阅读说明：本技术 一种悬浮式转向驱动桥、车辆以及其控制方法 (Suspension type steering drive axle, vehicle and control method thereof ) 是由 仪垂良 张成保 刘学峰 任东梅 孙绍华 孙盛刚 张翠英 高强 刘学串 于 2020-05-08 设计创作，主要内容包括：本公开涉及一种悬浮式转向驱动桥、车辆以及其控制方法,属于非道路农用车辆传动技术领域,该转向驱动桥包括驱动桥壳体总成、左摇臂总成以及右摇臂总成；左摇臂总成和分别铰接在驱动桥壳体总成的两端；还包括悬浮油缸和液压控制单元；在驱动桥壳体总成与摇臂总成的之间设有悬浮油缸；所述悬浮油缸可通过液压控制单元控制调节悬浮油缸实现摇臂总成的上下摆动。本公开的驱动桥、包含该驱动桥的车辆以及控制方法可以调节左右两侧悬浮油缸的支撑刚度以缓冲车辆的纵向、横向冲击颠簸,从而保持整机运行姿态的平稳。(The utility model relates to a suspension type steering drive axle, a vehicle and a control method thereof, belonging to the technical field of non-road agricultural vehicle transmission, wherein the steering drive axle comprises a drive axle housing assembly, a left rocker arm assembly and a right rocker arm assembly; the left rocker arm assembly is hinged to two ends of the drive axle housing assembly respectively; the hydraulic control system also comprises a suspension oil cylinder and a hydraulic control unit; a suspension oil cylinder is arranged between the driving axle housing assembly and the rocker arm assembly; the suspension oil cylinder can be controlled and adjusted by the hydraulic control unit to realize the up-and-down swing of the rocker arm assembly. The drive axle, the vehicle comprising the drive axle and the control method can adjust the support rigidity of the suspension oil cylinders at the left side and the right side to buffer longitudinal and transverse impact jolts of the vehicle, so that the stability of the running posture of the whole vehicle is kept.)

1. A suspension type steering drive axle comprises a drive axle housing assembly, a first rocker arm assembly and a second rocker arm assembly; the first rocker arm assembly and the second rocker arm assembly are respectively hinged at two ends of the drive axle housing assembly;

it is characterized by also comprising a suspension support oil cylinder and a hydraulic control unit; the suspension support oil cylinder is arranged between the drive axle housing assembly and the rocker arm assembly; the suspension support oil cylinder can control and adjust the flow and the flow direction of hydraulic oil in the oil cylinder through the hydraulic control unit to realize the up-and-down swing of the rocker arm assembly.

2. The suspension steering drive axle of claim 1, wherein the hydraulic control unit comprises a hydraulic valve group consisting of a proportional solenoid valve, a one-way throttle valve and an overflow valve; the hydraulic control unit controls the proportional solenoid valve to act according to the instruction and controls the hydraulic oil quantity entering and exiting the suspension support oil cylinder by superposing the throttling action of the one-way throttle valve.

3. The suspension steering drive axle of claim 1, further comprising an electronic control unit; the electric control unit comprises a microprocessor, a digital-to-analog converter, a power amplifier and a suspension height sensor; the suspension height sensor is configured to acquire suspension height change parameters when the wheels are impacted, the suspension height change parameters are processed by the digital-to-analog converter and then input into the microprocessor together with a CAN signal from a vehicle VCU, and the processed result of the microprocessor is amplified by the power amplifier and then output to the proportional solenoid valve of the hydraulic control unit to control the flow rate, the flow speed and the flow direction of hydraulic oil of the suspension support oil cylinder.

4. The suspension steering drive axle of claim 3, wherein the electronic control unit further comprises an operating mode switch; the working mode change-over switch is divided into three gears, the middle gear is a suspension opening mode, the handle is pushed to suspend in a middle locking mode, and the handle is pulled out to suspend in the lowest position.

5. The suspension type steering drive axle of claim 1, wherein the first rocker arm assembly and the second rocker arm assembly each comprise a first rocker arm, a second rocker arm, a knuckle, and a kingpin; the steering knuckle is connected with the rocker arm through a steering main pin, and the first rocker arm and the second rocker arm are connected with the driving axle housing through rotating shafts to form a four-bar mechanism; a height sensor is arranged on the rotating shaft; one end of the suspension support oil cylinder is supported on the drive axle shell, and the other end of the suspension support oil cylinder is supported on the second suspension rocker arm.

6. The suspension type steering drive axle of claim 1, wherein the drive axle housing assembly comprises a drive axle housing and a suspension cylinder support shaft disposed at an end of the housing; two ends of the drive axle shell are also provided with rotating shaft holes for connecting the rocker arm assemblies; the suspension cylinder is supported between the end of the transaxle case and the rocker arm of the rocker arm assembly.

7. The suspension steer drive axle of claim 1, further comprising a central drive assembly disposed within said drive axle housing assembly; the central transmission assembly comprises a central transmission driving gear, a central transmission driven gear and an automatic limited slip differential; the central transmission driving gear is fixed in the central transmission supporting seat and is meshed with the central transmission driven gear; the central transmission driven gear is fixed on the differential shell and is arranged in a differential fixing seat hole of the central transmission support together with the automatic limited slip differential.

8. The suspension type steering drive axle according to claim 1, wherein the drive axle further comprises a steering cylinder assembly, the steering cylinder assembly comprises a cylinder and a steering tie rod joint; the two ends of the oil cylinder are provided with piston rods, the piston rods are hinged with one end of a steering pull rod joint, the other end of the steering pull rod joint is connected with a steering knuckle arm on the rocker arm assembly to form a steering trapezoid, and the oil cylinder drives the left and right steering knuckle arms to deflect in a linkage manner when acting, so that a steering function is realized.

9. A vehicle comprising a suspension steer drive axle of any of claims 1 to 8.

10. A control method for a suspension type steering drive axle according to any one of the preceding claims 1 to 9:

feeding back information detected by a height sensor located on the rocker arm assembly to a digital-to-analog converter;

the signals converted by the digital-to-analog converter and the signals from the VCU of the whole machine are input into the microprocessor, are operated and then are amplified by the power amplifier, and then the proportional electromagnetic valve in the hydraulic control unit is driven to act to control the flow rate and the flow direction of the hydraulic oil flowing into the supporting oil cylinder so as to drive the rocker arm assembly to swing up and down.

Technical Field

The disclosure belongs to the technical field of non-road agricultural vehicle transmission, and particularly relates to a suspension type steering drive axle, a vehicle and a control method thereof.

Background

The statements herein merely provide background related to the present disclosure and may not necessarily constitute prior art.

The tractor as a main farmland operation power machine is widely popularized in agricultural production in China, has huge social reserves and provides powerful support for the modern development of agriculture. However, the development and manufacturing technology of the tractor in China has a large gap compared with the international advanced level for a long time, and the gap is larger particularly in the aspects of intellectualization, mechanical-electrical-hydraulic integration. The steering drive axle is used as an important power transmission part of the tractor, and has great influence on the comprehensive performance of the tractor, particularly the power performance, the passing performance and the comfort performance.

The inventor finds that the existing suspension type steering drive axle is still blank in the domestic tractor industry, four-wheel drive and large-scale trend are formed along with continuous expansion of functions of the tractor, but the technical level cannot meet the development requirement, the traditional rigid steering drive axle is still used for people, jolting vibration caused by the rigid axle in rough rural roads and field operation in vast rural areas seriously affects the operation quality and the operation efficiency of the tractor, and the physical health of a driver is seriously affected even, so that lumbar muscle strain, gastroptosis and the like are generated. With the development of agriculture and rural work, particularly the promotion of new rural construction, the production and living environment of farmers are greatly improved, people have higher requirements on the technical advancement of the agricultural machinery, and the research on the key technology of the suspension type steering drive axle is inevitable.

Disclosure of Invention

Aiming at the defects in the prior art, the invention provides a suspended steering drive axle, a vehicle and a control method thereof, which are applied to a four-wheel drive tractor to replace the current rigid steering drive axle and fill the domestic blank of the similar technology. When the tractor impacts wheels due to the change of running speed (including acceleration and deceleration working conditions) or the change of traction load (suddenly increasing or decreasing) or the unevenness of the ground, the intelligent controller controls the proportional valve and the one-way throttle valve of the hydraulic control module to act according to the signal strength fed back by the suspension displacement sensors arranged on the VCU and the suspension steering drive axle of the whole tractor, and adjusts the supporting rigidity of the suspension oil cylinders on the left side and the right side to buffer and absorb longitudinal and transverse impact jolts caused by the longitudinal and transverse impact jolts, so that the stability of the running posture of the whole tractor is maintained.

At least one embodiment of the present disclosure discloses a suspension-type steering drive axle, comprising a drive axle housing assembly, a first rocker arm assembly and a second rocker arm assembly; the first rocker arm assembly and the second rocker arm assembly are respectively hinged at two ends of the drive axle housing assembly; the hydraulic control system also comprises a suspension support oil cylinder and a hydraulic control unit; the suspension support oil cylinder is arranged between the drive axle housing assembly and the rocker arm assembly; the suspension support oil cylinder can control and adjust the flow and the flow direction of hydraulic oil in the oil cylinder through the hydraulic control unit to realize the up-and-down swing of the rocker arm assembly.

Further, the hydraulic control unit comprises a hydraulic valve group consisting of a proportional solenoid valve, a one-way throttle valve and an overflow valve; the hydraulic control unit controls the proportional solenoid valve to act according to the instruction and controls the hydraulic oil quantity entering and exiting the suspension support oil cylinder by superposing the throttling action of the one-way throttle valve.

Further, the drive axle further comprises an electric control unit; the electric control unit comprises a microprocessor, a digital-to-analog converter, a power amplifier and a suspension height sensor; the suspension height sensor is configured to acquire suspension height change parameters when the wheels are impacted, the suspension height change parameters are processed by the digital-to-analog converter and then input into the microprocessor together with a CAN signal from a vehicle VCU, and a result processed by the microprocessor is amplified by the power amplifier and then output to the proportional solenoid valve of the hydraulic control unit to control the flow rate, the flow speed and the flow direction of hydraulic oil.

Further, the electric control unit further comprises a working mode conversion switch; the working mode change-over switch is divided into three gears, the middle gear is a suspension opening mode, the handle is pushed to suspend in a middle locking mode, and the handle is pulled out to suspend in the lowest position.

Furthermore, the first rocker arm assembly and the second rocker arm assembly comprise a first rocker arm, a second rocker arm, a steering knuckle and a steering main pin; the steering knuckle is connected with the rocker arm through a steering main pin, and the first rocker arm and the second rocker arm are connected with the driving axle housing through rotating shafts to form a four-bar mechanism; a height sensor is arranged on the rotating shaft; one end of the suspension support oil cylinder is supported on the drive axle shell, and the other end of the suspension support oil cylinder is supported on the second rocker arm.

Further, the drive axle housing assembly comprises a drive axle housing and a suspension oil cylinder support shaft arranged at the end part of the drive axle housing; two ends of the drive axle shell are also provided with rotating shaft holes for connecting the rocker arm assemblies; the suspension cylinder is supported between the end of the transaxle case and the lower rocker arm of the rocker arm assembly.

Further, the drive axle also comprises a central transmission assembly arranged inside the drive axle housing assembly; the central transmission assembly comprises a central transmission driving gear, a central transmission driven gear and an automatic limited slip differential; the central transmission driving gear is fixed in the central transmission supporting seat and is meshed with the central transmission driven gear; the central transmission driven gear is fixed on the differential shell and is arranged in a differential fixing seat hole of the central transmission support together with the automatic limited slip differential.

Furthermore, the drive axle further comprises a steering oil cylinder assembly, wherein the steering oil cylinder assembly comprises an oil cylinder and a steering pull rod joint; the two ends of the oil cylinder are provided with piston rods, the piston rods are hinged with one end of a steering pull rod joint, the other end of the steering pull rod joint is connected with a steering knuckle arm on the rocker arm assembly to form a steering trapezoid, and the oil cylinder drives the left and right steering knuckle arms to deflect in a linkage manner when acting, so that a steering function is realized.

At least one embodiment of the present disclosure also discloses a vehicle including a suspended steer drive axle of any of the above.

At least one embodiment of the present disclosure further provides a control method for a suspension type steering drive axle based on any one of the above methods:

feeding back information detected by a height sensor located on the rocker arm assembly to a digital-to-analog converter;

the signals converted by the digital-to-analog converter and the signals from the VCU of the whole machine are input into the microprocessor, are operated and then are amplified by the power amplifier, and then the proportional electromagnetic valve in the hydraulic control unit is driven to act to control the flow rate and the flow direction of the hydraulic oil flowing into the supporting oil cylinder so as to drive the rocker arm assembly to swing up and down.

The embodiment disclosed above achieves the following advantages:

1. the suspension type steering drive axle disclosed by the invention realizes the elastic support that the left wheel and the right wheel connected with the steering drive axle of the tractor can independently act.

2. The suspension type steering drive axle wheel support rigidity realizes intelligent control, and changes along with the impact strength of the wheels and the change strength of the running speed of the whole machine in real time; the driving comfort is better than that of the traditional rigid steering drive axle model, and the field operation quality is improved.

4. This electronic control unit has set up three kinds of mode in floated steering drive axle for adapting to different operation operating mode, uses the suspension mode during the operation usually, and optional suspension closed mode or suspension fall to the spacing mode of machinery when adopting the operation of front suspension agricultural implement.

Drawings

The accompanying drawings, which are included to provide a further understanding of the disclosure, illustrate embodiments of the disclosure and together with the description serve to explain the disclosure and are not to limit the disclosure.

Figure 1 is a front view of a suspension steering drive axle provided by an embodiment of the present disclosure;

figure 2 is a top view of a suspension steer drive axle provided by embodiments of the present disclosure;

figure 3 is a left side view of a suspension steer drive axle provided by embodiments of the present disclosure;

figure 4 is a top view of a suspension steer drive axle provided by embodiments of the present disclosure;

FIG. 5 is a top view of a drive axle housing assembly provided by an embodiment of the present disclosure;

FIG. 6 is a front view of a drive axle housing assembly provided by an embodiment of the present disclosure;

FIG. 7 is a schematic structural diagram of a central transmission assembly provided by an embodiment of the present disclosure;

FIG. 8 is a schematic structural view of a left rocker arm assembly provided in an embodiment of the present disclosure;

FIG. 9 is a schematic structural diagram of a left rocker arm assembly mounting suspension support cylinder provided in the embodiment of the present disclosure;

FIG. 10 is a schematic structural diagram of a wheel hub reduction assembly provided by an embodiment of the present disclosure;

FIG. 11 is a schematic structural view of a steering cylinder assembly according to an embodiment of the present disclosure;

FIG. 12 is a system diagram of a hydraulic control unit provided by an embodiment of the present disclosure;

fig. 13 is a schematic view of an operating process of the electronic control unit according to the embodiment of the present disclosure.

In the figure: 1. a front central transmission assembly 111, a central transmission driving bevel gear 112, a central transmission driven bevel gear 113, an automatic limited slip differential 114, a central transmission support base 115, an automatic limited slip differential housing 2, a drive axle housing assembly 211, a drive axle housing 212, a swing axle front support base 213, a swing axle rear support base 214, a support cylinder pin 215, a rotating shaft hole 3, a wheel reduction assembly 311, a planet carrier 312, a bearing base 313, a universal transmission shaft assembly 4, a left suspension rocker arm assembly 411, an upper rocker arm 412, a lower rocker arm 413, a rotating shaft I, 414, a rotating shaft II, 415, a knuckle arm 5, a right suspension rocker arm assembly 6, a steering cylinder assembly 611, a cylinder 612, a piston rod 613, a piston rod joint 7, a hydraulic control unit 8, an electronic control unit 9, a suspension height sensor 10, a hydraulic control unit 5, a suspension height sensor, and a control system, A steering angular displacement sensor 11, a suspension support oil cylinder 12 and a hydraulic energy accumulator.

Detailed Description

It should be noted that the following detailed description is exemplary and is intended to provide further explanation of the disclosure. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs.

In the description of the present disclosure, it is to be understood that the terms "upper", "lower", "top", "bottom", "inner", "outer", and the like, indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, are only for convenience in describing the present disclosure and simplifying the description, and do not indicate or imply that the referred devices or elements must have a specific orientation, be constructed and operated in a specific orientation, and thus, should not be construed as limiting the present disclosure. Furthermore, the terms "first" and "second" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.

As shown in fig. 1-4, the intelligent control suspension type steering drive axle disclosed in this embodiment includes a front central transmission assembly 1, a drive axle housing assembly 2, a wheel hub reduction gear assembly 3, a left suspension rocker arm assembly 4, a right suspension rocker arm assembly 5, a steering cylinder assembly 6, a hydraulic control unit 7, and an electronic control unit 8. The front central transmission assembly 1 is arranged inside the drive axle housing assembly 2, the left and right suspension rocker arm assemblies are arranged at two ends of the drive axle housing assembly and are connected with the drive axle housing assembly through rotating shafts, the rotating shafts of the left and right upper suspension rocker arms are respectively provided with a suspension height sensor 9, a suspension support oil cylinder 11 is arranged between the drive axle housing and the lower suspension rocker arm, steering knuckles in the left and right suspension rocker arm assemblies are respectively connected with the left and right wheel-side reducer assemblies 3, and the wheel-side reducer directly drives steering drive wheels. When the vehicle runs on a rugged ground or the running speed of the vehicle changes (such as starting acceleration and braking deceleration), wheels can be impacted by different degrees, so that the suspension rocker arm can bounce up and down, the suspension height sensor 9 and the vehicle complete machine VCU transmit detection signals to the electric control unit 8, a controller in the electric control unit 8 processes the signals and then outputs and controls the hydraulic control unit 7 to act, and the flow, the flow speed and the flow direction of hydraulic oil entering and exiting the suspension support oil cylinder 11 are timely and accurately controlled by combining the energy accumulator 12 to change the support rigidity of the hydraulic oil to buffer and absorb bumping and vibrating energy, so that the unit can run stably.

As shown in fig. 5-6, the transaxle housing assembly 2 in this embodiment mainly includes a transaxle housing 211, a swing shaft front supporting seat 212, a swing shaft rear supporting seat 213, a supporting cylinder pin 214, and a central transmission assembly 1 disposed inside the transaxle housing, wherein two ends of the housing assembly are provided with a rotation shaft hole 215 for connecting a left rocker arm assembly, and the two rotation shaft holes are respectively connected with an upper rocker arm and a lower rocker arm in the left rocker arm assembly and the right rocker arm assembly through rotation shafts; the suspension support cylinder pin 214 is used for connecting with one end of the suspension support cylinder 11, and the other end of the suspension support cylinder 11 is fixed on the lower rocker arm in the rocker arm assembly.

Further, the front central transmission assembly 1 in the present embodiment as shown in fig. 7 includes a central transmission drive bevel gear 111, a central transmission driven bevel gear 112, an automatic limited slip differential 113, and a central transmission support 114. The central drive bevel gear 111 is mounted in a central drive carrier 114 using a pair of thrust bearings, and the central drive driven gear is bolted to the case 115 of the limited slip differential and mounted in a differential mount hole of the central drive carrier with a pair of thrust bearings along with the limited slip differential. The power is input through the central transmission driving gear to drive the central transmission driven gear to drive the automatic limited slip differential mechanism to rotate together, two half axle differential gears of the automatic limited slip differential mechanism are connected with a universal transmission shaft connected with left and right wheel reduction gears through splines to drive two steering driving wheels to work, specifically, the power from the transfer case is transmitted to the differential mechanism through the driven bevel gear, and then transmitted to the wheel reduction gears at the left and right ends through the left and right half axle gears and the universal transmission shaft in the differential mechanism to drive the front wheels to work. When the tractor moves straight, the hydraulic clutch inside the automatic limited slip differential combines to lock the differential gear of the two half shafts and the differential shell to rotate together, so that the two steering driving wheels can exert the best driving effect, and when the tractor steers, the steering angle displacement sensor 10 arranged at the steering knuckle on the left or right suspension rocker arm sends out a signal to automatically separate the hydraulic clutch to restore the differential function of the differential;

further, as shown in fig. 8-9, the rocker arm assembly in this embodiment is exemplified by a left suspension rocker arm assembly, which includes an upper rocker arm 411, a lower rocker arm 412, a knuckle, a suspension support cylinder, an upper steering kingpin, and a lower steering kingpin. Wherein, last rocking arm 411 is connected with the last shaft hole on the transaxle housing assembly 2 through pivot I413, and lower rocking arm 412 is connected with the lower shaft hole on the transaxle housing assembly 2 through pivot II414, and the knuckle is connected with upper and lower suspension rocking arm through upper and lower steering kingpin, and upper and lower suspension rocking arm forms four-bar linkage with the transaxle housing body coupling like this. One end of the suspension support cylinder 11 may be disposed directly in the lower rocker 412 and the other end is connected to the support cylinder pin 214 on the transaxle housing assembly 2. The connection mode of the right suspension rocker arm assembly is the same as that described above, and redundant description is omitted here.

In order to keep the wheel alignment posture and eliminate motion interference, the upper steering main pin and the lower steering main pin can be designed into a joint bearing structure. When the wheels are impacted or the ground supporting force is sensed to change, the suspension rocker arm assembly can swing up and down along with the expansion of the suspension oil cylinder, so that the running attitude of the whole machine is kept stable.

The wheel reduction assembly disclosed in this embodiment is used for connecting the wheels of a vehicle and is connected with the upper and lower suspension rocker arm assemblies at the same time, as shown in fig. 10, the wheel reduction assembly adopts a planetary reduction mechanism, and includes a planet carrier (hub) 311, a bearing block 312, a planetary gear, an inner gear ring connecting plate, and a universal transmission shaft assembly 313. The inner gear ring is fixed on a steering knuckle of the suspension rocker arm assembly through an inner gear ring connecting plate to serve as a fixed component of the planetary reduction mechanism, the planet carrier 311 serves as a wheel hub to serve as an output component, three planetary gears are uniformly distributed and mounted on the wheel hub, the planet carrier 311 and a bearing seat 312 share a set of bolt to be connected with a driving wheel, two sets of conical roller bearings are arranged in the wheel hub to be supported on the steering knuckle, one end of a universal transmission shaft 313, namely a sun gear (a driving component of the planetary reduction mechanism), penetrates through the steering knuckle to be meshed with the three planetary gears, and the other end of the universal transmission shaft is connected with an inner.

Further, the steering drive axle disclosed in the embodiment is further provided with a steering oil cylinder assembly 6; as shown in fig. 11, the steering cylinder assembly includes a cylinder 611, a piston rod 612, a piston rod joint 613 and a steering rod joint. The middle of the oil cylinder 611 is installed on the central transmission support seat, the piston rods 612 are symmetrically arranged, two ends of the piston rod 612 are hinged to the steering pull rod joint through the piston rod joint 613, a ball pin is arranged at the other end of the steering pull rod joint and connected with a steering knuckle arm 415 of a steering knuckle to form a steering trapezoid shown in figure 2, and the oil cylinder drives the left steering knuckle and the right steering knuckle to be linked and deflected to achieve a steering function.

Further, as shown in fig. 12, the hydraulic control unit in the present embodiment mainly includes accumulators 9.1 and 9.2, proportional solenoid valves 7.1 and 7.2, cross valve groups 8.1 and 8.2, solenoid ball valves 6.1 and 6.2, a relief valve 3, check valves 11.1 and 11.2, a check throttle valve 4, two-way throttle valves 11.1 and 11.2, a two-position three-way solenoid valve 2, a throttle hole 5, a shuttle valve 10, and left and right levitation support cylinders a and B.

Suspension control during tractor driving is performed by elements such as proportional solenoid valves 7.1 and 7.2, cross valve banks 8.1 and 8.2, and accumulators 9.1 and 9.2. In the suspension mode state, the two-position three-way electromagnetic valve 2 and the two-position two-way electromagnetic ball valve 6.1 or 6.2 lose power, and the proportional valves 7.1 and 7.2 are partially or completely opened. The energy accumulators 9.1 and 9.2 provide a shock absorber function for the tractor, when the suspension oil cylinders A and B are contracted due to stress when the front wheels are changed by ground impact load, hydraulic oil is pressed into the energy accumulators 9.1 and 9.2, when the suspension rebounds, the suspension oil cylinders A and B are expanded, the hydraulic oil flows out of the energy accumulators 9.1 and 9.2 for oil supplement, and the cross valve groups 8.1 and 8.2 provide a passive compression damping function. The two-position three-way electromagnetic valve 2 is a poppet valve and is used for controlling oil feeding of a system. When the tractor body is lifted, the two-position three-way electromagnetic valve 2, the two-position two-way electromagnetic ball valve 6.1 or 6.2 and the proportional valve 7.1 or 7.2 are electrified and opened, oil is fed into the large cavity of the suspension oil cylinder A or B, and the piston rod of the suspension oil cylinder A or B extends to lift the front part of the tractor; two-way throttle valves 1.1 and 1.2 are used to control the fuselage lift and descent speeds, respectively. When the bidirectional throttle valve 1.2 is opened, the gravity of the front part of the tractor acts on the suspension oil cylinder, namely, the suspension pressure oil liquid is forced to be discharged into an oil tank through the throttle valve by the gravity of the tractor, so that the suspension is lowered, and the front part of the tractor falls; the orifice 5 is used for generating a pressure difference between the high-pressure outlet pressure of the load-sensitive variable displacement pump and the load feedback pressure so as to control and activate the oil pump and ensure the normal flow output of the oil pump; the proportional solenoid valves 7.1 and 7.2 function to provide dynamically varying active compression damping; the safety overflow valve 3 is used for limiting the highest working pressure of the suspension loop and preventing the suspension system from being overloaded; the two-position two-way electromagnetic ball valves 6.1 and 6.2 are used for isolating the left and right suspension oil paths, so that the effective independent control of the suspension lifting, descending and other working modes is ensured, and the normal work is realized; the check valves 11.1 and 11.2 are used for isolating the left suspension oil circuit and the right suspension oil circuit, and ensure that the left suspension system and the right suspension system share one safety valve 3 and share one set of oil drainage oil circuit under the condition of meeting the independent control of related functions; the one-way throttle valve 4 has the function of controlling the falling speed of the suspension when the machine body falls electrically, so as to ensure the safe and stable action; the shuttle valve 10 is used for selecting, switching and controlling pressure signals of the complete machine lifting system and the suspension system LS.

As shown in fig. 13, the electronic control unit 8 in the steering drive axle disclosed in this embodiment includes a microprocessor, a digital-to-analog converter, a power amplifier, a power supply, a levitation height sensor, and a working mode switch. When the front wheel is impacted by rugged ground, the suspension rocker arm swings with the front wheel and the rear wheel, a suspension height sensor arranged at the shaft end of a rocker arm bearing feeds back a signal to a digital-to-analog converter, the impact of the speed change of the whole machine on the front wheel is provided by a VCU of the whole machine, the signal converted by the digital-to-analog converter and the signal from the VCU of the whole machine are input into a microprocessor, and the microprocessor operates and then amplifies the signal to a power amplifier, so that a proportional electromagnetic valve in a hydraulic control unit can be driven to act to control the flow rate and the flow direction of hydraulic oil flowing into a.

In addition, the electric control unit 8 further comprises a working mode change-over switch, one end of the switch is connected with the power supply module, the other end of the switch is directly connected to the digital-to-analog converter, the working mode change-over switch is divided into three gears, the middle gear is a suspension opening mode, the front wheel is in a suspension state in the mode, the operation posture of the whole machine can be automatically kept stable, the handle is in a suspension middle position locking mode, the oil cylinder is supported to be in a full-closed state in an oil inlet and outlet way in the mode, and the front wheel loses the suspension function. The handle is pulled out and is suspended at the lowest position, the mechanical limit is effective at the moment, the working mode of the vehicle can be switched under different walking environments by setting the three-gear switch, and the adaptability of the vehicle is improved.

Although the present disclosure has been described with reference to specific embodiments, it should be understood that the scope of the present disclosure is not limited thereto, and those skilled in the art will appreciate that various modifications and changes can be made without departing from the spirit and scope of the present disclosure.