JP2645830B2 - Swivel device for agricultural tractor - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a turning device for an agricultural tractor that turns a body rapidly with a small radius.

[Prior Art and Problems to be Solved by the Invention] Conventionally, a differential device is attached to a front wheel drive unit and a rear wheel drive unit, and a speed increasing differential device is interposed in a front wheel drive system, and an error drive device is provided. A turning device for an agricultural tractor provided with a pawl clutch urged by a spring to defrost or lock a differential shaft is already known from Japanese Utility Model Laid-Open No. 59-66627.

The turning device in the known agricultural tractor can only intermittently connect the clutch, and if the teeth of the claw clutch are missing, transmission to the front wheel becomes impossible.

Means for Solving the Problems The present invention has been made for the purpose of solving the problems as described above, and comprises a front wheel drive unit and a rear wheel drive unit which are housed in a mission case. In the agricultural tractor in which a differential mechanism is attached to each and the transmission system to the front wheel side differential mechanism is further interposed with a speed increasing differential mechanism, a braking side of a differential case constituting the speed increasing differential mechanism is provided. The boss is formed to be long with a cylindrical shaft shape, a hub is fitted around the outer periphery of the braking side boss so as to be movable in the axial direction, and a braking shaft composed of a differential shaft is freely fitted and inserted into the inner periphery. On the other hand, a braking mechanism is provided between the braking shaft and the mission case for braking the braking shaft to bring the front wheel into a double-speed drive state, and between the braking boss and the braking shaft, Front wheel non-drive state, front wheel drive based on the movement of the hub in the axial direction A locking device that switches between a state, a front wheel non-drive state, and a front wheel double speed drive state is interposed.

And the present invention, by having such a configuration,
The above-mentioned problem is solved by locking the locking device in the middle of moving the hub linearly in the axial direction.

Example Next, an example of the present invention will be described with reference to the drawings.
In the drawings, a is an engine, b is a clutch housing, 11 is a mixing case, a main transmission section d is provided at a front portion of the mixing case 11, and a sub transmission section e and a front PTO section f are provided at an intermediate portion. And a PTO section g at the rear,
The pinion shaft 1 drives a rear axle i (only one is shown) via a rear wheel differential mechanism h, and a front wheel drive unit j has a front wheel differential mechanism k
Is interposed.

A gear 2 spline-fitted to the pinion shaft 1
Meshes with an idle gear 3 rotatably supported by a bearing 4 on a reduction shaft 5 as shown in FIG. 5 (b), and the idle gear 3 is engaged with a differential case 8 of the speed increasing differential mechanism m. It is fixed by bolts 7 and meshes with the input gear 6.

One boss 8a of the differential case 8 of the speed increasing differential mechanism m is supported by a holder 13 via a bearing 9,
Further, the other boss is extended rearward as a braking side boss 8b, and the rear portion is provided with a brake case via a bearing 10.
Mounted on 29, holder 13 and brake case 29 are bolt 1
The screw is screwed to the wall of the mixing case 11 by 2 and 28.

A pinion 18 is attached to a shaft 16 whose one end is fixed to a differential case 8 with a pin 21. The rear differential gear 20, which is spline-fitted so as to transmit to the front wheels and has a washer 19 interposed, is spline-fitted with a braking shaft 22 which is inserted into the braking-side boss 8b and is formed of a differential shaft. And stopped with a retaining ring 23.

As shown in FIG. 1, a large number of holes 24 are formed around the periphery of the braking side boss 8b of the input gear 6, and balls 25 fitted in the holes 24 are formed around the outer periphery of the braking shaft 22. A plurality of conical holes 27 corresponding to the balls 25 are provided so as to be disengaged.

A hub 26 slidably fitted on the outer periphery of the braking side boss 8b.
The ball 25 slides between the rear end of the differential case 8 and the bearing 10 by a fork 37 which has inclined surfaces 26a and 26b at both ends of the inner peripheral surface thereof and is engaged with the groove of the outer periphery.
And the ball 25 and the conical hole 27 fitted in the hole 24 constitute a locking device.

A retaining ring 34 is spline-fitted to the rear portion of the braking shaft 22,
A mating plate 32 provided inside the brake case 29 is fixed to the outer peripheral spline of the boss 30 fixed by 35, and a desk 31 combined with these is spline-fitted to the inner periphery of the brake case 29, and The hub 33, which is spline-fitted to the rear, slides forward and backward by the fork 43, and the fork 43, the hub 33, the desk 31, and the mating plate 32
Etc. constitute a braking mechanism.

Next, a fork 37 for sliding the hub 26 and a hub 33
The operation device with the fork 43 that slides the fork will be described. The fork 37 is slidably supported by a shifter shaft 38 parallel to the braking shaft 22, and the shifter shaft 38 is slidably supported by the wall of the mixing case 11 and the holder 13.
It is held by a bolt 40 so as not to rotate. The fork 43 is fixed to a rear portion of the shifter shaft 38 by a spring pin 44, and a boss 42 urged backward by a return spring 69 is fixed to a front portion of the fork 37 by a spring pin 41.

Further, an inner arm 39 whose tip is inserted into a groove formed in the boss of the fork 37 is fixed to the inner end of a cylindrical shaft 49 orthogonal to the shifter shaft 38 in the mission case 11, The cylindrical shaft 49 whose outer end is closed is fitted into the holder 46, and the outer portion has the spring pin 4 inserted through the holes 68 and 49a.
The boss 47a of the external link 47 is connected to the boss 47a by 8 and the inner end is received by the holder 46 by a retaining ring 59. The sliding shaft 51 fitted to the cylindrical shaft 49 has conical small diameter portions 63 and 64 near both ends thereof, and is urged by being pushed by an elastic machine 52 received by a spring pin 53. A boss 54 having an outer peripheral spline is rotatably fitted to a portion protruding from the holder 46 of 49, and an inner periphery corresponding to the outer peripheral spline is formed on the inner periphery of a cylindrical boss 55a in which a rotating link 55 is welded to the outer periphery. A peripheral spline is provided, and this cylindrical boss 55a is spline-fitted to the boss 54 and the inner end is fitted to the outer periphery of the holder 46,
In the assembling step, the cylinder shaft 49 is pushed out to the outside in a state where the retaining ring 59 is not attached, and the boss 47a of the external link 47 is fitted to the outer end of the cylinder shaft 49. , And the outer end side of the cylinder shaft is
It is connected to 49 so that it does not move in the axial direction. The cylinder shaft 49
And a conical small diameter portion inside the sliding shaft 51 of the holder 46
Holes 60 and 61 diametrically opposed to a portion corresponding to 63 are bored, and a pair of balls 62 and 62 are inserted therein. A cylindrical shaft 49 and a boss 54 at a portion corresponding to the outer conical small-diameter portion 64 are provided. Also hole 66,
A pair of balls 65, 65 are inserted by drilling 67, and between the boss 47a and the cylindrical boss 55a, between the cylindrical boss 55a and the holder 46, and between the holder 46 and the mission case 11, O-rings 56, 57, 58 are interposed therebetween to prevent oil leakage in the mixing case 11.

Further, a device for operating the external link 47 and the rotation link 55 will be described.
A switching lever 73 provided on the side of the driver's seat is interlockingly connected via 72, and a rotating link 55 is connected to a piston of a control hydraulic cylinder 75.
Both ends (only one is shown) of a double-acting hydraulic cylinder 79 which also serves as a tie rod for abutting 74 and steering the front wheels are mounted on a front axle 77 via a mounting 77a and mounted on the mounting 77a A restricting plate 80 screwed to the rod of the double-acting hydraulic cylinder 79 is opposed to the piston of the detected hydraulic cylinder 78, and the right and left detection hydraulic cylinders 78, 78 and the control hydraulic cylinder 5 are T-shaped. Are connected by a pipe 76.

In the agricultural tractor described above, when the switching lever 73 is set to the uppermost two-wheel drive position, the external link 47 moves to the 2W (I) position as shown in FIG. 10, and at this time AA in FIG. Sections (A), (B), and (C) of FIG. 6 are (I) in section, BB section, and CC section (the same applies hereinafter).
In this state, the fork 37 is in the hub state.
26 is located at the position shown in FIG.
22 rotates freely, and is in a two-wheel drive state in which the front wheels are not driven and are driven only by the rear wheels.

Next, when the switching lever 73 is pushed down to the middle 4WD position, the external link 47 moves to the 4W (II) position as shown in FIG. Are rotated as shown in the row (A) of FIG. 6 (A). At this time, the balls 62 and 65 are displaced as shown in the rows (B) and (C) of the row (II), and are integrated with the cylinder shaft 49. Inner arm 39 is fork 37
The hub 26 is moved from the position shown in FIG. 2 (a) to the position shown in FIG. 2 (b) on the left side of the hub 26, so that the front slope of the hub 26 pushes the ball 25 into the conical hole 27 and locks. As a result, a four-wheel drive state in which the front PTO shaft 36 is driven at a ratio of 1: 1 is established. At this time, the ball 62 rotates by the amount of play of the hole 61, which is a long hole in the circumferential direction, and is in contact with the end thereof.

When the switching lever 73 is further tilted downward and set to the lowest double speed position, the external link 47 is moved to the 4W double side (II
I) position, and the boss 47a and the cylinder shaft 49 at this time
As shown in (A) in the row of FIG. (III), the balls 62, 62 are rotated by the rotation of the cylindrical shaft 49 so that the inner peripheral ends of the holes 60 are formed as shown in (B) of the row in FIG. 6 (III). The hole 66 of the sliding shaft 51 coincides with the hole 67 of the boss 54 at the same time that the hole 66 of the sliding shaft 51 coincides with the hole 67 of the boss 54 by being pushed in by being rotated in the state of being received by the portion and pushing the slope of the conical small diameter portion 63 of the sliding shaft 51, On the other hand, the sliding shaft 51 moves to the right against the ammunition 52, and the outer balls 65, 65 are accordingly moved by the corresponding slopes of the conical small diameter portions 64 in the row (III) in FIG. C), the cylinder shaft 49 and the boss 54 are pushed out and locked, while the inner arm 39 which rotates integrally with the cylinder shaft 49 moves the fork 37 forward, and the hub 26 is moved as shown in FIG. It moves to the position shown by and maintains the 4WD state.

In this state, when the handle 81 is turned to one of them to operate the double-acting hydraulic cylinder 79 in order to turn the aircraft, the front wheel turns horizontally around the kingpin axis, and the regulating plate 80 detects the hydraulic pressure. The piston of the cylinder 78 is pushed in, and the piston of the control hydraulic cylinder 75 pushes and turns the rotation link 55 in conjunction therewith, so that the cylinder shaft 49 is shown in (B) and (C) of FIG. Thus, the spring pin 48 only rotates in the hole 68 which is a long hole in the circumferential direction, but does not rotate the boss 47a.
The inner arm 39 that rotates integrally with the inner arm 39 moves the hub 26 from the position shown in FIG. 2 (c) to the position shown in FIG. 2 (d) via the fork 37 at the initial stage.
Escapes from the conical hole 27 and the lock is released, so that the front PTO shaft 36 is not driven.At this time, when the base of the fork 37 contacts the boss 42 and the fork 37 continues to move forward, the shifter shaft 38 Also moves forward, the hub 26 moves to the position shown in FIG. 2 (e) to be in a two-wheel drive state, and the multi-plate clutch of the braking mechanism enters, so that the braking shaft 22 is stopped. The shaft 36 is rotationally driven at double speed, and the body turns at a so-called double speed.

When the handle 81 is returned and rotated at the end of the body turning, the double-acting hydraulic cylinder 79 operates in the opposite direction, and
When 80 moves away from the piston of the detection hydraulic cylinder 78, the piston and the piston of the control hydraulic cylinder 75 are respectively returned to the standby posture by the return springs provided therein, and the rotating link 55 is pulled back and returned by the return spring 55b biased thereto. Is moved, the cylinder shaft 49 returns and rotates,
The operation device 37 returns to the state shown in FIG. 6 (III), whereby the hub 26 is moved rearward to the second position.
After returning to the position shown in FIG. 4C through the position shown in FIG. 5D, the ball 25 is pushed in and locked in the process, and at the same time, the fork 43 is moved as the shifter shaft 38 moves backward. Since the hub 33 is returned to the rear, the lock of the braking mechanism is released, and the vehicle returns to the four-wheel drive state as described above.

When the switching lever 73 is tilted upward to the intermediate four-wheel drive position (II), the operating device of the fork 37 is in the state of the row of FIG. 6 (II), and at this time, the hub 26 is moved rearward in FIG. 4B, the four-wheel drive state is maintained. In this state, the sliding shaft 51 is pushed out by the spring 52 and the ball 65 Is fitted in the conical small diameter portion 64, so that even if the rotation link 55 rotates, the cylinder shaft 49 does not rotate, and the double-speed driving is not performed.

When the switching lever 73 is further tilted upward and set to the two-wheel drive position (I), the operating device of the fork 37 is in the state of the row in FIG. 6 (I), and the hub 26 is in the position shown in FIG. 2 (a). It becomes a two-wheel drive state because it retreats. 65a is a ball receiver.

[Effects] In summary, since the present invention is configured as described above, when the hub is located at the rear part, the lock of the locking device is released and the transmission to the front wheels is cut off, so the rear wheel drive is performed. When the hub is moved to the middle part, the locking device is locked and the front wheels are driven in a one-to-one ratio. When the hub comes off the locking device, the rear wheels are driven, and when the hub is further moved forward, the difference is obtained. The braking shaft of the driving device is braked and stopped, and the front wheels are driven at double speed.

When the hub is moved rearward from this state, the locking device is locked once after the rear wheel is driven, and the front wheels are driven one-to-one. When the hub is further moved rearward, the rear wheel is driven.

As a result, the front wheels can be easily switched to various driving states such as non-driving, driving, non-driving and double-speed driving by a simple reciprocating mechanism by a simple operation of linear movement in the axial direction of the hub. In addition, there is no possibility that the transmission is disabled due to the lack of the claws unlike the method of switching by the claws.

[Brief description of the drawings]

1 shows an embodiment of the present invention, FIG. 1 is a longitudinal sectional view of a speed-increasing differential mechanism, and FIGS. 2 (a) to 2 (e) are sectional views showing an operating state of a locking device. FIG. 3 is a plan view showing a partial cross section of the shift device, FIG. 4 is a cross sectional view of the shift portion operating device, FIG. 5 (a) is a development view of the mission case,
(B) is a development view of the front PTO transmission part, FIG. 6 (A) is an operation view of an AA cross section of FIG. 4, (B) is an operation view of a BB cross section of the same, and (C) is 7 is a side view of the agricultural tractor, FIG. 8 is a plan view of a front axle part, FIG. 9 is a sectional view of a hydraulic control part, and FIG. 10 is a view of an external link part. It is sectional drawing. In the figure, 8 is a differential case, 8b is a braking boss, 24 is a hole, 25 is a ball, 26 and 33 are hubs, 37 and 43 are forks, h and k are differential mechanisms, and m is a speed increasing operation mechanism. .

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Masanobu Itagaki 667 Iidacho, Higashiizumo-cho, Yatsuka-gun, Shimane Prefecture 1 Mitsubishi Agricultural Machinery Co., Ltd.

Claims (2)

(57) [Claims] 1. A differential mechanism (k) for a front wheel drive unit and a rear wheel drive unit, which are housed in a mission case (11), respectively.
(H), in a farming tractor in which a transmission system to the front wheel side differential mechanism (k) is further provided with a speed increasing differential mechanism (m), wherein the speed increasing differential mechanism (m) is provided. The braking side boss (8b) of the differential case (8) is formed in a cylindrical shape and long, and a hub (26) is fitted around the outer periphery of the braking side boss (8b) so as to be movable in the axial direction. A braking shaft (22) composed of a differential shaft is freely rotatably fitted on the inner periphery, while the braking shaft (2
2) and the case (11) between the brake shaft (2)
2) A braking mechanism for braking the front wheel to achieve the double speed driving state is provided, and between the braking boss (8b) and the braking shaft (22) in the axial direction of the hub (26). A turning device for an agricultural tractor, comprising a rocking device that switches between a front wheel non-driving state, a front wheel driving state, a front wheel non-driving state, and a front wheel double speed driving state based on movement. 2. A slope (26) is provided at both ends of the inner peripheral surface of the hub (26).
a, 26b), and the locking device is loosely fitted into a hole (27) formed in the peripheral surface of the braking shaft (22) and a hole (24) formed in the braking side boss (8b), The turning device according to claim 1, further comprising a ball (25) that switches a driving state by engaging and disengaging the hole (27).