CN111267951A - Electro-hydraulic coupling type all-wheel steering system - Google Patents
Electro-hydraulic coupling type all-wheel steering system Download PDFInfo
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- CN111267951A CN111267951A CN202010180819.6A CN202010180819A CN111267951A CN 111267951 A CN111267951 A CN 111267951A CN 202010180819 A CN202010180819 A CN 202010180819A CN 111267951 A CN111267951 A CN 111267951A
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- steering
- rear axle
- hydraulic cylinder
- centering
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- 230000008878 coupling Effects 0.000 title abstract description 12
- 238000010168 coupling process Methods 0.000 title abstract description 12
- 238000005859 coupling reaction Methods 0.000 title abstract description 12
- 239000007788 liquid Substances 0.000 claims abstract description 39
- 230000001502 supplementing effect Effects 0.000 claims abstract description 37
- 239000012530 fluid Substances 0.000 claims abstract description 32
- 238000001802 infusion Methods 0.000 claims abstract description 28
- 238000004891 communication Methods 0.000 claims description 8
- 230000000149 penetrating effect Effects 0.000 claims description 7
- 238000002637 fluid replacement therapy Methods 0.000 claims description 6
- 238000004080 punching Methods 0.000 claims description 3
- 238000007599 discharging Methods 0.000 claims description 2
- 230000005540 biological transmission Effects 0.000 abstract description 17
- 230000002706 hydrostatic effect Effects 0.000 abstract description 4
- 238000010586 diagram Methods 0.000 description 4
- 238000000034 method Methods 0.000 description 4
- 238000006243 chemical reaction Methods 0.000 description 3
- 230000007246 mechanism Effects 0.000 description 3
- 230000008569 process Effects 0.000 description 3
- 238000011088 calibration curve Methods 0.000 description 2
- 230000008859 change Effects 0.000 description 2
- 230000002159 abnormal effect Effects 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 238000006073 displacement reaction Methods 0.000 description 1
- 238000012423 maintenance Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012544 monitoring process Methods 0.000 description 1
- 230000004044 response Effects 0.000 description 1
- 239000000725 suspension Substances 0.000 description 1
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Classifications
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- 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
- B62D5/065—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 specially adapted means for varying pressurised fluid supply based on need, e.g. on-demand, variable assist
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- 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
- B62D5/04—Power-assisted or power-driven steering electrical, e.g. using an electric servo-motor connected to, or forming part of, the steering gear
- B62D5/0457—Power-assisted or power-driven steering electrical, e.g. using an electric servo-motor connected to, or forming part of, the steering gear characterised by control features of the drive means as such
- B62D5/0481—Power-assisted or power-driven steering electrical, e.g. using an electric servo-motor connected to, or forming part of, the steering gear characterised by control features of the drive means as such monitoring the steering system, e.g. failures
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- 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
- B62D5/04—Power-assisted or power-driven steering electrical, e.g. using an electric servo-motor connected to, or forming part of, the steering gear
- B62D5/0457—Power-assisted or power-driven steering electrical, e.g. using an electric servo-motor connected to, or forming part of, the steering gear characterised by control features of the drive means as such
- B62D5/0481—Power-assisted or power-driven steering electrical, e.g. using an electric servo-motor connected to, or forming part of, the steering gear characterised by control features of the drive means as such monitoring the steering system, e.g. failures
- B62D5/0487—Power-assisted or power-driven steering electrical, e.g. using an electric servo-motor connected to, or forming part of, the steering gear characterised by control features of the drive means as such monitoring the steering system, e.g. failures detecting motor faults
-
- 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
- B62D5/04—Power-assisted or power-driven steering electrical, e.g. using an electric servo-motor connected to, or forming part of, the steering gear
- B62D5/0457—Power-assisted or power-driven steering electrical, e.g. using an electric servo-motor connected to, or forming part of, the steering gear characterised by control features of the drive means as such
- B62D5/0481—Power-assisted or power-driven steering electrical, e.g. using an electric servo-motor connected to, or forming part of, the steering gear characterised by control features of the drive means as such monitoring the steering system, e.g. failures
- B62D5/049—Power-assisted or power-driven steering electrical, e.g. using an electric servo-motor connected to, or forming part of, the steering gear characterised by control features of the drive means as such monitoring the steering system, e.g. failures detecting sensor failures
-
- 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
- B62D5/10—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 type of power unit
- B62D5/12—Piston and cylinder
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- 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
- B62D5/30—Safety devices, e.g. alternate emergency power supply or transmission means to ensure steering upon failure of the primary steering means
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
- B62D—MOTOR VEHICLES; TRAILERS
- B62D6/00—Arrangements for automatically controlling steering depending on driving conditions sensed and responded to, e.g. control circuits
- B62D6/001—Arrangements for automatically controlling steering depending on driving conditions sensed and responded to, e.g. control circuits the torque NOT being among the input parameters
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- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Transportation (AREA)
- Mechanical Engineering (AREA)
- Steering-Linkage Mechanisms And Four-Wheel Steering (AREA)
- Steering Control In Accordance With Driving Conditions (AREA)
- Power Steering Mechanism (AREA)
Abstract
The invention discloses an electro-hydraulic coupling type all-wheel steering system, which comprises: a front axle steering system; a slave cylinder including a first chamber and a second chamber; a rear axle power steering cylinder including a third chamber and a fourth chamber; the first fluid infusion system is communicated with the rear axle power-assisted steering hydraulic cylinder and is used for infusing fluid to the third chamber; the second liquid supplementing system is communicated with the rear axle power-assisted steering hydraulic cylinder and is used for supplementing liquid to the fourth cavity; a steering mode valve disposed between the slave cylinder and the rear axle power steering cylinder for selectively communicating the first and second chambers, the first and third chambers and the second and fourth chambers, or the first and fourth chambers and the second and third chambers. The coupling drive of motor drive and hydrostatic transmission is adopted, and various steering modes and rear wheel aligning functions of all-wheel steering are realized.
Description
Technical Field
The invention relates to the technical field of vehicle steering, in particular to an electro-hydraulic coupling type all-wheel steering system.
Background
At present, an all-wheel steering system of a vehicle mainly comprises a pure mechanical all-wheel steering system, an electric control hydraulic all-wheel steering system and an electric all-wheel steering system. The steering rocker arms and the connecting rods thereof of the front axle and the rear axle in the pure mechanical all-wheel steering system occupy large space and are difficult to arrange due to space limitation. After the steering system is used for a long time, a steering rocker arm pull rod can generate fatigue wear, and further the error of the rotation angle of front and rear wheels is increased. The electric control hydraulic type all-wheel steering system realizes the rotation of front and rear wheels through the electric control hydraulic proportional relation, but the whole set of hydraulic system is too complex. The electric all-wheel steering system finishes a front-rear wheel steering angle relation curve through calibration of the control system, so that steering in multiple modes is realized, but the front-rear wheel steering angle relation curve of the control system is difficult to calibrate accurately, and the whole system depends on a steering angle sensor too much; because the rear steering system is completely independent, a driver cannot control the rotation angle of the wheels of the rear axle through the steering wheel in the all-wheel steering process.
The front axle of the existing all-wheel steering system transmits the torque and the corner information of a steering wheel to a front axle steering gear through a pull rod so as to complete the steering of the front wheels; at the moment, the rear axle wheels are locked through a mechanical mechanism; i.e. the front wheel steering command is completed. When the rear axle is required to steer, the mechanical structure is pushed to unlock through pneumatic or hydraulic driving, and then a steering driving system of the rear axle pushes a steering knuckle arm of the rear axle to steer. The operation process is complicated.
Disclosure of Invention
The invention aims to design and develop an electro-hydraulic coupling type all-wheel steering system, which adopts coupling drive of motor drive and hydrostatic transmission to realize multiple steering modes and a rear wheel aligning function of all-wheel steering.
The technical scheme provided by the invention is as follows:
an electro-hydraulic coupled all-wheel steering system comprising:
a front axle steering system;
the driven hydraulic cylinder is internally provided with a first piston, is divided into a first chamber and a second chamber, is coaxially provided with a first piston rod in a penetrating manner with the first piston, and is connected with the front wheel steering system;
the rear axle power-assisted steering hydraulic cylinder is internally provided with a second piston, is divided into a third cavity and a fourth cavity, and is coaxially provided with a second piston rod in a penetrating manner with the second piston, and the second piston rod is connected with a rear axle of the vehicle and is used for driving the rear axle of the vehicle to steer;
the first fluid infusion system is communicated with the rear axle power-assisted steering hydraulic cylinder and is used for infusing fluid to the third chamber;
the second liquid supplementing system is communicated with the rear axle power-assisted steering hydraulic cylinder and is used for supplementing liquid to the fourth cavity;
a steering mode valve disposed between the slave cylinder and the rear axle power steering cylinder for selectively communicating the first and second chambers, the first and third chambers and the second and fourth chambers, or the first and fourth chambers and the second and third chambers;
a short circuit valve, which is arranged between the driven hydraulic cylinder and the rear axle power-assisted steering hydraulic cylinder and is used for short-circuiting the rear axle power-assisted steering hydraulic cylinder;
the steering oil pump assembly is communicated with the first liquid supplementing system and the second liquid supplementing system and is used for supplying oil to the first liquid supplementing system and the second liquid supplementing system;
the rear axle centering module is communicated with the steering oil pump assembly, is connected with a rear axle of the vehicle and is used for centering the rear axle;
wherein,
when the system is in a front wheel steering mode, the first chamber is communicated with the second chamber, the short-circuit valve is powered off, the rear axle power-assisted steering hydraulic cylinder does not work, and the rear axle centering module works;
when the system is in an all-wheel same-phase steering mode, the first chamber is communicated with the third chamber, the second chamber is communicated with the fourth chamber, the short-circuit valve is powered off, the rear axle power-assisted steering hydraulic cylinder works, and the rear axle centering module does not work;
when the system is in an all-wheel reverse phase steering mode, the first chamber is communicated with the fourth chamber, the second chamber is communicated with the third chamber, the short-circuit valve is powered off, the rear axle power-assisted steering hydraulic cylinder works, and the rear axle centering module does not work;
when the system is in a rear wheel independent centering mode, the short-circuit valve is electrified, and the rear axle centering module works.
Preferably, the first fluid replacement wash system includes:
one end of the first one-way valve is communicated with the rear axle power-assisted steering hydraulic cylinder, and the other end of the first one-way valve is communicated with the steering oil pump assembly;
one end of the first overflow valve is communicated with the rear axle power-assisted steering hydraulic cylinder, and the other end of the first overflow valve is communicated with the steering oil pump assembly;
wherein the first check valve is connected in parallel with the first overflow valve.
Preferably, the second fluid infusion system includes:
one end of the second one-way valve is communicated with the rear axle power-assisted steering hydraulic cylinder, and the other end of the second one-way valve is communicated with the steering oil pump assembly;
one end of the second overflow valve is communicated with the rear axle power-assisted steering hydraulic cylinder, and the other end of the second overflow valve is communicated with the steering oil pump assembly;
wherein the second check valve is connected in parallel with the second overflow valve.
Preferably, the method further comprises the following steps:
the fluid infusion energy accumulator is communicated with the first fluid infusion system and the second fluid infusion system;
a pressure switch in communication with the fluid replacement accumulator;
and the pressure sensor is communicated with the pressure switch and is used for detecting the outlet pressure of the fluid infusion energy accumulator.
Preferably, the steering oil pump assembly includes:
the steering oil pump is respectively communicated with the first liquid supplementing system, the second liquid supplementing system, the centering module and the oil tank through a steering oil pump working mode switching valve;
a steering oil pump overflow valve connected in parallel with the steering oil pump;
when the steering oil pump working mode switching valve is arranged at one end, the steering oil pump punches the fluid infusion energy accumulator; when the steering oil pump working mode switching valve is arranged at the other end, the steering oil pump punches the rear axle centering module; when the steering oil pump working mode switching valve is positioned in the middle, the steering oil pump is in a self-pressure-discharging state.
Preferably, the centering module includes:
a centering check valve communicating with the steering oil pump operation mode switching valve;
a centering accumulator in communication with the centering check valve;
the centering hydraulic cylinder is a three-cavity hydraulic cylinder, is communicated with the centering energy accumulator and is used for aligning the rear axle of the vehicle;
the centering pressure sensor is connected with the centering hydraulic cylinder and used for detecting the pressure of cavities at two ends of the centering hydraulic cylinder;
and the centering reversing valve is arranged between the centering energy accumulator and the centering hydraulic cylinder and is used for switching the punching and pressure relief states of the centering hydraulic cylinder.
Preferably, the front axle steering system includes:
a steering wheel;
one end of the steering column is fixedly connected with the center of the steering wheel, and the other end of the steering column is connected with a steering middle shaft through a driving motor assembly;
a front wheel steering gear connected to the steering intermediate shaft;
the front wheel steering device comprises:
one end of the first spherical hinge pull rod assembly is connected with a front wheel on one side of the vehicle;
the gear rack steering gear is connected with the other end of the first spherical hinge pull rod assembly;
one end of the second spherical hinge pull rod assembly is connected with the front wheel on the other side of the vehicle, and the other end of the second spherical hinge pull rod assembly is connected with the rack-and-pinion steering gear through the driven hydraulic cylinder;
and two ends of the first piston rod are respectively connected with the rack and pinion steering gear and the second spherical hinge pull rod assembly.
Preferably, the second piston rod is respectively connected with the steering main pin knuckle arms at two ends of the rear axle of the vehicle through a rear axle ball joint hinged pull rod.
Preferably, one end of the centering hydraulic cylinder is mounted on the support at the bottom end of the middle part of the axle in a spherical hinge mode, and the other end of the centering hydraulic cylinder is mounted on a knuckle arm extending out of the lower end of the steering main pin of the rear axle in a spherical hinge mode.
Preferably, the controller is further comprised, and comprises a power supply system, a sensor system, a communication system, a solenoid valve driving system, a motor system and a control system.
(1) The electro-hydraulic coupling type all-wheel steering system provided by the invention adopts motor drive and hydrostatic transmission drive, and realizes multiple steering modes and a rear wheel aligning function of all-wheel steering.
(2) The front axle steering system of the system can be changed according to an electric gear rack steering gear on the market, and has small change and high feasibility.
(3) The rear axle steering system of the all-wheel steering system is simple in structure and easy to arrange.
(4) Under the condition that a vehicle sensor system fails or the requirement on the vehicle anti-interference performance is high, the rear axle can be centered through the rear axle centering system.
Drawings
Fig. 1 is a schematic structural diagram of the electro-hydraulic coupling type all-wheel steering system.
Fig. 2 is a hydraulic circuit diagram of the steering system of the present invention.
Fig. 3 is a schematic structural diagram of a front wheel steering system according to the present invention.
Fig. 4 is a schematic structural diagram of the rear wheel steering system according to the present invention.
Detailed Description
The present invention is further described in detail below with reference to the attached drawings so that those skilled in the art can implement the invention by referring to the description text.
As shown in fig. 1 and 3, the invention provides an electro-hydraulic coupling type all-wheel steering system, which comprises a front axle steering system, a rear axle steering system, a hydraulic transmission system and a steering control system thereof. The whole system can realize multiple steering modes such as front wheel steering, all-wheel same-phase steering, all-wheel reverse-phase steering, independent centering and locking of rear wheels and the like through the working state of the sensor steering actuator and the running state of the whole vehicle.
The front wheel steering system comprises a steering wheel 24 and a steering column 25, wherein one end of the steering column 25 is in splined connection with the center of the steering wheel 24, a driving motor assembly 26 is connected with the other end of the steering column 25 in a splined connection mode, a steering intermediate shaft 27 is in splined connection with the driving motor assembly 26, and a front wheel steering gear 28 is connected with the steering intermediate shaft 27; the steering column 25, the driving motor assembly 26 and the steering intermediate shaft 27 complete the transmission of steering wheel angle and torque to the front wheel steering gear. The front wheel steering device 28 comprises a first front axle ball joint pull rod assembly 1, and one end of the first front axle ball joint pull rod assembly is connected with a front wheel on one side of the vehicle. And a gear rack steering gear 2 is connected with the first front axle spherical hinge pull rod assembly 1, a second front axle spherical hinge pull rod assembly 4 is connected with the gear rack steering gear 2 through a slave hydraulic cylinder 3, and the second front axle spherical hinge pull rod assembly 4 is connected with the front wheel on the other side of the vehicle, so that the front axle steering of the vehicle is realized. A driven hydraulic cylinder 3 is arranged between the rack and pinion steering gear 2 and the second spherical hinge pull rod assembly 4, a first piston is arranged in the driven hydraulic cylinder 3, the driven hydraulic cylinder 3 is divided into a first cavity and a second cavity, a first piston rod is coaxially arranged with the first piston in a penetrating mode and is arranged in a partially symmetrical mode at two ends of the first piston, and two ends of the first piston rod are respectively connected with the rack and pinion steering gear 2 and the second spherical hinge pull rod assembly 4.
The all-wheel steering system drives the front wheels to steer through the steering wheel input torque of a driver and the output torque of the driving motor assembly in a front wheel steering mode; in addition, the driving motor assembly 26 drives the front wheel to steer and simultaneously drives the driven hydraulic cylinder 3 to axially move to extrude oil to drive the rear wheel to steer, and in the aspect of selection of the driven hydraulic cylinder, the steering load of the motor is reduced by selecting a cylinder with a smaller working area on the basis of ensuring the working flow of the rear axle hydraulic cylinder.
As shown in fig. 2, the hydraulic transmission system includes four modules, which are a steering mode switching module, a rear axle transmission fluid infusion module, a steering oil pump working mode switching module, and a rear axle centering module.
The steering mode switching module comprises a driven hydraulic cylinder 3, a steering mode control valve 5, a rear axle steering short-circuit valve 6 and a rear axle steering power-assisted hydraulic cylinder 7. The driven hydraulic cylinder 3 is internally provided with a first piston, the driven hydraulic cylinder 3 is divided into a first cavity and a second cavity, a first piston rod is coaxially arranged with the first piston in a penetrating mode and is arranged at the two ends of the first piston in a partially symmetrical mode, and the two ends of the first piston rod are connected with the front wheel steering system. The power-assisted steering hydraulic cylinder 7 is internally provided with a second piston, the rear axle power-assisted steering hydraulic cylinder 7 is divided into a third cavity and a fourth cavity, a second piston rod is coaxially arranged with the second piston in a penetrating mode, and the second piston rod is connected with a rear axle of the vehicle and used for driving the rear axle of the vehicle to steer. A steering mode valve 5 is provided between the slave cylinder 5 and the rear axle power steering cylinder 7 for selectively communicating the first and second chambers, the first and third chambers and the second and fourth chambers, or the first and fourth chambers and the second and third chambers. And the rear axle steering short-circuit valve 6 is arranged between the driven hydraulic cylinder 3 and the rear axle power-assisted steering hydraulic cylinder 7 and is used for short-circuiting the power-assisted steering hydraulic cylinder 7, so that the power-assisted steering hydraulic cylinder 7 does not work.
The steering mode switching module is a closed working environment, namely the driving oil of the rear axle steering power-assisted hydraulic cylinder 7 only comes from the driven hydraulic cylinder 3. As shown in fig. 2, the steering mode control valve 5 is a three-position four-way valve in which the position function is M-type; the left position corresponds to the same phase steering mode of the whole wheel, and the right position corresponds to the reverse phase steering mode of the whole wheel. The rear axle steering short-circuit valve 6 is a two-position two-way electromagnetic valve, and when the electromagnetic valve is electrified, the pressure difference between two cavities of the rear axle steering power-assisted hydraulic cylinder 7 is zero.
The rear axle transmission fluid infusion module comprises a first fluid infusion system, which is communicated with the rear axle power-assisted steering hydraulic cylinder 7 and used for infusing fluid to a third chamber; and the second liquid supplementing system is communicated with the rear axle power-assisted steering hydraulic cylinder 7 and is used for supplementing liquid to the fourth cavity. The first liquid supplementing system comprises a first liquid supplementing one-way valve 8, one end of the first liquid supplementing one-way valve is communicated with the rear axle power-assisted steering hydraulic cylinder 7, and the other end of the first liquid supplementing one-way valve is communicated with a steering oil pump assembly (a steering oil pump working mode conversion module); one end of the first liquid supplementing overflow valve is communicated with the rear axle power-assisted steering hydraulic cylinder 7, and the other end of the first liquid supplementing overflow valve is communicated with the steering oil pump assembly; and the first liquid supplementing one-way valve is connected with the first liquid supplementing overflow valve in parallel. The second liquid supplementing system comprises a second liquid supplementing one-way valve 10, one end of the second liquid supplementing one-way valve is communicated with the rear axle power-assisted steering hydraulic cylinder 7, and the other end of the second liquid supplementing one-way valve is communicated with a steering oil pump assembly (a steering oil pump working mode conversion module); one end of the second liquid supplementing overflow valve 11 is communicated with the rear axle power-assisted steering hydraulic cylinder 7, and the other end of the second liquid supplementing overflow valve is communicated with the steering oil pump assembly; and the second liquid supplementing one-way valve is connected with the second liquid supplementing overflow valve in parallel. And a fluid infusion energy accumulator 12, a pressure switch 13 and a fluid infusion pipeline pressure sensor 14 are sequentially communicated with the first fluid infusion system and the second fluid infusion system. The pressure switch 13 is used as an electric control switch for stamping the steering oil pump 17 to the fluid infusion energy accumulator 12, and the control object of the pressure switch is the left coil of the steering oil pump working mode reversing valve 15; and the fluid infusion pipeline pressure sensor 14 is used for detecting the outlet pressure of the energy accumulator and preventing the working mode reversing valve of the steering oil pump and the rear axle transmission fluid infusion module from being out of order. The module is used for supplementing liquid to a transmission oil way of the rear axle steering power-assisted hydraulic cylinder 7 so as to ensure the accuracy of transmission. In addition, in order to prevent a large back pressure on the rear wheel steering hydraulic line, the working pressure of the hydraulic accumulator 12 should be as small as possible on the basis of preventing the steering oil pump working mode switching valve 15 from being frequently turned on and off.
The steering oil pump working mode conversion module (steering oil pump assembly) comprises an oil tank 16, a steering oil pump 17, a steering oil pump overflow valve 18 and a steering oil pump working mode switching valve 15; a steering oil pump 17, one end of which is communicated with the fluid infusion line pressure sensor 14; an oil tank is communicated with the other end of the steering oil pump 17. A steering oil pump relief valve 18 is connected in parallel with the steering oil pump 17. A steering oil pump operation mode switching valve 15 for switching the operation mode of the steering oil pump 17 is provided between the steering oil pump 17 and the fluid replacement line pressure sensor 14. The steering oil pump working mode switching valve 15 is a three-position four-way reversing valve, and the middle position function is M-shaped. The three positions from left to right respectively correspond to the working states of three steering oil pumps, including the self-pressure relief working state of the steering oil pump, the stamping working state of the fluid infusion energy accumulator and the centering working state of the rear axle centering hydraulic cylinder. Namely, when the steering oil pump working mode switching valve 15 is at the left end, the steering oil pump 17 stamps the fluid infusion accumulator 12; when the steering oil pump working mode switching valve 15 is at the right end, the steering oil pump 17 punches towards the rear axle centering module; when the steering oil pump operation mode switching valve 15 is in the middle, the steering oil pump 17 is in a self-pressurizing state.
The rear axle centering module comprises a rear axle centering one-way valve 19, a rear axle centering energy accumulator 20, a rear axle centering reversing valve 21, a rear axle centering pressure sensor 22 and a rear axle centering hydraulic cylinder 23. The rear axle centering one-way valve 19 is communicated with the steering oil pump working mode switching valve 15, a rear axle centering energy accumulator 20 is communicated with the rear axle centering one-way valve 19, and a rear axle centering hydraulic cylinder 23 is communicated with the rear axle centering energy accumulator 20 and used for aligning the rear wheels of the vehicle. A rear axle centering reversing valve 21 is arranged between the rear axle centering energy accumulator 20 and the rear axle centering hydraulic cylinder 23 and is used for changing the direction of oil in the rear axle centering module. A rear axle centering pressure sensor 22 is provided in parallel with the rear axle centering hydraulic cylinder 23. The rear axle centering one-way valve 19 is used for preventing oil liquid of the rear axle centering energy accumulator 20 from flowing backwards. The left and right floating pistons in the rear axle centering hydraulic cylinder 23 are separated on both sides by an annular boss inside the cylinder barrel, when high pressure is introduced into the two cavities at the end part, the two floating pistons drive the piston rods to move together, and finally the piston rods move to the middle position under the limit of the annular boss. The rear axle centering pressure sensor 22 is used for detecting the pressure values of the leftmost oil cavity and the rightmost oil cavity of the rear axle centering hydraulic cylinder so as to ensure that the rear axle has enough moment to ensure that the rear wheel is aligned. In the centered state, the two end chambers of the rear axle centering accumulator 20 and the rear axle centering hydraulic cylinder 23 are isobaric.
As shown in fig. 4, the rear axle steering system mainly comprises a rear axle steering power-assisted hydraulic cylinder 7, a rear axle centering hydraulic cylinder 23, a first rear axle ball joint tie rod 29, a second rear axle ball joint tie rod 30 and a rear axle 31. The rear axle steering power-assisted hydraulic cylinder 7 is a double-acting double-outlet hydraulic cylinder, and two ends of the hydraulic cylinder are connected with ball joint hinged pull rods; the other end of the ball joint connecting rod is connected with a knuckle arm extending out of the lower end of the steering main pin through a ball joint pin. When the vehicle is in a straight-ahead state, the two ball-head hinged pull rods are symmetrically arranged. Namely, the axial movement of the hydraulic cylinder and the rotation of the steering main pin are realized by a set of crank-slider mechanism. The rear axle steering power-assisted hydraulic cylinder 7 is connected with a rear axle 31 through a first rear axle ball joint connecting rod 29 and a second rear axle ball joint connecting rod 30. The two ends of the rear axle centering hydraulic cylinder 23 are both spherical hinges, one end of the rear axle centering hydraulic cylinder is installed at the bottom end of the middle part of the axle, and the other end of the rear axle centering hydraulic cylinder is installed on a knuckle arm extending out of the lower end of the steering main pin of the rear axle 31.
The steering control system (controller) for all-wheel steering comprises a power supply system, a sensor system, a communication system, an electromagnetic valve driving system, a motor system and a control system. The control system is used for carrying out coordination control on the motor system and the solenoid valve system through power supply of the power supply system, feedback of the sensor system and monitoring data transmission of the communication system. On one hand, the motor system controls the steering angle of the front wheel according to the steering angle input of the steering wheel, and matches the response characteristic of the rear wheel steering by adjusting the steering angle and the rotating speed of the motor; on the one hand, the working state of the steering oil pump is adjusted according to the requirements of the hydraulic system. The electromagnetic valve module is used for switching on and off the coil through an instruction of a control system so as to match different steering working conditions; the sensor module is used for acquiring the rotation angles of the front wheel and the rear wheel, the roll angle of the vehicle body and the pressure signal of the hydraulic system.
The sensor module specifically comprises: the steering wheel corner sensor is used for acquiring a steering wheel corner signal; the rear wheel steering angle sensor is used for acquiring a rear wheel steering angle signal; (ii) a The wheel speed sensor is used for estimating the speed of the whole vehicle; the axle height and rotation angle sensor is used for measuring the heights of the vehicle frames on the left side and the right side of the suspension frame so as to estimate a vehicle body inclination angle signal of the whole vehicle; and the pressure sensor is used for acquiring the pressure of the rear axle working cavity, the pressure of the middle cavity, the pressure of the fluid infusion energy accumulator and the pressure of the centering energy accumulator.
The controller also comprises an alarm module of the all-wheel steering system, when the hydraulic system is in fault, the sensor module is abnormal, the motor system is in fault or the turning angle and the vehicle speed of the vehicle do not meet the switching requirement of the steering mode, the alarm module gives an alarm and prompts a driver, and vehicle maintenance personnel can determine specific faults to maintain according to fault codes of control values.
The electromagnetic valve module switches on and off the coil through an instruction of the control system so as to match different steering working conditions, and is specifically shown in table 1.
TABLE 1 working state of electromagnetic valve corresponding to steering condition
(wherein 1 represents that the solenoid valve coil is energized, and 0 represents that the solenoid valve coil is not energized)
When the system is in a front wheel steering mode, the first chamber is communicated with the second chamber, the short-circuit valve is powered off, the rear axle power-assisted steering hydraulic cylinder does not work, and the rear axle centering module works;
when the system is in an all-wheel same-phase steering mode, the first chamber is communicated with the third chamber, the second chamber is communicated with the fourth chamber, the short-circuit valve is powered off, the rear axle power-assisted steering hydraulic cylinder works, and the rear axle centering module does not work;
when the system is in an all-wheel reverse phase steering mode, the first chamber is communicated with the fourth chamber, the second chamber is communicated with the third chamber, the short-circuit valve is powered off, the rear axle power-assisted steering hydraulic cylinder works, and the rear axle centering module does not work;
when the system is in a rear wheel independent centering mode, the short-circuit valve is electrified, and the rear axle centering module works.
The specific process is as follows:
when the system is started, the output signals of the pressure sensor 14 and the pressure sensor 22 are firstly detected, and the two side coils of the electromagnetic valve 15 are controlled to be powered on or powered off according to control logic so as to realize the punching of the energy accumulator 12 and the energy accumulator 20.
The default of the system is in a front wheel steering mode, at the moment, the electromagnetic valves 5, 6 and 21 are all powered off, the first cavity and the second cavity of the driven hydraulic cylinder are communicated, and the driven hydraulic cylinder does not generate loads on the driving motor. When the steering wheel receives a steering wheel turning signal of a driver, the driving motor outputs boosting torque according to a calibration curve and transmits the boosting torque to the gear, and finally the wheels on two sides of the front axle are rotated through gear and rack transmission and connecting rod transmission.
When a driver presses a switch for the same-phase steering of all wheels, the coil on the left side of the electromagnetic valve 5 is powered off, the coil on the right side of the electromagnetic valve 5 is powered on, the coil on the 6 side of the electromagnetic valve is powered off, the coil on the 21 side of the electromagnetic valve is powered on, and all cavities of the centering hydraulic cylinder are communicated with the oil tank. When the steering wheel receives a steering wheel rotation angle signal of a driver, the driving motor outputs an assistance torque according to a calibration curve and transmits the assistance torque to the gear, then the assistance torque is transmitted to the gear through the rack-and-pinion transmission driving connecting rod to complete the rotation of the wheels at two sides of the front axle and drive the driven hydraulic cylinder to extrude oil to the rear axle assistance steering hydraulic cylinder, and when the rear axle assistance hydraulic cylinder completely overcomes the steering resistance torque of the rear axle, the rear axle assistance hydraulic cylinder generates axial displacement and drives the rear wheels to rotate through the slider-crank mechanisms at the two ends of the rear axle assistance hydraulic cylinder.
When a driver presses a switch for all-wheel reverse-phase steering, a left coil of the electromagnetic valve 5 is electrified, a right coil of the electromagnetic valve 5 is powered off, a coil of the electromagnetic valve 6 is powered off, a coil of the electromagnetic valve 21 is electrified, and all cavities of the centering hydraulic cylinder are communicated with the oil tank. When the steering wheel receives a steering signal of the steering wheel of a driver, the front wheel steering system completes front wheel steering according to the principle of all-wheel in-phase steering. At the moment, the electromagnetic valve 5 changes the oil liquid transmission routes of the driven hydraulic cylinder and the rear axle power-assisted hydraulic cylinder, so that the rear axle wheels and the front axle wheels rotate around the corresponding steering main pins in opposite directions.
When a driver presses a switch of the rear axle centering, the electromagnetic valve 5 and the electromagnetic valve 21 are powered off, the electromagnetic valve 6 is powered on, the rear axle power-assisted steering hydraulic cylinder is short-circuited by the electromagnetic valve 6, and high-pressure oil is introduced into cavities at two ends of the rear axle centering hydraulic cylinder, so that a piston rod is squeezed to the middle position by a floating piston in the centering hydraulic cylinder, and the wheel centering of the rear axle is realized.
The electro-hydraulic coupling type all-wheel steering system provided by the invention adopts coupling drive of motor drive and hydrostatic transmission, and realizes multiple steering modes and a rear wheel aligning function of all-wheel steering. The front axle steering system of the system can be changed according to an electric gear rack steering gear on the market, and has small change and high feasibility. And the rear axle steering system of the all-wheel steering system is simple in structure and easy to arrange. Under the condition that a vehicle sensor system fails or the requirement on the vehicle anti-interference performance is high, the rear axle can be centered through the rear axle centering system.
While embodiments of the invention have been described above, it is not limited to the applications set forth in the description and the embodiments, which are fully applicable in various fields of endeavor to which the invention pertains, and further modifications may readily be made by those skilled in the art, it being understood that the invention is not limited to the details shown and described herein without departing from the general concept defined by the appended claims and their equivalents.
Claims (10)
1. An electro-hydraulic coupled all-wheel steering system, comprising:
a front axle steering system;
the driven hydraulic cylinder is internally provided with a first piston, is divided into a first chamber and a second chamber, is coaxially provided with a first piston rod in a penetrating manner with the first piston, and is connected with the front wheel steering system;
the rear axle power-assisted steering hydraulic cylinder is internally provided with a second piston, is divided into a third cavity and a fourth cavity, and is coaxially provided with a second piston rod in a penetrating manner with the second piston, and the second piston rod is connected with a rear axle of the vehicle and is used for driving the rear axle of the vehicle to steer;
the first fluid infusion system is communicated with the rear axle power-assisted steering hydraulic cylinder and is used for infusing fluid to the third chamber;
the second liquid supplementing system is communicated with the rear axle power-assisted steering hydraulic cylinder and is used for supplementing liquid to the fourth cavity;
a steering mode valve disposed between the slave cylinder and the rear axle power steering cylinder for selectively communicating the first and second chambers, the first and third chambers and the second and fourth chambers, or the first and fourth chambers and the second and third chambers;
a short circuit valve, which is arranged between the driven hydraulic cylinder and the rear axle power-assisted steering hydraulic cylinder and is used for short-circuiting the rear axle power-assisted steering hydraulic cylinder;
the steering oil pump assembly is communicated with the first liquid supplementing system and the second liquid supplementing system and is used for supplying oil to the first liquid supplementing system and the second liquid supplementing system;
the rear axle centering module is communicated with the steering oil pump assembly, is connected with a rear axle of the vehicle and is used for centering the rear axle;
wherein,
when the system is in a front wheel steering mode, the first chamber is communicated with the second chamber, the short-circuit valve is powered off, the rear axle power-assisted steering hydraulic cylinder does not work, and the rear axle centering module works;
when the system is in an all-wheel same-phase steering mode, the first chamber is communicated with the third chamber, the second chamber is communicated with the fourth chamber, the short-circuit valve is powered off, the rear axle power-assisted steering hydraulic cylinder works, and the rear axle centering module does not work;
when the system is in an all-wheel reverse phase steering mode, the first chamber is communicated with the fourth chamber, the second chamber is communicated with the third chamber, the short-circuit valve is powered off, the rear axle power-assisted steering hydraulic cylinder works, and the rear axle centering module does not work;
when the system is in a rear wheel independent centering mode, the short-circuit valve is electrified, and the rear axle centering module works.
2. The electro-hydraulic coupled all-wheel steering system of claim 1, wherein the first fluid replacement wash system comprises:
one end of the first one-way valve is communicated with the rear axle power-assisted steering hydraulic cylinder, and the other end of the first one-way valve is communicated with the steering oil pump assembly;
one end of the first overflow valve is communicated with the rear axle power-assisted steering hydraulic cylinder, and the other end of the first overflow valve is communicated with the steering oil pump assembly;
wherein the first check valve is connected in parallel with the first overflow valve.
3. The electro-hydraulic coupled all-wheel steering system of claim 2, wherein the second fluid replacement system comprises:
one end of the second one-way valve is communicated with the rear axle power-assisted steering hydraulic cylinder, and the other end of the second one-way valve is communicated with the steering oil pump assembly;
one end of the second overflow valve is communicated with the rear axle power-assisted steering hydraulic cylinder, and the other end of the second overflow valve is communicated with the steering oil pump assembly;
wherein the second check valve is connected in parallel with the second overflow valve.
4. The electro-hydraulic coupled all wheel steering system of claim 3, further comprising:
the fluid infusion energy accumulator is communicated with the first fluid infusion system and the second fluid infusion system;
a pressure switch in communication with the fluid replacement accumulator;
and the pressure sensor is communicated with the pressure switch and is used for detecting the outlet pressure of the fluid infusion energy accumulator.
5. The electro-hydraulic coupled all-wheel steering system of claim 4, wherein the steering oil pump assembly comprises:
the steering oil pump is respectively communicated with the first liquid supplementing system, the second liquid supplementing system, the centering module and the oil tank through a steering oil pump working mode switching valve;
a steering oil pump overflow valve connected in parallel with the steering oil pump;
when the steering oil pump working mode switching valve is arranged at one end, the steering oil pump punches the fluid infusion energy accumulator; when the steering oil pump working mode switching valve is arranged at the other end, the steering oil pump punches the rear axle centering module; when the steering oil pump working mode switching valve is positioned in the middle, the steering oil pump is in a self-pressure-discharging state.
6. The electro-hydraulic coupled all wheel steering system of claim 5, wherein the centering module comprises:
a centering check valve communicating with the steering oil pump operation mode switching valve;
a centering accumulator in communication with the centering check valve;
the centering hydraulic cylinder is a three-cavity hydraulic cylinder, is communicated with the centering energy accumulator and is used for aligning the rear axle of the vehicle;
the centering pressure sensor is connected with the centering hydraulic cylinder and used for detecting the pressure of cavities at two ends of the centering hydraulic cylinder;
and the centering reversing valve is arranged between the centering energy accumulator and the centering hydraulic cylinder and is used for switching the punching and pressure relief states of the centering hydraulic cylinder.
7. The electro-hydraulic coupled all-wheel steering system according to any one of claims 1 to 6, wherein the front axle steering system comprises:
a steering wheel;
one end of the steering column is fixedly connected with the center of the steering wheel, and the other end of the steering column is connected with a steering middle shaft through a driving motor assembly;
a front wheel steering gear connected to the steering intermediate shaft;
the front wheel steering device comprises:
one end of the first spherical hinge pull rod assembly is connected with a front wheel on one side of the vehicle;
the gear rack steering gear is connected with the other end of the first spherical hinge pull rod assembly;
one end of the second spherical hinge pull rod assembly is connected with the front wheel on the other side of the vehicle, and the other end of the second spherical hinge pull rod assembly is connected with the rack-and-pinion steering gear through the driven hydraulic cylinder;
and two ends of the first piston rod are respectively connected with the rack and pinion steering gear and the second spherical hinge pull rod assembly.
8. The electro-hydraulic coupled all-wheel steering system according to claim 7, wherein the second piston rod is connected to the kingpin arms at both ends of the rear axle of the vehicle through rear axle ball joint tie rods, respectively.
9. The electro-hydraulic coupled all-wheel steering system according to claim 6, wherein one end of the centering hydraulic cylinder is mounted on a bracket at the bottom end of the middle part of the axle, and the other end of the centering hydraulic cylinder is mounted on a knuckle arm extending out of the lower end of the steering main pin of the rear axle.
10. The electro-hydraulic coupled all wheel steering system of claim 8 or 9, further comprising a controller including a power system, a sensor system, a communication system, a solenoid valve drive system, a motor system, and a control system.
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