Novel electric reach stacker energy recovery system

Abstract

The utility model discloses a novel 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 oil tank and a variable pump, and a small cavity of the variable amplitude oil cylinder is respectively communicated with the large cavity and the oil tank. The variable pump is driven by a motor; the variable pump is also communicated with 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 open variable pump with positive and negative swing angles; when an oil suction port of the variable pump is converted into an oil outlet for use in a one-way valve combination mode, the heat dissipation capacity of the system is improved; 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 a new energy recovery system for an electric reach stacker. Background Art

[0002] An electric reach stacker, also known as a container reach stacker, is a lifting device used for loading and unloading containers. The electric reach stacker is mainly used for stacking and horizontal transportation of containers. Compared with a forklift, 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 device at large container terminals.

[0003] At present, the existing recovery systems are applied to oil cylinder systems with asymmetric volumes, and have complex structures and relatively high costs; there is a threshold for the motor in the power generation working condition, that is, the motor needs to reach a certain speed and negative torque to convert into the working mode of a generator. When the motor does not reach the power generation threshold, the motor still remains in the working mode of the motor. When the whole system is in low-load and micro-slow descent working conditions, the power consumption problem is serious. Summary of the Utility Model

[0004] Aiming at the deficiencies of the existing technology, the purpose of the utility model is to provide a new 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] A new energy recovery system for an electric reach stacker, comprising

[0007] A luffing oil cylinder, whose large chambers are respectively connected to an oil tank and a variable pump, and whose small chambers are respectively connected to the large chambers and the oil tank;

[0008] The variable pump is driven by a motor;

[0009] The variable pump is also connected to the oil tank.

[0010] Further, the oil suction port of the variable pump is connected to the oil tank through an oil suction check valve, and the oil outlet of the variable pump is sequentially connected to a load holding valve and the large chamber of the luffing oil cylinder.

[0011] Further, an electro-hydraulic proportional valve is connected in parallel between the oil outlet and the oil suction port of the variable pump, and a first check valve is provided between the electro-hydraulic proportional valve and the oil suction port of the variable pump.

[0012] Further, the small chamber of the luffing oil cylinder is connected to the oil tank through a second check valve, and a hydraulic oil radiator is connected in parallel between the first check valve and the second check valve.

[0013] Further, the flow directions of both the second check valve and the first check valve are set to point towards the fuel tank, while the flow direction of the oil suction check valve is set to point towards the variable pump.

[0014] Further, the variable pump is an open-type positive and negative swash plate variable pump.

[0015] In summary, the present utility model has the following beneficial effects: By combining the four-quadrant characteristics of the motor, the open-type variable pump with a swash plate having positive and negative swash angles recovers the gravitational potential energy of the luffing cylinder; When the oil suction port of the variable pump is converted to the oil outlet, the heat dissipation capacity of the system is improved by using a combination of check valves; Under low-load and micro-slow-speed working conditions, the oil returns through the electro-hydraulic proportional valve and the motor energy consumption is reduced; It is applicable to container reach stackers, machinery with lifting functions in port logistics, such as container stackers, heavy forklifts, etc. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0017] In the figure: 1, motor; 2, variable pump; 3, hydraulic oil radiator; 4, oil suction check valve; 5, electro-hydraulic proportional valve; 6, load holding valve; 7, luffing cylinder; 8, second check valve; 9, first check valve. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0018] Embodiment:

[0019] The following further Figure 1 describes the present utility model in detail.

[0020] A new type of electric reach stacker energy recovery system, as Figure 1 shown, includes three oil circuits: The first oil circuit includes a fuel tank, an oil suction check valve 4, the oil suction port of the variable pump 2, the oil outlet of the variable pump 2, a load holding valve 6, and the large chamber of the luffing cylinder 7 connected in sequence; The second oil circuit includes the large chamber of the luffing cylinder 7, a load holding valve 6, the oil outlet of the variable pump 2, the oil suction port of the variable pump 2, a first check valve 9, a hydraulic oil radiator 3, and the small chamber of the luffing cylinder 7 connected in sequence; The third includes the large chamber of the luffing cylinder 7, a load holding valve 6, an electro-hydraulic proportional valve 5, a second check valve 8, and a fuel tank connected in sequence. The variable pump 2 can be directly connected to the fuel tank.

[0021] The overall structure includes a variable pump 2 driven by a motor 1 to rotate, a hydraulic oil radiator 3, a suction check valve 4, an electro-hydraulic proportional valve 5, a load holding valve 6, a luffing cylinder 7, a second check valve 8, and a first check valve 9. The variable pump 2 is an open-type positive and negative swash plate variable pump 2. The variable pump 2 is directly connected to the fuel tank. The suction port of the variable pump 2 is connected to the fuel tank through the suction check valve 4, and the flow direction of the suction check valve 4 is set to point to the variable pump 2. The outlet port of the variable pump 2 is connected to the large chamber of the luffing cylinder 7 through the load holding valve 6. The outlet port and the suction port of the variable pump 2 are respectively connected in parallel with the electro-hydraulic proportional valve 5. A first check valve 9 is provided between the electro-hydraulic proportional valve 5 and the suction port of the variable pump 2, and the flow direction of the first check valve 9 is set to point to the fuel tank. The small chamber of the luffing cylinder 7 is connected to the fuel tank through the second check valve 8, and the flow direction of the second check valve 8 is set to point to the fuel tank. The hydraulic oil radiator 3 is connected in parallel between the second check valve 8 and the first check valve 9.

[0022] When the reachstacker is in the lifting state, the motor 1 rotates to drive the variable pump 2 to operate. The swash plate of the variable pump 2 has a positive swing angle. The oil in the fuel tank flows through the suction check valve 4 to the suction port of the variable pump 2, passes through the variable pump 2, and enters the large chamber of the luffing cylinder 7 from the outlet port of the variable pump 2 through the load holding valve 6. The speed of the lifting action is adjusted by changing the swash plate angle throughout the process until the lifting target is completed. At this time, the motor 1 does positive work and is in the motor working condition.

[0023] When the reachstacker is in the lowering state, the motor 1 rotates to drive the variable pump 2 to operate. The swash plate of the variable pump 2 has a negative swing angle and discharges oil from the suction port. The electromagnet of the load holding valve 6 is energized. The oil discharged from the large chamber of the luffing cylinder 7 enters the outlet port of the variable pump 2 through the load holding valve 6, passes through the suction port of the variable pump 2, and flows through the first check valve 9 into the hydraulic oil radiator 3. The outlet port of the hydraulic oil radiator 3 is connected to the small chamber of the luffing cylinder 7 to replenish oil for it. The excess oil returns to the fuel tank through the second check valve 8 to complete the lowering action. In this process, the oil in the large chamber of the luffing cylinder 7 is high-pressure oil, that is, the pressure at the outlet port of the variable pump 2 is greater than the pressure at the suction port. The oil does negative work on the motor 1 through the outlet port of the variable pump 2. The motor 1 has a four-quadrant function. The negative torque generated by the variable pump 2 makes the motor 1 in the generating working condition, realizing the energy recovery of converting the gravitational potential energy of the luffing cylinder 7 into electrical energy. The motor 1 is in the generator 1 working condition.

[0024] When the reachstacker is in the low-load and very slow lowering working condition, the negative work generated by the variable pump 2 is not enough to reach the threshold for the motor 1 to be in the generating working condition. The load holding valve 6 and the electro-hydraulic proportional valve 5 are energized. The oil in the large chamber of the luffing cylinder 7 enters the fuel tank through the two valves. By changing the current magnitude of the electro-hydraulic proportional valve 5, the lowering speed of the luffing cylinder 7 is changed. At this time, the swash plate of the variable pump 2 is at the middle swing angle position, and the motor 1 does not do work, realizing that the motor 1 does not consume electrical energy under the low-load and very slow working conditions.

[0025] An oil suction check valve 4 and a first check valve 9 are installed on the variable pump 2, so that when in the lowering condition, the hot oil in the luffing cylinder 7 is cooled by the hydraulic oil radiator 3 through the first check valve 9 or the electro-hydraulic proportional valve 5 and then supplies oil to the luffing cylinder 7 or enters the fuel tank and exchanges heat with the cold oil in the fuel tank. When in the lifting condition, the cold oil in the fuel tank enters the system through the oil suction check valve 4 to realize the circulating heat dissipation of the system hydraulic oil. This not only solves the problem of energy recovery of the electric reach stacker without adding a motor and a generator 1, but also effectively improves the heat dissipation performance during the oil port conversion under various complex working conditions of the electric reach stacker.

[0026] It should be noted that this specific embodiment is only an interpretation of the present invention and not a limitation thereof. After reading this specification, those skilled in the art can make modifications to this embodiment without creative contributions according to needs, but as long as they are within the scope of the claims of the present invention, they are protected by the patent law.

Claims

1. New electric reach stacker energy recovery system, characterized in that: including a boom cylinder (7), the large chambers of which are respectively connected to an oil tank and a variable pump (2), and the small chambers are respectively connected to the large chambers and the oil tank; the variable pump (2) is driven by a motor (1); the variable pump (2) is also connected to the oil tank.

2. The novel energy recovery system for reachstacker according to claim 1, wherein: the oil suction port of the variable pump (2) is connected to the oil tank through an oil suction check valve (4), and the oil outlet of the variable pump (2) is sequentially connected to a load holding valve (6) and the large chamber of the boom cylinder (7).

3. The novel electric reachstacker energy recovery system according to claim 2, characterized in that: an electro-hydraulic proportional valve (5) is connected in parallel between the oil outlet and the oil suction port of the variable pump (2), and a first check valve (9) is provided between the electro-hydraulic proportional valve (5) and the oil suction port of the variable pump (2).

4. The novel energy recovery system for a reachstacker according to claim 3, characterized in that: the small chamber of the boom cylinder (7) is connected to the oil tank through a second check valve (8), and a hydraulic oil radiator (3) is connected in parallel between the first check valve (9) and the second check valve (8).

5. The novel energy recovery system for reachstacker according to claim 4, wherein: the flow directions of the second check valve (8) and the first check valve (9) are both set to point to the oil tank, and the flow direction of the oil suction check valve (4) is set to point to the variable pump (2).

6. The novel energy recovery system for reachstacker according to claim 1, wherein: the variable pump (2) is an open-type positive and negative swing angle swash plate variable pump.

Images