JPH0324454Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a power steering device for a vehicle.

[Conventional technology]

2. Description of the Related Art In tractor vehicles, power steering devices are being adopted as vehicle bodies become larger. There are various types of power steering devices. For example, a steering arm that can swing freely around a vertical axis is provided on the front axle bracket that suspends the front axle case, and this steering arm is operated by a hydraulic cylinder. There is one in which the front wheels are steered via a pair of left and right tie rods.

[Problem that the invention attempts to solve]

However, since conventional power steering devices only use one double-acting hydraulic cylinder, the volume of the cylinder chamber is different on the side with and without the piston rod, and when the steering wheel is operated at the same angle, However, there was a problem that the turning angles of the front wheels were not equal on the left and right sides.

Furthermore, since the hydraulic cylinder is conventionally provided in an exposed manner, there is a risk that the piston rod may be damaged.

[Means for solving problems]

In the present invention, as a specific means to solve such conventional problems, a front axle bracket 3 is mounted in front of the engine 2 mounted on the front part of the vehicle body 1, and front wheels 10 are mounted on both left and right ends. A front axle case 8 having a front axle case 8 is suspended on a front axle bracket 3 by a center shaft 7, and a steering arm 13 is provided on the front axle bracket 3 and is swingable around a vertical axis 12 by hydraulic cylinders 14 and 15. In a power steering system for a vehicle in which the front wheels 10 are steered via the left and right tie rods 16 at 13, the front axle bracket 3 is formed into a box shape having an internal space 22, and the vertical shaft 12 is rotated within this internal space 22. The steering arm 13 is pivotally supported on the front axle bracket 3, and two sets of hydraulic cylinders 14 and 15 for operating the steering arm 13 are installed in the interior space 22 on the side opposite to the engine 2 with respect to the front axle case 8. The two sets of hydraulic cylinders 14 and 15 are connected so as to operate in opposite directions.

[Effect]

When the handle 5 is rotated, the valve works,
Two sets of hydraulic cylinders 14 and 15 operate in opposite directions to swing the steering arm 13 about the vertical axis 12. Then, if the steering arm 13 swings,
The front wheels 10 are steered around the kingpin via the left and right tie rods 16.

〔Example〕

Hereinafter, the present invention will be described in detail with reference to the illustrated embodiment. In FIGS. 3 and 4, 1 is a tractor body, and includes an engine 2 at the front, a front axle bracket 3, etc. mounted in front of the engine 2. The engine 2 is covered with a bonnet 4. 5 is a handle, which is linked to a power steering valve (not shown). A front axle case 8 is suspended on the front axle bracket 3 by a center bearing stand 6 and a center shaft 7 on the lower side, and a front wheel case 11 supporting a front wheel 10 is mounted on gear cases 9 at both ends of the front axle case 8. It is supported around a king pin (not shown) so that it can be steered.

The front axle bracket 3 is box-shaped, and has a steering arm 13 supported on the vertical shaft 12 inside, and two sets of hydraulic cylinders 1 for operating the steering arm 13.
4, 15 are incorporated, and the hydraulic cylinder 1
4 and 15 are arranged on the side opposite to the engine 2 with respect to the front axle bracket 8. The steering arm 13 is connected to a knuckle arm 17 of each front wheel case 8 via left and right tie rods 16.

As shown in FIGS. 1 and 2, the front axle bracket 3 is box-shaped and includes an upper wall 18, a lower wall 19, and left and right side walls 20, 21, and has an internal space 22. Attachment part 23 to engine 2
Further, mounting seats 24 for the center bearing stand 6 are formed on the lower side of the lower wall 19 so as to protrude downward from the front and back. The vertical shaft 12 is located approximately in the center of the front axle bracket 3 in the longitudinal direction,
Bolts 2 are attached to the boss portion 25 of the lower wall 19 and the upper wall 18.
6 is rotatably supported by a bearing case 27 attached thereto. The steering arm 13 is attached to the upper wall 18
It is fixed to the vertical shaft 12 with a set bolt 28 in an internal space 22 between the lower wall 19 and the lower wall 19 . This steering arm 13 extends diagonally rearward and downward from the base on the vertical axis 12 side, and is guided downward through a hole 29 in the lower wall 19, and a tie rod 16 is connected to the rear end via a tie rod end 30. has been done.
There are small arm parts 3 on both sides of the base of the steering arm 13.
1 and 32 are formed to protrude left and right. Two sets of hydraulic cylinders 14 and 15 are connected to the front axle bracket 3.
The hydraulic cylinders 14, 15 are arranged in an internal space 22 in the front-rear direction, left and right substantially parallel to each other, and each hydraulic cylinder 14, 15 is a double-acting cylinder of the same size, comprising cylinder bodies 33, 34, pistons 35, 36, and piston rods 37, 38. The front end sides of the cylinder bodies 33 and 34 are connected to the support shafts 39 and 4 at the front end of the front axle bracket 3.
0, and the tips of the piston rods 37, 38 are connected to the respective arm portions 31, 32 via connectors 41, 42 and connecting pins 43, 44. The support shafts 39, 40 are inserted into the cylindrical portions 45, 46 of the lower wall 19 and the upper wall 18, and the cylindrical portions 45, 46 are bolted to the lower wall 19 via brackets.

Cylinder bodies 33 of hydraulic cylinders 14, 15,
34 has joint cylinders 49, 50 that project slightly outward from the holes 47, 48 of the side walls 20, 21.
are fixed on the outside, respectively, and flexible hoses 53, 54 are connected to the respective cylindrical bodies 49, 50 via joints 51, 52. As shown in FIGS. 5 and 6, the flexible hoses 53 and 54 are provided on both left and right sides of the front axle bracket 3 facing rearward, and the flexible hose 54 on one side is attached to the rear side of the front axle bracket 3. It is connected to a coupling block 57 via a side coupling 56. The flexible hose 53 on the other side is connected to a fixed joint 55 at a bracket 58 on the other rear side of the front axle bracket 3, and the joint 55 is connected to the joint block via a piping 59 such as a steel pipe passing above the front axle case 3. 57. Joint block 5
Inside the hydraulic cylinder 7, a hydraulic cylinder 1 is installed so that two sets of hydraulic cylinders 14 and 15 operate in opposite directions.
4 and 15 in antiparallel is formed, and the joint block 57 is connected to a valve via a pipe 60. A protective tube 61 made of rubber or the like is fitted into the piping 59 at a necessary portion. 62 is a stopper bolt. 63 is a hole in the upper wall 18, and 64 is a hole in the lower wall 19.

In the above configuration, if the handle 5 is operated,
The valve is activated, and the two sets of hydraulic cylinders 14 and 15 connected in antiparallel extend and contract in opposite directions. For example, as shown in FIG. 1, if the hydraulic cylinder 14 expands, the hydraulic cylinder 15 contracts,
Due to the expansion and contraction operations of these hydraulic cylinders 14 and 15, the steering arm 13 swings about the vertical axis 12 in the direction indicated by arrow a. This movement of the steering arm 13 is transmitted to each front wheel 10 via the left and right tie rods 16, and each front wheel 10 steers rightward around the king pin. In this case, two sets of hydraulic cylinders 1
4 and 15 operate in opposite directions, it is possible to eliminate variations in the turning angle of the front wheels 10 due to the presence or absence of the piston rods 37 and 38 when steering in either the left or right direction.

Furthermore, due to the structure, the front axle bracket 3 installed in front of the engine 2 at the front of the vehicle body 1 is box-shaped, and the steering arm 13, vertical shaft 12, and two sets of hydraulic cylinders 14, 15 are arranged in the internal space 22. Because I am doing
These can be protected by the front axle bracket 3, improving durability. By arranging the two sets of hydraulic cylinders 14 and 15 in the front-rear direction and arranging them substantially parallel to the left and right, the width of the front axle bracket 3 can also be reduced.
Moreover, the flexible hoses 53 and 54 are connected to the hydraulic cylinder 1.
By providing it separately from the front axle bracket 3 and outside the front axle bracket 3, it is possible to prevent interference with the hydraulic cylinders 14, 15, the steering arm 13, etc. that move during steering.

[Effect of idea]

According to the present invention, the two operating the steering arm 13
Since a set of hydraulic cylinders 14 and 15 are provided and these two sets of hydraulic cylinders 14 and 15 are connected so that they operate in opposite directions, the cutting angle will vary due to the difference in volume of the cylinder chamber due to the presence or absence of the piston rod. will not occur. Furthermore, due to the structure, the front axle bracket 3 is box-shaped, and the steering arm 13, vertical shaft 12, and two sets of hydraulic cylinders 14, 15 are arranged in the internal space 22, so these are protected by the front axle bracket 3. and improves durability. Furthermore, the hydraulic cylinders 14 and 15 are located on the opposite side of the engine 2 with respect to the front axle case 3, which is suspended by the center shaft 7 on the front axle bracket 3 in front of the engine 2, so that they are not affected by the heat of the engine 2. There is no. That is, the hydraulic cylinders 14 and 15 are connected to the engine 2.
Since it is far away from the front, the oil temperature of the hydraulic cylinders 14 and 15 will not rise due to the heat of the engine 2, and the oil seals of the hydraulic cylinders 14 and 15 will not deteriorate.

In addition, since the hydraulic cylinders 14 and 15 are located in the internal space of the box-shaped front axle bracket 3, they can be placed at a sufficiently higher position than when they are installed on the front axle case 8 itself, and are protected against muddy water while driving. etc. can be protected from Moreover, the hydraulic cylinders 14,1
Although the hydraulic cylinders 14 and 1 can be placed at a sufficiently high position, the hydraulic cylinders 14 and 1 are not located inside the box-shaped front axle bracket 3.
5, it will not interfere with other equipment mounted on the front axle bracket 3 in front of the engine 2.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, in which Fig. 1 is a cross-sectional plan view of the main part, Fig. 2 is a view taken in the direction of - arrow in Fig. 1,
3 is a side view of the front part of the tractor, FIG. 4 is a plan view thereof, FIG. 5 is a plan view of the piping system, and FIG. 6 is a side view thereof. DESCRIPTION OF SYMBOLS 1...Tractor body, 3...Front axle bracket, 8...Front axle case, 10...Front wheel, 12...
... Vertical axis, 13 ... Steering arm, 14, 15 ... Hydraulic cylinder, 16 ... Tie rod, 22 ... Internal space.

Claims (1)

[Scope of utility model registration request] A front axle bracket 3 is mounted in front of the engine 2 mounted on the front part of the vehicle body 1, and a front axle case 8 having front wheels 10 at both left and right ends is attached to the center shaft 7.
A steering arm 13 is provided on the front axle bracket 3 and is swingable around a vertical axis 12 by hydraulic cylinders 14 and 15. In a power steering system for a vehicle that steers the front wheels 10, the front axle bracket 3 is formed into a box shape having an internal space 22, and within this internal space 22, the steering arm 13 is connected to the front axle bracket by the vertical shaft 12. Two sets of hydraulic cylinders 14 and 15 are provided in the interior space 22 on the side opposite to the engine 2 with respect to the front axle case 8, and these two sets of hydraulic cylinders 14 and 15 are pivotally supported on the steering arm 3 and operate the steering arm 13. ，
15 are connected to each other so as to operate in opposite directions.