JPH0433673B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a four-wheel steering system for a vehicle, particularly to a mirror adjustment means that operates in conjunction with a rear wheel 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 Utility Model Publication No. 57-101641, there is a light sensor on the mirror that operates when it senses light from the rear of the vehicle, and a light sensor that receives a photosensitive signal from this 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, when entering a highway or changing lanes, or when parking or pulling over,
2. Description of the Related Art A remote control mirror device is known in which a remote control mirror is rotated for a certain period of time.

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 by simply applying the above-mentioned conventional remote control mirror system.

In other words, in a four-wheel steering vehicle, when turning, the rear wheels are controlled in opposite phase mode (the front and rear wheels are facing in opposite directions), whereas when changing lanes or parallel parking, the front wheels are controlled in opposite phase mode. The rear wheels must be controlled in the same phase mode (front and rear wheels facing in the same direction).

Therefore, depending on whether the vehicle is in the opposite phase mode or the same phase mode, particularly when the vehicle is traveling backwards, the field of view of the mirror facing the direction in which the vehicle is traveling will be in completely opposite directions.

For example, when driving backwards by turning the steering wheel clockwise, in anti-phase mode the vehicle will turn towards the rear right, whereas in same-phase mode the vehicle will turn towards the rear left and go straight ahead. Therefore, simply controlling the mirror angle in correspondence with the turning operation of the steering wheel, as in front-wheel steering vehicles, cannot achieve the objective.

(Object of the Invention) The present invention is intended to solve the above-mentioned problems, and is aimed at solving the above-mentioned problem.
An object of the present invention is to provide a wheel steering device.

(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. Rear wheel steering drive in response to a detection signal from the detection means 3 and at least the front wheel steering angle detection means 3, in accordance with an in-phase mode in which the rear wheels face in the same direction with respect to the front wheels, and an anti-phase mode in which the rear wheels face in the opposite direction with respect to the front wheels. A four-wheel steering system for a vehicle comprising a rear wheel control means 4 that outputs a signal, and a rear wheel steering means 5 that receives a rear wheel steering drive signal from the rear wheel control means 4 and steers the rear wheels. The present invention is characterized in that a rear visibility member angle adjusting means 7 is provided which receives a signal related to the steering direction of the rear wheels from the wheel control means 4 and adjusts the angle of the rear visibility member in the steering direction of the rear wheels. It is something.

(Effects of the Invention) Since the present invention is configured as described above, by providing the rear visibility member angle adjustment means, the angle of the rear visibility member can be adjusted in the steering direction of the rear wheels. When traveling backwards, the target field of view in the direction in which the vehicle is traveling can be reliably captured by the rear visibility member, thereby preventing the occurrence of dead zones and improving maneuverability.

At the same time, since the direction of the rear visibility member indicates the traveling direction of the vehicle, the driver can confirm the traveling direction of the vehicle simply by checking the direction of the rear visibility member.

(Example) Hereinafter, an example of the present invention will be described based on the drawings.

As shown in FIG. 2, this four-wheel steering system includes a front-wheel steering system 1, a front-wheel steering angle sensor 3, a vehicle speed sensor 11, a rear-wheel controller 4a, a stepping motor driver 4b, and a rear-wheel steering system. Device 5
To, the rear wheel steering angle sensor 12, and the AUTO/
It consists of a CRAB changeover switch 6, a mirror control 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, numeral 14 is a terminal connected to the battery, and numeral 15 is a terminal connected to the ignition switch circuit.

The front wheel steering device 1 is of the usual rack and pinion type, in which a pinion at the lower end of the steering wheel 2 is engaged with a rack of a front wheel operating rod 16, and each left and right end 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 above-mentioned rack and pinion mechanism, and the front wheel operating rod 16 is driven in the axial direction via the tie rod 17.
8 is swung around the king pin 19, thereby steering a pair of left and right front wheels 8. However, it goes without saying that the front wheel steering device 1 may be of a mechanism other than the above-mentioned rack and pinion type.

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 type sensor, and transmits the detection signal to the rear wheel control controller 4a.
Output to.

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

The rear wheel steering device 5 includes a rear wheel operating rod 20 that is slidably supported on the vehicle body, a knuckle arm 22 that is connected to the left and right ends of the rear wheel operating rod 20 via tie rods 21, and a rear wheel operating rod 20 that is slidably supported on the vehicle body. To switch the power cylinder 23 of the power steering mechanism for the rear wheels that drives the wheel operating rod 20 in the axial direction, the oil pump 24 that supplies pressure oil to the power cylinder 23, and the oil path from the oil pump 24 to the power cylinder 23. A rotary valve 25 as a control valve, a pinion shaft 26 connected to the rotor of the rotary valve 25, and a pinion shaft 26 connected to the rotor of the rotary valve 25.
6 and a pair of bevel gears 27 to drive the rotary valve 25, and a rack 30 of the rear wheel operating rod 20 formed to mesh with the pinion 29 of the pinion shaft 26.

The piston 31 in the power cylinder 23 is fixed to the rear wheel operating rod 20, and
Oil passages 33a and 33b are led from the rotary valve 25 to hydraulic oil chambers 32a and 32b, respectively, which are partitioned on both sides of the piston 31 in the oil pump 24. An oil drain path 35 is provided from the rotary valve 25 to the oil pump 24.

Through the rack and pinion mechanisms 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.
is switched in response to the rotational force applied to the pinion shaft 26 functioning as a torsion bar when the stepping motor 28 rotates, and the pressure oil supplied from the oil supply path 34 is transferred to the power cylinder 23 in the direction of the rotational force according to the magnitude. One hydraulic oil chamber 32a, 32b
and the other hydraulic oil chamber 32a, 32b.
The pressure oil is returned to the oil drain passage 35.

That is, a stepping motor 28 drives a pair of bevel gears 27, a pinion shaft 26, and a rack and pinion mechanism 2.
When the rear wheel operating rod 20 is driven in the axial direction via the pistons 9 and 30, the rear wheel operating rod 20 is strongly assisted in the same direction by the hydraulic pressure acting on the piston 31 of the power cylinder 23.

In this way, the knuckle arm 22 is swung around the kingpin 36 via the rear wheel operating rod 20 with a power steering mechanism and the tie rod 21 according to the direction and amount of rotation of the stepping motor 28, and the left and right rear wheels 9 are steered. can do.

The rear wheel steering 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 a detection signal to the rear wheel controller 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 as the front wheels 8 and an anti-phase mode in which they face in the opposite direction. This is a switch to switch to.

The meter display 13 displays front wheels 8 and rear wheels 9 so as to visually confirm whether the mode is the same phase mode or the opposite phase mode.
This is a display device that has a display that shows the orientation of the vehicle.

The mirror drive device 7b driven by the mirror 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, and a spur gear 39 meshing with the worm gear 38. A mirror support 40 is fixed to the spur gear 39 and supports the mirror 10. The mirror 10 is rotated in accordance with the rotational direction and rotation amount of the mirror motor 37 via the reduction mechanism consisting of the worm gear 38 and the spur gear 39.
It is now possible to rotate and change its direction.

The mirror 10 is swung around a vertical axis or an axis slightly tilted backwards from the vertical axis,
As shown in Figure 3, the direction in which the mirror 10 is directed depends on whether the vehicle is in the same phase mode (the front and rear wheels are facing in the same direction) or the opposite phase mode (the front and rear wheels are facing in the opposite direction) when traveling backwards. It is controlled by the mirror controller 7a to direct the mirror to the mirror.

That is, when retreating in antiphase mode, the third
When the steering wheel 2 is operated clockwise as shown in Figure a, the vehicle draws an arc and heads to the right rear, so the mirror 10 is rotated slightly to give a wide field of view to the right rear. When reversing in the same phase mode, as shown in FIG. 3b, when the steering wheel 2 is operated clockwise, the vehicle will move approximately straight to the rear left, so the mirror 10 will provide a wide field of view to the rear left. It is rotated slightly so that it can be inserted into the

The mirror angle detector 7c is connected to a mirror motor 37.
It consists of a transmitter (20 to 40 kHz) whose transmitting coil inductance changes in conjunction with the rotation of the transmitter, and its detection signal is output to the mirror controller 7a and detected by its frequency/angle conversion circuit 48 (see Figure 5). It is converted into a signal of the detected mirror angle ΘM'1 displaced from the reference position when the rear wheel steering angle Θ'R (actual rear wheel steering angle) is 0 value.

Although the mirror 10 is a room mirror, it is possible to control not only the room mirror but also the left and right fender mirrors in the same way.

In particular, 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, as shown in Figure 3b. The same is true when moving backward to the left in the same phase mode.

On the other hand, when turning backwards to the right in reverse phase mode as shown in Figure 3a, it is necessary to adjust the angle of the right fender mirror to the right to ensure the right rear target field of view. The same is true when retreating to the right rear in the same phase mode.

When adjusting the angle of the fender mirror above,
In order to be able to use the left and right fender mirrors to grasp the lower target field of view on the left and right sides, which is the blind spot of the rearview mirror 10, each fender mirror is rotated around the vertical axis and horizontal axis using two mirror motors.
It is desirable that the angle of the rearview mirror 10 can be adjusted around the diagonal axes using a motor on the stand, and it is also desirable that the rearview mirror 10 can also be adjusted around the two axes.

The mirror drive device 7b includes a worm gear 38
and the spur gear 39 may be omitted, and the mirror support 40 may be linked directly to the output shaft of the mirror motor 37. Alternatively, a rack may be provided in place of the worm gear 38, and a stroke type motor may be used in place of the mirror motor 37. It's okay.

Next, the rear wheel control controller 4a, stepping motor driver 4b, AUTO/
The CRAB changeover switch 6 and the mirror control controller 7a will be explained in detail based on the diagram in FIG. 4 and the block diagram in FIG.

First, to explain the control modes of this four-wheel steering system, there are two modes, ``AUTO'' and ``CRAB'', to control the target rear wheel steering angle ΘR relative to the front wheel steering angle ΘH. The rear wheels 9 are controlled so that they are in the opposite phase mode at times and in the same phase mode at high speeds, and are controlled to be in the same phase mode at both low speeds and high speeds in "CRAB". "AUTO" during normal operation
However, when parallel parking, select "AUTO".
This is because "CRAB" is required because it cannot be dealt with by using "CRAB".

The AUTO/CRAB changeover switch 6 is a switch for manually switching between the control formats "AUTO" and "CRAB", and is a switch for manually switching between the control formats "AUTO" and "CRAB". ) is connected to an arithmetic circuit 41 that calculates .

Figure 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. ) has front wheel 8
The relative relationship between the front wheels and the rear wheels 9 is in an antiphase mode, and the steering ratio ΘR/ΘH increases as the speed decreases, thereby making it possible to minimize the turning radius when turning at low speeds. At high speed (vehicle speed 35
Km/h or more), the relative relationship between the front wheels 8 and rear wheels 9 is in the same phase mode, and the front wheel steering angle ΘH is within a predetermined range (0
~100°), the steering ratio ΘR/ΘH is large, and above that range, the steering ratio ΘR/ΘH is small to 0.
Furthermore, as the speed increases, the steering ratio ΘR/ΘH is increased within the above-mentioned predetermined range, thereby making it possible to quickly change lanes at high speed.

In the above case of "CRAB", the relative relationship between the front wheel steering angle ΘH and the rear wheel steering angle ΘR is that at low speeds, as shown by the chain line in the figure, it is the same phase mode where the opposite phase mode side graph is reversed in positive and negative. , at medium and high speeds, it is in the same phase mode as in the case of "AUTO".

The characteristics of the rear wheel steering angle ΘR with respect to the front wheel steering angle ΘH illustrated in FIG.
The above is set in advance in the arithmetic circuit 41 of a.
By switching the AUTO/CRAB changeover switch 6, either the same phase mode or the opposite phase mode is automatically set in relation to the vehicle speed.

That is, when switched to "AUTO", the mode is in anti-phase mode at low speeds and in the same phase mode at medium to high speeds, whereas when switched to "CRAB", the mode is in the same phase mode at both low speeds and medium to high speeds.

As shown in the block diagram of FIG. 5, the rear wheel controller 4a includes an A/D converter 3a that converts the detection signal of the front wheel steering angle sensor 3 into an A/D converter;
An A/D converter 11a that A/D converts the detection signal of the vehicle speed sensor 11, and an A/D converter 12a that A/D converts the detection signal of the rear wheel steering angle sensor 12.
and an arithmetic circuit 41 that calculates the rear wheel turning angle ΘR.
It consists of 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 signal of the front wheel steering angle ΘH obtained by A/D conversion of the detection signal of the front wheel steering angle sensor 3, a signal of the vehicle speed V obtained by A/D conversion of the detection signal of the vehicle speed sensor 11, and AUTO/D. In response to the switch signal SW selected by the CRAB changeover switch 6, a rear wheel turning angle ΘR having the characteristics shown in FIG. Based on SW and vehicle speed V, it is determined whether the mode is the same phase mode or the opposite phase mode, and the mode signal MODE is outputted to the arithmetic circuit 44 of the mirror control controller 7a.

The comparator 42 converts the signal of the rear wheel steering angle ΘR and the rear wheel steering angle sensor 12 into an A/D converter 12a.
It receives a signal of the detected rear wheel turning angle ΘR via the controller, compares the magnitude of the two, and outputs a signal of the difference (absolute value and positive/negative sign of the difference) to the correction signal generation circuit 43. Upon receiving the above signal, the correction signal generation circuit 43 outputs the rotational direction switching signal R and the drive pulse output signal DP as correction signals for correcting the difference between the two (ΘR - Θ'R) to zero value. The stepping motor drive circuit 4b receives both signals R and DP and outputs a rear wheel steering drive signal to the stepping motor 28 to drive it.

With this kind of feedback control, the rear wheel 9
The rear wheel steering device 5 can be driven so that the steering angle becomes the target rear wheel steering angle ΘR.

Next, the mirror control controller 7a operates a calculation circuit 4 that calculates the target mirror angle ΘM1 of the mirror 10.
4, a comparator 45, a correction signal generation circuit 46,
It consists of 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 Θ'R is 0 value, and a mirror reference position storage circuit 50, each of which is configured as follows. It is configured and functions as follows.

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

The arithmetic circuit 44 includes the rear wheel control controller 4
The mode signal MODE and the detected rear wheel turning angle Θ'R are received from the arithmetic circuit 41 and the A/D converter 12a, respectively, and the signal of the mirror reference position M1 is received from the mirror reference position storage circuit 50. Using the data as a parameter, the target mirror angle ΘM1 is calculated using a predetermined function g set in advance in the circuit, and the signal is output to the comparator 45.

On the other hand, the frequency/angle conversion circuit 48 converts the frequency change of the oscillator (mirror angle detector) 7c preset therein into the angle change of the mirror 10 based on the characteristics, and detects the mirror angle. A signal of ΘM′1 is output.

The comparator 45 receives a signal of the target mirror angle ΘM1 from the arithmetic circuit 44 and a signal of the detected mirror angle ΘM'1 from the frequency/angle conversion circuit 48, compares the magnitude of the two, and generates a signal representing the difference. (The absolute value of the difference and the positive/negative sign) are output to the correction signal generation circuit 46.

The correction signal generation circuit 46 receives the signal from the comparison circuit 45 and calculates the difference between the two (ΘM1 - ΘM'1).
The rotation direction switching signal MR and the drive pulse output signal are used as correction signals to correct the value to zero.
MD is output to the mirror motor drive circuit 47, and the mirror motor drive circuit 47 receives both the above signals MR and MD and sends the mirror motor drive signal to the mirror motor 37.
As a result, the mirror motor 37 is driven, and the angle of the mirror 10 is adjusted and controlled so that the detected mirror angle ΘM'1 matches the target mirror angle ΘM1.

The gate 49 is a rear wheel control controller 4a.
The frequency/angle conversion circuit 48 receives a signal of the detected rear wheel turning angle Θ'R from the A/D converter 12a.
When the detected rear wheel steering angle Θ'R receives a signal of the detected mirror angle Θ'1 of 0 value, conduction occurs and the signal of the detected mirror angle ΘM'1 at that time is set to the mirror reference position. It is output to the memory circuit 50.

The mirror reference position storage circuit 50 receives a signal of the detected mirror angle ΘM'1 from the gate 49, and
This is stored in the memory as the mirror reference position M1, and the signal of this mirror reference position M1 is sent to the arithmetic circuit 4.
Output to 4.

In this way, the detected mirror angle ΘM'1 when the detected rear wheel turning angle Θ'R is 0 is set as the mirror reference position M1 via the gate 49, so each driver can adjust the position according to his or her habits and preferences. The mirror reference position M1 can be set for each person by adjusting the angle of the mirror 10 as appropriate.

The signals of vehicle speed rudder, front wheel angle ΘH, and detected rear wheel steering angle Θ'R are input to an AND circuit, and outputted from the AND circuit to gate 49. The gate 49 may be made conductive only when all of 'R' are 0 values.

Further, 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 V, and the control mode signal MOD may be used, or the front wheel steering angle ΘH and target rear wheel turning angle ΘR may be used.

This is because, as illustrated in FIG. 4, the rear wheel steering angle ΘR is calculated using the front wheel steering angle ΘH and the vehicle speed V as parameters, and it is also controlled from the front wheel steering angle ΘH and the rear wheel steering angle ΘR. This is because the mode is determined.

As mentioned above, set changeover switch 6 to "AUTO"
When one of "CRAB" and "CRAB" is selected, the control mode signal MODE is output from the arithmetic circuit 41 of the rear wheel control controller 4a to the arithmetic circuit 44 of the mirror control controller 7a.
MODE, detected rear wheel steering angle Θ′R, and mirror reference position M
The target mirror angle ΘM1 is calculated in the calculation circuit 44 using The angle of the mirror 10 can be adjusted according to the above parameters.
Incidentally, the mirror controller 7a, the mirror drive device 7b, and the mirror angle detector 7c correspond to rear viewing member angle adjusting means.

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

[Brief explanation of drawings]

Among the drawings, FIG. 1 is an overall configuration diagram of the present invention, and FIG.
5 to 5 show embodiments of the present invention, FIG. 2 is an overall configuration diagram, and FIGS. 3a and 3b show the angle of the mirror when traveling backwards in the opposite phase mode and the same phase mode, respectively. An explanatory diagram for explaining the direction to be adjusted and directed, FIG. 4 is a diagram illustrating the characteristics of the rear wheel steering angle with respect to the front wheel steering angle set in the rear wheel control controller, and FIG. 5 is a diagram showing the rear wheel control and FIG. 3 is a block diagram of the entire control system for mirror angle control. DESCRIPTION OF SYMBOLS 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... Stepping motor Driver (stepping motor drive circuit), 5... Rear wheel steering means (rear wheel steering device), 6... Changeover switch, 7... Rear visibility member angle adjustment means, 7a...
Mirror control controller, 7b...Mirror drive device, 7c...Mirror angle detector.

Claims (1)

[Scope of Claims] 1. A front wheel steering means including a steering wheel, a front wheel steering angle detecting means for detecting a steering angle of the steering wheel, and a front wheel steering angle detecting means for detecting a steering angle of the steering wheel; a rear wheel control means for outputting a rear wheel steering drive signal according to an in-phase mode in which the wheels face in the same direction and an anti-phase mode in which the wheels face in the opposite direction; In a four-wheel steering system for a vehicle, comprising a rear wheel steering means for steering the wheels, a signal related to the steering direction of the rear wheels is received from the rear wheel control means, and a rear wheel steering system is configured to visually check the rear wheel in the steering direction of the rear wheels. A four-wheel steering system for a vehicle, characterized in that a rear visibility member angle adjusting means for adjusting the angle of the member is provided.