CN103253296B - Vehicle steering apparatus - Google Patents

Abstract

The present invention provides vehicle steering apparatus.Transmission ratio changeable mechanism (30) it is provided with in the midway of steering spindle (2), this transmission passes through to be transferred to after the rotation rotating the rotary shaft adding motor of the first axle (4a) to steering wheel (1) side second axle (4b) of deflecting roller (8) side than changeable mechanism (30), so that the transmission ratio between the first axle (4a) and the second axle (4b) is variable.In transmission, changeable mechanism (30) is provided with the locking mechanism for limiting its action.When the pace of change torque acting on steering spindle (2) being detected exceedes the situation of fixing speed, presumption acts on the time required till the torque of steering spindle (2) reaches torque decision content.With this presumption time situation within the stipulated time as condition, transmission is made to work than the locking mechanism of changeable mechanism (30).

Description

Vehicle steering apparatus

Technical field

The present invention relates to a kind of vehicle steering apparatus, it possesses the operational ton pair that can make the steering wheel with vehicle Changeable mechanism is compared in the transmission of the steering volume change of the deflecting roller answered.

Background technology

In the past, as such vehicle steering apparatus, such as, it is known to described in Japanese flat 11-1175 publication Device.In the vehicle steering apparatus described in Japanese flat 11-1175 publication, steering spindle is divided into the of steering wheel side One axle and the second axle of deflecting roller side.Between the first axle and the second axle, it is provided with and makes their transmission than variable transmission ratio Changeable mechanism.Additionally, transmission is than the ratio of the anglec of rotation with the anglec of rotation of the first axle representing the second axle.According to such vehicle with turning Fore-and-aft motion, it is possible to change transmission ratio according to the operating condition of vehicle such that it is able to make corresponding with the operational ton of steering wheel The variable quantity change of the steering angle of deflecting roller.Thus, the operability of vehicle improves.

But, in such vehicle steering apparatus, if such as when vehicle travels, deflecting roller more goes up kerbstone And at deflecting roller by excessive shock loading, then this shock loading inputs as reverse via steering and the second axle Torque is transferred to transmission and compares changeable mechanism.If causing than the motor of changeable mechanism owing to this reverse input torque acts on transmission The rotary shaft of motor rotates against relative to the first axle, then there is the position at the handling maneuver angle of steering wheel and the steering angle of deflecting roller Relation of putting wrong from danger.

Then, in Japanese flat 11-1175 publication, the state of the load of monitoring motor, it is in the negative of motor detecting In the case of carrying high state, rotate than the rotary shaft of the locking mechanism restriction motor of changeable mechanism by being arranged to transmit, from And limit transmission ratio changeable mechanism action.If become motor load high shape due to input torque reverse to motor effect State, then limit the transmission action than changeable mechanism.Thus, the first axle is become and state that the second axle is directly linked, it is possible to press down Deviation between handling maneuver angle and the steering angle of deflecting roller of steering wheel processed.

But, in the vehicle steering apparatus described in Japanese flat 11-1175 publication, due to the sound of locking mechanism Should postpone, transmit the action than changeable mechanism from detecting the situation loading high state being in motor to start to physical constraints Till there will be a little time lag.If the rotary shaft of motor rotates against relative to the first axle during this time lag, then there is steering wheel Handling maneuver angle and deflecting roller steering angle produce deviation danger, this situation becomes makes the steer ability of vehicle be deteriorated One of the main reasons.

Summary of the invention

The present invention provides the vehicle steering apparatus of the steer ability that can improve vehicle.

According to an embodiment of the invention, it is characterised in that possess: transmission ratio changeable mechanism, it is by direction The second axle of deflecting roller side it is transferred to, so that above-mentioned first axle is with upper after the rotation rotating additional motor of the first axle of dish side State the transmission ratio between the second axle variable；Locking mechanism, it mechanically limits the rotation of said motor；Torque test portion, its Detection acts on above-mentioned first axle or the torque of above-mentioned second axle；And control portion, it detects in above-mentioned Torque test portion The pace of change of detection torque when exceeding fixing speed, utilize above-mentioned locking mechanism to limit the rotation of said motor.

Accompanying drawing explanation

Fig. 1 is the first embodiment for vehicle steering apparatus involved in the present invention, shows schematically electricity The figure of the brief configuration of dynamic power steering gear.

Fig. 2 is that the vehicle steering apparatus for this first embodiment represents the section structure transmitted than changeable mechanism The sectional view made.

Fig. 3 is the top view representing planar configuration for this transmission than the locking mechanism of changeable mechanism.

Fig. 4 is that the process that the locking mechanism for the vehicle steering apparatus making this first embodiment works represents The flow chart of the step of this process.

Fig. 5 A ~ Fig. 5 D is the sequential that the vehicle steering apparatus for this first embodiment represents its action example Figure.

Fig. 6 is the locking mechanism work for the second embodiment making vehicle steering apparatus involved in the present invention The flow chart processing the step representing this process made.

Fig. 7 is that the presumption process time of advent of the vehicle steering apparatus for this second embodiment represents at this The flow chart of the step of reason.

Fig. 8 A ~ Fig. 8 D is the sequential that the vehicle steering apparatus for this second embodiment represents its action example Figure.

Detailed description of the invention

By the detailed description referring to the drawings embodiments of the present invention carried out, the present invention above-mentioned and other Purpose, feature and advantage can become more fully apparent, wherein, and the labelling identical to identical element mark.

Hereinafter, referring to the drawings embodiments of the present invention are illustrated.

Hereinafter, with reference to Fig. 1 ~ Fig. 5, to being applied to by vehicle steering apparatus involved in the present invention, so-called tooth bar is auxiliary The first embodiment helping type driven steering device illustrates, and this tooth bar auxiliary type driven steering device is by right The rack shaft of vehicle gives the steering operation that auxiliary force assists driver.

In the driven steering device shown in Fig. 1, if operator steering wheel 1, then steering spindle 2 turns to based on it Steering force and rotate.Steering spindle 2 is by linking jackshaft 4 and pinion shaft successively at the steering stem shaft 3 linked with steering wheel 1 5 and constitute.Being linked with gear-box 6 in the bottom of pinion shaft 5, the rotation of steering spindle 2 is converted to rack shaft by this gear-box 6 The axial linear motion of 7.Then, the track rod that the linear motion of rack shaft 7 links via the two ends with this rack shaft 7 (omitting diagram) is transferred to deflecting roller 8, thus changes the travel direction of the steering angle of deflecting roller 8, i.e. vehicle.

It addition, be provided with quantity of state for detecting the operational ton of steering wheel 1, vehicle at this driven steering device Various sensors.The rotary angle transmitter 10 of the handling maneuver angle θ s of detection steering wheel 1 such as it is provided with at steering stem shaft 3.Little Gear shaft 5 is provided with the torque sensor 11 that detection acts on the torque tau of steering spindle 2.The speed of detection vehicle it is provided with at vehicle The vehicle speed sensor 12 of degree Vc.

In this driven steering device, rack shaft 7 is provided with electro-motor 9, and passes through from electro-motor 9 tooth Bar axle 7 gives torque to assist the handling maneuver of driver.Specifically, according to torque sensor 11 detection torque tau and Speed Vc of the vehicle of vehicle speed sensor 12 detection carrys out target setting auxiliary force.Then, so that from electro-motor 9 to rack shaft 7 The auxiliary force given becomes the mode of target auxiliary force, and the electric current of supply to electro-motor 9 is carried out feedback control.

On the other hand, in this driven steering device, jackshaft 4 is divided into the first axle linked with steering stem shaft 3 4a and the second axle 4b linked with pinion shaft 5.It is provided with between the first axle 4a and the second axle 4b and makes the first axle 4a and Two axle 4b transmit than variable transmission than changeable mechanism 30.

As in figure 2 it is shown, for transmission is than changeable mechanism 30, in the housing 33 being formed as approximation bottomed cylindrical Portion contains differential attachment 31 and motor 32.In upper wall portions 33a of housing 33, it is formed and the company that the first axle 4a spline is combined Knot 33b.Housing 33 via this linking part 33b with the first axle 4a can link in the way of rotating integrally.Motor 32 is with it Rotary shaft 32a is fixed on housing 33 with the mode of the central axis of housing 33.

Differential attachment 31 is known fluctuation gear mechanism, it possess a pair be set up in parallel coaxially spline 34,35, Spline 36 that the inner side of spline 34,35 is engaged with this spline 34,35 and the wavegenerator that the engaging piece making spline rotates 37。

First spline 34 is fixed on the inside of housing 33 in the way of coaxial with rotary shaft 32a of motor 32.Second spline 35 link with the second axle 4b via connecting member 38.Additionally, be respectively formed in the internal tooth quilt of first spline the 34, second spline 35 It is set as that there is the mutually different number of teeth.Spline 36 is configured at the inner side of spline 34,35 to bend to elliptoid state, outside it Tooth internal tooth with spline 34,35 respectively engages the most partly.In this differential attachment 31, if the first spline 34 is based on housing 33 Rotation and rotate, then the rotation of the first spline 34 is transferred to the second spline 35 and connecting member 38 via spline 36.By This, the rotation of the first axle 4a is transferred to the second axle 4b.

It addition, wavegenerator 37 is configured at the inside of spline 36, its central part links with rotary shaft 32a of motor 32. Therefore, if wavegenerator 37 rotates, then the mate between spline 36 and spline 34,35 along with the rotation of motor 32 Rotate.Now, reflecting that the number of teeth between the first spline 34 and the second spline 35 is poor, the second spline 35 is relative to the first spline 34 phase To rotation.Thus, the second axle 4b it is transferred to after the rotational delay of motor 32.Therefore, the rotation to the first axle 4a adds motor 32 Rotation after be transferred to the second axle 4b, thus the transmission ratio between the first axle 4a and the second axle 4b is changed.

Upper surface at motor 32 is provided with locking mechanism 40, and this locking mechanism 40 is by mechanically limiting rotary shaft The rotation of 32a limits the action transmitted than changeable mechanism 30.As it is shown on figure 3, locking mechanism 40 possesses is fixed on motor 32 The ring-type locking support 42 of one end of rotary shaft 32a and for the securing rod 43 by the spin locking of locking support 42.

Locking support 42 configures in the way of its central shaft is coaxial with rotary shaft 32a of motor.Outside locking support 42 Side face 42a is formed for multiple slots 41 of securing rod 43 engaging.

Securing rod 43 is configured at the radial outside of locking support 42, and is fixed in the rotary shaft 44 of the upper surface of motor 32 Supporting is for rotating.Securing rod 43 from the part extending partially into leading section 43a supported by rotary shaft 44, by spring Part 45 exerts a force to be allowed to the direction (direction shown in arrow a1 in figure) to towards locking support 42.Cardinal extremity at securing rod 43 Portion 43b is linked with drive shaft 46a of actuator 46.Actuator 46 attracts drive shaft 46a because of energising, thus composes securing rod 43 The torque given and lock on the direction (direction shown in arrow a2) that support 42 separates.Then, in the phase that actuator 46 is energized Between, securing rod 43 overcomes the active force of spring members 45 be maintained at and lock the position that support 42 separates.

Now, because rotary shaft 32a of motor 32 can rotate, it is possible to change first by the driving of motor 32 Transmission ratio between axle 4a and the second axle 4b.On the other hand, if cutting off the energising to actuator 46, then securing rod 43 is because of spring The active force of part 45 and rotate towards the direction shown in arrow a1, therefore the leading section 43a of securing rod 43 is connected to lock support 42 Outer peripheral face 42a.Now, if rotary shaft 32a of locking support 42 and motor rotates integratedly, then the leading section of securing rod 43 43a engages with slot 41, thus limits locking support 42 and the rotation of rotary shaft 32a.Thus, transmission is limited than variable machine The action of structure 30, thus become the state that the first axle 4a and the second axle 4b directly links, thus without turning to behaviour at steering wheel 1 Vertical generation deviation between angle and the steering angle of deflecting roller 8.

As it is shown in figure 1, transmission possesses the rotation angle sensor of rotation angle θ t for detecting motor 32 than changeable mechanism 30 13.The output of rotation angle sensor 13 is imported into the ECU(Electronic Control list being driven transmission than changeable mechanism 30 blanketly Unit: Electronic Control Unit) 39.Above-mentioned rotary angle transmitter 10, torque sensor 11 and vehicle speed sensor 12 Output be also directed into ECU39.Additionally, ECU39 is constituted centered by the microcomputer with memorizer 39a etc..

ECU39 output based on rotary angle transmitter 10 and vehicle speed sensor 12 controls to transmit the horse than changeable mechanism 30 Reach the driving of 32.Specifically, the handling maneuver angle θ s detected according to rotary angle transmitter 10 and vehicle speed sensor 12 detect Speed Vc of vehicle, the desired value of the rotation amount that computing is additional to the first axle 4a that is ACT instruction angle.It addition, ECU39 is according to rotation The actual rotation amount that first axle 4a is added of rotation angle θ t computing of the motor 32 of rotary angle transmitter 13 detection that is actual ACT Angle.Then, ECU39 controls motor 32 to make actual ACT angle follow ACT instruction angle.Thus, the rotation to the first axle 4a chases after It is transferred to the second axle 4b after adding the rotation of motor, thus the transmission ratio between the first axle 4a and the second axle 4b is changed.

It addition, ECU39 controls to transmit the locking mechanism than changeable mechanism 30 according to the torque tau that torque sensor 11 detects The driving of 40.Specifically, actuator 46 is energized by ECU39 in the normal state, turning of detecting according to torque sensor 11 Square τ and when reverse input torque being detected, cut off the energising to actuator 46.Hereinafter, to the process making locking mechanism 40 work It is described in detail.

First, in the driven steering device of present embodiment, if such as when vehicle travels, deflecting roller 8 is more gone up Kerb and at deflecting roller 8 by excessive shock loading, then this shock loading passes via rack shaft 7 as reverse input torque It is handed to steering spindle 2.This reverse input torque is transferred to transmission than variable machine via pinion shaft 5, the second axle 4b of jackshaft 4 Structure 30.

At transmission ratio in changeable mechanism 30, as in figure 2 it is shown, act on the reverse input torque of the second axle 4b via linking part Part the 38, second spline 35, spline 36 and wavegenerator 37 and be transferred to rotary shaft 32a of motor 32.Now, motor 32 According to acting on the size of reverse input torque of rotary shaft 32a and action as shown in following 1 ~ 3.Additionally, following 1 In ~ 3, motor operations breakdown torque τ m1 represents that motor 32 overcomes reverse input torque to enable rotary shaft 32a towards referring to normally Make the higher limit of the reverse input torque that direction rotates.It addition, motor limit holding torque τ m2(＞ τ m1) represent and can make rotation Under the reverse input torque that rotating shaft 32a overcomes the driving force of motor 32 and rotates towards the direction contrary with normal command direction Limit value.

1. reversely input torque is the situation of motor operations breakdown torque below τ m1.In the case of Gai, rotary shaft 32a can Rotate towards normal direction because of the driving force of motor 32.

2. reversely input torque exceedes motor operations breakdown torque τ m1 and the situation less than motor limit holding torque τ m2. In the case of Gai, rotary shaft 32a can not rotate towards normal direction because of the driving force of motor 32, it appears that stops.

3. reverse input torque is in the situation of the motor limit more than holding torque τ m2.In the case of Gai, rotary shaft 32a be because of anti- To input torque towards rotating with direction the most in opposite direction.

Then, as long as reaching motor limit holding torque τ at the reverse input torque of rotary shaft 32a acting on motor 32 Consider before m2 that operating lag makes locking mechanism 40 work, just can suppress handling maneuver angle and the deflecting roller 8 of steering wheel 1 Deviation between steering angle.

It follows that ECU39 execution makes the step of process that locking mechanism 40 works illustrate with reference to Fig. 4.Additionally, Processing shown in Fig. 4 was repeatedly executed at predetermined intervals with the execution cycle Tc of regulation in the period that the actuator 46 of locking mechanism 40 is energized.

As shown in Figure 4, ECU39 acts on the torque tau (step S1) of steering spindle 2 first with torque sensor 11 detection, And according to the torque tau computing its pace of change V τ (step S2) detected.In step s 2, ECU39 obtains and such as passes through step The difference of the torque that the torque that the process of S1 this time detects and the last time being stored in memorizer 39a detect, and this is poor Value is divided by execution cycle Tc, thus the pace of change V τ of computing torque.It follows that in step s3, this is detected by ECU39 The value of torque tau be stored in memorizer 39a.In the process shown in fig. 4, the process of this step S3 is performed every time, because of The data of the time series formula of this torque tau detected are stored in memorizer 39a.It follows that in step s 4, ECU39 sentences Whether the pace of change V τ of disconnected detection torque tau exceedes fixing speed V τ a, is fixing speed V at the pace of change V τ of detection torque tau In the case of below τ a (step S4: no), it is judged that for not producing reverse input torque, so that the processing returns to step S1.

On the other hand, in the case of the pace of change V τ of detection torque tau exceedes fixing speed V τ a (step S4: yes), ECU39 is judged as producing reverse input torque, and acts on the torque tau of steering spindle 2 according to the pace of change V τ computing of torque and reach Presumption time Te(step S5 to torque decision content τ th).Torque decision content τ th is set to said motor working limit Torque tau m1.It addition, in step s 5, ECU39 specifically estimates time Te according to below equation (1) computing.

Te=(τ th-τ)/V τ ... (1)

It follows that in step s 6, ECU39 judge presumption time Te whether at stipulated time below Ta, in the presumption time Te is in the case of stipulated time below Ta (step S6: yes), makes locking mechanism 40 work (step S7).On the other hand, pushing away The Te that fixes time exceeds schedule time (step S6: no) in the case of Ta, and ECU39 makes to the processing returns to step S1.Additionally, as with lock Determine time corresponding to the operating lag of mechanism 40 and set stipulated time Ta beforehand through experiment etc..

It follows that the action example of the driven steering device involved by present embodiment (is made with reference to Fig. 5 A ~ Fig. 5 D With) illustrate.

As shown in Figure 5A, if such as giving excessive shock loading at moment t0 to deflecting roller 8 and steering spindle 2 being acted on instead To input torque, then after moment t0, the torque tau acting on steering spindle 2 rises.And, as shown in Figure 5 B, in torque tau In the case of pace of change V τ exceedes fixing speed V τ a, ECU39 detects reverse input torque.It addition, as shown in Figure 5 C, ECU39 Pace of change V τ computing according to torque tau acts on the torque tau of steering spindle 2 and reaches the presumption time till torque decision content τ th Te.Additionally, at moment t0, because the presumption time Te calculated is longer than stipulated time Ta, so shown in Fig. 5 D, locking mechanism 40 Do not work.

Hereafter, as shown in Figure 5 C, if foreshortening to stipulated time Ta, then such as Fig. 5 D at the presumption time Te that moment t2 calculates Shown in, at this moment, ECU39 output makes the instruction that locking mechanism 40 works.In the present embodiment, because it is contemplated that locking mechanism The operating lag of 40 and set stipulated time Ta, even if so from the rotation confined moment of moment t2 to actually motor 32 Till t3, create the time lag of the time Tp caused because of the operating lag of locking mechanism 40, it is also possible to reach motor in torque tau The rotation of motor 32 is limited before limit holding torque τ m2.Specifically, in the torque tau acting on steering spindle 2 is in Fig. 5 A Time in the range of the point " τ th ＜ τ ＜ τ m2 " shown in hacures, it is possible to limit the rotation of motor 32.I.e., can be to motor 32 Rotary shaft 32a acting motors limit holding torque τ m2 before make locking mechanism 40 work.Then, present embodiment is electronic Power steering gear can suppress the handling maneuver angle of steering wheel 1 and the deflecting roller caused because of the operating lag of locking mechanism 40 Deviation between the steering angle of 8 such that it is able to improve the steer ability of vehicle.

On the other hand, as shown in double dot dash line in Fig. 5 A, if the torque tau acting on steering spindle 2 is reaching torque decision content τ Reduce before th, then, as shown in double dot dash line in Fig. 5 B, be down to fixing speed V below τ a at the pace of change V τ of moment t1 torque. In the case of Gai, as shown in double dot dash line in Fig. 5 D, ECU39 export the instruction making locking mechanism 40 work.Even if i.e. in basis In the case of the pace of change V τ of detection torque tau detects reverse input torque, motor 32 is not being made by locking mechanism 40 Work under situation with motor limit holding torque τ m2.Thus, the driven steering device of present embodiment can suppress lock Determine the misoperation of mechanism 40.

As described above, the driven steering device involved by present embodiment is used to be obtained in that following effect Really.

(1) driven steering device of present embodiment exceedes at the pace of change V τ of the torque acting on steering spindle 2 During fixing speed V τ a, the torque acting on steering spindle 2 according to the pace of change V τ presumption of torque reaches torque decision content τ th's Time Te.Then, to estimate time Te situation within stipulated time Ta as condition, locking mechanism 40 is utilized to limit motor 32 Rotation.Because this stipulated time Ta to be considered the operating lag of locking mechanism 40, it is possible to suppression is because of locking mechanism Deviation between handling maneuver angle and the steering angle of deflecting roller 8 of the steering wheel 1 that the operating lag of 40 causes, therefore vehicle turn Improve to maneuverability.It addition, under not situation to motor 32 acting motors limit holding torque τ m2, do not utilize locking mechanism 40 rotations limiting motor 32, therefore, it is possible to the misoperation of suppression locking mechanism 40.Additionally, held because motor 32 can be reduced The load being subject to, it is possible to realize miniaturization and the cost degradation of motor 32.

(2) torque decision content τ th is set as motor operations breakdown torque τ m1, is in other words set as that motor 32 overcomes instead The higher limit of the reverse input torque that can rotate towards normal direction to input torque.Thus, motor 32 is being acted on horse Before reaching limit holding torque τ m2, i.e. rotary shaft 32a of motor because of reverse input torque towards and side the most in opposite direction Before rotating, it is possible to utilize locking mechanism 40 reliably to limit the rotation of motor 32.Thereby, it is possible to suppress more reliably because of locking Deviation between handling maneuver angle and the steering angle of deflecting roller 8 of the steering wheel 1 that the operating lag of mechanism 40 causes.

Then, second embodiment of the present invention is illustrated.Additionally, the electric motor driven power steering dress of the second embodiment The basic composition put is identical with the driven steering device illustrated in Fig. 1.

The pace of change V τ of the torque tau that the ECU39 of present embodiment detects at torque sensor 11 be fixing speed V τ a with Acceleration A τ this respect and the first embodiment of obtaining the change of torque tau time lower are different.In the present embodiment, as expression The torque parameter of the variation pattern of the torque tau different from the pace of change V τ of torque tau and use the acceleration of the change of this torque tau Aτ.And, according to the acceleration A τ presumption of the change of torque tau to till motor 32 acting motors working limit torque tau m1 time Between, utilize mechanism 40 to limit the rotation of motor 32 in the case of the presumption time is stipulated time below Ta.Hereinafter, with reference to Fig. 6, Its detailed content is illustrated by Fig. 7 and Fig. 8 A ~ Fig. 8 D.First, with reference to Fig. 6, ECU39 execution made locking mechanism 40 work The step of the process made illustrates.Additionally, in managing in this place, by the process identical with the process illustrated in Fig. 4 is marked Identical labelling and the description thereof will be omitted, below, illustrate centered by both differences.

As shown in Figure 6, ECU39, will after calculating the pace of change V τ of the torque tau acting on steering spindle 2 (step S2) The value of this torque tau detected and the value of the pace of change V τ of torque tau calculated are stored in (step in memorizer 39a S8).In the process shown in Fig. 6, because the process of this step S8 is performed every time, so torque tau and its pace of change V The data of the respective time series formula of τ are stored in memorizer 39a.It follows that in step s 4, ECU39 judges torque tau Whether pace of change V τ exceedes fixing speed V τ a, (step in the case of the pace of change V τ of torque tau is fixing speed V below τ a Rapid S4: no), perform the presumption time of advent and process (step S9).

As it is shown in fig. 7, in the presumption time of advent processes, ECU39 first computing acts on the change of the torque tau of steering spindle 2 Acceleration A τ (step S10) changed.Specifically, the change of the torque of steering spindle 2 is acted on according to below equation (2) computing Acceleration A τ.

A τ=(V τ (n)-V τ (n-1))/Tc ... (2)

Wherein, (n) is this value, and (n-1) is the value of last time.

It follows that in step s 11, ECU39 is according to acting on the torque tau of steering spindle 2, its pace of change V τ, Yi Jiqi The acceleration A τ computing of change acts on the torque tau of steering spindle 2 and reaches the presumption time Te till torque decision content τ th.Specifically For, estimate time Te according to below equation (3) computing.

Te=(τ th-τ)/V τ+f1(τ)+f2(V τ)+f3(A τ) ... (3)

Additionally, the first function f1(τ with torque tau as variable), the second function with the pace of change V τ of torque tau as variable F2(V τ) and the 3rd function f3(A τ with acceleration A τ of the change of torque tau as variable) such as can be such as below equation (4) ~ (6) are defined.Additionally, B1, B2, C1, C2, D1, D2 are constant, and it is set by experiment in advance etc., transporting Can be regarded as the torque for steering spindle 2 and reach the presumption time Te till torque decision content τ th.

F1(τ)=B1 × τ²+ B2 ... (4)

F2(V τ)=C1 × V τ²+ C2 ... (5)

F3(A τ)=D1 × A τ²+ D2 ... (6)

After so calculating presumption time Te, ECU39 judges that in step S6 shown in Fig. 6 whether presumption time Te exists Stipulated time below Ta, in the case of presumption time Te is stipulated time below Ta (step S6: yes), utilizes locking mechanism 40 Limit the rotation (step S7) of motor 32.

It follows that the action example of the driven steering device involved by present embodiment (is made with reference to Fig. 8 A ~ Fig. 8 D With) illustrate.

As shown in Figure 8 A, such as when giving excessive shock loading at moment t10 to deflecting roller 8, steering spindle 2 is acted on Reversely during input torque, the torque tau acting on steering spindle 2 steeply rises in the way of proportional to the power in elapsed time.Should In the case of, the ECU39 of the first embodiment exceedes the moment t12 computing presumption of fixing speed V τ a at the pace of change V τ of torque tau Time Te.But, in the case of torque tau as in this embodiment steeply rises, it is possible to determine that go out in the computing of moment t12 The presumption time Te gone out is now at stipulated time below Ta.In the case of Gai, as in fig. 8d, ECU39 sends out in the moment of moment t12 The instruction of locking mechanism 40 of sening as an envoy to work.But, due to the time lag caused because of the operating lag of locking mechanism 40, locking mechanism 40 Actually in the moment work from moment t12 moment t14 after stipulated time Tp.Thus, the response of locking mechanism 40 Do not catch up with the rate of climb of the torque tau acting on steering spindle 2, may result in and can only exceed in the torque tau acting on motor 32 The rotation of motor 32 could be limited after motor limit holding torque τ m2.

In this aspect, the ECU39 of present embodiment torque tau pace of change V τ fixing speed V below τ a period, I.e. period from moment t10 to moment t12 is according to acting on the torque tau of steering spindle 2, its pace of change V τ and its change Acceleration A τ changed, as in fig. 8d computing presumption time Te.In this computing, with the presumption time Te of the first embodiment Computing compare and employ more parameter, therefore, it is possible to more accurately presumption time Te is estimated.Therefore, if estimate Between Te reach stipulated time Ta, then such as figure in moment not less than the moment t11 of fixing speed V τ a of the pace of change V τ of torque tau Shown in 8D, ECU39 output makes the instruction that locking mechanism 40 works.Thus, act on the reverse input torque of steering spindle 2 with In the case of the proportional mode of the power in elapsed time steeply rises, it is also possible to by the torque tau acting on steering spindle 2 Make locking mechanism 40 work time in the range of " the τ th ＜ τ ＜ τ m2 " shown in the hacures of Fig. 8 A midpoint, limit the rotation of motor 32 Turn.I.e., can limit by making locking mechanism 40 real work before to motor 32 acting motors limit holding torque τ m2 The rotation of motor 32.Thus, it is possible to that suppresses the steering wheel 1 caused because of the operating lag of locking mechanism 40 more reliably turns to behaviour Vertical deviation between angle and the steering angle of deflecting roller 8 such that it is able to improve the steer ability of vehicle further.

As described above, the driven steering device involved by present embodiment is used, except the first embodiment party Outside the effect of (1) and (2) of formula, moreover it is possible to obtain following effect.

(3) when acting on the pace of change V τ of torque tau of steering spindle 2 at fixing speed V below τ a, torque tau is obtained Acceleration A τ of change.It addition, reach the time Te of torque decision content τ th according to the acceleration A τ presumption torque tau obtained.So After, utilize locking mechanism 40 to limit the rotation of motor 32 with this presumption time Te situation within stipulated time Ta for condition. Thereby, it is possible to catch the situation of the reverse input torque that steering spindle 2 effect is exceeded torque decision content τ th more reliably and make lock Determine mechanism 40 to work.Thereby, it is possible to suppress more reliably between handling maneuver angle and the steering angle of deflecting roller 8 of steering wheel 1 Deviation such that it is able to improve the steer ability of vehicle further.

Additionally, for the respective embodiments described above, additionally it is possible to by suitably changing the respective embodiments described above and following The mode stated is implemented.

In the above-described 2nd embodiment, as representing different from the pace of change V τ of the torque tau acting on steering spindle 2 The torque parameter of the variation pattern of torque tau, uses acceleration A τ of the change of torque tau.This acceleration A τ can also be replaced and example As detection acts on the passage tendency of the torque tau of steering spindle 2, and this passage tendency is used as torque parameter.This situation Under, carry out pattern match, i.e. compare the passage tendency of the torque tau detected and pre-prepd passage pattern, thus computing turns Square τ reaches the presumption time till torque decision content τ th.It also is able to suitably detect by such method and exceedes torque judgement Whether the torque of value τ th acts on the situation of steering spindle 2.

In the respective embodiments described above, torque decision content τ th is set as motor operations breakdown torque τ m1, but as long as It is the value less than motor limit holding torque τ m2, just can be set as being worth arbitrarily.

The pace of change V τ of torque tau to act on steering spindle 2 can also exceed the situation of fixing speed V τ a as condition, Locking mechanism 40 is utilized to limit the rotation of motor 32.In the case of Gai, in process illustrated in above-mentioned Fig. 4, omit step The process of S5 and S6.

In the respective embodiments described above, act on the Torque test portion of the torque of steering spindle 2 as detection, and utilize electronic The torque sensor 11 of power steering gear, but the present invention is not limited to such mode.For example, it is possible to replacement torque sensing Device 11 and new torque sensor is set, it is also possible to suitably change torque sensor 11 configuration.Alternatively, it is also possible to according to electricity The current value presumption of the electro-motor 9 of dynamic power steering gear acts on the torque of steering spindle.In a word, it is possible to detection acts on and turns Torque to axle 2.

In the above-described embodiment, transmission is arranged at jackshaft 4 than variset 30, but such as can also will transmit It is arranged at steering stem shaft 3 or pinion shaft 5 than variset 30.

In the above-described embodiment, power steering gear is the driving force utilizing electro-motor 9 what is called as auxiliary force Driven steering device, but said apparatus can also be replaced and e.g. utilize oil pressure as the hydraulic power of auxiliary force Transfer.

The power steering gear of above-mentioned embodiment is the structure of the auxiliary force that rack shaft 7 gives electro-motor 9, but Auxiliary force can also give the optional position in handling maneuver transmission system.Can also be such as to pinion shaft 5 or steering column Axle 3 gives the power steering gear of the structure of auxiliary force.

Claims (4)

1. a vehicle steering apparatus, it is characterised in that possess:

Transmission ratio changeable mechanism, it is by being transferred to turn to after the rotation rotating additional motor of the first axle to steering wheel side Second axle of wheel side, so that the transmission ratio between described first axle and described second axle is variable；

Locking mechanism, it mechanically limits the rotation of described motor；

Torque test portion, its detection acts on described first axle or the torque of described second axle；And

Control portion, when the pace of change of the detection torque that it detects in described Torque test portion exceedes fixing speed, utilizes institute State locking mechanism and limit the rotation of described motor,

Described control portion by than described motor can be made to overcome the driving force of this motor and towards contrary with normal direction of rotation The value that the lower limit of the reverse input torque that direction rotates is little, as torque decision content, in the pace of change of described detection torque When exceeding described fixing speed, estimate described detection torque according to the pace of change of described torque and reach described torque decision content Time, and with time of deducing situation within the stipulated time as condition, utilize described locking mechanism to limit described motor Rotation.

Vehicle steering apparatus the most according to claim 1, it is characterised in that

Described torque decision content is set to described motor and overcomes reverse input torque can rotate towards normal direction of rotation The higher limit of reverse input torque.

Vehicle steering apparatus the most according to claim 1 and 2, it is characterised in that

Described control portion obtains the variation pattern of the described detection torque representing different from the pace of change of described detection torque Torque parameter, and reach the time of described torque decision content according to the described detection torque of presumption of described torque parameter, with presumption The time gone out situation within the described stipulated time is condition, utilizes described locking mechanism to limit the rotation of described motor.

Vehicle steering apparatus the most according to claim 3, it is characterised in that

The acceleration of the change that described control portion obtains described detection torque is used as described torque parameter.