CN104554432B - Engineering machine steer-by-wire system - Google Patents
Engineering machine steer-by-wire system Download PDFInfo
- Publication number
- CN104554432B CN104554432B CN201410230604.5A CN201410230604A CN104554432B CN 104554432 B CN104554432 B CN 104554432B CN 201410230604 A CN201410230604 A CN 201410230604A CN 104554432 B CN104554432 B CN 104554432B
- Authority
- CN
- China
- Prior art keywords
- valve
- engineering machinery
- oil
- steering
- steering system
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
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Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
- B62D—MOTOR VEHICLES; TRAILERS
- B62D5/00—Power-assisted or power-driven steering
- B62D5/06—Power-assisted or power-driven steering fluid, i.e. using a pressurised fluid for most or all the force required for steering a vehicle
- B62D5/09—Power-assisted or power-driven steering fluid, i.e. using a pressurised fluid for most or all the force required for steering a vehicle characterised by means for actuating valves
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
- B62D—MOTOR VEHICLES; TRAILERS
- B62D5/00—Power-assisted or power-driven steering
- B62D5/06—Power-assisted or power-driven steering fluid, i.e. using a pressurised fluid for most or all the force required for steering a vehicle
Abstract
The invention provides an engineering machine steer-by-wire system and relates to a steering system which is applied to an engineering machine and can effectively save energy. The novel engineering machine steer-by-wire system mainly comprises a steering wheel, an angular displacement sensor, a force feedback motor, an ECU (Electric Control Unit), an energy accumulator, an electromagnetic on/off valve, a proportional three-way valve, a variable oil cylinder, a variable pump, an electromagnetic reversing valve, a check valve, a shuttle valve, a hydraulic control check valve, a steering oil cylinder, an overflowing valve, a displacement sensor L and a pressure sensor P. The invention designs the steer-by-wire system aiming at the disadvantages of an existing engineering machine constant displacement pump type steering system that the oil consumption is high; the working environment of a cab is bad; a driver easily feels tired, and the steering is not sensitive and the like; an oil supplying source adopts the variable pump and a manner of controlling the variable pump by the proportional three-way valve is adopted in a steering hydraulic system; the movement of a steering hydraulic cylinder is controlled by sufficiently utilizing the properties of variable displacement of the variable pump and the steering is realized; the system has better energy conservation property and controllability.
Description
Technical field
The present invention relates to a kind of New engineering machinery wire-controlled steering system, particularly one kind are applied in engineering machinery effectively
The steering of energy-conservation.
Background technology
With the development of hydraulic pressure and electronic technology in engineering machinery field, riving condition and work of the people to engineering machinery
More and more higher is required, the product that can be significantly reduced driver's labour intensity and reduce energy resource consumption is just more prone to win city
；Traditional engineering machinery steering mainly realizes turning for engineering machinery using the linkage of hydraulic steering gear and flux amplification valve
To this turning facilities mechanically and hydraulically connect complexity, troublesome poeration, therefore operate light, simple structure, high working efficiency
Construction machinery product become market in the urgent need to.
Driver turns now to need to realize following process in driving engineering mechanical solid：Operator steering wheel turns
To, steering gear action control flux amplification valve break-make and direction, constant displacement pump output fluid control steering cylinder stretches.Due to system
Using constant displacement pump, system throttles and spill losses are very big.
Engineering machinery steering common on the market at present uses the structure such as Fig. 1, and its structure includes that 1- is quantitative
Pump, 2- pressure-gradient control valves, 3- hydraulic steering gears, 4- steering cylinders, 5- flux amplification valves are constituted.Steering wheel is turned to when not rotating
The port closing of device, guide's fluid flows back to fuel tank through steering gear drain tap, and the valve element of flux amplification valve is in action of reset spring
Middle position is in down, and system is not turned to；When driver turn steering wheel, two ends of the steering wheel control steering gear to flux amplification valve
Oil-filled, now under the effect of guide oil liquid, Flow amplification valve core movement, valve element is opened, and constant displacement pump is connected with steering cylinder, is
System starts to turn to.When system stops turning to, the pilot pressure oil into Flow amplification valve core one end then passes through Flow amplification
The restriction of valve flows back to fuel tank, and the pressure at valve element two ends is close to balance, amplifies valve core in action of reset spring down-off and is in
Middle position, system stops turning to.In above steering procedure there is restriction loss and spill losses in many places, for example：In the non-work of system
When making, hydraulic oil Jing overflow valves directly flow back to fuel tank, with very big spill losses；When control is turned to, due to being control
The aperture size of the restriction of flux amplification valve is controlling uninterrupted, and restriction loss is larger；When turning to, it is right that driver lacks
The perception of road conditions.
The content of the invention
In order to overcome problem of the above engineering machinery steering in steering, the invention is intended to design one kind can be effective
Reducing energy consumption, makes operator simply light, and system architecture is simple, and driver has the steering of road feel.
Technical scheme provided by the present invention is：A kind of New engineering machinery wire-controlled steering system, primary structure includes：1-
Variable pump steering wheel, 2- variable oil cylinders, 3- ratio triple valves, 4- electromagnetism on-off valves, 5- accumulators, 6-ECU (ECU),
7- angular displacement sensors, 8- steering wheels, 9- force feedback motors, 10- steering cylinders, the hydraulic control one-way valves of 11- first, 12- pressure is passed
Sensor, 13- Fill valves, 14- shuttle valves, the hydraulic control one-way valves of 15- second, the overflow valves of 16- first, 17- solenoid directional control valves, 18- is unidirectional
Valve, the overflow valves of 19- second, 20- filters, 21- fuel tanks.
The New engineering machinery wire-controlled steering system, angular displacement sensor input closure disk, output end connection
ECU, force feedback motor output end closure disk, input connection ECU, steering wheel is rotated, and will be turned by angular displacement sensor
To signal output to ECU；The electric signal input end connection that ECU passes through output end and ratio triple valve, sends to ratio triple valve
Action signal, ratio triple valve control variables oil cylinder, with the change of the change control variables pump swashplate angle that piston rod stretches；
ECU is connected by output end with two control ends of solenoid directional control valve, by ECU control come realize turn to oil circuit commutation and
Break-make；Fill valve is connected on the loop between solenoid directional control valve and steering cylinder, and one end is connected to in-line, other end connection
In oil return line；Shuttle valve is connected on the loop between solenoid directional control valve and steering cylinder, and one end is connected to in-line, and the other end connects
It is connected on oil return line；Connect the first overflow valve and pressure sensor in the oil-out of shuttle valve；Install on the piston rod of steering cylinder
Displacement transducer；Check valve is set on oil circuit between variable pump and solenoid directional control valve；Check valve and solenoid directional control valve it
Between accumulator is set, in the input of accumulator（Go out）End is installed by electromagnetism on-off valve and pressure sensor, the control of electromagnetism on-off valve
End is connected to the delivery outlet of ECU.
Described New engineering machinery wire-controlled steering system, when engineering machinery is not turned to, i.e. steering wheel is not rotated
When, ECU is not received by the turn signal that steering wheel sends, and now ratio triple valve is failure to actuate, and the rodless cavity of variable oil cylinder is straight
The right position operating position for connecing passing ratio triple valve is connected with fuel tank, and piston rod is in rightmost position, and now, the swash plate of variable pump inclines
Angle is maximum, that is, variable pump oil-out is closed, and system is exported without hydraulic oil.
Described New engineering machinery wire-controlled steering system, in the firm fast steering of engineering machinery, angular displacement sensor will
Angular signal passes to ECU, and ECU converts a signal into tach signal, and ECU is by control signal output to ratio triple valve, valve element
Move to right, variable cylinder piston rod moves right, promote the increase of variable pumpage；Turn signal is passed to electromagnetism and is changed by ECU simultaneously
To valve, electromagnetic switch valve events to operating position, by action while variable pump and solenoid directional control valve, engineering machinery is realized
Fast steering.Steering wheel rotating speed is faster, and the displacement that the valve element of ratio triple valve is moved to right is bigger, and piston rod moves to right bigger, variable pump
Discharge capacity is bigger, turns to faster.Turn to while, by displacement transducer gather hydraulic cylinder piston rod stroke, and by its with
Steering wheel output corner relatively come determine whether stop turn to；The piston rod of variable oil cylinder and the valve pocket phase of ratio triple valve
Even, when piston rod reaches certain position, ratio triple valve is closed and is in middle position state, and now piston rod position is fixed, variable
Pump is in quantitative fuel feeding.
Described New engineering machinery wire-controlled steering system, in the firm slow steeirng of engineering machinery, angular displacement sensor will
Angular signal passes to ECU, and ECU converts a signal into tach signal, and control signal output is arrived ratio triple valve by ECU, at a slow speed
When, the electric signal that ECU issues ratio triple valve is less, and now proportion electro-magnet is exerted oneself less, and original valve element dynamic balance is broken,
Move to left under action of reset spring, now, variable cylinder piston rod is moved to the left, promote variable pumpage to reduce；ECU will be turned to
Signal transmission is to solenoid directional control valve, electromagnetic switch valve events to operating position, by moving while variable pump and solenoid directional control valve
Make, realize the slow steeirng of engineering machinery.Steering wheel rotating speed is slower, and the displacement that the valve element of ratio triple valve is moved to left is bigger, passes through
The fluid of variable oil cylinder is fewer, and variable pumpage is less, turns to slower.The piston rod of variable oil cylinder and the valve pocket of ratio triple valve
It is connected, when piston rod reaches certain position, ratio triple valve is closed and is in middle position state, and now piston rod position is fixed, and is become
Amount pump is in quantitative fuel feeding.While turning to, the stroke of hydraulic cylinder is gathered by displacement transducer, and it is gone out with steering wheel
Corner relatively determine whether stop turn to；The piston rod of variable oil cylinder and the valve pocket of ratio triple valve are connected, when piston rod is arrived
During up to certain position, ratio triple valve is closed and is in middle position state, and now piston rod position is fixed, and variable pump is in quantitative confession
Oil.
Described New engineering machinery steering, during engineering machinery is turned to, by hydraulic cylinder displacement transducer
The data of collection and the data of angular displacement sensor collection carry out real time contrast at ECU, to determine that the steering angle of tire is
It is no corresponding with steering wheel angle, instruction is sent by ECU if not corresponding to and is corrected.
Described New engineering machinery steering, when engineering machinery is turned to, when such as there is steering power deficiency, by
ECU to accumulator sends instruction, and electromagnetism on-off valve is opened, and accumulator to steering is oil-filled；When energy storage pressure is relatively low,
ECU controls electromagnetism on-off valve, and system to accumulator is oil-filled.
Described New engineering machinery steering, engineering machinery turn to during, if occur road surface it is bad or
When person turns to motionless, the pressure sensor detection pressure at shuttle valve, if detection pressure is higher than variable pump maximum output pressure, now
System can not be turned to, and now ECU sends instruction to ratio triple valve, make ratio triple valve work in rightmost position, this variations per hour
Pump oil drain out is closed, system unloaded, until system pressure recovers normal, then sends instruction normal work by ECU.
The beneficial effects of the present invention is, electronic technology and hydraulic technique are made full use of in engineering machinery steering,
Mechanically and hydraulically connection more complicated in original steering is eliminated using electronic technology, driver has good road feel,
The change displacement control feature of variable pump is made full use of, the ratio match of variable pumpage and rotating speed is realized, by comparing steering wheel
Corner determines the accuracy of steering angle with the stroke of steering cylinder piston rod, makes full use of the variable pump volumetric void fraction energy
The characteristics of utilization ratio is high, the original throttling of change and overflow are controlled to volumetric void fraction, and energy saving was improved more originally.
Description of the drawings
With reference to the accompanying drawings and examples the present invention will be further described.
Fig. 1 is current engineering machinery steering；
Fig. 2 is the structure chart of New engineering machinery wire-controlled steering system embodiment 1；
Fig. 3 is the structure chart of New engineering machinery wire-controlled steering system embodiment 2；
Fig. 4 is the structure chart of New engineering machinery wire-controlled steering system embodiment 3；
Fig. 5 is the structure chart of New engineering machinery wire-controlled steering system embodiment 4.
Specific embodiment
Embodiment one：
Referring to Fig. 2, a kind of new wire-controlled steering system mainly includes 1- variable pump steering wheels, 2- variable oil cylinders, 3- ratios
Triple valve, 4- electromagnetism on-off valves, 5- accumulators, 6-ECU (ECU), 7- angular displacement sensors, 8- steering wheels, 9- power is anti-
Generating aid, 10- steering cylinders, the hydraulic control one-way valves of 11- first, 12- pressure sensors, 13- Fill valves, 14- shuttle valves, 15- second
Hydraulic control one-way valve, the overflow valves of 16- first, 17- solenoid directional control valves, 18- check valves, the overflow valves of 19- second, 20- filters, 21-
Fuel tank.New engineering machinery wire-controlled steering system steering wheel connects ECU by angular displacement sensor；ECU passes through force feedback motor
It is connected with steering wheel；The electric signal input end of variable control valve is connected with the output end of ECU, the input of ratio triple valve hydraulic oil
End is connected with external guide's oil circuit, and ratio triple valve hydraulic oil output end is connected with variable oil cylinder；The swashplate angle control of variable pump
Mechanism processed is connected with variable cylinder piston rod, and variable pump oil-out is connected with solenoid directional control valve；Solenoid directional control valve and steering cylinder
Oil-feed be connected with oil return opening；New engineering machinery wire-controlled steering system arranges the first hydraulic control one-way valve and the second fluid-control one-way
Valve, is connected on respectively on major loop；New engineering machinery wire-controlled steering system arranges shuttle valve and is connected to New engineering machinery line traffic control
On the major loop of steering, while tapping into oil circuit, another side takes back oil circuit；Shuttle valve oil-out connects the first overflow valve and pressure is passed
Sensor.
Embodiment two：
Be to have changed solenoid directional control valve into electro-hydraulic reversing valve with the difference of embodiment one referring to Fig. 3, electro-hydraulic reversing valve by
One solenoid directional control valve control, its control oil sources is provided by external stable oil sources.
Embodiment three：
Referring to Fig. 4, with the control fluid that the difference of embodiment one is ratio triple valve, provided by accumulator, accumulator
The fluid of offer is through pressure-reducing valve to ratio triple valve fuel feeding.
Example IV：
Referring to Fig. 5, it is that accumulator is simultaneously to ratio triple valve and electro-hydraulic reversing valve with the difference of embodiment two and example three
Control oil is provided, the fluid flowed into from accumulator controls moving left and right for Valve Core for Proportional Direction Valve through pressure-reducing valve；From accumulator
The fluid of inflow connects the oil-in of solenoid directional control valve through pressure-reducing valve, and the left and right of solenoid directional control valve control electro-hydraulic reversing valve valve element is moved
It is dynamic.
Claims (7)
1. a kind of engineering machinery wire-controlled steering system, mainly including steering wheel（8）, angular displacement sensor（7）, force feedback motor
（9）, ECU (ECU)（6）, accumulator（5）, electromagnetism on-off valve（4）, ratio triple valve（3）, variable oil cylinder（2）, variable pump
（1）, solenoid directional control valve（17）, check valve（18）, shuttle valve（14）, the first hydraulic control one-way valve（11）With the second hydraulic control one-way valve
（15）, steering cylinder（10）, the first overflow valve（16）, the second overflow valve（19）, displacement transducer L and pressure sensor P, it is special
Levy and be：The engineering machinery wire-controlled steering system steering wheel connects ECU by angular displacement sensor；The engineering machinery line traffic control
Steering ECU is connected by force feedback motor with steering wheel；The ratio triple valve of the engineering machinery wire-controlled steering system
Electric signal input end is connected with the electrical signal of ECU, and the input of the hydraulic oil of ratio triple valve is connected with guide's oil circuit,
Ratio triple valve hydraulic oil output end is connected with variable oil cylinder；The swashplate angle of the engineering machinery wire-controlled steering system variable pump
Controlling organization is connected with variable cylinder piston rod, and variable pump oil-out is connected with solenoid directional control valve；The engineering machinery line traffic control turns
The oil-in and oil-out of solenoid directional control valve and steering cylinder to system is connected；The engineering machinery wire-controlled steering system is arranged
First hydraulic control one-way valve and the second hydraulic control one-way valve, are connected on respectively on major loop；The engineering machinery wire-controlled steering system sets
Put shuttle valve to be connected on the major loop of engineering machinery wire-controlled steering system, while tapping into oil circuit, another side takes back oil circuit；The work
Journey machinery wire-controlled steering system shuttle valve oil-out connects the first overflow valve and pressure sensor.
2. the engineering machinery wire-controlled steering system according to claims 1, it is characterised in that：The variable pump is that vane type becomes
Amount pump or plunger variable pump.
3. the engineering machinery wire-controlled steering system according to claims 1, it is characterised in that：Variable pump is accompanied with itself pressure
Compensation device.
4. the engineering machinery wire-controlled steering system according to claims 1, it is characterised in that：Electromagnetism is substituted with electro-hydraulic reversing valve
Reversal valve, used as the element of control steering cylinder go to action, its oil circuit control is by external stable Oil-source control.
5. the engineering machinery wire-controlled steering system according to claims 1 or 4, it is characterised in that：In solenoid directional control valve or electricity
Accumulator is set between check valve at the oil-out of liquid reversal valve and variable pump, to steering repairing.
6. the engineering machinery wire-controlled steering system according to claims 5, it is characterised in that：By accumulator directly as ratio
The stable pilot control of triple valve, accumulator is by pressure-reducing valve to ratio triple valve fuel feeding.
7. the engineering machinery wire-controlled steering system according to claims 4, it is characterised in that：The oil circuit control is by accumulator
Control oil sources is provided by pressure-reducing valve to electro-hydraulic reversing valve.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201410230604.5A CN104554432B (en) | 2014-05-29 | 2014-05-29 | Engineering machine steer-by-wire system |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201410230604.5A CN104554432B (en) | 2014-05-29 | 2014-05-29 | Engineering machine steer-by-wire system |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN104554432A CN104554432A (en) | 2015-04-29 |
| CN104554432B true CN104554432B (en) | 2017-04-12 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201410230604.5A Expired - Fee Related CN104554432B (en) | 2014-05-29 | 2014-05-29 | Engineering machine steer-by-wire system |
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| CN (1) | CN104554432B (en) |
Families Citing this family (16)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US9869311B2 (en) * | 2015-05-19 | 2018-01-16 | Caterpillar Inc. | System for estimating a displacement of a pump |
| CN104925129B (en) * | 2015-07-16 | 2017-11-10 | 潍柴动力股份有限公司 | Hydraulic steering system |
| CN105298971B (en) * | 2015-11-13 | 2018-04-13 | 上海华测导航技术股份有限公司 | The hydraulic control valve group of agricultural machinery automatic steering system |
| CN105539574B (en) * | 2015-12-07 | 2017-09-26 | 中国北方车辆研究所 | Automobile back wheel turns to electronically controlled hydraulic system and its control method |
| JP6815267B2 (en) * | 2017-04-18 | 2021-01-20 | 川崎重工業株式会社 | Hydraulic system |
| CN107010106B (en) * | 2017-04-19 | 2018-08-28 | 吉林大学 | A kind of double steering power cylinder hydraulic pressure wire-controlled steering system and method with road feel simulation |
| CN106995005B (en) * | 2017-05-02 | 2018-02-13 | 吉林大学 | A kind of line traffic control hydraulic braking steering |
| CN108100033A (en) * | 2018-01-10 | 2018-06-01 | 西安合众思壮导航技术有限公司 | Turn to fluid distributor |
| CN108791481B (en) * | 2018-05-29 | 2023-11-28 | 浙江万达汽车方向机有限公司 | Hydraulic steering road feel simulator assembly, simulation device and method |
| CN109398477A (en) * | 2018-09-26 | 2019-03-01 | 江苏理工学院 | A kind of engineering mechanical device direction of travel control method and device |
| CN111086558B (en) * | 2019-12-26 | 2022-02-25 | 河北雷萨重型工程机械有限责任公司 | Hydraulic power-assisted steering system, control method and engineering vehicle |
| CN111559424B (en) * | 2020-05-15 | 2022-05-27 | 山推工程机械股份有限公司 | Digital line control steering system and control method and device thereof |
| CN112590922B (en) * | 2020-12-09 | 2023-02-03 | 中冶宝钢技术服务有限公司 | Steering control device and control method for vehicle and vehicle |
| CN112797041A (en) * | 2021-01-28 | 2021-05-14 | 福建龙马环卫装备股份有限公司 | Hydraulic motor bidirectional pressure control system and method thereof |
| CN113062399B (en) * | 2021-04-14 | 2023-08-08 | 徐州徐工矿业机械有限公司 | Excavator rotary motor, brake control release circuit and method thereof and excavator |
| CN113404730B (en) * | 2021-07-30 | 2023-05-05 | 华侨大学 | Steering system of electric loader based on hydraulic accumulator and variable motor |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6321535B2 (en) * | 1997-11-21 | 2001-11-27 | Komatsu Ltd. | Hydraulic circuit for working vehicle |
| JP4247986B2 (en) * | 2003-12-10 | 2009-04-02 | 株式会社小松製作所 | Vehicle steering control device |
| CN202429243U (en) * | 2012-01-16 | 2012-09-12 | 中联重科股份有限公司 | Servo steering controlling system and crane |
| US9347200B2 (en) * | 2012-06-04 | 2016-05-24 | Cnh Industrial America Llc | Fluid control system for work vehicle |
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2014
- 2014-05-29 CN CN201410230604.5A patent/CN104554432B/en not_active Expired - Fee Related
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| CN104554432A (en) | 2015-04-29 |
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