JP3912730B2 - Vehicle front wheel steering device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a vehicle front wheel steering device, and more particularly to a vehicle front wheel steering device in which a hydraulic cylinder device for steering a front wheel is provided along a front axle case.
[0002]
[Prior art]
In this type of vehicle front wheel steering device, a front axle case and a hydraulic cylinder device are provided separately, and the strength of the swing center portion (swing support portion) provided in the front axle case is weakened. Since the distance between the axial center of the case and the axial center of the hydraulic cylinder device increases, it is known that a long stroke of the hydraulic cylinder device is required to obtain a prescribed front wheel turning angle.
[0003]
On the other hand, for example, according to the technique described in Japanese Utility Model Laid-Open No. 5-58560, the front axle case and the hydraulic cylinder for steering the front wheels are integrally fixed by the mounting bracket and the bolt.
[0004]
According to Japanese Patent Laid-Open No. 62-225461, a cylinder cylinder is integrally fixed to a front axle case with a bolt, and a differential drive shaft 102 is mounted via a bearing 101 as shown in FIG. A bearing case 100 is supported, and a cylinder of a hydraulic cylinder 104 for steering the front wheels is integrally bolted to a front axle case 106 below the differential drive shaft 102, and the front axle case is further fixed. Shaft portions 108, 108 project from the front and rear of 106, and the shaft portions 108 are fitted into recesses 112 formed in the attachment devices 110, 110, thereby swinging the front axle case 106 about the longitudinal axis. Supports freely.
[0005]
[Problems to be solved by the invention]
However, according to each of the conventional examples described above, the front axle case and the cylinder case of the hydraulic cylinder for steering the front wheels are integrally fixed by fixing means such as bolts. Compared with this, the effect was inferior in terms of improving (reinforcing) the mechanical strength of the front axle case.
[0006]
Further, if the cylinder case is disposed at a position away from the vertical swing support portion of the front axle case, the effect is similarly inferior in terms of improving (reinforcing) the mechanical strength of the front axle case. .
[0007]
Further, in the conventional example described in the above-mentioned Japanese Patent Application Laid-Open No. 62-225461, the shaft portion 108 protruding from the front axle case 106 is fitted into a recess 112 formed in the mounting device 110 so as to be swingable. Although it is supported, the shaft 108 projecting from the front axle case 106 is processed because the front axle case 106 is long, and therefore it is necessary to rotate it around the axial center in the front-rear direction. Have difficulty.
[0008]
The present invention has been made to solve such a problem, and an object of the present invention is to increase the mechanical strength of the front axle case and to reduce the number of assembling steps. To provide an apparatus.
[0009]
[Means for Solving the Problems]
In order to achieve the object, the invention according to claim 1 is a vehicle front wheel steering device in which a hydraulic cylinder device (30) for steering a front wheel power steering is provided along a front axle case (28).
With integrally molded and a cylinder casing (31) of said front axle case (28) hydraulic cylinder device (30), provided before SL-formed bearing portion to the front axle case (28) and (28a) on the body side A center pin (32a) is rotatably fitted to support the front axle case so that it can swing up and down .
A cylinder case (31) formed integrally with the front axle case (28) is disposed above the bearing portion (28a) .
[0010]
According to a second aspect of the present invention, in the vehicle front wheel steering apparatus according to the first aspect, both ends (32c, 32c) of the front bracket (32) having the center pin (32a) are provided on the left and right sides of the engine (12). attached to the right and left fixed frame extending toward the both sides in the front (36, 36), shorter than the axial length facing length of the left and right fixed frames (36, 36) of the cylinder casing (31) It is characterized by comprising.
[0011]
[Action]
According to the present invention, the front axle case (28) and the cylinder case (31) of the hydraulic cylinder device (30) are integrally formed, whereby the front axle case (28) is reinforced by the cylinder case (31). The mechanical strength of the front axle case (28) is increased, and the cylinder case (31) is disposed above the vertical swing support portion (28a) of the front axle case (28). There is an advantage that the mechanical strength of the front axle case (28) in the vicinity of the vertical swing support portion (28a) where a large load is expected to be applied is increased.
[0012]
In addition, the code | symbol in a parenthesis is for referring drawings, and does not limit this invention at all.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0014]
FIG. 1 is an external perspective view of a tractor to which the present invention is applied. In the figure, a tractor 10 has a traveling machine body 11 including an engine 12, a transmission case 14, and the like, and the traveling machine body 11 is supported by front wheels 16 and rear wheels 18 which are steered wheels. The engine 12 is covered with a hood 20, and a driver seat 22 behind the hood 20 has a handle 24 and a seat 26.
[0015]
2-4 is a figure which shows the structure of the front axle case 28 which comprises a front-wheel steering apparatus, and the hydraulic cylinder apparatus 30 installed along this.
[0016]
In the present embodiment, the front axle case 28 and the cylinder case 31 of the hydraulic cylinder device 30 are integrally formed, and the cylinder case 31 is disposed in the vicinity of the vertical swing support portion of the front axle case 28.
[0017]
The front axle case 28 has a built-in gear device for driving the front wheels, and the front axle case 28 and the cylinder case 31 of the hydraulic cylinder device 30 are integrally formed by appropriate forming means such as a mold. Further, the cylinder case 31 is disposed above the vertical swing support portion of the front axle case 28.
[0018]
That is, the front axle case 28 is supported by a front bracket 32 at the front of the machine body and a rear bracket 34 at the rear so that the front axle case 28 can swing up and down around an axis in the longitudinal direction of the machine body. A bearing portion (vertical swing support portion) 28a having an axis line in the longitudinal direction of the body is formed at a substantially central portion in the axial direction extending to the left and right sides of the body of the front axle case 28. On the other hand, the front bracket 32 is formed with a center pin 32a that is rotatably fitted to the bearing portion 28a so as to protrude rearward of the machine body. The front bracket 32 is provided with support arms 32b and 32b extending substantially symmetrically and obliquely upward so as to suspend the center pin 32a around the center pin 32a. A fixed piece 32c is integrally attached to the distal end side of the support arm 32b.
[0019]
The front bracket 32 is fixed to a main frame (fixed frame) 36 constituting the traveling machine body 11 through the fixed pieces 32c and 32c. The main frame 36 extends forward from both the left and right sides of the engine 12, and the rear rear bracket 34 is attached to the lower part of the oil pan of the engine 12 via a mounting member 38 in the longitudinal direction of the fuselage. It is supported so that it can swing around the center.
[0020]
For this reason, the front axle case 28 is supported by the center pin 32a fitted to the bearing portion 28a so as to be swingable up and down around the axis in the longitudinal direction of the machine body. When the front wheel 16 travels on the uneven surface, the front axle case 28 can swing around the center pin 32a supported by the bearing portion 28a. By the action of the center pin 32a and the bearing portion 28a, there are advantages such that the impact force applied when the airframe is rapidly moved up and down is alleviated and that the left and right sides of the airframe are excessively inclined up and down.
[0021]
Further, according to the present embodiment, since the front axle case 28 and the cylinder case 31 are integrally formed, the shafts of both the piston rod 30a of the hydraulic cylinder device 30 and the front axle case 28 are formed as shown in FIG. Since the distance L between the center lines in the direction can be close, a predetermined front wheel steering angle can be obtained with a short stroke of the piston rod 30a.
[0022]
Further, in the present embodiment, the axial length of the cylinder case 31 is configured to be shorter than the facing lengths of the left and right fixed frames 36 and 36 extending forward from the left and right sides of the engine 12.
[0023]
That is, as shown in FIG. 3, when the cylinder case 31 integral with the front axle case 14 swings up and down so as to draw an arc with a radius centered on the center pin 32a, the left and right ends of the cylinder case 31 are The axial length of the cylinder case 31 is set to be shorter than the facing length of the fixed frames 36 and 36 so as not to interfere with the lower ends of the main frames 36 and 36. It should be noted that there is no problem if the axial length of the cylinder case 31 is shorter than the facing length of the fixed frames 36, 36, and as shown in the figure, even if they are on substantially the same line, the center pin 32a is What is necessary is that it does not interfere with each other when it swings up and down so as to draw an arc with a center radius.
[0024]
As described above, in the present embodiment, it is not necessary to consider the interference between the cylinder case 31 and the main frame 36. Therefore, it is not necessary to cut out a part of the main frame 36 in order to prevent interference, and the number of cut-out steps is reduced. Can be reduced.
[0025]
Incidentally, a kingpin case 40 and a final case 41 are respectively fixed to the outer end portions of the front axle case 28 in the axial direction, and the kingpin case 40 supports a king bin (not shown) extending substantially in the vertical direction. The king bin is connected to the wheel shaft 46 through a gear mechanism. A knuckle arm 42 is rotatably attached to the upper portion of the kingpin case 40. The knuckle arm 42 is connected to a piston rod 30 a described later via a joint 44.
[0026]
FIG. 5 is a diagram showing details of the hydraulic cylinder device 30, and a hydraulic port 37 connected to a hydraulic pump (not shown) and a hydraulic tank is provided at the left and right ends of the cylinder case 31. Plugs 39, 39 are fixed to the cylinder case 31 by bolts 43, 43 at the left and right outer ends of the cylinder case 31. The plug 39 is provided with O-rings 35, 35 on the inner diameter portion of the outer end portion, and a piston rod 30a is slidably fitted on the inner diameter side. Further, a piston 30b is fitted into a substantially central portion in the longitudinal direction of the piston rod 30a so as to be slidable on the inner diameter side of the cylinder case 31. An O-ring 35 'is attached to the outer diameter portion of the piston 30b.
[0027]
【The invention's effect】
According to the first aspect of the present invention, the front axle case and the cylinder case of the hydraulic cylinder device are integrally formed, and the cylinder case is disposed above the vertical swing support portion of the front axle case. The axle case is reinforced by the cylinder case, so that the mechanical strength of the front axle case can be increased, and the fastening portion etc. can be compared with the case where the front axle case and the cylinder case are formed separately and fixed with a fixture. The appearance can be made beautiful, the assembly man-hours can be reduced, and the material cost can be saved.
[0028]
In addition, according to the present invention, the cylinder case and the front axle case can be integrally formed so that the central axes of both can be brought close to each other. The front wheel steering angle can be obtained.
[0029]
According to the invention described in claim 2, since the axial length of the cylinder case is shorter than the facing length of the fixed frame extending forward from the left and right sides of the engine, the front axle case swings up and down. Even if it swings up and down around the support part, the cylinder case does not interfere with the fixed frame, so there is no need to cut out a part of the fixed frame to prevent interference, and it is possible to reduce the number of cut-out steps, The mechanical strength of the fixed frame can be maintained as it is.
[Brief description of the drawings]
FIG. 1 is an external perspective view of a tractor to which the present invention is applied.
FIG. 2 is a plan view of a front axle case and a hydraulic cylinder device.
FIG. 3 is a front view of the same.
FIG. 4 is a side view of the above.
FIG. 5 is a sectional front view of the hydraulic cylinder device.
FIG. 6 is a view showing a conventional example of a front wheel steering device in a tractor.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Tractor 11 Traveling machine body 28 Front axle case 28a Bearing part (vertical rocking | fluctuation support part)
30 Hydraulic cylinder device 30a Piston rod 30b Piston 31 Cylinder case 32 Front bracket 32a Center pin 32b Support arm 34 Rear bracket 36 Main frame (fixed frame)

Claims (2)

In the front wheel steering device for the vehicle along the front axle case, the hydraulic cylinder device for steering the front wheel power steering
The front axle case with integrally molded with the cylinder case of the hydraulic cylinder device, the front axle case a bearing portion formed before SL front axle case fitted rotatably to the center pin provided on the body side Is supported up and down swinging ,
A cylinder case formed integrally with the front axle case is disposed above the bearing portion.
A front wheel steering device for a vehicle. Both end portions of the front bracket having the center pin are attached to left and right fixed frames extending forward from the left and right sides of the engine, and the axial length of the cylinder case is determined from the facing length of the left and right fixed frames. Also made short,
The front wheel steering apparatus for a vehicle according to claim 1.

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