CN111845928B - Front axle steering oil tank assembly and steering system - Google Patents

Front axle steering oil tank assembly and steering system Download PDF

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Publication number
CN111845928B
CN111845928B CN202010751005.3A CN202010751005A CN111845928B CN 111845928 B CN111845928 B CN 111845928B CN 202010751005 A CN202010751005 A CN 202010751005A CN 111845928 B CN111845928 B CN 111845928B
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China
Prior art keywords
steering
oil
rear axle
assembly
axle steering
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CN111845928A (en
Inventor
徐晓曦
张勇
赵松
王成玲
刘富强
李玉
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China North Vehicle Research Institute
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China North Vehicle Research Institute
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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
    • B62D5/062—Details, component parts
    • B62D5/064—Pump driven independently from vehicle engine, e.g. electric driven pump
    • 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
    • B62D5/08—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 steering valve used
    • 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
    • B62D7/15—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 characterised by means varying the ratio between the steering angles of the steered wheels
    • B62D7/1554—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 characterised by means varying the ratio between the steering angles of the steered wheels comprising a fluid interconnecting system between the steering control means of the different axles
    • B62D7/1572—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 characterised by means varying the ratio between the steering angles of the steered wheels comprising a fluid interconnecting system between the steering control means of the different axles provided with electro-hydraulic control means

Abstract

The invention provides a front axle steering oil tank assembly which comprises a steering oil tank and an oil tank support, wherein the steering oil tank is fixed on a vehicle body through the oil tank support and is provided with two oil way interfaces, namely an oil outlet and an oil return port, the oil outlet is connected with an oil inlet of a steering pump, and the oil return port is connected with an oil return port T of a hydraulic power steering gear assembly and a No. 2 interface of a rear axle steering integrated valve group. According to the front axle steering oil tank assembly and the steering system thereof, the closed-loop control of the steering hydraulic cylinder and the steering wheel operation and the unlocking and locking control of the passive active steering and rigid locking device of the steering axle can be realized.

Description

Front axle steering oil tank assembly and steering system
The application is a divisional application aiming at 22.4.2019, application number 2019103219846 and invention name 'a rear axle steering integrated valve group and a steering device'.
Technical Field
The invention relates to a high-reliability mechanical-electric-hydraulic all-wheel steering system suitable for wheeled vehicles, and belongs to the field of machinery, hydraulic pressure and motor vehicle application.
Background
The wheel-type equipment is an important component of a military weapon equipment system and is an important land maneuvering platform for realizing the development strategy of 'universe maneuvering, three-dimensional protection and multi-dimensional and multi-energy' of the army, the sea and the air. Vehicle mobility, broadly speaking, refers to the ability to reach space and region quickly, including tactical mobility, strategic/tactical mobility, and for wheeled vehicles, mobility promotion is more focused on improving soft ground, random off-road ground trafficability, plateau mountain driving performance, air transportability, and the like. The essence of the wheel type vehicle steering system is that the degree of coincidence between the vehicle running track and the driver intention in time and space and the stability of the vehicle running state are reflected by taking the vehicle steering radius as a basis. Therefore, the steering maneuverability is a decisive factor influencing the vehicle maneuverability, and the special steering modes such as reducing the low-speed steering radius, enhancing the high-speed stability and providing the diagonal driving through the all-wheel steering technology become effective ways for solving the common problem of improving the maneuverability of the wheeled vehicle worldwide.
(1) The wheel type vehicle, especially the multi-axle wheel type vehicle, can obviously reduce the turning radius when the vehicle is running at low speed through the application of the all-wheel steering system, and improves the vehicle mobility. Internationally, the novel 8X8 wheeled armored vehicle generally improves maneuverability by increasing the 4 th axis steering on the basis of 1 and 2 axis steering, and the steering radius of the vehicle can be reduced by about 30% by adopting the 1, 2, 3 and 4 axis steering in part of vehicle types. Because the vehicle type of a tactical vehicle changes along with a task section, the number of axles, the arrangement form and other factors are complex, and the multi-wheel/all-wheel steering form is complex and various, at the beginning of the design of a system scheme, the influence of the functions of the all-wheel steering system on the vehicle operation stability is generally verified by a forward design method of a virtual road test environment combining the steering system dynamics and the vehicle dynamics, so that the use working condition and the overall scheme are preliminarily determined.
(2) Compared with an engineering vehicle, the wheeled vehicle has more complex working conditions and more severe environment, and the response characteristic and the shock resistance of the follow-up steering axle are common problems influencing the operation stability and the safety of the vehicle. The technical scheme of an electro-hydraulic system is adopted in the all-wheel steering system of the military wheeled vehicle, the system principle, the composition, the using method and the like are all close to the field of engineering vehicles, but the using environment of the military vehicle is more harsh, the nonlinear load borne by a steering axle is rapidly increased under the condition of a low-speed off-road surface, the statistical average value shows that the nonlinear load is usually more than about 3 times of the load of the steering axle, and the response of a follow-up steering axle is greatly influenced, so that an energy storage device and an elastic device are usually added in the all-wheel steering system of the military vehicle, and the problems of low-speed impact resistance and high-speed elimination of high-frequency shimmy are solved.
(3) Under the conditions of mode switching and system failure, the active return-to-center and median steering stiffness of the follow-up steering axle are key technologies for guaranteeing the reliability of the system. Under the condition of complex load, when the functions of the all-wheel steering system are switched or the system is in fault, the follow-up steering axle is required to be automatically aligned and the steering rigidity in a neutral position state is ensured, otherwise the maneuverability and the safety of the vehicle are directly influenced, so that the device capable of realizing the neutral position maintaining and active alignment functions of the follow-up steering axle becomes the important factor for ensuring the reliability and the driving safety of the vehicle.
According to the comparison situation, the changeable vehicle structure, the complex application environment, the harsh use condition and the like of the wheeled vehicle bring great challenges to the reliable application of the all-wheel steering technology on the wheeled vehicle, and the technical framework of the all-wheel steering system of the engineering vehicle cannot meet the use requirements by borrowing and improving, so that the all-wheel steering system which can simultaneously have the dynamic response and the shock resistance of the follow-up steering axle in the complex environment can be used as a high-reliability all-wheel steering system suitable for the wheeled vehicle, and the all-wheel steering system with three core capabilities of neutral steering rigidity and system failure of the follow-up steering axle under the nonlinear load and active return of the follow-up steering axle under the damaged state of the vehicle can be used.
Therefore, the development of a high-reliability electromechanical liquid all-wheel steering system with the passive middle position aligning and rigid locking functions of a steering axle is the most effective way for solving the technical problems.
Disclosure of Invention
The technical problem to be solved by the invention is as follows: how to provide a high reliability electro-hydraulic all-wheel steering system.
In order to achieve the purpose, the technical scheme of the invention is as follows:
a rear axle steering integrated valve group is characterized by comprising a valve body, a three-position four-way proportional reversing valve, two balance valves, four first to fourth two-position two-way electromagnetic valves, two three-position three-way electromagnetic valves and one-way valves; the rear axle steering integrated valve group is provided with 6 oil way interfaces from a first interface to a sixth interface;
the valve body is of a cubic structure and comprises six faces, the two balance valves, the four two-position two-way solenoid valve, the two-position three-way solenoid valve and the one-way valve are located on the first face, the four interfaces of the third interface, the fourth interface, the fifth interface and the sixth interface are located on the second face vertically connected with the first face, the first interface and the second interface are located on the third face connected with the first face and the second face, the fourth face is opposite to the third face, and the three-position four-way proportional reversing valve is located in the middle of the fourth face.
Preferably, on the first surface, the first, second and fourth two-position two-way solenoid valves are located on one side far away from the second surface, and the valves of the fourth, second and first two-position two-way solenoid valves are arranged in sequence from the third surface to the fourth surface; a two-position three-way electromagnetic valve and a third two-position two-way electromagnetic valve are arranged on one side close to the second surface, wherein the third two-position two-way electromagnetic valve and the two-position three-way electromagnetic valve are sequentially arranged from the third surface to the fourth surface, and the third two-position two-way electromagnetic valve and the two-position three-way electromagnetic valve are arranged on one side close to the third surface; the one-way valve is positioned between the third and fourth two-way electromagnetic valves; the two balance valves are positioned between the two-position three-way electromagnetic valve and the fourth surface and between the first two-position two-way electromagnetic valve and the second surface.
Preferably, the third interface and the fourth interface are arranged on one side of the second surface, which is close to the first surface, wherein the third interface and the fourth interface are arranged in sequence from the third surface to the fourth surface; the sixth interface and the fifth interface are arranged on the side far away from the first surface, preferably on the side near the fourth surface, and the sixth interface and the fifth interface are arranged in sequence from the third surface to the fourth surface.
Preferably, on the third surface, the first interface and the second interface are arranged close to the first surface, wherein the first interface is farther away from the second surface than the second interface.
A4X 4 electromechanical liquid all-wheel steering system is characterized by comprising a steering wheel and steering gear assembly, a front axle steering oil tank assembly, a front axle steering pump, a rear axle steering oil tank assembly, a front axle steering rod system, a rear axle steering hydraulic cylinder assembly, a steering return locking mechanism assembly, a rear axle steering integrated valve set, an all-wheel steering controller assembly, a rear axle steering rod system and a rear axle electric steering pump assembly, wherein the steering wheel and steering gear assembly is connected with the front axle steering rod system; the front axle steering pump is arranged on the engine and is driven by the engine to provide a power source for the system; an oil outlet of the front axle steering oil tank assembly is connected with an oil inlet end of a front axle steering pump through an oil pipe, and an oil return port is connected with an oil return port of a steering wheel and a power steering gear assembly in the power steering gear assembly through an oil pipe;
an oil outlet of the rear axle steering oil tank assembly is connected with an oil inlet end of the rear axle electric steering pump assembly through an oil pipe, and an oil return port is connected with an oil return port T of the rear axle steering integrated valve group through an oil pipe; an oil outlet of the rear axle electric steering pump assembly is connected with an oil inlet end of the rear axle steering integrated valve group through an oil pipe; a first interface of a rear axle steering hydraulic cylinder assembly is connected with an A port of a rear axle steering integrated valve group through an oil pipe, a second interface of the rear axle steering hydraulic cylinder assembly is connected with a B port of the rear axle steering integrated valve group through an oil pipe, the rear axle steering hydraulic cylinder assembly is connected with a left swing arm of a rear axle steering rod system, a first interface of an unlocking oil cylinder of a steering return locking mechanism assembly is connected with a P2 port of the rear axle steering integrated valve group through an oil pipe, a second interface of the unlocking oil cylinder of the steering return locking mechanism assembly is connected with a T2 port of the rear axle steering integrated valve group through an oil pipe, and the steering return locking mechanism assembly is connected with a right swing arm of the rear axle steering rod system; the rear axle steering integrated valve group is the rear axle steering integrated valve group.
Preferably, the first interface is an oil inlet port which is connected with an oil outlet of the rear axle steering pump assembly, and the second interface is an oil return port which is connected with an oil return port of the rear axle steering oil tank assembly; the third interface and the fourth interface are respectively connected with a first interface and a second interface of an unlocking oil cylinder of the steering return locking mechanism assembly; the fifth interface and the sixth interface are connected with the first interface and the second interface of the rear axle steering hydraulic cylinder assembly.
Preferably, the rear axle steering integrated valve group is fixed on the vehicle body bottom plate through a through hole in the valve body.
Preferably, the steering return locking mechanism assembly is connected with the right swing arm of the rear axle steering rod system through a ball pin.
Preferably, the steering wheel and steering gear assembly comprises a steering wheel, a combination switch, a first steering transmission shaft, a second steering transmission shaft, a steering wheel angle sensor, an angle transmission box, a middle transmission shaft assembly and a hydraulic power steering gear assembly; the steering wheel is connected with a first steering transmission shaft, and a combined switch bracket is processed in the middle of the first steering transmission shaft and used for mounting a combined switch; the steering wheel rotation angle sensor is arranged on the first steering transmission shaft; the first steering transmission shaft is connected with the second steering transmission shaft, one end of the first steering transmission shaft is connected with the steering wheel, the other end of the first steering transmission shaft is connected with the second steering transmission shaft, the other end of the second steering transmission shaft is connected with the angle transmission box, one end of the middle transmission shaft assembly is connected with the angle transmission box through universal joint spline fit, and the other end of the middle transmission shaft assembly is connected with an input shaft of the hydraulic power steering gear assembly.
Preferably, the hydraulic power steering gear assembly is provided with two oil path interfaces of an oil inlet P and an oil return port T, and the two oil path interfaces are respectively connected with an oil outlet port of the front axle steering pump and an oil return port of the front axle steering oil tank assembly.
Preferably, the rear axle steering integrated valve group comprises a valve body, a three-position four-way proportional reversing valve, two balance valves, four two-position two-way electromagnetic valves, two-position three-way electromagnetic valve valves and a one-way valve; the rear axle steering integrated valve group is fixed on a vehicle body bottom plate through a through hole on the valve body and is provided with 6 oil way interfaces; the first interface is that the oil inlet port P is connected with the oil outlet of the rear axle steering pump assembly, and the second interface is that the oil return port T is connected with the oil return port of the rear axle steering oil tank; the third port P2 and the fourth port T2 are respectively connected with a first port and a second port of an unlocking oil cylinder (44) of the steering return locking mechanism assembly, and the fifth port A and the sixth port B are connected with a first port and a second port of the rear axle steering hydraulic cylinder assembly. Unlocking oil cylinder
Preferably, the rear axle steering hydraulic cylinder comprises a cylinder barrel, a piston rod, a ball head, a clamp and a cylinder displacement sensor, and is provided with a first interface and a second interface which are respectively connected with a fifth interface and a sixth interface of the rear axle steering integrated valve group through oil pipes; the oil cylinder displacement sensor is arranged inside the cylinder barrel; one end of the rear axle steering hydraulic cylinder assembly is connected with the vehicle body auxiliary seat through a joint bearing, the other end of the rear axle steering hydraulic cylinder assembly is connected with a left swing arm of a rear axle steering rod system through a ball head, so that the rear axle steering hydraulic cylinder assembly is fixed, a first interface of an upper oil way of the rear axle steering hydraulic cylinder assembly is connected with a fifth interface of the rear axle steering integrated valve bank, and a second interface of the rear axle steering hydraulic cylinder assembly is connected with a sixth interface of the rear axle steering integrated valve bank.
Preferably, the steering return locking mechanism assembly comprises an unlocking oil cylinder, an unlocking spring, a return spring, a mechanical lock assembly, a rotating pin shaft, a return cylinder, a telescopic shaft, a left support fixing nut, a left spring support assembly, a right spring support assembly, a check ring between cylinder bodies, a pin shaft, an unlocking spring support, an unlocking cylinder upper support, an unlocking cylinder lower support, a ball pin, a locking sensor and an unlocking sensor, wherein the left end and the right end of the return spring are arranged in the return cylinder body through the left spring support assembly and the right spring support assembly, and the return spring is compressed leftwards and rightwards respectively by pushing the left spring support assembly and the right spring support assembly; the telescopic shaft penetrates through the return cylinder and the telescopic cylinder and can perform reciprocating telescopic motion relative to the return cylinder and the telescopic cylinder in a non-locking state; one end of the telescopic shaft is pressed into the pin shaft along the radial direction through interference fit, and the other end of the telescopic shaft is screwed into the left support fixing nut and the ball pin assembly; one end of the unlocking oil cylinder is connected with the upper bracket of the unlocking oil cylinder in a pin shaft and joint bearing mode, and the other end of the unlocking oil cylinder is connected with the mechanical lock assembly in a pin shaft and joint bearing mode; the upper support and the lower support of the unlocking cylinder are clamped and fixed in a clamping groove at the outer side of the return cylinder through 4 bolts; the unlocking spring support is fixed at the upper end of the telescopic cylinder through a bolt; the device adopts two unlocking springs, one end of each unlocking spring is hung on a pin shaft connected with the mechanical lock assembly and the unlocking oil cylinder, and the other end of each unlocking spring is hung on a pin shaft of the spring support. The mechanical lock assembly is fixed on the telescopic cylinder through the rotating pin shafts on the two sides, and the mechanical lock can rotate up and down around the rotating pin shafts on the two sides to unlock and lock the telescopic shaft; the check ring between the return cylinder and the cylinder body is connected with the telescopic cylinder through 8 evenly distributed bolts; the unlocking sensor support is fixed on the flange surface of the return cylinder through threaded connection, the unlocking sensor is fixed on the unlocking sensor support through threaded connection, and the locking sensor is fixed on the mechanical lock assembly through threaded connection.
Preferably, the rear axle steering pump assembly comprises a motor and a rear axle steering pump, and the rear axle steering pump assembly is provided with an oil inlet and an oil outlet; the oil outlet is connected with a first port P of the rear axle steering integrated valve group through a high-pressure oil pipe; the oil inlet is connected with a second interface T port of the rear axle steering integrated valve group through a low-pressure oil pipe; is fixed on the vehicle body auxiliary seat through bolt connection.
When a driver rotates a steering wheel, the controller reads signals of a steering wheel angle sensor to calculate the target position of the rear axle steering hydraulic cylinder, controls the valve core opening of the three-position four-way proportional valve in a current control mode, finally realizes that the steering hydraulic cylinder stretches to an absolute target position, and finally drives the rear axle steering rod system to realize the same-direction and reverse-direction rotation of the front axle.
The controller estimates the value of the steering angle of the front axle wheels according to the value collected by the steering wheel angle sensor by combining the transmission ratio of a front axle hydraulic steering gear and the angular transmission ratio of a front axle steering rod system, then determines the value of the steering angle of the rear axle wheels according to the same-direction or reverse mode by combining the corresponding same-direction coefficient and reverse coefficient, obtains the target angle of the left swing arm by combining the angular transmission ratio of the rear axle steering rod system, and obtains the piston telescopic target displacement value of the rear axle steering hydraulic cylinder by calculating the arm length of the rear axle steering hydraulic cylinder installed on the left swing arm.
The control method is as follows:
Figure BDA0002610057600000051
wherein: thetaswIs the steering wheel rotation angle (DEG), is the acquisition value of a rotation angle sensor, and ranges from-900 DEG to 900 DEG;
l is a vehicle wheel base (mm) and belongs to the overall vehicle arrangement parameter range (2800-3200);
Lgpiston telescopic target position of rear axle steering hydraulic cylinderShifting values; calculating an output value for the system;
Lggthe distance (mm) from a center hole of a left swing arm in a rear axle steering linkage to the axis of a ball pin for mounting a rear axle steering hydraulic cylinder is within the range (180-280);
ifthe angular transmission ratio of the front axle steering rod system is 0.8-1.3;
iRthe angular transmission ratio of the rear axle steering rod system is 0.8-1.3;
iTthe steering coefficient of the front axle and the rear axle in the same direction ranges from 0.2 to 0.8;
iqis the transmission ratio of the hydraulic power-assisted steering gear and is a constant;
and lambda is the equivalent wheelbase coefficient of the front axle from the instant center of turning.
Compared with the prior art, the invention has the following advantages:
1) a rear axle steering integrated valve group structure is developed. The valve bank has the advantages of reasonable structural layout, easiness in processing, small occupied space, more reasonable oil circuit, small pressure loss, convenience in pipe arrangement and convenience in adjusting and operating of each control valve. The opening of the valve core can be accurately controlled by additionally arranging the three-position four-way proportional valve, so that the expansion of the rear axle steering hydraulic cylinder along with the target displacement is accurately controlled, and the closed-loop control of the steering hydraulic cylinder and the steering wheel operation is realized.
2) A brand-new electromechanical hydraulic steering system is developed, the all-wheel steering system with the structure can be conveniently switched among three modes, and has the advantages of realizing closed-loop control of steering hydraulic cylinders and steering wheel operation and release and locking control of a steering axle passive active return and rigid locking device, and in addition, the hydraulic pressure sources of the front axle and the rear axle are independent, and the system is safe and reliable.
3) A brand-new steering return locking mechanism assembly is developed, and the follow-up extension with a rear axle steering hydraulic cylinder can be completed when the rear axle is normally steered; when the rear axle does not steer, the mechanical holding and rigid locking of the rear axle steering rod system at the middle position can be kept; when an electric or hydraulic fault occurs in the all-wheel steering system, passive active return can be realized, rigid locking can be completed, and the reliability of the whole set of all-wheel steering device is greatly improved.
4) A completely new all-wheel steering controller assembly was developed. The switching among the three modes is conveniently carried out, a plurality of fault modes are considered, and the reliability of the system under various fault modes is ensured. By adding the innovative intelligent target displacement function, the closed-loop control of the steering hydraulic cylinder and the steering wheel can be accurately realized, and the control is accurate.
5) A brand new control relation is developed, through the control relation of two working modes of 'front and rear axle steering in the same direction' and 'front and rear axle reverse steering', a controller estimates the value of the steering angle of wheels of a front axle according to the value collected by a steering wheel angle sensor by combining the transmission ratio of a front axle hydraulic steering gear and the angular transmission ratio of a front axle steering rod system, then determines the value of the steering angle of wheels of a rear axle according to the same direction or reverse mode by combining the corresponding same direction coefficient and reverse coefficient, and then obtains the target steering angle of a left swing arm 70 by combining the angular transmission ratio of the rear axle steering rod system, and the piston telescopic target displacement value of the rear axle steering hydraulic cylinder 6 is obtained by calculating the arm length of the rear axle steering hydraulic cylinder 6 installed on the left swing arm. By adding the innovative intelligent target displacement function, the closed-loop control of the steering hydraulic cylinder and the steering wheel can be accurately realized, and the control is accurate. The system has safe and reliable performance, greatly improves the safety and stability of the system, and has stable and reliable system design.
Drawings
FIG. 1 is a structural diagram of a high-reliability electro-hydraulic all-wheel steering system
FIG. 2 shows a structure of a steering wheel and power steering assembly
Fig. 2-1 combined switch structure diagram
Fig. 2-2 combined switch support structure diagram
Fig. 2-3 structure diagram of transmission shaft assembly 1
Fig. 2-4 structure diagram of front axle steering pump
Fig. 2-5 structure diagram of front axle steering oil tank
Fig. 2-6 shows the front axle steering tank clamp
FIG. 3 is a front view of a rear axle steering manifold
FIG. 4 structure diagram of rear axle steering hydraulic cylinder
FIG. 4-1 top view of the rear axle steering cylinder
FIG. 5 structure diagram of middle position locking mechanism of rear axle
FIG. 5-1 is a cross-sectional view of a rear axle neutral locking mechanism
FIG. 6 structure diagram of rear axle steering pump assembly
FIG. 6-1 rear axle steering pump assembly Structure FIG. 2
FIG. 7 structure diagram of rear axle steering oil tank assembly
FIG. 7-1 shows a front axle steering tank clip
FIG. 8 is a schematic diagram of the operation of the hydraulic system
Fig. 9 is a schematic diagram of equivalent wheelbase coefficients.
The reference numbers are as follows:
a high reliability machine-electricity-liquid all-wheel steering system structure chart: 1 steering wheel and steering gear assembly; 2, a front axle steering oil tank assembly; 3 front axle steering pump; 4, a rear axle steering oil tank assembly; 5 front axle steering linkage; 6, a rear axle steering hydraulic cylinder assembly; 7, steering and returning to the locking mechanism assembly; 8, a rear axle steering integrated valve group; 9 an all-wheel steering controller assembly; 10 rear axle steering linkage; 11 rear axle electric steering pump assembly; 70 left swing arm; 71 a right swing arm; 72 a steering rocker arm;
steering wheel and power steering assembly structure: 12 a steering wheel; 19 a first steering gear shaft; 14 a second steering drive shaft; 13 a steering wheel angle sensor; 15-degree transmission case; 16 an intermediate drive shaft assembly; 17 a hydraulic power steering assembly;
a combination switch: 80 left handle, 82 fixing hole, 81 right handle;
the combined switch bracket: 83 screw through hole, 19 steering transmission shaft;
general structure diagram of steering drive shaft: 84 combined switch bracket, 85 adjusting mechanism and 86 mounting hole;
front axle steering pump structure diagram: 301 oil inlet, 302 oil outlet, 303 steering pump mounting hole and 304 steering pump spline shaft;
front axle steering oil tank structure diagram: 203 steering oil tanks; 204 an oil tank support; 201 oil outlet, 202 oil return port;
front axle steering tank clamp: 205 front axle steering tank mounts; 206, a clamp;
the rear axle turns to the integrated valves front view: 24 a valve body; 25 three-position four-way proportional reversing valve; 26 two balancing valves; four two-position two-way solenoid valves (27,28, 30, 31); 29 two-position three-way electromagnetic valve; 32 a one-way valve; oil ports 8-P, 8-T, 8-P2, 8-T2, 8-A and 8-B;
rear axle steering hydraulic cylinder structure diagram: 88 cylinder barrels, 87 piston rods, 36 ball pins, 90 hoops, 89 clamping grooves, 35 oil cylinder displacement sensors, 34 first interfaces and 33 second interfaces;
top view of the rear axle steering hydraulic cylinder: 37 knuckle bearings;
rear axle meso position locking mechanical system: 44 unlocking oil cylinders, 52 unlocking springs, 56 returning springs, 48 mechanical lock assemblies, 60 rotating pin shafts, 45 returning cylinders, 49 telescopic cylinders, 40 telescopic shafts, 41 left support fixing nuts, 55 left spring support assemblies, 57 right spring support assemblies, 47 check rings between cylinder bodies, 50 pin shafts, 54 unlocking spring supports, 43 unlocking cylinder upper supports, 42 unlocking cylinder lower supports, 38 ball pins, 46 locking sensors, 51 unlocking sensors, 58 unlocking oil cylinder second interfaces and 59 unlocking oil cylinder first interfaces;
rear axle steering pump assembly structure diagram: 110 oil outlet, 112 mounting hole;
rear axle steering pump assembly structure 2: 111 oil inlet, 112 mounting hole;
rear axle steering oil tank assembly structure chart: 403 steering oil tanks; 404 an oil tank support; 401 oil outlet, 402 oil return port;
front axle steering tank clamp: 405 a rear axle steering tank bracket; 406 clip.
Detailed Description
The following detailed description of embodiments of the invention refers to the accompanying drawings.
In this document, "/" denotes division and "×", "denotes multiplication, referring to formulas, if not specifically stated.
In order to solve the problems in the prior art, the invention provides a high-reliability electro-hydraulic all-wheel steering system and a rear axle self-aligning and locking device thereof, in particular to a 4X4 electro-hydraulic all-wheel steering system. The front axle of the all-wheel steering device of the system adopts a hydraulic power-assisted mechanical steering mode, and the rear axle adopts an electric control hydraulic cylinder to drive the rear axle to steer. Preferably, the high-reliability 4X4 electromechanical liquid all-wheel steering system and the rear axle self-aligning and locking device thereof are suitable for wheeled vehicles with the weight of more than 5 tons.
The system and its rear axle self-aligning and locking device will be described in detail below with reference to the accompanying drawings.
As shown in fig. 1, the electromechanical hydraulic all-wheel steering system includes a steering wheel and steering gear assembly 1, a front axle steering oil tank assembly 2, a front axle steering pump 3, a rear axle steering oil tank assembly 4, a front axle steering rod system 5, a rear axle steering hydraulic cylinder assembly 6, a steering return locking mechanism assembly 7, a rear axle steering integrated valve group 8, an all-wheel steering controller assembly 9, a rear axle steering rod system 10, and a rear axle electric steering pump assembly 11. The steering wheel and steering gear assembly 1 is connected with a front axle steering rod system 5; the front axle steering pump 3 is arranged on an engine and is driven by the engine to provide a power source, preferably a high-pressure power source, for the system; an oil outlet 19 of the front axle steering oil tank assembly 2 is connected with an oil inlet end 22 of the front axle steering pump 3 through an oil pipe, and an oil return port 20 is connected with an oil return port of a steering wheel and a power steering gear assembly 17 in the power steering gear assembly 1 through an oil pipe.
An oil outlet 402 of the rear axle steering oil tank assembly 4 is connected with an oil inlet end 111 of the rear axle electric steering pump assembly 11 through an oil pipe, and an oil return port 401 is connected with an oil return port T of the rear axle steering integrated valve group 8 through an oil pipe; an oil outlet 110 of the rear axle electric steering pump assembly 11 is connected with an oil inlet end 8-P of the rear axle steering integrated valve group 8 through an oil pipe; a first interface 34 of the rear axle steering hydraulic cylinder assembly 6 is connected with an A port 8-A port of the rear axle steering integrated valve group 8 through an oil pipe, a second interface 33 of the rear axle steering hydraulic cylinder assembly 6 is connected with a B port 8-B port of the rear axle steering integrated valve group 8 through an oil pipe, and the rear axle steering hydraulic cylinder assembly 6 is connected with a left swing arm 70 of the rear axle steering rod system 10, preferably through a ball pin 36; the first connector 59 (oil inlet) of the unlocking oil cylinder 44 of the steering return locking mechanism assembly 7 is connected with the P2 port 8-P2 of the rear axle steering integrated valve group 8 through an oil pipe, the second connector 58 (oil outlet) of the unlocking oil cylinder 44 of the steering return locking mechanism assembly 7 is connected with the T2 port 8-T2 of the rear axle steering integrated valve group 8 through an oil pipe, and the steering return locking mechanism assembly 7 is connected with the right swing arm 71 of the rear axle steering rod system 10, preferably through a ball stud 38.
Through the scheme, the front axle steering system and the rear axle steering system are mechanically installed to be relatively independent, and adopt independent hydraulic sources, and the rear axle steering valve group is controlled through the all-wheel steering controller 9 to realize three steering modes of the front axle and the rear axle.
Preferably, the steering wheel and steering gear assembly 1 is located in a vehicle cabin and is fixed to a mounting bracket at an instrument panel in the cabin through four oblong holes in the angle adjusting mechanism 20.
Preferably, the power steering assembly 17 of the steering wheel and steering assembly 1 is connected to the pitman arm 72 of the front axle steering linkage 5 by a taper spline.
FIG. 2 illustrates a steering wheel and steering gear assembly of the present invention. As shown in fig. 2, the steering wheel and steering gear assembly 1 includes a steering wheel 12, a combination switch 18, a first steering transmission shaft 19, a second steering transmission shaft 14, a steering wheel angle sensor 13, an angle transmission case 15, an intermediate transmission shaft assembly 16, and a hydraulic power steering gear assembly 17. The steering wheel 12 is connected with a first steering transmission shaft 19, a combined switch bracket is processed in the middle of the first steering transmission shaft 19 and used for installing a combined switch, and the radial installation of the transmission shaft is optimized so that the combined switch 18 and the first steering transmission shaft 19 can be coaxially installed and fixed conveniently; the steering wheel angle sensor 13 is mounted on the first steering transmission shaft 19 through interference fit; preferably below the first steering shaft 19 combination switch bracket; the first steering transmission shaft 19 is connected with the second steering transmission shaft 14, and preferably, a spline shaft is processed at the bottom of the first steering transmission shaft 19 and connected with the second steering transmission shaft 14; one end of the first steering transmission shaft 19 is connected with the steering wheel 12, preferably in spline fit through a universal joint, and the other end is connected with the second steering transmission shaft 14, preferably in spline fit through a universal joint; one end of the second steering transmission shaft 14 is connected with the steering transmission shaft assembly 19, preferably in spline fit connection through a universal joint, and the other end of the second steering transmission shaft is connected with the angle transmission case 15, preferably in spline fit connection through a universal joint; one end of the intermediate transmission shaft assembly 16 is connected with the angle transmission case 15 through universal joint spline fit, and the other end is connected with an input shaft of the hydraulic power steering gear assembly 17 through universal joint spline fit. Thus, when the driver operates the steering wheel 12, the first steering transmission shaft 19, the second steering transmission shaft 14, the steering wheel angle sensor 13, the angle transmission case 15, and the external spline output end of the hydraulic power steering assembly 17 are driven to rotate coaxially therewith, and the steering wheel angle sensor 14 transmits a steering wheel angle signal to the all-wheel steering controller assembly 9.
Preferably, an inner spline hole is processed in the center of the steering wheel 12, a spline shaft is processed at the top end of the first steering transmission shaft 19, the spline shaft is inserted into the inner spline hole in the center of the steering wheel 12 and is locked through a nut, and the connection between the steering wheel 11 and the first steering transmission shaft 19 is completed;
preferably, four oblong holes are formed in the mechanism 20 for securing the steering wheel and power steering assembly 1 to the dashboard.
Preferably, an angle drive box 15 is installed between the second steering drive shaft 14 and the power steering gear 17, and the function is to ensure the flexibility of the installation arrangement of the steering wheel 12 and the power steering gear 17 in a real vehicle.
The hydraulic power steering gear assembly 17 is provided with two oil way interfaces of an oil inlet P and an oil return port T, and is respectively connected with an oil outlet port 302 of the front axle steering pump 3 and an oil return port 201 of the front axle steering oil tank assembly 2;
preferably, the front axle steering pump 3 is mounted on the engine, as shown in fig. 2-4, the front axle steering pump 3 has two oil port interfaces, a first interface 301 is connected with the oil outlet 202 of the front axle steering oil tank assembly 2, and a second interface 302 is connected with the oil inlet P of the hydraulic power steering gear assembly 17, and the function of the front axle steering pump is to provide a hydraulic power source for the front axle steering system;
as shown in fig. 2-5, the front axle steering oil tank assembly 2 includes a steering oil tank 203 and an oil tank support 204, the steering oil tank 203 is fixed on the vehicle body through the oil tank support 205, and has two oil line interfaces, which are respectively an oil outlet 202 and an oil return port 201, the oil outlet 202 is connected with an oil inlet 301 of the steering pump 3, the oil return port 201 is connected with an oil return port T of the hydraulic power steering gear assembly 1 and a 2 nd interface 8-T of the rear axle steering integrated valve group 8, and the function of the front axle steering oil tank assembly is to provide a hydraulic source for the front axle steering system.
As shown in fig. 3, the rear axle steering integrated valve group 8 includes a valve body 24, a three-position four-way proportional directional valve 25, two balance valves 26, four two-position two- way solenoid valves 27,28, 30 and 31, a two-position three-way solenoid valve 29 and a check valve 32. The rear axle steering integrated valve group 8 is fixed on a vehicle body bottom plate through a through hole on the valve body 24, and is provided with 6 oil way interfaces, and the interfaces are preferably ferrule type straight joint structures.
Preferably, the valve body 24 is a cubic structure, which includes six faces, the two balance valves 26, the four two-position two- way solenoid valve 27,28, 30 and 31, the two-position three-way solenoid valve 29 and the check valve 32 are located on a first face, the three ports 8-P2, the fourth port 8-T2, the fifth port 8-a and the sixth port 8-B are located on a second face perpendicularly connected to the first face, the first port 8-P and the second port 8-T are located on a third face connected to the first face and the second face, the fourth face is opposite to the third face, and the three-position four-way proportional directional valve 25 is located at a middle position of the fourth face.
Preferably, on the first face, the valves 27,28 and 31 are located on the side away from the second face, and the valves 31, 28 and 27 are arranged in this order from the third face to the fourth face; valves 29, 30 are provided on a side close to the second face, wherein the valves 30, 29 are arranged in order from the third face to the fourth face, and the valves 30, 29 are arranged close to the side of the third face; a one-way valve 32 is located between the valves 30, 31; two balancing valves 26 are located at positions between the valve 29 and the fourth face and between the valves 27,28 and the second face.
On the second surface, the interfaces 8-P2 and 8-T2 are arranged on the side close to the first surface, preferably on the side close to the third surface, wherein the interfaces 8-P2 and 8-T2 are arranged in sequence from the third surface to the fourth surface; the ports 8-A, 8-B are arranged on the side remote from the first face, preferably on the side close to the fourth face, from which the ports 8-B, 8-A are arranged in order from the third face to the fourth face.
On the third face, the first interface 8-P and the second interface 8-T are arranged close to the first face, wherein the first interface 8-P is further away from the second face than the second interface 8-T.
Through the above structural layout, the rear axle steering integrated valve group 8 can be more reasonably arranged, is easy to process, occupies small space, has more reasonable oil way, small pressure loss, convenient pipe distribution and convenient adjustment and operation of each control valve. The rear axle steering integrated valve group structure of fig. 3 has the advantages of reasonable valve group structural layout, easy processing, small occupied space, more reasonable oil circuit, small pressure loss, convenient pipe distribution and convenient adjustment and operation of each control valve. The opening of the valve core can be accurately controlled by additionally arranging the three-position four-way proportional valve, so that the expansion of the rear axle steering hydraulic cylinder along with the target displacement is accurately controlled, and the closed-loop control of the steering hydraulic cylinder and the steering wheel operation is realized.
The first interface is an oil inlet port 8-P which is connected with an oil outlet 110 of the rear axle steering pump assembly 11, and the second interface is an oil return port 8-T which is connected with an oil return port 401 of the rear axle steering oil tank assembly 4; the third port 8-P2 and the fourth port 8-T2 are respectively connected with the first port 59 and the second port 58 of the unlocking oil cylinder 44 of the steering return locking mechanism assembly 7; the fifth interface 8-A and the sixth interface 8-B are connected with a first interface 34 and a second interface 33 of the rear axle steering hydraulic cylinder assembly 6.
The rear axle steering integrated valve group 8 has the functions that: according to a steering mode selected by a driver, receiving a switching value signal provided by an all-wheel steering controller, and simultaneously controlling four two-position two-way electromagnetic valve 27, a valve 28, a valve 30, a valve 31 and a two-position three-way electromagnetic valve 29 to switch oil ways, so that steering in three modes, namely front axle steering, front and rear axle same-direction steering and front and rear axle reverse steering, is realized according to the steering mode required by the driver; the rear axle steering integrated valve group 8 receives a current signal provided by the all-wheel steering controller, controls the opening of the valve body of the three-position four-way proportional reversing valve 25, and realizes the stable following of the rear axle steering rod system to the front axle steering. Specifically, the method comprises the following steps: the two-position two-way electromagnetic valves 27 and 28 are respectively connected in series between the port A, namely the port 8-A, B, namely the port 8-B, and the port T, namely the port 8-T, after the power-on is switched on, the two cavities of the rear axle steering oil cylinder are communicated and are in an unloading state; after the electromagnetic valve is powered off, the rear axle steering oil cylinder can build pressure, and the controller controls the extension and retraction of a piston rod of the rear axle steering oil cylinder 6 by controlling the power supply current of the three-position four-way proportional reversing valve 25; the two balance valves 26 are respectively connected in series between the three-position four-way proportional reversing valve 25 and the ports 8-A, B A and 8-B, so that the pressure maintaining effect on the pressure of the two cavities of the rear axle steering hydraulic cylinder 6 can be realized, and the stable state of each position in the steering process can be ensured; the two-position two-way electromagnetic valve 30 and the two-position three-way electromagnetic valve 29 are connected in series between the port 8-T of the port P8-P, T and the port 8-P2 of the port P2, and the power supply of the two-position two-way electromagnetic valve 30 and the two-position three-way electromagnetic valve 29 is controlled by the controller to realize the oil charging and discharging of the rod cavity of the unlocking oil cylinder 44; the T2 port 8-T2 is communicated with the T port 8-T and returns to the rear axle steering oil tank assembly 4 in a unified way.
The rear axle steering integrated valve group 8 is an invention point of the invention, and the invention can realize the oil circuit switching among three steering modes of front axle steering, front and rear axle same-direction steering and front and rear axle reverse steering of the rear axle according to the requirements of a driver.
As shown in fig. 4, the rear axle steering hydraulic cylinder 6 comprises a cylinder barrel 88, a piston rod 87, a ball stud 36, a clamp 90 and a cylinder displacement sensor 35, and the rear axle steering hydraulic cylinder is provided with a first connector 34 and a second connector 33 which are respectively connected with a fifth connector 8-a and a sixth connector 8-B of the rear axle steering integrated valve group 8 through high-pressure oil pipes; the oil cylinder displacement sensor 35 is arranged inside the cylinder barrel; the output end of the piston rod is of an internal thread tubular structure, a groove is processed on the side face of the output end of the piston rod, and the ball heads are respectively screwed at the output end of the piston rod and locked by a clamp at the groove to fix the screwing depth of the ball heads. The fixed end of the cylinder barrel is processed into an annular groove, a joint bearing is pressed in, and the cylinder barrel is fixed at the auxiliary seat of the rear axle steering hydraulic cylinder through a pin shaft. One end of the rear axle steering hydraulic cylinder assembly 6 is connected with the vehicle body auxiliary seat through a joint bearing, the other end of the rear axle steering hydraulic cylinder assembly 6 is connected with the left swing arm 70 of the rear axle steering rod system 10 through a ball pin 36, so that the rear axle steering hydraulic cylinder assembly 6 is fixed, the first connector 34 of the upper oil way of the rear axle steering hydraulic cylinder assembly 6 is connected with the fifth connector 8-A of the rear axle steering integrated valve group 8, and the second connector 33 is connected with the sixth connector 8-B of the rear axle steering integrated valve group 8.
Fig. 5 shows a schematic structural diagram of the steering return locking mechanism assembly 7. As shown in fig. 5, the steering return locking mechanism assembly 7 includes an unlocking cylinder 44, an unlocking spring 52, a return spring 56, a mechanical lock assembly 48, a rotating pin 60, a return cylinder 45, a telescopic cylinder 49, a telescopic shaft 40, a left support fixing nut 41, a left spring support assembly 55, a right spring support assembly 57, an inter-cylinder retainer ring 47, a pin 50, an unlocking spring support 54, an unlocking cylinder upper bracket 43, an unlocking cylinder lower bracket 42, a ball stud 38, a locking sensor 46, and an unlocking sensor 51. The return spring 56 is arranged in the return cylinder body 45, the left end and the right end of the return cylinder 45 are respectively connected with the unlocking cylinder support and the telescopic cylinder 49, the unlocking cylinder support comprises an unlocking cylinder upper support 43 and an unlocking cylinder lower support 42, the upper end of the unlocking cylinder upper support 43 is connected with one end of the unlocking oil cylinder 44, the other end of the unlocking oil cylinder 44 is connected with a pin shaft, and the pin shaft is a pin shaft for connecting the mechanical lock assembly 48 and the unlocking oil cylinder 44; one end of the unlocking spring 52 is hung on a pin shaft connected with the mechanical lock assembly 48 and the unlocking oil cylinder 44, the other end of the unlocking spring is hung on a pin shaft of the unlocking spring support 54, and the unlocking spring support 54 is fixed at the upper end of the telescopic cylinder 49; one end of the mechanical lock assembly 48 is fixed on the telescopic cylinder 49; the telescopic shaft 40 extends into the return cylinder 45 and the telescopic cylinder 49.
The left end and the right end of the return spring 56 are arranged in the return cylinder body 45 through a left spring support assembly 55 and a right spring support assembly 57, and the return spring 56 is respectively compressed leftwards and rightwards by pushing the left spring support assembly 55 and the right spring support assembly 57; the telescopic shaft 40 penetrates through the return cylinder 45 and the telescopic cylinder 49 and can perform reciprocating telescopic motion relative to the return cylinder 45 and the telescopic cylinder 49 under the condition of no locking; one end of the telescopic shaft 40 is pressed into the pin shaft 50 along the radial direction through interference fit, and the other end is screwed into the left support fixing nut 41 and the ball stud 38; one end of the unlocking oil cylinder is connected with the unlocking cylinder upper bracket 43 in a pin shaft and joint bearing mode, and the other end of the unlocking oil cylinder is connected with the mechanical lock assembly 48 in a pin shaft and joint bearing mode; the unlocking cylinder upper support 43 and the unlocking cylinder lower support 42 are clamped and fixed in a clamping groove on the outer side of the return cylinder 45 through 4 bolts; the unlocking spring support 54 is fixed at the upper end of the telescopic cylinder 49 through a bolt; the device adopts two unlocking springs 52, one end of each unlocking spring 52 is hung on a pin shaft connected with the mechanical lock assembly 48 and the unlocking oil cylinder 44, and the other end of each unlocking spring 52 is hung on a pin shaft of the spring support 54. The mechanical lock assembly 48 is fixed on the telescopic cylinder 49 through the rotating pin shafts 60 on the two sides, and the mechanical lock can rotate up and down around the rotating pin shafts 60 on the two sides to unlock and lock the telescopic shaft 40; the return cylinder 45, the check ring 47 between the cylinder bodies and the telescopic cylinder 49 are connected through 8 evenly distributed bolts; the unlocking sensor support 61 is fixed on the flange surface of the return cylinder 45 through threaded connection, the unlocking sensor 46 is fixed on the unlocking sensor support 61 through threaded connection, and the locking sensor 51 is fixed on the mechanical lock assembly 48 through threaded connection.
When the front axle is steered, the steering return locking mechanism assembly 7 is in a neutral and locked state. At this time, the return spring 56 drives the left spring support assembly 55 and the right spring support assembly 57 to respectively contact with the inner side of the return cylinder 45 and the retainer ring 47 between the cylinder bodies, so as to drive the telescopic shaft 40 to return to an initial middle position state, after the return spring 56 returns to the middle position, the oil ports 8-a and 8-B of the hydraulic valve bank are controlled, the unloading of the unlocking oil cylinder 44 is in a free state, the two unlocking springs 52 drive the mechanical lock assembly 48 to rotate downwards around the mechanical lock rotating pin shaft 60, the semicircular clamping grooves of the mechanical lock assembly 48 are clamped into the pin shaft 50, and the telescopic shaft 40 cannot perform telescopic motion.
When the rear axle participates in steering, the steering return locking mechanism assembly 7 is in an unlocking follow-up state. At this time, the first interface 59 of the unlocking oil cylinder 44 is filled with oil, the piston rod of the unlocking oil cylinder 44 contracts to drive the mechanical lock assembly 48 to rotate upwards around the mechanical lock rotating shaft 60, and the mechanical lock assembly 48 is unlocked in place until the signal lamp of the unlocking sensor 46 is on; at this point, the telescopic shaft 40 may then undergo a reciprocating telescopic motion as required by the movement of the axle steering linkage: when the telescopic shaft 40 contracts, the nut 41 pushes the left spring support assembly 55 to move rightwards along with the telescopic shaft 40, the right spring support assembly 57 is tightly attached to the retainer ring 47 between the cylinder bodies, and the compression of the telescopic shaft 40 is realized by compressing the return spring 56 rightwards; when the telescopic shaft 40 extends, the shaft space of the telescopic shaft 40 is attached to the right spring support assembly 57 and moves leftwards, the left spring support assembly 55 is attached to the inner surface of the return cylinder 45, and the telescopic shaft 40 extends by compressing the return spring leftwards.
One end of the steering return locking mechanism assembly 7 is connected with the vehicle body auxiliary seat through a joint bearing, the other end of the steering return locking mechanism assembly 7 is connected with the right swing arm 71 of the rear axle steering rod system 10 through a ball stud 38, so that the steering return locking mechanism assembly 7 is fixed, and the first connector 59 and the second connector 58 of the oil way of the unlocking oil cylinder 44 are connected with the third connector 8-P2 and the fourth connector 8-T2 of the rear axle steering integrated valve group 8.
The steering return lock mechanism assembly of fig. 5. The servo-actuated telescopic device can complete the follow-up telescopic with the rear axle steering hydraulic cylinder when the rear axle normally steers; when the rear axle does not steer, the mechanical holding and rigid locking of the rear axle steering rod system at the middle position can be kept; when an electric or hydraulic fault occurs in the all-wheel steering system, passive active return can be realized, rigid locking can be completed, and the reliability of the whole set of all-wheel steering device is greatly improved.
The all-wheel steering mode change-over switch is integrated in the control panel of the whole vehicle, is operated by a driver and has three working modes of front axle steering, front and rear axle equidirectional steering and front and rear axle reverse steering. As shown in fig. 1 to 7, the operating principle of a highly reliable electro-hydraulic all-wheel steering apparatus according to the present invention is characterized as follows:
front axle steering mode
When the front axle steering mode is adopted, the all-wheel steering mode change-over switch is in a front axle steering state, a driver rotates a steering wheel, a corner signal of the steering wheel is sent to a steering controller, a control system controls the two-position two-way electromagnetic valve 31 to be powered off according to a front axle steering control strategy, and simultaneously controls the oil passages of a first port P8-P and a second port T8-T in the rear axle steering integrated valve group 8 to be unblocked, so that the aim is to unload the unlocking oil cylinder 44, drive the mechanical lock 48 to complete the lock-down by the unlocking spring 52, and be in a locked state, and ensure that the rear axle is positioned in a middle position and does not participate in steering.
(II) "same direction steering of front and rear axles" mode
In the mode of 'same-direction steering of front and rear axles', oil passages of a first port 8-P and a third port 8-P2 in the rear axle steering integrated valve group 8 are smooth, and oil passages of a second port 8-T and a fourth port 8-T2 are smooth, so that oil is filled into a rod cavity of the unlocking oil cylinder 44, the mechanical lock 48 is driven to rotate upwards around the rotating shaft, and unlocking is completed; the controller controls the two-position two-way electromagnetic valve 27 and the valve 28 to be electrified to realize the pressure build-up of the rear axle steering hydraulic cylinder 6, when a driver rotates a steering wheel, the steering wheel corner sensor 13 sends a steering wheel corner signal to the steering controller 9, the control system calculates the target displacement of the rear axle steering hydraulic cylinder 6 according to the control strategy of front and rear axle same-direction steering, the displacement stroke of the rear axle steering hydraulic cylinder 6 is accurately realized through the current control of the three-position four-way proportional reversing valve 25, the left steering rocker arm 70 is pushed to rotate through the ball pin 36, and the rear axle steering rod system is driven to realize the same-direction steering of the rear axle along with the front axle;
(III) front and rear axle reverse steering mode
In the mode of 'reverse steering of front and rear axles', oil passages of a first port 8-P and a third port 8-P2 in the rear axle steering integrated valve group 8 are smooth, and oil passages of a second port 8-T and a fourth port 8-T2 are smooth, so that oil is filled into a rod cavity of the unlocking oil cylinder 44, the mechanical lock 48 is driven to rotate upwards around the rotating shaft, and unlocking is completed; the controller controls the two-position two-way electromagnetic valve 27 and the valve 28 to be electrified to realize the pressure build-up of the rear axle steering hydraulic cylinder 6, when a driver rotates a steering wheel, the steering wheel corner sensor 13 sends a steering wheel corner signal to the steering controller 9, the control system calculates the target displacement of the rear axle steering hydraulic cylinder 6 according to the control strategy of the front axle and the rear axle reverse steering, the displacement stroke of the rear axle steering hydraulic cylinder 6 is accurately realized through the current control of the three-position four-way proportional reversing valve 25, and the left steering rocker arm 70 is pushed to rotate through the ball head pin 36 to drive the rear axle steering rod system to realize the reverse steering of the rear axle along with the front axle.
Referring to fig. 6, the rear axle steering pump assembly 11 includes a motor and a rear axle steering pump, and has an oil inlet 111 and an oil outlet 110. The oil outlet 110 is connected with a first port P8-P of the rear axle steering integrated valve group 8 through a high-pressure oil pipe; the oil inlet 111 is connected with a second port T8-T of the rear axle steering integrated valve group 8 through a low-pressure oil pipe; is fixed on the vehicle body auxiliary seat through bolt connection.
In the device, under two working modes of 'front and rear axle steering in the same direction' and 'front and rear axle steering in the reverse direction', when a driver rotates a steering wheel, a controller reads a signal of a steering wheel corner sensor 13 to calculate the target position of a rear axle steering hydraulic cylinder 6, controls the valve core opening of a three-position four-way proportional valve 25 in a current control mode, finally realizes that the steering hydraulic cylinder stretches to an absolute target position, and finally drives a rear axle steering rod system 10 to realize the same direction and reverse rotation of a front axle. In a control system, an intelligent target displacement function is innovatively provided. Specifically, the controller estimates the value of the steering angle of the front axle wheels according to the value collected by the steering wheel angle sensor by combining the transmission ratio of a front axle hydraulic steering device and the angular transmission ratio of a front axle steering rod system, then determines the value of the steering angle of the rear axle wheels according to the same-direction or reverse mode by combining the corresponding same-direction coefficient and reverse coefficient, obtains the target angle of the left swing arm 70 by combining the angular transmission ratio of the rear axle steering rod system, and obtains the piston telescopic target displacement value of the rear axle steering hydraulic cylinder 6 by calculating the arm length of the rear axle steering hydraulic cylinder 6 installed on the left swing arm. The basic method is as follows:
Figure BDA0002610057600000141
wherein: thetaswThe steering wheel rotation angle (DEG) is the collected value of a rotation angle sensor, and the preferred range is-900 DEG;
l is a vehicle wheel base (mm), belongs to vehicle overall arrangement parameters and is in an optimal range (2800-3200);
Lgis the piston extension target displacement value of the rear axle steering hydraulic cylinder 6; calculating an output value for the system;
Lggthe distance (mm) from the center hole of the left swing arm 70 in the rear axle steering linkage to the axis of the ball pin 36 for mounting the rear axle steering hydraulic cylinder 6 is within the preferable range (180-280);
ifthe angle transmission ratio of the front axle steering rod system is preferably 0.8-1.3;
iRthe preferred range of the angular transmission ratio of the rear axle steering rod system is 0.8-1.3;
iTthe optimal range is 0.2-0.8 for the co-steering coefficient of the front and rear axles;
iqis the transmission ratio of the hydraulic power steering gear and is constant. Preferably 26;
and lambda is an equivalent wheelbase coefficient of the front axle distance steering instant center, and is obtained through calculation, preferably 0.6-0.8. The "wheelbase" of an all-wheel-steering vehicle is different from a front axle-steering vehicle in that the distance between two axles is not simply the longitudinal distance from the axle to the instant center of steering. A virtual rear axle is established for an all-wheel steering vehicle, the virtual rear axle is taken as a rear axle of a front axle steering vehicle and corresponds to a non-steering rear axle of the front axle steering vehicle during analysis, and the distance from a front axle of the vehicle to a steering transient point along a longitudinal center line is an equivalent wheelbase. The ratio of the equivalent wheel base to the wheel base is an equivalent wheel base coefficient, and the determination of the parameter is closely related to the requirement of the minimum steering radius of the whole vehicle. See in particular fig. 9. In fig. 9, L is the wheel base, and λ is the equivalent wheel base coefficient of the front axle from the instant center of turning.
According to the invention, through a large amount of researches, a brand-new calculation mode of the piston telescopic target displacement value of the rear axle steering hydraulic cylinder 6 is developed, the piston telescopic target displacement value of the rear axle steering hydraulic cylinder 6 is accurately calculated, and an innovative intelligent target displacement function is added, so that the closed-loop control of the steering hydraulic cylinder and the steering wheel operation can be accurately realized, and the control is accurate; the system has safe and reliable performance, greatly improves the safety and stability of the system, has stable and reliable system design, and can ensure the safety of vehicles.
For safety, when the vehicle speed exceeds the limit, if the driver can not switch to the front axle steering mode in time, the all-wheel steering controller can automatically switch to the front axle steering mode; when the system has an electro-hydraulic fault, the rear axle steering hydraulic cylinder can unload, the rear axle passive self-aligning and locking device can drive the rear axle steering rod to be aligned to the middle position, and the mechanical lock is controlled to be locked to complete the mechanical locking of the rear axle.
As a high-reliability electromechanical liquid all-wheel steering system with steering axle passive neutral position aligning and rigid locking functions, a driver can realize the switching of three steering modes, namely a front axle steering mode, a front axle in-phase steering mode and a front axle out-phase steering mode) according to actual road conditions, and the device can simultaneously have the dynamic response and impact resistance of a follow-up steering axle in a complex environment, and has the following advantages compared with the existing all-wheel steering system, wherein the follow-up steering axle passive neutral position aligning and rigid steering system has three core capabilities of neutral steering rigidity of the follow-up steering axle under nonlinear load, system failure and active aligning of the follow-up steering axle under a vehicle damaged state:
1. the high-reliability electromechanical hydraulic all-wheel steering system has the advantages of simple structure, stable work and high reliability, the front axle and the rear axle adopt independent hydraulic sources, the steering system can realize the switching of three steering modes (a front axle steering mode, a front axle in-phase steering mode, a front axle out-phase steering mode and a rear axle out-phase steering mode) according to the requirements of a driver, and meanwhile, the switching of the safety modes can be automatically carried out according to the safety requirements of a real vehicle in the aspect of active safety.
2. The invention designs a steering return locking mechanism assembly which is a core component of the device and is a key component for ensuring the reliability and safety of an all-wheel steering vehicle. The mechanism can realize follow-up steering according to the instruction of a controller when a rear steering axle participates in steering; when the rear steering axle does not need to be steered, the rear steering axle is rotated back to the middle position in a follow-up mode according to the instruction of the controller, and mechanical locking of the rear axle is completed through a mechanical structure, so that the rear steering axle is reliable and stable; when unforeseen trouble appears in the vehicle, can drive the rear steering axle and realize passively returning to the meso position to accomplish the mechanical lock of rear axle through mechanical structure and die. The automatic passive neutral position returning and locking mechanism greatly improves the safety of the all-wheel steering vehicle, and cannot be realized by the conventional all-wheel steering system.
3. The invention designs the rear axle steering integrated valve group for the all-wheel steering system, the valve group integration level is high, the control is accurate, and the accurate steering of the rear steering axle is realized by accurately controlling the proportional valve.
It should be noted that the heavy recirculating ball type dual mode electric power steering apparatus of the present invention can be easily understood by those skilled in the art to be applied to different types of wheeled vehicle steering systems, manned and unmanned, in the above-mentioned manner, and that various modifications and changes in form can be made thereto without departing from the spirit and scope of the present invention as defined by the appended claims.
Although the present invention has been described with reference to the preferred embodiments, it is not limited thereto. Various changes and modifications may be effected therein by one skilled in the art without departing from the spirit and scope of the invention as defined in the appended claims.

Claims (2)

1. A4X 4 electromechanical liquid all-wheel steering system is characterized by comprising a steering wheel and steering gear assembly, a front axle steering oil tank assembly, a front axle steering pump, a rear axle steering oil tank assembly, a front axle steering rod system, a rear axle steering hydraulic cylinder assembly, a steering return locking mechanism assembly, a rear axle steering integrated valve set, an all-wheel steering controller assembly, a rear axle steering rod system and a rear axle electric steering pump assembly, wherein the steering wheel and steering gear assembly is connected with the front axle steering rod system; the front axle steering pump is arranged on the engine and is driven by the engine to provide a power source for the system; an oil outlet of the front axle steering oil tank assembly is connected with an oil inlet end of a front axle steering pump through an oil pipe, and an oil return port is connected with a steering wheel and an oil return port of a power steering gear assembly in the steering gear assembly through oil pipes;
an oil outlet of the rear axle steering oil tank assembly is connected with an oil inlet end of the rear axle electric steering pump assembly through an oil pipe, and an oil return port is connected with an oil return port T of the rear axle steering integrated valve group through an oil pipe; an oil outlet of the rear axle electric steering pump assembly is connected with an oil inlet end of the rear axle steering integrated valve group through an oil pipe; a first interface of a rear axle steering hydraulic cylinder assembly is connected with an A port of a rear axle steering integrated valve group through an oil pipe, a second interface of the rear axle steering hydraulic cylinder assembly is connected with a B port of the rear axle steering integrated valve group through an oil pipe, the rear axle steering hydraulic cylinder assembly is connected with a left swing arm of a rear axle steering rod system, a first interface of an unlocking oil cylinder of a steering return locking mechanism assembly is connected with a P2 port of the rear axle steering integrated valve group through an oil pipe, a second interface of the unlocking oil cylinder of the steering return locking mechanism assembly is connected with a T2 port of the rear axle steering integrated valve group through an oil pipe, and the steering return locking mechanism assembly is connected with a right swing arm of the rear axle steering rod system;
the front axle steering oil tank assembly comprises a steering oil tank and an oil tank support, wherein the steering oil tank is fixed on a vehicle body through the oil tank support and is provided with two oil way interfaces which are respectively an oil outlet and an oil return port, the oil outlet is connected with an oil inlet of a front axle steering pump, and the oil return port is connected with an oil return port T of a power steering gear assembly and a No. 2 interface of a rear axle steering integrated valve group.
2. The system of claim 1, wherein the rear axle steering integrated valve set comprises a valve body, a three-position four-way proportional reversing valve, two balancing valves, first to fourth four two-position two-way solenoid valves, a two-position three-way solenoid valve, and a one-way valve; the rear axle steering integrated valve group is provided with 6 oil way interfaces from a first interface to a sixth interface;
the valve body is of a cubic structure and comprises six faces, the two balance valves, the four two-position two-way electromagnetic valves, the two-position three-way electromagnetic valves and the one-way valve are located on the first face, the four interfaces of the third interface, the fourth interface, the fifth interface and the sixth interface are located on the second face vertically connected with the first face, the first interface and the second interface are located on the third face connected with the first face and the second face, the fourth face is opposite to the third face, and the three-position four-way proportional reversing valve is located in the middle of the fourth face.
CN202010751005.3A 2019-04-22 2019-04-22 Front axle steering oil tank assembly and steering system Active CN111845928B (en)

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CN201910321984.6A CN110282008B (en) 2019-04-22 2019-04-22 Rear axle steering integrated valve group and steering device

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CN111845928A (en) 2020-10-30

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