JP2001105913A - Mounting structure for hydrostatic continuously variable transmission of work vehecle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To mount a hydrostatic continuously variable transmission in a limited space in a work vehicle, while utilizing parts for an existing work vehicle mounting a gear type transmission. SOLUTION: The hydrostatic continuously variable transmission (HST) 20 is disposed between a main clutch 17 disposed at a rear portion of an engine 11 and a transmission case 13. The HST 20 is accommodated in a case 32 to be integral with the transmission case 13, and a reduction gear 40 is disposed on a front face portion of the HST 20. Power of rotating the engine 11 is transmitted to change speed in the HST 20 through the main clutch 17, and is transmitted to a gear type transmission 21 in the transmission case 13 after the speed is reduced in the reduction gear 40.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mounting structure of a hydrostatic continuously variable transmission for a working vehicle, and more particularly, to the mounting of a hydrostatic continuously variable transmission in a working vehicle such as a tractor or a rice transplanter. It is about structure.

[0002]

2. Description of the Related Art In a relatively small work vehicle, there is known one in which the engine power is shifted by a hydrostatic continuously variable transmission (HST). The HST is configured by combining a variable hydraulic pump driven by engine power and a hydraulic motor driven by the hydraulic pump,
By changing the tilt angle of the hydraulic pump, the rotation of the hydraulic motor is steplessly shifted and output. Conventionally, a part of the mission case has a frame structure made of sheet metal,
The HST is housed and mounted in this frame.

However, since the lower part or the side of the frame is open, the oil seals of the input / output shaft and the trunnion shaft of the HST are easily damaged by dust, and the splines of the input / output shaft are also worn by the dust. It's easy to do. Furthermore,
It is difficult to handle when connecting the pipe to the oil port of the HST.

On the other hand, for example, Japanese Patent Application Laid-Open No. 10-33
There is also known an HST-type driving work vehicle described in Japanese Patent No. 9365, in which an HST integrated with a transmission case is housed in a clutch housing, and the HST is not exposed to the outside to prevent damage due to dust. The driving work vehicle uses the engine power output through the clutch as HS.
The transmission is shifted at T and further decelerated by the transmission behind the HST.

[0005]

Here, when an HST is to be mounted on an existing work vehicle equipped with a gear type transmission, the transmission shafts must be arranged in the same manner in order to share a transmission and a rear axle. Must be an array. However, like the driving work vehicle described in the above-mentioned publication, H
If a speed reducer is provided behind the ST, all shaft alignment of the transmission shaft must be performed behind the HST.
A large space is required, and the mission case projects on the floor. In addition, PT
It is difficult to arrange the O-clutch and the like.

Therefore, a technique to be solved for mounting a hydrostatic continuously variable transmission on a work vehicle in a limited space while sharing parts with an existing work vehicle equipped with a gear type transmission. Therefore, an object of the present invention is to solve this problem.

[0007]

SUMMARY OF THE INVENTION The present invention has been proposed to achieve the above object, and has a variable hydraulic pump driven by the rotational power of an engine and a hydraulic motor driven by the hydraulic pump. Wherein the hydrostatic stepless transmission is attached to a rear surface of a rear wall of a clutch housing provided at a rear portion of the engine,
The rotation of the rotating shaft protruding from the clutch is input to the hydraulic pump, and a reduction gear is detachably provided below the rotating shaft and on the front surface of the rear wall of the clutch housing, and the rotation of the output shaft protruding from the hydraulic motor is controlled. Provided is a mounting structure for a hydrostatic continuously variable transmission of a work vehicle configured to transmit the gear to a gear transmission in a transmission case behind the hydrostatic continuously variable transmission after being reduced by the reduction gear. Things.

[0008]

An embodiment of the present invention will be described below in detail with reference to the drawings. FIG. 1 shows a tractor 10 as an example of a work vehicle. An engine 11 is mounted on a front part of the fuselage, covered with a hood 12, a transmission case 13 is attached to a rear part of the fuselage, and a cabin 14 is
And a driver's seat 15 is provided in the cabin 14. A clutch housing 16 is mounted on a rear portion of the engine 11, and a main clutch 17 is provided inside the clutch housing 16.

The main clutch 17 and the transmission case 1
3 is provided with a hydrostatic stepless transmission (HST) 20. The rotational power of the engine 11 is input to the HST 20 via the main clutch 17, and the speed is continuously changed by the HST 20. It is configured to be transmitted to the transmission case 13 later.

In the transmission case 13, the HST2
The power shifted at 0 is split into the power of the traveling system and the power of the PTO system, and the power of the traveling system is shifted by the gear type transmission 21, and the rear wheels 23 are driven via the rear differential device 22. The front wheels 26 are driven from the front wheel transmission shaft 24 via the front differential device 25. On the other hand, the power of the PTO system is output from a PTO output shaft 27 protruding from the rear surface of the transmission case 13.

As shown in FIG. 2 and FIG.
Numeral 0 is attached to the rear surface of the rear wall 16a of the clutch housing, and includes a variable hydraulic pump 30 driven by the power of the engine 11, and a hydraulic motor 31 driven by the hydraulic pump 30, and The HST 20 is accommodated in a case 32 integrally fixed to the transmission case 13, and a front portion of the case 32 is fixed to a rear portion of the clutch housing 16 by bolting.

The rotational power of the engine 11 is supplied to the main clutch 17.
When the main clutch 17 is engaged, the rotational power of the engine 11 is input to the hydraulic pump shaft 33 of the HST 20 via the rotating shaft 17 a projecting rearward from the main clutch 17. If the trunnion shaft 34 is rotated by the operation of the operator, the discharge amount of the hydraulic pump 30 is changed, and the rotation speed of the hydraulic motor 31 changes steplessly. An output shaft 35 of the hydraulic motor projects forward of the HST 20, and a gear 36 fitted to the output shaft 35 and the output shaft 35.
And a gear 38 fitted to the front end of the drive transmission shaft 37 provided in parallel with the gear 38.

The gears 36 and 38 are pivotally mounted from the inside of the clutch housing 16 to a sub case 39 fixed to the front portion of the HST 20. A reduction gear 40 is constituted by a combination of these gears. . The speed reducer 40
Is removably mounted below the rotary shaft 17a of the main clutch and on the front surface of the rear wall 16a of the clutch housing.

A rear portion of the drive transmission shaft 37 extends into the transmission case 13, and a traveling drive shaft 45, a PTO drive shaft 46, and the above-described front wheel transmission shaft 24 are respectively provided in parallel with the drive transmission shaft 37. The transmission case 13 is disposed in parallel with the transmission case 13 in the front-rear direction. The hydraulic pump shaft 33 of the HST 20 penetrates through the hydraulic pump 30 before and after.
The rear end of the hydraulic pump shaft 33 is projected into the transmission case 13 so that the rear end of the hydraulic pump shaft 33
7 is fitted. On the other hand, the gear 50 fitted to the drive transmission shaft 37 and the gear 51 fitted to the travel drive shaft 45 are engaged with each other, and the rotation of the drive transmission shaft 37 is transmitted through the travel drive shaft 45 to the rear gear type transmission. 21.

The power shifted by the HST 20 is decelerated by a speed reducer 40 provided on the front surface of the HST 20 and then travels through a drive transmission shaft 37 in the transmission case 13. 45, and further transmitted to the gear-type transmission 21 for gear shifting. Then, after the power of the traveling system is shifted by the gear type transmission 21, the rear wheels 23 are driven via the rear differential device 22.

As described above, the HST 20 is
The HST 20 is sealed inside, and the intrusion of dust from the outside is extremely small. Further, since the HST 20 is immersed in oil in the case 32, the durability of an oil seal, a spline, and the like is improved. The tank port of the HST 20 can be opened in the transmission case 13 as it is, and the piping of other ports can be simplified. Further, since the transmission 40 is provided in the clutch housing 16 which is the front part of the HST 20, the extra space of the clutch housing 16 can be effectively used.
There are almost no additional components in the transmission case 13 at the rear of ST20, and the transmission case 13 can be downsized. Note that the transmission 40 may be provided not only in the clutch housing 16 but also in the case 32 as long as it is a front portion of the HST 20.

On the other hand, a gear 5 is provided in front of the traveling drive shaft 45.
2 is freely rotatably pivoted, the gear 52 is meshed with the gear 47 of the hydraulic pump shaft 33, and a gear 53 is freely rotatably pivotally mounted on the front of the PTO drive shaft 46. Is meshed with the gear 52. Also, this gear 5
3 is provided with a PTO clutch 55 at the rear thereof.
When the TO clutch 55 is disengaged, the gear 53 idles on the PTO drive shaft 46, and when the PTO clutch 55 is engaged, the PTO drive shaft 46 rotates integrally with the gear 53.
Therefore, when the PTO clutch 55 is engaged, the rotation of the hydraulic pump shaft 33 is transmitted to the PTO drive shaft 46 via the combination of the gears 47, 52, 53, and the PT
The PTO power is output to the PTO output shaft 27 via the O transmission 56. Thus, irrespective of the shift position of the HST 20 and the gear type transmission 21, that is, regardless of the traveling speed, the motor PTO (live P
TO) power can be obtained.

Here, the gear type transmission 21 is provided with a front wheel drive gear 60, and a counter gear 61 pivotally mounted on the PTO drive shaft 46 for free rotation meshes with the front wheel drive gear 60. I have. The counter gear 61 idles on the PTO drive shaft 46 integrally with the speed-increasing gear 62 and the reduction gear 63, respectively, and is driven by the switching operation of the four-wheel drive switching clutch 65 provided at the rear of the front wheel transmission shaft 24. Gear 6
0 rotation is transmitted to the front wheel transmission shaft 24 via the speed increasing gear 62 or rotation of the front wheel drive gear 60 is transmitted to the front wheel transmission shaft 24 via the reduction gear 63. It is configured to do so.

As described above, the counter gear 61 that receives the rotation of the front wheel drive gear 60 includes the speed-up gear 62 and the reduction gear 6.
3 is pivotally mounted on the PTO drive shaft 46 together with
It is possible to switch between the normal four-wheel drive mode and the front wheel speed-up four-wheel drive mode without separately providing a counter shaft, so that the device becomes compact, the transmission case 13 can be downsized, and the cost due to the reduction in the number of parts is reduced. Down can be planned.

The present invention can be variously modified without departing from the spirit of the present invention, and it goes without saying that the present invention extends to the modified ones.

[0021]

As described in detail in the above embodiment, the present invention provides a hydrostatic continuously variable transmission (HST) between a main clutch of a work vehicle and a transmission case, and
By providing a speed reducer on the front of ST, the HST
After being decelerated by this speed reducer, the power shifted by is transmitted to the gear type transmission in the transmission case. Therefore, when the HST is to be mounted on the existing work vehicle, the transmission shaft and the rear axle can be shared by disposing the transmission shafts in the same arrangement without additionally equipping the transmission case with a reduction gear. Also,
The main frame of the vehicle body including the clutch housing, the cover of the HST, and the transmission case can be set to be short while sharing each part.

Thus, it is possible to mount the HST on the work vehicle in a limited space while sharing parts with the existing work vehicle equipped with the gear type transmission.

[Brief description of the drawings]

 The figure shows an embodiment of the present invention.

FIG. 1 is a side view of a tractor.

FIG. 2 is a developed longitudinal sectional side view showing an arrangement configuration of a transmission shaft from a clutch housing to a transmission case.

FIG. 3 is a sectional view taken along the line AB in FIG. 2;

FIG. 4 is a sectional view taken along the line CC of FIG. 2;

FIG. 5 is a sectional view taken along line DD of FIG. 2;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Tractor 11 Engine 13 Transmission case 17 Main clutch 20 Hydrostatic continuously variable transmission (HST) 21 Gear type transmission 30 Hydraulic pump 31 Hydraulic motor 32 Case 40 Reduction gear

 ────────────────────────────────────────────────── ─── Continued on the front page F term (reference) 2B062 AA14 AA20 BA05 BA06 BA07 BA18 3D039 AA02 AA03 AA04 AB11 AC02 AC13 AC21 AC33 AC37 AC64 AC79 AD06 AD33 AD53 3D042 AA06 AB11 BA02 BA04 BA13 BB03

Claims (1)

[Claims] 1. A hydrostatic stepless transmission having a variable hydraulic pump driven by rotational power of an engine and a hydraulic motor driven by the hydraulic pump. The transmission is attached to a rear surface of a rear wall of a clutch housing provided at a rear portion of the engine, and inputs rotation of a rotation shaft protruding from a clutch to the hydraulic pump,
A reduction gear is detachably provided below the rotation shaft and on the front surface of a rear wall of the clutch housing, and after the rotation of the output shaft protruding from the hydraulic motor is reduced by the reduction gear, the hydrostatic stepless transmission is provided. An installation structure for a hydrostatic continuously variable transmission for a work vehicle, wherein the transmission is transmitted to a gear type transmission in a rear transmission case.