JPH1059202A - Steering device of wheel vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce variation of the position of the center of gravity of a vehicle at steering by comparing the bending limit angle of the vehicle with the bending angle, and providing a pressure setting means outputting a pressure setting signal to brake oil pressure control valves based on the compared result. SOLUTION: A vehicle body bending limit angle computed by a bending angle computing means 17 is compared with a bending angle detected by a vehicle body bending angle detecting means 10 by a bending angle comparing means 18. Based on the compared result by the bending angle comparing means 18, and based on the steered direction detected by the vehicle bending angle detecting means 10, a pressure setting signal is output from a pressure setting means 19 to the brake oil pressure control valves 64a, 68a of the inside wheel axles of steered turning. Hereby, bending of the vehicle body is reduced, and variation of the position of the center of gravity of the vehicle is reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wheeled vehicle in which a front vehicle body having front wheels and a rear vehicle body having rear wheels are steered by refracting about a vertical axis at an intermediate position in the longitudinal direction of the vehicle. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a steering device, and more particularly, to a steering device that improves the stability of a vehicle in a turning steering.

[0002]

2. Description of the Related Art Conventionally, a wheel vehicle that steers by bending a vehicle body includes a front vehicle body having left and right front wheels, a wheel shaft transmitting power to the left and right front wheels, and a brake for braking the wheel shaft. Left and right rear wheels, a wheel axle that transmits power to the left and right rear wheels, and a rear body with a brake that brakes the wheel axle,
A connecting means for connecting the front body and the rear body flexibly; and a telescopic actuator having one end attached to the front body and the other end attached to the rear body. The vehicle is steered by bending the vehicle body.

[0003]

A steering apparatus for a wheeled vehicle that bends and steers a vehicle body can perform steering of the vehicle with a relatively small turning radius, such as a wheel loader of a construction machine. It is used in vehicles that require many steering operations and a small steering turning radius in order to repeatedly perform cycles such as excavation, transportation, and loading. However, in order to perform steering by bending the vehicle body, in FIG. 5 showing steering to the left as an example, steering performed by bending the vehicle body has a shape of the vehicle body as shown in FIG. Change, Figure 5
The center of gravity CG of the vehicle fluctuates by the dimension S from the center of the vehicle as compared with the steering of the wheel steering system in which the shape of the vehicle body does not change as shown in FIG. Since the direction and magnitude of the running acceleration also change due to the change in the position of the center of gravity CG, there is a limitation in steering at high speed by bending the vehicle body from the viewpoint of vehicle stability. Vehicles are mainly used for work vehicles mainly driven at relatively low speeds. However,
One of the operations of the wheel loader, excavates earth and sand with a bucket attached to the vehicle body, and transports a relatively long distance to the accumulation location of earth and sand with the earth and sand loaded on the bucket,
2. Description of the Related Art In a work such as a so-called load and carry (loading and carrying), traveling at a high speed is required to improve work efficiency.

[0004] Depending on the type of work vehicle that travels while bending and steering the vehicle body, one of the left and right wheels of either the front vehicle body or the rear vehicle body is mounted on an integrated common axle housing via a buffer suspension. The right and left wheels are fixed directly to the vehicle body, and the other left and right wheels are mounted on a common axle housing, which is also integrated. Is mounted so as to be swingable like a seesaw around a swing shaft provided extending in the front-rear direction. Even in this case, no shock suspension is provided between the vehicle body and the axle housing. By making the left and right front wheels or the left and right rear wheels swingable with respect to the vehicle body, all of the left and right front wheels and the left and right rear wheels are always in contact with the ground even on uneven terrain, and the wheel vehicle The wheel driving force (traction force) is effectively exerted. However, since the left and right wheels of either the front vehicle body or the rear vehicle body are swingable with respect to the vehicle body, the centrifugal force of the steering turning increases during steering at high speed, and the However, the position of the center of gravity of the vehicle fluctuates due to the inclination of the vehicle body, and the fluctuation of the center of gravity due to the refraction of the vehicle body, as well as the stability of the vehicle, restricts the high-speed steering.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned circumstances, and a technical problem thereof is to provide a steering apparatus for steering a wheel vehicle that bends a vehicle body to reduce fluctuations in the center of gravity of the vehicle during steering. It is to provide.

[0006]

According to the present invention, in order to solve the above-mentioned technical problems, the refraction of the vehicle body during steering can be reduced, and the swing of the wheels with respect to the vehicle body during steering can be reduced. Be regulated. (1) As means for reducing the refraction of the vehicle body during steering,
From the relationship between the traveling speed of the vehicle during steering and the position of the center of gravity of the vehicle, a vehicle body refraction limit angle that can be steered stably with respect to the traveling speed is obtained. Brake the front and rear wheels so that the difference between the rotational speeds of the inner and outer wheels of the vehicle is larger than the difference between the rotational speeds of the inner and outer wheels determined through a normal differential. In addition, the steering is performed by braking the wheels in addition to the steering due to the bending of the vehicle body. by this,
Since the refraction of the vehicle body can be reduced, the same turning radius as that obtained when the vehicle body is largely refracted can be obtained with less fluctuation of the center of gravity of the vehicle than before. (2) To reduce the swing of the wheels with respect to the vehicle body during steering,
Alternatively, as the elimination means, a swing regulation means for regulating the swing is provided between the vehicle body and the axle housing to which the wheels are attached. The swing regulation means is configured to fix the relative relationship between the vehicle body and the axle housing, or to regulate the amount of movement, or to regulate the speed of movement. by this,
Since the swing of the wheel with respect to the vehicle body is restricted, the fluctuation of the position of the center of gravity of the vehicle due to the swing can be reduced.

That is, according to the present invention, a steering apparatus for a wheeled vehicle that solves the above technical problem has a traveling speed detecting means for detecting a traveling speed of a wheeled vehicle, and a refraction angle between a front vehicle body and a rear vehicle body. Body refraction angle detecting means for detecting,
A brake oil pressure control valve for controlling the oil pressure of the wheel axle brake; and a control means, wherein the control means calculates a vehicle body refraction limit angle of the vehicle based on a signal from the traveling speed detection means; Refraction angle comparison means for comparing the vehicle body refraction limit angle calculated by the angle calculation means with the refraction angle detected by the vehicle body refraction angle detection means, and pressure setting for the brake hydraulic control valve based on the comparison result by the refraction angle comparison means Pressure setting means for outputting a signal.

[0008] In a preferred embodiment, the steering device for a wheeled vehicle further includes a wheel shaft rotational speed detecting means for detecting a rotational speed of a wheel shaft, and a steering detecting means for detecting an operating state of a steering wheel. The control device further includes a steering turning radius of the vehicle as a set speed ratio which is set based on a signal from the steering detection means, based on a ratio between a turning outer wheel shaft rotation speed of the vehicle and a turning inner wheel shaft rotation speed of the vehicle. Turning radius commanding means for instructing, speed ratio calculating means for calculating the ratio between the turning outer wheel shaft rotational speed and the turning inner wheel shaft rotational speed based on a signal from the wheel shaft rotational speed detecting means, and speed ratio calculating means. A speed ratio comparing means for comparing the calculated speed ratio with the set speed ratio, and a pressure setting signal output from the pressure setting means to the brake hydraulic control valve based on a comparison result by the speed ratio comparing means. And a correction pressure setting signal correcting means.

[0009] In another embodiment, the steering device comprises:
A swing regulating means for regulating the swing of a front wheel or a rear wheel which is swingably attached to the front vehicle body or the rear vehicle body is provided.

[0010] The steering apparatus for a wheeled vehicle according to the present invention includes:
It is controlled as follows. (1) The running speed detecting means measures the rotation speed of the propulsion shaft that drives the wheel shaft, and detects the running speed of the vehicle. (2) Based on the detected traveling speed, the vehicle body refraction limit angle at the detected traveling speed of the vehicle is computed by the refraction angle computing means. (3) The vehicle body refraction angle detecting means detects a refraction angle and a refraction direction to the left and right due to steering from a straight state between the front vehicle body and the rear vehicle body. (4) The calculated refraction angle of the vehicle body is compared with the detected refraction angle by the refraction angle comparison means. (5) The pressure setting means outputs a pressure setting signal to the brake hydraulic control valve based on the comparison result. (6) The set brake oil pressure is applied to the brake of the steered turning inner wheel shaft by the brake oil pressure control valve.

In the preferred embodiment, (7) the rotation speed of each of the front, rear, left and right wheel shafts is detected by the wheel shaft rotation speed detecting means. (8) The state of the steering operation by the steering wheel is detected by the steering detection means. (9) Based on the signal from the steering detecting means, the turning radius command means instructs the steering turning radius of the vehicle according to the set speed ratio set by the speed ratio by the following formula. (10) The speed ratio calculating means calculates the ratio between the turning outer wheel shaft rotational speed and the turning inner wheel shaft rotational speed and the speed ratio based on the signal from the wheel shaft rotational speed detecting means. (11) The speed ratio comparing means compares the speed ratio calculated by the speed ratio calculating means with the set speed ratio. (12) The pressure setting signal output from the pressure setting means to the brake hydraulic control valve is corrected by the pressure setting signal correction means based on the comparison result by the speed ratio comparing means.

(13) When the swing regulating means is provided, a signal for operating the swing means is output together with the output of the pressure setting signal.

Thus, the wheels on the inside of the steering turn are braked by the brake, and the rotational speed difference between the inner wheels and the outer wheels is further increased. Steering is also performed by braking the wheels in addition to bending the vehicle body. It is. That is, the vehicle can be steered in a state of a stable vehicle body with less change in the center of gravity of the vehicle than before, with less body refraction than in the past.

Further, since the rocking of the wheels with respect to the vehicle body is controlled by the rocking control means, the rocking of the vehicle is suppressed as compared with the prior art, and the steering is performed in a stable state of the vehicle body with little change in the position of the center of gravity of the vehicle. Is performed.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of a steering apparatus for a wheeled vehicle constructed according to the present invention will be described below with reference to the accompanying drawings.

Referring first to FIG. 1, the outline of the body of a wheeled vehicle will be first described. In a wheeled vehicle according to the present invention, a front body 2 and a rear body 4 of the vehicle are vertically connected to the plane of FIG. It is connected so as to be pivotable, that is, to bend freely around a central axis. One end of the hydraulic cylinder 8 as an extendable actuator is
The other end is rotatably attached to the rear vehicle body 4 and is interposed between the front vehicle body 2 and the rear vehicle body 4. In the illustrated embodiment, the number of hydraulic cylinders 8 is one, but a plurality of hydraulic cylinders 8 may be provided on the opposite side symmetrically with respect to the connecting means 6. A driver's seat for driving a wheeled vehicle is provided on the front vehicle body 2 or the rear vehicle body 4, and a steering shaft 72a is rotated by operating a steering wheel 72 of the driver's seat. Is driven to rotate, a steering control valve (not shown) is operated by the discharged oil, the pressure oil to the hydraulic cylinder 8 is controlled, and the front vehicle body 2 and the rear vehicle body 4 are bent around the connecting means 6. Is done. When the hydraulic cylinder 8 is extended, the front vehicle body 2 is bent leftward from the straight state shown in the figure with respect to the rear vehicle body 4, and the vehicle is steered leftward. Similarly,
When the hydraulic cylinder 8 is contracted, the front vehicle body 2 is bent rightward, and the vehicle is steered rightward.

Next, a transmission system for the traveling power of a wheeled vehicle according to the present invention will be described. A front axle housing 24 is directly fixed and attached to a front body 2 of the vehicle without using a shock absorber such as a spring. . The front axle housing 24 includes a differential 42 in the center, and a left front wheel axle 30a and a right front wheel axle 30b extending left and right from the differential 42.
Are accommodated, and a left front wheel 22a and a right front wheel 22b are attached to respective ends of a left front wheel shaft 30a and a right front wheel shaft 30b protruding from the front axle housing 24.
A rear axle housing 26 is provided on the rear body 4 of the vehicle, similar to the front axle housing 24, without extending through a shock absorbing device, and the swing shaft 2 provided at the center of the left and right extending in the front-rear direction of the rear body.
The swing shaft 26a and the swing of the rear axle housing 26 are swingably attached to the rear body 4 by 6a. The rear axle housing 26 houses a differential 44 at the center, and a left rear wheel axle 46a and a right rear wheel axle 46b extending left and right from the differential 44, and a left rear wheel axle 46a protruding from the rear axle housing 26. A left rear wheel 38a and a right rear wheel 38b are attached to each end of the right rear wheel shaft 46b. On the rear body 4,
A transmission 20 for shifting the traveling power from a prime mover (not shown) is provided. The running power from the transmission 20 is connected to the differentials 42 and 44 by the propulsion shafts 28 and 50, respectively.

Each of the left front wheel axle 30a and the right front wheel axle 30b has a left front wheel axle brake 34a for braking the wheel axle.
And the right front wheel axle brake 34b is connected to the front axle housing 24.
It is housed in and provided. The left rear wheel axle 46a
A left rear wheel axle brake 60a and a right rear wheel axle brake 60b are accommodated in the rear axle housing 26 and provided on each of the right rear wheel axle 46b.

Each of the wheel axle brakes 34a, 34b, 6
Brake hydraulic pressure control valves 64a, 64b, 68a, and 68b for controlling a brake operating hydraulic pressure that determines a brake braking force are provided for each of Oa and 60b. Each of the brake hydraulic pressure control valves 64a, 64b, 68a, and 68b is configured by an electromagnetic proportional solenoid valve that outputs a brake hydraulic pressure in proportion to an electric signal.

Next, the various detecting means according to the present invention will be described. The propulsion shaft 28 which transmits the output rotation from the transmission 20 to the differential 42 provided on the front vehicle body 2 includes the traveling speed detecting means 14. Is provided, and the rotational speed of the propulsion shaft 28 is measured, whereby the running speed of the vehicle is detected.

The front, rear, left and right wheel shafts 30a, 30b, 46
a and 46b respectively include wheel axle rotation speed detecting means 52a, 52b, 5
6a and 56b are provided.

The steering shaft 72a of the steering wheel 72 is provided with a steering detecting means 74 for detecting the operation state of the steering wheel 72 based on the rotation angle and the rotation speed of the shaft 72a.

A vehicle body refraction angle detecting means 10 is provided at the turning center of the connecting means 6 for connecting the front vehicle body 2 and the rear vehicle body 4, and the front vehicle body 2 and the rear vehicle body 4 are straightened in the longitudinal direction of the vehicle. (Represented state), the refraction angle to the left or right, that is, the vehicle body refraction angle which is the relative angle between the front vehicle body 2 and the rear vehicle body 4,
It is detected by the rotation angle sensor together with the direction of refraction (left or right).

Next, the control means 16 will be described. The control means 16 which can be provided at an arbitrary position on the vehicle is provided with a refraction angle calculation for calculating a vehicle body refraction limit angle based on a signal from the traveling speed detection means 14. Means 17, a refraction angle comparison means 18 for comparing the vehicle body refraction limit angle calculated by the refraction angle calculation means 17 with the refraction angle detected by the vehicle body refraction angle detection means 10, and a refraction angle comparison means 1
8, based on the steering direction (left or right) detected by the vehicle body refraction angle detection means 10, the brake hydraulic control valves 64a and 68a (steer to the left) of the steer turning inner wheel shaft. ), Or 64b and 68
b (in the case of rightward steering) and a pressure setting means 19 for outputting a pressure setting signal.

The control means 16 further sets the vehicle speed as a set speed ratio based on a signal from the steering detection means 74 as a set speed ratio which is set by a ratio of a rotation speed of the outside wheel shaft of the vehicle to a rotation speed of the inside wheel shaft of the vehicle. Turning radius commanding means 62 for commanding a steering turning radius, and wheel shaft rotation speed detecting means 52a, 52b;
Speed ratio calculating means 66 for calculating the ratio between the turning outer wheel shaft rotation speed and the turning inner wheel shaft rotation speed based on the signals from 56a and 56b, the speed ratio calculated by the speed ratio calculating means, the set speed ratio, Speed ratio comparing means 70 for comparing
And a pressure setting signal correcting means 76 for correcting the pressure setting signal output from the pressure setting means 19 based on the comparison result by the speed ratio comparing means 70.

Next, a description will be given of the means for restricting the swing of the wheels with reference to FIG.
8a and 38b are attached to the rear body 4 so as to be swingable, and the whole number is 80 between the rear axle housing 26 and the rear body 4, or the whole number is 90 in another embodiment. Shown is provided. FIG.
(A) shows a swing regulating means 80 which is an embodiment for regulating the swing movement so as to fix or adjust the swing amount. FIG. 4B shows a swing regulating means 90 which is an embodiment for regulating the swing movement so as to be fixed or the movement speed of the swing is buffered.

First, the swing between the rear axle housing 26 to which the rear wheels 38a and 38b are attached and the rear vehicle body 4 will be described with reference to FIG. 4 (a). A certain center is located on the rear body 4, and a bracket 4 a provided at the left and right center of the rear body 4 and a swing axis 26 a whose axis extends in the front-rear direction of the rear body 4 are indicated by an arrow Y around the swing axis 26 a. The seesaw is mounted such that the seesaw movement, that is, swinging, which is a relative movement between the rear body 4 and the rear axle housing 26, can be freely performed. The magnitude of the swing is such that the stopper 4b provided on the rear body 4 and the stopper 26c provided on the rear axle housing 26 come into contact with each other within a range where the left and right rear wheels 38a and 38b do not interfere with the rear body 4. Is restricted by letting

4 (a), the rear body 4 has a channel-shaped (U-shaped) opening width W, and the opening width W is gradually expanded at the opening end. The swing receiver 82 is fixed, an L-shaped swing regulating lever 84 is provided on the rear axle housing 26, an end of one side of the L-shape is rotatable by the shaft 84 a on the axle housing 26, and the L-shape is The other end is regulated by the thickness T, and is provided so as to be able to enter and exit the opening width W of the swing receiver 82. A restricting operation hydraulic cylinder 86 is rotatably mounted at one end to the axle housing 26 by a shaft 86a and at the other end to the center of a swing restricting lever 84 by a shaft 86b. Always regulated operating hydraulic cylinder 86
Is contracted by an urging means (not shown) such as a spring or a hydraulic pressure (not shown), and the end of the thickness T of the swing regulating lever 84 enters the opening width W of the swing receiver 82. Not. In this state, the rear axle housing 26
The swing between the vehicle and the rear vehicle body 4 is not restricted. Here, when the hydraulic pressure is applied to the regulating hydraulic cylinder 86 by a hydraulic control valve (not shown) to extend the cylinder 86 against the urging means, the swing width of the swing receiving lever 82 is changed to the swing width of the swing receiver 82.
, The relative movement between the rear vehicle body 4 and the rear axle housing 26, that is, swinging is restricted. If the opening width W of the swing receiver 82 and the thickness T of the swing restricting lever 84 are made substantially the same, the swing is fixed, and the opening width W of the swing receiver 82 is fixed. And the thickness T of the swing regulating lever 84, the swing amount is regulated by the degree of the difference. That is, if the difference is large, the amount of swing is large, and if the difference is small, the amount of swing is small. The hydraulic pressure for extending the swing operation hydraulic cylinder 86 is applied to the regulating operation hydraulic cylinder 86 in accordance with the output of the pressure signal to the brake hydraulic control valve from the control means 16 when the vehicle body reaches the refraction limit angle, for example. This is done by switching a hydraulic control valve (not shown) to supply pressurized oil.

Referring to FIG. 4B, another embodiment of the swing restricting means will be described. The swing restricting means indicated by the reference numeral 90 is provided between the rear body 4 and the rear axle housing 26. The swing control hydraulic cylinder 92 and the swing operation switching valve 94 are provided. The swing regulating hydraulic cylinder 92 is rotatably attached to the rear axle housing 26 at one end by a shaft 92a and at the other end by a shaft 92b. The swing operation switching valve 90 is provided in a flow path between the swing regulating hydraulic cylinder 86 and the hydraulic tank 96,
The oil flowing into or out of the swing regulating hydraulic cylinder 92 due to the expansion and contraction of the swing regulating hydraulic cylinder 92 caused by the swing between the rear vehicle body 4 and the rear axle housing 26 is blocked (position (a)) or throttled. (Position (b)) or fully open (position (c)). When the flow path is shut off, the swing regulating hydraulic cylinder 86 cannot be expanded or contracted, and cannot swing. By narrowing the flow passage, the speed of the expansion and contraction of the swing regulating hydraulic cylinder 86 becomes slow, that is, the swing becomes slow. By fully opening the flow path, the expansion and contraction of the oscillation restricting hydraulic cylinder 86 is not restricted, that is, the oscillation is free. The drawing shows a state in which the flow path of (c) is fully opened. Swing operation switching valve 94
For example, when the body reaches the refraction limit angle and the brake pressure signal is output, the signal is received,
This is performed by switching to a preselected position (a) or (b).

Next, the operation procedure of the steering apparatus for a wheeled vehicle constructed according to the present invention will be described with reference to the flowcharts shown in FIGS. 2 and 3 together with FIG.

Referring to FIG. 2 together with FIG. 1, in the initial state of step S-1, the pressure setting signal of the pressure setting means 19 for outputting a pressure setting signal to the brake hydraulic valve is turned off. No signal is output.

In step S-2, the traveling speed detecting means 14 measures the rotation speed of the propulsion shaft 28, and detects the traveling speed V of the vehicle.

In step S-3, based on the detected traveling speed V, the vehicle body refraction limit angle θ at the detected traveling speed V by the refraction angle computing means 17 included in the control means 16 is calculated.

In step S-4, the body angle between the front body 2 and the rear body 4 is changed by the vehicle body refraction angle detecting means 10 from the straight state to the left and right refraction angle α and the refraction direction, that is, the steering direction. Is detected.

In steps S-5 and S-6, the refraction angle comparing means 18 included in the control means 16
The calculated body refraction limit angle θ and the detected refraction angle α
Is compared with

If the detected refraction angle α is smaller than the calculated vehicle body refraction limit angle θ, the process returns to step S-1. In this case, since the actually detected refraction angle α is smaller than the vehicle body refraction limit angle θ, the steering can be continued without braking the steered turning inner wheel.

On the contrary, if the detected refraction angle α is larger than the calculated vehicle body refraction limit angle θ, the process proceeds to step S.
In this case, since the refraction angle α is the vehicle body refraction limit angle θ, in order to brake the steered turning inner wheel,
By the pressure setting means 19 included in the control means 16, the corresponding brake hydraulic control valve, the left brake hydraulic control valves 64a and 68a when turning left, and the right brake hydraulic control valve when turning right. A pressure setting signal is output to 64b and 68b.

Thus, the set brake fluid pressure is applied to the left and right brakes 34a and 60a or the right brakes 34b and 60b of the steered turning inner wheel axle, and the steered turning inner left wheels 22a and 38a or the right wheel 22b and 38b
Is braked. After the pressure setting signal is output in step S-7, the process returns to step S-2.

An allowable range of the upper and lower limits is set for the vehicle body refraction limit angle θ. If the calculated vehicle body refraction angle α is within the allowable range, the process returns to step S-1.

When the above-mentioned pressure setting signal correcting means 76 and its related components are further provided in the steering device, step-7 is performed.
The output of the pressure signal in step S-8 is as follows.
It is controlled by the subsequent flow.

Step S will be described with reference to FIG. 3 in which the flow of the pressure signal correction is added to FIG. 2 together with FIG.
In -8, the wheel shaft rotation speed detecting means 52a, 52
The rotation speeds of the left front wheel axle 30a, the right front wheel axle 30b, the left rear wheel axle 46a, and the right rear wheel axle 46b are detected by b, 56a, and 56b, respectively, and the signals are input to the control means 16. Further, the steering operation state of the steering wheel 72, that is, the rotation angle and the rotation speed of the steering shaft 72a are detected by the steering detection means 74.

In step S-9, based on the steering operation state of the steering wheel 72 detected by the steering detecting means 74, the expected turning of the vehicle is performed by the turning radius commanding means 62 included in the control means 16. A set speed ratio R, which is a ratio between the turning outer wheel shaft rotation speed of the vehicle and the turning inner wheel shaft rotation speed of the vehicle, which is a radius, is set.

In step S-10, the control means 1
6 based on the rotational speeds detected by the wheel axle rotational speed detectors 52a, 52b, 56a, and 56b by the speed ratio calculator 66 included in the rotational speed ratio between the turning outer wheel axle rotational speed and the turning inner wheel axle rotational speed. Is calculated.

In steps S-11 and S-13, the speed ratio comparing means 70 included in the control means 16
The calculated speed ratio β is compared with the set speed ratio R.

If the calculated speed ratio β is smaller than the set speed ratio R, the process proceeds to step S-12. In this case, since the turning radius is larger than the set turning radius, the rotation of the inside wheel is reduced. Pressure setting means 1 of control means 16
In 9, the pressure increase is corrected by the pressure setting signal correction means 76, and the set pressure is increased, and the brake hydraulic pressure control valve 64 a,
The output pressure to the turning inside wheel axle brake of 64b, 68a, 68b becomes high. As a result, the braking force of the turning inner wheel shaft is increased, and the speed ratio β becomes a value within the range of the set speed ratio R. After the pressure increase is corrected in step S-12, the process returns to step S-8.

On the other hand, if the calculated speed ratio β is larger than the set speed ratio R, the process proceeds to step S-14. In this case, since the turning radius is smaller than the set turning radius, the rotation of the turning inner wheel is increased. As described above, the pressure setting is corrected by the pressure setting signal correcting means 76 in the pressure setting means 19 of the control means 16, the set pressure is reduced, and the turning inner wheel shaft brake of the brake hydraulic control valves 64a, 64b, 68a, 68b is reduced. The output pressure to is reduced. As a result, the braking force of the turning inner wheel shaft is reduced, and the speed ratio β becomes a value within the range of the set speed ratio R. After the pressure reduction is corrected in step S-12, the process returns to step S-8.

An allowable range of the upper limit and the lower limit is set for the set speed ratio R. If the calculated speed ratio β is within the allowable range of the set speed ratio R, the pressure setting signal being output is continued, and step S- Return to 2.

When the swing regulating means 80 or 90 is provided, a signal for operating the swing regulating means is output from the control means 16 together with the output of the pressure setting signal.
The swing regulating means 80 or 90 operates to regulate the swing.

As described above, the steering apparatus for a wheeled vehicle according to the present invention, when the refraction angle of the vehicle body becomes the vehicle body refraction limit angle calculated from the relationship between the traveling speed of the vehicle and the position of the center of gravity of the vehicle, the steering turning. The inner wheels are braked by the brakes,
Also, the braking force is controlled. Therefore, since the vehicle is steered by braking the wheels inside the steering turn, the vehicle body may be less refracted, that is, the steering can be performed in a stable vehicle state.

[0050]

According to the steering apparatus for a wheeled vehicle configured according to the present invention, the refraction of the vehicle body during steering is limited to a small extent, and the swing of the wheel with respect to the vehicle body is restricted.
Fluctuations in the position of the center of gravity of the vehicle during steering can be reduced. Further, it is possible to provide a wheeled vehicle that can be steered in a stable vehicle state and can be steered at a higher speed.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing main components of a steering apparatus for a wheeled vehicle configured according to the present invention.

FIG. 2 is a flowchart showing a part of an operation procedure of the steering apparatus for a wheeled vehicle configured according to the present invention.

FIG. 3 is a flowchart showing a part of an operation procedure including another embodiment of the steering apparatus for a wheeled vehicle configured according to the present invention.

FIG. 4A is a diagram illustrating an embodiment of a swing restriction unit as viewed from the rear of a vehicle. (B) is a diagram showing another embodiment of the swing restriction means as viewed from the rear of the vehicle.

FIG. 5A is an explanatory diagram showing the relationship between steering and vehicle center of gravity (CG) in vehicle body refraction steering, as viewed from above the vehicle. (B) is an explanatory view showing the relationship between the steering and the vehicle center of gravity (CG) in wheel steering, as viewed from above the vehicle.

[Explanation of symbols]

2: Front vehicle body 4: Rear vehicle body 6: Connecting means 8: Hydraulic cylinder (actuator) 10: Vehicle body refraction angle detection means 14: Travel speed detection means 16: Control means 17: Refraction angle calculation means 18: Refraction angle comparison means 19: Pressure setting means 34a, 34b, 60a, 60b: Wheel axle brake 52a, 52b, 56a, 56b: Wheel axle rotational speed detecting means 62: Turning radius command means 64a, 64b, 68a, 68b: Brake hydraulic control valve 66: Speed ratio Calculation means 70: Speed ratio comparison means 76: Pressure setting signal correction means 80, 90: Swing regulation means

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Claims (3)

[Claims] 1. A front vehicle body having left and right front wheels, a wheel axle for transmitting power to the left and right front wheels, and a brake for braking the wheel axle, right and left rear wheels, and power for the left and right rear wheels. A rear body including a wheel axle and a brake for braking the wheel axle; connecting means for refractively connecting the front body and the rear body; one end attached to the front body and the other end attached to the rear body A steering device for a wheeled vehicle, comprising a telescopic actuator that refracts and steers the front vehicle body and the rear vehicle body around the coupling means by the actuator. Traveling speed detecting means for detecting a traveling speed of the vehicle; vehicle body refraction angle detecting means for detecting a refraction angle between the front vehicle body and the rear vehicle body; a brake hydraulic pressure control valve for controlling a hydraulic pressure of the wheel axle brake; Means, Control means for calculating a vehicle body refraction limit angle of the vehicle based on a signal from the traveling speed detection means; and a vehicle body refraction limit angle calculated by the refraction angle calculation means and the vehicle body refraction angle detection. Means for comparing the angle of refraction detected by the means with the angle of refraction, and pressure setting means for outputting a pressure setting signal to the brake hydraulic control valve based on the result of comparison by the angle of refraction comparing means. A steering device for a wheeled vehicle. 2. The steering device further includes: a wheel shaft rotation speed detection unit that detects a rotation speed of the wheel shaft; and a steering detection unit that detects an operation state of a steering wheel. A turning commanding a steering turning radius of a vehicle as a set speed ratio which is set based on a signal from the steering detecting means, based on a ratio between a turning outer wheel shaft rotation speed of the vehicle and a turning inner wheel shaft rotation speed of the vehicle. Radius command means, speed ratio calculating means for calculating a ratio between the turning outer wheel shaft rotational speed and the turning inner wheel shaft rotational speed based on a signal from the wheel shaft rotational speed detecting means, and the speed ratio calculating means A speed ratio comparing means for comparing the speed ratio calculated by the above with the set speed ratio, and a pressure setting signal output from the pressure setting means to the brake hydraulic control valve based on a comparison result by the speed ratio comparing means. Pressure to correct The steering apparatus for a wheeled vehicle according to claim 1, further comprising a force setting signal correction unit. 3. The wheel according to claim 1, further comprising a swing restricting means for restricting the swing of the front wheel or the rear wheel, which is swingably attached to the front vehicle body or the rear vehicle body. Vehicle steering system.