JPH063695Y2 - 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 operating device for an agricultural tractor that rapidly turns a machine body with a small radius.

(B) Conventional Technology As a front wheel speed-increasing operation device for an agricultural tractor, a device in which an operation shaft is installed between opposite side walls of a mission case has been already known.

(C) Problems to be Solved by the Invention The operating device for the front wheel speed increasing device in the known agricultural tractor has a structure in which when the operating shaft is traversed in a transmission case in which various transmission mechanisms are installed, In order to prevent the transmission mechanism from interfering with the transmission case, the mission case becomes larger, and it is necessary to seal both end portions of the operation shaft and the two support portions of the mission case that support the operation shaft, which significantly increases the cost. It was

(D) Means for Solving the Problems The present invention relates to an agricultural tractor in which a differential mechanism is attached to the front wheel drive unit and the rear wheel drive unit, and a speed increasing device is interposed in the transmission system to the front wheels. A portion of the operating shaft that supports the operating shaft of the operating device for shifting the speed device and one end of the operating shaft enters the mission case, and the operating shaft projects outward from the mission case. When the two arms connected to the two operation systems were attached to the above, the above-mentioned problems could be solved.

However, since the operation shaft is supported only on one side wall of the mission case, if it is arranged on the side away from the arm mission case that is connected to the operation system having a strong operation force,
There is a new problem that the support of the operation shaft itself and the transmission of the operation force become unstable.

This problem was solved by disposing an arm that receives a strong operating force on the mission case side.

(E) Action By sealing the operating shaft of the operating device against one side wall of the mission case, it is possible to prevent oil leakage from the operating shaft mounting part of the mission case. When the arm is operated, manual switching such as 2WD or 4WD can be performed, and when the hydraulic system operates by steering to rotate the aircraft, the arm near the case receives a strong operating force to rotate and the front wheel The front wheels are accelerated through the speed increasing device.

At this time, since the arm that operates with a strong operating force is located near the mission case, the operating shaft does not tilt and the front wheel speed increasing device can be reliably switched.

(F) Embodiment An embodiment of the present invention will be described with reference to the drawings. In FIG. 5, a is an engine, b is a clutch housing, 11 is a mission case, and a main transmission unit is provided at the front of the mission case 11. d, a sub transmission portion e and a front PTO portion f are provided in the middle portion, and a PTO portion g is provided in the rear portion, and the pinion shaft 1 has a rear axle i (only one is shown) via a rear wheel differential mechanism h. And a front wheel drive mechanism j is provided with a front wheel differential mechanism k.

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

Then, one boss 8a of the differential case 8 of the speed increasing differential mechanism m is supported by the holder 13 via the bearing 9, and the other boss is extended rearward as a braking side boss 8b so as to be rearward. Through the bearing 10 to the brake case 29
The holder 13 and the brake case 29 are mounted on the bolt 12
., 28 ... are screwed to the wall of the mission case 11.

Pinion is attached to the shaft 16 whose one end is fixed to the differential case 8 with the pin 21.
18 and 18 are mounted, meshed with their front parts, and the rear end of the front PTO shaft 36 is spline-fitted as a differential shaft to the output differential gear 14 with the washer 15 interposed so as to transmit to the front wheels. Rear differential gear with washer 19
A braking shaft 22 formed of a differential shaft, which is fitted into the braking side boss 8b, is spline-fitted to 20 and is stopped by a retaining ring 23.

As shown in FIG. 3, a large number of holes 24, ... Are bored in the intermediate portion of the braking side boss 8b of the input gear 6, and the balls 25 ,. It is provided on the outer circumference so that it can be engaged with and disengaged from a large number of conical holes 27, ... Corresponding to the balls 25 ,.

The hub 26 slidably fitted to the outer periphery of the braking side boss 8b has slanted surfaces 26a and 26b at both ends of the inner peripheral surface thereof, and the fork 37 described later engages with the groove of the outer periphery to allow the rear of the differential case 8 The ball 25 that slides between the end and the bearing 10 disengages the ball 25 ... from the conical hole 27.
.. and the conical hole 27 .. .. constitute a locking device.

Retaining rings 34, 35 are fitted to the rear portion of the braking shaft 22 by spline fitting.
Brake case on the outer spline of the boss 30 fixed with
The mating plates 32, ..., which are installed inside the 29, are fixed, and the desks 31 ,. Sliding back and forth by 43, these forks 43, hub 33, desks 31, ..., Mating plate 32, etc. constitute a braking mechanism.

Next, the operation device of the fork 37 for sliding the hub 26 and the fork 43 for sliding the hub 33 will be described. The fork 37 is slidably supported by the shifter shaft 38 parallel to the braking shaft 22. The cage shifter shaft 38 is slidably supported by the wall body of the mission case 11 and the holder 13,
The fork 43 is held by a bolt 40 so as not to rotate, the fork 43 is fixed to the rear part of the shifter shaft 38 by a spring pin 44, and the front part of the fork 37 is biased to the rear through a return spring 69. Fix the boss 42 with the spring pin 41, and also return the spring between the holder 13 and the fork 37.
via a.

Further, an inner arm 39 having a tip end inserted into a groove of a boss portion of the fork 37 is fixed to an inner end of a cylinder shaft 49 serving as an operation shaft, and the cylinder shaft 49 is attached to one side wall of the mission case 11 by the shifter. The inner end side of the cylindrical shaft 49, which is supported by penetrating orthogonally to the shaft 38 and whose outer end is closed, has a spacer 46a on the inner end side and is fastened to the boss 46 by a retaining ring 59, and the outer portion is made into a long hole 68 and a hole 49a. The spring pin 48 inserted through the boss 47 of the outer arm 47
The sliding shaft 51, which is connected to a and is inserted into the cylindrical shaft 49, has conical small-diameter portions 63 and 64 in the vicinity of both ends, and is pushed by a bullet 52 that is received by a spring pin 53. Then, a spacer 54 having an outer peripheral spline is rotatably fitted to the portion of the cylindrical shaft 49 protruding from the boss 46, and the speed increasing arm is provided.
An inner peripheral spline corresponding to the outer peripheral spline is provided on the inner periphery of the cylindrical boss 55a projecting on the outer periphery of 55, and this cylindrical boss 55a is spline fitted to the spacer 54 and the inner end of the boss 46 is formed. In the assembly process, the cylinder shaft 49 is pushed out to the outside in a state where the retaining ring 59 is not attached in the assembly process, and the boss 47a of the outer arm 47 is fitted to the outer end portion of the cylinder shaft 49, and the opening is formed. Part side is brought into contact with the spacer 54,
As described above, the outer end side is connected to the cylindrical shaft 49 by the spring pin 48 so as not to move in the axial direction. The cylinder shaft 49 and the boss
A hole 60 and a long hole 61 in the circumferential direction, which are opposed to each other in the diametrical direction, are formed in a portion of the sliding shaft 51 corresponding to the conical small-diameter portion 63 inside the sliding shaft 51, and a pair of balls 62, 62 are fitted and inserted. , The outer conical small-diameter portion 64 and the portion corresponding to the cylindrical shaft and the spacer 54 have holes 66, 6
A pair of balls 65, 65 are fitted and inserted by drilling 7 and between the boss 47a and the cylindrical boss 55a, and between the cylindrical boss 55a and the boss 4.
O-rings 56, 57 and 58 are respectively provided between the O-ring 58 and the boss 46 and between the boss 46 and the mission case 11 to prevent oil leakage in the mission case 11 together with the O-ring 58.

Further, a device for operating the outer arm 47 and the speed increasing arm 55 will be described.
Via a switching lever 73 provided on the side of the driver's seat via the
Both ends (only one of which is shown) of the double-acting hydraulic cylinder 79 that also serves as a tie rod for steering the front wheels are attached to the front axle 77 via the attachment metal 77a.
A regulating plate 80 screwed to the rod of the double-acting hydraulic cylinder 79 is opposed to the piston of the detecting hydraulic cylinder 78 attached to the 7a, and the detecting hydraulic cylinders 78, 78 on the left and right are connected to the pipe 76a.
, And one of the detection hydraulic cylinder 78, the control hydraulic cylinder 75, and the pipe 76 are connected. In addition, the guide plate 73a of the switching lever 73 is provided with a guide groove having a three-step engagement cutout portion on its side, and the boss of the switching lever 73 has a support shaft 73b and a braking spring 73c interposed therebetween. It is attached by a retaining ring in the state of.

In the above-mentioned agricultural tractor, when the switching lever 73 is set to the uppermost two-wheel drive position (I), the operating device of FIG. 1 has the operating device of FIG. 6 taken along the line AA, the line BB, and the line C-C (hereinafter In the same manner), row (I) is in the state of A, B, C. In this state, the fork 37 and the hub 26 are at the positions shown in FIG. This means that the front wheels are not driven and only the rear wheels are driven, resulting in a two-wheel drive state.

Next, when the switching lever 73 is pushed down to the intermediate 4WD position (II), the boss 47a moves the cylinder shaft 49 to the sixth position via the spring pin 48.
When the balls 62 and 65 are rotated as shown in (II) row A in the figure, the balls 62 and 65 are displaced as shown in (II) row B and C, and the inner arm 39 integrated with the tubular shaft 49 is connected to the hub 26 via the fork 37. 2 is moved from the position (a) in FIG. 2 to the position (b) on the left side thereof, the front slope of the hub 26 pushes the balls 25 ... into the conical holes 27. It is in a four-wheel drive state in which the shaft 36 is driven at a ratio of 1: 1. At this time, the ball 62 is rotated by the amount of the play of the elongated hole 61 in the circumferential direction and is in contact with the end portion thereof.

Tilt the switching lever 73 further downward to move to the lowest speed position (I
When set to (II), the boss 47a of the outer arm 47 and the cylinder shaft 49 rotate like A in the (III) row, and the rotation of the cylinder shaft 49 causes the balls 62, 62 to move to B of (III). As shown, the sliding shaft is pushed in by being rotated while being received by the inner peripheral end portion of the long hole 61, and the slant surface of the conical small diameter portion 63 of the sliding shaft 51 is pushed at the same time as the sliding shaft.
Since the hole 66 of 51 coincides with the hole 67 of the spacer 54, on the other hand, the sliding shaft 51 moves to the right against the ammunition 52, and the outer balls 65, 65 accordingly have a corresponding conical small diameter. The inclined surface of the portion 64 pushes the cylinder shaft 49 and the spacer 54 out as shown by C in (III), and on the other hand, the cylinder shaft 49
The inner arm 39 that rotates together with the fork 37 moves the fork 37 forward, and the hub 26 moves to the position (c) in FIG. 4 to maintain the four-wheel drive state.

In this state, if the handle 81 is turned to one of the two to actuate the double-acting hydraulic cylinder 79 in order to turn the machine body, the front wheels turn horizontally about the gold pin axis, and accordingly the regulation plate 80 detects the detected hydraulic pressure. Cylinder 78 piston
78a is pushed in, and the piston 74 of the control hydraulic cylinder 75 pushes the speed-increasing arm 55 to rotate in conjunction therewith,
The cylindrical shaft 49 rotates as shown in B and C of the (IV) row, and the spring pin 48 rotates the boss 47a only by rotating in the elongated hole 68 which is an elongated hole in the circumferential direction. Instead, the inner arm 39 that rotates integrally with the cylinder shaft 49 has the fork 37
The hub 26 is moved from the position (c) to the position (d) in FIG. 4 via the ball, and the ball 25 slips out of the conical hole 27 and the lock is released, so that the front PTO shaft 36 is not driven. 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, and the hub 26 moves to the position (e) in FIG. Since the multi-plate clutch of the braking mechanism is turned on and the braking shaft 22 is stopped, the front PTO shaft 36 is rotationally driven at a double speed, and the airframe turns at a so-called double speed.

Further, when the handle 81 is returned and rotated at the end of the turning of the machine body, the double-acting hydraulic cylinder 79 operates in the opposite direction and the regulating plate 80 separates from the piston of the detection hydraulic cylinder 78. Are returned to the standby position by the return springs respectively installed therein, and the speed increasing arm 55 is pulled back and rotated by the return spring 55b attached thereto, so that the cylinder shaft 49 is rotated back and the operating device of the fork 37 is moved to the sixth position. After returning to the state of the (III) row in the figure, the hub 26 moves rearward and returns to the (c) position via the (d) position in FIG. 4,
In the process, the ball 25 is pushed in and locked, and at the same time, the fork is moved as the shifter shaft 38 moves rearward.
Since 43 returns the hub 33 to the rear, the control mechanism is unlocked and returns to the same four-wheel drive state as described above.

Further, when the switching lever 73 is tilted upward to the intermediate four-wheel drive position (II), the operating device of the fork 37 is brought into the state of row (II) in FIG. 6, and the hub 26 is moved to the rear (b) position. Since it is in the locked state, the 4WD state is maintained, and even if the handle is rotated a lot in this state, the sliding shaft 51 is pushed out by the bullet 52 and the ball 65 is fitted into the conical small diameter portion 64. Therefore, even if the speed increasing arm 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 boss 47a of the outer arm 47 is moved to (II) in FIG.
Although the state returns from (A) to (I) and (A), the spring pin 48 joins the elongated hole 68 of the boss 47a, so that the spring pin 48 returns to the positions shown in (I) and (A). Absent. When a return spring is attached to the speed increasing arm 55 in order to return and rotate this, the spring pin 48 returns and rotates via the spacer 54 and the cylinder shaft 49.

However, if the return spring is provided outside, it will rust or fall off. Such a problem is the holder 13
By inserting the return spring 69a between the fork 37 and the boss of the fork 37, the hub 26 can bear the shifter shaft 38.
It can be pushed back until it abuts 10 (the state shown in FIG. 4 (a)), whereby the inner arm 39 turns back and the tubular shaft 49 also turns back and the spring pin 48 is turned.
Returns to the predetermined position. In this case, the return spring 69
a does not rust or fall off.

That is, the operating device is in the state of row (I) in FIG.
Since 26 retreats to the position (a) in Fig. 4, it is in a two-wheel drive state.

(G) Effect of the device Since the device of the present invention is configured as described above, it suffices to insert the operating part of the operating shaft into the mission case, and it is less likely to interfere with various transmission devices in the mission case.
It is possible to reduce the weight and cost by preventing the mission case from becoming large.

In addition, the operation shaft is supported only by one side wall of the mission case, and the portion projecting to the outside receives the operation force of two systems, but the arm on the mission case side receives a large operation force from the hydraulic device. Since the operation shaft is received, the operation shaft can be supported in a stable state, and the front wheel drive device can be accurately shifted.

[Brief description of drawings]

The drawings show one embodiment of the present invention. FIG. 1 is a sectional view of a shift portion operating device, FIG. 2 is a plan view showing a partial cross section of the shifting device, and FIG. Longitudinal section of the mechanism,
FIG. 4 is a sectional view showing the operation of the lock device, FIG. 5 (a) is a development view of the mission case, (b) is a development view of the front PTO transmission portion, and FIG. 6 (A) is A of FIG. -A sectional view of the section, (B) same as above BB sectional view of the sectional view, (C) same as above CC sectional view of the sectional view, Figure 7 is a side view of the agricultural tractor, Figure 8 is FIG. 9 is a plan view of the front axle portion, FIG. 9 is a sectional view of the hydraulic control portion, and FIG. 10 is an exploded perspective view of a switching lever mounting portion. 8: differential case, 8b: braking side boss, 24: hole, 26,3
3 ... Hub, 37, 43 ... Fork, m ... Accelerating mechanism, 47 ... External arm, 49 ... Cylindrical shaft, 55 ... Accelerating arm, 55a ... Cylindrical boss

Claims (1)

[Scope of utility model registration request] Claim: What is claimed is: 1. An agricultural tractor having a front wheel drive section and a rear wheel drive section provided with a differential mechanism, wherein a transmission system for the front wheels is provided with a speed increasing device. The operation shaft is supported on one side wall of the mission case 11 so that one end of the operation shaft enters the mission case 11.
The other end of the operation shaft projecting outward from the mission case 11 has an arm connected to the manual operation system on the outside and an arm connected to the hydraulic operation system on the mission case 11 side for agricultural use. Front wheel speed increasing device for tractor.