JPH11115444A - Air suspension device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a suspension device of a three-axle vehicle having large maximum loading capacity and two front axles which can start easily even on a low friction road surface. SOLUTION: Two front axles 1, 2 and a rear 33 are provided by air springs, and solenoid valves 12, 13, 14, 23 are provided in an air circuit supplying air to the air springs 6a, 6b, 6c. Vehicle height sensors 20, 20a, 21 and air pressure sensors 22, 22a, 30 are provided on a front 1, a front and rear axle 2, and a rear axle 33, respectively, and are connected to a controller 25 together with a switch 26 which turns on and off a start auxiliary mechanism and a vehicle height adjusting switch 31 to control a vehicle height and a shaft weight by the controller 25.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention
The present invention relates to a suspension device for a vehicle having an axle, each of which is suspended by an air spring.

[0002]

2. Description of the Related Art Vehicles having two front axles and one rear axle are commonly used, and all or a part of the front axle, the front and rear axles, and the rear axle are suspended by air springs. Vehicles are also known.

[0003]

In a vehicle having two front axles, when the maximum load capacity is to be increased,
Ideally, each axle and tire should be able to share the maximum value of the load allowed by strength and regulations. For example, referring to FIG. 3, in the case of a large truck having an arrangement of two front shafts and one rear shaft, assuming a total vehicle weight of about 23 tons, the front front shaft 1
The front and rear axle 2 has the same axle weight of about 6.5 tons, and the rear axle has an
It is generally conceivable to share tons. (Actually, the weight of one shaft cannot exceed 10 tons).

However, in the case of a truck having a large weight difference between a loaded vehicle and an empty vehicle due to the actual vehicle layout,
At the time of loading, there is a problem that the axle load of the front-rear shaft 2 becomes larger than the axle load of the front front axle 1 and the maximum load capacity decreases. Further, even if such an equalization mechanism is used in which the suspension of the front and front shafts 1 and the front and rear shafts 2 is connected by the link 34 or the like so as to have the same shaft weight, the rear shaft 33 which is the drive shaft when the vehicle is idle is used. There is a problem that the weight becomes small and the starting ability on a low friction road such as a wet road surface is reduced.

On the other hand, when the maximum load is increased, the spring constant becomes large, and a load whose load is determined by its volume is light in weight, causing problems such as load damage and ride comfort.

Here, reference numerals 32, 35 and 36 denote leaf springs, C denotes a cab, and N denotes a carrier.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a suspension device which has a large maximum load capacity, does not have a reduced starting capability on a low friction road when the vehicle is empty, and has no load damage.

It is another object of the present invention to provide a suspension device that is comfortable to ride even when loaded lightly without any damage to the load.

[0009]

According to the present invention, there is provided a suspension system for a three-axle vehicle having two front axles, each of which is suspended by an air spring. An air reservoir to be supplied is connected to an air spring of a first shaft and a second air spring through a check valve.
The air spring of the shaft is connected to the air spring of the shaft via the second solenoid valve and the third solenoid valve, respectively, and the air spring of the first shaft and the air spring of the second shaft are connected via the first solenoid valve. The air spring of the rear shaft is connected to the air reservoir by a pneumatic circuit via a check valve and a fourth solenoid valve, and a vehicle height sensor is connected to the first shaft, the second shaft and the rear shaft, respectively. And an air pressure sensor are attached,
The first, second, third, and fourth solenoid valves, the first shaft, the second shaft, and the rear shaft vehicle height sensor, and the air pressure sensor each control the air pressure of the air spring by an electric circuit. And a switch for opening and closing a start assist mechanism for facilitating the start of the vehicle and a vehicle height adjustment switch for increasing and decreasing the vehicle height on the first axis, the second axis, and the rear axis side by an electric circuit. Connected to control device.

According to the present invention, the control device includes:
During normal running, the first solenoid valve is opened, and the second, third and fourth solenoid valves are opened.
The second solenoid valve is closed, and when displaced from a preset vehicle height, the second, third and fourth solenoid valves are controlled and restored,
When the start assist mechanism switch is on, the first solenoid valve is closed, the second and third solenoid valves are controlled, and the first axis, the second axis, and the second axis are controlled by signals from the air pressure sensor and the vehicle height adjustment switch. The second to fourth solenoid valves are opened and closed so as to supply or discharge air from an air spring of the rear shaft.

The present invention is configured as described above, and the axle load of the front two axles can be equalized irrespective of the vehicle layout, so that the maximum load capacity can be increased. Also,
By controlling the air pressure of the first shaft and the second shaft, the shaft load of the rear shaft, which is the driving shaft, can be controlled, so that the vehicle can be easily started on a low friction road and the air pressure of the rear shaft is sensed. By doing so, it is possible to prevent the axle weight of the rear shaft from becoming excessive,
Since the vehicle height on the axle, the second axle and the rear axle can be increased or decreased, the cargo handling work can be efficiently and easily performed.

Further, the weight of the suspension can be reduced by adopting the air spring, which contributes to increasing the maximum load capacity.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. In FIG. 1, a front front shaft 1, which is a first shaft, is movably supported in a vertical direction by a suspension arm 3 having a front end pivotally mounted. Is interposed.

Similarly, the front-rear shaft 2, which is the second shaft, is movably supported in the up-down direction by a suspension arm 4 having a front end pivotally mounted. A spring 6b is interposed.

Further, the rear shaft 33 is supported by the suspension arm 5, and an air spring 6c is interposed between the suspension arm 5 and a frame (not shown).

The air springs 6a and 6b are connected to an air reservoir 17 via a check valve 16 by air circuits c and b having a second solenoid valve 13 and a third solenoid valve 14, respectively. The air spring 6a and the air spring 6b are simultaneously connected via the first solenoid valve 12 by the air circuit a.

The air spring 6c is connected to the air reservoir 27 via the check valve 28 and the fourth solenoid valve 23 by an air circuit d. Here, the air reservoir 2
The air reservoir 8 may use an air reservoir 17, or the two air reservoirs 17 and 28 may be connected by an air circuit.

The air spring 6a has an air pressure sensor 22, and the air spring 6b has an air pressure sensor 22a.
An air pressure sensor 30 is connected to each of the air springs 6c.
, A vehicle height sensor 21 is attached to the rear axle 33.

Then, the first to third solenoid valves 12, 13,
14 and the fourth solenoid valve 23, vehicle height sensors 20, 20a,
A control device 25 for controlling the solenoid valves 12, 13, 14 and 23 by an electric circuit to control the air pressure of the air springs and the air pressure sensors 22, 22a and 30 respectively.
It is connected to the. Further, when the tire 33a of the rear axle is slippery on a low friction road, the starting assist mechanism switch 26 for increasing the axle weight and facilitating the start and the vehicle height on the front front axle 1, the front and rear axle 2 and the rear axle 33 side are adjusted. Increase / decrease vehicle height adjustment switch 3
1 is connected to the control device 25. Here, reference numeral 1a
Indicates a front-axis tire and 2a indicates a front-axis tire.

The operation will be described below with reference to FIG. At the time of operation, the control device 25 first reads a signal from each sensor (step S1). During normal running when the switch 26 of the start assist mechanism is off, the control device 2
5 determines whether or not the vehicle height has reached a predetermined value based on signals from the vehicle height sensors 20 and 20a provided on the front front shaft 1 and the front and rear shaft 2 (step S2). If NO, that is, if the vehicle height has not reached the predetermined value, the air from the air springs 6a and 6b is supplied or discharged to adjust the front vehicle height (step S3). That is, when the vehicle height is high, the air is discharged from the atmosphere opening port 13a of the second electromagnetic valve 13, and when the vehicle height is low, the second electromagnetic valve 13 is opened to open the air spring 6a.
6b to a predetermined height. If YES, it is determined whether the rear vehicle height has reached a predetermined height (step S4). If NO, the vehicle height adjustment switch 31 is set to O
It is determined whether it is N (step S9). If no,
The vehicle height of the rear axle 33 is adjusted by opening and closing the fourth solenoid valve 23 (step S11), and if YES, that is, if the vehicle height adjustment switch 31 is on either side of increasing or decreasing the vehicle height Is increased or decreased until the vehicle is turned off (step S1).
0). If the front-rear shaft 2 bounces while the vehicle is at a predetermined height during traveling, the air of the air spring 6b of the front-rear shaft 2 is opened to the air spring 6a of the front front shaft 1. Although the air is supplied from the vehicle height sensor 20, the air from the air spring 6a is discharged through the second solenoid valve 13 by the signal from the vehicle height sensor 20, so that the vehicle height of the front front shaft 1 is kept constant, When 2 is a rebound, the air is supplied to the air spring 6a and the vehicle height is kept constant.

If the vehicle height is at the predetermined value, it is confirmed whether the start assist mechanism switch 26 is on (step S5). If NO, the process returns. It is determined whether the air pressure of the rear shaft 33 is within a predetermined value and there is a margin for pressure increase (step S6). In the case of NO, the second and third solenoid valves 13 and 14 are closed, the first solenoid valve 12 is opened to communicate the air springs 6a and 6b,
The front front shaft 1 and the front / rear shaft 2 are equalized and set to coaxial weight to return to the normal running state (step S8), and YES is returned.
Then, the first solenoid valve 12 is closed, and the second solenoid valve 13
Is opened to supply air to the air spring 6a, the third solenoid valve 14 is opened to discharge air from the air spring 6b of the front-rear shaft 2, reduce the axial load of the front-rear shaft 2, and return (step S7). The rear shaft 33 is increased in axle weight so that the torque of the drive shaft is sufficiently transmitted to the road surface via the tire 33a. Therefore, even on a low friction road surface, the tire can be prevented from spinning and can easily start.

The controller 25 prevents the axle load of the rear axle 33 from exceeding the axle load allowed by strength and regulations due to the turning on of the switch 26 of the starting assist mechanism, which is safe.

[0023]

The present invention is configured as described above,
It has the following excellent effects. (1) Since the axle load of the front two axles can be equalized regardless of the vehicle layout, the maximum load capacity can be increased. (2) By controlling the air pressure of the front and front shafts and the front and rear shafts, the shaft load of the rear shaft can be controlled, and the vehicle can be easily started on a low-friction road with a light load. (3) The vehicle can be held horizontally irrespective of the loading amount, and the axle load can be prevented from becoming excessive, which is safe. (4) The weight of the suspension can be reduced by adopting the air spring, and a larger load capacity can be obtained. (5) Since the vehicle height can be adjusted, loading and unloading on the platform is easy.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram of a suspension showing one embodiment of the present invention.

FIG. 2 is a flowchart of the control in FIG. 1;

FIG. 3 is a diagram showing an example of the related art.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Front front axis (1st axis) 2 ... Front-back axis (2nd axis) 3, 4, 5 ... Suspension arm 6a, 6b, 6c ... Air spring 12 ... 1st Solenoid valve 13 ... second solenoid valve 14 ... third solenoid valve 16 ... check valve 17,27 ... air reservoir 20,20a, 21 ... vehicle height sensor 22,22a, 30 ... Air pressure sensor 23 ... Fourth electromagnetic valve 25 ... Control device 26 ... Start assist mechanism switch 31 ... Vehicle height adjustment switch 33 ... Rear shaft

Claims (2)

[Claims] 1. A suspension device for a three-axle vehicle having two front axles, each of which is suspended by an air spring, wherein an air reservoir for supplying air to the air spring is provided via a check valve. The first axis air spring and the second axis air spring are connected to the first axis air spring and the second axis air spring via a second solenoid valve and a third solenoid valve, respectively, by an air circuit. And are connected by a pneumatic circuit via a first solenoid valve,
The air spring on the rear shaft is connected to the air reservoir through a pneumatic circuit via a check valve and a fourth solenoid valve.
A vehicle height sensor and an air pressure sensor are attached to the shaft, the second shaft, and the rear shaft, respectively, and first, second, third, and fourth solenoid valves, and vehicles for the first shaft, the second shaft, and the rear shaft. A high sensor and an air pressure sensor are connected by an electric circuit to a control device for controlling the air pressure of the air spring, and a switch for opening and closing a start assist mechanism for facilitating the start of the vehicle, a first shaft, and a second shaft.
A suspension device characterized in that a vehicle height adjusting switch for increasing and decreasing the vehicle height on the shaft and rear shaft side is connected to the control device by an electric circuit. 2. The control device according to claim 1, wherein the first electromagnetic valve is opened during normal running, the second, third, and fourth electromagnetic valves are closed, and the second electromagnetic valve is displaced from a preset vehicle height. The third and fourth solenoid valves are controlled and restored, and when the start assist mechanism switch is ON, the first solenoid valve is closed, the second and third solenoid valves are controlled, and the vehicle height adjustment switch is 2. The suspension device according to claim 1, wherein the second to fourth solenoid valves are configured to open or close to supply or discharge air from the first, second and rear shaft air springs in response to the signal.