A service braking system

Abstract

The present invention provides a service brake system, which relates to the field of vehicle braking technology and includes a main pump, a brake combination valve, a manual control valve, a flow path switching device, a brake electric proportional valve, a first service brake, and a second service brake. When the oil pressure flowing out of the manual control valve is greater than the oil pressure flowing out of the brake electric proportional valve, the flow path switching device is used to connect port B of the brake electric proportional valve to ports PX1 and PX2 of the brake main valve. When the oil pressure flowing out of the manual control valve is less than the oil pressure flowing out of the brake electric proportional valve, the flow path switching device is used to connect the brake electric proportional valve to ports PX1 and PX2 of the brake main valve. The service brake system of the present invention can achieve both manual braking and brake-by-wire control.

Description

Technical Field

[0001] The present invention relates to the technical field of vehicle braking, and in particular to a service braking system. Background Art

[0002] Currently, open-pit mining relies primarily on manual labor. Cost, safety, and efficiency are major challenges hindering its continued development. The high cost of repetitive labor, the monotony of mechanical work, and the harsh working environment in mines are far from meeting the basic work requirements of the new generation of young people. Promoting high-quality development in the mining industry is an inevitable trend. "Mechanization to replace workers, automation to reduce manpower, and intelligent unmanned" will inevitably reduce labor costs and effectively improve corporate profitability. Furthermore, over 90% of coal mine accidents are caused by human error. Reduced or unmanned operations can effectively reduce or even prevent mine accidents. However, most mining vehicles currently rely on manual braking, which is inconvenient. Summary of the Invention

[0003] The problem solved by the present invention is how to realize manual braking and wire-controlled braking of a vehicle braking system.

[0004] To solve the above problems, the present invention provides a service brake system, comprising a main pump, a brake combination valve, a manual control valve, a flow path switching device, a brake electric proportional valve, a first service brake and a second service brake;

[0005] The P port of the brake combination valve is connected to the main pump, the BP1 port and BP2 port of the brake combination valve are connected to the P1 port and P2 port of the brake main valve respectively, the BPp port of the brake combination valve is connected to the P port of the manual control valve and the P port of the brake electric proportional valve respectively, and the T3 port of the brake combination valve is connected to the T port of the manual control valve and the T port of the brake electric proportional valve respectively;

[0006] The B1 port and the B2 port of the brake main valve are respectively connected to the first service brake and the second service brake;

[0007] The flow path switching device is respectively connected to the B port of the brake electric proportional valve, the B port of the manual control valve, and the PX1 port and PX2 port of the brake main valve;

[0008] When the oil pressure flowing out of the manual control valve is greater than the oil pressure flowing out of the brake electric proportional valve, the flow switching device is used to connect the B port of the brake electric proportional valve with the PX1 port and PX2 port of the brake main valve; when the oil pressure flowing out of the manual control valve is less than the oil pressure flowing out of the brake electric proportional valve, the flow switching device is used to connect the brake electric proportional valve with the PX1 port and PX2 port of the brake main valve.

[0009] Optionally, the flow path switching device is a brake shuttle valve block, the B port of the brake shuttle valve block is connected to the PX1 port and PX2 port of the brake main valve, and the B1 port and B2 port of the brake shuttle valve block are respectively connected to the B port of the brake electric proportional valve and the B port of the manual control valve.

[0010] Optionally, the brake shuttle valve block includes a wire-controlled brake pressure sensor, a manual brake pressure sensor, and a shuttle valve spool. The two inlet ends of the shuttle valve spool are respectively connected to the B port of the brake electric proportional valve and the B port of the manual control valve, and the outlet end of the shuttle valve spool is respectively connected to the PX1 port and PX2 port of the brake main valve. The artificial brake pressure sensor is arranged on the flow path between the shuttle valve spool and the manual control valve, and the wire-controlled brake pressure sensor is arranged on the flow path between the shuttle valve spool and the brake electric proportional valve.

[0011] Optionally, it also includes an automatic shuttle valve and an automatic brake pressure switch, the automatic brake pressure switch is respectively connected to the flow path between the P port and the BP1 port of the brake combination valve and the flow path between the P port and the BP2 port of the brake combination valve, the brake combination valve includes an automatic solenoid valve, the automatic brake pressure switch is electrically connected to the automatic solenoid valve, the two inlet ends of the automatic shuttle valve are respectively connected to the automatic solenoid valve and the B port of the brake shuttle valve block, and the outlet end of the automatic shuttle valve is respectively connected to the PX1 port and the PX2 port of the brake main valve.

[0012] Optionally, it also includes a loading brake shuttle valve, and the brake combination valve also includes a loading brake solenoid valve, the two inlet ends of the loading brake shuttle valve are respectively connected to the outlet ends of the loading brake solenoid valve and the automatic shuttle valve, and the outlet end of the loading brake shuttle valve is connected to the PX1 port of the brake main valve.

[0013] Optionally, a parking brake is further included, and the brake combination valve further includes a pressure reducing valve, a parking brake solenoid valve and a parking brake cut-off ball valve, and the pressure reducing valve, the parking brake solenoid valve, the parking brake cut-off ball valve and the parking brake are connected in sequence.

[0014] Optionally, it also includes a first accumulator and a second accumulator, and the brake combination valve also includes a rear brake accumulator discharge valve and a front brake accumulator discharge valve, the first accumulator is respectively connected to the front brake accumulator discharge valve and the P port and BP1 port of the brake combination valve, the second accumulator is respectively connected to the rear brake accumulator discharge valve and the P port and BP2 port of the brake combination valve, and the front brake accumulator discharge valve and the rear brake accumulator discharge valve are respectively used to communicate with the oil tank.

[0015] Optionally, an accumulator discharge back-pressure valve is further included, and the accumulator discharge back-pressure valve is arranged on the flow path between the front brake accumulator discharge valve and the oil tank and on the flow path between the rear brake accumulator discharge valve and the oil tank.

[0016] Optionally, a third accumulator is further included, and the third accumulator is connected to the P port of the brake combination valve.

[0017] Optionally, a low brake pressure alarm switch is further included, and the low brake pressure alarm switch is connected to the P port of the brake combination valve.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] The main pump delivers hydraulic oil to the brake combination valve. Since the BP1 port and BP2 port of the brake combination valve are connected to the P1 port and P2 port of the brake main valve respectively, the BPp port of the brake combination valve is connected to the P port of the manual control valve and the P port of the brake electric proportional valve respectively, and the T3 port of the brake combination valve is connected to the T port of the manual control valve and the T port of the brake electric proportional valve respectively, the brake combination valve can provide hydraulic oil for the brake main valve, the manual control valve and the brake electric proportional valve, and the manual control valve and the brake electric proportional valve are arranged in parallel; since the B1 port and B2 port of the brake main valve are connected to the first service brake and the second service brake respectively, the flow path switching device is connected to the B port of the brake electric proportional valve, the B port of the manual control valve and the When the PX1 port and PX2 port of the brake main valve are connected, the manual control valve and the brake electric proportional valve can realize pilot control of the brake main valve; when the oil pressure flowing out of the manual control valve is greater than the oil pressure flowing out of the brake electric proportional valve, the flow switching device is used to connect the B port of the brake electric proportional valve with the PX1 port and PX2 port of the brake main valve, realizing the braking of the first service brake and the second service brake; when the oil pressure flowing out of the manual control valve is less than the oil pressure flowing out of the brake electric proportional valve, the flow switching device is used to connect the brake electric proportional valve with the PX1 port and PX2 port of the brake main valve, realizing the braking of the first service brake and the second service brake, thereby realizing the manual braking and wire control braking of the service brake system of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 Schematic diagram of the flow path of an embodiment of the service brake system of the present invention;

[0021] Figure 2 Schematic diagram of an embodiment of the brake combination valve in the present invention.

[0022] Description of reference numerals:

[0023] 1. Brake combination valve; 2. Third accumulator; 3. Low brake pressure alarm switch; 4. Main pump; 5. Automatic brake pressure switch; 6. Parking brake; 7. Parking brake pressure switch; 8. Brake-by-wire pressure sensor; 9. Brake electric proportional valve; 10. Manual control valve; 11. Flow path switching device; 12. Manual brake pressure sensor; 13. Automatic shuttle valve; 14. First service brake; 15. Loading brake shuttle valve; 16. Brake main valve; 17. Second service brake; 18. Automatic solenoid valve; 19. Rear brake accumulator discharge valve; 20. Accumulator discharge back pressure valve; 21. Front brake accumulator discharge valve; 22. Pressure reducing valve; 23. Loading brake solenoid valve; 24. Parking brake stop ball valve; 25. Parking brake solenoid valve; 26. Base; 27. First accumulator; 28. Second accumulator. DETAILED DESCRIPTION

[0024] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0025] It should be noted that the terms "first," "second," and the like in the description and claims of the present invention and the accompanying drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or precedence. It should be understood that the terms used in this manner are interchangeable where appropriate, such that the embodiments of the present invention described herein can be practiced in an order other than that illustrated or described herein.

[0026] like Figure 1 、 2As shown, an embodiment of the present invention provides a service brake system, including a main pump 4, a brake combination valve 1, a manual control valve 10, a flow path switching device 11, a brake electric proportional valve 9, a first service brake 14 and a second service brake 17; the P port of the brake combination valve 1 is connected to the main pump 4, the BP1 port and the BP2 port of the brake combination valve 1 are connected to the P1 port and the P2 port of the brake main valve 16 respectively, the BPp port of the brake combination valve 1 is connected to the P port of the manual control valve 10 and the P port of the brake electric proportional valve 9 respectively, the T3 port of the brake combination valve 1 is connected to the T port of the manual control valve 10 and the T port of the brake electric proportional valve 9 respectively; the B1 port of the brake main valve 16 is connected to the T port of the manual control valve 10 and the T port of the brake electric proportional valve 9 respectively; The A and B2 ports are connected to the first service brake 14 and the second service brake 17 respectively; the flow switching device 11 is connected to the B port of the brake electric proportional valve 9, the B port of the manual control valve 10 and the PX1 port and PX2 port of the brake main valve 16 respectively; when the oil pressure flowing out of the manual control valve 10 is greater than the oil pressure flowing out of the brake electric proportional valve 9, the flow switching device 11 is used to connect the B port of the brake electric proportional valve 9 and the PX1 port and PX2 port of the brake main valve 16; when the oil pressure flowing out of the manual control valve 10 is less than the oil pressure flowing out of the brake electric proportional valve 9, the flow switching device 11 is used to connect the brake electric proportional valve 9 and the PX1 port and PX2 port of the brake main valve 16.

[0027] In this embodiment, the brake combination valve 1 is an integrated valve group, which includes a base 26 and various valve structures arranged on or in the base 26, such as Figure 2 As shown, the base 26 is provided with a P port, an A1 port, an AS1 port, an AS2 port, an AR1 port, an AF1 port, a BP1 port, a BP2 port, an SPX port, a T port, a T1 port, a T2 port, a T3 port, a BPp port, a LB port, a PB port, and the like.

[0028] In this embodiment, the manual control valve may be a pedal valve or a handle valve.

[0029] In this embodiment, the P port of the brake combination valve 1 is connected to the main pump 4, and the main pump 4 delivers hydraulic oil to the brake combination valve 1. Since the BP1 port and BP2 port of the brake combination valve 1 are respectively connected to the P1 port and P2 port of the brake main valve 16, the BPp port of the brake combination valve 1 is respectively connected to the P port of the manual control valve 10 and the P port of the brake electric proportional valve 9, and the T3 port of the brake combination valve 1 is respectively connected to the T port of the manual control valve 10 and the T port of the brake electric proportional valve 9, the brake combination valve 1 can provide hydraulic oil to the brake main valve 16, the manual control valve 10 and the brake electric proportional valve 9, and the manual control valve 10 and the brake electric proportional valve 9 are arranged in parallel.

[0030] In this embodiment, the B1 port and B2 port of the brake main valve 16 are respectively connected to the first service brake 14 and the second service brake 17, and the flow switching device 11 is respectively connected to the B port of the brake electric proportional valve 9, the B port of the manual control valve 10, and the PX1 port and PX2 port of the brake main valve 16, then the manual control valve 10 and the brake electric proportional valve 9 can realize pilot control of the brake main valve 16.

[0031] In this way, when the oil pressure flowing out of the manual control valve 10 is greater than the oil pressure flowing out of the brake electric proportional valve 9, the flow switching device 11 is used to connect the B port of the brake electric proportional valve 9 and the PX1 port and PX2 port of the brake main valve 16, thereby realizing the braking of the first service brake and the second service brake; when the oil pressure flowing out of the manual control valve 10 is less than the oil pressure flowing out of the brake electric proportional valve 9, the flow switching device 11 is used to connect the brake electric proportional valve 9 and the PX1 port and PX2 port of the brake main valve 16, thereby realizing the braking of the first service brake and the second service brake, thereby realizing the manual braking and wire control braking of the service brake system of the present invention.

[0032] Optionally, the flow path switching device 11 is a brake shuttle valve block, the B port of the brake shuttle valve block is connected to the PX1 port and PX2 port of the brake main valve 16, and the B1 port and B2 port of the brake shuttle valve block are respectively connected to the B port of the brake electric proportional valve 9 and the B port of the manual control valve 10.

[0033] Specifically, the brake shuttle valve block includes a wire-controlled brake pressure sensor 8, a manual brake pressure sensor 12, and a shuttle valve spool. The two inlet ends of the shuttle valve spool are respectively connected to the B port of the brake electric proportional valve 9 and the B port of the manual control valve 10, and the outlet end of the shuttle valve spool is respectively connected to the PX1 port and PX2 port of the brake main valve 16. The manual brake pressure sensor 12 is arranged on the flow path between the shuttle valve spool and the manual control valve 10, and the wire-controlled brake pressure sensor 8 is arranged on the flow path between the shuttle valve spool and the brake electric proportional valve 9.

[0034] In this embodiment, the brake shuttle valve block includes a first body, which is provided with a B port, a B1 port, a B2 port, an M1 port and an M2 port. The two inlet ends of the shuttle valve spool are respectively connected to the B port of the brake electric proportional valve 9 and the B port of the manual control valve 10 through the B1 port and the B2 port of the first body. The outlet end of the shuttle valve spool is respectively connected to the PX1 port and the PX2 port of the brake main valve 16 through the B port of the first body. The manual brake pressure sensor 12 is connected to the flow path between the shuttle valve spool and the manual control valve 10 through the M2 port on the first body for detecting the pressure of the flow path. The wire-controlled brake pressure sensor 8 is connected to the flow path between the shuttle valve spool and the brake electric proportional valve 9 through the M1 port on the first body for detecting the pressure of the flow path.

[0035] In this way, the flow rate of the brake electric proportional valve 9 can be controlled based on the data collected by the wire control brake pressure sensor 8, achieving closed-loop control for the unmanned driving stage. Based on the data collected by the manual brake pressure sensor 12, it is determined whether manual braking is involved in the unmanned driving stage.

[0036] In other embodiments, the flow path switching device 11 may also be a solenoid valve, through which the manual control valve 10 or the brake electric proportional valve 9 can pilot control the brake main valve 16 .

[0037] Optionally, it also includes an automatic shuttle valve 13 and an automatic brake pressure switch 5, the automatic brake pressure switch 5 is respectively connected to the flow path between the P port and the BP1 port of the brake combination valve 1 and the flow path between the P port and the BP2 port of the brake combination valve 1, the brake combination valve 1 includes an automatic solenoid valve 18, the automatic brake pressure switch 5 is electrically connected to the automatic solenoid valve 18, the two inlet ends of the automatic shuttle valve 13 are respectively connected to the automatic solenoid valve 18 and the B port of the brake shuttle valve block, and the outlet end of the automatic shuttle valve 13 is respectively connected to the PX1 port and the PX2 port of the brake main valve 16.

[0038] In this embodiment, the automatic brake pressure switch 5 is connected to the flow path between the P port and the BP1 port of the brake combination valve 1 and the flow path between the P port and the BP2 port of the brake combination valve 1 through the AS2 port of the base 26 of the brake combination valve 1, so as to detect the brake system pressure.

[0039] In this embodiment, the automatic brake pressure switch 5 is electrically connected to the automatic solenoid valve 18, and the automatic solenoid valve 18 is connected to one inlet end of the automatic shuttle valve 13 through the SPX port of the base 26 of the brake combination valve 1, and the other inlet end of the automatic shuttle valve 13 is connected to the B port of the brake shuttle valve block, and the outlet end of the automatic shuttle valve 13 is respectively connected to the PX1 port and the PX2 port of the brake main valve 16.

[0040] In this way, when the brake system pressure drops to the automatic brake engagement setting value, the automatic engagement pressure switch is activated, the automatic engagement solenoid valve 18 is energized, and the pressure is output to the PX1 port and PX2 port of the brake main valve 16. The brake main valve 16 is activated and the pressure is output to the first service brake and the second service brake, thereby achieving vehicle braking.

[0041] In this embodiment, when the driver discovers an emergency situation or the unmanned driving perception system sends an emergency braking command to the wire control system, the driver can press the emergency brake button or the wire control system can energize the automatic solenoid valve 18 and the vehicle will be put into emergency braking.

[0042] Furthermore, the system includes a low-brake-pressure alarm switch 3 , which is connected to the flow path between port P and port BP1, and between port P and port BP2, of the brake combination valve 1, respectively. The low-pressure alarm switch 3 is electrically connected to the onboard controller. Thus, when the brake system pressure drops below a set alarm value, the low-brake-pressure alarm switch 3 activates, and the cab instrument panel displays the low-brake-pressure indicator, alerting the driver.

[0043] Optionally, it also includes a loading brake shuttle valve 15, and the brake combination valve 1 also includes a loading brake solenoid valve 23. The two inlet ends of the loading brake shuttle valve 15 are respectively connected to the outlet ends of the loading brake solenoid valve 23 and the automatic shuttle valve 13, and the outlet end of the loading brake shuttle valve 15 is connected to the PX1 port of the brake main valve 16.

[0044] like Figure 1 、 2 As shown, the loading brake solenoid valve 23 is connected to one inlet end of the loading brake shuttle valve 15 through the LB port of the base 26 of the brake combination valve 1, the other inlet end of the loading brake shuttle valve 15 is connected to the outlet end of the automatic shuttle valve 13, and the outlet end of the loading brake shuttle valve 15 is connected to the PX1 port of the brake main valve 16.

[0045] In this embodiment, the loading brake solenoid valve 23 can be connected to a loading brake button, which is arranged in the cab. During the loading or unloading process of the vehicle, the driver presses the loading brake button or the wire control system issues a loading brake command. The loading brake solenoid valve 23 is energized, and the hydraulic oil passes through the loading brake shuttle valve 15 to the PX1 port of the brake main valve 16. The brake main valve 16 outputs hydraulic oil to the second service brake 17 (generally the rear brake of the vehicle) to achieve braking of the rear axle.

[0046] Optionally, a parking brake 6 is also included, and the brake combination valve 1 further includes a pressure reducing valve 22, a parking brake solenoid valve 25 and a parking brake stop ball valve 24. The pressure reducing valve 22, the parking brake solenoid valve 25, the parking brake stop ball valve 24 and the parking brake 6 are connected in sequence.

[0047] like Figure 1 、 2 As shown, the P port of the base 26 is connected to the pressure reducing valve 22, the parking brake solenoid valve 25, the parking brake stop ball valve 24 and the parking brake 6 in sequence. A parking brake release pressure switch 7 is also provided on the flow path between the parking brake stop ball valve 24 and the parking brake 6. The parking brake pressure switch is electrically connected to the parking brake stop ball valve 24 and the parking brake 6 respectively.

[0048] In this way, when the parking brake is applied, after the driver presses the parking brake button or the wire control system issues the parking brake, the parking brake solenoid valve 25 and the parking brake stop ball valve 24 lose power, stop supplying hydraulic oil to the parking brake 6, and the parking brake 6 is braked; when the parking brake is released, after the driver presses the release parking brake button or the wire control system issues the release parking brake, the parking brake solenoid valve 25 and the parking brake stop ball valve 24 are energized, and the pressure oil flows through the pressure reducing valve 22, the parking brake solenoid valve 25, and the parking brake stop ball valve 24 to the parking brake 6, and the parking brake is released.

[0049] Optionally, it also includes a first accumulator 27 and a second accumulator 28, and the brake combination valve 1 also includes a rear brake accumulator discharge valve 19 and a front brake accumulator discharge valve 21. The first accumulator 27 is respectively connected to the front brake accumulator discharge valve 21 and the P port and BP1 port of the brake combination valve 1, and the second accumulator 28 is respectively connected to the rear brake accumulator discharge valve 19 and the P port and BP2 port of the brake combination valve 1. The front brake accumulator discharge valve 21 and the rear brake accumulator discharge valve 19 are respectively used to communicate with the oil tank.

[0050] like Figure 1 、 2 As shown, the first accumulator 27 is connected to the rear brake accumulator discharge valve 19 and the P port and BP1 port of the brake combination valve 1 respectively through the AR1 port of the base 26 of the brake combination valve 1, and the second accumulator 28 is connected to the front brake accumulator discharge valve 21 and the P port and BP2 port of the brake combination valve 1 respectively through the AF1 port of the base 26 of the brake combination valve 1, and the front brake accumulator discharge valve 21 and the rear brake accumulator discharge valve 19 are connected to the oil tank respectively through the T1 port of the base 26 of the brake combination valve 1.

[0051] In this way, when the brake system fails and needs to be repaired, the pressure of the second accumulator 28 and the second accumulator 27 can be released by loosening the front brake accumulator discharge valve 21 and the rear brake accumulator discharge valve 19, thereby avoiding the danger caused by high-pressure oil during the repair process.

[0052] Optionally, an accumulator discharge back-pressure valve 20 is further included, which is provided on the flow path between the front brake accumulator discharge valve 21 and the oil tank and on the flow path between the rear brake accumulator discharge valve 19 and the oil tank.

[0053] like Figure 1 、 2 As shown, the accumulator discharge back-pressure valve 20 is installed in the flow path between port T1 of the base 26 of the brake combination valve 1 and the oil tank, and vice versa. The accumulator discharge back-pressure valve 20 is a one-way valve. The back pressure of the one-way valve spring ensures that the accumulator retains an oil pressure equivalent to that of the one-way valve spring, preventing the hydraulic oil in the brake system from being completely drained, which could cause a delayed brake response.

[0054] Optionally, a third accumulator 2 is further included, and the third accumulator 2 is communicated with the P port of the brake combination valve 1 .

[0055] like Figure 1 、 2 As shown, the third accumulator 2 is connected to the P port of the base 26 of the brake combination valve 1 through the A1 port of the base 26 of the brake combination valve 1. The third accumulator 2 ensures that multiple brake oil volumes can be provided when the engine is turned off, thereby avoiding brake failure caused by engine stall.

[0056] The reader should understand that in the description of this specification, reference to the terms "one embodiment", "some embodiments", "examples", "specific examples" or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, different embodiments or examples described in this specification and features of different embodiments or examples can be combined and combined by those skilled in the art without contradiction.

[0057] Although the present disclosure is disclosed as above, the protection scope of the present disclosure is not limited thereto. Those skilled in the art may make various changes and modifications without departing from the spirit and scope of the present disclosure, and these changes and modifications will fall within the protection scope of the present invention.

Claims

1. A service brake system, characterized in that: It includes a main pump (4), a brake combination valve (1), a manual control valve (10), a flow path switching device (11), a brake electric proportional valve (9), a first service brake (14) and a second service brake (17); The P port of the brake combination valve (1) is communicated with the main pump (4), the BP1 port and the BP2 port of the brake combination valve (1) are communicated with the P1 port and the P2 port of the brake main valve (16) respectively, the BPp port of the brake combination valve (1) is communicated with the P port of the manual control valve (10) and the P port of the brake electric proportional valve (9) respectively, and the T3 port of the brake combination valve (1) is communicated with the T port of the manual control valve (10) and the T port of the brake electric proportional valve (9) respectively; The B1 port and the B2 port of the brake main valve (16) are respectively connected to the first service brake (14) and the second service brake (17); The flow path switching device (11) is respectively connected to the B port of the brake electric proportional valve (9), the B port of the manual control valve (10), and the PX1 port and the PX2 port of the brake main valve (16); the flow path switching device (11) is a brake shuttle valve block, the B port of the brake shuttle valve block is connected to the PX1 port and the PX2 port of the brake main valve (16), and the B1 port and the B2 port of the brake shuttle valve block are respectively connected to the B port of the brake electric proportional valve (9) and the B port of the manual control valve (10); It also includes an automatic shuttle valve (13) and an automatic brake pressure switch (5), the automatic brake pressure switch (5) being in communication with the flow path between the P port and the BP1 port of the brake combination valve (1) and the flow path between the P port and the BP2 port of the brake combination valve (1), the brake combination valve (1) including an automatic solenoid valve (18), the automatic brake pressure switch (5) being electrically connected to the automatic solenoid valve (18), the two inlet ends of the automatic shuttle valve (13) being in communication with the automatic solenoid valve (18) and the B port of the brake shuttle valve block, and the outlet end of the automatic shuttle valve (13) being in communication with the PX1 port and the PX2 port of the brake main valve (16). When the oil pressure flowing out of the manual control valve (10) is greater than the oil pressure flowing out of the brake electric proportional valve (9), the flow path switching device (11) is used to conduct the B port of the brake electric proportional valve (9) with the PX1 port and the PX2 port of the brake main valve (16); when the oil pressure flowing out of the manual control valve (10) is less than the oil pressure flowing out of the brake electric proportional valve (9), the flow path switching device (11) is used to conduct the brake electric proportional valve (9) with the PX1 port and the PX2 port of the brake main valve (16).

2. The service brake system according to claim 1, characterized in that: The brake shuttle valve block comprises a wire-controlled brake pressure sensor (8), an artificial brake pressure sensor (12), and a shuttle valve core. The two inlet ends of the shuttle valve core are respectively connected to the B port of the brake electric proportional valve (9) and the B port of the artificial control valve (10), and the outlet end of the shuttle valve core is respectively connected to the PX1 port and the PX2 port of the brake main valve (16). The artificial brake pressure sensor (12) is arranged on the flow path between the shuttle valve core and the artificial control valve (10), and the wire-controlled brake pressure sensor (8) is arranged on the flow path between the shuttle valve core and the brake electric proportional valve (9).

3. The service brake system according to claim 1, characterized in that: The brake combination valve (1) further comprises a loading brake shuttle valve (15), and the loading brake solenoid valve (23) is further comprised. The two inlet ends of the loading brake shuttle valve (15) are respectively connected to the loading brake solenoid valve (23) and the outlet end of the automatic shuttle valve (13), and the outlet end of the loading brake shuttle valve (15) is connected to the PX1 port of the brake main valve (16).

4. The service brake system according to claim 3, characterized in that: The invention also includes a parking brake (6), and the brake combination valve (1) further includes a pressure reducing valve (22), a parking brake solenoid valve (25) and a parking brake stop ball valve (24), and the pressure reducing valve (22), the parking brake solenoid valve (25), the parking brake stop ball valve (24) and the parking brake (6) are connected in sequence.

5. The service brake system according to claim 1, characterized in that: The brake combination valve (1) further comprises a first accumulator (27) and a second accumulator (28); the brake combination valve (1) further comprises a rear brake accumulator discharge valve (19) and a front brake accumulator discharge valve (21); the first accumulator (27) is respectively connected to the front brake accumulator discharge valve (21) and the P port and BP1 port of the brake combination valve (1); the second accumulator (28) is respectively connected to the rear brake accumulator discharge valve (19) and the P port and BP2 port of the brake combination valve (1); the front brake accumulator discharge valve (21) and the rear brake accumulator discharge valve (19) are respectively used to communicate with the oil tank.

6. The service brake system according to claim 5, characterized in that: It also includes an accumulator discharge back pressure valve (20), which is arranged on the flow path between the front brake accumulator discharge valve (21) and the oil tank and on the flow path between the rear brake accumulator discharge valve (19) and the oil tank.

7. The service brake system according to claim 1, characterized in that: It also includes a third accumulator (2), which is connected to the P port of the brake combination valve (1).

8. The service brake system according to claim 1, characterized in that: It also includes a low brake pressure alarm switch (3), which is connected to the P port of the brake combination valve (1).

Images