Air braking system and method and engineering machinery

Abstract

The invention discloses an air braking system, an air braking method and engineering machinery in the technical field of engineering machinery, and aims to solve the problems that in the prior art, an electric control device is generally adopted for achieving braking work, and an electric control system is complex in structure, high in cost, insufficient in system reliability and the like. The system comprises a first air storage cylinder, a second air storage cylinder, a hand brake valve and a differential relay valve, the output end of the first air storage cylinder and the output end of the second air storage cylinder are both connected with the input end of a two-way one-way valve, and the output end of the two-way one-way valve is connected with the input end of the hand brake valve; when the second relay valve fails, the parking braking efficiency of the rear axle can be fully utilized, and the driving safety is improved; when a loop fails after braking, parking braking of a rear axle can be automatically implemented after a driver steps on a brake pedal, and extra operation is not needed; different from an electric control device in the prior art, an existing braking mode does not need to be changed, the principle is simple, the system is reliable, and meanwhile cost is low.

Description

Technical Field

[0001] The present invention relates to a pneumatic braking system, method and construction machinery, belonging to the technical field of construction machinery. Background Art

[0002] At present, the service brake (foot brake) of truck cranes adopts a dual-circuit pneumatic braking system. This system requires that when one circuit fails (is damaged and leaks air), the other circuit can still work independently to ensure normal braking of the vehicle. However, in actual use, if one circuit of the service braking system fails, the braking performance of the vehicle is often low, especially for odd-axis vehicles. For example, when the braking systems of the rear two axles of a three-axle vehicle fail, only one axle's braking works, but the braking distance is too long, and the driver cannot handle emergencies, and serious traffic accidents may occur with a slight carelessness.

[0003] When the braking system of the front axle or rear axle in the prior art fails, such as a pneumatic braking parking circuit system in CN111791859A, an electronic control device is usually used to achieve braking work. The electronic control system has problems such as complex structure, high cost, and insufficient system reliability. When the sensor fails, it is easy to pose a hidden danger to driving safety; while the non-electronic pneumatic braking system usually does not consider the situation of braking system failure, and the safety hidden danger is relatively high. Summary of the Invention

[0004] The purpose of the present invention is to overcome the deficiencies in the prior art and provide a pneumatic braking system, method and construction machinery. When the second relay valve fails, the parking braking efficiency of the rear axle can be fully utilized, increasing the braking torque of the whole vehicle and improving driving safety; when the rear circuit fails, the parking brake of the rear axle can be automatically implemented after the driver steps on the brake pedal without additional operation, which is simple and convenient; when the parking air storage tank fails, the first air storage tank and the second air storage tank can automatically replenish air to the parking cavity of the second air chamber, preventing sudden braking of the vehicle during driving and ensuring the safety of the vehicle. Different from the electronic control device in the prior art, the present invention does not need to change the existing braking form, has a simple principle, a reliable system, and a relatively low cost, and has good economy.

[0005] To solve the above technical problems, the present invention is implemented by the following technical solutions: In a first aspect, the present invention provides a pneumatic braking system, comprising a first air reservoir, a second air reservoir, a hand brake valve, and a differential relay valve. The output ends of the first air reservoir and the second air reservoir are both connected to the input end of a two-way one-way valve, the output end of the two-way one-way valve is connected to the input end of the hand brake valve, the output end of the first air reservoir is connected to the input end of a first relay valve, the output end of the second air reservoir is connected to the input end of a second relay valve, the output end of the first relay valve is connected to the service chamber of a first air chamber, the output end of the second relay valve is connected to the service chamber of a second air chamber, a first output end of a foot brake valve is connected to the first relay valve, a second output end of the foot brake valve is connected to the second relay valve, the input end of the first air reservoir is connected to a first input end of the foot brake valve, and the input end of the second air reservoir is connected to a second input end of the foot brake valve; A first input end of the differential relay valve is connected to a parking air reservoir, the parking air reservoir is connected to the input end of the hand brake valve, the output end of the hand brake valve is connected to a second input end of the differential relay valve, a third input end of the differential relay valve is connected to the parking chamber of the second air chamber, a fourth input end of the differential relay valve is connected to the output end of the first relay valve, and a fifth input end of the differential relay valve is connected to the output end of the second relay valve.

[0006] Furthermore, a four-way circuit is further included. A first output end of the four-way circuit is connected to the input end of the first air reservoir, a second output end of the four-way circuit is connected to the input end of the second air reservoir, a third output end of the four-way circuit is connected to the parking air reservoir, and the input end of the four-way circuit is connected to an air compressor.

[0007] Furthermore, a dryer is provided between the input end of the four-way circuit and the air compressor.

[0008] Furthermore, the differential relay valve includes a communication valve and a variable cross-section valve core. The first input end and the second input end of the differential relay valve are both connected to a first end of the communication valve through one-way valves, a third input end of the differential relay valve is connected to a second end of the communication valve, an exhaust port is provided on the communication valve, a movable valve core is movably connected inside the communication valve, the movable valve core is elastically connected to the communication valve through a spring, the second end of the communication valve is connected to the exhaust port or the first end of the communication valve through the movable valve core, a piston rod is movably connected inside the variable cross-section valve core, the piston rod is fixedly connected to the movable valve core, a second input end of the differential relay valve is connected to a first input end of a shuttle valve, the output end of the shuttle valve is connected to the communication valve, a second input end of the shuttle valve is connected to the rod chamber of the variable cross-section valve core, a fifth input end of the differential relay valve is connected to the rod chamber of the variable cross-section valve core, and a fourth input end of the differential relay valve is connected to the rodless chamber of the variable cross-section valve core.

[0009] In a second aspect, the present invention provides a pneumatic braking method, based on the pneumatic braking system described in the first aspect, including the following steps: Obtain the states of the hand brake valve and the foot brake valve, and trigger the differential relay valve to work according to the states of the hand brake valve and the foot brake valve to achieve braking; Among them, the states of the hand brake valve include working and deactivated, and the states of the foot brake valve include working and deactivated.

[0010] Further, the triggering of the differential relay valve to work according to the states of the hand brake valve and the foot brake valve to achieve braking specifically includes: When the state of the hand brake valve is working and the state of the foot brake valve is deactivated, the first input end of the differential relay valve is ventilated, the second input end, the fourth output end and the fifth output end are de-ventilated, the first relay valve and the second relay valve are not ventilated, and the movable valve core connects the second end of the connecting valve to the exhaust port, and the parking chamber of the second air chamber deflates to achieve parking braking; When the state of the hand brake valve is working and the state of the foot brake valve is working, the first input end, the fourth output end and the fifth output end of the differential relay valve are ventilated, the second input end is de-ventilated, the movable valve core connects the second end of the connecting valve to the first end, the parking air storage cylinder supplies air to the parking chamber of the second air chamber through the differential relay valve, the parking braking is released, the first relay valve and the second relay valve are ventilated, the first air storage cylinder supplies air to the service chamber of the first air chamber through the first relay valve, and the second air storage cylinder supplies air to the service chamber of the second air chamber through the second relay valve to achieve service braking.

[0011] Further, the triggering of the differential relay valve to work according to the states of the hand brake valve and the foot brake valve to achieve braking further includes: When the state of the hand brake valve is deactivated and the state of the foot brake valve is deactivated, the first input end and the second input end of the differential relay valve are ventilated, the fourth output end and the fifth output end are de-ventilated, the first relay valve and the second relay valve are not ventilated, the movable valve core connects the first end of the connecting valve to the second end, the parking air storage cylinder supplies air to the parking chamber of the second air chamber through the differential relay valve, the parking braking is released, and no braking work is performed; When the state of the hand brake valve is deactivated and the state of the foot brake valve is working, the first input end, the second input end, the fourth output end and the fifth output end of the differential relay valve are ventilated, the first relay valve and the second relay valve are ventilated, the movable valve core connects the second end of the connecting valve to the first end, the parking air storage cylinder supplies air to the parking chamber of the second air chamber through the differential relay valve, the parking braking is released, the first air storage cylinder supplies air to the service chamber of the first air chamber through the first relay valve, and the second air storage cylinder supplies air to the service chamber of the second air chamber through the second relay valve to achieve service braking.

[0012] Further, triggering the differential relay valve to work according to the states of the hand brake valve and the foot brake valve to achieve braking further includes: When the state of the hand brake valve is deactivated, the state of the foot brake valve is working, and the first relay valve fails, the first input end, the second input end, and the fifth output end of the differential relay valve are ventilated, the fourth output end is cut off from the air supply, the second relay valve is ventilated, and the movable valve core connects the second end of the communication valve to the first end. The parking air storage tank supplies air to the parking chamber of the second air chamber through the differential relay valve, the parking brake is released, and the second air storage tank supplies air to the service chamber of the second air chamber through the second relay valve to achieve service braking.

[0013] Further, triggering the differential relay valve to work according to the states of the hand brake valve and the foot brake valve to achieve braking further includes: When the state of the hand brake valve is deactivated, the state of the foot brake valve is working, and the second relay valve fails, the first input end, the second input end, and the fourth output end of the differential relay valve are ventilated, the fifth output end is cut off from the air supply, the first relay valve is ventilated, and the movable valve core connects the second end of the communication valve to the exhaust port. The parking chamber of the second air chamber discharges air, and the first air storage tank supplies air to the service chamber of the first air chamber through a relay valve to achieve service braking and parking braking.

[0014] In a third aspect, the present invention provides a construction machinery including the pneumatic braking system described in the first aspect.

[0015] Compared with the prior art, the beneficial effects achieved by the present invention are as follows: When the second relay valve fails in the present invention, the parking braking efficiency of the rear axle can be fully utilized, the braking torque of the whole vehicle is increased, and the driving safety is improved; when the rear braking circuit fails, the parking brake of the rear axle can be automatically implemented after the driver steps on the brake pedal without additional operation, which is simple and convenient; when the parking air storage tank fails, the first air storage tank and the second air storage tank can automatically replenish air to the parking chamber of the second air chamber to prevent the vehicle from suddenly braking during driving and ensure the safety of the vehicle; at the same time, the present invention can avoid the service chamber and the parking chamber of the second air chamber acting on the brake at the same time to avoid damage to the brake; different from the existing electronic control device in the prior art, the present invention does not need to change the existing braking form, has a simple principle, a reliable system, and a low cost, and has good economy. Description of the Drawings

[0016] Figure 1 is a schematic structural diagram of a pneumatic braking system according to an embodiment of the present invention; Figure 2 is a schematic structural diagram of a differential relay valve according to an embodiment of the present invention.

[0017] In the figure: 1, air compressor; 2, dryer; 3, four-circuit; 4, first air storage tank; 5, second air storage tank; 6, hand brake valve; 7, foot brake valve; 8, parking air storage tank; 9, second relay valve; 10, first relay valve; 11, differential relay valve; 111, shuttle valve; 112, movable spool; 113, variable cross-section spool; 114, piston rod; 115, connecting valve; 12, first air chamber; 13, second air chamber. Specific embodiments

[0018] The present invention will be further described below with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and cannot be used to limit the protection scope of the present invention.

[0019] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation of the present invention. In addition, the terms "first", "second", etc. are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the quantity of the indicated technical features. Thus, the features defined with "first", "second", etc. may explicitly or implicitly include one or more of such features. In the description of the present invention, unless otherwise specified, the meaning of "a plurality" is two or more.

[0020] In the description of the present invention, it should be noted that unless otherwise clearly specified and limited, the terms "installed", "connected", "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood through specific situations. Embodiment 1:

[0021] As Figure 1 and Figure 2As shown in the figure, the present invention provides a pneumatic braking system, which includes a first air reservoir 4, a second air reservoir 5, a hand brake valve 6, and a differential relay valve 11. The output ends of the first air reservoir 4 and the second air reservoir 5 are both connected to the input end of a two-way one-way valve. The output end of the two-way one-way valve is connected to the input end of the hand brake valve 6. The output end of the first air reservoir 4 is connected to the input end of a first relay valve 10. The output end of the second air reservoir 5 is connected to the input end of a second relay valve 9. The output end of the first relay valve 10 is connected to the service chamber of a first air chamber 12. The output end of the second relay valve 9 is connected to the service chamber of a second air chamber 13. The first output end of a foot brake valve 7 is connected to the first relay valve 10, and the second output end of the foot brake valve 7 is connected to the second relay valve 9. The input end of the first air reservoir 4 is connected to the first input end of the foot brake valve 7, and the input end of the second air reservoir 5 is connected to the second input end of the foot brake valve 7; The first input end of the differential relay valve 11 is connected to a parking air reservoir 8. The parking air reservoir 8 is connected to the input end of the hand brake valve 6. The output end of the hand brake valve 6 is connected to the second input end of the differential relay valve 11. The third input end of the differential relay valve 11 is connected to the parking chamber of the second air chamber 13. The fourth input end of the differential relay valve 11 is connected to the output end of the first relay valve 10. The fifth input end of the differential relay valve 11 is connected to the output end of the second relay valve 9.

[0022] Specifically, A in the figure is the first input end of the differential relay valve 11; B is the second input end of the differential relay valve 11; C is the third input end of the differential relay valve 11; D is the fourth input end of the differential relay valve 11; E is the fifth input end of the differential relay valve 11. The first air chamber 12 is used for front axle braking, and the second air chamber 13 is used for rear axle braking. When the foot brake valve 7 works, its first output end is communicated with the first input end, and the second output end is communicated with the second input end. The relevant components for controlling front axle braking are the front brake circuit, and the relevant components for controlling rear axle braking are the rear brake circuit.

[0023] As Figure 2As shown, in one embodiment, the differential relay valve 11 includes a communication valve 115 and a variable cross-section valve core 113. The first input end and the second input end of the differential relay valve 11 are both connected to the first end of the communication valve 115 through check valves. The third input end of the differential relay valve 11 is connected to the second end of the communication valve 115. An exhaust port is provided on the communication valve 115. An active valve core 112 is movably connected inside the communication valve 115. The active valve core 112 is elastically connected to the communication valve 115 through a spring (not shown in the figure). The second end of the communication valve 115 is connected to the exhaust port or the first end of the communication valve 115 through the active valve core 112. A piston rod 114 is movably connected inside the variable cross-section valve core 113. The piston rod 114 is fixedly connected to the active valve core 112. The second input end of the differential relay valve 11 is connected to the first input end of a shuttle valve 111. The output end of the shuttle valve 111 is connected to the communication valve 115. The second input end of the shuttle valve 111 is connected to the rod chamber of the variable cross-section valve core 113. The fifth input end of the differential relay valve 11 is connected to the rod chamber of the variable cross-section valve core 113. The fourth input end of the differential relay valve 11 is connected to the rodless chamber of the variable cross-section valve core 113.

[0024] Specifically, the piston rod 114 is fixedly connected to the active valve core 112. Port A and port B of the differential relay valve 11 are connected to the first end of the communication valve 115 through check valves.

[0025] During operation, when the staff pulls up the handbrake and does not step on the brake pedal, at this time the handbrake valve 6 is in the working state, the foot brake valve 7 is in the deactivated state, the first relay valve 10 and the second relay valve 9 cut off the air supply. Ports B, D, and E of the differential relay valve 11 cut off the air supply. At this time, the active valve core 112 is reset upward through the spring. The second end of the communication valve 115 is connected to the exhaust port, thereby connecting port C to the exhaust port. The parking chamber of the second air chamber 13 discharges air. Under the action of the spring in the parking chamber, the rear axle realizes parking braking.

[0026] When the staff releases the handbrake and does not step on the brake pedal, at this time the handbrake valve 6 is in the deactivated state, the foot brake valve 7 is in the deactivated state, the first relay valve 10 and the second relay valve 9 cut off the air supply. Port B of the differential relay valve 11 is ventilated, ports D and E cut off the air supply. The high-pressure gas in port B pushes the active valve core 112 downward through the shuttle valve 111. The first end and the second end of the communication valve 115 are connected, so that the active valve core 112 connects port C to port A. The parking air storage tank 8 now inflates the parking chamber of the second air chamber 13 through the differential relay valve 11. The parking brake is released, and at this time the vehicle does not perform braking work.

[0027] When the staff member releases the parking brake and depresses the brake pedal, the hand brake valve 6 is in the deactivated state and the foot brake valve 7 is in the working state. The foot brake valve 7 controls the first relay valve 10 and the second relay valve 9 to let air in. Ports B, D, and E of the differential relay valve 11 let air in. At this time, the sum of the pressure from the shuttle valve 111 and the pressure in the rod chamber of the variable cross-section spool 113 is greater than the pressure in the non-rod chamber of the variable cross-section spool 113, thus pushing the movable spool 112 to move downward, making the movable spool 112 connect port C with port A. The parking air storage tank 8 then inflates the parking chamber of the second air chamber 13 through the differential relay valve 11, and the parking is in the released state. At this time, the first air storage tank 4 inflates the service chamber of the first air chamber 12 through the first relay valve 10, and the front axle achieves service braking. The second air storage tank 5 inflates the service chamber of the second air chamber 13 through the second relay valve 9, and the front and rear axles achieve service braking.

[0028] When the staff member pulls up the parking brake and depresses the brake pedal, the hand brake valve 6 is in the working state and the foot brake valve 7 is in the working state. The foot brake valve 7 controls the first relay valve 10 and the second relay valve 9 to let air in. Port B of the differential relay valve 11 cuts off the air supply, and ports D and E let air in. At this time, the sum of the pressure from the shuttle valve 111 and the pressure in the rod chamber of the variable cross-section spool 113 is greater than the pressure in the non-rod chamber of the variable cross-section spool 113, thus pushing the movable spool 112 to move downward, making the movable spool 112 connect port C with port A. The parking air storage tank 8 then inflates the parking chamber of the second air chamber 13 through the differential relay valve 11, and the parking is in the released state. At this time, the first air storage tank 4 inflates the service chamber of the first air chamber 12 through the first relay valve 10, and the front axle achieves service braking. The second air storage tank 5 inflates the service chamber of the second air chamber 13 through the second relay valve 9, and the rear axle achieves service braking, thus avoiding damage to the brake caused by the simultaneous action of service braking and parking braking and ensuring the safety of the system.

[0029] When the staff member releases the parking brake, the first relay valve 10 fails, and the staff member depresses the brake pedal, the hand brake valve 6 is in the deactivated state and the foot brake valve 7 is in the working state. The foot brake valve 7 controls the second relay valve 9 to let air in. The first relay valve 10 cuts off the air supply due to failure. Ports B and E of the differential relay valve 11 let air in, and port D cuts off the air supply. At this time, the pressure of the shuttle valve 111 and the pressure in the rod chamber of the variable cross-section spool 113 push the movable spool 112 to move downward, making the movable spool 112 connect port C with port A. The parking air storage tank 8 then inflates the parking chamber of the second air chamber 13 through the differential relay valve 11, and the parking is in the released state. At this time, the second air storage tank 5 inflates the service chamber of the second air chamber 13 through the second relay valve 9, and the rear axle achieves service braking.

[0030] When the staff member releases the parking brake, the second relay valve 9 fails, and the brake pedal is depressed. At this time, the hand brake valve 6 is in the disabled state, and the foot brake valve 7 is in the working state. The foot brake valve 7 controls the first relay valve 10 to admit air. Since the second relay valve 9 fails and cuts off the air supply, the B port and D port of the differential relay valve 11 are ventilated, and the E port cuts off the air supply. At this time, the pressure in the rodless chamber of the variable cross-section spool 113 is greater than the pressure of the shuttle valve 111, thus pushing the movable spool 112 to move upward, causing the movable spool 112 to connect the C port with the exhaust port. The parking chamber of the second air chamber 13 deflates. Under the action of the parking chamber spring, the rear axle realizes parking braking. At this time, the first air storage tank 4 inflates the service chamber of the first air chamber 12 through the first relay valve 10, and the front axle realizes service braking. Through the cooperation of the parking braking of the rear axle and the service braking of the front axle, the braking force of the vehicle is increased, and the braking effect is improved.

[0031] The present invention makes full use of the parking function of the rear axle and can use parking for braking after the second relay valve 9 fails; since the front axle of the braking system usually has no parking function, when the first relay valve 10 fails, the differential relay valve 11 does not perform additional actions because there is no parking available.

[0032] During the driving process of the vehicle, if the parking air storage tank 8 fails, at this time, the A port of the differential relay valve 11 cuts off the air supply. Since the first relay valve 10 and the second relay valve 9 work normally, the first relay valve 10 and the second relay valve 9 can supply air to the hand brake valve 6 through the double-check one-way valve, thus supplying air to the first end of the communication valve 115 through the B port of the differential relay valve 11 and the one-way valve. When the vehicle is driving normally, the first end and the second end of the communication valve 115 are connected, that is, air is supplied to the C port through the B port of the differential relay valve 11 to supply air to the parking chamber of the second air chamber 13, avoiding the danger of the vehicle suddenly braking and causing traffic jams or even serious traffic accidents, and improving driving safety.

[0033] When the rear braking circuit fails (that is, the second relay valve 9 fails) in the present invention, the parking braking efficiency of the rear axle can be fully utilized, the braking torque of the whole vehicle is increased, and driving safety is improved; and when the rear braking circuit fails, the parking braking of the rear axle can be automatically implemented after the driver depresses the brake pedal without additional operation, which is simple and convenient; when the parking air storage tank 8 fails, the first air storage tank 4 and the second air storage tank 5 can automatically replenish air to the parking chamber of the second air chamber 13, preventing the vehicle from suddenly braking during the driving process and ensuring the safety of the vehicle; at the same time, the present invention can avoid the service chamber and the parking chamber of the second air chamber 13 acting on the brake at the same time, avoiding damage to the brake.

[0034] The pneumatic braking system of the present invention is different from the existing electronic control devices. It does not need to change the existing braking form, has a simple principle, a reliable system, and at the same time has a relatively low cost, showing good economy. It can effectively improve the remaining braking efficiency of a single circuit and balance the braking force of each axle.

[0035] An embodiment further includes a four-way circuit 3. The first output end of the four-way circuit 3 is connected to the input end of the first air storage tank 4, the second output end of the four-way circuit 3 is connected to the input end of the second air storage tank 5, the third output end of the four-way circuit 3 is connected to the parking air storage tank 8, and the input end of the four-way circuit 3 is connected to the air compressor 1. A dryer 2 is provided between the input end of the four-way circuit 3 and the air compressor 1.

[0036] Specifically, the air compressor 1 inflates the first air storage tank 4 through the first output end of the four-way circuit 3, inflates the second air storage tank 5 through the second output end of the four-way circuit 3, and inflates the parking air storage tank 8 through the third output end. The dryer 2 is used to dry the air, ensuring the stability of each structure during operation. Embodiment Two:

[0037] The present invention provides a pneumatic braking method based on the pneumatic braking system described in Embodiment One, including the following steps: Obtain the states of the hand brake valve 6 and the foot brake valve 7, and trigger the differential relay valve 11 to work according to the states of the hand brake valve 6 and the foot brake valve 7 to achieve braking operation; Among them, the states of the hand brake valve 6 include working and deactivation, and the states of the foot brake valve 7 include working and deactivation.

[0038] In an embodiment, triggering the differential relay valve 11 to work according to the states of the hand brake valve 6 and the foot brake valve 7 to achieve braking operation specifically includes: When the state of the hand brake valve 6 is working and the state of the foot brake valve 7 is deactivated, the first input end of the differential relay valve 11 is ventilated, the second input end, the fourth output end, and the fifth output end are cut off from the air, the first relay valve 10 and the second relay valve 9 are not ventilated, and the movable valve core 112 connects the second end of the connecting valve 115 to the exhaust port, and the parking chamber of the second air chamber 13 releases air to achieve parking braking; When the hand brake valve 6 is in the working state and the foot brake valve 7 is in the working state, the first input end, the fourth output end and the fifth output end of the differential relay valve 11 are ventilated, the second input end is cut off from the air, the movable valve core 112 connects the second end of the connecting valve 115 to the first end, and the parking air storage cylinder 8 supplies air to the parking cavity of the second air chamber 13 through the differential relay valve 11, the parking brake is released, the first relay valve 10 and the second relay valve 9 are ventilated, the first air storage cylinder 4 supplies air to the service cavity of the first air chamber 12 through the first relay valve 10, and the second air storage cylinder 5 supplies air to the service cavity of the second air chamber 13 through the second relay valve 9 to realize service braking.

[0039] An embodiment, triggering the differential relay valve 11 to work according to the states of the hand brake valve 6 and the foot brake valve 7 to realize braking work, further includes: When the hand brake valve 6 is in the deactivated state and the foot brake valve 7 is in the deactivated state, the first input end and the second input end of the differential relay valve 11 are ventilated, the fourth output end and the fifth output end are cut off from the air, the first relay valve 10 and the second relay valve 9 are not ventilated, the movable valve core 112 connects the first end of the connecting valve 115 to the second end, and the parking air storage cylinder 8 supplies air to the parking cavity of the second air chamber 13 through the differential relay valve 11, the parking brake is released, and no braking work is performed; When the hand brake valve 6 is in the deactivated state and the foot brake valve 7 is in the working state, the first input end, the second input end, the fourth output end and the fifth output end of the differential relay valve 11 are ventilated, the first relay valve 10 and the second relay valve 9 are ventilated, the movable valve core 112 connects the second end of the connecting valve 115 to the first end, and the parking air storage cylinder 8 supplies air to the parking cavity of the second air chamber 13 through the differential relay valve 11, the parking brake is released, the first air storage cylinder 4 supplies air to the service cavity of the first air chamber 12 through the first relay valve 10, and the second air storage cylinder 5 supplies air to the service cavity of the second air chamber 13 through the second relay valve 9 to realize service braking.

[0040] An embodiment, triggering the differential relay valve 11 to work according to the states of the hand brake valve 6 and the foot brake valve 7 to realize braking work, further includes: When the hand brake valve 6 is in the deactivated state, the foot brake valve 7 is in the working state, and the first relay valve 10 fails, the first input end, the second input end and the fifth output end of the differential relay valve 11 are ventilated, the fourth output end is cut off from the air, the second relay valve 9 is ventilated, the movable valve core 112 connects the second end of the connecting valve 115 to the first end, and the parking air storage cylinder 8 supplies air to the parking cavity of the second air chamber 13 through the differential relay valve 11, the parking brake is released, and the second air storage cylinder 5 supplies air to the service cavity of the second air chamber 13 through the second relay valve 9 to realize service braking.

[0041] An embodiment, which triggers the differential relay valve 11 to work according to the states of the hand brake valve 6 and the foot brake valve 7 to achieve braking operation, further includes: When the state of the hand brake valve 6 is deactivated, the state of the foot brake valve 7 is working, and the second relay valve 9 fails, the first input end, the second input end and the fourth output end of the differential relay valve 11 are ventilated, the fifth output end is cut off from the air supply, the first relay valve 10 is ventilated, the movable valve core 112 connects the second end of the connecting valve 115 with the exhaust port, the parking chamber of the second air chamber 13 discharges air, and the first air storage cylinder 4 supplies air to the service chamber of the first air chamber 12 through a relay valve, so as to achieve front-loop service braking and rear-loop parking braking. Embodiment Three:

[0042] The present invention provides a construction machinery, including the pneumatic braking system described in Embodiment One.

[0043] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the technical principle of the present invention, several improvements and deformations can be made, and these improvements and deformations should also be regarded as the protection scope of the present invention.

Claims

1. A pneumatic brake system, characterized in that: It comprises a first air reservoir, a second air reservoir, a hand brake valve and a differential relay valve, wherein the output ends of the first air reservoir and the second air reservoir are both connected to the input end of the two-way one-way valve, the output end of the two-way one-way valve is connected to the input end of the hand brake valve, the output end of the first air reservoir is connected to the input end of the first relay valve, the output end of the second air reservoir is connected to the input end of the second relay valve, the output end of the first relay valve is connected to the driving cavity of the first air chamber, the output end of the second relay valve is connected to the driving cavity of the second air chamber, the first output end of the foot brake valve is connected to the first relay valve, the second output end of the foot brake valve is connected to the second relay valve, the input end of the first air reservoir is connected to the first input end of the foot brake valve, and the input end of the second air reservoir is connected to the second input end of the foot brake valve; The first input end of the differential relay valve is connected to the parking air cylinder, the parking air cylinder is connected to the input end of the hand brake valve, the output end of the hand brake valve is connected to the second input end of the differential relay valve, the third input end of the differential relay valve is connected to the parking cavity of the second air chamber, the fourth input end of the differential relay valve is connected to the output end of the first relay valve, and the fifth input end of the differential relay valve is connected to the output end of the second relay valve.

2. The pneumatic brake system according to claim 1, characterized in that: It also includes four circuits, a first output end of the four circuits is connected to the input end of the first air cylinder, a second output end of the four circuits is connected to the input end of the second air cylinder, a third output end of the four circuits is connected to the parking air cylinder, and an input end of the four circuits is connected to an air compressor.

3. The pneumatic brake system according to claim 2, characterized in that: A dryer is provided between the input end of the four-circuit circuit and the air compressor.

4. The pneumatic brake system according to claim 1, characterized in that: The differential relay valve includes a connecting valve and a variable-section valve core, the first input end and the second input end of the differential relay valve are both connected to the first end of the connecting valve through a one-way valve, the third input end of the differential relay valve is connected to the second end of the connecting valve, an exhaust port is provided on the connecting valve, a movable valve core is movably connected in the connecting valve, the movable valve core is elastically connected to the connecting valve through a spring, the second end of the connecting valve is connected to the exhaust port or the first end of the connecting valve through the movable valve core, a piston rod is movably connected in the variable-section valve core, the piston rod is fixedly connected to the movable valve core, the second input end of the differential relay valve is connected to the first input end of the shuttle valve, the output end of the shuttle valve is connected to the connecting valve, the second input end of the shuttle valve is connected to the rod chamber of the variable-section valve core, the fifth input end of the differential relay valve is connected to the rod chamber of the variable-section valve core, and the fourth input end of the differential relay valve is connected to the rodless chamber of the variable-section valve core.

5. A pneumatic braking method, based on the pneumatic braking system according to claim 4, characterized in that: The following steps are involved: Acquire the status of the hand brake valve and the foot brake valve, and trigger the differential relay valve to work according to the status of the hand brake valve and the foot brake valve to achieve braking; The state of the hand brake valve includes working and disabled, and the state of the foot brake valve includes working and disabled.

6. The pneumatic braking method according to claim 5, characterized in that: The triggering of the differential relay valve to operate according to the states of the hand brake valve and the foot brake valve to achieve the braking operation specifically includes: When the hand brake valve is in working state and the foot brake valve is in disabling state, the first input end of the differential relay valve is ventilated, the second input end, the fourth output end and the fifth output end are cut off, the first relay valve and the second relay valve are not ventilated, the movable valve core connects the second end of the communication valve with the exhaust port, the parking cavity of the second air chamber is deflated, and the parking brake is realized; When the hand brake valve is in the working state, and the foot brake valve is in the working state, the first input end, the fourth output end and the fifth output end of the differential relay valve are ventilated, the second input end is de-energized, the movable valve core connects the second end of the connecting valve with the first end, the parking air cylinder supplies air to the parking cavity of the second air chamber through the differential relay valve, the parking brake is released, the first relay valve and the second relay valve are ventilated, the first air cylinder supplies air to the driving cavity of the first air chamber through the first relay valve, and the second air cylinder supplies air to the driving cavity of the second air chamber through the second relay valve, thereby realizing driving braking.

7. The pneumatic braking method according to claim 5, characterized in that: The method of triggering the operation of the differential relay valve according to the states of the hand brake valve and the foot brake valve to realize the braking operation also includes: When the state of the hand brake valve is disabled and the state of the foot brake valve is disabled, the first input end and the second input end of the differential relay valve are ventilated, the fourth output end and the fifth output end are de-energized, the first relay valve and the second relay valve are not ventilated, the movable valve core connects the first end and the second end of the communication valve, the parking air reservoir supplies air to the parking cavity of the second air chamber through the differential relay valve, the parking brake is released, and the braking operation is not performed; When the hand brake valve is in the disabled state, and the foot brake valve is in the working state, the first input end, the second input end, the fourth output end and the fifth output end of the differential relay valve are ventilated, the first relay valve and the second relay valve are ventilated, the movable valve core connects the second end of the connecting valve with the first end, the parking air cylinder supplies air to the parking cavity of the second air chamber through the differential relay valve, the parking brake is released, the first air cylinder supplies air to the driving cavity of the first air chamber through the first relay valve, and the second air cylinder supplies air to the driving cavity of the second air chamber through the second relay valve, thereby realizing driving braking.

8. The pneumatic braking method according to claim 7, characterized in that: The method of triggering the operation of the differential relay valve according to the states of the hand brake valve and the foot brake valve to realize the braking operation also includes: When the hand brake valve is in the disabled state, the foot brake valve is in the working state, and the first relay valve fails, the first input end, the second input end and the fifth output end of the differential relay valve are ventilated, the fourth output end is de-energized, the second relay valve is ventilated, the movable valve core connects the second end of the connecting valve with the first end, the parking air cylinder supplies air to the parking cavity of the second air chamber through the differential relay valve, the parking brake is released, and the second air cylinder supplies air to the driving cavity of the second air chamber through the second relay valve to realize driving braking.

9. The pneumatic braking method according to claim 7, characterized in that: The method of triggering the operation of the differential relay valve according to the states of the hand brake valve and the foot brake valve to realize the braking operation also includes: When the hand brake valve is in the disabled state, the foot brake valve is in the working state, and the second relay valve fails, the first input end, the second input end and the fourth output end of the differential relay valve are ventilated, the fifth output end is cut off, the first relay valve is ventilated, the movable valve core connects the second end of the connecting valve with the exhaust port, the parking chamber of the second air chamber is deflated, and the first air cylinder supplies air to the driving chamber of the first air chamber through a relay valve to realize driving braking and parking braking.

10. An engineering machine, characterized in that: A pneumatic brake system comprising any one of claims 1 to 4.

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