CN1966330A - Steering device of automobile electronic steering system - Google Patents

Abstract

The invention provides a steering gear in an automobile electronic steering system. The steering gear includes a motor, a reduction mechanism, a transmission mechanism and a bevel gear set connected in sequence. Using this kind of steering gear, the motor receives the steering signal of the car and moves, and transmits the motion to the wheels through the reduction mechanism, the transmission mechanism and the bevel gear set to make the wheels turn. Compared with the traditional steering gear, the rotation of the bevel gear set is more flexible, so the rotation of the wheel is more flexible, and the rotation can exceed 60 degrees at least, thus overcoming the disadvantage of the limited wheel angle of the traditional steering gear.

Description

Deflector in the automobile electronic steering system

Technical field

The present invention relates to automobile steering system, relate in particular to the deflector in the automobile electronic steering system.

Background technology

Automobile steering system is the mechanism that is used to change vehicle traveling direction in the automobile.According to the difference of steerable energy, automobile steering system can be divided into manual steering system power steering system two major types of unifying traditionally.

The mechanical steering system be muscle power with chaufeur as steerable energy, wherein all force transmission elements all are mechanical, are called the manual steering system again.Power steering system is to add a cover to turn to augmenter to form on the basis of mechanical steering system.

Form by three parts as manual steering system is unified, i.e. steering control mechanism, deflector and steering gear.Steering control mechanism is the mechanism of pilot control deflector work, mainly is made up of steering handwheel, steering shaft etc.Deflector is that the rotation with steering handwheel becomes the swing of pitman arm or the straight reciprocating motion of rack shaft, and the mechanism that handling maneuver power is amplified.Steering gear is that wheel is passed in the power and the motion of deflector output, and makes left and right wheels carry out the mechanism of deflection by certain relation.

The function of deflector is that the moment that chaufeur is added on the steering handwheel is amplified, and underspeeds, and passes to steering gear then.Existing deflector mainly contains pinion and-rack, recirculating ball rack tooth fan formula, recirculating ball crank stylus pin formula and worm screw crank stylus pin formula etc.Medium and small car and front axle axle load adopt rack and pinion steering gear less than passenger vehicle, the lorry of 1.2t more.

As shown in Figure 1, during motor turning, require all wheel axiss all should intersect at a point, this intersection point O is called the motor turning center.For guaranteeing that each wheel has only rolling not have sideslip, motor turning should satisfy following formula:

$\cot \mathrm{\α}-\cot \mathrm{\β}=\frac{B}{L}---\left(1\right)$

In the formula (1):

α---outer steering wheel angle;

β---interior steering wheel angle;

Distance between B---both sides main pin axis and the ground intersection point is also referred to as wheelspan;

L---vehicle wheel base.

The turn radius that is called automobile by turning center O to the distance R of outer wheel flutter and ground contact point.Turn radius is more little, and then the required place of motor turning is more little, and its manoevreability is just good more.

When outer steering wheel angle α reaches maxim α _MaxThe time, turn radius R has minimum value R _Min, the pass between them is:

$R_{\min }=\frac{L}{{\sin \mathrm{\α}}_{\max }}=\sqrt{{\left(\frac{L}{{\sin \mathrm{\β}}_{\max }}\right)}^2+B^2+\frac{2\mathrm{BL}}{{\tan \mathrm{\β}}_{\max }}}---\left(2\right)$

Because the rack stroke of car rack and pinion steering gear is limited by tooth bar length and body width, so the maximum deflection angle α of inside and outside wheel flutter _MaxOr β _MaxLimited, common β _MaxBe 35 °～40 °, so the minimum turning radius of automobile can only arrive to a certain degree for a short time, therefore the steering flexibility of this automobile is restricted.

In above-mentioned steering swivel system, the ratio of the corresponding increment of homonymy steering swivel corner (the corner increment of steering handwheel with) is fixing because the angular gear ratio that turns to, the cornering properties of automobile presents the strong nonlinearity time-varying characteristics along with car speed and lateral acceleration change, be the rail running of Control of Automobile along the chaufeur expectation, the characteristic of chaufeur adjusting constantly itself has increased the mental burden when driving.When the cornering properties of automobile changed within the specific limits, chaufeur can satisfy the road of people's truck system by the characteristic of regulating oneself and follow requirement.But under limiting condition, as braking swerve etc., because motor turning characteristic generation steep variation, as become oversteer from understeering, chaufeur may cause traffic accident thus with uncontrollable automobile.

Therefore, some electric steering systems (SBW) have been developed at present, not only can improve the force transfering characteristic of motor turning, and the angle transmission characteristic that can design vehicle turns to, bring sizable space for the design of motor turning characteristic, thereby reduce the manipulation burden of chaufeur, improve the active safety performance of people's car closed loop system.

In " Chinese mechanical engineering " the 15th volume o. 11th " vehicle front electric steering system " article in first half of the month in June, 2004, the vehicle front electric steering system is introduced.As shown in Figure 2, the vehicle front electric steering system mainly by the bearing circle module, turn to supplementary modules such as execution module and three parts of master controller (ECU) and failsafe system, power supply to form.

The bearing circle module mainly comprises bearing circle, steering wheel angle, torque sensor, bearing circle aligning torque motor.The bearing circle module functions is that the intention that turns to chaufeur converts digital signal to and passes to master controller by direction of measurement dish corner, accept the torque signals that master controller is sent here simultaneously, produce the bearing circle aligning torque, to offer the corresponding road feel information of chaufeur.

Turn to execution module to comprise the front wheel angle sensor, turn to actuating motor, electric machine controller and front-wheel steering assembly etc.The function that turns to execution module is to measure the front-wheel steering signal feedback to give master controller, and accepts the order of master controller, and the control steer motor realizes the front wheel angle of requirement, finishes the intention that turns to of chaufeur.

Master controller carries out analyzing and processing to the signal of gathering, differentiate car behaviour, return positive motor and steer motor transmission order to bearing circle, the work of two motors of control, guarantee motor turning response characteristic basically identical under the different speed of a motor vehicle as far as possible, reduce chaufeur the motor turning characteristic is changed compensating of task with the speed of a motor vehicle, alleviate the chaufeur burden.Simultaneously, controller can also be discerned the operating order of chaufeur, whether the steering operation of judgement chaufeur under current state is reasonable, when automobile is in unsteady state and chaufeur and sends false command, the front-wheel electric steering system will be stablized control or automatically with the shielding of the steering operation of chaufeur mistake, and, make automobile be returned to stabilized conditions as early as possible with the reasonable manner automatic driving vehicle.

Failsafe system is the important module of electric steering system, and it comprises series of monitoring and implement algorithm, makes corresponding processing at different failure modes and fault level, in the hope of keeping the cruising of automobile to greatest extent.As one of most widely used vehicle, the safety of automobile is the factor that must at first consider, thereby the automatic detection of fault is one of the most important composition of front-wheel electric steering system system with handling automatically.It adopts independent application specific processor, to improve vehicle safety performance better.Power-supply system is being born the power supply of controller, two execution motors and other vehicular electrical appliances.

In this electric steering system, mainly be to have cancelled the mechanical connection between the bearing circle and wheel flutter in the conventional steering system, and replace connecting, so more convenient to operate, flexible with control signal.But, in this piece article, do not mention the structure of deflector, i.e. the deflector of adopting at present is still deflectors such as pinion and-rack, recirculating ball rack tooth fan formula, recirculating ball crank stylus pin formula and worm screw crank stylus pin formula mainly.Therefore, the above-mentioned problem of mentioning still exists, and promptly because the rack stroke of car rack and pinion steering gear is limited by tooth bar length and body width, the automobile minimum turning radius can only arrive to a certain degree for a short time, and the steering flexibility of automobile is restricted.

Summary of the invention

Therefore, the purpose of this invention is to provide the deflector in a kind of automobile electronic steering system, this deflector can overcome the shortcoming that inside and outside wheel can not independent steering, make inside and outside wheel carry out independent steering according to the best angle relation that ECU calculates gained, thereby guaranteeing that wheel has only rolls and does not have sideslip, and has greatly improved the hard-over of wheel flutter.

In order to realize this purpose, the invention provides the deflector in a kind of automobile electronic steering system, this deflector comprises bonded assembly motor, speed reduction gearing, transmission device and bevel gear set successively.

Use this deflector, motor is accepted the motor turning signal and is moved, and passes motion to wheel by speed reduction gearing, transmission device and bevel gear set, makes wheel steering.Compare with traditional deflector, because rotatablely moving of bevel gear set is more flexible, institute is so that the rotation of wheel is more flexible, and rotation can surpass 60 degree at least, thereby has overcome the limited shortcoming of wheel steering angle of use conventional steering device.

When automobile was the four-wheel individual drive, this deflector can make automobile make four wheel steerings when the original place is static, and the Turning radius that makes vehicle is zero, and makes automobile realize the no-radius pivot stud.For example, if the wheelbase of automobile is 2600mm, wheelspan 1480mm, for realizing the no-radius pivot stud, the axis of each wheel must be by the geometric centre of automobile, this moment, each wheel all will inwardly rotate about 60 °, and common deflector is to rotate so big angle, and the finishing bevel gear cuter deflector can be accomplished.

Description of drawings

Fig. 1 is the scheme drawing of motor turning operation in the conventional art.

Fig. 2 is the block diagram of automobile electronic steering system in the conventional art.

Fig. 3 is the structural representation of the deflector in the automobile electronic steering system of the present invention.

Fig. 4 is to use the scheme drawing of the realization automobile no-radius pivot stud of deflector of the present invention.

Fig. 5 and Fig. 6 are to use deflector of the present invention to make the scheme drawing of wheel steering.

The specific embodiment

Describe the deflector of automobile electronic steering system of the present invention with reference to the accompanying drawings in detail.

As shown in Figure 3, the deflector in the automobile electronic steering system comprises bonded assembly motor 1, speed reduction gearing 2, transmission device 3 and bevel gear set 5 successively.

Wherein, when motor turning, the best angle relation that calculates gained by ECU rotates motor 1, passes motion to automotive wheel 4 by speed reduction gearing 2, transmission device 3 and bevel gear set 5 then, and wheel 4 is rotated.

Motor 1 and retarder 2 can adopt general structure, this be need not elaborate.Transmission device 3 generally can use a pair of Hooke's joint, and an end that connects with the bevel gear set certain-length that can freely stretch wherein is to adapt to beating of the middle wheel that travels.Bevel gear set input shaft and universal-joint link, and output shaft can become 90 ° with input shaft, is bound up by key joint and wheel rate.Wheel nave need be made an axis and the approaching hole of wheel main pin axis in advance when making, so as with the finishing bevel gear cuter output shaft coupling.

Bevel gear set 5 comprises intermeshing bevel- gear sett 51 and 52, and finishing bevel gear cuter 51 (for the sake of clarity, the back is referred to as first finishing bevel gear cuter 51) is connected the clutch end of transmission device 3, is used to accept the power from motor 1; Finishing bevel gear cuter 52 (for the sake of clarity, the back is referred to as middle tap gear 52) and 51 engagements of first finishing bevel gear cuter, and the axis of its axis and first finishing bevel gear cuter is perpendicular.Middle tap gear 52 is fixedly mounted on the wheel nave 41, and wheel nave can be made an axis and the approaching hole of wheel main pin axis in advance when making, be used for and the finishing bevel gear cuter output shaft between be bound up with key joint.

As shown in Figure 5 and Figure 6, motor 1 drives 51 rotations of first finishing bevel gear cuter by traditional mechanism 3, drives 52 rotations of middle tap gear then.Because middle tap gear 52 is fixed together with the wheel hub 41 of wheel 4,, turn to so drive wheel 4 for example by key joint.

Owing to adopted bevel gear set 5, so can make the rotational angle of wheel unrestricted.The conventional steering device, no matter pinion and-rack, circulating ball type or worm screw stylus pin formula, all be to rely on steering trapezoidal arm (or tooth bar) to drive tierod, spurring wheel again realizes turning to, because this structure is to lean on the sway of steering trapezoidal arm (or tooth bar) to spur wheel, so because steering trapezoidal arm sway space is limited, the corner of wheel is also limited.And the finishing bevel gear cuter deflector can not take up room in the wheel steering process in addition, so can not interfere with other parts, the rotational angle of wheel can reach 60 degree at least.

For the automobile of front-wheel steering, cover deflector of the present invention can be installed separately on the front-wheel of the left and right sides.For four wheel drive and the automobile that turns to, cover deflector of the present invention can be installed separately on four wheels also.According to the control signal of ECU, every cover deflector can independently be controlled, thereby the steering operation of automobile is very flexible, and wheel can rotate arbitrarily angled in theory.

As shown in Figure 4,, be installed in four deflectors of the present invention of the quadruplet on the wheel respectively, can realize that automobile rotates in the original place with no-radius by independent control for four wheel drive and the automobile that turns to.

Claims (3)

1, the deflector in a kind of automobile electronic steering system, this deflector comprises bonded assembly motor, speed reduction gearing, transmission device and bevel gear set successively.

2, deflector as claimed in claim 1, wherein said transmission device comprises a pair of Hooke's joint.

3, deflector as claimed in claim 1, wherein said bevel gear set comprise first finishing bevel gear cuter and the middle tap gear that axial one-tenth 90 degree intersect.

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