Semi tracked-type working vehicle
A semicrawler-type working vehicle is provided having a vehicle body ( 3 ), a front steering control wheel ( 7 ) arranged at a front side of the vehicle body, a drive shaft ( 26 ) and a pivot shaft ( 22 ) arranged at a rear side of the vehicle body, and a semicrawler unit ( 2 ) driven by the drive shaft. The semicrawler-type working vehicle comprises: a track frame ( 16 ) by which the semicrawler unit ( 2 ) is supported via the pivot shaft ( 22 ) so as to be pivotable relative to the vehicle body ( 3 ); a drive wheel ( 11 ) arranged on the drive shaft ( 26 ); a front driven wheel ( 12 ) and a rear driven wheel ( 13 ) that are supported by the track frame ( 16 ) such that a horizontal distance from the drive wheel ( 11 ) to the front driven wheel ( 12 ) is longer than a horizontal distance from the drive wheel ( 11 ) to the rear driven wheel ( 13 ); and a crawler belt ( 15 ) that is wound around the drive wheel ( 11 ), the front driven wheel ( 12 ), and the rear driven wheel ( 13 ). The pivot shaft ( 22 ) is displaced forward than a vertical line that runs through a center of the drive wheel ( 11 ).
1. A semicrawler-type working vehicle having a vehicle body, a front steering control wheel arranged at a front position of the vehicle body, a drive shaft and a pivot shaft arranged at rear positions of the vehicle body, and a semicrawler unit driven by the drive shaft, the semicrawler-type working vehicle comprising:
a track frame supporting the semicrawler unit relative to the vehicle body by means of the pivot shaft;
a drive wheel arranged on the drive shaft;
a front driven wheel and a rear driven wheel which are supported by the track frame such that a horizontal distance from the drive wheel to the front driven wheel is longer than a horizontal distance from the drive wheel to the rear driven wheel and such that the drive wheel is positioned between the front driven wheel and the rear driven wheel in a fore and aft direction of the vehicle body;
a crawler belt wound around the drive wheel, the front driven wheel, and the rear driven wheel; and
a single axis defined by the pivot shaft, the track frame being pivotal about the single axis relative to the vehicle body;
wherein the pivot shaft is displaced forward from a vertical line that runs through a center of the drive wheel.
2. The semicrawler-type working vehicle according to claim 1 , wherein the track frame is pivotably supported relative to the pivot shaft and a position of the track frame is adjustable in a longitudinal direction of the vehicle.
3. The semicrawler-type working vehicle according to claim 2 , further comprising a pivot shaft bearing member for pivotably receiving the pivot shaft, the pivot shaft bearing member being adapted to adjust a position thereof in the longitudinal direction relative to the track frame.
4. The semicrawler-type working vehicle according to claim 1 , wherein the pivot shaft is adapted to adjust a position thereof relative to the vehicle body in the longitudinal direction of the vehicle.
5. A semicrawler-type working vehicle having a vehicle body, a front steering control wheel arranged at a front position of the vehicle body, a drive shaft and a pivot shaft arranged at rear positions of the vehicle body, and a semicrawler unit driven by the drive shaft, the semicrawler-type working vehicle comprising:
a track frame pivotably supporting the semicrawler unit relative to the vehicle body by means of the pivot shaft;
a drive wheel arranged on the drive shaft;
a front driven wheel and a rear driven wheel which are supported by the track frame such that a horizontal distance from the drive wheel to the front driven wheel is longer than a horizontal distance from the drive wheel to the rear driven wheel and such that the drive wheel is positioned between the front driven wheel and the rear driven wheel in a fore and aft direction of the vehicle body;
a crawler belt wound around the drive wheel, the front driven wheel, and the rear driven wheel; and
a guide wheel arranged on the track frame, to regulate a lateral displacement of the crawler belt between the drive wheel and the rear driven wheel, and between the drive wheel and the front driven wheel,
wherein the pivot shaft is displaced forward from a vertical line that runs through a center of the drive wheel.
6. A semicrawler-type working vehicle having a vehicle body, a front steering control wheel arranged at a front position of the vehicle body, a drive shaft and a pivot shaft arranged at rear positions of the vehicle body, and a semicrawler unit driven by the drive shaft, the semicrawler-type working vehicle comprising:
a track frame pivotably supporting the semicrawler unit relative to the vehicle body by means of the pivot shaft;
a drive wheel arranged on the drive shaft;
a front driven wheel and a rear driven wheel which are supported by the track frame such that a horizontal distance from the drive wheel to the front driven wheel is longer than a horizontal distance from the drive wheel to the rear driven wheel and such that the drive wheel is positioned between the front driven wheel and the rear driven wheel in a fore and aft direction of the vehicle body;
a crawler belt wound around the drive wheel, the front driven wheel, and the rear driven wheel; and
a plurality of rollers positioned between the front driven wheel and the drive wheel, and ground-contacting lugs of the crawler belt, a pitch between adjacent rollers is longer than a pitch of adjacent ground-contacting lugs by 1/N (where N is the number of the rollers),
wherein the pivot shaft is displaced forward from a vertical line that runs through a center of the drive wheel.
7. A semicrawler-type working vehicle having a vehicle body, a front steering control wheel arranged at a front position of the vehicle body, a drive shaft and a pivot shaft arranged at rear positions of the vehicle body, and a semicrawler unit driven by the drive shaft, the semicrawler-type working vehicle comprising:
a track frame pivotably supporting the semicrawler unit relative to the vehicle body by means of the pivot shaft;
a drive wheel arranged on the drive shaft;
a front driven wheel and a rear driven wheel which are supported by the track frame such that a horizontal distance from the drive wheel to the front driven wheel is longer than a horizontal distance from the drive wheel to the rear driven wheel and such that the drive wheel is positioned between the front driven wheel and the rear driven wheel in a fore and aft direction of the vehicle body;
a crawler belt wound around the drive wheel, the front driven wheel, and the rear driven wheel; and
a plurality of rollers positioned between the front driven wheel and the drive wheel, an outer perimeter each of the rollers is covered with rubber,
wherein the pivot shaft is displaced forward from a vertical line that runs through a center of the drive wheel.
8. A semicrawler-type working vehicle having a vehicle body, a front steering control wheel arranged at a front position of the vehicle body, a drive shaft and a pivot shaft arranged at rear positions of the vehicle body, and a semicrawler unit driven by the drive shaft, the semicrawler-type working vehicle comprising:
a track frame pivotably supporting the semicrawler unit relative to the vehicle body by means of the pivot shaft, wherein the pivot shaft includes two short shafts aligned on a same axis;
a drive wheel arranged on the drive shaft;
a front driven wheel and a rear driven wheel which are supported by the track frame such that a horizontal distance from the drive wheel to the front driven wheel is longer than a horizontal distance from the drive wheel to the rear driven wheel and such that the drive wheel is positioned between the front driven wheel and the rear driven wheel in a fore and aft direction of the vehicle body; and
a crawler belt wound around the drive wheel, the front driven wheel, and the rear driven wheel,
wherein the pivot shaft is displaced forward from a vertical line that runs through a center of the drive wheel.
9. The semicrawler-type working vehicle according to claim 1 , further comprising a guide wheel arranged on the track frame, to regulate a lateral displacement of the crawler belt between the drive wheel and the rear driven wheel, and between the drive wheel and the front driven wheel.
10. The semicrawler-type working vehicle according to claim 1 , further comprising a plurality of rollers positioned between the front driven wheel and the drive wheel, and ground-contacting lugs of the crawler belt, a pitch between adjacent rollers is longer than a pitch of adjacent ground-contacting lugs by 1/N (where N is the number of the rollers).
11. The semicrawler-type working vehicle according to claim 1 , further comprising a plurality of rollers positioned between the front driven wheel and the drive wheel, an outer perimeter each of the rollers is covered with rubber.
12. The semicrawler-type working vehicle according to claim 1 , wherein the pivot shaft includes two short shafts aligned on a same axis.