1. A combine harvester comprising: a threshing apparatus; 5 a grain tank for accumulating grains threshed by the threshing apparatus; a grain conveyance mechanism for conveying grains from the threshing apparatus to the grain tank; a pressed portion that is subjected to a pressing force applied by grains in a conveyance path in the grain conveyance mechanism; 10 a load detector for detecting the pressing force exerted on the pressed portion; and a yield evaluator for evaluating an amount of conveyed grain based on a detection signal from the load detector.

2. The combine harvester according to claim 1, further comprising: 15 a grain discharge apparatus provided in an end area of the grain conveyance mechanism, the grain discharge apparatus having a discharge case provided with a grain discharge opening, and a discharge rotor rotatably arranged in the discharge case, wherein the pressed portion is subjected to a pressing force applied by grains before the grains are discharged by the discharge rotor. 20

3. The combine harvester according to claim 2, wherein the pressed portion is subjected to a pressing force applied by grains immediately before the grains are discharged by the discharge rotor. 25 4. The combine harvester according to claim 3, wherein a plate-shaped member that serves as the pressed portion is attached to the discharge case at a position immediately forward of the grain discharge opening in a direction in which grains are conveyed, and wherein the pressing force applied by grains passing between the discharge rotor and the pressed portion is exerted on the pressed portion. 30 30

5. The combine harvester according to claim 4, wherein the plate-shaped member is formed as a pressure sensitive plate extending in a rotational direction of the discharge rotor, and the load detector is a load cell provided in the pressure sensitive plate. 5 6. The combine harvester according to claim 4 or 5, wherein the plate-shaped member spans one end portion and another end portion of the grain discharge opening in a rotation axis direction of the discharge rotor.

7. The combine harvester according to any one of claims 3 to 6, 10 wherein the discharge case is a cylindrical body having a cylindrical portion with a center that is a rotation axis of the discharge rotor, the cylindrical body extending along the rotation axis, the grain discharge opening is provided in a portion of an inner circumferential face of the cylindrical body, and the pressed portion is provided in a circumferential face portion of the inner 15 circumferential face, the circumferential face portion being located forward of the grain discharge opening in a rotational direction of the discharge rotor.

8. The combine harvester according to any one of claims 2 to 7, wherein the yield evaluator evaluates the amount of conveyed grain per rotation cycle of the discharge rotor, based on the 20 detection signal from the load detector in the rotation cycle.

9. The combine harvester according to claim 8, wherein the yield evaluator evaluates the amount of conveyed grain per unit of travel distance by integrating a largest value of the detection signal from the load detector obtained every rotation cycle, during a period of time it takes for the 25 combine harvester to travel the unit of travel distance.

10. The combine harvester according to any one of claims 2 to 9, wherein the discharge rotor is a rotary blade constituted by a rotary shaft and a blade provided on the rotary shaft, and the rotary blade has a grain pushing face for pushing out grains in a rotational direction. 30 31

11. The combine harvester according to claim 10, further comprising: a rotation angle sensor for detecting a rotation angle of the rotary blade, wherein the rotation angle sensor is a sensor that detects a specific point in a circumferential direction of the rotary blade, and 5 the yield evaluator calculates a rotation cycle of the discharge rotor based on the specific point in the circumferential direction, and regards a period, in which a largest value of the detection signal from the load detector is generated in the rotation cycle of the discharge rotor, as a period evaluated by the yield evaluator. 10 12. The combine harvester according to claim 11, wherein, at a time point near a middle point in a period from when a pulse signal that is based on the detection signal from the rotation angle sensor is generated until the next pulse signal is generated, the blade passes the pressed portion, and the detection signal from the load detector takes its largest value. 15 13. A grain yield management system for a combine harvester, the system comprising: a threshing apparatus; a grain accumulator; a grain conveyance mechanism for conveying grains from the threshing apparatus to the grain accumulator; 20 a conveyed grain measurement apparatus for measuring an amount of grain conveyed by the grain conveyance mechanism during travel for reaping grain culms; an accumulated grain measurement apparatus for measuring an amount of grain accumulated in the grain accumulator; and an information generator for generating grain yield information regarding a field 25 subjected to harvesting work, based on conveyed grain measurement data outputted from the conveyed grain measurement apparatus and accumulated grain measurement data outputted from the accumulated grain measurement apparatus.

14. The grain yield management system for a combine harvester according to claim 13, 30 wherein the accumulated grain measurement apparatus continuously performs 32 measurement during travel for reaping grain culms, and the information generator includes a yield distribution calculator for calculating a distribution of a grain yield per parcel unit in the field based on the conveyed grain measurement data. 5

15. The grain yield management system for a combine harvester according to claim 13 or 14, wherein the information generator includes a corrector for correcting the conveyed grain measurement data, based on a comparative evaluation value that is obtained by comparing and evaluating integrated data obtained by integrating the conveyed grain measurement data with the 10 accumulated grain measurement data.

16. The grain yield management system for a combine harvester according to claim 15, wherein the corrector corrects each piece of the conveyed grain measurement data so that a grain yield, obtained by integrating a conveyed grain measurement data group outputted until the 15 accumulated grain measurement data is outputted, is equal to a grain yield that is based on the accumulated grain measurement data.

17. The grain yield management system for a combine harvester according to any one of claims 13 to 16, wherein the information generator is constructed in a computer system in a remote 20 place, the computer system being capable of wireless data communication with a combine harvester.

WE CLAIM:
1. A combine harvester comprising:
a threshing apparatus;
5 a grain tank for accumulating grains threshed by the threshing apparatus;
a grain conveyance mechanism for conveying grains from the threshing apparatus to the grain tank;
a pressed portion that is subjected to a pressing force applied by grains in a conveyance
path in the grain conveyance mechanism;
10 a load detector for detecting the pressing force exerted on the pressed portion; and
a yield evaluator for evaluating an amount of conveyed grain based on a detection signal from the load detector.
2. The combine harvester according to claim 1, further comprising:
15 a grain discharge apparatus provided in an end area of the grain conveyance mechanism,
the grain discharge apparatus having a discharge case provided with a grain discharge opening, and a discharge rotor rotatably arranged in the discharge case,
wherein the pressed portion is subjected to a pressing force applied by grains before the grains are discharged by the discharge rotor.
20
3. The combine harvester according to claim 2, wherein the pressed portion is subjected to a
pressing force applied by grains immediately before the grains are discharged by the discharge
rotor.
25 4. The combine harvester according to claim 3, wherein a plate-shaped member that serves
as the pressed portion is attached to the discharge case at a position immediately forward of the grain discharge opening in a direction in which grains are conveyed, and
wherein the pressing force applied by grains passing between the discharge rotor and the pressed portion is exerted on the pressed portion.
30
30

5. The combine harvester according to claim 4, wherein the plate-shaped member is formed
as a pressure sensitive plate extending in a rotational direction of the discharge rotor, and the load detector is a load cell provided in the pressure sensitive plate.
5 6. The combine harvester according to claim 4 or 5, wherein the plate-shaped member spans
one end portion and another end portion of the grain discharge opening in a rotation axis direction of the discharge rotor.
7. The combine harvester according to any one of claims 3 to 6,
10 wherein the discharge case is a cylindrical body having a cylindrical portion with a center
that is a rotation axis of the discharge rotor, the cylindrical body extending along the rotation axis,
the grain discharge opening is provided in a portion of an inner circumferential face of the cylindrical body, and
the pressed portion is provided in a circumferential face portion of the inner 15 circumferential face, the circumferential face portion being located forward of the grain discharge opening in a rotational direction of the discharge rotor.
8. The combine harvester according to any one of claims 2 to 7, wherein the yield evaluator
evaluates the amount of conveyed grain per rotation cycle of the discharge rotor, based on the
20 detection signal from the load detector in the rotation cycle.
9. The combine harvester according to claim 8, wherein the yield evaluator evaluates the
amount of conveyed grain per unit of travel distance by integrating a largest value of the detection
signal from the load detector obtained every rotation cycle, during a period of time it takes for the
25 combine harvester to travel the unit of travel distance.
10. The combine harvester according to any one of claims 2 to 9, wherein the discharge rotor
is a rotary blade constituted by a rotary shaft and a blade provided on the rotary shaft, and the
rotary blade has a grain pushing face for pushing out grains in a rotational direction.
30
31

11. The combine harvester according to claim 10, further comprising:
a rotation angle sensor for detecting a rotation angle of the rotary blade,
wherein the rotation angle sensor is a sensor that detects a specific point in a
circumferential direction of the rotary blade, and
5 the yield evaluator calculates a rotation cycle of the discharge rotor based on the specific
point in the circumferential direction, and regards a period, in which a largest value of the detection
signal from the load detector is generated in the rotation cycle of the discharge rotor, as a period
evaluated by the yield evaluator.
10 12. The combine harvester according to claim 11, wherein, at a time point near a middle
point in a period from when a pulse signal that is based on the detection signal from the rotation angle sensor is generated until the next pulse signal is generated, the blade passes the pressed portion, and the detection signal from the load detector takes its largest value.
15 13. A grain yield management system for a combine harvester, the system comprising:
a threshing apparatus; a grain accumulator;
a grain conveyance mechanism for conveying grains from the threshing apparatus to the
grain accumulator;
20 a conveyed grain measurement apparatus for measuring an amount of grain conveyed by
the grain conveyance mechanism during travel for reaping grain culms;
an accumulated grain measurement apparatus for measuring an amount of grain accumulated in the grain accumulator; and
an information generator for generating grain yield information regarding a field 25 subjected to harvesting work, based on conveyed grain measurement data outputted from the conveyed grain measurement apparatus and accumulated grain measurement data outputted from the accumulated grain measurement apparatus.
14. The grain yield management system for a combine harvester according to claim 13,
30 wherein the accumulated grain measurement apparatus continuously performs
32

measurement during travel for reaping grain culms, and
the information generator includes a yield distribution calculator for calculating a distribution of a grain yield per parcel unit in the field based on the conveyed grain measurement data. 5
15. The grain yield management system for a combine harvester according to claim 13 or 14,
wherein the information generator includes a corrector for correcting the conveyed grain
measurement data, based on a comparative evaluation value that is obtained by comparing and evaluating integrated data obtained by integrating the conveyed grain measurement data with the 10 accumulated grain measurement data.
16. The grain yield management system for a combine harvester according to claim 15,
wherein the corrector corrects each piece of the conveyed grain measurement data so that a grain
yield, obtained by integrating a conveyed grain measurement data group outputted until the
15 accumulated grain measurement data is outputted, is equal to a grain yield that is based on the accumulated grain measurement data.
17. The grain yield management system for a combine harvester according to any one of
claims 13 to 16, wherein the information generator is constructed in a computer system in a remote
20 place, the computer system being capable of wireless data communication with a combine harvester.