JPS6223872A - Rear wheel steering device - Google Patents

Abstract

PURPOSE:To improve turning performance, by a method wherein, based on detecting signals from steering angle detecting means for front wheels and rear wheels, a rear wheel steering signal is outputted so that a wheel steering center is coincided with a steering center responding to a front wheel steering angle. CONSTITUTION:A front wheel steering device transmits the rotation force of a steering wheel to a knuckle arm 17 through a pinion 13, a rack 12, and a tie rod 14 through rotation control of a steering wheel 10 to steer front wheels 16. A rear wheel steering device transmits the rotation force of a motor 23 to a shaft 29 through a work mechanism 25, and transmits it to a knuckle arm 21 through a pitman arm 30 and a tie rod 22. In which case, steering angle detecting means 18 and 32, detecting the steering angles of front wheels and rear wheels, respectively, are provided. By means of detecting signals from the two detecting means 18 and 32, a control device 31 generates a rear wheel steering signal, by means of which a rear wheel steering center is coincided with a steering center responding to a front steering angle, and this controls the motor 23.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a rear wheel steering device for four-wheel steering of vehicles such as automobiles, and particularly to a rear wheel steering device for four-wheel steering of vehicles such as automobiles, and particularly for reducing running resistance and The rear wheel steering system is designed to reduce wheel wear.

[Prior art] In recent years, four-wheeled vehicles such as automobiles have been able to steer not only the front wheels but also the rear wheels, making it possible to drive the vehicle in a variety of ways that were previously impossible, and improving steering stability. The development of a four-wheel steering system is being promoted (JP-A-59-81258, JP-A-55-91458 #).

The basic concept of conventional front wheel steering is based on Ackermann geometry as shown in FIG. That is, when turning the vehicle body, the center point C of the front wheel steering that changes the direction of the pair of front wheels [, F5] is set to the fixed rear axle 10 extension line in the direction of the vehicle, and the four wheels are rotated. The steering center C of FL, F, l, RL, and RFL is made to coincide, and the vehicle body is turned around this matched steering center 0, and the front wheels FL on the inside and outside of the turning
The steering angle 98 of the front wheel [R on the inner side in the turning direction is larger than the steering angle θFL of
In the illustrated example, the vehicle is turning to the right, and the following relationship holds true: steering angle θFR of the front right wheel F and steering angle θFL of the front left wheel [L]. ). The specific structure of such Ackermann geometry is as shown in FIG. 12.
and a pair of knuckle arms 5 that rotate the front axle 4 around the king bin axis Kc in response to the steering wheel operating force outputted through the pair of tie rods 3 forming the output end of the steering mechanism 2.
It is satisfactory to install them respectively by tilting them inward toward the center of the vehicle body.

[Problems to be Solved by the Invention] Incidentally, in the above-described front wheel steering device, the steering wheel to the front axle 4 is connected in a certain relationship, and the front wheels FL and FR are connected to each other in a certain steering angle. Steering amount θFL,
θFR is uniquely set. Specifically, as shown by the solid line A in Fig. 13, in the right turning state (first quadrant), as the turning angle of the steering wheel increases, the left front wheel FL is steered from the neutral position (origin O) to the outside in the turning direction. The front wheels FL and FR are steered in a 1:1 ratio while the steering angle θFR of the right front wheel FR, which is on the inside in the turning direction than the angle θFL, is always set to a large value (a→b→c in the figure). ).

This is the opposite relationship even in the left turning state (third quadrant).
:1 correspondence is ensured (indicated by a → d → e in the figure).

).

However, when it comes to rear wheel steering, Figures 14 and 15
As shown in the figure, when making a turn with a large radius of curvature R that requires a small turning angle of the steering wheel, it is necessary to steer the rear wheels RL and RR in the same direction (same phase) as the front wheels FL and FR. When making a small turn with a radius of curvature r that requires a large steering angle, the rear wheels RL and RR
The key is to steer the front wheels in the opposite direction (in opposite phase) to the front wheels FL and FR. That is, in four-wheel steering, when turning the steered wheels, the front wheels FL and FR sequentially increase the steering angles θFL and θFR in the turning direction, whereas the rear wheels RL
, RR are once steered in the cutting direction, and then it is necessary to sequentially increase the turning angles θRL and θRR in the direction opposite to the cutting direction.

Here, if the steering device adopted for front wheel steering is directly applied to rear wheel steering and the above-mentioned same-phase/opposite-phase steering is performed, the result will be as shown in FIGS. 13, 16, and 17. For example, in a right turning state, the rear wheels RL and RR are initially θ
Due to the relationship RR>θRL, it is cut to the right (a→b) in the same phase (Fig. 16), and when it is further cut, the rear wheels RL and RR
are sequentially cut to the left (b→a→d→e) so that they are in opposite phase (FIG. 17). In this case, in the opposite phase (third quadrant), the relationship between the left rear wheel RL on the outside in the turning direction and the right rear wheel RR on the inside in the turning direction is reversed (θRL>θRR),
It becomes impossible to achieve smooth turning motion.

The same thing can be said even when the pair of knuckle arms are installed so as to be inclined outward toward the side of the vehicle body, as shown by the broken line B in FIG. 13.

In the end, the problem mentioned above is that the rear wheel RL, relative to the turning angle of the steering wheel,
This is an unavoidable result based on the front wheel steering device that can only uniquely give the steering angles θRL and θRR of the RR.

It is also conceivable to install a pair of knuckle arms parallel to each other along the vehicle length direction as shown by the two-dot chain line D in FIG.
Since the RRs are always the same, satisfactory turning performance cannot be obtained.

History, and 11 others. When steering the rear wheels, as with front wheel steering, it is necessary to set the turning center of the wheels RL.
'-e4111 The extension line of the diagram [IJV after IJV is 1)
1'l (generally the front wheel) -', ,
F. The steering center of the steering wheel R, , does not coincide with the steering center of r<R. This is noticeable in navigation systems where the steering wheel of the middle wheel is fixedly correlated.

(Toy) 1. The malfunction of the rear wheel steering has a negative effect on the turning performance during the mid-rest period, causing the wheels to slide sideways!
, the running resistance increased and the middle wheels were damaged (-).

``Invention October'' Objective 1 Invention 1 - In view of the problems mentioned above, the invention was invented. An object of the present invention is to provide a rear wheel steering device that can eliminate side-slip of the middle wheel, reduce running resistance, and suppress wear of the middle wheel.

[Overview of the Invention 1 The present invention (3L1 front wheel steering angle detection means 9, rear wheel steering angle detection stage 1, and detection signals from these detection means) correspond to the front wheel steering angle. The rear wheels are steered based on the output signal from the control device N, which outputs a rear wheel steering signal with the rear wheels 4+/2 centered on the steering wheel, and a rear wheel steering signal IL-1/2 that is centered on the rudder center. and a drive means for actuating the control device), the control device)) steers the rear wheels independently according to the output power of the eyes.
, it is sea urchin.

[Example 1] The spring wheel steering equipment according to the present invention will be revised according to the attached drawings below.

FIG. 2 shows a schematic configuration of the front wheels □7'y and the rear wheel steering device.

First, regarding the front wheel side (to explain, 10 is a steering wheel (V)), one end of a rotating shaft body 11 that transmits the rotational operation force (A) is connected to this steering wheel 10. This rotary shaft body 11 is equipped with a tooth width mechanism consisting of a rack 12 and a pinion 13 that converts rotational motion into one reciprocating motion at the other end. A pair of ties 1 transmits reciprocating power to
] The bolts 14 are rotatably connected. A knuckle arm 17, which is integrally attached to the front axle 16 via the knuckle 15, is rotatably connected to the tie rod 171. The front axle 16 rotates around the kingpin axis K0. Freely configured and can be used as an example I: Front wheels FL, F
It enables T20 steering. Also knuckle arm 17
is tilted inward toward the center of the corpuscle. Therefore, by turning the C1 steering wheel 10 to the right or left, the respective operating forces are sequentially applied to the rotating shaft body 11. It is transmitted to the knuckle arm 17 via the gear mechanism and the tie rod 14, and the knuckle arm 17
The connecting end 17a of is rotated around the kingpin axis KO, and the front axle 16 is rotated, and as a result, the front wheels FL, Fk have corresponding steering angles θFL, θF according to the turning angle θ of the steering wheel 10.
It is designed to be steered at 12. In particular, the rotating shaft body 11 is provided with a steering wheel angle detecting means 18 which is a front wheel turning angle detecting means for detecting the amount of rotation of the rotating shaft body 11 to detect the turning angle θ of the steering wheel 10, and detecting the turning angle of the front wheels. GJ is done.

On the other hand, FIGS. 1 to 3 show a pair of rear wheels RL.

A specific configuration of a rear wheel steering first stage 20 for rotating the rear wheels 19 around the kingpin axis K0 in order to respectively steer the RRs is shown. This rear wheel steering means 20 is installed independently for each of the left and right rear wheels RL and RI2. A tie rod 22 is attached to the knuckle arm 21 in the same manner as the front wheel side, and the tie rod 22 is attached to the ball shifter 1.

The other 23 is a motor serving as a driving means for preventing the knuckle arm 21 from operating.
A power transmission system 24 that converts the motor rotational force into reciprocating power of the tie rod 22 is interposed between the tie rod 3 a and the tie rod 22 .

Specifically, a reduction gear i mechanism 27 is provided on the output shaft 23a of the motor 23 and is composed of an A-arm 25 and a worm wheel 26 that meshes with the A-arm 25, and a worm wheel 26. A shaft 29 is attached and rotatably supported by a bearing 28 to transmit rotational force, and one end is spline-fitted to the shirt 1 and integrated with the shaft 29, and the other end is ball jointed to the tie [1] and the shaft 29. The pin 1 to 7-me 30 converts the same rotational motion of the shaft 29 into a reciprocating rocking motion and transmits the reciprocating motion to the tie rod 22. It has become.

Here, the control of the Tanabata 23 that drives the rear axle 19 to steer the rear wheels RL, R, is performed by the control + device 31 mentioned above.
Output signals θHOL, θ? 1e12
carried out by

In particular, as shown in FIG. 2, the shaft 29 detects the amount of rotation thereof and calculates the steering angle θRL of each of the rear wheels R, , R, and the like.
, θ12R, rear wheel steering angle detection means 32.
32 are provided.

Furthermore, as shown in FIG. 2 and FIG.
RL and θRR are calculated and the respective rear wheels RL and R are
A control device 31 for outputting R steering signals θMOL and θMclR is connected. This control device 31 is composed of an input section 33, a memory section 34, and a meter section 34. The goal is to calculate the correlation between the steering wheel angle 0, which is the front wheel steering angle, and the il transverse steering angle in order to match the rear wheel steering center with the front wheel steering center, which is 1, b?l for the angle. Setting f + I4 /76RL, 0 ovep Yme memory is stored.Also, the operator section (-33 is manually input from Me 1 section 34) Standard setting 4++ 0◇, L, θo
When the actual steering wheel angle is 0 with respect to B, the rear wheel turning angle θRL, (
To match hR, the detection signals θ, θRL,
/' RR is processed and the steering angle of C rear wheel r<, , R, is ¥30F4゜1.

OM. 3 is output (-). Further, the control device 31f is connected to the seventh controller 23, and outputs an output signal θ, f), . . . of the steering amount. 2 is human-powered by 923. tf (steering signal θRL for rear wheels R, , R).

0 pig is [one body (well, drive the rear width shaft 19 (IF reverse color H4θ8°0.θ of coater 23) IOR and INO U
The output J is exactly the same.

Next, the operation of the present invention will be described.

1-Explain! , τ, C for rear wheel steering is rear wheel 1<,
.

The RR itself can be steered.Secondly, its steering center is fixed compared to the conventional one.1. ``In the middle of the rear width axis III: fi direction h [■ Required for the quadrant I- (Fig. 11)-1゛()t) Existence 1!
-) - (Generally, the steering centers of the front wheels 1-, , l-, are the same 7, which means 4, Y front wheel steering (J adopted, front wheel steering //) 1 Stiff steering wheel '10's turning V) is unique for the angle θ (, which is unavoidable in a steering eutectic that can change the steering angle of the two wheels).Here, the steering μ( θ12L, θ, 5 as I
2 "I'J can be done independently", this problem is solved (I can do it, for example, in rear wheel steering) ζ is the same as 1
vinegar! If in-phase/out-of-phase steering is required (2 or this platform rear wheel RL, r Regarding front wheel steering in advance 1] [Align the steering center with the required rear wheel RL, I
−<H’s steering center shift 1jy is proposed by W1 −(steered wheel 1()
Corresponds to 0 and 0 angles of 1! -C Set to move and shake C
(1, rear wheel 1, 1.IQ is steering angle f) R
L, t) (・Since it can be done by turning the steering wheel, the setting is 1''.
11ζ front wheel "1° 1-R relative to the steering center, rear wheel R,,
It is possible to move the steering center by -f when t<, C. (See arrow 1 in Figure 6). By steering Rz at one turn of the rear wheels, the steering center C of the front and rear wheels can be made to coincide with each other. It is possible to improve the turning ability.
The steering center is aligned with the steering angle OFL, θFlie (corresponding to the steering center of the front wheels) of the front wheels [-1°F, which corresponds to the steering angle 0 of the steering wheel 10, at the meandering portion 34 of No. 1! The steering angle of the rear wheels RL and R12 to be obtained is 0.0°6□ in advance: i:t
This can be achieved with the device N.

L: In order to smooth the turning movement of the vehicle body, it is necessary to keep the turning radius of the inner turning wheel smaller than the turning radius of the outer turning wheel, and therefore it is necessary to maintain the turning radius of the inner turning wheel smaller than the turning radius of the outer turning wheel. Not only must the steering centers of the front and rear wheels be aligned, but also the steering angle of the rear wheel on the inside of the turning direction must always be greater than the steering angle of the rear wheel on the outside of the turning direction. be. For this,
” - The vehicle is turning in the direction of turning with the steering centers of the front and rear wheels aligned as described above [outward in direction 11 (in the case of a right turn, the direction of vehicle 11 is
This is possible by positioning or moving the rear wheel R,, t<, to the -4 direction (see Figure 6G). J-Re, align the steering center C of the front and contact wheels 11, 1
．． : The turning radius F of the inner wheel is smaller than the turning radius F11 of the outer wheel. 1ili
The steering angle θ of the steering wheel and the steering angle θ612L, 06*R of the rear wheels are correlated to the metering unit 34 of the rear control device 31.
! [It can be achieved with the device described in 1 by storing the memory value τ.

On the other hand, when steering the rear wheels, [well, when the turning angle θ of the steering wheels 10 is small (the turning radius of the vehicle body is narrow), the front and rear wheels are in the same phase, and the steering angle θ is large (the turning radius of the vehicle body is narrow). (small diameter) requires the rear wheels to be in opposite phase to the front wheels.

At this time, C is set at the neutral position (steering angle θRL, -0 to θ).
straight forward state), the extension line 1 of the rear width axis 19 in the direction
In contrast to y, it is necessary to position the steering center of the rear wheels behind it when the i'l phase is the same, and at the front of it when it is in the opposite phase. On the other hand, ゛( is the prefix that should be matched as described in
) This is possible by setting in advance the turning center C of the Q wheel so as to move in the vehicle length direction beyond the extension line F (see FIG. 11). Then, like this, the rear wheels RL, RIi!
By steering the front and rear wheels, the same phase of the rear wheels RL and Rk can be made to match the steering centers C of the front and rear wheels, and smooth phase control of the rear wheels RL and Rk can be performed to improve turning performance. This type of rear wheel steering is also performed by storing the front wheel FL in the memory section 34 which is stored above.

[The turning angle θ of the steering wheel and the steering angle θ of the rear wheels that control R. 5L
, 0°6R and memorize them, l-
It can be achieved with 100 notes. Further, the movement of the steering center O may be continuous.

In history, changing the turning radius of the vehicle body can be achieved by changing the phase of the rear wheels, which has been done for 11 years, but it is possible to change the turning radius of the vehicle body by moving the steering center C of the front and rear wheels and the extension line F in the vehicle length direction. There are cases where a sufficient effect cannot be obtained with only the strip A'1. That is, if the steering center when the phase is opposite is set far away in the direction of the inside of the vehicle, and the center of steering when the phase is the same is set close to the inside direction of the vehicle, the turning radius will not change much.

On the contrary, change the phase of the rear wheels2Z It is possible to vary the turning radius considerably from large to small (see Fig. 6 (■)). And like this, the rear wheel RL.

By steering the vehicle in one direction, turning performance can be improved by ensuring that the turning radii R1 and R2 can be changed while aligning the steering centers C of the front and rear wheels. In such rear wheel steering, the turning angle θ of the steering wheel and the steering angle θ0RL I θ of the rear wheel are also determined in the steering wheel portion 34.
This can be achieved with the L device by correlating and storing the mouth RR.

FIG. 6 shows the locus of movement of the steering center C, which is set in consideration of all of these regulations. That is,
1 with front wheel FL, FI2 and rear wheel 1. R8 steering center C
Both rear wheels RL to match.

Give independent steering angles θRL l 03□ to f<, respectively,
In addition, in order to smoothly turn the vehicle around the coincident steering center 0, the steering center C is positioned outward in 11 directions in the turning direction, and the phases of the rear wheels RL and RR are changed and the turning radius is changed. In order to ensure that the steering center C is in the same phase when the turning angle θ of the steered wheels is small and the turning radius is large, 1 & J, the turning angle θ of the steering wheel is large and the turning radius is small.
In the figure, the setting is such that the steering center C is continuously moved to ensure smooth turning motion. Especially the rear wheels RL, R
, phase change and turning angle θgL of the inner and outer wheels during turning,
The relationship with θRR is shown, for example, by the solid line in Figure 5 during a right turn; when the steering wheels are in the same phase with a small turning angle (a → b: first quadrant), the rear wheels Is the steering angle of RL and Ra R2>θLl? It is necessary to satisfy the relationship that
Furthermore, when the turning angle of the steering wheel becomes larger (b-+a→
(C→d: third quadrant), the steering angles of the rear wheels RL and RR must satisfy the relationship θ>θRL. On the other hand, even when turning left, as shown by the broken line, the rear wheels R and Rg
It is necessary to shift the steering angle from the same phase to the opposite phase while always maintaining the relationship θRL > θR12 (a → e → f → 0)
.

That is, the steering angle θ of the rear wheels RL and Rk, θ? R needs to be given two important correlations when turning to the right in the same phase and turning to the left in antiphase (first quadrant), or when turning to the right in antiphase and turning to the left in the same phase (third quadrant). This is because the control device 31 controls the memory section 34 that stores the relationship between the rear wheels RL and R, which can be steered independently.
'(: Achieved by controlling.

Based on the relationship shown in FIG. 5, the steering angle θ of the steering wheel and the steering angle θ of both rear wheels, which are not shown in FIG. θ. A. The relationship between the two is shown in the graph of Figure 7.

As shown in the figure, the turning angle θ of the steering wheel is plotted on the horizontal axis, with a positive value representing the right turning direction and a negative value representing the left turning direction. In addition, the vertical axis shows the steering angles θFL, θ, and θ of the four wheels, with 1 value representing rightward steering and a negative value representing leftward steering. RL'θ. 58 is taken. When turning to the right, the front wheels change steering angles θFL and θF1 as the turning angle θ increases, as before.
2 is increased to the right (positive direction). Also, when the turning angle θ is small, the rear wheels are steered to the right (forward direction) so that they are in the same phase (same quadrant) as the front wheels, and then when the turning angle θ becomes large, they are steered to the opposite phase (in a different quadrant). It is steered to the left (angular direction). At this time, front wheel 1-1j
M, h & pronation (right wheel) 0g > turning outer wheel (71 wheel) 0
The Seki 1 system of L is maintained.

/+'Ah when turning (is set similarly, front wheel is LJ)
As the steering angle increases, ft'll −)−(steering angle θFR, OF
As F is increased in the negative direction)/\\ towards )jl 'h,
Rear wheel j; l l;, II) As the J angle 0 increases, the wheel turns to the direction of f (toward the mouth) in ゛ (same 11゛I phase.j,) (after turning, right 1) The vehicle is steered in the direction (+r: lj direction).

Then, in this way, the preset value (\) is stored in the meter section 34 of the control 911 with the target value of ◆ρ control balance 1 and ().

Next, an example of control No. 1 will be explained with reference to FIG.

First, if the engine has been started (11i), if the engine has been started (NO, then FN +).

On the other hand, the first 11-ne (Iridoki (Y [S)) is the next 3t!
: 4'r, the current brightness angle θ of the steering wheel detected by the steering wheel angle detection means IEl IJ, which is the front wheel turning angle detection means.
Once loaded, proceed to the next step.

Steering wheel 01 t; Q 14.1 angle f) +, T 34"
d 6 i'19 Ni I/) control 11 II m
itl'i doto 1"1 mark steering angle 0°IZL,
When θe and B□ are read from the measuring part ζ34, the steering angle θ of l17,f is precisely calculated. k, 1゜0゜22, and drive means lζ to t--923. Next (42) 1f.

From the 1st to 290th rotation collapse, the actual steering angle t of the rear wheels R,, r<, -, (for li2., i>4' 6
Rear wheel steering angle detection which detects the actual rotation angle t) vw, 1) he [932°32 or l'> (one of these 0.L
, θH12 is included in the calculation t3 first], -Rear wheel R,
1, actually (1 self)
f) sL dot [standard (1st θHOL and difference Δ θCL jii &)〈Δ0c1. ．．
=, =θML OMoL) C1. :ra) missing(, 2M
um0, the absolute fraction (]ΔθcL l of the difference (ΔθCL)
) is 0, proceed to the next step.

The value of the difference (80CL) is set to the rth setting.The error range is
Δθ. CL > inside (Pa or fortune-telling? (1△θCL l≦2
Δ0o-i) is within the error range (YES >
``(''Aru 1, 71) Pono ■ New controls and controls are performed for the rear wheels R and kT, and the process proceeds to the next step for controlling the rear wheel Rk. Within the error range (△0°CL) - e I C I R R B (NO>; i Proceed to the next step to control the rear wheel RL.

Is the confession of the difference (ΔθCL) 1] (1 self? #i
It is determined whether there is 4h-C, and in the next control, the difference ΔfjcL is set within the error range Δθ. 1E(lI′f (
Y E S ) -c'drill/, rRIrff -Rotate the data 23 by i[, negative 11 white (N O) -(-') Roll the data 23 by jφ l! After that,
Proceed to the next step to control the right rear wheel l<5.

Below, I1 rear wheel Rg (Mo111 mouth 12 control)
[1- is performed. Here, the right rear wheel [<k or left ((wheel 1<.

〇 to the difference between either - nof. 1. Δ0cR is the error range Δθ
6CL +Δθ. If it is out of c8, the control] [1- is the actual t:- is returned to the previous stage of reading the rotation angle θ, and the actual values θHL, θHR, and target value θMO
L.

0M. Asymptotic control 111 with 5 is repeated (N in the figure
(see 4). On the other hand, there is a difference Δ between the rear wheel Rfe and the left rear wheel RLJξ.
θCL.

ΔθcR is Mi difference period ΔθOCL, within Δ0ooR (
- If there is, control II) [1- is returned to the stage before the engine start judgment, and the rear wheel steering control for the new steering wheel steering angle of 0 is continued (see N in the figure). (1) In the middle part of the four-wheel steering, the middle rest turning! 1!F When steering the middle wheel, the skidding of the wheels is lost, and the running 1) resistance [Reduction of wear] It is possible to achieve suppression of wear of width ring 1#.

9 and 10 show a modification of the rear wheel steering first stage 20.

As shown in FIG. 4, the steering means 20 transmits the steering force of the steering wheel, creates a pair of ties 22, and rotates the rear width axis around the steering wheel axis. The operating force transmission system 35 and this operating force jxi delivery system 3! ′j
, the two-point Senyusei south center mechanism 336, and the above-mentioned control device 31
The operation transmission system 35 is composed of a differential manual power transmission system 37 for each stage, and a differential freewheeling mechanism 36 that outputs an output signal from the front wheel steering system 37. The pinion 38 is meshed with the steering wheel and the pinion 38 is connected to this pinion 38, and the pinion 38 is connected to the pinion 38, and
An arm 41 that revolves around the sun tooth width 40 around the tooth center 39, and a pair of arms 41 that have one end fixed to the sun south center 40 and the inner south tooth center 42, and the other end connected to the tie rod 22 on the right. Arm 4: From 3 'tM Sei 2! i16. , Hp Ta difference I
J+ Manpower 1st level 37 Ha, l: -'I 44 and Shi-
The planetary gear 39 is rotated by the gear 44 and rotates 1! It is composed of a reduction gear system 45 and the like.

When the phases are the same, the motor 44 is not driven, and the planetary gear 39 is revolved by the operating force of the steering wheel, so that the internal tooth width 42 and the sun gear 40 are rotated in a constant relationship. In use, when the phase is reversed, the first gear 44 is reversed at a considerable speed according to the output signal, and the planetary gear 39 is reversed.
The sun gear 40. Considerable differential rotation is applied to the internal tooth width 42.

Of course, even if this steering means 20 is adopted, the same effects as in the above embodiment can be achieved.

[Effects of the Invention] In summary, according to the present invention, the following excellent effects are achieved.

(1) When steering the rear wheels, by giving each rear wheel an independent turning angle, the turning center of the rear wheels can be aligned with the turning center of the front wheels, improving turning performance. can.

t2) (,'t) Eliminates skidding of the middle wheel when steering the wheels such as when turning, reducing running resistance and suppressing wear of the middle wheel.

(3) a front wheel turning angle detection means, a rear wheel turning angle detection means, and a method for aligning the rear wheel turning center with the turning center corresponding to the front wheel turning angle based on detection signals from these detection means; The control device outputs the rear wheel steering speed, and the drive device differentially controls the rear wheel steering means based on the output signal of the illumination device. Appropriate rear wheel steering can be achieved.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of a rear wheel steering means showing a preferred embodiment of the rear wheel steering device according to the present invention, FIG. 2 is a schematic configuration diagram of the rear wheel steering device according to the present invention, and FIG. FIG. 4 is a schematic diagram of the control system adopted in the present invention, and FIG. 5 is a schematic diagram of the main part of the rudder means, and FIG.
Figure 6 is a diagram illustrating the relationship between the steering angles of the left and right rear wheels that satisfies the steering of the outer wheels; Fig. 6 is a graph showing the relationship between the turning angle of the steering wheel and the turning angle of the four wheels in order to change the moving trajectory of the steering center by 1q, Fig. 8 is a flowchart 1-diagram showing an example of the control flow, and Fig. 9 10 is a front view showing a differential planetary gear mechanism employed in another rear wheel steering means, FIG. 11 is a diagram showing Ackermann geometry, Figure 12 is a schematic configuration diagram showing the front wheel steering system, Figure 13 is a graph diagram showing the relationship between the steering angles of left and right wheels in the front wheel steering system, and Figure 14 is a schematic diagram showing the same phase state in four-wheel steering. Fig. 15 is a schematic diagram showing the opposite phase state in four-wheel steering, Fig. 16 is a schematic diagram showing the same phase state of the rear wheels when the front wheel steering device is used as is for rear wheel steering, and Fig. 17 is a schematic diagram showing the same phase state of the rear wheels when the front wheel steering device is used as is for rear wheel steering. FIG. 3 is a schematic diagram showing a reverse phase state of the rear wheels when the front wheel steering device is used as is for rear wheel steering. In the figure, 18 is a steering wheel angle detection means which is a front wheel turning angle detection means;
20 is a rear wheel steering means, 23 is a motor with one stage of the drive hand 25, 31 is an all control device, 32 is a rear wheel steering angle detecting means, F, , F= are front wheels, and RL and Rk are rear wheels. Special V [Applicant: Isuzu Motors Co., Ltd. Representative Patent Attorney
Nobuo Kinutani 26 1st to 1 FL OFR 0RL ○0RR Io・×. No. 1 - Bad book sale 1 ■ 1F rent 1 (method) Showa 6 (E November 14F + Commissioner of the Patent Office Uga Tori Department 1, Indication of matter I! 1 Patent application No. 161123/1982 2, Name of the invention After) Wheel steering device 3, correction lead person small I' Atago 111 Attorney Building 5, Amendment Order Rf ~ 1 October 29, 1985 (Shipped [1) 6, Drawings subject to amendment 7, Contents of amendment (1) Attached sheet Gogo < Created using Ako IIN the drawing
It comes out. 〈(The contents are not changed) 8. 11 records of companion animals

Claims (1)

[Claims] A front wheel turning angle detecting means, a rear wheel turning angle detecting means, and a rear wheel turning signal so as to align the rear wheel turning center with the turning center corresponding to the front wheel turning angle based on the detection signals from these detecting means. A rear wheel steering device comprising a control device that outputs an output signal, and a drive device that operates a rear wheel steering device based on an output signal from the control device.