CN113565161B - Hybrid static pressure bulldozer traveling system - Google Patents

Abstract

The invention relates to the technical field of static pressure bulldozers of engineering machinery, in particular to a hybrid power static pressure bulldozer traveling system which comprises a power component, a main pipeline, an execution output component, an air suction prevention component, a flushing valve and an overload prevention valve, wherein the output end of the power component is connected with a variable pump-motor, high-pressure oil in the main pipeline connected with the high-pressure oil output end of the variable pump-motor is divided into a plurality of branches, the execution output component, the air suction prevention component, the flushing valve and the overload prevention valve are all arranged on the corresponding branches, and the tail end of each branch is connected with the low-pressure oil end of the main pipeline. The permanent magnet synchronous motor and the walking variable are coaxially connected with the engine through the clutch, the clutch is disconnected when the output power is not high in the working state, the motor is directly driven by the battery to rotate, the walking or bulldozing action is realized, when high-power output is needed, the engine works, the motor is converted into the generator to charge the battery, and the energy conservation and the energy recovery are really realized.

Description

Hybrid static pressure bulldozer traveling system

Technical Field

The invention relates to the technical field of static pressure bulldozers of engineering machinery, in particular to a novel closed type volume loop for walking of a hybrid static pressure power bulldozer, and particularly relates to a walking system of the hybrid static pressure power bulldozer.

Background

The bulldozer is suitable for pushing, excavating, backfilling earthwork and other bulk cargo operations on the ground of roads, railways, mines, airports and the like, and is indispensable mechanical equipment for construction of national defense engineering, mine construction, urban and rural roads and the like and water conservancy construction and the like.

With the rapid advance of international cooperation construction business in China and the competitive pressure of overseas engineering machinery manufacturers, the requirements on the engineering machinery are not only large in quantity, but also quite high requirements on the technical level of the engineering machinery are put forward. With the combination of modern electronic technology, computer technology, communication technology, artificial intelligence technology, sensor technology and other high and new technologies, the traditional static pressure bulldozer is developing in the direction of energy conservation, emission reduction and energy recovery.

The traditional hydraulic walking system of the full-hydraulic bulldozer mainly uses an engine as power, when the full-hydraulic bulldozer walks, the engine mainly drives a walking pump, the hydraulic system drives a walking motor to perform final transmission, and finally, the crawler is driven to walk.

At present, the pure electric bulldozers are researched and developed in a practical way at home and abroad, some pure electric bulldozers are pushed to the market, and a lot of problems exist no matter the pure electric bulldozers are started to serve as power sources or motors serve as power sources: for example, when the vehicle is in a dozing working condition, the dozing resistance is large, the engine/motor usually works near the maximum torque, the pure electric motor is driven to drive the engine, the power of the engine is not strong, the dozing resistance is slightly small when the vehicle is backed or travels in a straight line, and the engine does not exert the optimal performance, so that the power loss is caused.

Therefore, the performance of the travel drive system and the travel control system of the all-hydraulic bulldozer is an important factor that affects the performance of the bulldozer, and determines the level of work productivity.

The running power element is used as a core component of the full-hydraulic bulldozer, so that the performance of a power source can be better matched according to the actual working condition, the extreme performance of an engine can be exerted, energy recovery, energy conservation and emission reduction can be realized, the labor intensity of operators can be reduced, and the economical efficiency and the dynamic performance of the bulldozer operation can be improved.

Therefore, the research on the hybrid full-hydraulic bulldozer has important practical significance.

Disclosure of Invention

In order to solve one of the technical problems, the invention adopts the technical scheme that: a hybrid power static pressure bulldozer running system comprises a power component, a main pipeline, an execution output component, a second anti-suction structure, a flushing valve and an anti-overload valve, wherein the output end of the power component is connected with a variable pump-motor, high-pressure oil in the main pipeline connected with the high-pressure oil output end of the variable pump-motor is divided into a plurality of branches, the execution output component, the second anti-suction structure, the flushing valve and the anti-overload valve are all arranged on the corresponding branches, and the tail end of each branch is connected with the low-pressure oil end of the main pipeline; and an oil supplementing unit is arranged on one side of the variable pump-motor.

The air suction prevention assembly has the following functions:

function 1: the valve is opened by the pressure at the outlet of the pump when the machine normally walks, and if the machine slips down the slope, the rotating speed of the motor exceeds the flow provided by the pump, and the pressure at the outlet of the pump is lost, the valve is closed to limit the speed.

Function 2: air suction prevention: when the load inertia is low and the impact load is relatively high (high-power bulldozing), the impact load can easily cause the instant reduction of the rotating speed of the motor, consequently, the pressure of the high-pressure side is instantly increased, the flow rate flowing out of the motor and entering the low-pressure side is reduced for a short time, even if the input flow rate of the oil supplementing pump is added, the flow rate is lower than the suction rate of the main pump, the suction of the low-pressure side is caused, and the suction prevention assembly can realize suction prevention.

The function of the overload prevention valve is as follows: when the system pressure is too high and exceeds a rated set value, the valve is opened and directly enters a low-pressure side, which is equivalent to an overflow valve.

Function of the flush valve: oil on the high-pressure low-pressure side of the closed loop circulates back and forth, so that the oil temperature of the system rises quickly, and the flushing valve can realize quick oil exchange of the closed system.

In any of the above schemes, preferably, the power component includes an engine and a permanent magnet synchronous motor, the engine and the permanent magnet synchronous motor are coaxially connected through a clutch, and both the engine and the permanent magnet synchronous motor can be used for driving the variable pump-motor, so as to realize closed loop motion.

In any of the above schemes, preferably, the execution output component includes a variable motor and a pump-motor secondary element which are coaxially connected, and corresponding oil ports of the variable motor and the pump-motor secondary element are respectively connected to a high pressure side and a low pressure side of the system through oil pipes.

The variable motor and the pump-motor secondary element are connected in series and are connected to the high-pressure side and the low-pressure side of the system at the same time, and the variable motor mainly plays a role in outputting torque and rotating speed.

The serial pump-motor secondary element can realize the flow regeneration function according to the adjustment of the swash plate, and when the load impact is met or the pressure on one side is high, the system is prevented from being sucked to be empty.

For example: when the pump-motor secondary element is used as a motor, high-pressure oil enters the second energy accumulator through the first check valve to stamp the second energy accumulator, when the pressure or the flow of the high-pressure side is insufficient, the electromagnetic switch valve is opened, and the energy of the second energy accumulator enters the hydraulic oil way system to stamp the hydraulic system.

When the pump-motor secondary element is used as a pump, the energy of the second energy accumulator enters a closed system through the electromagnetic switch valve 7, and at the moment, the variable displacement motor and the pump-motor jointly output large torque.

In any of the above schemes, preferably, the oil supplementing unit includes a fixed displacement pump coaxially connected to the variable displacement pump-motor, the fixed displacement pump is used as an oil supplementing pump, the oil supplementing pump is connected to a first energy accumulator through a pipeline, a pipeline with a filter and a first overflow valve is arranged on a pipeline between the first energy accumulator and the oil supplementing pump, and the other end of the pipeline is connected to a branch path where the second anti-cavitation structure is located.

The system is additionally provided with an oil supplementing pump, so that the air suction is avoided, and the system can be used as a pump-motor to realize oil path control and oil exchange; however, in consideration of increasing energy consumption, the first energy accumulator is added at the high-pressure port of the oil supplementing pump, so that when impact load occurs, the shortage of the flow of the oil supplementing pump is compensated, oil is supplied to the low-pressure side, and after the load is recovered to be normal, the oil supplementing pump is used for filling oil to the first energy accumulator.

In any of the above solutions, it is preferable that the anti-suck valve assembly includes a first anti-suck structure and a second anti-suck structure that are arranged in series on the corresponding branch.

In any of the above schemes, preferably, the first anti-suction structure includes a first anti-suction valve and a first one-way valve that are arranged in parallel.

In any of the above schemes, preferably, the second air-suction prevention structure includes a second air-suction prevention valve and a second one-way valve that are arranged in parallel, and the one-way flow direction of the second one-way valve is opposite to that of the first one-way valve.

In any of the above schemes, preferably, one side of the execution output component is connected with a second energy accumulator through a pipeline, the pipeline where the second energy accumulator is located is respectively connected to the main pipelines corresponding to the high-pressure side and the low-pressure side of the execution output component, a first one-way valve for energy storage at the high-pressure side and a second one-way valve for energy storage at the low-pressure side are respectively installed on the oil pipes for connecting the high-pressure side and the low-pressure side, and an electromagnetic switch valve is connected in series to the pipeline where the first one-way valve for energy storage at the high-pressure side is located.

In any of the above aspects, preferably, a second overflow valve is connected to the flush valve, and the second overflow valve is connected to an oil tank.

When the generator drives the pump to rotate, high-pressure oil is pumped out by the variable pump-motor and enters the variable motor and the high-pressure port of the secondary element of the pump-motor, so that the variable motor drives the final transmission to rotate, and the whole vehicle can move forwards and backwards by adjusting the inclination angle of the swash plate of the pump-motor.

High-pressure oil that the oil supply pump was beated out among the closed return circuit gets into closed return circuit through the filter, firstly, in order to prevent that the suction from appearing in the closed return circuit, secondly, change hot oil for closed system through the flushometer, when hydraulic system meets the impact, impact load leads to variable motor's rotational speed to reduce in the twinkling of an eye very easily, the pressure of high-pressure side risees in the twinkling of an eye, thereby flow short time from variable motor inflow low-pressure side reduces, even if the flow of oil supply pump input in addition, also be less than the suction volume of main pump, cause the low pressure side suction, prevent that the suction is prevented to empty first anti-suction valve and second and prevent the suction valve, can not only guarantee to avoid long-time negative pressure, also can guarantee to last malleation.

The variable motor and the pump-motor are connected in series and are connected to the high-pressure side and the low-pressure side of the system at the same time, the variable motor mainly plays a role in outputting torque and rotating speed to a bridge, the pump-motor connected in series can realize a flow regeneration function according to the adjustment of a swash plate, and when load impact is met or the pressure on one side is higher, the system is prevented from being sucked to be empty.

The novel closed loop is provided with a first check valve, an electromagnetic switch valve and a second energy accumulator, when a pump-motor secondary element is used as a motor, high-pressure oil enters the second energy accumulator through the first check valve at the moment to stamp the second energy accumulator, when the pressure of high-pressure side or the flow is insufficient, the first electromagnetic valve is opened, and the energy of the second energy accumulator enters a hydraulic system to stamp the hydraulic system.

When hydraulic system meets the impact, impact load leads to the rotational speed of motor to reduce in the twinkling of an eye very easily, and the pressure of high-pressure side risees in the twinkling of an eye to flow short time from the motor inflow low pressure side reduces, even if in addition the flow of moisturizing pump input, also is less than the inspiratory capacity of main pump, causes the low pressure side to inhale, prevents inhaling empty check valve here and can not only guarantee to avoid long-time negative pressure, also can guarantee to last the malleation.

Compared with the prior art, the invention has the following beneficial effects:

1. the permanent magnet synchronous motor and the walking variable are coaxially connected with the engine through the clutch, the clutch is disconnected when the output power is not high in the working state, the motor is directly driven by the battery to rotate, the walking or bulldozing action is realized, when high-power output is needed, the engine works, the motor is converted into the generator to charge the battery, and the energy conservation and the energy recovery are really realized.

2. The energy supply of the power source can be matched according to different working conditions, the on-off of the clutch is controlled to select the power source, the motor is used as a generator to charge a battery when the engine is in a working condition, the engine does not work when the motor is used, and the motor drives the pump to work, so that energy conservation and emission reduction are realized in a real sense when the power source element is used.

3. The hydraulic circuit can realize that the variable pump/motor is alternatively used according to the actual working condition in the walking process of the bulldozer.

Drawings

In order to more clearly illustrate the detailed description of the invention or the technical solutions in the prior art, the drawings that are needed in the detailed description of the invention or the prior art will be briefly described below. Throughout the drawings, like elements or components are generally identified by like reference numerals. In the drawings, elements or components are not necessarily drawn to scale.

FIG. 1 is a schematic view of a hybrid hydrostatic bulldozer travel system of the present invention.

FIG. 2 is a flow chart of the hydraulic control of the walking system of the hybrid hydrostatic bulldozer according to the present invention.

Fig. 3 is a flow chart showing the control of the travel of the hybrid hydrostatic bulldozer according to the present invention.

FIG. 4 is a flowchart illustrating the control procedure for the start-up of the hybrid static pressure bulldozer according to the present invention.

FIG. 5 is a flow chart for executing the braking process of the hybrid static-pressure bulldozer according to the present invention.

FIG. 6 is a flow chart of the brake control of the hybrid static pressure bulldozer according to the present invention.

In the figure, 1, a variable pump-motor; 2. a constant delivery pump; 3. a filter; 4. a first accumulator; 5. a second accumulator; 6. a first check valve; 7. an electromagnetic switch valve; 8. a variable displacement motor; 9. a pump-motor secondary; 10. an overload prevention valve; 11. a first anti-cavitation structure; 12. a second anti-cavitation structure; 13. a first overflow valve; 14. a permanent magnet synchronous motor; 15. a clutch; 16. a second check valve; 17. a second overflow valve; 18. a flush valve; 19. an engine.

Detailed Description

Embodiments of the present invention will be described in detail below with reference to the accompanying drawings. The following examples are only for illustrating the technical solutions of the present invention more clearly, and therefore are only examples, and the protection scope of the present invention is not limited thereby.

As shown in fig. 1-6, a hybrid static-pressure bulldozer traveling system comprises a power component, a main pipeline, an execution output component, a second anti-suction structure, a flushing valve 18 and an anti-overload valve 10, wherein the output end of the power component is connected with a variable pump-motor 1, high-pressure oil in the main pipeline connected with a high-pressure oil output end of the variable pump-motor 1 is divided into a plurality of branches, the execution output component, the second anti-suction structure, the flushing valve 18 and the anti-overload valve 10 are all installed on the corresponding branches, and the tail end of each branch is connected with a low-pressure oil end of the main pipeline; an oil supplementing unit is arranged on one side of the variable pump-motor 1.

The second air suction prevention structure has the following functions:

function 1: the valve is opened by the pressure at the outlet of the pump when the machine normally walks, and if the machine slips down the slope, the rotating speed of the motor exceeds the flow provided by the pump, and the pressure at the outlet of the pump is lost, the valve is closed to limit the speed.

Function 2: the suction-preventing pump is characterized in that when the load inertia is low and the impact load is relatively high (high-power bulldozing), the rotation speed of the motor is easily reduced instantaneously due to the impact load, so that the high-pressure side pressure is increased instantaneously, the flow of the fluid flowing out of the motor and entering the low-pressure side is reduced for a short time, and even if the input flow of the oil supplementing pump is added, the flow is lower than the suction amount of the main pump, and the low-pressure side suction is caused.

Function of the overload prevention valve 10: when the system pressure is too high and exceeds a rated set value, the valve is opened and directly enters a low-pressure side, which is equivalent to an overflow valve.

Function of the flush valve 18: the oil on the high-pressure low-pressure side of the closed loop circulates back and forth, so that the oil temperature of the system rises quickly, and the flushing valve 18 can realize quick oil exchange of the closed system.

In any of the above schemes, preferably, the power component includes an engine 19 and a permanent magnet synchronous machine 14, the engine 19 and the permanent magnet synchronous machine 14 are coaxially connected through a clutch 15, and both the engine 19 and the permanent magnet synchronous machine 14 can be used for driving the variable displacement pump-motor 1, so as to realize closed loop motion.

In any of the above schemes, preferably, the execution output component includes a variable motor 8 and a pump-motor secondary element 9 which are coaxially connected, corresponding oil ports of the variable motor 8 and the pump-motor secondary element 9 are respectively connected to a high pressure side and a low pressure side of the system through oil pipes, and the variable motor is used for outputting torque and rotating speed.

The variable motor 8 and the pump-motor secondary element 9 are connected in series and are connected to the high-pressure side and the low-pressure side of the system at the same time, and the variable motor mainly plays a role in outputting torque and rotating speed.

The series pump-motor secondary element 9 can realize the flow regeneration function according to the adjustment of the swash plate, and when the load impact is met or the pressure on one side is high, the system is prevented from being sucked to be empty.

For example: when the pump-motor secondary element 9 is used as a motor, high-pressure oil enters the second energy accumulator 5 through the first check valve to stamp the second energy accumulator 5, when the pressure or the flow of the high-pressure side is insufficient, the electromagnetic switch valve 7 is opened, and the energy of the second energy accumulator 5 enters the hydraulic oil circuit system to stamp the hydraulic system.

When the pump-motor secondary 9 is used as a pump, the energy of the second energy store 5 is fed into the closed system via the solenoid valve 7, and the variable displacement motor 8 and the pump-motor together output a high torque.

In any of the above schemes, preferably, the oil supplementing unit includes a fixed displacement pump 2 coaxially connected to the variable displacement pump-motor 1, the fixed displacement pump 2 is used as an oil supplementing pump, the oil supplementing pump is connected to a first energy accumulator 4 through a pipeline, a pipeline with a filter 3 and a first overflow valve 13 is arranged on a pipeline between the first energy accumulator 4 and the oil supplementing pump, and the other end of the pipeline is connected to a branch path where the second anti-cavitation structure is located.

The system is additionally provided with an oil supplementing pump, so that the air suction is avoided, and the system can be used as a pump-motor to realize oil path control and oil exchange; however, in consideration of increasing energy consumption, the first energy accumulator 4 is added at the high-pressure port of the oil supplementing pump, so that when impact load occurs, the shortage of the flow of the oil supplementing pump is compensated, oil is supplied to the low-pressure side, and after the load is recovered to be normal, the oil supplementing pump is used for filling oil to the first energy accumulator 4.

In any of the above solutions, it is preferable that the anti-suck-through valve assembly includes a first anti-suck-through structure 11 and a second anti-suck-through structure 12, which are arranged in series on the corresponding branch.

In any of the above schemes, it is preferable that the first anti-suck-through structure 11 includes a first anti-suck-through valve and a first one-way valve which are arranged in parallel with each other.

In any of the above schemes, it is preferable that the second air-entrainment preventing structure 12 includes a second air-entrainment preventing valve and a second one-way valve which are arranged in parallel, and the one-way flow direction of the second one-way valve is opposite to that of the first one-way valve.

In any of the above-described embodiments, it is preferable that a second accumulator 5 is connected to one side of the execution output member via a pipe, the pipe in which the second accumulator 5 is located is connected to the main pipe corresponding to the high-pressure side and the low-pressure side of the execution output member, a first check valve 6 for storing energy on the high-pressure side and a second check valve 16 for storing energy on the low-pressure side are installed in the oil pipe for connecting the high-pressure side and the low-pressure side, respectively, and an electromagnetic opening/closing valve 7 is connected in series to the pipe in which the first check valve 6 for storing energy on the high-pressure side is located.

In any of the above embodiments, it is preferable that a second relief valve 17 is connected to the flush valve 18, and the second relief valve 17 is connected to the tank.

When the generator drives the pump to rotate, high-pressure oil is pumped out by the variable pump-motor 1 and enters the variable motor 8 and the high-pressure port of the pump-motor secondary element 9, so that the variable motor 8 drives the final transmission to rotate, and the whole vehicle can move forwards and backwards by adjusting the inclination angle of the swash plate of the pump-motor.

High-pressure oil that the oil supply pump was beated out among the closed return circuit gets into the closed return circuit through filter 3, firstly, in order to prevent that the air suction from appearing in the closed return circuit, secondly, change hot oil for the closed system through flushometer 18, when hydraulic system meets the impact, the impact load leads to variable motor 8's rotational speed to reduce in the twinkling of an eye easily, the pressure of high-pressure side risees in the twinkling of an eye, thereby flow short time from variable motor 8 inflow low pressure side reduces, even if in addition the flow of oil supply pump input, also be less than the suction volume of main pump, cause the low pressure side air suction, prevent that the first air suction valve of preventing of air suction and second from preventing the air suction valve, can not only guarantee to avoid long-time negative pressure, also can guarantee to last malleation.

The variable motor 8 and the pump-motor are connected in series and are connected to the high-pressure side and the low-pressure side of the system at the same time, the variable motor mainly plays a role in outputting torque and rotating speed to a bridge, the pump-motor connected in series can realize a flow regeneration function according to the adjustment of a swash plate, and when load impact is met or the pressure on one side is higher, the system is prevented from being sucked to be empty.

A first check valve 6, an electromagnetic switch valve 7 and a second energy accumulator 5 are arranged in the novel closed loop, when a pump-motor secondary element 9 is used as a motor, high-pressure oil enters the second energy accumulator 5 through the first check valve 6 at the moment and stamps the second energy accumulator 5, when the pressure of high-pressure side or the flow is insufficient, the electromagnetic switch valve 7 is opened, and the energy of the second energy accumulator 5 enters a hydraulic system and stamps the hydraulic system.

When hydraulic system meets the impact, impact load leads to the rotational speed of motor to reduce in the twinkling of an eye very easily, and the pressure of high-pressure side risees in the twinkling of an eye to flow short time from the motor inflow low pressure side reduces, even if in addition the flow of moisturizing oil pump input, also is less than the inspiratory capacity of main pump, causes the low pressure side to inhale, and the check valve of preventing inhaling sky here can not only guarantee to avoid long-time negative pressure, also can guarantee to last the malleation.

The specific working principle is as follows:

when the control system program sets the static pressure bulldozer to start and brake, the engine 19 works, the clutch 15 is disconnected, the program controls the motor to start, the pump to work, and the bulldozer normally walks and realizes the relevant actions of the scraper knife after the bulldozer starts.

Two determination conditions are set in the conventional procedure according to the conventional settings:

the first judgment condition is that when the static pressure bulldozer realizes high-speed forward or backward movement, the power of the motor does not meet the running speed requirement of the bulldozer (especially a high-horsepower bulldozer), the engine 19 is ignited and started, the clutch 15 is closed, the engine 19 drives the motor to rotate and drives a pump-motor primary element to work, and the motor is used as a generator to charge a vehicle-mounted battery;

in the second judgment condition, when the traction force does not reach the set value during bulldozing, the engine 19 is stopped, the clutch 15 is disconnected, the motor drives the pump-motor to work to realize related actions and functions, when large resistance is met, the power of the motor cannot be reached, the engine 19 is ignited and started, and the clutch 15 is closed, the engine 19 drives the motor to rotate and drives a primary element of the pump-motor to work.

The hybrid power has the advantages of avoiding the power loss and fuel waste of the engine 19 caused by the start, braking and low-load work of the pure electric bulldozer when the pure engine 19 is used as a power source, and avoiding the limited power and charging time of the pure electric bulldozer. Therefore, the power of the engine 19 can be better matched according to actual working conditions, and meanwhile, the novel closed type traveling system adopts the pump-motor secondary element 9 and the first energy accumulator 4 and the second energy accumulator 5, so that the energy is further recycled.

The patent relates to a novel mixed static pressure power bull-dozer walking closed volume return circuit, whole hydraulic pressure walking hydraulic system overall arrangement does: the pump drives the motor to rotate, stepless speed change is achieved, the hydraulic circuit can achieve the effect that the variable pump/motor is alternately changed and used according to actual working conditions in the walking process of the bulldozer, and the flow regeneration and energy saving effects are achieved.

The novel closed volume loop is adopted, a pump-motor element is adopted as a power element, the pump-motor element can be used as a pump working condition and can also be used as a motor working condition, the pump can walk when the pump is in the pump working condition, and the flow regeneration can be realized when the motor is in the motor working condition.

The two power source elements are an engine 19 and a permanent magnet synchronous motor 14 (the engine 19), wherein the permanent magnet synchronous motor 14 (a generator) and a walking variable pump are coaxially connected with the engine 19 through a clutch 15, the clutch 15 is disconnected when the output power is not high in the working state, the motor is directly driven by a battery to rotate, the walking or bulldozing action is realized, when high-power output is needed, the engine 19 works, and the motor is converted into the generator to charge the battery, so that the energy conservation and the energy recovery are realized in a true sense.

The energy supply of the power source can be matched according to different working conditions, the on-off of the clutch 15 is controlled to select the power source, when the engine 19 is in the working condition, the motor is used as a generator and charges a battery, when the motor is used, the engine 19 does not work, and the motor drives the pump to work, so that energy conservation and emission reduction are realized in a real sense on the aspect of using power source elements.

Interpretation of related terms

The static pressure bulldozer is also called a full hydraulic bulldozer, and refers to a bulldozer which adopts a static pressure technology transmission technology, wherein the static pressure transmission is realized by directly transmitting power by using hydraulic oil, and the static pressure bulldozer mainly comprises the following components: the hydrostatic drive has the advantages of large transmission ratio, high transmission efficiency, stepless speed regulation and the like, is regarded as the mainstream development direction of the bulldozer in the future, and has the characteristics of stepless speed change, rapid acceleration, reversing, accurate steering control and the like, and the hydrostatic drive also enables the system arrangement to be more flexible because the hydrostatic drive is only dependent on the hydraulic pump and the hydraulic motor to carry out power transmission without a complex torque converter, a gearbox, a steering clutch 15 and a brake and can automatically adjust the speed and the power to match the changed load compared with the hydraulic type and mechanical type bulldozers in transmission.

Hybrid power: the hybrid power means that the bulldozer uses two modes of diesel drive and electric drive, and has the advantages that the bulldozer starts and stops or normally walks, the bulldozer is driven only by a motor when in low-power bulldozer, and the engine 19 does not work when the power does not reach a certain power, so that the engine 19 can be always kept in the optimal working state, the power performance is good, the emission is low, and the source of electric energy is the engine 19, and only refueling is needed.

Primary/secondary pump-motor: if the element (hydraulic pump) in the hydraulic system that converts mechanical energy into hydraulic energy is a primary element, the element (hydraulic motor/pump) that can convert hydraulic energy and mechanical energy into each other is a secondary element or a secondary element.

Prevent inhaling empty subassembly: the valve is opened by the pressure at the outlet of the pump when the machine normally walks, and if the machine slips down the slope, the rotating speed of the motor exceeds the flow provided by the pump, and the pressure at the outlet of the pump is lost, the valve is closed to limit the speed. The suction-preventing pump is characterized in that when the load inertia is low and the impact load is relatively high (high-power bulldozing), the impact load easily causes the rotating speed of the motor to be instantly reduced, so that the pressure of the high-pressure side is instantly increased, the flow flowing out of the motor and entering the low-pressure side is reduced for a short time, and even if the input flow of the oil supplementing pump is added, the flow is lower than the suction amount of the main pump, and the suction of the low-pressure side is caused.

The above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; while the invention has been described in detail and with reference to the foregoing embodiments, it will be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; the modifications or the substitutions do not cause the essence of the corresponding technical solutions to depart from the scope of the technical solutions of the embodiments of the present invention, and the technical solutions are all covered in the scope of the claims and the specification of the present invention; it will be apparent to those skilled in the art that any alternative modifications or variations to the embodiments of the present invention may be made without departing from the scope of the invention.

The present invention is not described in detail, but is known to those skilled in the art.

Claims (2)

1. The utility model provides a hybrid static pressure bull-dozer traveling system which characterized in that: the high-pressure oil in the main pipeline connected with the high-pressure oil output end of the variable pump-motor is divided into a plurality of branches, the execution output part, the air suction preventing assembly, the flushing valve and the overload preventing valve are all arranged on the corresponding branches, and the tail end of each branch is connected with the low-pressure oil end of the main pipeline; an oil supplementing unit is arranged on one side of the variable pump-motor;

the power part comprises an engine and a permanent magnet synchronous motor, the engine and the permanent magnet synchronous motor are coaxially connected through a clutch, and both the engine and the permanent magnet synchronous motor can be used for driving the variable pump-motor to realize closed loop motion;

the execution output part comprises a variable motor and a pump-motor secondary element which are coaxially connected, and corresponding oil ports of the variable motor and the pump-motor secondary element are respectively connected to a high-pressure side and a low-pressure side of the system through oil pipes;

the oil supplementing unit comprises a fixed displacement pump coaxially connected with the variable displacement pump and the motor, the fixed displacement pump is used as an oil supplementing pump, the oil supplementing pump is connected with a first energy accumulator through a pipeline, an oil way with a filter and a first overflow valve is arranged on the pipeline between the first energy accumulator and the oil supplementing pump, the other end of the oil way is connected to a branch road where the anti-suction component is located, and the oil supplementing pump is connected with an oil tank;

the anti-vacuum-absorption assembly comprises a first anti-vacuum-absorption structure and a second anti-vacuum-absorption structure which are arranged on the corresponding branch in series;

the first air suction preventing structure comprises a first air suction preventing valve and a first one-way valve which are mutually connected in parallel;

the second air suction preventing structure comprises a second air suction preventing valve and a second one-way valve which are arranged in parallel, and the one-way flowing directions of the second one-way valve and the first one-way valve are opposite;

one side of the execution output part is connected with a second energy accumulator through a pipeline, the pipeline where the second energy accumulator is located is respectively connected with main pipelines corresponding to the high-pressure side and the low-pressure side of the execution output part, an oil pipe for connecting the high-pressure side and the low-pressure side is respectively provided with a high-pressure side energy accumulation check valve and a low-pressure side energy accumulation check valve, and the pipeline where the high-pressure side energy accumulation check valve is located is connected with an electromagnetic switch valve in series;

the air suction preventing component has the following functions:

the valve is opened by the pressure at the outlet of the pump when the machine normally walks, and if the machine slips down the slope, the rotating speed of the motor exceeds the flow provided by the pump, and the pressure at the outlet of the pump loses, the valve is closed to limit the speed;

when the load inertia is low and the impact load is relatively high, the impact load can easily cause the rotating speed of the motor to be instantly reduced, so that the pressure of the high-pressure side is instantly increased, the flow flowing out of the motor and entering the low-pressure side is reduced for a short time, even if the input flow of the oil supplementing pump is added, the flow is lower than the suction volume of the main pump, the low-pressure side is sucked, and the anti-suction component can realize anti-suction;

the function of the overload prevention valve is as follows: when the system pressure is too high and exceeds a rated set value, the valve is opened and directly enters a low-pressure side, which is equivalent to an overflow valve;

function of the flush valve: oil on the high-pressure low-pressure side of the closed loop circulates back and forth, so that the oil temperature of the system rises quickly, and the flushing valve can realize quick oil exchange of the closed system;

the serial pump-motor secondary elements can realize the flow regeneration function according to the adjustment of the swash plate, and when the system is impacted by load or the pressure on one side is higher, the system is prevented from being sucked empty;

when the pump-motor secondary element is used as a motor, high-pressure oil enters the second energy accumulator through the first check valve to stamp the second energy accumulator, when the pressure or the flow of the high-pressure side is insufficient, the electromagnetic switch valve is opened, and the energy of the second energy accumulator enters the hydraulic oil way system to stamp the hydraulic system;

when the pump-motor secondary element is used as a pump, the energy of the second energy accumulator enters a closed system through the electromagnetic switch valve, and at the moment, the variable displacement motor and the pump-motor jointly output large torque;

high-pressure oil pumped by an oil supplementing pump in the closed loop enters the closed loop through a filter, firstly, the closed loop is prevented from being emptied, secondly, hot oil is replaced for the closed loop through a flushing valve, when a hydraulic system encounters impact, the impact load easily causes the instant reduction of the rotating speed of a variable motor, and the pressure of a high-pressure side is instantly increased, so that the flow flowing into a low-pressure side from the variable motor is reduced in a short time, even if the flow input by the oil supplementing pump is added, the flow is lower than the suction amount of a main pump, the low-pressure side is emptied, the first air-suction preventing valve and the second air-suction preventing valve can prevent emptying, not only long-time negative pressure can be ensured and avoided, but also continuous positive pressure can be ensured;

when hydraulic system meets the impact, impact load leads to the rotational speed of motor to reduce in the twinkling of an eye very easily, and the pressure of high-pressure side risees in the twinkling of an eye to flow short time from the motor inflow low pressure side reduces, even if in addition the flow of moisturizing pump input, also is less than the inspiratory capacity of main pump, causes the low pressure side to inhale, prevents inhaling empty check valve and can not only guarantee to avoid long-time negative pressure, also can guarantee to last the malleation.

2. A hybrid hydrostatic bulldozer running system according to claim 1, characterised in that: and the flushing valve is connected with a second overflow valve, and the second overflow valve is connected with an oil tank.

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