JPH0511048Y2 - - Google Patents

Description

[Detailed explanation of the invention] (Industrial application field) By changing the vehicle body load applied to the vehicle wheel axle,
This improves drivability on muddy ground and snowy roads.

(Prior Art) Vehicles with three or more axles, such as large trucks and buses, i.e., a large truck 1 as shown in FIG. There is a vehicle in which driving force from an on-vehicle engine is transmitted to the rear and front wheel axles 3 to drive the vehicle.

Therefore, in such a vehicle, the vehicle body load applied to the rear wheels is shared between the rear front wheel axle 3 and the rear rear wheel axle 4 to support the vehicle body 7.

However, the driving force F of the vehicle is due to the tires 5 and the road surface 6.
It is the product of the friction coefficient μ and the load P applied to the rear and front wheel axles 3.

Therefore, on low-μ roads such as muddy and snowy roads where the friction coefficient μ is small, the driving force F may become smaller than the vehicle running resistance force F′, which may cause the vehicle to become unable to travel. , the axle load of the rear front wheel axle 3, which is the driving wheel axle, is increased to increase the driving force and the vehicle is able to escape from the muddy area.However, after escaping, if the vehicle runs at medium to high speeds with the axle load of the rear front wheel axle 3 increasing. ,
There was a problem in that the strength safety factor of the rear front wheel axle 3 decreased and the possibility that the coaxial axle 3 was damaged increased.

(Purpose of the invention) The present application proposes that when the above-mentioned vehicle enters a low μ road,
A part or most of the vehicle body load applied to the rear rear wheel axle 4 is transferred to the rear front wheel axle 3, which is the driving wheel axle, and the load P on the rear front wheel axle 3 is increased to increase the driving force F. Even if the driver forgets to perform an operation to return the vehicle body load on the rear front wheel axle 3 after the vehicle has escaped from a snowy road or the like, the load is automatically returned to its original state.

(Structure of the invention) In the present invention, the rear axle is composed of a plurality of axles consisting of a driving wheel axle and a non-driving wheel axle, which suspend the vehicle body by a fluid suspension, and the fluid suspension of the non-driving wheel axle In the vehicle, the vehicle body support load of the drive wheel axle is increased by reducing the pressure of the drive wheel axle, the control valve means being connected to the fluid suspension of the non-drive wheel axle to control supply and discharge of fluid; a pressure sensor for detecting the pressure in the fluid suspension mounted on the vehicle; a vehicle speed sensor for detecting the vehicle speed of the vehicle; and a vehicle speed sensor for detecting the vehicle speed of the vehicle; A manually operated set switch that reduces the pressure, and once it is detected that the pressure detected by the pressure sensor reaches a predetermined maximum pressure when the set switch is operated, the pressure in the fluid suspension of the non-driving wheel axle is maintained. a first control means for operating the control valve means; and a first control means for controlling the control valve means by the set switch and the first control means when it is detected that the vehicle speed detected by the vehicle speed sensor is equal to or higher than a set value. The gist of the present invention is a vehicle body load adjustment safety device for a wheel axle, which is characterized by comprising a second control means for disabling the vehicle body load.

According to the invention, when the manually operated set switch is operated, the control valve means is actuated to reduce the pressure in the fluid suspension of the non-driving wheel axle, thereby reducing the vehicle body support load on the non-driving wheel axle. The vehicle body support load on the wheel axle increases, which results in an increase in the pressure in the fluid suspension of the drive wheel axle. Once the first control means detects from the detection output of the pressure sensor that the pressure within the fluid suspension of the driving wheel axle has reached a predetermined maximum pressure, the first control means thereafter controls the fluid suspension of the non-driving wheel axle. Since the control valve means is operated to maintain the pressure of The pressure within the fluid suspension will be maintained at the predetermined maximum pressure.

Therefore, according to the present invention, when the manually operated set switch is operated, the pressure in the fluid suspension of the drive wheel shaft can be increased to a predetermined maximum pressure and maintained at that state, and the pressure can be maintained at a predetermined maximum pressure. It is possible to reliably improve the driving force of a vehicle such as in a vehicle.

In particular, in the present invention, when the vehicle speed detected by the vehicle speed sensor exceeds a set value, the second control means disables the control of the control valve means by the set switch and the first control means, so that The vehicle does not run at medium to high speeds with a high vehicle body load applied to the drive wheel axle, and problems such as damage to the drive wheel axle can be prevented.

(Example) A detailed description will be given with reference to the drawings. FIG. 2 shows an embodiment of the present invention, in which symbols 2L and 2R are provided on the front wheel axle 2 shown in FIG. 1, and are arranged approximately symmetrically with respect to the center of the vehicle to suspend the vehicle body 7. It is an air suspension which is a fluid suspension. Reference numeral 8L or 8R is a leveling valve installed in a passage that communicates the air suspension 2L or 2R with the supply valve 10 disposed downstream of the air tank 9, which is a fluid pressure source. When the air suspensions 2L and 2R are compressed due to an increase in the load on the vehicle body 7 and the gap between the vehicle body 7 and the front wheel axle 2 becomes smaller than the set value, the leveling valves 8L and 8R are used to supply air from the air tank 9 to the air suspension 2L or 2R. Air is supplied to inflate the air suspensions 2L and 2R to maintain the gap between the vehicle body 7 and the front wheel axle 2 at a set value.

Also, if the gap between the vehicle body 7 and the front wheel axle 2 becomes larger than the set value, the air suspension 2L or 2R
This air is discharged into the atmosphere from the leveling valve 8L or 8R to maintain the gap at the set value. Reference numeral 11 indicates the rear wheel axle (rear-front wheel axle 3 and rear-rear wheel axle 4).
It is a leveling valve (generally referred to as ``3''), and is approximately the same in structure and function as the leveling valves 8L and 8R disposed on the front wheel axle 2.

Codes 3LF and 3LR are on the left side of the rear front wheel axle 3, 3
RF and 3RR are air suspensions arranged on the right side of the rear front wheel shaft 3, 4L on the left side of the rear rear wheel shaft 4, and 4R on the right side of the rear rear wheel 4, respectively.

Code 12 is air suspension 3LF, 3
A normally open pressure switch that turns on when the air pressure of LR, 3RF, and 3RR exceeds the set value.
It forms a pressure sensor.

Reference numeral 13 is provided in the driver's seat (not shown), and the power supply 1 is turned on by turning on a set switch 14 which has a built-in pilot lamp 15.
This is a solenoid valve that operates when energized with 6. The same solenoid valve 1
3 is a first port A that communicates with the air tank 9 via the leveling valve 11 and the supply valve 10; B is a second port that communicates with the air suspensions 4L and 4R; Each has a third port C that communicates with a pressure reducing valve 17 that releases air to the atmosphere. Also, the solenoid valve 13 is B- when energized.
C. When the power is off, A and B are connected. Pressure reducing valve 1
When the set switch 14 is turned ON, an electromagnetic coil 17' for operating the pressure reducing valve 17 is energized via a self-holding relay 18, which will be described later, and is activated. The pressure reducing valve 17 is energized and ports D and E are energized and energized and ports FE and E are communicated with each other. In addition, the solenoid valve 13
The pressure reducing valve 17 constitutes a control valve means.

A self-holding relay 18, which constitutes the first control means, is arranged at a power supply contact H, a contact K connected to the pressure reducing valve 17, and a meter plate 19 on the driver's seat. It consists of a pilot lamp 20 that indicates that the pressure is being reduced and a contact J that is connected to an excitation coil 21 that prevents energization to the pressure reducing valve 17. Contacts H and K are normally connected by a spring force (not shown). has been done.

22 receives a signal from a speed sensor 23 which serves as a vehicle speed sensor, and when the vehicle 1 reaches a speed equal to or higher than a specified value (15 km/h in this embodiment),
Speed control 24 serving as second control means
This is a safety relay that cuts off the power supply circuit of this device using the current from the power source, and is normally a closed circuit. Also, the code 27 is air suspension 4R, 4
This is a throttle valve that controls the L air pressure so that it does not drop suddenly.

The operation of this device will be explained. When the vehicle 1 enters a muddy or snowy road, the driver turns on the set switch 14, and the current flows as follows: power supply 16 → safety relay 22 → set switch 14 → *1, *2, *
3 *1 The pilot lamp lights up to indicate that the set switch is ON *2 Operate the solenoid valve 13 to connect B and C.

*3 Self-holding relay contact H→contact K→pressure reducing valve 17 is activated and D-E communicate.

Air suspension 4L and 4 for rear rear wheel axle 4
The air in R is connected to B-C of solenoid valve 13 and pressure reducing valve 1.
It is released into the atmosphere through D-E of 7. Therefore, the air pressure in the air suspensions 4L and 4R decreases, and the load acting on the rear wheel axle 4 decreases. Therefore, the decrease in the vehicle body load mentioned above is due to the air suspension 3LF, 3LR, 3 of the rear front wheel axle 3.
When the air suspension moves to RF and 3RR and the air suspension is compressed to reduce the gap between the vehicle body 7 and the rear front wheel axle 3, the leveling valve 11 operates to transfer high pressure air from the air tank 9 to the air suspensions 3LF, 3LR, While supplying to 3RF and 3RR, it operates so that the gap between the vehicle body 7 and the rear front wheel axle 3 becomes a set value.

When the vehicle body load on the rear rear wheel axle 4 moves to the rear front wheel axle 3 by a set amount, the amount of movement is applied to the air spring 3LF,
It is detected by changes in air pressure in 3LR, 3RF, and 3RR (in this case, the air pressure becomes higher). That is, the pressure switch 12 is turned on when the air pressure in the air suspensions 3LF, 3LR, 3RF, and 3RR reaches a set value.

Then, the current flows from the set switch 14 to the pressure switch 12 to the excitation coil 21 of the self-holding relay 18, and the contacts of the self-holding relay 18 change from H-K to H.
-J, the power to the pressure reducing valve 17 is cut off, ports F-E of the pressure reducing valve 17 are communicated, and port D is closed, so that air discharge from the air suspensions 4R and 4L is stopped, and the The transfer of the vehicle body load from the rear wheel axle 4 to the rear front wheel axle 3 is completed.

On the other hand, the current of the self-holding relay 18 flows in the order of the set switch 14 → the contact H of the self-holding relay 18 → the contact J → *1, *2 *1 the pilot lamp 20 of the meter cluster 19 *2 the diode 25 → the excitation coil 21, The pressure reducing valve 17 continues to be prevented from being energized.

Also, the self-holding relay 18 is activated when the air suspensions 3LF, 3LR, 3RF, and 3
Pressure inside RR fluctuates and pressure switch 12 turns on.
Even if -OFF is repeated, the action of the excitation coil 2 prevents the pressure reducing valve 17 from being energized. Furthermore, when the vehicle transitions to steady driving after escaping from a muddy area, etc., the driver does not restore the shift of the vehicle body load on the wheel axles, that is, this device transfers the vehicle body load from the rear front axle 3 to the rear axle 4. If the amount moved by the operation is not returned, the strength and safety factor of the rear front wheel axle 3 will decrease. The speed control 24 controls the excitation coil 26 of the safety relay 22 based on the signal from the speed sensor 23.
The solenoid valve 13 is energized and the normally closed circuit is interrupted by the excitation force of the excitation coil 26.
The energization is cut off, and the ports A and B of the solenoid valve 13 are made to communicate with each other to restore the wheel axle load to its original state.

Also, as shown in Figure 3, the operating mode of the speed control 24 is from 0 to 15km/h when the vehicle speed increases.
4 when the vehicle speed is decelerating from 15 km/h or more with the safety relay turned on and the safety relay closed circuit.
It is set so that it does not turn on until the Km/H has been reached.

Although air was used as the fluid in this embodiment, it is also possible to obtain substantially the same effect as in this embodiment by using air and liquid together and changing the air pressure in the air suspension by moving the liquid. .

According to this embodiment, by reducing the pressure of the air in the air suspension attached to some wheel axles of a vehicle having a plurality of wheel axles on which the vehicle body is suspended by air suspension, the air suspension is applied to other wheel axles. The driving force of the vehicle can be increased by increasing the vehicle body load, and even if the driver forgets to return the vehicle body load to the rear front wheel axle 3 after escaping from a muddy area, the vehicle body load is automatically returned to its original state. Therefore, the effect of preventing damage to the rear and front wheel axles 3 is achieved.

(Effects of the invention) As described above with the embodiments, according to the invention, when the manually operated set switch is operated, the pressure in the fluid suspension of the drive wheel axle is increased to a predetermined maximum pressure. For example, if this predetermined maximum pressure is set to a value that corresponds to the maximum load specified by law, the load on the drive wheel axle can be easily increased to the maximum load specified by law. This has the advantage that it is possible to reliably obtain the maximum usable drive performance with simple operations and easily improve running performance when driving on low μ roads. Furthermore, when the vehicle speed exceeds the set value, the control of the control valve means by the set switch and the first control means becomes invalid, so the vehicle runs at medium to high speeds with a higher vehicle body load than during normal driving on the drive wheel axle. This has the advantage of being safe and highly practical, since problems such as damage to the drive wheel axle can be prevented.

[Brief explanation of the drawing]

FIG. 1 is a side view of the entire vehicle, FIG. 2 is an air and electric circuit diagram according to an embodiment of the present application, and FIG. 3 is a diagram showing the operating mode of the speed control. 2L, 2R, 3LF, 3LR, 3RF, 3RR, 4
L, 4R...Air suspension, 3...Rear front wheel axle, 4...Rear rear wheel axle, 11...Leveling valve, 12...Pressure switch, 13...Solenoid valve, 1
7...Reducing valve, 18...Self-holding relay, 22...
...Safety relay.

Claims (1)

[Scope of utility model registration request] A rear axle is constituted by a plurality of axles consisting of a driving wheel axle and a non-driving wheel axle, which suspend the vehicle body by means of fluid suspension, and the fluid suspension of the non-driving wheel axle is depressurized to reduce the pressure of the driving wheel axle. In a vehicle configured to increase a vehicle body support load, the control valve means is connected to the fluid suspension of the non-driving wheel axle to control supply and discharge of fluid, and the fluid suspension mounted on the driving wheel axle includes: a pressure sensor for detecting the pressure of the vehicle; a vehicle speed sensor for detecting the vehicle speed of the vehicle; a manually operated set switch that operates the control valve means to reduce the pressure in the fluid suspension of the non-driving wheel axle; Once it is detected that the pressure detected by the pressure sensor reaches a predetermined maximum pressure when the set switch is operated, the control valve means is actuated to maintain the pressure in the fluid suspension of the non-driving wheel axle. a second control means for disabling control of the control valve means by the set switch and the first control means when it is detected that the vehicle speed detected by the vehicle speed sensor is equal to or higher than a set value; A vehicle body load adjustment safety device for a wheel axle, comprising: