CN209776171U - Transmission system and land leveler - Google Patents

Abstract

the utility model relates to the technical field of vehicles, in particular to a transmission system and a land leveler, the transmission system comprises an engine, a hydraulic pump, a hydraulic motor, a clutch, a main reducing gear, a differential mechanism and two half shaft assemblies, the hydraulic pump is configured to be connected with the engine in a transmission way, two output ports of the hydraulic motor are respectively connected with two output ports of the hydraulic pump, the hydraulic motor and the hydraulic pump form a closed loop, one end of the clutch is connected with the hydraulic motor, the other end of the clutch is connected with the input end of the main reducing gear, the output end of the main reducing gear is connected with the differential mechanism, the differential mechanism is respectively connected with the two half shaft assemblies, the two half shaft assemblies are respectively used for driving front wheels at two ends of a front axle frame to rotate, compared with the prior art, the transmission system can drive the front wheels to rotate, the cost can be effectively reduced. The land scraper comprises the transmission system.

Description

Transmission system and land leveler

Technical Field

The utility model relates to the technical field of vehicles, especially, relate to a transmission system and leveler.

background

for engineering vehicles, such as a land scraper, a bulldozer and the like, the engineering vehicles are towed through a transmission system for operation.

Taking a land leveler as an example, when the land leveler performs leveling operation, a certain angle is formed between a scraper blade and the advancing direction of the whole machine so that materials in front of the scraper blade are in a rolling state, and the operation resistance of the scraper blade is reduced; the front material of the scraper knife has a certain lateral force to the whole machine, and in order to eliminate partial lateral force and reduce the sideslip phenomenon of the tires of the front axle, the tires of the front axle are generally operated to incline to offset partial sideslip force. In a narrow operation field, the turning radius can be further reduced through the steering of the front wheels and the inclination of the front wheels. Under the working conditions of slope operation or edge scraping, the front wheel inclination function can enable tires to be vertical to the horizontal plane, and the operation stability is enhanced, so that the front axle of the land leveler generally comprises three composite functions of front wheel steering, front wheel inclination and front axle swinging.

meanwhile, the working device is pushed by the traction force of the machine walking, in the prior art, most of the land levelers are driven by rear axle wheels, and the front axle only has a steering function and does not have the driving traction force. The maximum traction of the grader is determined only by the load of rear axle wheels and the adhesion coefficient, and the front axle load of the grader generally accounts for about 30% of the weight of the whole grader, so that about 30% of the traction of the grader is not exerted. And when the fine leveling operation working condition of the land leveler is carried out, the requirement on the road surface evenness is higher, the common rear wheel driving can form tracks on the leveled road surface due to the fact that the rear wheel driving torque is too large during fine leveling operation, the damage to the road surface evenness is caused, the front wheel independent driving mode avoids the phenomenon, under the front wheel independent driving mode, the rear wheel is in a neutral position, the whole machine is dragged by the front wheel, and the rear wheel cannot damage the road surface leveled by the road surface.

In order to meet the use requirements of the land leveler under different working conditions, a front wheel auxiliary driving system and a control scheme thereof are adopted in the prior art, one mode adopts a double-pump double-motor driving mode, a double-low-speed high-torque motor (or a motor plus a speed reducer) is added at two ends of a front axle, a hydraulic pump is added in the whole land leveler to realize front axle driving, and the traction force of the whole land leveler is improved. The double-pump and double-motor scheme can solve the problem that the rotation speed of a left motor and a right motor is unequal under certain conditions (such as slope operation) so that the straight running of the land leveler is difficult to guarantee, the discharge capacity of the double pumps can be adjusted and controlled to meet different flow and pressure requirements of the left front wheel and the right front wheel during turning, but in order to realize turning of wheels and control of different discharge capacities of the double pumps during articulated steering of the whole land leveler, a front wheel steering angle sensor and an articulated steering angle sensor are required to be added, the cost is relatively high, and the straight running, the differential speed, the steering control and the like are relatively complex.

The second scheme adopts a single-pump double-motor scheme, which is lower in cost compared with the double-pump plus double-motor scheme, but because the motors adopt a parallel connection mode, the problem that the straight running of the grader is difficult to ensure due to unequal rotating speeds of the left motor and the right motor when the loads of the left front wheel and the right front wheel are unequal is caused, meanwhile, the adhesion coefficient of the front wheel on one side is poor, when the skid occurs, the flow distribution of the motor on the skid side is over-speeding easily caused, and the wheel on the other side is not driven, so that the driving traction force is lost, when the wheel on the turning inner side is low in rotating speed, the wheel resistance is high, the rotating speed of the wheel on the turning outer side is high, the wheel resistance is low, the required flow is different, because the left motor and the right motor are connected in parallel, the pressure of the left motor and the right motor is the same, the differential speed of the left front wheel and, resulting in large cyclic power losses.

SUMMERY OF THE UTILITY MODEL

The utility model aims to provide a: the utility model provides a transmission system and leveler to solve among the prior art transmission system of engineering vehicle and adopt double pump double motor or single pump double motor to drive the front axle wheel and lead to the higher problem of expense.

In one aspect, the present invention provides a transmission system, which includes:

An engine;

A hydraulic pump configured to be in driving connection with the engine;

a hydraulic motor forming a closed circuit with the hydraulic pump;

the hydraulic motor is connected with one end of the clutch;

the clutch is connected with the input end of the main speed reducing mechanism;

the differential is connected with the output end of the main speed reducing mechanism;

And the two half shaft assemblies are connected with the differential mechanism and are respectively used for driving front wheels at two ends of the front axle frame to rotate.

as a preferable scheme of the transmission system, the transmission system further includes a gearbox in transmission connection with the engine, a transmission shaft connected with a first power take-off port of the gearbox, and a rear drive axle connected with the transmission shaft, the rear drive axle is used for driving a rear wheel to rotate, and the hydraulic pump is connected with a second power take-off port of the gearbox.

Preferably, the transmission system further comprises a parking brake, and the parking brake is used for braking the vehicle

for preventing or allowing power transmission between the propeller shaft and the drive rear axle.

As a preferable scheme of the transmission system, the front bridge frame is further provided with two wheel-side speed reducing mechanisms, the two half shaft assemblies are respectively connected with input ends of the two wheel-side speed reducing mechanisms, and output ends of the two wheel-side speed reducing mechanisms are respectively connected with the two front wheels.

As transmission system's preferred scheme, the semi-axis assembly includes differential half axle, coupling assembling and reduction gear semi-axis, the one end of differential half axle with differential mechanism connects, the other end of differential half axle with coupling assembling is articulated, coupling assembling with the one end of reduction gear semi-axis is articulated, the other end of reduction gear semi-axis with the input of wheel reduction mechanism is connected.

as a preferable scheme of the transmission system, the transmission system further includes a steering mechanism and a tilting mechanism both disposed on the front axle frame, the steering mechanism is configured to drive the front wheels to steer, and the tilting mechanism is configured to control the front wheels to tilt relative to the front axle frame.

Preferably, the main speed reducing mechanism and the clutch are integrated on the front axle frame.

As a preferable aspect of the transmission system, the hydraulic pump is a variable displacement pump, and the transmission system further includes a pump control unit for controlling an inclination angle of a swash plate of the variable displacement pump.

Preferably, the hydraulic motor is a variable displacement motor, and the transmission system further comprises a motor control unit for controlling the inclination angle of the swash plate of the variable displacement motor

On the other hand, the utility model provides a land scraper, including the transmission system in any one above-mentioned scheme.

The utility model has the advantages that:

The utility model provides a transmission system, this transmission system include engine, hydraulic pump, hydraulic motor, clutch, main reducing gear, differential mechanism and two semi-axis assemblies. The hydraulic pump is configured to be in transmission connection with the engine, two output ports of the hydraulic motor are respectively connected with two output ports of the hydraulic pump, the hydraulic motor and the hydraulic pump form a closed loop, one end of the clutch is connected with the hydraulic motor, the other end of the clutch is connected with the input end of the main speed reducing mechanism, the output end of the main speed reducing mechanism is connected with the differential mechanism, the differential mechanism is respectively connected with two half shaft assemblies, and the two half shaft assemblies are respectively used for driving front wheels at two ends of the front axle frame to rotate. Compared with the prior art, the transmission system can drive the front wheel to rotate through the hydraulic pump and the hydraulic motor, and cost can be effectively reduced.

drawings

fig. 1 is a schematic structural diagram of a transmission system according to an embodiment of the present invention;

FIG. 2 is a schematic structural diagram of a hydraulic system in a transmission system according to an embodiment of the present invention;

Fig. 3 is a first schematic structural diagram of a front axle according to an embodiment of the present invention;

fig. 4 is a second schematic structural view of the front axle in the embodiment of the present invention;

Fig. 5 is a third schematic structural view of the front axle in the embodiment of the present invention;

Fig. 6 is a schematic structural view of a grader in an embodiment of the present invention.

In the figure:

1. an engine; 2. a hydraulic pump; 3. a hydraulic motor; 4. a clutch; 5. a main speed reduction mechanism; 6. a differential mechanism;

7. A half shaft assembly; 71. a differential half shaft; 72. a left cross shaft; 73. a hinged fork; 74. a right cross shaft; 75. a half shaft of the speed reducer;

8. A front bridge frame; 9. a hub reduction mechanism; 10. a gearbox; 11. a drive shaft; 12. driving a rear axle; 13. a parking brake;

14. a first electro-hydraulic servo valve; 141. a first control terminal; 142. a second control terminal; 15. a first variable cylinder;

16. A second electro-hydraulic servo valve; 161. a third control terminal; 17. a second variable cylinder;

18. A flush valve; 19. flushing the overflow valve;

20. An oil replenishing pump; 21. a one-way valve assembly; 22. an oil-supplementing overflow valve; 23. a filter;

24. A third electro-hydraulic servo valve; 241. a fourth control terminal;

25. a left tilt frame; 26. a right tilt frame; 27. inclining the oil cylinder; 28. a tilt pull rod; 29. a left knuckle; 30. a right knuckle; 31. a left steering cylinder; 32. a right steering cylinder; 33. a steering tie rod.

Detailed Description

the technical solution of the present invention will be described clearly and completely with reference to the accompanying drawings, and obviously, the described embodiments are some, but not all embodiments of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative work belong to the protection scope of the present invention.

In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience of description and simplification of description, but do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus, should not be construed as limiting the present invention. Furthermore, 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. Wherein the terms "first position" and "second position" are two different positions.

In the description of the present invention, it is to be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meaning of the above terms in the present invention can be understood in specific cases to those skilled in the art.

referring to fig. 1 to 5, the present embodiment provides a transmission system, which includes an engine 1, a hydraulic pump 2, a hydraulic motor 3, a clutch 4, a main speed reducing mechanism 5, a differential 6 and two half-shaft assemblies 7. The hydraulic pump 2 is configured to be in transmission connection with the engine 1, the hydraulic motor 3 and the hydraulic pump 2 form a closed loop, one end of the clutch 4 is connected with the hydraulic motor 3, the other end of the clutch 4 is connected with the input end of the main speed reducing mechanism 5, the differential mechanism 6 is connected with the output end of the main speed reducing mechanism 5 and respectively connected with two half shaft assemblies 7, and the two half shaft assemblies 7 are respectively used for driving front wheels at two ends of a front bridge frame 8 to rotate.

In this embodiment, the engine 1 rotates to drive the hydraulic pump 2 to rotate, the hydraulic pump 2 drives the hydraulic motor 3 to rotate, the hydraulic motor 3 outputs power to the main speed reducing mechanism 5 through the clutch 4, the power is transmitted to the two half-shaft assemblies 7 through the differential mechanism 6 after being reduced by the main speed reducing mechanism 5, and the two half-shaft assemblies 7 drive the front wheel to rotate. The clutch 4 is used to control the transmission or disconnection of power between the hydraulic motor 3 and the final reduction mechanism 5. Therefore, the transmission system can drive the front wheels to rotate through the hydraulic pump 2 and the hydraulic motor 3, and cost can be effectively reduced.

The hydraulic pump 2 is a variable displacement pump, and the transmission system further comprises a pump control assembly, wherein the pump control assembly is used for controlling the inclination angle of a swash plate of the hydraulic pump 2, so that the displacement of the hydraulic pump 2 can be controlled. The pump control assembly comprises a first electro-hydraulic servo valve 14 and a first variable oil cylinder 15, the first electro-hydraulic servo valve 14 is used for controlling the piston rod of the first variable oil cylinder 15 to move, and the piston rod of the first variable oil cylinder 15 is connected with a swash plate of the variable pump.

Specifically, the control oil is accessed from an oil inlet of a first electro-hydraulic servo valve 14, two oil outlets of the first electro-hydraulic servo valve 14 are respectively connected with a first cavity and a second cavity of a first variable cylinder 15, and a piston rod of the first variable cylinder 15 is connected with a swash plate of the variable pump. A first control end 141 and a second control end 142 are respectively arranged at two ends of the first electro-hydraulic servo valve 14, and the first control end 141 and the second control end 142 are both electromagnetic relays; the first electro-hydraulic servo valve 14 includes three working positions, which are a first working position, a middle position and a second working position. When only the first control end 141 is electrified, the first electro-hydraulic servo valve 14 is positioned at a first working position, at the moment, oil is fed into the first cavity, and oil is discharged from the second cavity; when only the second control end 142 is electrified, the first electro-hydraulic servo valve 14 is located at a second working position, oil is drained from the first cavity at the moment, and oil is drained from the second cavity; when the first control end 141 and the second control end 142 are both de-energized, the first cavity and the second cavity are both drained, the first electro-hydraulic servo valve 14 is located at the middle position, and the variable displacement pump runs in no-load mode. When the first control end 141 is electrified, the variable pump rotates forwards, and when the second control end 142 is electrified, the variable pump rotates backwards, so that the electrification between the first control end 141 and the second control end 142 is switched, and the change of the oil pumping direction of the variable pump can be realized; by controlling the magnitude of the current of the first control end 141 or the second control end 142, the flow of hydraulic oil entering the first cavity or the second cavity of the variable piston through the oil inlet of the first electro-hydraulic servo valve 14 can be controlled, so that the inclination amplitude of the swash plate is controlled, and the displacement of the variable pump is adjusted.

It should be noted that in the present embodiment, when only the first control terminal 141 is powered, the hydraulic pump 2 drives the hydraulic motor 3 to rotate the front wheel forward, and when only the second control terminal 142 is powered, the hydraulic pump 2 drives the hydraulic motor 3 to rotate the front wheel backward.

the hydraulic motor 3 is a variable displacement motor, and the transmission system further comprises a motor control assembly for controlling the inclination angle of the swash plate of the hydraulic motor 3. The motor control assembly comprises a second electro-hydraulic servo valve 16 and a second variable oil cylinder 17, the second electro-hydraulic servo valve 16 is used for controlling the piston rod of the second variable oil cylinder 17 to extend or retract, and the piston rod of the second variable oil cylinder 17 is connected with the swash plate of the variable motor.

The second electro-hydraulic servo valve 16 and the second variable cylinder 17 may be configured to have the same structure as the first electro-hydraulic servo valve 14 and the first variable cylinder 15, respectively, and in this embodiment, the second electro-hydraulic servo valve 16 and the second variable cylinder 17 are configured to have different structures from the first electro-hydraulic servo valve 14 and the first variable cylinder 15, respectively. Specifically, the second electro-hydraulic servo valve 16 is a two-position three-way valve including an a working position and a B working position, the second variable cylinder 17 is provided with a rod chamber and a rodless chamber, a piston rod in the rod chamber is sleeved with a pressure spring, and the pressure spring is in a compressed state. The rod cavity is connected with an oil inlet pipeline, the rodless cavity is connected with an oil inlet of the second electro-hydraulic servo valve 16 through a pipeline, and two oil outlets of the second electro-hydraulic servo valve 16 are respectively communicated with the oil pan and the rod cavity. The second electro-hydraulic servo valve 16 is provided with a third control end 161, the third control end 161 is an electromagnetic relay, and the third control end 161 is used for controlling the valve core of the second electro-hydraulic servo valve 16 to switch between the working position a and the working position B. When the third control end 161 is de-energized, the second electro-hydraulic servo valve 16 is located at the working position a, at this time, the rodless cavity of the second variable cylinder 17 is communicated with the oil pan, and the piston rod of the second variable cylinder 17 moves from the direction of the rod cavity to the direction of the rodless cavity under the action of the pressure spring, so that the piston rod of the second variable cylinder 17 simultaneously drives the swash plate of the variable motor to rotate, thereby realizing the adjustment of the displacement of the variable motor. When the third control end 161 is powered on, the second electro-hydraulic servo valve 16 is located at the B working position, the rodless cavity of the second variable cylinder 17 is communicated with the oil inlet pipeline, because the acting area of the hydraulic oil and the piston in the rodless cavity is larger than that of the hydraulic oil and the piston in the rod cavity, under the action of the pressure difference, the piston slides to one side of the rod cavity and compresses the pressure spring, and the piston rod of the second variable cylinder 17 simultaneously drives the swash plate of the variable motor to rotate, so as to realize the adjustment of the displacement of the variable motor.

In this embodiment, the two ports of the variable displacement pump and the two ports of the variable displacement motor are respectively communicated through a first pipeline and a second pipeline, and a flush valve 18 and a flush overflow valve 19 connected with the flush valve 18 are further arranged between the first pipeline and the second pipeline. The flushing valve 18 is close to the variable motor, two A ports and B ports of the flushing valve 18 are communicated with the first pipeline and the second pipeline respectively, a P port of the flushing valve 18 is communicated with the flushing overflow valve 19, the flushing valve 18 is a three-position three-way valve, two signal oil ports are arranged on the flushing valve 18, the two signal oil ports are communicated with the first pipeline and the second pipeline respectively through pipelines, in the working output process of the variable motor, one of the first pipeline and the second pipeline is communicated with high-pressure hydraulic oil, the other one of the first pipeline and the second pipeline is communicated with low-pressure hydraulic oil, the valve core of the flushing valve 18 can be driven to move under the action of pressure difference, and the low-pressure oil can flow back to the oil pan through the flushing valve 18 and the.

A shuttle valve is further arranged between the first pipeline and the second pipeline, and an oil outlet of the shuttle valve is connected with an oil inlet of the second electro-hydraulic servo valve 16 through an oil inlet pipeline.

This transmission system still includes the oil supplementing pump 20 with the coaxial setting of variable pump, drives oil supplementing pump 20 through engine 1 and rotates, oil supplementing pump 20 with the oil pan be connected, oil supplementing pump 20 communicates through two check valve subassembly 21 and first pipeline and second pipeline respectively, and when the hydraulic oil in first pipeline (or second pipeline) was low pressure hydraulic oil, hydraulic oil was pumped into first pipeline (or second pipeline) through oil supplementing pump 20 and corresponding system check valve 21. The oil supplementing pump 20 is further connected with a filter 23, the filter 23 is connected with an oil inlet of the first electro-hydraulic servo valve 14, impurities in hydraulic oil can be filtered through the filter 23, the oil supplementing pump 20 is further connected with an oil supplementing overflow valve 22, and when the oil pressure in an oil supplementing pipeline is high, the hydraulic oil can overflow to an oil pan through the oil supplementing overflow valve 22.

In this embodiment, the clutch 4 may be a wet clutch, the clutch 4 is connected to the third electrohydraulic servo valve 24, hydraulic oil is controlled to enter the clutch 4 through the third electrohydraulic servo valve 24, and then a driving plate and a driven plate of the clutch 4 are controlled to be frictionally coupled to achieve torque transmission between the variable displacement motor and the main speed reduction mechanism 5. The third electro-hydraulic servo valve 24 is a two-position three-way valve, an oil inlet of the third electro-hydraulic servo valve 24 is connected with the filter 23 through a pipeline, two oil outlets of the third electro-hydraulic servo valve 24 are respectively connected with the clutch 4 and the oil pan, a fourth control end 241 is arranged on the third electro-hydraulic servo valve 24, the fourth control end 241 is an electromagnetic relay, when the fourth control end 241 is powered on, the third electro-hydraulic servo valve 24 controls hydraulic oil to enter the clutch 4, and when the fourth control end 241 is powered off, the third electro-hydraulic servo valve 24 controls hydraulic oil to enter the oil pan.

the final reduction mechanism 5 and the clutch 4 are integrated on the front axle 8. The rotating speed output by the variable motor is reduced through the main reducing mechanism 5, the main reducing mechanism 5 comprises a driving bevel gear and a driven bevel gear which are meshed with each other, the driving bevel gear is connected with the clutch 4, the driven bevel gear is fixedly connected with the differential mechanism 6, and a driving gear of the differential mechanism 6 is driven to rotate through the driven bevel gear. The differential 6 is prior art, and the structure thereof is not described in detail herein, and the differential 6 is arranged to facilitate the steering of the front wheels.

Referring to fig. 3 and 4, in the present embodiment, two wheel-side reduction mechanisms 9 are further disposed on the front axle frame 8, the two half-shaft assemblies 7 are respectively connected to input ends of the two wheel-side reduction mechanisms 9, and output ends of the two wheel-side reduction mechanisms 9 are respectively connected to wheels at two ends of the front axle frame 8. By providing the hub reduction mechanism 9, the driving torque to the front wheels can be further increased. Specifically, the half-shaft assembly 7 includes a differential half-shaft 71, a connecting assembly and a reducer half-shaft 75, the connecting assembly includes a left cross-shaft 72, an articulated fork 73 and a right cross-shaft 74, one end of the differential half-shaft 71 is connected with the differential 6, the other end of the differential half-shaft 71 is hinged to one end of the left cross-shaft 72, the other end of the left cross-shaft 72 is hinged to the articulated fork 73, the articulated fork 73 is hinged to one end of the right cross-shaft 74, the other end of the right cross-shaft 74 is hinged to one end of the reducer half-shaft 75, and the other end of the reducer half-shaft 75 is connected with an. And bearings and sealing rings are arranged on the front bridge frame 8 and positioned on two sides of the differential mechanism 6, and the differential mechanism half shaft 71 penetrates through the bearings and the sealing rings.

The hub reduction gear 9 comprises an inner ring carrier, a planet carrier assembly and a sun gear, the inner ring carrier is fixedly connected with a left steering knuckle 29 or a right steering knuckle 30 through a bolt, and an inner gear ring is arranged on the inner side of the inner ring carrier; the planet wheel on the planet carrier assembly is positioned in the inner gear ring and is meshed with the inner gear ring, and the sun wheel is meshed with the planet wheel and is connected with the half shaft 75 of the speed reducer through a spline. And a wheel side shell is fixedly arranged on the outer side of the planet carrier assembly and used for mounting a front wheel. Preferably, the reducer half-shaft 75 and the sun gear are integrally disposed.

the transmission system further comprises a tilting mechanism and a steering mechanism, wherein the tilting mechanism and the steering mechanism are arranged on the front bridge frame 8, the steering mechanism is used for driving the front wheels to steer, the tilting mechanism is used for controlling the front wheels to tilt relative to the front bridge frame 8, the tilting mechanism comprises a left tilting frame 25, a right tilting frame 26, a tilting oil cylinder 27 and a tilting pull rod 28, and the steering mechanism comprises a left steering knuckle 29, a right steering knuckle 30, a left steering oil cylinder 3431, a right steering oil cylinder 32 and a steering pull rod 33. The left inclined frame 25 and the right inclined frame 26 are respectively pivoted at two ends of the front bridge frame 8, the left inclined frame 25 and the right inclined frame 26 are both connected with an inclined pull rod 28, an inclined oil cylinder 27 is arranged on the front bridge frame 8 and is used for driving the left inclined frame 25 or the right inclined frame 26 to rotate relative to the front frame 8, a right steering knuckle 30 is pivoted on the right inclined frame 26, a left steering knuckle 29 is pivoted on the left inclined frame 25, the left steering knuckle 29 and the right steering knuckle 30 are respectively pivoted with two ends of a steering pull rod 33, the left steering knuckle 29 is further hinged with an output end of a left steering oil cylinder 3431, a body end of the left steering oil cylinder 3431 is hinged with the front bridge frame 8, the right steering knuckle 30 is further hinged with an output end of a right steering oil cylinder 32, and a body end of the right steering oil cylinder 32 is hinged with the front bridge frame 8. The left knuckle 29 and the right knuckle 30 are also connected to the two wheel reduction mechanisms 9, respectively.

In this embodiment, the two ends of the tilt rod 28 are respectively hinged to the left tilt frame 25 and the right tilt frame 26. Four through holes with axes on the same plane are arranged on the left inclined frame 25 and the right inclined frame 26, wherein two through holes are arranged at intervals along the vertical direction, and the other two through holes are arranged at intervals along the front-back direction. The left steering knuckle 29 and the left inclined frame 25 are pivoted with two through holes in the vertical direction through pin shafts, and the right steering knuckle 30 and the right inclined frame 26 are pivoted with two through holes in the vertical direction through pin shafts; the two through holes in the front-back direction of the left inclined frame 25 and the two through holes in the front-back direction of the right inclined frame 26 are pivoted with the front frame 8 through pin shafts.

In the embodiment, the left steering oil cylinder 3431 and the right steering oil cylinder 32 are used for controlling the left steering knuckle 29 and the right steering knuckle 30 to drive the front wheels to rotate, the left inclined frame 25 or the right inclined frame 26 is driven by the inclined oil cylinder 27, the two steering knuckles are driven to incline synchronously by the inclined pull rod 28, and the synchronous inclination of the front wheels at the two ends of the front bridge frame 8 is finally realized, so that when the transmission system is used for a land leveler, partial side force applied to the whole machine by materials in front of a scraper knife can be eliminated, and the sideslip phenomenon of the front wheels is reduced; meanwhile, under the working conditions of slope operation or edge scraping, the front wheels can be perpendicular to the horizontal plane by controlling the inclination of the front wheels, so that the operation stability is enhanced.

In this embodiment, the left knuckle 29 and the right knuckle 30 are both provided with a bearing and a sealing ring, and the two reducer half shafts 75 are respectively inserted into the corresponding bearing and sealing ring on the knuckle and connected with the corresponding hub reduction mechanism 9 through splines.

The transmission system further comprises a gearbox 10, a transmission shaft 11 connected with a first power take-off port of the gearbox 10, and a rear drive axle 12 connected with the transmission shaft 11, wherein the rear drive axle 12 is used for driving rear wheels to rotate, and the hydraulic pump 2 is connected with a second power take-off port of the gearbox 10. The transmission system further comprises a parking brake 13, which parking brake 13 is used to prevent or allow power transmission between the propeller shaft 11 and the drive rear axle 12. The rear drive axle 12 and the parking brake 13 are both in the prior art, and the structure thereof is not described herein again, wherein the specific structure of the rear drive axle 12 is set according to the rear drive axle of the slewing bearing grader disclosed in the earlier patent with the application number CN 201620360528.4.

In this embodiment, the transmission case 10 is not limited to being directly connected to the engine 1 through a torque converter or an elastic coupling, and a transfer case may be provided between the engine 1 and the transmission case 10. Accordingly, the hydraulic pump 2 is not limited to be mounted at the power take-off of the transmission case 10, and may be mounted at the power take-off of the transfer case.

The transmission system further includes a selector switch that can be used to select a drive mode, including a forward drive mode, a rear drive mode, and a full drive mode.

In a default working mode, the selector switch is located at the position of the rear wheel driving mode, the fourth control end 241 is de-energized, hydraulic oil combined with the control clutch 4 is drained through the third electro-hydraulic servo valve 24, the clutch 4 enables the driving end and the driven end to be separated under the action of a spring, the transmission of the variable motor and the main speed reducing mechanism 5 is disconnected, the first control valve 141 and the second control valve 142 are simultaneously de-energized, the variable pump and the variable motor idle run, and the oil supplementing pump 20 provides oil supplementing for the low-pressure side in the first pipeline or the second pipeline and flushes the high-pressure side. The torque of the engine 1 is transmitted to a rear drive axle 12 through a gearbox 10 and a transmission shaft 11, so as to drive the rear wheels to rotate forwards, and a rear wheel drive mode is formed.

When the selector switch selects the front wheel drive mode, the transmission 10 is in a neutral gear, the fourth control end 241 is powered, the oil supplementing pump 20 provides control hydraulic oil to flow to the clutch 4 through the third electro-hydraulic servo valve 24, the spring of the clutch 4 is compressed to enable the driving end and the driven end to be in friction combination, so that the variable motor is in transmission combination with the main speed reducing mechanism 5, the first control end 141 and the third control end 161 are powered, and the output torque of the variable motor is transmitted to the two front wheels through the main speed reducing mechanism 5, the differential mechanism 6, the two half shaft assemblies 7 and the two wheel-side speed reducing mechanisms 9 respectively to form the front wheel drive mode. When the front wheels are steered or the loads of the two front wheels are unequal, such as slope operation, the rotating speeds of the two front wheels are unequal, and the differential speed of the two front wheels can be automatically realized through the differential mechanism 6.

When the selector switch selects the all-wheel drive mode, the fourth control end 241 is powered on, the control hydraulic oil provided by the oil supplementing pump 20 flows to the clutch 4 through the third electro-hydraulic servo valve 24, the spring of the clutch 4 is compressed to enable the driving end and the driven end to be in friction combination, so that the variable motor is in transmission combination with the main speed reducing mechanism 5, the first control end 141 and the third control end 161 are powered on, one part of the power of the engine 1 is converted through the variable pump and is output through the variable motor, the part of the power is respectively transmitted to the two front wheels through the main speed reducing mechanism 5, the differential 6, the two half-shaft assemblies 7 and the two wheel-side speed reducing mechanisms 9, and the other part of the power of the engine 1 is transmitted to the drive rear axle 12 through the gearbox 10 and the transmission shaft 11 to further drive the rear wheels to rotate. When the front wheels are steered or the loads of the two front wheels are unequal, such as slope operation, the rotating speeds of the two front wheels are unequal, and the differential speed of the two front wheels can be automatically realized through the differential mechanism 6.

It should be noted that when the selection switch selects the front wheel driving mode or selects the all wheel driving mode, the first control terminal 141 is turned off and the second control terminal 142 is turned on when a reverse operation is required.

the transmission system further comprises a forerunner speed adjusting knob, the forerunner speed can be adjusted through the forerunner speed adjusting knob, specifically, a forerunner speed set value set by the forerunner speed adjusting knob is read through a controller, the controller obtains current values of the first control end 141 and the third control end 161 according to a relationship map between the forerunner speed preset in the controller and current values of the first control end 141 and the third control end 161, and controls the current values of the first control end 141 and the third control end 161 to change, so that the displacement of the hydraulic system is changed, and the adjustment of the front wheel driving speed is realized.

Referring to fig. 6, the present embodiment further provides a motor grader, including the transmission system in the above solution.

it is obvious that the above embodiments of the present invention are only examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. Other variations and modifications will be apparent to persons skilled in the art in light of the above description. And are neither required nor exhaustive of all embodiments. Any modification, equivalent replacement, and improvement made within the spirit and principle of the present invention should be included in the protection scope of the claims of the present invention.

Claims (10)

1. A transmission system, comprising:

An engine (1);

A hydraulic pump (2) configured to be in driving connection with the engine (1);

A hydraulic motor (3) that forms a closed circuit with the hydraulic pump (2);

The clutch (4), the said hydraulic motor (3) is connected with one end of the said clutch (4);

The clutch (4) is connected with the input end of the main speed reducing mechanism (5);

The differential (6) is connected with the output end of the main speed reducing mechanism (5);

and the two half shaft assemblies (7) are connected with the differential (6), and the two half shaft assemblies (7) are respectively used for driving front wheels at two ends of the front bridge (8) to rotate.

2. the transmission system according to claim 1, further comprising a gearbox (10) in transmission connection with the engine (1), a transmission shaft (11) connected with a first power take-off of the gearbox (10), and a rear drive axle (12) connected with the transmission shaft (11), wherein the rear drive axle (12) is used for driving a rear wheel to rotate, and the hydraulic pump (2) is connected with a second power take-off of the gearbox (10).

3. A transmission system according to claim 2, characterized in that the transmission system further comprises a parking brake (13), the parking brake (13) being adapted to prevent or allow power transmission between the drive shaft (11) and the drive rear axle (12).

4. The transmission system according to claim 1, wherein two hub reduction gears (9) are further arranged on the front axle frame (8), two half-shaft assemblies (7) are respectively connected with input ends of the two hub reduction gears (9), and output ends of the two hub reduction gears (9) are respectively connected with two front wheels.

5. A transmission system according to claim 4, characterised in that the half-shaft assembly (7) comprises a differential half-shaft (71), a connecting assembly and a reducer half-shaft (75), one end of the differential half-shaft (71) being connected to the differential (6), the other end of the differential half-shaft (71) being articulated to the connecting assembly, the connecting assembly being articulated to one end of the reducer half-shaft (75), the other end of the reducer half-shaft (75) being connected to the input of the wheel reduction mechanism (9).

6. A transmission system according to claim 4, further comprising a steering mechanism for steering the front wheels and a tilting mechanism for controlling the tilting of the front wheels relative to the front axle (8), both provided on the front axle (8).

7. A transmission system according to claim 1, characterised in that the main reduction mechanism (5) and the clutch (4) are both integrated on the front axle (8).

8. A transmission system according to claim 1, wherein the hydraulic pump (2) is a variable displacement pump, the transmission system further comprising a pump control assembly for controlling the inclination angle of a swash plate of the variable displacement pump.

9. a transmission system according to claim 1, wherein the hydraulic motor (3) is a variable displacement motor, the transmission system further comprising a motor control assembly for controlling the angle of inclination of a swash plate of the variable displacement motor.

10. A grader comprising the drive system of any of claims 1-9.