JPH09137861A - Auxiliary transmission for tractor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform smooth auxiliary shift operation by a method wherein control of boosting is effected during connection of the shift clutch of the auxiliary transmission. SOLUTION: A main transmission 2 performs speed change of transmission of a reverser 1 and transmits it to an auxiliary gear shifter 3. The auxilary transmission 3 performs further speed change of transmission of a main speed change shifted by the main gear shifter 2 and transmits it to running wheels. In speed change operation of the auxiliary transmission 3, shift clutches 4-7 are provided at each auxiliary speed change and a power is disconnected once, and each time auxiliary speed change is effected, the shift clutches 4-7 are brought into engagement. Besides, during engagement of the shift clutches 4-7, a clutch connection pressure is gradually increased through control of boosting. This constitution absorbs torque during connection of the shift clutches 4-7 and effects smooth connection, reduces the occurrence of a shock during gear shift, and improves operability.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tractor sub-transmission device for smoothly performing a sub-transmission operation.

[0002]

2. Description of the Related Art A tractor transmission device includes a main clutch, a reverser, a main transmission device, an auxiliary transmission device, and the like, and is capable of multi-stage transmission from low speed to high speed for transmission of travel. sell. The sub gear shift is performed using a reverser, a main transmission, and a clutch provided between the main transmission and the sub transmission. However, the reduction gear ratio to reach the auxiliary transmission is large, and the resistance and impact at the time of clutch engagement are large.

[0003]

The present invention relates to a tractor having a reverser 1, a main transmission device 2 and a sub-transmission device 3 for power shifting, and increases the pressure when connecting the shift clutches 4 to 7 in the sub-transmission device 3. The auxiliary transmission is characterized in that it is controlled.

[0004]

The operation and the effect of the invention are transmitted to the traveling device by traveling from the engine side to the auxiliary transmission device 3 via the reverser 1, the main transmission device 2 and the like. In the reverser 1, the transmission direction is switched between forward and reverse, and forward transmission and reverse transmission are performed. The main transmission 2 shifts the transmission from the reverser 1 and transmits it to the sub transmission 3. In this sub transmission 3, each main transmission transmitted by the main transmission 2 is further shifted and transmitted to the traveling wheels.

In such a shift operation of the sub transmission 3,
The shift clutches 4 to 7 are provided for each of the sub shifts to temporarily turn off the power, and the shift clutches 4 to
Enter 7. Moreover, when the shift clutches 4 to 7 are engaged, the clutch connection pressure is gradually increased by the boost control. As a result, the torque when the shift clutches 4 to 7 are engaged is absorbed, resulting in a smooth engagement, which can reduce the impact at the time of gear shift and improve the operability.

[0006]

EXAMPLE A tractor body 8 includes a front engine E body, a clutch housing 9 and a front mission case 1.
The front axle bracket 1 on the front side of the engine E has a rigid structure by connecting the rear transmission case 11 and the like.
A front axle housing is supported below 2, and front and rear wheels 14 that can be steered by steering handles 13 are axially mounted on both left and right ends, and a rear axle housing 15 is connected to both left and right sides of a rear mission case 11. ,
Rear wheels 16 are axially mounted on both left and right ends of the front and rear wheels 1.
When the engine E is driven, the clutch housing 9 and the front and rear mission cases 10, 1
It can travel by transmitting via the transmission mechanism in 1.

A hydraulic case 17 is provided on the rear transmission case 11 and has a lift arm 18 which is vertically rotated by expansion and contraction of a hydraulic cylinder. The working machine connected to the rear part of the vehicle body 8 by a three-point link mechanism is moved up and down. You can control. 50 is a fender and 51 is a cockpit. The transmission mechanism such as the mission cases 10 and 11 has an output shaft 19 of the engine E.
Thus, the clutch shaft 21 can be transmitted by the main clutch 20 in the form of a wet multi-plate. Reference numeral 22 denotes a clutch shifter of the main clutch 20, which can be disengaged by stepping on the clutch petal.

The reverser 1 includes a clutch housing 9
A synchro-type clutch 23 is provided in the front part of the inside, and is provided on a reverser shaft 24. The synchro-type clutch 23 has a synchro-type configuration in which a shifter holding the clutch 23 is manually moved back and forth via a rod. Gears 25 and 26 are provided in front of and behind the reverser shaft 24, and the rotational driving force of the clutch shaft 21 is transmitted to the normal rotation (forward movement) via the counter gear shaft 27-reverser shaft 24 or the counter gear. It is possible to switch between reverse rotation (reverse travel) and conduction via the shaft 27-reverser shaft 28-reverser shaft 24. 29,
Reference numeral 30 denotes a gear on the PTO shaft 31, which can be transmitted by switching the rotation from the counter gear shafts 27 and 28 to the PTO shaft 31 by the speed change clutch 32. This P
The TO shaft 31 extends over the rear end of the rear mission case 11,
The transmission part of the work machine to be connected is transmitted.

The main transmission 2 includes a front mission case 1
0, and the transmission by the reverser shaft 24 is configured to be able to perform four main gear shifts by switching the speed change clutches 33 and 34 of the synchro type. The speed change clutches 33 and 34 are of a power synchro type configuration which is interlocked with a shifter which is operated by hydraulic pressure from a hydraulic operating circuit. Reference numeral 35 denotes a speed change shaft coaxial with the reverser shaft 24, which has the speed change clutches 33, 34 and speed change gears 36, 37, 38, 39 switched by the speed change clutches 33, 34, and a counter gear shaft 40 parallel to the speed change shaft 35. Engage with each gear above.

The sub transmission 3 is disposed between the front mission case 10 and the rear mission case 11, and is a wet multi-plate type shift shift clutch 4, 5, 6, 6.
7 has a power shift configuration in which it is turned on and off by hydraulic pressure from a hydraulic operation circuit to shift gears. The shift clutches 5 and 7 are arranged on a bevel pinion gear shaft 41 that is coaxial with the counter gear shaft 40 that is main-shifted, and an input gear 42 that is integral with the counter gear shaft 40,
It has a transmission gear 43, a transmission gear 44, and the like.

Further, a counter shaft 45 and a counter gear shaft 46 are provided in parallel with the bevel pinion gear shaft 41. On the counter shaft 45, shift clutches 4 and 6 similar to the shift clutches 5 and 7 are provided, and a transmission gear 47 meshing with the input gear 42 and a transmission gear 48 meshing with the transmission gear 43 are integrally formed. A rotary transmission gear 49 and the like are provided. The counter gear shaft 46 has a gear portion that meshes with the input gear 42 and the transmission gear 43.

In such an auxiliary transmission 3, the transmission of the ultra-low speed LL is performed by engaging the shift clutch 4. The transmission at this time is as follows: input gear 42 → counter gear shaft 46 → shift gear 43 → shift gear 48 → shift clutch 4 → counter shaft 45 → transmission gear 49 → transmission gear 44 →
It is performed along the path of the bevel pinion gear shaft 41. Further, the transmission of the low speed L is performed by the engagement of the shift clutch 5. The transmission at this time is performed in the route of the input gear 42, the counter gear shaft 46, the transmission gear 43, the shift clutch 5, and the bevel pinion gear shaft 41. The transmission of the medium speed M is performed by the shift clutch 6 being engaged. The transmission at this time is input gear 42 → transmission gear 47 → shift clutch 6 → counter shaft 45 → transmission gear 49 → transmission gear 44.
→ The process is performed on the path of the bevel pinion gear shaft 41. The transmission of the high speed H is performed by the shift clutch 7 being engaged. The transmission at this time is performed through the path of the input gear 42 → shift clutch 7 → bevel pinion gear 41.

The operating hydraulic circuits of the main transmission 2 and the auxiliary transmission 3 as described above are arranged such that the hydraulic pressure sucked from the tank port T by the hydraulic pump P is passed through the reduce valve 52 to the power steering valve 53 and the auxiliary shift power shift. Circuit 54
To the main transmission power synchro circuit 55, and the respective shift clutches 4 to 7 of the sub transmission 3 and the hydraulic actuators 56 to 59, 60 and 61 of the transmission clutches 33 and 34 of the main transmission 2 as described above. It is configured to operate hydraulically.

Of these, in the auxiliary transmission power shift circuit 54, electromagnetic proportional pressure control valves 62 to 65 are provided to the actuators 56 to 59, respectively, and the electromagnetic proportional pressure control valves 62 to 65 are provided in advance according to a valve drive on-duty A incorporated from a controller having a microcomputer. Output the pressure control valves 62 to 65,
The shift clutches 4 to 7 are gradually turned on and operated by outputting the boost B output of the auxiliary shift actuators 56 to 59. The electromagnetic proportional pressure control valves 62 to 65 of the auxiliary transmission 3 are operated by the output from the controller by manually operating the auxiliary transmission lever.

The shift operation of the main transmission device 2 is performed not only in the manual operation mode but also in the automatic operation mode. In this case, the shift operation of the sub transmission device 3 is performed so as to obtain a travel shift suitable for the work. Thus, the shift of the main transmission 2 is automatically performed by the output of the electromagnetic solenoid valves 66 to 69 from the controller. When the actuators 60, 61 are operated by the switching of the electromagnetic solenoid valves 66-69, the speed change clutches 33, 3
4 enters the speed change gears 36 to 39 from the neutral position, and the speed change transmission is performed.

A rear wheel differential device 70 is transmitted from the bevel pinion gear shaft 41 to the left and right rear wheels 16. Reference numeral 71 denotes a front wheel take-out gear, which is on the front wheel take-out shaft 72 and meshes with the transmission gear 49. This front wheel take-out shaft 7
In the front part of 2, a normal four-wheel clutch 74 and a double speed four-wheel clutch consisting of a wet multi-plate type clutch are provided between a transmission shaft 73 for transmitting to the front wheel differential device of the front axle housing.
When the D clutch 75 is provided and both of these 74, 75 are disengaged, the transmission to the front wheels 14 is not performed, but when the four WD clutch 74 is normally engaged, the front wheels 14 and the rear wheels 16 are almost the same.ゞ It is transmitted at the same speed. Further, when the double speed four WD clutch 75 is turned on during steering turning, the front wheels 14
Is transmitted to the rear wheel 16 at a speed almost twice that of the rear wheel 16 via the speed increasing gear shaft 76.

The electromagnetic solenoid valves 66 to 69 of the main shift power synchronizing circuit 55 are provided on the right side of the mission case 10, and the electromagnetic proportional pressure control valves 62 to 65 of the auxiliary shift power shift circuit 54 are provided on the left side of the mission case 10. Effectively use the space around the vehicle body 8,
The left and right balances are balanced, and the steering brake rod and hydraulic pipes are arranged on the left and right sides, so that the maintenance space can be easily maintained.

In FIG. 5, the difference from the above example is that a single operating lever 77 can be used to selectively shift the work modes M1 to M6, and a shift up button 78 and a shift down button 79 are provided at the grip of the operating lever 77. Is provided, and the vehicle speed is adjusted in each of the work modes M1 to M6 by pressing the button 78 or 79 to easily obtain the optimum vehicle speed.

In the illustrated example, the work modes are a general mode M1, a creep work mode M2, a scraping work mode M3,
Rotary work mode M4, plow, loader work mode M
5 and the traveling mode M6 are set, and a total of 16 are obtained by combining the four-speed shift of the main transmission 2 and the four-speed shift of the auxiliary transmission 3.
With respect to the variable speed travel range of each gear, the reference mode shift positions S1 to S6 for each mode and the mode shift positions S
Depending on the setting of the shift areas V1 to V6 of the areas selected forward and backward by the shift buttons 78 and 79 for each of 1 to S6,
It is possible to efficiently operate the traveling speed suitable for the conditions.

Incidentally, the operation lever 77 for selecting the work modes M1 to M6 in the illustrated example, and the operation of the shift up button 78 and the shift down button 79 may be performed by separate operation tools. 6 and 7, a shifter stay 8 that shift-guides the shifter 81 in the operation interlocking mechanism of the shifter 81 by the sub-shift lever 80 of the sub-transmission device.
2 and a link stay 84 for rotatably supporting a link arm 83 for interlocking the shifter 81 are fixed together with a lock bolt 85 to stabilize and fix to the wall portion of the mission case 10. Is. An arm plate 86 integral with both shifter stays 82 and an arm plate 87 integral with the link stays 84 are attached to the mission case 10.
And the single lock bolt 85 is screwed into these overlapping portions.

These shifter stay 82 and link stay 8
4 is an arm plate 8 with respect to the mission case 10.
It is provided in parallel with supporting the 6, 87 side. The link arm 83 is pivotally supported around a lateral pin 88 at the tip of the link stay 84, and the mission case 1
0 and the lower end of the auxiliary transmission lever 80 and the link arm 83
A link 89 connects the upper part and the upper part. Further, the lower end portion 90 of the link arm 83 can be fitted into an engaging portion 91 projecting in a bifurcated shape on the side surface of the shifter 81, and the shifter 81 can be shift-shifted by the rotation of the shifter arm 83.

[Brief description of the drawings]

FIG. 1 is a shift operation hydraulic circuit diagram and a hydraulic pressure increase graph thereof.

FIG. 2 is a diagram of a transmission mechanism of a tractor.

FIG. 3 is a side view of the tractor.

FIG. 4 is a front sectional view of a mission case portion.

FIG. 5 is a side view of an operation lever showing another embodiment and a graph showing a vehicle speed at each shift.

6A and 6B are a side view and a front view of a sub-shift shifter portion.

FIG. 7 is a perspective view of a part thereof.

[Explanation of symbols]

 1 reverser 2 main transmission 3 auxiliary transmission 4 shift clutch 5 shift clutch 6 shift clutch 7 shift clutch

Claims (1)

[Claims] 1. A tractor having a reverser 1, a main transmission 2, and an auxiliary transmission 3 for power shifting,
A sub-transmission device, wherein pressure increase control is performed when the shift clutches 4 to 7 in the sub-transmission device 3 are engaged.