CN111645474B - Auxiliary device for variable stiffness of truck leaf spring suspension - Google Patents

Abstract

Translated fromChinese

本发明公开了货车钢板弹簧悬架变刚度辅助装置，辅助空气弹簧的充气装置直接加装在现有的空气制动系统中，不需要单独设置供气管路，悬架改造成本低，辅助进气阀打开，则辅助空气弹簧的上表面与车架底部接触并紧贴，此时悬架的刚度由钢板弹簧和辅助空气弹簧并联构成，悬架整体刚度较大；与辅助空气弹簧连接的泄压阀打开放气，刚度减小，提高货车的乘坐舒适性和滤振性。

The invention discloses an auxiliary device for changing the stiffness of the leaf spring suspension of a truck. The inflating device of the auxiliary air spring is directly installed in the existing air brake system, without the need for a separate air supply pipeline, the suspension modification cost is low, and the auxiliary air intake is provided. When the valve is opened, the upper surface of the auxiliary air spring is in contact with the bottom of the frame and is in close contact. At this time, the stiffness of the suspension is formed by the parallel connection of the leaf spring and the auxiliary air spring, and the overall stiffness of the suspension is large; the pressure relief connected with the auxiliary air spring When the valve is opened and vented, the stiffness is reduced, which improves the ride comfort and vibration filtering of the truck.

Description

Variable-stiffness auxiliary device for truck leaf spring suspension

The application has the following application numbers: 201910794524.5, filing date: 2019-08-27, and the patent name of the invention patent of the auxiliary device for variable stiffness of the truck suspension and the control method.

Technical Field

The invention relates to the field of automobile safety, in particular to a variable stiffness auxiliary device for a leaf spring suspension of a truck.

Background

The truck suspension is an important component of the unmanned truck, and has the functions of transmitting force and torque acting between wheels and a frame, buffering impact force transmitted to the frame or a truck body from an uneven road surface, and attenuating vibration caused by the impact force so as to ensure that the truck can smoothly run. The suspension of the traditional truck mostly adopts a steel plate spring suspension, and the suspension is simple in structure, low in manufacturing cost and durable, so that the suspension is widely applied, but the rigidity of the suspension is difficult to adjust, and the change of the empty and heavy trucks of the truck cannot be well adapted, therefore, a main spring and auxiliary spring type spring is required to be designed, or auxiliary devices such as a load sensing proportional valve and the like are added to adjust the height and the rigidity of the suspension of the empty and heavy trucks, so that the suspension system is relatively complex, and even if the device is added, the steel plate spring still has the problems of poor comfort, poor vibration filtering performance and the like;

the suspension of present novel freight train is not simple leaf spring suspension, but adopts air suspension system, compares with traditional steel car suspension system, and air suspension has many advantages, and the most important one is the elastic coefficient of spring that the hardness of spring also can automatically regulated as required. The empty wagon and the heavy wagon of the wagon are changed greatly, the height of the wagon body of the wagon is adjusted by the air spring through the internal air pressure of the air spring, the height of the wagon body of the wagon under different wagon weights can be guaranteed to be consistent, passengers can take the wagon comfortably, the operation performance of the wagon is excellent, and the riding comfort of the passengers can be greatly improved, so that the air spring system is used for the newly-manufactured middle-large wagon at present.

However, many existing trucks still have a steel plate spring as a suspension due to an early delivery date, if the existing trucks are directly replaced by air springs, the refitting cost is high, the structures needing to be replaced are complex, and the air supply systems of the existing air spring devices are independently arranged, so that two sets of air supply systems are actually required to be installed on the trucks, and the other set of air supply systems is used for air braking, which also results in a large number of spare and accessory parts on the trucks and high cost.

Disclosure of Invention

The present invention aims to overcome the above-mentioned shortcomings and provide a technical solution to solve the above-mentioned problems.

The variable stiffness auxiliary device of the truck steel plate spring suspension is arranged on a truck chassis, a frame is arranged on the truck chassis, an axle is respectively arranged at the front part and the rear part of the truck chassis, wheels are arranged at the two ends of the axle, the front axle is a steering axle, the rear axle is a driving axle, and a steel plate spring and a shock absorber are arranged between the axle and a truck body;

the inner side of the steel plate spring and the axle are provided with auxiliary air springs, the bases of the auxiliary air springs are installed on the shell of the axle through bolts, the upper surfaces of the auxiliary air springs are in contact with the bottom of the vehicle body but are not connected, a gap is reserved between the upper surfaces of the auxiliary air springs and the bottom of the vehicle body when the air pressure in the auxiliary air springs is low, and the upper surfaces of the auxiliary air springs are in contact with the bottom of the vehicle body when the air pressure in the auxiliary air springs is high; the air outlet of the auxiliary air spring is communicated with the atmosphere through a pressure relief valve;

the air inlet of the auxiliary air spring is sequentially connected with an auxiliary air inlet pipe and the outlet of a pneumatic electromagnetic valve, the inlet of the pneumatic electromagnetic valve is connected with the outlet of the auxiliary air storage chamber, the auxiliary air storage chamber is also provided with two inlets and a pressure relief port, the pressure relief port is communicated with the atmosphere through a pressure relief valve, the two inlets are respectively connected with the outlet of a one-way valve, the inlet of the one-way valve is connected with one outlet of a two-position three-way electromagnetic valve, the inlets of the two three-way valves are respectively connected with the exhaust ports of the front relay valve and the rear relay valve, and the other outlet of the three-way valve is connected with the atmosphere; the air outlet of the front relay valve is connected with two drum membrane type brake subchambers of a front axle of the truck, and a push rod of the drum membrane type brake subchambers pushes brake shoes of a drum brake to form braking force; the air outlet of the subsequent brake valve is connected with two drum type brake subchambers of the truck rear axle, and a push rod of the drum type brake subchambers pushes brake shoes of a drum brake to form braking force; the air inlets of the front relay valve and the rear relay valve are respectively connected with one air outlet of the front air storage chamber and one air outlet of the rear air storage chamber; the inlet of each control air chamber of the front relay valve and the rear relay valve is respectively communicated with two air outlets of the main control valve, two air inlets arranged on the main control valve are respectively communicated with one air outlet of each front air storage chamber and one air outlet of each rear air storage chamber, and a valve body piston rod of the main control valve is connected with the brake pedal through a lever; the inlets of the front air storage chamber and the rear air storage chamber are respectively connected with the outlet of the air pump through the dryer and the air filter in sequence;

the manual control switches of the pneumatic electromagnetic valve, the two-position three-way electromagnetic valve and the pressure relief valve in the auxiliary air spring are respectively communicated with a manual switch or a knob or a handle or a pull rod arranged in the cab through pull wires.

Preferably, a distance sensor is connected to a wheel fender at the bottom of a frame of the truck or the corresponding position at the bottom of the frame in a bolt or buckle mode; the distance sensor detects the vertical distance between the wheel and the frame; an air flow sensor is arranged between the auxiliary air storage chamber and the pneumatic electromagnetic valve, and a pressure sensor is arranged between the outlet of the pneumatic electromagnetic valve and the air inlet of the auxiliary air spring;

the signal lines of the distance sensor, the air flow sensor and the pressure sensor are respectively connected with the signal input end of the controller, and the control signal lines of the pneumatic electromagnetic valve and the two-position three-way electromagnetic valve are respectively connected with the signal output end of the controller; the control lines of the two pressure release valves are respectively connected with the signal output end of the controller;

the distance sensor, the air flow sensor, the pressure sensor, the pneumatic electromagnetic valve, the pressure release valve, the two-position three-way electromagnetic valve and the controller are respectively connected with a storage battery through power lines directly or through a power adapter, and the storage battery is a 12V or 24V lithium ion storage battery or a starting storage battery for a truck engine.

Preferably, the distance sensor is an ARS410 millimeter wave radar, the working frequency of the distance sensor is 77GHz, and the effective sensing distance is 170 m; the air flow sensor is a dn15 vortex shedding flowmeter or an MF5706 air flow counter; the pressure sensor is an MIK-P300 diffused silicon pressure transmitter or an AS-131 diffused silicon pressure transmitter; the controller is an AT89C51 singlechip or an AT89C52 singlechip or other singlechips; the pneumatic electromagnetic valve is a positive Tai N2V025-08 two-position two-way DC24V electromagnetic valve or other types of two-position two-way electromagnetic valves; the two-position three-way electromagnetic valve is a Delwey 3V21008 two-position three-way electromagnetic valve or a VX33-15-08DC12V two-position three-way electromagnetic valve of a klqd company; the pressure release valve is an AR2002-02 type pressure release valve or an IR2000-02BG pneumatic high-precision pressure release valve.

Preferably, the front relay valve and the rear relay valve are balance pressurization relay valves of Dongfeng company or 140-type relay valves of Dongfeng company, and the main control valve is a release J6 manual control valve or a first-steam release Onwei brake master cylinder; the drum membrane type brake chamber is a brake chamber assembly of a brake cylinder spring of Ruili company or an Dongfeng 140 brake cylinder.

Compared with the prior art, the invention has the beneficial effects that: when the rigidity needs to be improved, the auxiliary air spring and the steel plate spring are used in parallel, when the suspension rigidity needs to be reduced, the auxiliary air spring is deflated, the inflation pipeline and the deflation pipeline of the auxiliary air spring are independently arranged, compressed air of the auxiliary air storage chamber comes from the existing air brake pipeline of the truck, the compressed air can be directly added and transformed on the existing truck air brake system, the transformation cost is low, the compressed air utilization rate of the air pump is high, and the economical efficiency is good.

Additional aspects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.

FIG. 1 is a schematic diagram of the connection between the pneumatic lines of the auxiliary device and the pneumatic lines of the truck brake in case one;

FIG. 2 is a schematic diagram of the connection between the pneumatic line of the auxiliary device and the pneumatic line of the truck brake in case two;

FIG. 3 is a schematic diagram of the operating principle of the main control valve;

FIG. 4 is an operational view of the open state of the forward relay valve;

FIG. 5 is a schematic diagram of the operation of the forward relay valve closure;

figure 6 is a schematic diagram of a truck suspension connection.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Referring to the variable stiffness auxiliary device of the truck leaf spring suspension shown in fig. 1-6, the auxiliary device is installed on a truck chassis, a frame 1 is installed on the truck chassis, anaxle 2 is respectively arranged at the front part and the rear part of the truck chassis, wheels 3 are arranged at two ends of theaxle 2, thefront axle 2 is a steering axle, therear axle 2 is a drive axle, and a leaf spring 4 and a shock absorber 5 are arranged between the axle 3 and a truck body;

anauxiliary air spring 12 is arranged on the inner side of the steel plate spring 4 and theaxle 2, the base of theauxiliary air spring 12 is installed on the shell of theaxle 2 through a bolt, the upper surface of theauxiliary air spring 12 is in contact with the bottom of the vehicle body but is not connected with the bottom of the vehicle body, a gap is reserved between the upper surface of theauxiliary air spring 12 and the bottom of the vehicle body when the air pressure in theauxiliary air spring 12 is low, and the upper surface of theauxiliary air spring 12 is in contact with the bottom of the; the air outlet of theauxiliary air spring 12 is communicated with the atmosphere through apressure relief valve 16;

an air inlet of theauxiliary air spring 12 is sequentially connected with an auxiliary air inlet pipe and an outlet of the pneumaticelectromagnetic valve 13, an inlet of the pneumaticelectromagnetic valve 13 is connected with an outlet of the auxiliaryair storage chamber 15, the auxiliaryair storage chamber 15 is further provided with two inlets and a pressure relief port, the pressure relief port is communicated with the atmosphere through apressure relief valve 16, the two inlets are respectively connected with an outlet of a one-way valve 14, an inlet of the one-way valve 14 is connected with an outlet of a two-position three-wayelectromagnetic valve 17, an inlet of one of the two-position three-wayelectromagnetic valves 17 is connected with an exhaust port of afront relay valve 18, an inlet of the other of the two-position three-wayelectromagnetic valves 17 is connected with an exhaust port of asubsequent relay valve 19, and the other outlet of the two-position three-wayelectromagnetic valve 17 is connected with the atmosphere; the air outlet of thefront relay valve 18 is connected with two drumtype brake subchambers 20 of a front axle of the truck, and a push rod of the drumtype brake subchambers 20 pushes brake shoes of a drum brake to form braking force; the air outlet of thesubsequent brake valve 19 is connected with two drumtype brake subchambers 20 of a rear axle of the truck, and a push rod of the drumtype brake subchambers 20 pushes brake shoes of a drum brake to form braking force; the air inlet of thefront relay valve 18 is respectively connected with one air outlet of each of the frontair storage chamber 23 and the rearair storage chamber 24, the air inlet of therear relay valve 19 is respectively connected with one air outlet of each of the frontair storage chamber 23 and the rearair storage chamber 24, the inlet of the control air chamber of thefront relay valve 18 is communicated with one of the two air outlets of themain control valve 21, and the inlet of the control air chamber of therear relay valve 19 is communicated with one of the two air outlets of themain control valve 21; one of the two air inlets arranged on themain control valve 21 is communicated with one air outlet of the frontair storage chamber 23, and one of the two air inlets arranged on themain control valve 21 is communicated with one air outlet of the rearair storage chamber 24;

a valve body piston rod of themain control valve 21 is connected with abrake pedal 22 through a lever; the inlets of the frontair storage chamber 23 and the rearair storage chamber 24 are respectively connected with the outlet of theair pump 8 through a drier 25 and anair filter 26 in sequence;

the first embodiment is as follows: in this embodiment, the manual control switches of thepneumatic solenoid valve 13, the two-position three-way solenoid valve 17, and therelief valve 16 in theauxiliary air spring 12 are respectively communicated with a manual switch provided in the cab via a pull wire. The above valve parts are all provided with a manual switch and a control line, so that a manual control mode can be adopted.

Therelay valve 18 and thesubsequent valve 19 are balance pressurization relay valves of Dongfeng company or 140 type relay valves of Dongfeng company, and themain control valve 21 is a release J6 manual control valve or a first-steam release Onwei brake master cylinder; the tympanic membranetype brake chamber 20 is a brake chamber assembly of a brake pump spring brake chamber of rui corporation or an east wind 140 brake pump.

The use method of the auxiliary device comprises the following steps: after the truck engine is started, theair pump 8 charges compressed air into the frontair storage chamber 23 and the rearair storage chamber 24, the frontair storage chamber 23 and the rearair storage chamber 24 are provided with pressure relief ports, the pressure relief ports are communicated with the atmosphere through pressure relief valves, when the truck is decelerated or stopped normally, thebrake pedal 22 is stepped down to push a piston rod in themain control valve 21 to move, as shown in fig. 3, the compressed air in the frontair storage chamber 23 and the rearair storage chamber 24 respectively enters the control air chambers of thefront relay valve 18 and therear relay valve 19 through themain control valve 21, as shown in fig. 4, thefront relay valve 18 and therear relay valve 19 are opened, the compressed air reaches the twobrake subchambers 20 arranged on the front axle through thefront relay valve 18, push rod actions in the brake subchambers drive a drum brake to complete a braking effect, the compressed air reaches the twobrake subchambers 20 arranged on the rear axle through the rearair storage chamber 24 and therear relay valve 19, the push rod in the brake chamber acts to drive the drum brake to act to complete the braking effect;

when thebrake pedal 22 is released, themain control valve 21 is closed, so that thefront relay valve 18 and therear relay valve 19 are closed, the compressed air remained in thefront relay valve 18 and therear relay valve 19 flows to the two-position three-wayelectromagnetic valve 17 and enters the auxiliaryair storage chamber 15 through the check valve 14, and the check valve 14 can ensure that the air in the auxiliaryair storage chamber 15 does not flow back when the pressure of the compressed air remained in thefront relay valve 18 and therear relay valve 19 is small; during braking, residual compressed air in thefront relay valve 18 and therear relay valve 19 flows into the auxiliaryair storage chamber 15 for storage, the use efficiency of the compressed air is improved, an additional air source device is not required to be provided for the auxiliary air spring, the structure is simplified, and the cost is low.

As shown in fig. 1, when the driver increases the vehicle speed or the load capacity is large, and the rigidity of the suspension is expected to be increased, thepneumatic solenoid valve 13 is manually controlled to be opened, so that the auxiliaryair storage chamber 15 inflates theauxiliary air spring 12, the upper surface of theauxiliary air spring 12 is contacted and attached to the bottom of the vehicle frame, the rigidity of the suspension is formed by connecting the steel plate spring and the auxiliary air spring in parallel, and the overall rigidity of the suspension is large; after one end of time of inflation, manually closing the pneumaticelectromagnetic valve 13, or when the pressure in theauxiliary air spring 12 is higher and thepressure release valve 16 connected with the pneumatic electromagnetic valve is automatically opened, closing the pneumaticelectromagnetic valve 13 after the driver hears the air leakage sound;

when the truck runs on a gravel road surface, in order to reduce vibration and bump, a driver controls apressure release valve 16 connected with theauxiliary air spring 12 to open and release air, so that the height of theauxiliary air spring 12 is reduced and the auxiliary air spring is separated from the bottom of a frame, at the moment, the rigidity of a suspension of the truck is only provided by a steel plate spring and is reduced to adapt to the gravel road surface, so that the rigidity of the steel plate spring can be reduced during the design of the truck, the riding comfort and the vibration filtering performance of the truck are improved, when the rigidity needs to be improved, the auxiliary air spring and the steel plate spring are used in parallel, an inflation pipeline of theauxiliary air spring 12 is independently arranged, compressed air of the auxiliaryair storage chamber 15 comes from an existing air brake pipeline of the truck, the increase and the transformation can be directly carried out on the existing truck air brake system, the transformation cost is low, and the cost is low.

Example two: when a driver manually controls the charging and discharging of theauxiliary air spring 12, the auxiliary air spring generally has two states, namely a full state and a fully-discharged state, and if the driver wants to adapt to more complicated road conditions, an electronic control device can be added;

the distance sensor 9 is connected to the wheel mudguard at the bottom of the frame of the truck or the corresponding position at the bottom of the frame in a bolt or buckle mode; the distance sensor 9 detects the vertical distance between the wheel 3 and the frame 1; an air flow sensor 10 is arranged between the auxiliaryair storage chamber 15 and the pneumaticelectromagnetic valve 13, and a pressure sensor 11 is arranged between the outlet of the pneumaticelectromagnetic valve 13 and the air inlet of theauxiliary air spring 12;

the signal lines of the distance sensor 9, the air flow sensor 10 and the pressure sensor 11 are respectively connected with the signal input end of thecontroller 30, and the control signal lines of the pneumaticelectromagnetic valve 13 and the two-position three-wayelectromagnetic valve 17 are respectively connected with the signal output end of thecontroller 30; the control lines of the twopressure release valves 16 are respectively connected with the signal output end of thecontroller 30;

the distance sensor 9, the air flow sensor 10, the pressure sensor 11, the pneumaticelectromagnetic valve 13, thepressure release valve 16, the two-position three-wayelectromagnetic valve 17 and thecontroller 30 are respectively connected with a storage battery through power lines directly or through a power adapter, and the storage battery is a 12V or 24V lithium ion storage battery or a starting storage battery for a truck engine.

The distance sensor 9 is an ARS410 millimeter wave radar, the working frequency of the distance sensor is 77GHz, and the effective sensing distance is 170 m; the air flow sensor 10 is a dn15 vortex shedding flowmeter or an MF5706 air flow counter; the pressure sensor 11 is an MIK-P300 diffused silicon pressure transmitter or an AS-131 diffused silicon pressure transmitter; thecontroller 30 is an AT89C51 singlechip or an AT89C52 singlechip or other singlechips; the pneumaticelectromagnetic valve 13 is a Zhengtai N2V025-08 two-position two-way DC24V electromagnetic valve or other types of two-position two-way electromagnetic valves; the two-position three-wayelectromagnetic valve 17 is a Delwey 3V21008 two-position three-way electromagnetic valve or a VX33-15-08DC12V two-position three-way electromagnetic valve of a klqd company; thepressure release valve 16 is an AR2002-02 type pressure release valve or an IR2000-02BG pneumatic high-precision pressure release valve; other types of sensors or solenoid valves may be used.

The control method of the auxiliary device comprises the following steps: thecontroller 30 receives the vertical distance H between the bottom of the frame and the wheels, which is acquired by the distance sensor 9, in real time within a certain time period T, calculates the minimum value Hmin and the maximum value Hmax of H within the T, sets H0 to Hmax-Hminx, extracts H0 of at least 2T, and then takes the average value H0ave of at least 2H 0, and if H0ave is greater than a certain threshold value H1, it is indicated that the vertical displacement of the truck suspension is large at this time, and the suspension stiffness needs to be improved, so that the suspension displacement is reduced, and the driving stability of the truck is improved; thecontroller 30 controls the pneumaticelectromagnetic valve 13 to open and inflate, so that the rigidity of theauxiliary air spring 12 is improved; if H0ave is smaller than a certain threshold H2, it indicates that the vertical displacement of the suspension is relatively small, which may cause the steel plate spring and the shock absorber in the suspension to be substantially inoperative, the damping effect is poor, and the riding comfort is poor, then thecontroller 30 controls the relief valve connected to theauxiliary air spring 12 to open, deflate theauxiliary air spring 12 to reduce the stiffness thereof, so that the steel plate spring and the shock absorber can work normally.

The better implementation mode is as follows: the signal input end of thecontroller 30 is also in communication connection with a pedal displacement sensor or a pedal angle sensor, and the pedal displacement sensor or the pedal angle sensor is arranged on a brake pedal and an accelerator pedal; the pedal displacement sensor can be a Milan KTM-100mm micro pull rod type linear displacement sensor or a displacement sensor with other signals, and the pedal angle sensor can be a WG9725570010 electronic pedal or a pedal angle sensor with other types;

when a driver steps on a brake pedal, a pedal displacement sensor or a pedal angle sensor sends a pedal displacement or an angle change value to thecontroller 30, and thecontroller 30 judges that when the brake pedal displacement or the angle change value is larger than a certain threshold value, twoauxiliary air springs 12 installed on an axle at the front part of the truck are inflated to increase the rigidity of a front suspension, and twoauxiliary air springs 12 installed on an axle at the rear part of the truck are deflated to reduce the rigidity of a rear suspension; therefore, the phenomenon of nodding of the truck during braking can be effectively inhibited.

When a driver steps on an accelerator pedal, a pedal displacement sensor or a pedal angle sensor sends a pedal displacement or an angle change value to thecontroller 30, and thecontroller 30 judges that when the accelerator pedal displacement or the angle change value is larger than a certain threshold value, twoauxiliary air springs 12 mounted on an axle at the front part of the truck are deflated, the rigidity of a front suspension is reduced, and twoauxiliary air springs 12 mounted on an axle at the rear part of the truck are inflated, so that the rigidity of a rear suspension is increased; therefore, the shaking phenomenon of the truck during acceleration can be effectively inhibited.

The better implementation mode is as follows: the signal input end of thecontroller 30 is also in communication connection with a gyroscope sensor arranged on the truck body, and the gyroscope sensor measures the steering angle of the truck body in the horizontal plane; the gyroscope sensor is a TL740D type gyroscope or a RisymENCE-03M single-axis gyroscope, when the steering angle is larger than a certain threshold value, which indicates that the truck is turning at the moment, twoauxiliary air springs 12 positioned on the inner side of the turning radius of the truck are deflated, and twoauxiliary air springs 12 positioned on the outer side of the turning radius of the truck are inflated; therefore, the centrifugal force applied to the truck during turning can be balanced, and the turning running stability of the truck is improved.

Claims (1)

1. The variable stiffness auxiliary device for the steel plate spring suspension of the truck is arranged on a truck chassis, a frame (1) is arranged above the truck chassis, an axle (2) is respectively arranged at the front part and the rear part of the truck chassis, wheels (3) are arranged at two ends of the axle (2), the front axle (2) is a steering axle, the rear axle (2) is a driving axle, and a steel plate spring (4) and a shock absorber (5) are arranged between the axle (2) and a truck body;

the method is characterized in that: an auxiliary air spring (12) is arranged on the inner side of the steel plate spring (4) and the axle (2), a base of the auxiliary air spring (12) is installed on a shell of the axle (2) through a bolt, a gap is reserved between the upper surface of the auxiliary air spring (12) and the bottom of a vehicle body when the air pressure in the auxiliary air spring is low, and the upper surface of the auxiliary air spring (12) is in contact with the bottom of the vehicle body when the air pressure in the auxiliary air spring (12) is high; the air outlet of the auxiliary air spring (12) is communicated with the atmosphere through a pressure relief valve (16);

an air inlet of an auxiliary air spring (12) is sequentially connected with an auxiliary air inlet pipe and an outlet of a pneumatic electromagnetic valve (13), an inlet of the pneumatic electromagnetic valve (13) is connected with an outlet of an auxiliary air storage chamber (15), the auxiliary air storage chamber (15) is also provided with two inlets and a pressure relief port, the pressure relief port is communicated with the atmosphere through a pressure relief valve (16), the two inlets are respectively connected with an outlet of a one-way valve (14), an inlet of the one-way valve (14) is connected with an outlet of a two-position three-way electromagnetic valve (17), an inlet of one of the two-position three-way electromagnetic valves (17) is connected with an exhaust port of a front relay valve (18), an inlet of the other of the two-position three-way electromagnetic valves (17) is connected with an exhaust port of a rear relay valve (19), and the other outlet of the two-position three-way electromagnetic valve (17) is connected with the atmosphere; an air outlet of the front relay valve (18) is connected with two drum membrane type brake subchambers (20) of a front axle of the truck, and a push rod of the drum membrane type brake subchambers (20) pushes brake shoes of a drum brake to form braking force; an air outlet of the subsequent brake valve (19) is connected with two drum membrane type brake subchambers (20) of the truck rear axle, and a push rod of the drum membrane type brake subchambers (20) pushes brake shoes of a drum brake to form braking force; an air inlet of the front relay valve (18) is respectively connected with one air outlet of the front air storage chamber (23) and one air outlet of the rear air storage chamber (24), an air inlet of the rear relay valve (19) is respectively connected with one air outlet of the front air storage chamber (23) and one air outlet of the rear air storage chamber (24), an inlet of a control air chamber of the front relay valve (18) is communicated with one of the two air outlets of the main control valve (21), and an inlet of the control air chamber of the rear relay valve (19) is communicated with one of the two air outlets of the main control valve (21); one of the two air inlets arranged on the main control valve (21) is communicated with one air outlet of the front air storage chamber (23), and one of the two air inlets arranged on the main control valve (21) is communicated with one air outlet of the rear air storage chamber (24); a valve body piston rod of the main control valve (21) is connected with a brake pedal (22) through a lever; the inlets of the front air storage chamber (23) and the rear air storage chamber (24) are respectively connected with the outlet of the air pump (8) through a drier (25) and an air filter (26) in sequence;

the manual control switches of the pneumatic electromagnetic valve (13), the two-position three-way electromagnetic valve (17) and the pressure release valve (16) connected with the auxiliary air spring (12) are respectively communicated with a manual switch arranged in the cab through pull wires;

a distance sensor (9) is arranged on a wheel fender at the bottom of a frame of the truck in a bolt or buckle mode; the distance sensor (9) detects the vertical distance between the wheel (3) and the frame (1); an air flow sensor (10) is arranged between the auxiliary air storage chamber (15) and the pneumatic electromagnetic valve (13), and a pressure sensor (11) is arranged between the outlet of the pneumatic electromagnetic valve (13) and the air inlet of the auxiliary air spring (12);

the signal lines of the distance sensor (9), the air flow sensor (10) and the pressure sensor (11) are respectively connected with the signal input end of the controller (30), and the control signal lines of the pneumatic electromagnetic valve (13) and the two-position three-way electromagnetic valve (17) are respectively connected with the signal output end of the controller (30); the control lines of the two pressure relief valves (16) are respectively connected with the signal output end of the controller (30);

the signal input end of the controller (30) is also in communication connection with a gyroscope sensor arranged on the truck body, and the gyroscope sensor is used for measuring the steering angle of the truck body in the horizontal plane;

the pneumatic electromagnetic valve (13) is a positive Tai N2V025-08 two-position two-way DC24V electromagnetic valve; the two-position three-way electromagnetic valve (17) is a Delwey 3V21008 two-position three-way electromagnetic valve or a VX33-15-08DC12V two-position three-way electromagnetic valve; the pressure release valve (16) is an AR2002-02 type pressure release valve or an IR2000-02BG pneumatic high-precision pressure release valve; the controller (30) is an AT89C51 singlechip, an AT89C52 singlechip or other singlechips; the gyroscope sensor is a TL740D type gyroscope or a Risym ENC-03M single-axis gyroscope.

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