JPH08118935A - Controller for start assisting apparatus - Google Patents

Abstract

PURPOSE: To reduce the ground contact pressure to a normal value for preventing a vehicle from slipping due to air pressure reduction after parking when an engine key is turned off in a vehicle equipped with a start assisting apparatus for increasing the ground contact pressure of a drive shaft. CONSTITUTION: A driven shaft of two rear shafts is equipped with a start assisting apparatus using a pneumatic springs 505 to increase the ground contact pressure of the drive shaft 200 and the traction in the start or the like of a vehicle. A controller 800 opens an exhaust valve B830 when the controller detects an engine key turned off, and exhausts air in the pneumatic spring 50 so that a parking brake force shared by the drive shaft tire is returned to a steady state.

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. 9 is an explanatory view showing an outline of a vehicle having two rear axles. A large vehicle generally designated by reference numeral 1 has a front axle 21 at a front portion of a frame 10 and a front tire. 21a is supported. The rear part has two axles 31 and 32 and supports tires 31a and 32a, respectively. Rear two axes 31, 32
Is supported by the frame 10 via the suspension 40, and the 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 cannot 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. By adopting this device, slope climbing performance is improved and slope braking performance is also improved.

As shown in FIG. 10, a parking brake 65 of a vehicle 1 of this type has a structure in which a propeller shaft 60 that transmits a driving force to a rear drive shaft 31 equipped with a starting assist device is mechanically locked. Have. Therefore, the performance of the parking brake is also improved by increasing the ground pressure of the locked drive shaft by operating the starting assist device.

[0006] In addition, the vehicle may be parked on a slope or the like with the gears of the transmission in a forward low speed position on an uphill or a reverse speed position on a downhill. Also in this case, the grounding pressure is increased and the parking performance is improved by operating the starting assist device. That is, when the vehicle 1 approaches the uphill road SL from the flat road L and the driver depresses the brake pedal, the service brake hydraulically operates the brakes of all the wheels and stops. When the parking brake 65 is pulled in this state or the gear is put in and the brake pedal is released in this state, the braking force of the vehicle 1 is taken up only by the drive shaft tire 31a. When the vehicle stops, the start assist device operates in preparation for the next start. However, when the start assist device is operating while the parking brake is applied or the gear is engaged, the ground contact pressure of the drive shaft tire 31a is increasing, and in this state parking is also possible on this slope SL. May be.

However, when the driver pulls the parking brake or puts the gear into the engine to turn off the engine key to stop the engine, the air compressor also stops. At this time, there is no problem if sufficient air is stored in the air tank and the air spring of the start auxiliary device is operating normally, but after the driver descends, the air pressure of the air spring drops for some reason. Then, the ground contact pressure of the axle is lowered, and the sufficient frictional force of the parking brake cannot be obtained, so that the vehicle slips down. Therefore, when the engine key is turned off, the air spring is exhausted and the ground pressure of the drive shaft tires is made equal to that of a normal vehicle, so that the vehicle can assist in starting the vehicle on a slope where a normal vehicle cannot park. Do not allow the device to operate and park. The present invention provides a control device for a starting assist device that achieves the above-mentioned object.

[0008]

SUMMARY OF THE INVENTION A control device of the present invention is a vehicle equipped with a vehicle start assisting device having an air spring on the drive shaft of the rear two shafts, and includes an engine key switch and a vehicle speed sensor. 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 air for the air spring. A second valve for exhausting air and a control means for controlling the first valve and the second valve are provided.

[0009]

When the control means detects that the engine key has been turned off, the control means opens the second valve to exhaust the air from the air spring.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIGS. 4 to 6 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 mounted 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 drive shaft housing 210 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 via 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 is started which requires a large propulsive force, the starting assisting device is operated to achieve a smooth start. 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. 7, 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 through 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 spring 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 the suspension of this kind, the sensitivity of detecting the axial load 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.

FIG. 1 is an explanatory view showing the outline of the control device of the present invention. The control device for the start assisting device, which is generally denoted by reference numeral 800, has an air tank 810, and the air in the air tank 810 includes a first magnetic valve 820 (valve A), a second magnetic valve 830 (valve B),
Piping 840, first pressure switch 8 for low pressure detection
50, sent to the air spring 505 of the starting assistance device 500 via the second pressure switch 852 for high pressure detection,
The ground pressure of the drive shaft 200 is increased. The CPU 860 that is a control unit includes a key switch 862, an operation switch 872, an operation lamp 870, a speed sensor 868, a level sensor 600 that is an axial load sensor, a first pressure switch 850 for low pressure detection, and a second pressure switch 850 for high voltage detection. It is connected to the pressure switch 852 and controls the first magnetic valve 820 and the second magnetic valve 830. The first magnetic valve 820 has a function of supplying air in the air tank 810 to the pipe 840 by opening the valve, and the second magnetic valve 830 having a function of exhausting air in the pipe 840 by opening the valve. .

FIG. 2 shows the operation of the pressure detection switch.
The low pressure detection switch is a switch for detecting whether or not the air in the air spring has been sufficiently discharged at the time of discharging the air, and is turned on when the set pressure is aKg / cm ² or less as shown in the figure.

The high-pressure detection switch is a switch for detecting whether or not air is sufficiently supplied into the air spring during air supply, and is turned on when the set pressure is bKg / cm ² or more as shown in the figure.
To do. Below the set pressure a, the ground contact pressure of the tire of the drive shaft is the same as that of a vehicle not equipped with a start assist device. or,
When the pressure is equal to or higher than the set pressure b, the ground pressure of the tire on the drive shaft increases, and the propulsive force at the time of starting also increases.

<< Operation of Start Assist Device >> FIG. 3 is a flowchart showing the control processing of the control device 800 of the present invention. Starting from step S11, the process proceeds to step S14 according to the flow chart, and if the vehicle speed is 20 Km / h or less in step S14, the process proceeds to step S15 in order to operate the starting auxiliary device. In step S15, the air pressure of the air spring is checked. If the high pressure detection switch is OFF in step S15, that is, if the air is not sufficiently supplied, the process proceeds to step S16. If the supply valve is not open, the process proceeds to step S17, the supply valve is opened, and the air to the air spring is opened. Is started and the process returns to step S11. If the supply valve has already been opened in step S16, the process directly returns to step S11.

After returning to step S11, step S
The same flow is repeated until the high pressure detection switch is turned on at 15, and air is continuously supplied. If enough air enters the air spring and the high pressure detection switch is turned on in step S15,
Proceeding from step S40 to step S41, the valve is closed, and the operation of the starting auxiliary device is completed.

<< Air Ejection When Starting Auxiliary Device Is Not Required >> If the key switch is ON in step S11, the process proceeds to step S12. If the operation switch is OFF in step S12, the process proceeds to step S30. If the operation switch is ON in step S12, the process proceeds to step S13 and step S13.
If the axle load sensor detects the loaded state in 13, the process proceeds to step S30. If the axle load sensor is empty in step S13, the process proceeds to step S14, and if the vehicle speed is 20 km / h or more in step S14, the process proceeds to step S30. The reason for proceeding to step S30 is to discharge air.

In step S30, the low voltage detection switch is turned off.
F, that is, if air is present in the air spring, step S
Go to 31 and step S if the discharge valve is not open
At 32, the discharge valve is opened to start bleeding the air spring, and the process returns to step S11. If the discharge valve has already been opened in step S31, the process directly returns to step S11.

After returning to step S11, step S
The same flow is repeated until the low pressure detection switch is turned on at 30, and air is continuously discharged. If the air of the air spring is sufficiently released and the low pressure detection switch is turned on in step S30,
From step S50 to step S51, the valve is closed. As described above, the air is released when the starting assist device is not needed.

<< Air Ejection when Key Switch is Off >> If the key switch is off in step S11, the process proceeds to step S20. If the exhaust valve is not open, the exhaust valve is opened in step S21, and the air spring is opened. Begins to be discharged, and the process proceeds to step S22. Step S2
If it is 0 and the discharge valve is already open, the process directly proceeds to step S22.

In step S22, the state of the key switch is checked again. This is to check whether the key is turned on while discharging the air. Step S22
If it is confirmed that the key is turned off in step S23, the process proceeds to step S23. If a predetermined time has passed after the key was turned off, the valve is closed in step S24 and the process is terminated. The predetermined time is the time until the air completely escapes from the air spring, and is stored in the CPU in advance. As described above, when the key is turned off, the air is released to prevent the parking by operating the starting assist device.

[0035]

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 a starting assist device for increasing the number, when the vehicle is stopped and the driver turns off the engine key, the vehicle is equipped with a control device that detects this signal and exhausts the air of the air spring. When the engine key is turned off, the start assist device is disabled so that the parking brake force received by the drive shaft tires is equal to that of a vehicle without a start assist device, and measures such as vehicle slip are reliably implemented. It is the one to be confused.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a control device of the present invention.

FIG. 2 is an explanatory view showing the operation of a pressure detection switch.

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

FIG. 4 is a plan view of a vehicle equipped with a starting assistance device.

5 is a side view of FIG.

FIG. 6 is a front view of a drive shaft.

FIG. 7 is an explanatory diagram of an axial load detection device.

FIG. 8 is an explanatory diagram of a level sensor.

FIG. 9 is an explanatory diagram showing an outline of a vehicle having two rear axles.

FIG. 10 is an explanatory diagram showing parking on a slope.

[Explanation of symbols]

 1 1A Vehicle 10 Frame 20 Cross Beam 60 Propeller Shaft 65 Parking Brake 70 Differential Gear Case 100 Trunnion Type Suspension 110 Trunnion Bracket 120 Trunnion Shaft 130 Leaf Spring 140, 142, 150, 152 Torque Rod 200 Drive Shaft 210 Drive Shaft Housing 300 Driven Shaft 310 Driven shaft housing 500 Start assist 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 650 Axial load detection device (level sensor) 800 Control device 810 Air tank 820 No. 1st valve 830 2nd valve 860 CPU 862 Key switch 868 Speed sensor 872 Dynamic switch

Claims (1)

[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 provided with a start assist device having an air spring, an engine key switch, 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 source. A first valve provided in the pipe for supplying air to the air spring, a second valve for exhausting the air of the air spring, and a control unit for controlling the first valve and the second valve, The unit is a control device for a starting assistance device, which opens a second valve to exhaust air from an air spring when detecting that the vehicle is stopped and the engine key is turned off.