JPH0635751Y2 - Front wheel speed increasing device for agricultural tractor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to a front wheel speed increasing device for an agricultural tractor having a differential device for front wheel speed increasing.

(B) Prior art Conventionally, a four-wheel drive state in which a diff device is used as a front wheel speed-increasing device, and a dock clutch having a rear diff shaft spline-fitted thereto meshes with the diff case to rotate integrally with the diff case, Two driving state with the clutch disengaged,
The agricultural tractor in which the above clutch is docked in a fixed case and is switched to the front wheel double speed state is an actual open sho 59-6662.
It is already known from the publication No. 7, etc.

(C) Problems to be solved by the invention The known agricultural tractor is extremely dangerous because the speed increases all at once when the dock clutch engages with the fixed case when the machine is traveling.

When a brake was attached to the diff shaft (the rear one in the above-mentioned known device) that was locked to solve such a problem to prevent the speed from being doubled at once, a dock clutch was attached to this diff shaft. The brake was not able to be interposed because it was arranged to keep the 4WD state normally by compressing it forward in the rear part.

(D) Means for Solving the Problems The present invention relates to a four-wheel drive agricultural tractor in which a front wheel drive system is provided with a speed increasing differential device to increase the speed of the front wheels. At one end of the diff case of the device, a cylinder part in which an input diff shaft is installed is continuously provided, an input gear is attached to the cylinder part, and a diff lock mechanism for connecting and disconnecting the cylinder part and the input diff shaft is provided. The above problem was solved by mounting a brake on the differential shaft.

(E) Action The engine power is distributed to the front and rear wheels, and the cylinder part that is integral with the differential case of the speed increasing diff device interposed in the front wheel transmission system is
When rotating through the input gear and releasing the diff lock mechanism, the connection between the tubular portion and the input diff shaft is cut off, the power is not transmitted to the input diff shaft, and the front wheels are not driven into the two-wheel drive state, When the lock mechanism is locked, the input diff shaft and the cylindrical part of the diff case are linked to rotate integrally and become the 4WD state.When the brake is operated in the diff lock released state, the input diff shaft increases as the braking force increases. Gradually decreases its rotation and stops, and accordingly, the front wheels are sequentially accelerated and then driven at double speed.

(F) Embodiment An embodiment of the present invention will be described with reference to the drawings. The power of the engine 1 is the flywheel 1a in the clutch housing A,
It is transmitted to the lower side via the main clutch 2 and the gears 3 and 4 at the rear part thereof, and the gear 4 at the lower side is spline-fitted to the front end of the cylinder shaft 6 installed in the intermediate case 5. The power is distributed to the traveling main transmission unit 9 and the PTO transmission unit 8 of the rear mission 7, and the rear axle 13 includes the traveling main transmission unit 9 to the auxiliary transmission unit 10, the pinion shaft 11, the rear wheel differential device 12, and the rear wheel differential device 12. It is transmitted via the final speed reducer 14.

Further, the rear end of the front wheel drive shaft 16 installed in the cylindrical shaft 6 is connected to the pinion shaft 11 by a spline joint 15, and the gear 18 attached to the front end thereof is a two-stage gear which is rotatably supported at the lower portion thereof.
The input gear 20, which meshes with one gear of 19 and meshes with the lower part of the other gear, drives the front axle 22 via the speed increasing differential device 21 of the front wheel speed increasing device.

The structure of the speed increasing diff device 21 itself is the same as that of a normal one, and a bulging portion A1 is provided at the rear portion of the clutch housing A, the lower surface of which is at substantially the same height as the lower surface of the intermediate case 5. At the same time, a partition wall A2, which is slightly higher than the lower surface of the clutch housing A, is provided following the step portion a directed obliquely upward, and the front wheel speed increasing device is housed in a case surrounded by the partition wall A2 and the bulging portion A1. 23 rear (input side)
At the rear end, a cylindrical portion 25, in which the input gear 20 is spline-fitted, is projectingly provided, and the cylindrical portion 25 and the input differential shaft inserted through the cylindrical portion 25.
The diff lock mechanism for interlocking with and releasing 26 is a conical hole 27 formed on the outer periphery of the input diff shaft 26 and a cylindrical portion.
It consists of a ball 30 that fits into the hole of 25 and is pushed into or out of the conical hole 27 by sliding of the hub 28.It fits on the outer periphery of the hub 28 and the shifter 31 is placed on the side of the driver's seat. The state shown in FIG. 1 is a two-wheel drive state in which the connection is released by the operation lever provided, and the state shown in FIG. 1 is moved by the operation lever via the shifter 31 to the middle portion of the tubular portion 25. Hub 28 enters ball 30 conical hole in differential shaft 26
Since it is pushed into the 27, the cylinder part 25 of the differential case 23 and the input differential shaft
26 and 4 rotate together and become 4WD.

Further, the rear portion of the input differential shaft 26 is located below the gears 3 and 4 and the gears 19 and 20 of the front wheel drive system, which are transmitted to the rear mission 7, and a disc brake 32 is mounted. The brake plates 33 ... Are engaged with bosses that are spline-fitted to the input differential shaft 26, and the brake pieces 34 are attached to the case partition wall 35 with bolts 36. Supporting holder 37
The hydraulic cylinder which is engaged with the disk brake 32 and which operates the disc brake 32 is composed of a piston 38 and a cylinder 39, and the cylinder 39 is fitted in the hole of the case partition wall 35 through an O-ring. Since the head portion of the head portion is intruded into the intermediate case 5 whose upper surface is in the operation step, the intermediate case 5 can be used as a storage space for the speed increasing diff device 21, and the speed increasing diff device is externally provided. It is possible to prevent a large protrusion. 40 is the O that is inserted in the piston 38
It's a ring.

The return device of the piston 38 is received by a pipe 41 slidably fitted into a cylinder 39 through an O-link and the tip of which is screwed into the piston 38, and a washer 42 fixed to the outer periphery of the rear end by a C pin. And a compression spring 43 that is pushed forward by a compression spring 47 received by a C pin in the pipe 41, and a hole 48 is formed on the inner end side of the pipe 41. Drill and cylinder
A joint 50 that is communicated with the inside of the cylinder 39 to form a surplus oil chamber and screwed into the intermediate case 5 is inserted into the cylinder 39 through an oil hole 51 and is screwed to the outer end of the joint 50.
Is connected to one end of an oil guide pipe 53, and the other end of the oil guide pipe 53 is connected to the cutting angle detecting device shown in FIG.
This turning angle detection device is mounted on a front axle case 55 via brackets 56, 56, and both ends are connected to front wheel drive cases 57, 57.
Also serves as a tie rod, and detection cylinders 60, 60 having pistons 59 are attached to both ends of the steering hydraulic cylinder 58, and a receiving plate is provided on the piston rod of the steering hydraulic cylinder 58.
61, 61 are screwed together, the left and right detection cylinders 60, 60 are connected by a pipe 62, and one detection cylinder 60 is connected to the other end of the oil guide pipe 53. After moving the hub 28 to the two-wheel drive position or forward of the balls 30, the handle is rotated to open the control valve and operate the steering hydraulic cylinder 58 to move the front wheel drive cases 57 and 57 around the kingpin. Turn as.

At this time, when the cutting angle becomes large to some extent, one of the receiving plates 61 pushes the corresponding piston 59 of the detection cylinder 60, and the hydraulic oil contained in the detection cylinder 60 causes the oil guide pipe 53 and the joint 50, etc. Since the piston 38 is pushed out, the disc brake operates and the input differential shaft 26 stops, and the differential case 23 rotates in this state, the output differential shaft 63 doubles. The front axle 65 is accelerated and the front differential mechanism 66 and the front wheel drive mechanism
Driven by the output differential shaft 63 via 67.

The hydraulic oil from the detection cylinder 60 pushes the disc brake forward forward a bit to stop the tubular portion 25, and the hydraulic oil press-fitted into the cylinder 39 flows into the pipe 41 through the hole 48 and weakens the piston 46. Since it is pushed out against the compression spring 47, it is housed in the surplus oil chamber.

Further, when the steering hydraulic cylinder 58 is returned to operate and the receiving plate 61 separates from the piston 59 of the detection cylinder 60 after the end of the airframe traveling, the compression spring 43 pulls the piston 38 back through the pipe 41, and thereby the cylinder 39 is released. The hydraulic oil inside is an oil pipe
It returns to the detection cylinder 60 via 53, and finally the working oil in the surplus oil chamber is pushed out and returns.

Further, since the input gear of the speed increasing diff device 21 is mounted on the tubular portion 25, the diameter of the front wheel speed increasing device can be made smaller than that of the conventional method in which the input gear is projected from the outer periphery of the differential case, and the clutch housing A It can be mounted in a lower space or in a narrow space such as in a rear mission.

The main clutch 2 has a shaft 68, a bush 69 and a bearing 70.
The power is cut off by pushing the release boss mounted via the fork 71.

In the above-described embodiment, the bulging portion A1 and the partition wall A2 are formed integrally with the clutch housing A. However, the partition wall A2 is formed integrally with the clutch housing A, and the bulging portion A1 is formed separately and mounted by bolts. You may make it disassembleable.

(G) Effect of the Invention As described above, the present invention relates to a four-wheel drive type agricultural tractor in which the front wheel drive system is provided with the speed increasing differential device 21 to increase the speed of the front wheels. Device 21 diff case 23
A cylindrical portion 25 in which a differential shaft is installed is continuously provided at one end of the cylindrical portion.
Since the input gear 20 is attached to 25, a differential lock mechanism for connecting and disconnecting the tubular portion 25 and the input differential shaft 26 is provided, and a brake is attached to the input differential shaft 26, the tubular portion 25 of the differential case 23 is provided.
And the input diff shaft 26 installed therein can be switched between 2WD and 4WD by the intermittent operation of the diff lock mechanism at the intermediate portion of the tubular portion 25, and the brake attached to the input diff shaft 26 can be used. By operating the airframe, it is possible to perform safe airframe traveling without being accelerated at once when turning the airframe unlike the conventional one.

Further, since the input gear 20 of the front wheel speed increasing diff device 21 is attached to the tubular portion 25 extending from the diff case 23, the diameter of the input gear 20 is set to be equal to or smaller than the diff case and the speed increasing diff device 21 is miniaturized. Therefore, the speed increasing differential device 21 can be easily installed in a narrow space.

[Brief description of drawings]

The drawings show one embodiment of the present invention. FIG. 1 is a longitudinal sectional view of a main part, FIG. 2 is a transmission system diagram, FIG. 3 is a side view of a tractor showing the main part, and FIG. FIG. 4 is a plan view of a steering detection unit. 5 ... Intermediate case, 6 ... Cylindrical shaft, 7 ... Rear transmission, 16 ... Front wheel drive shaft, 20 ... Input gear, 21 ... Accelerating differential device, 23 ... Differential case, 25 ... Cylindrical part , 26 …… input differential shaft, 28 …… hub, 30 …… ball, A …… clutch housing

Claims (1)

[Scope of utility model registration request] 1. A four-wheel drive type agricultural tractor in which a front wheel drive system is provided with a speed increasing diff device 21 to increase the speed of the front wheels, and at one end of a differential case 23 of the speed increasing diff device 21. , The input differential shaft 26 is internally provided with a tubular portion 25,
A front wheel speed increasing device for an agricultural tractor, characterized in that an input gear 20 is attached to 25, a differential lock mechanism for connecting and disconnecting the tubular portion 25 and the input differential shaft 26 is provided, and a brake is attached to the input differential shaft 26. .