Brake hydraulic system and engineering machine

Abstract

The utility model belongs to the technical field of engineering machinery, disclose brake hydraulic system and engineering machinery. Brake hydraulic system provided by the utility model adopts travel brake, can provide reliable braking force, through parallel connection of two travel brake valves and an electric proportional brake valve, judge through first shuttle valve and second shuttle valve and supply the oil pressure maximum one way to travel brake oil cylinder, make that automatic signal and the initiative operation of driver can be perfect coordination, avoid conflict, and the system is relatively simple, and the reliability is high.

Description

Technical Field

[0001] This utility model relates to the field of engineering machinery technology, and in particular to a braking hydraulic system and engineering machinery. Background Technology

[0002] Heavy-duty forklifts, due to their large size, have larger blind spots, resulting in more severe injuries and losses in the event of a collision. Therefore, there is a need to develop active safety systems for heavy-duty forklifts that better meet actual safety requirements. Current mainstream solutions involve introducing AI-based collision avoidance technology. This involves using sensors such as LiDAR, millimeter-wave radar, and cameras to perceive the environment, detect obstacles, and measure distances. The system then analyzes risks through algorithms, providing early warnings and automatic braking to prevent collisions. However, these algorithms ultimately rely on a reliable braking execution system to ensure safe operation.

[0003] Currently, there are three main methods for combining collision avoidance control algorithms with braking execution, but each has its own obvious drawbacks:

[0004] 1) Power cut-off + reverse braking: This involves cutting off the power output of the engine or motor and using the resistance of the power system to slow down the vehicle. This method is mainly applicable to electric or hydraulically driven forklifts and cannot cover all types (such as traditional internal combustion engine forklifts); furthermore, relying solely on reverse braking by the power system may not provide sufficient braking force to achieve effective deceleration in emergency situations.

[0005] 2) Controlling the parking brake valve, i.e., directly controlling the brake valve used for parking through an algorithm to achieve braking. The parking brake is designed to keep the vehicle stationary, not to dynamically decelerate. The braking torque it provides is usually small and cannot meet the emergency braking needs of high-speed driving. Furthermore, the parking brake valve is an on / off valve. Once triggered, the braking force will reach its maximum instantaneously, which will cause the vehicle to brake suddenly and stop abruptly. If there is cargo on the forks, the huge inertia can easily cause the cargo to slip and fall, which may lead to secondary safety accidents.

[0006] 3) Control the service brakes, that is, directly control the service brake system used for daily deceleration. This method can provide powerful and controllable braking force, but it must be designed properly to ensure that the automatic braking system and the driver's active operation (such as stepping on the brake) can be perfectly coordinated to avoid conflict. Utility Model Content

[0007] The purpose of this utility model is to provide a braking hydraulic system and engineering machinery that uses a service brake to provide reliable braking force, and the automatic signals and driver's active operation can be perfectly coordinated. In addition, the system is relatively simple and highly reliable.

[0008] To achieve this objective, the present invention adopts the following technical solution:

[0009] A brake hydraulic system includes an oil tank, a brake pump, a charging valve, an accumulator, two service brake valves, a first shuttle valve, an electro-proportional brake valve, a second shuttle valve, and a service brake cylinder. The inlet of the brake pump is connected to the oil tank, and the outlet of the brake pump is connected to the inlet of the charging valve. The outlet of the charging valve is connected to the accumulator, the inlets of the two service brake valves, and the inlet of the electro-proportional brake valve. The two service brake valves are arranged side by side. The working port of one service brake valve is connected to the first port of the first shuttle valve, and the working port of the other service brake valve is connected to the second port of the first shuttle valve. The third port of the first shuttle valve is connected to the first port of the second shuttle valve. The working port of the electro-proportional brake valve is connected to the second port of the second shuttle valve, and the third port of the second shuttle valve is connected to the service brake cylinder. The return ports of the two service brake valves, the return port of the electro-proportional brake valve, and the return port of the charging valve are all connected to the oil tank.

[0010] As a preferred technical solution for the brake hydraulic system, it also includes a service brake pressure switch, which is installed on the connecting pipeline between the third port of the second shuttle valve and the service brake cylinder.

[0011] As a preferred technical solution for the brake hydraulic system, it also includes a parking brake valve and a parking brake cylinder. The oil inlet of the parking brake valve is connected to the working oil port of the filling valve, the working oil port of the parking brake valve is connected to the parking brake cylinder, and the oil return port of the parking brake valve is connected to the oil tank.

[0012] As a preferred technical solution for the brake hydraulic system, it also includes a parking brake pressure switch, which is installed on the connecting pipeline between the working port of the parking brake valve and the parking brake cylinder.

[0013] As a preferred technical solution for the brake hydraulic system, the parking brake valve includes a first directional valve and a first check valve. The oil inlet of the parking brake valve is connected to the oil inlet of the first check valve, the oil outlet of the first check valve is connected to the oil inlet of the first directional valve, the working oil port of the first directional valve is connected to the working oil port of the parking brake valve, and the oil return port of the first directional valve is connected to the oil return port of the parking brake valve.

[0014] As a preferred technical solution for the brake hydraulic system, it also includes a low-pressure alarm pressure switch, which is installed on the connecting pipeline between the oil inlet of the parking brake valve and the oil inlet of the first check valve.

[0015] As a preferred technical solution for the brake hydraulic system, the filling valve includes a proportional valve and a second directional valve. The oil inlet of the filling valve is connected to the oil inlet of the proportional valve, the first control terminal of the proportional valve, the oil inlet of the second directional valve, the first control terminal of the second directional valve, and the working oil port of the filling valve. The oil outlet of the proportional valve is connected to the oil return port of the filling valve. The working oil port of the second directional valve is connected to the second control terminal of the second directional valve and the second control terminal of the proportional valve.

[0016] As a preferred technical solution for the brake hydraulic system, the filling valve further includes a second check valve, which is disposed on the connecting pipeline between the oil inlet of the filling valve and the working oil port of the filling valve.

[0017] As a preferred technical solution for the brake hydraulic system, a filter is also included, which is disposed on the connecting pipeline between the oil outlet of the brake pump and the oil inlet of the filling valve.

[0018] Construction machinery, including the braking hydraulic system described in any of the above embodiments.

[0019] The beneficial effects of this utility model are:

[0020] The braking hydraulic system provided in this embodiment of the utility model adopts a service brake, which can provide reliable braking force. By connecting two service brake valves and one electric proportional brake valve in parallel, and after judging by the first shuttle valve and the second shuttle valve, the one with the largest oil pressure is supplied to the service brake cylinder, so that the automatic signal and the driver's active operation can be perfectly coordinated to avoid conflict. Moreover, the system is relatively simple and highly reliable. Attached Figure Description

[0021] Figure 1 This is a hydraulic schematic diagram of the braking hydraulic system provided in this embodiment of the utility model.

[0022] In the picture:

[0023] 10. Fuel tank; 20. Brake pump; 30. Filter; 40. Filling valve; 401. Proportional valve; 402. Second directional valve; 403. Second check valve; 50. Accumulator; 60. Service brake valve; 70. Electro-proportional brake valve; 80. First shuttle valve; 90. Second shuttle valve; 100. Service brake cylinder; 110. Service brake pressure switch; 120. Parking brake valve; 121. First directional valve; 122. First check valve; 130. Parking brake cylinder; 140. Parking brake pressure switch; 150. Low pressure alarm pressure switch. Detailed Implementation

[0024] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, not the entire structure.

[0025] In the description of this utility model, unless otherwise explicitly specified and limited, the terms "connected," "linked," and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0026] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0027] In the description of this embodiment, the terms "upper," "lower," "right," etc., refer to the orientation or positional relationship shown in the accompanying drawings. They are used only for ease of description and simplification of operation, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model. In addition, the terms "first" and "second" are only used for distinction in description and have no special meaning.

[0028] like Figure 1As shown, this utility model embodiment provides a brake hydraulic system, including an oil tank 10, a brake pump 20, a filling valve 40, an accumulator 50, two service brake valves 60, a first shuttle valve 80, an electro-proportional brake valve 70, a second shuttle valve 90, and a service brake cylinder 100. The oil inlet of the brake pump 20 is connected to the oil tank 10, and the oil outlet of the brake pump 20 is connected to the oil inlet of the filling valve 40. The oil outlet of the filling valve 40 is connected to the oil inlets of the accumulator 50, the two service brake valves 60, and the electro-proportional brake valve 70. The two service brake valves 60... The oil tank is arranged in parallel, with the working port of one service brake valve 60 connected to the first port of the first shuttle valve 80, the working port of the other service brake valve 60 connected to the second port of the first shuttle valve 80, the third port of the first shuttle valve 80 connected to the first port of the second shuttle valve 90, the working port of the electric proportional brake valve 70 connected to the second port of the second shuttle valve 90, and the third port of the second shuttle valve 90 connected to the service brake cylinder 100. The return ports of the two service brake valves 60, the return port of the electric proportional brake valve 70, and the return port of the filling valve 40 are all connected to the oil tank 10.

[0029] The brake hydraulic system provided in this embodiment of the utility model is configured with two service brake valves 60 and one electro-proportional brake valve 70. When the brake pedal corresponding to one of the two service brake valves 60 is depressed, the oil in the accumulator 50 passes through the service brake valve 60, the first shuttle valve 80, and the second shuttle valve 90 before entering the service brake cylinder 100 to achieve service braking. When the brake pedals corresponding to each of the two service brake valves 60 are depressed respectively, the oil in the accumulator 50 flows through the two service brake valves 60 to the first port and the second port of the first shuttle valve 80. The first shuttle valve 80 selects the output with the higher oil pressure, and the oil flows through the second shuttle valve 90 before entering the service brake cylinder 100. The system achieves service braking. When the electric proportional brake valve 70 receives a service braking signal, the oil in the accumulator 50 enters the service brake cylinder 100 after passing through the electric proportional brake valve 70 and the second shuttle valve 90, thus achieving service braking. When the brake pedal corresponding to at least one service brake valve 60 is pressed and the electric proportional brake valve 70 receives a service braking signal, the first shuttle valve 80 first selects the one with the higher oil pressure among the two service brake valves 60 and outputs it to the first port of the second shuttle valve 90. At the same time, the oil from the electric proportional brake valve 70 is output to the second port of the second shuttle valve 90. Then, the second shuttle valve 90 selects the one with the higher oil pressure and outputs it to the service brake cylinder 100, thus achieving service braking.

[0030] The braking hydraulic system provided in this embodiment of the utility model adopts a service brake, which can provide reliable braking force. By connecting two service brake valves 60 and one electric proportional brake valve 70 in parallel, and after judging by the first shuttle valve 80 and the second shuttle valve 90, the one with the largest oil pressure is supplied to the service brake cylinder 100, so that the automatic signal (i.e. the braking signal received by the electric proportional brake valve 70) and the driver's active operation (i.e. the driver stepping on the brake pedal) can be perfectly coordinated to avoid conflict. Moreover, the system is relatively simple and has high reliability.

[0031] Specifically, the service brake valve 60 includes a first working position and a second working position. When the service brake valve 60 is in the first working position, the oil inlet and the working oil port of the service brake valve 60 are connected. At this time, the oil in the accumulator 50 can flow to the service brake cylinder 100 through the service brake valve 60. When the service brake valve 60 is in the second working position, the working oil port and the return oil port of the service brake valve 60 are connected. At this time, the oil in the service brake cylinder 100 can flow back to the oil tank 10 through the service brake valve 60.

[0032] The electric proportional brake valve 70 includes a first working position and a second working position. When the electric proportional brake valve 70 is in the first working position, the oil inlet and the working oil port of the electric proportional brake valve 70 are connected. At this time, the oil in the accumulator 50 can flow to the service brake cylinder 100 through the electric proportional brake valve 70. When the electric proportional brake valve 70 is in the second working position, the working oil port and the return oil port of the electric proportional brake valve 70 are connected. At this time, the oil in the service brake cylinder 100 can flow back to the oil tank 10 through the electric proportional brake valve 70.

[0033] In this embodiment, the brake hydraulic system also includes a service brake pressure switch 110. The service brake pressure switch 110 is located on the connecting pipeline between the third port of the second shuttle valve 90 and the service brake cylinder 100. The service brake pressure switch 110 is electrically connected to the controller of the construction machinery. The service brake pressure switch 110 has the function of monitoring the braking status and providing signal feedback. When the service brake is applied, hydraulic fluid enters the service brake cylinder 100 through the second shuttle valve 90, increasing the pipeline pressure and activating the service brake pressure switch 110. When the service brake is released, the hydraulic fluid in the service brake cylinder 100 flows back to the oil tank 10, releasing the pipeline pressure and deactivating the service brake pressure switch 110. The controller can determine whether service braking has occurred based on the on / off signal of the service brake pressure switch 110. When the controller determines that service braking is in progress, it can control the brake lights at the rear of the vehicle and / or the brake lights on the dashboard to illuminate.

[0034] The brake hydraulic system provided in this embodiment of the utility model also includes a parking brake valve 120 and a parking brake cylinder 130. The oil inlet of the parking brake valve 120 is connected to the working oil port of the filling valve 40, the working oil port of the parking brake valve 120 is connected to the parking brake cylinder 130, and the oil return port of the parking brake valve 120 is connected to the oil tank 10.

[0035] In this embodiment, the parking brake valve 120 includes a first directional valve 121 and a first check valve 122. The oil inlet of the parking brake valve 120 is connected to the oil inlet of the first check valve 122, the oil outlet of the first check valve 122 is connected to the oil inlet of the first directional valve 121, the working oil port of the first directional valve 121 is connected to the working oil port of the parking brake valve 120, and the oil return port of the first directional valve 121 is connected to the oil return port of the parking brake valve 120. The first directional valve 121 has a first working position and a second working position. When the first directional valve 121 is in the first working position, the oil inlet of the first directional valve 121 is connected to the working oil port. At this time, the oil flowing out of the filling valve 40 enters the parking brake cylinder 130 through the first check valve 122 and the first directional valve 121 to release the parking brake. When the first directional valve 121 is in the second working position, the working oil port of the first directional valve 121 is connected to the return oil port. At this time, the oil in the parking brake cylinder 130 flows back to the oil tank 10 through the first directional valve 121 to realize the parking brake.

[0036] In this embodiment, the brake hydraulic system also includes a parking brake pressure switch 140. The parking brake pressure switch 140 is located on the connecting pipeline between the working port of the parking brake valve 120 and the parking brake cylinder 130, and is electrically connected to the controller of the construction machinery. The parking brake pressure switch 140 has the function of monitoring the parking brake status. When the parking brake is released, hydraulic fluid enters the parking brake cylinder 130 through the parking brake valve 120, increasing the pipeline pressure and activating the parking brake pressure switch 140. When the parking brake is applied, the hydraulic fluid in the parking brake cylinder 130 flows back to the oil tank 10, releasing the pipeline pressure and deactivating the parking brake pressure switch 140. The controller can determine the actual working state of the parking brake based on the on / off signal of the parking brake pressure switch 140. When the controller detects that the parking brake pressure switch 140 is deactivated, it can illuminate the parking brake warning light on the instrument panel; when the controller detects that the parking brake pressure switch 140 is activated, it can extinguish the parking brake warning light on the instrument panel.

[0037] In this embodiment, the brake hydraulic system also includes a low-pressure alarm switch 150. The low-pressure alarm switch 150 is disposed on the connecting pipeline between the oil inlet of the parking brake valve 120 and the oil inlet of the first check valve 122. The low-pressure alarm switch 150 is electrically connected to the controller of the construction machinery. The low-pressure alarm switch 150 is used to provide a signal to the controller when the brake pressure of the brake hydraulic system is abnormal.

[0038] In this embodiment, the filling valve 40 includes a proportional valve 401 and a second directional valve 402. The oil inlet of the filling valve 40 is connected to the oil inlet of the proportional valve 401, the first control terminal of the proportional valve 401, the oil inlet of the second directional valve 402, the first control terminal of the second directional valve 402, and the working oil port of the filling valve 40. The oil outlet of the proportional valve 401 is connected to the oil return port of the filling valve 40. The working oil port of the second directional valve 402 is connected to the second control terminal of the second directional valve 402 and the second control terminal of the proportional valve 401. The proportional valve 401 has a conducting working position and a disconnected working position. When the proportional valve 401 is in the conducting working position, the oil inlet and outlet of the proportional valve 401 are connected; when the proportional valve 401 is in the disconnected working position, the oil inlet and outlet of the proportional valve 401 are disconnected. The second directional valve 402 has a first working position and a second working position. When the second directional valve 402 is in the first working position, the oil inlet of the second directional valve 402 is connected to the working oil port; when the second directional valve 402 is in the second working position, the working oil port of the second directional valve 402 is connected to the return oil port. When the charging valve 40 charges the accumulator 50, the proportional valve 401 is in the off position and the second directional valve 402 is in the first working position. The oil flowing out of the brake pump 20 flows into the charging valve 40 through the inlet of the charging valve 40, and then flows to the working port of the charging valve 40 through the connecting pipe between the inlet and working port of the charging valve 40, and then flows to the accumulator 50. When the accumulator 50 is full of oil, the system pressure increases, and the oil acts on the first control end of the proportional valve 401 and the first control end of the second directional valve 402. The proportional valve 401 switches to the on position and the second directional valve 402 switches to the second working position. The oil flows back to the oil tank 10 through the on position of the proportional valve 401 and the second working position of the second directional valve 402.

[0039] Furthermore, the filling valve 40 also includes a second check valve 403, which is disposed on the connecting pipeline between the oil inlet of the filling valve 40 and the working oil port of the filling valve 40 to prevent oil backflow.

[0040] In this embodiment, the brake hydraulic system further includes a filter 30, which is disposed on the connecting pipeline between the oil outlet of the brake pump 20 and the oil inlet of the filling valve 40 to filter the oil and prevent impurities from entering the system.

[0041] This utility model embodiment also provides an engineering machinery, including the above-described braking hydraulic system. In this embodiment, the engineering machinery is a heavy-duty forklift or a heavy-duty truck.

[0042] Obviously, the above embodiments of this utility model are merely examples for clearly illustrating the present utility model, and are not intended to limit the implementation of the present utility model. Those skilled in the art can make various obvious changes, readjustments, and substitutions without departing from the protection scope of this utility model. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this utility model should be included within the protection scope of the claims of this utility model.

Claims

1. A braking hydraulic system, characterized in that, The system includes an oil tank (10), a brake pump (20), a filling valve (40), an accumulator (50), two service brake valves (60), a first shuttle valve (80), an electric proportional brake valve (70), a second shuttle valve (90), and a service brake cylinder (100). The inlet of the brake pump (20) is connected to the oil tank (10), and the outlet of the brake pump (20) is connected to the inlet of the filling valve (40). The outlet of the filling valve (40) is connected to the inlets of the accumulator (50), the two service brake valves (60), and the electric proportional brake valve (70). The two service brake valves (60) are arranged side by side, one of which... The working port of the service brake valve (60) is connected to the first port of the first shuttle valve (80), the working port of the other service brake valve (60) is connected to the second port of the first shuttle valve (80), the third port of the first shuttle valve (80) is connected to the first port of the second shuttle valve (90), the working port of the electric proportional brake valve (70) is connected to the second port of the second shuttle valve (90), the third port of the second shuttle valve (90) is connected to the service brake cylinder (100), and the return ports of the two service brake valves (60), the return port of the electric proportional brake valve (70), and the return port of the filling valve (40) are all connected to the oil tank (10).

2. The braking hydraulic system according to claim 1, characterized in that, It also includes a service brake pressure switch (110), which is located on the connecting pipeline between the third port of the second shuttle valve (90) and the service brake cylinder (100).

3. The braking hydraulic system according to claim 1, characterized in that, It also includes a parking brake valve (120) and a parking brake cylinder (130). The oil inlet of the parking brake valve (120) is connected to the working oil port of the filling valve (40), the working oil port of the parking brake valve (120) is connected to the parking brake cylinder (130), and the oil return port of the parking brake valve (120) is connected to the oil tank (10).

4. The braking hydraulic system according to claim 3, characterized in that, It also includes a parking brake pressure switch (140), which is located on the connecting pipeline between the working port of the parking brake valve (120) and the parking brake cylinder (130).

5. The braking hydraulic system according to claim 3, characterized in that, The parking brake valve (120) includes a first directional valve (121) and a first check valve (122). The oil inlet of the parking brake valve (120) is connected to the oil inlet of the first check valve (122). The oil outlet of the first check valve (122) is connected to the oil inlet of the first directional valve (121). The working oil port of the first directional valve (121) is connected to the working oil port of the parking brake valve (120). The return oil port of the first directional valve (121) is connected to the return oil port of the parking brake valve (120).

6. The braking hydraulic system according to claim 5, characterized in that, It also includes a low-pressure alarm pressure switch (150), which is located on the connecting pipeline between the oil inlet of the parking brake valve (120) and the oil inlet of the first check valve (122).

7. The braking hydraulic system according to any one of claims 1-6, characterized in that, The filling valve (40) includes a proportional valve (401) and a second directional valve (402). The oil inlet of the filling valve (40) is connected to the oil inlet of the proportional valve (401), the first control terminal of the proportional valve (401), the oil inlet of the second directional valve (402), the first control terminal of the second directional valve (402), and the working oil port of the filling valve (40). The oil outlet of the proportional valve (401) is connected to the oil return port of the filling valve (40). The working oil port of the second directional valve (402) is connected to the second control terminal of the second directional valve (402) and the second control terminal of the proportional valve (401).

8. The braking hydraulic system according to claim 7, characterized in that, The filling valve (40) also includes a second check valve (403), which is disposed on the connecting pipeline between the oil inlet of the filling valve (40) and the working oil port of the filling valve (40).

9. The braking hydraulic system according to any one of claims 1-6, characterized in that, It also includes a filter (30), which is disposed on the connecting pipeline between the oil outlet of the brake pump (20) and the oil inlet of the filling valve (40).

10. Construction machinery, characterized in that, Includes the braking hydraulic system as described in any one of claims 1-9.

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