JPH07277017A - Power extraction structure of tractor - Google Patents

Abstract

(57) [Abstract] [Purpose] To prevent the improper movement of the airframe due to the inertial rotational force of the attachment driven by the PTO shaft, and to quickly prevent the inertial rotation itself of the attachment itself. [Structure] In the power take-out structure of a tractor in which a one-way clutch 15 which allows the PTO shaft 9 to rotate in advance is interposed in a transmission system to the PTO shaft 9, a one-way clutch 15
Is a jump clutch composed of a drive-side clutch piece 17 loosely fitted to a fixed position of the PTO shaft 9 and a passive-side movable clutch piece 18 externally fitted and supported on the PTO shaft 9 so as to be torque-transmittable and shiftable. , A spring 19 for urging the movable clutch piece 18 in a direction to engage the drive side clutch piece 17, and a brake mechanism 21 between the PTO shaft 9 and the case 13 are provided.
Is configured to be braked by the movable clutch piece 18 which is displaced backwards against the spring 19.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power take-out structure for a tractor in which a one-way clutch that allows the PTO shaft to rotate in advance is interposed in a transmission system for driving the attachment such as a mower.

[0002]

2. Description of the Related Art The above-mentioned one-way clutch is provided in order to prevent the traveling system from being driven by the inertial rotational force of the attachment when the main clutch is disengaged to stop the aircraft. It is provided, and a jump clutch type and other types are appropriately selected and used [JP-A-2-28022].

[0003]

The provision of the above-mentioned one-way clutch prevents the inertial rotational force of the attachment from being transmitted to the traveling system, but the inertial rotation of the attachment itself is continued. there were. The present invention has been made paying attention to such a situation,
It is an object of the present invention to prevent undesired movement of the airframe due to the inertial rotation force of the attachment and also to quickly prevent the inertial rotation itself of the attachment itself.

[0004]

The characteristic structure of the present invention for achieving the above object is a power take-out structure for a tractor in which a transmission system to the PTO shaft includes a one-way clutch that allows the PTO shaft to rotate in advance. In the jump clutch, the one-way clutch includes a drive-side clutch piece loosely fitted to the PTO shaft at a fixed position and a passive-side movable clutch piece that is externally fitted and supported on the PTO shaft so as to be torque-transmittable and shiftable. In addition to the above structure, the PTO shaft is equipped with a coil spring for urging the movable clutch piece in the direction of engaging with the drive side clutch piece, and the brake mechanism is provided between the PTO shaft and the case. The point is that braking is performed by the movable clutch piece that is displaced backwards against the coil spring.

[0005]

According to the above construction, when the main clutch is disengaged, the one-way clutch of the jump clutch structure works to interrupt the power transmission from the PTO shaft to the traveling system due to the inertial rotation of the attachment. Further, the brake mechanism is operated by the operation in which the movable clutch piece of the one-way clutch shifts away from the drive side clutch piece, so that the PTO shaft is braked.

[0006]

According to the present invention, therefore, the one-way clutch can be used to prevent the aircraft from unduly moving due to the inertial rotational force of the attachment when the main clutch is disengaged, and the operation of this one-way clutch can be effectively utilized. As a result, the inertial rotation of the attachment itself can be quickly blocked, and safety can be improved.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a gear train having a transmission structure installed in a transmission case M of a tractor.

The engine output is transmitted to the input shaft 1 via a main clutch (not shown), and this power is transmitted to the main gear transmission mechanism 2.
After being transmitted to the intermediate shaft 3 via the auxiliary gear transmission mechanism 4, it is transmitted to the final transmission shaft 5 via the auxiliary gear transmission mechanism 4, and the bevel pinion gear P
It is transmitted to the rear wheel differential mechanism 6 via G. Also, from the output branch gear G6 provided on the final transmission shaft 5 to the shift gear SG
The power taken out via 6 is transmitted to the front wheel differential mechanism (not shown) via the front wheel transmission shaft 7 so as to be propelled by four-wheel drive.

The main gear speed change mechanism 2 includes speed change gears G1, G2, G3 fixed to the input shaft 1 and three shift gears SG1, SG2, SG spline-fitted to the intermediate shaft 3.
3 is composed of 3 and shift gear SG1 is shifted to the right to be engaged with transmission gear G1 to achieve the first forward speed, and shift gear SG2 is shifted to the left to be engaged with transmission gear G2 to provide the second forward speed. By shifting the shift gear SG3 to the right and engaging the gear G3 for shifting, the third forward speed is obtained, and further shifting the shift gear SG1 to the left to engage the idle gear IG1 loosely fitted to the front wheel transmission shaft 7. As a result, the first reverse speed can be obtained. The idle gear IG2 integrated with the idle gear IG1 is always meshed with the speed change gear G2.

The sub-gear transmission mechanism 4 comprises transmission gears G4 and G5 fixed to the intermediate shaft 3 and a pair of shift gears SG4 and SG5 spline-fitted to the final transmission shaft 5, and the shift gear SG4 is moved to the right. Shift and shift gear G
By engaging the 4th gear, the low speed is reduced, and the shift gear SG5
High speed is obtained by shifting the gear to the left and engaging with the gear G5 for shifting, and by combining the gear shifting of the main gear shifting mechanism 2 and the sub gear shifting mechanism 4, multi-speed shifting of 6 forward gears and 2 reverse gears is possible. It is possible, and the front wheels that receive the branch power from the final speed change shaft 5 are also configured to change gears in synchronization with the rear wheels. Incidentally, when the shift gear SG6 is shifted to the right to release the engagement with the output gear G6, the transmission to the front wheels is cut off and the propulsion is performed only by the rear wheels.

The mission case M of this tractor is equipped with a rear PTO shaft 8 for driving an attachment such as a rotary tiller and an intermediate PTO shaft 9 for driving a mid-mount type mower.

The rear PTO shaft 8 is projected rearward at the rear of the transmission case M, and the power branched from the input shaft 1 is used as the first PTO transmission shaft 10, the second PTO transmission shaft 11, and the reduction gear G7. , P8 via G8
It is transmitted to the shaft 8 and driven at a constant speed irrelevant to the traveling system. That is, the first PTO transmission shaft 10
A shift gear SG7 which can be disengaged from the transmission gear G2 of the input shaft 1 is spline-fitted to the first P
The TO transmission shaft 10 and the second PTO transmission shaft 11 are concentrically interlocked via a jump clutch type one-way clutch 12, and the rotation of the second PTO transmission shaft 11 is reduced by a reduction gear G7,
It is configured to be transmitted to the rear PTO shaft 8 via G8.

The intermediate PTO shaft 9 is supported by an output case 13 attached to the lower abdomen of the transmission case M and protrudes forward, and the power branched from the input shaft 1 is transmitted to the transmission gear G3 and the first PTO transmission. A first intermediate gear G9 loosely fitted to the shaft 10 and a second intermediate gear G loosely fitted to the fixed intermediate shaft 16.
10, the passive gear G11 loosely fitted to the intermediate PTO shaft 9, the gear clutch 14, and the one-way clutch 15 are transmitted to the intermediate PTO shaft 9 so that the intermediate PTO shaft 9 is driven at a constant speed irrelevant to the traveling system. Has become.

The one-way clutch 15 is composed of a driving side clutch piece 17 loosely fitted to the intermediate PTO shaft 9 and a passive side movable clutch piece 18 spline-fitted to the intermediate PTO shaft 9. Each of them is occluded with each other via the occlusal portions 17a and 18a formed in the opposing portion, and the movable clutch piece 18 is urged in the occlusal direction by the weak spring 19 fitted and fitted on the intermediate PTO shaft 9, and
When the movable clutch piece 18 rotates ahead of the drive side clutch piece 17, the engagement parts 17a and 18a are arranged so that the movable clutch piece 18 is displaced backwards against the spring 19 in the direction away from the drive side clutch piece 17. It is a structure having an inclined cam surface, that is, a so-called known jump clutch structure.

The gear clutch 14 transmits the power to the one-way clutch 15 by spline-fitting the shift sleeve 20 over the boss portion of the drive side clutch piece 17 and the boss portion of the passive gear G11 to shift the gear. The sleeve 20 is shifted to the right in the drawing to be disengaged from the boss portion of the passive gear G11 so that the power transmission to the one-way clutch 15 is released.

At the rear portion of the intermediate PTO shaft 9, a group of friction plates 21a engaged with the output case 13 and an intermediate PTO shaft are provided.
A multi-plate type brake mechanism 21, which is formed by alternately superimposing groups of friction plates 21b engaged with the shaft 9, is mounted. A strong spring 22 is interposed between the brake mechanism 21 and the movable clutch piece 18 of the one-way clutch 15. The spring 22 is set to have a dimension such that it has a free length when the one-way clutch 15 is in the occlusal state.
When is displaced backwards against the spring 19, the spring 22 is pressed and deformed to elastically press the brake mechanism 21 to exert a braking action.

Therefore, while the mower is driven by the intermediate PTO shaft 9, the spring 22 is in the free length state and the brake mechanism 21 is in the braking release state as shown in FIG. When the main clutch is disengaged while driving the mower, as shown in FIG. 3, the intermediate PTO shaft 9 is rotated by the inertia of the mower with respect to the passive gear G11 which is about to be stopped by the load of the traveling system. Attempts to continue, and as a result, the movable clutch piece 18 of the one-way clutch 15 is displaced backwards against the spring 19 to cut off the power transmission to the intermediate PTO shaft 9, and with the backward displacement of the movable clutch piece 18. The brake mechanism 21 is operated to exert a braking action on the intermediate PTO shaft 9.

In the embodiment, the case where the brake mechanism 21 is acted only on the intermediate PTO shaft 9 is illustrated, but the rear PTO shaft 9 is used.
A similar brake mechanism 21 may be applied to the shaft 8.

It should be noted that reference numerals are given in the claims for convenience of comparison with the drawings, but the present invention is not limited to the configurations of the accompanying drawings by the entry.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a gear train in a mission case.

FIG. 2 is a vertical sectional side view of the one-way clutch portion in a clutch engaged state.

FIG. 3 is a vertical sectional side view of the one-way clutch portion in a clutch disengaged state.

[Explanation of symbols]

 9 PTO shaft 15 One-way clutch 17 Drive side clutch piece 18 Movable clutch piece 19 Spring 21 Brake mechanism

Claims (1)

[Claims] 1. A power take-out structure for a tractor, wherein a one-way clutch (15) for allowing a preceding rotation of the PTO shaft (9) is interposed in a transmission system to the PTO shaft (9). ), A drive side clutch piece (17) loosely fitted in a fixed position of the PTO shaft (9), and PT
The jump clutch comprises a passive-side movable clutch piece (18) externally fitted and supported on the O-axis (9) so as to be able to transmit torque and shift, and the movable clutch piece (18) is formed on the drive-side clutch piece (17). ) Is equipped with a spring (19) for urging in a direction to be engaged, and a brake mechanism (21) is provided between the PTO shaft (9) and the case (13), and the brake mechanism (21) is
A power take-out structure for a tractor, characterized in that the movable clutch piece (18) displaced backwards against the spring (19) is operated for braking.