JP2604071Y2 - Vehicle hydraulic steering system - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic steering system for a vehicle, in which a front wheel is turned around a kingpin by the expansion and contraction of a steering hydraulic cylinder to perform a steering operation.

[0002]

2. Description of the Related Art In a working vehicle such as an aerial work vehicle or a crane vehicle, a front beam composed of a cylindrical body is installed at the front end of a traveling frame extending in the front-rear direction of the vehicle in the left-right direction. In the part, while pivoting the left and right front wheels via the kingpin and knuckle arm,
There is a hydraulic steering apparatus for a vehicle in which a steering hydraulic cylinder is arranged along the front beam, and the expansion / contraction displacement of the steering hydraulic cylinder is transmitted to the knuckle arms of the left and right front wheels.

[0003] A conventional hydraulic steering system of this type is constructed, for example, as shown in FIG.

[0006] That is, in FIG. 6, reference numeral 2 denotes a traveling frame of a vehicle, and 3 denotes a front beam. Left and right front wheels 6 can be turned via a king pin 5 on a bracket 4 installed at an end of the front beam 3. It is pivoted. A swing arm 7 is attached to the front central portion of the front beam 3, and a steering hydraulic cylinder 8 is interposed between the swing arm 7 and one end of the front beam 3, and the swing arm 7 is Connecting rods 12 are respectively arranged between the arm 7 and the knuckle arm 11 of each front wheel 6, and the telescopic displacement of the steering hydraulic cylinder 8 causes the front wheel 6
And the steering operation is performed. In addition, there is a hydraulic steering device that is provided below the front beam 3.

[0005]

In the hydraulic steering apparatus having such a structure, the steering hydraulic cylinder 8 and the connecting rod 12 are located in front of the front beam 3, so that as the vehicle travels, They may come into contact with obstacles and the like.

Further, the hydraulic steering device is mounted on the front beam 3.
, The road clearance of the vehicle is reduced, and the hydraulic steering device is more likely to come into contact with an obstacle or the like as the vehicle travels.

The present invention has been made based on such a background, and an object of the present invention is to prevent a hydraulic steering apparatus of this kind from contacting an obstacle or the like as the vehicle travels. is there.

[0008]

Means for Solving the Problems In order to achieve this object, the invention of claim 1 wherein is the traveling frame extending in the longitudinal direction of the vehicle, set up a front beam of the cylindrical body in the lateral direction, the At both ends of the front beam, the left and right front wheels are pivotally supported via a kingpin and a knuckle arm, and a steering hydraulic cylinder is arranged along the front beam. In a hydraulic steering system for a vehicle that transmits to and steers to the left and right front wheel knuckle arms, the left and right front wheel knuckle arms are connected by a connecting rod, and the steering hydraulic cylinder is connected to the front beam and one of the front beam. interposed between the front wheel knuckle arm, further, the cylindrical body of one of said connecting rod and a hydraulic cylinder for steering the front beam
And the other immediately after the front beam , in front of it
It is characterized by being disposed so as to penetrate the traveling frame . The invention according to claim 2 is based on claim 1.
The other is a transparent frame formed by partitioning the running frame with a steel plate.
It is characterized by being penetrated by a hole.

[0009]

According to the invention, one of the connecting rod and the steering hydraulic cylinder is disposed inside the front beam, and the other is disposed behind the front beam. As the vehicle travels, the front beam comes into contact with obstacles and the like, and the connecting rod and the steering hydraulic cylinder are not positioned below the front beam, so that they do not reduce the load clearance.

Therefore, it is possible to reduce the possibility that the connecting rod and the hydraulic cylinder for steering are directly damaged by an obstacle or the like during traveling of the vehicle and damaged.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to an embodiment shown in the drawings. The vehicle in this embodiment is an aerial work vehicle.

First, an overall outline of the aerial work vehicle will be described.

In FIG. 2, reference numeral 21 denotes an aerial work vehicle,
22 is a traveling body, and 23 is a swivel.

The revolving base 23 is configured to be revolvable about a vertical axis N on the traveling body 22. A pair of left and right support brackets 24 are integrally formed of a thick steel plate on the upper part of the revolving base 23. I have.

A base end 25a of a telescopic boom 25 is disposed between the support brackets 24 and is pivotally supported by a pivot 26. The base end 25a of the telescopic boom 25 is installed between the base end 25a of the telescopic boom 25 and the swivel base 23. The telescopic boom 25 can be driven up and down in the vertical plane by extending and retracting the raised and lowered hydraulic cylinder 28.

The telescopic boom 25 of this embodiment is of a three-stage type, and can be driven to expand and contract by a hydraulic cylinder (not shown). Equipped with this bucket 27
The operator can get on and perform required altitude work.

The traveling body 22 of the aerial work vehicle 21
Is configured as follows.

FIG. 1 is a top view of the traveling body 22. A front wheel 31 and a rear wheel 32 are provided before and after the traveling body 22.
The front wheels 31 function as steering wheels, and the rear wheels 32 function as driving wheels.

A rectangular tubular traveling frame 33 extending in the front-rear direction is provided in parallel on both left and right sides of the traveling body 22. A front beam 34 formed in a rectangular cylindrical shape is fixed between the front ends of the traveling frames 33, and a rectangular cylindrical rear beam 35 is similarly fixed between the rear ends of the traveling frame 33. ing.

Brackets 36 are provided at both ends of the front beam 34, respectively.

These brackets 36 are formed in a substantially right triangle so as to avoid interference with the front wheel 31. The rear walls 34 of the front beam 34 are formed by these brackets 36.
The king pin 37 is installed at a position that is approximately an extension of a.

The knuckle arms 38 of the front wheels 31 are pivotally supported via these king pins 37, respectively.
Each of the front wheels 31 is swingable around the king pin 37.

The rear wall 34 of the front beam 34
A steering hydraulic cylinder 41 is installed at a.

In this embodiment, the steering hydraulic cylinder 41
Is a hydraulic cylinder composed of a single-rod double-acting cylinder, which has a cylinder body 41a and a piston rod 41b, and a connection fitting 42 for connecting to the knuckle arm 38 of one of the front wheels 31 at the tip of the piston rod 41b. Is attached. Note that a double rod double-acting cylinder may be used as the steering hydraulic cylinder 41. In this case, the flow characteristic of the pressure oil accompanying the extension operation and the contraction operation of the hydraulic cylinder is uniform, and Accordingly, there is an advantage that the turning characteristics are equal when the vehicle makes a right turn and a left turn.

In this embodiment, the distal end position of the piston rod 41b to which the connection fitting 42 is attached is inside the end of the front beam 34 when the steering hydraulic cylinder 41 is in the maximum extension state, and the steering hydraulic pressure is In the minimum contracted state of the cylinder 41, it is a position where it is not accommodated in the cylinder main body 41a (see FIG. 3).

At a position behind the front beam 34, the running frames 33 provided on both sides are provided with through holes 43 defined by a steel plate 43a. The connecting rods 44 attached to the knuckle arms 38 of the front wheels 31 on both sides are inserted therethrough.

Therefore, the steering hydraulic cylinder 41
The front wheels 31 on both sides are steered and driven in conjunction with the expansion and contraction of
A hydraulic steering device is configured.

In the hydraulic steering apparatus configured as described above, the hydraulic pressure from the engine-driven hydraulic pump 45 provided on the swivel base 23 extends through the swivel joint 46 and inside the traveling frame 33. The air is supplied to the steering hydraulic cylinder 41 through a hydraulic line 47.

An opening 34b is formed in the center upper surface of the front beam 34, and the hydraulic conduit 47 is connected to the cylinder body 41a of the steering hydraulic cylinder 41 via the opening 34b. The opening 34b also has the advantage of improving the workability of the mounting operation by using the steering hydraulic cylinder 41 in the mounting operation when the steering hydraulic cylinder 41 is installed in the front beam 34.

In this embodiment, the rear wheels 32 as drive wheels are driven by hydraulic motors 48 coaxially mounted inside each rear wheel 32. The vehicle is driven to travel by supplying hydraulic pressure from a hydraulic pump 45 through a swivel joint 46 through a hydraulic line 49.

According to such a hydraulic steering apparatus, the front wheel 31 as a steered wheel is steered by the hydraulic pressure from the hydraulic pump 45, but the front end position of the piston rod 41b to which the connection fitting 42 is attached. Is determined as described above, regardless of the direction in which the front wheel 31 is steered, the piston rod 41b always moves the front beam 3
4.

Therefore, when the aerial work vehicle 21 travels or works such as painting, mud or paint does not adhere to the piston rod 41b, and the steering hydraulic cylinder 41 is less likely to be damaged.

Further, the connection position between the connection fitting 42 and the piston rod 41b does not enter the cylinder body 41a in the minimum contracted state, and is steered without damaging the oil seal and the like installed on the cylinder body 41a. There is an advantage that the hydraulic cylinder 41 for use is less likely to be damaged.

As described above, in this embodiment, the steering hydraulic cylinder 41 is disposed in the front beam 34, and the connecting rod 4 is located behind the front beam 34.
4, even if the aerial work vehicle 21 may come into contact with an obstacle or the like when traveling forward, the front beam 34 may come into contact with the obstacle or the like, and the steering hydraulic cylinder 41 may be used.
In addition, it is possible to prevent the connecting rod 44 from directly contacting an obstacle or the like, and to reduce damage to the steering hydraulic cylinder 41 and the connecting rod 44 without reducing the load clearance.

In the above-described embodiment, the steering hydraulic cylinder 41 is disposed in the front beam 34, and the connecting rod 44 is disposed behind the front beam 34. Instead, the connecting rod 44 may be arranged in the front beam 34 and the steering hydraulic cylinder 41 may be arranged behind the front beam 34.

[0036]

As described above, according to the first aspect of the present invention, one of the connecting rod and the steering hydraulic cylinder is disposed inside the front beam, and the other is the front beam. The front beam comes into contact with obstacles, etc. as the vehicle travels, and the connecting rod and steering hydraulic cylinder are not located below the front beam, which reduces the road clearance. Nor.

Therefore, it is possible to reduce the possibility that the connecting rod and the steering hydraulic cylinder are directly damaged by an obstacle or the like during traveling of the vehicle and damaged.

[Brief description of the drawings]

FIG. 1 is a top view of a traveling body.

FIG. 2 is an overall schematic view of an aerial work vehicle.

FIG. 3 is a top view in which a part of a front portion of the traveling body is cut away.

FIG. 4 is a longitudinal sectional view of the traveling body.

FIG. 5 is a side view of the front beam seen through the front wheel.

FIG. 6 is a front top view of a conventional traveling body.

[Explanation of symbols]

 Reference Signs List 21 aerial work vehicle 31 front wheel 33 traveling frame 34 front beam 37 kingpin 38 knuckle arm 41 steering hydraulic cylinder 44 connecting rod

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) B62D 5/10 B62D 7/08

Claims (2)

(57) [Scope of request for utility model registration] To 1. A traveling frame extending in the longitudinal direction,
A front beam composed of a cylindrical body is installed in the left and right direction, and at both ends of the front beam, the left and right front wheels are pivotally supported via a kingpin and a knuckle arm, and a steering hydraulic cylinder is provided along the front beam. A hydraulic steering device for a vehicle that is arranged and transmits the expansion / contraction displacement of the steering hydraulic cylinder to the knuckle arms of the left and right front wheels, and connects the knuckle arms of the left and right front wheels with a connecting rod.
Also interposed said hydraulic cylinder for steering between the front beam and one of the front wheel knuckle arms, further, one of said connecting rod and the steering cylinder to the cylindrical body of the front beam A hydraulic steering device for a vehicle, wherein the hydraulic steering device is arranged so as to penetrate the traveling frame immediately after the other of the front beams. 2. The vehicle according to claim 1, wherein
The frame is passed through a through hole defined by steel plate.
A hydraulic steering device for a vehicle.