Transmission for tractor

Abstract

A transmission for a tractor has a forward/reverse transmission unit for selectively changing a rotational direction of power of a first shaft connected with an engine and transmitting the power to a second shaft connected with an axle shaft, a main transmission unit installed between the second shaft and the axle shaft and having a plurality of gears to speed-change the power transmitted from the second shaft in four-speed, and a sub-transmission unit installed between the main transmission unit and the axle shaft and having a plurality of gears to speed-change again the power transmitted from the main transmission unit in four-speed. The transmission realizes forward/reverse 16-speed while having a compact structure.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects, features and advantages of the present invention will be more apparent from the following detailed description taken in conjunction with the accompanying drawings, in which:

FIG. 1 is a schematic view showing a structure of a general tractor;

FIG. 2 is a view showing an entire structure of a transmission for a tractor according to the present invention;

FIG. 3 is an enlarged view of a main transmission unit of the transmission for tractor of FIG. 2; and

FIG. 4 is an enlarged view of a sub-transmission unit of the transmission for tractor of FIG. 2.

Claims

1. A transmission for a tractor comprising: a forward/reverse transmission unit for selectively changing a rotational direction of power of a first shaft connected with an engine and transmitting the power to a second shaft connected with an axle shaft;a main transmission unit installed between the second shaft and the axle shaft and having a plurality of gears to speed-change the power transmitted from the second shaft in four-speed; anda sub-transmission unit installed between the main transmission unit and the axle shaft and having a plurality of gears to speed-change again the power transmitted from the main transmission unit in four-speed.

2. The transmission as claimed in claim 1, wherein the forward/reverse transmission unit includes: a forward clutch section and a reverse clutch section both installed in parallel on the first shaft;a first gear coupled to one side of the forward clutch section to be selectively connected with the first shaft by an operation of the forward clutch section;a second gear installed on the second shaft and engaged with the first gear;a third gear coupled to one side of the reverse clutch section to be selectively connected with the first shaft by an operation of the reverse clutch section;a fourth gear engaged with the third gear; anda fifth gear installed on the second shaft and engaged with the fourth gear.

3. The transmission as claimed in claim 1, wherein the main transmission unit includes: a third shaft connected with the second shaft;a fourth shaft selectively connected with the third shaft;a fifth shaft arranged parallel to the third and fourth shafts;a sixth gear installed on the third shaft;a seventh gear, an eighth gear, and a ninth gear installed in parallel on the fourth shaft;a tenth gear installed on the fifth shaft and engaged with the sixth gear;an eleventh gear installed on the fifth shaft and engaged with the seventh gear;a twelfth gear installed on the fifth shaft and engaged with the eighth gear; anda thirteenth gear installed on the fifth shaft and engaged with the ninth gear.

4. The transmission as claimed in claim 3, wherein the main transmission unit further includes: a first coupling gear installed on one side of the sixth gear;a second coupling gear installed on one side of the seventh gear opposite to the first coupling gear;a first hub linearly movably installed on the fourth shaft to be selectively connected with the first or second coupling gear;a third coupling gear installed on one side of the eighth gear;a fourth coupling gear installed on one side of the ninth gear opposite to the third coupling gear; anda second hub linearly movably installed on the fourth shaft to be selectively connected with the third or fourth coupling gear.

5. The transmission as claimed in claim 3, wherein the sub-transmission unit includes: a sixth shaft arranged parallel to the fourth shaft and receiving power from the fourth shaft;a seventh shaft arranged coaxially with the fourth shaft;an eighth shaft selectively connected with the sixth shaft;a ninth shaft having one end selectively connected with the seventh shaft and the other end connected with the axle shaft;a fourteenth gear installed on a distal end of the fourth shaft;an eighteenth gear installed on one end of the sixth shaft and engaged with the fourteenth gear;a nineteenth gear installed on the other end of the sixth shaft;a fifteenth gear installed on one end of the seventh shaft and engaged with the nineteenth gear;a sixteenth gear installed on the other end of the seventh shaft;a twentieth gear installed on one end of the eighth shaft and engaged with the sixteenth gear;a twenty-first gear installed on the other end of the eighth shaft; anda seventeenth gear installed on the ninth shaft and engaged with the twenty-first gear.

6. The transmission as claimed in claim 5, wherein the sub-transmission unit further includes: a fifth coupling gear installed on one side of the fourteenth gear;a sixth coupling gear installed on one side of the fifteenth gear opposite to the fifth coupling gear;a third hub linearly movably installed on the ninth shaft to be selectively connected with the fifth or sixth coupling gear;a seventh coupling gear installed on one side of the nineteenth gear;an eighth coupling gear installed on one side of the twentieth gear opposite to the seventh coupling gear; anda fourth hub linearly movably installed on the eighth shaft to be selectively connected with the seventh or sixth coupling gear.

7. The transmission as claimed in claim 2, wherein the forward/reverse clutch sections are installed on the second shaft.