first cut-off valve 103, thereby realizing the recovery of the energy of the high-pressure hydraulic oil from the lifting cylinder 107 of the actuator, entering the fuel tank to replenish oil for the hydraulic system, and thus realizing the recovery and utilization of energy.

[0033] An energy recovery type digital hydraulic pump of the present invention has multiple working modes, can not only achieve pure external work done, but also recover the high-pressure hydraulic oil in the actuator, thereby realizing the recovery and utilization of energy and improving the energy efficiency of the entire hydraulic system.

[0034] Embodiment 2:

[0035] On the basis of Embodiment 1, in order to make the entire hydraulic pump have a high transmission power and improve the reliability of the entire hydraulic pump.

[0036] AsFigure 1 , 3 As shown in FIGS. 4, 3 and 5, the plunger pump 101 further includes a power device 201 and an eccentric wheel 202. The output end of the power device 201 is connected to the eccentric wheel 202. The outer side wall of the eccentric wheel 202 abuts against the pistons 203 of different plunger cylinders. A spring 204 is provided on the piston 203 of the plunger cylinder, and the spring 204 is used to apply an elastic force to the piston 203.

[0037] By driving the eccentric wheel 202 to rotate through the power device 201, the driving force applied by the rotating eccentric wheel 202 combined with the elastic force of the spring 204 enables the piston 203 of the plunger cylinder to reciprocate within the cylinder block 102 of the plunger cylinder, thereby realizing the oil suction and oil discharge functions of the plunger pump 101, having a relatively high transmission power, and improving the reliability of the entire hydraulic pump.

[0038] As a preferred solution, as Figure 1 , 3 shown in FIGS. 4, 3 and 5, it further includes a controller 3. The first stop valve 103 and the second stop valve 104 of each control loop are both electromagnetic stop valves, and the controller 3 is electrically connected to the first stop valve 103 and the second stop valve 104 of each control loop. By setting the first stop valve 103 and the second stop valve 104 as electromagnetic stop valves and controlling the actions of the first stop valve 103 and the second stop valve 104 through the controller 3, the automation degree of the entire hydraulic pump can be improved.

[0039] As a preferred solution, as Figure 1 , 3 shown in FIGS. 4, 3 and 5, the controller 3 is further electrically connected to a signal generator. The signal generator is electrically connected to the first stop valve 103 and the second stop valve 104 of each control loop. The signal generator is used to apply a pulse control signal to the first stop valve 103 or the second stop valve 104 of the same control loop, and the pulse control signal is used to control the opening and closing of the first stop valve 103 or the second stop valve 104. By setting the signal generator, encoding the action sequence of the switches of the first solenoid valve and the second solenoid valve in three working modes in the signal generator, and controlling the action of the first solenoid valve or the second solenoid valve through this encoding, the automation degree of this hydraulic pump can be further improved, and precise control of the first solenoid valve and the second solenoid valve can be realized.

[0040] Although the embodiments of the present invention have been shown and described, for those of ordinary skill in the art, it can be understood that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. An energy recovery type digital hydraulic pump, characterized in that, it includes: a piston pump (101) including a plurality of piston cylinders; a plurality of control circuits, each control circuit is communicated with the cylinder block (102) of a different piston cylinder, and each control circuit includes a first stop valve (103), a second stop valve (104) and a check valve (105). The input end of the check valve (105), the first stop valve (103) and the second stop valve (104) are all communicated with the cylinder block (102) of a piston cylinder; a pressure oil circuit (106) communicated with the output ends of the check valves (105) of different control circuits. The pressure oil circuit (106) is provided with a pressure oil port (108), and the pressure oil port (108) can be communicated with the lifting cylinder (107) of an actuator; a suction oil circuit (109) communicated with the first stop valves (103) of different control circuits. The suction oil circuit (109) is provided with a suction oil port (110), and the suction oil port (110) is communicated with an oil tank (111); an energy recovery circuit (112) communicated with the second stop valves (104) of different control circuits. The energy recovery circuit (112) is provided with an energy recovery port (113), and the energy recovery port (113) can be communicated with the lifting cylinder (107) of another actuator; a controller (3) electrically connected to a signal generator, and the signal generator is electrically connected to the first stop valve (103) and the second stop valve (104) of each control circuit. The signal generator is used to apply a pulse control signal to the first stop valve (103) or the second stop valve (104) of the same control circuit, and the pulse control signal is used to control the opening and closing of the first stop valve (103) or the second stop valve (104); When doing external work: open the first stop valves (103) of all control circuits and close the second stop valves (104) of all control circuits, start the piston pump (101), absorb hydraulic oil from the oil tank (111) through the first stop valve (103), and squeeze the hydraulic oil in the cylinder block (102) of the piston cylinder into the lifting cylinder (107) of the actuator communicated with the pressure oil port (108) through the check valve (105), and lift the load (4) on the actuator through the lifting component to achieve pure external work; During external work and energy recovery: Start the plunger pump (101), and the plunger cylinder reciprocates. When the cylinder block (102) of the plunger cylinder is in the oil intake process, the first shut-off valve (103) and the second shut-off valve (104) of all control circuits are opened in sequence. When the first shut-off valve (103) is opened and the second shut-off valve (104) is closed, the cylinder block (102) of the plunger cylinder sucks oil from the fuel tank (111); when the first shut-off valve (103) is closed and the second shut-off valve (104) is opened, the high-pressure hydraulic oil in the lifting cylinder (107) of the actuator enters the cylinder block (102) of the plunger cylinder. When the cylinder block (102) of the plunger cylinder is in the oil pressure process, the first shut-off valve (103) and the second shut-off valve (104) of all control circuits are closed, and all the hydraulic oil in the cylinder block (102) of the plunger cylinder enters the lifting cylinder (107) of another actuator connected to the oil pressure port (108) through the one-way valve (105) to lift the load (4) on the actuator. During energy recovery: When the cylinder block (102) of the plunger cylinder is in the oil intake process, the second shut-off valve (104) of all control circuits is intermittently opened. When the second shut-off valve (104) is opened, the high-pressure hydraulic oil in the lifting cylinder (107) of the actuator connected to the energy recovery port (113) enters the cylinder block (102) of the plunger cylinder. When the cylinder block (102) of the plunger cylinder is in the oil pressure process, the second shut-off valve (104) of all control circuits is closed, and the first shut-off valve (103) of all control circuits is opened. The hydraulic oil in the cylinder block (102) of the plunger cylinder enters the fuel tank (111) connected to the oil suction port (110), thereby realizing the energy recovery of the high-pressure hydraulic oil from the lifting cylinder (107) of the actuator and entering the fuel tank (111) to replenish oil for the hydraulic system for energy recovery and utilization.

2. An energy recovery type digital hydraulic pump according to claim 1, characterized in that, the plunger pump (101) further includes a power device (201) and an eccentric wheel (202), the output end of the power device (201) is connected to the eccentric wheel (202), the outer side wall of the eccentric wheel (202) abuts against the pistons (203) of different plunger cylinders, and a spring (204) is provided on the piston (203) of the plunger cylinder, and the spring (204) is used to apply an elastic force to the piston (203).

3. An energy recovery type digital hydraulic pump according to claim 2, characterized in that, the first shut-off valve (103) and the second shut-off valve (104) of each control circuit are both electromagnetic shut-off valves, and the controller (3) is electrically connected to the first shut-off valve (103) and the second shut-off valve (104) of each control circuit.

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