JPH061464Y2 - Turning mechanism in front-wheel steering vehicle - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Use The present invention relates to a turning mechanism in a front-wheel steering vehicle.

(B) Conventional Technology Conventionally, turning mechanisms for various types of front-wheel steering vehicles have been developed for the purpose of improving workability in a field of a tractor or the like, and particularly reducing the turning radius at the time of turning. As one form of such a turning mechanism, there is a front wheel inner / outer wheel actuation type.

(C) Problems to be solved by the invention However, the conventional front-wheel inner-outer-wheel actuated drive type turning mechanism has the following problems.

That is, since the speed-up switching mechanism is provided between the transmission and the front wheel drive shaft, the front wheel drive shaft and the joint mechanism are also speeded up, which causes considerable noise and vibration.

An object of the present invention is to provide a turning mechanism in a front wheel steering vehicle that can solve the above problems.

(D) Means for Solving the Problems The present invention provides a mission case having a built-in transmission that is connected to an engine at the rear of the machine body, and extends the front wheel drive shaft forward from the mission case. A front-wheel steering vehicle characterized in that a gear-shift type speed-increasing switching mechanism is interposed between a front end of the front-wheel drive shaft and a front-wheel differential device provided at a substantially central portion of a front axle case having front wheels attached to both ends. It relates to the turning mechanism in.

(E) Operation and Effect With the above-described configuration, the present invention has the following operation and effect.

Since the speed increase switching mechanism is located in front of the front wheel drive shaft, the rotation of the joint between the front wheel drive shaft and the speed increase switching mechanism is not accelerated, and noise and vibration can be reduced.

Since the speed increasing / switching mechanism is a gear shift type, the structure is simple, the manufacturing can be performed at low cost, and the maintenance is easy.

Since the speed increasing / switching mechanism is a gear shift type, the interlocking with the steering mechanism becomes smooth.

(F) Embodiment Hereinafter, the present invention will be specifically described based on an embodiment shown in the accompanying drawings.

In FIG. 1, A is a tractor, and the tractor A has a front wheel 1 and a rear wheel 2 attached to its front and rear portions, respectively, and both the front wheel 1 and the rear wheel 2 will be described below. It is driven by a drive mechanism.

That is, in the drive system diagram shown in FIG. 2, 3 is an engine, 4 is a main clutch, 5 is a main transmission, 6 is an auxiliary transmission, and 7 is a rear wheel differential device. Is linked to each rear wheel 2 via a final reduction gear 9. Reference numeral 10 is a rear wheel brake provided on the outer end of each differential yoke shaft 8.

In the above structure, the main transmission device 5 and the auxiliary transmission device 6
Are incorporated in the mission case M.

A front wheel drive system 11 includes a front wheel drive shaft 14 connected to the auxiliary transmission 6 through a gear train 12 and a universal joint 13, and a front wheel differential device 15 connected to the front wheel drive shaft 14. Each differential yoke shaft 16 of the differential device 15 is connected to the front wheel 1 via a gear train 17, and the front wheel 1 is steerable around a kingpin.

The present invention is characterized in that, in the front wheel drive system 11, a gear shift type speed-increasing switching mechanism B is provided between the front wheel drive shaft 14 and the front wheel differential device 15.

With reference to FIG. 3, the structure of the gear shift type speed increasing / switching mechanism B will be described in detail.

In the figure, reference numeral 20 denotes a front axle case which incorporates a front wheel differential device 15 and is swingably supported left and right on a body S (see FIG. 1) by a case swing support portion (not shown). A rear end of the axle case 20 is provided with a base end of a cylindrical casing 21 extending rearward.

Although not shown, the tubular casing 21 is arranged so as not to come into contact with an oil pan or a clutch housing provided at the bottom of the machine body S.

Further, the tubular casing 21 has a pinion shaft 23, which has a bevel gear 22 meshing with a gear train of the front wheel differential device 15 at a front end thereof, from the front wheel differential device 15 toward the front wheel drive shaft 14, and a rear end thereof. A speed increasing / switching mechanism input shaft 24 is connected in parallel with the front wheel drive shaft 14 by a universal joint 13.

Further, reference numerals 25 and 26 are an output side small gear and an output side large gear, which are attached to the pinion shaft 23 so as to be rotatable relative to each other with a space therebetween in the axial direction.

A multi-disc clutch 27 and a cam sliding body 28 are provided between the gears 25 and 26, and the outer disc of the multi-disc clutch 27 is integrally connected to the output side small gear 25. In addition, the inner disc is integrally connected to the pinion shaft 23.

Further, the cam slide body 28 is attached to the pinion shaft 23 so as to rotate integrally with the pinion shaft 23 by spline fitting so that the cam slide body 28 is movable in the axial direction. A dog clutch 29 provided on the corresponding side surface of 26 is detachably engaged with a dog clutch 30.

With this configuration, during normal traveling, as shown in FIG.
Since the cam sliding body 28 is located on the right side and the multi-disc clutch 27 is not pressed by the cam sliding body 28, the power transmission from the output side small gear 25 to the pinion shaft 23 via the multi-disc clutch 27. Even if the output side small gear 25 rotates, the pinion shaft 23 does not rotate. But in this state,
The dog clutch 30 is constantly meshed with the dog clutch 29, and the meshing of the output side large gear 26 causes the dog clutch 30 to mesh with the dog clutch 29.
The pinion shaft 23 is integrally connected via 29 and 30, and when the output shaft large gear 26 rotates, the pinion shaft 23 also integrally rotates.

On the other hand, when increasing the speed, in FIG. 3, when the cam slide body 28 is moved to the left side and the multi-plate clutch 27 is pressed, the output side small gear 25 and the pinion shaft 23 are integrally connected via the multi-plate clutch 27. As a result, the pinion shaft 23, on which the output side small gear 25 rotates, also integrally rotates both. But,
On the contrary, the dog clutch 30 is disengaged from the dog clutch 29, and the pinion shaft 23 does not rotate even if the output side large gear 26 rotates.

The sliding cam body 28 is moved in the axial direction by a swing fork 32 pivotally supported by a pivot 31. The swing fork 32 is a steering mechanism D (see FIG. 1).
The multi-plate clutch 27 can be pressed / released and the dog clutches 29, 30 can be engaged / disengaged in conjunction with the steering operation of the steering mechanism D.

Further, in the tubular casing 21, 33 and 34 are fixed to the speed-increasing switching mechanism input shaft 24 with a space in the axial direction, and the input side large gear and the input side small gear rotate integrally with the input shaft 24. The gears 33 and 34 are always meshed with the output side small gear 25 and the output side large gear 26, respectively.

In FIG. 3, 35, 36, 37 and 38 are pinion shafts 23.
And a speed-up switching mechanism input shaft 24 is a bearing for rotatably supporting the tubular casing 21.

Next, the operation of the gear shift type speed increasing / switching mechanism B having the above configuration will be described.

When the engine 3 is started and the main clutch 4 is connected, the power of the engine 3 passes through the main clutch 4, the main transmission device 5, the auxiliary transmission device 6, the rear wheel differential device 7 and the final reduction gear device 9 to the rear wheels 2 respectively. Transmitted to.

On the other hand, since it is transmitted from the auxiliary transmission 6 to each front wheel 1 via the front wheel drive shaft 14, the gear-shift type speed increase switching mechanism B, and the front wheel differential device 15, the tractor A has four front wheels 1 and two rear wheels 2. The wheels will drive as driving wheels.

Then, when traveling straight ahead, the front wheels 1 and the rear wheels 2 are driven at the same speed. This will be described below with reference to the drive system explanatory diagram.

That is, during straight running, the sliding cam 28 is located on the left side on the pinion shaft 23, and the output side large gear 26 and the pinion shaft 23 are integrally connected by the dog clutches 29 and 30 which are constantly meshed. Further, since the steering mechanism D cannot operate the sliding cam body 28 unless the cutting angle of the front wheels 1 exceeds a certain value, the multi-disc clutch 37 is in the released state, and the output side small The gear 25 and the pinion shaft 23 are in a relationship of freely rotating with each other.

For this reason, the rotation of the front wheel drive shaft 14 depends on the speed increase switching mechanism input shaft.
It is transmitted from 24 to the pinion shaft 23 via the input side small gear 34, the output side large gear 26, and the dog clutches 29 and 30, and thereafter,
It is transmitted to the front wheel 1 via the front wheel differential device 15 and the front wheel yoke shaft 16.

On the other hand, at the time of increasing the speed, when the steering angle of the front wheel 1 becomes a certain value or more by the operation of the steering mechanism D, the swing hawk 32 moves the cam sliding body 28 to the left on the pinion shaft 23 to move the multiple disc clutch 27.
Is brought into a pressed state, whereby the output side small gear 25 and the pinion shaft 23 are integrally connected. On the other hand, since the dog clutches 29 and 30 are disengaged, the output side large gear 2
The 6 and the pinion shaft 23 are in a relationship of being freely rotatable with respect to each other.

For this reason, the rotation of the front wheel drive shaft 14 depends on the speed increase switching mechanism input shaft.
24 to input large gear 33, output small gear 25, multi-plate clutch
It is transmitted to the pinion shaft 23 via 27 and then transmitted to the front wheel 1 via the front wheel differential device 15 and the front wheel yoke shaft 16.

Then, in the transmission of the rotational force, the relationship of the number of teeth between the input side large gear 33 and the output side small gear 25 at the time of acceleration is the same as that between the input side small gear 34 and the output side large gear 26 during straight traveling. Since it is just the opposite of the numerical relationship, front wheels 1 compared to when traveling straight ahead
The number of revolutions, that is, the speed can be significantly increased.

Therefore, the tractor A can turn at a small turning radius without slipping.

Further, in front of the front wheel drive shaft 14, there is a gear shift type speed-increasing switching mechanism B.
Is located, the rotation of the universal joint 13 between the front-wheel drive shaft 14 and the speed-increasing switching mechanism B is not increased, and noise and vibration can be reduced.

Further, as other effects obtained by the above embodiment, the following are fried.

Since the gear-shift type speed-increasing switching mechanism B is provided in the front, the weight balance between the front and rear becomes good, and the center of turning comes closer to the front than in the past, so that the turning radius can be reduced.

Since the speed-increasing switching mechanism B is a gear shift type, the structure is simple, the cost can be reduced, the maintenance is easy, and the linkage with the steering mechanism D is smooth.

Except for the gear-shift type speed-increasing switching mechanism B, the other components are of standard specifications, so that a swinging mechanism capable of small swinging can be configured easily and inexpensively, and retrofitting (option) is also easy.

[Brief description of drawings]

FIG. 1 is a side view of a front wheel steering vehicle including a turning mechanism according to the present invention, FIG. 2 is a drive system diagram, and FIG. 3 is an enlarged structural explanatory view of the turning mechanism. In the figure, A: tractor B: gear change type speed increasing switching mechanism D: steering mechanism M: mission case S: airframe 1: front wheel 14: front wheel drive shaft 15: front wheel differential device 20: front axle case 23: pinion shaft 24: Input shaft for speed-up switching mechanism 25: Output side small gear 26: Output side large gear 27: Multi-plate clutch 28: Sliding cam body 33: Input side large gear 34: Input side small gear

Claims (1)

[Scope of utility model registration request] 1. A transmission case (M) containing a transmission connected to an engine (3) is arranged at the rear of the body (S), and the front wheel drive shaft (14) extends forward from the transmission case (M). ) Is extended to the front end of the front wheel drive shaft (14) and the front wheels (1),
A front wheel steering characterized in that a gear-shift type speed-increasing switching mechanism (B) is provided between the front axle case (20) to which (1) is attached and a front wheel differential device (15) provided substantially in the center of the front axle case (20). A turning mechanism in a vehicle.