JPH0243664B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a front wheel brake device for a four-wheel drive tractor.

[Prior art and problems to be solved by the invention] Four-wheel drive tractors are widely used in order to utilize the wheel drop of the front wheels of the tractor as traction friction force, but the front wheels are not equipped with a brake device. Therefore, when sudden braking is required, the braking force is insufficient and the sudden stop is insufficient.Furthermore, since the front wheels cannot be braked, the turning radius becomes large. Therefore, we solved the lack of braking force during sudden braking, and without impairing the turning performance when turning the steering wheel.
A technical problem arises that must be solved in order to reduce the turning radius of the front wheels so that the vehicle can turn around quickly, and the present invention aims to solve this problem.

This invention was proposed to achieve the above object, and a stationary side gear case is attached to the outer end of the front axle housing which pivotally supports the front wheel drive shaft. In a four-wheel drive tractor in which a side gear case is fitted to a fixed side gear case so as to be able to steer and turn, and a turning center axis provided at the turning center, a front wheel drive shaft, and a front wheel axle are interlocked by a gear mechanism. , open the upper end of the stationary side case that houses the rotation center axis, attach an upper cover to the upper end of the stationary side case so as to close the opening, and further rotate the rotation center axis on the upper side of the upper cover. A journal boss is provided that fits into the journal hole of the knuckle arm fixed to the side gear case, and a cylindrical brake chamber is fitted inside near the opening on the inside of the upper end of the stationary side gear case, and a cylindrical brake chamber is fitted inside the upper end of the fixed side gear case. Friction plates and pressure plates are interposed alternately, and the friction plate engages with the rotation center shaft, and the pressure plate engages with an engagement groove provided on the side surface of the brake chamber to generate hydraulic pressure. It is an object of the present invention to provide a front wheel brake device for a four-wheel drive tractor characterized by comprising a brake section.

[Function] By applying the brakes to the front wheels, the braking force is greater than conventional braking of only the rear wheels, making it possible to stop suddenly. Also, by applying the brakes to the front wheels on the inside of the turning wheel, It has also become possible to reduce the turning radius. In addition, a hydraulic brake section 28 is installed in the upper part of the fixed side gear case 3 in order to apply a brake to the turning center axis 12 provided in the fixed side gear case 3 fixed to the front axle housing 2. Gear case 3 is
It has almost the same shape as a normal stationary side gear case that does not have a brake device, and avoids complicating the shape such as a brake member protruding from the outside. This made it possible to avoid problems and high costs.

[Embodiment] An embodiment of the present invention will be described below. The front wheel drive device illustrated in FIG. Attach the knuckle arm 6 to the upper part of the turning side gear case 5 that pivotally supports the front wheel shaft 4, and connect the journal hole 7 formed in the knuckle arm 6 and the lower journal hole 8 of the turning side gear case 5 to the fixed side. Journal boss 1 of upper cover 9 attached to upper end opening A of gear case 3
0 and the lower cylindrical journal boss 11 of the stationary side gear case 3, and when the knuckle arm 6 is rotated by a steering mechanism (not shown), the rotation side gear case 5 rotates the above-mentioned fitting part. The steering will be turned around the center, and the fixed side gear case 3
The bevel gear 14 is pivotally supported by a bearing 13 near the upper end opening A of the fixed side gear case 3 and the rotating side gear case 5 via a bearing 15. The bevel gear 14 is fitted onto the front wheel drive shaft 1.
The bevel gear 17 of the rotation center shaft 12 and the bevel gear 18 loosely fitted to the front wheel shaft 4 are meshed with each other, and the sun gear 19 and the outer cover 20 are integrated with the bevel gear 18.
A plurality of planetary gears 22 meshing with both internal gears 21 attached to the rotation side gear case 5 (which covers the outer end opening of the rotation side gear case 5) are supported by a carrier 23 fitted on the front wheel shaft 4. Bevel gear mechanism 24 consisting of bevel gears 16, 14 and bevel gears 17, 18
a bevel gear mechanism 25 and a sun gear 19,
The front wheel drive shaft 1 is assembled with a planetary gear mechanism 26 consisting of a planetary gear 22, a carrier 23, and an internal gear 21.
A gear mechanism 27 that decelerates the rotation of and transmits it to the front wheel shaft 4
It is composed of A brake chamber B is formed above the bevel gear 14 near the upper end opening A of the stationary gear case 3, and a hydraulic brake section 28 for braking the turning center shaft 12 is installed inside the brake chamber B, and the brake pedal The pressure oil generated by the master cylinder 30 in response to the depressing operation of the brake pedal 29 is supplied to the hydraulic brake section 28, thereby causing the hydraulic brake section 28 to perform a braking operation.

That is, in the illustrated example, the cylinder 31 is inserted into the brake chamber B from the upper end opening A, the lower end of the outer circumference of the cylinder 31 is brought into contact with the outer ring of the bearing 13, and the piston 32 is fitted into the cylinder 31 and rotated. Fits loosely into the center shaft 12. On the other hand, in order to provide tooth-shaped engagement grooves 33, 33, . …of,
Further, a spline boss 34 is provided on each of the rotation center shafts 12 in the upper part of the piston 32.
Between the stopper plate 36 and the piston 32, which are fixed to the upper end with bolts 35, friction plates 37, 37... and pressure plate 3 are installed.
8, 38... are interposed alternately, the friction plate 37 engages the tooth-shaped engagement groove provided in its inner hole with the spline boss 34, and the pressure plate 38 is provided on its outer periphery. The tooth-shaped engagement groove is engaged with the engagement groove 33 of the upper cover 9, a return spring 39 is interposed between the piston 32 and the pressure plate 38, and the pressure oil of the master cylinder 30 is released from the oil passage 40. It is supplied to the lower surface of the piston 32.

The front axle housing 2 is the second
As shown in the figure, the front and rear center pivot parts 41 and 42 provided at the left and right center portions are fitted into the pivot holes 44 and 45 of the front frame 43 of the tractor, so that the left and right parts are centered around the center pivot parts 41 and 42. An input shaft 46 that can swing vertically and is driven by the transmission mechanism of the tractor via a transmission shaft.
A drive pinion shaft 48 is driven by a spur gear mechanism 47, and this drive pinion shaft 48 drives the left and right front wheel drive shafts 1 through a front wheel differential mechanism 49, respectively.

Therefore, when the brake pedal 29 is not depressed, pressure oil is not supplied to the lower surface of the piston 32, so the pressure plate 38 and the friction plate 37 are separated from each other, and the rotation center shaft 12 is moved by the bevel gear mechanism 24. When the brake pedal 29 is depressed, pressure oil is released into the piston 32.
is pushed upward against the return spring 39, so the piston 32, pressure plate 38, friction plate 37, and stopper plate 36 are integrally connected, and the plate engaged with the upper cover 9 Since the shear plate 38 and the friction plate 37 engaged with the rotation center shaft 12 are integrated, a brake is applied to the rotation center shaft 12.

In addition, each member of the bevel gear 14 and the hydraulic brake part 28 is connected to the fixed side gear case 3 from the upper end opening A.
Also, bevel gears 17 and 18
The planetary gear mechanism 26 and the like are connected to the rotation side gear case 5.
It will be assembled into the rotation side gear case 5 from the outer opening of.

Therefore, if the upper cover 9 is removed, the upper end opening A
You can easily inspect the hydraulic brake part 28 and replace each member from the stationary side gear case 3 and rotating side gear case 5.
This has the advantage that it can be done without having to drain the lubricating oil inside.

Note that the illustrated gear mechanism 27 is the bevel gear mechanism 2.
5 and a planetary gear mechanism 26 with a large reduction ratio, the braking force of the hydraulic brake section 28 necessary for braking the turning center shaft 12 is equal to the braking force of the front wheel shaft 4.
It also has the advantage of requiring less force than braking directly. However, the gear mechanism 27 is not limited to the illustrated example, and may be one without a planetary gear mechanism.

[Effects of the Invention] As described in detail in the above embodiment, the present invention forms an upper end opening A centered on the rotation center shaft 12 in the stationary side gear case 3 near the upper part of the rotation center shaft 12. A journal boss 10 that fits inside the journal 7 of the knuckle arm 6 fixed to the rotation side gear case 5 is provided on the upper side of the upper cover 9 that closes the upper end opening A, and an upper end opening is provided on the lower side of the upper cover 9. A cylindrical brake chamber B that is almost entirely fitted inside part A is integrally provided, and a plurality of engagement grooves 33 are formed along the axial direction from the end of this brake chamber B, and a rotation center A spline boss 34 is formed at the upper end of the shaft 12, and a spline boss 34 is formed at the upper end of the shaft 12 to connect the brake chamber B and the rotation center shaft 1.
Since the hydraulic brake part 28 is provided between the upper part of the brake chamber B, the plurality of engagement grooves 3 formed in the brake chamber B
3 can be easily processed, and the brake chamber B can be provided without particularly protruding above the turning side gear case 5. Therefore, the turning performance during steering turning is not impaired, and the brake chamber B can be provided easily. This makes it possible to operate the vehicle, and since it compensates for the lack of braking power provided by the conventional rear wheels, it is possible to stop suddenly.Furthermore, since the brake is applied to the front wheel on the turning side, it is also possible to reduce the turning radius and make small turns. Furthermore, since the piping for supplying and discharging the hydraulic pressure of the hydraulic brake section 28 is connected to the stationary side gear case 3, this piping is not moved in conjunction with the turning movement of the steering wheel. can be fixed to the front axle housing in an attractive manner.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, in which FIG. 1 is a longitudinal sectional front view of a main part of a front wheel drive device, and FIG. 2 is a longitudinal sectional side view of a main part of a front wheel differential mechanism. DESCRIPTION OF SYMBOLS 1... Front wheel drive shaft, 2... Front axle housing, 3... Fixed side gear case, 4... Front wheel axle, 5... Turning side gear case, 12... Turning center axis, 27... Gear mechanism, 28 ...Hydraulic brake section, B...Brake chamber.

Claims (1)

[Claims] 1. Attach the stationary side gear case to the outer end of the front axle housing that pivotally supports the front wheel drive shaft, and fit the turning side gear case that pivotally supports the front wheel shaft to the stationary side gear case so that steering and turning is possible. In a four-wheel drive tractor in which the turning center shaft provided at the turning center and the front wheel drive shaft and the front wheel axle are linked by a gear mechanism, the upper end of the fixed side case housing the turning center shaft is opened. Then, an upper cover is attached to the upper end of the stationary side case so as to close the opening, and a journal boss is fitted on the upper side of the upper cover to fit into the journal hole of the knuckle arm fixed to the rotation side gear case. At the same time, a cylindrical brake chamber is fitted in the vicinity of the opening inside the upper end of the stationary side gear case, and friction plates and pressure plates are alternately interposed above the rotation center shaft. A front wheel of a four-wheel drive tractor, characterized in that the compression plate engages with the rotation center axis, and the pressure plate engages with an engagement groove provided on a side surface of the brake chamber to constitute a hydraulic brake section. Brake device.