Vehicle hydraulic steering system and dump truck

Abstract

A kind of vehicle hydraulic steering system, including steering cylinder, steering gear, priority valve, active variable plunger pump, engine, oil tank and controller, the steering cylinder is connected with the steering gear, the steering gear is connected with the priority valve, the priority valve is connected with the active variable plunger pump, the engine is connected with the active variable plunger pump, the oil tank is connected with the steering gear, the priority valve, the active variable plunger pump respectively, the controller is connected with the engine, the active variable plunger pump respectively, the controller exports control current to the active variable plunger pump according to the engine speed, to make the active variable plunger pump output constant oil liquid.The vehicle hydraulic steering system of the utility model can reduce matching loss, and also can guarantee the consistency of steering performance under different working conditions of vehicle.This application also relates to a self-unloading vehicle.

Description

Technical Field

[0001] This utility model relates to the field of hydraulic system technology, and in particular to a vehicle hydraulic steering system and a dump truck. Background Technology

[0002] With the rapid development of industrial technology, the application of hydraulic steering systems is becoming more and more widespread, and the energy efficiency of hydraulic steering systems is receiving increasing attention. Research on energy-saving technologies for hydraulic steering systems is of great significance for the energy efficiency of hydraulic steering systems in wide-body dump trucks.

[0003] For hydraulic steering systems in wide-body dump trucks, designers have traditionally designed systems based on their maximum load. This often results in the hydraulic steering system's output power not being precisely matched to the load, leading to a supply-demand imbalance under low-load conditions and wasting significant energy. Furthermore, the pump's flow rate varies at different engine speeds, making it impossible to guarantee consistent steering performance under different operating conditions. Utility Model Content

[0004] In view of this, the present invention provides a vehicle hydraulic steering system that can reduce matching losses and ensure the consistency of steering performance under different operating conditions.

[0005] A vehicle hydraulic steering system includes a steering cylinder, a steering gear, a priority valve, an active variable displacement piston pump, an engine, a fuel tank, and a controller. The steering cylinder is connected to the steering gear, the steering gear is connected to the priority valve, the priority valve is connected to the active variable displacement piston pump, the engine is connected to the active variable displacement piston pump, the fuel tank is connected to the steering gear, the priority valve, and the active variable displacement piston pump, and the controller is connected to the engine and the active variable displacement piston pump. The controller outputs a control current to the active variable displacement piston pump according to the engine speed, so that the active variable displacement piston pump outputs a constant amount of hydraulic fluid.

[0006] Optionally, a pressure sensor is connected to the oil circuit between the steering gear and the priority valve. The pressure sensor is used to detect the oil pressure in the oil circuit when the vehicle is steering. The pressure sensor is electrically connected to the controller. When the vehicle is steering, the pressure sensor outputs a pressure signal, and the controller receives the pressure signal and then collects the engine speed.

[0007] Optionally, the oil circuit between the steering gear and the priority valve includes a first oil circuit and a second oil circuit. The priority valve outputs oil to the steering gear through the first oil circuit, and the pressure sensor is connected to the second oil circuit. When the vehicle turns, the oil in the steering gear is input into the second oil circuit.

[0008] Optionally, the oil tank is connected to the steering gear and the priority valve via a return oil line, and a filter is connected to the return oil line.

[0009] Optionally, the return oil line includes a third oil line, a fourth oil line, and a fifth oil line. One end of the third oil line is connected to the second oil line, and the other end of the third oil line is connected to the oil tank. One end of the fourth oil line is connected to the steering gear, and the other end of the fourth oil line is connected to the third oil line. One end of the fifth oil line is connected to the priority valve, and the other end of the fifth oil line is connected to the oil tank.

[0010] Optionally, the vehicle hydraulic steering system further includes a first relief valve, which is connected to the third oil line between the second oil line and the fourth oil line.

[0011] Optionally, the steering cylinder includes at least one first cylinder and at least one second cylinder, wherein the first cylinder is connected to the steering gear via a sixth hydraulic circuit, and the second cylinder is connected to the steering gear via a seventh hydraulic circuit.

[0012] Optionally, a first protection oil circuit is connected between the sixth oil circuit and the seventh oil circuit. A second relief valve and a third relief valve are connected to the first protection oil circuit. An eighth oil circuit is connected between the second relief valve and the third relief valve. The eighth oil circuit is connected to the third oil circuit.

[0013] Optionally, a second protective oil circuit is connected between the sixth oil circuit and the seventh oil circuit. A first check valve and a second check valve are connected to the second protective oil circuit. The second protective oil circuit between the first check valve and the second check valve is connected to the third oil circuit.

[0014] This application also relates to a dump truck, including the aforementioned vehicle hydraulic steering system.

[0015] The vehicle hydraulic steering system of this utility model controls the real-time displacement of the active variable piston pump by sending a control current through the controller, thereby reducing the matching loss caused by the incompatibility between the hydraulic steering system and the load, so as to achieve the purpose of energy saving. It can also ensure the consistency of steering performance under different working conditions of the vehicle during steering operation. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the vehicle hydraulic steering system of this application.

[0017] Figure 2 This is a coordinate graph of the active variable displacement piston pump displacement control curve of this application.

[0018] Figure 3This is a graph showing the relationship between the control current of the active variable piston pump and the engine speed. Detailed Implementation

[0019] The following specific embodiments illustrate the implementation of this application. Those skilled in the art can easily understand other advantages and effects of this application from the content disclosed in this specification.

[0020] In the following description, reference is made to the accompanying drawings, which illustrate several embodiments of the present application. It should be understood that other embodiments may also be used, and changes in mechanical composition, structure, electrical and operational aspects may be made without departing from the spirit and scope of the present application. The following detailed description should not be considered limiting, and the terminology used herein is for describing particular embodiments only and is not intended to limit the present application.

[0021] Although the terms first, second, etc., are used in some instances to describe various elements herein, these elements should not be limited by these terms. These terms are only used to distinguish one element from another.

[0022] Furthermore, as used herein, the singular forms “a,” “an,” and “the” are intended to include the plural forms as well, unless the context indicates otherwise. It should be further understood that the terms “comprising,” “including,” indicate the presence of a feature, step, operation, element, component, item, kind, and / or group, but do not exclude the presence, occurrence, or addition of one or more other features, steps, operations, elements, components, items, kinds, and / or groups. The terms “or” and “and / or” as used herein are interpreted as inclusive, or mean any one or any combination thereof. Thus, “A, B, or C” or “A, B, and / or C” means “any one of: A; B; C; A and B; A and C; B and C; A, B, and C.” Exceptions to this definition arise only when combinations of elements, functions, steps, or operations are inherently mutually exclusive in some way.

[0023] Figure 1 This is a schematic diagram of the vehicle hydraulic steering system of this application. Figure 2 This is a coordinate graph of the displacement control curve of the active variable piston pump of this application. Figure 3 This is a graph showing the relationship between the control current of the active variable displacement piston pump and the engine speed, as described in this application. Figure 1 , Figure 2 and Figure 3As shown, the vehicle hydraulic steering system includes a steering cylinder 11, a steering gear 12, a priority valve 13, an active variable displacement piston pump 14, an engine 15, an oil tank 16, and a controller (not shown). The steering cylinder 11 is connected to the steering gear 12, the steering gear 12 is connected to the priority valve 13, the priority valve 13 is connected to the active variable displacement piston pump 14, the engine 15 is connected to the active variable displacement piston pump 14, the oil tank 16 is connected to the steering gear 12, the priority valve 13, and the active variable displacement piston pump 14, and the controller is connected to the engine 15 and the active variable displacement piston pump 14. The controller outputs a control current to the active variable displacement piston pump 14 according to the engine speed of the engine 15, so that the active variable displacement piston pump 14 outputs a constant amount of oil. In this embodiment, the active variable displacement piston pump 14 achieves displacement variation by changing the stroke or the number of pistons.

[0024] like Figure 2 and Figure 3 As shown, the controller outputs a control current that varies according to the engine speed of the engine 15. The magnitude of the control current is inversely proportional to the engine speed of the engine 15. That is, the higher the engine speed of the engine 15, the lower the control current, and the lower the engine speed of the engine 15, the higher the control current. The displacement of the active variable piston pump 14 is adjusted by the current to ensure that the active variable piston pump 14 can output oil at a constant rate. Especially when the vehicle is turning, the constant oil output of the active variable piston pump 14 can ensure consistent vehicle steering performance.

[0025] When the vehicle is not being steered, the active variable displacement piston pump 14 is adjusted by the control current. At this time, the displacement of the active variable displacement piston pump 14 is at its minimum, and it outputs a small amount of oil flow to maintain standby. This makes the hydraulic steering system almost free from unloading energy loss under standby conditions, avoiding unnecessary energy loss and reducing oil filter maintenance costs.

[0026] The vehicle hydraulic steering system of this application controls the real-time displacement of the active variable piston pump 14 by sending a control current through the controller, thereby reducing the matching loss caused by the incompatibility between the hydraulic steering system and the load, so as to achieve the purpose of energy saving. It can also ensure the consistency of steering performance under different working conditions of the vehicle during steering operation.

[0027] Optionally, the output flow rate of the active variable displacement piston pump 14 can be calculated according to the following formula:

[0028] Q = i × n × q × η

[0029] In the formula:

[0030] Q: Output flow

[0031] i: Speed ​​Ratio

[0032] n: Engine speed 15 RPM

[0033] q: Pump displacement

[0034] η: Pump volumetric efficiency

[0035] In the formula, the volumetric efficiency and speed ratio of the active variable piston pump 14 are constant parameters obtained according to different vehicle selections. Therefore, in order to ensure that the output flow rate Q of the active variable piston pump 14 is constant under different operating conditions, the product of the pump displacement q and the engine speed n should be a constant value. That is, the pump displacement decreases as the engine speed n increases, and the product of the two is a constant value, and the two are inversely proportional.

[0036] Optionally, such as Figure 1 As shown, a pressure sensor 17 is connected to the oil circuit between the steering gear 12 and the priority valve 13. The pressure sensor 17 is used to detect the oil pressure in the oil circuit when the vehicle is turning. The pressure sensor 17 is electrically connected to the controller. When the vehicle is turning, the pressure sensor 17 outputs a pressure signal. The controller determines whether the vehicle is turning based on the real-time pressure signal. After receiving the pressure signal, the controller collects the engine speed of the engine 15. The controller outputs a changing control current based on the engine speed of the engine 15, and then adjusts the displacement of the active variable displacement piston pump 14. According to various operating conditions, it achieves stepless adjustment from near-zero displacement to maximum displacement, so that the hydraulic steering system has almost no unloading energy loss in standby conditions. When the vehicle is not turning, the pressure sensor 17 does not output pressure data.

[0037] Optionally, the oil circuit between the steering gear 12 and the priority valve 13 includes a first oil circuit 181 and a second oil circuit 182. The priority valve 13 outputs oil to the steering gear 12 through the first oil circuit 181, and the pressure sensor 17 is connected to the second oil circuit 182. When the vehicle is turning, the oil in the steering gear 12 is input into the second oil circuit 182.

[0038] Optionally, the oil tank 16 is connected to the steering gear 12 and the priority valve 13 via a return oil line, and a filter 21 is connected to the return oil line. The active variable displacement piston pump 14 of this application can output a constant amount of oil, avoiding a large amount of oil returning to the oil tank 16 through the filter 21, which can extend the replacement cycle of the filter 21 and reduce the maintenance cost of the oil filter.

[0039] Optionally, the return oil line includes a third oil line 183, a fourth oil line 184, and a fifth oil line 185. One end of the third oil line 183 is connected to the second oil line 182, and the other end of the third oil line 183 is connected to the oil tank 16. One end of the fourth oil line 184 is connected to the steering gear 12, and the other end of the fourth oil line 184 is connected to the third oil line 183. One end of the fifth oil line 185 is connected to the priority valve 13, and the other end of the fifth oil line 185 is connected to the oil tank 16.

[0040] Optionally, the vehicle hydraulic steering system also includes a first relief valve 221, which is connected to a third oil passage 183 between the second oil passage 182 and the fourth oil passage 184. When the oil pressure in the second oil passage 182 is too high, the oil in the second oil passage 182 can return to the oil tank 16 through the first relief valve 221 and the third oil passage 183, thus protecting the second oil passage 182.

[0041] Optionally, the steering cylinder 11 includes at least one first cylinder and at least one second cylinder. The first cylinder is connected to the steering gear 12 via a sixth hydraulic passage 186, and the second cylinder is connected to the steering gear 12 via a seventh hydraulic passage 187. In this embodiment, the sixth hydraulic passage 186 is connected to the first port of the first cylinder via a first branch, and the sixth hydraulic passage 186 is connected to the first port of the second cylinder via a second branch; the seventh hydraulic passage 187 is connected to the second port of the first cylinder via a third branch, and the seventh hydraulic passage 187 is connected to the second port of the second cylinder via a fourth branch.

[0042] When oil enters the sixth oil passage 186, the oil in the sixth oil passage 186 enters the first oil cylinder and the second oil cylinder through the first branch and the second branch respectively. At the same time, the oil in the first oil cylinder enters the seventh oil passage 187 through the third branch, and the oil in the second oil cylinder enters the seventh oil passage 187 through the fourth branch. When oil enters the seventh oil passage 187, the oil in the seventh oil passage 187 enters the first oil cylinder and the second oil cylinder through the third branch and the fourth branch respectively. At the same time, the oil in the first oil cylinder enters the sixth oil passage 186 through the first branch, and the oil in the first oil cylinder enters the sixth oil passage 186 through the second branch.

[0043] Optionally, a first protective oil circuit 191 is connected between the sixth oil circuit 186 and the seventh oil circuit 187. A second relief valve 222 and a third relief valve 223 are connected to the first protective oil circuit 191. An eighth oil circuit 188 is connected between the second relief valve 222 and the third relief valve 223, and the eighth oil circuit 188 is connected to the third oil circuit 183. When the oil pressure in the sixth oil circuit 186 is too high, the oil in the sixth oil circuit 186 can enter the eighth oil circuit 188 through the second relief valve 222, thereby protecting the sixth oil circuit 186. Similarly, when the oil pressure in the seventh oil circuit 187 is too high, the oil in the seventh oil circuit 187 can enter the eighth oil circuit 188 through the third relief valve 223, thereby protecting the seventh oil circuit 187.

[0044] Optionally, a second protective oil passage 192 is connected between the sixth oil passage 186 and the seventh oil passage 187. A first check valve 231 and a second check valve 232 are connected to the second protective oil passage 192, and the second protective oil passage 192 between the first check valve 231 and the second check valve 232 is connected to the third oil passage 183. In this embodiment, the oil in the eighth oil passage 188 can also enter the sixth oil passage 186 through the first check valve 231, or enter the seventh oil passage 187 through the second check valve 232.

[0045] This application also relates to a dump truck, including the aforementioned vehicle hydraulic steering system.

[0046] The above embodiments are merely illustrative of the principles and effects of this application and are not intended to limit this application. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of this application. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in this application should still be covered by the claims of this application.

Claims

1. A vehicle hydraulic steering system, characterized in that, The system includes a steering cylinder, a steering gear, a priority valve, an active variable displacement piston pump, an engine, a fuel tank, and a controller. The steering cylinder is connected to the steering gear, the steering gear is connected to the priority valve, the priority valve is connected to the active variable displacement piston pump, the engine is connected to the active variable displacement piston pump, the fuel tank is connected to the steering gear, the priority valve, and the active variable displacement piston pump, and the controller is connected to the engine and the active variable displacement piston pump. The controller outputs a control current to the active variable displacement piston pump according to the engine speed, so that the active variable displacement piston pump outputs a constant amount of oil.

2. The vehicle hydraulic steering system as described in claim 1, characterized in that, A pressure sensor is connected to the oil circuit between the steering gear and the priority valve. The pressure sensor is used to detect the oil pressure in the oil circuit when the vehicle is steering. The pressure sensor is electrically connected to the controller. When the vehicle is steering, the pressure sensor outputs a pressure signal. The controller receives the pressure signal and then collects the engine speed.

3. The vehicle hydraulic steering system as described in claim 2, characterized in that, The oil circuit between the steering gear and the priority valve includes a first oil circuit and a second oil circuit. The priority valve outputs oil to the steering gear through the first oil circuit. The pressure sensor is connected to the second oil circuit. When the vehicle turns, the oil in the steering gear is input into the second oil circuit.

4. The vehicle hydraulic steering system as described in claim 3, characterized in that, The oil tank is connected to the steering gear and the priority valve via a return oil line, and a filter is connected to the return oil line.

5. The vehicle hydraulic steering system as described in claim 4, characterized in that, The return oil line includes a third oil line, a fourth oil line, and a fifth oil line. One end of the third oil line is connected to the second oil line, and the other end of the third oil line is connected to the oil tank. One end of the fourth oil line is connected to the steering gear, and the other end of the fourth oil line is connected to the third oil line. One end of the fifth oil line is connected to the priority valve, and the other end of the fifth oil line is connected to the oil tank.

6. The vehicle hydraulic steering system as described in claim 5, characterized in that, The vehicle hydraulic steering system also includes a first relief valve, which is connected to the third oil line between the second oil line and the fourth oil line.

7. The vehicle hydraulic steering system as described in claim 5, characterized in that, The steering cylinder includes at least one first cylinder and at least one second cylinder. The first cylinder is connected to the steering gear via a sixth hydraulic circuit, and the second cylinder is connected to the steering gear via a seventh hydraulic circuit.

8. The vehicle hydraulic steering system as described in claim 7, characterized in that, A first protection oil circuit is connected between the sixth oil circuit and the seventh oil circuit. A second overflow valve and a third overflow valve are connected to the first protection oil circuit. An eighth oil circuit is connected between the second overflow valve and the third overflow valve. The eighth oil circuit is connected to the third oil circuit.

9. The vehicle hydraulic steering system as described in claim 8, characterized in that, A second protective oil circuit is connected between the sixth oil circuit and the seventh oil circuit. A first check valve and a second check valve are connected to the second protective oil circuit. The second protective oil circuit between the first check valve and the second check valve is connected to the third oil circuit.

10. A dump truck, characterized in that, Includes the vehicle hydraulic steering system as described in any one of claims 1 to 9.

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