JPH10310080A - Trailer traction steering device, and trailer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To facilitate steering operation by providing reverse turn to be achieved even when a trailer is bent in the reverse direction to that in advance turn in reverse turn as the trailer is coupled. SOLUTION: A traction rod 16 which can be expanded/contracted is connected to a coupling member 3 provided on a back part of a tractor 1 to be capable of oscillation. Tires 10L, 10R are installed to be steered relative to an axle 7 of a trailer 6. The tires 10L, 10R are connected to a tie rod 14 through an arm 13. A roller guide 19 is rotatably provided on the traction rod 16, and an arm 30 protruded on the side of the roller guide 19 is connected to a connection 31 extended along the traction rod 16. The tires 10L, 10R are braked by a braking device 34 operated by a motor 36, and as the tractor 1 is moved in a braked condition, the position of a roller 22 is moved forward and backward relative to a rotation center of the roller guide 19. The roller guide 19 is operated to rotate in reverse turn of the tracter 1 in the reverse direction to that in advance turn.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a trailer steering device and a trailer.

[0002]

2. Description of the Related Art In recent years, it has become popular to pull a trailer for carrying equipment necessary for camping and marine sports by a passenger car to a destination. In general, as shown in FIG. 15, a connecting device for connecting a trailer and a towing vehicle has a configuration in which a trailer 82 can rotate left and right with respect to a towing vehicle 81 around a connecting portion (hitch point) 83 in a horizontal plane. Has become.

When the towing vehicle 81 and the trailer 82 can turn left and right around the connecting portion 83 in a horizontal plane, the steering operation when the vehicle is retracted with the trailer 82 connected is troublesome. For example, in the case of retreating to the left, when the steering operation is performed in the same manner as when retreating only with the towing vehicle 81, as shown in FIG. 15, the steering wheels 81a of the towing vehicle 81 are arranged suitable for retreating to the left. However, the trailer 82 is bent at the connecting portion 83 in a direction opposite to the traveling direction of the towing vehicle 81, and the wheels (tires) 82a of the trailer 82 are arranged to be suitable for retreating rightward. If the vehicle continues to retreat in this state, the towing vehicle 81 and the trailer 82 are bent at an acute angle with the connecting portion 83 as a boundary, and a so-called jackknife phenomenon occurs. As a result, the towing vehicle 81 cannot retreat in the target direction.

[0004] In order to avoid the occurrence of the jackknife phenomenon, conventionally, at the time of turning back, first, the steering operation is performed so that the towing vehicle 81 runs in the direction opposite to the target direction, so that the direction of the trailer 82 corresponds to the target direction. Thereafter, the steering operation is performed so that the steered wheels 81a of the towing vehicle 81 are directed to travel in the target direction.

[0005] As a tow steering device for a trailer, there is a trailer 82 provided with a tire 82a of a trailer 82 so as to be steerable, as shown in FIG. In this device, a tire 82a is attached so as to be rotatable about a kingpin 84 with respect to an axle 85. A hitch pin 87 is rotatably attached to the tip of a pulling can 86 fixed so as to extend perpendicular to the axle 85, and an arm 88 is fixed to the hitch pin 87 at the center thereof so as to be integrally rotatable. The arms 89a and 89b fixed to the left and right king pins 84 so as to be integrally rotatable are respectively attached to the rods 9a and 89b.
0a and 90b, the arm 88 is connected to the arm 88.
The tire 82a is steered with the rotation of the wheel 8. In this case, the tire 82 is steered according to the deflection angle, and the turning radius and the inner wheel difference during forward turning can be reduced. As shown in FIG. 15, the deflection angle means an angle θ formed between a straight line L1 extending in the front-rear direction of the towing vehicle 81 through the connecting portion (hitch point) 83 and a straight line L2 extending in the front-rear direction of the trailer 82. I do.

In Japanese Utility Model Laid-Open Publication No. 8-349 or the like, there is provided a connecting device capable of switching a tire of a trailer between a steerable state and a non-steerable state. In such a state, when it is not necessary to make a small turn or a sharp turn, the vehicle travels in a state where steering is impossible.

[0007]

If the case where the deflection angle θ increases in the clockwise direction in FIG. 15 based on 0 ° is defined as “positive”, the towing vehicle 81 moves from the straight running state while the trailer 82 is towed. When moving backward, the deflection angle θ becomes “negative”. Therefore, when the vehicle retreats from the straight traveling state as described above, it is necessary to perform a complicated steering operation in order to avoid the occurrence of the jackknife phenomenon, and the setting of the steering angle at the time of operating the steering wheel differs depending on the retreat speed. Has the problem of requiring skill and skill. When the trailer 82 is connected to an RV (recreational vehicle) or the like, it is difficult to confirm from the driver's seat, and it becomes very difficult to operate the steering wheel.

Further, when the tire 82a of the trailer 82 is configured to be steerable, the turning angle of the towing canister 86 becomes more sensitive than in the case where the tire 82a is fixed to the axle 85, and the vehicle can be further retreated. There is a problem that it becomes difficult.
In the case of the device disclosed in Japanese Utility Model Laid-Open No. 8-349 or the like,
By setting the tires of the trailer (towed side) to be steerable only when the vehicle is traveling forward, an operation similar to that of a fixed axle is performed when the vehicle is moving backward. However, the deflection angle θ was “negative” in each case, and it was not possible to shift from straight running to backward turning without complicated steering operation.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and has as its object that when the trailer is turned backward while the trailer is connected, the deflection angle of the trailer is "negative", that is, the trailing angle is opposite to that during forward turning. It is an object of the present invention to provide a trailer traction steering device and a trailer that can smoothly make a reverse turn even in the state described above and facilitate the steering operation.

[0010]

In order to achieve the above object, according to the first aspect of the present invention, a connecting portion provided at a rear portion of a towing vehicle can be swung right and left via a towing can. A tow steering device for a trailer connected to a tire, the tire being steerably mounted on an axle of the trailer, and an arm rotatably provided on both sides of the axle to steer the tire, A tie rod rotatably connected to the arm and steering the tire through the arm by displacement, and traction that is rotated so that the deflection angle at the time of backward turning is opposite to the deflection angle at the time of forward turning. A swinging member that is turned on the basis of swinging of the can and that is connected to the tie rod to displace the tie rod; and that the swinging member is turned in the reverse direction to the forward turning when the towing vehicle is turned backward. With steering means

According to a second aspect of the present invention, in the first aspect of the present invention, the swinging member has a first end portion rotatably supported at a rear portion of the towing vehicle and the swinging member has a first end. A connecting member extending laterally, and the towbar,
A four-joint link member comprising the connecting member and the link member connecting the towbar is provided so as to be integrally rotatable, and the tie rod is rotatable and its rotation center is the towbar of the link member. The steering unit is configured to be movably supported in a direction intersecting a straight line connecting the connection point with the connection member, and the steering unit moves the rotation center of the tie rod between the link member and the towing turret when the towing vehicle is turned backward. Switching means is provided at a first predetermined position in front of the connection point, and at a position facing the connection point or at a second predetermined position behind the connection point during forward running.

According to a third aspect of the present invention, in the second aspect of the invention, the center of rotation of the rocking member with respect to the link member coincides with a connection point between the link member and the pulling can. A guide groove for guiding a roller provided on the tie rod is formed on the upper side of the guide groove so as to extend in the front-rear direction when the trailer moves straight.

According to a fourth aspect of the present invention, in the second or third aspect of the present invention, the switching arrangement means is arranged so that the center of rotation of the tie rod faces the connection point during forward running. Position.

According to a fifth aspect of the present invention, in the invention according to any one of the second to fourth aspects of the present invention, the switching arrangement means includes an extendable tow tractor and a brake which starts braking when the tow vehicle retreats. And braking means for releasing the braking when the towing can contracts to a predetermined length.

According to a sixth aspect of the present invention, in the invention according to any one of the second to fourth aspects, the switching arrangement means is provided between a retractable retractable pulley and the pullable pulley and the axle. And an actuator provided.

According to a seventh aspect of the present invention, in the first aspect of the present invention, the swing member is arranged in a state where a center of rotation exists forward of the tie rod, and
The steering unit is connected to the tie rod on the rear side, and the steering unit is supported by the connection unit and is turned with the swing of the towing trolley. A first hydraulic cylinder, a first converting means connected to a piston rod of the first hydraulic cylinder, the first converting means converting the rotational power of the rotating member into a reciprocating motion of the piston rod, and a double acting provided on the trailer side. A second hydraulic cylinder of a type, second conversion means for converting the reciprocating motion of the piston rod of the second hydraulic cylinder into the oscillating motion of the oscillating member, and in the middle of a pipeline connecting the two hydraulic cylinders And a solenoid valve for switching the direction of the oil passage between the forward and reverse directions.

According to an eighth aspect of the present invention, in the invention according to any one of the first to eighth aspects, the stopper engages with the arm to regulate the steering angle of the tire within a predetermined range. It has.

A trailer according to a ninth aspect of the present invention includes the traction steering device according to any one of the first to eighth aspects. Therefore, the trailer provided with the towing steering device according to the first aspect of the invention is connected to a connecting portion provided at the rear of the towing vehicle so as to be swingable in the left-right direction via the towing can. Tires mounted to be steerable with respect to the axle of the trailer are steered via arms which are turned by displacement of tie rods. The towbar is rotated so that the deflection angle at the time of reverse turning is opposite to the deflection angle at the time of forward turning. Then, the swing member connected to the tie rod is operated to rotate based on the swing of the pulling pull. The swinging member is rotated by the steering means in a direction reverse to that of the forward turning when the towing vehicle turns backward.

According to a second aspect of the present invention, in the first aspect of the invention, the towing tractor constitutes a part of a four-joint link in which two fixed joints are arranged at a rear portion of the towing vehicle. The deflection angle of the can is opposite between the forward turning and the backward turning. When the link member is relatively rotated with respect to the pulling pull, the swing member is also integrally rotated. The center of rotation of the tie rod with respect to the swing member is moved in a direction intersecting the longitudinal direction of the pulling pulley with the swing of the swing member to steer the tire. The position of the center of rotation of the tie rod with respect to the swing member is located at a position facing the connection point or a second predetermined position behind the connection point during forward traveling. At the time of reverse turning, the rotation center is located at a first predetermined position in front of a connection point between the link member and the pulling can. When the position of the rotation center is the same as the connection point between the link member and the pulling can,
Even if the swinging member is swung, the tie rod is not moved, and the tire is always kept at the straight traveling position. When the position of the rotation center is located behind the connection point between the link member and the pulling can, the tire is steered to a position corresponding to forward turning. When the position of the center of rotation is located forward of the connection point between the link member and the pulling can, the tie rod steers the tire to the opposite phase when the swing member rotates, that is, to a position suitable for backward turning. I do.

According to a third aspect of the present invention, in the second aspect of the present invention, the tie rod is rotatable by the swing member via a roller movable along a guide groove provided in the swing member. Are linked. In a state where the rotation center of the roller is arranged at a position shifted from the rotation center of the swing member,
When the swing member is rotated, the tie rod is displaced via the roller by an amount corresponding to the amount of rotation of the swing member, and the tire is steered.

According to a fourth aspect of the present invention, in the second or third aspect of the present invention, when the vehicle travels forward, the swinging means is configured such that the center of rotation of the roller is set at a connection point between the link member and the pulling can. It is placed at the matching position. In this state, the tire is kept in a straight running state even if the swinging member is turned with the turning of the pulling can. At the time of reverse turning, the same operation as the invention described in claim 2 or 3 is performed.

According to a fifth aspect of the present invention, in any one of the second to fourth aspects of the present invention, the retractable torch is disposed at the extended position when the vehicle is advanced. When the towing vehicle retreats, braking by the braking means is started, and the towing vehicle retracts in the braking state, whereby the towing can contracts. Then, the braking is released when the towing can contracts to the predetermined length, and the rotation center of the tie rod is arranged at the first predetermined position. When the towing vehicle further retreats from that state, the swing member is rotated, the tie rod is displaced, and the tire of the trailer is steered to a position corresponding to the reverse turning.

According to the invention described in claim 6, in the invention described in any one of claims 2 to 4, the retractable tractor is an actuator provided between the tractor and the axle. By operation, it is located at the extended position when traveling forward, and is located at the retracted position when turning backward.

According to a seventh aspect of the present invention, in the first aspect of the present invention, the center of rotation of the swing member is located forward of a tie rod. The turning power of the turning member turned with the swing of the towing can is transmitted to the first hydraulic cylinder provided on the towing vehicle side via the first conversion means. The operating force of the first hydraulic cylinder is transmitted to a second hydraulic cylinder provided on the trailer side via a pipeline, and the reciprocating motion of the piston rod of the second hydraulic cylinder is oscillated by the second conversion means. This is converted into a swinging motion of the moving member. Then, the direction of the hydraulic oil flowing in the pipeline toward the second hydraulic cylinder is changed between forward and reverse by an electromagnetic valve provided in the middle of the pipeline connecting the two hydraulic cylinders. Then, since the towing can is turned (swings) in the opposite direction between the forward turning and the backward turning, as a result, the swinging member is turned in the same direction during the forward turning and the backward turning.

According to an eighth aspect of the present invention, in any one of the first to seventh aspects, the rotation of the arm for steering the tire is restricted by the stopper, and the steering angle of the tire is reduced. It is regulated within a predetermined range.

According to the ninth aspect of the present invention, the same effect as that of the first aspect of the present invention is exhibited.

[0027]

BEST MODE FOR CARRYING OUT THE INVENTION

(First Embodiment) A first embodiment of the present invention will be described below with reference to FIGS. 1 to 4
As shown in FIG. 1, a connecting member 3 is fixed to the rear center of the frame 2 of the towing vehicle 1. The connecting member 3 is provided so as to extend in the front-rear direction of the towing vehicle 1, and has a connecting shaft 4
(Shown in FIG. 2) is fixed so as to extend in the vertical direction. The connecting shaft 4 has a spherical upper end. The connecting member 3 is provided with an arm 5. The arm 5 is fixed so as to be perpendicular to the connecting member 3 in a horizontal state.

The frame of the trailer 6 includes an axle 7 and a beam member 8 welded to the axle 7 so as to extend in the front-rear direction.
a to 8d, and the carrier 9 is fixed above the beam members 8a to 8d. Tires 10L, 10 on both sides of axle 7
R is rotatably supported on the axle 7 via a kingpin 11 and a spindle 12. Each spindle 1
2 is supported by the king pin 11 so as to be integrally rotatable.
Arms 13 are fixed to the spindle 12 so as to be integrally rotatable so as to protrude obliquely inward and forward.
Both arms 13 are rotatably connected to ends of tie rods 14, respectively. In this embodiment, the tie rod 14 is formed in a plate shape.

At the center of the axle 7, a towing frame 15 is provided so as to protrude forward. A towing frame 16 is slidably supported by the towing frame 15. The towing frame 15 and the towing can 16 are both formed in a tubular shape, and the towing frame 15 is inserted into the towing can 16. As shown in FIGS. 2 and 3, a pair of elongated holes 15a are formed on both sides of the towing frame 15 so as to extend in the longitudinal direction.
Are formed. A guide pin 17 is fixed to the pulling can 16 so as to penetrate the elongated hole 15a in a state perpendicular to the longitudinal direction. That is, the towing can 16 is supported by the towing frame 15 so as to be able to slide back and forth within the length of the elongated hole 15a. In this embodiment, a retractable pulling can is constituted by the pulling pulley 16 and the pulling frame 15.

A hitch coupler 18 is provided at the tip of the pulling can 16.
Is attached via a bracket 18a. The hitch coupler 18 is configured to be rotatably connected to an upper portion of the connecting shaft 4 of the towing vehicle 1.

A roller guide 19 as a swinging member is rotatably provided at the rear of the pulling can 16. A support shaft 21 is attached to a bracket 20 fixed to the pulling can 16, and the roller guide 19 is rotatably supported at an upper end of the support shaft 21. The roller guide 19 is formed in an elongated box shape having an open upper part, and extends in the guide groove 1 extending in the longitudinal direction.
9a. A roller 22 is mounted at the center of the tie rod 14 so as to be movable in the guide groove 19a. The roller 22 is formed of, for example, a bearing, and is supported by being fitted and fixed to a lower end of a support shaft 23 fixed to the tie rod 14 so as to extend in the vertical direction.

The roller guide 19 is provided so that the position of the roller 22 can be moved forward and backward on both sides of a support shaft 21 which is a rotation fulcrum of the roller guide 19 by sliding of the traction frame 15. A solenoid 24 constituting a locking means for locking the towing can 16 at a predetermined position is attached to the towing can 16. The solenoid 24 is attached to the pulling can 16 via a bracket 25. As shown in FIGS. 2 and 3, a hole 26 is formed in the pulling can 16 at a position corresponding to the solenoid 24. A hole 27 for positioning the roller guide 19 at the time of reverse travel is formed in the towing frame 15 at a position where the hole 27 can face the hole 26.

The solenoid 24 is provided with a lock pin 28 that can be inserted into the holes 26 and 27. Solenoid 24
When the solenoid 24 is in the excited state, the lock pin 28 is held in a state of being pulled out of the hole 26. When the solenoid 24 is in the demagnetized state, the lock pin 28 is attached to the pulling can 16 at a position corresponding to the hole 26 by a spring (not shown). It is getting energized. When the solenoid 24 is in the demagnetized state, the traction frame 1 is brought into a state where the two holes 26 and 27 face each other.
When the puller 5 and the pulling can 16 are arranged, the lock pin 28 is inserted into the holes 26 and 27. In this state, the guide groove 1
The roller 22 in 9a is located at a first predetermined position in front of the support shaft 21. This state is the state at the time of retreat. (State in FIG. 7) In the demagnetized state of the solenoid 24, when the tip of the towing frame 15 moves to a second predetermined position behind the position facing the hole 26, the tip of the lock pin 28 passes through the hole 26. And held at a position where it can be locked with the tip end surface of the towing frame 15. At this time, the positional relationship between the long hole 15a and the hole 26 is set so that the guide pin 17 is engaged with the front end of the long hole 15a. This state is the state at the time of forward movement. (State of FIG. 1)
In the vicinity of the lock pin 28, a toggle switch 29 is provided as detection means for detecting whether or not the lock pin 28 is at the lock position. The toggle switch 29 is attached to the pulling can 16 via a bracket (not shown). The lever of the toggle switch 29 is connected to a pin protruding from the lock pin 28 via a long hole (both not shown), and is switched between two positions corresponding to the lock position and the unlock position of the lock pin 28. It has become.

An arm 30 as a link member is provided on the roller guide 19 so as to project to the side corresponding to the arm 5 of the towing vehicle 1. The arm 5 and the arm 30 are rotatably connected to ends of a connecting rod 31 as a connecting member. The connecting rod 31, the towing can 16 and the arm 30 constitute a four-node link in which two fixed nodes are arranged at the rear of the towing vehicle 1. The connecting portion between the arm 5 and the connecting rod 31 and the connecting shaft 4 serve as fixed joints. Accordingly, when the pulling can 16 rotates about the connecting shaft 4, the angle between the arm 5 and the pulling can 16 changes, and the roller guide 19 rotates about the supporting shaft 21 via the connecting rod 31 and the arm 30. The two tires 10L and 10R are steered (steered) via the tie rod 14 and the arm 13. The arm 5, the pulling can 16, the arm 30, and the connecting rod 31 are the roller guide 1.
The steering means 9 is configured to rotate the towing vehicle 9 in the reverse direction when the towing vehicle 1 is turned backward and when the tow vehicle 1 is turned forward.

On both sides of the upper part of the axle 7, tires 10L, 10L
Stopper 32 for restricting the steering angle of R within a predetermined range
a and 32b are provided. Stoppers 32a, 32b
Is engaged with the arm 13 when the steering angles of the tires 10L and 10R reach a maximum value within a predetermined range, thereby restricting the steering angle from becoming larger.

A limit switch 33 is mounted on the axle 7 via a bracket (not shown) as a sensor for detecting that the pulling can 16 is located at the retracted position. Further, brake devices 34 are provided at both ends of the axle 7. As the brake device 34, a known device operated by the pulling force of the wire 35 is used. Axle 7
A motor 36 is mounted at a substantially central portion via a bracket (not shown). The motor 36 includes a worm (not shown) and a worm wheel 37 like a wiper motor.
It has. As the motor 36, a DC motor is used.

A pulley 38 is disposed on the axle 7 via a bracket (not shown) so as to be movable in the front-rear direction. A wire 35 is wound around the pulley 38 and is arranged so as to engage with a guide member 39. ing. A lever 41 is fixed to the rotation shaft 40 of the worm wheel 37 so as to be integrally rotatable. The pulley 38 is connected to a lever 41 via a connection bar 42. Then, when the motor 36 rotates forward, the pulley 3 is connected via the lever 41 and the connecting bar 42.
8 is moved in the direction of pulling the wire 35, and the brake device 34 is operated. When the motor 36 rotates in the reverse direction, the pulley 38 is connected to the wire 3 via the lever 41 and the connecting bar 42.
5 is released, and the braking force of the brake device 34 is released.

The brake device 34, together with the roller guide 19, sets the center of rotation of the tie rod 14 at the time of reversing turning of the towing vehicle 1 to a connection point (support shaft 21) between the arm 30 and the towing can 16.
In a first predetermined position further forward, the support shaft 21
And a switching arrangement means for disposing the switching arrangement means at a second predetermined position behind the position opposed to.

Next, an electrical configuration for driving the solenoid 24 and the motor 36 will be described. As shown in FIG. 5, a solenoid 44 is energized by a back lamp switch 43 being closed when a shift lever (not shown) provided on the towing vehicle 1 is arranged at a reverse traveling position, It is connected to a battery (power supply) 45 via a limit switch 33 that detects retreat of the towing can 16. A power supply from the battery 45 and a signal from the back lamp switch 43 are taken out by wiring connected to a connector provided at the rear of the vehicle. As the limit switch 33, a c-contact type switch is used. The relay 44 is in the position indicated by the solid line in FIG. 5 when the shift lever is not in the retracted position. Limit switch 33 has common terminal C
Is connected to the solenoid 24, and the normally closed terminal N
C is connected to the normally open terminal of the relay 44, and the normally open terminal NO is connected to the normally closed terminal of the relay 44. The common terminal of the relay 44 is connected to a power supply 45.

The motor 36 is connected to a power source via a toggle switch 29 which is operated by the movement of the lock pin 28. An interlocking switch composed of a c-contact switch is used as the toggle switch 29, and the lock pin 28 is
In a state where the motor 36 is displaced from the position 6 (unlocked position), as shown by the solid line in FIG. Lock pin 2
In a state where the lock member 8 is disposed at the lock position through the hole 26, each contact is maintained in a connection state indicated by a chain line for driving the motor 36 to rotate in the reverse direction. First contact b of toggle switch 29
Is directly connected to the power supply 45. One of the second contacts a is connected to a normally closed terminal NC and a normally open terminal NO of the limit switch 33 via a limit switch 46 for detecting a state where the brake device 34 has released the brake. The other of the second contacts a is connected to a normally closed terminal NC and a normally open terminal NO of the limit switch 33. As the limit switch 46, a b-contact type switch that is turned off when the brake release state is detected is used.

Next, the operation of the traction steering device configured as described above will be described. The trailer 6 is used in such a manner that the hitch coupler 18 is rotatably attached to the connecting shaft 4 and the first end of the connecting rod 31 is rotatably connected to the arm 5.

At the time of forward movement, as shown in FIG.
6 is pulled out forward, and the roller 22 is located at a second predetermined position behind the support shaft 21 which is a rotation fulcrum of the roller guide 19. In this state, the lock pin 28 is held at a lock position where it comes into contact with the tip of the towing frame 15. Further, the guide pin 17 is provided in the slot 15 as shown in FIG.
a to come into contact with the front end of the towing frame 15.
And the pulling can 16 are fixedly held so as to be relatively immovable.

When the towing vehicle 1 makes a forward left turn in this state, as shown in FIG.
Turn left around the tip of. That is, towing can 1
Numeral 6 is bent toward the turning center with respect to a straight line passing through the hitch point and extending in the front-rear direction of the towing vehicle 1. Then, the connecting rod 3
The arm 30 is pushed rearward by 1 and the arm 30 is rotated counterclockwise about the support shaft 21. Then, the roller guide 19 is also rotated integrally with the arm 30. Since the roller 22 located in the roller guide 19 is located behind the support shaft 21, the roller 22 moves rightward with the tie rod 14 as the roller guide 19 rotates. As a result, the arm 13 connected to the tie rod 14
Is rotated clockwise, and the tires 10L and 10R are also rotated in the same direction and are arranged in a state suitable for a left turn. Therefore, the trailer 6 turns while the inner wheel difference is small during forward turning.

Next, the case where the vehicle turns backward from the straight forward state will be described. The solenoid 24 and the brake device 34 at the time of switching from forward to reverse are operated according to the flowchart of FIG.

When the shift lever is operated to the reverse position in step S1 for the reverse rotation, the relay 44 is turned on (the chain line in FIG. 5). At this time, since the reverse detection limit switch 33 is in the non-operating state, its contact is in a state of connecting the normally closed terminal NC and the common terminal C as shown by a solid line in FIG. ON) (step S2). And lock pin 28
Is moved from the locked position to the unlocked position. When the toggle switch 29 detects that the lock pin 28 is located at the unlock position, that is, the lock pin 28 has been removed (step S3), the contact point is arranged in a state shown by a solid line in FIG. Tire 10 driven forward
L, 10R are braked (step 4).

When the towing vehicle 1 retreats while the brakes are applied to the tires 10L and 10R, the towing can 16 is guided by the long holes 15a and moves rearward along the towing frame 15 with the towing frame 15 stopped. . Then, since the roller guide 19 moves backward together with the pulling can 16, the roller 22 supported by the tie rod 14 on the stopped towing frame 15 relatively moves forward in the guide groove 19 a. As shown in FIG. 7, when the roller guide 19 is disposed at a first predetermined position in front of the support shaft 21,
The limit switch 33 is operated by being pushed by the pulling can 16 (step S5). Then, the limit switch 33
Is switched to a state in which the normally open terminal NO and the common terminal C are connected (the state shown by the chain line in FIG. 5), and the solenoid 24 is demagnetized (turned off) (step S6). In this state, since the hole 26 and the hole 27 of the towing frame 15 face each other, the lock pin 28 is inserted into the holes 26 and 27 by the urging force of the spring, and the towing frame 16 and the towing frame 15 cannot move relative to each other. Locked to.

When the lock pin 28 is located at the lock position (step S7), the toggle switch 29 is switched to the position shown by the chain line in FIG. 5, the motor 36 is driven in reverse (step S8), and the brake is released. You. When the brake is released (step S9), the limit switch 4
The contact of No. 6 is opened, and the driving of the motor 36 is stopped (step S10).

Then, when the towing vehicle 1 further makes a reverse left turn from that state, as shown in FIG. 8, the trailer 6 bends rightward about the hitch point. That is, towing can 16
Is bent to the opposite side to the turning center with respect to a straight line extending in the front-rear direction of the towing vehicle 1 through the hitch point. Then, the arm 30 is pulled forward by the connecting rod 31 and the arm 3
0 is rotated clockwise about the support shaft 21. And
The roller guide 19 is also rotated integrally with the arm 30.
Since the roller 22 located in the guide groove 19 a is located forward of the support shaft 21, the roller 22 moves rightward with the tie rod 14 as the roller guide 19 rotates. As a result, the arm 13 connected to the tie rod 14
Is rotated clockwise, and the tires 10L and 10R are also rotated in the same direction and are arranged in a state suitable for a left turn. Therefore, even if the trailer 6 is bent so that the deflection angle of the towing can 16 is in the opposite direction to that at the time of forward turning, the backward turning is performed smoothly unlike the conventional case.

When turning with a certain turning radius, if the tires 10L and 10R of the trailer 6 are also turned while facing the turning center of the towing vehicle 1, the tires 10L and 10R can turn smoothly without causing side slip. . At the time of backward turning, the towing lever 16 is bent in a direction opposite to that at the time of forward turning, so that the position of the trailer 6 is located outside the forward turning. Therefore, since the tires 10L and 10R are also located outside, smooth turning cannot be performed unless the turning angles of the tires 10L and 10R are set to be larger than those at the time of forward turning. The guide groove 19 a of the roller guide 19 is formed longer on the front side than the support shaft 21, and the distance between the roller 22 and the support shaft 21 at the time of the backward rotation is increased. Therefore, the turning angles of the tires 10L and 10R at the time of reverse turning are larger than at the time of forward turning, and smooth reverse turning is performed.

Further, when the vehicle turns backward, the towing vehicle 1 turns while pressing the trailer 6, so that the deflection angle may become large due to, for example, unevenness of the road surface or external force due to frictional force or the like.
When the deflection angle increases and the turning angles of the tires 10L and 10R increase, the turning radius of the tires 10L and 10R becomes too small than the turning radius of the tire of the towing vehicle 1, and the reverse turning may not be performed smoothly. . However, in this embodiment, the stoppers 32a, 3
2b restricts the rotation of the arm 13, and the tire 10
Since the cut angles of L and 10R cannot be cut beyond a predetermined angle,
Reverse turning is performed smoothly.

Next, the switching from the backward running state to the forward running state will be described. In the reverse running state, the limit switch 33 is in the operating state, and its contact is in a state of connecting the normally open terminal NO and the common terminal C as shown by a chain line in FIG. In this state, when the shift lever is operated to the forward position to turn off the relay 44 (solid line in FIG. 5), the solenoid 24 is excited. Then, the lock pin 28 is moved from the lock position to the unlock position. When the lock pin 28 is located at the unlock position,
The contact of the toggle switch 29 is switched to the position shown by the solid line in FIG. Then, the motor 36 is driven to rotate forward to brake the tires 10L and 10R.

When the towing vehicle 1 moves forward with the brakes applied to the tires 10L and 10R, the towing can 16 is guided by the elongated holes 15a and moves forward along the towing frame 15 with the towing frame 15 stopped. . Then, since the roller guide 19 moves forward together with the pulling can 16, the roller 22 supported by the tie rod 14 on the stopped towing frame 15 relatively moves backward in the guide groove 19 a. When the towing can 16 moves forward and the limit switch 33 is deactivated, the solenoid 24 is demagnetized. Then, the lock pin 28 is urged toward the lock position, but the hole 27 of the towing frame 15 is at a position shifted from the hole 26, so that the lock pin 28 is held in a state pressed against the outer surface of the towing frame 15. You.

When the leading end of the towing frame 15 passes the position facing the hole 26 due to the advance of the towing can 16, the lock pin 28 is arranged at the locking position, and the towing frame 1 is moved.
5 is held in a state of contact with the front end of the fifth embodiment. When the lock pin 28 is located at the lock position, the contact point of the toggle switch 29 is switched to the position shown by the dashed line in FIG. 5, and the motor 36 is driven in reverse to release the brake. When the brake is released, the contact of the limit switch 46 opens, and the driving of the motor 36 is stopped. The roller 22
As shown in FIG. 1, the support shaft 2 is provided in the guide groove 19a.
It is arranged at a second predetermined position ahead of 1 and is in a state suitable for forward running.

This embodiment has the following effects. (A) When the deflection angle during forward turning is "positive", the deflection angle is "negative" during backward turning, that is, the trailer 6 can be smoothly turned backward in a state where the trailer 6 is bent in the opposite direction to that during forward turning. Unlike the conventional case, the reverse turning can be easily performed in the same manner as when the reverse turning is performed only by the towing vehicle 1 without complicated operation of the steering wheel.

(B) The pulling turret 16 which is rotated so that the deflection angle at the time of reverse turning is opposite to the deflection angle at the time of forward turning.
The tires 10L and 10R are steered by displacing the tie rods by a swinging member (roller guide 19) that is rotated by a four-joint link based on the swing of the tie rods. Just by arranging the vehicle behind the center of rotation, the tires 10L and 10R can be automatically steered in a direction suitable for the backward turning by the backward turning of the towing vehicle 1.

(C) Since the roller 22 provided on the tie rod 14 is configured to be slidable along the guide groove 19a formed on the upper side of the swing member (roller guide 19), the roller 22 is turned backward. The arrangement at the first predetermined position suitable for the vehicle and at the second predetermined position suitable for the forward turning is simplified.

(D) The pulling can is configured to be stretchable,
By changing the distance between the axle 7 and the connecting portion of the towing vehicle 1,
The position of the center of rotation of the tie rod 14 can be easily arranged at the first predetermined position suitable for backward turning and the second predetermined position suitable for forward turning.

(E) The extension and retraction of the towing trolley is performed by moving the towing vehicle 1 forward or backward with the brakes applied to the tires 10L and 10R of the trailer 6, so that a dedicated actuator for extending and retracting the towing tractor is used. Becomes unnecessary.

(F) Guide groove 19 of roller guide 19
The length of a is formed so that the front of the support shaft 21 which is the center of rotation is longer than the rear, and the amount of movement of the tie rod 14 with respect to the same amount of rotation of the roller guide 19 during the backward rotation is large, that is, the tire breaking sensitivity. Becomes larger. Therefore,
In the case where the towing vehicle 1 performs the forward turning and the reverse turning with a predetermined turning radius, in any case, the turning can be smoothly performed without the side slip of the tires 10L and 10R.

(G) Stopper 3 provided on support shaft 7
The rotation of the arm 13 is restricted by the 2a and 32b, and the turning angles of the tires 10L and 10R are not cut beyond a predetermined angle, so that the backward turning is smoothly performed.

(Second Embodiment) Next, a second embodiment will be described with reference to FIG. In this embodiment, when the position of the roller 22 of the tie rod 14 with respect to the roller guide 19 is changed between forward turning and backward turning, an actuator for moving the trailer 6 side is used instead of using the movement of the towing vehicle 1. The provision is different from the above embodiment. That is, the tie rod 1
The rotation center of 4 is located at a first predetermined position in front of the connection point (support shaft 21) between the arm 30 and the pulling can 16 and in a second predetermined position behind the position facing the support shaft 21 during forward running. The switching arrangement means for arrangement is constituted by an actuator. The configuration of the four-bar link and the configuration for swinging the tie rod 14 are the same as those in the above-described embodiment. The same portions are denoted by the same reference numerals and description thereof will be omitted.

In this embodiment, an electric cylinder 47 is used as an actuator. Electric cylinder 47
Is configured to operate the rod 48 by changing the forward / reverse rotation of the motor into a reciprocating linear movement of the rod 48. Means for changing the rotation of the motor into the linear movement of the rod 48 include a method using a ball screw and a combination of a pinion and a rack.

The electric cylinder 47 of this embodiment has a built-in motor. The electric cylinder 47 has a base end connected to the traction can 16 via a bracket 49, and a rod 48 connected to the axle 47 via a bracket 50. The electric cylinder 47 is controlled by a control device (not shown) based on the operation of the shift lever. When the shift lever is operated to the forward position, the motor is rotated by a predetermined amount in a direction in which the rod 48 projects (forward rotation direction), and when the shift lever is operated to the reverse position, the rod 48 is retracted (reverse rotation direction). (Direction), the motor is rotated by a predetermined amount.

In this embodiment, when the position of the center of rotation (roller 22) of the tie rod 14 is changed to a position suitable for forward running or reversing turning, the rod 48 of the electric cylinder 47 is extended or retracted by a predetermined amount. This simply completes the operation of simply arranging the roller 22 at the first predetermined position or the second predetermined position.

This embodiment has the effects (a) to (d), (f) and (g) of the above embodiment. Further, unlike the above embodiment, the solenoid 24,
The lock pin 28, the brake device 34, the motor 36 and limit switches for controlling them are not required, and the configuration is simplified.

(Third Embodiment) Next, a third embodiment will be described with reference to FIG. This embodiment is significantly different from the first embodiment in that both tires 10L and 19R are fixed in a straight running state during forward running. Other configurations are the same as those of the first embodiment.

In this embodiment, the center of rotation (support shaft 23) of the tie rod 14 is arranged at a second predetermined position facing the connection point (support shaft 21) between the arm 30 and the pulling can 16 during forward running. It is configured as follows. Specifically, the length of the towing frame 15 and the length of the long hole 15a are changed so that the shaft 23 is opposed to the shaft 21 when the shaft 23 is disposed at the second predetermined position. .

In this embodiment, the same operation and effect as in the first embodiment are exerted during the backward turning. On the other hand, during forward running, the roller guide 19 is
2 is disposed at a position where the center of rotation coincides with the support shaft 21.
In this state, even if the roller guide 19 is rotated along with the rotation of the pulling can 16, the tie rod 14 does not move and the tire is kept straight. Therefore, as shown in FIG. 11, at the time of forward turning, the tires 10L and 10R are fixed to the axle and turned by the same motion as a general unsteerable trailer.

When the tires 10L and 10R are configured to be steerable, and when the vehicle travels straight forward at a high speed, the tires 10L and 10R are left and right even if the towing can 16 slightly swings due to unevenness of the road surface. And the vehicle runs while swaying left and right. However, in this embodiment,
During forward running, the directions of the tires 10L and 10R are maintained in a straight running state, so that the vehicle can run smoothly.

(Fourth Embodiment) Next, a fourth embodiment will be described with reference to FIG. This embodiment is different from the above embodiments in that it is configured to be connectable to an agricultural tractor 51. The difference from the first embodiment is that the arm 30 and the connecting rod 31 are provided symmetrically in a pair,
Is rotatably connected to a link-type drawbar 53 supported on a tractor 51 via a lower link 52. Other configurations are the same as those of the first embodiment. Note that the arm 30 and the connecting rod 31 may be provided on only one side as in the above embodiment. This embodiment has the same effect as the first embodiment.

(Fifth Embodiment) Next, a fifth embodiment will be described with reference to FIG. In this embodiment, the tire 10 is held in a state in which the center of rotation of the swinging member for swinging the tie rod right and left is held at the same position both when moving forward and when moving backward.
The point that L and 10R can be steered (steered) to positions suitable for traveling when moving forward and when moving backward, respectively, is significantly different from the above embodiments. The same members as those of the above-described embodiment are denoted by the same reference numerals, and description thereof is omitted.

The towing can 54 is rotatably connected to a connecting portion 3 provided at the rear of the towing vehicle 1 via a turning shaft 55. A rotating member 56 is supported on the rotating shaft 55 so as to be integrally rotatable. The rotating member 56 is a piston rod 57 of a double-acting first hydraulic cylinder 57 provided on the towing vehicle 1 side.
a. The rotating member 56 is connected to a piston rod 57a via a long hole 56a. Long hole 56a
Constitutes first conversion means for converting the rotational power of the rotating member 56 into reciprocating motion of the piston rod 57a.

The tie rod 58 is divided into two parts.
Each of the tie rods 58 has a swing member 59 arranged in a state where a rotation center (support shaft 60) exists in front of the tie rod 58.
Are rotatably connected to each other. A long hole 59 a is formed in the swing member 59 on the front side of the support shaft 60. A double-acting second hydraulic cylinder 61 is provided on the trailer 6 side. Piston rod 61a of second hydraulic cylinder 61
Is connected to the swinging member 59 through the long hole 59a. The long hole 59a constitutes a second conversion means for converting the rotational power of the swing member 59 into a reciprocating motion of the piston rod 61a.

An electromagnetic switching valve 64 is provided in the middle of the pipelines 62, 63 connecting the two hydraulic cylinders 57, 61. As the electromagnetic switching valve 64, a 4-port 2-position electromagnetic switching valve is used. The electromagnetic switching valve 64 is configured to switch the direction of the oil passage between the forward direction and the reverse direction based on a detection signal of a sensor (not shown) that detects the position of the shift lever 65.

The rotating member 56, the two hydraulic cylinders 57 and 61
The electromagnetic switching valve 64 constitutes steering means for rotating the swinging member 59 in the reverse direction of the towing vehicle 1 in the reverse direction of the forward turning direction.

In this embodiment, the turning power of the turning member 56 which is turned in accordance with the swing of the pulling canister 54 is applied to the towing vehicle 1.
It is transmitted to a first hydraulic cylinder 57 provided on the side through a long hole 56a and a piston rod 57a. The operating force of the first hydraulic cylinder 57 is transmitted to the second hydraulic cylinder 61 provided on the trailer 6 side via the conduits 62 and 63. Piston rod 61 of second hydraulic cylinder 61
The reciprocating motion of “a” is converted into the oscillating motion of the oscillating member 59 via the long hole 59a. Then, the direction of the hydraulic oil flowing in the pipeline toward the second hydraulic cylinder is changed between forward and backward by an electromagnetic switching valve 64 provided in the middle of the pipelines 62 and 63. Therefore, even if the turning direction of the pulling canister 54 is reversed between the forward turning and the backward turning, as a result, the turning direction of the swing member becomes the same direction. Therefore, as in the above-described embodiment, a smooth reverse turning can be performed by operating the steering wheel in the same manner as the reverse turning only of the towing vehicle 1. Further, similarly to the second embodiment, the solenoid 24, the lock pin 28, the brake device 34, the motor 36, and limit switches for controlling them are not required, and the configuration is simplified.

(Sixth Embodiment) Next, a sixth embodiment will be described with reference to FIG. In this embodiment, a structure for transmitting the turning force of the pulling canister 54 to the first hydraulic cylinder 57 and the piston rod 6 of the second hydraulic cylinder 61
The configuration for transmitting the reciprocating motion 1a to the swinging member 59 is different from that of the fifth embodiment.

A pinion 66 is fixed to the rotation shaft 55 so as to be integrally rotatable. A rack 67 that meshes with the pinion 66 is fixed to the piston rod 57a. A pinion 68 is formed integrally with the swinging member 59, and the pinion 6
The center of 8 is rotatably supported by the support shaft 60. A rack 6 meshing with the pinion 68 is provided on the piston rod 61a.
9 is fixed. Accordingly, in this embodiment, when the pulling canister 54 is rotated, the pinion 66 is integrally rotated, and the rotation is transmitted through the rack 67 to the piston rod 57.
a is changed to a linear motion. Further, the linear movement of the piston rod 61a of the second hydraulic cylinder 61
And the rotation of the swinging member 59 via the pinion 68.

Also in this embodiment, the operation of the shift lever switches the electromagnetic switching valve 64 to change the direction of the oil passage between forward turning and reverse turning, and as a result, the swing member 59 is pulled. Regardless of the direction of rotation of the canister 54, the can 54 is rotated in the same direction when turning forward and when turning backward. Therefore, the same effect as in the fifth embodiment is obtained. Further, the transmission of the driving force is performed more efficiently as compared with a configuration in which the driving force is transmitted through the long holes 56a and 59a.

The embodiments are not limited to the above embodiments, but may be embodied as follows. In the second embodiment, the control device that drives and controls the electric cylinder 47 sets the rotation center of the tie rod 14 as the second predetermined position at which the rotation center of the tie rod 14 is disposed during forward traveling, so that the rotation center of the tie rod 14 is It is configured such that it can be selectively disposed at two positions, a predetermined position at the rear and a position facing the support shaft 21. When the vehicle travels straight, it is arranged at a position facing the support shaft 21. In this case, when traveling forward,
Both high-speed straight running and turning running are performed smoothly.

The structure of the second embodiment or the structure described above may be applied to the third or fourth embodiment. The stoppers 32a and 32b may be omitted.

The arm 5 may be directly fixed to the frame 2 of the towing vehicle 1 instead of protruding from the connecting portion 3. Instead of forming the towing can 16 in a cylindrical shape, the towing frame 16 is formed of a square pipe or a pipe having an elliptical cross section, and the towing frame 15 is formed of a pipe or a bar corresponding to the cross sectional shape. In this case, when the towing can 16 expands or contracts or when the connecting rod 31
Is less likely to be twisted during operation.

In the first to third embodiments,
Two arms 30 and connecting rods 31 may be provided symmetrically. The trailer 6 is not limited to two wheels, and may include three or more tires having auxiliary wheels in addition to the tires 10L and 10R as steering wheels.

The technical ideas (inventions) other than those described in the claims, which have been grasped from the above embodiments, will be described below together with their effects. (1) In the invention according to claim 6, an electric cylinder is used for the actuator, and a control device for controlling the driving of the electric cylinder moves the rotation center of the tie rod to the second predetermined position facing the connection point during forward straight traveling. In addition, at the time of forward turning, it is arranged at a predetermined position behind the connection point. in this case,
During forward traveling, both high-speed straight traveling and turning traveling are performed smoothly.

[0085]

As described in detail above, claims 1 to 8 are provided.
According to the invention described in the above, when turning backward with the trailer connected, the deflection angle of the trailer is `` negative '', that is, the reverse turning can be performed smoothly even in the reverse state of the forward turning, and the steering wheel operation is easy. Become.

According to the second aspect of the present invention, the tire is steered by displacing the tie rod by the swinging member which is rotated by the four-bar link based on the swing of the pulling can, and the rotation center of the tie rod is adjusted. By simply arranging the rearward with respect to the center of rotation of the swinging member, the tire can be automatically steered in a direction suitable for the reverse turning by the reverse turning of the towing vehicle.

According to the third aspect of the present invention, the roller is easily arranged at a predetermined position by moving along the guide groove. According to the fourth aspect of the present invention, forward straight traveling is performed smoothly.

According to the fifth aspect of the present invention, the expansion and contraction of the towing can be performed by moving the towing vehicle forward or backward with the brake applied to the tire of the trailer. No actuator is required.

According to the sixth aspect of the present invention, the expansion and contraction of the towing can be easily performed by operating the actuator.
According to the invention described in claim 7, the tire can be steered (steered) to a position suitable for traveling at the time of forward turning and backward turning, respectively, without moving the rotation center of the swing member in the front-rear direction.

According to the eighth aspect of the present invention, since the turning angle of the tire is not cut beyond a predetermined angle due to the presence of the stopper for restricting the rotation of the arm, the reverse turning is smoothly performed. The trailer according to the ninth aspect has the same effect as the invention according to any one of the first to eighth aspects.

[Brief description of the drawings]

FIG. 1 is a schematic plan view of a trailer and a traction steering device according to a first embodiment.

FIG. 2 is a partially cutaway schematic side view of the same.

FIG. 3 is a partially enlarged view of FIG. 2;

FIG. 4 is a partially enlarged partial enlarged view of FIG. 1;

FIG. 5 is a circuit diagram showing an electrical configuration.

FIG. 6 is a schematic plan view showing an operation during forward turning.

FIG. 7 is a schematic plan view of a state in which it is arranged at a backward turning position.

FIG. 8 is a schematic plan view showing an operation at the time of reverse turning.

FIG. 9 is a flowchart in the case of shifting at the time of reverse turning.

FIG. 10 is a partially cutaway schematic side view of the second embodiment.

FIG. 11 is a schematic plan view showing the operation of the third embodiment during forward turning.

FIG. 12 is a schematic plan view of a fourth embodiment.

FIG. 13 is a schematic plan view of the fifth embodiment.

FIG. 14 is a schematic plan view of the sixth embodiment.

FIG. 15 is a schematic plan view of a conventional device.

FIG. 16 is a schematic plan view of another conventional apparatus.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Towing vehicle, 4 ... Connecting shaft as a connection part, 6 ... Trailer, 7 ... Axle, 10L, 10R ... Tire, 13 ... Arm, 14 ... Tie rod, 15 ... Towing frame constituting towing cannon, 16 ... Switching arrangement Tow, constituting means and steering means, 18: hitch coupler, 19: roller guide as swing member, 19a: guide groove, 21: support shaft as connection point, 22: roller, 23: rotation center Axle, 30... An arm as a link member constituting steering means, 31... A connecting rod similarly as a connecting member, 32
a, 32b: stopper, 34: brake device as braking means constituting switching arrangement means, 47: electric cylinder as actuator, 56: rotating member, 56a: elongated hole as first converting means, 57: 1 hydraulic cylinder, 57a ... piston rod, 58 ... tie rod, 59
... Oscillating member, 59a.
0: a spindle as a rotation center, 61: a second hydraulic cylinder, 61a: a piston rod, 62, 63 ... a pipe, 64
... A solenoid switching valve as a solenoid valve.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Hiroshi Matsumoto 2-1-1 Toyota-cho, Kariya-shi, Aichi Prefecture Inside Toyota Industries Corporation (72) Inventor Hiroshi Hattori 5511-11, Wada, Oji, Matsumoto-shi, Matsuno-shi, Nagano Stock Association Inside the company Delica

Claims (9)

[Claims] 1. A tow steering device for a trailer, which is connected to a connecting portion provided at a rear portion of the towing vehicle so as to be able to swing left and right through a towing canister, and which is steered with respect to an axle of the trailer. A tire that is rotatably mounted, an arm rotatably provided on both sides of an axle for steering the tire, and a tire that is rotatably connected to the arm and is displaced to steer the tire through the arm. A tie rod that is rotated based on the swing of a towing rod that is rotated such that the deflection angle during the reverse rotation is opposite to the deflection angle during the forward rotation, and the tie rod is connected to the tie rod. A trailer tow steering apparatus comprising: a swinging member for displacing; and a steering means for rotating the swinging member in a direction reverse to that of a forward turn when the tow vehicle turns backward. 2. The swinging member includes a connecting member having a first end rotatably supported at a rear portion of the towing vehicle and extending on a side of the towing can, the towing can, and the connecting member. And a link member of a four-bar link constituted by a link member that connects the towbar and the towbar. The rotatable tie rod is rotatable. It is configured to be movably supported in a direction that intersects a straight line connecting the connection points of
The steering means sets the center of rotation of the tie rod at a first predetermined position in front of a connection point between the link member and the towing gan when the towing vehicle is turned backward, and at a position facing the connection point when the vehicle is traveling forward. 2. The trailer steering apparatus according to claim 1, further comprising a switching arrangement unit arranged at a second rearward position. 3. The swing member is provided so as to be integrally rotatable with respect to the link member such that the center of rotation thereof coincides with a connection point between the link member and the pulling pulley, and is provided on a tie rod above the swing member. The trailer steering device for a trailer according to claim 2, wherein the guide groove for guiding the provided roller extends in the front-rear direction when the trailer moves straight. 4. The trailer steering apparatus according to claim 2, wherein the switching arrangement means arranges the rotation center of the tie rod at a second predetermined position facing the connection point during forward traveling. 5. The switching arrangement means includes a retractable towbar, and braking means which starts braking when the tow vehicle retreats and releases braking when the towbar contracts to a predetermined length. The traction steering apparatus for a trailer according to any one of claims 2 to 4. 6. The trailer according to claim 2, wherein the switching arrangement means includes a retractable towbar and an actuator provided between the towbar and the axle. Towing steering system. 7. The oscillating member is disposed in a state where a center of rotation is present in front of the tie rod, and is connected to the tie rod at a rear portion thereof, and the steering means is supported by the connecting portion and the towing is provided. A rotating member that is rotated in accordance with swinging of the can, and a double-acting first
A hydraulic cylinder, first conversion means connected to a piston rod of the first hydraulic cylinder, for converting the rotational power of the rotating member into reciprocating motion of the piston rod, and a double-acting type provided on the trailer side. A second hydraulic cylinder, second conversion means for converting the reciprocating motion of the piston rod of the second hydraulic cylinder into the oscillating motion of the oscillating member, The traction steering apparatus for a trailer according to claim 1, further comprising: a solenoid valve provided to switch a direction of an oil passage in a reverse direction between a forward movement and a reverse movement. 8. The trailer steering and steering apparatus according to claim 1, further comprising a stopper that engages with the arm to regulate a steering angle of the tire within a predetermined range. 9. A trailer comprising the trailer steering apparatus according to any one of claims 1 to 8.