JPS6092987A - Two rear-shaft type car - Google Patents

Abstract

PURPOSE:To suppress the change of operation feeling in the course between self- steering and steer-lock by controlling a solenoid valve arranged into the steer- lock cylinder pipe of a rear-wheel shaft according to the input signal of each sensor for car speed, oil pressure, brake pressure, and backward operation. CONSTITUTION:When the speed of a truck shifts from high to low, a solenoid valve 50 is opened and closed by a car-speed sensor 56 under the control of a control unit 54, and steering rear-wheel shafts 33 and 34 are returned to self- steering, and when a steering wheel 17 is turned largely, the oil pressure in a power steering 15 increases, and an oil-pressure sensor 57 transmits a signal into the unit 54. When the unit 54 receives the signals of the sensors 56 and 57, the unit 54 transmits a signal ito the valve 50 similary in case of high speed, and the port is closed and allowed to communicate to a port. Therefore, in the shift from high speed to low speed, or in the reverse shift, the self-steering of the rear-wheel shafts 33 and 34 due to the large operation of the steering wheel 17 is prevented, and the steer-lock state is maintained, and sharp change of steering feeling is suppressed.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a rear two-axle type vehicle in which the rear wheel axle is of a caster type.

In general, the last wheel axle that is not driven by the engine in a rear two-axle vehicle with a heavy load, such as a rear two-axle truck, is configured as a caster type rear axle, which not only reliably supports the load of the truck, but also When the truck turns, it self-steering to reduce the turning radius.

Such a rear two-axle type truck with a caster type rear wheel axle is usually equipped with a steer lock cylinder, and when the truck is traveling at high speed and when reversing,
The caster-type steer rear wheel axle is locked in a neutral state, that is, directed straight ahead, to improve the running stability of the truck when driving at high speeds, and to ensure that the truck backs up safely and securely. It is being structured.

However, when the truck decelerates from high speed to low speed, its steer lock cylinder operates and its steer rear axle goes from steer lock to self steer, especially when When turning in such a self-steering state, it goes without saying that the operating force required on the steering wheel is lighter than in the steer-locked state, and the amount of force required to operate the steering wheel is Since the turning radius of the truck becomes smaller, the feeling of operation tends to change greatly between the steer/lock state and the self-steering state.

The purpose of this invention is to make a caster-type steer rear wheel axle self-operating.
Either the steer state or the steer lock state,
Depending on the driving conditions, the turning radius can be reduced to improve driving stability at high speeds and maneuverability when reversing, and when the steered rear wheel axle transitions from self-steer to steer lock, Another object of the present invention is to provide a rear two-axle vehicle that reduces changes in operating sensation when returning from a steer-locked state to a self-steering state and enables safer driving.

To solve these problems, the rear two-axle type vehicle of the present invention firstly steers the front wheel axle according to the operation of the steering wheel. a caster-type steered rear wheel axle that self-steering according to the turning direction of the wheel, a steer lock cylinder that locks the steered rear wheel axle, and a fluid pressure source that supplies pressurized fluid to the steer lock cylinder; A solenoid valve is installed in the fluid pressure piping that connects the steer lock cylinder and the fluid pressure source, and is electrically connected to the solenoid valve, and is installed in the vehicle speed sensor and the hydraulic system of the power steering. It is composed of an oil pressure sensor, a brake pressure sensor, and an amblifier that controls the opening and closing of the solenoid valve according to input signals from the pack/sensor collar.Furthermore, as other control means for the solenoid valve, It is equipped with a control unit and is configured to highly control the solenoid valve.

Hereinafter, preferred specific examples of the rear two-axle vehicle according to the present invention will be described with reference to the drawings.

Figures 1 and 2 show a rear dual axle vehicle 10 of the present invention embodied as a rear dual axle truck.

Thereafter, the two-axle truck 10 has its front wheel axles 18 and 19 steered by the nozzle steering 15 in response to the steering input, and the rear and front wheel axles 2'9 and 30 are steered by the engine 25 mounted on the truck 10. The last wheel axle 33.34 which is driven and which is then arranged behind the front wheel axle 29.30
is configured as a caster type steer rear wheel axle, and furthermore, depending on the driving conditions of the trunk 10, the steering lock,
The cylinder 39.40 allows its steering rear wheel axle 33.3
4 is configured to be placed in either a self-steering state or a steer-locked state.

That is, after that, the two-axle truck lO has a power steering wheel 15 that steers the front wheel axle 18, 19 according to the operation of the steering wheel 17, and a rear wheel axle 29, 30 that is driven by the engine 25. , a caster-type steer rear wheel axle 33.34 that self-steers according to the turning direction of the trunk 10 by steering the front wheel axle 18, 19, and a steer lock cylinder that locks the steered rear wheel axle 83.34. 39.40, an air tank 48 that supplies compressed air to the steer lock cylinder 39.40, and a pneumatic pipe 49 that connects the steer lock cylinder 39.40 and the air tank 48. A solenoid valve 50 electrically connected to the solenoid valve 50, a vehicle speed sensor 56, a hydraulic sensor 57 provided in the hydraulic system 55 of the e-warf steering 15, a brake pressure sensor 68, and a back sensor. The control unit 54 controls the opening and closing of the electromagnetic valve 50 according to input signals from the electromagnetic valve 69.

The power steering 15 is connected to a front axle beam 120 disposed in front of the chassis frame 11 of the truck 10 through king pins at both ends of the front axle beam 120.
1, respectively, and the front wheels 11111
8, 19 and a pair of knuckles 13°14 with tie rod arms 20.21, a tie rod 22 connecting the ends of the tie rod arms 20.21 with each other;
An integral power steering device 1G rotates a sector shaft (not shown) in response to the operation of the steering wheel 7, and a pitman arm (see FIG. 1) that transmits the movement of the sector shaft to its tie rod 22. (not shown), a drag link 23, a knuckle arm 24, a hydraulic system 55 for the power steering device 16, etc.

'ctD Power steering 15 is applied to existing trucks. Since the configuration is substantially the same as that of the o-war steering, a detailed explanation of the configuration will be omitted.

1, front wheels 60 and 61 are attached to the front wheel axles 18 and 19 of the knuckles 13 and 14, respectively.

Therefore, if the steering wheel 17 is rotated, the power steering device 16 causes the knuckles 13.14 to rotate in the same direction and the front wheel axle 18.19 is steered, so that the front wheel 60.6
1 rudder angle can be changed.

Of course, the e-war steering device 16 has been described as being of an integral type, but it is also possible to use a semi-integral type or a linkage type.

The rear front wheel axle 29.30 is the truck 100 chassis.
It is disposed at the rear of the frame 11 and is driven by an engine 25 mounted on the truck.

Then the front wheel axle 29.30
A transmission 26 is arranged at a rearward position in the frame 11 and rotatably housed in an axle tube 58 equipped with a final reduction gear 59, and is arranged at the rear of the engine 25.
The output shaft of the propeller shaft 31 is connected to the drive shaft of the final reduction gear 59 thereof.

After that, it goes without saying that heavy wheels 62, 63, 64, 65 as double tires are respectively attached to both ends of the front wheel axle 29, 30.

The caster steer rear wheel axle 33.34 then rotates the truck 10 behind the front wheel axle 29.30.
It is configured to self-steering depending on the direction. That is, the steer rear wheel axle 33,34 is
Fixed to knuckle 27.28, that knuckle 27.2
8 is the rear axle beam 3 via the king pin
20 are rotatably attached to both ends.

Furthermore, the knuckle 27.28 is the track 10
It has a knuckle control arm 35, 36 that projects forwardly and a tie rod arm 37, 38 that projects rearwardly.

The ends of the tie rod arms 37, 38 are connected to each other via a tie rod 47 and a ball joint. Furthermore, that tie rod arm 37.38
Preferably, at least one of the ends is pivotally connected to the rear axle beam 32 via a gas-filled damper (not shown) or a damper with a built-in sealing ring (not shown).

Therefore, the pair of knuckles 27.28 is
They are each rotated in the same direction around the king pin by the rods 47, so that their caster steer rear axles 33, 34 are self-teared in the same direction.

The steer lock cylinders 39 and 40 lock the steer rear wheel axles 33 and 34 using compressed air from an air tank 48, which will be described later.
．． 34, it is rotatably arranged on the rear axle beam 32 via a universal joint.

The steer lock cylinder 39, 41J: a cylinder, a diaphragm disposed within the cylinder, and a bushing rod 45, 46 whose one end can be taken in and out of the cylinder and whose other end is connected to the diaphragm.
and a return spring disposed within the cylinder to retract the bushing rod 45,46.

A steer lock cylinder 39 so configured.
40 is rotatably attached via a universal joint to the ends of brackets 41 and 42 fixed at a predetermined distance to the rear axle beam 32, and the bushing rod 45 and 46 ends are connected to the knuckle control.・Arms 35 and 36 are directed toward the ends.

Of course, the universal joint includes a cross guide, and the steer lock cylinder 39.
9.40 is connected to its bracket 41.42.

Additionally, the bushing rod 45, 46 ends of the steer lock cylinder 39.40 are connected to the knuckle control arm 35, 36 ends via sleeves 43, 44.

The sleeve 43,44 is connected to the bushing rod 45.
, 46 is open to form a rod guide bore, and the other end is connected by a ball joint to the knuckle control arm 35, 36 end thereof.

Therefore, if the bushing rod 45.46 of the steer lock cylinder 39.40 is forced out by air pressure, the tip 1 of the bushing rod 45.46 will be at the bottom of the rod guide bore of the sleeve 43.44. Hits the wall and its knuckle control arm 3j,
36 as well as the knuckles 27 and 28 with the king bin in the middle are restricted, in other words, the caster type steer rear wheel shafts 33 and 34 are placed in a steer lock state.

Of course, when the bushing rods 45, 46 of the steer lock cylinder 39°40 are retracted, the tips of the bushing rods 45, 46
It is spaced from the bottom wall of the guide bore to allow reciprocating movement of its sleeve 43.44 relative to its bushing rod 45.46, so that its caster steer rear axle 33
．． 34 is placed in self-steering.

The air tanks 48 are connected to the steer lock cylinders 39, 40 via puncture pressure lines 49, respectively. Of course, the compressed air in the air tank 48 is supplied from an air compressor (not shown) driven by the engine 25 of the truck 1q.

The solenoid valve 50 has a pneumatic line 49 connecting its air tank 48 and its steer lock cylinder 39,40.
It is set in.

The solenoid valve 50 has a tank port 51, a cylinder port 52, and an exhaust port 53, respectively.
A directional control valve which closes its exhaust port 53 by an electrical signal and simultaneously connects its tank port 51 to its cylinder port 52;
1 and simultaneously closes the cylinder port 52 and connects the cylinder port 52 to the exhaust port 53.

The control unit 54 is electrically connected to the solenoid coil of the solenoid valve 50 and includes a vehicle speed sensor 56,
A hydraulic pressure sensor 57 provided in the hydraulic system 55 of the power steering 15 described above, a brake pressure sensor 68 provided in the hydraulic service brake system of the two-axle truck 1O, and a transmission 26 of the truck 10. It controls the opening and closing of the solenoid valve 50 according to the input signal from the back sensor 69 provided in the back sensor 69, and is composed of a sensor, an output circuit, an arithmetic circuit, a memory circuit, a control circuit, and an electrolytic corrosion circuit. There is.

The vehicle speed sensor 56 is disposed in the transmission 26 of the truck 10, similar to existing vehicle speed sensors, and is arranged in the transmission 26 of the truck 10.
It is configured to detect the rotational speed of the output shaft of No. 6, convert the rotational speed into an electrical signal, and send the signal to its control unit 54. Therefore, the vehicle speed sensor 56 is electrically connected to the input circuit of the control unit 54.

The oil pressure sensor 57 is connected to the power steering 15.
Detects the pressure of oil supplied from the oil pump 55 to the power steering device 16, which is arranged on the discharge side of the hydraulic system 5-5, that is, the oil pump, and
It is configured to convert the pressure into an electrical signal and send that signal to its control unit 54. The oil pressure sensor 57 is therefore electrically connected to the input circuit of the control unit 54.

The brake pressure sensor 68 is connected to the last wheel 66.67 mounted on the caster type steer rear wheel axle 33.34.
The hydraulic service brake system is configured to detect the pressure of brake oil in the brake system, convert the pressure into an electrical signal, and send the signal to the control unit 54. has been done. Of course, the brake pressure sensor 68 is electrically connected to the input circuit of the control unit 54.

Further, the backup sensor 69 is provided in the transmission 26 of the truck 10, and detects movement when the change lever is operated in reverse, and detects the change lever.
It is configured to send an electrical signal indicating whether the lever is operated to the reverse side to the control unit 54. Of course, the back sensor 69 is electrically connected to the input circuit of the control unit 54, as are the vehicle speed sensor 56, oil pressure sensor 57, and brake pressure sensor 68 described above.

The rear twin-axle type vehicle 10 of the present invention has the same structure as the existing rear two-axle type truck except as described above, and therefore, a description of these structures will be omitted.

Next, to describe the running of the rear twin-axle truck 100 described above, when the truck 10 is running at low speed, the tank port 51 of the solenoid valve 50 is controlled by a signal from the vehicle speed sensor 56 under the control of the control unit 54 is closed, and cylinder port 52 is communicated with exhaust port 53.

That is, the compressed air within the cylinder chambers of the steer lock cylinders 39, 40 is vented to the atmosphere through their exhaust ports 53, and the bushing rods 45, 46 are retracted inwardly by the return springs.

As a result, reciprocating movement of the sleeve 43.44 relative to the bushing rod 45.46 is permitted, and the caster-type steer rear axle 33.34 is placed in a self-steering condition, allowing for turning when the truck 10 is traveling at low speeds. radius becomes smaller.

At this time, the steer lock cylinder 39°40 is rotatably supported by the rear axle beam 32 via a universal joint, so that the steer rear wheel axle 3a,
In response to the self-steering of a4, the orientation of its steer lock cylinder 39,40 can be changed freely.

Therefore, the steer lock cylinders 39, 40 do not substantially interfere with the self-steering of the steered rear wheel axles 33, 34, and the self-steering is performed extremely smoothly.

Further, when the truck 10 travels at high speed, the exhaust port 53 of the solenoid valve 50 is closed in response to a signal from the vehicle speed sensor 56 under the control of the control unit 54, and the tank port 51 is closed to the cylinder port. 52 will be contacted.

That is, compressed air from the air tank 48 is directed into the cylinder chamber of its steer lock cylinder 39, 40, the diaphragm is moved against the return spring, and the bushing rods 45, 46 are pushed outward, respectively. It will be done.

As a result, the tip of the bushing rod 45,46 is in the sleeve 43,44. It hits the bottom wall of the rod guide der, restricting the reciprocating movement of its sleeve 43.44 relative to its bushing rod 45.46, and placing its caster-type steer rear wheel axle 83.34 in a steer-locked state. Running stability when the truck 10 runs at high speed is improved.

Of course, when the truck 10 moves backward, the transmission 2
When the change lever 6 is operated in reverse, the control unit 54 inputs a signal from the back sensor 69, and the solenoid valve 50 is opened and closed by the output signal from the control unit 54. As in the case of high-speed driving, the caster type steer rear wheel axle: 13.34 is in the steer lock state Kt,
Maneuverability when reversing is stabilized.

Further, when the truck 10 decelerates from high-speed running and transitions to low-speed running, the solenoid valve 50 is opened and closed by a signal from the vehicle speed sensor 56 under the control of the control unit 540, and the caster type steer rear wheel shaft 33
．． 34 is returned to the self-steering state, but when the steering wheel 17 is rotated through a relatively large operating angle in such a state, the oil pressure in the hydraulic system 55 of the nower steering 15 increases, and the oil pressure sensor 5
7 sends an output signal to its control unit "54.

In this way, when the control unit 54 receives respective signals from the vehicle speed sensor 56 and the oil pressure sensor 57, the control unit 54
As in the case of high speed driving, the solenoid valve 50
so that the exhaust port 53 of the solenoid valve 50 is closed and the tank port 51 is communicated with the cylinder port 52.

Therefore, when the trunk 10 decelerates from a high-speed running state and shifts to low-speed running, or when the trunk 10 accelerates from a low-speed running state and shifts to high-speed running, the steering wheel 17 When the wheel is operated relatively largely, the caster-type steer rear wheel axle 33, 34 is not self-steering and is maintained in a steer-locked state, preventing a sudden change in the operating feeling. Ru.

Further, when the truck 10 is running, it is braked by depressing the brake pedal 1, and when the hydraulic pressure of the hydraulic service brake system becomes high, the control unit 54 inputs a signal from the brake pressure sensor 68, and the control unit 54 inputs a signal from the brake pressure sensor 68. The solenoid valve 50 is opened and closed by the output No. 18 from the unit 54, and the caster-type steer rear wheel axle 3:l, 34 is placed in the steer lock state as in the case of high-speed driving described above, and the truck lO is placed in the steer lock state. Safe braking is performed in a stable state.

According to the above invention, there is provided an i9 war steering for steering a front wheel axle, a caster-type steered rear wheel axle, a steer lock cylinder for the steered rear wheel axle, and a fluid pressure source for the cylinder. , is equipped with a solenoid valve provided in a fluid pressure pipe connecting the cylinder and its fluid pressure source, and an amblifier that controls the opening and closing of the solenoid valve, and the amblifier is connected to the vehicle speed sensor and the hydraulic system of the ij quay steering. The solenoid valve is controlled according to input signals from the oil pressure sensor, brake pressure sensor, and back-up sensor installed in the vehicle, so the caster-type steer rear wheel axle is in a self-steering state. Depending on the driving conditions, the turning radius can be reduced, driving stability at high speeds and maneuverability when reversing can be improved.・When transitioning from the steer state to the steer lock state, and when returning from the steer lock state to the self-steering state, the operating feeling will be less likely to change suddenly, and the other controls of the solenoid valve will be less likely to change suddenly. Since it is configured to include a control unit as a means, the solenoid valve can be highly controlled, safety and reliability are increased, and it is extremely practical.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing a rear two-axle vehicle of the present invention embodied as a rear two-axle truck, and FIG. 2 is a structure around a caster type steer rear wheel shaft in the rear two-axle vehicle of the present invention. FIG. 10... Rear two-axle truck, 11... Shitoshi frame, 13.14... Knuckle, 15... Noyawa...
Steering, 17...Steering wheel, 1
8.19...Front wheel axle, 27.28...Knuckle,
33.34...Caster type steer rear wheel axle, 39°40
...Steering lock cylinder, 48...Air tank, 49...Pneumatic piping, 50...Solenoid valve, 54...
... Control unit, 55 ... Hydraulic system, 56
... Vehicle speed sensor, 57 ... Oil pressure sensor, 68 ... Brake pressure sensor, 69 ... Back sensor. Figure 8

Claims (2)

[Claims] (1) Power steering that steers the front wheel axle according to the operation of the steering wheel, a caster type steer rear wheel axle that self-steering according to the turning direction of the vehicle by steering the front wheel axle, and the steering A steer lock cylinder that locks the rear wheel axle, a fluid pressure source that supplies pressurized fluid to the steer lock cylinder, and fluid pressure piping that connects the steer lock cylinder and the fluid pressure source. The sensor is electrically connected to the solenoid valve installed in the vehicle and responds to input signals from the vehicle speed sensor, the hydraulic pressure sensor installed in the power steering hydraulic system, the brake pressure sensor, and the front and back sensors. A rear two-axle vehicle equipped with an ambifier that controls the opening and closing of a solenoid valve. (2) Power steering that steers the front wheel axle according to the operation of the steering wheel, and a caster-type steered rear wheel axle that self-steering according to the turning direction of the vehicle using a plow rudder on the front wheel axle; A steer lock cylinder that locks the steer rear wheel axle, a fluid pressure source that supplies pressurized fluid to the steer lock cylinder, and fluid pressure piping that connects the steer lock cylinder and the fluid pressure source. A solenoid valve is provided, and inputs electrically connected to the solenoid valve include a vehicle speed sensor, an oil pressure sensor provided in the power steering hydraulic system, a brake pressure sensor, and a pack sensor. This is a rear two-axle vehicle equipped with a control unit and metal that controls the opening and closing of the solenoid valve in response to signals.