JPH078004A - Agricultural work vehicle - Google Patents

Abstract

PURPOSE:To enable stable switching operation of a fork shaft using a small- sized inexpensive cam. CONSTITUTION:A transmission case 3 is provided with a fork shaft 45 for speed changing operation having speed changing operation cams 49, 50. The fork shaft 45 is slid by the rotary operation of the cams 49, 50 to change the speed in >=3 stages. A flat part 57 is formed between the slopes of the cams 49, 50 corresponding to the speed changing position of the middle speed changing stage.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an agricultural work vehicle equipped with a rotary working machine and used for cultivating work or the like.

[0002]

2. Description of the Related Art Conventionally, there has been a technique for providing a multi-stage forward and reverse output with a main transmission mechanism and an auxiliary transmission mechanism in a traveling mission of a general-purpose management machine.

[0003]

In the prior art, when a fork shaft for gear shift operation is attached to a mission case and a rotary cam for sliding the fork shaft is provided, the cam floor with which the rotary cam abuts is inclined continuously. Since it is formed on the surface, it is necessary to provide the rotary cam operating mechanism with a positioning member that stops the rotary cam at a midway shift stage in a structure that shifts at three or more stages. There was a problem that workability could not be improved easily.

[0004]

SUMMARY OF THE INVENTION However, according to the present invention, a gear shift operation cam is provided on the gear shift operation fork shaft provided in the transmission case, and the fork shaft is slid by the rotation operation of the cam to perform the gear shift of three or more steps. Configured to do
A flat portion is provided between the inclined portions of the cam in correspondence with the shift position of the intermediate shift stage. Since the flat portion can position the cam at the intermediate shift stage, special positioning for the cam is possible. Since it is not necessary to provide a member, it is possible to easily improve the workability such as simplification of the cam operation structure and assembly adjustment, and it is possible to stably perform the shifting operation of the fork shaft of three or more stages by the cam.

[0005]

Embodiments of the present invention will now be described in detail with reference to the drawings. 1 is an explanatory view of an auxiliary transmission mechanism portion, FIG. 2 is a side view of a management machine, FIG. 3 is a plan view thereof, FIG. 4 is an explanatory view of a mission case upper portion, FIG. 5 is an explanatory view of a lower portion thereof, and FIG. 6 is a main transmission mechanism. 7 is a side view of the upper part of the mission case, in which (1) is an engine, (2) is an engine stand on which the engine (1) is mounted, (3) is the engine stand (2) on the front side. A transmission case fixed to the transmission case, (4) a pair of left and right traveling wheels mounted on both sides of the transmission case (3) via axles (5), and (6) attached to the transmission case (3) via a hitch (7). Rotary work machine to be connected by traction,
(8) is a steering handle which is connected to the upper part of the mission case (3) through a handle base (9), and (10).
Is a main speed change lever supported on the mission case (3) so as to be swingable forward and backward, (11) is an auxiliary speed change lever provided on the steering handle (8), (12) is a pair of left and right side clutch levers, and (13) ) Is a traveling clutch lever, which is provided between the output pulley (14) of the engine (1) and the input pulley (15) of the transmission case (3) via the traveling clutch tension roller (16).
7) is stretched, the output of the engine (1) is transmitted to the mission case (3), and the rotary pawl (18) of the rotary working machine (6) is rotated to perform plowing work. .

Further, as shown in FIGS. 4, 6 and 7, an input shaft (21) provided with an input pulley (15), a main transmission gear (19) and a PTO output pulley (20), and a shift fork (22). A fork shaft (23) for sliding a main transmission gear (19) through a counter shaft, a counter shaft (25) provided with a reverse gear (24), first forward speed and second speed gear (26)
The main gear shaft (28) provided with (27) is rotatably supported by the transmission case (3), and the first gear (26) which is rotatably rotatably supported by the main gear shaft (28) is provided on the counter shaft (25). 29) and (30) are connected, and the counter shaft (2
5) to the main transmission shaft (28) counter gear (31) (3
2) to form a main transmission mechanism (33) having two forward gears and one reverse gear. The main gear shift lever (10) is connected to the fork shaft (23) through the shift arm (34). The reverse gear (24), the first gear (26) or the second gear (27) is operated to operate the main shift lever (10) for selectively meshing the shift gear (19).

Further, as shown in FIGS. 1, 4 and 6, low, medium and high speed gears (38) (39) (40) can be engaged and disengaged via ball clutches (35) (36) (37). The auxiliary transmission shaft (41) provided is pivotally supported on the transmission case (3), and the gears (38) to (40) are connected to the main transmission shaft (28).
The low, medium and high speed output gears (42), (43) and (44) are always meshed, and the fork shaft (45) is slidably inserted into the axial center position of the auxiliary speed change shaft (41), so that each ball clutch ( 35) to (37) for selectively engaging the shifter (4
6) is provided on the fork shaft (45) to form a three-step auxiliary transmission mechanism (47) for low, medium and high speed.
5) is slid in the axial direction to displace the shifter (46), and the low, medium and high speed gears (38) to (40) are connected to the auxiliary transmission shaft (41) via the ball clutches (35) to (37). ) Is selectively engaged to switch the output between low speed, medium speed, and high speed.

Further, as shown in FIGS. 1, 4, 7, 8 and 9, a compression spring (48) is wound around one end of the fork shaft (45), and the other end of the fork shaft (45) is closed. The end of the transmission case (3) is provided so as to project in and out of the transmission case (3), and a cylindrical fixed cam (49) and a rotating cam (50) are provided.
Attach the fixed cam (49) via the fixed cam (49)
A rotary cam (50) is inserted through a screw (52) and a nut (53) at an end of a fork shaft (45) through which a central portion is loosely fitted and inserted.
Rotatably attached to the rotary cam (50) by integrally fixing the auxiliary gearshift arm (54) to the auxiliary gearshift lever (1).
1) via an auxiliary transmission wire (55) and a return spring (55a) connected to the arm (54), and a low, medium and high speed cam floor flat surface (of a fixed cam (49) formed in multiple stages ( The cam flat surface (59) of the rotary cam (50) is made to face 56, 57, and 58, and the rotary cam (50) is rotated around the fork shaft (45) by the operation of the auxiliary speed change lever (11). The cam flat surface (59) is selectively brought into contact with any of the flat surfaces (56) to (58) of the medium- and high-speed cam floors to advance the fork shaft (45) against the compression spring (48), and also the spring. The fork shaft (45) is retracted by (48), and the low, medium and high speed output switching is performed by the shifter (46).

Further, as shown in FIGS. 4, 5, and 7, a sprocket (60) is integrally formed on the sub-transmission shaft (41), and ball clutch type side clutches (61) (6).
The sprocket (63) is pivotally supported on the axle (5) via the (2), and each sprocket (60) (63) is attached to the chain (6).
4) and the side clutch (6
1) Side clutch arms (67) and (67) for turning off (62) against springs (65) and (66) are provided, and the side clutch lever (12) is provided with a side clutch wire (68) via a side clutch wire (68). The clutch arm (67) is connected, and the side clutches (61) (62) are disengaged by operating the lever (12).

As is apparent from the above, fixed and rotating cams (49) and (50), which are speed change operation cams, are provided on the speed change operation fork shaft (45) provided in the mission case (3), and the cams (49) (). The fork shaft (45) is slid by the rotation operation of (50) to perform three or more gear shifts, and the inclinations of the cams (49) (50) corresponding to the gear shift positions of intermediate gears. The cam floor flat surface (57) which is a flat portion is provided between the parts, and the rotary cam (50) is brought into contact with the flat surface (57) of the cam floor to make the rotary cam (50) in the middle of the shift stage. The compression spring (in the state where the positioning is performed and the ball cam (36) of the medium speed gear (39) is engaged by the shifter (46) by the contact between the rotary cam (50) and the flat surface (57). 48) against Constitute over click shaft (45) so as to advance the support.

Further, the flat surface (5) of the medium speed cam floor is used.
By gently inclining 7) toward the flat surface (56) of the low speed cam floor, the force of the compression spring (48) acts as the return force of the rotating cam (50), and therefore the return spring (55).
a) Even if the force is reduced, the return movement of the sub-transmission arm (54) can be surely performed by the force of the spring (55a) and the force of the compression spring (48). ) Can be formed compactly.

[0012]

As is apparent from the above embodiments, according to the present invention, the shift operation fork shaft (45) provided in the transmission case (3) is provided with the shift operation cams (49) (50).
By rotating the cam (50), the fork shaft (45)
And the cam (4) corresponding to the shift position of the intermediate shift stage.
9) A flat portion (57) is provided between the inclined portions of (50), and the flat portion (57) can position the cam (50) at an intermediate shift speed. Therefore, the cam (49) (5)
It is not necessary to provide a special positioning member for 0),
In addition to simplifying the operation structure of the cams (49) (50) and improving workability such as assembling and adjusting, 3
The shift operation of the fork shaft (45) having more than the gears
9) It can be stably performed by (50).

[Brief description of drawings]

FIG. 1 is an explanatory diagram of an auxiliary transmission mechanism section.

FIG. 2 is a side view of a management machine.

FIG. 3 is a plan view of the same.

FIG. 4 is an explanatory diagram of the upper part of the mission case.

FIG. 5 is a lower part explanatory view of the same.

FIG. 6 is an explanatory diagram of a main transmission mechanism section.

FIG. 7 is a side view of the upper part of the mission case.

FIG. 8 is an exploded view of an auxiliary shift cam portion.

FIG. 9 is an explanatory diagram of the same development.

[Explanation of symbols]

 (3) Mission case (45) Fork shaft (49) Fixed cam (shift operation cam) (50) Rotating cam (shift operation cam) (57) Cam floor flat surface (flat portion)

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hiroaki Kaihara Akira Kawashima Shibaura Machinery Co., Ltd. 5-32-7 Sendagaya, Shibuya-ku, Tokyo

Claims (1)

[Claims] 1. A shift operation fork shaft provided in a transmission case is provided with a shift operation cam, and the fork shaft is slid by a rotational operation of the cam to perform a shift of three or more steps, and a shift in the middle. An agricultural work vehicle characterized in that a flat portion is provided between the inclined portions of the cam corresponding to the gear shift position of the gear.