JPS63200037A - Apparatus for inspecting four-wheel steering characteristic of automobile - Google Patents

Abstract

PURPOSE:To reduce the error of a measured value, by reducing the ground contact pressure of the tires of front and rear wheels by raising an automobile body by a lifter. CONSTITUTION:Lifters 48, 49 raising an automobile body to support the same are arranged to the front and rear of a front wheel guide and each of them consists of frames 105 and the cylinder 102 extending up and down fixed to the frames 105 and the rod 101 of the cylinder 102 freely protrudes upward and a head 101a having a groove 101b is mounted to the upper end of the rod 101. Therefore, the rod 101 of the cylinder 102 is extended upward. The groove 101b of the head 101a receives the side sill of the automobile body to raise the same. Therefore, by supporting the automobile body so as to raise the same by the lifter, even when external force in a horizontal direction is applied to the car body, the movement of the automobile body can be prevented. Further, the wt. of the automobile body added to tires can be reduced and the deformation of the tires becomes small and, in measuring a steering angle by a touch type sensor, the error of a measured value can be reduced.

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention enables the rear wheels to be steered in response to the front wheels being steered by operating the steering wheel4.
The present invention relates to a vehicle having a wheel steering system, and more specifically to a device for inspecting the characteristics of this four-wheel steering system.

(Prior technology) Conventional four-wheeled vehicles have been steered by steering only the front wheels using the steering wheel. Problems have been pointed out in terms of maneuverability and steering, such as the radius being limited and small turns not being effective.
has been proposed and researched.

With a four-wheel steering system, to help drive at relatively high speeds, if the rear wheels are steered in the same direction as the front wheels (this is called in-phase steering), the front and rear wheels can be steered in the same direction. Since a lateral force is applied, 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 steering direction of the 11η 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, we have provided a mechanism that can arbitrarily variably control the ratio of the steering angle of the rear wheels to the steering angle of the front wheels, that is, the steering ratio, and adjust the steering ratio according to vehicle speed, front wheel steering angle, etc. It has been proposed to perform variable control to improve maneuverability, driving stability, etc. For example, as disclosed in Japanese Unexamined Patent Publication No. 61-108070, there is a four-wheel steering device that variably controls the steering phase and steering ratio depending on the vehicle speed.

In conventional vehicles where only two wheels are steered, the front wheels are steered proportionally to the operation of the steering wheel, so it would have been better to adjust the horizontal position of the steering wheel and the straight direction of the front wheels. In a four-wheel steering system, the front wheels are steered proportionally in response to steering wheel operations, but the rear wheels are steered based on steering characteristics determined by the front wheel's steering angle and medium speed. As before,
There is a problem in that the steering characteristics of the rear wheels relative to the front wheels are insufficiently inspected by making only these adjustments, and the running stability of the vehicle cannot be sufficiently guaranteed if left as is. Therefore, the present applicant measured the steering angles of the front wheels and the rear wheels to examine the steering characteristics of the rear wheels relative to the steering of the front wheels, and in particular the steering characteristics of the four-wheel steering system. Inspection equipment d that allows
and h method are proposed.

(Problem to be solved by the invention) In this case, use A3 to measure the steering angles of the front wheels and rear wheels.
To do this, place the front wheel J3 and the rear wheel on rotatable turntables, operate the steering wheel to steer the front wheels, and calculate the steering angle d3 of this one front wheel and the steering angle of the front wheel. The steering characteristics of the rear wheels relative to the front wheels are measured and inspected by measuring the steering angle of the wheels that are steered accordingly. deforms due to the weight of the car body,
There is a problem in that this deformation becomes large due to the lateral load caused by the steering when the wheels are turned, and there is a possibility that an error in measuring the steering angle may occur. In addition, when measuring the turning angle described above using a touch-type sensor that detects the turning angle of the wheel by coming into contact with the side of the tire, the measured value of this touch-type sensor is not affected by the deformation of the tire. There is the problem of receiving it. Furthermore, the turntable is connected to the vehicle body TFI via the wheels.
There is a problem in that by receiving all m, the load on the turntable rotation support section increases, and the force required to rotate the turntable also increases.

(Means for Solving the Problems) In view of the problem of deformation due to the heavy weight of tires placed on a turntable as described above, the present invention provides an inspection device that can reduce the load applied to tires. In order to solve the above problem, the inspection apparatus of the present invention is constructed as follows. Zunawara,
This device consists of a front wheel turntable in which the left and right front wheels are each supported in a freely steerable manner, a rear wheel turntable in which the right 1 variable wheel is supported in a freely steerable manner, and a turntable for controlling the steering angle of the front wheels. A front wheel steering angle measuring means for measuring the steering angle of the rear wheels, a rear wheel steering angle measuring means for measuring the steering angle of the rear wheels, a front wheel turntable and a rear wheel turntable each having a rear wheel 111 on the left side of the vehicle. The vehicle body is held in this state, and a lifter is used to raise the vehicle body.The lifter is configured to lift the vehicle body in the F direction, thereby reducing the ground contact force of the tie + XI of the front and rear wheels. .

(Function) When using the inspection device having the above configuration, when turning the front and rear wheels in order to inspect the four-wheel steering characteristics of the vehicle, the ground contact force of the front and rear wheels to the turntable, that is, the front wheel J
Since the vehicle body ω that is applied to the turntable from 3 and the rear wheels is light, the amount of deformation of the front and rear tires is small, and the deformation of the tires during steering is also reduced. Therefore, when measuring the steering angle using the touch pin sensor, this sensor is less affected by the deformation of the tire, and the error in the measured value is also reduced. Furthermore, since the load on the turntable is small, the force required to rotate the turntable is light, and the above-mentioned steering can be carried out smoothly.

(Embodiments) Hereinafter, preferred embodiments of the present invention will be described based on the drawings.

FIG. 1 is a plan view schematically showing a four-wheel steering system for a vehicle, in which front wheels 1a and lb are steered by a front wheel steering means 4 according to the operation of a steering wheel 3, and rear wheels 2a and 2b are steered by a front wheel steering means 4 according to the operation of a steering wheel 3.
is steered by rear wheel steering means 10. The steering ω of the front wheel steering means 4 is transmitted to the rear wheel steering means 10 via transmission bodies 5a and 5b, and the steering phase and steering ratio are adjusted according to the amount of steering and the vehicle speed. variable controlled,
Based on these steering phases and steering ratios, the rear wheels 2a and 2b are controlled to be steered by the rear wheel steering means 10, so that four-wheel steering is performed. Note that the Buddha jt bodies 5a and 5b are connected via a connecting means 6, but this Buddha jt body 5a and
, 5b may be a shaft for mechanically transmitting the steering of the front wheels la, I11 to the rear wheel steering means 10, or may be a cable for transmitting the steering of the front wheels 1a, 1b as an electrical signal. Mono-C is also good.

First, a method for testing the characteristics of the four-wheel steering system will be schematically explained. To perform this characteristic test, first, the front wheels 1a, lb and the rear wheels 2a, 2b are respectively placed on a rotatable turntable, and the vehicle body is lifted by a lifter. At this time, the lifting force of the screw lid is such that each wheel does not separate from the turntable, and sufficient ground contact force is secured to rotate the turntable as each wheel is steered, while at the same time ensuring that the VJ weight applied from the wheels to the turntable is sufficient. It is desirable to make it as small as possible. After this, operate the steering wheel and
C+) ij wheel is steered, and at the same time this front wheel 1a,
Measure the steering angle of 1b2. In this way, the front wheel la,
When Ib is steered, the steering of the front wheels 1a and lb is transmitted to the double-wheel steering means 10 via the transmission bodies 5a and 5b connected by the coupling means 6, and the rear wheel steering means 10 steers the front wheels 1a and 1b. , lb, the rear wheels 2a, 2b are steered in accordance with the amount of steering of the vehicle, the vehicle speed, etc., so the steering angles of the rear wheels 2a, 2b at this time are also measured. Based on these measurements, the front wheels 1a, 1
The change characteristic of the turning angle of the rear wheels 2a, 2b with respect to the turning angle of wheel b is detected, and this characteristic is compared and contrasted with a preset basic characteristic, and it is examined whether or not it matches this basic characteristic. . Note that if the measured characteristics do not match the basic characteristics, the four-wheel steering system is adjusted so that the desired characteristics are achieved.

Generally speaking, characteristic tests are carried out as described above, but below we will discuss a specific example of a four-wheel steering system, as well as the toe-in adjustment of the front wheels in a vehicle that is in this l'A position, and the use of this system. A specific method and apparatus for testing characteristics will be explained.

FIG. 2 is a schematic plan view showing an example of a four-wheel steering device.

The front wheel steering means 4 includes a front wheel steering rod 4a having a first rack that meshes with a first pinion 3a formed at the lower end of the steering wheel 3, a tie [1 rod 4b] connected to both ends of this rod 4a, 4b and tie rod 4b, 4
Consisting of knuckles 4C, 4C connected to the outer end of b,
The front wheel steering rod 4a is moved in the Qi width direction in response to the operation of the steering wheel 3, and this movement causes the tie rod 4 to move in the Qi width direction.
b, 4b to knuckles 4C, 4c and front wheel 1
a, lb are steered. In addition, a second rack is formed on the one-wheel steering rod 4a and engages with a second pinion 50 provided at the front end of the rotation transmission shaft (transmission body) 5a, and the front wheels are rotated by operating the steering wheel 3. When the rudder rod 4a is moved in the Φ width direction, the rotation transmission shaft 5a is simultaneously rotated via the second pinion 5C. This rotation is transmitted to the variable steering ratio mechanism 20 of the rear wheel steering means 10 via the coupling means 6 and the other transmission shaft 5b.
In accordance with the steering phase and steering ratio adjusted here, the rear wheels are steered as described below.

On the other hand, the rear wheel steering means 10 includes a rear wheel steering rod 15 extending in the vehicle width direction, a tie rod 16.16 connected to both ends of the rod 15, and a tie rod 16.1.
a rear wheel 2a having a knuckle arm connected to the outer end of the rear wheel 2a;
The knuckle 17°17 supports the rear wheel 2b in a steerable manner, and the movement of the rear wheel steering rod 15 in the width direction of the vehicle steers the rear wheel 2b.
A and 2b are steered. 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, and a cylinder 11 that divides the inner space of the cylinder 11 into two.
A piston 12 is fixedly attached to the cylinder 5 and is slidable inside the cylinder 11.
A neutral return spring 14a is disposed within the left and right hydraulic chambers 13a and 13b which are divided into C-divided sections by the piston 12.
, 14b, etc. are attached. The left and right hydraulic chambers 13a, 1 of this hydraulic actuator
3b is the hydraulic line 39 from the control valve 38.
a, 39b are connected, and the control valve 38
The hydraulic actuator is actuated by the hydraulic pressure supplied from the tank 35, and the rear wheel steering rod 15 is moved in the vehicle width direction, thereby steering the rear wheels. Oil is supplied under pressure by a pump 36. This control valve 38 is
A cylindrical valve housing 38a, which is composed of a known spool valve type, is integrally connected to the rear wheel steering rod 15 via an arm 15a, and a spool valve fitted into the valve housing 38a. 38b, and follows the movement of the spool valve 313b in the vehicle width direction, and moves the valve housing 38a together with the rear wheel steering. Hydraulic pressure is selectively supplied and controlled. In other words, by moving the spool valve 38b in the vehicle width direction, this spool valve 38
The rear wheel steering rod 15 is moved in accordance with b, and the rear wheels are steered.

The hydraulic lines 39a and 39b are connected to a normally closed failloaf solenoid valve 31 via hydraulic lines 37a and 37b, respectively, and the solenoid 37c of this valve 31 is energized to open the valve 3.
7 to rlN, the hydraulic pressures in both hydraulic pressures 7ii13a and 13b of the hydraulic actuator become equal, and the biasing force of the neutral return springs 14a and 14b positions the piston 12 at the neutral position, and the turning angle of the rear wheels 2a and 2b is changed. A fail-safe mechanism is activated that always sets the value to zero and sets the vehicle's steering characteristics to a two-wheel steering state.

The movement of the spool valve 38b in the vehicle width direction is caused by the variable steering ratio mechanism 20 receiving rotation from the rotation transmission shaft 5b.
The variable steering ratio mechanism 2
0 will be explained using FIG. This steering ratio variable mechanism 2
0 includes a 1" IJ first 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 the vehicle body.
The axis of movement of the spool valve 38b 9. It is rotatably supported via a support shaft 21a having a rotational axis 2 that is perpendicular to the axis of rotation. The support pin 22a of the swing arm l~22 has both axes 9. ! , 9. Rotation axis 9 located at the intersection of z
, 2 by rotating the supporting shaft 21a in the direction perpendicular to (j T: IQ f), the inclination angle formed by t, that is, the oscillation+JJ locus plane of the oscillation 4J arm 22 centered on the support pin 22a is perpendicular to the movement axis 9J1 (
The angle of inclination is changed with respect to the reference plane (hereinafter referred to as a reference plane).

Further, one end of a connecting rod 23 is connected to the tip of the swing arm 22 via a pole joint l-23a, and the other end of the connecting rod 23 is connected to a spool valve/38b via a ball joint 23b.
The spool valve 38b is connected to the other end portion 43, and is configured to displace the spool valve 38b in the left-right direction in response to the displacement of the tip end of the swing arm 22 in the left-right direction in FIG. 3 as the swing arm 22 swings. There is.

The connecting rod 23 has its ball joint 2
3a, and is movably supported by the rotation imparting arm 24 via a ball joint 23G.

This rotation imparting arm 24 is supported on the moving axis kneading l @2
It consists of a large-diameter bevel gear rotatably supported via gear 4a, and the heavy vehicle! A bevel gear 5d attached to the rear end of the rotation transmission shaft 5b is meshed with J'3, and the rotation of the steering wheel 3 is transmitted to the rotation imparting arm 24. Therefore, the rotation giving arm 24 and the connecting rod 23 move according to the rotation angle of the spooling wheel 3 on the moving axis II9. When the swing arm 22 swings around the support pin 22a, the axis of the pin 22a aligns with the axis of movement 9 of the spool valve 38b. s, the ball joint 23a at the tip of the swinging arm 22
The spool valve 38 only swings on the above reference plane.
b is held stationary, but the axis of the pin 22a is aligned with the movement axis 9.
．． If the swing locus plane of the swing arm 22 deviates from the reference plane by tilting with respect to
is displaced in the left-right direction in FIG. 3, and this displacement is transmitted to the spool valve 38b via the connecting rod 24, and the spool valve 38b moves along the movement axis l. That is, even if the swing angle of the swing arm 22 about the axis of the support bin 22a is the same, the displacement of the spool valve 38b in the left-right direction is due to the change in the tilt angle of the bin 22a, that is, the rotation angle of the holder 21. It changes accordingly.

In order to change the rotation angle of this holder 21,
A sector gear 25a as a 1 quarm wheel is attached to the support shaft 21a of the holder 21, and this sector gear p
A worm gear 25b is meshed with the worm gear 25a. A bevel gear 25C is mounted on the shaft of this worm gear 25b.
[This bevel gear 25c is engaged with a bevel gear 25d which is mounted on the output shaft of a stepping motor 26 as an actuator, and operates the stepping motor 26 to rotate the sector gear 25a. By changing the inclination angle of the holder 21 with respect to the reference plane, the steering angle of the rear wheels 2a, 2b, that is, the front and rear wheels 1a, lb, 2
The steering ratio and steering phase of a and 2b are controlled. moreover,
On the support shaft 21a of the holder 21, there is a steering ratio sensor 27 formed of a bodensimeter as a steering ratio detection means for detecting the rotation angle of the sector gear 25a corresponding to the actual steering ratio controlled by the stepping motor 26. It is provided.

Control of the steering ratio and steering phase by the stepping motor 26 is performed by a controller 33 that receives a vehicle speed signal from a vehicle speed sensor 34 and receives power from a battery 31. For example, as shown in FIG. 4, when the vehicle speed is zero, When the phase is opposite, the steering ratio is maximum and the vehicle speed is 301 m/i.
-1, the two-wheel steering state is at zero phase, and the vehicle speed is 12
This is done so that the steering ratio is maximized at the same phase when 0KIII/H.

Next, an apparatus for testing the four-wheel steering characteristics of a vehicle having a four-wheel steering system as described above will be shown, and its structure and characteristics testing method will be described.

FIG. 5 is a plan view showing an inspection device 40 for toe-in adjustment J3 and four-wheel steering characteristic inspection.
includes a front wheel static tester 41 that measures the toe-in angle, steering angle, etc. of the front wheels, a front wheel guide 43 that guides the left and right front wheels to the front wheel static tester 41, and a front wheel guide 43 that measures the toe-in angle, steering angle, etc. of the rear wheels. As shown in the figure, a rear wheel static tester 45 and a rear wheel guide 47 that guide the left and right rear wheels to the rear wheel static tester 45 are arranged in a line as shown in the figure. 41. The front and rear wheels are transported and guided by front and rear wheel guides 43 and 47, respectively, to perform a front and rear wheel static tester.
45. Note that this device 40 includes a signal sending means 105 that sends a medium speed signal etc. to the vehicle to be inspected, and a comparative inspection means 100 that compares the four-wheel steering characteristics measured by the device 40 with preset basic characteristics. have.

For this reason, lines 100a to 100d into which the measured values of the steering angles of the front and rear wheels are input are connected to the comparison inspection means 100.
A line 105a having a connector 105b connected to a vehicle controller is connected to the signal sending means 105.

FIG. 6 is a front view showing the front wheel static tester 41 in detail along the arrow Vl-Vl, and FIG. 7 is a detailed plan view of the static tester 41.

As can be seen from the figure, this static tester 41 consists of a pair of testers that are line-symmetrical on the left and right in order to measure the toe-in angle and steering angle of the left and right front wheels. Akebono parts will be given the same number and only one will be explained. The static tester 41 includes a full-float turntable 50 that is mounted on a support stand 41a and supports the front wheels so that they can be steered and moved left and right and back and forth, and the front wheels that are placed on the turntable 50. a front wheel angle measuring means 60 that measures the toe-in angle, steering angle, etc. of the front wheels by coming into contact with the side surface of the tire; and a tester that is mounted on the support base 41a and moves the front wheel angle measuring means 60 in the vehicle width direction. It is composed of a moving means 70. The front wheel angle measuring means 60 has a measuring plate 81 that comes into contact with the side surface of the front wheel tire, and is moved by the tester moving means 70 to bring the measuring plate 61 into contact with the side surface of the front wheel tire placed on the turntable 50. It also includes a touch sensor that measures the inclination of this measuring plate 61 to measure the toe-in angle and steering angle.

The turntable 50 will now be shown in detail in FIGS. 8 and 9, and the structure of the turntable 50 will be explained. 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 in p1 and movable to the left and right of the surface. Since this table 53 supports the front wheel by placing it thereon, front and rear guides 53a, 53a are provided for positioning the front wheel in the surface direction, and the width of the front wheel (left and right) is Left and right guide plates 53b are provided for positioning in the ) direction. Roughly speaking, a rotating shaft 54 extending downward from the center is attached to the table 53, and an encoder 55 for detecting the rotation angle of the table 53 is attached to the lower end of this rotating shaft 55.
is installed. The table 5 is in the frame 51 above.
Transport plates 51b, 51b for smoothly transporting the front wheels to the front wheels 3 are attached with the table 53 sandwiched between the front and rear sides. Further, shaft holding plates 56.56 are disposed on the frame 51, facing each other so as to sandwich the rotational shaft 54 in the front and rear directions, and movably.
56 has a central portion 511a connected to the upper end of an arm 58 rotatably attached to the frame 51.

A lower portion E 58c of the arm 58 is connected to both layers 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. Both wheel retaining plates 56.5 when
6 approaches each other, and when they shrink, they move away from each other. These two shaft holding plates 56, 56 and rotation @54 are indicated by arrows ■-■
FIG. 8A is a cross-sectional view taken along A portion 54a of the shaft 54 facing the notch S6a has a square cross section matching the notch.

Therefore, the cylinder 59 is extended and the double shaft holding plate 5
6.56, the notches 56a, 56a grip the square portion 54a and hold the rotating 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 angle measuring means 60 and the tester moving means 10 will be explained using FIGS. 10 to 12. A front wheel angle measuring means 60 consisting of a touch sensor extends forward to a frame 65 and has a support shaft 62 attached thereto, and a measuring plate 61 rotatably attached to the front end of the support shaft 62 via a ball joint 62a. ing. In this state, the measuring plate 61 is attached to the ball joint l.
Although it is rotatable about -628, it is held vertically upright with respect to the frame 65 by the compression spring 63a1, the tension spring 63b, and the link f33c. Note that the measurement plate 61 is held in an upright state when no external force acts on it, and when the measurement plate 61 receives an external force, the springs 83a and 63b are bent and the link 63G is bent. Due to the deformation, the 31II constant plate 61 moves into the ball joint 6 according to the external force.
It is rotated around 2a. Therefore, when the measuring plate 61 is brought into contact with the tire side surface of the front wheel, this measuring plate 61
Since the inclination Ij is determined according to the inclination of the measuring plate 7, by measuring the inclination of this measuring plate, it is possible to measure the toe-in angle, steering angle, camber angle, etc. of the front wheels. In order to measure the inclination angle of the measuring plate 61, three displacement measuring devices 64 are attached to the frame 65. This displacement measuring device 64 has a probe 64a that projects forward and is movable back and forth, and is attached to the left, right, and above the ball joint 62a, as shown in FIG. 12. This probe 64
When the measuring plate 61 is in contact with the side surface of the tire, the probes a come into contact with a contact pressure 61a fixed to the measuring plate 61, and when the measuring plate 61 is inclined, each probe 64a Since there is a difference in the amount of movement in the longitudinal direction (back and forth movement ω within the displacement measuring device 64), the toe-in angle,
It is possible to detect steering angle, camber angle, etc.

Specifically, the toe-in angle and the steering angle can be measured from the difference in the amount of movement after lyI of the probes 64a of the displacement measuring devices 64 arranged on the left and right sides of the ball joint 62a,
The camber angle can be measured from the average value of both movements ω and the amount of movement of the displacement measuring device 64 disposed above the ball joint 62a. Therefore, if the toe-in angle is adjusted and the steering angle is measured as in the present invention, the 2111i placed on the left and right of the ball joint 62a
Only the displacement measuring device 64 of I may be used. In addition, these displacement measuring devices 64, etc. are attached to the cover 6 as shown by the two-dot chain line in FIG.
Covered by 0a.

The front wheel angle measuring means 60 having the above structure is supported by the tester moving means 70 through the frame 65 so as to be freely movable in the front and rear direction.
Xi and this]''i1 wheel angle surface angle measuring means 60
Explain about holding. The tester moving means 10 is a support stand 41
It has a frame 71 fixed on top a, and this frame 7
1, a pair of left and right guide rods 72.
72J3 and a transport rod 74 extending back and forth between the guide iron doors 2 and 72 is supported.

Two guide legs 67° 6 are fixed to the lower surface of the frame 65 of the front wheel angle measuring means 60 on each guide 72.
7 are slidably fitted into each other, whereby the front wheel angle measuring means 60 is supported by the tester moving means 10 so as to be movable back and forth. Furthermore, a thread is formed on the outer periphery of the transport rod 74, and a front wheel angle measuring means 60 is provided.
A threaded bush 66a of a transport leg 6G fixed to the lower surface of the frame 65 is threadedly engaged with the transport rod 14. The transport rod 74 is rotatably supported by the frame 71, and a first sprocket 75a attached to the end thereof meshes with a second sprocket 750 attached to the shaft of the motor 76 via a chain 75b. By rotationally driving the motor 76 to rotate the transport rod 74, the entire front wheel angle measuring means 60 can be moved backward via the transport legs 66. In order to set the forward and backward movement positions at this time, the frame 71 of the tester moving means 70 has two limit switches 73 separated in the forward and backward directions.
．． 73 is removed, and a pair of switch plates 68 and 68 facing the limit switch 73 are attached to the frame 65 of the front wheel angle detection means 60. The drive of the motor 76 is controlled by the operation of the limit switch 13, and the forward and backward movement and positioning of the front wheel angle measuring means 60 is performed.

Although the front wheel static tester 41 has been described above, the rear wheel static tester 45 will now be described. Similar to the front wheel static tester 41, the rear wheel static tester 45 also consists of a pair of left and right testers, and each tester includes a full float type turntable 150, a rear wheel angle measuring means 160 consisting of a touch sensor, and an ask moving means. 170. As shown in FIG. 13, the turntable 150 includes a frame 151, a plurality of bearings (not shown) attached to the frame 151, and is supported by the bearings so as to be rotatable and movable back and forth and left and right. The table 153 shown on the right is slightly different in shape from the turntable 50 for the front wheels, but their function and essential structure are the same, so their explanation will be omitted.On the other hand, from the table 153 The downward extension @154 has a smaller downward extension ω than the rotation axis 54 of the front wheel table 53, and the encoder that detects the rotation of this axis only has a square cross section 154a at its lower end. Installation [Not shown. This is because in a four-wheel steering type, the turning angle of the front wheels is large, so the front wheel angle measuring means 60 alone cannot measure the turning angle.
The steering angle of the rear wheels is measured with high precision by the front wheel angle measuring means 60, and the angles exceeding the above range are measured by the encoder 55. Since it is within the range of ±5'' centering on the straight-ahead direction, the rear wheel angle measuring means 1
This is because sufficient measurement can be made with only 60. In addition, a pair of shaft holding plates 156, 156 are arranged so as to sandwich the square cross section 1S4a at the lower end of the rotation @ 154 in the front and back, and both shaft holding plates 156, 156 are normally pushed apart by the spring 151. However, the rotating shaft 154 is fixedly held by the square cross-section portion 154a being pushed by the cylinders 158, 158 arranged in the front and rear, and being held by the double-shaft holding plates 156, 156. . Rear wheel angle measuring means 160 for measuring the toe-in angle, steering angle, etc. of the rear wheels, and this rear wheel angle measuring means 1
The tester moving means 170 for moving the tester 60 in the vehicle width direction (left and right direction) has the same function and essential H4 construction as the front wheel static tester 41, so a description thereof will be omitted.

Next, the front wheel guide 43 and rear wheel guide 41 that guide the front wheels and the rear wheels to the front wheel static tester 41 and the rear wheel static tester 45, respectively, will be explained. Since both guides 43 and 47 have the same shape, the front wheel guide 43 is shown in FIG. 14 and will be described based on this. This front wheel guide 43 connects the left and right front wheels to static testers 41, respectively.
It has a pair of guide bodies 90.90 having guide grooves 90a for guiding the vehicle towards the vehicle, and these guide bodies 90.90 are movable in the vehicle width direction (left and right direction). Further, in order to correctly guide the front wheel to the guide groove 90a, a guide plate 91.91 is installed which is shaped like a "C" shape toward the driver. A rotatable first arm 92a J3 and a second arm 92b extending to the right in the figure are attached to the frame 96-97, and both arms 92a and 92b are attached to the first connecting rod 9.
Connected by 3. Further, as shown in the figure, the first arm 92a is connected to a guide body 90 that supports the right front wheel by a second connecting U-piece 95, and a guide body 9o that supports the left front wheel.
On the frame 97 facing outside the frame 97, there is a third nonome 92c extending forward (to the left in the figure) from the handle part of the second arm 92b and rotates integrally with the second arm 92b. This third arm 92c is freely attached, and as shown in the figure, this third arm 92c is connected to a guide body 90 that supports the left m-wheel by a third connecting rod 94. 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. Therefore, even if the front wheel tread is at fault, the distance between the guide bodies 90, 90 can be adjusted in accordance with this tread.

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 a head 101a having a groove 101b is attached to its upper end.

Therefore, when the rod 101 of the cylinder 102 is extended upward, the l 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 placed on full-float turntables, when an external force is applied to the vehicle body in the horizontal direction, the turntables are rotated and the vehicle body is rotated, allowing measurements by the front and rear wheel angle measuring means to be carried out. Although this may be inaccurate, by supporting the vehicle body by lifting it up with the lifter, it is possible to prevent the heavy body from being moved even if a horizontal external force is applied to the vehicle body. Furthermore, by lifting the vehicle body with the lifter, the weight of the vehicle body applied to the tie puller 7 placed on the return table can be reduced.

This reduces the deformation of the tire, and when measuring the turning angle with the Tadge type sensor, this hin is the shadow of the deformation of the tire! This reduces the error in the measured values, and furthermore, the load on the turntable is reduced, allowing the turntable to rotate smoothly.

A second method for testing the four-wheel steering characteristics of a vehicle equipped with a four-wheel steering device using the testing device 40 as described above.
The explanation will be given by taking the four-wheel steering vehicle shown in the figure as an example. first,
Front wheel turntable 50 and rear wheel turntable 15
0 cylinders 59, 158, 158 are extended and the rotating shaft 54 is held by the shaft holding plates 56, 56 and 156, 156.
, 154, the vehicle is conveyed onto this device 40 in the direction of the arrow from the right side of the figure in FIG.
Front wheels 1a, 1 by front wheel and rear wheel guides 43.47
Place the wheels 2a and 2b on the front and rear static testers 41 and 45, respectively.Next, move the heads 101a of the lifters 48 and 49 to the side sills of the vehicle body using the head 101a of the upper shaft wrench. Hold it,
The load on the turntables 50, 150 from the front and rear wheels is reduced, and the vehicle body is held to prevent horizontal movement of the vehicle body due to external force.

The lifting force of the vehicle body by the lifters 48, 49 is set so that a large amount of load is left on the tables 53, 153 so that the tables 53, 153 are rotated smoothly in accordance with the turning of the front wheels and rear wheels. Next, the front wheel turntable 5
0 and each cylinder 59 of the rear wheel turntable 150
, 158, 158 are contracted to release the fixed holding of the rotating shafts 54, 154 by the shaft holding plates 56, 56 and 156, 156, and the tables 53, 153 are brought into a fully floating state.

From this state, toe-in adjustment of the front wheels and rear wheels is first performed. This toe-in adjustment is performed with the front wheel J3 and the rear wheel steering means 4.10 disconnected by the connecting means 6.
The front and rear wheels are performed separately. In this case, the 1-1 inch angle is measured by the angle measurement means 60, 160 consisting of the touch type sensors of the front and rear wheel static testers 41, 45, and the front and rear wheels are facing straight and the steering wheel is horizontal. The toe-in angle in the facing state is adjusted to a predetermined value, and then the front wheels and the rear wheel steering means are connected by the connecting means 6, but a detailed explanation of the adjustment method is as follows. Omitted.

a3. 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 described above, the four-wheel steering characteristics are inspected. Adjustment of the four-wheel steering characteristics is performed by adjusting the steering angles of the front wheels 1a, ib and the rear wheels 2a,
2b to measure and inspect the relationship with the steering angle,
The specific inspection method will be explained below.

First, a simulated vehicle speed signal (for example, vehicle speed 1201
A vehicle speed signal corresponding to fIn/l-1) is sent out. In this state, operate the steering wheel 3 to rotate the front wheels 1a and 1.
When wheel b is steered, the rear wheels 2a and 2b are also steered in the same phase, so the steered angles of these front and rear wheels are measured by the front and rear wheel static desks 41.45. The graph in FIG. 16 shows an example of the relationship between the front wheel turning angle and the rear wheel turning angle measured in this manner. 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. There is. As you can see from this graph, when the front wheels are steered to the right, the rear wheels are also steered to the right (steered in the same phase), and this change in the steering angle of the rear wheels gradually decreases, and steering is not performed at a predetermined steering angle (maximum right steering angle) of 61 or more. The same is true when the front wheels are steered to the left, and the rear wheels are steered while gradually reducing the change until the left side maximum steering angle θ2 is in the same phase.

Next, a simulated vehicle speed signal (for example, a medium speed signal corresponding to a vehicle speed of 30 KIR/H) is sent from the signal sending means 105 to the controller 33 via the line 105a so that the steering phase becomes zero phase. In this state, steering wheel 3
to steer the front wheels 1a, 1b, b, rear wheels 2a,
2b should be held at zero phase and not steered.

The steering angles of these front and rear wheels are static.
The graph in FIG. 17 shows an example of the relationship between the front wheel steering angle and the rear wheel steering angle measured by the desks 41 and 45 in this manner. As you can see from this graph, when the front wheels are steered to the right, the rear wheels are hardly steered and the brush cutter rl? A very small steering angle θ1 due to the difference etc. θ
Only 2 occurs.

Furthermore, a simulated vehicle speed signal (for example, vehicle speed
Outputs (corresponding vehicle speed signal)).

In this state, move the front wheel 1 by operating the 7 ring wheel 3.
When wheels a and Ib are steered, the rear wheels 2a and 2b are steered in opposite phases, so the steered angles of these front and rear wheels are measured by front and rear wheel static testers 41 and 45. The graph in FIG. 18 shows an example of the relationship between the front wheel turning angle and the rear wheel turning angle measured in this manner. As you can see from this graph, when the front wheels are steered to the right, the rear wheels are accordingly steered to the left (steered in the opposite phase), and this change in the steering angle of the rear wheels gradually decreases and will not be steered at a predetermined steering angle (maximum steering angle on the left side) of 01 or more.The same is true when the front wheels are steered to the left, and the rear wheels are in the opposite phase until the maximum steering angle on the right side is θ2. The ship is steered while gradually reducing the change.

In addition, in the measurement of the steering angle of the front wheels and rear wheels using the static testers 41 and 45, the steering angle of the front wheels is determined by the touch sensor in the range where the steering angle is small (within a range of ±5°). The angles exceeding this range are measured by the encoder (rotation angle detector) 55 attached to the lower end of the rotating shaft 54 of the turntable 50, and -
The force and the rear wheel turning angle are measured by a rear wheel angle measuring means 160 consisting of a touch type sensor.

Desired basic characteristics are set in advance for each of the characteristics of the rear wheel steering angle change corresponding to the front wheel steering angle when various vehicle speed signals are input, which are measured as described above.
The comparative inspection means 100 compares the basic characteristics with the above-mentioned measured characteristics to determine whether the measured characteristics are within the required range of the basic characteristics M, and the maximum steering angles θ1 and θ2 are set in advance. It is checked whether the steering characteristics are within a predetermined range as a basic characteristic, and if the steering characteristics are not within a predetermined range, the steering characteristics are adjusted to meet the basic characteristics.

Next, an example of the test method according to the present invention will be explained.

For this inspection, the steering wheel 3 is reciprocated left and right around its horizontal direction, and the front wheels 1a, lb.
The vehicle is steered reciprocally within a predetermined range around its straight forward direction. In this case, the front wheel turning angle range may be a small range, for example, in this example, about ±3°. At this time, highly accurate steering angle measurement is performed by the front wheel angle measuring means 60 consisting of a touch type sensor. By steering this front wheel, the rear wheel 2
Since a and 2b are also steered, the characteristics are tested by measuring the steering angles of the front and rear wheels at this time. , it is preferable to input a vehicle speed signal that maximizes the steering ratio to the controller 33. Therefore, the connector 10 of the signal exit means 105
5b is connected to the controller 33 instead of the vehicle speed sensor of the vehicle to be inspected, and a vehicle speed signal (vehicle speed OKIR/H or 1201 to /H) that maximizes the steering ratio is sent from the signal sending means 105 via the line 105a. A corresponding vehicle speed signal) is sent to the controller 33.

- Angle measuring means 60 consisting of touch sensors of front and rear wheel static testers 41 and 45 measures the turning angle of the front wheels and rear wheels when the front wheels are turned by operating the steering wheel under the above conditions. , 160. An example of this measurement result is expressed by showing the rear wheel steering angle on the vertical axis and the front wheel steering angle on the horizontal axis. As shown by the solid line in the graph of Fig. 16, the trajectory has a certain hysteresis. is 1;7. The reason why the trajectory of hysteresis is 17 is because there is backlash in the connection system between the front wheel steering means and the rear wheel steering means. In this case, if the rear wheel steering angle is adjusted when the front wheel steering angle is zero, it is not possible to adjust the rear wheel steering angle based on either the rightward or leftward steering of the front wheels. Since the steering angle of the 112 wheels will deviate and the running stability will be impaired, in the present invention, in the comparative inspection means 100 that receives the measurement signal, the curve β representing the middle point of the circular locus is set to the origin on the graph. I am trying to check whether it passes or not. However, when turning to the right, the trajectory curve becomes t<+, and when turning to the left, the trajectory curve becomes 1.
! It is checked whether or not the trajectory curve represented by 'I' is approximately point-to-customer centered around the origin. Then, the rear wheel steering means is adjusted so that the curve β passes through the origin.

' In the J3 vehicle using the four-wheel steering means shown in FIGS. 2 and 3, the neutral return springs 14a and 14b are precompressed, so the rear wheels 2a and 2b are moved to the straight-ahead position ( When steering from the position where the steering angle is zero) to either the left or right, the dead zone where the rear wheels are not steered relative to the steering of the front wheels (the position where the front wheel steering angle is zero) A portion where the trajectory curve is almost horizontal occurs in the vicinity of . So, for example, the front wheel steering angle α when this dead zone occurs! .

Read α2, both steering angles α1. It may be checked whether the median value of α2 is zero, that is, whether both dead zones are point symmetrical with respect to the origin.

In this example, a method for testing four-wheel steering characteristics was explained using an example of a vehicle having an electro-hydraulic four-wheel steering mechanism that controls the steering ratio and steering phase according to the vehicle speed. The present invention is not limited to this, but is applicable to a vehicle having a mechanical mechanism that mechanically transmits the steering of the front wheels to the rear wheels and controls the steering of the rear wheels in accordance with the steering of the front wheels. The same is true.

In addition, the inspection device and method according to the present invention are not limited to the inspection shown in this example, but can also be used for various types of four-wheel inspection, such as inspection of the operation of a fail-safe mechanism, inspection of changes in rear wheel steering angle in response to changes in vehicle speed, etc. Used to test steering characteristics.

(Effects of the Invention) As explained above, according to the present invention, there is provided a front wheel turntable in which the left and right front wheels are each supported in a steerable manner, and a rear wheel turntable in which the left and right rear wheels are each supported in a steerable manner. A table, a front wheel steering angle measuring means for measuring the steering angle of the Iyr wheels, a rear wheel steering angle measuring means for measuring the steering angle of the rear wheels, and a front wheel turning angle and a rear wheel turning angle are arranged on the left and right sides of the vehicle. A lifter that lifts the vehicle body with the front and rear wheels respectively mounted is placed on the right, and by lifting the vehicle body with this lifter, the grounding force of the tie 7 of the front wheel is reduced. When turning the front and rear wheels to test the four-wheel steering characteristics of a vehicle, the ground contact force of the front and rear wheels to the turntable, that is, the weight of the vehicle applied from the front and rear wheels to the turntable, is reduced.
There is less deformation of the tie 87 of the front and rear wheels, and the deformation of the tires during steering is also reduced. Therefore, when measuring the steering angle using the touch sensor, this sensor is less affected by the deformation of the tire, and the error in the measured value is also reduced. Furthermore, since the load on the turntable is small, the force required to rotate the turntable is reduced, allowing smooth steering.

[Brief explanation of the drawing]

Fig. 1 is a plan view schematically showing a four-wheel steering system for a vehicle, Fig. 2 is a schematic plan view of the four-wheel steering system, Fig. 3 is a schematic perspective view showing a variable steering ratio mechanism, and Fig. 4 is a schematic plan view of the four-wheel steering system. is a graph showing the relationship between vehicle speed and steering angle, Fig. 5 is a plan view showing the inspection device, Fig. 6 J3 and Fig. 7 are a front view and plan view of the front wheel static tester, Figs. 8 and 9 Figure 8A shows the front sectional view J3 and side view showing the turntable for the front wheels, and Figure 8A shows the turntable along the arrows ■-■? 10 to 12 are front views, top views, and side views showing the front wheel angle measurement f=stage J3 and σ tester moving means. FIG. 13 is a front view showing the turntable for the rear wheels. Figure 14 is a polygon plan view of the front wheel guide, Figure 15 is a sectional view showing the beam cover, and Figures 16 to 19 are graphs showing examples of measurement results of changes in rear wheel steering angle relative to front wheel steering. It is. 4... Front wheel steering means 6... Connection means 10...
- Rear wheel steering means 14a, 14b... Neutral return spring 20... Steering ratio variable n structure 26... Stepping motor 27... Steering ratio sensor 33... Controller 34... Vehicle speed sensor 38 ...:1
control valve 40...inspection device 41.45.
... Static tester 43, 47-8. guide
48, 49... Lifter 50, 150... Turntable 60, 160... Angle measuring means 70.1
7 (1... Tester transfer means Fig. 1 2υ Fig. 4 Fig. 9<D Ov Fig. 12 Fig. 14 Fig. 92C': JZD Fig. 16? begging in the house

Claims (1)

[Claims] 1) 4 in which the rear wheels are steered in accordance with the steering of the front wheels.
A device for inspecting the four-wheel steering characteristics of a vehicle having a wheel steering device, the device comprising: a front wheel turntable on which left and right front wheels are each supported in a steerable manner; and a rear wheel on which left and right rear wheels are each supported in a steerable manner. a front wheel steering angle measuring means for measuring the steering angle of the front wheels; a rear wheel steering angle measuring means for measuring the steering angle of the rear wheels; and the turntable for the front wheels and the turntable for the rear wheels. It consists of a lifter that lifts up the vehicle body with the left and right front and rear wheels of the vehicle mounted respectively,
A four-wheel steering characteristic testing device for a vehicle, characterized in that the ground contact force of the front and rear tires is reduced by lifting the vehicle body using the lifter.