JPS61196866A - Front/rear wheel steering device for vehicle - Google Patents

Abstract

PURPOSE:To improve the operation of vehicle while to prevent unnecessary manual selection and to prevent abrupt variation of motion characteristic by constructing to disable manual changing operation for realizing the rear wheel steering angle ratio of steering angle except when the shift position of speed change lever is in low speed stage. CONSTITUTION:Upon provision of car speed 32, position 33 of slider 27, shift position 37 of speed change lever 36 and selecting information of selecting switch 34 to a computer 31, the car speed 32 is converted into a steering ratio signal which is compared with the slider position 35 to operate a steering angle ratio correcting information which is employed together with the selecting information 34 for driving a motor 29 thus to control the position of the slider 27. Here, manual modification of selecting switch 34 is disabled except when the shift position signal 37 of speed change lever 36 is in the low speed stage. With such arrangement, the operation of vehicle is improved resulting in prevention of unnecessary manual selection.

Description

DETAILED DESCRIPTION OF THE INVENTION <Field of Industrial Application> The present invention relates to an improvement in a front and rear wheel steering device for a vehicle that variably controls the steering angle of the rear wheels relative to the front wheels.

<Prior Art> The present applicant has already developed a vehicle steering system (patent application) that steers the rear wheels in conjunction with the steering of the front wheels and also varies the steering angle ratio of the rear wheels to the front wheels according to the vehicle speed. 57-134888, etc.). An overview of this device is as follows.
At low speeds, the rear wheels are steered in opposite phase to the front wheels or almost at zero.
On the other hand, at ^ speed, the rear wheels are steered in the same phase as the front wheels. As shown in 1) in Fig. 6, this steering angle ratio becomes a continuous function of the vehicle speed, and at a predetermined vehicle speed d1
If the vehicle speed becomes higher than this boundary, the steering angle ratio becomes il-
,, that is, they are in the same phase, but if the vehicle speed becomes lower than this, the steering angle ratio becomes negative, that is, the phase is opposite. Continuous control of the steering angle ratio is carried out according to this 11 curve, and the function of the steering system is achieved at both low and high speeds. This significantly reduces the vehicle's minimum turning radius and inner wheel difference to 6 at low speeds, dramatically improving the maneuverability of small wheels when parking in a garage, driving on narrow curved roads, knee turns, etc. J if you can do it
(On the other hand, at high speeds, maneuvering responsiveness can be dramatically improved.

By the way, when parallel parking in a narrow space at low speeds, if the front and rear wheels are steered in opposite phases, the rear of the vehicle may swing sideways. This may cause an inconvenience, and steering in the same phase may actually make steering easier.

Therefore, by providing a manual switching means in such a front and rear wheel steering device, such a demand can be met.

However, if the manual selection state is maintained, for example, in a medium to high speed range, the maneuvering response of the vehicle is not necessarily appropriate, and the motion of the vehicle may go against the driver's wishes.

<Problems to be Solved by the Invention> In view of these inconveniences, the main object of the present invention is to significantly improve the maneuverability of the vehicle by providing a manual switching means; If the 2-7 full selection status is inappropriate, Mayukoal switching form 1
To provide a front and rear wheel steering device for a vehicle such as 1.16 which automatically and forcibly releases the brake.

Means for Solving the Problems> According to the present invention, such an object is achieved by using a front and rear wheel steering system of a vehicle that varies the steering angle of the rear wheels according to certain conditions. Select one or more pieces of steering angle ratio information or rear wheel turning angle information and the steering angle ratio information or rear wheel turning angle information to realize the steering angle ratio or rear wheel turning angle corresponding to the selected information. manual switching means,
A front and rear wheel steering device for a vehicle, characterized in that the control means detects the shift position 0 of a speed change lever and stops the operation of the manual switching means when the shift position 1 to 1 is other than a low speed gear. This is achieved by providing

In particular, it is preferable that the manual switching state is canceled and/or started with a l1Sl delay.

<Function> In this way, when the shift position of the speed change lever is changed to a medium-high speed position, that is, when the vehicle's traveling speed reaches a certain level, the operation of the manual switching means is stopped, and the axle is switched to the driving position. Maneuvering response that goes against people's wishes♀
It is possible to overcome the inconvenience of In particular, II,' for starting and/or stopping the operation of the manual switching means.
By allowing a delay of J, it is possible to reduce the change in the vehicle's steering response to a sudden change.

<Embodiments> Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

In the drawings, Figure 1 is a perspective view of a vehicle equipped with a front and rear wheel steering system, not showing the general basic structure, Figure 2 is an enlarged perspective view of the rear wheel steering system, and Figures 3 (a) and (b). and (C) is a cutaway side view showing its operating principle.

First, in order to clarify the present invention, the configuration and operation of the front and rear wheel steering device will be explained with reference to FIGS. 1 to 3.

The handle shaft 2 of the handle 1 is incorporated into a rack and pinion type gear box 3, and tie rods 5.5 are connected to the left and right ends of the rack shaft 4, and the front wheels 7 are connected to the outer ends of both tie rods 5.5. A knuckle arm 6.6 carrying a wheel 7.7 is connected, and the front wheel 7.7 is steered in the steering direction of the steering wheel 1, as is known.

On the other hand, a rear hennion shaft 8 is led out from the gear box 3, and a long linkage shaft 10 is connected to the rear end of this shaft 8 via a universal joint 9.

A human power shaft 12 is connected to the rear end of the linkage shaft 10 via a universal joint 11. is supported by.

Furthermore, a second
As shown in detail in the figure, 1 moving shaft 15 is connected, and this 1 issen shaft 1
A joint member 16 is loosely fitted in the middle of 5. There are ball joints 17 and 17 at the left and right ends of this joint part 4416.
The tie rod 18 is connected via the link 21, 22 and the brackets 1 to 23, and the tie rod 16 is
1:t on the car body side? ) J is freely supported. In addition, both ties [J Rad 18.18 at the outer end of the rear wheel 20.20
A knuckle arm 19.19 supporting the is connected.

An arm 25 is fixed to the rear end of the swing shaft 15 so as to protrude downward, and a link 26 is pivotally connected to the lower end of the arm 25 so as to be rotatable in the vertical direction.
A slider 27 is similarly pivotally mounted to the rear end of the slider 6 so as to be freely rotatable in the vertical direction.

As shown in FIG. 3, an output shaft 30 of a motor 29 is screwed into the slider 28 via a ball screw mechanism 28, so that the output shaft 30 is coaxially located rearward with the input shaft 12. A motor 29 is fixed to the vehicle body.

On the other hand, the vehicle is equipped with an on-board computer 31, which receives signals from a vehicle speed sensor 32 that detects the vehicle speed and a position sensor 33 that detects the position of the slider 27, and outputs appropriate control signals according to the vehicle speed. motor 2
Supply to 9.

When the slider 27 is in the position shown in FIG. 3(a) and the pivot point P of the shimmed member 16 is aligned with the axis of the input shaft 12, the input shafts 12 and j: are referred to as the moving shaft 15. Since the joints 1 and 16 rotate concentrically, the joint members 16 are swung left and right i) J t! The tie remains unchanged at 18.18. Therefore, only the front wheels 7.7 are steered and the rear wheels 20.2
0 is not steered at all.

On the other hand, when the iI speed is lower than the set value d1 (Fig. 6), the computer 31 drives the motor 29 in response to the l+speed low signal from the medium speed sensor 32 as shown in Fig. 3 (b).
), the Q position of the slider 27 is set at the forward position. When the slider 27 is at the forward position, the swing shaft 15 is tilted downward, and the pivot point P is 01 below the axis of the input shaft 12. [Due to pull-off (eccentricity), the joint 1 member 16 swings left and right according to the rotation of the input shaft 12, displacing the rear wheel tie 18.18 in the opposite direction to the front wheel tie rod 5.5. .Therefore, the rear wheel 20.20 is the front wheel 7.
7, and the steering angle ratio of the rear wheels changes continuously in accordance with the vehicle speed.

Further, when the vehicle speed exceeds the set value d1 (FIG. 6), the computer 31 reverses the motor 29 in accordance with the vehicle speed at (), and moves the slider 27 backward as shown in FIG. 3(C). As the slider 27 retreats, the swing shaft 15
tilts upward, and the pivot point P is offset above the axis of the input shaft 12 by a distance e, so that the jicoin 16 swings left and right in accordance with the rotation of the input shaft 12, and Displace the tie rod 18.18 in the same direction as the tie rod 5.5 for the 61 working wheel. Therefore, the rear wheel is 20.20 and the front wheel is 7.7.
The steering angle ratio of the front small wheels also changes continuously in accordance with the vehicle speed.

Next, the main structure of the present invention will be explained with reference to FIGS. 4 to 6. FIG. 4 is a main part configuration diagram, FIG. 5 is a functional block diagram of FIG. 4, and FIG. 6 is a steering angle pressure characteristic diagram in the second diagram.

First, in FIG. 4, reference numeral 34 indicates, for example, a plurality of push buttons 3.
5a, 35b... is a steering angle ratio (or rear wheel steering angle, hereinafter the same) manual selection switch configured by arranging 5a, 35b...
It is placed on the instrument panel inside the vehicle so that the driver can manually operate it. This selection switch 3
4 is connected to the computer 3], and the selection switch 3
The selection result of the steering angle ratio selected in step 4 is displayed on the computer 31.
is man-powered.

A shift 1-position detecting sensor 37 is disposed near the bottom of the shift lever 36, and is designed to detect the shift 1-position of the shift lever 36. In the illustrated embodiment, the shift position detection sensor 37 is [o − J and 1
It consists of a limit switch installed at a shift position other than [back]. However, the configuration of the sensor is not limited to the above, and switches may be provided at all shift 1 positions, or switches may be provided at 1-output, back, and 1-neutral positions. The switch to the mechanical limiter 1 may be any type of switch such as an f-light sensor. If an automatic transmission is used,
It would be advantageous to arrange such a sensor inside the automatic transmission and similarly detect the shift state of the transmission gear.

Next, referring to FIG. 5, the manual selection function of the steering angle ratio in the pump coater 31 will be explained.

First, the normal operation (automatic operation!lI) in which the steering angle ratio automatically changes depending on the traffic will be explained. This is selected by pressing the first push button 35a of the selection switch 34. As described above, the low speed signal i) detected by the vehicle speed sensor 32 is input to the converter 31, and is converted into steering angle ratio data ka corresponding to the vehicle speed by the conversion process (a). On the other hand, the actual steering angle ratio f-ta kb is obtained from the position sensor 33, and both steering angle ratio data kk are subjected to comparison processing (a'b) to obtain the necessary steering angle ratio positive information b1. can get.

On the other hand, the selection switch 34 selects the
Since A is selected, the correction information b1 is outputted from the computer 31 by the selection process (c), and the steering angle ratio is changed to the required steering angle ratio according to the vehicle speed via the output device 39. A control signal S1 is supplied to the motor 29.

On the other hand, predetermined steering angle ratio information (d) is stored in the storage device of the computer 31. This information (d) is, for example, 1, k2, k3 for multiple pieces of steering angle ratio data having arbitrary sizes.
,...kn. Then, when the selection switch F-34 is pressed, C, any pushbutton other than the entry pushbutton 35a, for example pushbutton 35b, 1 is read out from the rudder angle ratio information (d) to the rudder angle ratio data. , this is compared with the steering angle ratio data kb from the position sensor 33, and the correction information b2 is 1! I get caught.

- On the other hand, in the selection process (c), if a push button other than auto activation A1 in the selection switch 34 is pressed, the output of the correction information b1 is stopped in response to this; The correction information b2 is selected to be output. This fixes it! , l1tll signals S2 are supplied from the output device 39 to the motor 29, and the steering angle ratio of the rear wheels is set to 1.

This operation applies to the other pushbuttons 35b, 35a...
6, and the driver can manually select any steering angle ratio kSk2, k3, . . . ko shown in FIG. 6 using the selection switch 34.

(t! fj, shift position fa on computer 31
T? To the shift position signal obtained from +137! With all due respect, the judgment process (to) is executed. In this judgment process (to), it is determined whether the shift position is at a low speed position, that is, "a-J,"("back" or "Nicole 1-Lar"). If the position is other than the low speed position, that is, the high speed position, the judgment result is returned to the selection process (c), and the output of correction information b2 for performing manual correction jf is regulated.

In other words, when the steering angle ratio is being corrected by ○ to auto operation, if the shift position is at the high speed position,
Even if manual correction is attempted with the manual selection switch 34, the selection process (c) maintains the state of auto-activation AI and does not shift to manual operation, and manual operation is not performed for an appropriate time until the shift l-position is set to the low speed position. d
Start gradually with this. Additionally, if a manual selection is made with the shift L position at the low speed position, and then the shift 1 position is shifted to the high speed position, the manual selection will be automatically regulated and the automatic operation will be delayed. It will start gradually. At this time, it is preferable that the manual selection state be completely canceled when the shift position is set to the high speed position, but unless the manual selection switch 34 is manually canceled, the manual selection state will be saved and the shift 1 to position will be The operation may be resumed upon returning to the low speed position.

Note that various processes in the computer 31 may be executed by predetermined control programs (rough 1 to software) stored in, for example, a storage device in the computer 31.

In the above embodiment, the on-vehicle computer 31 is used, but an electrical circuit or mechanical configuration having this turning function may also be used.

Although the steering angle ratio of the front and rear wheels can be manually selected using the position sensor 33 and the manual selection switch 34, the rear wheel steering angle may also be selected in the same manner.

Historically, the present invention is not limited to the embodiments described in 1-1, but may include a front and rear wheel steering system in which the front and rear wheels are hydraulically steered and front wheel steering angle information is transmitted to the hydraulic pressure, or a front wheel steering angle is transmitted electrically. It can be similarly applied to a front and rear wheel steering system, etc., in which transmission 1' is transmitted to the combination J-taper 31 at E.

Furthermore, by variously changing the operating conditions of the d-delaying means attached to the manual switching means as necessary, it is possible to ensure that the vehicle's handling responsiveness does not go against the driver's wishes under any circumstances. J is good.

<Effects> As described above, according to the present invention, the steering angle ratio of the rear wheels that slide relative to the front wheels is variable in accordance with the vehicle speed, etc. The ability to manually change the desired steering angle ratio at will improves the maneuverability of the vehicle, and also prevents the driver from selecting the steering angle when manual operation is not required. I
This has the effect of avoiding a situation that would impair control response.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing a schematic M-tree structure of a vehicle equipped with front and rear wheel steering devices. FIG. 2 is an enlarged perspective view of the rear wheel steering system. Figures 3(a), (b), and (c) are cutaway side views showing the operating principle of the rear wheel steering system, and Figure 4 is a diagram showing the configuration of the main parts. FIG. 5 is a functional block diagram of FIG. 4. FIG. 6 is a steering angle ratio output characteristic diagram in FIG. 5. 1... Handle 2... Handle shaft 3...
G) 7 boxes 4...Rack shaft 5...Tie rod 6...Buckle arm 7...Front wheel
8... Binion shaft 9... Universal joint 10
... Linkage shaft 11 ... Own RF joint 12.
... Input shaft 13 ... Bearing bracket 14 ... Clevis 15 ...) 1fJl shaft 16 ... Joint member 17 ... Ball joint 18 ... Tie rod 19 ... Knuckle arm 20 ... Rear Ring 21.22・
...Link 23...Bracket 1-25...Arm 26...Link 27...Slider 28...Pole screw mechanism 29...Motor 30...Output shaft 31...
Computer 32...Vehicle speed sensor 33...Position a sensor 34...Selection switch j35 a to 35d...
・Push button 36...Shift lever 37...Shift position sensor 39...Output device δ Patent applicant: Honda Motor Co., Ltd.
Attorney Yo Oshima - Figure 2 Figure 3 (b) (C) Figure 4 *sv! J Fig. 6 (Same order) (Weirshioorder)

Claims (2)

[Claims] (1) In a front and rear wheel steering system of a vehicle that variably controls the steering angle of the rear wheels according to certain conditions, one or more preset steering angle ratio information or rear wheel steering angle information; A manual switching means that selects steering angle ratio information or rear wheel steering angle information and realizes a steering angle ratio or rear wheel steering angle corresponding to the selected information; A front and rear wheel steering system for a vehicle, comprising: a regulating means for stopping the operation of the manual switching means when the speed gear is not a low speed gear. (2) The front and rear wheel steering device for a vehicle according to claim 1, wherein the regulating means stops and/or starts the operation of the manual switching means with a time delay.