JPH0761365A - Hydraulic steering device for trailer - Google Patents

Abstract

PURPOSE:To further reduce the size of the rotation displacement transmitting device of a tractor by a method wherein a king pin to transmit rotation of a tractor is arranged in a protruding state to the lower front part of a trailer and coupled to a gear, rotated togetherwith a king pin, through a timing belt and a gear to operate a hydraulic mechanism through a hydraulic control valve is provided. CONSTITUTION:A gear 7 located above a downward protruding king pin 6 and rotated togetherwith the king pin 6 and a gear 8 coupled to the gear 7 through a timing belt 9 are disposed to the front F of a trailer 1. The king pin 6 and a rotary plate 24 are rotated according to rotation of a tractor 2 and the gear 8 is rotated by the gear 7 through the timing belt 9. According to a rotation amount thereof, an oil pressure control device 10 is operated and an oil pressure from a hydraulic drive source 23 arranged to the tractor 2 is fed to a hydraulic mechanism 5 through oil pressure pipings 22 and 21, a flow rate control valves 11, and an oil pressure piping 20. The oil pressure is fed with a pressure to hydraulic cylinders 12 and 13 to rotate the rear wheels 3 and 4 of a trailer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic steering device for a trailer, and more specifically, to the rotation of a tractor by displacing an axle of a rear wheel of the trailer by a hydraulic mechanism in response to rotation of the tractor towing the trailer during traveling. The present invention also relates to a trailer hydraulic steering device that rotates a rear wheel of a trailer.

[0002]

2. Description of the Related Art As a mechanism for displacing the axles of the rear wheels of a trailer in response to the rotation of a tractor while it is traveling, for example, as disclosed in Japanese Utility Model Laid-Open No. 3-52285, the front of the trailer 1 shown in FIG. A pair of left and right hydraulic cylinders that operate according to the rotational displacement of the tractor are attached to the section F, and the system that steers the rear wheels of the trailer is used by operating the hydraulic cylinders attached to the rear of the trailer via these hydraulic cylinders. However, in this method, since it is necessary to dispose a hydraulic cylinder between the upper surface 26 and the lower surface 27 of the luggage carrier 25 at the front portion F of the trailer, the distance h between the upper surface 26 and the lower surface 27 of the luggage carrier is reduced. As a result, the ground height H + h of the upper surface of the loading platform becomes high, which hinders the loading work on the loading platform 25 and affects the stability of the trailer while traveling. Was Tsu.

In order to solve this difficulty, the inventors of the present invention previously proposed to reduce the size of the device for transmitting the rotational displacement of the tractor, which is disposed between the upper surface and the lower surface of the loading platform at the front of the trailer. As shown in FIG. 5, below the front part F of the trailer 2
7, a bevel gear 28 that horizontally rotates together with the king pin 6 is attached to the upper portion of the king pin 6 that engages with the coupler portion of the tractor and transmits the rotational displacement of the tractor. Another bevel gear 29 that turns to
Has proposed a steering device for a trailer in which a hydraulic mechanism for activating the axles of the rear wheels 3, 4 of the trailer is operated via the hydraulic control valve 10. (Japanese Patent Application No. 5-47531) However, even in this device, there is a problem that the mounting position of the bevel gears must be precisely positioned in order to accurately mesh the bevel gears 28 and 29 with each other. Since the control valve 10 is housed between the loading platforms, the thickness h between the loading platforms does not become sufficiently thin.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above problems in the conventional steering device for the rear wheels of the trailer, and its purpose is to provide an upper surface and a lower surface of the front portion of the trailer. A hydraulic steering device for a trailer that does not require precise positioning of the mounting position, like a bevel gear, by further reducing the size of the device for transmitting the rotational displacement of the tractor, which reduces the thickness between the loading platforms. To provide.

[0005]

To achieve the above object, a hydraulic steering system for a trailer according to the present invention comprises:
The rotational displacement of the tractor pulling the trailer during running is
In the hydraulic steering device of the trailer, which is transmitted to the axle of the rear wheel of the trailer through the hydraulic mechanism provided with the trailer and rotates the rear wheel of the trailer in accordance with the rotation of the tractor, the tractor is located below the front of the trailer. A king pin that engages with the coupler portion is provided in a protruding manner, and a gear that rotates together with the king pin is provided above the king pin, and a gear that is connected to the gear by a timing belt and rotates to operate the hydraulic mechanism via a hydraulic control valve. Is provided in the configuration.

The present invention is an apparatus for transmitting a rotational displacement of a tractor, which is arranged between the loading platforms above the kingpin in a known structure in which a kingpin engaging with the coupler of the tractor is projected from the lower surface of the front part of the trailer. It is characterized by adopting a combination of a gear and a timing belt. As the hydraulic mechanism used in the present invention for transmitting the rotational displacement of the tractor during traveling to the axle of the rear wheel of the trailer, the known mechanism used in the above-mentioned prior art is applied.

[0007]

In the present invention, since the device for transmitting the rotational displacement of the tractor is composed of a combination of two gears and a timing belt connecting the gears, the device can be installed sufficiently even if the distance h between the trailer cargo beds is reduced. It is possible and the trailer bed height can be reduced. The mounting position of the gear can also be adjusted by the timing belt, so strict positioning is unnecessary.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. Embodiment FIG. 1 shows the entire device of the present invention. The same members as those in the past are designated by the same reference numerals. As shown in detail in FIG. 2, the front portion F of the trailer 1 has a gear 7 that rotates with the king pin 6 between the upper surface 26 and the lower surface 27 of the loading platform 25, above the king pin 6 protruding downward, and the gear 7. A gear 8 is provided which is connected to the gear 7 by a timing belt 9. Gear 8
The rotating shaft of is connected to the hydraulic control valve 10 and transmits the rotation amount of the gear 8 to the hydraulic control valve 10.

The hydraulic control valve 10 is connected to the flow control valve 11 by a hydraulic pipe 21, and supplies the hydraulic pressure from the hydraulic drive source 23 provided to the tractor 2 through the flow control valve 11 according to the rotation amount of the gear 8. Hydraulic mechanism 5 through hydraulic pipe 20
To operate the hydraulic cylinders 12 and 13 of the hydraulic mechanism 5 to displace the axles of the rear wheels 3 and 4 of the trailer 1.

The operation of the hydraulic steering system of the present invention will be described. As is well known as a structure for connecting a trailer and a tractor, a king pin 6 projecting from the lower front portion of the trailer 1 is connected to a coupler portion of the tractor 2 ( When it is engaged with (not shown), the rotary plate 24 formed integrally with the kingpin 6 is fixed to the coupler portion, and the tractor 2 and the trailer 1 are connected.

When the tractor 2 is rotationally displaced while traveling,
The kingpin 6 and the rotary plate 24 rotate in accordance with the rotation,
This rotation is transmitted to the gear 7 to rotate the gear 8 via the timing belt 9. The hydraulic control valve 10 operates according to the rotation amount of the gear 8, and the hydraulic pressure from the hydraulic drive source 23 provided on the tractor 2 side is supplied to the hydraulic mechanism 5 through the hydraulic pipes 22 and 21, the flow control valve 11, and the hydraulic pipe 20. send.

The hydraulic pressure sent to the hydraulic mechanism 5 is sent to hydraulic cylinders 12 and 13 as shown in detail in FIG.
Operate the hydraulic cylinders 12 and 13 to move the triangular lever 1
4 and 15 are rotated to the positions shown by the dotted lines. Triangular lever 1
The connecting rods 16 and 17 move according to the rotation of 4 and 15,
The levers 18 and 19 rotate to the positions indicated by the dotted lines, and accordingly, the rear wheels 3 and 4 of the trailer rotate to the positions 3a and 4a indicated by the dashed lines corresponding to the rotation of the tractor,
Smooth rotation is performed.

[0013]

As described above, according to the present invention, since the transmission device for the rotational displacement of the tractor installed between the trailer cargo beds can be made smaller, the height of the cargo bed can be lowered and the loading work on the cargo bed can be facilitated. The driving safety increases.

[Brief description of drawings]

FIG. 1 is an overall schematic plan view of a hydraulic steering device of the present invention.

FIG. 2 is a partial schematic cross-sectional view showing a main part of a front portion of the trailer shown in FIG.

FIG. 3 is a schematic plan view showing a rotating state of a rear wheel of the trailer of FIG.

FIG. 4 is a schematic front view of a main part of a trailer.

FIG. 5 is a schematic cross-sectional view showing a conventional rotational displacement transmission device for a tractor installed in the front part of a trailer.

[Explanation of symbols]

 1 Trailer 2 Tractor 3 Rear Wheel 4 Rear Wheel 5 Hydraulic Mechanism 6 King Pin 7 Gear 8 Gear 9 Timing Belt 10 Hydraulic Control Valve 11 Flow Control Valve 12 Hydraulic Cylinder 13 Hydraulic Cylinder 14 Triangle Lever 15 Triangle Lever 16 Connecting Rod 17 Connecting Rod 18 Lever 19 Lever 20 Hydraulic piping 21 Hydraulic piping 22 Hydraulic piping 23 Hydraulic drive source 24 Rotating plate 25 Loading platform 26 Loading platform upper surface 27 Loading platform lower surface 28 Bevel gear 29 Bevel gear F Trailer front part

Claims (1)

[Claims] 1. A rotational displacement of a tractor that pulls a trailer during traveling is transmitted to an axle of a rear wheel of the trailer via a hydraulic mechanism provided on the trailer, and the rear wheel of the trailer is rotated in accordance with the rotation of the tractor. In the trailer hydraulic steering device, a king pin that engages with the coupler portion of the tractor and transmits the rotation of the tractor is projected below the front part of the trailer, and a gear that rotates together with the king pin is provided above the king pin, A hydraulic steering device for a trailer, comprising: a gear connected to a gear and a timing belt to rotate to operate the hydraulic mechanism via a hydraulic control valve.