JP2006021719A - Steering device of working vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enable easy sharp turns of a vehicle by increasing a steering angle of a front wheel to improve efficiency of agricultural work. <P>SOLUTION: This steering device operates front wheels of a tractor provided at both left and right ends of a front axle housing 11. The front wheels 3, 3 are turned around king pins 14, 14 in the vertical direction by driving a first steering means (a cylinder for steering the front wheels) 15. A second steering means (a cylinder for steering the housing) 21 is provided on the front axle housing 11 to turn the housing 11 around a shaft core 13 (a joint 27) in an intermediate part by driving the second steering means. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a steering control device in a work vehicle such as an agricultural tractor or a rice transplanter.

Conventionally, a front axle housing having front wheels capable of changing the steering angle at both left and right ends is pivotally supported around a vertical axis set at the intermediate portion, and the front axle housing is rotated by a steering handle. A technique is known in which yawing is performed back and forth in conjunction with a dynamic operation (see, for example, Patent Document 1).
JP 11-321693

  In the above-mentioned conventional one, the steering axis is set on the center line of the axle, so that there is a problem that the turning radius becomes relatively large and sufficient turning cannot be performed. An object of the present invention is to increase the working angle by increasing the front wheel turning angle so that a small turning of the vehicle can be sufficiently exerted.

In order to solve the above problems, the present invention has taken the following technical means.
That is, the present invention according to claim 1 is a steering device for the front wheel (3) provided at the left and right ends of the front axle housing (11), wherein the front wheel (3) rotates the steering handle (7). The first steering means (15) linked to the operation is pivotally supported around the king pin (14) in the vertical direction so that the steering angle can be freely changed. The front axle housing (11) is supported by the steering handle (7). By driving the second steering means (22) interlocking with the pivoting operation, the vertical direction set in the middle portion of the housing (11) is deviated backward by a predetermined distance from the center line of the axle (11a). A steering device for a work vehicle is provided that is pivotally supported around an axis (13).
(Function)
By rotating the steering handle 7, the left and right front wheels (3) can be steered around the kingpin (14) via the tie rods, knuckle arms and the like via the first steering means (15). Further, when the steering handle (7) is turned, the front steering housing (11) is swung back and forth about the vertical axis (13) behind the intermediate portion by the operation of the second steering means (22). The left and right front wheels (3, 3) can be steered. The center of rotation of the front axle housing (11) is set at a position spaced a predetermined distance behind the center line of the axle, so that the front wheel turning angle is greatly increased compared to that set on the axle and turning. The radius can be reduced and work efficiency is improved.

  In short, according to the present invention, the first steering means (15) and the second steering means (22) facilitate the turning operation of the vehicle. In particular, the second steering means (22 ), The steering pivot center of the front axle housing (11) is set at a position separated by a predetermined distance from the axle (11a) line, so that the vehicle can be turned more slightly than the conventional one, and Also, the turning can be performed smoothly, and the roughness of the headland can be reduced and the work efficiency can be improved.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A mode in which the present invention is provided in a riding tractor that is an example of a work vehicle will be described below with reference to the drawings.
FIG. 1 shows an overall side view of the tractor. An engine E is mounted on the front portion of the tractor vehicle body 1 and the rotational power of the engine E is transmitted to a transmission in the transmission case 2. The reduced rotational power is transmitted to the left and right front wheels 3 and the left and right rear wheels 4. A rotary working machine R is mounted on the rear portion of the vehicle body 1 and is moved up and down by the vertical movement of the lift arm 5. Reference numeral 6 denotes a cockpit, and 7 denotes a steering handle for steering the left and right front wheels 3 and 3 described later.

  A front axle bracket 12 that supports a front axle housing 11 is supported on an engine bracket 10 equipped with the engine E so as to be swingable back and forth around a vertical axis (hereinafter referred to as a steering shaft 13). Yes. The front wheels 3, 3 at the left and right ends of the front axle housing 11 are supported by the steering housing 19 so that the steering angle can be freely changed around the king pins 14, 14 in the vertical direction with respect to the front housing 11. In conjunction with the dynamic operation, the first steering means (hereinafter, front wheel steering cylinder 15) is telescopically operated so as to steer through the tie rod 17, the knuckle arm 18 and the like. The front wheel steering cylinder 15 is composed of a double-acting hydraulic cylinder, and this hydraulic cylinder is provided with a front wheel turning angle detection stroke sensor 16 for detecting the cylinder expansion / contraction length. Is measured to control the turning angle of the steering housing.

  The front axle housing 11 has a center pivot shaft 23 at the center, and is supported by a pivot bearing metal 24 integral with the front axle bracket 12. The differential case 25 at the center of the front axle housing 11 is provided with a front differential gear mechanism. The front differential gear mechanism is connected to the axle 3a of the left and right front wheels 3 and 3 via the left and right front differential axles 11a. It is configured to do. The input to the front differential gear mechanism is configured to be input from the rear transmission case 2 via the front wheel transmission shaft 26 and the universal joint 27.

  The steering shaft 13 for swinging the front axle housing 11 back and forth is on the front differential axle 11a axis, that is, at a position away from the axial center line of the axle 11a by a predetermined distance rearward. Are set on the same axis. The front axle bracket 12 that swings around the steering shaft 13 is a bearing spherical housing 28 that bears and surrounds the front portion of the joint 27 as a rear portion thereof, and a bearing that surrounds and surrounds the rear portion of the joint 27. The spherical housing 29 is configured to swing and rotate with the joint 27 refractive axis and the steering shaft 13 center being concentric. The front wheel transmission shaft 26 is mounted in a transmission case 30.

  Between the front axle housing 11 and the engine bracket 10, second steering means (hereinafter referred to as a housing steering cylinder 21) composed of a hydraulic cylinder that expands and contracts by hydraulic pressure is provided, and the steering handle 7 can be rotated. By operating the housing steering cylinder 21 in conjunction with each other, the front axle housing 11 is swung back and forth around the steering shaft 13 via the front axle bracket 12 to steer the left and right front wheels 3 and 3. can do. The housing steering cylinder 21 is provided with an axle cutting angle detection stroke sensor 22 for detecting the expansion / contraction length of the cylinder so as to control the cutting angle of the axle by measuring the expansion / contraction length of the hydraulic cylinder. It is configured.

  The vehicle turning control in conjunction with the turning operation of the steering handle includes a control method in which the steering housing is steered around the kingpin and the axle housing is simultaneously steered, and a control method in which the axle housing is steered after steering the steering housing. Conceivable. In the case of this example, any method may be adopted, but rather the latter allows more stable control.

  Further, as the restraint control in front axle steering, as shown in FIG. 4, when the auxiliary transmission lever 36 provided on the input side of the controller 35 is switched to the high speed side, the control valve solenoid 21a of the housing steering cylinder 21 is switched. As a configuration in which the axle steering is cut so as not to operate, safety is improved. A steering angle sensor 37 of the steering handle 7 and a stroke sensor 22 of the housing steering cylinder 21 are connected to the input side of the controller 35. When the steering handle 7 is turned more than a predetermined angle, the housing steering cylinder 21 is actuated via the control valve solenoid 21a according to the detection result of the steering angle sensor 37, and the axle angle detection value set by the stroke sensor 22 is set. Turn based on. When the auxiliary transmission is switched to the high speed side by the auxiliary transmission lever 36, the axle steering is cut even if the steering handle 7 is turned. is there.

Next, based on FIG. 5 thru | or FIG. 7, the structure of the backup device which raises the working machine R at the time of reverse | reversing of an airframe is demonstrated.
The backup motor 41 is disposed immediately below the bracket 43 that supports the hydraulic lift lever 42, and a rod 45 is passed through a hole 44 that passes through the bracket 43, and the hydraulic lift lever 42 is operated by pushing and pulling the rod 45. The structure which interlockedly connected as shown is shown. That is, the hydraulic elevating lever 42 protrudes upward from the fender 46, and when the swing operation is performed forward, the work implement is lowered, and when the swing operation is performed backward, the work implement is raised. When the transmission is operated to the reverse position, the backup motor 41 is operated by turning on the reverse detection switch, and the rod 45 is pulled to automatically operate the hydraulic lift lever 42 in the upward direction. When the backup motor is housed in the fender 46, providing a hole for passing a rod in the fender itself as in the prior art has a problem that the productivity of the fender is deteriorated and the appearance is also impaired. In this example, by placing the motor in the bracket for supporting the hydraulic lift lever, such a problem can be solved, so that mudguards can be easily taken.

Next, a mudguard cover provided in the safety frame will be described with reference to FIG.
A safety frame 50 is erected on the back of the cockpit 6, and a sun visor 51 is provided above the cockpit so as to project forward from the upper end of the safety frame 50. In this example, an acrylic plate-like mudguard cover 52 is detachably provided in the inner space of the safety frame 50, and mud scattering is particularly severe during scuffing work with water on the field. Need a mudguard cover. At this time, as shown in the figure, a mudguard cover 52 is attached to the back of the safety frame 50 via a resin detachable rivet 53 so as to prevent mud from scattering to the operator. And since a mudguard cover is unnecessary in normal tillage work (rather, it is more visible and easier to work with), in this case, the mudguard cover is stored in the upper sun visor.

A side view of a tractor. The side view of a principal part same as the above. The top view of a principal part same as the above. Control block diagram. The side view of the principal part of a backup apparatus. The top view of a principal part same as the above. The perspective view of a principal part same as the above. The perspective view of a safety frame and a sun visor part.

Explanation of symbols

E Engine 1 Tractor body 2 Mission case 3 Front wheel 4 Rear wheel 7 Steering handle 10 Engine bracket 11 Front axle housing 12 Front axle bracket 13 Vertical axis (steering axis)
14 Kingpin 15 Front wheel steering cylinder 15 (first steering means)
17 Tie rod 18 Knuckle arm 21 Housing steering cylinder (second steering means)
23 Center pivot shaft 24 Pivot shaft metal 27 Universal joint 28 Bearing spherical housing 29 Bearing spherical housing

Claims (1)

  A steering device for the front wheels (3) provided at the left and right ends of the front axle housing (11), wherein the front wheels (3) are first steering means (15) interlocking with the turning operation of the steering handle (7). ) Is pivotally supported around the vertical kingpin (14) so that the steering angle can be freely changed, and the front axle housing (11) is coupled to the steering operation of the steering handle (7). By driving the means (22), it can be rotated around a vertical axis (13) set at a middle position of the housing (11) and deviated by a predetermined distance from the center line of the axle (11a). A steering device for a work vehicle characterized by being pivotally supported.

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