JPH05193390A - Wheel drive for tractor - Google Patents

Abstract

(57) [Abstract] [Purpose] In a full-time four-wheel drive type tractor that constantly drives the front wheels 7 when the front wheels 7 are lifted and the full-time four-wheel drive or brakes cannot be activated. , Forcibly lock the full-time four-wheel drive by emergency operation to improve safety. [Structure] A full-time four-wheel drive tractor structure in which front and rear wheels 7, 3 are automatically switched to four-wheel drive 4WD by slipping of front wheels 7 by two-wheel drive 2WD. There is provided a four-wheel drive interlocking device 2 for forcibly switching from the two-wheel drive 2WD to the four-wheel drive 4WD by stepping on the brake petal 25 that brakes the left and right front wheels 7.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wheel drive device for a tractor, and in a tractor having a front wheel as a drive wheel in a two-wheel drive traveling mode 2WD, the front wheel is automatically slipped by slipping the front wheel. In the full-time four-wheel drive in which the drive mode is switched to the four-wheel drive traveling mode 4WD, the front wheels on the left and right are braked to forcibly switch to the four-wheel drive 4WD.

[0002]

2. Description of the Related Art In a tractor in which front wheels are always driven to achieve full-time four-wheel drive 4WD, for example, a mower is mounted on the front side of a vehicle body and a rear side is mounted on the rear side. When a heavy object is mounted on a vehicle and descends backwards on a steep slope, the center of gravity is applied to the rear wheels, the front wheels are lifted, and full-time four-wheel drive and brakes do not work. It may happen. In such a case, the brake will still be pressed as the operation of the moment, so the present invention intends for safe driving by forcibly locking the full-time four-wheel drive by pressing the brake. is there.

[0003]

This invention is a two-wheel drive 2
In full-time four-wheel drive in which front / rear wheels 7, 3 are automatically switched to four-wheel drive 4WD by slipping front wheels 7 by WD, by stepping on brake petal 25 that brakes both front wheels 7 on the left and right, A wheel drive device for a tractor is provided with a four-wheel drive interlocking device 2 for forcibly switching from two-wheel drive 2WD to four-wheel drive 4WD.

[0004]

When the front wheel 7 becomes larger than the rotation of the rear wheel 3 due to slippage or the like while the vehicle is traveling by the two-wheel drive 2WD of the front wheel 7, the full-time four-wheel drive causes the two wheels of the front wheel 1 to rotate. The drive 2WD is automatically switched to the four-wheel drive 4WD that also drives the rear wheels 3. or,
On the contrary, if the rotation of the rear wheels 3 is larger than the driving rotation of the front wheels 7 during traveling of the four-wheel drive 4WD, the two-wheel drive 2WD
Is automatically switched to.

When the brake petal 25 is stepped on, the brakes act on the left and right front wheels 1 to stop traveling. By stepping on the brake 25, the four-wheel drive interlocking device 2 is interlocked, and even in the two-wheel drive 2WD state, this is forcibly switched to the four-wheel drive 4WD,
This four-wheel drive 4WD is maintained and fixed. In this manner, the brake petal 25 is stepped on to brake the front wheels 7 on the drive side at all times to stop the traveling, and the full-time four-wheel drive is forcibly driven even by the two-wheel drive 2WD. Since the vehicle is switched to the four-wheel drive 4WD by 2 and is maintained and fixed, even if the front wheels 7 are easily lifted up as described at the beginning, simply step on the brake petal 25 as the operation of the moment. Then, brake and forced four-wheel drive 4
By switching to WD, safe driving can be performed with quick and accurate operation.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In the tractor shown in the drawing, the front wheels 7 are driven in a two-wheel drive mode, and a full-time four-wheel drive device 62 is provided in the transmission system on the rear wheel 3 side. In addition, steering is performed on the rear wheel 3 side. The tractor vehicle body 1 includes an engine E and a crankshaft 10 of the engine E from a rear portion to a front portion.
A clutch housing 14 that houses a main clutch 13 that is interlocked with a drive shaft 11 that is connected to the drive shaft and a power take-off shaft (PTO shaft) 12, and traveling shafts 15 and 1 extending from the drive shaft 11 to the front.
6 and PTO shaft 12 and the like interlocking shaft housing 17,
A transmission case 6 containing a transmission 5 including a hydraulic continuously variable transmission HST which is a main transmission and an auxiliary transmission gear 18, and a differential gear, a PTO transmission gear, etc. A traveling transmission case 21 and the like, which is connected to an axle housing 20 with an interior of an axle 19 that is transmitted from a dynamic gear to the front wheels 7, are integrally connected in this order. Reference numeral 22 is a bonnet, and 23 is a control floor, which covers the mission case 6 from above to the front, and a steering handle 24, a brake petal 25, and the like are arranged in the control seat 4 and in the front.

The drive shaft 11 and the traveling shaft 15 in the clutch housing 14 are meshed and transmitted by a gear 26.
A clutch shifter cylinder 27 for disengaging the main clutch 13 is provided on the outer periphery of the drive shaft 1.
The TO shaft 12 and the TO shaft 12 are meshed and transmitted via an intermediate gear 28. Reference numeral 29 is a clutch arm for operating the main clutch 13 for opening and closing.

The transmission case 6 is connected to the interlocking shaft housing 17 at the upper part thereof at the hydraulic continuously variable transmission HS.
Position T, connect the traveling shaft 16 to the input shaft 30, connect the front output shaft 31 to the output gear 32, and operate the control arm 33 to move from the neutral position of transmission stop to
The main transmission is configured by sequentially shifting gears to the forward high speed position and the reverse high speed position.

At the front portion of the transmission case 6, a sub-transmission shaft 34 which is interlocked with a differential gear is provided in front of the output shaft 31.
The PTO shaft 12 and the rear wheel output shaft 35 are provided along the auxiliary transmission shaft 34, and the auxiliary transmission gear 18 on the auxiliary transmission shaft 34 is provided.
And a gear shaft 36 which is rotatable around the outer circumference of the PTO shaft 12 is configured to perform an auxiliary shift. The gear shaft 36 is rotated by meshing with the output gear 32. Also, the gear shaft 36
A rotatable intermediate gear 37 is provided at a front end portion of the rear wheel output gear 38, which rotates integrally with the auxiliary transmission shaft 34, from the rear wheel output gear 38 through the intermediate gear 37.
The rear wheel 3 is transmitted from the sub-transmission shaft 34 in an interlocking manner with the gear 9. Use this clutch gear 39 as the intermediate gear 3
By removing the rear wheel 3 from the vehicle 7, a two-wheel drive mode in which the rear wheel 3 is not transmitted can be realized.

The axle housing 40 of the rear wheel 3 is supported on the lower side of the rear axle bracket 41 so as to be swingable about the center pivot 42, and is transmitted from the differential gear at the center to the left and right axles. The pair of left and right rear wheels 3 that are interlocked with the axle is interlocked by the steering handle 24 via a steering arm 43, a tie rod 44, and the like. A rear wheel drive shaft 45 on the center pivot 42 is interlocked with a front rear wheel output shaft 35 by a transmission shaft 9 via a universal joint or the like.

The brake 8 of the rear wheel 3 is a brake drum 46 that is integrally rotated with a transmission shaft 63 that is transmitted from the rear wheel output shaft 35 via a full-time four-wheel drive device 62, and a brake fixed to the transmission case 6. The brake shoe 48 in the case 47, a brake cam 49 for expanding and contracting the brake shoe 48, etc.
The brake 8 can be braked by rotating the brake pedal 9 by depressing the brake petal 25. Further, when the brake pedal 25 is depressed, the brake 51 in the axle housing 20 of the front wheel 7 can be braked via the interlocking mechanism 50.

Although the brake 8 is provided on the front side of the mission case 6, it may be provided inside the mission case 6 in the form of a multi-disc. Brake petal 2
A pair of left and right steering petals 82 and 83 are provided on the inner side of the vehicle 5, and the steering brakes 51 of the front wheels 7 on the opposite sides are braked to facilitate steering or turning. When stepping on the brake petal 25, these left and right steering petals 82, 8
Since it is similar to stepping on the pedals 3 at the same time, instead of the brake petal 25, the left and right steering petals 82 and 83 may be integrally switchable.

Reference numeral 52 is a transmission shaft cover, and 53 is an auxiliary transmission gear 1.
8 is a gear shift lever for gear shifting operation, and 54 is a radiator on the rear side of the engine E. The full-time four-wheel drive device 62
Is provided between the rear wheel output shaft 35 and the transmission shaft 63. In the illustrated example, the slipping clutch that slips when a constant rotation difference occurs between the rear wheel output shaft 35 and the transmission shaft 63. And the form. A collar 64 integrated on the rear wheel output shaft 35, a clutch disc 65, and a shifter collar 6 axially moved by the clutch shifter.
6 and the transmission shaft 63 has an integrally rotating clutch disc 67.
The axially opposed surfaces of 67 are wave-shaped clutch teeth A and B,
Torque can be transmitted by the meshing of the concavo-convex clutch teeth A and B, and slip is generated when the torque exceeds a certain level.

C and D are cams having a waveform between the back surface of the clutch disc 65 and the clutch seat 69 integral with the collar 64 in order to move the clutch disc 65 in the axial direction. When the clutch disc 65 rotates about the axis, the clutch disc 65 itself is moved in the axial direction to approach the opponent clutch disc 67 side, and the uneven clutch teeth A and B are engaged and continuously connected. To do.

A clutch case 70 for covering the clutch disks 65, 67 and the like is rotatably provided with respect to the transmission shaft 63. The clutch case 70 has a brake 71 on the outer periphery and is engaged with the transmission case 6. A brake ring 73 having a locking protrusion 72 is rotatably fitted and held, and an arm 74 projecting from the brake 71 in the axial direction is engaged with the outer peripheral portion of the clutch disc 65, whereby the brake 71 is released. By applying a braking resistance lightly to the brake ring 73, the clutch disc 65, which is braked by the engagement of the locking protrusion 72 and the arm 74, has a clutch seat of the rotating collar 64. The clutch disc 6 is pushed in the axial direction by 69.
The clutch discs 65 and 67 rotate integrally with each other by engaging with 7. 75 is a spring, and these clutch discs 65 and 6
It works in the direction to push open between 7 and.

As a result, when the rotation of the rear wheel output shaft 35 becomes larger than the rotation of the transmission shaft 63, the brake 7
The clutch disc 65 that receives the rotational resistance due to
Even if the clutch teeth A and B between the clutch disc 67 and the clutch disc 67 are disengaged by the spring 75, the cam C of the clutch seat 69 pushes the clutch disc 67 and the cam D in the axial direction against the spring 75, Clutch tooth A of clutch disc 67
Is engaged with the clutch teeth B of the clutch disc 67.
As a result, the rear wheel 3 is driven by being transmitted from the rear wheel output shaft 35 to the transmission shaft 63. In this state, the brake ring 73 does not rotate, but the brake 71 and the arm 74 are not rotated.
And the like rotate together with the clutch case 70 and generate a weak frictional resistance between the brake ring 73 and the brake 71.

On the other hand, when the transmission shaft 63 becomes larger than the rotation of the rear wheel output shaft 35, the cam A advances from the cam B in the rotational direction and separates from the cam B, so that the pressing force by the cam B disappears and the clutch disc 65 is removed. The clutch teeth A and B are disengaged by being pushed back by the spring 75, the transmission shaft 63 is not driven, and the two-wheel drive 2WD state is achieved by the front wheel 7 regardless of the rear wheel 3 that freely rotates.

The shifter collar 66 is the clutch seat 6
9 has a pin 76 held parallel to the axial direction, and the clutch disc 65 can be pushed to the 67 side via this pin 76. The shifter collar 66 causes the clutch teeth A and B of the clutch discs 65 and 67 to move to the cams C and D.
When forced to occlude regardless of the action of the
Is driven to drive the four-wheel drive 4 by the front wheels 7 and the rear wheels 3.
The WD state is set.

A case will be described in which the shifter collar 66 of the full-time four-wheel drive system 62 is operated in conjunction with the brake petal 25 for braking the brake 8. That is, one of the left and right steering petals 82, or
When the driver depresses 83, the steering brake 51 on the steering side is activated via the arm 85, the interlocking mechanism 50, the steering arm 86, etc., which can be connected to the steering petals 82, 83 on the pedaling side. The turning traveling is performed. Brake petal 25
When stepping on, the pair of left and right arms 85 on the petal shaft 87 are rotated together and the left and right steering arms 86 are rotated, so that the left and right steering brakes 51 are simultaneously braked. Further, the brake petal 25 connects the shifter arm 84 of the shifter collar 66 in an interlocking manner to configure the four-wheel drive system 2 so that the clutch teeth A and B are forcibly engaged.

Therefore, when the brake petal 25 is stepped on, the left and right steering brakes 51 are braked together, and the full-time four-wheel drive device 62 is forcedly operated to drive the four-wheel drive 4W.
The D state is set. An HST petal 77 for performing a shift operation of the hydraulic continuously variable transmission HST is provided on the control floor 23. When the HST petal 77 is stepped forward from the neutral position N to rotate, the forward speed increase is performed, and when the HST petal 77 is stepped backward and rotated, the reverse speed is increased. Reference numeral 78 is a cam that rotates integrally with the HST petal 77 about a petal shaft 79, 80 is a rod that connects the cam 78 and the control arm 33, and 81 is a positioning arm for positioning the control arm 33.

Note that such a full-time four-wheel drive device 62 may be electromagnetically switched, a mode using an operating gear, a mode utilizing the viscosity of silicon oil, or the like. Also, the front wheel output shaft 3 on the front wheel 7 side
In addition to the above, when the rotation speed of the transmission shaft 63 on the rear wheel 3 side is higher than 5, the front wheel 7 is driven to rotate when the front wheel 7 is braked, when the rear wheel 3 is steered and turned. There are times when the car slips on the ground.

A mower 55 is movably connected to the front side of the vehicle body 1 by a lift link 56, and the front end of the PTO shaft 12 is interlocked via a transmission shaft 57 and a universal joint.
A belt is transmitted from the cutting blade drive shaft on the deck to each cutting blade shaft.

[Brief description of drawings]

 The figure shows an embodiment of the invention.

FIG. 1 is a side view.

FIG. 2 is a vertical sectional view of a mission case portion.

FIG. 3 is a side sectional view of a clutch housing part.

FIG. 4 is a plan view of a rear wheel portion.

FIG. 5 is an enlarged side sectional view of a part thereof.

FIG. 6 is a side view showing a part of the operating mechanism.

FIG. 7 is a developed plan view of a clutch tooth portion of a 2WD / 4WD switching device.

FIG. 8 is a plan view of a control floor section.

[Explanation of symbols]

 2 4WD interlocking device 3 Rear wheel 7 Front wheel 25 Brake petal 62 Full-time four-wheel drive device 2WD Two-wheel drive 4WD Four-wheel drive

Claims (1)

[Claims] 1. A brake petal for braking both left and right front wheels 7 in full-time four-wheel drive in which front and rear wheels 7, 3 are automatically switched to four-wheel drive 4WD by slipping front wheels 7 by two-wheel drive 2WD. A wheel drive device for a tractor provided with a four-wheel drive interlocking device 2 for forcibly switching from two-wheel drive 2WD to four-wheel drive 4WD by stepping on 25.