Hydraulic control valve group for vehicle

Abstract

The invention provides a hydraulic control valve group for a vehicle. The hydraulic control valve group for the vehicle comprises a valve body, wherein the valve body is provided with an oil inlet, an oil return port and a lifting working port communicated with the oil inlet; a low-pressure unloading valve is arranged between the oil inlet and the oil return port; and a descending valve is arranged between the lifting working port and the oil return port. The state of the oil inlet path is automatically managed through the low-pressure unloading valve, when the low-pressure unloading valve is communicated with the oil inlet and the oil return port, automatic pressure relief can be achieved in the system starting stage, and impact caused by on-load starting of the power unit is avoided; when the connection between the oil inlet and the oil return port is cut off, the pressure of the main oil way is stably established, and the oil pressure of the lifting working port is gradually increased, so that the load pressure of the carriage is gently overcome, and the stable and impact-free lifting of the carriage is realized; and when the descending valve is communicated with the lifting working port and the oil return port, the compartment can be controllably descended under the action of a load.

Description

Technical Field

[0001] This invention relates to the field of hydraulic control technology, and more specifically, to a hydraulic control valve assembly for vehicles. Background Technology

[0002] The core control component of the hydraulic lifting system for the cargo box of large off-highway vehicles such as mining dump trucks and wide-body trucks is typically a multi-way directional valve. For a long time, the mainstream technology in the industry, both domestically and internationally, has adopted pneumatically or hydraulically pilot-operated multi-way directional valves.

[0003] The working principle of this type of valve assembly is as follows: the pilot valve is driven by an external, independent pilot power source (compressed air or pilot pressure oil), and the control pressure output by the pilot valve pushes the main valve core to switch, thereby realizing the opening and closing and control of the main oil circuit such as lifting, holding, and lowering.

[0004] Although this technical solution has been applied and finalized for many years, it has the following inherent defects: First, the system is complex and relies on an external power source: a complete pilot system (such as an air compressor, air tank, dryer, pilot oil pump, pilot oil circuit, etc.) must be equipped and maintained, which not only increases the complexity of the vehicle layout and space occupation, but also increases the manufacturing cost.

[0005] Secondly, there are more reliability risks: pilot lines, connectors, and pilot air / oil source purification devices are all potential points of failure. Insufficient pilot pressure or contamination can cause the main valve to malfunction, affecting the overall operational reliability of the vehicle.

[0006] Third, energy consumption and efficiency issues: The continuous operation or intermittent start-up of the pilot system (especially the gas supply system) itself consumes energy and there is a risk of leakage, which reduces the overall energy efficiency of the system.

[0007] Fourth, limited environmental adaptability: In low-temperature environments, the pneumatic control system may malfunction due to condensation freezing; the hydraulic pilot system has extremely high requirements for the cleanliness of the hydraulic fluid.

[0008] Therefore, the industry urgently needs a vehicle hydraulic control valve group that can break free from dependence on external pilot power sources, simplify system structure, improve reliability, and adapt to harsh working conditions. Summary of the Invention

[0009] In view of this, the present invention proposes a vehicle hydraulic control valve group, which aims to solve the problems of system complexity, high cost, many failure points and low reliability caused by the existing hydraulic control system of mining trucks having to rely on an external pilot power source (air source or hydraulic source).

[0010] This invention proposes a vehicle hydraulic control valve assembly, which includes a valve body. The valve body has an oil inlet, an oil return port, and a lifting port connected to the oil inlet. A low-pressure unloading valve is provided between the oil inlet and the oil return port to connect or disconnect them. When the oil inlet and the oil return port are connected, pressure is released from the oil inlet. When the oil inlet and the oil return port are disconnected, the oil pressure at the oil inlet gradually increases, thereby gradually overcoming the load pressure of the vehicle body connected to the lifting port, thus lifting the vehicle body. A lowering valve is provided between the lifting port and the oil return port to connect or disconnect them. When the lifting port and the oil return port are connected, the vehicle body lowers.

[0011] Furthermore, in the aforementioned automotive hydraulic control valve assembly, the low-pressure unloading valve includes an unloading inlet connected to the oil inlet and an unloading outlet connected to the oil return port; the low-pressure unloading valve has an unloading connection position connecting the unloading inlet and the unloading outlet, and an unloading disconnect position cutting off the unloading inlet and the unloading outlet.

[0012] Furthermore, in the aforementioned automotive hydraulic control valve assembly, the low-pressure unloading valve further includes a first control port and a second control port. The first control port is connected to the lifting working port, and an unloading return spring is connected to the second control port. The oil pressure at the first control port gradually increases with the oil pressure at the oil inlet and the lifting working port until it exceeds the spring force of the unloading return spring and the oil pressure at the second control port. At this point, the low-pressure unloading valve switches to the unloading connection position, thereby connecting the unloading inlet and the unloading outlet, and thus achieving low-pressure unloading at the oil inlet.

[0013] Furthermore, in the aforementioned vehicle hydraulic control valve group, the second control port is also connected to a lifting control directional valve, which is used to control the oil pressure of the second control port and control the switching of the position of the low-pressure unloading valve.

[0014] Furthermore, in the aforementioned automotive hydraulic control valve assembly, the lifting control directional valve includes a lifting control inlet port connected to the lifting working port, a first working port connected to the second control port, and a second working port connected to the return port; the lifting control directional valve has a first control position and a second control position; when the lifting control directional valve is switched to the first control position, the first working port is connected to the second working port to achieve connection between the second control port of the low-pressure unloading valve and the return port, so that the second control port is in a low-pressure state, thereby controlling the low-pressure unloading valve to switch to the unloading connection position under the action of oil pressure; when the lifting control directional valve is switched to the second control position, the lifting control inlet port is connected to the first working port to achieve connection between the second control port and the lifting working port, so that the first control port and the second control port are under the same pressure, thereby controlling the low-pressure unloading valve to switch to the unloading disconnect position under the action of the unloading reset spring.

[0015] Furthermore, in the aforementioned automotive hydraulic control valve assembly, the lowering valve includes a lowering inlet communicating with the lifting working port and a lowering outlet communicating with the oil return port; the lowering valve has a lowering connection position connecting the lowering inlet and the lowering outlet, and a lowering disconnect position cutting off the lowering inlet and the lowering outlet.

[0016] Furthermore, in the aforementioned automotive hydraulic control valve assembly, the lowering valve further includes a third control port and a fourth control port. The third control port is connected to the lifting working port, and a lowering return spring is connected to the fourth control port. The fourth control port is also connected to a lowering control module, which is used to control the oil pressure at the fourth control port. When the pressure difference between the third control port and the fourth control port is greater than the spring force of the lowering return spring, the lowering valve is controlled to switch to the lowering connection position. When the pressure difference between the third control port and the fourth control port is less than the spring force of the lowering return spring, the lowering valve is controlled to switch to the lowering cut-off position.

[0017] Furthermore, in the aforementioned automotive hydraulic control valve assembly, the descent control module includes: a controllable hydraulic resistance element and a fixed hydraulic resistance element; wherein, the descent valve is disposed on a descent circuit connecting the lifting working port and the return oil port, and a flow control circuit arranged in parallel with the descent circuit is also provided between the lifting working port and the return oil port; the controllable hydraulic resistance element is disposed on the flow control circuit and is used to adjust the effective flow area of ​​the flow control circuit; the fixed hydraulic resistance element is disposed on the flow control circuit and positioned between the controllable hydraulic resistance element and the lifting working port, and is used to provide a basic pressure drop on the flow control circuit; the fourth control port is connected to the oil inlet of the controllable hydraulic resistance element; when the controllable hydraulic resistance element is open, the oil in the lifting working port returns to the return oil port through the fixed hydraulic resistance element and the controllable hydraulic resistance element, and a pressure difference is formed before and after the fixed hydraulic resistance element, so that a pressure difference is formed between the third control port and the fourth control port; when the pressure difference before and after the fixed hydraulic resistance element is greater than the spring force of the descent return spring, the descent valve switches to the descent connection position.

[0018] Furthermore, in the aforementioned automotive hydraulic control valve assembly, the controllable hydraulic resistance element is a flow proportional solenoid valve, and the fixed hydraulic resistance element is a damping element.

[0019] Furthermore, in the aforementioned automotive hydraulic control valve assembly, the low-pressure unloading valve and the lowering valve are integrated side-by-side inside the valve body.

[0020] The vehicle hydraulic control valve group provided by this invention is suitable for the hydraulic system of mining trucks. It automatically manages the oil inlet status through a low-pressure unloading valve: when the valve connects the oil inlet and the return port, automatic pressure relief is achieved during system startup, avoiding the impact of starting the power unit under load; when the valve disconnects the oil inlet and the return port, the main oil circuit pressure is stably established, and the oil pressure at the lifting port gradually increases, thus smoothly overcoming the load pressure of the truck bed and achieving stable, shock-free lifting of the truck bed; the return oil circuit is directly controlled through a lowering valve: when the valve connects the lifting port and the return port, the truck bed achieves controllable lowering under load. This vehicle hydraulic control valve group abandons the complex path of traditional pneumatic or hydraulic pilot control and creatively realizes the core function through the self-adjusting logic of the internal oil circuit of the valve body. This highly integrated design fundamentally solves a series of drawbacks caused by the existing mining truck hydraulic control system's reliance on an external pilot power source (pneumatic or hydraulic source), achieving significant technological progress. Its beneficial effects are specifically reflected in: 1. The system is greatly simplified, highly integrated, and cost-effective: It completely eliminates the need for a separate air source compressor, air tank, pilot oil pump, pilot piping, and corresponding auxiliary devices such as filters and dryers. The valve assembly has a compact structure, with all functions integrated into a single valve body, significantly reducing the number of parts, installation space, and connection points, thereby lowering manufacturing costs and maintenance complexity.

[0021] 2. Significantly improved reliability and durability: By eliminating dependence on pilot pressure stability and pilot medium cleanliness, the failure rate of the valve assembly is greatly reduced. The system's anti-contamination capability is enhanced, making it particularly suitable for long-term reliable operation of mining trucks under harsh conditions such as dust, vibration, and alternating high and low temperatures, reducing the risk of vehicle downtime due to pilot system failure.

[0022] 3. Intelligent soft start and precise pressure management are achieved: The design of the low-pressure unloading valve enables the system to have adaptive pressure relief and pressure build-up capabilities. Automatic unloading protects the power source during startup, and the pressure rises smoothly during lifting, achieving a "soft start" lifting of the cargo box, effectively reducing hydraulic shock and extending the service life of hydraulic components and structural parts.

[0023] 4. Reduced energy consumption and improved energy efficiency: There is no need to provide continuous or intermittent power to the separate pilot system, eliminating the energy consumption and potential leakage loss of the pilot system, and improving the energy utilization efficiency of the whole vehicle.

[0024] 5. Enhanced Environmental Adaptability and Safety: The pure hydraulic main oil circuit control mode avoids the risk of icing in the pneumatic control system at low temperatures and also reduces the stringent requirements for ultra-fine oil filtration. The descent valve, as a control point directly installed on the main oil circuit, has a direct and reliable on / off state, ensuring the controllability and safety of the descent action.

[0025] Furthermore, this vehicle hydraulic control valve assembly relies on the load pressure of the vehicle compartment itself, and changes the form of the oil circuit by switching the solenoid valve on and off to realize the reversal of the valve core, thereby achieving the purpose of various actions. In addition, the valve core of this vehicle hydraulic control valve assembly has a large diameter, strong oil flow capacity, and low pressure loss, which can meet the general needs of the market. Attached Figure Description

[0026] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings: Figure 1 A schematic diagram of a vehicle hydraulic control valve assembly provided in an embodiment of the present invention; Figure 2 A schematic diagram of the low-pressure unloading valve in the vehicle hydraulic control valve group provided in this embodiment of the invention, showing the principle of low-pressure unloading when the inlet and outlet of the valve are connected. Figure 3 A schematic diagram of the vehicle hydraulic control valve group used for lifting the cargo compartment according to an embodiment of the present invention; Figure 4A schematic diagram illustrating the principle of lowering the vehicle compartment when the lowering valve in the vehicle hydraulic control valve group provided in this embodiment of the invention connects the lifting working port and the oil return port; Figure 5 The right view of the automotive hydraulic control valve assembly provided in an embodiment of the present invention; Figure 6 This is a front view of a vehicle hydraulic control valve assembly provided in an embodiment of the present invention; Figure 7 A left view of a vehicle hydraulic control valve assembly provided in an embodiment of the present invention; Figure 8 This is a top view of a vehicle hydraulic control valve assembly provided in an embodiment of the present invention; Figure 9 for Figure 6 Sectional view at point II; Figure 10 for Figure 6 A cross-sectional view at point JJ; Figure 11 for Figure 7 The K-direction view in the middle; Explanation of reference numerals in the attached figures: 1-Valve body, 11-Unloading valve port, 12-Lowering valve port, 2-Low-pressure unloading valve, 21-Unloading valve core, 22-Unloading return spring, 3-Lowering valve, 31-Lowering valve core, 32-Lowering return spring, 4-Lifting control directional valve, 5-Fixed hydraulic resistance element, 6-Controllable hydraulic resistance element, 7-Lifting check valve, 8-Overflow safety valve, 9-Return check valve, 10-Buffer damping, 101-Filter screen, 102-Inlet valve P-Main oil inlet, P1-Secondary oil inlet, mp-Main pressure test port, T-Main return oil port, T1-Secondary return oil port, A-Lifting working port, ma-Lifting pressure test port, Y1-First control port, Y2-Second control port, Y3-Third control port, Y4-Fourth control port, B-Unloading inlet, C-Unloading outlet, D-Lifting inlet, E-First working port, F-Second working port, G-Lowering inlet, H-Lowering outlet. Detailed Implementation

[0027] Exemplary embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided to enable a more thorough understanding of the present disclosure and to fully convey the scope of the disclosure to those skilled in the art. It should be noted that, unless otherwise specified, the embodiments and features described herein can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0028] See Figures 1 to 11The figure illustrates a preferred structure of a vehicle hydraulic control valve assembly provided in an embodiment of the present invention. As shown, the vehicle hydraulic control valve assembly includes: a valve body 1, a low-pressure unloading valve 2, a lowering valve 3, and a lifting control directional valve 4.

[0029] The valve body 1 is provided with an oil inlet, an oil return port, and a lifting working port A connected to the oil inlet.

[0030] Specifically, the valve body 1 can be designed with profiles to accommodate a multi-port layout. The valve body 1 has an inlet, a return port, and a lifting port A, which can connect to the inlet. To prevent oil in the lifting port A from flowing back to the inlet, preferably, a lifting check valve 7 is provided in the connection passage between the lifting port A and the inlet, so that oil in the connection passage can only flow from the inlet to the lifting port A. In this embodiment, there can be two inlets and two return ports: a main inlet P, a secondary inlet P1, a main return port T, and a secondary return port T1. The main inlet P and the secondary inlet P1 are connected and both are connected to a hydraulic pump. The main return port T and the secondary return port T1 are connected and both can be connected to an oil tank. A return check valve 9 can be provided upstream of the secondary return port T1 to prevent backflow of oil from the oil tank. The lifting port A can also be connected to the lifting control oil chamber. When the lifting port A is inserted into the lifting control oil chamber, the lifting cylinder actuates, causing the entire vehicle, especially the cargo box, to lift. The oil in the lifting control oil chamber flows back from the lifting port A to the oil tank, causing the entire vehicle, especially the cargo box, to lower. In this embodiment, the valve body 1 is also provided with a lifting pressure measuring port ma, which is connected to the lifting port A and used to measure the pressure of the lifting port A; the valve body 1 is also provided with a main pressure measuring port mp, which is connected to the oil inlet and used to measure the pressure of the oil inlet. In particular, the main pressure measuring port mp is connected to the main oil inlet P and used to measure the pressure of the main oil inlet P.

[0031] A low-pressure unloading valve 2 is provided between the oil inlet and the oil return port to connect or disconnect the oil inlet and the oil return port. When the oil inlet and the oil return port are connected, the pressure of the oil inlet is relieved. When the oil inlet and the oil return port are disconnected, the oil pressure of the oil inlet gradually increases, thereby enabling the oil pressure of the lifting working port A to gradually overcome the load pressure of the car body connected to the lifting working port A, thus realizing the lifting of the car body.

[0032] Specifically, the oil inlet and outlet are connected via a low-pressure unloading circuit, and a low-pressure unloading valve 2 is provided on the low-pressure unloading circuit for connecting or disconnecting the low-pressure unloading circuit. For example... Figure 2As shown, when the low-pressure unloading valve 2 connects the inlet and outlet, the low-pressure unloading circuit is open. The oil input through the inlet passes through the low-pressure unloading valve 2 and returns to the oil tank through the outlet, thus relieving pressure on the inlet. Both the inlet and the low-pressure unloading circuit are in a low-pressure state. At this time, the oil pressure is less than the load pressure of the truck bed at the lifting port A, so the truck bed will not be lifted. That is, the vehicle hydraulic control valve group has a low-pressure unloading function. Figure 1 As shown, when the low-pressure unloading valve 2 cuts off the oil inlet and return port, the oil from the oil inlet enters the valve body 1 and passes through the lifting check valve 7 to the lifting working port A. Because the low-pressure unloading circuit is blocked, the oil pressure gradually increases, overcoming the load pressure of the truck bed at the lifting working port A, and pushing the cylinder rod to extend out of the lifting truck bed.

[0033] A lowering valve 3 is provided between the lifting port A and the return port to connect or disconnect the lifting port A and the return port. When the lifting port A and the return port are connected, the carriage lowers.

[0034] Specifically, a descent circuit is provided between the lifting port A and the return port. The descent circuit is connected in series with the lifting circuit, and provides oil inlet and outlet for the lifting port A, respectively. In this embodiment, the descent circuit and the lifting circuit form a car body control circuit, which is arranged in parallel with the low-pressure unloading circuit, and the two are independent of each other. A descent valve 3 is provided on the descent circuit for connecting or disconnecting the descent circuit. In particular, during low-pressure unloading and car body lifting, the descent valve 3 can disconnect the descent circuit, and during car body descent, the descent valve 3 can connect the descent circuit, opening the oil passage from the lifting port A to the return port, and the car body descends.

[0035] See also Figures 1 to 4 To ensure the safety of the vehicle's hydraulic control valve assembly, preferably, an overflow circuit connected in parallel with the low-pressure unloading circuit is provided between the oil inlet and the oil return port, and an overflow safety valve 8 is provided on the overflow circuit. Specifically, the overflow circuit is arranged in parallel with the low-pressure unloading circuit between the oil inlet and the oil return port. The pressure inlet of the overflow safety valve 8 is connected to the oil inlet, and the overflow outlet is connected to the oil return port. The pressurized oil at the pressure inlet of the overflow safety valve 8 acts on the valve core (such as a cone valve core or a ball valve core) inside the overflow safety valve 8. When this hydraulic pressure is less than the preload of the adjusting spring on the other side of the valve core of the overflow safety valve 8, the valve is closed, the oil cannot pass through, and the overflow safety valve 8 does not work. When the system pressure increases, especially when it is greater than or equal to the preset lifting pressure, the hydraulic pressure acting on the valve core is greater than the spring preload, the valve core is pushed open, and the oil begins to flow from the pressure inlet to the overflow port. The preset lifting pressure can be 22 MPa.

[0036] See also Figures 1 to 2 The low-pressure unloading valve 2 includes an unloading inlet B connected to the oil inlet and an unloading outlet C connected to the oil return port; the low-pressure unloading valve 2 has the following characteristics: Figure 2The unloading connection point between the unloading inlet B and the unloading outlet C is shown in the figure. Figure 1 The unloading disconnection position is shown at the unloading inlet B and the unloading outlet C.

[0037] Specifically, the low-pressure unloading valve 2 includes an unloading inlet B and an unloading outlet C, which are respectively connected to the main oil inlet P and the main oil return port T. The low-pressure unloading valve 2 has an unloading connection position connecting the unloading inlet B and the unloading outlet C, and an unloading disconnect position cutting off the connection between the unloading inlet B and the unloading outlet C, thus realizing the disconnection and connection of the low-pressure unloading circuit. In this embodiment, the low-pressure unloading valve 2 can be a three-position two-way structure, which can adopt a large diameter, has strong oil flow capacity, and reduces pressure loss. The low-pressure unloading valve 2 can be embedded inside the valve body 1, that is, as... Figure 10 As shown, along its length direction (e.g.) of valve body 1 Figure 10 The unloading valve hole 11 is provided in the horizontal direction shown. The unloading valve core 21 of the low-pressure unloading valve 2 is along the length direction of the unloading valve hole 11 (e.g., in the horizontal direction shown). Figure 10 The unloading valve core 21 (shown horizontally) is slidably disposed within the unloading valve orifice 11, forming a low-pressure unloading valve 2 in conjunction with the unloading valve orifice 11. The unloading inlet B and unloading outlet C are respectively disposed at different positions within the unloading valve orifice 11, particularly on the right and left sides. The movement of the unloading valve core 21 enables the connection and disconnection of the unloading inlet B and the unloading outlet C, as shown. Figure 10 As shown, the unloading valve core 21 cuts off the unloading inlet B and the unloading outlet C. In this embodiment, as... Figure 1 As shown, the low-pressure unloading valve 2 is connected to a lifting control directional valve 4, which is used to control the switching of the position of the low-pressure unloading valve 2, that is, the switching between the unloading connected position and the unloading disconnected position. Among them, the lifting control directional valve 4 is a solenoid directional valve, so as to realize the switching of the position of the low-pressure unloading valve 2 through electrical control, thereby realizing the control of the lifting function.

[0038] See also Figure 1 , Figure 2 , Figure 10 The low-pressure unloading valve 2 also includes a first control port Y1 and a second control port Y2. The first control port Y1 is connected to the lifting working port A, and the second control port Y2 is connected to an unloading return spring 22. As the oil pressure at the oil inlet and the lifting working port A gradually increases, the oil pressure at the first control port Y1 also gradually increases until it exceeds the spring force of the unloading return spring 22 and the oil pressure at the second control port Y2. At this point, the low-pressure unloading valve 2 switches to the unloading connection position, realizing the connection between the unloading inlet B and the unloading outlet C, thereby realizing the low-pressure unloading of the oil inlet.

[0039] Specifically, the unloading valve hole 11 is a through hole extending along the length of the valve body 1, with plugs at both ends for sealing. The left and right ends of the unloading valve core 21 form two control cavities with the plugs on the left and right sides, respectively, namely the first control port Y1 and the second control port Y2. In this embodiment, the first control port Y1 can be connected to the lifting working port A through an internal passage, such as... Figure 10 As shown, the first control port Y1 is connected to the lifting pressure measuring port ma on the valve body 1 through the internal passage of the valve core. A load-bearing return spring 22 can be provided at the second control port Y2, especially between the right side plug and the right end of the unloading valve core 21, as shown. Figure 10 As shown, in the initial position, the low-pressure unloading valve 2 is in the unloading cut-off position under the action of the unloading return spring 22, and oil is input into the oil inlet. As the oil pressure at the oil inlet and the lifting working port A gradually increases, the oil pressure at the first control port Y1 also gradually increases until it exceeds the spring force of the unloading return spring 22 and the oil pressure at the second control port Y2. At this point, the unloading valve core 21 moves to the right under the action of the oil pressure, sliding to the unloading connection position where the unloading inlet B and the unloading outlet C are connected, i.e., the right position, thus realizing low-pressure unloading at the oil inlet. The spring force of the unloading return spring 22 can be 0.22~0.41MPa. In this embodiment, as... Figure 1 As shown, the first control port Y1 side of the low-pressure unloading valve 2, i.e. the non-spring end, may be provided with a buffer damper 10 for buffering the unloading valve core 21.

[0040] See also Figure 1 and Figure 2To achieve the lifting function of the carriage, i.e., the lifting working port A and the main oil inlet P can reach high pressure, preferably, the second control port Y2 is also connected to a lifting control reversing valve 4, which is used to control the oil pressure of the second control port Y2. Then, by reducing the pressure of the second control port Y2, in conjunction with the increase of the pressure of the first control port Y1, when the pressure difference between the first control port Y1 and the second control port Y2 is greater than the spring force of the unloading return spring 22, the unloading valve core 21 switches to the unloading connection position, thereby realizing the low-pressure unloading function. Alternatively, by increasing the pressure of the second control port Y2, in conjunction with the spring force of the unloading return spring 22, until it is greater than the oil pressure of the first control port Y1, the unloading valve core 21 switches to the unloading cut-off position, thereby realizing the lifting function of the carriage. Specifically, the lifting control directional valve 4 is used to control the oil pressure of the second control port Y2 to a low pressure. In particular, it can connect the second control port Y2 to the return port, allowing the unloading valve core 21 to overcome the spring force of the unloading return spring 22 under the oil pressure of the first control port Y1, thus achieving unloading at a low pressure. The lifting control directional valve 4 is also used to control the oil pressure of the second control port Y2 to a high pressure. For example, it can connect the second control port Y2 to the lifting working port A, so that the oil pressure of the first control port Y1 and the second lifting control port are the same. This allows the unloading valve core 21 to slide to the left under the spring force of the unloading return spring 22, returning to the unloading cut-off position that cuts off the unloading inlet B and the unloading outlet C, i.e., the left position. The lifting control directional valve 4 can be a solenoid directional valve, which controls the oil pressure of the second control port Y2 through an electromagnetic signal, thereby switching the position of the low-pressure unloading valve 2.

[0041] See also Figure 1 and Figure 2 The lifting control directional valve 4 includes a lifting control oil inlet connected to the lifting working port A, a first working port E connected to the second control port Y2, and a second working port F connected to the return oil port. The lifting control directional valve 4 has a first control position and a second control position. When the lifting control directional valve 4 is switched to the first control position, the first working port E is connected to the second working port F to realize the connection between the second control port Y2 of the low-pressure unloading valve 2 and the return oil port, so that the second control port Y2 is in a low-pressure state, thereby controlling the low-pressure unloading valve 2 to switch to the unloading connection position under the action of oil pressure. When the lifting control directional valve 4 is switched to the second control position, the lifting control oil inlet is connected to the first working port E to realize the connection between the second control port Y2 and the lifting working port A, so that the first control port Y1 and the second control port Y2 are under the same pressure, thereby controlling the low-pressure unloading valve 2 to switch to the unloading disconnect position under the action of the spring force of the unloading reset spring 22.

[0042] Specifically, the second working port F can be connected to the secondary return port T1. The lifting control directional valve 4 is a solenoid directional valve; when a lifting operation is required, the lifting control directional valve 4 can be energized, such as... Figure 3As shown, the lifting control directional valve 4 is then switched to the second control position, connecting the lifting control oil inlet to the first working port E. Since the lifting control oil inlet is connected to the lifting working port A, and the first working port E is connected to the second control port Y2, which is connected to the spring chamber of the low-pressure unloading valve 2, the spring chamber of the low-pressure unloading valve 2 is connected to the lifting working port A. This means the oil pressure at both ends of the unloading valve core 21 is equal. Under the action of the unloading reset spring 22, the unloading valve core 21 moves to the non-spring side, switching to the unloading disconnect position. This disconnects the low-pressure unloading oil circuit from the main oil inlet P to the main oil return port T, allowing the main oil inlet P to continuously increase pressure, overcoming the load on the lifting working port A and achieving the lifting function. When the lifting action needs to be stopped, the solenoid directional valve is de-energized, as shown... Figure 2 As shown, when the lifting control directional valve 4 is switched to the first control position, the first working port E is connected to the second working port F. The first working port E is connected to the second control port Y2, which is connected to the spring cavity of the low-pressure unloading valve 2. The second working port F is connected to the secondary return port T1. That is to say, when the lifting control directional valve 4 is switched to the first control position, the spring cavity of the low-pressure unloading valve 2 is connected to the secondary return port T1, which can unload the spring cavity of the low-pressure unloading valve 2, that is, the oil in the spring cavity of the low-pressure unloading valve 2 is depressurized. Under the load pressure of the first control port Y1, i.e., the lifting working port A, the unloading valve core 21 overcomes the spring force of the unloading reset spring 22 and moves to the spring side, switching to the unloading connection position, so that the low-pressure unloading oil circuit from the main oil inlet P to the main return port T is connected. The oil in the main oil inlet P is re-unloaded, and the oil in the lifting working port A is kept non-flowing under the action of the lifting check valve 7, ensuring that the car body will not fall. In this embodiment, a filter screen 101 may be provided on the passage connecting the lifting control oil inlet and the lifting working port A.

[0043] See also Figure 1 , Figure 4 and Figure 10 The lowering valve 3 includes a lowering inlet G connected to the lifting working port A and a lowering outlet H connected to the return oil port; the lowering valve 3 has the following characteristics: Figure 4 The descending connection points shown are the descending inlet G and the descending outlet H, as follows: Figure 1 The diagram shows the disconnection point between the descent inlet G and the descent outlet H.

[0044] Specifically, the lowering valve 3 includes a lowering inlet G and a lowering outlet H, which are connected to the lifting working port A and the main return port T, respectively. The lowering valve 3 has the following characteristics: Figure 4 The descending connection points shown are the descending inlet G and the descending outlet H, as follows: Figure 1 The disconnect position shown, which cuts off the descent inlet G and the descent outlet H, can realize the disconnection and connection of the descent circuit.

[0045] In this embodiment, the downcomer valve 3 can be a three-position two-way structure, with a large diameter, strong oil flow capacity, and reduced pressure loss. The downcomer valve 3 can be embedded inside the valve body 1, that is, as... Figure 10 As shown, along its length direction (e.g.) of valve body 1 Figure 10 A descending valve 3 hole 12 is provided in the horizontal direction shown. The descending valve core 31 of the descending valve 3 is along the length direction of the descending valve 3 hole 12 (e.g., in the horizontal direction shown). Figure 10 The valve core 31 (shown horizontally) is slidably disposed within the orifice 12 of the downcomer valve 3, forming the downcomer valve 3. In other words, the low-pressure unloading valve 2 and the downcomer valve 3 are integrated side-by-side inside the valve body 1. The downcomer inlet G and the downcomer outlet H are respectively located at different positions on the orifice 12 of the downcomer valve 3, especially on the left and right sides. The movement of the downcomer valve core 31 enables the connection and disconnection of the downcomer inlet G and the downcomer outlet H, as shown. Figure 10 As shown, the descent valve core 31 cuts off the descent inlet G and the descent outlet H. In this embodiment, the descent outlet H can be located directly below the unloading outlet C, and the two can be connected through a circuit inside the valve body 1, and also connected to the main return port T through the internal circuit of the valve body 1. In this embodiment, the descent valve 3 is connected to a descent control module, which is used to control the descent valve 3 to switch positions, that is, to switch between the descent connected position and the descent disconnected position.

[0046] See also Figure 1 , Figure 4 and Figure 10 The lowering valve 3 also includes a third control port Y3 and a fourth control port Y4. The third control port Y3 is connected to the lifting working port A, and the fourth control port Y4 is connected to a lowering return spring 32. The fourth control port Y4 is also connected to a lowering control module, which is used to control the oil pressure of the fourth control port Y4. When the pressure difference between the third control port Y3 and the fourth control port Y4 is greater than the spring force of the lowering return spring 32, the lowering valve 3 is controlled to switch to the lowering connection position. When the pressure difference between the third control port Y3 and the fourth control port Y4 is less than the spring force of the lowering return spring 32, the lowering valve 3 is controlled to switch to the lowering cut-off position.

[0047] Specifically, the lowering valve 3 hole 12 is a through hole extending through the length of the valve body 1, with plugs at both ends for sealing. The left and right ends of the lowering valve core 31 form two control chambers with the plugs on the left and right sides, respectively, namely the third control port Y3 and the fourth control port Y4. In this embodiment, the third control port Y3 can be connected to the lifting working port A through an internal passage, such as... Figure 10 As shown, the third control port Y3 is connected to the lifting pressure testing port ma on the valve body 1 through the internal passage of the valve core, that is, it is connected to the lifting working port A through the lifting pressure testing port ma. A lowering return spring 32 can be provided at the fourth control port Y4, especially between the right side plug and the right end of the lowering valve core 31, such as... Figure 10 As shown, in the initial position, the lowering valve 3 is in the lowering cut-off position under the action of the lowering return spring 32, and oil is input through the oil inlet. As the oil pressure at the oil inlet and the lifting working port A gradually increases, the oil pressure at the third control port Y3 also gradually increases until it exceeds the spring force of the lowering return spring 32 and the oil pressure at the fourth control port Y4. At this point, the lowering valve core 31 moves to the right under the action of the oil pressure, sliding to the lowering connection position (right position) where the unloading inlet B and the unloading outlet C are connected, thus realizing the lowering of the carriage. The spring force of the unloading return spring 22 can be 0.29~0.68MPa. In this embodiment, as... Figure 1 As shown, the third control port Y3 side of the lowering valve 3, i.e. the non-spring end, may be provided with a buffer damper 10 for buffering the lowering valve core 31.

[0048] In this embodiment, to ensure that the lowering valve 3 can be in the lowering cut-off position when the lifting working port A is under high pressure, preferably, the fourth control port Y4 can be connected to a lowering control module to control the oil pressure of the fourth control port Y4. When the pressure difference between the third control port Y3 and the fourth control port Y4 is greater than the spring force of the lowering return spring 32, the lowering valve 3 is controlled to switch to the lowering connection position. When the pressure difference between the third control port Y3 and the fourth control port Y4 is less than the spring force of the lowering return spring 32, the lowering valve 3 is controlled to switch to the lowering cut-off position.

[0049] Specifically, the descent control module can control the oil pressure at the fourth control port Y4. It can reduce the pressure at the fourth control port Y4, and when the pressure at the third control port Y3 increases, the pressure difference between the third control port Y3 and the fourth control port Y4 is greater than the spring force of the descent return spring 32. At this point, the descent valve core 31 switches to the descent connection position, thereby realizing the descent function of the carriage. Alternatively, it can reduce the pressure by increasing the relative pressure at the fourth control port Y4, for example, and restore the pressure to the original pressure. When the spring force of the descent return spring 32 is greater than the oil pressure at the third control port Y3, the descent valve core 31 switches to the unloading cut-off position, thereby realizing the lifting function of the carriage. The descent control module controls the oil pressure of the fourth control port Y4 to a low pressure. In particular, it can connect the fourth control port Y4 to the return oil port or a low oil pressure connection point connected to the return oil port. This allows the descent valve core 31 to overcome the spring force of the descent reset spring 32 under the pressure difference between the third control port Y3 and the fourth control port Y4, and move to the right to the descent connection position, thereby realizing the descent of the carriage. The descent control module also controls the oil pressure of the fourth control port Y4 to a high pressure. For example, it can adjust the point connected to the fourth control port Y4 to the oil pressure of the lifting working port A, so that the oil pressure of the third control port Y3 and the fourth control port Y4 are the same. This allows the descent valve core 31 to slide to the left under the spring force of the descent reset spring 32, and reset to the descent cut-off position, i.e., the left position, which cuts off the descent inlet G and the descent outlet H.

[0050] See also Figure 1and Figure 4 The descent control module includes a controllable hydraulic resistance element 6 and a fixed hydraulic resistance element 5. A descent valve 3 is installed on the descent circuit connecting the lifting working port A and the return port. A flow control circuit is also provided between the lifting working port A and the return port, arranged in parallel with the descent circuit. The controllable hydraulic resistance element 6 is installed on the flow control circuit to adjust the effective flow area of ​​the flow control circuit. The fixed hydraulic resistance element 5 is installed on the flow control circuit and positioned between the controllable hydraulic resistance element 6 and the lifting working port A to provide a base pressure drop on the flow control circuit. The fourth control port Y4 is connected to the inlet of the controllable hydraulic resistance element 6. When the controllable hydraulic resistance element 6 is open, the oil in the lifting working port A returns to the return port through the fixed hydraulic resistance element 5 and the controllable hydraulic resistance element 6. A pressure difference is formed before and after the fixed hydraulic resistance element 5, so that a pressure difference is formed between the third control port Y3 and the fourth control port Y4. When the pressure difference before and after the fixed hydraulic resistance element 5 is greater than the spring force of the descent reset spring 32, the descent valve 3 switches to the descent connection position.

[0051] Specifically, the flow control loop connects the secondary return port T1 and the lifting working port A to control the differential pressure in segments. The fixed hydraulic resistance element 5 and the controllable hydraulic resistance element 6 are arranged sequentially along the oil flow direction, with the fixed hydraulic resistance element 5 upstream and the controllable hydraulic resistance element 6 downstream. When the controllable hydraulic resistance element 6 is open, the oil in the lifting working port A flows sequentially through the fixed hydraulic resistance element 5 and the controllable hydraulic resistance element 6 to the secondary return port T1. In other words, the fixed hydraulic resistance element 5 provides the base pressure drop, and the controllable hydraulic resistance element 6 regulates the oil flow rate, controlling the pressure difference before and after the fixed hydraulic resistance element 5. This, in turn, controls the pressure difference between the two control ports at both ends of the lowering valve core 31, controlling the switching of the lowering valve core 31's position and the descent speed of the carriage. The descent speed of the carriage decreases as the resistance of the controllable hydraulic resistance element 6 increases. In this embodiment, the controllable hydraulic resistance element 6 is a flow-proportional solenoid valve, which controls the oil pressure at the fourth control port Y4 via an electromagnetic signal, thereby switching the position of the lowering valve 3 and controlling the descent speed of the carriage. The fixed hydraulic resistance element 5 is a damping element, so that when the controllable hydraulic resistance element 6 is open, there is a pressure difference between the two control ports at both ends of the lowering valve core 31. In particular, the larger the current of the flow-proportional solenoid valve, the smaller the resistance, and the smaller the total resistance in the flow control circuit, resulting in an increase in the flow rate in the flow control circuit. Therefore, the flow rate of the fixed hydraulic resistance element 5 increases accordingly, which not only increases the descent speed of the carriage but also increases the pressure difference across the fixed hydraulic resistance element 5, thereby increasing the pressure difference between the two control ports at both ends of the lowering valve core 31. Thus, by adjusting the current of the flow-proportional solenoid valve, the position switching of the lowering valve 3 can be controlled, and the descent speed can also be controlled. In this embodiment, a filter screen 101 can be provided at the outlet of the fixed hydraulic resistance element 5.

[0052] To prevent hydraulic oil from flowing back from the low-pressure unloading valve 2 to the inlet and pump when the lowering valve 3 is in the lowering connected position, such as... Figure 4 As shown, preferably, an oil inlet check valve 102 can be provided at the oil inlet so that oil can only flow out of the pump and into the valve group from the oil inlet, and cannot flow back into the pump.

[0053] In this embodiment, the vehicle hydraulic control valve group is an electronically controlled valve group and is an integral valve group, with each component installed on the valve body 1 or embedded inside the valve body 1.

[0054] This vehicle-mounted hydraulic control valve assembly is suitable for the hydraulic control system of electrically controlled mining trucks. Its working principle is as follows: When there is no oil or electricity, if the truck body is on the frame, the main oil inlet P and the secondary oil inlet P1 will not receive oil, and the lifting port A will have no pressure. The principle and location of each component of the vehicle hydraulic control valve group are as follows: Figure 1 As shown.

[0055] If the carriage is in the raised or partially raised position, there is pressure at the lifting port A. Regardless of whether the main oil inlet P is open, the oil pushes the unloading valve core 21 towards the spring side because the pressure at the first control port Y1 is greater than the spring force of the unloading return spring 22, causing the low-pressure unloading valve 2 to be in the spring position. Figure 2 The unloading connection shown connects the main oil inlet P to the main oil return port T, discharging the oil input from the inlet, especially the oil input from the secondary inlet, such as the steering module.

[0056] Neutral position (oil supply, no power supply): The oil enters the valve body 1 through the main inlet P and the secondary inlet P1, passes through the lifting check valve 7, and then to the lifting working port A and the buffer damper 10 upstream of the low-pressure unloading valve 2, respectively, to the left end of the unloading valve core 21, i.e., the first control port Y1. Because the low-pressure unloading valve 2 is in the unloading cut-off position, i.e., the oil circuit is blocked, the oil pressure gradually increases. When the oil pressure gradually increases to a level greater than the spring force of the unloading return spring 22, the oil pushes the unloading valve core 21 to move towards the spring side (e.g., ...). Figure 10 As shown (to the right), the oil in the chamber where the unloading return spring 22 is located, i.e., the oil in the second control port Y2, passes through the oil circuit (the oil circuit connecting the first working port E and the second working port F in the lifting control reversing valve 4) and the return oil check valve 9 to the secondary return oil port T1. As the unloading valve core 21 moves, the unloading inlet B and the unloading outlet C gradually connect, and the oil circuit from the inlet to the main return oil port T gradually opens, thus enabling the low-pressure unloading valve 2 to automatically... Figure 1 Turn to Figure 2 At the unloading connection position, the oil input from the main oil inlet P and the secondary oil inlet P1 passes through the unloading valve core 21 to the main return oil port T, returning to the oil tank. At this time, the oil pressure is less than the load of the lifting working port A, so the car body will not be lifted.

[0057] Lifting function (oil supply, lifting control directional valve 4 is energized, controllable hydraulic resistance element 6 is de-energized): After the lifting control directional valve 4 is energized, its position changes from... Figure 1 The initial first control bit is converted to Figure 3 The second control position in the system, the oil circuit changes as follows Figure 3 As shown, the first working port E is disconnected from the second working port F, thus disconnecting the chamber containing the unloading return spring 22 (i.e., the second control port Y2) from the secondary return port T1. Simultaneously, the lifting inlet port D connects to the first working port E, meaning the chamber containing the unloading return spring 22 (i.e., the second control port Y2) connects to the lifting working port A. The other end of the unloading valve core 21 (i.e., the first control port Y1) remains connected to the lifting working port A. Therefore, the oil pressure at both ends of the unloading valve core 21 is the same, and the unloading valve core 21 moves under the action of the unloading return spring 22 (e.g., ...). Figure 10 (as shown by the leftward movement), so that the low-pressure unloading valve 2 can move from... Figure 2 The unloading connection position is converted to Figure 3 The unloading cut-off position isolates the unloading inlet B from the unloading outlet C. The oil passage from the main inlet P to the main return port T is... Figure 2 During the unloading of the middle section, the phase state changes into Figure 3 In the isolated state, the oil pressure of the oil entering through the main oil inlet P gradually increases, overcoming the load pressure of the lifting working port A, and pushing the cylinder rod to extend out of the lifting compartment.

[0058] Lowering function (oil supply, lifting control directional valve 4 de-energized, controllable hydraulic resistance element 6 energized): After the controllable liquid resistance element 6 is energized, its position changes from Figure 1 The initial cut position is converted to Figure 4 The connection points in the middle, the changes in the oil circuit are as follows Figure 4 As shown, the lifting working port A and the chamber containing the lowering return spring 32, i.e., the fourth control port Y4, are connected to the secondary return port T1. The oil at the lifting working port A first flows through the fixed hydraulic resistance element 5 to the secondary return port T1. The pressure loss generated during the flow through the fixed hydraulic resistance element 5 means that the oil pressure at the lifting working port A is greater than the oil pressure after the fixed hydraulic resistance element 5. At this time, the chamber containing the lowering return spring 32, i.e., the fourth working port, is connected to the fixed hydraulic resistance element 5, and the oil pressures at both locations are the same. The other end of the lowering valve core 31, i.e., the third control port Y3, has the same oil pressure as the lifting working port A. As the energizing current of the flow proportional solenoid valve increases, more oil flows through, and the pressure difference between the two ends of the lowering valve core 31 becomes larger. When the difference exceeds the spring force of the lowering return spring 32, the lowering valve core 31 moves (e.g., ...). Figure 10 As shown (moving to the right), the descent inlet G and descent outlet H gradually connect, the oil circuit from the lifting working port A to the main return oil port T gradually opens, and the descent speed of the carriage gradually increases. During this process, the low-pressure unloading valve 2 is in... Figure 4 As shown in the unloading connection position, the oil input through the oil inlet passes through the unloading valve core 21 to the main return oil port T and returns to the oil tank.

[0059] In summary, the vehicle-mounted hydraulic control valve group provided in this embodiment is suitable for the hydraulic system of mining trucks. It automatically manages the oil inlet status through the low-pressure unloading valve 2: when connected to the inlet and outlet, automatic pressure relief is achieved during system startup, avoiding the impact of starting the power unit under load; when disconnected from the inlet and outlet, the main oil circuit pressure is stably established, and the oil pressure at the lifting port A gradually increases, thus smoothly overcoming the load pressure of the truck bed and achieving stable, shock-free lifting of the truck bed; the return oil circuit is directly controlled through the lowering valve 3: when connected to the lifting port A and the return port, the truck bed achieves controllable lowering under load. This vehicle-mounted hydraulic control valve group abandons the complex path of traditional pneumatic or hydraulic pilot control and creatively realizes the core function through the self-adjusting logic of the internal oil circuit of the valve body 1. This highly integrated design fundamentally solves a series of drawbacks caused by the existing mining truck hydraulic control system's reliance on an external pilot power source (pneumatic or hydraulic source), achieving significant technological progress. Its beneficial effects are specifically reflected in: 1. The system is greatly simplified, highly integrated, and cost-effective: It completely eliminates the need for a separate air source compressor, air tank, pilot oil pump, pilot piping, and corresponding auxiliary devices such as filters and dryers. The valve assembly has a compact structure, with all functions integrated into a single valve body 1, significantly reducing the number of parts, installation space, and connection points, thereby lowering manufacturing costs and maintenance complexity.

[0060] 2. Significantly improved reliability and durability: By eliminating dependence on pilot pressure stability and pilot medium cleanliness, the failure rate of the valve assembly is greatly reduced. The system's anti-contamination capability is enhanced, making it particularly suitable for long-term reliable operation of mining trucks under harsh conditions such as dust, vibration, and alternating high and low temperatures, reducing the risk of vehicle downtime due to pilot system failure.

[0061] 3. Intelligent soft start and precise pressure management are achieved: The design of the low-pressure unloading valve 2 enables the system to have adaptive pressure relief and pressure build-up capabilities. Automatic unloading protects the power source during startup, and the pressure rises smoothly during lifting, achieving a "soft start" lifting of the carriage, effectively reducing hydraulic shock and extending the service life of hydraulic components and structural parts.

[0062] 4. Reduced energy consumption and improved energy efficiency: There is no need to provide continuous or intermittent power to the separate pilot system, eliminating the energy consumption and potential leakage loss of the pilot system, and improving the energy utilization efficiency of the whole vehicle.

[0063] 5. Enhanced Environmental Adaptability and Safety: The pure hydraulic main oil circuit control mode avoids the risk of icing in the pneumatic control system at low temperatures and also reduces the stringent requirements for ultra-fine oil filtration. The descending valve 3, as a control point directly installed on the main oil circuit, has a direct and reliable on / off state, ensuring the controllability and safety of the descending action.

[0064] Furthermore, this vehicle hydraulic control valve assembly relies on the load pressure of the vehicle compartment itself, and changes the form of the oil circuit by switching the solenoid valve on and off to realize the reversal of the valve core, thereby achieving the purpose of various actions. In addition, the valve core of this vehicle hydraulic control valve assembly has a large diameter, strong oil flow capacity, and low pressure loss, which can meet the general needs of the market.

[0065] It should be noted that in the description of this invention, the terms "upper", "lower", "left", "right", "inner", "outer", etc., which indicate directions or positional relationships, are based on the directions or positional relationships shown in the accompanying drawings. This is only for the convenience of description and is not intended to indicate or imply that the device or element must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation of this invention.

[0066] Furthermore, it should be noted that, in the description of this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0067] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A vehicle hydraulic control valve assembly, characterized in that, include: Valve body; wherein, The valve body is provided with an oil inlet, an oil return port, and a lifting working port connected to the oil inlet; A low-pressure unloading valve is provided between the oil inlet and the oil return port to connect or disconnect the oil inlet and the oil return port. When the oil inlet and the oil return port are connected, the pressure of the oil inlet is relieved. When the oil inlet and the oil return port are disconnected, the oil pressure of the oil inlet gradually increases, thereby enabling the oil pressure of the lifting working port to gradually overcome the load pressure of the car body connected to the lifting working port, thus realizing the lifting of the car body. A lowering valve is provided between the lifting port and the return port to connect or disconnect the lifting port and the return port. When the lifting port and the return port are connected, the carriage lowers.

2. The automotive hydraulic control valve assembly according to claim 1, characterized in that, The low-pressure unloading valve includes an unloading inlet connected to the oil inlet and an unloading outlet connected to the oil return port. The low-pressure unloading valve has an unloading connection position that connects the unloading inlet and the unloading outlet, and an unloading disconnect position that disconnects the unloading inlet and the unloading outlet.

3. The automotive hydraulic control valve assembly according to claim 2, characterized in that, The low-pressure unloading valve also includes a first control port and a second control port. The first control port is connected to the lifting working port, and the second control port is connected to an unloading reset spring. The oil pressure at the first control port gradually increases with the oil pressure at the oil inlet and the lifting working port until it exceeds the spring force of the unloading reset spring and the oil pressure at the second control port. At this point, the low-pressure unloading valve switches to the unloading connection position, thereby connecting the unloading inlet and the unloading outlet, and thus achieving low-pressure unloading at the oil inlet.

4. The automotive hydraulic control valve assembly according to claim 3, characterized in that, The second control port is also connected to a lifting control directional valve, which is used to control the oil pressure of the second control port and control the switching of the position of the low-pressure unloading valve.

5. The automotive hydraulic control valve assembly according to claim 4, characterized in that, The lifting control directional valve includes a lifting control oil inlet connected to the lifting working port, a first working port connected to the second control port, and a second working port connected to the return oil port. The lifting control directional valve has a first control position and a second control position; When the lifting control reversing valve is switched to the first control position, the first working port is connected to the second working port to realize the connection between the second control port of the low-pressure unloading valve and the oil return port, so that the second control port is in a low-pressure state, thereby controlling the low-pressure unloading valve to switch to the unloading connection position under the action of oil pressure. When the lifting control reversing valve switches to the second control position, the lifting control oil inlet is connected to the first working port to realize the connection between the second control port and the lifting working port, so that the first control port and the second control port are under the same pressure, thereby controlling the low-pressure unloading valve to switch to the unloading disconnect position under the spring force of the unloading reset spring.

6. The automotive hydraulic control valve assembly according to any one of claims 1 to 5, characterized in that, The lowering valve includes a lowering inlet connected to the lifting working port and a lowering outlet connected to the oil return port; The descending valve has a descending connection position that connects the descending inlet and the descending outlet, and a descending disconnect position that disconnects the descending inlet and the descending outlet.

7. The automotive hydraulic control valve assembly according to claim 6, characterized in that, The lowering valve also includes a third control port and a fourth control port. The third control port is connected to the lifting working port, and a lowering return spring is connected to the fourth control port. The fourth control port is also connected to a descent control module, which is used to control the oil pressure of the fourth control port. When the pressure difference between the third control port and the fourth control port is greater than the spring force of the descent reset spring, the descent valve is controlled to switch to the descent connection position. When the pressure difference between the third control port and the fourth control port is less than the spring force of the descent reset spring, the descent valve is controlled to switch to the descent cut-off position.

8. The automotive hydraulic control valve assembly according to claim 7, characterized in that, The descent control module includes: a controllable liquid resistance element and a fixed liquid resistance element; wherein... The lowering valve is installed on the lowering circuit that connects the lifting working port and the return oil port. A flow control circuit is also provided between the lifting working port and the return oil port and arranged in parallel with the lowering circuit. The controllable liquid resistance element is disposed on the flow control loop to adjust the effective flow area of ​​the flow control loop. The fixed liquid resistance element is disposed on the flow control loop and placed between the controllable liquid resistance element and the lifting working port to provide a base pressure drop on the flow control loop. The fourth control port is connected to the oil inlet of the controllable hydraulic resistance element. When the controllable hydraulic resistance element is open, the oil in the lifting working port returns to the return port through the fixed hydraulic resistance element and the controllable hydraulic resistance element. A pressure difference is formed before and after the fixed hydraulic resistance element, so that a pressure difference is formed between the third control port and the fourth control port. When the pressure difference before and after the fixed hydraulic resistance element is greater than the spring force of the descent reset spring, the descent valve switches to the descent connection position.

9. The automotive hydraulic control valve assembly according to claim 8, characterized in that, The controllable liquid resistance element is a flow proportional solenoid valve, and the fixed liquid resistance element is a damping element.

10. The automotive hydraulic control valve assembly according to any one of claims 1 to 6, characterized in that, The low-pressure unloading valve and the downcomer valve are integrated side-by-side inside the valve body.

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