JPS61275064A - Rear double-axle type vehicle - Google Patents

Abstract

PURPOSE:To speed up the stability of a self-steering type rearmost axle and improve a driving stability, by feeding a pressure liquid to a stabilizing cylinder from a liquid pressure source when a large size car such a large size bus shifts to a straight running from a circling condition. CONSTITUTION:In a bus 10 is arranged a self-steering rearmost axle 11 at the chassis just at the rear of the rear axle. In order to speed up the stability of the self-steering rearmost axle 11 when the bus shifts to a straight running from a circling condition, a pair of bush rods 22 and 23, a pair of stabilizing cylinders 24 and 25, and a pressure adjusting valve 27 which is installed at a piping 32 to connect a liquid pressure source 26 to the stabilizing cylinders 24 and 25, and driven electrically, are furnished. Moreover, a control unit 28 is arranged to control a current flowing to the pressure adjusting valve 27 according to the signals from a car speed sensor 60, a lateral accelerating speed sensor 61, and a backup live switch 62.

Description

DETAILED DESCRIPTION OF THE INVENTION INDUSTRIAL APPLICATIONS AND RELATED APPLICATIONS The present invention relates to a rear two-axle type vehicle in which the rear axle is configured as a self-steering type.

BACKGROUND ART In recent years, large vehicles such as large buses have been constructed with three axles, in other words, with two rear axles, to reduce the axle load.

In addition, in such large buses, the rear axle in particular has been configured to be self-steering, improving turning characteristics.

However, when the bus transitioned from turning to straight ahead, there was a slight delay in restoring the wheels to the straight direction with respect to the self-steering rear axle.

OBJECTS AND PROBLEMS OF THE INVENTION The objects and problems of the present invention are to reduce the time delay of the last axle of a self-steering type with respect to steering, in other words, to reduce the follow-up delay, and to reduce the minimum turning radius of the vehicle when running at low speeds. Another object of the present invention is to provide a rear two-axle type vehicle that further improves the running stability and handling stability of the vehicle.

Summary of the structural invention related to the object/problem: Contents of the claimed invention In relation to the above-mentioned object/problem, the rear two-axle vehicle of the present invention has a front axle disposed in front of the chassis frame; A rear axle located at the rear of the chassis frame, an idler axle located immediately behind the rear axle at the rear of the chassis frame, and an idler axle rotatably connected to both ends of the idler axle to rotate the wheels. a self-steering rear axle that is capable of supporting a pair of steered rear axles; A restoration operation that receives a pair of push rods that rotate the wheel axle and correspondingly receives the push rods and pushes the push rods in the left and right direction of the chassis frame and in a direction that causes the push rods to move away from each other. a pair of restoring cylinders having sleeve rods and being attached to the idler axle in correspondence with the push rods, and electrically driven and disposed in piping connecting a fluid pressure source to the restoring cylinders; The control unit includes a pressure regulating valve and a control unit that controls the current flowing through the pressure regulating valve according to signals from a vehicle speed sensor and a lateral acceleration sensor, and when the vehicle transitions from a turning state to a straight-ahead state. , which supplies pressurized fluid from the fluid pressure source to the restoring cylinder to hasten the restoring of the self-steer rear axle via the push rod.

Description of Specific Examples Preferred specific examples of the rear two-axle vehicle according to the present invention will be described below with reference to the drawings.

1 to 3 show a rear two-axle type vehicle 10 of the invention of B, which is embodied as a rear two-axle type bus.

The bus 10 has a front axle (not shown) disposed in front of a chassis frame (not shown), and a pair of front wheel axles (not shown) rotatably connected to both ends of the front axle. It is steered by power steering (not shown) in response to steering inputs, and the rear axle (not shown) is steered by its chassis.
It is arranged at the rear of the frame and is driven by an engine (not shown) mounted on the bus 10. As such, the front axle and the rear axle are configured similarly to a normal rear two-axle bus.

Furthermore, the bus 10 then immediately after the axle,
Self-steer type 1 rear axle 11 on the chassis frame
and a pair of push rods 22, 23 in order to hasten the recovery of the self-steering rear axle 11 when the bus 10 transitions from a turning state to a straight-ahead state.
A pair of restoration operation cylinders 24.25, an electrically driven pressure regulating valve 27 disposed in a pipe 32 connecting the fluid pressure source 26 to the restoration operation cylinders 24.25, a vehicle speed sensor 29, and a lateral acceleration sensor 30. , and a control circuit that controls the current flowing through the pressure regulating valve 27 in response to signals from the backup lamp switch 31.
It is equipped with a unit 28.

Immediately behind the self-steer rear axle 11 is an idler axle 12 located at the rear of the chassis frame, and a pair of steer rear axles 13 rotatably connected to both ends of the idler axle 12. .14 and a tie rod 21 rotatably connected between the steer rear wheel axles 13 and 14.

Its steer rear wheel axles 13.14 are respectively knuckled 15.14.
16, whose knuckles 15, 16 are rotatably attached to both ends of the idler axle 12 via king pins, and are rotatably connected to both ends of the idler axle 12. Of course, that knuckle 15.16 is connected to the tie rod arm 17.18 and the restoration arm 19.2.
0 and its tie rod arm 17.1
8, the ends of the tie rod 21 are rotatably connected, and the restoring arm 19, 20 and the push rod 22, 23 are rotatably connected, so that the knuckle 15.16 facilitates the connection of its tie rod 21 and push rod 22.23 by providing its tie rod arm 17.18 and restoring arm 19.20.

The push rod 22.23 is threadedly coupled to the housing of a ball joint 33 which is threadedly coupled to its restoring arm 19,20 as shown in FIGS. 2 and 3 and as shown in FIG. , and is arranged parallel to the axis of the idler axle 12 .

A pair of restoring cylinders 24,25 are made of air cylinders, which in terms of arrangement are fixed to their idler axle 12 and correspond to the brackets 63,64, as can be seen from FIG. It is supported and correspondingly associated with its push rods 22,23.

Its restoring cylinder 24.25 also has a cylinder 34.35 fixed to its bracket 63.64 and a reciprocating slide in its cylinder 34.35, as can be seen from FIGS. 2 and 3 in terms of construction. A piston 40.41 is movably arranged and partitions its cylinder 34.35 into a pressure chamber 36.37 and a spring chamber 38.39; The restoration operation sleeve rod 42, 43 fixed to 41 and its spring
A return spring 44.45 is arranged in the chamber 38.39.

The cylinder 34 , 35 has a rod bore 49 in the rod end wall 47 of the cylinder body 46 and a pipe in the head end wall 48 of the cylinder body 46 .
Connector 50 is welded to form air port 52.

The rod bore 49 consists of a short sleeve 51;
It is aligned with the direction of its corresponding bushing lock F22.23.

The pipe connector 50 also screws the piping 32 into the air tank 56 of the fluid pressure source 26 and connects the cylinder 3 to the air tank 56 of the fluid pressure source 26.
4.35 pressure chambers 36.37 are connected.

The restoration operation sleeve rod 42.43 has a rod guide bore 53 opened at the distal end cut into a sleeve portion 54, and the push rod 22.23 corresponds to the sleeve portion 54. and the bottom wall 5 of the rod guide bore 53.
5 as a stopper for the push rods 22, 23, and in accordance with the movement of the piston 40, 41, the push rods 22, 23 move in the left-right direction of the chassis frame and in the direction of moving the push rods 22, 23 away from each other. It is manufactured in a structure that pushes push rods 22 and 23.

The fluid pressure source 26 includes an air tank 56 and a compressor (not shown) that is driven by the engine of the bus 10 and supplies compressed air to the air tank 56, and is connected to the piping 3.
2 to its restoration operation cylinder 24,25.

The pressure regulating valve 27 is configured in the form of a solenoid valve with a tank boat 57, a cylinder boat 58, and an exhaust port 59, and electrically connects the solenoid coil to its control unit 28. Depending on the vehicle speed and lateral acceleration, the secondary side pressure is changed to speed up or slow down the restoration of the steer rear wheel shafts 13 and 14.

The control unit 28 includes a vehicle speed sensor 60,
The lateral acceleration sensor 61 and the backup lamp switch 62 are electrically connected, and the vehicle speed sensor 60,
In response to signals from the lateral acceleration sensor 61 and the back up lamp switch 62, the solenoid coil controls the current flowing through the solenoid coil, connects the tank port 57 to the cylinder boat 58, and connects the tank port 57 to the cylinder boat 58. - While selectively causing the pressure regulating valve 27 to perform a switching operation to connect the port 58 to the exhaust port 59, the secondary side pressure, that is, the cylinder port side pressure is changed at the same time. .

The control unit 28 is, of course, comprised of input and output circuits, arithmetic circuits, storage circuits, control circuits, power supply circuits, and the like.

Next, to describe the running of the above-mentioned rear twin-axle bus 10, if the bus 10 is currently traveling straight at low speed, the signal from the vehicle speed sensor 60 will cause the control
The unit 28 interrupts the current flowing through its solenoid coil, and at its pressure regulating valve 27 its cylinder port 58 is communicated with its exhaust port 59.

Thus, in the pressure regulating valve 27, when the cylinder port 58 is connected to the exhaust port 59,
The compressed air is discharged from the pressure chamber 36.37 of its cylinder 34.35 to the atmosphere via the line 32, so that when the compressed air in the pressure chamber 36.37 is vented, the piston 40.41 As shown in FIG. 2, the restoring sleeve rod 42. is moved into the cylinder 34.35 by its return spring 44.45 and as the cylinder 34.35 moves.
43 is retracted into the cylinder 34.35 and the tip of its push rod 22.23 is inserted into its restoring sleeve.
Bottom wall 5 of rod guide bore 53 of rod 42.43
5, its push rod 22.23 is guided by its restoring sleeve rod 42.43 and reciprocated within the range permitted by its rod guide bore 53.

As a result, the steered rear wheel axle 13.14 is placed in a self-steering condition and the last wheel 70.71 is self-steering. Of course, the tie rod 21 connected between the tie rod arms 17.
1 self-steering in the same direction.

Then, if the bus 10 turns, its steer rear axle 13,14 will self-steer in phase with the front axle.

Further, if the bus 10 is subsequently to be shifted from the turning state to the straight-ahead state, the control unit 28 is activated by the solenoid according to the signal from the lateral acceleration sensor 61.
The current flowing through the coil is controlled, and at the same time when the tank port 57 is connected to the cylinder port 58 at the pressure regulating valve 27, the secondary side pressure is adjusted to a value corresponding to the lateral acceleration at that time.

In this way, when the pressure regulating valve 27 is operated, the pressure-regulated compressed air passes through the piping 32 to the air tank 5.
6 into the pressure chamber 36.37 of the cylinder 34.35, moving the piston 40, 41 into that cylinder 34.35 against the return spring 44.45, as shown in FIG.

As such, the piston 40.41 is in the cylinder 3
4.35, the restoring sleeve rod 42.43 is pushed out of the cylinder 34.35, accompanied by the piston 40.41, guided in the rod bore 49; Since the bottom wall 55 of the rod guide bore 53 presses against the tip of the push rod 22.23, the push rod 22.23
are pushed by the piston 40.41 via its restoring sleeve rod 42.43 in the left-right direction of its chassis frame and in the direction of pushing its push rods 22.23 away from each other.

As a result, the steer rear wheel axles 13, 14 are quickly restored to the straight-ahead state. In this way, the recovery of the self-steering rear axle 11 is accelerated and the bus 10 is smoothly transitioned from a turning condition to a straight-ahead condition.

Also, if the bus 10 is running at high speed, the control unit 28 controls the current flowing through the solenoid coil based on the signal from the vehicle speed sensor 60, and the pressure regulating valve 27 controls the current flowing through the tank port. 57 to its cylinder port 58.

With its pressure regulating valve 27 so operated, compressed air flows from the air tank 56 via the line 32 to the pressure chamber 36.37 of the cylinder 34.35 and returns to the pressure chamber 36.37 of the cylinder 34.35, as shown in FIG. - Move the piston 40.41 into its cylinder 34.35 against the spring 44.45.

Therefore, in the same way as when the bus 10 is transferred from the turning state to the straight-ahead state, the push rod 22.
23 in the left-right direction of its chassis frame by means of its piston 40.41 via its restoring sleeve rod 42.43 and its push rod 22.2.
3 are pushed away from each other.

As a result, its steer rear wheel axle 13.14 is placed in a steer lock condition, and the rearmost wheel 70.71 is locked in a straight-ahead condition.

Therefore, when the bus 10 turns, the turning becomes smooth, the running is stabilized, and the handling is accordingly stabilized.

Additionally, if the bus 10 is retracted, the switching action of the back up lamp switch 62 causes the control unit 28 to control the current flowing in the solenoid coil and in the pressure regulating valve 27. Tank boat 57 is connected to cylinder port 58. As a result, the steered rear wheel axle 13.14 is placed in a steer lock state, as in the case of high-speed travel, and the last wheel 70.71 is locked in a straight-ahead state.

Therefore, even when the bus 10 is turned, the bus 10 is turned smoothly.

In the bus 10 described above, the restoring operation cylinders 24, 25, the fluid pressure source 26, the pressure regulating valve 27, etc. were described as using pneumatic pressure, but they can be easily replaced with those using hydraulic pressure.

Advantages and Benefits of the Invention As mentioned above, compared to the rear dual axle vehicles with self-steering rear axles that have been proposed and used, the rear dual axle vehicle of the present invention has the following advantages: A pair of push rods are disposed near opposite ends of the idler axle in correspondence with the steer rear axle to rotate the steer rear axle about the ends of the idler axle, and a pair of restoring cylinders rotate the steer rear axle around the ends of the idler axle. a restoring sleeve rod correspondingly receiving and pushing the push rod in the left-right direction of the chassis frame and in a direction causing the push rods to move away from each other; A pressure regulating valve mounted on the idler axle and electrically driven is arranged to connect a fluid pressure source to the restoring cylinder, and a control unit is arranged to connect a fluid pressure source to the restoring cylinder, and a control unit is arranged to connect the hydraulic pressure control valve to the restoring cylinder. Since the current flowing through the pressure regulating valve is controlled, in the rear two-axle vehicle of the present invention, when the vehicle transitions from a turning state to a straight-ahead state, the steering rear wheel axle is quickly returned to a straight-ahead state by the restoring operation cylinder. the self-steer last axle is restored, thus hastening the restoration of the self-steer last axle, reducing the time lag of the self-steer last axle relative to steering, i.e., the following delay, and also reducing the minimum of the vehicle at low speeds. The turning radius can be reduced, and the running stability and handling stability of the vehicle are improved, making it more practical.

As for the relationship between the invention and the specific examples, from the specific examples of the present invention described with reference to the drawings, various design modifications will be apparent to those who have ordinary knowledge in the technical field to which this invention pertains. Modifications and alterations may be easily made, and furthermore, the content of this invention may be substantially the same as that invention in that it satisfies essentially the same problem as that invention and achieves the same effect as that invention. It would be easily replaced by an identical aspect.

[Brief explanation of drawings]

Fig. 1 is a partial schematic diagram of a rear two-axle type vehicle of the present invention, which is embodied in a rear two-axle type bus, and Fig. 2 shows a push rod-restoring operation cylinder that is used when the vehicle is running at low speed. FIG. 3 is a self-steering state diagram shown in partial cross section, and FIG. 3 is a restoring state diagram showing the push rod-restoring operation cylinder in partial cross section when the vehicle transitions from turning to straight running. . 11. Self-steering rear axle, 22.23 Bushing rod, 24.25 Restoration operation cylinder, 26
-Fluid pressure source, 27...Pressure regulating valve, 28...Control unit l. Patent Applicant Nissho Jidosha Kogyo Co., Ltd. Agent Patent Attorney Yama 1) Osamu Yamasa I-Yu

Claims (1)

[Claims] A front axle disposed in front of a chassis frame, a rear axle disposed behind the chassis frame, and an idler axle disposed behind the chassis frame immediately after the axle. a self-steering rear axle consisting of an axle and a pair of steered rear axles rotatably connected to both ends of the idler axle and rotatably supporting the wheels; a pair of push rods disposed proximate the ends of the idler axle for rotating the steer rear wheel axle about the ends of the idler axle; a pair of restoring cylinders mounted on the idler axle corresponding to the push rods and having a restoring sleeve rod for pushing the push rods away from each other; a control unit that controls the current flowing through the pressure regulating valve in response to signals from the vehicle speed sensor and the lateral acceleration sensor; Rear two-axle vehicles including