Combine harvester

Abstract

The present invention provides a combine harvester that can detect an abnormality in the operation of a moisture sensor and eliminate the abnormality. In order to detect an abnormality of roll locking in which the electrode roller of the moisture sensor cannot rotate properly, the motor drive current supplied to the DC motor that rotates the electrode roller of the moisture sensor is detected. Then, it is determined whether the motor drive current is greater than a predetermined threshold (S11). When it is determined that the motor drive current is greater than the threshold (S11: Yes), the electrode roller stops (S12). Then, when the electrode roller has rotated forward before stopping (S13: Yes), the DC motor is controlled to reverse the electrode roller within a predetermined normal time (S14).

Description

Technical Field

[0001] The present invention relates to a combine harvester. Background Art

[0002] In a combine harvester, the roots of the cereal culms standing upright in the field are harvested by a harvesting device, and the harvested cereal culms are conveyed from the harvesting device to a threshing device, and the cereal culms are threshed by the threshing device. Cereal grains such as paddy rice detached from the cereal culms are conveyed from the threshing device to a discharge portion provided above the grain tank, and are discharged into the grain tank from the discharge portion.

[0003] First, there is a combine harvester equipped with a moisture sensor (moisture meter) for measuring the moisture content of the harvested cereal grains. The moisture sensor is structured, for example, to rotate a pair of electrode rollers in the direction of rolling in the cereal grains, crush the cereal grains between the electrode rollers, and detect the resistance value between the electrode rollers at this time. The moisture content of the cereal grains can be determined from this resistance value (for example, refer to Patent Document 1).

[0004] Second, there is a combine harvester equipped with a moisture sensor (moisture meter) for measuring the moisture content of the harvested cereal grains. In a combine harvester equipped with a moisture sensor, for example, the following structure has been proposed: the discharge portion is arranged at an upper position on the left side plate of the grain tank, which is closer to the front side than the center in the front-rear direction, the moisture sensor is arranged at the upper left end of the rear surface of the grain tank, a rotating body rotating at the discharge portion makes the cereal grains splash in a substantially horizontal direction, and the splashed cereal grains are received by the moisture sensor (for example, refer to Patent Document 1).

[0005] Prior Art Documents

[0006] Patent Documents

[0007] Patent Document 1: Japanese Patent No. 6451513 Gazette Summary of the Invention

[0008] Problems to be Solved by the Invention

[0009] Therefore, in the first aspect of the present invention, when measuring the moisture content of cereal grains containing a large amount of moisture, sometimes the crushed cereal grains adhere to the electrode rollers, and the cereal grains do not fall off from the electrode rollers and remain in an adhered state to the electrode rollers. In this state, if the moisture content of the cereal grains is measured next time, the moisture content cannot be accurately measured. In addition, if this state is left as it is, the cereal grains are fixed to the electrode rollers, and there is a possibility that the electrode rollers cannot rotate well.

[0010] An object of the first aspect of the present invention is to provide a combine harvester capable of detecting an abnormality in the operation of a moisture sensor and eliminating the abnormality.

[0011] Solutions to the Problems

[0012] To achieve the above object, the combine harvester according to the first aspect of the present invention includes: a moisture sensor having a pair of electrode rollers. The pair of electrode rollers rotate forward in a direction in which grains are rolled between the electrode rollers, crush the grains between the electrode rollers, and perform a detection operation of detecting the resistance value between the electrode rollers during the crushing. By reversing the pair of electrode rollers, a cleaning operation of cleaning the surfaces of the electrode rollers is performed; and a control device that controls the operation of the moisture sensor. During the rotation of the pair of electrode rollers, the control device performs a determination for detecting an abnormality of the moisture sensor. When an abnormality of the moisture sensor is detected through this determination, in order to eliminate the abnormality, the moisture sensor is made to perform an abnormality elimination operation.

[0013] According to this structure, during the rotation of the pair of electrode rollers of the moisture sensor, by performing a determination for detecting an abnormality of the moisture sensor, the abnormality of the moisture sensor can be detected. Moreover, when an abnormality of the moisture sensor is detected, the abnormality can be eliminated through the abnormality elimination operation of the moisture sensor.

[0014] The control device may also determine whether the drive current of the motor that rotates the pair of electrode rollers exceeds a threshold value, and detect an abnormality of the moisture sensor based on the determination that the threshold value is exceeded. Through this method, an abnormality in which the electrode rollers cannot rotate well due to grains being fixed to the electrode rollers can be detected.

[0015] Moreover, preferably, when the control device detects an abnormality during the forward rotation of the pair of electrode rollers through this method, as an abnormality elimination operation, after stopping the pair of electrode rollers, the moisture sensor is made to perform a cleaning operation. Thereby, the elimination of the abnormality caused by the removal of the grains fixed to the electrode rollers can be achieved. In addition, the elimination of the abnormality caused by the removal of foreign objects such as cut straws caught between the electrode rollers can be achieved.

[0016] Alternatively, when the control device detects an abnormality during the reverse rotation of the pair of electrode rollers through this method, the pair of electrode rollers may be stopped and an abnormality alarm may be issued.

[0017] The control device may also determine whether the resistance value between the electrode rollers during the cleaning operation is an abnormal value, and detect an abnormality of the moisture sensor based on the determination that the resistance value is an abnormal value. Through this method, an abnormality (roller blockage) in which grains adhere to the electrode rollers because the grains do not fall off the electrode rollers can be detected.

[0018] Moreover, preferably, when the control device detects an abnormality during the cleaning operation within a normal time through this method, as an abnormality elimination operation, the cleaning operation is made to continue for a time longer than the normal time. Thereby, the elimination of the abnormality caused by removing grains from the electrode rollers can be achieved.

[0019] In addition, the control device can issue an abnormal alarm when the abnormality of the moisture sensor is detected multiple times.

[0020] Advantages of the Invention

[0021] According to the present invention, it is possible to detect the abnormality of the operation of the moisture sensor and eliminate the abnormality.

[0022] Problems to be Solved by the Invention

[0023] In the second aspect of the present invention, the scattering distance of the grains containing a large amount of moisture scattered from the discharge part of the grains is short. Considering this situation, if the position of the moisture sensor is lowered, the grains containing a large amount of moisture can also reach the moisture sensor well.

[0024] However, when the position of the moisture sensor is low, if the grains are stored in the grain box, the moisture sensor will be buried in the grains. In the state where the moisture sensor is buried in the grains, the grains cannot be discharged from the moisture sensor, and since the grains clog the moisture sensor, there will be a situation where the moisture sensor does not operate well even when the moisture sensor is activated, and it is possible to falsely report the abnormality of the moisture sensor.

[0025] An object of the second aspect of the present invention is to provide a combine harvester that can prevent the following situation: when the moisture sensor is buried in the grains, the moisture sensor does not operate well even when it is activated.

[0026] Solutions for Solving the Problems

[0027] To achieve the above object, the combine harvester of the present invention includes: a grain box for storing grains; a moisture sensor arranged to receive the grains discharged into the grain box and used to measure the moisture content of the grains; and a control device that prohibits the operation of the moisture sensor according to the pre-stage of the buried state, that is, the buried dangerous state, in which the moisture sensor is detected to be buried in the grains stored in the grain box.

[0028] According to this structure, the moisture sensor for measuring the moisture content of the grains receives the grains discharged into the grain box. As the discharge of the grains into the grain box progresses, if the moisture sensor reaches the state before the state of being buried in the grains stored in the grain box, the operation of the moisture sensor is prohibited. Thus, even if the moisture sensor becomes buried in the grains, the operation of the moisture sensor is originally prohibited and the moisture sensor is not instructed to operate, so it is possible to prevent the situation where the moisture sensor does not operate well even when it is activated. As a result, it is possible to suppress false reporting of the abnormality of the moisture sensor.

[0029] Alternatively, the moisture sensor may include a pair of electrode rollers. The pair of electrode rollers rotate forward in a direction in which grains are rolled between the electrode rollers, crush the grains between the electrode rollers, detect the resistance value between the electrode rollers during the crushing, and perform a detection operation of outputting a value corresponding to the moisture content of the grains. The pair of electrode rollers rotate in reverse to perform a cleaning operation of cleaning the surfaces of the electrode rollers. In this case, preferably, the control device prohibits both the detection operation and the cleaning operation according to the detected state of the risk of burial.

[0030] Preferably, according to the situation where the risk of burial is eliminated, the control device releases the operation prohibition of the moisture sensor and causes the moisture sensor to perform a cleaning operation.

[0031] Thereby, clogging of grains in the moisture sensor can be eliminated, and good operation of the moisture sensor can be ensured.

[0032] The combine harvester may also have the following structure: It further includes an arrival sensor that detects the situation where the grains stored in the grain tank reach a detection position set at a position lower than the position of the moisture sensor. In this case, the control device may also detect the state where the grains reach the detection position detected by the arrival sensor as a risk of burial state.

[0033] Advantages of the Invention

[0034] According to the present invention, it is possible to prevent the following situation from occurring: When the moisture sensor is buried in grains, even if the moisture sensor is operated, it will not operate well. Brief Description of the Drawings

[0035] First Embodiment

[0036] Figure 1 It is a right view of a combine harvester according to an embodiment of the present invention.

[0037] Figure 2 It is a view of observing the inside of the grain tank from the right side.

[0038] Figure 3 It is a perspective view of the upper front end inside the grain tank.

[0039] Figure 4 It is a perspective view of the rear end inside the grain tank.

[0040] Figure 5 It is a perspective view of the moisture sensor.

[0041] Figure 6 It is a block diagram showing the main part of the electrical structure of the combine harvester.

[0042] Figure 7 It is a flowchart showing the process of driving control of the moisture sensor.

[0043] Figure 8 It is a flowchart showing the process of the first abnormality elimination process.

[0044] Figure 9 It is a flowchart showing the process of the second abnormality elimination process.

[0045] Second Embodiment

[0046] Figure 10 It is a right view of a combine harvester according to an embodiment of the present invention.

[0047] Figure 11 It is a view of the inside of the grain tank observed from the right side.

[0048] Figure 12 It is a perspective view of the upper front part inside the grain tank.

[0049] Figure 13 It is a perspective view of the rear end part inside the grain tank.

[0050] Figure 14 It is a perspective view of the moisture sensor.

[0051] Figure 15 It is a block diagram showing the main part of the electrical structure of the combine harvester.

[0052] Figure 16 It is a flowchart showing the process of driving control of the moisture sensor.

[0053] Figure 17 It is a flowchart showing the process of sensor burial countermeasure processing.

[0054] Explanation of Reference Numerals

[0055] First Embodiment

[0056] 1: Combine harvester

[0057] 32: Moisture sensor

[0058] 61, 62: Electrode rollers

[0059] 71: Control device

[0060] Second Embodiment

[0061] 1: Combine harvester

[0062] 5: Grain tank

[0063] 32: Moisture sensor

[0064] 61, 62: Electrode rollers

[0065] 71: Control device

[0066] 74: Paddy rice sensor (arrival sensor) Detailed implementation mode

[0067] Hereinafter, the implementation modes of the present invention will be described in detail with reference to the accompanying drawings.

[0068] <Overall structure of the combine harvester>

[0069] Figure 1 It is a right view of the combine harvester 1 according to an embodiment of the present invention.

[0070] The combine harvester 1 is an example of a harvester that travels in a field while harvesting cereal straws and threshing them from the cereal straws. The combine harvester 1 employs a pair of left and right crawlers 2 as traveling devices having the ability to travel on uneven ground such as fields, and a cab 4 and a grain tank 5 are provided on a machine body 3 supported by the pair of left and right crawlers 2.

[0071] The cab 4 is disposed at the front end of the crawler 2. The cab 4 provides a space inside for a driver to board, and operation components such as a driver's seat, an operation lever, and an operation pedal for the driver are disposed in this space. A door 6 that can be opened and closed is provided on the right side surface of the cab 4, and the driver can open the door 6 and enter the cab 4.

[0072] The grain tank 5 is disposed behind the cab 4 on the crawler 2.

[0073] In addition, a harvesting device 7 and a threshing device (not shown) are provided on the machine body 3 of the combine harvester 1. The harvesting device 7 is disposed on the front side of the crawler 2 and harvests the cereal straws standing upright in the field as the combine harvester 1 advances. The threshing device is disposed on the left side of the grain tank 5, conveys the root side of the cereal straws harvested by the harvesting device 7 to the rear side through a threshing supply chain, and supplies the ear tip side of the cereal straws to a threshing chamber for threshing. Moreover, the grains detached from the cereal straws are conveyed from the threshing device to the grain tank 5, and the grains are stored in the grain tank 5. An unloading device 8 is connected to the grain tank 5, and the grains stored in the grain tank 5 can be sent out by the unloading device 8 and discharged outside the machine.

[0074] <Internal structure of the grain tank>

[0075] Figure 2 It is a view of observing the inside of the grain tank 5 from the right side. Figure 3 It is a perspective view of the upper front part inside the grain tank 5.

[0076] As Figure 2 and Figure 3 shown, inside the grain tank 5, a conveying and discharging part 11 is provided at the upper front part. As Figure 3As shown, the conveying and discharging unit 11 integrally includes: a conveying unit 12 that conveys the grains sent out from the threshing device into the grain box 5; and a discharging unit 13 that discharges the grains conveyed by the conveying unit 12 into the grain box 5.

[0077] The conveying unit 12 extends from the front upper end of the left side wall 14 of the grain box 5 to the right side. The conveying unit 12 is provided with a conveying screw device 16 in a substantially cylindrical conveying box 15.

[0078] The conveying box 15 is connected to the left side wall 14. In the left side wall 14, in the portion surrounded by the conveying box 15, a circular opening is formed with a diameter substantially the same as the inner diameter of the conveying box 15.

[0079] The conveying screw device 16 includes a screw shaft 17 extending on the center line of the conveying box 15 and a spiral screw blade 18 supported on the screw shaft 17. The screw shaft 17 extends to the left side of the left side wall 14 through the opening of the left side wall 14. At the left end of the screw shaft 17, a pulley (not shown) is non-rotatably installed, and the conveying screw device 16 rotates by the driving force input to the pulley.

[0080] The discharging unit 13 is connected to the right end of the conveying unit 12 and supported by the conveying unit 12, and is disposed at the center in the left-right direction in the grain box 5 at a distance behind the front wall 21 of the grain box 5.

[0081] The discharging unit 13 includes a discharging box 22. The discharging box 22 has: a semi-cylindrical peripheral surface portion 23 bulging forward; a plate-shaped upper plate portion 24 extending rearward from the upper end of the peripheral surface portion 23; a plate-shaped guide plate portion 25 extending obliquely rearward and upward from the lower end of the peripheral surface portion 23; and an end surface portion 26 blocking the inner space of the peripheral surface portion 23 from the right side. An outlet 27 that communicates the inside of the discharging box 22 with the inside of the grain box 5 is opened between the upper plate portion 24 and the guide plate portion 25.

[0082] The screw shaft 17 enters the discharging box 22 and is rotatably inserted through the end surface portion 26 of the discharging box 22. In the discharging box 22, two rotating blades 28, 29 are supported on the screw shaft 17. The rotating blades 28, 29 are each formed in a substantially rectangular plate shape and extend from the screw shaft 17 to opposite sides of each other.

[0083] The rotating blades 28, 29 of the conveying screw device 16 rotate in the direction of passing through the outlet 27 from bottom to top. The grains sent out from the threshing device are conveyed in the conveying box 15 toward the discharging box 22 by the rotation of the screw blade 18. Then, the grains conveyed into the discharging box 22 are swept out by the rotating rotating blades 28, 29 and fly into the grain box 5 mainly in the direction along the upper surface of the guide plate portion 25 of the discharging box 22 from the outlet 27.

[0084] Figure 4 It is a perspective view of the rear end portion inside the grain box 5.

[0085] A moisture sensor 32 for measuring the moisture content of the grains is installed on the rear wall 31 of the grain box 5. The moisture sensor 32 penetrates the rear wall 31, and its front end portion protrudes into the grain box 5 from the inner surface of the rear wall 31, that is, the rear surface 33 inside the grain box 5. The moisture sensor 32 is arranged on the rear surface 33 at a position above the center in the vertical direction and lower than the discharge port 27 of the discharge portion 13, and is arranged on the right side of the center in the left-right direction (a position close to the right end). Specifically, taking the flow rate of the grains scattered from the discharge port 27 as a certain flow rate, the arrival position of the grains containing a certain amount of moisture or more and flying out from the discharge port 27 in the direction along the guide plate portion 25 and describing a parabola and scattering on the rear surface 33 is obtained through experiments or simulations, and the moisture sensor 32 is arranged at the obtained arrival position.

[0086] Figure 5 It is a perspective view of the moisture sensor 32.

[0087] The moisture sensor 32 includes a box-shaped sensor box 41. A receiving port 42 for receiving grains inside the sensor box 41 is formed on the front surface of the sensor box 41. The receiving port 42 has a bilaterally symmetric shape and includes: a V-shaped lower edge 43 that is open at the upper side; a first left side 44 that extends upward from the left upper end of the lower edge 43 at a relatively small angle with respect to the vertical direction (vertical direction) to the left; a second left side 45 that extends upward from the upper end of the first left side 44 at a relatively large angle with respect to the vertical direction to the left; a first right side 46 that extends upward from the right upper end of the lower edge 43 at a relatively small angle with respect to the vertical direction to the right; and a second right side 47 that extends upward from the upper end of the first right side 46 at a relatively large angle with respect to the vertical direction to the right. Planes 51, 52, 53, and 54 extend rearward from the first left side 44, the second left side 45, the first right side 46, and the second right side 47 respectively, and these planes 51, 52, 53, and 54 function as guide surfaces for guiding the grains into the sensor box 41.

[0088] Inside the sensor box 41, a pair of electrode rollers 61, 62 are provided in the roller accommodation space at the rear side of the receiving port 42. The electrode rollers 61, 62 integrally have roller shafts 63, 64 that extend parallel to each other in the front-rear direction. The circumferential surfaces of the electrode rollers 61, 62 are arranged close to each other in the left-right direction. A plurality of minute irregularities are formed on the circumferential surfaces of the electrode rollers 61, 62.

[0089] A DC motor (not shown) is provided inside the sensor box 41. By the driving force of this DC motor, a pair of electrode rollers 61 and 62 rotate forward and backward. During the forward rotation of the electrode rollers 61 and 62, when observed from inside the grain box 5, the electrode roller 61 rotates counterclockwise and the electrode roller 62 rotates clockwise. During the reverse rotation of the electrode rollers 61 and 62, when observed from inside the grain box 5, the electrode roller 61 rotates clockwise and the electrode roller 62 rotates counterclockwise.

[0090] In addition, a guide member 65 is provided inside the sensor box 41. The guide member 65 is rotatably supported relative to the roller shaft 63 of the left electrode roller 61. However, since there is an appropriate frictional resistance between it and the roller shaft 63, it is driven to rotate by the roller shaft 63 in a state where no external force other than the roller shaft 63 acts on the guide member 65. A stopper for restricting the rotation range of the guide member 65 is provided inside the sensor box 41. As a result, the guide member 65 is disposed at a position on the front upper side of the electrode rollers 61 and 62 during the forward rotation of the electrode rollers 61 and 62, and is disposed at a position on the upper left side (the position on the left front upper side of the electrode rollers 61 and 62) relative to the position during the forward rotation during the reverse rotation of the electrode rollers 61 and 62. The guide member 65 is substantially triangular in plan view and substantially V-shaped that opens upward in front view in a state where it is disposed at a position on the front upper side of the electrode rollers 61 and 62.

[0091] A part of the grains scattered from the discharge port 27 of the discharge unit 13 reaches the position of the sensor box 41 and is received inside the sensor box 41 from the receiving port 42 of the sensor box 41. During the forward rotation of the electrode rollers 61 and 62, since the guide member 65 is located at a position on the front upper side of the electrode rollers 61 and 62, the grains that fly in from the receiving port 42 and reach the guide member 65 are guided by the guide member 65 onto the electrode rollers 61 and 62. In addition, a part of the grains that fly into the sensor box 41 from the receiving port 42 directly reaches the electrode rollers 61 and 62. Moreover, the grains on the electrode rollers 61 and 62 are clamped and crushed by the forward rotation of the electrode rollers 61 and 62. In the moisture sensor 32, the resistance value between the electrode rollers 61 and 62 when the grains are crushed is detected, and the value of the moisture content contained in the grains is obtained based on this resistance value. Then, the obtained value (detection operation) is output from the moisture sensor 32.

[0092] It should be noted that it may also be configured such that the resistance value between the electrode rollers 61 and 62 when the grains are crushed is output from the moisture sensor 32, and in the control device to which the output value of the moisture sensor 32 is input, the value of the moisture content contained in the grains is obtained based on the resistance value.

[0093] In addition, when the electrode rollers 61 and 62 reverse, a brush (not shown) abuts against the circumferential surfaces of the electrode rollers 61 and 62, and the circumferential surfaces (surfaces) of the electrode rollers 61 and 62 are cleaned (cleaning operation). At this time, the guide member 65 retracts from the position on the front upper side of the electrode rollers 61 and 62 to the position on the upper left side. Therefore, it does not interfere with the uncrushed grains falling from the electrode rollers 61 and 62.

[0094] The bottom surface of the roller accommodation space that houses the electrode rollers 61 and 62 is open. Therefore, the grains received into the sensor box 41 from the receiving port 42 do not accumulate in the roller accommodation space except on the electrode rollers 61 and 62, but return to the grain box 5 from the roller accommodation space through a return passage 66 provided below the moisture sensor 32 (see Figure 4 ).

[0095] <Electrical Structure of Combine Harvester>

[0096] Figure 6 It is a block diagram showing the main part of the electrical structure of the combine harvester 1.

[0097] In the combine harvester 1, a control device 71 is mounted to control the operation of the moisture sensor 32. The control device 71 has a structure including a microcontroller unit (MCU: Micro Controller Unit). In the microcontroller unit, non-volatile memories such as a CPU and a flash memory, and volatile memories such as a DRAM (Dynamic Random Access Memory) are built in, for example.

[0098] In addition to the value (detection signal) output from the moisture sensor 32, a signal indicating the on / off state of the main key switch 72 and a detection signal from the straw sensor 73 are input to the control device 71. The main key switch 72 is a switch that is turned on / off by a user inserting a key into a lock cylinder at the start and end of the operation of the combine harvester 1. The straw sensor 73 is a sensor provided in the harvesting device 7 to detect the presence of straw in the harvesting device 7. The straw sensor 73 outputs a detection signal at an on level when there is straw in the harvesting device 7, and outputs a detection signal at an off level when there is no straw in the harvesting device 7.

[0099] <Sensor Drive Control>

[0100] Figure 7 It is a flowchart showing the process of the drive control of the moisture sensor 32.

[0101] When the main key switch 72 is turned on, the control of the drive (operation) of the moisture sensor 32 is started by the control device 71. The drive control of the moisture sensor 32 continues until the main key switch 72 is turned off.

[0102] In the drive control of the moisture sensor 32, according to the situation where the main key switch 72 is turned on, the DC motor of the moisture sensor 32 is controlled to reverse the electrode rollers 61 and 62 within a predetermined normal time (step S1). Thus, the moisture sensor 32 performs a cleaning operation within the normal time. Through the cleaning operation, the circumferential surfaces of the electrode rollers 61 and 62 are cleaned.

[0103] Thereafter, it is determined whether the harvesting device 7 and the threshing device are operating (turned on) (step S2). When the harvesting device 7 and the threshing device are in a non-operating state (turned off) (No in step S2), before the harvesting device 7 and the threshing device start operating, the drive control of the moisture sensor 32 is not advanced.

[0104] If it is determined that the harvesting device 7 and the threshing device are operating (Yes in step S2), the electrode rollers 61 and 62 are reversed within the normal time. Thus, the moisture sensor 32 performs a cleaning operation within the normal time.

[0105] When the normal time has elapsed since the start of the cleaning operation, the electrode rollers 61 and 62 are rotated forward within a specified time (step S4). The specified time is set to the time required for the guide member 65 disposed at the upper left front position of the electrode rollers 61 and 62 to move to the upper front position of the electrode rollers 61 and 62. Therefore, by rotating the electrode rollers 61 and 62 forward within the specified time, the guide member 65 moves from the upper left front position of the electrode rollers 61 and 62 to the upper front position of the electrode rollers 61 and 62.

[0106] Thereafter, it is determined whether the detection signal of the straw sensor 73 is at an on level (step S5). During the period when the detection signal of the straw sensor 73 is at an off level (No in step S5), the drive control of the moisture sensor 32 is not advanced.

[0107] When straw enters the harvesting device 7 and the detection signal of the straw sensor 73 becomes on (Yes in step S5), the resistance value between the electrode rollers 61 and 62 is detected, and based on this resistance value, it is determined whether there are grains (crops) on the electrode rollers 61 and 62 (step S6). When there are grains on the electrode rollers 61 and 62, even if the grains are not crushed, the resistance value between the electrode rollers 61 and 62 is different from the resistance value between the electrode rollers 61 and 62 when there are no grains on the electrode rollers 61 and 62. Therefore, it is possible to determine whether there are grains on the electrode rollers 61 and 62 based on the resistance value between the electrode rollers 61 and 62.

[0108] When there are no grains on the electrode rollers 61 and 62 (No in step S6), it is again determined whether the detection signal of the straw sensor 73 is at an on level (step S5).

[0109] When the grains come onto the electrode rollers 61 and 62 and it is determined that there are grains on the electrode rollers 61 and 62 (Yes in step S6), the electrode rollers 61 and 62 rotate forward, the resistance value between the electrode rollers 61 and 62 during the crushing of the grains by the electrode rollers 61 and 62 is detected, and the value of the moisture content contained in the grains is obtained based on this resistance value. That is, in order to measure the moisture content contained in the grains, the moisture sensor 32 performs a detection operation of detecting the resistance value between the electrode rollers 61 and 62 during the crushing of the grains.

[0110] If the moisture content of the grains is measured, the electrode rollers 61 and 62 are rotated in reverse during normal time (step S8). Thereby, the moisture sensor 32 performs a cleaning operation during normal time.

[0111] After the cleaning operation of the moisture sensor 32 is completed, it is again determined whether the harvesting device 7 and the threshing device are operating (turned on) (step S2). If the harvesting device 7 and the threshing device are in an operating state (Yes in step S2), the processing after the above step S3 is executed. Thus, in the state where the harvesting device 7 and the threshing device are operating, the moisture content of the grains is periodically measured.

[0112] <First abnormality elimination process>

[0113] Figure 8 It is a flowchart showing the process of the first abnormality elimination process.

[0114] For example, if foreign matters such as cut straws (straw scraps) that are the cut ends of straws enter the sensor box 41 of the moisture sensor 32 and this foreign matter gets caught between the electrode rollers 61 and 62, there may be an abnormality that the electrode rollers 61 and 62 cannot rotate well (hereinafter referred to as "roller lock"). In addition, if it is left in a state where the crushed grains adhere to the electrode rollers 61 and 62, the grains are fixed to the electrode rollers 61 and 62, and roller lock may occur.

[0115] Therefore, through the control device 71, the first abnormality elimination process is executed in parallel with the drive control of the above moisture sensor 32. The first abnormality elimination process is a process of detecting roller lock and eliminating roller lock when roller lock is detected.

[0116] In the first abnormal elimination process, first, a determination for detecting roll locking is performed. That is, in order to detect roll locking, the motor drive current supplied to the DC motor that rotates the electrode rollers 61 and 62 of the moisture sensor 32 is detected. Next, it is determined whether this motor drive current is greater than a predetermined threshold value (step S11). The motor drive current being greater than the threshold value indicates that the rotational resistance of the electrode rollers 61 and 62 is large, and the electrode rollers 61 and 62 do not rotate well. Therefore, the determination of whether the motor drive current is greater than the threshold value is a determination for detecting roll locking, and when the motor drive current is greater than the threshold value, it can be determined that roll locking has occurred.

[0117] When it is determined that the motor drive current is greater than the threshold value (Yes in step S11), the supply of the motor drive current to the DC motor is stopped, and the electrode rollers 61 and 62 stop (step S12).

[0118] Next, it is determined whether the electrode rollers 61 and 62 rotated forward or backward before stopping (step S13).

[0119] When the electrode rollers 61 and 62 rotated forward before stopping (Yes in step S13), the DC motor is controlled to reverse the electrode rollers 61 and 62 within a predetermined normal time (step S14). Thereby, the moisture sensor 32 performs a cleaning operation within the normal time, which is an abnormal elimination operation for eliminating roll locking. Through the cleaning operation, the circumferential surfaces of the electrode rollers 61 and 62 are cleaned. Therefore, there is a possibility that the roll locking caused by crushed grains being fixed to the electrode rollers 61 and 62 is eliminated. In addition, the roll locking caused by being caught between the electrode rollers 61 and 62 may be eliminated by reversing the electrode rollers 61 and 62.

[0120] On the other hand, when the electrode rollers 61 and 62 rotated backward before stopping (No in step S13), that is, when the moisture sensor 32 has performed a cleaning operation, there is no method for eliminating roll locking. Therefore, an abnormal alarm is issued to notify the user of the occurrence of an abnormality (step S15).

[0121] <Second Abnormal Elimination Process>

[0122] Figure 9 It is a flowchart showing the process of the second abnormal elimination process.

[0123] For example, if there is a large amount of moisture in the grains, an abnormality in which crushed grains adhere to the electrode rollers 61 and 62 (hereinafter referred to as "roll clogging") may occur. In this abnormal state, if the next measurement of the moisture content of the grains is performed, it may not be possible to accurately measure this moisture content.

[0124] Therefore, through the control device 71, the second abnormality elimination process is executed in parallel with the drive control of the moisture sensor 32 described above. The second abnormality elimination process is a process of detecting a roll jam and eliminating the roll jam when the roll jam is detected.

[0125] In the second abnormality elimination process, first, a determination for detecting a roll jam is performed. That is, in order to detect a roll jam, during the reverse rotation of the electrode rollers 61 and 62 of the moisture sensor 32, that is, during the cleaning operation of the moisture sensor 32, the resistance value between the electrode rollers 61 and 62 is detected. Next, it is determined whether this detected value is an abnormal value (step S21). When grains adhere to the electrode rollers 61 and 62, current flows between the electrode rollers 61 and 62 through the grains. Therefore, compared with the case where grains do not adhere to the electrode rollers 61 and 62, the detected value indicating the resistance value between the electrode rollers 61 and 62 is an abnormal value that is significantly reduced. Therefore, the determination of whether the detected value of the resistance value between the electrode rollers 61 and 62 is an abnormal value is a determination for detecting a roll jam. When the resistance value between the electrode rollers 61 and 62 is an abnormal value, it can be determined that a roll jam has occurred.

[0126] When the detected value of the resistance value between the electrode rollers 61 and 62 is an abnormal value (Yes in step S21), the electrode rollers 61 and 62 are rotated in reverse for a time longer than the normal time (step S22). Thereby, the moisture sensor 32 performs the cleaning operation for a longer time than usual, as an abnormality elimination operation for eliminating the roll jam. By performing the cleaning operation for a longer time usually, grains are removed from the circumferential surfaces of the electrode rollers 61 and 62, and it is possible to eliminate the roll jam.

[0127] Thereafter, it is determined whether a roll jam has occurred multiple times (step S23). If a roll jam has not occurred multiple times (No in step S23), the detected value of the resistance value between the electrode rollers 61 and 62 is determined again (step S21).

[0128] Moreover, when a roll jam occurs multiple times, the roll jam is detected multiple times, and accordingly, when the cleaning operation for a longer time than usual is performed multiple times, the possibility that the roll jam is not eliminated is high. Therefore, an abnormality alarm is issued to inform the user of the occurrence of the abnormality (step S24).

[0129] <Function and effect>

[0130] As described above, by performing the determination for detecting an abnormality (roll lock, roll jam) of the moisture sensor 32, it is possible to detect an abnormality of the moisture sensor 32. Moreover, when an abnormality of the moisture sensor 32 is detected, the abnormality can be eliminated by the abnormality elimination operation of the moisture sensor 32.

[0131] <Modification example>

[0132] As described above, an embodiment of the present invention has been described, but the present invention can also be implemented in other ways.

[0133] For example, in order to detect roll locking, it is determined whether the motor drive current supplied to the DC motor that rotates the electrode rollers 61 and 62 of the moisture sensor 32 is larger than a predetermined threshold value. The determination for detecting roll locking is not limited to this. For example, when the rotational speed of the electrode rollers 61 and 62 or the rotational speed of the DC motor that rotates the electrode rollers 61 and 62 can be detected, it may also be a determination of whether the detected rotational speed is less than a predetermined threshold value.

[0134] In addition, in the above structure, various design changes can be made within the scope of the matters described in the scope of protection of the claims.

[0135] Second Embodiment

[0136] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[0137] <Overall Structure of Combine Harvester>

[0138] Figure 10 It is a right view of a combine harvester 1 according to an embodiment of the present invention.

[0139] The combine harvester 1 is an example of a harvester that travels in a field while harvesting cereal straws and threshing the cereal straws. The combine harvester 1 employs a pair of left and right crawlers 2 as traveling devices having the ability to travel on uneven ground such as a field, and a cab 4 and a grain tank 5 are provided on a machine body 3 supported by the pair of left and right crawlers 2.

[0140] The cab 4 is disposed at the front end of the crawler 2. The cab 4 provides a space for a driver to ride inside, and operation components such as a driver's seat, an operation lever, and operation pedals for the driver are disposed in this space. A door 6 that can be opened and closed is provided on the right side surface of the cab 4, and the driver can open the door 6 and enter the cab 4.

[0141] The grain tank 5 is disposed behind the cab 4 on the crawler 2.

[0142] In addition, a harvesting device 7 and a threshing device (not shown) are provided on the body 3 of the combine harvester 1. The harvesting device 7 is disposed on the front side of the crawler 2 and harvests the standing cereal straws in the field as the combine harvester 1 advances. The threshing device is disposed on the left side of the grain tank 5, conveys the root side of the cereal straws harvested by the harvesting device 7 to the rear side through a threshing supply chain, and supplies the spike tip sides of the cereal straws to the threshing chamber for threshing. Moreover, the grains detached from the cereal straws are conveyed from the threshing device to the grain tank 5, and the grains are stored in the grain tank 5. An unloading device 8 is connected to the grain tank 5, and the grains stored in the grain tank 5 can be sent out by the unloading device 8 and discharged outside the machine.

[0143] <Internal Structure of Grain Tank>

[0144] Figure 11 FIG. is a view of the inside of the grain tank 5 as observed from the right side. Figure 12 FIG. is a perspective view of the upper front end inside the grain tank 5.

[0145] As Figure 11 and Figure 12 shown, inside the grain tank 5, a conveying and discharging portion 11 is provided at the upper front end. As Figure 12 shown, the conveying and discharging portion 11 integrally includes: a conveying portion 12 that conveys the grains sent out from the threshing device into the grain tank 5; and a discharging portion 13 that discharges the grains conveyed by the conveying portion 12 into the grain tank 5.

[0146] The conveying portion 12 extends from the front upper end portion of the left side wall 14 of the grain tank 5 toward the right side. The conveying portion 12 includes a conveying screw device 16 inside a substantially cylindrical conveying box 15.

[0147] The conveying box 15 is connected to the left side wall 14. In the left side wall 14, in the portion surrounded by the conveying box 15, a circular opening is formed with a diameter substantially the same as the inner diameter of the conveying box 15.

[0148] The conveying screw device 16 includes a screw shaft 17 extending on the center line of the conveying box 15 and a spiral screw blade 18 supported by the screw shaft 17. The screw shaft 17 extends to the left side of the left side wall 14 through the opening of the left side wall 14. At the left end portion of the screw shaft 17, a pulley (not shown) is non-rotatably installed, and the conveying screw device 16 rotates by the driving force input to the pulley.

[0149] The discharging portion 13 is connected to the right end of the conveying portion 12 and supported by the conveying portion 12, and is disposed at an interval behind the front wall 21 of the grain tank 5 at the central portion in the left-right direction inside the grain tank 5.

[0150] The discharge section 13 includes a discharge box 22. The discharge box 22 has: a semi-cylindrical peripheral surface portion 23 bulging forward; a plate-like upper plate portion 24 extending rearward from the upper end of the peripheral surface portion 23; a plate-like guide plate portion 25 extending obliquely rearward and upward from the lower end of the peripheral surface portion 23; and an end surface portion 26 blocking the inner space of the peripheral surface portion 23 from the right side. An outlet 27 that communicates the inside of the discharge box 22 with the inside of the grain box 5 is open between the upper plate portion 24 and the guide plate portion 25.

[0151] The spiral shaft 17 enters the discharge box 22 and is rotatably inserted through the end surface portion 26 of the discharge box 22. Inside the discharge box 22, two rotating blades 28, 29 are supported on the spiral shaft 17. The rotating blades 28, 29 are each formed in a substantially rectangular plate shape and extend from the spiral shaft 17 toward opposite sides.

[0152] The rotating blades 28, 29 of the conveying spiral device 16 rotate in the direction of passing through the outlet 27 from bottom to top. The grains sent out from the threshing device are conveyed toward the discharge box 22 in the conveying box 15 by the rotation of the spiral blade 18. Then, the grains conveyed into the discharge box 22 are swept out by the rotating rotating blades 28, 29 and fly into the grain box 5 mainly in the direction along the upper surface of the guide plate portion 25 of the discharge box 22 from the outlet 27.

[0153] Figure 13 It is a perspective view of the rear end portion inside the grain box 5.

[0154] A moisture sensor 32 for measuring the moisture content of the grains is installed on the rear wall 31 of the grain box 5. The moisture sensor 32 penetrates the rear wall 31, and its front end portion is exposed into the grain box 5 from the inner surface of the rear wall 31, that is, the rear surface 33 inside the grain box 5. The moisture sensor 32 is arranged on the rear surface 33 at a position higher than the center in the vertical direction and lower than the outlet 27 of the discharge section 13, and is arranged at a position biased to the right side (a position closer to the right end) than the center in the left-right direction. Specifically, taking the flow rate of the grains scattered from the outlet 27 as a certain flow rate, the arrival position of the grains containing a certain amount of moisture or more and flying out from the outlet 27 in the direction along the guide plate portion 25 and depicting a parabola and scattering on the rear surface 33 is obtained through experiments or simulations, and the moisture sensor 32 is arranged at the obtained arrival position.

[0155] Figure 14 It is a perspective view of the moisture sensor 32.

[0156] The moisture sensor 32 includes a box-shaped sensor box 41. A receiving port 42 for receiving grains is formed on the front surface of the sensor box 41. The receiving port 42 has a bilaterally symmetric shape and includes: a lower edge 43 of a V shape that is open at the upper side; a first left side 44 that extends upward from the upper left end of the lower edge 43 at a relatively small angle with respect to the vertical direction; a second left side 45 that extends upward from the upper end of the first left side 44 at a relatively large angle with respect to the vertical direction; a first right side 46 that extends upward from the upper right end of the lower edge 43 at a relatively small angle with respect to the vertical direction; and a second right side 47 that extends upward from the upper end of the first right side 46 at a relatively large angle with respect to the vertical direction. Planes 51, 52, 53, and 54 extend rearward from the first left side 44, the second left side 45, the first right side 46, and the second right side 47, respectively, and these planes 51, 52, 53, and 54 function as guiding surfaces for guiding grains into the sensor box 41.

[0157] Inside the sensor box 41, a pair of electrode rollers 61, 62 are provided in a roller accommodation space at the rear side of the receiving port 42. The electrode rollers 61, 62 integrally have roller shafts 63, 64 that extend in the front-rear direction parallel to each other. The circumferential surfaces of the electrode rollers 61, 62 are arranged close to each other in the left-right direction. A plurality of minute irregularities are formed on the circumferential surfaces of the electrode rollers 61, 62.

[0158] A DC motor (not shown) is provided inside the sensor box 41, and by the driving force of this DC motor, the pair of electrode rollers 61, 62 rotate forward and backward. During the forward rotation of the electrode rollers 61, 62, when viewed from inside the grain box 5, the electrode roller 61 rotates counterclockwise and the electrode roller 62 rotates clockwise. During the reverse rotation of the electrode rollers 61, 62, when viewed from inside the grain box 5, the electrode roller 61 rotates clockwise and the electrode roller 62 rotates counterclockwise.

[0159] In addition, a guiding member 65 is provided inside the sensor box 41. The guiding member 65 is rotatably supported relative to the roller shaft 63 of the left electrode roller 61, but due to having an appropriate frictional resistance between it and the roller shaft 63, it is driven to rotate by the roller shaft 63 in a state where no external force other than the roller shaft 63 acts on the guiding member 65. A stopper for restricting the rotation range of the guiding member 65 is provided inside the sensor box 41. As a result, the guiding member 65 is disposed at a position on the front upper side of the electrode rollers 61, 62 during the forward rotation of the electrode rollers 61, 62, and is disposed at a position on the upper left side (the position on the left front upper side of the electrode rollers 61, 62) relative to the position during the forward rotation during the reverse rotation of the electrode rollers 61, 62. The guiding member 65 is substantially triangular when viewed from above and has a substantially V shape that is open upward when viewed from the front in a state where it is disposed at the position on the front upper side of the electrode rollers 61, 62.

[0160] A part of the grains scattered from the discharge port 27 of the discharge unit 13 reaches the position of the sensor box 41 and is received into the sensor box 41 through the receiving port 42 of the sensor box 41. When the electrode rollers 61 and 62 rotate forward, the guide member 65 is located at the upper front side position of the electrode rollers 61 and 62. Therefore, the grains that fly into the guide member 65 after flying in from the receiving port 42 are guided by the guide member 65 onto the electrode rollers 61 and 62. In addition, a part of the grains that fly into the sensor box 41 from the receiving port 42 directly reaches the electrode rollers 61 and 62. Moreover, the grains on the electrode rollers 61 and 62 are clamped by the electrode rollers 61 and 62 during the forward rotation of the electrode rollers 61 and 62 and are crushed. In the moisture sensor 32, the resistance value between the electrode rollers 61 and 62 when the grains are crushed is detected, and the value of the moisture content contained in the grains is obtained based on this resistance value. Then, the obtained value (detection operation) is output from the moisture sensor 32.

[0161] It should be noted that it can also be configured such that the resistance value between the electrode rollers 61 and 62 when the grains are crushed is output from the moisture sensor 32, and in the control device to which the output value of the moisture sensor 32 is input, the value of the moisture content contained in the grains is obtained based on the resistance value.

[0162] In addition, when the electrode rollers 61 and 62 rotate in reverse, a brush (not shown) abuts against the circumferential surfaces of the electrode rollers 61 and 62, and the circumferential surfaces (surfaces) of the electrode rollers 61 and 62 are cleaned (cleaning operation). At this time, the guide member 65 retracts from the upper front side position of the electrode rollers 61 and 62 to the upper left side position, so that it does not prevent the uncrushed grains from falling from the electrode rollers 61 and 62.

[0163] The bottom surface of the roller accommodation space that accommodates the electrode rollers 61 and 62 is open. Therefore, the grains received into the sensor box 41 from the receiving port 42 do not accumulate in the roller accommodation space except on the electrode rollers 61 and 62, but return to the grain box 5 from the roller accommodation space through the return passage 66 provided below the moisture sensor 32 (refer to Figure 13 ).

[0164] <Electrical Structure of the Combine Harvester>

[0165] Figure 15 It is a block diagram showing the main part of the electrical structure of the combine harvester 1.

[0166] In the combine harvester 1, a control device 71 is mounted to control the operation of the moisture sensor 32. The control device 71 includes a microcontroller unit (MCU). In the microcontroller unit, there are, for example, a non-volatile memory such as a CPU and a flash memory, and a volatile memory such as a DRAM (Dynamic Random Access Memory).

[0167] In addition to the value (detection signal) output from the moisture sensor 32, the on / off signal of the main key switch 72, the detection signal of the straw sensor 73, and the detection signal of the paddy sensor 74 are input to the control device 71. The main key switch 72 is a switch that is turned on / off by the user inserting a key into the lock cylinder at the start (starting) and end of the operation of the combine harvester 1. The straw sensor 73 is a sensor provided in the harvesting device 7 to detect the presence of straw in the harvesting device 7. The straw sensor 73 outputs a detection signal of an on level when there is straw in the harvesting device 7, and outputs a detection signal of an off level when there is no straw in the harvesting device 7. As Figure 13 shown, the paddy sensor 74 has the following structure, for example: it is arranged at a detection position near the lower end of the moisture sensor 32. When the height of the grains piled up in the grain tank 5 reaches the detection position, the pressure-sensitive part is pressed by the grains, and the limit switch is turned on by this pressing.

[0168] <Sensor drive control>

[0169] Figure 16 is a flowchart showing the process of the drive control of the moisture sensor 32.

[0170] When the main key switch 72 is turned on, the control of the drive (operation) of the moisture sensor 32 is started by the control device 71. The drive control of the moisture sensor 32 continues until the main key switch 72 is turned off.

[0171] In the drive control of the moisture sensor 32, according to the situation where the main key switch 72 is turned on, the DC motor of the moisture sensor 32 is controlled to reverse the electrode rollers 61 and 62 within a predetermined normal time (step S1). Thus, the moisture sensor 32 performs a cleaning operation within the normal time. Through the cleaning operation, the circumferential surfaces of the electrode rollers 61 and 62 are cleaned.

[0172] Thereafter, it is determined whether the harvesting device 7 and the threshing device are operating (on) (step S2). In the case where the harvesting device 7 and the threshing device are in a non-operating state (off) (No in step S2), the drive control of the moisture sensor 32 is not advanced until the harvesting device 7 and the threshing device start operating.

[0173] If it is determined that the harvesting device 7 and the threshing device are operating (Yes in step S2), the electrode rollers 61 and 62 are reversely rotated during the normal time. Thereby, the moisture sensor 32 performs a cleaning operation during the normal time.

[0174] When the normal time has elapsed since the start of the cleaning operation, the electrode rollers 61 and 62 are rotated forward within a specified time (step S4). The specified time is set to the time required for the guide member 65 disposed at the upper left front position of the electrode rollers 61 and 62 to move to the upper front position of the electrode rollers 61 and 62. Therefore, by rotating the electrode rollers 61 and 62 forward within the specified time, the guide member 65 moves from the upper left front position of the electrode rollers 61 and 62 to the upper front position of the electrode rollers 61 and 62.

[0175] Thereafter, it is determined whether the detection signal of the straw sensor 73 is at the conduction level (step S5). During the period when the detection signal of the straw sensor 73 is at the non-conduction level (No in step S5), the drive control of the moisture sensor 32 is not advanced.

[0176] When straw enters the harvesting device 7 and the detection signal of the straw sensor 73 becomes at the conduction level (Yes in step S5), the resistance value between the electrode rollers 61 and 62 is detected, and based on this resistance value, it is determined whether there are grains (crops) on the electrode rollers 61 and 62 (step S6). When there are grains on the electrode rollers 61 and 62, even if the grains are not crushed, the resistance value between the electrode rollers 61 and 62 is different from the resistance value between the electrode rollers 61 and 62 when there are no grains on the electrode rollers 61 and 62. Therefore, it is possible to determine whether there are grains on the electrode rollers 61 and 62 based on the resistance value between the electrode rollers 61 and 62.

[0177] When there are no grains on the electrode rollers 61 and 62 (No in step S6), it is again determined whether the detection signal of the straw sensor 73 is at the conduction level (step S5).

[0178] When grains come onto the electrode rollers 61 and 62 and it is determined that there are grains on the electrode rollers 61 and 62 (Yes in step S6), the electrode rollers 61 and 62 are rotated forward, and the resistance value between the electrode rollers 61 and 62 when the grains are crushed by the electrode rollers 61 and 62 is detected, and the value of the moisture content contained in the grains is obtained based on this resistance value. That is, the moisture sensor 32 performs a detection operation of detecting the resistance value between the electrode rollers 61 and 62 when the grains are crushed in order to measure the moisture content contained in the grains.

[0179] If the moisture content of the grains is measured, the electrode rollers 61 and 62 are reversely rotated during the normal time (step S8). Thereby, the moisture sensor 32 performs a cleaning operation during the normal time.

[0180] After the cleaning operation of the moisture sensor 32 is completed, it is determined again whether the harvesting device 7 and the threshing device are operating (turned on) (step S2). If the harvesting device 7 and the threshing device are in an operating state (Yes in step S2), the processing after step S3 described above is executed. Thus, in a state where the harvesting device 7 and the threshing device are operating, the moisture content of the grains is periodically measured.

[0181] <Sensor burial countermeasure processing>

[0182] Figure 17 It is a flowchart showing the process of the sensor burial countermeasure processing.

[0183] If the operation of the harvesting device 7 and the threshing device continues, grains accumulate in the grain tank 5, and the height of the accumulated grains increases. In a state where the harvesting device 7 and the threshing device are operating, the moisture content of the grains is periodically measured. However, if the moisture sensor 32 is buried by the grains, the following situation may occur: the grains clog in the sensor box 41 of the moisture sensor 32, and even if the moisture sensor 32 is operated, it will not operate properly.

[0184] Therefore, the control device 71 executes Figure 17 the sensor burial countermeasure processing shown.

[0185] In the sensor burial countermeasure processing, first, it is determined whether the current state of the moisture sensor 32 (the state in the grain tank 5) is a state where burial is feared (step S11). The burial risk state is the state prior to the state where the moisture sensor 32 is buried by the grains accumulated in the grain tank 5. Specifically, it is a state where the height of the accumulated grains reaches the detection position of the paddy sensor 74 and the paddy sensor 7 is turned on.

[0186] If it is not determined to be a burial risk state (No in step S11), the sensor burial countermeasure processing is temporarily terminated and executed again after a specified time has elapsed.

[0187] If it is determined to be a burial risk state (Yes in step S11), the operation of the moisture sensor 32 is prohibited (step S12). The prohibited operations include not only the detection operation but also the cleaning operation. That is, all operations of the moisture sensor 32 are prohibited.

[0188] After the operation of the moisture sensor 32 is prohibited, it is determined whether the burial risk state has been eliminated (step S13). That is, it is determined whether the paddy sensor 74 in the on state has switched to the off state.

[0189] By the unloading device 8 (refer to Figure 10) Grains are sent out from the grain box 5, and the amount of grains in the grain box 5 decreases. When the height of the grains piled up in the grain box 5 is lower than the detection position of the paddy sensor 74, the paddy sensor 74 switches from the on state to the off state. When the paddy sensor 74 becomes the off state, it is determined that the buried danger state is eliminated (Yes in step S13).

[0190] If the buried danger state is eliminated, the operation prohibition of the moisture sensor 32 is released. Then, the DC motor of the moisture sensor 32 is controlled to reverse the electrode rollers 61 and 62 within the normal time (step S14). Thereby, the moisture sensor 32 performs a cleaning operation within the normal time. Through the cleaning operation, the circumferential surfaces of the electrode rollers 61 and 62 are cleaned, and the grains remaining on the electrode rollers 61 and 62 fall off.

[0191] <Effect>

[0192] As described above, the moisture sensor 32 for measuring the moisture content of grains receives the grains discharged into the grain box 5. The discharge of grains into the grain box 5 is promoted. If the moisture sensor 32 enters a state prior to the state of being buried in the grains stored in the grain box 5, that is, the buried danger state, the operation of the moisture sensor 32 is prohibited. Thus, even if the moisture sensor 32 becomes buried in the grains, the operation of the moisture sensor 32 is originally prohibited, and the moisture sensor 32 is not instructed to operate. Therefore, it is possible to prevent a situation where the moisture sensor 32 does not operate well even when it is made to operate. As a result, false alarms of abnormalities in the moisture sensor 32 can be suppressed.

[0193] In addition, according to the situation where the buried danger state is eliminated, the operation prohibition of the moisture sensor 32 is released. Moreover, through the reversal of the electrode rollers 61 and 62, the moisture sensor 32 performs a cleaning operation. Thereby, the clogging of grains in the moisture sensor 32 can be eliminated, and good operation of the moisture sensor 32 can be ensured.

[0194] <Modification Example>

[0195] The above describes one embodiment of the present invention, but the present invention can also be implemented in other ways.

[0196] For example, in the above embodiment, the paddy sensor 74 is arranged at the detection position near the lower end of the moisture sensor 32, and when the paddy sensor 74 is turned on, it is detected that the height of the grains piled up in the grain box 5 has reached the detection position. Instead of the paddy sensor 74, as an arrival sensor, a non-contact sensor for non-contact detection of the grains piled up in the grain box 5 can be arranged at the detection position, and when the non-contact sensor is turned on, it is detected that the height of the grains piled up in the grain box 5 has reached the detection position.

[0197] In addition, in the above structure, various design changes can be implemented within the scope of the matters recited in the scope of protection of the claims.

Claims

1. A combine harvester, wherein, The combine harvester comprises: a moisture sensor including a pair of electrode rollers, the pair of electrode rollers rotating forward in a direction of rolling up the grains between the electrode rollers, crushing the grains between the electrode rollers, performing a detection operation of detecting a resistance value between the electrode rollers when the grains are crushed, and performing a cleaning operation of cleaning the surfaces of the electrode rollers by reversing the pair of electrode rollers; and a control device, wherein the control device controls the action of the moisture sensor, The control device performs a determination for detecting an abnormality of the moisture sensor during the rotation of the pair of electrode rollers, and when an abnormality of the moisture sensor is detected by the determination, causes the moisture sensor to perform an abnormality elimination operation in order to eliminate the abnormality. The control device determines whether the resistance value between the electrode rollers in the cleaning action is an abnormal value, detects the abnormality of the moisture sensor based on the determination that the resistance value is the abnormal value, and when the abnormality is detected in the cleaning action within the normal time, the cleaning action is continued for a time longer than the normal time as the abnormality elimination action.

2. The combine harvester according to claim 1, wherein: The control device determines whether the driving current of the motor that rotates the pair of electrode rollers exceeds a threshold value, detects an abnormality in the moisture sensor based on the determination that the current exceeds the threshold value, and when an abnormality is detected during the forward rotation of the pair of electrode rollers, as the abnormality elimination action, causes the moisture sensor to perform the cleaning action after stopping the pair of electrode rollers.

3. The combine harvester according to claim 2, wherein: The control device stops the pair of electrode rollers and issues an abnormality alarm when an abnormality is detected during the reverse rotation of the pair of electrode rollers in the cleaning operation.

4. The combine harvester according to claim 1, wherein: The control device issues an abnormality alarm when the abnormality of the moisture sensor is detected multiple times.

5. A combine harvester, wherein, The combine harvester comprises: a grain box storing grains; an unloading device for delivering the grains stored in the grain box from the grain box; a moisture sensor configured to receive grains discharged into the grain box, output a value corresponding to the moisture content of the grains according to a detection action, and perform self-cleaning through a cleaning action; and A control device, wherein the control device prohibits both the detection action and the cleaning action of the moisture sensor based on the detection of a previous stage of the buried state, i.e., a buried danger state, in which the moisture sensor is buried in the grains stored in the grain box, and releases the buried danger state by delivering the grains from the grain box through the unloading device, thereby causing the moisture sensor to perform the cleaning action.

6. The combine harvester according to claim 5, wherein: The moisture sensor includes a pair of electrode rollers. During the detection action, the pair of electrode rollers rotate in the direction of rolling up the grains between the electrode rollers, crushing the grains between the electrode rollers, detecting the resistance value between the electrode rollers during the crushing, and outputting a value corresponding to the moisture content of the grains. During the cleaning action, the pair of electrode rollers reverse to clean the surfaces of the electrode rollers.

7. The combine harvester according to claim 5 or 6, wherein: The combine harvester further includes an arrival sensor configured to detect that the grains stored in the grain tank have reached a detection position set below a position of the moisture sensor. The control device detects a state in which the arrival sensor detects that the grains have arrived at the detection position as the buried danger state.

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