JP2536487Y2 - Front wheel transmission for agricultural tractors - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to a front wheel transmission for an agricultural tractor performing various agricultural operations.

(B) Conventional technology Conventionally, a front wheel transmission mechanism is interlocked with a rear wheel transmission system and has a drive shaft having a pair of speed change drive gears, is transmitted to front wheels in parallel with the drive shaft, and meshes with the speed change drive gears. A large-diameter agricultural tractor comprising a driven shaft rotatably supporting a pair of transmission driven gears and a transmission switching means interposed between the transmission driven gears, wherein the front wheel is driven at substantially the same speed as the rear wheel. A clutch pawl is attached to each of the shift driven gear (straight drive system) and the small-diameter shift driven gear (rotating speed increasing system) that drives the front wheels faster than the rear wheels, and an occlusal shift member is interposed between them. What is JP-A-58-12223
It is already known from Japanese Patent Publication No. 0 and the like.

Also, a multi-plate clutch is attached to the shift driven gear of the turning drive system, a clutch pawl is attached to the shift driven gear of the straight drive system, and a shift member having an occlusal clutch pawl is interposed between them. This is already known from JP-A-62-137226.

(C) Problems to be Solved by the Invention Among the known front wheel transmissions in the tractor, the former is dangerous because the power intermittent means are all of the clutch pawl type, and is dangerous and the bite is not smooth. Was.
In addition, the front-rear width between the straight drive system and the turning speed-increasing system is widened, which increases the angle of the universal joint transmitting to the front wheels, making transmission less smooth and causing interference between the universal joint and the clutch housing. However, if the front wheel transmission is relocated downward to solve such problems, the tractor will have a lower ground clearance, causing the clutch housing to extend rearward and the wheel base to be longer.

In the latter, the shock at the time of switching the front wheels at high speed was reduced, but the other problems mentioned above were not solved.

(D) Means for Solving the Problems The present invention relates to a front wheel drive shaft 16 having a pair of speed change drive gears 20a and 20b in conjunction with a rear wheel transmission system.
A driven shaft 23 rotatably supporting a pair of transmission driven gears 24, 26 having a large diameter and a small diameter, which are transmitted to the front wheels in parallel with the front wheel driving shaft 16 and mesh with the transmission driving gears 20a, 20b, respectively. In the agricultural tractor constituted by the large-diameter transmission driven gear 24 and the transmission switching means interposed between the small-diameter transmission driven gear 26, the large-diameter transmission driven gear 24 is directed toward the small-diameter transmission driven gear 26. A plurality of through holes 24a are formed on the outer periphery of the extended boss, and a ball 28 is fitted into the through hole 24a and a conical hole 28a is provided on the outer peripheral surface of the driven shaft 23 facing the through hole 24a. The large-diameter transmission driven gear 24 side with respect to the small-diameter transmission driven gear 26 is disposed adjacent to the ball lock mechanism and has a wet multi-plate clutch 36.
A switching sleeve 30 serving as a speed change switching means for intermittently intermittently interposing the switching mechanism 30 between the wet multi-plate clutch 36 and the ball lock mechanism. The switching sleeve 30 has one end facing the ball lock mechanism. The inner peripheral portion is formed on a tapered surface 35 so as to guide the push-in of the ball 28 and prevent the ball 28 from jumping out. On the other hand, the outer end face of the other end facing the wet type multi-plate clutch 36 is formed as a pressing portion 37 for pressing the wet type multi-plate clutch 36 so that the speed change can be performed smoothly and the front wheel transmission device is provided. The above-mentioned problem has been solved by making it possible to narrow the front-back width.

(E) Operation When the switching sleeve is moved toward the large-diameter transmission driven gear (straight drive system) to travel straight, the ball lock mechanism is locked, and the front wheels are driven at substantially the same speed as the rear wheels. At this time, since the switching sleeve only performs the action of pushing the ball in the inner peripheral portion, the locked state can be extremely smoothly achieved.

When the switching sleeve is moved toward the small-diameter passive transmission gear (rotating speed increasing system) when the aircraft rotates, the ball lock mechanism is unlocked and the wet multi-plate clutch is engaged, so that the front wheel is engaged. The speed is changed to a higher speed more slowly than the bite type clutch.

Since a sleeve that fits on the outer periphery of the ball is interposed between the large and small passive transmission gears, the front and rear length of the front wheel transmission can be made shorter than that using an occlusal clutch as the transmission switching means. it can.

(F) Embodiment One embodiment of the present invention will be described with reference to the drawings. A dual clutch 2 is screwed to a flywheel of an engine 1,
The front ends of the inner transmission shaft 3 and the outer transmission shaft 4 loosely fitted on the outer periphery thereof are spline-fitted to the desks 5 and 6, respectively, and the rear portion penetrates through the clutch housing 7 to enter the transmission case 8, and the inner transmission shaft The transmission 3 is transmitted to the rear PTO transmission mechanism A, and the outer transmission shaft 4 is supported by the transmission case 8 and the case 11 by bearings 9 and 10, and is connected to the traveling transmission mechanism via the drive gear 12 spline-fitted thereto. It is transmitting.

A front portion of a front wheel drive shaft 16 connected to a pinion shaft 14 of a rear wheel differential by a joint 15 protrudes into the case 11, and is spline-fitted to this protruding portion, and is a double gear supported by bearings 17 and 18. Reference numeral 19 has a small-diameter transmission drive gear 20a, a large-diameter transmission drive gear 20b, and an oil hole 20c, and the rear of the driven shaft 23 supported by bearings 21 and 22, the transmission drive gear 20a.
A large-diameter transmission driven gear 24 meshing with
A small-diameter shift driven gear 26 meshed with the shift drive gear 20b
Is loosely fitted to a boss 25 which is spline-fitted to the front of the driven shaft 23, and a ball 28 fitted to a plurality of through holes 24a formed in the boss of the large-diameter transmission driven gear 24 and a driven shaft 23. A ball lock mechanism is formed by a conical hole 28a formed in an outer peripheral surface of the small-diameter transmission driven gear 26, and a wet multi-plate clutch 36 attached to the small-diameter transmission driven gear 26 is provided with a small-diameter transmission driven gear 26. A case 42 protruding from the side surface of the boss 25 and having a groove in the axial direction, a mating plate 43 having an outer peripheral portion fitted in the groove, and a spline fit to the outer peripheral surface on the rear side of the boss 25. , And a desk 40 which is superposed between the mating plates 43.

A switching sleeve 30 serving as a speed change switching means that slides back and forth by a fork 33 is interposed between the wet multi-plate clutch 36 and the ball lock mechanism.
Reference numeral 30 denotes a rear end inner peripheral portion which is formed by spline-fitting a boss 32 extending forward to the driven shaft 23, and which faces the ball lock mechanism extending toward the speed driven gear 24 having a larger diameter than the boss 32. Is formed on the tapered surface 35 acting on the outer periphery of the ball 28 to guide the pushing of the ball 28 and to prevent the ball 28 from jumping out, and the inner portion thereof is overlapped with the outer periphery of the boss of the large-diameter transmission driven gear 24 by overlapping. It is configured to be the pushing portion 30b of the ball 28. In addition, the wet multi-plate clutch 36 is provided outside the boss 32.
The outer end face of the other end opposed to is formed on a pressing portion 37 that presses the wet multiple disc clutch 36.

A recess 25a having a diameter larger than that of the driven shaft 23 is provided near the rear portion of the boss 25, and the spline portion 30a is projected forward from the inner peripheral portion of the switching sleeve 30 and inserted into the recess 25a. Therefore, the inner circumference of the rear end of the switching sleeve 30 is
The front and rear width of the switching sleeve 30 can be configured to be further narrowed in a state where the tapered surface 35 for preventing the push-in and pop-out is engaged with the driven shaft 23 by spline fitting.

The driven shaft 23 transmits power to the front wheel transmission section via a universal joint 47 at the front, the fork 33 is fixed to a shift rail 49 by a pin 50, and the front end of the shift rail 49 is inserted into a hole of the case 11. Along with the spring 52, it is pushed backward by a spring 52, and the rear end is pressed against the spherical concave portion of the piston 54 which is oil-tightly fitted to the cylinder portion 53, and is formed in the cylinder portion 53, and the oil passage 56 is pumped through an electromagnetic valve. It leads to the oilway of P.

The arm portion of the inner lever 59 is provided on the step portion 58 of the fork 33
The shaft portion 61 is rotatably and oil-tightly supported by the case 11, and the boss of the operation lever 65 is fixed to the outer end thereof with a pin 66.

67 and 68 are air release slits, and the operating lever 65 is press-fitted into any one of the concave portions 71, 72 and 73 of the lever guide 70 by a spring 69. In the transmission described above, when the operating lever 65 is fitted into the second driving recess 71 of the groove of the lever guide 70, the arm portion 60 comes into contact with the step portion 58 in FIG. The parallel shift rail 49 and the fork 33 are moved to the front wheel free position a, whereby the switching sleeve 30 is moved to the position shown in FIG. 1, that is, the ball lock mechanism is released, and the wet multi-plate clutch 36 is disengaged. Therefore, the transmission driven gears 24 and 26 are both rotatable and are not transmitted to the front wheels. When the operating lever 65 is shifted and fitted into the fourth drive recess 72 of the lever guide 70, the shift rail 49 and the like are moved to the front wheel drive position b in FIG.
Moves backward, and its tapered surface 35
28a, the transmission driven gear 24 and the driven shaft 23 are coupled so as to rotate integrally, so that the transmission driven gear 26 freely rotates, and the driven shaft 23 is connected to the front wheel 48 via the universal joint 47 and the front wheel differential. It is transmitted at almost the same speed.

When the operating lever 65 is fitted into the front wheel acceleration standby recess of the lever guide 70, the switch 74 is turned on, and the arm 60
Since the vehicle is tilted to the front wheel acceleration regular position c shown by a solid line in the figure and the shift rail 49 does not move, on the one hand, the switching sleeve 30 holds the above-mentioned four-wheel drive state in which the front wheels 48 are forcibly driven. In the figure, when the turning angle of the front wheel 48 becomes a predetermined angle by turning the steering wheel in a state where the switch 74 is turned on and the turning angle switch S is turned on, the electromagnetic valve 57 is energized. 7, the hydraulic oil pumped by the pump P in FIG. 7 is distributed to the oil passage 56, which is opposed to the spring 52 in FIG.
To the front (to the right in the figure)
33 and the switching sleeve 30, the switching sleeve 30 does not push the ball 28 in the first stage, so that the large-diameter shift driven gear 24 is unlocked to be in a two-wheel drive state,
When the shift rail 49 moves further forward, the switching sleeve 30
Press portion 37 causes the wet multi-plate clutch 36 to perform a braking operation, and the small-diameter transmission driven gear 26 rotates integrally with the driven shaft 23, so that the front wheel
48 rotates at high speed. Further, when the shift rail 49 is slid by hydraulic pressure, its end face may be used as a pressure receiving surface. The engine output loss can be minimized by P, and the lever operation is straight-line operation, and the handling is good.
It is desirable that the overlapping surface of the shift rail and the shift rail be a spherical surface as shown.

When the turning angle of the front wheels 48 is reduced to a predetermined value or less by turning the steering handle back after turning the body, the turning angle switch S is turned off, the electromagnetic valve 57 is switched, and the hydraulic oil in the oil passage 56 is After flowing out into the tank (the transmission case 8), the shift rail 49 returns to the fourth drive position b by the spring 52, and thus returns to the normal four-wheel drive state.

The front-wheel transmission shown in FIGS. 9 to 13 has a differential mechanism interposed in the transmission system for the front wheels, transmits power to the front wheels 48 by a differential shaft 78 in front of the transmission, and applies a wet multi-plate clutch to a differential shaft 79 in the rear. When the 80 is installed, the ball 75 that fits into the conical hole of the differential shaft 79 is inserted into the hole of the boss behind the differential case, and the switching sleeve 30 is moved forward to release the pushing of the ball 75. 48 is free rotation), and when it moves to the middle, the switching sleeve 30 pushes the ball into the conical hole and enters the four-wheel drive state where the differential case and the differential shaft 79 rotate integrally, and the switching sleeve 30 is moved a little further backward. When the turning angle switch is turned on in this state, the solenoid valve 57 is switched, and the hydraulic oil from the pump P moves the shift rail 49 rearward. Move to unlock by the ball and wet The multi-plate clutch 80 is braked to stop the rear differential shaft 79, so the front wheels 48
Is driven at a double speed. In the case 11, the switching sleeve 30 is provided with holes facing each other at the two-wheel drive position, and a pin 76 having a screw hole in the head is inserted thereinto. By inserting the tip into the circumferential groove of the switching sleeve 30 in the inserted state, the switching sleeve 30 can be positioned without removing the lubricating oil in the case 11, and when this is completed, the pin 76 is fixed to the washer. And the bolt 77 is used to maintain the non-operating position.

This positioning means positions the switching sleeve 30 in the above-described embodiment.

(G) Effect of the Invention As described above, the present invention relates to a front wheel transmission mechanism which is connected to a rear wheel transmission system and has a pair of speed change drive gears 20a and 20b. A driven shaft 23 rotatably supported by a pair of large-diameter and small-diameter driven gears 24 and 26 having a large diameter and a small diameter that is transmitted to the front wheels and meshes with the variable-speed drive gears 20a and 20b, respectively. In the agricultural tractor constituted by the shift switching means interposed between the shift driven gears 26, the large-diameter shift driven gear 24
A plurality of through holes 24a are formed on the outer periphery of the boss extending toward the small-diameter shift driven gear 26 side, and a ball 28 is fitted into the through hole 24a and the outer periphery of the driven shaft 23 facing the through hole 24a. A conical hole 28a is provided on the surface to form a ball lock mechanism, and a wet multi-plate clutch 36 is provided adjacent to the ball lock mechanism on the side of the large-diameter transmission driven gear 24 with respect to the small-diameter transmission driven gear 26. A switching sleeve 30 serving as a speed change switching means for intermittently connecting the wet multi-plate clutch 36 and the ball lock mechanism is interposed between the wet multi-plate clutch 36 and the ball lock mechanism. The switching sleeve 30 has an inner peripheral portion at one end facing the ball lock mechanism. The tapered surface
35 is formed to serve as a pushing guide for the ball 28 and to prevent the ball 28 from jumping out, and a deep portion thereof is externally fitted to the outer periphery of the boss of the large-diameter shift driven gear 24 to form a pushing portion for the ball 28.
Since the outer end face of the other end facing the wet type multi-plate clutch 36 is formed as a pressing portion 37 for pressing the wet type multi-plate clutch 36, the switching sleeve 30 serving as the speed change switching means has an inner peripheral portion at one end having a tapered surface 35. The inner part of the switching sleeve 30 is formed as a pushing part 30b, and the pushing part 30b of the switching sleeve 30 is fitted over the outer periphery of the boss of the large-diameter shift driven gear 24 as ball pushing means of a ball lock mechanism. Can be used as the pressing portion 37 of the wet-type multi-plate clutch 36, so that the speed changeover means can be only the narrow changeover sleeve 30, the interval between the speed change gear trains is reduced, and the case 11 The amount of forward projection can be reduced, and the transmission can be performed with the angle of the universal joint being proper without moving the driven shaft downward or extending the clutch housing 7 backward.

Further, while the front wheel is not accelerated rapidly when the speed is increased, the other power connecting / disconnecting means is a ball lock mechanism, so that the power can be connected / disconnected smoothly on that side.

[Brief description of the drawings]

1 shows an embodiment of the present invention, FIG. 1 is a sectional view of a front wheel transmission, FIG. 2 is a transmission system diagram of a traveling transmission, and FIG. 4, FIG. 4 is a cross-sectional view of the same, FIG. 5 is a perspective view of a speed change operation unit, FIG. 6 is a cross-sectional view of the same front wheel speed increasing standby unit, FIG.
Fig. 9 is the control circuit diagram, Fig. 9 is the side view of the agricultural tractor, Fig. 10
FIG. 11 is a cross-sectional view of a front-wheel transmission for illustrating a gearshift sleeve positioning device, FIG. 11 is a horizontal cross-sectional view of the same, FIG. 12 is a cross-sectional view of an assembly adjustment state, and FIG. It is. 7 ... clutch housing, 8 ... mission case,
16: Drive shaft, 19: Gear, 20a, 20b: Variable speed drive gear, 23: Driven shaft, 24: Large diameter variable speed driven gear, 26:
Small-diameter shift driven gear, 24a ... through-hole, 25 ... boss, 28
…… ball, 28a …… conical hole, 30 …… switching sleeve, 30b
... Pushing part, 35 .. Tapered surface, 36..

 ──────────────────────────────────────────────────続 き Continuing from the front page Examiner Koji Kamemaru (56) References JP-A-2-18120 (JP, A) JP-A-1-108826 (JP, U)

Claims (1)

(57) [Scope of request for utility model registration] 1. A front wheel drive shaft 16 having a pair of speed change drive gears 20a and 20b interlocking a front wheel transmission mechanism with a rear wheel transmission system.
A driven shaft 23 rotatably supporting a pair of transmission driven gears 24, 26 having a large diameter and a small diameter, which are transmitted to the front wheels in parallel with the front wheel driving shaft 16 and mesh with the transmission driving gears 20a, 20b, respectively. In the agricultural tractor constituted by the large-diameter transmission driven gear 24 and the transmission switching means interposed between the small-diameter transmission driven gear 26, the large-diameter transmission driven gear 24 is directed toward the small-diameter transmission driven gear 26. A plurality of through holes 24a are formed on the outer periphery of the extended boss, and a ball 28 is fitted into the through hole 24a and a conical hole 28a is provided on the outer peripheral surface of the driven shaft 23 facing the through hole 24a. The large-diameter transmission driven gear 24 side with respect to the small-diameter transmission driven gear 26 is disposed adjacent to the ball lock mechanism and has a wet multi-plate clutch 36.
A switching sleeve 30 serving as a speed change switching means for intermittently intermittently interposing the switching mechanism 30 between the wet multi-plate clutch 36 and the ball lock mechanism. The switching sleeve 30 has one end facing the ball lock mechanism. The inner peripheral portion is formed on a tapered surface 35 so as to guide the push-in of the ball 28 and prevent the ball 28 from jumping out. A front wheel transmission for an agricultural tractor, wherein the outer end face of the other end facing the wet multi-plate clutch is formed as a pressing portion 37 for pressing the wet multi-plate clutch.