JPH078612B2 - Tractor power transmission device - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power transmission device for a tractor for agriculture or the like.

2. Description of the Related Art Conventionally, in an agricultural tractor, an engine is mounted on the entire vehicle body and a mission case is mounted on the rear part. A seat is arranged above the mission case. The output of the engine is transmitted to the input shaft of the mission case via the propeller shaft. The transmission in the mission case is often divided into a main transmission and an auxiliary transmission, and such a tractor transmission is disclosed in Japanese Utility Model Publication No. 47-27295.

In this mission device, a main transmission device and an auxiliary transmission device are arranged in front and rear, a differential device is arranged between these main and auxiliary transmission devices, and the engine power transmitted through the input shaft is transmitted to the main transmission device. After being accelerated and decelerated by the device and the auxiliary transmission, it is transmitted to the rear wheels via a differential device connected to the auxiliary transmission. The mission device also includes a front-wheel drive shaft that transmits the changed engine power to the front wheels, and a power take-off shaft or PTO shaft that transmits the changed engine power to the work machine.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention In the above-described conventional device, the angular axes are arranged in three stages of upper, middle, and lower, and both ends of an upper shaft and a lower shaft longitudinally passing through the inside of the mission case. Each of them is provided with a speed change gear. Therefore, the height of the mission case is increased from the front part to the rear part as a whole, and the height of the seat disposed above the mission case is inevitably increased accordingly. In addition, in this device, the PTO shaft is located at the bottom of the mission case, but since the PTO shaft must be placed at a predetermined height position in relation to the work machine, the height of this PTO shaft is The position of the mission case becomes higher and the seat height becomes higher.

Therefore, the present invention is intended to provide a mission device in which the height of the upper part of the mission case is made as low as possible to reduce the seat height and the ground height of the lower part of the mission case is sufficiently high.

Therefore, according to the present invention, in the present invention, the main transmission and the auxiliary transmission for vehicle speed shifting are arranged side by side in the transmission case, which is disposed below the seat. Further, in a power transmission device of a tractor in which a differential device is arranged between the main transmission device and the sub transmission device, a first main transmission shaft and a second main transmission shaft that extend in the front-rear direction and are parallel to each other are arranged in the main transmission device. Installed, the first main transmission shaft is extended to the sub transmission, the front wheel drive shaft is extended from the sub transmission to the front end of the mission case, and both of these shafts are connected to the main transmission and the sub transmission. A PTO shaft that is arranged below the differential shaft that extends in the direction perpendicular to the shaft with the device and that extends from the front part to the rear end of the mission case above the differential shaft. And a transmission gear for transmitting rotation to the PTO shaft is provided on the main transmission side.

According to the present invention, since the PTO shaft is arranged in the upper part of the mission case, the mission case mounted on the vehicle body with the PTO shaft at a predetermined height occupies a relatively low position. The top of the mission case is usually
A hydraulic cylinder device for operating a lift arm for raising and lowering the work machine is mounted, and a seat is provided above the hydraulic cylinder device. However, since the upper surface of the mission case is at a low position as described above, the seat position is also low.

Further, in the present invention, the transmission gear for transmitting the rotation to the PTO shaft is provided on the main transmission side, that is, in the front part of the transmission case, and there are no gears extending around the rear part of the PTO shaft. Since the shafts other than the PTO shaft are arranged in the lower part of the mission case, the upper surface of the rear part of the mission case can be formed closer to the PTO shaft and lower than the front part. Therefore, by mounting the hydraulic cylinder device on the lower upper surface of the rear portion, the seat can be provided at a lower position.

Further, by arranging the first main transmission shaft, the second main transmission shaft, and the front wheel drive shaft disposed in the lower portion side by side in the left-right direction at substantially the same height, the respective shafts constituting the transmission are transmitted to the transmission case. Since the shafts are arranged in upper and lower two stages, the height of the mission case itself is lower than that of the conventional device in which the shafts are arranged in upper, middle and lower stages, and therefore the PTO shaft is Despite the fact that it is arranged on the upper part, the ground height of the lower surface of the mission case can be made sufficiently high.

Examples Hereinafter, the present invention will be described with reference to illustrated examples. FIG. 1 is an overall side view of an agricultural tractor to which the present invention is applied.
Is a rear wheel and 2 is a front wheel. The engine 3 is mounted on the front part of the vehicle body, and the mission case 4 is mounted on the rear part. An output shaft of the engine 3 is connected to a propeller shaft 6 via a reduction gear 5, and the propeller shaft 6 extends rearward at a lower portion of the vehicle body and is connected to an input shaft 7 of a mission case 4.

A main transmission 8 and an auxiliary transmission 9 are arranged in the front and rear in the mission case 4, and the engine power transmitted via the input shaft 7 is accelerated and decelerated by the main transmission 8 and the auxiliary transmission 9. , Is transmitted to the differential shaft 10 via a differential device arranged between the main transmission device 8 and the auxiliary transmission device 9, and is further transmitted to the rear axle 11 via a final reduction gear device. The power that has passed through the main and auxiliary transmissions is also transmitted to the front wheels 2 via the front wheel drive propeller shaft 12. Further, the engine power input to the input shaft 7 is transmitted to the PTO shaft 13 after being changed by the main transmission 8.

The PTO shaft 13 transmits power to a working machine such as a rotary working machine connected to the rear part of the tractor. The working machine is pivotally supported by a hydraulic cylinder 14 provided at an upper portion of the mission case 4, and a lift arm 15 that swings up and down in conjunction with a piston of the hydraulic cylinder, and a swing arm that pivots on a side surface of the mission case 4. It is connected to the tractor via the supported lower arm 16 and moves up and down according to the operation of the hydraulic cylinder 14. A seat 50 is provided above the mission case 4.

FIG. 2 is a plan sectional view showing the power transmission mechanism in the mission case 4. FIG. 3 is a drawing showing the positional relationship of each axis in the mission case 4, and is an end view of the inside of the mission case 4 as seen from the rear. As can be seen from these drawings, a first main transmission shaft S1 is provided in the transmission case 4 on the left side thereof in a longitudinal manner from a front end portion to a rear end portion, and a second main transmission shaft S1 is provided in a front portion of a central portion. A shaft S2 and a sub-transmission shaft S3 are arranged at the rear part thereof. Then, the PTO shaft 13 extends above the second main transmission shaft S2 and the sub transmission shaft S3 from the front portion to the rear portion, and the PTO shaft 13
The rear part extends rearward from the mission case 4.
A rear wheel drive shaft S4 is arranged at a position at a rear intermediate height in a rightward position in the mission case 4, and a front wheel drive shaft S5 is arranged below the rear wheel drive shaft S4. The front wheel drive shaft S5 extends to the front end of the mission case 4 and is connected to the front wheel drive propeller shaft 12 (FIG. 1). Differential axis
10 is above the first main transmission shaft S1 and the front wheel drive shaft S5, and the PTO shaft 1
It is arranged underneath 3 perpendicularly across these axes. SP is a pump shaft that drives a hydraulic pump for latch hydraulic oil and lubricating oil. All of these axes are arranged parallel to each other in the front-rear direction.

Reference numeral 17 is a main clutch, and engine power is transmitted from the input shaft 7 to the main clutch 17, and is input into the mission case 4 via the main clutch shaft 18. The main clutch shaft 18 is rotatably supported by the transmission case 4 via a ball bearing, and the front end of the first main transmission shaft S1 is the main clutch shaft 18.
It is rotatably supported at the rear end portion thereof by a needle bearing. The rear end of the main clutch shaft 18 also has a gear G ₁₃
Are integrally provided, and the gear G ₁₃ is connected to the second main transmission shaft S 2
It always meshes with the gear G ₂₃ fixed to. Therefore the second
The main transmission shaft S2 is always driven and rotated by the engine when the main clutch 17 is engaged. A main transmission device 8 that shifts and transmits this rotation of the second main transmission shaft S2 to the first main transmission shaft S1 is provided between both main transmission shafts. The main transmission 8 includes a first speed hydraulic speed change clutch 19 and a fourth speed / reverse hydraulic speed change clutch 20 fixed to the second main speed change shaft S2, and a second speed hydraulic speed change clutch 21 and 3 fixed to the first main speed change shaft S1. A first speed hydraulic speed change clutch 19 and a high speed hydraulic speed change clutch 22.
, The rotation of the second main transmission shaft S2 is transmitted to the first main transmission shaft S1 via the gears G ₂₁ and G ₁₁ , and when the fourth speed / reverse hydraulic transmission clutch 20 is engaged, the selector 23 slides. The second main transmission shaft via gears G ₂₄ , G ₁₄ or gears G _2R , G _1R depending on the moving position
The rotation of S2 is transmitted to the first main transmission shaft S1. An idle gear (not shown) is interposed between the gear G _2R and the gear G _1R ,
When power is transmitted through these gears, the first main transmission shaft S1 rotates in the reverse direction. 2nd hydraulic clutch 21
Is engaged, the rotation of the second main transmission shaft S2 is transmitted to the first main transmission shaft S1 via the gears G ₂₂ and G ₁₂ . When the third speed hydraulic speed change clutch 22 is engaged, the gear G ₁₃ is connected to the first main speed change shaft S1, and the first main speed change shaft S1 is directly driven by the main clutch shaft 18 without passing through the second main speed change shaft S2. To be done.

In this way, the main transmission 8 has four forward gears and one reverse gear.
The gear is selectively changed in five stages, and the changed rotational force is transmitted to the rear sub-transmission device 9 through the first main transmission shaft S1. The sub transmission 9 is provided between the rear portion of the first main transmission shaft S1 and the sub transmission shaft S3, and includes a gear G ₆₁ , a gear G _62, and a gear G ₆₃ fixed to the first main transmission shaft S1. , A gear G ₃₁ which is loosely fitted to the sub-transmission shaft S3 via a needle bearing and meshes with the gear G _61, and a gear G ₃₃ which is also loosely fitted to the sub-transmission shaft S3 and meshes with the gear G ₆₃ and a sub-gear slidably spline-fitted around the shaft S3, it is possible to disengage the gear G _62,
At the front end position and the rear end position, it is constituted by the gear G ₃₁ or the gear G ₃₃ and the gear G ₃₂ that connects the auxiliary gear shaft S3. Therefore, depending on the sliding position of the gear G ₃₂ , the first
Rotation is transmitted from the main gear shift shaft S1 to the sub gear shift shaft S3 with a gear ratio of three, and the main gear shift device 8 and the sub gear shift device 9 move forward.
It is possible to switch between 12 speeds and 3 reverse speeds.

A gear G ₃₄ is further fixed to the sub-transmission shaft S3,
The gear G ₃₄ meshes with the gear G ₅₄ . The gear G ₅₄ is loosely fitted to the front wheel drive shaft S5 via a needle bearing, but can be freely contacted with and separated from the front wheel drive shaft S5 by the selector 24, so that the front wheel can be driven through the front wheel drive shaft S5 as necessary. There is. The gear G ₅₄ and the gear G ₅₁ is fixed integrally, the gear G ₅₁ is, have I fixed to gear G ₄₁ and meshed with the rear wheel drive shaft S4.

A differential device 25 is arranged between the main transmission device 8 and the auxiliary transmission device 9, and a small bevel gear 26 provided at the front end of the rear wheel drive shaft S4 meshes with a large bevel gear 27 of the differential device 25. ing. The rotation transmitted to the large bevel gear 27 is
As is well known, the differential case 28, the differential pinion 29, and the differential side gear 30.
Is transmitted to the differential shafts 10 and 10 on both sides via. Each differential shaft 10 is rotatably supported on the side wall of the mission case 4 via a ball bearing 31, and penetrates the side wall to project laterally of the mission case 4.
The rotation of the differential shaft 10 is performed by the reduction gear via the intermediate shaft 32.
It is decelerated in two stages by 33 and 34 and transmitted to the rear axle 11.

As described above, the PTO shaft 13 extends forwards and backwards above the differential shaft 10 along the second main transmission shaft S2 and the sub transmission shaft S3. As shown in FIG. It is linked to the second main transmission shaft S2 via. That is, a gear G ₃ and a gear G ₂ are loosely fitted to the front end portion of the PTO shaft 13 via needle bearings, and these gears G ₃ and G ₂ slide the selector 35 to either side. As a result, the PTO shaft 13 is selectively coupled. The gear G ₃ are meshing with the gear G ₂₃ which is fixed to the second main speed change shaft S2, the gear G ₂ is there What the gear G ₂₂ mesh fixed to the second main speed change shaft S2 as well. A gear G ₁ is further loosely fitted behind the gear G ₂ . This gear G ₁ is the above gear
It meshes with a gear G ₄ formed integrally with G ₂₂ and is selectively connected to the PTO shaft 13 via a selector 36.

With such a configuration, rotation is transmitted to the PTO shaft 13 from the second main transmission shaft S2 at a speed ratio of three steps, but all the gears G ₃ , G ₂ , G ₁ protruding upward from the PTO shaft 13 are PTO shafts. It is provided at the front part of the shaft 13, and the rear part of the shaft is not provided with gears protruding upward therefrom. Since the PTO shaft 13 is disposed at the uppermost part in the mission case 4, the rear portion 4a of the upper wall of the mission case 4 is lowered close to the PTO shaft 13 as shown in FIGS. 4 and 1. Can be formed. By mounting the hydraulic cylinder 14 on the upper surface of the upper wall 4a formed to be low, the height of the upper part of the hydraulic cylinder 14 is also lowered, and therefore the seat 50 above the hydraulic cylinder 14 can be arranged at a low optimum position.

The height H _{1 of the} PTO shaft 13 from the ground (Fig. 1) is regulated to a certain height in relation to the working machine, so this height cannot be lowered. In the present embodiment, since the PTO shaft 13 is arranged at the uppermost part in the mission case 4, the difference h between the upper surface of the case 4 and the above-mentioned constant height H ₁ becomes small, which is also the case. The upper surface of 4 can be as low as possible.

Further, in the present embodiment, the first main transmission shaft S1, the second main transmission shaft S2, the sub transmission shaft S3, and the front wheel drive shaft S5 are arranged below the differential shaft 10 at substantially the same height in the left-right direction in parallel. Has been done. Therefore, the width of the mission case 4 is somewhat wider, but the height of the mission case 4 H ₃ (Fig. 3)
Therefore, the height H ₂ of the bottom wall 4b from the ground can be made sufficiently high to avoid interference with the unevenness and obstacles on the ground during traveling.

As described above, in the present invention, the main transmission and the auxiliary transmission for vehicle speed shifting are arranged side by side in the transmission case arranged below the seat, and the main transmission and A power transmission device for a tractor in which a differential device is arranged between the auxiliary transmission and a first transmission shaft and a second transmission shaft which are parallel to each other and extend in the front-rear direction in the main transmission device.
A main transmission shaft is provided, the first main transmission shaft is extended to the sub transmission, the front wheel drive shaft is extended from the sub transmission to the front end of the transmission case, and both of these shafts are the main transmission shaft. A PTO shaft extending from the front part to the rear end of the transmission case is arranged below the differential shaft extending in a direction perpendicular to the shaft between the transmission and the auxiliary transmission, and above the differential shaft. Since the transmission gear for transmitting rotation to the PTO shaft is provided on the main transmission side, the upper surface of the transmission case mounted on the tractor can be lowered and the rear portion of the upper surface can be further lowered. The upper surface of the Mitchon case can be made lower and the rear portion of the upper surface can be made even lower, so that the height of the seat arranged above the mission case is influenced by the mission case. It becomes higher that no can be placed the sheet to the height position of the optimum. Further, the height of the mission case itself is lowered, and the ground height of the lower surface of the mission case can be set sufficiently high.

[Brief description of drawings]

FIG. 1 is an overall side view of an agricultural tractor to which the present invention is applied, FIG. 2 is a horizontal cross-sectional view showing a power transmission device of the tractor, and FIG. 3 is a vertical cross-sectional view showing an arrangement relationship of shafts in a mission case. FIG. 4 and FIG. 4 are partially enlarged sectional views taken along the line IV-IV in FIG. 1 ... rear wheel, 2 ... front wheel, 3 ... engine, 4 ... mission case, 5 ... reduction gear, 6 ... propeller shaft, 7 ... input shaft, 8 ... main transmission, 9 ... Auxiliary transmission, 10 ... differential shaft, 11 ... rear axle, front wheel,
12 …… Drive propeller shaft, 13 …… PTO shaft, 14 …… Hydraulic cylinder, 15 …… Lift arm, 16 …… Lower arm,
17 …… Main clutch, 18 …… Main clutch shaft, 19 …… First speed hydraulic speed change clutch, 20 …… 4th speed / reverse hydraulic speed change clutch,
21 …… 2-speed hydraulic shift clutch, 22 …… 3-speed hydraulic shift clutch, 23,24 …… selector, 25 …… differential device, 26 …… small bevel gear, 27 …… large bevel gear, 28 …… differential case , 29 …… Differential Pinion,
30 …… Differential side gear, 31 …… Ball bearing, 32
...... Intermediate shaft, 33,34 ...... Reduction gear, 35,36 …… Selector 50 …… Seat, S …… First main shift shaft, S2 …… Second main shift shaft, S3 …… Sub shift shaft, S4 … Rear wheel drive shaft, S5 …… Front wheel drive shaft, SP …… Pump shaft, G …… Gear.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) References Actual public 47-27295 (JP, Y2) Actual public 51-43543 (JP, Y2) Actual public 52-22016 (JP, Y2)

Claims (2)

[Claims] 1. A main transmission and a sub transmission for vehicle speed shifting are arranged side by side in a front and rear direction in a transmission case arranged below a seat, and between the main transmission and the sub transmission. In a power transmission device for a tractor in which a differential device is arranged, a first main transmission shaft and a second main transmission shaft that extend in the front-rear direction and are parallel to each other are arranged in the main transmission device, and the first main transmission shaft is the sub transmission device. A front wheel drive shaft extending from the sub transmission to the front end of the transmission case, and both of these shafts are perpendicular to the shaft between the main transmission and the sub transmission. A PTO shaft is provided below the extending differential shaft and extends from the front part to the rear end of the transmission case above the differential shaft, and a transmission gear for transmitting rotation is transmitted to the PTO shaft. Power transmission device of a tractor, characterized in that provided on the speed apparatus. 2. The power transmission device according to claim 1, wherein the first main transmission shaft, the second main transmission shaft and the front wheel drive shaft are arranged side by side in the left-right direction at substantially the same height.