A multifunctional braking system for engineering machinery

Abstract

The present invention relates to the technical field of engineering machinery braking, and specifically to a multifunctional braking system for engineering machinery, including a parking and auxiliary braking unit, which includes a two-position three-way solenoid valve, a parking brake air chamber, a transmission brake, a pressure switch, and a parking brake switch. The front end of the solenoid valve is connected to the air processing unit, and the rear end is connected to the parking brake air chamber and the transmission brake in sequence. The input end of the pressure switch is connected to the power supply, the output end is connected to the parking brake switch input end, the pressure detection end is connected to the air processing unit, the parking brake switch output end is connected to the solenoid valve coil input end, and the solenoid valve coil output end is grounded. When the solenoid valve is energized, the front and rear air paths are connected; when the solenoid valve is de-energized, the front air path is closed and the rear air path is connected to the atmosphere. The present invention has a simple structure and can achieve parking braking under the active operation of the operator, and can also achieve parking braking without the need for operator operation, thereby improving the braking safety of the braking system.

Description

Technical Field

[0001] The present invention relates to the technical field of engineering machinery braking, in particular to a multifunctional braking system for engineering machinery. Background Art

[0002] In existing construction machinery braking systems, parking and auxiliary braking are often achieved through handbrakes or air brakes. While both braking methods provide normal braking, they can remain energized if the engine stalls or other abnormal conditions occur. If the operator is unconscious or in other extreme situations, unable to operate the handle or brake button, the vehicle can only move in a straight line with uniform deceleration, resulting in long braking distances and a significant safety hazard. Furthermore, most service brake systems utilize a single-line system. If a line leaks or deteriorates, braking may not be possible, also posing a safety hazard. Summary of the Invention

[0003] The purpose of the present invention is to provide a multifunctional braking system for engineering machinery with high safety performance in view of the above problems.

[0004] To achieve the above-mentioned objectives, the present invention discloses a multifunctional braking system for construction machinery, comprising an air handling unit and a parking and auxiliary brake unit, as well as a service brake unit connected to the air handling unit. The parking and auxiliary brake unit comprises a two-position, three-way solenoid valve, a parking brake chamber, a transmission brake, and a normally open pressure switch and a normally closed parking brake switch connected in series. The front end of the solenoid valve is connected to the air handling unit, and the rear end is connected to the air inlet of the parking brake chamber. The output of the parking brake chamber is connected to the transmission brake. The input of the pressure switch is connected to a power supply, the output is connected to the input of the parking brake switch, and the pressure detection end is connected to the air handling unit. The output of the parking brake switch is connected to the input of the solenoid valve coil, and the output of the solenoid valve coil is grounded. When the solenoid valve is energized, the air paths in front and behind it are connected, allowing gas to flow from the front to the rear. When the solenoid valve is de-energized, the air path in front of it is closed, and the air path behind it is connected to the atmosphere.

[0005] Normal parking is achieved by disconnecting the parking brake switch; if the service brake fails, emergency braking can also be achieved by disconnecting the parking brake switch. When the gas pressure entering the pressure switch decreases or disappears, the pressure switch disconnects and emergency braking is automatically achieved. The simple structure can achieve parking braking with the operator's active operation or automatically without the operator's operation, improving the braking safety of the braking system.

[0006] Preferably, the front end of the solenoid valve and the pressure detection end of the pressure switch are connected in parallel and connected to the air handling unit via a first air path. The parking and auxiliary brake unit also includes a one-way control valve that allows gas to flow in the forward direction and can block reverse gas flow by relying on gas pressure, and a first hydraulically controlled one-way valve that only allows gas to flow from front to back and is connected in parallel with the one-way control valve. The one-way control valve and the front end of the first hydraulically controlled one-way valve are connected to the rear end of the solenoid valve, and the rear end is connected to the air inlet of the parking brake chamber. The air path connecting the one-way control valve and the parking brake chamber is also connected to the air handling unit via a second air path, and a switch for controlling its on and off is provided on the second air path. The configuration of the one-way control valve and the switch enables the parking brake to be released after the pressure switch is disconnected, facilitating the transport of the vehicle body.

[0007] Preferably, the parking and auxiliary brake unit also includes a normally open parking relay and an automatic parking relay. The parking relay contact input is connected to the positive power supply, and the output is connected to the solenoid valve coil input. The parking relay coil input is connected to the parking brake switch output, and the output is grounded. The automatic parking relay contact and coil inputs are connected to the power supply and the pressure switch output, respectively, and the automatic parking relay contact and coil outputs are connected in parallel to the parking brake switch input. The provision of the parking relay and automatic parking relay ensures the stability of the braking system circuit.

[0008] Preferably, the air handling unit includes an air compressor, an oil-water separator, an air reservoir, and a safety valve that only transfers air from front to back. The oil-water separator's air inlet is connected to the air compressor's air outlet, which in turn is connected to the safety valve's air inlet. The air reservoir's air inlet is connected to the safety valve's air outlet. The front end of a first air path connects the air path between the safety valve and the oil-water separator, while the front end of a second air path connects to the air reservoir's air outlet. The air compressor dries compressed air through the oil-water separator, and the safety valve ensures stable air transfer to the air reservoir. The first air path is located between the safety valve and the oil-water separator, allowing high-pressure air from the engine's air compressor to enter the first air path directly after drying in the oil-water separator. This ensures the stability of the pressure switch and thus improves the stability of the braking system. The second air path connects to the air reservoir's air outlet. In the event of an abnormal engine shutdown, the higher-pressure air in the air reservoir can be used to release the parking brake. This rational structural arrangement further ensures the stability of the braking system and thus improves its safety.

[0009] Preferably, the air cylinder is a double-chamber air cylinder, including a left air chamber and a right air chamber, and the safety valve includes two second hydraulically controlled one-way valves connected in parallel at the front end, and the air inlets of the two second hydraulically controlled one-way valves are connected to the air outlet of the oil-water separator, wherein the air outlet of one second hydraulically controlled one-way valve is connected to the air inlet of the left air chamber, and the air outlet of the other second hydraulically controlled one-way valve is connected to the air inlet of the right air chamber.

[0010] Preferably, the service brake unit includes a foot brake valve, an air booster pump and a drive axle brake oil chamber, the air processing unit includes an air reservoir, the input end of the foot brake valve is connected to the air outlet of the air reservoir, the output end is connected to the air inlet of the air booster pump, and the output end of the air booster pump is connected to the input end of the drive axle brake oil chamber.

[0011] Preferably, the air reservoir is a dual-chamber air reservoir, including a left air chamber and a right air chamber, which are connected to the air booster pump via a left air circuit and a right air circuit, respectively. The foot brake valve is a two-position control valve with two air inlets and four air outlets. When the foot brake valve pedal is released, the left and right air circuits behind the foot brake valve are both connected to the atmosphere, while the left and right air circuits in front of the foot brake valve are both closed. When the foot brake valve pedal is pressed, the left and right air circuits behind the foot brake valve are connected to the left and right air circuits in front of the foot brake valve, respectively. The provision of dual left and right air circuits allows the vehicle to operate normally in the event of an abnormality such as leakage or aging in one air circuit, while the other air circuit ensures normal braking of the service brake, thereby improving the braking stability of the service brake.

[0012] Preferably, a three-position controlled combined reversing valve is provided on the air circuit behind the foot brake valve and in front of the air booster pump. When the combined reversing valve is in the neutral position, the left and right air circuits behind it are connected to the left and right air circuits in front of it, respectively. When the combined reversing valve is in the left position, only the right air circuit behind it is connected to the right air circuit in front of it. When the combined reversing valve is in the right position, only the left air circuit behind it is connected to the left air circuit in front of it. When the combined reversing valve is in the left or right position, single-circuit control of the service brake can be achieved. When the combined reversing valve is in the neutral position, dual-circuit control of the service brake can be achieved. This provides multiple options for circuit configuration of the service brake unit and improves operational flexibility.

[0013] Preferably, the drive axle brake oil chamber includes a left front drive axle brake oil chamber, a right front drive axle brake oil chamber, a left rear drive axle brake oil chamber, and a right rear drive axle brake oil chamber, the air booster pump includes a front air booster pump and a rear air booster pump, the input ends of the left front drive axle brake oil chamber and the right front drive axle brake oil chamber are connected in parallel and connected to the output end of the front air booster pump, the input ends of the left rear drive axle brake oil chamber and the right rear drive axle brake oil chamber are connected in parallel and connected to the output end of the rear air booster pump, and the left air path and the right air path behind the combined reversing valve are respectively connected to the air inlets of the front air booster pump and the rear air booster pump.

[0014] Preferably, the left and right air paths are each provided with a second one-way valve near the front and rear air booster pump inlets, respectively, that allows air to flow only from the front to the rear. The provision of the second one-way valve prevents air path turbulence, thereby ensuring the stability of service braking.

[0015] In summary, the present invention has the following beneficial effects: It has a simple structure and can achieve both active parking braking with the operator's active operation and automatic parking braking without operator intervention, thus ensuring the brake system's fail-safe function and improving operator safety. The provision of a one-way control valve and switch allows the parking brake to be released after the pressure switch is disconnected, facilitating the transport of vehicles.

[0016] The service brake unit has dual air circuits. If one circuit experiences an abnormality such as leakage or aging, the other circuit can ensure normal service braking, improving service braking stability. The combination reversing valve provides multiple circuit configuration options for the service brake unit, increasing operational flexibility. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a circuit diagram of a multifunctional braking system for engineering machinery according to the present invention (solid lines represent air circuits, and dot-dashed lines represent electrical circuits);

[0018] Figure 2 This is a schematic diagram of the structure of a one-way control valve (the piston is at the far left end, in reverse flow state);

[0019] Figure 3 This is a schematic diagram of the structure of a one-way control valve (the piston is at the far right end and is in the reverse cut-off state);

[0020] In the figure: 11, air reservoir, 111, left air chamber, 112, right air chamber, 12, air compressor, 13, oil-water separator, 14, second hydraulically controlled one-way valve, 15, safety valve, 16, drain valve; 21, foot brake valve, 231, left front drive axle brake oil chamber, 232, right front drive axle brake oil chamber, 233, left rear drive axle brake oil chamber, 234, right rear drive axle brake oil chamber, 24, left air line, 25, right air line, 26, combined reversing valve, 271, front air booster pump, 272, rear air booster pump, 28, second one-way valve; 31, solenoid valve, 32, parking brake chamber, 33, transmission brake, 34, pressure switch, 35, transmission brake, 36, transmission brake, 37, transmission brake, 38, transmission brake, 39, transmission brake, 40, transmission brake, 41, transmission brake, 42, transmission brake, 43, transmission brake, 44, transmission brake, 45, transmission brake, 46, transmission brake, 47, transmission brake, 48, transmission brake, 49, transmission brake, 50, transmission brake, 51, transmission brake, 52, transmission brake, 53, transmission brake, 54, transmission brake, 55, transmission brake, 56, transmission brake, 57, transmission brake, 58, transmission brake, 59, transmission brake, 60, transmission brake, 61, transmission brake, 62, transmission brake, 63, transmission brake, 64, transmission brake, 65, transmission brake, 66, transmission brake, 67, transmission brake, 68, transmission brake, 69, transmission brake, 70, transmission brake, 71, transmission brake, 72, transmission brake, 73, transmission brake, 74, transmission brake, 7 5. Parking relay, 36. Automatic parking relay, 37. Parking brake switch, 38. One-way control valve, 39. Switch, 310. First hydraulically controlled one-way valve, 301. First air path, 302. Second air path, 303. First one-way valve, 3801. Valve body, 3802. Left chamber, 3803. Right chamber, 3804. Middle chamber, 3805. Piston, 3806. Valve core, 3807. Control valve return spring, 3808. Connecting rod, 3809. First channel, 3810. Second channel, 3811. Control channel, 3812. Right limit platform, 3813. Left limit platform, 3814. Inclined surface, 3815. Groove. DETAILED DESCRIPTION

[0021] The following embodiments of the present invention are described in further detail with reference to the accompanying drawings and examples. The following examples are used to illustrate the present invention but are not intended to limit the scope of the present invention.

[0022] In the description of this application, it should be understood that the terms "center", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and the "inner end" and "outer end" are based on the inside and outside of the valve body. The above terms are only for the convenience of describing this application and simplifying the description, and do not indicate or imply 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 on this application.

[0023] The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature specified as "first" or "second" may explicitly or implicitly include one or more of such features. Throughout this application, unless otherwise specified, "plurality" means two or more.

[0024] In the description of this application, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; and internal connections between two components. Those skilled in the art will understand the specific meanings of the above terms in this application based on the specific circumstances.

[0025] The following is a description of preferred embodiments of the present invention with reference to the accompanying drawings.

[0026] like Figure 1 As shown, the present invention discloses a multifunctional braking system for engineering machinery, including an air processing unit, a parking and auxiliary braking unit, and a service braking unit connected to the air processing unit through an air circuit.

[0027] The parking and auxiliary brake unit comprises a two-position, three-way solenoid valve 31, a parking brake chamber 32, a transmission brake 33, and a normally open pressure switch 34 and a normally closed parking brake switch 37 connected in series. The front end of the solenoid valve 31 is connected to the air handling unit via a pneumatic circuit, while the rear end is also connected to the air inlet of the parking brake chamber 32. The output of the parking brake chamber 32 is connected to the transmission brake 33. The input of the pressure switch 34 is connected to a power source, the output is connected to the input of the parking brake switch 37, and the pressure detection end is connected to the air handling unit via a pneumatic circuit. The output of the parking brake switch 37 is connected to the input of the solenoid valve 31 coil, while the output of the solenoid valve 31 coil is grounded. When the solenoid valve 31 is energized, the pneumatic circuits in front and behind it are connected, allowing gas to flow from the front to the rear. When the solenoid valve 31 is de-energized, the pneumatic circuit in front of it is closed, and the pneumatic circuit in the rear is connected to the atmosphere.

[0028] In the parking and auxiliary brake unit, the front end of the solenoid valve 31 is connected in parallel to the pressure detection terminal of the pressure switch 34 and is connected to the air handling unit via a first air path 301. The parking and auxiliary brake unit also includes a one-way control valve 38, which allows gas flow in the forward direction and can block reverse flow based on gas pressure, and a first hydraulically controlled one-way valve 310, which allows gas flow only from front to back and is connected in parallel with the one-way control valve 38. The front ends of the one-way control valve 38 and the first hydraulically controlled one-way valve 310 are connected to the rear end of the solenoid valve 31, and the rear ends are connected to the air inlet of the parking brake chamber 32. The air path connecting the one-way control valve 38 and the parking brake chamber 32 is also connected to the air handling unit via a second air path 302. This second air path 302 is equipped with a switch 39 for controlling its on / off function.

[0029] The parking and auxiliary brake unit also includes a normally open parking relay 35 and an automatic parking relay 36. The input of the parking relay 35 contact is connected to the positive terminal of the power supply, and the output is connected to the input of the coil of the solenoid valve 31. The input of the parking relay 35 coil is connected to the output of the parking brake switch 37, and the output is grounded. The input of the automatic parking relay 36 contact and coil are connected to the power supply and the output of the pressure switch 34, respectively. The output of the automatic parking relay 36 contact and coil is connected in parallel to the input of the parking brake switch 37.

[0030] The air handling unit includes an air compressor 12, an oil-water separator 13, an air reservoir 11, and a safety valve that only transfers air from front to back. The air inlet of the oil-water separator 13 is connected to the air outlet of the air compressor 12, which in turn is connected to the air inlet of the safety valve. The air inlet of the air reservoir 11 is connected to the air outlet of the safety valve. The front end of a first air path 301 connects the air path between the safety valve and the oil-water separator 13, while the front end of a second air path 302 connects to the air outlet of the air reservoir 11.

[0031] The air storage cylinder 11 in the air handling unit is a dual-chamber air storage cylinder, including a left air chamber 111 and a right air chamber 112. The safety valve includes two second hydraulically controlled one-way valves 14 connected in parallel at the front end. The second hydraulically controlled one-way valves 14 can only transfer gas from front to back. The air inlets of the two second hydraulically controlled one-way valves 14 are connected to the air outlet of the oil-water separator 13. The air outlet of one second hydraulically controlled one-way valve 14 is connected to the air inlet of the left air chamber 111, and the air outlet of the other second hydraulically controlled one-way valve 14 is connected to the air inlet of the right air chamber 112. The left air chamber 111 and the right air chamber 112 are respectively connected to two safety valves 15, which can ensure that the pressure of the left air chamber 111 and the right air chamber 112 does not exceed the rated value; the left air chamber 111 and the right air chamber 112 are also respectively connected to two drain valves 16 to ensure that the interior of the left air chamber 111 and the right air chamber 112 are dry. The front end of the second air path 302 is connected to the air outlets of the left air chamber 111 and the right air chamber 112 respectively.

[0032] The service brake unit includes a foot brake valve 21, an air booster pump, and a drive axle brake oil chamber. The foot brake valve 21's input is connected to the air outlet of the air reservoir 11, and its output is connected to the air inlet of the air booster pump. The air booster pump's output is connected to the drive axle brake oil chamber's input. The left and right air chambers 111 and 112 are connected to the air booster pump via left and right air paths 24 and 25, respectively. The foot brake valve 21 is a two-position control valve with two inlets and four outlets. When the pedal of the foot brake valve 21 is released, the foot brake valve 21 is in the left position, and the left air path 24 and the right air path 25 behind the foot brake valve 21 are connected to the atmosphere through the air outlet of the foot brake valve 21 respectively, and the left air path 24 and the right air path 25 in front are both closed; when the pedal of the foot brake valve 21 is pressed, the foot brake valve 21 is in the right position, and the left air path 24 and the right air path 25 behind the foot brake valve 21 are connected to the left air path 24 and the right air path 25 in front of it through two air inlets and air outlets respectively, so that the gas in the air path in front of the foot brake valve 21 is transferred from front to back to the air path behind it.

[0033] A three-position controlled combined reversing valve 26 is provided on the air path behind the foot brake valve 21 and in front of the air booster pump. When the combined reversing valve 26 is in the middle position, the left air path 24 and the right air path 25 behind it are connected to the left air path 24 and the right air path 25 in front of it, respectively, so that the gas in the left air path 24 and the right air path 25 in front of the combined reversing valve 26 is transferred from front to back to the left air path 24 and the right air path 25 behind it, respectively; when the combined reversing valve 26 is in the left position, only the right air path 25 behind it is connected to the right air path 25 in front of it, so that only the gas in the right air path 25 in front of the combined reversing valve 26 is transferred from front to back to the right air path 25 behind it; when the combined reversing valve 26 is in the right position, only the left air path 24 behind it is connected to the left air path 24 in front of it, so that only the gas in the left air path 24 in front of the combined reversing valve 26 is transferred from front to back to the left air path 24 behind it.

[0034] The drive axle brake oil chambers include a left front drive axle brake oil chamber 231, a right front drive axle brake oil chamber 232, a left rear drive axle brake oil chamber 233, and a right rear drive axle brake oil chamber 234. The air booster pumps include a front air booster pump 271 and a rear air booster pump 272. The input ends of the left front drive axle brake oil chamber 231 and the right front drive axle brake oil chamber 232 are connected in parallel and to the output end of the front air booster pump 271. The input ends of the left rear drive axle brake oil chamber 233 and the right rear drive axle brake oil chamber 234 are connected in parallel and to the output end of the rear air booster pump 272. The left air path 24 and the right air path 25 behind the combination reversing valve 26 are both connected to the air inlets of the front air booster pump 271 and the rear air booster pump 272, respectively. The left air path 24 and the right air path 25 are both provided with a second one-way valve 28 at the intersection close to the air inlet of the front air booster pump 271 and the air inlet of the rear air booster pump 272 respectively, which can only allow gas to pass from front to rear.

[0035] In order to further prevent the gas in the gas storage cylinder 11 from flowing back to the first gas path 301, a first one-way valve 303 that can only allow gas to pass from front to back is provided on the gas path between the safety valve and the oil-water separator 13, and the front end of the first gas path 301 is connected to the gas path between the oil-water separator and the first one-way valve 303.

[0036] like Figure 2 and Figure 3 As shown, in the parking and auxiliary brake unit, the one-way control valve 38 includes a valve body 3801, which defines a left chamber 3802, a right chamber 3803, and a middle chamber 3804 that connects the left chamber 3802 and the right chamber 3803. The left chamber 3802, the right chamber 3803, and the middle chamber 3804 are all circular in cross-section and are coaxially arranged.

[0037] A valve core 3806 is mounted within the right chamber 3803, allowing it to move left and right within the chamber. The right side of the valve core 3806 is connected to the right side wall of the right chamber 3803 via a control valve return spring 3807. A coaxial groove 3815 is defined on the right side of the valve core 3806, and the left end of the control valve return spring 3807 is fixedly connected to the left side of the groove 3815. A piston 3805 is mounted within the left chamber 3802, allowing it to move left and right within the chamber. The piston 3805 and valve core 3806 are connected by a connecting rod 3808. The cross-sectional profiles of both the piston 3805 and valve core 3806 are circular, corresponding to the left and right chambers 3802 and 3803, respectively. The radius of the middle chamber 3804 is smaller than that of the left chamber 3802 and the right chamber 3803, so that the right end surface of the left chamber 3802 forms the right limit platform 3812 of the piston 3805, and the left end surface of the right chamber 3803 forms the left limit platform 3813 of the valve core 3806.

[0038] A first channel 3809 is defined on the circumferential sidewall of the middle chamber 3804, communicating with the outside. A second channel 3810 is defined on the right circumferential sidewall of the left chamber 3802, communicating with the outside. A control channel 3811 is defined on the left sidewall of the left chamber 3802, communicating with the outside. The outer end of the control channel 3811 is connected to the second channel 3810, i.e., the control channel 3811 communicates with the outside through the second channel 3810. The outer end of the first channel 3809 is connected to the rear end of the solenoid valve 31, while the outer end of the second channel 3810 is connected to the second air path 302 and the parking brake air chamber 32, respectively, via a three-way connector.

[0039] like Figure 3 As shown, when the piston 3805 moves rightward to the rightmost end, the valve core 3806 is located at the rightmost end. At this time, the second channel 3810 and the middle chamber 3804 are closed by the piston 3805. Figure 2 As shown, when the piston 3805 moves to the leftmost end, the valve core 3806 is at the leftmost end. At this time, the second channel 3810 is connected to the middle chamber 3804 through the left chamber 3802; the first channel 3809 is always connected to the middle chamber 3804. The right end face of the piston 3805 and the outer side face are connected at a right angle or bevel to form an inclined surface 3814. When the piston 3805 moves to the rightmost end, the inclined surface 3814 abuts the right limit plate 3812. Figure 3 As shown, in order to ensure that the piston 3805 can completely abut against the right limit platform 3812, when the valve core 3806 moves to the rightmost end, a gap is left between the right end surface of the valve core 3806 and the right side surface of the right chamber 3803.

[0040] In this embodiment, the flow of fluid, such as gas or hydraulic oil, from second channel 3810 to first channel 3809 is assumed to be in the reverse direction, from back to front, while the flow from first channel 3809 to second channel 3810 is assumed to be in the forward direction, from front to back. The initial state of one-way control valve 38 is such that piston 3805 and valve core 3806 are both positioned at the far left end.

[0041] When the fluid is flowing in the reverse direction, the fluid enters the second channel 3810 from the outer end of the second channel 3810. A portion of the fluid passes through the right portion of the left chamber 3802, the middle chamber 3804, and the first channel 3809 in sequence, reaching the pipeline or other components connected to the outer end of the first channel 3809 and located in front of the one-way control valve 38. The remaining portion of the fluid enters the left portion of the left chamber 3802 from the control channel 3811, pressing the piston 3805 to move rightward and compressing the control valve return spring 3807 on the right side of the valve core 3806. When the fluid entering the left portion of the left chamber 3802 from the control channel 3811 pushes the piston 3805 to the rightmost end, the one-way control valve 38 stops the forward flow of the fluid. That is, when the fluid is flowing in the reverse direction, a small amount of fluid or fluid with low pressure can pass through the one-way control valve 38 and enter the pipeline or other components connected to it. When the fluid pressure increases to the point where the piston 3805 moves rightward to the rightmost end, the one-way control valve 38 stops the forward flow of the fluid.

[0042] The design and adjustment of the size of the one-way control valve 38 as a whole and each component can be made according to actual needs, so that when the fluid is transmitted in the opposite direction, the fluid pressure of the fluid that needs to be cut off can move the piston 3805 to the rightmost end and thus disconnect the one-way control valve 38, so that the fluid that does not need to be cut off can directly pass through the one-way control valve 38 in the opposite direction. The size of the one-way control valve 38 as a whole and each component is not specifically limited here.

[0043] In a multifunctional braking system for engineering machinery disclosed in the present invention, the engine's air compressor 12 dries the compressed air through an oil-water separator 13 and then enters the left air chamber 111 and the right air chamber 112 of the air reservoir 11 through a safety valve composed of two second hydraulically controlled one-way valves 14.

[0044] like Figure 1 As shown, when braking is required during driving, the foot brake valve 21 is depressed to the right position. The gas in the air reservoir 11 passes through the foot brake valve 21 and the combined reversing valve 26 and enters the right chambers of the front air booster pump 271 and the rear air booster pump 272. This pushes the brake fluid in the left chambers of the front air booster pump 271 and the rear air booster pump 272 into the cylinders of the left front drive axle brake oil chamber 231, the right front drive axle brake oil chamber 232, the left rear drive axle brake oil chamber 233, and the right rear drive axle brake oil chamber 234, respectively, to achieve service braking. When the foot brake valve 21 is released, the foot brake valve 21 returns to its original position, and the service brake is released.

[0045] like Figure 1As shown, during driving, under the action of the safety valve, the high-pressure gas of the engine's air compressor 12 is dried by the oil-water separator 13 and directly enters the first gas path 301. One gas on the first gas path 301 enters the pressure detection end of the pressure switch 34, closing the pressure switch 34. At this time, the contacts of the automatic parking relay 36 are attracted. Since the parking brake switch 35 is a normally closed switch, the contacts of the parking relay 35 are attracted, energizing the coil of the solenoid valve 31 to make it located in the left position. The other gas on the first gas path 301 passes through the solenoid valve 31 and then passes through the first hydraulically controlled one-way valve 310 to enter the parking brake air chamber 32 to compress the right return spring, so that the transmission brake 33 is in the disengaged state.

[0046] When the vehicle stops, the parking brake switch 37 is disconnected, de-energizing the parking relay 35 coil and opening its contacts. This in turn de-energizes the solenoid valve 31 coil, and the right return spring forces the solenoid valve 31 to the right position. Because the amount of gas and pressure in the left chamber of the parking brake chamber 32 are low, the gas in the left chamber of the parking brake chamber 32 can be directly discharged into the atmosphere through the one-way control valve 38 and the solenoid valve 31. The right return spring of the parking brake chamber 32 activates the transmission brake 33, achieving normal parking braking. If the service brake fails, abnormal braking can also be achieved by closing the parking brake switch 35.

[0047] During an abnormal engine shutdown, the engine's air compressor 12 can no longer supply air to first air path 301. However, power is still present in the system. The pressure drop causes pressure switch 34 to trip, disconnecting the contacts of automatic parking relay 36 and parking relay 35. This in turn de-energizes the coil of solenoid valve 31, placing it in the right position. The air in the left chamber of parking brake chamber 32 is discharged directly through one-way control valve 38 and solenoid valve 31 into the atmosphere. The return spring on the right side of parking brake chamber 32 activates transmission brake 33, achieving abnormal parking braking.

[0048] When a vehicle needs to be checked due to an abnormal engine shutdown, switch 39 is closed. Due to the high gas pressure still present in air reservoir 11 and the safety valve located in front of air reservoir 11, the high-pressure gas in air reservoir 11 can only enter second air path 302. After passing through the tee, one path of gas from second air path 302 enters the left portion of left chamber 3802 of one-way control valve 38 from the outer end of second channel 3810. This pushes piston 3805 rightward to its rightmost end and compresses control valve return spring 3807. At this point, inclined surface 3814 abuts right stop 3812, preventing gas in second channel 3810 from passing through left chamber 3802 and into middle chamber 3804. One-way control valve 38 then blocks gas from second air path 302 to solenoid valve 31. Another path of gas enters parking brake chamber 32, compressing the right return spring, disengaging transmission brake 33 and releasing the parking brake.

[0049] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and substitutions can be made without departing from the technical principles of the present invention. These improvements and substitutions should also be regarded as the scope of protection of the present invention.

Claims

1. A multifunctional braking system for engineering machinery, characterized in that: It includes an air handling unit and a parking and auxiliary brake unit, and also includes a service brake unit connected to the air handling unit; The parking and auxiliary brake unit includes a two-position three-way solenoid valve (31), a parking brake air chamber (32), a transmission brake (33), and also includes a normally open pressure switch (34) and a normally closed parking brake switch (37) connected in series. The front end of the solenoid valve (31) is connected to the air processing unit, and the rear end is connected to the air inlet of the parking brake air chamber (32). The output end of the parking brake air chamber (32) is connected to the transmission brake (33). The input end of the pressure switch (34) is connected to the power supply, the output end is connected to the input end of the parking brake switch (37), and the pressure detection end is connected to the air processing unit. The output end of the parking brake switch (37) is connected to the input end of the solenoid valve (31) coil, and the output end of the solenoid valve (31) coil is grounded. When the solenoid valve (31) is energized, the air paths in front and behind it are connected. When the solenoid valve (31) is de-energized, the air path in front of it is closed, and the air path behind it is connected to the atmosphere. The front end of the solenoid valve (31) and the pressure detection end of the pressure switch (34) are connected in parallel and connected to the air processing unit through a first air path (301). The parking and auxiliary brake unit also includes a one-way control valve (38) that can transmit gas in the forward direction and can cut off the reverse flow of gas by relying on gas pressure, and a first hydraulically controlled one-way valve (310) that can only transmit gas from front to back and is connected in parallel with the one-way control valve (38). The front ends of the one-way control valve (38) and the first hydraulically controlled one-way valve (310) are connected to the rear end of the solenoid valve (31), and the rear end is connected to the air inlet of the parking brake air chamber (32). The air path connecting the one-way control valve (38) and the parking brake air chamber (32) is also connected to the air processing unit through a second air path (302). The second air path (302) is provided with a switch (39) for controlling its on and off. The one-way control valve (38) comprises a valve body (3801), wherein a left chamber (3802), a right chamber (3803) and an intermediate chamber (3804) communicating with the left chamber (3802) and the right chamber (3803) are provided in the valve body (3801), wherein the left chamber (3802), the right chamber (3803) and the intermediate chamber (3804) are all circular in cross-section and are coaxially arranged. The parking and auxiliary brake unit further includes a normally open parking relay (35) and an automatic parking relay (36), wherein the input end of the parking relay (35) contact is connected to the positive electrode of the power supply, and the output end is connected to the input end of the solenoid valve (31); the input end of the parking relay (35) coil is connected to the output end of the parking brake switch (37), and the output end is grounded; the input end of the automatic parking relay (36) contact and coil are respectively connected to the power supply and the output end of the pressure switch (34); the output end of the automatic parking relay (36) contact and coil is connected in parallel to the input end of the parking brake switch (37).

2. The multifunctional braking system for engineering machinery according to claim 1, characterized in that: The air processing unit comprises: an air compressor (12), an oil-water separator (13), an air storage cylinder (11), and a safety valve capable of transmitting gas only from front to back; the air inlet of the oil-water separator (13) is connected to the air outlet of the air compressor (12), and the air outlet is connected to the air inlet of the safety valve; the air inlet of the air storage cylinder (11) is connected to the air outlet of the safety valve; the front end of the first air path (301) is connected to the air path between the safety valve and the oil-water separator (13); and the front end of the second air path (302) is connected to the air outlet of the air storage cylinder (11).

3. The multifunctional braking system for engineering machinery according to claim 2, characterized in that: The air storage cylinder (11) is a double-chamber air storage cylinder, comprising a left air chamber (111) and a right air chamber (112); the safety valve comprises two second hydraulically controlled one-way valves (14) connected in parallel at the front end; the air inlets of the two second hydraulically controlled one-way valves (14) are connected to the air outlet of the oil-water separator (13); the air outlet of one second hydraulically controlled one-way valve (14) is connected to the air inlet of the left air chamber (111), and the air outlet of the other second hydraulically controlled one-way valve (14) is connected to the air inlet of the right air chamber (112).

4. The multifunctional braking system for engineering machinery according to claim 1, characterized in that: The service brake unit comprises a foot brake valve (21), an air booster pump and a drive axle brake oil chamber, the air processing unit comprises an air reservoir (11), the input end of the foot brake valve (21) is connected to the air outlet of the air reservoir (11), the output end is connected to the air inlet of the air booster pump, and the output end of the air booster pump is connected to the input end of the drive axle brake oil chamber.

5. The multifunctional braking system for engineering machinery according to claim 4, characterized in that: The air reservoir (11) is a double-chamber air reservoir, comprising a left air chamber (111) and a right air chamber (112). The left air chamber (111) and the right air chamber (112) are connected to the air booster pump via a left air path (24) and a right air path (25), respectively. The foot brake valve (21) is a two-position control valve comprising two air inlets and four air outlets. When the pedal of the foot brake valve (21) is released, the left air path (24) and the right air path (25) behind the foot brake valve (21) are both connected to the atmosphere, and the left air path (24) and the right air path (25) in front of the foot brake valve (21) are both closed. When the pedal of the foot brake valve (21) is depressed, the left air path (24) and the right air path (25) behind the foot brake valve (21) are respectively connected to the left air path (24) and the right air path (25) in front of the foot brake valve (21).

6. The multifunctional braking system for engineering machinery according to claim 5, characterized in that: A three-position controlled combined reversing valve (26) is provided on the air path behind the foot brake valve (21) and in front of the air booster pump. When the combined reversing valve (26) is in the middle position, the left air path (24) and the right air path (25) behind it are respectively connected to the left air path (24) and the right air path (25) in front of it. When the combined reversing valve (26) is in the left position, only the right air path (25) behind it is connected to the right air path (25) in front of it. When the combined reversing valve (26) is in the right position, only the left air path (24) behind it is connected to the left air path (24) in front of it.

7. The multifunctional braking system for engineering machinery according to claim 6, characterized in that: The drive axle brake oil chamber comprises a left front drive axle brake oil chamber (231), a right front drive axle brake oil chamber (232), a left rear drive axle brake oil chamber (233), and a right rear drive axle brake oil chamber (234); the air booster pump comprises a front air booster pump (271) and a rear air booster pump (272); the input ends of the left front drive axle brake oil chamber (231) and the right front drive axle brake oil chamber (232) are connected in parallel and connected to the output end of the front air booster pump (271); the input ends of the left rear drive axle brake oil chamber (233) and the right rear drive axle brake oil chamber (234) are connected in parallel and connected to the output end of the rear air booster pump (272); and the left air path (24) and the right air path (25) behind the combined reversing valve (26) are both connected to the air inlets of the front air booster pump (271) and the rear air booster pump (272), respectively.

8. The multifunctional braking system for engineering machinery according to claim 7, characterized in that: The left air path (24) and the right air path (25) are both provided with a second one-way valve (28) near the air inlet of the front air booster pump (271) and the air inlet of the rear air booster pump (272), respectively, which can only allow gas to pass from the front to the rear.

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