Energy recovery and load holding system and valve block for electric forklift

Abstract

The embodiment of the utility model provides an energy recovery and load holding system for an electric forklift and a valve block, and belongs to the technical field of electric forklifts. The system comprises a pilot oil source switch solenoid valve, a load control valve and an energy recovery pipeline, one end of the pilot oil source switch solenoid valve is connected with one end of a first pilot oil port to form a first pilot oil way, and the other end of the pilot oil source switch solenoid valve is connected with one end of a second pilot oil port; the first end of the load control valve is connected with the other end of the second pilot oil port to form a second pilot oil way, the second end of the load control valve is connected with the third pilot oil port, the third end of the load control valve is connected with the fourth pilot oil port, and the fourth end of the load control valve is connected with the first oil drainage hole; one end of the energy recovery pipeline is connected with the fourth pilot oil port, and the other end of the energy recovery pipeline is connected with the motor. The system and the valve block are simple in structure and high in energy recovery efficiency.

Description

Technical Field

[0001] The utility model relates to the technical field of electric forklifts, in particular to an energy recovery and load holding system and a valve block for electric forklifts. Background Art

[0002] Forklifts are industrial handling vehicles, which refer to various wheeled handling vehicles for loading, unloading, stacking and short-distance transportation of palletized goods. Forklifts are widely used in ports, stations, airports, freight yards, factory workshops, warehouses, circulation centers and distribution centers, etc., for loading, unloading and handling of palletized goods in cabins, carriages and containers, and are indispensable equipment in pallet transportation and container transportation.

[0003] In response to the national clean energy policy, major manufacturers have launched electric forklifts. The new technology used in the hydraulic system of electric forklifts is the potential energy recovery of the fork descent. The main problems with the energy recovery technology of electric forklifts are: (1) complex structure, high cost, and slow energy recovery return; (2) low recovery rate, and some manufacturers' energy recovery cannot achieve full recovery of descent energy; (3) poor synchronization. The energy recovery solution of some manufacturers is to add a valve block to the bottom of each lifting cylinder. Due to the difference in the signal source and the valve block itself, the two valve blocks will open inconsistently, affecting the synchronization performance of the lifting cylinder. Utility Model Content

[0004] The purpose of the embodiment of the utility model is to provide an energy recovery and load holding system and a valve block for an electric forklift. The system and the valve block have simple structures and can solve the problem of slow energy recovery return.

[0005] In order to achieve the above-mentioned object, the embodiment of the utility model provides an energy recovery and load holding system for an electric forklift, the system comprising:

[0006] A pilot oil source switch solenoid valve, one end of which is connected to one end of the first pilot oil port to form a first pilot oil circuit, and the other end of which is connected to one end of the second pilot oil port;

[0007] A load control valve, wherein a first end of the load control valve is connected to the other end of the second pilot oil port to form a second pilot oil circuit, a second end of the load control valve is connected to the third pilot oil port, a third end of the load control valve is connected to the fourth pilot oil port, and a fourth end of the load control valve is connected to the first oil drain hole;

[0008] An energy recovery pipeline, one end of which is connected to the fourth pilot oil port, and the other end of which is connected to the motor.

[0009] Optionally, the system also includes a proportional pressure reducing valve, a first end of the proportional pressure reducing valve is connected to the other end of the second pilot oil port to form a third pilot oil circuit, a second end of the proportional pressure reducing valve is connected to the first end of the load controller to form a fourth pilot oil circuit, and a third end of the proportional pressure reducing valve is connected to the second oil drain hole.

[0010] Optionally, the load control valve includes: a first load control valve, the first load control valve, the first end of the first load control valve is connected to one end of the fourth pilot oil circuit to form a fifth pilot oil circuit, the second end of the first load control valve is connected to the fifth pilot oil port to form a sixth pilot oil circuit, the third end of the first load control valve is connected to the seventh pilot oil port to form a seventh pilot oil circuit, and the fourth end of the first load control valve is connected to the first oil drain hole.

[0011] Optionally, the load control valve also includes a second load control valve, a first end of the second load control valve is connected to one end of the fourth pilot oil circuit to form an eighth pilot oil circuit, a second end of the second load control valve is connected to the sixth pilot oil port to form a ninth pilot oil circuit, a third end of the second load control valve is connected to the eighth pilot oil port to form a tenth pilot oil circuit, and a fourth end of the second load control valve is connected to the first oil drain hole.

[0012] Optionally, the other end of the first pilot oil port is connected to a pilot oil source; the other end of the third pilot oil port is connected to a lifting cylinder.

[0013] On the other hand, the utility model also includes an energy recovery and load holding valve block for an electric forklift, the valve block comprising:

[0014] A pilot oil source switch solenoid valve, one end of which is connected to one end of the first pilot oil port to form a first pilot oil circuit, and the other end of which is connected to one end of the second pilot oil port;

[0015] A load control valve, wherein a first end of the load control valve is connected to the other end of the second pilot oil port to form a second pilot oil circuit, a second end of the load control valve is connected to the third pilot oil port, a third end of the load control valve is connected to the fourth pilot oil port, and a fourth end of the load control valve is connected to the first oil drain hole;

[0016] an energy recovery pipeline, one end of which is connected to the fourth pilot oil port, and the other end of which is connected to the motor;

[0017] A valve body, wherein the top surface of the valve body is provided with a pilot oil source switch solenoid valve interface, a load control valve interface and an energy recovery pipeline interface, the pilot oil source switch solenoid valve interface is connected to the pilot oil source switch solenoid valve, the load control valve interface is connected to the load control valve, and the energy recovery pipeline interface is connected to the energy recovery pipeline.

[0018] Optionally, the valve block also includes a proportional pressure reducing valve, a first end of the proportional pressure reducing valve is connected to the other end of the second pilot oil port to form a third pilot oil circuit, a second end of the proportional pressure reducing valve is connected to the first end of the load controller to form a fourth pilot oil circuit, and a third end of the proportional pressure reducing valve is connected to the second oil drain hole.

[0019] Optionally, the load control valve includes a first load control valve, a first end of the first load control valve is connected to one end of the fourth pilot oil circuit to form a fifth pilot oil circuit, a second end of the first load control valve is connected to the fifth pilot oil port to form a sixth pilot oil circuit, a third end of the first load control valve is connected to the seventh pilot oil port to form a seventh pilot oil circuit, and a fourth end of the first load control valve is connected to the first oil drain hole.

[0020] Optionally, the load control valve also includes a second load control valve, a first end of the second load control valve is connected to one end of the fourth pilot oil circuit to form an eighth pilot oil circuit, a second end of the second load control valve is connected to the sixth pilot oil port to form a ninth pilot oil circuit, a third end of the second load control valve is connected to the eighth pilot oil port to form a tenth pilot oil circuit, and a fourth end of the second load control valve is connected to the first oil drain hole.

[0021] Optionally, the other end of the first pilot oil port is connected to a pilot oil source; the other end of the third pilot oil port is connected to a lifting cylinder.

[0022] Through the above technical scheme, the utility model provides an energy recovery and load holding system and valve block for electric forklifts. When the cargo fork is lifting the cargo and is not moving, the pilot oil source switch solenoid valve is not energized, and the hydraulic oil can only enter from the third pilot oil port. At this time, the one-way valve inside the load control valve is in a cut-off state, and the cargo cannot be lowered, thereby realizing the load holding state. When energy recovery is performed during descent, the pilot oil enters the first pilot oil circuit from the first pilot oil port. At this time, the pilot oil source switch solenoid valve is energized, and the pilot oil passes through the second pilot oil circuit to push the load control valve, so that the load control valve is opened. At this time, the hydraulic oil enters the fourth pilot oil circuit from the third pilot oil port to enter the motor, and push the motor to rotate, thereby driving the motor to recover energy. This system and valve block have a simple structure and high energy recovery efficiency. In the prior art, the load control valve is placed in different valve bodies. Due to the difference in signal sources and the valve blocks themselves, the opening of the two valve blocks will be inconsistent, thereby affecting the synchronization performance of the lifting cylinder. In the utility model, the load control valve is arranged in the same valve body, the load control valve is always open, and the lifting cylinder has higher synchronization in controlling the load control valve.

[0023] Other features and advantages of the embodiments of the present invention will be described in detail in the subsequent specific implementation section. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The accompanying drawings are used to provide a further understanding of the embodiments of the present utility model and constitute a part of the specification. Together with the following specific implementations, they are used to explain the embodiments of the present utility model, but do not constitute a limitation on the embodiments of the present utility model. In the accompanying drawings:

[0025] Figure 1 is a schematic diagram of an energy recovery and load holding system for an electric forklift according to one embodiment of the utility model;

[0026] Figure 2 is a schematic diagram of an energy recovery and load holding system for an electric forklift according to one embodiment of the utility model;

[0027] Figure 3 is a schematic diagram of an energy recovery and load holding valve block for an electric forklift according to one embodiment of the utility model;

[0028] Figure 4 It is a schematic diagram of a pilot oil source switch solenoid valve in an energy recovery and load holding valve block for an electric forklift according to one embodiment of the utility model;

[0029] Figure 5 is a schematic diagram of an energy recovery and load holding valve block for an electric forklift according to one embodiment of the utility model;

[0030] Figure 6 It is a schematic diagram of a second pilot oil circuit in an energy recovery and load holding valve block for an electric forklift according to one embodiment of the utility model;

[0031] Figure 7 It is a schematic diagram of a fourth pilot oil circuit in an energy recovery and load holding valve block for an electric forklift according to an embodiment of the utility model;

[0032] Figure 8 The diagram is a schematic diagram of an energy recovery and load holding valve block for an electric forklift according to an embodiment of the utility model.

[0033] Description of Reference Numerals

[0034] 1. Pilot oil source switch solenoid valve 2. Load control valve

[0035] 3. Energy recovery pipeline 4. Proportional pressure reducing valve

[0036] 5. Valve body 21, first load control valve

[0037] 22. Second load control valve LS, first pilot oil port

[0038] 2Y, second pilot oil port A, third pilot oil port

[0039] B. Fourth pilot oil port A1, fifth pilot oil port

[0040] A2, sixth pilot oil port B1, seventh pilot oil port

[0041] B2, eighth pilot oil port Y, first oil drain hole

[0042] T, second oil drain hole 1A, first pilot oil circuit

[0043] 1C, second pilot oil circuit 1D, third pilot oil circuit

[0044] 1F, fourth pilot oil circuit 1G, fifth pilot oil circuit

[0045] 1H, sixth pilot oil circuit 1J, seventh pilot oil circuit

[0046] 1K, the eighth pilot oil circuit 1L, the ninth pilot oil circuit

[0047] 1W, tenth pilot oil circuit DETAILED DESCRIPTION

[0048] The specific implementation of the embodiment of the utility model is described in detail below in conjunction with the accompanying drawings. It should be understood that the specific implementation described here is only used to illustrate and explain the embodiment of the utility model, and is not used to limit the embodiment of the utility model.

[0049] In the embodiments of the present application, unless otherwise specified, directional words such as "up, down, top, bottom" are usually used with reference to the directions shown in the drawings or are used to describe the relative positional relationships of components in the vertical, perpendicular or gravity direction.

[0050] In addition, if there are descriptions involving "first", "second", etc. in the implementation methods of this application, the descriptions of "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or suggesting their relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the technical solutions between the various implementation methods can be combined with each other, but they must be based on the ability of ordinary technicians in the field to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by this application.

[0051] like Figure 1 and 2 As shown, Figure 1 and Figure 2 Each of them is a schematic diagram of an energy recovery and load holding system and a valve block for an electric forklift according to an embodiment of the utility model. Figure 1 The system includes: a pilot oil source switch solenoid valve 1, a load control valve 2 and an energy recovery pipeline 3, wherein one end of the pilot oil source switch solenoid valve 1 is connected to one end of the first pilot oil port LS to form a first pilot oil circuit 1G, and the other end of the pilot oil source switch solenoid valve 1 is connected to one end of the second pilot oil port 2Y; the first end of the load control valve 2 is connected to the other end of the second pilot oil port 2Y to form a second pilot oil circuit 1C, the second end of the load control valve 2 is connected to the third pilot oil port A, the third end of the load control valve 2 is connected to the fourth pilot oil port B, and the fourth end of the load control valve 2 is connected to the first oil drain hole Y; one end of the energy recovery pipeline 3 is connected to the fourth pilot oil port B, and the other end of the energy recovery pipeline 3 is connected to the motor. When the fork lifts the goods and does not move, the pilot oil source switch solenoid valve 1 is not energized, and the hydraulic oil can only enter from the third pilot oil port A. At this time, the one-way valve inside the load control valve 2 is in a cut-off state, and the goods cannot be lowered, realizing the load holding state. When descending energy recovery is performed, the pilot oil enters the first pilot oil circuit 1G from the first pilot oil port LS. At this time, the pilot oil source switch solenoid valve 1 is energized, and the pilot oil passes through the second pilot oil circuit 1C to push the load control valve 2, so that the load control valve 2 opens. At this time, the hydraulic oil enters the fourth pilot oil port B from the third pilot oil port A to enter the motor, driving the motor to rotate, thereby driving the motor to recover energy.

[0052] In this embodiment, the type of the pilot oil source switch solenoid valve 1 can be a variety known to those skilled in the art. In one embodiment of the utility model, the pilot oil source switch solenoid valve 1 is a two-position two-way solenoid valve. When the pilot oil source switch solenoid valve 1 is not energized, the pilot pressure oil is blocked outside and cannot enter the first pilot oil circuit LS to push the valve core. After the pilot oil source switch solenoid valve 1 is energized, the first pilot oil circuit LS is opened.

[0053] In this embodiment, considering that different currents will lead to different control output pressures, in the present utility model, the system further includes a proportional pressure reducing valve 4, a first end of the proportional pressure reducing valve 4 is connected to the second pilot oil port 2Y to form a third pilot oil circuit 1G, a second end of the proportional pressure reducing valve 4 is connected to the second end of the load control valve 2 to form a fourth pilot oil circuit 1F, and a third end of the proportional pressure reducing valve 4 is connected to the second oil drain hole T. When the pilot oil enters the proportional pressure reducing valve 4, the proportional pressure reducing valve 4 determines the output pressure according to the current, thereby controlling the opening size of the load control valve 2 to control its descending speed.

[0054] In this embodiment, the structure of the load control valve 2 can be various known to those skilled in the art. In one embodiment of the present utility model, the load control valve 2 includes a first load control valve 21 and a second load control valve 22, wherein a first end of the first load control valve 21 is connected to one end of the fourth pilot oil circuit 1F to form a fifth pilot oil circuit 1G, a second end of the first load control valve 21 is connected to the fifth pilot oil port A1 to form a sixth pilot oil circuit 1H, and a third end of the first load control valve 21 is connected to the seventh pilot oil port A2 to form a sixth pilot oil circuit 1H. The oil port B1 is connected to form the seventh pilot oil circuit 1J, the fourth end of the first load control valve 21 is connected to the first oil drain hole Y; the first end of the second load control valve 22 is connected to the fourth pilot oil circuit 1F to form the eighth pilot oil circuit 1K, the second end of the second load control valve 22 is connected to the sixth pilot oil port A2 to form the ninth pilot oil circuit 1L, the third end of the second load control valve 22 is connected to the eighth pilot oil port B2 to form the tenth pilot oil circuit 1W, and the fourth end of the second load control valve 22 is connected to the first oil drain hole Y. The fifth pilot oil circuit 1G and the seventh pilot oil circuit 1J are connected to each other, and the sixth pilot oil circuit 1H and the eighth pilot oil circuit 1K are connected to each other. The second pilot oil circuit 1C includes the third pilot oil circuit 1D and the fourth pilot oil circuit 1F.

[0055] In this embodiment, the other end of the first pilot oil port LS is connected to the pilot oil source, and the other end of the third pilot oil port A is connected to the lifting cylinder.

[0056] When the fork is lifting the cargo and is not moving, the pilot oil source switch solenoid valve 1 and the proportional pressure reducing valve 4 shall not be energized. Due to the cut-off effect of the one-way valves in the first load control valve 21 and the second load control valve 22, the hydraulic oil cannot return from the oil ports of other oil circuits. At this time, the hydraulic oil can only enter the fifth pilot oil port A1 and the sixth pilot oil port A2. At this time, the one-way valves in the first load control valve 21 and the second load control valve 22 are in the cut-off state, and the cargo cannot be lowered. Therefore, the load holding state can be achieved. When descending energy recovery is performed, the pilot pressure oil enters the first pilot oil circuit 1A from the first pilot oil port LS. At this time, the pilot oil source switch solenoid valve 1 is energized, and the pilot oil passes through the third pilot oil circuit 1D from the second pilot oil port 2Y to the proportional pressure reducing valve 4. The proportional pressure reducing valve 4 determines the size of the output pressure according to the size of the current. The pilot hydraulic oil output by the proportional pressure reducing valve 4 passes through the fourth pilot oil circuit 1F to push the first load control valve 21 and the second load control valve 22, so that the first load control valve 21 and the second load control valve 22 are opened. At this time, the valve cores of the first load control valve 21 and the second load control valve 22 have been opened under the action of the pilot hydraulic oil output by the proportional pressure reducing valve 4. The hydraulic oil in the lifting cylinder enters the sixth pilot oil circuit 1H and the ninth pilot oil circuit 1L from the fifth pilot oil port A1 and the sixth pilot oil port A2, and then enters the seventh pilot oil port B1 and the eighth pilot oil port B2 through the seventh pilot oil circuit 1J and the tenth pilot oil circuit 1W, and enters the motor, pushing the motor to rotate and drive the motor to recover energy.

[0057] In addition, the utility model also includes an energy recovery and load holding valve block for an electric forklift, such as Figures 3 to 8 As shown, the valve block includes a pilot oil source switch solenoid valve 1, a load control valve 2, an energy recovery pipeline 3 and a valve body 5, wherein one end of the pilot oil source switch solenoid valve 1 is connected to one end of the first pilot oil port LS to form a first pilot oil circuit 1G, and the other end of the pilot oil source switch solenoid valve 1 is connected to one end of the second pilot oil port 2Y; the first end of the load control valve 2 is connected to the other end of the second pilot oil port 2Y to form a second pilot oil circuit 1C, and the second end of the load control valve 2 is connected to the third pilot oil port A, and the load control The third end of the valve 2 is connected to the fourth pilot oil port B, and the fourth end of the load control valve 2 is connected to the first oil drain hole Y; one end of the energy recovery pipeline 3 is connected to the fourth pilot oil port B, and the other end of the energy recovery pipeline 3 is connected to the motor; the top surface of the valve body 5 is provided with a pilot oil source switch solenoid valve interface, a load control valve interface and an energy recovery pipeline interface, the pilot oil source switch solenoid valve interface is connected to the pilot oil source switch solenoid valve 1, the load control valve interface is connected to the load control valve 2, and the energy recovery pipeline interface is connected to the energy recovery pipeline 3.

[0058] When the fork lifts the goods and does not move, the pilot oil source switch solenoid valve 1 is not energized, and the hydraulic oil can only enter from the third pilot oil port A. At this time, the one-way valve inside the load control valve 2 is in the cut-off state, and the goods cannot be lowered, so the load is kept in the state. When the energy recovery is performed during the descent, the pilot oil enters the first pilot oil circuit 1G from the first pilot oil port LS. At this time, the pilot oil source switch solenoid valve 1 is energized, and the pilot oil passes through the second pilot oil circuit 1C to push the load control valve 2, so that the load control valve 2 opens. At this time, the hydraulic oil enters the fourth pilot oil port B from the third pilot oil port A to enter the motor, drive the motor to rotate, and thus drive the motor to recover energy.

[0059] In this embodiment, the type of the pilot oil source switch solenoid valve 1 can be a variety known to those skilled in the art. In one embodiment of the utility model, the pilot oil source switch solenoid valve 1 is a two-position two-way solenoid valve. When the pilot oil source switch solenoid valve 1 is not energized, the pilot pressure oil is blocked outside and cannot enter the first pilot oil circuit LS to push the valve core. After the pilot oil source switch solenoid valve 1 is energized, the first pilot oil circuit LS is opened.

[0060] In this embodiment, considering that different currents will lead to different control output pressures, in the present utility model, the system further includes a proportional pressure reducing valve 4, a first end of the proportional pressure reducing valve 4 is connected to the second pilot oil port 2Y to form a third pilot oil circuit 1G, a second end of the proportional pressure reducing valve 4 is connected to the second end of the load control valve 2 to form a fourth pilot oil circuit 1F, and a third end of the proportional pressure reducing valve 4 is connected to the second oil drain hole T. When the pilot oil enters the proportional pressure reducing valve 4, the proportional pressure reducing valve 4 determines the output pressure according to the current, thereby controlling the opening size of the load control valve 2 to control its descending speed.

[0061] In this embodiment, the structure of the load control valve 2 can be various known to those skilled in the art. In one embodiment of the present utility model, the load control valve 2 includes a first load control valve 21 and a second load control valve 22, wherein a first end of the first load control valve 21 is connected to one end of the fourth pilot oil circuit 1F to form a fifth pilot oil circuit 1G, a second end of the first load control valve 21 is connected to the fifth pilot oil port A1 to form a sixth pilot oil circuit 1H, and a third end of the first load control valve 21 is connected to the seventh pilot oil port A2 to form a sixth pilot oil circuit 1H. The oil port B1 is connected to form the seventh pilot oil circuit 1J, the fourth end of the first load control valve 21 is connected to the first oil drain hole Y; the first end of the second load control valve 22 is connected to the fourth pilot oil circuit 1F to form the eighth pilot oil circuit 1K, the second end of the second load control valve 22 is connected to the sixth pilot oil port A2 to form the ninth pilot oil circuit 1L, the third end of the second load control valve 22 is connected to the eighth pilot oil port B2 to form the tenth pilot oil circuit 1W, and the fourth end of the second load control valve 22 is connected to the first oil drain hole Y. The fifth pilot oil circuit 1G and the seventh pilot oil circuit 1J are connected to each other, and the sixth pilot oil circuit 1H and the eighth pilot oil circuit 1K are connected to each other. The second pilot oil circuit 1C includes the third pilot oil circuit 1D and the fourth pilot oil circuit 1F.

[0062] In this embodiment, the other end of the first pilot oil port LS is connected to the pilot oil source, and the other end of the third pilot oil port A is connected to the lifting cylinder.

[0063] When the fork is lifting the cargo and is not moving, the pilot oil source switch solenoid valve 1 and the proportional pressure reducing valve 4 shall not be energized. Due to the cut-off effect of the one-way valves in the first load control valve 21 and the second load control valve 22, the hydraulic oil cannot return from the oil ports of other oil circuits. At this time, the hydraulic oil can only enter the fifth pilot oil port A1 and the sixth pilot oil port A2. At this time, the one-way valves in the first load control valve 21 and the second load control valve 22 are in the cut-off state, and the cargo cannot be lowered. Therefore, the load holding state can be achieved. When descending energy recovery is performed, the pilot pressure oil enters the first pilot oil circuit 1A from the first pilot oil port LS. At this time, the pilot oil source switch solenoid valve 1 is energized, and the pilot oil passes through the third pilot oil circuit 1D from the second pilot oil port 2Y to the proportional pressure reducing valve 4. The proportional pressure reducing valve 4 determines the size of the output pressure according to the size of the current. The pilot hydraulic oil output by the proportional pressure reducing valve 4 passes through the fourth pilot oil circuit 1F to push the first load control valve 21 and the second load control valve 22, so that the first load control valve 21 and the second load control valve 22 are opened. At this time, the valve cores of the first load control valve 21 and the second load control valve 22 have been opened under the action of the pilot hydraulic oil output by the proportional pressure reducing valve 4. The hydraulic oil in the lifting cylinder enters the sixth pilot oil circuit 1H and the ninth pilot oil circuit 1L from the fifth pilot oil port A1 and the sixth pilot oil port A2, and then enters the seventh pilot oil port B1 and the eighth pilot oil port B2 through the seventh pilot oil circuit 1J and the tenth pilot oil circuit 1W, and enters the motor, pushing the motor to rotate and drive the motor to recover energy.

[0064] Through the above technical solution, the utility model provides an energy recovery and load holding system and valve block for electric forklifts. When the cargo fork is lifting the cargo and is not moving, the pilot oil source switch solenoid valve 1 is not energized, and the hydraulic oil can only enter from the third pilot oil port A. At this time, the one-way valve inside the load control valve 2 is in a cut-off state, and the cargo cannot be lowered, thereby realizing the load holding state. When descending energy recovery is performed, the pilot oil enters the first pilot oil circuit 1G from the first pilot oil port LS. At this time, the pilot oil source switch solenoid valve 1 is energized, and the pilot oil passes through the second pilot oil circuit 1C to push the load control valve 2, so that the load control valve 2 is opened. At this time, the hydraulic oil enters the fourth pilot oil port B from the third pilot oil port A to enter the motor, and push the motor to rotate, thereby driving the motor to recover energy. This system and valve block have a simple structure and high energy recovery efficiency. In the prior art, the load control valve 2 is placed in different valve bodies. Due to the difference in signal sources and the valve blocks themselves, the opening of the two valve blocks will be inconsistent, thereby affecting the synchronization performance of the lifting cylinder. In the utility model, the load control valve 2 is arranged in the same valve body, the load control valve 2 is always open, and the lifting cylinder has higher synchronization in controlling the load control valve 2.

[0065] The optional implementation modes of the utility model examples are described in detail above in conjunction with the accompanying drawings. However, the implementation modes of the utility model are not limited to the specific details in the above implementation modes. Within the technical concept of the implementation modes of the utility model, various simple modifications can be made to the technical solutions of the implementation modes of the utility model. These simple modifications all belong to the protection scope of the implementation modes of the utility model.

[0066] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the various possible combinations of the embodiments of the present utility model will not be described separately.

[0067] In addition, various different embodiments of the present invention may be arbitrarily combined, and as long as they do not violate the concept of the present invention, they should also be regarded as the contents disclosed in the embodiments of the present invention.

Claims

1. An energy recovery and load holding system for an electric forklift, characterized in that: The system comprises: A pilot oil source switch solenoid valve, one end of which is connected to one end of the first pilot oil port to form a first pilot oil circuit, and the other end of which is connected to one end of the second pilot oil port; A load control valve, wherein a first end of the load control valve is connected to the other end of the second pilot oil port to form a second pilot oil circuit, a second end of the load control valve is connected to the third pilot oil port, a third end of the load control valve is connected to the fourth pilot oil port, and a fourth end of the load control valve is connected to the first oil drain hole; An energy recovery pipeline, one end of which is connected to the fourth pilot oil port, and the other end of which is connected to the motor.

2. The system according to claim 1, characterized in that The system also includes a proportional pressure reducing valve, a first end of the proportional pressure reducing valve is connected to the other end of the second pilot oil port to form a third pilot oil circuit, a second end of the proportional pressure reducing valve is connected to the first end of the load control valve to form a fourth pilot oil circuit, and a third end of the proportional pressure reducing valve is connected to the second oil drain hole.

3. The system according to claim 2, characterized in that The load control valve includes a first load control valve, a first end of the first load control valve is connected to one end of the fourth pilot oil circuit to form a fifth pilot oil circuit, a second end of the first load control valve is connected to a fifth pilot oil port to form a sixth pilot oil circuit, a third end of the first load control valve is connected to a seventh pilot oil port to form a seventh pilot oil circuit, and a fourth end of the first load control valve is connected to a first oil drain hole.

4. The system according to claim 3, characterized in that The load control valve also includes a second load control valve, a first end of the second load control valve is connected to one end of the fourth pilot oil circuit to form an eighth pilot oil circuit, a second end of the second load control valve is connected to a sixth pilot oil port to form a ninth pilot oil circuit, a third end of the second load control valve is connected to an eighth pilot oil port to form a tenth pilot oil circuit, and a fourth end of the second load control valve is connected to the first oil drain hole.

5. The system according to claim 1, characterized in that The other end of the first pilot oil port is connected to the pilot oil source; the other end of the third pilot oil port is connected to the lifting cylinder.

6. An energy recovery and load holding valve block for an electric forklift, characterized in that: The valve block comprises: A pilot oil source switch solenoid valve, one end of which is connected to one end of the first pilot oil port to form a first pilot oil circuit, and the other end of which is connected to one end of the second pilot oil port; A load control valve, wherein a first end of the load control valve is connected to the other end of the second pilot oil port to form a second pilot oil circuit, a second end of the load control valve is connected to the third pilot oil port, a third end of the load control valve is connected to the fourth pilot oil port, and a fourth end of the load control valve is connected to the first oil drain hole; an energy recovery pipeline, one end of which is connected to the fourth pilot oil port, and the other end of which is connected to the motor; A valve body, wherein the top surface of the valve body is provided with a pilot oil source switch solenoid valve interface, a load control valve interface and an energy recovery pipeline interface, the pilot oil source switch solenoid valve interface is connected to the pilot oil source switch solenoid valve, the load control valve interface is connected to the load control valve, and the energy recovery pipeline interface is connected to the energy recovery pipeline.

7. The valve block according to claim 6, characterized in that: The valve block also includes a proportional pressure reducing valve, a first end of the proportional pressure reducing valve is connected to the other end of the second pilot oil port to form a third pilot oil circuit, a second end of the proportional pressure reducing valve is connected to the first end of the load controller to form a fourth pilot oil circuit, and a third end of the proportional pressure reducing valve is connected to the second oil drain hole.

8. The valve block according to claim 7, characterized in that: The load control valve includes a first load control valve, a first end of the first load control valve is connected to one end of the fourth pilot oil circuit to form a fifth pilot oil circuit, a second end of the first load control valve is connected to a fifth pilot oil port to form a sixth pilot oil circuit, a third end of the first load control valve is connected to a seventh pilot oil port to form a seventh pilot oil circuit, and a fourth end of the first load control valve is connected to a first oil drain hole.

9. The valve block according to claim 8, characterized in that: The load control valve also includes a second load control valve, a first end of the second load control valve is connected to one end of the fourth pilot oil circuit to form an eighth pilot oil circuit, a second end of the second load control valve is connected to a sixth pilot oil port to form a ninth pilot oil circuit, a third end of the second load control valve is connected to an eighth pilot oil port to form a tenth pilot oil circuit, and a fourth end of the second load control valve is connected to the first oil drain hole.

10. The valve block according to claim 6, characterized in that: The other end of the first pilot oil port is connected to the pilot oil source; the other end of the third pilot oil port is connected to the lifting cylinder.

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