JPS6094869A - Four-wheel steering device for vehicle - Google Patents

Abstract

PURPOSE:To prevent a dead angle from occurring as well as to improve drivability, by making a mirror angle adjustable according to either of antiphase mode or an isophase mode in a sense of backward rotation to front wheels. CONSTITUTION:A mirror driving device 7b driven by a mirror controller 7a is constituted of a mirror motor 37 consisting of a small-sized shaft end of the mirror motor 37, a spur gear 39 engaged with this worm gear and a mirror support device 40 tightly installed in this spur gear 39. Each output of a front wheel steering angle sensor 3, a speed sensor 11, a rear wheel turn-steering angle sensor 12 is processed at a rear wheel controller 4a and outputted to both of a rear wheel turn-steering drive circuit 4b and the mirror controller 7a. This controller 7a adjusts a mirror angle in conformity with the mode of a selector switch 6 by means of a signal out of the controller 4a and solves a problem on a dead angle in time of driving.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a four-wheel steering system for a vehicle, and particularly to a mirror adjustment means that operates in conjunction with a rear wheel weight control means.

2. Description of the Related Art Conventionally, a so-called remote control mirror is known in which the mirror angle can be remotely controlled up, down, left, right, or diagonally in order to make it easier to see the target field from the driver's position.

In addition to the above, as described in Japanese Utility Model Application Publication No. 57-101641, there is a light sensor on the mirror that operates by sensing light from the rear of the vehicle, and a light sensor that receives a light sensitive signal from the light sensor to prevent the mirror from operating. 2. Description of the Related Art An anti-glare mirror device for a vehicle is known which is provided with a drive device that switches to a dazzling state.

In addition, as described in Japanese Utility Model Application Publication No. 58-29540, the remote control mirror is rotated for a certain period of time in conjunction with turn signal operation when entering a highway, changing lanes, parking, or pulling over. A remote control mirror device that changes dynamically is known.

However, by steering the rear wheels in conjunction with front wheel steering, it is possible to turn with a small turning radius when turning at low speeds (forward or reverse), to quickly steer when changing lanes, and to avoid parallel parking. A vehicle equipped with a four-wheel steering system has a unique problem that cannot be solved simply by applying the conventional remote control mirror device described above.

In other words, in a four-wheel steering vehicle, when turning, the rear wheels are placed in a reverse phase mode (the front and rear wheels are directed in opposite directions) relative to the front wheels.
On the other hand, when changing lanes or parallel parking, ° controls the rear wheels in the same phase mode as the front wheels (the front and rear wheels have an opening force of 1iil).
It is necessary to control the

Therefore, depending on whether the vehicle is in the opposite phase mode or the same phase mode, especially during hack driving, the field of view of the mirror facing the direction of travel of the vehicle will be in completely opposite directions.

For example, when driving in a bank by steering the steering wheel clockwise, in reverse phase mode the vehicle will turn towards the rear right, whereas in same phase mode the vehicle will go straight towards the rear left. Therefore, it is not possible to achieve the objective simply by controlling the mirror angle in correspondence with the turning operation of the steering wheel as in a front wheel steering vehicle.(Object of the Invention) The present invention aims to solve the above problem. It is an object of the present invention to provide a four-wheel steering system for a vehicle, which is equipped with a mirror adjustment means that allows the mirror angle to be adjusted appropriately depending on whether the orientation of the rear wheels with respect to the front wheels is in the opposite phase mode or the same phase mode. shall be.

(Structure of the Invention) A four-wheel steering device for a vehicle according to the present invention, as shown in the overall configuration diagram of FIG. an angle detection means 3; a rear wheel control means 4 which receives a detection signal from at least the front wheel steering angle detection means 3 and outputs a rear wheel steering drive signal; and a rear wheel control means 4 which receives a rear wheel steering drive signal from the rear wheel control means 4; In a four-wheel steering system for a vehicle comprising a rear wheel steering means 5 for steering rear wheels 9, switching is made between an in-phase mode in which the rear wheels 9 face in the same direction with respect to the front wheels 8, and an anti-phase mode in which the rear wheels 9 face in the opposite direction. A changeover switch 6 is provided on the rear wheel control means 4, and a mirror angle adjustment means 7 is provided for changing the angle of the mirror in accordance with the mode changeover of the changeover switch 6.

(Effects of the Invention) Since the present invention is configured as described above, the mirror angle is automatically adjusted appropriately according to the in-phase mode and the anti-phase mode which are selected and switched with the changeover switch, thereby making it possible to particularly improve hack driving. At the same time, it is possible to reliably grasp the target field of view in the direction of travel of the vehicle using the mirror, prevent the occurrence of a dead area, and improve the tiittability.

At the same time, since the direction of the mirror indicates the direction of travel of the vehicle, the driver can confirm the direction of travel of the vehicle simply by checking the direction of the mirror.

(Example) Embodiments of the present invention will be described below with reference to the drawings.

As shown in FIG. 2, this four-wheel steering device includes a front wheel steering device l, a front wheel steering angle sensor 3, a vehicle speed sensor 11, a rear wheel control controller 4a, a steering/knobbing motor driver 4b, and a rear wheel steering device 5, and rear wheel steering angle sensor 1
2, an AUTO/CRAB changeover switch 6, a mirror controller 7a, a mirror drive device 7b that changes the angle of the mirror 10, a mirror angle detector 7C, a meter display 13, and the like. However, reference numeral 14 is a terminal connected to the battery, and reference numeral 15 is a terminal connected to the ignition switch circuit.

The front wheel steering device 1 is of a normal rank-binion type, in which the lower end of the steering wheel 2 is engaged with the rack of the front wheel operating rod 16, and each of the left and right ends of the front wheel operating rod 16 is connected to a tie rod 17. The front wheel 8 is connected to the knuckle arm 18 via the knuckle arm 18, and the front wheel 8 is rotatably supported on the shaft portion of the knuckle arm 18. By rotating the steering wheel 2, the front wheel operating rod 16 is driven in the axial direction via the rank-binion mechanism,
A knuckle arm 18 is swung around a king pin 19 via a tie rod 17, thereby steering a pair of left and right front wheels 8. However, the front wheel steering device 1 is of the above rank.
It goes without saying that a mechanism other than the vinyl length type would be fine.

The front wheel steering angle sensor 3 for detecting the front wheel steering angle of the front wheel steering device 1 detects the rotation angle of the steering wheel shaft using, for example, an electromagnetic pickup sensor, and outputs the detection signal to the rear wheel control controller 4a. .

The vehicle speed sensor 11 is similarly an electromagnetic big amplifier type sensor, which detects the rotational speed of the main drive shaft, and outputs the detection signal to the rear wheel controller 4a.

The rear wheel steering device 5 includes a rear wheel operating rod 20 slidably supported on the vehicle body, a knuckle arm 22 connected to each left and right end of the rear wheel operating rod 20 via a tie rod 21, A power cylinder 2 with a rear wheel power steering link tJll structure that drives a rear wheel operating rod 20 in the axial direction.
3, an oil pump 24 that supplies pressure oil to the power cylinder 23, a low-return valve 25 as a control valve for switching the oil path from the oil pump 24 to the power cylinder 23, and a pinion shaft connected to the rotor of the low-return valve 25. 2G, a stepping motor 28 that drives the rotary valve 25 via a pinion shaft 26 and a pair of bevel gears 27, and a pinion 29 of the pinion shaft 26.
The rack 30 of the rear wheel operating rod 20 is formed to mesh with the rear wheel operating rod 20.

A piston 31 in the power cylinder 23 is fixed to the rear wheel operating rod 20, and hydraulic oil chambers 32'a and 32b are defined on both sides of the piston 31 in the power cylinder 23.
Oil passages 33a and 33b are respectively introduced from the rotary valve 25 to the rotary valve 25, and an oil supply passage 34 from the oil pump 24 to the rotary valve 25 and an oil drain passage 35 from the rotary valve 25 to the oil pump 24 are also introduced.

The above rank/binion mechanism! 29 and 30, the rear wheel operating rod 20 can be moved in the axial direction according to the direction and amount of rotation of the stepping motor 28, and the rotary valve 25 functions as a torsion bar when the stepping motor 28 rotates. pinion shaft 26
, the pressure oil supplied from the oil supply path 34 is introduced into one of the hydraulic oil chambers 32a and 32b of the power cylinder 23 according to the direction and magnitude of the rotational force, and the other is switched according to the applied rotational force. The pressure oil in the hydraulic oil chambers 32a, 3'2b is not returned to the υ1ura path 35.

That is, when the stepping motor 28 drives the rear wheel operating rod 2o in the axial direction via the pair of bevel gears 27, the pinion shaft 26, and the rank and pinion mechanisms 29 and 30, the rear wheel operating rod 2o is driven by the power cylinder 23. The hydraulic pressure acting on the piston 31 strongly urges the piston 31 in the same direction.

In this way, the rear wheel operating rod 2 with a power steering mechanism operates according to the direction and amount of rotation of the stepping motor 28.
The left and right rear wheels 9 can be steered by swinging the knuckle arm 22 around the king pin 36 via the tie rod 21 and the rear wheels 9.

The rear wheel turning angle sensor 12 is, for example, an electromagnetic pickup type sensor, and detects the rotation of the output shaft of the stepping motor 28, and outputs the detection signal to the rear wheel control controller 1-roller 4a.

The control mode changeover switch 6 is connected to the rear wheel control controller 4a, and manually selects between an in-phase mode in which the rear wheels 9 face in the same direction with respect to the front wheels 8 and an anti-phase mode in which they face in the opposite direction. This is a switch that changes to

The meter display 13 has a display that displays the directions of the front wheels 8 and rear wheels 9 so that it can be visually confirmed whether the mode is the same phase mode or the opposite phase mode.

The mirror drive device 7b driven by the mirror control controller 7a includes a mirror motor 37 consisting of a small stepping motor, a worm gear 38 at the end of the output shaft of the mirror motor 37, a spur gear 39 meshing with the worm gear 38, and a spur gear 39 meshing with the worm gear 38. A mirror support 40 is fixed to the gear 39 and supports the mirror 10. The mirror 10 can be rotated and its direction can be changed according to the direction and amount of rotation of the mirror motor 37 via a speed reduction mechanism consisting of the worm gear 38 and spur gear 39.

The mirror 10 is swung around a vertical axis or an axis slightly tilted backwards from the vertical axis, and the direction in which the mirror 10 is directed is set to the in-phase mode (the front and rear wheels are the same) when driving in a bank, as shown in Figure 3. The mirror control controller 7a directs the vehicle to move backward depending on whether the vehicle is in a reverse phase mode (a state where the front and rear wheels are facing in opposite directions) or a reverse phase mode (a state where the front and rear wheels are facing in opposite directions).

In other words, when retreating in antiphase mode, as shown in Fig. 3(a)
When the steering wheel 2 is operated clockwise as shown in the figure, the vehicle draws an arc and heads to the right rear, so the mirror 10 is rotated slightly to give a wide view of the right rear.
Furthermore, when reversing in the same phase mode for parallel parking, when the steering wheel 2 is operated clockwise as shown in FIG. is rotated slightly to give a wide field of view to the rear left.

The mirror angle detector 7C is composed of a transmitter (20 to 40 kllz) whose transmitting coil inductance changes in conjunction with the rotation of the mirror motor 37, and its detection signal is output to the mirror controller 7a, and its frequency and angle are In the conversion circuit 48 (see FIG. 5), the detected rear wheel turning angle θ is converted into a signal of the detected mirror angle θM'l displaced from the reference position when the detected rear wheel turning angle θ is zero (actual rear wheel turning angle).

Although the mirror 10 is a room mirror, not only the room mirror but also left and right fender mirrors can be controlled in the same way.

Especially when turning backward to the left in reverse phase mode,
It is necessary to adjust the angle of the left fender mirror to the left and use this fender mirror to reliably grasp the target field of view on the left rear, and when retreating to the left rear in the same phase mode as shown in Figure 3 (b). The same is true.

On the other hand, when turning backward to the right in reverse phase mode as shown in Figure 3 (a), adjust the angle of the right fender mirror to the right to ensure the right rear target field of view. The same applies when retreating to the right rear in the same phase mode.

When adjusting the angle of the fender mirrors, each fender mirror is moved by two mirror motors so that the left and right fender mirrors can grasp the lower target field of view on the left and right sides, which is the blind spot of the rearview mirror 10. It is desirable to adjust the angle around a vertical axis and a horizontal axis, or around an oblique axis using one motor, and it is desirable that the rearview mirror 10 can also be adjusted around the above two axes.

The mirror drive device 7b may omit the worm gear 38 and the spur gear 39, and may link the mirror support 4o directly to the output shaft of the mirror motor 37.
Instead, ranks may be provided, and the mirror motor 37 may be replaced with a stroke type motor.

Next, regarding the rear wheel control controller 4a, stepping motor driver 4b, AUTO/CRAB switch 6, and mirror control controller 7a,
a'[, (described below) based on the diagram in the figure and the block diagram in FIG.

First, the control mode of this four-wheel steering system will be explained. As a mode for controlling the target rear wheel steering angle θR with respect to the front wheel steering angle θH, r AUT OJ and [CRA 13
There are two types of J. In r A U TOJ, the rear wheels 9 are controlled so that they are in anti-phase mode at low speeds and in the same phase mode at high speeds, and in "CRAB", they are in the same phase mode at both low speeds and high speeds. mode. During normal driving, "rAUTO" is sufficient, but when parallel parking, rAUTOJ cannot handle the situation and rcRABJ is required.

The AUTO/CRAB changeover switch 6 is a switch for manually switching between the control formats rAUTOJ and rCRABJ, and calculates a target rear wheel turning angle OR (hereinafter referred to as rear wheel turning angle θR) in the rear wheel control controller 4a. It is connected to an arithmetic circuit 41 that performs.

FIG. 4 shows the relationship between the front wheel steering angle θH and the rear wheel turning angle θR using the vehicle speed V as a parameter.
In the case of AUTOJ, as shown by the solid line, at low speed (vehicle speed 3
5km/h or less), the relative relationship between the front wheels 8 and rear wheels 9 is in an antiphase mode, and the steering ratio θR/θH is increased as the speed becomes lower, thereby minimizing the turning radius during low-speed turns. On the other hand, at medium to high speeds (vehicle speed 3)
5 km/h or higher), the relative relationship between the front wheels 8 and rear wheels 9 is in the same phase mode, and the front wheel steering angle el (is within a predetermined range (0 to approximately 1
00°), the steering ratio θR10H is large and above that range, the steering ratio θR/θ11 is kept small to 0.
Also, as the speed increases, the steering ratio θR/
By increasing θH, it is possible to quickly change lanes at high speeds.

Front wheel steering angle θH in case of above r CRA I3 J
The relative relationship between and rear wheel steering angle θR is that at low speeds, as shown by the chain line in the figure, it is an in-phase mode in which the polarity of the diagram on the opposite-phase mode side is reversed, and at medium-high speeds, r A U TOJ
This is the same phase mode as in the case of .

The characteristics of the rear wheel steering angle θR with respect to the front wheel steering angle θ11 illustrated in FIG. or reverse phase mode is automatically set depending on the vehicle speed.

In other words, when switching to [ΔU T OJ, it is in anti-phase mode at low speeds and becomes in-phase mode at medium-high speeds,
When switched to rcRABJ, the mode becomes the same phase mode both at low speeds and at medium and high speeds.

As shown in the block diagram of FIG. 5, the rear wheel controller 4a converts the detection signal σ shoulder of the front wheel steering angle sensor 3 into
An A/D converter 3a that performs D conversion, an A/D converter 11a that performs A/D conversion of the detection signal (2) of the vehicle speed sensor 11, and an A/D converter that A/D converts the detection signal of the rear wheel steering angle sensor 12. It consists of a converter 12a, an arithmetic circuit 41 that calculates the rear wheel turning angle θR, a comparator 42, and a correction signal generation circuit 43, each of which is configured and functions as follows.

The arithmetic circuit 41 receives a front wheel steering angle θH signal obtained by A/D converting the detection signal n of the front wheel steering angle sensor 3, and a vehicle speed V signal obtained by A/D converting the detection signal n of the vehicle speed sensor 11. , the switch signal SW selected by the AUTO/CRAB changeover switch 6, calculates the rear wheel steering angle oR having the characteristic shown in FIG. 4, and outputs the signal to the comparator 42, Based on the switch signal SW and the vehicle speed ■, it is determined whether the in-phase mode is the opposite phase mode, and the mode signal MODE is sent to the mirror control controller 7.
It is output to the arithmetic circuit 44 of a.

The comparator 42 receives the signal of the rear wheel turning angle θR and the signal of the detected rear wheel turning angle θb from the rear wheel turning angle sensor 12 via the A/D converter 12a, and compares the magnitude of both, The difference signal (absolute value and sign of the difference) is output to the correction signal generation circuit 43. The correction signal generation circuit 43 receives the above signal and outputs the rotational direction switching signal R and the drive pulse output signal DP to the stamping motor as a correction signal for correcting the difference between the two (OR-○) so that it becomes 0 value. The stepping motor drive circuit 4b receives both signals I2, D and P, and outputs a rear wheel steering drive signal to the stepping motor 28 to drive it.

By such feedhack control, the rear wheel steering device 5 can be driven so that the steering angle of the rear wheels 9 becomes the target rear wheel steering angle θR.

Next, the mirror control controller 7a includes a calculation circuit 44 that calculates a target mirror angle eM1 of the mirror 10, and a comparator 4.
5, a correction signal generation circuit 46, a mirror motor drive circuit 47, a frequency/angle conversion circuit 48, a gate 49 that becomes conductive when the detected rear wheel turning angle θR is O value, and a mirror reference position storage circuit 50. Each of these is constructed and functions as follows.

However, the arithmetic circuit 44, gate 49, and mirror reference position storage circuit 50 are common to the first mirror 10 (room mirror), the second mirror (right fender mirror), and the third mirror (left fender mirror). There is, but below is the first
The mirror 10 will be explained.

The arithmetic circuit 44 receives a mode signal MO from the arithmetic circuit 41 of the rear wheel control controller 4a and the A/D converter 12a, respectively.
Receiving the signals of DE and the detected rear wheel turning angle θR, as well as receiving the signal of the mirror reference position M1 from the mirror reference position storage circuit 50, the calculation is performed according to a predetermined function g preset in the circuit using these data as parameters. Target mirror angle θ
M1 is calculated and its signal is output to comparator 45.

On the other hand, the frequency/angle conversion circuit 48 converts the frequency change of the oscillator into an angular change of the mirror 10 based on the characteristics of the oscillator (mirror angle detector) 7c preset therein, and detects the mirror angle. A signal of θM1 is output.

The comparator 45 receives the target mirror angle eM1 from the arithmetic circuit 44.
In addition to receiving the signal of the detected mirror angle θM1 from the frequency/angle conversion circuit 48, the magnitude of both is compared, and the difference signal (absolute value and sign of the difference) is sent to the correction signal generation circuit. Output to 46.

The correction signal generating circuit 46 receives the signal from the comparator circuit 45 and corrects it so that the difference between the two (θMl - θM'1) becomes O value. iIi Outputs the rotational direction switching signal MR and drive pulse output signal MD as positive signals to the mirror motor drive circuit 47, and the mirror motor drive circuit 47 receives both the above signals MR-MD and outputs a mirror morph drive signal to the mirror motor 37. As a result, the mirror motor 37
is driven, and the detected mirror angle θM1 becomes the target mirror angle θM1
The angle of the mirror 10 is adjusted and controlled so as to match the angle of the mirror 10.

The gate 49 is connected to the A/D of the rear wheel control controller 4a.
A signal of the detected rear wheel turning angle θR is received from the converter 12a, and a signal of the detected mirror angle θM is received from the frequency/angle conversion circuit 48.
When the detected rear wheel turning angle θh receives a signal of 0 value, conduction occurs and the detected mirror angle θM at that time is received.
A signal 'l is output to the mirror reference position storage circuit 50.

The mirror reference position storage circuit 50 receives the signal of the detected mirror angle θMl from the gate 49, stores it in the memory as the mirror reference position M1, and outputs the signal of the mirror reference position M1 to the arithmetic circuit 44.

In this way, through the gate 49, the detected rear wheel steering angle θk
The detected mirror angle θM'l when is O is the mirror reference position M1
Therefore, each driver can adjust the angle of the mirror 10 as appropriate according to his or her own habits and preferences, and can set the mirror reference position M1 for each driver.

In addition, each signal of vehicle speed V, front wheel steering angle OH1 detected rear wheel steering angle θR is input to an AND circuit, and outputted from the AND circuit to gate 49, vehicle speed ■, front wheel steering angle θH, and detected rear wheel steering angle eh are input.
The gate 49 may be made conductive only when all of the values are zero.

In addition, as parameters for calculating the target mirror angle θM1, instead of the target rear wheel steering angle θR and the control mode signal MODE, the front wheel steering angle θH, the vehicle speed ■, and the control mode signal MO
DE may be used, or the front wheel steering angle θH and the target rear wheel steering angle θR may be used.

This is because the rear wheel steering angle θR is calculated using the front wheel steering angle θH and the vehicle speed V as parameters, as illustrated in FIG. This is because the mode is determined.

As mentioned above, with the changeover switch 6, rAUTOJ and rcR are set.
When one of ABJ is selected, the rear wheel control controller 4
The control mode signal MODE is output from the arithmetic circuit 41 of the mirror control controller 7a to the arithmetic circuit 44 of the mirror control controller 7a, and the target mirror is determined in the arithmetic circuit 44 using the control mode signal MODE, the detected rear wheel turning angle θh, and the mirror reference position M1 as parameters. The angle θM1 is calculated, and based on this, the comparator 45, the frequency/angle conversion circuit 48, and the correction signal generation circuit 4
6 and the mirror motor 3 via the mirror motor drive circuit 47.
7, the angle of the mirror lo can be adjusted according to the above parameters.

The above control can be performed both when performing digital control using a microcomputer and the like, and when performing analog control by configuring the rear wheel control controller and mirror control controller with analog circuits.

[Brief explanation of the drawing]

Among the drawings, FIG. 1 is an overall configuration diagram of the present invention, FIGS. 2 to 5 show embodiments of the present invention, FIG. 2 is an overall configuration diagram, FIG. 3 ta+ and FIG. An explanatory diagram to explain the direction in which the mirror should be directed by adjusting the angle when driving in bank in reverse phase mode and same phase mode. Figure 4 shows rear wheel steering relative to the front wheel steering angle set in the rear wheel control controller. A diagram illustrating the characteristics of the angle, Figure 5 is rear wheel control 3
11 and a block diagram of the entire control system for mirror angle control. 1... Front wheel steering means, 2... Steering wheel, 3... Front wheel steering angle detection means (front wheel steering angle sensor),
4... Rear wheel control means, 4a... Rear wheel control controller, 4b... Stebbing motor drive circuit (stepping motor drive circuit), 5... Rear wheel steering means (rear wheel steering device), 6. ...Choice switch, 7...
Mirror opening adjustment means, 7a...Mirror control controller, 7b...Mirror driving device, 7(...Mirror angle detector. Patent applicant: Toyo Kogyo Co., Ltd.

Claims (1)

[Claims] (1) A front wheel steering means including a steering wheel;
a front wheel steering angle detection means for detecting the steering angle of the steering wheel; a rear wheel control means for receiving a detection signal from at least the front wheel steering angle detection means and outputting a rear wheel steering drive signal; In a four-wheel steering system for a vehicle, which includes a rear wheel steering means that receives a rudder drive signal and steers the rear wheels, there are two modes: an in-phase mode in which the rear wheels face in the same direction as the front wheels, and an anti-phase mode in which the rear wheels face in the opposite direction. A four-wheel steering system for a vehicle, characterized in that a changeover switch for changing the mode is provided on the rear wheel control means, and a mirror angle adjustment means is provided for changing the mirror angle in accordance with the mode change of the changeover switch. Device