JP3087628B2 - Axle load distribution adjustment device for rear two-axle vehicle - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for adjusting the distribution of a load applied to a driving wheel axle and an idle wheel axle in accordance with a loaded weight in a rear two-axle vehicle in which a rear wheel axle includes a driving wheel axle and an idle wheel axle. It is about.

[0002]

2. Description of the Related Art In a rear two-axle vehicle such as a truck in which a rear wheel axle is composed of a driving wheel axle and an idle wheel axle, the load shared by the driving wheel axle is sufficiently ensured in order to prevent slipping of the driving wheels. Although it is necessary, if the setting is made such that a sufficient shared load acts when the vehicle is empty, there is a problem that the shared load of the drive wheel axle during loading is excessive, and an appropriate shared load is obtained when loading. If it is set, there is a problem that the shared load of the driving wheel axle when the vehicle is empty is insufficient.

[0003] As a solution to such a problem, for example, Japanese Utility Model Laid-Open No. 60-84408 or Japanese Utility Model Laid-Open No. 60-169.
As described in Japanese Patent Publication No. 011, it is known that an air suspension is used as a suspension device for suspending an idle wheel axle, and the air pressure of the air suspension is adjusted to adjust a shared load acting on a drive wheel axle. I have.

[0004]

However, the technique disclosed in Japanese Utility Model Laid-Open Publication No. 60-84408 controls the operation of a solenoid valve in accordance with the load on the drive wheel axle detected by a self-weight meter. When the load is small, air is discharged from an air spring that suspends the idler wheel axle, so that an expensive weight meter is required.

The technique disclosed in Japanese Utility Model Laid-Open Publication No. 60-169011 controls the operation of the solenoid valve based on the detection result of a switch and a pressure switch that are operated manually or by shifting to the reverse gear, thereby suspending the idle wheel axle. Since the air is discharged from the air spring, manual operation is required, which is inconvenient.

SUMMARY OF THE INVENTION It is an object of the present invention to automatically set a large load allotment of a driving wheel axle when the vehicle is empty, and to cause a slip of the driving wheel when the vehicle is started on a sloping road or running on a low friction road when the vehicle is empty. The present invention is to provide an axle load distribution adjusting device for a rear two-axle vehicle that can effectively prevent the occurrence of the axle load.

[0007]

According to a first aspect of the present invention, there is provided a rear two-axle vehicle in which one of two rear axles is constituted by a driving wheel axle and the other is constituted by an idle wheel axle. An air suspension for suspending the idler wheel axle by a spring, a drive shaft suspension for suspending the drive wheel axle, and detecting an increase in the vehicle height of the drive wheel axle due to a decrease in the loaded weight; a pressure adjusting means for reducing the internal pressure, the lowest of the air spring
And a minimum pressure limiting means for limiting the pressure .

[0008]

[0009]

[0010]

[0011]

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIG.
This will be described with reference to FIGS. FIG. 1 is a side view showing a part of a rear two-axle, and as shown in FIG.
A rear front shaft 2 as a drive wheel axle is suspended via a leaf spring type suspension 3, and a rear shaft 4 as an idle wheel axle is suspended via a trailing arm type air suspension 5.

The trailing arm type air suspension 5 has a spring hanger 6 fixed to the chassis frame 1. One end of a trailing arm 8 is rotatable on the spring hanger 6 via a connecting pin 7. It is connected to.

The trailing arm 8 supports the shaft 4 later through a U-bolt 9, and the other end of the trailing arm 8 is provided with an air spring 10. In the figure, 11 is a driving wheel, 12 is an idle wheel, 13
Reference numerals 1 and 132 denote front and rear brackets fixed to the chassis frame 1. Reference numeral 13 denotes a leaf spring whose front end is pivotally attached to the front bracket 131 and extends rearward.
4 is the rear end of the leaf spring 13 and the rear bracket 13
Reference numeral 15 denotes a shock absorber, which is erected and pivotally mounted between the two, 2 denotes a shock absorber, and 16 denotes a bump stopper that prevents a collision of the rear shaft 4 with the chassis frame 1.

The air spring 10 later supports the shaft 4 so as to be vertically displaceable with respect to the chassis frame 1. The air spring 10 has a leveling valve as air pressure adjusting means as shown in FIG. (Air supply / discharge valve) 20 is connected via an air pipe 19, a surge tank 18 and an air pipe 17. This leveling valve 20 is attached to the chassis frame 1 side.

As shown in FIG. 2, the leveling valve 20 has an air introduction port 21 and this air introduction port 21.
An air supply port 22 for supplying the air flowing from the air supply port to the surge tank 18 and an air discharge port 23 for discharging the air flowing from the air supply port 22 are provided. Is connected via an air dryer 27, an air pipe 26, an air tank 25, and an air pipe 24. The air discharge port 23 has a supply valve 3 as a minimum pressure limiting means for limiting the minimum pressure of the air spring 10.
0 is connected through an air pipe 29, and the supply valve 30 prevents the air from being discharged beyond a predetermined minimum pressure.

Further, the leveling valve 20 is provided as shown in FIG.
When the valve 32 provided in the valve body 31 is opened against the urging force of the coil spring 33, the air flowing into the valve body 31 from the air introduction port 21 is provided as shown in FIG. Is supplied to the surge tank 18 through the air supply port 22 and the air pipe 19,
When the valve 34 provided in the valve body 31 is opened against the urging force of the coil spring 35, the air supply port 22 is opened.
The air that has flowed into the valve body 31 through the valve 34 flows through the air discharge port 23, the air pipe 29 and the supply valve 30, and is exhausted to the atmosphere.

Further, the leveling valve 10 is a valve 3
An opening / closing member 36 for opening and closing the valve 2 and the valve 34; a rotating shaft 37 for swingably supporting the opening / closing member 36; and a lever 38 having a base end fixed to the rotating shaft 37. An axle 40 of the rear front shaft 2 is connected to a distal end of the lever 38 via a rod 39 as shown in FIG.

A magnet valve 42 is connected to the air tank 25 via an air pipe 41. The magnet valve 42 is for releasing the air in the air tank 25 to the atmosphere, and is opened and closed by a signal from a controller (not shown).

The air tank 25 includes an air spring 10
When the pressure detected by the pressure sensor 43 reaches a preset upper limit value, the magnet valve 42 is changed from “closed” to “closed” by a signal from a controller (not shown). When the pressure detected by the pressure sensor 43 reaches a preset lower limit, the magnet valve 42 is switched from "open" to "closed" by a signal from a controller (not shown). . The above-described magnet valve 42, pressure sensor 43, and controller (not shown) constitute maximum pressure limiting means.

In the embodiment of the present invention configured as described above, when the chassis frame 1 descends due to the flexure of the suspension accompanying an increase in the loading weight, the valve body 31 of the leveling valve 20 also descends, and the lever 38 Figure 3
Rotate clockwise. When the lever 38 rotates clockwise in FIG. 3, the valve 32 changes from the "closed" state to the "open" state.
It switches to the state of. As a result, the air in the air tank 25 flows through the air pipe 24, the air introduction port 21, the air supply port 22 and the air pipe 19, and flows through the surge tank 18.
To increase the air pressure of the air spring 10.

When the chassis frame 1 rises with a decrease in the load weight, the valve body 31 of the leveling valve 20 also rises, and the lever 38 rotates counterclockwise in FIG. Then, when the lever 38 rotates counterclockwise in FIG. 3, the valve 34 switches from the "closed" state to the "open" state. As a result, the air in the surge tank 18 is released from the air pipe 19, the air supply port 22, and the air discharge port 2.
3. The air is exhausted into the atmosphere through the air pipe 29 and the supply valve 30, and the air pressure of the air spring 10 is reduced.

At this time, since the valve 32 is in the "closed" state, the air flowing from the air supply port 22 does not flow through the air introduction port 21 and flow back to the air tank 25.

At this time, if the air pressure in the surge tank 18 falls below a predetermined minimum pressure, the supply valve 30 is switched from the "open" state to the "closed" state. As a result, the minimum air pressure of the air spring 10 can be maintained at or above a predetermined minimum pressure.

As described above, in one embodiment of the present invention, when the load weight increases, the air pressure of the air spring 6 of the shaft 4 increases later, and when the load weight decreases, the air pressure of the air spring 6 decreases. The distribution of the load applied to the rear front axle 2 and the rear rear axle 4 of the rear two-axle vehicle can be appropriately adjusted according to the loaded weight, and the height from the rear front axle (drive wheel axle) 2 to the chassis frame 1 can be adjusted. In addition, the height from the rear wheel (idle axle) 4 to the chassis frame 1 can be kept constant.

Further, in one embodiment of the present invention, when the load weight is reduced, the air pressure of the air spring 10 is reduced, so that the load sharing of the drive wheel axle when the vehicle is idle can be automatically increased, and It is possible to effectively prevent the drive wheels 11 from slipping when the vehicle is running on a sloping road or a low friction road when the vehicle is empty. In particular, since the air pressure of the air spring of the idle wheel axle is controlled according to the vehicle height fluctuation of the drive wheel axle, it is possible to secure and distribute an appropriate load load to the drive wheel axle, and it is highly reliable. The structure can be simple, inexpensive and excellent in practicality.

Further, in one embodiment of the present invention, the leveling valve 20 is used as an internal pressure adjusting means for adjusting the internal pressure (air pressure) of the air spring 10, so that the axle load distribution is automatically adjusted at low cost by mechanical control. be able to.

In one embodiment of the present invention, the leaf spring suspension 3 is used as the drive shaft suspension for suspending the drive wheel axle, so that it is not necessary to use an air suspension as the drive shaft suspension, and it is inexpensive and reliable. An axle load distribution adjusting device for a rear two-axle vehicle with high reliability can be obtained.

In one embodiment of the present invention, when the pressure detected by the pressure sensor 43 reaches a preset upper limit, the magnet valve 42 is changed from "closed" to "open" by a signal from a controller (not shown). Since the air tank 25 is switched and the air in the air tank 25 flows through the air pipe 41 and the magnet valve 42 and is discharged into the atmosphere, the air pressure in the air tank 25 does not exceed the upper limit. As a result, air having a pressure equal to or higher than the maximum limit pressure is not supplied to the air spring 10, so that damage to the air spring 10 can be prevented.

Further, in one embodiment of the present invention, since the supply valve 30 prevents the air from being discharged beyond a predetermined minimum pressure, the air pressure of the air spring 6 becomes lower than the minimum pressure even when the vehicle is idle. Therefore, it is possible to prevent a decrease in ride comfort.

In the above embodiment, the internal pressure of the air tank 25 is adjusted by using the supply valve 30, the pressure sensor 43, and the controller (not shown) as the maximum pressure limiting means. For example, when the internal pressure of the air tank 25 is set to be high because it is necessary to share the same pressure with the brake), a reducing valve 50 for limiting the supply pressure on the leveling valve 20 side to a set value or less is interposed in the air pipe 24 to provide the maximum pressure. Restriction means may be used.

[0032]

As described above, according to the first aspect of the present invention, it is possible to automatically set a large load sharing of the drive wheel axle when the vehicle is empty, and to start on a sloping road or to reduce a low friction road when the vehicle is empty. It is possible to effectively prevent the occurrence of slip of the drive wheels during the traveling of the vehicle. Also, even when the vehicle is empty, the air pressure is
Without lowering the ride comfort.
Can be.

[0033]

[0034]

[0035]

[Brief description of the drawings]

FIG. 1 is a side view showing a part of a rear two-axle according to an embodiment of the present invention.

FIG. 2 shows an embodiment of the present invention, and is a schematic configuration diagram of an air pressure adjusting device that adjusts an air pressure of a trailing arm type air suspension according to a loaded weight.

FIG. 3 shows one embodiment of the present invention, and is a cross-sectional view illustrating a schematic configuration of a leveling valve.

[Explanation of symbols]

1 ... chassis frame, 2 ... rear front axle (drive wheel axle), 3
... leaf spring type suspension, 4 ... rear axle (idle wheel axle), 5 ... trailing arm type air suspension, 10 ... air spring, 18 ... surge tank, 20 ... leveling valve, 25 ... air tank, 28
... air compressor, 40 ... axle, 43 ... pressure sensor.

Claims (1)

(57) [Claims] 1. A rear two-axle vehicle in which one of two rear axles is constituted by a drive wheel axle and the other is constituted by an idle wheel axle, wherein an air suspension for suspending the idle wheel axle by an air spring, and suspending the drive wheel axle. Drive shaft suspension, internal pressure adjusting means for detecting an increase in the vehicle height of the drive wheel axle due to a decrease in the loaded weight, and reducing the internal pressure of the air suspension, and a minimum pressure for limiting the minimum pressure of the air spring. An axle load distribution adjusting device for a rear two-axle vehicle, comprising pressure limiting means.