JPS63227473A - Steering device for automobile - Google Patents

Abstract

PURPOSE:To prevent the occurrence of handle draw-in phenomenon in which a wheel is steered by an amount more than predicted, by a method wherein a transmission ratio varying means to vary a transmission ratio according to a car speed is located in a steering force transmission route, and during the transient state of a vehicle, a transmission ratio is fixed. CONSTITUTION:A transmission ratio varying device 10 to vary a transmission ratio being a ratio between the rotation angle of a steering handle 2 and the steering angle of a wheel 6 is located between a handle shaft 3 and an intermediate shaft 4 of a steering device 1. The transmission varying device 10 is controlled by a controller 11 to which signals from a car speed sensor 12 and a handle steering angle sensor 13 are inputted. Namely, the controller 11 sets a transmission ratio according to a detecting car speed and computes a wheel steering angle from the transmission ratio and a handle steering angle, and controls the transmission ratio varying device 10 according to the computing result. In this case, when it is detected that a vehicle is in a transient state, e.g. acceleration, deceleration, control is effected so that the transmission ratio is fixed to a value prevailing right before a transient state.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a steering device for an automobile, particularly a vehicle speed-sensitive steering device that changes the transmission ratio between the steering wheel angle and the wheel steering angle according to the vehicle speed. Regarding improvements.

(Prior Art) In general, a steering device for an automobile displaces a tie rod in the lateral direction via a steering gear device such as a rack and pinion by rotating a steering handle. However, the transmission ratio between the rotation angle of the steering handle (handle steering angle) and the turning angle of the wheels (wheel steering angle) is set constant. is customary.

However, for example, when the vehicle is running at high speeds, the transmission ratio (handle steering angle/axle steering angle) is increased to improve driving stability, and when the vehicle is running at low speeds, the behavior of the vehicle is made agile to provide a good driving feeling. It is desirable to improve maneuverability by lowering the transmission ratio from the viewpoint of increasing the vehicle's efficiency and making it easier to park the vehicle in a garage.

To meet these demands, for example, Japanese Patent Application Laid-Open No. 58-224852 proposes a vehicle speed-sensitive steering device that changes the transmission ratio between the steering wheel angle and the wheel steering angle according to the vehicle speed. has been done.

By the way, in the vehicle speed-sensitive steering device as described above, when the transmission ratio is changed during a transient state of the vehicle speed, that is, during acceleration/deceleration, the transmission ratio becomes higher during acceleration (the wheels are less likely to break). Changing the steering wheel angle causes a tendency to oversteer, and during deceleration (when braking or off the accelerator) the transmission ratio becomes lower (the wheels tend to turn), so changing the steering wheel angle causes
There was a problem that so-called entrainment (wheels breaking more than expected) occurred.

(Object of the Invention) The present invention has been made to solve the above-mentioned problems, and its purpose is to prevent oversteer and entanglement in the transient state of the vehicle.

(Structure of the Invention) Therefore, the present invention has the following features, as shown in FIG.
A transmission pressure variable means for changing the transmission ratio between the steering wheel angle and the wheel steering angle in accordance with the output signal of the vehicle speed sensor C is interposed in the steering force transmission path for steering the wheels B in accordance with the steering of the steering wheel A. The present invention is a steering device for a motor vehicle, characterized in that it is provided with a control means E for fixing the transmission ratio when a transient state of the vehicle is detected.

(Effects of the Invention) According to the present invention, in the vehicle speed-sensitive variable transmission ratio steering device, the control means fixes the transmission ratio when a transient state of the vehicle is detected. The transmission ratio is fixed, which means that the steering angle can be changed just before acceleration, which prevents oversteer and provides good running stability, while the transmission ratio is fixed even during deceleration. In other words, since the steering angle can be changed just before deceleration, so-called entanglement can be prevented from occurring and driving stability can be improved.

(Embodiments) Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

As shown in FIG. 2, the steering device 1 includes a steering wheel 2, and a steering wheel shaft 3 that rotates the steering wheel 2.
and a steering gear device 5 inputted via the intermediate shaft 4, and left and right steering wheels 6. by the output of the gear device 5.
The link mechanism 9 includes a pitman arm 7, a tie rod 8, etc. that steers the steering wheel 6.

Between the steering wheel shaft 3 and the intermediate shaft 4, there is a rotation angle of the steering handle 2 (handle steering angle: θh) and a wheel 6.
6 steering angle (wheel steering angle: 0w) (transmission ratio: R = θh
/θW) variable transmission pressure device i.

is provided.

A controller 11 is provided to control the variable transmission pressure device 10, and the controller 11 receives a signal S1 indicating the vehicle speed from a vehicle speed sensor 12 that detects the vehicle speed of the vehicle, and a steering angle of the steering wheel 2. θh
A signal S from a steering wheel angle sensor 13 that detects the steering angle is inputted.

As shown in detail in FIGS. 3 to 5, the transmission pressure variable device 10 has an input shaft 14 disposed on the same axis as the intermediate shaft 4 and facing the handle. Axis 3
rotation is inputted through a pair of input gears 15 and 16.

A planetary gear mechanism 17 is interposed between the input shaft 14 and the intermediate shaft 4, and the planetary gear mechanism 17 includes a sun gear 18 fixed on the input shaft 14, and a sun gear 18 fixed on the input shaft 14.
A plurality of pinion gears 19...19 arranged above,
A ring gear 20 is disposed outside of these pinion gears 19...19 and is fixed to the intermediate shaft 4, and is fitted and supported on the input shaft 14 so as to be relatively rotatable, and drives the pinion shafts 21...21. Through each of the above pinion gears 19
. . 19 and a carrier 22 supporting the carriers 19.

A sector gear 23 is integrally provided on the carrier 22, and a pinion gear 25 fixed to a rotating shaft 24a of a stepping motor 24 is meshed with the sector gear 23.

When the steering wheel 2 is turned, the stepping motor 24 is rotationally driven in accordance with the drive signal S from the controller 11, so that in the planetary gear mechanism 17, the sun gear 18 is rotated by an amount corresponding to the steering wheel steering angle θh. At the same time as the carrier 22 is rotated, the carrier 22 is rotated in accordance with the rotation of the stepping motor 24, and thereby the ring gear 20 or the intermediate shaft 4 corresponding to the wheel steering angle θW is rotated.
The amount of rotation is increased or decreased, and the transmission ratio R of the steering wheel angle θh to the wheel steering angle θW is variably controlled.

On the other hand, the controller 11 that variably controls the transmission ratio as described above is connected to the vehicle speed sensor 12 as shown in FIG.
and a control amount calculation section 26 into which the signal SI from the steering wheel angle sensor 13 and the signal S2 from the steering wheel angle sensor 13 are input, and the calculation section 26
The signal S3 outputted from the signal generating section 27 is used as a driving signal to drive the stepping motor 2.
4, the amount of rotation of the motor 24 is detected by a motor rotation angle sensor 28, and is fed back to the drive signal generator 27 as a feedback signal S4.

Here, the control amount calculation unit 26 sets the transmission ratio R of the steering wheel steering angle to the wheel steering angle θ according to the vehicle speed V indicated by the signal S from the vehicle speed sensor 12 based on a predetermined characteristic. In addition, this transmission ratio R and the above-mentioned steering wheel steering angle θ
A wheel steering angle θ1 is calculated from the wheel steering angle θ1, and a drive signal S is output to the stepping motor 24 via the drive signal generator 27 so that the wheel steering angle θW is obtained.

In this case, the characteristics of the transmission ratio R with respect to the vehicle speed V are set such that the transmission ratio R increases as the vehicle speed V increases (see FIG. 7).

As a result, when driving at high speeds, the transmission ratio R becomes high and the wheels 6 are difficult to break, so good running stability is obtained.At the same time, when driving at low speeds, the transmission ratio R becomes low and the wheels 6 are easy to break, so the garage Maneuverability will be improved, such as easier insertion.

Therefore, in addition to the above configuration, the controller 11 is provided with a transient state determining section 31.

Then, when this transient state determining section 31 detects acceleration or deceleration based on the amount of depression of the accelerator pedal or brake pedal, or a signal from vehicle speed data, the control amount calculation section 26 stores and stores the information in the control amount calculation section 26. A non-drive signal S3° is applied to the stepping motor 24 to fix the transmission ratio R (data) of the transmission ratio map as shown in FIG. 7 to the transmission ratio R before acceleration/deceleration.

Specifically, as shown in FIG. 8(a), when the transient state determining unit 31 determines that acceleration is in progress based on the amount of depression of the accelerator pedal, the control amount calculating unit 26 determines the Regardless of the transmission ratio map, fix the transmission ratio to R immediately before acceleration,
The stepping motor 24 is controlled to be non-driving using a non-driving signal S3° based on this data.

As a result, the transmission ratio R is fixed during acceleration (transient), that is, the steering angle can be changed just before acceleration, so oversteer can be prevented.

On the other hand, as shown in FIG. 8(b), when the transient state determining section 31 determines that deceleration is occurring based on the amount of depression of the brake pedal, the control amount calculating section 26 calculates the transmission ratio map shown in FIG. Regardless, the stepping motor 2 is fixed to the transmission ratio R immediately before deceleration, and the non-drive signal Ss' based on this data is used to control the stepping motor 2.
4 is controlled in a non-driving manner.

As a result, the transmission ratio R is fixed during deceleration (transient), that is, the steering wheel angle can be changed as if just before deceleration, so it is possible to prevent entanglement.

[Brief explanation of drawings]

Fig. 1 is a configuration diagram of the present invention, Fig. 2 is a perspective view of the steering device, Fig. 3 is an enlarged longitudinal sectional side view of the variable transmission pressure device, Fig. 4 is a sectional view taken along line I-I in Fig. 3, Figure 5 shows ■− in Figure 3.
■ Line sectional view, Figure 6 is a block diagram showing the configuration of the controller, Figure 7 is a characteristic diagram of control by the controller, and Figure 8 is a block diagram showing the configuration of the controller.
Figure (a) is a graph showing a fixed transmission ratio state during acceleration.
Figure (b) is a graph showing a fixed transmission ratio state during deceleration. l... Steering device, 2... Steering handle (A), 6... Wheels (B), lO... Transmission pressure variable means (D), 11... Controller, 12... Vehicle speed sensor (C), 13... Steering wheel steering angle sensor, 26
...Controlled amount calculation unit (E: control means), 31...Transient state determination unit, θh...Handle wheel steering angle, θW...Wheel steering angle, R...Transmission ratio, ■... Vehicle speed.

Claims (1)

[Claims] (1) A transmission ratio variable means that changes the transmission ratio between the steering wheel angle and the wheel steering angle in accordance with the output signal of the vehicle speed sensor is interposed in the steering force transmission path that turns the wheels in accordance with the steering of the steering wheel. 1. A steering device for an automobile, characterized in that the steering device is provided with a control means for fixing a transmission ratio when a transient state of the vehicle is detected.