Electric reach stacker energy recovery system

Abstract

The utility model discloses an electric reach stacker energy recovery system which comprises a variable amplitude oil cylinder, a large cavity of the variable amplitude oil cylinder is respectively communicated with an A port of a closed variable pump and an oil tank, and a small cavity of the variable amplitude oil cylinder is respectively communicated with a B port of the closed variable pump and an oil supplementing pump. The closed variable pump and the oil supplementing pump are driven by a motor; a port B of the closed variable pump and the oil supplementing pump are also communicated to the oil tank. By combining the four-quadrant characteristic of the motor, the gravitational potential energy of the variable-amplitude oil cylinder is recovered by the swash plate type closed variable pump with positive and negative swing angles; the oil supplementing valve and the oil discharging valve are used for supplementing oil and discharging oil under the condition that the volume of the variable-amplitude oil cylinder is asymmetric; under the working conditions of low load and low speed, oil returns through the electric proportional valve, and the energy consumption of the motor is reduced; the lifting device is suitable for a container reach stacker and machinery with a lifting function in port logistics, such as a container stacker and a heavy forklift.

Description

Technical Field

[0001] The utility model relates to the technical field of energy recovery, and more specifically, it relates to an energy recovery system for an electric reach stacker. Background Art

[0002] The container electric reach stacker, also known as the container reach stacker, is a lifting equipment used for loading and unloading containers. The electric reach stacker is mainly used for stacking and horizontal transportation of containers. Compared with forklifts, the electric reach stacker has the advantages of being flexible, easy to operate, good stability, low wheel pressure, high stacking layers, and high utilization rate. The electric reach stacker can perform cross-container operations, and is especially suitable for container loading and unloading work at small and medium-sized ports, railway transfer stations, and highway transfer stations. It can also be used as an auxiliary equipment at large container terminals.

[0003] In the existing recovery systems, due to the asymmetry of the volumes of the large and small chambers of the hydraulic cylinder, it is necessary to solve the problems of oil replenishment when the cylinder rises and oil drainage when the cylinder descends; the oil in the large chamber of the cylinder is high-pressure oil, and it is necessary to solve the problem of system heat dissipation; the container reach stacker often operates under different loads and speeds, and there is a threshold for the motor to be in the power generation mode, that is, the motor needs to reach a certain speed and negative torque to be converted into a generator. When the motor does not reach the power generation threshold, the motor is still in the motor mode. This requires solving the problem of power consumption of the motor under low-load and micro-slow descent working conditions. Summary of the Utility Model

[0004] Aiming at the deficiencies existing in the prior art, the purpose of the utility model is to provide an energy recovery system for an electric reach stacker to solve one or more of the above problems.

[0005] To achieve the above purpose, the utility model provides the following technical solutions:

[0006] An energy recovery system for an electric reach stacker, comprising

[0007] A luffing cylinder, whose large chamber is respectively connected to the A port of a closed-loop variable pump and the oil tank, and whose small chamber is respectively connected to the B port of the closed-loop variable pump and a makeup oil pump;

[0008] Both the closed-loop variable pump and the makeup oil pump are driven by a motor;

[0009] The B port of the closed-loop variable pump and the makeup oil pump are also connected to the oil tank.

[0010] Further, the closed-loop variable pump is connected to an oil discharge valve and then connected to the oil tank, and a TA radiator is provided at the inlet end of the oil tank.

[0011] Further, a load holding valve is provided between the A port of the closed-loop variable pump and the large chamber of the luffing cylinder, and the load holding valve is also connected to an electro-hydraulic proportional valve and finally connected to the oil tank.

[0012] Further, there is a direct connection between port B of the closed-loop variable pump and the small chamber of the luffing cylinder.

[0013] Further, a filter and a check valve are sequentially connected between the make-up oil pump and the small chamber of the luffing cylinder.

[0014] Further, the filter is also branched after the make-up oil valve and finally connected to the fuel tank, and the make-up oil valve is also connected to a check valve.

[0015] To sum up, the utility model has the following beneficial effects: combining the four-quadrant characteristics of the motor, enabling the swash plate type closed-loop variable pump with positive and negative swing angles to recover the gravitational potential energy of the luffing cylinder; the make-up oil valve and the drain valve are used for make-up oil and drain oil in the case of asymmetric volume of the luffing cylinder; under low-load and micro-slow speed conditions, the oil returns through the electro-hydraulic proportional valve and the motor energy consumption is reduced; it is applicable to reach stackers, and machinery with lifting functions in port logistics, such as container stackers, heavy forklifts, etc. Description of the Drawings

[0016] Figure 1 It is a schematic diagram of the principle structure of an embodiment provided by the utility model.

[0017] In the figure: 1, motor; 2, closed-loop variable pump; 3, make-up oil pump; 4, make-up oil valve; 5, check valve; 6, drain valve; 7, load holding valve; 8, electro-hydraulic proportional valve; 9, filter; 10, luffing cylinder. Detailed Description of the Embodiment

[0018] Embodiment:

[0019] The following further Figure 1 describes the present utility model in detail with reference to the

[0020] An energy recovery system for an electric reach stacker, as Figure 1 shown, is mainly divided into three oil circuits: the oil circuit of the large chamber of the luffing cylinder 10, the oil circuit of the small chamber of the luffing cylinder 10, and the recovery oil circuit. The motor 1 drives the corresponding make-up oil pump 3 and closed-loop variable pump 2.

[0021] The oil circuit of the large chamber of the luffing cylinder 10 includes three branches: the first one is the closed-loop variable pump 2 port A, the load holding valve 7, and the large chamber of the luffing cylinder 10 connected in sequence; the second one is the large chamber of the luffing cylinder 10, the load holding valve 7, the closed-loop variable pump 2, the drain valve 6, and the fuel tank connected in sequence; the third one is the large chamber of the luffing cylinder 10, the load holding valve 7, the electro-hydraulic proportional valve 8, and the fuel tank connected in sequence.

[0022] The oil circuit of the small chamber of the luffing cylinder 10 includes two branches: the first one is the make-up oil pump 3, the filter 9, the check valve 5, the small chamber of the luffing cylinder 10, and the closed-loop variable pump 2 port B connected in sequence; the second one is that the closed-loop variable pump 2 port B is directly connected to the small chamber of the luffing cylinder 10.

[0023] The oil return circuit includes: a make-up oil pump 3, a filter 9, a make-up oil valve 4, and a fuel tank, which are connected in sequence.

[0024] The specific operating principle is as follows: When the electric reach stacker lifts, the motor 1 drives the closed-loop variable pump 2 and the make-up oil pump 3 to rotate. The variable swash plate of the closed-loop variable pump 2 swings forward, and the oil flows out from port A. The oil passes through the load holding valve 7 and enters the large chamber of the boom cylinder 10. At the same time, the make-up oil valve 4 is energized, and the oil from the make-up oil pump 3 is introduced through the filter 9, flows through the check valve 5, and finally enters the small chamber of the boom cylinder 10. The oil in the small chamber of the boom cylinder 10 enters port B of the closed-loop variable pump 2, and the oil realizes a closed-loop circulation through the closed-loop variable pump 2 until the lifting action is completed. During the whole process, the motor 1 does positive work and is in the motor operating mode.

[0025] When the electric reach stacker descends, the motor 1 drives the closed-loop variable pump 2 and the make-up oil pump 3 to rotate. The variable swash plate of the closed-loop variable pump 2 swings backward, and the oil flows out from port B. The oil enters the small chamber of the boom cylinder 10. The make-up oil valve 4 is de-energized, and the oil from the make-up oil pump 3 flows into the fuel tank through the make-up oil valve 4. The load holding valve 7 is energized, and the oil in the large chamber of the boom cylinder 10 enters port A of the closed-loop variable pump 2 through the load holding valve 7. The oil in the large chamber of the boom cylinder 10 is greater than that in the small chamber. The excess oil passes through port B of the closed-loop variable pump 2 and enters the fuel tank through the drain valve 6. The oil realizes a closed-loop circulation through the closed-loop variable pump 2 until the descending action is completed. During the descending process, since the oil in the large chamber of the boom cylinder 10 is high-pressure oil, the pressure at port A is greater than that at port B. The oil does negative work on the motor 1 through port A of the closed-loop variable pump 2. The motor 1 has a four-quadrant function, and the negative torque generated at this time drives the motor 1 to be in the power generation operating mode, achieving the purpose of converting gravitational potential energy into electrical energy and recovering energy.

[0026] In addition, when the equipment is in a low-load or very slow descending operating condition, the negative work generated by the closed-loop variable pump 2 is insufficient to drive the motor 1 to convert to power generation. At this time, the load holding valve 7 and the electro-hydraulic proportional valve 8 are energized, and the oil in the large chamber of the boom cylinder 10 enters the oil return system through the load holding valve 7 and the electro-hydraulic proportional valve 8. By changing the current magnitude of the electro-hydraulic proportional valve 8, the descending speed of the boom cylinder 10 is changed. At this time, the swash plate of the closed-loop variable pump 2 is in the middle position, and the motor 1 does not do work, reducing the energy consumption of the motor 1 under low-load and very slow operating conditions.

[0027] A TA radiator is installed during the oil return process. When the equipment is in the descending operating condition, the hot oil in the boom cylinder 10 is cooled and dissipated heat through the TA radiator under the action of the drain valve 6 or the electro-hydraulic proportional valve 8 and then enters the fuel tank, where it exchanges heat with the cold oil in the tank. When the equipment is in the lifting operating condition, the cold oil in the hydraulic fuel tank enters the oil circuit under the action of the make-up oil pump 3, realizing the heat exchange cycle of the hydraulic oil.

[0028] The device can recover gravitational potential energy without adding motors and generators in the hydraulic system, can fill and drain oil in the case of asymmetric cylinder system volume, reduces the energy consumption of the device, and is beneficial to extending the operation time.

[0029] It should be noted that this specific embodiment is only an interpretation of the present invention, and it does not limit the present invention. After reading this specification, those skilled in the art can make modifications to this embodiment without creative contributions as needed, but as long as it is within the scope of the claims of the present invention, it is protected by the patent law.

Claims

1. Electric reachstacker energy recovery system, characterized in that: including a luffing oil cylinder (10), the large chambers of which are respectively connected to the A port of a closed-loop variable pump (2) and an oil tank, and the small chambers are respectively connected to the B port of the closed-loop variable pump (2) and a makeup oil pump (3); both the closed-loop variable pump (2) and the makeup oil pump (3) are driven by a motor (1); the B port of the closed-loop variable pump (2) and the makeup oil pump (3) are also connected to the oil tank.

2. The energy recovery system of the electric reach stacker according to claim 1, wherein: The closed-loop variable pump (2) is connected to an oil discharge valve (6) and then connected to the oil tank, and a TA radiator is provided at the inlet end of the oil tank.

3. The energy recovery system of the electric reach stacker according to claim 2, characterized in that: A load holding valve (7) is provided between the A port of the closed-loop variable pump (2) and the large chamber of the luffing oil cylinder (10), and the load holding valve (7) is also connected to an electro-hydraulic proportional valve (8) and finally connected to the oil tank.

4. The energy recovery system of the electric reachstacker according to claim 2, characterized in that: There is a direct connection between the B port of the closed-loop variable pump (2) and the small chamber of the luffing oil cylinder (10).

5. The energy recovery system of the electric reachstacker according to claim 4, wherein: A filter (9) and a check valve (5) are sequentially connected between the makeup oil pump (3) and the small chamber of the luffing oil cylinder (10).

6. The energy recovery system of the electric reach stacker according to claim 5, wherein: The filter (9) is also branched to a makeup oil valve (4) and finally connected to the oil tank, and the makeup oil valve (4) is also connected to the check valve (5).

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