CN220884353U - Multifunctional braking system of engineering machinery - Google Patents

Abstract

The utility model relates to the technical field of engineering machinery braking, in particular to a multifunctional braking system of engineering machinery, which comprises a parking and auxiliary braking unit, wherein the parking and auxiliary braking unit comprises a two-position three-way electromagnetic valve, a parking braking air chamber, a gearbox brake, a pressure switch and a parking braking switch. The front end of the electromagnetic valve is connected with the air processing unit, the rear end of the electromagnetic valve is sequentially connected with the parking brake air chamber and the gearbox brake, the input end of the pressure switch is connected with the power supply, the output end of the pressure switch is connected with the input end of the parking brake switch, the pressure detection end of the pressure switch is connected with the air processing unit, the output end of the parking brake switch is connected with the input end of the electromagnetic valve coil, and the output end of the electromagnetic valve coil is grounded. The electromagnetic valve is electrified, and the air paths at the front and the rear of the electromagnetic valve are communicated; the electromagnetic valve is powered off, the front air passage is closed, and the rear air passage is communicated with the atmosphere. The utility model has simple structure, can realize the parking brake under the active operation of operators, can realize the parking brake under the condition of no operation of operators, and improves the braking safety of a braking system.

Description

Multifunctional braking system of engineering machinery

Technical Field

The utility model relates to the technical field of engineering machinery braking, in particular to a multifunctional braking system of engineering machinery.

Background

In the existing engineering machinery braking system, the parking and auxiliary braking are mostly in a hand braking flexible shaft or air breaking braking mode, normal braking can be achieved in two braking modes, but when an engine is abnormally flameout or other abnormal conditions occur, a circuit in the system is still in an electrified state, if an operator is in an unconscious or other extreme conditions at this time, a handle or a braking button cannot be normally operated, at this time, the vehicle can only perform uniform deceleration linear motion, the braking distance is large, and great potential safety hazards exist. In addition, the service brake system is mostly in a single-pipeline form, and if abnormal conditions such as pipeline leakage, aging and the like occur, normal braking cannot be realized, and potential safety hazards exist.

Disclosure of Invention

The utility model aims to provide a multifunctional braking system of engineering machinery with high safety performance.

In order to achieve the aim, the utility model discloses a multifunctional braking system of engineering machinery, which comprises an air processing unit, a parking and auxiliary braking unit and a service braking unit connected with the air processing unit. The parking and auxiliary braking unit comprises a two-position three-way electromagnetic valve, a parking braking air chamber, a gearbox brake, a normally open type pressure switch and a normally closed type parking braking switch which are connected in series. The front end of the electromagnetic valve is connected with the air processing unit, the rear end of the electromagnetic valve is connected with the air inlet of the parking brake air chamber, the output end of the parking brake air chamber is connected with the gearbox brake, the input end of the pressure switch is connected with the power supply, the output end of the pressure switch is connected with the input end of the parking brake switch, the pressure detection end is connected with the air processing unit, the output end of the parking brake switch is connected with the input end of the electromagnetic valve coil, and the output end of the electromagnetic valve coil is grounded. When the electromagnetic valve is powered on, the air channels in front of and behind the electromagnetic valve are communicated, air can be transferred from the front to the rear of the electromagnetic valve, when the electromagnetic valve is powered off, the air channel in front of the electromagnetic valve is closed, and the air channel behind the electromagnetic valve is communicated with the atmosphere.

The normal parking brake can be realized by switching off the parking brake switch; when the service brake fails, abnormal braking can be realized by switching off the parking brake switch; when the pressure of the gas entering the pressure switch is reduced or eliminated, the pressure switch is disconnected to automatically realize abnormal braking. The automatic parking brake device has the advantages that the structure is simple, the parking brake can be realized under the active operation of operators, the automatic parking brake can be realized under the condition that the operation of operators is not needed, and the braking safety of a braking system is improved.

Preferably, the front end of the electromagnetic valve is connected in parallel with the pressure detection end of the pressure switch and is connected with the air processing unit through a first air passage, the parking and auxiliary braking unit further comprises a one-way control valve which can enable air to be transmitted forward and stop air from flowing reversely by means of air pressure, and a first hydraulic control one-way valve which can enable air to be transmitted forward and backward only and is connected with the one-way control valve in parallel. The front ends of the one-way control valve and the first hydraulic control one-way valve are connected with the rear end of the electromagnetic valve, the rear end of the one-way control valve is connected with the air inlet of the parking brake air chamber, the air path connected with the one-way control valve and the parking brake air chamber is also connected with the air treatment unit through a second air path, and a switch for controlling the on-off of the air treatment unit is arranged on the second air path. The one-way control valve and the switch can be arranged to release the parking brake after the parking brake is realized due to the disconnection of the pressure switch, so that the vehicle body can be conveniently transported.

Preferably, the parking and auxiliary braking unit further comprises a normally open parking relay and an automatic parking relay, wherein the input end of a parking relay contact is connected with the positive electrode of the power supply, the output end of the parking relay contact is connected with the input end of the solenoid valve coil, the input end of the parking relay coil is connected with the output end of the parking brake switch, the output end of the parking relay coil is grounded, the input ends of the automatic parking relay contact and the coil are respectively connected with the output end of the power supply and the pressure switch, and the output ends of the automatic parking relay contact and the coil are connected with the input end of the parking brake switch in parallel. The arrangement of the parking relay and the automatic parking relay ensures the stability of a braking system circuit.

Preferably, the air treatment unit comprises: the air compressor, the oil-water separator, the gas receiver and the safety valve capable of only transmitting gas from front to back are arranged, the air inlet of the oil-water separator is connected with the air outlet of the air compressor, the air outlet of the oil-water separator is connected with the air inlet of the safety valve, the air inlet of the gas receiver is connected with the air outlet of the safety valve, the front end of the first air channel is communicated with the air channel between the safety valve and the oil-water separator, and the front end of the second air channel is connected with the air outlet of the gas receiver. The air compressor dries the compressed air through the oil-water separator, and then the safety valve enables the gas to be stably transferred into the gas storage cylinder. The first air path is arranged between the safety valve and the oil-water separator, so that high-pressure gas of the air compressor of the engine directly enters the first air path after being dried by the oil-water separator, the stability of the pressure switch pressure can be ensured, and the stability of a braking system is further improved. The second air circuit is connected with the air outlet of the air cylinder, and after the engine is abnormally flameout, the parking brake can be released by utilizing the gas with higher pressure in the air cylinder. The structure is reasonable, the stability of the braking system is further guaranteed, and the safety of the braking system is further improved.

Preferably, the air storage cylinder is a double-air-chamber air storage cylinder and comprises a left air chamber and a right air chamber, the safety valve comprises two second hydraulic control check valves, the front ends of the two second hydraulic control check valves are connected in parallel, air inlets of the two second hydraulic control check valves are connected with air outlets of the oil-water separator, the air outlet of one second hydraulic control check valve is connected with the air inlet of the left air chamber, and the air outlet of the other second hydraulic control check valve is connected with the air inlet of the right air chamber.

Preferably, the service brake unit comprises a foot brake valve, an air booster pump and a drive axle brake oil chamber, the air treatment unit comprises an air storage cylinder, the input end of the foot brake valve is connected with the air outlet of the air storage cylinder, the output end of the foot brake valve is connected with the air inlet of the air booster pump, and the output end of the air booster pump is connected with the input end of the drive axle brake oil chamber.

Preferably, the air storage cylinder is a double-air-chamber air storage cylinder and comprises a left air chamber and a right air chamber, the left air chamber and the right air chamber are respectively connected with an air booster pump through a left air passage and a right air passage, the foot brake valve is a two-position control valve comprising two air inlets and four air outlets, when the foot brake valve pedal is released, the left air passage and the right air passage behind the foot brake valve are communicated with atmosphere, the left air passage and the right air passage in front are sealed, and when the foot brake valve pedal is stepped on, the left air passage and the right air passage behind the foot brake valve are respectively communicated with the left air passage and the right air passage in front. The left gas path and the right gas path are arranged, when abnormal conditions such as leakage or aging of one gas path occur, the other gas path can ensure normal braking of service braking, and the braking stability of the service braking can be improved.

Preferably, a three-position controlled combined reversing valve is arranged on the air passage behind the foot brake valve and in front of the air booster pump, when the combined reversing valve is positioned in the middle position, the left air passage and the right air passage behind the combined reversing valve are respectively communicated with the left air passage and the right air passage in front of the combined reversing valve, when the combined reversing valve is positioned in the left position, only the right air passage behind the combined reversing valve is communicated with the right air passage in front of the combined reversing valve, and when the combined reversing valve is positioned in the right position, only the left air passage behind the combined reversing valve is communicated with the left air passage in front of the combined reversing valve. When the combined reversing valve is in the left position and the right position, single-pipeline control of service braking can be realized, and when the combined reversing valve is in the middle position, double-pipeline control of service braking can be realized, so that multiple choices are arranged in a loop of a service braking unit, and the operation flexibility is improved.

Preferably, the driving axle braking oil chamber comprises a left front driving axle braking oil chamber, a right front driving axle braking oil chamber, a left rear driving axle braking oil chamber and a right rear driving axle braking oil chamber, the air booster pump comprises a front air booster pump and a rear air booster pump, the input ends of the left front driving axle braking oil chamber and the right front driving axle braking oil chamber are connected in parallel and are connected with the output ends of the front air booster pump, the input ends of the left rear driving axle braking oil chamber and the right rear driving axle braking oil chamber are connected in parallel and are connected with the output ends of the rear air booster pump, and a left air channel and a right air channel behind the combined reversing valve are respectively communicated with the air inlets of the front air booster pump and the rear air booster pump.

Preferably, the left air passage and the right air passage are respectively provided with a second one-way valve which can only transmit the air from front to back at the positions close to the air inlets of the front air booster pump and the rear air booster pump. The arrangement of the second one-way valve can avoid the disorder of the air path, and further ensure the stability of service braking.

In summary, the beneficial effects of the utility model are as follows: the utility model has simple structure, can realize the parking brake under the active operation of operators, and can realize the automatic parking brake under the condition of no operation of operators, thereby ensuring the failure safety of a brake system and improving the operation safety of operators. The one-way control valve and the switch can be arranged to release the parking brake after the parking brake is realized due to the disconnection of the pressure switch, so that the vehicle body can be conveniently transported.

The double air paths are arranged in the driving braking unit, and when one air path leaks or ageing and other abnormal conditions occur, the other air path can ensure normal braking of the driving braking, and the braking stability of the driving braking can be improved. The arrangement of the combined reversing valve enables the loop of the service brake unit to be provided with various choices, and the operation flexibility is improved.

Drawings

FIG. 1 is a circuit diagram of a multifunctional brake system for construction machinery (solid lines are air paths, and dash-dot lines are circuits) according to the present utility model;

FIG. 2 is a schematic illustration of the configuration of the one-way control valve (with the piston at the far left end, in reverse flow);

FIG. 3 is a schematic view of the structure of the one-way control valve (piston at the far right end, in reverse cut-off state);

In the figure: 11. the air storage cylinder, 111, a left air chamber, 112, a right air chamber, 12, an air compressor, 13, an oil-water separator, 14, a second hydraulic control one-way valve, 15, a safety valve, 16 and a water 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 passage, 25, right air passage, 26, combined reversing valve, 271, front air booster pump, 272, rear air booster pump, 28, second check valve; 31. solenoid valve, 32, parking brake chamber, 33, gearbox brake, 34, pressure switch, 35, parking relay, 36, automatic parking relay, 37, parking brake switch, 38, one-way control valve, 39, switch, 310, first pilot operated 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 stop, 3813, left stop, 3814, inclined surface, 3815, groove.

Detailed Description

The following describes in further detail the embodiments of the present utility model with reference to the drawings and examples. The following examples are illustrative of the utility model and are not intended to limit the scope of the utility model.

In the description of the present application, it should be understood that the terms "center," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," and the like indicate orientations or positional relationships based on the orientation or positional relationships shown in the drawings, and that the "inner end" and "outer end" are merely used for convenience in describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a specific orientation, be configured and operated in a specific orientation, and thus should not be construed as limiting the present application.

The terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include one or more such feature. In the description of the present application, unless otherwise indicated, the meaning of "a plurality" is two or more.

In the description of the present application, it should be noted that, unless explicitly specified and limited otherwise, the terms "mounted," "connected," and "connected" are to be construed broadly, and may be either fixedly connected, detachably connected, or integrally connected, for example; can be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium, and can be communication between two elements. The specific meaning of the above terms in the present application will be understood in specific cases by those of ordinary skill in the art.

The following is a description of a preferred embodiment of the utility model, taken in conjunction with the accompanying drawings.

As shown in fig. 1, the utility model discloses a multifunctional braking system of engineering machinery, which comprises an air processing unit, a parking and auxiliary braking unit and a service braking unit connected with the air processing unit through an air path.

The parking and auxiliary braking unit comprises a two-position three-way electromagnetic valve 31, a parking braking air chamber 32, a gearbox brake 33, a normally open type pressure switch 34 and a normally closed type parking braking switch 37 which are connected in series. The front end of the electromagnetic valve 31 is connected with an air processing unit through an air passage, the rear end of the electromagnetic valve 31 is connected with an air inlet of the parking brake air chamber 32 through an air passage, the output end of the parking brake air chamber 32 is connected with the gearbox brake 33, the input end of the pressure switch 34 is connected with a power supply, the output end of the pressure switch is connected with the input end of the parking brake switch 37, the pressure detection end of the pressure switch is connected with the air processing unit through the air passage, the output end of the parking brake switch 37 is connected with the input end of the coil of the electromagnetic valve 31, and the output end of the coil of the electromagnetic valve 31 is grounded. When the solenoid valve 31 is energized, the gas paths in front and behind thereof are turned on, gas can be transferred from the front to the rear thereof, and when the solenoid valve 31 is deenergized, the gas path in front thereof is closed, and the gas path behind thereof is communicated with the atmosphere.

In the parking and auxiliary brake unit, the front end of the solenoid valve 31 and the pressure detecting end of the pressure switch 34 are connected in parallel and connected to the air handling unit through the first air passage 301. The parking and auxiliary brake unit further includes a one-way control valve 38 capable of forward transfer of gas and blocking reverse circulation of gas by means of gas pressure, and a first pilot operated one-way valve 310 capable of forward-backward transfer of gas only and connected in parallel with the one-way control valve 38. The front end of the one-way control valve 38 and the front end of the first hydraulic control one-way valve 310 are connected with the rear end of the electromagnetic valve 31, the rear end of the one-way control valve is connected with the air inlet of the parking brake air chamber 32, the air path of the one-way control valve 38 connected with the parking brake air chamber 32 is also connected with an air treatment unit through a second air path 302, and a switch 39 for controlling the on-off of the second air path 302 is arranged on the second air path.

The parking and auxiliary brake unit further comprises a normally open parking relay 35 and an automatic parking relay 36. The input end of the parking relay 35 contact is connected with the positive electrode of the power supply, the output end of the parking relay 35 contact is connected with the input end of the coil of the electromagnetic valve 31, the input end of the parking relay 35 coil is connected with the output end of the parking brake switch 37, the output end of the parking brake switch is grounded, the input ends of the automatic parking relay 36 contact and the coil are respectively connected with the output ends of the power supply and the pressure switch 34, and the output ends of the automatic parking relay 36 contact and the coil are connected in parallel to the input end of the parking brake switch 37.

The air treatment unit includes: an air compressor 12, an oil-water separator 13, an air reservoir 11, and a relief valve for delivering air only from front to back. The air inlet of the oil-water separator 13 is connected with the air outlet of the air compressor 12, the air outlet is connected with the air inlet of the safety valve, the air inlet of the air storage cylinder 11 is connected with the air outlet of the safety valve, the front end of the first air passage 301 is communicated with the air passage between the safety valve and the oil-water separator 13, and the front end of the second air passage 302 is connected with the air outlet of the air storage cylinder 11.

The air reservoir 11 in the air handling unit is a dual-chamber air reservoir, including a left air chamber 111 and a right air chamber 112. The safety valve comprises two second hydraulic control check valves 14 with the front ends connected in parallel, the second hydraulic control check valves 14 can only enable gas to be transmitted from front to back, air inlets of the two second hydraulic control check valves 14 are connected with air outlets of the oil-water separator 13, an air outlet of one second hydraulic control check valve 14 is connected with an air inlet of the left air chamber 111, and an air outlet of the other second hydraulic control check valve 14 is connected with an air inlet of the right air chamber 112. The left air chamber 111 and the right air chamber 112 are respectively connected with two safety valves 15, so that the pressure of the left air chamber 111 and the right air chamber 112 can be ensured not to exceed rated values; the left air chamber 111 and the right air chamber 112 are also respectively connected with two water drain valves 16 to ensure that the interiors of the left air chamber 111 and the right air chamber 112 are dry. The front end of the second air channel 302 is respectively connected with the air outlets of the left air chamber 111 and the right air chamber 112.

The service brake unit comprises a foot brake valve 21, an air booster pump and a drive axle brake oil chamber, wherein the input end of the foot brake valve 21 is connected with the air outlet of the air storage cylinder 11, the output end of the foot brake valve is connected with the air inlet of the air booster pump, and the output end of the air booster pump is connected with the input end of the drive axle brake oil chamber. The left air chamber 111 and the right air chamber 112 are respectively connected with an air booster pump through a left air passage 24 and a right air passage 25, and 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 foot brake valve 21 is positioned at the left position, and a left air passage 24 and a right air passage 25 behind the foot brake valve 21 are communicated with the atmosphere through an air outlet of the foot brake valve 21 respectively, and the left air passage 24 and the right air passage 25 in front are closed; when the pedal of the foot brake valve 21 is depressed, the foot brake valve 21 is positioned at the right position, and the left air passage 24 and the right air passage 25 behind the foot brake valve 21 are respectively communicated with the left air passage 24 and the right air passage 25 in front of the foot brake valve 21 through two air inlets and air outlets, so that the air in the air passage in front of the foot brake valve 21 is transmitted to the air passage behind the foot brake valve from front to back.

A three-position controlled combined reversing valve 26 is arranged 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 positioned in the middle position, the left air passage 24 and the right air passage 25 at the rear of the combined reversing valve are respectively communicated with the left air passage 24 and the right air passage 25 at the front of the combined reversing valve, so that the gas in the left air passage 24 and the right air passage 25 at the front of the combined reversing valve 26 is respectively transmitted to the left air passage 24 and the right air passage 25 at the rear of the combined reversing valve from front to rear; when the combined reversing valve 26 is positioned at the left position, only the right air passage 25 at the rear of the combined reversing valve is communicated with the right air passage 25 at the front of the combined reversing valve, and only the air in the right air passage 25 at the front of the combined reversing valve 26 is transmitted to the right air passage 25 at the rear of the combined reversing valve from front to rear; when the combined reversing valve 26 is positioned at the right position, only the left air passage 24 at the rear of the combined reversing valve is communicated with the left air passage 24 at the front of the combined reversing valve, and only the air in the left air passage 24 at the front of the combined reversing valve 26 is transferred from front to rear into the left air passage 24 at the rear of the combined reversing valve.

The transaxle brake oil chambers include a left front transaxle brake oil chamber 231, a right front transaxle brake oil chamber 232, a left rear transaxle brake oil chamber 233, and a right rear transaxle brake oil chamber 234, and 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 are connected with 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 are connected with the output end of the rear air booster pump 272, and the left air passage 24 and the right air passage 25 behind the combined reversing valve 26 are respectively communicated with the air inlets of the front air booster pump 271 and the rear air booster pump 272. The left air path 24 and the right air path 25 are provided with a second one-way valve 28 which can only transmit the air from front to back at the junction near the air inlet of the front air booster pump 271 and the air inlet of the rear air booster pump 272 respectively.

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 which can only transmit the gas from front to back is arranged 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 communicated with the gas path between the oil-water separator and the first one-way valve 303.

As shown in fig. 2 and 3, in the parking and auxiliary brake unit, the one-way control valve 38 includes a valve body 3801, a left chamber 3802, a right chamber 3803, and an intermediate chamber 3804 that communicates the left chamber 3802 and the right chamber 3803 are provided in the valve body 3801. The left, right and middle chambers 3802, 3803, 3804 are all circular in cross-section and all coaxially disposed.

The right chamber 3803 is provided with a valve core 3806 which can move left and right and is matched with the right chamber 3803, the right side of the valve core 3806 is connected with the right side wall of the right chamber 3803 through a control valve return spring 3807, the right side surface of the valve core 3806 is provided with a groove 3815 which is coaxial with the valve core 3806, and the left end of the control valve return spring 3807 is fixedly connected with the left side surface of the groove 3815. A piston 3805 capable of moving left and right therein and adapted thereto is provided in the left chamber 3802, and the piston 3805 and the valve body 3806 are connected by a connecting rod 3808. The outer contours of the cross-sections of the piston 3805 and the valve core 3806 are circular to fit the left and right chambers 3802, 3803, respectively. The radius of the middle chamber 3804 is smaller than the radius of the left and right chambers 3802, 3803 such that the right end surface of the left chamber 3802 forms the right stop 3812 of the piston 3805 and the left end surface of the right chamber 3803 forms the left stop 3813 of the spool 3806.

The first channel 3809 communicated with the outside is formed in the circumferential side wall of the middle chamber 3804, the second channel 3810 communicated with the outside is formed in the circumferential side wall of the right part of the left chamber 3802, the control channel 3811 communicated with the outside is formed in the left side wall of the left chamber 3802, and the outer end of the control channel 3811 is connected with the second channel 3810, namely, the control channel 3811 is communicated 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, and the outer end of the second channel 3810 is connected to the second air channel 302 and the parking brake chamber 32 through three-way connectors respectively.

As shown in fig. 3, when the piston 3805 moves to the right to the far right, the spool 3806 is located at the far right end, and at this time, between the second passage 3810 and the intermediate chamber 3804 is closed by the piston 3805; as shown in fig. 2, when the piston 3805 moves leftwardly to the leftmost end, the spool 3806 is located at the leftwardmost end, and the second passage 3810 communicates with the intermediate chamber 3804 through the left chamber 3802; the first passage 3809 is always in communication with the intermediate chamber 3804. The connection of the right end surface and the outer side surface of the piston 3805 is chamfered or beveled to form an inclined surface 3814, and when the piston 3805 moves rightwards to the rightmost end, the inclined surface 3814 abuts against the right limiting table 3812. As shown in fig. 3, to ensure that the piston 3805 can thoroughly abut against the right stop 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.

In the present embodiment, it is set that the direction of the fluid such as the gas or the hydraulic oil flowing from the second passage 3810 to the first passage 3809 is the reverse direction from the rear to the front, and the direction of the fluid flowing from the first passage 3809 to the second passage 3810 is the forward direction from the front to the rear. The one-way control valve 38 is initially positioned with both the piston 3805 and the spool 3806 at the leftmost end.

When the fluid passes in the opposite direction, the fluid enters the second channel 3810 from the outer end of the second channel 3810, and 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, and reaches a pipeline or other component located in front of the one-way control valve 38 and connected to the outer end of the first channel 3809; another portion enters the left portion of the left chamber 3802 from the control passage 3811, squeezing the piston 3805 to move it to the right while compressing the control valve return spring 3807 on the right side of the spool 3806, the one-way control valve 38 interrupting the forward transfer of fluid as the fluid entering the left portion of the left chamber 3802 from the control passage 3811 squeezes the piston 3805 to the far right. That is, when fluid is transferred in the opposite direction, a small amount of fluid or fluid having a smaller pressure may enter the pipe or other components connected in front thereof through the one-way control valve 38, and when the fluid pressure increases to move the piston 3805 to the right-most end, the one-way control valve 38 stops the transfer of fluid from the rear to the front.

The sizes of the whole one-way control valve 38 and the parts can be designed and adjusted according to actual requirements, so that when the fluid is transferred in the opposite direction, the fluid pressure of the fluid to be cut off can move the piston 3805 to the rightmost end to disconnect the one-way control valve 38, the fluid not to be cut off can directly pass through the one-way control valve 38 in the opposite direction, and the sizes of the whole one-way control valve 38 and the parts are not limited in particular.

In the multifunctional braking system of engineering machinery disclosed by the utility model, compressed air is dried by an air compressor 12 of an engine through an oil-water separator 13, and then enters a left air chamber 111 and a right air chamber 112 of an air storage cylinder 11 through a safety valve formed by combining two second hydraulic control one-way valves 14.

As shown in fig. 1, when braking is required during running, the pedal of the foot brake valve 21 is depressed to enable the foot brake valve 21 to be in the right position, gas in the gas cylinder 11 sequentially passes through the foot brake valve 21 and the combined reversing valve 26 and enters right cavities of the front air booster pump 271 and the rear air booster pump 272, and brake fluid in left cavities of the front air booster pump 271 and the rear air booster pump 272 is pushed to be respectively pressed into 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, so that running braking is realized. Releasing the pedal of the foot brake valve 21, resetting the foot brake valve 21 and releasing the service brake.

As shown in fig. 1, in the driving process, under the action of a safety valve, high-pressure gas of an air compressor 12 of an engine is dried by an oil-water separator 13 and then directly enters a first air path 301, one gas on the first air path 301 enters a pressure detection end of a pressure switch 34 to enable the pressure switch 34 to be closed, at the moment, an automatic parking relay 36 is in contact attraction, a parking brake switch 35 is a normally closed switch, the parking relay 35 is in contact attraction, a coil of an electromagnetic valve 31 is electrified to enable the coil of the electromagnetic valve 31 to be positioned at a left position, and the other gas on the first air path 301 enters a parking brake air chamber 32 through an electromagnetic valve 31 and then enters a first hydraulic control check valve 310 to compress a right return spring, so that a gearbox brake 33 is in a disengaging state.

When the vehicle stops, the parking brake switch 37 is disconnected, the coil of the parking relay 35 is disconnected to disconnect the contacts of the parking brake switch, so that the coil of the electromagnetic valve 31 is disconnected, and the electromagnetic valve 31 is in the right position under the action of the right return spring of the electromagnetic valve, and as the air quantity in the left cavity of the parking brake air chamber 32 is small and the pressure is small, the air in the left cavity of the parking brake air chamber 32 can be directly discharged into the atmosphere through the electromagnetic valve 31 by the one-way control valve 38, and the right return spring of the parking brake air chamber 32 drives the gearbox brake 33 to act, so that normal parking brake is realized. Abnormal braking can also be achieved by closing the park brake switch 35 in the event of service brake failure.

In the event of an abnormal engine stall, the air compressor 12 of the engine is unable to continue to supply gas into the first air circuit 301, while still providing electricity in the system. At this time, the pressure switch 34 is turned off due to the decrease of the air pressure, the automatic parking relay 36 is powered off to disconnect the contacts, the parking relay 35 is powered off to disconnect the contacts, the coil of the electromagnetic valve 31 is powered off to be in the right position, the air in the left cavity of the parking brake chamber 32 is directly discharged into the atmosphere through the electromagnetic valve 31 by the one-way control valve 38, and the return spring on the right side of the parking brake chamber 32 drives the gearbox brake 33 to act, so that abnormal parking brake is realized.

When the vehicle needs to be carried under the abnormal flameout condition of the engine, the switch 39 is closed, and because more gas exists in the air storage cylinder 11 and the gas pressure is higher, and because of the arrangement of the safety valve in front of the air storage cylinder 11, the high-pressure gas in the air storage cylinder 11 can only enter the second gas path 302. The gas on the second gas path 302 enters the left part of the left chamber 3802 of the one-way control valve 38 from the outer end of the second gas path 3810 after passing through the three-way joint, the piston 3805 is extruded to move rightmost end and compresses the control valve return spring 3807, at this time, the inclined surface 3814 is abutted to the right limiting table 3812, the gas in the second gas path 3810 can not enter the middle chamber 3804 through the left chamber 3802 any more, and the one-way control valve 38 can stop the transmission of the gas from the second gas path 302 to the electromagnetic valve 31; the other way of gas enters the parking brake chamber 32 to compress the right return spring, so that the gearbox brake 33 is in a disengaged state, and the parking brake is released.

The foregoing is merely a preferred embodiment of the present utility model, and it should be noted that modifications and substitutions can be made by those skilled in the art without departing from the technical principles of the present utility model, and these modifications and substitutions should also be considered as being within the scope of the present utility model.

Claims (10)

1. The multifunctional braking system of the engineering machinery is characterized by comprising an air processing unit, a parking and auxiliary braking unit and a service braking unit connected with the air processing unit;

The parking and auxiliary braking unit comprises a two-position three-way electromagnetic valve (31), a parking braking air chamber (32) and a gearbox brake (33), and further comprises a normally open type pressure switch (34) and a normally closed type parking braking switch (37) which are connected in series, wherein the front end of the electromagnetic valve (31) is connected with an air treatment unit, the rear end of the electromagnetic valve is connected with an air inlet of the parking braking air chamber (32), the output end of the parking braking air chamber (32) is connected with the gearbox brake (33), the input end of the pressure switch (34) is connected with a power supply, the output end of the pressure switch is connected with the input end of the parking braking switch (37), the output end of the parking braking switch (37) is connected with the input end of a coil of the electromagnetic valve (31), the output end of the coil of the electromagnetic valve (31) is grounded, when the electromagnetic valve (31) is electrified, the air paths in front and behind the electromagnetic valve are connected, and when the electromagnetic valve (31) is powered off, the air paths in front are closed, and the air paths behind the electromagnetic valve are communicated with the atmosphere.

2. The multifunctional braking system of engineering machinery according to claim 1, wherein the front end of the electromagnetic valve (31) and the pressure detection end of the pressure switch (34) are connected in parallel and are connected with the air processing unit through a first air passage (301), the parking and auxiliary braking unit further comprises a one-way control valve (38) which can enable air to be transmitted forward and can stop air from flowing reversely by means of air pressure, and a first hydraulic control one-way valve (310) which can enable air to be transmitted forward and backward only and is connected with the one-way control valve (38) in parallel, the front end of the one-way control valve (38) and the front end of the first hydraulic control one-way valve (310) are connected with the rear end of the electromagnetic valve (31), the rear end of the first hydraulic control one-way valve is connected with the air inlet of the parking brake air chamber (32), the air passage connected with the one-way control valve (38) is also connected with the air processing unit through a second air passage (302), and a switch (39) for controlling the on-off of the second air passage (302).

3. The multifunctional braking system of engineering machinery according to claim 2, wherein the parking and auxiliary braking unit further comprises a normally open parking relay (35) and an automatic parking relay (36), wherein the input end of a contact of the parking relay (35) is connected with a positive electrode of a power supply, the output end of the contact of the parking relay is connected with the input end of a coil of the electromagnetic valve (31), the input end of the coil of the parking relay (35) is connected with the output end of the parking brake switch (37) and the output end of the coil is grounded, the input ends of the contact of the automatic parking relay (36) and the coil are respectively connected with the output ends of the power supply and the pressure switch (34), and the output ends of the contact of the automatic parking relay (36) and the coil are connected to the input end of the parking brake switch (37) in parallel.

4. The work machine multi-function braking system of claim 2, wherein the air handling unit comprises: air compressor (12), oil-water separator (13), gas receiver (11) and can only pass through the relief valve of gaseous from front to back, the gas outlet of air compressor (12) is connected to the air inlet of oil-water separator (13), the relief valve air inlet is connected to the gas outlet, the relief valve gas outlet is connected to the air inlet of gas receiver (11), gas circuit between first gas circuit (301) front end intercommunication relief valve and oil-water separator (13), gas receiver (11) gas outlet is connected to second gas circuit (302) front end.

5. The multifunctional braking system of engineering machinery according to claim 4, wherein the air storage cylinder (11) is a double-air-chamber air storage cylinder and comprises a left air chamber (111) and a right air chamber (112), the safety valve comprises two second hydraulic control one-way valves (14) with front ends connected in parallel, air inlets of the two second hydraulic control one-way valves (14) are connected with air outlets of the oil-water separator (13), an air outlet of one second hydraulic control one-way valve (14) is connected with an air inlet of the left air chamber (111), and an air outlet of the other second hydraulic control one-way valve (14) is connected with an air inlet of the right air chamber (112).

6. The multifunctional braking system of engineering machinery according to claim 2, characterized in that the service braking unit comprises a foot braking valve (21), an air booster pump and a drive axle braking oil chamber, the air treatment unit comprises an air storage cylinder (11), the input end of the foot braking valve (21) is connected with the air outlet of the air storage cylinder (11), the output end of the foot braking valve is connected with the air inlet of the air booster pump, and the output end of the air booster pump is connected with the input end of the drive axle braking oil chamber.

7. The multifunctional braking system of engineering machinery according to claim 6, wherein the air storage cylinder (11) is a double-air-chamber air storage cylinder and comprises a left air chamber (111) and a right air chamber (112), the left air chamber (111) and the right air chamber (112) are respectively connected with an air booster pump through a left air passage (24) and a right air passage (25), the foot brake valve (21) is a two-position control valve comprising two air inlets and four air outlets, when a pedal of the foot brake valve (21) is released, the left air passage (24) and the right air passage (25) behind the foot brake valve (21) are communicated with atmosphere, and the left air passage (24) and the right air passage (25) in front are all closed, and when the pedal of the foot brake valve (21) is stepped on, the left air passage (24) and the right air passage (25) behind the foot brake valve (21) are respectively communicated with the left air passage (24) and the right air passage (25) in front of the foot brake valve (21).

8. The multifunctional braking system of engineering machinery according to claim 7, wherein a three-position controlled combined reversing valve (26) is arranged on a gas passage behind the foot braking valve (21) and in front of the air booster pump, when the combined reversing valve (26) is located at the middle position, a left gas passage (24) and a right gas passage (25) behind the combined reversing valve are respectively communicated with the left gas passage (24) and the right gas passage (25) in front of the combined reversing valve, when the combined reversing valve (26) is located at the left position, only a right gas passage (25) behind the combined reversing valve is communicated with the right gas passage (25) in front of the combined reversing valve, and when the combined reversing valve (26) is located at the right position, only a left gas passage (24) behind the combined reversing valve is communicated with the left gas passage (24) in front of the combined reversing valve.

9. The multifunctional brake system of engineering machinery according to claim 8, wherein 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), 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 are connected with output ends of the front air booster pump (271), 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 are connected with output ends of the rear air booster pump (272), and a left air passage (24) and a right air passage (25) behind the combined reversing valve (26) are respectively communicated with air inlets of the front air booster pump (271) and the rear air booster pump (272).

10. A multi-function braking system for construction machinery according to claim 9, characterized in that the left air path (24) and the right air path (25) are provided with a second one-way valve (28) which enables only the transfer of air from front to back, respectively, near the air inlet of the front air booster pump (271) and the air inlet of the rear air booster pump (272).