JPH05180307A - Transmission mechanism for farm tractor - Google Patents

Abstract

PURPOSE:To arrange a junction portion of a front and a rear transmission cases at a safe position in front of the center of gravity and to facilitate an assembly process by fixing a bearing supporting wall on a fixed wall inside the rear transmission case. CONSTITUTION:A bearing supporting wall 4 is made fixable on a fixed wall 110 projecting inside a rear transmission case M2, and a creep shaft 71, an auxiliary transmission shaft 72, a drive pinion shaft 61 and a front wheel driving shaft 63 is made supportable by bearings. A rear end of each shaft born by the bearing supporting wall 4 at its intermediate part is supported by a bearing part provided at a wall part 111 inside the rear transmission case M2. The bearing supporting wall 4 is fixed to the fixed wall 110 inside the rear transmission case M2. By this, a junction part of a front and the rear transmission cases can be arranged at a safe position in front of the center of gravity so as to facilitate an assembly process.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a support arrangement for a forward / reverse speed change mechanism, a creep speed change mechanism, an auxiliary speed change mechanism, and a front wheel speed increasing mechanism in a tractor mission mechanism.

[0002]

2. Description of the Related Art In a conventional transmission mechanism of an agricultural tractor, a forward transmission mechanism, a creep transmission mechanism, an auxiliary transmission mechanism, and a front wheel speed increasing mechanism, which are arranged at the rear portion of a mission case, include a front mission case and a rear portion. It was supported by a partition wall between the mission cases, and the partition wall was sandwiched and fixed between the front mission case and the rear mission case. However, in the case of such a configuration, the partition wall is sandwiched in the most stressed portion near the center of gravity of the tractor, and since this portion is the bearing portion, the deflection is large and the oil leakage becomes severe. It was happening. Further, conventionally, a reverse rotation idle gear shaft and a creep shaft of the forward / reverse speed change mechanism are separately provided at a joint portion of the forward / reverse speed change mechanism and the creep speed change mechanism.

[0003]

SUMMARY OF THE INVENTION The present invention solves the problems of the prior art, that is, the partition wall portion is not provided at the connecting portion of the front mission case and the rear mission case, but the rear portion thereof is not provided. The above problem was solved by configuring the bearing support wall to be attached to the inner wall of the mission case. In addition, the reverse rotation idle gear shaft of the forward / reverse transmission mechanism is also configured as a mechanism that doubles as a creep shaft as it is, the number of shafts and gears is reduced, and the mission case is made compact. Also, the PTO is provided with a reversing mechanism so that the reversing work can be easily performed.

[0004]

The problems to be solved by the present invention are as described above. Next, the means for solving the problems will be described. That is, the forward / reverse speed change mechanism, the creep speed change mechanism, the auxiliary speed change mechanism, and the front wheel speed-increasing mechanism are arranged in the transmission case in the vicinity of the detachable bearing support wall 4, and the gear change mechanism is provided on the bearing support wall 4. It is possible to fix the shafts constituting the above to the fixed wall 110 of the mission case in the assembled state.

Further, in the structure in which the creep speed change mechanism is arranged in the rear stage of the forward / reverse speed change mechanism, the reverse gear 36 and the reverse speed gear shaft for obtaining the reverse rotation of the forward / reverse speed change mechanism are replaced by the speed change gear and the creep shaft of the creep speed change mechanism. It was also used as 71.

Further, power is transmitted from the PTO drive shaft to the reverse rotation driven gear via the PTO reverse rotation gear, and the reverse rotation driven gear is moved to P
The power is transmitted to the PTO shaft when the TO reverse slider is turned on and off.

[0007]

[Operation] Next, the operation will be described. That is, the part of the bearing support wall, which has been conventionally arranged near the center of gravity of the tractor, is sandwiched between the front mission case and the rear mission case, and the maximum stress is applied to this part, so that it easily bends. This portion was the cause of oil leakage, but in the present invention, the bearing support wall 4 is fixed to the fixed wall 110 inside the mission case M2 at the rear portion, so that the front portion is fixed. The joint between the mission case M1 and the rear mission case M2 could be arranged at a safe position in front of the center of gravity. In addition, the creep shaft 71 could be used as it is without providing a separate reverse rotation gear shaft for the forward and backward transmission mechanism.

[0008]

EXAMPLES Next, examples will be described. FIG. 1 is a skeleton diagram showing the overall configuration of the mission mechanism of the agricultural tractor of the present invention. Referring to FIG. 1, a hydraulic clutch type main transmission mechanism will be described. Power is transmitted from the engine E to the input shaft 65 via the main clutch, the input gear 11 at the rear end of the input shaft 65 is inserted into the transmission case, and loosely fitted on the main transmission hydraulic clutch shaft 66. It meshes with the first speed gear 12. The first speed gear 12 includes a main transmission shaft and a PTO drive shaft 67.
It meshes with the first-speed driven gear 16 above. Similarly, the second speed gear 13 on the main speed change hydraulic clutch shaft 66 is the second speed drive gear 17 on the main speed change shaft / PTO drive shaft 67, the third speed gear 14 is the third speed drive gear 18, and the fourth speed gear. The gear 15 meshes with the fourth speed drive gear 19. The first speed gear 12 drives the main speed changing hydraulic clutch shaft 66 by connecting the first speed hydraulic clutch 26, and the second speed gear 13 drives the main speed changing hydraulic clutch shaft 66 by connecting the second speed hydraulic clutch 27. 14 drives the main shift hydraulic clutch shaft 66 by joining the 3rd speed hydraulic clutch 28, and the 4th speed gear 15 drives the 4th speed hydraulic clutch 29.
The main shift hydraulic clutch shaft 66 is driven by joining the above. 6
Is a bearing oil passage plate 6 attached to the front part of the center plate 7, and supports the main shift hydraulic clutch shaft 66, the main shift shaft / PTO drive shaft 67, and the PTO reverse rotation gear shaft 74 as bearings.

Next, a hydraulic clutch type forward and backward transmission mechanism will be described. The reverse gear 32 is loosely fitted to the rear end of the main shift hydraulic clutch shaft 66, and the reverse gear 32 is rotated by the engagement of the reverse hydraulic clutch 30 to rotate the reverse counter shaft 7
It is meshed with the gear 33 on the upper part 3. The reverse counter shaft 7
The gear 34 at the end of No. 3 meshes with the gear 36 of the creep shaft 71. The reverse rotation is transmitted by the gear train. In the case of forward movement, the rotation of the main shift hydraulic clutch shaft 66 is transmitted to the gear 35 by the engagement of the forward hydraulic clutch 31, and the gear 35 is directly meshed with the gear 36 on the creep shaft 71. Therefore, the forward rotation is transmitted.

Next, the creep transmission mechanism will be described. The speed change slider 10 is supported on the creep counter shaft 70 on which the gear 35 is fixed, and the speed change slider 10 slides forward to integrate the creep counter shaft 70 and the auxiliary speed change shaft 72. The creep high speed is transmitted to the sub speed change shaft 72, and the speed change slider 10 is integrated with the gear 38 side, so that the creep low speed is changed from the gear 35 to the gear 36, the creep shaft 71, and the gear 37. 72.

Next, the auxiliary transmission mechanism will be described. The creep low speed from the creep shaft 71 is transmitted to the gear 38 on the sub speed change shaft 72, and the creep high speed is transmitted by the creep slider shaft 70 and the sub speed change shaft 72 being integrated by the speed change slider 10. Other transmission gears 39 and 40 are loosely fitted on the auxiliary transmission shaft 72, and are constantly meshed with the driven gears 41 and 42 on the drive pinion shaft 61.
Then, by operating the shift slider 59, a high / low shift of the sub shift can be obtained. The rotation after the sub-shift is from the pinion 50,
It is transmitted to the ring gear 55 of the differential gear device 56. The gear 57 on the differential side shaft meshes with the gear 58 on the axle to drive the rear wheel 51.

Next, the PTO shift will be described. On the main transmission shaft and PTO drive shaft 67, the 1st speed driven gear 16 and 2
The high-speed drive gear 17, the third-speed drive gear 18, and the fourth-speed drive gear 19 are connected to the PTO fourth-speed gear 20 on the PTO transmission shaft 68.
, PTO third speed gear 21, PTO second speed gear 22, P
It meshes with the TO first speed gear 23. Then, the forward and backward movements of the PTO speed change slider 103 provide the PTO fourth speed and the third speed. Further, the forward and backward movements of the PTO speed change slider 102 provide the PTO second speed and the first speed. 4th speed drive gear 1
9 meshes with the PTO reverse rotation gear 25 on the PTO reverse rotation gear shaft 74, and the PTO reverse rotation gear 25 meshes with the reverse rotation driven gear 24 on the PTO speed change shaft 68, and the PTO reverse rotation slider 1
By sliding 01, the PTO transmission shaft 68 is rotated in the reverse direction.
The PTO speed change shaft 68 is coupled to the PTO shaft 62 by the coupling.
To the rear of the mission case. The PTO shaft 62 drives the tiller claw shaft 53 from the bevel gear box shaft 54 of the rotary tiller.

Next, the front wheel drive transmission mechanism will be described.
The driven gear 41 on the drive pinion shaft 61 is always meshed with the front wheel drive gear 43 on the front wheel drive shaft 63, and the front wheel power is taken out only when the drive pinion shaft 61 rotates. The front wheel high speed drive gear 44 and the front wheel standard drive gear 45 are fixedly mounted on the front wheel drive shaft 63. The front wheel high speed drive gear 44 meshes with the front wheel high speed driven gear 46 on the front wheel speed change counter shaft 64, and the front wheel standard drive gear 45 meshes with the front wheel standard driven gear 49 on the front wheel speed change counter shaft 64. A mechanical clutch portion 48 that joins the front wheel standard driven gear 49 to the front wheel shift counter shaft 64 and a hydraulic clutch portion 47 that joins the front wheel high speed driven gear 46 to the front wheel shift counter shaft 64 are configured. The mechanical clutch unit 48 constitutes a hydraulic actuator and serves both to join the hydraulic clutch unit 47. That is, when the mechanical clutch 48 is pressed by the pressure oil, the hydraulic clutch 47 is pressed.
When the pressure oil is discharged to the drain circuit and returned by the biasing spring, the mechanical clutch portion 48 and the front wheel standard driven gear 49 mesh with each other. The front wheel shift counter shaft 64 moves the front wheel intermediate shaft 6 by the forward and backward movement of the front wheel clutch 60.
Power is transmitted from 9 to the front wheels 52.

FIG. 2 is an enlarged side sectional view of the main transmission mechanism portion of the mission mechanism of the agricultural tractor. FIG. 3 is an enlarged side sectional view of the main transmission shaft / PTO drive shaft 67 and PTO transmission shaft 68 portions. 5 is an enlarged side sectional view of the forward / reverse speed change mechanism, FIG. 5 is an enlarged side sectional view of the creep speed change mechanism and the auxiliary speed change mechanism, and FIG. 6 is a front view of the fixed wall 110 provided with the bearing support wall 4.

In FIG. 2, the mission cases are a front mission case M1 and a rear mission case M2.
The center plate 7 is sandwiched and fixed between the two. The bearing oil passage plate 6 is arranged in the front part of the center plate 7, and the bearing support hole 6a of the bearing oil passage plate 6 is arranged.
The main shift hydraulic clutch shaft 66, the main shift shaft / PTO drive shaft 67, and the PTO reverse rotation gear shaft 74 are bearing-supported at 6b and 6c. The variable speed hydraulic clutch shaft 66 supports the hydraulic clutches 26, 27, 28 and 29 of the main speed change mechanism on the front side of the bearing oil passage plate 6, and the hydraulic oil for the forward and reverse speed change mechanism is provided at the rear portion of the bearing oil path plate 6. It supports the clutches 30 and 31. A relief valve 5 is arranged above the bearing oil passage plate 6 to eject return oil.

In FIG. 3, the fourth speed drive gear 19 on the main transmission shaft / PTO drive shaft 67 is replaced by the PTO reverse rotation gear shaft 74.
Mesh with PTO reverse gear 25 above
The configuration in which 5 meshes with the reverse rotation driven gear 24 on the PTO transmission shaft 68 is disclosed, and the configuration in which the PTO reverse rotation is obtained is disclosed.

4 and 5, parts of the forward / reverse speed change mechanism, the creep speed change mechanism, the auxiliary speed change mechanism, and the front wheel speed increasing mechanism of the present invention are shown. The portion where the end of the shift hydraulic clutch shaft 66 projects from the center plate 7 has a cantilever shape, and the forward hydraulic clutch 31 is engaged with the friction plate of the reverse gear 35 protruding from the creep counter shaft 70. Therefore, when the forward hydraulic clutch 31 is engaged, the rotation of the shift hydraulic clutch shaft 66 is directly transmitted to the creep counter shaft 70. Conversely, when the reverse hydraulic clutch 30 is engaged, the rotation of the shift hydraulic clutch shaft 66 is transmitted from the reverse gear 32 to the gear 34 via the gear 33 and the reverse counter shaft 73, and the gear 34 is rotated by the reverse gear 3.
6 and the reverse gear 36 meshes with the reverse gear 35, the reverse speed is transmitted to the creep counter shaft 70. In the present invention, the reverse gear shaft in which the reverse rotation gear 36 is arranged is used as the creep shaft 71 to form a creep transmission mechanism.

In the creep transmission mechanism, the rotation of the reverse rotation gear 36 is changed from the creep shaft 71 through the gear 37 to the auxiliary transmission shaft 72.
When the power is transmitted to the gear 38 above, the creep speed becomes low. The high creep speed is transmitted by the rotation of the creep counter shaft 70 being transmitted to the auxiliary transmission shaft 72. Further, a high and low auxiliary transmission device is formed between the auxiliary transmission shaft 72 and the drive pinion shaft 61, and a front wheel speed increasing mechanism is formed between the front wheel drive shaft 63 and the front wheel transmission counter shaft 64. .

In the above-mentioned structure, as shown in FIG. 5, the bearing support wall 4 can be fixed to the fixed wall 110 protruding inside the rear mission case M2, and the creep shaft 71 and the creep shaft 71 are fixed to the bearing support wall 4. The sub-transmission shaft 72, the drive pinion shaft 61, and the front wheel drive shaft 63 can be supported by bearings. The rear end of each shaft bearing the middle portion of the bearing support wall 4 is supported by the bearing portion provided on the wall portion 111 inside the rear mission case M2. The state in which the bearing support wall 4 is fixed to the fixed wall 110 inside the rear mission case M2 is shown in FIG.

[0020]

Since the present invention is configured as described above, it has the following effects. That is, since it is configured as in claim 1, the portion of the bearing support wall, which is conventionally arranged near the center of gravity of the tractor, is sandwiched between the front mission case and the rear mission case. Since the maximum stress is applied to, it is easy to bend, and this part was the cause of oil leakage, but in the present invention,
Since the bearing support wall 4 is configured to be fixed to the fixed wall 110 inside the rear mission case M2, the joint portion between the front mission case M1 and the rear mission case M2 is safer in front of the center of gravity. It was possible to place it in the position. Further, the forward / backward speed change mechanism, the creep speed change mechanism, the auxiliary speed change mechanism, and the front wheel speed increasing mechanism can be assembled in the rear mission case M2 as a semi-mechanical assembly on the bearing support wall 4, so that the assembly process can be performed. It has become easier.

According to the second aspect of the present invention, the creep shaft 71 can be used as it is without separately providing a reverse rotation gear shaft for the forward / reverse speed change mechanism. Further, the capacity and length of the mission case could be made compact as compared with the case where the reverse gear 36 and the reverse gear shaft are separately arranged. In addition, since the support shaft of the reverse gear 36 is also used as the full-scale creep shaft 71, the support mechanism of the forward / reverse speed change mechanism can be strengthened.

According to the third aspect of the invention, since the PTO reverse rotation slider 101 is provided, the reverse rotation work of the working machine is possible, and the reverse rotation mechanism can be made compact. Further, conventionally, it was necessary to provide a reversing mechanism on the side of the working machine, and the operator could not perform the reversing operation while sitting in the driver's seat, but with the configuration according to the present invention, it is possible to keep sitting in the driver's seat. It is possible to reverse the working machine. Further, since the reverse rotation can be decelerated by the reverse rotation driven gear 24, it is possible to set it in the low speed range of the forward rotation, and the reverse operation can be performed in a safe rotation range.

[Brief description of drawings]

FIG. 1 is a skeleton diagram illustrating an overall configuration of a mission mechanism of an agricultural tractor according to the present invention.

FIG. 2 is an enlarged side sectional view of a main transmission mechanism portion of the mission mechanism of the agricultural tractor.

FIG. 3 is a main transmission shaft and PTO drive shaft 67 and a PTO transmission shaft 6
8 is an enlarged side sectional view of a portion 8;

FIG. 4 is an enlarged side sectional view of a forward / reverse speed change mechanism.

FIG. 5 is an enlarged side cross-sectional view of a creep transmission mechanism and a sub transmission mechanism.

FIG. 6 is a front view of a portion of a fixed wall 110 provided with a bearing support wall 4.

[Explanation of symbols]

 M1 front mission case M2 rear mission case 4 bearing support wall 24 reverse rotation driven gear 25 PTO reverse rotation gear 30 reverse hydraulic clutch 31 forward hydraulic clutch 36 reverse rotation gear 36 67 PTO drive shaft (main transmission shaft) 71 creep shaft 101 PTO reverse rotation Slider 110 Fixed wall

Claims (3)

[Claims] 1. A forward / reverse speed change mechanism, a creep speed change mechanism, an auxiliary speed change mechanism, and a front wheel speed increasing mechanism are arranged in the transmission case in the vicinity of a detachable bearing support wall 4, and these bearing support wall 4 are provided with these components. The fixed wall 11 of the mission case is assembled with the shafts constituting the transmission mechanism of FIG.
A mission mechanism for agricultural tractors, which can be fixed to 0. 2. In a structure in which a creep speed change mechanism is arranged at a rear stage of the forward / reverse speed change mechanism, a reverse gear 36 and a reverse speed gear shaft for obtaining reverse rotation of the forward / reverse speed change mechanism are provided as a shift gear and a creep shaft of the creep speed change mechanism. The mission mechanism of an agricultural tractor, which is also used as 71. 3. Power is transmitted from a PTO drive shaft to a reverse driven gear via a PTO reverse gear, and the reverse driven gear is connected to the PTO.
A transmission mechanism for an agricultural tractor characterized in that power is transmitted to a PTO shaft by turning a reverse slider on and off.