JPH0522632B2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field This invention configures the rear axle as a steer type, and automatically adjusts the steer rear axle according to the traveling speed.
Relating to a rear two-axle vehicle placed in either a steered or steer-locked state, that is, a straight-ahead state, a steered last axle used in the vehicle, and a steer control device used for the last axle. .

BACKGROUND ART In recent years, large vehicles such as large buses have been configured with three axles, a so-called rear two-axle structure, to reduce the axle load.

In this case, since the last axle is configured as a self-steering type, the self-steering axis has a slow recovery when driving at low and medium speeds, resulting in a delay in the self-steering axis following the steering operation. This caused the running stability to deteriorate.

In addition, in Utility Model Application Publication No. 58-80370, self-
A steering wheel locking device has been disclosed, and in this self-steering wheel locking device, an air chamber is used as an actuator to steer and lock the self-steering wheel in a straight-ahead state when the vehicle is reversing.

Since the air chamber is a brake chamber used in the brake system of a normal vehicle, when the self-steering wheels are steered while the vehicle is moving, so-called forward movement, the self-steer The steering wheel was slow to restore itself, resulting in a decrease in driving stability.

OBJECTIVES AND PROBLEMS OF THE INVENTION An object and problem of the present invention is to speed up the restoration of the steer type last axle when driving at low speeds and medium speeds to avoid a delay in the steer type last axle following the steering operation, and to improve stability,
In addition, the rear twin-axle type ensures a minimum turning radius when turning, improves steering stability, prevents excessive tire wear, and further improves steering stability when driving at high speeds. It is in the provision of vehicles.

Another object and problem of the present invention is to enable the use of a rear two-axle type vehicle to accelerate recovery after steering when the vehicle is running at low speeds and medium speeds, thereby avoiding a delay in following the steering operation; This improves the running stability of the vehicle, and also improves the steering stability of the vehicle by ensuring a minimum turning radius for the vehicle when turning. The purpose is to provide a steer type rear axle which improves steering stability.

Still another object and problem of the present invention is to enable the use of a steer type last axle of a rear two-axle type vehicle to accelerate recovery after steering when the vehicle is running at low speeds or medium speeds, thereby delaying follow-up to steering operation. and improve the running stability of the vehicle.
In addition, steering control improves the steering stability of the vehicle by ensuring a minimum turning radius for the vehicle when turning, and also improves the steering stability of the vehicle when driving at high speeds. The purpose is to provide equipment.

Summary of the 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, and a front axle disposed in front of the chassis frame. a rear axle disposed at the rear of the frame; a rear axle located immediately behind the rear axle at the rear of the chassis frame; a pair of steer rear wheel axles swingably connected to both ends of the rear axle; a pair of push rods arranged correspondingly to the steer rear wheel axle and at both ends of the rearmost axle for regulating the swinging of the steer rear wheel axle;
and a pair of steer controls, each of the pair of steer controls having a sleeve holder for receiving its corresponding push rod, a cylinder at one end for allowing the sleeve holder to be inserted into and removed from the sleeve holder; It is arranged so that it can slide back and forth within the cylinder,
A piston defining a pressure chamber at one end and a spring chamber at the other end in the cylinder to hold the sleeve holder in a double-action manner; a spring force disposed in the spring chamber and acting on the piston; a steer lock spring disposed in its spring chamber to provide its sleeve;
The vehicle comprises a steer type rear axle that is assembled with a centering spring that applies spring force to the holder, and a fluid pressure circuit that supplies pressurized fluid to and discharges pressurized fluid from the pressure chamber of the cylinder of the steer control device. When traveling at low or medium speeds, its steer control device puts its steered rear wheel axle in a self-steering condition, applying restoring force from its centering spring to its steered rear wheel axle, and This system speeds up the restoration of the steered rear wheel axle to avoid delay in the steered rear wheel axle following the steering operation, and
When the vehicle is traveling at high speed, its steering
The control device locks the steering rear wheel axle into a steering lock state, a so-called straight-ahead state.

Further, the steer type rear axle used in the rear two-axle type vehicle of the present invention corresponds to the rear axle, a pair of steer rear wheel axles swingably connected to both ends of the rear axle, and the steer rear wheel axle. a pair of push rods disposed at both ends of the rearmost axle for regulating the rocking of the steer rear wheel axle, and a sleeve holder for receiving the corresponding push rods;
A cylinder that allows the sleeve holder to be inserted and removed at one end; a cylinder that is slidably reciprocated within the cylinder, and that defines a pressure chamber at one end and a spring chamber at the other end; a piston holding the holder in double action, a steer lock spring disposed in its spring chamber to exert a spring force on the piston, and a steer lock spring disposed in its spring chamber to exert a spring force on its sleeve holder; a pair of steer control devices assembled with a centering spring that provides a A restoring force by the centering spring is applied to the steered rear wheel axle in a self-steering state, and the steered rear wheel axle quickly recovers to avoid a delay in the steered rear wheel axle following the steering operation, and When the vehicle is running at high speed, the steering control device allows the steering rear wheel axle to be locked in a steer lock state, so-called straight-ahead state.

Furthermore, the steer control device used in the steer type rear axle of the rear two axle type vehicle of the present invention is arranged to correspond to the steer rear wheel axle that is swingably connected to the end of the rear axle. A push means, which is either a rod and a sleeve holder, or a combination of the rod and sleeve holder, which restricts the rocking of the steer rear wheel axle at one end, and a push means at one end that controls the swinging of the steer rear wheel axle. a cylinder that enables reciprocating movement within the cylinder;
A pressure chamber is defined at one end of the cylinder and a spring chamber is defined at the other end thereof, and a piston is arranged in the spring chamber to provide a spring force to the piston. and a centering spring disposed in the spring chamber to provide a spring force to the pushing means, when the vehicle is running at low and medium speeds. By placing the steered rear wheel axle in a self-steering state and applying the restoring force from its centering spring to the steered rear wheel axle, it is possible to accelerate the restoration of the steered rear wheel axle and avoid a delay in the steered rear wheel axle following the steering operation. Furthermore, when the vehicle is traveling at high speed, the steering rear wheel axle can be locked in a steering lock state, so-called straight-ahead state.

Description of specific examples The following describes the rear two-axle type vehicle of the present invention, the steer type last axle used in the later two-axle type vehicle, and the steer control device used in the steer type last axle of the later two-axle type vehicle. The specified specific example will be explained with reference to the drawings. Figures 1 to 3 show a tenth specific example of the rear two-axle type vehicle of the present invention, which is embodied in a rear two-axle type bus, and of course, after that, The two-axle bus 10 includes a specific example of a steer type rear axle used in a rear two-axle vehicle of the present invention.
11, and specific examples 17 and 18 of the steering control device used for the steer type rear axle of the rear two-axle type vehicle of the present invention.

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. power according to steering input.
The bus 10 is steered by a steering wheel (not shown), and a rear axle (not shown) is located behind the chassis frame and is driven by an engine (not shown) mounted on the bus 10. The rear axle is configured similarly to a normal rear two-axle bus.

Furthermore, the bus 10 is then assembled in a steered manner with the last axle 11 arranged on the chassis frame immediately after the axle, and the bus 10
Depending on the running speed of 0, a pair of steer rear wheel axles 1
3 and 14 are placed in either a self-steering state or a steer-locked state, that is, a straight-ahead state, and a fluid pressure circuit 19 is provided to place the steered rear wheel axles 13, 14 in either of these states. It is composed of

The steer type rear axle 11 is then connected to a rear rear axle 12 disposed at the rear of the chassis frame immediately after the axle, and a pair of steer rear wheel axles 1 swingably connected to both ends of the rear axle 12.
3, 14, a pair of push rods 15, 16 which are arranged correspondingly to the steer rear wheel axles 13, 14 and restrict the swinging of the steer rear wheel axles 13, 14 at both ends of the rearmost axle 12; It is comprised of a pair of steering control devices 17, 18, which are associated with push rods 15, 16, a tie rod 26, and a damper 27.

The steer rear wheel axles 13 and 14 are
0, 21, whose knuckles 20, 21 are swingably connected to both ends of the rearmost axle 12 via king pins, respectively. , 23 and tie rod arm 2
4 and 25, respectively, to facilitate connection of push rods 15 and 16 and tie rods 26.

The push rods 15, 16 are threadedly connected to the housing 29 of a ball joint 28 which is threadedly connected to the knuckle control arms 22, 23, as seen in FIGS. 2 and 3; As shown, it is arranged parallel to the axis of its rearmost axle 12. Of course,
The ball joint 28 screws the ball stud 30 assembled into the housing 29 to the knuckle control arms 22 and 23 via the bearing seats 31 and 32, and screws into the screw hole 33 of the housing 29. 20,21
It is attached to.

The steering control devices 17, 18 are
In terms of arrangement, as can be seen from FIG. 1, a pair of brackets 58,
59, and are combined with push rods 15 and 16 thereof.

The steering control devices 17, 18 are
Regarding the structure, as can be seen from FIGS. 2 and 3, its corresponding push rod 1
a sleeve holder 34 for receiving 5, 16;
A cylinder 35 whose sleeve holder 34 can be put in and taken out at one end, and the cylinder 35
The cylinder 35 is arranged to be reciprocally slidable within the
A piston 36 has a pressure chamber 48 at one end and a spring chamber 49 at the other end, and holds the sleeve holder 34 in a double-action manner. piston 36
Steer lock spring 3 provides spring force to
7 and a centering spring 38 disposed in its spring chamber 49 and applying a spring force to its sleeve holder 34.

The sleeve holder 34 is formed into a sleeve portion 39 by cutting a rod guide bore 40 opened at the tip toward the tip side, and the push rods 15 and 16 can be slid back and forth on the sleeve portion 39. Acceptance and also its rod guide
Connect the bottom wall 41 of the bore 40 to its push rod 1.
I'm using a stopper of 5.16.

Further, the sleeve holder 34 is attached to the nut 43.
A spring seat 42 is secured to the rear end.

Furthermore, the sleeve holder 34 forms a ring stopper 44 on the outer circumferential surface of the sleeve portion 39 at a predetermined position.

The cylinder 35 defines a bore 50 in the end wall 46 of the cylinder body 45.
The sleeve holder 34 can be slid back and forth in the bore 50 in the direction of insertion and removal. Of course, there is a seal ring 5 in the bore 50.
1 and a seal bush 52 are arranged.

Further, the cylinder 35 is connected to the head cover 4.
A cylinder port 55 is formed by welding a pipe connector 54 to the cylinder body 45 on the end wall 46 side thereof.

The cylinder 35 is also attached to brackets 58,59 with bolts 60,61.

The piston 36 is reciprocally slidably disposed within the cylinder 35 and divides the cylinder 35 into a pressure chamber 48 and a spring chamber 49. Of course, the pressure chamber 48 is in communication with the cylinder port 55 and the spring chamber 49 is in communication with the auxiliary spring chamber 53.

Furthermore, the piston 36 has a bore 56 formed on its axis that reciprocably passes through the sleeve holder 34, and a steer lock sleeve 57 is fixed to the bore 56.

Accordingly, the sleeve holder 34 is reciprocatably slidably fitted through the steer lock sleeve 57 and retained on the piston 36.

In addition, the steer lock sleeve 57 is
The base is fitted into the bore 56 of the piston 36 and fixed, and the bore 50 of the cylinder 35 is fitted, and the piston 36 is moved in and out of the cylinder 35 as the piston 36 reciprocates within the cylinder 35. .

That is, the steer lock sleeve 57
The piston 36 is configured to move the sleeve holder 34 in and out of the cylinder 35 depending on the position of the piston 36 within the cylinder 35, and to lock the sleeve holder 34 in the cylinder 35. The sleeve holder 34 is held in a double action manner.

The steer lock spring 37 is the third
As shown, when the compressed air is discharged from the pressure chamber 48 of the cylinder 35, the piston 3
6, push the steer lock sleeve 57 out of the bore 50 of the cylinder 35, and insert the tip of the steer lock sleeve 57 into the ring.
Press against the stopper 44 to lock the sleeve holder 34 to the cylinder 35.

Also, the steer lock spring 37
has its cylinder 35 as shown in FIG.
When compressed air is supplied to the pressure chamber 48 of
Compressed by the piston 36, the steer lock sleeve 57 is drawn into the cylinder 35 with the piston 36, and the sleeve holder 34 is subjected to the spring force of the centering spring 38. While doing so, the cylinder 35 is moved in and out of the cylinder 35.

As such, its centering spring 3
8 exerts a spring force on its sleeve holder 34, the restorability of the steered rear axle 11 is improved, and the self-steering of the steered rear axle becomes very smooth and improved.

That tie rod 26 is Natsukuru 20,2
1, i.e. tie rod arms 24, 25
The steering rear wheel axles 13 and 14, that is, the rear wheels 70 and 71, are connected in between to self-steering in the same direction.

The damper 27 has one end connected to the bracket 62 of the rearmost axle 12 via a pin, and
The other end of the tie rod 26 is connected to the bracket 63 via a pin to alleviate vibrations transmitted from the rearmost wheels 70, 71.

The fluid pressure circuit 19 includes an air tank 64, a compressor (not shown) that is driven by the engine of the bus 10 and supplies compressed air to the air tank 64, and a steering control device that controls the air tank 64. It is configured to include a pneumatic pipe 65 connected to the cylinders 35 of 17 and 18, a solenoid valve 66 disposed in the pneumatic pipe 65, and a control unit (not shown).

The solenoid valve 66 is a directional control valve with a tank port 67, a cylinder port 68 and an exhaust port 69, electrically connecting the solenoid coil to the control unit.

The control unit electrically connects a vehicle speed sensor (not shown) and a back up lamp switch (not shown) and, in response to signals from the vehicle speed sensor and back up lamp switch, The solenoid valve 66 is selectively configured to control the current flowing through the solenoid coil, to connect the tank port 67 to the cylinder port 68, and to connect the cylinder port 68 to the exhaust boat 69. have it done.

The control unit includes, of course, input and output circuits, arithmetic circuits, memory circuits, control circuits,
It consists of a power supply circuit and a power supply circuit.

Next, the traveling of the above-mentioned rear two-wheel bus 10 will be described. Now, if the bus 10 is running at low speed or medium speed, the signal from the vehicle speed sensor will cause
The control unit controls the current flowing through the solenoid coil and the solenoid valve 6.
At 6, the tank port 67 is connected to the cylinder port 68.

As such, when the tank port 67 is connected to the cylinder port 68 in the solenoid valve 66, compressed air is transferred to the pneumatic line 65.
from the air tank 64 to the pressure chamber 48 of the cylinder 35 and the steer lock spring 37 as shown in FIG.
The piston 36 is moved to the right against this.

As such, when the piston 36 is moved to the right within the cylinder 35, the steer lock sleeve 57
6, the steer lock sleeve 57 is retracted into the cylinder 35, and the tip of the steer lock sleeve 57 is pulled into the ring stopper 4 of the sleeve holder 34.
4, the sleeve holder 34 moves away from the cylinder 3 against the centering spring 38 while being guided by the steer lock sleeve 57 supported by the piston 36.
5, the push rods 15, 16 are also allowed to move to the extent that the sleeve holder 34 is moved in and out of the cylinder 35, and as a result, the steer rear wheel axles 13, 14 are moved in and out of the cylinder 35. Centering spring 3
8, in other words under the restoring force provided by its centering spring 38.

Therefore, when the bus 10 turns, the steering rear wheel axle 13,
14's tracking delay was avoided and the turning radius became smaller. In other words, this bus 10 can now turn with the minimum turning radius. And again, that bus 1
When the 0 is returned to the straight-ahead state, its centering
The restoring force by the spring 38 is applied to the steered rear wheel axles 13, 14, and the restoration of the steered rear wheel axles 13, 14 is accelerated, thereby avoiding a delay in the steering rear wheel axles 13, 14 following the steering operation. As a result, the running stability of the bus 10 was improved, that is, such improved running stability was ensured in the bus 10.

Also, if the bus 10 is traveling at high speed,
A signal from the vehicle speed sensor causes the control unit to control the current flowing through the solenoid coil so that the solenoid valve 66 connects the cylinder port 68 to the exhaust port 69.

As such, when the cylinder port 68 of the solenoid valve 66 is connected to the exhaust port 69, the compressed air passes through the steer control side of the pneumatic line 65 to the pressure chamber 48 of the cylinder 35. is emitted into the atmosphere from
As such, when the compressed air in the pressure chamber 48 is vented, the piston 36 is moved leftward into the cylinder 35 by the steer lock spring 37, as shown in FIG. be done.

As such, when the piston 36 is moved to the left within the cylinder 35, the steer lock sleeve 57
6, the steer lock sleeve 57 is pushed out from the cylinder 35, and the tip of the steer lock sleeve 57 hits the ring stopper 4 of the sleeve holder 34.
4, so the sleeve holder 34
is locked in its cylinder 35, and its push rods 15, 16 are also prevented from moving by their sleeve holders 34.

As a result, the steer rear axles 13, 14 are placed in a steer lock condition, and the rear wheels 70, 14 are placed in a steer lock condition.
71 is locked in a straight-ahead state.

Therefore, when the bus 10 turned, the turning became smooth, the running was stabilized, and the operation was accordingly stabilized.

Further, when the bus 10 is retracted, the switching action of the back up lamp switch causes the control unit to control the current flowing through the solenoid coil and the cylinder at the solenoid valve 66. port 6
8 is connected to its exhaust port 69. As a result, the steer rear wheel axles 13, 14 are placed in a steer lock state, as in the case of high-speed running, and the rear wheels 70, 71 are locked in a straight-ahead state.

Therefore, even when the bus 10 turns, the bus 10 turns smoothly.

Although the above-mentioned rear two-wheel bus 10 was described as having a clutch and transmission that are directly operated manually, the rear two-wheel bus 10 is equipped with a clutch and transmission that are servo-operated by a computer. It can also be easily implemented in type vehicles.

In addition, the steering control device 17,1
8 and hydraulic circuit 19 have been described as using pneumatic pressure, but can easily be replaced with one using hydraulic pressure.

Conveniences and Benefits of the Invention As is clear from the specific examples of the invention explained with reference to the drawings, it is clear that the invention will be useful to those who have ordinary knowledge in the technical field to which this invention pertains. The content of the invention is objectively recognized as originating from and incorporating the technical essence of the invention, which is essential to the establishment of the invention and is the nature of the invention in order to accomplish the task of the invention. It can be easily embodied in the manner described.

Conveniences and Benefits of the Invention As understood from the above, the rear two-wheel vehicle of the present invention has a front axle disposed in front of the chassis frame, a rear axle disposed behind the chassis frame, and a rear axle disposed in front of the chassis frame. the last axle located immediately after the axle and behind its chassis frame;
A pair of steered rear wheel axles are swingably connected to both ends of the rearmost axle, and a pair of pushers are arranged correspondingly to the rearmost steered wheel axles to restrict the rocking of the rearmost steered axles. Consisting of a rod and a pair of steering control devices,
a sleeve holder for each of the pair of steer control devices to receive its corresponding push rod; a cylinder for allowing the sleeve holder to be inserted and removed at one end;
a piston which is arranged to be reciprocally slidable in the cylinder, defines a pressure chamber at one end and a spring chamber at the other end in the cylinder, and holds the sleeve holder in a double actionable manner; The steer-type end is assembled with a steer lock spring located in the spring chamber to provide a spring force to the piston, and a centering spring located in the spring chamber to provide a spring force to the sleeve holder. Since it includes an axle and a fluid pressure circuit that supplies pressurized fluid to and discharges pressurized fluid from the pressure chamber of the cylinder of the steering control device, the rear two-axle vehicle of the present invention has the following characteristics: When the steered rear axle is placed in a self-steering condition under the spring force of its centering spring, in other words under the restoring force provided by its centering spring, its steered last axle for the steering operation, i.e. The follow-up delay of the steering rear wheel axle is avoided, the maximum and minimum turning radius of the turn is ensured, the turning becomes smoother, and the steering stability is improved.
Excessive tire wear is prevented, and when returning to straight-ahead driving from a turn, the restoring force from the centering spring is applied to the steered rear wheel axle to hasten the return of the steered rear wheel axle, and the steering response to the steering operation is accelerated. The tracking delay of the steered rear wheel axle is avoided, improving running stability.Furthermore, when driving at high speed, the steered rear wheel axle is in a steer lock state under the spring force of the steer lock spring, that is, when driving straight. The driving stability and turning stability are improved, the steering stability is improved, and it becomes practical.

Further, the steer type rear axle used in the rear two-axle type vehicle of the present invention corresponds to the rear axle, a pair of steer rear wheel axles swingably connected to both ends of the rear axle, and the steer rear wheel axle. a pair of push rods disposed at both ends of the rearmost axle for regulating the rocking of the steer rear wheel axle, and a sleeve holder for receiving the corresponding push rods;
A cylinder that allows the sleeve holder to be inserted and removed at one end; a cylinder that is slidably reciprocated within the cylinder, and that defines a pressure chamber at one end and a spring chamber at the other end; a piston holding the holder in double action, a steer lock spring disposed in its spring chamber providing a spring force on the piston, and a steer lock spring disposed in its spring chamber springing the sleeve holder; and a pair of steer control devices assembled with force-providing centering springs, and the steer control device used in the steered rear axle of the rear twin axle vehicle of this invention includes a pair of steer control devices assembled with force-providing centering springs, and the steer control device used in the steered rear axle of the rear twin axle vehicle of this invention includes Either a rod or a sleeve holder disposed corresponding to a steered rear wheel axle that is swingably connected to the end of the rear axle to restrict the swinging of the steered rear wheel axle, or a push means which is a combination of a rod and a sleeve holder, a cylinder which allows the push means to be put in and taken out at one end, a pressure chamber which is reciprocally slidably disposed within the cylinder and has a pressure chamber at one end within the cylinder; a piston which divides spring chambers at its ends and retains its pushing means in a double actionable manner; a steer lock spring disposed in the spring chamber and imparting a spring force to the piston; and the spring chamber. a centering spring disposed on the rear wheel and applying a spring force to the pushing means;
In the steer control device used for the steer type last axle of the rear two-axle type vehicle of the present invention, when the vehicle is running at low speed or medium speed, the steer rear wheel axle is controlled by the spring force of the centering spring. In other words, under the restoring force provided by its centering spring, it is placed in a self-steering condition, and a follow-up delay of its steered last axle, i.e. its steered rear wheel axle, to the steering operation is avoided; When the vehicle is turned, a minimum turning radius is ensured for the vehicle, smoothing the turn, improving handling stability, preventing excessive tire wear, and ensuring that the vehicle continues straight out of the turn. When returning to the original position, the restoring force from the centering spring is applied to the steered rear wheel axle, speeding up the restoration of the steered rear wheel axle, and avoiding a delay in the steering rear wheel axle following the steering operation, resulting in stable driving. Furthermore, when the vehicle is running at high speed, the steer rear wheel axle is placed in a steer lock state, that is, in a straight-line state under the spring force of the steer lock spring, improving running stability and The turning stability is improved and the steering stability is improved, and as a result, it is very useful and practical for rear two-axle type vehicles.

[Brief explanation of drawings]

FIG. 1 is a partial schematic diagram of a rear two-axle vehicle of the present invention, which is embodied in a rear two-axle bus and includes a steer-type rear axle of the present invention and a steer control device used in the steer-type rear wheel of the present invention; , FIG. 2 is a self-steering state diagram showing the push rod and steer control device partially cut away, and FIG. 3 is a partially cutaway diagram showing the push rod and steer control device. FIG. 6 is a state diagram of the steer lock shown in FIG. 11... Steer type last axle, 12... Last axle, 13, 14... Steer rear wheel axle, 15, 16...
...Push rod, 17,18...Steering control device, 19...Hydraulic pressure circuit, 34...
Sleeve holder, 35...Cylinder, 36...
Piston, 37...Steering lock spring, 38...Centering spring, 48...
Pressure chamber, 49...Spring chamber,
53... Auxiliary spring chamber, 64... Air tank, 65... Pneumatic piping, 66... Solenoid valve.

Claims (1)

[Claims] 1. A front axle disposed in front of the chassis frame; a rear axle disposed behind the chassis frame; and a rear axle disposed behind the chassis frame immediately after the axle. a rearmost axle, a pair of steered rear wheel axles that are swingably connected to both ends of the rearmost axle, and a pair of steered rear wheel axles that are arranged correspondingly to the rearmost steered axle and that restrict the rocking of the steered rear wheelshaft at both ends of the rearmost axle. a push rod, and a pair of steer control devices, each of the pair of steer control devices comprising:
a sleeve holder for receiving its corresponding push rod; a cylinder for allowing the sleeve holder to be inserted and removed at one end; a cylinder for reciprocating sliding movement within the cylinder; having a pressure chamber at one end within the cylinder; a piston defining a spring chamber on each side and holding its sleeve holder in a double-action manner; a steer lock spring disposed in the spring chamber and exerting a spring force on the piston; a steered rear axle assembled with a centering spring disposed in the chamber and applying a spring force to its sleeve holder; and a fluid pressure circuit for supplying and discharging pressurized fluid to and from the pressure chamber of the cylinder of the steer control device. Rear two-axle vehicles including 2. A rearmost axle, a pair of steered rear wheel axles that are swingably connected to both ends of the rearmost axle, and a pair of steered rear wheel axles that are arranged correspondingly to the rearmost steered axle so that the steered rear wheel axles can swing at both ends of the rearmost axle. a pair of restricting push rods; a sleeve holder for receiving the corresponding push rod; a cylinder at one end for allowing the sleeve holder to be inserted and removed; A piston defining a pressure chamber at one end and a spring chamber at the other end and holding the sleeve holder in a double-action manner; a steer disposed in the spring chamber to provide a spring force to the piston; A steerer used in a rear dual axle vehicle comprising a locking spring and a pair of steer controls assembled with a centering spring disposed in the spring chamber and applying a spring force to the sleeve holder. Type last axle. 3 Either a rod or a sleeve holder disposed corresponding to the steered rear wheel axle that is swingably connected to the end of the rearmost axle and that restricts the swinging of the steered rear wheel shaft at the end of the rearmost axle. or a push means that is a combination of the rod and the sleeve holder; a cylinder that allows the push means to be put in and taken out at one end; pressure chamber,
a piston that partitions a spring chamber at the other end and holds the pushing means in a double actionable manner; a steer lock spring that is disposed in the spring chamber and applies a spring force to the piston; - A steering control device for use on a steer type rear axle of a rear dual axle type vehicle, comprising a centering spring disposed in the chamber and applying a spring force to the push means thereof.