Hydraulic control system and working machine

Abstract

This utility model belongs to the field of hydraulic technology, specifically relating to a hydraulic control system and a working machine. The hydraulic control system includes: an oil supply circuit, comprising an inlet oil circuit, a steering oil circuit, and a main oil circuit; a priority valve, having a control port, a priority outlet port connected to the steering oil circuit, a secondary outlet port connected to the main oil circuit, and a priority valve inlet port connected to the inlet oil circuit; a steering gear, with its inlet port connected to the steering oil circuit and its pressure feedback port connected to the control port of the priority valve; and a switching valve, with the switching valve and the priority valve connected in parallel, the inlet and outlet ports of which are respectively connected to the inlet oil circuit and the main oil circuit. When the steering gear is in standby mode, the switching valve is open so that hydraulic oil entering from the inlet oil circuit flows into the main oil circuit via the switching valve. Using the above-mentioned hydraulic control system can reduce the energy loss of the steering gear in standby mode and improve the overall efficiency of the working machine.

Description

Technical Field

[0001] This utility model belongs to the field of hydraulic technology, specifically relating to a hydraulic control system and a working machine. Background Technology

[0002] With the rapid development of warehousing, logistics, and manufacturing industries, the demand for efficient and environmentally friendly material handling equipment is increasing daily. Forklifts have experienced rapid growth due to their advantages such as low noise and energy efficiency. The main functions of forklifts are loading, unloading, stacking, short-distance transport, and handling heavy items. For electric forklifts, range is a key performance indicator. Unnecessary pressure losses exist in hydraulic systems, directly wasting energy and thus affecting range.

[0003] Forklift hydraulic control systems typically include a multi-way valve and a steering gear. A priority valve adjusts the ratio of hydraulic oil flow into the steering gear and the multi-way valve based on the steering gear's flow requirements. When the current flow rate of the steering gear does not match the required flow rate, a hydraulic oil signal is transmitted to the control circuit to adjust the valve spool to achieve a balanced position. In the aforementioned prior art, when the steering gear is not in operation, to allow hydraulic oil to flow into the multi-way valve, the spring force of the priority valve needs to be overcome to achieve balance. This process results in energy loss, reducing the range of the electric work machine. Utility Model Content

[0004] The purpose of this invention is to provide a hydraulic control system and working machinery to reduce energy loss of the steering gear in standby mode.

[0005] To achieve the above objectives, this utility model provides a hydraulic control system, comprising:

[0006] The fuel supply system includes the fuel inlet system, the steering system, and the main fuel system.

[0007] The priority valve has a control port, a priority outlet port connected to the steering oil circuit, a secondary outlet port connected to the main oil circuit, and a priority valve inlet port connected to the inlet oil circuit.

[0008] The steering gear has an oil inlet connected to the steering oil circuit and a pressure feedback oil port connected to the control oil port of the priority valve.

[0009] The switching valve and the priority valve are connected in parallel. The oil inlet and outlet of the switching valve are connected to the oil inlet circuit and the main oil circuit, respectively. When the steering gear is in standby mode, the switching valve is turned on so that the hydraulic oil entering from the oil inlet circuit flows into the main oil circuit through the switching valve.

[0010] In some embodiments, the hydraulic control system further includes a control unit electrically connected to both the steering gear and the switching valve, the control unit being used to control the on / off state of the switching valve according to the current state of the steering gear.

[0011] In some implementations, the switching valve is a normally open two-position two-way solenoid valve.

[0012] In some implementations, the priority valve is a hydraulically controlled proportional directional valve. When the steering gear is in operation, the priority valve is used to adjust the flow rate of hydraulic oil from the inlet oil line to the priority outlet and the secondary outlet.

[0013] In some embodiments, the hydraulic proportional directional valve further includes a valve core and a preload member connected to the axial end of the valve core. The preload member is used to apply an axial preload force to the valve core and press the control port against it so that the control port has a preset opening pressure.

[0014] In some embodiments, the hydraulically controlled proportional directional valve has three operating positions. When the hydraulically controlled proportional directional valve is in the first operating position, the priority valve inlet and the priority outlet are connected. When the hydraulically controlled proportional directional valve is in the second operating position, the priority valve inlet, the priority outlet, and the secondary outlet are all connected. When the hydraulically controlled proportional directional valve is in the third operating position, the priority valve inlet and the secondary outlet are connected.

[0015] In some implementations, the hydraulic control system further includes damping in a control circuit connected between the pressure feedback port and the control port.

[0016] In some embodiments, the hydraulic control system further includes: a hydraulic oil tank; a safety valve, wherein the inlet of the safety valve is connected to a control oil circuit between a pressure feedback port and a control port, and the outlet of the safety valve is connected to the hydraulic oil tank.

[0017] In some implementations, the hydraulic control system further includes a multi-way valve assembly, the inlet of which is connected to the main oil circuit, and the working port of which is connected to the oil circuit of the actuator.

[0018] The second aspect of this utility model provides a working machine, including the aforementioned hydraulic control system.

[0019] In the above technical solution, the hydraulic control system includes an oil supply circuit, a priority valve, a steering gear, and a switching valve. The oil supply circuit includes an inlet circuit, a steering circuit, and a main circuit. The priority valve has a control port, a priority outlet port connected to the steering circuit, a secondary outlet port connected to the main circuit, and a priority valve inlet port connected to the inlet circuit. The steering gear inlet port is connected to the steering circuit, and the steering gear pressure feedback port is connected to the priority valve control port. When the steering gear pressure feedback port can feed hydraulic oil back to the control port, the valve core position of the priority valve is adjusted, so that the priority valve can adjust the hydraulic oil flow rate input to the main circuit and the steering circuit according to the hydraulic oil flow rate requirement of the steering gear. The switching valve and the priority valve are connected in parallel. The inlet and outlet of the switching valve are connected to the inlet oil circuit and the main oil circuit, respectively. When the steering gear is in standby mode, the switching valve can be opened so that the hydraulic oil in the inlet oil circuit flows directly into the main oil circuit. The hydraulic oil will no longer flow through the priority valve. This means that when the steering gear is in standby mode, there is no need to consume energy to adjust the valve core position of the priority valve. The steering oil circuit and the inlet oil circuit can be directly disconnected, which reduces the energy loss in the hydraulic control system and improves the response speed of the hydraulic control system.

[0020] Other features and advantages of this invention will be described in detail in the following detailed description section. Attached Figure Description

[0021] The accompanying drawings are provided to further illustrate the embodiments of the present invention and form part of the specification. They are used together with the following detailed description to explain the embodiments of the present invention, but do not constitute a limitation thereof. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without any inventive effort. In the drawings:

[0022] Figure 1 The hydraulic schematic diagram is provided for the hydraulic control system according to the first embodiment of this utility model.

[0023] Figure 2 This is a hydraulic schematic diagram of a hydraulic control system provided according to the second embodiment of the present invention.

[0024] Explanation of reference numerals in the attached figures

[0025] 10 Priority Valve

[0026] 20 Switching valve

[0027] 30-way valve assembly

[0028] 40 Damping

[0029] 50 Safety Valve

[0030] L1 oil inlet circuit

[0031] L2 steering oil circuit

[0032] L3 Main Oil Circuit Detailed Implementation

[0033] The specific embodiments of this utility model will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit the scope of this utility model.

[0034] The hydraulic control system and working machinery according to the present invention are described below with reference to the accompanying drawings.

[0035] like Figure 1 The diagram shown is a hydraulic schematic of a hydraulic control system according to a first embodiment of the present invention. The hydraulic control system provided in this embodiment includes:

[0036] The oil supply circuit includes the inlet oil circuit L1, the steering oil circuit L2, and the main oil circuit L3.

[0037] Priority valve 10 has a control port, a priority outlet port connected to steering oil circuit L2, a secondary outlet port connected to main oil circuit L3, and a priority valve 10 inlet port connected to inlet oil circuit L1.

[0038] The steering gear (not shown in the figure) has its oil inlet connected to the steering oil circuit L2, and its pressure feedback oil port connected to the control oil port of the priority valve 10.

[0039] Switch valve 20 and priority valve 10 are connected in parallel. The oil inlet and oil outlet of switch valve 20 are connected to oil inlet circuit L1 and main oil circuit L3, respectively. When the steering gear is in standby state, switch valve 20 is turned on so that hydraulic oil entering from oil inlet circuit L1 flows into main oil circuit L3 through switch valve 20.

[0040] The priority valve 10 is a key component in a hydraulic control system used to adjust the flow of hydraulic oil according to the needs of the steering gear. It typically includes a control port, a priority outlet, a secondary outlet, and a priority valve 10 inlet. In the prior art, when the steering gear is in operation and requires a certain flow of hydraulic oil, the priority valve 10 senses the pressure feedback from the steering gear and adjusts its valve spool position accordingly to ensure that the flow of hydraulic oil to the steering gear meets the demand. When the steering gear is in standby mode, i.e., when no hydraulic oil is needed for steering operation, the valve spool of the priority valve 10 moves, allowing the hydraulic oil flowing through the priority valve 10 to flow from the secondary outlet to the main oil circuit L3.

[0041] However, in the above structure, when the steering gear is in standby mode, the position of the valve core of the priority valve 10 needs to be adjusted, which usually requires a large amount of energy and results in energy loss. For example, in one embodiment of the prior art, the valve core starts to move when the steering gear enters standby mode, and the valve core reaches the equilibrium position, resulting in an energy loss of 1.4kW.

[0042] The hydraulic control system provided in this embodiment includes an oil supply circuit, a priority valve 10, a steering gear, and a switching valve 20. The oil supply circuit is further designed to include an inlet oil circuit L1, a steering oil circuit L2, and a main oil circuit L3 to ensure the rational distribution and flow direction of the hydraulic oil. The priority valve 10, as the core component of this system, has a control port, a priority outlet port, a secondary outlet port, and a priority valve 10 inlet port. The design of these ports allows the priority valve 10 to flexibly adjust the hydraulic oil flow rate according to the needs of the steering gear. The steering gear inlet port is connected to the steering oil circuit L2, while its pressure feedback port is connected to the control port. This design allows the steering gear to promptly feed back pressure signals to the priority valve 10, thereby adjusting the flow direction and flow rate of the hydraulic oil. The switching valve 20 is connected in parallel with the priority valve 10, with its inlet and outlet ports connected to the inlet oil circuit L1 and the main oil circuit L3, respectively. When the steering gear is in standby mode, the switching valve 20 automatically opens, allowing hydraulic oil entering from the inlet line L1 to flow directly into the main line L3 through the switching valve 20 without passing through the priority valve 10. This is because when the switching valve 20 is open, a nearly unobstructed bypass path is established, allowing hydraulic oil to flow quickly from the switching valve 20 to the main line L3, thus "short-circuiting" the priority valve 10 and preventing hydraulic oil from flowing through it. This design eliminates the need for energy to bring the valve core of the priority valve 10 to a balanced state when the steering gear enters standby mode, significantly reducing energy loss in standby mode and improving the overall efficiency of the hydraulic control system.

[0043] In one embodiment, such as Figure 2 The diagram shown is a hydraulic schematic of a hydraulic control system according to a second embodiment of the present invention. The hydraulic structures in the first and second embodiments are applied in different hydraulic control systems. The first embodiment includes an electro-proportional multi-way valve group 30, and the second embodiment includes a manual multi-way valve group 30.

[0044] In one embodiment, the hydraulic control system further includes a control unit electrically connected to both the steering gear and the switching valve 20. The control unit controls the on / off state of the switching valve 20 based on the current state of the steering gear. When the steering gear enters a standby state, the control unit can identify and control the switching valve 20, rapidly opening it to establish a direct flow path from the inlet oil line L1 to the main oil line L3. Using the aforementioned control unit improves the system's response speed and accuracy, thereby effectively reducing unnecessary energy loss.

[0045] In one embodiment, such as Figure 1 As shown, the switching valve 20 is a normally open two-position two-way solenoid valve. The normally open design allows the solenoid valve to remain open when de-energized. When the steering gear starts working, the control unit de-energizes the solenoid valve, causing it to close. At this time, hydraulic oil no longer flows into the main oil circuit L3 through the switching valve 20, but instead flows through the priority valve 10, adjusting the hydraulic oil flow according to the steering gear's needs. The normally open solenoid valve features a simple structure and reliable operation, effectively reducing system complexity and failure rate. Furthermore, the normally open design eliminates the need for additional energy to maintain the opening of the switching valve 20 when the steering gear is in standby mode, further saving energy.

[0046] In one embodiment, such as Figure 1 As shown, the priority valve 10 is a hydraulically controlled proportional directional valve. When the steering gear is in operation, the priority valve 10 is used to adjust the flow rate of hydraulic oil from the inlet oil line L1 to the priority outlet and the secondary outlet. A hydraulically controlled proportional directional valve is a key component that can adjust the valve core position according to the proportion of a hydraulic control signal, thereby precisely controlling the flow rate and direction of hydraulic oil. In the embodiments of this invention, the design of the hydraulically controlled proportional directional valve allows it to flexibly adjust the flow rate of hydraulic oil flowing from the inlet oil line L1 into the priority outlet and the secondary outlet according to the needs of the steering gear. This precise control capability not only improves the response speed and accuracy of the hydraulic control system but also helps to reduce system energy loss and improve overall efficiency.

[0047] In one embodiment, the hydraulic proportional directional valve further includes a valve core and a preload member connected to the axial end of the valve core. The preload member applies an axial preload force to the valve core and presses the control port against it, thereby giving the control port a preset opening pressure. The preload member enables the control port to maintain a certain degree of tightness when no external force is applied, thus preventing hydraulic oil leakage and improving the stability and efficiency of the hydraulic control system. When the steering gear pressure feedback port applies pressure to the control port, this pressure needs to overcome the preload force of the preload member to open the control port, thereby adjusting the valve core position of the priority valve 10. This design allows the priority valve 10 to respond more accurately to the steering gear's needs, further reducing energy loss.

[0048] In one embodiment, such as Figure 1 As shown, the hydraulic proportional directional valve has three operating positions. In the first operating position, the inlet and outlet of the priority valve 10 are connected. In the second operating position, the inlet, outlet, and secondary outlet of the priority valve 10 are all connected. In the third operating position, the inlet and outlet of the priority valve 10 are connected. This three-position design allows for flexible adjustment of the hydraulic oil flow direction and volume according to different working states of the steering gear. In the first operating position, the hydraulic oil flows to the steering circuit L2 to meet the steering gear's needs. In the second operating position, the hydraulic oil flows simultaneously to both the steering circuit L2 and the main circuit L3 to accommodate partial steering gear operation. In the third operating position, the hydraulic oil flows to the main circuit L3 to support other hydraulic functions of the working machinery. This design not only improves the flexibility and adaptability of the hydraulic control system but also helps reduce system energy loss and improve overall efficiency.

[0049] In another specific embodiment, when the hydraulically controlled proportional directional valve is in the first operating position, the primary oil outlet, the secondary oil outlet, and the oil inlet of the primary valve 10 are all connected, and the valve opening of the primary oil outlet is greater than the valve opening of the secondary oil outlet; when the hydraulically controlled proportional directional valve is in the second operating position, the primary oil outlet, the secondary oil outlet, and the oil inlet of the primary valve 10 are all connected, and the valve opening of the primary oil outlet is less than the valve opening of the secondary oil outlet.

[0050] In one embodiment, the hydraulic control system further includes a damper 40 connected in the control circuit between the pressure feedback port and the control port. The damper 40 reduces the hydraulic oil flow rate in the control circuit, thereby slowing the movement speed of the priority valve 10 spool. This allows the priority valve 10 to adjust the hydraulic oil flow more smoothly, improving system stability and response speed. The damper 40 design also reduces hydraulic oil shock and vibration, further reducing system energy loss and noise.

[0051] In one embodiment, the hydraulic control system further includes a hydraulic oil tank (not shown) and a safety valve 50. The inlet of the safety valve 50 is connected to the control oil circuit between the pressure feedback port and the control port, and the outlet of the safety valve 50 is connected to the hydraulic oil tank. The safety valve 50 automatically opens when the hydraulic oil pressure between the pressure feedback port and the control port exceeds a preset safety value, releasing excess hydraulic oil to the hydraulic oil tank, thereby preventing system overpressure and protecting the hydraulic control system from damage. The design of the safety valve 50 enhances the safety and reliability of the system, ensuring stable operation of the hydraulic control system under various operating conditions. In a specific embodiment, the safety valve 50 is a relief valve.

[0052] In one embodiment, the hydraulic control system further includes a multi-way valve assembly 30. The inlet of the multi-way valve assembly 30 is connected to the main hydraulic circuit L3, and the working port of the multi-way valve assembly 30 is connected to the hydraulic circuit of the actuator. The multi-way valve assembly 30 can distribute the hydraulic oil in the main hydraulic circuit L3 to different actuators to meet various operational needs of the machine. The design of the multi-way valve assembly 30 allows each actuator to independently obtain the required hydraulic oil flow and pressure, thereby improving the operational flexibility and work efficiency of the machine. In addition, the multi-way valve assembly 30 is compact and easy to operate, which helps to reduce the maintenance cost of the hydraulic control system.

[0053] In one embodiment, a work machine is provided, including the hydraulic control system described above. The work machine includes, but is not limited to, a forklift or a forklift loader.

[0054] In the description of this utility model, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this utility model, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0055] In this utility model, unless otherwise explicitly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0056] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0057] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A hydraulic control system characterized by, include: The fuel supply circuit includes the fuel inlet circuit (L1), the steering circuit (L2), and the main circuit (L3). Priority valve (10), the priority valve (10) has a control port, a priority outlet port connected to the steering oil circuit (L2), a secondary outlet port connected to the main oil circuit (L3) and a priority valve (10) inlet port connected to the inlet oil circuit (L1); The steering gear has an oil inlet connected to the steering oil circuit (L2) and a pressure feedback oil port connected to the control oil port of the priority valve (10). A switching valve (20) is provided in parallel with the priority valve (10). The inlet and outlet of the switching valve (20) are connected to the inlet oil passage (L1) and the main oil passage (L3) respectively. When the steering gear is in standby mode, the switching valve (20) is turned on so that the hydraulic oil entering from the inlet oil passage (L1) flows into the main oil passage (L3) through the switching valve (20).

2. The hydraulic control system of claim 1, wherein, The hydraulic control system also includes: The control unit is electrically connected to both the steering gear and the switching valve (20), and is used to control the switching valve (20) to open or close according to the current state of the steering gear.

3. The hydraulic control system of claim 1, wherein, The switching valve (20) is a normally open two-position two-way solenoid valve.

4. The hydraulic control system of claim 1, wherein, The priority valve (10) is a hydraulically controlled proportional directional valve. When the steering gear is in operation, the priority valve (10) is used to adjust the flow rate of hydraulic oil from the inlet oil passage (L1) to the priority outlet and the secondary outlet.

5. The hydraulic control system of claim 4, wherein, The hydraulic proportional directional valve further includes a valve core and a preload member connected to the axial end of the valve core. The preload member is used to apply an axial preload force to the valve core and press the control port against it so that the control port has a preset opening pressure.

6. The hydraulic control system of claim 4, wherein, The hydraulic proportional directional valve has three working positions. When the hydraulic proportional directional valve is in the first working position, the oil inlet of the priority valve (10) is connected to the priority oil outlet. When the hydraulic proportional directional valve is in the second working position, the oil inlet of the priority valve (10) is connected to both the priority oil outlet and the secondary oil outlet. When the hydraulic proportional directional valve is in the third working position, the oil inlet of the priority valve (10) is connected to the secondary oil outlet.

7. The hydraulic control system according to any one of claims 1 to 6, characterized in that, The hydraulic control system also includes: Damping (40) is connected to the control oil circuit between the pressure feedback oil port and the control oil port.

8. The hydraulic control system according to any one of claims 1 to 6, characterized by, The hydraulic control system also includes: Hydraulic oil tank; Safety valve (50), the oil inlet of the safety valve (50) is connected to the control oil circuit between the pressure feedback oil port and the control oil port, and the oil outlet of the safety valve (50) is connected to the hydraulic oil tank.

9. The hydraulic control system according to any one of claims 1 to 6, characterized by, The hydraulic control system also includes a multi-way valve group (30), the oil inlet of which is connected to the main oil circuit (L3), and the working oil port of which is connected to the actuator oil circuit.

10. A work machine characterized by comprising: Includes a hydraulic control system according to any one of claims 1 to 9.

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