JP2821873B2 - Front-wheel steering vehicle equipped with speed-up switching mechanism - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a turning mechanism in a front-wheel steering vehicle. 2. Description of the Related Art Conventionally, an operation mechanism for operating a speed-increasing switching mechanism has been provided in order to improve workability of a tractor or the like in a field, particularly to reduce a turning radius when turning. Provided on the knuckle arm located at the center of the differential shaft, when the knuckle arm has become a certain rotation angle or more in conjunction with the steering operation of the steering wheel, actuate the speed increase switching mechanism via the operating mechanism, A front-wheel steering vehicle capable of providing a desired speed increase to the front wheels has been developed. [0003] However, in such a conventional front-wheel steering vehicle, when the knuckle arm becomes a certain rotation angle or more in conjunction with the steering operation of the steering wheel, the front wheels are stepped. As a result, the vehicle may make a sharp turn at an unexpectedly high speed of the operator, giving a fear to the operator or causing a fall accident. Therefore, in the present invention, a speed increasing differential mechanism is interposed between the transmission and the front wheel differential device, and is an input portion of the speed increasing differential mechanism. The rotating housing is interlocked with the transmission, the pinion shaft as one output of the speed increasing differential mechanism is interlocked with the front wheel differential, and the intermediate rotating cylinder as the other output is attached to the pinion shaft. A dog clutch, and a multi-plate clutch capable of decelerating or stopping the rotation of the intermediate rotary cylinder, selectively interlockingly connected via a switching member, and a speed increasing differential mechanism, a multi-plate clutch, and a dog clutch. Is provided in a cylindrical casing, and a steering mechanism is interlockingly connected to the multi-plate clutch and the dog clutch via a switching member. Things. [0005] The present invention is also characterized in that the speed increasing differential mechanism, the multi-plate clutch and the dog clutch are coaxially arranged in a cylindrical casing having substantially the same diameter. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view showing a first embodiment of the present invention. In FIG. 1, A is a tractor, and the tractor A has a front wheel 1 and a rear wheel 2 mounted on its front and rear portions, respectively. The front wheel 1 and the rear wheel 2 are both described below. Driven by a driving mechanism. That is, in the drive system diagram shown in FIG.
Is an engine, 4 is a main clutch, 5 is a main transmission, 6 is an auxiliary transmission, 7 is a rear wheel differential device, and a differential yoke shaft 8 of the differential device 7 is connected to each rear wheel 2 via a final reduction gear 9. Linked and linked. Reference numeral 10 denotes a rear wheel brake provided at the outer end of each differential yoke shaft 8. In the above configuration, the main transmission 5,
The auxiliary transmission 6 is built in the transmission case. Reference numeral 11 denotes a front wheel drive system. The front wheel drive system 11 is connected to a front wheel drive shaft 14 connected to the auxiliary transmission 6 via a gear 12 and a universal joint 13, and is connected to the front wheel drive shaft 14. The front yoke shaft 16 of the front wheel differential device 15 is connected to the front wheel 1 via a gear train 17.
The front wheel 1 can be steered around the kingpin. According to the present invention, in the front wheel drive system 11, a speed increasing switching mechanism B is provided between a front wheel drive shaft 14 and a front wheel differential device 15.
Is provided. Referring to FIG. 3, the structure of the speed-increasing switching mechanism B will be described in detail. Referring to FIG. 1, reference numeral 21 denotes a front axle case which incorporates a front wheel differential device 15 and is supported by a case swing support portion 21a so as to be able to swing left and right. The base end of the cylindrical casing 20 that extends rearward and is formed to have substantially the same diameter is protruded,
The tubular casing 20 is supported at an intermediate portion thereof by a bearing 24 having an upper end fixed to a machine frame 22. Reference numerals 25 and 26 denote an oil pan and a scratch housing provided at the bottom of the machine casing 22, and the tubular casing 20 is disposed so as not to come into contact with them. The cylindrical casing 20 has a pinion shaft 29 having a bevel gear 27 at its front end, which meshes with a gear train of the front wheel differential device 15, from the front wheel differential device 15 toward the front wheel drive shaft 14. The rear end is arranged in series with a speed-increasing switching mechanism input shaft 30 operatively connected to the front wheel drive shaft 14 by a universal joint 13. Reference numeral 31 denotes an intermediate rotary cylinder mounted concentrically and relatively rotatably over substantially the entire length of the pinion shaft 29. The intermediate rotary cylinder 31 is slidable in the axial direction at its front end, but is splined. A sliding cam body 32 that rotates integrally with the intermediate rotary cylinder 31 is mounted, and the sliding cam body 32 is detachably engaged with a flange 34 fixed to a middle of a pinion shaft 29 via a dog clutch 33. ing. The sliding cam body 32 is moved in the axial direction by a swinging fork 36 serving as a switching member pivotally supported by a pivot 35. The swinging fork 36 is shown in the drawing. The dog clutch 33 can be engaged and disengaged by being linked to a steering mechanism that does not operate. Reference numeral 37 denotes a middle part of the intermediate rotary cylinder 31;
The multi-plate clutch 37 is mounted at a position adjacent to the sliding cam body 32. The multi-plate clutch 37 compresses a spring 38 by moving the sliding cam body 32 in the axial direction, thereby moving the intermediate rotating cylinder 31 into a cylinder. It can be fixed to the tubular casing 20 and its rotation can be stopped. Reference numeral 40 denotes a speed increasing differential mechanism provided at the rear end of the pinion shaft 29. The differential mechanism 40 has a rotary housing 41 mounted concentrically around the rear end of the pinion shaft 29. A bevel gear 4 having an axis in a direction orthogonal to the axis of the pinion shaft 29 is attached to the inner surface of the pinion shaft 29, and the front and rear surfaces of the bevel gear 42 are fixed to the rear end of the pinion shaft 29, respectively. The rear end of the rotary housing 41 is meshed with a bevel gear 44 integrally formed with the rear end. It is constituted by doing. Next, the speed increasing switching mechanism B having the above configuration
The operation of will be described. When the engine 3 is started and the main clutch 4 is connected, the power of the engine 3 is transmitted via the main clutch 4, the main transmission 5, the auxiliary transmission 6, the rear wheel differential 7 and the final reduction gear 9. The power is transmitted to the rear wheel 2. On the other hand, the power is transmitted from the auxiliary transmission 6 to the front wheels 1 via the front wheel drive shaft 14, the speed increasing switching mechanism B, and the front wheel differential device 15, so that the tractor A The vehicle travels using the wheels as drive wheels. When the vehicle is traveling straight, the front wheel 1 and the rear wheel 2 are driven at the same speed. This will be described below with reference to a drive system explanatory diagram. That is, since the steering mechanism is not steered to the extent that the swinging fork 36 is actuated, the multi-plate clutch 37 is not actuated, and the intermediate rotary cylinder 31 is not fixed to the cylindrical casing 20. On the other hand, the intermediate rotary cylinder 31 is integrally connected to the pinion shaft 29 by the dog clutch 33. For this reason, the rotation of the front wheel drive shaft 14 is transmitted from the speed increasing switching mechanism input shaft 30 to the rotary housing 41.
The bevel gear 42, the bevel gear 43, the pinion shaft 29, the bevel gear 44, and the intermediate rotary cylinder 31 rotate at the same speed as the front wheel drive shaft 14, and are thereafter transmitted to the front wheel 1 via the front wheel differential device 15 and the front wheel yoke shaft 16. Will be. On the other hand, when the steering mechanism is operated to the extent that the swinging fork 36 is operated, the multi-plate clutch 37 is operated, and the intermediate rotary cylinder 31 is fixed to the cylindrical casing 20 and the dog clutch With the release of 33, the pinion shaft 29
And the connection with the intermediate rotary cylinder 31 is released. Therefore, the rotation of the front wheel drive shaft 14 is transmitted from the speed increasing switching mechanism input shaft 30 to the rotary housing 41.
Only the transmission path of the bevel gear 42 → the bevel gear 43 → the pinion shaft 29 → the front axle case 21 is active, and this and the relative rotation with the rotary housing 41 form an operating gear mechanism, and the pinion shaft 29 is connected to the front wheel drive shaft 14. , And then rotate the front wheel differential device 15 and the front wheel yoke shaft
The power is transmitted to the front wheel 1 via 16. Accordingly, the tractor A can turn with a small turning radius without causing a slip. In the above configuration, the speed increasing switching mechanism B
Except for the other components, which are standard specifications, a swing mechanism capable of small swing can be easily and inexpensively constructed, and retrofitting (optional) becomes easy. Also, front axle case
Since the speed-increasing switching mechanism B is disposed at the rear of the vehicle, an extra transmission unit can be dispensed with, which does not hinder traveling. Furthermore, since the speed increase switching mechanism B is provided in the front, the front-rear weight balance is improved, and the turning center is located forward, so that the turning radius can be reduced. According to the first aspect of the present invention, a speed increasing differential mechanism is provided between the transmission and the front wheel differential,
The rotary housing, which is the input unit of the speed increasing differential mechanism, is interlocked with the transmission, the pinion shaft, which is one output unit of the speed increasing differential mechanism, is interlocked with the front wheel differential device, and the other output unit. A dog clutch in which a certain intermediate rotary cylinder is mounted on the pinion shaft, and a multi-plate clutch capable of reducing or stopping the rotation of the intermediate rotary cylinder are selectively interlocked with each other via a switching member. Since the differential device, the multi-plate clutch and the dog clutch are disposed in the cylindrical casing, and the steering mechanism is interlocked to the multi-plate clutch and the dog clutch via a switching member, the angle of the front wheel exceeds the set angle. In conjunction with the steering operation, the dog clutch is disengaged to disengage the pinion shaft from the intermediate rotary cylinder, and the multiple disc clutch is connected to reduce or stop the rotation of the intermediate rotary cylinder. By, The speed increasing ratio of the front-wheel drive in accordance with the steering amount of the steering mechanism steplessly, and gradually can be increased, it is possible to pivot the body smoothly. Accordingly, it is possible to prevent the operator from feeling terrified or causing a fall accident. Further, since the speed increasing differential mechanism, the multi-plate clutch and the dog clutch are disposed in the cylindrical casing, the speed increasing differential mechanism, the multi-plate clutch and the dog clutch are provided in the cylindrical casing. With the clutch incorporated, it can be mounted or removed between the transmission and the front wheel differential device, which facilitates assembly and maintenance operations. Further, the cylindrical casing in which the speed increasing differential mechanism, the multi-plate clutch and the dog clutch are disposed inside,
It can also function as a front weight acting on the front part of the fuselage, so that the front-rear weight balance of the fuselage can be improved and steering operability can be improved without separately attaching a front weight. According to the second aspect of the present invention, since the speed increasing differential mechanism, the multi-plate clutch and the dog clutch are coaxially arranged in the cylindrical casing having substantially the same diameter. By making the cylindrical casing a small diameter and compact shape, it is possible to sufficiently secure the ground height of the cylindrical casing. In addition, it is possible to prevent the cylindrical casing from colliding with the ridge, and the present machine can be applied to various operations.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side view of a front-wheel steering vehicle (tractor) provided with a turning mechanism according to the present invention. FIG. 2 is a diagram of the drive system. FIG. 3 is an explanatory view of an enlarged structure of a turning mechanism. [Description of Signs] A Tractor B Speed-up switching mechanism 14 Front wheel drive shaft 21 Front axle case 21a Swing support

Claims (1)

(57) [Claims] A speed increasing differential mechanism (40) is interposed between the transmission and the front wheel differential device (15), and the rotary housing (41), which is an input part of the speed increasing differential mechanism (40), is connected to the transmission. The pinion shaft (29), which is one output unit of the speed increasing differential mechanism (40), is linked to the front wheel differential device (15), and the intermediate rotary cylinder (31), which is the other output unit, is linked. A dog clutch (33) attached to the pinion shaft (29) and a multi-plate clutch (37) capable of reducing or stopping the rotation of the intermediate rotary cylinder (31) through a switching member. In addition to the interlocking connection, the speed increasing differential mechanism (40), the multi-plate clutch (37) and the dog clutch (33) are connected to the cylindrical casing (2
0), the above-mentioned multi-plate clutch (37) and dog clutch
(33) A front-wheel steering vehicle equipped with a speed-increasing switching mechanism, wherein a steering mechanism is interlocked and connected via a switching member. 2. A cylindrical casing (20) in which a speed increasing differential mechanism (40), a multi-plate clutch (37), and a dog clutch (33) are formed to have substantially the same diameter.
A front-wheel steering vehicle equipped with the speed-increasing switching mechanism according to claim 1, wherein the vehicle is coaxially arranged.