CN111959604B - Multi-mode steering system - Google Patents
Multi-mode steering system Download PDFInfo
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- CN111959604B CN111959604B CN202010731037.7A CN202010731037A CN111959604B CN 111959604 B CN111959604 B CN 111959604B CN 202010731037 A CN202010731037 A CN 202010731037A CN 111959604 B CN111959604 B CN 111959604B
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- port
- valve
- reversing valve
- wheel steering
- reversing
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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
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- A—HUMAN NECESSITIES
- A01—AGRICULTURE; FORESTRY; ANIMAL HUSBANDRY; HUNTING; TRAPPING; FISHING
- A01B—SOIL WORKING IN AGRICULTURE OR FORESTRY; PARTS, DETAILS, OR ACCESSORIES OF AGRICULTURAL MACHINES OR IMPLEMENTS, IN GENERAL
- A01B69/00—Steering of agricultural machines or implements; Guiding agricultural machines or implements on a desired track
- A01B69/007—Steering or guiding of agricultural vehicles, e.g. steering of the tractor to keep the plough in the furrow
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
- B62D—MOTOR VEHICLES; TRAILERS
- B62D7/00—Steering linkage; Stub axles or their mountings
- B62D7/06—Steering linkage; Stub axles or their mountings for individually-pivoted wheels, e.g. on king-pins
- B62D7/14—Steering linkage; Stub axles or their mountings for individually-pivoted wheels, e.g. on king-pins the pivotal axes being situated in more than one plane transverse to the longitudinal centre line of the vehicle, e.g. all-wheel steering
- B62D7/142—Steering linkage; Stub axles or their mountings for individually-pivoted wheels, e.g. on king-pins the pivotal axes being situated in more than one plane transverse to the longitudinal centre line of the vehicle, e.g. all-wheel steering specially adapted for particular vehicles, e.g. tractors, carts, earth-moving vehicles, trucks
Abstract
A multi-mode steering system is characterized in that an oil outlet of a hydraulic pump is connected with a port P of a priority valve, and a port CF and a port LS of the priority valve are respectively connected with the port P and the port LS of a hydraulic steering gear; the EF port of the priority valve is connected with the energy accumulator through a third reversing valve; the port A of the steering gear is respectively connected with the port A of the first constant-differential pressure reducing valve and the port A of the fifth reversing valve, and the port B of the steering gear is respectively connected with the port A of the second constant-differential pressure reducing valve and the port A of the fourth reversing valve; the port B of the fourth reversing valve, the port B of the fifth reversing valve and the pressure detection device are connected with the energy accumulator; the ports B of the first constant-differential-pressure reducing valve and the second constant-differential-pressure reducing valve are respectively connected with the ports P of the first reversing valve and the second reversing valve; the T ports of the first reversing valve and the second reversing valve are interconnected; the first reversing valve is connected with the front wheel steering hydraulic cylinder through a first hydraulic control one-way valve group; and the second reversing valve is connected with the rear wheel steering hydraulic cylinder through a second hydraulic control one-way valve group. The system adopts a hydraulic transmission mode, the steering mode is flexible, the turning and turning around are easy, and meanwhile, the operation process is convenient.
Description
Technical Field
The invention relates to the technical field of agricultural planting machinery, in particular to a multi-mode steering system.
Background
With the continuous progress of agricultural modernization, agricultural production is developed from the traditional extensive type to the direction of refinement and intellectualization, the existing agricultural machinery mostly adopts a front wheel steering mode, and part of the machine types adopt a four-wheel steering mode. Meanwhile, because the area of the farmland in China is relatively small, the steering range of the agricultural machinery operation is limited, and the harsher requirement is put forward on the steering maneuverability of the agricultural machinery. Therefore, research into a multi-mode steering system suitable for agricultural machines is urgently required.
Disclosure of Invention
Aiming at the problems in the prior art, the invention provides a multi-mode steering system which adopts a hydraulic transmission mode, has flexible steering mode, easy turning around, small damage degree of a seedling bed in the steering process and convenient operation process.
In order to achieve the purpose, the invention provides a multi-mode steering system which comprises a hydraulic pump, an oil tank, a priority valve, a hydraulic steering gear, an overflow valve, a third reversing valve, a first fixed-difference pressure reducing valve, a fifth reversing valve, a second fixed-difference pressure reducing valve, a fourth reversing valve, a pressure detection device, a front wheel steering hydraulic cylinder, a first reversing valve, a second reversing valve, a first hydraulic control one-way valve group, a first shuttle valve, a second hydraulic control one-way valve group, a rear wheel steering hydraulic cylinder and a second shuttle valve;
an oil inlet and an oil outlet of the hydraulic pump are respectively connected with the oil tank and the P port of the priority valve, and the oil outlet of the hydraulic pump is also connected with the oil tank through a safety valve; the CF port and the LS port of the priority valve are respectively connected with the P port and the LS port of the hydraulic steering gear, and the P port of the priority valve is connected with the CF port of the priority valve through an overflow valve; the EF port of the priority valve is connected with the A port of the third reversing valve; the port A of the steering gear is respectively connected with the port A of the first constant-pressure-difference pressure-reducing valve and the port A of the fifth reversing valve; the port B of the steering gear is respectively connected with the port A of the second constant-differential-pressure reducing valve and the port A of the fourth reversing valve; the port B of the third reversing valve, the port B of the fourth reversing valve, the port B of the fifth reversing valve and the pressure detection device are all connected with the energy accumulator;
the port B of the first constant-differential-pressure reducing valve and the port B of the second constant-differential-pressure reducing valve are respectively connected with the port P of the first reversing valve and the port P of the second reversing valve; the T port of the first reversing valve is connected with the T port of the second reversing valve; the port A and the port B of the first reversing valve are respectively connected with the port A1 and the port A2 of the first hydraulic control check valve group, and the port B1 and the port B2 of the first hydraulic control check valve group are respectively connected with the port A and the port B of the front wheel steering hydraulic cylinder; the port A and the port B of the first shuttle valve are respectively connected with the port A and the port B of the first reversing valve, and the port C of the first shuttle valve is connected with the port X of the first fixed differential pressure reducing valve; the port A and the port B of the second reversing valve are respectively connected with the port A1 and the port A2 of the second hydraulic check valve group, and the port B1 and the port B2 of the second hydraulic check valve group are respectively connected with the port A and the port B of the rear wheel steering hydraulic cylinder; the port A and the port B of the second shuttle valve are respectively connected with the port A and the port B of the second reversing valve, and the port C of the second shuttle valve is connected with the port X of the second constant differential pressure reducing valve;
the front wheel steering hydraulic cylinder and the rear wheel steering hydraulic cylinder are double-piston rod double-acting symmetrical hydraulic cylinders.
The device also comprises a controller and a control box;
the front wheel steering hydraulic cylinder and the rear wheel steering hydraulic cylinder are respectively connected with a stay wire type displacement sensor A and a stay wire type displacement sensor B; the stay wire type displacement sensors A and B are respectively used for acquiring a stroke signal A of the front wheel steering hydraulic cylinder and a stroke signal B of the rear wheel steering hydraulic cylinder in real time and sending the stroke signals A and B to the controller in real time;
the pressure detection device is used for acquiring a pressure signal of the energy accumulator in real time and sending the pressure signal to the controller in real time;
the control box is at least provided with a front wheel steering mode button, a rear wheel steering mode button and a four-wheel steering mode button which are respectively used for sending a front wheel steering mode signal, a rear wheel steering mode signal and a four-wheel steering mode signal to the controller according to the control of an operator;
the controller is respectively connected with the stay wire type displacement sensor A, the stay wire type displacement sensor B, the pressure detection device, the first reversing valve, the second reversing valve, the third reversing valve, the fourth reversing valve, the fifth reversing valve and the control box; the system is used for obtaining travel information A and travel information B according to the received travel signals A and B; the pressure value acquisition module is used for acquiring a pressure value according to the received pressure signal, controlling the third reversing valve to be powered on, the fourth reversing valve to be powered off and the fifth reversing valve to be powered off when the pressure value is smaller than a set pressure value, and controlling the third reversing valve to be powered off when the pressure value is larger than or equal to the set pressure value; the control device is used for controlling the first reversing valve to be electrified to work at an upper position or a lower position and controlling the second reversing valve to be not electrified when a front wheel steering mode signal is received, so that steering action is realized only through the front wheel; the control device is used for controlling the second reversing valve to be electrified to work at an upper position or a lower position and controlling the first reversing valve to be not electrified when a rear wheel steering mode signal is received, so that steering action is realized only through the front wheel; the control device is used for simultaneously controlling the first reversing valve and the second reversing valve to be simultaneously powered on to work at an upper position or simultaneously controlling the first reversing valve and the second reversing valve to be simultaneously powered on to work at a lower position when a four-wheel steering mode signal is received, and controlling the first reversing valve to be powered off, the third reversing valve to be powered off, the fifth reversing valve to be powered off, the fourth reversing valve to be powered on and the second reversing valve to be powered on when the front-wheel steering mode signal is received and then the four-wheel steering mode signal is received within a set time; and when the rear wheel steering mode signal is received first and then the four-wheel steering mode signal is received within the set time, the second reversing valve is controlled to be powered off, the third reversing valve is controlled to be powered off, the fifth reversing valve is controlled to be powered on, the fourth reversing valve is controlled to be powered off, and the first reversing valve is controlled to be powered on, so that the front wheel steering hydraulic cylinder and the rear wheel steering hydraulic cylinder keep synchronous action according to the matching of the received stroke information B and the stroke information A, and the four-wheel steering action is conveniently realized.
The first hydraulic control one-way valve group consists of a first hydraulic control one-way valve and a second hydraulic control one-way valve, an oil inlet and an oil outlet of the first hydraulic control one-way valve are respectively connected with an A port and a B port of the first hydraulic control one-way valve group, an oil inlet and an oil outlet of the second hydraulic control one-way valve are respectively connected with the A port and the B port of the first hydraulic control one-way valve group, and a hydraulic control port of the first hydraulic control one-way valve and a hydraulic control port of the second hydraulic control one-way valve are respectively connected with an oil inlet of the second hydraulic control one-way valve and an oil inlet of the first hydraulic control one-way valve;
the second hydraulic control check valve group consists of a third hydraulic control check valve and a fourth hydraulic control check valve, an oil inlet and an oil outlet of the third hydraulic control check valve are respectively connected with an A port and a B port of the second hydraulic control check valve group, an oil inlet and an oil outlet of the fourth hydraulic control check valve are respectively connected with an A port and a B port of the second hydraulic control check valve group, and a hydraulic control port of the third hydraulic control check valve and a hydraulic control port of the fourth hydraulic control check valve are respectively connected with an oil inlet of the fourth hydraulic control check valve and an oil inlet of the third hydraulic control check valve.
Further, in order to effectively filter oil entering the system, the hydraulic pump is connected with the oil tank through a filter.
Preferably, the controller is a PLC controller.
Preferably, the third reversing valve, the fourth reversing valve and the fifth reversing valve are two-position two-way electromagnetic reversing valves; the third reversing valve works in the left position after being electrified, works in the right position after being electrified, when the third reversing valve works in the right position, the oil way between the port A and the port B is disconnected, and when the third reversing valve works in the left position, the oil way between the port A and the port B is communicated; the fourth reversing valve works in the left position after being electrified, works in the right position after being electrified, when the fourth reversing valve works in the left position, the oil path between the port A and the port B is communicated, and when the fourth reversing valve works in the right position, the oil path between the port A and the port B is disconnected; the fifth reversing valve works in the lower position after being electrified, works in the upper position when the fifth reversing valve is electrified, the oil way between the port A and the port B is communicated when the fifth reversing valve works in the lower position, and the oil way between the port A and the port B is disconnected when the fifth reversing valve works in the upper position.
Preferably, the first reversing valve is a three-position four-way electromagnetic reversing valve, when the first reversing valve works in an upper position by electrifying, an oil path between the port P and the port A is communicated, and an oil path between the port T and the port B is communicated; when the power-off work is in the middle position, the port P and the port T are communicated with each other, and the port A and the port B are cut off from each other; when the electric motor works at the lower position, the oil passages between the ports P and B are communicated, and the oil passages between the ports T and A are communicated; the second reversing valve is a three-position four-way electromagnetic reversing valve, when the second reversing valve works in the lower position by power, the oil path between the port P and the port B is communicated, and the oil path between the port T and the port A is communicated; when the power-off work is in the middle position, the port P and the port T are communicated with each other, and the port A and the port B are cut off from each other; when the electric motor works at an upper position, the oil passages between the port P and the port A are communicated, and the oil passages between the port T and the port B are communicated.
In the invention, the priority valve is load-sensitive, and can automatically adjust the flow according to the system requirement, if the steering wheel rotates rapidly, the flow is large, otherwise, the flow is small; the hydraulic steering gear has the advantages that the hydraulic steering gear can be matched with a load sensitive hydraulic steering gear to be used through the arrangement of the priority valve, the working pressure of a steering system can be obtained in real time through the LS oil port of the priority valve, the flow requirement of a steering oil circuit of the hydraulic steering gear can be guaranteed firstly, the oil supply of the hydraulic steering gear can be preferentially supplied to a front wheel steering loop, and the steering sensitivity is guaranteed. The fixed differential pressure reducing valve is matched with the shuttle valve to realize pressure compensation, and the shuttle valve introduces the pressure of the high-pressure oil line into an X port (one side of the spring cavity) of the fixed differential pressure reducing valve, so that the flow of the first reversing valve and the flow of the second reversing valve are not influenced by the load size and are only related to the opening degree of the first reversing valve and the second reversing valve, and the control precision of the system is further improved. Through the arrangement of the controller and the control box, the convenient switching among a front wheel steering mode, a rear wheel steering mode and a four-wheel steering mode can be conveniently realized, and the steering flexibility is further improved; meanwhile, the priority valve EF oil port can charge the energy accumulator with redundant flow, so that the system efficiency is improved, and meanwhile, the situation that oil overflows and heats is avoided; through the arrangement of the controller and the control box, the access time of the energy accumulator can be reasonably controlled, so that the combination of multiple steering modes can be realized on the premise of only utilizing one hydraulic pump and a steering gear; meanwhile, the on-off of the reversing valve can be conveniently controlled according to the displacement information of the steering hydraulic cylinder, so that the steering state of the system is automatically adjusted, and the steering state can accord with the Ackerman steering principle; the hydraulic control check valve group can accurately lock the position of the hydraulic cylinder, and the hydraulic cylinder cannot be displaced due to external load. The system adopts a hydraulic transmission mode, has flexible steering mode, easy turning around, small damage degree of the seedling bed in the steering process and convenient operation process.
Drawings
FIG. 1 is a hydraulic schematic of the present invention;
FIG. 2 is a schematic view of the steering of the front wheels of the present invention;
FIG. 3 is a schematic view of the steering of the rear wheels of the present invention;
fig. 4 is a schematic view of four wheel steering in the present invention.
In the figure: 1. the hydraulic control system comprises an oil tank, 2, a filter, 3, a hydraulic pump, 4, a safety valve, 5, an overflow valve, 6, a priority valve, 7, a steering valve, 8, a metering motor, 9, a first constant-pressure-difference pressure-reducing valve, 10, a first reversing valve, 11, a first shuttle valve, 12, a first hydraulic one-way valve group, 13, a front wheel steering hydraulic cylinder, 14, a hydraulic steering gear, 15, a fifth reversing valve, 16, a second constant-pressure-difference pressure-reducing valve, 17, a second reversing valve, 18, a second shuttle valve, 19, a second hydraulic one-way valve group, 20, a rear wheel steering hydraulic cylinder, 21, an energy accumulator, 22, a third reversing valve, 23, a pressure detection device, 24 and a fourth reversing valve.
Detailed Description
The invention will be further explained with reference to the drawings.
As shown in fig. 1 to 4, the present invention provides a multi-mode steering system, which includes a hydraulic pump 3, an oil tank 1, a priority valve 6, a hydraulic steering gear 14, an overflow valve 5, a third directional control valve 22, a first differential pressure reducing valve 9, a fifth directional control valve 15, a second differential pressure reducing valve 16, a fourth directional control valve 24, a pressure detection device 23, a first directional control valve 10, a second directional control valve 17, a first pilot operated check valve group 12, a front wheel steering hydraulic cylinder 13, a first shuttle valve 11, a second pilot operated check valve group 19, a rear wheel steering hydraulic cylinder 20, and a second shuttle valve 18;
an oil inlet and an oil outlet of the hydraulic pump 3 are respectively connected with the oil tank 1 and a P port of the priority valve 6, and the oil outlet of the hydraulic pump 3 is also connected with the oil tank 1 through a safety valve 4; the CF port and the LS port of the priority valve 6 are respectively connected with the P port and the LS port of the hydraulic steering gear 14, and the P port of the priority valve 6 is connected with the CF port of the priority valve 6 through an overflow valve 5; the EF port of the priority valve 6 is connected to the a port of the third change valve 22; the port A of the steering gear 14 is respectively connected with the port A of the first constant-pressure-difference pressure-reducing valve 9 and the port A of the fifth reversing valve 15; the port B of the steering gear 14 is respectively connected with the port A of the second constant-differential-pressure reducing valve 16 and the port A of the fourth reversing valve 24; the port B of the third reversing valve 22, the port B of the fourth reversing valve 24, the port B of the fifth reversing valve 15 and the pressure detection device 23 are all connected with the energy accumulator 21;
the port B of the first constant-differential-pressure reducing valve 9 and the port B of the second constant-differential-pressure reducing valve 16 are respectively connected with the port P of the first reversing valve 10 and the port P of the second reversing valve 17; the T port of the first reversing valve 10 is connected with the T port of the second reversing valve 17; the port A and the port B of the first reversing valve 10 are respectively connected with the port A1 and the port A2 of the first pilot-controlled check valve group 12, and the port B1 and the port B2 of the first pilot-controlled check valve group 12 are respectively connected with the port A and the port B of the front wheel steering hydraulic cylinder 13; the port A and the port B of the first shuttle valve 11 are respectively connected with the port A and the port B of the first reversing valve 10, and the port C of the first shuttle valve 11 is connected with the port X of the first fixed differential pressure reducing valve 9; the port A and the port B of the second reversing valve 17 are respectively connected with the port A1 and the port A2 of the second hydraulic check valve group 19, and the port B1 and the port B2 of the second hydraulic check valve group 19 are respectively connected with the port A and the port B of the rear wheel steering hydraulic cylinder 20; the port A and the port B of the second shuttle valve 18 are respectively connected with the port A and the port B of the second reversing valve 17, and the port C of the second shuttle valve 18 is connected with the port X of the second constant-differential-pressure reducing valve 16;
the front wheel steering hydraulic cylinder 13 and the rear wheel steering hydraulic cylinder 20 are both double-piston rod double-acting symmetrical hydraulic cylinders.
The device also comprises a controller and a control box;
the front wheel steering hydraulic cylinder 13 and the rear wheel steering hydraulic cylinder 20 are respectively connected with stay wire type displacement sensors A and B; the stay wire type displacement sensors A and B are respectively used for acquiring a stroke signal A of the front wheel steering hydraulic cylinder 13 and a stroke signal B of the rear wheel steering hydraulic cylinder 20 in real time and sending the stroke signals A and B to the controller in real time;
the pressure detection device 23 is used for acquiring a pressure signal of the energy accumulator 21 in real time and sending the pressure signal to the controller in real time;
the control box is at least provided with a front wheel steering mode button, a rear wheel steering mode button and a four-wheel steering mode button which are respectively used for sending a front wheel steering mode signal, a rear wheel steering mode signal and a four-wheel steering mode signal to the controller according to the control of an operator;
the controller is respectively connected with the stay wire type displacement sensor A, the stay wire type displacement sensor B, the pressure detection device 23, the first reversing valve 10, the second reversing valve 17, the third reversing valve 22, the fourth reversing valve 24, the fifth reversing valve 15 and the control box; the system is used for obtaining travel information A and travel information B according to the received travel signals A and B; the pressure value acquisition module is used for acquiring a pressure value according to the received pressure signal, controlling the third reversing valve 22 to be powered on, the fourth reversing valve 24 to be powered off and the fifth reversing valve 15 to be powered off when the pressure value is smaller than a set pressure value, and controlling the third reversing valve 22 to be powered off when the pressure value is larger than or equal to the set pressure value; when a front wheel steering mode signal is received, the first reversing valve 10 is controlled to be electrified to work at an upper position or a lower position, and the second reversing valve 17 is controlled not to be electrified, so that the steering action is realized only through the front wheels; the control device is used for controlling the second reversing valve 17 to be electrified to work at an upper position or a lower position and controlling the first reversing valve 10 not to be electrified when receiving a rear wheel steering mode signal so as to realize steering action only through the front wheels; the control device is used for simultaneously controlling the first reversing valve 10 and the second reversing valve 17 to be powered on and work at an upper position when receiving a four-wheel steering mode signal, or simultaneously controlling the first reversing valve 10 and the second reversing valve 17 to be powered on and work at a lower position when receiving the four-wheel steering mode signal after receiving a front-wheel steering mode signal in a set time, and controlling the third reversing valve 22 to be powered off, the fifth reversing valve 15 to be powered off and the fourth reversing valve 24 to be powered on when receiving the four-wheel steering mode signal; when the rear wheel steering mode signal is received first and then the four-wheel steering mode signal is received within a set time, the third reversing valve 22 is controlled to be powered off, the fifth reversing valve 15 is controlled to be powered on, the fourth reversing valve 24 is controlled to be powered off, and the front wheel steering hydraulic cylinder 13 and the rear wheel steering hydraulic cylinder 20 keep synchronous action according to the matching of the received stroke information B and the stroke information A, so that the four-wheel steering action is realized.
The first hydraulic control one-way valve group 12 consists of a first hydraulic control one-way valve and a second hydraulic control one-way valve, an oil inlet and an oil outlet of the first hydraulic control one-way valve are respectively connected with an A1 port and a B1 port of the first hydraulic control one-way valve group 12, an oil inlet and an oil outlet of the second hydraulic control one-way valve are respectively connected with an A2 port and a B2 port of the first hydraulic control one-way valve group 12, and a hydraulic control port of the first hydraulic control one-way valve and a hydraulic control port of the second hydraulic control one-way valve are respectively connected with an oil inlet of the second hydraulic control one-way valve and an oil inlet of the first hydraulic control one-way valve;
the second hydraulic control one-way valve group 19 is composed of a third hydraulic control one-way valve and a fourth hydraulic control one-way valve, an oil inlet and an oil outlet of the third hydraulic control one-way valve are respectively connected with an A1 port and a B1 port of the second hydraulic control one-way valve group 19, an oil inlet and an oil outlet of the fourth hydraulic control one-way valve are respectively connected with an A2 port and a B2 port of the second hydraulic control one-way valve group 19, and a hydraulic control port of the third hydraulic control one-way valve and a hydraulic control port of the fourth hydraulic control one-way valve are respectively connected with an oil inlet of the fourth hydraulic control one-way valve and an oil inlet of the third hydraulic control one-way valve.
For effective filtration of the oil entering the system, the hydraulic pump 3 is connected to the oil tank 1 via a filter 2.
Preferably, the controller is a PLC controller.
Preferably, the third direction valve 22, the fourth direction valve 24 and the fifth direction valve 15 are two-position two-way electromagnetic direction valves; the third reversing valve 22 works in the left position after being electrified, works in the right position after being electrified, when the third reversing valve works in the right position, the oil path between the port A and the port B is disconnected, and when the third reversing valve works in the left position, the oil path between the port A and the port B is communicated; the fourth reversing valve 24 works in the left position after being electrified, works in the right position after being electrified, when the fourth reversing valve works in the left position, the oil path between the port A and the port B is communicated, and when the fourth reversing valve works in the right position, the oil path between the port A and the port B is disconnected; the fifth directional control valve 15 is operated in the lower position after being energized, in the upper position when de-energized, and in the lower position, the oil path between the port a and the port B is communicated, and in the upper position, the oil path between the port a and the port B is disconnected.
Preferably, the first directional valve 10 is a three-position four-way electromagnetic directional valve, when the valve is powered on and works in an upper position, the oil path between the port P and the port a is communicated, and the oil path between the port T and the port B is communicated; when the power-off work is in the middle position, the port P and the port T are communicated with each other, and the port A and the port B are cut off from each other; when the electric motor works at the lower position, the oil passages between the ports P and B are communicated, and the oil passages between the ports T and A are communicated; the second reversing valve 17 is a three-position four-way electromagnetic reversing valve, and when the second reversing valve works in the lower position by being electrified, the oil path between the port P and the port B is communicated, and the oil path between the port T and the port A is communicated; when the power-off work is in the middle position, the port P and the port T are communicated with each other, and the port A and the port B are cut off from each other; when the electric motor works at an upper position, the oil passages between the port P and the port A are communicated, and the oil passages between the port T and the port B are communicated.
The working principle is as follows:
the engine provides power for a hydraulic system, the engine drives a hydraulic pump 3 to rotate through a coupler, an oil suction port of the hydraulic pump 3 sucks oil from an oil tank 1 through a filter 2, the filter 2 can ensure better oil cleanliness, an oil outlet of the hydraulic pump 3 is connected with a priority valve 6, a main oil port (CF oil port) of the priority valve 6 is connected with a P port of a hydraulic steering gear 14, the hydraulic steering gear 14 mainly comprises a steering valve 7 and a metering motor 8, an LS port (pressure sensing oil port) of the priority valve 6 can obtain working pressure of the hydraulic steering gear 14 in real time and feed the pressure back to the priority valve 6 to realize load sensitive control, so that when a steering wheel rotates fast, an opening of the hydraulic steering gear 14 is large, a steering hydraulic cylinder acts fast, when the steering wheel rotates slowly, the opening of the hydraulic steering gear 14 is small, the hydraulic cylinder operates slowly, the A port and the B port of the hydraulic steering gear 14 are respectively connected with an A port of a first constant differential pressure reducing valve 9 and an A port of a second constant differential pressure reducing valve 16, the first and second shuttle valves 11 and 18 can introduce the pressure on the high-pressure side of the actuator back to the X port (spring chamber side) of the constant-differential pressure-reducing valve, and the first and second constant-differential pressure-reducing valves 9 and 11, the second constant-differential pressure-reducing valve 16 and the second shuttle valve 18 constitute two sets of pressure compensators which can ensure that the passing flow of the first and second direction-changing valves 10 and 17 is only related to the opening degree of the internal valve ports thereof, regardless of the load pressure. The pressure compensator ensures that the flow through the cylinders is accurately controlled when the load on the cylinders of the front and rear wheels is not the same, such as when the machine turns around on a slope.
The first reversing valve 10 and the second reversing valve 17 both adopt an M-type neutral position function, namely when the neutral position is accessed, the system can be unloaded. The oil outlet of the first reversing valve 10 is connected with a first hydraulic control one-way valve group 12, the oil outlet of the second reversing valve 17 is connected with a second hydraulic control one-way valve group 19, the hydraulic control one-way valve group is used for locking a front wheel steering hydraulic cylinder 13 and a rear wheel steering hydraulic cylinder 20 (front wheel steering executing elements and rear wheel steering executing elements) which correspond to the steering hydraulic cylinders when the steering hydraulic cylinders do not work, the two hydraulic cylinders are both provided with stay wire type displacement sensors, and a controller can determine the positions of the hydraulic cylinders and the steering mode of the system according to feedback information of the stay wire type displacement sensors.
An EF port (an auxiliary oil port) of the priority valve 6 is connected with an A port (an oil inlet) of the third reversing valve 22, and a B port (an oil outlet) of the third reversing valve 22 is respectively connected with an energy accumulator 21, a pressure detection device 23, a B port of the fourth reversing valve 24 and a B port of the fifth reversing valve 15. The pressure detection device 23 can measure the pressure of the energy accumulator 21 in real time, when the pressure of the energy accumulator 21 is lower than a set pressure value, the controller controls the third reversing valve 22 to be electrified, the fourth reversing valve 24 and the fifth reversing valve 15 are powered off, and the system charges the energy accumulator 21. When the pressure of the accumulator 21 is higher than the set pressure value, the controller controls the third reversing valve 22 to be powered off, and controls the working states of the fourth reversing valve 24 and the fifth reversing valve 15 according to actual requirements.
When the system is in front wheel steering, namely in the state shown in FIG. 2, the controller controls the front wheel steering hydraulic cylinder 13 to work by controlling the first direction-changing valve 10, and the second direction-changing valve 17 is in a neutral position; when the system is in the rear wheel steering state, namely the state shown in figure 3, the controller controls the rear wheel steering hydraulic cylinder 20 to work by controlling the second reversing valve 17, the first reversing valve 10 is in the neutral position, when the system is in the four-wheel steering state, namely the state shown in figure 4, the first reversing valve 10 and the second reversing valve 17 connect the two hydraulic cylinders of the front wheel steering hydraulic cylinder 13 and the rear wheel steering hydraulic cylinder 20 in series (simultaneously electrifying the left position or the right position), and at the same time, the two steering hydraulic cylinders are connected in series, and the flow and the displacement are completely consistent. When the system is switched from two-wheel steering to four-wheel steering, assuming that the steering angle of the front wheels is not 0 and the steering angle of the rear wheels is 0, (i.e. the steering mode of the front wheels is switched to the four-wheel steering and the front wheels are steered), at this time, the controller controls the first reversing valve 10 to be powered off, the third reversing valve 22 to be powered off, the fifth reversing valve 15 to be powered off, the fourth reversing valve 24 to be powered on, the accumulator 21 provides power for the hydraulic system of the rear wheel steering, the controller determines whether the second reversing valve 17 is connected to the upper position or the lower position of the system according to the information fed back by the pull wire type displacement sensor, and adjusts the hydraulic cylinder 20 of the rear wheel steering to a proper position based on the PID control algorithm, so that the steering system meets the Ackerman steering principle (the basic requirement that each wheel of a wheeled vehicle completes steering is pure rolling, i.e. each wheel axis of the vehicle is required to pass through the same instant axis when the vehicle is steered, which condition is called the Ackerman steering theorem at a low vehicle speed, and the slip angle is close to 0, in which case there are no mutually balanced lateral and centrifugal forces. ) After the adjustment is completed, the upper computer (such as a touch screen) can display the information of the adjustment completion, and the upper computer is in real-time communication with the controller. Assuming that the steering angle of the front wheel is 0 and the steering angle of the rear wheel is not 0, (namely, the rear wheel steering mode is switched to the four-wheel steering mode and the rear wheel is steered), at the moment, the controller controls the second reversing valve 17 to be powered off, the third reversing valve 22 to be powered off, the fourth reversing valve 24 to be powered off and the fifth reversing valve 15 to be powered on, the energy accumulator 21 provides power for the front wheel steering hydraulic system, the controller controls the left position or the right position of the first reversing valve 10 to be connected into the system according to information fed back by the stay wire type displacement sensor, and adjusts the front wheel steering hydraulic cylinder 13 to a proper position based on a PID control algorithm, so that the steering system meets the Ackerman steering principle, after the adjustment is completed, an upper computer (such as a touch screen) can display the information of the completion of the adjustment, and the upper computer is in real-time communication with the controller.
Claims (7)
1. A multi-mode steering system comprises a hydraulic pump (3) and an oil tank (1), and is characterized by further comprising a priority valve (6), a hydraulic steering gear (14), an overflow valve (5), a third reversing valve (22), a first constant-difference pressure reducing valve (9), a fifth reversing valve (15), a second constant-difference pressure reducing valve (16), a fourth reversing valve (24), a pressure detection device (23), a front-wheel steering hydraulic cylinder (13), a first reversing valve (10), a second reversing valve (17), a first hydraulic control one-way valve group (12), a first shuttle valve (11), a second hydraulic control one-way valve group (19), a rear-wheel steering hydraulic cylinder (20) and a second shuttle valve (18);
an oil inlet and an oil outlet of the hydraulic pump (3) are respectively connected with the oil tank (1) and a P port of the priority valve (6), and the oil outlet of the hydraulic pump (3) is also connected with the oil tank (1) through a safety valve (4); the CF port and the LS port of the priority valve (6) are respectively connected with the P port and the LS port of the hydraulic steering gear (14), and the P port of the priority valve (6) is connected with the CF port of the priority valve (6) through an overflow valve (5); the EF port of the priority valve (6) is connected with the A port of the third reversing valve (22); the port A of the steering gear (14) is respectively connected with the port A of the first constant-differential-pressure relief valve (9) and the port A of the fifth reversing valve (15); the port B of the steering gear (14) is respectively connected with the port A of the second constant-differential-pressure relief valve (16) and the port A of the fourth reversing valve (24); the port B of the third reversing valve (22), the port B of the fourth reversing valve (24), the port B of the fifth reversing valve (15) and the pressure detection device (23) are connected with the energy accumulator (21);
the port B of the first constant-differential-pressure reducing valve (9) and the port B of the second constant-differential-pressure reducing valve (16) are respectively connected with the port P of the first reversing valve (10) and the port P of the second reversing valve (17); the T port of the first reversing valve (10) is connected with the T port of the second reversing valve (17); the port A and the port B of the first reversing valve (10) are respectively connected with the port A1 and the port A2 of the first pilot-controlled check valve group (12), and the port B1 and the port B2 of the first pilot-controlled check valve group (12) are respectively connected with the port A and the port B of the front wheel steering hydraulic cylinder (13); the port A and the port B of the first shuttle valve (11) are respectively connected with the port A and the port B of the first reversing valve (10), and the port C of the first shuttle valve (11) is connected with the port X of the first constant-differential pressure-reducing valve (9); the port A and the port B of the second reversing valve (17) are respectively connected with the port A1 and the port A2 of the second hydraulic check valve group (19), and the port B1 and the port B2 of the second hydraulic check valve group (19) are respectively connected with the port A and the port B of the rear wheel steering hydraulic cylinder (20); the port A and the port B of the second shuttle valve (18) are respectively connected with the port A and the port B of the second reversing valve (17), and the port C of the second shuttle valve (18) is connected with the port X of the second constant-differential pressure-reducing valve (16);
the front wheel steering hydraulic cylinder (13) and the rear wheel steering hydraulic cylinder (20) are both double-piston rod double-acting symmetrical hydraulic cylinders.
2. A multi-mode steering system according to claim 1, further comprising a controller and a control box;
the front wheel steering hydraulic cylinder (13) and the rear wheel steering hydraulic cylinder (20) are respectively connected with a stay wire type displacement sensor A and a stay wire type displacement sensor B; the stay wire type displacement sensors A and B are respectively used for acquiring a stroke signal A of the front wheel steering hydraulic cylinder (13) and a stroke signal B of the rear wheel steering hydraulic cylinder (20) in real time and sending the stroke signals A and B to the controller in real time;
the pressure detection device (23) is used for acquiring a pressure signal of the energy accumulator (21) in real time and sending the pressure signal to the controller in real time;
the control box is at least provided with a front wheel steering mode button, a rear wheel steering mode button and a four-wheel steering mode button which are respectively used for sending a front wheel steering mode signal, a rear wheel steering mode signal and a four-wheel steering mode signal to the controller according to the control of an operator;
the controller is respectively connected with the stay wire type displacement sensor A, the stay wire type displacement sensor B, the pressure detection device (23), the first reversing valve (10), the second reversing valve (17), the third reversing valve (22), the fourth reversing valve (24), the fifth reversing valve (15) and the control box; the system is used for obtaining travel information A and travel information B according to the received travel signals A and B; the pressure value acquisition device is used for acquiring a pressure value according to the received pressure signal, controlling the third reversing valve (22) to be powered on, the fourth reversing valve (24) to be powered off and the fifth reversing valve (15) to be powered off when the pressure value is smaller than a set pressure value, and controlling the third reversing valve (22) to be powered off when the pressure value is larger than or equal to the set pressure value; when a front wheel steering mode signal is received, the first reversing valve (10) is controlled to be electrified to work at an upper position or a lower position, and the second reversing valve (17) is controlled not to be electrified, so that steering action is realized only through the front wheels; when a rear wheel steering mode signal is received, the second reversing valve (17) is controlled to be electrified to work at an upper position or a lower position, and the first reversing valve (10) is controlled not to be electrified, so that steering action is realized only through the front wheels; the four-wheel steering control system is used for simultaneously controlling the first reversing valve (10) and the second reversing valve (17) to be simultaneously powered on to work at an upper position when a four-wheel steering mode signal is received, or simultaneously controlling the first reversing valve (10) and the second reversing valve (17) to be powered on to work at a lower position, and controlling the first reversing valve (10) to be powered off, the third reversing valve (22) to be powered off, the fifth reversing valve (15) to be powered off, the fourth reversing valve (24) to be powered on and the second reversing valve (17) to be powered on when the four-wheel steering mode signal is received after a front-wheel steering mode signal is received in a set time; when a rear wheel steering mode signal is received first and then a four-wheel steering mode signal is received within a set time, the second reversing valve (17) is controlled to be powered off, the third reversing valve (22) is controlled to be powered off, the fifth reversing valve (15) is powered on, the fourth reversing valve (24) is controlled to be powered off, and the front wheel steering hydraulic cylinder (13) and the rear wheel steering hydraulic cylinder (20) keep synchronous action according to the fact that the received stroke information B is matched with the stroke information A, so that four-wheel steering action is achieved.
3. The multi-mode steering system according to claim 1 or 2, wherein the first pilot-controlled check valve group (12) is composed of a first pilot-controlled check valve and a second pilot-controlled check valve, an oil inlet and an oil outlet of the first pilot-controlled check valve are respectively connected with the port A1 and the port B1 of the first pilot-controlled check valve group (12), an oil inlet and an oil outlet of the second pilot-controlled check valve are respectively connected with the port A2 and the port B2 of the first pilot-controlled check valve group (12), and a pilot-controlled port of the first pilot-controlled check valve and a pilot-controlled port of the second pilot-controlled check valve are respectively connected with an oil inlet of the second pilot-controlled check valve and an oil inlet of the first pilot-controlled check valve;
the second hydraulic control one-way valve group (19) is composed of a third hydraulic control one-way valve and a fourth hydraulic control one-way valve, the oil inlet and the oil outlet of the third hydraulic control one-way valve are respectively connected with the port A1 and the port B1 of the second hydraulic control one-way valve group (19), the oil inlet and the oil outlet of the fourth hydraulic control one-way valve are respectively connected with the port A2 and the port B2 of the second hydraulic control one-way valve group (19), and the hydraulic control port of the third hydraulic control one-way valve and the hydraulic control port of the fourth hydraulic control one-way valve are respectively connected with the oil inlet of the fourth hydraulic control one-way valve and the oil inlet of the third hydraulic control one-way valve.
4. A multi-mode steering system according to claim 3, characterized in that the hydraulic pump (3) is connected to the oil tank (1) via a filter (2).
5. A multi-mode steering system according to claim 2, wherein said controller is a PLC controller.
6. A multi-mode steering system according to claim 5, wherein the third directional control valve (22), the fourth directional control valve (24) and the fifth directional control valve (15) are each two-position two-way solenoid directional control valves; the third reversing valve (22) works in the left position after being electrified, works in the right position after being electrified, when the third reversing valve works in the right position, the oil way between the port A and the port B is disconnected, and when the third reversing valve works in the left position, the oil way between the port A and the port B is communicated; the fourth reversing valve (24) works in the left position after being electrified, works in the right position after being electrified, when the fourth reversing valve works in the left position, the oil circuit between the port A and the port B is communicated, and when the fourth reversing valve works in the right position, the oil circuit between the port A and the port B is disconnected; the fifth reversing valve (15) works at the lower position after being electrified, works at the upper position when being electrified, the oil way between the port A and the port B is communicated when the fifth reversing valve works at the lower position, and the oil way between the port A and the port B is disconnected when the fifth reversing valve works at the upper position.
7. A multi-mode steering system according to claim 6, wherein the first directional control valve (10) is a three-position four-way electromagnetic directional control valve, and when it is electrically operated in an up position, the oil path between the port P and the port A is communicated, and the oil path between the port T and the port B is communicated; when the power-off work is in the middle position, the port P and the port T are communicated with each other, and the port A and the port B are cut off from each other; when the electric motor works at the lower position, the oil passages between the ports P and B are communicated, and the oil passages between the ports T and A are communicated; the second reversing valve (17) is a three-position four-way electromagnetic reversing valve, when the second reversing valve works in the lower position by power, the oil path between the port P and the port B is communicated, and the oil path between the port T and the port A is communicated; when the power-off work is in the middle position, the port P and the port T are communicated with each other, and the port A and the port B are cut off from each other; when the electric motor works at an upper position, the oil passages between the port P and the port A are communicated, and the oil passages between the port T and the port B are communicated.
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| Application Number | Priority Date | Filing Date | Title |
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| CN202010731037.7A CN111959604B (en) | 2020-07-27 | 2020-07-27 | Multi-mode steering system |
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| CN202010731037.7A CN111959604B (en) | 2020-07-27 | 2020-07-27 | Multi-mode steering system |
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| CN111959604A CN111959604A (en) | 2020-11-20 |
| CN111959604B true CN111959604B (en) | 2021-10-29 |
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| CN202010731037.7A Active CN111959604B (en) | 2020-07-27 | 2020-07-27 | Multi-mode steering system |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN112810693B (en) * | 2021-01-08 | 2022-03-22 | 三一汽车起重机械有限公司 | Steering system and engineering machinery |
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