JPH0858408A - Steering wheel driving device in working vehicle - Google Patents

Abstract

PURPOSE: To surely operate a steering wheel driving device, to dispense with an exclusive case, and to easily attach or detach a torque limiter by providing the torque limiter in the midst of a power transmitting system extending from an input shaft, which is accommodated in an axle housing, to an input gear of a differential device. CONSTITUTION: A differential device (D) is accommodated in the lower part of an axle housing (H), while a ring gear 5 of the differential device (D) is engaged with an input gear 6 of the device (D). Both a diff. input shaft 6a and an input shaft 10 are supported between a housing main body 1 and a cover 9, while a gear 7 is engaged with a gear 11, which is loosely fitted on the input shaft 10. A torque limiter (T) is interposed between the gear 11 and the input shaft 10 in order to transmit the power from the input shaft 10 to the differential device (D). When an excessive load is imposed in driving a front wheel, a slip is caused on the part of friction plates 13, 13..., thereby cancelling excessive force. Thus, since the torque limiter is installed in the place where the torque is constant, the steering action is stabilized.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a four-wheel drive vehicle,
The present invention relates to a configuration for preventing damage to a drive system of a steering wheel when an excessive load is temporarily applied to the steering wheel.

[0002]

2. Description of the Related Art Conventionally, in order to drive the front wheels of a four-wheel drive vehicle such as an agricultural tractor, a drive shaft protruding from a transmission case and an input shaft of an axle housing are connected by a drive shaft having a universal joint. It was And
When a work machine such as a front loader is attached to the front of the machine to perform work, the resistance of the steering wheel increases and the drive system of the steering wheel such as the differential gear installed in the axle housing is damaged. In some cases, the vehicle may become unable to run, and therefore, for example, Japanese Utility Model Laid-Open No. 54-37639 and US Pat.
As in the technique of No. 9, it has been proposed to provide a friction multiple plate type torque limiter on one side of the drive shaft.

[0003]

However, in any of the conventional techniques, since the torque limiter is arranged at the place where the torque fluctuation is large, the operation is unstable, the size is large, and the cost is high. In addition, the actual Kaisho 54-
Since the technology of No. 37639 is composed of a dry clutch, it is not suitable for long-term use. US Patent No. 2
The technology of 977779 is a wet clutch, but it requires a special case for it, so it becomes larger than the dry type.

[0004]

The present invention uses the following means in order to solve the above problems. That is, a diff device is installed inside an axle housing suspended on the vehicle body, and a pair of left and right output shafts of the diff device are used to
In a device for driving a pair of left and right steering wheels, a torque limiter is provided in the middle of a power transmission system from an input shaft housed in the axle housing to an input gear of a differential device.

Further, in a device in which a diff device is installed in an axle housing suspended on a vehicle body, and a pair of left and right steering wheels are driven through a pair of left and right output shafts of the diff device, the diff device is moved from an input shaft. A multi-plate friction type torque limiter was provided in the middle of the power transmission system leading to the input gear, and the torque limiter was immersed in the lubricating oil in the axle housing.

Further, in a device in which a diff device is housed in an axle housing suspended on a vehicle body, and a pair of left and right steering wheels are driven via a pair of left and right output shafts of the diff device, the diff device is moved from an input shaft. A multi-plate friction type torque limiter was installed in the middle of the power transmission system leading to the input gear of (1), and was housed in one chamber defined in the axle housing, and a viscous fluid was sealed in the chamber.

Further, the torque limiter is of a variable torque set value type, and is linked to a steering operation system of the steered wheels so as to weaken the torque set value as the steering angle of the steered wheels increases. did.

[0008]

Next, the operation will be described. Power is transmitted from the front-wheel drive take-out shaft of the transmission case of this machine to the input shaft to the axle housing via the joint and drive shaft, and the power is transmitted from the input shaft to the differential device from the differential input shaft via the torque limiter. Then, the steering wheel is driven. At this time,
Since the torque limiter is immersed in the lubricating oil in the differential device, no wear occurs. When the steering wheel is overloaded, slippage occurs at the friction plate portion of the torque limiter, and excessive torque is not applied to the differential device side, which prevents damage to the drive system of the steering wheel. In addition, the torque limiter is a variable torque setting value, and the steering is linked to the torque limiter, and as the turning angle of the steering increases,
If the torque of the torque limiter is weakened, slippage will increase and two-wheel drive will automatically be performed.

[0009]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a side view of a tractor equipped with a front loader, FIG. 2 is a side sectional view of a first embodiment in which a torque limiter is arranged in an axle housing, and FIG. 3 is a side sectional view of a second embodiment of the torque limiter. 4 is a side sectional view showing the third embodiment, FIG. 5 is a side sectional view showing the fourth embodiment, FIG. 6 is a bottom sectional view of an embodiment in which a torque limiter is linked to a steering operation system, and FIG. AA in FIG.
FIG. 8 is a sectional view taken along the arrow, and FIG. 8 is a side sectional view of an embodiment in which the input shaft and the differential input shaft are arranged on the same axis.

A case where the four-wheel drive vehicle is, for example, a tractor will be described. In FIG. 1, front wheels 21 serving as steering wheels are suspended on both sides of an axle 20 protruding from both sides of a front axle housing H, and a rear axle housing 2 is provided.
A rear wheel 24 is suspended on an axle 23 that projects from both sides. Further, the power from the engine in the hood 25 is transmitted to the transmission case 26 to change the speed, the rear wheels 24 are driven via the rear differential device, and the front wheel drive shaft projecting forward from the transmission case 26 causes a universal joint. Is transmitted to the input shaft 10 described later via the drive shaft 27 and the front wheels 21 are driven.

A front loader F is mounted as a front working machine, and a column 29 standing upright on the rear portion of the front frame 30 is reinforced by frames 31 and 32 extending to the front portion of the front frame 30. The base of the lift arm 33 is pivotally supported on the lift arm 33.
A bucket 34 is attached to the tip of the lift cylinder 3
5 and the bucket cylinder 36 are expanded and contracted so that scooping work can be performed.

The axle housing H is a housing body 1
And the cover 9 are connected in front and back. As shown in FIG.
The upper part of the housing body 1 is provided with a pivot hole 1a extending in the front-rear direction, the center pin 2 is inserted into the pivot hole 1a, and both front and rear sides of the center pin 2 are fixed by the support plates 3 and 3. The plates 3 and 3 are attached to the front frame 30.
It is fixed to and supports the axle housing H so as to be swingable from side to side. A diff device D is housed in the lower portion of the axle housing H, and a pair of left and right output shafts 4 that are differentially connected by the diff device D are supported by the housing body 1, and a reduction transmission mechanism from the outer end of the housing ( The front wheels 21 can be driven via an axle 20 (not shown).

A differential input gear 6 is meshed with the ring gear 5 of the differential device D, and the differential input gear 6 is formed at one end of the differential input shaft 6a, and the gear 7 is provided on the differential input shaft 6a. Is fixed. A differential input shaft 6a and an input shaft 10 are rotatably supported in parallel between the housing body 1 and the cover 9, and the gear 7 meshes with a gear 11 loosely fitted on the input shaft 10. Then, a torque limiter T is provided between the gear 11 and the input shaft 10, and the input shaft 10
From the differential device D to the power transmission.

The torque limiter T is a friction multi-plate type,
One end of a cylindrical limiter case 12 is attached to the gear 11, and friction plates 13.1 are respectively provided between the groove of the limiter case 12 and the spline groove 10a formed on the input shaft 10.
3 ... are alternately arranged, and the friction plates 13
..Double coil springs 14 so as to press-contact
A plurality of sets 15 are arranged around the input shaft 10 between the side surface of the friction plate 13 and the limiter case 12. In this embodiment, the double coil springs 14 and 15 are used, but if the specified torque setting value can be obtained, various spring urging means such as a single coil spring and a disc spring can be used. You can And axle housing H
Lubricating oil is filled therein to lubricate the differential device D, and the torque limiter T is arranged so as to be immersed in the lubricating oil.

With this structure, power is transmitted from the input shaft 10 to the axle 20 via the gear 11, the gear 7, the differential input shaft 6a, and the differential device D via the torque limiter T to drive the front wheel 21. Then, the vehicle travels with the driving of the rear wheels 24. However, when the bucket 34 of the front loader F scoops in the earth during work, or when the vehicle suddenly starts with the earth and sand loaded, an excessive load is applied to the driving of the front wheels 21. It often happens that the friction plate 13 of the torque limiter T
The slippage occurs at the portion 13 ... so that excessive force is not applied to prevent damage to the drive system of the front wheels 21.

As another embodiment of the torque limiter T, as shown in FIG. 3, the gear 11 and the limiter case 11a.
It is also possible to integrally configure. As another embodiment, as shown in FIG. 4, the bearing 16 provided in the housing body 1 for supporting the differential input shaft 6a is a seal type, and the chamber B for housing the differential device D and the torque limiter T are provided. Torque limiter T divided into compartment C
A viscous fluid (such as syrincon oil) is enclosed in a chamber C that stores the.

As another embodiment of the torque limiter T, as shown in FIG. 5, a friction cone type can be used instead of the friction multiple plate type, and the drive side cone 17 is provided on the input shaft 10. Splined so that it can slide axially,
On the other hand, the driven-side cone 18 is loosely fitted to the input shaft 10 so that the gear 1
1 and the driving side cone 17 is driven side cone 18
Energize with springs 14 and 15 so as to press against
When no load is applied, the driving side cone 17 and the driven side cone 18 are pressed against each other and rotate at the same time due to friction, and when an overload is applied to the front wheel side, slippage occurs and the driving force to the front wheel side is reduced. .

Further, the torque limiter T is constructed so that its set torque value can be changed. That is, as shown in FIG. 6 and FIG. 7, the pressing plate 40 that is not rotatable relative to the limiter case 12 and is axially slidable between the friction plate 13 and the springs 14 and 15 is provided.
The ring-shaped disc 41 on the pressure plate 40.
Of the disk 41, the arm 42 is brought into contact with the surface of the disk 41 opposite to the springs 14 and 15, and the arm 42 is fixed to the shaft 43 supported by the cover 9, A rotation arm 44 is fixedly provided at one end of the shaft 43 outside the shaft 9.

The torque limiter configured as described above is
When the steering handle 37 is turned to the left or right, the turning arm 44 is turned in proportion to the turning amount,
The arm 42 pushes the disc 41 and the plate 40 in the anti-spring biasing direction to reduce the frictional force between the friction plates 13 ...
It is linked to a steering operation link system of the steering handle 37 via a link mechanism or the like. That is, as the turning angle increases, the transmission torque decreases, the driving force of the front wheels 21 decreases, the driving load decreases, and the road surface is not roughened.

Further, the torque limiter T may be arranged in the power transmission path from the input shaft 10 to the differential input shaft 6a, and its arrangement position is not limited, and the torque limiter T is another embodiment. As shown in FIG. 8, a limiter case 6b is integrally or separately provided at the rear end of the differential input shaft 6a, and the friction plates 13, 13 ,.
.. and the tip of input shaft 10 and coil spring 14.1
Alternatively, the torque limiter T may be accommodated to accommodate 5 and the differential input shaft 6a and the input shaft 10 may be arranged on the same axis. With this configuration, a compact configuration can be achieved.

[0021]

Since the present invention is constructed as described above, it has the following effects. That is, according to the first aspect of the invention, the torque limiter is provided at a position where the torque is constant, so that the operation is stable and operates reliably. Further, since it is itself surrounded by the axle housing, a special case is not necessary. Further, by disassembling the axle housing, the torque limiter can be removed and the torque set value can be adjusted relatively easily.

According to the second aspect of the present invention, since the shock is small at the time of engagement and disengagement and the friction is a multi-plate type, the lubrication is surely performed and the function of the torque limiter can be exerted for a long time. The cost can be reduced by using the lubricating oil for the differential device in the axle housing.

According to the third aspect of the present invention, the friction is ensured and the function of the torque limiter can be exerted for a long period of time in spite of the fact that there is little shock at the time of engagement and disengagement and the friction is a multi-plate type. By using a viscous fluid different from that for the differential device in the axle housing, the lubricating oil can increase the friction coefficient of the torque limiter, reduce the size of the friction plate, and reduce the friction plate. The torque limiter can be made compact by reducing the number of sheets.

Since the driving torque is weakened in proportion to the turning angle and the driving force is transmitted to the steered wheels when the vehicle is straight ahead, stable driving is possible, and the two-wheel drive is provided when the vehicle makes a sharp turn. As a result, the diff device on the steering wheel side is not overloaded, damage is prevented, and the ground is not roughened by the grip force of the steering wheel.

[Brief description of drawings]

FIG. 1 is a side view in which a front loader is attached to a tractor.

FIG. 2 is a side sectional view of a first embodiment in which a torque limiter is arranged inside an axle housing.

FIG. 3 is a side sectional view showing a second embodiment of the torque limiter.

FIG. 4 is a side sectional view showing a third embodiment of the same.

FIG. 5 is a side sectional view showing a fourth embodiment of the same.

FIG. 6 is a bottom cross-sectional view of an embodiment in which a torque limiter is linked to a steering operation system.

FIG. 7 is a sectional view taken along the line AA in FIG.

FIG. 8 is a side sectional view of an embodiment in which the input shaft and the differential input shaft are arranged on the same axis.

[Explanation of symbols]

 D differential device T torque limiter H axle housing 4 output shaft 6a differential input shaft 10 input shaft 13 friction plate 21 front wheel 37 steering wheel

Claims (4)

[Claims] 1. A device for mounting a diff device in an axle housing suspended from a vehicle body and driving a pair of left and right steering wheels through a pair of left and right output shafts of the diff device. A steering wheel drive device for a work vehicle, wherein a torque limiter is provided in the middle of a power transmission system from the input shaft housed in the input device to the input gear of the differential device. 2. A device for mounting a diff device in an axle housing suspended on a vehicle body, and driving a pair of left and right steering wheels via a pair of left and right output shafts of the diff device. A friction wheel multi-plate torque limiter is provided in the middle of a power transmission system up to the input gear, and the torque limiter is immersed in the lubricating oil in the axle housing. 3. A diff device in which a diff device is housed in an axle housing suspended from a vehicle body, and a pair of left and right steering wheels are driven through a pair of left and right output shafts of the diff device. Characterized in that a friction multi-plate torque limiter is interposed in the middle of the power transmission system leading to the input gear of (1), and is housed in a chamber defined in the axle housing, and a viscous fluid is enclosed in the chamber. Steering wheel drive for work vehicles. 4. The torque limiter according to claim 1, 2 or 3, wherein the torque limiter is of a variable torque set value type, and the torque set value is weakened as the steering angle of the steered wheels increases. A steering wheel drive system for a working vehicle, wherein the steering wheel drive system is linked to the steering operation system of the steering wheel.