JPH07165096A - Total hydraulic steering device - Google Patents

Abstract

PURPOSE:To avoid the interference of a pipe with a front PTO shaft by extending a flexible pipe for hydraulic cylinder so as to be inclined downward as it is extended forward from a front PTO shaft and a hydraulic cylinder, and after turning it, extending the flexible pipe under the hydraulic cylinder. CONSTITUTION:A steering lever 6 is supported by a vertical shaft 7 through a fitting part 5 inside of an axle frame 3 projected in front of an engine 2 of a tractor freely to be turned around the vertical shaft 7, and a hydraulic cylinder 8 arranged in the nearly fore and aft direction of one side inside of the axle frame 3 is connected to one end of the steering lever 6, and a piston rod 9 of the hydraulic cylinder 8 is supported by the axle frame 3 freely to be turned. A flexible pipe is extended so as to be separated from the front PTO shaft 4 and the hydraulic cylinder 8 to the other side of the axle frame 3 and so as to be inclined downward from over the steering lever 6 as it is extended forward and so as to be extended under the hydraulic cylinder 8 after it is turned.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fully hydraulic steering system for a traveling vehicle such as a tractor.

[0002]

2. Description of the Related Art As a conventional full-hydraulic steering device for a tractor, as disclosed in Japanese Examined Patent Publication No. 1-21033, a steering lever is rotated around a vertical axis through an attachment portion inside an axle frame. It is supported freely, and one end of the steering lever is connected to a hydraulic cylinder arranged in the front-rear direction on one side inside the axle frame, the piston rod of the hydraulic cylinder is pivotally supported on the axle frame, and pressure oil is supplied to the hydraulic cylinder. A flexible pipe is connected to the hydraulic cylinder by making a U-turn from the engine side on the front side of the hydraulic cylinder.

The flexible pipe is located at substantially the same height from the engine side to the U-turn portion and the hydraulic cylinder mounting end, and is connected to the side surface of the hydraulic cylinder opposite to one side of the axle frame.

[0004]

In the above-mentioned prior art, since the flexible pipe has the same height from the engine side to the side surface of the hydraulic cylinder, the radius of curvature of the U-turn portion is small, and the flexible pipe bends and extends due to the movement of the hydraulic cylinder. The burden is heavy. By the way, in order to increase the radius of curvature of the U-turn part, it suffices to connect the flexible pipe to a portion of the hydraulic cylinder close to one side of the axle frame. If the front PTO shaft projects from the engine, it will interfere with the front PTO shaft if it is passed through.

According to the present invention, the flexible pipe is extended downward from the front PTO shaft and the hydraulic cylinder to the other side of the axle frame, is inclined downward as it goes forward, and extends below the hydraulic cylinder after a U-turn. Thus, it is an object of the present invention to provide an all-hydraulic steering device capable of increasing the radius of curvature of the U-turn portion and avoiding interference with the front PTO shaft.

[0006]

The concrete means for solving the problems in the present invention is the engine 2 to the axle frame 3.
And a front PTO shaft 4 above the axle frame 3 project forward, and a steering lever 6 is supported inside the axle frame 3 via a mounting portion 5 so as to be rotatable about a vertical axis 7, and at one end of the steering lever 6. A flexible pipe 10 that connects a hydraulic cylinder 8 arranged substantially in the front-rear direction to one side inside the axle frame 3, pivotally supports a piston rod 9 of the hydraulic cylinder 8 on the axle frame 3, and supplies pressure oil to the hydraulic cylinder 8. Is connected to the hydraulic cylinder 8 by making a U-turn on the front side of the hydraulic cylinder 8 from the engine 2 side, and separating the flexible pipe 10 from the front PTO shaft 4 and the hydraulic cylinder 8 to the other side of the axle frame 3 and the steering lever. 6 is inclined downward from the upper side toward the front, and is extended below the hydraulic cylinder 8 after U turns. It is.

[0007]

[Function] The flexible pipe 10 is the front PTO shaft 4
And the U-turn part A is formed so as to be separated from the hydraulic cylinder 8 to the other side of the axle frame 3 and inclined downward from above the steering lever 6 toward the front, and at the same height, the U-turn part A is formed. The radius of curvature of the flexible pipe 10 is larger than that in the case where the hydraulic cylinder 8 is formed, and since it extends below the hydraulic cylinder 8 after the U-turn, it is provided on the side surface of the hydraulic cylinder 8 opposite to the one side of the axle frame 3. Since the distance between both ends is longer than the connection, the radius of curvature becomes larger.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. In FIGS. 1 to 3, reference numeral 1 denotes a steering device for the front wheels of the tractor 13, which is of a full hydraulic type, and pressure oil from a steering controller (indicated by reference numeral 45 in FIG. 6) operated by the steering wheel 14 is hydraulic pressure. It can be supplied to the cylinder 8.

The tractor 13 is an engine 2 which constitutes a vehicle body.
The axle frame 3 is projected forward from the axle frame 3. The axle frame 3 has left and right side frames 3A and a front frame 3B, and the inside thereof is a space. The axle frame 3 is mounted on the axle case 1 via front and rear center pin pedestals 15.
6 is swingably supported around the center pin. Front wheels 17 that are steered by the steering device 1 are suspended at the left and right ends of the axle case 16.

A front PTO shaft 4 projects forward from the crankshaft of the engine 2.
The TO shaft 4 is connected to an input shaft of a front transmission device 18 mounted on the front portion of the axle frame 3. The front transmission 18 is for driving a working machine 19 of a mower attached to the lower abdomen of the tractor 13 or a snow remover provided in the front, and the front transmission 18 is not provided, but the front PTO is not provided. The shaft 4 may be directly connected to the input shaft of the work machine 19.

Left and right frames 3A of the axle frame 3
The vertical axis 7 is attached to the vertical axis 7 via the upper and lower receiving plates 21 and 22 that form the attachment portion 5.
A midway portion of the steering lever 6 having a character shape is rotatably fitted. The vertical axis 7 is axially restricted and prevented from rotating by a stopper plate 23 screwed to the lower receiving plate 22, and does not rotate with respect to the upper and lower receiving plates 21 and 22.
Their processing is easy.

The steering lever 6 is a first lever portion 6A.
Is bent to the lower side of the lower receiving plate 22, two tie rod ends 24 are attached to one end thereof, and tie rods 25 for interlocking with the left and right front wheels 17 are connected to each tie rod end 24. This left and right tie rod 6
A turnbuckle 26 is provided on at least one of them, and the length thereof can be adjusted for performing toe-in adjustment or the like.

The second lever portion 6B of the steering lever 6
Is located within the axle frame 3 and is shorter than the first lever portion 6A, and the trunnion shaft 8A of the hydraulic cylinder 8 is pivotally connected to one end of this. The hydraulic cylinder 8 is a return type cylinder in which a piston rod 9 projects from both sides, and the tip of the piston rod 9 projecting forward has a vertical pin 2
A bracket 28 is pivotally supported via 7 and the bracket 28 is fixed to the inner surfaces of the corners of the left frame 3A and the front frame 3B. That is, with respect to the front PTO shaft 4 passing through the center of the tractor 13 in the left-right direction, the mounting portion 5 and the vertical axis 7 are displaced to the right, and the hydraulic cylinder 8 is displaced to the left.

Reference numeral 10 denotes two flexible pipes for connecting the hydraulic cylinder 8 and the hydraulic pump attached to the engine 2, and has a hose portion 10A and a connecting pipe portion 10B. The hose portion 10A is an axle from the engine 2 side. Frame 3
Passing through the outer side of the axle casing 16 into the axle frame 3 above the axle casing 16 and attached by a stopper 31 on the upper surface of the upper receiving plate 21. The first lever portion 6A projects forward and makes a U-turn. The turn portion A is bound by the binding body 32, and the connection pipe portion 10B is provided at the tip thereof.

The connecting pipe portion 10B has a steel pipe and an elbow, and one connecting pipe portion 10B is connected to the lower front portion of the hydraulic cylinder 8 and the other connecting pipe portion 10B is located below the hydraulic cylinder 8 and close to the hydraulic cylinder 8. It is connected to the rear upper part of the hydraulic cylinder 8 through a space between the one side (left side) side frame 3A. Therefore, the flexible pipe 10 extends from the front PTO shaft 4 and the hydraulic cylinder 8 to the axle frame 3
On the other side (right side) and from the steering lever 6 toward the front, it inclines downward and extends below the hydraulic cylinder 8 after a U-turn at the U-turn portion A at the front end. , One flexible pipe 10 is connected to the lower side of the hydraulic cylinder 8, and the other flexible pipe 10 is further connected to the upper side of the hydraulic cylinder 8 through between the hydraulic cylinder 8 and one side (left side) of the axle frame 3. Has been done.

The U-turn portion A of the flexible pipe 10 is located in front of the vertical axis 7, but since the first lever portion 6A is located below the lower receiving plate 22, it does not interfere with it and the connecting pipe portion 10B. Is connected at a position farther from the mounting portion 5 in the hydraulic cylinder 8, the U-turn portion A has a radius of curvature as large as possible, and the bending load is small.

3 to 5, a front wheel diff device is built in the center of the axle case 16, and power is transmitted to the front wheel diff device from a front wheel drive transmission case 35 provided under the transmission case 34 of the tractor 13. The transmission shaft penetrates the center pin of the axle case 16, and the transmission shaft is protected by the shaft cover 36. The shaft cover 36 is formed by fitting a front cover 36A on the side of the center pin cradle 15 and a rear cover 36B on the side of the front wheel drive transmission case 35, and is connected by a screw 37 at the overlapping portion. The hole through which the screw 37 of the front cover 36A penetrates is an elongated hole 38 in the axial direction, which allows the cover lengths of the front and rear covers 36A and 36B to be adjusted, and the screw hole into which the screw 37 is screwed in the rear cover 36B. In addition to 39, a fitting mark / drainage hole 40 is formed.

3, 6 and 7 show an example of the mounting structure of the engine start check switch. A steering shaft 42 for mounting the steering wheel 14 and operating a steering controller 45 is protected by a handle post 43, and the handle post 43 is provided via a tilt support 44 so as to be tiltable about a fulcrum 46. .

A forward / reverse switching operation shaft 47 for operating a forward / backward switching device of the transmission system of the transmission is arranged substantially along the handle post 43. The forward / backward switching operation shaft 47 has an upper portion via a ball joint 48. It is supported by 43, and the lower part is connected to the operation transmission shaft 49 via a universal joint 50. A forward / reverse switching lever 51 is supported on the upper end of the forward / backward switching operation shaft 47 so as to be swingable around the front / rear axis. An engaging pin 52 is provided at the base of the forward / reverse switching lever 51 so that it can be engaged with an engaged portion 53 provided on the handle post 43.

The forward / reverse switching lever 51 is in the neutral position when the engagement pin 52 is engaged with the engaged portion 53 (state shown in FIG. 7), and the grip portion is pulled up from this position (engagement pin 53). The forward / reverse switching device can be operated by lowering (52) and moving it back and forth. At the base of the forward / backward switching lever 51, a check switch 55 provided at the upper end of the forward / backward switching operation shaft 47 is operated. An operating piece 56 is provided to allow the operation piece 56 to operate.

The check switch 55 is incorporated in the engine start circuit, and when the forward / reverse switching lever 51 is in the neutral position, it is actuated by the operating piece 56 to allow the engine 2 to be started. When 51 is rocked back and forth and the forward / reverse switching device is in the forward or reverse position, the check switch 55 is turned off to check the start of the engine 2 and the tractor 13 is started.
It is designed to prevent the sudden start of the.

By providing the check switch 55 at the upper end of the forward / reverse switching operation shaft 47, the handle post 4
When 3 is tilted about the fulcrum 46, the forward / reverse switching operation shaft 47 tilts around the universal joint 50, so that the forward / reverse switching operation shaft 47 is displaced axially with respect to the handle post 43. However, the positional relationship between the operating piece 56 and the check switch 55 is unchanged, and the check switch 55 is ensured to operate.

The present invention is not limited to the above embodiment, but can be variously modified. For example, front wheel 1
Although 3 is the steering wheel, the rear wheel may be the steering wheel,
The vertical axis 7 may be offset to the right and the hydraulic cylinder 8 may be offset to the left with respect to the front PTO shaft 4, and the entire length of the flexible pipe 10 may be formed of a hose.

[0024]

According to the present invention described in detail above, the flexible pipe 10 that makes a U-turn from the engine 2 side to the front side of the hydraulic cylinder 8 to connect to the hydraulic cylinder 8 is connected to the front PTO shaft 4 and the hydraulic cylinder 8 from the axle. The U-turn portion of the flexible pipe 10 is separated from the other side of the frame 3 and inclined downward from above the steering lever 6 as it goes forward and extends below the hydraulic cylinder 8 after a U-turn. The radius of curvature of A can be made as large as possible and interference with the front PTO shaft 4 can be avoided.

[Brief description of drawings]

FIG. 1 is a plan view showing an embodiment of the present invention.

FIG. 2 is a sectional view taken along line XX of FIG.

FIG. 3 is a side view of the front part of the tractor.

FIG. 4 is a sectional view of a shaft cover.

5 is a view taken in the direction of the arrow Y in FIG.

FIG. 6 is a side view showing a mounting structure of an engine start check switch.

FIG. 7 is a sectional view taken along line ZZ in FIG.

[Explanation of symbols]

 1 Steering device 2 Engine 3 Axle frame 4 Front PTO shaft 5 Mounting part 6 Steering lever 7 Vertical axis 8 Hydraulic cylinder 9 Piston rod 10 Flexible pipe

Claims (1)

[Claims] 1. Engine (2) to axle frame (3)
And the front PTO shaft (4) above the axle frame (3) are projected forward, and the steering lever (6) is rotated around the vertical axis (7) through the mounting portion (5) inside the axle frame (3). A hydraulic cylinder (8), which is movably supported, is connected to one end of the steering lever (6) substantially in the front-rear direction inside one side of the axle frame (3), and a piston rod (9) of the hydraulic cylinder (8) is connected. ) Is pivotally supported on the axle frame (3), and a flexible pipe (10) for supplying pressure oil to the hydraulic cylinder (8) is turned from the engine (2) side to the front side of the hydraulic cylinder (8) to make a U-turn. 8) connected to the flexible pipe (1
0) to the front PTO shaft (4) and hydraulic cylinder (8)
To the other side of the axle frame (3) and from the upper side of the steering lever (6) toward the front, tilt downward, and after U turns, extend to the lower side of the hydraulic cylinder (8). All-hydraulic steering device featuring.