JPH01214732A - Inspecting apparatus of four-wheel steering characteristic of vehicle and method thereof - Google Patents

Abstract

PURPOSE:To conduct a characteristic inspection accuracy, by a method wherein a simulation signal of a rear wheel steering angle determination factor signal is outputted, the characteristic of a rear wheel steering angle in relation to a front wheel steering angle is detected on the basis of a measured value outputted from a rear wheel angle measuring means, and the characteristic thus detected is compared with a target characteristic. CONSTITUTION:A target steering characteristic varying in accordance with a front wheel steering angle and a vehicle speed is stored in a first memory 100e, while a prescribed target steering characteristic determined by each simulation signal inputted from each simulation signal generating element 105 is found and outputted to a comparing inspection circuit 100g. Meanwhile, a simulation front wheel steering angle signal, a simulation vehicle speed signal and a measured value from a rear wheel angle measuring means 45 are inputted to and stored in a second memory 100f, and it is outputted to the circuit 100g. Next, in the circuit 100g, the target steering characteristic from the memory 100e and a detected steering characteristic from the memory 100f are compared. The result of determination of the circuit 100g is displayed in a display means 200, and the detected steering characteristic is outputted from a printer 202. This output is used on the occasion of adjustment of a rear wheel steering means in the case when the two characteristics are not coincident.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to a four-wheel steering device that can also steer the rear wheels in accordance with the steering of the front wheels, and more specifically, The angle, etc. is input to the controller of the rear wheel steering means via a non-mechanical signal such as an electric signal, and the controller is configured to control the steering of the rear wheels based on the input front wheel steering angle, etc. The present invention relates to an apparatus and method for inspecting the steering characteristics of a vehicle having a four-wheel steering system.

(Conventional technology) Conventionally, four-wheeled vehicles were typically steered by using a steering wheel to steer only the front wheels, but steering only the front wheels could cause the rear wheels to swerve, depending on the driving situation. Problems have been pointed out in terms of maneuverability and steering, such as the limited turning radius and the inability to make small turns.In light of this, a four-wheel steering system that steers the rear wheels as well as the front wheels has recently been proposed and researched. has been done.

In other words, with a four-wheel steering system, when driving at relatively high speeds, if the rear wheels are steered in the same direction as the front wheels (this is called in-phase steering), lateral forces are applied to the front and rear wheels at the same time. Since this is added, there is no phase lag from the steering wheel steering, and the vehicle's attitude can be maintained almost on the tangent to the turning circle, allowing smooth lane changes, for example, when driving at high speeds. Also, if the rear wheels are steered in the opposite direction to the front wheels when driving at very low speeds (this is called reverse phase steering), the direction of the vehicle can be changed significantly, which is convenient for parallel parking or parking in a garage.

Furthermore, considering that the front wheels are not steered significantly at relatively high speeds, and the front wheels are steered significantly when driving at relatively low speeds, the rear wheels are also steered within the range where the front wheels are steered small. It can be seen that a four-wheel steering system is required that steers the rear wheels in the same direction and steers the rear wheels in the opposite direction when turning a large amount.

For this reason, the characteristics of the rear wheel steering angle relative to the front wheel steering angle (hereinafter referred to as The four-wheel steering characteristics, steering characteristics, or simply characteristics) are determined by various factors such as the front wheel steering angle and vehicle speed, and the rear wheels are steered according to the front wheel steering angle based on the steering characteristics. A four-wheel steering system for a vehicle has been proposed in which the steering stability, running stability, etc. are improved.

As one aspect of the four-wheel steering device as described above, the front wheel steering means is provided with a front wheel steering angle sensor, and the above-mentioned steering characteristics are determined by factors other than the front wheel steering angle, or the front wheel steering angle and other factors are determined. If the steering angle is determined by the above factors, sensors are provided to detect those factors, and the front wheel steering angle, etc. is input to the controller of the rear wheel steering means using non-mechanical signals such as electrical signals output from each of the above sensors. It is known that the controller is configured to steer the rear wheels by a predetermined amount based on the input front wheel steering angle and the like.

For example, Japanese Patent Application Laid-open No. 18588/1988 discloses that a vehicle is equipped with a front wheel steering angle sensor, a vehicle speed sensor, and a vehicle loaded weight sensor, and electrical signals indicating the front wheel steering angle, vehicle speed, and vehicle loaded weight are output from these sensors. is input to the controller, and the controller calculates and determines the rear wheel steering angle based on each input signal, and sends a drive signal to the rear wheel steering actuator to steer the rear wheels by the determined rear wheel steering angle. A four-wheel steering device configured to output the following is described.

The above-mentioned four-wheel steering system uses the front wheel steering angle, vehicle speed, and vehicle loading weight as the determining factors for the rear wheel steering angle, and uses these factors to determine the rear wheel steering angle. Various others have been proposed.

For example, only the front wheel steering angle is adopted as the rear wheel steering angle determining factor, the above-mentioned steering characteristic is determined only by the front wheel steering angle, and the rear wheels are steered according to the front wheel steering angle under the steering characteristic. something is proposed.

In addition, the front wheel steering angle and vehicle speed are adopted as factors determining the rear wheel steering angle, and the above-mentioned steering characteristics are determined by the front wheel steering angle and vehicle speed, and under the steering characteristics, the rear wheels are adjusted according to the front wheel steering angle. For example, Japanese Patent Application Laid-Open No. 59-22756
It is described in Publication No. 3.

Furthermore, as in the case where the aforementioned front wheel steering angle, vehicle speed, and vehicle loading weight are adopted as factors determining the rear wheel steering angle, other factors are also adopted in addition to the front wheel steering angle and vehicle speed. Many proposals have been made for further correcting the above-mentioned steering characteristics determined by the angle and vehicle speed based on those factors, and steering the rear wheels according to the front wheel steering angle under the corrected steering characteristics. .

For example, in Japanese Patent Application Laid-open No. 6O-1FT6561, an acceleration sensor is provided to detect the lateral acceleration acting on the vehicle, and when the lateral acceleration detected by the sensor is greater than or equal to the set acceleration, the steering ratio is corrected to decrease. A four-wheel steering device is disclosed.

Furthermore, Japanese Patent Application Laid-open No. 82-8869 discloses a four-wheel steering device combined with a four-wheel drive device equipped with a variable torque distribution mechanism that varies torque distribution between front and rear wheels, and which is equipped with a torque distribution detection sensor. , the steering ratio is corrected according to the change in torque distribution detected by this sensor 4
A wheel steering device is disclosed.

Furthermore, Japanese Patent Application Laid-Open No. 132-8871 is provided with an inclination sensor that detects the downward slope condition of the road surface, and when this sensor detects that the road surface is in the downward slope condition, the steering ratio is changed compared to when it is flat. A four-wheel steering device is disclosed in which correction is made to the same phase side.

Furthermore, in Japanese Patent Application Laid-open No. 62-8872, a friction coefficient sensor is provided to detect the friction coefficient of the road surface, and when the friction coefficient detected by this sensor is low, the rear wheels are steered only in the same phase region. A four-wheel steering device is disclosed.

Furthermore, Japanese Patent Application Laid-Open No. 82-12471 provides a grip force sensor that detects the grip force of a tire, and when the grip force detected by this sensor is low, the steering ratio is corrected in the same phase direction. A four-wheel steering system is disclosed.

Furthermore, Japanese Patent Application Laid-Open No. 62-12472 discloses a vehicle height sensor that detects the vehicle height, and when the vehicle height detected by the sensor is high, the steering ratio is corrected in the same phase direction. A steering device is disclosed.

Furthermore, Japanese Patent Application Laid-Open No. 18387/1987 provides a steering speed sensor that detects the steering speed of a steering wheel, and when the steering speed detected by this sensor is large, the steering ratio is corrected in the same phase direction. A four-wheel steering system is disclosed.

(Problem to be Solved by the Invention) In a conventional vehicle that steers only two wheels, the front wheels are steered proportionally to the operation of the steering wheel, so the horizontal position of the steering wheel and the straight direction of the front wheels are However, in a four-wheel steering system like the one described above, the front wheels are steered proportionally in response to steering wheel operations, but the rear wheels are steered by various factors such as the front wheel steering angle and vehicle speed. Since steering is performed based on the steering characteristics that are determined (changed) by various factors, it is insufficient to inspect the steering characteristics of the rear wheels relative to the front wheels with conventional adjustments alone, and the running stability of the vehicle may be affected if left as is. There is a problem in that it cannot be fully guaranteed.

SUMMARY OF THE INVENTION In view of the above circumstances, an object of the present invention is to provide an inspection device and an inspection method that can easily and accurately inspect the steering characteristics of a four-wheel steering system as described above.

(Means for Solving the Problems) In order to achieve the above object, an inspection device and an inspection method according to the present invention include a front wheel steering means for steering a front wheel, a front wheel steering means for steering a rear wheel, and a front wheel steering means for steering a front wheel; Rear wheel steering comprising a controller to which a rear wheel turning angle determining factor signal consisting of a non-mechanical signal such as an electric signal and including at least a front wheel turning angle signal is input and controlling the steering of the rear wheels based on the signal. An apparatus and method for inspecting four-wheel steering characteristics of a vehicle having a four-wheel steering apparatus comprising means for simulating a rear wheel turning angle determining factor signal including at least the front wheel turning angle signal. A simulated signal output means outputs a signal to the controller, and a steering angle of the rear wheels is set to 4-
Based on the measured values output from the rear wheel angle measuring means and the rear wheel angle determining means, the characteristic of the rear wheel steering angle relative to the front wheel steering angle is detected, and the characteristic is converted into a predetermined target characteristic. and a comparative inspection means for comparing and contrasting the above, and the inspection method includes inputting into the controller a simulated signal of the rear wheel turning angle determining factor signal including at least the front wheel turning angle signal, and Measuring the rear wheel steering angle, detecting the characteristics of the rear wheel steering angle with respect to the front wheel steering angle based on the measured value, and comparing and contrasting the characteristics with a predetermined target characteristic to inspect the four wheel steering characteristics. It is characterized by

Note that the front wheel steering angle determining factor refers to the front wheel steering angle and various factors that determine the above steering characteristics. Therefore, when the steering characteristics are determined only by the front wheel steering angle, the rear wheel turning angle is determined by the front wheel steering angle. The rudder angle determining factor is only the front wheel rudder angle, and if it is determined by factors other than the front wheel rudder angle or by the front wheel rudder angle and other factors, it means the front wheel rudder angle and those factors. do.

Furthermore, the present invention also includes a case where the steering characteristic is fixed and cannot be changed by any factor, and in that case, the only factor determining the rear wheel turning angle is, of course, the front wheel turning angle.

In addition, the factors that determine the above-mentioned steering characteristics include the front wheel steering angle as described above, vehicle speed, lateral acceleration acting on the vehicle, vehicle loading weight, torque distribution between the front and rear wheels, tire grip strength, vehicle height, and steering wheel angle. Examples include steering speed, slope of the road surface, coefficient of friction of the road surface, etc., but the factors are not limited to these, and other types of factors may also be used.

Further, the factors that determine the above-mentioned steering characteristics do not necessarily have to be one type, but may be an appropriate combination of multiple types. Of course, the steering characteristics determined based on these factors are either the steering ratio or the steering phase.
It may be one or both, and the pattern of the steering characteristics (pattern of characteristic lines that connect the steering characteristics for each front wheel turning angle) may be any type. The steering is not limited to any particular type, such as being able to be in phase with respect to the front wheels or only being in opposite phase.

Further, various configurations can be adopted as the rear wheel angle measuring means, for example, it may measure both the left and right wheels, or it may measure only one of the left and right wheels.

Furthermore, the above-mentioned non-mechanical signal means a signal that can transmit information without being accompanied by mechanical displacement, and therefore is not limited to an electrical signal, but may also be an optical signal, a pressure signal, etc., for example.

(Function) By using the above device and method, by sending out a simulated signal of the rear wheel turning angle determining factor signal, the vehicle is not actually brought into a state where a predetermined rear wheel turning angle determining factor signal is output. For example, to accurately and quickly detect the characteristics of the rear wheel turning angle relative to the front wheel turning angle under such predetermined conditions without actually steering the steering wheel or driving the vehicle at a predetermined speed. By adjusting the steering means for the front and rear wheels based on this characteristic test,
It is now possible to accurately adjust the four-wheel steering system,
The running stability of a vehicle having this four-wheel steering device can be fully guaranteed.

(Embodiment) FIG. 1 is a schematic plan view showing an example of a four-wheel steering device to which the present invention is applied.

The illustrated four-wheel steering device uses a front wheel steering angle and a vehicle speed as rear wheel steering angle determining factors, and the front wheel steering means 1
and rear wheel steering means 2.

The front wheel steering means 1 includes a steering wheel 3, a front wheel steering rod 4 having a rack portion 4a that meshes with a binion 3a formed at the lower end of the steering wheel 3, and tie rods 5 connected to both ends of the rod 4. and a knuckle 6 connected to the outer end of the tie rod 5,
The front wheel steering rod 4 is moved in the vehicle width direction in accordance with the 1/ψ rudder of the steering wheel 3, and this movement is caused by the tie rod 5.
is transmitted to the knuckles 6 via the front wheels 7, and the front wheels 7 are steered.

The rear wheel steering means 2 includes a rear wheel steering rod 8 and this rod 8.
, and a knuckle 0 connected to the outer end of the tie rod 9. Similarly to the front wheel steering means 1 described above, the rear wheel steering rod 8 is moved in the vehicle width direction to rotate the rear wheel. Ring 1! is steered.

A rack portion 8a is formed on the rear wheel steering rod 8, and a pinion shaft 12 having a pinion portion 12a that meshes with the rack portion 8a is connected to a stepping motor 15, which is a rear wheel steering actuator, via a pair of bevel gears 13 and 14. The rear wheel steering rod 8 is moved in the vehicle width direction according to the direction and amount of rotation of the motor 15.

The rear wheel steering rod 8 includes a cylinder 16 that is fixed to the vehicle body and supports the rear wheel steering rod 8 so as to be movable in the vehicle width direction. A hydraulic actuator 20 is installed, which consists of a piston 17 that is fixed and slidable within the cylinder IB, and neutral return springs 19a and 19b that are disposed in left and right hydraulic chambers 18a and 18b that are divided by the piston 17. It is being

The left and right hydraulic chambers 18a, 18 of this hydraulic actuator 20
b is a hydraulic line 22a from the control valve 21.
.

22b is connected, and the hydraulic actuator 20 assists the movement of the rear wheel steering rod 8 in the vehicle width direction by the hydraulic pressure supplied from the control valve 21, thereby steering the rear wheels. Note that hydraulic oil in a tank 23 is pressurized and supplied to the control valve 21 by a pump 24 .

Here, the control valve 21 is connected to the pinion shaft 1
2, the hydraulic pressure supplied from the pump 24 is applied to the left and right hydraulic chambers 18a of the hydraulic actuator via either one of the hydraulic lines 22a, 22b depending on the rotational direction of the pinion shaft 12, L8b is supplied to either one of them, and the hydraulic pressure in the other hydraulic chamber is returned to the tank 23 via the other hydraulic line. Then, the stepping motor 15 operates the bevel gears 14.13,
When the rear wheel steering rod 8 is moved in the vehicle width direction via the pinion shaft 12, the movement of the rear wheel steering rod 8 in the vehicle width direction is assisted by the hydraulic pressure of the hydraulic actuator 20.

The hydraulic lines 22a and 22b are connected to a normally closed fail-safe solenoid valve 26 via hydraulic lines 25a and 25b, respectively, and the valve 26 is opened by energizing the solenoid 28a of the valve 26. Sometimes, both side pressure chambers 18a of the hydraulic actuator
, 18b become equal, and the neutral return spring 19a
, 19b positions the piston 17 in the neutral position, and the fail-safe mechanism operates so that the steering angle of the rear wheels 11 is always zero and the steering characteristics of the vehicle are in a two-wheel steering state.

The driving control of the stepping motor 15 is performed by the battery 2.
This is performed by a controller 28 which receives power supply from 7. The controller 28 includes an electric signal (front wheel steering angle signal) consisting of a voltage according to the front wheel steering angle outputted from a front wheel steering angle sensor 29 that detects the front wheel steering angle, and a vehicle speed sensor 30 that detects the vehicle speed. An electric signal (vehicle speed signal) consisting of a voltage corresponding to the vehicle speed outputted from the controller is inputted at any time, and a steering characteristic as a function that changes depending on the front wheel turning angle and the vehicle speed is input and set in advance. Then, the controller 28 determines the front wheel steering angle and vehicle speed from the input front wheel steering angle signal and vehicle speed signal, and determines the steering characteristics corresponding to them from the determined front wheel steering angle and vehicle speed. , calculates the steering angle of the rear wheels from the steering characteristics and the front wheel steering angle, and outputs a drive control signal to the stepping motor 15 to steer the rear wheels 11 by the calculated steering angle, and the motor 15 Based on this signal, it is rotated by a predetermined amount in a predetermined direction.

FIG. 2 shows an example of the steering characteristics that are changed depending on the front wheel steering angle and vehicle speed. The steering characteristics shown in the figure are such that when the vehicle speed is zero, the steering ratio is maximum in the opposite phase, and when the vehicle speed is 30
When touch/H, two-wheel steering occurs at zero phase, and the vehicle speed is 1.
At 20 KIn/H, the steering ratio is maximum with the same phase.

Note that the solenoid 26a of the solenoid valve 26 is energized by the controller 28 in response to a failure signal from a failure detection sensor 31 that detects a failure of the rear wheel steering means 2, for example.
This is done by The controller 28 also controls the drive of the pump 24.

Next, an embodiment of an inspection device for inspecting the four-wheel steering characteristics of a vehicle equipped with the above four-wheel steering device and an embodiment of an inspection method performed using the device will be described.

FIG. 5 is a plan view showing an inspection device 40 for toe-in adjustment and four-wheel steering characteristic inspection. This device 40 includes a front wheel angle measuring means 41 for measuring the toe-in angle, steering angle, etc. , a front wheel guide 43 that guides the left and right front wheels to the front wheel angle determining means 41, a rear wheel angle measuring means 45 that measures the toe-in angle, steering angle, etc. of the rear wheels; Rear wheel guides 47 that guide the rear wheels are arranged in a line as shown in the figure, and the vehicle is transported in the direction of arrow A and the front and rear wheels are guided by the front and rear wheel guides 43 and 47, respectively. and is positioned above the front wheel and rear wheel angle measuring means 41,45. Note that this device 40 includes a simulated signal output means 105 that outputs a simulated fail signal, a simulated front wheel steering angle signal, and a simulated vehicle speed signal to the controller 28 of the vehicle to be inspected, and 4 signals measured by the inspection device 40. It has comparison testing means 100 for comparing wheel steering characteristics with predetermined target characteristics. The comparative inspection means 100 includes front wheel and rear wheel angle measuring means 41.4.
A line 100a-1oad is connected to which the measured values of 6 are input, and a line 100 having a connector 1.5b connected to the vehicle controller is connected to the simulated signal output means 105.
5a is connected.

The front view of FIG. 6 shows the front wheel angle measuring means 41 in detail along the arrow Vl-Vl.
FIG. 7 is a detailed plan view of. As can be seen from the figure, this angle measuring means 41 consists of a pair of testers that are symmetrical in the left and right directions (in the vehicle width direction) in order to measure the toe-in angle and steering angle of the left and right front wheels. Therefore, the same functional parts are given the same numbers and only one of them will be explained.

The angle measuring means 41 includes a full-float turntable 50 that is mounted on a support base 41a and supports the front wheels so that they can be steered and moved left and right and back and forth; A front wheel tester 60 that comes into contact with the outer surface and performs all determinations such as the toe-in angle and steering angle of the front wheels; and a tester moving means 7 that is mounted on the support stand 41a and that moves the front wheel tester 60 in the vehicle width direction.
It consists of 0. The front wheel tester 60 has a measuring plate 61 that comes into contact with the outer surface of the front wheel, and when moved by the tester moving means 70, the measuring plate 61 comes into contact with the outer surface of the front wheel placed on the turntable 50, and this 71
The toe-in angle and steering angle are determined by adjusting the inclination of the 11 constant plate 61 at 111 degrees.

Here, the turntable 50 is shown in detail in FIGS. 8 and 9, and the structure of the turntable 50 will be described. This turntable 50 has a frame 51 made up of a plurality of members fixed to a support base 41a, and a plurality of bearings 52 are fixedly arranged on the upper surface of this frame 51 in line on the same circumference. The bearing 52 has a rotatable ball 52a, and the table 53 is supported by the ball 52a so as to be rotatable and movable back and forth and left and right. This table 53 supports the front wheel by placing it thereon, and is provided with front and rear guides 53a, 53a for positioning the front wheel in the front-rear direction. ) are provided with left and right guide plates 53b for positioning in the direction. Furthermore, a rotating shaft 54 extending downward from the center of the table 53 is attached, and an encoder 55 for detecting the rotation angle of the table 53 is attached to the lower end of this rotating shaft 54. The frame 51 has a table 53.
Transport plate 5 for smoothly transporting the front wheels to
1b and 51b are attached with the table 53 sandwiched in front and behind. Furthermore, shaft holding plates 58.58 are disposed on the frame 51, facing each other so as to sandwich the rotating shaft 54 in the front and back, and being movable back and forth.
The central portions 58a are connected to the upper ends of arms 58 rotatably attached to the frame 51, respectively. The lower end 58c of the arm 5B is connected to both ends of the cylinder 59, and as the cylinder 59 expands and contracts, the arm 58 is rotated and the shaft holding plate 56 is moved back and forth, so that when the cylinder 59 is extended, The two shaft holding plates 5 (i, 5G) approach each other and move away from each other when contracted. FIG. 8A shows a cross section of these two shaft holding plates 56, 58 and the rotating shaft 54 along the arrows As can be seen from this figure, right triangular notches 58a are provided at the mutually opposing ends of the shaft holding plate 50.58, and the rotation shaft 54
The section 54a facing the saw notch 56a has a square cross section that matches the cut.

Therefore, the cylinder 59 is extended and the double shaft holding plate 5
8.58, the notch 5[ia, 58B grips the square portion 54a and holds the rotation shaft 54 fixedly.

Therefore, in the above state, the table 53 also
It is fixed and held in a state where a is facing forward and backward.

Next, the structures of the front wheel tester 60 and the tester moving means 70 will be explained using FIGS. 10 to 12.

The front wheel tester 60 has a support shaft 62 attached to a frame 65 that extends in the vehicle width direction (horizontal direction in the figure), and is rotatable via a ball joint 62a at the center end of the support shaft 62 in the vehicle width direction. A measuring plate 61 is attached. In this state, the measuring plate 61 is rotatable around the ball joint 62a, but the compression spring 63a1 and the tension spring 63b are connected to the frame B5.
It is held in a vertically erect state by the link 63c as shown in the figure.

Note that the measurement plate 61 is held in an upright state when no external force is applied to the measurement plate 61, and this measurement FbL
When 61 receives an external force, the spring 63a.

Measuring plate 6 due to deflection of 63b and deformation of link [i3c]
1 is rotated around the ball joint 62a in response to an external force. Therefore, when the measuring plate 61 is brought into contact with the outer surface of the front wheel, the measuring plate 61 will be tilted according to the inclination of the front wheel, so if the inclination of this measuring plate is measured, the toe-in angle and steering angle of the front wheel can be determined. , camber angle, etc. can be determined. In order to measure the inclination angle of this measuring plate 61, three displacement measuring devices 64 are attached to the frame 65. The displacement measuring device 64 has a probe 84a that protrudes toward the center in the vehicle width direction and is movable in the vehicle width direction.
As shown in FIG. 12, they are attached to the front, rear (left and right in the figure) and above the ball joint 62a. This probe 64a is designed to come into contact with a contact pressure 81a fixed to the measuring plate 61 when the n1 fixed plate 61 comes into contact with the outer surface of the front wheel, and when the measuring plate 61 is tilted. Since a difference occurs in the amount of movement of each probe 64a in the vehicle width direction (movement Q in the vehicle width direction within the displacement measuring device 64), the toe-in angle, steering angle, camber angle, etc. can be detected from this difference. . Specifically, the toe-in angle and steering angle can be measured from the difference in the amount of movement in the vehicle width direction of the probe 64a of the displacement measuring device 64 arranged before and after the ball joint 82a, and the toe-in angle and steering angle can be measured from the difference in the amount of movement in the vehicle width direction of the probe 64a of the displacement measuring device 64 arranged before and after the ball joint 82a. Average value and ball joint 6
The camber angle can be measured from the amount of movement of the displacement measuring device 64 disposed above 2a. Therefore, if only the steering angle is to be measured as in the present invention, only two displacement measuring instruments 64 disposed before and after the ball joint 62a are sufficient. Note that these displacement measuring devices 64 and the like are covered with a cover 60a as shown by the two-dot chain line in FIG.

The front wheel tester 60 configured as described above is supported via the frame 65 by a tester moving means 70 so as to be movable in the vehicle width direction.The structure of this tester moving means 70 and how it supports the front wheel tester θO will be explained. The tester moving means 70 is a frame 7 fixed on the support stand 41a.
1, a pair of front and rear guide rods 72.72 extending in the vehicle width direction by this frame 71, and a transport rod 7 extending in the vehicle width direction between these guide rods 72.72.
4 is supported. Two guide legs 67.137 fixed to the lower surface of the frame 65 of the front wheel tester 60 are slidably fitted onto each guide rod 72, respectively.
Thereby, the front wheel tester 60 is supported movably in the vehicle width direction by the tester moving means 70. Furthermore, a thread is formed on the outer periphery of the transport rod 74, and a threaded bush 66a of the transport force 66 fixed to the lower surface of the frame G5 of the front wheel tester 60 is threadedly engaged with the transport rod 74. The transport rod 74 is rotatably supported by the frame 71, and a first sprocket 75a attached to its end meshes with a second sprocket 75e attached to the shaft of the motor 76 via a chain 75b. By rotationally driving the motor 7G to rotate the conveying rod 74, the front wheel tester 80 is transferred via the conveying force 66.
The entire vehicle can be moved in the width direction of the vehicle. In order to set the moving position in the vehicle width direction at this time, the tester moving means 70
Two limit switches 73, 73 separated in the vehicle width direction are attached to the frame 71 of the front wheel tester 60, and a pair of switch plates 68, 68 facing the limit switches 73 are attached to the frame 65 of the front wheel tester 60. The limit switch 73 is actuated by the contact between the switch plate 68 and the limit switch 73, thereby controlling the drive of the motor 76 to position the front wheel tester 60 in the vehicle width direction.

Although the front wheel angle measuring means 41 has been described above, the rear wheel angle aPj constant hand pitching means will now be described.

Like the front wheel angle measuring means 41, the rear wheel angle measuring means 45 also consists of a pair of left and right testers, and each tester is composed of a full float type turntable 150, a rear wheel tester 180, and a tester moving means 170. There is. As shown in FIG. 13, the turntable 150 includes a frame 151, a plurality of bearings (not shown) attached to the frame 151, and a table 153 supported by the bearings so as to be rotatable and movable back and forth and left and right. These have a slightly different shape from the front wheel turntable 50, but their functions and essential structures are the same, so a description thereof will be omitted. On the other hand, the table 153
A rotating shaft 154 extending downward from the front wheel table 53
The amount of downward extension is smaller than that of the rotating shaft 54, and there is only a square cross section 154a at the lower end, and no encoder is attached to detect the rotation of this shaft. This is because the steering angle of the front wheels in a four-wheel steering vehicle is large, so the front wheel tester 60 alone cannot measure the steering angle. The tester 60 performs a highly accurate n1 constant, and the encoder 55 measures angles exceeding the above range, but the steering angle of the rear wheels is within ±5° of the straight direction. This is because the rear wheel tester 160 alone can sufficiently measure the distance within the range. A pair of shaft holding plates 150 and 156 are arranged so as to sandwich the square cross section 154a at the lower end of the rotating shaft 54 in the front and back, and both shaft holding plates 15G, 1
56 is normally expanded by a spring 157, but each cylinder 158.1 disposed at the front and rear
58 and the square cross-section portion 154a is held between the two shaft holding plates 156 and 156, so that the rotating shaft 15
4 is held fixed. A rear wheel tester 160 that determines the toe-in angle, steering angle, etc. of the rear wheels aPj and a tester moving means 170 that moves this rear wheel tester 160 in the vehicle width direction (left and right direction) are front wheel angle measuring means. Since the functions and essential structures are the same, their explanation will be omitted.

Next, the front wheel guide 43 and rear wheel guide 47 that guide the front and rear wheels to the front wheel angle measuring means 41 and the rear wheel angle measuring means 45, respectively, will be explained. Both guides 4
3.47 has the same shape, so the front wheel guide 43 is shown in FIG. 14 and will be explained based on this. The front wheel guide 43 includes a pair of guide bodies 90.90 each having a guide groove 90a for guiding the left and right front wheels toward the front wheel angle measuring means 41.
These guide bodies 90°90 are movable in the vehicle width direction (horizontal direction). In addition, the guide groove 90a
In order to correctly guide the front wheels, guide plates 91 and 91 that open toward the rear in a "V" shape are installed. Frame 96.97 facing the outer side of both guide bodies 90.90
A first arm 92a and a second arm 92b are attached to which are rotatable and extend rightward in the figure, and both arms 92
a and 92b are connected by a first connecting rod 93. Further, as shown in the figure, the first arm 92a is connected to the guide body 90 that supports the right front wheel by a second connecting rod 95, and the second arm 92b is connected to the frame 97 facing the outer surface of the guide body 90 that supports the left front wheel. The installation is from the front (
The third arm 92c extending to the left in the figure is the second arm 92.
It is rotatably mounted integrally with b, and this third
As shown, the arm 92c is connected by a third connecting rod 94 to a guide body 90 that supports the left front wheel. Therefore, by moving the first connecting rod 93 in the vehicle width direction using a cylinder (not shown) or the like, both guide bodies 90 and 90 can be moved in opposite directions in the vehicle width direction, thereby allowing the front wheel Even if the treads of the two guide bodies 90 and 90 are different, the distance between the guide bodies 90 and 90 can be adjusted according to the treads.

Further, lids 48 and 49 for lifting and supporting the vehicle body are provided before and after the front wheel guide 43 (see FIG. 5). As shown in FIG. 15, which shows a cross section taken along the arrow xv-xv in FIG. The rod 101 can freely protrude upward, and the head 1 has a groove 101b at its upper end.
ola is attached.

Therefore, when the rod 101 of the cylinder 102 is extended upward, the groove 101b of the head 101a receives the side sill of the vehicle body and lifts the vehicle body. When the front and rear wheels are placed on full-float turntables, if an external force is applied to the vehicle body in the horizontal direction, the turntables will be moved and the vehicle body will be moved, causing inaccurate measurements by the front and rear wheel angle measuring means. However, by lifting and supporting the vehicle body with the lifter, it is possible to prevent the vehicle body from being moved even when a horizontal external force is applied to the vehicle body. Furthermore, by lifting the vehicle body using the lifter, the weight of the vehicle that is applied to the tires placed on the turntable can be reduced, thereby reducing the deformation of the tires and reducing the load on the turntable. It is made small so that the turntable can rotate smoothly.

Next, a first embodiment of the simulated signal output means 105 and comparison inspection means 100 will be described in detail with reference to FIG. 3.

The simulated signal output means 105 is the simulated front wheel turning angle signal generator 1
05c, a simulated vehicle speed signal generating section 105d and a simulated fail signal generating section 105e, each simulated signal generating section 105
The simulated signals outputted from c to 105e are inputted to the signal input section 28a of the controller of the rear wheel steering means and the first memory 100c of the comparison inspection means described below, and the simulated front wheel steering angle signals and the simulated The heavy speed signal is further explained below in the second memo of comparative inspection means January 0
You can also input it to 0r.

Further, when the simulated front wheel turning angle signal generating section 105c finishes outputting the predetermined simulated front wheel turning angle signal, a completion signal is outputted from the first. The completion signal is configured to be output to the second memories 100c and 10(H).The completion signal may be input by the operator to both memories 100c and 1001', or may be generated by generating other simulated signals. Parts 105d, 105e
The data may be input to both memories 100e and 1001' from there.

The comparison test means 100 comprises a first memory t00es, a second memory 100r, and a comparison test circuit 100g.

The first memory 100e stores the target steering characteristics shown in FIG. 2 that change according to the front wheel turning angle and the vehicle speed, and the target steering characteristics when the fail signal is input, and input from each of the simulated signal generators 105c to 105e. A predetermined target steering characteristic is determined based on each of the simulated signals, and the target steering characteristic is determined by the comparative inspection circuit 10 upon receiving the completion signal.
Output to 0g.

The second memory 100' stores the simulated front wheel steering angle signal, the simulated vehicle speed signal, and ΔIll from the rear wheel angle measuring means 45.
A fixed value is inputted, these continuously inputted signals and measured values are stored, and upon receiving the completion signal, they are outputted to the comparative inspection circuit 100g, and then reset. The second memory 100r is configured so that not only the measured values of the rear wheel angle measuring means 45 but also the measured values of the front wheel angle measuring means 41 are inputted. This is for toe-in adjustment, and input from the measuring means 41 is not necessary if only the four-wheel steering characteristics are to be inspected.

The comparison test circuit 100g determines whether the target steering characteristic inputted from the first memory 100e matches the detected steering characteristic detected based on the data inputted from the second memory.

The determination result made in the comparison test circuit 100g is displayed on the display means 200 in the form of whether or not the two characteristics match, and the detected steering characteristic is displayed on the printer 200.
2, and this output is used when adjusting the rear wheel steering means 2 when the two characteristics do not match.

Note that, instead of adopting a method of temporarily storing the rear wheel angle measurement values and the like as in the second memory 100r, the data may be continuously input to the direct comparison detection circuit 100g. In this case, the first memory 100e
The target steering characteristics are also continuously inputted from
It is preferable to input a predetermined simulated signal from the tester to obtain the 1'' target steering characteristic in the test to be performed in advance.

Further, for example, a predetermined angular velocity is stored in the first memory 100e, and the simulated front wheel turning angle signal generation unit 105C outputs a simulated front wheel turning angle signal corresponding to the case where the front wheels are steered by a predetermined angle or one reciprocation at the predetermined angular velocity. may be generated. In this case, in order to determine the origin input from the rear wheel angle measuring means 45, that is, to specify the rear wheel turning start position, for example, the measurement start position is always set to the rear wheel turning angle field. , simulated front wheel turning angle signal generation unit 105
It is preferable to output the simulated front wheel turning angle signal from zero at c.

Note that if the simulated front wheel turning angle signal input to the controller 28 is known as in the above case, the comparison inspection circuit 100g does not need to input this signal from the second memory 1001' to the comparison inspection circuit 100g. 100g can detect the steering characteristics, so the simulated front wheel steering angle signal is stored in the second memory 1.
There is no need to input it to 00f. Similarly, if the simulated signals outputted from the simulated signal generators 105c and 105d are known to the comparison test circuit 100g by some method, the simulated signals outputted from both sales units 105c and 105d are used as the second There is no need to input it to the memory 100r.

A method of inspecting the four-wheel steering characteristics of a vehicle equipped with the four-wheel steering system shown in FIG. 1 using the inspection apparatus 40 as described above will be described. First, each cylinder 59.158 of the front wheel turntable 50 and the rear wheel turntable 150
, 158 are extended and the shaft holding plates 58, 58 and 15
6, 156, the vehicle is conveyed onto this device 40 from the right side in FIG. 5 in the direction of arrow A, and the front wheel and rear wheel guides 43
．． 47, the front wheel 7 and the rear wheel 11 are placed on the front and rear wheel angle measuring means 41, 45, respectively.

Next, the heads 101a of the lifters 4B and 49 are moved upward, and the heads 101a lift the side sills of the vehicle body to reduce the loads from the front and rear wheels to the turntable 50, 150, and also to hold the vehicle body and prevent it from being damaged by external forces. Prevent horizontal movement. The lifting force of the vehicle body by the lifters 48 and 49 is set so that a load remains on the table 53.153 to the extent that the table 53.153 can be rotated smoothly in accordance with the steering of the front and rear wheels.

Next, each cylinder 59.158.158 of the front wheel turntable 50 and the rear wheel turntable 150 is contracted to release the fixed holding of the rotating shaft 54.154 by the shaft holding plates 56.56 and 158.158, and the table 53.1
53 to full float state.

From this state, toe-in adjustment of the front wheels and rear wheels is first performed. In this toe-in adjustment, the toe-in angle is measured by the tester 60.160 of the front wheel and rear wheel angle ΔIIJ determining means 41.45, and the toe-in angle is measured with the front and rear wheels facing straight and the steering wheel facing horizontally. Ap is performed so that the angle becomes a predetermined value, but a detailed explanation of the adjustment method will be omitted. In addition,
The toe-in adjustment here includes not only the so-called wheel toe-in: J3 adjustment but also the adjustment in the toe-out direction.

After the toe-in adjustment described above, the four-wheel steering characteristics are inspected. This four-wheel steering characteristic inspection is performed by measuring the relationship between the steering angle of the front wheels 7 and the steering angle of the rear wheels 11.
The specific inspection method will be explained below.

First, a method for inspecting the operation of a fail-safe mechanism, which is a first embodiment of the method of the present invention, will be described. For this inspection, first, connect the connector 105b of the simulated signal output means 105 to each sensor 29, 3 of the vehicle to be inspected.
0.31 is connected to the signal input section 28a of the controller, and then a simulated maximum front wheel rotation signal is input from the simulated front wheel steering angle signal generation section 105c in order to steer the rear wheels as much as possible in either the left or right direction. In addition to outputting a steering angle signal, a simulated vehicle speed signal (
For example, vehicle speed 0 KJn/H or 120 KJn/H
The simulated vehicle speed signal generating section 105d outputs a vehicle speed signal corresponding to , and sends these simulated signals to the controller 28 and the comparative inspection means 100. At this time, the steering angle of the rear wheels is measured by the rear wheel angle measuring means.

Next, a simulated fail signal is outputted from the simulated fail signal generator 105c, and the controller 28 energizes the solenoid 37e of the failsafe solenoid valve 37 to open the solenoid valve 37. In other words, the failsafe mechanism is activated. When the solenoid valve 37 is opened, as described above, the oil pressures in the pressure chambers 18a and 18b on both sides of the hydraulic actuator become equal, and the biasing force of the neutral return springs 19a and 19b causes the piston 1 to
7 should be positioned at the neutral position and the rear wheels should be in a straight-ahead state (state where the steering angle is zero). The comparison test circuit 100g detects the characteristic of the rear wheel steering angle relative to the front wheel steering angle, that is, the steering characteristic, and determines whether this detected steering characteristic corresponds to the preset target steering characteristic, that is, the total front wheel steering angle. On the other hand, it is checked whether the rear wheel steering angle conforms to the characteristic that it is zero, that is, whether the fail-safe mechanism is operating.

Next, a second embodiment of the inspection method according to the present invention will be described. For this test, first connect the connector 105b of the simulated signal output means 105 to the signal input section 2B of the controller as in the case described above.

Subsequently, the simulated front wheel turning angle signal generating section 105c outputs a simulated front wheel turning angle signal corresponding to the case where the front wheels 7 are turned reciprocally within a predetermined range around the straight-ahead direction. In this case, the front wheel turning angle range may be a small range, for example, in this example, about ±3°.

Since the rear wheels 11 are steered by this simulated front wheel steering angle signal, the characteristic test is performed by determining the rear wheel steering angle at this time. For convenience, it is preferable to input a simulated vehicle speed signal that maximizes the steering ratio to the controller 28. For this reason,
A simulated vehicle speed signal (vehicle speed 0 touch/H or 120 KIn/H) that maximizes the steering ratio is generated from the simulated vehicle speed signal generation unit 105d.
(vehicle speed signal corresponding to) is sent to the controller 28.

The rear wheel angle measuring means 4 measures the steering angle of the rear wheels under the above conditions.
5, the measured value and the simulated front wheel turning angle signal are input to the comparison test circuit 100g via the second memory toor, and the steering characteristic is detected from the input data in the comparison test circuit 100g. .

An example of this detected steering characteristic is shown with the rear wheel steering angle on the vertical axis.
When the front wheel turning angle is plotted on the horizontal axis, a trajectory with a constant hysteresis H is obtained, as shown by the solid line in the graph of FIG. In this case, the rear wheel steering angle when the front wheel steering angle is zero is: J! If the J adjustment is adjusted based on the steering of the front wheels in either the right or left direction, the steering angle of the rear wheels will shift when the wheels are steered in the other direction, impairing running stability. Therefore, in the present invention, in the comparison test circuit 100g, whether or not the curve β representing the midpoint of both trajectories passes through the origin on the graph (that is, the trajectory curve obtained by rightward steering and the leftward steering In other words, whether or not the trajectory curve obtained by I'm trying to check if that's the case. Then, the rear wheel steering means is adjusted so that the curve β passes through the origin.

In the vehicle using the four-wheel steering system shown in FIG. 1, the neutral return springs 19a and 19b are precompressed, so the rear wheels 11 are rotated from the straight-ahead position (the position where the steering angle is zero) to the left and right positions. When steering in any direction, the dead zone where the rear wheels are not steered when the front wheels are steered (the part in the graph where the trajectory curve is almost horizontal near where the front wheel steering angle is zero) ) occurs. Therefore, for example, when this dead zone occurs, the front wheel steering angle α1. Read α2, both steering angles α1. It is checked whether the median value of α2 is zero (that is, whether both dead zones are point symmetrical about the origin), that is, the median value of α1 and α2 where αl and α2 are It may be checked whether the "one target steering characteristic" of zero is met.
Further, a third embodiment of the inspection method according to the present invention will be described below. First, as in the case described above, the connector 105b of the simulated signal output means 105 is connected to the signal input section 28a of the controller. Subsequently, a simulated vehicle speed signal (for example, a vehicle speed of 120 KIn) is generated from the simulated vehicle speed signal generating section 105d that sets the steering phases to the same phase and maximizes the n steering ratio.
/H). In this state, when the simulated front wheel steering angle signal generator 05c outputs a simulated front wheel steering angle signal corresponding to the case where the front wheels 7 are made to reciprocate left and right once, the rear wheels 11 are also steered in the same phase. This rear wheel steering angle is determined 1iTllj by the rear wheel angle measuring means 45, and the measured value and the simulated front wheel steering angle signal are stored in the second memory 100.
f to the comparison test circuit 100g, and the circuit 10
Steering characteristics are detected from those data input at 0g. The graph in FIG. 17 shows an example of this detected steering characteristic. In this graph, the vertical axis shows the rear wheel steering angle, the horizontal axis shows the front wheel steering angle, and the upper side of the vertical axis and the right side of the horizontal axis shows the steering of the rear wheels and front wheels to the right. ing. As can be seen from this graph, when a simulated front wheel turning angle signal that turns the front wheels to the right is sent, the rear wheels are also turned to the right (steered in the same phase) in response. This change in the turning angle of the rear wheels gradually becomes smaller and the rear wheels are not steered at a predetermined turning angle (maximum turning angle on the right side) 01 or more.

The same is true when a simulated front wheel steering angle signal is sent to steer the front wheels to the left, and the rear wheels are in the same phase and the left maximum steering angle θ2
The steering wheel is steered while gradually reducing the change until the end.

Next, the simulated vehicle speed signal generator 105d generates a simulated vehicle speed signal (for example, vehicle speed 30KIn) that makes the steering phase zero phase.
/H). In this state, similarly to the above, a simulated front wheel turning angle signal corresponding to the case where the front wheels 7 are made to reciprocate left and right once is sent out.

However, in this case, the rear wheels 11 should be maintained at zero phase and not steered. This rear wheel steering angle is rear wheel angle A
The steering characteristic is measured by the 111 constant means 45, and based on the measured value, the steering characteristic is detected in the comparison test circuit 100g in the same manner as in the above case. The graph in FIG. 18 shows an example of this detected steering characteristic. As can be seen from this graph, even if a simulated front wheel steering angle signal that turns the front wheels left and right is sent, the rear wheels are hardly turned, and the turning angle θ1 is extremely small due to dimensional errors. Only θ2 occurs.

Further, a simulated vehicle speed signal (from the simulated vehicle speed signal generation unit 105d) that reverses the steering phase and maximizes the steering ratio (
For example, a vehicle speed signal corresponding to a vehicle speed of 0-/H is sent out. In this state, if a simulated front wheel steering angle signal corresponding to the case where the front wheels 7 are reciprocated left and right once is sent out in the same way as above, the rear wheels 11 are steered in the opposite phase, so this rear wheel steering angle is is measured by the rear wheel angle measuring means 45, and based on the measured value, the steering characteristic is detected in the comparison test circuit 100g in the same manner as in the above case. The graph in FIG. 19 shows an example of this detected steering characteristic. As can be seen from this graph, when a simulated front wheel steering angle signal that turns the front wheels to the right is sent, the rear wheels are accordingly turned to the left (steered to the opposite phase). This change in the steering angle of the rear wheels gradually becomes smaller and the rear wheels are not steered at a predetermined steering angle (maximum left steering angle) of 01 or more. The same is true when a simulated front wheel turning angle signal for steering the front wheels to the left is sent out, and the rear wheels are steered in the opposite phase while gradually reducing the change up to the maximum right turning angle θ2.

One predetermined drifting steering characteristic is set in advance for each of the detected steering characteristics detected as described above when various simulated signals are sent out, and both of the above characteristics are compared using the comparison inspection port 100g. It is checked whether the detected characteristics are within the required range of the target characteristic and whether the maximum steering angles θ1 and θ2 are within a predetermined range as the target characteristic set in advance. If not, that is, if the above-mentioned target characteristics are not met, the steering characteristics are adjusted so as to match the target characteristics.

Furthermore, a fourth test is conducted to test the four-wheel steering characteristics according to the present invention.
An example will be explained. In this method, the front wheel 7
A simulated front wheel steering angle signal that causes the vehicle to be largely steered (preferably to a maximum steering angle) is sent, and a simulated front wheel speed signal that changes the vehicle speed under that condition, for example, a vehicle speed of 0Ktn.
A signal corresponding to a vehicle speed that gradually increases from /H to a vehicle speed of 120/H is sent out. Then, the rear wheel steering angle at this time is measured by the rear wheel angle measuring means 45, and the tl11 constant value and the simulated vehicle speed signal are inputted to the comparison inspection circuit 100g via the second memory Ioor. The steering characteristics are detected from those data. The graph in FIG. 20 shows an example of the detected steering characteristic, that is, the relationship between the rear wheel turning angle and the vehicle speed (simulated vehicle speed signal).

In this graph, the vertical axis shows the rear wheel steering angle, and the horizontal axis shows the vehicle speed. As can be seen from this graph, when the vehicle speed is zero, the rear wheels are steered in the opposite phase to the front wheels. The maximum steering angle is 50, and as the vehicle speed increases from this state, the rear wheel steering angle gradually decreases.
At a vehicle speed of 30 KJn/H, the rear wheel steering angle is zero, that is, the vehicle is in a two-wheel steering state. When the vehicle speed further increases, the rear wheels are now steered to the same phase side, and the amount of steering to the same phase side increases as the vehicle speed increases, but the rate of increase gradually decreases. , reaches its maximum at a vehicle speed of 120 tach/h, and its value is 5''.In this way, the detection steering characteristic that indicates the change in the rear wheel steering angle with respect to the change in vehicle speed under the predetermined front wheel steering angle determined by n1. For this, a predetermined target steering characteristic is set in advance, and a comparative inspection circuit 1000g compares both of the above-mentioned characteristics to check whether the detected characteristic is within the required range of the target characteristic, and if it is not, In other words, when the steering characteristics do not match the target characteristics, the steering characteristics are adjusted so as to match the target characteristics.

FIG. 4 shows the simulated signal output means 105 and the comparative inspection means 100.
It is a figure which shows the 2nd Example of.

In this embodiment, the simulated signal output means 105 includes memory units 1051', 105g, and 105h for the simulated front wheel turning angle signal generator 105c, the simulated vehicle speed signal generator 105d, and the simulated fail signal generator 105e, respectively. Each memory section stores each of the simulated signals necessary for the test to be performed, and also stores the order of the tests if a plurality of tests are to be performed. Therefore, when the test is started, the simulated signal output means 105 outputs a group of simulated signals necessary for each test in the order of tests stored in advance, and is configured to be inputted to the signal input section 28a of the vehicle controller. .

Further, the test start signal and completion signal of each test are also stored in the memory section 105r of the simulated front wheel turning angle signal generating section 105c, and the start signal and completion signal for each test are the simulated front wheel turning angle signal. The signal is inputted from the generating section 105c to the signal input section 28e of the controller as well as to the first memory 100e and second memory 100r of the comparative inspection means described below. Note that the start and completion signals may be output by the operator, or may be output by another simulated signal generator 1.
It is also possible to output from 05d and 105e.

The first memory 100e of the comparison test means stores the target steering behavior in the test stored in each memory part of the simulated signal output means 105 in the order in which they are stored in each memory part. The measured value from the rear wheel angle measuring means 45 is input into the second memory 100r as in the above embodiment, and the memory stores the measured value. Note that the second memory 100r is also configured to receive measured values for toe-in adjustment from the front wheel angle measuring means 41, as in the case of the above embodiment. The outputs of the two memories 1ooe and 100f are input to a comparison test circuit 100g.

The outputs of both memories 100e and 100f' are controlled by the test start signal and completion signal. in particular,
When the first start signal is output, preparations are made in the first memory 100a to output the stored target steering characteristics of the first test, and following this start signal, as described in the first embodiment, A simulated front wheel steering angle signal in the steering angle field for determining the origin of the rear wheels is input to the controller 28, and then a group of simulated signals is input to the controller 28 from the simulated signal generating means 105 in accordance with the pattern of the first inspection. and the steering angle of the rear wheels 11 steered by the controller 28 accordingly is transmitted from the rear wheel steering angle measuring means 45 to the second
The second memory stores the measured value. Then, when the test completion signal is output, the first memory 1one receives the completion signal and compares and compares the target steering characteristic of the first test prepared above with the test circuit 10.
0g, and the second memory 100r also receives the completion signal and outputs the stored rear wheel steering angle measurement value to the comparative inspection circuit 100g, where the comparison inspection circuit 100g receives the completion signal from the second memory 100. Detecting the steering characteristic based on the measured value, determining whether or not the detected steering characteristic matches the target steering characteristic inputted from the first memory 100e, and displaying the determination result on the display means 200. , the detected steering characteristics are sent to the printer 2 as necessary.
02, and after the completion signal is output, a start signal for the second test is output at a predetermined interval, and thereafter, the second and third tests are performed in the same manner as the first test.
．． ...... will be inspected.

Of course, it is also possible to perform the first to fourth embodiments of the above-described inspection method using the simulated signal output means and comparative inspection means of the second embodiment.

In the above-mentioned embodiment, the four-wheel steering system that adopted the front wheel steering angle and the vehicle speed as the determining factors for the rear wheel steering angle was tested, but the four-wheel steering system that is the subject of the present invention is Other factors other than these may be adopted as rear wheel turning angle determining factors, and in that case, of course, a simulation signal of the other factors mentioned above is output from the simulation signal output means at the time of inspection,
What is necessary is to input it into the controller of the inspection vehicle.

(Effects of the Invention) As explained above, the inspection apparatus and method according to the present invention output a simulated signal of the rear wheel turning angle determining factor signal including at least the front wheel turning angle signal from the simulated signal output means to the controller of the test vehicle. The steering angle of the rear wheels steered by the controller based on the input signal is measured by the rear wheel angle measuring means, and the four-wheel steering of the test vehicle is performed based on this measured value in the comparative testing means. The steering wheel is configured to detect the steering characteristic and compare and inspect the detected steering characteristic with a predetermined target steering characteristic.

Therefore, by using these devices and methods, by sending out a simulated signal of the rear wheel turning angle determining factor signal, it is possible to send out a simulated signal of the rear wheel turning angle determining factor signal without actually putting the vehicle in a state where a predetermined rear wheel turning angle determining factor signal is output. In particular, it is possible to accurately and quickly measure and detect the four-wheel steering characteristics without actually steering the steering wheel or, for example, without actually driving the vehicle at a predetermined speed. From the comparison, it is possible to accurately determine whether the steering characteristics of the four-wheel steering system are good.

Furthermore, according to the apparatus and method of the present invention, there is no need to actually steer the front wheels, so the front wheel steering means and the rear wheel steering means can be kept separate, that is, the rear wheel steering means can be used alone. It is also possible to submit it for inspection.

[Brief explanation of the drawing]

Fig. 1 is a schematic plan view of a four-wheel steering system of a vehicle, Fig. 2 is a graph showing an example of steering characteristics, Fig. 3 is a diagram showing an example of a simulated signal output means and a comparative inspection means, and Fig. 4 is a diagram showing an example of a simulation signal output means and a comparative inspection means. 5 is a plan view showing the inspection device; FIGS. 6 and 7 are a front view and a plan view of the front wheel angle measuring means; FIGS. Figure 9 is a front sectional view and side view showing the turntable for the front wheel, Figure 8A is a sectional view showing the turntable along the arrows ■-■, Figures 10 to 12 are the front wheel tester and tester moving means. Fig. 13 is a front view showing the turntable for the rear wheels, Fig. 14 is a plan view showing the front wheel guide, Fig. 15 is a sectional view showing the beam cover, Fig. 16 20 are graphs showing an example of detected steering characteristics. 1... Front wheel steering means 2... Rear wheel steering means 7.
...Front wheel 11...Rear wheel 28...Controller 40...Inspection device 45...Rear wheel angle measuring means 100...Comparative inspection means 105...Simulation signal output means Fig. 3 Fig. 4 Fig. 9 ψ Ov 5 ψ Fig. 12 Fig. 14 Bar 1 92C Sodo O Fig. 16 Fig. 17 Width eaves 7 Ha Fig. 19

Claims (2)

[Claims] (1) A front wheel steering means for steering the front wheels, and a factor for determining the rear wheel turning angle, which is composed of non-mechanical signals such as electrical signals and includes at least a front wheel turning angle signal. A device for inspecting four-wheel steering characteristics of a vehicle having a four-wheel steering device comprising: a rear wheel steering means having a controller that receives a signal and controls the steering of the rear wheels based on the signal; a simulated signal output means for outputting a simulated signal of a rear wheel turning angle determining factor signal including at least the front wheel turning angle signal to the controller; and a rear wheel angle measuring means for measuring a rear wheel turning angle. , comprising a comparison inspection means for detecting a characteristic of a rear wheel turning angle with respect to a front wheel turning angle based on a measured value output from the rear wheel angle measuring means, and comparing and contrasting the characteristic with a predetermined target characteristic. A vehicle four-wheel steering characteristic inspection device characterized by comprising: (2) A front wheel steering means for steering the front wheels, and a rear wheel turning angle determining factor that is composed of non-mechanical signals such as electrical signals and includes at least a front wheel turning angle signal. A method for inspecting the four-wheel steering characteristics of a vehicle having a four-wheel steering device comprising: a rear wheel steering means having a controller that receives a signal and controls the steering of the rear wheels based on the signal; Then, a simulated signal of the rear wheel turning angle determining factor signal including at least the front wheel turning angle signal is input to the controller, the rear wheel turning angle at that time is measured, and the front wheel turning angle is determined based on the measured value. A four-wheel steering characteristic testing method for a vehicle, comprising detecting a characteristic of a rear wheel turning angle, and comparing and contrasting the characteristic with a predetermined target characteristic to test the four-wheel steering characteristic.