JPS6220757A - Steering device for car - Google Patents

Abstract

PURPOSE:To obtain good steering characteristics optimum for a driver's demand and choice by setting a plurality of kinds of transmission ratio characteristics for a wheel steering angle to a steering handle angle, and selecting one kind of characteristics therefrom. CONSTITUTION:A variable means 9 for a transmission ratio is provided in way of a steering power transmission circuit in order to change a transmission ratio of a wheel steering angle thetaW to a steering handle angle thetaH, comprising planetary gears, differential gears and a step motor for the control thereof. And said means 9 is controlled by a control signal from a controller 33 to change a transmission ratio of a wheel steering angle to a steering handle angle. At this time, a plurality of kinds of the transmission ratio characteristics which are set by a setting device for the characteristics of a controller transmission ratio, is changed over by a changeover means and one of the characteristics is used for the control of the transmission ratio. Consequently, a driver can choose desired characteristics for the transmission ratio and obtain steering characteristics optimum for his demand and choice.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a steering device that can change the transmission ratio (reduction ratio) of a wheel steering angle to a steering wheel steering angle of an automobile.

(Prior Art) In general, a steering device for an automobile converts the rotational movement of a steering wheel into a lateral displacement movement of a tie rod through a steering gear device such as a rack-and-nion steering wheel, which is connected to both ends of the tie rod. The direction of the left and right steering wheels is changed by changing the rotation m of the steering wheel (steering wheel angle) and the turning angle of the wheels (
111 wheel steering angle) is normally always maintained in a constant correspondence relationship. However, for example, when a car is running at high speed, it is desirable to increase the transmission ratio of the wheel steering angle to the above-mentioned steering wheel steering angle and to reduce the size of the wheel steering angle with respect to a constant steering wheel steering angle, in order to ensure driving stability. When driving at low speeds, the above transmission ratio is conversely reduced and the wheel rudder is adjusted to a constant steering angle in order to make the car's behavior more agile and provide a good driving feeling, or to make it easier to park the car in the garage. It is desirable to increase the angle.

Therefore, in order to meet such requirements, as disclosed in Japanese Patent Application Laid-open No. 58-224852, for example,
A speed-sensitive steering device has been proposed that changes the transmission ratio of the wheel steering angle to the steering wheel steering angle in accordance with the vehicle speed of the automobile. A transmission mechanism is installed between the steering handle and the steering column, consisting of a pair of opposing variable pitch pulleys and a V-belt wrapped between both pulleys, and the pitch diameter of the driven pulley is adjusted to the vehicle speed. It is controlled by a stepping motor so that it becomes larger as the value increases. According to this, the rotation transmission ratio from the steering wheel to the steering column increases when the vehicle speed is high, and as a result, the turning angle of the wheels relative to a constant steering wheel steering angle becomes small at high speeds and large at low speeds, and as the vehicle speed increases. Corresponding good steering characteristics can be obtained.

(Problem to be Solved by the Invention) By the way, when the transmission ratio of the steering wheel angle to the steering wheel angle is variably controlled in accordance with the vehicle speed, it is common to set the characteristics of the transmission ratio constant. However, it is difficult to always properly match the set transmission ratio characteristics to the preferences of various drivers. It is desirable to keep it.

The present invention has been made in view of the above points, and an object of the present invention is to set a plurality of types of transmission ratio characteristics of the wheel steering angle with respect to the above-mentioned steering wheel steering angle, thereby improving the transmission ratio characteristics of the plurality of types. The object of the present invention is to enable one characteristic to be selected from among them, so that good steering characteristics matching the driver's needs and preferences can be obtained.

(Means for Solving the Problems) In order to achieve the above object, the solving means of the present invention provides a steering wheel steering wheel in a steering force transmission path that transmits the steering force of the steering wheel to the wheels via the steering gear device. A transmission ratio variable means is provided for changing the transmission ratio of the wheel steering angle to the wheel steering angle. This transmission ratio variable means is comprised of, for example, a *U gear mechanism or a differential gear mechanism, and an actuator such as a stepping motor that controls the operation of the gear mechanism. Further, a controller is provided for outputting a control signal to the transmission ratio variable means, and the controller is provided with a transmission ratio characteristic setting section for setting a plurality of types of G transmission ratio characteristics for the transmission ratio variable means. Further, the configuration includes a switching means for switching between a plurality of types of transmission ratio characteristics set by the transmission ratio characteristic setting section.

(Function) Therefore, in the present invention, with the above configuration, when the steering wheel is steered to turn the wheels, the transmission ratio variable means is actuated and controlled by the control signal output from the controller as the steering wheel is steered. The transmission ratio of the wheel steering angle to the steering wheel steering angle is variably controlled. At this time, a plurality of types of transmission ratio characteristics that are variably controlled by the transmission ratio variable means are set in the transmission ratio characteristic setting section of the controller, and the plurality of types of transmission ratio characteristics are switched by the switching means. The transmission ratio of the transmission ratio variable means is controlled based on one of the characteristics. Therefore, if the driver operates the above-mentioned switching means, it is possible to select the transmission ratio characteristic according to the driver's preference, and as a result, the steering characteristic matching the driver's requirements and preferences can be obtained. It is.

(Example) Embodiments of the present invention will be described below based on the drawings.

FIG. 1 shows the overall configuration of an embodiment of the present invention, where 1 is a steering handle to which one end of a handle shaft 2 is fixed, and 3 is a steering handle connected to the other end of the handle shaft 2 via an intermediate shaft 4. At the same time, pitman arm 5. tie rod 6
The steering gear device is connected to the left and right steering wheels 8.8 via a link device 4II17 consisting of a steering wheel 8.8, and a steering wheel steering angle is connected to the steering wheel 8.8 in the middle of the steering force transmission path between the steering wheel 1 and the steering gear device 3. A transmission ratio variable means 9 is provided for changing the transmission ratio R of the wheel steering angle θW with respect to θH.

The transmission ratio variable means 9 includes 1. As shown in enlarged detail in FIGS. 2 to 4, an input gear 10. an input shaft 12 drive-coupled via 11, and an input shaft 12 and intermediate shaft 4;
and a planetary gear mechanism 13 disposed between.

The planetary tooth IN mechanism 13 has a sun gear 14 fixed to the input shaft 12, a ring gear 15 fixed to the intermediate shaft 4, and meshes between the two gears 14 and 15, respectively, with the two gears 14 and 15. For example 3 arranged at angular intervals
planetary pinions 16.16, . . . and the pinions 16.16. ... are the pinion shafts 17, 17.・・・
and a pinion carrier 18 which is carried through the input shaft 12 and externally fitted rotatably on the input shaft 12. Further, a sector gear 19 is formed in the above and the nion carrier 18, and a pinion 21 fixed to the rotating shaft 20a of the stepping motor 20 is meshed with one of the sector gears. The planetary pinions 16.16, . . By controlling the amount of rotation from the steering wheel shaft 2 or sun gear 14 to the ring gear 15 and the intermediate shaft 4 by the rolling of..., the steering wheel steering angle θ is
It is configured to change the transmission ratio R of the wheel steering angle θW with respect to H.

On the other hand, 33 is a controller comprising a computer that outputs a control signal to the transmission ratio variable means 9 to control the operation of the stepping motor 20;
3 is the steering wheel angle θH of the steering wheel 1.
The steering wheel angle sensor that detects the current 30 and the vehicle speed■
Each output signal from a vehicle speed sensor 31 that detects the vehicle speed is input.

As shown in detail in FIG. 5, the controller 33 converts the steering wheel angle θH and vehicle speed V detected by the steering wheel angle sensor 30 and the vehicle speed sensor 31, respectively, to the vehicle speed stored in the characteristic storage unit 35 in advance. A target transmission ratio calculating section 37 that calculates a target transmission ratio R' to be controlled by the transmission ratio changing means 9 by collating and comparing one type of transmission ratio characteristic map I; The transmission ratio R' is multiplied by a predetermined coefficient Ke to obtain the transmission ratio R'
A correction section 39 corrects the target transmission ratio R (-R'
and a motor drive unit 38 that drives the stepping motor 20 so that the actual rotation angle of the stepping motor 20 detected by the above-mentioned rotation angle matches the rotation angle corresponding to the calculated target transmission ratio R.

The correction section 39 receives an output signal from a changeover switch 41 which is provided in addition to the controller 33 and switches a coefficient Ke used by the correction section 39 to correct the target steering ratio R'. When the driver operates this changeover switch 41, the value of the corrected final target transmission ratio R is set.

Here, the procedure of signal processing performed in the controller 33 will be further explained with reference to the flowchart shown in FIG. First, in the first step S1, the steering wheel steering angle θH and the vehicle speed V detected by the steering wheel steering angle sensor 30 and the vehicle speed sensor 31 are read, and in the next step S2, the read vehicle speed V is stored in the characteristic storage section 35.
The target transmission ratio R' for the vehicle speed V is read by comparing it with the characteristic map of , and the data of the changeover switch 41 manually operated by the driver is read in step S3. Then, in step S4, a predetermined coefficient corresponding to the data of the changeover switch 41 read above) (
After determining e, the coefficient Ke is multiplied by the read target transmission ratio R' in step Ss to calculate the final target transmission ratio R-R'X)(e, and then in step S6
The stepping motor 20 (actuator) of the transmission ratio variable means 9 is driven so that the calculated target transmission ratio R is achieved.

Therefore, the target transmission ratio calculation section 37, characteristic storage section 35, and correction section 39 in the above-mentioned COSIDRO 533 change the transmission ratio characteristic in the transmission ratio variable means 9 to the transmission ratio as the vehicle speed V increases, as shown in FIG. The rate of increase in R (gear ratio) is
A transmission ratio characteristic setting unit 40 is configured to set three types of characteristics in descending order of size: ``sporty,''``normal,'' and ``mild.'' Further, the transmission ratio characteristic setting section 40
The changeover switch 41 is configured to switch between three types of transmission ratio characteristics set by the above.

Therefore, in the above embodiment, while the car is running,
When the steering wheel 1 is steered, the movement is transmitted via the steering wheel shaft 2 to the input shaft 12 of the transmission ratio variable means 9.
The sun gear 14 of the planetary gear mechanism 13 rotates. Further, the steering wheel steering angle θH that changes with the steering of the steering wheel 1 is detected by the steering wheel steering angle sensor 30, and the vehicle speed V at that time is detected by the vehicle speed sensor 31. Upon receiving the signal, the controller 33 outputs a control signal to the stepping motor 20 of the transmission ratio variable means 9, and the motor 2
0ff-rotation control is performed, and the rotation of the motor 20 rotationally drives the binion carrier 18 in the planetary gear mechanism 13 via the binion 21 and sector gear 19.

That is, in the transmission ratio variable means 9, the sun gear 14 is rotated by an angle proportional to the steering angle θH of the handle 1, and at the same time, the binion carrier 18 is rotated according to the rotation angle of the stepping motor 20 controlled by the controller 33. Become so. Therefore, the ring gear 15 of the transmission ratio variable means 9 and the intermediate shaft 4 integrated therewith rotate by an angle that increases or decreases the rotation angle of the binion carrier 18 with respect to the steering angle θH, and the rotation of the intermediate shaft 4 As a result, the wheels 8, 8 are steered, and as a result, the transmission ratio R of the wheel steering angle θW to the steering wheel steering angle θH is variably controlled in accordance with the vehicle speed V.

In that case, in the controller 33, the target transmission ratio calculation section 37 calculates the target transmission ratio R' based on the vehicle speed V and the steering wheel angle θH, and the correction section 39 calculates the target transmission ratio R' at the changeover switch 41. The output is corrected to the final target transmission ratio R-R' xKe by the output from
The transmission ratio variable means 9 so as to achieve this final target transmission ratio R
The operation is controlled. Therefore, when the driver operates the changeover switch 41, the characteristics of the transmission ratio R with respect to the vehicle speed V can be set to "sporty,""normal," or "mild."
You can select from three types of characteristics: ``Normal'', which is the normal steering characteristic, and ``Sporty'', where the rate of increase in the transmission ratio R with respect to the increase in vehicle speed V is small.
When switching to , the transmission ratio R of the wheel turning angle θW to the steering wheel steering angle θH can be kept small overall to make the movement of the car more agile. When switching to "mild", which has a large ratio, the transmission ratio R of the wheel steering angle θW to the steering wheel steering angle θH can be kept relatively large, and the movement of the car can be made gentler. It is possible to obtain matching steering characteristics.

In the above embodiment, three types of transmission ratio characteristics are set by correcting one type of transmission ratio characteristic stored in advance by multiplying it by the coefficient Ke switched by the changeover switch 41. Three types of transmission ratio characteristics may be set and stored in advance, and one of them may be selected by the switching means, and the same effects as in the above embodiment can be achieved.

(Effects of the Invention) As described above, according to the present invention, there is provided a steering device for an automobile in which the transmission ratio of the wheel steering angle to the steering wheel steering angle is changed by the transmission ratio variable means, in which a plurality of types of transmission ratio characteristics are provided. By setting multiple types of transmission ratio characteristics and switching between them using a switching means operated by the driver, the transmission ratio characteristics can be freely selected according to the driver's preference, and the transmission ratio characteristics can be changed according to the driver's needs. This has an excellent practical effect of being able to obtain steering characteristics.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, and FIG. 1 is a perspective view showing the overall structure of the steering device, FIG. 2 is a sectional view showing the structure of the transmission ratio variable means, and FIGS.
5 is a block diagram showing the configuration of the controller, FIG. 6 is a flowchart showing the routine processed by the controller, and FIG.
The figure is an explanatory diagram illustrating a plurality of types of transmission ratio characteristics. DESCRIPTION OF SYMBOLS 1... Steering handle, 3... Steering gear device, 8... Wheels, 9... Transmission ratio variable means, 1
3... Planetary gear mechanism, 20... Stepping motor, 30... Steering wheel steering angle sensor, 31... Vehicle speed sensor, 33... Controller, 39... Correction unit, 40
... Transfer characteristic setting section, 41... Selector switch.

Claims (1)

[Claims] (1) A transmission ratio variable means that is provided in a steering force transmission path that transmits the steering force of the steering wheel to the wheels via the steering gear device, and that changes the transmission ratio of the wheel steering angle to the steering wheel steering angle, and the transmission ratio a controller for outputting a control signal to the variable means, the controller is provided with a transmission ratio characteristic setting section for setting a plurality of types of transmission ratio characteristics in the transmission ratio variable means; What is claimed is: 1. A steering device for an automobile, comprising a switching means for switching between a plurality of types of transmission ratio characteristics.