JP2660345B2 - Apparatus and method for inspecting four-wheel steering characteristic of vehicle - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a four-wheel steering device capable of steering a rear wheel together with a front wheel, and in particular, a steering angle of a rear wheel is set at a vehicle speed. The present invention relates to an apparatus and a method for inspecting a steering characteristic of a vehicle having a four-wheel steering device that is variably controlled (changed) according to a predetermined traveling state of the vehicle.

(Prior Art) Conventionally, in steering of a four-wheel vehicle, only the front wheels are normally steered by a steering wheel. However, when only the front wheels are steered, a side slip may occur on the rear wheels or a turning radius may occur depending on a driving condition. Problems were pointed out in terms of maneuverability and maneuverability, such as limited turnability and small turning was not effective. In view of this, recently a four-wheel steering system that steers both the front and rear wheels was proposed.
Has been studied.

That is, in a four-wheel steering system, when the rear wheels are steered in the same direction as the steering direction of the front wheels during traveling at a relatively high speed (this is referred to as in-phase steering), lateral forces are simultaneously applied to the front and rear wheels. As a result, the phase of the steering wheel is not delayed, and the posture of the vehicle can be maintained almost on the tangent to the turning circle. For example, lane changes during high-speed running can be smoothly performed. If the rear wheels are steered in a direction opposite to the steering direction of the front wheels during traveling at an extremely low speed (this is referred to as anti-phase steering), the direction of the vehicle can be greatly changed, which is convenient for parallel parking or garage parking.

For this reason, a mechanism for arbitrarily variably controlling the steering ratio of the rear wheel to the front wheel (the absolute value of the ratio of the steering angle of the rear wheel to the steering angle of the front wheel) and the steering phase is provided. It has been proposed that the steering ratio or the steering phase is variably controlled to improve the maneuverability and the running stability. For example, as disclosed in Japanese Patent Application Laid-Open No. Sho 61-108070, there is a four-wheel steering device in which a turning phase and a turning ratio are variably controlled according to a vehicle speed.

There is also a four-wheel steering device that variably controls a turning ratio and a turning phase in consideration of not only a vehicle speed but also a predetermined traveling state of another vehicle.

For example, Japanese Patent Application Laid-Open No. 60-166561 discloses an acceleration sensor that detects a lateral acceleration acting on a vehicle. When the lateral acceleration detected by this sensor is equal to or higher than a set acceleration, the steering ratio is reduced and corrected. A disclosed four-wheel steering device is disclosed.

Japanese Unexamined Patent Publication (Kokai) No. 61-18568 discloses a four-wheeled vehicle in which a vehicle loading weight sensor is provided, and the steering ratio is corrected in the same phase direction as the loading weight detected by the sensor increases. A steering device is disclosed.

Japanese Patent Application Laid-Open No. Sho 62-8889 discloses a four-wheel steering device combined with a four-wheel drive device having a variable torque distribution mechanism for varying the torque distribution to the front and rear wheels, wherein a torque distribution detection sensor is provided. There is disclosed a four-wheel steering apparatus that corrects a steering ratio in accordance with a change in torque distribution detected by the sensor.

Japanese Patent Application Laid-Open No. 62-8871 discloses an inclination sensor for detecting a downhill condition of a road surface. When the sensor detects that the road surface is downhill, the steering ratio is set to be lower than when the road surface is flat. There is disclosed a four-wheel steering device that corrects in-phase.

Japanese Patent Application Laid-Open No. 62-8872 discloses a friction coefficient sensor that detects a friction coefficient of a road surface. When the friction coefficient detected by this sensor is low, the rear wheels are steered only in the same phase region. A disclosed four-wheel steering device is disclosed.

Japanese Patent Application Laid-Open No. 62-12471 discloses a grip force sensor for detecting a grip force of a tire. When the grip force detected by the sensor is low, the steering ratio is corrected in the same phase. A four-wheel steering device is disclosed.

Japanese Patent Application Laid-Open No. Sho 62-12472 discloses a four-wheel vehicle in which a vehicle height sensor for detecting a vehicle height is provided, and when the vehicle height detected by this sensor is high, the steering ratio is corrected in the same phase direction. A steering device is disclosed.

In Japanese Patent Application Laid-Open No. 62-18367, a steering speed sensor for detecting the steering speed of a steering wheel is provided, and when the steering speed detected by this sensor is high, the steering ratio is corrected in the same phase direction. A four-wheel steering device is disclosed.

(Problems to be Solved by the Invention) In a conventional vehicle that only steers two wheels, the front wheels are relatively steered by the operation of the steering wheel. However, in the four-wheel steering system, the front wheels are relatively steered in response to the operation of the steering wheel, but the rear wheels are driven by various vehicle running conditions such as the vehicle speed as described above. Since the steering wheel is steered so as to have a different steering angle depending on the vehicle, the inspection of the steering characteristics of the rear wheels with respect to the running state of various vehicles is insufficient with only the conventional adjustment, and the running stability of the vehicle is left as it is. There is a problem that the property cannot be sufficiently guaranteed.

(Means for Solving the Problems) The present invention has been made in view of the problems of the conventional method as described above,
An object of the present invention is to provide a method capable of accurately and promptly inspecting the characteristics of a wheel steering device so as to solve the above-mentioned problem. A front wheel turning means for turning the front wheels, and a predetermined running state signal from a running state sensor for detecting a predetermined running state of the vehicle. A device for inspecting a four-wheel steering characteristic of a vehicle having a four-wheel steering device including a rear-wheel steering device for performing rear-wheel steering based on a characteristic of an angle, and measuring a rear-wheel steering angle. Rear wheel turning angle measuring means, simulation signal sending means for outputting a simulation signal of the predetermined traveling state signal to the rear wheel steering means, and a predetermined running state based on the simulation signal when the simulation signal is transmitted. Features of rear wheel steering angle Detects, characterized in that comprising a comparison inspection means the the characteristic is compared against a characteristic of the steering angle of the rear wheels with respect to the predetermined running state is the preset.

According to another embodiment of the present invention, there is provided an inspection apparatus for controlling a front wheel to perform steering of a front wheel and a traveling state signal from a traveling state detection sensor for detecting a predetermined traveling state of the vehicle. The steering ratio or the turning phase characteristic of the rear wheel with respect to the front wheel is variably controlled in response to the predetermined running state signal, and the turning of the rear wheel is performed based on the steering ratio or the turning phase characteristic of the rear wheel with respect to the front wheel. The rear wheel turning means for performing
Apparatus for inspecting four-wheel steering characteristics of a vehicle having a wheel steering device, comprising: front wheel steering angle measuring means for measuring a steering angle of a front wheel; and rear wheel steering angle measuring means for measuring a steering angle of a rear wheel. Simulation signal transmitting means for outputting a simulation signal of the predetermined traveling state signal to the rear wheel steering means, and a steering ratio or a steering phase characteristic of the rear wheel with respect to the front wheel when the simulation signal is transmitted. Detecting means for detecting and matching the characteristic with a predetermined running state based on the simulation signal and comparing with a preset steering ratio of the rear wheel to the front wheel or a steering phase characteristic. .

Further, in order to achieve the above object, the inspection method of the present invention receives a predetermined traveling state signal from a front wheel steering means for performing steering of a front wheel and a traveling state detection sensor for detecting a predetermined traveling state of the vehicle. A four-wheel steering characteristic of a vehicle having a four-wheel steering device including a rear-wheel steering device for performing rear-wheel steering based on characteristics of a rear-wheel steering angle with respect to the predetermined traveling state set in advance. A method of inspecting, comprising: sending a simulation signal of the predetermined traveling state signal to the rear wheel steering means; measuring a steering angle of the rear wheel at this time; and determining a predetermined steering signal based on the simulation signal obtained by the measurement. The characteristic of the steering angle of the rear wheel with respect to the traveling state of the vehicle is compared with the characteristic of the steering angle of the rear wheel with respect to the predetermined traveling state, and the four-wheel steering characteristic is inspected. It is characterized by.

The running state of the vehicle includes, for example, a vehicle speed, a lateral acceleration acting on the vehicle, a loaded weight of the vehicle, a torque distribution to front and rear wheels, a grip force of a tire, a vehicle height, a steering angular velocity of a steering wheel, a slope of a road surface or a road surface. Coefficient of friction and the like can be mentioned. Of course, the running state of the vehicle is not limited to these, and may be another type of running state.

Further, the predetermined traveling state of the vehicle does not necessarily have to be one type, and a plurality of types may be appropriately combined. Of course, the control of the turning ratio or the turning phase characteristic based on those factors may be either one or both of the turning ratio characteristic and the turning phase characteristic, and any control pattern may be used. Even if it is something like
For example, the steering of the rear wheels may be in phase only with respect to the front wheels, or may be in only the opposite phase, and is not limited to any particular type.

Also, various configurations can be adopted as the front wheel turning measuring unit and the rear wheel turning angle measuring unit. For example, both left and right wheels may be measured, or only one of the left and right wheels may be measured. It may be something.

(Operation) By using the above-mentioned mounting method and method, by sending a simulation signal, the vehicle is not actually driven into a predetermined traveling state, for example, without traveling at a predetermined speed. The characteristics of the steering angle (for example, the characteristics indicated by a solid line in FIG. 20 when the predetermined traveling state is the vehicle speed) and the steering ratio or the steering ratio of the rear wheels to the front wheels according to the predetermined traveling state. Rudder phase characteristics (for example, FIG. 16 to FIG.
The characteristic shown by the solid line in FIG. 19) can be detected very simply, accurately and quickly, and the result of this detection can be used to determine the characteristic of the steering angle of the rear wheels with respect to the predetermined running state and the predetermined By adjusting the turning means of the rear wheels in comparison with the turning ratio or turning phase characteristics of the rear wheels with respect to the front wheels according to the running state, it is possible to perform accurate adjustment of the four-wheel steering device. Thus, the running stability of the vehicle having the four-wheel steering device can be sufficiently ensured.

Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a plan view schematically showing a four-wheel steering device of a vehicle. This four-wheel steering device uses a vehicle speed sensor as a traveling state detection sensor and outputs a predetermined traveling state signal output from the sensor. Both the steering ratio and the steering phase are variably controlled in accordance with the vehicle speed signal of the front wheel 1.
The front wheels a and 1b are steered by the front wheel turning means 4 in response to the operation of the steering wheel 3, and the rear wheels 2a and 2b are steered by the rear wheel turning means 10. This rear wheel steering means 10
The turning amount of the front wheel turning means 4 is transmitted through the transmission members 5a and 5b, and the turning phase and the turning ratio are variably controlled in accordance with the vehicle speed signal input from the vehicle speed sensor 8. The steering control of the rear wheels 2a and 2b by the rear wheel steering means 10 is performed based on the steering phase and the steering ratio of the vehicle and the transmitted front wheel steering amount, and the four-wheel steering is performed. The transmitting bodies 5a and 5b are connected via a connecting means 6, and the transmitting bodies 5a and 5b are shafts for mechanically transmitting the turning of the front wheels 1a and 1b to the rear wheel turning means 10. Also, front wheels 1a, 1
It may be a cable for transmitting the steering of b as an electric signal.

Here, first, a method of performing a characteristic inspection of the four-wheel steering device will be schematically described. In performing this inspection, the four-wheel steering system employs a vehicle speed signal as a predetermined traveling state signal which is a variable control factor of the steering ratio and the steering phase. Means are used. Of course, a simulated vehicle speed signal is transmitted from the simulated vehicle speed signal transmitting means.
In order to perform this characteristic inspection, first, a simulated vehicle speed signal corresponding to a predetermined vehicle speed signal is transmitted from the simulated vehicle speed signal transmitting unit to the rear wheel steering unit 10 instead of the vehicle speed sensor 8. Then, the user operates the steering wheel 3 to turn the front wheel steering means 4.
The left and right front wheels 1a, 1b are steered by the
Measure the steering angle of 1b. When the front wheels 1a, 1b are steered in this manner, the steering of the front wheels 1a, 1b is transmitted to the rear wheel steering means 10 via the transmission bodies 5a, 5b connected by the connecting means 6, and The steering means 10 steers the rear wheels 2a, 2b according to the steering ratio and the steering phase determined according to the simulated vehicle speed signal and the steering amount of the front wheels 1a, 1b. Two
The steering angles of a and 2b are also measured. Then, the change characteristic of the turning angle of the rear wheels 2a, 2b with respect to the turning angle of the front wheels 1a, 1b is detected by these measurements, and this characteristic is set to a predetermined basic characteristic (the vehicle speed value of the simulated vehicle speed signal). Then, a comparison is made with a preset target characteristic of the steering angle of the rear wheel with respect to the steering angle of the front wheel) to check whether or not the basic characteristic is matched. If the measured characteristics do not match the basic characteristics, the four-wheel steering device is adjusted so as to obtain desired characteristics.

Generally, the four-wheel steering characteristic inspection is performed as described above. Hereinafter, a specific example of a four-wheel steering device will be described, and toe-in adjustment of front and rear wheels in a vehicle having the device and the toe-in adjustment of the device will be described. A specific method and apparatus for performing a characteristic test will be described.

FIG. 2 is a schematic plan view showing an example of the four-wheel steering device. The front wheel turning means 4 includes a front wheel turning rod 4a having a first rack meshing with a first pinion 3a formed at a lower end of the steering wheel 3, tie rods 4b, 4b connected to both ends of the rod 4a, Knuckles 4c, 4c connected to the outer ends of the tie rods 4b, 4b, the front wheel steering rod 4a is moved in the vehicle width direction according to the operation of the steering wheel 3, and this movement is performed via the tie rods 4b, 4b. Knuckle 4c,
4c, the front wheels 1a, 1b are steered. The front wheel steering rod 4a is formed with a second rack that meshes with a second pinion 5c provided at the front end of a rotation transmission shaft (transmission body) 5a, and the front wheel steering rod 4a is operated by operating the steering wheel 3. Is moved in the vehicle width direction, the rotation transmission shaft 5a is simultaneously rotated via the second pinion 5c. This rotation is transmitted to the variable turning ratio mechanism 20 of the rear wheel turning means 10 via the connecting means 6 and the other transmission shaft 5b, and the rear wheels are turned in accordance with the turning phase and the turning ratio adjusted here. The vehicle is steered as described later.

On the other hand, the rear wheel steering means 10 includes a rear wheel steering rod 15 extending in the vehicle width direction, tie rods 16, 16 connected to both ends of the rod 15, and an outer end of the tie rods 16, 16. Knuckles 17 and 17 having a knuckle arm that is provided and rotatably supporting the rear wheels 2a and 2b. The rear wheels 2a and 2b are steered by moving the rear wheel steering rod 15 in the vehicle width direction. . The rear wheel steering rod 15 includes a cylinder 11 that is fixed to the vehicle body and supports the rear wheel steering rod 15 so as to be movable in the vehicle width direction. A hydraulic actuator comprising a fixedly mounted piston 12 slidable in a cylinder 11 and neutral return springs 14a, 14b disposed in left and right hydraulic chambers 13a, 13b divided by the piston 12 is mounted. ing. Hydraulic lines 39a, 39b from a control valve 38 are connected to the left and right hydraulic chambers 13a, 13b of the hydraulic actuator, and the hydraulic actuator is operated by the hydraulic pressure supplied from the control valve 38, whereby the rear wheel steering rod 15 in the vehicle width direction is operated. Is performed, whereby the rear wheels are steered. The hydraulic oil in the tank 35 is supplied to the control valve 38 by being pressurized by the pump 36. The control valve 38 is of a known spool valve type, and has a cylindrical valve housing 38a integrally connected to the rear wheel steering rod 15 via an arm 15a, and is fitted in the valve housing 38a. And a hydraulic chamber 13a of a hydraulic actuator that moves the valve housing 38a together with the rear wheel steering rod 15 following the movement of the spool valve 38b in the vehicle width direction in accordance with the movement of the spool valve 38b in the vehicle width direction. 13b is selectively supplied with hydraulic pressure. That is, by moving the spool valve 38b in the vehicle width direction, the rear wheel steering rod 1 follows the spool valve 38b.
5 is moved and the rear wheels are steered.

The hydraulic lines 39a and 39b are respectively
The valve is connected to a normally closed fail-safe solenoid valve 37 through 7a and 37b.
When the valve 37 is opened by energizing 37c, the hydraulic pressure in both hydraulic chambers 13a, 13b of the hydraulic actuator becomes equal, and the biasing force of the neutral return springs 14a, 14b causes the piston 12 to be positioned at the neutral position, and the rear wheel 2a , 2b is always set to zero, and a fail-safe mechanism for setting the steering characteristics of the vehicle to a two-wheel steering state is operated.

The movement of the spool valve 38b in the vehicle width direction is performed by the variable steering ratio mechanism 20 receiving rotation from the rotation transmission shaft 5b. The variable steering ratio mechanism 20 will be described with reference to FIG. I do. The turning ratio variable mechanism 20 includes a swing arm 22 whose base end is swingably supported by a U-shaped holder 21 via a support pin 22a, and the holder 21 is a casing (not shown) fixed to a vehicle body. The spool valve 38b
And it is rotatably supported via a support shaft 21a having an axis of rotation l ₂ to move the axis l ₁ and orthogonal. The support pin 22a of the swing arm 22 is located at the intersection of the _two axes l ₁ and l ₂ and extends in a direction perpendicular to the rotation axis l _2, and moves the holder 21 around the rotation axis l ₂ of the support shaft 21a. Direct by rotating, angle of inclination and the movement axis l ₁ of the support pins 22a and Supurubarubu 38b at the tip, i.e. the swinging locus plane of the swing arm 22 around the support pin 22a is the moving axis l ₁ to The angle of inclination formed with respect to a plane (hereinafter, referred to as a reference plane) is changed.

Also, one end of a connecting rod 23 is connected to the tip of the swing arm 22 via a ball joint 23a, and the other end of the connecting rod 23 is connected to the other end of a spool valve 38b via a ball joint 23b. The distal end of the swing arm 22 is displaced in the left-right direction in FIG. 3 with the swing of the swing arm 22.

The connecting rod 23 is
A portion near a is slidably supported by the rotation applying arm 24 via a ball joint 23c. The rotation imparting arm 24 is rotatably supported via a support shaft 24a on the moving axis l ₁ made from a large diameter bevel gear, bevel gear on the bevel gear attached to the rear end of the rotation transmitting shaft 5b 5d are meshed with each other to transmit the rotation of the steering wheel 3 to the rotation applying arm 24. Thus, the rotation imparting arm 24 and the connecting rod 23 rotate about the movement axis l _{1 by} an amount corresponding to the rotation angle of the steering wheel 3, and the swing arm 22 swings about the support pin 22a accordingly. If it is, when the axis of the pin 22a is coincident with the axis of movement l ₁ of the spool valve 38b is swing arm 22 tip end of the ball joint 23a is only swung on the reference plane, the spool valve 38b is stationary are held, the swinging locus plane of the swing arm 22 the axis of the pin 22a is inclined relative to the axis of movement l ₁ is displaced from the reference plane, the swinging of the swing arm 22 around the pin 22a The ball joint 23a is displaced in the left-right direction in FIG. 3 with the movement, and this displacement is transmitted to the spool valve 38 via the connecting rod 24.
is transmitted to b, the spool valve 38b is moved along the movement axis l _1. That is, even if the swing angle of the swing arm 22 about the axis of the support pin 22a is the same, the displacement of the spool valve 38b in the left-right direction is caused by the change in the inclination angle of the pin 22a, that is, the change in the rotation angle of the holder 21. It changes with it.

Then, in order to change the rotation angle of the holder 21,
A sector gear 25a as a worm wheel is mounted on the support shaft 21a of the holder 21, and a worm gear 25b is meshed with the sector gear 25a. A bevel gear 25c is mounted on the shaft of the worm gear 25b, and a bevel gear 25d mounted on the output shaft of a stepping motor 26 as an actuator is meshed with the bevel gear 25c to operate the stepping motor 26. By turning the sector gear 25a, the tilt angle of the holder 21 with respect to the reference plane is changed to change the turning angle of the rear wheels 2a, 2b, that is, the turning ratio and the turning phase of the front and rear wheels 1a, 1b, 2a, 2b. Control. Further, a turning ratio sensor comprising a potentiometer as turning ratio detecting means for detecting a turning angle of the sector gear 25a corresponding to an actual turning ratio controlled by the stepping motor 26 is provided on the support shaft 21a of the holder 21. 27 are provided.

Control of the turning ratio and the turning phase by the stepping motor 26 is performed by a controller 33 which receives a vehicle speed signal from a vehicle speed sensor 34 and receives power supply from a battery 31.For example, as shown in FIG. 4, when the vehicle speed is zero, The steering ratio is maximized in the opposite phase. When the vehicle speed is 30 km / H, the two-wheel steering state is achieved at zero phase. When the vehicle speed is 120 km / H, the steering ratio is maximized in the same phase.

Next, an apparatus for inspecting the four-wheel steering characteristics of a vehicle having the above-described four-wheel steering apparatus will be described, and its structure and characteristic inspection method will be described.

FIG. 5 is a plan view showing an inspection device 40 for performing toe-in adjustment and four-wheel steering characteristic inspection.
A front wheel static tester 41 for measuring the toe-in angle and the steering angle of the front wheel; a front wheel guide 43 for guiding the left and right front wheels to the front wheel static tester 41; and a measurement for measuring the toe-in angle and the steering angle of the rear wheel. A wheel static tester 45 and a rear wheel guide 47 for guiding the left and right rear wheels to the rear wheel static tester 45 are arranged in a row as shown in the figure, and transport the vehicle in the direction of arrow A. The front and rear wheels are guarded by front and rear wheel guides 43 and 47, respectively, so as to be positioned on front and rear wheel static testers 41 and 45. The apparatus 40 includes a simulated fail signal transmitting means for transmitting a simulated fail signal to a vehicle to be inspected and a simulated vehicle speed signal transmitting means for transmitting a simulated vehicle speed signal. There is provided a comparison inspection means 100 for comparing the set four-wheel steering characteristics with the preset basic characteristics. For this reason, lines 100a to 100d to which the measured values of the turning angles of the front and rear wheels are input are connected to the comparative inspection means 100, and a line 105b having a connector 105b connected to the controller of the vehicle is connected to the simulation signal sending means 105. Is connected.

FIG. 6 is a front view showing the front wheel static tester 41 in detail along the arrow VI-VI, and FIG. 7 is a detailed plan view of the static tester 41. This static tester 41 is composed of a pair of testers which are symmetrical to the left and right to measure the toe-in angle and the steering angle of the left and right front wheels as can be seen from the figure. Are given the same numbers, and only one of them will be described. The static tester 41 is mounted on a support base 41a, and is a full float type turntable 50 that supports the front wheels so as to be able to steer and move left and right and back and forth, and a tire for a front wheel mounted on the turntable 50. A front wheel angle measuring means 60 for measuring the toe-in angle, the steering angle, etc. of the front wheels by contacting the side surface; and a tester moving means mounted on the support table 41a for moving the front wheel angle measuring means 60 in the vehicle width direction. 70
It is composed of The front wheel angle measuring means 60 has a measuring plate 61 abutting on the tire side surface of the front wheel, and the tester moving means 70
The measurement plate 61 is brought into contact with the side surface of the tire of the front wheel placed on the turntable 50 by the movement by, and the inclination of the measurement plate 61 is measured to measure the toe-in angle and the steering angle. .

Here, the turntable 50 is shown in detail in FIGS. 8 and 9, and the structure of the turntable 50 will be described. The turntable 50 has a frame 51 composed of a plurality of members fixedly mounted on a support 41a.
A plurality of bearings 52 are fixedly arranged on the same circumference on the upper surface of the. This bearing 52 is a rotatable ball 52a
The table 2 is supported by the ball 2a so as to be rotatable and movable back and forth and right and left. This table
Front and rear guides 53a, 53a for positioning the front wheel in the front-rear direction are provided on top of the front wheel 53 for supporting the front wheel. Left and right guide plate 53b for positioning
Is provided. Further, a rotary shaft 54 extending downward from the center of the table 53 is mounted on the table 53, and an encoder 55 for detecting a rotation angle of the table 53 is mounted on a lower end of the rotary shaft 54. The frame 51 has a table
Transfer plate for smooth transfer of front wheels to 53
51b, 51b are attached with the table 53 sandwiched between front and rear. Further, shaft holding plates 56, 56 are provided on the frame 51 so as to oppose the rotating shaft 54 in the front and rear direction and to be movable back and forth, and the shaft holding plates 56, 56 The arm 58 is connected to the upper end of the arm 58 rotatably mounted. The lower end 58c of the arm 58 is connected to both ends of the cylinder 59.
The shaft holding plate 56 is moved back and forth by rotating the shaft 58, and when the cylinder 59 is extended, the two shaft holding plates 56, 56 are moved.
Approach each other and move away from each other when they shrink. FIG. 8A shows these two shaft holding plates 56, 56 and the rotating shaft 54 in a cross-section along arrow VIII-VIII, and as can be seen from this figure, the shaft holding plates 56, 56 are opposed to each other. At the end, a cut 56a in the shape of a right triangle is provided, and a portion 54a of the rotating shaft 54 facing the cut 56a has a square cross section corresponding to the cut. Therefore, when the cylinder 59 is extended and the two shaft holding plates 56, 56 approach, the cuts 56a, 56a
Sandwiches the square portion 54a, and fixes and holds the rotating shaft 54. Therefore, in the above state, the table 53 is also
a is fixed and held in a state where it faces forward and backward.

Next, the front wheel angle measuring means 60 will be described with reference to FIGS.
The structure of the tester moving means 70 will be described. The front wheel angle measuring means 60 extends forward on the frame 65 and has a support shaft 62 attached thereto. The front plate of the support shaft 62 is rotatably connected to a measurement plate 61 via a ball joint 62a.
Is installed. In this state, the measurement plate 61 is rotatable about the ball shore 62a, but is held vertically upright with respect to the frame 65 by a compression spring 63a, a tension spring 63b and a link 63c as shown in the figure. It should be noted that the measurement plate 61 is held in the upright state when no external force acts on the measurement plate 61, and when the measurement plate 61 receives an external force, the springs 63a and 63b bend and the link 63c deforms. The measurement plate 61 is turned around a ball joint 62a in response to an external force. Therefore, when the measurement plate 61 is brought into contact with the front side of the tire of the front wheel, the measurement plate 61 is tilted according to the inclination of the tire. Therefore, if the inclination of the measurement plate is measured, the toe-in angle and the steering angle of the front wheel can be obtained. , Camber angle and the like can be measured. In order to measure the inclination angle of the measuring plate 61, three displacement measuring devices 64 are mounted on the frame 65. This displacement measuring device 64 is a probe 64a that projects forward and is movable back and forth.
As shown in FIG. 12, they are attached to the left, right, and above the ball joint 62a. This probe 64a
Is the measuring plate when the measuring plate 61 is in contact with the side of the tire.
When the measurement plate 61 is inclined, the amount of movement of each probe 64a in the front-rear direction (fore-and-aft movement in the displacement measurement device 64) is provided. amount)
, A toe-in angle, a steering angle, a camber angle, and the like can be detected from the difference. Specifically, the toe-in angle and the steering angle can be measured from the difference in the amount of movement of the probe 64a before and after the probe 64a of the displacement measuring device 64 disposed on the left and right sides of the ball joint 62a. The camber angle can be measured from the displacement of the displacement measuring device 64 disposed above the ball joint 62a. For this reason,
If only the adjustment of the toe-in angle and the measurement of the turning angle are performed as in the present invention, only the two displacement measuring devices 64 arranged depending on the ball joint 62a may be used. The displacement measuring device 64 and the like are provided with a cover 60 as shown by a two-dot chain line in FIG.
Covered by a.

The front wheel angle measuring means 60 having the above configuration is supported by the tester moving means 70 via the frame 65 so as to be movable in the front-rear direction. The structure of the tester moving means 70 and the support of the front wheel angle measuring means 60 by this are Will be described. The tester moving means 70 has a frame 71 fixed on the support table 41a, a pair of left and right guide rods 72, 72 extending back and forth by the frame 71, and
A transport rod 74 extending back and forth between 2,72 is supported. On each guide rod 72, two guide legs 67, 67 fixedly mounted on the lower surface of the frame 65 of the front wheel angle measuring means 60 are slidably fitted respectively, whereby the front wheel angle measuring means 60 The tester moving means 70 supports the front and rear movably. Further, a screw is formed on the outer periphery of the transfer rod 74, and a screw bush 66a of a transfer leg 66 fixed to the lower surface of the frame 65 of the front wheel angle measuring means 60 is screw-engaged with the transfer rod 74. I have. Transfer rod 74 is frame 71
The first sprocket 75a attached to the end of the motor is rotatably supported by the
A second sprocket 75c mounted on the shaft of 76 is engaged with the second sprocket 75c, and by rotating the motor 76 to rotate the transport rod 74, the front wheel speed measuring means 60
The whole can be moved back and forth. In order to set the front and rear movement positions at this time, the frame 71 of the tester moving means 70 is used.
Are mounted with two limit switches 73, 73 which are spaced apart in the front-rear direction.
A pair of switch plates 68, 68 facing the limit switch 73 are attached to the 65, and the drive of the motor 76 is controlled by the operation of the limit switch 73 by the contact between the switch plate 68 and the limit switch 73, and the front wheel Angle measuring means
The movement positioning before and after 60 is performed.

Although the front wheel static tester 41 has been described above, the rear wheel static tester 45 will be described next. Similarly to the front wheel static tester 41, the rear wheel static tester 45 also includes a pair of left and right testers, and each tester includes a full float turntable 150, a rear wheel angle measuring unit 160, and a tester moving unit 170. I have. 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 right and left. These are slightly different in shape from the front wheel turntable 50, but their functions and essential structures are the same, and therefore description thereof is omitted. On the other hand, the rotating shaft 154 extending downward from the table 153 has a smaller amount of downward extension than the rotating shaft 54 of the front wheel table 53, and has a square cross section 154a at its lower end. Is not installed. This is because the steered angle of the front wheels is large in a four-wheel steered vehicle,
Since the steering angle cannot be measured with only 60, the steering angle in the range of ± 5 ° around the straight traveling direction is measured with high accuracy by the front wheel angle measuring means 60. Is measured by the encoder 55. However, since the turning angle of the rear wheel is within ± 5 ° with respect to the straight traveling direction as the center, it can be sufficiently measured only by the rear wheel angle measuring means 160. This is because it can be done. In addition, a pair of shaft holding plates 156,156
The two shaft holding plates 156, 156 are normally expanded by a spring 157, but are pushed by the cylinders 158, 158 arranged in front and rear, and are held by the two holding plates 156, 156.
The rotation shaft 154 is fixedly held by the square cross section 154a being clamped. A rear wheel angle measuring means 160 for measuring a toe-in angle, a turning angle, and the like of the rear wheel, and the rear wheel angle measuring means 160 is mounted in a vehicle width direction (lateral direction).
The tester moving means 170 for moving the front wheel static tester 41 has the same function and structure as that of the front wheel static tester 41, and therefore, the description thereof is omitted.

Next, the front wheel guide 43 and the rear wheel guide 47 that guide the front wheel and the rear wheel to the front wheel static tester 41 and the rear wheel static tester 45, respectively, will be described. Since these two guides 43, 47 have the same shape, the front wheel guide 43 is shown in FIG. The front wheel guide 43 has a pair of guides 90, 90 each having a guide groove 90a for guiding the left and right front wheels toward the static tester 41, and these guides 90, 90 are arranged in the vehicle width direction (lateral direction). ). Further, a guide plate 9 opened in a "C" shape toward the rear to correctly guide the front wheel to the guide groove 90a.
1,91 are installed. A rotatable first arm 92a and a second arm 92b extending rightward in the drawing are attached to frames 96, 97 facing the outer side surfaces of the two guide bodies 90, 90, and both arms 92a, 92b. Are connected by a first connecting rod 93. The first arm 92a is connected to a guide body 90 supporting the right front wheel by a second connecting rod 95 as shown in the figure, and a second arm 92b is attached to a frame 97 facing the outer surface of the guide body 90 supporting the left front wheel. A third arm 92c extending forward (to the left in the drawing) from the mounting portion of the second arm 92b is rotatably mounted integrally with the second arm 92b.
Is connected to a guide body 90 supporting the left front wheel by a third connecting rod 94 as shown. For this reason, if the first connecting rod 93 is moved in the vehicle width direction by a cylinder (not shown) or the like, the two guide bodies 90 can be moved in opposite directions in the vehicle width direction. Even if the tread is different, both guides 9 according to this tread
The distance of 0,90 can be adjusted.

Further, lifters 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. 5, the lifter includes a frame 106 and a cylinder 102 fixed to the frame 106 and extending vertically. The rod 101 can freely protrude upward, and a head 101a having a groove 101b is attached to the upper end thereof. 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 respectively mounted on a full float type turntable, when an external force is applied to the vehicle body in the horizontal direction, the turntable is moved and the vehicle body is moved, and the measurement by the front wheel and rear wheel angle measuring means is inaccurate. However, by lifting and supporting the vehicle body by the lifter, the vehicle body can be prevented from being moved even when a horizontal external force is applied to the vehicle body. Furthermore, by lifting the vehicle body by the lifter, the weight of the vehicle body applied to the tire placed on the turntable can be reduced, thereby reducing the deformation of the tire and reducing the load on the turntable. It is made smaller so that the turntable can rotate smoothly.

A method for inspecting the four-wheel steering characteristics of a vehicle equipped with a four-wheel steering device using the above-described inspection device 40 will be described second.
The four-wheel steering vehicle shown in the figure will be described as an example. First,
After the cylinders 59, 158, 158 of the front wheel turntable 50 and the rear wheel turntable 150 are extended and the rotating shafts 54, 154 are fixed and held by the shaft holding plates 56, 56 and 156, 156, the device 40 is placed on the right side in FIG. The vehicle is transported in the direction of arrow A, and the front wheels 1a, 1b and the rear wheels 2a, 2b are placed on the front and rear static testers 41, 45 by the front and rear wheel guides 43, 47, respectively. Next, the heads 101a of the lifters 48 and 49 are moved up to move the heads 101a.
By lifting the side sill portion of the vehicle body by a, the load on the turntables 50 and 150 from the front and rear wheels is reduced, and the vehicle body is held and the horizontal movement of the vehicle body due to external force is prevented. The lifting force of the vehicle body by the lifters 48, 49 is set such that a load enough to rotate the tables 53, 153 smoothly according to the turning of the front wheels and the rear wheels is left on the tables 53, 153. Next, the cylinders 59, 158, 158 of the front wheel turntable 50 and the rear wheel turntable 150 are contracted to release the fixed holding of the rotating shafts 54, 154 by the shaft holding plates 56, 56 and 156, 156, thereby bringing the tables 53, 153 into a full float state.

From this state, first, toe-in adjustment of the front wheels and the rear wheels is performed. This toe-in adjustment is performed separately for the front and rear wheels in a state where the connection of the front wheel and rear wheel steering means 4 and 10 by the connection means 6 is released. In this case, the toe-in angle is measured by the angle measuring means 60, 160 of the front and rear wheel static testers 41, 45, and the toe-in angle when the front and rear wheels are oriented straight and the steering wheel is oriented horizontally is a predetermined value. After that, the front wheel and the rear wheel turning means are connected by the connecting means 6, but the description of the specific adjusting method is omitted. The toe-in adjustment here includes not only so-called wheel toe-in adjustment but also adjustment in the toe-out direction.

After the toe-in adjustment, an inspection of the four-wheel steering characteristics is performed. The inspection of the four-wheel steering characteristic is performed by measuring and measuring the relationship between the turning angles of the front wheels 1a and 1b and the turning angles of the rear wheels 2a and 2b accompanying the operation of the steering wheel 3 with the change in the vehicle side. The specific inspection method is described below.

First, a method for checking the operation of a fail-safe mechanism, which is an example of the method of the present invention, will be described. For this inspection, first, the steering wheel 3 is largely steered in either the left or right direction, and the front wheels and the rear wheels are steered as much as possible. For this purpose, a simulated vehicle speed signal (for example, a vehicle speed of 0 km / H or 120 km / H) in which the front wheels are steered to the maximum steering angle and the steering angles of the rear wheels are also maximized.
Is transmitted to the controller 33. The simulated vehicle speed signal is transmitted by connecting the connector 105b of the simulated signal transmitting means 105 to the controller 33 instead of the vehicle-side sensor 34 of the vehicle to be inspected, and from the simulated signal transmitting means 105 via the line 105a. Controller for vehicle speed signal
This is done by sending to 33. At this time, the turning angles of the front wheels and the rear wheels are measured by the front and rear static testers 41 and 45. In this case, the front wheel is steered beyond the measurement range of the front wheel angle measuring means 60, and the encoder 55 attached to the lower end of the rotating shaft 54 of the turntable 50 is used.
The steering angle is measured by the
The turning angle is measured by 160.

Next, the solenoid 37c of the fail-safe solenoid valve 37 in the rear-wheel steering means 10 of the four-wheel steering vehicle is energized to open the solenoid valve 37. That is, the fail-safe mechanism is operated. In this case,
A simulated fail signal is sent from the simulated signal sending means 105 connected to the controller 33 to the controller 33, and the solenoid valve 37 is opened by the controller 33.
When the solenoid valve 37 is opened, as described above, the hydraulic pressures in the hydraulic chambers 13a and 13b of the hydraulic actuator become equal, and the piston 12 is moved to the neutral position by the biasing force of the neutral return springs 14a and 14b. Since the wheels are to be in a straight running state (the steering angle is zero), this is detected by the rear wheel angle measuring means 160, and the comparison inspection means 100 receiving this detection signal outputs the signal to the front wheel steering angle. Whether the characteristic of the rear wheel turning angle matches a preset basic characteristic, that is, the characteristic that the rear wheel turning angle is zero for all front wheel turning angles, that is, whether the fail-safe mechanism is operating Check for no.

Next, an example of another inspection method according to the present invention will be described. For this inspection, the steering wheel 3 is reciprocated right and left around the horizontal direction, and the front wheels 1a, 1b
Is reciprocally steered within a predetermined range around the straight traveling direction. In this case, the front wheel steering angle range may be a small range, for example, about ± 3 ° in this example. Since the rear wheels 2a and 2b are also steered by the steering of the front wheels, the steering angle of the front and rear wheels at this time is measured and a characteristic test is performed. It is preferable to input a simulated vehicle speed signal at which the steering ratio becomes maximum to the controller 33 so that the rudder can be easily measured. For this reason, the connector 105b of the simulation signal transmitting means 105 is connected to the controller 33 instead of the vehicle speed sensor of the vehicle to be inspected, and the simulation vehicle speed for maximizing the steering ratio from the simulation signal transmitting means 105 via the line 105a. A signal (vehicle speed signal corresponding to a vehicle speed of 0 km / H or 120 km / H) is transmitted to the controller 33.

The steering angles of the front wheels and the rear wheels when the front wheels are steered by operating the steering wheel under the above conditions are determined by angle measuring means 60 of the front and rear static testers 41 and 45.
Measure according to 160. An example of this measurement result is shown by showing the rear wheel turning angle on the vertical axis and the front wheel turning angle on the horizontal axis.
As shown by the solid line in the graph of FIG. 16, a locus having a constant hysteresis is obtained. The trajectory having hysteresis is obtained as described above because there is a backlash in the connection system between the front wheel turning means and the rear wheel turning means. In this case, if the adjustment of the rear wheel steering angle when the front wheel steering angle is zero is adjusted based on one of the rightward and leftward steering of the front wheel, the steering in the other direction is performed. Since the steering angle of the rear wheels is deviated and running stability is impaired, in the present invention, in the comparative inspection means 100 receiving the above measurement signal, the curve β representing the midpoint of both trajectories is set to the origin on the graph. (I.e., whether or not the trajectory curve obtained by turning rightward and the trajectory curve obtained by turning leftward are substantially point-symmetric about the origin), that is, the curve β Is checked to see if it meets the basic characteristic of passing through the origin on the graph set in advance. 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 means shown in FIGS. 2 and 3, since the neutral return springs 14a and 14b are pre-compressed, the rear wheels 2a and 2b are moved to the straight traveling position (the steering angle is When turning in the left or right direction from the zero position, the dead zone where the rear wheel is not steered with respect to the steering of the front wheel (the trajectory curve is almost in the vicinity of the front wheel turning angle of zero in the graph). Horizontal portion). Therefore, for example, the front wheel turning angles α ₁ and α ₂ at the time when this dead zone occurs are read, and it is determined whether or not the median of both turning angles α ₁ and α ₂ is zero (that is, both dead zones are centered on the origin). (Ie, whether or not point symmetry is obtained), that is, whether or not the above α ₁ and α ₂ match the basic characteristic that the median of α ₁ and α ₂ is zero. You may do so.

Further, a third example of the method for inspecting the four-wheel steering characteristics according to the method of the present invention will be described below. First,
A simulated vehicle speed signal (for example, a vehicle speed signal corresponding to a vehicle speed of 120 km / H) is transmitted from the simulated signal transmitting means 105 to the controller 33 via the line 105a so as to make the turning phase the same and to maximize the turning ratio. . When the front wheels 1a and 1b are steered by operating the steering wheel 3 in this state, the rear wheels 2a and 2b are also steered in the same phase, so that the steering angles of these front and rear wheels are adjusted by the front and rear static testers 41. , 45 angle measuring means 60,
Measure according to 160. FIG. 17 is a graph showing an example of the relationship between the front wheel turning angle and the rear wheel turning angle measured in this way. In this graph, the vertical axis indicates the rear wheel steering angle, the horizontal axis indicates the front wheel steering angle, and the upper side of the vertical axis and the right side of the horizontal axis indicate the rightward steering of the rear wheel and the front wheel. ing. As can be seen from this graph, when the front wheel is steered to the right, the rear wheel is steered to the right accordingly (steered to the same phase). change becomes gradually smaller predetermined steering angle (right maximum steering angle) theta ₁ or more is not steered. The same applies to the case where steered front wheels to the left, the rear wheel is steered while gradually reducing the change and to the left maximum steering angle theta ₂ in the same phase.

Next, a simulated vehicle speed signal (for example, a vehicle speed signal corresponding to a vehicle speed of 30 km / H) is sent from the simulated signal sending means 105 to the controller 33 via the line 105a so as to make the turning phase zero. Even if the front wheels 1a, 1b are steered by operating the steering wheel 3 in this state, the rear wheels 2a, 2b should be maintained at zero phase and not steered. The turning angles of these front and rear wheels are measured by the angle measuring means 60, 160 of the front and rear static testers 41, 45, and show an example of the relationship between the front wheel turning angle and the rear wheel turning angle thus measured. Is the 18th
It is a graph of a figure. As can be seen from this graph, even if the front wheels are steered to the left or right, the rear wheels are hardly steered, and only slight steering θ ₁ and θ ₂ due to dimensional errors and the like occur.

Further, a simulated vehicle speed signal (for example, a vehicle speed signal corresponding to a vehicle speed of 0 km / H) that reverses the turning phase and maximizes the turning ratio is sent from the simulation signal transmitting means 105 to the controller 33 via the line 105a. Send out. When the front wheels 1a, 1b are steered by operating the steering wheel 3 in this state, the rear wheels 2a, 2b are steered in opposite phases, so that the steered angles of these front and rear wheels are adjusted by the front and rear static testers 41. , 45 by the angle measuring means 60, 160. FIG. 19 is a graph showing an example of the relationship between the front wheel turning angle and the rear wheel turning angle thus measured. As can be seen from this graph, when the front wheel is steered to the right, the rear wheel is steered to the left accordingly (steered to the opposite phase). It changes gradually smaller predetermined steering angle (left maximum steering angle) theta ₁ or more is not steered. The same applies to the case where the front wheels are steered to the left, and the rear wheels are in opposite phase and the right-hand maximum steering angle θ ₂
Until the change is gradually reduced until the steering.

When various simulated vehicle speed signals measured as described above are input, desired basic characteristics are set in advance for each of the characteristics of the rear wheel turning angle change corresponding to the front wheel turning angle. The comparison and inspection means 100 compares the characteristic obtained by the measurement with the basic characteristic, and determines whether the measured characteristic is within the required range of the basic characteristic, and sets the maximum turning angles θ ₁ and θ ₂ to a preset basic characteristic. It is checked whether the characteristic is within a predetermined range. If the characteristic does not fall within the predetermined range, that is, if the characteristic does not match the basic characteristic, the turning characteristic is adjusted to match the basic characteristic.

Further, still another example of the method for inspecting the four-wheel steering characteristics according to the present invention will be described. In this method, after the steering wheels 3 are operated to steer the front wheels 1a and 1b largely (preferably to the maximum steering angle), the simulation signal sending means 105 sends the signals to the controller 33 via the line 105a. A simulated vehicle speed signal that gradually changes the vehicle speed, for example, a signal corresponding to a vehicle speed that gradually increases from a vehicle speed of 0 km / H to a vehicle speed of 120 km / H is transmitted. Then, the rear wheel turning angle at this time is measured by the angle measuring means 160 of the rear wheel static tester 45. FIG. 20 is a graph showing an example of the relationship between the rear wheel turning angle measured in this way and the vehicle speed (simulated vehicle speed signal). In this graph,
The vertical axis indicates the rear wheel steering angle, and the horizontal axis indicates the vehicle speed.As can be seen from this graph, when the vehicle speed is zero, the rear wheels are steered to the opposite phase with respect to the front wheels. The maximum turning angle is 5 °, and when the vehicle speed is increased from this state, the turning angle of the rear wheels gradually decreases, and at a vehicle speed of 30 km / H, the turning angle of the rear wheels becomes zero, that is, a two-wheel steering state. When the vehicle speed further increases, the rear wheels are turned to the same phase side, and the amount of turning to the same phase side increases as the vehicle speed increases, but the rate of increase gradually decreases. At a vehicle speed of 120 km / H, the value is 5 ゜. Desired basic characteristics are set in advance for the characteristics of the rear wheel turning angle change with respect to the vehicle speed change under the predetermined front wheel turning angle measured in this way, Is compared with the basic characteristics to determine whether the measured characteristics are within the required range of the basic characteristics. If not, that is, if the measured characteristics do not conform to the above basic characteristics, the steering is performed so as to conform to the basic characteristics. Adjustment of characteristics is performed.

In the above-described embodiment, the four-wheel steering device that variably controls the turning ratio and the turning phase according to the vehicle speed is an object to be inspected. It is also possible to target a four-wheel steering device that variably controls the turning ratio or the turning phase based on the running state of the vehicle, in which case, instead of the simulated vehicle speed signal transmitting means, the predetermined running state Means for transmitting a simulation signal may be used.

(Effects of the Invention) As described above, according to the present invention, the turning of the rear wheels of a four-wheel steering device in which the turning angle of the rear wheels is variably controlled according to a predetermined running state of the vehicle such as the vehicle speed. Claim 1
And the characteristic of the steering angle of the rear wheel with respect to the predetermined traveling state (for example, the characteristic of the steering angle of the rear wheel with respect to the vehicle speed as shown in FIG. 20) and the characteristic described in claim 2. Steering ratio or steering phase characteristic of the rear wheel with respect to the front wheel according to a predetermined traveling state (for example, steering of the rear wheel with respect to the front wheel when the vehicle speed is a specific value as shown in FIGS. 16 to 19) Ratio or steering phase characteristic) is checked using a simulation signal indicating the predetermined running state, so that the vehicle is not actually driven to the predetermined running state, but is extremely simply, accurately, and quickly. Inspection can be performed, and by adjusting the rear wheel steering means based on the inspection, it becomes possible to perform accurate adjustment of the four-wheel steering device, and the running stability of the vehicle having the four-wheel steering device can be improved. Can be fully guaranteed That.

[Brief description of the drawings]

1 is a plan view schematically showing a four-wheel device of a vehicle, FIG. 2 is a schematic plan view of the four-wheel steering device, FIG. 3 is a schematic perspective view showing a turning ratio variable mechanism, FIG. Is a graph showing the relationship between the vehicle speed and the steering angle, FIG. 5 is a plan view showing the inspection device, FIGS. 6 and 7 are front and plan views of the front wheel static tester, and FIGS. 8 and 9 are FIG. 8A is a cross-sectional view showing the turntable along the arrow VIII-VIII, and FIG. 10 to FIG. 12 are front wheel angle measuring means and tester moving means. FIG. 13 is a front view showing a rear wheel turntable, FIG. 14 is a plan view showing a front wheel guide, FIG. 15 is a cross-sectional view showing a lifter, and FIG. FIG. 19 is a graph showing an example of a measurement result of a change in rear wheel turning angle with respect to front wheel turning. FIG. 20 is a graph showing an example of a measurement result of a change in rear wheel turning angle with respect to a change in vehicle speed. 1a, 1b front wheel, 2a, 2b rear wheel 4 front wheel steering means 10, rear wheel steering means 20 variable steering ratio mechanism 34 traveling state detection sensor (vehicle speed sensor) 40 ... Inspection device, 60 ... Front wheel angle measurement means 100 ... Comparative inspection means 105 ... Simulation signal sending means 160 ... Rear wheel angle measurement means

Claims (5)

(57) [Claims] A front wheel steering means for steering a front wheel;
A predetermined traveling state signal is received from a traveling state detection sensor that detects a predetermined traveling state of the vehicle, and the rear wheels are steered based on a characteristic of a rear wheel turning angle with respect to the predetermined traveling state that is set in advance. A four-wheel steering device for a vehicle having a four-wheel steering device comprising a rear-wheel steering device to be driven, a rear-wheel steering angle measuring device for measuring a rear-wheel steering angle, and the rear-wheel steering device Simulation signal transmitting means for outputting a simulation signal of the predetermined traveling state signal to the vehicle, and detecting characteristics of a turning angle of a rear wheel with respect to a predetermined traveling state based on the simulation signal when the simulation signal is transmitted. A four-wheel steering characteristic inspection device for a vehicle, comprising: comparison inspection means for comparing and comparing the characteristic with the characteristic of the steering angle of the rear wheel with respect to the preset predetermined traveling state. 2. Front wheel steering means for steering a front wheel;
A predetermined traveling state signal is received from a traveling state detection sensor that detects a predetermined traveling state of the vehicle. According to the predetermined traveling state signal, a steering ratio or a steering phase characteristic of a rear wheel with respect to a front wheel is variably controlled and the front wheel is controlled. An apparatus for inspecting a four-wheel steering characteristic of a vehicle having a four-wheel steering device including a rear-wheel steering means for steering a rear wheel based on a steering ratio or a steering phase characteristic of a rear wheel, comprising: Front wheel turning angle measuring means for measuring the turning angle of the rear wheel, rear wheel turning angle measuring means for measuring the turning angle of the rear wheel, and a simulation signal of the predetermined traveling state signal to the rear wheel turning means. Simulation signal transmitting means, detecting a steering ratio or a steering phase characteristic of the rear wheel with respect to the front wheel when the simulation signal is transmitted, and setting the characteristic in advance in correspondence with a predetermined running state by the simulation signal. Of the rear wheels with respect to the front wheels A four-wheel steering characteristic inspection device for a vehicle, comprising: comparison inspection means for comparing and comparing the steering ratio or the steering phase characteristic. 3. The vehicle according to claim 1, wherein the predetermined traveling state of the vehicle is at least one of a vehicle speed, a steering angular speed, a lateral acceleration acting on the vehicle, and a slope of a road surface. 4 wheel steering characteristics inspection device. 4. A front wheel steering means for steering a front wheel;
A predetermined traveling state signal is received from a traveling state detection sensor that detects a predetermined traveling state of the vehicle, and the rear wheels are steered based on a characteristic of a rear wheel turning angle with respect to the predetermined traveling state that is set in advance. A method for inspecting the four-wheel steering characteristics of a vehicle having a four-wheel steering device comprising a rear-wheel steering device to be driven, comprising: sending a simulation signal of the predetermined traveling state signal to the rear-wheel steering device; The turning angle of the rear wheel is measured, and the characteristic of the turning angle of the rear wheel with respect to a predetermined running state based on the simulation signal obtained by the measurement is changed to the predetermined value of the rear wheel turning with respect to the predetermined running state. A method for inspecting four-wheel steering characteristics of a vehicle, wherein an inspection of four-wheel steering characteristics is performed in comparison with characteristics of a steering angle. 5. The vehicle according to claim 4, wherein the predetermined running state of the vehicle is at least one of a vehicle speed, a steering angular velocity of a steering wheel, a lateral acceleration acting on the vehicle, and a slope of a road surface. Wheel steering characteristics inspection method.