JPH0834328A - Brake device for rear-two-axle vehicle - Google Patents

Abstract

PURPOSE:To prevent the wheel of rear rear axle from early locking in the case where the load of the rear rear axle becomes light as a result of shifting the load of the axle from the rear rear axle to the rear front axle. CONSTITUTION:The braking force of the wheel of a rear rear axle 2 is decreased by a load sensing valve 4, based on the detection signal (displacement) of the load sensor 3, by arranging the load sensor 3, which detects the change of load applied to the rear wheel side based on the average value of the displacement of the rear front axle 1 and the rear rear axle 2, between the rear front axle 1 and the rear rear axle 2 of a rear-two-axle car equipped with an axle load distributor for shifting the load of axle from the rear rear axle 2 to the rear front axle 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a brake device for a rear two-axle vehicle having an axle load distribution device for moving axle load from a rear axle to a rear axle. The present invention relates to a brake device for a rear two-axle vehicle, which prevents the wheels from locking early.

[0002]

2. Description of the Related Art For example, a trunnion type rear suspension is used as a rear suspension of a rear two-axle vehicle. In this rear suspension, the load is applied equally to the front and rear axles or distributed at a predetermined ratio. However, when only one rear shaft, for example, only the rear front shaft is used as the drive shaft, the load ratio is changed to change the axial load ratio of the rear front shaft, which is the drive shaft (shared load).
When the value of "reduces", there is a risk of slipping when driving on a bad road or a slope. Similarly, when the vehicle is vacant, if the axial load on the rear front shaft, which is the drive shaft, decreases, the required driving force may not be secured on the rear front shaft.

Therefore, the present applicant has filed Japanese Patent Application No. Hei 5-1401.
In No. 08, "Axial load distribution method and device used for rear two-axle rear suspension" was proposed. This proposal distributes the shared load of the rear two axes within the allowable range,
The axle weight of the drive axle can be increased within a range in which the axle weight of the rear-rear axle is avoided, and the start is ensured when the vehicle is empty and lightly loaded.

[0004]

SUMMARY OF THE INVENTION The present invention is to improve a brake device for a rear two-axle vehicle equipped with the above-mentioned axle load distributing device. That is, the ratio of the rear-front axle weight to the rear-rear axle weight is approximately 1: 1 when loaded, whereas when the axle weight moves from the rear-rear axle to the rear-front axle when the vehicle is empty or lightly loaded, for example, It becomes 1.50: 1 and changes. Therefore, in a brake device for a rear two-axle vehicle equipped with the above-mentioned axle load distributing device, if the braking force (braking force) is distributed on the basis of the loaded state, the axle load will be applied to the rear and rear axles when the vehicle is empty or lightly loaded. Despite being light, a large braking force is applied, which may cause the wheels of the rear and rear axles to lock early.

The present invention prevents the wheels of the rear-rear axle from being prematurely locked when the axle load of the rear-rear axle is reduced as a result of moving the axle load from the rear-rear axle to the rear-rear axle. I did 2 more
An object is to provide a braking device for an axle.

[0006]

In order to achieve the above object, the invention of a brake device for a rear two-axle vehicle according to claim 1 is an axial load distribution device for moving the axial load from a rear rear shaft to a rear front shaft. It is characterized in that it is equipped with a load sensing valve for controlling the braking force of the rear and rear axles according to the rear axle weight of the rear two-axle vehicle.

The invention of a brake device for a rear two-axle vehicle according to a second aspect of the invention is a rear wheel for a rear two-axle vehicle, comprising a shaft load distribution device for moving the axial load from the rear rear shaft to the rear front shaft. It is characterized by comprising a sensor that detects a change in the load applied to the side and a pressure control valve that controls the braking force of the rear-rear axle based on the detection signal of the sensor.

As the sensor, a vehicle height sensor for detecting a change in the load applied to the rear wheels by a change in the vehicle height, a load sensor for detecting a change in the load acting on the rear front axle, rear rear axle, or the like, or A tire air pressure sensor that detects the change in air pressure of the tire on the rear wheel side is preferable.

[0009]

According to the first aspect of the present invention, when the vehicle is empty or lightly loaded, the load sensing valve controls the braking force acting on the wheels of the rear and rear axles to be small (the wheel of the rear and rear axles is controlled). Make the braking force smaller than the braking force of the front and rear axle wheels).

According to the second aspect of the present invention, when the sensor detects a change in the load applied to the rear wheel side when the vehicle is empty or lightly loaded, the pressure control valve is rearwardly moved based on the detection signal of the sensor. The control is performed so that the braking force of the axle wheels is reduced.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of a rear two-axle brake device according to the present invention will be described below with reference to FIGS.

FIG. 1 is a piping diagram of an air system part showing a first embodiment of a brake device for a rear two-axle vehicle of the present invention, and FIG. 2 is a load sensing valve part and a rear rear shaft shown in FIG. ,
FIG. 3 is a sectional view of the load sensing valve shown in FIGS. 1 and 2, FIG. 4 is a partially cutaway sectional view of the axial load distribution device, and FIG. FIG. 4 is a partial rear view of the axle weight distribution device of No. 4 viewed from the rear side.

In the first embodiment, the rear rear shaft 2 to the rear front shaft 1
A load applied to the rear wheel side between the rear front axle 1 and the rear rear axle 2 of a rear two-axle vehicle equipped with an axle load distribution device 18 (see FIGS. 4 and 5) for moving the axle load on the rear wheel. Sensor 3 which detects the change of the load by the average value of the displacement of the rear-front axis 1 and the rear-rear axis 2
Is arranged, and the braking force of the wheel of the rear rear axle 2 is controlled by the load sensing valve 4 based on the detection signal (displacement) of the load sensor 3. That is, as shown in FIG. 1, the relay valve 5 for the rear wheels and the rear rear shaft 2
The load sensing valve 4 is arranged between the brake booster 6 and the brake booster 6, and the air pressure sent to the brake booster 6 by the load sensing valve 4 is reduced at a constant ratio.

In FIG. 1, reference numeral 7 is a brake valve, 8 is a brake booster for the rear front shaft 1, 9 is a relay valve for the front wheels, 10 is a brake booster for the front wheels 11, and 12 is a brake booster.
Is a foot pedal, 13 is a brake mechanism for the front wheels 11, 14
Is a brake mechanism for the wheel 15 of the rear-front axle 1 and 16 is the rear-rear axle 2
It is a brake mechanism of the wheel 17 of.

For example, as shown in FIG. 2, the load sensor 3 has a rod 3a installed between a rear front shaft 1 and a rear rear shaft 2, and another end of which is connected to a substantially intermediate point of the rod 3a. The other end of the rod 3b is connected to the lever 4a of the load sensing valve 4.

The load sensing valve 4, as shown in FIG. 3, for example, has a load housing within a valve housing 4b having an inlet port connected to a relay valve 5 and an outlet port connected to a brake booster 6. A plunger 4e operated by a lever 4a via a spring 4c and a lower lever 4d, a piston 4f, and a disc valve 4g are arranged. The change in the rear wheel load is transmitted from the rod 3b to the lever 4a, and as a result, the plunger 4e is pushed up via the load spring 4c and the lower lever 4d, and the piston 4f is also pushed up together with the plunger 4e. On the other hand, when the foot pedal 12 is depressed, the brake valve 7
Air pressure is sent to the load sensing valve 4 via the relay valve 5 and the air pressure works in a direction to push down the piston 4f. When this air pressure overcomes the force pushing up the piston 4f and pushes down the piston 4f, the disc The valve 4g is closed and the pressure reducing operation is started. The decompression starting point of the load sensing valve 4 changes depending on the position of the lever 4a, that is, the magnitude of the load acting on the rear front shaft 1 and the rear rear shaft 2. When the foot pedal 12 is further depressed, the air pressure from the brake valve 7 and the relay valve 5 rises, the piston 4f is pushed up, the disc valve 4g once opens, and the passage to the brake booster 6 opens. Due to this, the air pressure on the upper side of the piston 4f rises, and the piston 4f is pushed down again to reach the equilibrium state. However, due to the area difference between the upper side and the lower side of the piston 4f, the air pressure is reduced at a constant rate and the brake / booster is increased. Sent to 6.

The axial load distribution device 18 is, for example, as shown in FIGS.
As shown in, the rear suspension 19 is equipped.

The rear suspension 19 uses a normal torque rod system, and a leaf spring 23 is attached to the left and right ends of a trunnion shaft 21 fixed to the body frame 20 via U bolts 22.
It is configured to be swingably supported around. The rear front shaft 1 and the rear rear shaft 2 are attached to the front and rear ends of a leaf spring 23 and are held by a torque rod 24. The torque applied to the rear front shaft 1 and the rear rear shaft 2 is transmitted to the vehicle body frame 20 by the torque rod 24.

The axial load distribution device 18 is disposed on the vehicle body frame 21, and has a diaphragm type air spring 26 for supporting the axle hanger 25 of the rear rear axle 2 at its upper end.
Between the air spring 26 and the pressure damper 29, which is in communication with the air spring 26 and to which a pressurized fluid is supplied from a fluid pressure source (not shown) through a protection valve 27 and a pipe 28. The air spring 26 is provided with a pressure adjusting means 30 for adjusting the pressurized fluid flowing therethrough to keep the pressure in the air spring 26 at a predetermined pressure.
A predetermined load is generated, and this load is constantly applied in the lifting direction to the rear-rear shaft 2, so that the shared load of the rear-front shaft 1 is increased and the shared load of the rear-rear shaft 1 is decreased. Configured.

Here, the rear front shaft 1 during loading and emptying
The axial weight ratio of the rear and rear axles 2 changes, for example, as shown in Table 1 below. For comparison, the axial load ratio of the rear front axle 1 and the rear rear axle 2 when the vehicle is vacant when the axle load distributor 18 is not used is also shown.

[0021]

[Table 1] Table 1 Rear front axle 1 axle load (R1) Rear rear axle 2 axle load (R2) R1 / R2 ratio Empty vehicle (without device 18) 2.3t 2.1t 1.10 Empty vehicle (device 18) 2.7t 1.8t 1.50 When loaded (device 18) 9.4t 8.7t 1.08 According to the first embodiment described above, when the foot pedal 12 is depressed, the front valve moves from the brake valve 7. Relay valve 9
Air pressure corresponding to the amount of depression is supplied to the rear wheel relay valve 5. As a result, each relay valve 9,
The air pressure necessary for braking is supplied from 5 to the corresponding brake boosters 10, 8, 6 and the brake mechanism 13, by the hydraulic pressure passing through the brake boosters 10, 8, 6.
Although the front wheels 11 and the rear wheels 15 and 17 are braked by the operation of the wheels 14 and 16, the load sensing valve 4 is applied to the wheel 17 of the rear rear axle 2 based on the rear wheel load detected by the load sensor 3. Controls (decreases) the braking force. That is, when air pressure is sent from the brake valve 7 and the relay valve 5 to the brake boosters 6 and 8, respectively,
The air pressure sent to the brake booster 6 side is reduced by the load sensing valve 4 at a constant ratio compared to the brake booster 8 side, and as a result, the braking force of the wheels 17 of the rear rear axle 2 is rear front. It becomes smaller than the braking force of the wheel 15 of the shaft 1.

Therefore, when the axle load is moved from the rear rear axle 2 to the rear front axle 1 by the axle weight distribution device 18 when the vehicle is empty or lightly loaded, and the axle weight of the rear rear axle 2 becomes light, the rear rear axle 2 The braking force of the second wheel 17 can be reduced to prevent early locking.

Next, a second embodiment of the brake device for a rear two-axle vehicle of the present invention will be described with reference to FIGS.

FIG. 6 shows a second embodiment of a brake device for a rear two-axle vehicle according to the present invention, and is a piping diagram of an air system portion, with the front wheels omitted, and FIG. 7 adopts a vehicle height sensor as a sensor. FIG. 8 is an explanatory view for explaining an example of the arrangement of the sensors in the case where the tire height sensor is used, FIG. 8 is an explanatory view for explaining another example of the arrangement of the vehicle height sensor, and FIG. Explanatory drawing, FIG. 10 is an explanatory view explaining an arrangement example of a sensor when a load sensor is adopted as a sensor, and FIG. 11 is an explanatory view explaining another arrangement example of a load sensor.

In the second embodiment, the rear rear shaft 2 to the rear front shaft 1
A sensor 31 for detecting a change in the load applied to the rear wheel side of a rear two-axle vehicle, which is equipped with an axle load distribution device 18 (see FIGS. 4 and 5) for moving the axle weight, and a detection signal of the sensor 31. A pressure control valve 33 that changes the output pressure by an input controller 32 is provided, and the pressure control valve 33 controls the braking force of the rear rear axle 2. That is, the pressure control valve 33 is arranged between the brake valve 34 and the relay valve 35 on the rear / rear axle 2 side so that the braking force of the brake mechanism 36 on the rear / rear axle 2 side is reduced. There is.

The brake valve 34 is a rear front shaft 1
It is also connected to the side relay valve 37. In addition,
Air pressure is supplied from the tank 38 to the brake valve 34 and the relay valves 35 and 37, respectively. Reference numeral 39 in FIG. 6 denotes a brake mechanism for the rear front shaft 1.

When a vehicle height sensor is used as the sensor 31, a vehicle height sensor 31a is arranged between the rear front shaft 1 and the rear rear shaft 2 as shown in FIG. The vehicle height between the axles 2 is detected, or, as shown in FIG. 8, vehicle height sensors 31a are arranged on the rear front axle 1 and the rear rear axle 2, respectively, and the vehicle heights are detected by these vehicle height sensors 31a. Then, the controller 32 obtains the average value of the vehicle height to detect the change in the loaded load.

When the tire air pressure sensor 31b is used as the sensor 31, for example, the tire air pressure sensor 31b is arranged on the wheel 17 on the rear rear axle 2 side as shown in FIG. To detect changes in.

A load sensor 31c is used as the sensor 31.
10 is adopted, the load sensor 31c is arranged on the trunnion shaft 21 to detect a change in the load, or the load sensor 31c is attached to the rear rear shaft 2 as shown in FIG. Place it and detect changes in payload. Although not shown, the load sensor 31 is attached to the rear front shaft 1.
Alternatively, the load sensors 31c may be provided on the rear front shaft 1 and the rear front shaft 2, respectively.

According to the second embodiment, when the foot pedal is depressed, the amount of depression from the brake valve 34 to the relay valve 37 on the rear front axle 1 side and the relay valve 35 on the rear rear axle 2 side depends on the depression amount. Air pressure is supplied. As a result, the air pressure necessary for braking is supplied from the relay valves 37 and 35 to the corresponding brake mechanisms 39 and 36, but the pressure control valve 33 brakes based on the rear wheel load detected by the load sensor 31.・ Relay from valve 34 ・
The air pressure sent to the valve 35 is reduced, and the brake mechanism 3
Decrease the braking force of 6. That is, when the air pressure is sent from the brake valve 34 to the relay valves 37 and 35, the air pressure sent to the relay valve 35 side is reduced by the pressure control valve 33 as compared with the relay valve 37 side. As a result, the brake mechanism 3 of the rear-rear shaft 2
The braking force of 6 is smaller than the braking force of the brake mechanism 39 of the rear front shaft 1.

Therefore, also in the second embodiment, when the vehicle is empty or lightly loaded, the axial load is moved by the axial load distribution device 18 from the rear rear shaft 2 to the rear front shaft 1, and the shaft of the rear rear shaft 2 is moved. When the weight becomes lighter, the braking force of the brake mechanism 36 of the rear-rear shaft 2 can be reduced to prevent early locking.

[0032]

As described above, according to the present invention,
If the load on the rear-rear axle becomes lighter as a result of moving the axle load from the rear-rear axle to the rear-rear axle, use a load sensing valve or pressure control valve to reduce the braking force on the rear-rear axle wheels. Therefore, it is possible to prevent early locking.

[Brief description of drawings]

FIG. 1 is a piping diagram of an air system portion showing a first embodiment of a brake device for a rear two-axle vehicle of the present invention.

2 is a perspective view of a load sensing valve portion, a rear rear shaft, and a rear front shaft portion shown in FIG. 1. FIG.

FIG. 3 is a sectional view of the load sensing valve shown in FIGS.

FIG. 4 is a partially cutaway sectional view of the axial load distribution device.

5 is a partial rear view of the axial load distribution device of FIG. 4 viewed from the rear side.

FIG. 6 is a piping diagram of an air system portion showing the second embodiment of the brake device for a rear two-axle vehicle of the present invention, with the front wheel side omitted.

FIG. 7 is an explanatory diagram illustrating an arrangement example of sensors when a vehicle height sensor is adopted as a sensor.

FIG. 8 is an explanatory diagram illustrating another arrangement example of the vehicle height sensor.

FIG. 9 is an explanatory diagram illustrating an example of the arrangement of sensors when a tire air pressure sensor is used as the sensor.

FIG. 10 is an explanatory diagram illustrating an arrangement example of sensors when a load sensor is used as the sensor.

FIG. 11 is an explanatory diagram illustrating another arrangement example of the load sensor.

[Explanation of symbols]

 1 rear front shaft 2 rear rear shaft 3 load sensor 4 load sensing valve 5 brake booster 18 axle load distributor 31 sensor 31a vehicle height sensor 31b tire pressure sensor 31c load sensor 33 pressure control valve

Claims (5)

[Claims] 1. A load sensing system for controlling a braking force of the rear and rear axles according to the rear axle weight of a rear two-axle vehicle, which comprises an axle load distribution device for moving the axle weight from the rear and rear axles to the rear and front axles. A brake device for a rear two-axle vehicle, which is equipped with a valve. 2. A sensor for detecting a change in the load applied to the rear wheel side of a rear two-axle vehicle, comprising a shaft load distribution device for moving the shaft load from the rear rear shaft to the rear front shaft, and a detection signal of the sensor. And a pressure control valve for controlling the braking force of the rear-rear axle based on the above. 3. The brake device for a rear two-axle vehicle according to claim 2, wherein the sensor is a vehicle height sensor, and the sensor is a vehicle height sensor between the rear rear axle and the rear front axle or between the rear rear axle and the rear axle. A braking device for a rear two-axle vehicle, wherein the braking device is arranged on each of the front axles, and is configured to detect a change in a load on the basis of a change in vehicle height. 4. The rear two-axle vehicle braking device according to claim 2, wherein the sensor is a load sensor, and the sensor is disposed on either or both of the rear rear shaft and the rear front shaft, or the rear sensor. A braking device for a rear two-axle vehicle, wherein the braking device is arranged on a trunnion shaft between the rear shaft and the rear front shaft. 5. A brake device for a rear two-axle vehicle according to claim 2, wherein the sensor is a tire air pressure sensor, and the sensor is disposed on one of the rear rear axle and the rear front axle, and is loaded. A brake device for a rear two-axle vehicle, characterized in that a change in load is detected by the air pressure of the tire.