Brake hydraulic system and engineering machinery

Abstract

The invention belongs to the technical field of engineering machinery, and discloses a brake hydraulic system and engineering machinery. According to the brake hydraulic system, service braking is adopted, reliable braking force can be provided, the two service brake valves and the electric proportional brake valve are connected in parallel, the path with the largest oil pressure is supplied to the service brake oil cylinder after judgment is conducted through the first shuttle valve and the second shuttle valve, and the service brake oil cylinder is connected with the electric proportional brake valve. Automatic signals and active operation of a driver can be perfectly coordinated, conflicts are avoided, and the system is simple and high in reliability.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of engineering machinery, and in particular to a brake hydraulic system and engineering machinery. BACKGROUND

[0002] Heavy forklifts have a larger body size and a larger blind area in the peripheral vision, and once a collision occurs, the damage and loss are more serious. Therefore, it is necessary to develop an active safety system that is more in line with the actual safety needs for heavy forklifts. The current mainstream solution is to introduce AI anti-collision technology, which perceives the environment, detects obstacles and measures the distance through sensors such as laser radar, millimeter wave radar and camera, and the system analyzes the risk through algorithms to achieve early warning and automatic braking, thereby preventing collisions. However, the algorithm must ultimately be implemented through a reliable brake execution system to achieve safe action.

[0003] There are currently three methods of combining anti-collision control algorithms with brake execution, but each has obvious shortcomings:

[0004] 1) Cut off power + power drag braking, i.e., cut off the power output of the engine or motor and use the resistance of the power system to slow down the vehicle. This method is mainly suitable for electrically driven or hydraulically driven forklifts and cannot cover all types (such as traditional internal combustion engine forklifts); and only relying on power system drag, the braking force may not be sufficient to achieve effective deceleration in an emergency.

[0005] 2) Control the parking brake valve, i.e., directly control the brake valve for parking to achieve braking. The original intention of the parking brake is to maintain static, not dynamic deceleration, and its provided braking torque is usually small and cannot meet the emergency braking needs at high speeds; and the parking brake valve is an on-off valve, and once triggered, the braking force will reach the maximum instantaneously, which will cause the vehicle to suddenly stop, and if there is cargo on the forks, the huge inertia will easily cause the cargo to slip and fall, thereby causing a secondary safety accident.

[0006] 3) Control the service brake, i.e., directly control the service brake system used for daily deceleration, which can provide strong and controllable braking force, but must be reasonably designed 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 conflicts. SUMMARY

[0007] The purpose of the present application is to provide a brake hydraulic system and engineering machinery that uses a service brake to provide reliable braking force, and the automatic signal and the driver's active operation can be perfectly coordinated, and the system is simple and has high reliability.

[0008] To achieve this purpose, the present application adopts the following technical solutions:

[0009] The brake hydraulic system comprises an oil tank, a brake pump, a filling valve, an accumulator, two service brake valves, a first shuttle valve, an electric proportional brake valve, a second shuttle valve and a service brake cylinder, an oil inlet of the brake pump is communicated with the oil tank, an oil outlet of the brake pump is communicated with an oil inlet of the filling valve, an oil outlet of the filling valve is communicated with an oil inlet of the accumulator, an oil inlet of two service brake valves and an oil inlet of the electric proportional brake valve, the two service brake valves are arranged side by side, an oil port of one of the service brake valves is communicated with a first port of the first shuttle valve, an oil port of the other service brake valve is communicated with a second port of the first shuttle valve, a third port of the first shuttle valve is communicated with a first port of the second shuttle valve, an oil port of the electric proportional brake valve is communicated with a second port of the second shuttle valve, a third port of the second shuttle valve is communicated with the service brake cylinder, and an oil return port of the two service brake valves, an oil return port of the electric proportional brake valve and an oil return port of the filling valve are all communicated with the oil tank.

[0010] As a preferred technical scheme of the brake hydraulic system, a service brake pressure switch is arranged on a communication pipeline between the third port of the second shuttle valve and the service brake cylinder.

[0011] As a preferred technical scheme of the brake hydraulic system, a parking brake valve and a parking brake cylinder are further included, an oil inlet of the parking brake valve is communicated with an oil port of the filling valve, an oil port of the parking brake valve is communicated with the parking brake cylinder, and an oil return port of the parking brake valve is communicated with the oil tank.

[0012] As a preferred technical scheme of the brake hydraulic system, a parking brake pressure switch is arranged on a communication pipeline between the oil port of the parking brake valve and the parking brake cylinder.

[0013] As a preferred technical scheme of the brake hydraulic system, the parking brake valve comprises a first reversing valve and a first one-way valve, an oil inlet of the parking brake valve is communicated with an oil inlet of the first one-way valve, an oil outlet of the first one-way valve is communicated with an oil inlet of the first reversing valve, an oil port of the first reversing valve is communicated with an oil port of the parking brake valve, and an oil return port of the first reversing valve is communicated with an oil return port of the parking brake valve.

[0014] As a preferred technical scheme of the brake hydraulic system, a low-pressure alarm pressure switch is arranged on a communication pipeline between the oil inlet of the parking brake valve and the oil inlet of the first one-way valve.

[0015] As the preferred technical scheme of the brake hydraulic system, the filling valve comprises a proportional valve and a second reversing valve, an oil inlet of the filling valve is communicated with an oil inlet of the proportional valve, a first side control end of the proportional valve, an oil inlet of the second reversing valve, a first side control end of the second reversing valve and a working oil outlet of the filling valve, an oil outlet of the proportional valve is communicated with an oil return of the filling valve, and a working oil outlet of the second reversing valve is communicated with a second side control end of the second reversing valve and a second side control end of the proportional valve.

[0016] As the preferred technical scheme of the brake hydraulic system, the filling valve further comprises a second one-way valve, which is arranged on a communication pipeline between the oil inlet of the filling valve and the working oil outlet of the filling valve.

[0017] As the preferred technical scheme of the brake hydraulic system, a filter is further arranged on a communication pipeline between the oil outlet of the brake pump and the oil inlet of the filling valve.

[0018] The engineering machinery comprises the brake hydraulic system according to any one of the above schemes.

[0019] The beneficial effects of the present application are as follows:

[0020] The brake hydraulic system provided by the embodiment of the present application adopts service braking, can provide reliable braking force, and can make automatic signals and active operation of the driver perfect coordination and avoid conflicts by connecting two service brake valves and an electric proportional brake valve in parallel and supplying the oil pressure of the largest one to the service brake cylinder through the first shuttle valve and the second shuttle valve. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 is a hydraulic principle diagram of the brake hydraulic system provided by the embodiment of the present application.

[0022] In the drawings:

[0023] 10, oil tank; 20, brake pump; 30, filter; 40, filling valve; 401, proportional valve; 402, second reversing valve; 403, second one-way valve; 50, accumulator; 60, service brake valve; 70, electric 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 reversing valve; 122, first one-way valve; 130, parking brake cylinder; 140, parking brake pressure switch; 150, low-pressure alarm pressure switch. DETAILED DESCRIPTION

[0024] The application will be further described below in conjunction with the drawings and embodiments. It is to be understood that the specific embodiments described herein are merely illustrative of the application and are not to be used to limit the scope of the application. In addition, it is to be understood that, for ease of description, only the parts related to the application are shown in the drawings.

[0025] In the description of the application, unless otherwise explicitly specified and limited, the terms "connected", "connected", "fixed" should be understood broadly, for example, it can be fixedly connected, or detachably connected, or integrated; it can be mechanically connected, or electrically connected; it can be directly connected, or indirectly connected through an intermediate medium; it can be the internal communication of two elements or the interaction relationship between two elements. For those skilled in the art, the specific meaning of the above terms in the application can be understood according to the specific circumstances.

[0026] In the present application, unless otherwise explicitly specified and limited, the "upper" or "lower" of the first feature to the second feature can include that the first and second features are in direct contact, or that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, the "upper", "above" and "on" of the first feature to the second feature includes that the first feature is directly above and obliquely above the second feature, or only indicates that the horizontal height of the first feature is higher than that of the second feature. The "below", "under" and "under" of the first feature to the second feature includes that the first feature is directly below and obliquely below the second feature, or only indicates that the horizontal height of the first feature is less than that of the second feature.

[0027] In the description of the present embodiment, the terms "upper", "lower", "right", and other orientation or position relationship are based on the orientation or position relationship shown in the drawings, and are only for the convenience of description and simplification of operation, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the application. In addition, the terms "first" and "second" are only used to distinguish in the description and have no special meaning.

[0028] As Figure 1As shown, the embodiment of the present application provides a brake hydraulic system, which comprises 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 oil inlet of the brake pump 20 is communicated with the oil tank 10. The oil outlet of the brake pump 20 is communicated with the oil inlet of the filling valve 40. The oil outlet of the filling valve 40 is communicated with the oil 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. The working oil port of one of the two service brake valves 60 is communicated with the first port of the first shuttle valve 80. The working oil port of the other service brake valve 60 is communicated with the second port of the first shuttle valve 80. The third port of the first shuttle valve 80 is communicated with the first port of the second shuttle valve 90. The working oil port of the electric proportional brake valve 70 is communicated with the second port of the second shuttle valve 90. The third port of the second shuttle valve 90 is communicated with the service brake cylinder 100. The oil return ports of the two service brake valves 60, the oil return port of the electric proportional brake valve 70 and the oil return port of the filling valve 40 are all communicated with the oil tank 10.

[0029] The brake hydraulic system provided by the embodiment of the present application is configured with two service brake valves 60 and an electric proportional brake valve 70. When the brake pedal corresponding to one of the two service brake valves 60 is stepped on, the oil in the accumulator 50 flows through the service brake valve 60, the first shuttle valve 80 and the second shuttle valve 90 and then enters the service brake cylinder 100, so as to realize service braking. When the brake pedals corresponding to the two service brake valves 60 are stepped on 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 respectively. The first shuttle valve 80 selects the one with higher oil pressure and outputs. The oil flows through the second shuttle valve 90 and then enters the service brake cylinder 100, so as to realize service braking. When the electric proportional brake valve 70 receives a service brake signal, the oil in the accumulator 50 flows through the electric proportional brake valve 70 and the second shuttle valve 90 and then enters the service brake cylinder 100, so as to realize service braking. When the brake pedal corresponding to at least one of the service brake valves 60 is stepped on and the electric proportional brake valve 70 receives a service brake signal, the first shuttle valve 80 selects the one with higher oil pressure among the two service brake valves 60 and outputs to the first port of the second shuttle valve 90. At the same time, the electric proportional brake valve 70 outputs oil to the second port of the second shuttle valve 90. Then, the second shuttle valve 90 selects the one with higher oil pressure and outputs to the service brake cylinder 100, so as to realize service braking.

[0030] The brake hydraulic system provided by the embodiment of the application adopts service braking, can provide reliable braking force, and can make automatic signals (i.e., braking signals received by the electric proportional brake valve 70) and active operation of the driver (i.e., the driver stepping on the brake pedal) perfectly coordinated and avoid conflicts by connecting the two service brake valves 60 and the electric proportional brake valve 70 in parallel, judging the oil pressure of each path through the first shuttle valve 80 and the second shuttle valve 90, and supplying the path with the maximum oil pressure to the service brake cylinder 100.

[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 outlet of the service brake valve 60 are communicated, and 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 outlet and the oil return outlet of the service brake valve 60 are communicated, and 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 outlet of the electric proportional brake valve 70 are communicated, and 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 outlet and the oil return outlet of the electric proportional brake valve 70 are communicated, and 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 the embodiment, the brake hydraulic system further includes a service brake pressure switch 110, which is arranged on a communication pipeline between the third port of the second shuttle valve 90 and the service brake cylinder 100 and is electrically connected with the controller of the engineering machinery. The service brake pressure switch 110 has the functions of brake state monitoring and signal feedback. When service braking is performed, the oil enters the service brake cylinder 100 through the second shuttle valve 90, the pipeline pressure rises, the service brake pressure switch 110 is turned on, when the service braking is ended, the oil in the service brake cylinder 100 flows back to the oil tank 10, the pipeline pressure is released, the service brake pressure switch 110 is turned off, and the controller can judge whether service braking occurs according to the on-off signal of the service brake pressure switch 110. When the controller judges that service braking is occurring, the brake light at the rear of the vehicle and / or the brake light on the instrument panel can be controlled to be turned on.

[0034] The brake hydraulic system provided by the embodiment of the application further comprises a parking brake valve 120 and a parking brake cylinder 130, an oil inlet of the parking brake valve 120 is communicated with the working oil outlet of the liquid filling valve 40, a working oil outlet of the parking brake valve 120 is communicated with the parking brake cylinder 130, and an oil return outlet of the parking brake valve 120 is communicated with the oil tank 10.

[0035] In the embodiment, the parking brake valve 120 comprises a first reversing valve 121 and a first check valve 122, the oil inlet of the parking brake valve 120 is communicated with the oil inlet of the first check valve 122, the oil outlet of the first check valve 122 is communicated with the oil inlet of the first reversing valve 121, the working oil outlet of the first reversing valve 121 is communicated with the working oil outlet of the parking brake valve 120, and the oil return outlet of the first reversing valve 121 is communicated with the oil return outlet of the parking brake valve 120. The first reversing valve 121 has a first working position and a second working position, when the first reversing valve 121 is in the first working position, the oil inlet of the first reversing valve 121 is communicated with the working oil outlet, at this time, the oil flowing out of the liquid filling valve 40 enters the parking brake cylinder 130 through the first check valve 122 and the first reversing valve 121, so as to release the parking brake, when the first reversing valve 121 is in the second working position, the working oil outlet of the first reversing valve 121 is communicated with the oil return outlet, at this time, the oil in the parking brake cylinder 130 flows back to the oil tank 10 through the first reversing valve 121, so as to realize the parking brake.

[0036] In the embodiment, the brake hydraulic system further comprises a parking brake pressure switch 140, the parking brake pressure switch 140 is arranged on a communication pipeline between the working oil outlet of the parking brake valve 120 and the parking brake cylinder 130, and the parking brake pressure switch 140 is electrically connected with the controller of the engineering machinery. The parking brake pressure switch 140 has a parking brake state monitoring function, when the parking brake is released, the oil enters the parking brake cylinder 130 through the parking brake valve 120, the pipeline pressure rises, and the parking brake pressure switch 140 is turned on, when the parking brake is implemented, the oil in the parking brake cylinder 130 flows back to the oil tank 10, the pipeline pressure is released, and the parking brake pressure switch 140 is turned off, and the controller can judge the actual working state of the parking brake according to the on-off signal of the parking brake pressure switch 140. When the controller detects that the parking brake pressure switch 140 is turned off, a parking brake warning light on the instrument panel can be lighted, and when the controller detects that the parking brake pressure switch 140 is turned on, the parking brake warning light on the instrument panel can be extinguished.

[0037] In the embodiment, the brake hydraulic system further comprises a low-pressure alarm pressure switch 150, the low-pressure alarm pressure switch 150 is arranged on a communication 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 pressure switch 150 is electrically connected with the controller of the engineering machinery, and the low-pressure alarm pressure switch 150 is used for providing a signal to the controller when the brake pressure of the brake hydraulic system is abnormal.

[0038] In the embodiment, the liquid filling valve 40 comprises a proportional valve 401 and a second reversing valve 402. The oil inlet of the liquid filling valve 40 is in communication with the oil inlet of the proportional valve 401, the first side control end of the proportional valve 401, the oil inlet of the second reversing valve 402, the first side control end of the second reversing valve 402, and the working oil outlet of the liquid filling valve 40. The oil outlet of the proportional valve 401 is in communication with the oil return outlet of the liquid filling valve 40. The working oil outlet of the second reversing valve 402 is in communication with the second side control end of the second reversing valve 402 and the second side control end of the proportional valve 401. The proportional valve 401 has a conducting working position and a disconnecting working position. When the proportional valve 401 is in the conducting working position, the oil inlet of the proportional valve 401 is in communication with the oil outlet. When the proportional valve 401 is in the disconnecting working position, the oil inlet of the proportional valve 401 is disconnected from the oil outlet. The second reversing valve 402 has a first working position and a second working position. When the second reversing valve 402 is in the first working position, the oil inlet of the second reversing valve 402 is in communication with the working oil outlet. When the second reversing valve 402 is in the second working position, the working oil outlet of the second reversing valve 402 is in communication with the oil return outlet. When the liquid filling valve 40 fills the accumulator 50 with liquid, the proportional valve 401 is in the disconnecting working position, and the second reversing valve 402 is in the first working position. The oil flowing out of the brake pump 20 flows into the liquid filling valve 40 through the oil inlet of the liquid filling valve 40, and then flows to the working oil outlet of the liquid filling valve 40 through the communication pipeline between the oil inlet and the working oil outlet of the liquid filling valve 40, and then flows to the accumulator 50. When the accumulator 50 is filled with oil and the system pressure increases, the oil acts on the first side control end of the proportional valve 401 and the first side control end of the second reversing valve 402. The proportional valve 401 switches to the conducting working position, and the second reversing valve 402 switches to the second working position. The oil flows back to the oil tank 10 through the conducting position of the proportional valve 401 and the second working position of the second reversing valve 402.

[0039] Further, the liquid filling valve 40 further comprises a second one-way valve 403 arranged on the communication pipeline between the oil inlet of the liquid filling valve 40 and the working oil outlet of the liquid filling valve 40, to prevent the backflow of the oil.

[0040] In the embodiment, the brake hydraulic system further comprises a filter 30 arranged on the communication pipeline between the oil outlet of the brake pump 20 and the oil inlet of the liquid filling valve 40, to filter the oil and prevent impurities from entering the system.

[0041] The embodiment of the present application further provides an engineering machine comprising the brake hydraulic system. In the embodiment, the engineering machine is a heavy-duty forklift or a heavy-duty truck.

[0042] Obviously, the above embodiments of the present application are merely exemplary but not intended to limit the embodiments of the present application. Various obvious changes, re-adjustments and substitutions can be made by those skilled in the art without departing from the scope of the present application. It is not necessary or possible to enumerate all the embodiments. Any modification, equivalent replacement and improvement made within the spirit and principle of the present application shall be included in the protection scope of the claims of the present application.

Claims

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

2. The brake hydraulic system according to claim 1, characterized by, The brake system further comprises a service brake pressure switch (110), which is arranged on the communication pipeline between the third port of the second shuttle valve (90) and the service brake cylinder (100).

3. The brake hydraulic system according to claim 1, characterized by, The brake system further comprises a parking brake valve (120) and a parking brake cylinder (130), the oil inlet of the parking brake valve (120) is communicated with the working oil port of the filling valve (40), the working oil port of the parking brake valve (120) is communicated with the parking brake cylinder (130), and the oil return port of the parking brake valve (120) is communicated with the oil tank (10).

4. The brake hydraulic system according to claim 3, characterized by The brake system further comprises a parking brake pressure switch (140), which is arranged on the communication pipeline between the working oil port of the parking brake valve (120) and the parking brake cylinder (130).

5. The brake hydraulic system according to claim 3, characterized by The parking brake valve (120) comprises a first reversing valve (121) and a first check valve (122), the oil inlet of the parking brake valve (120) is communicated with the oil inlet of the first check valve (122), the oil outlet of the first check valve (122) is communicated with the oil inlet of the first reversing valve (121), the working oil port of the first reversing valve (121) is communicated with the working oil port of the parking brake valve (120), and the oil return port of the first reversing valve (121) is communicated with the oil return port of the parking brake valve (120).

6. The brake hydraulic system according to claim 5, characterized by The brake system further comprises a low-pressure alarm pressure switch (150), which is arranged on the communication pipeline between the oil inlet of the parking brake valve (120) and the oil inlet of the first check valve (122).

7. The brake hydraulic system according to any one of claims 1 to 6, characterized by, The liquid filling valve (40) comprises a proportional valve (401) and a second reversing valve (402), an oil inlet of the liquid filling valve (40) is communicated with an oil inlet of the proportional valve (401), a first side control end of the proportional valve (401), an oil inlet of the second reversing valve (402), a first side control end of the second reversing valve (402) and an oil outlet of the liquid filling valve (40), an oil outlet of the proportional valve (401) is communicated with an oil return of the liquid filling valve (40), an oil outlet of the second reversing valve (402) is communicated with a second side control end of the second reversing valve (402) and a second side control end of the proportional valve (401).

8. The brake hydraulic system according to claim 7, characterized by The liquid filling valve (40) further comprises a second one-way valve (403), which is arranged on a communication pipeline between the oil inlet of the liquid filling valve (40) and the oil outlet of the liquid filling valve (40).

9. The brake hydraulic system according to any one of claims 1 to 6, characterized by, A filter (30) is further included, which is arranged on a communication pipeline between the oil outlet of the brake pump (20) and the oil inlet of the liquid filling valve (40).

10. A working machine, characterised in that The brake hydraulic system comprises the brake hydraulic system according to any one of claims 1-9.

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