A forklift potential energy recovery and reuse system

Abstract

The present invention provides a forklift potential energy recovery and reuse system, comprising a hydraulic drive module, a hydraulic control module and an energy recovery module; the hydraulic drive module comprises a lifting cylinder group and a three-position six-way electromagnetic reversing valve, and the hydraulic power unit is connected to the lifting cylinder group through the three-position six-way electromagnetic reversing valve; the energy recovery module comprises a recovery cylinder group and a two-position two-way electromagnetic reversing valve; the rodless chamber inlet of the recovery cylinder group is connected to the rodless chamber inlet of the lifting cylinder through the two-position two-way electromagnetic reversing valve; the rod chamber of the recovery cylinder group is connected to the rod chamber of the lifting cylinder through the two-position two-way electromagnetic valve; the rod chamber inlet of the recovery cylinder group is connected to the hydraulic power unit through the two-position two-way electromagnetic reversing valve; the hydraulic control module is used to recover energy during the load lowering process by selectively controlling the combination between the three-position six-way electromagnetic reversing valve and the two-position two-way electromagnetic reversing valve. The present invention can effectively improve the energy utilization rate of the forklift and the life of the hydraulic system components.

Description

Technical Field

[0001] The invention relates to the field of forklifts or the field of energy conversion of lifting equipment, and in particular to a forklift potential energy recovery and reuse system. Background Art

[0002] With the rapid development of social economy, modern industrial logistics system has become the infrastructure to promote social development and economic construction, and it is of great significance to the formation of national economic scale and the development of modern industry. The types, frequency and scale of logistics in modern industrial logistics system are increasing rapidly. Therefore, the importance of loading and unloading is more significant. Forklifts are widely used in various places in the industrial transportation industry with their efficient handling capacity and strong operation flexibility. On the other hand, the energy crisis and environmental protection issues are severe. The demand for energy conservation and environmental protection has greatly promoted the transformation and upgrading of forklifts, and also put forward higher standards and requirements for the energy consumption of forklift hydraulic systems.

[0003] Traditional forklift hydraulic systems use a relief valve to directly release pressurized oil to the oil tank to achieve load reduction. This method causes huge energy losses and low energy efficiency for forklifts with heavy loads and frequent lifting. Therefore, it is necessary to design a new energy-saving forklift lifting system to reasonably recycle and reuse its lifting potential energy to achieve energy-saving transformation of forklifts.

[0004] The existing forklift energy recovery system usually uses hydraulic accumulators and converts the potential energy of the load into electrical energy to save energy, but the technology is not yet mature, the energy recovery efficiency is difficult to guarantee, and it is difficult to control. The accumulator equipment is bulky, which affects the internal space layout of the forklift and the operational maneuverability of the entire vehicle. The electrical recovery method has high requirements for hydraulic motors and generators, and the energy undergoes multiple conversions, so the skill efficiency is low and it is not suitable for promotion to traditional internal combustion engine forklifts. Summary of the invention

[0005] In view of the deficiencies in the prior art, the present invention provides a forklift potential energy recovery and reuse system, which can effectively improve the energy utilization rate of the forklift and the life of the hydraulic system components, and reduce the use cost of the forklift.

[0006] The present invention achieves the above technical objectives through the following technical means.

[0007] A forklift potential energy recovery and reuse system, comprising a hydraulic drive module, a hydraulic control module, and a potential energy recovery and reuse module;

[0008] The hydraulic drive module includes a lifting cylinder group, a hydraulic power unit and a three-position six-way electromagnetic reversing valve. The lifting cylinder group is used to lift the load. The hydraulic power unit is connected to the lifting cylinder group through the three-position six-way electromagnetic reversing valve to lift the lifting cylinder group.

[0009] The potential energy recovery and reuse module includes a recovery cylinder group, a three-position six-way solenoid reversing valve, a first two-position two-way solenoid valve, a second two-position two-way solenoid valve, a third two-position two-way solenoid valve and a fourth two-position two-way solenoid valve; the recovery cylinder group is used to push the slider; the rodless chamber of the recovery cylinder group is connected with the rodless chamber of the lifting cylinder group through the fourth two-position two-way solenoid valve; the rod chamber of the recovery cylinder group is connected with the rod chamber of the lifting cylinder group and the hydraulic oil tank through the second two-position two-way solenoid valve; the rod chamber of the recovery cylinder group is connected with the three-position six-way solenoid reversing valve through the first two-position two-way solenoid valve; a third two-position two-way solenoid valve is provided between the second two-position two-way solenoid valve and the hydraulic oil tank;

[0010] The control module selectively controls the three-position six-way solenoid reversing valve, the first two-position two-way solenoid valve, the second two-position two-way solenoid valve, the third two-position two-way solenoid valve, and the fourth two-position two-way solenoid valve to connect the rodless chamber outlet of the lifting cylinder group with the rodless chamber inlet of the recovery cylinder group, and connect the rod chamber outlet of the lifting cylinder group with the rod chamber inlet of the recovery cylinder group, so as to recover energy during the load lowering process and release the stored energy when the load rises.

[0011] Furthermore, the hydraulic power unit includes an engine, a variable displacement pump, a hydraulic oil tank and a relief valve, the engine is used to drive the variable displacement pump, the oil inlet of the variable displacement pump is connected to the hydraulic oil tank, and the oil outlet of the variable displacement pump is installed with a relief valve.

[0012] Furthermore, the interfaces of the three-position six-way solenoid reversing valve include port P, port T, port D, port A, port B, and port C. The port P and port D are respectively connected to the hydraulic power unit, the port A and port T are connected to the hydraulic oil tank, the port B is connected to the fourth two-position two-way solenoid reversing valve and the rodless chamber of the lifting cylinder group, and the port C is connected to the first two-position two-way solenoid valve.

[0013] Furthermore, the sliding block is a forklift balance block.

[0014] Further, the hydraulic control module includes a first pressure sensor, a second pressure sensor and a control console; the first pressure sensor is used to detect the working pressure of the rodless chamber of the lifting cylinder group, and the second pressure sensor is used to detect the working pressure of the rodless chamber of the recovery cylinder group; the control console selectively controls the three-position six-way solenoid reversing valve and the fourth two-position two-way solenoid reversing valve according to the detection values ​​of the first pressure sensor and the second pressure sensor, so that the rodless chamber of the lifting cylinder group is connected with the rodless chamber of the recovery cylinder group; the control console selectively controls the second two-position two-way solenoid reversing valve according to the detection values ​​of the first pressure sensor and the second pressure sensor, so that the rod chamber of the lifting cylinder group is connected with the rod chamber of the recovery cylinder group; the control console selectively controls the three-position six-way solenoid reversing valve and the first two-position two-way solenoid valve according to the detection values ​​of the first pressure sensor and the second pressure sensor, so that the power unit is connected with the rod chamber of the recovery cylinder group.

[0015] Furthermore, when a forklift is moving a load from a high place to a low place or when the forklift is descending without a load, if p r <p m And p l＞ p r The control console controls the second two-position two-way solenoid valve to connect the rod chamber of the lifting cylinder group with the rod chamber of the recovery cylinder group, and the control console controls the fourth two-position two-way solenoid reversing valve to connect the rodless chamber of the lifting cylinder group with the rodless chamber of the recovery cylinder group, so as to convert the potential energy released during the load or forklift's unloaded descent into the potential energy of the slider; wherein, p r is the detection value of the second pressure sensor, p m The pressure at which the relief valve is set, p l is the detection value of the first pressure sensor;

[0016] If p r =p m or l ≤p r The control console controls the third two-position two-way solenoid reversing valve to connect the rod chamber of the lifting cylinder group with the hydraulic oil tank; the control console controls the SB2 electromagnetic coil of the three-position six-way solenoid valve to be energized, so that the A port is connected to the P port and the B port is connected to the T port respectively, so that the rodless chamber of the lifting cylinder group is connected to the hydraulic oil tank, which is used to lower the load or the empty forklift to the target height.

[0017] Furthermore, when a forklift is moving a load from a low place to a high place or when the forklift is rising without a load, when p r =0, the control console controls the third two-position two-way solenoid reversing valve to connect the rod chamber of the lifting cylinder group with the hydraulic oil tank, and the control console controls the SB1 solenoid coil of the three-position six-way solenoid valve to be energized, so that the A port is connected to the T port and the B port is connected to the P port respectively, so as to make the load or the forklift empty-loaded rise through the hydraulic power unit;

[0018] If p r >0, the control console controls the first two-position two-way solenoid reversing valve, the third two-position two-way solenoid reversing valve, and the fourth two-position two-way solenoid reversing valve to be energized, the C port and the D port of the three-position six-way solenoid reversing valve are connected, the rodless chamber of the recovery cylinder group is connected with the rodless chamber of the lifting cylinder group through the fourth two-position two-way solenoid reversing valve, and the rod chamber of the recovery cylinder group is connected with the hydraulic power unit through the two-position two-way solenoid valve, the control console controls the engine to provide auxiliary power, and at the same time converts the potential energy of the slider into hydraulic energy, which is used for lifting the load or the forklift without load to the target height.

[0019] The beneficial effects of the present invention are:

[0020] 1. The forklift potential energy recovery and reuse system described in the present invention can alleviate the problems of high fuel consumption and high emissions of traditional forklifts. The potential energy of goods and forks is recovered during the process of the forklift moving goods and forks from a high place to a low place, and the recovered potential energy is released when the goods and forks are lifted, thereby improving the energy utilization efficiency of the forklift and reducing the use cost of the forklift.

[0021] 2. The forklift potential energy recovery and reuse system described in the present invention recovers the potential energy of the forklift during the load lowering process through the slider, and directly uses the recovered potential energy to lift the forklift load. The energy conversion path is short and the energy recovery and reuse efficiency is high.

[0022] 3. The forklift potential energy recovery and reuse system described in the present invention recovers the potential energy during the load lowering process through the slider, which reduces the throttling loss of the hydraulic valve compared with the traditional valve control system, avoids the excessive temperature of the hydraulic system components due to throttling, increases the life of the hydraulic valve, reduces the leakage loss of the hydraulic system, and further improves the energy recovery efficiency.

[0023] 4. The forklift potential energy recovery and reuse system of the present invention is improved on the basis of the original forklift hydraulic system, has a simple structure, and can easily realize low-cost energy-saving transformation of traditional forklifts.

[0024] 5. The forklift potential energy recovery and reuse system described in the present invention can select sliders of different weights to meet the needs of forklifts with different load requirements, and the product coverage is wide. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. The drawings described below are some embodiments of the present invention. For ordinary technicians in this field, it is obvious that other drawings can be obtained based on these drawings without paying any creative work.

[0026] Figure 1This is a schematic diagram of the forklift potential energy recovery and reuse system described in the present invention.

[0027] Figure 2 This is a load increase principle diagram of the present invention.

[0028] Figure 3 This is a schematic diagram of the load reduction energy recovery principle of the present invention.

[0029] Figure 4 This is a load reduction principle diagram of the present invention.

[0030] Figure 5 This is a schematic diagram of the principle of the slider descending to assist the load ascending according to the present invention.

[0031] In the figure:

[0032] 1-engine; 2-speed sensor; 3-ECU; 4-variable displacement hydraulic pump; 5-filter; 6-hydraulic oil tank; 7-first overflow valve; 8-three-position six-way solenoid reversing valve; 9-first pressure sensor; 10-first lifting cylinder; 11-second lifting cylinder; 12-load; 13-first two-position two-way solenoid reversing valve; 14-second two-position two-way solenoid reversing valve; 15-third two-position two-way solenoid reversing valve; 18-slider; 19-first recovery cylinder; 20-second recovery cylinder; 21-second pressure sensor; 22-second overflow valve; 23-fourth two-position two-way solenoid reversing valve. DETAILED DESCRIPTION

[0033] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments, but the protection scope of the present invention is not limited thereto.

[0034] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and should not be construed as limiting the present invention.

[0035] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "axial", "radial", "vertical", "horizontal", "inner", "outer" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", "third", and "fourth" are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first", "second", "third", and "fourth" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "multiple" is two or more, unless otherwise clearly and specifically defined.

[0036] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0037] like Figure 1 As shown, the forklift potential energy recovery and reuse system of the present invention includes a hydraulic drive module, a hydraulic control module and an energy recovery and reuse module;

[0038] The hydraulic drive module includes a first lifting cylinder 10, a second lifting cylinder 11, a hydraulic power unit and a three-position six-way electromagnetic reversing valve 8. The first lifting cylinder 10 and the second lifting cylinder 11 are respectively installed at the bottom of the load 12. The hydraulic power unit includes an engine 1, a variable displacement hydraulic pump 4, a hydraulic oil tank 6 and a second relief valve 7. The engine 1 is used to drive the variable displacement hydraulic pump 4. The inlet of the variable displacement hydraulic pump 4 is connected to the hydraulic oil tank 6. A filter 5 is installed between the inlet of the variable displacement hydraulic pump 4 and the hydraulic oil tank 6. The outlet of the variable displacement hydraulic pump 4 is installed with a first relief valve 7. A speed sensor 2 is installed on the input shaft of the variable displacement hydraulic pump 4 to detect the speed of the variable displacement hydraulic pump 4. The interfaces of the three-position six-way electromagnetic reversing valve 8 include a P port, a T port, a D port, an A port, a B port and a C port. The P port and the D port are respectively connected to the hydraulic power unit, the T port and the A port are connected to the hydraulic oil tank 6, and the C port is connected to the first two-position two-way electromagnetic reversing valve 13. The first lifting cylinder 10 and the second lifting cylinder 11 can be regarded as connected in parallel between the B port and the load 12. The hydraulic power unit is connected to the first lifting cylinder 10 and the second lifting cylinder 11 through the three-position six-way electromagnetic reversing valve 8, so as to make the first lifting cylinder 10 and the second lifting cylinder 11 rise and fall synchronously;

[0039] The potential energy recovery and reuse module includes a first recovery cylinder 19, a second recovery cylinder 20, a first two-position two-way solenoid valve 13, a second two-position two-way solenoid valve 14, a third two-position two-way solenoid valve 15, and a fourth two-position two-way solenoid valve 23; the first recovery cylinder 19 and the second recovery cylinder 20 are used to synchronously push the slider 18; the rodless cavity of the first recovery cylinder 19 and the rodless cavity of the second recovery cylinder 20 intersect and are connected to the rodless cavity of the first lifting cylinder 10 and the second lifting cylinder 11 through the fourth two-position two-way solenoid valve 23, and the rodless cavity of the first lifting cylinder 10 is connected to the rodless cavity of the second lifting cylinder 11 A second overflow valve 22 is installed at the intersection of the rodless chamber; the rod chamber of the first recovery cylinder 19 and the rod chamber of the second recovery cylinder 20 are connected with the rod chamber of the first lifting cylinder 10 and the rod chamber of the second lifting cylinder 11 through the second two-position two-way solenoid valve 14 after the intersection; the rod chamber of the first recovery cylinder 19 and the rod chamber of the second recovery cylinder 20 are connected with the three-position six-way solenoid reversing valve 8 through the first two-position two-way solenoid valve 13; the rod chamber of the first lifting cylinder 10 and the rod chamber of the second lifting cylinder 11 are connected with the hydraulic oil tank 6 through the second two-position two-way solenoid valve 14 and the third two-position two-way solenoid valve 15.

[0040] The control module selectively controls the three-position six-way solenoid reversing valve 8, the first two-position two-way solenoid valve 13, the second two-position two-way solenoid valve 14, the third two-position two-way solenoid valve 15, and the fourth two-position two-way solenoid valve 23, so that the rodless cavity outlets of the first lifting cylinder 10 and the second lifting cylinder 11 are connected with the rodless cavity inlets of the first recovery cylinder 19 and the second recovery cylinder 20, and the rod cavity outlets of the first lifting cylinder 10 and the second lifting cylinder 11 are connected with the rod cavity inlets of the first recovery cylinder 19 and the second recovery cylinder 20, so as to recover the energy of the load 12 during the descending process and release the stored energy when the load 12 rises.

[0041] The following analyzes four typical operating conditions of forklift load reduction, unloaded reduction, load increase, and unloaded increase as embodiments to specifically describe the operation mode of the forklift potential energy recovery system. The embodiments are used to further illustrate the present invention and should not be construed as limiting the scope of protection of the present invention. Some non-essential improvements and adjustments made by technicians in this field based on the above-mentioned contents of the present invention also fall within the scope of protection of the present invention.

[0042] like Figure 2 As shown, when the forklift is moving a load from a low place to a high place or when the forklift is rising empty, when p r =0, the control console 17 controls the third two-position two-way solenoid reversing valve 15 to connect the rod chambers of the first lifting cylinder 10 and the second lifting cylinder 11 with the hydraulic oil tank 6, and the control console 17 controls the SB1 solenoid coil of the three-position six-way solenoid valve 8 to be energized, so that the A port is connected to the T port and the B port is connected to the P port respectively, so as to make the load 12 or the forklift empty-loaded rise through the hydraulic power unit;

[0043] like Figure 5 As shown, when p r >0, the control console 17 controls the first two-position two-way solenoid reversing valve 13, the third two-position two-way solenoid reversing valve 15, and the fourth two-position two-way solenoid reversing valve 23 to be energized, the C port and the D port of the three-position six-way solenoid reversing valve 8 are connected, the rodless chambers of the first recovery cylinder 19 and the second recovery cylinder 20 are connected with the rodless chambers of the first lifting cylinder 10 and the second lifting cylinder 11 through the fourth two-position two-way solenoid reversing valve 23, and the rod chambers of the first recovery cylinder 19 and the second recovery cylinder 20 are connected with the hydraulic power unit through the two-position two-way solenoid valve 13, and the control console 17 controls the engine 1 to provide auxiliary power, and at the same time converts the potential energy of the slider 18 into hydraulic energy, which is used for the load 12 or the forklift to rise to the target height without load.

[0044] like Figure 3 As shown in the figure, when the forklift moves the load from a high place to a low place or the forklift descends empty, when p r <p m And p l＞ p rWhen the control console 17 controls the second two-position two-way solenoid valve 14 to make the rod chambers of the first lifting cylinder 10 and the second lifting cylinder 11 communicate with the rod chambers of the first recovery cylinder 19 and the second recovery cylinder 20, the control console 17 controls the fourth two-position two-way solenoid reversing valve 23 to make the rodless chambers of the first lifting cylinder 10 and the second lifting cylinder 11 communicate with the rodless chambers of the first recovery cylinder 19 and the second recovery cylinder 20, so as to convert the potential energy released during the unloaded descent of the load 12 or the forklift into the potential energy of the slider 18; wherein, p r is the detection value of the second pressure sensor 21, p m Set the pressure of the relief valve 22, p l is the detection value of the first pressure sensor 9; Figure 4 As shown, when p r =p m or l ≤p r The control console 17 controls the third two-position two-way solenoid reversing valve 15 to connect the rod chambers of the first lifting cylinder 10 and the second lifting cylinder 11 with the hydraulic oil tank 6; the control console 17 controls the SB2 electromagnetic coil of the three-position six-way solenoid valve 8 to be energized, so that the A port is connected to the P port and the B port is connected to the T port respectively, so that the rodless chambers of the first lifting cylinder 10 and the second lifting cylinder 11 are connected to the hydraulic oil tank 6, which is used to lower the load 12 or the empty forklift to the target height.

[0045] It should be understood that although this specification is described according to various embodiments, not every embodiment contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

[0046] The series of detailed descriptions listed above are only specific descriptions of feasible embodiments of the present invention. They are not intended to limit the scope of protection of the present invention. All equivalent embodiments or changes that do not deviate from the technical spirit of the present invention should be included in the scope of protection of the present invention.

Claims

1. A forklift potential energy recovery and reuse system, characterized in that: Including hydraulic drive module, hydraulic control module, potential energy recovery and reuse module; The hydraulic drive module comprises a lifting cylinder group (10, 11), a hydraulic power unit and a three-position six-way electromagnetic reversing valve (8); the lifting cylinder group (10, 11) is used to lift a load (12); the hydraulic power unit is connected to the lifting cylinder group (10, 11) via the three-position six-way electromagnetic reversing valve (8) and is used to lift the lifting cylinder group (10, 11); The potential energy recovery and reuse module comprises a recovery cylinder group (19, 20), a three-position six-way electromagnetic reversing valve (8), a first two-position two-way electromagnetic reversing valve (13), a second two-position two-way electromagnetic reversing valve (14), a third two-position two-way electromagnetic reversing valve (15) and a fourth two-position two-way electromagnetic reversing valve (23); the recovery cylinder group (19, 20) is used to push the slider (18); the rodless chamber of the recovery cylinder group (19, 20) is connected to the lifting device through the fourth two-position two-way electromagnetic reversing valve (23). The rodless chambers of the oil cylinder groups (10, 11) are connected; the rod chambers of the recovery oil cylinder groups (19, 20) are connected to the rod chambers of the lifting oil cylinder groups (10, 11) via the second two-position two-way electromagnetic reversing valve (14); the rod chambers of the recovery oil cylinder groups (19, 20) are connected to the three-position six-way electromagnetic reversing valve (8) via the first two-position two-way electromagnetic reversing valve (13); a third two-position two-way electromagnetic reversing valve (15) is provided between the second two-position two-way electromagnetic reversing valve (14) and the hydraulic oil tank (6); The control module selectively controls the three-position six-way electromagnetic reversing valve (8), the first two-position two-way electromagnetic reversing valve (13), the second two-position two-way electromagnetic reversing valve (14), the third two-position two-way electromagnetic reversing valve (15), and the fourth two-position two-way electromagnetic reversing valve (23) to connect the rodless chamber of the lifting cylinder group (10, 11) with the rodless chamber of the recovery cylinder group (19, 20), connect the rod chamber of the recovery cylinder group (19, 20) with the hydraulic pump (4), and connect the rod chamber of the lifting cylinder group (10, 11) with the rod chamber of the recovery cylinder group (19, 20), so as to recover energy during the descending process of the load (12) and release the stored energy when the load (12) rises.

2. The forklift potential energy recovery and reuse system according to claim 1, characterized in that: The hydraulic power unit comprises an engine (1), a hydraulic pump (4), a hydraulic oil tank (6) and a first overflow valve (7); the engine (1) is used to drive the hydraulic pump (4); an oil inlet of the hydraulic pump (4) is connected to the hydraulic oil tank (6); and a first overflow valve (7) is installed at an oil outlet of the hydraulic pump (4).

3. The forklift potential energy recovery and reuse system according to claim 1, characterized in that: The interfaces of the three-position six-way electromagnetic reversing valve (8) include a P port, a T port, a D port, an A port, a B port, and a C port. The P port and the D port are respectively connected to the hydraulic power unit, the A port and the T port are connected to the hydraulic oil tank (6), the B port is connected to the rodless chamber of the lifting cylinder group (10, 11) through the fourth two-position two-way electromagnetic reversing valve (23), and the C port is connected to the first two-position two-way electromagnetic reversing valve (13).

4. The forklift potential energy recovery and reuse system according to claim 1, characterized in that: The sliding block (18) is a forklift balancing block.

5. The forklift potential energy recovery and reuse system according to claim 3, characterized in that: The hydraulic control module comprises a first pressure sensor (9), a second pressure sensor (21) and a control console (17); the first pressure sensor (9) is used to detect the working pressure of the rodless chamber of the lifting cylinder group (10, 11), and the second pressure sensor (21) is used to detect the working pressure of the rodless chamber of the recovery cylinder group (19, 20); the control console (17) selectively controls the three-position six-way electromagnetic reversing valve (8) and the fourth two-position two-way electromagnetic reversing valve (23) according to the detection values ​​of the first pressure sensor (9) and the second pressure sensor (21), so that the rodless chamber of the lifting cylinder group (10, 11) and the recovery cylinder group (19, 20) are connected. The rodless chambers of the cylinder groups (19, 20) are connected; the control console (17) selectively controls the second two-position two-way electromagnetic reversing valve (14) based on the detection values ​​of the first pressure sensor (9) and the second pressure sensor (21), so that the rod chambers of the lifting cylinder groups (10, 11) are connected with the rod chambers of the recovery cylinder groups (19, 20); the control console (17) selectively controls the three-position six-way electromagnetic reversing valve (8) and the first two-position two-way electromagnetic reversing valve (13) based on the detection values ​​of the first pressure sensor (9) and the second pressure sensor (21), so that the power unit is connected with the rod chambers of the recovery cylinder groups (19, 20).

6. The forklift potential energy recovery and reuse system according to claim 5, characterized in that: When a forklift is moving a load from a high place to a low place or when the forklift is descending without a load, p r <p m and p l＞ p r The control console (17) controls the second two-position two-way electromagnetic reversing valve (14) to connect the rod chamber of the lifting cylinder group (10, 11) with the rod chamber of the recovery cylinder group (19, 20), and the control console (17) controls the fourth two-position two-way electromagnetic reversing valve (23) to connect the rodless chamber of the lifting cylinder group (10, 11) with the rodless chamber of the recovery cylinder group (19, 20), so as to convert the potential energy released during the load (12) or the unloaded forklift into the potential energy of the slider (18); wherein, p r is the detection value of the second pressure sensor (21), p m Set the pressure of the relief valve (22). p l is the detection value of the first pressure sensor (9); like p r =p m or p l ≤ p r The control console (17) controls the third two-position two-way electromagnetic reversing valve (15) to connect the rod chamber of the lifting cylinder group (10, 11) with the hydraulic oil tank (6); the control console (17) controls the SB2 electromagnetic coil of the three-position six-way electromagnetic reversing valve (8) to be energized to connect the A port with the P port and the B port with the T port respectively, so that the rodless chamber of the lifting cylinder group (10, 11) is connected with the hydraulic oil tank (6), so as to lower the load (12) or the unloaded forklift to the target height.

7. The forklift potential energy recovery and reuse system according to claim 5, characterized in that: When a forklift is moving a load from a low place to a high place or when the forklift is ascending without a load, p r = 0 The control console (17) controls the third two-position two-way electromagnetic reversing valve (15) to connect the rod chamber of the lifting cylinder group (10, 11) with the hydraulic oil tank (6), and the control console (17) controls the SB1 electromagnetic coil of the three-position six-way electromagnetic reversing valve (8) to be energized, so that the A port is connected to the T port and the B port is connected to the P port respectively, so as to make the load (12) or the forklift empty-loaded rise through the hydraulic power unit; if p r > 0 The control console (17) controls the first two-position two-way electromagnetic reversing valve (13), the third two-position two-way electromagnetic reversing valve (15), and the fourth two-position two-way electromagnetic reversing valve (23) to be energized, the C port and the D port of the three-position six-way electromagnetic reversing valve (8) are connected, the rodless chamber of the recovery cylinder group (19, 20) is connected to the rodless chamber of the lifting cylinder group (10, 11) through the fourth two-position two-way electromagnetic reversing valve (23), and the rod chamber of the recovery cylinder group (19, 20) is connected to the hydraulic power unit through the two-position two-way electromagnetic reversing valve (13), and the control console (17) controls the engine (1) to provide auxiliary power, and at the same time converts the potential energy of the slider (18) into hydraulic energy, which is used to lift the load (12) or the forklift without load to the target height.

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