JPH08118934A - Controller for start assisting apparatus - Google Patents

Abstract

PURPOSE: To improve a drive force at the start of a vehicle by providing a pneumatic spring for regulating the ground contact pressure of a drive shaft and detecting a change in the axial load by a level sensor for controlling the operation of the pneumatic spring. CONSTITUTION: A drive shaft of two rear shafts is equipped with a start assisting apparatus using a pneumatic spring 505 to increase the ground contact pressure and the traction in the start when a vehicle is started or the like. A controller 800 supplied air to the pneumatic spring 505 when an empty vehicle is stopped, and exhausts the air when the loaded vehicle is stopped or moved with the speed exceeding the set vehicle speed. Also, the air pressure can be regulated within the range of a set value to improve the durability of the pneumatic spring.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for a starting assistance device mounted on a rear two-axle vehicle.

[0002]

2. Description of the Related Art FIG. 10 is an explanatory view showing an outline of a vehicle having two rear axles.
The front tire 21a has a front shaft 21 at the front of the frame 10.
I support. The rear part has two axles 31 and 32 and supports tires 31a and 32a, respectively. Rear two axes 31,3
2 is supported by the frame 10 via a suspension 40, and a load 50 is mounted on the frame 10. Therefore,
The total weight WG of the vehicle 1 including the load 50 is equal to the front tire 21a.
The load WF applied to the rear tires 31a and 32a and the load WR applied to the rear tires 31a are supported by the road surface G. 2 at the rear
By equipping the axles 31 and 32 of the book, the load WR supported by the entire rear part is equal to the load WR supported by the rear front shaft 31.
F and a load WRR supported by the rear rear shaft 32. Therefore, it is possible to configure a vehicle having a larger load while suppressing the maximum load applied to one shaft.

In a rear two-axle vehicle, the rear front shaft 31 is a drive shaft that transmits the driving force from the engine, and the rear rear shaft 32 is a driven shaft that does not transmit the driving force. A so-called 6x2 that simplifies and drives two of the six wheels
It is widespread to compose vehicles. In this 6 × 2 vehicle, the drive tire 31a needs to generate sufficient propulsive force. Therefore, the axial load WR applied to the tire 31a
For F, a load sufficient to generate a necessary propulsive force between the tire and the road surface needs to be distributed. When a load is loaded, the axial load WRF applied to the drive shaft 31 is also sufficiently large, and the tire 31a can generate a necessary propulsive force. However, when there is no load and the tire is not loaded, a sufficient load WRF is not distributed to the drive shaft 31, and the tire 31a may not obtain sufficient propulsive force between the tire 31a and the road surface G. In particular, when the vehicle is started or on a road surface having a small friction coefficient, the tire 31a may slip and the start may be inconvenient.

[0004]

DISCLOSURE OF THE INVENTION The present applicant has filed Japanese Patent Application No.
As No. 184528, a starting assist device for a vehicle that drives one of the two rear axles was proposed. The invention of the above-mentioned application is provided with an air spring that adjusts the ground pressure of the drive shaft, detects a change in the shaft load with a level sensor, and controls the operation of the air spring to reduce the driving force when the vehicle starts. It will improve. However, the air spring is filled with air while the starting assist device is operating. When the vehicle gets on a bump or the like, the drive axle may be suddenly pushed up, and the internal pressure of the air spring may suddenly rise. This causes inconvenience such as damage to the diaphragm of the air spring. The present invention provides a control device for a starting assistance device that solves the above-mentioned problems.

[0005]

The control device of the present invention is, as a basic means, a vehicle equipped with a vehicle start-up assisting device having an air spring on a drive shaft of the rear two shafts. A vehicle speed sensor for detecting, a level sensor for detecting the load on the axle, an air supply source for supplying compressed air to the air spring, a first valve provided in the air pipe for supplying air to the air spring, and an air A second valve for exhausting spring air, a relief valve, and control means for controlling the first valve and the second valve are provided.

[0006]

When the vehicle detects that the vehicle is empty when the vehicle stops, the control means opens the first valve to supply air to the air spring, and when the vehicle exceeds the set vehicle speed or stops. When it is detected that the vehicle is in a loaded state, the second valve is opened to exhaust the air of the air spring. When the pressure in the pipe exceeds the set value, the relief valve opens and drops to the set value.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIGS. 5 to 7 show an outline of a starting assistance device which is installed in a vehicle having a trunnion type suspension and which increases a driving force when the vehicle starts. The vehicle has frames 10 arranged on the left and right of the vehicle body, and supports a drive shaft 200 and a driven shaft 300 via a trunnion type suspension.

A propeller shaft 60 connected to an engine and a transmission arranged at the front of the vehicle transmits power to a differential gear mechanism installed in a differential gear case 70 integrated with the drive shaft 200. The trunnion suspension has a trunnion bracket 110 fixed to the lower surface of the frame 10, and a central portion of a leaf spring 130 is supported on a trunnion shaft rotatably attached to the trunnion bracket 110.

The leaf spring 130 is a laminated leaf spring, and is actually constructed by laminating several to ten leaf springs. The drive shaft 200 has a cylindrical casing 210 in which the drive shaft is rotatably mounted, and drive shaft tires 250 are attached to both ends of the drive shaft. Generally, two drive shaft tires 250 are mounted on each side, four in total. Drive shaft 2
A sliding sheet 220 is provided on the upper portion of the housing 210 of 00 to receive one end of the leaf spring 130.
The leaf spring 130 generates a spring force that presses the drive shaft 200 toward the road surface. A spring retainer 230 is provided on the outside of the sliding sheet 220.

A first torque rod is attached to the lower portion of the housing 210 of the drive shaft via a bracket. This first torque rod is a trunnion bracket 1
It is connected to the second torque rod via a connecting member penetrating through 10. The driven shaft 300 does not transmit the driving force, and rotatably supports the driven shaft tire 350. Driven shaft tire 3
Two 50s are generally installed on one side and four on both sides, but one on each side may be provided.

The central portion of the drive shaft housing 210 projects in the vertical direction to accommodate the differential gear case 70. Bracket 2 is provided on the top of this upper protrusion.
60 is provided and the third torque rod 150 is connected. Since the trunnion type suspension is configured as described above, the center of the trunnion shaft and the drive shaft 200
Distance between centers of trunnion shaft and driven shaft 30
By selecting the center-to-center distance of 0, it is possible to select the ratio of the loads applied to both axes. Further, the drive shaft 200 and the driven shaft 300 circularly move with radii R ₁ and R ₂ , and the distance between the axes changes between D and D 1.

The starting assistance device to which the present invention is applied is disposed above the drive shaft 200. A start-up assisting device, which is generally denoted by reference numeral 500, includes an air spring 505 and its mounting structure. The air spring 505 includes a diaphragm 510 and a piston member 520 disposed below the diaphragm 510.
And an upper plate 530 disposed above the diaphragm 510. The lower part of the diaphragm 510 is attached to the bracket on the drive shaft side. Diaphragm 510
The upper part of is attached to the bracket on the frame side.

For the frame 10 of the vehicle, for example, a channel material having a U-shaped cross section is used, and a frame-side bracket mounting member 570 is fixed to the inside of the frame. A bracket 560 having a lower opening is integrally provided with the mounting member 570, and an upper plate 530 of the air spring 505 is housed and fixed in the bracket 560. The air supply port 540 of the air spring 505 penetrates the bracket 560 and projects upward.

The air supply port 540 is connected to a compressed air supply source through an air supply pipe described later. Large vehicles are equipped with an air compressor and a high-pressure tank for assisting clutches and brakes, so that this compressed air supply source can be used. When the compressed air is not sent to the air spring 505, the drive shaft 200 and the driven shaft 300 are applied with the axial load at the same ratio as that of a normal trunnion suspension. When compressed air is sent to the air spring 505, the diaphragm portion 510 expands,
The drive shaft 200 is biased toward the road surface. The ground pressure applied to the drive shaft tire 250 is increased by this urging force, and the propulsive force generated between the road surface and the road surface is also increased.

Therefore, when the vehicle that requires a large propulsive force is started or the like, by operating the starting auxiliary device, a smooth start can be achieved. The air spring, which is a component of the present start assist device, is particularly susceptible to damage because the diaphragm portion is made of a flexible material. Therefore, the air spring is arranged inside the frame of the vehicle and is covered with a bracket for protection. Further, in the trunnion type suspension, the housing is rotated around the center line of the axle due to the vertical movement of the axle. This rotation causes a displacement between the upper support portion of the air spring and each support portion. However, by disposing the air spring above the housing of the drive shaft, the influence of this displacement can be suppressed to a minimum.

In FIG. 8, an axial load detecting device generally designated by reference numeral 600 has a leaf spring 610 and a level sensor 650 for detecting the amount of displacement of the central portion of the leaf spring 610.

The rear two-axle vehicle includes a first rear axle 200 and a second rear axle 200.
It has a rear axle 300. The first rear axle, which is arranged closer to the front axle, has a casing 210 that contains an axle,
It has a differential gear case 70 and constitutes a drive shaft. The second rear axle 300 has a casing 310,
Configure a driven shaft that does not transmit driving force. Second rear axle 30
Of course, 0 can be used as the drive shaft.

The front end portion of the leaf spring 610 is supported by the rear portion of the differential gear case 70 of the drive shaft 200 via a bracket 620. The rear end portion of the leaf spring 610 is supported by the front portion of the driven shaft casing 310 via the bracket 630. The bush 62 is provided between the bracket 620 and the leaf spring 610.
2 is provided to absorb the twist of the bracket and the leaf spring. Similarly, the bracket 630 of the driven shaft also supports the leaf spring via the bush.

The center portion of the leaf spring 610 is vertically arranged via the attachments 642 and 643 so that the rod 6
Support the lower end of 40. The upper end of the rod 640 is connected to a horizontally extending arm 645, and the arm 645 rotates the shaft 652 of the level sensor 650. The level sensor 650 is fixed to the chassis side of the vehicle and has a function of electrically detecting the rotation amount of the shaft 650 thereof.

Therefore, when the load applied to the drive shaft 200 and the driven shaft 300 changes, the suspension changes, and the vertical distance between the position of the rod mounting portion LC of the leaf spring and the position of the level sensor 650 changes. . Therefore, by electrically detecting the amount of change in this distance,
The axial load applied to the drive shaft 200 and the driven shaft 300 can be detected. According to the suspension type of a vehicle with two rear axles, there is a structure in which the inter-axle distance D changes as the ground clearance of the axles 200 and 300 changes.

By applying the axial load detecting device to the one having this kind of suspension, the axial load detection sensitivity can be improved. That is, in the suspension in which the axial distance D increases as the product load increases with respect to the axial distance D when the vehicle is empty, the attachment device LF at the front end of the leaf spring 610 and the attachment position LR at the rear end of the leaf spring 610. The distance between them increases, and the mounting position LC of the rod 640 rises, pushing the rod 640 upward. Rod 640
Is the displacement of the leaf spring 610 and the shaft 200,
Sensor 650 with the amount of displacement added to the displacement of 300 ground clearance
Since the shaft 652 is rotated, the rotation angle of the shaft 652 increases and the sensitivity also improves. The output voltage of the level sensor changes depending on the position of the arm. Then, as shown in FIG. 9, when the arm is pushed up by the rod above the set value, the CPU determines that it is in the loaded state, and when it is below the set position, it determines that the vehicle is empty.

FIG. 1 is an explanatory view showing the outline of the control device of the present invention. The control device for the starting assist device, which is generally denoted by reference numeral 800, has an air tank 810, and the air in the air tank 810 is the first control valve A 812 and the check valve 8
14, and is sent to the air spring 505 of the starting assistance device 500 via the pipe 820 to increase the ground pressure of the drive shaft 200. The CPU 850, which is a control unit, is activated by the operation switch 860, takes in signals from the level sensor 650 and the vehicle speed 856, and controls the first valve 812 and the second valve B840. First valve 812
Is for controlling the supply of air to the pipe 820, and the second valve 840 is for exhausting the air in the pipe 820. Relief valve 880 provided in the pipe 820
Opens the valve and exhausts air when the pressure in the pipe 820 exceeds a set value.

FIG. 2 is an explanatory view showing another embodiment of the present invention. The control device of this embodiment has a circuit similar to that of the control device of FIG. 1, but a pressure detection switch 870 is provided in the pipe 820 instead of the relief valve, the pressure in the pipe 820 is detected, and this data is sent to the CPU. It is sent to control the pressure in the pipe. The pressure detection switch 870 is provided in the pipe connected to the air spring and detects the pressure inside the air spring. The pressure detection switch outputs when the air in the air spring is below the set value, and stops output when the air exceeds the set value.

FIG. 3 shows the controller 80 of the present invention shown in FIG.
It is a flowchart which shows the control processing of 0. Step S
The process started in 10 detects the vehicle speed in step S11. When the vehicle is stopped, step S12
Then, the process proceeds to and it is detected whether the output signal of the level sensor 600 is in an empty state. When the output of the level sensor is in the empty state, the process proceeds to step S13 and the first valve 81
2 is opened and air is sent to the air spring 505. Step S1
When it is detected that the valve 812 is opened for a certain time in step 4,
In step S15, the valve 812 is closed. This allows
The air spring expands, and the starting assistance device becomes available, and the process ends. When the air pressure of the air spring exceeds the set value, the relief valve 880 opens to adjust the pressure.

When it is detected in step S11 that the vehicle is stopped, the process proceeds to step S12 and step S12.
If the output of the level sensor is in the loaded state in step S,
20 and open the second valve 840 to open the air spring 50
Exhaust the air of 5. When it is detected in step S21 that the valve 840 is opened for a certain period of time, the valve 840 is closed in step S22. As a result, the function of the starting assistance device is deactivated.

FIG. 4 is a flow chart showing another embodiment of the control processing of the control device of the present invention. This control processing is almost the same as the control processing shown in the flowchart of FIG. 3, or after the first valve 812 is closed, step S
When the vehicle speed of the vehicle reaches 20 km / h in step 16, the process proceeds to step S20, the second valve 840 is opened and the air of the air spring 505 is exhausted, which is different from the above process.

FIG. 11 shows a flow chart of the embodiment shown in FIG. After the first valve A is operated in step S13 to start supplying air into the air spring, it is detected in step S14 that the air in the air spring has risen to a predetermined pressure and the output of the pressure detection switch is stopped. Then, the valve is closed in step S15. As a result, the starting assistance device operates. Also, since the air spring does not contain more than the set pressure, even if the drive shaft is pushed up, the pressure inside the air spring does not rise above a certain level, and there is no inconvenience that the diaphragm of the air spring is damaged. . The rest of the control remains the same.

[0027]

As described above, according to the present invention, one of the rear two shafts is used as a drive shaft, and an air spring is provided on this drive shaft to operate the air spring when the vehicle is started or the like so as to generate the ground pressure. In a vehicle equipped with an increasing start assist device, when the vehicle is in an empty state and it is detected that the vehicle has stopped, the start assist device is automatically activated, and the vehicle is in a loaded state. When it is detected that the vehicle has stopped, or when the vehicle exceeds the set vehicle speed, the starting assistance device is deactivated. Therefore, the driver only has to turn on the operation switch, and the driver does not operate when it is not needed, so that the durability of the device is improved. Further, in this device, the air pressure in the pipe is always maintained within the set pressure range, and the durability of the air spring is improved.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a control device according to a first embodiment of the present invention.

FIG. 2 is an explanatory diagram of a control device according to a second embodiment of the present invention.

FIG. 3 is a flowchart of control processing of the control device of the present invention.

FIG. 4 is a flowchart of control processing of the control device of the present invention.

FIG. 5 is a plan view of a vehicle equipped with a starting assistance device.

6 is a side view of FIG.

FIG. 7 is a front view of a drive shaft.

FIG. 8 is an explanatory diagram of an axial load detection device.

FIG. 9 is an explanatory diagram of a level sensor.

FIG. 10 is an explanatory diagram showing an outline of a vehicle having two rear axles.

FIG. 11 is a flowchart of control processing of the control device of the present invention.

[Explanation of symbols]

 1 1A vehicle 10 frame 20 cross beam 60 propeller shaft 70 differential gear case 100 trunnion type suspension 110 trunnion bracket 120 trunnion shaft 130 leaf springs 140, 142, 150, 152 torque rod 200 drive shaft 210 drive shaft housing 300 driven shaft 310 driven shaft housing 500 Starting Auxiliary Device 505 Air Spring 510 Diaphragm 520 Piston 530 Top Plate 540 Compressed Air Supply Port 550 Drive Shaft Side Bracket 560 Frame Side Bracket 570 Mounting Member 600 Axial Load Detection Device (Level Sensor) 800 Control Device 810 Air Tank 812 First Valve 840 Second valve 850 CPU 880 Relief valve 870 Pressure detection switch

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Masaaki Kano 3-25-1 Tonomachi, Kawasaki-ku, Kawasaki, Kanagawa Isuzu Motors Limited Kawasaki Plant

Claims (2)

[Claims] 1. A rear axle having two rear axles, the front axle side of the two rear axles being the drive axle, the other axle being the driven axle, and being mounted on the drive axle to increase the ground pressure of the tire of the axle. In a vehicle equipped with a starting assist device having an air spring, a vehicle speed sensor for detecting a vehicle speed, a level sensor for detecting a load on an axle, an air supply source for supplying compressed air to the air spring, and an air pipe are provided. The control unit includes a first valve that supplies air to the air spring, a second valve that exhausts air from the air spring, a relief valve, and a control unit that controls the first valve and the second valve. When the vehicle is stopped and it is detected that the vehicle is empty, the first valve is opened to supply air to the air spring, so that the vehicle is in the loaded state when the vehicle speed exceeds the set vehicle speed or when the vehicle is stopped. To detect that If well as exhaust air from the air spring by opening the second valve, control device start aid device characterized by air pressure in the piping is opened is when the relief valve and set value or more. 2. The vehicle has two rear axles, one of the two rear axles being the front axle side and the other axle being the driven axle, which is mounted on the drive axle to increase the ground pressure of the tire of the axle. In a vehicle provided with a start assist device having an air spring, a vehicle speed sensor for detecting a vehicle speed, a level sensor for detecting a load on an axle, an air supply source for supplying compressed air to the air spring, and an air pipe are provided. A control unit that includes a first valve that supplies air to the air spring, a second valve that exhausts air from the air spring, a pressure detection switch, and a control unit that controls the first valve and the second valve, Controls the opening and closing of the first valve and the second valve in accordance with a signal from the pressure detection switch to keep the pressure in the air pipe within a set pressure range. apparatus.