JP3161903B2 - Tractor power take-out structure - Google Patents

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 having a one-way clutch for allowing the PTO shaft to rotate forward in a transmission system to a PTO shaft for driving an attachment such as a mower.

[0002]

2. Description of the Related Art The above-mentioned one-way clutch is used to avoid the occurrence of a body moving force due to the driving system being driven by the inertial rotational force of an attachment when the main clutch is disengaged and the body is stopped. A jump clutch type and other types are appropriately selected and used [Japanese Patent Laid-Open No. 2-28022].

[0003]

By providing the one-way clutch, the transmission of the inertial rotational force of the attachment to the traveling system is avoided, but the inertial rotation of the attachment itself is continued. there were. The present invention has been made in view of such a situation,
It is an object of the present invention to prevent unintended movement of an airframe due to an inertial rotation force of an attachment, and to quickly prevent inertial rotation of the attachment itself.

[0004]

According to a first aspect of the present invention, there is provided a power transmission system for a PTO shaft, wherein a one-way clutch which allows a preceding rotation of the PTO shaft is interposed. In a power take-out structure for a tractor, the one-way clutch is loosely fitted on the PTO shaft at a fixed position on a drive side clutch piece, and a passive movable clutch piece externally supported on the PTO shaft so as to be capable of transmitting torque and shifting. A jump clutch comprising: a PTO shaft equipped with a coil spring that biases the movable clutch piece in a direction to engage the driving clutch piece, and a brake mechanism between the PTO shaft and the case, This brake mechanism is configured to perform a braking operation by the movable clutch piece displaced backward against the coil spring.

According to a second aspect of the present invention, in the first aspect of the present invention, the power transmission to the PTO shaft is switched on and off on the upper transmission side of the one-way clutch. It is in the point that it is.

According to a third aspect of the present invention, in the first and second aspects of the present invention, a case is attached to the lower abdomen of the transmission case, and the one-way clutch is attached to the case. In that the brake mechanism is installed.

[0007]

According to the above arrangement, when the main clutch is disengaged, the one-way clutch of the jump clutch structure operates to cut off 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 of shifting the movable clutch piece in the one-way clutch away from the drive-side clutch piece, and the PTO shaft is braked.

[0008]

Thus, according to the present invention, the one-way clutch can prevent the aircraft from being unduly moved by the inertial rotational force of the attachment when the main clutch is disengaged, and the operation of the one-way clutch can be effectively used. As a result, the inertial rotation of the attachment itself can be quickly stopped, and safety can be improved.

[0009]

FIG. 1 shows a gear train having a transmission structure which is 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.
, And then transmitted to the final transmission shaft 5 via the auxiliary gear transmission mechanism 4 and the bevel pinion gear P
G is transmitted to the rear wheel differential mechanism 6 via G. Further, the output branch gear G6 provided on the final transmission shaft 5 is shifted to the shift gear SG.
6 is transmitted to a front-wheel differential mechanism (not shown) via a front-wheel transmission shaft 7 so that propulsion by four-wheel drive is performed.

The main gear transmission mechanism 2 includes transmission gears G1, G2, G3 fixed to the input shaft 1, and three shift gears SG1, SG2, SG spline-fitted to the intermediate shaft 3.
The first forward speed is established by shifting the shift gear SG1 rightward and engaging the transmission gear G1, and the second forward speed is established by shifting the shift gear SG2 leftward and engaging the transmission gear G2. By shifting the shift gear SG3 rightward and engaging the transmission gear G3, the third forward speed is shifted, and the shift gear SG1 is further shifted leftward to engage the idle gear IG1 loosely fitted to the front wheel transmission shaft 7. As a result, the first reverse speed is obtained. The idle gear IG2 integrated with the idle gear IG1 is always engaged with the gear G2.

The sub-gear transmission mechanism 4 comprises transmission gears G4, G5 fixed to the intermediate shaft 3, and a pair of shift gears SG4, SG5 spline-fitted to the final transmission shaft 5, with the shift gear SG4 moving rightward. Shift and change gear G
4 and the shift gear SG5
Is shifted to the left and engaged with the transmission gear G5 to obtain a high speed. By combining the shifts of the main gear transmission mechanism 2 and the sub gear transmission mechanism 4, a multi-stage transmission of six forward steps and two reverse steps can be performed. The front wheels that receive the branch power from the final transmission shaft 5 are also configured to be shifted in synchronization with the rear wheels. When the shift gear SG6 is shifted rightward 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 transmission case M of the tractor is provided with a rear PTO shaft 8 for driving an attachment such as a rotary tilling device and an intermediate PTO shaft 9 for driving a mid-mount type mower.

The rear PTO shaft 8 projects rearward from the rear of the transmission case M, and the power branched from the input shaft 1 is supplied to the first PTO transmission shaft 10, the second PTO transmission shaft 11, and the reduction gear G7. , G8 via rear PTO
It is transmitted to the shaft 8 and driven at a constant speed irrespective of 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 transmission gear G2.
The TO transmission shaft 10 and the second PTO transmission shaft 11 are coaxially linked via a one-way clutch 12 of a jump clutch type, and the rotation of the second PTO transmission shaft 11 is reduced by the reduction gears G7 and 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 by the transmission gear G3 and the first PTO transmission. A first intermediate gear G9 loosely fitted on the shaft 10, a second intermediate gear G loosely fitted on the fixed intermediate shaft 16;
10, transmitted to the intermediate PTO shaft 9 via the passive gear G11, the gear clutch 14, and the one-way clutch 15 loosely fitted to the intermediate PTO shaft 9, so as to be driven at a constant speed regardless of the traveling system. Has become.

The one-way clutch 15 comprises a driving clutch piece 17 loosely fitted to the intermediate PTO shaft 9 and a passive movable clutch piece 18 splineably fitted to the intermediate PTO shaft 9 so as to be shiftable. Each is engaged with each other via the engaging portions 17a and 18a formed at the opposing portions, and the movable clutch piece 18 is urged in the engaging direction by a weak spring 19 externally fitted to the intermediate PTO shaft 9, and
The engaging portions 17a and 18a are arranged such that when the movable clutch piece 18 rotates ahead of the drive side clutch piece 17, the movable clutch piece 18 is displaced backward against the spring 19 in a direction away from the drive side clutch piece 17. It has a structure with an inclined cam surface, a so-called jump clutch structure.

The gear clutch 14 transmits power to the one-way clutch 15 by spline-fitting the shift sleeve 20 over the boss of the drive-side clutch piece 17 and the boss of the passive gear G11. The transmission of power to the one-way clutch 15 is released by shifting the sleeve 20 rightward in the figure and disengaging it from the boss of the passive gear G11.

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

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

In the embodiment, the case where the brake mechanism 21 acts only on the intermediate PTO shaft 9 has been exemplified.
A similar brake mechanism 21 may be applied to the shaft 8.

In the claims, reference numerals are provided for convenience of comparison with the drawings, but the present invention is not limited to the configuration shown in the attached drawings.

[Brief description of the drawings]

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

FIG. 2 is a longitudinal sectional side view of a one-way clutch unit in a clutch engaged state.

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

[Explanation of symbols]

 9 PTO shaft 13 Case 14 Gear clutch 15 One-way clutch 17 Drive side clutch piece 18 Movable clutch piece 19 Spring 21 Brake mechanism M Transmission case

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-2-225135 (JP, A) JP-A-5-164162 (JP, A) JP-A 1-150128 (JP, U) JP-A 55- 3082 (JP, U) Hira 1-102532 (JP, U) (58) Field surveyed (Int. Cl. ⁷ , DB name) B60K 17/28-17/36 F16D 67/02

Claims (3)

(57) [Claims] 1. A power take-out structure for a tractor in which a one-way clutch (15) for allowing advance rotation of a PTO shaft (9) is interposed in a transmission system to a PTO shaft (9), wherein the one-way clutch (15) ), A drive-side clutch piece (17) loosely fitted at a fixed position of the PTO shaft (9),
A jump clutch comprising a passive-side movable clutch piece (18) externally supported so as to be able to transmit torque and shift to the O-axis (9), and this movable clutch piece (18) is used as a drive-side clutch piece (17). ) Is provided, and a brake mechanism (21) is provided between the PTO shaft (9) and the case (13). The brake mechanism (21)
A power take-out structure for a tractor, wherein a braking operation is performed by the movable clutch piece (18) displaced backward against the spring (19). (2) On the transmission side of the one-way clutch (15)
The power transmission to the PTO shaft (9) is turned on and off.
The power take-out structure for a tractor according to claim 1, wherein the power take-out structure is provided. (3) Case (13) is a mission case
(M) attached to the lower abdomen.
With a clutch (15) and a brake mechanism (21)
A tractor power take-out structure according to claim 1 or 2.
Build.