JPH10911A - Drive force adding device of rear two axle vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To set widely a range in which a drive force can be applied and, at the same time, to suppress a reduction in a drive performance to a little degree by independently controlling in response to the internal pressure of an air spring and vehicle weight the internal pressure of the air spring for suspending a rear front axle and the internal pressure of the air spring for suspending a rear rear axle in driving force applied condition. SOLUTION: A rear front axle 17 is hanged with a leaf spring 21, and an air spring 23. Furthermore, the rear rear axle 18 is hanged with a leaf spring 22, and an air spring 24 respectively. The rear front axle 17 constitutes a drive shaft while the rear rear axle 18 constitutes a follower shaft. The front and the rear air springs 23 and 24 are communicated with a communication pipe 27, and the vehicle height is detected with a bearing sensor 41 attached on the rear rear axle 18, and at the same time, the computer 50 controls a levelling valve 40 in accordance with the detection output to control a supply and an exhaust of air of a front and rear air springs 23 and 24. As a consequence, the range of the vehicle weight for applying a drive force can be set widely, and, at the same time, a lowering of an inclination of an asendable slope can be suppressed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a driving force applying device for a rear two-axle vehicle, and more particularly to a rear front axle comprising a driven shaft by discharging air from an air spring of a suspension device having a driven shaft. The present invention relates to a driving force adding device for a two-axle wheel after increasing the axle weight of a shaft to increase the driving force of a driving wheel.

[0002]

2. Description of the Related Art For example, Japanese Utility Model Publication No. 27444/1990 discloses that the air load of an air spring of a suspension device that suspends a rear shaft consisting of a driven shaft is exhausted to increase the axial load of a rear front shaft consisting of a driving shaft. A driving force applying device for a two-axle vehicle is disclosed in which the driving force of the driving wheels is increased in such a manner.

FIG. 16 shows changes in the internal pressure of the air spring on the driving shaft side and the air spring on the driven shaft side of such a driving force applying device. When a driving force is applied, the air from the air spring on the driven shaft side is exhausted to lower the internal pressure, and most of the vehicle weight is borne by the drive shaft.
Therefore, as the vehicle weight increases, the internal pressure of the air spring on the drive shaft side gradually increases. When the internal pressure of the air spring on the drive shaft side reaches the limit pressure, at this point, the application of the driving force is released, and the air spring on the drive shaft side communicates with the air spring on the driven shaft side. Return to the state.

[0004]

As described above, in the conventional driving force applying device, the communication between the air spring on the driving shaft side and the air spring on the driven shaft side is cut off, and the air from the air spring on the driven shaft side is discharged. I do. When the loaded load increases in such a state, the air spring on the drive shaft side is compressed and the vehicle height is reduced.Therefore, air is supplied to the air spring on the drive shaft side by a leveling valve, thereby increasing the internal pressure. I have to.

Accordingly, the internal pressure of the air spring on the drive shaft side reaches the limit load with the vehicle weight slightly loaded from the empty vehicle, and in this state, the application of the driving force must be released. FIG. 17 shows a change in the slope that can be climbed with respect to the vehicle weight of the driving force applying device.

As is apparent from these graphs, in the conventional driving force applying device, the range of vehicle weight to which driving force can be added is very narrow as is apparent from FIG. 16, and in the case of a large truck, the load capacity is large. It was up to about 4 tons. Further, there is a problem that when the state is switched from the driving force applied state to the driving force applied released state, the ascending slope is greatly reduced as shown in FIG. 17 and the driving performance is largely changed.

SUMMARY OF THE INVENTION The present invention has been made in view of such a problem, and it is possible to set a wide range in which a driving force can be added, and to change a driving force applied state to a driving force applied released state. It is an object of the present invention to provide a driving force adding device for a rear two-axle vehicle capable of suppressing a decrease in driving performance at the time of switching.

[0008]

SUMMARY OF THE INVENTION The present invention increases the axle weight of a rear front shaft consisting of a drive shaft by discharging air from an air spring of a suspension device that suspends a rear shaft consisting of a driven shaft. In the driving force applying device for a two-axle wheel, the driving force of the air spring that suspends the rear front shaft and the internal pressure of the air spring that suspends the rear shaft are added to the vehicle weight in the driving force applied state. The present invention relates to a driving force adding device for a rear two-axle vehicle, wherein the driving force adding device is controlled independently of each other.

Another aspect of the present invention is to increase the axle weight of a rear front shaft comprising a drive shaft by discharging air from an air spring of a suspension device which suspends a rear shaft comprising a driven shaft to increase the driving force of a drive wheel. In the driving force applying device for a two-axle vehicle, when the vehicle weight increases in the driving force applied state, the air spring that suspends the rear shaft while maintaining the internal pressure of the air spring that suspends the rear front shaft substantially constant. The present invention relates to a driving force adding device for a rear two-axle vehicle, characterized in that the internal pressure is controlled to increase.

Still another aspect of the present invention is to increase the axle weight of a rear front shaft comprising a drive shaft by discharging air from an air spring of a suspension device which suspends a rear shaft comprising a driven shaft to thereby increase the driving force of a drive wheel. After trying to increase 2
In a driving force applying device for an axle, when the vehicle weight increases in a driving force applied state, the internal pressure of the air spring that suspends the rear front shaft and the internal pressure of the air spring that suspends the rear shaft are gradually increased. The present invention relates to a driving force applying device for a rear two-axle vehicle, which is controlled.

The rear front shaft and the rear rear shaft may be respectively suspended on the vehicle body side by leaf springs, and an air spring may be interposed between the free end side of each leaf spring and the vehicle body.

[0012]

FIG. 1 shows a rear two-axis track provided with a driving force applying device according to an embodiment of the present invention. A cab 11 is mounted on a front end side of a body frame 10 of the truck. On the other hand, the body frame 1
The loading platform 12 is mounted on the rear side of the cab 11 on the zero.

The front end of the body frame 10 is supported by front wheels 14. The front wheels 14 are the same steered wheels as the conventional ones. On the other hand, a rear portion of the vehicle body 10 is supported by a rear front wheel 15 and a rear rear wheel 16. The rear front wheel 15 is composed of drive wheels,
Are composed of driven wheels. That is, the output torque of the engine is transmitted only to the rear front wheels 15, and the rear wheels 16 support the load. The rear front wheel 15 and the rear rear wheel 16 are mounted on both ends of a rear front shaft 17 and a rear rear shaft 18, respectively.

The rear front shaft 17 and the rear rear shaft 18 are suspended from the vehicle body frame 10 by leaf springs 21 and 22, respectively, as shown in FIG. The front end portions of these leaf springs 21 and 22 are constituted by eyeball portions, and such eyeball portions are connected to eyeball pins of a bracket on the body frame 10 side. On the other hand, air springs 23 and 24 are interposed between the body frame 10 and the rear end portions of the leaf springs 21 and 22 which are free ends.

Next, the structure of a driving force applying device using air springs 23 and 24 of a suspension device for suspending the driving shaft 17 and the driven shaft 18 on the vehicle body frame 10, respectively, will be described. As shown in FIGS. 2 and 3, the air spring 23 on the rear front shaft 17 side and the air spring 2 on the rear shaft 18 side
4 is communicated with each other by a communication pipe 27. In the middle of the communication pipe 27, a cut valve 28 is provided.
Are connected, and the communication between the front and rear air springs 23 and 24 by the communication pipe 27 is interrupted as necessary. In addition, the left and right air springs 23 on the rear front shaft 17 side are communicated by a communication pipe 29 in front of the cut valve 28, and the left and right air springs 24 on the rear shaft 18 side are communicated by a communication pipe 30 behind the cut valve 28. I try to make it. These communication pipes 29,
30 are connected to pressure sensors 31 and 32 for detecting the pressures of the air springs 23 and 24, respectively.

An exhaust valve 34 is further connected to the left and right cut valves 28. Pilot valves 35 and 36 for supplying signal pressure to the cut valve 28 and the exhaust valve 34 are connected to signal ports of the cut valve 28 and the exhaust valve 34, respectively.

Next, an air tank 45 for storing compressed air.
A leveling valve 40 is connected between the and the communication pipe 29. The opening and closing of the leveling valve 40 is controlled in conjunction with the detection of a leveling sensor 41 for detecting the distance between the shaft 18 and the vehicle body later. The leveling sensor 41 has a lever 42,
2 are connected to the shaft 18 later via a link 43.

The air spring 24 on the shaft 18 is provided with an air supply valve 46 for supplying air from the air tank 45 without passing through the leveling valve 40.
The air spring 24 is provided through such an air supply valve 46.
Are connected to the air tank 45.

Further, a computer 50 is provided to control such a driving force applying device. A switch 51 for adding a driving force to the computer 50
Is connected. The pressure sensors 31 and 32 and the leveling sensor 41 are connected to the input side of the computer 50. The computer 50 controls the leveling valve 40, the pilot valves 35 and 36, and the air supply valve 46.

As described above, in the rear two-axis track according to this embodiment, the rear front shaft 17 is suspended by the leaf spring 21 and the air spring 23, and the rear shaft 18 is suspended by the leaf spring 22 and the air spring 24. The rear front shaft 17 is a drive shaft and the rear
Are constituted by driven shafts. The front and rear air springs 23 and 24 are communicated by a communication pipe 27, the vehicle height is detected by a leveling sensor 41 attached to the shaft 18 later, and the computer 50 controls the leveling valve 40 according to the detected output. Thus, the supply and discharge of air to the front and rear air springs 23 and 24 are controlled.

The pressures of the front and rear air springs 23 and 24 are detected by pressure sensors 31 and 32, respectively, and input to the computer 50. A cut valve 28 for controlling the communication and shutoff of the front and rear air springs 23 and 24 is provided in the communication pipe 27, and the opening and closing of such a cut valve 28 is detected by the pilot valve 35 by the pressure sensors 31 and 32. It is controlled according to.

The computer 50 controls the pilot valve 35
Is controlled, a signal pressure is supplied from the pilot valve 35 to the cut valve 28, and the cut valve 28
7 and the rear air spring 2
4 is connected to the exhaust valve 34 via the cut valve 28.
The computer 50 then controls the pilot valve 36
Is switched, the signal pressure is supplied to the exhaust valve 34 through the pilot valve 36, and the air of the air spring 24 is discharged through the exhaust valve 34.

The air is discharged from the air spring 24 by operating a switch 51 provided in the driver's seat.
When a signal is supplied to the computer 50, the computer 5
The above-described exhaust operation is performed only when the condition of 0 is the driving force added state. That is, when the switch 51 provided in the driver's seat is turned on, the communication between the front and rear air springs 23 and 24 is cut off when the vehicle weight detected by the pressure sensors 31 and 32 is smaller than a predetermined value. By discharging the air from the air spring 24 on the side, a driving force adding operation is performed.

FIG. 4 shows a state in which the driving force applying device does not operate and the normal leveling function of the leveling valve 40 is operating. That is, the front and rear air springs 23 and 24 are communicated via the cut valve 28, and the supply of air to the front and rear air springs 23 and 24 is controlled by the leveling valve 40.
The vehicle height is kept at an appropriate height.

FIG. 5 shows a state in which the operation for switching to the driving force applied state is performed. The front and rear air springs 23 and 24 are cut off by the cut valve 28, and the air from the rear air spring 24 is cut off. Is discharged through the cut valve 28 and the exhaust valve 34. At this time, air is supplied to the air spring 23 on the rear front shaft 17 side by the leveling valve 40 at the same time, so that a decrease in the vehicle height due to the internal pressure of the air spring 23 is suppressed.

FIG. 6 shows a state in which the switching to the driving force applied state has been completed.
When the air of No. 4 is discharged, the cut valve 28 is shut off and the exhaust valve 34 is kept closed.

According to such a driving force adding device, the driving force of the driving wheel 15 on the driving shaft 17 side is increased when the vehicle weight is low or the vehicle is half loaded with a small loading load, whereby the starting by the driving wheel 15 is started. Performance and running performance can be improved.

When switching to the driving force added state, FIG.
As shown in FIG. 3, the air is exhausted from the air spring 24 on the shaft 18 side by the exhaust valve 34 and the leveling valve 4
0, the air supply to the air spring 23 on the rear front shaft 17 side can be performed almost simultaneously, thereby reducing the axial load of the rear shaft 18 and the rear front shaft 1
7, it is possible to shorten the moving time of the axle load for increasing the axle load. Such operation is achieved by controlling the pilot valve 36 and the leveling valve 40 simultaneously by the computer 50.

Further, since the pressures of the front and rear air springs 23 and 24 are detected by the pressure sensors 31 and 32, respectively, the axial load applied to the rear front shaft 17 and the rear shaft 18 is reduced by these sensors 31 and 32. By reading the output of 32 with the computer 50, it is possible to easily grasp it, and it is possible to surely prevent the axle load applied to the rear front shaft 17 and the rear shaft 18 from exceeding the regulation.

In addition, the driving force applying apparatus is controlled by the computer 50 so as to have the characteristics shown in FIG. 8 based on the flowchart shown in FIG.
That is, when the driving force adding switch 51 connected to the computer 50 is turned on, the pressures of the front and rear air springs 23 and 24 are detected by the pressure sensors 31 and 32, respectively. It is determined whether or not the value of S shown in FIG. 8 is exceeded.
When the vehicle weight is S or less, the state is switched to the driving force added state. In this operation, the cut valve 28 is shut off as described above, and the air in the air spring 24 is exhausted through the cut valve 28 and the exhaust valve 34, and the internal pressure of the air spring 24 is exhausted until it reaches the value of b. Performed by Moreover, the air spring 24 for applying such a driving force is used.
Is stopped when the internal pressure of the air spring 23 on the drive shaft 17 side exceeds a.

In the above control, when the vehicle weight increases in the driving force added state, the computer 50 controls the opening and closing of the leveling valve 40 to reduce the internal pressure of the air spring 23 that suspends the rear front shaft 17 to a constant value a. While keeping
The opening and closing of the air supply valve 46 is controlled by the computer 50, and the internal pressure of the air spring 24 of the shaft 18 is controlled so as to be gradually increased later.

Therefore, by performing such control, the operating range of the driving force applying device with respect to the vehicle weight can be set wide as shown in FIG. Also, the change in the internal pressure of the air spring at the time of switching from the driving force applied state to the driving force applied released state is shown by a solid line in FIG. 8, and the change in the slope that can be climbed with respect to the change in vehicle weight at this time is shown in FIG. It becomes as shown in. As is clear from this graph, there is a feature that the decrease in the slope that can be climbed at the time of canceling the driving force is reduced and the width of the performance difference in the state of canceling the driving force can be set narrow.

The driving force applying device is a computer 5
Since the pressures of the front and rear air springs 23 and 24 can be arbitrarily adjusted by 0, the change in the internal pressure of the air springs 23 and 24 may be made to have a characteristic as shown in FIG. This characteristic is intended to further reduce the difference in axial load between the front and rear air springs 23, 24. Alternatively, as shown in FIG. 11, the computer 50 may control the internal pressures of the front and rear air springs 23 and 24 to increase substantially linearly in the driving force applied state.

In general, in the case of a trunnion suspension vehicle, as shown in FIG. 12A, since the rear front wheel and the rear rear wheel rotate around the suspension shaft to perform an equalizing operation, the rear rear wheel rides on a step. Occasionally, the running performance does not deteriorate much. The rear two-axle wheel according to the present embodiment
Is opened, the air moves from the rear air spring 24 to the front air spring 23 when the rear wheel 16 rides on the step, so that the rear front shaft 1
The decrease in the axial load on the 7 side is small, and the running performance is not deteriorated.

On the other hand, when the cut valve 28 is closed to apply a driving force, the movement of air from the air spring 24 on the driven shaft 18 to the air spring 23 on the driving shaft 17 is stopped. As shown in FIG. 12C, the equalizing operation is not performed. This allows the drive shaft 1
The axial load on the 7 side will be reduced.

However, in the vehicle according to the present embodiment, the driving force adding device is controlled by the computer 50 so as to have the characteristics shown in FIG. 13, and the vehicle weight for canceling the driving force added state is adjusted. To the value of S. FIG. 14 shows such a change in the drive shaft weight ratio with respect to the height of the step on which the rear wheel 16 rides on the vehicle. In particular, by setting the vehicle weight S (see FIG. 13) at the time of canceling the driving force addition to an appropriate value, the drive shaft 1 does not perform the equalizing operation as shown in FIG.
Drive axle weight ratio of 7 (ratio of drive axle weight to total vehicle weight)
Is minimized, it is possible to prevent the traveling performance from deteriorating when the wheel 16 rides on a step later.

When the difference between the axle load on the drive shaft 17 and the axle load on the driven shaft 18 is large, the driven wheels 16 may be locked on a road surface having a low friction coefficient during braking, and the vehicle behavior may be disturbed. However, such a state can be effectively avoided by the driving force applying device. In particular, the front and rear air springs 23 in the driving force applied state by the driving force applying device,
By controlling the internal pressure at 24 so as to have the characteristics shown in FIG. 13, the above problem can be more reliably prevented.

The present invention is also applicable to a suspension device as shown in FIG. In this suspension device, a rear front shaft 17 and a rear shaft 18 are attached to support beams 55 and 56, respectively.
Are suspended from the frame 10 by the air springs 23, respectively, whereas the support beam 56 on the rear side is suspended from the frame 10 via the front and rear air springs 24. The rear front shaft 17 and the rear shaft 18 are connected to a bracket 60 attached to the frame 10 via torque rods 57 and 58, respectively.

In such a suspension device,
By controlling the supply and discharge of air to and from the front air spring 23 and the supply and discharge of air to and from the rear air spring 24, respectively, it becomes possible to perform the same operation as in the above-described embodiment, and to add a driving force. The range of the vehicle weight in which the driving force is applied can be set wide, and the change in the characteristics at the time of switching from the driving force addition state to the driving force addition release state, in particular, a decrease in the slope that can be climbed can be suppressed to a low level.

[0040]

As described above, according to the present invention, the internal pressure of the air spring that suspends the rear front shaft and the internal pressure of the air spring that suspends the rear shaft are controlled independently according to the vehicle weight in the state where the driving force is applied. It is like that.

Accordingly, by separately controlling the air springs on the rear and front shafts and the air springs on the rear and rear shafts in the driving force applied state, it is possible to arbitrarily set the range in which the driving force can be applied. In addition, it is possible to arbitrarily adjust a change in driving performance when switching from the driving force applied state to the driving force applied released state.

According to another aspect of the present invention, when the vehicle weight increases in the driving force applied state, the internal pressure of the air spring that suspends the rear shaft is increased while the internal pressure of the air spring that suspends the rear front shaft is kept substantially constant. Is controlled as follows.

Therefore, by performing such control, the range of the vehicle weight in which the driving force is added can be set wide, and the performance and performance when switching from the driving force added state to the driving force added released state can be set. In particular, it is possible to suppress a decrease in the slope that can be climbed to a low level.

According to still another aspect of the present invention, when the vehicle weight increases in the driving force added state, the internal pressure of the air spring that suspends the rear front shaft and the internal pressure of the air spring that suspends the rear shaft are gradually increased. Is controlled as follows.

Therefore, even with such a driving force adding device, it is possible to set a wide range in which the driving force can be added, and to improve the driving performance when switching from the driving force addition state to the driving force addition release state. It is possible to keep the decrease small.

[Brief description of the drawings]

FIG. 1 is a side view of a truck including a driving force applying device.

FIG. 2 is a perspective view of a main part showing a suspension system for a rear front shaft and a rear shaft.

FIG. 3 is a piping diagram of the driving force applying device.

FIG. 4 is a piping diagram showing a normal running state.

FIG. 5 is a piping diagram illustrating a switching state to a driving force applied state.

FIG. 6 is a piping diagram in a state where the state has been switched to a driving force added state.

FIG. 7 is a flowchart showing an operation of switching to a driving force applied state.

FIG. 8 is a graph showing an operation of the driving force applying device.

FIG. 9 is a graph showing a change in a slope that can be climbed by the driving force applying device.

FIG. 10 is a graph showing a control characteristic of another embodiment.

FIG. 11 is a graph showing control characteristics according to still another embodiment.

FIG. 12 is an essential part side view showing an equalizing operation when a rear wheel rides on a step.

FIG. 13 is a graph showing a relationship between a vehicle weight and an internal pressure of an air spring.

FIG. 14 is a graph showing a relationship between a step height and a drive shaft weight.

FIG. 15 is a side view of a main part of a suspension device according to another embodiment.

FIG. 16 is a graph showing characteristics of a conventional driving force applying device.

FIG. 17 is a graph showing a change in a slope that can be climbed by a conventional driving force applying device.

[Explanation of symbols]

 Reference Signs List 10 body frame 11 cab 12 carrier 14 front wheel 15 rear front wheel (drive wheel) 16 rear rear wheel (driven wheel) 17 rear front shaft (drive shaft) 18 rear rear shaft (driven shaft) 21, 22 leaf spring 23, 24 air spring 27 communication Pipe 28 Cut valve 29, 30 Communication pipe 31, 32 Pressure sensor 34 Exhaust valve 35, 36 Pilot valve 40 Leveling valve 41 Leveling sensor 42 Lever 43 Link 45 Air tank 46 Air supply valve 50 Computer 51 Switch 55 Support beam (front) 56 Support Beam (rear) 57 Torque rod (front) 58 Torque rod (rear) 60 Bracket

Claims (4)

[Claims] An air spring of a suspension device for suspending a rear shaft consisting of a driven shaft discharges air from the air spring to increase the axle weight of a rear front shaft consisting of a driving shaft to increase the driving force of a driving wheel. In the driving force applying device for a two-axle vehicle, the internal pressure of the air spring that suspends the rear front axle and the internal pressure of the air spring that suspends the rear axle are independently controlled according to the vehicle weight in the driving force applied state. A driving force adding device for a rear two-axle vehicle, characterized in that: 2. The driving force of a driving wheel is increased by discharging the air from an air spring of a suspension device that suspends a rear shaft composed of a driven shaft to increase the axial load of a rear front shaft composed of a driving shaft. Then, when the vehicle weight increases in the driving force applied state, the internal pressure of the air spring that suspends the rear axle while maintaining the internal pressure of the air spring that suspends the rear front axle is increased. A driving force applying device for a rear two-axle vehicle, wherein the driving force is controlled to increase. 3. The driving force of a driving wheel is increased by discharging the air from an air spring of a suspension device that suspends a rear shaft consisting of a driven shaft to increase the axial load of a rear front shaft consisting of a driving shaft. In the driving force adding device for the two-axle wheel, when the vehicle weight increases in the driving force added state, the internal pressure of the air spring that suspends the rear front shaft and the internal pressure of the air spring that suspends the rear shaft are gradually increased. A driving force adding device for a rear two-axle wheel, wherein the driving force is controlled so as to be controlled. 4. The vehicle according to claim 1, wherein the rear front shaft and the rear rear shaft are respectively suspended on the vehicle body side by leaf springs, and an air spring is interposed between the free end side of each leaf spring and the vehicle body. Claim 1
2. A driving force adding device for a rear two-axle vehicle according to item 1.